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The  D.  Van  Noftrand  Company 

intend  this  book  to  be  sold  to  the  Public 
at  the  advertised  price,  and  supply  it  to 
the  Trade  on  terms  which  will  not  allow 
of  reduction. 


AMERICAN 
PRODUCER  GAS  PRACTICE 


AND 


INDUSTRIAL  GAS  ENGINEERING 


BY 

NISBET   LATTA 

ii 

CONSULTING   ENGINEER 
Author  of   "American  Gas  Engineering  Practice" 

Member  of  American  Gas  Institute 
Member  of  American  Society  of  Mechanical  Engineers 


247    ILLUSTRATIOXS 


NEW    YORK: 

D.    VAN   NOSTRAND    COMPANY 

23  MURRAY  AND  27  WARREN  STREETS 
LONDON: 

CROSBY  LOCKWOOD   &   SON 

1910 


Copyright,  1010 

BY 
D.   VAN   NOSTRAND  COMPANY 


iThc  Scientific  JJrcss 
Robert  Bnimmonb  anli  Compauu 


PREFACE 


IN  placing  before  the  American  industrial  world  the  following  chapters,  the 
author  desires  to  make  clear  his  position. 

Where  he  refers  to  or  describes  processes,  apparatus  or  inventions  operating 
under  patents  or  otherwise,  he  has  done  so  merely  to  explain  the  predominant 
systems  and  illustrate  the  respective  types  of  apparatus  and  appliances  which  are 
in  successful  operation  at  the  present  time. 

He  in  no  wise  specially  recommends  any  apparatus  or  instrument  herein  described 
or  referred  to,  but  places  before  the  reader  its  description,  method  of  operation,  or 
other  data  for  the  purpose  of  giving  information  and  drawing  comparisons.  To  do 
so,  it  was  necessary  to  select  from  the  great  variety  of  apparatus  at  present  manu- 
factured, certain  examples  which  might  reasonably  be  assumed  as  typical  of  the 
«lass  which  they  respectively  represent,  and  which,  as  nearly  as  possible,  embody 
and  emphasize  the  characteristics  of  that  class. 

It  is  with  the  urgent  desire  to  maintain  an  impartial  attitude  and  to  narrate  as 
accurately  as  possible,  without  prejudice  or  undue  influence,  the  various  features  of 
gas  engineering  at  present  in  vogue  in  the  industrial  field,  that  the  author  has  written 
the  following  volume. 

It  has  been  his  desire  to,  as  nearly  as  possible,  avoid  strictly  scientific  and 
technical  language,  to  put  before  his  readers  in  simple  style  producer-gas  engineering 
practice,  as  applied  to  everyday  operations  upon  a  practical  and  commercial  basis, 
omitting  any  theorizing  and  laboratory  results  unsuited  to  actual  commercial  and 
manufacturing  conditions. 

It  is  his  desire  to  make  this  handbook  readable  to  the  engineer,  operator,  and 
promoter,  and  to  this  end  he  has  attempted  to  present  in  simple  and  elementary 
style  the  various  subjects  herein  contained. 

Trusting  that  the  work  will  be  accepted  in  the  spirit  here  outlined,  he  sends  it 
out  for  the  consideration  of  the  American  industrial  world. 

NISBET  LATTA. 

NEW  YORK,  January,  1910. 

ill 


CONTENTS 


CHAPTER  I. — PRODUCER  OPERATION 

PAGE 

Fuel  bed 1 

Heat  recovery 3 

Efficiency  of  producers , 4 

Losses  in  producer 6 

Clinker 7 

Temperature 8 

Reactions 9 

Endothermic  agents 12 

Test  flame 13 

Steam  cooling 15 

Reduction  of  CO2  to  CO • 21 

Connections 24 

Sizes 24 

Weights 25 

Producer  shell 26 

Continuity 26 

Fire-brick  linings 26 

Repairs  and  maintenance 27 

Shell  insulation 27 

Grouting 28 

Cements  for  repairing 28 

Rating 30 

Load  factor 31 

Up-and-down  draft  types 31 

Suction  and  pressure  types 32 

Water  seal  producers 33 

Steam  supply 33 

Steam  temperature 35 

St.  John  recording  steam  meter 36 

Sargent  steam  and  air  meter 39 

Grates  for  producers 41 

CHAPTER  II. — CLEANING  THE  GAS 

General  conditions 49 

Dry  scrubbers 51 

Removing  dust  from  furnace  gas 53 

Dust  determination 55 

Influence  of  dust 59 

Thiesen  centrifugal  gas  washer 59 

Saaler  washer 60 

v 


vi  CONTENTS 


PAGE 


Latta  heavy  duty  centrifugal  separator 61 

Fixed  centrifugal  separators 63 

Reversed  current  separators 64 

Condensing  blast  moisture 64 

Tower  scrubbers 66 

Sprays 68 

Scrubber  water 70 

Wash  box  and  seals 71 

Receiver  tanks 71 

Tar  extractors 73 

Comparison  of  tar  extractors 73 

Stationary  tar  extractors 75 

P.  &  A.  baffling  tar  extractors 77 

Centrifugal  tar  extractor 78 

Gas-engine  gas  requirements 80 

Sulphur  in  engine  gas 82 

CHAPTER  III. — WORKS  DETAILS 

Vaporizers  and  economizers 83 

Charging  producers 86 

Safety  devices 86 

Insurance  requirements 88 

Gas  explosions 89 

Gas  asphyxiation 91 

Oxygen  administration 91 

CHAPTER  IV. — PRODUCER  TYPES 

Down-draft  producers 93 

The  Wood  system 94 

The  Tait  system 96 

Operation  of  the  Tait  producer .  104 

Starting  up 105 

Troubles 106 

Back  firing 106 

Pre-ignitions 106 

Loomis-Pettibone  producer -  108 

Apparatus 

Operation •  •  112 

Uses  of  a  producer  gas 115 

Staub  suction  gas-producer 

The  Morgan  producer 

Westinghouse  double  zone  producer 118 

The  Herrick  producer 

Smith  lignite  producer 

Lignite  suction  producers 126 

Wood-fuel  suction  producer 

Powdered  fuel  producers 

The  Hirt  powdered  fuel  producer 

The  Marconet  powdered  fuel  producer 138 


CONTENTS  vii 
CHAPTER  V. — MOVING  GASES 

PAGE 

Rotary  hot  gas  blower 141 

Suction  producer  exhausters 142 

Blowers  and  fans  compared 145 

Testing  blast  for  velocity  and  pressure 145 

Volume  test  by  Pitot  tubes 149 

High-pressure  blowers 150 

Venturi  meter 153 

Data  on  moving  air 153 

Influence  of  temperature 154 

Tables  useful  in  calculations 155 


CHAPTER  VI. — SOLID  FUELS 

Coal  and  its  classification 162 

Producer  fuel 165 

Gas  coal 165 

Tar  yield  from  gas  coal 167 

Coal  analysis 168 

Sulphur 169 

Calculating  heat  value 169 

Moisture  in  boiler  coal 170 

Clinkering  properties  of  coal ' 170 

Purchasing  of  coal 

Sampling  coal 174 

Storage  of  coal 176 

Coal  and  lignite  gas  compared 177 

Producer  fuel  tests , 177 

Clinkering  test 178 

Composition  of  fuels  and  their  gases 182 

Gas-house  coke  as  producer  fuel 186 

Tan  bark  for  making  producer  gas 186 

By-product  coke-oven  results 187 

Fuel  data  .  ,  .187 


CHAPTER  VII. — PHYSICAL  PROPERTIES  OF  GASES 

General  properties  of  gases 190 

Properties  of  vapors 195 

General  laws  of  gases 197 

Ignition  temperature  of  gases 205 

Calorific  power  of  gases 207 

Specific  heats  of  gases  and  solids 211 

Weight  and  volume  tables 214 

CHAPTER  VIII. — CHEMICAL  PROPERTIES  OF  GASES 

Hydrogen 217 

Carbon  monoxide 218 

Marsh  gas,  methane 218 

Ethylene 219 

Acetylene •. 219 

Natural  gas 219 


viii  CONTENTS 

PAGE 

Nitrogen 220 

Carbon  dioxide 220 

Oxygen 220 

Steam 220 

Tarry  matter 220 

The  air 220 

Composition  of  industrial  gases 221 

Producer  gas  analyses 223 

Bituminous  producer  gas 225 

Anthracite  producer  gas 227 

Power  gas 229 

Coal  gas  mixed  with  producer  gas 231 

Water  gas 232 

Blast-furnace  gas 233 

Blast-furnace  gas  power 233 

Carbon  dioxide  in  gas 234 

Tables  on  vapor  tension,  solubility,  etc 236 

CHAPTER  IX. — GAS  ANALYSIS 

The  Orsat  apparatus 238 

The  Morehead  apparatus 242 

Carbon  dioxide  determination 249 

Tait  CO2  burette 249 

Uehling  gas  composimeter 251 

Sarco  CO2  recorder 254 

Wise  CO2  recorder 257 

CHAPTER  X. — GAS  POWER 

Development 260 

Quality  of  gas 261 

Pre-ignition  due  to  hydrogen 262 

Aqueous  vapor 262 

Operation  conditions 264 

Coke  oven  gas 265 

Blast-furnace  gas 266 

Steam  and  producer  gas  tests 267 

Stand-by  losses 268 

CHAPTER  XI. — GAS  ENGINES 

General  details ; ....  270 

Foundations 272 

Exhaust  mufflers 272 

Ignition 274 

Starting 275 

Compression 275 

Cylinder  dimensions 276 

Cooling  water 280 

Anti-pulsators 281 

Lubrication 282 

Engine  tests 283 

Load  factors 284 

Utilizing  exhaust  gases 286 


CONTENTS  ix 

CHAPTER  XII. — INDUSTRIAL  GAS  APPLICATIONS 

PAGE 

Comparison  of  industrial  fuels 287 

Heat  recovery 288 

Forms  of  burners 291 

Ferrofix  brazing  head 292 

Machlet  burner 293 

Singeing  burner 294 

Soft  metal  melting  burner 294 

Blow  torch 295 

Pressure  blowers 297 

Forge  work 297 

Various  applications 298 

Gas  firing  of  steam  boilers 303 

The  Kirkwood  burner 303 

Boilers  using  waste  gases 307 

Boilers  fired  by  puddling  furnace  gas 308 

Rust  boiler  fired  by  producer  gas • 308 

Lester  boiler,  gas  fired 310 

CHAPTER  XIII. — FURNACES  AND  KILNS 

General  considerations 312 

Furnaces  fired  by  producer  gas  ..- 313 

Kilns  fired  by  producer  gas 317 

Brick  and  tile  manufacture 317 

The  Youngren  kiln 322 

The  Schmatolla  high-temperature  kiln 325 

CHAPTER  XIV. — BURNING  LIME  AND  CEMENT 

Calcination 328 

Lime  burning  with  natural  gas 329 

Vertical  lime  kilns 330 

Rotary  lime  kilns 332 

German  lime  kilns 333 

Cement  kilns 335 

Eldrecl  process  of  cement  clinkering 335 

Calcining  kilns 337 

Clinkering  kiln 338 

CHAPTER  XV. — PRE-HEATING  AIR 

Blast  stoves 344 

Sturtevant  air  pre-heater 346 

Green  air  pre-heater  349 

Triple  recuperation,  Queneau  system 352 

CHAPTER  XVI. — DOHERTY  COMBUSTION  ECONOMIZER 

Retort  bench  firing 354 

Chemical  reactions 360 

Advantages 361 

Operation  details 362 


x  CONTENTS 

CHAPTER  XVII. — COMBUSTION  IN  FURNACES 

PAGE 

Heat  and  temperature 364 

Velocity  of  flame  propagation 365 

Recuperation 365 

Temperature -. 366 

Ignition  temperature 372 

Nitrogen  as  affecting  combustion 373 

Air  supply  for  combustion 374 

Oxidizing  and  reducing  flames 377 

Progressive  combustion  stages 378 

Utilizing  sensible  heat 381 

Cases  of  generic  efficiency 380 

Furnaces — efficiency 379 

Heat-recuperation  furnaces 383 

Siemens'  regenerative  system 383 

Furnace  design 387 

Coal  and  gas  firing 390 

Reverberation  of  heat 390 

Dehydration  of  blast-furnace  gas 391 

Dehydration  of  water  gas 392 

Testing  explosive  mixtures 394 

Steel  melting  furnace  practice 394 


CHAPTER  XVIII. — HEAT:  TEMPERATURE,  RADIATION  AND  CONDUCTION 

Flame  temperature 396 

Specific  heats  of  gases 396 

Influence  of  kind  of  gas 400 

Melting  and  boiling  points  of  substances 401 

Industrial  operation  temperatures 406 

Annealing  and  tempering  heats 409 

Radiation  of  heat 41 1 

Conduction  of  heat 413 

Principles  of  heat  transfer 416 

Relative  heat  conductivity 423 

Expansion  due  to  heat 425 

Non-freezing  solutions 426 


CHAPTER  XIX. — HEAT  MEASUREMENTS:  PYROMETRY  AND  CALORIMETRY 

Bristol  pyrometers 428 

Seger  fire-clay  fusion  cones 435 

Heraeus-Le  Chatelier  pyrometer 439 

Fery  radiation  pyrometers 441 

Earnshaw  blue  glass  pyrometer 445 

Sargent  gas  calorimeter 446 

Junker  gas  calorimeter 448 

Doherty  gas  calorimeter 451 

Lucke- Junkers'  gas  calorimeter 454 

Parr  coal  calorimeter 454 

Sulphur  photometer 461 


CONTEXTS  xi 

CHAPTER  XX. — PIPES,  FLUES,  AND  CHIMNEYS 

PAGE 

Flow  of  gas  in  pipes 462 

Piping  data 464 

Friction  loss  in  pipes 467 

Capacity  of  flues 471 

Flow  of  natural  gas  in  pipes 472 

Flow  of  gas  under  high  pressures 474 

Chimneys 477 

Chimney  draft 478 

Weight  of  chimney  gases 479 

Smoke 480 

CHAPTER  XXI. — MATERIALS:  FIRE  CLAY,  MASONRY,  WEIGHTS  AND  ROPE 

Fire  clays 483 

Fire-brick  testing 484 

Fire-brick  joints 485 

Fire-brick  notes 486 

Masonry  construction :  Foundations 487 

Mortar -. 488 

Laying  brick 489 

Brick  tank  walls 489 

Requisites  for  good  brick 490 

Brickwork  measurement . , 491 

Stone  work 491 

Concrete  walls 494 

Weights  of  sheet  iron 496 

Rope :  Strength 499 

CHAPTER  XXII. — USEFUL  TABLES 

Circumference  and  area  of  circles 501 

Conversion  tables,  metric 502 

Heat  units 504 

Pressure  and  temperature  tables 505 

Density  conversion  tables 507 

Specific  gravity  of  substances 508 

Cost  of  erection  of  producer  plants 510 

APPENDIX. — OIL  FUEL  PRODUCER  GAS 

Jones  oil-gas  set 511 

Nix-Frost  gas  producer 513 

Amet-Ensign  gas  producer 515 

Gasifying  oil 518 

Oil  for  gas  making 518 

GLOSSARY  .  ,  .  521 


LIST  OF  ILLUSTRATIONS 


FIGURE  PAGE 

1.  Heat  Zones  in  Producers 9 

2.  Relation  of  Temperature  to  Combustion 10 

3.  The  Tait  Test  Flame,  Burner,  etc 14 

4.  Tait  Producer  Gas  Test.     (Section  of  Burner  on  Fig.  2) 16 

5.  Relation  of  Combustion  to  Temperature 18 

6.  Effect  of  Steam  on  Lowering  Heat  of  Fuel  Bed 19 

7.  Influence  of  Quantity  of  Steam  on  Heat  Absorbed 20 

8.  Influence  of  CO3  on  Temperature 21 

9.  Influence  of  Temperature  on  Specific  Heat 22 

10.  Conversion  of  Centigrade  and  Fahrenheit  Degrees 23 

11.  Section  of  the  St.  John  Seama  Meter 37 

12.  View  of  the  St.  John  Steam  Meter 38 

13.  The  Sargent  Steam  Meters 40 

14.  Grid  Type  Grate  Box  Air  Producer 42 

15.  Top  View  of  Grate 42 

16.  Section  of  Grate  Base 42 

17.  Shaking  Grates  Applied  to  Gas  Producer 44 

18.  Water-cooled  Repose  Grates 44 

19.  Water-cooled  Repose  Grates,  Area  Reduced  by  Blanks 45 

20.  Repose  Grates  for  Lignite  Fuel 47 

21.  Dry  Scrubber  used  by  the  Lackawanna  Steel  Co 51 

22.  Blast-furnace  Gas-cleaning  Plant 52 

23.  Sargent  Dust  Determinator,  Compact  Form 56 

24.  Sargent  Determinator,  complete 57 

25.  Test  for  Dust  and  Moisture 58 

26.  Thiesen  Centrifugal  Gas  Washer .- .- ; 60 

27.  Sections  of  Saaler  Gas  Washer  and  Vanes  on  Surface  of  Drum 60 

28.  Latta  Heavy  Duty  Washer 62 

29.  Gas  Power  Company  Washer • 63 

30.  Fixed  Centrifugal  Separator 63 

31.  Steam  Separator  used  as  Moisture  Remover 64 

32.  Examples  of  Baffling  Separation,  the  dust  or  moisture  being  deposited  by  the  reversal 

of  direction  of  flow 64 

33.  Tower  Scrubbers  in  Series 66 

34.  Tower  Scrubbers  in  Part  Section 67 

35.  Tower  Scrubbers  Filled  with  Coke  or  Excelsior 67 

36.  Film  Tower  Scrubber 67 

37.  Misting  Spray  Scrubber 67 

38.  Section  of  Misting  Spray  Scrubber 68 

39.  Water  Misting  Spray 68 

xiii 


xiv  LIST   OF   ILLUSTRATIONS 

FIGURE  PAGE 

40.  Spray  Nozzle 69 

41.  Another  Form  of  Spray  Nozzle 69 

42.  Umbrella  Spray  Nozzle 70 

43.  Baffling  Separator 71 

44.  Water  Seal 71 

45.  Receiver  Tank  and  Moisture  Collector 72 

46.  Filter  used  in  Testing  for  Tar 73 

47.  Fixed  Centrifugal  Tar  Extractor 76 

48.  Elevation  of  the  P.  &  A.  Tar  Extractor 77 

49.  Plan  of  P.  &  A.  Tar  Extractor  showing  connections 77 

50.  Tar  Extractor 78 

51.  Vertical  Section  of  Centrifugal  Tar  Extractor 79 

52.  Centrifugal  Tar  Separator 79 

53.  Location  of  Tar  Separator,  Plan  and  Elevation 80 

54.  Water  Vaporizers  on  Producer 84 

55.  Producer  Economizers 84 

56.  Powdered  Fuel  Producer  Economizer 85 

57.  Economizer  for  Bituminous  Producer 86 

58.  Coal  Car  ready  for  charging  Producer 87 

59.  Charging  a  Gas  Producer 87 

60.  Charging  a  Car  with  Coal 87 

61.  Suction  Gauge  Board 87 

62.  Screen  Preventing  Firing  back , 88 

63.  The  Vajen  Helmet— Cut-out  Section  of  Vajen  Helmet  . 90 

64.  Oxygen  Administration  Apparatus 91 

65.  Taylor  No.  7  Producer  with  Revolving  Bottom 95 

66.  Diagram  showing  Arrangement  of  the  Tait  Producer  System 99 

67.  Automatic  Regulation  Exhauster.     (No.  14  in  Diagram  of  System) 100 

68.  View  of  Previous  Illustration 1 01 

69.  Diagram  of  Heat  Distribution  with  Tait  Process 102 

70.  Another  Example  of  Heat  Distribution 103 

71.  Twin  Producer  Plant,  Loomis-Pettibone  System 109 

72.  Loomis-Pettibone  Gas- Producer  System 110 

73.  Space  occupied  by  Plant 114 

74.  Staub  Suction  Gas  Producer.     Typical  anthracite  suction  producer,  as  manufactured  by 

the  Power  and  Mining  Machinery  Company 116 

75.  The  Morgan  Continuous  Gas  Producer  with  George  Automatic  Feed 117 

76.  A  175  H.P.  Westinghouse  Double  Zone  Bituminous  Gas  Producer 119 

77.  Section  of  Westinghouse  Producer 1 20 

78.  The  Herrick  Generator  in  Half  Section 122 

79.  Tuyere  and  Steam  Blower  of  Fig.  75 122 

80.  Smith  Lignite  Producer 124 

81.  Air  and  Steam  Pre-heater 1 25 

82.  Lignite  Suction  Producer 1 27 

83.  Suction  Producer  for  Wood  Fuel 1 33 

84.  Hot  Gas  Exhauster 142 

85.  Eynon-Evans  Steam  Blower  and  Exhauster , 144 

86.  The  Korting  Injector  Blower 144 

87.  Water  Gauge  for  High  Pressure 148 

88.  Blast  Pressure  Recorder 

89.  Anemometer 

90.  Pitot  Tube  Arrangement,  showing  Location  of  Test  Pipe  for  Cupola  Blast  . 

91.  Arrangement  of  Tubes 1 

92.  Power  required  by  Pressure  Blowers 151 


LIST   OF    ILLUSTRATIONS  xv 

FIGURE  PAGE 

93.  Relation  of  Volume  to  Pressure 152 

94.  Brewster  High  Pressure  Blower 152 

!)5.  Crucible  Proximate  Coal  Test .' 168 

96.  Pounds  of  various  Coals  per  Horse-power 176 

97.  Combustion  Test  for  Coal 179 

98.  Relation  of  Richness  of  Coal  to  Rate  of  Combustion 179 

99.  Relation  of  B.T.U.  of  Coal  to  cu.ft.  per  Ib 180 

100.  Relation  of  B.T.U.  per  Pound  to  Producer  Efficiency 180 

101.  Richness  of  Coal  and  Power  Yield , 181 

102.  Relation  of  Combustion  Rate  to  Gas  Yield  per  Pound 181 

103.  Relation  of  Combustion  Velocity  to  Efficiency  of  Producer 182 

104.  Diagram  showing  the  loss  of  Fuel  in  Fuel  Gas  under  different  conditions 235 

105.  Relation  of  CO2  to  Heat  Loss 236 

106.  Forms  of  Orsat  Apparatus 238 

107.  The  U.  G.  I.  Form  of  Orsat  Apparatus 241 

108.  The  Morehead  Gas  Burette  in  use 243 

109.  Gas  Sample  Can 245 

1 10.  Suction  Pump  for  Gas  Sampling 248 

111.  Tait  CO,  Burette 250 

112.  Principles  of  the  Gas-Composimeter 251 

113.  Diagram  of  the  Uehling  Gas-Composimeter 252 

114.  The  Sarco  Automatic  CO2  Recorder 255 

115.  Section  of  the  Sarco  CO2  Recorder 256 

116.  Wise  Continuous  CO2  Indicator 258 

117.  Heat  Balance  of  Blast  Furnace  of  250  Tons  Daily  Capacity 266 

118.  Heat  Balance  of  a  By-product  Coke  Oven  of  200  Tons  Daily  Capacity 266 

118?.  Comparative  Heat  Utilization  of  Steam  and  Gas  Engines  and  Relation  of  Heat  Con- 
sumption and  Annual  Cost 267 

1 19.  Gas  Engine  Cycles 270 

120.  Combustion  Pressures 271 

121.  Comparison  of  Blast-furnace  Gas  and  Producer  Gas  .    . 271 

122.  Floor  Foundation 272 

123.  Masonry  Gas  Engine  Foundation 272 

124.  Gas  Engine  Exhaust  Mufflers 273 

125.  Niirnberg  Type  of  Water  Cushion  Exhaust 274 

126.  Relation  of  Cooling  Surface  to  Clearance  Volume 277 

127.  Influence  of  Altitude  on  Horsepower 285 

128.  Mixing  Burners  for  Hawley  Down-Draft  Kilns 288 

1 29.  Blast  Connection  for  Furnaces 290 

130.  Burner  Used  in  Oven  Furnace , 291 

131.  The  Ferrofix  Brazing  Head  and  Machlet  Burner  Tip 292 

132.  Special  Brazing  Burner 293 

133.  Ribbon  Singeing  Burner 294 

134.  Blast  Confectionery  Stove 295 

135.  Blast  Blow  Torch 296 

1 36.  Cyclone  Annular  Burner 296 

137.  Pressure  Blower  for  Gas 297 

138.  Muffle  Furnace  Using  City  Gas.     With  holder  pressure,  a  temperature  of  2000°  F.  was 

obtained,  which  was  raised  to  2500°  F.  by  blast  from  an  attached  fan 298 

139.  Water  Still 299 

140.  Producer  Gas  Heating  Furnace  for  Heating  Plates  for  Pressing  into  Shapes 299 

141.  Brazing  by  Producer  Gas 299 

142.  Producer  Gas-fired  Crucible  Furnaces  for  Heating  Brass  and  Aluminum.     Capacity, 

9  melts  per  10  hours 300 


xvi  LIST   OF   ILLUSTRATIONS 

FIGURE  PACE 

143.  Producer  Gas  Forge  Furnace.     Heats  14,500  -i-inch  bolts  in  10  hours 300 

144.  Producer  Gas-fired  Furnaces.     Case  Hardening,  Annealing  and  Core  Ovens .   301 

145.  Large  Producer  Gas-fired  Furnace  for  Heating  Steel  Ingots  up  to  5000  Ibs.     There  is 

no  flue  for  waste  gases  and  the  temperature  is  about  3000°  F 301 

146.  Galvanizing  with  Producer  Gas  Heat 302 

147.  Producer  Gas-fired  Annealing  Ovens.     Built   for  natural  gas  but   changed  over  to 

producer  gas 302 

148.  Producer  Gas-heated  Japanning  Ovens  Used  on   Sewing  Machine  Head.     They  are 

heated  to  500°  F.  in  20  minutes.     Natural  gas  had  been  used  previously 303 

149.  Kirkwood  Natural  Gas  Burner 304 

150.  Position  of  Burner  and  Fire-wall  in  Furnace 305 

151.  Front  of  Fire-wall 305 

152.  Kirkwood  Burners  Applied  to  Water  Tube  Boilers  without  Disturbing  the  Stoker 305 

153.  Gas-fired  Water  Tube  Boiler 306 

154.  Another  Gas-fired  Water  Tube  Boiler 306 

155.  The  Sipp  Gas-fired  Steam  Boiler 306 

156.  Rust  Boiler  Fired  with  Producer  Gas 309 

157.  Producer   Gas-fired   Metallurgical   Furnace.     The   pre-heated   air   is   admitted   under 

pressure 314 

158.  A  60-inch  Schwartz  Gas-fired  Furnace 314 

159.  Gas  Connections  to  Schwartz  Furnace 315 

160.  Fire  Tile  Lining  of  Furnace 316 

161.  Schwartz    Furnaces    of   45    Tons    Capacity    per   day   at    the    Plant    of   the   Magnus 

Metal  Co 316 

162.  Morgan  Producer  and  Furnace  for  Heating  Billets  30  ft.  long 317 

163.  Brick  Plant  Heated  by  Producer  Gas.     Arrangement  and  connections 320 

164.  Brick  Kiln  with  Mechanical  Draft 321 

165.  Arrangement  of  Pre-heated  Air  Flue 322 

166.  Diagram  Plan  of  Youngren  Continuous  Producer-fired  Brick  Kiln 323 

167.  The  Schmatolla  High  Temperature  Ceramic  Kiln 326 

168.  Section  of  the  Duff  Kiln— Plan  of  Duff  Kiln  Plant 331 

169.  Typical  Shaft  Lime  Kiln  showing  Runway  for  Charging  Limestone 331 

170.  Producer-fired  Rotary  Lime  Kiln 332 

171.  Rotary  Kiln  Plant  of  the  New  England  Lime  Co.  under  Construction 333 

172.  Vertical  and  Horizontal  Sections  of  a  German  Gas-fired  Lime  Kiln 333 

173.  Section  showing  Pressure-air  Nozzles  (a) 334 

174.  View  of  German  Gas-fired  Lime  Kiln 334 

175.  Gas-fired  Rotary  Cement  Kiln 335 

176.  Rotary  Cement  Kiln  Designed  for  Highest  Thermal  Efficiency 341 

177.  Section  of  Blast  Pre-heater  Pipe 345 

178.  Longitudinal  Vertical  Section  of  U-pipe  Hot-blast  Pre-heater 345 

179.  U-pipe  Hot-blast  Stove 34G 

180.  Sturtevant  Air  Pre-heater  Plant  (Elevation,  Plan  and  Cross-section) 347 

181.  Air  Pipes  and  Scrapers  to  Remove  Flue  Dust 34$ 

182.  Passage  of  Gases  among  Straight  Rows  and  Staggered  Pipes 349 

183.  The  Green  Fuel  Economizer  in  Poughkeepsie  (N.  Y.)  Gas  Works,  where  it  is  saving 

25%  of  the  boiler  fuel .350 

184.  Air  Pre-heater  on  Water-gas  Machine 351 

185.  Air  Pipes  and  Scrapers  on  Green  Pre-heater 352 

186.  Recuperation  of  Primary  Air,  Secondary  Air,  and  Gas — Queneau  System 352 

187.  Gas  Bench  Producer  adapted  to  Flue-gas  Blast — Doherty  System 355 

188.  Recuperators  of  Doherty  Benches — Bench  Furnace  in  Process  of  Construction.     Large 

blocks  are  used  instead  of  brick 358 

189.  Flame  Temperatures  as  influenced  by  excess  Air 307 


LIST   OF    ILLUSTRATIONS  xvii 

FIGURE  PAGE 

190.  Relation  of  Pounds  of  Dry  Coal  Burned  per  Hour  per  sq.ft.  of  Grate  Surface  to  Resulting 

Combustion  Temperature 369 

191.  Relation  of  10,000  B.T.U.'s  evolved  per  sq.ft.  of  Grate  Surface  per  Hour  to  Resulting 

Temperature 369 

192.  Composition  of  Flue  Gas  compared  with  Furnace  Temperature.     Curve  No.   1=O2; 

Curve  No.  2  =  CO2;  Curve  No.  3  =  CO 371 

193.  Composition  of  Burned  Gas  in  rear  of  Combustion  Chamber  at  Temperatures  Given: 

Curve  No.  1=CO2,  O2,  and  CO;  Curve  No.  2=-O2;  Curve  No.  3  =  CO2;  Curve  No.  4  = 
CO.     The  samples  of  gas  were  taken  through  water-jacketed  sampling  tubes 371 

194.  Influence  of  Rate  of  Combustion  and  Dryness  of  Fuel  upon  Temperature  (U.  S.  Geol. 

Sur.  Report) 372 

195.  Proportion  of  Losses  Due  to  Imperfect  Combustion  or  Due  to  CO  in  Flue  Gas 372 

196.  Horizontal  and  Vertical  Cross-section  of  a  Siemens  Regenerative  Furnace  as  Used  at 

Freiburg 384 

197.  Vertical  Cross-section  through  Entrance  Port  of  Siemens  Furnace 385 

198.  Horizontal  Section  through  Flues  under  Checkers  and  through  Checker-Brick  Chambers  385 

199.  Sections  of  Siemens  Furnace  showing  Flues  and  Reversing  Valves 386 

200.  Another  Arrangement  of  Reversing  Flues  and  Valves 387 

201.  Reversing  Valve  for  Siemens  Furnace 389 

202.  Illustrating  the  Reflection  or  Reverberation  of  Heat 391 

203.  Refrigerating  Plant  for  Condensing  Moisture  in  Blast  Air 393 

204.  Safety  Device  in  Testing  Gas  when  Filling  new  Holders  or  Mains 394 

205.  Couple  of  Bristol  Electric  Pyrometer 429 

206.  Bristol  Pyrometer  Connections 429 

207.  Connection  C  of  Fig.  206 429 

208.  Temperature  Correction  Device 430 

209.  Position  of  Fig.  208  in  the  Circuit 430 

210.  Arrangement  for  Testing  Molten  Metals 431 

211.  Position  of  Pyrometer  in  Furnace 432 

212.  Bristol  Secondary  Electric  Pyrometer  complete » 434 

213.  Section  of  Pyrometer  Fire  Tube  containing  Thermo-electric  Couple 440 

214.  Complete  Heraeus-Le  Chatelier  Pyrometer  Outfit 440 

215.  Section  of  F£ry  Radiation  Pyrometer 441 

216.  Fery  Radiation  Pyrometer  in  Protected  Case  Sighted  into  Fire-clay  Test  Hole 442 

217.  Self-leveling  Indicator  for  Fery  Pyrometer 442 

218.  Scale  of  Fig.  218   442 

219.  Taking  Temperature  of  a  Gas  Retort  by  Fery  Pyrometer 443 

220.  Earnshaw  Absorption  Pyrometer  (End  Elevation) 445 

221.  Earnshaw  Absorption  Pyrometer  (Side  Elevation) 445 

222.  Glass  Disc  Carriers  for  Fig.  221 446 

223.  Section  of  Sargent  Gas  Calorimeter 447 

224.  Sargent  Gas  Calorimeter  Complete 447 

225.  Collector  for  Testing  Dusty  Gases 448 

226.  General  Arrangement  of  Junker  Calorimeter 449 

227.  Section  of  Pressure  Regulator  C 449 

228.  Junker  Gas  Calorimeter  in  Section  and  Elevation  and  Pressure  Regulators 450 

229.  Burner  of  Junker  Gas  Calorimeter 450 

230.  The  Doherty  Gas  Calorimeter 453 

231.  The  Lucke  Continuous  Record  Gas  Calorimeter 454 

232.  Section  of  Parr  Coal  Calorimeter 455 

233.  Cartridge  Ignited  by  Hot  Wire 455 

234.  Cartridge  Electrically  Ignited 455 

235.  Parr  Calorimeter,  Complete 456 

236.  Resistance  for  Electric  Circuit .   456 


xviii  LIST   OF   ILLUSTRATIONS 

FIGURE  PAGE 

237.  Total  Carbon  Apparatus  for  Parr  Test 460 

238.  Sulphur  Determination  Apparatus  for  Parr  Test 460 

239.  Relation  of  Mains  to  Branches 466 

240.  Barrus  Draft  Gage 479 

241.  Fire-brick  Shapes 486 

242.  Circular  Functions 502 

243.  Jones  Oil-gas  Producer  Set,  with  and  without  Checker  Brick  Filling 512 

244.  The  Nix-Frost  Crude-oil  Suction  Gas  Producer 513 

245.  Amet-Ensign  Oil-gas  Producer 515 

246.  Battery  of  Amet-Ensign  Producer 516 

247.  Section  of  Amet-Ensign  Producer,  showing  Oil-vaporizing  Plate 517 


PRODUCER  GAS  PRACTICE 


CHAPTER  I 
PRODUCER  OPERATION 

THE  general  theory  of  gas  producers  and  the  historical  as  well  as  typical  designs 
have  been  already  fully  treated  in  other  works,  so  that  they  will  not  be  dwelt  on 
here.  Rather  will  the  practical  features  of  producer  design  and  operation  be  enlarged 
upon  as  being  more  in  the  province  of  this  handbook.  The  operation  of  the  several 
pieces  of  apparatus  employed  in  making  producer  gas  will  first  be  taken  up,  to  be 
followed  by  descriptions  of  producers  at  present  in  general  operation  in  this  country. 

In  spite  of  the  vast  number  of  gas  producers  now  in  the  market,  and  the  dif- 
ferent methods  of  operation,  the  fact  remains  that  there  is  but  one  common  factor 
of  importance,  and  upon  this  hinges  the  successful  operation  of  the  producer,  regard- 
less of  its  other  accessories,  methods  or  attributes.  This  may  be  briefly  summarized 
under  the  term  of  "  stoking  "  or  the  maintenance  of  a  compact  fire  bed. 

Fuel  Bed. — To  complete  the  gasification  of  coal  in  a  producer  it  is  necessary 
that  all  the  air  admitted  into  the  producer  be  brought  into  contact  with  incandescent 
carbon,  and  to  this  end  the  one  feature  to  be  poignantly  emphasized  is  to  maintain 
the  fire  bed  compact. 

That  is  to  say,  either  by  stoking,  hand,  mechanical  or  in  "  compressed  gas  shots," 
the  condition  of  the  bed  must  be  maintained  homogeneous  and  free  from  rivers, 
chimneys  or  channels,  through  which  air  or  steam  may  pass  undissociated  to  the 
top  or  )>ottom  of  the  fire,  depending  upon  the  direction  of  draft. 

To  a  lack  of  attention  to  this  principle  is  due  90%  of  the  troubles  met  with 
in  the  maintenance  of  constant  service  and  a  continuity  of  a  fixed  or  uniform  gas 
of  constant  value. 

The  fire  should  be  barred  down,  stoked,  coaled,  or  otherwise  made  compact 
at  such  intervals,  depending  upon  conditions  of  fuel  demand,  capacity,  etc.,  as  will 
absolutely  ensure  this  condition.  For,  failing  in  such  attention,  it  may  be  assured 
that  two  things  will  happen.  First,  that  the  air  or  steam  passing  through  incom- 
pletely dissociated  will  form  a  gas  high  in  carbonic  acid  and  free  oxygen  and  of  a 


2  GAS   PRODUCERS 

lean  and  irregular  character.  Second,  the  free  oxygen  passing  through  the  fire  and 
meeting  the  finished  gas  will  produce  secondary  combustion  on  top  of  the  fire  or 
distillation  zone  and  consume  the  gas  actually  manufactured  within  the  producer, 
with  a  tremendous  resultant  loss  in  both  gas  and  through  radiation,  besides  having 
an  extremely  destructive  effect  upon  the  producer  itself. 

It  may  be  noted,  therefore,  that  when  an  up-draft  producer  is  burning  very 
hot  on  top,  as  indicated  either  by  looking  through  the  sto king-holes,  side  cocks,  or 
by  the  use  of  a  pyrometer,  that  it  is  an  invariable  sign  that  air  is  sifting  through 
the  fuel  bed,  which  has  become  "  honey-combed  "  or  has  had  a  fissure  broken 
through,  and  that  this  air  is  causing  combustion  of  the  gas  inside  of  the  producer. 

This  is  particularly  frequent  where  an  exceedingly  thin  fuel  bed  is  run  and 
also  with  fuels  possessing  large  voids,  such  as  coke  and  the  largest  size  of  anthracite 
or  run  of  mine  coal.  These  coals  require  closer  attention  in  order  to  maintain  uni- 
form gas  and  constant  conditions  of  operation. 

Anthracite  suction  producers  using  pea  or  nut  coal  are  found  to  run  most 
efficiently  upon  a  fuel  bed  approximating  30  inches  in  depth.  The  depth  of  a  fuel 
bed  must,  however,  necessarily  increase  with  the  size  of  the  fuel  and  its  consequent 
voids. 

For  bituminous  fuels  however  a  4-ft.  depth  may  be  said  to  constitute  a  practical 
maximum,  the  best  results  being  found  at  this  depth,  while  a  greater  depth  renders 
stoking  extremely  difficult. 

Coke  may  get  under  some  conditions  a  foot  deeper  by  reason  of  its  light  weight 
and  small  tendency  to  bed  or  pack.  For  this  same  reason,  together  with  its  large 
voids,  coke  should  be  crushed  to  the  size  of  -a  nut  coal  mesh  before  being  used  in 
the  producer. 

The  producer  fire  should  be  examined  at  intervals,  never  exceeding  one-half 
hour  in  length,  for  from  its  color  and  degree  of  temperature  the  condition  of  opera- 
tion must  be  regulated.  One  of  the  dangers  of  mechanical  stokers  arises  from  the 
fact  that  there  is  a  tendency  on  the  part  of  the  inspector  to  be  too  long  between 
observations  or  inspections. 

There  can  be  no  fixed  rule  for  regularity  of  interval  or  periodicity  in  stoking  of 
coal  in  producer  work,  especially  of  an  arbitrary  nature.  The  items  to  be  observed 
are  these: 

The  producer  should  be  coaled  at  sufficient  intervals  to  maintain  a  constant 
depth  of  fuel.  This  depth  depending  upon  the  size,  type  of  machine,  nature  of 
load  and  load  factor,  and  class  and  quality  of  fuel. 

The  stoking  or  poking  of  the  producer  should  be  at  sufficient  intervals  to  keep 
the  fuel  bed  absolutely  compact. 

The  cleaning  of  the  producer  should  be  at  such  intervals  as  shall  remove  from 
the  fire  the  objectionable  amount  of  clinker  or  ash,  and  the  intervals  must  be  deter- 
mined of  necessity  from  the  character  of  the  fuel,  nature  of  the  load,  and  the  relative 
capacity  of  the  machine. 

Great  care  should  be  observed  in  both  barring  down  and  removing  clinker, 
to  preserve  the  linings  from  any  unnecessary  erosion  or  violence.  Any  carelessness 
in  this  operation  will  reduce  the  life  of  the  lining  75%  or  80%. 

Where  clinkers  are  severe  they  may  be  removed  by  running  up  the  heat  of 


PRODUCER    OPERATION  3 

the  apparatus,  i.e.,  by  increasing  the  draft  and  cutting  off  the  endothermic  agent, 
even  where  it  is  necessary  to  exhaust  the  resultant  gas  through  the  purge  pipe. 

Clinkers  thus  softened  may  he  more  readily  barred  down.  Care  should  also 
be  taken  to  slowly  work  the  clinkers  out  of  the  ash  bed,  or,  as  this  is  generally  termed 
by  workmen  "  sneak  them,"  for  if  withdrawn  too  rapdily  or  carelessly  a  quantity 
of  good  fuel  will  be  drawn  with  them  and  lost. 

The  regulation  of  the  producer  depends  more  particularly  upon  the  use  and 
admission  of  the  endothermic  agent.  Where  flue  or  exhaust  gases  are  used  for 
this  purpose  its  satisfactory  balance  will  be  found  to  obtain  automatically;  that 
is  to  say,  that  the  proportion  of  exhaust  gases  remaining  maintains  an  equal  ratio 
with  the  demand  or  withdrawal  from  the  producer,  the  process  being  that  of  a  cycle 
and  it  is  merely  necessary  to  establish  such  proportion  to  have  it  automatically 
maintained. 

For  the  use  of  steam  or  moisture,  however,  the  process  is  more  complicated 
and  requires  more  constant  attention.  The  amount  increases  directly  with  the 
load  or  demand  and  conversely  decreases.  It  is  the  custom  of  the  writer  to  admit 
just  sufficient  amount  of  the  endothermic  agent  to  maintain  the  clinkers  in  a  tract- 
able state  and  to  preserve  the  lining  of  the  producer  from  excessive  heat. 

This  point  can  be  determined  only  through  experiment,  and  the  observation 
of  the  heat,  the  color  of  which  will  soon  be  learned  by  the  operator.  In  other  words,. 
it  seems  expedient  to  run  a  producer  as  hot  as  is  possible  without  the  formation 
of  excessive  clinker  or  destruction  of  the  linings.  Usually  the  white  lights  visible 
in  the  fire  and  around  the  linings  at  high  temperature  mark  the  danger  signals, 
and  the  heat  should  be  maintained  just  short  of  their  appearance. 

Heat  Recovery. — Preheating  of  the  primary  air,  as  well  as  the  secondary  air 
in  producer  work,  is  of  prime  importance  where  such  heat  is  recuperated  from 
waste  heat.  It  would  at  first  appear  incompatible  to  add  sensible  heat  to  the  fire 
of  the  producer,  inasmuch  as  the  total  producer  reactions  are  so  strongly  exothermic 
as  to  require  some  endothermic  agent,  such  as  steam  or  CO2  for  the  regulation  of 
the  fire  bed  temperature.  Further  study  however  will  show  that  where  this  heat 
is  added  a  larger  portion  of  the  endothermic  agent  may  be  used  and  distilled  or 
dissociated,  and  this  increase  may  be  said  to  transform  the  sensible  heat  restored 
to  the  producer  into  the  latent  heat  of  a  potential  gas,  thereby  greatly  increasing 
the  volume  of  potential  gas  given  off  by  the  producer;  or,  in  other  words,  increas- 
ing the  manufacture  of  potential  gas  per  unit  of  fuel,  the  function  of  the  sensible 
heat  restored  through  the  form  of  primary  air  recuperation  is  almost  identical  with 
that  of  the  sensible  heat  evolved  from  the  fuel  itself. 

As  has  been  stated  elsewhere,  one  chief  difficulty  with  water  seal  producers 
is  the  inability  to  regulate  the  depth  of  the  fire  bed.  This  difficulty  varies  between 
two  extremes.  First,  an  excess  of  depth,  which  tends  to  make  the  stoking  of  the 
fire  mechanically  impracticable.  Second,  a  deficiency  of  depth  which  causes  a 
channeling  of  the  bed  and  an  increase  of  CO2  from  (a)  a  combustion  of  CO  to  CO2 
within  the  producer  on  top  of  the  fire,  due  to  the  passage  of  undissociated  air  or 
free  oxygen  through  the  fire  in  chimneys  or  channels;  (6)  lessening  of  the  time  con- 
tact in  passage  of  gases  through  the  fire,  and  hence  for  the  consequent  secondary 
reaction  of  CO2  to  CO;  (c)  a  less  distillation  due  to  reduction  of  heat  and  a  depth 


4  GAS   PRODUCERS     • 

of  distillation  zone,  and  moreover  an  intense  heat  localization,  due  to  the  condition 
(a)  and  a  consequent  destruction  of  the  producer  linings,  and  the  fluxing  of  fusible 
ash,  forming  clinker. 

This  phenomenon  is  so  well  known  that  it  is  the  practice  in  operating  the 
soaking  pits  in  many  steel  mills  to  lower  the  fire  bed  for  the  purpose  of  increasing 
the  CC>2  and  thereby  obtaining  an  elongated  and  slow  combustion  gas  flame  within 
the  furnace  or  soaking  pit. 

It  will  be  manifest  that  this  condition  is  obtained  at  an  immense  expense  or 
waste  of  fuel,  and  where  such  an  arrangement  is  necessary  it  is  much  more  eco- 
nomical to  add  to  the  finished  gas  or  secondary  air  a  certain  percentage  of  flue  gas 
(from  3  to  12%,  depending  upon  the  temperature,  a  larger  amount  being  required 
for  higher  temperatures  of  flue  gases),  and  thereby  obtaining  the  retarded  or  vol- 
uminous flame.  The  principle  involved  in  this  is  described  elsewrhere  at  greater 
length. 

The  experiments  of  Euchene  go  to  show  that  22.3%  of  the  heat  value  of  the 
fuel  is  used  to  bring  up  the  sensible  temperature  of  effluent  gases.  In  many  instances 
a  certain  portion  of  this  temperature  is  recuperated  in  the  manufacture  of  steam 
and  through  its  medium  returned  to  the  producer.  In  any  event,  however,  the 
importance  of  direct  connection  between  the  producer  and  the  furnace  will  be  obvious, 
as  well  as  the  insulation  of  the  connection  which  is  best  accomplished  by  lining  with 
fire  brick,  the  fire  brick  being  separated  from  the  steel  shell  in  the  manner  exactly 
identical  with  the  method  in  which  the  producer  itself  is  grouted.  In  connection 
with  the  above  Butterfield  states:  "  The  sensible  heat  of  the  effluent  gases  aver- 
ages from  1400  to  1500°  F.  under  ideal  conditions.  This  sensible  heat  absorbs 
theoretically  17.2%  of  the  total  heat  of  the  fuel  liberated,  or  about  2500  B.T.U. 
per  pound  of  carbon." 

Where  the  sensible  heat  of  the  gas  is  utilized  for  steam  generation,  as  is  usually 
•done  by  running  through  a  tubular  boiler,  such  admission  should  never  be  of  the 
"  down  draught  "  type,  but  the  gases  should  enter  at  the  bottom  of  the  boiler  or 
water  leg.  This  is  for  the  reason  that  the  hot  gases,  when  entering  at  the  steam 
chamber  or  dome  tend  to  burn  out  the  tube  sheet  or  crown  plate,  whereas,  when 
entering  at  the  water  leg,  the  tube  sheet  is  protected  by  its  water  content  and  the 
gases  are  considerably  cooled  before  reaching  the  crown  sheet;  moreover,  the  change 
of  temperature  is  more  gradual  in  the  tubes  themselves  with  less  resultant  movement. 

Efficiency  of  Producers. — The  thermal  efficiency  of  producers  for  transformation 
of  the  latent  heat  of  the  coal  into  a  potential  gas  for  fuel  purposes,  recovering  the 
losses  through  radiation,  ash,  jacket  water,  sensible  heat,  etc.,  average  for  multi- 
unit  down-draft  types  approximately  85%.  For  up-draft  types  on  bituminous  or 
lignite  coal  where  tar  is  extracted  (the  efficiency  varying  according  to  the  tar  and 
resinous  content  in  coal)  the  efficiency  is  approximately  60%.  For  down-draft 
apparatus  on  anthracite  coal  approximately  80%.  These  figures  vary  widely,  but 
give  some  approximation  of  the  usual  practice. 

In  the  use  of  lignite  and  low  grade  fuels  containing  a  high  moisture  element 
(approximately  say  18%  or  above),  by  the  heat  absorption  and  combustion  of 
which,  together  with  the  low  flame  temperature  (partly  due  to  a  high  neutral  ele- 
ment), an  extraneous  endothermic  agent  is  rendered  unnecessary. 


PRODUCER    OPERATION  5 

It  must  be  remembered  that  the  efficiency  of  the  apparatus  is  rendered  rela- 
tively lower  by  reason  of  the  fact  that  theoretically  some  17.2%  (see  Butterfield), 
and  practically  22.3%  (see  Euchene)  of  the  heat  units  of  the  fuel  is  absorbed  in 
raising  the  effluent  gases  to  their  temperature  of  exit,  together  with  the  robbing 
effect  of  the  aqueous  vapor  which  they  mechanically  entrain. 

Under  ordinary  conditions  a  portion  of  this  sensible  heat  is  recuperated,  either 
by  manufacture  of  steam  or  by  the  sensible  temperature  of  the  products  of  com- 
bustion, the  heat  being  returned  and  restored  through  one  or  the  other  of  these 
mediums. 

Where  there  is  no  endothermic  agent  required,  however,  the  sensible  tempera- 
ture of  the  effluent  gases  for  power  purposes  at  least  are  not  recuperated,  and  such 
temperature  becomes  a  total  loss. 

To  offset  to  some  extent  this  condition  it  will  be  manifest  that  the  fuels  named 
can  be  most  efficiently  gasified  in  (a)  an  up-draft  producer,  (6)  a  multi-unit  pro- 
ducer in  which  the  first  unit  is  up-draft,  and  the  second  down-draft,  the  flow  of  gas 
being  reversed  for  the  following  reasons: 

In  this  arrangement,  by  carrying  a  relatively  deep  fuel  bed  the  effluent  gases 
from  the  combustion,  dissociation,  and  distillation  zones  pass  upward  through  the 
green  coal  and  are  relieved  of  their  sensible  temperature  in  some  degree  in  a  partial 
heating  of  the  charge,  the  result  being  that  such  charge  is  gradually  brought  up  to 
the  point  of  ignition  before  it  reaches  the  combustion  zone  and  is  delivered  pre- 
driecl  through  the  agency  of  the  sensible  heat  thus  extracted. 

As  a  matter  of  fact  this  is  only  a  relatively  efficient  method  of  recuperation, 
inasmuch  as  the  green  charge  in  the  producer,  which  is  rich  in  moisture,  abstracts 
from  the  fire  a  certain  quantity  of  heat  through  conduction.  Howrever,  the  largest 
portion  of  this  pre-drying  or  pre-heating  comes  from  the  sensible  temperature  of 
the  gases  passing  through  it  on  their  escape  from  the  producer. 

The  above,  suggesting  the  pre-heating  of  fuel  by  the  up-draft  of  the  effluent 
gases,  embodies  to  an  extent  the  principle  of  "  reversed  currents  "  wrhich  is  most 
efficient  in  heat  transference  and  is  extensively  met  with  in  the  various  conditions 
presented  by  gas  manufacture. 

In"  other  words,  the  hottest  gas  is  brought  in  contact  with  the  hot  test  fuel, 
and  vice  versa,  the  gases  being  gradually  cooled  and  the  fuel  being  brought  up  by 
stages  to  the  point  of  ignition,  its  distillation  and  drying  being  meamvhile  secured. 

It  will  be  patent  that  in  the  use  of  lignite  or  low-grade  fuel,  as  herein  suggested, 
that  the  fuel  bed  should  be  maintained  say  twice  the  depth,  otherwise  carried  with 
ordinary  bituminous  coal.  Coking  coals  invariably  give  trouble  when  hopper  fed 
by  reason  of  their  tendency  to  coke  and  "hang";  they  are  therefore  best  handled 
by  some  mechanical  device. 

Theoretically,  in  the  gas  producer,  says  Butterfield,  just  one-half  the  air  is  required 
for  the  theoretical  combustion  per  pound  of  coal  in  the  direct-fired  furnace.  This 
does  not  cover  the  excess  actually  necessary  in  practical  operation.  Pure  carbon 
and  no  moisture  nor  hydrogen  being  considered,  the  reaction  wrould  be  as  follows: 
CO,  34.7%,  and  N2,  65.3%.  In  the  ideal  producer  under  theoretical  conditions 
30.6%  of  the  heat  is  liberated,  that  would  be  liberated  in  the  direct-fired  furnace. 

In  the  experiments  of  Euchene  one  pound  of  coke  evaporated  40%  of  its  weight 


6  GAS   PRODUCERS 

of  water,  said  water  being  from  the  ash  pan  of  the  producer.  By  this  evaporation 
67.6%  reacted  with  the  carbon;  32.4%  escaped  with  this  gas  undissociated  in  the 
form  of  aqueous  vapor. 

The  decomposition  of  water  into  its  elements  of  hydrogen  and  oxygen  has  a 
total  endothermic  action  of  3900  B.T.U.  per  pound.  One  pound  of  carbon  plus  71.75 
cu.ft.  of  air  equals  CO  with  a  total  exothermic  action  of  3930  B.T.U.  The  radiation 
loss  in  this  producer,  which  was  of  the  Siemen's  type,  as  noted  by  Euchene,  was  5.7%. 

The  highest  theoretical  efficiency  in  producer  operation  is  of  course  only  obtain- 
able under  conditions  of  by-product  recovery,  as  for  instance  of  sulphate  of  ammonia. 
This,  however,  is  not  warranted  under  installations  of  from  3000  to  4000  h.p.,  and  then 
of  course  it  is  limited  by  the  fuel  available  and  the  market  demand  for  the  product. 
Depreciation  is  extremely  heavy  on  this  class  of  apparatus,  especially  in  portions 
where  sulphuric  acid  is  used.  So  heavy  is  its  maintenance  that  it  must  be  considered 
as  one  of  the  primary  costs  of  operation. 

The  sensible  heat  of  producer  gas  is  of  importance  because  12  to  18%  of  the 
heat  value  of  the  coal  may  exist  in  this  form,  the  loss  of  which  is  only  a  question 
of  cooling  the  gas.  It  is  utilized  only  when  gases  reach  the  furnace  hot,  and  the 
hotter  the  gases  leave  the  producer,  the  greater  may  be  this  loss. 

Hotter  gases  result  from  carbonized  and  dry  fuels,  rapid  driving  and  dry  blast 
more  than  from  uncarbonized  and  wet  fuels  or  steam  air-blast.  The  temperatures 
of  escaping  gases,  of  course,  vary  considerably,  depending  upon  character  of  fuel 
and  rapidity  of  driving. 

With    coke,   say  between  900°   and   1800°   F. 

Soft  coals,  say  between  600°  and  1600°  F. 

With  anthracite  and  steam  jet  blower,  1100°  F.  is  a  frequent  temperature. 

Where  the  heat  from  the  exhaust  of  a  gas  engine  is  recovered,  about  10%  of 
its  thermal  value  may  be  used  in  raising  steam  in  exhaust  boilers,  where  a  pressure 
as  high  as  160  pounds  per  square  inch  has  been  attained. 

Losses  in  Producer. — The  following  table  shows  the  percentage  of  this  loss 
with  varying  proportions  of  ash  in  the  coal  and  varying  percentages  of  carbon  in 
the  ash  drawn  from  the  producer: 


PERCENTAGE  OF  TOTAL  HEAT  VALUE  LOST 


Percentage  of  ash  in  coal. 


5%  carbon  in  ashes . 
10% 
15% 
20% 
30% 
40% 
50% 
60% 
80% 


0.22 
0.46 
0.74 
1.04 
1.80 
2.80 
4.16 
6.20 
16.60 


0.40 

0.84 

1.33 

1.90 

3.20 

5.00 

7.50 

11.30 

30.00 


10 

0.60 
1.25 


.98 
.80 
.80 
.40 
.10 
16.60 
44.40 


1 

2. 
4. 
7. 
11 


13 

0.80 

1.66 

2.64 

3.75 

6.40 

10.00 

15.00 

22.50 

60.00 


16 

1.00 
2.11 
3.36 
4.76 

8.16 
12.70 
19.00 
28.60 
76.00 


20 

1.30 

2.80 

4.40 

6.25 

10.70 

16.60 

25.00 

37.50 

100.00 


It  is  found  that  even  with  sulphur  as  high  as  3%  and  ash  10%  it  is  still  quite 
possible  to  make  good  gas  without  interruption,  although  at  much  reduced  rate. 


PRODUCER   OPERATION  7 

It  is  found  that  the  total  loss  from  all  sources  in  the  gasification  of  fuel  in  a 
Morgan  type  gas  producer  under  fairly  good  conditions,  when  the  gas  is  used  cold  or 
when  its  sensible  heat  is  not  utilized,  ranges  between  20%  and  25%,  which  under 
very  bad  conditions  may  be  increased  to  50%.  It  is  claimed  that  this  loss,  under 
favorable  conditions,  using  the  gas  hot,  is  reduced  to  as  low  as  10%,  which  also 
includes  the  heat  of  the  steam  used  in  blowing.  This  fact  can  be  arrived  at  and 
proven  by  calculation  from  the  analysis  of  the  gas  taken  in  relation  to  the  original 
analysis  of  the  coal.  The  interested  student  of  this  subject  is  referred  to  the  work 
of  H.  H.  Campbell  on  the  Manufacture  of  Iron  and  Steel,  chapters  VIII  and  IX. 
In  his  elaborate  investigation  all  the  sensible  heat  of  the  gas  (namely,  14.4%)  was 
assumed  to  be  lost,  which  it  always  is  in  the  Siemens  regenerative  furnace.  There 
was  also  found  to  be  a  loss  by  carbon  in  ashes  of  2.1%  (which  is  excessive),  and 
by  radiation  and  conduction  5.1%,  making  a  total  of  21.6%  lost.  As  his  equip- 
ment was  much  inferior  to  the  best  modern  practice  in  several  respects,  and  as  there 
are  a  great  many  cases  where  fully  two-thirds  of  the  sensible  heat  of  the  gas  is  utilized, 
it  will  be  seen  that  the  unavoidable  loss  by  good  practice  in  all  heating  furnaces 
should  not  exceed: 

One-third  of  sensible  heat  of  gas  =  4. 7%  loss 

Carbon  in  ash =0.3% 

Radiation  from  producer =5.0% 

Total  amount  lost 10.0% 

The  total  grate  loss  of  fuel,  that  is  to  say,  of  the  combustible  charge,  should 
not  exceed  2£%. 

American  producers  will  average  a  loss  through  their  grates  of  5%,  while  cer- 
tain badly  designed  producers  have  run  as  high  as  32%. 

It  is  stated  by  F.  E.  Junge  that  in  Germany  where  low  grade  clinkering  fuels 
are  used,  that  is  to  say  fuels  high  in  fusible  ash,  that  clinkering  has  been  entirely 
eliminated  by  the  substitution  of  cast-iron  producers  with  water-cooled  walls.  To 
quote  Mr.  Junge:  "  The  cooling  effect  of  the  water  does  not  extend  very  far  inter- 
nally, only  far  enough  to  effect  the  layers  lying  at  the  extreme  outside.  The  influence 
on  the  combustive  process  is  therefore  inconsiderable  in  such  producers."  The 
loss  of  heat  is  due  to  radiation  from  producers  is  much  more  constant  than  is  gen- 
erally supposed,  and  when  it  is  taken  into  consideration  that  fire  brick  at  white 
heat  has  the  same  conductivity  as  cast  iron,  Mr.  Junge's  conclusions  may  be  worthy 
of  some  consideration  and  investigation. 

Clinker. — The  next  in  importance  to  consider  is  the  subject  of  clinker.  The 
formation  of  clinker  tends  to  reduce  the  available  area  of  the  fuel  bed,  and  not  only 
by  the  space  it  occupies  defacto,  but  also  by  acting  as  a  deflector  converts  the  pas- 
sage of  air  into  channels  and  increases  the  unit  duty  of  the  remaining  surface  of 
the  bed.  This  naturally  increases  the  heat  of  the  fuel  bed  by  concentrating  the 
draft  in  certain  defined  directions  and  also  by  certain  radiant  heat.  The  result  is 
that  where  a  clinker  is  started,  it  tends  to  form  other  or  more  clinker,  both  along 
the  lines  aforesaid,  and  by  the  direction,  reflection  and  concentration  of  a  more 
intense  heat. 


8  GAS   PRODUCERS 

It  may  therefore  be  put  down  as  a  postulate  that  clinker  should  be  maintained 
at  a  minimum,  if  not  entirely  obviated  (this  latter  being  very  nearly  impossible), 
and  all  coals  possessing  a  high  content  of  fusible  ash  should  be  discarded  as  a  pro- 
ducer fuel  in  shaft  or  furnace  type  producers,  more  especially  where  used  for  the 
generation  of  gas  for  engine  combustion. 

It  is  seen  therefore  that  the  formation  of  clinker,  which  is  the  accumulation 
of  the  fluxed  portion  of  fusible  ash,  tends  both  to  irregularity  of  gas  through  its 
agency  as  a  deflector  in  the  passage  of  the  gas,  and  also  through  the  intense  heat 
resultant  upon  the  concentration  of  this  draft  upon  certain  sections  of  the  fuel  bed. 
This  and  its  removal  form  a  most  deteriorating  influence  upon  the  lining  of  the 
producer  itself. 

It  naturally  follows  that  in  proper  practice  the  effort  should  be  to  form  no 
clinker,  which  may  be  done  in  one  or  two  ways. 

First,  by  keeping  the  fire  compact,  for  the  concentrated  blast  of  certain  section 
or  area  of  the  fuel  bed,  due  to  rivers  or  chimneys,  has  a  strong  tendency  to  flux 
the  fusible  ash,  with  resultant  clinker. 

Second,  The  coal  selected  should  be  as  low  as  possible  in  its  content  of  fusible  ash. 

Third,  The  fire  should  and  must  be  kept  as  nearly  as  possible  below  the  point 
of  fluxing  this  fusible  ash.  This  may  be  done  with  pressure  producers  by  moderat- 
ing the  blast,  but  in  suction  producers,  and  pressure  producers  as  well,  the  tem- 
perature may  be  tempered  or  moderated  by  running  a  fair  depth  of  fuel  and  applying 
the  proper  amount  of  steam  in  the  regular  process,  or  of  CO2  in  the  Tait  or 
Doherty  processes. 

In  most  or  many  of  the  lignites,  producers  depending  upon  the  fusing  of  clinker 
or  its  removal  in  condensed  form  (such  as  Smith  type)  are  usually  impractical,  for 
the  following  reasons,  namely: 

That  the  clinker  formed  by  such  fuels  is  unhomogeneous,  due  to  the  fact  that 
while  a  portion  of  the  ash  is  fusible,  a  large  portion  is  infusible,  the  latter  creating 
a  diluent  for  the  former,  hence  preventing  cohesion  and  rendering  it  difficult  to 
segregate  it  in  la/ge  masses. 

This  inability  to  complete  segregation  prevents  the  formation  of  clinker  in 
small  groups  of  particles  throughout  the  entire  fuel  bed  and  working  towards  the 
grate  with  considerable  disadvantage  to  satisfactory  operation. 

By  reason  of  the  above  conditions  the  extraction  of  clinker  from  the  generator 
through  segregation,  with  many  of  the  lignitic  fuels,  is  thoroughly  impractical. 

Temperature. — An  exact  mean  must  of  course  be  found  between  this  amount  of 
steam  and  an  excess,  which  tends,  both  through  the  cooling  of  the  fire  and  the  failure 
of  a  proper  temperature  for  re-combination  in  the  upper  zone,  and  through  an  excess 
of  the  dissociated  or  free  oxygen  to  form  an  excessive  amount  of  carbon  dioxide. 

Gas  is  usually  of  the  best  quality  when  the  top  of  the  fuel  bed  (assuming  an 
up-draft  producer)  is  dark  in  color,  a  dull  cherry  or  medium  orange.  When  it 
assumes  the  color  of  light  orange  with  white  lights,  it  is  almost  certain  that  some 
secondary  combustion  is  taking  place,  that  is  to  say,  the  fire,  being  insufficiently 
compact,  permits  air  to  pass  through  and  burn  the  gases  within  the  producer. 

White  heats  or  white  lights  in  the  bright  orange  heats  should  always  be  avoided 
in  producer  work,  being  an  invariable  sign  of  too  high  temperatures. 


PRODUCER   OPERATION  9 

It  is  assumed  by  practically  all  authorities  on  producers  that  the  reaction  of  air 
in  its  passage  through  the  producer  is  from  O  to  C02  with  a  reaction  of  C02  to  CO, 
in  the  following  zone.  Whether  this  is  true  or  not  the  author  is  unable  to  definitely 
state. 

It  is  of  course  impossible,  however,  to  burn  the  fuel  merely  to  CO,  or  in  the 
event  of  the  theory  aforesaid,  to  convert  all  of  the  C02  to  CO,  but  nevertheless  the 
C02  can  and  must  be  maintained  at  a  minimum. 

The  production  of  CO  is  accelerated  by  the  use  of  fine  fuel  of  a  fair  degree  of 
depth.  Large  lump  fuel  producing  greater  voids  must  have  this  depth  materially 
increased  to  compensate  for  the  time  factor  of  contact,  etc.,  or  to  produce  a  lesser 
velocity  in  the  passage  of  the  blast. 

Air  over  incandescent  carbon  is  supposed  to  produce  the  minimum  of  CO2  at 
about  1900°  F.,  and  it  is  therefore  evident  that  the  heat  of  the  producer  should  be 
maintained  well  over  this  point. 


FIG.  1. — Heat  Zones  in  Producers. 


An  analysis  of  Stockman,  illustrating  the  hot  and  cold  working  of  a  producer 
upon  an  identical  fuel,  shows  a  decrease  of  12%  in  volume  of  gas,  with  a  gain  of  20% 
in  the  heat  value  as  a  result  of  the  higher  temperature  of  combustion. 

Other  conditions  being  the  same,  the  temperature  of  a  producer  will  increase 
almost  directly  with  the  amount  of  fuel  gasified  in  a  unit  of  time.  This  of  course 
is  dependent  upon  the  air  supply  and  also  upon  the  nature  of  the  air,  which,  if 
pre-heated,  is  much  more  efficient.  This  however,  as  indicated  by  Stockman's 
experience,  means  increased  velocity  and  lessened  time  contact. 

Reactions. — The  following  are  the  chemical  equations  representing  the  principal 
changes  which  occur  in  the  formation  and  combustion  of  producer  gas. 

Formation  of  producer  gas  from  air  and  carbon: 

C  +  02  =  C02,    +97,600  calories 
C02+C   =2CO,   -38,800       " 
2C+02  =  2CO,    +58,800 

Reactions  between  steam  and  carbon: 

H20+C=  H2+CO,     -28,800  calories 
2H2O+C  =  2H2+CO2,    -18,800       " 


10 


GAS   PRODUCERS 


Reaction  between  steam  and  carbon  monoxide: 

H20+CO  =  CO2  +  H2,      + 10,000  calories 
C02  +  H2=CO  +H20,   -10,000 

Combustion  of  the  constituents  of  producer  gas: 

2CO+  02  =  2C02,    + 136,400  calories 
2H2+  O2  =  2H20,   +138,000 
CH4  +  2O2=C02,      +2H20,   +213,500  calories 
C2H4+302  =  2C02,    +2H2O,   +341,100 

Professor  Lewes  says:  "  M.  O.  Boudouard  has  found  that  at  1112°  F.  CO2+C 
yields  23%  carbonic  oxide,  and  1832°  F.  C02+C  yields  99.3%  carbonic  oxide,  so 
that  the  proportion  of  carbonic  acid  in  producer  gas  depends  upon  the  temperature 
of  the  fire  and  the  velocity  of  the  gas  through  it." 

'**%- 


FIG.  2. — Relation  of  Temperature  to  Combustion. 

In  a  discussion  of  producer  designs  in  his  work  on  Gas  Producers  (page  15) 
Horace  Allen  referred  to  the  reaction  of  CO  and  C02,  and  the  necessity  of  large 
surface  contact  for  its  efficient  completion,  says  as  follows: 

"From  this  it  would  appear  that  the  grate  area  should  be  considerably  less 
than  the  area  of  the  producer  in  the  zone  in  which  the  reduction  of  C02  is  effected. 
This  conclusion  is  confirmed  by  blast-furnace  practice,  the  walls  of  the  bosh  of  the 
furnace  rising  from  the  hearth,  where  the  blast  is  introduced  under  some  pounds 
per  square  inch  pressure,  not  being  carried  up  vertically  but  at  an  angle  of  about 
70°.  This  method  of  reducing  the  velocity  of  the  gases  rising  from  the  fire  by 


PRODUCER   OPERATION  11 

increasing  the  area  of  the  chamber  was  almost  universally  adopted  in  gas  producers 
designed  for  gasifying  coal  for  heating  metallurgical  furnaces,  etc.,  and  is  still  fol- 
lowed by  most  of  the  high-capacity  producers  of  the  day.  However,  it  is  a  notable 
feature  of  the  smaller  class  of  producer  now  employed  to  work  on  the  "  suction  " 
principle  that  the  walls  are  generally  carried  up  vertically  above  the  grate.  This 
is  probably  due  to  convenience  of  construction  combined  with  the  small  size  of  the 
apparatus,  but  the  producer  in  working  corrects  this,  owing  to  the  accumulation  of 
ash  and  clinker  round  the  grate." 

Whether  or  not  this  is  actually  the  case  is  doubtful.  Certainly  after  cleaning 
periods  there  must  be  an  interval  in  the  compensation  to  which  Mr.  Allen  refers, 
and  at  best  the  dependance  upon  ash  and  clinker  as  a  baffling  medium  would  seem 
inefficient.  The  question  is  at  least  well  worthy  of  the  attention  of  designing 
engineers. 

The  average  producer  shows  a  heat  cycle  about  as  follows: 

Assuming  12  kilos  of  carbon. 

C  +  O2  =  CO2,   +  97,600  calories 
CO2+C  =  2CO,  -38,800 
2  =  2CO,  +58,800 


As  a  matter  of  fact  probably  both  of  these  reactions  occur  in  the  shaft  producer, 
due  largely  to  variations  in  temperature,  as  the  tendency  of  carbon  is  to  act  directly 
to  CO  at  a  temperature  above  1000°  C. 

Again,  in  the  use  of  powdered  fuel  it  is  likely  that  the  reaction  is  direct  to  CO, 
the  heat  being  greater  and  conditions  more  uniform. 

Based  upon  the  above  the  shaft  producer  shows  approximately  the  following 
distribution  of  available  heat: 

70%  latent  heat  in  gas; 
20%  sensible  heat  in  gas; 

10%  loss  by  radiation  and  complete  combustion; 
within  the  producer. 


This  also  includes  the  heat  taken  from  the  producer  and  the  sensible  heat  of  the 
ash. 

The  heat  cycle  is  analyzed  by  Richards'  as  follows: 

Heating  power  of  the  coal  per  unit; 
Heating  power  of  the  gas  per  unit  of  coal; 
Calorific  losses  in  conversion. 

The  last  item  being  subdivided  as  follows: 

Loss  by  unburned  carbon  in  the  ashes; 
Sensible  heat  of  the  hot  gases  issuing; 

Heat  conducted  to  the  ground; 
Heat  radiated  to  the  air. 


12  GAS    PRODUCERS 

The  large  amount  of  the  total  available  heat,  which  is  represented  by  the  sen- 
sible heat  of  the  gases,  will  show  the  great  necessity  of  burning  the  gases  as  close  as 
possible  to  the  producer  and  at  the  highest  possible  temperature.  This  is  of  course 
merely  applicable  to  the  use  of  producer  gas  in  furnace  work,  and  does  not  apply 
to  power  where  it  is  necessary  that  the  gases  be  cooled  prior  to  their  entry  into  the 
engine. 

Ingalls,  in  his  work  on  "  The  Metallurgy  of  Zinc  and  Cadmium,"  page  280, 
states  as  follows:  "  The  oxidation  of  carbon  is  a  complicated  process.  It  begins 
at  the  moderately  low  temperature  of  400°  C.,  carbon  dioxide  being  formed  then 
as  the  chief  product,  whether  the  supply  of  air  be  large  or  small,  and  only  a  very 
little  carbon  monoxide  being  formed  therewith.  The  oxidation  becomes  more  active  if 
the  temperature  rises  to  700°  C.,  but  the  chief  product  is  still  carbon  dioxide,  although 
the  air  supply  be  deficient.  Even  under  that  circumstance,  which  in  so  far  as  the 
proportion  of  air  to  carbon  is  concerned,  is  favorable  to  the  formation  of  carbon 
monoxide,  only  traces  of  the  latter  are  formed.  Above  700°  the  proportion  of  car- 
bon monoxide  to  carbon  dioxide  increases  rapidly  until  995°  is  reached,  where  the 
former  gas  is  formed  exclusively.  An  increase  of  the  incandescent  bed  of  coal  does 
not  suffice  to  form  carbon  monoxide  if  the  minimum  of  temperature  (700°  C.)  be 
not  exceeded.  These  observations  explain  why  if  carbon  be  oxidized  at  a  lower 
temperature  than  700°,  it  burns  without  flame,  while  if  it  be  oxidized  at  a  higher 
temperature  the  combustion  is  accompanied  by  a  flame.  In  the  first  place  the  car- 
bon burns  directly  to  dioxide,  an  incombustible  gas,  and  in  the  latter  to  monoxide, 
which  at  a  higher  temperature  burns  with  a  further  part  of  oxygen  producing  the 
characteristic  blue  flame." 

Endothermic  Agents. — Endothermic  values  of  various  agents  apparently 
decrease  with  the  sensible  temperature.  In  the  case  of  steam  this  is  probably  caused 
by  the  lessened  amount  of  saturation,  or  entrained  water  contained  at  high  tem- 
peratures and  the  endothermic  extraction  of  heat  by  such  water,  due  to  the  latent 
heat  absorbed  in  transformation  of  water  vapor  into  steam. 

This  possibly  accounts  also  for  the  small  clinkering  sometimes  consequent 
from  systems  using  an  air  blast,  saturated  with  moisture,  or  "  low  pressure  "  (highly 
saturated)  steam.  Such  results  are  often  extremely  noticeable.  The  fuel  economy 
of  such  an  arrangement  is  doubtful;  this  additional  heat  abstraction  being  at  the 
expense  of  fuel;  but  undeniably  it  possesses  advantages  where  the  coal  used  contains 
a  high  percentage  of  fusible  ash. 

A  condition  analogous  to  the  above  just  stated  possibly  obtains  in  the  conten- 
tion of  certain  water-gas  engineers,  who  claim  that  the  use  of  superheated  steam 
(steam  containing  no  saturation  or  entrained  water),  subtends  intractable  clinkers 
and  excessive  clinkering  in  water-gas  generators.  It  is  also  a  fact  and  a  coincidence 
that  CC>2  loses  its  endothermic  value  directly  with  its  increase  in  temperature.  This 
being  due  of  course  to  its  lessened  density.  Many  lignites  and  some  coals  contain 
so  much  moisture  as  to  require  no  extraneous  endothermic  agent.  The  fact  would 
seem  to  have  some  bearing  on  the  above. 

In.  the  use  of  these  high  moisture  fuels  requiring  no  endothermic  agents,  it  is 
usually  best  to  carry  a  small  quantity  of  water  in  the  ash  pit,  which  performs  the 
dual  function  of  collecting  and  solidifying  the  finely  powdered  ash  when  falling,  and 


PRODUCER   OPERATION  13 

the  small  evaporation  of  which  tends  to  cool  the  grate  bars  on  up-draft  apparatus. 
It  must  be  remembered  that  the  moisture  in  this  fuel  is  in  the  form  of  water  or 
steam,  hence  in  the  latent  heat  of  combustion  there  is  a  larger  heat  absorption 
and  abstraction  from  the  fire  than  would  otherwise  be. 

Unless  there  is  an  unusually  large  percentage  of  fusible  ash  in  the  fuel  the  writer 
is  inclined  to  think  that  the  endothermic  agent  is  unnecessary  in  a  fuel  of  a  higher 
moisture  content  than  15%  or  certainly  18%.  This  would  show  a  content  of  less 
weight  of  water  per  pound  of  fuel  than  that  which  would  be  used  when  artificially 
supplied  to  the  producer  as  an  endothermic  agent  in  the  form  of  steam.  This,  how- 
ever, must  be  accounted  for  as  follows: 

First,  by  reason  of  the  latent  heat  of  absorption,  as  before  suggested,  and  also 
by  the  fact  that  this  moisture,  arising  in  the  form  of  aqueous  vapor  through  the 
fire  bed,  creates  a  high  degree  of  "  over- ventilation  "  with  a  consequently  reduced 
flame  temperature. 

This  result  is  dual,  preventing  as  it  does  a  flame  temperature  which  would  dis- 
sociate the  water  vapor  into  its  constituent  gases;  they  therefore  leave  the  producer 
in  the  form  of  aqueous  vapor,  hence  maintaining  it  at  a  very  low  fuel  bed  tempera- 
ture by  reason  of  its  high  specific  heat  and  the  ventilation  of  the  producer  as  a  whole 
by  the  large  masses  of  aqueous  vapor  leaving  with  its  gases,  and  the  high  specific 
heat  of  its  mixture. 

Although  the  theoretical  heat  required  to  raise  the  gases  to  their  sensible  tem- 
perature of  efficiency  is  17.2%,  Euchene  showed  in  the  particular  producer  in  which 
his  experiments  were  conducted  that  22.3%  of  the  initial  thermal  content  of  the 
coke  was  removed  by  the  sensible  heat  of  the  influent  gases.  This  difference  of  5.1%. 
may  be  accounted  for  by  the  high  sensible  heat  or  coefficient  of  heat  absorption 
of  the  aqueous  vapor,  hydrocarbon,  or  tarry  matter  mechanically  entrained  in  the 
gas,  robbing  the  producer  of  the  additional  heat  aforesaid. 

Assuming  22.3%  as  an  arbitrary  figure  for  effluent  temperature,  5.7%  the  loss 
of  radiation,  we  have  a  total  of  28%,  and  deducting  this  from  the  30.6%,  the  theoretical 
portion  of  the  heat  content  of  the  fuel  liberated  within  the  producer,  we  find  a  per- 
centage of  2.6%  or  residual  heat. 

As  a  matter  of  fact  this  residual  heat  is  much  higher  owing  to  a  certain  amount 
of  complete  combustion  occurring  within  the  producer  as  well  as  the  combustion 
of  hydrocarbons  of  the  high  heat  value,  but  even  under  ideal  conditions  and  with 
a  pure  fuel  carbon  this  discrepancy  would  be  found  which  it  is  necessary  to  absorb 
by  the  admission  of  some  endothermic  agent  such  as  steam  or  the  products  of  com- 
bustion. 

Test  Flame. — Within  certain  limits  the  operation  of  producers  may  be  observed 
with  a  fair  degree  of  accuracy  through  the  "  test  light,"  especially  if  one,  such  as 
is  shown  in  the  accompanying  illustration,  be  used.  In  this  light,  the  gas  is  supposed 
to  be  impinged  against  the  top  of  the  burner  arid  delivered  to  the  orifice  at  the  side 
at  about  atmospheric  pressure.  At  this  point,  if  it  burns  fully,  following  the  entire 
throat  or  orifice  with  a  complete  annular  flame,  the  quality  of  the  gas  may  be  said 
to  be  good  as  a  rule,  with  a  low  content  of  C02. 

If  its  emission  is  however  irregular,  burning  principally  in  the  top  of  the  orifice 
and  failing  to  follow  it  throughout  its  circumference,  it  is  usually  a  sign  of  high 


14 


GAS   PRODUCERS 


Water  //7/fc-/ 


Gas 


Pressure  Gtsa?* 


•^ 

—    -^ 

| 

<- 

1 
1 

tt 

b 

\  > 

1 
| 

J"  ul 

•--  —  • 

^> 
—  S 

i 

L 

--r1 

i 
i 

1 

i 

1 

1 

1 

1 

1 

L_J 

1 

! 

1 

i 

i 

L_ 

J 

carbonic  acid  and  low  heat 
value  in  the  gas,  when  the 
gas  may  be  said  to  be 
"lean." 

Theoretically,  of  course, 
the  color  of  a  flame  is  de- 
pendent upon  incompleted 
combustion  and  the  parti- 
cles of  combustible  matter 
heated  to  a  condition  of 
incandescence.  It  will  be 
found  that  various  fuels 
vary,  particularly  in  their 
color,  but  as  a  general  rule 
the  flame  of  the  "  test 
light  "  will  be  observed  to 
burn  from  blue  to  red,  with 
the  increasing  heat  of  the 
producer. 

Hydrogen,  carbonic 
acid,  alcohol,  etc.,  are  sup- 
posed to  burn  when  in  a 
state  of  purity,  with  a  per- 
fectly colorless  flame. 

Inasmuch  as  it  is  prac- 
tically impossible  to  burn 
all  of  the  combustible  or 
fuel  of  the  producer  to  CO, 
some  of  the  fuel  being  com- 
bined to  C02,  the  curve  B 
of  Chart  I  does  not  indicate 
the  real  temperature,  but 
by  reference  to  the  curve  C, 
this  temperature  may  be 
found  in  a  producer  where 
the  percentage  of  carbon 
burned  to  C02  is  plotted 
on  the  X  axis  and  the 
temperatures  upon  the  Y 
axis. 

This  percentage  would 
give  but  100%  CO  and  0% 
C02  at  the  Y  axis,  the  per- 
centage of  CO  decreasing 
and  that  of  C02  increasing 
as  the  abscissa  is  increased 


FIG.  3. — The  Tait  Test  Flame,  Burner,  etc. 


PRODUCER   OPERATION  15 

to  a  point  where  the  entire  amount  of  carbon  is  burned  to  100%  CO2  with  0%  of  CO. 
Hence,  for  any  analysis  of  flue  gas  produced,  the  actual  temperature  in  the  furnace 
may  be  determined,  by  reference  to  the  curve  C  aforesaid,  providing  of  course  that  no 
cooling  or  retarding  agent  has  been  employed  and  that  the  oxygen  of  combustion 
has  been  obtained  from  the  atmosphere  at  a  temperature  approximating  60°  F. 

Although,  under  average  conditions  of  operation,  the  test  light  may  be  used, 
manipulating  the  producer  as  aforesaid,  frequent  analyses  of  the  gas  should  be  taken, 
as  a  check  and  safeguard,  and  an  empyric  comparison  made  with  general  conditions 
of  operation,  the  aforesaid  light,  etc.,  to  form  basic  conditions  and  comparison. 

Where  the  producer  gas  shows  a  content  of  CO2  (this  representing  some  20% 
of  the  carbon  which  is  burned  to  C02)  the  temperature  is  indicated  by  the  curve  C, 
which  is  approximately  2400°  F. 

Above  this  point,  in  most  instances,  a  clinker  mass  of  incombustible  vitrified 
scoria  is  formed.  For  each  fuel  there  is  a  critical  temperature  approximately  in 
this  neighborhood,  and,  as  already  stated,  to  prevent  this  a  somewhat  lower  heat 
must  be  maintained.  This  is  difficult,  inasmuch  as  the  heat  above  outlined  given 
off  in  combustion  of  C  to  CO,  considerably  exceeds  both  the  radiation  of  a  well- 
built  furnace  and  the  sensible  heat  wThich  may  be  carried  off  by  the  outgoing  gas, 
at  the  specific  heat  which  it  maintains  at  that  degree  of  temperature. 

Steam  Cooling. — It  will  be  manifest  therefore  that  either  a  portion  of  steam 
or  a  part  of  the  products  of  combustion  must  be  used  to  temper  this  fire. 

Butterfield  says  (page  86):  "All  undecomposed  steam  passing  through  a 
retort-heating  system  (producer,  furnace,  etc.)  robs  that  system  of  heat,  and  thereby 
makes  the  prevailing  temperatures  lower  than  they  would  be  in  the  absence  of  unde- 
composed steam.  The  temperature  at  which  the  spent  gases  escape  into  the  chimney 
is  a  measure  of  the  net  loss  to  the  system  as  a  whole,  but,  if  the  spent  gases  traverse 
regenerative  passages  before  escaping  to  the  chamber,  the  loss  of  heat  to  the  pro- 
ducer per  se  (if  recuperation  is  not  applied  to  the  primary  as  well  as  to  the  secondary 
air  supply)  may  be  greater  than  the  net  loss  to  the  system.  Hence,  the  passage 
of  steam,  in  excess  of  that  wrhich  the  fuel  can  decompose  through  the  system,  usually 
should  be  felt  far  more  seriously  in  the  producer  than  elsewhere  in  the  system.  The 
escape  of  undecomposed  steam  from  the  producer  implies  that  heat  has  been 
abstracted  by  this  steam  from  the  bed  of  fuel,  the  temperature  of  which  is  thereby 
lowered,  but  the  lowering  of  the  temperature  of  the  bed  of  fuel  renders  it  less  com- 
petent to  decompose  steam  and  form  carbonic  oxide  rather  than  carbonic  acid. 

'  The  undecomposed  steam  injures  the  working  of  the  producer  indirectly  as 
well  as  directly.  Every  endeavor  should  therefore  be  made  to  avoid  more  steam 
traversing  the  bed  of  fuel  than  it  can  decompose,  unless  it  can  be  shown  that  some 
very  great  collateral  advantage  accrues  from  the  excessive  steam.  Now,  the  only 
advantages  which  can  be  reasonably  claimed  for  a  large  inflow  of  steam  to  the  ordi- 
nary producer,  are  cooling  of  the  fire  bars  and  avoidance  of  hard  clinker.  The 
practical  question,  therefore,  is  whether  these  advantages  cannot  be  secured  to  an 
adequate  extent  without  the  steam  supply  exceeding  that  which  the  bed  of  fuel  is 
competent  to  decompose.  Actually,  it  would  appear  that  this  question  has  not 
been  satisfactorily  investigated,  but  it  may  be  assumed  that  the  answer  would  be 
different  for  different  types  of  producers  and  different  description  of  coke,  much 


16 


GAS   PRODUCERS 


depending  on  the  area  of  the  grate  relatively  to  the  air  and  steam  supply  and  on 
the  temperature  at  which  the  ash  of  the  coke  fluxes.  Nevertheless,  there  is  no  doubt 
that  it  is  very  rarely  that  steam  in  excess  of  the  quantity  which  will  be  decomposed, 
is  required  to  keep  the  fire  bars  adequately  and  avoid  clinker  being  formed  to  an 
obstructive  extent." 

As  is  stated  above  by  Butterworth,  the  producer  is  "  robbed  "  of  its  excess 
heat  accumulated  in  the  combustion  of  C  to  CO  by  the  dissociation  of  the  steam 
applied  and  (in  practice)  the  thermal  capacity  of  escaping  aqueous  vapor.  In  the 
processes  covered  by  the  Tait-Ellis,  Elclred,  and  Doherty  patents,  this  heat  is 

absorbed  in  the  endothermic  reaction  of  C02  to  CO, 
the  intention  being  to  create  through  this  reaction  a 
potential  out  of  a  neutral  gas. 

Otherwise,  as  before  described,  the  fuel  bed  will 
get  hotter  and  hotter,  causing  the  ash  to  fuse  to  clinker 
and  give  trouble  in  cleaning  out.  Steam  serves  to  keep 
the  producer  in  good  working  condition,  but  in  addition 
some  of  the  steam  is  decomposed,  so  that  the  resulting 
gas  will  contain  some  carbonic  acid  and  carbonic  oxide, 
oxygen  and  some  hydrogen  derived  from  the  steam. 

Ingalls  (page  283)  states:  "  The  use  of  steam  in  the 
producer  presents  the  further  advantage  that,  in  cooling 
the  zone  of  combustion,  the  trouble  from  clinkering  of 
the  ash  is  reduced.  In  many  cases  this  is  a  highly 
important  consideration.  The  effect  of  blowing  a  pro- 
ducer with  a  very  large  volume  of  steam  is  shown  by 
the  results  of  the  Mond  producer.  The  gas  from  that 
is  developed  at  a  very  low  temperature  and  is  conse- 
quently high  in  carbon  dioxide,  but  because  of  its  high 
tenor  in  hydrogen  it  possesses  a  great  calorific  power." 
In  view  of  the  theoretical  and  practical  consid- 
erations substantiated  by  the  authorities  referred  to, 
there  can  be  no  question  as  to  the  impracticability  of 
operating  a  producer  furnace  without  the  use  of  some  cooling  agent;  that  is,  the  tem- 
perature must  be  reduced  and  maintained  at  a  point  that  will  restrain  the  rapid 
formation  of  clinkers.  There  is  always  an  unavoidable  loss  of  heat  when  steam  is 
used  as  a  cooling  agent.  This  loss  may  be  much  reduced  by  means  of  a  proper 
system  of  recuperation,  but  as  the  recuperation  can  never  reach  an  efficiency  of  100% 
the  loss  can  never  be  reduced  to  zero. 

By  reference  to  Sheet  No.  2,  curve  E  represents  the  unavoidable  loss  in  B.T.IL 
due  to  the  passing  of  one  pound  of  steam  through  the  producer  and  furnace  where  the 
efficiency  of  recuperation  is  65%,  which  is  a  recuperation  of  extremely  high  efficiency 
and  seldom  reached  in  practice,  and  contemplates  the  reduction  of  the  products  of  com- 
bustion from  a  temperature  of  2300°  F.  to  800°  F.;  but  even  this  degree  of  recupera- 
tion results  in  a  loss  of  223  B.T.U.'s  for  every  pound  of  steam  so  passed  through 
the  system.  Curve  F  is  similar  to  curve  E,  but  shows  the  loss  due  to  each  pound 
of  steam  passing  through  the  system  with  a  recuperation  of  46%  efficiency,  which 


FIG.  4.— Tait  Producer  Gas  Test 
(Section  of  Burner  on  Fig.  3). 


PRODUCER   OPERATION 


17 


closely  approximates  the  usual  practice  (see  test  of  Calkins),  and  contemplates  a 
reduction  of  temperature  of  the  waste  gases  or  products  of  combustion  from  2300°  F. 
to  1200°  F.  In  this  case  the  unavoidable  loss  due  to  the  use  of  each  pound  of  steam 
passing  through  the  system  is  592  B.T.U.'s.  Curve  G  represents  the  loss  with  zero, 
or  no  recuperation,  and  amounts  to  1645  B.T.U.'s  per  pound  of  steam  used. 

EFFECT  OF  STEAM  ON  QUALITY  AND  QUANTITY  OF  GAS 


Constituents  of  Gas. 

Air  Gas  by  3. 

Mixed  Gas  by  3  and  5. 

Mixed  Gas  by  3  and  6. 

Vol- 
umes. 

Cubic 
Feet. 

Per  Cent 
by  Vol. 

Vol- 
umes. 

Cubic 
Feet. 

PerCent 
by  Vol. 

Vol- 
umes. 

Cubic 
Feet. 

Per  Cent 
by  Vol. 

CO  from  air  

2.0 

715.6 

34.7 

2.0 
1.0 
1.0 

715.6 
357.8 
357.8 

25.7 
12.9 
12.9 

2.00 

1.96 
.98 
3.77 

715.6 

701.2 
350.6 
1348.8 

23.0 

22.5 
11.2 
43.3 

CO  from  steam  .  .       .    . 

H  from  steam         .    . 

CO2  from  steam 

N  from  air           

3.77 

1348.8 

65.3 

3.77 

1348.8 

48.5 

Volume  of  gas  produced  . 

5.77 

2064.4 

100.0 

77.6 

2780.0 

100.0 

8.70 

3116.2 

100.0 

Volume  of  gas  per  Ib.  C 
Combustible  in  gas  . 

86  cubic  feet 
34.7% 

119  B.T.U. 

None  used 
7  1.2  cubic  feet 

77.2  cubic  feet 
51-5% 

176.9  B.T.U. 

.  5  pound 
47  .  5  cubic  feet 

87.2 
45.5% 

156.8  B.T.U. 

.98  pound 

47.8 

Calorific  power  per  cubic 
foot.                

Steam   decomposed   per 
Ib   of  C 

Air  required  per  Ib.  of  C  . 

QUALITY  OF  GAS  WITH  VARYING  STEAM 


Gases  by  Volume. 

Excess  of  Steam. 

Moderate. 

Great. 

Maximum. 

CO,. 

5.30% 

8.90% 

15.00% 

CO  

23.50 

16.40 

11.50 

CH4 

3.30 

2.55 

1.90 

H  .    . 

13.14 

18.60 

24.60 

Heat  value  per  cubic  foot  . 
Temperature  

151  B.T.U. 
1472°  F. 

135  B.T.U. 
1292°  F. 

129  B.T.U. 
932°  F. 

For  good,  average  working  in  an  ordinary  producer  6%  of  the  weight  of  the 
blast  may  be  steam,  or  by  volume  about  10%  steam  and  90%  air.  This  is  equiv- 
alent to  one-fifth  of  the  C  being  burnt  by  steam  and  four-fifths  by  air.  About  25% 
more  steam  sometimes  may  be  used,  and  the  steam  may  be  figured  as  one-third 
to  two-fifths  of  the  coal  gasified,  or  approximately  a  boiler  H.P.  per  ton  for  24 
hours. 

Curve  "  H  "  shows  the  total  cooling  effect,  or  heat  absorbed  by  introducing 
one  pound  of  steam  at  212°  F.  to  the  fuel  bed,  wherein  certain  percentages  of  the 
pound  of  steam  are  decomposed,  and  the  remaining  part  passes  through  the  fuel  bed 


18 


GAS    PRODUCERS 


not  decomposed,  but  merely  as  superheated  steam.  It  will  be  seen  that  commencing 
with  330  B.T.U.  absorption,  lepresenting  no  decomposition,  the  heat  absorbed  is  merely 
that  required  to  raise  the  steam  from  212°  to  1500°  F.,  which  represents  the  absorp- 
tion of  330  B.T.U.'s.  As  the  abscissa  is  increased,  representing  an  increased  percentage 
of  decomposition,  the  heat-absorbing  effect  increases  until  the  100%  line  is  reached, 
where  the  entire  amount  of  heat  absorbed  by  the  decomposition  of  one  pound  of 
steam,  amounts  to  6060  B.T.U.'s. 

It  is  now  possible  to  determine  the  amount  of  steam  that  will  be  required  per 
pound  of  combustible  consumed,  in  order  to  maintain  the  temperature  of  the  fuel 


_£« 


tnt*o 


>* 


S      C 


'X 
•a/Jet* 


5HEET 


FIG.  5. — Relation  of  Combustion  to  Temperature. 

in  the  producer  at  a  predetermined  point,  provided  we  know  the  approximate  pro- 
portions of  each  pound  of  steam  introduced  to  the  fuel  bed  that  will  be  dissociated, 
which  fact  may  be  approximated  by  analyzing  the  gas  issuing  from  the  producer. 
As,  for  example,  suppose  it  is  desired  to  maintain  the  temperature  of  the  fuel  bed 
at  approximately  1500°  F.  in  view  of  the  fact  that  one-fourth  or  25%  of  the  carbon 
consumed  is  burned  to  carbon  dioxide  (CO2).  By  reference  to  curve  C,  we  find  that 
the  natural  temperature  of  the  furnace,  if  no  cooling  medium  be  employed,  would 
be  approximately  2440°  F.;  therefore  for  each  pound  of  combustible  consumed 
to  reduce  the  temperature,  there  would  have  to  be  the  difference  in  the  number  of 
B.T.U.'s  in  6.79  Ibs.  of  gas  at  2440°  F.  and  the  same  weight  of  gas  at  1500°  F.  =3572 


PRODUCER   OPERATION 


19 


B.T.U.  (For  the  specific  heat  of  the  furnace  gases  at  this  temperature  see  Curves, 
Sheet  No.  5.)  Therefore,  there  must  be  absorbed  something  in  excess  of  3572  B.T.U.'s; 
that  is,  for  each  pound  of  carbon  burned  in  the  producer  there  must  be  passed 
through  the  bed  of  fuel  enough  steam  so  that  by  its  latent  heat  and  heat  required 
to  cause  dissociation  of  the  steam,  there  will  be  absorbed  3572  B.T.U.'s. 


X 

r 

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vX>  f 

a.te<6 

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5Y 

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11 

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NL. 

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FIG.  6. — Effect  of  Steam  on  Lowering  Heat  of  Fuel  Bed. 


By  reference  to  Curve  //,  Sheet  No.  2,  may  be  determined  the  cooling  effect 
produced  (or  heat  absorbed),  by  the  chemical  dissociation  of  steam.  It  is  a  demon- 
strable fact  that  of  all  the  steam  introduced  to  a  bed  of  incandescent  fuel  only  a 
fractional  part  is  dissociated. 

Butterfield  says  (page  86) :  "It  would  therefore  seem  that  Euchene's  researches 
support  the  assumption,  which  theoretical  considerations  warrant,  that  when  the 
water  evaporated  from  the  ash  pan  in  a  given  time  exceeds  in  quantity  that  which 


20 


GAS   PRODUCERS 


the  bed  of  fuel  in  the  producer  is  capable  of  decomposing,  the  undecomposed  steam 
abstracts  heat  from  the  fuel,  while  the  decomposed  steam  yields  practically  no 
carbon  oxide,  but  only  hydrogen  and  carbonic  acid." 

Assuming  that  70%  of  the  steam  is  decomposed  under  these  conditions,  each 
pound  of  steam  introduced  to  the  furnace  will  absorb  4350  B.T.U.'s;  therefore,  for 


-ee* 


-«* 


-»* 


/P%    2)0% 
&1 


3}Q%    4)0%    5|fX     fi|0»    fy%sy%,    9\>%    Jtyo% 

viAstiMk. 


l/fei{nef 


is  o.3. 


Tbani  of 


FIG.  7. — Influence  of  Quantity  of  Steam  on  Heat  Absorbed. 

3572 
each  pound  of  combustible   consumed,  there  would  be  required  j^-..=0.82   Ib.    of 


steam  introduced  to  the  bed  of  fuel,  or  the  ratio  of  steam  required  to  that  of  com- 
bustible used  would  be  82%.  By  referring  to  Curves  /,  J,  and  K,  Sheet  No.  3, 
which  curves  represent  various  degrees  of  recuperation,  will  be  shown  the  amount 
of  heat  (in  B.T.U.'s  per  pound  of  combustible  used)  that  is  absolutely  and  unavoid- 
ably lost,  due  to  the  use  of  steam  as  a  means  of  cooling  the  fire.  Considering  the 


PRODUCER    OPERATION 


21 


problem  in  hand,  and  with  a  recuperation  of  65%  efficiency  there  is  lost  per  pound 
of  fuel  consumed  270  B.T.U.'s.;  with  47%  recuperation  580  B.T.U.'s,  and  with  zero 
recuperation  about  1600  B.T.U.'s.  Thus  it  may  be  seen  that  for  every  pound  of 
steam  introduced  to  the  bed  of  fuel  there  is  always  an  unavoidable  loss  of  heat,  and 
the  efficiency  of  steam  as  a  cooling  agent  must  always  remain  below  100%. 


FIG.  8. — Influence  of  CO2  on  Temperature. 

In  addition  to  this  loss  of  heat,  there  is  always  the  direct  loss  required  to  raise 
water  from  a  temperature  of  say  60°  F.  to  steam  at  212°  F.,  amounting  to  1118 
B.T.U.'s.  This  heat  must  be  supplied  from  some  source  at  the  expense  of  the  com- 
bustion of  fuel. 

Reduction  of  C02  to  CO. — Kent  says  (page  456) :  "  By  the  decomposition  of 
a  chemical  compound  as  much  heat  is  absorbed,  or  rendered  latent,  as  was  evolved 
when  the  compound  was  formed.  If  1  Ib.  of  carbon  is  burned  to  CO2,  generating 
14,544  B.T.U.,  and  the  CO2  thus  formed  is  immediately  reduced  to  CO  in  the 


22 


GAS   PRODUCERS 


presence  of  glowing  carbon,  by  the  reaction  C02+C  =  2CO,  the  result  is  the  same 
as  if  the  2  Ibs.  C  had  been  burned  directly  to  2CO,  generating  2x4451=8902  heat 
units;  consequently  14,544-8902  =  5642  heat  units  have  disappeared  or  become 
latent,  and  the  "  unburning  "  of  CO2  to  CO  is  thus  a  cooling  operation." 

By  burning  1  Ib.  of  carbon    in    oxygen    to  CO2,  there    are    produced  3§  Ibs.  of 
CO2  gas,  and  there  are  liberated  about  14,544  B.T.U.;   by  the  reduction  or  "  unburn- 


0. 1         0.3L         0.3 

FIG.  9. — Influence  of  Temperature  on  Specific  Heat. 

ing  "  of  3§  Ibs.  of  C02  to  CO  there  are  absorbed  5642  B.T.U.,  therefore  by  the  reduc- 
tion of  1  Ib.  of  C02  to  CO,  there  are  absorbed  5642  B.T.U. +  3§  Ibs.,  which  equals 
1540  B.T.U.  of  heat. 

Consequently  by  the  decomposition  of  one  one-hundredth  of  a  pound  there  are 
absorbed  1540^-100  =  15.4  B.T.U. 

As  the   average   specific   heat   of  any   gaseous   mixture    (consisting  of  products 


PRODUCER   OPERATION 


23 


of  combustion,  steam  and  air),  can  be  closely  approximated  (by  reference  to  the 
curves  on  Sheet  No.  5)  the  cooling  effect  on  a  fuel  bed  of  such  a  mixture  contain- 
ing varying  percentages  of  C02,  by  weight  or  volume,  may  be  determined. 

By  referring  to  Sheet  No.  4  can  be  seen  curves  which  indicate  the  temperatures 
at  which  various  mixtures  of  products  of  combustion  (varying  in  their  percentage 
of  C02)  must  be  introduced  to  a  bed  of  incandescent  carbon  in  order  to  cause  any 


ifoo 


3250 


4USO 
4000 

use 

/500 


7S, 


Centiyrf.de- 


5HEET 


No.C 


-f^rf  7alrexlfH-  = 


TiJe,   WtttyJ'-&) 


Sco      4cc      fee       Sec     //JV     utt     /fee     /ffffc     t9&     &co     tice      t4oo    -?-Svc 

FIG.  10. — Conversion  of  Centigrade  and  Fahrenheit  Degrees. 

change  of  temperature  of  the  fuel  bed,   with  the  understanding  that  all  the  C02 
present   is   reduced  to  CO. 

To  represent  these  temperatures  different  curves  are  required  for  different 
temperatures  of  fuel  beds,  as  the  average  specific  heat  of  the  gaseous  mixture  varies 
with  its  change  of  temperature.  By  the  use  of  Curves  Nos.  1,  2,  3,  4,  5  and  6,  on 
Sheet  No.  4,  if  the  temperature  of  the  fuel  bed  and  the  percentage  of  CO2  present 
in  the  gaseous  mixture  introduced  thereto  be  known,  the  fact  can  be  determined 


24  GAS   PRODUCERS 

as  to  whether  the  net  result  is  a  heating  or  cooling  of  the  fuel  bed;  also  the  tem- 
perature of  the  gaseous  mixture  can  be  determined  at  which  there  will  be  neither 
a  cooling  or  heating  of  the  fuel  bed;  that  is,  where  there  will  be  no  exchange  of 
heat  between  the  fuel  bed  and  the  gaseous  mixture.  For  example,  if  there  is  8% 
CC>2  in  the  gaseous  mixture  introduced  to  the  fuel  bed  which  has  an  average  tem- 
perature of  1500°,  the  gaseous  mixture  must  have  a  temperature  of  378°  F.  higher 
than  the  fuel  bed  in  order  to  produce  neither  a  heating  or  cooling  effect  (see  Curve 
No.  2),  or  a  total  temperature  of  (1500° +  378°)  1878°  F.  If  the  temperature  of 
the  gaseous  mixture  is  below  1878°  F.  the  gases  will  cool  the  fuel  bed;  if  above 
1878°  F.  they  will  heat  the  fuel  bed. 

On  Sheet  No.  5  are  curves  representing  the  specific  heats  at  varying  tempera- 
tures under  constant  pressure  (14.7  pounds  absolute)  of  the  gases,  carbon  dioxide, 
oxygen,  nitrogen,  carbon  monoxide,  and  superheated  steam. 

On  Sheet  No.  6  is  a  curve  to  assist  in  transferring  temperature  readings  from 
Fahrenheit  scale  to  centigrade  scale  and  vice  versa. 

In  using  suction  producers  of  the  ordinary  up-draft  type  with  the  exhaust  gas, 
or  connection  (C02  as  an  endothermic)  during  cleaning  periods,  it  is  possible  by 
opening  wide  the  exhaust  within  the  producer  to  create  an  equilibration  of  pres- 
sure in  such  a  manner  that  any,  or  all,  doors  may  be  temporarily  opened. 

This  can,  of  course,  only  be  maintained  for  a  few  moments  by  reason  of  the 
strong  heat-absorbing  nature  of  the  exhaust  gas  and  the  tendency  to  kill  the  fire. 

Connections. — The  standard  practice  generally  dictated  is  that  producer  out- 
let connections  should  be  about  one-eighth  the  diameter  of  the  producer,  internal 
diameters  being  taken  or  measurements  in  the  clear  of  both  producers  and  connec- 
tions. However,  it  is  customary  among  most  manufacturers  to  make  the  inlet  to 
the  suction  producer  about  one-sixth,  and  the  outlet  about  one-fifth;  the  outlet 
in  most  suction-producer  practice  being  about  10%  greater  than  the  inlet  in  the  clear. 

It  would  seem  that  with  suction  producers  the  connection  between  the  pro- 
ducer and  scrubber  should  be  as  large  as  possible,  and  should  be  limited  only  by 
cost  of  construction,  for  two  reasons.  First,  there  is  greater  freedom  from  friction, 
and  second,  and  more  important,  there  is  less  wire  drawing  and  consequent  channel- 
ing of  the  gases  through  the  fuel  bed. 

According  to  one  manufacturer,  the  flue  areas  of  a  producer  should  be  as 
follows:  Ample  area  of  flue  is  important,  and  the  more  so  in  bituminous  practice. 
In  general,  the  diameter  of  the  producer  connection  should  be  about  one-quarter 
the  diameter  of  the  producer,  and  in  a  collecting  flue  from  several  producers  its 
area  in  like  proportion  should  not  be  less  than  one-sixteenth  of  the  gas-making 
area  of  the  attached  producers.  Thus  a  producer  8  feet  inside  diameter  of  lining 
should  have  a  connection  at  least  24  inches  internal  diameter.  As  such  a  producer 
may  readily  gasify  600  pounds  of  coal  hourly,  the  flue  area  is  about  equal  to  one 
square  foot  per  200  pounds  of  coal  gasified  hourly. 

Sizes. — Shaft  producers  should  not  be  made  smaller  than  an  internal  diameter 
of  3  ft.  6  in.  unless  intended  to  operate  with  charcoal,  and  should  not  exceed  in  out- 
side diameter  12  ft. 

The  former  limit  is  regulated  by  a  certain  structural  difficulty  in  the  way  of 
linings  and  mechanical  difficulties  in  the  removing  of  ash  and  clinker,  but  more 


PRODUCER   OPERATION 


25 


particularly,  by  the  loss  which  is  also  applicable  to  gas  engines  and  all  furnaces; 
namely  that  whereas  the  volume  or  content  of  a  furnace  increases  as  the  cube  of 
the  linear  dimensions,  the  surface  merely  increases  as  the  square. 

That  is  to  say,  where  a  small  producer  may  have  a  certain  ratio  of  radiating 
surface  to  fuel  bed,  this  ratio  is  materially  lessened  in  the  large  sizes,  with  a  corre- 
sponding increase  of  efficiency  or  decrease  in  the  per  cent  of  "  jacket  loss."  The 
radiation  increasing  as  the  square,  and  the  capacity  as  the  cube  of  the  lineal 
dimensions. 

The  latter  limit  is  regulated  by  structural  difficulties  in  the  maintaining  of 
rectitude  in  the  linings  and  more  especially  by  mechanical  difficulties,  the  stoking 
of  the  producer,  the  packing  of  the  fuel  bed,  and  the  control  of  the  angle  of  repose 
of  fuel.  Also  there  is  much  greater  difficulty  and  loss  of  fuel  with  the  removal  of 
clinker  and  ash  which  may  become  imbedded  within  the  heart  of  the  fire. 

Weights. — The  approximate  weight  of  suction  gas  producer  sets,  including  all 
apparatus  and  fire  brick,  based  upon  the  Muenzel  Suction  Producer  are  as  follows: 


H.P. 

Weight. 

H.P. 

Weight. 

20 

9,000 

110 

19,800 

25 

9,460 

120 

20,100 

30 

9,680 

130 

21,500 

35 

10,120 

140 

23,000 

40 

10,560 

150 

24,300 

50 

11,000 

160 

25,100 

60 

12,760 

170 

26,000 

70 

14,080 

180 

27,500 

80 

16,900 

190 

28,700 

90 

17,160 

200 

29,200 

100 

18,000 

250 

36,500 

A  250  h.p.  pressure  producer  complete,  with  holder,  without  fire-brick,  but 
with  connection,  weighs  48,000  Ibs. 

The  above  does  not  include  piping  and  auxiliaries,  which  usually  equal  10% 
in  addition  to  the  sets  above  specified. 

APPROXIMATE  SPACE  REQUIRED  FOR  SINGLE  UNIT  GAS  POWER  PLANTS 


H.  P. 

Suction. 

Pressure.* 

Gas  Holders. 

Length, 
Feet. 

Width, 
Feet. 

Head 
Room, 
Feet. 

Length, 
Feet. 

Width, 
Feet. 

Head 
Room, 
Feet. 

Cubic 
Feet. 

Tank  Diameter. 

25-50 
50-75 
75-100 
150 
200 
300 
400 
500 
1000 

13-14 
14-15 
15-19 
20-21 
22-23 
25-26 

9-11 
10-12 
11-14 
13-15 
15-16 
16-17 

13-15 
14-17 
15-20 
19-20 
22-23 
23-25 

32 
34 
36 
2  units  39 
3  units  39 

16 
18 
20 
22 
47 

1000 
2000 
2500 
3000 
4000 
5000 
6000 
10000 
15000 

15  feet 
17  feet 
19  feet  6  inches 
21  feet  6  inches 
21  feet  6  inches 
24  feet 
30  feet  6  inches 
35  feet 
43  feet 

22-25 
23-25 
23-26 
23-26 
23-26 

*  Pressure   plants  exclusive   of  holder.     Area   depends  of  course   on   number  and  size  of  units 
for  the  total  power  given. 


26  GAS   PRODUCERS 

Producer  Shell. — The  writer  recommends  a  shell  of  ^-in.  steel  boiler  plate  for 
both  producer  and  scrubber.  This  should  be  thoroughly  riveted  with  the  best 
grade  of  i-in.  wrought-iron  rivets,  the  rivets  being  preferably  pneumatically  riveted 
and  all  joints  having  calking  edges,  contact  being  metal  to  metal  without  packing. 
To  test  the  tightness  of  the  producer  shell,  a  fuel  bed  of  three  feet  in  depth  is  charged 
in  the  producer,  and  the  entire  bed  brought  to  a  red  heat  of  combustion.  At  this 
point  18  inches  of  green  coal  is  added  to  the  top  of  the  fire,  and  gas  immediately 
drawn  from  the  producer.  This  gas  is  not  to  show  a  content  of  more  than  one  per 
cent  of  free  oxygen,  a  larger  amount  indicating  leakage  of  the  lining  or  connection 
of  the  producer. 

It  will  be  manifest  that  the  three  feet  of  solid  fire  bed  at  a  red  heat  is  for  the 
purpose  of  dissociating  all  air  passing  through  the  producer,  and  the  surface  of  green 
coal  is  to  act  as  a  condenser  to  lower  the  resultant  gas  to  a  temperature  below 
the  ignition  point  for  combination  with  free  oxygen,  and  thereby  prevent  secondary 
combustion  in  the  top  of  the  producer,  which  would  prevent  its  appearance  in  the 
necessary  analysis. 

Continuity. — Continuity  of  producer  operation,  of  course,  depends  upon  the 
nature  of  the  fuel  used,  and  the  proportion  of  load  or  demand  maintained  to  the 
capacity  of  the  apparatus. 

Generally  speaking,  on  lignite  or  bituminous  producers,  the  standby  period  of 
six  to  ten  hours  should  be  assumed  per  week,  where  the  service  is  continuous,  or 
twenty-four  hours  per  day. 

Several  Muenzel  producers  running  upon  anthracite  have  made  ninety  days 
continuous  run,  without  even,  a  momentary  intermission. 

The  durability  or  life  of  the  lining  of  the  producer  depends  much  upon  the  con- 
ditions of  operation  and  fuel  aforementioned. 

Under  proper  load,  and  with  careful  operation,  with  particular  reference  to 
preventing  secondary  combustions  occurring  in  the  producer  through  an  admission 
of  drafts,  holes  in  the  fire,  etc.,  the  durability  or  life  should  be  from  three  and  one- 
half  to  four  years. 

Fire-brick  Linings.— Gas  producers  in  furnaces  should  be  lined  with  fire-brick 
and  grouted,  between  the  lining  and  shells  or  outer  walls,  with  fire-clay,  pulverized 
brick-dust,  or  asbestos,  the  latter  being  preferable  by  reason  of  its  elasticity  and 
maintenance  of  position  after  temporary  strains.  It  is  also  less  inclined  to  cleavage, 
fissures,  cracks  or  chimneys.  The  brick  should  be  wet  before  setting,  the  mortar 
being  extremely  thin,  hardly  thicker  in  fact  in  consistency  than  whitewash,  and 
the  bricks  carefully  faced.  The  use  of  a  thick  or  putty-like  mortar  frequently  accounts 
for  buckling  or  skewbacks,  by  reason  of  having  a  coefficient  of  expansion  differing 
from  that  of  the  brick.  Leaks  in  producers  are  a  source  of  very  considerable  loss 
through  admitting  of  secondary  air,  and  should  be  most  carefully  avoided. 

As  a  wash  for  fire-brick  in  furnaces,  to  give  the  bricks  a  glaze  and  keep  carbon 
from  collecting  on  the  walls,  a  correspondent  of  Poiver  suggests  one  pound  of  salt 
to  a  pint  of  water,  mixed  with  fire-clay  and  applied  as  a  whitewash. 

One  ton  of  fire-clay  should  be  sufficient  to  lay  3000  ordinary  bricks.  To  secure 
the  best  results,  fire-bricks  should  be  laid  in  the  same  clay  from  which  they  are  manu- 
factured. It  should  be  used  as  a  thin  paste,  and  not  as  mortar.  The  thinner  the 


PRODUCER    OPERATION 


27 


joint  the  better  the  furnace  wall.     In  ordering  bricks  the  service  for  which  they  are 
required  should  be  stated. 

NUMBER  OF  FIRE-BRICK  REQUIRED  FOR  VARIOUS  CIRCLES  (KENT) 


Diam. 
of 
Circles 
Ft. 

KEY  BRICKS. 

ARCH  BRICKS. 

WEDGE  BRICKS. 

No.  4 

No.  3 

No.  2 

No.  1 

Total 

No.  2  No.  1 

9  in. 

Total. 

No.  2 

No.  1 

9  in.  Total 

1.5 

25 

25 

2.0 

17 

13 

30 

40 

42 

2.5 

9 

25 

34 

31 

18 

49 

60 

60 

3.0 

38 

38 

21    36 

57 

48 

20 

68 

3.5 

32 

10 

42 

10    54 

64 

36 

40 

76 

4.0 

25 

21 

46 

72 

72 

24 

59 

83 

4.5 

19 

32 

51 

72 

8 

80 

12 

79 

91 

5.0 

13 

42 

55 

72 

15 

87 

98 

98 

5.5 

6 

53 

59 

72 

23 

95 

98 

8 

106 

6.0 

63 

63 

72 

30 

102 

98 

15 

113 

6.5 

58 

9 

67 

72 

38 

110 

98 

23 

121 

7.0 

52 

19 

71 

72 

45 

117 

98 

30 

128 

7.5 

47 

29 

76 

72 

53 

125 

98 

38 

136 

8.0 

42 

38 

80 

72 

60 

132 

98 

46 

144 

8.5 

37 

47 

84 

72 

68 

140 

98 

53 

151 

9.0 

31 

57 

88 

72 

72 

147 

98 

61 

159 

9.5 

26 

66 

92 

72 

83 

155 

98 

68 

166 

10.0 

21 

76 

97 

72 

90 

162 

98 

76 

174 

10.5 

16 

85 

101 

72 

98   170 

98 

83 

181 

11.0 

11 

94 

105 

72 

105 

177 

98 

91 

189 

11.5 

5 

104 

109 

72 

113 

185 

98 

98 

196 

12.0 

113 

113 

72 

121 

193 

98 

106 

204 

12.5 

113 

117 

For  larger  circles  than  12  feet  diameter  use  113  No.  1  Key,  and  as  many  9-inch  brick  as  may  be 
needed  in  addition. 

For  further  information  upon  fire-clay  and  brick,  see  Chapter  XXI. 

Repairs  and  Maintenance  of  Producers  are  less  than  that  of  a  steam  plant  of 
the  same  power.  After  eighteen  months'  service  of  a  certain  plant  (about  400  H.P.) 
the  repairs  were  merely  nominal.  Producer  linings  are  known  to  have  stood  as 
long  as  ten  years,  and  in  any  case  should  stand  several  years.  From  15  to  25  cents 
per  horsepower  per  year  may  be  taken  as  an  approximate  estimate  for  repairs  of 
plants  up  to  500  H.P.,  so  that  the  usual  allowance  of  2  to  3%  of  its  cost  is  reason- 
ably close. 

Suction  linings  usually  require  repairs  sooner  than  pressure  producers,  but  of 
course  depends  on  the  grade  of  coal  used,  the  quality  of  the  brick,  the  workman- 
ship in  their  setting,  and  the  care  given  the  producer  in  operation. 

Shell  Insulation. — Conditions  effecting  loss  of  heat  by  radiation,  its  calculation 
and  measurement,  are  discussed  in  the  chapter  on  Furnaces. 

Under  ordinary  conditions  of  producer  construction  it  is  customary  to  have 
an  insulation  or  "  dead  "  space  between  the  fire-brick  lining  and  the  shell  varying 
from  one  to  two  inches  in  diameter.  However,  the  former  measurement  is  con- 
sidered sufficient  in  general  practice. 


28  GAS    PRODUCERS 

This  space  is  filled  with  some  non-conducting  matter  which  serves  the  dual 
purpose  of  insulating  the  fire  bed  and  reducing  the  loss  by  conduction  and  radiation 
to  the  atmosphere;  and  also  to  prevent  the  leakage  of  air  and  its  seepage  into  the 
fire,  between  the  brick;  and  the  channeling  of  air  between  the  lining  and  the  shell. 

In  circular  producers  this  insulation  or  dead  space  usually  consists  of  finely 
powdered  cinders,  sand,  or  fire-clay,  sand  and  asbestos,  and  even  in  some  instances 
several  thicknesses  of  asbestos  board  or  wool.  The  highest  efficiency  however  is 
obtained  by  a  filling  which  remains  more  or  less  plastic  and  elastic;  inasmuch  as  the 
taking  of  a  "  permanent  set  "  subtends  cracks  and  separation  from  the  lining  and 
shell  due  to  expansion  and  contraction,  and  the  jarring  of  the  lining  in  clinkering. 

While  sand  or  powdered  cinders  form  a  fair  material  for  circular  producers, 
some  form  of  grouting,  as  herein  described,  is  necessary  with  rectangular  producers, 
and  may  be  advantageously  used  in  almost  any  type.  Regardless  of  the  material 
used  as  a  filler  it  is  necessary  that  it  be  carefully  rammed  home  by  tamping,  after 
the  laying  of  every  two  or  three  courses  of  brick  in  the  fire-brick  lining. 

Grouting. — The  mixture  used  by  the  Fairbanks-Morse  Co.,  for  grouting  or  filling 
in  the  space  between  fire-brick  lining  and  shells  of  producers,  consists  of 

1  part  coal  tar; 

2  parts  sharp  sand; 
2  parts  fire-clay. 

Mix  the  sand  and  fire-clay  throughly,  and  then  add  tar  and  again  mix.  If 
the  weather  is  cold  the  ingredients  should  be  pre-heated  before  mixing,  to  assure 
assimilation.  The  sand  and  clay  should  be  dry  and  warm.  The  final  mixture 
should  be  dry  enough  to  be  taken  into  the  hands  without  sticking. 

The  brick  to  which  it  is  applied  should  be  smooth  and  lie  close.  They  should 
be  wet  in  a  thin  mixture  of  fire-clay  and  water,  being  both  dipped  and  the  mixture 
applied  with  a  brush. 

The  bricks  should  be  laid  with  a  very  thin  joint  to  prevent  skewing.  After 
laying  two  or  three  courses  of  brick  the  above  mixture  or  grouting  should  be  poured 
in  and  tamped  with  an  iron  bar. 

The  tar  mixture  should  be  covered  with  fire-clay  wherever  it  comes  in  contact 
with  the  fire,  so  that  the  tar  will  not  burn  out  before  hardening.  After  heating, 
however,  the  mixture  becomes  hard,  and  it  allows  for  the  expansion  and  contraction 
of  the  brickwork  without  cracking  or  setting,  which  faults  subtend  air  leaks  in  the 
producer. 

The  grouting  is  both  elastic  and  plastic. 

Cements. — The  following  cements  are  in  practical  use: 

FURNACE    CEMENT 

4  parts  pulverized  fire  clay; 

1  part  plumbago.     Iron  filings  or  borings  (free  from  oxidation  or  oil) . 

2  parts  peroxide  of  manganese; 
^  part  borax; 

^  part  sea  salt. 


PRODUCER   OPERATION  29 

Mix  in  thick  paste,  and  use  immediately.  Heating  gradually  when  first  using. 
Powder  thoroughly  and  tamp  home. 

HIGH    TEMPERATURE    CEMENT 

(Gaskets  and  Joints) 
1  part  white  lead; 

1  part  red  lead; 

2  parts  clean  filings  thoroughly  mixed. 

Mixture   may  be  calked   with   broad-nosed  tool. 

FIRE    CLAY    PUTTY 

Mixed  with  water  to  the  consistency  of  putty. 

Fiber  asbestos; 
Cement; 
Fire-clay. 
Or, 

5  parts  fire-clay; 

5  parts  broken  fire-brick  finely  powdered. 

Or, 

2  parts  broken  fire-brick  finely  powdered; 

2  parts  fire-clay; 

1  part  asbestos  fiber. 

The  Hawley  Down-Draft  Furnace  Co.  recommend  the  best  material  for  patch- 
ing furnaces  as  a  mixture  of  four  parts  ganister  and  one  part  fire-clay.  Also  another 
mixture  for  patching  of  two  parts  fire-clay  and  one  part  silica  sand. 

The  cements  of  the  Johns-Manville  Co.  are  good.  Fireite  is  used  most  exten- 
sively in  setting  up  furnaces  and  repairing  broken  joints  in  heating  furnaces,  ranges, 
heaters,  and  stoves.  It  adheres  readily  and  makes  a  strong  joint  on  tin  or  castings. 
It  dries  and  sets  in  a  few  hours,  and  vitrifies  under  heat  without  shrinking  or  becom- 
ing porous.  It  has  no  odor.  It  is  however  far  inferior  to  Vitrex. 

Standard  Vitrex  is  in  general  use  in  gas  and  chemical  works  for  repairing  broken 
clay  and  iron  retorts  and  pipes,  and  cementing  fittings,  connecting  pipes  and  flange- 
joints,  and  for  cementing  joints  in  stone,  wood,  and  metal.  It  is  composed  of  acid 
and  fire-proof  cementing  materials,  and  can  be  applied  with  a  trowel,  and  subjected 
to  intense  heat  it  vitrifies  without  shrinking.  It  is  not  injured  by  nitric  or  sulphuric 
acids  nor  petroleum  oils,  and  makes  an  altogether  satisfactory  cement. 

Either  of  the  cements  named  above  will  stand  all  the  heat  ordinarily  required 
in  the  places  mentioned,  the  latter  being  much  preferable.  The  writer's  personal 
experience  with  the  use  of  these  materials  has  not  gone  beyond  temperatures  2000°, 
and  they  will  no  doubt  give  satisfactory  service  up  to  this  point  and  in  all  probability 
considerably  beyond  it. 


30  GAS   PRODUCERS 

Among  the  proprietary  cements  or  dopes,  one  of  the  most  satisfactory  for  use 
with  gas  apparatus  is  "  Smooth  On,"  manufactured  by  the  Smooth  On  Manufac- 
turing Co.,  Jersey  City,  U.  S.  A.  It  may  be  used  in  making  permanent  screw-thread 
joints,  or  under  gaskets,  flanges,  etc.,  or  for  temporary  patches.  In  the  last  con- 
nection, an  efficient  temporary  patch  for  stopping  a  gas  leak  may  be  made  by  plas- 
tering the  leak  with  Smooth  On,  and  wrapping  with  cheesecloth  of  similar  fabric, 
Smooth  On  being  added  to  the  various  layers  as  the  cloth  is  applied. 

Rating. — The  rating  of  a  producer  with  American  coal  is  most  reasonable  upon 
a  basis  of  eight  pounds  per  square  foot  of  grate  surface  for  pressure  producers,  and 
ten  pounds  per  square  foot  of  grate  surface  for  suction  producers.  The  Morgan 
producer,  however,  has  been  satisfactorily  run,  it  is  said,  in  some  instances,  upon 
a  combustion  of  as  high  as  fifteen  pounds  per  square  foot  of  grate  surface.  This, 
however,  is  excessive  for  usual  practice,  and  cannot  be  generally  commended. 

Experiments  upon  the  apparatus  of  the  Loomis-Pettibone  type  go  to  show  that 
anthracite,  bituminous,  lignite,  coke,  and  even  wood,  have  about  the  same  thermal 
duty  in  combustion  per  square  foot  of  grate  surface,  their  inequality  in  calorific  value 
being  compensated  by  their  rate  of  gasification. 

In  specifications  for  rating  of  suction  gas  power  plant,  it  is  customary  to  cal- 
culate a  maximum  suction  on  the  part  of  the  engine  not  exceeding  2^  inches  of 
vacuum.  Beyond  this  duty  the  performance  of  the  engine  as  a  suction  pump  is 
not  generally  assumed  to  be  sufficiently  efficient  to  give  it  its  maximum  rating. 

Gasification  of  coal  increases  inversely  with  the  calorific  value  of  the  coal. 
(See  Fernald's  Tables.)  For  combustion  of  coal  in  the  ordinary  type  of  furnace 
or  shaft  producer,  attentative  rating  of  10  pounds  per  sq.ft.  of  grate  surface  is 
usually  an  ample  allowance;  the  horsepower  resultant  from  this  of  course  depending 
upon  the  heat  unit  content  of  the  coal  thus  gasified  and  the  efficiency  of  the  engine 
used. 

As  has  been  stated,  however,  the  increased  rating  of  combustion  on  the  part 
of  low-grade  coals  creates  a  very  even  equilibration,  so  that  the  total  number  of 
heat  units  delivered  by  various  fuels  per  unit  of  time  and  space,  is  practically  iden- 
tical, or  at  least  close  enough,  for  commercial  service. 

It  is  the  custom  of  some  engineers  to  allow  1.25  to  1.5  square  feet  of  grate 
surface  per  nominal  horsepower  for  the  lower  grades  of  bituminous  coal  and  lig- 
nites. This,  however,  merely  maintains  the  ratio  of  space  to  weight  of  fuel  already 
indicated.  It  does  not,  however,  include  the  element  of  time  or  rapidity  of  com- 
bustion or  combination.  This  is  most  likely  a  mistake,  especially  where  the  low- 
grade  fuel  possesses  high  volatile  content  and  high-flame  propagation,  when  the 
high  speed  of  gasification  more  than  compensates  for  its  thermal  content  per  unit 
of  weight. 

It  is  claimed  in  defense  of  this  increased  area  that  the  grate  surface  allowed 
is  not  co-ordinate  with  gasification,  by  reason  of  the  total  thermal  liberation  of 
heat  units,  or  nominal  horsepower  supplied,  but  in  order  to  accommodate  the  rapid 
increase  of  ash  both  in  its  rate  of  formation  and  the  large  bulk  incident  to  low- 
grade  fuels. 

On  the  other  hand,  however,  it  must  be  remembered  that  low-grade  fuel  con- 
tains a  large  quantity  of  binding  ash,  moisture,  and  other  neutrilent,  all  of  these 


PRODUCER   OPERATION  31 

subtending  low-flame  temperature.  Hence  where  combustion  occurs  over  a  rela- 
tively large  area  by  reason  of  the  heat  insulation  and  ventilation  of  the  foreign 
matter,  conditions  of  radiation,  etc.,  the  fuel  bed  temperature  is  extremely  low, 
too  low  in  many  instances  for  the  proper  rate  or  temperature  for  gasification. 
Hence,  in  order  to  obtain  the  temperature  of  gasification,  it  is  sometimes  necessary 
to  concentrate  the  combustion  area.  So  it  is  doubtful  whether  the  above  rating 
should  ever  be  exceeded.  If.  however,  it  should  be,  such  an  arrangement  should 
only  be  for  the  disposition  of  the  ash,  when  it  should  be  remembered  that  many 
of  the  lignites  and  lower  grade  fuels  are  not  necessarily  richer  in  ash  than  coals  of 
a  higher  grade,  but  that  they  form  their  ash  more  rapidly  by  reason  of  the  high  rate 
of  combustion  and  the  distillation  of  the  moisture  and  volatile  binding. 

Within  certain  limits  (with  good  grade  fuels),  fixed  by  the  economy  of  con- 
struction and  convenience  of  operation,  the  latter  being  principally  stoking,  the  lower 
the  gasification  duty  per  unit  of  grate  surface  in  all  fuel  bed  producers,  the  less  the 
clinker  and  other  difficulties  of  operation.  This  is  due  to  condition  of  heat  propa- 
gation, blast  distribution,  and  other  contingencies.  One  of  the  most  successful 
producers  operating  to-day  is  dcing  a  gasification  duty  of  only  four  pounds  of  coke 
per  square  foot  of  grate  surface. 

Load  Factor. — Load  factor  is  usually  defined  as  the  ratio  of  average  load  to 
maximum  capacity  or  demand.  The  efficiency  of  suction  producers  varies  but 
little  upon  various  load  factors  so  long  as  these  remain  below  the  limit  of  maximum 
capacity.  Any  lack  of  efficiency  shown  by  a  plant  on  low  load  factors  is  due  to 
the  low  efficiency  of  the  engine  beneath  its  rated  capacity,  and  not  to  the  producer. 

The  operation  of  the  producer  at  various  load  factors  need  not  be  changed  as 
much  where  an  exhauster  is  interposed  as  where  the  pumping  is"  dependent  upon 
the  engine.  It  is  generally  expedient,  however,  in  both  cases  to  thin  the  depth 
of  the  fuel  bed  upon  low  loads,  and  conversely  to  increase  the  depth  of  fuel  beds 
upon  heavy  loads.  This  condition  has  to  do,  however,  largely  with  the  question 
of  time  contact. 

The  area  of  the  producer  is  not  materially  effected  in  these  calculations,  it 
being  not  only  practical  but  extremely  efficient  to  gasify  at  a  very  slow  rate  per 
unit  of  cross-section.  It  is  of  course  necessary  to  gasify  at  a  sufficient  rate  to  main- 
tain the  proper  temperature  for  dissociation  and  reaction,  hence  a  minimum  limit 
of  from  4  to  5  pounds  of  coal  gasified  to  the  square  foot  of  cross-section  should  be 
maintained,  while  the  maximum  limit  for  most  coals  should  not  exceed  15  pounds 
per  square  foot  of  cross  section. 

Up-  and  Down-draft  Types. — American  practice  shows  a  division  line  between 
up-  and  down-draft  producers,  the  line  of  demarcation  being  the  volatile  contents 
of  coal  analysis.  This  line  appears  to  be  about  20%  of  volatile  matter,  and  above 
that  down-draft  apparatus  is  necessary  by  reason  of  its  recovery  of  hydrocarbons 
and  their  fixing  into  a  permanent  gas.  Below  that,  up-draft  apparatus  is  sufficiently 
satisfactory,  and  offers  a  more  simple  operation  and  cheap  construction. 

Messrs.  R.  D.  Wood  &  Co.,  who  are  the  manufacturers  of  down-draft  apparatus, 
make  the  following  statement  concerning  the  operation  of  producers  of  this  class: 
"  For  any  length  of  continuous  operation  such  apparatus  requires  obviously  a  very 
good  fuel,  as  coals  with  low  sulphur  and  a  refractory  low  ash.  It  would  fail  with 


32  GAS   PRODUCERS 

many  ordinarily  available  fuels  which  can  readily  be  gasified  in  the  usual  up-draft 
type  of  producer." 

Suction  and  Pressure  Types. — The  advantage  of  suction  producers  over  pres- 
sure producers  lies  under  three  headings: 

First.  There  is  less  tendency  in  the  suction  producer  to  channeling  distribu- 
tion of  gases  within  the  producer  being  more  uniform. 

Second.  The  gasification  of  the  fuel  occurs  more  rapidly  and  readily  below, 
rather  than  above  atmospheric  pressure.  This  is  instanced  in  a  coal  gas  retort 
and  a  coke  oven,  where  the  volume  of  gas  increases  rapidly  in  its  delivery  under 
increased  suction. 

Third.  The  production  of  carbon  monoxide  is  much  more  rapid  under  con- 
ditions of  suction  than  it  is  by  pressure;  this  is  probably  by  reason  of  certain  con- 
ditions of  mass  action,  notably,  perhaps,  that  the  combined  gas  is  withdrawn  rapidly 
and  immediately  upon  its  formation,  and  by  its  absence  prevents  the  formation  of 
any  neucleus  or  obstacle  to  the  contact  and  union  of  the  uncombined  elements, 
namely,  carbon  and  oxygen. 

In  this  way  the  rate  of  its  union  or  combination  remains  uniform,  whereas 
under  conditions  of  mass  action  under  ordinary  circumstances,  chemical  action 
becomes  materially  slower  in  combination,  by  reason  of  the  interposition  of  the 
combined  matter  already  formed. 

In  pressure  producers  a  constant  pressure  (about  one-half  inch  of  water)  is 
maintained  on  the  gas  main,  and  this  regulated  by  the  small  steam  valve  on  the 
blower,  which  can  be  changed  from  a  full  head  of  gas  to  a  complete  stop,  or  vice 
versa,  by  a  few  turns  of  the  hand.  When  blast  is  entirely  off,  the  producer  will 
remain  hot  and  ready  for  business  at  a  few  minutes'  notice,  for  several  days,  without 
any  fuel  being  fed  into  it. 

The  chief  distinction  between  suction  and  pressure  producers  may  be  marked 
by  the  line  between  power  and  fuel  purposes.  There  is  scarcely  a  doubt  but  that 
the  formation  of  producer  gas  occurs  more  readily  and  rapidly  below  than  above 
atmospheric  pressure,  and  the  coal  is  more  rapidly  gasified.  As  a  matter  of  fact, 
suction  producers  would  entirely  supersede  pressure  producers  were  it  not  for  the 
impossibility  of  handling  gases  at  a  high  temperature  through  the  medium  of  an 
exhauster. 

The  Brewster  Engineering  Company  has  designed  an  exhauster,  water  jacketed 
throughout,  which  is  supposed  to  have  a  capacity  for  handling  gases  up  to  1200°  F., 
but  even  with  this  apparatus  it  would  be  necessary  to  materially  lower  the  tem- 
perature of  the  gases  Leaving  the  producer  before  admitting  them  to  the  exhauster, 
and  hence  a  considerable  amount  of  sensible  heat  would  be  lost  in  any  fuel  opera- 
tion. This  of  course  is  necessary  in  any  event  in  a  power  plant  where  the  gas  must 
be  both  cleansed  and  condensed  prior  to  its  entry  into  the  engine. 

Where  suction  producers  are  used  for  the  production  of  any  large  amount  of 
gas  they  should  be  connected  in  upon  a  header  or  bus-pipe  with  interposing  valves, 
so  that  the  load  upon  each  one  could  be  regulated.  This  header  acts  as  an  equalizer 
and  can  be  in  turn  connected  with  the  exhauster,  and  the  valves  aforesaid  may  be 
so  set  as  to  prevent  "  robbing." 

It  is  not  advisable  to  use  single  suction  units  larger  than  8  or  10  ft.  inside  diam- 


PRODUCER   OPERATION  33 

eter,  as  after  that  the  problem  of  hand  stoking  and  the  maintenance  of  the  fire  in 
proper  condition  becomes  impractical.  Two  or  more  suction  producers  should 
never  be  connected  to  any  apparatus  without  the  intervention  of  the  equalizing 
pipe  and  exhauster,  the  latter  being  preferably  of  the  water-seal  or  blow-back  type. 
Single  suction  producers  may  occasionally  be  connected  direct  to  the  suction  pipe 
of  an  engine,  although  this  arrangement  is  less  efficient  than  that  of  an  exhauster. 

According  to  one  manufacturer,  the  calorific  power  or  heat  value  per  cubic  foot 
of  suction  producer  gas  may  average  15%  lower  than  pressure  gas,  having  less  CO 
and  H,  but  requiring  less  air  for  combustion. 

This  observation  is,  however,  probably  due  to  the  attenuation  of  the  gas  under 
suction  or  change  of  vapor  tension.  Understanding  conditions,  in  the  opinion  of 
the  writer,  there  should  be  little  or  no  difference,  or  if  any,  it  would  be  in  favor  of 
the  suction  apparatus;  hence,  where  an  exhauster  is  interposed  there  would  be 
practically  equal  calorific  power  upon  the  plus  side. 

Water-seal  Producers. — The  water  seal  producer  should  be  differentiated  from 
that  of  the  grate  type  by  reason  of  the  following  characteristics:  The  water-seal 
producer  is  particularly  available  for  units  of  large  nature  and  where  the  gas  is  to 
be  used  for  furnace  or  purely  fuel  purposes.  This  is  for  two  reasons:  First',  the 
accessibility  in  stoking  and  the  easy  removal  of  large  quantities  of  ash.  -Second, 
because  such  installations  are  usually  placed  in  more  or  less  open  places,  where  the 
leakage  occurring  through  the  blowing  or  bubbling  of  the  seal  is  not  objectionable. 

Where  the  producer  is  installed  for  power  purposes,  however,  the  water  seal 
is  not  advisable,  for  the  reason  that  the  varying  content  of  ash,  that  is  to  say,  the 
increase  or  decrease  in  depth  of  the  ash  bed,  makes  the  regulation  of  the  fire  and 
the  resultant  uniformity  of  the  gas  a  very  difficult  proposition.  Hence  where  an 
absolutely  uniform  gas  is  desired,  as  in  power  propositions,  the  grate  producer 
should  be  invariably  used.  Producers  of  the  Morgan  type  are  particularly  adapted 
to  this  (water  seal)  character  of  work. 

The  principal  advantage  of  a  water-seal  producer  lies  in  the  opportunity  it 
affords  for  continuous  running,  it  being  possible  to  clean  fires  and  withdraw  ashes 
without  letting  down  or  stopping  the  machine. 

Water-seal  producers  may  also  be  operated  in  combination  with  grates,  which 
enables  a  better  regulation  of  the  fuel  bed. 

Steam  Supply. — The  necessary  steam  pressure  for  operating  the  steam  under 
the  producer,  says  Sexton,  necessarily  depends  upon  the  size  of  the  producer,  the 
nature  of  the  fuel,  the  depth  of  the  fire  bed,  and  the  kind  of  gas  required.  The 
pressure,  however,  varies  between  30  and  60  pounds  per  square  inch,  the  latter  being 
most  efficient  for  use  with  the  air  inductor,  although  this  pressure  should  not  be 
so  great  as  to  create  channeling  through  the  fire  bed.  Where  high  pressures  are 
used,  they  must  be  offset  by  very  considerable  reduction  of  the  orifice  and  the  use 
of  proper  baffles  within  the  producer. 

The  amount  of  steam  used  in  a  producer  varies  from  £  Ib.  per  pound  of  coal 
gasified,  which  is  about  the  minimum,  to  2.5  Ibs.,  as  exemplified  by  the  Mond  by- 
product recovery  system.  The  average  will  probably  be,  in  average  suction  or 
pressure  producers,  in  commercial  practice,  about  0.7  Ibs.  to  1  Ib.  In  the  St.  Louis 
test  the  weights  of  steam  varied  from  0.3  to  0.6  Ibs.  per  pound  of  Pocahontas  coal. 


34  GAS   PRODUCERS 

The  best  proportions  of  steam  and  air  cannot  be  rigidly  fixed,  the  more  steam 
that  is  used  the  better,  until  a  limit  is  reached,  this  limit  depending  mainly  upon 
the  amount  of  heat  that  is  available  for  decomposing  the  steam  without  unduly 
cooling  the  producer,  and  this  will  depend  on  the  loss  of  heat  in  the  producer  itself. 
The  average  proportions  when  a  producer  is  working  well  are  about  10  parts  steam 
and  90  parts  air  by  volume,  rising  sometimes  to  12.5  parts  of  steam  to  87. 5  parts 
air,  but  rarely  passing  beyond  this.  Taking  10  per  cent  of  steam  by  volume  as 
being  a  good  working  proportion,  this  will  be  about  6  per  cent  of  steam  by  weight, 
and  about  one-fifth  of  the  carbon  will  be  burned  by  steam  and  four-fifths  by  air. 

Assuming  6  per  cent  of  steam  by  weight,  it  is  very  easy  to  calculate  the  amount 
of  fuel  that  will  be  consumed.  Since  1  Ib.  of  carbon  will  combine  with  1.33  Ibs. 
oxygen  to  form  carbon  monoxide,  and  air  contains  23  per  cent  by  weight  of  oxygen, 

1  33 X 100 
the   amount  of  air  required  to   burn   1   Ib.   of   carbon  will  be    -  —  =  5.8  Ibs., 

aO 

therefore  1  Ib.  of  air  will  burn  —  =  0.171  Ib.  of  carbon. 

5.8 

One  pound  of  carbon  in  decomposing  steam  will  also  combine  with  1.33  Ibs. 
of  oxygen,  and  this  will  be  contained  in  1.49  Ibs.  of  steam;  therefore  1  Ib.  of  steam 

will  burn  T"7^==0-67  Ib.  of  carbon,  so  that  for  100  Ibs.  of  the  gaseous  mixture 
j.  •  ^ty 

94  Ibs.  of  air        =0.171X94  =  16  Ibs.  of  carbon  burned  by  air. 
6    "      "  steam  =0.67   X6   =  4     "     "         "  "        by  steam. 

100  Ibs.  of  steam  and  air         =20  Ibs.  of  carbon  burned  by  mixture. 

If  loss  of  heat  in  the  producer  could  be  guarded  against,  a  much  larger  propor- 
tion of  steam  could  be  used.  One  engineer  of  large  experience  has  stated  to  the 
author  that  seven  per  cent  by  weight  is  the  maximum  amount  of  steam  which  should 
be  used  in  an  ordinary  steam-blown  producer. 

Assuming  the  proportions  above  given  to  be  correct,  it  is  easy  to  ascertain  what 
amount  of  steam  will  be  required  to  work  a  gas  producer.  In  all  such  calculations 
only  the  fixed  carbon  of  the  fuel  must  be  taken  into  account,  as  all  volatile  matter 
will  be  expelled  before  the  residue  comes  under  the  action  of  the  air  and  steam. 
The  amount  of  fixed  carbon  in  fuel,  and  the  amount  of  gas  given  off  by  the  fuel, 
should  therefore  always  be  determined.  The  amount  of  steam  required  will  be  6  Ibs. 
for  each  20  Ibs.  of  carbon  burned,  or  0.3  Ib.  of  steam  for  each  pound  of  carbon. 

Assuming  the  coal  used  to  yield  60  per  cent  of  fixed  carbon,  0.6x0.3  =  0.18 
Ib.  of  steam  will  be  required  for  each  pound  of  coal  consumed.  To  be  on  the  safe 
side,  the  boilers  should  be  capable  of  supplying  two  or  three  times  this  amount. 

Each  pound  of  carbon  will  require  5.8  Ibs.  of  air,  or  1  Ib.  of  coal  of  the  com- 
position assumed  will  require  3.48  Ibs.  of  air.  As  1  Ib.  of  air  under  normal  condi- 
tions of  pressure  and  temperature  occupies  12.36  cubic  feet,  the  volume  of  air  required 
will  be  58.1  cubic  feet  for  each  pound  of  carbon,  or  34.9  cubic  feet  for  each  pound 
of  coal  consumed.  The  steam  should  be  supplied  at  a  high  pressure,  60  Ibs.  to  75 
Ibs.  being  usually  used. 


PRODUCER   OPERATION 


35 


For  the  purpose  of  introducing  into  the  producer  the  steam  with  air  supply, 
the  jet  blower  is  simple,  compact,  and  cheap,  but  it  requires  intelligent  us».  Its 
advantages  are  greater  when  the  gas  is  much  cooled  before  use;  less  with  a  close 
connection  of  producer  and  furnace,  and  with  soft  coals  than  with  carbonized  fuels. 
The  use  of  steam  increases  the  fuel  by  adding  H  to  the  gas,  reduces  the  inert  N,  raises 
calorific  power,  lowers  exit  temperature  of  gases  and  retards  clinkering.  It  does 
not  produce  more  heat,  simply  transfers  it  from  the  generator  to  the  furnace,  where 
it  is  burned  by  the  potential  heat  value  of  the  H  instead  of  the  less  efficient  means 
of  greater  sensible  heat  in  the  gas. 

Too  much  steam,  however,  reduces  the  combustible  in  the  gas  and  lowers  calorific 
power,  reducing  the  amount  of  CO  and  increasing  C02,  and  H.  Jenkin  reports  analyses 
as  follows: 


Volume  %. 

EXCESS  OP  STEAM. 

Moderate. 

Great 

C02 
CO 

5.30 
23.50      . 

8.90 
16.40 

CH4 
H 

3.30 
13.14 

2.55 
18.60 

In  gasification  of  coke  there  is  often  strong  tendency  to  clinker,  and  use  of  more 
steam  may  commend  itself. 

Steam  Temperature. — The  effect  of  temperature  on  the  reaction  between 
steam  and  C  is  of  fundamental  importance,  says  Wyer,  and  data  showing  the  effects 
of  different  temperatures  are  given.  The  figures  were  obtained  from  the  experi- 
ments of  Dr.  Bunte.  The  table  shows  conclusively  that  it  is  very  desirable  to  keep 
the  decomposition  zone  at  a  high  temperature. 

EFFECTS  OF  TEMPERATURE  ON  ACTION  OF  STEAM 


Temperature,  C. 

Percentage  of 
Steam 
Decomposed. 

COMPOSITION  OF  GAS  BY  VOLUME. 

H 

CO 

CO'2 

674 

8.8 

65.2 

4.9 

29.8 

758 

25.3 

65.2 

7.8 

27.0 

838 

41.0 

61.9 

15.1 

22.9 

954 

70.2 

53.3 

39.3 

6.8 

1010 

94.0 

48.8 

49.7 

1.5 

1125 

99.4 

50.9 

48.5 

0.6 

An  investigation  on  the  use  of  steam  in  gas-producer  practice  was  undertaken 
by  W.  A.  Bone  and  R.  V.  Wheeler,  and  embodied  in  a  paper  read  in  1907  before 
the  British  Iron  and  Steel  Institute.  The  producers  selected  for  the  trials  were  of 
the  Mond  type.  On  leaving  the  producers,  the  hot  gas  passed  through  the  super- 
heaters, around  which  the  air  and  steam  forming  the  blast  traveled,  in  the  reverse 


36 


GAS   PRODUCERS 


direction,  through  annular  space  between  the  inner  gas  main  and  an  outer  jacket. 
No  recuperation  was  attempted  in  the  air  heating  towers.  The  steam  used  for 
saturating  the  air  blast  was  partly  exhaust  steam  (in  the  trials  at  60°  and  65°  wholly 
so)  and  partly  live  steam.  The  efficiency  is  based  on  the  net  calorific  values  of  the 
coal  and  gas.  It  includes  the  coal  burned  under  the  boiler  for  raising  steam  for  the 
blast,  plus  that  required  for  the  blower  engine;  also  the  coal  equivalent  for  any 
mechanical  work  required  for  cooling  and  washing  the  gas  for  engines.  The  boiler 
had  an  efficiency  of  58  per  cent. 


Steam  saturation  temperature.  .  .                   .    . 

60° 

65° 

70° 

75° 

80° 

Mean  percentage  composition  of  gas  obtained  : 
Co2.  .  .                        

5.25 

6.95 

9.15 

11.65 

13  25 

CO  

27.30 

25.40 

21.70 

18.35 

16  05 

H2.  . 

16.60 

18.30 

19.65 

21.80 

22.65 

CH4.  .  .  . 

3.35 

3.40 

3.40 

3.35 

3.50 

N,  .  .  .                              

47.50 

45.90 

46.10 

44.83 

44.55 

Total  combustibles.                                 ... 

47.25 

47.10 

44.75 

43  50 

42  20 

Calorific  value  of  gas  (gross).  .  . 

46  77 

46.74 

44.74 

43  37 

42  73 

Calories  at  32°  F   (net).    .  . 

43  60 

43  32 

41  .14 

39  65 

38  69 

Yield  of  gas,  cubic  feet  per  ton  

138,250 

134,400 

141,450 

145,800 

147,500 

Pounds  of  steam  in  blast  per  pound  of  coal 
gasified.  .  .            

0.45 

0.55 

0.80 

1.10 

1  55 

Percentage  of  steam  decomposed  

87.4 

80.0 

61.4 

52.0 

40  0 

Cubic  feet  of  air  at  32°  F.  and  30"  in  blast 
per  pound  carbon  gasified.    .          

36.95 

34.9 

36.8 

36.9 

37  1 

Ammonia  in  gas  as  pound  of  NH4SO4  per  ton 
of  coal  

39.0 

44.7 

51.4 

65.25 

71.8 

Efficiencies: 
(1)  Including  steam  for  blower  engine.  ..  . 
(2)  Including  steam  for  blower  engine  and 
washers  

0.778 
0.715 

0.750 
0.687 

0.727 
0.660 

0.701 
0.640 

0.665 
0  604 

St.  John  Recording  Steam  Meter. — The  principle  on  which  the  meter  operates 
is  that  with  a  uniform  difference  of  pressure  on  two  sides  of  an  orifice  through 
which  steam  is  flowing,  the  quantity  of  steam  passing  bears  a  direct  relation 
to  the  size  of  the  orifice.  In  this  meter  steam  enters  at  the  bottom,  and  follow- 
ing the  direction  of  the  arrows  leaves  at  the  top.  In  the  section  shown  S  is  a  brass 
bushing  screwed  into  the  portion  of  the  casting  which  separates  the  spaces  A  and 
B.  A  brass  valve  V  is  shown  with  tapered  shank  or  plug  supported  at  top  and 
bottom,  running  in  guides  in  the  castings.  This  valve  operates  in  such  manner  that 
when  in  its  lowest  position  the  top  of  the  tapered  plug  fits  closely  within  the  brass 
bushing  or  seat,  and  the  lip  of  the  valve  rests  on  the  seat  and  no  steam  can  flow. 
When  the  valve  is  raised,  the  space  between  the  tapered  plug  and  the  seat  increases 
from  zero  to  a  maximum  when  the  valve  is  in  its  highest  position  and  the  rate  of 
increase  depends  upon  the  taper  of  the  plug. 

The  space  between  the  tapered  plug  and  the  seat  S  is,  then,  the  orifice  through 
which  the  steam  flows  and  the  size  of  the  orifice  varies  as  the  plug  rises  or  falls, 
which  occurs  with  the  increase  or  decrease  in  the  quantity  of  steam  flowing. 
The  weight  of  the  plug  is  such  that  the  pressure  beneath  the  plug  in  space  A 
must  be  about  two  pounds  greater  than  in  space  B  in  order  to  raise  the  valve  or 


PRODUCER   OPERATION 


37 


keep  it  raised  off  the  seat  and  floating  in  the  current  of  steam.  The  weight  of  the 
valve  remaining  the  same  at  all  times,  the  difference  in  pressure  on  the  two  sides 
of  the  orifice  of  about  two  pounds  per  square  inch  will  remain  the  same  no  matter 
what  position  the  valve  may  occupy. 

The    means   by    which    the   size    of   the    orifice   varies   automatically    with    the 


FIG.  11. — Section  of  the  St.  John  Steam  Meter. 

draft  of  steam  through  the  meter,  and  the  means  by  which  a  uniform  difference 
of  pressure  is  maintained  at  all  times  on  the  two  sides  of  the  orifice,  is  thus  shown. 
The  taper  of  the  plug  is  such  that  the  amount  of  steam  passing  through  the 
orifice  per  hour  is  directly  proportional  to  the  rise  of  the  valve.  That  is,  if  1000 
pounds  of  steam  will  pass  in  one  hour  when  the  valve  is  raised  one  inch,  then  when 


38 


GAS   PRODUCERS 


the  valve  is  raised  two  inches  2000  pounds  will  pass,  and  with  a  raise  of  one-half 
inch  500  pounds  per  hour  will  pass.  Thus  the  rise  of  the  valve  is  a  direct  indica- 
tion of  the  quantity  of  steam  flowing  through  the  meter  per  hour. 


FIG.  12. — View  of  the  St.  John  Steam  Meter. 

To  transfer  this  motion  to  the  pencil-arm  outside  of  the  meter  casing,  which 
carries  the  pencil  and  pointer,  a  lever  arm  inside  the  casing  is  supported  at  the 
center  of  rotation  by  a  spindle,  and  is  connected  in  proper  manner  to  the  upper 


PRODUCER   OPERATION  3Q 

valve  spindle  at  N.  The  horizontal  spindle  at  0  projects  through  the  meter  casing 
to  support  the  pencil-arm,  and  is  provided  with  a  small  stuffing  box  to  prevent 
leakage  of  steam.  The  pencil-arm  is  set  at  such  an  angle  with  relation  to  the  inside 
lever  arm  that  when  the  valve  is  on  its  seat  the  pointer  will  be  over  the  zero  of 
the  dial  scale.  Above  the  pencil  held  by  the  pencil-arm  is  a  second  pencil  in  a 
holder  attached  to  the  register  frame,  which  may  be  adjusted  horizontally  and  which 
should  be  set  so  that  it  is  directly  above  the  moving  pencil  and  so  that  the  lines 
drawn  by  the  two  pencils  will  coincide  when  the  valve  is  on  its  seat  and  the  pointer 
at  zero.  This  line  drawn  by  the  stationary  pencil  is  called  the  base  line. 

The  vertical  movement  of  the  valve  thus  produces  a  horizontal  movement  of 
the  pointer  over  the  dial  and  of  the  pencil  over  the  paper  chart.  With  a  proper 
scale  engraved  upon  the  brass  dial  in  accordance  with  the  calibration  of  the  meter, 
the  rate  of  flow  of  steam  through  the  meter,  either  in  pounds  per  hour  or  in  horse- 
power, may  be  read  from  the  dial  at  any  instant.  At  the  same  time,  with  a  proper 
scale  of  equal  divisions  marked  upon  the  length  of  the  chart  to  represent  hours, 
and  a  uniform  vertical  movement  of  the  chart  upward  under  the  pencil  at  such  a 
rate  that  hour  divisions  marked  on  the  paper  will  pass  under  the  pencil  at  hourly 
intervals  of  time,  the  pencil  will  face  a  line  the  distance  of  which  from  the  base- 
line will  remain  as  a  record  of  the  rise  of  the  valve  and  hence  of  the  rate  of  flow 
of  steam  at  all  times  throughout  the  day.  This  line,  drawn  by  the  moving  pencil, 
is  called  the  steam  line.  The  motion  of  the  chart  is  produced  by  two  brass  rollers 
held  against  each  other  by  springs,  between  which  the  chart  passes,  and  which  are 
operated  by  clockwork. 

Every  meter  is  calibrated  under  working  conditions,  the  steam  after  passing 
through  the  meter  being  condensed  by  means  of  a  surface  condenser  and  the  water 
weighed  in  a  tank  on  scales.  The  brass  indicator  scale  is  cut  after  the  meter  is 
calibrated  and  the  rate  of  the  meter  determined. 

Sargent  Steam  or  Compressed  Air  Meter. — The  demand  for  a  device  which 
would  accurately  record  or  indicate  the  quantity  of  steam  passing  through  a  pipe 
has  long  been  recognized  by  engineers.  There  are  numerous  ways  of  calculating 
the  rate  of  flow  of  steam  through  orifices  and  pipes,  but  the  conditions  are  usually 
such  that  these  calculations  do  not  conform  with  reason.  Variations  in  the  moisture 
contained  in  steam,  different  degrees  of  superheat,  and  the  skin  friction  of  the  pipe, 
are  factors  which  introduce  errors  in  calculations.  The  most  reliable  method  of 
determining  the  quantity  of  steam  passing  through  a  pipe  is,  of  course,  to  condense 
the  steam  and  weigh  the  condensate. 

In  view  of  the  above  mentioned  demand,  the  Sargent  steam  and  compressed 
air  meter  was  designed  and  placed  upon  the  market.  The  device  indicates  the 
quantity  of  steam  flowing  through  a  pipe,  irrespective  of  the  pressure,  and  is  said 
to  be  accurate  within  2%. 

The  valve  of  the  meter  is  cone  shaped  in  order  to  attain  a  large  movement  for 
complete  opening  of  the  valve.  The  raising  and  lowering  of  the  valve  indicates 
volume,  and  a  Bourdon  spring,  carried  by  a  valve  stem  in  the  lower  part  of  the 
meter,  carries  a  needle  which  is  given  vertical  movement  by  the  valve  opening, 
and  lateral  motion  by  the  pressure  produced  on  the  Bourdon  spring.  This  needle 
moves  before  a  dial  which  has  been  calculated  and  laid  out  from  actual  test. 


40 


GAS   PRODUCERS 


FIG.  13. — The  Sargent  Steam  Meters. 


PRODUCER  OPERATION  41 

In  testing,  the  meter  is  placed  on  a  steam  line  which  leads  to  a  3000  h.p. 
condenser  close  by.  The  per  cent  of  moisture  in  the  steam  is  determined  by  a 
throttling  steam  calorimeter,  and  is  usually  found  to  be  about  2%.  Several  tests 
with  various  valve  openings  and  pressures  are  taken,  and  after  a  complete  log  is 
taken,  a  dial  based  on  the  test  log  is  laid  out.  When  such  means  are  adopted  for 
testing  the  device,  its  accuracy  can  be  fully  relied  upon. 

It  is  used  for  testing  engines  where  surface  condensers  are  not  available  for 
testing  the  capacity  of  boilers  and  for  measuring  the  amount  of  steam  used  in  each 
department  of  industrial  plants.  It  is  used  by  many  who  sell  steam,  and  by  others 
who  buy  steam.  By  placing  it  on  the  steam  pipe  to  your  engine  you  can  tell  at  a 
glance  the  horsepower  the  engine  is  developing  or  the  pounds  of  steam  required  to 
carry  your  load. 

If  the  meter  is  located  in  a  steam  header  and  the  coal  is  weighed,  the  pounds 
of  water  evaporated  per  pound  can  be  determined  by  simple  inspection,  and  the 
cost  of  evaporating  a  pound  of  water  with  different  grades  of  coal  is  readily  deter- 
mined without  ^he  expense  of  elaborate  tests. 

The  Sargent  steam  meter  indicates  the  quantity  of  steam,  or  horsepower, 
flowing  through  just  as  a  steam  gauge  indicates  the  pressure  on  the  boiler,  and  if  the 
steam  from  the  meter  is  condensed  and  weighed,  the  indications  will  check  irre- 
spective of  the  pressure.  Each  meter  is  calibrated  separately,  and  the  dial  is  made 
from  the  results  obtained. 

The  meters  are  tested  with  commercially  dry  steam  and  when  used  to  measure 
steam  of  the  same  quality  are  always  reliable.  A  very  wet  steam  or  slugs  of  water 
have  no  injurious  effect  upon  the  workings  of  the  meter  and  cannot  derange  the 
working  parts. 

The  location  of  the  meter  may  be  anywhere  in  the  steam  line,  preferably  close 
to  the  boilers,  where  the  flow  is  uniform.  If  placed  near  an  engine,  a  tank  or  drum 
holding  two  or  three  times  the  capacity  of  the  cylinder  should  be  inserted  between 
the  meter  and  the  engine.  In  a  long  run  of  pipe,  where  there  is  liable  to  be  con- 
siderable condensation,  a  separator  before  the  meter  should  be  inserted  if  very 
accurate  results  are  desired. 

Grates. — Grates  for  producers  may  be  classified  in  general  under  two  heads. 
A.  Those  depending  upon  the  natural  angle  of  repose  of  the  fuel.  B.  Those  of  the 
grid  type,  either  cast  as  in  the  Herringbone  and  shaking  grates,  or  straight  bars  of 
steel.  Their  respective  merits  and  disadvantages  stated  briefly  are  as  follows: 

Probably  the  best  universal  grate,  and  that  most  generally  adapted  to  the 
widest  range  of  fuels,  consists  of  a  number  of  simple  wedge-shaped  cast-iron  or  steel 
bars  (the  former  being  most  cheaply  replaced),  these  bars  being  loosely  laid  on  two 
or  more  girders  intersecting  the  diameter  of  the  producer. 

Square  bars  may  also  be  used.  The  ease  and  cheapness  with  which  the  bars 
may  be  replaced  form  their  chief  advantage,  in  addition  to  which  they  are  fairly 
efficient  in  their  distribution  of  draft.  Distance  blocks  may  or  may  not  be  used 
for  keeping  them  in  place,  as  conditions  require. 

The  admission  of  steam,  with  blast  beneath  the  grate  bars,  creates,  of  course, 
a  material  saving  in  their  life.  This  is  also  the  case  where  water  is  maintained  in 
the  ash  pit.  It  should  be  borne  in  mind,  however,  that  when  water  is  carried  to 


42 


GAS   PRODUCERS 


FIG.  14. — Grid  Type  Grate  for  Air  Producer. 


SECTION  A-A 

FIG.  15.— Top  View  of  Grate. 


FIG.  16.— Section  of  Grate  Bars. 


PRODUCER   OPERATION  43 

the  ash  pit,  the  endothermic  agent  is  materially  increased,  the  evaporation  becom- 
ing as  high  as  0.3  Ib.  of  water  per  pound  of  coal,  gasified,  where  the  heats  carried 
are  high. 

Angle  of  Repose  Grates.  The  angle  of  repose  grates,  under  which  class  come  not 
only  the  bar  grates  interspaced,  but  the  step  grates,  ring  grates,  conical  grates,  and 
inverted  grates,  which  are  used  more  especially  in  Germany  in  connection  with  low 
grade  fuels.  They  have  a  single  advantage  of  not  clogging  easily,  and  being,  when 
properly  designed,  more  accessible  and  readily  cleaned.  This  constitutes  a  material 
factor  where  the  fuel  used  is  of  a  fluxing,  fining,  or  highly  resinous  nature,  wherein 
the  voids  of  an  ordinary  grate  tend  to  plug  or  clog,  while  in  the  first  and  last  classes 
the  grates  are  clogged  by  the  viscous  matter,  in  the  case  of  some  fuels  not  dissimilar 
to  molten  asphalt. 

As  a  disadvantage,  however,  the  repose  grate  is  exceedingly  uneconomical, 
the  leakage  of  fuel  through  them  being  excessive,  especially  if  not  manipulated 
with  the  greatest  care.  This  tends  to  make  them  impractical,  except  with  a  more 
or  less  resinous  or  coking  fuel,  which  tends  to  bridge  or  arch  over  their  spacing  and 
retain  the  coal  from  "  running." 

Another  questionable  disadvantage  is  the  fact  that  the  repose  grates  blank 
a  large  surface  of  the  active  area  of  the  producer;  also  it  converges  or  baffles  to 
some  extent  the  incoming  air,  and  it  is  therefore  a  question  whether,  on  the  up- 
draft  producer,  its  diffusion  is  as  complete  or  thorough  as  that  of  the  grid  type. 

Grid-Type  Grates.  The  grid  grates,  especially  the  better  design,  have  a  more 
universal  and  uniform  distribution  of  voids  over  the  total  cross-section  of  the  pro- 
ducer. Theoretically  they  are  unquestionably  satisfactory,  but  practically  these 
grates  stop  up  by  reason  of  the  small  size  of  their  apertures  and  voids,  and  in  actual 
practice,  particularly  where  the  fuel  is  either  resinous  or  fines  (in  other  words,  in  any 
other  than  a  coking  coal),  a  large  percentage  of  the  voids  are  continually  stopped, 
and  hence  a  considerable  portion  of  the  active  grate  surface  is  blanked. 

So  far  is  this  true  that  there  are  several  grate  manufacturers  supplying  boiler 
furnaces  who  make  guarantees  of  non-clinkering  on  the  simple  fact  that  they  are 
able  to  keep  the  voids  in  their  grates  open,  and  that  where  the  voids  are  clear  and 
the  draft  equal  and  uniform  in  pressure  and  volume  throughout  the  entire  active 
surface  of  the  furnace,  no  clinker  will  result. 

As  a  matter  of  fact,  we  are  aware  that  inequality  in  temperature  is  the  primal 
cause  of  clinkering  in  any  furnace  or  producer,  and  moreover  we  know  that  such 
inequality  is  subtended  by  unequal  draft  and  the  resultant  combustion  area. 

However,  the  maintaining  of  these  voids  in  a  clear  and  free  condition  in  grates 
of  the  grid  type  is-  theoretically  a  satisfactory  arrangement,  but  practically  is 
extremely  difficult. 

Shaking  Grates.  An  illustration  of  the  shaking  grate  is  the  one  manufactured 
by  the  New  England  Roller  Grate  Co.,  of  Springfield,  Massachusetts,  such  as  has  been 
used  with  some  degree  of  satisfaction  by  the  writer.  The  special  claim  of  this  grate 
reverts  to  its  freedom  from  blanks  or  dead  spots  and  the  equality  of  its  draft  dis- 
tribution. 

As  a  general  consideration,  however,  the  character  of  the  grate  must  depend 
upon  the  class  of  fuel  used,  the  size  of  the  voids  of  course  depending  upon  its  nature, 


44 


GAS   PRODUCERS 


a  memorandum  of  which  has  been  given  elsewhere.  Where  fuel  of  a  resinous  or 
clogging  nature  is  to  be  used,  especially  fuels  containing  high  quantities  of  sulphur 
and  bituminous  matter,  which  has  a  tendency  to  flux  or  run,  it  will  probably  be 


FIG.  17. — Shaking  Grates  Applied  to  Gas  Producer. 

found  expedient  to  use  the  grates  of  the  repose  type,  even  at  the  expense  of  wasted 
fuel. 

Down-Draft  Grates.     The  grates  used  in  the  apparatus  of  the  Loomis-Pettibone 
type    are   of   fire-brick   and   are   somewhat   difficult    of   cleaning   and    ash    removal. 


FIG.  18. — Water-cooled  Repose  Grates. 


There  is  no  particular  disadvantage  in  water-cooled  grates  (only  necessary  in 
down-draft),  where  the  gas  is  used  for  power  purposes,  if  a  fairly  heavy  ash  bed  is 
interposed  between  the  grates  and  the  combustion  area,  preventing  undue  heat 


PRODUCER   OPERATION 


45 


transference  between  same.  The  water  cooling  of  the  grates  does  not  rob  the  fire 
of  an  unreasonable  amount  of  heat,  and  serves  as  a  first  stage  of  condensing  or 
cooling  of  the  sensible  heat  of  the  outgoing  gases. 

Size  of  Bars.  With  regard  to  the  specifications  of  grates,  these  should  be 
invariably  designed  with  reference  to  the  fuel  to  be  used.  For  anthracite  coal  the 
bars  in  the  grate  should  be  of  the  following  diameter  approximately:  rice  ^-inch; 
pea  f-inch;  nut  ^-inch;  egg  f-inch. 

Where  a  mixed  fuel  is  used,  that  is  to  say  a  fuel  of  mixed  sizes,  the  size  of  the 
bars  should  be  in  correspondence  with  that  of  the  smaller  fuel  used.  Bituminous 
coal,  run  of  mine,  requires  bars  from  f  to  Jkinch;  slack  £-inch. 

For  a  clinker  anthracite  coal,  dumping  grates  should  be  invariably  used,  while 
with  a  non-clinkering  bituminous  coal  shaking  grates  are  usually  satisfactory.  For 


FIG.  19. — Water-cooled  Repose  Grates,  Area  Reduced  by  Blanks. 

non-clinkering  anthracite  or  bituminous,  ordinary  grate  bars  may  be  used,  but  for 
all  around  purposes  a  combination  of  shaking  and  dumping  grate  will  be  found  to 
give  the  best  results. 

Repose  Grates.  Repose  grates  are  designed  with  special  reference  to  ease  of 
stoking  and  cleaning,  distribution  of  circulation,  and  for  use  with  down-draft 
apparatus,  though  not  limited  to  that  type.  The  grate  consists  of  a  number  of 
triangular  bars  which  are  water  cooled  with  water  circulation  occurring  through 
a  header  upon  one  side  of  the  producer.  These  bars  are  so  introduced  as  to  create 
certain  angles  of  repose  of  the  ash  bed  within  their  voids,  the  effect  being  to  accel- 
erate and  distribute  the  flow  of  the  air  or  gases  through  the  total  area  at  equal 
pressure. 

Another  arrangement  shows  a  combination,  of  the  bars  for  blanking  certain 
portions  of  the  cross-section  of  the  producer,  where,  by  reason  of  adjacency  to  the 
tuyeres  or  otherwise,  there  may  have  been  an  undue  short-circuiting  of  the  gas  or 


46  GAS   PRODUCERS 

air,  and  it  is  by  retarding  this  tendency,  or  by  baffling  or  diverting,  to  disseminate 
the  flow  more  generally  throughout  the  cross-section,  diminishing,  channeling,  wire 
drawing,  or  localization  of  draft. 

Besides  the  mere  chemical  advantage  of  general  distribution  the  blanking  of 
the  grate  permits  the  drawing  away  of  the  hydrocarbon  products  of  the  distillation 
zone  from  any  combustion  vortex  and  a  consequent  reduction  of  secondary  com- 
bustion within  the  producer. 

These  grates  may  also  be  pivoted  and  used  as  rocking  and  dumping  grates, 
the  upper  and  lower  tiers  being  operated  seriatim.  In  no  instance,  however,  is  their 
fuel  efficiency  very  high.  Where  used  in  down-draft  apparatus  a  relatively  high 
ash  bed  should  be  carried,  both  to  prevent  waste  of  fuel  and  to  insulate  the  com- 
bustion zone  from  the  grates,  hence  diminishing  the  heat  transference  and  "  rob- 
bing "  of  the  jacket  water.  The  water  cooling  then  tends  merely  to  cool  and  con- 
dense the  effluent  gases,  instead  of  abstracting  useful  heat  from  the  fire  at  the 
expense  of  fuel.  Repose  grates  are  most  satisfactory,  and  their  fuel  loss  reduced 
to  a  minimum  in  the  use  of  coking  coal. 

Grates  for  Lignites.  Where  lignites  or  low-grade  fuels  are  used  it  is  sometimes 
necessary  to  insert  a  secondary  or  upper  grate  in  the  shaft  of  the  producer  for  the 
purpose  of  supporting  the  upper  section  of  the  fuel  charge  and  the  maintenance 
of  an  incandescent  or  dissociation  zone.  This  is  to  prevent  or  equalize  the  exces- 
sive rapidity  in  the  drop  of  the  charge  at  a  critical  point  of  temperature  or  stage 
of  combustion,  which  the  writer  will  term  the  point  of  "  ashification." 

This  critical  point  in  the  combustion  of  low-grade  fuels  occurs  by  reason  of 
the  distilling  out  of  the  high  moisture  and  volatile  content,  which  acts  as  a  binder 
between  the  carbon  and  the  diluent  elements  of  the  fuel. 

In  the  case  of  low-grade  fuels  this  distillation  of  the  binding  elements  (princi- 
pally moisture  and  hydrogen)  is  very  rapid,  and  results  in  the  sudden  "  fining  " 
or  precipitation  on  the  part  of  the  fuel,  the  high  ash  content  serving  to  choke  the 
draft,  and  through  its  insulating  properties  to  prevent  chemical  reaction  necessary 
for  gas  formation. 

A  condition  analogous  to  this  is  found  in  lime  burning,  where  the  paradox 
exists  that  the  softer  or  less  refractory  the  lime  stone  (CaCO-O  the  more  difficult  it 
is  to  burn.  This  is  by  reason  of  certain  mass  action;  that  is  to  say,  that  prior  to 
calcination  (reaction  to  CaO)  at  an  early  period  of  the  process,  and  at  a  relatively 
low  temperature,  the  stone  disintegrates  or  fines,  creating  a  precipitation  of  finely 
powdered,  closely  packed  limestone,  forming  a  dense  mass  almost  impenetrable 
to  the  passage  of  air  or  gases,  and  presenting  a  poor  heat  conductor  necessary  to 
the  final  calcination. 

The  interposition  of  the  second  grate  aforesaid  supports  the  fire  but  prevents 
packing  consequent  to  the  conditions  named.  Though  but  little  used  in  America 
they  have  had  long  and  successful  operation  abroad.  The  fact  that  a  10  per  cent 
ash  content  in  using  coal  is  at  present  the  American  limit  of  low-grade  fuel  utiliza- 
tion, while  the  German  practice  has  run  as  high  as  40  per  cent  moisture  and  20  per 
cent  ash,  is  an  attest  to  the  efficiency  of  the  arrangement.  In  Germany  the  Jahns- 
Ring  producer  has  been  successfully  run  upon  fuels  containing  only  20  per  cent  of 
combustible  matter. 


PRODUCER   OPERATION 


47 


FIG.  20.— Repose  Grates  for  Lignite  Fuel. 


48  GAS   PRODUCERS 

In  this  country  the  utilization  of  such  poor  fuels  has  not  yet  been  attempted, 
nor  should  the  writer  advise  its  attempt  in  any  type  of  shaft  producer.  The  use 
of  the  double  grate  herein  suggested  is  advisable  for  fuels  approximating  20  per  cent 
or  more  of  moisture,  or  in  those  fuels  where  the  "  ashification  "  is  extremely  rapid. 

The  auxiliary  or  upper  grate  is  best  made  of  heavy  fire-brick,  cored,  and  rein- 
forced with  iron  piping,  which  may  be  supported  in  various  manners — the  piping 
or  core  of  the  grate  being  water  cooled. 

The  iron  cores  are  for  strengthening  the  grate  and  making  it  more  solid  and 
durable,  while  this  water  is  cooling  a  precaution  against  over-heating.  The  fire- 
brick covering  is  essential  to  the  grate,  in  order  that  the  center  of  the  fuel  bed,  where 
it  reposes,  shall  be  robbed  of  the  minimum  heat. 

Burning  Out.  Franz  Walter,  of  the  Vienna  Gas  Works,  notes  that  the  fire  bars 
or  grate  bars  have  the  appearance  of  being  melted,  when  such  cannot  in  reality  be 
the  case,  as  the  temperature  maintained  at  this  location  in  the  furnace  is  below  the 
point  of  fusion,  nor  are  the  bars  sulphided. 

Mr.  Walter  attributes  the  result  to  the  slagging  of  the  iron  with  silica  and  ash 
content  of  the  fuel  in  the  presence  of  the  moist  and  heated  air.  The  slag  becomes 
more  and  more  basic,  finally  attaining  the  composition  of  2FeOSi02,  which  has 
the  power  of  dissolving  large  quantities  of  iron  oxide,  Fe203.  Consequently  bars 
may  be  found  with  absolutely  no  metallic  iron  in  them. 

These  changes  occur  of  course  only  in  high  temperatures,  and  to  prevent  this 
action  tubular  bars  or  air-cooled  bars  are  necessary,  or  at  least  interspersed  between 
solid  bars  in  the  proportion  of  two  tubular  bars  to  one  solid  one. 


CHAPTER  II 
CLEANING   THE  GAS 

General  Conditions. — In  considering  the  necessary  conditions  of  cleaning  gas, 
two  elements  must  be  thoroughly  understood;  first,  the  nature  of  the  impurities 
to  be  removed,  and  second,  the  conditions  under  which  these  impurities  are  removed. 

To  all  present  purposes  under  the  first  head,  the  impurities  in  gas  consist  of 
three  classes,  namely,  dry,  liquid,  and  semi-liquid.  Under  the  first  we  may  include 
lampblack,  metallic  dust,  and  small  portions  of  ash.  Under  the  second,  moisture, 
steam,  and  aqueous  vapor.  Under  the  third,  tar,  and  also  an  emulsion  containing 
all  or  several  of  the  foregoing  ingredients  in  various  proportions. 

The  condition,  under  which  gas  precipitates  its  impurities  are,  generally  speak- 
ing, as  follows: 

a.  Cooling.     This   condition   primarily  effects  a  change  of  volume,  a  change  of 
density,  a  change  of  vapor  tension,  and  a  consequent  dew  point. 

b.  Change  of  volume.     This  condition  of  precipitation  of  impurities  occurs  largely 
through  a  change  of  vapor  tension. 

c.  Change  of  pressure.     It  is  well  known  that  an  increase  of  pressure  tends  to 
compress  out  any  supersaturation  of  gases,  probably  due  to  the  change  of  volume, 
as  noted  in  b. 

d.  Impingement.     The  impingement  of  a  gas  upon  any  baffling  substance  tends 
to   remove   its   impurities,    probably   because   of  the   strong   capillary   and   cohesive 
attraction  of  these  impurities  themselves. 

e.  Centrifugal  action.     The  centrifugal  action  by  which  gas,  when  revolved  about 
any  axis,  tends  to  rid  itself  of  any  impurities,  is  easily  understood,  and  this  is  due 
of  course  to  the  greater  density  of  those  impurities. 

/.  Reversion  of  direction.  Any  gas  whose  direction  or  flow  is  reversed  or 
diverted  tends  to  deposit  its  saturation  of  impurities.  It  is  likely  that  this  phenom- 
enon, however,  is  caused  by  certain  centrifugal  action,  as  suggested  in  e. 

g.  Velocity.  Another  function  of  gas  is  to  deposit  its  saturation,  or  rather  super- 
saturation,  at  whatever  point  its  velocity  of  flow  may  be  caused  to  lessen. 

h.  Filtration.     Passing  through  screens  or  beds  of  porous  material. 

i.  Washing.  Efforts  are  being  made  by  a  number  of  manufacturers  of  apparatus 
to  purify  producer  gas  through  filtration,  the  line  upon  which  many  of  them  are 
working  being  to  bubble  the  gas  from  a  number  of  orifices  through  a  seal  or  lute  of 
oil  beneath  which  the  gas  has  been  submerged.  This  oil  is  periodically  filtered  and 
renewed.  The  system  is  said  to  be  fairly  efficacious  for  the  removal  of  dust  and 
lampblack. 

49 


50  GAS   PRODUCERS 

Bearing  these  functions  in  mind,  the  purification  of  gas  should  be  done  about 
as  follows: 

It  may  be  sufficient,  where  gas  is  used  merely  for  furnace  or  boiler  firing,  to 
remove  the  dust  or  dry  impurities,  such  impurity,  especially  in  the  instance  of  blast 
furnace  gas,  tending  to  clog  the  mains,  choke  up  flues  and  linings,  and  create  further 
objectionable  difficulties. 

It  should  be  remembered,  however,  that  a  reduction  in  the  sensible  tempera- 
ture of  a  gas  means  a  resultant  deduction  or  subtraction  from  the  resultant  flame 
temperature  of  combustion.  This  purification  must  therefore  be  accomplished  with 
the  least  possible  loss  of  heat  and  the  baffle  separator  involving  the  principle  of 
impingement  and  reversion  of  direction  is  to  be  recommended. 

Where  gas  is  to  be  used  for  power,  however,  a  complete  purification  is  necessary, 
for  it  is  the  history  of  gas  power  work  that  almost  without  exception  failure  in 
successful  operation  is  to  be  attributed  to  impure  and  unfiltered  gas. 

Moreover,  it  is  necessary  in  power  work  to  condense  the  heat  value  of  a  gas  into 
its  least  possible  compass  (under  ordinary  conditions  say  at  86°  F.)  and  to  this  end 
a  cooling  process  must  be  effected. 

The  cooling  process  creates  a  dew  point  or  precipitaion  of  all  liquid  or  semi- 
liquid  contents,  for  it  is  a  known  fact  1  cu.ft.  of  space  at  70°  F.  cannot  contain 
more  than  8  gr.  of  water  vapor,  or  1  cu.ft.  at  50°  F.  more  than  4  gr.,  nor  can 
1  cu.ft.  at  32°  F.  contain  more  than  2  gr. 

The  more  quickly  a  gas  is  cooled  after  manufacture  the  sooner  its  volume  is 
reduced  and  the  more  rapidly  it  may  be  handled  in  subsequent  stages  of  the  puri- 
fication; that  is  to  say,  assuming  one  thousand  feet  of  gas  to  leave  the  producer 
at  560°  F.,  when  this  gas  is  reduced  to  60°  F.  the  volume  would  be  approximately 
only  500  cu.ft.,  which  from  the  standpoint  of  both  pumping  and  cleaning  can  be 
much  more  economically  and  efficiently  handled.  We  will  therefore  see  that  the 
wet  scrubber  for  power  work  should  be  logically  the  first  in  the  series. 

The  tar  and  the  emulsions  which  have  been  referred  to  are,  however,  too  tena- 
cious to  be  removed  by  merely  cooling  and  washing,  the  tendency  of  the  gas  more- 
over being  to  pass  through  the  wet  scrubber,  even  one  of  the  film  or  mist  type,  more 
or  less  in  the  form  of  rivers  or  chimneys,  the  intermixture  not  being  particularly 
intimate. 

To  overcome  this  and  obtain  a  closer  mixture,  and  for  more  thorough  scrub- 
bing, a  power  scrubber  is  next  intervened,  its  functions  being  multiple,  tending  to 
(a)  coagulate  the  tar  globules  (oils  and  moisture),  (6)  to  break  up  intermixing, 
and  finally  divide  gas  and  water,  thoroughly  cleansing  and  cooling  it,  and  (c)  to  rid 
the  gas  of  its  impurities  through  centrifugal  action.  Where  very  severe  scrubbing  is 
required  it  is  sometimes  necessary  to  connect  two  or  more  of  these  rotary  scrubbers 
in  series. 

Following  what  is  usually  customary,  though  not  always  necessary,  to  have 
dry  scrubbers  where  some  filtering  material  tends,  through  the  above  principle  of 
baffling  and  impingement,  to  remove  any  impurity  which  has  escaped  the  foregoing 
process  and  to  take  out  any  moisture  which  may  have  been  carried  over  in  suspense. 

Following  these  last  in  series  and  usually  made  adjacent  to  the  engine  is  the 
receiving  tank,  which  performs  the  following  functions:  First,  to  have  a  large  supply 


CLEANING   THE    GAS 


51 


of  gas  made  adjacent  to  the  engine  and  by  its  elastic  volume  to  act  as  a  cushion 
for  the  cutoffs  of  the  valves,  thereby  preventing  any  "  hammer,"  and  also  to  act  as 
a  moisture  separator,  freeing  the  gas  from  any  moisture  carried  over  from  the  purify- 
ing system  or  (a  more  frequent  evil,  especially  after  stand-bys)  condensation  in  the 
pipes. 

This  receiving  tank  may  or  may  not  contain  baffle  plates.  In  the  latter  case 
it  depends  upon  the  actions  (6)  and  (</),  that  is  to  say,  change  of  volume  and  of 
velocity  of  flow,  as  previously  described. 

Efficiency  is  materially  increased  by  increasing  the  size  of  scrubbers  and  con- 
nections. For  two  reasons:  First:  with  increased  volume  gas  distends  and  presents 
more  surface  for  cooling  and  scrubbing  action;  second,  the  velocity  of  passage 


SECTION  fUONT   ELEVATION 

FIG.  21. — Dry  Scrubber  used  by  the  Lacka wanna  Steel  Co. 

per  unit  of  gas  is  decreased,  with  the  result  that  the  mechanical  ingredients  tend  to 
settle  by  gravity. 

Connections  should  be  as  elastic  as  possible,  permitting  as  nearly  as  possible 
the  temporary  by-passing  of  any  unit,  as  it  is  often  possible  by  temporarily  over- 
loading the  remaining  unit,  to  by-pass  and  repair  an  obstruction  and  thereby  pre- 
vent a  total  shut  down.  With  the  exception  of  the  engine,  practically  all  of  the 
other  apparatus  may  be  momentarily  overloaded  to  a  considerable  extent. 

Dry  Scrubbers. — Dry  scrubbers  and  small  apparatus  should  have  hopper- 
shaped  dumping  valves  to  facilitate  cleaning  and  removal  of  stoppages.  These 
valves  are  dust  sealed  with  automatic  dust  doors,  held  in  place  with  levers  and 
counter  weights,  serving  as  blow-off  or  safety  valves  in  case  of  puffs  or  explosions. 

The  Lackawanna  Steel  Company  purifies  its  blast  gas  down  to  0.663  and  to 
0.524  grains  of  dust  per  3500  cu.ft. 


52 


GAS   PRODUCERS 


CLEANING  THE   GAS  53 

The  dry  scrubber  is  preferably  designed  with  two  compartments,  so  arranged 
that  the  gas  may  be  turned  in  either  part  of  the  scrubber  at  will.  The  dry  scrubber 
should  be  equal  in  area  to  the  net  in  side  diameter  of  the  generator,  according  to 
the  best  English  practice. 

Oil  soaked  excelsior  is  extensively  used  as  a  scrubbing  material. 

Concerning  filtering  material  to  be  used  in  scrubbers,  generally  speaking,  broken 
coke  in  a  wet  scrubber  is  most  serviceable,  as  after  it  has  become  fouled  it  may  be 
burned.  Sawdust  or  small  shavings  in  the  dry  scrubber  or  coke-breeze,  the  latter 
to  a  depth  of  30  in.,  may  be  used  if  the  gas  is  perfectly  dry  upon  reaching  the  dry 
purifier;  otherwise  it  has  a  tendency  to  pack. 

Mineral  wool  is  one  of  the  best  substances  for  dry  scrubbers,  and  very  oily  waste 
can  likewise  be  used  to  advantage. 

The  most  satisfactory  filling  for  dry  scrubbers  would  seem  to  be  a  mixture  of 
sawdust  and  planer  chips,  say  half-and-half.  This  combination  possesses  the  scour- 
ing advantages  of  the  sawdust,  while  packing  is  prevented  by  the  intermixture  of 
the  shavings.  The  sawdust  also  has  a  tendency  to  fill  in  the  voids  otherwise  left 
by  the  shavings. 

Removing  Dust  from  Furnace  Gas. — The  illustrated  apparatus  showing  arrange- 
ment of  gas  cleaning  apparatus  covers  a  layout  for  a  hundred  ton  blast  furnace,  as 
made  by  the  Buffalo  Forge  Co.,  who  have  had  perhaps  the  largest  experience  in 
the  United  States  in  the  construction  of  such  plants  for  the  steel  manufacturing 
industry.  The  equipment  is  capable  of  handling  10,000  cu.ft.  of  gas  per  minute. 
This  capacity,  is  measured  at  the  discharge  of  the  rotary  scrubbers,  where  the  gas 
may  be  at  a  temperature  of  about  125°  F. 

Upon  leaving  the  blast  furnace  the  gas  would  pass  through  a  42-in.  duct,  which 
should  be  constructed  of  ^-in.  black  steel,  lined  with  fire-brick,  to  the  cooling  spray 
chamber.  This  is  constructed  of  the  same  material,  and  equipped  with  three  sets 
of  spray  nozzles,  which  injects  a  fine  spray  of  water  in  a  direction  opposite  to  that 
of  the  flow  of  the  gas.  These  nozzles  require  about  72  gallons  of  water  per  minute 
at  a  pressure  of  25  Ibs. 

After  passing  through  this  chamber  the  gas  enters  the  dry-dust  separator  as 
shown,  where  a  considerable  portion  of  the  dust  is  deposited,  and  drawn  out  through 
a  gate  at  the  lower  end  of  the  separator.  After  leaving  the  separator,  the  gas 
passes  through  the  vertical  static  scrubber  and  washer.  This  is  equipped  with 
four  sets  of  nozzles,  discharging  the  water  in  a  direction  opposite  to  the  flow  of 
gas.  This  requires  260  gallons  of  water  per  minute  at  a  pressure  of  25  Ibs.  per 
sq.in.  This  scrubber  is  arranged  with  a  water  seal  at  the  bottom,  so  that  the  dust 
extracted  from  the  gas  would  pass  out  into  the  settling  tank  below. 

Upon  leaving  this  washer  the  gas  passes  into  one  of  the  rotary  scrubbers  and 
blowers.  These  are  shown  in  duplicate,  only  one  of  which  is  operated  at  a  time, 
each  having  a  capacity  of  10,000  feet  of  gas  per  minute.  In  addition  to  this  being 
a  rotary  scrubber,  it  also  acts  as  an  exhaust  fan,  giving  a  suction  corresponding  to 
a  4-in.  water  column  at  the  inlet.  This  requires  120  gallons  of  water  per 
minute. 

The  gas,  upon  leaving  this  rotary  scrubber,  is  ready  for  the  gas  engine,  and  does 
not  contain  more  than  0.02  grain  of  dust  per  cubic  foot.  This  is  sufficiently  clean 


54  GAS   PRODUCERS 

for  gas  engines.  As  a  matter  of  fact  it  has  been  found  by  test  that  the  dust  will 
not  be  more  than  0.01  grain  per  cubic  foot. 

These  scrubbers  are  really  a  three-stage  exhauster.  The  gas  entering  the  first 
stage  is  thrown  against  the  periphery  of  the  shell,  where  it  comes  in  contact  with 
a  large  number  of  sprays.  There  is  also  a  number  of  sprays  at  the  inlet.  The  gas 
being  thrown  against  the  peripheral  shell  at  a  high  velocity  the  dust  comes  in 
contact  with  a  sheet  of  water  and  is  carried  away  through  a  water  seal,  while  the 
gas  passes  over  into  the  second  stage  which  is  in  the  same  shell  as  the  first  stage, 
and  here  the  gas  passes  inwardly  to  the  third  stage.  These  two  wheels  in  the  first 
and  second  stage  are  of  approximately  the  same  diameter,  and  counteract  each 
other. 

The  gas  entering  the  thira  stage  has  almost  the  same  pressure  as  when  it  entered 
the  first.  In  the  third  stage  there  are  also  a  number  of  sprays  giving  a  sheet  of 
water  around  the  peripheral  shell,  and  the  dust  that  happened  to  escape  the  water 
in  the  first  stage  is  extracted  in  the  third.  Here  the  gas  is  discharged  at  the  per- 
iphery, as  in  ordinary  fans,  and  against  a  pressure  determined  by  the  speed  and 
diameter  of  the  blast  wheel.  These  rotary  scrubbers  require  a  speed  of  565  r.p.m. 
and  should  be  directly  connected  to  50  h.p.  motors. 

The  cleaning  of  furnace  gas  is  becoming  of  great  importance  in  the  economical 
manufacture  of  iron  and  steel.  It  is  necessary  to  clean  furnace  gas  of  practically 
all  the  solid  matter,  consisting  of  the  furnace  ingredients,  in  order  to  use  the  gas 
successfully  in  internal  combustion  engines,  and  is  also  found  desirable  and  pro- 
ductive of  economy  to  partially  clean  the  gas  used  in  the  stoves  and  blast  furnaces. 
The  dust  and  dirt  from  uncleaned  gas  amounting  to  12  to  30  gms.  per  cubic  meter 
(5  to  13  grains  per  cubic  foot)  is  gradually  deposited  on  the  heating  surface  of 
the  stoves,  and  acting  as  an  insulator  prevents  the  rapid  absorption  of  the  heat 
by  the  brick  work,  and  also  makes  the  frequent  cleaning  of  the  stoves  imperative. 
Higher  temperatures  are  obtained  when  clean  gas  is  used,  and  it  has  been  found  that 
the  saving  in  coke  consumption  under  these  conditions  amounts  in  a  100-ton  fur- 
nace to  about  $9000  per  year;  this  of  course  depending  entirely  upon  the  analysis 
of  both  the  ore  and  fuel  used. 

While  the  large  particles  of  ore,  limestone,  and  coke  in  the  gas  are  precipitated 
by  gravity  into  the  pockets  of  the  flues,  the  fine  arid  impalpable  dust  will  remain 
suspended  in  the  gas-like  smoke  in  the  atmosphere,  and  can  only  be  removed  by 
washing,  filtering,  and  the  various  processes  described.  When  furnace  gas  is  used 
for  fuel  in  the  cylinder  of  an  engine  a  very  small  amount  of  dust  is  prohibitive,  as 
it,  naturally  gritty,  will  unite  with  the  oil  of  lubrication,  forming  a  pasty  mass 
which  produces  an  abrasive  effect  only  excelled  by  oil  and  emery.  As  75  per  cent 
of  the  dust  is  metallic  oxide,  it,  when  subjected  to  a  temperature  of  3000°  F.,  the 
heat  of  inflammation,  will  be  precipitated  as  iron  or  steel.  The  impalpable  dust, 
so  light  that  it  will  be  carried  along  with  the  current  of  gases,  does  not  affect  the 
furnace  stoves  so  rapidly,  and  the  gas  used  in  these  regenerators  need  not  of  course 
be  as  clean  as  the  gas  used  in  the  engine  cylinders.  In  fact,  if  the  gas  used  in  the 
furnace  stoves  has  less  than  0.5  gm.  of  dust  per  cubic  meter  (0.22  grains  per  cubic 
foot)  the  heating  effect  of  the  gas  is  too  rapid  and  intense  and  the  melting  of  the 
brick  lining  is  liable  to  take  place.  On  the  other  hand,  gas  used  in  internal  com- 


CLEANING  THE   GAS  55 

bustion  engines  should  not  have  over  0.02  gm.  of  dust  per  cubic  meter  (0.009 
grain  per  cubic  foot)  or  the  wearing  of  the  engine  cylinder  will  be  excessive.  When 
used  under  boilers  for  making  steam,  the  freer  the  gas  from  solid  matter  the  better. 
The  efficiency  of  gas-fired  boilers  depends  as  much  on  the  side  of  the  tube  next  to 
the  fire  being  clean  as  the  side  surrounded  by  the  water. 

The  maximum  limit  of  cleaning  blast  gas,  however,  should  not  exceed,  even 
for  boiler  firing,  a  purity  of  extraction  with  a  less  limit  of  residual  exceeding 
0.2  grain  of  dust  per  cubic  foot.  The  dust  in  blast  furnace  work  varies  largely,  and 
depends  of  course  on  the  quality  of  coal  and  the  analysis  of  the  ore  being  reduced. 

Nearly  all  the  difficulties  experienced  in  America  with  blast  gas  for  power  pur- 
poses have  been  derived  from  an  improper  or  insufficient  cleaning.  The  dust  con- 
tained in  blast  furnace  gas  largely  exceeds  that  derived  from  producer  gas  manu- 
facture, one  reason  being  the  high  velocity  of  the  blast  and  the  high  rate  of  gasification 
of  blast  furnaces,  ranging  all  the  way  from  50  to  100  Ibs.  of  fuel  per  square  foot  of 
cross-section. 

Moreover,  the  dust  of  blast  furnaces  varies  greatly  from  that  of  producer  gas 
in  analysis,  more  than  three-fourths  of  its  content  being  metallic  ingredients  derived 
from  the  ore. 

By  reason  of  its  leanness  or  low  calorific  value  it  is  necessary  to  condense  blast 
furnace  gas  to  its  smallest  possible  compass,  which  entails  complete  condensation. 
This  usually  involves  a  range  of  temperature  in  its  reduction  of  volume  of  from  150 
to  25  or  30°  C. 

Constant  accurate  determination  is  an  essential  accessory  for  every  steel  or 
producer  plant:  in  the  former,  for  both  power  and  hot  stove  work,  and  for  the  latter 
for  all  power  purposes.  Proper  apparatus  in  such  investigation  and  record  must 
necessarily  be  installed. 

Dust  Determination. — Such  an  instrument  must  be  simple,  its  accuracy  unques- 
tionable, and  its  design  such  that  the  determinations  may  be  made  hourly  or  as 
often  as  desired.  The  ordinary  method  of  determining  the  dust  in  the  air  or  gas 
is  to  make  a  filter  of  a  glass  tube  filled  with  absorbent  cotton  through  which  the 
air  to  be  filtered  flows.  The  ga,s  is  measured  through  a  test  meter  and  the  cotton 
is  weighed  before  and  after.  This  method  might  give  accurate  results  if  the  cotton 
always  has  the  same  density  throughout  the  tube  and  were  not  hydroscopic.  The 
cotton  may  be  packed  in  so  loosely  that  some  of  the  dust  will  work  through,  and 
unless  the  cotton  is  carefully  dried  over  calcium  chloride  and  weighed  several  times, 
a  long  and  tedious  process,  errors  will  naturally  arise.  Experiments  have  shown 
that  as  two  cotton-filled  tubes  are  used  in  tandem,  the  second  will  increase  in 
weight,  showing  that  some  of  the  impalpable  dust  is  not  retained  by  the  first  tube. 
The  filtering  medium  for  the  apparatus  herein  described  is  simply  a  diaphragm 
of  white  filter  paper  through  which  the  gas  percolates,  but  on  account  of  the  minute 
interstices  of  the  medium  every  atom  of  dust  or  dirt  remains  behind.  The  side 
through  which  the  gas  enters  becomes  the  color  of  dust,  while  the  other  side  remains 
uncolored.  When  twro  filters  are  used  in  tandem,  the  second  does  not  increase  in 
weight,  showing  that  no  dust  permeates  such  a  filtering  medium.  The  velocity 
of  the  gas  through  the  filters  and  a  test  meter  which  has  but  a  one-quarter  inch 
pipe,  is  not  rapid,  and  if  the  instrument  is  erected  some  distance  from  the  main 


56  GAS   PRODUCERS 

supply  pipe,  the  deposition  of  dust  on  the  way  to  filter  will  cause  an  appreciable 
error.  In  the  apparatus  described,  the  three-quarter  inch  pipe  passing  across  the 
top  of  the  filter  holder  allows  a  considerable  quantity  of  gas,  which  keeps  the  dust 
stirred  up  to  pass  the  opening,  to  filter  at  a  fair  velocity  so  that  the  amount  filtered 
out  must  be  indicative  of  the  total  dust  in  gas. 

By  keeping  continuous  records  of  the  dust  in  the  gas  before  and  after  clean- 
ing, the  efficiency  of  the  cleaners  can  be  maintained.  A  check  on  the  operation 
of  the  furnace  is  possible,  and  the  minimum  wear  of  the  engine  cylinders  is  insured. 


FIG.  23. — Sargent  Dust  Determinator,  Compact  form. 

A  record  of  the  condition  of  the  furnace  gas  is  essential  in  its  commercial  use.  The 
illustration  shows  the  complete  self-contained  determinator,  which  consists  of  a  port- 
able case  containing  an  accurate  test  meter,  two  filter  holders  in  section,  complete 
cross-connection  three-quarter  inch  brass  piping,  so  that  gas  to  be  tested  may  flow- 
over  the  mouth  of  either  filter,  and  hose  connections  allowing  the  gas  passing  through 
the  filter  paper  to  be  accurately  measured  through  the  test  meter.  When  the  desired 
percentage  of  moisture  in  the  gas  is  obtained,  the  gas  is  passed  through  a  cooling 
coil,  where  most  of  the  moisture  is  condensed  and  precipitated  in  a  collecting  bottle. 
After  passing  the  cooling  coil  the  gas  is  passed  through  three  or  four  bottles  of 
calcium  chloride,  removing  effectually  any  further  moisture  in  the  gas  before  it  is 


CLEANING   THE   GAS  57 

metered  or  its  calorific  value  is  determined.  When  the  determinations  are  merely 
for  finding  the  percentage  of  dust,  the  cleaned  gas,  after  leaving  the  meter,  is  mingled 
with  the  main  supply  and  burned  or  wasted  to  the  atmosphere.  The  cleaned  dried 
gas  may  be  passed  through  an  automatic  calorimeter,  by  which  the  B.T.U.  are 
determined  as  well  as  the  hydrogen  in  the  gas.  A  complete  record  of  the  dust  and 
calorific  value  is  an  indication  of  the  internal  furnace  conditions  described  in  the 
economical  manufacture  of  steel.  By  using  two  filter  holders  continuous  determi- 
nation can  be  made.  By  the  proper  manipulation  of  the  valves  gas  can  be  passed 
through  either  filter,  while  the  dust  collected  in  the  other  per  cubic  foot  of  gas  burned 
is  being  ascertained.  On  account  of  the  moisture  in  the  gas  softening  up  the  filter 
paper,  a  wire  gauze  is  inserted  under  the  filtering  medium  which  prevents  the  weight 


FIG.  24. — Sargent  Determinator,  complete. 

of  the  dust  from  tearing  it.  As  the  deposited  dust  and  filter  paper  remain  more 
porous  if  kept  warm  and  dry,  an  incandescent  lamp  or  candle  is  burned  under  the 
filter  holder  in  use.  The  inlet  and  outlet  pipe  for  gas  passes  through  the  case,  which 
is  provided  with  a  door  and  lock  and  may  be  left  running  for  twenty-four  hours  if 
desired,  though  hourly  readings  may  be  obtained  if  the  variations  of  the  dust  under 
different  conditions  are  desired.  The  proportion  of  gas  wasting  and  going  through 
the  meter  is  adjustable,  and  can  be  regulated  to  suit  the  conditions  and  location 
of  the  apparatus  relative  to  the  flue  from  which  the  sample  is  taken.  If  the  burn- 
ing or  wasting  of  the  gas  flowing  by  the  filter  mouth  is  not  desirable  it  may  be 
piped  back  into  the  gas  flue  in  such  a  wray  as  to  maintain  a  circulation  through  the 
shunt. 

The  operation  of  the  determinate*  is  as  follows: 

Locate  the  instrument  as  close  to  the  flue  containing  the  gas  as  practicable. 
Run  a  three-quarter  inch  pipe  from  flue  to  inlet  pipe  at  the  case.  Run  the  waste 
pipe  where  desired.  Level  and  fill  test  meter  w-ith  water  until  it  rises  to  the  level 
indicated  in  the  glass  by  the  pointer.  Place  filter  paper  in  holder  and  tighten  thumb 


58  GAS    PRODUCERS 

screws.  (This  may  be  done  in  the  laboratory  where  filter  paper  is  weighed  if  desired, 
and  holder  can  be  connected  up  by  union.)  Note  the  reading  of  gas  meter,  the  date 
and  hour;  write  same  on  the  filter  holder  being  used.  After  a  certain  time,  depend- 
ing on  the  amount  of  dust  in  the  gas,  the  meter  is  read  and  the  gas  by-passed 
through  the  other  filter  which  had  been  previously  prepared.  Remove  the  filter 
holder  and  determine  the  amount  of  dust  collected  as  follows:  The  filter  paper 
having  previously  been  dried  and  weighed  should  be  carefully  dried  again  by 
subjecting  it  and  the  dust  attached  to  the  same  temperature,  not  less  than  212°  F. 
This  will  drive  off  the  moisture,  and  the  difference  between  the  weight  of  the  clean 
paper  and  the  dust-covered  paper  will  give  the  new  amount  of  dust  which,  divided 
by  the  cubic  feet  of  gas,  will  give  the  grains  or  grams  per  cubic  foot. 

To  get  the  percentage  of  moisture,  weigh  the  water  precipitated  in  the  inverted 
flask  below  condenser,  and  by  weighing  each  flask  of  calcium  chloride  (the  weight 
of  each  having  been  noted  before  test  began),  the  percentage  of  moisture  is  readily 
obtained.  In  order  to  be  sure  that  all  moisture  has  been  extracted,  the  last  flask 
through  which  the  gas  passes  should  not  increase  in  weight. 


FIG.  25. — Test  for  Dust  and  Moisture. 

A  pressure  gauge  and  thermometer  at  the  meter  will  allow  of  a  reduction  of 
the  meter  reading  to  standard,  should  this  be  desired  for  comparison.  As  fifteen 
to  twenty-five  per  cent  of  the  dust  in  furnace  gas  is  coke,  it  is  not  advisable  to 
determine  the  total  dust  by  incineration,  though  this  method  is  used  where  the 
solid  matter  collected  contains  no  combustible. 

When  air  or  gas  at  or  below  atmospheric  pressure  are  analyzed  for  foreign  mat- 
ter, a  water  ejector  is  used  to  draw  the  air  through  filter  and  meter.  If  the  dust  or 
tar  is  desired,  as  well  as  the  calorific  value  of  the  gas,  the  pressure  of  which  is  below 
atmospheric,  our  ejector  and  separator  which  draws  gas  through  filters  and  forces 
it  through  meter  into  chlorimeter,  is  used.  Separate  dust  determination  is  made 
by  precipitating  tar  and  by  cooling  gas  before  entering  filter. 

For  making  tar  determination  place  a  piece  of  absorbent  cotton  above  the 
filter  paper  in  the  filter  holder,  running  the  same  as  in  the  determination  of  dust. 
Separate  moisture  is  determined  by  connecting  calcium  chloride  flasks  direct  to 
the  gas  supply.  The  above  dust  determinator  is  manufactured  by  the  Sargent 
Steam  Meter  Co.,  of  Chicago. 


CLEANING  THE   GAS  59 

The  accompanying  illustration  is  a  rough  sketch  of  an  apparatus  which  is  used 
to  some  extent  among  the  steel  plants  for  the  removal  of  dust  and  chemical  impuri- 
ties in  the  blast  furnace.  This  instrument  is  made  of  brass  and  aluminum.  It 
consists  of  a  receiver  containing  a  perforated  metal  shelf  for  the  support  of  the  filter 
paper,  which  is  placed  thereon,  and  which  serves  to  collect  tar  and  dust.  The  stem 
of  the  apparatus  contains  calcium  chloride,  from  whence  the  moisture  content  is 
determined.  It  is  possible  to  make  a  direct  determination  of  the  supersaturation 
in  gas  by  condensing  it  directly  by  passing  through  a  water-jacketed  worm. 

Influence  of  Dust. — In  a  letter  under  date  of  July  3,  1908,  F.  E.  Junge,  of 
Gorlitz,  Germany,  writes  as  follows: 

"  Dust  is  an  inert  constituent  in  the  gas  and  acts  similar  as  ash  does  in  coal, 
when  the  latter  is  burned,  absorbing  heat  and  reducing  thereby  the  maximum 
obtainable  temperature  of  combustion.  It  also  has  a  reducing  influence  on  the 
rapidity  of  flame  propagation,  since  by  laboratory  investigations  in  experimental 
glass  tubes  wre  have  satisfied  ourselves  that  the  speed  of  flame  travel,  and  the  amount 
of  heat  developed  per  time  unit  grows  smaller  the  more  dust  is  added  to  the  gas, 
the  extreme  result  being,  of  course,  an  extinguishing  of  the  flame.  Therefore,  if 
dust  is  present,  less  of  the  combustible  of  the  gas  is  burned  in  the  furnace,  heat 
developed  being  postponed  and  valuable  properties  lost  to  the  atmosphere.  We 
cannot  get  around  the  fact  that,  in  numerous  instances,  the  coal  bill  has  been 
decreased  after  a  cleaning  plant  was  added  to  the  equipment,  and  we  cannot  but 
adjust  our  theories  to  the  achievements  of  practice." 

The  writer  believes,  except  in  exceptional  cases  of  blast  furnace  gas,  where 
the  content  of  entrained  metallic  oxides  and  dust  is  very  high,  that  no  gas  should 
be  washed  for  furnace  or  firing  purposes.  With  gases  of  this  kind,  a  large  quantity 
of  their  impurities  may  be  removed  by  dry  cleaning,  which  may  take  the  form  of 
almost  any  baffling  separator  which  removes  the  dust  and  dirt  through  impinge- 
ment, change  of  volume,  or  change  of  direction,  or  by  the  brushing  or  scrubbing 
effect  of  its  plates  or  contents. 

If  water  is  used,  it  is  the  belief  of  the  \vriter  that  the  loss  of  sensible  heat  (in 
itself  a  tremendous  disadvantage),  and  a  consequent  reduction  of  flame  tempera- 
ture, more  than  offsets  any  loss  that  may  accrue  through  the  absorption  of  heat 
by  the  dust,  or  by  the  clogging  and  insulating  effect  within  the  furnace. 

Except  under  exceptional  circumstances,  the  dry  cleaning  of  gas  will  be  found 
sufficient,  and  although  Mr.  Junge  speaks  of  the  extinguishing  of  the  flame  as  due 
to  dust  in  extreme  cases,  these  extreme  results  are  rarely  reached  in  practice,  or 
even  approximated.  In  fact,  so  great  a  portion  of  the  impurities  may  be  removed 
by  dry  scrubbing  that  the  remaining  entrainment  is  inconsiderable  under  working 
conditions  and  economics. 

Centrifugal  Rotary  Separators. — To  remove  substances  heavier  than  the 
gas,  such  as  water  and  dust,  centrifugal  force  has  been  utilized. 

Thiesen  Centrifugal  Gas  Washer. — The  Thiesen  centrifugal  gas  washer  consists 
of  a  drum  having  peripheral  vanes  whereby  the  gas  is  rotated  in  presence  of  a 
water  spray.  The  circulation  being  superinduced  by  a  fan  at  the  end  of  the 
washer. 

This  washer  claims  an  efficiency  of  24  to   1%  of  the  power   obtained   by   the 


60 


GAS   PRODUCERS 


total  gas  purified,  the  consumption  of  water  being  from  five  to  ten  gallons  per  1000 
feet. 


FIG.  26. — Thiesen  Centrifugal  Gas  Washer. 

Saaler  Washer. — The  Saaler  washer  is  one  of  the  centrifugal  type,  similar  in 
construction  and  operation  to  the  Thiesen  washer.  It  consists  of  a  drum  with  axial 
vanes  set  at  irregular  angles  to  the  plane  of  the  axis.  The  drum  is  connected  with 


FIG.  27. — Sections  of  Saaler  Gas  Washer  and  Vanes  on  Surface 
of  Drum. 


a  centrifugal  fan  of  the  paddle-wheel  type.  The  principle  of  the  washer  is  the 
emulsification  of  the  impurities  through  churning  and  intermingling  of  the  gas  and 
water,  and  the  expulsion  of  the  emulsion  through  centrifugal  force.  The  washer 


CLEANING   THE   GAS  61 

it  is  claimed  refines  the  gas  to  an  impurity  content  of  0.015   grain    of   matter  per 
cubic  foot. 

The  inclined  paddles  churn  the  water  to  the  left-hand  end,  and  the  gas  pressure 
and  fan  (Section  X-Y)  suction  forces  the  gas  the  contrary  direction.  The  paddles 
are  irregularly  arranged,  as  shown  in  the  view  of  the  drum. 

Latta  Heavy-duty  Separator. — The  gas  washer  herewith  shown  consists  of 
three  cylinders,  the  first  and  second  revolving  (preferably  in  opposite  directions), 
and  the  third  being  fixed  within  the  second. 

The  gas  entering  the  washer  at  A,  together  with  a  spray  of  water,  or  water 
mist,  is  drawn  through  the  cylinder  B,  which  is  perforated,  and  the  gas  and  water 
are  thereby  finely  divided  and  atomized. 

Through  the  space  C  and  the  cylinder  E  the  water  and  gas  mixture  is  drawn, 
being  forced  against  and  slightly  repelled  by  the  centrifugal  motion  of  the  vanes 
D,  which  are  perforated  in  order  to  produce  a  filtering  effect. 

The  gas  is  further  induced  through  the  cylinder  F,  where  a  further  quantity  of 
water  mist  is  added  through  the  shaft,  and  from  whence  the  gas  is  drawn  out  by 
the  peripheral  fan  (of  the  Sirocco  type)  G,  and  expelled  through  the  outlet  H. 

The  washer  depends  for  its  -efficiency  principally  upon  two  features:  First, 
the  emulsifying  of  the  impurities  through  the  very  close  intermixture  of  the  water 
and  impurities.  A  flushing  of  said  impurities  and  thorough  washing  of  the  gas, 
depending  upon  centrifugal  force,  upon  filtration  of  the  various  sieves,  vanes,  and 
cylinders,  and  upon  the  opposition  of  forces.  The  centrifugal  force  of  the  cylinders 
B,  E,  and  F,  and  the  vanes  D,  tend  to  throw  out  the  heavier  impurities  and  act  in 
an  opposite  direction  to  the  fan-blower  G,  which  forces  being  opposed  tend  to  wire- 
draw the  gas  away  from  its  impurities. 

Of  course  there  is  the  usual  cleansing  effect  due  to  dew  point,  supersaturation, 
and  the  absorption  of  impurities  due  to  the  fineness  of  division  and  the  intimacy 
of  the  intermixture  obtained. 

It  will  be  noticed  that  cylinder  E  and  the  vanes  D  in  sequence  are  suspended 
from  cylinder  B,  the  cylinder  F  to  which  the  blower  G  is  attached  running  free 
and  independent.  This  permits  the  regulation  of  blower  speed  and  consequent 
blower  pressure  through  the  variation  of  the  speed  of  F  and  G,  allowing  elasticity 
of  regulation  in  operation.  It  also  creates  a  compensation  through  additional  speed 
for  the  faster  rim  travel  of  the  cylinders  B  and  E  and  the  vanes  D,  through  a  greater 
length  of  radius. 

It  also  makes  a  slower  speed  necessary  upon  the  part  of  the  heavier  moving 
parts,  and  also  of  the  main  shaft  and  bearing,  reducing  the  general  travel  both  in 
part  and  in  total. 

Another  form,  a  light  service  tar  extractor,  is  based  upon  the  principles  of  the 
Latta  heavy-duty  gas  washer.  In  addition  to  filtration,  impingement,  change  of 
pressure  and  volume,  cooling  and  scrubbing,  the  unpurified  gas  upon  entry  is  brought 
into  contact  with  a  finely  divided  water  spray,  and  by  great  thoroughness  of 
agitation  the  impurities  are  emulsified  or  thrown  into  solution  by  contact  with  the 
water  and  moisture.  The  principal  feature  of  the  process  then  takes  place,  namely, 
an  "  intensified  stratification."  The  heavier  or  more  impure  matter  being  more 
amenable  to  centrifugal  action,  are  thrown  to  the  periphery  of  the  revolving  sepa- 


62 


GAS ' PRODUCERS 


-4?a_ 


03 

O) 

w 

03 

-t-a 

3 


-N 


CLEANING  THE  GAS 


C3 


rator,  while  the  lighter  or  purified  gases  forming  the  inner  complement  are  with- 
drawn through  the  suction  action  of  the  exhauster,  there  being  thus  two  forces  at 
work  on  the  impure  gas,  the  one  tending  to  divert  the  heavier  portions  outward, 
while  the  suction  draws  away  the  lighter  portion  thus  freed  from  the  center,  draw- 
ing more  gas  in  to  be  separate  in  turn  by  continuous  operation. 

Fixed    Centrifugal   Separators. — The  accompanying  illustration  shows  a  scrubbing 
tank  designed   to    be    more    efficient    per    unit     of    volume    and    weight   than   the 


ClliH0*<c*i. 


- 

J  " 

FIG.  29. — Latta  Stratification  Washer. 


FIG.  30. — Fixed  Centrifugal  Separator 


ordinary    coke    scrubber,    therefore    especially    amenable    to    marine    service.      The 
scrubber  is  designed  to  accomplish  the  following  functions  of  gas  purification: 

a.  Reversion  of  flow. 

b.  Change  of  direction. 

c.  Change  of  volume. 

d.  Impingement. 

e.  Baffling. 
/.  Scrubbing. 

g.  Concentration. 
h.  Centrifugal  action. 

The  gas  entering  the  scrubber  centrifugally  through  a  central  pipe  is  carried  down 
through  one  of  the  spiral  vanes,  being  met  by  a  spray  of  water  falling  from  above. 


64 


GAS   PRODUCERS 


The  spiral  vanes  have  the  tendency  of  an  inverted  cone  to  constrict  or  throttle 
the  flow  of  the  gas  and  concentrate  it  within  a  comparatively  small  area  at  the  bottom 
of  the  cone,  whence  the  water  falling  from  above  in  this  compressed  or  condensed 
form  will  have  a  peculiarly  severe  scrubbing  action. 

At  this  point  the  flow  of  the  gas  reverts  upward,  at  first  expanding  into  the 
upper  tank,  its  spiral  and  upward  motion  maintains  the  gas  in  rotation  with  a  con- 
sequent centrifugal  action,  the  tendency  of  the  gas  being  again  to  be  reduced  in 
volume  and  throttled  towards  the  outlet,  where  a  second  spray  falls  upon  it  in  its 
concentrated  form. 

Reversed  Current. — This  type  of  separator  has  many  examples  and  is  used  for 
many  purposes,  where  baffling  plates  and  settling  chambers  are  used.  The  following 
will  illustrate  the  principle. 


*~~^. 


£-  _ 


Moisture  CeilectcT 


FIG.  31. — Steam  Separator  used  as  Moisture 
Remover. 


FIG.  32.— Examples  of  Baffling  Separation,  the  dust 
or  moisture  being  deposited  by  the  reversal  of 
direction  of  flow. 


Condensing  Blast  Moisture. — The  removal  of  moisture  by  dehydrating  the 
air  very  considerably  diminishes  the  amount  ordinarily  requisite.  This  dehydration 
is  usually  performed  by  refrigeration,  the  air  being  reduced  to  about  28°  F.,  the 
reduction  usually  being  about  80°  F. 

This  reduction  in  temperature,  in  one  instance  known  to  the  writer,  lowered 
the  moisture  content  from  5.66  to  1.75  grains  of  moisture  per  cubic  foot.  In  one 
furnace  with  a  capacity  of  350  tons  of  iron  per  day,  with  a  coke  consumption  of 
2147  Ibs.  per  ton  of  iron  output,  and  using  approximately  40,000  cubic  feet  of  air 
per  minute,  two  ammonia  compressors  working  with  a  nominal  capacity  of  225 
tons  of  ice  each,  constituted  the  equipment,  but  one  was  usually  used  as  a  relay  or 
stand-by,  except  under  conditions  of  excessive  humidity. 


CLEANING   THE    GAS  65 

The  air  condensed  by  a  drop  of  temperature  was  reduced  to  34,000  cubic  feet 
per  minute,  the  output  increased  to  450  tons  of  iron,  with  a  coke  consumption  of  1,729 
Ibs.  per  ton  output,  the  blower  slowed  from  114  to  96  revolutions  per  minute  indi- 
cated horsepower,  consequently  reducing  from  2700  to  2013,  thereby  saving  687  h.p. 
The  refrigerating  apparatus  requiring  530  h.p.  there  was  a  net  saving  in  power 
amounting  to  157  h.p.,  in  addition  to  the  reduction  of  fuel  and  the  increase  of  output. 
In  this  instance,  as  cited  by  Dr.  J.  H.  Hart,  the  amount  of  moisture  collected  per 
day  amounted  to  ten  tons  of  water. 

In  addition  to  the  advantages  mentioned,  it  is  well-known  fact  that  dry  blast 
air  means  dry  gas  or  higher  flame  temperature.  Moreover,  the  gas  is  cleaner  and 
better  in  every  respect  for  both  hot  stove  and  engine  apparatus.  The  experiments 
and  comparisons,  both  in  America  and  abroad,  have  proven  that  the  increased  value 
and  efficiency  of  this  gas  alone  warrants  the  pie-drying  of  blast  air  for  furnaces. 

The  principal  drawback  \vith  blast  furnace  gas  lies  in  its  variability,  its  calorific 
value  varying  from  80  to  100  B.T.U.,  but  it  is  rarely  constant  at  the  maximum  value, 
and  for  purposes  of  calculation  it  is  best  estimated  at  the.  other  extreme.  The  cause 
of  its  variation  lies  principally  with  leaks  in  the  furnace  or  channels  through  the 
furnace  producing  over- ventilation  and  high  C02;  leaky  tuyeres  and  broken  water 
jackets,  with  an  attendant  escape  of  large  quantities  of  water  into  the  furnace,  both 
deaden  the  fires  and  produce  a  large  hydrogen  content.  It  is  largely  due  to  these 
variations  that  the  reliability  of  blast  furnace  gas  has  been  so  far  discredited  in  this 
country. 

To  correct  these  faults  there  are  a  number  of  patents  covering  processes  for 
the  recarburation  of  blast  gas  by  passing  it  through  additional  retorts  or  strata  of 
incandescent  fuel. 

Blast  furnace  gas  is  delivered  by  a  fan  to  boilers,  hot  stoves,  furnaces,  or  engines 
usually  at  a  pressure  of  from  2  to  4  inches  of  water. 

Eckel  is  authority  for  the  statement  that  ore-dust  to  the  amount  of  15%  or 
more  of  the  furnace  charge  (equivalent  to  from  25  to  50  tons  per  furnace  per  day), 
is  sometimes  carried  out  from  a  furnace  by  the  blast. 

For  a  plant  requiring,  say,  15,000,000  cu.ft.  of  air  per  twenty-four  hours,  a  mul- 
tiple or  factor  of  same  being,  roughly  speaking,  proportional;  a  reduction  of  tem- 
perature from  85°  to  26°-28°,  humidity  calculated  at  80%  saturation,  there  would 
be  required  an  equipment  consisting  of  two  batteries  of  direct  expansion  pipe  in 
coils,  of  15,000  feet  of  2-inch  pipe,  having  separate  expansion  shut-offs,  and  other 
connections  for  use  separately  or  in  multiple,  the  former  being,  in  cases  of  low 
load  or  during  continuous  operation,  to  permit  coils  to  be  defrosted  or  re- 
paired. 

Also  an  ammonia  compressor,  or  compressors,  to  be  the  equivalent  of  a  com- 
pressor cylinder  18-inch  bore  and  30-inch  stroke,  the  condenser  being  atmospheric 
in  six  sections  of  24  2-inch  pipes  20  feet  long. 

The  compressor  should  be  driven  by  a  125  h.p.  220  v.d.c.  motor  running  at  700 
r.p.m.,  belt-connected. 

The  total  cost  of  the  foregoing  plant,  as  estimated  upon  by  several  ice  machinery 
companies,  is  between  $20,000  and  $22,000  erected  complete. 

Where  the  by-product  gas  from  blast  furnaces  is  used  for  power  purposes  the 


66 


GAS   PRODUCERS 


quality  and  uniformity  of  the  gas  for  such  apparatus  is  notably  improved  by  the 
dehydration  of  the  air. 

This  is  due  to  the  prevention  of  deadening  of  the  fire  or  the  creation  of  spots, 
with  a  consequent  reduction  of  C02,  more  even  heat  which  subtends  an  advantage 
in  both  quality  and  quantity  of  the  ensuent  gas,  and  the  reduction  of  hydrogen,  which 
is  invariably  a  disadvantage  in  this  character  of  gas  when  used  for  power  purposes. 

In  fact,  under  these  conditions  the  gas  product  of  the  blast  furnace  would  be  an 
almost  perfect  fuel  for  engine  purposes,  were  it  not  for  the  tendency  of  water  jackets 
and  the  water-cooled  tuyeres  to  leak,  permitting  the  escape  of  water  and  steam  into 
the  furnace  with  an  ensuent  production  of  both  H  and  CO2. 


FIG.  33. — Tower  Scrubbers  in  Series. 

Tower  Scrubbers. — This  type  of  wet  scrubber  is  already  well  known  in  coal- 
gas  manufacture,  so  that  extended  description  is  not  necessary.  Instead  of  filling 
with  coke-trays,  or  similar  material  over  which  the  water  trickles,  one  of  the  more 
recent  producer-gas  plant  ideas  is  a  number  of  interior  water  sprays  or  misting  jets. 
The  capacity  may  be  increased  100%  by  increasing  the  water  supply.  The  spray 
nozzles  of  these  misting  jets  are  an  interesting  development. 

Bottom  trays  in  scrubbers  connected  with  down-draft  apparatus  should  be 
metal  (preferably  cast  iron)  to  resist  high  heat  of  gases  upon  entering  and  possible 
danger  of  ignition  through  carelessness  in  opening  water  pipes.  It  is  also  a  practice 
of  some  engineers  to  heat  up  the  coke  or  wood  contents  of  these  scrubbers  by 
turning  in  gas  without  the  use  of  water  sprays,  and  flood  the  tower  with  a  view  to 
removing  deposits  through  the  overflow.  The  value  of  this  method  is,  however, 
doubtful. 


CLEANING   THE   GAS 


67 


FIG.  34. — Tower  Scrubbers  in  Part 
Section. 


FIG.  35.— Tower  Scrubbers  Filled  with 
Coke  or  Excelsior. 


8-fX'plPE  FLAN6ES 


s«- 


I 

• 

5, 


, 


10  PIPE  PLUG 


nrrnnnnnnnnnnrrnnnnnnnr 


MANHOLE 
*"V\  " 

^jh    K£rr*TC 


v  CO   U 


,Z 

U"X 

J        «» 


FIG.  36. — Film  Tower  Scrubber. 


FIG.  37. — Misting  Spray  Scrubber. 


68 


GAS   PRODUCERS 


Cast-iron  scrubbers  are  better  than  steel  scrubbers  as  they  are  not  as  susceptible 
to  the  action  of  the  sulphuric  acid  when  the  sulphur  is  high  in  the  coal.  They  are 
more  advisable  for  use  with  salt  water,  also  when  scrubber  water  is  used  over  and 
over. 

Sprays.— The  essential  qualities  for'  sprays  consist  in  (a)  uniform  distribution, 
(6)  freedom  from  stoppage  or  clogging/  (c)  dispersion  of  the  water  into  the  finest 
possible  particles. 

The  reason  for  the  first  two  requisites  is  obvious,  for  the  second,  because  of 
the  fact  that  there  is  a  tendency  upon  the  part  of  all  gases  to  channel  through  and 

to  be  channeled  through  by  any  opposing 
current  of  gas,  vapor  or  water,  hence 
the  more  complete  the  vaporization  the 
more  thorough  the  intermingling  con- 
sequent, and  the  more  intimate  the 
mixture. 

Such  intermixture  has  a  tendency, 
as  already  described,  to  supersaturate 
and  weigh  down  foreign  matter,  besides 
dissolving  the  bubbles  and  globules  to 
a  point  where  they  gravitate  and  pre- 
cipitate. 

A  mist  spray   is    herewith  shown, 


FIG.  38. — Section  of  Misting  Spray  Scrubber. 


FIG.  39.— Water  Misting  Spray. 


which  gives  a  high  degree  of  vaporization  through  the  mutual  impingement  of  the 
two  nozzles. 

The  umbrella  sprays  are  particularly  free  from  stoppage  and  uniform  in  dis- 
tribution, although  their  misting  qualities  do  not  compare  with  the  impinging  jets. 
It  is  designed  to  be  made  with  a  brass  regulating  baffle  of  the  semi-spiral  type,  whose 
degree  of  throttling  compensates  for  the  water  pressure  and  also  the  area  over  which 
the  spray  is  delivered. 

This  spray  has  been  known  to  give  fairly  good  results  under  a  water  head  of 


CLEANING  THE   GAS 


69 


FIG.  40. — Spray  Nozzle. 


FIG.  41. — Another  Form  of  Spray  Nozzle. 


70 


GAS   PRODUCERS 


5  or  6  feet,  a  very  necessary  quality  under  some  conditions  and  directly  opposed  to 
the  misting  spray,  which  requires  a  minimum  of  60  Ibs.  pressure,  and  is  most  effective 
at  100  Ibs. 

While  the  umbrella  sprays  are  usually  used  for  the  tops  of  scrubbers,  etc.,  the 
misting  sprays  are  particularly  effective  when  interposed  in  pipe  lines  and  are  much 
used  in  this  manner  in  the  cleaning  of  blast  furnace  gas. 


FIG.  42. — Umbrella  Spray  Nozzle. 

Scrubber  Water. — Regarding  the  matter  of  purifying  water  for  scrubbers  and 
condensers  in  the  purification  or  cooling  of  producer  gas,  where  such  water  comes 
in  direct  contact  with  the  gas,  it  must  necessarily  become  foul,  and  inasmuch  as  the 
amount  of  water  necessary  is  comparatively  large,  the  facilities  for  or  cost  of  it  may 
become  an  important  item,  so  that  it  is  necessary  sometimes  to  recuperate  or  recover 
such  water  for  reuse,  merely  using  insufficient  fresh  water  to  compensate  for  the 
evaporation  taking  place. 

Where  this  is  the  case  settling  tanks  are  advisable,  in  connection  with  which 
there  should  be  used  a  baffle  separator,  as  herewith  illustrated.  The  last  sections 
of  this  separator  should  contain,  as  indicated,  a  bed  of  broken  coke,  to  which  in 
some  instances  may  be  added  a  screen  of  jute  or  cotton  bagging. 

This  will  be  found  to  purify  the  water  for  all  practical  purposes,  either  for  further 
use  or  to  meet  the  requirements  of  public  drainage.  For  circulation  an  iron  pump 
should  be  used  whose  packing  will  resist  the  action  of  the  hot  water  and  to  some 


CLEANING  THE   GAS 


71 


extent  acids  and  sulphurous  compounds.     A  brass-lined  ball-valve  pump  with  large 
ports  will  be  found  most  effective. 

A  careful  disposal  of  all  scrubber  water  or  drainage  water  in  gas  apparatus 
should  be  made.  In  allowing  it  to  escape  in  ordinary  sewage  systems,  care  should 
be  taken  of  the  ultimate  contamination  of  streams,  as  such  water  is  destructive  to 
animal  life,  especially  fish,  and  is  also  extremely  detrimental  to  metallic  substances. 


FIG.  43. — Baffling  Separator. 

In  this  connection,  even  a  small  contamination  is  most  injurious  to  feed  water  for 
boilers,  its  corrosive  action  upon  tubes  and  shells  being  very  severe. 

The  amount  of  water  per  horsepower  used  by  scrubber  on  a  suction  plant  is 
given  as  follows  by  one  of  the  largest  American  manufacturers: 

"  Our  suction  gas  plant  pamphlet  gives  this  as  one  gallon  per  horsepower  per 
hour,  but  we  have  since  discovered  that  this  is  in  error  and  will  be  corrected  in  a 
new  issue  of  the  pamphlet.  As  an  answer  to  this  question  often  affects  the  water 
supply  that  the  purchaser  will  allow,  we  would  state  that  it  is  advisable  to  tell  the 
purchaser  to  provide  for  seven  gallons  for  the  entire  use  of  the  suction  plant  per 
b.h.p.  hour,  figured  at  a  temperature  of  60°.  This,  in  our  opinion,  will  give  about 
twice  as  much  water  as  required,  but  ample  provision  should  be  made  in  all  installa- 
tions to  have  sufficient  water." 

Wash  Box  and  Seals. — The  action  of  the  wash-box  or  seal  is  largely  similar 
to  that  of  a  check  valve,  to  prevent  the  return  of  the  gas  to  the  apparatus.  These 
seals  are  generally  made  with  a  ratio  between 
the  wash-box  and  the  dip-pipe  areas  of  about 
25  to  1.  It  will  therefore  be  obvious  that 
if  the  dip-pipe  dips,  say  3  inches  in  the  water  of 
the  wash-box,  it  will  require  but  the  rise  of  3 
inches  of  water-pressure  to  force  the  gas 
through  the  seal,  while  before  the  gas  can 
return  from  the  box  into  the  dip-pipe  all  the 
water  in  the  box  would  have  to  be  forced 
back  into  the  dip-pipe.  Taking  the  area  ratio  of 
25  to  1,  as  before  mentioned,  while  it  takes  but 
three  inches  of  pressure  to  force  the  gas  into  the 
box,  it  would  require  3  X  25  =  75  inches  pressure 
to  force  the  gas  back  into  the  dip-pipe.  These 
figures  are  only  approximate.  This  same  prin- 
ciple can  be  observed  at  a  coal  gas  works  in  the  action  of  the  hydraulic  main. 

Receiver  Tanks. — A  receiver  tank  such  as  that  herewith  illustrated  performs 
the  dual  function  of  separating  the  moisture  mechanically  entrained  in  the  gas  by 


FIG.  44.— Water  Seal. 


72 


GAS   PRODUCERS 


means  of  stratification  or  gravity,  and  also  the  maintenance  of  an  ample  supply  of 
gas  close  to  the  engine  and  ready  for  its  immediate  demand.  This  arrangement  is 
particularly  advantageous  on  rapidly  shifting  loads,  inasmuch  as  it  maintains  a 


FIG.  45. — Receiver  Tank  and  Moisture  Collector. 

supply  ready  for  the  momentary  demand,  and  also  tends  to  prevent  the  hammer 
or  pulsation  in  the  gas  line  due  either  to  the  cutting  off  of  the  engine  valves  or  the 
rotation  of  the  blower,  there  being  a  strong  cushioning  •  effect.  In  some  circum- 
stances this  receiver  would  be  found  even  more  efficient  than  a  dry  scrubber,  which 
in  many  installations  it  has  superseded. 


CLEANING   THE   GAS  73 

TAR  EXTRACTORS 

The  tar  found  in  producer  gas  is  a  product  of  the  distillation  zone  of  the  pro- 
ducer, the  hydrocarbons  being  distilled  from  the  coal  in  most  part  at  a  low  tempera- 
ture, and  vary  very  much  in  their  gravity  and  nature,  running  all  the  way  from  the 
lighter  illuminants  to  the  very  heaviest  coal  oils.  The  passage  of  this,  tar  is  a 
mechanical  one,  the  gas  holding  it  in  various  amounts  at  various  temperature  or 
various  degrees  of  vapor  tension  and  pressure. 

Although  there  is  a  constant  tendency  for  gas  to  deposit  this  tar,  produced  by 
mechanical  friction,  kinetic  action,  and  reduction  of  temperature,  the  final  precipi- 
tation of  the  tar  seems  to  occur  most  critically  at  a  point  about  or  below  120°  F. 

Not  only  do  these  tars  appear  in  the  form  of  globules,  but  in  some  instances  in 
a  finely  divided  mist  known  as  "  tar  fog."  This  tar  fog  has  a  tendency  to  entrain 
other  foreign  matter,  hence  stoppages  along  pipe  lines  and  the  mixing  valves  of 
engines  occur,  which  are  formed  not  only  of  hydrocarbon  constituents,  but  of  par- 
ticles of  coal  ash  and  iron  with  their  various  oxides,  and  also  sulphur  compounds. 

The  methods  of  removing  this  tar  from  a  gas  may  be  divided  into  three  parts, 
the  latter  two  being  practically  identical  in  principle  though  reversed  in  accom- 
plishment. 

The  first,  by  washing,  has  the  dual  purpose  of  cooling  the  gas  and  lowering  the 
dew  point  of  precipitation,  and  also  by  supersaturating  the  tar  fog  or  mist  with 
water,  and  increasing  its  specific  gravity  or  weight  to  such  a  point  that  it  falls 
through  gravitation.  In  other  words,  the  tar  globules  take  up  and  entrain  enough 
water  to  precipitate  themselves  by  their  own  weight  or  that  of  the  combined  mass. 

The  second  and  third  methods  are  respectively  those  of  baffle  plates  or  mechan- 
ical separators,  the  motive  in  each  being  the  use  of  centrifugal  force.  That  is  to 
say,  the  weight  of  the  tar  being  greater  than  that  of  the  gas,  centrifugal  force  tends 
to  crowd  it  to  the  outer  edges  of  the  passage,  where  it  impinges  upon  and  adheres 
to  these  baffles  by  reason  of  its  own  weight.  Moreover,  the  inertia  of  the  tar  being 
greater  than  that  of  the  gas,  it  does  not  follow  lines  of  diversion  with  the  same 
rapidity,  and  is  therefore  more  easily  impinged  upon  the  baffles.  In  the  centrifugal 
separator,  the  difference  in  weight  of  the  tar  globule  and  the  gas  is  the  sole  principle 
involved. 

Comparison  of  Tar  Extractors. — This  subject  is  treated  by  R.  H.  Clayton  and 
F.  W.  Skirrow  in  the  London  Journal  of  Gas  Lighting  (June  4,  1907).  Although 


* -vvv ffife 


FIG.  46.— Filter  used  in  Testing  for  Tar. 

used  primarily  in  connection  with  the  removal  of  impurities  from  coal  gas,  yet  the 
comparisons  drawn  are  all  of  an  analogous  nature  and  useful  in  a  general  discus- 
sion of  the  subject. 

A   series   of   experiments   was   first    made   to   obtain    a   satisfactory   method   of 
stimating  the  tar  fog  carried  along  in  the  gas.     This  was  done  by  inserting  in  the 


74 


GAS   PRODUCERS 


pipe  a  glass  filtering  tube  f-inch  in  diameter,  with  a  ^-inch  hole  in  the  side  facing 
the  flow  of  gas.  The  inner  end  of  the  tube  is  closed,  and  its  length  is  such  that  the 
hole  is  exactly  two-thirds  of  the  wray  across  the  main.  The  tube  contains  about 
12  inches  of  lightly  packed  cotton  wool,  care  being  taken  that  all  that  part  of  the 
tube  containing  the  cotton  wool  is  in  the  main.  Generally  20  to  30  feet  of  the  gas 
are  taken.  The  tar  is  determined  by  washing  the  cotton  with  carbon  bisulphide 
and  evaporating. 

At  the  works  in  question  a  Kirkham  and  a  Clapham  washer  were  worked  in 
parallel.  Simultaneous  determinations  showed  that  while  the  average  tar  at  the 
inlet  was  1.5  grams  per  100  cubic  feet,  that  at  the  outlet  of  the  Clapham  was  1.3 
grams,  and  at  the  outlet  of  the  Kirkham  washer  was  1.45  grams,  the  temperature 
60  to  74°  F.  Similar  tests  made  on  Livesey  washers  at  other  plants  showed  that 
at  73  to  86°  F.  between  84  and  88%  of  the  tar  fog  was  removed,  showing  that 
this  is  not  a  very  perfect  form  of  extractor. 

The  next  type  examined  was  a  P.  &  A.  tar  extractor.  This  was  found  to  remove 
98%  of  the  tar  temperature  ranging  from  72  to  88°  F.  Next  was  tried  the  effect 
of  varying  the  differential  pressure,  with  the  result  as  here  shown: 


Tar  per  100  Cubic  Feet. 

Differential 
Pressure. 

Temperature 
(Inlet). 

Purification. 

Inlet. 

Outlet. 

4.75  ins. 

72.5deg. 

11.33gr. 

0.126gr. 

98.9% 

4.62 

62.0 

15.21 

0  .  133 

99.1% 

4.50 

65.0 

15.54 

0.156 

99.0% 

4.75 

81.0 

11.72 

0.185 

98.4% 

4.81 

83.8 

12.89 

0.155 

98.8% 

2.00 

71.2 

15.00 

0.421 

97.2% 

1.50 

69.0 

10.98 

4.890 

55.4% 

1.50 

68.0 

11.05 

3.410 

69.2% 

Below  a  differential  of  2  inches  the  machine  ceases  to  work  efficiently.  Since 
the  volume  of  gas  passed  is  proportional  to  the  square  root  of  the  head,  with  reduced 
pressure,  the  number  of  holes  would  have  to  be  very  largely  increased,  and  the  cage 
would  have  to  be  raised  so  far  out  of  water  that  the  seal  would  be  broken  and  the 
gas  would  be  by-passed. 

It  would  appear  that  the  temperature  did  not  exercise  as  great  an  influence 
as  might  have  been  expected,  for  as  great  an  efficiency  was  obtained  at  low  as  at 
high  temperatures.  According  to  other  observers,  however,  the  temperature  should 
be  kept  at  about  80°  F.,  so  that  the  tar  remains  thin  and  the  plates  clear  themselves. 
Another  point  to  be  noted  is  that  the  tar  at  the  outlet  is  independent  of  the  quantity 
entering  the  machine  within  the  limits  of  the  experiment. 

On  trying  the  P.  &  A.  extractor  with  water  gas  it  was  found  that  the  plates 
within  a  few  days  pitched  up,  leading  to  the  conclusion  that  the  present  form  could 
not  give  the  desired  result.  On  considering  the  greater  difficulty  presented  in 
removing  tar  from  water  gas  than  from  coal  gas,  the  writers  arrived  at  the  idea  that 
the  problem  was  similar  to  that  presented  in  operating  gas  engines  from  soft  coal 


CLEANING   THE   GAS 


75 


producers.  Inquiry  brought  out  the  fact  that  in  all  cases  purification  by  centrifugal 
force  had  been  adopted.  It  being  impossible  to  learn  the  efficiency  of  this  method 
by  questions,  the  writers  decided  to  test  this  method  for  themselves. 

The  tests  were  made  with  the  ordinary  fan  and  the  Crossley  fan.  The  first 
revolved  at  from  1500  to  2000  revolutions.  The  gas  entered  at  the  center,  and  a 
jet  of  water  was  introduced  at  the  same  time  to  the  amount  of  1  gallon  per  80  cubic 
feet.  The  gas  left  the  machine  at  an  increased  pressure  of  2  or  3  inches. 

The  Crossley  fan  was  designed  for  the  special  purpose  of  gas  purification  and 
does  not  increase  the  pressure.  It  consists  of  a  revolving  disk  in  a  casing.  The  gas 
enters  one  side  at  the  center,  passes  to  the  periphery,  absorbing  much  power,  and 
then  flows  down  the  opposite  side  to  the  outlet  at  the  center  on  that  side,  returning 
the  power  absorbed.  The  total  power  is  said  to  be  but  3  or  4  h.p.  per  5,000,000 
cubic  feet  per  day.  One  gallon  of  water  was  used  in  this  machine  per  1000  cubic 
feet,  to  flush  out  the  tar  and  prevent  clogging.  The  fan  tested  had  a  diameter  of 
9  feet,  ran  at  400  revolutions,  and  had  a  nominal  capacity  of  5,000,000  cubic  feet 
per  day.  The  power  required  is  about  the  same  as  is  required  for  driving  gas  through 
a  P.  &  A.  extractor. 

Having  no  opportunity  for  testing  this  machine  on  water  gas,  the  authors  had 
to  content  themselves  \vith  observing  its  efficiency  with  producer  gas  and  on  but 
half  its  capacity.  The  results  are  herewith  shown: 


No. 

Flow  of  Gas, 
1000's  cu.  ft. 
per  Hour. 

Temperature, 
Fahrenheit. 

Tar,  Grams  per  100  Cubic  Feet. 

Purification, 
per  Cent. 

Inlet. 

Outlet. 

1 

60 

3.8 

0.426 

89.0 

2 

50 

75 

13.8 

0.458 

96.7 

3 

50 

84 

26.5 

0.690 

97.4 

4 

100 

83 

9.36 

0.570 

93.9 

In  tests  No.  2  and  3  the  preliminary  washers  were  by-passed,  and  in  No.  4  one 
of  the  coolers  was  out  of  action. 

Determinations  of  the  tar  in  water  gas  showed  from  10  to  13  grams  per  100  cubic 
feet  at  the  inlet  of  the  purifier.  If  we  assume,  and  there  is  every  justification  for 
doing  so,  that  the  fans  will  be  as  efficient  as  with  producer  gas,  we  should  not  only 
remove  about  95f/c  of  the  tar,  but  recover  it  in  a  salable  form.  The  small  amount 
left  in  the  gas  could  economically  be  removed  with  a  sawdust  scrubber. 

Mallets'  rotary  tar  extractor,  in  use  in  some  continental  gas  works,  comprises 
plates  built  up  as  a  revolving  drum,  the  lower  half  of  which  dips  into  condensed 
tar  in  the  bottom  of  the  casing.  The  differential  pressure  is  regulated  by  raising 
and  lowering  the  tar  level.  The  temperature  giving  best  results  is  from  80°  to  85°  F., 
and  at  a  differential  of  2.5  to  3  inches,  the  efficiency  is  said  to  be  equivalent  to  a 
reduction  in  the  tar  of  from  13  to  6  grams  of  tar  down  to  0.18  to  0.04  gram  per  100 
cubic  feet. 

Stationary  Tar  Extractors,  Centrifugal. — Although  many  centrifugal  tar  extractors 
require  power,  as  they  revolve  and  act  by  centrifugal  force  upon  the  tar  particles, 


76 


GAS   PRODUCERS 


in  the  invention  to  be  described,  there  are  no  moving  parts  whatever,  as  such  motion 
is  imparted  to  the  gas  as  to  cause  the  tarry  particles,  globules,  or  vesicles  which 
have  a  greater  density  than  the  gas,  to  be  immediately  forced  against  the  interior 
surfaces  of  the  apparatus,  and  thus  be  subjected  to  the  necessary  friction  and  impact. 

Not  only  is  it  the  object  of  the  present  invention  to  remove  the  tar,  which  in 
its  pure  state  is  composed  entirely  of  a  number  of  hydrocarbons  of  varying  density, 
but  also  to  remove  any  solid  matter  suspended  in  or  carried  by  the  gas  in  the  shape 
of  impurities. 

Referring  to  the  figure,  the  gas-main  has  inserted  within  its  length  a  trap, 
while  at  the  opposite  sides  of  the  trap  and  connected  with  the  main  are  elbow- 


FIG.  47. — Fixed  Centrifugal  Tar  Extractor. 

couplings  which  are  controlled  by  means  of  suitable  valves.  From  the  couplings 
extend  branch  pipes  or  conduits  which  at  their  outer  ends  are  connected.  By 
means  of  the  valves  the  by-passing  of  the  gas  around  the  columns  is  controlled. 
Suitably  secured  within  the  ends  of  the  pipe  are  spiders  or  skeleton  frames  in  central 
sockets  of  which  are  inserted  the  tubular  shaft  of  the  screw.  This  shaft  is  closed 
at  its  upper  end  and  is  open  at  its  lower  end,  where  it  communicates,  by  means  of 


CLEANING  THE   GAS 


77 


branches  forming  a  tar  seal  with  a  discharge-pipe.  The  screw-blade  slants  toward 
the  center,  forming  inverted  cone-shaped  surfaces  over  which  the  liquid  may  run  in 
all  directions  toward  the  center,  and  the  edge  of  the  blade  is  in  contact  with  the 
inner  cylindrical  surface  of  the  pipe  or  conduit.  Small  holes  or  perforations  are 
made  in  the  tubular  shaft  or  axis  of  the  screw,  so  that  the  tar  which  is  deposited 
on  the  blade  and  the  inside  surface  of  the  pipe  or  conduit  may,  after  first  flowing 
down  to  the  tube,  pass  through  the  said  holes  or  perforations  and  down  the  interior 
of  the  tube.  A  suitable  dam  is  formed  behind  each  hole  for  the  purpose  of  causing 
the  tar  to  dam  up,  and  thus  be  forced  into  the  holes.  As  there  is  a  differential 
pressure  in  the  gas  between  the  top  and  bottom  parts  of  the  screw,  a  small 
amount  of  gas  will  leak  into  the  tube  through  the  holes  or  perforations  at  the  bottom 
and  out  of  the  holes  at  the  top. 

The  water  seal  referred  to  is  provided  with  two  water-gauge  glasses,  to  show 
the  different  heights  of  the  water  in  the  seal.  But  one  of  the  glasses  is  shown 
at  the  right-hand  side  of  the  seal.  A  pipe  at  the  bottom  of  the  water  seal  is 
connected  with  the  same,  and  is  provided  at  opposite  sides  "of  the  said  connection 
with  valves.  One  valve  is  to  be  connected  to  water-supply  under  pressure,  while 
the  other  valve  is  connected  to  waste.  By  opening  one  valve  for  instance,  the 
water  in  the  seal  can  be  entirely  withdrawn,  while  by  closing  this  valve  and  opening 
the  other  valve  the  water-level  in  the  seal  can  be  increased.  The  object  of  the 

described  water  seal  is  to  prevent  any  undue 
back  pressure  of  gas  in  case  the  pipe  should 
become  stopped  up,  and  it  therefore  forms  an 
automatic  by-pass. 

The  described  apparatus  can  be  employed 
either  with  coal-gas  or  water-gas  plants  for 
the  removal  of  tar  or  other  solid  matter  form- 
ing impurities. 

P.  &  A.  Baffling  Extractors. — This  is  another 
form  of  stationary  extractor.  Where  used  in 
intermittent  service,  it  must  be  kept  as  nearly 
as  possible  at  a  constant  temperature,  usually 
between  120  and  100°  F.  This  is  for  the  reason 


FIG.  48.— Elevation  of  the  P.  &  A.  Tar 
Extractor. 


FIG.  49.— Plan  of  P.  &  A.  Tar  Extractor  showing 
connections. 


that  during  stand-by  periods  a  certain  amount  of  sediment  upon  the  plates  has  a  ten- 
dency to  congeal,  due  to  a  cooling  influence  on  the  part  of  the  separator  itself  and 


78 


GAS    PRODUCE US 


its  water  seal,  the  result  is  that  the  plates  become  "  gummy,"  and  create  a  nucleus 
which,  upon  starting  up  the  separator  again  entrains  further  stoppage  and  in  a  short 
time  puts  the  apparatus  out  of  commission.  The  temperature  of  the  condenser 
should  at  no  time  get  lower  than  100°  F.  The  easiest  way  would  be  to  have  a 
steam-pipe  attachment  and  turn  on  a  little  steam  into  the  separator  during  stand-by 
periods. 

The  accompanying  illustration  shows  what  this  extractor  looks  like.     The  gas 
passes  through  small  holes  and  impinges  on  surfaces  to  which  the  tar  sticks.     Gas 


TKR  COLLECTOR 


DETAIL  OF 
DECLECTOR  FOR 
TAB  COLLECTOR 


FIG.  50.— Tar  Extractor. 

tar  remains  fluid  above  100  to  120°  F.,  below  which  it  becomes  sluggish  and  congeals. 

A  form  of  tar  collector  is  herewith  illustrated  resembling  the  P.  &  A.  in  principle, 
operating  upon  the  idea  of  impinging  jets.  This  type  is  advisable  only  in  exceptional 
instances. 

Centrifugal  Tar  Extractor. — Efficient  gas  cleaning  of  bituminous  gas  has  been 
demonstrated  in  the  blast  furnace  gas  power  plant  of  the  former  Carnegie  Steel  Co., 
at  Pittsburg,  Pa.  The  apparatus  comprises  a  combination  of  vertical  baffling  washers 
connected  in  series  with  a  centrifugal  rotary  scrubber.  This  apparatus  delivers  gas 
to  the  holder  in  a  condition  which  may  be  noted  as  absolutely  clean. 

A  fair  estimate  of  the  power  required  for  a  mechanical  tar  separator,  including 


CLEANING  THE   GAS 


79 


friction  of  line  shaft  and  other  losses,  may  be  placed  at  between  4  and  5%  of  the 
total  horsepower  of  the  plant. 

The  centrifugal  tar  separator  fitted  in  the  works  of  the  Allis-Chalmers  Co.,  at 


FIG.  51. — Vertical  Section  of  Centrifugal  Tar  Extractor. 

West  Allis,  Wis.,  has  proven  a  duty  of  separating  tar  from  producer  gas  at  the  rate 
of  300  Ibs.  of  net  tar  per  ton  of  coal  gasified. 

The   accompanying   section    illustrates   the    horizontal    cross -section  through   a 
centrifugal  scrubber,  and  this  illustrates  very  well 
this  type    of   separator,  useful   for    tar  as  well   as 
moisture  and  wet,  dust-like  impurities. 

The  location  for  the  tar  extractor  at  the  300 
h.p.  suction  producer  plant  of  the  Fort  Dodge 
(la.)  Light  and  Power  Co.,  is  shown  by  the  ac- 
companying drawing. 

In  soft-coal  practice  it  is  necessary  to  periodi- 
cally burn  out  the  tar  and  soot  deposited  by  the 
gas.  This  is  done  by  stopping  the  producer  and 
opening  suitable  doors  provided  in  the  flues. 
Usually  the  soot  takes  fire  readily,  or  may  be  ignited, 
and  the  furnace  stack  draws  the  air  and  combustion  through  the  flue.  In  some 
cases  direct  connection  of  the  flue  is  made  to  the  stack  and  air  or  steam  jets  used 
to  loosen  the  deposits  of  soot,  while  at  the  accessible  points  it  is  scraped 
out. 

Ordinarily,   tar  is  not   decomposed   below   a  temperature  of  2000°  F.,   although 
moisture  which  it  contains  may,  of  course,  be  evaporated  at  boiling-point 


FIG.  52. — Centrifugal  Tar  Separator. 


80 


GAS    PRODUCERS 


Gas  Engine  Requirements. — The  purity  of  gas  for  use  in  gas  engines  is  specified 
by  the  makers  of  those  engines  which  operate  on  producer  gas,  and  the  following 
are  some  examples: 

Snow  Steam  Pump  Co.:  They  have  experienced  little  trouble  from  moisture, 
the  single  exceptions  having  been  occasioned  not  from  moisture  in  the  gas,  but  from 
condensation  in  the  pipes  after  long  stand-by  periods.  This  may,  of  course,  be  over- 
come by  blowing  out  a  small  quantity  of  gas  through  the  engine  purge  pipes. 


FIG.  53. — Location  of  Tar  Separator,  Plan  and  Elevation. 


A  small  content  of  tar,  however,  creates  much  trouble,  occasioning  crematory 
stoppages  and  attendant  evils.  The  limit  permissible  should  not  exceed  0.01  grain 
per  cubic  foot,  mineral  dust  must  not  exceed  0.02  grain  per  cubic  foot,  and  the  total 
impurities,  including  lamp  black,  should  not  exceed  0.05  grain  per  cubic  foot. 

Westinghouse  Machine  Co.:  "A  producer  gas  containing  from  125  to  150  effec- 
tive B.T.U.,  but  the  gas  must  not  contain  more  than  170  effective  B.T.U.  They 
would  like  the  gas  to  be  in  accordance  with  the  following  analysis:  Not  to  contain 
more  than, 


CLEANING  THE   GAS  81 

0.01  grain  of  dust  per  cu.ft., 

0.15  grain  of  sulphur  per  cu.ft., 

0.02  grain  of  tar  per  cu.ft., 

4.00  grains  of  moisture  per  cu.ft.,  above  point  of  saturation,  and  not  to  contain 
more  than  15%  of  hydrogen  by  volume,  and  not  less  than  2%  of  methane  by  vol- 
ume. In  some  cases  we  have  found  it  impossible  to  get  the  producer  manufacturer 
to  comply  with  our  specifications  as  to  the  quality  of  gas,  but  the  above  limitations 
are  by  no  means  impossible  of  attainment." 

R.  D.  Wood  &  Co.:  They  make  the  following  guarantee  as  to  the  gas  sup- 
plied from  their  producer  for  engine  service:  That  gas  produced  shall  contain 
per  cubic  foot  not  in  excess  of  0.02  grain  of  tar;  0.0 1  grain  of  dust  and  6  grains 
of  moisture. 

Junge  states  in  his  work  on  Power  Gas:  "  It  must  be  remembered  that  even 
a  very  small  amount  of  dust  is  prohibitive  in  gas-engine  cylinders  as  it,  naturally 
gritty,  will  unite  with  the  lubricating  oil,  forming  a  pasty  mass  which  produces  an 
abrasive  effect  only  excelled  by  oil  and  emery.  As  75%  of  the  dust  is  metallic  oxide, 
when  subjected  to  a  temperature  of  300°  F.  (the  heat  of  inflammation)  it  will  be 
precipitated  as  iron  and  steel.  The  third  requirement  to  be  considered  is  freedom 
from  excessive  moisture.  When  the  gas  leaves  the  furnace  (we  are  now  speaking 
of  blast-furnace  gas)  it  is  laden  with  dust,  containing  8  to  15  grains  per  cubic  meter 
(4  to  7  grains  per  cubic  foot),  and  other  negligible  impurities,  and  is  very  hot  (140° 
to  180°  C.)  but  comparatively  dry.  The  greater  part  of  the  dust  is  first  removed 
by  a  dry  process  in  the  dust  catcher,  while  the  finer  particles  are  eliminated  by 
bringing  the  gas  in  intimate  contact  with  water.  Now  this  water,  leaving  aside  its 
varying  temperature,  represents  in  all  processes  an  almost  constant  amount  com- 
pared to  the  quantity,  temperature,  and  composition  of  the  gas  and  its  dust  con- 
tents, all  of  which  vary  according  to  the  course  of  the  smelting  process  and  the 
condition  of  the  season.  This  water  remains  suspended  in  the  gas  after  leaving 
the  scrubbers,  washers,  and  fans,  and  to  secure  regular  and  efficient  combustion  it 
must  be  removed  again  dowrn  to  a  very  low  percentage  before  being  conveyed  to 
heaters  and  engines. 

'  To  secure  maximum  efficiency  of  combustion  we  must  have  a  cool,  clean, 
dry  gas.  But  these  requirements  vary  in  degree,  according  to  the  manner  and  kind 
of  application.  For  use  in  hot-blast  stoves  and  under  boilers  the  temperature  of 
the  gas  may  be  higher  than  for  use  in  gas  engines.  But  higher  temperatures  enable 
the  gas  to  contain  a  large  amount  of  moisture,  which  is  again  harmful  to  the 
all-around  efficiency.  The  degree  of  purity  of  the  gas  for  heating  furnaces  need  not 
necessarily  be  higher  than  0.5  grain  of  dust  per  1  cubic  meter,  or  0.2  grain  per  cubic 
foot,  as  it  is  found  that  the  fire-brick  lining  of  the  ovens  is  apt  to  fuse  when  still 
higher  temperatures  are  maintained.  For  use  in  engines  there  are  no  lower  limits 
fixed  for  temperature  or  purity,  but  the  upper  limits  are  the  more  rigidly  drawn, 
namely,  temperature  25°  C.,  and  degree  of  purity  0.02  grain  per  cubic  foot.  The 
latter  figure  is  the  basis  on  which  German  manufacturers  give  their  guarantees  on 
gas  engines.  This  covers  the  case  as  far  as  temperature  and  purity  for  various  pur- 
poses are  concerned." 

Lacka wanna  Iron  Co.:    According  to  an  official  statement  made  by  the  Lacka- 


82  GAS    PRODUCERS 

wanna  staff  some  time  ago,  the  degree  of  purity  of  the  gas  that  can  be  reached  with 
this  cleaning  plant  was  shown  by  its  content  of  from  0.043  to  0.934  grain  (0.6663  to 
0.524  grain)  of  dust  per  cubic  meter  (35,314  cubic  feet). 

Sulphur  in  Engine  Gas. — Considerable  controversy  has  arisen  in  various  parts 
of  the  country  regarding  the  influence  of  sulphur  upon  the  cylinders  of  a  gas  engine, 
leading  in  some  cases  to  the  introduction  of  this  question  into  important  lawsuits. 
The  engine  in  use  at  the  testing  plant  of  the  United  States  Geological  Survey  has 
received  the  full  charge  of  sulphur  contained  in  the  gas,  since  the  establishment  of 
the  plant,  and  shows  absolutely  no  signs  of  injurious  effects,  although  coals  have 
been  used  running  as  high  as  8.1%  sulphur. 


CHAPTER  III 
WORKS   DETAILS 

Vaporizers. — The  subject  of  the  use  of  steam  versus  water  vapor  as  an  endo- 
thermic  agent  has  been  pretty  thoroughly  discussed  by  the  writer  under  the  head 
of  endothermic  agents.  It  seems  logical  that  the  heat  for  the  creation  of  this  steam 
or  vapor  should  be  recuperated  heat,  that  is  to  say,  should  not  be  obtained  at  the 
expense  of  fuel  consumption;  this,  as  far  as  power  plants  are  concerned,  must  logically 
be  from  the  sensible  heat  of  the  effluent  gases,  the  tendency  being  to  condense  the 
gas  and  also  restore  the  waste  heat  to  the  fire. 

With  producers  operated  in  connection  with  furnaces  the  utility  of  this  arrange- 
ment is  doubtful,  and  it  is  perhaps  best  to  utilize  direct  radiant  heat  of  the  fire  as 
in  No.  4,  as  an  absorption  of  the  sensible  heat  of  the  gases  in  this  connection  tends  to 
the  reduction  of  flame  temperature  in  final  combustion. 

Taking  up  vaporizers  for  power  purposes  further,  there  may  be  said  to  be  three 
distinct  types,  namely,  those  relating  to  the  evaporation  of  water  from  the  ash  pits, 
to  which  many  engineers  are  opposed  by  reason  of  the  cooling  effect  upon  the  ashes, 
thereby  preventing  the  radiation  of  their  heat  during  the  cooling  process  back  into 
the  furnace.  This  claim,  made  by  Mathot  and  other  German  engineers,  is  of  doubt- 
ful value,  inasmuch  as  recuperated  heat  from  the  cooling  ash  must  be  comparatively 
small  when  compared  to  the  loss  by  conduction,  also  there  is  considerable  benefit 
derived  from  the  humidifying  effect  of  vapor  thus  distilled  upon  the  grate  bars  which 
are  materially  cooled  thereb}'.  There  is  also  a  cooling  effect  upon  the  bottom  of  the 
fire  where  clinker  is  apt  to  collect  and  fuse,  or  in  common  parlance  to  "  slag." 

The  second  type  of  vaporizers  for  the  recuperation  of  sensible  heat  is  that  of 
the  multitubular  type  connected  with  the  take-off  pipe  of  the  producer  through  which 
the  effluent  gases  pass.  This  type  of  vaporizer  is  very  satisfactory  where  fuel  of  a 
non-bituminous  nature  is  used  or  where  the  effluent  gases  are  free  from  tar,  lamp- 
black or  unfixed  hydrocarbons. 

This  is  the  case  also  with  down-draft  apparatus  where  these  hydrocarbons  were 
fixed.  In  case  of  the  use  of  this  type  the  gas  should  be  admitted  at  the  bottom  of 
the  vaporizer  where  it  comes  in  contact  with  the  water  leg  of  the  tubes,  as  otherwise 
tubes  and  tube  sheets  cannot  withstand  the  temperature. 

Where  this  type  is  adopted  type  "  B  "  would  be  found  most  satisfactory  inas- 
much as  these  tubes  are  susceptible  to  operation  with  cleannig  or  scurfing  rings  after 
the  manner  of  an  economizer. 

For  general  apparatus,  however,  the  arrangement  shown  in  the  illustrations  will 
be  found  more  satisfactory;  these,  especially  Nos.  1,  2,  and  3,  are  designed  to  vaporize 

83 


GAS   PRODUCERS 


r- 


FIG.  54. — Water  Vaporisers  on  Producer. 


FIG.  55. — Producer  Economizers. 


WORKS   DETAILS 


85 


water  by  the  sensible  heat  of  the  effluent  gases  within  the  top  of  the  producer,  while 
leaving  the  producer  through  the  take-off  pipe. 

All  these  producers  receive  a  small  portion  of  radiant  heat  from  the  fire  and 
there  may  be  a  trifling  loss  of  heat  from  the  conduction  of  the  shell.  Such  losses 
are  comparatively  small  and  the  benefit  to  operation  derived  from  a  cool  producer 
top  and  their  accessibility  for  the  removal  of  scale,  etc.,  may  be  considered  a  stand-off. 

It  is  the  belief  of  the  writer  that  water  should  always  be  hand  regulated  to  pro- 
ducers, inasmuch  as  the  amount  of  water  required  varies  with  so  many  conditions 
that  it  is  impossible  to  confine  its  admission  as  a  reciprocal  of  any  one  condition. 

Gas 


/    /     /     /     t 


FIG.  56. — Powdered  Fuel  Producer  Economizer. 

A  small  water  content  can  be  constantly  kept  in  the  vaporizers  herewith  shown, 
or  again  the  steam  may  be  flashed  by  intermittent  admission.  The  latter  is  an 
excellent  arrangement. 

No.  3  shows  an  arrangement  whereby  the  steam  is  generated  in  a  small  return 
bend  coil  within  the  take-off  pipe,  a  sheath  or  sleeve  on  the  outside  of  the  take-off 
pipe  forming  a  pre-heater  for  the  incoming  air  and  absorbing  the  radiation  from  the 
outside  of  the  take-off  pipe  as  the  coil  absorbs  the  sensible  heat  of  the  gas  within  the 
pipe.  This  coil  has  the  advantage  of  being  easily  removed  and  cleaned,  and  is  also 
cheaply  renewed,  if  it  is  for  any  reason  destroyed  or  impaired. 

Within  all  up-draft  producers  the  gases  collect  in  the  take-off  pipe  and  top  of 
the  producer,  and  the  abstraction  of  heat  from  these  will,  under  most  conditions, 
make  all  the  steam  which  is  reouired. 


86 


GAS   PRODUCERS 


For  down-draft  producers,  or  producers  of  the  powdered-fuel  type,  completely 
fixing  their  hydrocarbons,  the  tubular  vaporizer  will  doubtless  be  found  most  effi- 
cient, as  shown. 

Charging  Producers. — One  of  the  most  convenient,  economical,  and  simple 
methods  of  charging  gas  producers  is  by  an  electric  storage  battery  locomotive  coal 
car,  running  on  an  industrial  railway,  specially  designed  for  handling  coal  from  the 


FIG.  57. — Economizer  for  Bituminous  Producer. 


storage  bins  to  gas  producers.  The  locomotive  runs  under  an  elevated  storage  bin, 
and  coal  is  loaded  into  the  larry  through  suitable  valves.  The  track  runs  over  the 
top  of  the  gas  producers,  into  which  the  locomotive  spouts  the  coal  direct.  The  coal- 
storage  bin  can  be  situated  in  any  convenient  position  where  the  tracks  can  reach 
them.  The  entire  operation  of  the  machine  requires  the  services  of  but  one  man. 

Pressure  boards,  consisting  of  series  of  glass  dip  pipes  for  approximate  determina- 
tion of  either  suction  or  pressure  at  different  points  of  the  apparatus  can  be 
installed  to  advantage  as  a. check  on  operation. 

Safety  Devices. — Blast  pipe  may  be  to  a  degree  protective  against  the  ignition 
of  gases  and  "  flare-backs  "  by  the  insertion  of  diagonal  or  conical  screens  of  larger 


WORKS   DETAILS 


87 


FIG.  58.— Coal  Car  ready  for  charging  Producer. 


FIG.  59. — Charging  a  Gas  Producer . 


FIG.  60. — Charging  a  Car  with  Coal. 


FIG.  61. — Suction  Gauge  Board. 


88  GAS   PRODUCERS 

area  than  the  pipe  section.  The  diagonal  form  is  used,  of  course,  to  increase  the 
area.  The  screen  should  be  made  of  brass-wire  gauze  not  larger  than  60  mesh  or 
its  equivalent. 

Wire-gauze  screens  or  caps  should  cover-  all  air-intake  piping  or  test-light  out- 
lets, where  connected  with  gas  apparatus  or  appliances.  Relief  valves  may  be  of 
three  types,  namely: 

a.  Swinging  valves  which  are  hinged  and  consist  of  blank  flanges  hinged  upon 
one  side  and  held  in  position  by  counter  weights. 


FIG.  62. — Screen  Preventing  Firing  back. 

b.  Water  seals  consisting  of  dip  pipes  sealed  in  water  to  a   depth  affording  a 
margin  of  safety.     And 

c.  Thin-lead  blank  flanges  whose  rupture  point  should  not  be  above  some  three 
or  four  pounds  pressure. 

It  is  preferable  that  all  of  these  devices  have  air  vents  leading  to  the  atmosphere, 
these  being  most  important  with  the  two  last-named  arrangements,  inasmuch  as  the 
seal  being  destroyed,  there  is  danger  of  gas  collecting  within  a  building  in  sufficient 
quantities  to  create  an  explosive  mixture.  This  danger  can,  in  some  degree,  be 
obviated  in  the  case  of  the  water  seal  by  equipping  it  with  a  continuous  water  supply 
and  overflow.  There  is,  however,  a  factor  of  danger  present  in  each  of  the  last- 
named  types,  and  the  swing  valve,  such  as  is  indicated  in  the  illustration,  of  a  blast- 
gas  dry  scrubber,  is  perhaps  the  safest  arrangement,  so  long  as  the  outlet  of  the  valve 
is  so  situated  that  it  cannot  impinge  during  a  blow  off  upon  either  the  operator  or  any 
inflammable  substance. 

Insurance  Requirements. — Underwriters  require  all  overflow  pipes  to  be  sealed 
with  at  least  twelve  inches  of  water.  Where  ash  pits  of  producers  are  sealed  with 
water,  the  bosch  must  be  continuously  overflowing.  Rule  2e  requires  the  use  of 
some  form  of  interfering  three-way  valve,  so  that  the  producer  is  always  open  either 
to  the  engine  or  to  the  outside  atmosphere. 

Pressure  Systems.  All  pressure  systems  must  be  located  in  a  special  building 
or  buildings  approved  for  the  purpose,  at  such  distance  from  other  buildings  as  not 
to  constitute  an  exposure  thereto,  excepting  that  approved  pressure  systems  with- 
out gas  holder,  having  a  maximum  capacity  not  exceeding  250  H.P.,  and  with  pres- 
sure in  generator  not  exceeding  two  pounds,  may  be  located  in  the  building;  provided 
that  the  generator  and  all  apparatus  connected  therewith  be  located  in  a  separate 
fire-proof  room,  well  ventilated  to  the  outside  of  the  building.  In  all  other  respects 
the  apparatus  must  comply  with  the  requirements  for  suction  systems. 


WORKS   DETAILS  89 

Suction  Systems.  The  1908  rules  of  the  National  Board  of  Fire  Underwriters' 
Engineers  for  suction  producers  are  as  follows: 

a.  A  suction  gas  producer  of  approved  make  having  a  maximum  capacity  not 
exceeding  250  H.P.   may  be  located  inside  the  building,  provided  the  apparatus  for 
producing  and  preparing  the  gas  is  installed  in  a  separate,  enclosed,  well-ventilated 
fire-proof  room  with  standard  fire  doors  at  all  communicating  openings. 

Note. — The  installation  of  gas  producers  in  cellars,  basements,  or  any  other 
places  where  artificial  light  will  be  necessary  for  their  operation,  is  considered  hazard- 
ous and  will  not  be  permitted  except  by  special  permission  of  the  underwriters  having 
jurisdiction. 

Note. — The  portions  of  these  rules  relating  to  the  design  and  construction  of 
apparatus  are  but  a  partial  outline  of  requirements.  A  producer  which  fulfils  the 
conditions  herein  outlined  and  no  more  will  not  be  necessarily  acceptable.  All  appli- 
ances should  be  submitted  for  examination  and  report  before  being  introduced  for 
use. 

b.  The  smoke  and  vent  pipe  shall,  where  practicable,  be  carried  above  the  roof 
of  the  building  in  which  the  apparatus  is  contained,  and   adjoining   buildings,  and 
when  buildings  are  too  high  to  make  this  practicable,  the  pipe  shall  end  at  least  10 
feet  from  any  wall.     Such  smoke  or  vent  pipes  shall  not  pass  through  floors,  roofs, 
or  partitions,  nor  shall  they,  under  any  circumstances,  be  connected  into  chimneys 
or  flues. 

c.  Platforms  used  in  connection  with  generators  must  be  of  metal.     Metal  cans 
must  be  used  for  ashes. 

d.  The  producer  and  apparatus  connected  therewith  shall  be  safely  set  on  a 
solidly  built  foundation  of  brick,  stone,  or  cement. 

e.  While  the  plant  is  not  in  operation  the  connection  between  the  generator  and 
scrubber  must  be  closed  and  the  connection  between  the  producer  and  vent  pipe 
opened,  so  that  the  products  of  combustion  can  be  carried  into  the  open  air.     This 
must  be  accomplished  by  means  of  a  mechanical  arrangement  which  will  prevent  one 
operation  without  the  other. 

/.  The  producer  must  have  sufficient  mechanical  strength  to  successfully  resist 
all  strains  to  which  it  will  be  subjected  in  practice. 

g.  Wire  gauze  not  larger  than  sixty  mesh  or  its  equivalent  must  be  used  in  the 
test-pipe  outlet  in  the  engine  room. 

h.  If  illuminating  or  other  pressure  gas  is  used  as  an  alternative  supply,  the  con- 
nections must  be  so  arranged  as  to  make  the  mixing  of  the  two  gases  or  the  use  of 
both  at  the  same  time  impossible. 

i.  Before  making  repairs  which  involves  opening  the  gas  passages  to  the  air,  the 
producer  fire  must  be  drawn  and  quenched  and  all  combustible  gas  blown  out  of  the 
apparatus  through  the  vent  pipe. 

j.  The  opening  for  admitting  fuel  shall  be  provided  with  some  charging  device 
so  that  no  considerable  quantity  of  air  can  be  admitted  while  charging. 

k.  The  apparatus  must  have  name  plate  giving  the  name  of  the  device,  capacity, 
and  name  of  maker. 

Gas  Explosions. — Explosions  resulting  from  an  ordinary  explosive  mixture  of 
producer  gas  in  pipes,  holders,  tanks,  or  other  apparatus,  where  said  explosive  mix- 


90 


GAS   PRODUCERS 


ture  is  ignited  without  previous  compression,  the  resulting  explosive  force  exerted 
does  not,  in  the  experience  of  the  writer,  exert  a  maximum  pressure  of  over  60  Ibs. 
per  sq.in.  It  is  therefore  manifest  that  any  connections,  fittings,  etc.,  which  may 
be  subject  to  such  explosives,  should  have  a  safe  working  pressure  or  rupturing  point 
above  this  figure. 

One  serious  explosion  in  the  experience  of  the  writer  in  connection  with  the  gas 
producer  power  plant  having  a  holder  occurred  as  follows: 

The  fire  bed  of  producer  having  been  permitted  to  become  porous,  the  exhauster 
drew  through  the  producer,  and  forcing  into  the  holder  a  certain  portion  of  un- 


The  Vajen  Helmet.  Cut-out  Section  of  Vajen  Helmet. 

FIG.  63. — For  Working  in  Asphyxiating  Atmosphere. 

decomposed  air,  thus  forming  an  explosive  mixture  in  the  holder.  As  a  matter  of 
fact,  prior  to  this  the  gas  supplied  the  engine  was  so  inferior,  due  to  the  condition 
of  the  fire  bed,  which  contained  a  high  percentage  of  CO2,  producing  a  very  slow 
combustion  in  the  engine  cylinder,  that  a  portion  of  the  charge  "  hung  over." 

This  condition  of  affairs  caused  the  engine  to  back-fire,  or  fire  on  the  admission 
stroke,  thereby  igniting  the  explosive  mixture. 

This  could,  of  course,  occur  in  installations  without  a  holder,  but  of  course 
there  would  not  be  the  accumulated  volume  of  gas.  It  is  possible  that  its  liability 
might  be  reduced  to  a  minimum  by  the  insertion  within  the  pipe  lines  of  proper  wire 
screens  between  the  engine  and  holder. 


WORKS    DETAILS 


91 


Gas  Asphyxiation. — According  to  Dr.  Haldane  air  containing  so  small  a  per- 
centage as  0.2%  of  carbon  monoxide,  should  be  regarded  as  entailing  risk  to  life. 
The  chief  danger  of  carbon  monoxide  lies  in  its  lack  of  odor  unless  combined  with 
sulphurous  or  other  odorous  compound. 

First  aid  in  cases  of  poisoning  lies  in  the  application  of  heat,  artificial  respira- 
tion, and  stimulants.  Muscular  action  should  be  as  limited  as  possible. 

The  action  of  carbon  monoxide  as  a  poison  consists  in  its  combination  with  the 
hemoglobin  of  the  blood,  which  causes  the  corpuscle  to  become  inert  and  prevents 
its  combination  or  rather  revivification  through  union  with  oxygen. 

The  illustrations  show  the  Yajen  patent  helmet  for  use  in  gaseous  atmosphere, 
in  which,  by  reason  of  the  fact  that  it  can  be  put  on  in  three  seconds  and  taken  off 
in  two,  is  a  particularly  effective  apparatus  for  rescue  work,  repairing  gas  leaks,  etc. 
The  air  supply  is  sufficient  for  at  least  one  hours'  service.  The  reservoir  may  be 
re-charged  within  two  minutes  and  will  stand  for  months  ready  for  service,  the  gauge 
indicating  the  amount  of  air  which  it  contains. 

Oxygen  Administration. — Artificial  respiration  by  oxygen  should  be  adminis- 
tered preferably  before  natural  respiration  has  entirely  ceased,  or  after  some  slight 
respiration  has  been  started  by  placing  the  patient  in  a  sitting  position,  lifting  the 


WHEEL  WRENCH 
.YOKE 

THUMB  SCREW 


FIG.  64. — Oxygen  Administration  Apparatus. 

arms  above  the  head  and  moving  them  down  to  the  sides  thereby  inflating  and 
deflating  the  chest,  by  blowing  in  the  patient's  mouth,  or  by  the  use  of  brandv  or 
other  restoratives. 

Care  should  be  taken  that  the  tongue  of  the  patient  has  not  been  swallowed  or 
contracted  into  the  thorax,  in  which  case  it  should  be  withdrawn  with  forceps  and 
held  as  nearly  as  possible  in  normal  condition.  It  may  be  remembered  that  good 
oxygen  gas  is  harmless  and  the  lungs  may  be  completely  filled  without  danger  to  the 
patient.  The  administration  of  oxygen  may  be  performed  in  company  with  the 


92  GAS   PRODUCERS 

ordinary  means  of  resuscitation,  manipulating  the  limbs  and  chest,  the  mouth-  and 
nose-piece  being  held  either  to  the  nose  or  mouth.  After  partial  resuscitation  the 
patient  may  be  benefited  by  taking  deep  inhalations  of  the  oxygen  from  the  mouth- 
piece. 

The  method  of  applying  oxygen  is  shown  in  the  illustration,  and  the  following 
are  the  directions  to  be  followed:  Remove  paper  seal  from  opening  in  valve,  slip 
yoke  over  so  that  the  tubular  projection  on  same  will  fit  into  opening  of  valve. 
Tighten  thumb  screw.  Fill  bottle  half  full  of  warm  water,  put  cork  in  bottle  firmly, 
then  connect  short  rubber  tube  attached  to  yoke  with  long  glass  tube  in  bottle. 
Turn  the  gas  on  very  slowly  with  small  wheel-wrench.  The  volume  of  oxygen  being 
given  can  be  estimated  by  the  flow  of  bubbles.  Close  the  valve  gently  but  firmly. 

According  to  Dr.  J.  S.  Haldane  effect  of  carbon  monoxide  upon  man  is  as  follows: 

Percentage 

of  Carbon  EFFECT  ON  MEN 

Monoxide. 

0.05  After  half  an  hour  to  two  hours,  giddiness  on  exertion. 

0.1          "        "  "         "  "       inability  to  walk. 

0.2  "       loss  of  consciousness  and  perhaps  death. 

0.4          "       "  "        "          "       probable  death. 

1.0          ' '     a  few  minutes,  loss  of  consciousness,  followed  before  long  by  death. 


DOWN    DRAFT    PRODUCERS 

THE  down-draft  producer  has  as  its  raison-d'etre  the  fixing  of  the  hydrocarbons 
by  their  passage  through  an  incandescent  fire-bed  after  their  formation  instead  of 
passing  off  immediately  in  the  gas,  as  is  the  case  with  the  up-draft  producer. 

Failing  in  this  fixing  action,  the  down-draft  apparatus  would  have  no  cause  for 
existence.  As  a  matter  of  fact,  some  of  its  features  are  positively  objectionable,  as, 
for  instance,  the  double  ash  zones,  with  their  ever-increasing  tendency  to  meet,  also 
percolation  down  through  the  fire-bed  of  the  finer  ash  from  the  upper  zone,  stopping 
the  voids  and  causing  the  back  pressure  so  characteristic  of  this  type  of  apparatus. 
It  must  be  conceded  that  the  down-draft  apparatus  must  essentially  be  of  the  multi- 
unit  type,  for  the  following  reasons:  In  order  to  give  a  longer  time  contact  in  the 
formation  of  the  gas  and  the  fixing  of  the  hydrocarbons.  The  limit  of  fire-bed  oper- 
ation made  practical  by  continued  stoking  is  four  feet,  and  should  this  fire  become 
in  the  slightest  degree  porous  or  honeycombed,  the  time  contact  is  not  sufficient  for 
the  fixing  operation  necessary. 

With  a  multi-unit  arrangement,  however,  a  reversal  in  flow  in  operation  is  possi- 
ble, which  combines  the  advantage  of  presenting  fresh  carbon  surfaces,  stirring  up 
the  ash,  clearing  it  from  the  voids,  breaking  into  the  channels,  equalizing  combustion 
throughout  the  cross-section,  reducing  clinker,  and  gaining  an  all-around  higher  rate 
of  efficiency. 

The  advantage  of  such  operation  has  long  been  admitted  in  water-gas  practice 
where  it  is  usually  customary  to  reverse  the  runs  at  the  ratio  of  two  up  runs  and  one 
down  run. 

Per  contra,  the  disadvantages  of  single-unit  down-draft  apparatus  is  shown  by 
the  fact  that  it  cokes  through  the  center  of  the  producer  with  coking  coals,  or  forms 
an  ash  zone  through  the  center  with  non-coking  coals  (the  former  being  merely  an 
intermediate  stage  of  the  latter),  with  a  result  that  it  is  almost  impossible  to  main- 
tain uniform  conditions. 

Another  difficulty  to  be  met  with  in  down-draft  units  is  the  formation  of  lamp- 
black, especially  around  the  grates.  With  some  fuels  it  has  been  found  necessary 
to  admit  a  small  quantity  of  secondary  air  at  this  point  in  order  to  produce  sufficient 
combustion  to  gasify  this  lampblack.  A  large  portion  of  the  lampblack  is,  however, 
used  in  the  multi-unit  type  of  down-draft  producer  by  re-carburation  of  the  gas  as 
well  as  the  preventing  of  fixing  and  clogging  on  account  of  its  physical  action. 

93 


94  GAS   PRODUCERS 

In  a  multi-unit  down-draft  producer  the  rate  of  flow,  or  rather  the  relative  rate 
of  flow,  per  unit  of  fuel,  is  somewhat  reduced;  hence  to  some  extent  a  corresponding 
reduction  or  wire  drawing  of  the  gases  through  the  fuel  bed  with  attendant  central 
coking  or  ashification  follows. 

It  is  with  an  intention  to  prevent  this  core  burning  that  producers  of  the  Smith 
type  introduce  a  central  tuyere  admitting  the  air  at  the  center  of  the  fuel  bed.  These 
tuyeres,  however,  are  more  or  less  expensive  and  difficult  to  maintain  by  reason  of 
their  water  cooling,  also  the  central  admission  of  the  air  reduces  the  time  contact 
of  its  passage  through  the  fuel,  and  there  is  not  sufficient  firing  surface  in  which  to 
bake  all  of  the  hydrocarbons.  These  are  merely  the  disadvantages  of  an  otherwise 
very  satisfactory  arrangement,  and  noted  merely  by  way  of  general  consideration. 

By  reason  of  the  ash-forming  conditions  herein  discussed,  5  to  6%  of  ash  may 
be  considered  as  a  limit  of  content  in  fuel  used  in  down-draft  apparatus,  and  a  very 
much  smaller  content  should  be  required  as  a  limitation,  where  such  ash  is  strongly 
inclined  to  fuse  or  where  it  fuses  at  a  relatively  low  temperature.  The  maximum 
volatile  content  permissible  is  usually  between  20  and  30%,  some  manufacturers 
limiting  it  to  a  maximum  of  15%. 


THE    WOOD    SYSTEM 

It  is  the  intention  in  this  work,  in  describing  specific  gas  producers,  to  select 
those  which  are  distinctive,  as  representing  certain  types  and  not  in  any  way  to 
prejudice  opinion  in  favor  of  any  particular  make  or  manufacture  of  apparatus. 

The  Taylor  Producer,  more  commonly  known  to  the  gas  industry  by  the  name 
of  the  "Wood  Producer,"  by  reason  of  its  being  manufactured  by  R.  D.  Wood  & 
Co.  of  Philadelphia,  is  an  excellent  example  of  the  simple  type  of  pressure  and  suction 
producer,  and  has  been  especially  successful  in  operation  upon  anthracite  fuel, 
although  they  also  manufacture  producers  to  be  used  with  coke,  lignite,  and  bitu- 
minous coal. 

The  distinctive  feature  of  this  producer  is  a  rotative  ash  table  or  grate,  which 
by  its  rotation  tends  to  stir  the  fire,  or  primarily  to  close  by  the  tort  given  to  the 
fire,  or  fuel  bed,  any  air  chimney  or  lines  of  cleavage  which  may  have  occurred 
throughout  the  fuel  bed. 

This  type  of  producer  is  exceedingly  simple  and  easily  operated.  It  is  run  with 
a  comparatively  shallow  fuel  bed,  and  the  results  obtained  are  best  described  in  the 
experiments  performed  by  the  Fuel  Testing  Section  of  the  United  States  Geological 
Survey  in  St.  Louis  and  published  by  the  latter. 

Directions  for  starting  the  R.  D.  Wood  pressure  producers  are  as  follows:  "  In 
starting  the  producer  a  good  quality  of  ash,  with  little  unburned  material,  should  be 
used  in  filling  up  the  bosh  of  the  producer.  The  ash  should  be  brought  up  to  a 
point  about  6  inches  above  the  blast  hood,  and  should  at  no  time  approach  nearer. 
Neglect  of  this  precaution  may  cause  the  loss  of  the  blast  hood.  At  the  start  small 
pieces  of  clinker  or  broken  material  may  be  placed  about  the  hood  to  keep  the 
material  from  packing  too  tightly  and  obstructing  the  blast.  On  this  bed  a  fire 
is  built  and  a  light  blast  supplied  and  coal  added  until  the  requisite  bed  of  incan- 


PRODUCER   TYPES 


95 


descent  fuel  is  attained.  The  depth  of  the  incandescent  bed  will  depend  on  the  kind 
and  size,  etc.,  of  fuel,  as  elsewhere  indicated.  With  soft  coals  it  will  range  from 
2  feet  to  3  feet  and  with  anthracites  somewhat  less;  with  large  coke  or  anthracite 


FIG.  65. — Taylor  No.  7  Producer  with  Revolving  Bottom. 

perhaps  4  feet  or  more.  It  is  often  better  to  keep  the  fire-bed  approximately  near 
one  level  by  occasional  removal  of  ashes  rather  than  to  allow  the  fuel  bed  to  build 
to  a  great  height  and  then  remove  large  quantities.  This  latter  will  seriously  injure 
the  quality  of  the  gas  and  perhaps  cause  runs  of  the  coal  and  its  loss  in  the  ashes." 


96  GAS   PRODUCERS 

AVERAGE  OF  NUMEROUS  COAL  TESTS  IN  R.  D.  WOOD  PRESSURE  PLANT 


Composition  of  Fuel. 

Bituminous  Coal. 

Lignites. 

Peat 
No.  1. 

Average. 

Max. 

Min. 

Average. 

Max. 

Min. 

Moisture  

6.83 
33.06 
49.8 
10.32 
2.41 

16.69 
42.46 
73.7 
23.44 
7.36 

1.43 
9.70 
31.19 
2.77 
.28 

26.6 
31.4 
32.6 
9.53 
1.29 

39.56 
38.41 
45.69 
15.47 

4.88 

8.51 
25.54 
23.80 
2.74 
.47 

21 
51.72 
22.11 
5.17 
4.45 

Volatile  combustible  ....        .    . 

Fixed  carbon  

Ash  

Sulphur  .         

Composition  of  Gas  by  Volume. 

Carbon  dioxide,  CO2  

9.84 
.04 
.18 
18.28 
12.90 
3.12 
55.60 

23.89 
18.60 

11.93 
2.81 

10.55 
0.16 
.17 
18.72 
13.74 
3.44 
53.22 

25.20 
19.30 

13.90 
9.20 

12.40 
.0 
.4 
21.0 
18.5 
2.20 
45.5 

Oxvffen.  O-,  .  , 

Ethylene,  C2H4  

Carbon  monoxide,  CO  

Hydrogen,  H2  

Methane,  CH4  

Nitrogen,  N2  

B.T.U.  per  cubic  foot  

152.1 

176 

126.6 

158.4 

188.5 

125.5 

175 

B.T.U.  per  Ib.  of  coal  as  fired  .... 

12280 

14674 

8735 

8350 

10685 

6970 

8127 

THE    TAIT    SYSTEM 

This  apparatus  is  for  the  manufacture  of  producer  gas  without  the  use  of  steam 
or  water  vapor.  In  the  operation  of  gas  engines  utilizing  producer  gas  as  a  fuel, 
considerable  trouble  has  been  experienced  from  variation  in  the  gas  and  especially 
from  pre-ignitions  in  the  engine,  and  it  was  with  a  view  to  obviate  these  troubles  that 
a  process  has  recently  been  put  upon  the  market  for  generating  a  gas  from  anthracite 
or  bituminous  fuel  in  the  usual  form  of  producer,  but  containing  no  hydrogen  except 
that  supplied  in  the  fuel  employed. 

The  producer  gas  usually  manufactured  from  anthracite  fuel  will  be  found 
by  volumetric  analysis  to  be  about  as  follows: 


CO2. 
02.  . 
CO.. 
H2.  . 
CHd. 
N., 


Volume  per  cent. 

. ..       4.6 

...       0.5 

. ..     23.8 

...     15.5 

1.1 

54.5 


A  gas  of  this  analysis  will  be  found  to  have  about  139  B.T.U.'s  per  cu.ft.,  and 
is  considered  a  very  good  producer  gas. 

However,  in  practice,  where  a  gas  is  used  for  engine  purposes,  it  is  a  well-known 
fact  that,  due  to  the  changes  in  load  on  the  engine,  the  analysis  does  not  remain  as 
above,  on  account  of  incident  changes  in  the  temperature  of  the  fire,  which  deter- 
mine the  quantity  of  draft  passing  up  through  the  fuel  bed  on  various  engine  loads. 


PRODUCER   TYPES  97 

As  the  amount  of  draft  passing  up  through  the  fuel  bed  determines  the  temper- 
ature of  same,  it  follows  that  the  amount  of  steam  disassociated  in  the  hot  zone  of 
the  fire  will  vary  with  the  load  on  the  engine.  In  other  words,  only  about  10%  of 
the  steam  fed  to  a  producer  will  dissociate  at  1300°  F.  (this  being  approximately 
the  temperature  in  the  fuel  bed  when  the  engine  is  running  light),  while  on  the  other 
hand  when  the  producer  is  running  at  its  full  rated  capacity  the  temperature  in  the 
hot  zone  of  the  fire  will  rise  to  2000°,  at  which  point  practically  complete  dissocia- 
tion of  the  steam  occurs. 

The  effect  of  this  variation  in  the  steam  dissociation  is  shown  in  the  amount  of 
hydrogen  contained  in  the  resultant  gas;  for  example,  analyses  taken  at  low  load 
will  show  from  5  to  8%  hydrogen,  while  other  analyses  taken  at  full  load  will  show 
18%  hydrogen,  or  even  higher. 

Now,  the  effect  of  this  variable  quantity  in  the  active  part  of  the  gas  necessarily 
affects  the  regulation  of  the  engine,  and  this  is  especially  true  when  it  is  remembered 
that  the  rate  of  combustion  in  a  gas  engine  cylinder  of  carbon  monoxide  and  hydrogen 
is  about  as  twro  to  one,  the  hydrogen  being  the  quicker  burning  of  the  two  and  the 
element  for  which  the  ignition  on  the  engine  has  been  set.  The  effect  on  a  gas  engine 
operating  on  producer  gas  under  these  varying  conditions  is  naturally,  therefore, 
subject  to  irregularities  for  the  following  reason: 

We  will  suppose  that  a  plant  rated  at  100  h.p.  is  being  fed  with  a  gas  made  under 
the  usual  process  of  a  steam-blasted  producer.  The  gas  fed  to  the  engine  will,  due 
to  the  variation  of  temperature  at  different  loads,  change  from  125  B.T.U.  to  145, 
or  thereabouts,  and  while  this  variation  in  heat  units  is,  of  course,  a  disadvantage, 
the  throttle  on  the  engine  could  well  take  care  of  same,  provided  that  the  proportion 
of  the  constituents  forming  the  gas  do  not  also  change. 

Unfortunately,  while  at  full  load  the  engine  is  operating  on  a  gas,  the  active 
part  of  which  consists  of  about  30%  hydrogen  (and  the  ignition  of  the  engine  being 
set  so  as  to  coincide  with  this  hydrogen  and  being  too  late  to  derive  the  full  benefit 
from  the  carbon  monoxide),  it  will  be  found  that  when  the  engine  is  running  light 
that  the  drop  in  temperature  will  affect  the  amount  of  hydrogen  to  such  an  extent 
as  to  practically  reduce  the  same  to  a  negligible  quantity.  Now,  under  these  con- 
ditions it  will  be  noted  that  the  ignition  of  the  engine  is  wrong,  being  altogether  too 
late  for  the  carbon  monoxide  which  at  that  time  forms  the  most  important  part  of 
the  gas. 

To  overcome  this  well-known  defect  some  engine  builders  provide  for  an  ignition 
system,  the  timing  of  which  is  controlled  by  the  speed  of  the  governor,  but  even  this 
method,  although  tending  to  help  matters  under  some  conditions,  falls  far  short  of 
being  a  complete  remedy. 

The  natural  way  to  overcome  this  defect  would  be  to  make  changes  in  the  pro- 
ducer, not  the  engine,  which  would  supply  a  gas  having  a  uniform  composition  under 
all  loads,  or  at  least,  if  this  is  impossible,  supplying  a  gas  which  contains  only  one 
active  constituent,  so  as  not  to  affect  the  timing  on  the  engine  under  any  conditions. 
If  this  is  done,  it  will  be  seen  that  the  throttle  on  the  engine  will  take  care  of  the 
variations  in  quality  of  the  gas,  that  is  to  say,  if  at  low  load  the  gas  is  merely  weaker, 
but  containing  the  same  constituents  as  at  full  load,  it  can  readily  be  seen  that  the 
throttle  valve  of  the  engine  will  run  wider  open  under  these  conditions  with  no  result- 


98  GAS  PRODUCERS 

ant  bad  effect  on  the  regulation.  Such  a  gas  can  be  readily  generated  by  supplying 
any  form  of  gas  producer  with  a  draft  consisting  of  air  alone,  and  this  has  often  been 
tried. 

Although  this  method  of  gas  generation  will  supply  a  gas  answering  the  require- 
ments, another  difficulty  is  experienced  due  to  the  fact  that  the  fire  in  the  producer, 
when  fed  with  pure  air,  will  soon  reach  such  a  high  degree  of  temperature  as  to  melt 
the  fusible  ash  in  the  fuel,  thereby  forming  excessive  clinkers,  which  stick  to  the 
lining,  clog  up  the  grates  and  generally  cause  shut-downs. 

Advantages  of  the  Tail  Producer.  —  This  problem  has,  however,  been  overcome 
by  the  Combustion  Utilities  Company  of  New  York,  who  have  patented  a  process 
for  supplying  the  air  draft  to  a  producer  diluted  with  a  certain  amount  of  C02,  this 
CO2  being  obtained  from  any  available  source,  such  as  for  example  the  exhaust  of 
the  engine.  By  admitting  a  fixed  proportion  of  C02  under  the  fuel  bed  in  the  pro- 
ducer, the  percentage  of  free  oxygen  in  the  draft  supplied  to  the  producer  is  cut  down 
to  the  point  where  excessive  temperatures  in  the  producer  are  entirely  prevented, 
while  at  the  same  time  sufficient  temperature  is  obtained  to  cause  a  conversion  of 
the  CO2  formed  in  the  lower  layers  of  the  fire  to  CO  in  the  upper  layers,  and  to  supply 
a  resultant  gas  having  approximately  the  following  analysis: 


CO2              

Volume  per  cent. 
1.8 

O2. 

0.2 

CO       

26.2 

H> 

0.4 

CH4  

1.7 

N.. 

69.7 

This  gas,  while  of  a  very  much  lower  total  heating  value  than  the  gas  formed 
under  the  usual  method  of  producer  operation,  is  found  to  generate  just  as  much 
power  in  a  gas  engine  with  cylinders  of  a  given  size  as  the  usual  type  of  producer  gas, 
while  on  the  other  hand  absolute  freedom  from  pre-ignitions  is  experienced,  due  to 
the  absence  of  hydrogen,  and  from  reasons  explained  above,  such  variations  as  occur 
in  the  amount  of  CO  in  the  gas  (and  these  variations  are  found  to  be  very  slight 
between  no  load  and  full  load),  are  not  such  as  to  affect  the  regulation  of  the  engine 
to  even  a  small  extent. 

Furthermore,  complete  control  of  the  temperature  of  the  fuel  bed  is  maintained 
by  operating  the  valve  supplying  the  C02  to  the  ash  pit.  In  the  illustration  here- 
with is  shown  an  elevation  and  partial  section  of  a  plant  arranged  under  this  process, 
and,  as  will  be  seen,  the  exhaust  pipe  22  by-passes  parts  of  the  exhaust  back  to  the 
producer  through  valve  7,  from  whence  it  goes  to  the  ash  pit.  At  the  same  time 
the  air  supply  enters  with  it  through  the  pipe  and  valve  6  in  a  predetermined  pro- 
portion. 

When  operating  suction  producers  under  this  process,  it  is  usual  to  employ  a 
mechanically  operated  exhauster  (14),  as  shown  in  the  illustration,  the  effect  of  same 
being  to  suck  the  gas  from  the  producer  and  pass  same  into  the  engine  at  an  abso- 
lutely constant  pressure  of  about  two  inches  water.  This  arrangement  is  particularly 


PRODUCER   TYPES 


90 


100 


GAS   PRODUCERS 


advantageous  when  it  is  desired  to  operate  two  or  more  engines  from  a  suction  pro- 
ducer, as  the  gas  supplied  to  the  engine  is  always  under  the  uniform  pressure  and  a 
test  burner,  as  shown  by  the  illustration,  can  be  watched  by  the  operator  to  see  that 
his  gas  is  of  uniform  character. 

The  apparatus  (14)  consists  of  a  positive-type  exhauster  operated  by  motor  or 
other  suitable  means,  and  which  draws  the  gas  from  the  producer  as  indicated  by 
the  arrow  points,  and  discharges  the  same  toward  the  engines  and  at  a  predetermined 
and  absolutely  fixed  pressure. 

This  pressure  regulation  is  very  simply  obtained,  by  the  fact  that  the  outlet  of 
the  exhauster  communicates  through  several  pipes,  to  a  seal  of  water  contained  in  the 
base  of  the  apparatus,  this  seal  of  water  being  set  to  the  desired  point  to  give  best 
results  at  the  engines.  Any  excess  gas  over  and  above  this  pressure  naturally  bub- 
bles up  through  this  water  seal,  returning  to  the  inlet  side  of  the  exhauster.  This 
apparatus  in  a  very  simple  manner  takes  the  place  of  the  usual  gas  holder  and  enables 
engines  to  be  operated  in  parallel  from  the  same  suction  producer. 


FIG.  67. — Automatic  Regulation  Exhauster.     (No.  14  in  Diagram  of  System.) 

This  apparatus  was  found  to  greatly  assist  in  steadying  up  the  conditions  upon 
which  the  plant  operated  and  was  absolutely  necessary  to  close  regulation  when  it 
was  desired  to  operate  more  than  one  engine  from  a  single  suction  producer. 

It  was  found  when  using  this  process  (in  which  the  resultant  gas  contains  no 
hydrogen),  that  very  much  higher  compression  pressures  could  be  handled  with 
safety  in  the  engines  employed,  and  it  is  usual  to  operate  engines  using  this  system 
at  a  compression  pressure  of  200  Ibs.  This,  of  course,  greatly  increases  the  efficiency 
of  the  engine,  while,  at  the  same  time,  it  is  usually  found  that  the  horsepower  will 
run  up  about  10%  beyond  the  point  obtainable  when  running  the  same  engine  on 
regular  producer  gas  containing  hydrogen. 

Numerous  tests  have  been  run  with  this  process  and  have  proven  the  superiority 
of  this  type  of  gas  for  engine  work  over  the  usual  form  of  gas  containing  hydrogen, 
not  only  in  point  of  economy,  but  more  especially  in  regard  to  the  reliability  of  oper- 
ation, the  same  being  on  a  plane  with  a  steam-engine  installation  of  the  same  size. 

One  of  the  features  incidental  to  this  process,  which  proves  attractive  to  many 
using  steam-blasted  producers  of  the  suction  type,  is  the  ability  to  operate  the  pro- 
ducer continuously  without  stopping  the  engine  when  the  fires  are  cleaned,  the  reason 
for  this  being  that  opening  the  ash-pit  doors  for  cleaning  the  producer  has  no  effect 


PRODUCER   TYPES 


101 


on  the  quality  of  the  gas,  as  it  does  under  the  steam-operated  conditions,  for  the 
reason  that  only  air  and  exhaust  gases  are  passing  up  through  the  fuel  bed,  and  the 
steam  which  goes  up  under  ordinary  conditions,  and  which  is  cul  off  by  absence  of 
suction  when  the  ash-pit  doors  are  open,  is  eliminated  at  all  times,  and  conditions 
are  therefore  the  same  running  with  the  ash-pit  doors  open  or  closed,  with  the  excep- 
tion that  to  operate  for  any  long  period  with  the  ash-pit  doors  open  would  cause  an 
overheating  of  the  fuel  bed,  due  to  too  much  oxygen  reaching  the  fire. 


FIG.  68. — View  of  Previous  Illustration. 


Regarding  the  operation  of  a  producer  plant  operating  under  this  system,  the 
services  of  one  fireman  for  each  300  b.p.  in  small  units,  or  for  each  500  h.p.  in  large 
units  will  be  sufficient,  provided  that  means  are  at  hand  for  delivering  the  coal  upon 
the  working  platform,  which,  in  the  case  of  a  producer  is,  as  shown  in  the 
illustration,  at  the  top  of  the  apparatus  in  the  form  of  a  hopper. 

The  cleaning  of  the  fire  requires  slightly  less  work  on  the  part  of  the  operator 
than  the  cleaning  of  the  fires  under  a  steam  boiler  of  the  same  capacity,  while  on 
the  other  hand  the  stoking  with  fresh  coal  and  the  poking  down  of  the  fuel  bed  are 
.about  the  same  as  that  required  on  a  steam-operated  plant.  It  should  be  borne  in 


102 


GAS   PRODUCERS 


mind,  however,  that  a  somewhat  higher  degree  of  intelligence  is  required  from  a 
producer  fireman  than  from  a  boiler  fireman,  as  in  the  one  case  all  he  has  to  do  is 
to  watch  his  steam  gauge  to  tell  what  results  he  is  getting,  and  on  the  other  hand 
he  has  to  know  by  the  color  of  the  flame  issuing  from  his  sample  burner  whether  the 
gas  is  satisfactory,  and  what  to  do  to  make  it  so,  whether  to  put  on  fresh  coal,  or 
poke  down  the  fire.  Any  man  of  ordinary  intelligence,  however,  can  master  the 
running  of  the  producer  in  from  one  to  two  weeks  of  actual  experience,  at  the  end  of 
which  time  he  should  experience  no  trouble  whatever. 

Regarding  the  efficiency  of  a  producer  operating  under  this  arrangement,  this 
has  been  found  to  be  80%,  provided  that  the  down-take  pipe  from  the  producer  is 
surrounded  by  a  pre-heater  jacket,  for  the  purpose  of  returning  to  the  fuel  bed  some 
of  the  sensible  heat  lost  in  the  gas.  While  this  efficiency  is  practically  the  same  as 
that  of  a  producer  operated  on  the  blast  containing  steam,  on  the  other  hand,  the 
efficiency  of  the  gas  produced,  when  burned  in  a  gas  engine,  increases  the  economy 
of  same,  so  that  an  efficiency  of  26%  is  readily  obtained  in  the  ordinary  three-cylinder 


Lost  in  Producer 
885B.T.U.  7.2 


Lost  in  Scrubber 

1270  B.T  U. 

10.4 


.. 

7.6° 

Returned  by 
Exhaust  Gases 


FIG.  69. — Diagram  of  Heat  Distribution  with  Tait  Process. 

vertical  type  of  gas  engine,  where  the  valve  chambers  are  separated  from  the  main 
cylinders,  while  in  engines  in  which  the  valves  open  directly  into  the  cylinder  still 
higher  economies  can  be  shown. 

In  other  words,  the  total  efficiency  of  the  plant  reckoned  from  the  heat  supplied 
in  the  form  of  coal  to  the  power  actually  developed  by  the  engine  will  be  found  to  be 
slightly  over  19%.  This  figure  being  obtained  in  direct  comparison  with  the  same 
producer  operating  with  the  usual  steam  blast  and  with  the  same  engine,  in  which 
case  only  developing  a  total  efficiency  for  the  plant  of  13%,  or,  to  carry  the  compari- 
son still  farther,  as  compared  with  a  non-condensing  steam  plant  of  100  h.p.  (this 
being  the  size  of  the  plant  on  which  the  gas  tests  were  run),  it  will  be  found  that  the 
best  results  obtainable  show  less  than  6%  efficiency  of  the  whole  steam  plant. 

Regarding  the  floor  space,  etc.,  for  a  producer  plant  of  this  character,  this  will 
be  found  to  be  the  same  as  standard  producer  practice,  and  is  based  upon  allowing 
for  a  gasification  with  a  maximum  of  15  Ibs.  anthracite  coal  per  square  foot  of  internal 
diameter  per  hour  in  the  case  of  suction  producers,  and  8  Ibs.  per  sq.ft.  per  internal 


PRODUCER  TYPES 


diameter  in  case  of  pressure  producers.  As  this  is  substantially  the  practice  where 
producers  are  operated  with  steam  blast,  the  point  of  its  capacity  rating  and  avail- 
able space  does  not  enter  into  the  argument. 

The  plant  shown  in  the  accompanying  illustration  has  a  capacity  of  175  h.p., 
and  is  installed  in  a  room  50  X  20  ft.  with  an  overhead  room  of  20  ft.  This  room 
contains,  in  addition  to  the  entire  producer  plant,  two  engine  units  of  125  and  50  h.p. 
respectively,  as  well  as  auxiliary  machinery  for  blasting  the  producer,  air  compressor 
for  starting  engine,  electric  generators,  switchboards,  etc.,  and  compares  very  well 
with  the  necessary  room  required  for  a  steam  installation  of  the  same  capacity. 

When  operating  with  bituminous  fuel,  there  is  additional  apparatus  consisting  of 
a  rotary  tar  separator  which  would  be  driven  from  the  same  motor  which  drives  the 
exhauster;  the  additional  space  for  this  apparatus  would  not  affect  the  layout  suffi- 
ciently to  increase  the  over-all  dimensions  of  the  plant. 


Lost  in  Producer 
885  B.T.U. 


Lost  i:.  Scrubber 
1-220  B.T.U. 
10.4% 


.  Returned  by 
Exhaust  Gases 


FIG.  70. — Another  Example  of  Heat  Distribution. 


A  heat  balance  of  such  a  plant  will  be  found  to  be  about  as  follows,  assuming 
a  coal  of  12,253  B.T.U.  per  cu.ft.,  and  an  average  load  on  the  plant  of  102  h.p.,  for 
a  duration  of  the  test  of  24  hours: 

B.T.U. 

Total  heat  of  combustion  per  pound  of  coal,  by  calorimeter. . . .  12,253 

Coal  consumed  per  hour,  Ibs 106.52 

B.T.U.  supplied  to  plant  per  hour 1,305,214 

Heat  lost  in  scrubber  water  per  hour 145,124 

Heat  lost  in  water  jackets  of  engine  per  hour 342,719 

Water  jacket  manifold  around  exhaust  pipe  per  hour 63,966 

Heat  converted  into  work 267,225 

Heat  lost  in  exhaust  gases,  after  deducting  the  amount  re- 
turned under  the  producer  per  hour 354,802 

Estimated  loss  per  hour  from  radiation  from  producer,  etc.  .  . .  131,378 

Total.  .  .  .   1,305,214 


104  GAS   PRODUCERS 

As  will  be  noted  in  the  foregoing  table,  the  losses  in  the  plant  are  largely  occa- 
sioned by  heat  given  off  in  the  jacket  water  of  the  engine  and  the  temperature  of 
exhaust  gases.  This  entire  amount  can  be  utilized  towards  heating  the  premises, 
as  is  done  in  some  installations,  in  which  case  the  total  efficiency  of  the  plant  is  raised 
to  a  corresponding  degree. 

Operation  of  the  Tait  Producer. — The  temperature  of  a  gas  leaving  the  producer 
under  the  Tait  System,  is  about  800°  F.  The  temperature  of  the  air  and  exhaust 
gases  entering  under  fuel  bed  will  approximate  or  average  500°  F.  The  latter  tem- 
perature will,  of  course,  vary  largely  with  the  equipment  and  general  conditions, 
especially  the  distance  of  the  exhaust  muffler  from  the  inlet  of  the  producer. 
Usually  the  exhaust  gases  from  the  engine  will  leave  the  manifold  of  the  engine  at 
about  845°  F.,  this  being  slightly  lower  than  the  temperature  found  in  operating 
under  engines  under  the  standard  or  steam  producer  gas  system. 

The  amount  of  C02  appearing  in  the  primary  air  of  the  producer  and  reflecting 
the  acidulation  of  this  air  by  the  use  of  flue  or  exhaust  gas,  will  vary  from  one-half 
to  four  and  a  half  per  cent,  the  minimum  and  maximum  extremes  reflecting  the 
ratio  between  the  load-factor  and  total  capacity  of  the  producer,  a  higher  rate  of 
gasification  per  square  foot  of  grt  te  surface  in  the  producer,  requiring  a  larger  amount 
of  the  endothermic  agent. 

As  a  check  upon  the  gas  when  the  plant  is  in  operation,  the  writer  taps  the  line 
somewhere  between  the  purifier  and  the  engine,  testing  same  for  CO  and  CO2  only, 
for  practical  purposes;  it  is  only  necessary  to  test  for  CO2  once  the  plant  has  been 
put  in  satisfactory  operation,  for  if  the  Orsat  shows  not  over  2%  C02  in  the  finished 
gas,  everything  else  can  be  assumed  to  be  correct,  for  the  reason  that  any  drop  in 
temperature  in  the  producer  below  the  dissociated  point  in  CO2  would  show  a  high 
volume  of  CO2  in  gas  fed  the  engine;  whereas,  if  the  fire  goes  to  the  other  extreme 
and  becomes  too  hot,  CO2  in  disproportionate  amount  will  again  show  in  the  analy- 
sis, indicating  blow-holes  in  the  fire,  etc. 

Which  of  these  two  conditions  cause  the  CO2  in  the  gas  can  be  readily  noted  by 
observing  whether  the  producer  appears  hot  or  cold  on  the  outside.  If  it  appears 
quite  hot  and  the  CO2  in  the  analysis  shows  too  high,  the  fire  is  getting  into  a  burned- 
out  condition  and  requires  poking  down  and  fresh  coal;  if,  on  the  other  hand,  the 
outside  of  producer  is  almost  cold  and  the  CO2  in  the  gas  is  abnormally  high,  it  shows 
that  the  temperature  of  the  fire  has  fallen  below  the  right  point,  and  all  that  is 
necessary  to  do  in  this  case  is  to  close  off  the  exhaust  where  it  enters  the  ash  pit,  so 
that  the  fire  may  feed  on  fresh  air  alone;  this  will  bring  up  the  temperature  of  the 
fuel  bed  rapidly  until  the  same  has  reached  the  right  point.  Analysis  of  the  gas 
during  this  time  will  show  a  drop  off  of  CO2  until  it  gets  down  to  about  2%,  where 
it  belonged. 

The  usual  method  of  keeping  track  of  the  operation  of  the  producer  is  to  watch 
the  flame  issuing  from  the  testing  burner.  When  the  gas  is  weak  from  any  cause 
whatever,  or  in  other  words,  when  it  is  high  in  CO2,  the  flame  will  assume  a  yellowish 
color,  and  will  have  a  tendency  to  blow  out,  while,  on  the  other  hand,  when  every- 
thing is  running  as  it  should,  the  flame  will  burn  steadily  with  a  strong  blue  color. 
Any  man  who  has  operated  one  of  these  producers  for  a  week  or  ten  days  can  easily 
learn  from  practice  what  to  do  by  watching  this  flame.  As  to  the  variation  of  qual- 


PRODUCER  TYPES  105 

ity  of  gas  fed  to  the  engine,  this  will  not  be  found  to  vary  over  5%  while  the  engine 
is  in  operation,  and  the  variation,  as  it  is  only  in  quantity  of  CO  and  not  in  quality 
(as  in  the  case  of  regular  producer  gas  containing  two  active  constituents  and  where 
the  proportion  of  constituents  to  each  other  varies,  due  to  the  variation  of  load), 
will  not  affect  the  operation  of  the  engine,  as  the  throttle  governor  will  take  care  of 
any  variations,  that  is  to  say,  the  throttle  will  run  further  open  when  the  gas  is 
"weak"  and  close  up  more  when  it  becomes  rich  again. 

Other  things  being  equal  and  the  coal  of  a  fairly  good  grade  and  not  inclined 
too  much  to  clinkering,  it  is  well  to  run  the  producer  at  a  high  temperature,  so  that 
the  dissociation  zone,  which  is  the  bottom  12  ins.  of  the  fire,  shall  be  about  2000°  F. 

As  regards  the  admission  of  air  to  the  producer,  there  is  no  necessity  of  regu- 
lating this,  it  only  being  necessary  to  regulate  the  amount  of  exhaust,  as  the  one 
will  affect  the  other  inversely;  it  being  understood  that  the  more  exhaust  passed 
through  the  producer  the  lower  the  temperature  of  the  fire  in  the  producer  and  vice 
versa,  this  being  entirely  under  the  control  of  the  operator,  and  being  an  advantage 
not  obtained  with  other  systems. 

Starting  Up. — To  start  plant,  build  fire  in  producer  (1)  of  wood  or  charcoal, 
leaving  purge  pipe  open,  so  as  to  cause  a  natural  draft.  When  the  kindling  is  thor- 
oughly ignited,  dump  in  sufficient  coal  through  hopper  (2)  to  gradually  build  up  a 
bed  of  fuel,  continually  increasing  the  depth  of  fuel  until  same  has  reached  the  bot- 
tom of  the  magazine. 

The  fire  is  now  in  condition  to  be  left  over  night  with  purge  pipe  open  and  one 
of  the  ash-pit  doors  open  about  one  inch,  which  will  allow  sufficient  draft  to  circulate 
through  the  producer  to  ignite  the  whole  mass  of  coal  during  the  night. 

In  the  morning  see  that  there  are  at  least  two  inches  of  water  in  the  seal  by-pass 
pot  (9),  as  shown  by  water  column  on  side  of  same.  Open  the  vent  pipe  (8)  on  top 
of  this  pot,  then  open  by-pass  valve  (16);  start  up  exhauster  (14).  The  attendant 
should  then  close  the  purge-pipe  valve  on  pipe  at  producer  and  also  open  valve  in  pipe 
leading  from  producer  to  scrubber. 

As  soon  as  this  is  done  the  exhauster  (14)  will  produce  a  sucking  action  of  the 
bed  of  the  producer,  discharging  the  gas,  etc.,  up  through  the  vent  pipe  (15). 

A  few  minutes  after  starting  the  blower  try  the  gas  at  the  burner  (17),  and  if 
it  burns  with  a  steady  blue  flame  the  engine  may  be  started. 

In  starting  the  engine  it  is  well  to  see  that  the  vent-pipe  valve  (8)  is  wide  open, 
likewise  the  by-pass  valve  (16)  around  at  the  blower.  After  the  engine  has  been 
started  the  vent-pipe  valve  (8)  should  be  closed  and  the  by-pass  valve  (16)  regulated 
so  as  to  produce  a  pressure  on  water  gauge  of  about  two  inches.  The  wrater  gauge 
should  show  a  suction  of  about  three  inches  or  less  when  the  plant  is  running  under 
full  load. 

When  a  marked  decrease  of  load  is  put  on  the  engine  the  valve  (16)  may  be 
further  closed,  so  as  to  keep  up  the  pressure  as  shown  at  gauge. 

When  shutting  down  the  plant  all  that  is  necessary  is  to  cut  off  the  gas  where 
it  enters  the  engine  valve  (21),  and  to  open  the  vent-pipe  valve  (16),  so  that  the  gas 
handled  by  the  blower  may  escape  through  pipe  (15). 

This  is  the  procedure  for  shut-downs  of  a  few  minutes,  but  should  it  be  desirable 
to  stop  the  plant  for  several  hours,  such  as  over  night,  proceed  as  above,  and  then 


106  GAS   PRODUCERS 

stop  blower,  close  valve  between  producer  and  scrubber,  and  open  valve  at  the  bot- 
tom of  purge  pipe;  then  the  air  inlet  of  the  producer  may  be  partially  closed,  so  as  to 
just  admit  sufficient  air  to  keep  the  fuel  in  good  condition  over  night. 

Troubles. — Explosions  in  the  muffler  boxes  and  exhaust  pipe  are  usually  occa- 
sioned by  MIS-FIRING  of  the  engine,  and  this  "mis-firing"  is  almost  invariably  caused 
by  ignition  trouble,  the  igniters  in  one  cylinder  failing  to  work  and  the  gas  igniting 
in  the  exhaust  pipe  of  muffle  by  the  next  charge  when  it  leaves  the  engine.  There  is 
no  particular  damage  caused  by  this  trouble  beyond  the  loss  of  power  which  it  entails, 
and  the  knowledge  from  the  noise  of  the  exhaust. 

The  remedy  is  to  locate  the  igniter  which  is  giving  the  trouble  and  to  stop  the 
engine  and  change  the  igniter.  For  this  purpose  it  is  always  necessary  to  have  a 
duplicate  set  of  igniters  handy  for  changing.  It  is  well  to  mention  here  that  engineers 
should  always  on  taking  igniters  out  of  their  engines  clean  and  test  same  immediately 
before  doing  anything  else,  so  that  when  they  are  again  called  upon  for  an  igniter 
they  can  always  have  a  supply  ready  and  in  condition  to  operate.  Much  trouble  is 
occasioned  by  engineers  taking  out  old  igniters  and  laying  them  aside  and  forgetting 
to  clean  them,  with  the  result  that  when  another  igniter  is  needed  suddenly  there 
is  none  available. 

Back  Firing. — Another  trouble  which  may  be  encountered  is  back  firing.  This 
is  usually  distinguished  by  flame  coming  out  through  the  inlet-air  pipe  (20),  or  in 
cases  where  this  inlet  pipe  comes  from  the  outside  of  the  building  and  cannot  be 
seen,  it  will  be  noted  that  the  back  firing  by  producing  a  back  pressure  on  gas  main 
(18)  will  splash  the  water  in  the  water  seals  around  the  apparatus  as  it  fires  back 
towards  the  producer.  Back  firing  is  usually  occasioned  by  an  improper  mixture 
at  the  engine  or  by  a  sudden  weakening  of  the  gas,  and  should  never  occur  if  the  pro- 
ducer operator  has  his  fire  in  good  condition;  for,  long  before  the  engine  gives  trouble, 
the  pilot  flame  (17)  which  should  be  kept  burning  all  the  time  will  get  very  low  or  blow 
out  altogether  on  account  of  weak  gas. 

The  remedy  for  this  trouble  is  to  poke  down  the  fire,  as  a  blow  hole  through  the 
fuel  bed  is  probably  the  cause  of  the  trouble.  A  small  amount  of  coal  should  also  be 
added  to  help  matters  and  the  trouble  should  not  last  more  than  two  or  three  min- 
utes with  proper  handling.  Changing  the  mixture  of  air  and  gas  at  valves  will  also 
help  temporarily.  If  back  firing  occurs  when  the  gas  is  burning  steadily  with  a  good 
flame  at  testing  burner  (17),  it  will  usually  be  found  that  one  of  the  inlet  valves  on 
the  engine  is  either  "pitted,"  or  does  not  close  properly,  due  to  the  foreign  matter  on 
the  valve  seat.  This  can  be  taken  care  of  when  the  engine  is  shut  down  after  the  day's 
run,  it  being  unnecessary  to  shut  down  on  this  account,  providing  that  the  engine  will  run. 

Pre-ignitions. — This  trouble  consists  of  explosions  inside  the  cylinders  of  an 
engine  when  both  the  inlet  and  exhaust  valves  are  closed,  but  occurring  too  early  in 
the  working  cycle,  with  the  result  that  an  impulse  is  given  to  the  combustion  in  the 
reverse  way  to  that  in  which  the  engine  is  operated. 

Pre-ignitions  are  almost  invariably  due  to  particles  of  carbon  or  other  foreign 
matter  in  the  cylinder  becoming  heated  redhot,  and  thereby  igniting  the  charge 
prematurely.  They  may  also  occur  from  the  timer  on  the  engine  being  shifted  to  too 
early  a  period.  This  is  easily  remedied  by  shifting  the  timer  back  again.  In  the 
case  of  prematures,  which  are  traced  to  foreign  substances  in  the  cylinder,  the  only 
remedy  is  to  shut  down  and  clean  out  the  affected  cylinder. 


PRODUCER   TYPES  107 

The  engine  attendant  should  always  watch  his  exhaust  gases  where  they  emerge 
from  the  building  to  see  that  they  are  perfectly  clean,  any  smoke  in  the  exhaust  gas 
indicating  a  too  lavish  expenditure  of  cylinder  oil,  or  an  improper  mixture  of  the 
fuel,  air,  and  gas,  either  of  which  will  be  apt  to  cause  a  deposit  of  carbon  in  the  gas 
engine  cylinders  and  to  result  in  the  pre-ignitions  already  referred  to. 

When  shutting  down  an  engine  used  for  power  purposes  the  gas  valve  should 
always  be  shut  off  before  cutting  off  the  ignition  circuit,  thereby  insuring  the  fact 
that  there  is  no  live  gas  left  in  the  engine  cylinders.  The  reason  for  this  precaution 
is  to  obviate  danger  to  attendants,  who,  when  turning  the  engine  over  to  its  center 
when  getting  ready  to  start  again  might  encounter  a  "kick"  from  an  unexploded 
charge  in  one  of  the  cylinders  with  disastrous  results.  By  leaving  the  igniters  on 
until  the  engine  actually  stops,  every  particle  of  combustible  gas  in  the  cylinders  is 
exploded,  and  it  is  therefore  harmless. 

In  operating  the  producer  (1),  it  is  always  well  to  remember  that  a  deep  bed  of 
fuel  insures  steady  operating  conditions,  and  further,  that  systematic  poking  every 
hour  and  a  half  or  thereabouts,  according  to  the  amount  of  load  on  the  plant,  will 
keep  the  fuel  bed  properly  packed  down,  prevent  clinkers  adhering  to  the  lining  of  the 
producers  and  also  obviate  the  risk  of  blow-holes  burning  up  through  the  fire. 

The  Combustion  Utilities  Company's  process  comprises  a  method  of  controlling 
the  temperature  of  the  fire  by  the  admission  of  exhaust  gases  under  the  fuel  bed,  and 
while  the  valves  (7)  and  (6)  on  each  plant  are  set  by  the  erecting  engineer  at  their 
approximate  running  positions  before  the  plant  is  turned  over  to  the  cutomers,  the 
operator  has  always  under  his  control  these  valves  by  which  he  can  cool  down  his 
fire  when  it  becomes  too  hot,  due  to  overload;  or,  on  the  other  hand,  if  when  start- 
ing up  he  wishes  to  heat  his  fire  up  quickly  he  can  do  so  by  keeping  valve  (7)  tightly 
closed,  and  valve  (6)  wide  open,  thereby  admitting  pure  air  to  the  producer  until  such 
time  as  the  fuel  bed  attains  the  desired  temperature. 

The  operator  should  at  all  times  see  that  the  water  gauges  on  the  various  parts 
of  the  apparatus  are  in  working  order,  and  that  there  is  no  great  discrepancy  between 
the  reading  of  any  two  adjacent  gauges,  as  such  discrepancy  would  be  due  to  a 
clogging  of  the  apparatus  with  foreign  substances,  such  as  dirt  or  ashes,  which  would 
interfere  with  the  running  of  the  plant  if  not  removed. 

As  long  as  the  gas  issuing  from  the  testing  burner  (17)  burns  with  a  steady  blue 
flame,  the  engine  should  run  with  complete  saitsfaction,  and  any  troubles  encountered 
under  these  conditions  are  surely  traceable  to  the  engine,  and  should  be  looked  for  in 
that  quarter.  If,  however,  the  flame  flickers  and  goes  out  there  is  trouble  in  the  pro- 
ducer which  should  be  attended  to  immediately  to  avoid  having  trouble  with  the 
engine. 

AVERAGE  COMPOSITION  OF  ORDINARY  PRODUCER  GAS 

Per  Cent. 

Carbonic  acid,  C()2 5.8 

Oxygen,  O2 1.3 

Carbonic  oxide,  CO 19.8 

Hydrogen,  HL> 15. 1 

Marsh  "as,  CH4 1.3 

Nitrogen,  X 56.7 

B.T.U.  gross  per  cu.ft 136 


108 


GAS   PRODUCERS 


AVERAGE  COMPOSITION  OF  TAIT  PRODUCER  GAS 

Main  Gas  Supply  to  Engine:  Percent 

Carbonic  acid,  C02 2.2 

Oxygen,  02 1.3 

Carbonic  oxide,  CO 25.6 

B.T.U.  gross  per  cu.ft 103 . 7 

Mixture  of  Air  and  Engine  Exhaust  Gases  Entering  Producer: 

Carbonic  acid,  C02 3.3 

Oxygen,  O2 18.9 

Carbonic  oxide,  CO 0.1 

Complete  Analysis: 

Carbonic  acid,  CO2 1.8 

Oxygen,  O2 1.2 

Carbonic  oxide,  CO 26 . 2 

Hydrogen,  H2 0.4 

Marsh  gas,  CH4 0.7 

Nitrogen,  N 69 . 7 


Total.  .  ,100.0 


GAS  ANALYSIS  MADE  DURING  TEST  OF  TAIT  PRODUCER  SYSTEM 

(No  Steam  Used.) 


B.T.U. 

by 
Calorimeter. 


110 
105 
109 
110 
101 
105 


Time. 


12  Noon 
1.45  P.M. 
3.30  P.M. 
5.45  P.M. 
3.45A.M. 
6.30A.M. 


CO2 


2.0 

2.0 

1.75 

1.70 

1.70 

1.75 


O2. 


1.3 
1.2 
1.2 
1.1 
1.2 
1.3 


CO. 


26.9 

25.0 

25.85 

26.3 

25.9 

26.95 


H2. 


0.3 
0.2 
0.4 
0.8 
0.6 
0.2 


CH< 


0.5 
0.6 
0.8 
1.0 
0.6 
0.5 


N. 


09.0 
71.0 
70.0 
69.1 
70.0 
69.3 


LOOMIS-PETTIBONE  SYSTEM 

Process. — The  method  of  operating  the  Loomis-Pettibone  gas-generating  appa- 
ratus is  readily  understood  by  following  the  course  of  the  air  and  gas  currents  shown 
by  the  accompanying  cuts.  Air  is  drawn  down  through  the  incandescent  fuel  beds 
in  the  generators  by  the  positive  exhauster  and  the  usual  chemical  action  takes  place, 
the  oxygen  in  the  air  combining  with  the  carbon  in  the  fuel  to  form  C02.  As  this 
gas  passes  further  down  through  the  fuel  bed  it  combines  with  more  carbon,  viz.: 
C02+C=2CO.  Any  water  in  the  fuel  is  decomposed  by  the  incandescent  carbon 
liberating  the  hydrogen,  and  the  oxygen  combining  with  the  carbon  forms  C02,  and 


PRODUCER  TYPES 


109 


PH 
.2 

c 
J 


110 


GAS    PRODUCERS 


PRODUCER   TYPES  111 

CO.  The  other  constituents  of  the  gas  are  derived  from  the  volatile  portions  of  the 
fuel.  The  resulting  producer  or  blast  gas  passes  from  the  bottoms  of  the  generators 
through  the  connecting  pipes  and  into  the  waste-heat  boiler.  In  passing  up  through 
the  tubes  of  this  boiler  a  large  percentage  of  the  sensible  heat  is  absorbed  by  the 
water  forming  steam.  The  gas  then  passes  from  the  boiler  to  the  bottom  of  the  wet 
scrubber  where  it  comes  in  contact  with  the  water  by  passing  under  a  diaphragm 
plate.  In  ascending  through  the  scrubber  it  is  divided  by  the  scrubbing  material 
and  meeting  counter  streams  of  water,  is  cooled,  and  at  the  same  time  the  greater 
portion  of  the  impurities  are  removed.  Thence  it  passes  through  the  exhauster  to 
the  dry  scrubber  where  the  remaining  dust,  etc.,  is  removed.  It  then  passes  on  to 
the  mixed-gas  holder.  At  intervals  runs  of  water  gas  made  by  turning  steam  into 
the  bottom  of  one  generator.  The  steam  in  passing  through  the  incandescent  fuel 
bed  is  decomposed,  the  hydrogen  being  liberated  and  the  oxygen  combining  with  the 
carbon  to  form  C02,  CO,  etc.  This  gas  passes  from  the  first  generator  across  to  the 
second,  down  through  it  and  then  takes  the  same  course  as  the  producer  gas  through 
the  rest  of  the  apparatus.  The  steam  is  only  applied  for  about  a  minute  when  the 
manufacture  of  producer  gas  is  resumed.  The  water  gas  in  passing  up  through  the 
first  fire  carries  with  it  some  of  the  volatiles  of  the  fuel  which,  in  passing  down  through 
the  second  generator,  are  converted  into  fixed  gases  and  the  second  fuel  bed  also 
serves  to  decompose  any  steam  which  may  have  passed  intact  through  the  first  fire. 
Coal  is  fed  into  the  generators  through  the  charging  doors  provided  in  the  crowns 
of  the  machines  and  the  tops  of  the  fires  being  plainly  visible  can  be  deposited  to  the 
best  advantage. 

Apparatus. — The  apparatus  consists  of  two  cylindrical  shells  lined  with  fire-brick 
and  having  fire-brick  grates.  Charging  doors  with  sliding  covers  are  attached  to  the 
top  plates  of  the  generators  and  suitable  brick-lined  cleaning  doors  are  bolted  to  the 
sides  of  the  generator  to  give  access  when  cleaning  above  and  below  the  grates.  A 
brick-lined  pipe  joins  the  generators,  being  located  near  the  top  of  the  shells.  Brick- 
lined  pipes  connect  the  ash  pits  of  the  generator  with  the  lower  gas  chamber  of  the 
waste-heat  boiler.  Steam  connections  are  provided  for  introducing  steam  into  the 
top  or  bottom  of  the  generators.  The  boiler  is  of  the  vertical  cylindrical  multitubular 
fire  tube,  and  the  lower  gas  chamber  is  brick-lined.  Manholes  both  in  the  upper  and 
lower  gas  chambers  provide  openings  for  inspection  and  cleaning.  Water-cooled 
valves  are  placed  in  the  connections  between  the  generators  and  boiler.  A  valve  is 
located  at  the  gas  outlet  on  the  boiler  and  cast-iron  pipe  connects  the  boiler  with 
the  scrubber.  The  scrubber  is  a  cylindrical  steel  shell  in  the  lower  portion  of  which 
is  placed  a  diaphragm  plate  just  above  the  water  level.  This  forces  the  gas  to  come 
in  contact  with  the  water  in  the  bottom  of  the  scrubber.  Suitable  overflows  for 
waste  water  are  provided.  The  interior  of  the  shell  is  divided  into  sections  by  trays 
supporting  the  scrubbing  material.  The  upper  portion  of  the  scrubber  is  enlarged  to 
contain  excelsior  or  other  suitable  material.  The  water  is  introduced  below  the 
second  tray  from  the  top  and  the  one  directly  below  it.  The  gas  main  then  connects 
the  top  of  the  scrubber  with  the  exhauster  which  is  of  the  positive  type  and  is  either 
driven  by  a  motor,  steam  engine,  or  other  motive  power.  A  by-pass  is  arranged  around 
the  exhauster  to  provide  means  of  releasing  the  vacuum  on  the  apparatus  while  mak- 
ing a  water  gas  run,  and  beyond  the  exhauster  are  the  controlling  valves  for  directing 


112  GAS   PRODUCERS 

the  gas  either  into  purge  stack  of  holder.  The  purge  stack  is  only  used  when  blasting 
up  the  fires  after  a  stand-by  in  order  to  obtain  the  proper  temperature  in  the  fuel  beds. 
From  the  exhauster  the  gas  passes  through  the  dry  scrubber,  which  is  a  cylindrical 
steel  shell  arranged  with  trays  for  supporting  the  scrubbing  material.  Suitable  man- 
holes for  cleaning  and  charging  are  provided.  The  gas  then  passes  into  the  holder 
which  is  of  the  usual  type. 

Operation. — The  operation  of  the  apparatus  can  be  readily  followed  by  referring 
to  the  accompanying  illustration. 

Fuel  is  charged  into  the  two  generators  to  a  depth  of  about  five  feet  and  after  the 
exhauster  has  been  started  is  kindled  from  above  through  the  doors.  When  it  is 
seen  that  the  fires  have  been  thoroughly  kindled  a  small  quantity  of  steam  is  ad- 
mitted, and  mingling  with  the  air  which  enters  through  the  top  doors,  and  is  drawn  down 
through  the  incandescent  fuel  beds  by  the  action  of  the  exhauster.  The  producer 
gas  thus  generated  passes  down  through  the  grates  of  the  generators,  both  valves 
being  open,  up  through  the  boiler  valve  and  on  to  the  scrubber  and  exhauster.  When 
the  gas  burns  at  the  test  flame  by  the  exhauster,  and  valves  direct  the  gas  through 
the  dry  scrubber  into  the  holder,  the  operator  charges  coal  through  the  open  charg- 
ing doors  as  it  is  needed  and  he  also  regulates  the  quantity  of  gas  made  to  meet  the 
demands  by  altering  the  speed  of  the  exhauster.  The  fires  are  kept  in  a  uniform 
condition  by  making  runs  of  water  gas,  which  is  accomplished  by  closing  the  charging 
doors,  and  introducing  steam.  This  process  is  alternated  by  using  the  valves  above 
and  the  steam  inlets  below. 

If  more  water  gas  is  required  for  metallurgical  work  the  plant  is  arranged  with 
a  separate  water-gas  outlet,  so  that  it  can  be  divided  from  the  producer  gas  and 
stored  in  its  own  holder.  The  intervals  between  cleaning  of  the  fires  is  governed  by 
several  factors,  viz.,  hours  of  operation  per  day,  load  factor,  quality  of  fuel,  etc., 
but  it  is  customary  to  remove  the  ashes  and  clinkers  once  every  three  to  seven  days. 

The  total  efficiency  of  the  apparatus  is  shown  by  the  following  heat  balance: 

PRODUCER  HEAT  BALANCE 

B.T.U.  Per  Cent. 

Total  heat  in  fuel  supplied  to  plant 100,000,000  100.00 

Heat  in  gas  at  60°  F 84,700,000  84. 70 

Heat  removed  by  scrubber  water 8,160,000  8. 16 

Heat  removed  by  water-cooled  valves  ...       1,560,000  1.56 

Heat  lost  by  radiation  and  other  losses  .  .       5,580,000  5.58 

The  points  claimed  for  this  apparatus  meriting  special  attention  are  as  follows: 

1.  It  produces  a  fixed  clean  gas  of  uniform  quality. 

2.  All  varieties  of  fuel  can  be  used  without  any  modification  in  the  construc- 
tion of  the  apparatus. 

3.  Very  high  efficiency  over  wide  ranges  in  load. 

4.  Large  overload  capacity. 

5.  The  ability  to  operate  under  sudden  fluctuations  in  load. 

6.  Stand-by  loss  reduced  to  a  minimum  as  combustion  is  arrested  during  such 
periods. 


PRODUCER   TYPES 


113 


7.  The  fires  being  at  all  times  visible  to  the  operator,  the  fuel  can  be  charged 
to  the  best  advantage. 

8.  The  fires  can  be  kindled  and  plant  be  in  full  operation  in  fifteen  minutes. 

9.  A  fuel  gas  of  high  heating  value  and  low  cost  is  produced. 

10.  Freedom  from  smoke  or  smell,  due  to  apparatus  operating  under  a  vacuum. 

11.  No  tar  extractors  required. 

12.  Ability  to  construct  single  units  of  large  capacity. 

13.  The  use  of  an  exhauster  and  holder  ensure  a  uniform  pressure  on  the  gas 
mains. 

14.  Where  water  is  scarce  or  expensive  the  greater  part  of  the  scrubbing  water  is 
recovered  and  cooled  by  means  of  a  cooling  tower  so  that  the  water  requirements 
for  a  power  plant  are  far  less  than  those  for  a  boiler  plant. 

The  thermal  value  of  the  gas  varies  slightly  according  to  the  conditions  under 
which  the  apparatus  is  operated,  and  also  differs  with  the  fuel  used.  If  a  plant  is 
installed  the  primary  object  of  which  is  to  generate  a  large  proportion  of  water  gas 
for  metallurgical  or  other  purposes,  the  producer  gas  will  have  a  lower  B.T.U.  value 
than  if  the  gas  is  to  be  used  exclusively  for  engine  or  lower  heating  work.  The  fol- 
lowing analyses  are  typical  of  the  above: 

LOOMIS-PETTIBONE  PRODUCER  GAS  ANALYSES 


No. 

I. 

II. 

III. 

IV. 

V. 

VI. 

VII. 

Carbon  dioxide,  CO2  
Oxygen,  O  

3.6 
0.2 

6.0 
0  3 

15.96 
0.11 

21.3 
0.26 

10.7 
0.5 

3.6 
0.2 

5.0 
0  4 

Illuminants  

0.2 

0.28 

0.46 

Carbon  monoxide,  CO.  .  . 

26  9 

38  7 

13  27 

9  86 

17  2 

26  1 

18  6 

Methane,  CH4  

1  1 

3  4 

2  61 

3  45 

3  1 

1  0 

1  2 

Hydrogen,  H  

9.4 

46.4 

20  97 

54.14 

14.0 

9  1 

9  3 

Nitrogen,  N.  . 

58  8 

5  0 

46  80 

10  53 

54  5 

60  0 

65  5 

B.T.U.  per  cu.ft.  at  60°  F.  . 

129.1 

315.0 

140.22 

246.88 

132.7 

125.2 

101.5 

I.  Mixed  gas  using  bituminous  coal. 

II.  Water  gas  using  bituminous  coal. 

III.  Mixed  gas  using  wood. 

IV.  Water  gas  using  wood. 
V.  Mixed  gas  using  lignite. 

VI.  Producer  gas  using  bituminous  coal  (for  gas  engines). 

VII.  Producer  gas  using  bituminous  coal  (producer  gas  practically  a  by-product  from  manufacture  of  water  gas). 

When  operating  to  obtain  the  greatest  yield  of  water  gas  the  ratio  of  water  gas 
to  producer  gas  is  about  1  to  3;  this  proportion,  however,  can  be  increased  to  almost 
any  amount.  The  amount  of  water  and  producer  gas  derived  from  a  ton  of  coal  is 
influenced  by  the  quality  of  coal,  a  poor  grade  of  bituminous  coal  yielding  about 
35,000  to  38,000  cu.ft.,  whereas  a  good  quality  will  produce  as  high  as  50,000  to 
55,000  cu.ft.  '  When  operating  the  plant  to  obtain  a  good  quality  of  mixed  gas,  say 
for  engine  use,  from  160,000  to  200,000  cu.ft.  per  ton  can  be  reasonably  expected. 

The  tar  distilled  from  bituminous  and  lignite  fuel  in  this  apparatus  and  con- 
verted into  a  fixed  gas  is  assumed  to  represent  15  to  20%  of  the  total  calorific  value 
of  the  fuel.  The  fuel  bed  maintained  should  approximate  at  all  times  about  4  ft.  in 
depth. 


114 


GAS   PRODUCERS 


In  the  Loomis-Pettibone  apparatus,  compressed  gas  is  used  for  stoking,  a  charge 
of  some  90  Ibs.  pressure  being  admitted  through  a  quick-opening  valve  (approximat- 
ing H  ins.).  These  "shots"  are  administered  at  intervals  of  30  minutes  and  tend 
to  lift  the  entire  fuel  bed,  which  replaces  itself  and  compacts  with  a  tendency  to 
break  up  any  chimneys  or  honeycombing. 

The  best  results  or  high  efficiency  of  gas  obtained  from  this  process  for  power 
purposes  is  found  with  the  gas  approximating  105  B.T.U.  in  value,  this  usually  repre- 
senting about  5%  of  water  gas  to  95%  of  producer  gas  in  the  total  mixture.  This 
is  probably  by  reason  of  the  fact  that  a  higher  heat  value  is  reflected  by  the  presence 
of  a  large  hydrogen  factor. 

No  difference  in  rating  or  great  surface  capacity  is  made  in  these  producers  for 
anthracite,  wood,  bituminous,  or  coke,  the  discrepancy  in  the  heat  value  off.  these 
fuels  being  compensated  by  their  rate  of  gasification.  All  of  this  apparatus  is  rated 
on  the  basis  of  an  estimated  six-hour  50%  overload. 

The  apparatus  is  built  in  sizes  as  given  below,  the  dimensions  stated  being  the 
diameter  and  height  of  the  generator  shells.  For  convenience  the  various  sizes  are 
rated  at  so  many  horsepower,  which  is  their  normal  capacity,  but  the  overload  out- 
put for  an  hour  or  two  is  50%  higher. 


H.P.  of  plant 250  375 

Diameter  of  generator.     5'3"  6.0" 

Height  of  shell 12'0"          13'0" 


500 

7'0" 

14'0" 


750 
8'0" 
14'0" 


1000 

9'0" 

15'0" 


1500 
lO'O" 
IG'O" 


2000 
ll'O" 

18'0" 


The  floor  space  and  size  of  building  required  to  house  the  above  plants  is  shown 
by  the  following  figures: 


FIG.  73. — Space  occupied  by  Plant. 


Single  Unit  Plants. 


Horsepower 
of  Plant. 

Size  of  both 
Generators. 

A. 

B. 

D. 

Horsepower 
of  Plant. 

B. 

C. 

D. 

250 

5'  3"X12' 

24'  0' 

28'  3' 

28'  0" 

500 

28'  3' 

44'  6" 

28'  0" 

375 

6'X13' 

25'  4' 

31'  0' 

28'  0" 

750 

31'  0' 

46'  6" 

28'  0" 

500 

7'X14' 

26'  4' 

38'  0' 

33'  0" 

1000 

38'  0' 

51'  6" 

33'  0" 

750 

8'X14' 

28'  6' 

40'  10" 

33'  0" 

1500 

40'  10" 

55'  0" 

33'  0" 

1000 

9'X15' 

31'  10" 

42'  3' 

33'  0" 

2000 

42'  3' 

sa'  10" 

33'  0" 

1500 

10'X16' 

36'  0' 

47'  7' 

33'  0" 

3000 

47'  7' 

64'  0" 

33'  0" 

2000 

11'XIS' 

38'  0' 

46'  0' 

33'  0" 

4000 

46'  0' 

72'  0" 

33'  0" 

Double  Unit  Plants. 


In  the  above  table  the  double-unit  plants  consist  of  two  pair  of  generators  with 
their  boilers  and  scrubbers. 


PRODUCER   TYPES  115 

The  only  purification  the  gas  is  given  for  general  use  is  the  washing  it  receives 
in  the  wet  scrubber,  and  the  final  cleaning  is  accomplished  in  the  dry  scrubber.  The 
lower  sections  of  the  wet  scrubber  are  usually  filled  with  coke  or  stones  and  the  upper 
sections,  above  the  water,  with  excelsior.  The  dry  scrubbing  material  usually  con- 
sists of  excelsior  or  sawdust. 

In  special  cases  where  it  is  necessary  to  remove  the  sulphur  from  the  water  gas 
it  is  accomplished  by  resorting  to  the  conventional  type  of  purifying  boxes  filled  with 
iron  oxide  or  lime. 

Uses. — This  system  of  gas  manufacture  is  in  extensive  use  at  the  present  time, 
water  gas  being  utilized  in  a  large  number  of  manufacturing  plants  for  processes 
where  high  temperatures  are  required,  while  the  mixed  and  producer  gases  have  proved 
their  worth  as  fuel  for  lower  heat  work  and  gas  engines.  As  .water  gas  contains  such 
a  large  percentage  of  hydrogen  and  carbon  monoxide,  its  flame  temperature  is  even 
higher  than  natural  gas.  Water  gas  has  a  high  rate  of  combustion,  resulting  in  its 
successful  application  to  direct-fired  furnaces  with  a  minimum  of  combustion  space, 
which  contrasts  strongly  with  oil-fired  furnaces  where  considerable  additional  space 
must  be  provided  to  permit  of  the  full  development  of  the  flame.  It  is  unnecessary 
to  use  regenerative  or  recuperative  furnaces  to  obtain  the  high  temperatures,  but  by 
utilizing  the  waste  heat  in  pre-heating  the  air  used  for  combustion  considerable  econ- 
omies are  effected.  Among  the  processes  in  which  water  gas  is  used  are: 

Small  direct-fired  furnaces  for  welding  and  drop  forging. 

Brass  melting  in  crucibles. 

Steel  melting  in  crucibles. 

Semi-regenerative  pipe-welding  furnaces. 

Soldering  irons  and  furnaces. 

Blow  pipes  for  brazing. 

Tempering  watch  springs. 

Singeing  cloth. 

Japanning  ovens. 

Hardening  and  tempering. 

Annealing. 

Mixed  gas.  which  consists  of  water  gas  and  producer  gas  in  any  desired  propor- 
tion, is  utilized  for  lower  temperature  work  where  regenerative  fire-brick  checkerwork 
is  not  required,  but  with  this  feature  added  to  furnaces,  melting  of  various  metals 
is  readily  accomplished.  The  work  being  done  with  this  gas  consists  of 

Hardening  and  tempering  saws. 
Annealing  and  japanning. 
Pipe-bending  furnaces. 
( Jas  engines. 

Producer  gas  is  also  used  for  the  above  work  in  case  there  is  a  surplus  of  it. 

By  the  use  of  gas  in  furnaces  a  considerable  saving  can  be  effected,  due  to  the 
centralization  of  the  coal  pile  which  obviates  the  necessity  of  carting  or  wheeling  the 
fuel  through  the  shops.  Another  advantage  is  that  there  is  no  interruption  in  the 


116 


GAS   PRODUCERS 


output  of  the  furnaces,  as  is  the  case  where  the  fuel  bed  in  a  coal  or  coke-fired  forge 
has  to  be  replenished,  with  a  consequent  delay  while  the  fresh  fuel  is  kindling;  neither 
is  any  time  lost  in  taking  out  ashes  or  clinker.  This  naturally  results  in  an  increase 
in  the  output  per  man,  which  in  many  cases  is  of  far  greater  monetary  value  than 
any  saving  which  may  be  effected  in  the  fuel.  As  no  space  has  to  be  allowed  for  the 


FIG.  74. — Staub   Suction  Gas  Producer.     Typical    anthracite  suction  producer,  as  manufactured  by 
the  Power  and  Mining  Machinery  Company. 


storage  of  a  fuel  supply  around  each  furnace,  the  available  floor  space  in  a  shop  is 
either  materially  augmented  or  else  in  planning  a  new  building  the  dimensions  of 
the  building  can  be  reduced.  Cleanliness  is  another  good  feature,  dust  from  ashes, 
etc.,  being  eliminated.  Uniform  temperature  can  be  maintained,  which  in  many 
manufacturing  processes  is  a  vital  point.  The  wear  and  tear  on  such  furnaces  is 
reduced,  and  by  using  recuperators  for  pre-heating  the  air,  heat  which  would  other- 
wise be  lost  up  the  stack  is  returned  to  the  furnace. 


PRODUCER  TYPES 


117 


THE   MORGAN   PRODUCER 

The  Morgan  producer,  manufactured  by  the  Morgan  Company  of  Worcester, 
Mass.,  is  perhaps  the  leading  type  of  industrial  producer  manufacturing  producer 
gas  for  metallurgical  and  industrial  work.  The  producer  is  steam  blown  and  is  ex- 
ceedingly simple  and  substantial  in  its  construction. 


FIG.  75. — The  Morgan  Continuous  Gas  Producer  with  George  Automatic  Feed. 

For  its  smoking  it  depends,  in  opposition  to  the  Wood  producer  previously 
described,  more  upon  its  method  of  feeding  the  fuel  than  upon  any  agitation  of  the 
fuel  bed  itself,  the  producer  being  of  the  water-seal  type  and  the  ashes  being  with- 
drawn through  the  seal  or  lute. 

The  George  feed,  with  which  the  Morgan  producer  is  equipped,  when  supplied 
with  a  proper  and  uniform  size  of  fuel,  gives  perhaps  the  most  even  and  complete 


118  GAS   PRODUCERS 

distribution  of  its  charge  over  the  surface  of  the  fuel  bed  which  has  as  yet  been 
obtained.  This  uniformity  of  charge  tends  to  close  any  chimneys  or  lines  of  cleavage 
in  the  fuel  bed  upon  the  top,  instead  of  closing  such  lines  through  the  tort  produced 
in  a  revolving  grate  or  ash  table. 

It  may  be  said  that  the  Morgan  producer  with  its  George  feed,  stops  up  or  covers 
its  chimneys,  where  the  Wood  producer  endeavors  to  close  them.  Again,  with  the 
uniformity  of  feed  attained  with  this  producer,  such  chimneys  or  lines  of  cleavage 
are  less  apt  to  occur,  very  seldom  in  fact  wrhere  a  fair  uniformity  of  fuel  is  used. 

The  Morgan  producer  is  used  entirely  for  metallurgical  or  industrial  work,  and 
is  not  used  for  power;  by  reason  of  the  heat  of  its  gases  and  from  their  direct  appli- 
cation, a  very  high  efficiency  is  claimed  for  the  producer. 


The  Westinghouse  Machine  Company  -has  developed  a  double  zone  bituminous 
gas  producer  in  compliance  with  a  pre-determined  standard  which  involves  a  pro- 
ducer design  capable  of  (1)  continuous  operation,  (2)  producing  a  gas  free  from 
tar,  (3)  operating  at  such  temperatures  as  would  avoid  troublesome  clinker  forma- 
tion, (4)  producing  a  gas  of  normal  constituents  suited  to  high  engine  compression, 
and  (5)  finally  a  producer  that  could  be  readily  operated  by  a  single  attendant  with 
comparatively  little  labor  and  skill.  This  latter  qualification  evidently  necessitates 
a  plant  of  considerable  simplicity. 

This  apparatus  is  running  successfully  upon  both  high  and  low  grades  fuel,  the 
latter  including  the  lignites  of  northern  Colorado,  Texas,  and  South  America.  It 
is  also  satisfactorily  operated  upon  garbage,  crude  meadow  peat,  and  other  waste 
materials.  The  general  scheme  is  indicated  in  a  sectional  drawing  showing  a  com- 
plete plant  with  all  auxiliaries.  An  upper  shell  (A)  superimposed  upon  lower  shell 
(B)  with  cast-iron  evaporator  (E)  between,  a  hollow  air-cooled  top  (C),  commu- 
nicates with  the  evaporator  through  downcomer  (D^  and  uptake  (D2).  A  third 
downcomer  connects  evaporator  with  lower  tuyere  (T).  The  producer  is  supported 
from  four  concrete  foundation  piers  on  a  cast-iron  mantle  ring  (M),  the  lower  rim 
of  which  dips  beneath  the  level  of  the  water  in  the  ash  pit,  forming  a  water  seal. 

In  the  operation  of  this  producer,  green  fuel  is  fed  through  the  open  top  (F), 
and  during  its  descent  to  the  offtake  zone  (0)  is  completely  transformed  into  coke. 
During  its  further  descent  to  the  ash  line  (*S),  this  coke  is  completely  gasified  to 
ash.  There  are,  therefore,  two  independent  fuel  beds,  (A)  and  (5).  In  the  former 
tar  vapors  distilled  from  the  fresh  coal,  are  transformed  into  fixed  gas  which  mixes 
with  the  straight  coke  gas  generated  in  the  lower  zone  (/?). 

Vaporizer. — There  are  two  combustion  zones  in  this  producer,  one  at  the 
extreme  top  and  one  at  the  bottom  just  above  the  tuyere.  This  is  brought  about 
by  a  double  supply  of  vapor  laden  air.  This  air  supply  is  drawn  in  from  above  at 
((r)  (see  plan).  Circulating  entirely  around  the  hollow  top,  it  is  heated  sufficiently 
to  increase  its  capacity  for  taking  up  moistures,  when  it  is  again  circulated  over  the 
surface  of  the  water  in  the  evaporator  (E).  This  vaporizer  is  practically  in  con- 
tact with  the  hot  fuel  bed  at  the  center  of  the  producer,  when  it  generates  the 


119 


proper  amount  of  vapor  to  carry  out  the  endothermic  reactions,  for  cooling  the  fuel 
bed  through  H20  dissociation.  This  evidently  does  away  with  the  necessity  of  an 
external  boiler  to  supply  steam  to  the  producer,  and,  in  general,  conforms  to  the 
practice  of  suction  producer  design  in  large  sizes.  Entering  the  vaporizer  at  £"2, 
heated  air  divides,  emerging  at  E3,  part  ascending  and  part  descending.  Valves 


FIG.  76. — A  175  H.P.  Westinghouse  Double  Zone  Bituminous  Gas  Producer. 


«/i  and  J2  serve  to  control  the  relative  quantity  of  blast  to  the  two  combustion 
zones.  This  relation  constitutes  practically  the  only  variable  in  the  operation  of 
the  plant,  but  for  any  given  fuel,  it  is  only  necessary  to  regulate  these  valves  once. 
The  automatic  proportioning  of  vapor  to  air  is  otherwise  provided  for  in  the  design 
of  the  producer,  so  that  the  process  of  gasification  is  automatic  through  the  entire 
range  of  load. 


120 


GAS   PRODUCERS 


With  variable  fuels,  it  is  important  to  reduce  the  velocity  of  gas  as  low  as 
possible  at  the  offtake.  On  this  account  the  gas  is  drawn  from  the  fuel  bed  at 
several  points  communicating  with  the  annulus  (Ei). 

Rotary  Exhauster. — The  rotary  exhauster  (H)  serves  to  provide  a  positive  and 
uniform  suction  on  the  fuel  bed.  This  type  seems  to  fulfil  the  requirements  and 
incidentally  avoid  the  uncertainties  of  operation  encountered  with  the  hand-regu- 
lated blower.  Thus,  the  plant  becomes  virtually  a  double-zone  suction  type. 

This  exhauster  operates  at  a  constant  speed  and  delivers  gas  to  the  engine 
always  at  constant  pressure  of  a  few  inches  of  water.  This  regulation  is  accom- 
plished by  means  of  a  butterfly  valve  (K)  and  a  gasometer  (/)  which  arrangement 
by-passes  such  part  of  the  gas  delivered  by  the  blower  as  is  not  required  by  the 
engines,  the  remainder  circulating  through  a  small  mixing  heater  overhead.  In 
this  manner  the  necessity  for  a  variable  speed  exhaust  is  avoided. 


FIG.  77. — Section  of  Westinghouse  Producer. 


Holder. — It  will  also  be  noted  that  a  large  gas  holder  is  not  employed  for 
the  control  of  gas  production  as  regards  quality  and  quantity  or  delivery  pressure, 
thereby  effecting  a  material  economy  in  installation. 

Cleaning. — In  the  absence  of  tar,  the  problem  of  cleaning  the  gas  suitably  for 
engine  use,  resolves  itself  into  the  simple  removal  of  dust  and  lampblack.  This  is 
accomplished  by  a  static  cellular  type  washer  (.V)  in  which  the  gas  streams  are 
spread  out  in  a  thin  layer  and  constrained  to  pass  over  the  surface  of  still  water, 
during  which  process  the  foreign  matter  is  thrown  down.  This  reduces  the  quality 
of  foreign  matter  to  about  0.02  of  a  grain  per  cubic  foot,  which  affords  a  very  large 
margin  of  safety  in  actual  operation. 

Water  Seals. — At  (0)  is  a  single-seated  stack  valve  and  at  (P)  a  water  seal 
controlled  by  plug  (Q)  which  is  normally  left  open.  When  the  plant  is  shut  down, 
the  closing  of  valve  (Q)  floods  the  water  seal  (P),  thus  shutting  off  the  rest  of  the 


PRODUCER  TYPES 


121 


plant  and  automatically  opens  the  stack  valve  (0).  This  water  seal  also  makes  it 
possible  to  work  on  the  auxiliary  while  the  producer  is  at  stand-by. 

In  practice,  a  large  part  of  the  foreign  matter  is  thrown  down  in  the  down- 
comer  (D±)  by  the  action  of  a  water  spray  (R),  this  sediment  passing  freely  to  the 
overflow  without  entering  the  static  washer. 

The  water  seal  of  the  producer  proper  may  be  partially  drained  by  a  rotating 
valve  (U).  In  its  up  position,  this  valve  maintains  a  level  as  shown  by  the  dotted 
line.  When  turned  downward,  the  water  is  drained  2  inches  beneath  the  lower  rim 
of  the  mantle  ring  (M),  consequently  breaking  the  seal,  and  allowing  free  ingress 
of  air  at  all  points.  This  is  effective  in  the  starting  of  a  new  fire  in  which  a  heavy 
draft  is  desirable. 

Draft. — In  operation,  the  pressure  at  the  top  fire  bed  is  slightly  below  atmos- 
phere, so  that  when  the  charging  cover  (F)  is  opened,  there  is  no  tendency  for 
smoke  or  gas  to  reach  the  producer  room.  Thus  it  occurs  that  the  most  important 
part  of  the  fuel  is  alwrays  available  for  inspection  and  can  be  easily  worked  down  in 
full  view.  In  addition,  poke  holes  (V)  are  provided  so  located  that  the  sides  of  both 
the  upper  and  lower  linings  may  readily  be  raked  by  a  poker  bar  and  the  ash  settled 
down  as  in  the  normal  operation  of  a  pressure  type  producer.  This  also  gives  access 
to  the  fire  bed — an  important  feature. 

Labor. — The  labor  requirements  are  comparatively  small,  as  the  bed  requires 
poking  seldom  more  frequently  than  once  per  hour.  Ashes  are  removed  about  once 
in  twenty-four  hours.  Thus  it  occurs  that  with  coal  and  ash  separately  handled, 
one  man  can  operate  at  least  three  of  these  producers  without  difficulty.  Coal  may 
be  charged  at  intervals  of  fifteen  minutes  to  one  hour,  according  to  the  load.  Owing 
to  the  low  temperature  at  which  the  fuel  bed  is  maintained,  the  formation  of  large 
clinker  is  entirely  prevented  and  this  trouble  has  not  been  encountered  in  any  of 
the  tests.  Provision  is  made  for  flushing  out  the  vaporizer  at  intervals  to  prevent 
the  deposit  of  mud  in  case  foul  water  were  used. 

Washer. — The  static  washer  is  practically  indestructible  and  partly  self-clean- 
ing; but  in  any  event,  the  various  sections  are  readily  accessible  by  lifting  off  the 
cover.  In  the  remainder  of  the  plant  there  is  little  opportunity  for  deterioration, 
so  that  as  a  whole  this  type  of  plant  presents  a  number  of  important  advantages 
that  have  not  been  possessed  by  its  predecessors,  built  and  tested  under  similar  conditions. 

Operating  Results. — Several  weeks  run  on  Pittsburg  run-of-mine  at  13,000  B.T.U. 
per  pound,  as  fired,  gave  an  average  consumption  of  1.24  Ibs.  per  b.h.p.  hour  con- 
tinuous operation. 

Nature  of  some  of  the  fuels  which  have  been  successfully  used  with  the  Westing- 
house  producer: 

COMPOSITION" 


Runs 

A. 

B. 

C. 

D. 

E. 

Moisture 

20  05 

16  63 

2  03 

38  10 

34  09 

Volatile  

34.44 

33.78 

34.98 

40.54 

30.03 

Fixed  carbon  ....            .    .        

30  85 

42  22 

56  22 

17.86 

26.32 

Ash  

14  66 

7  37 

6  77 

3.50 

9.56 

B.T.U.  pound  as  fired  

8032 

8599 

13305 

6410 

6950 

122 


GAS   PRODUCERS 


Efficiency. — The  efficiency  of  the  producer  does  not  vary  more  than  10%  from 
full  load  to  no  load  on  the  engine,  and  approximates  77.5%  on  higher  heat  value,  or 
71.5%  on  lower.  Samples  of  ash  taken  from  the  producer  during  the  tests  on  Pitts- 
burg  run-of-mine,  show  for  an  average  of  six  samples  less  than  15%  ash. 

Combustion  Rate. — The  rate  of  firing  varied  from  13  to  22.8  Ibs.  per  square 
foot  of  fuel  bed  area  per  hour  at  the  green  fuel  zone.  This  higher  rate  may  be  main- 
tained indefinitely  without  vitiating  the  gas  from  excessive  oxidation  or  without 
clinker  formation.  The  temperature  of  the  gas  leaving  the  fuel  bed  averages  about 
900°  F.,  low  enough  to  prevent  clinker.  With  considerably  hotter  gas,  the  heat 
value  of  the  gas  falls  slightly.  This  temperature,  therefore,  serves  as  a  fair  index 
of  limits  in  regard  to  fuel  bed  temperature. 

Heat  Value. — The  average  samples  of  gas  taken  from  the  engine  show  a  heat 
value  of  about  115  B.T.U.  A  considerably  higher  value  could  be  obtained  by  using 
more  vapor. 

Foreign  Matter. — The  average  gas  samples  show  from  0.015  to  0.025  grain  of 
solid  matter  per  cubic  foot  of  standard  gas.  During  a  week's  test  on  the  auxiliary 
plant,  twenty-five  determinations  showed  a  range  of  solid  matter  from  0.006  to 
0.043.  This  solid  matter  consists  entirely  of  dust  and  a  little  lampblack,  the  heavier 
matter  having  already  been  removed  at  the  discharge  nozzle  of  the  producer  by  a 
water  spray.  These  figures  show  ample  capacity  of  the  cleaning  plant  to  take  care 
of  bituminous  fuels. 


THE   HERRICK   PRODUCER 

In  opposition  to  the  producers  before  described,  the  essential  feature  of  the 
Herrick  producer  is  the  idea  of  disseminating  the  air  from  the  bottom  through  the 
sides  and  top  of  its  patented  tuyere. 

A  claim  made  for  this  producer  is  that  the  air  is  disseminated  so  generally  as 

to  prevent  its  concentration  at  any 
one  point  with  the  attendant  forma- 
tion of  chimneys,  fissures,  or  chan- 
nels. 

This  producer  is  being  extensively 
used  on  bituminous  coals  and  lignite. 
It  is  well  adapted  for  industrial  work 
and  particularly  the  operation  of 
ceramic  and  metallurgical  furnaces. 


FIG.  78.— The  Herruk  Generator  in  Half  Section.          FIG.  79.— Tuyere  and  Steam  Blower  of  Fig.  75. 


PRODUCER  TYPES  123 


SMITH    LIGNITE    PRODUCER 

In  addition  to  the  bituminous  producers  made  by  the  Smith  Gas  Producer  Co., 
they  have  been  particularly  successful  in  manufacturing  a  producer  adaptable  to 
the  use  of  lignite  and  low-grade  fuels. 

It  is  a  fact  that  it  is  almost  impossible  to  operate  the  average  down-draft  pro- 
ducer of  ordinary  construction  on  lignite  coal,  on  account  of  the  fact  that  these  coals 
crumble  to  very  small  dimensions  after  being  heated,  the  crumbling  occurring  at  a 
certain  temperature  and  the  dissociation  being  very  rapid  and  complete,  with  the 
resultant  effect  that  a  sudden  dampering  occurs  due  to  the  instant  accumulation  of 
a  heavy  ash  bed.  As  a  result  the  central  part  of  the  fuel  bed  becomes  very  com- 
pact, so  that  the  fuel  is  driven  to  the  lining  and  channeling  and  high  drafts 
occur. 

In  the  Smith  lignite  producer  this  tendency  is  overcome  by  confining  the  blast 
to  the  producer  to  a  centrally  located  tuyere,  which  delivers  into  the  heart  of  the 
fuel  charged,  so  that  in  whatever  direction  the  blast  may  pass  it  is  obliged  to  go 
through  a  sufficient  depth  of  fuel  to  insure  the  production  of  a  good  gas.  In  this 
way  the  tendency  to  channeling  and  the  driving  of  the  blast  to  the  lining  is  entirely 
overcome. 

This  construction  also  permits  of  the  running  with  a  very  shallow  fuel  bed  which, 
when  used  together  with  a  shaking  grate,  avoids  the  difficulty  with  a  backing  fire 
which  invariably  follows  the  use  of  lignite  fuel. 

Another  feature  of  the  producer  is  the  handling  of  the  ash  which  necessarily 
forms  most  rapidly  and  in  greatest  quantity  at  the  point  closest  to  the  air  inlet  or 
outlet  of  the  tuyere.  In  the  down-draft  producer  this  is,  of  course,  on  top  of  the 
fuel,  and  the  presence  of  this  large  percentage  of  ash  in  the  upper  part  of  the  fuel  bed 
has  been  one  of  the  chief  difficulties  in  operating  this  type  of  apparatus. 

It  is  obviously  impossible  to  work  this  ash  through  the  grate  in  the  ordinary 
way,  since  if  the  ash  is  allowed  to  accumulate  until  it  settles  on  the  grate  the  whole 
fuel  bed  would  consist  of  ash,  and  hence  the  producer  be  out  of  commission.  If  an 
attempt  is  made  to  force  the  ash  down  through  the  fuel  below,  there  must  necessarily 
result  a  great  loss  of  carbon  or  good  coal  from  the  ash  pit  which  will  be  entrained  in 
its  passage,  and  consequent  reduction  in  the  efficiency  of  the  apparatus. 

This  difficulty  has  been  avoided  in  the  Smith  producer  by  arranging  to  deliver 
the  ash  towards  the  center  of  the  fuel  bed  or  that  portion  which  is  directly  under  the 
air  blast  or  tuyere,  where  the  temperature  of  combustion  is  necessarily  the  highest. 
At  this  point  the  ash  is  fused  in  a  large  solid  mass  or  clinker,  which  generally  increases 
in  size  by  accretions  to  its  outside  surface  until  it  becomes  of  sufficient  dimensions 
to  be  easily  detected  in  a  fire,  and  of  sufficient  hardness  to  permit  the  proper  hand- 
ling when  it  is  withdrawn  from  the  fire  from  above  by  means  of  proper  tools  and 
removed  through  the  ash  inlet  pipe  or  tuyere,  from  wrhence  it  is  taken  out  of  the  top 
of  the  producer. 

In  practice  this  process  of  handling  the  ash  is  found  to  be  in  the  highest  degree 
practical.  The  clinker  can  be  withdrawn  at  any  time  when  the  producer  is  in  oper- 


124 


GAS   PRODUCERS 


ation  without  interfering  with  the  production  of  gas,  and  the  ash  taken  from  the 
producer  in  this  way  contains  an  extremely  small  percentage  of  good  fuel  or 
carbon. 

There  is,  of  course,  a  certain  small  amount  of  finely  divided-"  ash  which  is  con- 


Detail  of  Charging  Hopper. 


Section  of  Producer.  Detail  of  Hanging  Grate. 

FIG.  80. — Smith  Lignite  Producer. 


stantly  forming  in  the  lower  part  of  the  fuel  bed  as  a  result  of  the  decomposition  of 
C02  to  CO  by  carbon  in  this  part  of  the  fire.  This  fine  ash  or  dust  is  removed  from 
the  grate  by  simply  shaking  the  grate  from  side  to  side,  thus  agitating  the  fuel  bed 
and  tending  to  close  up  rivers  or  channels,  when  the  down-draft  of  gas  sweeps  the 
fine  ash  from  the  grate  into  the  ash  pit.  In  this  way  the  ash  is  readily  handled 


PRODUCER   TYPES 


125 


without  undue  loss  of  carbon  and  a  packing  of  the  fuel  bed,  consequent  from  the 
use  of  lignite,  entirely  obviated.  Moreover,  the  percentage  of  tar  and  lampblack  in 
the  gas  is  reduced  to  a  minimum  and  the  hydrocarbons  volatilized  to  the  benefit  of 
the  resultant  gas. 


FIG.  81. — Air  and  Steam  Pre-heater. 


In  the  Smith  apparatus  the  fuel  magazine  extends  around  the  air-inlet  tuyere 
and  up  to  the  top  end  of  this  tube.  This  part  of  the  producer  is  now  filled  with  green 
coal.  The  large  diameter  of  this  tube  serves  to  equalize  the  pressure  between  the 
top  of  the  producer  and  the  end  of  the  tuyere,  and  the  fuel  in  the  magazine  becomes 
ignited  from  below,  burning  upward  solely  by  natural  draft,  and  distils  off  the  vola- 


126  GAS   PRODUCERS 

tile  hydrocarbons  which  pass  into  the  upper  part  of  the  producer.  Here  they  become 
slightly  cooled  and  descend  again  through  openings  provided  in  the  top  of  the  central 
draft  tube  where  they  are  mixed  with  air  and  actually  burned  as  soon  as  they  come 
in  contact  with  the  ignited  fuel  at  the  bottom  end  of  the  tuyere. 

When  burned  these  hydrocarbons  become  COa  and  H^O.  These  in  turn  are 
decomposed  when  passing  through  the  coke  in  the  lower  part  of  the  fuel  bed  and 
become  CO  and  H,  their  endothermic  action  being  used  to  moderate  the  temperature 
in  the  middle  of  the  fire. 

The  illustration  herewith  shown  of  the  steam-regulating  device  of  the  Smith 
gas  producer  has  proved  very  superior.  The  balance  valve  or  piston  is  regulated  by 
the  static  head  or  amount  of  suction  created  by  the  incoming  primary  air  to  the  pro- 
ducer, the  amount  of  water  admitted  to  the  vaporizer  being  proportional  to  the 
volume  of  said  air. 

The  passage  of  the  air  and  water  through  the  coils  (B)  of  the  recuperator  tends 
to  make  a  thorough  mixture  of  all  hydrate  or  air  in  a  very  complete  manner.  The 
heat  used  for  the  vaporization  of  the  water,  and  to  some  extent  the  incoming  air,  is 
supplied  by  the  exhaust  gas  of  the  engine. 

It  is,  howrever,  likely  that  an  arrangement  could  be  made  to  abstract  the  sensi- 
ble temperature  of  the  effluent  gases  on  their  passage  through  the  producer  to  the 
scrubber,  should  the  arrangement  as  shown  be  in  any  way  inconvenient. 


LIGNITE  SUCTION  PRODUCERS 

Lignite  suction  producers,  under  the  design  of  the  Gas  Power  Manufacturing 
Co.,  resemble  in  principle  and  general  outline  the  standard  type  of  suction  producer 
for  anthracite  coal,  coke,  and  charcoal.  There  are,'  however,  certain  radical  princi- 
ples in  the  design  made  necessary  by  the  specific  conditions  existing  in  the  gasification 
of  lignitic  fuels,  more  particularly,  by  reason  of  the  larger  percentage  of  moisture, 
volatile  hydrocarbons,  ash  which  they  contain,  the  physical  structure  of  the  lignitic 
fuel,  temperature  at  which  it  disintegrates,  and  on  account  of  extreme  rapidity  of 
the  gasification  or  combination  of  elements.  The  lignite  producer  plant  consists  of: 
producer,  scrubber,  gas  washer,  and  purifier.  Taking  up  these  parts  in  order  seriatum, 
they  may  be  described  as  follows: 

The  Producer. — The  producer  consists  of  a  cylindrical  steel  shell,  with  fire- 
brick lining,  and  has  a  plain  bar  grate,  with  ample  cleaning  doors  and  ash  pit.  Coal 
is  charged  in  the  top  of  the  producers,  through  a  double  closure,  or  feeding  hopper, 
and  may  be  delivered  to  the  hopper  either  by  hand,  from  a  coal  hopper  by  gravity, 
or  through  the  medium  of  a  conveyor. 

No  vaporizer  is  necessary  to  produce  steam  for  the  purpose  of  regulating  the 
temperature  within  the  producer,  inasmuch  as  lignite  coals  usually  contain  a  high 
percentage  of  moisture,  the  evaporation  of  which  within  the  producer  is  sufficient, 
under  most  conditions,  for  all  tempering  purposes.  Where,  however,  this  amount 
is  inadequate  and  must  be  supplemented,  a  small  amount  of  water  is  carried  in  the 
ash  pit,  which  will  evaporate  as  high  as  J  Ib.  of  water  per  Ib.  of  fuel  gasified.  This 


PRODUCER   TYPES 


127 


feature  avoids  perhaps  the  greatest  complication  in  producer  operation,  and  elimi- 
nates the  most  expensive  item  of  maintenance  or  up- keep. 

The  regulation  of  steam,  which  under  ordinary  circumstances  is  a  complex  and 
complicated  process,  requiring  great  skill  on  the  part  of  the  operator,  and  by  bad 
adjustment,  produces  an  excess  of  carbon  dioxide,  hydrogen,  clinkering  in  the  fuel, 
etc.  To  a  great  extent  this  is  obviated  in  the  lignite  producer  and  the  evils  aforesaid 
reduced  to  a  minimum,  the  operation  of  the  apparatus  being  simplified  to  the  most 
primitive  form. 

The  producer  works  up-draft,  the  gases  passing  from  the  top  of  the  producer  to 


FiG.  82. — Lignite  Suction  Producer. 


the  scrubber  in  such  a  way  as  to  penetrate  the  incoming  charge  of  coal,  or  the  "green 
coal"  as  it  is  known,  which  charge  is  pre-heated  by  the  absorption  of  the  sensible 
heat  from  the  effluent  gases,  affording  a  high  degree  of  heat  recuperation,  amount- 
ing in  some  instances  to  say  20%  of  the  total  heat  of  the  fuel,  and  thereby  conserving 
and  restoring  waste  heat  to  the  producer  in  a  most  efficient  and  economical 
manner. 

The  Scrubber. — The  scrubber  is  a  cylindrical  steel  shell  containing  neither 
coke  nor  checker  work,  as  is  the  ordinary  practice,  but  equipped  instead  with  several 
atomizing  sprayers  of  a  peculiar  device  and  design,  which  fill  the  volume  of  the  tank 


128  GAS   PRODUCERS 

with  water  vapor  at  a  certain  tension,  necessary  for  combination  with  the  impurities 
of  the  crude  gas. 

The  function  of  the  scrubber  is  to  cool  the-  gas  and  condense  the  heavy  hydrocar- 
bons which  are  precipitated,  together  with  a  large  portion  of  the  dust  and  ash  which 
they  entrain,  through  the  change  of  volume  in  condensing,  change  of  pressure  and 
also  through  super-saturation  by  the  water  vapor. 

Gas  Washer. — The  gas  washer  is  of  centrifugal  type,  which  separates  the  tar 
and  dust  from  the  gas  by  placing  the  unpurified  product  in  rapid  rotary  motion,  and 
at  the  same  time  subjecting  it  to  a  change  of  volume  and  pressure  in  the  presence  of 
a  finely  divided  water  spray.  The  impurities  washed  out  of  the  gas  in  both  the 
gas  washer  and  scrubber  are  collected  in  a  waterbox,  from  which  they  are  drained  to 
a  sewer. 

In  case  of  the  use  of  lignite,  gas  washers  of  peculiar  efficiency  are  necessary  to 
abstract  from  the  gas  not  only  \vhat  is  known  as  "tar,"  but  the  other  unfixed  hydro- 
carbons which  impregnate  the  gases  in  a  most  tenacious  manner.  These  constitute 
not  only  the  lighter  tar  and  tarry  vapors,  but  oils  of  the  paraffine  series,  ranging 
from  a  light  yellow  viscous  matter  to  the  heavier  seal  brown  oil  tars,  such  as  are  pro- 
duced from  the  distillation  of  crude  oil. 

The  very  wide  range  of  these  impurities  requires  a  cleaning  apparatus  of  great 
comprehension  and  scope,  and  only  a  machine  especially  designed  for  the  purpose 
can  efficiently  purify  the  gas  for  practical  engine  service.  In  installations  where 
water  is  scarce,  the  centrifugal  pump  is  connected  to  the  gas  washer  to  circulate  the 
wash  water,  only  enough  cold  water  being  added  to  cool  and  condense  the  gas. 

The  power  necessary  to  drive  the  gas  washer  varies  from  2  to  4%  of  the  power 
the  engine  supplies.  This  does  not,  however,  change  the  rating  of  an  engine  or 
plant,  inasmuch  as  the  gas  washer  is  so  designed  as  to  deliver  the  gas  to  the  engine 
under  atmospheric  pressure,  or  when  expedient  at  slight  pressure.  This  relieves  the 
engine  of  its  duty  as  a  suction  pump,  in  which  service  no  gas  engine  made  is  a  par- 
ticularly efficient  apparatus.  Hence,  the  resulting  arrangement  really  increases  the 
engine  rating,  and  consequently  the  total  efficiency  of  the  plant,  the  engine  receiving 
a  full  supply  of  gas  in  its  cylinders  at  each  stroke  and  obviating  all  losses  through 
piston  "slip." 

Purifier. — The  sawdust  purifier  is  advisable  to  reduce  the  amount  of  satura- 
tion or  moisture  mechanically  entrained  in  the  gas  in  its  passage  to  the  engine.  This 
purifier  is  the  ordinary  type  and  contains  wooden  trays  covered  with  a  mixture  of 
sawdust  and  planer  chips,  fine  coke,  corn  cobs,  or  similar  material. 

General  Advantages.— briefly  stated,  the  advantages  of  the  up-draft  lignite 
producer  over  the  down-draft  type  (as  represented  by  the  Loomis-Pettibone  and 
Smith  producers)  are  as  follows: 

a.  The  grate  is  accessible  at  all  times  for  cleaning,  preventing  plugging,  banking, 
and  channeling,  and  involving  a  removal  of  clinker  and  ash  with  the  minimum  loss 
of  fuel,  and  without  slowing  the  engine  or  loss  of  power. 

6.  The  sensible  heat  of  the  gases  is  regenerated  by  the  passage  of  gas  through 
the  incoming  or  green  fuel,  which  fuel  absorbs  the  larger  portion  of  this  heat,  con- 
serving it  and  retaining  it  within  the  producer,  at  the  same  time  pre-heating  fuel 
and  bringing  it  up  a  stage  towards  the  heat  of  combustion  or  gasification.  Moreover, 


PRODUCER  TYPES  129 

this  pre-heating  of  the  fuel  drives  off  a  large  portion  of  the  high  moisture  content 
of  the  lignite,  which  would  otherwise  act  as  a  diluent,  and  both  require  a  large  amount 
of  fuel  consumption  in  its  evaporation,  and  subtend  a  hydrogen  content  in  the  result- 
ant gas,  when  distilled  at  the  higher  temperature  of  the  lower  producer  zones.  Not 
only  is  this  an  advantage  in  driving  off  the  hygroscopic  moisture  in  the  lignite  itself, 
but  also  the  moisture  absorbed  by  lignite  upon  its  exposure  to  wet  or  rain,  under 
which  conditions  its  saturation  is  remarkably  high. 

c.  The  quality  of  the  gas,  therefore,  obtained  is  remarkably  uniform  and  high 
in  heat  value  and  low  in  free  hydrogen,  all  of  which  are  essential  advantages  in  gas 
for  power  purposes  and  the  natural  result  of  the  system  hereinbefore  described. 

d.  This  system  is  peculiarly  free  from  danger  to  the  operator,  as  he  is  at  no  time 
exposed  to  the  unprotected  portions  of  the  producers,  or  in  contact  with  areas  where 
explosive  mixtures  may  be  formed. 

e.  The  fixed  carbon  or  combustible  matter  in  the  fuel  is  more  completely  gas- 
ified than    that  writhin  any  other  commercial  system,  there  being  less  grate  loss   or 
unconsumed  combustible  matter  withdrawn  from  the  producer  in  cleaning  or  along 
with  the  ashes. 

/.  The  apparatus  is  of  much  more  simple  construction,  being  more  easily  operated, 
and  possessing  fewer  variable  conditions,  requiring  no  water-cooled  grates,  less  skill 
in  labor,  no  collecting  tubes,  vaporizers,  or  special  fire  tubes,  and  hence  reducing  the 
expense  of  up-keep,  repairs,  and  maintenance. 

The  advantage  claimed  by  builders  of  the  down-draft  producer  consists  in  the 
fixing  of  a  larger  percentage  of  volatile  hydrocarbon  in  the  gas  (the  breaking  up  of 
tars,  oils,  etc.,  into  permanent  gases)  and  through  this  reduction  of  waste,  the  effect- 
ing of  a  greater  fuel  economy;  or,  in  other  words,  the  creating  of  a  higher  total 
efficiency  in  gasification.  It  is  unquestionalby  true  that  under  these  conditions 
more  of  the  volatile  and  viscous  hydrocarbons  are  fixed,  but  of  necessity  there  is  an 
insufficient  supply  of  oxygen  in  the  bottom  of  the  fuel  bed,  this  being  the  result  of 
mass  action  in  combination,  as,  for  instance,  the  insulating  and  diluting  effect  of  ash 
formation,  etc. 

A  certain  portion  of  the  fuel  escaping  unburned  to  the  ash  zone  is  carried  off  in 
the  cleaning  of  the  grates,  moreover,  by  reason  of  the  lack  of  oxygen  for  complete 
combination,  the  fire  dies  out  around  the  grate  or  in  the  lower  extremities  of  the  fuel 
bed.  Hence,  a  certain  portion  of  the  fuel  escaping  unburned  is  lost  by  drawing  the 
coal  with  the  ash.  This  may  be  said  to  be  an  offset  and  more  than  commensurate 
with  any  possible  saving  in  the  fixing  of  the  hydrocarbon  under  the  down-draft 
process. 

The  following  analyses  show  the  fixed  carbon  loss  in  ash  in  one  specific  instance: 

LIGNITE  FROM  WILSON  COAL  Co.,  CENTRALIA,  WASH. 

Proximate  Analysis.  Per  Cent. 

Moisture 15.7 

Volatile  matter 47 . 0 

Fixed  carbon 24 . 0 

Sulphur 0.5 

Ash.  .  12.8 


130  GAS   PRODUCERS 

ASH  WITHDRAWN,  DOWN-DRAFT  PRODUCER,  WILSON  DUST  COAL 

Analysis.  Per  Cent. 

Moisture 17.8 

Volatile  matter 9.7 

Fixed  carbon  and  sulphur 48 . 7 

Ash 23.8 

Calorific  value,  B.T.U 80.0 

Specific  gravity 1 . 42 

LIGNITE  FROM  RENTON  MINE,  WASH. 

Proximate  Analysis.  Per  Cent. 

Moisture 6.6 

Volatile  matter 52 . 3 

Fixed  carbon 28 . 0 

Sulphur 0.3 

Ash 12.8 

ASH  WITHDRAWN,  SMITH  DOWN-DRAFT  PRODUCER,  RENTON  COAL 

Analysis.  Per  Cent. 

Moisture 25 . 0 

Volatile  matter 6.6 

Fixed  carbon  and  sulphur 34 . 3 

Ash : 34. 1 

Calorific  value,  B.T.U 7600 

Specific  gravity -. 1.61 


With  up-draft  producers  the  following  would  be  the  characteristic  analysis  of  the 
ash  drawn: 

Analysis.  Per  Cent. 

Moisture 25 . 0 

Volatile  matter 5.0 

Fixed  carbon  and  sulphur 15.0 

Ash..  55.0 


The  moisture  content  of  draw  is  due  principally  to  water-sealed  producers.  It 
is  a  matter  of  record  that  the  draw  from  properly  gasified  lignite  fuel  contains  less 
waste,  or  free  carbon  and  volatile  matter  than  the  bituminous  or  anthracite  coal. 
This  may  be,  perhaps,  by  reason  of  its  low  temperature  of  distillation,  and  its  extreme 
rapidity  of  heat  propagation. 

Lignite  coals  are  widely  distributed  throughout  the  western  and  southern  sections 
of  the  United  States.  Most  lignites  can  be  successfully  used  in  the  producer  described, 


PRODUCER   TYPES  131 

probably  not  more  than  one  in  twenty  being  unacceptable.  Before  guaranteeing 
operation,  it  would  be  necessary,  however,  to  have  analyses  and  experimental  tests 
of  samples  made,  the  principal  points  to  be  determined  being  the  amount  of  volatile 
matter,  the  amount  of  fixed  carbon,  the  moisture  content,  the  fusibility  of  the  ash, 
and  the  nature  of  the  tarry  oils  or  unfixed  hydrocarbons.  Brown  lignites  often  work 
as  well  as  black,  although  they  are  usually  of  a  lower  heating  value  and  require  more 
pounds  per  mechanical  horsepower  produced. 

The  amount  of  fuel  required  will  range  from  1|  to  3  Ibs.  per  b.h.p.  per  hour,  depend- 
ing, of  course,  upon  the  heating  value  and  general  characteristics  of  lignite  used.  A 
thermal  efficiency  of  60%  is  a  safe  guaranty  in  connection  with  plants  of  this  type. 
That  is  to  say,  60%  of  the  B.T.U.  contained  in  the  original  coal  is  delivered  to  the 
engine  and  mechanical  power  is  then  calculated  by  the  number  of  B.T.U.  required 
by  the  engine  at  various  loads,  or  load  factors.  The  usual  arbitrary  used  in  rough 
calculations  being  10,000  B.T.U.  b.h.p.  per  hour. 

Lignite  producer  plants  require  about  four  gallons  of  water  per  h.p.  hour,  in  addi- 
tion to  the  amount  required  for  water  jacketing  of  the  engine.  The  gas-cleaning 
water  can,  of  course,  be  cooled,  separated  from  its  impurities,  and  re-used  where 
proper  towers,  settling  tanks,  or  separating  apparatus  is  installed. 

The  quality  of  the  gas  from  producers  of  this  type  is  affected  less  by  cleaning 
or  barring  the  producer  than  the  gas  from  anthracite  producers.  It  also  requires 
less  time  to  blast  up  the  producers,  and  the  apparatus  is  more  sympathetic,  and  has 
wider  range  in  accepting  load  variations. 

On  the  whole,  it  is  operated  with  less  labor  and  effort,  and  the  quality  of  its 
service  is  so  uniform  as  to  make  it  peculiarly  acceptable  for  variable  conditions  and 
continued  service. 


WOOD-FUEL  SUCTION  PRODUCER 

Wood,  planer  chips,  sawdust  and  corn  cobs  may  be  used  in  suction  producers 
of  almost  any  type  running  down-draft,  up-draft  producers  being  impracticable  by 
reason  of  the  necessity  for  fixing  resinous  oils.  In  the  use  of  oak  and  other  non- 
resinous  woods,  ordinary  coke  and  sawdust  scrubbers  are  sufficient  for  the  purifica- 
tion of  the  gas,  but  with  all  woods  or  fuels  of  the  resinous  type  some  form  of  mechan- 
ical separator  is  additionally  necessary,  its  interposition  being  between  the  producer 
and  the  scrubber. 

Where  wood  is  used  it  is  customary  to  use  the  ordinary  stove  size,  say  14"  + 
14" +  3".  This  gives  very  satisfactory  results. 

However,  the  wood  is  usually  cut  into  billets  approximately  2X4,  or,  say, 
3X6  inches.  Certain  woods,  such  as  fire,  are  especially  satisfactory  inasmuch  as 
they  do  not  '  char  "  or  charcoal  (a  process  somewhat  similar  to  the  coking  of 
coal)  and  hence,  blanket  or  "plug"  the  fire. 

Where  shavings  or  sawdust  chips  are  used  some  form  of  mechanical  feeder  is 
necessary. 

The  producer  should  be  water  sealed  or  of  the  Bosch  type,  and  should  preferably 


132  GAS   PRODUCERS 

have  a  water-cooled  grate,  although  f-in.  steel  bars  placed  upon  angle  irons  are  fre- 
quently used. 

The  producer  should  be  equipped  with  an  abundance  of  poke  holes,  inasmuch 
as  sawdust,  and  chips  particularly,  have  a  strong  tendency  to  burn  next  the  lining, 
creating  channels  and  chimneys.  The  mechanical  feeder  should  really  have  some 
mechanical  stoking  device  which  would  tend  to  pack  the  fuel  bed. 

The  sawdust  fire  bed  is  run  to  the  depth  of  about  30  inches.  The  air  inlets 
should  have  throttling  devices  to  prevent  excess  in  the  producer. 

The  producer  is  best  constructed  with  a  movable  hood  or  stack  for  removing 
the  smoke  \vhile  blasting  and  which  may  be  lifted  by  counterweights  or  otherwise 
while  feeding  or  poking. 

The  producer  should  have  two  air  connections  to  which  the  blast  may  be  attached. 
When  starting,  it  should  be  blasted  from  the  bottom  until  brought  up  to  heat,  after 
which  the  connection  is  reversed  and  the  producer  blasted  from  the  top  until  the  gas 
is  driven  to  the  engine. 

The  tar  from  resinous  woods  is  particularly  intractable  and  extremely  detri- 
mental to  operation  in  the  manufacture  of  power,  a  small  portion  of  the  resinous  oil 
effecting  a  clogging  of  governors,  piping,  and  connections  and  causing  the  pistons  to 
seize. 

In  the  producer  illustrated,  it  was  found  necessary  to  put  in  side  openings  above 
the  grate  to  admit  air  and  prevent  the  formation  of  soot  and  to  keep  the  fire  from 
dying  out  in  the  bottom  subtending  a  thick  bed  of  finely  powdered  charcoal  and  soot, 
and  creating  a  considerable  obstruction  to  the  passage  of  the  gas. 

The  admission  of  air  at  this  point  would  act  both  as  a  mechanical  agitator  and 
a  chemical  catalytic. 

However,  such  admission  must  be  most  carefully  arranged,  as  an  excess  tends  to 
mnke  the  producer  extremely  hot  (through  complete  combustion),  and  also  a  large 
formation  of  CO2  (with  attendant  waste).  If  a  little  air  is  admitted  the  producer 
fills  up  with  soot  and  packs  as  aforesaid.  The  mean  between  these  two  extremes 
should  be  observed. 

It  is  possible  to  use  almost  any  fuel  possessing,  say  20%  of  combustible  matter, 
in  a  producer  of  this  type.  The  writer  in  a  100-h.p.  producer  of  similar  construction 
has  obtained  a  brake  h.p.  for  about  two  and  one-half  pounds  of  straw  and  about  the 
same  amount  of  hay  gasified. 

In  practice  he  has  found  it  advantageous  to  chop  the  hay  and  straw  coarsely 
in  one  of  the  ordinary  chopping  machines  used  for  this  purpose.  After  feeding  it 
into  the  producer  it  may  be  rammed  down  with  a  square-headed  tamp. 

In  sugar  plantations  bagasse  is  equally  available  and  makes  an  excellent 
fuel. 

Smoke. — Where  bituminous  fuel  is  used  in  producers  under  the  observation  of 
"smoke-nuisance  laws  "  or  health  department  regulations,  smoke  may  be  obviated 
during  the  run  by:  (a)  properly  regulated  combustion  (sufficient  mix  of  secondary 
air);  (6)  light  and  frequent  firing;  (c)  the  maintenance  of  a  fairly  high  heat  in  the 
combustion  zone;  (d)  not  too  deep  a  distillation  zone. 

In  starting  up   the  producer  it  may  be  brought  up  to  heat  without  smoke  by  the 
use  of  wood  shavings  and  coke,  or  possibly  a  little  anthracite  coal.     After  arriving 


PRODUCER  TYPES 


133 


M3AOO  ONlanS  Hll/tt 
I'D  HO  SONINSdO  UIV    «•  XIS 


134  GAS   PRODUCERS 

at  normal  temperature  it  may  be  "switched"  to  bituminous  fuel  without  smoke  pro- 
duction by  the  precaution  of  light  firing. 

POWDERED  FUEL  ^PRODUCERS 

Probably  the  most  radical  advance  which  has  been  made  in  the  design  of  pro- 
ducers since  the  date  of  their  initial  invention,  has  been  the  adaptation  of  powdered 
fuel  to  this  branch  of  work. 

It  is  hardly  necessary  to  call  attention  to  the  peculiar  features  attendant  upon 
its  use,  and  although  it  is  likely  that  it  is  governed  by  many  intricate  laws  of  mass 
action  and  that  it  is  the  result  of  kinetic  conditions  with  which  we  are  more  or  less 
unacquainted,  for  practical  purposes  it  will  suffice  to  say  that  the  results  obtained 
are  unquestionably  due  to  intimate  mixture  of  the  elements  and  the  molecular  activity 
due  to  mechanical  agitation,  which  we  may  term  "acceleration." 

Among  the  distinct  advantages  obtained  by  the  use  of  powdered  fuel  (by  which 
we  mean  a  fuel  powdered  to  approximately  a  50  mesh,  this  size  requiring  no  pre- 
drying),  may  be  noted  the  rapidity  of  gasification,  the  service  performed  by  an 
apparatus  of  a  given  cross-section  being  four  or  five  times  that  of  the  standard  shaft 
or  cylindrical  producer. 

The  gas  produced  is  particularly  uniform  in  its  nature  by  reason  of  the  fact  that 
the  producer  does  not  suffer  from  those  changes  in  fire  bed  which  create  the  variation 
in  gas  analysis  due  to  deep  and  shallow  fire  beds,  hot  and  cold  fuel  beds,  clinker, 
chimneys,  and  channeling. 

The  "mix"  or  rate  of  feed  of  the  various  elements  being  once  established,  the 
output  may  be  said  to  be  constant  and  the  analysis  of  the  gas  and  its  calorific  value 
exceedingly  uniform. 

Another  distinct  feature  is  that  of  the  saving  from  stand-by  losses,  stand-by 
loss  of  a  powdered  fuel  producer  being  almost  nil,. it  being  possible  to  start  it  up 
from  a  cold  producer  to  a  gasifying  apparatus  within  some  ten  minutes  of  time,  the 
only  loss  being  the  heat  necessary  to  bring  the  apparatus  up  to  a  temperature  of 
gasification.  Inasmuch  as  the  stand-by  losses  from  the  average  producer  are  usually 
figured  at  6  to  8%  of  the  maximum  rated  consumption,  this  feature  alone  is  one  of 
considerable  importance. 

The  third  claim  for  an  apparatus  of  this  class,  and  one  of  considerable  import, 
is  the  lessening  of  labor,  the  feeding  of  the  producer  being  entirely  mechanical  and 
the  stoking  entirely  obviated,  there  being  neither  clinkers  to  be  barred  down  nor  ash 
in  any  quantity  to  be  removed,  nor  is  there  the  continuous  poking  necessary  in  all 
of  the  types  of  producers,  to  maintain  a  uniform  and  compact  fire  bed. 

The  problem  of  ash  and  clinker,  together  with  the  tar  and  other  hydrocarbon 
impurities,  are  also  taken  care  of  in  this  apparatus.  The  first  and  second  items  are 
reduced  to  a  minimum,  there  being  none  of  the  untractable  clinker  which  is  unques- 
tionably the  most  difficult  feature  of  solution  in  the  practical  operation  of  the  modern 
producer. 

In  the  last  feature,  that  of  the  tar  and  other  impurities,  the  distillation  of  the 
coal  is  so  complete  that  the  tar  is  broken  up  by  the  use  of  hydrocarbons,  and  as  these 
hydrocarbons  may  be  fairly  said  to  represent  from  15  to  20%  of  the  value  of  the 


PRODUCER   TYPES  135 

totnl  available  heat  of  the  coal,  their  recovery,  or  rather  retention  in  the  gas,  is  an 
extremely  necessary  economy.  The  tar,  as  a  matter  of  fact,  in  a  powdered  fuel  pro- 
ducer is  more  thoroughly  dissociated  and  gasified  than  even  in  producers  of  the 
down-draft  type,  while  the  conditions  of  the  fire  bed  and  the  production  of  lamp- 
black, which  are  drawbacks  to  these  types,  are  not  met  with. 

The  increased  calorific  value  of  the  gas  supplied  by  apparatus  of  this  kind  is 
probably  due:  First,  to  the  intense  heat  developed  in  the  plume  of  combustion,  and 
a  resultant  complete  distillation  of  all  volatile  hydrocarbons,  the  total  efficiency  of 
which  alone  represents  more  than  20%  of  the  combustible.  Second,  the  intimacy 
of  air  and  carbon  mixture,  due  to  the  pulverization  of  the  latter,  and  the  tempera- 
ture aforesaid,  creates  a  positive  reaction,  and  there  being  no  chimney  or  channels, 
there  is  no  uncombined  air  or  "air  excess"  escaping  to  the  top  of  the  fire,  and  there 
consuming  the  lighter  hydrocarbons.  The  destruction  of  these  in  this  manner  is 
larger  in  the  ordinary  shaft  producer  than  is  usually  realized. 

As  much  as  97%  of  the  available  carbon  in  the  fuel  has  been  turned  into  gaseous 
carbon  in  pulverized  fuel  producers. 

Some  idea  of  the  intimacy  of  union  and  rapidity  of  molecular  action  may  be 
gained  in  case  of  powdered  fuel,  by  noting  the  conditions  obtained  in  cement  firing 
for  powdered  fuel  (100  mesh)  where  the  following  conditions  will  be  observed. 

In  shaft  kilns  where  direct  firing  is  used,  the  fuel  being  lump,  slack  or  run-of- 
mine  coal,  an  excess  of  air  amounting  to  300  cubic  feet  per  pound  of  coal,  is  frequently 
required.  In  the  use  of  powdered  fuel,  as  aforesaid,  in  rotary  kilns  only  150  cubic 
feet  per  pound  of  powdered  fuel  is  required,  or  practically  the  theoretical  quota 
necessary  for  chemical  union  or  complete  combustion. 

The  resaon  for  the  excess  of  air  necessary  for  complete  combustion,  which  is  so 
great  in  direct  firing  and  exists  even  in  gaseous  combustion,  is  governed  by  the  laws 
of  mass  action. 

These  laws  are  extremely  intricate  in  their  working  and  their  formularization  a 
matter  of  great  difficulty. 

Briefly  and  simply  stated,  when  C  burns  to  C02  or  CO  to  C02,  the  oxygen  in 
immediate  contact  with  the  fuel  is  combined,  and  the  resultant  molecule  forms  to 
some  extent  an  obstacle  to  the  passage  of  fresh  or  additional  oxygen  for  combination 
with  a  further  amount  of  fuel. 

Thus  the  rate  of  combination  tends  to  fall  off.  Assuming  pressure  and  temper- 
ature to  remain  constant,  the  combinations  becoming  less  and  less  frequent,  the 
reaction  being  slower  as  compared  with  the  total  mass  present  or  the  elements  involved. 

To  overcome  or  offset  this  condition  an  excess  of  air  is  necessary,  that  is  to  say, 
this  offset  being  to  compensate  the  lessening  frequency  of  the  combinations  due  to 
the  stagnation  or  interference  of  the  newly  combined  molecule  aforesaid. 

A  common  analogy  of  this  may  be  seen  in  the  mixing  of  sugar  in  coffee  or  salt 
in  water,  these  combinations  requiring  mechanical  agitation  or  "stirring"  with  a 
spoon  in  order  to  accelerate  the  reaction.  If,  in  the  example  named,  the  amount 
or  volume  of  sugar  is  increased,  a  larger  amount  of  combination  of  sugar  and  water 
solution  will  be  produced  within  a  given  time,  even  without  mechanical  acceleration. 
This  is  because  more  surface  is  presented  for  action  and  more  atoms  are  brought  in 
juxtaposition  or  contact. 


136  GAS   PRODUCERS 

The  theory  of  powdered  fuel  lies  along  these  lines,  that  is  to  say,  the  mass  action 
is  relatively  greater,  there  being  a  larger  number  of  atoms  or  molecules  of  the  respec- 
tive elements  in  contact  per  unit  of  time  and  space. 

In  recapitulation,  therefore,  it  will  be  seen  that  the  theory  of  mass  action  depends 
upon  a  diminuendo  of  chemical  propagation,  the  diminishing  curve  being  due  to  the 
obstacles  presented  by  the  newly  oxidized  matter  and  the  constant  increase  of  both 
time  and  space  separating  more  remote  particles. 

Naturally  those  atoms  or  molecules  in  closest  juxtaposition  will  unite  most 
readily  and  rapidly,  while  those  at  a  distance  require  more  time  and  greater  travel 
before  locating  an  affinity. 

The  circulation  required  by  the  residual  particles  of  the  elements,  towards  the 
latter  part  of  a  reaction  of  any  given  unit  or  volume,  is  therefore  comparatively  very 
great,  theoretically  having  to  pass  through  or  around  the  entire  mass  before  the 
uncarbonized  particle  of  oxygen  meets  the  unoxidized  particle  of  carbon  or  vice  versa. 

This  is  again  seen  in  the  dissolution  of  salt  in  water,  as  before  cited.  This  reac- 
tion is  at  first  very  rapid,  becoming  slower  and  slower  as  the  virgin  or  uncombined 
particles  must  travel  farther  and  farther  to  secure  their  complement  of  combination. 

In  practice,  of  course,  for  the  reason  herein  suggested,  complete  reaction  never 
takes  place,  the  residual  or  uncombined  elements  being  carried  away  by  convection 
currents,  gravitation,  etc.,  before  the  search  for  combination  (which  if  indefinitely 
prolonged  will,  according  to  the  laws  of  probabilities,  occur)  could  be  completed. 

By  increasing  the  amount  of  one  element  therefore  (as  air)  three  or  four  hundred 
times,  a  smaller  proportion  of  this  uncombined  matter  escapes.  This  is  the  case  in 
the  instance  of  direct  firing,  while  in  the  case  of  gaseous  or  powdered  fuel,  the  mechan- 
ical intermixture  or  interrelation  of  the  elements  is  so  much  more  intimate,  that  the 
loss  is  reduced  to  a  minimum,  and  the  "complete"  combination  may  be  attained 
with  but  small  excess. 

As  an  offset,  however,  to  the  salvage  effected  by  complete  combustion  under 
conditions  of  air  excess,  there  is  the  necessity  of  heating  a  larger  volume  of  air  and 
bringing  it  up  to  the  flame  temperature,  necessitating  a  corresponding  expenditure 
of  useful  heat. 

The  conditions  as  cited  above,  as  occurring  in  the  matter  of  complete  combus- 
tion, do  not  prevail  entirely  in  the  production  of  producer  gas,  which  is  that  of  incom- 
plete combustion.  But  this  discussion  has  been  promoted  in  order  to  show  the 
analogy  between  direct  firing  and  gaseous  or  powdered  fuel  firing,  and  to  illustrate 
some  of  the  laws  of  mass  action,  which  control  and  materially  govern  the  production 
of  gas  under  the  powdered  fuel  system,  and  accounts  for  the  low  N2  and  CO2  and 
the  high  CO  and  CH4  in  the  gas. 

THE  HIRT  POWDERED  FUEL  PRODUCER 

The  following  is  a  rough  memorandum  of  the  operation  of  the  Hirt  powdered 
fuel  producer  at  the  Leetsdale  plant  of  the  Riter-Conley  Company. 

The  size  of  the  producer,  inside  diameter,  6  ft.  6  ins.  Height,  outside,  16  ft. 
The  diameter  within  the  producer  is  reduced  to  a  narrow  throat  by  offsetting  the 
fire-brick  linings.  This  throat  forms  a  vortex  through  which  combustion  products 


PRODUCER   TYPES  137 

pass,  and  just  above  which  the  steam  used  as  an  endothermic  agent  is  admitted  by 
means  of  axial  nozzles. 

The  blower  and  coal  crusher  consist  of  a  small  self-contained  machine  of  a  very 
compact  nature,  the  whole  being  operated  by  a  direct-connected  motor.  The  coal 
passed  is  blown  through  a  short  tuyere  which  enters  the  producer  near  the  base  at 
an  opening  tangential  to  its  axis. 

The  operation  of  the  producer  is  as  follows:  Coal  being  placed  in  the  hopper  it 
is  fed  into  the  crusher  at  the  outlet  of  which  it  is  caught  by  the  blast  and  blown  into 
the  producer.  The  blast  pressure  and  the  speed  of  the  crusher  are,  of  course,  capable 
of  separate  adjustment  and  regulation,  thereby  obtaining  a  wide  range  of  volume, 
amount  of  fuel,  and  rate  of  flow. 

The  crusher  and  blower  being  started,  the  producer  is  fired  by  impinging  the 
blast  upon  a  few  handfuls  of  oily  waste  which  have  been  previously  ignited.  The 
vortex  created  by  the  contraction  of  the  linings  in  the  center  of  the  producer  sub- 
tends a  conical  flame.  Starting  of  the  producer  requires  30  minutes.  The  producer 
being  run  as  a  furnace,  that  is  to  say,  with  complete  combustion  tor  15  minutes,  which 
is  succeeded  by  a  dry  run  without  steam  for  15  minutes,  after  which  the  steam  is 
slowly  turned  on. 

From  a  rough  calculation,  the  output  of  this  producer  was  equivalent  to  2500 
b.h.p.  at  an  assumed  engine  efficiency  of  10,000  B.T.U. ;  there  was,  however,  no  indi- 
cation that  the  producer  would  run  at  its  maximum  capacity. 

The  auxiliary  apparatus  before  mentioned,  consisting  of  a  combined  crusher 
and  fan  blower,  reduces  the  coal  to  a  40-mesh,  delivering  same  to  the  fan  when  it  is 
blown  to  the  producer  at  about  1  pound  pressure.  The  power  required  to  operate 
the  outfit  was  about  f  of  1%  of  the  producer  output.  The  labor  consisted  of  one 
man,  there  being  no  barring  down,  poking,  or  stoking  required,  his  work  being 
merely  the  necessary  regulation  and  adjustment  of  the  apparatus,  and  the  oiling  of 
the  moving  parts. 

Practically  all  fuel-bed  difficulties  from  ash,  clinker,  honeycombing,  channeling, 
and  the  co-related  evils  of  necessary  stoking,  are  overcome  in  this  producer  by  the 
slagging  of  the  ash,  which  is  fused  and  drawn  off  as  a  slag  at  the  bottom  of  the  pro- 
ducer in  the  most  satisfactory  manner. 

By  reason  of  this,  practically  any  fuel,  no  matter  how  inferior  or  low  in  com- 
bustible content,  may  be  used  with  equal  satisfaction.  The  producer  being  success- 
fully tested  upon  anthracite  coal,  coke,  bituminous,  and  lignite  coals.  The  principal 
test  was  made  on  a  bituminous  coal  having  the  following  analysis: 

Moisture 5 . 02% 

Volatile  matter 17.5  % 

Fixed  carbon 72.48% 

Ash 9.5% 

The  residue  in  the  form  of  slag  when  analyzed,  showed  the  following,  upon  two 
separate  samples: 

i.  ii. 

Silica 19.8%         40.9% 

Iron 1.2%         14.20% 


138  GAS   PRODUCERS 

The  following  are  copies  of  several  analyses   made  from  gas  supplied  by  this 
producer: 


CO  

i. 
2.3  .  7 

11. 
27.5 

in. 
26.5 

IV. 

27.0 

CO2  

3.9 

2.8 

2.9 

5 

H2  

10.0 

11.5 

11.0 

9  5 

cm. 

5.0 

4.5 

4.7 

5 

It  is  a  well-known  fact  that  in  the  shaft  producer  there  may  6e  said  to  be  three 
general  zones,  the  first  two  being  that  of  primary  and  secondary  distillation,  and  the 
third  being  that  of  oxidation. 

In  the  first,  particularly  in  certain  classes  of  bituminous  coals  and  lignites,  the 
distillation  commencing  with  the  evaporation  of  the  water  vapor  and  moisture,  com- 
mences at  a  relatively  low  temperature,  and  is  only  really  complete  upon  reaching 
approximately  1300°  F.  in  the  second  distillation  zone,  or  just  prior  to  commencing 
oxidation. 

As  may  be  readily  seen,  this  volatilization  or  distillation  of  volatile  matter  is 
much  more  rapid  than  the  action  of  oxidation,  the  ratio  average  with  bituminous 
coals  being  perhaps  10  to  1,  and  being  still  more  rapid  in  the  case  of  certain  lignites. 

It  will  also  be  seen  that  the  heavy  hydrocarbons  thus  distilled  being  infinitely 
richer  than  carbonic  oxide,  there  must  necessarily  be  wide  limits  between  the  high 
and  low  value  of  the  gas,  the  former  being  reached  during  the  maximum  moment  of 
distillation,  and  the  latter  after  distillation  is  completed,  and  the  gas  is  merely  the 
resultant  product  of  oxidation. 

Now,  it  is  also  very  apparent  that  where  powdered  fuel  is  used,  the  distillation 
and  oxidation  may  be  said  to  be  practically  simultaneous,  hence  an  increased  uni- 
formity in  the  gas  due  to  an  identity  of  its  composition,  which  is  almost  continuous. 

It  would  be  obvious  in  this  process  that  the  difficulties  obtained  from  caking  or 
coking  fuel  will  be  obviated.  The  difficulty  under  such  conditions  in  shaft  producers 
being  for  the  fuel  to  cohere  in  mats,  reducing  the  suface  contact,  and  hence  the  chem- 
ical union  of  the  elements,  and  at  the  same  time  creating  a  porous  fuel  bed,  subject  to 
chimneys  and  fissures. 

THE  MARCONET  POWDERED  FUEL  PRODUCER 

A  description  of  a  gas  producer  recently  developed  in  France,  which  utilizes  all 
grades  and  kinds  of  fuel  with  equal  facility,  was  given  in  Le  Genie  Civil,  briefly  as 
follows:  The  problem  of  utilizing  all  grades  of  fuel  in  the  gas  producer  has  been  satis- 
factorily solved  in  France  by  the  invention  of  M.  Marconet  of  a  producer  into  which 
the  coal  is  introduced  in  a  finely  divided  condition.  M.  Marconet  has  succeeded  in 
developing  a  gas  producer  which  utilizes  with  equal  facility  fuels  entirely  free  from 
volatile  constituents,  such  as  coke  dust  and  fuels  in  which  the  proportion  of  volatile 
matter  reaches  as  high  as  30  to  35%.  Further,  the  percentage  of  ash  is  a  matter 
of  indifference,  the  producer  working  equally  well  with  fuels  containing  5  or  30% 
of  incombustible  matter,  and  good  results  have  been  obtained  with  even  bituminous 
shales  containing  70%  of  ash.  Finally,  not  the  least  important  advantage  possessed 


PRODUCER   TYPES  139 

by  this  producer  is  the  fact  that  it  is  able  to  utilize  the  fine  coal  and  slack  which 
ordinarily  goes  to  waste  in  coal  mining  and  washing  operations.  These  results  are 
obtained  by  charging  the  producer  continuously  with  pulverized  fuel,  thus  avoiding 
all  the  difficulties  encountered  in  the  ordinary  type  of  producer  with  its  intermittent 
charging  of  lump  coal. 

The  use  of  pulverized  fuel  makes  grinding  necessary.  This  is  done  usually  in  tube 
mills,  the  cost  under  ordinary  conditions  being  from  If  to  2  francs  per  ton.  The  fuel 
is  introduced  into  the  producer  by  means  of  an  apparatus  which  resembles  in  principle 
the  carbureter  of  a  gasoline  motor;  that  is,  the  air  drawrn  into  the  producer  carries 
with  it  the  pulverized  fuel  with  which  it  becomes  thoroughly  mixed  before  it  enters 
the  producer  proper. 

The  producer  proper  is  cylindrical  in  form  and  is  lined  with  some  sort  of  refrac- 
tory material.  The  mixture  of  air  and  coal  dust  enters  at  the  bottom  of  the  cylinder 
and  tangentially  to  its  circumference.  Combustion  is  set  up  in  the  first  place  by  the 
introduction  into  the  producer  of  a  few  pieces  of  burning  wood,  the  admission  of  air 
and  fuel  being  cut  down  to  convenient  proportions.  The  temperature  rises  rapidly 
and  full  working  conditions  are  attained  in  a  very  short  time.  The  incombustible 
materials  are  projected  by  centrifugal  force  to  the  walls  of  the  producer  where  they 
collect  in  small  liquid  globules  and  finally  run  down  into  a  slag  at  the  bottom.  This 
slag  is  tapped  off  every  six  or  eight  hours  through  a  tap  hole  similar  to  that  of  a 
cupolti,  an  arrangement  which  gives  every  satisfaction.  This  slag  varies  in  appear- 
ance with  different  kinds  of  coal.  It  is  very  rare  to  find  a  coal  of  which  the  incom- 
bustible constituents  will  not  settle  in  this  manner,  and  such  difficulties  can  generally 
be  removed  either  in  the  grinding  or  in  the  charging  of  the  fuel. 

To  obtain  regular  working  of  the  apparatus,  it  is  of  prime  importance  that  the 
proportions  of  air  and  coal  should  be  capable  of  exact  regulation  and  maintenance 
at  all  rates  of  working;  in  other  words,  that  the  charging  device  should  have  a  simple 
and  efficient  regulating  mechanism.  M.  Marconet  has  achieved  this  result  in  the 
following  manner: 

The  pulverized  fuel  is  charged  into  a  hopper  from  whence  it  falls  by  gravity  on 
to  a  horizontal  revolving  plate  placed  about  one  centimeter  below  the  hopper.  This 
plate  is  revolved  by  means  of  a  friction  roller,  working  on  its  under  side,  the  distance 
of  which  from  the  axis  of  the  plate  can  be  regulated  during  working.  During  the 
rotation  of  the  plate  the  fuel  is  met  by  a  scraper  placed  obliquely,  which  causes  the 
coal  to  fall  in  a  thin  stream  on  a  second  plate,  which  may  be  adjusted  at  any  angle 
to  the  horizontal.  In  sliding  off  this  latter  place  the  pulverized  fuel  passes  the  intake 
of  a  fan  which  supplies  air  to  the  producer  and  is  drawn  in  along  with  the  air,  the 
mixing  process  being  complete. 

Since  the  rate  of  working  of  the  producer  varies  with  the  speed  of  the  fan,  and  the 
speed  of  rotation  of  the  feed  plate  depends  entirely  upon  the  speed  at  which  the  fan 
is  driven,  the  supply  of  coal  varies  automatically  with  the  air  supply.  Further  regu- 
lation of  the  fuel  supply  may  be  obtained  by  changing  the  position  of  the  friction 
roller,  raising  or  lowering  the  rotating  plate  to  increase  or  lessen  the  flow  of  coal  from 
the  hopper,  altering  the  position  of  the  scraper,  or  changing  the  angle  of  inclination 
of  the  adjustable  plate.  In  the  latter  case,  changing  the  angle  of  inclination  of  the 
plate  alters  the  distance  of  the  falling  stream  of  coal  from  the  intake  of  the  fan.  By 


140  GAS   PRODUCERS 

this  means  tne  fineness  of  the  coal  supply  to  the  producer  can  be  regulated,  as  the 
size  of  the  lump  that  can  be  drawn  in  by  the  current  of  air  depends  upon  the  distance 
of  the  stream  of  fuel  from  the  fan  intake.  A  receptacle  is  provided  into  which  the 
larger  particles  uneffected  by  the  air  current  fall,  whence  they  are  returned  to  the 
tube  mill  for  further  grinding. 

A  600-h.p.  unit  has  already  been  constructed  on  this  system  and  put  in  successful 
operation.  This  producer  occupied  a  space  1.8  by  3  meters  in  height. 

The  high  temperature  produced  at  the  moment  of  combustion  and  the  thorough 
mixing  of  the  gases  by  their  rotary  movement  in  the  producer  has  the  effect  of  com- 
pletely breaking  up  the  heavy  hydrocarbons  into  gaseous  products  of  simple  chemical 
combination.  After  eighteen  months'  operation  with  coals  containing  30  to  35%  of 
volatile  matter  no  trace  of  tarry  products  has  been  found.  The  absence  of  tar  makes 
the  cleaning  of  the  gas  an  easy  matter,  as  it  is  necessary  only  to  cool  it  and  to  remove 
any  dust  which  may  be  carried  over. 


CHAPTER  V 
MOVING  GASES 

Rotary  Gas  Blower. — A  rotary  blower  for  handling  hot  gas  is  described  by  Ingalls 
as  follows:  A  rotary  blower,  or  exhauster,  is  placed  in  the  gas  flue  between  the  gas 
producer  and  combustion  chamber  for  drawing  the  gas  from  the  producer  and  forcing 
it  into  the  combustion  chamber.  This  exhauster  is  run  at  uniform  speed  and  pro- 
duces a  uniform  movement  of  gas  in  the  flue,  automatically  retarding  or  promoting 
movement  in  the  producer,  accordingly  as  there  is  a  tendency  to  produce  more  or 
less  than  the  required  amount  of  gas.  The  exhauster  in  the  gas  flue  therefore  coop- 
erates with  the  blast  beneath  the  fire  to  lessen  or  promote  th'e  production  of  gas  in 
accordance  with  the  quantity  the  exhauster  takes  away,  and  when  used  with  the 
means  for  increasing  or  diminishing  the  draught  openings  beneath  the  fire,  so  as  to 
admit  more  or  less  air,  according  as  there  comes  less  or  more  than  the  amount  taken 
away  by  the  exhauster,  the  required  equilibrium  in  the  upper  part  of  the  producer 
may  readily  be  secured  and  maintained  while  the  feeding  and  stoking  openings  are 
uncovered. 

The  exhauster  comprises  wings  B',  supported  on  the  shafts  B2,  which  are  extended 
transversely  through  an  enlarged  part  of  the  flue  adapted  to  the  wings  and  supported 
in  suitable  bearings  b.  The  wings  are  operated  in  unison  by  spur-wheels  b'  on  the 
shafts  'B2.  One  of  the  shafts  is  connected  with  suitable  gearings  b2,  adapted  to  be 
operated  by  a  pulley  B3,  which  is  driven  by  a  belt  from  the  power  shaft.  In  order  to 
secure  the  exhauster  against  accidental  high  heats  and  for  keeping  the  shafts,  spur- 
wheels,  journals,  and  bearings  cool  the  shafts  are  made  hollow  in  that  part  which 
passes  through  the  gas  flue  and  for  some  distance  upon  each  side.  There  is  a  parti- 
tion c  midway  in  the  hollow  shaft.  At  the  ends  outside  the  flue  there  are  slots  or 
openings  c'  communicating  with  the  hollow  of  the  shafts.  The  wings  are  also  made 
hollow,  and  the  openings  c2  in  the  shafts  upon  each  side  of  the  partition  c  are  made 
to  communicate  with  the  hollow  of  the  wings.  Hollow  boxings  D  are  placed  upon 
the  shafts  so  as  to  cover  the  openings  c',  and  a  blast  pipe  D'  is  connected  with  the 
boxings,  whereby  a  current  of  cold  air  may  be  forced  in  at  one  side  by  an  ordinary 
blower,  passing  through  the  hollow  of  the  shafts  and  out  upon  the  opposite 
side. 

The  wings  of  the  exhauster  rub  or  move  relatively  to  one  another,  at  the  point 
of  approximate  contact,  and  thereby  cleanse  each  other  of  all  accumulations  of  soot 
upon  their  adjacent  faces,  except  to  the  extent  of  such  small  increment  as  will  make 

141 


142 


GAS   PRODUCERS 


them  fit  more  closely  together;  such  soot  as  remians  on  them  being  a  non- 
conductor, tends  to  protect  the  exhauster  by  preventing  absorption  of  heat  from 
the  gas. 

The  soot  accumulations  upon  the  interior  of  that  part  of  the  flue  where  the 
exhauster  is  located  are  subject  to  being  forced  outward  against  the  wall  by  the 
action  of  the  wings,  and  thus  tend  to  produce  objectionable  pressure  upon  or  contact 
between  the  wings  and  flue.  To  obviate  any  difficulty  on  that  account,  a  yielding 
section  is  arranged  in  the  bottom  and  top  of  the  flue  where  the  exhauster  is  located, 
which  will  give  way  before  any  dangerous  pressure  is  created  in  that  manner,  and 
also  in  case  of  accidental  explosions.  Such  a  safety-valve  is  provided  by  forming 
part  of  the  arch  E,  over  the  wings,  of  cross-bars  e  laid  sufficiently  close  to  support 
a  layer  composed  of  a  mixture  of  clay  and  coal  dust,  and  of  sufficient  weight  and 
strength  to  resist  the  gas  pressure  and  yet  yield  to  any  outward  pressure  resulting 
from  soot  accumulations  being  forced  outward  by  the  action  of  the  wings  of  the 


FIG.  84. — Hot  Gas  Exhauster. 


exhauster.  The  bottom  part  E'  is  made  of  a  layer  of  similar  composition  supported 
on  a  bed  of  dust  e',  piled  upon  the  floor  under  the  gas  flue.  These  yielding  parts  of 
the  flue  not  only  adapt  it  to  utilize  the  soot  accumulations  for  maintaining  a  close 
fit  of  the  wings  in  the  flue,  but  also  afford  means  of  easy  access  to  the  interior  of  the 
flue  for  cleaning  or  repair.  When  the  exhauster  in  the  gas  flue  is  out  of  repair,  the 
gas  is  carried  around  it  by  means  of  a  by-pass,  while  the  repairing  is  being  done.  The 
battery  of  producers  in  such  case  may  be  worked  by  means  of  the  valves  controlling 
the  communication  of  the  several  members  with  the  gas  flue  and  the  escape  chimney, 
whereby  any  single  producer  may  be  cut  out  during  the  feeding,  stoking,  and  clinker- 
ing  thereof,  the  other  producers  of  the  battery  furnishing  the  supply  of  gas  in  the 
meanwhile,  the  blast  beneath  the  fire  being  of  sufficient  strength  to  be  turned  on  with 
increased  force  at  the  same  time. 

Suction  Producer  Exhausters. — The  use  of  the  exhauster  in  connection  with  the 
suction  producer  is  multiple,  inasmuch  as  it  permits    the  aggregation  of  a  number 


MOVING   GASES  143 

of  units,  and  of  maintaining  on  the  suction  pipe  of  each  a  constant  suction  which 
prevents  "robbing."  But  even  more  important  is  its  ability  to  replace  the  holder 
and  by  circulating  the  gases  withdrawing  them  from  the  producer,  and  by  passing 
them  so  that  they  return,  a  continuous  circulation  is  kept  up,  which  prevents  the 
fire  from  deadening  at  the  lower  loads,  and  retains  to  a  great  degree  a  more  uniform 
condition  of  operation. 

From  the  producer  standpoint  it  will  be  seen  that  the  exhauster  with  a  seal  and 
by-pass  also  has  a  regulating  effect,  and  when  used  in  exhausting  the  gases  it  creates 
an  induced  draft,  which,  for  bringing  the  producer  up  to  heats  and  for  blasting,  is 
much  more  satisfactory  than  its  predecessor,  the  blower. 

But  the  more  important  function  of  the  exhauster  is  that  of  a  pump  whereby 
the  suction  stroke  of  the  engine  is  supplied  with  gas  under  a  head  or  pressure  rather 
than  below  atmosphere. 

The  efficiency  of  the  gas  engine  as  a  suction  pump  is  very  low,  and  in  many 
instances  the  interposition  of  an  exhauster  supplying  gas  at  from  three  to  six  inches 
pressure,  instead  of  the  engine  receiving  gas  at  from  one  to  seven  inches  vacuum, 
the  total  capacity  of  the  engine  has  been  increased  by  from  15  to  20%,  with  a  corre- 
sponding increase  in  efficiency. 

Some  idea  of  the  physics  involved  may  be  given  by  an  analogous  experience  of 
the  writer,  where  by  the  interposition  of  an  impeller  exhauster  which  was  connected 
in  series  with  the  inlet  of  an  air  compressor,  the  capacity  of  the  compressor  was 
increased  by  some  60%,  while  there  was  practically  no  difference  in  the  total  power 
used. 

In  this  instance  the  compressor  through  the  medium  of  the  exhauster  was  sup- 
plied with  air  at  about  six  pounds  pressure  instead  of  drawing  air  at  a  very  high 
vacuum.  It  permitted  the  compressor  cylinder  to  be  completely  filled  with  low  com- 
pressed air  at  each  stroke,  hence  a  much  larger  volume  at  each  stroke  was 
handled. 

It  will  be  seen  therefore  that  the  efficiency  of  the  impeller  exhauster  at  low 
pressure  is  materially  higher  than  that  of  a  suction  pump,  whether  in  form  of  an  air 
compressor  or  the  suction  stroke  of  a  gas  engine. 

Through  the  interposition  of  an  exhauster  in  supplying  a  gas  engine  with  gas, 
instead  of  relying  upon  suction  stroke  of  the  engine  to  supply  the  producer  with  air 
and  the  cylinder  with  gas,  an  increased  engine  capacity  is  attained,  in  some  instances 
amounting  to  10%. 

This  is  due  to  the  increased  efficiency  of  the  exhauster  over  the  engine  when 
running  as  a  suction  pump,  and  also  the  increased  density  of  the  gas  when  supplied 
under  pressure  instead  of  suction  to  the  engine  and  its  freedom  from  attenuation. 

Although  the  water-seal  or  "blow-back"  exhauster  nominally  retains  a  con- 
stant pressure  upon  the  engine,  this  pressure  must,  of  course,  vary  with  the  suction 
on  the  producer.  The  pressure  difference,  naturally,  depends  upon  the  depth  of  the 
seal,  which  is  necessarily  affected  by  a  minus  atmosphere  on  the  exhaust  side  of  the 
exhauster,  in  the  same  way  as  by  a  plus  atmosphere  on  the  pressure  side  of  the 
exhauster. 

In  the  anthracite  producer  the  variation  of  the  building  up  of  suction,  due  to 
increase  of  ashes,  clinkering,  condition  of  the  fuel  bed,  etc.,  is  comparatively  slow, 


144 


GAS   PRODUCERS 


and  the  regulation  can  be  readily  maintained  by  adding  or  subtracting  water  from 
the  seal  as  reflected  by  the  gauge  cocks. 


,3TCAM  SUPPLY 

B  - 


Blower.  Exhauster. 

FIG.  85. — Eynon-Evans  Steam  Blower  and  Exhauster. 


FIG.  86.— The  Korting 
Injector  Blower. 


With  bituminous,  and  particularly  lignite  fuels,  this  is  more  difficult,  by  reason 
of  the  extreme  rapidity  in  the  change  of  conditions  within  the  producer,  hence  the 
operation  of  the  exhauster  requires  more  constant  attention. 


MOVING   GASES 


145 


Steam  Blowers. — Gas  may  be  impelled  or  drawn  along  conduits  or  pipes  by 
means  of  the  injector  type  of  steam  blower,  such  as  is  used  in  the  fireplaces  of  steam 
boilers.  Two  of  the  Eynon-Evans  type  and  one  of  Korting  blowers  are  here  illus- 
trated and  need  no  further  explanation. 

Blowers  and  Fans  Compared. — In  most  tables  of  speeds  and  capacities,  30,000 
cubic  feet  of  air  per  hour  is  figured  to  melt  a  ton  of  iron. 

Figured  on  a  basis  of  one  pound  pressure  per  square  inch,  1000  cubic  feet  of  air 
delivered  will  require  five  horsepower. 


POSITIVE    BLOWER 

Low  Speed. 

FAN    BLOWER 

High  Speed. 

Belts  last  indefinitely  and  give  no  trouble. 

Belts  last  a  comparatively  short  time  and  are 
constantly  giving  trouble  on  account  of  their 
high  speed. 

A  comparative  statement  of  speed  to  do  a 
given  amount  of  work  would  be,  say  200  revo- 
lutions per  minute. 

The  fan  to  do  a  like  amount  of  work  under 
the  same  conditions  would  run  2000  revolu- 
tions per  minute.  This  is  a  fair  statement  of 
speed  ratios. 

Actual  tests  between  fan  and  positive  blower 
have  shown  the  latter  to  have  an  advantage  of 
50%  in  saving  of  power  over  the  fan  working 
under  the  same  conditions. 

The  enormous  speed  of  the  fan,  together  with 
the  fact  that  the  pressure  increases  the  efficiency 
decreases,  accounts  for  the  superiority  of  the 
positive  blower  over  the  fan,  as  regards  power 
and  efficiency. 

With  the  positive  blower  the  blast  is  forced 
to  the  center  of  the  stock  in  the  cupola,  thus 
producing  a  hot  fire,  a  saving  of  fuel,  hot  iron, 
and  solid  castings. 

The  non-positive  blast  produced  with  a  fan 
cannot  be  forced  as  completely  to  center  of 
stock  in  cupola,  hence  does  not  produce  as  hot 
a  fire,  but  imperfect  combustion  and  a  waste  of 
fuel. 

POSITIVE   BLAST 

NON-POSITIVE    BLAST 

Testing  Blast. — Accurate  information  regarding  the  operation  of  any  system  of 
blast  piping  can  only  be  secured  by  making  careful  tests  with  special  instruments. 

Most  important  of  the  instruments  usually  employed  for  this  purpose  is  the 
pressure  gauge,  which,  in  its  most  convenient  form  for  ordinary  work,  is  presented  in 
the  high-pressure  water  gauge.  The  large  cup  at  the  top  of  one  arm  serves  as  a 
reservoir  in  which,  because  of  its  size,  a  practically  constant  level  is  maintained,  thereby 
reducing  by  one-half  the  length  of  the  gauge  glass  that  would  otherwise  be  necessary. 
The  atmosphere  is  in  contact  with  the  surface  of  the  water  in  the  cup,  while  the  water 
in  the  other  arm  may  be  subjected  to  the  pressure  in  any  pipe  or  chamber  by  con- 
necting the  flexible  rubber  tube  therewith.  The  actual  pressure  difference  may  be 
read  in  ounces  per  square  inch,  as  indicated  by  the  level  of  the  water  in  the  graduated 
glass  tube.  The  instrument  here  shown  is  capable  of  measuring  pressures  up  to  20 
ounces. 

Such  a  gauge  is  designed  only  for  independent  observations,  so  that  an  approach 
to  a  continuous  record  can  only  be  secured  by  a  multitude  of  readings  taken  at  very 


146 


GAS   PRODUCERS 


FANS  REQUIRED  FOR  GAS  PRODUCERS 


Coal 

Cu.  Ft 

2-oz.  Pressure. 

2^-oz.  Pressure. 

3-oz.  Pressure. 

Fans. 

Burned 
in 
24  Hrs. 

Air  Re- 
quired 
perMin. 

o>  c 
.2  * 

Rev. 
perMin. 

H.P. 

Cu.  Ft. 

II 

Rev. 
per  Min. 

H.P. 

Cu.  Ft. 

§s 

tBta 

Rev. 
perMin. 

H.P. 

Cu.  Ft. 

o 

ce 

Cost. 

3  ton 

600 

2 

2290 

1.2 

688 

2 

2560 

1.5 

767 

2 

2840 

2.0 

845 

0 

$20 

4  " 

800 

3 

1910 

1.5 

967 

3 

2130 

2.2 

1080 

2 

2840 

2.0 

845 

1 

26 

5  " 

1000 

4 

1600 

2.2 

1340 

3 

2130 

2.2 

1080 

3 

2360 

3.0 

1190 

2 

33 

6  " 

1200 

4 

1600 

2.2 

1340 

4 

1790 

3.0 

1490 

4 

1980 

4.0 

1640 

3 

44 

7  " 

1400 

5 

1410 

2.7 

1690 

4 

1790 

3.0 

1490 

4 

1980 

4.0 

1640 

4 

55 

8  " 

1600 

5 

1410 

2.7 

1690 

5 

1570 

3.8 

1880 

4 

1980 

4.0 

1640 

5 

70 

9  " 

1800 

6 

1190 

4.8 

2990 

5 

1570 

3.8 

1880 

5 

1740 

5.0 

2080 

6 

90 

10  " 

2000 

6 

1190 

4.8 

2990 

6 

1330 

6.8 

3330 

5 

1740 

5.0 

2080 

7 

150 

12  " 

2400 

6 

1190 

4.8 

2990 

6 

1330 

6.8 

3330 

6 

1475 

9.0 

3670 

8 

200 

14  " 

2800 

6 

1190 

4.8 

2990 

6 

1330 

6.8 

3330 

6 

1475 

9.0 

3670 

9 

250 

16  " 

3200 

7 

1040 

6.8 

4250 

6 

1330 

6.8 

3330 

6 

1475 

9.0 

3670 

10 

325 

18  " 

3600 

7 

1040 

6.8 

4250 

7 

1160 

9.6 

4730 

6 

1475 

9.0 

3670 

20  " 

4000 

7 

1040 

6.8 

4250 

7 

1160 

9.6 

4730 

7 

1290 

13.0 

5200 

22  " 

4400 

8 

907 

9.5 

5810 

7 

1160 

9.6 

4730 

7 

1290 

13.0 

5200 

24  " 

4800 

8 

907 

9.5 

5810 

8 

1010 

13.0 

6440 

7 

1290 

13.0 

5200 

26  " 

5200 

8 

907 

9.5 

5810 

8 

1010 

13.0 

6440 

7 

1290 

13.0 

5200 

28  " 

5600 

8 

907 

9.5 

5810 

8 

1010 

13.0 

6440 

8 

1120 

17.0 

7100 

30  " 

6000 

9 

700 

15.5 

9530 

8 

1010 

13.0 

6440 

8 

1120 

17.0 

7100 

32  " 

6400 

9 

700 

15.5 

9530 

8 

1010 

13.0 

6440 

8 

1120 

17.0 

7100 

34  " 

6800 

9 

700 

15.5 

9530 

9 

780 

21.8 

10600 

8 

1120 

17.0 

7100 

36  " 

7200 

9 

700 

15.5 

9530 

9 

780 

21.8 

10600 

9 

865 

28.0 

11700 

38  " 

7600 

9 

700 

15.5 

9530 

9 

780 

21.8 

10600 

9 

865 

28.0 

11700 

40  " 

8000 

9 

700 

15.5 

9530 

9 

780 

21.8 

10600 

9 

865 

28.0 

11700 

42  " 

8400 

9 

700 

15.5 

9530 

9 

780 

21.8 

10600 

9 

865 

28.0 

11700 

44  " 

8800 

9 

700 

15.5 

9530 

9 

780 

21.8 

10600 

9 

865 

28.0 

11700 

46  " 

9200 

9 

700 

15.5 

9530 

9 

780 

21.8 

10600 

9 

865 

28.0 

11700 

48  " 

9600 

10 

612 

21.0 

13100 

9 

780 

21.8 

10600 

9 

865 

28.0 

11700 

50  " 

10000 

10 

612 

21.0 

13100 

9 

780 

21.8 

10600 

9 

865 

28.0 

11700 

Coal 

Cu.  Ft. 

4-oz.  Pressure. 

5-oz.  Pressure. 

6-oz.  Pressure. 

Fans. 

Burned 

Air  Re- 

in 
24  Hrs. 

quired 
perMin. 

02  fe 

Rev. 
perMin. 

H.P. 

Cu.  Ft. 

JS 

OQfe 

Rev. 
perMin. 

H.P. 

Cu.  Ft. 

02  En 

Rev. 
per  Min. 

H.P. 

Cu.  Ft. 

g 

33 

Cost. 

3  ton 

600 

1 

3660 

2.2 

676 

1 

4100 

3.1 

755 

1 

4500 

4.1 

832 

0 

$20 

4  " 

800 

2 

3260 

3.2 

977 

2 

3650 

4.5 

1095 

1 

4500 

4.1 

832 

1 

26 

5  " 

1000 

3 

2710 

4.5 

1375 

2 

3650 

4.5 

1095 

2 

4000 

5.9 

1200 

2 

33 

6  " 

1200 

3 

2710 

4.5 

1375 

3 

3030 

6.3 

1540 

2 

4000 

5.9 

1200 

3 

44 

7  " 

1400 

4 

2280 

6.2 

1900 

3 

3030 

6.3 

1540 

3 

3320 

8.3 

1690 

4 

55 

8  " 

1600 

4 

2280 

6.2 

1900 

4 

2560 

8.7 

2130 

3 

2800 

8.3 

1690 

5 

70 

9  " 

1800 

4 

2280 

6.2 

1900 

4 

2560 

8.7 

2130 

4 

2800 

11.5 

2340 

6 

90 

10  " 

2000 

5 

2000 

7.9 

2410 

4 

2560 

8.7 

2130 

4 

2800 

11.5 

2340 

7 

150 

12  " 

2400 

5 

2000 

7.9 

2410 

5 

2240 

11.1 

2700 

5 

2450 

14.5 

2970 

8 

200 

14  " 

2800 

6 

1700 

13.9 

4250 

6 

1900 

19.5 

4760 

5 

2450 

14.5 

2970 

9 

250 

16  " 

3200 

6 

1700 

13.9 

4250 

6 

1900 

19.5 

4760 

6 

2080 

25.6 

5220 

10 

325 

18  " 

3600 

6 

1700 

13.9 

4250 

6 

1900 

19.5 

4760 

6 

2080 

25.6 

5220 

20  " 

4000 

6 

1700 

13.9 

4250 

6 

1900 

19.5 

4760 

6 

2080 

25.6 

5220 

22  " 

4400 

7 

1480 

19  7 

6030 

6 

1900 

19.5 

4760 

6 

2080 

25.6 

5220 

24  " 

4800 

7 

1480 

19.7 

6030 

7 

1660 

27.6 

6750 

6 

2080 

25.6 

5220 

26  " 

5200 

7 

1480 

19.7 

6030 

7 

1660 

27.6 

6750 

6 

2080 

25.6 

5220 

28  " 

5600 

7 

1480 

19.7 

6030 

7 

1660 

27.6 

6750 

7 

1820 

36.4 

7420 

30  " 

6000 

7 

1480 

19.7 

6030 

7 

1660 

27.6 

6750 

7 

1820 

36.4 

7420 

32  " 

6400 

8 

1290 

26.9 

8250 

7 

1660 

27.6 

6750 

7 

1820 

36.4 

7420 

34  " 

6800 

8 

1290 

26.9 

8250 

8 

1460 

37.7 

92?1 

7 

1820 

36.4 

7420 

36  " 

7200 

8 

1290 

26.9 

8250 

8 

1460 

37.7 

9220 

7 

1820 

36.4 

7420 

38  " 

7600 

8 

1290 

26.9 

8250 

8 

1460 

37.7 

9220 

8 

1600 

51 

10120 

40  " 

8000 

8 

1290 

26.9 

8250 

8 

1460 

37.7 

9220 

8 

1600 

51 

10120 

42  " 

8400 

9 

995 

44.2 

13500 

8 

1460 

37.7 

9220 

8 

1600 

51 

10120 

44  " 

8800 

9 

995 

44.2 

13500 

8 

1460 

37.7 

9220 

8 

1600 

51 

10120 

46  " 

9200 

9 

995 

44.2 

13500 

8 

1460 

37.7 

9220 

8 

1600 

51 

10120 

-18  " 

9600 

9 

995 

44.2 

13500 

9 

1110 

62 

1  5200 

8 

1600 

51 

10120 

50  " 

10000 

9 

995 

44.2 

13500 

9 

1110 

62 

15200 

8 

1600 

51 

10120 

MOVING   CASKS 


147 


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COCO<M<M<Ni-*^H^-:<'-'^ 


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^H  --I  (N  CC  •*  1^  O 


CO  (N  IN  Ol 


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^H  ^H  (N  CC  1C  00  ~* 


os  o  CD       10 


Sooooo-^c^ooooc* 
M(M<MiOCCOi'*C«I-^lO5CO 
rt<OC30cDCO-HOiOOt>'5O<*11* 

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re  co  •*       (N       "5 


HS  «(S  ^S  HC. 


HS  «£  HS 

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ooooooooooo 
>c  x  "5  c^  «r  cc  cc  x  -t  o)  -o 

-rocreccococoor^eO'H 


>c  c^i  -*  CD  t^  ce  oo 


CO 
1C 


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1C  CO  •*  X  TO  00  (N 


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00  (N  O5         CO  <M 


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148 


GAS   PRODUCERS 


short  intervals.  The  impracticability  of  such  a  method  points  to  the  advantages  of 
an  instrument  which  by  its  own  operation  records  the  changes  in  the  intensity  of  the 
blast.  Such  is  the  blast  pressure  recorder  shown  herewith.  The  instrument,  which 


FIG.  88. — Blast  Pressure  Recorder. 


FIG.  87. — Water  Gauge  for  High  Pressure. 


FIG.  89. — Anemometer. 


is  specially  constructed  by  the  Crosby  Steam  Gage  and  Valve  Co.,  consists  of  two 
essential  parts.  First,  the  small  cylinder,  in  which  operates  a  practically  frictionless 
piston  under  the  influence  of  the  pressure.  The  motion  of  this  piston  is  like  that  of 
a  steam-engine  indicator,  multiplied  by  the  attached  arm,  which  carries  at  its  end 


MOVING  GASES  149 

a  reservoir  containing  ink.  The  second  essential  portion  is  the  dial  or  chart,  which 
is  usually  graduated  so  as  to  indicate  the  pressure  or  vacuum  in  inches  of  water.  This 
chart,  which  is  of  paper,  is  held  in  place  upon  a  circular  plate  which  is  caused  to  revolve 
by  a  system  of  clockwork.  The  point  of  the  ink  reservoir,  being  kept  elastically  in 
contact  with  the  revolving  dial,  continuously  records  all  variations  in  the  draft. 

The  simplest  instrument  for  determining  the  volume  of  air  flowing  through  a 
given  passage  or  orifice  is  the  anemometer.  This  consists  of  a  delicate  fan  wheel 
whose  motion  is  transmitted  to  a  system  of  gearing  within  the  case.  This  movement 
is  indicated  by  the  hands  upon  the  dial,  from  which  may  be  read  the  velocity  in  feet 
per  minute,  which,  multiplied  by  the  area  of  passage,  gives  the  volume.  The  instru- 
ment here  shown  is  suitable  for  comparatively  low  velocities. 

Volume  by  Pitot  Tubes. — The  volume  of  air  discharged  from  an  orifice  or  pipe 
is,  theoretically,  equal  to  the  product  of  the  velocity  of  the  air  flowing  and  the  area 
of  the  orifice.  Hence  for  the  calculation  of  volume  the  velocity  is  an  important  fac- 
tor. To  determine  the  velocity  the  Pitot  tube  is  commonly  used,  as  shown  in  the 


THERMOMETER-'' 


FIG.  90. — Pitot  Tube  Arrangement,  showing  Location  of  Test  Pipe  for  Cupola  Blast. 

accompanying  illustration.  It  should  be  inserted  in  the  center  of  a  straight  run  of 
blast  pipe  within  about  ten  feet  of  the  blower.  One  part  of  the  Pitot  tube  trans- 
mits the  total  pressure,  which  is  the  sum  of  the  static  pressure  and  the  velocity  pres- 
sure. The  other  part  in  communication  with  the  slots,  as  shown  above,  transmits 


61ATJO  PRESSURED,  ^tOTAl  EBEBSUHE 


If 

'HOT  TUBE I  I 


FIG.  91. — Arrangement  of  Tubes. 

the  static  pressure.  Evidently  the  difference  is  the  velocity  pressure.  Each  is  con- 
nected to  a  water  gauge,  which  should  show  magnified  readings  so  that  the  difference 
may  be  accurately  determined. 

Great  care  should  be  exercised  in  measuring  the  velocity  pressure,  and  the  instru- 
ments should  be  carefully  calibrated.  In  the  ordinary  blast  pipe  for  conducting  air 
from  the  blower  to  the  cupola  or  furnace,  the  velocity  should  not  exceed  two  or  three 
thousand  feet  per  minute.  As  this  velocity  corresponds  to  a  pressure  of  only  about 


150  GAS   PRODUCERS 

0.4  inch  of  water,  the  measurement  requires  care,  but  with  good  instruments  the 
reading  will  be  accurate  enough  for  all  practical  purposes. 

Volume.  —  The  velocity  pressure  being   known,   the   volume  of  free  air  passing 
through  the  pipe  may  be  determined  from  the  following  formula: 


in  which  F  =  the  volume  of  free  air  in  cubic  feet  per  minute; 

c  =  coefficient  of  Pitot  tube,  which  should  be  determined  for  each  tube; 
a  =  area  of  pipe  in  square  feet; 
v  =  velocity  in  feet  per  minute; 
20  =  64.32; 
p  —  velocity  pressure  in  pounds  per  square  foot;   p  is  the  difference  between 

the  two  pressures  observed  on  the  Pitot  tube.  ; 
d  =  density  or  weight  per  cubic  foot  of  air  at  pressure,  temperature,  and 

humidity  at  point  of  observation; 

PI  =  absolute  pressure  of  air  in  the  pipe  in  pounds  per  square  foot; 
P  —  atmospheric  pressure  in  pounds  per  square  foot. 

Horsepower.  —  Assuming  that  the  air  is  compressed  without  cooling,  the  horse- 
power may  be  found  from  the  following: 


Horsepower  - 

in  which  V  —  volume  of  free  air  in  cubic  feet  per  minute,  as  found  above; 

P  =  pressure  of  the  atmosphere  or  suction  pressure  (absolute)  in  pounds  per 

square  foot; 
PI  =  pressure  of  compression  (absolute)  in  pounds  per  square  foot. 

High  Pressure  Blowers.  —  There  are  four  formulas  sometimes  used  in  computing 
the  power  required  by  high  pressure  blowers.  Values  obtained  from  these  formulas 
have  been  placed  in  the  form  of  curves  and  are  shown  in  the  accompanying  diagrams. 


137500- w 


Jlto5o-- 


H.R  = 


MOVING   GASES 
F(Pj-P) 


H.P.= 


33,000 

Ibs.  per  sq.in.  X  V 
200 


151 


(3) 


(4) 


Formula  No.  (1)  gives  the  horsepower  required  when  the  air  is  cooled  during 
compression  as  in  the  ordinary  air  compressor. 

Formula  No.  (2),  which  has  been  explained,  is  used  when  it  may  be  assumed  that 
the  air  is  compressed  so  quickly  that  it  does  not  have  time  to  cool  to  atmospheric  tem- 
perature as  in  nearly  all  blower  work. 


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1  23  4  5  6  7  8 

PRESSURE    IN    POUNDS    PER    SQUARE  INCH 

FIG.  92. — Power  required  by  Pressure  Blowers. 

Formula  No.  (3),  the  ordinary  "hyrdaulic"  formula  is  ordinarily  used  for  pres- 
sures up  to  5  ounces. 

Formula  No.  (4)  is  frequently  used  by  other  makers  of  positive  or  rotary  blowers 
for  determining  the  horsepower  required  for  operating  their  machines.  In  this 
formula  Y  =  the  volume  of  air  displaced  by  the  impellers,  no  allowance  being  made 
for  slippage. 

The  accompanying  illustration  is  of  a  motor-driven  high  pressure  blower  made 
by  the  Brewster  Engineering  Co.  It  is  rated  at  110  to  440  cu.ft.  per  minute, 
and  runs  at  10  Ibs.  per  sq.in.  maximum  pressure.  Its  efficiency  is  85%  at  2  Ibs.  per 
sq.in.  pressure. 


152 


GAS    PRODUCERS 


COMPRESSION  CURVES 
FOR  DIFFERENT  GASES 

GENERAL      FORMULAE:- 


=  INITIAL  VOLUME=1. 
=  FINAL  VOLUME. 
=|NITIAL  P°ESSURE. 
=FINAL  PRESSURE. 
=EXPONENT.       SEE  CURVE. 


.100  °< 


VOLUMES 

FIG.  93.— Relation  of  Volume  to  Pressure. 


FIG.  94. — Brewster  High  Pressure  Blower. 


MOVING   GASES  153 

Venturi  Meter. — The  Venturi  tube  for  measuring  gas  flow  was  described  by  Chas. 
E.  Lucke  in  Progressive  Age  (April  1,  1907,  p.  178). 

In  recent  tests  made  on  some  large  gas  engines  at  the  Lackawanna  Steel  Com- 
pany's plant  in  Buffalo,  and  reported  in  the  Journal  of  the  Am.  Soc.  Mech.  Eng.  for 
March,  1907,  a  large  Venturi  meter  was  used  as  one  of  the  four  methods  for  meas- 
uring gas.  This  meter  has  an  up-stream  and  down-stream  diameter  of  15|  inches, 
and  a  throat  diameter  of  6^  inches. 

The  formula  used  was: 


i_r— i   £±}K 
i   i     ii    i 


where  V%=  velocity  of  gas  at  the  throat  in  feet  per  second; 
p?  =  absolute  pressure  of  gas,  Ibs.  per  sq.  ft.  at  throat; 
7?i=same  at  entrance; 
V2  =  cu.ft.  per  Ib.  of  gas  at  throat; 
Vi=same  at  entrance  end  of  meter; 
.A  2  =  area  of  pipe  in  sq.ft.  at  throat; 
A  i=  same  at  entrance  end  of  meter; 
K  =  1A  for  air.     It  is  the  ratio  of  the  specific  heat  at  constant  pressure  to  that 

at  constant  volume; 
K-l 

~; 


The  corrections  were  found  to  be  as  follows: 

• 

Throat  Velocity-head  Increment  Corrections  to  Apply  to  Square  Root  of 

in  Inches  of  Water.  Velocity-head  Increment  Method 

of  Computation. 

1  0.0000 

6  0.0032 

12  0.0051 

From  these  the  corrections  were  plotted  for  each  inch.  It  was  believed  from 
the  work  done  that  the  Venturi  meter  was  the  most  accurate  method  used,  and  it  is 
freely  recommended  to  all  who  have  large  quantities  of  gas  to  measure,  even  when 
the  pressure  on  that  gas  fluctuates  as  violently  as  it  may  with  a  number  of  gas  engines 
on  the  pipe  running  in  parallel. 

Data  on  Moving  Air.  —  The  pressure  of  the  atmosphere  is  due  to  the  weight  of 
the  air,  and  for  any  area  is  to  be  measured  by  the  weight  of  a  column  of  air  having 
the  given  area  as  a  base  and  a  height  equal  to  that  of  the  atmosphere.  Under 
standard  conditions  of  barometric  pressure  of  29.921  inches,  the  atmospheric  pressure 
is  14.69  Ibs.  per  sq.in.,  or  2115.36  Ibs.  per  sq.ft.  At  this  pressure  a  cubic  foot  of  dry 
air  at  50°  has  a  density  of  0.077884  Ibs.  If  air  under  this  head  were  allowed  to  flow 
freely  into  a  vacuum,  the  velocity  would  be  1321.7  ft.  per  second. 


154  GAS   PRODUCERS 

The  velocity  with  which  air  escapes  into  the  atmosphere  from  a  reservoir  is 
dependent  upon  the  pressure  therein  maintained,  and  would  vary  in  direct  propor- 
tion to  its  square  root  were  it  not  for  certain  slightly  modifying  influences.  Most 
important  of  these  is  the  change  in  density  which  results  from  a  change  in  pressure. 
This  has  been  taken  into  account  in  the  calculation  of  an  accompanying  table.  The 
volume  of  air  at  a  given  velocity  discharged  through  an  orifice  depends  upon  its 
shape,  and  is  always  less  than  that  measured  by  its  full  area.  For  a  given  effective 
area  the  volume  is  proportional  to  the  velocity,  as  is  evident  in  the  table.  The  power 
theoretically  required  to  move  a  given  volume  of  air  is  measured  by  the  product  of 
the  velocity  and  the  total  resisting  pressure.  This  power,  as  given  in  the  table  of 
velocity,  volume,  and  horsepower,  varies  as  the  cube  of  the  velocity. 

Evidently,  with  a  constant  velocity  due  to  a  constant  head,  the  actual  pressure 
must  vary  directly  as  the  density  of  the  air  and  inversely  as  its  absolute  tempera- 
ture. Therefore  if  the  velocity  remains  constant,  the  power  required  to  overcome 
the  resistance  must  be  exactly  proportional  to  the  relative  pressure. 

For  any  size  of  centrifugal  fan  there  exists  a  certain  maximum  area  over  which 
a  given  pressure  may  be  maintained,  dependent  upon  and  proportional  to  the  speed 
at  which  it  is  operated.  If  this  area,  known  as  its  "capacity  area,"  or  square  inches 
of  blast,  be  increased,  the  pressure  is  lowered  (the  volume  being  increased),  but  if 
decreased  the  pressure  remains  constant.  The  pressure  produced  by  a  given  fan, 
and  its  effective  capacity  area  being  known,  its  nominal  capacity  and  the  horsepower 
required,  without  allowance  for  frictional  losses,  may  be  determined  from  the  above 
table.  In  practice  the  outlet  of  a  fan  greatly  exceeds  the  capacity  area;  hence  the 
volume  moved  and  the  horsepower  required  are  in  excess  of  the  amounts  determined 
as  above. 

Influence  of  Temperature. — The  effect  of  increasing  the  temperature  of  the  air  is 
to  decrease  its  density,  thereby  reducing  the  weight  of  a  given  volume,  the  pressure 
required  to  produce  a  given  velocity,  and  the  power  necessary  to  move  the  same 
volume  at  the  same  velocity.  These  relations  are  presented  in  an  accompanying 
table.  The  variation  in  pressure  resulting  from  change  in  temperatures  is  indicated 
in  column  3.  As  a  consequence  the  values  given  in  column  7  are  identical  with  those 
in  column  3.  The  velocity  being  constant,  the  volume  discharged  is  also  constant, 
but  its  relative  weight  is  as  shown  in  column  4. 

If  it  be  desired  to  pass  through  the  same  orifice  a  constant  weight  of  air,  its- 
velocity  must  necessarily  vary  directly  with  its  increase  in  absolute  temperature, 
for  its  density  correspondingly  decreases.  The  velocity  necessary  to  move  the  same 
weight  is  produced  under  each  different  temperature  by  the  relative  pressure  shown 
in  column  6.  The  pressure  thus  necessary  to  produce  this  velocity  must  at  constant 
temperature  evidently  increase  with  the  square  of  the  velocity,  and  at  other  temper- 
atures must  coincidently  decrease  inversely  with  the  absolute  temperature;  that  is, 
proportionately  to  the  density. 

For  illustration  take  the  case  of  air  at  a  temperature  of  300°.  Per  the  tabler 
column  5,  the  velocity  necessary  to  move  the  same  weight  as  at  50°  is  relatively  1.49. 
For  its  production  this  would  call  for  a  relative  pressure  of  1.492  =  2.22  at  50°,  but 
at  the  temperature  of  300°  the  pressure  required  to  produce  the  given  velocity  is,  per 
column  3,  only  0.67  of  that  required  at  50°.  Hence  the  relative  pressure  required 


MOVING   GASES 


155 


at  300°  to  produce  the  velocity  necessary  to  move  the  same  weight  of  air  is  relatively 
2.22X0.67  =  1.49  times  that  which  is  necessary  to  produce  the  movement  of  the  same 
weight,  but  less  volume,  at  50°.  Under  these  conditions  of  moving  the  same  weight 
at  different  temperatures,  the  relative  power  required  is  evidently  the  product  of  the 
factors  in  column  5  and  in  column  6,  for  it  is  represented  by  the  product  of  the  pres- 
sure into  the  velocity.  Upon  this  basis  column  8  has  been  calculated.  From  this  is 
evident  the  fact  that  the  work  performed  is  not  proportional  to  the  weight  of  the  air 
moved,  but  to  the  distance  through  which  the  resistance  is  overcome. 


WEIGHTS  OF  AIR,  VAPOR  OF  WATER,  AND  SATURATED  MIXTURES  OF  AIR  AND 

VAPOR 

At  Different  Temperatures  under  the  Ordinary  Atmospheric  Pressure  of  29.921  Inches  of  Mercury. 


Temperature, 
Fahrenheit. 

Volume  of 
Dry  Air. 
Volume  at 
32°  being 
1.000. 

Weight  of 
a  Cubic 
Foot  of 
Dry  Air 
in  Pounds. 

Elastic 
Force  of 
Vapor  in 
Inches  of 
Mercury 
(Reg- 
nault). 

Mixtures  of  Air  Saturated  with  Vapor. 

Cubic  Foot 
of  Vapor 
from  1  Lb. 
of  Water 
at  its  own 
Pressure 
in 
Column  4. 

Elastic 
Force  of 
the  Air  in 
the 
Mixture 
of  Air  and 
Vapor  in 
Inches  of 
Mercury. 

Weight  of  Cubic  Foot  of  the 
Mixture  of  Air  and  Vapor. 

Weight  of 
Vapor 
Mixed 
with  1  Lb. 
of  Air  in 
Pounds^ 

Weight  of 
Dry  Air 
Mixed 
with  1  Lb. 
of  Vapor 
in  Pounds. 

Weight  of 
the  Air  in 
Pounds. 

Weight  of 
the  Vapor 
in  Pounds. 

Total 
Weight  of 
Mixture 
in  Pounds. 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

0° 

.935 

.0864 

.044 

29.877 

.0863 

.000079 

.086379 

.00092 

1092.4 

12 

.960 

.0842 

.074 

29.849 

.0840 

.000130 

.084130 

.00155 

646.1 

22 

.980 

.0824 

.118 

29.803 

.0821 

.000202 

.082302 

.  00245 

406.4 

32 

1.000 

.0807 

.181 

29.740 

.0802 

.000304 

.080504 

.00379 

263.81 

3289 

42 

1.020 

.0791 

.267 

29.654 

.0784 

.000440 

.078840 

.00561 

178.18 

2252 

52 

1.041 

.0776 

.388 

29.533 

.0766 

.000627 

.077227 

.00819 

122.17 

1595 

62 

1.061 

.0761 

.556 

29.365 

.0747 

.000881 

.075581 

.01179 

84.79 

1135 

72 

1.082 

.0747 

.785 

29  .  136 

.0727 

.001221 

.073921 

.01680 

59.54 

819 

82 

1.102 

.0733 

1.092 

28.829 

.0706 

.001667 

.072267 

.02361 

42.35 

600 

92 

1.122 

.0720 

1.501 

28.420 

.0684 

.002250 

.070717 

.03289 

30.40 

444 

102 

1.143 

.0707 

2.036 

27.885 

.0659 

.002997 

.068897 

.04547 

21.98 

334 

112 

1.163 

.0694 

2.731 

27  .  190 

.0631 

.003946 

.067046 

.06253 

15.99 

253 

122 

1.184 

.0682 

3.621 

26.300 

.0599 

.005142 

.065042 

.08584 

11.65 

194 

132 

1.204 

.0671 

4.752 

25  .  169 

.0564 

.006639 

.063039 

.11771 

8.49 

151 

142 

1.224 

.0660 

6.165 

23.756 

.0524 

.008473 

.060873 

.16170 

6.18 

118 

152 

1.245 

.0649 

7.930 

21.991 

.0477 

.010716 

.058416 

.22465 

4.45 

93.3 

162 

1.265 

.0638 

10.099 

19.822 

.0423 

.013415 

.055715 

.31713 

3.15 

74.5 

172 

1.285 

.0628 

12.758 

17.163 

.0360 

.016682 

.052682 

.46338 

2.16 

59.2 

182 

1.306 

.0618 

15.960 

13.961 

.0288 

.020536 

.049336 

.71300 

1.402 

48.6 

192 

1.326 

.0609 

19.828 

10.093 

.0205 

.025142 

.045642 

1.22643 

.815 

39.8 

202 

1.347 

.0600 

24.450 

5.471 

.0109 

.030545 

.041445 

2.80230 

.357 

32.7 

212 

1.367 

.0591 

29.921 

0.000 

.0000 

.036820 

.036820 

Infinite 

.000 

27.1 

Other  things  equal,  and  friction  neglected,  the  power  required  to  drive  a  fan 
increases  as  the  cube  of  its  speed;  for  the  pressure  increases  as  its  square,  the  velocity 
obviously  increases  as  its  speed,  and  the  work  done  is  the  product  of  these  two  fac- 


156 


GAS   PRODUCERS 


tors.  Furthermore,  the  speed  remaining  constant,  the  volume  also  remains  constant, 
while  the  weight  of  air  moved  and  the  power  required  both  decrease  in  proportion 
to  the  density  of  the  air;  that  is,  inversely  as  its  absolute  temperature.  The  cause 
for  the  enormous  waste  of  energy  in  the  movement  of  air  by  a  chimney  is  due  to  the 
fact  that  the  energy  is  not  directly  applied,  as  with  a  fan,  but  that  the  air  movement 
is  secured  by  the  expenditure  of  heat  in  raising  the  temperature,  and  reducing  the 
density  of  the  gas,  so  that  gravity  may  act  to  produce  the  flow. 

VELOCITY,  VOLUME,  AND  HORSEPOWER  REQUIRED  WHEN  AIR  UNDER  GIVEN 
PRESSURE  IN  OUNCES  PER  SQUARE  INCH  IS  ALLOWED  TO  ESCAPE  INTO  THE 
ATMOSPHERE 


Pressure  in  Ounces. 
Per  Square  Inch. 

Velocity  of  Dry  Air  at  50°  Temperature  F. 
Escaping  into  the  Atmosphere  through  any 
Shaped  Orifice  in  any  Pipe  or  Reservoir  in 
which  the  Given  Pressure  is  Maintained. 

Volume  of  Air  in  Cubic 
Feet  which  may  be 
Discharged  in  One 
Minute  through  an 
Orifice  having  an 

Horsepower  Required 
to  Move  the  Given 
Volume  of  Air  Under 

Effective  Area  of 

the  Given  Conditions. 

Discharge  of 

In  Feet  per  Second. 

In  Feet  per  Minute. 

One  Square  Inch. 

i 

30.47 

1,828.4 

12.69 

0.00043 

1 

43.08 

2,585.0 

17.95 

0.00122 

1 

52.75 

3,165.1 

21.98 

0.00225 

* 

60.90 

3,653.8 

25.37 

0.00346 

f 

68.07 

4,084.0 

28.36 

0.00483 

1 

74.54 

4,472.6 

31.06 

0.00635 

1 

80.50 

4,829.7 

33.54 

0.00800 

1 

86.03 

5,161.7 

35.85 

0.0097S 

1* 

91.22 

5,473.4 

38.01 

0.01166 

H 

96.13 

5,768.0 

40.06 

0.01366 

it 

100.80 

6,047.9 

42.00 

0.01575 

H 

105.25 

6,315.2 

43.86 

0.01794 

if 

109.52 

6,571.3 

45.63 

0.02022 

if 

113.64 

6,817.6 

47.34 

0.02260 

14 

117.58 

7,055.0 

49.00 

0.02505 

2 

121.41 

7,284.4 

50.59 

0.02759 

2i 

125.11 

7,506.7 

52.13 

0.03021 

2* 

128.70 

7,722.2 

53.63 

0.03291 

2| 

132.20 

7,931.8 

55.08 

0.03568 

2J 

135.59 

8,135.7 

56.50 

0.03852 

2| 

138.91 

8,334.4 

57.88 

0.04144 

22 

142.14 

8,528.3 

59.22 

0.04442 

2| 

145.29 

8,717.6 

60.54 

0.04747 

3 

148.38 

8,902.8 

61.83 

0.05058 

3t 

151.40 

9,084.0 

63.08 

0.05376 

Si 

154.36 

9,261.5 

64.32 

0.05701 

31 

157.26 

9,435.4 

65.52 

0.06031 

84 

160.10 

9,606  .  1 

66.71 

0.063668 

31 

162.89 

9,773.3 

67.87 

0.06710 

3| 

165.63 

9,938.0 

69.01 

0.07058 

3* 

168.33 

10,099.6 

70.14 

0.07412 

MOVING   GASES 
VELOCITY,  VOLUME,  HORSEPOWER,  ETC.— Continued 


157 


Pressure. 

Velocity  per  Second. 

Velocity  per  Minute. 

Volume. 

Horsepower. 

4 

170.98 

10,258.6 

71.24 

0.07771 

4} 

176.15 

10,568.8 

73.39 

0.08507 

4i 

181.16 

10,869.5 

75.48 

0.09264 

4f 

186.03 

11,161.5 

77.51 

0.1004 

5 

190.76 

11,445.5 

79.48 

0.1084 

6J 

195.37 

11,722.0 

81.40 

0.1166 

5i 

199.86 

11,991.5 

83.24 

0.1249 

5! 

204.25 

12,254.8 

85.10 

0  .  1335 

6 

208.53 

12,511.9 

86.89 

0  .  1422 

»i 

216.82 

13,009.3 

90.34 

0  .  1602 

7 

224.77 

13,486.4 

93.66 

0.1788 

n 

232.42 

13.945,4 

96.84 

0.1981 

8 

239.80 

14,387.9 

99.92 

0.2180 

8J 

246.92 

14,815  4 

102.88 

0.2385 

9 

253.83 

15,229.6 

105.76 

0.2596 

9* 

260.52 

15,631.0 

108.55 

0.2812 

10 

267.00 

16,020.4 

111.25 

0.3034 

10£ 

273.32 

16,399.3 

113.88 

0.3261 

11 

279.70 

16,768.1 

116.45 

0.3493 

11* 

285.46 

17,127.6 

118.94 

0.3730 

12 

291.30 

17,478.2 

121.38 

0.3972 

12* 

297.01 

17,820.6 

123.75 

0.4219 

13 

302.59 

18,155.2 

126.06 

0.4470 

13J 

308.04 

18,482.4 

128.35 

0.4726 

14 

313.38 

18,802.7 

130.57 

0.4986 

14J 

318.61 

19,116.3 

132.75 

0.5250 

15 

323.73 

19,423.6 

134.89 

0.5518 

15J 

328.75 

19,725.0 

136.98 

0.5791 

16 

333.68 

20,020.7 

139.03 

0.6067 

16i 

338.51 

20,310.8 

141.05 

0.6347 

17 

343.26 

20,595.8 

143.03 

0.6631 

17* 

347.93 

20,875.8 

144.97 

0.6919 

18 

352.52 

21,151.0 

146.88 

0.7211 

18J 

357.03 

21,421.6 

148.76 

0.7506 

19 

361.46 

21,687.8 

150.61 

0.7804 

19J 

365.83 

21,949.7 

152.43 

0.8107 

20 

370.13 

22,207.5 

154.22 

0.8412 

158 


GAS   PRODUCERS 


HEIGHT  OF  WATER  COLUMN  IN  INCHES 

Corresponding  to  Various  Pressures  in  Ounces  per  Square  Inch 


Pres- 
sure in 
Ozs. 
per 

Sq.in. 

Decimal  Parts  of  an  Ounce. 

.0 

.1 

2 

.3 

.4 

.5 

.6 

7 

.8 

.9 

0 

0.17 

0.35 

0.52 

0.69 

0.87 

1.04 

1.21 

1.38 

1.56 

1 

1.73 

1.90 

2.08 

2.25 

2.42 

2.60 

2.77 

2.94 

3.11 

3.29 

2 

3.46 

3.63 

3.81 

3.98 

4.15 

4.33 

4.50 

4.67 

4.84 

5.01 

3 

5.19 

5.36 

5.54 

5.71 

5.88 

6.06 

6.23 

6.40 

6.57 

6.75 

4 

6.92 

7.09 

7.27 

7.44 

7.61 

7.79 

7.96 

8.13 

8.30 

8.48 

5 

8.65 

8.82 

9.00 

9.17 

9.34 

9.52 

9.69 

9.86 

10.03 

10.21 

6 

10.38 

10.55 

10.73 

10.90 

11.07 

11.26 

11.43 

11.60 

11.77 

11.95 

7 

12.11 

12.21 

12.46 

12.63 

12.80 

12.97 

13.15 

13.49 

13.32 

13.67 

8 

13.84 

14.01 

14.19 

14.36 

14.53 

14.71 

14.88 

15.05 

15.22 

15.40 

9 

15.57 

15.74 

15.92 

16.09 

16.26 

16.45 

16.62 

16.79 

16.96 

17.14 

PRESSURE  IN  OUNCES  PER  SQUARE  INCH 
Corresponding  to  Various  Heads  of  Water  in  Inches 


Head 


Decimal  Parts  of  an  Inch. 


in 
Inches 

.0 

1. 

.2 

.3 

.4 

.5 

.6 

.7 

.8 

9. 

0 

0.06 

0.12 

0.17 

0.23 

0  29 

0.35 

0.40 

0.46 

0.52 

1 

0.58 

0.63 

0.69 

0.75 

0.81 

0.87 

0.93 

0.98 

1.04 

1.09 

2 

1.16 

1.21 

1.27 

1.33 

1.39 

1.44 

1.50 

1.56 

1.62 

1.67 

3 

1.73 

1.79 

1.85 

1.91 

1.96 

2.02 

2.08 

2.14 

2.19 

2.25 

4 

2.31 

2.37 

2.42 

2.48 

2.54 

2.60 

2.66 

2.72 

2.77 

2.83 

5 

2.89 

2.94 

3.00 

3.06 

3.12 

3.18 

3.24 

3.29 

3.35 

3.41 

6 

3.47 

3.52 

3.58 

3.64 

3.70 

3.75 

3.81 

3.87 

3.92 

3.98 

7 

4.04 

4.10 

4.16 

4.22 

4.28 

4.33 

4.39 

4.45 

4.50 

4.56 

8 

4.62 

4.67 

4.73 

4.79 

4.85 

4.91 

4.97 

5.03 

5.08 

5.14 

9 

5.20 

5.26 

5.31 

5.37 

5.42 

5  48 

5.54 

5.60 

5.66 

5.72 

MOVING   GASES 


159 


AREAS  OF  ORIFICES 


Diameter  of 
Circle 
in  Inches. 

Area  of  Circle  in 
Square  Inches. 

Sides  of  Square  of 
Same  Area  in 
Square  Inches. 

Diameter  of 
Circle 
in  Inches. 

Area  of  Circle  in 
Square  Inches. 

Sides  of  Square  of 
Same  Area  in 
Square  Inches. 

1 

.785 

.89 

21 

346.36 

18.61 

u 

1.767 

1.33 

21* 

363.05 

19.05 

2 

3.142 

1.77 

22 

380.13 

19.50 

2* 

4.909 

2.22 

22* 

397.61 

19.94 

3 

7.069 

2.66 

23 

415.48 

20.38 

Si 

9.621 

3.10 

23* 

433.74 

20.83 

4 

12.566 

3.54 

24 

452.39 

21.27 

4} 

15.904 

3.99 

24* 

471.44 

21.71 

5 

19.635 

4.43 

25 

490.88 

22.16 

61 

23.758 

4.87 

25* 

510.71 

22.60 

6 

28.274 

5.32 

26 

530.93 

23.04 

6* 

33  .  183 

5.76 

26* 

551.55 

23.49 

7 

38.485 

6.20 

27 

572.56 

23.93 

7* 

44  .  179 

6.65 

27* 

593.96 

24.37 

8 

50.266 

7.09 

28 

615.75 

24.81 

8i 

56.745 

7.53 

28* 

637.94 

25.26 

9 

63.617 

7.98 

29 

660.52 

25.70 

9* 

70.882 

8.42 

29* 

683.49 

26.14 

10 

78.540 

8.86 

30 

706.86 

26.59 

10* 

86.590 

9.30 

30* 

730.62 

27.03 

11 

95.03 

9.75 

31 

754.77 

27.47 

11* 

103.87 

10.19 

31* 

779.31 

27.92 

12 

113.10 

10.63 

32 

804.25 

28.36 

m 

122.72 

11.08 

32* 

829.58 

28.80 

13 

132.73 

11.52 

33 

855.30 

29.25 

is* 

143  .  14 

11.96 

33* 

881.41 

29.69 

14 

153.94 

12.41 

34 

907.92 

30.13 

Mi 

165.13 

12.85 

34* 

934.82 

30.57 

15 

176.72 

13.29 

35 

962.11 

31.02 

15* 

188.69 

13.74 

35* 

989.80 

31.46 

16 

201.06 

14.18 

36 

1017.88 

31.90 

16* 

213.83 

14.64 

36* 

1046.35 

32.35 

17 

226.98 

15.07 

37 

1075.21 

32.79 

17* 

240.53 

15.51 

37* 

1104.47 

33.23 

18 

254.47 

15.95 

38 

1134.12 

33.68 

18i 

268.80 

16.40 

38* 

1164.16 

34.12 

19 

283.53 

16.84 

39 

1194.59 

34.56 

19* 

298.65 

17.28 

39* 

1225.42 

35.01 

20 

314.16 

17.72 

40 

1256.64 

35.45 

20* 

330.06 

18.17 

40* 

1288.25 

35.89 

160 


GAS    PRODUCERS 


REVOLUTIONS  OF  FAN-WHEEL  OF  GIVEN  DIAMETER  NECESSARY  TO  MAINTAIN  A 
GIVEN  PRESSURE  OVER  AN  AREA  WHICH  IS  WITHIN  THE  CAPACITY  OF  THE 
FAN. 


Diam.oi 
Fan- 
wheel  in 
Feet. 

Pressure  in  Ounces  per  Square  Inch. 

i 

i 

1 

i 

i 

3. 

i 

1 

H 

H 

H 

U 

If 

1 

582 

823 

1007 

1163 

1300 

1423 

1537 

1643 

1742 

1836 

1925 

2010 

2170 

H 

466 

658 

806 

930 

1040 

1139 

1230 

1314 

1394 

1469 

1540 

1608 

1736 

14 

388 

549 

672 

775 

867 

949 

1025 

1095 

1162 

1224 

1284 

1340 

1447 

if 

333 

470 

576 

665 

743 

813 

878 

938 

996 

1049 

1100 

1149 

1240 

2 

291 

411 

504 

582 

650 

712 

769 

822 

871 

918 

963 

1005 

1085 

2i 

259 

366 

448 

517 

578 

633 

683 

730 

774 

816 

856 

893 

964 

24 

233 

329 

403 

465 

520 

570 

615 

657 

697 

734 

770 

804 

868 

2| 

212 

300 

366 

423 

493 

518 

559 

597 

634 

668 

700 

731 

789 

3 

194 

274 

336 

388 

433 

475 

513 

548 

581 

612 

642 

670 

723 

34 

166 

235 

288 

332 

372 

407 

439 

469 

498 

525 

550 

574 

620 

4 

146 

206 

252 

291 

325 

356 

384 

411 

436 

459 

481 

502 

543 

44 

129 

183 

224 

258 

289 

316 

342 

365 

387 

408 

428 

447 

482 

5 

116. 

164 

202 

232 

260 

285 

308 

329 

349 

367 

385 

402 

434 

5* 

106 

149 

183 

211 

236 

259 

280 

299 

317 

334 

350 

366 

395 

6 

97 

137 

168 

194 

217 

238 

256 

274 

290 

306 

321 

335 

362 

64 

90 

126 

155 

179 

200 

219 

236 

253 

268 

282 

296 

309 

334 

7 

83 

117 

144 

166 

186 

203 

220 

235 

249 

262 

275 

287 

310 

74 

78 

110 

135 

155 

173 

190 

204 

219 

232 

245 

257 

268 

289 

8 

73 

103 

126 

146 

163 

178 

192 

205 

218 

230 

241 

251 

271 

84 

69 

97 

119 

137 

153 

167 

181 

194 

205 

216 

226 

236 

255 

9 

65 

92 

112 

129 

144 

158 

171 

183 

194 

204 

214 

223 

241 

»4 

61 

87 

106 

123 

137 

149 

162 

173 

183 

193 

203 

212 

228 

10 

58 

82 

101 

116 

130 

142 

154 

164 

174 

184 

193 

201 

217 

11 

53 

75 

92 

106 

118 

129 

140 

150 

158 

167 

175 

183 

197 

12 

49 

69 

84 

97 

108 

119 

128 

137 

145 

153 

160 

168 

181 

13 

45 

63 

78 

90 

100 

110 

116 

126 

130 

141 

148 

155 

167 

14 

42 

59 

72 

83 

93 

102 

110 

117 

124 

131 

138 

144 

155 

15 

39 

55 

67 

78 

87 

95 

102 

110 

116 

122 

128 

134 

145 

MOVING   GASES 


161 


REVOLUTIONS  OF  FAN-WHEEL  OF  GIVEN  DIAMETER  NECESSARY  TO  MAINTAIN  A 
GIVEN  PRESSURE  OVER  AN  AREA  WHICH  IS  WITHIN  THE  CAPACITY  OF  THE 
FAN— (Continued) 


Diam.ol 
Fan- 
wheel  in 
Feet. 

Pressure  in  Ounces  per  Square  Inch. 

2 

2i 

3 

3i 

4 

4i 

5 

5^ 

6 

6i 

7 

7* 

8 

1 

2319 

2590 

2834 

3058 

3265 

3460 

3643 

3817 

3992 

4141 

4293 

4439 

4580 

H 

1855 

2072 

2267 

2446 

2612 

2768 

2915 

3054 

3]  86 

3313 

3434 

3551 

3664 

14 

1546 

1727 

1889 

2039 

2178 

2307 

2129 

2545 

2655 

2761 

2862 

2960 

3053 

If 

1325 

1480 

1619 

1747 

1866 

1977 

2082 

2171 

2276 

2366 

2453 

2536 

2617 

2 

1159 

1295 

1417 

1529 

1633 

1730 

1822 

1909 

1996 

2070 

2146 

2219 

2289 

2i 

1030 

1151 

1259 

1359 

1451 

1538 

1619 

1696 

1770 

1840 

1908 

1973 

2035 

1\ 

928 

1036 

1134 

1223 

1306 

1384 

1457 

1527 

1593 

1656 

1717 

1776 

1832 

2J 

843 

942 

1030 

1112 

1188 

1258 

1325 

1388 

1448 

1506 

1561 

1614 

1665 

3 

773 

863 

945 

1019 

1089 

1153 

1215 

1272 

1328 

1380 

1431 

1480 

1527 

34 

662 

740 

810 

874 

933 

989 

1041 

1086 

1138 

1183 

1226 

1268 

1308 

4 

580 

647 

708 

764 

816 

865 

911 

954 

998 

1035 

1073 

1110 

1145 

44 

515 

575 

630 

679 

726 

769 

810 

848 

885 

920 

954 

986 

1018 

5 

464 

518 

567 

612 

653 

692 

729 

763 

796 

828 

859 

888 

916 

5i 

422 

471 

515 

556 

594 

629 

662 

694 

724 

753 

781 

807 

833 

6 

386 

432 

472 

510 

545 

577 

607 

636 

664 

690 

716 

740 

763 

64 

357 

398 

436 

470 

502 

532 

561 

587 

613 

637 

661 

683 

705 

7 

331 

370 

405 

437 

466 

494 

520 

543 

569 

592 

613 

634 

654 

7* 

309 

345 

378 

408 

435 

461 

486 

509 

531 

552 

572 

592 

611 

8 

290 

324 

354 

382 

408 

432 

455 

477 

499 

518 

537 

555 

572 

84 

273 

305 

333 

360 

384 

407 

429 

449 

469 

487 

505 

522 

539 

9 

258 

288 

315 

340 

363 

384 

405 

424 

443 

460 

477 

493 

509 

9i 

244 

273 

298 

322 

344 

364 

384 

402 

419 

436 

452 

467 

482 

10 

232 

259 

283 

306 

327 

346 

364 

382 

398 

414 

429 

444 

458 

11 

211 

235 

258 

278 

247 

315 

331 

347 

362 

376 

390 

.404 

416 

12 

193 

216 

236 

255 

272 

288 

304 

318 

332 

345 

358 

370 

382 

13 

178 

199 

218 

235 

251 

266 

280 

294 

306 

319 

330 

341 

352 

14 

165 

185 

202 

218 

233 

247 

260 

271 

284 

296 

307 

317 

327 

15 

155 

173 

189 

204 

218 

231 

243 

254 

266 

276 

286 

291 

305 

CHAPTER  VI 
SOLID     FUELS 

Coal. — Coal  is  a  remnant  of  the  flora  of  past  geological  periods;  consequently 
it  is  organic  matter  (chiefly  cellulose)  that  has  undergone  chemical  changes,  and  to 
which  mineral  impurities  have  been  added.  These  chemical  changes  are  indicated  in 
a  general  way  by  the  following  table  of  average  ultimate  analyses  of  cellulose,  wood, 
peat,  lignite,  bituminous  coal,  and  anthracite,  the  sulphur  and  ash  being  disregarded. 

ULTIMATE  ANALYSES  OF  FUELS 

Carbon  Hydrogen  Oxygen  Nitrogen 

Cellulose 44.4  6.2  49.4  0. 

Wood 50.  6.  43.  1. 

Peat 59.  6.  33.  2. 

Lignite 69.  5.5  25.  0.8 

Bituminous  coal.  ...  82.  5.  13.  0.8 

Anthracite  coal 95 .  2.5  2.5  trace 

These  figures  show  that  the  transformation  of  wood  to  anthracite  is  accompanied 
by  an  increase  in  the  carbon,  and  a  decrease  in  the  hydrogen  and  oxygen,  the  loss  in 
the  latter  element  being  the  more  pronounced.  As,  however,  these  analyses  show 
only  the  elementary  substances  that  go  to  compose  the  coal,  they  do  not  give  a  fair 
idea  of  the  complex  chemical  nature  of  the  coal  itself. 

The  ash  in  bituminous  coal  varies  from  3  to  15%  and  more,  but  for  a  better  com- 
parison of  the  coals  it  is  taken  uniformly  at  8%.  The  sulphur  varies  between  0.5 
and  2.5%  and  phosphorus  between  0.007  and  0.025%.  The  coal  gases  given  off 
during  destructive  distillation  are  inflammable  in  their  nature,  and  besides  water 
vapor  contain  tar,  ammonia,  cyanides,  benzol,  and  naphthalene. 

Classification  of  Coals. — Percy  classified  coal  into  three  varieties:  (1)  Non-caking, 
or  free-burning,  rich  in  oxygen;  (2)  caking;  (3)  non-caking,  rich  in  carbon.  This 
classification  was  based  on  the  chemical  composition  of  the  coals  and  therefore  on 
their  calorific  power.  Another  classification,  much  used  in  Europe,  divided  coal  not 
only  according  to  the  character  of  the  residue  left  after  dry  distillation,  but  also  accord- 
ing to  the  length  of  the  flame  produced  in  combustion.  Thus  Grimer  distinguished 
five  types  of  bituminous  coal,  as  follows: 

1.  Non-caking  coals  with  long  flames:  These  coals  which  most  closely  approach 
lignite  in  character,  yield  55  to  60%  of  pulverulent  coke,  the  evolution  of  volatile 

162 


SOLID    FUELS  163 

matter  giving  rise  to  a  long  smoky  flame.  In  composition  they  show  75  to  80%  C, 
4.5  to  5.5%  H,  and  15  to  19.5%  0  and  N,  the  ratio  of  the  oxygen  to  the  hydrogen  being 
3:1  to  4:1.  In  calorific  power  they  range  from  8000  to  8500  calories,  1  Ib.  of  coal 
being  capable  of  evaporating  from  8  to  10  Ibs.  of  water. 

2.  Caking,  long-flame  gas  coal:   The  coals  of  this  type  yield  60  to  68%  of  caked, 
but  very  friable  and  porous  coke,  and  32  to  40%,  of  volatile  matter,  of  which  17  to 
20%  is  gas.     In  composition  they  vary  from  80  to  85%  C,  5  to  5.8%  H,  and  10  to 
14.2%  0  and  N,  the  calorific  power  ranging  from  8500  to  8800  and  the  factor  of 
evaporation  from  8  to  9.7. 

3.  Bituminous  or  furnace  coal:    These  coals  burn  with  a  smoky  flame,  at  the 
same  time  softening  and  intumescing  in  the  fire.     They  yield  68  to  74%  of  caked  and 
swollen  coke  and  15  to  16%  of  gas.     In  composition  they  contain  from  84  to  89%  C, 
5  to  5.5%  H,  and  5.5  to  11%  O  and  N.     The  ratio  of  the   oxygen  to  the  hydrogen 
being  1:1.     Their  calorific  power  varies  from  8800  to  9300  and  their  factor  of  evapora- 
tion from  9.7  to  11. 

4.  Caking  coals  with  short  flame:    These  yield  74  to  82%  of  caked  and  very 
compact  coke  and  12  to  15%  of  gas.     They  contain  88  to  91%  C,  4.5  to  5.5%  H,  and 
5.5  to  6.5%  0  and  N,  the  ratio  of  the  oxygen  to  the  hydrogen  being  1:1.     Their 
calorific  power  varies  from  9300  to  9600  and  the  factor  of  evaporation  from  11  to  12. 

5.  Anthracite  coals:    These  yield  82  to  92%  of  pulverulent  or  fritted  coke  and 
12  to  8%  of  gas.     They  burn  with  a  short  flame.     They  contain  from  90  to  93%  C, 
4  to  4.5%  H,  and  3  to  5.5%  0  and  N,  the  ratio  of  the  oxygen  to  the  hydrogen  being 
0.5:1.     Their  calorific  power  varies  from  9200  to  9500,  and  their  evaporative  factor 
from  10.8  to  11.4.     These  coals  are  intermediate  between  the  bituminous  coals  and 
the  true  anthracite  of  the  United  States. 

The  reason  why  some  coals  should  have  the  caking  property  and  others  should 
not  is  not  clear,  non-caking  coals  being  often  of  very  similar  chemical  composition 
to  those  in  which  the  caking  property  is  highly  developed.  The  caking  coals  undergo 
an  incipient  fusion  or  softening  when  heated,  so  that  the  fragments  coalesce  and 
yield  a  compact  coke,  while  the  non-caking  coals  (also  call  free-burning)  preserve  their 
form,  producing  a  coke  wrhich  is  serviceable  only  when  made  from  large  pieces  of 
coal,  the  smaller  pieces  being  incoherent.  It  is  found  that  caking  coals  lose  their 
property  when  exposed  to  the  air  for  a  long  period  or  by  heating  to  about  300°  C., 
and  that  the  dust  or  slack  of  a  non-caking  coal  may  in  some  cases  be  converted  into 
a  coherent  coke  by  exposing  it  suddenly  to  a  very  high  temperature. 

The  distinction  between  long-flaming  and  short-flaming  coals  is  not  often  made 
in  the  United  States.  A  long-flaming  coal  is  simply  one  having  a  high  percentage  of 
volatile  matter,  which  gives  off  a  long  flame  when  burned  in  an  ordinary  furnace, 
because  of  the  difficulty  of  supplying  the  volatile  matter  with  sufficient  quantity  of 
hot  air  to  insure  its  complete  combustion.  The  manner  in  which  coal  is  burned  has 
a  great  effect  upon  the  flame.  Charcoal,  for  example,  if  burned  with  free  access  of 
air  merely  glow's;  but  if  burned  with  a  limited  supply  of  air  in  a  thick  bed,  wherein 
the  products  of  combustion  from  the  lower  part  will  pass  through  the  upper  part, 
carbon  monoxide  will  be  formed  and  will  burn  with  a  blue  flame.  The  same  phenom- 
enon can  be  produced  in  the  case  of  hard  coal  and  bituminous  coal  low  in  volatile 
matter,  and  is  taken  advantage  of  in  the  method  of  clinker  grate  firing,  wherein  a 


164  GAS   PRODUCERS 

thick  bed  of  coal  is  carried  on  the  grate  to  effect  an  incomplete  combustion  in  the 
fireplace  followed  by  a  secondary  combustion  of  the  carbon  monoxide  in  the  furnace, 
thus  elongating  the  flame  of  a  lean  coal.  This  verges  upon  gas  firing. 

Coals  are  also  classed  sometimes  as  "lean"  or  "fat,"  which  classification  corre- 
sponds more  or  less  to  "short-flaming"  and  "long-flaming."  All  of  the  above  classi- 
fications are  more  common  in  Europe  than  in  America. 

A  convenient  classification  of  coal  is  based  on  the  relative  percentages  of  fixed 
carbon  and  volatile  matter  contained  in  their  combustible  portion  determined  by 
proximate  analysis.  Such  a  classification  as  is  commonly  employed  in  the  United 
States  is  shown  in  the  following  table:* 


Class. 

Fixed  Carbon, 
Per  Cent. 

Volatile  Matter, 
Per  Cent. 

Heating  Value 
per  Pound  of 
Combustible, 
B.T.U. 

Relative  Value 
of  Combustible. 

Anthracite  

97.0  to  92.  5 
92.5  "  87.5 
87.5  "  75.0 
75.0  "  60.0 
65.0  "  50.0 
Under  50 

3.0to     7.5 
7.5  "  12.5 
12.5  "  25.0 
25.0  "  40.0 
35.0  "  50.0 
Over  50 

14,600 
14,800 
14,700 
15,000 
15,500 
16,000 
14,800 
15,200 
13,500 
14,800 
11,000 
13,500 

93 
94 
100 
95 
90 
77 

Semi-anthracite  

Semi-bituminous  

Eastern-bituminous  

Western-bituminous  

Lignite                         •                

The  classification  of  coal  is  usually  distinguished  according  to  the  following 
criteria:  Anthracite  usually  contains  more  than  ten  or  twelve  times  as  much  fixed 
carbon  as  volatile  combustible,  and  burns  with  practically  no  smoke. 

Bituminous  coal  usually  contains  less  than  three  or  four  times  as  much  fixed 
carbon  as  volatile  combustible  matter,  and  the  amount  of  the  former  usually  exceeds 
that  of  the  latter. 

Between  true  anthracite  and  true  bituminous  coal  two  classes  are  generally 
recognized:  Semi-anthracite,  which  contains  from  six  or  seven  to  ten  or  twelve  times 
as  much  fixed  carbon  as  volatile  combustible,  and  semi-bituminous,  which  contains 
from  three  or  four  to  six  or  seven  times  as  much  fixed  carbon  as  volatile  combustible. 
These  two  classes  differ  also  from  anthracite  in  being  softer,  in  this  respect  more  like 
bituminous  coal  and  in  burning  with  a  considerable  amount  of  flame,  but  do  not 
yield  as  much  smoke  as  bituminous  coal. 

Lignite  is  the  lower  grade  of  coal  in  which  some  traces  of  the  original  vegetable 
material  from  which  the  coal  is  formed  is  generally  still  to  be  recognized.  It  usually 
contains  from  ten  to  thirty  per  cent  of  moisture,  and  in  most  cases  contains  less 
fixed  carbon  than  volatile  combustible.  True  lignite  is  usually  brownish  in  color, 
although  the  so-called  black  lignites  resemble  bituminous  coal  in  their  color,  and  in 
other  of  their  properties.  Both  the  brown  and  the  black  lignites  slack  on  exposure 


*  William  Kent,  Steam  Boiler  Economy,  p.  42. 


SOLID   FUELS  165 

to  the  weather,  and  in  this  respect  are  easily  differentiated  from  the  higher  grade 
coals.  The  term  sub-bituminous  coal  has  recently  come  into  use  to  include  the 
black  lignite  and  some  of  the  lower  grades  of  the  coals  which  were  formerly  called 
bituminous. 

Peat  consists  of  slightly  consolidated  and  partly  decayed  vegetable  material 
which  has  not  been  consolidated  by  pressure  and  other  agencies  to  the  extent  that 
lignite  has.  The  original  vegetable  material  from  which  it  is  formed  is  always  much 
in  evidence,  and  neither  the  shiny  surfaces  nor  the  hardness  which  characterizes  both 
lignite  and  coal  have  been  developed.  An  equally  characteristic  distinction  is  that 
peat  occurs  as  a  surface  deposit,  while  coal  and  lignite  occur  interbedded  in  the 
rocks. 

Caking  and  Non-caking  Coals.— A  curious  instance,  as  cited  by  Fulton,  is  the 
fact  that  certain  coals  produced  in  Pennsylvania  and  Virginia  are  respectively  caking 
and  non-caking,  and  yet  possess  an  identical  analysis.  Butterfield  defines  caking 
and  non-caking  coals  as  follows: 

"Caking  coals  are  distinguished  by  softening  or  fusing  on  heating  and  yielding 
on  the  expulsion  of  volatile  matter  by  heat  a  carbonaceous  mass  of  cellular  structure 
presenting  no  evidence  of  the  form  or  shape  of  the  original  coal.  The  production 
of  this  mass  of  coke  does  not  appear  to  be  dependent  on  the  ultimate  composition  of 
the  coal,  but  rather  on  the  forms  of  combination  of  the  elements  existing  in  it,  which 
are  in  turn  determined  by  the  conditions  of  formation  and  geological  position. 

"Non-caking  coals  when  heated  until  all  volatile  matter  is  expelled,  yield  a  coke 
which  retains  the  form  of  the  coal,  or  crumbles  into  small  fragments.  No  fusion  or 
softening  of  the  coal  is  apparent,  and  the  coke  has  not  a  deeply  seamed  surface  or 
open  cellular  structure." 

Producer  Fuel. — Coking  or  caking  coal  is  most  unsuitable  for  gas-producer  work 
where  producers  are  of  the  shaft  type, — the  possible  exception  being  where  the  plant 
consists  of  many  units,  and  the  direction  of  the  gas  is  periodically  reversed.  Where, 
however,  such  coal  must  of  necessity  be  used,  it  should  be  mechanically  fed  (and 
mechanically  agitated)  as  the  labor  of  stoking  such  fuel  is  almost  prohibitive. 

In  addition  to  this,  the  tendency  of  coking  coal  to  agglomerate  materially  reduces 
the  carbon  surface  presented  for  combination.  Also  the  swelling  and  buckling  of  coal 
creates  channels,  with  a  consequently  porous  fuel  bed. 

Tapered  shaft  producers,  where  the  producer  linings  flare  as  they  arise  above  the 
grates  towards  the  top,  are  especially  impossible  with  coking  or  caking  fuels,  by  reason 
of  the  increased  difficulty  in  stoking. 

Where  "  run  of  mine  "  coal  is  used,  it  is  customary  to  break  the  coal  to  the  size 
of  a  fist. 

From  10  to  12%  of  ash  is  the  working  limit  of  the  average  shaft  producer  where 
sulphur  does  not  exceed  1  to  H%.  However,  the  gas  firing- capacity  of  the  producer 
is  considerably  reduced  thereby.  With  low  ash  a  maximum  of  2%  sulphur  may  be 
permitted,  experiments  by  the  Geological  Survey  having  reached  a  utilization  of  7%. 
This,  however,  should  be  avoided.  Ordinarily  1%  is  a  safe  working  limit.  The 
sulphur  usually  exists  in  the  form  of  iron  pyrites. 

Gas  Coal. — The  principal  gas-coal  fields  of  the  United  States  are  located  in  the 
Appalachian  coal  field  which  stretches  along  the  Appalachian  mountain  range  from 


166  GAS    PRODUCERS 

New  York  to  Alabama,  but  gas  coal  is  also  found  in  each  of  the  other  great  coal  fields, 
viz.:  the  Middle  in  Illinois,  Indiana,  and  Western  Kentucky;  the  Western  in  Mis- 
souri, Iowa,  Nebraska,  Kansas,  Arkansas,  and  the  Indian  Territory,  and  the  fields 
in  the  far  West,  the  limits  of  which  have  not  yet  been  clearly  defined  nor  their  resources 
fully  developed. 

Among  the  gas-coal  districts  of  the  Appalachian  field  the  Pittsburg  district  which 
lies  immediately  east  and  south  of  Pittsburg  on  the  Allegheny,  Monongahela,  and 
Youghioghenny  rivers  is  prominent.  The  coal  from  this  district  is  comparatively 
hard  and  dense,  so  that  it  can  be  transported  without  excessive  breakage,  and  yields 
a  good  amount  of  gas  of  good  quality  and  a  clean  hard  coke.  The  percentage  of  sul- 
phur contained  in  it  is  small,  being  usually  well  under  1%.  A  fair  gas  coal  is  also 
found  in  Jefferson  and  Beaver  counties,  Pennsylvania,  but  this  coal  is  not  quite  as 
good  as  that  from  the  main  body  of  the  Pittsburg  field. 

Another  important  field  is  the  West  Virginia  field  located  in  the  northern  part 
of  West  Virginia  along  the  banks  of  the  Monongahela  river.  The  coal  in  this  field 
is  very  similar  to  that  obtained  from  the  Pittsburg  district,  but  is  less  able  to  stand 
handling  without  disintegrating  and  is  apt  to  contain  more  sulphur,  although  some 
samples  show  very  well  in  this  respect. 

The  Kanawha  district,  also  in  West  Virginia,  extends  back  for  about  30  miles  on 
each  side  of  that  portion  of  the  Kanawha  river  between  Kanawha  falls  and  Charleston. 
The  coal  produced  here  differs  only  slightly  from  the  coals  mentioned  above,  except 
in  being  apt  to  contain  more  sulphur  than  is  found  in  the  coal  mined  in  the  West 
Virginia  district,  the  percentage  running  up  as  high  as  1.5%  in  some  samples,  although 
as  low  as  0.6%  in  others.  Cannel  coal  is  also  found  in  paying  quantities  in  this 
district. 

Kentucky  possesses  a  little  gas  coal,  but  hardly  enough  to  be  taken  into  consid- 
eration, if  it  were  not  for  its  large  deposits  of  cannel  coals.  The  best  known  of  these 
is  the  Breckenridge,  which  besides  giving  off  a  large  amount  of  rich  volatile  matter 
yields  also  a  fairly  good  coke  which  can  be  mixed  to  a  proportion  of  10%  with  the 
coke  from  ordinary  gas  coal  without  depreciating  the  latter. 

In  Tennessee  good  gas  coal  is  found  in  Scott  and  Anderson  counties,  while  in 
Campbell  an  excellent  cannel  coal  is  mined  which  is  similar  to  the  Breckenridge  and 
is  known  as  Jellico  cannel.  The  gas  coal  is  a  clean  hard  coal,  fully  equal  in  all 
respects  to  that  obtained  from  the  Pittsburg  district. 

In  Alabama  there  are  three  coal  fields,  the  Cahaba,  the  Coosa,  and  the  Warrior, 
in  each  of  which  some  coal  is  found  which  can  be  used  as  gas  coal,  but  the  best  coal 
for  this  purpose  comes  from  the  Corona  seam  in  Walker  county.  This  coal  is  clean 
and  hard  enough  to  bear  handling  well. 

Although  Ohio,  Indiana,  and  Illinois  produce  coal  that  is  used  locally  for  gas 
making,  they  cannot  be  considered  as  gas-coal  districts,  since  the  coal  is  only  used 
for  this  purpose  when  the  gas  works  are  practically  over  the  mines,  and  Pennsylvania 
coal  is  in  demand  throughout  these  states  for  use  in  preference  to  the  local  coal. 

In  Kansas  the  Cherokee  field  produces  a  gas  coal  that  is  good  in  every  respect, 
except  that  the  amount  of  sulphur  contained  in  it,  and  this  runs  from  2.5  to  5%  and 
even  as  high  as  8%  in  some  samples. 

The  Choctaw  country  in  Indian  Territory  yields  a  coal  which  is  clean  and  hard, 


SOLID   FUELS 


167 


stands  handling,  and  produces  a  good  coke.  It  closely  resembles  the  Pennsylvania 
coals  although  it  contains  more  sulphur  and  ash  than  the  latter,  the  percentage  of 
sulphur  being  a  little  over  1%. 

The  Trinidad  field  in  Colorado  also  furnishes  a  clean  bright  coal  that  is  low  in 
sulphur  and  is  said  to  give  a  good  yield  of  good  quality  gas  and  from  60  to  70%  of 
compact  coke. 

On  the  Pacific  coast  the  South  Prairie  and  Roslyn  fields  give  a  coal  from  which  a 
fair  amount  of  fairly  good  quality  gas  can  be  obtained  and  which  is  low  in  sulphur, 
but  produces  a  soft  friable  and  comparatively  poor  coke. 

The  principal  gas-coal  fields  in  Canada  lie  on  Glace  Bay  and  Cow  Bay  in  Cape 
Breton.  These  provincial  coals  were  formerly  used  quite  extensively  by  gas  works 
situated  on  the  Atlantic  coast  of  the  United  States.  They  yield  a  good  amount  of 
gas  of  a  quality  better  than  average,  but  they  disintegrate  easily,  contain  a  large 
amount  of  sulphur  and  are  very  susceptible  to  spontaneous  combustion.  At  the 
present  time  their  use  has  been  practically  abandoned  in  the  gas  works  of  the  United 
States. 

The  average  analysis  of  some  of  the  coals  mentioned  above  follow: 


ANALYSES  OF  GAS  COALS 


District. 

Volatile  Matter. 

Fixed  Carbon. 

Ash. 

Sulphur. 

Pittsburg  

35  to  40 

54  to  58 

3  to  5 

0  6 

West  Virginia  

35  "  40 

53  "  57 

4  "  7 

1  0 

Kanawha  

34  "  40 

55  "  62 

2  "  4 

0  6  to  1  5 

Breckenridge  cannel  

47 

42 

10 

0  6 

Tennessee  gas  coal  

36  to  39 

56  to  60 

1  8  to  3 

0  8 

Jellico  cannel  

50 

35 

14 

1  7 

Alabama  Corona  seam  

34  to  41 

50  to  59 

7  to  9 

0  7 

Kansas  Cherokee  

37 

52 

9 

2  5  to  8 

Indian  Territory  

37  to  40 

51  to  55 

4  to  7 

0  9  to  1  3 

Roslyn  Washington  

28 

61 

9 

0  1 

Colorado  Trinidad  

33  to  37 

51  to  57 

9 

0  7  to  1  4 

Cape  Breton  

35 

53 

5  5 

3 

The  anthracite  coal  production  of  the  United  States  is  confined  to  Pennsylvania, 
with  small  beds  in  Colorado,  Rhode  Island,  and  New  Mexico.  Bituminous  coal  must 
be  stored  in  piles  not  more  than  35  ft.  high,  owing  to  the  danger  of  spontaneous  com- 
bustion. Anthracite  is  stored  much  deeper  in  piles  and  can  be  handled  with  bucket 
conveyors  and  other  similar  implements. 

Tar  Yield  from  Gas  Coal. — When  an  ordinary  gas  coal  is  subject  to  destructive 
distillation,  the  volume  of  gas,  its  heating  and  illuminating  value,  and  also  the  quan- 
tity and  quality  of  the  tar  undergo  great  changes,  according  to  the  temperature  at 
which  the  distillation  is  carried  out,  and  the  following  table  shows  the  average  results 
that  are  obtained  with  a  good  sample  of  gas  coal.  The  term  "  average  results  "  is 
used,  as  variations  in  the  coal  employed  introduced  alterations  in  the  results,  although 
they  will  all  follow  similar  lines: 


168  GAS   PRODUCERS 

YIELD  OF  GAS  AND  TAR  PER  LONG  TON  OF  COAL  CARBONIZED 


Temperature  of  Distillation. 

Volume  of  Gas, 
Cubic  Feet. 

Tar,  Gallons. 

Specific  Gravity  of 
Tar. 

Degrees  C. 

Degrees  F. 

900 

1652 

11,000 

9 

1.200 

800 

1472 

10,000 

12 

1.170 

700 

1292 

9,000 

15 

1.140 

600 

1112 

7,750 

18 

1.115 

500 

932 

6,400 

21 

1.087 

400 

752 

5,000 

23 

1.020 

Coal  Analysis. — The  method  of  determining  the  coking  qualities  of  a  coal  is  by 
actual  experiment.     The  usual  form  of  laboratory  test  is  known  as  the  crucible  test. 

It  consists  in  placing  a  known  weight  of  dried  coal 
in  a  covered  platinum  crucible  and  heating  it  till 
all  the  volatile  matter  is  driven  off,  combustion  of 
the  residue  being  prevented  by  the  close-fitting  lid 
which  keeps  out  the  air.  The  nature  of  the  residue 
indicates  approximately  the  coking  properties  of 
the  coal,  and  its  weight  the  approximate  yield  of 
coke  to  be  expected,  while  the  loss  of  weight  corres- 
ponds to  the  "volatile"  matter.  This  process  cor- 
responds on  a  small  scale  with  the  treatment  of 
coal  in  the  coke  oven.  The  re-heating  of  the 
coke  in  the  crucible  without  the  lid  until  all  the 
carbon  is  consumed,  leaves  the  ash  as  the  sole 
residue,  the  loss  of  weight  in  this  case  indicating 
the  ''fixed  carbon."  This  crucible  test,  together 
with  separate  determinations  of  sulphur  and  phos- 
FIG.  95— Crucible  Proximate  phorus,  are  the  usual  tests  made  to  ascertain  the 
Coal  Test.  character  of  a  coal  under  investigation.  Such  tests 

of    the    coking    coals    of    this    country,    ranging    from 
those  of  low  to  those  of  higher  volatile  matter,  would  be  as  follows: 


CRUCIBLE  TESTS  OF  BITUMINOUS  COALS  AND  COKE 


Kind  of  coal. 

Low  volatile 
coal 

Coking  coals 

High  volatile  or  gas  coal 

Behavior  when  heated  .  . 
Character  of  coke  

Expanding 

Very  dense 
and  firm 

Neutral 

Dense  and 
firm 

Moderately 
shrinking 
Larger  cells 
but  firm 

Strongly 
shrinking 
Spongy  and 
brittle 

Typical  blast 
furnace  coke 

Crucible  Test  : 
Volatile  matter  
Fixed  carbon  
Ash  

18.0 
74.0 
8.0 

25.0 
67.0 

8.0 

32.0 
60.0 
8.0 

38.0 
54.0 
8.0 

1.5 

87.5 
11.0 

SOLID   FUELS 


169 


Sulphur. — Coal  possessing  more  than  0.5%  of  sulphur  content  is  not  advocated 
for  use  in  producers,  especially  for  power  work,  there  being  a  tendency  to  form  sul- 
phurous oxide  and  sulphuric  acid,  both  of  which  attack  the  packing  of  the  pistons 
and  the  stuffing  boxes  of  engines. 

It  has  also  been  shown,  where  gas  produced  from  coal  of  a  highly  sulphur  quality 
and  used  unpurified  for  cooking,  that  the  results  have  been  detrimental  to  both  the 
food  and  products  of  combustion. 

Coal  containing  a  high  content  of  sulphur  may  frequently  be  crushed  and 
washed  with  a  considerable  degree  of  purification.  This  is  particularly  so  when  the 
pyrite  occurs  free  in  the  seams  of  the  coal. 

ANALYSES  OF  ASH 
From  Carpenter's  Engineering 


Specific 
Gravity. 

Silica. 

Alumina. 

Oxide  of 
Iron. 

Lime. 

Magnesia. 

Loss. 

Acids, 
S.  &P. 

Pennsylvania  anthracite. 
Pennsylvania  bituminous 
Welsh  anthracite  

1.559 
1.372 
1.32 

45.6 
76.0 
40.0 

42.75 
21.00 
44.8 

9.43 
2.60 

1.41 
12  0 

0.33 
trace 

0.48 
0.40 

2   97 

Scotch  bituminous  
Lignite.  .  . 

1.26 
1  27 

37.6 
19  3 

52.0 
11  6 

5  8 

3.7 
23  7 

1.1 

2  6 

5.02 
33  8 

Calculating  Heat  Value.  —  A  rapid  and  convenient  method  for  the  determination 
of  the  calorific  power  of  coal  to  within  1%  (2%  for  lignites)  is  given  by  Goutal  in 
Stahl  und  Eisen. 

Moisture  is  first  removed  from  a  small  sample  of  the  coal  by  drying  in  a  crucible 
at  about  240°  F.  The  volatile  matter  and  ash  are  determined  by  coking  in  a  white- 
hot  crucible.  If  C  be  the  resulting  percentage  of  carbon,  and  V  the  percentage  of 
volatile  matter,  the  proportion  X  of  volatile  to  total  combustible  is  given  by  the 
equation 


The  calorific  power  Q  of  the  coal  is  then  found  by  the  equation 


wherein  a  is  found  from  the  following  table  of  values  in  terms  of  X: 


X, 

Per  Cent. 

a. 

B.T.U. 

X, 

Per  Cent. 

a, 
B.T.U. 

x, 

Per  Cent. 

a, 
B.T.U. 

X, 
Per  Cent. 

a, 
B.T.U. 

5 

161 

14 

216 

23 

189 

32 

174 

6 

256 

15 

211 

24 

187 

33 

173 

7 

250 

16 

207 

25 

185 

34 

171 

8 

245 

17 

204 

26 

184 

35 

169 

9 

239 

18 

202 

27 

182 

36 

164 

10 

234 

19 

198 

28 

180 

37 

158.5 

11 

229 

20 

196 

29 

178 

38 

153 

12 

223 

21 

194 

30 

176 

39 

148 

13 

220 

22 

193 

31 

175 

40 

144 

170 


GAS   PRODUCERS 


Moisture  in  Boiler  Coal. — In  the  Sturtevant  trade  handbook  entitled  "Mechanical 
Draft,"  is  treated  the  subject  of  the  influence  of  moisture  in  coal.  Moisture  in  coal 
is  an  exceedingly  variable  quantity,  depending  upon  the  character  of  the  coal,  its 
temperature,  and  its  previous  exposure  to  the  atmosphere.  Under  ordinary  condi- 
tions its  percentage  varies  from  1  to  5%.  Whatever  its  amount,  it  must  all  be  raised 
to  212°,  evaporated  into  steam,  and  the  steam  raised  to  the  temperature  of  the  escap- 
ing gases.  It  therefore  has  an  important  influence  upon  the  theoretical  heat  value 
of  a  given  coal.  Thus,  if  one  coal  was  composed  of  80%  carbon,  15%  ash,  and  5% 
water,  and  another  consisted  of  the  same  proportion  of  carbon,  with  5%  ash  and  15% 
water,  the  theoretical  calorific  value,  viz.,  11,720  B.T.U.,  would  be  the  same,  being 
directly  dependent  upon  the  amount  of  carbon.  But  in  the  first  case  the  available 
heat  (neglecting  losses  not  due  to  water)  would  be  10,600  B.T.U.,  while  in  the  second 
it  would  be  10,488  B.T.U.  if  the  waste  gases  were  assumed  to  escape  at  500°. 

COAL  ANALYSIS 
COALS  SUCCESSFULLY  GASIFIED  IN  LOOMIS-PETTIBONE  GAS  PRODUCERS 


Name  of  Mine. 

Carbon, 
Fixed. 

Volatile. 

Sulphur. 

Water. 

Ash. 

B.T.U. 

Big  Muddy  111. 

53.9 

28.3 

1.0 

7.4 

10.5 

13,757 

<  i         1  1                             i  i 

52.7 

30.1 

1.2 

6.1 

9.2 

13,613 

Brazil.  ...              .  .        Ind. 

50.3 

34.5 

1.39 

8.68 

6.3 

14,542 

Cumberland  .  .  .            Md. 

80.7 

13.0 

1.25 

5.0 

16,321 

George's  Creek.  .  .  . 
Cambridge                      Ohio 

50  3 

37.8 

3.01 

2.43 

6.1 
9.4 

15,140 
14,474 

Youghioghermy.  .  .         Pa. 
New  River  W.  Va. 

54,7 

32.6 

5.9 
0.6 

13,752 
14,359 

(tit                           it 

5.7 

14,601 

Pocahontas  

73.6 

18.3 

0.57 

0.80 

7.2 

15,682 

it                               it 

75.1 

18.6 

0.57 

0.63 

5.6 

15,718 

if                               it 

73.6 

17.1 

0.60 

0.75 

8.6 

15,730 

Webster  Pa. 

Shawmut 

Cerrilos                          N.  M. 

Barotoran                       Mex. 

66  8 

11.5 

21.7 

«                                                a 

63.2 

10.8 

26.0 

ft                                               n 

59.8 

11.7 

28.5 

it                                               it 

63.0 

12.1 

24.9 

The  makers  of  this  producer  are  willing  to  handle  any  coal  of  a  non-coking  char- 
acter that  contains  volatile  42%  and  less,  the  ash  effects  only  the  capacity.  When 
ash  above  12%  is  gotten,  its  use  is  questioned. 

The  same  guarantee  of  fuel  consumption  is  made  for  the  Loomis-Pettibone  system 
or  the  suction  producer  system. 

Clinkering  Properties  of  Coal. — It  is  generally  agreed  that  clinkering  is  due  to 
the  high  fuel  bed  temperaturres  on  such  of  the  mineral  constituents  in  the  ash  as  will 
form  a  fusible  mixture.  It  must  be  remembered  that  the  fineness  of  subdivision  and 
the  distribution  of  the  minerals  through  the  coal  are  probably  as  important  as  the 
temperature  and  chemical  composition.  Thus  it  is  that  "  sulphur  "  (pyrites)  in  the 


SOLID  FUELS  171 

form  of  little  balls  is  nearly  harmless;  in  the  form  of  veins  or  layers  it  is  liable  to 
cause  trouble;  but  in  the  form  of  "  black  sulphur/'  so  finely  distributed  as  to  be 
invisible,  it  is  most  troublesome. 

Sulphur  is  an  undesirable  element  in  coal.  It  generally  occurs  in  combination 
with  iron,  as  iron  pyrites,  and  in  combination  with  calcium,  as  calcium  sulphate  or 
gypsum.  The  calcium  sulphate  occurs  in  smooth,  thin,  white  flakes,  more  or  less 
transparent.  Of  the  two  sulphur  compounds  the  pyrites  is  generally  contained  in 
larger  amount  in  the  coal  and  is  harmful,  as  it  increases  the  tendency  of  the  coal  to 
clinker. 

The  impression  is  general  that  iron  causes  clinkering.  The  results  of  tests  made 
at  the  fuel-testing  plant  of  the  U.  S.  Geological  Survey  at  Pittsburg  confirm  this 
impression,  as  the  percentage  of  iron  in  dry  coal  increases  in  general  with  the  clinker. 
Nevertheless,  iron  is  only  one  of -the  causes  of  clinkering,  and  its  presence  in  consider- 
able quantity  does  not  necessarily  mean  that  a  coal  will  clinker  badly. 

The  exact  and  scientific  reasons  why  certain  coals  clinker  has  not  thoroughly 
been  determined. 

Coals  which  give  a  very  heavy  clinker  which  cannot  readily  be  broken  up  by  the 
use  of  steam  may  be  burned  satisfactorily  by  spreading  over  the  grate  bars  a  thin 
layer  of  limestone  before  the  furnace  is  put  in  commission  for  its  daily  run.  The  lime- 
stone combines  with  the  clinker  with  the  result  that  the  latter  does  not  adhere  to  the 
grate  bars. 

Purchasing  of  Coal. — As  it  has  elsewhere  been  stated,  the  difficulty  in  making  a 
complete  analysis  of  coal  is  so  great  and  such  skill  and  constant  practice  is  required, 
that  in  case  of  smaller  plants  and  plants  accessible  to  large  laboratories,  it  is  as  a 
rule  more  economical  to  send  samples  for  analysis  to  laboratories  which  are  properly 
equipped,  than  attempt  to  make  any  absolute  determinations. 

However,  calorimetric  tests  may  and  should  be  made  as  a  continuous  practice, 
and,  by  way  of  analogous  comparison  of  coal  purchased  and  used,  may  be  checked 
to  a  fair  degree  of  accuracy. 

The  question  of  transportation  to  some  extent  effects  the  economic  considera- 
tion of  the  coal  to  be  bought;  that  is  to  say,  where  most  of  the  total  cost  consists  in 
freight,  handling,  or  transportation,  it  might  prove  an  economy  to  pay  considerable 
more  for  the  initial  fuel,  inasmuch  as  it  costs  as  much  to  transport  ash,  moisture, 
or  neutral  content  as  combustible  matter,  and  under  these  circumstances  it  is  better 
to  buy  combustible  matter  in  a  more  condensed  and  compact  form. 

It  should  ever  be  kept  in  mind  that  the  purchase  is  that  of  thermal  units  and 
the  question  is  that  of  delivery  of  thermal  units  to  the  furnace,  the  greatest  number 
at  the  least  cost. 

The  following  interesting  matter  is  abstracted  from  Bulletin  No.  339  of  the  U. 
S.  Geological  Survey: 

"The  aim  in  the  purchase  of  coal  for  any  power  plant  should  be  to  obtain  a  fuel 
which  will  produce  a  horsepower  for  the  least  cost,  all  things  being  considered,  such 
as  the  equipment,  the  price  of  coal,  and  the  cost  of  labor  and  repairs.  Experiments 
have  been  made  which  seem  to  indicate  that  almost  any  fuel  may  be  burned  with 
reasonble  efficiency  in  a  properly  designed  apparatus.  The  recognized  requirements 
are  as  follows: 


172  GAS   PRODUCERS 

"A  supply  of  fuel  fed  to  the  furnace  as  uniformly  and  continuously  as  possible. 
An  air  supply  slightly  in  excess  of  the  theoretical  amount  required  for  complete  com- 
bustion. 

"A  sufficiently  high  temperature  to  ignite  the  gases  which  are  driven  off  from 
the  fuel.  A  complete  mixture  of  these  gases  with  the  air  supplied  before  they  reach 
the  cooling  surface,  such  as  the  shell  or  tubes  of  a  boiler." 

Some  of  the  factors  which  may  influence  the  commercial  results  obtained  in  a 
boiler  are  the  cost  of  the  coal,  as  determined  by  price  and  heating  value;  care  in 
firing;  design  of  the  furnace  and  boiler  setting;  size  of  grate,  etc.;  formation  of  exces- 
sive amounts  of  clinker  and  ash;  draft  available;  size  of  coal  (uniformity  of  size  is 
desirable). 

The  value  of  a  coal  is  indicated  by  the  number  of  heat  units  it  contains.  This 
heating  value  is  expressed  in  terms  of  British  thermal  units  per  pound  of  coal,  and  is 
determined  by  means  of  a  special  apparatus  called  a  calorimeter. 

When  coal  is  mined  it  contains  moisture  to  a  greater  or  less  extent.  It  is  exposed 
to  the  air  in  shipment  and  is  either  dried  out  or  drenched  by  rain.  The  moisture  in 
the  coal  delivered  is  worthless  to  the  purchaser  and  really  costs  him  a  considerable 
amount  in  freight  and  cartage,  and  in  the  loss  of  the  heat  absorbed  during  its  evap- 
oration in  the  furnace.  If  all  coal  had  the  same  proportion  of  moisture,  or  if  the 
moisture  in  coal  delivered  by  a  given  dealer  was  constant  in  amount,  the  purchasers' 
problem,  so  far  as  this  factor  is  concerned,  would  be  simplified.  Under  present  con- 
ditions the  moisture  is  an  important  element  in  the  valuation  of  a  ton  of  coal.  It  is 
evidently  necessary  to  consider  the  coal  just  as  it  is  received  in  order  to  determine 
its  value  to  the  consumer,  but  chemical  reports  should  be  made  on  the  basis  of  both 
the  "dry  coal"  and  the  "coal  as  received."  The  dry  coal  basis  is  convenient  for 
comparing  several  coals  in  regard  to  the  relation  of  each  element  to  the  others;  this 
is  important,  because  the  moisture  in  the  same  coal  varies  from  day  to  day.  The 
dry  coal  basis  is  also  convenient  for  comparing  the  performance  of  boilers  when  burn- 
ing the  same  or  similar  coals.  Of  several  coals  having  a  similar  composition,  the  one 
which  has  the  least  moisture  and  the  least  ash  will  generate  the  most  steam  when 
burned  under  a  boiler. 

Ash  is  made  up  of  earthy  matter  and  other  impurities  which  will  not  burn.  In 
commercial  coals  its  proportion  may  range  from  4  to  25%.  Coals  containing  small 
percentages  of  ash  are  most  valuable,  not  only  because  of  their  correspondingly  higher 
heating  capacity,  but  because  there  is  less  resistance  to  the  free  and  uniform  distri- 
bution of  air  through  the  bed  of  coal.  The  labor  and  cost  of  managing  the  fires  and 
of  handling  the  ashes  are  also  correspondingly  less  and  are  items  to  be  considered  in 
the  choice  of  a  coal.  With  the  ordinary  furnace  equipment  there  may  be  a  consid- 
erable loss  of  efficiency  and  capacity  through  a  large  percentage  of  ash.  It  has  been 
found  that  with  some  kinds  of  equipment,  as  the  ash  increases,  there  is  a  decided  drop 
in  both  efficiency  and  capacity.  In  some  experiments,  made  to  determine  the  influ- 
ence of  excessive  amounts  of  ash,  coal  containing  as  high  as  40%  would  generate  no 
steam  when  fired  on  a  chain  grate,  and  therefore  the  efficiency  and  capacity  of  the 
plant  would  be  zero.  Such  coal  would  not  only  be  worthless,  but  involve  a  direct 
expense  due  to  the  cost  of  handling  it.  Whether  the  result  would  be  similar  with 
equipment  other  than  a  chain  grate  has  not  yet  been  determined.  However,  coals 


SOLID   FUELS  173 

so  high  in  ash  that  they  are  unsuited  to  boiler  furnaces  can  be  utilized  in  gas  pro- 
ducers. 

The  volatile  part  of  coal,  as  shown  by  the  analysis,  may  in  some  coals  be  all  com- 
bustible, but  it  generally  contains  some  inert  matter.  This  varies  in  different  coal 
deposits  and  makes  it  impossible  to  determine  the  heating  value  of  the  coal  from  the 
approximate  analysis  alone. 

Moreover  not  all  coals  having  the  same  proportion  of  volatile  matter  behave 
alike  in  the  furnace.  It  is  important  to  know  both  the  chemical  composition  and  the 
British  thermal  units  in  order  to  determine  the  value  of  one  coal  as  compared  with 
another  for  the  same  purpose. 

Of  two  coals  of  different  character,  the  one  which  contains  the  higher  proportion 
of  fixed  carbon  is  most  easily  burned  so  as  to  give  the  maximum  efficiency.  How- 
ever, if  the  coal  containing  the  higher  volatile  matter  is  properly  burned  in  a  suitably 
designed  furnace,  it  may  be  made  equally  efficient. 

A.  Berthold  shows  that,  in  the  ordinary  method  of  determining  the  volatile  matter 
in  coal  by  heating  in  a  platinum  crucible,  both  the  dimensions  and  weight  of  the 
crucible  employed  affect  the  results  to  a  very  considerable  extent.  For  instance, 
using  three  different  crucibles  ranging  in  diameter  at  the  mouth  from  33  to  40  mm., 
in  height  from  38  to  46  mm.,  and  in  weight  from  20.1  to  27.6  gms.  he  found  that 
the  same  coal,  heated  in  a  flame  varying  in  height  from  9  to  29  cm.,  gave  from  80  to 
86.82%  yield  of  coke.  He  concludes  that,  for  estimating  coal  for  gas-works  use,  a 
comparatively  small  crucible  is  the  best,  and  suggests  that  it  shall  be  19  mm.  wide 
at  the  base,  33  mm.  wide  at  the  top,  38  mm.  high,  and  weigh  approximately  20  gms. 
It  should  be  supported  3  cm.  above  the  top  of  the  Bunsen  burner  of  wThich  the  flame, 
when  burning  freely,  should  be  at  least  18  cm.  in  height.  Such  conditions  give  results 
as  nearly  as  may  be  in  agreement  with  those  afforded  in  carbonization  in  gas  works. 
For  coke  oven  valuations  he  prefers  to  use  a  larger  and  heavier  crucible. 

Sulphur  may  be  present  in  the  free  state,  or  as  is  more  commonly  the  case,  in 
combination  with  iron  and  other  elements.  Other  impurities  with  sulphur  often 
form  a  clinker  which  shuts  out  the  air  and  increases  the  labor  of  handling  the  fur- 
naces. It  is  possible,  however,  to  burn  coals  containing  up  to  5%  of  sulphur  without 
particular  difficulty  from  clinkers.  Clinker  may  be  due  to  other  causes  than  sulphur, 
as  any  constituents  of  the  ash  which  are  easily  fusible  may  produce  it.  There  is  need 
of  further  investigation  to  determine  the  influence  of  sulphur  and  the  elements  which 
comprise  the  ash  on  furnace  fires  and  combustion. 

The  results  of  tests  tend  to  show  that,  other  conditions  being  equal,  coals  of 
similar  composition  are  of  value  in  proportion  to  the  British  thermal  units  in  the  coal 
as  received — a  basis  on  which,  indeed,  all  coals  may  be  valued  approximately.  It 
should  be  remembered,  however,  that  the  value  of  a  coal  for  any  particular  plant  is 
influenced  by  the  fact  that  all  furnaces  are  not  equally  suitable  for  burning  the  many 
grades  of  coal.  Aside  from  this  factor,  coals  may  be  compared  in  terms  of  the  British 
thermal  units  obtained  for  one  cent  or  on  the  cost  per  million  heat  units. 

Mine  samples  when  properly  taken  indicate  the  general  character  of  the  coal  and 
enable  one  to  judge  of  its  probable  value  for  any  definite  purpose.  Samples  taken 
from  the  cars  should  not  be  limited  to  a  few  shovelsful  of  coal  from  the  top  of  the  car, 
because  the  heavier  pieces  gradually  work  down  toward  the  bottom.  Some  samples 


174 


GAS    PRODUCERS 


taken  at  the  bottom  of  a  car  have  shown  as  much  as  8%  more  ash  than  the  coal  at 
the  top.  The  moisture  also  may  very  from  top  to  bottom,  depending  on  the  weather. 
The  only  way  to  get  a  fair  sample  is  to  take  a  number  of  shovelsful  of  coal  from 
various  points  in  the  car,  so  as  to  procure  a  representative  portion  of  the  coal  from 
top  to  bottom  and  from  end  to  end. 

Bituminous  coal  when  exposed  to  the  air  gradually  depreciates  in  heating  value 
owing  to  losses  of  volatile  matter,  but  aside  from  this  loss  there  should  be  the  same 
total  number  of  heat  units  in  a  car  of  coal  when  it  reaches  its  destination  as  when  it 
started.  If  rain  falls  on  the  coal  it  will  become  heavier  and  a  greater  number  of 
pounds  will  be  delivered,  but  each  pound  will  have  a  correspondingly  lower  heat  value. 
On  the  one  hand  if  the  weather  is  fair  and  the  coal  dries  out  on  the  way,  it  will  weigh 
less  and  the  heating  value  of  each  pound  will  be  correspondingly  higher.  In  other  words, 
under  a  specification,  such  as  is  used  by  the  government,  neither  the  dealer  nor  the 
purchaser  will  gain  or  lose  by  change  in  the  moisture  content  of  the  coal  between  the 
time  it  is  weighed  at  the  mine  and  the  time  it  is  weighed  on  delivery.  The  price  per 
ton  will  be  correspondingly  lower  if  the  coal  is  wet  and  higher  if  it  is  dry. 

In  order  to  determine  the  maximum  variation  in  moisture  in  several  sizes  of 
anthracite  coal,  the  following  experiments  were  made:  The  coal  was  soaked  in  water 
to  allow  it  to  absorb  as  much  moisture  as  possible,  the  result  representing  the  extreme 
conditions  due  to  rains  or  other  causes.  Each  sample  was  then  weighed  and  allowed 
to  dry  in  a  room  exposed  to  the  air.  When  this  sample  ceased  to  lose  moisture  it  was 
assumed  to  be  air  dried,  which  represents  the  condition  of  least  moisture  to  be  expected 
in  a  delivery  of  coal.  The  results  are  summarized  in  the  following  table: 

EXPERIMENTS  TO   DETERMINE   POSSIBLE   VARIATION   OF  MOISTURE   IN  ANTHRA- 
CITE COAL  DURING  SHIPMENT 


Furnace. 

Pea. 

Buckwheat. 

Number  of  samples  used  in  experiment  

13 

10 

12 

Number  of  hours  dried  in  air  at  ordinary  room  tem- 
perature .                

0  .  5  to  24 

24 

24 

Total  moisture  in  thoroughly  wet  coal  4  .... 

5.12 

5.75 

8  44 

Moisture  in  air-dried  samples  

3.58 

1.84 

2  24 

Loss  of  moisture  

.73  to  1.54 

3.1  to3  .9 

4  .  5  to  6  .  2 

Percentage  of  maximum  variation  in  moisture  from 
wet  to  air-dried  coal          .        

30 

68 

74 

The  air-dried  anthracite  still  contains  from  1.8%  to  3.6%  of  moisture.  Moisture 
in  air-dried  coal  varies  with  the  weather,  just  as  it  does  in  wood. 

The  moisture  in  air-dried  bituminous  coal  depends  upon  the  character  of  the  coal. 
It  is  about  1%  in  West  Virginia  coal  and  about  7%  in  Illinois  coal.  The  moisture 
in  the  same  Illinois  coal  delivered  may  range  from  7%  to  17%. 

Owing  to  these  variations  some  method  should  be  used  to  correct  for  the  differ- 
ence in  moisture  in  coals  of  different  character. 

Sampling  Coal. — The  following  suggestions  are  presented  for  the  guidance  of 
those  who  wish  to  send  samples  to  a  laboratory  for  analysis: 

If  samples  are  taken  at  the  building  as  the  coal  is  delivered,  it  will  usually  be 
satisfactory  to  take  one  shovelful  of  coal  from  each  third  of  fifth  wagon  load,  the  loud 


SOLID   FUELS  175 

being  selected  without  the  knowledge  of  the  driver.  It  must  be  kept  in  mind  that 
the  main  object  is  to  obtain  a  portion  of  coal  which  represents  as  nearly  as  possible 
the  entire  delivery.  The  sample  should  contain  about  the  same  proportion  of  lump 
and  fine  coal  as  exists  in  the  shipment  as  a  whole.  The  practice  of  taking  a  shovelful 
near  the  bottom  of  the  pile  should  be  avoided,  as  the  larger  lumps  of  coal  roll  down 
and  collect  near  the  bottom  and  such  a  sample  will  not  truly  represent  the  coal. 

These  samples  should  be  immediately  deposited  in  a  metal  receptacle  having  a 
tight-fitting  cover  and  provided  with  a  first-class  lock. 

Except  when  samples  are  being  deposited  or  when  the  contents  are  being  quar- 
tered down,  this  receptacle  should  be  securely  locked  and  the  key  held  by  a  responsible 
employee.  The  receptacle  should  be  placed  in  a  comparatively  cool  location  to  avoid 
loss  of  moisture  in  the  coal.  When  it  becomes  filled,  or  at  the  end  of  a  sampling  period, 
the  contents  should  be  emptied!  on  a  clean  dry  floor,  in  a  cone-shaped  pile.  The  larger 
lumps  should  be  broken  down  by  a  coal  maul  or  sledge,  and  the  pile  reformed  arid 
quartered  into  four  equal  parts,  a  shovel  or  board  being  used  to  separate  the  four 
sections.  Two  opposite  sections  should  then  be  rejected  and  the  remaining  two  again 
mixed,  broken  dowrn,  and  reformed  into  a  pile  to  be  quartered  as  before.  This  pro- 
cess should  be  continued  until  the  lumps  are  no  larger  than  the  size  of  a  pea,  and  a 
quart  sample  is  finally  procured.  The  samples  should  then  immediately  be  placed  in 
suitable  receptacles  for  shipping  and  sealed  air  tight.  The  Geological  Survey  inspec- 
tors use  a  metal  can,  3  inches  in  diameter  and  9  inches  high,  svith  a  screw  cap  2 'inches 
in  diameter  for  making  the  shipments  to  the  chemical  laboratory.  These  cans  are  sealed 
air-tight  by  winding  adhesive  electrical  tape  around  the  joint  of  the  screw  cap.  Each 
can  holds  a  quart  of  about  2  Ibs.  of  coal. 

The  process  of  quartering  down  and  preparing  samples  for  shipment  to  the  chem- 
ical laboratory  for  analysis  should  be  carried  on  as  rapidly  as  possible  to  avoid  loss 
of  moisture. 

The  samples  should  be  forwarded  promptly  and  notice  of  shipment  sent  under 
separate  cover.  Receptacles  should  be  marked  plainly  on  the  outside,  and  a  corre- 
sponding number  or  description  should  be  placed  inside.  A  complete  record  of  all 
deliveries  should  be  kept,  showing  dates,  names  of  contractor,  kind  of  coal,  total 
weight  delivered,  condition  of  coal  (wet  or  dry),  and  other  particulars  of  import- 
ance. 

The  procedure  at  the  Chemical  Laboratory  of  the  Geological  Surve}*  testing  plant 
is  described  in  Survey  Bulletin  No.  261.  The  samples  are  crushed  and  ground  to  a 
fine  powder,  and  then  analyzed  and  tested.  Persons  not  experienced  in  taking  sam- 
ples have  a  tendency  to  select  a  sample  better  than  the  average.  In  many  cases  a 
lump  of  coal  is  broken  and  shipped  in  a  cloth  sack  to  the  laboratory.  This  allows 
the  moisture  to  dry  out;  moreover,  the  lump  selected  is  usually  free  from  layers  of 
.slate  and  impurities,  and  of  course  then  represents  the  best  coal  in  the  lot,  and  shows 
a  higher  value  than  can  be  expected  to  hold  throughout  the  coal  delivered. 

The  preceding  statements  show  that  the  purchaser  should  usually  have  the  quality 
determined  on  the  basis  of  coal  "as  received"  in  order  to  correct  any  excess  or  defi- 
ciency in  the  moisture  content. 

In  the  purchase  of  coal  for  producer  work,  the  minimum  size  of  mesh  to  be  speci- 
iied  should  not  be  less  than  \  inch.  This  is  to  prevent  excessive  packing,  inasmuch  as 


176 


GAS   PRODUCERS 


there  will,  in  any  event,  be  sufficient  amount  of  powdered  coal  to  fill  all  voids  by 
reason  of  the  fining  of  the  coal  at  an  early  temperature. 

Storage  of  Coal. — The  spontaneous  combustion  of  coal  is  due  primarily  to  the 
pid  absorption  of  oxygen  by  the  finely  divided  coal  and  to  the  oxidation  of  iron 
pyrites  occurring  in  the  coal.  The  conditions  favorable  to  this  process  are:  first,  a 
supply  of  air  sufficient  to  furnish  oxygen,  but  of  insufficient  volume  to  carry  off  the 
heat  generated;  second,  finely  divided  coal,  presenting  a  large  surface  for  the  absorp- 
tion of  oxygen;  third,  a  considerable  percentage  of  volatile  matter  in  the  coal;  and 
fourth,  a  high  external  temperature. 

A  good  way  to  extinguish  a  fire  in  a  coal  pile  not  provided  with  ventilators  con- 
sists in  removing  and  spreading  out  the  coal  and  flooding  the  burning  part  with 
water.  Another  method  consists  in  driving  a  number  of  iron  or  steel  pipes  provided 
with  "driven  well  points"  at  the  place  where  combustion  is  taking  place,  and  through 
these  forcing  water  or  steam  on  the  fire. 

Another  method  being  adopted  by  one  of  the  gas  companies  storing  a  particularly 


-4,0- 


235  B  H.P.- 175  K  W  Plant,  Belted.      Load  -  Constant  full  rating 


Summary  of  tests 

PRODUCER  GAS  POWER  PLANT 

Comparative  Duty -Various  Grades  of  Coal 

Average  of  18  tests  of  fuels 

U.S. Government  Testing  Plant. 

St.  Louis,  Mo. 


FIG.  96. — Pounds  of  various  Coals  per  Horse-power. 


inflammable  coal,  is  to  store  the  coal  in  large  concrete  tanks  which  are  flooded  with 
water,  the  water  being  drawn  when  the  coal  is  desired  for  use. 

The  coal  department  of  the  A.  D.  Little  laboratory,  Boston,  has  found  instances 
where  a  small  coal  pile  cooled  down  after  being  as  hot  as  165°  F.  This  was  probably 
a  rare  occurrence  as  the  temperature  generally  increases  rapidly  as  the  coal  heats  up 
above  150°;  and  there  is  no  doubt  that  when  212°  F.  is  reached  the  coal  must  be 
moved,  or  soon  steps  will  have  to  be  taken  to  cool  it  in  order  to  prevent  fire.  Tem- 
peratures as  high  as  485°  F.  have  been  observed,  and  at  that  temperature  the  coal 
ienited  when  exposed  to  the  air. 


SOLID  FUELS  177 

Transportation. — The  best  engineering  practice  dictates  the  shipping  of  coal 
rather  than  of  coke,  by  reason  of  the  considerable  bulk  of  the  latter  per  unit  of  weight. 
The  standard  coke  car  holds  20  tons  of  coke,  maximum  car  30  tons;  standard  coal  car 
holds  50  tons.  Even  if  it  be  taken  into  consideration  that  1.25  to  1.35  tons  of  average 
coking  coal  is  necessary  for  the  production  of  one  ton  of  coke,  it  would  still  be  prefer- 
able to  ship  the  coal.  Railroad  rates  upon  shipping  coal  are  materially  cheaper  than 
for  shipping  coke,  for  the  above  reasons. 

Coal  and  Lignite  Compared. — The  following  is  a  summary  of  results  from  fuels 
tested  by  the  gas  producer  division  U.  S.  Geological  Survey  fuel  testing  plant,  at  St. 
Louis,  Mo.,  during  the  year  1905. 

B.T.U.  per  Pound. 

Coal  as  fired 12,500 

Lignite 7,526 

Dry  coal 13,420 

Dry  lignite 10,870 

Average  B.T.U.  per  cubic  foot  of  gas  from  coal 151 . 

Average  B.T.U.  per  cubic  foot  of  gas  from  lignite 161 . 

Average  cubic  feet  of  gas  per  pound  of  coal  as  fired 59 .8 

Average  cubic  feet  of  gas  per  pound  of  lignite  as  fired 29 . 1 

Average  cubic  feet  of  gas  per  pound  of  dry  coal 64 .4 

Average  cubic  feet  of  gas  per  pound  of  dry  lignite 40 . 9 

Average  pounds  of  coal  as  fired  per  square  foot  of  fuel  bed  area 8.0 

Average  pounds  of  lignite  as  fired  per  square  foot  of  fuel  bed  area 14. 5 

Average  pounds  of  dry  coal  per  square  foot  of  fuel  bed  area 7.4 

Average  pounds  of  dry  lignite  per  square  foot  of  fuel  bed  area 10 . 1 

Average*  equivalent  pounds  coal  as  fired  per  e.h.p.  developed 1 .74 

Average  equivalent  pounds  lignite  as  fired  per  e.h.p.  developed 2.94 

Average*  equivalent  pounds  dry  coal  per  e.h.p.  developed 1 .56 

Average  equivalent  pounds  dry  lignite  per  e.h.p.  developed 2.04 

Ratio  of  total  coal  per  e.h.p.  (under  boiler)  to  total  coal  per  e.h.p.  (in  pro- 
ducer) equals 2.7 

Ratio  of  total  lignite  per  e.h.p.  (under  boiler)  to  lignite  per  e.h.p.  (in  pro- 
ducer) equals 2.6 

Pounds  of  mixture  of  tar,  water,  soot,  etc.,  delivered  by  tar  extractor  per 

ton  of  coal 385 . 

Pounds  of  mixture  of  tar,  water,  soot,  etc.,  delivered  by  tar  extractor  per 

ton  of  lignite 175 . 

Average  sulphur  in  coals  tested,  per  cent 2 . 55 

Average  sulphur  in  lignites  tested,  per  cent 2 .00 

AVERAGE  OF  GAS  ANALYSES 

Coal.  Lignite. 

Carbon  dioxide,  CO, 9.5  9.1 

Oxygen,  O2 0.0  0.0 

Ethylenef,  C2H< 0:0  0.0 

Carbon  monoxide,  CO 19  .2  22 .6 

Hydrogen,  H2 12.4  14.6 

Methane,  CH4 3.1  3.0 

Nitrogen,  N2 55 .8  50 .7 

*  This  includes  all  coal  charged  to  producer  and  coal  for  auxiliary  boiler, 
t  Not  separated  from  Methane  (CH4>  in  this  series  of  tests. 

Producer  Fuel  Tests. — At  the  U.  S.  Geological  Survey  fuel  testing  plant  at  St. 
Louis,  Mo.,  a  long  series  of  tests  were  made  of  fuels  used  in  gas  producers  and  the 
results  are  now  published. 


178 


GAS   PRODUCERS 


The  equipment  used  was  a  250  h.p.  pressure  producer  with  a  centrifugal  tar 
extractor  and  gas  holder.  A  235  h.p.  3-cylinder  vertical  gas  engine  belted  to  a  gen- 
erator produced  power  which  was  measured  by  electric  instruments  connected  with 
the  switchboard.  As  will  be  seen  the  results  obtained  are  much  better  than  those 
from  steam  plants  of  corresponding  size.  The  following  table,  in  which  the  word 
equivalent  means  total  fuel  used  in  producer  and  steam  boiler,  gives  in  abstract  the 
results  obtained. 


Fuel. 

Florida  Peat. 

Four 
Lignites, 
Average. 

Four 
Illinois 
Coals, 
Average. 

Four 
Pennsylvania 
Coals. 
Average. 

Four 
West  Virginia 
Coals. 
Average 

PROXIMATE  ANALYSIS: 
Moisture  

21.00 

35.05 

11.51 

3.47 

2   47 

Volatile  matter.  

51.72 

28.96 

31.81 

19.68 

32.12 

Fixed  carbon.  .  .  ;  

22.11 

27.72 

43.46 

67.31 

GO  24 

Ash   .        .        .    .    

5.17 

8.27 

13.22 

9.54 

5.17 

B.T.U.  per  fuel  pound: 
As  fired  

8,127 

7,164 

10,651 

13,651 

14,248 

Dry 

10,299 

11,038 

12,030 

14,lc6 

14,610 

Gas  made  cu.ft.  per  Ib.  equivalent  fuel: 
As  fired  

28.5 

26.3 

49.6 

71.4 

77  5 

Dry                      

36.1 

40.3 

56.1 

74.0 

79  5 

B.T.U.  gas,  per  cu.ft  

175.2 

169.9 

153.2 

141.6 

149.6 

Fuel,  equivalent  per  b.h.p.  hour: 
As  fired 

2  57 

2  43 

1  66 

1  16 

1  03 

Dry. 

2.03 

1.73 

1.47 

1.12 

1.00 

Of  the  four  Pennsylvania  coals  tested,  two  came  from  the  lower  Kittanning  bed, 
one  from  the  lower  Freeport,  and  the  fourth  from  the  Pittsburg  bed.  Of  the  West 
Virginia  coals,  one  came  from  the  Ansted  bed,  another  from  the  Eagle,  both  of  these 
being  mined  in  the  New  River  district;  a  third  from  the  Pittsburg,  and  the  fourth 
from  the  Keystone  bed. 

Clinkering  Test. — The  most  satisfactory  preliminary  test  of  a  coal  is  by  a  dimin- 
utive gas  apparatus  capable  of  treating  a  few  pounds  of  coal  and  so  disposed  as  to 
permit  measurement  of  the  gas  and  by-products.  Chemical  examination  alone  affords 
insufficient  data.  While  a  "proximate  analysis"  showing  specific  gravity,  moisture, 
volatile  matter,  fixed  carbon,  ash,  and  sulphur  affords  some  criterion  of  its  value,  about 
the  only  advantage  of  an  ultimate  or  elementary  analysis  is  the  knowledge  of  the  per- 
centage of  free  hydrogen  present;  poor  gas  coals  have  less  than  4%,  and  those  very 
rich  over  5%. 

Some  varieties  yield  their  gas  more  readily  than  others,  but  it  serves  economy  to 
use  it  as  soon  as  possible  after  mining.  Long  storing  or  weathering  diminishes  yield 
of  gas  and  impairs  its  quality.  Much  moisture  lowers  the  heat  of  retorts,  promotes 
the  formation  of  condensable  constituents,  produces  less  gas  of  poorer  quality,  and 
liberates  a  portion  of  the  sulphur  which  otherwise  would  be  retained  by  the  coke. 
Protection  during  necessary  storage  is  therefore  very  desirable  and  should  be  secured 
with  efficient  ventilation  to  guard  against  spontaneous  ignition. 

The  yield  of  Pennsylvania  gas  coals  in  present  practice  is  something  over  10,500 


SOLID   FUELS 


179 


cubic  feet  of  18  candle-power  gas  per  gross  ton,  depending  very  much,  however,  upon 
the  general  conditions  surrounding  the  plant. 

A  fair  idea  of  the  fuel  for  producer  work  may  be  obtained  by  using  a  short  piece 
of  pipe,  6  or  8  ins.  diameter  and  2  or  3  feet  long,  in  connection  with  an  ordinary  black- 
smith's forge.  The  pipe  should  set  on  end  over  the  air  inlet  of  the  forge  and  the  fire 

started  within   it,    after   which   fuel   is   gradually  fed 
in  in  varying  quantities  and  to  various  depths. 

The  pressure  and  amount  of  the  air  blast  can 
be  altered  and  the  fuel  consumed  at  different  rates 
of  combustion. 

The  gas  escaping  from  the  top  of  the  pipe  may 
be  lighted,  and  from  the  nature  of  this  flame  the  rate 
of  combustion  and  the  nature  of  the  resultant  clinker' 
and  ash,  the  quality  of  the  fuel  may  be  approximately 
determined. 

Gas  Yields  of  Coals. — In  presenting  the  ac- 
companying charts,  too  much  emphasis  cannot 


fe   10 
ti     8 


-•  9,000          10,000         11,000        12,000        13,000        14,000         15,000 
B.T.U  PER  LB.  OF  COAL  AS  FIRED 

FIG.  97. — Combustion  Test  for  Coal.     FIG.  98. — Relation  of  Richness  of  Coal  to  Rate  of  Combustion. 

be  given  to  the  fact  that  the  tests  from  which  these  curves  were  deduced  have 
been  subjected  to  absolutely  no  refinements.  With  the  possible  exception  of  two  or 
three  coals,  one  test  only  has  been  made  on  each  fuel,  and  the  result  of  each  test  has, 
to  a  great  extent,  depended  upon  the  ability  of  the  producer  operator  to  "catch  on" 
to  the  methods  of  handling  a  given  coal  within  the  eight  or  ten  hours  allowed  pre- 
liminary to  the  official  test. 

It  should  also  be  borne  in  mind  that  all  the  tests  have  been  made  on  one  type  and  in 
one  size  of  producer — a  type  designed  primarily  for  anthracite  coal — and  that  it  has  been 
imperative  that  the  test  be  made  and  the  required  power  generated  without  regard  to  the 
proper  relations  between  the  gas-producing  qualities  of  the  coal  and  the  fuel-bed  area. 

The  restrictions  have  been  such  that  the  tests  have  been  conducted  on  the  basis 
of  steady  load  on  the  engine  (325  brake  horsepower)  and  not  on  the  basis  of  maxi- 
mum power-producing  quality  of  the  coal. 


180 


GAS   PRODUCERS 


M 

,         ,00 

< 

*j      70- 


"^1        4o 


fooo  /oooo  IIO»o  nooo  13000  /+'ooo  /sooo 

B.  T.  U .  Per  t&  of  Co  At    ct,s  fiirrat 

FIG.  99.— Relation  of  B.T.U.  of  Coal  to  cu.ft.  per  Ib. 


I 


60 


fooo 


IOOOO  II  OOO 


liooo 


ooo  IS  ooo 


M.  T  U.  Per  l&   of  Coa.L      *t    Ft 

FIG.  100.— Relation  of  B.T.U.  per  Pound  to  Producer  Efficiency. 


SOLID  FUELS 


181 


In  spite  of  those  restricted  conditions,  the  general  conclusions  derived  from  tests 
upon  fifty  odd  coals  made  during  1905  are  regarded  as  sufficiently  significant  for  pre- 


2-5 
2-0 

1-5 

I  0\ 


ooo  10090  i/ooo  tzooo  1300 


B.T.U.  per  I  £i  of  Coxl    as  Fir  fat 

FIG.  101.  —  Richness  of  Coal  and  Power  Yield. 


070 


5       6        7        8        9       10      11       12      13      U      16 

tB8.  OF  COAL  PER  SQ.  FT.  OF  FUEL-BED  AREA  PER  HOUR 


FIG.  102. — Relation  of  Combustion  Rate  to  Gas  Yield  per  Pound. 

sentation  at  this  time,  although  subject  to  modification  in  the  light  of  later  investi 
gations.     They  are  accordingly  indicated  in  the  following  diagrams: 

According  to  another  authority  the  quantity  of  gas  produced  from  a  ton  of  coal 
varies  with  the  composition  and  general  character  of  the  coal  and  the  method  of  oper- 


182 


GAS   PRODUCERS 


ation,  of  which  we  may  note  especially  the  proportion  of  steam  used  in  blowing  the 
producer.  But  on  the  average  it  may  be  assumed  that  one  ton  of  anthracite  buck- 
wheat coal  produces  about  170,000  cu.ft.  of  gas,  containing  138  heat  units  per 
1000  cu.ft.  Its  composition  will  average  as  follows: 


Producer  Gas. 


Per  Cent. 


CO,  carbon  monoxide 22 . 0  to  30 . 0 

H,  hydrogen 15.0"     7.0 

CH4,  methane,  marsh  gas 3.0"     1.5 

CO2,  carbon  dioxide,  "carbonic  acid" 6.0"     1.5 

N,  nitrogen 54.0  "  60.0 

The  analysis  of  gas  from  bituminous  coal  is  nearly  the  same,  except  that  CH4 
is  a  trifle  higher  and  the  H  frequently  above  the  maximum  noted  in  table.     But,  as 

a  matter  of  fact,  an  analysis  of 
bituminous  gas  does  not  properly 
represent  its  energy,  as  some  of 
the  volatile  combustible  of  the 
coal  passes  off  as  a  non-fixed 
Vapor  and  does  not  appear  in 
the  analysis  (being  condensed 
in  the  tubes  of  the  analytical 
apparatus),  yet  it  is  utilized  in 
the  furnace. 

The  yield  of  gas  from  differ- 
ent fuels  varies  within  wide  limits, 
depending  upon  the  composition 
and  general  character  of  the  fuel 


0  100 

1  80 

I 

»    60 

o 

O     40 


66        7        8        9       10      11       12      13      14       15 
LBS.  OF  COAL  PER  SO.  FT.  OF__FUEL-BEO  AREA  PER  HOUl 


FIG.  103.- 


-Relation  of  Combustion  Velocity  to  Efficiency 
of  Producer. 


and  method  of  operation.     More 
as  an  index  to  differences  of  yield 

than  as  accepted  data  the  following  figures  are  given  for  the  fuel  free  from  ash,  the 

dry  gas  and  an  air  blast: 


Producer  Fuel. 


Yield  per  Pound, 
Cubic  Feet. 


Producer  Fuel. 


Yield  per  Pound, 
Cubic  Feet. 


Coke  or  charcoal 104 

Bituminous  coal 75 

Brown  coal.  .  55 


Turf 45 

Wood.  .  35 


ANALYSIS  OF  PENNSYLVANIA  GAS  COAL  AND  GAS  GENERATED  FROM  SAME  BY  A 

SMITH  PRODUCER 

Analysis  of  Coal.                                            Per  Cent.  Analysis  of  Coal.                                       Per  Cent. 

Moisture 1.19  Ash 6.26 

Volatile  carbon 36 . 05  Sulphur 0 . 74 

Fixed  carbon 55 . 76 

Analysis  of  Gas.                                           Per  Cent.  Analysis  of  Gas.                                   Per  Cent. 

Hydrogen,  H 11 .41  Carbon  monoxide,  CO 22.98 

Oxygen,  0 0 . 08  Carbon  dioxide,  C02 4 .04 

Carbohydrates 3.61  Nitrogen,  N 57.88 


SOLID   FUELS 


183 


ANALYSIS  OF  ANTHRACITE  GAS,  SMITH  SUCTION  PRODUCER 
Load  less  than  25%  of  rated  capacity 


COz. 
'8 

4 

5 


CO2. 

5.0 

4.0 
9.0 
7.0 
4.8 


o. 

0.7 
0.2 
2.0 


CO. 

20.3 
27.0 
23.5 


H. 

17.0 
13.9 
12.0 


N. 

54.0 
54.9 
57.5 


Load  25  to  125%  of  rated  capacity 


O. 

1.0 
1.0 
1.0 
2.0 
0.2 


CO. 

22.0 
23.0 
21.0 
23.0 
25.6 


H. 

21.3 
22.6 
21.5 
23.5 
22.9 


N. 

50.7 
49.4 
47.5 
44.5 
46.5 


Heating  Capacity. 

131 
140 
121 


Heating  Capacity. 

157 
158 
146 
160 
167 


LIGNITE  GAS 
COj.  O.  CO.  H.  N.  Heating  Value. 

8.4  1.8  18.3  25.6  45.9  152 

8.0  3.5  15.5  27.0  46.0  147 

6.6  2.2  20.2  25.0  46.0  165 

The  analyses  given  are  selected  at  random,  and  from  producers  of  from  25  to 
200  h.p.  rated  capacity,  and  under  all  possible  conditions  of  load  and  service. 


ANALYSIS  OF  SEMI-ANTHRACITE  BEING  RUN  IN  FAIRBANKS-MORSE  SUCTION 

PRODUCERS 

Per  Cent. 

Fixed  carbon 75 . 30 

Volatile  combustibles 7.40 

Ash 15.10 

Moisture 2 . 20 

Sulphur • 2.99 

Heat  value  per  pound,  B.T.U 12,020 

This  coal  comes  from  the  neighborhood  of  Bernice,  Pa. 

Lignites. — The  Power  and  Mining  Machinery  Co.  have  tried  lignite  in  their 
Loomis-Pettibone  gas  producers  installed  at  their  works  and  the  results  have  been 
highly  satisfactory.  The  lignites  used  were  mined  in  North  Dakota  and  gave  fol- 
lowing analyses: 


U.  S.  GEOLOGICAL  SURVEY 

Moisture 39 . 56 

Volatile  matter 27 . 78 

Fixed  carbon 26 . 30 

Ash 6 . 36 

Sulphur 0.93 


WASHBURN  LIGNITE  COAL  CO. 

Moisture 22.06 

Volatile  matter 42 . 72 

Fixed  carbon 30.50 

Ash..  4.72 


184  GAS   PRODUCERS 

The  following  figures  are  the  results  obtained  in  a  test  made  with  this  coal: 

Hours  run 93 

Total  lignite  consumed  in  generators,  Ibs 1862 

Total  coke  consumed  in  generators,  Ibs 795 

Total  b.h.p.  hours  (corrected) 8289 

Lignite  per  b.h.p.  hour,  Ibs 2 . 24 

Coke  per  b.h.p.  hour,  Ibs 0.09 

Lignite  consumed  per  hour  in  generator,  Ibs 200 

Lignite  consumed  per  square  foot  of  grate  surface  in 

generator,  Ibs 20 

The  approximate  yield  of  gas  was  arrived  at  by  the  occasional  observation  of 
the  holder.  The  cubic  feet  of  gas  per  pound  of  fuel  averaged  44. 

The  gas  furnished  in  every  respect  proved  itself  extremely  desirable  for  use  in 
the  gas  engines  then  being  run  at  the  shop.  The  gas  producer  ran  from  2  to  3  hours 
without  reversing,  consequently,  the  percentage  of  variation  of  hydrogen  is  extremely 
low.  The  gas  averaged  105  to  110  B.T.U.'s  per  cubic  foot. 

Experiments  made  in  the  application  of  Texas  lignite  in  revolving  bottom  gas 
producers,  under  the  inspection  of  the  State  geologist  of  Texas,  resulted  in  demon- 
strating its  great  worth  as  a  basis  of  gas  production.  The  lignite  tested  resembles 
in  composition  much  of  this  class  of  fuel  abounding  in  the  Western  states. 

TEXAS  LIGNITE  COMPOSITION 

Per  Cent. 

Moisture 21 .86 

Volatile  matter 31.81 

Fixed  carbon 36 .85 

Ash 9.48 

The  gas  is  high  in  hydrocarbons,  and,  as  a  consequence,  its  flame  produces  an 
intense  heat. 

The  following  analysis  of  the  coal  and  gas  show  the  result  of  gasifying  similar 
Peruvian  coals: 

PERUVIAN  COAL  PRODUCER  GAS 

Water 18                    C02 6.4 

Volatile  matter 40                    C2H4 0.7 

Fixed  carbon 31                     0 0.8 

Ash 9                     CO .  22.0 

Sulphur 3.5                 H 9.6 

CH4 1.6 

N 58.9  (diff.) 

Gas  from  the  earthy  and  brown  coals  is  very  largely  employed  in  Europe  in 
many  metallurgical  works  and  manufactories  requiring  high-temperature  furnaces, 
as  in  iron  and  steel,  potteries,  glass  works,  etc.  There  is  no  apparent  reason  why 
the  lignitic  coals  of  the  West  should  not  be  as  satisfactorily  used. 


SOLID    FUELS  185 

ANALYSIS  OF  NEW  MEXICO  LIGNITE 

AMERICAN  FUEL  Co. 
Car  sample  as  received: 

Per  Cent.  Per  Cent. 

Moisture 12.29         Ash 6.99 

Volatile  matter 34.58        Calorific  value,  B.T.U 11,252 

Fixed  carbon 46. 14 

Analysis  of  air-dried  sample: 

Moisture 10.86        Ash 7. 10 

Volatile  matter 35. 14        Calorific  value,  B.T.U 11,290 

Fixed  carbon 46 . 90 

CALEDONIA  COAL  COMPANY,  OTERO  MINE,  NEAR  GALLUP 

Analysis  of  sample  as  received: 

Per  Cent.  Per  Cent. 

Moisture 10.79        Ash 18.66 

Volatile  matter 33.82        Calorific  value,  B.T.U 9,907 

Fixed  carbon 36. 73 

Analysis  of  air-dried  sample: 

Moisture 8.13        Ash 19.22 

Volatile  matter 34.82        Calorific  value,  B.T.U 10,136 

Fixed  carbon 37.83 

ANALYSIS  OF  WASHINGTON   LIGNITES 

Per  Cent.  Per  Cent. 

Ash 4.01         Sulphur 0.10 

Volatile  matter 38.42        Moisture 18.07 

Carbon 39.40 

GAS  FROM  LIGNITES 

Constituents.  Simpson  Mine,  Colorado.     Hoyt  Lignite,  Texaa. 

Lignite:  Moisture 20.24  33. 71 

Volatile  matter 32.26  29.25 

Fixed  carbon 41.65  29.76 

Ash 5.85  7.28 

Sulphur .60  .53 

Gas:  C02 10.11  9.60 

O .55  .20 

CO 17.38  18.22 

H 11.05  9.63 

CH4 5.00  4.81 

N 55.90  57.53 

B.T.U.  per  Ib.  as  fired 9767  7348 

Gas  per  Ib 42.1  cu.ft.  34.2  cu.ft. 

B.T.U.  per  cu.ft 149.  156.2 


186  GAS    PRODUCERS 

Gas-house  Coke. — Where  gas-house  coke  is  used  as  a  producer  fuel,  great  care 
should  be  taken  that  the  coke  thoroughly  carbonized  and  a  uniform  quality  through- 
out, for  should  the  coke  be  green,  it  would  be  found,  especially  in  up-draft  producers, 
that  the  volatile  matter  and  heavier  hydrocarbons,  which  have  not  been  evaporated 
during  the  dissociation  process,  will  be  distilled  and  carried  off  together  with  fine 
dust  in  the  form  of  paste,  which  is  exceedingly  difficult  of  separation  from  the  gas. 

This  " tar-fog"  or  mist,  entrains  mechanically  dust  and  dirt  from  both  the  fuel 
itself  and  the  blast  and,  going  over  in  the  form  of  paste  which  is  almost  inseparable 
from  the  gas,  creates  a  stoppage  wherever  bends  or  turns  occur  in  the  pipe,  and  also 
in  the  mixing  chamber  and  governor  valve  of  the  engine,  besides  creating  a  "muck" 
inside  of  the  cylinders. 

The  coke  used  as  producer  fuel  should  be  crushed  to  not  exceed  a  1.5-inch  mesh 
in  order  to  prevent  an  inefficient  percentage  of  voids.  The  bed  should  be  carried  some 
50%  deeper  than  in  the  case  of  anthracite,  in  order  that  additional  weight  be  given 
to  the  fuel  bed  and  that  it  may  pack  more  closely,  otherwise  the  coke  on  account  of 
its  lack  of  weight  and  density  is  apt  to  blow  more  readily  into  fissures  and  chimneys,, 
permitting  the  undissociated  passage  of  the  air. 

A  compactness  of  fire  bed  is  particularly  necessary  in  the  operation  of  coke,  as 
its  high  flame  temperature  subtends  the  formation  of  a  particularly  refractory  class 
of  clinker  when  the  blast  is  concentrated  upon  any  section  of  the  bed  through  follow- 
a  line  of  least  resistance,  in  cases  of  honeycombing,  chimneys,  or  blow  holes. 

The  rapidity  with  which  coke  burns,  due  to  its  lack  of  density,  creates  another 
reason  for  close  supervision  of  the  fire  bed,  as  the  nature  of  this  bed,  by  reason  of  the 
rapid  combustion,  alters  continually  and  with  astonishing  rapidity. 

The  efficiency  usually  obtained  with  gas-house  coke  is  about  1.25  Ibs.  of  coal 
per  b.h.p.  hour  on  small  installations. 

PRODUCER  GAS  FROM  COKE,  LOOMIS-PETTIBONE  PRODUCERS 

Galitzen,  24  Hours.         Chest  Creek.        Frick,  1J  Minute  Run.       Chest  Creek,  48  Hours. 

CO2,  H2S 3.9  5.2  4.80  3.50 

0 0.6  0.1  0.80  .50 

CO 44.66  40.9  39.01  40.47 

H 47.81  48.33  50.67  50.70 

N 3.03  5.47  4.72  4.83 

The  above  table  is  a  summary  of  a  number  of  analyses  in  each  case  on  the  differ- 
ent fuels  mentioned,  and  running  under  commercial  conditions  upon  Loomis-Petti- 
bone  apparatus  in  1891.  The  samples  were  taken  during  3-minute  runs,  unless 
otherwise  specified.  The  generators  were  9X14  ft.,  producing  30,000  cu.ft.  per  hour 
per  pair  of  generators. 

Tan  Bark. — Gasification  of  spent  tan  bark  has  also  been  successfully  accom- 
plished. 

The  spent  tan  bark  contained:  moisture,  38.67%;  and  ash  3.24%.  The  gas 
obtained  from  the  producer  plant  of  special  character,  after  its  cooling  and  washing, 
analyzed  as  follows: 


SOLID   FUELS  187 

Per  Cent  by  Volume.  I.  II  III. 

C02 10.8  18.8  15.0 

0 0.6  0.4  0.4 

CO 17.6  10.2  14.2 

CH4 2.4  4.8  5.6 

H 16.4  14.0  8.7 

N 52.2  51.8  56.0 

Calorific  powers  determined  repeatedly  by  a  Junker's  calorimeter  gave  125,  132, 
and  141  B.T.U.  per  cubic  foot.  Mixed  with  25%  of  coke  fines  an  average  of  145 
B.T.U.  was  obtained. 

By-Product  Coke  Oven  Results. — The  following  figures  are  taken  from  the  actual 
records  of  operation  of  an  existing  United-Otto  plant  for  a  period  of  six  months,  and 
are  representative  of  the  returns  that  may  be  expected  under  the  prevailing  conditions. 
A  coal  mixture  averaging  30  to  32%  of  volatile  matter,  gave  the  following  results: 

Average  daily  coal  carbonization 503  net  tons 

Average  yield  of  coke  (per  cent  of  coal) 74% 

Average  yield  of  ammonia  (NH3)  per  net  ton  coal 5.20  Ibs. 

Average  yield  tar  per  net  ton  of  coal 10. 17  gals. 

Average  quantity  illuminating  gas  sold  per  net  ton  coal  corrected  to 

60°  F.  and  29.92  ins.  barometrical  pressure 4,630  cu.ft. 

Average  illuminating  value  of  gas 18.07  candles 

Gas  Analyses.  Illuminating  Gas.    (Fof  Qv^Heating.) 

Illuminants 5.8  2.8 

Methane 40.8  29.6 

Hydrogen 37.6  41.6 

Carbon  monoxide 5.6  6.3 

Carbon  dioxide 3.7  3.2 

Oxygen .4  .4 

Nitrogen 6.1  16.1 

British  thermal  units  (gross)  per  cu.ft 730.3  551.3 

YIELD  OF  COKE  AND  BY-PRODUCTS 

(From  Dry  Coal) 

Per  cent  by  weight. 

Coke 70      to  82 

Heating  gas 12       "11 

Surplus 7.5"     2 

Tar 5       "     2 

Crude  ammonia  liquor 5.5  "     3 

The  results  from  coking  100  net  tons  of  coal  are  as  follows: 

Bee-hive  Ovens:   65  net  tons  coke. 

By-product  Ovens:  75  net  tons  coke,  1,000  gallons  tar,  2,300  Ibs.  sulphate  of 
ammonia  and  450,000  cu.ft.  illuminating  gas. 

Fuel  Data.— The  following  data  may  be  of  service  to  the  user  or  student  of  fuels: 


188  GAS  PRODUCERS 

WEIGHT  PER  CUBIC  FOOT  OF  COAL  AND  COKE 

Pounds  per      Storage  for  Long  Ton, 
Cubic  Foot,  Cubic  Feet. 

Anthracite  coal,  market  sizes,  loose 52-56  40-43 

Anthracite  coal,  market  sizes,  moderately  shaken .  56-60 

Anthracite  coal,  market  size,  heaped  bushel,  loose.  77-83 

Bituminous  coal,  broken,  loose 47-52  43-48 

Bituminous  coal,  moderately  shaken 50-56 

Bituminous  coal,  heaped  bushel 70-78 

Dry  coke 23-32  80-97 

Dry  coke,  heaped  bushel  (average  38) 35-42 

HEATING   VALUE  OF  SOME  FUELS 

B.T.U. 

Peat,  Irish,  perfectly  dried,  ash  4% 10,200 

Peat,  air-dried,  25%  moisture,  ash  4% 7,400 

Wood,  perfectly  dry,  ash  2% 7,800 

Wood,  25%  moisture 5,800 

Tanbark,  perfectly  dry,  15%  ash 6,100 

Tanbark,  30%  moisture 4,300 

Straw,  10%  moisture,  ash  4% 5,450 

Straw,  dry,  ash  4% 6,300 

Lignites 1 1,200 

The  above  are  approximate  figures,  for  on  such  materials  qualities  are  very  vari- 
able. 

Coal  and  coke  are  often  measured  by  the  bushel.  The  standard  bushel  of  the 
American  Gas  Light  Association  is  18^  ins.  diameter  and  8  ins.  deep  =  2150. 42  cu.ins. 
A  heaped  bushel  is  the  same  plus  a  cone  19^  ins.  diameter  and  6  ins.  high,  or  a  total 
of  2747.7  cu.ins.  An  ordinary  heaped  bushel  =  1J  struck  bushel  =  2688  cu.ins.  =  10 
gallons  dry  measure. 

Crude  petroleum  =  7.3  Ibs.  per  gallon. 

ANTHRACITE-COAL  SIZES 

Size  and  Name.  Through  a  Round  Hole.       Over  a  Round  Hole. 

Chestnut H  ins.  diam.  f  ins.  diam. 

Pea.  .  I   "  "  TS    "  " 

No.  1  buckwheat &"  "  t"        " 

No.  2  buckwheat  or  rice f    "  "  &    "  " 

No.  3  buckwheat  or  barley &  "  "  £   " 

Dust &"  " 

Broken 2|    "  " 

Egg 2f  "  "  2     "  " 

Stove 2    "  "  If    "  " 

Chestnut If"  "  f    "  " 

Pea f"  "  |    "  " 

No.  1  Buckwheat £"  "  i"  " 

Rice fr   "  " 


SOLID   FUELS 


189 


WOOD  FUEL 


Weight  per  Cord,      Coaj[  Equivalent, 
Pounds. 


Hickory  or  hard  maple 4500 

White  oak 3850 

Beech,  red  oak,  black  oak 3250 

Poplar,  chestnut,  elm 2350 

Pine 2000 

Sharpless  assumes  a  coal  equivalent  of  about  10%  less  than  that  given  above. 
Coal  and  other  solid  fuels  vary  considerably  in  composition,  as  shown  by  these 

average  examples: 

ANALYSES   OF  FUELS 


Pounds. 

2000 
1711 
1445 
1044 
890 


Water. 

Volatile  Matter. 

Fixed  Carbon. 

Ash. 

Sulphur. 

Anthracite  (mixed)  

3.40 

3   80 

83   80 

8  40 

0  60 

Semi-bituminous  

1  00 

20  00 

73  00 

5  00 

1  00 

Bituminous 

1  20 

32  50 

60  00 

5  30 

1  00 

Lignite  

22.00 

32  00 

37  00 

9  00 

Coke  

89.00 

10.00 

0.80 

Carbon. 

Hydrogen. 

Oxygen. 

Nitrogen. 

Ash. 

Wood,  dry  

50  0 

6  0 

41   0 

1   0« 

2  0 

Charcoal  

75.5 

2  5 

12  0 

1  0 

Peat,  dry  and  ash-free  

58.0 

5.7 

35.0 

1.2 

COMPARATIVE  COST   OF   FUEL    GASES 


Bituminous  producer  gas: 

1  25 

1  50 

1  75 

2  00 

2  25 

2  50 

2  75 

3  00 

3  25 

Cost  per  1000  ft.  gas  

007 

0084 

0097 

01 

012 

013 

015 

016 

018 

Cubic  feet  for  one  cent  ,  

1400 

1200 

1040 

900 

800 

720 

660 

625 

550 

B.T.U.  for  one  cent  

168000 

144000 

124800 

108000 

96000 

86400 

79200 

75000 

66000 

Anthracite  producer  gas: 
Cost  per  ton  coal  

2  75 

3  00 

3  25 

3  75 

4  00 

Cost  per  1000  ft  gas  

015 

016 

018 

019 

022 

Cubic  feet  for  one  cent  

660 

625 

550 

500 

460 

B.T  U.  for  one  cent  

79200 

75000 

66000 

60000 

55200 

Fuel  oil: 

2i 

2i 

2f 

3 

31 

3i 

3f 

4 

4i 

4* 

4| 

B.T  U.  for  one  cent  

60450 

54400 

49400 

45600 

41800 

38800 

36200 

34000 

31000 

30000 

38600 

Coal  gas  or  water  gas: 
Cost  per  1000  ft.  gas  

80 

90 

1  00 

1  10 

1  15 

1  20 

1  25 

Cubic  feet  for  one  cent  

12  5 

11  1 

10 

9 

8  7 

8  3 

g 

B.T.U.  for  one  cent  

6570 

5838 

5260 

4734 

4576 

4365 

4203 

Natural  gas: 
Cost  per  1000  ft.  gas,  cents.  .  .  . 

.10 

.15 

.20 

.25 

30 

Cubic  feet  for  one  cent  

100 

66 

50 

40 

33 

B.T.U.  for  one  cent  

96700 

63800 

48300 

38700 

31900 

Coke-oven  gas: 
Cost  per  1000  ft.  gas,  cents  
Cubic  feet  for  one  cent  

4 
250 

4 

220 

5 

200 

64 

180 

6 
166 

6i 
153 

7 
143 

7* 
133 

8 
125 

9 
111 

10 
100 

B.T.U.  for  one  cent  .  . 

136200 

119100 

109000 

98100 

90500 

83400 

77POO 

72400 

68100 

60500 

M.'snrr 

ANALYSES  OF  ABOVE  GASES 


B.T.U. 
per 

Cu.ft. 

Hydro- 
gen. 

Me- 
thane, 
CH4. 

Carbon 
Mon- 
oxide, 
CO. 

Ethyl- 
ene, 
Crfls. 

Carbon 
Di- 
oxide, 
CO-. 

Nitro- 
gen, 

N. 

Oxygen, 
gen, 
O. 

PerCent 
Total 
Com- 
bustible 

PerCent 
Total 
Incom- 
bustible 

Bituminous  producer  gas      

131  2 

13 

5 

15 

0  2 

7  3 

59 

0  5 

33  2 

66  8 

Anthracite  producer  gas 

127  5 

15 

2  5 

20 

0  0 

8  0 

54 

0  5 

37  5 

62  5 

Fuel  oil,  per  pound  

20000 

Coal  gas  or  water  gas  

52R  5 

40 

25 

19 

8  5 

3  0 

4  0 

0  5 

92  5 

7  5 

Natural  gas           

967   2 

3 

92 

0 

3 

0 

2 

0 

98 

2 

Coke-oven  gas  

545  .  2 

50 

6 

6 

4 

1.5 

2 

0.5 

96 

4 

CHAPTER  VII 
PHYSICAL  PROPERTIES  OF  GASES 

SIEBEL  defines  a  gaseous  body  as  follows:  "Speaking  more  specifically,  a  gas  is 
a  body  in  which  the  distance  between  the  constituent  atoms  or  molecules  is  so  great 
that  the  dimensions  of  the  molecules  themselves  may  be  neglected  in  comparison 
therewith.  The  atoms  or  molecules  in  a  gas  are  constantly  vibrating  to  and  fro,  and 
the  average  momentum  or  energy  of  this  motion  represents  the  temperature  of  the 
gas.  The  vehemence  or  force  with  which  the  atoms  or  molecules  impinge  on  the 
walls  of  a  surrounding  vessel  in  consequence  of  this  motion  represents  the  pressure 
of  the  gas." 

Regardless  of  quantity  of  a  gas,  it  will  always  fully  occupy  the  vessel  or  space 
which  contains  it.  The  force  which  this  gas  exerts  when  confined  in  a  limited  space 
is  known  as  "tension." 

General  Properties  of  Gases. —  Unit  of  Pressure. — The  general  unit  of  pressure  is 
the  pressure  of  the  atmosphere  per  square  inch,  which  is  equal  to  that  of  a  column 
of  water  of  about  30  feet,  or  that  of  a  column  of  mercury  of  about  30  inches,  and  also 
equivalent  to  a  pressure  of  14.7  pounds — in  round  numbers  15  pounds  per  square 
inch. 

Manometer  Gauges. — Glass  tubes  filled  with  mercury  are  frequently  used  to  meas- 
ure higher  pressures  than  that  of  the  atmosphere  and  are  called  manometers.  For 
this  purpose,  however,  aneroid  gauges  are  used  chiefly  for  the  measurement  of 
atmospheric  boiler  and  vacuum  pressures. 

Action  of  Vacuum. — The  pressure  of  the  atmosphere  is  the  cause  of  the  raising 
of  water  by  suction  pumps,  the  air  in  the  pumps  being  removed  by  the  movement 
of  the  piston,  and  its  space  occupied  by  water  forced  up  by  the  pressure  of  the  outside 
atmosphere.  For  the  same  reason  such  a  pump  cannot  lift  water  higher  than  32  feet, 
a  column  of  water  of  this  height  exerting  nearly  the  same  pressure  as  the  atmosphere 
at  the  earth's  surface.  For  the  same  reason  the  mercury  in  a  barometer  (or  glass  tube 
from  which  the  air  is  withdrawn)  stands  about  29  inches  high,  varying  with  the  pres- 
sure of  the  atmosphere  between  27  and  30  inches  at  the  earth's  surface,  but  decreases 
with  the  height  above  the  earth  at  the  rate  of  0.1  inch  for  84  feet. 

Absolute  and  Gauge  Pressure. — The  pressure  gauges  in  general  use  indicate  pres- 
sure in  pounds  per  square  inch  above  the  atmospheric  pressure.  To  convert  gauge 
pressure  into  absolute  pressure  14.7  has  to  be  added  to  the  former.  Lighter  pressures 
are  designed  by  the  number  of  inches  of  mercury  which  they  will  sustain,  or  in  the 
metric  system  by  millimeters  of  mercury. 

190 


PHYSICAL   PROPERTIES   OF    GASES  191 

Weight  of  Gases. — The  weight  of  a  gas  is  determined  by  weighing  a  glass  balloon 
filled  with  the  same,  arid  by  subtracting  from  this  weight  that  of  the  balloon  after 
it  has  been  exhausted  by  means  of  an  air  pump.  One  hundred  cubic  inches  of  air 
weighs  31  grains  at  a  pressure  of  the  atmosphere  of  30  inches,  and  at  a  temperature 
of  60°  F.;  therefore  the  density  of  the  air  is  0.001293,  or  one  one  hundred  and  seventy- 
third  that  of  water.  One  hundred  cubic  inches  of  hydrogen,  the  lightest  of  the  com- 
mon gases,  weighs  2.14  grains. 

Mixture  of  Gases. — Two  or  more  gases  present  in  vessels  communicating  with 
each  other,  mix  readily,  and  each  portion  of  the  mixture  contains  the  different 
gases  in  the  same  proportion.  Mixtures  of  gases  follow  the  same  laws  as  simple 
gases. 

Critical  Temperature. — There  appears  to  exist  for  each  gas  a  temperature  above 
which  it  cannot  be  liquefied,  no  matter  what  amount  of  pressure  is  used.  It  is  called 
the  critical  temperature.  Below  this  temperature  all  gases  or  vapors  may  be  lique- 
fied if  sufficient  pressure  is  used. 

Critical  Volume. — The  critical  volume  of  a  gas  is  its  volume  at  the  critical  point, 
measured  with  its  volume  at  the  freezing  point,  under  the  pressure  of  an  atmosphere 
as  unit.  The  critical  temperature,  pressure,  and  volume  are  frequently  referred  to 
as  critical  data. 

Dalton's  Law. — The  pressure  exerted  on  the  interior  walls  of  a  vessel  containing 
a  mixture  of  gases  is  equal  to  the  sum  of  the  pressures  which  would  be  exerted  if  each 
of  the  gases  occupied  the  vessel  itself  alone. 

Critical  Pressure. — The  pressure  which  causes  liquefaction  of  a  gas  at  or  as 
near  below  the  critical  temperature  as  possible,  is  called  the  critical  pressure. 
Between  these  two  temperatures — that  is,  in  the  neighborhood  of  the  critical  point 
— the  transition  from  one  state  to  another  is  not  discernable. 

Buoyancy  of  Gases. — The  Archimedian  principle  applies  to  the  buoyancy  of 
gases;  hence  a  body  lighter  than  air  will  ascend  (air  balloons,  smoke,  etc.). 

Specific  Heat  of  Gases. — A  gas  may  be  heated  while  its  volume  is  kept  constant 
and  also  while  its  pressure  remains  constant.  In  the  former  case  the  pressure 
increases  and  in  the  latter  the  volume  increases;  therefore  we  make  a  distinction 
between  specific  heat  of  gases  at  a  constant  volume  and  at  a  constant  pressure.  In 
the  former  case  the  heat  added  is  only  used  to  increase  the  momentum  of  the 
molecules,  while  in  the  latter  case  an  additional  amount  of  heat  is  required  to  do 
the  work  of  expanding  the  gas  against  the  pressure  of  the  atmosphere.  The  specific 
heat  of  all  permanent  gases  for  equal  volumes  at  constant  pressure  is  nearly  the 
same,  and  equal  to  about  0.2374,  water  taken  as  unit. 

Heat  of  Compression.— When  gases  or  vapors  are  being  compressed,  the  energy 
or  work  spent  to  accomplish  the  compression  appears  in  the  form  of  heat. 

Adiabatic  Changes. — As  gas  is  said  to  be  expanded  or  compressed  adiabatically 
when  no  heat  is  added  or  abstracted  from  the  same  during  expansion  or  compres- 
sion, an  adiabatic  line  or  curve  represents  graphically  the  relations  of  pressure  and 
volume  under  such  conditions. 

Liquefaction  of  Gases. — If  sufficient  pressure  be  applied  to  a  gas,  and  the  tem- 
perature is  sufficiently  lowered,  all  gases  can  be  compressed  so  as  to  assume  the 
liquid  state. 


192  GAS   PRODUCERS 

Latent  Heat  of  Expansion.  —  When  a  gas  expands  while  doing  work,  such  as 
propelling  a  piston,  an  amount  of  heat  equivalent  to  the  work  done  becomes  latent 
or  disappears.  It  is  called  the  latent  heat  of  expansion. 

Perfect  Gas.  —  The  above  rules  and  formulae  apply,  strictly  speaking,  only  to  a 
perfect  or  ideal  gas,  that  is,  a  gas  in  which  the  dimensions  of  the  molecules  may  be 
neglected  as  regards  the  distance  between  them.  Therefore  when  a  gas  approaches 
the  state  of  a  vapor  these  rules  do  not  apply. 

Free  Expansion.  —  When  gas  expands  against  an  external  pressure  much  less 
than  its  own,  the  expansion  is  said  to  be  free.  The  refrigeration  due  to  the  work 
done  by  such  expansion  may  be  used  to  liquefy  air.  (Linde's  Method.) 

Volume  and  Pressure.  —  The  relation  of  volume,  pressure,  and  temperature  of 
gases  are  embodied  in  the  following  formulae  in  which  V  stands  for  the  initial 
volume  of  a  gas  at  the  initial  temperature  t  and  the  initial  pressure  p.  V,  t',  and 
p'  stand  for  the  corresponding  final  volume,  temperature,  and  pressure. 

For  different  temperatures, 


Z  +  461 
For  different  pressures, 

V'  =  V-. 

P 

For  different  temperatures  and  pressures, 

•     • 


If  the  initial  temperature  is  60°  F.  and  the  initial  pressure  that  of  the  atmosphere, 
the  final  pressure  may  be  found  after  the  formula, 


:    35.587' 
If  the  volume  is  constant, 

if  4 


. 
35.58 

If  the  temperatures  in  above  formula  are  expressed  in  degrees  Fahrenheit  above 
absolute  zero,  the  461  is  to  be  omitted. 

Isothermal  Changes. — A  gas  is  said  to  be  expanded  or  compressed  isothermally 
when  its  temperature  remains  constant  during  expansion  or  compression,  and  an 
isothermal  curve  or  line  represents  graphically  the  relations  of  pressure  and  volume 
under  such  conditions. 

Absolute  Zero. — The  expansion  of  a  perfect  gas  under  constant  pressure  being 
one  four  hundred  and  ninety-third  of  its  volume  per  degree  at  32°  F.,  it  follows 
that  if  a  perfect  gas  be  cooled  down  to  a  temperature  of  493°  below  freezing  or 


PHYSICAL   PROPERTIES    OF   GASES  193 

461°  below  zero  its  volume  will  become  zero.  Hence  this  point  is  adopted  as  the 
absolute  zero  of  temperature. 

Absorption  of  Gases. — Gases  are  absorbed  by  liquids;  the  quantities  of  gases  so 
absorbed  depend  upon  the  nature  of  the  gas  and  liquid,  and  generally  increase  with 
the  pressure  and  decrease  with  the  temper.ature.  During  the  absorption  of  gas  by 
a  liquid  a  definite  amount  of  heat  is  generated,  which  heat  is  again  absorbed  when 
the  gas  is  driven  from  the  liquid  by  increase  of  temperature  or  decrease  of  pressure. 
Solids,  especially  porous  substances,  also  absorb  gases.  Thus  charcoal  absorbs  ninety 
times  its  own  volume  of  ammonia  gas. 

Velocity  of  Sound. — The  velocity  V  of  sound  in  gases  is  expressed  by  the  formula 


In  which  formula  g  is  the  force  of  gravity,  h  is  the  barometric  height,  D  the  density 
of  mercury,  d  the  density  of  the  gas,  t  its  temperature,  c  its  specific  heat  at  constant 

£ 

pressure,  c'  its  specific  heat  at  constant  volume.     Hence  the  quotient  —  for  a  certain 

C 

gas  can  be  determined  by  the  velocity  of  sound  in  the  same. 

Friction  of  Gas  in  Pipes. — The  loss  of  pressure  in  pounds  P  sustained  by  gas  in 
traveling  through  a  pipe  having  the  diameter  d  in  inches,  for  a  distance  of  /  feet, 
and  having  a  velocity  of  n  feet  is 

n2l 

P  =  0.00936—. 
d 

Properties. — One  authority  compiles  the  following  characteristics  of  gases  usually 
met  in  metallurgical  calculations. 

CARBONIC   ACID   OR   CARBON    DIOXIDE 

Formula C02 

Composition  by  weight 73. 7%  O,  27.3%  C 

Density  or  specific  gravity,  air  =  1 1 . 529 

Pounds  per  cubic  foot 116 

Cubic  feet  per  pound 8 . 62 

Cubic  feet  air  necessary  to  consume  1  cu.ft Non-combustible 

B.T.U.  per  cubic  foot Non-combustible 

Solubility:  Volumes  absorbed  in  1  volume  water.  .  .      1.23 

ILLUMINANTS   OR   HEAVY    HYDROCARBONS 

Formula 90%  C2H4 

Composition  by  weight 85. 7%  C,  14.3%  H 

Density  or  specific  gravity,  air  =  1 985 

Pounds  per  cubic  foot 074 

Cubic  feet  per  pound 13 . 38 

Cubic  feet  air  necessary  to  consume  1  cu.ft 14.34 

B.T.U.  per  cubic  foot 1675 

Solubilitv:  Volumes  absorbed  in  1  volume  water.  .          .15 


194  GAS   PRODUCERS 

OXYGEN 

Formula 0 

Composition  by  weight 100%  O 

Density  or  specific  gravity,  air  =  1 1. 105 

Pounds  per  cubic  foot 084 

Cubic  feet  per  pound 1 1 . 94 

Cubic  feet  air  necessary  to  consume  1  cu.ft Non-combustible 

B.T.U.  per  cubic  foot Non-combustible 

Solubility:  Volumes  absorbed  in  volume  water 028 

CARBONIC   OXIDE   OR   CARBON   MONOXIDE 

Formula CO 

Composition  by  weight 42.9%  C,  57. 1%  O 

Density  or  specific  gravity,  air=  1 967 

Pounds  per  cubic  foot 073 

Cubic  feet  per  pound 1 3 . 57 

Cubic  feet  air  necessary  to  consume  1  cu.ft 2 . 39 

B.T.U.  per  cubic  foot 341 

Solubility :  Volumes  absorbed  in  1  volume  water ...        .  023 

HYDROGEN 

Formula H 

Composition  by  weight 100%  H 

Density  or  specific  gravity,  air  =  1 069 

Pounds  per  cubic  foot 006 

Cubic  feet,  pounds 189 . 23 

Cubic  feet  air  necessary  to  consume  1  cu.ft 2.39 

B.T.U.  per  cubic  foot 345 

Solubility:  Volumes  absorbed  in  1  volume  water.  .  .        .019 

METHANE   OR   MARSH   GAS 

Formula CH4 

Composition  by  weight 75%  C,  25%  H 

Density  or  specific  gravity,  air  =  1 556 

Pounds  per  cubic  foot 0422 

Cubic  feet  per  pound 23 . 72 

Cubic  feet  air  necessary  to  consume  1  cu.ft 9.56 

B.T.U.  per  cubic  foot 1065 

Solubility:  Volumes  absorbed  in  1  volume  water.  .  .        .035 

NITROGEN 

Formula N 

Composition  by  weight 100%  N 

Density  or  specific  gravity,  air  =  l 971 

Pounds  per  cubic  foot 073 

Cubic  feet  per  pound 13.57 

Cubic  feet  of  air  necessary  to  consume  1  cu.ft Non-combustible 

B.T.U.  per  cubic  foot Non-combustible 

Solubility:  Volumes  absorbed  in  1  volume  water.  .  .        .015 


PHYSICAL   PROPERTIES   OF   GASES  195 

ACETYLENE 

Formuia CH2 

Composition  by  weight 93.3%  C,  7.7%  H 

Density  or  specific  gravity,  air  =  1 918 

Pounds  per  cubic  foot 069 

Cubic  feet  per  pound 14 . 32 

Cubic  feet  air  necessary  to  consume  1  cu.ft 11.91 

B.T.U.  per  cubic  foot 1600 

Solubility:  Volumes  absorbed  in  1  volume  water.  .  .      1.11 

AIR 

Formula Mixture  O  and  N 

Composition  by  weight 77%  N,  23%  O 

Density  or  specific  gravity,  air  =  1 1 . 000 

Pounds  per  cubic  foot .  076 

Cubic  feet  per  pound 13.15 

Cubic  feet  air  necessary  to  consume  1  cu.ft Non-combustible 

B.T.U.  per  cubic  foot Non-combustible 

Solubility:  Volumes  absorbed  in  1  volume  water.  .  .  .017 

Properties  of  Vapors. — As  long  as  a  volatile  substance  is  above  its  critical 
temperature  it  is  called  a  gas,  and  if  below,  it  is  called  a  vapor.  This  definition, 
although  the  most  definite,  is  not  the  most  popular  one.  Frequently  a  vapor  is 
defined  as  representing  that  gaseous  condition  at  which  a  substance  has  the  maxi- 
mum density  for  that  temperature  or  pressure.  Generally  gaseous  bodies  are  called 
vapors  when  they  are  near  the  point  of  their  maximum  density,  and  a  distinction 
is  made  between  saturated  vapor,  superheated  vapor,  and  wet  vapor. 

Dalton's  Law  for  Vapors. — The  tension  and  consequently  the  amount  of  vapor 
of  a  certain  substance  which  saturates  a  given  space  is  the  same  for  the  same 
temperature,  whether  this  space  contains  a  gas  or  is  a  vacuum.  The  tension  of 
the  mixture  of  a  gas  and  a  vapor  is  equal  to  the  sum  of  the  tensions  which  each 
would  possess  if  it  occupied  the  same  space  alone. 

Dissociation. — The  term  dissociation  is  used  to  denote  the  separation  of  a 
chemical  compound  into  its  constituent  parts,  especially  if  the  separation  is  brought 
about  by  subjecting  the  compound  to  a  high  temperature. 

Vaporization. — A  liquid  exposed  to  the 'atmosphere  or  to  a  vacuum  forms  vapors 
until  the  space  above  the  liquid  contains  vapor  of  the  maximum  density  for  the 
temperature. 

Tension  of  Vapors. — Like  gases  vapors  have  a  certain  elastic  force,  by  virtue  of 
which  they  exert  a  certain  pressure  on  surrounding  surfaces.  This  elastic  force 
varies  with  the  nature  of  the  liquid  and  the  temperature,  and  is  also  called  the 
tension  of  the  vapor. 

Elevation  of  Boiling-point. — Substances  held  in  solution  by  liquids  raise  their 
boiling-point.  Thus  a  saturated  solution  of  common  salt  boils  at  214°  F.  and  one 
of  chloride  of  calcium  at  370°  F.  Water  may  be  caused  to  boil  at  a  much  higher 
temperature  than  the  one  indicated  by  the  normal  boiling-point,  so  water  free  from 


196  GAS   PRODUCERS 

gases  may  be  heated  to  over  260°  F.  without  showing  signs  of  boiling.  This  retard- 
ation of  boiling  sometimes  takes  place  in  boilers,  and  may  cause  explosions  if  not 
guarded  against  by  a  timely  agitation  produced  in  the  water. 

Sublimation. — The  change  of  a  solid  to  the  vaporous  state  without  first  passing 
through  the  liquid  state  is  called  sublimation.  Camphor,  ice,  or  snow  will  subli- 
mate in  this  manner. 

Different  Boiling-points. — The  boiling-point  varies  with  the  nature  of  the  liquid, 
and  always  increases  with  the  pressure.  It  is  not  affected  by  the  temperature  of 
the  source  of  heat,  the  temperature  of  the  liquid  remaining  constant  as  long  as 
ebullition  takes  place.  The  heat  which  is  imparted  to  a  boiling  liquid,  but  which 
does  not  show  itself  by  an  increase  of  temperature,  is  called  the  latent  heat  of 
vaporization. 

Vapors  from  Mixed  Liquids. — The  tension  of  vapor  from  mixed  liquids  (which 
have  no  chemical  or  solvent  action  on  each  other)  is  nearly  equal  to  the  sum  of 
tension  of  the  vapor  of  the  two  separate  liquids. 

Dry  or  Superheated  Vapor. — Vapors  which  are  not  saturated  are  also  called  dry 
or  superheated  vapors,  and  behave  like  permanent  gases. 

Liquefaction  of  Vapors. — When  vapors  pass  from  the  aeriform  to  the  liquid  state, 
that  is  when  they  are  liquefied,  the  heat  which  becomes  latent  during  evaporation, 
appears  again,  and  must  be  removed  by  cooling.  Vapors  of  liquids,  the  boiling- 
point  of  which  is  above  the  ordinary  temperature,  can  be  liquefied  at  the  ordinary 
temperature  without  additional  pressure  (distilling,  condensation).  Permanent  gases 
require  additional  pressure  and  in  some  cases  considerable  refrigeration,  to  become 
liquefied  (compression  of  gases). 

Boiling-point. — The  temperature  at  which  ebullition  of  a  liquid  takes  place  is 
called  its  boiling-point  for  the  pressure  then  obtaining.  When  no  special  pressure 
is  mentioned  we  understand  by  boiling-point  that  temperature  at  which  liquids  boil 
under  the  pressure  of  the  atmosphere. 

Refrigerating  Effects. — If  liquids  possess  a  boiling-point  below  the  temperature 
of  the  atmosphere  the  latent  heat  of  vaporization  is  drawn  from  its  immediate 
surroundings  causing  a  reduction  of  temperature,  i.e.,  refrigeration. 

Latent  Heat  of  Vaporization. — The  heat  which  becomes  latent  during  the  process 
of  volatilization  is  composed  of  two  distinct  parts.  The  one  part  is  absorbed  while 
doing  the  work  of  disintegrating  the  molecular  structure  while  doing  internal  work, 
as  it  is  termed.  The  other  part  of  heat,  which  becomes  latent,  is  absorbed  by 
doing  the  work  of  expansion  against  the  pressure  of  the  atmosphere,  and  is  called 
the  external  work.  In  a  liquid  vaporized  in  vacuum,  in  which  case  no  pressure  is 
to  be  overcome,  the  external  work  becomes  zero,  and  only  heat  is  absorbed  to  do 
the  internal  work  of  vaporization  (free  expansion). 

Ebullition. — If  the  temperature  is  high  enough  the  vaporization  takes  place 
throughout  the  liquid  by  the  rapid  production  of  bubbles  of  vapor.  This  is  called 
ebullition,  and  the  temperature  at  which  it  takes  place  is  a  constant  one  for  one 
and  the  same  liquid  under  a  given  pressure. 

Saturated  Vapor. — A  vapor  is  saturated  when  it  is  still  in  contact  with  some  of 
its  liquid;  vapors  in  the  saturated  state  are  at  their  maximum  density  for  that 
temperature.  Compression  of  a  saturated  vapor,  without  change  of  temperature, 


197 

produces  a  proportionate  amount  of  liquefaction.  But  if  the  temperature  rises 
correspondingly  to  the  work  done  by  the  compression,  or  partially  so,  it  becomes 
superheated. 

General  Laws.  —  Temperature.  —  The  weight  of  dry  .air  at  32°  F.  and  atmospheric 
pressure  (14.7  Ibs.  per  square  inch)  is  0.0807  Ibs.  per  cubic  foot;  from  which  the 
volume  of  one  pound  =  12.  4  cu.ft.  At  other  temperatures  and  pressures  its  weight 

1.325X5 
in  pounds  per   cubic   feet  is    W=—  -  -  --  ,   in   which   B  =  reading  of  barometer  in 

4oy.Z  ~r  t 

inches  and  t  =  temperature  F. 

The  absolute  zero  of  temperature  on  the  Fahrenheit  scale  is  492°  below  32°,  or 
-460°  F.  The  absolute  temperature  then  is  obtained  by  adding  460°  to  the  tem- 
perature as  read  from  the  Fahrenheit  scale.  Thus  60°  F.  =60°  +  460°  =  520°  absolute; 
and  -20°  F.  -  -20°  +460°  =  440°  absolute. 

Mechanical  Equivalent  of  Heat.  —  Heat  energy  and  mechanical  energy  are 
mutually  convertible,  that  is,  a  unit  of  heat  requires  for  its  production,  and  produces 
by  its  disappearance,  a  definite  amount  of  mechanical  energy,  namely,  778  ft.  -Ibs. 
of  work  for  each  British  thermal  unit. 

Pressure.  —  Boyle's  law  states  that  the  product  of  the  pressure  and  volume  of  a 
portion  of  gas  is  constant  so  long  as  the  temperature  is  constant,  that  is,  pv  =  c  in 
which  p  =  pressure  in  pounds  per  square  foot  and  v  =  volume  in  cubic  feet.  For 
air  at  32°  F.,  this  constant  quantity  is  26,200  ft.-lbs.,  or  pv  =  26,200  ft.-lbs. 

Charles'  and  Gay-Lussac's  law  states  that  when  the  pressure  is  constant  all 
gases  expand  alike  for  the  same  increase  of  temperature.  The  amount  of  this  expan- 
sion between  32°  and  212°  F.  is  0.365  of  the  original  volume;  and  for  each  degree 
it  equals  0.365-^180  =  0.00203.  Similiarly,  when  the  volume  remains  constant  the 
pressure  varies  in  the  above  ratio. 

Combining  Boyle's  and  Charles'  laws  we  see  that  the  product  of  the  pressure 
and  volume  of  a  portion  of  gas  is  proportional  to  the  absolute  temperature.  Thus, 

pv      T 

-  =  —  ,  in  which  p  and  pi=  absolute  pressures  (that  is,  pressures  above  a  vacuum) 


in  pounds  per  square  foot;    v  and  Vi=  volumes  in  cubic  feet;    T  and  TI=  absolute 
temperatures. 

Transforming  the  above  equation  and  substituting  32  for  T\  and  26,200  fo 
we  get 


The  specific  heat  of  a  gas  is  the  quantity  of  heat  in  heat  units  necessary  to 
raise  the  temperature  of  one  pound  of  the  gas  through  one  degree  of  temperature. 

The  specific  heat  of  air  is  at  constant  pressure,  cp  =  0.238,  and  at  constant  volume, 
c»  =  0.169  B.T.U. 

Adiabatic  expansion  or  compression  of  a  gas  means  that  the  gas  is  expanded  or 
compressed  without  transmission  of  heat  to  or  from  the  gas.  This  would  be  the  case 
were  the  expansion  or  compression  to  take  place  in  an  absolutely  non-conducting 


198  GAS    PRODUCERS 

cylinder,  in  which  case  the  temperature,  pressure,  and  vomme  would  vary  as  indicated 
by  the  following  formulae: 


_ 

PJ        '      2*1  w 


2-46  P2          T      3  46 


in  which  pi,  v\,  and  TI=  initial  absolute  pressure,  volume,  and  absolute  tempera- 
ture, and  p2,  v2,  and  T%  final  absolute  pressure,  volume,  and  absolute  tempera- 
ture of  the  gas. 

Isothermal  expansion  or  compression  of  a  gas  means  that  the  gas  is  expanded 
or  compressed  with  the  addition  or  rejection  of  sufficient  heat  to  maintain  the 
temperature  constant.  In  this  case,  the  temperature  being  constant,  the  pressure 
and  volume  will  vary  according  to  Boyle's  law,  namely, 


in  which  p  =  absolute  pressure  in  pounds  per  square  foot,  v  =  volume  in  cubic  feet,. 
and  (7  =  a  constant  depending  upon  the  temperature.  For  a  temperature  of  32°  F. 
this  constant  is  26,200  ft.-lbs.,  and  for  isothermals  corresponding  to  other  tempera- 
tures it  may  be  found  from  the  formula  C  =  53.2  T,  in  which  T  =  the  absolute  tem- 
perature of  the  isothermal. 

Combined  compression  of  air  is  compression  under  conditions  that  permit  of 
some  withdrawal  of  heat  during  compression,  but  not  sufficient  to  keep  the  tempera- 
ture of  the  air  constant.  In  this  case  the  compression  curve  lies  between  the 
isothermal  and  adiabatic  curves,  and  the  relation  of  pressure  to  volume  may  be 
expressed  by  the  formula, 


in  which  p  =  absolute  pressure  in  pounds  per  square  foot;  v  =  volume  in  cubic  feet; 
(7  =  a  constant;  and  n  =  an  exponent  whose  value  may  vary  from  1,  that  for  isothermal, 
to  1.41,  that  for  adiabatic  compression  or  expansion. 

Constant  Pressure  and  Constant  Volume.  —  The  terms  "  constant  pressure  "  and 
"  constant  volume  "  mean,  as  their  nomenclature  would  indicate,  that  if  a  gas  is 
heated  and  not  allowed  to  expand,  the  pressure  will  rise  very  rapidly.  The  volume 
is  constant,  that  is,  unchanged,  and  the  heat  produces  more  energy  in  the  gas, 
which  is  reflected  in  pressure.  In  this  manner  steam  may  by  its  pressure  burst  a 
boiler  if  confined  without  relief  and  heat  increased. 

If,  again,  a  gas  is  heated  and  kept  at  the  same  pressure  the  heat  will  cause  an 
increase  in  volume.  The  pressure  is  constant  and  does  not  change,  but  in  this, 


PHYSICAL   PROPERTIES    OF   GASES  1991 

instance  the  volume  changes  since  the  heat  forces  the  molecules  further  apart. 
The  energy  of.  the  heat  expends  itself  partly  in  increasing  the  volume  of  the  gas. 

Less  heat  is  required  to  raise  the  temperature  of  a  gas  while  under  pressure  than 
is  required  if  allowed  to  expand,  that  is,  the  specific  heat  of  a  gas  is  less  at  constant 
volume  than  at  constant  pressure. 

Ordinarily  considered,  a  gas  is  usually  taken  at  constant  volume  for  purposes 
of  calculation,  although  in  furnace  work  or  reactions  involving  heat  the  calculation 
is  usually  made  at  constant  pressure. 

Density.  —  The  density  of  elementary  gases  are  directly  proportional  to  their 
atomic  weights.  The  density  of  a  compound  gas  referring  to  hydrogen  as  one,  is 
one-half  its  molecular  weight.  Thus  the  relative  density  of  C02  is  ^(12  +  32)  =22. 

To  find  the  weight  of  a  gas  Jn  pounds  per  cubic  foot  at  32°  F.  multiply  one-half 
the  molecular  weight  of  the  gas  by  0.00559.  Thus  one  cubic  foot  of  marsh  gas 
CH4  =  i(12  +  4)  X  0.00559  =  0.0447  pounds. 

Voluire  Conversion.  —  Gases  increase  directly  in  volume  with  their  tempera- 
ture (starting  at  0°  C.),  one  two  hundred  and  seventy-  third  for  each  degree  C. 
or  one  four  hundred  and  ninetieth  above  32°  F.  (about  1%  for  each  5°  F.),  that 
is  to  say,  at  273°  C.  the  volume  is  just  double  that  at  0°  C.  and  at  522°  F.  double 
that  at  32°  F. 

The  volume  of  a  gas  is  directly  proportional  to  its  absolute  temperature,  its 
density  inversely  proportional  to  its  absolute  temperature.  To  calculate  .we  have 
T^-^Ti  =  V.  TI  equals  absolute  temperature  at  normal  or  standard  conditions  \ 
T2  equals  the  absolute  temperature  to  which  the  sensible  temperature  is  increased. 

As  the  volume  increases  with  temperature,  the  larger  of  the  two  factors  must 
necessarily  constitute  the  enumerator  and  the  lower  the  denomination  or  the 
fraction  or  vice  versa;  for  example,  100  cubic  feet  of  a  gas  at  10°  C.,  raised  to 
60°  C.,  to  find  the  volume: 

60  +  273     333 


Again,  take  100  cubic  feet  at  40°  F.,  raised  to  60°  C.,  to  find  the  volume: 
60-32+490 


60-32  +  490 


X 100  =  V  cu.ft.  at  60°  F. 


To  reduce  observed  volumes  to  those  at  absolute  standard  pressure  and  tem- 
perature Dawson  and  Larter  present  the  following  discussion: 

(a)  At  a  given  temperature,  the  volume  of  a  given  mass  of  gas  is  inversely 
proportional  to  its  pressure. — (Boyle's  Law.) 

(fe)  At  a  given  pressure,  the  volume  of  a  given  mass  of  gas  is  directly  propor- 
tional to  its  absolute  temperature. — (Charles'  Law.) 

Hence  if  V\  be  the  volume  of  a  given  mass  of  gas  at  pressure  PI  and  absolute 


200  GAS   PRODUCERS 

temperature  Tlf  and  if  V0  be  the  volume  which  the  gas  would  occupy  at  some  other 
pressure  P0  and  absolute  temperature  T0,  then 


T,          To  ' 

P      T 

and  therefore  Fn  =  Fi  X  —  X  — 

p          T   ' 

"o     1  1 

The  reduction  of  the  volume  of  a  gas  to  the  standard  temperature  and  pressure 
is  done  as  follows: 

Unless  otherwise  stated,  the  volume  of  a  gas  means  the  volume  it  would  occupy 
under  the  standard  conditions  of  temperature  and  pressure,  viz.,  0°  C.  (32°  F.)  and 
760  mm.  (29.92  inches)  of  mercury. 

If  FI  be  the  observed  volume  of  the  gas,  measured  at  a  temperature  ti°  C.  and 
under  a  pressure  PI  mm.  of  mercury,  the  reduced  volume  (i.e.,  the  volume  which 
the  gas  would  occupy  at  the  standard  temperature  and  pressure)  is 

PI         273 


760 

If  FI  be  the  observed  volume  of  the  gas,  measured  at  a  temperature  of  /i°  F. 
and  under  a  pressure  PI  inches  of  mercury,  the  reduced  volume  is 

v  -v       Pl        49L4 

29~.92     ti  +459.4' 

When  a  gas  is  measured  over  water  (e.g.,  in  a  gasholder  or  by  a  wet  meter)  it 
is  saturated  with  aqueous  vapor.  The  actual  pressure  PI  of  the  gas  is  the  observed 
pressure  minus  the  maximum  pressure  of  aqueous  vapor  at  the  temperature  of  the 
gas. 

Required  the  weight  of  a  cubic  meter  of  hydrogen  at  1000°  C.  and  250  mm. 
pressure,  its  weight  (volume  X  specific  gravity)  at  standard  conditions  being  0.09  kg. 
Example : 


Tension  of  Aqueous  Vapor. — According  to  Wyer  as  the  vaporization  of  the 
moisture  in  fuel,  and  the  destructive  distillation  of  the  fuel,  always  produce  steam 
or  water  vapor,  it  is  nearly  always  found  in  producer  gas.  Above  the  boiling-point 
corresponding  to  the  pressure  of  the  gas,  all  the  water  will  be  in  the  vapor  state; 
below  this  point,  part  of  the  steam  will  condense,  but  a  certain  amount  of  water 
will  always  remain  in  the  gas.  Water  vapor,  on  account  of  its  high  specific  heat, 
may  cause  a  large  heat  loss  in  the  products  of  combustion. 

Air  consists  of  a  mixture  of  oxygen  and  nitrogen  with  very  small  quantities  of 
other  substances,  such  as  argon,  ammonia,  carbon  dioxide,  and  water  vapor,  the 
amount  of  the  latter  depending  upon  the  temperature  and  relative  humidity  of  the 
atmosphere.  The  amounts  of  argon,  ammonia,  and  carbon  dioxide  are  so  small  that 


PHYSICAL   PROPERTIES    OF   GASES 


201 


they  need  never  be  considered.     Pure  dry  air  is  composed  of  20.91  parts  0  and  79.09 
parts  N  by  volume,  or  23.15  parts  O  and  76.85  parts  N  by  weight. 


X  -T-  0 By  volume 


79.09 
2O9T 

100 


Air  -7-0  .......   By  volume  =4.78. 


100 

By  volume  --  =  1.265. 
i  y  .uy 


76.85 

By  weight  -     -  =  3.32. 
23.15 

100 

By  weight  -     -  =  4.315. 
23.15 

100 
By  weight  ——=1.302. 


AMOUNT  OF  MOISTURE  TO  100  LBS.   OF  DRY  AIR  WHEN   SATURATED  AT   DIFFER- 
ENT TEMPERATURES.— (SIEBEL.) 


Temperature, 
Degrees  F. 

Aqueous  Vapor, 
Pounds. 

Temperature, 
Degrees  F. 

Aqueous  Vapor, 
Pounds. 

Temperature, 
Degrees  F. 

Aqueous  Vapor, 
Pounds. 

-20 

0.0350 

62 

1.179 

142 

16  .  170 

-10 

0.0574 

72 

1.680 

152 

22.465 

0 

0.0918 

89 

2.361 

162 

31.713 

+  10 

0.1418 

92 

3.289 

172 

46.338 

20 

0.2265 

102 

4.547 

182 

71.300 

32 

0.379 

112 

6.253 

192 

122.643 

42 

0.561 

122 

8.584 

202 

280  .  230 

52 

0.918 

132 

11.771 

212 

Infinite 

Water  Vapor. — In  calculations  of  gases  the  tension  of  water  vapor  for  the 
temperature  observed  must  be  found  from  tables  containing  these  tensions  for  the 
different  temperatures,  such  as  the  following: 

TENSION  OF  AQUEOUS  VAPOR  IN  INCHES  OF  MERCURY 


Temperature, 
Degrees  F. 

Inches  of 
Mercury. 

Temperature, 
Degrees  F. 

Inches  of 
Mercury. 

Temperature, 
Degrees  F. 

Inches  of 

Mercury. 

40 

0.247 

57 

0.465 

74 

0.840 

41 

0.257 

58 

0.482 

75 

0.868 

42 

0.267 

59 

0.500 

76 

0.897 

43 

0.277 

60 

0.518 

77 

0.927 

44 

0.288 

61 

0.537 

78 

0.958 

45 

0.299 

62 

0.556 

79 

0.990 

46 

0.311 

63 

0.576 

80 

1.023 

47 

0.323 

64 

0.596 

81 

1.057 

48 

0.335 

65 

0.617 

82 

1.092 

49 

0.348 

66 

0.639 

83 

1.128 

50 

0.361 

67 

0.661 

84 

1.165 

51 

0.374 

68 

0.685 

85 

1.203 

52 

0.388 

69 

0.708 

86 

1.242 

53 

0.403 

70 

0.733 

87 

1.282 

54 

0.418 

71 

0.759 

88 

1.323 

55 

0.433 

72 

0.785 

89 

1.356 

56 

0.449 

73 

0.812 

90 

1.401 

202 


GAS   PRODUCERS 


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GAS   PRODUCERS 


TENSION  OF  AQUEOUS  VAPOR  (METRIC) 


Degrees 
Centigrade. 

Tension  in 
Millimeters  of 
Mercury 

Degrees 
Centigrade. 

Tension  in 
Millimeters  of 
Mercury. 

Degrees 
Centigrade. 

Tension  in 
Millimeters  of 
Mercury. 

-20 

0.927 

6.6 

7.292 

15.6 

13.197 

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2.093 

6.8 

7.392 

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13.366 

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3.955 

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4.078 

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16.4 

13.885 

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4.140 

7.6 

7.840 

16.6 

14.062 

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4.203 

7.8 

7.910 

16.8 

14.241 

-    1. 

4.267 

8. 

8.017 

17. 

14.421 

-   0.8 

4.331 

8.2 

8.126 

17.2 

14.605 

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4.397 

8.4 

8.236 

17.4 

14.790 

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4.463 

8.6 

8.347 

17.6 

14.977 

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4.531 

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9.6 

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5.4 

6.717 

14.4 

12.220 

23.4 

21.400 

5.6 

6.810 

14.6 

12.378 

23.6 

21.659 

5.8 

6.904 

14.8 

12.538 

23.8 

21.921 

6. 

6.998 

15. 

12.699 

24. 

22  .  184 

6.2 

7.095 

15.2 

12.864 

24.2 

22.453 

6.4 

7.193 

15.4 

13.029 

24.4 

22.723 

PHYSICAL   PROPERTIES  OF   GASES 


205 


TENSION   OF  AQUEOUS  VAPOR— (Continual) 


f.                                   Tension  in 
Degrees                   Millimeters  of 
Centigrade                     Mercury. 

T-.                                 Tension  in 
cSSe.               »<3£S« 

Degrees 
Centigrade. 

Tension  in 
Millimeters  of 
Mercury. 

24.6 

22.996 

29.8 

31.190                     99.8 

754  .  57 

24.8 

23.273 

30. 

31.548 

99.9 

757.28 

25. 

23.550 

31. 

33.405 

100. 

760. 

2f>  .  •_> 

23.834 

32. 

35.359 

100.1 

762.73 

25.4 

24.119 

33. 

37.410 

100.2 

765.46 

25.6 

24.406 

34. 

39.565 

100.3 

768.20 

25.8 

24.607 

35. 

41.827 

100.4 

771.95 

26. 

24.988 

40. 

54.906 

100.5 

773.71 

26.2 

25.288 

45. 

71.391 

100.6 

776.48 

26.4 

25.88 

50. 

91.982 

100.7 

779.26 

26.6 

25.891 

55. 

117.478 

100.8 

782.04 

26.8 

26  .  198 

60. 

148.791 

100.9 

784.83 

27. 

26  .  505 

65. 

186.945 

101. 

787.63 

27.2 

26.820 

70. 

233.093 

105. 

960.41 

27.4 

27.136 

75. 

288.517 

110. 

1075.37 

27.6 

27.455 

80. 

354.643 

120. 

1491.28 

27.8 

27.778 

85. 

433.041 

130. 

2030.28 

28. 

28  .  101 

90. 

525.450 

140. 

2717.63 

28.2 

28.433 

95. 

633.778 

150. 

3581.23 

28.4 

28.765 

99. 

733.21 

160. 

4651.62 

28.6 

29  .  101 

99.1 

738.5 

170. 

5961.66 

28.8 

29.441 

99.3 

741.16 

180. 

7546.39 

29. 

29.782 

99.4 

743.83 

190. 

9442.70 

29.2 

30.131 

99.5 

746.5 

200. 

11688.96 

29.4 

30.479 

99.6 

749  .  18 

220. 

17390  . 

29.6 

30.833 

99.7 

751  .87 

224.7 

25 

atmos. 

Ignition  Temperature  of  Gaseous  Mixtures. — As  a  matter  of  fact,  for  reasons 
unknown  to  the  writer,  pre-ignition  in  gas  engines  will  be  found  to  occur  from 
any  variation  in  the  calorific  value  of  the  gas  or  in  its  analysis.  This  may  be  due 
either  to  conditions  of  stagnation,  conditions  of  heat  propagation,  or  to  unknown 
chemical  reactions  of  the  explosive  mixture.  Suffice  it  that  such  is  an  observed 
phenomena. 

Professor  K.  G.  Falk  has  made  some  exceedingly  valuable  researches  in  the 
matter  of  ignition  temperature  of  gaseous  mixtures,  presenting  them  from  time  to 
time  before  the  American  Chemical  Society.  His  most  successful  method  has  been 
the  adiabatic,  wherein  he  experimented  through  the  compressing  of  gas  by  means  of  a 
piston  and  airtight  cylinder. 

Extracts  of  some  of  his  results  are  herewith  noted: 


206  GAS   PRODUCERS 


IGNITION   TEMPERATURES 

HYDROGEN   AND   OXYGEN 

Reaction.  T2- 

4H2  +  O2 878 

2H2  +  02 813 

H2  +  02 787 

H2  +  2O2 803 

H2  +  402 844 

CARBON   MONOXIDE  AND   OXYGEN 

Reaction.  T2. 

6CO  +  O2 994 

4CO  +  O2 901 

2CO  +  O2 874 

CO  +  O2 904 

HYDROGEN,   OXYGEN,   AND   NITROGEN 

Reaction.  T2  (obs.)  T  (calc.). 

820  817 

851  847 

910  907 

2H2  +  O2  +  N2 846  843 

2H2  +  O2+4N2 922  933 

H2  +  202  +  N2 837  833 

H2  +  2O2  +  4N2 914  923 

CARBON   MONOXIDE,   OXYGEN,   AND   NITROGEN 
Reaction.  T2  (obs.).          T  (calc.). 

2CO  +  O2  +  N2 917  914 

2CO  +  02  +  2N2 958  954 

979  984 

+  2N2 1085      1064 

4CO  +  O2  +  N2 925  921 

4CO  +  O2  +  2N2 ..940  941 

HYDROGEN,   CARBON   MONOXIDE,   AND   OXYGEN 
Reaction.  T  (obs.).  Ta  (calc.).        Tb  (calc.). 

H2  +  O2+CO 812  817  984 

H2  +  O2+2CO 851  847  914 

+  4CO 898  907  921 

877       873  954 

938       933  941 

H2  +  2O2  +  2CO 869  863  944 

H2  +  2C02  +  4CO 888  923  894 

+  2CO.  .   825  822  1030 


PHYSICAL   PROPERTIES   OF   GASES 


207 


Although  there  has  been  a  considerable  amount  of  work  done  on  the  deter- 
mination of  the  ignition  temperatures  of  mixtures  of  hydrogen  and  oxygen,  there 
has  been  comparatively  little  with  mixtures  of  other  gases.  V.  Meyer  and  Krause 
found  the  ignition  temperature  of  the  mixture  2CO  +  O9  to  lie  between  791°  and 
879°  absolute,  using  the  method  of  enclosing  the  mixture  in  sealed  bulbs,  which 
were  plunged  into  baths  heated  to  definite  temperatures.  They  found  the  same 
ignition  temperature  for  the  mixture  2H2  +  O2.  Mallard  and  Le  Chatelier,  by  passing 
the  gas  into  a  tube  heated  to  a  definite  temperature,  found  the  ignition  tempera- 
ture of  the  mixture  containing  70%  carbon  monoxide  and  30%  oxygen  to  be  about 
923°.  They  also  found  that  diluting  this  mixture,  as  well  as  the  detonating  gas 
mixture,  with  one  of  the  active  constituents  or  with  an  inert  gas,  modified  the 
ignition  temperature  only  slightly. 

Calorific  Power. — The  heat  value  of  a  gas  depends  upon  whether  the  water 
formed  by  combustion  is  or  is  not  condensed,  the  latter  giving  the  net  value,  as 
shown  in  the  following  tables: 

CALORIFIC  POWER  OF  GASES  (BURNT  AT  CONSTANT  PRESSURE) 


Gas. 

Calorific  Power. 

Calories  per  Kilo. 

B.T.U.  per  Pound. 

Calories  per  Cubic 
Meter. 

B.T.U.  per  Cubic 
Foot. 

Higher 
Value. 

Lower 
Value. 

Higher 
Value. 

Lower 
Value. 

Higher 
Value. 

Lower 
Value. 

Higher 
Value. 

Lower 
Value. 

Carbon  monoxide  

2,4362 
12,1822 
34,5002 
13,3442 

4,385 

3,046 
15,239 
3,088 
9,541 

342.4 
1713.0 
347.1 
1072.0 

Ethylene.         .    .    . 

11,404 
29,050 
11,981 

21,928 
62,100 
24,019 

20,527 
52,290 
21,566 

14,266 
2,601 
8,567 

1603.0 
292.3 
963.0 

Hydrogen  

Methane.          

Carbon  

81,375 

146,475 

1  calorie  per  kilo  =  1.8  B.T.U.  per  pound. 

1  B.T.U.  per  pound  =0.555  calorie  per  kilo. 

1  calorie  per  cubic  meter  =  0.1124  B.T.U   per  cubic  foot. 

1  B.T.U.  per  cubic  foot    =8.900  calories  per  cubic  meter. 


If  the  combustion  is  accompanied  by  a  change  in  volume  the  calorific  powers 
at  constant  pressure  and  at  constant  volume  will  be  different. 

Let  n\  be  the  number  of  molecular  volumes  (22.32  cm.)  of  the  gas  together 
with  the  oxygen  required  for  its  combustion,  and  let  712  be  the  number  of  molecular 
volumes  of  the  products  of  combustion. 

The  n1—n2  is  the  change  in  volume,  and  the  work  done  by  or  against  the 
pressure  of  the  atmosphere  is  equivalent  to  54lX(fti  —  n2)  calories. 

The  nitrogen  in  the  air  used  for  combustion  is  also  present  in  the  products,  and 
is  therefore  not  taken  into  account.  If  the  volume  of  the  products  (at  0°  C)  is  less 
than  the  volume  of  the  mixture  of  gas  and  oxygen,  work  is  done  by  the  pressure  of 
the  atmosphere  when  the  gas  is  burnt  at  constant  pressure,  and  the  heat  of  com- 
bustion at  constant  pressure  is  greater  than  the  heat  of  combustion  at  constant 
volume  by  541  X  (ni  —  712)  calories. 


208 


GAS   PRODUCERS 
CALORIFIC  POWER  OF  GASES  (BURNT  AT  CONSTANT  VOLUME) 


Gas. 

Calorific  Power. 

Calories  per  Kilo. 

B.T.U.  per  Pound. 

Calories  per  Cubic 
Meter. 

B.T.U.  per  Cubic 
Foot. 

Higher 
Value. 

Lower 
Value. 

Higher 
Value. 

Lower 
Value. 

Higher 
Value. 

Lower 
Value. 

Higher 
Value. 

Lower 
Value. 

Carbon  monoxide  

2,426 

4,367 
21,858 
61,371 
23,897 

3  033 

340.9 
1707.0 
343.0 
1067.0 

1597.0 

288.2 
958.0 

Ethylene  

12,143 
34,095 
13,276 

11,365 
28,645 
11,913 

20,457 
51,561 
21,444 

15,191 
3,052 
9,492 

14,218 
2,565 

8,518 

Hydrogen  

Methane  

Carbon  

81,375 

146,475 

In  calculating  the  lower  value  of  the  calorific  power,  the  change  of  volume 
during  combustion  is  the  same  as  for  higher  value;  the  products  of  combustion  are 
cooled  to  0°  C.,  so  that  at  constant  volume  the  steam  is  actually  condensed,  but  the 
lower  value  of  the  calorific  power  is  found  by  deducting  the  latent  heat  of  the  steam 
from  the  higher  value,  whether  the  gas  is  burnt  at  constant  volume  or  at  constant 
pressure. 

Or  it  may  be  calculated  from  the  gross  calorific  power  at  constant  pressure, 
found  as  above,  and  the  change  in  volume  during  combustion  as  follows: 


Constituent. 

Molecular  Volumes  in 
22.32  c.m.  of  the  Gas. 

Molecular  Volumes  of 
Oxygen  Required  for 
Combustion. 

Volume,  after 
Combustion 
(Molecular  Volume). 

Hydrogen.  .  .  .-  

0    162 

0   081 

Carbon  monoxide  

0   210 

0  105 

0  210 

Methane                   

0  013 

0  026 

0  013 

Carbon  dioxide  

0.085 

0  085 

Oxygen  

0.002 

0  002 

Nitrogen  

0.528 

0  528 

Total  

1.000 

0.212 

0  838 

MEAN  MOLECULAR  HEATS  OF  GASES  AT  CONSTANT  PRESSURE  BETWEEN  THE 
ABSOLUTE  ZERO  AND  THE  TEMPERATURE  t°  C. 

Mean  Molecular  Heat  *  (Centigrade  Units). 


6.5  +  0.0006  X(«  +  273) 


Gas. 

Carbon  monoxide 
Hydrogen 
Methane 
Nitrogen 
Oxygen 

Carbon  dioxide 6.5  +  0.0037  X  (t  +  273) 

Water  vapor 6.5  +  0.0029  X  (J  +  273) 


*  Le  Chatelier,  "Cours  de  Chimie  Industrielle." 


PHYSICAL    PROPERTIES   OF   GASES 
DATA  ON  COMBUSTION 


209 


Combustibles, 
One  Pound  of 

Cu.  Ft. 
at 
62'  F. 

Burning  to 

Oxygen 
Required. 

Cu.  Ft. 
O. 
per 
Cu.  Ft, 
Comb. 

Air 
Required. 

Cu.  Ft. 
Air 

per 

Cu.  Ft. 
Comb. 

Heat  Developed 
(B.T.U.) 

Pounds. 

Cu.  Ft. 
at 
62°  F. 

Pounds. 

Cu.  Ft. 
at 
62°  F. 

Per 
Pound 
Comb. 

Per 

Cu.  Ft, 
Comb, 
at 
62°  F. 

Carbon 

CO2 
CO 

CO2 
Water  vapor 
H2O 
CO2  and 
water  vapor 

2.66 
1.33 
0.57 
8.00 

4.00 
3.43 

31.6 
15.8 
6.8 
95.0 

47.5 
40.7 

11.6 
5.8 
2.5 
34.8 

17.4 
14.9 

152 
76 
32.5 
456 

228 
195 

14,500 
4,450 
4,385 
62,000 

23,976 
21,476 

324 
326 

1010 
1590 

Carbon  

0.5 
0.5 

2.0 
3.0 

Carbon  monoxide.  .  .  . 
Hydrogen     

13.55 
190.00 

23.75 
13.55 

2.4 

2.4 

9.6 
14.4 

Marsh  gas,  CH4.  .  . 

Olefiant  gas,  C2H4  .  .  . 

WEIGHT  AND  VOLUME  OF  GASES  AND  AIR  REQUIRED  IN  COMBUSTION 


Name. 

Weight  per 
Cubic  Foot  in 
Pounds  at 
32°  F.  and  14.7 
Pounds  per 
Square  Inch. 

Volume  in  Cubic  Feet 
of  1  Pound  of  Gas  at 
14.7  Pounds  per 
Square  Inch. 

Cubic  Feet 
Required  to 
Burn  1  Cubic 
Foot  of  Gas. 

Pounds 
Required  to 
Burn  1  Pound 
of  the  Gas. 

Cubic  Feet 
Formed  of 

32°  F. 

62°  F. 

Oxygen 

Air. 

Oxygen 

Air. 

Steam. 

CO2. 

Air   .                   

0.08073 
0.12300 
0.07830 
0.00599 
0.04470 
0.07830 
0.07830 
0.08940 

12.39 
8.12 
12.77 
178.80 
22.37 
12.77 
12.77 
11.20 

13.12 
8.60 
13.55 
189.80 
23.73 
13.55 
13.55 
11.88 

0.5 
0.5 
2.0 

3.0 

2.39 
2.39 
9.60 

14.4 

0.57 

8.00 
4.00 

3.43 

2.4 
34.8 
17.4 

14.9 

0 

1 

2 
2 

1 
0 
1 

2 

Carbon  dioxide  

Carbon  monoxide  

Hydrogen  

Marsh  gas  

Nitrogen  

Olefiant  gas  

Oxygen.  .  . 

HEATING  VALUE  OF  GASES 


Gas. 

B.T.U.'s  per  Cu.Ft. 

Acetylene  

1556 

Alcohol,  amyl  

1684 

Alcohol,  ethyl  

1684 

Alcohol,  methyl  

1135 

Aldehyde  

1612 

Benzene  

3818 

Blast-furnace  gas  .  .  . 

90 

Butane  

3415 

Butylene  

3300 

Carbon  vapor  to  CO  . 

282 

Carbon  vapor  to  CO2 

1342 

Carbon  monoxide  .  .  . 

337 

Carbureted  water  gas 

575 

Coal  gas  

680 

Gas.  B.T.U.'s  per  Cu.Ft. 

Coke-oven  gas 600 

Ethane 1860 

Ether 3264 

Ethylene 1670 

Hydrogen 344 

Methane 1049 

Natural  gas,  average 1000 

Oil  gas 845 

Producer  gas,  coke 125 

Producer  gas,  hard  coal  ....  145 

Producer  gas,  soft  coal 145 

Propane 2627 

Propylene 2500 

Water  gas 300 


210 


GAS   PRODUCERS 


Specific  Heat. — This  term  denotes  the  amount  of  heat,  expressed  in  heat  units, 
which  is  required  to  raise  by  1°  the  temperature  of  unit  weight  of  a  substance. 
Since  a  heat  unit  is  the  amount  of  heat  required  to  raise  by  1°  the  temperature  of 
unit  weight  of  water,  the  specific  heat  of  a  substance  is  the  ratio  between  the  amount 
of  heat  needed  to  raise  by  1°  the  temperature  of  unit  weight  of  the  substance  and 
the  amount  of  heat  required  to  raise  by  1°  the  temperature  of  unit  weight  of  water. 
If  the  unit  of  weight  is  the  pound  avoirdupois,  and  the  temperature  is  measured  in 
Fahrenheit  degrees,  the  specific  heat  is  expressed  in  British  thermal  units,  while  if 
the  unit  of  weight  is  the  kilogram,  and  the  temperature  is  measured  in  Centigrade 
degrees,  the  specific  heat  is  expressed  in  calories.  It  is  expressed  by  the  same 
number  in  each  case. 

The  amount  of  heat  required  to  raise  by  1°  the  temperature  of  a  body  which  is 
free  to  expand,  or,  as  it  is  said,  is  kept  under  constant  pressure,  is  not  the  same  as 
the  amount  required  to  produce  the  same  change  in  temperature  in  the  body  if  it 
is  kept  at  a  constant  volume.  For  every  substance  there  are,  therefore,  two  values 
for  the  specific  heat,  one  for  constant  pressure  and  one  for  constant  volume.  There 
is  also  what  is  termed  specific  heat  by  volume,  which  is  the  amount  of  heat,  expressed 
in  heat  units,  required  to  raise  by  1°  the  temperature  of  unit  volume  of  a  substance. 
But  when  the  term  "  specific  heat  "  is  used  without  any  qualification,  as  in  the 
statement  "  the  specific  heat  of  nitrogen  is  0.244,"  it  refers  to  specific  heat  by  weight 
and  at  constant  pressure. 


CALCULATING  MEAN  SPECIFIC  HEAT  IN  A  GAS 


Constituent. 

Per  Cent  by 
Volume. 

Weight  of 
1  Cubit  Foot, 
in  Pounds. 

Weight  of 
Constituent 
in  Pounds. 

Specific  Heats. 

Sp.  HX 
Wt.XVol. 

Authority 
for  Value  of 
Sp.  H. 

Benzol.           

1.00 

0.20640 

0.20640 

1  .187 

0.2450 

Wullner 

C,H, 

3.75 

0.07410 

0.27787 

1.245 

0.3460 

1  1 

CO                       

8.04 

0.7407 

0.59552 

1.403 

0.8355 

>' 

H                           

47.04 

0.00530 

0.24931 

1.396 

0.3580 

Regnault 

CH4.           

36.02 

0.04234 

1.52508 

1.319 

2.0115 

Masson 

CO2  

1.60 

0.11637 

0.18619 

1.300 

0  .  2420 

<  < 

o            

0.39 

0.08463 

0.03300 

1.405 

0.0464 

Regnault 

N                   

2.15 

0.07429 

0  .  16046 

1.405 

0.2255 

«  ( 

100  00 

3  22383 

4.3099 

4.3099 
3.22383 


=  1.337,  the  value  of  the  mean  specific  heat  for  the  above  gas. 


PHYSICAL   PROPERTIES    OF    GASES 


211 


TABLE  OF  MEAN  SPECIFIC  HEATS  AT  CONSTANT  PRESSURE 
(In  B.T.U.  per  Pound) 


Degrees,  F.                    Carbon  Dioxide. 

Water  Vapor.                          Nitrogen. 

Oxygen. 

212                            0.201 

0.446 

0  .  244 

0.214 

392                         0.210 

0.462 

0.249 

0.218 

572                          0.219 

0.478 

0.253 

0.222 

752                          0.227 

0.494 

0.257 

0.225 

932 

0.236 

0.510 

0.262 

0.229 

1112 

0.245 

0.526 

0.266 

0.233 

1292 

0  .  254 

0.541 

0.270 

0.237 

1472 

0.263 

0.557 

0.275 

0.241 

1652 

0.271 

0.573 

0.279 

0.244 

1832 

0.280 

0.589 

0.284 

0.248 

2012 

0.289 

0.605 

0.288 

0.252 

2192 

0.298 

0.621 

0.292 

0.256 

2372 

0.307 

0.637 

0.297 

0.260 

2552 

0.315 

0.652 

0.301 

0.264 

2732 

0.324 

0.668 

0.305 

0.267 

2912 

0.333 

0.684 

0.310 

0.271 

3092 

0.342 

0.700 

0.314 

0.275 

3272 

0.351 

0.716 

0.318 

0.279 

3452 

0.360 

0.732 

0.323 

0.282 

3632 

0.368 

0.748 

0.327 

0.286 

3812 

0.377 

0.764 

0.331 

0.290 

3992 

0.385 

0.780 

0.336 

0.294 

4172 

0.394 

0.796 

0.340 

0.298 

4352 

0.403 

0.812 

0.344 

0.301 

4532 

0.412 

0.828 

0.349 

0.305 

Inaccuracies  in  the  experimental  data  on  which  this  table  is  based  render  it 
useless  to  attempt  to  interpolate  more  closely  than  to  90°. 

Inasmuch  as  the  specific  heat  of  a  gas  is  dependent  upon  its  density  and  tem- 
perature, it  is  better  called  its  "  coefficient  of  heat  absorption." 

TABLE  OF  SPECIFIC  HEAT  OF  GASES  (SIEBEL) 

At  Constant  At  Constant 

For  equal  weights,  water  »*1.  T,  -,r  • 

Pressure.  Volume. 

Air  0.02377  0. 1688 

Carbonic  acid  (CO2) 0. 2164  0. 1714 

Carbonic  oxide  (CO) 0.2479  0. 1768 

Hydrogen 3.4046  2.4096 

Light  carbureted  hydrogen 0.5929  0.4683 

Nitrogen 0. 2440  0. 1740 

Oxygen 0.2182  0.1559 

Steam,  saturated 0.3050 

Steam,  gas 0.4750  0.3700 

Sulphurous  acid 0. 1553  0. 1246 

Other  authorities  give  the  following  values: 


212 


GAS   PRODUCERS 


SPECIFIC  HEATS  AT  CONSTANT  PRESSURE 

Air 0.2375 

Oxygen 0.2175 

Hydrogen 3.4090. 

Nitrogen 0.2438' 

Carbon  dioxide,  CO2 0.2170 

Carbon  monoxide,  CO 0 . 2479 

Olefiant  gas  (ethylene),  C2H4 0.4040 

Marsh  gas  (methane),  CH4 0. 5929 

Blast-furnace  gas 0.2280 

Chimney  gases  from  boilers 0 . 2400 

Steam,  superheated 0.4805 

VOLUMETRIC  SPECIFIC  HEATS 

Air,  oxygen,  carbon  monoxide,  hydrogen,  and  nitrogen  =  0.019. 
Carbon  dioxide  and  marsh  gas  =  0.027. 
Producer  gas  =  0.019. 

Volumetric  specific  heat  is  the  quantity  of  heat  required  to  raise  the  tempera- 
ture of  1  cu.ft.  1°  from  32°  to  33°  F. 


SPECIFIC  HEAT  OF  GASES  AND  VAPORS 


Specific  Heat  of 
Equal  Weights. 


Specific  Heat  of 
Equal  Volumes. 


Specific  Heat  of 
Constant  Volumes. 


Air 0.2374 

Oxygen 0.2175 

Simple  Nitrogen 0 .2438 

Gases  Hydrogen  3 .4090 

Chlorine.  . 0.1210 

Bromine 0 .0555 

Binoxide  of  nitrogen : 0.2315 

Carbonic  oxide 0.2450 

Carbonic  acid 0.2163 

Sulphureted  hydrogen 0 .2432 

Sulphurous  anhydride 0 . 1553 

Hydrochloric  acid 0.1845 

Nitrous  oxide 0.2262 

Nitric  oxide 0 .2317 

Ammonia 0 . 5083 

Marsh  gas 0 . 5929 

Olefiant  gas  (ethylene) 0 .4040 

Water  (steam) 0 .4805 

Ether 0.4810 

Chloroform 0 . 1567 

Alcohol 0.4534 

Turpentine 0.5061 

Bisulphide  of  carbon 0 . 1570 

Benzole 0.3754 

Acetone..  0.4125 


0.2374 
0.2405 
0.2370 
0.2359 
0.2962 
0.3040 


0 . 1687 
0.1559 
0 . 1740 
2.4096 


0.2406 
0.2370 
0.3307 
0.2857 
0.3414 
0.2333 
0.3447 
0.2406 
0.2966 
0.3277 
0.4106 


0 . 1768 
0.1714 

0.1246 


0.4683 


0.2984 
1.2296 
0.6461 
0.7171 
2.3776 
0.4140 
1.0114 
0.8244 


0.3337 
0.3411 

0.3200 


PHYSICAL   PROPERTIES    OF    GASES 


213 


SPECIFIC  HEAT  OF  WATER  AT  VARIOUS  TEMPERATURES— (SIEBEL) 


Temp.  Deg.  F. 

Specific  Heat. 

Heat  to  Raise 
One  Pound  of  Water 
from  32°  to  Given 
Temperature. 

Temp.  Deg.  F. 

Specific  Heat. 

Heat  to  Raise 
One  Pound  of  Water 
from  32°  to  Given 
Temperature. 

32 

1.0000 

0.000 

248 

1.0177 

217.449 

50 

1  .0005 

18.004 

244 

1.0202 

235.791 

68 

1.0012 

36.018 

284 

1.0232 

254  .  187 

86 

1.0020 

54.047 

302 

1.0262 

272.628 

104 

1.0030 

72.090 

320 

1.0294 

291.132 

122 

1.0042 

90.157 

338 

1.0328 

309.690 

140 

1.0056 

108.247 

356 

1  .0364 

328.320 

158 

1.0072 

126.378 

374 

1  .0401 

347.004 

176 

1.0089 

144.508 

392 

1.0440 

365.760 

194 

1  .0109 

162.686 

410 

1.0481 

384  .  588 

212 

1.0130 

180.900 

428 

1.0524 

403.488 

230 

1.0153 

199.152 

446 

1.0568 

422.478 

SPECIFIC 

HEATS 

SOLIDS 

Alumina  

0.1970 

Magnesia  

0.2220 

Aluminum  

2185 

Limestone,  magnesian  .  .  . 

.2170 

Antimony  

0508 

Marble  

.2100 

Bismuth,  melted  .  . 

0308 

Mercury  

.0333 

Brass  

939 

Nickel  

.1086 

Cadmium  

0567 

Oak  

.5700 

Chalk  

2150 

Pear  woods  

.5000 

Charcoal  

2410 

Phosphorus  

.1887 

Clay,  burnt  

1850 

Pine  (turpentine)  

.4670 

Coal  

...0.  20-.  2400 

Platinum  

.0324 

Coke  

2030 

Quartz  

.1880 

Copper  

0951 

Quicklime  

.2170 

Corundum  

1980 

Sand  (river)  

.1950 

Fir  

6500 

Silica  

.1910 

Gold  

0324 

Soda  

.2310 

Glass  

1937 

Silver  

.0570 

Graphite  

2020 

Steel,  hard  

.1175 

Gypsum  

1970 

Steel,  soft  

.1165 

Ice  

5040 

Sulphur  

.2026 

Iron,  cast  

1298 

Sulphur,  melted  

.2340 

Iron,  wrought  .... 

1138 

Tin  

.0562 

Lead  

0314 

Tin,  melted  

.0637 

Lead,  melted  

0402 

Zinc  

.0956 

214 


GAS   PRODUCERS 


Weights  and  Volumes. — The  molecular  weights,  when  substituted  for  the 
symbols  in  a  chemical  equation,  also  form  an  equation  and  the  quantities  represent 
relative  weights  of  the  members  of  the  equation.  Thus, 


12  +  18  =  28  +  2. 

Here  the  carbon  may  be  any  unit  of  weight,  pounds,  kilograms,  etc.  Then 
12  Ibs.  of  carbon  would  release  2  Ibs.  of  hydrogen  by  this  reaction.  Also  the  mole- 
cules of  all  true  gases  occupy  equal  volumes.  The  conversion  from  weight  to  volume 
may  be  obtained  in  the  calculation  of  gases  as  follows:  The  weight  of  1  cu.m.  of 
hydrogen  is  O.C9  kg.;  its  molecular  weight  is  2;  then  24-0.09  =  22.22  is  its  molecular 
volume,  which  is  the  same  for  all  true  gases.  Assuming  the  molecular  weight  of 
the  gas  to  be  represented  by  kilograms,  then  each  molecule  of  the  gas  may  be 
assumed  to  be  22.22  cu.m.  The  weight  of  one  molecule  (O2)  of  oxygen  thus  occupies 
22.22  cu.m.;  its  molecular  weight  is  32  and  its  weight  would  therefore  be 

32 -=-22.22  =  1.44  kg.  per  cu.m. 

Professor  Richards  points  out  that  the  molecular  weight  may  also  be  taken  as 
avoirdupois  ounces  wrhen  the  result  will  be  obtained  in  cubic  feet.  Let  02  =  22.22  cu.ft. 
and  the  molecular  weight  of  oxygen  be  again  32,  or  32  oz.  Then  32 -f- 22.22  =  1.44  oz. 
per  cu.ft. 

As  Professor  Richards  mentions,  the  ratio  of  the  ounce  to  the  kilogram,  1:35.26, 
is  nearly  identical  with  that  of  the  cubic  foot  to  the  cubic  meter,  1:35.31,  the 
difference  being  but  0.0-|th%. 

Again,  dividing  the  molecular  weight  of  any  gas  by  the  factor  22.22  gives  as  a 
result  its  actual  weight  in  kilograms.  Where  the  molecular  weight  is  expressed  in 
pounds  the  gas  occupies  357.5  cu.ft. 

As  an  axiom  it  must  be  remembered  that  equal  volumes  of  gases  contain  equal 
numbers  of  molecules  (pressure  and  temperature  being  equal);  this  is  known  as 
Avogradro's  law. 

MOLECULAR  WEIGHT 


Name. 

Symbol. 

Molecular 
Weight. 

Name. 

Symbol. 

Molecular 
Weight. 

Hydrogen  

H, 

2.00 

Allylene  

C3H4 

39.91 

Oxygen  

o. 

31.92 

Benzene  

77.83 

Nitrogen  

N, 

28.02 

Toluene  

C7H8 

91.80 

Carbon  monoxide 

CO 

27  93 

Naphthalene 

127  72 

Carbonic  acid  

CO, 

43.89 

Diphenyl  

('    H 

153.65 

Methane  (marsh  gas) 

15  97 

Anthracene 

(  '    FT 

177  59 

Ethane  

29.94 

Pyrene  

C    Tl 

201.54 

Propane.  ...          

43.91 

Chrysene  

C    H 

'227.48 

Butane.  .        

57.89 

Ammonia  

NH3 

17.01 

Pentane  

C5Hl2 

71.86 

Sulphureted  hydrogen  .  .  . 

H2S 

33.98 

Hexane  ...              

85.83 

Carbon  disulphide  

CS2 

75.95 

Ethylene  (olefiant  gas)  .  . 

C,H4 

27.94 

Nitrous  oxide  

N,O 

43.98 

Propylene 

C3H« 

41.91 

Nitric  oxide  

NO 

29.97 

Butylene 

C4H8 

55.89 

Cyanogen.          

C2N2 

51.96 

69.86 

Water  vapor  

H,O 

17.96 

Acetylene  (ethine) 

25  94 

Chlorine  

Cl, 

70.74 

PHYSICAL   PROPERTIES   OF   GASES 
ATOMIC  WEIGHT  OF  SOME  ELEMENTS 


215 


Name. 

Symbol. 

Atomic 
Weight. 

Name. 

Symbol. 

Atomic 
Weight. 

Aluminum 

Al 

27.02 

Lithium  

Li 

7.01 

\ntimony 

Sb 

120.0 

Magnesium  

Mg 

24.0 

\rsenic 

\s 

74.9 

Manganese  

Mn 

55.0 

Barium 

Ba 

136.8 

Mercury  

Hg 

199.8 

Bi 

208  0 

Nickel  

Ni 

58.6 

B 

11  0 

Nitrogen  

N 

14.01 

Br 

79  75 

Oxygen  

o 

15.96 

Cadmium 

Cd 

111  7 

Palladium  

Pd 

106.3 

Ca 

39  91 

Phosphorus  

P 

30  .  96 

Carbon 

c 

11.97 

Platinum  

Pt 

194.3 

Cerium 

Ce 

139.9 

Potassium  

K 

39.04 

Cl 

35  37 

Rhodium  

Rh 

102.7 

Cr 

52  45 

Silicon  

Si 

28.3 

Cobalt 

Co 

58.8 

Silver  

Ag 

107.66 

Copper 

Cu 

63.2 

Sodium  

Na 

22.995 

Fluorine 

F 

19.0 

Strontium  

Sr 

87.3 

Gold 

Au 

196.7 

Sulphur  

Q 

31.98 

Hydrogen 

H 

1.0 

Thorium  

Th 

232.0 

Iodine 

I 

126.53 

Tin  

Sn 

118.8 

Iridium                      * 

Ir 

192.5 

Titanium  

Ti 

47.9 

Iron 

Fe 

55.9 

LTranium  

U 

239.0 

Lead 

Pb 

206.4 

Zinc  

Zn 

65.3 

CUBIC  FEET  OF   GASES  TO   THE   POUND 


Acetylene 13 . 750 

Air 12.333 

Alcohol,  grain,  vapor  ....  7.775 

Alcohol,  wood,  vapor  ....  11. 203 

Aldehyde,  vapor 8 . 085 

Ammonia 21.000 

Benzene,  vapor 4.808 

Blast-furnace  gas 12.650 

Butane 6.245 

Butylene 6.414 

Carbon,  vapor  .  . 14.930 

Carbon  dioxide 8. 147 

Carbon  disulphide,  vapor.  4.706 

Carbon  monoxide 12.804 

Coal  gas 31.600 

Cyanogen 6.880 


Ethane 11.950 

Ether,  vapor 4.860 

Ethylene, 12.580 

Ethylene  chloride,  vapor.      3.631 

Fusel  oil,  vapor 3 . 936 

Hydrogen 178.230 

Hydrogen  sulphide 10.370 

Methane 22.301 

Natural,  gas,  average  ....   22 . 500 

Nitrogen : 12.752 

Oxygen 11.209 

Producer  gas 13.333 

Propane 8.148 

Propylene 8.540 

Water  gas : 22.000 

Water,  vapor 19.912 


216 


GAS   PRODUCERS 


SPECIFIC  GRAVITY,  WEIGHT,  AND  SOLUBILITY  IN  WATER  OF  VARIOUS    GASES    AT 

60°  F.  AND  80  INCHES  BAROMETER 


Name. 

Specific 
Gravity, 
Air  Equal 
1.000. 

Weight  of  a 
Cubic  Foot  in 
Pounds, 
Avoirdupois. 

Weight  of  a 
Cubic  Foot  in 
Grains. 

Number  of 
Cubic  Feet 
Equal  to 
1  Pound. 

Solubility 
100  Vols.  of 
Water 
Absorbed. 

Hydrogen  

0.0691 

0.00529997 

37  09 

188  68 

1  93  vols 

Light  carburetted  hydrogen.  ..  . 

0.5559 

0  0428753 

300  12 

23  32 

3  91    " 

Ammonia  

0.590 

0  045253 

316.77 

22  09 

72  720    '  ' 

Carbonic  oxide  

0.967 

0  0741689 

519.18 

13  48 

2  43    " 

Olefiant  gas  

0.968 

0  0742456 

519.71 

13  46 

16  15    " 

Nitrogen  

0.9713 

0  07449871 

521  49 

13  42 

1  48    " 

Air  

1  000 

0  0767 

536  90 

13  03 

1  70    " 

Nitric  oxide  

1  039 

0  0796913 

557  83 

12  54 

Not  soluble 

Oxygen  

1  1056 

0  08479952 

593  59 

11  79 

2  99  vols 

Sulphuretted  hydrogen  

1  1747 

0  09009949 

630  69 

11  09 

323  26    " 

Nitrous  oxide.  . 

1  527 

0  1171209 

819  84 

8  53 

77  78    " 

Carbonic  acid. 

1  529 

0  1172743 

820  92 

8  52 

100  20    " 

Sulphurous  acid 

2  247 

0  1723449 

1206  41 

5  80 

4276  60    " 

Chlorine  

2.470 

0.189449 

1326.14 

5.27 

236  80    " 

Bisulphide  of  carbon  

2.640 

0  202488 

1417.41 

4.93 

Not  soluble 

WEIGHTS  OF  GASES 


Gas. 

Formula. 

Molecular  Weight. 

Density  Referred 
to  Hydrogen. 

Weight  of 
Cubic  Meter. 

Hydrogen  .    . 

H, 

2 

1 

0  09  kilos 

Water  vapor  

H2O 

18 

9 

0  81      " 

Nitrogen  .    .    . 

N, 

28 

14 

1  26      " 

Oxygen  

o. 

32 

16 

1  44      " 

Carbon  monoxide.  . 

CO 

28 

14 

1  26      " 

Carbon  dioxide  .  . 

CO2 

44 

22 

1  98      " 

Marsh  gas  

CH4 

16 

8 

0  72     " 

Etc. 

CHAPTER   VIII 
CHEMICAL    PROPERTIES    OF    GASES 

THE  gases  present  in  producer  gas  may  be  classed  as  follows,  according  to 
Sexton : 

1.  COMBUSTIBLE  GASES. 

Hydrogen H 

Carbon  monoxide CO 

Marsh  gas,  methane CH* 

Ethylene CoHj 

Acetylene C2H2 

2.  DILUENTS. 

Nitrogen X 

Carbon  dioxide CO2 

Oxygen 0 

In  addition  there  may  be  present  combustible  and  non-combustible  vapors, 
such  as  tarry  matters  and  some  other  substances  which  may  have  considerable 
influence  on  the  quality  of  the  gas,  but  which  are  not  given  in  the  ordinary  analysis 
of  the  gas,  because  they  are  condensed,  and  thus  removed  in  the  preparation  of  the 
sample  for  analysis. 

COMBUSTIBLE   GASES 

Hydrogen  (H). — Atomic  weight  1;  molecular  weight,  2.  This  gas  is  always 
present  in  larger  or  smaller  quantity.  It  is  found  in  considerable  quantity  in  the 
products  of  the  destructive  distillation  of  coal,  and  is  therefore  present  in  coal  gas. 
It  is  also  liberated  whenever  steam  comes  in  contact  with  very  hot  carbon,  carbon 
monoxide,  or  carbon  dioxide  being  formed  at  the  same  time,  according  to  the  tem- 
perature and  the  quantity  of  carbon  present,  thus 

C+   H2O=CO  +  2H, (1) 

C+2H20=CO2  +  4H (2) 

Hydrogen  is  colorless  and  odorless  and  very  light;  indeed,  it  is  the  lightest 
known  substance.  It  is  less  than  ^  as  heavy  as  air;  its  specific  gravity  (air=l) 
being  0.06926  and  1  cu.ft.  weighs  at  0°  C.  and  760  mm.  barometer,  0.0056  Ibs.,  or 
1  II).  occupies  178.57  cu.ft.  Its  specific  heat  is  2.414.  It  is  very  readily  com- 

217 


218  GAS   PRODUCERS 

bustible,  and  burns  with  a  pale  blue,  almost  non-luminous,  flame.  One  pound 
evolves  on  combustion  34,180  calories  or  61,524  B.T.U.  of  heat.  It  is  therefore  one 
of  the  most  valuable  constituents  of  fuel  gas,  but  owing  to  its  extreme  lightness,  if 
present  in  large  proportion,  it  makes  the  gas  light  and  bulky.  One  cubic  foot  evolves 
only  one  191.4  calories  or  344.5  B.T.U.  on  combustion.  When  it  burns  water  is 
formed, 

H20  ...........     (3) 


It  requires  eight  times  its  own  weight  or  half  its  own  volume  of  oxygen  for 
combustion,  and  yields  nine  times  its  own  weight  of  water,  which,  if  the  temperature 
be  above  100°  C.,  will  occupy  the  same  volume  as  the  hydrogen  would  do  under 
the  same  conditions  of  temperature  and  pressure.  It  requires  about  2.4  times  its 
own  volume  or  34.78  times  its  own  weight  of  air  for  complete  combustion.  The 
influence  of  hydrogen  in  a  gas  is  to  make  it  light  and  bulky,  to  add  largely  to  its 
heating  power,  and,  at  the  same  time,  to  increase  very  much  the  amount  of  air 
required  for  combustion,  and,  since  the  specific  heat  of  steam  is  very  high,  also  to 
increase  the  amount  of  heat  carried  away  in  the  products  of  combustion. 

Carbon  Monoxide  (CO).  —  Molecular  weight,  27.93,  or  practically  28.  This  is 
one  of  the  most  important  constituents  of  fuel  gas.  It  is  colorless  and  odorless,  and 
burns  with  a  characteristic  pale  blue,  feebly  luminous  flame,  forming  carbon  dioxide 
thus: 

=C02  .............     (4) 


One  pound  evolves  on  combustion  2430  calories  or  4374  B.T.U.  It  requires  for 
complete  combustion  0.57  times  its  own  weight  and  half  its  owrn  volume  of  oxygen, 
and  yields  1.57  times  its  own  weight  of  carbon  dioxide.  The  amount  of  air  required 
is  about  2.4  times  its  own  volume  or  2.48  times  its  own  weight. 

It  is  among  the  products  of  the  destructive  distillation  of  coal,  and  is  produced 
by  the  action  of  hot  carbon  on  carbon  dioxide,  thus 

C02  +  C  =  2CO,      ...........     (5) 

and  of  steam  on  hot  carbon  (equation  (1)). 

As  the  specific  heat  of  carbon  dioxide  is  only  0.2479,  the  amount  of  heat  carried 
away  by  the  products  of  combustion  is  not  large.  Its  specific  gravity  (H  =  l)  is  14; 
and  (air=l)  is  0.9671  and  one  cubic  foot  weighs  0.0781  Ib. 

Marsh  Gas,  Methane  (CH^).  —  Molecular  weight,  15.97  (practically  16).  —  This 
is  a  colorless  and  odorless  gas  which  occurs  in  large  quantity  in  natural  gas.  It  is 
produced  by  the  decompositions  by  which  vegetable  matter  passes  into  coal,  and 
is  therefore  often  present  in  coal  mines,  where  it  is  known  as  fire-damp.  It  is 
among  the  products  of  the  destructive  distillation  of  coal,  and  is  therefore  always 
present  in  coal  gas,  through  rarely  in  large  quantity.  Its  specific  gravity  (air  =  l) 
is  0.5530,  whence  it  is  often  called  light  carbureted  hydrogen.  One  cubic  foot 
weighs  0.0447  Ib.  It  burns  readily  writh  a  slightly  luminous  flame,  forming  carbon 
dioxide  and  wrater  thus: 

CH4+40=C02  +  2H20.  .......     (6) 


CHEMICAL   PROPERTIES   OF   GASES  219 

If  the  quanity  of  oxygen  be  insufficient  for  complete  combustion  it  yields  carbon 
monoxide,  hydrogen,  and  lower  hydrocarbons  with  but  little  free  carbon,  so  that 
little  or  no  smoke  is  produced.  It  requires  for  complete  combustion  four  times  its 
own  weight  and  twice  its  own  volume  of  oxygen,  or  17.3  times  its  weight  and  9.52 
times  its  own  volume  of  air.  It  yields  2.25  times  its  own  weight  of  water  and  2.75 
times  its  own  weight  of  carbon  dioxide.  Its  calorific  power  is  13,062  calories  or 
23,512  B.T.U. 

Ethylene  (C2H4).  —  Molecular  weight,  27.94  (28).  This  gas  is  present  in  con- 
siderable quantity  in  gases,  such  as  coal  gas  produced  by  destructive  distillation. 
It  is  colorless  and  odorless,  burns  very  easily,  with  a  very  luminous  flame,  which 
becomes  readily  smoky.  It  is  the  chief  illuminating  constituent  of  coal,  and  similar 
gases.  On  complete  combustion  it  yields  water  and  carbon  dioxide, 


C2H4f6O  =  2C02  +  2H2O  .........     (7) 

It  requires  for  complete  combustion  3.42  times  its  own  weight  and  three  times 
its  own  volume  of  oxygen,  or  14.87  times  its  own  weight,  and  14.28  times  its  own 
volume  of  air.  It  yields  twice  its  own  volume  of  carbon  dioxide  and  twice  its  own 
volume  of  steam.  With  an  insufficient  supply  of  air  it  burns  with  a  very  smoky 
flame.  Its  specific  gravity  (air  =  l)-is  0.9784,  and  a  cubic  foot  weighs  0.0784  Ibs. 
Its  specific  heat  is  0.4040.  It  yields  on  complete  combustion  11,143  C.U.  or  20,057 
B.T.U.  of  heat. 

Acetylene  (C2H2).  —  This  is  a  colorless  gas,  having  a  most  unpleasant  odor.  It 
burns  readily  with  a  very  brilliant  flame,  and  shows  a  great  tendency  to  produce 
smoke  by  the  separation  of  carbon: 


..........     (8) 

It  requires  three  times  its  own  weight  and  2.5  times  its  own  volume  of  oxygen 
for  complete  combustion.     Its  specific  gravity  (air=l)  is  0.91,  and  a  cubic  foot  weighs 
0.0731  Ibs.     It   is   an   unstable   body,   decomposing  very   readily  with   evolution   ot 
heat,  and  is  of  little  importance  as  a  fuel  gas. 

Natural    Gas.  —  Sexton  says    that   natural  gas  is    composed   almost   entirely   of 
combustible  gases,  there  being  only  4.4%  of  diluents,  as  compared  with  95.6%  of 
combustible  gases  and  its  calorific  power  will  therefore  be  very  high.     Owing  to  the 
large  quantity  of  methane,  it  burns  with  a  non-luminous  flame.     The  percentage  com- 
position is  about: 

Volume,  Weight,  Weight  of  Weight, 

Per  Cent.  Cu.Ft,  Gas,  Lbs.  Per  Cent. 

Carbon  dioxide.  .      0.6     X     0.1227     =     0.0736  1.82 

Carbon  monoxide     0.6     X     0.0781      =     0.0469  1.16 

Oxygen  .........     0.8     X     0.0893     =     0.0714  1.77 

Ethylene  ........      1.0     X     0.0784     =     0.0784  1.94 

Ethane  .........     5.0     X     0.0837     =     0.4185  10.35 

Methane  ........   67.0     X     0.0447     =     2.9949  74.09 

Hydrogen  .......   22.0     X     0.0056     =     0.1232  3.05 

Nitrogen  ........     3.0     X     0.0784     =     0.2352  5.82 

4.0421  100.00 


220  GAS   PRODUCERS 


DILUENT   GASES. 

Nitrogen  (N). — Atomic  weight  14;  molecular  weight  28.  This  is  a  colorless 
and  odorless  gas,  always  present  in  fuel  and  lighting  gases.  It  is  produced  in  small 
quantity  by  the  destructive  distillation  of  nitrogenous  organic  matter,  and  is  there- 
fore present  in  small  quantities  in  coal  and  similar  gases.  It  forms  a  large  percentage 
of  the  air,  and  is  therefore  always  present  in  large  quantity  in  gases  produced  by  incom- 
plete combustion.  Its  specific  gravity  (air  =  l)  is  0.9701,  and  one  cubic  foot  weighs 
0.0784  Ibs.  It  is  not  combustible,  and  has  no  influence  on  fuel  gas,  except  to  act 
as  a  diluent.  Its  specific  heat  is  0.2438. 

Carbon  Dioxide  (C02).  Molecular  weight  43.89  (practically  44).  This  is  a 
colorless,  odorless,  non-combustible  gas.  It  is  produced  in  small  quantity  by 
destructive  distillation,  and  is  therefore  present  in  small  quantity  in  coal  gas.  It  is 
often  present  in  producer  gas  in  considerable  quantity,  being  produced  by  the  com- 
bustion of  carbon.  Its  specific  gravity  (air  =  l)  is  1.5196;  one  cubic  foot  weighs 
0.1227  Ibs.,  and  its  specific  heat  is  0.2163.  In  presence  of  excess  of  carbon  at  high 
temperatures  it  is  reduced  to  carbon  monoxide,  thus: 


=  2CO. 


Oxygen  (0). — This  gas  is  never  present  in  fuel  gas  except  by  leakage  after  the 
gas  has  coded,  since  at  high  temperatures  it  would  at  once  combine  with  the  combus- 
tible constituents  of  the  gas. 

Steam  (H20). — Molecular  weight,  17.97  (practically  18).  Water  vapor  is  always 
present  in  fuel  gas,  being  produced  by  the  vaporization  of  the  moisture  in  the  fuel, 
and  it  is  always  among  the  products  of  destructive  distillation,  and  it  may  be  produced 
by  the  combustion  of  hydrogen  or  hydrocarbons  owing  to  the  leakage  of  air  into  the 
gas.  At  temperatures  above  100°  C.  the  whole  of  the  water  will  be  in  the  condition 
of  vapor,  and  will  behave  exactly  like  any  other  gas.  At  temperatures  below  100°  C. 
part  of  the  steam  will  condense,  but  a  certain  amount  of  water  vapor  will  always 
remain  in  the  gas,  the  amount  depending  on  the  temperature,  as  at  every  temperature 
water  can  exist  in  the  condition  of  gas  or  vapor  till  it  exerts  a  definite  pressure. 

The  specific  gravity  of  steam  or  water  vapor  at  0°  and  760  mm.  is  0.622  (air— 1), 
and  one  cubic  foot  weighs  0.0502  Ibs.  As  its  specific  heat  is  0.4805,  the  presence  of 
water  vapor  causes  a  large  amount  of  heat  to  be  carried  away  in  the  products  of 
combustion.  There  may  also  be  present  a  considerable  amount  of  condensed  water 
in  the  form  of  fine  globules  or  mist. 

Tarry  Matter. — These  are  mostly  dense  hydrocarbons  of  very  uncertain  com- 
position, which  condense  at  moderate  temperatures  to  tarry  and  oily  liquids.  They 
burn  with  a  luminous,  often  smoky  flame.  On  being  passed  over  red  hot  coke  or 
red  hot  brickwork  they  are  broken  up  into  carbon,  which  is  deposited,  and  permanent 
gases  such  as  largely  marsh  gas  and  hydrogen.  The  influence  of  tarry  matters  on 
the  quality  of  gas  is  discussed  elsewhere. 

The  Air. — In  practice,  fuels  are  always  burnt  in  air.  The  air  consists  of  a  mixture 
of  oxygen  and  nitrogen  with  small  quantities  of  other  substances,  some  inert  gases 
resembling  nitrogen — which  have  been  recently  discovered,  but  which,  since  they 
have  no  influence  on  combustion,  can  be  neglected — carbon  dioxide,  very  minute 


CHEMICAL   PROPERTIES    OF    GASES 


221 


quantities  of  ammonia,  acid  gases,  etc.,  and  a  considerable  quantity  of  water  vapor. 
For  all  practical  purposes,  dry  air  may  be  taken  as  containing: 

By  Weight.         By  Volume. 

Oxygen 23  21 

Nitrogen , 77  79 

The  average  analysis  of  atmospheric  air  as  made  by  Professor  Lewes,  is  as  follows: 

Oxygen 20.61 

Nitrogen 77 . 95 

Carbon  dioxide 0 . 04 

Water  vapor 1 . 40 

Nitric  acid trace 

Ammonia.  trace 


100.00 

Composition    of    Industrial   Gases. — The  following  are  the  general  characteristics 
of  some  of  the  most  used  gases: 

PROPERTIES  OF  COMMERCIAL  GASES  (WYER) 


B.T.U. 

O.  Re- 

in 1  Cu. 

B.T.U. 

quired 

Air  for 

Names. 

H. 

CH<. 

C2H4. 

N. 

CO. 

O. 

CO2. 

Ft.  Ex- 

per 

for 

Com- 

plosive 

Cu.  Ft. 

Com- 

bustion. 

Mixture 

bustion. 

Natural  gas  (Pittsburg).  .  . 

3  0 

92.0 

3.0 

2.0 

91.0 

978 

1  94 

9   73 

Oil  gas 

32  0 

48.0 

16.5 

3.0 

0.5 

93.0 

846 

1  61 

8  07 

Coal  or  bench  gas.      .    . 

46  0 

40.0 

5.0 

2.0 

6.0 

0.5 

0.5 

91.7 

646 

1  21 

6  05 

Coke-oven  gas.                .    . 

50.0 

36.0 

4.0 

2.0 

6.0 

0.5 

1.5 

91.0 

603 

1  12 

5  60 

Carbureted  water  gas  . 

40  0 

25.0 

8.5 

4.0 

19.0 

0.5 

3.0 

92  0 

575 

1  05 

5  25 

Water  gas  

48.0 

2.0 

5.5 

38.0 

0.5 

6.0 

88.0 

295 

0.47 

2  35 

Producer  gas  from  hard  coal 

20.0 

49.5 

25.0 

0.5 

5.0 

68  0 

144 

0  22 

1   12 

Producer  gas  from  soft  coal. 

10.0 

3.0 

0.5 

58.0 

23.0 

0.5 

5.0 

65.5 

144 

0.24 

1.20 

Producer  gas  from  coke  .  .  . 

10.0 

56.0 

29.0 

0.5 

4.5 

63.0 

125 

0  19 

0  98 

The  following  table  is  credited  to  J.  M.  Morehead. 

APPROXIMATE  COMPOSITION  OF  ORDINARY  GASES 


Gas. 

Carbon 
Dioxide. 

Illumi- 
nants. 

Oxygen. 

Carbon 
Mon- 
oxide. 

Hydro- 
gen. 

Meth- 
ane. 

Nitro- 
gen. 

B.T.U. 
per 
Cu.  Ft. 

Specific 
Gravity. 

Water-gas,  24  c.p.  .  . 

4.5 

13  0 

0  5 

29.0 

32.0 

16.0 

5  0 

720 

0   63 

Coal-gas,  16  c.p  

2.0 

5  5 

0  5 

11.5 

43.5 

35.0 

2.0 

610 

0  45 

Acetylene  (commercial).  .. 

96.0 

1.0 

4.0 

1600 

0  92 

Flue  gas  

16.0 

4.5 

0.5 

79.0 

1  06 

Pintsh  gas  

0.5 

23.5 

0.5 

1.0 

18.5 

52.5 

3.5 

1100 

0  73 

Engine  exhaust  

8.0 

17.0 

75.0 

1  04 

Producer-gas  

6  0 

22  0 

11.0 

3  0 

58  0 

150 

0  89 

Natural  gas  

2  0 

2  7 

0  1 

1  0 

88.1 

5.2 

900 

0  56 

Blue  water-gas  

3.0 

43.25 

50.0 

0  5 

3.25 

350 

0  42 

Air  

20  7 

79.3 

1  00 

The  above  figures  are  given  as  an  average  of  those  which  ordinarily  obtain  in 
the  best  practice.  Local  conditions  and  requirements  probably  will,  of  course,  vary 
these  figures  in  individual  instances. 


222 


GAS   PRODUCERS 


For  convenient  reference  the  following  tables  from  another  source  is  here  inserted, 
showing  what  may  be  considered  average  volumetric  analyses  and  the  weight  and  energy 
of  1000  cubic  feet,  of  the  four  types  of  gases  used  for  heating  and  illuminating  purposes: 
APPROXIMATE  COMPOSITION  OF  ORDINARY  GASES 


Composition  by  Volume. 

Natural  Gas. 

Coal  Gas. 

Water  Gas. 

Producer  Gas. 

Anthracite. 

Bituminous. 

CO 

0.50 
2.18 
92.6 
0.31 
0.26 
3.61 
0.34 

6.0 
46.0 
40.0 
4.0 
0.5 
1.5 
0.5 
1.5 
32.0 
735,000 

45.0 
45.0 

2.0 

4.0 
2.0 
0.5 
1.5 
45.6 
322,000 

27.0 
12.0 
1.2 

2.5 
57.0 
0.3 

65.6 
137,455 

27.0 
12.0 
2.5 
0.4 
2.5 
55.3 
0.3 

65.9 
156,917 

H  

CH4  

C,H4  . 

CO,.  . 

N  

O.           

Vapor,  H2O  

Pounds  iii  1000  cu.ft  
B.T.U.  in  1000  cu.ft  

45.6 
1,100,000 

Industrial  Gases. — Their   composition  is   variable.     In 
with  the  nature  of  the  fuel  and  the  method  of  operating, 
indicates  their  general  character: 


artificial    gases   it    varies 
The  following  tabulation 


COMPOSITION  OF   INDUSTRIAL   GASES 
VOLUMETRIC 


Kind. 

C02 

0 

Illu- 
minants 
or  C2H4 

CO 

CH4 

H 

N 

B.T.U. 
per 
Cu.Ft. 

Natural  gas  

0  29 

0.30 

0    15 

0  60 

93  57 

1  40 

2  80 

989 

1  1 

0  60 

0  80 

6  00 

0  60 

67  00 

22  00 

3  00 

892 

Oil  gas                     .        

0  90 

17  40 

58  30 

24  30 

967 

0  50 

16  50 

48  00 

32  00 

3  00 

846 

Illuminating  gas  . 

0  60 

0  10 

3  80 

7  50 

39  50 

46  00 

2  50 

650 

Coke  oven  gas 

2  00 

2  00 

6  00 

35  00 

53  00 

2  00 

620 

-ITT  2             \  Carbureted  . 

1  50 

0  50 

18  50 

19  00 

25  00 

40  00 

4  00 

575 

Water  gas    J±,     „                u»  >  J 

I  "Blue    or  uncarb  r  d  . 

PRODUCER  GASES. 
Anthracite  :  Fuel  

4.25 
3  9 

39.53 
27  3 

1.05 
1.0 

49.50 
12  3 

8.75 
55.5 

295 
147 

Power  

6.2 

26.0 

1.3 

14.4 

52.1 

153 

H 

12  1 

0  2 

18.3 

1.0 

20.5 

47.9 

144 

Suction  ...            .    . 

5  6 

0  6 

24.4 

1.0 

18.0 

50.4 

157 

ii 

6.1 

0  7 

20  2 

1  2 

15.6 

56.2 

136 

Bituminous:   Fuel   . 

5  7 

0  4 

0  6 

22.0 

2.6 

10.5 

58.2 

150 

Power. 

7  9 

23.4 

2.1 

17.1 

49.1 

162 

11 

10  8 

0  5 

16  6 

2.4 

14.9 

54.8 

144 

Mond  gas  .  . 

13  9 

13  8 

2.0 

24.3 

46.0 

153 

Lignite'  Fuel  gas  

6  4 

0  8 

0  7 

22  0 

1.6 

9.6 

58.9 

138 

Power  gas  ... 

9  6 

0  2 

18  22 

4.81 

9.63 

57.53 

148 

Coke'  Power  gas  .  .       .          .    . 

4  8 

27.6 

2.0 

7.0 

58.6 

140 

Suction  gas  .         

5  4 

0  6 

25.3 

0.35 

13.2 

55.15 

136 

Charcoal  '  Fuel  gas.  . 

0  8 

34.1 

0.2 

64.9 

119 

Wood  '  Fuel  gas  ... 

11  5 

0  6 

28  4 

2.9 

0.5 

56.1 

145 

11      a 

6  9 

28.6 

2.2 

8.5 

53.8 

131 

Peat  power  gas  . 

12  4 

0  4 

21  0 

2.2 

18.5 

45.5 

175 

Siemens  .... 

4  2 

24.2 

2.2 

8.2 

61.2 

135 

Blast  furnace  .  .  . 

9  37 

25.84 

0.54 

2.96 

56.0 

105 

CHEMICAL   PROPERTIES   OF    GASES 


223 


Producer   Gas   Analyses. — The  gases  made  in   gas   producers    are    characterized 
by  high  percentage  of  nitrogen,  as  shown  by  the  following  analyses: 

EXAMPLES  OF  PRODUCER  GAS  (SEXTON) 


II 


III 


IV 


Hydrogen 8.60  12.13  10.90  19.43  12.60 

Hydrocarbons 2.40  2.00  1.28  2.66  -3.50 

Carbon  monoxide 24.40  26.40  27.00  16.15  20.40 

Carbon  dioxide 5.20  9.16  4.50  11.53  5.50 

Nitrogen 59.40  50.31  56.32  50.23  58.00 

Combustibles,  per  cent 35.40  40.53  39.18  38.24  36.50 

The  analysis  of  the  gas  made  in  a  producer  by  the  Washburn  &  Moen  Manufacturing 
Co.  is  as  follows: 

C02 4.9 

0 None 

CO 26.8 

C2H4 0.4 

CH4 3.5 

H 18.1 

N 46.3 

ANALYSIS  OF  PRODUCER  WATER  GAS— LOO.MIS-PETTIBONE  PRODUCER 

Sept.  12,  '03  Oct.  9,  '03 

Carbon  dioxide 6.25  8. 76 

Oxygen 0.23  0.95 

Ethylene 0.37  

Carbon  monoxide 27.63  26.20 

Hydrogen 48.37  36.21 

Methane 3.65  4.61 

Nitrogen 13.50  22.32 

Illuminants 0 . 95 

B.T.U.  per  cubic  foot 304  286 

The  lower  carbon  dioxide,  and  higher  hydrogen  and  carbon  monoxide  indicates 
they  are  working  generators  hotter  and  producing  a  higher  grade  of  gas  from  poor 
coal. 

ANALYSIS  OF  MIXED  GAS  (E.  C.  ATKINS) 

Morning  Afternoon 

Nitrogen 57. 78  54.00 

Oxygen 0.33  

Carbon  dioxide 9.20  10.00 

Carbon  monoxide 16.00  16. 15 

Hydrogen 15.12  16.33 

Iliuminants 0.05  0.30 

Methane 1.52  2.80 

Heat  units  per  cubic  foot 125.64  133.6 


224 


GAS   PRODUCERS 


AVERAGE  ANTHRACITE  PRODUCER  GAS 

I.  MADE  WITH  STEAM 
77  cu.ft.  of  this  analysis  were  produced  from  1  Ib.  of  No.  1  buckwheat  coal. 


Component  Gases. 

Heat  Value. 

Kind. 
CO  

Volume, 
Per  Cent. 
27. 
1. 
12. 
3 
57. 

B.T.U. 

87.48 
9.19 
33.36 

Per  Cent 
of  Gas. 
67.3 

7. 
25.7 

Per  Cent  of 
Value  of  Coal. 
57.2 
6. 

21.8 

CH4  

H2. 

C02 

No. 

Total.  . 

100. 

130. 

100. 

85. 

NOTE. — The  producer  gas  of  the  above  analysis  made  with  steam  is  based  on  the  use  of  buck- 
wheat No.  1  coal,  shown  in  table  on  page  8,  and  is  based  on  the  use  of  0.3  Ibs.  of  steam  per  pound 
of  coal.  To  generate  this  amount  of  steam  from  water  at  60°  F.,  there  are  required  335  B.T.U.  or 
only  2.85%  of  the  total  heat  value  of  this  coal. 

II.  MADE  WITH  CARBON  DIOXIDE 
109  cu.ft.  of  this  analysis  were  produced  from  1  Ib.  of  No.  1  buckwheat  coal. 


Component  Gases. 


Heat  Value. 


Kind. 
CO  

Volume, 
Per  Cent. 
30. 

B.T.U. 
97.2 

Per  Cent 
of  Gas. 
90.7 

Per  Cent  of 
Value  of  Coal. 
77.3 

CH4       .  ,    

1. 

9.19 

8.1 

6.9 

H2.  . 

0.4 

1.11 

1.2 

0.8 

CO2 

1. 

No 

67.6 

Total.  . 

100. 

107.5 

100.0 

85.0 

NOTE. — The  value  of  the  B.T.U.  as  given  above  is  based  on  the  temperature  of  the  gas  being 
62°  F.  pressure,  14.7  Ibs.,  and  a  deduction  has  been  made  of  966  B.T.U.  per  pound  of  steam  in  the 
products  of  combustion  on  the  basis  that  the  latent  heat  of  steam  has  no  influence  on  the  heat  value 
of  the  gas  for  all  lines  of  work  for  which  producer  gas  is  used  industrially 

ANALYSIS  OF    A  GAS  FROM  A  SUCTION  PRODUCER 

Carbon  dioxide,  C02 8.0 

Carbon  monoxide,  CO 26 . 0 

Hydrogen,  H 18.5 

Marsh  gas,  CH4 0.5 

Nitrogen,  N ....  47.0 

varying  of  course  with  the  method  of  operation  in  its  proportion  of  H  and  CO. 


CHEMICAL   PROPERTIES   OF   GASES 


225 


TYPICAL  ENGINE  EXHAUST  GAS,  SUCTION  PRODUCER 

02         CO  H2        CH4  N 

1.5         0.6         0.0         0.0         80.9 


Components C02 

Percentage 17.0 


Comparison  of  Producer  and  Illuminating  Gas. — First-class  carbureted  water 
gas,  made  with  4^  gallons  of  Lima  oil  per  1000  feet  of  gas,  c.p.  26^,  contains  730 
B.T.U.  per  cubic  foot. 

In  a  producer  one  pound  of  anthracite  coal  (C  85%,  hydrocarbons  5%,  Ash  10%) 
will  make  about  90  cubic  feet  of  gas  of  following  composition: 

CO  27%,  H  12%,  CH4  1.2%4,  C02  2.5%,  N  57%.  This  gas  contains  about  137 
B.T.U.  per  cubic  foot. 

Therefore  17  cubic  feet  of  carbureted  water  gas  are  equal  in  heat  units  to  gas 
from  one  pound  of  anthracite,  and  1000  cu.ft.  of  carbureted  water  gas  equals  gas 
from  59  Ibs.  of  anthracite. 

Bituminous  Producer  Gas. — This  gas  differs  from  that  made  from  anthracite, 
in  containing  a  much  larger  percentage  of  hydrocarbons.  It  consequently  has  greater 
calorific  energy  and  also  much  more  luminosity.  This  latter  quality  gives  it  special 
value  in  high-temperature  work,  according  to  the  latest  theories  of  combustion.  To 
utilize  these  hydrocarbons  the  gas  must  be  kept  at  a  temperature  that  will  prevent 
their  condensation.  At  the  same  time  it  must  be  borne  in  mind  that  a  very  high 
temperature  will  break  down  the  hydrocarbons,  and  cause  the  deposition  of  soot. 

In  collecting  a  sample  of  gas  for  analysis,  it  is  cooled  to  the  temperature  of  the 
atmosphere,  and  the  hydrocarbons  are  almost  all  condensed.  This  accounts  for  the 
fact  that  while  the  gas  from  bituminous  coal  may  be  doing  50%  more  work  than  the 
gas  from  the  same  amount  of  anthracite,  yet  their  analysis  will  not  differ  materially, 
as  shown  in  the  following: 

AVERAGE  BITUMINOUS  PRODUCER  GAS  ANALYSIS— BY  VOLUME 


European. 


American . 


^onsiiiuems. 

Siemens  Gas. 

Anthracite  Gas. 

Soft  Coal  Gas. 

CO  

*?3  .  7 

27.0 

27.0 

H  

8.0 

12.0 

12.0 

CH4  

2.2 

1.2 

2.5 

CO2  

4.1 

2.5 

2.0 

N  

62.0 

57.3 

56.5 

When  soft  coal  gas  is  passed  through  the  cooling  tube  of  the  old  Siemens  producer, 
or  through  long  unlined  flues,  the  hydrocarbons  are  condensed,  and  the  gas  really 
has  the  composition  as  shown  in  the  preceding  analysis.  A  comparison  of  these 
analyses  with  the  hypothetical  one  given  below,  in  which  none  of  the  hydrocarbons 
are  lost,  shows  the  importance  of  preventing  their  condensation  as  far  as  possible. 

To  examine  more  closely  into  the  conversion  of  bituminous  coal,  a  theoretical 
gasification  of  100  Ibs.  of  coal,  containing  55%  of  carbon  and  32%  of  volatile  com- 


226 


GAS   PRODUCERS 


bustible  (which  is  about  the  average  of  Pittsburg  coal),  is  made  in  the  following  table. 
It  is  assumed  that  50  Ibs.  of  carbon  are  burned  to  carbon  monoxide  and  5  Ibs.  to  carbon 
dioxide;  one-fourth  of  the  oxygen  is  derived  from  steam  and  three-fourths  from  air; 
volatile  combustible  is  taken  at  20,000  heat  units  to  the  pound,  probably  a  safe 
assumption,  notwithstanding  that  a  high  authority  puts  it  at  18,000.  In  computing 
volumetric  proportions,  all  the  volatile  hydrocarbons,  fixed  as  well  as  condensing, 
are  classed  as  marsh  gas,  since  it  is  only  by  some  such  tentative  assumption  that  even 
an  approximate  idea  of  the  volumetric  composition  can  be  formed.  The  energy, 
however,  is  calculated  from  weight,  and  is  strictly  correct: 

GASIFICATION  OF  BITUMINOUS  COAL 


Producer  Reaction. 

Products. 

Pounds. 

Cubic  Feet. 

Per  Cent 
by  Vol. 

50  Ibs  C  burned  to.  ...             

CO 

116.66 
18.33 
32.00 
2.5 
200.70 

1580.7 
157.6 
746.2 
475.0 
2709.4 

27.8 
2.7 
13.2 
8.3 
47.8 

5  Ibs  C  burned  to  .        ... 

.    .                      CO2 

32  Ibs  vol  HC  (distilled)  

80  Ibs.  O  are  required,  of  which  20  Ibs.  derived 
60  Ibs.  O,  derived  from  air,  are  associated  wii 

Total  

from  H2O,  liberate  H 
th  N 

370  .  19 

5668.9 

99.8 

Energy  in  116 .56  Ibs.  CO 504,554  heat-units 

Energy  in  2 .00  Ibs.  vol.  HC 640,000          " 

Energy  in  32 .50  Ibs.  H 155,000          " 


Total 1,299,554 

Energy  in  coal , 1,437,500 

Per  cent  of  energy  delivered  in  gas 90 .0 

Heat-units  in  one  pound  of  gas 3484 .0 

Heat-units  in  one  cubic  foot  of  gas 229 . 2 

When  these  figures  are  compared  with  the  theoretical  gasification  of  anthracite, 
the  vastly  greater  energy,  both  by  weight  and  volume,  in  the  bituminous  gas,  is  seen 
at  once.  It  is  worth  even  more  in  practice  than  appearance  indicates,  since  the  high 
percentage  of  hydrocarbons  is  associated  with  lower  nitrogen.  All  of  the  32%  of 
volatile  combustible,  except  the  tarry  matter,  must  be  volatilized  and  utilized  in  its 
full  strength,  whether  it  be  fixed  gas  or  simply  distilled  hydrocarbon.  For  this  purpose 
it  should  not  be  suffered  to  cool  below  300°  before  it  enters  the  combustion-chambers 
or  regenerators — the  higher  its  temperature  at  the  furnace  the  better. 

The  comparative  value  of  the  two  gases  in  high-temperature  work  is  illustrated 
by  the  fact  that  when  anthracite  gas  is  used  in  regenerative  furnaces  for  heating  iron, 
it  is  frequently  necessary  to  gasify  in  the  producers  from  two  to  three  times  more 
coal  per  ton  of  iron  heated  than  wnen  bituminous  gas  is  used.  It  is  also  well  known 
that  the  rate  and  effectiveness  of  heating  rises  with  the  percentage  of  volatile  com- 
bustible. The  results  may  prove  that  it  can  be  used  advantageously,  especially  when 
supplemented  with  a  little  oil,  which  could  be  introduced  into  the  furnace  about  where 
the  air  and  gas  unite,  and  thus  secure  a  luminous  hydrocarbon  flame.  Such  use  of 
oil  is  said  to  be  practiced  to  a  limited  extent  in  Europe,  as  a  supplement  to  water  gas. 


CHEMICAL   PROPERTIES   OF   GASES 


Broadly  speaking,  and  for  a  wide  field  of  work,  the  quality  of  the  heating  that  has 
been  done  with  anthracite  gas  is  good.  The  comparison  with  bituminous  gas  is  not 
always  as  unfavorable  as  the  one  we  have  considered.  The  energy  of  the  bituminous 
gas  described  was  3484  heat  units  per  pound,  as  against  2246  heat  units  for  the 
anthracite;  but  most  bituminous  coals  are  lower  in  volatile  combustible  and  higher 
in  carbon  than  our  specimen  coal.  Possibly  a  fair  average  would  be  70%  of  fixed 
carbon  and  20%  of  hydrocarbon  with  10%  of  ash.  A  theoretical  gasification  of  100 
Ibs.  of  such  coal,  burning  5  Ibs.  of  carbon  to  carbon  dioxide,  and  deriving  one-fourth 
of  the  oxygen  from  water  and  three-fourths  from  air  would  show  this  result: 

AVERAGE  BITUMINOUS  COAL  YIELD 


Products. 

Pounds. 

Cubic  Feet. 

Per  Cent 
by  Vol. 

65  Ibs 

C  burned  to  

CO 

151.6 

2054 

30.8 

5  Ibs 

C  burned  to  

.  .CO, 

18.3 

157 

2.3 

20  Ibs 

vol   HC  (distilled)  

20  0 

466 

7.0 

95  Ibs 

O   from  water  liberate 

.    .     H 

.3  1 

588 

9  0 

75  Ibs 

atmosphere  O  mixed  with  

N 

251  2 

3391 

50  9 

Total  

444  .  2 

6656 

100.0 

Calorific  energy  of  the  gas 1,247,870  heat-units 

Calorific  energy  of  the  gas  per  pound 2,809 

Calorific  energy  of  the  gas  per  cubic  foot 187 .4      " 

Calorific  energy  of  the  coal 1,415,000          " 

Efficiency  of  the  conversion 88  per  cent 

Anthracite  Producer  Gas. — In  considering  the  gasification  of  anthracite  coal 
we  find  in  it  a  volatile  combustible,  varying  in  quantity  from  1.5  to  over  7%,  and  while 
its  flame  resembles  that  of  hydrogen,  the  amount  of  marsh  gas  found  in  anthracite 
producer  gas  corresponds  practically  with  the  total  volatile  hydrocarbons  in  the  coal. 
If  this  is  correct,  all  the  hydrogen  in  the  gas  is  derived  from  the  dissociation  of  water- 
vapor;  but  this,  as  previously  shown,  is  in  practice  higher  than  the  theoretical  quantity. 
We  generally  find  1.5%  or  more  of  marsh  gas  in  anthracite  gas  made  from  coal  con- 
taining about  5%  of  volatile  combustible,  and  this  proportion  is  about  what  should 
be  expected  if  all  the  volatile  combustible  in  the  coal  is  marsh  gas.  But  if  it  is  not,  it 
is  difficult  to  explain  the  presence  of  the  marsh  gas  and  the  excess  of  hydrogen  in  the 
producer  gas.  If  the  percentage  of  carbon  dioxide  were  high  and  the  resulting  excess 
of  heat  were  expended  in  an  increased  dissociation  of  steam,  that  would  account  for 
the  hydrogen;  but  with  low  carbon  dioxide,  and  all  the  volatile  combustible  repre- 
sented by  marsh  gas  in  the  producer  product,  it  is  difficult  to  account  for  all  the 
hydrogen  in  the  face  of  our  assumption  that  we  cannot  gasify  with  steam  more  than 
one-quarter  of  the  carbon. 

If  we  felt  confident  that  solid  carbon  and  marsh  gas  were  the  only  combustibles 
to  be  considered  in  anthracite,  it  would  be  easy  to  calculate  from  an  analysis  of  producer 
gas  the  amount  of  energy  derived  from  the  coal,  as  is  shown  in  the  following  theoretical 
gasification  made  of  coal  with  assumed  composition:  Carbon,  85%;  volatile  hydro> 


228 


GAS   PRODUCERS 


carbons,  5%;  ash,  10%;  80  Ibs.  carbon  assumed  to  be  burned  to  carbon  monoxide; 
5  Ibs.  carbon  burned  to  carbon  dioxide;  three-fourths  of  the  necessary  oxygen  derived 
from  air,  and  one-fourth  from  water. 

TYPICAL  ANTHRACITE  PRODUCER  REACTION 


Producer  Reaction. 

Products. 

Pounds. 

Cubic  Feet. 

Anal,  by  Vol. 

80  Ibs. 
51bb. 
5  Ibs. 
120  Ibs. 
90  Ibs. 

1 

C  burned  to.  . 

CO 

186.66 
18.33 
5.00 
3.75 
301  .05 

2529.24 
157.64 
116.60 
712.50 
4064  .  17 

33.4 
2.0 
1.6 
9.4 
53.6 

C  burned  to.  . 

.  .CO, 

vol.  HC  (distil 
oxygen  are  rec 
from  air  are  as 

total  

led)  

uired,  of  which  30  Ibs. 
sociated  with  .  . 

from  H2O  liberate  H 

N 

514.79 

7580.15 

100.0 

Energy  in  the  above  gas  obtained  from  100  Ibs.  anthracite: 

186 .66  Ibs.  CO 807,304  heat-units 

5.00  Ibs.  CH4 117,500 

3 .75  Ibs.  H 232,500 


1,157,304 

Total  energy  in  gas  per  pound 2,248 

Total  energy  in  gas  per  cubic  foot 152 .7 

Total  energy  in  100  Ibs.  of  coal 1,349,500 

Efficiency  of  the  conversion 86  per  cent 

It  will  be  noticed  that  1.6%  of  marsh  gas  represents  all  the  volatile  combustible 
in  the  coal,  and  that  86%  of  the  total  energy  is  delivered  in  the  gas;  but  the  sum  of 
carbon  monoxide  and  hydrogen  exceeds  the  results  obtained  in  practice.  The  sensible 
heat  of  the  gas  will  probably  account  for  this  discrepancy,  and  it  is  quite  safe  to  assume 
the  possibility  of  delivering  at  least  82%  of  the  energy  of  anthracite. 

To  illustrate  the  loss  caused  by  forming  carbon  dioxide  in  the  producer,  when 
none  of  the  heat  of  primary  combustion  is  used  for  dissociating  water,  the  following 
theoretical  gasifications  of  carbon  are  adduced,  showing  the  resulting  gases,  in  which 
0,  5,  10,  15,  25  and  50%  of  carbon  are  successively  burned  to  carbon  dioxide,  and 
giving  the  percentage  of  energy  delivered  in  each  case,  without  considering  the 
increasing  proportion  of  nitrogen  as  a  factor  in  reducing  the  energy-ratio  of  the  poorer 

gases. 

EFFECT  OF  BURNING  TO  CARBON  DIOXIDE 


C  burned  to  CO2  

0% 

5% 

10% 

15% 

25% 

50% 

Products  : 
CO  per  cent  

34.4 

31.5 

29.5 

26.6 

22.7 

12.9 

CO2  per  cent  

1.6 

3.2 

4.6 

7.6 

12.9 

N  per  cent  

65.6 

66.9 

67.3 

68.8 

69.7 

74.2 

Pounds  of  gas  

679 

708 

737 

766 

824 

969 

Cubic  feet  of  gas  

9183 

9468 

9759 

10,065 

10,387 

12,189 

Per  cent  of  carbon  energy  in  gas  
Heat-units  per  cubic  foot  of  gas  

70 
109.7 

66 
100.5 

63 
94.1 

59 

85.8 

52* 
72.04 

35 
41.1 

CHEMICAL   PROPERTIES  OF  GASES 


229 


But  the  formation  of  carbon  dioxide  in  the  producer  is  objectionable,  not  only 
when  the  heat  of  its  combustion  is  lost,  but  even  when  a  large  portion  of  this  heat 
is  recovered  by  dissociating  water.  A  theoretical  gasification,  in  \vhich  100  Ibs.  of 
carbon  are  completely  burned  to  carbon  dioxide,  and  70%  of  the  resulting  heat  of 
combustion  (1,450,000  heat  units)  is  assumed  to  be  recovered  by  dissociating  water, 
is  illustrated  in  the  following  table: 

COMBUSTION  FOR  DISSOCIATION 


Products. 

Producer  Reaction. 

Pounds. 

Cubic  Feet. 

Per  Cent 
by  Vol. 
(Approx.) 

100  Ibs  C  burned  to  CO2 

366.66 

3,153 

25 

70  per  cent  of  1,450,000  heat-units  is  1,015,000  units,  which 
liberate  from  water  H 

16.34 

3,110 

25 

130  .96  Ibs.  O,  liberated  from  this  water,  combines  with  49  .2  Ibs. 
C  to  form  CO2.     This  leaves  50.8  Ibs.  C  to  combine  with 
135  13  Ibs  atmospheric  O,  which  is  associated  with.  ...     N 

453 

6,115 

50 

Total  

836.00 

12,378 

100 

Here  we  have  only  25%  of  combustible  hydrogen,  representing  70%  of  the  carbon 
energy,  in  836  Ibs.,  or  12,378  cu.ft.  of  gas;  the  latter  is,  therefore,  of  poor  quality,  and 
compares  very  unfavorably  with  the  70%  conversion  of  the  all-monoxide  gas  in  the 
preceding  table,  where  34.4%  of  combustible  (carbon  monoxide)  are  found  in  679  Ibs., 
or  9138  cu.ft.  of  gas.  It  follows  that  whenever  carbon  dioxide  is  formed  and  its  heat 
used  for  dissociating  water,  there  is  at  best  but  a  poor  utilization  of  the  energy. 
Probably  all  that  can  be  recovered  in  this  way  does  not  exceed  one-half  of  what  may 
be  obtained  from  carbon  burned  to  carbon  monoxide.  But  in  special  cases  where 
practically  all  the  sensible  heat  of  the  gas  is  utilized  in  a  non-regenerative  furnace 
or  kiln,  where  mechanical  difficulties  effectually  prevent  good  combustion,  a  very 
hot  gas,  containing  7  to  9%  of  carbon  dioxide  is  found  to  be  preferable  to  a  cold  gas 
low  in  carbon  dioxide. 

Power  Gas. — There  are  some  properties  of  producer  gas  which  are  of  special 
importance  when  used  in  gas  engines,  as  shown  in  the  following  tables: 

AVERAGE  GAS  ANALYSIS  TAKEN  AT  NATIONAL  METER  CO.  GAS  ENGINE  TEST  OF 
GAS  FROM  A  REGULAR  R.  D.  WOOD  GAS-PRODUCER  SYSTEM 


B.H.P. 

B.T.U. 
by 
Calori- 
meter. 

Time. 

CO2. 

02. 

CO. 

H;. 

CH«. 

B.T.U. 

Calculated 
by 
Analysis. 

N. 

Remarks. 

A.M. 

100 

147 

10.45 

3.5 

1.9 

23 

13 

2.1 

139 

56.5 

100 

138 

11.45 

4.6 

1.5 

23.8 

15.5 

1.1 

139.2 

53.5 

100 

134 

12.45 

6.8 

1.1 

17.8 

15.0 

2.0 

129 

57.3 

100 

132 

1.45 

6.5 

1.2 

18.6 

15.5 

0.7 

118.4 

57.5 

75 

125 

2.45 

8.1 

1.3 

15.9 

12.5 

1.1 

103.7 

61.1  | 

Engine 
back-firing 

100 

141 

3.45 

4.5 

1.1 

22.7 

15.5 

1.7 

141.8 

54.5 

100 

135 

4.45 

6.5 

1.2 

16.6 

18.5 

.7 

121.7 

56.5  { 

Engine 
pre-igniting 

4.45 

17.0 

1.5 

0.6 

0.0 

0.0 

80.9 

Exhaust 

230 


GAS   PRODUCERS 


V 

I's^J 

pll 

i—  i 

0> 

00 

us 

0 

tO         <N 

N 

CO 

*• 

" 

General  Characteristics  for  Power  Work. 

;al  power  gas.  Rich,  pure,  rather  slow  burning. 

Requires  no  cleaning, 
ry  rich  in  heavy  hydrocarbons.  Liable  to  car- 
bon deposits.  Seldom  used  for  power  except 

in  small  oil  (petrol)  engines. 
:cellent  gas,  resembling  natural  gas.  Not  hard 
to  clean.  Manufacturing  costs  usually  too  high 

Js  of 
8-T3 

O    o3 

|W 

It 

TO     .^H 

Q  J3 

.    bC  t, 

SR    G    CU 

CO     *^H         — 

all 

&^  * 

fe  §  -rs 
o  2  § 

—    *T3      fi 

i-  J3    bC 
0    to    c 

"     03  "* 

requiring  much  purification, 
re  gas,  too  snappy  (high  in  H)  for  gas  engines. 
More  suitable  if  enriched  with  oil  gas.  Rather 

expensive  gas  for  general  power  purposes, 
ch  gas,  high  in  H,  and  rather  snappy.  Free  from 
impurities,  except  S.  Manufacturing  cost  low. 
eapest  and  best  of  artificial  fuel  gases,  lean  and 
comparatively  slow  burning.  Made  from  any 
grade  fuel. 

chest  of  producer  gases.  Tar  distillate  diffi- 
cult to  remove.  Most  grades  of  coal  suitable, 

3 
p 

cT 

bC 

"E 

s  free  from  tar,  requiring  little  cleaning.  Ex- 
cellent power  gas.  Buckwheat  size  coal  may 
be  used. 

s  practically  clean,  except  dust.  Most  suitable 
for  small  producers.  Fuel  rather  expensive. 

s  very  lean,  dusty,  and  sluggish.  Difficult  to 
clean  except  mechanically.  Excellent  gas  for 
engines  taking  high  compression. 

o> 

M 

o3 

03 

03 

T3 
HH 

H 

O 

£ 

tf       0 

S 

O 

O 

O 

03 

bC 

O> 

13 

• 

bC 
t-, 
3 

45 

03 

retorts. 

chambers 

6 
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of  volatiles  of  coal 
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C  S 
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nj 

G^ 

O    G 

*T^     fli 

""      '3'a.s 
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Some  CO  2  formed 
i  coal.  Breaking  u 
and  conversion  o; 

coal.  Practically 
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Is 
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CHEMICAL   PROPERTIES   OF   GASES 
CONSTITUENTS  OF  POWER  GASES  WITH  GENERAL  PROPERTIES 


231 


Gas. 

Heating  Value. 

Characteristics,  Where  Found. 

Nanic. 

Chemical 
Symbol. 

B.T.U., 
CubicFeet, 

Net. 

Relative. 

Hydrogen  

H 
O 
N 
CO 
C02 
CH4 

C2H2 
C2H4 

C2H6 
C,jH6 

C 

s 

278 
0 
0 
326 
0 
913 

1427 
1490 
1615 
3655 

1 

Element,  formed  from  decomposition  of  steam 
(H2O)  or  hydrocarbon  compounds.       Burns 
very  rapidly  with  high  flame  temperature. 
Element,  not  considered  a  combustible,  as  it 
displaces  an  equal  amount  of  O  in  air  for 
combustion. 
Element,  inert  gas  entering  with  air  (N  79%  ; 
O  21%).     Retards  speed  of  combustion. 

Valuable  constituent.      Product  of  incomplete 
combustion  (oxidation)  of  C  in  presence  of 
excess  carbon. 
Inert  gas.     Product  of  complete  combustion  of 
C.      Occurs  in  all  producer  and  blast  gases. 
Retards  speed  of  combustion. 
Most  valuable  constituent  evolved  by  natural 
or  artificial  decomposition  of  vegetable  mat- 
ter, coal,  or  crude  oils. 
r  Higher    hydrocarbons,    usually    as    "illumi- 
nants,  "   occur  in  small  quantities  in   the 
richer  gases   liberated   during   destructive 
distillation  of  coal  or  oil.     Acetylene  used 
I.      alone  for  lighting. 
C  oxidizes  to  CO  (incomplete)  and  CO2  (com- 
plete).    CO  oxidizes  to  CO2. 
S  oxidizes  to   SO2  forming  H2SO4   (sulphuric 
acid)  with  water. 

Oxv^en 

Nitrogen   .  . 

Carbon    monoxide    or 
carbonic  oxide  

1.17 

Carbon  dioxide 

Methane  or  marsh  gas.  .  . 
Acetylene  

3.29 

51.4 
53.6 
58.1 
131.5 

Ethylene  or  Olefiant  gas  . 
Ethane  

Benzene  or  benzol  

Carbon   .  . 

Sulphur  

Blending  Producer  Gas  with  Coal  Gas. — Harold  G.  Coleman  (Journal  of  Gas 
Lighting,  September  18,  1906,  p.  754)  says  that  the  blending  of  producer  gas  with 
the  coal  gas  made  in  the  ordinary  way  of  gas  manufacture,  thus  increasing  the  total 
volume  of  gas  made  into  "  a  consistent  bulk  or  whole,"  produces  a  coal  gas  of  about 
110  to  125  B.T.U.  per  cubic  foot.  Assuming  that  a  ton  of  coal  gives  11,000  cu.ft.  of 
gas  of  570  B.T.U.,  and  that  1000  cu.ft.  of  producer  gas  of  120  B.T.U.  be  added,  the 
resultant  mixture  would  be  12,000  cu.ft.  of  532  B.T.U.  gas. 

To  offset  this,  however,  allowance  must  be  made  for  the  calorific  value  of  the 
hydrocarbon  vapors  retained,  and  which  would  otherwise  be  carried  away  by  the  tar. 
This  cannot  be  given  exactly,  but  from  tests  made  with  tars  such  as  are  produced 
from  coal  affording  the  aforesaid  yield,  it  would  appear  as  if  the  vapor  retained 
(mainly  benzene)  will  not  exceed  1%  of  the  producer  gas  added.  This  would  amount 
to  10  ft.  of  vapor,  increasing  the  above  yield  to  12,010  cu.ft.  of  gas  of  535  B.T.U.  gross. 

Assuming  the  costs  of  the  illuminating  and  producer  gases  to  be  24.3  cents  and 
1.5  cent  per  1000  cu.ft.  respectively,  the  resultant  price  of  the  mixed  gas  will  be  22 
cents.  With  a  selling  price  of  60  cents  per  1000,  this  would  mean  a  reduction  in  price 
of  3%,  and  a  reduction  in  calorific  value  of  6%.  The  reduction  in  flame  temperature 
will  also  be  considerable,  although  this  can  only  be  determined  by  direct  experiment.. 


232  GAS   PRODUCERS 

Water  Gas. — There  is  much  more  literature  at  our  command  on  water  gas  than 
on  producer  gas.  It  is  made,  as  is  well  known,  in  an  intermittent  process,  by  blowing 
up  the  fuel  bed  of  the  producer  with  air  to  a  high  state  of  incandescence  (and  in  some 
cases  utilizing  the  resulting  gas,  which  is  a  lean  producer  gas),  then  shutting  off  the 
air  and  forcing  steam  through  the  fire,  which  dissociates  the  steam  into  its  elements 
of  oxygen  and  hydrogen,  the  former  combining  with  the  carbon  of  the  coal,  and  the 
latter  being  liberated. 

This  gas  can  never  play  a  very  important  part  in  the  industrial  field,  owing  to 
the  large  loss  of  energy  entailed  in  its  production;  yet  there  are  places  and  special 
purposes  where  it  is  desirable,  even  at  a  great  excess  in  cost  per  unit  of  heat  over 
producer  gas;  for  instance,  in  small,  high-temperature  furnaces,  where  much  regenera- 
tion is  impracticable,  or  where  the  "  blow-up  "  gas  can  be  used  for  other  purposes 
instead  of  being  wasted.  Some  steel  melting  has  been  done  in  Europe  with  this  gas, 
under  the  claim  that  much  more  work  can  be  gotten  out  of  a  furnace  in  a  given  time 
owing  to  the  greater  eneigy  of  the  gas,  so  that  the  extra  cost  is  more  than  balanced. 
The  lack  of  luminosity  (hydrocarbon  flame)  in  water  gas  makes  this  doubtful,  unless 
some  oil  is  introduced  into  the  furnace,  as  before  described. 

We  will  now  consider  the  reactions  and  the  energy  required  in  the  production  of 
1000  ft.  of  water  gas,  which  is  composed,  theoretically,  of  equal  volumes  of  carbon 
monoxide  and  hydrogen. 

Pounds. 

500  cu.ft.  of  H  weigh 2 . 635 

500  cu.ft.  of  CO  weigh 36.89 


Total  weight  of  100  cu.ft 39.525 

Now,  as  carbon  monoxide  is  composed  of  12  parts  carbon  to  16  of  oxygen,  the 
weight  of  carbon  in  36.89  Ibs.  of  the  gas  is  15.81  Ibs.  and  of  oxygen  21.08  Ibs.  When 
this  oxygen  is  derived  from  water  (steam)  it  liberates,  as  above,  2.635  Ibs.  of  hydrogen. 
The  heat  developed  and  absorbed  in  these  reactions  (disregarding  the  energy  required 
to  elevate  the  coal  from  the  temperature  of  the  atmosphere  to  say  1800°)  is  as  follows: 

Heat-units. 

2.635  Ibs.  H  absorb  in  dissociation  from  water  2.635X62,000.  .  =163,370 
15.81  Ibs.  C  burned  to  CO  develop  15.81  X4400 =  69,564 


Excess  of  heat-absorption  over  heat-development =  93,806 

The  loss  due  to  this  absorption  must  be  made  up  in  some  way  or  other,  while 
6.47  Ibs.  of  carbon  burnt  to  carbon  dioxide  would  supply  this  heat,  theoretically, 
but  in  practice,  owing  to  the  imperfect  and  indirect  combustion  and  radiation,  more 
than  double  this  amount  is  required.  Besides  this,  it  is  not  often  that  the  sum  of  the 
carbon  monoxide  and  hydrogen  exceed  90%,  the  remainder  being  carbon  dioxide 
and  nitrogen. 


CHEMICAL   PROPERTIES    OF    GASES  233 

Blast-furnace   Gas. — The  gases  from  an  iron  blast  furnace  contain  on  an  average, 

Per  cent. 

Carbon  dioxide 12 

Carbon  monoxide 23 

Hydrogen 2 

Methane • 2 

Water  vapor 3 

Nitrogen 58 

The  efficiency  of  the  utilization  of  this  gas  in  gas  engines  could  be  greatly  improved 
even  by  the  simple  removal  of  the  high  content  of  carbon  dioxide,  as  in  any  operative 
apparatus  in  which  a  combustible  gas  containing  a  reactive  proportion  of  carbon 
dioxide  may  be  passed  through  a  bed  of  ignited  fuel  in  such  a  manner  that  the  com- 
bustible gas  first  comes  into  contact  with  the  latest  charged  layer  of  the  fuel,  fully 
answers  the  requirements. 

Blast  Furnace  Gas  Power. — In  a  discussion  of  gas  power  for  rolling  mills,  Dr. 
Franz  Erich  Junge-Hermsdorf  says: 

"If  a  blast  furnace  is  shut  down,  either  on  account  of  a  depression  on  the  money 
market  or  for  showing  signs  of  distress,  the  gas  producer  may  be  drawn  upon  to  deliver 
the  required  energy  to  stoves,  engines,  boilers,  etc.  Also  when  there  is  need  of  higher 
blast  pressures,  as  sometimes  happens.  With  steam-blowing  engines,  it  is  easier  to 
get  sufficient  pressure  on  when  gas  is  used  under  the  boilers  than  when  direct  coal 
firing.  Also,  with  gas  firing,  the  efficiency  of  coal  conversion,  or  the  calorific  effect 
attained  is  from  5  to  25%  greater  and  the  labor  is  less.  Producer  gas,  moreover, 
permits  at  all  times  of  perfect  control,  allowing  less  variation  in  the  amount  of  air 
blown  through  the  furnace,  thus  giving  greater  regularity  of  product.  By  regenerating 
blast  furnace  gas  with  the  aid  of  producer  gas  of  higher  heat  value,  the  plant  fuel 
consumption  can  be  reduced  to  about  40%  of  the  ordinary.  (When  steel  furnaces 
are  fired  with  ordinary  gas,  rolling  mills  being  driven  by  steam  power  and  heating 
stoves  being  fired  with  coal,  then  the  total  consumption  runs  up  to  about  100%  of  the 
finished  product.)  The  scheme  of  installing  reserve  gas  producers  is  now  being  gener- 
ally recommended,  allowing  of  concentration  and  control  of  fuel  conversion  at  one 
central  place  with  all  resulting  advantages  and  growing  the  more  efficient  the  larger 
the  plant.  Regenerating  the  blast  furnace  gas  with  producer  gas  renders  it  at  once 
useful  for  firing  steel  furnaces,  and  at  the  same  time  eliminating  the  irregularity  of 
its  composition,  which  varies  between  85  and  106  B.T.U.,  thus  making  it  better  fit 
for  gas  power  work,  for  the  engines  grow  smaller  in  size  or  higher  in  capacity  the 
greater  the  calorific  value  of  the  gas  used." 

However,  a  comparison  of  total  heat  used  by  either  gas-engine  power  or  steam 
gas  generated  turbine  power,  will  show  a  heat  consumption  upon  the  part  of  the 
latter  of  about  50%  higher  than  where  the  gas  is  used  in  the  engine  directly,  the 
figures  showing  about  7580  calories  per  kilowatt  hour,  with  steam  power,  and  about 
5050  calories  with  the  gas  engine. 

"The  consumption  per  indicated  horse-power  in  gas  engines  is  here  figured  as  3 
cubic  meters,  the  blast  furnace  gas  having  an  average  calorific  value  of  900  calories 


234  GAS   PRODUCERS 

per  cubic  meter,  the  engine  efficiency  being  assumed  as  0.8  and  the  mean  efficiency 
of  the  generator  as  0.915,  giving  a  consumption  of  5020  calories  per  kilowatt-hour 
for  gas  power,  under  the  above  outlined  conditions." 

It  must  be  understood  that  the  above  figures  are  based  upon  a  mean  and  highly 
fluctuating  load,  the  efficiency  in  favor  of  direct  gas-power  generation  being  75  to  100% 
at  full  load.  It  is  necessary  to  provide  for  both  variations  in  value  of  blast  gas  and 
also  to  take  care  of  temporary  over-loads,  by  installing  engines  of  plus  normal  capacity. 
According  to  H.  Wild,  for  steel  plants  service,  the  gas  engine  should  have  a  capacity 
of  1 .8  that  of  the  steam  engine  rating.  As  a  protection  against  irregularities  in  gas  and 
to  take  care  of  over  loads. 

Carbon  Dioxide  in  Gas. — As  is  well  known  the  presence  of  any  large  amount 
of  carbon  dioxide  in  a  combustible  gas — particularly  in  a  gas  intended  for  use  in  an 
internal-combustion  engine — has  a  very  injurious  effect  upon  the  calorific  power  of 
the  gas.  This  is  due  to  two  causes,  first,  the  high  specific  heat  of  the  carbon  dioxide 
causes  the  absorption  of  a  large  amount  of  the  heat  developed  in  the  combustion  of 
the  gas.  Secondly,  the  already  formed  carbon  dioxide  has  a  tendency  to  diminish 
the  completeness  of  the  combustion  of  the  gas.  This  is  due  to  the  fact  that  the  avidity 
of  carbon  monoxide  for  oxygen  diminishes  with  the  increase  in  the  vapor  tension  of 
the  carbon  dioxide  formed.  When  we  start  our  combustion,  therefore,  in  the  presence 
of  a  large  amount  of  carbon  dioxide,  and  hence  in  an  atmosphere  in  which  the  vapor 
tension  of  that  component  of  the  gas  is  high  to  start  with,  the  energy  and  velocity  of 
the  oxidizing  reaction  is  much  lessened.  The  combustion  is,  so  to  speak,  dampened 
and  rendered  sluggish.  Therefore,  unless  the  conditions  under  which  the  combustion 
is  made  to  take  place  are  highly  favorable,  it  is  liable  to  be  incomplete.  If  the  tem- 
perature of  the  reaction  is  low — as  when  the  gas  is  burned  in  contact  with  the  com- 
paratively cool  tubes  of  a  boiler — or,  if  the  time  of  exposure  of  the  gases  to  the  reacting 
temperature  is  short — as  is  the  case  again  in  boiler  practice — the  combustion  is  sure 
to  be  very  incomplete. 

In  internal  combustion  engines,  the  disadvantages  mentioned  are  particularly 
marked.  The  specific  retarding  effect  exerted  by  carbon  dioxide  on  the  velocity  of 
propagation  of  the  flame  through  an  explosive  mixture  in  the  cylinder  of  a  gas  engine, 
necessitates  the  advancing  of  the  spark  to  the  furthest  practical  limit.  If  now, 
the  content  of  carbon  dioxide  in  the  gas  should  suddenly  drop,  we  are  liable  to  get 
pre-ignition  of  the  charge  with  the  consequent  loss  of  economy,  racking  of  the  engine, 
and,  in  some  cases,  running  backward  of  the  engine  with  the  liability  to  accident 
which  that  entails.  Even  where  the  gas  maintains  a  uniform  proportion  of  carbon 
dioxide,  the  slowness  of  the  combustion,  of  necessity,  entails  a  great  waste  of  energy, 
particularly  with  any  high  speed  engine.  The  efficiency  of  a  gas  engine  depends  upon 
the  difference  between  the  maximum  temperature  developed  by  the  explosion  and 
the  temperature  of  the  exhaust  gases. 

When  the  gas  is  high  in  carbon  dioxide,  the  combustion  is  so  slow  that  the  piston 
has  covered  part  of  its  forward  stroke  before  the  combustion  is  complete.  The  result 
is  that  the  initial  temperature  is  low,  the  expansion  is  shortened,  and  the  efficiency 
of  the  engine  consequently  lowered. 

For  all  these  reasons  it  is  highly  desirable  in  gas  engine  work,  to  have  as  little 
carbon  dioxide  in  the  gas  as  possible. 


CHEMICAL   PROPERTIES   OF   GASES 


235 


To  aacertain  Ion  in  fuel  find  junction  between  temperature  line  at  bottom  and  CO,  at  right  hand ;  the  Ogam 
at  left  hand  give  the  lota  without  any  calculations  allowing  the  air  entering  the  furnace  to  be  80°  7. 

3  —Flue  temperature  600°,  flue  gae  10%,  COi    Follow  10%  line  to  junction  with  800°  (perpendicular  line) 


temnerat 


etraight  line  to  left  when  the  loai  ia  ahowo  15  3% 


FIG.  104. — Diagram  showing  the  loss  of  Fuel  in  Fuel  Gas  under  different  conditions. 


236 


GAS   PRODUCERS 


EXCESS  OF  AIR  CORRESPONDING  TO  GIVEN  PERCENTAGE  OF  CO2  IN  FLUE  GASES 

FROM  DIRECT  COMBUSTION 


CO2.  Soft  Coal. 

18% none 

16     It 

14     If 

12     It 

11     1  t7T 

10     If 

9  2 


Hard  Coal. 


21 

24 

W7 

3 

31 


2 

2* 
2* 

2| 


The  following  table  gives  the  percentage  of  the  total  heat  value  of  the  coal  repre 
sented  by  varying  amounts  of  CC>2  in  producer  gas,  according  to  Campbell  (manu 
facturer  of  iron  and  steel): 


C02  per  cent.  ..       23456 
Loss  per  cent.  ..     5.3     8.0     10.8     13.7     16.6 


78 
19.6     23.0 


9 
26.5 


10 
30 


PERCENTAGE  OF  FUEL  LOST 


There  is  always  a  certain  amount  of  CO2  formed,  even  in  the  best  producer 
practice;  in  fact,  it  is  inevitable,  and  if  kept  within  proper  limits  does  not  constitute 
a  net  loss  of  efficiency,  especially  with  very  short  gas  flues,  because  the  energy  of  the 
fuel  so  burned  is  represented  in  the  sensible  heat  or  temperature  of  the  gas,  and  results 

in  delivering  a  hot  gas  to  the  furnace.  However, 
the  loss  increases  rapidly  above  4%  of  C02  even 
when  the  gas  is  carried  hot  in  short  flues.  If  too 
hot,  the  hydrocarbons  are  broken  up  and  deposit 
their  carbon  as  soot,  and  the  loss  from  radiation 
is  very  great.  If  attempt  is  made  to  run  too  cool, 
by  increasing  the  proportion  of  steam,  the  result 
is  equally  bad,  as  a  low  gas  temperature  permits 
the  deposition  of  tar  in  the  flues,  and  both  the 
heating  value  and  capacity  are  largely  reduced. 
The  best  result  is  at  about  4%  CO2,  a  gas 
temperature  between  1100°  and  1200°  F.,  and 
flues  less  than  100  ft.  long. 

The  accompanying  diagram  shows  how  fuel 
loss  increases    as   percentage    of  CO2  decreases 
in  stack  or  exhaust  gases. 
Vapor  Saturation.  —  In  an  elaborate  set  of  tests  made  for  the  U.  S.  Government 
by  Professor  C.  E.  Lucke  and  S.  M.  Woodward  on  the  use  of  alcohol  in  gas  engines, 
the   following    vapor  tensions   of    saturation    for   various    liquids   in    millimeters    of 
mercury  are  given: 


1 

) 

2( 

3< 

) 

4 

) 

a 

3 

(X 

) 

7C 

« 

) 

9C 

IOC 

• 

: 

^ 

>- 

• 

* 

^ 

• 

,-T 

•*• 

">     i 

FU 

-I 

§ 

ST 

^ 

*-* 

°  ' 

: 

/ 

u,      5 

3        C 

/ 

*      7 

/ 

•z      7 

? 

• 

/ 

9 

'• 

/ 

°    U 

' 

/ 

FU 

;L 

US 

ED 

u,    U 

I 

£    18 

I 

I 

a    IB 

/ 

/ 

/ 

20 

f 

FIG.  105. — Relation  of  CO^  to  Heat  Loss. 


CHEMICAL   PROPERTIES   OF   GASES 
VAPOR  TENSION  AT  GIVEN  TEMPERATURES 


237 


Temperature, 

Pure  Ethyl  Alcohol. 

Pure  Methyl 
Alcohol. 

Water. 

Gasoline. 

Degree  C. 

Degree  F. 

0 

32 

12 

30 

5 

99 

5 

41 

17 

40 

7 

115 

10 

50 

24 

54 

9 

133 

15 

59 

32 

71 

15 

154 

20 

68 

44 

94 

17 

179 

25 

77 

59 

123 

24 

210 

30 

86 

78 

159 

32 

251 

35 

95 

103 

204 

42 

301 

40 

104 

134 

259 

55 

360 

45 

113 

172 

327 

71 

422 

50 

122 

220 

409 

92 

493 

55 

131 

279 

508 

117 

561 

60 

140 

350 

624 

149 

648 

65 

149 

437 

761 

187 

739 

SOLUBILITY  OF  GASES  IN  WATER  AT  ATMOSPHERIC  PRESSURE  AND  VARIOUS 

TEMPERATURES— (SIEBEL) 


1  Volume  Water  Dissolves  Volume 
Gases. 

32°  F. 

39.2  °  F. 

50.°  F. 

60°  F. 

70°  F. 

Air  

0.0247 

0.0224 

0.0195 

0.0179 

0.0171 

Ammonia  

1049.6 

941.9 

812.8 

727.2 

654.0 

Carbon  dioxide.  

1.7987 

1.5126 

1  .  1847 

1.0020 

0.9014 

Sulphur  dioxide  

79.789 

69.828 

56.647 

47.276 

39.374 

Marsh  gas  

0.0545 

0.0499 

0.0437 

0.0391 

0.0350 

Nitrogen  

0.0204 

0.0184 

0.0161 

0.0148 

0.0140 

Hydrogen  

0.0193 

0.0193 

0.0191 

0.0193 

0.0193 

Oxygen  

0.0411 

0.0372 

0.0325 

0.0299 

0.0284 

EXPLOSIVE  MIXTURES   (WYER) 


Combustible  Gas. 

Hydrogen 

Carbon  monoxide. 

Marsh  gas 

Olefiant  gas 

Acetylene 

Coal  gas 


Air. 
1 
1 
1 
1 
1 
1 


Gas. 
2.4 
2.4 
9.6 

14.4 

12. 
5.7 


CHAPTER   IX 
GAS    ANALYSIS 

The  Orsat  Apparatus. — This  is  very  generally  used  for  the  analysis  of  flue, 
exhaust  and  chimney  gases,  and  also  for  producer  gas,  and  may  be  considered  accurate 
within  limits  of  2%,  1%  being  a  practical  attainment  with  fairly  fresh  reagents. 

It  consists  of  three  double  pipettes  seen  in  the  accompanying  illustration  of  Orsat 's 
apparatus,  B,  C  and  D,  which  are  arranged  in  a  case  and  connected  by  means  of  a 


Qrsats  Apparatus. 

FIG.  106. — Forms  of  Orsat  Apparatus. 

capillary  tubing  to  a  measuring  burette  A,  which  is  enclosed  by  a  water  jacket. 
Each  pipette  is  closed  by  glass  stop-cocks,  represented  by  E,  P  and  G,  and  by  the 
glass  stop-cock  H,  which  furnishes  an  inlet  for  air  from  J. 

A  leveling  bottle  L  provides  a  means  for  transferring  the  gas;  connected  below 
by  glass  tubing  to  the  pipettes  B  C  and  D  are  three  others  of  similar  nature,  whose 
ends  S,  S'  and  S"  are  connected  to  a  flexible  rubber  bag  with  small  rubber  tubing. 

238 


GAS   ANALYSIS  239 

This  bag  acts  as  a  seal  and  prevents  the  reagents  in  the  pipette  from  absorbing  any 
oxygen  from  the  air. 

Usually  the  water  jacket  may  be  filled  with  ordinary  water,  the  function  of  which 
is  to  prevent  changes  in  the  volume  of  gas  due  to  temperature.  This  is  especially 
the  case  where  the  apparatus  is  so  situated  as  to  be  subject  to  sudden  changes  in 
temperature  or  to  drafts,  both  of  which  conditions  should  be  as  much  as  possible 
avoided,  but  where  such  are  extreme,  such  water  connection  should  be  made  with  the 
jacket  as  to  insure  a  water  circulation  and  secure  uniform  temperature. 

The  Fisher  modification  of  the  Orsat  apparatus  is  of  particular  convenience  for 
use  in  traveling. 

The  manipulation  of  these  various  apparatuses  are  identical.  The  level  bottle 
marked  L  is  filled  with  pure  and  preferably  distilled  water.  The  stop-cocks  E,  F  and 
G  are  closed,  and  the  cock  H  is  open.  The  measuring  burette  is  then  partly  filled 
by  raising  the  level  bottle  L  and  forcing  air  through  the  exit  J.  The  stop-cock  H  is 
then  closed  and  the  level  bottle  L  is  again  lowered,  the  air  remaining  in  the  burette 
and  capillary  tube  is  exhausted  to  such  an  extent  that  upon  opening  the  stop-cock 
E  the  reagent  in  pipette  B  will  be  drawn  up  to  a  point  just  below  the  connecting 
rubber  M,  The  stop-cock  E  is  then  closed  and  the  reagents  in  pipettes  C  and  D  are 
raised  to  corresponding  positions  in  a  similar  manner. 

When  this  has  been  accomplished  the  stop-cock  H  must  be  opened  and  the  level 
bottle  L  raised,  the  result  being  to  force  any  air  through  both  the  burette  A  and  all 
the  capillary  tubing,  displacing  same  by  the  water  which  should  overflow  for  an  instant 
from  the  end  of  the  capillary  at  the  point  /,  and  while  same  is  overflowing  stop-cock 
H  must  be  closed. 

Orsat  Analysis. — This  being  done,  the  apparatus  is  ready  for  making  an  analysis. 
Connection  is  made  with  the  gas  sample  tube  or  other  source  of  supply  at  the  end  J 
of  the  capillary  tubing.  The  precautions  to  be  taken  being  the  same  as  before,  that 
is,  the  gas  should  be  blowing  from  the  source  of  the  sample  to  some  extent  at  the 
moment  of  making  connection,  in  order  that  there  be  no  residual  air  in  the  connecting 
tubing. 

Draw  in  about  50  cc.  of  gas  (there  is  a  content  of  100  cc.  from  the  stop-cock  H 
on  the  capillary  tube  to  a  point  marked  100  cc.  near  the  bottom  of  the  jacketed  and 
graduated  burette,  the  graduations  being  in  tenths  of  cc.)  This  is  done  by  lowering 
the  level  bottle  L, 

Immediately  after  admitting  the  gas  the  stop-cock  H  is  closed.  The  level  bottle 
L  is  raised  and  lowered  to  cause  the  gas  to  come  in  complete  contact  and  effusion 
with  the  water  which  is  thus  saturated  with  the  absorbable  factors  of  the  gas. 

The  stop-cock  H  is  then  again  opened  and  the  gas  expelled,  so  as  to  completely 
fill  the  burette  and  capillary  with  the  saturated  water  and  upon  its  overflowing  at 
J,  the  stop-cock  H  is  again  closed. 

The  sample  for  analysis  is  now  taken,  being  drawn  in  through  the  tube  J,  as  before, 
to  the  amount  of  a  little  more  than  100  cc.,  say  1  or  2%.  Stop-cock  H  is  imme- 
diately closed  upon  securing  this  amount,  and  a  minute  or  so  should  elapse  to  permit 
the  walls  of  the  burette  to  drain,  after  which  the  pinch-cock  /  is  closed  on  the  rubber 
tubing,  which  connects  the  level  bottle  L  and  the  burette  which  is  close  to  it. 

By  raising  the  level  bottle  L  a  pressure  is  created,  which  is  of  course  due  to  the 


240  GAS   PRODUCERS 

height  of  the  water  column  formed,  so  that,  when  gradually  opening  the  pinch-cock 
/  the  gas  is  slowly  forced  into  the  burette. 

This  should  be  continued  until  the  lowest  point  of  the  meniscus  reaches  the  100 
cu.cm.  mark  on  the  burette  A,  when  the  pinch-cock  /  must  be  closed.  You  will  then 
have  100  cc.  of  gas  at  slightly  above  atmospheric  pressure.  By  opening  the  stop- 
cock H  for  an  instant,  this  excess  will  escape  to  the  air,  leaving  exactly  100  cc.  of 
gas  at  atmospheric  pressure. 

The  pinch-cock  7  is  then  opened  and  the  level  bottle  L  brought  to  a  position 
where  the  level  of  the  liquid  contained  equals  the  level  of  the  liquid  in  the  burette. 
It  will  be  found  that  this  level  in  the  burette  will  be  at  the  100  cc.  mark,  in- 
dicating the  amount  of  gas  contained  to  be  correct,  or  100  cc.  at  atmospheric 
pressure. 

C0<z,  — To  determine  carbon  dioxide,  we  use  the  first  absorbent,  usually  potassium 
hydroxide  (KOH),  which  is  contained  in  pipette  B;  opening  the  stop-cock  E,  the 
level  bottle  L  is  raised  and  the  reagent  forced  down  the  front  pipette  B  and  up  into 
the  rear  pipette,  laying  bare  the  contained  glass  tubes  which  are  wet  with  the  reagent 
and  thereby  exposing  a  great  absorbing  surface.  The  reagent  quickly  absorbs  the 
CC>2  which  is  present  in  the  gas.  One  passage  of  the  gas  through  the  pipette  is  usually 
sufficient.  Assuming  the  reagent  to  be  reasonably  fresh,  the  exposure  in  this  instance 
should  be  about  two  minutes. 

By  raising  and  lowering  the  level  bottle  L  several  times  all  the  gas  is  brought 
into  complete  contact  with  the  absorbent.  It  may  then  be  drawn  back  into  the 
burette  for  measurement  by  lowering  the  level  bottle  L,  the  stop-cock  E  then  being 
closed;  when  the  reagent  has  ascended  to  its  former  position  the  rubber  connection 
must  also  be  closed. 

The  period  of  a  minute  or  more  should  then  elapse  for  the  walls  of  the  burette  to 
drain;  the  level  of  the  liquid  in  the  level  bottle  L  and  the  level  in  the  burette  must 
then  be  brought  to  the  same  height  and  the  level  read  on  the  graduated  scale,  taking 
the  lowest  point  of  the  meniscus  on  the  scale,  the  difference  between  this  and  100 
giving  the  quantity  of  CO2  absorbed.  The  operation  can  then  be  again  repeated 
(the  stop-cock  E  being  closed  as  before),  after  waiting  one  minute  for  the  burette  to 
drain  the  measurement  is  again  taken  and  a  comparison  made  to  see  if  the  latter 
reading  corresponds  with  the  former.  This  is  to  assure  yourself  that  the  absorption 
has  been  complete.  The  reading  subtracted  from  100,  the  total  volume  of  the  gas 
'sample,  gives  the  percentage  of  C02. 

0. — With  regard  to  the  determination  of  oxygen,  the  residue  or  gas  remaining 
after  the  previous  absorption  is  passed  into  the  second  pipette  marked  C  which  should 
contain  an  alkaline  aqueous  solution  of  potassium  pyrogallate.  This  absorbs  the 
oxygen.  Previous  to  taking  the  final  measurement,  the  operation  should  be  repeated, 
as  before  stated,  to  make  sure  that  all  oxygen  is  absorbed.  The  period  of  contact 
between  the  gas  and  the  reagent  should  be  from  2  to  3  minutes  in  each  absorption, 
the  absorption  being  repeated  until  there  is  no  difference  in  the  reading.  One  minute 
must  of  course  be  allowed  previous  to  making  the  final  reading  for  the  draining  of 
the  walls  of  the  burette,  this  being  done  whenever  a  reading  is  made. 

The  reading  here  obtained,  when  subtracted  from  the  previous  reading,  gives  the 
percentage  of  oxygen  contained  in  the  sample. 


GAS    ANALYSIS 


241 


CO. — The  most  difficult  determination  is  that  of  the  carbon  monoxide,  which 
is  obtained  by  passing  the  residual  of  the  sample  into  the  third  pipette  marked  D.  A 
longer  time  should  be  allowed  for  absorbing  this  gas,  the  period  running  from  5  to  20 
minutes,  and  the  operation  is  repeated,  as  before  explained,  until  no  further  absorp- 
tion is  manifest.  The  final  reading  obtained,  subtracted  from  the  previous  one  (the 
potassium  pyrogallate  test)  gives  the  percentage  of  carbon  monoxide. 

.V. — To  find  the  nitrogen  content,  the  percentages  of  CO,  0,  and  C02,  may  be 
added  together  and  subtracted  from  the  total  100,  which  gives  the  percentage  of 
nitrogen  by  difference.  This  of  course  is  a  broad  and  inaccurate  assumption,  inas- 
much as  nearly  all  gases  contain  small  quantities  of  hydrogen  and  hydro- 
carbons. 

Precautions. — Care  should  be  taken  in  making  analyses  with  the  Orsat  apparatus, 
that  the  operations  are  performed  in  the  order  above  named.  Between  absorptions, 
either  in  the  same  or  different  burettes,  allow  an  interval  of  time  to  elapse  for  burettes 
and  capillaries  to  drain. 

The  glass  stop-cocks  may  be  kept  from  binding  by  the  use  of  a  little  glycerine 
or  a  mixture  of  1  part  tallow  and  3  parts  vaseline.  Considerable  care  should  be  taken 
in  noting  the  activity  of  the  reagents.  This  may  be  done  by  keeping  a  record  of  the 
length  of  time  of  exposure  and  the  result  of  absorption. 

Improved  Form. — A  pipette  has  been  designed  by  The  United  Gas  Improvement 
Co.  to  take  the  place  of  the  old  form  of  double-absorption  pipettes  in  general  use  among 
gas  analysts.  Although  two  pipettes  are  com- 
bined in  one,  the  whole  is  lighter  than  one  of 
the  old  form,  besides  taking  up  no  more  room. 
In  this  form  only  one  connecting  up  is  necessary, 
the  gas  being  passed  from  one  pipette  to  the 
other  by  a  simple  manipulation  of  the  stop-cock. 
Any  one  who  has  ever  tried  to  fill  one  of  the  old 
style  pipettes  will  appreciate  the  ease  of  filling. 
By  disconnecting  the  pipettes  they  may  be  filled 
without  difficulty  with  the  aid  of  a  funnel.  Also 
the  cost  of  the  single  pipette  is  much  less  than 
the  cost  of  two  of  the  old  style. 

Apparatus  for  making  quantitive  determi- 
nations of  the  Orsat  type,  are  necessarily  more 
or  less  inaccurate,  the  degree  of  which  being 
dependant  upon  (a)  activity  of  the  reagents, 
(b)  skill  of  the  operator,  (c)  condition  (including 
freedom  from  leakage)  of  the  apparatus. 

It  must  be  borne  in  mind  that  the  reagents 
used  in  the  absorption  of  0,  CO  and  C02 

have  a  strong  affinity  for  atmospheric  oxygen,  and  must  be  protected  from  the  air 
by  careful  corking  when  not  in  use. 

In  using  absorption  burettes  of  this  type  even  where  the  reagents  are  fresh,  to 
insure  thorough  absorption,  the  CO  should  be  exposed  to  the  action  of  the  reagents 
25  minutes,  the  C02  for  2  minutes,  and  the  0  for  4  minutes. 


FIG.  107.— The  U.  G.  I.  Form  of  Orsat 
Apparatus. 


242  GAS   PRODUCERS 

The  Morehead  Apparatus. — The  seven  constituents  which  compose  most  indus- 
trial gases,  and  which  are  ordinarily  analyzed  for,  are: 

Carbonic  dioxide C02 

Ethylene C2H4 

Oxygen 0 

Carbon  monoxide CO 

Hydrogen H 

Methane CH4 

Nitrogen N 

Of  these,  the  first  four  are  determined  by  absorption,  the  next  two  by  explosion 
and  the  last  by  difference. 

The  gas  analyzing  apparatus,  as  designated  by  Mr.  Morehead,  consists  of  a  gradu- 
ated burette  fitted  with  platinum  electrodes  and  a  storage  bulb.  Three  aspirator 
bottles  with  rubber  tubing  and  an  electric  sparking  outfit  are  also  required.  Both 
glass  pieces  are  fitted  with  three-way  cocks.  The  measuring,  explosion,  washing,  and 
the  entire  analysis  is  made  in  the  graduated  burette;  the  bulb  is  used  only  for  storage 
of  the  reserve  supply  of  gas  after  the  copper  absorption  in  case  the  explosion  is  unsatis- 
factory. All  measurements  of  the  gas  in  the  burette  must  be  made  with  the  surface 
of  the  water  in  the  bottle  A  and  that  of  the  water  in  the  burette  at  the  same  level, 
and  the  cock  3  set  to  connect  the  two.  This  insures  atmospheric  pressure  on  -the 
"gas  in  the  burette. 

In  preparing  the  apparatus  for  an  analysis,  first  fill  the  aspirator  bottles  A, 
B,  and  C  with  water,  then  open  No.  3  so  that  the  water  from  A  can  run  into  the 
burette  and  funnel,  and  be  careful  to  see  that  all  bubbles  of  air  are  out  of  the  rubber 
tubing,  then  open  No.  1  and  No.  2,  so  that  bulb  will  fill  with  water  from  B.  When 
these  are  full,  close  No.  1  and  No.  2.  The  three-way  cock  No.  3  at  the  base  of  the 
burette  is  fitted  with  a  long  stem  intended  to  dip  into  a  beaker  of  water  so  that  a 
water  seal  can  be  maintained  during  the  analysis.  When  the  apparatus  is  quite  full 
of  water,  open  the  cock  leading  to  the  hose  from  which  the  sample  is  to  be  taken, 
allow  the  gas  to  blow  through  the  hose  for  a  few  seconds  to  insure  the  expulsion  of  all 
air,  and  then  remove  the  funnel  and  attach  the  hose  to  the  outlet  at  No.  1  and  open 
No.  3  so  that  the  water  will  run  through  the  stem  of  the  cock  into  the  breaker.  As 
the  surface  of  the  water  lowers,  the  gas  will  follow.  After  the  water  is  all  expelled 
allow  the  gas  to  pass  through  the  stem  of  the  cock  and  bubble  through  the  seal.  When 
the  gas  has  passed  through  for  say  ten  seconds,  close  No.  1  and  turn  No.  3  so  that 
the  bottle  A  is  connected  with  burette.  Place  funnel  on  No.  1  and  fill  with  water. 
Then  open  No.  1  slowly  and  let  some  of  the  gas  bubble  through  the  water  in  the  funnel. 
Then  close  No.  1  and  take  the  bottle  A  in  the  hand  and  raise  and  lower  it  until  the 
surface  of  the  water  in  the  bottle  is  on  a  level  with  the  surface  of  the  water  in  the 
burette  and  both  at  the  100  cc.  mark.  When  there  is  just  100  cc.  in  the  burette 
the  analysis  may  be  started. 

Place  the  bottle  A  on  the  shelf,  turn  the  cock  No.  3  so  as  to  connect  the  burette 
with  the  beaker,  drain  the  funnel,  leaving  about  |-inch  of  water  in  the  bottom,  and 
put  in  the  funnel  about  20  cc.  of  potassium  hydrate  solution.  Be  sure  that  No.  3 


GAS   ANALYSIS 


243 


is  set  so  that  the  burette  is  connected  with  the  beaker.  Now  open  No.  1  and  let  the 
potassium  hydrate  drain  slowly  into  the  burette.  When  it  has  nearly  all  gone  through 
close  No.  1  and  open  No.  2  and  let  water  from  bottle  B  or  C  through  into  the  burette 
for  about  ten  seconds.  Rinse  the  funnel,  and  fill  it  with  water.  Then  close  No.  1 
and  No.  2,  turn  No.  3  so  that  the  burette  is  connected  with  bottle  A,  and  read  the 
contraction  of  the  gas  by  holding  the  bottle  A  with  the  surface  of  the  water  in  the 


FIG.  108. — The  Morehead  Gas  Burette  in  use. 

bottle  level  with  the  surface  of  the  water  in  the  burette.     The  amount  absorbed  as 
indicated  by  the  contraction  equals  the  carbon  dioxide. 

Replace  the  bottle  A  on  shelf,  turn  No.  3  to  connect  the  burette  with  the  beaker, 
and  with  the  pipette  put  about  two  drops  of  bromine  in  the  funnel  under  the  surface 
of  the  water.  Drain  this  slowly  into  the  burette  as  in  the  previous  operation  until 
the  burette  is  filled  with  brown  bromine  fumes,  then  admit  the  rest  of  the  bromine 
and  most  of  the  water  in  the  funnel.  Then  pour  into  the  funnel  about  30  cc.  of 
potassium  hydrate  solution  and  drain  part  of  this  solution  in  slowly  until  the  burette 


244  GAS   PRODUCERS 

and  the  surface  of  the  water  are  quite  free  from  bromine  fumes  and  until  the  surface 
of  the  water  ceases  to  rise.  Only  the  most  superficial,  if  any,  washing  at  all  with 
water  from  B  is  necessary  after  this  absorption.  Measure  as  explained  above.  The 
amount  absorbed  equals  the  illuminants. 

Next  add  about  one-half  of  a  small  spoonful  of  pyrogallic  acid  to  the  20  or  more 
cc.  of  hydrate  solution  left  in  the  funnel,  and  stir  with  a  glass  rod.  Drain  this  through, 
wash  the  burette  and  funnel  and  measure  in  the  way  previously  explained.  The 
resulting  contraction  equals  the  oxygen. 

Next  place  about  20  cc.  of  a  saturated  solution  of  copper  monochloride  in  strong 
hydrochloric  acid  in  the  funnel,  drain  through  wash,  and  measure.  The  amount 
absorbed  equals  the  carbon  monoxide.  This  reagent  should  be  added  rather  slowly 
and  several  minutes  allowed  for  its  action  on  the  CO.  The  carbon  monoxide  is  the 
last  constituent  to  be  determined  by  absorption.  Of  the  remaining  three,  two  must 
be  determined  by  an  explosion  and  the  third  by  difference. 

Turn  cock  No.  3  so  as  to  give  connection  between  bottle  and  burette.  Turn 
No.  1  and  No.  2  so  as  to  connect  A  through  burette  and  bulb  with  B.  Place  B  on 
the  table  and  A  on  the  shelf,  thus  causing  the  gas  to  enter  the  storage  bulb.  When 
all  but  exactly  10  cc.  has  passed  into  the  bulb  close  No.  1  and  No.  2.  Then  measure 
gas  as  usual,  first  passing  a  little  water  from  C  direct  into  the  burette  so  as  to  get  all 
of  the  gas  out  of  the  passages  between  the  bulb  and  the  burette.  By  manipulating 
A  have  the  amount  of  gas  in  the  burette  just  10  cc.  A  small  excess  may  be  gotten 
rid  of  through  No.  1  and  the  funnel.  Turn  No.  3  so  as  to  connect  burette  and  beaker, 
drain  funnel  and  open  No.  1  and  let  about  10  cc.  of  air  enter.  Then  close  No.  1, 
remove  funnel,  and  connect  oxygen  hose  to  inlet  No.  1.  Then  open  No.  1  and  let 
about  20  cc.  of  oxygen  enter.  Close  No.  1  and  measure  contents  of  burette  accurately. 
The  quantity  of  the  mixture  in  burette  should  be  about  40  cc.  Attach  wires  to  the 
electrodes  on  the  sides  of  the  burette,  turn  No.  3  so  that  burette  is  connected  to  the 
beaker  and  cause  a  spark  to  pass  between  the  electrodes.  Run  in  a  little  water  from 
C  to  cool  the  gas,  or  better,  if  provided  with  a  lead  covered  table,  run  some  water 
over  the  outside  of  the  burette  by  raising  the  funnel  a  little  way.  Measure  the  con- 
traction. This  contraction  is  known  as  the  "first  contraction."  Make  a  note  of  this, 
then  place  about  15  cc.  of  potassium  hydrate  solution  in  the  funnel  and  drain  into 
burette,  wash  and  measure.  This  contraction  is  known  as  the  "  second  contraction.'' 
The  amount  of  gas  left  after  the  absorption  for  CO  is  called  the  "  Constant." 

The  amount  of  hydrogen  in  the  original  mixture  is  equal  to  the  first  contraction 
multiplied  by  two,  minus  four  times  the  second  contraction,  the  result  divided  by 
three  and  multiplied  by  the  constant. 

(First  contraction)  X  2-4  (second  contraction) 

\olume  of  H=—  — ^ —  -  X     constant. 

o 

Vol.  of  CH4  =  Second  contraction X"  constant." 

The  difference  between  the  sum  of  all  the  percentages  found  and  100  is  the  per- 
centage of  nitrogen. 

Precautions. — Make  all  of  the  solutions  full  strength. 


GAS   ANALYSIS  245 

Do  not  mix  the  pyrogallic  acid  with  the  hydrate  solution  until  ready  for  use, 
as  the  potassium  pyrogallate  thus  formed  will  absorb  oxygen  from  the  air  and  lose 
its  strength.  A  couple  of  minutes  should  be  given  the  oxygen  absorption  with  pyro- 
gallate when  flue  gases  or  engine  exhaust  is  being  analyzed. 

Always  mix  the  copper  chloride  a  few  days  before  using,  and  keep  several  pieces 
of  clean  bare  copper  wire  in  the  bottle  with  the  solution.  It  grows  stronger  with 
standing.  When  it  turns  milky  in  the  burette  it  has  good  strength. 

The  apparatus  may  be  cleaned  from  time  to  time  by  running  in  a  solution  of 
potassium  bichromate  in  sulphuric  acid.  This  is  useful  when  the  platinum  points 
become  coated  with  carbon. 

Always  keep  clean  water  in  the  aspirator  bottles,  and  in  the  apparatus,  even 
when  standing  from  day  to  day,  as  this  allows  the  water  to  attain  the  temperature  of 
the  room,  and  it  also  prevents  the  cocks  from  getting  tight. 

The  surface  of  the  water  in  the  burette  will  be  curved  and  all  readings  are  taken 
by  observation  of  the  bottom  of  the  meniscus. 


FIG.  109.— Gas  Sample  Can. 

For  getting  samples  it  is  best  to  get  four  sample  cans.  In  getting  the  sample 
the  can  is  placed  in  an  upright  position  and  filled  quite  full  of  water  in  order 
to  expel  all  of  the  air.  A  tube  connected  with  the  upper  stop-cock  is  then  introduced 
into  the  space  from  which  the  gas  sample  is  to  be  drawn,  and  the  lower  stop-cock  is 
opened  allowing  the  water  to  run  out,  and  thus  the  sample  is  aspirated  into  the  can. 
In  drawing  samples  from  places  which  have  a  suction  instead  of  a  pressure,  such  as 
the  inlet  of  an  exhauster,  or  at  the  base  of  a  stack,  or  in  the  breeching  of  a  boiler,  the 
water  should  be  allowed  to  flow  out  through  a  U-shaped  glass  tube  attached  by  a 
piece  of  rubber  hose  to  the  lower  stop  cock.  If  this  is  not  done,  after  the  water  is 
all  out.  air  will  enter  and  spoil  the  sample.  It  is  essential  to  draw  out  all  of  the  water, 
even  if  only  a  small  sample  is  required,  as  a  number  of  the  constituents,  illuminants 
and  C02  for  example,  are  soluble  in  water.  To  get  the  sample  out  of  the  can  the 
lower  stop-cock  is  connected  by  a  hose  with  a  source  of  water  under  pressure  such  as  a 
hydrant,  and  as  the  water  runs  into  the  can  the  gas  will  be  displaced  and  may  be  led 
by  means  of  a  hose  to  the  burette. 

The  entire  apparatus  can  be  supported  by  clamps  from  one  standard  fastened 
to  or  placed  upon  the  table. 

By  keeping  the  apparatus  and  the  bottles  filled  with  water  and  the  reagent  bottles 
in  immediate  proximity,  they  acquire  about  the  temperature  of  the  room  and  of  the 
gas,  and  the  error  arising  from  the  source  of  temperature  changes  in  the  gas  is  negligible. 

The  explosions  take  place  in  the  measuring  burette.  A  coil  which  will  give  a 
^-inch  spark  is  ample.  Too  strong  a  spark  is  apt  to  crack  the  glass  as  is  a  continuous 
play  of  sparks  between  the  points,  or  a  play  of  sparks  when  the  burette  is  dry.  If  the 
explosion  does  not  occur  simultaneously  with  the  first  spark,  the  spark  need  not  be 
continued  as  something  else  is  wrong. 


246  GAS   PRODUCERS 

No  special  care  need  be  taken  in  measuring  the  amount  of  air,  or  of  oxygen  added 
for  the  hydrogen  determination.  Variations  of  these,  through  fairly  wide  limits,  are 
immaterial.  Care  must  be  taken,  however,  to  measure  accurately  the  amount  of 
gas  taken  for  the  explosion,  and  the  total  amount  of  the  gas,  air  and  oxygen  just  before 
the  explosion. 

The  bulb  D,  which  is  not  graduated,  is  used  to  hold  the  excess  of  gas  when  the 
explosion  is  being  made.  The  analyst  occasionally  loses  an  explosion,  and  if  it  were 
not  for  the  gas  held  in  this  bulb,  the  entire  analysis  would  have  to  be  made  over.  By 
putting  into  the  bulb  all  of  the  gas  which  is  left  after  the  copper  absorption  except 
the  10  cc.  which  is  used  for  the  explosion,  several  explosions  ma}'  be  made  as  checks 
on  each  other,  or  in  case  the  first  one  is  lost. 

The  principal  precaution  necessary  is  to  see  that  the  temperature  of  the  apparatus 
and  of  the  water  used,  and  of  any  additional  water  which  may  be  added,  as  well  as 
the  temperature  of  the  sample  undergoing  examination,  does  not  change  during  the 
analysis.  A  change  of  4.93°  F.  will  cause  a  change  of  1%  in  the  volume  of  any  gas. 
The  temperature  at  which  the  analysis  is  made  is  immaterial  if  it  only  remains  constant. 

If  the  apparatus  is  to  be  installed  for  constant  use,  it  is  well  to  fasten  the  standard 
to  a  laboratory  table  over  a  lead  covered  drain  to  a  sink;  then  the  excess  of  any 
reagent  in  the  funnel  which  is  not  used  may  be  disposed  of,  or  the  funnel  itself  may 
be  washed  by  raising  it  a  little  way,  and  pouring  in  water,  and  allowing  the  water 
or  the  excess  of  the  reagent  to  run  down  the  outside  of  the  burette  on  to  the  lead 
cover  of  the  table.  This,  however,  does  not  apply  to  any  excess  of  bromine  which 
must  run  through  the  burette  into  the  beaker  and  not  be  liberated  in  the  air  of  the 
laboratory.  It  is  wrell  to  wash  the  glass  tube  or  pipette  used  in  handling  the  bromine 
before  laying  it  down. 

Care  should  be  taken  in  handling  bromine.  Keep  it  always  under  water,  and 
do  not  allow  it  to  come  in  contact  with  the  skin.  Bromine  is  an  exceedingly  energetic 
reagent  and  will  cause  painful  chemical  burns.  If  bromine  fumes  are  breathed,  relief 
can  be  obtained  from  the  irritation  caused  to  the  throat  by  inhaling  steam.  The 
slick  feeling  caused  by  getting  potassium  hydrate  on  the  hands  may  be  removed  by 
a  little  dilute  hydrochloric  acid. 

Just  before  the  readings  are  taken  it  is  well  to  admit  to  the  burette  a  little  water 
from  B  in  order  to  expel  what  gas  may  be  held  in  the  glass  tubing. 

The  absorption  of  illuminants  by  bromine  is  a  heat-producing  reaction,  and  the 
increased  temperature  is  apt  to  cause  the  sample  to  expand  unduly  and  may  cause 
the  loss  of  a  part  of  the  same,  and  thus  vitiate  the  analysis.  If  it  is  seen  that  the 
expansion  is  becoming  excessive  a  little  water  may  be  added  from  B.  The  bulb  at 
the  bottom  of  the  burette  is  provided  for  this  contingency,  however.  In  the  analysis 
of  acetylene,  which  contains  over  90%  of  illuminants,  this  is  especially  apt  to  occur. 
If  the  percentage  of  illuminants  is  high,  it  may  be  well  to  admit  a  little  water  from  B 
to  restore  the  normal  temperature  to  the  gas  after  the  absorption  with  bromine. 

Air  is  added  to  the  mixture  to  be  exploded  merely  to  lessen  the  jar.  If  the  gas 
is  very  poor,  or  contains  large  quantities  of  nitrogen,  no  air  need  be  added.  Oxygen 
is  added  to  insure  combustion. 

The  same  hydrate  solution  is  used  for  the  absorption  of  C02,  of  bromine  fumes, 
of  C02  after  methane  and  with  the  pyrogallic  acid  for  oxygen.  This  should  be  about 


GAS   ANALYSIS  247 

one  part  by  weight  of  KOH  to  two  parts  of  water.  1  c.c.  of  this  will  absorb  about 
44  cc.  of  C02  though  it  is  well  to  use  a  large  excess.  Use  only  commercially  pure 
chemicals. 

In  acetylene,  flue  gas,  engine  exhaust,  air  arid  gasoline  gas  there  is  no  hydrogen 
or  methane,  and  hence  the  analysis  need  not  be  carried  beyond  the  absorption  with 
copper  for  CO,  and  the  oxygen  tank  or  apparatus,  the  electric  coil,  batteries,  etc., 
need  not  be  purchased.  In  these  analyses  the  sum  of  the  first  four  contractions 
subtracted  from  100  gives  the  percentage  of  nitrogen. 

Never  allow  the  funnel  to  become  quite  cmp:y,  always  keep  about  J-inch  of  water 
or  other  liquid  in  the  bottom  to  prevent  the  suction  of  air  into  the  burette. 

If  the  cocks  stick,  they  can  usually  be  loosened  by  a  little  hot  water  on  the  outside. 
They  should  be  kept  well  lubricated  with  a  mixture  of  one  part  of  vaseline  to  1J  parts 
paraffine. 

Where  many  analyses  are  to  be  made,  or  where  dispatch  is  an  important  element, 
it  will  be  more  satisfactory  to  obtain  a  cylinder  of  compressed  oxygen  for  use  in  the 
hydrogen  and  methane  determinations,  but  where  the  apparatus  is  to  be  moved  from 
place  to  place,  or  is  to  be  used  only  occasionally,  or  where  the  analyses  are  confined 
for  the  most  part  to  gases  which  do  not  contain  hydrogen  or  methane,  such  as  flue 
gases,  acetylene,  air,  engine  exhaust,  etc.,  a  cheaper  and  quite  satisfactory  substitute 
can  be  had  in  a  small  retort  by  means  of  which  the  oxygen  can  be  generated  on  the 
spot  as  needed. 

To  generate  oxygen  this  retort  is  filled  not  more  than  one-half  full  with  a  pulver- 
ized thoroughly  mixed  charge  of  potassium  chlorate  and  manganese  dioxide  in  the 
proportions  of  20  of  the  first  to  1  of  the  latter  by  weight.  This  is  heated  gently  over 
a  Bunsen  lamp.  The  evolution  of  oxygen  begins  at  once  and  it  may  be  led  to  the 
burette  by  means  of  a  rubber  tube.  As  100  gms.  of  potassium  chlorate  will  produce 
27,000  cc.  of  oxygen,  and  only  about  20  cc.  of  oxygen  are  used  for  one  analysis,  a  very 
small  spoonful  of  the  mixture  will  suffice  for  a  great  many  explosions. 

The  portable  form  of  Morehead's  apparatus  for  the  analysis  of  gases  not  containing 
hydrogen  or  methane  is  intended  chiefly  for  the  use  of  engineers  for  determining  the 
quality  of  flue  gases  as  an  indicator  of  the  efficiency  of  the  fuel  used  and  the  manner 
in  which  it  is  applied  to  the  fires  for  the  economical  production  of  heat  for  steam 
boilers  or  other  purposes,  or  it  may  be  used  for  the  determination  of  all  other  gases 
whose  combined  volume  does  not  exceed  50%  of  the  original  sample,  except  hydrogen 
and  methane.  It  consists  of  a  modified  form  of  Morehead's  gas  burette,  enclosed  in 
a  wooden  carrying  case  of  convenient  form,  measuring  2  ft.  long,  8^  ins.  wide  by  4  ins. 
deep  with  a  handle  on  the  side,  and  is  fitted  with  a  metal  eyelet  at  the  top  by  which 
to  suspend  it  when  in  use.  No  table  or  support  other  than  a  nail  in  the  wall  is  needed 
for  the  convenient  operation  of  this  outfit.  When  properly  suspended  the  top  of  the 
box  containing  the  outfit  is  used  as  the  upper  shelf  for  the  leveling  bottle,  the  bottom 
end  of  the  box  being  the  lo\ver  shelf  or  table  for  the  support  of  the  beaker  which  forms 
the  seal  at  the  lower  end  of  the  burette.  In  the  same  case  with  the  burette  are  bottles 
containing  the  necessary  reagents  and  also  the  beaker  and  leveling  bottle,  each  in  a 
compartment  of  its  own.  The  entire  outfit,  including  chemicals,  etc.,  weighs  11£  Ibs. 

The  syphon  jet  here  illustrated  shows  a  method  of  using  the  Orsat  or  similar 
apparatus  in  conjunction  with  a  suction  pump.  The  analytical  apparatus  may  be 


248 


GAS   PRODUCERS 


connected  to  or  in  series  with  the  pipe  line  between  the  gas  main  and  the  jet.  The 
latter  method  is  preferable  for  the  introduction  of  niters  for  the  determination  of 
solid  impurity  or  moisture.  With  this  arrangement  the  gas  meter  must  also  be  inter- 
posed. 

Checking  Results. — Dr.  J.  M.  Morehead,  Chief  Chemist  to  the  People's  Gas  Light 
Plant  of  Chicago,  in  discussing  the  possibility  of  checking  the  analysis  of  the  gas 
determination  of  an  Orsat  or  similar  apparatus,  stated  as  follows: 

There  is  a  sort  of  a  check  which  in  a  rough  sort  of  a  way  may  be  used  to  check 
the  accuracy  of  a  flue  gas  analysis,  but  I  do  not  know  of  any  formula  which  would  be 
accurate.  I  have  had  a  search  made  of  the  literature  on  this  subject  and  have  been 
unable  to  locate  such  a  formula.  I  do  not  see  how  any  formula  could  be  accurate. 


!  PINCH  COCK 


FIG.  110. — Suction  Pump  for  Gas  Sampling. 

In  regard  to  a  check  formula  for  flue  gas,  the  air  contains  practically  21%  by 
volume  of  oxygen  and  when  this  oxygen  combines  with  carbon  to  form  CO2,  it  pro- 
duces its  own  volume  of  carbon  dioxide.  Hence  if  carbon  is  burned  to  CO2  with  the 
oxygen  from  the  air,  the  oxygen  which  combines  with  the  carbon  produces  an  equal 
volume  of  CO2  to  replace  the  oxygen  combined  and  removed,  and  hence  the  sum  of  the 
oxygen  and  the  CO2  must  equal  21%  of  the  volume  of  the  products  of  combustion, 
provided  the  combustion  is  complete,  i.e.,  if  no  CO  is  produced. 

When  oxygen  combines  with  carbon  to  form  CO  it  makes  twice  its  volume  of  gas, 
hence  if  pure  carbon  was  partially  burned  in  air  and  produced  both  CO2  and  CO,  then 
the  formula  CO2  +  iCO  +  O  =  21,  would  be  correct  and  might  be  used  as  a  check  on 
the  accuracy  of  the  analysis,  where  coke  or  hard  coal  is  used  as  a  fuel. 

The  use  of  such  a  formula,  however,  as  a  check  on  a  flue  gas  or  engine  exhaust 
analysis  where  the  fuel  contained  any  proportion  of  either  free  or  combined  hydrogen 
would  not  answer,  as  the  hydrogen  in  the  fuel  combines  with  the  oxygen  in  the  air 
of  the  draft  to  form  water,  and  as  this  moisture  would  not  appear  in  the  analysis  some 
of  the  oxygen  will  not  be  accounted  for,  and  the  percentage  of  nitrogen  which  would 
go  to  make  up  the  100%  would  seem  unduly  high  and  might  indicate  poor  boiler 
economy  when  such  might  really  not  be  the  case.  You  can  see  that,  theoretically, 


GAS   ANALYSIS  249 

just  the  proper  amount  of  hydrogen  burned  in  air  would  form  water  with  all  of  the 
oxygen  and  give  a  flue  gas  or  engine  exhaust  analysis  showing  100%  free  nitrogen. 

When  soft  coal,  oil,  gas,  or  in  fact  any  fuel  excepting  pure  carbon,  is  burned  with 
air  the  hydrogen,  either  free  or  combined,  combines  with  a  portion  of  the  oxygen  and 
this  oxygen  does  not  appear  in  the  analysis  at  all,  and  its  place  is  taken  by  nitrogen. 
The  excess  of  nitrogen  over  the  79%  which  air  contains  is  roughly  in  proportion  to 
the  amount  of  hydrogen,  either  free  or  combined,  which  the  fuel  contains.  This 
applies  to  all  the  hydrocarbons,  and,  though  in  a  much  less  degree  to  the  carbo- 
hydrates such  as  wood,  which,  while  they  do  contain  hydrogen,  also  contain  oxygen 
in  the  form  of  water. 

Incidentally  this  fact  destroys  the  accuracy  of  the  tables  made  by  people  trying  to 
sell  continuous  flue  gas  analysis  apparatus,  in  which  they  say  that  the  deficit  of  CC>2 
below  21%  shows  poor  combustion  in  the  boiler. 

Tests  for  Impurities  in  Gas. — Ammonia. — If  red  litmus  paper  is  moistened 
and  held  over  a  gas  jet  of  unlighted  gas  and  the  color  of  the  litmus  changes  from  red 
to  blue  the  gas  contains  ammonia. 

If  yellow  turmeric  paper,  slightly  moistened  with  water  and  held  over  a  jet 
of  unlighted  gas,  turns  to  a  brown  color,  ammonia  is  in  the  gas. 

Carbonic  Acid. — Impregnate  water  with  the  gas  and  add  a  few  drops  of  sulphuric 
acid;  if  minute  bubbles  of  carbonic  acid  gas  are  readily  disengaged,  there  is  CC>2 
in  the  gas.  Or,  pass  it  through  a  solution  of  barium  chloride;  •  if  the  gas  contains 
carbonic  acid,  carbonate  of  barytes  will  be  precipitated;  or,  pass  the  gas  through 
clear  lime-water,  and  carbonate  of  lime  will  be  precipitated. 

Sulphureted  hydrogen. — Saturate  a  piece  of  writing  paper  with  a  solution  in 
distilled  water  of  acetate  of  lead  or  nitrate  of  silver  and  hold  over  a  jet  of  unlighted 
gas.  Pure  gas  will  produce  no  discoloration;  if  a  brown  stain  is  given,  the  lime  in  the 
purifiers  should  be  renewed  as  the  gas  contains  H2S. 

Bisulphide  of  carbon. — The  presence  of  this  impurity  can  only  be  detected  by 
means  of  special  apparatus,  of  which  there  are  several  types. 

Atmospheric  air  test. — Collect  a  portion  of  the  gas  over  mercury  and  pass  up  a  few 
drops  of  caustic  potash,  and  afterwards  a  drop  or  two  of  a  solution  of  pyrogallic  acid. 
If  the  liquor  assumes  a  blood  red  hue,  oxygen,  indicating  the  presence  of  atmospheric 
air,  is  mixed  with  the  gas. 

CARBON   DIOXIDE   DETERMINATION 

To  the  experienced  gas  producer  operator  the  gas  content  in  CO2  tells  the  story 
of  the  entire  producer  operation,  indicating  low  heats,  thickness  of  fire  bed,  irregularity 
of  draft,  porosity  of  fire,  air  leaks,  or  other  irregularity.  A  compact  and  remarkably 
convenient  burette  has  been  designed  by  G.  M.  S.  Tait  for  the  determination  of  CO2 
and  its  operation  is  extremely  simple. 

Tait  C0;>  Burette. — The  illustration  herewith  shows  a  new  type  of  simplified  Orsat 
apparatus  especially  designed  for  the  analysis  of  gas  containing  carbon  dioxide,  and, 
as  shown  in  the  illustration  herewith,  is  equipped  with  only  one  pipette  for  the 
testing  of  that  element.  The  operation  of  this  apparatus  is  extremely  simple  and  is 
as  follows: 


250 


GAS   PRODUCERS 


The  water  bottle  (11)  is  filled  with  water  in  the  usual  manner  and  by  raising  same 

the  water  flows  over  into  measuring  burette  (8) 
until  same  is  filled. 

In  the  meanwhile  inlet  (1)  has  been  con- 
nected with  a  rubber  tubing  to  the  source  of 
the  gas  supply,  while  outlet  (2),  also  a  rubber 
tubing,  is  closed  by  means  of  some  form  of 
pinch-cock. 

Now  by  lowering  bottle  (11)  the  water  in 
burette  (8)  will  flow  out  producing  a  suction  in 
pipe  (1)  which  will  draw  gas  into  measuring 
burette  (8),  which  should  be  done  until  gas 
reaches  the  zero  mark  on  the  scale  of  the 
burette. 

The  pinch-cock  on  inlet  (1)  should  then  be 
closed  and  the  three-way  glass  cock  (3)  should 
then  be  turned  in  position  shown  in  illustra- 
tion. 

Then  by  raising  water  bottle  (11)  so  as  to 
cause  water  to  flow  back  into  burette  (8)  the 
gas  contained  therein  will  then  be  forced  down 
through  capillary  tubing  (6)  and  be  caused  to 
bubble  up  through  the  absorbent  contained  in 
chamber  -(7)  until  all  the  gas  has  been  drawn 
off  in  this  way  and  is  contained  in  pipette  (6). 
By  again  lowering  the  water  bottle  (11)  and 
reversing  the  position  of  glass  cock  (3),  the 
gas,  minus  the  carbon  dioxide  which  has  been 
absorbed,  will  then  pass  off  through  outlet  (4) 
and  back  into  burette  (8),  giving  a  direct  reading 
of  the  percentage  of  carbon  dioxide  which  has 
been  absorbed. 

In  use  this  apparatus  is  found  to  be  very 
quick  acting,  the  average  time  necessary  for 
analyzing  the  flue  gas  or  producer  gas  being 
two  minutes. 

The  extreme  simplicity  of  this  apparatus 
and  the  fact  that  its  use  can  be  learned 
by  any  one  in  a  few  minutes,  makes  it  a 
particularly  useful  piece  of  apparatus  for  all 
those  interested  in  combustion,  whether  in 
the  form  of  gas  producers  or  fires  under 
steam  boilers. 

The  percentage  of  CC>2  in  producer  gas 
FIG.  lll.-TaitC02  Burette.  ig  &  valuable  indicator  of  the  working  and 

condition  of  the  fuel  bed.      It    has    therefore    seemed    advisable   to   give   at   some 


GAS   ANALYSIS 


251 


length  descriptions  of  some  of  the  apparatus  used  for  the  purpose  of  giving  con- 
tinuous indications  during  operation. 

Uehling  Gas-Composimeter. — The  action  of  the  gas-composimeter  is  based  on 
the  law  governing  the  flow  of  gas  through  two  small  apertures.  This  law  may  be 
illustrated  by  a  simple  diagram  representing  two  chambers  C  and  C'  which  are  in 
communication  with  each  other  through  the  aperture  B,  and  with  the  source  of 
gas  through  the  aperture  A.  C"  is  connected  with  an  aspirator  D  as  shown.  The 
monometers  p  and  q  indicate  the  gas  tension  within  the  respective  chambers. 

The  aspirator  set  in  action,  a  vacuum  is  created  in  chamber  C',  the  gas  will  flow 
from  the  chamber  C  through  aperture  B  to  chamber  C',  creating  a  vacuum  in  C  which 
will  cause  gas  to  enter  through  aperture  A,  thus  establishing  a  continuous  flow  of  gas 
through  both  apertures. 

If  a  constant  vacuum  of  say  48  ins.  be  maintained  in  chamber  C'  and  the  two 
apertures  A  and  B  are  of  the  same  size  and  are  maintained  at  the  same  temperature, 


Si! 


FIG.  112. — Principle  of  the  Gas-Composimeter. 

the  monometer  p  will  show  about  one-half  the  vacuum  maintained  in  C',  due  to  the 
fact  that  the  apertures  oppose  equal  resistance  to  the  passage  of  the  gas.  This  relation 
will  be  maintained  so  long  as  the  same  volume  of  gas  flows  through  B  that  enters  at  A. 

If,  however,  a  constituent  of  gas  be  continuously  taken  away  or  absorbed  from 
the  gas  in  passing  through  chamber  C  the  vacuum  therein  will  be  correspondingly 
increased.  This  increase  of  vacuum  in  C,  shown  by  the  manometer  p  therefore  correctly 
indicates  the  volume  of  gas  absorbed  and  in  the  gas-composimeter  is  utilized  to  indicate 
the  percentage  of  the  constituent  of  the  gas  to  be  determined. 

To  embody  the  principle  described  into  a  practical  apparatus,  the  following  con- 
ditions must  be  fulfilled: 

I.  The  gas  must  be  brought  to  the  instrument  under  a  constant  tension  and 
must  be  drawn  through  the  apertures  with  a  continuous  and  uniform  suction. 

II.  Both  apertures  must  be  located  in  a  medium  of  constant  temperature. 

III.  Provision  must  be  made  that  the  apertures  remain  perfectly  clean. 

IV.  The  chamber  C  must  be  made  perfectly  tight  so  that  no  gas  can  enter,  except 
through  the  aperture   A. 

V.  The  constituent  to  be  measured  must  be  completely  absorbed  after  the  gas 
passes  through  A  and  before  it  passes  through  B. 


252 


GAS   PRODUCERS 


Condition  I. — The  regulator  consists  of  a  cylinder  H,  8  ins.  in  diameter  and  5  ft. 
high,  filled  with  water,  as  shown,  into  which  project  the  tubes  aa',  bb'  and  cc'.  The 
tube  aa'  is  open  to  the  atmosphere  at  a  and  extends  to  within  a  few  inches  of  the 
bottom  of  H.  The  end  of  the  tube  bb'  is  exactly  48  ins.  above  the  lower  end  of  aa' 


FIG.  113. — Diagram  of  the  Uehling  Gas-Composimeter. 

and  the  lower  end  of  cc'  is  just  6  ins.  above  the  lower  end  of  aa'.  The  cylinder  is  filled 
with  water  so  that  the  tube  W  is  submerged  several  inches.  The  gas  inlet  J  which 
connects  with  the  source  of  gas  communicates  with  aperture  A  through  D,  f,  k,  F,  g, 
and  also  communicates  with  the  regulator  H  by  means  of  a  pipe  cc'  which  joins  pipe 
/  and  k  at  12. 


GAS   ANALYSIS  253 

If  valve  1  is  opened,  the  aspirator  E  is  started,  suction  is  created  through  the 
pipe  w>n '  in  the  chamber  C"  above  the  water,  which  suction  increases  until  the  pressure 
of  the  atmosphere  overcomes  the  pressure  of  the  water  column  in  the  tube  aa'  when 
air  bubbles  through  the  water  into  C" '.  The  air  thus  entering  satisfies  the  aspirator 
and  prevents  any  further  increase  in  suction,  and  neutralizes  irregularities  due  to 
change  in  steam  pressure,  etc. 

It  is  evident,  that  so  long  as  the  suction  is  sufficient  to  draw  air  through  aa',  the 
horizontal  plane  of  water  xx'  in  which  the  plane  aa'  terminates  is  under  atmospheric 
pressure.  The  plane  ?///'  lying  48  ins.  above  xx'  is  under  a  sucticn  of  48  ins.  and  the 
plane  zz'  being  6  ins.  above  xx'  is  under  a  suction  of  6  ins.  of  water.  Therefore  the 
contents  of  tube  W  corresponding  to  chamber  C  in  the  first  figure  must  be 
under  a  constant  sucticn  of  48  ins.  of  water,  similarly  the  contents  of  tube  fee'. 
from  which  the  gas  flows  to  aperture  A,  is  under  a  constant  suction  of  6  ins.  of 
water. 

Aperture  e  at  upper  end  of  filter  D  is  so  gauged  that  more  gas  will  pass  through  it 
than  can  pass  through  aperture  A  and  still  not  be  sufficient  in  quanitty  to  destroy 
the  48-in.  suction  in  tube  W.  The  excess  escapes  at  c'  and  bubbles  up  through  the 
water  into  C"  from  where  it  is  drawn  off  together  with  the  air  entering  at  aa'  and  the 
gas  from  which  the  CC>2  has  been  absorbed  entering  at  b'. 

This  arrangement  fulfils  condition  I  so  long  as  the  water  level  in  H  is  not  allowed 
to  fall  below  the  plane  yy'.  When  this  occurs  the  water  must  be  replenished  from 
jar  I  by  opening  cock  6. 

Condition  II  is  fulfilled  by  placing  both  apertures  A  and  B  in  a  chamber  X  which 
is  kept  at  a  uniform  temperature  of  212°  by  the  exhaust  steam  of  the  aspirator  Er 
which  is  permitted  to  escape  at  atmospheric  pressure  through  the  pipe  ww. 

Condition  III  is  fulfilled  by  placing  a  large  filter,  not  shown,  at  the  source  of  the 
gas  supply,  together  with  cotton  filters  D  and  the  small  filters  F  and  Ff  before  each 
aperture  by  which  the  gas  is  perfectly  cleaned  and  the  apertures  protected  from  being 
fouled. 

Condition  IV.— Chamber  C  is  composed  of  all  the  tube  connections  and  chambers, 
between  apertures  A  and  B.  All  these  connections  consist  of  drawn  copper  tubing, 
all  the  joints  of  which  are  accurately  made  and  carefully  tested  so  that  no  leak  can 
occur,  which  fulfills  this  condition. 

Condition  V. — To  remove  the  element  to  be  determined  from  the  gas  drawn 
through  the  apertures,  with  certainty,  a  continuous  supply  of  an  efficient  absorbent 
flowing  in  the  opposite  direction  and  exposing  an  abundant  surface  must  be  supplied. 
For  this  purpose,  the  absorption  tube  N  is  provided. 

Chamber  C  of  the  first  diagram  is  in  the  second  composed  of  the  pipe  g' ',  absorb- 
tion  chamber  N,  the  pipe/",  filter  F',  pipe/'"  and  pipe  i  branching  off  at  13.  To  the 
latter  is  connected  the  manometer  tube  //,  the  recording  gauge  P  through  the  pipe  h' 
and  the  observation  gauge  G  through  pipe  h.  The  manometer  tube  //  and  gauge  G 
are  so  calibrated  that  the  suction  between  aperture  A  and  B  can  be  read  off  in  per  cent, 
of  CO2  contained  in  the  gas. 

The  tube  h  connecting  gauge  G  may  be  extended  so  that  the  gauge  can  be  placed 
at  a  point  most  convenient  for  the  fireman  or  attendant  for  whose  guidance  it  is  to 
serve. 


254  GAS    PRODUCERS 

The  water  in  manometer  tube  vv  shows  the  height  of  water  in  the  regulator  H 
above  the  line  xx'  and  must  be  kept  above  the  index  r', 

The  water  level  in  glass  s  shows  the  6-in.  suction,  and  the  water  levels  in  the  U 
tube  M  show  the  resistance  in  the  line  plus  the  chimney  draft. 

Operation. — Opening  valve  1  starts  the  aspirator  E,  a  vacuum  is  created  in 
chamber  C" ,  which  causes  the  flow  of  gas  through  the  system.  An  excess  of  gas 
enters  through  /  D  and  aperture  e  into  /,  and  the  quantity  not  required  for  analysis 
escapes  through  ccr  into  C"  direct.  A  continuous  sample  flows  from  /  through  k  to 
F  from  F  into  g  where,  surrounded  by  the  exhaust  steam  from  the  aspirator  E,  it  is 
heated  to  212°,  thence  passes  through  aperture  A  and  through  g'g'  into  the  absorption 
tube  N,  where  the  constituent  to  be  determined  is  absorbed  by  a  suitable  reagent. 
From  the  absorption  tube  the  remaining  gas  flows  through  /"  and  F'  into  /'"  where 
it  is  again  heated  to  21 2°,  thence  passes  through  aperture  B  and  by  way  of  bb'  into 
chamber  C"  from  where  it  is  continuously  removed  by  the  aspirator  together  with 
all  other  gases  entering  the  chamber.  The  absorption  tube  N  is  filled  with  quartz 
pebbles.  For  the  continuous  analysis  of  gas  for  CO2  the  surfaces  of  these  pebbles 
are  kept  moist  by  continuously  dropping  a  dilute  solution  of  caustic  soda  or  potash 
upon  them,  which  flows  from  the  tank  T  through  the  pipe  p.  The  flow  is  regulated  by 
the  cock  3  and  can  be  observed  through  the  sight  feed  at  14. 

The  absorbing  solution  flows  from  N  through  oo'  into  the  receiving  tank  T'. 
Pipe  d  is  simply  to  guard  against  the  possibility  of  any  absorbent  reaching  filter  F'. 
When  T  is  nearly  empty  the  solution  is  lifted  back  by  closing  the  cocks  3  and  8  and 
opening  valve  2,  thus  creating  a  vacuum  in  T  by  means  of  the  aspirator  E".  This 
operation  is  repeated  each  time  T  is  empty,  until  the  solution  has  become  saturated, 
after  which  a  fresh  solution  must  be  "supplied.  When  solution  in  tank  T'  has  been 
lifted  to  T  cock  8  should  again  be  opened. 

The  gas-composimeter  is  continuous  in  its  operation,  the  water  column  in//  and 
that  in  observation  gauge  G  varies  in  height  in  front  of  a  scale  graduated  to  show  the 
percentage  of  CO2  contained  in  the  gas  passing  through  the  instrument  and  the  record- 
ing gauge  makes  a  continuous  autographic  record  of  same. 

Sarco  Recorder. — The  recorder  is  suspended  on  a  wall,  preferably  in  the  immediate 
vicinity  of  the  boiler  or  furnace,  to  which  it  is  attached,  so  that  the  furnaceman  may 
have  it  in  continuous  view,  and  be  enabled  to  turn  to  account  immediately  the  informa- 
tion which  the  machine  provides.  It  may,  however,  also  be  placed  any  distance 
away  from  the  producers,  in  an  office  or  other  convenient  situation,  as  may  be  desir- 
able, without  any  detriment  to  the  results  obtained. 

A  f-in.  pipe,  which  taps  the  gas  chamber  of  producer  or  furnace,  is  connected  to 
the  inlet  pipe  D  of  the  instrument,  and  the  gas  is  drawn  through  the  machine  by  a 
special  aspirator  Q,  fixed  to  the  top  of  the  instrument  by  means  of  standard  T.  Thus 
a  continuous,  rapid  passage  of  the  gas  is  secured,  which,  in  average  cases,  renders  it 
possible  to  read  on  the  chart  the  effect  of  an  alteration  in  the  firing  within  a  few 
minutes  of  its  occurrence. 

The  power  required  to  procure  and  deal  with  the  gas  samples  is  derived  from  a 
fine  stream  of  water  at  a  head  of  about  2  to  3  ft.  Any  ordinary  clean  water  may  be 
used;  only  6  to  8  gallons  are  required  per  hour  (according  to  the  speed  at  which  the 
machine  is  operated),  and  the  water  may  be  used  again  after  passing  through  the  recorder. 


GAS    ANALYSIS 


255 


After  actuating  ejector  Q,  a  portion  of  the  water  flows  to  the  small  tank  L,  which 
serves  as  a  pressure  regulator,  and  is  provided  with  an  overflow  tube  R.  From  this 
tank  the  water  enters  tube  H  in  a  fine  stream,  the  strength  of  which  is  adjusted  by 
the  cock  S  (according  to  the  number  of  records  that  may  be  desired  per  hour),  and 
gradually  fills  the  vessel  K,  which  consists  of  an  upper  and  a  lower  compartment,  the 
two  being  in  communication  with  one  another 
through  a  tube  erected  in  the  upper  chamber 
and  reaching  nearly  to  the  top  of  same. 

The  water,  which  enters  this  vessel  K 
through  the  tube  H,  gradually  fills  the 
upper  chamber  and  thus  compresses  the  air 
contained  in  it.  This  pressure  is  trans- 
mitted to  the  lower  compartment  through 
the  communication  tube  above  mentioned, 
and  here  acts  upon  the  mixture  of  glycerine 
and  water  (1  part  of  the  former  to  3  of  the 
latter)  with  which  this  is  filled,  driving  it 
cut  into  the  calibrated  tube  C. 

While  this  has  been  taking  place,  the 
aspirator  Q  has  been  drawing  a  continuous 
stream  of  gas  through  D,  C,  and  E,  in  the 
direction  indicated  by  the  arrows.  When 
the  rising  liquid  in  C  has  reached  the  inlet 
and  outlet  to  this  vessel,  no  further  gas 
can  enter  the  calibrated  tubes  for  the  mo- 
ment, and  the  aspirator  will  now  draw  the 
gas  through  the  seal  F,  and  out  in  the 
direction  of  the  arrow  for  the  time 
being. 

Before  the  liquid  can  close  the  center 
tube  in  C,  the  gas  has  to  overcome  the 
slight  resistance  offered  by  the  elastic  bag 
P,  and  is  thereby  forced  to  assume  atmos- 
pheric pressure.  The  moment  the  liquid 
has  scaled  the  lower  open  end  of  this  center 
tube, '  exactly  100  cc.  of  flue  gas  are 

trapped   off    in    the    outer   vessel    C   and   its'    companion    tube,   under  atmospheric 
pressure. 

As  the  liquid  rises  further,  the  gas  is  forced  through  the  thin  tube  Z  and  into 
vessel  A,  which  is  filled  with  a  solution  of  caustic  potash  (KOH)  of  1.27  specific  gravity. 
Upon  coming  into  contact  with  the  surface  of  the  potash  and  the  moistened  sides  of 
the  vessel,  the  gas  is  freed  from  any  carbon  dioxide  that  may  be  contained  in  the  sample, 
this  being  rapidly  and  completely  absorbed  by  the  potash. 

The  remaining  gas  gradually  displaces  the  potash  solution  in  A,  sending  it  up 
into  vessel  B.  This  has  an  outer  jacket,  filled  with  glycerine  and  supporting  a  float 
A".  Through  the  center  of  this  float  reaches  a  thin  tube,  through  which  the  air  in  B 


FIG.  114. — The  Sarco  Automatic  CO2 
Recorder. 


250 


GAS   PRODUCERS 


is  kept  at  atmospheric  pressure.     The  float  is  suspended  from  the  pen  gear  M  by  a 

silk  cord   and   counterbalanced  by 
the  weights  X. 

The  rising  liquid  in  B  first 
forces  a  portion  of  the  air  therein 
out  through  the  center  tube  in 
the  float,  and  then  raises  the  latter. 
This  causes  the  pen  lever  to  swing 
upwards,  carrying  pen  Y  with  it. 

The  mechanism  is  so  cali- 
brated and  adjusted  that  the  pen 
will  travel  right  to  the  top,  or 
zero  line,  on  the  chart  when  only 
atmospheric  air  is  passing  through 
the  machine,  and  nothing  is  ab- 
sorbed by  the  potash  in  A. 

Thus,  should  any  carbon  di- 
oxide be  contained  in  the  gas 
sample,  it  would  be  absorbed  by 
the  potash  in  A,  not  so  much  of 
this  liquid  would  be  forced  up  into 
vessel  B  and  the  float  would  not 
cause  the  pen  to  travel  up  so  high 
on  the  chart,  in  exact  accordance 
to  the  amount  of  CC>2  absorbed. 

The  tops  of  the  vertical  lines 
recorded  on  the  chart,  therefore, 
provide  a  continuous  curve  showing 
the  percentage  of  CO2  contained 
in  the  exit  gases  from  the  flues, 
on  a  permanent  diagram  arranged 
for  24  hours. 

When  the  liquid  in  C  has 
reached  the  mark  on  the  narrow 
neck  of  that  tube,  the  wiiole  of  the 
100  cc.  have  been  forced  on  to 
the  surface  of  the  potash,  one 
analysis  being  thus  complete.  At 
this  moment  the  power  water, 
which,  simultaneously  with  rising 
in  tube  H,  has  also  traveled  up- 
wards in  syphon  G,  will  have 
reached  the  top  of  this  syphon, 
FIG.  115. — Section  of  the  Sarco  CO2  Recorder.  which  then  commences  to  flow. 

Through     syphon    G   a    much 
larger  quantity  of  water  is  disposed   of  than   flows   in  through  cock  S,  so  that  the 


GAS   ANALYSIS  257 

power  vessel  K  is  rapidly  emptied  again.  The  moment  the  pressure  on  this  vessel 
is  released,  the  liquid  from  C  returns  into  the  lower  compartment,  and  float  N  to  its 
original  position. 

As  soon  as  the  liquid  in  C  has  fallen  below  the  gas  inlets  and  outlets  to  this  vessel, 
the  whole  of  the  remaining  gas  is  rapidly  sucked  out  through  E  by  the  powerful 
ejector  Q. 

It  will  be  seen  that  the  gas,  when  analyzed,  leaves  the  recorder  by  a  set  of  tubes 
entirely  separate  from  those  through  which  the  samples  are  obtained,  so  that  there  is 
no  possibility  of  mixing  the  old  with  the  new. 

The  important  problem  of  purification  of  the  gas  has  been  met  by  the  introduction 
of  a  specially  large  filter  of  greatly  improved  design.  One  of  these  is  supplied  with 
each  recorder.  The  vessel  F  is  provided  with  a  small  center  tube,  open  to  atmos- 
phere, and  this  serves  as  an  indication  that  the  pipe  line  is  clear,  the  ejector  drawing 
air  through  the  seal  in  the  case  of  stoppage. 

This  recorder  is  provided  with  a  permanent  and  automatic  check  as  to  its  correct 
adjustment  and  working.  The  instrument,  once  erected,  works  entirely  automatically 
and  requires  no  attention  beyond  changing  of  the  chart  and  winding  of  the  clock 
every  24  hours,  and  renewal  of  the  potash  solution  every  fortnight. 

The  Wise  CO^  Indicator. — The  following  description  of  an  invention  by  W.  L. 
Wise,  was  the  subject  of  a  communication  from  the  Jones-Julia  Manufacturing 
Company  of  New  York: 

This  device  relates  to  apparatus  for  analyzing  continuous  stream  of  gas  for  the 
purpose  of  ascertaining  the  percentage  of  a  constituent  thereof.  It  has  been  proposed 
heretofore,  the  patentees  point  out,  to  ascertain  the  percentage  of  constituent  by 
feeding  the  gas  continuously  in  limited  amount  through  an  absorbent,  and  determin- 
ing the  value  of  such  constituent  by  the  change  of  tension  produced  by  the  removal 
of  such  constituent  by  the  absorbent  as  indicated  upon  a  suitable  manometer.  But 
this  method  is  said  to  be  open  to  the  objection  that  a  change  in  the  pressure  or  tension 
at  which  the  gas  is  fed  to  the  instrument  will  cause  a  fluctuation  in  the  tension  of  the 
gas  in  the  space  with  which  the  manometer  is  connected,  and  will  therefore  affect  the 
reading  of  the  instrument;  and  hence  with  this  method  the  results  will  be  only  accurate 
for  a  given  pressure  for  which  the  apparatus  has  been  adjusted,  and  which  has  been 
kept  stationary.  The  accuracy  of  the  reading  will  likewise,  for  a  similar  reason,  be 
affected  by  changes  at  the  vacuum  or  suction  end  of  the  system. 

The  object  of  the  apparatus  is  to  overcome  this  objection  by  feeding  the  gas  in 
two  streams,  absorbing  an  absorbable  constituent  thereof  from  one  of  the  streams 
passing  in  limited  amount  through  the  absorbent  and  then  through  a  chamber  in 
which  the  tension  may  be  observed,  and  utilizing  the  difference  between  the  changed 
tension  or  pressure  thus  produced  and  the  tension  or  pressure  of  the  other  stream  as 
an  indication  of  the  percentage  of  such  constituent.  The  limited  flow  of  gas  in  the 
chamber  or  chambers  whose  difference  of  pressure  is  measured,  is  preferably  secured 
by  connecting  them  with  the  pressure  and  exhaust  pipes  through  minute  inlets  and 
outlets.  A  manometer  is  connected  to  the  two  streams,  so  as  to  give  readings  which 
measure  the  distance  of  tension  or  pressure  between  them  due  to  the  removal  of  a 
constituent  of  the  gas  in  one  of  the  streams  by  the  action  of  the  absorbent.  To 
balance  the  resistance  of  the  passage  of  the  gas  through  the  absorbent  for  one  of  tb.3 


258 


GAS   PRODUCERS 


streams,  it  is  preferable  to  employ  a  non-absorbing  solution  in  the  path  of  the  other 
streams;  and  to  secure  a  reading  due  to  the  difference  of  tension  in  the  streams  of 
gas,  the  two  sides  of  the  manometer  may  be  connected  respectively  to  the  chambers 
or  spaces  through  which  the  streams  of  gas  flow  in  limited  amounts.  Under  this 
condition,  the  manometer  will  respond  properly  to  differences  of  tension  between 
the  two  streams;  but  it  will  be  affected  alike  on  its  two  sides  by  any  changes  in  the 
difference  of  tension  between  the  inlet  or  supply  and  the  exhaust  or  suction  ends  of 
the  streams  respectively.  The  readings  will  thus  not  be  disturbed. 

In  the  illustration,  B  is  the  supply  end  of  the  system  through  which  the  gas  (say, 
flue  gas)  is  fed  after  passing  any  necessary  filter  or  condenser.  A  is  the  suction  or 
exhaust  end  of  the  system;  the  flow  of  gas  being  due  to  the  difference  in  tension  or 
pressure  between  B  and  A.  At  I  the  gas  divides  into  two  streams,  one  of  which 
passes  through  a  minute  inlet  2  (comprising,  preferably,  a  tube  of  very  small  bore), 


FIG.  110. — Wise  Continuous  CO,  Indicator. 

and  escapes  through  a  similar  outlet  3  to  the  suction  end  A  of  the  system.  The 
other  stream  passes  in  a  similar  manner  through  a  minute  inlet  or  outlet  2'  and  3'. 
In  this  way  a  limited  amount  of  gas  only  can  pass,  and  a  certain  amount  of  vacuum 
will  be  produced  in  the  chambers  or  passages  located  between  2  and  3  and  between 
2'  and  3'.  Between  2'  and  3'  is  the  absorption  chamber,  comprising,  for  instance,  a 
tank  D  containing  a  solution  of  caustic  potash  or  other  absorbent. 

At  4'  (or  at  any  other  suitable  point  where  the  tension  of  the  gas  feeding  from 
B  is  changed  from  the  normal,  owing  to  the  absorption  of  the  constituent  carbon 
dioxide  or  other  gas),  a  pipe  is  led  to  one  side  of  a  manometer  F.  At  4,  in  the  pipe 
or  passage  between  2  and  3,  connection  is  made  to  the  other  side  E  of  the  manometer. 

Preferably,  there  is  interposed  in  the  connection  from  2  to  3  another  tank  C  con- 
taining a  non-absorbing  solution  through  which  the  gas  is  caused  to  pass,  so  that, 
by  regulating  the  depth  of  an  immersion  of  the  tubes  5  and  6,  the  resistance  to  the 
passage  of  the  gas  in  the  two  chambers  may  be  adjusted  to  produce  a  tension  which 
would  be  the  same  if  the  gas  were  of  such  a  nature  as  not  to  be  absorbed  or  modified 
in  respect  to  its  constituents  by  passing  through  either  tank  D  or  C.  Owing  to  the 


GAS   ANALYSIS  259 

system  of  connections,  it  is  obvious  that  the  changes  of  tension  at  4  and  4'  will  be 
the  same  if  caused  by  any  changes  or  difference  of  tension  between  B  and  A. 

If,  now,  gas  containing  carbon  dioxide  be  passed  through  the  apparatus,  it  will 
be  absorbed  in  the  potash  solution  in  D,  the  equilibrium  in  the  manometer  will  be 
disturbed,  and  the  liquid  in  the  measuring  tube  of  the  manometer  connected  to  F 
will  rise  in  direct  proportion  to  the  amount  of  gas  removed  by  the  solution  in  D.  This 
reading  enables  the  operator  to  ascertain  the  percentage  of  carbon  dioxide  as  usual. 
The  manometer  shown  has  a  sloping  or  inclined  graduated  tube  on  the  side  F  of  very 
small  internal  diameter,  which,  in  practice,  may  be  3  mm.  At  the  other  end  E,  a 
large  tube  or  bottle  is  employed;  so  that  practically  all  the  movement  due  to  changes 
of  pressure  will  be  in  the  small  tube.  If  the  capillary  attraction  in  the  small  tube 
causes  its  surface  to  stand  at  right  angles  to  the  bore  of  the  tube,  instead  of  occupying 
a  horizontal  plane,  the  apparatus  may  be  arranged  to  indicate  1%  for  each  one- 
fiftieth  of  an  inch  of  vertical  rise,  by  inclining  the  small  tube  at  such  an  angle  that 
this  movement  is  multiplied  by  10.  Thus,  if  the  tube  rises  1  in  10,  the  liquid,  in 
rising  one-fiftieth,  will  move  one-fifth  inch  in  the  bore  of  the  tube  for  each  1%. 

To  bring  the  apparatus  to  scale  or  to  register  correctly,  means  are  provided  for 
regulating  the  suction  applied  at  -4.  A  device  suitable  for  this  purpose  comprises  a 
liquid  containing  tank  G,  connected  to  the  suction  pipe  A,  and  having  a  regulable 
gas  inlet  tube  7,  which  immersion  may  be  altered  to  vary  the  rate  of  inflow  of  air  or 
gas  into  the  pipe  A  at  or  near  where  it  is  attached  to  the  outlets  3  and  3'.  By  depressing 
the  tube  7,  the  suction  or  vacuum  in  A  can  be  made  stronger;  while  by  raising  it  the 
vacuum  will  be  decreased,  owing  to  the  admission  of  air  or  gas  through  G.  A  manometer 
H  filled  with  glycerine  may  be  used  to  indicate  the  degree  of  suction  or  vacuum. 


CHAPTER   X 
GAS     POWER 

Development. — In  discussing  the  evolution  of  gas  power,  F.  E.  Junge  (Power, 
January,  1906,  p.  37),  in  a  paper  red  before  the  Am.  Soc.  Mech.  Eng..  said  that  for  ideal 
continuous  combustion  it  is  necessary  that  air  and  fuel  should  be  introduced  into 
gas  engines  in  correct  proportions  under  similar  cyclic  conditions  during  the  entire 
range  of  load.  Further,  the  two  constituents  must  be  perfectly  mixed  when  entering 
the  cylinder;  and,  since  combustion  causes  a  rise  of  internal  pressure  while  the  initial 
piston  stroke  tends  toward  its  reduction,  the  rapidity  of  heat  influx  must  bear  a  certain 
fixed  relation  to  the  piston  speed  in  order  that  the  two  counteracting  influences  may  be 
equalized,  and  continuous  combustion  at  constant  pressure  secured. 

In  the  Diesel  engine  none  of  the  foregoing  conditions  are  realized.  We  have  a 
constant  body  of  air  to  support  combustion,  a  pressure  of  injected  oil  vapor  which 
does  not  bear  a  fixed  relation  to  the  varying  internal  pressure,  and  therefore  a  speed 
of  fuel  influx  which  is  irregular  and  in  no  way  corresponds  to  the  piston  speed  of  that 
period.  Nor  does  each  fuel  molecule  on  entering  the  cylider  find  at  once  its  corre- 
sponding quantity  of  oxygen. 

The  Weidmann  engine  is  similar  to  the  Diesel  in  that  gasified  fuel  is  injected 
into  a  highly  compressed  body  of  air  in  the  working  cylinder,  with  the  remarkable 
difference,  however,  that  a  corresponding  amount  of  air  is  introduced  with  the  fuel 
by  a  receiver  piston  corresponding  to  the  speed  of  the  working  piston.  The  fuel  and 
air  are  so  intimately  mixed  that  combustion  must  occur  regularly. 

Although  engines  of  the  Otto  type  have  been  developed  to  a  remarkable  state 
of  perfection,  they  have  one  fundamental  weakness,  namely,  the  impossibility  of 
controlling  the  combustion.  The  irregularity  and  imperfect  mixing  of  the  charge, 
the  possibility  of  premature  ignition  and  after-burnings,  are  drawbacks  of  the  present 
working  cycle  of  gas  engines. 

Various  attempts  to  improve  the  efficiency  of  gas  engines,  such  as  prolonged 
expansion,  compounding  and  water  injection,  have  proved  to  be  entries  on  the  wrong 
side  of  the  balance  sheet.  The  drawbacks  common  to  all  these  so-called  improvements 
are  increased  bulk,  weight,  first  cost,  and  negative  work  expended.  The  combustion 
process  pure  and  simple,  as  used  in  the  standard  types  of  engines,  gives  the  highest 
economic  efficiency  attainable  in  the  Otto  cycle. 

Regarding  the  latest  thermal  performances  of  internal  combustion  engines,  atten- 
tion is  called  to  a  14-h.p.  Marienfelder  alcohol  motor  and  a  70-h.p.  Diesel  oil  engine, 
each  showing  an  indicated  thermal  efficiency  of  41.7%;  a  20-h.p.  Giildner  engine 

260 


GAS   POWER  261 

running  on  city  gas  with  42.7%  efficiency;  and  a  500-h.p.  Borsig-Oechelhaueser  coke 
oven  gas  engine  with  38.6%  efficiency,  all  running  under  full  load  conditions.  The 
operating  efficiency  is,  therefore,  between  32%  and  33%. 

Quality  of  Gas. — It  is  hardly  necessary  to  recite  the  economic  conditions  in  the 
industrial  world  which  are  urging  forward  the  development  of  a  more  efficient  and 
less  wasteful  system  for  the  development  of  heat  and  its  correlate  power.  Generally 
speaking,  however,  these  may  be  divided  under  two  heads,  viz: 

I.  The   conversion   into   useful  work  of   a  greater  proportion  of  heat  latent 

in  the  fuel  consumed. 

II.  The  utilization   of   diversified    and    inferior  fuels  for  the  production  of 

the  said  heat. 

In  the  first  consideration  we  find  a  possible  saving  of,  not  only  a  fuel  per  se  and 
its  first  cost,  but  the  attendant  conditions  involved  of  transportation,  labor  of  hand- 
ling, amount  of  reserve  stock,  and  the  capital  investment  required  to  maintain  such 
stock.  It  will  be  evident  that  an  increased  fuel  efficiency  of  one-third  would  decrease 
by  one-third  the  labor  and  transportation  involved  (frequently  a  large  portion  of 
the  total  expense),  and  decrease  the  necessary  storage,  together  with  the  captial  tied 
up  in  same,  by  an  equal  ratio,  showing  a  saving  in  both  actual  cash,  inexpediency 
(which  may  be  of  equal  import  under  conditions  of  inadequate  transportation  facili- 
ties), labor  stringency,  or  limited  space. 

Taking  the  second  consideration,  modern  practice  shows  that  any  fuel  is  appli- 
cable to  producer  work  which  contains  above  20%  of  combustible  matter.  The  yearly 
inroads  that  we  are  making  into  the  world's  limited  supply  of  high  class  coal  makes  it 
all  the  more  necessary  to  utilize  the  enormous  supply  of  inferior  coal,  lignite  and 
peat.  Lignite  will  average  perhaps  9400  B.T.U.  (2400  calories)  per  pound,  or  about 
3.3  Ibs.  per  b.h.p.  hour,  although  results  have  been  known  in  test  as  high  as  1.19  Ibs. 
per  h.p.  hour  (Meissen). 

Briefly,  the  author  will  outline  what,  in  his  estimation,  should  constitute  an 
ideal  gas  power  system. 

1.  The  plant  should  be  susceptible  of  complete  and  immediate  control. 

2.  The  plant  should  embrace  a  wide  range  of  capacity. 

3.  The  plant  should  possess  the  maximum  of  durability. 

4.  The  cost  of  the  plant  and  its  installation  should  not  be  prohibitive. 
Covering  the  first  point,  from  the  producer  standpoint  the  quality  of  the  gas  should 

be  as  nearly  as  possible  consent  and  the  constituents  of  the  gas  as  nearly  as  possible  of 
uniform  quantity  or  proportion.  This  matter  of  uniform  heat  value  cannot  be  too 
.strongly  emphasized. 

Upon  the  initial  and  constant  quality  of  the  gas  generated,  all  subsequent  calcu- 
lations and  regulations  must  depend  and  a  constant  quality  of  gas  must  be  assumed 
as  a  primary  condition  or  premise. 

Of  course,  under  working  conditions,  this  is  not  attainable,  the  output  being 
modified  by  such  conditions  as — 

1.  The  state  of  the  fire. 

2.  The  time  after  coaling. 

3.  Nature  of  fuel,  amount  of  output  or  demand,  etc. 


262  GAS   PRODUCERS 

Its  quality  should,  however,  be  kept  as  near  a  fixed  standard  as  lies  in  human 
power,  and  to  overcome  these  minor  irregularities  where  possible  a  small  storage  tank 
is  to  be  recommended.  The  connections  of  the  holder  are  the  reverse  of  those  in 
ordinary  practice. 

No  general  laws  can  be  laid  down  for  the  manufacture  of  a  specific  gas,  it  being 
necessary  in  each  individual  instance  to  obtain  a  routine  of  practice  experimentally, 
as  the  result  of  operation  with  a  particular  fuel  under  exact  conditions  in  each  appa- 
ratus and  load  factor.  When  it  is  found  that  a  certain  gas  gives  the  highest  efficiency 
and  the  most  satisfactory  results  the  conditions  of  operations  are  noted  and  a  system 
of  manipulation  may  be  evolved  for  daily  practice. 

Pre-ignitioji  Due  to  Hydrogen. — It  may  be  found  that,  as  a  result  of  certain  pro- 
portions of  steam,  blast  and  fuel,  the  resultant  gas  causes  pre-ignition.  This  (so  say 
the  best  authorities)  has  been  erroniously  attributed  heretofore  to  too  much  free 
hydrogen  in  the  gas. 

In  reality  this  is  not  the  case,  nor  has  it  been  found  possible  to  definitely  deter- 
mine exactly  what  this  is  to  be  attributed  to;  but  it  is  most  probably  caused  by  the 
ratio  of  free  hydrogen  to  some  other  component,  such  as  marsh  gas  or  other  carbon 
compound,  rather  than  to  the  actual  quantity  of  free  hydrogen  itself. 

Certain  it  is  that  whatever  may  be  the  origin  of  this  difficulty,  a  series  of  obser- 
vations upon  cause  and  effect  can  be  established,  and,  by  process  of  elimination,  a  more 
or  less  fixed  system  or  method  of  operation  may  be  determined. 

It  is  at  least  certain  that  the  action  of  hydrogen  in  the  cylinder  very  nearly 
approximates  hydrogen  in  its  properties  of  flame  propagation.  Its  initial  pressure 
is  sudden,  flamboyant,  and  intense,  dropping  off  after  a  severe  peak.  It  is  the  belief 
of  the  author  (in  which  he  may  be  wrong)  that  the  action  of  hydrogen  is  somewhat 
governed  or  tempered  by  the  flame  temperature  resulting  from  the  other  constituents 
of  the  gas. 

The  flame  propagation  of  hydrogen  is  so  rapid,  and  the  heat  generated  so  intense, 
as  to  make  it  practically  valueless  as  a  dynamic  or  engine  gas.  The  result  of  its  com- 
bustion is  static  rather  than  potential,  the  energy  generated  going  off  in  the  form  of 
radiant  heat  rather  than  of  power  due,  as  for  example  with  the  slower  expansion  and 
combustion  of  carbon  monoxide.  A  direct  example  of  this  wre  find  in  the  calorific 
efficiency  of  various  producer  gases,  where  we  find  that  while  the  efficiency  curve  is 
almost  vertical  up  to  a  thermal  value  of  104  B.T.U. ;  after  this  point  the  curve 
debouches  at  an  angle  closely  approximating  90°.  This  is  due  to  the  fact  that  this 
critical  point  represents  the  maximum  content  (in  commercial  practice)  of  CO  in 
producer,  and  that  with  other  so-called  producer  gas  of  nominally  higher  calorific 
value  the  increment  is  represented  by  hydrogen. 

The  matter  of  the  hydrogen  content  in  gas  is  considered  much  less  vital  a  matter 
now  than  formerly,  due  perhaps  to  such  experiments  as  those  of  Dr.  Charles  Lucke,  which 
go  to  show  that  the  point  of  ignition  of  hydrogen  in  gas,  due  to  heat  of  compression, 
is  approximately  the  same  as  that  of  CO. 

There  can  be  no  doubt,  however,  of  the  easy  ignition  of  the  hydrogen  in  gas  and 
the  high  velocity  of  the  flame  propagation,  whether  this  ignition  comes  from  burning 
refuse  in  the  cylinder  or  any  other  igniting  source.  A  decrease  in  the  annoyance  due 
to  the  presence  of  hydrogen  and  a  tendency  toward  "  prematures  "  appears  to  come 


GAS   POWER  263 

with  improved  engine  designs  involving  the  proper  calculation  of  cylinder  thickness, 
the  better  distribution  of  water  jacketing,  the  cooling  of  valves,  etc.,  until  a  point 
has  been  reached,  as  for  instance,  in  the  case  of  the  Riverside  engine,  where  a  gas  of 
from  30  to  40%  of  hydrogen  is  used  without  showing  any  tendency  to  premature 
ignition. 

It  will  be  found  that  gas  with  considerable  hydrogen  content  is  especially  difficult, 
if  not  impossible,  to  use  in  engines  which  do  not  thoroughly  and  rapidly  purge  or 
which  have  any  tendency  to  "  pocket  "  or  trap  products  of  combustion.  This  is  also 
true  where,  through  faulty  designs,  engine  cylinders  are  inclined  to  show  "  hot  spots  " 
or  to  possess  other  inequalities  of  temperature. 

The  author  has  known  of  gas  containing  17  to  18%  of  hydrogen  operating  with 
perfect  satisfaction,  while  the  production  of  hydrogen  being  reduced  to  14  or  15%, 
pre-ignition  occurred.  This  in  spite  of  the  popular  belief  that  pre-ignition  varies 
directly  with  the  amount  of  the  hydrogen  content. 

In  the  present  condition  of  the  science,  the  author  is  predisposed  to  a  low  thermal 
value,  slow  burning  gas,  as  furnishing  fewer  of  these  exigencies  to  cope  with,  and  a 
more  even  mean  effective  pressure.  It  is  very  possible  that  there  are  other  conditions 
in  this  connection  with  which  we  are  unacquainted  and  which  are  thus  far  unob- 
served. 

At  the  present  stage  of  our  knowledge  on  this  subject,  we  must  content  ourselves 
with  avoiding  conditions  known  to  produce  trouble,  in  which  connection  the  writer 
would  discourage  the  use  in  gas  engines  of  a  producer  gas  under  135  B.T.U.  value, 
with  a  content  of  over  12%  hydrogen,  where  the  compression  exceeds  100  to  125  Ibs. 
Even  this  amount  of  hydrogen  has  been  known  to  give  trouble  through  premature 
ignitions. 

Aqueous  Vapor. — Another  reason  which  may  be  inserted  here  for  retaining  the 
content  of  hydrogen  at  a  minimum  in  industrial  processes,  is  the  fact  that  in  all  metal- 
lurgical operations  where  there  is  a  combustion  reaction  of  H  to  H2O,  this  aqueous 
vapor  in  contact  with  any  metal  in  a  state  of  reduction  has  a  powerful  oxidizing  effect, 
which,  though  less  than  that  of  oil,  entails  considerable  loss  through  oxidation.  Again, 
in  any  operation  of  a  calcining  nature,  this  same  vapor  has  a  strong  catalytic  effect, 
extremely  detrimental  to  the  product. 

Another  property  of  aqueous  vapor  is  the  fact  that  its  specific  heat,  better  termed 
its  coefficient  of  heat  absorption,  since  it  varies  at  different  temperatures,  has  never 
been  exactly  determined  at  high  temperatures.  In  addition  to  the  966  B.T.U.  which 
it  contains  as  latent  heat,  it  carries  a  larger  portion  of  sensible  heat  than  is  usually 
realized  among  the  products  of  combustion. 

It  may  be  observed  in  this  connection  that  where  hydrogen  in  large  proportion 
occurs  in  producer  gas  of  very  low  calorific  value,  that  the  resultant  products  of  the 
hydrogen  combustion,  namely  H2O,  appears  in  the  form  of  aqueous  vapor  of  low 
tension,  almost  approximating  that  of  saturated  steam.  On  the  other  hand,  where 
the  combustion  of  hydrogen  takes  place  in  the  presence  of  other  hydro-carbon  com- 
pounds of  high  heat  value,  such  as  CH4  and  C2H4  and  C-iHe,  the  resultant  temperature 
or  heat  liberated  has  a  tendency  to  superheat  and  attenuate  this  vapor  to  a  very  high 
degree. 

It  is  undoubtedly  a  fact  that  the  saturated,  or  heavier  aqueous  vapor,  acts  as  a 


264  GAS   PRODUCERS 

retardent  of  combustion,  forming  a  damper  or  veil  over  the  ignition  point,  and  fre- 
quently creating  back-firing  through  a  "  hang-fire  "  on  the  part  of  a  portion  of  the 
gas  on  the  ignition  stroke. 

Gas  Power  Development. — It  will  be  found  that,  in  spite  of  the  most  careful  manip- 
ulation, theoretical  or  test  conditions  can  not  be  obtained  in  daily  or  commercial 
practice  by  perhaps  50%.  It  is  fortunate,  therefore,  that  the  large  margin  offered 
by  gas  engines  over  other  prime  movers  still  permits  a  chance  for  considerable  saving 
where  not  counterbalanced  by  the  original  installation  or  first  cost  of  the  plant.  It 
is  unfortunate  that  under  present  conditions  in  America  this  frequently  exceeds  that 
of  a  steam  plant  by  as  high  as  50%,  but  it  is  probable  that  this  state  of  affairs  is  but 
temporary,  the  cost  at  which  gas  power  plants  are  being  installed  abroad  going  to 
show  that  a  large  portion  of  cost  is  due  to  promoting  expense  rather  than  to  the  intrinsic 
cost  of  the  material  and  manufacture.  Already  the  price  line  of  gas  plants  is  reaching 
a  more  rational  basis,  and  obtaining  a  close  parity  to  its  steam  competitor. 

In  this  connection  it  must  be  remembered  in  all  comparisons  involving  gas  power, 
that  its  development  scarcely  covers  a  period  of  ten  years,  placing  it  practically  in  its 
infancy.  Only  recently,  in  fact,  has  gas  power  been  successful  in  the  production  of 
alternating  currents,  and  driving  in  parallel.  In  this  case  it  may  be  said  that 
where  such  work  is  proposed,  there  should  be  invariably  a  collaboration  between  the 
gas  engineer  and  the  electrician,  and  their  specifications  should  be  made  to  coincide 
by  a  third  engineer  familiar  with  both  branches  of  the  work.  As  an  extra  precaution, 
"  anti-hunting  "  devices  should  be  specified,  and  it  will  be  found  that  induction 
apparatus  will  work  more  satisfactorily  than  synchronous. 

The  spread  of  gas  power  for  this  class  of  service  is  becoming  daily  more  rapid, 
there  being  units  as  large  as  6000  kilowatts  in  operation.  Altogether,  there  is  in  the 
United  States  to-day  some  260,000  gas-driven  horsepower,  largely  used  for  the  genera- 
tion of  electricity,  but  when  it  is  considered  that  this  only  constitutes  3.3%  of  the 
two  million  available  horsepower,  the  enormous  field  for  the  spread  of  this  industry 
may  be  comprehended. 

A  great  advance  has  been  made  along  the  line  of  engine  regulation  by  the  aboli- 
tion of  the  "  hit-or-miss  "  type  and  the  substitution  of  the  throttling  or  admission 
regulation  system  of  governing  the  combustible  constituents. 

Operation  Conditions. — It  is  evident  that  each  atom  of  gas  must  meet  and 
properly  combine  with  its  proper  valence  of  oxygen.  Upon  the  thoroughness  of  this 
union  depends  efficiency;  upon  the  volume  depends  power.  It  will  be  observed, 
therefore,  as  a  fundamental  principle  of  combustion,  that 

1.  The  value  of  the  gas  (quantitative  analysis)  must  be  constant; 

2.  The  ratio  of  air  to  any  given  quantity  of  gas  of  fixed  value  must  be  constantly 
maintained; 

3.  The  volume  of  combined  ingredients  must  vary  with  the  load. 

Although  this  is  the  goal  to  which  all  effort  must  be  directed,  it  is  impossible,  at 
present,  of  absolute  attainment,  due  to,  for  instance,  the  variations  caused  in  the 
operation  of  the  producer,  such  as  the  condition  of  fuel  bed,  coaling  and  cleaning 
periods,  nature  of  fuel,  condition  of  heats,  etc.  In  this  connection  much  stress  should 
be  laid  on  the  care  and  character  of  the  management,  as  upon  this  factor  almost 
entirely  depends  the  economical  and  satisfactory  operation  of  the  plant. 


GAS   POWER  265 

The  conditions  aforesaid  are  especially  difficult  of  attainment  in  the  case  of  the 
direct-connected  suction  producer  (without  holder),  the  analysis  of  the  gases  of  which 
are  particularly  varying,  due  to  such  influences  as  the  variation  of  the  blast  by  reason 
of  changing  load  factors,  and  the  resultant  changes  in  both  temperatures  and  the 
products  of  combustion. 

In  order  to  obtain  greater  equalization  in  the  quality  of  the  gas  produced,  the 
writer  urges  where  praticable  the  use  of  a  storage  holder  and  exhauster,  even  if  of  a 
small  size,  as  it  tends  in  a  marked  degree  to  regulate  and  distribute  those  inequalities 
in  production  caused  by  coaling,  cleaning,  irregular  heats,  etc.  Its  use  as  a  possible 
agent  of  over-load  capacity  is  problematical,  producers  themselves  as  a  rule  being 
so  much  more  elastic  than  the  engines  which  they  supply,  when  properly  designed, 
as  to  obviate  most  difficulties  in  this  connection.  It  should  be  seen,  however  (except 
in  the  case  of  suction  producers),  that  the  connecting  mains  should  be  of  such  size  in 
section  and  length  as  to  equalize  the  minor  variations  in  both  pressure  and  production. 

Suction  Pipe. — Suction  vacuum  or  vacuum  on  the  suction  pipe  varies  in  general 
practice  from  2  to  14  ins. ;  both  of  these  extremes,  particularly  the  latter,  are  excessive. 
The  former  usually  reflects  a  porous  fire,  while  the  last  named  involves  heavy  duty 
upon,  and  an  inadequate  supply  of  gas,  to  the  engine.  Where  the  suction  exceeds 
6  ins.  the  engine  should  be  relieved  of  this  duty  by  the  interposition  of  an  ex- 
hauster. The  exhauster  should  also  be  interposed  in  all  producer  plants  above 
200  h.p. 

The  exhauster  should  be  used  where  there  is  a  plurality  of  engines  connected 
to  any  unit,  and  is  also  preferable  where  there  are  more  than  one  producer  connected 
to  the  engine.  It  is,  of  course,  necessary  where  gas  is  to  be  abstracted  for  heating 
or  furnace  work.  The  exhauster  tends  to  prevent  robbing,  and  when  water  sealed  or 
by-passed,  very  effectively  regulates  the  demand  of  supply.  It  must  be  remembered, 
however,  that  when  the  gas  is  delivered  to  an  engine  under  pressure,  where  the  engine 
has  been  designed  for  suction,  it  is  necessary  to  throttle  the  pressure  to  prevent 
"  flooding  "  or  choking  the  air  supply  in  the  mixing  chamber.  This  control  is  most 
readily  affected  by  means  of  a  small  gasometer,  or  pressure-reducing  valve,  the  former 
being  the  most  flexible  and  sympathetic. 

Coke  Oven  Gas.— A  ton  of  coal  in  coking  generally  approximates  9000  cu.ft.  of 
purified  gas  averaging  375  to  400  B.T.U.  per  cubic  foot.  Of  this  about  5000  to  5500 
is  used  in  the  heating  of  the  ovens,  leaving  a  margin  of  net  by-product  for  general 
power  purposes.  Of  this  margin  about  10%  is  required  for  the  various  mechanical 
processes  of  gas  scrubbing,  cleaning,  blowers,  exhausters,  etc. — that  is  to  say,  the 
gross  by-product  being  about  3600  cu.ft.,  about  2600  ft.  are  left  as  a  net  product 
for  the  production  of  power  for  sale  or  outside  work.  This  product  ranges  from  100 
to  175  h.p.  per  ton  of  coal  coked  per  twenty-four  hours. 

As  approximate  figures  it  may  be  taken  that  60%  of  the  heat  units  of  a  coal  are 
required  for  heating  the  retorts,  about  10%  for  various  power  purposes,  and  30% 
available  as  a  net  by-product  for  outside  use.  This  of  course  varies  with  various 
classes  of  coal  and  the  efficiency  of  different  types  of  apparatus. 

It  may  also  be  taken  as  a  tentative  estimate  that  one  ton  of  coke  is  required  for 
the  production  of  one  ton  of  iron.  Again,  depending  upon  the  particular  coal  analysis, 
the  transfer  of  coal  to  coke  may  be  approximated  at  75%. 


266 


GAS   PRODUCERS 


The  German  Otto  ovens  yield  about  4800  cu.ft.  of  gas  per  ton  of  German  coal, 
the  gas  possessing  an  average  value  of  450  B.T.U. 

Blast-furnace  Gas. — Of  the  total  quantity  of  gas  generated  in  the  blast  furnace 
plant,  about  50%  is  required  for  the  operation  of  the  plant  itself,  including  driving 


10t  Coke  per  honr 


Heat  consumption  In 
blast  furnace  52$ 


loss  11% 


FIG.  117. — Heat  Balance  of  Blast  Furnace  of  250  Tons  Daily  Capacity. 

blowing  engines,  washers,  scrubbers,  electricity,  and  the  heating  of  the  blast  furnace. 
About  50%  of  roughly  speaking  25  h.p.  per  ton  of  pig  iron  manufactured  per  twenty- 
four  hours  is  available  for  outside  work. 


FIG.  118. — Heat  Balance  of  a  By-product  Coke  Oven  of  200  Tons  Daily  Capacity. 

In  the  production  of  one  ton  of  pig  iron  there  is  produced  available  for  power 
purposes  as  a  net  by-product  approximately  90,000  cu.ft.  of  blast  furnace  gas  having 


GAS   POWER 


267 


a  heat  value  ranging  from  80  to  100  B.T.U.  per  foot,  a  fair  approximation  of  the  average 
being  90  B.T.U.,  which  usually  supplies  the  most  satisfactory  power  gas,  inasmuch 
as  the  higher  values  show  high  content  of  hydrogen  due  as  a  rule  to  jacket  leakage  of 
water  and  also  large  factor  of  CO2.  Used  under  boilers  this  gas  per  ton  usually 
produces  an  output  of  250  h.p.  hours.  To  use  in  the  gas  engine  its  efficiency  is  doubled 
mid  frequently  trebled. 

Comparison    of    Steam    and    Gas    Power. — It  remained  for  the  United  States 
Geological  Survey  in  its  testing  plant  at  Saint  Louis  to  attempt  the  use  of  any  and 


Waste  Heat  Boiler  Loss  Cooling  Water      Exhaust  heat 

A  daily  pig  Iron  production  of  250  t    yields  gas  for: 


4000  eff.  h.p.  with  Steam  Engines 


.  10000  eff.  h.p.  with  Gas  Engines 


Steam  Engine 


Heat  consumption  per  1  h.p. 


Gas  Engine 21* 

^^^xix^raaraSga 


B    Useful  work 
,.    ** 
Friction 


Kihaustheat       Boiler  loss  Producer  loss 

Annual  Cost  of  1000  eff. h.p.  at  300  x  24  hours. 


10000  Mk  69000  ilk 

Best  Steam  Engine  with  Boiler  Coal 
(U  12,00  Mk) 


1  109  000  Mk 


U  50000  Mk 

12000  Mk      8000  Mk  Interest         Fuel 

Amortisation      Cost 


Best  Gas  Engine  with  Coke  breeze 
(It  2,0011k) 


Cost  of  Upkeep 
Attendance 


FIG.  118J. — Comparative  Heat  Utilization  of  Steam  and  Gas  Engines  and  Relation  of  Heat 

Consumption  and  Annual  Cost. 


all  bituminous  coals,  lignites  and  peats,  without  reference  to  the  amount  of  sul  hur 
or  tarry  matter  to  be  found  in  the  fuel.  It  is  gratifying  to  note  that  every  bituminous 
and  semi-bituminous  coal  received  has  been  run  through  the  producer  and  that  the 
results  have  been  more  than  satisfactory. 

Relative  Results  of  Steam  and  Producer  Gas  Tests. — In  considering  the  relation 
between  the  economic  results  of  the  two  types  of  plants  under  discussion,  viz.,  steam 
and  producer  gas,  attention  is  called  to  the  fact  that  to-day  in  the  ordinary  manu- 
facturing plant  operated  by  steam  power  less  than  5r<  of  the  total  energy  in  the  fuel 
consumed  is  available  for  useful  work  at  the  machine. 


268  GAS   PRODUCERS 

AVERAGE    LOSS    IN    THE    CONVERSION    OF    ONE    POUND    OF  COAL    CONTAINING 

12,500    B.T.U.    INTO    ELECTRICITY 

H.T.U.  Per  Cent. 

Loss  in  gas  producer  and  auxiliaries 2,500  20 

Loss  in  cooling  water  in  jackets 2,375  19 

Loss  in  exhaust  gases 3,750  30 

Loss  in  engine  friction 813  6.5 

Loss  in  electric  generator 62  0.5 


Total  losses 9,500  76 . 0 

Converted  into  electric  energy 3,000  24 


Total.  .  12,500  100.00 


Especial  attention  should  be  called  to  the  fact  that  several  low  grade  fuels,  coals 
and  lignites  which  have  proved  of  little  value  or  even  worthless  under  the  steam  boiler, 
have  given  excellent  returns  in  the  gas  producer. 

The  ratios  of  the  total  fuel  per  brake  horsepower  hour  required  by  the  steam 
plant  and  producer  gas  plant  under  full  load  conditions,  not  counting  stand-by  losses, 
are  presented  below  as  derived  from  76%  coals,  6  lignites  and  1  peat. 


RATIOS    OF    FUELS    REQUIRED    PER  B.H  P.    HOUR. 

Under  Boiler -r- in  Producer.  Average.  Maximum.         Minimum. 

Coal 2.7  3.7  1.8 

Lignite 2.7  2.9  2.2 

Peat..  2.3 


In  the  case  of  the  results  for  the  producer  gas  tests  the  figures  include  not  only 
the  coal  consumed  in  gas  generator,  but  also  the  coal  used  in  the  auxiliary  boiler  for 
generating  the  steam  necessary. 

Stand-by  Losses. — It  is  probable  that  the  most  reliable  figures  obtainable  to-day 
relating  to  this  point  are  those  presented  by  Messrs.  Dowson  and  Larter  in  their 
recent  book  entitled  "Producer  Gas."  The  results  secured  by  these  gentlemen  from 
a  number  of  engineers  and  experimenters,  including  such  well  known  names  as  that 
of  Bryan  Donkin,  indicate  that  for  plants  of  about  250  h.p.  the  stand-by  losses  amount 
to  about  67  Ibs.  of  coal  per  standing  hour  for  the  steam  plant  and  to  about  4  Ibs. 
per  standing  hour  for  the  producer  gas  plant. 

It  should  again  be  noted  that  many  fuels  are  not  fit  for  use  under  boilers.  Many 
of  these  poor  fuels  have  been  used  with  the  greatest  ease  in  the  gas  producer,  thus 
opening  the  way  for  the  utilization  of  man}-  fuels  that  have  heretofore  been  regarded 
as  practically  of  no  value.  Several  of  the  poorest  grades  of  bituminous  coal  have 
shown  remarkable  efficiency  in  the  gas  producer,  and  the  lignites  and  peat  have  also 
responded  with  great  readiness  to  the  demands  of  the  gas  producer,  thus  opening  he 


GAS   POWER  269 

way  to  the  introduction  of  cheap  power  into  large  districts  that  have  thus  far  been 
commercially  unimportant  owing  to  the  lack  of  industrial  opportunities. 

Official  records  have  been  made  as  low  as  0.95  Ib.  of  dry  coal  per  hour  burned  in 
the  producer  per  electrical  horsepower  developed  at  the  switch-board;  or  0.80  Ibs.  of 
dry  coal  per  hour  burned  in  the  producer  per  brake  horsepower  per  hour,  on  the  basis 
of  an  efficiency  of  85%  for  generator  and  belt. 


CHAPTER   XI 
GAS    ENGINES 

General  Details. — Internal  combustion  engines,  where  gas  is  burned  explosively 
in  the  cylinder  itself,  have  reached  a  state  of  development  hardly  anticipated,  and 
therefore  the  gas  engine  problems  have  become  as  complex  as  the  devices  themselves. 
This  development  has  been  sufficiently  well  treated  by  competent  authorities,  and 
our  attention  will  be  here  confined  to  some  practical  details  of  operation.  The  general 


FIG.  119. — Gas  Engine  Cycles. 

theory  of  the  4-stroke  cycle  is  illustrated,  the  dotted  line  on  each  diagram  indicating 
the  stroke  represented  in  the  diagram  below  it  and  the  upper  valve  the  exhaust.  The 
pressure  exerted  by  the  explosion  of  gas  and  air  mixture  in  the  cylinder  depends  upon 
the  richness  of  the  mixture  as  shown.  The  gas  engine  charge  of  coal  gas  is  1  part  gas 
to  8-12  parts  of  air. 

The  expansion  and  compression  curves  depend  upon  the  gas  largely  as  shown 
in  the  curves.  The  pressure  at  the  time  of  explosion  rises  to  300  to  450  Ibs.  per  square 
inch,  which  drops  rapidly  until  the  exhaust  port  opens.  The  compression  is  from 
100  to  110  Ibs.  per  square  inch.  O'Conner  says  that  to  raise  the  compression  from 
10  to  100  atmospheres  requires  only  2.5  times  the  power  required  for  10  atmospheres. 
The  consumption  of  18  c.-p.  600  B.T.U.  gas  per  effective  horsepower  is  16.5  cu.ft. 
The  indicated  horsepower  developed  is  equal  to  the  mean  effective  pressure  in  pounds 

270 


GAS  ENGINES 


271 


FIG.  120. — Combustion  Pressures. 


^r.        \-/bS    I  J"""^-t-"» 


I  S  T  ft  /Bt/T/O/V      0f 


Cf    G*  S 


* 

• 
' 

rfuxit.Li.'y  O«nt. 

*y  itct~i0Ti  ^,u  - 

CoAe  Ov+i  G+J 

85 

i 

i—  •—  i 

m 

•PKffPOKTfOA/     or   CAKBOV    MONOXIDE.    IM  .VARIOUS   fl/£i.    Cr/IJES 


FIG.  121. — Comparison  of  Blast-furnace  Gas  and  Producer  Gas. 


272 


GAS   PRODUCERS 


per  square  inch  times  the  length  of  the  stroke  in  feet,  times  the  area  of  piston  in  square 
inches,  times  the  number  of  explosions  per  minute  divided  by  33,000.  The  mechanical 
efficiency  of  a  gas  engine  is  about  80  to  85%.  The  heat  efficiency,  however,  is  only 
about  28%.  The  temperature  inside  the  cylinder  rises  to  2500  or  3000°  F.  The 
temperature  of  the  exhaust  is  sufficient  frequently  to  heat  the  pipe  red  hot,  a  tem- 
perature of  about  1000°  F. 

Foundations. — As  an  arbitrary  figure,  it  is  assumed  by  many  gas  engineers  that 
the  cost  of  erecting  gas  engines  upon  foundations  supplied,  engines  being  F.  0.  B. 
cars  at  a  convenient  side  track,  for  $12.00  per  ton  complete. 

The  cost  of  erecting  producers  usually  rated  in  the  same  manner,  $6.00  to  $8.00 
per  ton  complete.  The  erection  of  complete  producer  plants  are  roughly  estimated 
at  $12.00  per  ton. 


CDO 


IL 


FIG.  122.— Floor  Foundation. 


FIG.  123. — Masonry  Gas  Engine  Foundation. 


In  calculating  concrete  foundations  for  gas  engines  where  the  natural  conditions 
are  reasonably  good  and  pinning  unnecessary,  concrete  foundations  are  usually  figured 
as  arbitrary  at  30  cents  per  cubic  foot. 

The  foundation  of  an  engine  requires  consideration.  In  small  plants  it  need  not 
be  as  elaborate  as  for  steam  engines.  The  engine  may  be  set  upon  boards  as  shown, 
or  for  more  elaborate  machinery  a  concrete  base  with  brick  top  and  anchor  bolts  is 
required. 

To  find  size  of  dry  meter  for  gas  engines,  multiply  the  brake  horsepower  X3.4 
+  5=  number  of  lights. 

The  size  of  supply  pipe  to  engine  can  be  found  by  reference  to  a  table  of  meter 
dimensions.  The  size  of  exhaust  pipe  is  thus  obtained:  From  1  to  5  b.h.p.,  1  in.  to  If 
ins.  diameter. 

Above  that  size,  diameter  in  inches  =  0.528  Xh.p.057. 

The  heat  of  exhaust  pipes  is  great,  and  likely  to  burn  wood  if  too  near.  Bends 
of  6  ins.  or  more  radius  only  should  be  used;  no  elbows  or  tees.  Turn  the  outlet  of 
the  pipe  to  look  downwards. 

To  Prevent  Excessive  Noise  in  Exhaust  Pipe. — The  pipe  can  be  carried  into  a 
drained  pit  and  surrounded  with  stones,  over  which  a  covering  of  straw  can  be  placed. 
There  are  many  ways  of  multiplying  the  exhaust,  among  which  are  those  herewith 
illustrated. 

As  an  instance  of  one  of  the  many  things  which  interferes  with  the  valves  of  a 
gas  engine,  may  be  mentioned  the  case  of  the  Fort  Dodge  Light  and  Power  Company, 
who  had  an  analysis  made  in  1907  of  a  substance  deposited  on  the  seat  of  the  mixing 
valve  of  a  gas  engine  at  Fort  Dodge,  Iowa,  which  gave  the  following: 


GAS   ENGINES 


273 


Per  Cent. 

Mineral  matter 24 . 58 

Phenoloid  bodies 17.32 

Basic  hydrocarbons 1.47 

Indifferent  hydrocarbons 56.63 

Sulphur.  ...  ." 1.42 

The   mineral   matter  was  chiefly   silica  and  contained  some  iron  and  alumina. 
The  deposit  was  supposed  to  be  due  to  tar  from  gas-house  coke. 


FIG.  124. — Gas  Engine  Exhaust  Mufflers. 

The  cause  of  a  thumping  noise  in  the  interior  of  the  cylinder  is  thus  explained: 
Single-acting  engines  thump  with  light  loads  because  the  cylinder  is  not  full  of  mixture 
and  the  compressoin  is  reduced.  In  the  vis-a-vis  engine  the  piston  connecting  rod 
running  under  is  more  liable  to  thump  than  on  the  other  side,  for  the  reason  that  the 
tendency  is  to  lift  the  piston  against  the  top  of  the  cylinder  when  the  explosion  takes 
place.  When  there  is  no  explosion,  of  course,  the  piston  rests  on  the  bottom  of  the 
cylinder.  This  up-and-down  motion  at  different  intervals  causes  the  thumping.  It 
doesn't  occur  at  the  position  of  the  connecting  rod  running  over,  with  as  much  violence. 

Oil  engines,  as  far  as  we  have  any  record  of  them,  have  not  been  built  in  powers 
above  200  horse  with  any  degree  of  success.     Therefore,  this  question  only  effects 


274 


GAS   PRODUCERS 


engines  of  small  powers.  Where  oil  is  cheap,  in  engines  of  small  powers,  the  oil  engines 
should  be  the  preferable  engine  to  use,  providing  the  customer  is  willing  to  take  the 
risk  of  getting  cheap  oils  throughout  the  entire  life  of  the  engine.  Past  history, 
however,  in  the  oil  business,  does  not  justify  this  condition  and  any  one  purchasing 
an  oil  engine,  places  themselves  in  a  position  to  use  fuel  that  is  apt  to  be  doubled  in 
price  any  time. 

Ignition. — Jump  sparks  are  usually  impracticable  under  any  high  limit  of  engine 
compression,    sparking   under   such    conditions    requiring   extremely   high    potential- 


FIG.  125. — Nurnberg  Type  of  Water  Cushion  Exhaust. 


Under  condition  of  high  compression,  the  density  of  the  charge  materially  increases 
the  electric  resistance  and  there  is  a  tendency  on  the  part  of  the  spark  to  hesitate  and 
refuse  the  gap.  Under  these  conditions  the  make-and-break  is  much  more  positive 
and  furnishes  a  hotter  and  better  timed  ignition. 

There  are  many  causes  for  early  firing,  chief  among  which  are:  Accumulation 
of  dirt  in  the  interior  of  the  cylinder  in  pockets  that  are  in  the  head.  This  dirt  becom- 
ing incandescent  and  remaining  so  until  the  fresh  mixture  comes  in,  sets  fire  to  it  and 
causes  it  to  pre-ignite.  A  bolt  sticking  into  the  cylinder,  the  end  of  which  becomes 
red  hot,  or  any  other  projection  that  becomes  red  hot,  will  cause  pre-ignition.  Any 


GAS   ENGINES  275 

kind  of  fibrous  packing  may  become  incandescent  or  in  fact  any  incandescent  particles 
will  cause  this  condition.  Premature  ignition  frequently  occurs  in  engines  from  an 
ignition  or  spark  occurring  or  being  carried  in  the  piston  packing.  This  frequently 
causes  premature  troubles,  which  may  otherwise  be  accounted  for,  and  can  only  be 
discovered  by  examination  of  the  packing  and  in  the  scraping  or  shearing  of 
same. 

Severe  premature  explosion  on  the  part  of  a  gas  engine  is  frequently  effectively 
cured  by  the  admission  of  a  small  amount  of  water  vapor  into  the  air  pipe  probably 
causing  a  reduction  of  flame  propagation  within  the  explosive  mixture.  This  arrange- 
ment is  usually  made  by  a  small  water  overflow  connection  tapped  into  the  air  pipe 
aforesaid.  In  cases  of  emergency,  an  ordinary  large  oil-can  filled  with  water  and 
horizontally  tapped  into  the  intake  has  been  successfully  used,  the  container  of  the 
can  having  one  or  more  pin  holes  in  the  top,  the  air  drawn  through  picking  up  a  certain 
amount  of  water  spray  in  its  passage,  and  humidifying  the  air  before  coming  to  the 
engine. 

Starting. — One  of  the  easiest  methods  of  starting  a  gas  engine  is  to  open  the  air 
valve  about  one-half  to  one-third,  as  soon  as  the  engine  has  started  to  move  under 
compressed  air,  to  open  the  gas  valve  gradually  until  the  explosion  occurs. 

Under  conditions  wrhere  the  gas  arises  to  the  engine  under  pressure  either  through 
the  intermediary  of  an  exhauster  blower  or  pressure  producer,  the  pressure  of  the 
gas  must  under  all  circumstances  be  reduced  to  atmospheric.  This  to  prevent  the 
choking  of  the  engine  with  gas.  It  is  often  much  easier  to  start  the  engine  in  the  way 
indicated  than  to  open  the  air  valve  entirely  right  from  the  beginning.  By  having 
a  small  opening,  not  only  the  gas  but  also  the  air  is  under  control. 

In  obstinate  cases  sometimes  results  are  obtained  when  starting  the  engine,  by 
having  the  engine  make  two  or  three  revolutions  with  the  gas  valve  entirely  closed, 
and  then  to  open  the  gas  valve  suddenly  and  immediately  prior  to  the  suction  stroke. 
These  instructions  of  course  vary  more  or  less,  as  the  individual  experience  of  both 
different  engines  and  engineers  differ  in  the  matter. 

In  the  case  of  a  multi-cylinder  engine  satisfactory  results  have  often  been  obtained 
by  starting  up  with  air  on  one  cylinder  alone,  and  after  purging  the  other  cylinders 
with  air,  to  gradually  admit  gas  upon  the  other  cylinders  until  an  explosion  is  formed, 
meanwhile  running  the  first  cylinder  entirely  with  air  pressure. 

Compression. — H.  W.  Jones,  a  gas  engine  expert,  said,  in  a  recent  article:  "We 
need  higher  compression  in  gas  engines.  Some  gas  engine  manufacturers  are  sure 
to  take  this  suggestion  in  all  seriousness,  and  act  upon  it  and  furnish  engines  that 
have  the  proper  compression.  We  ask  that  they  first  design  the  compression  chamber 
or  clearance  space  to  conform  to  the  gas  with  which  it  is  to  be  used;  then,  build  around 
this  compression  an  engine  that  will  stand  the  terrific  pressure  generated  by  the  rapid 
burning  of  the  gases;  that  they  design  the  exhaust  port  to  quickly  get  rid  of  the 
products  of  combustion;  that  their  intake  valve  be  so  constructed  as  to  allow  the 
engine  to  take  full  charge  of  gas  without  drawing  it  around  any  elbows  of  piping 
between  the  valve  and  the  gas  bag,  and  that  the  gas  comes  into  the  engine  cold;  that 
the  air  supply  is  extra  large  to  allow  the  engine  all  the  air  needed  to  properly  secure 
enough  oxygen  to  give  the  highest  and  best  efficiency  in  the  combustion  chamber, 
and  that  they  equip  their  engine  with  a  graduated  scale  cock  on  the  air  supply,  so 


276  GAS   PRODUCERS 

that  the  air  supply  can  be  regulated  when  conditions  change.     What  is  the  proper 
compression  for  an  illuminating-gas  engine?     One  authority  says: 

"  The  higher  the  compression,  the  greater  the  efficiency  and  less  gas  required  to 
produce  satisfactory  results. 

"  The  higher  the  compression,  the  cleaner  the  mixture,  for  there  is  less  space  for 
the  burned  gases  to  remain  in  the  cylinder. 

"  The  higher  the  compression  the  less  water  needed,  as  the  combustion  chamber 
is,  as  a  matter  of  course,  smaller. 

"  The  higher  the  compression  the  more  power  to  each  charge;  consequently  less 
charges. 

"The  higher  the  compression,  the  less  gas;  smaller  bills;  '  pleased  customers; 
more  of  them;  greater  sales  of  gas;  less  trouble  with  the  engine.  (This  is  a  fact.) 

"  Figured  in  pounds  by  calibrated  scale,  what  should  the  compression  be  to  give 
best  results  as  to  economy  of  fuel  per  b.h.p.  in  illuminating  gas  engines  using  650 
effective  B.T.U.  gas,  and  at  same  time  not  overtax  the  engine?  To  set  minds  at  rest 
on  the  question  of  pre-ignition,  I  know  of  an  engine  running  with  104  Ibs.;  it  is  a  15-h.p. 
engine,  2  cylinder,  vertical;  it  generates  15  h.p.  for  one  hour  or  so,  occasionally  2  or  3 
times  per  day,  but  runs  on  9  h.p.  as  an  average. 

"  Let  us  confine  ourselves  to  engines  of  5  to  40  h.p.  From  my  experience,  and 
it  has  been  varied  and  comparatively  thorough,  95  Ibs.  is  a  conservative  compression; 
this  is  when  the  engine  is  running  and  well  warmed  up;  105  Ibs.  if  engine  will  stand 
it,  and  it  will  take  something  more  than  argument  to  convince  gas  companies  or  users 
of  gas  in  engines  that  this  is  wrong." 

Cylinder  Dimensions. — The  influence  of  cooling  surface  on  clearance  volume  in 
gas  engines  is  the  subject  of  the  following  from  the  pen  of  R.  Wintzer:  It  was  the 
intention  to  determine  approximately  in  which  manner  the  gas  consumption  and  the 
maximum  output  of  a  gas  engine  is  influenced  by  the  cooling  surfaces  in  the  com- 
pression volume.  The  discussion  refers  to  the  conditions  on  a  30X42  in.  2-cylinder 
double-acting  tandem  gas  engine,  run  with  107  r.p.m.,  equal  to  749  ft.  piston  speed 
per  minute,  but  the  conditions  will  be  similar  for  engines  of  other  sizes.  From  the 
sizes  of  two  different  surfaces  they  can  compare  the  heat  carried  away  in  cooling  water. 
From  the  difference  of  the  two  losses  we  can  figure  the  difference  in  temperature  of 
the  working  medium,  and  from  the  difference  in  temperature  in  the  gas  we  can  figure 
the  difference  in  the  pressure  represented  in  the  indicator  card.  The  difference  in 
pressure  represents  then  the  gain  or  loss  for  less  or  more  cooling  surface.  The  calcu- 
lation is  made  with  three  different  cooling  surfaces  in  the  compression  volume  of  2200, 
3300  and  4400  sq.in.  In  these  limits  are  comprised  practically  all  modern  engines, 
the  surface  of  2200  sq.in.  representing  a  clearance  volume  which  is  formed  of  a  simple 
cylinder  of  a  height  corresponding  with  the  necessary  compression  volume.  Between 
3500  and  4400  sq.in.  include  most  of  the  double-acting  gas  engines  with  valves  on 
top  and  underneath  the  cylinder.  Assuming  that  the  piston  displacement  per  minute 
is  3.7  cu.ft.  per  brake  horsepower  and  that  the  suction  and  compression  line  will  cut 
the  atmosphere  line  in  the  indicator  card  at  90%,  the  volume  of  mixture  at  atmos- 
pheric pressure  will  be  3.7X0.9  =  3.33  cu.ft.  per  minute.  The  weight  of  the  same  is 
about  0.0807  Ibs.  per  cubic  foot,  therefore  the  weight  of  the  working  medium  per 
b.h.p.  hour  is  33.33x60X0.0807=16.1'  Ibs.  One  illustration  (No.  1)  shows  an 


GAS  ENGINES 


277 


CURVE  OF  COOLING  SURFACE 


p  *  EXPANSION  PRESSURE  DUE  TO 
2200  a'COOL  SURFACE 
p  =  EXPANSION  PRESSURE  DUE  TO 
8300  n*COOL  SURFACE 


FIG.  126. — Relation  of  Cooling  Surface  to  Clearance  Volume. 


278  GAS    PRODUCERS 

indicator  card,  and  the  other  (No.  2)  the  corresponding  temperature  diagram  of  an 
engine  under  average  conditions.  From  the  latter  diagram  is  developed  the  curve 
of  temperature  with  time  as  basis  given  in  No.  4.  The  temperature  of  the  cylinder 
wall  will  certainly  fluctuate  to  some  extent  during  one  cycle,  but  these  fluctuations 
will  be  very  small  in  comparison  with  the  temperature  difference  between  cylinder 
wall  and  gas.  To  simplify  the  investigation,  the  temperature  of  the  wall  is  assumed 
to  be  constant  at  390°  F.  Right  over  the  temperature  diagram  is  shown,  in  No.  3, 
the  corresponding  size  of  the  cooling  surface  which  consists  of  a  constant  one  equal 
to  the  surface  in  the  clear  volume  and  the  variable  one  corresponding  to  piston 
displacement. 

Piston  displacement  per  b.h.p.  min.  =  3.7  cu.ft.     3.7X0.9  =  3.33  cu.ft.  of  mixture 
at  atmospheric  pressure. 

W=161  Ibs.  of  mixture  used  per  b.h.p.  hour  (0.0807  Ibs.  per  cu.ft.). 
S\  =  Surface  exposed  to  gas,  2200  sq.in.  cooling  surface. 
S2  =  Surface  exposed  to     gas,  3300  sq.in.  cooling  surface. 
2  =  390°  F.  =  average  temperature  of  cooling  surface,  constant. 

<i  =  Gas  temperature,  degrees  F.,  for  2200  sq.in.  cooling  surface. 

^2  =  Gas  temperature,  degrees  F.,  for  3300  sq.in.  cooling  surface. 

J  =  Joule's  equivalent  =  778  ft. Ibs. 
Cv  =  Specific  heat  at  constant  voulme. 

§i  =  Heat  absorbed  by  cooling  water,  2200  sq.in.  cooling  surface. 
52  =  Heat  absorbed  by  cooling  water,  3300  sq.in.  cooling  surface. 

Pi  =  Pressure  from  indicator  card,  2200  sq.in.  cooling  surface. 
p2  —  Pressure  from  indicator  card,  3300  sq.in.  cooling  surface. 

If  If 

The  last  two  terms  are  so  small  as  to  be  neglected. 


Therefore  the   work  gained  by  the   smaller   cooling  surface   is   represented  by 


j  p2dv  —  I  pidv 


The  heat  transmitted  in  each  time  unit  to  the  cooling  surface  will  be  proportional 
to  the  surface  exposed  at  that  time,  and  the  difference  between  the  wall  and  gas  tem- 
perature in  said  moment  and  the  constant  coefficient  depending  on  the  conditions  of 
the  wall.  We  do  not  know  this  latter  coefficient,  therefore  we  cannot  determine  at 
present  the  absolute  amount  of  heat  carried  away,  but  we  can  compare  different 
engines  with  different  cooling  surfaces.  The  three  curves  given  in  the  diagram  No.  5 


GAS  ENGINES  279 

represent  this  heat  absorbed  in  the  cooling  water  by  the  walls.  In  diagram  is  shown 
the  total  area  of  each  curve  Qi,  $2  and  Q3,  with  height  and  the  surface  in  the  clearance 
volume  as  basis.  Taking  a  cylinder  with  3300  sq.in.  cooling  surface  as  an  average 
good  engine,  with  a  gas  consumption  of  10,000  B.T.U.  per  b.h.p.  hour,  we  know  from 
tests  that  about  33%  of  the  total  heat  admitted  to  the  engine  is  carried  away  in  the 
cooling  water.  This  will  give  us  a  scale  for  Q  curve,  and  we  could  determine  the  heat 
carried  away  in  the  cooling  water  by  the  other  engines,  supposing  that  all  would  run 
with  the  same  average  of  temperature  of  the  cylinder  walls. 

At  the  first  glance  it  would  look  as  if  the  maximum  output  and  also  the  gas 
consumption  of  the  engine  would  improve  proportioning  this  Q  curve  with  the  decrease 
in  cooling  surface,  but  that  is  far  off.  The  effect  will  be  only  that  by  less  deduction 
of  the  heat  in  the  cooling  water  the  gas  temperature  of  the  gas  in  the  cylinder,  and 
therewith  the  pressure,  will  rise.  Assuming  a  heat  consumption  of  3300  B.T.U.  per 
b.h.p.  hour  in  the  cooling  water  for  the  medium  engine,  we  will  be  able  to  determine 
the  rise  or  fall  in  temperature  for  the  other  engines.  If  t2  in  diagram  No.  4  represents 
the  temperature  for  3300  sq.in.  cooling  surface,  this  temperature  will  rise  for  2200 
sq.in.  cooling  surface  corresponding  to  the  area  represented  by  the  curves  q\  and  q% 
in  diagram  No.  5.  If  Cv,  equal  to  0.189  B.T.U.  per  pound,  is  the  specific  heat  of  the 
gas  at  constant  volume,  we  have  the  relation: 


The  second  part  of  this  formula  represents  a  heat  equivalent  of  the  difference  of  expan- 
sion work  for  the  two  gases,  "and  is  so  small  compared  with  the  first  member  that  it 
can  be  neglected.  The  heat  absorbed  for  2200  sq.in.  surface  is  calculated  by  using 
the  temperature  of  the  gas  expanding  with  3300  sq.in.  clearance  surface,  instead  of 
re-calculating  the  gas  temperature  for  2200  sq.in.  and  then  using  the  latter  for  deter- 
mining the  final  temperature  for  ti  ;  also  this  error  is  so  small  that  it  can  be  neglected. 
By  neglecting  these  two  errors  we  get  a  curve  for  t\  and  pi  which  is  higher  than  it 
should  really  be. 

If  />2  in  No.  7  represents  the  indicator  card  for  3300  sq.in.  cooling  surface,  you  can 
calculate  the  pressure  for  2200  sq.in.  surface  according  to  absolute  temperature  in 
each  moment. 


The  work  really  gained  is  an  increase  of  the  mean  effective  pressure  represented 
by  the  area  between  the  curves  for  pi  and  p2  in  diagram  No.  7.  For  the  larger,  the 
cooling  surface  for  4400  sq.in.  the  loss  is  found  in  a  similar  way.  The  mean  effective 
pressure  and  the  corresponding  gas  consumption  are  drawn  again  in  diagram  No.  6, 
and  show  clearly  that  the  gas  consumption  is  changing  in  quite  a  different  ratio  than 
the  heat  absorbed  in  the  cooling  water. 

This  investigation  does  not  represent  absolute  results,  but  only  a  fair  comparison 
between  otherwise  equal  engines  with  different  cooling  surfaces.     They  can  be  used 


280  GAS   PRODUCERS 

for  example  in  the  following  way:  A  certain  kind  of  exhaust  valve  on  a  30X42  in. 
engine  may  increase  the  cooling  surface  in  the  compression  volume  for  300  sq.in.  over 
first  engine.  If  both  engines  are  run  with  the  same  temperature  of  the  walls  and  if 
the  heat  absorbed  in  the  cooling  water  of  the  first  engine  is  3300  B.T.U.  per  b.h.p  hour, 
the  same  in  the  second  one  will  be  3518  or  6.6%  more,  but  the  gas  consumption  will 
rise  from  10,000  B.T.U. 's  per  b.h.p.  hour  to  10,159,  or  1.59%  more.  This  percentage 
may  come  down  to  1.3  or  1.4%  when  the  two  factors  are  taken  into  consideration 
which  are  neglected  in  the  above  deduction.  Most  of  the  heat  which  is  saved  in  the 
first  case  in  the  cooling  water  is  spent  again  in  heating  the  exhaust  gases. 

The  results  of  this  investigation  agree  very  nicely  with  the  well-known  fact  that 
the  gas  consumption  of  an  engine  does  not  at  all  decrease  in  the  same  ratio  as  a  saving 
is  made  in  the  heat  carried  away  in  the  cooling  water.  It  agrees  also  with  the  result 
which  M.  L.  Letombe  of  Lille,  France,  got  recently  from  many  different  tests  and 
experiments,  that  "  the  total  heat  carried  away  in  the  cooling  water  and  in  the  exhaust 
is  very  nearly  a  constant." 

Cooling  Water. — In  regard  to  the  question  of  the  total  amount  of  water  used  per 
b.h.p.  in  engines  with  and  without  cooled  pistons,  the  temperature  of  the  water  has 
to  be  taken  into  consideration.  Assuming  60°,  we  are  quite  safe  in  stating  while  the 
water  runs  to  waste,  that  the  engine  will  consume  not  to  exceed  5  gallons  per  b.h.p. 
rating  per  hour.  However,  such  statements  should  not  be  used  with  a  customer 
unless  the  customer  is  given  to  understand  that  he  should  supply  an  excess  capacity. 
It  is  much  better  to  state  that  7  to  8  gallons  are  required  as  the  tendency  on  their  part 
is  to  put  in  pumping  arrangements  to  suit  your  statements,  rather  than  to  have  a 
surplus.  When  cooling  towers  are  used  three-fourths  to  one  gallon  will  take  care  of 
evaporation  losses. 

No  recoixl  of  the  amount  of  water  for  the  pistons  alone  has  ever  been  made  that 
we  have  any  record  of.  It  is  fair,  howyever,  to  assume  that  one-third  of  the  total 
consumed  by  the  engine  would  be  the  amount  required  for  the  pistons,  two-thirds 
for  exhaust  valve  and  jackets  and  heads. 

If  the  plant  is  so  situated  that  there  is  plenty  of  ground  around  it,  it  is  best  to 
put  in  a  concrete  basin  in  which  the  depth  of  the  water  would  be  not  to  exceed  18  in. 
This  basin  should  be  rectangular  in  shape  and  as  a  sample  dimension  for  a  1000  h.p. 
plant,  should  be  about  8  ft.  wide  by  40  ft.  long.  Erect  at  the  side  of  this  basin  an 
ordinary  construction  like  a  stairway  in  which  the  tread  would  not  exceed  6  in. 
and  the  step  a  like  amount.  This  structure  is  to  be  built  of  wood.  The  height  of  it 
would  depend  somewhat  upon  the  cooling  effect  required.  Discharge  the  water  into 
a  long  trough  at  the  top,  permitting  it  to  overflow  and  flow  down  the  steps.  This 
is  about  the  cheapest  and  most  effective  cooling  system. 

If  the  engines  are  located  so  that  you  have  not  the  ground  area,  there  are  a  number 
of  tower  cooling  systems  on  the  market,  among  the  best  of  which  are  the  Barnard, 
a  system  built  by  the  Sturtevant  Company,  and  the  Boston  Blower  people  also  build 
a  very  good  system. 

Another  good  method  is  to  discharge  the  water  over  a  basin  through  ordinary 
spray  pipes,  like  a  spray  fountain;  this  is  cheap  and  very  effective.  Scrubber  water 
can  be  used  over  again  if  the  coal  is  not  too  high  in  sulphur,  and  if  it  is  too  high  it 
can  be  neutralized  by  soda. 


GAS   ENGINES 


281 


Usually  140°  is  the  maximum  jacket-water  temperature  allowed  as  the  temperature 
of  discharge  of  gas  engines,  that  is,  the  maximum  temperature  under  which  the  engine 
is  entirely  safe.  There  is  no  doubt,  however,  that  a  higher  temperature  than  this 
can  be  maintained  with  perfect  safety,  but  by  keeping  the  temperature  too  high  or 
too  near  the  maximum,  any  intermission  or  short  stoppage  of  water  supply,  or  extra 
heavy  load  on  the  engine  brings  it  too  near  the  danger  point.  The  temperature  of 
the  jacket  water  mostly  effects  the  lubricants.  Of  course  where  water-cooled  pistons 
are  used,  it  is  very  dangerous  indeed  to  allow  the  temperature  of  the  water  in  the 
piston  to  suddenly  rise  for  the  reason  that  it  expands  the  pistons  and  is  liable  to  cause 
it  to  stick;  so  we  would  advise  running  the  discharge  water  through  the  piston  of  the 
engine  at  a  lower  temperature  .than  that  of  the  jacket  water.  The  very  best  results 
would  be  obtained  by  running  the  water  at  its  maximum  temperature  at  all  times, 
because  all  the  heat  that  is  wasted  through  this  medium  is  against  the  economy  of 
the  engine.  General  practice,  however,  seems  to  set  this  temperature,  as  stated, 
although  some  have  had  excellent  results  with  160°. 

Our  experience  goes  to  show  that  the  consumption  of  ten  gallons  of  water  is 
required  as  an  average  for  water  jacket  and  scrubbers  per  h.p.  capacity.  Where  open 
tanks  are  used  for  cooling  the  evaporation  loss  may  be  figured  at  about  10%.  Others 
say  that  where  cooling  water  is  running,  a  waste  allowance  of  8  to  10  gallons  of  water 
at  60°  F.  should  be  made  per  b.h.p.  hour.  Where  cooling  towers  are  used,  from  £  to 
1  gallon  per  hour  will  take  care  of  the  evaporation.  Sometimes  the  circulation  is  due 
to  the  temperature  of  the  water  and  sometimes  it  is  obtained  by  rotary  pumps. 

CAPACITIES  OF  ROTARY  PUMPS— (SIEBEL) 


Dimensions  of  Shell. 

Diameter  of  Suction 
and  Discharge. 

Revolutions  per 
Minute. 

Size  of  Pulleys. 

Gallons  per  Minute. 

4X4       .          ... 

H 

130  to  150 

2^X7 

30 

4X4       

U 

130  to  150 

25 

4X4  

1 

130  to  150 

20 

6X6  

2 

120  to  140 

3^X12 

40  to  50 

6X6  

U 

120  to  140 

3^X12 

50  to  60 

6X6 

2 

120  to  140 

3^X18 

75  to  100 

Brewers 
6X6                 

2 

100  to  120 

5   X20 

Barrels  per  Hour. 
120 

7X8  

3 

100  to  120 

4*X18 

150  to  200 

8X8 

3  or  4 

100  to  120 

5   X20 

200  to  250 

8X8 

3  or  4 

100  to  120 

6   X24 

200  to  250 

8X12..    .    . 

4 

100  to  120 

6   X24 

300  to  350 

Soap. 
8X12  

4 

100  to  120 

6   X24 

Pounds  per  Minute. 
1200 

Anti-Pulsators. — When  a  gas  engine  is  connected  on  city  gas,  and  to  a  compara- 
tively small  street  main,  its  operation  will,  unless  special  precautions  are  taken,  cause 
a  fluctuation  in  pressure  which  may  effect  the  use  of  lighting  and  cooking  appliances 
in  the  neighborhood.  What  means  would  you  employ  to  prevent  such  a  fluctuation 
in  pressure  from  being  produced  in  the  street  main  when  the  engine  is  running? 

The  question  was  brought  up  and  discussed  at  a  meeting  of  the  American  Gas  Light 
Association  and  several  methods  of  overcoming  the  fluctuation  of  pressure  were 
described. 


282 


GAS   PRODUCERS 


The  simplest  method  which  only  applies,  however,  where  the  lead  is  fairly  constant, 
is  to  put  a  stopcock  on  the  inlet  to  the  gas  bag  and  by  partly  shutting  the  cock,  compel 
the  gas  to  pass  into  the  bag  at  a  practically  uniform  rate,  just  sufficient  to  supply  the 
quantity  of  gas  required  by  the  engine.  The  bag  acts  as  a  reservoir,  which  is  emptied 
when  the  engine  draws  gas,  and  is  filled  again  during  the  interval  between  explosions, 
and  as  the  pull  on  the  portion  of  the  pipe  in  front  of  the  stopcock  is  kept  more  constant 
the  fluctuation  in  pressure  is  reduced.  This  method  will  give  slightly  better  results 
when  two  bags  are  used  in  tandem  instead  of  one.  When  it  is  employed  care  should 
be  taken  not  to  shut  off  the  stopcock  to  such  an  extent  as  to  prevent  the  engine  from 
getting  all  the  gas  it  requires  and  thus  to  prevent  it  from  developing  the  power  needed. 

A  small  gas  holder  will,  under  the  same  conditions,  absolutely  prevent  the  passing 
back  to  the  street  main  any  fluctuation  in  pressure  no  matter  how  much  the  lead 
varies,  but  such  a  holder  is  comparatively  expensive. 

All  of  these  methods  employ  the  same  principle:  that  of  having  a  store  of  gas  fed 
to  an  accumulator  from  which  the  engine  can  draw  its  supply  without  reducing  the 
pressure  as  much  as  if  it  drew  directly  from  the  service. 

Lubrication. — Gas  engines  require  more  lubricating  oil  than  steam  engines,  espec- 
ially in  the  cylinders.  The  amount  of  oil  used  in  gas  engines  per  h.p.  hour  runs,  in 
small  units,  about  0.001  gallon  per  b.h.p.  hour. 

It  can  be  stated  that  the  gas  engine  in  its  bearings,  crank  pin,  etc.,  will  not  use 
any  more  oil  than  a  steam  engine,  but  that  the  cylinders,  if  single  acting,  will  use  four 
times  as  much  oil.  The  reason  for  this  is  because  each  cylinder,  whether  steam  or  gas 
engine,  requires  practically  the  same  amount  of  oil  to  lubricate  it,  the  gas  engine  being 
four  cycle.  It  takes  four  times  the  displacement  to  give  the  same  power  as  the  steam 
engine.  Therefore  in  proportion  to  power  the  cylinder  oil  consumed  in  a  gas  engine 
would  be  four  times  that  of  a  steam  engine.  As  an  average  throughout,  0.2  gallon 
per  200  b.h.p.  hours  is  a  very  fair  statement  and  is  easily  accomplished. 

Our  most  successful  operation  has  been  with  Enterprise  gas  engine  oil. 

Viscosity  of  Mineral  Oils. — The  following  two  tables  contain  the  results  of  a 
number  of  experiments  in  the  viscosity  of  mineral  oils  derived  from  petroleum 
residues  and  used  for  lubricating  purposes: 

VISCOSITY   OF   MINERAL  OILS 


Density,  Water=l. 

Flashing  Point, 
Degrees  C. 

Burning  Point, 
Degrees  C. 

Specific  Viscosity,  Water  at  20°  C.  =  l. 

20° 

50° 

100° 

0.931 

243 

274 

11.30 

2.9 

0.921 

216 

246 

7.31 

2.5 

0.906 

189 

208 

3.45 

1.5 

0.921 
0.917 
0.904 

163 
132 
170 

190 
168 
207 

8.65 

27.80 

2.8 
2.6 
1.7 

2.65 

0.891 

151 

182 

4.77 

1.86 

1.3 

0.878 

108 

148 

2.94 

1.48 

0.855 

42 

45 

1.65 

0.905 

165 

202 

3  .  10 

1.5 

0.894 

139 

270 

7.60 

3.  oo 

1.3 

0.866 

90 

224 

2.50 

1.50 

GAS   ENGINES 

The  several  groups  in  this  table  are  from  the  different  distillates. 

VISCOSITY   OF   OILS   BY   TRADE   NAME 


283 


Name  of  Oil. 

Density. 

Flashing  Point, 
Degrees  C. 

Burning  Point, 
Degrees  C. 

Viscosity  at 
19°  C.,  Water=l. 

Cylinder  oil  

0.917 

227 

274 

19.1 

Machine  oil  

0.914 

213 

260 

10  2 

Wagon  oil  .          

0.914 

148 

182 

8  0 

\\  a(roii  oil  .          

0.911 

157 

187 

7  0 

Xuptha  residue  

0.910 

134 

162 

5  5 

Oleo  naphtha  

0.910 

219 

257 

12.1 

Oleo  naphtha  

0.904 

201 

242 

6.6 

Oleo  naphtha  

0.894 

184 

222 

2  6 

Oleonid  

0.884 

185 

217 

2.8 

Oleonid   best  quailty  

0.881 

188 

224 

2  0 

Olive  oil  

0.916 

2.2 

Whale  oil                      

0.879 

0  9 

Whale  oil  .           

0.875 

0  8 

Engine   Tests. — The  following  tabulated  data  have  been  compiled  by  L.  L.  Brewer 
from  a  report  on  general  European  practice: 


WEIGHTS  AND   FLOOR   SPACE 


Weights. 

B.H.P. 

R.p.m. 

Builder. 

No.  of 
Cylinders 

Strokes 
per 
Cycle. 

Single  or 
Double 
Acting. 

Cylinder 
Arrange- 
ment. 

Eng.  with- 

Flywheel. 

Square  Feet 
Floor  Space 
per  B.H.P. 

out  F.  W. 

For 

For 

Blow. 

Dynamo. 

100 

150    Cockerill 

1 

4 

s. 

Sc 

45000 

9000 

21100 

2.05 

200 

105 

" 

1 

4 

s. 

Sc 

83000 

25000 

58500 

1.81 

250 

150 

<  « 

2 

4 

s. 

.  Td 

65000 

10000 

23400 

1.24 

300 

120 

Deutz 

1 

4 

s. 

Sc 

83500 

35000 

81800 

2.07 

300 

120 

<  < 

2 

4 

s. 

Tw 

101000 

14000 

32800 

1.52 

300 

140 

« 

4 

4 

s. 

d.  tw 

110000 

3500 

8200 

1.32 

600 

80 

Cockerill 

1 

4 

s. 

Sc 

207000 

100000 

234000 

0.99 

600 

130 

<  t 

2 

4 

s. 

Td 

185000 

46000 

107500 

1.13 

600 

110 

Oechelhaeuser 

1 

2 

s. 

Sc 

143000 

48000 

112000 

1.23 

600 

130 

Deutz 

2 

4 

s. 

Tw 

158000 

28000 

65500 

1.67 

600 

130 

1  1 

4 

4 

s. 

d.  tw. 

189000 

7000 

16400 

1.08 

600 

110 

Kurt  ing 

1 

2 

D. 

Sc 

136500 

18000 

42200 

1.11 

750 

90 

N  urn  berg 

1 

4 

s. 

Sc 

297000 

115000 

26900 

1.03 

1200 

80 

Cockerill 

2 

4 

s. 

Td. 

365000 

95000 

222000 

0.68 

1200 

130 

Deutz 

4 

4 

s. 

d.  tw 

354000 

14000 

32800 

1.01 

1200 

120 

N  urn  berg 

4 

4 

s. 

d.  tw 

280000 

16000 

37400 

0.94 

1200 

110 

Oechelhaeuser 

2 

2 

s. 

Tw 

260000 

16000 

37400 

0.90 

1200 

110 

Korting 

2 

2 

D. 

Tw 

250000 

4500 

10500 

0.90 

1400 

110 

Cockerill 

2 

4 

D. 

Td 

374000 

8600 

20000 

0.42 

284 


GAS   PRODUCERS 


GAS  CONSUMPTION 


Engine. 

Cubic  Feet  per 
B.H.P.  Hour. 

Heat  Value  in 
B.T.U. 

B.T.U.  per  B.H.P. 

Hour. 

Deutz  .  .                  

135 

100 

13500 

Cockerill  ....          

116.5 

110 

12800 

Oechelhaeuser                                .        

107.5 

103 

11050 

Korting                  

87.6 

130 

10620 

Auhalt                 

95.2 

101 

9620 

Premier               

70 

135 

9100 

AVERAGE  AMERICAN  PRACTICE 


Load  per  cent    .             

125 

100 

80. 

50 

25 

Cubic  feet  per  b.h.p.  hour  

115 

122 

137.5 

163 

200 

The  main  considerations  affecting  the  consumption  of  lubricating  oil  and  cooling 
water  are  the  dimensions  of  the  engines,  the  larger  the  dimensions  the  greater  disad- 
vantage to  the  engine.  The  average  cooling  water  consumption  is  20  gallons  per 
b.h.p.  hour.  Lubricating  oil  varies  between  0.0045  to  0.0055  pint  per  b.h.p.  hour. 
The  ability  of  the  engineer  in  charge,  however,  has  considerable  effect  on  the  above 
results. 

The  following  figures  give  the  average  efficiencies: 


SINGLE-ACTING  FOUR-CYCLE  ENGINES 

One  cylinder 85  to  90% 

Two  cylinder 80  to  85% 

Four  cylinder 75  to  85% 


SINGLE-ACTING  TWO-CYCLE  ENGINES 
One  cylinder 78  to  82% 

DOUBLE-ACTING  TWO-CYCLE  ENGINES 
One  cylinder 70  to  75% 


Load  Factors. — A  committee  of  the  Institute  of  Civil  Engineers  in  1906  made  a  re- 
port declaring  that,  on  account  of  the  difference  in  their  operation,  different  standards 
from  those  of  steam  engines  should  be  used  in  comparing  gas  engines.  The  report 
recommends  comparing  the  engines  to  an  ideal  fulfilling  the  following  conditions : 
(1)  The  reception  and  rejection  of  heat  should  take  place  as  nearly  as  may  be  in  the 
same  way  as  in  the  actual  engine;  (2)  there  should  be  no  heat  losses  due  to  radiation, 
conduction,  leakage,  or  imperfect  combustion;  (3)  data  for  numerical  evaluation 
of  the  standard  should  be  ascertainable  by  simple  measurements;  (4)  the  expression 
for  the  efficiency  should  be  a  simple  one. 

The  committee  recommended  that  the  ideal  standard  engine  be  taken  to  work 
with  a  perfect  gas  of  the  same  density  as  air,  and  that  it  be  a  perfect  air-gas  engine 
operated  between  the  same  maximum  and  minimum  volumes  as  the  actual  engine, 
receiving  the  same  total  amount  of  heat  per  cycle,  but  without  jacket  or  radiation 
loss,  and  starting  from  one  atmosphere  and  the  selected  initial  temperature  of  139°  F. 
The  actual  efficiencies  of  all  ordinary  gas  engines  vary  between  0.5  and  0.6  of  the 
efficiency  of  the  air-engine  standard. 

Three  engines  were  tested,  from  the  results  of  which  tests  the  following  figures 
were  taken: 


GAS   ENGINES 


285 


Size  engine                 

5  i.i 

i.P. 

25  i. 

H.P. 

56  i. 

H.P. 

Loud                                   

Half 

Full 

Half 

Full 

Half 

Full 

I  h  p                                       

3.6 

5.72 

14.5 

25.9 

34  .  1 

56.3 

Bhp.                  

2.87 

5.20 

10.82 

20.9 

27.9 

52.7 

Alechanical  efficiency  •             

0.80 

0.90 

0.75 

0.80 

0.82 

0.94 

Net  B  T  U  per  hour               

32260 

49630 

117200 

187700 

267500 

450600 

Thermal   i  h  p  ,  efficiency,  per  cent  

28.0 

29.0 

31.5 

35.0 

32.5 

31.8 

Thermal   b  h  p    efficiency   per  cent  

22.4 

26.1 

23.6 

28.0 

26.7 

29.9 

Thermal  efficiency  standard  

0.496 

0.496 

0.496 

0.496 

0.49 

0.49 

Relative  efficiency  i  h  p    per  cent  

56.4 

58.4 

63.5 

70.6 

66.3 

65.0 

Relative  efficiency  b  h  p    per  cent  

45.2 

52.6 

47.6 

56.4 

54.5 

61.0 

Cubic  feet  per  i.h.p  

15.78 

15.33 

13.77 

12.78 

13.67 

13.94 

Cubic  feet  per  bhp                    

19.80 

16.87 

18.45 

15.84 

16.70 

14.90 

Air'  ffas   ratio                   

8.49 

9.15 

8.42 

9.17 

7.97 

8.27 

GUARANTEED  AVERAGE  THERMAL   EFFICIENCY   OF   A   GAS   ENGINE 

Effective  B.T.U. 
Load  1(  actor.  ,  ,        , 

per  b.h.p.  hour. 

Single-cylinder  engine,  at  rated  load 11,000 

75%  load 12,000 

50%  load 13,000 

33%  load 17,000 

Double-cylinder  engine,  rated  load 10,700 

75%*  load 11,500 

50%  load 12,700 

33%  load 15,000 

Four-cylinder  engine,  rated  load 10,500 

75%  load 11,300 

50%  load 12,500 

33%  load 14,500 

HORSE  POWER  AT  VARIOUS  ALTITUDES. 


B»' 

ix* 

s^ 

J      6  000  

T  g'p 

_.,,=!_. 

UJ 

i             '  *'  ' 

^^ 

-x"*" 

^* 

^^^ 

^>  '* 

-^ 

Sea  Level  ^^  „,  

90  85  80  75  70 

PER  CENT  OF  BRAKE  HORSE  POWER  AT  SEA  LEVEL 

FIG.  127. — Influence  of  Altitude  on  Horsepower. 


65       63 


286  GAS    PRODUCERS 

Utilizing  Exhaust  Gases.— By  the  use  of  engine  exhaust  gases  in  suitably  designed 
heaters  attached  to  the  engine  exhaust  pipe,  from  2  to  3  Ibs.  of  steam  per  b.h.p.  per 
hour  can  be  raised  up  to  60  Ibs.  pressure.  The  author's  practice  is  to  raise  to  about  5  Ibs. 
pressure  and  by  use  of  engine  jacket  water  possibly  5  Ibs.  per  b.h.p.  can  be  attained. 
Where  hot  water  is  required,  as  around  chemical  works,  etc.,  this  is  added  economy 
to  the  gas  plant. 

Cecil  Poole,  in  his  article  upon  the  regeneration  of  exhaust  gas  from  gas  engines, 
says: 

"  A  hot- water  heating  system,  as  an  adjunct  to  a  gas-power  plant,  could  easily 
utilize  between  60  and  70%  of  the  exhaust  heat  and  all  of  the  heat  in  the  discharged 
jacket  water.  Such  an  auxiliary  system  would  bring  the  gas  engine  nearer  to  the  steam 
engine  in  applicability  where  sensible  heat  must  be  supplied  by  the  power  plant. 
There  would  still  be  the  drawback,  however,  that  a  gas-power  plant  would  not  furnish 
as  much  heat  as  a  steam-power  plant  of  the  same  output.  For  example,  with  35  Ibs. 
of  jacket  water  per  b.h.p.  hour  discharged  at  140°  F.,  and  the  exhaust  gases  containing 
3800  B.T.U.  at  1600°  absolute  temperature,  the  following  figures  are  obtained  for  the 
gas  plant : 

Heat  to  raise  35  Ibs.  of  water  from  140  to  190°  F -1750  B.T.U. 

1750-^0.85  =  2059  B.T.U. 
Temperature  range  of  exhaust  gases  in  the  heater..  =  1600  —655  =  945° 

Heat  available  in  gases =3800X945-:- 1600  =  2244  B.T.U. 

Heat  rejected  by  heater '. =185  B.T.U. 

Assuming  that  the  water  was  cooled  in  the  radiating  pipes  to  70°  F.,  the  heat 
units  delivered  in  sensible  heat  to  warm  the  building  would  be  4200  B.T.U.  per  b.h.p. 
hour  of  engine  output  at  full  load. 

A  non-condensing  steam  engine  of  high  efficiency  will  easily  furnish  25,000  to  26,000 
B.T.U.  per  b.h.p.,  in  the  latent  heat  of  evaporation  contained  in  the  exhaust  steam. 
This  is  obviously  about  six  times  as  much  heat  as  the  gas  engine  could  supply.  How- 
ever, a  condensing  steam  engine  can  supply  no  heat  whatever,  while  the  gas  engine  is 
able  to  supply  about  4000  heat  units  per  b.h.p.  hour  and  do  the  same  amount  of  work, 
with  a  consumption  of  only  one-third  the  quantity  of  fuel. 

In  a  gas  engine  the  exhaust  leaves  the  cylinder  at  a  high  temperature  and  thus 
carries  away  the  latent  and  sensible  heat  of  the  water  it  contains.  Opinion  differs  as 
to  which  heat  value  should  be  used  in  estimating  the  heat  efficiency  in  a  gas  engine. 
In  Germany,  England,  and  America  the  low  value  is  used  largely;  in  France  the  high 
value,  on  the  basis  that  the  producer  should  be  credited,  as  is  the  boiler,  with  the  heat 
value  it  gives  the  gas.  To  utilize  more  fully  the  heat  of  the  gas  or  steam  is  considered 
a  function  of  the  engine,  and  a  loss  not  chargeable  to  the  producer. 


CHAPTER   XII 
INDUSTRIAL   GAS  APPLICATIONS 

Comparison  of  Industrial  Fuels. — The  following  table  is  given  by  the  Morgan 
Construction  Co.  showing  the  comparison  between  the  cost  of  a  ton  of  coal  and  1000 
cu.ft.  of  natural  gas: 

Cost  of  2000  Ibs.  Value  of  1000  cu.ft.  Value  of  One  Gallon 

of  Coal.  of  Natural  Gas,  Cents.  Fuel  Oil,    Cents. 

$0.75  5i  1 

1.00  6* 

1.25  7| 

1.50  9  1.35 

1.75  lOJ 

2.00  11*  1.7 

2.50  ...  2.1 

3.00  ...  2.5 

It  is  estimated  that  where  a  furnace  temperature  of  say  2700  degrees  is  to  be 
obtained,  at  least  50%  in  fuel  economy  is  obtained  through  the  use  of  gas  firing,  by 
reason  of  the  heat  regained  through  the  regenerator  or  recuperator.  This  of  course 
is  impracticable  with  oil  or  direct  coal  firing. 

The  Industrial  Gas  Co.  make  the  following  comparison  between  the  value  of  fuels; 
in  each  instance  the  figures  are  based  upon  fuel,  air  and  gas  regenerators  for  the 
producer  gas: 

Coke  and  anthracite :  One  ton  of  2000  Ibs.  when  burned  directly  in  connection 
with  heating  operations  is  displaced  by  1000  Ibs.  bituminous  slack  or  run  of  mine  coal 
burned  in  the  producer. 

Pea,  anthracite,  and  bituminous  coal:  One  ton  of  2000  Ibs.  when  burned  directly 
in  connection  with  heating  operations  is  displaced  by  900  Ibs.  bituminous  run  of  mine 
or  slack  burned  in  the  producer. 

Fuel  oil:  One  gallon  fuel  oil  burned  without  regeneration  is  displaced  by  9£  Ibs. 
bituminous  run  of  mine  or  slack  coal  burned  in  the  producer. 

Natural  gas :  One  thousand  cubic  feet  of  natural  gas  burned  without  regeneration 
is  displaced  by  75  Ibs.  bituminous  run  of  mine  or  slack  coal  burned  in  the  producer. 

For  bending  heats,  tempering,  hardening,  annealing,  baking,  roasting,  drying, 
soldering,  tinning,  galvanizing,  singeing,  and  other  processes  requiring  heats  no  higher 

287 


288 


GAS   PRODUCERS 


than  1800°  F.,  other  fuels  are  displaced  by  the  following  amounts  of  "buckwheat" 
anthracite  coal,  in  the  producer  and  burned  with  full  recuperation. 

Natural  gas:    1000  feet  displaced  by  150  Ibs. 

City  gas:    1000  ft.  displaced  by  100  Ibs. 

Anthracite  coal  and  coke:    1  ton  of  2000  Ibs.  displaced  by  1800  Ibs. 

Pea  coal  and  bituminous  coal:   1  ton  of  2000  Ibs.  displaced  by  1620  Ibs. 

Fuel  oil:    1  gallon  displaced  by  19  Ibs. 

In  firing  furnaces  with  producer  gas,  the  Hawley  Down-Draft  Furnace  Co.  recom- 
mend that  the  gas  be  admitted  at  ^  Ib.  more  pressure  than  the  air  from  the  blower. 
The  company  rates  their  furnaces  at  one-third  the  capacity,  when  firing  with  producer 


FIG.  128. — Mixing  Burners  for  Hawley  Down-Draft  Kilns. 


gas  as  when  firing  with  oil,  the  oil  pressure  being  about  30  Ibs.  The  air  being  12 
to  16  ounces  pressure  when  melting  copper  or  bronze  and  11.5  Ibs.  when  melting  iron 
or  steel.  The  section  shows  how  the  pressure  of  air  and  gas  are  regulated. 

Heat  Recovery. — In  considering  any  gas  fuel,  the  first  question  is  what  percent- 
age of  the  energy  of  the  fuel  converted  is  delivered  with  the  gas?  Producer  gas, 
though  the  lowest  in  energy,  can  be  produced  more  cheaply  per  unit  of  heat  than 
any  other.  Yet  in  the  old  Siemens  producer,  practically  all  the  heat  of  primary 
combustion — that  is,  the  burning  of  solid  carbon  to  carbon  monoxide — was  lost,  as 


INDUSTRIAL  GAS   APPLICATIONS  289 

little  or  no  steam  was  used  in  the  producer,  and  nearly  all  the  sensible  heat  of  the 
gas  was  dissipated  in  its  passage  from  the  producer  to  the  furnace,  which  was 
usually  placed  at  a  considerable  distance. 

Modern  practice  has  improved  on  this  early  plan,  by  introducing  steam  with 
the  air  that  is  blown  into  the  producer,  and  by  utilizing  the  sensible  heat  of  the  gas 
in  the  combustion  furnace.  One  pound  of  carbon,  burned  to  2.33  Ibs.  of  carbon  mon- 
oxide, CO,  develops  4400  heat  units,  or  about  30%  of  the  total  carbon  energy;  in 
the  secondary  combustion,  2.33  Ibs.  of  carbon  monoxide  burned  to  3.66  Ibs.  of 
carbon  dioxide  develop  10,100  heat  units,  or  70%  of  the  total  energy;  making  in  all 
14,500  heat  units  for  the  complete  combustion  of  the  original  pound  of  carbon.  Now, 
it  is  evident  that  if  the  heat  of  the  primary  combustion  is  not  employed  either  to 
dissociate  water  or  to  impart  a  useful  high  temperature  to  the  gas  30%}  of  the  energy 
will  be  practically  lost,  i.e.,  the  gas  will  carry  into  the  furnace  only  70%  of  the  total 
energy  of  the  carbon.  It  is  equally  evident  that  if  all  the  heat  of  primary  com- 
bustion could  be  applied  to  the  dissociation  of  water,  there  would  be  little  effective 
loss  of  energy  in  conversion;  or  if,  instead  of  dissociating  water,  all  the  sensible  heat 
of  the  gas  (representing  the  heat  of  primary  combustion)  could  be  utilized,  the  loss 
would  similarly  be  reduced  to  nil.  But  the  complete  realization  of  either  alternative 
is  impossible,  for  the  loss  by  radiation  from  the  producer  is  an  important  item,  and 
the  unrecovered  energy  expended  in  blowing  the  producer  with  air  and  steam  amounts 
to  from  3  to  5  per  cent. 

Good  practice  does,  however,  recover  a  considerable  percentage  of  the  heat  of 
primary  combustion  by  the  use  of  both  of  these  means,  i.e.,  by  utilizing  the  sensible 
heat  of  the  gas  through  close  attachment  of  producer  and  furnace,  and  by  intro- 
ducing with  the  air  blast  as  much  steam  as  the  producer  will  carry  and  still  maintain 
good  incandescence.  In  this  way  about  60%,  of  the  energy  of  primary  combustion 
should  be  theoretically  recovered,  for  it  ought  to  be  possible  to  oxidize  one  out  of 
every  4  Ibs.  of  carbon  with  oxygen  derived  from  water  vapor.  The  thermic  reactions 
in  this  operation  are  as  follows: 

Heat  Units. 

4  pounds  C  burned  to  CO  (3  Ibs.  gasified  with  O  of  air  and  1  Ib.  with  O  of  water)  develop.  .  .  .  17,600 
1.5  pounds  of  water  (which  furnish  1.33  Ibs.  of  oxygen  to  combine  with  1  Ib.  of  carbon)  absorb 

by  dissociation 10,333 

The  gas  consisting  of  9.333  Ibs.  CO,  0.167  Ib.  H,  and  13.39  Ibs.  H,  heated  600°,  absorbs 3,748 

Leaving  for  radiation  and  loss 3,519 


17,600 

(It  may  be  well  to  note  here  that  the  steam  which  is  blown  into  a  producer 
with  the  air  is  almost  all  condensed  into  finely  divided  water,  before  entering  the 
fuel,  and  consequently  is  considered  as  water  in  these  calculations). 

The  1.5  Ibs.  of  water  liberates  0.167  Ib.  of  hydrogen,  which  is  delivered  to  the 
gas,  and  yields  in  combustion  the  same  heat  that  it  absorbs  in  the  producer  by 
dissociation.  According  to  this  calculation,  therefore,  60%  of  the  heat  of  primary 
combustion  is  theoretically  recovered  by  the  dissociation  of  steam,  and  even  if  all 
the  sensible  heat  of  the  gas  with  radiation  and  other  minor  items  be  counted  as  loss, 
yet  the  gas  must  carry  4X14,500 -(3748+3519)  =50,733  heat  units,  or  87%  of  the 
calorific  energy  of  the  carbon.  This  estimate  shows  a  loss  in  conversion  of  13%, 


290 


GAS   PRODUCERS 


without  crediting  the  gas  with  its  sensible  heat,  or  charging  it  with  the  heat  required 
for  generating  the  necessary  steam,  or  taking  into  account  the  loss  due  to  burning 
some  of  the  carbon  to  carbon  dioxide.  In  good  producer  practice  the  proportion 
of  carbon  dioxide  in  the  gas  represents  from  4  to  7  per  cent  of  the  C  burned  to  C02, 
but  the  extra  heat  of  this  combustion  should  be  largely  recovered  in  the  dissocia- 
tion of  more  water  vapor,  and  therefore  does  not  represent  as  much  loss  as  it  would 
indicate.  As  a  conveyor  of  energy,  this  gas  has  the  advantage  of  carrying  4.46  Ibs. 
less  nitrogen  than  would  be  present  if  the  fourth  pound  of  coal  was  gasified  with  air; 
and  in  practical  working  the  use  of  steam  reduces  the  amount  of  clinkering  in  the 
producer. 

In  a  paper  read  by  W.  K.  Eavenson  before  the  second  annual  meeting  of  the 
American  Gas  Institute  the  subject  of  air-blast  gas  appliances  was  ably  treated.  He 
referred  to  burners  as  follows: 

Air  Injector. — In  the  different  types  of  burners  to  be  described,  used  with 
Philadelphia  city  gas,  the  gas  and  air  are  mixed  by  an  injector.  The  air  nozzle  is 


'  X  l"  REDUCER J 

I  I 


FIG.  129.— Blast  Connection  for  Furnaces. 

soldered  on  the  service  ell  A  and  extends  in  the  tee  B,  slightly  beyond  the  center 
line  of  the  side  outlet,  carrying  the  air  past  the  gas  way,  the  air  creating  a  slight 
suction  on  the  gas  line.  The  air  and  gas  are  mixed  in  the  pipe  C  on  the  way  to  the 
burner.  The  air  nozzle  is  made  of  tin  and  can  easily  be  replaced  by  another  of 
different  diameter,  if  adjustment  is  needed.  Satisfactory  results  cannot  be  obtained 
by  attempting  to  ram  or  contract  the  nozzle.  The  air  nozzle  should  be  so  adjusted 
as  to  derive  the  full  benefit  of  the  injector  effect.  For  instance,  after  the  fire-brick 
linings  have  become  sufficiently  heated  to  bring  a  furnace  to  its  maximum  heat, 
when  the  lever-handle  air  cock  is  wide  open,  a  reducing  or  gas  flame  should  issue 
from  the  furnace  vent.  The  pressure  in  the  gas  pipe  need  not  be  more  than  twenty- 
tenths. 


INDUSTRIAL   GAS  APPLICATIONS 


291 


Forms  of  Burners. — Some  types  of  burners  used  are  described  below.  In  these 
burners  no  outside  or  secondary  air  is  required  for  complete  combustion,  and,  as  a 
rule,  any  furnace  will  give  better  results  if  it  is  closed  tight  at  the  bottom. 

One  of  the  eight  burners  used  in  the  No.  1  oven  furnace  illustrates  the  general 
method  of  putting  blast  burners  in  oven  furnaces  having  a  fire-brick  lining,  into 
which  the  burners  are  inserted.  This  recessing  of  the  burners  serves  the  double 


FIG.  130. — Burner  Used  in  Oven  Furnace. 

purpose  of  protecting  it  from  the  heat,  and  also  of  maintaining  the  flame,  as  it  has 
been  found  that  this  type  of  burner  cannot  be  kept  lit,  if  in  the  open.  One  of  the 
most  interesting  features  of  the  use  of  gas  with  air  pressure  is  the  devices  that  are 
used  under  different  conditions  for  the  purpose  of  keeping  the  flame  lit. 

In  the  burner  shown,  attention  is  called  to  the  small  radiating  orifices  A,  which 
surround  the  main  burner  opening  B.  Without  these  orifices,  the  main  flame  would 
blow  out,  and  even  with  the  orifices,  the  flame  is  maintained  only  when  the  end  of 
the  burner  is  surrounded  by  a  projecting  hood  like  the  fire-brick  shown.  Why  the 
orifices  and  projecting  hood  act  as  they  do  is  a  matter  of  theory.  Probably  the  small 
size  of  the  tubes  and  the  fact  that  the  mixed  air  and  gas  issuing  from  them  impinge 
on  the  hood,  so  reduce  the  speed  at  the  point  of  combustion  that  there  is  less 
tendency  to  blow  out.  Then,  too,  the  walls  of  the  projecting  hood,  protect  the 
tender  flames  from  side  drafts. 


292 


GAS   PRODUCERS 


The  gas  and  air  mixture  can  be  kept  lighted,  when  it  issues  from  one  central 
opening  at  the  burner  nozzle,  provided  the  flame  plays  against  a  fire-brick  or  other 
surface,  located  close  in  front  of  the  nozzle;  but  it  is  not  as  certain  to  stay  lighted 
as  the  construction  described  above.  Also,  in  some  circular  furnaces,  burners  of 
simple  nozzles  are  used,  by  arranging  two  or  more  burners  around  the  circumference, 
so  set  at  a  tangent,  that  the  flames  play  around  the  circular  wall  in  the  same  direction 
and  thus  tend  to  keep  each  other  lighted. 

Ferrofix  Brazing  Head. — The  construction  of  this  burner  permits  of  keeping 
the  burner  lit  in  the  open.  The  principles  are  the  same  as  in  the  former  burner. 


GMJGE   .052 
DRILL  NO.  35 


GAUGE   .052" 
DRILL  No.  55 


FIG.  131. — The  Ferrofix  Brazing  Head  and  Machlet  Burner  Tip. 


The  secondary  flame  issues  from  the  annular  slit  A,  instead  of  from  small  orifices, 
and  the  projecting  hood  is  the  wrought-iron  pipe  B  instead  of  fire-brick. 

When  using  the  "  Ferrofix  "  head  in  constructing  home-made  brazing  furnaces, 
it  was  found  that  the  head  burned  out  very  quickly.  To  overcome  this,  it  was  pro- 
tected from  the  heat  by  cold-driving  it  in  a  cast-iron  collar.  This  collar  is  3  ins.  long 
and  ^  in.  thick.  The  face  of  the  wrought-iron  hood  B  is  recessed  I  in.  in  the  collar. 


INDUSTRIAL   GAS   APPLICATIONS 


293 


When  fitting  a  collar  to  a  head,  care  must  be  taken  not  to  close  the  circular  space  A. 
The  Ferrofix  head  has  been  put  to  the  following  uses: 

Home-made  cylindrical  brazing  furnaces  equipped  with  five  heads  (the  pro- 
tectors) are  being  used  for  brazing  flanges  on  the  large  copper  steam  pipes  of  locomo- 
tives. They  also  used  one  head  in  a  small  furnace  for  the  smaller  copper  pipes. 

Two  heads  were  placed  under  the  vaporizing  cap  of  a  125-h.p.  Hornsby-Akroyd 
oil  engine.  The  cap  must  be  heated  to  a  dark  red  before  the  engine  can  be  started. 
The  two  burners  enable  the  consumer  to  start  the  engine  in  15  minutes.  Ten  sets 
of  these  burners  were  installed  for  this  purpose.  These  burners  replace  the  oil 
lamps  originally  furnished  by  the  engine  manufacturers. 


„  N  \   . 

1    GLOBE  VALVE  H    UN 


„ 

IV  FLOOR  FLANGE  _.l*£| 


FIG.  132. — Special  Brazing  Burner. 

Three  heads  were  put  in  the  fire-oox  of  an  old  charcoal  brazing  furnace.  It  is 
used  for  brazing  the  bottoms  in  copper  pans  of  all  sizes.  Two  heads  were  adapted 
to  braze  the  joints  in  ice-cream  cans.  The  next  illustration  of  special  brazing 
burner  shows  the  Ferrofix  hSad  adapted  to  braze  the  copper  cylinders  of  chemical 
engines.  They  used  four  heads  here  as  some  of  the  cylinders  are  made  of  \  in.  copper, 
and  a  large  volume  of  flame  is  needed.  They  also  put  a  ring  of  heads  around  a  very 
large  cauldron  previously  heated  by  steam.  This  cauldron  is  used  for  manufactur- 
ing axle  grease. 

Machlet  Burner. — The  construction  permits  of  keeping  the  bruner  lit  in  the 
open.  The  principle  of  maintaining  the  flame  of  the  burner  is  similar  to  that  used 
with  the  Ferrofix  head.  The  ribbons  A  are  recessed  £  in.  in  the  shell  B.  This 
prevents  the  draft  of  air  from  blowing  or  sucking  out  the  small  flames  which  burn 


294 


GAS   PRODUCERS 


from  the  ports  C  and  D.  The  pressure  of  the  gas  and  air  is  probably  sufficiently  cut 
(due  to  its  impinging  on  the  part  E)  to  hold  the  flame  to  the  burner.  With  this 
burner  it  appears  that  the  small  flames  burning  at  D  act  as  pilots  to  the  flames 
burning  at  C. 

The  tips  are  made  of  one  size,  f  in.  diameter,  and  can  be  set  in  rows  in  pipe  burners 
of  straight  or  circular  form,  or  arranged  in  clusters,  etc.  In  Philadelphia  they  have 
used  the  Machlet  tip  in  the  following  home-made  appliances:  In  japanning  ovens 
for  enameling  the  frames  of  baby  carriages  and  velocipedes  and  skylight  frames. 
Under  tinning  furnaces  and  sawdust  driers. 

Singeing  Burner. — The  feature  of  the  ribbon  burner  is  that  it  gives  from  end  to 
end  a  continuous  line  of  flame  of  uniform  size,  thus  rendering  it  useful  for  such 


FIG.  133. — Ribbon  Singeing  Burner: 

purposes  as  singeing  fabrics,  and  roasting  coffee,  where  a  line  of  separate  burners^ 
with  spaces  between  the  flames  would  not  answer. 

The  ribbon  burner  has  been  utilized  as  follows:  Under  the  6-foot  cylinder  of  an 
old  coffee  roasting  machine,  the  capacity  of  the  cylinder  being  350  Ibs.  Two  ribbons 
were  set  in  a  pipe  paralleling  the  cylinder,  so  that  the  two  lines  of  flames  impinged 
on  the  cylinder  at  an  angle  to  each  other.  One  of  their  customers  was  using  a 
machine  of  German  manufacture  for  singeing  tapestry.  The  gas  flame  issued  from 
a  slot  about  4  ft.  long,  the  slot  being  formed  by  two  bevel-edged  plates  which  could 
be  adjusted  and  held  by  set-screws.  The  flame  was  uneven  and  at  places  inter- 
mittent. To  overcome  this  trouble  one  of  the  ribbons  was  taken  out  of  a  ribbon  burner 
and  set  it  in  the  slot,  holding  it  by  squeezing  it  between  the  beveled  plates.  The 
result  was  a  steady,  even  flame  which  produced  satisfactory  results. 

Soft  Metal  Burner. — Still  another  burner  is  the  soft-metal  burner.  With  this 
burner  an  intense  heat  can  be  maintained  under  cauldrons  for  melting  metal,  candy, 
etc.  The  illustration  shows  one  of  the  sixteen  stoves  of  their  own  design  sold  to 
a  consumer.  It  gives  quicker  results  than  any  stove  treating  40  Ib.  batches 
of  candy  in  15  minutes,  instead  of  30  for  the  stove  replaced.  The  stove  is  equipped 
•with  the  No.  6  soft-metal  burner.  The  construction  of  the  burner  permits  of  its 
being  lit  in  the  open.  The  bottoms  of  the  pans  come  within  8  ins.  of  the  top  of  the 
plug  C.  A  half-inch  sheet-iron  flare  prevents  the  flame  from  touching  the  pan 
above  the  level  of  the  syrup,  thus  preventing  scorching. 


INDUSTRIAL   GAS    APPLICATIONS 


295 


The  sight  holes  G  are  used  to  determine  the  condition  of  the  flame  when  the  pan 
is  in  place.  When  the  stoves  are  not  in  use,  the  burners  are  protected  from  the 
dust  peculiar  to  a  candy  shop,  by  sheet-iron  caps. 

An  old  charcoal  furnace,  used  for  tinning  objects  and  for  annealing  copper  pans, 
was  equipped  with  this  burner.  This  burner  was  also  used  under  pots  of  old  coal 
furnaces,  for  melting  metal,  under  potash  kettles,  under  kettles  for  supplying  hot 
water,  and  in  the  frames  of  old  coal  candy  furnaces. 


L_ 


FIG.  134. — Blast  Confectionery  Stove. 

Blow  Torch. — The  brazing  torch  is  a  type  of  burner  oa  the  market  which  is 
useful  for  certain  purposes.  It  will  stay  lit  in  the  open,  apparently  because  the  gas 
and  air  mixture  is  burned  at  a  point  close  to  the  injector.  As  already  described,  if 
the  mixture  is  piped  any  distance  from  the  injector,  one  of  the  several  special  types 
of  burners,  as  described,  must  be  used  in  order  to  maintain  the  flame. 

This  torch  was  used  in  a  glass-bending  furnace.     The  flat  pieces  of  glass  are  placed 


296 


GAS   PRODUCERS 


on  the  molds  which  set  in  the  furnace  on  a  slab.     The  heat  is  then  applied  through 
the  torch  held  in  the  hand  of  the  operator  until  the  glass  forms  to  the  mold.     It  is 


Innn 
".'jam 


FIG.  135.— Blast  Blew  Torch. 


SINGLE    BURNER. 


DOUBLE    BURNER. 


TRIPLE   BURNER. 


FIG.  136. — Cyclone  Annular  Burner. 

then  removed  and  placed  in  an  annealing  oven  to  cool.  The  molds  vary  in  size, 
the  largest  one  being  14  by  24  ins.  To  take  care  of  the  large  molds,  the  end 
of  one  of  the  torches  had  to  be  flattened  out  to  a  2-inch  oblong  opening,  thus  enabling 


INDUSTRIAL   GAS    APPLICATIONS 


297 


the  operator  to  cover  the  mold  with  a  solid  sheet  of  flame.  The  flame  must  cover 
the  mold,  otherwise  the  glass  will  break. 

These  industrial  burners  are  applied  to  many  purposes  and  are  a  durable 
and  efficient  type.  They  are  designed  to  intensify  flame  propagation  and  are  especially 
effective  with  gases  having  high  ignition  points. 

Pressure  Blowers. — Because  burners  utilizing  producer  gas  must  be  operated 
under  pressure,  both  gas  and  air  blowers  are  necessary,  a  separate  one  for  each, 
since  they  must  be  kept  separate  until  they  mix  at  the  burner.  The  gas  should 
be  delivered  under  a  slightly  lower  pressure  than  the  air  to  secure  the  best  results 


FIG.  137. — Pressure  Blower  for  Gas. 


and  the  exact  regulation  is  possible  by  having  two  blowers.  The  gas  booster  is  of 
somewhat  different  construction  from  the  air  blower.  The  American  Gas  Furnace 
Co.  make  a  gas  blower  running  at  25  r.p.m.  and  delivering  gas  under  a  pressure  of 
0.5  to  2  Ibs.  pressure  per  square  inch.  The  one  here  illustrated  has  a  pulley  8  ins. 
diameter  and  2  ins.  face.  The  pressure  is  regulated  by  the  weights  above  the  dis- 
charge pipe;  no  weight  delivers  ^  Ib.  and  each  weight  added  increases  the  pressure 
by  i  Ib. 

Forge  Work. — Small  furnaces  for  this  industry  have  been  operated  for  some 
time  on  fuel  oil  or  gases  more  expensive  than  ordinary  producer  gas.  Because  of 
its  lower  heating  value  and  consequently  necessary  large  volume,  the  application  of 
producer  gas  requires  special  treatment.  The  system  is,  however,  in  successful 
service,  giving  good,  quick  forging  heats,  with  large  economy  over  oil  or  other  methods 
of  firing,  and  with  absence  of  the  smoke  and  dirt  of  ordinary  coal  fires.  The  gas 


298 


GAS    PRODUCERS 


serves  heating  furnaces  for  bending,  heading,  bolt  and  rivet  machines  and  a  variety 
of  miscellaneous  work.  In  such  installations,  however,  it  is  best  to  concentrate  the 
furnaces  as  much  as  possible.  It  is  difficult  and  often  impracticable  to  pipe  the  gas 
to  scattered  furnaces  at  great  distances  from  each  other.  With  properly  designed 
flues  and  connections,  the  soot  can  be  cared  for  without  trouble. 


FIG.  138.— Muffle  Furnace  Using  City  Gas. 

With  holder  pressure,  a  temperature  of  2000°  F.   was  obtained,   which  was  raised   to   2500°  F.  by 

blast  from  an  attached  fan. 


The  furnace  hearths  may  be  as  small  as  6X12  ins.  or  as  large  as  desired.  They 
may  be  so  designed  for  the  particular  class  of  work  they  do  that  the  heat  will  be  well 
centered  on  the  iron  being  heated,  and  are  therefore  economical  in  fuel.  For  obtain- 
ing welding  heats  reversing  regenerative  furnaces  must  be  used,  giving  the  best  weld- 
ing heats  obtainable.  One  furnace  will  readily  supply  four  to  six  men  with  work, 
so  that  considering  the  amount  of  work  heated  the  cost  of  the  furnace  is  low.  The 
type  of  furnace  and  the  character  of  the  gas  best  suited  to  any  case  can  be  determined 
only  by  a  study  of  the  conditions  of  each  installation. 

Various  Applications. — The  accompanying  illustrations  show  a  large  variety 
of  uses  to  which  gas  heating  is  applied. 


INDUSTRIAL  GAS   APPLICATIONS 


299 


FIG.  139.— Water 

Still. 


FIG.  140. — Producer  Gas  Heating  Furnace  for  Heating  Plates  for 
Pressing  into  Shapes. 


FIG.  141. — Brazing  by  Producer  Gas. 


300 


GAS   PRODUCERS 


FIG.  142. — Producer  Gas-fired  Crucible  Furnaces  for  Heating  Brass  and  Aluminum. 
Capacity,  9  melts  per  10  hours. 


FIG.  143. — Producer  Gas  Forge  Furnace.     Heats  14,500  £-inch  bolts  in  10  hrs. 


INDUSTRIAL  GAS   APPLICATIONS 


301 


FIG.  144. — Producer  Gas-fired  Furnaces.    Case  Hardening,  Annealing  and  Core  Ovens. 


FIG.  145. — Large  Producer  Gas-fired  Furnace  for  Heating  Steel  Ingots  up  to  5000  Ibs.      There  is  no 
flue  for  waste  gases  and  the  temperature  is  about  3000°  F. 


302 


GAS   PRODUCERS 


FIG.  146. — Galvanizing  with  Producer  Gas  Heat. 


FIG.  147. — Producer  Gas-fired  Annealing  Ovens.     Built  for  natural  gas  but  changed 

over  to  producer  gas. 


INDUSTRIAL   GAS   APPLICATIONS 


303 


FIG.    148. — Producer  Gas-heated  Japanning  Ovens  Used  on  Sewing  Machine  Heads.     They   are 
heated  to  500°  F.  in  20  minutes.     Natural  gas  had  been  used  previously. 


Gas  Firing  of  Steam  Boilers. — The  Kirkwood  burner  and  mixer  has  proved 
one  of  the  most  successful  in  the  natural  gas  fields  and  has  also  been  extensively  used 
in  the  firing  of  cement  kilns  with  gas;  the  action  of  the  burner  secures  an  especially 
good  mix.  The  best  results  are  obtained  from  the  use  of  any  burner  by  applying  the 
flame  to  the  water  leg  of  the  boiler  at  an  angle  of  45°.  With  natural  gas  the  first 
half  of  the  flame  should  be  a  decided  green,  changing  to  blue.  A  cherry  streak  in  the 
flame  is  not  objectionable,  but  any  yellow  color  should  not  be  permitted.  A  burner 
designed  to  throw  a  flat  jet  of  flame  say  10  ins.  wide  at  an  angle  of  45°  against  a  water 
leg  will  be  found  particularly  efficient. 

The  gas  should  be  supplied  with  plenty  of  force,  and  where  this  is  not  otherwise 
available,  can  be  furnished  through  the  medium  of  an  inductor  operated  by  air  under 
pressure.  This  pressure  may  safely  run  from  1  to  1.5  Ibs.  Where  small  water  heating 
boilers  are  used,  burners  of  the  Cyclone  type,  the  invention  of  Henry  L.  Doherty, 
designed  to  secure  rapid  flame  propagation  through  the  return  of  flame  to  the  point  of 
ignition,  will  be  found  very  satisfactory.  Producer  and  natural  gas  fire-brick  gratings, 
in.  connection  with  a  gas  mixture  chamber  will  be  found  good.  The  nipples  from 
valves  to  burners  which  constitute  the  mixing  valve  in  small  burners  should  not  be 
less  than  8  ins.,  as  the  lesser  length  creates  a  liability  to  back  firing  or  flashing. 
Ordinarily  burners  should  be  located  from  1  to  2  ins.  from  the  water  leg  of  the  boiler 
unless  annular  burners,  or  burners  of  the  perforated  pipe  type,  are  used,  which  would 
not  be  located  less  than  3  ins.  from  the  water  leg.  This  is  for  the  reason  that  the 
flame  from  annular  burners  cannot  be  impinged  at  an  angle  and  there  is  a  tendency 
for  the  flame  to  reverberate  and  striking  the  fire  surface  reflect  back  upon  the  burner. 
This  should  at  all  times  be  prevented. 


304 


GAS   PRODUCERS 


FJG.  149. — Kirkwood  Natural  Gas  Burner. 


INDUSTRIAL   GAS    APPLICATIONS 


305 


As    in     ordinary     boilers,     sheet     iron     dampers     should     be     used     and     the 
damper    so    adjusted   as    to    allow    only    enough    to    escape    through    the    flue    to 


FIG.  150. — Position  of  Burner  and  Fire-wall  in  Furnace. 

carry    off    the   products    of    combustion.       The    flame    is   usually   so    regulated   as 
to  travel  as   far  as  possible  along  the  sections  of  the  boiler. 

It  is  claimed  by  some  engineers  that 
the  best  practice  is  to  direct  the  flame 
into  a  network  of  fire-brick,  so  that  it  is 
thoroughly  diffused  and  spread  before 
coming  into  contact  with  the  heating 
surface  of  the  boiler,  rather  than  to  allow 
the  flame  from  the  several  burners  within 
the  furnace  to  impinge  directly  against 
any  part  of  the  heating  surface,  which 
might  in  that  way  cause  damage  by  reason 
of  inequality  of  temperatures.  The  gas 


m 


Section  Of  CThtcktr  WoJI 
l«Quol  fUBr.cli  \li* 


FIG.  151— Front  of  Fire-wall. 


FIG.  152. — Kirkwood  Burners  Applied  to  Water- 
tube  Boilers  without  Disturbing  the  Stoker. 


is  impinged  into  a  lattice  or  checker-work  pen,  built  up  of  fire-brick.     The  interstices 
(made  by  use  of  "  soaps  "  or  half  brick),  regulating  the  intimacy  of  the  mixture. 


306 


GAS   PRODUCERS 


FIG.  153.— Gas-fired  Water  Tube  Boiler. 

9 


FIG.  154. — Another  Gas-fired  Water  Tube  Boiler. 


FIG.  155. — The  Sipp  Gas-fired  Steam  Boiler. 


INDUSTRIAL   GAS   APPLICATIONS  307 

The  use  of  producer  gas-firing  of  boilers  is  only  to  be  advocated  under  conditions 
of  low  grade  fuels,  with  particular  reference  to  lignites.  With  this  character  of  coal 
the  efficiency  of  direct  firing  is  largely  reduced  in  the  average  type  of  boiler  by  the 
loss  of  a  portion  of  the  high  volatile  matter.  This  gas  escapes  from  the  combustion 
zone  more  rapidly  than  it  is  consumed,  that  is  to  say,  it  passes  the  ignition  area  prior 
to  its  ignition. 

The  flame  propagation  of  lignite  is  so  rapid  as  to  make  its  direct  firing  by  hand 
a  matter  of  extreme  difficulty.  Moreover  its  tendency  to  "  fine  "  makes  close  grates 
impractical,  while  in  using  wider  grates  or  voids  the  grate  loss  is  materially  increased. 
With  coal  of  this  character  it  is  therefore  economical  to  use  two-stage  combustion  and 
gasify  it  prior  to  its  admission  into  the  combustion  chamber. 

Boilers  Using  Waste  Gases. — The  proportioning  of  boilers  for  blast  furnaces 
is  discussed  as  follows  by  Kent,  who  says  that  Mr.  Gordon's  recommendation  for 
proportioning  boilers  when  properly  set  for  blast  furnace  gas  is,  for  coke  practice,  30 
sq.ft.  of  heating  surface  per  ton  of  iron  per  24  hours,  which  the  furnace  is  expected 
to  make,  calculating  the  heating  surface  thus:  For  double  fined  boilers,  all  shell 
surface  exposed  to  the  gases,  and  half  the  flue  surface;  for  the  French  type  all  the 
exposed  surface  of  the  upper  boiler  and  half  the  lower  boiler  surface;  for  cylindrical 
boilers  not  more  than  60  ft.  long  all  the  heating  surface.  To  the  above  must  be  added 
a  battery  for  relay  in  case  of  cleaning,  repairs,  etc.,  and  more  than  one  battery  extra 
in  large  plants,  when  the  water  carries  much  lime.  For  anthracite  practice  add  50% 
to  above  calculations.  For  charcoal  practice  deduct  20%. 

In  a  letter  to  the  author  in  May,  1894,  Mr.  Gordon  says  that  the  blast  furnace 
practice  at  the  time  when  his  article  (from  which  the  above  extract  is  taken)  was 
written  was  very  different  from  that  existing  at  the  present  time;  besides,  more 
economical  engines  are  being  introduced,  so  that  less  than  30  sq.ft.  of  boiler  surface 
per  ton  of  iron  made  in  24  hours  may  now  be  adopted.  He  says  further:  Blast  furnace 
gases  are  seldom  used  for  other  than  fuel  requirements,  which  of  course  is  throwing 
away  good  fuel.  In  this  case  in  a  furnace  in  ordinary  good  condition,  and  a  condi- 
tion where  it  can  take  its  maximum  of  blast,  which  is  in  the  neighborhood  of  200  to 
225  cu.ft.  atmospheric  measurement  per  sq.ft.  of  sectional  area  of  hearth,  will  generate 
the  necessary  horsepower  with  very  small  heating  surface  owing  to  the  high  degree 
of  the  escaping  gases  from  the  boilers  which  is  frequently  1000°. 

A  furnace  making  200  tons  of  iron  per  day  will  consume  about  900  h.p.  in  blowing 
the  engine.  About  a  pound  of  fuel  is  required  in  the  furnace  per  pound  of  pig  metal. 

In  practice  it  requires  70  cu.ft.  of  air  piston  displacement  per  pound  of  fuel 
consumed  or  22,400  cu.ft.  per  minute  for  200  tons  of  metal  in  1400  working  minutes 
per  day  at  say  10  Ibs.  discharge  pressure.  This  is  equal  to  Q\  Ibs.  m.e.p.  on  the  steam 
piston  of  equal  area  to  the  blast  piston  or  900  i.h.p.  To  this  add  20%  for  hoisting, 
pumping  and  other  purposes  for  which  steam  is  employed  around  blast  furnaces,  and 
we  have  1100  h.p.  or  say  5^  h.p.  per  ton  of  iron  per  day.  Dividing  this  into  30  gives 
approximately  5^  sq.ft.  of  heating  surface  of  boiler  per  horsepower. 

Water  tube  boilers  using  blast  furnace  gases  are  described  by  D.  S.  Jocobus  (Trans. 
A.  I.  M.  E.,  xvii,  50)  who  reports  a  test  of  a  water-tube  boiler  using  blast  furnace  gas 
as  fuel.  The  heating  surface  was  2535  sq.ft.  It  developed  328  h.p.  (Centennial 
standard)  or  5.01  Ibs.,  of  water  from  and  at  212°  per  square  foot  of  heating  surface 


308 


GAS    PRODUCERS 


per  hour.  Some  of  the  principal  data  obtained  were  as  follows:  Calorific  value  of 
1  Ib.  of  the  gas  1413  B.T.tl.  including  the  effect  of  its  initial  temperature,  which  was 
650°  F.  Amount  of  air  used  to  burn  1  Ib.  of  the  gas  equals  0.9  Ib.,  chimney  draught 
1J  ins.  of  water.  Area  of  gas  inlet  300  sq.ins.;  of  air  inlet  100  sq.in.  Temperature 
of  the  chimney  gases  775°.  Efficiency  of  the  boiler  calculated  from  the  temperatures 
and  analyses  of  the  gases  at  exit  and  entrance  61%.  The  average  analyses  were  as 
follows,  hydrocarbons  being  included  in  the  nitrogens. 


Blast  Furnace  Gas 

By  Weight. 

By  Volume. 

At  Entrance. 

At  Exit. 

At  Entrance. 

At  Exit. 

CO,  . 

10.69 
.11 
26.71 
62.48 
2.92 
11.45 
14.37 

26.37 
3.05 
1.78 
68.80 
7.19 
.76 
7.95 

7.08 
.10 
27.80 
65.02 

18.64 
2.96     . 
1.98 
76.42 

o             

CO  

Nitrogen  ...        

C  in  CO, 

C  in  CO 

Total  C 

Steam  Boilers  Fired  with  Waste  Gases  from  Puddling  and  Heating  Furnaces.  — 
The  Iron  Age  (April  6th,  1893)  contains  a  report  of  a  number  of  tests  of  steam  boilers 
utilizing  the  waste  heat  from  puddling  and  heating  furnaces  in  rolling  mills.  The 
following  principal  data  are  selected.  In  Nos.  1,  2  and  4  the  boiler  is  a  Babcock  and 
Wilcox  water  tube  boiler,  and  in  No.  3  is  a  plain  cylinder  boiler  42  ins.  diameter  and 
26  ft.  long.  No.  4  boiler  was  connected  with  a  heating  furnace,  the  others  with 
puddling  furnaces. 


No.  1. 

No.  2. 

No.  3. 

No.  4. 

Heating  surface   sq  ft                     

1026 

1196 

143 

1380 

Grate  surface  sq  ft                            

19.9 

13.6 

13.6 

16.7 

Ratio  heating  surface  to  grate  surface  

52 

87.2 

10.5 

82.8 

Water  evaporated  per  hour,  Ibs  

3358 

2159 

1812 

3055 

\Vater  evaporated  per  sn  ft   Ibs  per  hour  Ibs 

3.3 

1.8 

12  7 

2  2 

\Vater  evaporated  per  Ib  coal  from  and  at  212° 

5  9 

6  24 

3  76 

6  34 

\Vater  evaporated  per  Ib  fuel  from  and  at  212° 

7.20 

4.31 

8  34 

In  No.  2  1.38  Ibs.  of  iron  were  puddled  per  Ib.  of  coal. 

In  No.  3  1.14  Ibs.  of  iron  wrere  puddled  per  Ib.  of  coal. 

No.  3  shows  that  an  insufficient  amount  of  heating  surface  was  provided  for  the 
amount  of  waste  heat  available. 

Gas  Firing,  Rust  Boiler. — An  arrangement  is  here  illustrated  for  the  firing  of 
a  Rust  water-tube  boiler  by  means  of  blast  or  producer  gas,  the  gas  being  admitted 
through  an  over  head  flue,  and  there  being  no  anticipation  of  burning  coal.  The 
burners  enter  the  front  above  the  fire  door  so  that,  should  it  be  desired,  the  usual 
grates  and  accessories  may  be  supplied  and  the  boilers  fired  with  coal  in  addition,  or 
by  coal  or  gas  interchangeably. 


INDUSTRIAL  GAS   APPLICATIONS 


309 


310  GAS   PRODUCERS 

Natural  gas  burners  may  be  used  for  firing  these  boilers  if  sufficiently  large',  in 
which  case  there  should  be  considerable  additional  area  by  reason  of  this  latter  heat 
value.  In  firing  with  natural  gas  a  much  larger  volume  of  air  per  cubic  foot  of  gas 
may  be  prepared  for. 

In  using  producer  gas  or  blast  gas  some  advantage  in  reverberation  and  combustion 
is  obtained  by  impingeing  the  gases  on  or  into  checker  brick-work.  The  former  being 
particularly  the  case  where  the  area  of  the  combustion  chamber  is  limited. 

With  low  value  gas  the  flame  should  never  be  allowed  to  impinge  upon  any 
portion  of  the  heating  surface  of  the  boiler.  This  is  for  the  reason  that  the  relatively 
low  temperature  due  to  water  cooling  tends  to  reduce  the  flame  temperature  of  certain 
portions  of  the  gas  below  the  point  of  igniiton  whence  it  escapes  unburned,  with 
considerable  consequent  loss.  Ample  time  and  space  should  be  allowed  for  complete 
combustion  of  the  gas  before  striking  these  surfaces.  In  an  installation,  such  as  that 
indicated  with  a  Rust  boiler,  7  or  8  ft.  should  be  allowed  between  the  gas  burner  and 
the  nearest  portion  of  the  heating  surfaces. 

Gas  Firing,  Lester  Boiler. — A  paper  by  ,1.  H.  Lester,  M.Sc.,  published  in  the 
Journal  Soc.  Chem.  Industry  (May  15,  1908)  describes  a  remarkable  experimental 
form  of  gas-heated  steam  boiler  which,  if  it  can  be  copied  on  a  large  scale,  will  be 
likely  to  revolutionize  the  present  methods  of  steam  generation. 

As  an  example  of  the  high  duty  obtainable  in  steam  production  with  this  form  of 
boiler,  Mr.  Lester  states  that  a  series  of  his  gas-heated  tubes  built  up  into  a  block 
occupying  only  1  cu.yd.  of  space,  would  evaporate  as  much  wrater  as  a  Lancashire 
boiler  measuring  30  ft.  by  8  ft.  diameter  and  that  the  efficiency  of  the  new  boiler 
would  be  as  high  as  that  of  the  Lancashire  boiler  when  worked  with  economizers. 

The  experimental  boiler  designed  by  Mr.  Lester  consisted  simply  of  a  copper 
tube  of  ^  in.  internal  diameter,  and  20  ins.  in  length,  surrounded  by  a  jacket  allow- 
ing i"g  in.  space  between  the  two  tubes. 

The  gas  and  air  mixture  entered  at  the  top  of  the  inner  tube,  and  by  careful 
regulation  a  flame  7  ins.  in  length,  showing  less  than  0.50%  of  free  oxygen,  and  less 
than  0.50%  of  carbon  monoxide  in  the  exit  gases,  could  be  obtained.  The  water 
entered  the  annular  space  between  the  two  tubes  and  flowed  upward  in  the  opposite 
direction  to  that  of  the  gas  mixture.  The  cooling  of  the  gas  by  the  adoption  of  this 
principle  of  counter-current  circulation  wras  so  effective  that  the  latent  heat  of 
condensation  of  the  water  produced  by  the  combustion  of  the  gas  was  recovered;  and 
the  total  loss  of  heat  at  the  base  (or  chimney  end)  of  the  combustion  tube  never 
exceeded  5%.  Mr.  Lester,  in  fact,  believes  that  by  lengthening  his  tubes  he  could 
recover  100%  of  the  calorific  value  of  the  gas  in  the  water,  and  thus  convert  his  boiler 
into  a  calorimeter. 

The  steam  passed  away  by  an  outlet  in  the  side  of  the  upper  part  of  the  outer 
tube.  The  restricted  space  available  for  water  \vas  purposely  adopted  in  order  to 
prevent  any  downward  current  of  water  in  the  annular  space. 

The  burning  of  the  gas  with  the  minimum  of  oxygen  supply,  of  course  increased 
the  final  temperature  attained  by  the  gas  mixture,  and  therefore  the  efficiency  of  the 
boiler.  It  was  found  experimentally,  that  the  production  of  a  rapid  series  of  gas 
explosions,  or  musical  notes,  appeared  to  be  coincident  with  the  conditions  required 
for  this  perfect  combustion,  and  that  the  mixture  giving  the  highest  musical  note 


•  INDUSTRIAL   GAS    APPLICATIONS  311 

when  ignited  gave  the  most  satisfactory  results  as  regarded  low  percentages  of  free 
oxygen  and  carbon  monoxide  in  the  exit  gases. 

A  boiler  constructed  upon  this  principle,  using  producer  gas,  might  therefore 
convert  95%  of  the  heating  value  of  the  gas  into  the  thermal  energy  of  steam;  and,  as 
Mr.  Lester  remarks,  the  construction  of  such  a  boiler  does  not  offer  insuperable  diffi- 
culties. 

The  theory  of  Mr.  Lester's  boiler  is  unquestionably  correct,  embodying  as  it  does 
the  well  known  principle  of  heat  absorption  from  reverse  currents. 

However,  it  has  certain  mechanical  difficulties  which  must  be  obviated.  Prin- 
cipally that  of  the  fact  that  the  hot  gases  come  in  contact  with  the  steam  heat  of  the 
boiler  instead  of  the  water  leg  and  it  will  be  difficult  for  the  tubes  to  resist  the  heat 
of  same,  there  being  no  water  cooling  to  protect  them. 

When  experiments  of  this  kind  have  been  tried  under  commercial  conditions,  it 
has  been  found  that  not  only  have  the  tubes  resisted  the  intense  heat  of  the  gas  very 
badly,  but  it  has  been  almost  impossible  to  keep  them  tight  within  the  tube  sheet. 


CHAPTER  XIII 
FURNACES  AND    KILNS 

THE  sensible  temperature  of  the  effluent  gases  from  a  pressure  producer  vary 
from  300  to  1500°  F.,  according  to  the  type  of  the  producer  and  the  nature  of  the 
fuel,  rarely  exceeding,  however,  1000°  F.  The  pressure  maintenance  upon  the  gas 
mains  varies  in  practice  from  practically  zero  up  to  4  ins.  of  water,  equivalent  to 
2.4  ounces. 

There  is,  of  course,  liability  of  explosion  in  such  an  application  as  to  a  gas-fired 
kiln,  but  there  being  practically  no  compression  the  resultant  damage  is  usually  trivial, 
and  the  danger  practically  confined  to  the  possible  scorching  of  attendants.  Even  this 
may  be  obviated  by  a  reasonable  degree  of  care  in  operation.  All  chances  of  asphyxia- 
tion must  also  be  guarded  against. 

There  are  conditions  for  which  the  continuous  kiln  is  not  adapted  and  in  such 
cases  unit  kilns  must  still  be  used.  A  scheme  that  has  given  good  results  in  Germany 
is  to  build  the  individual  fire  boxes  of  such  a  form  as  to  have  the  condition  of  gas 
firing,  i.e.,  have  a  thick  fuel  bed  and  admit  an  auxiliary  air  supply  over  and  above 
the  surface  of  the  fuel,  in  such  a  way  as  to  secure  a  mixture  of  the  air  and  gases  before 
the  latter  are  burned  in  the  combustion  chamber.  With  this  arrangement  it  is  possible 
to  secure  perfect  combustion — eliminating  the  smoke  nuisance — higher  temperatures 
and  better  conditions  in  the  kilns.  The  arrangement  is  simply  the  conversion  of  the 
usual  fire  box  into  a  small  gas  producer.  The  Christy  Fire  Clay  Company,  of  St. 
Louis,  has  introduced  this  method  on  some  of  its  unit  kilns  for  burning  fire-brick. 

Brick  burning  with  natural  gas,  has  reduced  the  length  of  the  operation  one-third, 
and  the  same  decrease  in  time  should  be  true  of  producer  gas  firing. 

The  German  practice  is  to  have  one  or  more  little  producers  built  into  each  kiln, 
but  the  American  system  of  centralizing  the  producer,  or  segregating  the  producers,  is 
much  more  efficient,  convenient,  and  economical  of  fuel,  the  latter  showing  in  some 
instances  a  saving  of  33^%. 

If  the  gas  is  to  be  used  in  ordinary  down-draft  kilns,  there  should  be  a  branch 
pipe  leading  into  each  of  the  fire-places  already  existing.  In  this  pipe  there  should 
be  a  valve  for  regulating  the  amount  of  gas  admitted.  Just  above  where  the  gas. 
enters,  the  air  for  supporting  the  combustion  must  be  admitted.  The  two  wili 
combine  behind  the  bag  wall  and  the  flame  go  up  over  into  the  combustion  chamber, 
just  as  it  does  with  the  ordinary  direct  coal  fire,  except  that  the  quality  of  the  flame 
would  be  .more  like  that  from  wood,  being  longer  and  softer  and  more  easily  diffused 
throughout  the  kiln  than  a  coal  flame.  At  the  same  time  any  desired  temperature 
can  be  obtained,  even  great  enough  to  melt  fire-brick. 

312 


FURNACES    AND    KILNS  313 

It  may  be  noted,  as  an  item  of  significant  importance,  that  the  majority  of  shaft 
or  vertical  kilns  have  not  been  particularly  economical  when  operated  by  producer 
gas,  as  compared  with  kilns  of  horizontal  type.  This  may  be  by  reason  of  the  rever- 
beratory  features  with  the  latter  type,  or  by  reason  of  the  increased  rate  in  the  flow 
of  gases  in  the  former  due  to  both  draft  and  convection,  or  it  may  be  due  to  a  combina- 
tion of  the  several  features  noted. 

Producer  Gas  Furnaces. — Producer  gas  being  so  low  in  caloric  energy,  cannot 
be  used  to  advantage  in  high-temperatrue  furnaces,  without  at  least  pre-heating  the 
air  for  combustion.  When  both  air  and  gas  are  properly  pre-heated,  as  in  the  best 
regenerative  furnaces,  a  very  high  economy  can  be  obtained,  and  only  a  half  or  a 
third  as  much  fuel  is  required  to  do  a  given  amount  of  work  as  when  the  coal  is  burned 
direct. 

The  essentials  for  the  economical  heating  of  a  high-temperature  furnace  are,  a  good 
quality  of  gas  (preferably  rich  in  hydrocarbons),  properly  mixed  with  just  the  right 
amount  of  air,  both  having  been  heated  to  as  high  a  temperature  as  possible.  The 
amount  of  air  required  is  dependent  upon  the  temperatures  of  gas  and  air.  The 
proper  mixing  of  the  gas  and  air  is  very  important.  To  obtain  the  best  results,  the 
mixture  should  be  as  rapid  and  intimate  as  possible,  thus  causing  a  high  temperature 
in  the  shortest  time  after  the  air  and  gas  come  together.  It  is  also  important  that  the 
furnace  should  be  of  the  proper  shape  and  proportions,  so  as  to  utilize  the  heat 
generated  to  the  best  advantage. 

The  modern  practice  of  heating  by  radiation  instead  of  by  contact  is  undoubtedly 
right;  hence  the  high  roof  of  the  so-called  regenerative  gas  furnaces,  and  the  large 
volume  of  luminous  gas  with  its  powerful  radiating  properties  over  the  bed  of  iron  or 
other  material  to  be  heated.  It  is  certainly  a  fact  that  we  require  a  very  much  greater 
volume  of  non-luminous  gas  than  we  do  of  luminous  gas  to  do  a  given  amount  of 
heating  at  high  temperatures. 

In  many  works  we  find  the  waste  heat  from  the  furnace  used  in  making  steam, 
and  this  plan  is  advocated  by  some  high  authorities.  But,  if  there  were  no  other 
objections  to  it,  the  waste  heat  from  the  furnace  heating  iron  for  instance,  would  be 
very  much  more  than  is  necessary  for  furnishing  the  power  to  roll  the  product.  For 
this  reason  alone  it  is  better  to  recover  the  waste  heat  and  return  it  to  the  furnace, 
generating  steam  in  a  separate  apparatus  as  required;  for  it  will  be  impossible  to 
arrange  any  works  so  as  to  utilize  all  the  waste  heat  direct  from  furnaces. 

Regenerative  furnaces  have  been  much  improved  of  late  years  by  making  the 
roofs  higher  and  working  on  the  radiating  principle.  Maximum  economies  can  only 
be  obtained  from  these  furnaces,  however,  by  running  them  continuously,  say  for  a 
week  at  a  time,  as  it  takes  a  large  expenditure  of  energy  to  heat  them  up  when  they 
are  once  allowed  to  cool. 

In  many  cases,  where  a  very  high  temperature  is  not  required,  producer  gas  can 
be  used  with  considerable  economy  over  direct  firing,  by  pre-heating  the  air  only,  up 
to  a  temperature  of  500°  or  600°  in  "  continuous  regenerators."  These  are  usually 
composed  of  iron  pipes,  through  which  the  air  is  blown  or  drawn,  and  which  are  heated 
from  the  outside  by  the  waste  gases  from  the  furnace.  While  these  do  not  give  as  great 
economy  as  the  alternating  brick  regenerators,  they  are  much  less  expensive  and 
troublesome  to  operate.  Of  course  they  cannot  be  used  when  the  temperature  of  the 


GAS   PRODUCERS 

escaping  gases  is  high  enough  to  destroy  iron  pipes.  Terra  cotta  pipes  and  fire-brick 
flues  have  been  used  in  place  of  iron  pipes  for  continuous  regenerators,  but  they  do 
not  conduct  heat  well,  and  are  very  liable  to  crack. 


FIG.  157. — Producer  Gas-fired  Metallurgical  Furnace.    The  pre-heated  air  is  admitted  under  pressure. 

Although  regeneration  should  always  be  employed  when  practicable,  especially 
where  the  waste  gases  escape  at  a  high  temperature,  in  many  kilns  and  furnaces,  when 


FIG.  158.— A  60-inch  Schwartz  Gas-fired  Furnace. 

the  temperature  required  is  not  very  high,  producer  gas  may  be  used  with  marked 
economy  without  regeneration.     This  economy  is  principally  due  to  the  better  facili- 


FURNACES   AND   KILNS 


315 


ties  for  perfect  combustion,  the  fact  that  less  air  is  necessary,  the  saving  of  coal  from 
the  ashes,  and  especially  where  the  producer  is  fed  automatically  and  continuously, 
the  improved  and  uniform  quality  of  the  gas  and  consequent  great  regularity  of  the 
heat  obtained.  Besides  these  the  absence  of  dust,  the  smaller  amount  of  labor 
required,  and  the  substitution  of  a  cheap  for  an  expensive  fuel,  are  often  important 
points.  But  producer  gas  cannot  be  burned  satisfactorily  in  very  small  quantities, 
where  both  gas  and  air  are  cold.  The  flame  is  very  easily  extinguished,  and  even  a 
low  red  heat  is  reached  with  difficulty. 


FIG.  159. — Gas  Connections  to  Schwartz  Furnace. 

In  Europe  producer  gas  has  been  applied  much  more  generally  than  in  this  country. 
We  have  become  thoroughly  familiar  with  its  use,  in  the  heating  furnaces  of  our  iron 
and  steel  mills,  but  it  is  fast  working  its  way  into  other  industries,  such  as  glass 
furnaces,  brick,  pottery,  and  terra-cotta  kilns,  lime  and  cement  kilns,  sugar  house 
char  kilns,  silver  chlorination  and  ore  roasting  furnaces,  for  power  purposes  in  gas 
engines,  etc.  The  introduction  of  producer  gas  has  conclusively  shown  that  when 
made  in  a  good  producer  and  applied  with  a  proper  attention  to  the  laws  governing 
combustion,  a  considerable  saving  is  effected  over  the  former  wasteful  methods. 

The  illustrations  of  tilting  furnaces  show  how  producer  gas  firing  can  be  used  on 
both  a  large  and  small  scale  and  on  a  practical  basis. 


316 


GAS   PRODUCERS 


FIG.  160. — Fire  Tile  Lining  of  Furnace. 


FIG.    161.— Schwart*  Furnaces  of  45  Tons  Capacity  per  day  at  the  Plant  of  the  Magnus  Metal  Co 


FURNACES    AND   KILNS 


317 


•  -  s 


FIG.  162. — Morgan  Producer  and  Furnace  for  Heating  Billets  30  ft.  long. 

Gas  Firing  of  Kilns. — In  the  matter  of  gas  firing  of  ceramic  ware  we  would 
recommend  the  advantages  as  being: 

1.  An  attainment  of  more  perfect  combustion,  as  the   fuel  in  the  gases  formed 
burns  quickly  and  perfectly.     Again  the  transformation  of  heat  into  a  potential  form 
allows  the  combustion  to  take  place  more  nearly  at  the  point  where  the  heat  can  be 
applied  with  the  highest  efficiency,  instead  of  a  consumption  of  fuel  in  the  furnace 
itself,  with  the  resultant  waste  of  radiation. 

2.  Gas  firing  permits  the  use  of  regenerators  for  restoring  a  large  portion  of  the 
waste  heat,  in  the  form  of  sensible  heat,  to  the  gas  and  air,  prior  to  their  admission 
into  the  furnace.     This  fact,  taken  into  combination  with  the  foregoing,  creates  a 
considerable  resultant  economy. 

3.  As  an  advantage  on  the  side  of  gas  firing,  is  the  uniformity  of  heat  obtained, 
which  is  impossible  with  the  direct  furnace,  due  to  variations  and  fluctuations,  as  to 
cooling  apparatus,  cleaning,  etc.;   although  this,  of  course,  occurs  to  some  extent  with 
producer  work,  such  variations  are  reduced  to  a  minimum  by  reason  of  the  intervening 
medium  of  transmission  and  of  equal  fuel  bed. 

4.  In  metallurgical  work  the  loss  by  oxidation  where  producer  gas  is  used  rarely 
exceeds   1%  in  some  instances,  with  a  low  hydrogen  gas  being  even  less,  while  the 
common  practice  of  furnace  work  will  average  3%. 

Finally  and  perhaps  most  important,  is  the  saving  in  labor,  which  is  materially 
diminished  in  producer  work,  by  the  concentration  of  firing,  the  ability  to  use  mechan- 
ical devices,  and  the  reduction  of  actual  coal  handled. 

Brick  and  Tile  Manufacture. — In  the  manufacture  of  tile  and  brick,  five  items 
are  of  particular  importance: 

1.  The  time  or  period  of  the  operation. 


318  GAS    PRODUCERS 

2.  The  continuity  of  operation  of  a  plant  capable  of  manufacturing  at  all  seasons 
of  the  year  and  under  all  conditions  of  weather  and  temperature. 

3.  The  question  of  labor  and  its  reduction  to  a  minimum. 

4.  The  waste,  and  the  manufacture  of  the  finished  product  with  a  minimum  of 
material  including  fuel. 

5.  The  quality  of  the  product. 

One  of  the  most  important  features  in  the  manufacture  of  a  product  of  this  kind 
consists  in  the  pre-drying  of  material.  Inasmuch  as  a  pre-heating  of  the  air  or  elements 
of  combustion  tends  to  shorten  the  flame,  creating  a  shoi't,  stubby,  cutting  flame 
through  the  increase  of  flame  propagation,  when  a  more  voluminous  flame  of  uniform 
temperature  or  combustion  occupying  a  relatively  large  area  is  required  by  the  condi- 
tions of  heat  expulsion  and  the  pnysical  character  of  the  material  it  is  manifestly  best 
to  utilize  all  of  the  waste  heat  possible  for  this  pre-drying  process. 

In  pre-drying  material  two  conditions  are  requisite,  the  first  being  the  application 
of  heat  together  with  its  circulation  throughout  the  material.  The  second  the  escape 
of  the  products  of  condensation  or  aqueous  vapor  expelled,  distilled  or  vaporized 
through  the  action  of  the  heat  thus  applied. 

To  accomplish  this  it  is  manifestly  necessary  to  turn  water  into  vapor,  which  process 
requires  absorption  of  a  definite  amount  of  heat.  For  example,  to  evaporate  a  pound 
of  water  into  vapor  at  the  temperature  of  60°  requires  1070  B.T.U.,  the  vapor  thus 
evaporated  having  a  pressure  of  one-quarter  of  a  pound  per  square  inch  and  1000 
cu.ft.  of  the  vapor  weighing  0.82  pounds. 

The  presence  or  absence  of  air  has  no  effect  upon  the  production  of  aqueous  vapor. 
At  60°  F.  evaporation  will  proceed  until  1000  cu.ft.  of  space  contains  0.82  Ibs.,  when 
evaporation  will  cease  until  the  vapor  is  removed.  If  air  is  present  it  is  said  to  be 
saturated  when  that  condition  obtains  in  which  no  further  evaporation  takes  place. 

Inasmuch  as  air  has  no  chemical  affiinty  for  water  vapor,  it  is  manifest  that  it 
must  be  kept  in  motion  to  sweep  away  through  physical  action  the  water  vapor 
already  formed,  the  escape  of  which  would  otherwise  be  extremely  slow. 

Of  course  at  and  above  a  temperature  of  212°  F.  the  pressure  of  aqueous  vapor 
is  above  atmosphere  and  its  expansion  is  such  as  to  force  aside  atmospheric  or  air 
pressure  without  additional  force. 

Conversely,  therefore,  it  will  be  seen  that  unless  drying  is  conducted  at  a  boiling 
temperature,  or  that  of  212°  or  over,  a  continual  renewal  or  movement  of  the  air  is 
advantageous  or  from  a  practical  standpoint  an  essential  condition,  in  order  that  the 
displacement  may  be  created  for  the  formation  of  more  vapor  or  continued  vaporization. 

Again  the  action  is  dual:  not  only  is  vaporization  accelerated,  but  fresh  supplies 
of  heat  are  brought  in  contact  with  the  material  to  be  dried  in  the  process  of  the 
circulation  thus  maintained. 

There  is  also  a  cooling  effect  upon  material  from  which  moisture  is  evaporated. 
According  to  one  authority,  the  evaporation  of  one  ounce  of  wyater  from  a  pint  would 
reduce  the  temperature  of  the  whole  pint  from  96°  F.  to  32°  F.  or  freezing  point, 
were  no  extraneous  heat  supplied. 

In  sun-dried  brick  or  tile  the  evaporation  occurs  through  the  radiant  heat  from 
the  sun  and  by  contact  with  surounding  objects,  principally  that  of  the  enveloping 
air.  In  an  artificial  drying  of  brick  and  tile  the  heat  for  drying  has  been  heretofore 


FURNACES   AND   KILNS  319 

supplied  by  the  combustion  of  fuel  and    very  considerable  expense.     The  usual  drying 
may  be  divided  into  three  classes: 

1.  Drying  due  to  products  of  combustion  circulating  among  the  material  which 
in  driving  off  aqueous  vapor  is  termed  "  water  smoking." 

2.  By  imparting  heat  from  the  products  of  combustion  to  clean  air  and  allowing 
the  latter  to  dry  the  brick,  as  in  the  case  of  the  hot  air  or  hot  blast  drier. 

3.  The  utilization  of  heat  primarily  created  in  burning  or  calcining  the  material 
within  a   kiln;    then   drawing  through  the  burned   or  calcined  mass  left,  at  a  high 
temperature,  a  volume  of  fresh  air,  while  the  kiln  is  in  a  cooling  state,  the  air  being 
induced  or  forced  by  means  of  fans;  the  air  becoming  heated  in  this  passage  performs 
the  dual  function  of  cooling  the  kiln  and  material,  and  of  heating  or  drying  the  green 
material  in  the  second  kiln  through  which  it  is  forced,  known  as  the  "  green  kiln," 
this  being  termed  the  "  waste  heat  "  process. 

4.  The  fourth  plan  is  that  of  using  the  heat  of  combustion  to  generate  steam  in 
the  boiler  and  passing  this  steam  through  the  medium  of  pipe    coils   underneath  the 
drying  floor,  and  through  pipe  partitions  \vhere  it  heats  the  air  which  in  turn  circu- 
lates through  the  material  to  be  pre-dried,  its   action   being  both  by  radiation  and 
conduction.     It  is  termed  the  old  style  "  hot  floor  "  or  "  direct  dryers  "  method. 

5.  The  fifth  method  is  that  of  generating  steam  which  is  used  in  heater  coils  to 
heat  air  within  a  chamber,  which  being  brought  up  to  a  certain  temperature  is  forced 
by  fans  through  the  material  to  be  dried.     This  is  known  as  the  indirect  or  hot  blast 
system  and  while  efficient  is  most  extravagant  in  cost. 

In  the  last  two  systems  exhaust  steam  may  be  used,  as  it  contains  from  80  to 
90%  of  the  heat  originally  contained  by  the  live  steam,  it,  however,  possessing  the  draw- 
buck  that  the  amount  of  exhaust  steam  necessary  for  the  purpose  is  not  usually  avail- 
able, as  it  is  disproportionate  in  its  volume  or  amount  with  the  boiler  installation  neces- 
sary to  be  maintained  in  a  plant  of  this  character,  or  for  the  mechanical  load  factor. 

It  is  evident  that  the  economic  adoption  suggested  by  a  comparison  of  these 
systems  will  show  the  rational  method  to  be  the  third  type  or  "  waste  heat  process  " 
inasmuch  as  it  permits  the  regeneration  and  use  of  a  by-product  of  heat  which  must 
be  otherwise  totally  lost. 

The  method  of  interchangeable  connection  between  the  kilns  permitting  any 
combination  of  series  or  multiple  to  be  made,  enables  each  green  kiln  in  burning  to 
act  as  a  regenerator  or  economizer  for  its  predecessor  in  a  cooling  state,  also  the  blast 
of  cool  air  induced  or  forced  through  the  cooling  kiln  increases  the  cooling  process, 
effecting  a  time  economy  of  not  less  than  2oc'c,  hence  materially  increasing  the  output 
of  the  plant  per  kiln. 

Large  fans  of  the  Green  fuel  economizer  type  especially  designed  for  the  handling 
of  heated  gases  are  usually  used.  They  run  at  a  comparatively  low  speed,  and  the 
power  required  is  relatively  small. 

Instead  of  the  piping  shown  in  the  illustration,  it  is  possible  to  use  flues  or  tunnels 
underground  with  proper  valves  and  by-passes,  which  have  perhaps  a  higher  insulat- 
ing quality.  They  have,  however,  the  disadvantage  of  becoming  readily  water 
trapped,  unless  made  with  great  care  and  with  expensive  construction. 

Spiral  pipe,  riveted  pipe,  or  even  No.  12  galvanized  blast  pipe,  the  latter  being 
duly  supported,  may  be  used  in  connection  with  the  arrangement  mentioned,  and 


GAS   PRODUCERS 


it  is  even  possible  to  line  this  pipe  with  fire-brick,  or  in  cases,  to  cover  it  with  some 
insulating  material,  the  former  being  the  better  arrangement  to  reduce  its  radiation 
losses. 

Another  salient  feature  is  reduction  in  cost  of  firing,  and  its  attendant  labor. 
This  is  due  to  the  fact  that  while  the  producer  requires  a  crew  of  but  two  men  per 
shift,  and  may  be  fed  by  a  satisfactory  conveyor  or  feed  hopper,  or  some  other  device, 


FLflNT  LflYfiUT 


—ran  — 


MflXfMUM  HECHVEPY  HP  WfJS  TE  HSffT  \  MINIMUM  LflffDR 


FIG.  163. — Brick  Plant  Heated  by  Producer  Gas.     Arrangement  and  connections. 

the  direct  fired  kilns  have  all  the  way  from  two  to  eight  furnaces  and  rarely  ever 
have  less  than  two  men  per  kiln  per  shift,  hence  it  will  be  seen  that  the  reduction 
of  labor  is  about  75%. 

Again  the  operation  of  burned  kilns  under  direct  firing  is  exceedingly  difficult, 
due  to  slagging  and  the  formation  of  clinker.  This  may  be  to  a  great  extent 
obviated  in  the  producer  by  the  manufacture  of  gas  at  a  lower  temperature  than 
that  of  the  fluxing  point  of  fusible  ash. 


FURNACES   AND  KILNS 


S21 


It  is  of  course  admitted  that  this  condition  is  materially  dependent  upon  the 
nature  of  the  coal.  In  any  case,  however,  it  may  be  relatively  reduced. 

Again  the  other  losses  relative  to  gaseous  combustion,  especially  those  regarding 
localization  of  temperature  and  the  accomplishment  of  combustion  without  air  excess, 
are  particularly  emphasized  in  this  application. 

Consequent  upon  the  former  the  uniformity  of  the  product  is  materially  enhanced, 
the  "  burn  "  due  to  a  voluminous  combustion  instead  of  a  high  localized  temperature 
or  reducing  flame  is  much  more  even  throughout,  resulting  in  less  over-burned  brick 
at  the  sides,  crocking  and  vitrifying,  and  less  green  or  unbaked  brick  at  the  center  or 
remote  from  the  flue  passages. 

The  installation  cost  of  down-draft  kilns  in  connection  with  an  arrangement  of 
this  kind,  is  comparatively  high,  but  when  its  continuity  of  service  is  taken  into 


FIG.  164. — Brick  Kiln  with  Mechanical  Draft. 

consideration  (the  service  of  the  Scotch  or  Summer  kiln  will  not  average  through 
the  United  States  more  than  four  months  per  annum),  together  with  the  increased 
cost  and  scarcity  of  wood,  there  is  but  little  doubt  that  this  arrangmeent  will  be 
shortly  adopted  exclusively,  with  the  exception  of  certain  southern  territory  where 
the  winters  are  open  and  wood  fuel  yet  plentiful.  For  fire-brick  and  other  tile  requiring 
any  degree  of  perfection  or  uniformity  of  product,  this  mtehod  has  become  well 
established. 

Taking  into  consideration  comparative  industrial  work,  the  down -draft  kiln  is 
certainly  extremely  effective.  This  is  due  to  the  dissemination  of  gases  and  combustion 
throughout  it?  area  and  the  reverberatory  effect  of  its  conical  dome.  The  lines  of  this 
dome  by  the  way  should  be  so  calculated  as  to  prevent  extreme  convergency  of  the 
reflected  heat  rays,  as  such  an  error  frequently  occasions  concentration  and  irregu- 
larities of  temperature. 


322 


GAS   PRODUCERS 


It  should  be  borne  in  mind  in  the  designing  of  these  kilns  that  the  law  of  area  to 
volume  is  particularly  potent,  that  is  to  say,  while  the  contents  of  the  kiln  increase 
as  the  cube  of  the  dimensions  the  radiating  surface  varies  only  as  the  square;  hence 
within  certain  structural  limits  the  larger  the  kiln  the  more  efficient,  for  the  mass  of 
contents  once  heated  acts  as  a  most  efficient  burner  and  the  principal  heat  loss  of  the 
kiln  is  due  to  radiation. 

The  gas  is  usually  conducted  to  the  various  portions  of  the  kiln  through  brick 
flues,  the  main  flues  being  permanent  in  structure.  Great  care  should  be  taken  in 
making  the  main  conduits  and  walls  of  the  kiln  extremely  tight  as  any  leakage  is 
promotive  of  air  excess  and  consequent  economy  less  in  combustion.  The  best  results 
of  this  combustion  has  generally  been  obtained  when  an  analysis  of  the  flue  gases 
shows  just  a  trace  of  CO,  say,  half  of  one  per  cent;  this,  however,  is  rarely  possible 
by  reason  of  the  kiln  leakage. 


Coo 


FIG.  165. — Arrangement  of  Pre-heated  Air  Flue. 

Youngren  Kilns. — The  continuous  kilns,  of  which  the  Youngreri  is  one  of  the 
most  prominent  types,  is  built  of  a  series  of  communicating  chambers  (see  illustration), 
arid  is  divided  into  two  general  glasses  known  as  the  "  tunnel  "  and  "  chambered  " 
kiln,  the  former  being  cheaper  to  construct,  but  the  latter  requiring  much  less  labor 
in  operation,  together  with  making  a  more  uniform  product. 

The  number  and  size  of  the  chambers  is  regulated  by  the  capacity  of  plant,  the 
nature  of  the  clay,  and  the  length  of  time  it  takes  to  set,  dry,  water  smoke,  burn, 
cool  and  empty  a  chamber.  The  combined  holding  capacity  of  all  the  chambers 
should  be  from,  sixteen  to  twenty  times  the  daily  capacity  of  the  plant.  A  continuous 
kiln  is  especially  adapted  to  the  burning  of  all  kinds  of  the  better  grades  of  clay  ware 
which  are  usually  burned  in  "  down-draft  "  kilns,  such  as  face-brick,  paving-brick, 
terra  cotta,  fire -proofing,  drain  tile,  etc.,  as  well  as  for  common  building  brick. 

The  cycle  of  operation  on  a  12-chambered  kiln,  such  as  that  shown  in  the  illus- 
tration, is  as  follows: 

Bricks  arc  being  alternately  set  and  dried  in  chambers  Nos.  1  and  2. 

No.  3  is  being  emptied  and  cleaned  out  preparatory  to  setting  when  No.  1  is  filled. 


FURNACES   AND    KILXS 


323 


Xo.  4  is  nearly  cool,  the  caps  having  been  removed  from  the  crown,  the  doors 
and  wickets  being  open. 

Xos.  5,  6,  and  7  are  in  their  various  stages  of  cooling. 

Air  for  cooling  is  admitted  into  chamber  Xo.  4,  and  is  circulated  through  Nos. 
4,  5,  6,  and  7;  it  then  passes  through  Xo.  S,  which  is  red  hot,  the  firing  having  recently 
ceased;  this  hot  air  then  goes  on  to  supply  combustion  for  firing  in  chambers  Xos.  9 
and  10;  the  products  of  combustion  given  off  by  these  latter  two  chambers  pass  through 
Xo.  11  and  raise  its -temperature  to  a  straw  heat,  ready  for  direct  firing,  after  which 
the  gases  pass  on  through  Xo.  12,  which  has  just  been  sealed  up. 

Surrounding  the  chambers  is  a  hot  air  or  waste  heat  duct,  to  which  is  attached 
an  induced  draft  fan.  In  the  cycle  just  described,  this  fan  pulls  directly  on  Xo.  12, 


FIG.  166. — Diagram  Plan  of  Youngren  Continuous  Producer-fired  Brick  Kiln. 

discharging  freely  into  the  atmosphere.  The  draft  thus  created  causes  the  circulation 
just  described  through  all  the  other  chambers  back  to  and  including  Xo.  4,  where  the 
air  is  first  admitted. 

Supposing  the  start  is  made  in  chamber  Xo.  1,  and  further,  that  the  chambers 
are  of  such  size  that  a  tier  of  brick  will  equal  half  a  day's  output;  then  at  noon  the 
setters  will  shift  over  to  chamber  Xo.  2  for  the  afternoon,  heat  and  air  being  turned 
into  Xo.  1  to  dry  the  bricks  set  therein.  The  next  morning  the  setters  start  in  Xo.  1 
again,  this  alternate  setting  and  drying  being  repeated  and  the  conveyors  remaining 
in  their  respective  chambers  until  the  kiln  is  filled. 

The  heat  and  air  for  drying  the  bricks  are  obtained  from  a  bank  of  encased  steam 
coils  and  a  blower.  The  coils  are  supplied  with  exhaust  steam  from  the  main  engine, 
blower  engines,  feed  pumps,  etc.,  this  being  supplemented  by  whatever  live  steam 
is  required.  The  duct  which  conveys  the  air  to  the  chamber  passes  between  the  two 
rows  of  chambers,  suitable  dampers  being  provided  for  opening  and  closing  communi- 


324  GAS   PRODUCERS 

cation  between  this  duct  and  the  chambers  on  either  side  of  it.  Single  battery  kilns 
can  be  constructed  when  local  conditions  warrant  it,  the  process  being  made  continuous 
by  a  return  duct  from  the  last  to  the  first  chamber  to  convey  the  heat  and  gases. 

The  gas  producer  is  preferably  located  at  one  end  of  the  kiln.  The  main  gas  duct 
is  carried  across  the  end  and  along  both  sides  of  the  kiln  outside  the  hot  air  duct. 
From  the  bottom  of  the  duct  smaller  ducts  extend  across  beneath  the  hot  air  duct, 
exactly  opposite  the  walls  between  the  chambers.  These  latter  ducts  lead  to  short 
flues  in  the  division  walls,  at  the  tops  of  which  are  distributing  passages  to  convey 
the  gas  to  the  openings  leading  into  the  combustion  chambers  behind  the  flash  walls. 
The  gas  ignites  immediately  upon  entering  the  combustion  chamber,  the  intensity 
of  the  heat  being  regulated  to  a  nicety  by  a  valve  operated  by  the  wheel  on  the 
controller  column. 

As  already  mentioned,  the  fresh  air  which  supports  combustion  is  heated  to  a  very 
high  temperature  by  first  passing  through  the  chambers  which  have  been  burned  and 
are  being  cooled  off.  The  amount  of  air  can  also  be  controlled  by  dampers  operated 
from  the  top  of  the  kiln  so  as  to  get  the  highest  combustion  efficiency.  The  air  and 
gas  are  mixed  in  their  proper  proportion  just  before  entering  the  combustion  chamber. 

The  induced  draft  fan  not  only  gives  the  required  draft  for  combustion  but  also 
maintains  the  proper  circulation  of  air  through  the  chambers  which  are  cooling  off, 
and  draws  the  products  of  combustion  through  the  chambers  which  have  been  set, 
thus  doing  the  water  smoking  and  raising  the  temperature  up  to  the  point  where  firing 
can  begin. 

In  the  crowns  of  the  kilns  are  vents,  the  covers  of  which  can  be  removed  to 
accelerate  the  cooling  of  the  chambers. 

The  heat  for  drying  is  obtained  from  the  bank  of  steam  coils  which  are  enclosed 
in  a  steel  jacket.  The  blower  draws  fresh  air  across  the  coils  and  discharges  into  the 
warm  air  duct. 

The  air  for  drying  is  admitted  to  the  chambers  through  openings  in  the  end  walls, 
and  the  heat  given  off  by  the  bricks  in  cooling  is  drawn  through  openings  at  the  opposite 
end  of  the  chambers.  The  blower  can  be  driven  by  a  direct-connected  engine  or  by  a 
belted  engine  or  motor.  Manhole  plates  are  provided  for  easy  access  to  all  the  ducts. 

The  main  conveyer  is  suspended  from  cables,  which  latter  wind  around  a  shaft 
for  raising  and  lowering  the  conveyer,  according  to  the  height  of  the  courses  of  bricks 
as  the  setting  progresses.  The  cross  conveyer,  which  carries  the  bricks  from  the 
main  conveyer  into  the  chambers,  is  simply  a  light,  ball-bearing,  gravity  conveyer, 
one  end  of  which  is  supported  by  the  main  conveyer,  the  other  end  resting  on  a  tripod 
inside  the  kiln. 

Owing  to  the  very  high  temperature  of  the  air  which  supports  the  combustion  of 
the  gas,  the  general  atmosphere  in  the  burning  chambers  is  usually  highly  oxidizing. 
Should  this  be  undesirable,  the  required  chemical  reactions  during  the  burning 
process  can  be  readily  produced.  This  is  accomplished  by  maintaining  a  reducing 
atmosphere  periodically,  which  is  brought  about  by  shutting  off  the  air  supply  in 
the  connecting  passages  between  the  cooling  chambers,  by  suitable  dampers  provided 
for  that  purpose. 

The  condition  within  the  kiln  can  be  changed  in  less  than  two  minutes,  from  an 
oxidizing  character  to  a  neutral  or  more  or  less  powerful  reducing  character,  by  a 


FURNACES   AND   KILNS  325 

simple  manipulation  of  valves.  No  rules  can  be  laid  down  as  a  guide  for  the  treatment 
of  different  clays,  during  the  various  stages  of  making  into  bricks.  By  this  arrange- 
ment a  saving  of  from  24  to  36  hours  is  effected  in  drying  time,  besides  the  drying 
being  made  more  effective.  The  water  smoke  period  is  reduced  about  one-half. 

The  bricks  are  set  in  about  the  same  manner  as  usual,  except  that  the  number 
of  courses  high  has  to  be  regulated  according  to  the  stiffness  of  the  clay  and  the 
ability  of  the  bricks  in  the  lower  courses  to  support  the  weight  of  those  above.  This 
varies  from  six  to  thirteen  courses  with  different  clays. 

When  the  entire  bottom  of  the  kiln  has  been  covered  with  bricks,  set  as  many 
courses  high  as  has  been  found  practicable,  the  setters  raise  the  conveyer  to  the  proper 
height  for  the  next  tier,  and  then  go  into  another  kiln  or  chamber  to  repeat  the  opera- 
tion while  the  bricks  previously  set  are  allowed  to  dry. 

When  the  bricks  in  the  first  tier  have  dried,  the  setters  begin  setting  another  tier 
on  top  of  them.  This  is  repeated  until  the  kiln  is  filled,  when  the  conveyer  is  with- 
drawn and  moved  to  another  kiln  or  chamber.  The  last  tier  dried,  the  kiln  door  is 
then  cased  up,  and  the  kiln  burned  in  the  same  manner  as  though  the  bricks  had 
been  dried  in  a  typical  car  system  or  tunnel  drier. 

The  first  tier  need  only  be  dry  enough  to  support  the  weight  of  the  second. 
The  heat  passes  over  the  first  tier  before  reaching  the  second,  when  the  latter  is 
ready  for  drying,  and  over  the  first  and  second  to  dry  the  third,  and  so  on  until  it 
finally  reaches  the  top  tier.  When  the  top  course  is  dry,  the  bottom  courses  are  thor- 
oughly dry  and  as  hot  as  the  hot  air  will  make  them,  the  kiln  being  in  a  perfect  condi- 
tion to  start  firing  without  water  smoking. 

The  circulation  of  air  is  necessary  to  carry  off  the  moisture  is  produced  by  one  or 
more  fans  or  blowers.  The  motive  power  can  be  either  a  steam  or  gas  engine,  or  an 
electric  motor. 

The  air  for  supplying  combustion  is  heated  to  a  very  high  temperature  while 
performing  the  service  of  cooling  the  chamberc  already  burned.  The  hotter  the  air 
is,  the  less  fuel  is  requred. 

In  metallurgical  furnaces  of  the  open-hearth  type  a  saving  of  30%  is  assumed 
to  be  effected  where  furnace  is  of  the  full  muffler  type  with  complete  regeneration. 
Where  over  2000°  F.  is  required  and  up  to  3000°,  the  secondary  air  must  be  highly 
pre-heated.  Above  3000°  air  and  gas  should  be  pre-heated  to  the  maximum. 

The  saving  in  brick  or  ceramic  kiln  gas  firing  over  direct  firing  is  usually  estimated 
at  40%  under  conditions  of  proper  applications.  Temperatures  in  kilns  or  furnaces 
of  this  kind  are  relatively  low. 

Schmatolla  High  Temperature  Kiln  is  based  on  the  Siemens  system,  which 
had  been  in  use  a  long  time,  for  example,  in  the  steel  industry.  The  system  chiefly 
consists  in  the  particular  connection  of  the  heating  chamber  a  with  two  or  more  heat 
collectors  or  accumulators  b,  and  a  generator,  which  is  arranged  beteewn  the  heating 
chamber  and  the  regenerating  chambers  in  such  manner  as  to  form  a  single  block  of 
masonry  with  the  former,  and  with  the  latter,  so  that  losses  of  heat  from  the  generator 
or  in  the  gas  conduits  or  flues  are  quite  impossible.  The  furnace  c  is  constructed  in 
such  manner  that  it  can  be  first  used  as  a  directly  fired  chamber  furnace,  and  then 
gradually  changed  to  gas  firing  from  the  same  furnace  c.  The  gas  generator  c,  which 
is  built  in  a  similar  way  as  a  grate  furnace,  but  with  a  higher  shaft,  is  arranged  below 


326 


GAS   PRODUCERS 


the  burning  chamber  a,  and  the  two  heat  collectors  or  accumulators  reach  approxi- 
mately from  the  bottom  end  of  the  gas  generator  to  the  upper  end  of  the  heating  or 
burning  chamber.  The  gas  generator  is  connected  to  the  chamber  at  both  sides  by 
means  of  conduits  or  flues  d  e,  between  which  are  arranged  dampers  /,  the  latter 
enabling  to  close  the  one  or  the  other  of  the  flues  d.  The  two  heat  collectors  b  are 
connected  to  the  heating  or  burning  chamber  a  by  means  of  conduits  g  and  openings 
h.  The  heat  collectors,  which  are  provided  with  a  grating  of  refractory  stones  or 
other  material,  are  connected  at  the  bottom  end  to  conduits  ft1,  b2,  b3,  b4,  which  can 
be  brought  into  communication  either  with  the  chimney  channel  65,  or  with  the  outer 
air,  by  means  of  a  device  consisting  of  a  box  k,  shown  in  the  lower  part.  Assuming 
that  the  damper  /  on  the  left-hand  side  is  closed,  the  corrseponding  damper  /  on  the 


FIG.  167. — The  Schmatolla  High  Temperature  Ceramic  Kiln. 

right-hand  side  being  open,  and  the  box  stands  as  shown  in  the  drawing,  the  conduit 
b4  on  the  right-hand  side  is  in  connection  with  the  outer  air,  and  the  conduit  b4  on 
the  left-hand  side  is  connected  with  the  chimney;  and,  assuming  further  that  the 
generator  is  filled  with  coal  and  that  the  whole  furnace  is  already  incandescent,  the 
generator-gas  will  then  pass  through  the  right-hand  conduit  system  d  e  into  the  heating 
chamber  a,  and  the  air  through  the  right-hand  conduit  system  b4,  b2,  b3,  b1,  the  grating 
of  the  right-hand  heat  collector  and  the  conduits  g  h  also  into  the  heating  chamber. 
Gas  and  air  become  mixed  at  the  right-hand  end  of  the  chamber,  burn  in  the  interior 
of  the  chamber  a,  and  pass  at  the  other  end  through  the  conduits  h  g  and  the  heat 
collectors  h,  as  well  as  the  conduits  b1,  b3,  b2,  b4  on  the  left  hand  into  the  chimney.  The 
combustion  gases  escaping  from  the  chamber  give  off  the  greatest  portion  of  their 


FURNACES   AND   KILNS  327 

heat  to  the  grating  of  the  heat  collector  arranged  on  the  left-hand  side.  When  the 
latter  is  saturated  with  heat,  that  is  to  say,  already  highly  heated,  so  that  the  combus- 
tion gases  begin  to  escape  through  the  flues  b1,  b8,  b2,  b4,  with  a  high  temperature,  the 
box  A-  is  drawn  to  the  right  side,  so  that  the  left  channel  b4  be  open  and  right  channels 
b1,  b2,  b3,  b4,  with  the  chimney  are  closed,  whilst  the  right-handed  flue  system  b1,  b2,  b3,  b4 
is  connected  to  the  chimney.  If,  then,  the  right-hand  damper  /  be  closed,  and  if 
thereupon  the  left-hand  damper  /  is  opened,  the  generator  gas  will  pass  through  the 
left-hand  side  flues  e  and  g  into  the  chamber,  and  the  air  will  pass  thrugh  the  left-hand 
side  flues  64,  b3,  b2,  b1,  the  grating  of  the  left-hand  side  heat  collector  6,  and  the  left- 
hand  side  flues  g,  h  into  the  chamber  a'.  The  flame  in  the  latter  will  follow  the 
opposite  path  as  before,  and  pass  on  the  other  side  through  the  flues  g,  h,  the  grating 
of  the  heat  collector,  and,  after  having  given  off  to  the  latter  the  greater  portion  of  its 
heat,  through  the  right-hand  flues  61,  b2,  b3,  into  the  chimney.  The  air  is,  of  course, 
highly  heated  on  the  way  by  the  previously  highly  heated  grating  of  the  left-hand 
side  heat  accumulator  and  passes  into  the  chamber  with  a  very  high  temperature. 
Assuming  that  coal  or  some  other  high-grade  fuel  is  used,  the  generator  gas  will 
pass  into  the  heating  chamber  with  a  very  high  temperature,  since  it  has  to  traverse 
only  a  short  conduit,  and  thus  it  is  possible  to  increase  the  temperature  in  the  said 
chamber  to  a  much  higher  degree  than  was  hitherto  possible  in  the  furnaces  gen- 
erally used  in  various  industries,  for  instance,  for  burning  or  heating  highly  refractory 
materials.  As  the  direction  of  the  flames  can  be  altered  at  given  time  intervals,  the 
temperature  in  the  chamber  can  be  raised  as  much  as  desired  up  to  the  limit  of  the 
dissociation  temperature  of  carbonic  gas,  that  is  to  say,  up  to  2000°  C. 


CHAPTER   XIV 
BURNING   LIME  AND   CEMENT 

Lime  and  Calcining. — A  difficulty  in  the  use  of  gaseous  fuel  in  the  ceramic  and 
calcining  industries  has  been  largely  due  to  a  lack  of  cooperation  of  the  gas  engineer 
and  the  kiln  designer.  Upon  the  part  of  the  former  there  has  been  a  lack  of  incom- 
plete knowledge  of  just  what  is  required  in  the  way  of  degree  of  temperature,  condi- 
tions of  regulation  and  quantity  of  heat.  Upon  the  part  of  the  latter  there  has  been 
an  inexact  understanding  of  the  laws  and  actions  of  gaseous  fuel.  There  can  be  but 
little  doubt  that  when  these  are  brought  together  and  harmonized  that  the  adoption 
of  gaseous  fuel  will  be  the  logical  act  of  all  of  these  industries,  principally  for  the 
following  reasons: 

1.  Foremost  will  be  the  utilization  of  low  grade  fuel,  which  under  conditions  of 
direct  firing,  by  reason  of  its  content  of  water,  ash,  and  its  tendency  to  clinker,  will 
not  supply  the  requisite  heat  effect. 

2.  With  a  proper  application  an  almost  unlimited  heat  intensity  can  be  obtained. 

3.  More  important,  the  regulation  of  this  heat  can  be  made  positive  and  with 
complete  facility. 

4.  The  action  of  the  gas  flame  is  more  mild  and  diffused  than  that  of  the  direct 
flame  and  the  tendency  is  for  a  more  extended  and  distributed  combustion,  and  less 
intense  localization  of  heat  which,  when  occurring  in  the  arches  through  the  medium 
of  coal  burning,  is  so  objectionable  a  feature  and  so  wasteful  of  fuel. 

5.  The  centralization  of  the  producers  permit  a  reduction  of  labor  and  an  ease  of 
operation  over  the  firing  of  separate  and  several  arches. 

6.  The  uniformity  of  the  heat  and  the  diffusion  of  its  combustion  tends  to  a  more 
uniform  burning  of  the  product. 

7.  Clinkering  in  the  grates  of  the  arches  is  eliminated  with  its  consequent  loss 
of  fuel  and  wear  upon  the  linings. 

8.  A  cleaner  and  more  uniform  product. 

Finally  the  combustion  is  more  thorough.  To  quote  from  Orton,  "  Another 
source  of  economy  lies  in  the  fact  that  it  is  possible  to  approximate  much  more  closely 
to  the  theoretical  perfect  combustion.  To  burn  a  pound  of  coal  requires  an  average 
of  about  11  Ibs.  of  air,  yet  we  often  use  22  or  33  Ibs.,  or  even  55  Ibs.  of  air  per  pound 
of  coal  in  actual  operation.  An  excess  of  300%  of  the  theoretical  amount  of  air  required 
is  not  uncommon.  With  the  use  of  producer  gas,  it  is  quite  safely  possible  to  cut  clown 
the  excess  of  air  in  cases  where  it  is  the  intention  merely  to  consider  the  efficiency 
of  heat  production.  In  clay  burning  the  chemical  condition  of  the  atmosphere  is 

328 


BURNING    LIME    AND   CEMENT  329 

often  most  important,  and  all  questions  of  fuel  economy  must  be  considered  as 
secondary  to  this.  But  it  is  possible  in  the  use  of  gas  to  limit  the  excess  of  air  very 
much  more  than  with  solid  fuel,  while  still  maintaining  an  oxidizing  fire,  and  conse- 
quently there  is  much  less  heat  carried  out  as  sensible  heat  of  the  waste  gases,  and  so 
economy  may  come  in  that  way." 

It  must  be  borne  in  mind  that  for  the  dissociation  of  CACOs  there  must  be  a 
minimum  temperature  of  about  900°  C.  or  something  over  1800°  F.  The  application 
of  producer  gas  whose  flame  temperature  is  normally  only  about  1200  to  1400°  F.,  so 
u.s  to  attain  this  temperature  must  be  a  matter  of  careful  and  special  design,  and  it  is 
safe  to  allow  at  least  for  the  obtaining  of  a  temperature  as  high  as  1000°  C.  permitting 
thereby  a  factor  of  safety  or  a  reserve  of  power. 

Of  course  a  highly  silicated  lime  will  not  stand  a  heat  much  over  say  1900°  F., 
but  in  the  opinion  of  the  writer  the  degree  of  heat  should  only  be  limited  by  the 
amount  of  silicate  contents  in  the  limestone. 

Another  thing  which  must  be  borne  in  mind  is  that  the  cooling  chamber  of  a  lime 
kiln  affords  exceptional  opportunities  for  pre-heating  the  secondary  air  for  combustion. 
This  secondary  air,  however,  should  not  be  raised  to  a  temperature  above  300  to  400° 
F.  inasmuch  as  a  higher  degree  of  temperature  tends  to  shorten  the  flame  to  a  point 
which  is  impracticable  for  lime  burning. 

This  pre-heated  air  when  so  used  may  be  admitted  for  combustion  of  the  gas  in 
an  amount  not  over  10%  in  excess  of  the  theoretical  requirement;  this  10%  excess 
of  course  including  the  leakage  of  the  kiln  and  such  air  as  may  work  up  through  the 
dumping  hopper  and  cooling  chamber. 

In  any  operation  certain  data  must  be  secured,  in  order  that  the  demands  of  each 
particular  condition  be  specifically  known.  Primarily  this  information  consists  as 
follows:  First,  the  character  of  the  limestone  to  be  burned,  the  temperature  at  which 
it  calcines  most  completely,  the  amount  of  heat  required  to  calcine  a  given  amount  of 
limestone,  the  type  of  kiln  required  for  the  operation,  the  nature  and  character  of  the 
fuel  available.  Now,  when  this  information  is  secured  it  is  only  necessary  to  comply 
with  these  requirements  or  demands  to  secure  positive  results.  To  the  failure  in 
considering  these  several  conditions  I  would  attribute  the  failure  of  burning  lime 
with  producer  gas,  almost  universally  met  with  hitherto  in  the  United  States. 

There  can  be  no  doubt,  however,  that  where  the  conditions  are  intelligently 
considered,  that  plants  can  be  designed  where  the  demanded  heat  conditions  can  be 
supplied  and  the  results  obtained  will  be  the  highest  degree  of  efficiency,  both  from 
economy  of  production  and  quality  of  product  to  which  the  art  of  limestone  burning 
may  attain. 

Lime  Burning  with  Natural  Gas. — A  lime-burning  operation  with  natural  gas 
has  been  successfully  conducted  at  Sugar  Rapids,  0.,  for  Mr.  Peter  Martin,  of  the 
Ohio  &  Western  Lime  Co.,  for  some  fifteen  years,  a  brief  description  of  wThich  is  as 
follows:  The  arches  being  originally  designed  for  wood  are  about  3  ft.  wide  and  2  ft. 
high,  and  although  giving  satisfactory  results,  are  unnecessarily  large.  It  is  not 
necessary  in  fact  that  the  arches  be  larger  than  2  ft.  wide  and  20  ins.  high,  which  would 
answer  all  purposes.  Within  the  arches,  2  in.  pipes  are  laid,  one  on  each  side  of  the 
arch.  Into  these  pipes  the  gas  is  induced  from  f  in.  pipes,  with  a  mixer  at  the  end, 
making  a  form  of  Bunsen  burner  similar  to  the  type  used  in  the  oven  of  a  gas  range. 


330  GAS   PRODUCERS 

The  mixers  are  equipped  with  slides  for  air  regulation,  and  the  whole  arrangement  is 
similar  to  the  natural  gas  supply  to  a  gas  range. 

The  arches  are  5  ft.  in  length  inside,  and  the  pipes  are  laid  so  that  they  reach 
within  about  4  ins.  of  the  inside  of  the  arch  or  shaft  of  the  kiln.  The  ash  pits  under- 
neath the  kiln  are  rilled  in  tight  with  air-slaked  lime,  so  that  no  air  can  get  into  the 
ash  pits.  The  maintaining  of  the  kilns  tight  is  particularly  important  to  prevent 
over-ventilation  or  an  excess  of  air. 

The  great  difficulty  in  regulating  the  combustion  in  a  kiln  of  this  type  lies  in  too 
intense  a  temperature,  and  in  over-burning  or  in  case-burning  the  lime. 

Mr.  Martin  recommends  a  kiln  about  22  ft.  in  height  from  the  arch  to  the  top, 
and  about  6  ft.  in  diameter.  He  also  states  that  a  moderately  low  kiln  possesses  a 
better  draft  than  a  kiln  that  is  too  high,  this  probably  being  dependant,  however, 
upon  the  ratio  of  the  height  to  the  diameter,  in  proportion  to  the  total  voids  in  the 
charge. 

Vertical  Lime  Kilns. — In  the  burning  of  limestone  (CACOs)  to  lime  (CaO)  a  para- 
dox presents  itself  in  the  fact  that  the  softer  the  limestone  and  the  more  ameanable 
to  heat,  the  more  difficult  is  its  complete  calcination.  This  is  by  reason  of  the  fact 
that  at  an  early  stage  of  the  process  the  limestone  disintegrates,  powders,  pulverizes, 
or  "  fines,"  forming  a  compact  mass  comparatively  impenetrable  to  both  heat  and 
gases,  which  retards  the  further  calcination  and  additional  expulsion  of  CC>2.  The 
physical  structure  of  the  limestone,  in  the  opinion  of  the  writer,  has  much  more  to 
do  with  the  conditions  of  quality  of  burning  than  that  of  its  chemcal  analysis,  prin- 
cipally for  the  reason  above  cited. 

In  the  use  of  shaft  kilns  these  conditions  can  be  somewhat  regulated  by  the  size 
of  the  stone  or  ore  charged.  By  experimental  determination  of  the  relative  draft  of 
each  kiln  in  connection  with  the  stone  to  be  used,  the  most  economic  size  may  be  ascer- 
tained. Generally  speaking  the  writer  favors  limestone  fragments  of  approximately 
8X8X12  ins.,  for  it  has  been  his  experience  that  whereas  the  large  stone  means  a 
slight  increase  in  fuel  per  kiln,  yet  there  is  a  more  than  commensurate  output  per  kiln 
and  a  reduction  of  fuel  per  unit  of  lime  manufactured. 

The  use  of  exhausts  in  connection  with  shaft  kilns  may  be  advocated  where  such 
kilns  have  naturally  bad  drafts,  in  which  case  not  only  the  process  of  combustion, 
but  the  C02  evolved  from  the  dissociation  of  the  limestone  may  be  more  readily  and 
speedily  removed,  although  under  ordinary  circumstances  the  degree  of  draft  can  be 
largely  regulated  by  the  size  of  stone  charged  as  aforesaid  and  any  advantages  attained 
from  the  use  of  the  exhauster  are  offset  by  the  tendency  of  the  exhaust  to  wire-draw 
or  channel  the  gases  through  the  charge  and  to  over-ventilate  the  kiln,  that  is  to  say, 
produce  air  excess  through  superinduced  leakage,  there  being  leaks  in  nearly  all  kilns, 
especially  in  the  neighborhood  of  the  dumping  hoppers. 

Many  experienced  lime  burners  believe  that  the  advantages  so  well  known,  as 
accruing  from  wood  or  flame  burned  lime,  are  caused  by  the  large  moisture  content 
in  the  wood  fuel.  It  is  extremely  possible  that  there  is  some  eruptive  or  disintegrating 
action  between  such  moisture  and  the  limestone,  although  such  action  is  probably 
more  physical  than  chemical. 

Should  this  effect  be  desirable  with  any  particular  quality  of  stone,  it  is  easily 
obtained  by  using  gas  with  the  low  pressure  steam  or  moisture  endothermic;  such 


BURNING   LIME   AND   CEMENT 

1 


331 


Section  of  the  Duff  Kiln. 


Plan  of  Duff  Kiln  Plant. 


FIG.  168. 


FIG.  169.— Typical  Shaft  Lime  Kiln  showing  Runway  for  Charging  Limestone. 


332 


GAS   PRODUCERS 


gas  can  be  made  with  a  high  degree  of  saturation,  that  is  to  say,  with  from  eight- 
tenths  to  one  pound  of  water  per  pound  of  coal  gasified. 

The  following  installation  is  similar  to  that  of  the  National  Mortar  and  Supply 
Co.,  of  Gibsonberg,  Ohio,  which  was  furnished  in  connection  with  Duff's  Patent  Water 
Seal  Producers.  The  kilns,  four  in  number,  are  connected  with  the  producer  between 
lateral  headers.  They  are  10  ft.  in  diameter  outside  and  6  ft.  inside  of  brick-work  and 
are  25  ft.  high. 

Each  of  these  kilns  has  a  capacity  of  about  125  barrels  per  kiln  for  24  hours  and 
the  fuel  economy  approximates  6  Ibs.  of  lime  to  a  pound  of  coal,  the  coal  being  a  fair 
Pennsylvania  grade. 

This  economy  is  a  saving  of  practically  one-half  over  that  obtained  under  similar 
conditions  with  the  same  stone,  by  direct  firing.  By  increasing  the  height  of  the 
kilns  to  35  ft.  an  additional  capacity  of  25  barrels  per  kiln  per  day  could  be  obtained 
with  possibly  more  economic  fuel  consumption. 

Another  successful  lime  plant  in  operation  with  Duff  producers  is  that  of  the  Ohio 
and  Western  Lime  Company  of  Gibsonberg,  Ohio,  who  operate  with  a  high  degree  of 
economy  and  efficiency.  The  same  company  have  a  number  of  plants  in  satisfactory 
operation  in  connection  with  the  Bauxite  ores,  lime  roasters  and  rotary  kilns. 

Rotary  Lime  Kiln. — The  following  notes  are  made  upon  a  rotary  kiln  for  the 
production  of  lime.  Length  of  kiln  100  ft.  Diameter  of  kiln  6  ft.  Thickness  of 
lining  6-in.  fire-brick  for  first  60  ft.,  9-in.  fire-brick  for  balance  of  distance. 


FIG.  170. — Producer-fired  Rotary  Lime  Kiln. 

The  kilns  are  supported  by  three  bearings,  being  driven  by  the  center  bearing. 
Inclination  of  kiln  |  in.  to  the  foot.  Number  of  revolutions  of  kiln,  one  revolution 
in  2  minutes  and  10  seconds.  Size  of  producer,  10  ft.  diameter,  Morgan  type.  Total 
power  used  for  revolving  kiln,  conveyors,  crushers,  and  other  mechanical  devices, 
50  h.p. 

In  this  type  of  kiln  the  stone  is  changed  through  a  conveyor  into  the  crusher, 
where  under  the  Jones  patent  it  is  reduced  to  a  2-in.  mesh.  The  stone  is  then  carried 
the  length  of  the  kiln.  Period  of  calcination  about  3J  hours  per  unit  of  stone.  Maxi- 
mum temperature  of  lime  kiln,  2020°  F.  Temperature  of  gas  in  settling  chamber  or 
dust  separator  at  end  of  kiln,  630°  F.  These  gases  are  passed  through  a  boiler  and  their 
heat  recuperated  by  raising  steam. 


BURNING   LIME   AND  CEMENT 


833 


The  primary  and  secondary  air  for  the  manufacture  of  the  gas  and  its  combustion, 
respectively,  is  drawn  through  the  cooling  chamber  along  the  conveyor  and  up  through 
the  collecting  or  receiving  vat,  situated  at  the  base  of  the  kiln,  thereby  securing  a 
fair  degree  of  pre-heat.  The  yield  of  this  kiln  runs  from  5  to  6£  Ibs.  of  lime  per  pound 
of  fuel. 


FIG.  171. — Rotary  Kiln  Plant  of  the  New  England  Lime  Co.  under  Construction. 

German  Lime  Kilns. — German  gas-fired  lime  kilns  have  attained  an  economy  of 
25  to  50( '.•[  over  the  direct-fired  kiln.  That  is  to  say,  a  production  of  from  4  to  6  units 
of  lime  per  1  unit  of  fuel.  This  can  only  be  attained  by  utilizing  the  heat  of  the  cooling 
lime  in  the  pre-heating  of  the  secondary  air. 


FIG.  172. — Vertical  and  Horizontal  Sections  of  a  German  Gas-fired  Lime-kiln. 


334 


GAS   PRODUCERS 


FIG.  173. — Section  showing  Pressure-air  Nozzles  (a). 


FIG.  174. — View  of  German  Gas-fired  Lime-Kiln. 


BURNING   LIME   AND  CEMENT 


335 


Cement  Kilns. — In  the  manufacture  of  cement  where  producer  gas  is  burned  in 
rotary  kilns,  it  is  necessary  for  economic  work  to  recuperate  a  large  amount  of  sensible 
heat  from  the  incandescent  clinker.  This  may  be  done  by  passing  through  the  clinker 
the  secondary  air,  arid  temperatures  as  high  as  800°  F.  can  thus  be  obtained. 


FIG.  175. — Gas-fired  Rotary  Cement  Kiln. 

The  temperature  of  these  kilns  generally  run  from  2000  to  2700°  F.  which  can  be 
readily  obtained  with  this  degree  of  recuperation,  when  it  compares  very  favorably 
with  coal-dust  firing,  supplying  a  clean  finished  product. 

The  Eldred  Process  of  Cement  Clinkering. — The  following  outline  of  a  cement 
clinkering  gives  the  data  upon  which  a  maximum  thermal  efficiency  system  is  based. 
Although  this  system  is  as  yet  only  in  a  tentative  form,  the  data  herewith  given  is 
derived  from  practical  experiments  and  from  calculations  of  the  best  authorities  in 
this  country  and  in  Europe.  The  figures  therein  contained  may  therefore  be  taken 
as  representing  a  fairly  accurate  basis  of  computation. 

In  the  modern  practice  of  producing  Portland  cement  in  the  United  States,  it  is 
practically  all  burned  in  a  rotary  kiln  fired  usually  by  the  burning  of  a  flame  plume  of 
pulverized  coal  axially  with  the  kiln,  but  oil  and  natural  gas  are  sometimes  used.  The 
raw  materials  used  in  the  manufacture  may  be  divided  into  three  groups,  as 
fellows: 

First  Group. — This  consists  of  what  are  called  cement  rocks,  from  their  having 
been  formerly  used  in  the  manufacture  of  natural  cement.  These  consist  of  rocks 
having  nearly  the  composition  of  Portland  cement,  and  with  the  lime,  alumina,  and 
silica  already  in  combination  to  some  extent.  To  these  rocks  is  added  usually  enough 
limestone  to  produce  cement  of  the  proper  analysis  and  this  mixture  is  dried,  ground, 
and  fed  into  a  rotary  kiln. 

Second  Group. — In  this  may  be  placed  a  mixture  of  limestone  and  silicious  clay, 
dried  and  ground  and  fed  into  the  rotary  kiln.  In  burning  this  mixture,  the  water 


336  GAS   PRODUCERS 

of  hydration  must  be  dissociated  from  the  clay,  the  mixture  must  be  raised  to  the 
dissociation  temperature  of  limestone,  say  900  to  1000°  C.,  the  carbonic  acid  must  be 
then  driven  off  and  the  resulting  lime  and  baked  clay  brought  to  the  temperature  at 
which  sintering  takes  place,  say  1300°  C.  At  this  temperature  combination  of  the 
lime  with  the  silica  takes  place,  forming  among  other  compounds  tri-calcium  silicate 
(3CaO.Si02)  arid  di-calcium  aluminate  (2CaO.Al2O3),  which  are  considered  as  the 
active  substances  in  cement.  (See  U.  S.  Geol.  Survey  Report.) 

Third  Group.  —  This  is  marl,  which  is  finely  divided  calcium  carbonate,  being 
the  remains  of  sea  shells  or  fresh  water  shells,  and  with  this  is  mixed  enough  clay  and 
sand  to  give  the  proper  proportions  of  lime,  alumina,  and  silica;  this  mixture  is  ground 
wet  into  a  slurry  and  fed  into  the  rotary  kiln  in  a  semi-liquid  form  and  is  there  dried 
and  burned. 

In  the  mixtures  of  the  first  group  the  amounts  of  lime  combined  with  the  silica 
and  alumina  and  the  amount  combined  with  the  carbonic  acid  to  form  limestone,  are 
quite  variable,  so  that  the  amount  of  heat  necessary  to  produce  cement  from  this 
mixture  would  differ  in  each  case  and  cannot  be  accurately  determined  until  all  the 
elements  of  the  mixture  are  analyzed. 

In  the  third  group  the  amount  of  water  is  so  much  and  so  variable  that 
the  fuel  requirements  cannot  be  determined  until  the  amount  of  water  present 
is  known. 

In  the  second  group,  however,  the  constituents  are  assumed  to  be  pure,  and  these 
we  will  select  as  the  mixtures  on  which  the  hoat  determination  will  be  calculated.  We 
will  assume  that  the  theoretical  cement  produced  is  to  have  the  following  composition 
corresponding  writh  CasSiOs  and  Ca2Al205: 


Lime,  CaO  ......................................     68.25% 

Silica,  SiO2  ......................................      19  .  72% 

Alumina,  A1203  ..................................      11  .93% 

All  the  other  constituents  found  in  commercial  cement  are  accidental  impurities, 
and  it  is  well  settled  that  they  do  not  improve  the  cement,  and  most  of  them  must 
be  guarded  against  less  any  excess  impair  the  quality  of  the  product. 

To  produce  a  cement  of  this  quality  requires  that  the  following  ingredients  be 
used  in  the  proportions  given: 


Limestone,  CaCO3  ..............................   121.2  Kgs. 

Clay,  Al2O3.2SiO2.2H20  .........................     32.0  Kgs. 

Sand  ..........................................       4.8  Kgs. 


Total  weight  of  mix 158  Kgs. 


Therefore  158  kgs.  of  raw  mixture  will  make  100  kgs.  of  cement.     The  operation 
may  be  divided  into  two  stages,  and  the  heat  requirements  will  be  here  calculated' 


BURNING   LIME   AND  CEMENT  337 

for  the  two  operations  of  calcining  and  clinkering,  the  first  of  these  consisting  of 
heating  the  mixture  to  900°  C.  thus  dehydrating  the  clay  and  decomposing  the  lime- 
stone. , 

Calcining  Kiln. — The  heat  requirements  for  producing  calcines  are  as  follows: 
For  dehydrating  the  clay  there  will  be  required  1218  calories  per  gram  of  water  disso- 
ciated from  the  clay;  H20,  4.5  kgs. 

For  dissociating  CC>2  from  limestone  requires  1026  calories  per  kg.  of  CO2.  For 
heating  the  charge  it  will  be  assumed  that  the  specific  heat  of  the  mix  is  at  lower 
temperature,  about  0.25: 

158-4.5  =  153.5  kgs.;  153.5 X0.25X  900  =  34.537  calories  for  heating. 

4.5X1218=   5.480  calories  for  dehydrating  clay. 
121  kgs.  CaC03  =  53.2  kgs.  CO2;  53.2X1026  =  54.600  calories  for  dissociating  limestone. 


Total 94.617  calories  for  producing  calcines. 

For  sintering,  the  heat  requirements  are  very  much  less;  in  fact  the  exothermic 
reactions  produce  one-third  as  much  heat  as  is  absorbed  in  heating  the  calcines  to  the 
sintering  temperature,  hence  the  advantages  of  dividing  the  process  into  two  stages. 
The  heat  of  combination  of  lime  with  silica  and  alumina  in  cement  does  not  seem  to 
have  been  accurately  determined  by  Le  Chatelier,  who  determined  that  in  the  combina- 
ation  of  3CaO.Al203.2SiO2  that  there  were  150  cals.  developed  per  unit  of  Al2O3.2SiO2 
and  as  the  silica  and  alumina  exist  in  about  that  ratio  in  the  cement,  their  sum  multi- 
plied by  150  cals.  will  give  the  heat  produced. 

In  heating  the  calcines  from  900  to  1300°  C.  their  specific  heat  is  assumed  to  be 
0.30,  therefore: 

100 X 0.3  X 400  (1300  -900)  =  12.000  calories  absorbed  by  clinker. 
31.65  (SiO2  and  A12O3)  X150=   4.747  calories  produced. 


Difference 7 . 253  calories  absorbed  from  fuel. 

The  total  heat  units  in  the  clinker  as  discharged  would  be  as  follows: 

100  kgs.  X  0.3X1300  =  39,000. 

The  above  represents  the  heat  requirements,  provided  that  the  combustion,  gases 
left  the  kilns  cold  and  the  carbonic  acid  gas  from  the  limestone  left  the  kiln  at  the  tem- 
perature of  dissociation.  Practical  working  tests  with  a  gas-fired  rotary  kiln  100  ft. 
long  X6  ft.  in  diameter,  burning  limestone  crushed  to  2  in.  size,  such  limestone  contain- 
ing 98%  CaCOs,  have  shown  that  it  is  safe  to  assume  an  output  of  six  parts  of  lime 
to  one  part  of  good  gas  coal.  Therefore  66  kgs.  of  lime  would  require  11  kgs.  of  fuel, 
and  as  there  is  66  kgs.  of  lime  in  100  kgs.  of  cement,  11  kgs.  of  coal  would  calcine  all 


338  GAS    PRODUCERS 

of  the  lime  to  produce  100  kgs.  of  cement.  There  remains  only  the  heat  requirement 
for  bringing  33  Ibs.  of  Si02  and  A12O3  to  the  required  temperature  at  which  the  lime  is 
formed. 

SiO2  +  Al2O3  =  33  kgs.;  33X0.25X900°  C.  =  7425  cals., 

which  would  be  equivalent  to  not  more  than  1  kg.  of  coal  per  100  kgs.  of  calcines, 
therefore  the  requirements  for  the  calcining  kiln  will  be: 

1 1      kgs.  of  coal  for  heat  to  produce  66  kgs.  of  lime. 
1      kg.  of  coal  for  heat  to  raise  temperature  of  clay. 
0 . 5  kg.  of  coal  allowance  for  heat  losses  in  heating  up  clay. 


12.5  kgs.  coal  per  100  kgs.  calcines  or  1  part  coal  to  8  parts  calcines. 

Clinkering  Kiln. — For  clinkering,  estimating  that  the  calcines  are  discharged 
directly  from  the  primary  kiln  in  the  clinker  kiln  at  900°  C.,  and  are  therein  heated 
to  1300°  C.,  a  range  of  400°  rise  in  temperature,  100X0.3X400  =  12.000  calories 
absorbed. 

The  clinkering  operation  is  exothermic.  Since  Le  Chatelier  has  determined  that 
150  calories  are  evolved  per  unit  of  combined  SiO2Al203,  therefore  31.65  kgs.  (com- 
bined silica  and  alumina)  X 150  =  4747  calories. 

Subtracting  this  from  the  12,000  calories  absorbed  by  the  calcines  in  the  clinkei- 
ing  kiln  there  remains  7253  cals.  per  100  kgs.  to  be  furnished  by  the  fuel.  This  represents 
slightly  less  than  1%  fuel  for  clinkering. 

Assuming  that  180  tons  are  to  be  clinkered  per  day  in  one  clinkering  kiln,  180 
tons  =18,000  kgs.  divided  by  100  =  1800  kgs.  coal  or  1%.  There  remains  39,000  cals. 
in  the  discharged  clinker  and,  assuming  that  one-third  of  this  heat  can  be  taken  up 
by  cooling  with  air  and  supplied  to  the  primary  or  calcining  kiln,  13,000  kgs.  would 
be  afforded  per  100  kgs.  or  H  kgs.  coal,  or  1.5%,  which,  subtracted  from  12.5  kgs. 
coal  used  in  calcining,  gives  11  kgs.  or  11%  fuel,  or  1  part  of  coal  to  9  parts  of 
calcines. 

Assuming  an  efficiency  of  only  25%  in  the  clinkering  kiln,  or  4  kgs.  per  100, 
1800  kgs.  X4  =  7200  kgs.  This  would  be  4%  of  the  fuel  consumption,  or  4  kgs.  per 
100,  which,  added  to  the  11  required  for  calcining,  equals  15  kgs.  per  100  or  15%,  or 
1  part  of  coal  to  6.6  parts  of  cement. 

A  regenerative  system  is  capable  of  utilizing  84.2%  of  the  total  heat  of  the  gas 
and  the  producer  should  have  an  efficiency  of  80%,  thus  giving  64%  efficiency  for 
the  combination  of  the  producer  and  kiln,  not  allowing  for  radiation  loss.  I  believe 
that  it  would  be  safe  to  assume  50%  efficiency  for  the  clinkering  kiln  outfit,  allow- 
ing 14%  for  loss  by  radiation.  If  this  result  is  realized  the  process  would  yield 
7.69  kgs.  of  cement  for  each  keg  of  coal  consumed.  This,  as  will  be  seen,  effects  a 
saving  of  more  than  one-half  of  the  present  fuel  consumed  under  average  direct  firing 
practice  or  an  increased  efficiency  of  over  100%. 

The  Eldred  Process  of  cement  burning  is  as  yet  in  a  more  or  less  tentative  state, 
and  inasmuch  as  its  discussion  embodies  pro  and  con  practically  all  the  principles 


BURNING   LIME    AND   CEMENT  339 

involved,  and  such  a  discussion  necessarily  involves  a  recapitulation  of  the  elementary 
data,  it  has  been  thought  worth  while  to  insert  it  here. 

The  general  principles  claimed  by  Mr.  Eldred  are  undoubtedly  correct,  there 
being  however,  certain  variables  relative  to  the  fuel  and  materials  used.  Also  there 
is  a  question  in  the  mind  of  the  writer  as  to  the  possibility  or  practicability  of  the  use 
of  flue  gases  in  this  process. 

Should  they  be  used,  their  confining  limits  must  be  along  the  following  lines: 

(a)  It  is  questionable  whether  it  is  well  for  high  temperature  work  to  use  CC>2 
or  the  resultant  products  of  combustion  as  an  endothermic  agent  by  reason  of  the 
low  flame  temperature  derived  from  the  combustion  of  the  gas  consequent  upon  its 
small  calorific  value.  For  while  hydrogen  is  unsuitable  as  a  power  gas,  it  has  a  high 
flame  temperature  and  displaces  about  twice  its  own  volume  of  nitrogen  in  a  constit- 
uent gas,  hence  its  presence  is  highly  valuable  in  an  operation  of  this  kind. 

(6)  Again  as  to  the  obtaining  of  a  voluminous  gas  through  the  use  of  secondary 
dilution  or  retarding  of  the  flame,  this  again  is  only  obtained  at  the  expense  of  flame 
temperature.  Hence  it  will  be  manifest  that,  in  order  to  obtain  its  dilution,  it  will 
be  necessary  to  considerably  "  boost  "  the  flame  temperature  by  a  high  degree  of 
regeneration  and  p  re-heating  of  the  elements  of  combustion. 

When,  however,  it  is  considered  that  such  pre-heating  is  merely  a  function  of  the 
original  flame  temperature,  the  question  becomes  cyclic  and  must  be  determined  by 
absolute  experiment. 

It  is  of  course  a  fact  that  the  voluminous  or  elongated  flame  function  of  retarded 
or  prolongated  combustion,  due  to  the  dilution  of  the  air,  has  been  successfully  used 
in  connection  with  the  manufacture  of  cement  in  rotary  kilns,  but  it  must  also  be 
remembered  that  the  combustion  in  this  case  was  that  of  powdered  fuel  possessing  a 
third  greater  flame  temperature  than  that  possessed  by  ordinary  fuel  gas. 

A  general  outline  of  the  Eldred  process,  which  is  interesting  particularly  as  it 
reflects  the  subjects  of  two-stage  calcining  and  complete  heat  recuperation,  is  as  follows: 

It  has  been  the  modern  practice  to  burn  cement  with  a  long  blast-flame  in  a 
rotary  kiln,  but  to  employ  the  same  flame  for  both  the  calcining  and  sintering  or  final 
vitrifying  of  the  material,  although  the  temperature  requirements  are  very  different 
in  the  two  cases,  the  calcining  step  or  expulsion  of  carbon  dioxide  and  water  being 
an  endothermic  process,  requiring  a  comparatively  low  temperature  (about  1200  to 
2000°  F.)  and  a  large  volume  of  hot  gases,  while  the  clinkering  reaction  absorbs  but  little 
heat  and  is  really  exothermic,  and  should  take  place  under  high  temperature  conditions 
(about  2500°  F.  or  higher).  It  is  very  difficult  in  practice  with  a  single  flame  to 
obtain  and  maintain  a  proper  balance  between  these  two  effects,  so  that  in  the  one  case 
the  calcining  shall  be  sufficiently  performed  before  fusion  sets  in  and  in  the  other  case 
the  desired  degree  of  fusion  shall  be  effected  before  the  material  leave  the  kiln  or  passes 
beyond  the  influence  of  the  clinkering  flame.  In  practice  the  kiln-tender  attempts 
to  control  matters  by  regulating  the  speed  of  the  cylinder  and  the  quantity  of  cement 
material  fed  in  at  the  upper  end  per  unit  of  time;  but  this  requires  the  greatest  skill, 
in  spite  of  which  the  feed  or  travel  of  the  material  will,  on  the  one  hand,  often  be  too 
slow  in  respect  to  the  temperature  of  the  flame,  which  means  that  too  much  heat  is 
devoted  to  clinkering  and  too  little  to  calcining,  giving  premature  fusion  of  under- 
calcined  material,  while  on  the  other  hand  if  the  speed  is  too  fast  the  clinkering  zone 


340  GAS    PRODUCERS 

retreats  toward  the  discharge  end  and  too  much  of  the  heat  goes  into  calcining  and 
too  little  into  clinkering,  so  that  the  cement  may  be  under-fused.  The  flow  of  the 
material  through  the  calcining  zone  can  be  regulated  only  by  varying  the  flow  through 
the  clinkering  zone.  When  variations  in  the  composition  of  the  cement  material 
are  encountered,  a  change  in  the  feed  or  in  the  flame  must  often  be  effected,  and  this 
will  frequently  destroy  the  proper  balance  of  operation?  in  the  kim. 

In  the  method  under  discussion,  two  or  more  separate  flames  are  employed  for 
the  calcining  and  clinkering  operations,  respectively,  and  each  flame  is  regulated  to 
a  temperature  corresponding  to  the  operation  in  which  it  is  engaged  instead  of,  as 
formerly,  trying  to  regulate  one  flame  for  both  operations.  The  two  steps  of  the  burning 
process  are  preferably  carried  on  in  chambers  more  or  less  separate,  one  of  which  may 
deliver  material  into  the  other  and  maintain  the  heating  influences  in  the  two  opera- 
tions substantially  independent.  The  conditions  of  combustion  and  rate  of  feed  may 
then  be  independently  regulated  for  each  stage  of  the  process,  and  the  delicate  balance 
of  operations  no  longer  exists. 

It  has  been  found  that  one  of  the  most  important  consequences  of  this  method 
is  that  it  now  becomes  possible  to  employ  a  profitable  and  dustless  fuel,  such  as  a 
producer  gas,  thus  avoiding  the  expense  and  danger  of  powdered  coal,  for  by  carying 
on  the  two  stages  in  separate  chambers  it  is  possible  to  regenerate  or  recuperate  the 
materials  of  combustion  and  obtain  a  very  high  temperature  in  the  clinkering  chamber, 
while  also  employing  a  flame  in  the  calcining  chamber  especially  suited  to  the  calcining 
operation.  Heretofore  regeneration  has  not  been  found  practicable,  because  the  gases 
at  the  upper  end  of  the  kiln  would  be  so  full  of  dust  as  to  clog  the  regenerators  and  so 
far  cool  down  in  consequence  of  the  absorption  of  their  heat  by  the  materials  under- 
going the  endothermic  calcining  operation  as  to  be  of  little  use  in  obtaining  a  high 
clinkering  temperature. 

In  the  calcining  stage,  the  gas  and  air  may  be  used  with  or  without  regeneration, 
while  in  the  clinkering  stage  the  gas  or  air,  or  both,  are  preferably  regenerated,  so  as 
to  obtain  a  very  high  temperature  and  great  economy  in  fuel.  The  gases  for  heating 
the  regenerators  for  the  clinkering  stage  are  abstracted  from  the  clinkering  chamber 
where  they  are  very  hot  and  comparatively  free  from  dust.  Thus  for  clinkering,  the 
fuel  heat  is  used  in  a  very  high  temperature  form  and  only  a  small  quantity  of  gases  is 
required,  while  for  calcining  the  volume  of  gases  is  perferably  large  and  their  temper- 
ature low.  The  calcining  takes  a  longer  time  than  the  clinkering,  and  for  that  stage  a 
producer  gas  flame  of  moderate  temperature  and  large  volume  is  well  adapted  and  is 
preferably  carried  well  down  into  contact  with  the  material.  The  temperature  of 
the  calcining  flame,  however,  may  be  raised  to  absorb  more  of  this  heat  by  passing 
more  material  in  a  given  time.  The  gases  at  the  end  of  this  stage  are  hot  enough  to 
yield  a  moderate  regenerating  heat  for  the  calcining  flame  if  it  be  desired  to  carry  a 
hotter  flame  than  one  unregenerated.  Since  the  chambers  may  each  be  made  shorter 
than  the  usual  length  of  a  cement-kiln  and  the  strong  blast  current  required  to  keep 
powdered  fuel  in  suspension  is  no  longer  necessary,  a  weaker  blast  may  be  used  and 
less  dust  produced  in  the  calcining  chamber. 

The  operation  in  the  calcining  chamber  is  advantageously  carried  to  a  point  at  which 
incipient  fritting  or  softening  of  the  material  occurs,  so  that  it  enters  the  clinkering 
chamber  practically  free  from  dust. 


342  GAS   PRODUCERS 

. 

Among  other  advantages  which  may  be  named  are  the  ability  to  force  the  feed, 
if  necessary,  especially  in  the  clinkering  chamber,  enabling  a  smaller  din ke ring  kiln 
to  handle  the  material  and  enabling  several  calcining-kilns  in  parallel  to  feed  a  single 
clinkering  kiln.  Conversely  several  clinkering  chambers  might  take  the  product  of 
a  single  calcining  chamber. 

Since  there  is  a  relatively  moderate  temperature  in  one  chamber  and  a  relatively 
high  temperature  in  the  other  with  no  intermediate  temperature,  the  formation  of 
"rings"  adhering  to  the  lining  of  the  kiln  is  avoided.  The  material  is  accessible 
between  stages  for  withdrawing  samples  for  the  purposes  of  analysis.  Wear  and  tear 
due  to  sudden  changes  in  temperatures  and  to  widely  different  temperatures  in  different 
parts  of  the  same  chamber  is  avoided. 

The  material  to  be  calcined  is  fed  in  at  5,  passes  through  the  rotary  kiln  2, 
drops  from  its  end  by  a  chute  into  rotary  kiln  3  of  higher  temperature  and  from 
its  end  by  a  chute  to  a  platform  to  pre-heat  the  entering  air,  and  is  discharged  by 
a  conveyor.  The  gas  is  made  in  the  producer  1  and  sent  out  by  two  pipes,  one 
to  the  lower  end  of  kiln  2,  the  other  to  the  reversing  valve  and  through  flues  7 
and  checker  brick.  The  air  is  delivered  by  a  fan  shown  at  the  left  hand,  one 
branch  passing  down  to  the  calcined  clinker  platform,  the  other  going  through  recup- 
erator pipes  9  in  the  stack  and  thence  to  the  lower  end  of  kiln  2.  The  baffle 
chambers  4a  and  46  intercept  the  dust  and  the  water  tube  boiler  10  makes  steam 
for  the  producer  blast. 

In  the  operation  of  this  process  the  raw  material  is  introduced  into  the  kiln  at  5 
and  is  there  subjected  to  a  calcining  flame  by  the  combustion  of  the  producer  gas  with 
the  air  admitted  into  the  lower  part  of  the  kiln,  as  above  indicated.  A  long  voluminous 
flame  is  here  produced,  giving  that  "  soaking  "  heat  or  slow  heat  undulation  requisite 
for  the  dissociation  from  the  material  of  the  carbon  dioxide  chemically  combined  with 
the  lime  and  magnesia.  The  material  which  passes  through  the  chamber  2  is  freed 
by  the  application  of  this  specifically  calcining  flame  from  its  carbon  dioxide  and 
falls  through  the  chute  into  the  clinkering  kiln  3.  Here  a  high  temperature  is  main- 
tained by  means  of  the  regenerative  system  employed,  the  material  being  maintained 
at  or  rapidly  brought  to  the  temperature  at  which  the  clinker  forming  exothermic 
reaction  occurs.  The  material  is  finally  discharged  into  the  clinker  cooler  over 
which  a  current  of  air  is  caused  to  flow.  As  soon  as  the  material  is  sufficiently  cooled 
it  may  be  ground  to  the  fineness  required. 

Various  apparatus  may  be  employed  to  carry  out  the  process.  For  example 
instead  of 'a  rotary  kiln  for  clinkering,  a  furnace  equipped  with  a  shaking  hearth  may 
be  employed.  Different  kinds  of  fuel  may  be  employed,  suited  to  the  particular 
character  of  furnace,  although  producer  gas  is  preferred  for  the  reasons  already  stated. 

In  operating  the  furnace  the  transition  point  between  the  calcining  and  clinkering 
stages  may  to  some  extent  shift  from  one  chamber  to  the  other,  it  being  one  of  the 
advantages  of  the  invention  that  great  latitude  of  operation  is  possible  and  little  skill 
required;  where  formerly  the  reverse  was  true.  Under  some  conditions  it  may  be 
found  desirable  to  perform  the  calcining  and  clinkering  at  different  times,  that  is 
non-continuously.  This  invention  enables  this  to  be  effected.  The  main  purpose  of 
passing  the  calcines  directly  into  the  clinkering  kiln  is  of  course  to  conserve  the  heat 
of  the  calcines. 


BURNING   LIME   AND   CEMENT  343 

It  will  be  understood  that  this  invention  does  not  claim  to  have  originated  the 
separate  performance  of  the  calcining  and  clinkering  operations  in  cement  manufacture; 
but  it  is  the  first  to  utilize  the  two-stage  method  with  reference  to  the  regulation  and 
control  of  temperatures  by  internal  heating  in  reverberative  chambers  with  special 
fuels,  and  more  particularly  with  regard  to  the  advantages  of  using  producer  gas  and 
other  weak  gases  in  both  or  either  of  the  stages  and  successfully  regenerating  the 
materials  of  combustion. 


CHAPTER   XV 
PRE=HEATINQ  AIR 

Blast  Stoves. — In  a  general  way,  with  the  average  conditions  as  they  obtain 
throughout  the  country,  with  lower-priced  fuel  adapted  for  heating  air  in  the  U-pipe 
stove  for  pre-heating  blast,  as  compared  with  the  high-priced  coke  that  must  be  used 
in  the  blast  furnace,  air  may  be  heated  as  cheaply,  pound  for  pound,  to  a  temperature 
of  800  or  900°  F.  in  a  well-designed  stove  as  in  the  smelting  zone  of  the  blast  furnace. 

U-pipes  of  cast  iron  will  stand  a  long  while  at  a  low  red  heat  (about  800°  F.)  with- 
out distortion  or  other  damage,  if  properly  designed  and  made  of  suitable  material. 
Any  number  of  sections,  consisting  as  above  of  four  series  to  the  section  and  6,  7,  or  8 
pipes  in  each  series,  are  attached  or  coupled  together,  through  flanges  on  the  mains, 
to  make  a  stove  of  any  size  required.  The  elbows  and  flanges,  which  serve  to  couple 
the  U-pipes  together,  as  also  the  rectangular  main  blast  pipes  of  the  stove,  which  serve 
respectively  to  conduct  the  cold  air  into  the  various  series  of  U-pipes  and  the  hot  air 
out  of  them,  and  to  which  the  several  series  are  connected  by  flanges,  are  rectangular, 
of  suitable  size,  three-quarters  of  an  inch  thick,  rest  on  the  end  walls  of  the  heating 
chamber,  and  are  all  above  it.  These  mains  are  usually  bricked  in,  or  else  covered 
with  asbestos  cement  to  prevent  loss  of  heat  by  radiation.  There  are  flanges  below 
the  elbows  on  the  U-pipe,  as  high  up  as  practicable  and  completely  encircling  them, 
and  on  these  flanges  are  placed  fire  tiles  of  suitable  form,  which  constitute  the  roof 
or  top  of  the  heating  chamber,  down  into  which  project  the  main  portion  of  the  U-pipe 
for  heating.  The  roof  of  the  heating  chamber,  including  the  top  elbows  of  the  U-pipcs, 
are  usually  covered  with  ashes  a  foot  or  a  foot  and  a  half  deep,  to  prevent  heat  radia- 
tion from  the  roof  and  from  the  top  elbows. 

This  system  of  covering  and  insulating  the  top,  and  thus  conserving  heat  that 
would  otherwise  be  radiated  into  the  atmosphere  and  lost,  is  the  best,  simplest,  and 
cheapest  possible,  admitting  of  ready  access  to  the  flanged  elbows  where  the  U-pipes 
are  bolted  together. 

All  joints  are  machined  true,  and  provided  with  asbestos  gaskets,  and  are  thus 
capable  of  being  always  screwed  up  air  tight,  and  must  always  be  so,  for  a  leaky  stove 
entails  great  loss.  Every  joint  and  every  bolt  in  the  stove  is  readily  accessible  from 
the  outside,  and  no  joint  or  bolt  is  exposed  to  the  fire  or  to  the  heat  of  the  heating 
chamber. 

U-pipes  can  be  detached,  taken  out  when  necessary  and  replaced  with  new,  with- 
out drawing  the  fires  or  cooling  the  stove,  other  than  to  close  all  draft  doors  tight  and 
shut  off  the  blast.  In  case  of  necessary  repairs,  the  cold-air  blast  is  turned  off  the 

344 


PRE-HEATING   AIR 


345 


stove  and  directly  into  the  blast  furnace.  A  burned-out  U-pipe  can  be  taken  out, 
a  new  pipe  put  in,  and  the  air  blast  turned  through  the  stove  again  in  an  hour,  without 
cooling  down  the  stove. 

Expansion  and  contraction  strains  are  so  compensated  that  no  pipe  or  other  part 
of  a  U-pipe  stove  can  ever  fail   by  reason   of  such   strains.     A  U-pipe  stove,  properly 


FIG.  177.— Section  of  Blast  Pre-heater  Pipe. 

managed,  is  as  durable  as  the  average  smelting  furnace.  The  only  possible  danger  is 
in  burning,  and,  with  the  present  system  of  constructing  the  heating  chamber  and  pro- 
tecting all  U-pipes  from  the  direct  action  of  currents  of  flame  and  heat  impinging 


FIG.  178.^Longitudinal  Vertical  Section  of  U-pipe  Hot-blast  Pre-heater. 

upon  them,  they  never  should  burn,  and  never  can  do  so  except  through  the  grossest 
carelessness. 

U-pipes  must  not  be  subjected  to  the  direct  action  of  violent  currents  of  flame 
and  incandescent  products  of  combustion  from  the  reverberatory  roofs  of  the  fire 
boxes  that  would  melt  or  burn  them. 


346 


GAS   PRODUCERS 


Practically,  air  heats  very  little  by  radiation,  but  by  contact  with  heated  surfaces, 
and,  for  this  reason,  to  heat  air  economically,  ample  heating  surfaces  must  be  provided. 
To  increase  the  heating  surfaces  of  U-pipes,  they  are  sometimes  cast  with  longitudinal 
ribs  on  the  inside,  as  shown  in  detail  in  the  drawing. 

Iron  is  a  very  active  conductor  of  heat,  and,  projecting  inward  from  the  body  of 
the  pipes,  as  they  do,  these  ribs  become  heated,  and  the  air  coming  in  contact  with 
them,  as  well  as  with  the  balance  of  the  inside  surface  of  the  U-pipes,  the  area  of  the 
heating  surface  and  hence  the  efficiency  of  the  stove,  is  very  greatly  increased,  doubled 
in  fact.  U-pipes  of  cast  iron  will  stand  far  more  heat  without  distortion  or  other 
damage  than  pipes  made  of  steel  or  wrought  iron. 


FIG.  179.— U-pipe  Hot-blast  Stove. 

The  heating  surface  necessary  for  heating  an  air  blast  to  600°  F.  may  be  taken  as 
.4,  and  to  800°  .5  of  a  square  foot  for  each  cubic  foot  of  air  to  be  heated  per  minute. 
The  extreme  ultimate  velocity  of  heated  air  on  leaving  the  stove  and  in  the  pipes  to  the 
furnace  should  not  exceed  5000  ft.  per  minute. 

Air  expands  0.002036  of  its  volume  for  each  Fahrenheit  degree  added;  therefore, 
when  heated  to  600°  F.  from  60°  normal  atmosphere,  its  volume  has  become  2. 1  times 
its  original  volume,  and  hence  all  pipes  and  tuyeres  must  have  more  than  double  the 
area  required  for  cold  air  of  given  amount  in  weight. 

Sturtevant  Pre-heater.— This  pre-heater  will  absorb  from  1  to  1.25  B.T.U.  per 
degree  mean  difference  between  the  temperature  of  gas  and  air  per  hour  per  square 
foot  of  heating  surface,  the  temperature  of  the  gas  being  about  500  or  600°  F..,  and 


PRE-HEATING   AIR 


347 


the  temperature  of  the  air  entering  the  heater  being  100°  F.  Of  course,  with  a  higher 
temperature  of  gas,  say,  between  1000  and  1500°  entering  the  heater,  the  air  entering 
the  heater  100°  F.  or  less,  the  absorption  would  be  between  1.5  and  2  B.T.U. 


T 


FIG.  180. — Sturtevant  Air  Pre-heater  Plant  (Elevation,  Plan  and  Cross-section.) 

Under  the  former  conditions,  the  Sturtevant  Co.  suggest  the  use  of  the  following 
formula  for  estimating  purposes: 


348 


GAS   PRODUCERS 


FIG.  181. — Air  Pipes  ana  Scrapers  to  Remove  Flue  Dust. 


PRE-HEATING   AIR  349 

Where  T  =  the  total  heat  transmitted  or  absorbed,  1.25  is  the  factor;  H  is  the  heating 
surface  in  square  feet;  G  is  temperature  of  gas  entering  air  heater;  g  the  temperature 
of  gas  leaving  the  air  heater;  A  is  the  temperature  of  the  air  leaving  the  air  heater, 
a  the  temperature  of  air  entering  the  air  heater.  The  velocity  of  air  flow  in  the  above 
is  assumed  to  be  approximately  2000  ft.  per  minute. 

The  advantages  claimed  for  the  heater  over  that  of  other  types,  are:  The  pipes 
are  arranged  in  staggered  rows,  instead  of  straight  rows;  there  are  no  gaskets  in  the 
gas  chamber;  the  heater  can  be  easily  connected  up  in  several  different  ways,  and 
frr  different  volumes  of  air;  it  can  be  made  up  in  sections  of  a  size  that  can  be  easily 
transported  and  installed;  there  are  baffle  plates  on  each  side,  also  in  the  center,  in 
order  to  give  accessibility  to  all  parts  of  the  apparatus;  the  driving  shaft  runs  length- 
wise of  the  apparatus,  which  requires  a  less  number  of  driving  heads,  and  less  power 
to  operate  the  scraper  mechanism. 


FIG.  182. — Passage  of  Gases  among  Straight  Rows  and  Staggered  Pipes. 

Green  Air  Heater. — This  heater  consists  of  a  group  of  vertical  cast-iron  tubes, 
9  ft.  long  between  the  headers  and  3|  ins.  internal  diameter.  These  tubes  are  forced 
by  a  hydraulic  press  into  top  and  bottom  boxes  to  form  six-tube  units.  These  units, 
or  sections,  are  assembled  side  by  side.  The  blow-up  gases  from  the  superheater  of 
a  water  gas  set,  for  example,  pass  in  among  the  tubes,  while  at  the  same  time  the  air 
supply  for  the  generator  is  forced  through  the  tubes  by  a  blower  and  take  up  heat 
from  the  gases,  returning  it  to  the  generator.  The  result  is  that  it  is  not  necessary 
to  blow  the  generator  so  long  to  bring  it  up  to  the  required  temperature  and  not  so 
much  fuel  is  required  in  the  blowing-up  process,  with  a  resulting  saving  in  the  present 
case  of  about  one-fifth  of  the  fuel  required  for  the  generators.  The  outsides  of  the 
tubes  are  kept  clean  of  soot  by  automatic  scrapers,  which  travel  slowly  up  and  down. 

The  net  result  is  that  there  was  an  average  saving  of  about  17.3%  of  generator 
coal  for  this  period  of  three  months,  with  a  maximum  saving  of  19.8%  in  June.  As  the 
monthly  output  runs  at  about  5,000,000  cu.ft.  of  gas,  and  as  on  an  average  8  Ibs.  of 
coal  per  1000  cu.ft.  of  gas  were  saved,  the  monthly  saving  of  coal  amounts  to  20  tons. 

Triple  Recuperation. — As  an  application  of  the  triple  recuperation  of  the  gas, 
secondary  air  and  primary  air,  the  system  of  A.  A.  Queneau  is  described  in  "  Industrial 
Furnaces,"  by  E.  Damour  and  A.  L.  Queneau.  The  apparatus  has  the  ordinary 


350 


GAS   PRODUCERS 


How  the  Green  Air 
Heater  or  Green  Fuel 
Economizer,  or  both,  are 
installed  to  recover  the 
waste  heat  from  the  stack- 
valve  gases. 


FIG.  183.— The  Green  Fuel  Economizer  in  Poughkeepsie  (N.  Y.)  Gas  Works,  where  it  is  saving  25% 

of  the   boiler  fuel. 


PRE-HEATING   AIR 


351 


Plan  of  New  Haven  (Conn.) 
Gas  Works,  showing  Green  Fuel 
Economizer  fitted  to  three  8-ft. 
U.  G.  I.  sets. 


Cross  -  sectional  Elevation  New 
Haven  Gas  Works.  This  Economizer 
supplies  the  boilers  with  water  at  a 
temperature  of  340  to  350°  F.,  saving 
25%  of  the  boiler  fuel. 


FIG.  184. — Air  Pre-heater  on  Water-gas  Machine. 


352 


GAS   PRODUCERS 


Siemen's  chambers  for  the  gas  and  secondary  air,  with  a  single  chamber  of  the  parallel 
counter-current   type   for  the   primary  air.     Usually   the   waste   products   leave   the 


FIG.  185. — Air  Pipes  and  Scrapers  on  Green  Pre-heater. 

Siemens  chambers  on  their  way  to  the  stack  at  a  temperature  which  allows  the  use 
of  cast-iron  pipes  for  the  recuperator.  In  case  of  high  temperatures  a  fire-brick 
recuperator  is  used. 

The  primary  air  recuperator  is  designed  so  that  the  waste  products  leave  it  at  a 


— — —  \  "••""••"  •'•'•", 

V///////777.  WJ////SS/SS/S///S/S 


FIG.  186. — Recuperation  of  Primary  Air,  Secondary  Air,  and  Gas — Queneau  System. 

temperature  of  about  200°  C.,  a  temperature  necessary  for  an  efficient  draught  in  the 
stack.  The  primary  air  is  forced  through  the  recuperator  by  means  of  a  positive 
blower,  while  the  heated  air  is  led  to  the  producer  through  a  brick-lined  flue.  In  order 
to  utilize  the  calories  of  the  primary  air  to  the  best  advantage,  without  endangering 


PRE-H EATING   AIR  353 

the  producer,  the  primary  air  meets  a  system  of  water-sprays  (the  steam  injector 
being  entirely  dispensed  with).  The  vaporization  of  the  water  injected  is  obtained 
wholly  at  the  expense  of  the  recuperated  waste  heat  (doing  away  with  the  boiler  plant). 
By  injectng  the  water  in  liquid  form  in  the  producer  and  obtaining  its  vaporization 
thereby,  the  fire  zone  of  the  producer  is  cooled  more  efficiently  than  by  steam  injection. 
The  amount  of  injected  air  and  water  can  be  varied  independently  at  will,  since  they 
are  not  interdependent,  as  in  the  case  of  the  steam  injector.  The  use  of  the  parallel 
counter-current  system  for  the  primary  air  does  away  with  the  complications  of  a  third 
set  of  valves.  The  regulation  of  the  temperature  of  the  primary  air  recuperator  is 
automatically  obtained  by  the  regulation  of  the  temperatures  in  the  Siemens  chambers. 
Two  conclusions  may  be  noted: 

1.  The  very  high  efficiency  of  furnaces  wth  triple  recuperation. 

2.  The  very  small  influence  of  the  ruling  temperature  on  the  heat  utilization. 
This  system  of  recuperation  is,  then,  particularly  suited  to  high  temperatures; 

its  use  would  result  in  a  fuel  economy  of  10%  over  that  of  the  Siemens  regeneration 
furnace. 

There  is  a  case  where  the  use  of  triple  recuperation  would  give  an  economy  even 
greater  than  10%;  it  is  in  its  application  to  industrial  operations  in  which  the  waste 
products  consist  of  the  products  of  combustion  of  the  fuel,  and  of  gases  liberated  by 
the  materials  under  treatment  in  the  hearth,  that  is,  water  vapor,  carbon  dioxide, 
sulphurous  dioxide,  etc.  Usually  the  calories  carried  by  these  gases  would  be  utterly 
lost,  since  the  products  of  combustion  of  the  fuel  have  higher  thermal  capacity  than 
the  recuperating  gases.  In  the  case  of  triple  recuperation  the  contrary  is  true,  and 
therefore  these  extra  calories  can  be  brought  back  to  the  hearth. 

Glass  furnaces  present  the  typical  example  of  this  supplementary  recuperation. 
The  materials  charged  in  the  furnace  carry  as  much  as  45%  of  volatile  products;  the 
coal  required  for  the  fusion  of  the  glass  wreighs  about  60%,  of  the  weight  of  the  fused 
glass.  The  mass  of  the  volatile  products  is,  therefore,  mathematically  speaking,  a 
quantity  of  the  same  order  as  that  of  the  products  of  combustion  of  the  fuel.  The 
ratio  of  the  masses  may  be  as  high  as  ^,  corresponding  to  a  loss  of  ^  of  the  available 
calories.  The  recuperation  of  these  lost  calories  added  to  the  increased  economy 
resulting  from  triple  recuperation  proper,  would  bring  an  increase  of  15%  in  the  fuel 
efficiency  by  the  application  of  this  system  to  glass  furnaces. 


,  CHAPTER  XVI 

THE    DOHERTY  COMBUSTION    ECONOMIZER 

THE  success  of  this  apparatus  is  due  to  two  features: 

1.  The  elimination  of  clinkers  due  to  the  ability  of  the  bench  to  use  a  large 
volume  of  flue  gas  as  an  endothermic  agent.     The  large  amount  of  the  volume  sub- 
tending general  and  thorough  saturation  of  the  fuel  bed. 

2.  High  fuel  economy  due  to  the  same  large  volume  of  flue  gas  being  converted 
to  fuel  gas  through  the  reaction  or  regeneration  of  the  fuel  bed. 

The  large  volume  (about  50%  of  the  total  flue  gas)  above  stated  is  made 
possible  only  on  account  of  the  high  temperature  at  which  the  flue  gasses  are  returned 
from  the  outlet  of  the  bench,  it  being  a  fact  as  before  stated,  that  the  endothermic 
powers  of  CO2  diminish  with  temperature  and  hence  a  large  quantity  at  high  tem- 
perature may  be  used  without  reducing  the  fuel  bed  below  the  temperature  of  gasifi- 
cation or  reaction. 

In  order  to  handle  the  gases  at  this  high  temperature  an  air  injector  is  used, 
the  primary  air  being  sent  into  the  injector  at  a  pressure  of  about  25  ounces  of 
mercury  by  a  positive  blower.  This  primary  air  when  mixed  with  the  flue  gas  which 
it  induces,  is  charged  to  the  extent  of  about  9%  COz  on  an  average  running  variously 
from  8  to  12%.  The  fuel  gas  as  a  rule  shows  an  analysis  of  about  17  to  19%  CO2 
when  the  temperature  of  a  bench  is  at  its  working  heat,  approximating  2100°  F.  In 
these  benches  the  depth  of  fuel  bed  runs  from  2^  to  5  ft.,  depending  upon  the 
nature  of  the  fuel  used. 

Retort  Bench  Firing. — A  key  to  the  drawing  herewith  shown,  where  the  principle 
is  applied  to  a  gas-works  retort  bench,  is  as  follows: 

It  will  be  noted  that  the  arch  walls  (A)  are  built  entirely  of  fire-brick;  no  red 
brick  whatever  being  used  in  their  construction.  The  back  wall  (B)  when  two  benches 
are  not  built  back  to  back  is  constructed  of  "  9's  "  of  fire-brick  backed  by  a 
good  quality  of  red  brick  laid  in  lime  mortar  well  tempered  with  Portland  cement. 

The  arches  (C)  are  constructed  on  heavy  forms,  the  least  possible  amount  of 
fire-clay  being  used  in  laying.  The  arch  tile  are  made  of  special  fire-clay  material 
to  withstand  the  high  temperature  to  which  they  are  subjected.  The  arch  (E)  is 
constructed  of  fire-clay  tile  arched  in  form  and  made  hollow  to  reduce  the  weight 
and  also  to  prevent  loss  of  heat  by  radiation.  The  air  space  (D)  between  the  two 
arches  forms  an  additional  insulation  against  radiation  and  also  relieves  the  arch 
(C)  of  any  unnecessary  weight,  thus  avoiding  any  sagging  of  the  arch. 

The  insulation  filling  (F)  of  fine  ash  is  for  the  purpose  of  lessening  the  weight  on 

354 


THE   DOHERTY  COMBUSTION   ECONOMIZER 


355 


I 

a 


£ 

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356  GAS   PRODUCERS 

the  hollow  arch  arid  forms  an  excellent  insulation  on  top  of  the  bench,  covered  as 
it  is  by  two  courses  of  brick  (G)  which  make  the  top  of  the  bench  flat  and  smooth, 
and  readily  kept  clean  in  addition  to  being  cool. 

The  arch  lintel  (H)  is  made  of  cast  iron  heavily  ribbed  and  supported  by  the 
arch  walls,  the  brick-work  above  being  constructed  in  such  a  way  as  to  avoid  twisting 
the  lintel  and  necessitating  periodical  repairs  at  this  point. 

The  flues  (J)  are  carried  up  the  back  wall  and  are  of  large  proportions  lined 
throughout  with  fire-brick  ending  with  a  short  fire-brick  stack,  steel  bound.  This 
stack  may  readily  be  extended  through  the  retort  house  roof  by  a  length  of  steel 
stack  if  desired.  No  stack  clampers  whatever  are  used  on  top  cf  the  bench.  The 
dampers  are  placed  in  a  more  convenient  position  where  there  is  little  likelihood 
of  their  being  moved  through  carelessness. 

All  binding  steel  is  supported  from  the  foundation  direct,  heavy  iron  sole  plates 
being  used  to  insure  a  firm  footing.  This  binding  steel  may  be  either  of  heavy  channel 
iron  or  I-beam  sections,  as  local  conditions  may  warrant.  The  lower  anchor  bolts 
are  tied  in  the  foundation  and  not  in  the  arch  walls.  The  steel  cross  ties  above 
are  supported  by  the  binding.  Whenever  necessary  the  back  walls  and  the  end 
walls  are  reinforced  with  steel  to  prevent  warping  and  bulging. 

The  ash  pan  (1)  extends  flush  with  the  front  of  the  bench. 

The  bearing  bar  supports  (2)  are  firmly  tied  in  the  brickwork  and  permits 
the  steel  bearing  bars  (3)  to  be  removed. 

The  side  plates  (4)  are  supported  and  ribbed  to  avoid  breakage  and  prevent 
the  removal  of  the  step  bars  (5)  which  they  support  and  also  the  steel  and  end  bearing 
bars  (6). 

The  grate  bars  (7)  are  of  bar  steel  supported  on  four  bearing  bars  as  shown.  The 
end  bearing  bars  (6)  are  of  steel  and  easily  removed  if  desired,  but  when  in  place 
support  the  grate  bars  and  keep  them  properly  placed. 

The  ash  door  lintel  (8)  is  a  single  casting  ribbed  and  arched  in  form,  supported 
on  each  side  by  the  brick-work  and  relieved  of  all  unnecessary  weight  by  the  fire- 
arch  (9)  as  shown  in  the  cross-section. 

The  ash  door  frame  (10)  is  bolted  to  both  the  ash  pan  and  the  ash  door  lintel, 
forming  an  additional  means  of  support  for  the  ash  door  lintel.  The  ash  door  (11) 
is  very  large,  permitting  the  ashes  to  be  shaken  down  and  withdrawn,  is  ribbed  to 
prevent  warpage  and  is  finished  on  the  face  to  prevent  leakage.  The  ash  door  is 
equipped  with  a  steel  liner  to  prevent  radiation.  The  whole  door  is  fastened  tight 
by  means  of  a  light  steel  cotter  bar  with  latch  and  cam  tightener. 

The  injector  throat  (12)  is  fire-clay  as  is  also  the  top  lining  (13)  the  whole  being 
inclosed  in  the  cast-iron  injector  housing  (14)  tied  firmly  to  the  ash  lintel  door  by 
means  of  tie  rods  as  shown.  This  injector  housing  is  equipped  with  an  injector 
damper  (15)  as  shown  for  the  admission  of  primary  air  when  required.  The  injector 
nozzle  (16)  is  clamped  fast  to  the  injector  housing  by  means  of  the  small  collar  and 
yoke  shown  and  may  be  removed  when  necessary. 

This  injector  nozzle  is  so  designed  that  while  the  volume  of  air  passing  through 
it  may  be  varied  the  pressure  and  velocity  remain  substantially  the  same.  This 
adjustment  of  the  injector  nozzle  opening  is  by  means  of  a  handwheel  on  top,  which 
is  connected  to  a  non-rising  stem. 


THE   DOHERTY   COMBUSTION    ECONOMIZER  357 

The  bustle-pipe  (17)  which  may  be  either  placed  underground  or  supported  by 
the  charge  floor  beams  in  some  similar  manner  to  that  shown,  carries  air  from  a 
positive  pressure  blower  (not  shown)  installed  at  any  suitable  point  in  the  plant. 
The  laterals  (18)  conduct  the  air  from  the  bustle  pipe  to  the  injector  nozzles,  a  quick 
closing  lever-handle  gate-valve  (19)  being  installed  in  each  lateral  for  the  purpose 
of  cutting  off  the  supply  of  air  to  the  bench  without  changing  the  adjustment  of 
the  injector  nozzle. 

The  secondary  dampers  (20)  and  frames  (21)  are  of  cast  iron,  the  frame  being 
laid  in  the  brick-work,  but  may  be  removed  should  occasion  require.  The  form  of  the 
frame  is  such  that  the  opening  is  elevated  and  protected  by  a  small  hood  above, 
which  gives  protection  from  dirt  and  coke  and  protects  the  damper  with  its  cap-screw 
clamp. 

The  coke  chute  frame  (22)  and  cover  (23)  is  firmly  attached  to  the  front  of  the 
bench. 

All  recuperator  flues  and  other  points  for  cleaning  out  the  bench  are  equipped 
with  cast-iron  peep-hole  frames  (24)  and  covers  (25)  a  number  of  the  latter  being 
supplied  with  swing-sight  covers  (26)  for  the  convenience  of  the  operator.  These 
peep-hole  frames  are  embedded  in  the  front  wall,  and  at  points  of  high  temperature 
are  protected  by  fire-clay  blow-plugs  (27)  as  shown.  The  peep-hole  covers  hang  on 
trunnions  engaging  hooked  lugs  on  the  frame  in  a  similar  manner  to  that  employed 
in  hanging  the  coke  chute  cover. 

The  blow  plugs  (28)  are  cast  iron  with  an  eye  in  each  for  removal  when  the  com- 
bustion chamber  requires  cleaning.  The  fire-clay  blow-plugs  (27)  are  removed  for 
cleaning,  but  the  swinging  sight  covers  in  the  peep-hole  permit  the  operator  to  view 
the  interior  of  the  combustion  chamber  without  the  removal  of  the  entire  blow-plug. 

Referring  to  the  bench  filling  details,  the  producer  or  furnace  (29)  is  built 
entirely  of  large  producer  blocks  of  a  special  quality  of  fire-clay,  insuring  a  tight  and 
durable  producer  having  a  minimum  number  of  joints.  The  producer  arch  is  composed 
of  a  key  and  three  sets  of  fire-clay  blocks  on  each  side,  the  lower  being  the  caps  (30) 
on  top  of  which  rest  the  skewbacks  (31)  supporting  the  springers  (32).  It  will  be 
noticed  that  the  ducts  (33)  pass  through  the  skewbacks  and  springers  and  carry  the 
secondary  air  from  the  recuperator.  The  springers  contain  a  small  secondary  tuyere 
(34)  each  as  indicated.  The  producer  key  (35)  spans  between  the  springers  on  each 
side  and  forms  the  key  of  the  arch.  The  entire  interior  of  this  producer  is  coated 
with  a  flux  mixture  which  when  hot  glazes  the  surface  binding  the  tile  together 
thus  insuring  the  stability  of  the  whole  mass  and  the  tightness  of  all  the  joints. 

The  recuperator  tiles  (36)  are  made  in  convenient  lengths  of  one  piece,  having 
a  circular  bore  and  an  octagonal  exterior.  The  top  recuperator  tile  (37)  are  similar 
in  eveiy  respect  to  the  recuperator  tiles  except  that  they  have  a  hole  (38)  in  the 
side  to  permit  the  products  of  combustion  to  enter  after  they  pass  beneath  the 
lowest  retorts. 

The  stack  dampers  (39)  are  located  in  the  second  row  of  recuperator  tiles  from 
the  bottom  as  shown,  thus  placing  them  out  of  the  way  and  impossible  to  move 
by  accident  although  readily  adjusted  with  a  hook  when  required. 

The  miters  (40)  are  light  but  strong  and  tightly  cover  the  joint  between  adjacent 
sections  of  the  recuperator  tile  form  the  spacers  for  the  passage  carrying  the 


358 


GAS    PRODUCERS 


secondary  air  and  constitute  columns  of  rigid  support  aside  from  the  column  effect 
derived  from  the  recuperator  tiles  themselves. 

The  spacers  (41)  are  the  same  width  as  the  miters  and  also  cover  a  portion  of 
the  recuperator  joints,  and  insure  alignment  in  the  complete  work. 

The  front  returns  (42)  which  connect  one  row  of  recuperator  tile  with  another, 
form  a  part  of  the  front  wall  and  are  fitted  with  the  peep-hole  frames  mentioned. 
These  front  returns  are  not  tied  in  any  way  to  the  recuperator  tile,  thus  permitting 
difference  in  expansion  to  both  recuperator  and  front  returns,  resulting  in  a  continually 
tight  recuperator. 


Recuperators  of  Doherty  Benches. 


Bench    Furnace    in    Process    of    Construction 
Large  blocks  are  used  instead  of  brick. 


FIG.    188. 


The  back  returns  (43)  are  similar  to  the  front  returns  except  that  they  are 
lighter  in  construction  and  are  not  fitted  with  peep-hole  frames. 

They  also  connect  one  row  of  recuperator  tile  with  another,  but  like  the  front 
returns  are  not  tied  in  any  way  to  the  recuperator  tile. 

The  shims  (44)  span  between  the  miters  and  form  a  backing  for  the  blocks  of 
the  producer  and  form  an  additional  protection  against  leakage  between  the 
producer  and  the  secondary  air  passage. 

The  liners  (45)  are  laid  close  against  the  arch  wall  and  form  a  column  of  support 
for  the  setting  above,  thus  relieving  the  recuperator  of  excessive  weight  in  addition 
to  insuring  protection  to  the  arch  wall. 


THE   DOHERTY   COMBUSTION   ECONOMIZER  359 

The  step  miters  (46)  together  with  the  skewbacks  (31),  springers  (32),  and  fillers 
(47)  form  an  elastic  or  slip  joint  thus  relieving  the  recuperator  from  liability  of 
damage  through  a  possible  difference  in  expansion  between  the  recuperator  proper 
and  the  walls  of  the  producer. 

In  this  type  of  construction  recuperator  leakage  is  reduced  to  a  minimum. 

The  front  wall  is  constructed  almost  entirely  of  special  blocks  of  suitable  size. 
The  injector  housing  with  its  fire  clay  lining  is  placed  immediately  above  the  ash 
door  lintel  in  the  center  of  the  bench.  The  dow7n-takes  (48)  and  the  shunt  returns 
(49)  connect  with  the  down-flue  blocks  (50)  leading  to  the  injector  inlet  (51).  This 
injector  inlet  in  turn  opens  into  the  top  lining  (13)  above  the  injector  throat  (12). 

The  coke  chute  bottdm  (52)  rests  above  the  injector  inlet  and  may  be  renewed 
if  necessary,  together  with  the  coke  chute  top  (53)  immediately  above.  These  tiles 
are  subjected  to  wear  and  are  heavy  enough  for  this  purpose,  but  may  be  removed 
and  new  ones  installed  should  the  wear  be  excessive. 

The  fire  arch  (9)  is  massive  and  thoroughly  protects  the  ash  door  lintel  from 
excessive  heat  and  load. 

The  tuyere  blocks  (54)  contain  the  secondary  openings  (55)  which  open  into  the 
combustion  chamber  (56),  support  the  lower  retorts  (57),  and  form  a  secondary 
cleaning  and  equalizing  duct  (58).  This  equalizing  duct  is  accessible  through  one 
of  the  peep-hole  frames  shown  in  the  front  of  the  bench.  The  tuyere  blocks  also  form 
a  support  for  the  lower  central  setting  blocks  and  have  a  lip  which  prevents  the 
clogging  of  the  tuyeres  from  a  collection  of  slag. 

The  retorts  (57),  (59),  and  (60)  are  made  of  fire-clay  material  thoroughly  tamped 
and  hard  burned,  great  care  being  taken  that  they  are  of  uniform  size  and  shape  and 
of  uniform  quality  throughout. 

The  setting  tile  are  light,  but  their  combined  supporting  area  is  in  excess  of  that 
usually  used,  which  results  not  only  in  better  support  for  the  retorts,  but  adds  to  the 
effective  radiating  surface,  insuring  a  more  uniform  distribution  of  heat  with  less 
likelihood  of  damage  resulting  from  quick  changes  of  temperature. 

The  patent  retort  collars  (61)  are  cast  in  two  sections  and  clamped  firmly  around 
the  mouth  of  the  retort  with  a  packing  between  of  rust  joint  material.  On  page  26 
are  two  views  of  these  retort  collars  attached  to  a  retort  W7hich  is  ready  to  be 
installed.  The  flange  on  the  face  of  the  collar  is  tapped  to  suit  the  mouthpiece  to 
be  used  and  which  is  fastened  to  the  collar  by  means  of  studs.  It  will  be  readily 
seen  that  this  method  of  attaching  a  mouthpiece  to  a  fire-clay  retort  is  far  superior 
to  the  antiquated  method  of  using  bolts  exending  into  the  retort  itself.  These  bolts 
burn  off  and  give  trouble  by  allowing  the  mouthpiece  to  sag  and  pull  away  from  the 
face  of  the  retort.  The  use  of  this  retort  collar  permits  a  retort  of  uniform  cross- 
section  throughout  and  also  allows  removing  and  replacing  a  mouthpiece  at  will 
without  damage. 

The  bent  pipes  (63)  and  stand-pipes  (64)  are  of  cast  iron,  the  latter  being 
furnished  of  steel  if  desired. 

The  bridge  pipes  (65)  are  of  standard  design  as  are  also  the  dip  pipes  (66) 
and  the  hydraulic  main  (67). 

The  hydraulic  main  is  supported  on  adjustable  chairs  (68)  resting  on  I-beam& 
(69)  spanning  between  the  cross-ties  (70)  supported  by  the  binding. 


360  GAS   PRODUCERS 

The  gas  rising  from  the  fuel  bed  of  the  producer  (29)  passes  between  the  keys 
(35)  as  indicated  by  the  arrows  into  the  combustion  chamber  (56).  In  this  chamber 
the  gas  passes  between  the  setting  and  around  the  retorts,  down  to  the  open  spaces 
(71)  immediately  beneath  the  bottom  retorts;  thence  through  the  openings  (38)  in 
the  top  recuperator  tile  into  the  recuperator  proper.  Then  forward  to  the  shunt 
return  (49)  where  a  portion  enters  the  next  lower  row  of  recuperator  tile  and  a  portion 
is  drawn  into  the  down-flue  blocks  (50). 

That  portion  of  the  gas  which  enters  the  second  row  of  recuperator  tile  passes 
to  the  back  returns  and  then  down  and  forward  again  to  the  next  front  return  and 
so  on  until  it  finally  enters  the  stack  (1)  and  then  to  waste. 

The  secondary  air  enters  through  the  damper  frames  (21),  passes  back  through 
the  ducts  (72)  and  rises  between  the  rows  of  miters  and  spacers  and  completely 
surrounds  the  recuperator  flues  until  it  enters  the  ducts  (33)  leading  to  the  equalizing 
duct  (58).  A  portion  of  this  secondary  air  is  short-circuited  through  the  small 
secondaries  (34)  below  the  keys  (35) ;  the  remainder  entering  the  combustion  chamber 
(56)  through  the  tuyeres  (55)  leading  from  the  equalizing  duct. 

The  primary  air  under  pressure,  and  issuing  from  the  injector  nozzle,  enters  the 
throat  of  the  injector,  producing  a  partial  vacuum  or  inductive  effect  in  the  space 
immediately  above  the  throat,  which  effect  results  in  a  certain  percentage  of  the  gases 
entering  the  space  beneath  the  lowest  retort,  being  drawn  into  the  shunt  return, 
then  through  the  down-take  blocks,  into  the  down-flue  blocks  to  the  injector  inlet. 
The  gases  thus  induced  into  the  injector  top  are  forced  by  the  air  issuing  from  the 
injector  nozzle  through  the  throat  and  injected  into  the  ash  pan  beneath  the  grate 
bars  of  the  producer. 

At  the  same  time  these  gases  are  thoroughly  mixed  with  the  primary  or  injector 
air  issuing  from  the  injector  nozzle  before  they  pass  up  through  the  fuel  bed. 

Chemical  Reactions. — As  the  hot  coke  is  usually  used  for  fuel  in  a  gas-bench 
producer,  we  will  consider  coke  as  the  fuel  used  in  this  case.  The  depth  of  the  fuel 
bed  should  be  4  or  5  ft.,  leveled  off  on  top.  The  stack  dampers  should  be  so 
adjusted  that  the  pressure  in  the  producer  is  as  near  atmospheric  pressure  as  possible, 
so  that  there  will  be  neither  a  tendency  for  the  producer  gas  to  blow  out  when  the 
coke  chute  cover  is  removed  nor  a  tendency  for  the  air  to  draw  in.  The  secondaries 
should  be  so  adjusted  that  an  analysis  of  a  sample  of  the  products  of  combustion 
taken  well  back  in  the  duct  immediately  below  the  lowest  retort  will  show  on  an 
average  from  18  to  19%  C02  and  1  or  2%  O.  The  injector  nozzle  opening  and  air 
pressure  should  be  so  adjusted  that  an  analysis  of  a  sample  of  the  primary  mixture 
taken  well  back  in  the  space  beneath  the  grate  bars  of  the  producer  will  show  an  average 
of  from  8  to  12%  CO2  and  8  to  12%  O. 

The  producer  gas  or  CO  rising  from  the  fuel  of  the  producer  and  at  a  temperature 
above  that  required  for  ignition  comes  in  contact  with  the  highly  pre-heated 
secondary  air  issuing  from  the  tuyeres  below  the  keys  where  a  partial  combustion 
takes  place.  This  partial  combustion  is  for  the  purpose  of  preventing  any  possible 
collection  of  carbon  on  the  producer  keys,  thus  decreasing  the  opening  between  the 
producer  and  the  combustion  chamber  which  sometimes  occurs  when  coal  is  used  and 
the  producer  gas  formed  is  very  rich.  The  gas,  after  passing  the  small  secondary 
tuyeres  and  between  the  keys  of  the  producer  arch,  comes  in  contact  with  the  balance 


THE    DOHERTY  COMBUSTION   ECONOMIZER  361 

of  the  secondary  air  issuing  from  the  large  tuyeres  above  into  the  combustion  chamber. 
At  this  point  complete  combustion  starts.  The  highly  heated  products  of  combustion 
in  their  passage  around  the  retort  and  before  entering  the  recuperator  give  up  a  cer- 
tain portion  of  their  heat  to  the  retorts  and  settings.  Entering  the  spaces  immediately 
below  the  lowest  retorts,  the  products  of  combustion  are  divided,  one  portion  going 
to  the  injector  and  thence  beneath  the  grate  bars,  and  the  other  portion  entering  the 
recuperator,  where  by  contact  with  the  enormous  area  exposed  it  again  parts  with  a 
large  portion  of  the  heat  it  still  retains,  which  heat  is  transmitted  through  the  thin 
walls  of  the  recuperator  tile  to  be  rapidly  absorbed  by  the  secondary  air  in  direct 
contact.  This  secondary  air  rises  by  its  own  increase  in  temperature  and  volume  and 
finally  enters  the  combustion  chamber  through  the  tuyeres  at  substantially  the  same 
temperature  as  the  products  of  combustion  when  they  enter  the  recuperator. 

Advantages. — The  advocates  and  manufacturers  of  the  Doherty  bench  claim  its 
advantage  over  furnaces  using  H20  or  steam  as  an  endothermic  agent,  through 
the^fact  that  clinker  is  prevented  and  the  fire  is  not  "  quenched/'  as  in  the  case  of 
the  agents  aforesaid. 

If  any  such  advantage  or  superiority  exists,  in  the  opinion  of  the  writer,  it  depends 
upon  the  following  reasons: 

1.  The  high  temperature  of  the  flue  gases  permits  a  large  volume  to  be  used  and 
converted  in  the  fire  bed  into  potential  gas,  as  previously  explained. 

2.  That  this  large  volume  obtained  with  low  density  more  thoroughly  dissemi- 
nates through  the  entire  volume  of  fuel,  and  its  action  is  therefore  more  general,  or 
in  other  words,  it  does  not  channel  or  concentrate  its  action  as  does  the  heavier 
aqueous  vapor  or  steam,  with  a  consequent  formation  of  "  dead  spots  "  adjacent  to 
such  channels.      This  is  plausible,  by  reason  of   the  difference   in  density  between 
the  hot  gases  and  the    heavier   and    more   penetrating   steam  which  seeks   lines  of 
cleavage  rather  than  diffusion  and  which  is  much  more  concentrated  in  its  action. 

To  this  fact  we  would  attribute  the  non-production  of  clinker  in  the  process,  that 
is  to  siay,  it  is  possible  with  either  C02  or  H20  to  maintain  the  fire  bed  at  the  tem- 
perature below  the  critical  point  of  fluxing  fusible  ash,  but  while  this  may  be  done 
with  the  use  of  the  hot  flue  gases  and  at  the  same  time  a  reasonable  reaction  of  such 
gases  to  CO  be  obtained,  yet  if  a  sufficient  amount  of  H2O  be  used  to  maintain 
sufficiently  low  the  temperature  of  the  fire,  it  would  be  so  pitted  with  "  dead  spots  " 
due  to  its  channeling  as  to  produce  an  excessive  amount  of  C02  in  the  resultant  gas, 
or,  in  producer  parlance,  the  fire  would  be  "  killed." 

It  is  also  a  question  whether  the  temperature  requisite  for  the  complete  dissocia- 
tion of  steam  and  its  reaction  from  H20+C  to  2H+CO  does  not  require  a  higher  tem- 
perature than  the  critical  point  of  clinker  formation  as  aforesaid,  while  it  is  possible 
that  the  reaction  C02+C  to  2CO  can  occui  at  a  relatively  lower  temperature,  that 
is  to  say,  below  the  clinker  point,  or  perhaps  over  a  wider  range  of  temperature. 

This  fact,  of  course,  depends  upon  the  nature  of  the  fuel  used,  conditions  of 
radiation,  and  flame  temperature,  but  it  is  just  possible  that  they  form  important 
elements  in  the  equation. 

3.  It  is  a  chemical  fact  that  the  reaction  of  C02  to  CO  is  constant  or  what  is  known 
as  a  positive  reaction,  while  the  combination  of  H2O  and  C  are  variable. 

4.  It  is  claimed  with  some  justice  that  while  the  supply  of  steam  is  obtained  at 


362  GAS   PRODUCERS 

some  expense  of  fuel,  labor,  and  fixed  charges,  the  use  of  flue  gas  creates  the  utilization 
of  an  otherwise  useless  product.  Again,  the  gas  obtained  from  the  system  described, 
is  more  uniform  or  constant  in  its  value  than  that  made  with  H20.  As  opposed  to 
these  arguments  is  the  fact  that  the  H20  gas  is  of  higher  calorific  value. 

The  chief  contentions  made  by  the  respective  advocates  of  the  C02  and  H2O 
theories  are:  with  the  temperature  of  the  several  conversions;  with  the  respective 
specific  heats  of  the  two  products,  and  their  constant  abstraction  of  sensible  heat  from 
the  fire  at  the  expense  of  fuel. 

The  advocates  of  the  H2O  theory  point  particularly  to  the  high  specific  heat 
of  water  vapor  as  compared  to  C02  per  unit  of  weight,  but  as  a  matter  of  fact  upon 
a  basis  of  molecular  equivalents,  they  are  about  the  same,  C02  being  slightly  the 
higher,  and  it  is  doubtful  whether  under  practical  conditions  there  is  much  difference 
between  the  two,  when  the  C09  plus  its  attendant  nitrogen  is  compared  with  the  H20. 

The  burden  of  chemical  advantage  appears  to  be  against  the  C02  theory,  while 
in  its  favor  are  notable  results  in  e very-day  practice. 

As  herein  suggested  from  both  observation  and  practice  the  writer  believes  that 
the  conditions  of  a  physical  nature  involved  in  the  question  are  more  prominent  than 
those  of  a  chemical  nature,  and  that  the  physical  elements  are  more  prominent  and 
practical  than  the  chemical  considerations  involved. 

There  is  a  likelihood  that  in  the  use  of  CO2  in  producer  regulation,  there  is  a 
certain  prevention  of  clinker  by  a  "  generalization  "  of  combustion  (as  opposed  to 
concentration  or  localization  of  combustion)  due  to  the  dilution  of  the  air  admitted 
and  the  neutral  action  of  said  CO2,  in  addition  to  its  heat  absorbing  properties. 

If  flame  temperature  is  a  function  of  the  activity  of  combination  of  the  elements 
per  unit  of  space  (other  conditions  being  equal)  then  the  converse  must  hold  and 
flame  temperature  be  lower,  and  combination  be  less  localized,  where  one  or  both 
elements  are  diluted,  and  combustion  diffused. 

An  analogy  of  this  is  indicated  by  the  performance  of  lignites  and  other  low 
grade  coals  containing  high  amounts  of  neutral  or  non-combustible  matter,  which 
fuels  in  producer  gasification  maintain  so  low  a  flame  temperature  as  to  require  but 
little,  and,  in  extreme  cases,  no  endothermic  agent  for  controlling  or  absorbing  the 
"  plus  "  heat  generated  within  the  producer. 

Operation  Details. — The  following  data  shows  some  of  the  conditions  found 
by  the  writer  in  a  plant  of  the  type  herein  described: 

Depth  of  fuel  bed,  4  to  5  ft. 

Nature  of  fuel  in  producer,  hot  coke  withdrawn  from  the  retorts.  The  coal  is 
known  as  "  Berwin  mine  run,"  bituminous,  mined  in  Southwestern  Colorado. 

Weight  of  charge  in  retorts,  333  Ibs.  in  small  benches,  400  Ibs.  in  large  benches. 

Length  of  time  for  carbonizing,  4  hours. 

Percentage  of  coke  drawn;  about  67%  of  the  coal  remains  as  coke. 

Bench  fuel  per  ton  of  coal  carbonized,  on  small  benches,  270;  on  larger  benches 
250  Ibs. 

Temperature  of  flue  gases,  outlet  of  recuperator,  about  600°. 

Temperature  of  primary  air,  flue  gas  mixture  under  grate  bars,  or  outlet  of 
inductor,  varies  from  a  minimum  of  200  to  800°  (as  when  a  retort  cracks  and  allows 
coal  gas  to  escape  into  retort  oven.) 


THE   DOHERTY  COMBUSTION   ECONOMIZER  363 

As  a  matter  of  course  the  operation  of  apparatus,  such  as  is  herein  described, 
must  depend  upon  the  fuel  used  in  the  producer,  the  coal  carbonized,  the  size  of 
charges,  the  length  of  carbonization  and  kindred  elments.  However,  it  will  also  be 
found  that  each  bench  and  producer  has  its  individual  characteristics,  largely  due 
to  conditions  of  radiation,  ventilation,  and  environment,  which  must  be  separately 
and  severally  learned  to  facilitate  and  minimize  the  individual  equation  in  operation. 
However,  the  writer  advises  a  thorough  system  of  draft  gauges  which  will  indicate  at 
a  glance  the  draft  suction  of  the  stack,  pressure  of  the  air  through  the  blower  upon  each 
bench,  and  the  suction  created  by  the  primary  air  upon  the  syphon  of  the  injector. 

It  may  also  be  of  advantage  to  install  these  gauges  at  other  points  which  will 
reflect  conditions  of  stoppage,  of  back  pressure,  which  is  often  due  to  soot,  lampblack, 
dust,  or  ashes. 

The  eye  of  the  operator  readily  learns  the  heat  of  the  producer,  which  is  most 
advantageous  to  best  results,  but  the  minimizing  again  of  errors  may  be  done  by 
recording  pyrometers  to  much  advantage. 

As  in  all  other  classes  of  producers  it  has  been  found,  in  the  experience  of  the 
writer,  that  a  dull  orange  is  the  most  efficient  heat  color  to  be  maintained,  that  is  to 
say,  the  heat  should  be  maintained  below  the  appearance  of  any  white  lights,  which 
are  invariably  the  sign  of  a  fusing  or  clinkering  heat.  The  appearance  of  white,  either 
as  reflected  lights  or  intermingled  with  the  orange  shades,  are  the  danger  signal  alike 
in  producer  gas  or  water  gas  operation. 


CHAPTER   XVII 
COMBUSTION   IN   FURNACES 

COMBUSTION 

IT  is  not  the  desire  of  the  author  to  attempt  an  essay  upon  the  subject  of  com- 
bustion, in  the  discussion  of  which  we  have  no  empiric  premises,  the  foundations  and 
data  which  are  extant  being  greatly  at  variance,  and  without  factors  explanatory 
of  its  various  forms  and  phases. 

It  is  altogether  possible  that  the  author  is  working  from  a  wrong  direction  in  the 
principles  that  he  here  lays  down,  but  for  the  benefit  of  those  who  may  desire  to 
prosecute  the  subject  to  a  more  finished  degree,  he  proposes  the  following  hypotheses, 
which  have  been  of  service  to  him  in  the  solution  of  a  number  of  practical  problems 
and  which  may  serve  as  a  working  basis  for  more  active  and  complete  analyses. 

Heat 'and  Temperature. — To  begin  with,  it  is  necessary  to  differentiate  between 
heat  and  temperature,  terms  which  have  unfortunately  been  often  interchangeably 
used.  The  distinction  between  these  two  is  identical  with  those  terms  used  in 
electricity,  as  amperage  and  voltage,  volume  and  pressure,  in  which  heat  corresponds 
to  the  former  and  temperature  to  the  latter. 

Assuming  these  divisions,  we  will  proceed  to  draw  certain  other  analogies,  between 
the  action  of  heat  and  temperature,  and  the  known  phenomena  of  light.  In  this 
connection  we  find  the  law  of  light  wherein  the  intensity  of  light  increases  inversely 
as  a  square  of  the  distance  from  its  point  of  emanation.  In  the  corollary  with 
temperature,  this  depends  upon  three  things,  namely,  the  amount  of  heat  given  off, 
the  time  in  which  it  is  given  off,  and  the  area  within  which  it  is  given  off. 

Taking  these  factors  into  consideration,  we  find  from  a  practical  standpoint,  that 
flame  temperature  depends  upon  the  amount  of  heat  envolved  in  combustion  within 
a  unit  of  area  within  a  unit  of  time,  and  we  may  say  that  this  temperature  has  (by 
reason  of  conduction,  radiation,  etc.)  an  evolved  heat  which  increases  inversely  as 
the  square  of  the  unit  within  which  the  combustion  takes  place. 

We  also  find  that,  assuming  the  unit  to  remain  constant,  the  temperature 
increases  directly  with  the  heat  liberated  by  combustion,  and  inversely  as  the  square 
of  the  radiation. 

The  above  hypothesis  accounts  for  the  phenomena  resultant  upon  high  pressure 
and  delivery  of  gas  and  air  in  all  the  ramifications  of  Bunsen  burner  work. 

We  are  well  acquainted  with  the  analogy  of  the  search-light  whose  lenses  merely 
tend  to  parallel  the  rays  of  light  and  prevent  diffusion  common  to  all  forms  of  radiant 

364 


COMBUSTION   IN   FURNACES  365 

energy.  This  is  also  shown  in  both  air  and  water  jets,  acting  under  pressure,  wn'ich 
tend  to  diffuse  in  a  ratio  about  inversely  as  a  square  root  of  the  initial  pressure. 

Wi>  find  therefore  that  under  conditions  of  pressure  this  diffusion  is  retarded  and 
the  cross-section  or  unit  space  tends  to  be  more  constant  or  protracted,  there  being 
a  diminution  of  radiation.  In  other  words,  where  conditions  of  high  pressure 
deliver}'  maintain,  there  is  a  resultant  cohesion  or  condensing,  due  to  the  initial 
pressure,  which  tends  to  retain  the  combustion  within  a  more  confined  flame  area 
subtending  a  decrease  of  radiation. 

Velocity  of  Flame  Propagation. — Again,  another  feature  with  which  we  are  not 
exactly  acquainted,  comes  with  the  fact  that  the  compression  of  the  gas  brings  its 
molecules  or  atoms  into  closer  juxtaposition,  and  the  transmission  of  heat  evolved 
is  more  rapid  and  complete.  This  is  shown  by  actual  test's,  which  go  to  prove  that 
under  conditions  of  high  pressure  delivery,  the  same  amount  of  heat  is  evolved  with 
less  fuel,  or  greater  heat  with  an  equal  fuel  under  combustion.  We  might  term  this, 
through  lack  of  a  better  word,  "  heat  propagation,"  as  the  action  is  analogous  to 
that  of  flame  propagation,  which  latter  is  undoubtedly  a  factor  in  the  radiation 
activity  herein  described. 

Another  manifestation  of  this  heat  propagation,  or  more  strictly  speaking,  propa- 
gation of  temperature,  is  seen  in  the  cylinder  of  the  gas  engine  under  high  compression. 
This  is  possibly  the  best  illustration  that  we  have  of  the  conditions  of  combustion 
due  to  a  compressed  gas,  although,  in  addition  to  the  "  radio-activity  "  which  we 
have  just  mentioned,  there  is  in  this  condition  the  added  value  of  the  fuel,  due  to  the 
compression  of  a  much  larger  amount  of  combustible  within  a  given  space,  in  fact 
doubling  the  amount  of  this  combustible  at  the  pressure  of  each  additional  atmosphere. 

In  conditions  of  daily  practice,  we  will  therefore  see,  that  up  to  a  certain  point 
we  may  increase  the  flame  temperature  by  increasing  the  initial  pressure.  This  is 
caused  by  the  fact,  as  before  mentioned,  that  within  certain  limits  the  compression 
or  contraction  of  the  flame,  due  to  initial  pressure,  in  increased  or  maintained 
(within  certain  limits)  at  a  greater  ratio  than  the  diffusion  and  consequent  radiation, 
or,  as  it  is  commonly  termed,  "  ventilation." 

Beyond  that  point,  however,  the  velocity  of  combustion  subtends  an  increased 
velocity  of  radiation  or  ventilation,  which  detracts  from  the  gross  results  of  the 
temperature  accrued.  Thus  we  have  the  phenomena  known  as  "  blowing-cold," 
that  is  to  say,  the  velocity  or  initial  pressure  of  the  products  of  combustion  is  so 
great  as  to  pass  under  the  flame  area  when  only  partially  consumed.  Here  we  come 
upon  the  time  factor  of  the  equation,  which  under  conditions  of  "  over- ventilation  " 
must  be  taken  into  consideration. 

Theoretically  combustion  of  all  sorts  has  always  been  expressed  by  T\  —  T2,  that 
is  to  say,  the  highest  initial  temperature  and  the  lowest  terminal  temperature,  and 
where  the  velocity  becomes  excessive  or  out  of  keeping  with  the  other  conditions  or 
factors  of  the  equation,  the  final  temperature  is  either  unnecessarily  high  or  else  the 
velocity  has  been  too  great  to  permit  of  thorough  chemical  union  upon  the  part  of 
the  ingredients.  Either  of  these  are  generally  summarized  as  "  over- ventilation." 

Recuperation. — Heat  may  be  either  radiant  or  conducted.  The  dominant  law 
of  heat  is  the  law  or  equilibrum  or  the  flow  from  greater  to  less  until  both  terminals 
become  equalized.  This  phenomena  of  equalization  of  temperature  also  requires  a 


366  GAS   PRODUCERS 

time  factor,  and  upon  this  time  factor  and  the  specific  heat  (better  known  as  the 
coefficient  of  heat,  inasmuch  as  it  varies  at  different  temperatures  and  under  different 
conditions  of  various  materials)  all  processes  involving  mufflers,  recuperators  or 
regenerators,  depend. 

Here  again  must  occur  a  balance  between  an  initial  velocity,  which  will  apply 
to  the  absorbing  material  and  the  maximum  amount  of  heat,  and  the  time  and  space 
units  of  contact  necessary  for  the  absorption  of  this  heat  in  working  out  this  equation 
in  exactness,  lies  the  fundamental  principle  of  all  regenerative  processes. 

Where  it  is  possible  to  recuperate  heat,  it  should  invariably  be  done  either  in 
connection  with  the  air  blast  to  the  producers  or  the  cool  air  used  in  combustion. 
The  resultant  economy  is  very  great,  and  under  ordinary  industrial  conditions,  is 
easily  affected,  the  pre-heating  being  carried  up  to  a  point  of  500  or  600°  F.  in  "  con- 
tinuous regenerators."  These  are  usually  sections  of  iron  pipe  with  return  bends, 
but  at  higher  heat,  say  900  or  1000°  F.,  brick-lined  conduits  are  preferable.  Terra- 
cotta pipes  are  sometimes  used,  but  have  a  tendency  to  crack  and  break. 

Great  care  should  be  taken  to  ascertain  that  the  recuperated  heat  does  not  come 
from  any  active  portion  of  the  furnace,  but  only  the  waste  heat,  such  as  the  sensible 
heat  in  the  products  of  combustion,  the  exothermic  heat,  resultant  from  the  material 
to  the  furnace,  etc.  Otherwise  where  sensible  heat  is  abstracted  from  any  active 
portion  of  the  operation,  it  is  doubtful  whether  there  is  any  economy  to  be  obtained. 

Temperature. — The     theoretical   temperature   attainable   by   the    combustion    of 

T)  rp  TT 

any  fuel  may  be  crystallized  in  the  formula  T  =    '    '    '  in  which  B.T.U.  equals  the 

number  of  B.T.U.  generated  by  the  combustion.  W  equals  a  weight  of  gaseous 
products  and  S  equals  the  coefficient  of  heat  absorption  of  the  gaseous  products, 
generally  known  as  "  specific  heat."  This  equation  forms  a  concept  of  the  proposi- 
tions already  laid  down,  that  is  to  say,  the  temperature  is  dependent  upon  the 
conservation  of  the  heat  evolved  within  a  given  area,  and  not  alone  upon  the  rapidity 
of  combustion,  although  this  may  be  contributory,  and  the  exponent  of  the  resultant 
heat  evolved. 

No  better  instance  can  be  shown  than  that  already  alluded  to,  of  the  gas  engine, 
where  the  flame  temperature  obtained  is  undoubtedly  identical  in  the  case  of  city 
gas  of  700  B.T.U.  value  and  producer  gas  of  100  B.T.U.  value. 

The  unit  space  within  which  this  combustion  occurs,  from  a  standpoint  of  the 
net  fuel,  is  very  nearly  the  same,  while,  weight  for  weight,  the  rapidity  of  combustion 
is  of  course  many  times  greater. 

Where  combustion  is  slow,  radiation  under  practical  conditions  is  in  much 
greater  ratio,  and  the  temperature  may  thus  be  indirectly  affected  to  a  considerable 
degree  by  the  rate  of  combustion;  hence  in  practical  operations,  the  more  rapid  the 
rate  of  combustion,  the  higher  the  temperature  usually  produced,  and  the  more  heat 
evolved. 

For  instance  (Ingalls,  " Metallurgy, "  page  264),  "  In  the  operation  of  a  producer 
the  object  is  merely  to  burn  carbon  to  carbon  monoxide,  in  which  latter  the  total 
weight  of  the  products  of  combustion  is  only  6.79  Ibs."  The  average  specific  heat 
of  products  of  combustion  are  given  in  tables,  and  by  substituting  them  for  the 
terms  in  the  formula  the  temperature  "  T  "  is  determined,  which  is  practically  2240 


COMBUSTION    IN   FURNACES 


367 


F.  In  the  diagram  of  flame  temperatures  curve  A  shows  theoretical  temperatures 
which  may  be  obtained  under  assumed  conditions.  Practically,  however,  there  are 
a  number  of  other  features  which  must  be  taken  into  consideration,  two  of  which  are 
the  furnace  walls,  which  must  be  maintained  at  a  temperature  considerably  above 
atmospheric,  with  a  consequent  loss  of  heat  from  radiation  and  conduction,  and  the 
other  being  the  sensible  heat  withdrawn  by  the  ash. 

Assuming  fuel  with  an  ash  content  of  say  10%,  the  ash  loss,  together  with  the 
radiation,  may  be  placed  at  5.7%  of  the  total  heat  generated,  which  figure  approxi- 
mates that  of  practical  tests  (see  Butterfield,  page  87).  The  combination  of  these 
losses  reduced  to  theoretical  in  curve  A  and  more  nearly  obtain  the  curve  B  of 
Chart  1,  which  approximates  the  result  of  practice  as  aforesaid,  always  assuming 


6000 
A 

B 


5000 

E 


4000 
F 


3000 


2000 


1300 


10 


Ca-b.  Wateil  Gas 


FLAME  TEMPERATURES 


Blue  Water  Gas 


Natural  Gas 


Crurfe  Oil  Ga 


Coa.l  Gas 


Produce 


30 


40  50  60 

Per  Cent  Excess  Air 


70 


80 


90 


B 
DC 


100 


FIG.  189. — Flame  Temperatures  as  influenced  by  excess  Air. 


however,  that  the  carbon  is  burned  to  CO  only,  a  condition  which  would  be  impossible 
in  commercial  operation. 

In  recapitulation,  we  find  that  flame  temperature  is  increased  by  (a)  the  intimacy 
of  the  mixture;  (6)  the  compactness  or  density  of  the  fuel  in  delivery;  (c)  the 
amount  of  fuel  delivered  within  a  unit  space;  (d)  the  limitation  of  the  flame  area, 
while  conversely  flame  temperature  is  reduced  by  (a)  increased  radiation,  as  in  the 
case  of  an  increased  flame  area;  (6)  over- ventilation,  as  in  the  case  of  high  velocity 
or  an  excess  of  air. 

This  latter  condition  is  of  course  impossible  to  avoid  in  all  practical  conditions, 
but  it  must  be  maintained  at  the  minimum.  A  table  is  herewith  appended,  showing 
the  loss  of  flame  temperature  due  to  the  excess  of  air.  In  order  to  support  combustion, 
it  is  necessary  in  all  practical  operations,  as  a  matter  of  practice,  to  admit  consider- 
ably more  air  than  is  theoretically  necessary,  in  order  to  secure  proper  combustion, 
the  single  exception  being,  in  the  case  of  firing  powdered  fuel,  where  the  intimacy 


368 


GAS   PRODUCERS 


of  the  mixture  is  such  that  it  practically  attains  approximately  theoretical  conditions, 
or  about  150  cu.ft.  of  air  per  pound  of  powdered  coal  fired. 

FLAME   TEMPERATURES  AND   EXCESS   AIR 


Name  of  Gas. 

Analysis  (Assumed). 

CO2 

111. 

CeHe 

O 

CO 

H 

CH4 

N 

B.T.U. 

Sp.  Gr. 

Carbureted  water  gas  .... 
Coal  gas  

% 
4.5 
2.0 

% 
13.0 
5.5 

% 

% 
0.5 
0.5 
0.4 

% 
29 
11.5 
6.1 
43.5 
20 
1 

% 
32 
43.5 
52.4 
48 
12 

% 
16 
35 
29.3 
.5 
4 
88.5 

% 
5 
2 
4.3 
4 
58 
5.5 

per  cu.ft. 
650 
600 
600 
300 
150 
900 

Air  =1.0 
.60 
.45 
1.40 
.42 
.85 
.55 

Crude  oil  gas  

1.7 
4.0 

4.2 

1.6 

Blue  water  gas  

Producer  gas  

6.0 

Natural  gas  

2 

3 

Name  of  Gas. 

Flame  Temperatures  with  Air  Excess  as  Specified,  Temp,  in  °  F. 

Theoretic. 

10% 

25% 

50% 

100% 

Vols.  Air  to 
Burn  1  Vol. 
Gas,  Theoret. 

Carbureted  water  gas  .... 
Coal  gas  

0 

5909 
4615 
5084 
5291 
3750 
5202 

0 

5422 
4285 
4688 
4918 
3571 
4737 

o 

4887 
3846 
4166 
4477 
3333 
4166 

0 

4166 
3296 
3550 
3846 
3000 
3488 

o 

3217 
2581 
2727 
3030 
2420 
2624 

4.85 
5.47 
5.39 
2.24 
1.15 
8.95 

Crude  oil  

Blue  water  gas  

Producer  gas  

Natural  gas  

The  question  of  the  intimacy  of  the  mixture  has  not  perhape  been  discussed  at 
sufficient  length.  This  may  be  obtained  in  the  highest  degree  of  perfection,  first, 
mechanically,  by  means  of  proper  mixing  chambers,  which  tend  to  break  up  the  air 
and  gas  rivers,  and  interpolate  them,  inter-mixing  them  as  closely  as  possible,  and 
secondly,  thermal  conditions,  under  which  head  it  will  be  found  that  gases  mixed 
with  each  other  and  with  air,  are  best  at  a  high  degree  of  temperature,  due  to  a 
lessened  vapor  tension,  the  proposition  being  very  nearly  analogous  to  that  of  metals 
which  will  only  commingle  in  a  molten  condition. 

This  condition  upon  the  part  of  air  might  almost  be  termed  one  of  fusion,  since 
their  mixture  is  so  much  more  complete  at  the  higher  temperatures,  and  were  there 
no  advantage  to  be  obtained  from  the  restoration  to  the  fire  of  sensible  heat  in 
processes  of  regeneration  and  recuperation,  the  process  would  be  justified  in  itself 
by  the  advantage  accruing  through  the  intimacy  of  the  mixture  obtained. 

Practically  all  burners  now  used  for  either  natural  or  artificial  gas  recognize  the 
necessity  for  thorough  mechanical  mixers,  and  these  mixers  are  arranged  with  either 
rotary  deflectors,  baffles,  etc.  (of  which  the  Kirkwood  is  a  good  example)  for  the 
mechanical  agitation  and  commingling  of  the  air  and  gas  or  gases. 

As  a  matter  of  fact,  at  the  present  stage  of  the  art,  approximation  of  theoretical 
temperatures  (and  here  we  might  again  smphasize  the  fact  that  "  temperature"  is 
the  potential  and  "heat"  the  volume),  is  not  even  close  of  attainment,  which 


COMBUSTION    IX  FURNACES 


369 


subject  we  discussed  at  greater  length  under  the  head  of  "  Furnaces  ";  but  suffice 
it  here  to  say,  that  a  large  portion  of  the  heat  necessary  to  high  temperature  opera- 
tion must  be  recovered  in  the  sensible  form  and  replaced  in  the  fire  through  means 
of  recuperators  or  regenerators. 

Up  to  a  certain  point  a  lack  of  recuperation  may  be  overcome  by  increased 
pressure,  depending  somewhat  upon  the  design  of  the  furnace,  but  when  the  differ- 


15' 5          17.5          19i  5          21.5          2?.  5          2fi'.6 
POUNDS  OF  DRY  COAL  BURNED  PER  SQUARE  FOOT  OF  GRATE  PER  HOUR 


FIG.  190. — Relation  of  Pounds  of  Dry  Coal  Burned  per  Hour  per  sq.ft.  of  Grate  Surface  to  Resulting 

Combustion  Temperature. 


2700 

4C 

) 

li.. 

SJ     2500 

11 

-H 

COMBUSTION-CHAMBER  TEMPERAT 
111 

^ 

s^ 

18 

IB 

20 

S 

11 

/ 

/ 

/ 

18 

/ 

27 

1B 

/ 

ii 

t,t 

/ 

f 

/ 

/ 

/ 

/ 

^2 

/ 

*i~ 

c 

/ 

2 

' 

17.5                   18.5                  21.5                  23.«                25.5                  27.3                  29.5                 31.5                 33.6 

100.000'S  OF  B.T.U.  SUPPOSEDLY     EVOLVED  PER  SQUARE  FOOT  OF  ORATE  PER  HOUR 

FIG.   191. — Relation  of  10,000  B.T.LVs  evolved  per  sq.ft.  of    Grate   Surface  per  Hour  to  Resulting 

Temperature. 

entiation  in  pressure  between  initial  and  terminal  pressures  of  the  furnace  become 
so  great  as  to  subtend  extraordinary  velocity  or  ventilation,  the  efficiency  falls  off 
with  great  rapidity,  and  the  results  are  not  commensurate.  For  this  type  of  work 
1200  to  1500°  F.  with  anthracite,  1600°  with  bituminous  producer  gas,  is  perhaps  the 
limit. 


370  GAS   PRODUCERS 

The  principle  cause  of  this  falling  off  in  efficiency  is  the  fact  that  under  pressure 
both  gas  and  air  tend  to  become  more  dense,  and  with  an  increase  of  vapor-tension, 
their  intimacy  of  mixture  falls  off.  In  analogy,  two  streams  of  water  eminating  from 
nozzles  under  high  pressure,  may  be  opposed  so  as  to  cut  each  other,  when  it  will 
be  found  that  there  will  be  practically  no  intermixture  of  the  water,  or  loss  of 
identity  in  the  streams,  unless  indeed  these  streams  cut  at  a  late  point  where 
their  initial  pressure  is  reduced  through  friction  and  the  streams  are  "  broomed  " 
or  diffused. 

It  will  be  observed  that  while  temperature  is  a  function  of  the  rate  of  combustion 
in  unit  area  times  efficiency  (under  the  latter  term  is  understood  radiation,  intimacy 
of  mixture,  ventilation,  etc.),  the  quantity  of  heat  developed  is  a  function  of  the 
fuel.  However,  as  it  has  been  said,  under  working  conditions  the  amount  of  heat 
is  frequently  dependent  indirectly  upon  temperature,  and  hence  high  temperature 
furnaces,  requiring  a  large  product  of  heat,  are  usually  designed  for  a  high  rate  of 
combustion. 

It  must,  however,  be  borne  in  mind  that  primarily  volume  of  heat  is  dependent 
upon  the  nature  of  the  fuel  and  the  actual  volume  of  heat  developed  from  a  pound  of 
coal  is  identical,  whether  burned  in  a  few  moments  under  forced  draft  or  slowly  oxidized 
through  atmospheric  exposure. 

Combustion. — The  rate  of  combustion  is  frequently  very  much  over-estimated, 
which  condition  is  noted  in  Wm.  Kent's  experiments,  where  he  cites  the  fact  that  a 
low  rate  of  10  Ibs.  of  coal  per  square  foot  of  grate  surface  per  hour  in  fire-brick 
furnaces  produces  so  small  a  radiation  that  it  attains  an  actual  temperature  very 
nearly  as  high  as  that  obtained  by  20  to  40  Ibs.  of  coal  per  square  foot  of  grate  area 
per  hour,  the  loss  in  the  latter  being  due  of  course  to  the  considerable  increment  of 
excess  air  necessary  for  its  combustion. 

Even  with  a  gaseous  fuel,  however,  a  certain  excess  of  air  (above  the  theoretical) 
is  required  for  complete  combustion,  the  percentage  of  air  being  less  in  direct  propor- 
tion to  the  extent  to  which  the  air  is  pre-heated. 

According  to  H.  H.  Campbell,  with  gas  at  600°  C.  and  air  at  50°  C.,  from  20  to 
100%  of  air  in  excess,  is  necessary  to  prevent  the  escaping  of  a  considerable  quantity 
of  combustible  matter  unburned,  although  with  air  and  gas  at  1000°  C.,  the  escape 
of  unburned  combustible  gas  is  reduced  to  10%  and  in  some  instances  5%  in  furnaces 
of  satisfactory  design. 

Again,  we  find  that  with  dust  or  powdered  fuel,  where  the  intimacy  of  the  mixture 
is  thereby  increased  and  the  flame  propagation  made  more  rapid,  combustion  attains 
very  nearly,  if  not  exactly  theoretical  conditions,  and  we  may  allow  with  the  powdered 
coal  about  150  cu.ft.  per  pound  of  combustible. 

It  is  of  course  understood  that  where  an  insufficient  air  supply  exists,  incom- 
plete combustion  and  lower  temperature  must  necessarily  follow  by  reason  of  the 
fact  that  a  portion  of  the  oxygen  passes  through  the  fuel  without  carbon  combina- 
tion. Moreover,  the  air  supply  is  usually  more  or  less  irregular,  even  with  a  nominally 
steady  draft  pressure,  one  reason  being  that  freshly  fired  coal  chokes  to  some  extent 
the  rivers  or  passages  through  the  fuel  bed,  or  in  the  grate,  creating  certain  combina- 
tions of  carbon  monoxide,  and  endothermically  chilling  the  flame. 

Wm.  Kent  obtained  temperatures  exceeding  650°  C.  as  measured  by  a  Uehling 


COMBUSTION   IX   FURNACES 


371 


J  no    Jtoo       2700 

M6£*  CF) 


FIG.  192. — Composition  of  Flue  Gas  compared  with  Furnace  Temperature. 
Curve  No.l=O2;  Curve  No.  2  =  CO2;  Curve  No.  3  =  CO. 


Wo  J 


1950 2050      2T&0       2-J50 
COMBUSTION'CHA 


No 


No. 4 


2860   2450   2560   2050   2750   2860 

MBER  TEMP E RATURE('F) 


FIG  193. — Composition  of  Burned  Gas  in  rear  of  Combustion  Chamber  at  Temperatures  Given. 
Curve  No.  1=CO3,  O2,  and  CO;  Curve  No.  2  =  O2;  Curve  No.  3  =  CO2;  Curve  No.  4  =  CO.  The 
samples  of  gas  were  taken  through  water-jacketed  sampling  tubes. 


GAS   PRODUCERS 


recording  pneumatic  pyrometer,  with  Pittsburg  coal  containing  less  than  2%  of 
moisture  and  having  a  calorific  value  of  15,000  B.T.U.,  in  the  combustion  chamber 
with  fire-brick  linings  and  by  constant  firing  of  small  quantities  of  coal  at  a  time. 

This  approximates  very  nearly  to  theoretical  temperature  due  to  an  air  supply 
of  19  Ibs.  of  air  per  pound  of  combustible,  which  is  the  figure  found  in  practice  to 


O—  —  O  &QS?d  on  Potl  O.3  firf 

::••  :.;  Bosec/  on  JJry  fuel 
ftyvres  onOvrves  iac/icfte  nt, 
-tcrcf/eitsovmij*J.  ftr  given  paint; 

/ 

$ 

m- 

<<G 

* 

t 

r 

4 

4 

•" 

•>» 

•>. 

~^i 

*•> 

^ 

^ 

•^ 

- 

*-~ 

•m,^ 

0  > 

< 

^> 

— 

!£ 

4? 

it1 

—  > 

~., 

* 

| 

— 

*t< 

-*, 

i. 

^ 

VA- 

•^ 

ia 

w 

w 

•^ 

r~ 

', 

toco 


Fia.  194. — Influence  of  Rate  of  Combustion  and  Dryness  of  Fuel  upon  Temperature  (U.  S.  Geol. 

Sur.   Report). 


fen  ef*r  CO/LOIJ 


FIG.  195. — Proportion  of  Losses  Due  to  Imperfect  Combustion  or  Due  to  CO  in  Flue  Gas. 


give  the  highest  efficiency  of  steam-boiler  performance.     (See  Kent's  "  Steam  Boiler 
Economy,"   page   31.) 

Ignition. — Every  fuel  has  a  certain  critical  temperature,  which  is  knowyn  as  its 
•'ignition  temperature,"  to  which  it  must  of  course  be  raised  before  combustion  will 
take  place.  This  naturally  reflects  another  advantage  obtained  from  the  pre-heating 
of  the  elements  of  combustion  and  varies  according  to  their  physical  properties,  chemical 
compositions,  etc.  Under  the  former,  density  is  perhaps  the  most  notable  factor. 
Under  the  latter  it  will  be  noted  that  fuels  which  contain  the  most  hydrogen  are 


COMBUSTION   IN    FURNACES  373 

usually  the  easiest  to  ignite,  resinous  wood  and  cannel  coal  being  examples  of  this 
fact. 

It  may  be  noted,  however,  that  no  gas  will  ignite  below  a  red  heat,  which  fact  is 
true  regardless  of  its  content  of  hydrogen.  This  is  because  of  its  lack  of  density  or 
rather  of  the  diffusion  of  its  molecules. 

Pine  wood  ignites  at  295°  C.;  ordinary  bituminous  coal  at  325°  C.;  coke,  anthra- 
cite, hydrogen,  carbon  monoxide,  etc.,  require  a  dull  red  or  cherry  heat.  (Roberts- 
Austen,  "Introduction  to  the  Study  of  Metallurgy,"  page  171). 

Where  the  temperatures  of  gases  are  maintained  or  lowered  below  ignition  point, 
no  combustion  of  course  takes  place.  This  is  a  principle  involved  in  the  "  Miners 
lamps  "  and  numerous  safety  devices,  also  the  screens  in  Bunsen  burners. 

Nitrogen. — Although  nitrogen  is  considered  an  uninflammable  gas,  Professor 
Lewes  points  out  that  inasmuch  as  it  forms  no  less  than  five  compounds  with  oxygen, 
it  is  evident  that  its  lack  of  combustion  is  due  to  an  inability,  under  ordinary  circum- 
stances, to  produce  a  sufficiently  high  temperature  to  bring  about  direct  com- 
binations. 

Compounds  of  oxygen  and  nitrogen  are  found  in  the  atmosphere  after  thunder 
storms,  and  as  the  result  of  electric  sparks,  and  it  is  likely  that  nitrogen  oxides 
have  much  to  do  with  certain  furnace  conditions  at  high  temperatures,  which  are 
otherwise  unexplainable. 

Professor  Lewes  in  his  work  on  "Liquid  and  Gaseous  Fuels"  (page  8),  points  out 
that  oxidization  and  combustion  are  identical  in  their  total  heat  liberation,  and  differ 
only  in  the  rate  of  chemical  combination. 

Whether  a  tree  decay  or  be  burned,  the  amount  of  heat  evolved  is  identical,  its 
generation  covering  widely  different  periods.  Moreover,  the  distinguishing  demarka- 
tion  between  these  combinations  is  to  a  great  extent  that  of  ignition  point,  phos- 
phorus forms,  igniting  and  combining  with  oxygen  at  a  point  little  above  atmospheric 
temperature;  coal  at  about  500°  C.,  while  steel,  which  is  subject  to  oxidization  in 
the  form  of  rust,  has  so  high  an  ignition  point  as  to  make  it,  for  all  practical  purposes, 
uninflamable.  In  this  connection,  Prof.  Lewes  says  as  follows: 

"  The  spread  of  ordinary  fire  and  flame  is  due  to  the  fact  that  when  combustion 
is  started  by  the  ignition  point  being  reached,  the  combustion  raises  the  temperature 
generally  well  above  the  ignition  point  of  the  burning  body,  so  that  as  one  particle 
burns,  it  ignites  the  next,  and  this  action  continues  until  the  burning  body  has 
entirely  combined  with  oxygen,  but  if  the  heat  generated  be  insufficient  to  raise  the 
body  to  the  ignition  point,  combustion  ceases  as  soon  as  the  external  heat  is  with- 
drawn. In  the  case  of  a  watch  spring  burning  in  oxygen  gas,  the  combustion  of  a 
piece  of  German  tinder  attached  to  the  end  of  it  is  sufficient  under  the  exciting 
influence  of  the  pure  oxygen  to  raise  the  spring  to  the  point  of  ignition,  and  then  the 
temperature  developed  by  the  oxidation  of  the  metal  in  the  oxygen  is  sufficient  to 
continue  the  combustion  until  the  whole  of  the  spring  is  burnt  away.  If,  however, 
instead  of  allowing  the  action  to  go  on  in  the  pure  oxygen  the  spring,  whilst  still  vividly 
burning,  is  withdrawn  from  the  jar  of  oxygen  into  the  air,  combustion  ceases  after 
a  few  moments,  owing  to  the  dilution  of  the  oxygen  in  the  atmosphere  by  nitrogen 
lowering  the  intensity  of  the  combustion,  so  that  the  ignition  point  of  the  metal  is  no 
longer  reached." 


374 


GAS    PRODUCERS 
COMBUSTION   OF   CARBON   DATA 


Condition  of  Bed  with  Reaction  Symbolized. 

Parts  of 
C 
Burned  or 
Oxidized. 

Net  Total  Thermal 
Effect. 

Net  Thermal 
Effect  per  Unit 
of  Carbon  Burned 
Unit=l  Ib.  or  1  kg. 

1.  Shallow  bed  and  complete  combustion,  or 
C  to  CO2  

"oxidation"  of 

12  Ibs. 
12  kgs. 

DEVELOPING 
175766  B.T.U. 
or 
97656  kg.-cal. 

DEVELOPING 
14648  B.T.U. 
or 
8138  kg.-cal. 

Volumes  

I           I 

Reaction  

.  C  +  O2  =  CO2 

Weight  

.  12  +  32  =  44 

2.  Deeper  bed  and  conversion  or  "reduction 
CO  in  the  producer  

"  of  thisCO2to 

12  Ibs. 
12  kgs. 

ABSORBING 

68976  B.T.U. 
or 
38328  kg.-cal. 

ABSORBING 

5748  B.T.U. 
or 
3194  kg.-cal. 

Volumes  

I                 II 

CO2+  C  =  2CO 
44  +12=  56 

Reaction  

Weight  

3.  Direct  oxidation  of  the  C  to  CO;   "primary"  or  incom- 
plete combustion  in  the  producer  

24  Ibs. 
24  kgs. 

DEVELOPING 
106400  B.T.U. 
or 
59328  kg.-cal. 

DEVELOPING 
4450  B.T.U. 
or 
2472  kg.-cal. 

Volumes       

I        II 

2C  +  O2  =  2CO 
24  +  32=  56 

Reaction  

Weight  

4.  Combustion  of  this  CO  to  CO2  in  engine  or  furnace  ;  "sec- 
ondary" or  completed  combustion  

24  Ibs. 
2  kgs.4 

DEVELOPING 
254560  B.T.U. 
or 
136416  kg.-cal 

DEVELOPING 
10231  B.T.U. 
or 
5684  kg.-cal. 

Volumes      

II        I        II 

2CO  +  O2  =  2CO2 
56  +32=   88 

Reaction  .  .          

Weight  .               

Air  for  Combustion. — (Ingalls,  "Metallurgy"):  Theoretically  the  combustion  of 
1  Ib.  of  carbon  to  dioxide  requires  11.52  Ibs.  of  air.  Practically  under  the  ordinary 
conditions  of  chimney  draft  that  quantity  is  greatly  exceeded.  Donkin.  and  Kennedy 
showed  in  the  results  of  sixteen  tests  with  steam-boiler  installations  that  the  air  supply 
ranged  from  16.1  to  40.7  Ibs.  (Walter  B.  Snow,  "  The  Influence  of  Mechanical  Draft 
upon  the  Ultimate  Efficiency  of  Steam  Boilers,"  a  lecture  delivered  before  the 
Engineering  Society  of  Columbia  University,  December  1,  1898.)  The  effects  of  an 
excess  of  air  upon  the  combustion  of  coal  are  to  reduce  the  temperature  produced 
thereby  and  increase  the  relative  weight  of  the  products  of  combustion.  Although 
the  initial  volume  increases  with  the  excess,  however,  it  is  to  be  noted  that  the  relative 
volume  just  after  passing  through  the  fire  remains  practically  constant  because  of 
its  lower  temperature  and  consequently  greater  density.  In  so  far  as  the  temperature 
is  reduced  there  is  a  loss  of  efficiency,  since  the  lower  the  initial  temperature  the  less 
rapidly  will  the  gases  of  combustion  transmit  their  heat,  and  the  final  result  is  that, 
within  practical  limits,  the  temperature  of  the  escaping  gases  is  highest  with  the 
greatest  excess  of  air  supplied. 

In  burning  1  Ib.  of  carbon  to  dioxide  there  are  generated  14,600  B.T.U.  The 
products  of  combustion  comprise  3.667  Ibs.  of  carbon  dioxide  and  8.853  Ibs.  of  nitrogen, 
the  total  weight  being  12.52  Ibs.  Assuming  the  specific  heat  of  carbon  dioxide  to  be 
0.217,  and  that  of  nitrogen  to  be  0.2438,  the  average  specific  heat  of  the  gas  is  0.2359. 
According  to  the  formula  given  in  a  previous  section  the  theoretical  elevation  of 
temperature  of  the  fire  above  the  atmospheric  temperature  would  be  14,600  +  12.52 


COMBUSTION   IN    FURNACES 


375 


X0.2359  =  4942.5°  F.  (2728°  C.).  If  the  atmospheric  temperature  were  62°  F.,  the 
theoretical  temperature  of  the  fire  would  be  4956° +  62°  =  5004. 5°.  It  is  probable 
that  the  specific  heat  of  gases  of  combustion  at  high  temperatures  is  higher  than 
0.2359,  which  would  have  the  effect  of  reducing  the  temperature.  The  actual  specific 
heat  of  combustion  of  the  gases  under  those  conditions  has  not  been  determined, 
but  the  figure  of  0.237  is.  commonly  assumed  in  temperature  calculations.  How- 
ever, because  of  the  excess  of  air  required  to  effect  complete  combustion,  besides  other 
considerations,  it  is  never  possible  to  attain  the  theoretical  temperature.  The  effect 
of  different  percentages  of  air  supply  in  reducing  the  temperature  of  fire  is  shown  in 
the  subjoined  tables  which  are  taken  from  Kent's  treatise  on  "Steam  Boiler  Economy" 
(wherein  they  are  credited  to  H.  T.  De  Puy,  of  the  Babcock  &  Wilcox  Co.)  and  other 
sources : 


EFFECT  OF  AIR   EXCESS  ON   TEMPERATURE 


Air  excess  above  11.52  Ibs.,  %  

25 

50 

75 

100 

150 

200 

\ir  per  pound  of  carbon   Ibs 

14  40 

17  28 

20  16 

23  04 

28  80 

34  56 

Products  of  combustion   Ibs 

15  40 

18  28 

21   16 

24.04 

29  80 

35  56 

Elevation  of  temperature  of  fire,  °  F.  .  .  . 

3950° 

3328° 

2875° 

2530° 

2041° 

1711° 

CARBON  BURNED  PARTLY  TO  CO2  AND  PARTLY  TO  CO,  WITH  EXCESS  OF  AIR 


Excess  of  air,  %  .  .           

50 

40 

30 

20 

10 

0 

Carbon  burned  to  CO2,  %  

100 

80 

60 

40 

20 

0 

Carbon  burned  to  CO,   %  

0 

20 

40 

40 

80 

100 

Products  of  combustion   Ibs                                .... 

18  28 

15  52 

12  99 

10  67 

8  60 

6  76 

Elevation  of  tempernture  of  fire  °  F.  .  .  .             .... 

3328° 

3375° 

3350° 

3323° 

3139° 

2743° 

(Heat  value  of  carbon  assumed  to  be  14,600  B.T.U.  and  specific  heat  of  gases  0.24.) 


EFFECT  OF  AIR   EXCESS  ON   FLUE  LOSSES 


100°  C 

200°  C 

300°  C 

400°  C 

600°  C 

Specific  heat  of  waste  gases: 
No  excess  air  

0  328 

0  336 

0  344 

0  352 

0  367 

90%  excess 

0  327 

0  334 

0  341 

0  348 

0  363 

40%      " 

0  324 

0  331 

0  338 

0  345 

0  358 

60%      " 

0.322 

0.328 

0  335 

0  341 

0  354 

80%      " 

0  320 

0  326 

0  332 

0  338 

0  349 

100%      "         

0.318 

0  324 

0  329 

0  334 

0  345 

Heat  lost  ;  per  cent  of  total  : 
No  excess  air      .  .           .              

% 
3  8 

% 
7  5 

% 
11  3 

% 
15  5 

% 
24  0 

20%  excess                   

4  5 

8  9 

13  4 

18  4 

28  3 

40%      " 

5  1 

10  3 

15  4 

21   1 

32  5 

60%      " 

5.8 

11  7 

17  5 

23  9 

36  8 

80%      " 

6.5 

13  0 

19  5 

26  7 

41  0 

100%      "          

7.2 

14.4 

21  6 

29  5 

45  3 

376 


GAS   PRODUCERS 


DIRECT  COMBUSTION   FURNACE.     EFFECT  OF   SURPLUS  AIR   SUPPLY.    (BUTTERFIELD) 


1 

Volumes   of  air  in  excess   of 
ideal   requirements   for  the 
combustion    of    carbon    to 
carbonic    acid,    present    in 
every    100    volumes  of   air 
supplied  to  the  furnace. 

2 

Volume  under  normal  condi- 
tions of  chimney  gases  for 
the  furnace  per  pound  of 
carbon  consumed. 

3 

Heat     carried     by     chimney 
gases  leaving  the  furnace  at 
975°  C. 

4 

Ratio  of  heat  carried  by  chim- 
ney gases  leaving  the  fur- 
nace   at    975°    C.    to    heat 
furnished   by   the   combus- 
tion of  the  carbon. 

0              

Cubic  Feet. 
143  .  5 

B.T.U. 
5940 

Per  Cent. 
40.8 

1                 

145.0 

5995 

41.2 

2 

146.4 

6050 

41.6 

3   . 

147.9 

6100 

41  9 

4    

149.5 

6160 

42  3 

5   .                 .           .        .  . 

151.0 

6215 

42  7 

7                      .            

154.3 

6330 

43  5 

10  

159.4 

6515 

44.8 

12  

163.1 

6645 

45.7 

15  

168.8 

6855 

47.1 

20  

179.4 

7235 

49.7 

25  

191.3 

7665 

52.7 

30  

205.0 

8155 

56.1 

35  

220.8 

8725 

60.0 

40   

239.2 

9385 

64.5 

45   

260.9 

10170 

70.0 

50  :  

287.0 

11110 

76.3 

DIRECT  COMBUSTION  FURNACE.     EFFECT  OF  INADEQUATE  AIR   SUPPLY. 

(BUTTERFIELD) 


1 

Volumes  of  air 
supplied  stated 
in  percentages 
of  the  volume 
required  to 
form  carbonic 
acid  only  from 
the  carbon  of 
the  fuel. 

2 

Heat  developed  by 
the  combustion  of 
1    Ib.    of    carbon 
with  air  supply  as 
stated. 

3 

Percentage  which 
the  values  in  col- 
umn   2    represent 
the     heat    devel- 
oped by  the  com- 
bustion of  1  Ib.  of 
carbon  to  carbon- 
ic acid  only. 

4 

Volume  under  nor- 
mal conditions  of 
the  chimney  gases 
from   the   furnace 
per  Ib.  of  carbon 
consumed  with  air 
supply  as  stated. 

5 

Heat  carried  by  the 
chimney     gases 
leaving    the    fur- 
nace   at    975°    C. 
(Sensible      heat 
only.) 

6 

Percentage       which 
the  values  in  col- 
umn   5    represent 
of    the    heat    de- 
veloped as  shown 
in  column  2. 

100  
99 

B.T.U. 
14550 
14345 
13940 
13535 
12525 
11515 
10505 
9500 
8490 
6470 
4450 

100 

98.6 
95.8 
93.1 
86.1 
79.2 
72.2 
65.3 
58.4 
44.5 
30.6 

Cubic  Feet. 
143.5 
142.4 
140.1 
137.8 
132.2 
126.5 
120.8 
115.1 
109.4 
98.0 
86.7 

B.T.U. 
5940 
5885 
5773 
5660 
5380 
5095 
4815 
4530 
4250 
3685 
3120 

40.85 
41.04 
41.42 
41.82 
42.94 
44.24 
45.81 
47.71 
50.06 
56.96 
70.12 

97  

95  

90  

85  

80  

75  

70  

60  

50  

COMBUSTION    IX    FUKXACKS 
EFFECT   OF   EXCESS  AIR  ON   BURNING  COAL 


377 


Excess  Ai,,  Per  Cent. 

Hard  Coal. 

Soft  Coal. 

COz,  Per  Cent. 

O,  Per  Cent. 

CO2,  Per  Cent. 

O.  Per  Cent. 

No  excess 

21.0 

19.1 
17.5 
16.1 
15.0 
14.0 
1.3.0 
12.3 
11.7 
11.1 
10.5 

0.0 
1.9 
3.5 

4.8 
6.0 
6.9 
7.8 
8.6 
9.3 
9.9 
10.5 

19.1 
17.3 

15.8 
14.5 
13.5 
12.6 
11.7 
11.0 
10.4 
9.9 
9.4 

0.0 
2.0 

3.6 
4.9 
6.1 
7.1 
8.0 
8.8 
9.5 
10.1 
10.6 

10   

20                                   ... 

:^o                         

40                     

50                      

60                    

70          .             

80  

90        

100  

Imperfect  combustion  results  when  the  carbon  of  a  fuel  is  converted  into  mon- 
oxide CO,  instead  of  into  dioxide  CO2j  the  formation  of  carbon  monoxide  may  result 
either  from  the  direct  oxidation  of  carbon  to  that  product  by  reason  of  insufficient 
air  supply,  or  from  the  reduction  of  carbon  dioxide  by  another  molecule  of  carbon 
according  to  the  equation: 

C02+C  =  2CO. 

The  above  reaction  takes  place  when  the  carbon  dioxide  produced  by  the  combus- 
tion of  carbon  on  the  grate  is  reduced  in  passing  through  a  bed  of  red-hot  coke  by 
another  part  of  carbon.  This  is  a  cooling  process,  in  which  10,150  B.T.U.  are  absorbed 
per  pound  of  carbon  originally  burned  to  dioxide,  wherefore  if  the  reduction  occur 
to  the  extent  that  all  the  dioxide  is  reduced  to  monoxide,  the  heat  generated  by  the 
combustion  of  1  Ib.  of  carbon  is  14,600-10,150  =  4450  B.T.U.  This  reaction  and  its 
thermal  results  are  very  important  considerations  in  producer  work  (See  Chapter  I 
under  Chemical  reactions). 

Oxidizing  and  Reducing  Flames. — An  oxidizing  flame  is  one  which  acts  oxidiz- 
ingly  on  the  body  undergoing  heat  treatment.  This  may  mean  that  a  very  large 
percentage  of  oxygen  is  present,  or  it  may  mean  that  the  percentage  of  oxygen  is 
quite  low.  In  the  manufacture  of  Portland  cement,  an  oxidizing  flame  is  required  to 
thoroughly  oxidize  all  the  iron  present  in  the  cement  to  a  high  stage  of  oxidation, 
in  order  to  get  bluish-black  cement  clinker.  The  percentage  of  oxygen  is,  however, 
quite  different  in  such  a  flame  from  that  used  in  the  manufacture  of  steel,  by  the  open 
hearth  process. 

A  cutting  flame  is  generally  used  to  indicate  a  flame  having  intensely  oxidizing 
properties;  a  very  hot  flame  carrying  a  high  percentage  of  oxygen  is  usually  a  cutting 
flame.  It  is  used  in  the  steel  business  to  indicate  a  flame  which  will  cut  into  a  billet 
of  steel  rapidly,  and  waste  a  great  deal  of  material  by  rapid  oxidation. 

A  reducing  flame  is  the  reverse  of  an  oxidizing  flame,  and  capable  of  reducing  the 
oxides  or  other  materials  which  are  being  heated,  from  a  higher  to  a  lower  stage  of 
oxidation,  or  even  to  complete  reduction  to  the  metallic  state,  if  the  materials  contain 
oxides  of  the  metals.- 


378  GAS    PRODUCERS 

A  soaking  flame  is  a  neutral  or  reducing  flame  having  highly  radiative  properties. 

A  neutral  flame  is  one  which  is  neither  oxidizing  or  reducing,  for  the  particular 
material  which  is  being  treated. 

A  voluminous  flame,  as  used  in  connection  with  Eldred  process,  is  an  expanded 
or  extended  flame;  one  dilated  by  products  of  combustion. 

In  general  these  are  the  definitions  of  the  terms  mentioned,  although  in  certain 
special  arts  there  may  be  a  different  meaning  attached. 

Dowson  defines  a  "  reducing  flame  "  as  "  the  reducing  action  a  gas  has  on,  or 
the  use  of  the  gas  for,  deoxidizing  the  surface  of  a  metal,"  this  being  done  by  reduc- 
ing the  supply  of  air  to  the  gas  below  the  necessary  quota  for  complete  combustion. 
In  this  mariner  a  certain  amount  of  free  oxygen  (enough  to  complete  the  combustion 
of  the  gas)  is  withdrawn  from  the  surface  of  the  metal,  this  "  selection  "  having  a 
reducing  action.  Thus  a  plate  of  bar  iron  placed  in  a  furnace  in  contact  with  an 
oxidizing  flame,  the  surface  will  be  more  or  less  converted  into  magnetic  iron  oxide 
Fe3O4,  but  if  the  bar  had  been  coated  with  rust  Fe203,  or  with  a  scale  of  iron  oxide 
and  were  put  into  a  furnace  heated  by  the  reducing  or  deoxidizing  flame,  the  gas 
would  attack  the  iron  oxide  and  its  carbon  take  to  itself  all  or  part  of  the  oxygen 
contained  in  the  latter. 

Progressive  Combustion  Stages. — Mr.  W.  A.  Bone  has  discussed  the  matter  of 
combustion  in  the  Gas  World  of  April  25th,  1908,  of  which  the  following  is  a  digest:  In 
considering  the  propagation  of  a  flame  through  an  explosive  mixture  of  gases,  it  is 
necessary  to  distinguish  between  two  well-defined  conditions.  When  such  a  mixture 
is  ignited,  the  flame  travels  for  a  certain  limited  distance  at  a  fairly  uniform  slow- 
velocity.  This  initial  stage  of  the  combustion  is  called  "  inflammation."  After 
traveling  a  few  feet,  however,  the  flame  begins  to  vibrate,  the  vibrations  become 
more  intense,  and  then  either  the  flame  is  extinguished  or  it  goes  forward  with  an 
exceedingly  great  and  constant  velocity,  producing  the  most  violent  effects.  This 
new  condition  thus  set  up  is  termed  "  detonation  "  and  the  forward  movement  of  the 
flame,  which  is  sometimes  at  the  rate  of  a  mile  a  second,  is  called  the  "explosive  wave." 

Opinion  has  been  sharply  divided  as  to  the  nature  of  the  combustion  of  a  hydro- 
carbon. During  the  greater  part  of  the  last  century  the  belief  prevailed  that  the 
hydrogen  is  much  more  the  combustible  of  the  two  elements,  and  that,  consequently, 
when  combustion  occurs  in  a  limited  supply  of  oxygen,  the  hydrogen  is  preferentially 
burned.  The  second  theory  held  that  the  carbon  was  burned  to  carbonic  oxide  first,  and 
that  the  excess  of  carbon  divided  itself  between  the  carbonic  oxide  and  the  hydrogen. 

The  idea  of  "  preferential  combustion,"  however,  seems  repugnant  to  well- 
established  principles,  while  the  direct  transformation  from,  say,  ethylene  and  oxygen 
to  carbonic  oxide  and  water,  raises  at  once  serious  difficulties.  It  therefore  remained 
to  consider  whether  the  solution  of  the  problem  might  not  be  in  the  assumption  of 
the  hydrocarbon  and  oxygen  forming  an  unstable  "  oxygenated  "  molecule,  which 
subsequently  rapidly  decomposes.  This  was  indeed  suggested  many  years  ago  by 
Prof.  H.  E.  Armstrong,  but  little  notice  was  taken  of  his  suggestion  at  the  time. 

Investigations  undertaken  by  Mr.  Bone  at  temperatures  from  250  to  400°  C.  afford 
conclusive  evidence  against  preferential  combustion,  whether  of  carbon  or  hydrogen. 
Large  quantities  of  aldehydic  intermediate  products  were  isolated,  and  the  balance 
of  evidence  was  decidedly  in  favor  of  the  "  hydroxylation  "  theory,  with  the  proviso. 


COMBUSTION   IN   FURNACES  379 

however,  that  the  oxygen  is  directly  active.  A  scheme  is  put  forward  for  the  slow 
combustion  of  ethane,  in  which  the  initial  oxidation  product  is  probably  ethyl  alcohol. 
This  oxidizes  to  the  unstable  CH3CH  (OH)2,  which  decomposes  into  steam  and  acetal- 
dehyde.  This  in  turn  is  burned  to  carbonic  oxide,  steam  and  formaldehyde,  and 
finally  to  steam  and  oxides  of  carbon,  probably  through  formic  acid  and  carbonic  acid. 

As  the  temperature  rises,  the  intermediate  products  become  more  and  more 
unstable,  and  to  an  increasing  extent  decompose  into  simpler  products,  which  then 
undergo  independent  oxidation.  Thus  ethyl  alcohol  decomposes  into  ethylene  and 
steam;  acetaldehyde  into  methane  and  carbon  monoxide,  or  into  carbon,  hydrogen, 
methane  and  carbon  monoxide,  according  to  the  temperature;  and  formaldehyde 
is  resolved  into  carbon  monoxide  and  hydrogen. 

With  the  extension  of  the  research  in  regard  to  conditions  existing  in  hydro- 
carbon and  explosions,  it  became  increasingly  evident  that  the  mechanism  of  com- 
bustion is  essentially  the  same  above  as  below  the  ignition  point.  It  is  not  meant, 
of  course,  that  the  phenomena  observed  at  low  temperatures  in  slow  combustion 
are  exactly  reproduced  in  flames,  but  rather  that  the  result  of  the  initial  molecular 
encounter  between  the  hydrocarbon  and  oxygen  is  probably  much  the  same  in  the 
two  cases,  namely,  the  formation  of  an  "oxygenated"  molecule. 

The  above  theories  were  illustrated  and  demonstrated  by  exploding  various 
mixtures  of  hydrocarbons  and  oxygen  in  glass  bulbs,  and  noting  the  invisibility  of 
the  products  of  combustion  in  some  cases,  and  the  appearance  of  free  carbon  and 
moisture  in  the  others. 

FURNACES 

Efficiency. — Under  this  term,  according  to  Richards,  we  must  distinguish  two 
classes,  the  first  referring  to  furnaces  in  which  the  object  is  to  maintain  a  certain 
temperature  for  a  certain  time  with  the  minimum  consumption  of  fuel;  the  second, 
in  which  the  object  is  to  perform  a  certain  thermal  operation  with  the  smallest  con- 
sumption of  fuel.  In  the  first  case,  one  furnace  may  be  compared  with  another,  and 
thus  comparative  efficiencies  calculated;  in  the  second  case  real  or  absolute  efficien- 
cies can  be  also  calculated.  A  few  examples  will  illustrate  this  difference,  which  is 
an  essential  difference  as  far  as  making  calculations  is  concerned. 

Specific  Efficiency. — Whenever  it  is  desired  to  melt  a  metal  for  the  purpose  of 
casting  it,  a  certain  definite  amount  of  heat  must  be  imparted  to  the  metal,  and  the 
ratio  between  this  efficiently  utilized  heat  and  the  heating  power  of  the  fuel  consumed, 
is  the  efficiency  of  the  furnace.  If  the  furnace  is  electric,  the  theoretical  heat  value 
of  the  electric  energy  used  is  the  divisor.  If,  in  addition  to  the  heat  required  to  raise 
the  substances  to  the  desired  temperature,  there  is  also  heat  absorbed  in  chemical 
reactions,  this  amount  can  be  added  in  as  usefully  applied  heat,  and  the  sum  of  this 
and  the  heat  in  the  final  products  be  regarded  as  the  total  efficiently  applied  heat. 
If  a  blast  furnace  takes  iron  ore  and  furnishes  melted  pig  iron,  the  sum  of  the  heat 
absorbed  in  the  chemical  decomposition  of  the  iron  oxide  and  the  sensible  heat  in  the 
melted  pig  iron  is  the  efficiently  applied  heat,  because  it  is  the  necessary  theoretical 
minimum  required;  all  other  items  are  more  or  less  susceptible  of  reduction,  but  these 
are  necessary  items  and,  therefore,  measure  the  net  efficiency.  If  a  dwelling  requires 


380  GAS   PRODUCERS 

200  cu.ft.  of  hot  air  per  minute  at  150°  F.  to  keep  it  at  65°  F.,  while  the  outside  air 
is  at  0°  F.,  the  ratio  of  the  heat  required  to  warm  the  200  cu.ft.  of  air  from  0°  F. 
to  150°  F.,  to  the  calorific  power  of  the  fuel  used  per  minute,  measures  the  specific 
efficiency  of  the  "heater";  the  question  of  whether  this  amount  of  hot  air  keeps  the 
temperature  of  the  rooms  at  65°  F.  is  a  question  of  the  general  efficiency  of  the  con- 
struction of  the  house. 

Cases  of  Generic  Efficiency  (such  are  those  in  which  practically  all  the  heat 
generated  eventually  leaves  the  furnace  by  radiation  or  conduction,  or  useless  heat 
in  waste  gases);  this  is  the  case  when  a  certain  temperature  has  to  be  continuously 
maintained  for  a  given  time,  and  where  the  time  element  is  the  controlling  one,  and 
not  any  definite  amount  of  thermal  work  is  to  be  done.  Examples  are  numerous: 
An  annealing  furnace,  where  steel  castings,  let  us  say,  are  to  be  kept  at  a  red  heat  for 
two  days,  or  a  brick  kiln,  where  several  days'  slow  burning  are  required,  or  a  puddling 
furnace,  where  the  melted  iron  must  be  held  one  to  two  hours  to  oxidize  its  impurities. 
In  all  these  cases  we  may  say  that  one  furnace  keeps  its  contents  at  the  right  heat 
for  the  right  time  with  so  much  fuel,  another  does  the  same  work  with  10  or  25%  less 
fuel,  and  is,  therefore,  10  or  25%  more  efficient;  but  we  cannot,  in  the  nature  of  the 
case,  speak  of  the  absolute  or  specific  efficiency  of  the  furnace,  because  there  is  no 
definite  term,  expressible  in  calories,  to  compare  with  the  thermal  power  of  the  fuel. 

In  many  cases  the  two  efficiencies  are  mixed  in  the  same  process  or  operation, 
and  then  the  calculation  of  absolute  or  specific  efficiency  can  be  made  for  that  portion 
of  the  operation  wherein  a  certain  definite  amount  of  thermal  work  is  done.  Thus, 
in  an  annealing  kiln  50  tons  of  castings  may  be  brought  up  to  annealing  heat  in  24 
hours,  starting  cold,  and  the  heat  absorbed  by  the  castings  compared  with  the 
calorific  power  of  the  coal  burnt  during  this  period,  is  a  measure  of  the  real  efficiency 
of  this  part  of  the  operation.  During  the  rest  of  the  operation,  while  the  castings  are 
simply  kept  at  annealing  heat,  there  can  be  no  calculation  of  the  absolute  or  specific 
efficiency  of  the  furnace,  because  one  of  the  terms  necessary  for  the  comparison  has 
disappeared;  in  that  part  of  the  process  we  can  only  speak  of  relative  efficiency 
compared  to  some  other  furnace  doing  a  similar  operation. 

It  goes,  almost  without  saying,  that  we  can,  of  course,  apply  the  conception  of 
efficiency  in  its  relative  or  general  sense  to  the  whole  operation  or  to  any  part  of  it. 

Hot  gas  efficiency,  according  to  Wyer,  differs  from  the-  cold  gas  efficiency  only 
because  account  is  taken  of  the  sensible  heat  of  the  gas  as  it  leaves  the  producer,  as 
shown  by  this  formula: 

Let  Ec  =  cold  gas  efficiency, 
Eyi  =  hot  gas  efficiency. 
S  =  sensible  heat  of  gas  per  cubic  foot. 
H  =  calorific  power  of  the  gas. 
t  =  temperature  of  atmosphere. 
T  =  temperature  of  gas  as  it  leaves  the  producer. 
Cv  =  volumetric  specific  heat. 

S=(T-f)Cv 

(S 
1+7 

H 


COMBUSTION    IN   FURNACES  381 

Most  modern  producers  supply  hot  gas,  but  it  must  not  be  assumed  on  this 
account  that  the  real  efficiency  of  these  producers  is  their  hot  gas  efficiency.  When 
the  gas  is  used  without  passing  through  a  regenerator,  the  sensible  heat  is  all  available, 
and  the  real  efficiency  is  the  hot  gas  efficiency;  but  when  the  gas  is  used  with  a, 
regenerative  furnace  the  case  is  different,  and  it  seems  probable  that  the  sensible 
heat  is  almost  entirely  wasted,  the  only  result  being  the  higher  temperature  of  the 
chimney  gases.  If  this  theory  is  correct,  then,  for  all  producers  supplying  gas  to 
regenerative  furnaces,  the  only  efficiency  which  need  be  considered  is  the  cold  gas 
efficiency." 

Utilizing  Sensible  Heat. — For  furnace  work,  as  has  elsewhere  been  noted,  the  gas 
should  be  delivered  to  the  combustion  chamber  at  the  earliest  possible  moment,  for 
the  following  reasons. 

1.  The  saving  of  sensible  heat,  otherwise  lost  through  radiation. 

2.  The  condensation  of  certain  condensible  hydrocarbons  which  tend  to  precipi- 
tate upon  a  cooling  of  the  gas  and  a  changing  in  the  vapor  tension;  also,  the  gas  should 
be   conducted  to  a   combustion  chamber  with  the  fewest  possible  bends,   turns  or 
dela}rs,  as  it  is  a  law  of  gas  kinetics  that  any  change  in  either  direction  or  velocity 
of  a  gas,  tends  to  precipitate  its  mechanical  ingredients,  that  is  to  say,  those  heavier 
hydrocarbons  which  are  carried  in  suspense.     These  features  are  necessary  of  observ- 
ance in  order  to  obtain  the  maximum  results  from  the  use  of  producer  gas,  the 
efficiency  of  which,  as  compared  with  direct  firing,  consists  chiefly  in  (a)  the  ability 
to  direct  the  combustion  at  a  critical  or  effective  point  of  the  heating  operation,  (6) 
the  ability  to  perform  complete  combustion  with  very  nearly  the  theoretical  amount 
of  air  required  for  the  chemical  combination. 

In  explanation  of  this  latter  it  is  well  to  remark  that  whereas  in  direct  firing  it 
is  necessary  to  use  an  excess  of  air,  in  some  instances  amounting  to  300%  in  excess 
of  the  theoretical  quota,  the  amount  of  air  necessary  to  burn  C  to  CO  (thereby  creating 
a  potential  gas)  known  as  "  primary  air  "  plus  the  amount  of  air  necessary  to  burn 
the  gas  CO  to  C02  (known  as  secondary  air)  equals  the  theoretical  amount  chem- 
ically required  for  combustion,  and  in  practice  does  not  exceed  theory  by  more  than 
10%. 

It  will  be  seen  therefore  that  the  difference  in  the  amount  of  air  which  must 
be  heated  up  to  the  point  of  theoretical  flame  temperature  in  direct  firing  and  gaseous 
firing,  amounts  in  some  instances  to  290%,  which  would  reflect  a  fuel  difference  of  40 
to  50%, 

Richards  says  that:  "If  the  fuel  itself  or  the  air  which  burns  it  is  pre-heated,  the 
sensible  heat  in  either  one  or  in  both  is  simply  added  to  the  heat  generated  by  the 
combustion  to  give  the  total  amount  of  heat  which  must  be  present  as  sensible  heat 
in  the  products  of  combustion.  The  effect  is  exactly  the  same  as  if  the  heat  developed 
by  combustion  had  been  increased  by  the  sensible  heat  in  the  fuel  or  air  used." 

With  reference  to  the  use  of  producer-gas  in  steel  furnaces,  Campbell  gives  the 
following:  "  The  sensible  heat  of  the  gas  is  regarded  as  a  total  loss,  since  a  rise  in 
temperature  at  the  entrance  flue  of  the  furnace  means  a  similar  and  equal  rise  in 
temperature  for  the  products  of  combustion  escaping  in  the  stack.  It  is  therefore 
important  to  so  adjust  the  calorific  work  of  the  producer  that  the  heat  developed  is 
utilized  in  the  heart  of  the  fire  and  the  escaping  gases  are  kept  as  low  as  possible. 


382  GAS   PRODUCERS 

The  use  of  steam  will  lower  the  temperature,  but  it  must  be  remembered  that  the 
cooling  of  the  upper  part  of  the  fire,  by  steam  from  the  grate,  implies  cooling  of  the 
zones  of  decomposition  and  combustion  to  the  same  degree,  so  that  the  utilization 
of  the  sensible  heat  of  the  upper  surface  of  the  fuel  involves  the  presence  of  an 
increased  amount  of  undecomposed  steam  in  the  gases." 

Where  the  producers  are  used  for  heating  regenerative  steel  furnaces,  he  continues, 
"some  engineers  advocate — with  plausible  and,  at  first  sight,  conclusive  reasons — 
placing  the  producer  near  the  furnace,  under  the  impression  that  thereby  they  have 
the  sensible  heat  of  the  gas.  It  is  true  that  when  the  gas  is  hot,  less  heating  of  the 
gas  chambers  is  required,  and  hence  less  checker-work  will  suffice,  but  this  is  a  small 
matter  and  has  no  bearing  on  the  fuel  economy.  Whatever  is  gained  by  hot  gas  at 
the  incoming  end,  is  lost  on  reversal  in  the  outgoing  products  of  combustion.  More- 
over, a  special  system  of  valves  must  be  used  to  handle  the  hot  gases;  ordinary 
valves  soon  warp  and  leak,  and  water  cooling,  is  not  to  be  thought  of  in  this  case, 
for  this  involves  chilling  the  gas,  which  is  manifestly  opposed  to  the  intent  of  the 
practice  in  question.  With  hot  gas,  the  soot  and  tar  will  be  deposited  in  the  regen- 
erators and  this  is  objectionable.  Cool  gas  is  very  desirable  for  the  preservation  of 
dampers  and  valves.  Hot  gas  does  not  tend  to  economize  energy  since  the  loss  of 
heat  in  the  escaping  products  of  combustion  offsets  the  apparent  gain." 

The  primary  function  of  pre-heated  air  is  to  increase  the  intensity  of  combustion. 
At  a  high  temperature  the  affinity  of  air  for  carbon  is  greater  than  at  atmospheric 
temperature,  and  combustion  will  be  very  much  more  vigorous.  Pre-heated  air  should 
be  used  in  gas-producers  whenever  it  is  possible  to  do  so.  In  producers  used  for 
power  purposes,  the  waste  heat  in  the  gas-engine  exhaust  should  be  used  in  pre-heating 
the  air. 

The  writer  does  not  agree  with  either  of  these  authors.  In  his  opinion  the  state- 
ment by  Mr.  Campbell  should  be  evidently  qualified  by  the  fact,  that  the  sensible 
heat  of  the  gas  is  only  a  loss  where  there  is  a  certain  definite  or  limited  absorption 
of  heat  in  the  operation,  as  is  the  case  in  a  steel  furnace. 

Where,  however,  in  any  continuous  process,  where  the  degree  of  heat  absorption 
in  the  operation  is  uncertain  and  may  be  said  to  be  unlimited,  this  sensible  heat  is 
unquestionably  an  advantage,  and  it  may  be  added  to  the  furnace  temperature,  other- 
wise obtained  under  the  following  conditions.  In  the  opinion  of  the  writer  the  heat 
balance  under  such  conditions  would  be  about  as  follows: 

A  deduction  should  be  made  from  the  normal  heat  value  of  the  gas  at  standard 
conditions  of  temperature,  such  deduction  being  the  difference  due  to  the  expansion 
of  the  gas  between  ti  and  t2.  An  addition  should  be  made  for  the  actual  sensible  heat 
contained  in  the  gas  at  t2,  and  a  deduction  should  be  again  made  for  the  increased 
coefficient  of  heat  absorption,  otherwise  specific  temperature  of  the  products  of  com- 
bustion at  £2- 

This,  however,  will  leave  a  considerable  net  earning  in  favor  of  the  hot  gas.  It  is 
of  course  understood  that  this  is  only  under  conditions  of  furnace  combustion  and 
not  for  engine  purposes,  where  the  cooler  and  concentrated  gas  is  desired. 

In  common  practice  the  recuperation  is  usually  limited  where  the  necessary 
temperature  to  be  secured  for  either  gas  or  air  pre-heat  does  not  exceed  500  to  600°. 
Above  this  point  regenerators  are  usually  used.  Recuperators  when  attempted  at 


COMBUSTION  IN   FURNACES  383 

a  higher  temperature  usually    consist   of  terra-cotta  pipes,  which  are  very  unsatis- 
factory. 

The  burning  of  producer  gas  and  air  should  not  be  attempted  unless  in  operations 
under  a  pressure  of  from  one  to  one  and  one-half  pounds  each;  otherwise,  the  flame 
is  too  easily  extinguished  and  even  a  red  heat  is  reached  with  difficulty. 

The  intensity  of  a  flame  may  be  very  materially  affected  by  the  ratio  of  primary 
to  secondary  air  (the  amounts  being  inverse).  Intensity  is  created  through  the 
total  combustion  with  primary  air,  while  the  flame  becomes  more  lambient  by  decreas- 
ing the  primary  and  increasing  the  secondary. 

Size  of  Tuyeres. — The  expansion  of  aii  by  heat  is  0.002036  of  its  volume  for 
each  Fahrenheit  degree,  or  about  1%  for  each  5°  F.,  conversely,  its  pressure  is  increased 
in  that  ratio,  its  volume  remaining  constant.  Therefore,  100  cu.ft.  of  air  at  62°  F., 
when  raised  to  900°  F.  expands  to  270  cu.ft.  under  the  same  pressure. 

To  admit  a  given  amount  of  air  to  a  furnace,  under  a  given  pressure,  the  cross- 
section  area  of  the  tuyeres  must  be  2.7  times  as  great  when  the  air  is  blown  in  at 
900°  F.  as  when  it  is  blown  in  at  62°  F. 

Thus  a  tuyere  3  ins.  in  diameter  will  admit  as  many  pounds  of  air  at  62°  F., 
under  a  given  pressure,  as  one  4.9  ins.  diameter  at  900°,  omitting  difference  in  friction. 
A  furnace  blown  through  tuyeres  of  a  given  size,  with  air  at  900°  F.,  gets  but  37% 
as  much  in  weight  of  air  as  when  blown  through  the  same  tuyeres  at  62°  F.,  the  pressure 
in  each  case  being  the  same. 

Heat  Recuperation  Furnaces. — The  great  step  in  advance  which  was  made  in 
the  introduction  of  the  Siemens  system  of  gas  firing  was  not  in  the  producers,  but 
in  the  scientific  and  well  developed  system  of  recuperating  heat  from  the  waste 
products  of  combustion.  The  Siemens  system  continues  in  use  at  the  present  time 
in  substantially  its  original  form.  To  a  less  extent  counter-current  recuperators  are 
employed,  which  are  also  an  old  invention,  the  principle  dating  back  to  the  time  of 
Gaillard  &  Haillot,  Lencauchez,  Ponsard,  Charneau  and  Nehse.  All  these  are  systems 
of  true  heat  recuperation,  i.e.,  they  recover  it  from  gases  which  would  otherwise  waste 
it,  and  do  not  abstract  it  from  the  fire-box  or  combustion  chamber  of  the  furnace, 
although  the  mere  transference  of  heat  in  that  manner,  as  exemplified  in  the  well 
known  Boetius  furnace,  may  be  highly  advantageous. 

The  terms  "regenerative  furnaces"  and  "recuperative  furnaces"  are  commonly 
employed  to  designate  different  types,  the  former  being  applied  to  the  Siemens  system 
and  the  latter  to  the  continuous  or  counter-current  system;  it  is  generally  safe  to 
infer  that  such  a  distinction  is  made  when  the  two  expressions  are  used  in  metallurgical 
literature,  but  not  always.  More  exactness  is  desirable.  The  terms  "heat  regenera- 
tion" and  "regenerative  furnaces"  are  misnomers.  Regeneration  implies  a  recre- 
ation of  heat,  which  does  not  take  place  in  such  a  furnace,  the  heat  wasted  from  the 
combustion  chamber  being  simply  restored  thereto.  Recuperation,  or  recovery, 
expresses  the  precise  meaning  as  to  what  is  effected  in  both  types  of  furnaces.  The 
two  systems  can  be  appropriately  and  exactly  designated  as  the  "reversing  recupera- 
tion" and  "continuous  recuperation"  of  heat. 

Siemens  Regenerative  System.— In  the  Siemens  system  of  heat  recuperation 
the  hot  products  of  combustion  are  made  to  pass  through  chambers  filled  with  fire- 
brick in  the  form  of  a  checker-work,  to  which  they  impart  a  large  portion  of  their 


384 


GAS   PRODUCERS 


heat.  In  the  meanwhile  the  air  and  gas  for  combustion  enters  the  furnace  through 
a  similar  pair  of  chambers  filled  with  brick  checker-work.  After  a  certain  time,  say 
30  minutes,  the  direction  of  the  gases  is  reversed  by  the  valves  illustrated.  The 
products  of  combustion  are  then  caused  to  pass  out  through  the  two  cooled  chambers, 
while  the  air  and  gas  enter  through  the  two  which  have  become  highly  heated,  the 
gas  passing  through  one  and  the  air  through  the  other.  The  respective  chambers 
for  gas  and  air  are  sometimes  made  of  the  same  size,  but  more  commonly  are  designed 


FIG.  196. — Horizontal  and  Vertical  Cross-section  of    a    Siemens    Regenerative    Furnace    as    Used    at 

Freiburg. 


according   to   the    relative   volumes   of   the   gas   and   air   and   their    heat    absorbing 
capacities. 

The  extent  to  which  heat  may  be  recuperated  by  the  Siemens  system  depends 
upon  the  temperature  of  the  combustion  products  discharged  into  the  recuperative 
chambers,  the  arrangement  and  dimensions  of  the  latter,  the  speed  of  the  gases  in 
passing  through  them  and  the  length  of  time  between  reversals.  By  giving  the 
chambers  a  sufficient  volume  and  the  hot  gases  a  slight  velocity  they  may  be  made 
to  issue  comparatively  cold,  while  the  fresh  air  and  gas  may  be  raised  correspondingly 
to  a  high  degree  of  temperature.  According  to  Friedrich  Siemens,  the  weight  of  the 
brick  filling  of  each  pair  of  regenerators  should  be  theoretically  16  to  17  times  the 


COMBUSTION   IN   FURNACES 


385 


FIG.  197. — Vertical  Cross-section  through  Entrance  Port  of  Siemens  Furnace. 


AR 


FIG.  198. — Horizontal  Section  through  Flues  under  Checkers  and  through  Checker-Brick  Chambers. 


386 


GAS   PRODUCERS 


weight  of  the  coal  burned  between  two  reversals  in  order  to  take  up  all  the  heat  of 
the  gases  of  combustion.  Consequently  in  the  combustion  of  1000  Ibs.  of  coal  per 
24  hours,  or  about  42  Ibs.  per  hour,  there  should  be  17X42  =  714  Ibs.  of  brick  in  each 
pair  of  regenerators  when  the  gas  currents  are  reversed  at  intervals  of  one  hour;  and 
about  360  Ibs.  at  half-hour  intervals.  In  practice,  however,  the  whole  checker-work 
is  not  heated  and  cooled  uniformly,  but  by  far  the  larger  part  of  its  depth  is  required 


FIG.  199. — Sections  of  Siemens  Furnace  showing  Flues  and  Reversing  Valves. 

to  effect  the  gradual  cooling  of  the  products  of  combustion  and  only  a  small  portion 
near  the  top,  perhaps  a  fourth  of  the  whole  mass,  is  heated  uniformly  to  the  full 
temperature  of  the  flame,  the  heat  of  the  lower  portion  decreasing  gradually  down- 
ward nearly  to  the  bottom.  Three  or  four  times  as  much  brick-work  is  therefore  required 
than  is  equal  in  heat  capacity  to  the  products  of  combustion. 

The  size  of  the  chambers  is  commonly  calculated  according  to  the  superficial 
area  that  is  exposed.  Siemens  considered  that  each  pair  of  chambers  should  expose 
51  square  meters  per  1000  kgs.  of  coal  burned  per  24  hours,  or  about  6  sq.ft.  per  pound 
per  hour.  According  to  Roberts-Austen,  in  order  to  insure  that  the  gas  shall  not 


COMBUSTION   IN   FURNACES 


387 


escape  to  the  chimney  at  a  temperature  higher  than  150°  C.  there  should  be  7  to  7.5 
sq.ft.  of  brick  surface  for  every  pound  of  coal  burned  between  reversals  in  direction. 
The  brick  should  be  arranged  in  the  chambers  so  as  to  leave  as  much  space  free  as  full, 
i.e.,  they  should  not  occupy  more  than  50%  of  the  volume  of  the  chambers.  The 
arrangement  of  the  chamber  should  be  such  as  will  compel  the  gas  to  travel  uniformly 
through  all  parts  of  it,  preventing  any  tendency  on  its  part  to  take  the  most  direct 
course,  short-circuiting,  so  to  speak,  and  avoiding  dead  corners.  Siemens  considered 


FIG.  200. — Another  Arrangement  of  Reversing  Flues  and  Valves. 


that  the  chambers  were  best  arranged  vertically,  heating  from  the  top  downward. 
For  various  reasons  it  is  preferable  to  put  the  chambers  beneath  the  hearth  of  the 
furnace  when  that  can  be  done  conveniently.  The  velocity  of  the  gas  through  the 
checker-work  may  be  1  to  2  m.  (3.3  to  6.6  ft.)  per  second.  In  good  practice  the 
escaping  products  of  combustion  are  cooled  down  to  about  300°  C. 

Furnace  Design. — Under  the  head  of  "  Furnaces,"  Ingalls,  in  his  "  Metallurgy 
of  Zinc  and  Cadmium,"  page  263,  says  as  follows: 

"  The  ultimate  analysis  of  a  fuel  being  known,  i.e.,  its  percentage  of  carbon, 


388  GAS   PRODUCERS 

hydrogen,  sulphur,  nitrogen,  etc.,  the  weight  and  volume  of  the  air  required  for  its 
combustion,  and  the  weight  and  volume  of  the  gases  that  will  be  produced,  can  be 
calculated  just  as  in  the  case  of  any  chemical  reaction  and  by  the  same  rules.  In 
designing  a  furnace  for  metallurgical  purposes  in  which  the  combustion  of  fuel  is 
so  highly  an  important  matter  as  it  is  in  the  distillation  of  zinc  ore,  it  is  evident  that 
in  order  to  obtain  the  maximum  efficiency  the  proportions  of  the  furnace,  including 
the  grate  area,  the  volume  of  the  laboratory  or  combustion  chamber,  and  the  area  of 
the  flues  and  chimney  and  the  height  of  the  last,  should  be  planned  with  reference 
to  the  volume  of  the  gases  that  must  pass  through  them,  their  temperature  and  other 
factors.  However,  this  is  but  rarely  done,  not  merely  in  the  design  of  zinc-smelting 
furnaces,  but  in  all  other  kinds  of  metallurgical  furnaces,  and  indeed  the  subject  has 
been  as  yet  studied  so  imperfectly  by  metallurgists  that  much  of  the  data  that  is 
required  for  such  calculation  is  still  lacking.  The  design  of  metallurgical  furnaces  in 
accordance  with  well  known  physical  laws  has  not  yet  been  attempted,  except  in  few 
instances,  and  naturally  little  is  to  be  found  with  respect  thereto  in  existing 
metallurgical  treatises." 

The  furnace  in  present  day  industrial  practice  is  varied  in  class  and  in  nature 
of  operation.  For  general  purposes  they  may  be  divided  into  open  hearth,  muffle, 
crucible,  and  reverbatory,  the  function  of  the  first  being  the  direct  contact  of  the 
contents  of  the  gases  in  combustion,  the  second  being  indirect,  the  heat  being 
delivered  by  conduction  and  convection,  the  third  largely  the  utilization  of  convected 
or  radiant  heat,  and  the  fourth,  the  use  of  heat  reflecting  surfaces  for  decreasing 
the  velocity  of  radiation  and  reflecting  instant  heat  rays  back  to  a  point  where  they 
may  be  reused. 

In  regard  to  the  surfaces,  these  may  require  either  alternately  high  and  low 
temperatures,  as  in  the  case  of  reheating  furnaces,  or  to  give  temperate  temperatures 
at  different  conditions  of  the  hearth,  as  instanced  in  glass  furnaces,  or  again  to  give 
different  temperatures  in  various  compartments,  an  example  of  which  will  be  found  in 
the  Hoffman  furnace  for  bricks,  potteries,  and  ceramic  work. 

The  design  of  furnaces  must  take  into  consideration,  first,  the  nature  of  the  gas, 
including  its  calorific  value,  and  that  of  its  explosive  mixture,  the  pressure  at  which 
it  may  be  expediently  supplied,  the  elevation  above  sea-level  (exceeding  1000  ft.)  the 
temperature  to  be  attained  and  maintained,  the  volume  of  heat  required  (a  function 
of  the  amount  of  fuel  to  be  gasified),  the  radiation  of  the  furnace  walls,  the  nature, 
size,  and  material  of  the  contents  to  be  heated. 

Fuel  Required. — No  definite  rule  can  be  given  for  the  design  of  these  furnaces, 
their  conditions  and  requirements  being  so  widely  varied,  but  as  a  "rule  of  thumb" 
for  estimating  or  checking  and  for  rough  purposes  of  approximation,  the  following 
figures  per  pound  of  coal  used  in  common  practice  of  various  classes  of  furnaces  are 
herein  tabulated. 

750  Ibs.  of  coal  per  ton  of  steel  in  open  earth  furnaces. 

1000  to  1500  Ibs.  of  coal  per  ton  of  steel  in  crucible  furnaces. 
700  to  1000  Ibs.  of  coal  per  ton  of  steel  in  annealing  furnaces  for  castings. 
200  to     300  Ibs.  of  coal  per  ton  of  steel  in  annealing  furnaces  for  sheets. 
450  Ibs.  of  coal  per  ton  of  steel  for  sheet  and  pair  furnaces. 
200  to     300  Ibs.  of  coal  per  ton  of  steel  in  reheating  furnaces. 


COMBUSTION   IX   FURNACES 


389 


200  to  250  Ibs.  of  coal  per  ton  of  steel  in  tempering  furnaces. 
150  Ibs.  of  coal  per  barrel  of  clinker  in  rotary  cement  kilns. 
50  Ibs.  of  coal  per  barrel  in  rotary  kilns  for  calcining  lime. 
One  ton  per  pot  per  24  hours  in  deep  eye-glass  furnaces,  assuming   each   pot   to 
hold  2000  Ibs.  of  flint  gas. 

The  above  figures  of  course  widely  vary,  the  variables  in  the  operation  being  the 
efficiency  of  the  furnace,  which  in  turn  is  dependent  upon  (a)  ventilation,  (6)  radiation. 
Under  the  first  efficiency  produces  a  back  pressure  or  blanketing  of  the  flame,  while 
an  excess  creates  only  an  excess  of  air  through  leakage,  but  an  over-rapidity  in  the 
velocity  of  the  gases,  leaving  an  insufficient  time  contact  for  their  deposit  of  sensible 


FIG.  201. — Reversing  Valve  for  Siemens  Furnace. 


heat  and  expelling  the  gases  at  atmosphere  at  an  uneconomical  height  of  temperature. 
In  furnace  work,  of  course,  a  maximum  of  efficiency  is  reflected  by  the  formula 
TI  —  T%,  the  first  being  the  highest  initial  temperature  and  the  last  final  temperature, 
under  ideal  conditions  the  gases  being  dsicharged  to  atmosphere  at  practically  atmos- 
pheric temperature.  The  ideal  draft  would  therefore  be  the  removal  of  the  gases 
at  a  rate  about  equal  to  the  intake  of  the  elements  of  combustion. 

Conditions  of  radiation  will  be  seen  in  various  forms.     For  instance,  various  sizes 


390  GAS   PRODUCERS 

of  the  same  type  of  furnace  may  be  found  to  vary  in  efficiency  and  is  often  found 
that  by  doubling  the  sides  of  a  furnace,  a  considerable  increased  economy  is  effected. 
This  may  be  laid  to  two  reasons. 

First,  the  larger  furnace  required  the  heavier  and  thicker  walls  to  support  a 
greater  weight  and  span  of  roof.  This  has  reduced  the  radiation  by  reason  of  thick- 
ness. Again,  it  must  be  remembered  that  the  radiating  surface  does  not  vary  as 
the  volume  of  content,  this  being  about  proportional  to  the  square  and  cube  respect- 
ively of  the  linear  dimensions. 

Coal  and  Gas  Firing. — Butterfield  notes  a  range  of  temperature  within  a  furnace 
heated  by  direct  firing  of  an  extreme  difference  of  400°.  This  difference  under  condi- 
tions of  good  design  with  gas  firing,  will  not  exceed  200°  C.  Euchene  found  the 
maximum  temperature  of  a  direct-fired  furnace  to  be  1375°  C.  the  products  of  com- 
bustion leaving  the  furnace  at  975°  C.,  the  heat  duty  reflected  by  this  differential  of 
temperature  or  "drop"  being  approximately  24%.  In  a  regenerative  setting  the 
maximum  temperature  was  1250°  C.,  the  products  of  combustion  escaping  the  recup- 
erator at  1050°  C.,  showing  a  heat < duty  of  13.10%. 

This  would  apparently  show  a  thermal  advantage  upon  the  part  of  the  direct- 
fired  furnace,  the  total  heat  abstraction  being  greater  upon  its  part.  It  however  only 
indicates  a  concentration  of  heat  abstraction,  such  abstraction  being  unequal  and 
localized,  for  Euchene  further  notes,  upon  a  Siemens  alternating  recuperative  set, 
that  in  traversing  the  recuperator  the  temperature  fell  from  1050°  C.  at  the  outlet 
of  the  furnace  to  600°  at  the  outlet  of  the  recuperator.  Hence  the  total  drop  in  the 
temperature  in  the  furnace,  plus  the  recuperator  combined  (and  which  from  an 
economic  standpoint  must  be  taken  as  a  whole),  was  from  1250  to  600°  C.,  a  total 
abstraction  of  650°,  showing  a  heat  duty  or  thermic  efficiency  of  43.3%,  or  a  gain  in 
absolute  working  economy  of  230%  (approximately).  Even  this  terminal  temperature 
is  excessive  and  could  be  materially  reduced  by  additional  heat  absorbing  and  regen- 
erative surface,  with  commensurate  economy.  Taking  these  figures,  however,  not 
only  does  this  comparison  show  an  efficiency  of  more  than  double  that  of  the  direct- 
fired  furnace,  but  the  abstraction  of  the  heat  is  more  gradual  and  uniform,  the  cycle 
possessing  less  irregularities  or  severe  variations. 

Igniting  the  Furnace. — Great  care  should  be  taken  in  lighting  any  gas  furnace 
that  the  light  be  applied  before  the  gas  is  turned  on,  and  that  the  admission  of  the 
gas  be  very  slow  and  never  complete  until  a  small  portion  is  already  ignited.  This 
is  best  accomplished  by  throwing  into  the  furnace  a  small  portion  of  burning  waste, 
flaming  wood  or  other  material,  after  which  the  gas  should  be  gradually  turned  on. 

The  failure  to  observe  this  rule,  obvious  though  it  may  be,  is  the  cause  of  nearly 
every  explosion  and  the  consequent  loss  of  both  life  and  property. 

Where  gas  and  air  are  admitted  to  the  burner  or  combustion  chamber  at  different 
temperatures,  they  should,  unless  injected  as  inductors,  be  entered  with  the  colder 
of  the  two  on  top.  This  is  for  the  reason  that  on  account  of  the  heat  convection  of 
the  warmer  and  gravity  of  the  colder  gas,  there  is  a  tendency  for  a  better  or  more 
intimate  mixture. 

Reverberation  of  Heat. — It  is  of  course  a  known  law  that  the  amount  of  heat 
obtained  in  any  combustion  furnace  is  equal  to  the  total  heat  evolved  by  combustion 
within  unit  space,  less  the  radiation  and  loss  by  ventilation.  In  one  instance 


COMBUSTION    IN   FURNACES 


391 


observed  a  furnace  was  equipped  with  a  circular  baffle  or  bridge  wall,  after  the 
manner  of  a  reverberatory  furnace,  the  flame  occurring  at  about  the  center  of  its 
circle. 

Now,  not  only  would  a  cone  or  pyrometer  placed  within  this  axis  be  the  recipient 
of  the  flame  as  directly  impinged  upon  it,  but  also  the  reflected  heat  returned  by  the 
baffle  or  bridge  wall  and  converged  upon  it. 

In  other  words,  the  circular  fire-brick  baffle  or  bridge  wall  acted  as  a  heat  reflector, 
the  angle  of  reflection  being  equal  to  the  angle  of  incident,  the  result  obtained  was 
a  singular  example  of  heat  conservation,  whereby  not  only  was  the  ventilation 
retarded  but  a  large  portion  of  the  retarded  heat  reflected  and  returned  to  the  area 
of  usefulness.  A  diagram  showing  the  above  arrangement  is  herewith  appended. 

It  will  be  noted  that  for  practical  purposes  the  heat  developed  in  this  furnace 
will  be  probably  one  third  less  than  would  be  indicated  by  a  pyrometer  located  at 
the  heat  axis,  the  distribution  throughout  the  furnace  being  necessarily  very  unequal. 


FIG.  202. — Illustrating  the  Reflection  or  Reverberation  of  Heat. 


Dehydration  of  Blast  Air. — The  possibility  or  rather  the  practicability  of 
dehydrating  blast  air  for  water  gas  sets  is  herewith  tentatively  suggested  as  a  means 
for  promoting  fuel  economy,  increasing  the  capacity  of  the  apparatus,  and  reducing 
the  power,  and  facilitating  the  operation  of  the  sets. 

Blast-furnace  Results. — The  conclusion  has  as  its  basis  the  very  successful 
results  obtained  in  blast  furnace  practice,  an  example  of  which  is  herewith  cited  as 
extracted  from  the  report  of  Joseph  H.  Hart,  Ph.D.,  upon  the  Isabella  furnace  at 
Aetna,  Pa.,  showing  the  following  significant  figures: 

The  Isabella  furnace  at  Aetna,  Pa.,  produced  350  tons  of  iron,  consumed  2147 
Ibs.  of  coke  and  required  40,000  cu.ft.  of  air  per  minute.  They  installed  two  ammonia 
compressors  of  225  tons  of  ice  melting  capacity,  one  used  as  a  stand-by  and  for  peaks. 

The  air  was  cooled  from  80  to  28°  F.  or  reduced  52°.  The  consequent  reduction 
of  moisture  averaged  from  5.66  grains  per  cubic  foot  to  1.75  or  an  elimination  of  3.91 
grains  per  cubic  foot. 

The  results  obtained  by  this  was  that  the  quantity  of  air  was  reduced  to  34,000 


392  GAS   PRODUCERS 

cu.ft.  per  minute,  or  a  saving  of  6,000  cu.ft.  per  minute,  a  reduction  of  about  15%, 
this  being  due  to  increased  density  of  the  air  handled. 

The  blowers  were  slowed  from  114  to  96  r.p.m.,  a  reduction  of  18  r.p.m.  The 
consequent  reduction  in  horsepower  being  from  2700  to  2013  or  687  h.p.  The  refrig- 
erating apparatus  required  about  530  h.p.  and  there  is  still  a  net  saving  in  power  of  157 
h.p.  when  operated  at  maximum  capacity. 

The  moisture  contained  in  air  which  passes  through  the  furnace  was  approximately 
40  gallons  of  water  per  hour,  at  times  being  increased  to  300  gallons,  due  to  variabil- 
ity in  humidity,  wiiich  is  very  wide,  especially  in  some  locations.  About  10  tons  of 
water  per  day  was  extracted  and  the  output  increased  to  450  tons  of  iron,  a  gain 
of  100  tons  or  about  28%.  The  coke  consumption  was  reduced  from  2147  to  1729 
Ibs.,  a  saving  of  418  Ibs.  per  ton  of  iron  output,  or  roughly  speaking  20%. 

Water  Gas. — The  argument  for  the  use  of  dehydrated  air  in  connection  with 
water  gas  sets  would  be  as  follows: 

First,  a  reduction  of  fuel  due  (a)  to  reduced  blasting  period  by  reason  of  the 
denser  quality  of  the  air,  and  resulting  high  flame  temperature  subtending  a  saving 
in  loss  by  radiation,  abstraction  of  heat  by  aqueous  products  of  combustion,  etc. 

The  increase  of  capacity  of  the  sets  is  manifestly  due  to  the  higher  flame  temper- 
ature in  the  combustion  of  the  fuel  in  the  dryer  and  denser  air;  hence  shortening 
of  blast  period  and  permitting  an  increased  duty  nerformed  by  the  apparatus  during 
the  time  unit. 

The  saving  in  power  would  likely  occur  in  the  handling  of  a  denser  air,  and  the 
relief  from  handling  the  additional  weight  of  water.  It  is  by  analogy  that  blast 
furnace  figures  would  show"  some  increment  or  net  economy  over  and  above  the  power 
required  for  the  ammonia  compressors.  In  any  event  the  reduction  in  duty  per- 
formed by  the  speed  of  the  fans  would  at  most  prove  a  stand-by  for  the  outlay  of 
power  for  the  compressors. 

With  regard  to  facility  of  operation  and  general  efficiency,  it  is  extremely  likely 
that  with  the  dryer  and  denser  air  the  blast  pressure  could  be  materially  reduced, 
and  that  there  would  be  a  consequent  reduction  of  channeling  and  chimneys  through 
the  fuel  bed;  hence  a  lessening  of  clinkering  with  a  consequent  necessity  of  difficult 
stoking. 

It  is  also  probable  that  the  dry  air  would  involve  conditions  of  more  equal  heat 
throughout  the  entire  fuel  bed,  inasmuch  as  that  under  ordinary  conditions  the  strata 
of  fuel  in  first  contact  with  the  humid  air  is  chilled,  its  heat  being  abstracted  while 
the  succeeding  strata  are  overheated  from  the  lack  of  this  endothermic  connection 
and  the  combustion  of  the  gases  which  it  forms. 

This  condition  of  equal  heat  throughout  the  fuel  would  make  a  minimum  of 
clinker  formation,  and  a  maximum  of  gas-making  efficiency  if  the  fuel  is  relieved  of  the 
"deadening"  influence  of  the  aqueous  vapor  prior  to  the  steam  injection. 

The  above  argument  seems  at  least  worthy  of  consideration.  It  is  understood 
of  course,  that  the  efficient  operation  of  such  a  plant  would  require  work  of  such  size 
as  to  maintain  a  fairly  high  load  factor  upon  the  blast  air,  that  is  to  say,  the  lay-out 
of  sets  should  be  such  as  to  produce  by  their  rotation  intervals  as  nearly  as  possible 
of  constant  demand  upon  the  blast.  This,  although  not  absolutely  indispensible, 
would  tend  to  the  maximum  efficiency  of  the  plant  proposed. 


COMBUSTION   IN   FURNACES 


393 


Cooling    Plant. — A  tentative  lay-out  of  the  foregoing  arrangement  is  herewith 
illustrated. 


ONI*  CONDENSER 


nnr-i  n  n  n 


CORK  I.NSULATIOK 


15  SECTIONS  OF  2  EXPANSION  PIPE 
30    PIPES  HJGH  20'  LONG 


"^CONCRETE 

DRAIN  TO  SEWER 


CORK  INSULATIOt 


FIG.  203. — Refrigerating  Plant  for  Condensing  Moisture  in  Blast  Air. 


394  GAS   PRODUCERS 

Testing  for  Explosive  Mixture. — In  purging  pipes  or  apparatus  from  gas  for 
testing,  whether  all  air  had  been  expelled  from  newly  installed  gas  chambers,  it  is 
sometimes  desirable  to  test  by  means  of  ignition.  In  case  there  is  enough  gas  or  air 


FIG.  204. — Safety  Device  in  Testing  Gas  when  Filling  new  Holders  or  Mains. 

present  to  form  an  explosive  mixture,  the  results  may  be  disastrous.  In  such  cases 
it  is  -better  to  connect  two  dip  seals,  as  shown  in  Fig.  204,  and  ignite  the  burner 
attached  to  the  fitting  on  the  right  hand  side.  If  the  mixture  is  explosive,  it  will  then 
not  strike  back  further  than  the  jar. 

Steel  Melting  Furnace  Practice. — In  very  high  temperature  meiting  operations 
fairly  high  per  cent  of  hydrocarbons  is  necessary,  owing  to  the  fact  that  it  gives  a  more 
luminous  flame,  and  so  intensifies  the  radiation  from  the  roof  of  the  furnace,  hence 
obtaining  a  higher  reverberation  and  greater  heat  concentration. 

The  flame  temperature  of  the  explosive  mixture  of  constituents  of  the  volatile 
matter  of  coal  possesses,  of  course,  a  somewhat  higher  flame  temperature  than  the 
corresponding  explosive  mixture  of  oxygen  and  carbon. 

The  best  practice  in  steel  making  is  33%  volatile  matter,  and  not  over  10  or 
12%  ash.  25%  volatile  matter  would  be  the  lower  limit. 

Pure  slack  is  inadvisable  on  account  of  the  choking  of  the  blast,  and  the  necessary 
high  pressure  to  overcome  its  resistance. 

In  the  above,  mechanical  feeding  is,  of  course,  presupposed,  in  order  to  obtain 
an  equalization  of  distillation. 

Carbonic  Acid. — There  is  always  a  certain  amount  of  CO2  formed,  even  in  the 
best  practice;  in  fact,  it  is  inevitable,  and  if  kept  within  proper  limits  does  not 
constitute  a  net  loss  of  efficiency,  especially  with  very  short  gas  flues,  because  the 
energy  of  the  fuel  so  burned  is  represented  in  the  sensible  heat  or  temperature  of 
the  gas,  and  results  in  delivering  a  hot  gas  to  the  furnace,  and  the  flame  is  made 
more  voluminous  and  combustion  less  localized.  However,  the  loss  increases 
rapidly  above  4%  of  CO2,  even  when  the  gas  is  carried  hot  in  short  flues.  If  too 
hot,  the  hydrocarbons  are  broken  up  and  deposit  their  carbon  as  soot,  or  lampblack, 
and  the  loss  from  radiation  is  material.  If  an  attempt  is  made  to  run  too  cool,  by 
increasing  the  proportion  of  steam,  the  result  is  equally  bad,  as  a  low  gas  tempera- 


COMBUSTION   IN   FURNACES  395 

ture  permits  the  deposition  of  tar  in  the  flues,  and  both  the  heating  value  and  capacity 
are  largely  reduced. 

The  best  result  in  steel  practice  is  at  about  ±%  CO2,  a  gas  temperature  between 
1100  and  1200°  F.,  and  flues  less  than  100  ft.  long. 

Flues. — It  is  necessary  to  provide  an  ample  flue  capacity  and  to  carry  the  full 
area  right  up  to  the  furnace  ports,  which  latter  may  be  slightly  reduced,  or  con- 
stricted, to  give  the  gas  a  forward  impetus,  and  concentrate  the  gas.  Generally 
speaking,  the  net  area  of  a  flue  should  be  not  less  than  one-sixteenth  of  the  area 
of  the  interior  cross-section  of  the  producers  supplying  it.  Or  the  carrying  capacity 
of  a  hot  gas  flue  should  be  equivalent  to  1  sq.ft.  of  cross-section  per  200  Ibs.  of  good 
coal  per  hour.  Hence,  a  brick-lined  flue  4  ft.  diameter  inside  the  lining  will  carry 
the  gas  made  from  2500  Ibs.  of  coal  per  hour  (12.5  sq.ft.  X  200),  and  will  serve  a 
gas-making  area  of  200  sq.ft.  (12.5X16),  which  corresponds  to  four  8-ft.  producers. 

Sulphur. — Over  1%  of  sulphur  usually  gives  trouble.  Below  that  it  is  prac- 
tically harmless;  2%  is  considered  the  metallurgical  limit.  3%  is  the  operating 
limit  in  most  furnaces. 

A  certain  percentage  of  sulphur  is  residuual  in  the  ash  of  a  producer.  Hence 
the  sulphur  content  permissible  is  higher  in  coal  than  in  oil  where  the  total  sulphur 
is  burned  within  the  furnace. 

The  statement  concerning  the  harmless  effect  of  a  sulphur  element  in  producer 
gas  does  not  hold  good  in  case  of  coke  oven  gas  or  those  gases  having  higher  flame 
temperature  in  their  explosive  mixture.  In  the  case  of  the  oven  gas,  for  instance,  one 
grain  of  sulphur  per  cubic  foot  should  be  the  limit  and  further  purification,  say,  to 
0.5  grains,  would  be  advisable.  All  sulphur  above  this  must  be  eliminated,  prefer- 
ably by  purification  with  oxide  of  iron. 


CHAPTER   XVIII 
HEAT:    TEMPERATURE,   RADIATION,   AND   CONDUCTION 


Flame  Temperature. — The  calorific  intensity  or  theoretical  flame  temperature 
of  a  substance,  says  Dowson,  is  the  temperature  to  which  the  products  of  combustion 
would  be  raised,  if  the  initial  temperature  were  0°  C.  or  32°  F.,  assuming  that  the 
combustion  is  complete,  that  no  excess  of  air  or  oxygen  is  used,  and  that  all  the  heat 
evolved  during  the  combustion  of  the  substance  is  taken  up  by  the  products.  The 
capacity  for  heat  absorption  of  a  gas  is  termed  its  specific  heat  and  is  therefore  a 
factor  in  flame  temperature  calculations. 

Specific  Heats  of  Gases. — The  specific  heat  of  a  gas  is  greater  when  the  gas  is 
heated  under  a  constant  pressure  (and  therefore  allowed  to  expand)  than  when  it 
is  heated  at  constant  volume. 

The  difference  between  the  specific  heat  of  a  gas  at  constant  pressure  and  at 
constant  volume  is 

1.98 

Centigrade  units, 


Molecular  weight  of  the  gas 

3.564 

or  -  Fahrenheit  units. 

Molecular  weight  of  the  gas 


MEAN  SPECIFIC  HEATS  OF  GASES  AT  CONSTANT  PRESSURE  BETWEEN  THE  ABSOLUTE 
ZERO  AND  THE  TEMPERATURE   t°  C. 

Gas.  Mean  Specific  Heat1  (C.  Units). 

a  o 

Carbon  monoxide 0.2326  +  0.0000214   X(£  +  273) 

Hydrogen 3.2500  +  0.0003000   X(Z  +  273) 

Methane 0.4070  +  0.0000376   X  (i  +  273) 

Nitrogen 0.2320  +  0.0000214   X(i  +  273) 

Oxygen 0.2036  +  0.0000188   X(i  +  273) 

Carbon  dioxide 0.1481+0.0000843   X(*  +  273) 

Water  vapor 0. 3619  +  0. 00001615X  (£  +  273) 

1  Based  on  Le  Chatelier's  values,  "Cours  de  Chimie  Industrielle." 

396 


HEAT:    TEMPERATURE,  RADIATION,  AND   CONDUCTION  397 

The  mean  specific  heat  of  a  gas  between  any  two  temperatures  ti°  and  t2°  C.  is 
found  as  follows: 

The  mean  specific  heat  between  absolute  zero  and  t°  C. 


where  the  values  of  a  and  b  are  taken  from  the  preceding  table. 

The  heat  required  to  raise  the  temperature  of  1  kilo  of  the  gas  from  the  absolute 
zero  to  ti°  C.  is 

a(ti  +273)  +b(ti  +273)2  calories. 

The  heat  required  to  raise  the  temperature  of  1  kilo  of  the  gas  from  the  absolute 
zero  to  £2°  C.  is 

a  (I*  i  +  273)  +  b(t2  +  273)  2  calories. 

The  heat  required  to  raise  the  temperature  of  1  kilo  of  the  gas  from  ti°  to  £2°  C.  is 
the  difference  between  these  two  quantities,  or 

a(tz  -<i)  +b(t2  -ti)  (Z2  +  *i  +546)  calories. 
The  mean  specific  heat  between  t\  and  t2  is  therefore 


Example.  —  The  mean  specific  heat  of  carbon  dioxide,  at  constant  pressure, 
between  0°'  and  1000°  C.  is 

0.1481  +  0.0000843  X  1546  =  0.2784. 

The  molecular  heat  of  gas  is  the  quantity  of  heat  required  to  raise  the  temper- 
ature of  22.32  cubic  meters  of  the  gas  (or  of  its  molecular  weight  in  kilos)  through 
1°C. 

Flame  Temperature.  —  The  resulting  flame  temperature  of  the  combustion  of 
any  substance  is  found  by  dividing  the  number  of  heat  units  evolved  by  the  products 
of  combustion  multiplied  by  their  respective  specific  heats.  Thus  for  producer  gas: 

Heat  units  evolved  per  cu.ft. 

=  Temperature. 


C02X0.0265  +  H2OX0.0173  +  NX  0.0192 

However,  since  in  practical  work  there  will  always  be  an  excess  of  air,  this  must 
be  taken  into  account  when  calculating  the  temperature,  thus: 

Heat  units  evolved  per  cu.ft. 
AirexcessX0.0191+CO2X0.0265  +  H2OX0.0173  +  Nx0.0192=    emPerature< 


398  GAS   PRODUCERS 

A  definite  distinction  should  at  all  times  be  made  between  theoretical  flame 
temperature  and  furnace  temperature,  the  former  being  only  relative  as  far  as  practical 
purposes  go.  In  the  latter  certain  distinct  conditions  arise,  which  must  be  carefully 
differentiated. 

For  instance,  the  increased  furnace  temperature  obtained  by  the  use  of  blast  or 
the  admission  of  either  or  both  elements  under  pressure,  is  due  to  the  relative  supply 
of  such  elements  to  the  ratio  of  loss  of  heat  by  the  furnace  through  radiation  and 
conduction. 

Although  these  losses  increase  almost  directly  with  temperature,  they  are  rela- 
tively slower  than  the  heat  generated,  and  if  the  combustion  be  accelerated,  it  is 
possible  to  generate  heat  within  certain  limits  more  rapidly  than  the  consequent  loss 
through  raidation  and  conduction  which  ensues.  Thus  it  becomes  a  ratio  of  the  rate 
of  combustion  to  the  rate  of  radiation,  and  the  acceleration  of  the  former  within 
certain  limits,  either  by  the  blast  of  both  elements  or  the  blast  of  one,  and  the 
consequent  kinetic  acceleration  of  the  other,  nets  a  certain  increment  of  temperature 
in  the  attendant  operation. 

Again,  where  combustion  of  gases  are  accelerated  by  pressure,  certain  benefits  are 
derived  through  mass  action  or  molecular  agitation,  that  is  to  say,  in  current  terms, 
a  more  thorough  "mix"  is  obtained. 

Also,  a  certain  advantage  is  gained  in  the  heat  balance  with  both  the  hot  and 
compressed  gas,  due  to  an  acceleration  of  mass  action  or  an  increased  molecular 
activity. 

In  connection  with  the  supply  of  gas  to  a  furnace  under  pressure,  as  has  just 
been  referred  to,  it  may  be  noted  from  experiments  that  in  a  furnace  where  the  elements 
admitted  under  atmospheric  pressure  gave  a  resultant  furnace  temperature  of  about 
1600°  F.,  their  admission  under  pressure  of  one-half  a  pound  increases  this  furnace 
temperature  to  2000°  F.,  while  the  increase  in  pressure  of  both  elements  to  2  Ibs., 
gave  a  corresponding  increase  of  temperature  to  2400°  F. 

One  authority  notes  a  temperature  as  high  as  3300  to  3400°  F.  attained  in 
a  furnace  where  both  gas  and  air  were  admitted  under  a  pressure  of  35  Ibs.  It  is 
likely  that  in  an  instance  of  this  kind  (the  value  of  the  gas  being  from  125  to  140 
B.T.U.  per  cu.ft.)  that  considerable  increase  in  temperature  was  obtained  by  the 
compression  or  condensation,  from  the  gas,  of  all  entrained  moisture,  this  same 
condition  being  observed  in  illuminating  gas  where  supplied  from  high  pressure 
transmissions. 

It  may  be  noticed  at  this  point  that  all  maximum  temperatures  must  necessarily 
be  obtained  at  the  expense  of  fuel  economy.  That  is  to  say,  where  maximum  furnace 
temperatures  are  reached,  a  percentage  of  CO  will  be  found  remaining  as  a  constituent 
of  the  products  of  combustion,  or  flue  gases. 

Theoretically  of  course  maximum  temperature  is  to  be  obtained  by  the  admission 
Of  the  theoretical  quota  of  air  for  oxidation,  but  in  practice  in  the  obtaining  of 
complete  combustion,  an  excess  of  air  must  be  admitted,  although  this  excess  is 
much  smaller  in  case  of  gases  than  that  necessary  for  the  complete  combustion  of 
solid  fuel. 

The  ratio  of  CO  appearing  in  flue  gases  (products  of  combustion)  with  maximum 
temperatures  has  been  noted  by  Professor  Breckenridge,  and  charted  in  his  report 


HEAT:    TEMPERATURE,  RADIATION,  AND   CONDUCTION  399 

to  the  United  States  Geological  Survey,  the  test  in  this  instance  being  of  course  in 
direct  firing  of  bituminous  coal. 

The  maximum  temperature,  it  will  therefore  be  noted,  will  be  obtained  under 
practical  working  conditions,  by  the  admission  of  about  the  theoretical  quantity  of 
air,  but  this  theoretical  quantity  of  air  will  be  insufficient  for  complete  combustion. 
Should  this  quantity  be  increased  to  the  necessary  excess  of  air,  the  combustion  will 
be  increased  and  the  temperature  (through  "  over- ventilation ")  decreased. 
Axiomatically  it  may  be  said  that  "maximum  temperatures  may  only  be  obtained 
at  the  expense  of  fuel  economy." 

This  discrepancy  is  of  course  reduced  to  the  minimum  where  the  elements  are 
.supplied  at  high  temperature,  for  the  reasons  already  noted. 

The  sensible  heat  of  a  gas  adds  to  the  flame  for  all  practical  purposes,  its  actual 
temperature  (Ti—T%)  above  atmospheric  and  to  the  effective  heat  of  the  furnace 
WxCxS,  the  latter  being  the  coefficient  of  heat  absorption  at  T2°  and  C  equalling 
number  of  calories  per  kg.  or  B.T.U.  per  pound  contained  at  TZ°. 

The  highest  temperature  that  can  theoretically  be  obtained  by  burning  a  gas 
in  air  is  the  temperature  that  will  be  reached  when  no  heat  is  lost  in  any  way,  all  the 
heat  developed  being  employed  to  heat  up  the  products  of  combustion  and  the  nitrogen 
accompanying  the  oxygen  drawn  from  the  air  for  this  combustion.  These  conditions 
are  of  course  never  obtained  in  practice,  but,  as  it  is  very  hard  to  measure  accurately 
the  losses  that  occur  in  practice,  the  maximum  theoretical  temperatures  are  used 
to  furnish  a  basis  for  comparisons  between  different  gases,  it  being  assumed  that 
the  relations  between  the  temperatures  actually  obtained  will  be  nearly  the  same  as 
those  existing  between  the  theoretical  temperatures,  although  the  absolute  temper- 
atures will  be  very  different  in  the  two  cases. 

This  maximum  theoretical  temperature  evidently  depends  upon  the  quantity 
of  heat  developed  by  the  combustion  of  a  unit  weight  of  gas  and  upon  the  quantity 
of  heat  required  to  raise  by  1°  the  temperature  of  the  products  resulting  from  the 
combustion  of  this  unit  weight,  and  the  quotient  obtained  by  dividing  the  quantity 
of  heat  produced  by  the  quantity  required  to  raise  the  temperature  of  the  products 
of  combustion  1°  will  give  the  highest  temperature  that  can  be  reached  by  burning 
the  given  gas.  The  quantity  of  heat  produced  is  given  by  the  calorific  value  of  the 
gas.  The  amount  of  heat  required  to  raise  the  temperature  of  the  products  of 
combustion  1°  can  be  calculated  by  multiplying  the  weight  of  each  product  that  is 
produced  by  its  specific  heat,  the  nitrogen  mixed  with  the  oxygen  in  the  air  and 
drawn  into  the  flame  with  it  being  included.  It  is  therefore  necessary  to  determine 
what  substances  are  produced  by  the  combustion  of  the  gas  and  the  weight  of  each 
of  these  substances  that  is  obtained  from  the  unit  weight  of  the  gases,  to  multiply 
the  determined  weight  of  each  substance  by  its  specific  heat,  and  to  add  together  the 
numbers  obtained  by  these  multiplications,  the  sum  forming  the  divisor  of  the  fraction. 

The  maximum  temperature  that  can  be  produced  by  burning  a  gas  in  air  can 
therefore  be  determined  by  dividing  the  calorific  value  of  the  gas  per  pound  by  the 
sum  of  the  numbers  obtained,  by  multiplying  the  weight  of  each  of  the  products  of 
combustion  produced  from  one  pound  of  gas  by  its  proper  specific  heat,  the  nitrogen 
mixed  in  the  air  with  the  oxygen  required  for  combustion  being  considered  as  one 
of  the  products  of  the  combustion. 


400  GAS   PRODUCERS 

To  illustrate  by  a  simple  example,  the  maximum  temperature  that  can  be 
produced  by  the  combustion  of  carbonic  oxide,  CO,  may  be  determined  as  follows: 

One  pound  of  CO  requires  for  its  combustion  to  carbonic  acid,  C02,  0.571  Ib.  of 
oxygen,  which  will  have  mixed  with  it  in  the  air  0.571X3.31  =  1.89  Ibs.  of  nitrogen,  N, 
and  the  products  of  the  combustion  of  1  Ib.  of  CO  will  therefore  be  1.571  Ibs.  of  C02 
and  1.89  Ibs.  of  N.  The  calorific  value  of  CO  is  4383  B.T.U.  per  pound,  the  specific 
heats  of  C02  and  N  are  respectively  0.217  and  0.244,  and  the  equation  of  the 
maximum  temperature  in  degrees  Fahrenheit  is 


T-  _        __  -  -  5465=  F. 

1.571X0.217  +  1.89X0.244     0.802 

The  theoretical  temperature  depends  upon  the  relation  between  the  quantity 
of  heat  developed  by  the  combustion  of  a  unit  weight  of  the  gas  and  the  amount 
of  heat  required  to  raise  by  1°  the  temperature  of  the  products  resulting  from  the 
combustion  of  this  unit  weight.  This  latter  amount  depends  upon  the  weight  of 
the  products  and  their  specific  heat  or  capacity  for  heat.  Therefore  a  gas  which 
yields  a  small  weight  of  products  of  combustion  with  low  specific  heats  will  produce 
a  high  flame  temperature,  even  though  its  heating  value  is  comparatively  low. 

Hydrogen  and  hydrocarbon  gases  containing  a  large  percentage  of  hydrogen 
yield  upon  combustion  large  weights  of  aqueous  vapor,  which  has  a  high  specific  heat, 
and  consequently,  in  spite  of  their  high  heating  value,  do  not  produce  as  high  flame 
temperatures  as  do  such  gases  as  carbonic  oxide,  which  have  a  lower  heating  value, 
but  give  smaller  weights  of  products,  having  a  lower  specific  heat  than  aqueous  vapor. 

Since,  when  the  gas  is  burned  in  air,  weight  of  the  nitrogen  mixed  with  the 
oxygen  in  the  air  is  added  to  that  of  the  products  of  combustion,  the  flame  tempera- 
ture is  lower  when  the  combustion  takes  place  in  air  than  it  is  for  combustion  in 
oxygen,  as  is  practically  illustrated  in  the  oxyhydrogen  flame. 

Influence  of  Kind  of  Gas.  —  R.  Casaubon,  in  a  discussion  on  the  "Temperature 
of  Flames"  (Gas  World,  February  22,  1908),  says  that  there  is  a  tendency  to  assume 
that  the  temperature  of  a  flame  can  be  measured  by  putting  a  solid  body  in  it,  and 
ascertaining  the  temperature  that  this  would  reach.  That  this  assumption  is  not 
justified  is  shown  by  the  fact  that  a  thermo-couple  shows  1600°  in  a  flame,  where, 
nevertheless,  a  fine  platinum  wire  will  melt.  But  in  the  experiment  cited,  the  conditions 
as  to  consumption  of  gas,  proportion  of  primary  air,  etc.,  are  very  imperfectly  detailed. 

In  an  incandescent  mantle  in  free  air  the  lighting  power  will  rise  from  2.3  to  21 
carcels  as  the  consumption  increases  from  1.695  to  6.912  cu.ft.  per  hour,  and  the 
proportion  of  primary  air  giving  the  highest  illuminating  power  in  each  case  rises 
from  4.20  to  4.93  times  the  volume  of  the  gas.  There  are  thus  two  variables,  the 
gas  consumption  and  the  proportion  of  primary  air.  If,  however,  we  enclose  the 
mantle  in  a  globe  with  only  a  small  opening  at  the  top  for  the  escape  of  the  products 
of  combustion,  the  consumption  increases  from  2.119  to  6.912  cu.ft.,  the  lighting 
power  from  0.67  to  23.9  carcels,  but  the  proportion  of  primary  air  only  from  5  to  5.03. 
Thus  we  have  practically  but  one  variable. 

This  indicates  that  the  velocity  of  the  flame  is  of  importance  in  determining 
the  temperature  attained  by  a  solid  body  immersed  therein,  and  also  of  the  flame 
temperature.  For  instance,  water  gas  has  a  theoretical  combustion  temperature 


HEAT:    TEMPERATURE,  RADIATION,  AND  CONDUCTION 


401 


of  2025°  C.,  the  volume  of  the  products  of  combustion  being  2.7  times  that  of  the 
original  gas,  while  coal  gas  has  a  theoretical  flame  temperature  1950°  C.,  with 
products  of  combustion  of  6.15  volumes.  In  the  case  of  the  coal  gas,  it  is  possible 
that  the  velocity  of  the  products  of  combustion  may  neutralize  any  advantage 
obtainable  through  the  higher  theoretical  velocity  of  the  water  gas.  While  this  does 
not  accord  with  Professor  Lewes 's  experiments,  an  explanation  may  be  that  he  used 
injector  burners  which  are  unsuited  for  coal  gas. 

Different  coal  gases  give  the  same  temperature  of  combustion;  but  the  volume 
of  the  products  of  combustion  increases  nearly  with  the  heating  value  of  the  gas. 
Therefore,  for  a  given  consumption  of  gas,  the  velocities  are  nearly  in  proportion  to 
their  heating  values.  This  is  in  accord  with  St.  Clair  Deville's  decision  that  the 
maximum  lighting  value  is  measured  by  the  heating  value  of  the  gas.  But  while 
this  is  true  for  cases  in  which  air  is  supplied  under  pressure,  it  is  by  no  means  so 
when  injectors  are  used.  Under  ordinary  pressures,  these  fail  to  bring  in  a  sufficient 
primary  air  supply  when  the  heating  value  of  the  gas  is  very  high.  Hence  it  may  be 
that  a  high  heating  value  is  useless  to  anybody  except  the  user  of  a  gas  engine. 
The  same  injector  mantle,  and  burner,  for  instance,  gave  practically  identical  candles 
per  foot  with  a  coal  gas  of  628  B.T.U.  and  a  water  gas  of  478  B.T.U. 

High  heating  powers,  as  in  the  case  of  methane,  which  requires  9.6  volumes  of  air, 
are  not  of  advantage  with  injector  burners  unless  the  pressures  are  suitably  high. 
Methane  alone  would  require  40  ins.  of  water,  but,  of  course,  methane  may  be  of 
great  value  as  a  means  of  bringing  the  heating  power  up  to  a  required  standard, 
whenever  it  becomes  cheap  enough,  just  as  benzol  brings  up  the  lighting  power. 

Melting-points. — Low  temperatures  may  be  determined  very  readily  by  noting 
whether  any  given  substance  of  known  ebullition  boils  when  subjected  to  the  given 
temperature  for  the  required  time.  The  following  tables  may  be  useful  in  this 
connection. 

BOILING-POINTS 

ALPHABETICALLY    ARRANGED 


Substance.  Deg.  F. 

Acetic  acid 245 

Air 311 

Alcohol,  grain 173 

Alcohol,  wood 150 

Ammonia —37 

Ammonia  aqua 140 

Benzene 176 

Bromine 137 

Cadmium 1580 

Carbon  disulphide 115 

Chlorine -40 

Chloroform • 140 

Coal  tar 325 

Cyanogen —6 

Ether 98 

Ethylene  chloride 184 

Fusel  oil 269 

Gasoline 175 

Glycerine 554 

Hydrocyanic  acid 79 

Hydrofluoric  acid 66 

Hydrogen  sulphide — 101 


Substance.  Deg.  F. 

Iodine 347 

Lead 1904 

Linseed  oil 600 

Mercury  chloride 572 

Mercury 675 

Naphtha 185 

Nitric  acid 248 

Oxygen -204 

Petroleum 316 

Phosphorus 554 

Potassium 1292 

Sal-ammoniac 257 

Salt,  saturated  solution 220 

Sodium 1310 

Sulphur 824 

Sulphuric  acid 620 

Turpentine  oil 315 

Varnish 600 

Water 212 

Water  in  vacuum 100 

Whale  oil 630 

Zinc .    1904 


402 


GAS   PRODUCERS 


BOILING-POINTS  AT  ATMOSPHERIC   PRESSURE 

ARRANGED    IN    THE    ORDER    OF    BOILING-POINTS 


Substance.  Deg.  F. 

Ether,  sulphuric 100 

Carbon  bisulphide 118 

Ammonia 140 

Chloroform 140 

Bromine 145 

Wood  spirit 150 

Alcohol 173 

Benzene 176 

Naphtha 186 

Water 212 

Milk 213 

Average  sea  water 213 .2 

Carbonate  of  soda,  saturated 220 . 3 

Acetate  of  soda,  saturated 225 .8 

Saturated  brine 226 

Nitrate  of  potash,  saturated 240 .6 


Substance.  De<?.  F. 

Nitric  acid 248 

Nitrate  of  soda,  saturated 250 

Carbonate  of  potash,  saturated 275 

Petroleum 306 

Oil  of  turpentine 315 

Petroleum,  rectified 316 

Coal  tar 325 

Acetate  of  potash,  saturated 336 

Phosphorus 554 

Sulphur 768 

Sulphuric  acid 590 

Linseed  oil 597 

Whale  oil 630 

Mercury 676 

Lead 1500 

Zinc  .  .                                                               .  1872 


MISCELLANEOUS  TEMPERATURE   DATA 
(From  Haswell  and  other  sources) 


Substance.  Deg.  F. 

Absolute  zero  of  temperature  —273°  C.  or .  .  —491 

Hydrogen  under  180  atm.  liquifies —205 

Nitrous  oxide  freezes — 150 

Boiling-point  of  liquid  ozone  at  atmospheric 

pressure — 119 

•Greatest  natural  cold —  56 

Liquid  ammonia  freezes —46 

Sulphuric  ether  freezes —46 

Sulphuric  ether  (sp.gr.  1.641)  freezes —45 

Nitric  acid  (sp.gr.  1.424)  freezes —45 

Proof  spirit  and  brandy  freezes --7 

'Snow  and  salt,  equal  parts 0 

.Spirits  of  turpentine  freezes +14 

;Strong  wines  freeze 20 

Human  blood  freezes 25 

Sea  water  freezes 28 

Vinegar  freezes 28 


Substance.  Deg.  F. 

Milk  freezes 30 

Olive  oil  freezes 36 

Vinous  fermentation 60-77 

Acetous  fermentation  begins 78 

Acetification  ends 88 

Heat  of  human  blood 98 

Highest  natural  temperature  in  Egypt 117 

Gutta-percha  softens 145 

Gutta-percha  vulcanizes 293 

Petroleum  boils 306 

Wood,  dried,  burns 340 

Mercury  volatilizes 680 

Ignition  of  bodies 750 

Heat  of  common  fire 790 

Combustion  of  bodies 800 

Charcoal  burns  .  .                                               .  800 


Higher  temperatures  can  be  tested  by  the  melting  points  of  other  substances 
as  specified  in  the  following  tables.  Various  authorities  do  not  agree  upon  the  exact 
figure,  but  substances  also  vary  and  the  method  is  more  convenient  than  accurate 
at  any  rate. 

MELTING-POINTS   OP   MISCELLANEOUS   SUBSTANCES 

ARRANGED    IN    THE    ORDER    OF   MELTING-POINTS 


Substance.  Deg.  F. 

Sulphurus  acid —  1 48 

Carbonic  acid — 107 

Bromine —     9.5 

Turpentine 14 

Hyponitric  acid 16 

Ice 32 

Nitroglycerin 45 

Pitch  or  butter 91 

Tallow 92 

Lard  .  .  95 


Substance.  Deg.  F. 

Phosphorus 112 

Acetic  acid 113 

Stearine 109-120 

Spermaceti 120 

Margaric  acid 131-140 

Beeswax,  rough , 142 

Beeswax,  bleached 154 

Stearic  acid 158 

Iodine 225 

Sulphur 239 


HEAT:    TEMPERATURE,  RADIATION,  AND  CONDUCTION  403 

MELTING-POINTS  OF  FUSIBLE  ALLOYS 


Ledd. 

Tin. 

Bismuth. 

Zinc. 

Cadmium. 

Mercury. 

Authority. 

Melting- 
points, 
Deg.  F. 

05 

95 

50 

250 

D'Arcet's  .... 

113 

25 

12  50 

50 

12.50 

Wood's  

149 

26 

12  78 

50 

10  40 

Lipowitz'  

149 

1 

1 

4 

1 

Quoted  by  Haswell  .... 

155 

25 

12 

50 

13 

Quoted  by  Haswell  .... 

150-160 

19  36 

19  97 

47  38 

13.29 

Guthrie's  "Cadmium"  .... 

160 

o 

1 

4 

1 

Wood's  

165 

3 

2 

5 

Stereotype  writing  pencils  .... 

199 

33  3 

33.3 

33.3 

Quoted  by  Haswell,  less  than  . 

200 

1 

1 

2 

Rose's  

200 

25 

25 

50 

D'Arcet's  

201 

1 

1 

4 

Quoted  by  Kent  and  Clark  . 

201 

5 

3 

8 

Quoted  by  Kent  and  Clark  .... 

202 

3 

5 

Quoted  by  Kent  and  Clark  

202 

31.25 

18.75 

50 

Newton's  

202 

28.10 

24.10 

50 

Rose's  

203 

3 

5 

8 

Quoted  by  Kent 

208 

1 

3 

5 

Quoted  by  Haswell  .  .  . 

210 

31 

19 

50 

Newton's,    quoted    by    Haswell, 

less  than  

212 

3 

2 

5 

Newton's  

212 

2 

3 

5 

Quoted  by  Haswell  .... 

212 

1 

4 

5 

Quoted  by  Kent  and  Haswell  .  . 

240 

1 

1 

1 

Clark  

254 

1 

2 

1 

Pewter's  solder  and  soap  molds 

? 

1 

1 

Quoted  by  Kent 

257 

1 

1 

Quoted  by  Kent  and  Haswell 

286 

2 

2 

1 

Quoted  by  Clark 

292 

4 

4 

1 

Quoted  by  Clark 

320 

2 

1 

Quoted  by  Kent  and  Haswell 

336 

3 

1 

Quoted  by  Kent  .  . 

392 

1 

1 

Quoted  by  Haswell  .  .  . 

399 

MELr 

Tin. 
2 

2 
2 
2 

MEL 

Tin. 
1 
1 
1 
1 
1 
1 

2' 
3 
4 
5 
6 

riNG-POINTS  OF  FUSIBLE  PLUGS.     (E 

Lead.                            Deg.  C.       Deg.  F.                          D 
2          Softens  at  185   =  365,            melts  at 
6                             189   =   372, 
7                  "         192  =  377i 
8                  "         202   =   395i 

TING-POINTS  OF  LEAD-TIN  ALLOYS. 

Lead.                                                                      Deg.  C 
25              .  .                                                           292 

[ASWELL) 

eg.  C.     Deg.  F. 
189   =   372 
195   =   383 
197   =  388 
209   =  408 

(KENT) 

.     Deg.  F. 
=   558 
=   541 
=   511 
=  482 
=   441 
=   370 
=  334 
=   340 
=  356 
=  365 
=  378 
=  381 

10 

.   283 

5            

266 

3 

250 

2          Cheap  solder  .... 

227 

1           Common  solder  

188 

1 

168 

1          Fine  solder  .  . 

171 

1            

180 

1 

185 

1 

192 

1 

.    194 

404 


GAS   PRODUCERS 
MELTING-POINTS   OF   SOLDERS.     (KENT)! 


Description. 

Tin. 

Lead. 

Copper. 

Brass. 

Nickel. 

Melting-points. 

Common  solder                 .          .  - 

j 

1 

188°  C      370°  F 

Fine  solder  

2 

1 

171°  C.,  340°  F. 

Cheap  solder  ....      

1 

2 

227°  C     441°  F 

( 

100 

5 

280-300°  C.,  536-572°  F. 

\ 

100 

5 

280-300°  C     536-612°  F 

Novel's  solder  for  aluminum  .  .  ] 

1000 

10-15 

350-450°  C     662-84  9°  F 

1000 

10-15 

350-450  C       662-842°  F 

For  the  determination  of  moderately  high  temperatures,  such  as  that  of  hot  blast 
supplied  to  furnaces,  use  is  often  made  of  metals  or  alloys  of  known  melting-points, 
and  when  two  such  substances  are  procurable  with  melting-points  differing  only  by 
a  few  degrees,  the  temperature  of  the  blast,  etc.,  can  be  readily  kept  within  that  range 
by  regulating  the  heating  apparatus,  so  that  one  test  piece  is  liquid  and  the  other 
solid.  By  employing  a  series  of  test  pieces  whose  melting-points  ascend  by  small  and 
fairly  regular  increments  a  tolerably  reliable  measurement  can  be  made  of  any 
temperature  within  the  range  of  our  test  pieces.  Prinsep's  alloys  furnish  us  with 
fairly  good  means  of  reading  temperatures  between  the  melting-point  of  silver  and 
that  of  platinum. 

MELTING-POINTS  OF   PRINSEP'S  ALLOYS 


Percentage  Composition  of  Alloy. 

Percentage  Composition  of  Alloy. 

Melting- 

Melting- 

point, 
Deg.  C. 

point, 
Deg.  C. 

Silver. 

Gold. 

Platinum. 

Silver. 

Gold. 

Platinum. 

100 

954 

60 

40 

1320 

80 

20 

975 

55 

45 

1350 

60 

40 

995 

50 

50 

1385 

40 

60 

1020 

45 

55 

1420 

20 

80 

1045 

40 

60 

14(10 

100 

1075 

35 

65 

1495 

95 

5 

1100 

30 

70 

1535 

90 

10 

1130 

25 

75 

1570 

• 

85 

15 

1160 

20 

80 

1610 

80 

20 

1190 

15 

85 

1650 

75 

25 

1220 

10 

90 

1690 

70 

30 

1255 

5 

95 

1730 

65 

35 

1285 

100 

1775 

The  values  of  the  higher  melting-points  are  probably  within  some  twenty  degrees  of  the  truth. 
Multiply  by  9  and  divide  by  5  to  get  Fahrenheit  degrees. 


MELTING-POINTS  OF   METALS 


Substance.  Deg.  F. 

Aluminum 1157 

Antimony 810  to  1150 

Bismuth 476  to    512 

Copper 1929  to  1996 

Lead 608  to    618 

Mercury 39 

Tin 442  to    451 

Zinc  .  .  680  to    779 


Substance. 

Yellow  brass 

Bronze 

Arsenic 

Cadmium 

Lithium 

Magnesium 

Potassium 136  to 

Sodium  .  .  194  to    208 


Deg.  F. 
1350 
1690 
365 
442 
356 
1200 
144 


HEAT:    TEMPERATURE,  RADIATION,  AND  CONDUCTION 


405 


MELTING-POINTS  OF  METALS— Continual 


Substance.  Ceg.  F. 

Iron,  gray 2030  to  2280 

Iron,  white 1190  to  2075 

Iron,  wrought 2700  to  2912 

Iron,  ferro-silicon 2040  to  2190 

Steel,  1.18-1.32.  C 2350  to  2450 

Steel,  hard 2570 

Steel,  mild 2687 

Steel,  ferro-manganese 2210  to  2255 

Steel,  ferro-tungsten 2240  to  2280 

Steel,  ferro-chrom 2180  to  2400 


Subetancas, 

Cobalt 

Nickel 

Manganese 


Des.  F. 

2000 

2732 

3400 

Gold,  pure 1913  to  2282 

Gold,  standard 2156 

Silver,  pure 1773  to  1873 

Platinum 3227 

Palladium 2732 

Rhodium 3650 

Iridium 3550 


MELTING-POINTS 

ARRANGED    ALPHABETICALLY 


Substance.  Deg.  F. 

Acetic  acid 113 

Almond  oil 15 

Aluminum 1112 

Aluminum  bronze 1796 

Antimony 810 

Arsenic 932 

Asphaltum 250 

Beeswax 145 

Bismuth 516 

Bonefat 70 

Brass 1869 

Bromine 19 

Bronze 1454 

Butterfat 90 

Cadmium 608 

Carnuba  wax 185 

Castor  oil 5 

Cerium 1292 

Chromium 3632 

Coal  tar 196 

Cobalt 2552 

Cocoa  butter 90 

Cocoanut  oil 75 

Cod-liver  oil 14 

Copper 1929 

Cottonseed  oil 54 

( 'otton  stearine 104 

Croton  oil 3 

Ferro-nickel 2660 

Germanium 1652 

Glass 1500-2300 

Gold 1913 

Ice 32 

Iodine 237 

Iridium 3632 

Iron,  gray 2228 

Iron,  white 2075 

Iron,  wrought 2900 

Lard 95 

Lead 622 

Linseed  oil 60 

Magneisum 932 

Manganese 2732 

Mercury —39 

Molybdenum 3992 


Substance.  De1?.  F. 

Neatsfoot  oil 40 

Nickel 2462 

Nitroglycerine 45 

Olive  oil 36 

Osmium 4892 

Palladium 2732 

Palm  oil 104 

Paraffine 130 

Phosphorus m 

Pitch 91 

Platinum 3227 

Porpoise  oil 3 

Potassium 136 

Potassium  sulphate 1830 

Rhodium 3432 

Rubidium 101 

Saltpeter 600 

Seal  oil 37 

Selenium 422 

Silicon 2372 

Silver 1742 

Sodium 205 

Spermaceti 120 

Sperm  oil — 13 

Stearic  acid 158 

Stearin 120 

Steel,  hard .' 2570 

Steel,  soft 2675 

Strontium 1112 

Sulphur 237 

Sulphurous  acid — 148 

Sunflower  oil 1 

Tallow 95 

Tellurium 851 

Thallium 561 

Tin 455 

Titanium 4532 

Tungsten 4712 

Turpentine 14 

Uranium 4352 

Wax 150 

Whale  oil 28 

Wool  fat 105 

Zinc 784 

Zirconium .  2372 


406  GAS   PRODUCERS 

Industrial  Operation    Temperatures. — The  following  tables  have  been    collected 

as  showing  what  temperatures  should  be  expected  in  various  kinds  of  furnaces  and 
operations. 

TEMPERATURES   IN   SOME   INDUSTRIAL   OPERATIONS 

Deg.  C.  Deg.  F. 

Gold — Standard  alloy,  pouring  into  molds 1180  2156 

Annealing  blanks  for  coinage,  furnace  chamber 890  1634 

Silver — Standard  alloy,  pouring  into  molds 980  1 796 

Steel — Bessemer  Process,  six-ton  converter: 

Bath  of  slag 1580  2876 

Metal  in  ladle 1640  2984 

"    ingot  mold 1580  2876 

Ingot  in  reheating  furnace 1200  2192 

' '     under  hammer 1080  1976 

Siemens  Open-hearth  Furnace: 

Producer  gas  near  gas  generator 720  1328 

entering  recuperator  chamber 400  752 

leaving  recuperator  shamber 1200  2192 

Air  issuing  from  recuperator  chamber 1000  1832 

Products  of  combustion  approaching  chimney 300  590 

End  of  melting  pig  charge 1420  2588 

Completion  of  conversion 1500  2732 

[beginning 1580  2876 

Pouring  steel  into  ladle  \      3-  0^1  A 

[  ending 1490  2714 

In  the  molds 1520  2768 

Siemens  Crucible  Furnace : 

Temperature  of  hearth  between  crucibles 1600  2912 

Blast  furnace  on  gray  Bessemer: 

Opening  in  front  of  tuyere 1930  3506 

Molten  metal  beginning  to  tap 1400  2552 

"    end  of  tap 1570  2858 

Siemens  Glass-melting  Furnace: 

Temperature  of  furnace 1400  2552 

Melted  glass 1310  2390 

Annealing  bottles 585  1085 

Furnace  for  hard  porcelain,  end  of  "  baking  " 1370  2498 

Hoffman  red-brick  kiln,  burning  temperature 1100  2012 


METAL  BATHS  FOR  TEMPERING.     (MOLESWORTH) 

Lead.  Tin. 

Turning  tools  for  metals 1 . 75  1 

Wood  tools,  taps  and  dies 2.5  1 

Hatchets,  chipping  chisels 4 . 75  1 

Springs 12  1 


HEAT:    TEMPERATURE,  RADIATION,  AND   CONDUCTION  407 

METALLURGICAL  WORKING  TEMPERATURES 

Deg.  C.  Deg.  F. 

Blast  furnace  at  tuyeres 2000  3632 

Blast  furnace  tapping 1600  2912 

Open  hearth  furnace  during  boil 1500  2732 

Medium  hard  steel  at  tapping 1600  2912 

Gas  leaving  producers 700  1292 

Gas  leaving  regenerators 1200  2192 

Air  leaving  regenerators 1100  2012 

Waste  gas  at  stack 300  572 

Medium  steel  ready  to  roll 1050  1922 

Glass  pots,  working 1050  1922 

Glass  pots,  refining 1325  2417 

Tanks  for  casting  glass 1325  2417 

Crucible  steel  furnace 1300  2372 

Cement  rotary  clinkering 1684  3000 

Shale  drain  tile  burning 871  1600 

Composition  earthenware 1015  1860 

Fire  clay  stoneware  burning 1610  2922 

Fire  clay  sewer  pipe,  hottest 1048  1920 

Shale  sewer  pipe,  hottest 1016  1862 

Fire-clay  paving  brick,  hottest 1048  1920 

Shale  paving  brick,  hottest 1000  1800 

Under  a  boiler,  hottest 1257  2295 

Ingot  being  rolled 1065  1950 

Heating  furnace 1150  2120 

Limestone  burning  (approx.) 1000  1832 

Distillation  of  gypsum : 300 

STEEL  WORKS  TEMPERATURES 

Deg.  C.  Deg.  F. 

Six-ton  Converter: 

Bath  of  slag 1580 

Metal  in  ladle 1640 

1 '    ingot  mold 1580 

Ingot  in  reheating  furnace 1200 

' '     under  hammer 1080 

Open-hearth  Furnace.     (Siemens  semi-mild  steel): 

Fuel  gas  near  generator 720  1328 

Fuel  gas  entering  into  bottom  of  regenerator 

chamber 400  752 

Fuel  gas  issuing  from  regenerator  chamber 1200  2192 

Air  issuing  from  regenerator  chamber 1000  1832 

Chimney  Gases. 

Furnace  in  perfect  condition 300  590 


408  GAS   PRODUCERS 

STEEL    WORKS    TEMPERATURES—  Continued 

Deg.  C.  Deg.  F. 

Open-hearth  Furnace: 

End  of  the  melting  of  pig  charge 1420                      2588 

Completion  of  conversion 1500                      2732 

Molten  Steel: 

In  the  ladle — commencement  of  casting 1580                      2876 

—end  of  casting 1490                      2714 

In  the  molds 1520                      2768 

For  very  mild  (soft)  steel  the  temperatures  are 
higher  by  50°  C. 

Siemens  Crucible  or  Pot  Furnace 1600                      2912 

Rotary  Puddling  Furnace 1340-1230             2444-2246 

Puddled  ball— end  of  operation 1330                      2426 

Blast  Furnace  (Gray-Bessemer  pig} : 

Opening  in  face  of  tuyere 1 930 

Molten  metal,  commencement  of  fusion 1400 

' '       end,  or  prior  to  tapping 1570 

Red-brick  Kiln  (Hoffmann's): 

Burning  temperature 1100                       2012 

Foundry  Irons  and  Steels: 

Melting  heat  of  white  cast  iron 1135                      2075 

"         "         gray  cast  iron 1220                      2228 

"         "         mild  steel 1475                       2687 

"         "         semi-mild  steel 1455                      2651 

hard  steel 1410                       2570 

Porcelain  Furnace  (for  hard  porcelain) : 

Heat  at  the  end  of  baking 1370                       2498 

Incandescent  Lamps: 

Heat  burning  normally 1800                      3272 

' '    when  pushed 2100                      3812 


SUITABLE  TEMPERATURES 

Deg.  F. 

Annealing  steel 900-1300 

malleable  iron  (furnace  iron) 1200-1400 

"     (cupola  iron) 1500-1700 

glass  (initial  temperature) 950 

Working  glass 1200-1475 

Melting  glass  (into  a  fluid) 2200 

Hardening  tool  steel 1200-1400 

Case  hardening  iron  and  soft  steel 1300-1500 

Core  ovens  in  foundries  .  350 


HEAT:    TEMPERATURE,  RADIATION,  AND  CONDUCTION 


409 


SUITABLE  TEMPERATURES— Confirmed 

Deg.  F. 

Drying  kilns  for  wood 300 

Baking  white  enamel                 j                                                   f  150 

' '       red  and  green  enamel  j>  bicycle  paint \  250 

"       black  enamel  300 

Vulcanizing  rubber 295 

Galvanizing 800 

Tinning 500 

Burning  pottery 2350 

brick 1800 

fire-brick 2450 

CANDY   MAKING;    BOILING-POINTS  FOR  SUGAR 

Variety  of  Candy.  Deg.  F.  Variety  of  Candy.  Deg.  F. 

Smooth 215-220  Hard  ball 246-250 

Thread 230  Soft  crack 290 

Blow 232-234  Hard  crack 310 

Feather 236-238  Hard  crack  limit 310 

Soft  ball 240  Caramel    320-400 

At  315°  sugar  begins  to  part  with  its  sweetness.  A  little  butter  added  when 
the  sugar  begins  to  boil  will  prevent  boiling  over.  Add  cream  of  tartar  at  240° 
unless  the  lower  boiling  points  are  wanted  without  crystallization. 

BAKING  TEMPERATURES 

Substance.  Deg.  F.                               Substance.                                                      Deg.  F. 

Bread 400  to  450  Drop  cakes 300  to  325 

Biscuit 400  to  450  Cookies 275  to  300 

Pastry 350  to  400  Angels'  food 250  to  300 

Eclairs 350  to  400  Wafers 175  to  200 

Cream  puffs 350  to  400  Kisses 175  to  200 

Lady  fingers 350  to  375  Macaroons 175  to  200 

Layer  cakes 300  to  350  Loaf  cake 175  to  200 

Annealing  and  Tempering  Heats. — This  data  applies  more  particularly  to  steel. 
The  temperatures  corresponding  to  different  colors  as  seen  in  a  furnace  are  now  known 
quite  accurately  through  the  investigations  of  Maunsel  White  and  F.  W.  Taylor, 
together  with  those  of  Professor  Henry  M.  Howe.  The  results  of  those  investigators 
have  entirely  discredited  the  old  and  generally  accepted  table  of  Pouillet,  which  is  still 
reproduced  in  most  text  books  and  manufacturers'  catalogues.  The  figures  of  Messrs. 
White  and  Taylor  and  Professor  Howe,  are  as  follows: 

COLOR   SCALE  OF   HIGH  TEMPERATURES 


White  and  Taylor. 


Howe. 


Color. 


Deg.  C.     !    Deg.  F. 


Color. 


Deg.  C. 


Deg.  F. 


Dark  red,  blood  red,  low  red 

Dark  cherry  red , 

Cherry,  full  red 

Light  cherry,  bright  cherry,  light  red 

Orange 

Light  orange 

Yellow 

Light  Yellow 

White. 


566 

635 

746 

843 

899 

941 

996 

1079 

1205 


1050 
1175 
1375 
1550 
1650 
1725 
1825 
1975 
2200 


Dull  red  .  .  . . 
Dull  red  .  .  . . 
Full  cherry  . 
Light  red  .  .  . 
Full  yellow  . 
Full  yellow  . 
Light  yellow. 
White. .  . 


550 

625 

700 

850 

950 

1000 

1050 

1150 


1022 
1157 
1292 
1562 
1742 
1832 
1922 
2102 


410 


GAS    PRODUCERS 


Deg.  C. 

261 
370 
500 

525 

700 

800 

900 
1000 
1100 
1200 
1300 
1400 
1500 
1600 


COLORS  ASSUMED  BY   INCANDESCENT  IRON   OR  STEEL.     (POUILLET) 

Deg.  F.  Characteristics  and  Colors. 

502  ^  Violet,  purple,  and  dull  blue.     Between  261°  C.  and  370°  C.,  it  passes  to  bright  blue, 

ggQ  \          sea  green,  and  then  disappears. 

qoo  /  Commences  to  be  covered  with  a  light  coating  of  oxide,  becomes  a  deal  more  im- 
pressible to  the  hammer,  can  be  twisted  with  ease. 

977     Becomes  nascent  red. 
1292     Somber  red. 
1472     Nascent  cherry. 
1657     Cherry. 
1832     Bright  cherry. 
2012     Dull  orange. 
2192     Bright  orange. 
2372     White. 
2552     Brilliant  white ;  welding  heat. 

Dazzling  white. 


The  above  colors  are  observed  in  the  furnace  and  can  best  be  observed  by  inserting 
a  1.5  in.  gas  pipe  to  within  a  yard  of  the  metal  and  looking  through  it.  Practical 
furnace  men  judge  temperatures  quite  closely  in  this  way. 


DRAWING  THE  TEMPER  OF  TOOLS.     (ROSE  AND  KENT) 


Very  pale  yellow,  430°  F.: 

Scrapers  for  brass. 

Steel-engraving  tools. 

Slight-turning  tools. 

Hammer  faces. 

Planer  tools  for  steel. 

Ivory-cutting  tools. 

Planer  tools  for  iron. 

Paper  cutters. 

Wood-engraving  tools. 

Bone-cutting  tools. 
Straw-yellow,  460°  F.: 

Milling  cutters. 

Wire-drawing  dies. 

Boring  cutters. 

Leather-cutting  dies. 

Screw-cutting  dies. 

Inserted  saw  teeth. 

Taps. 

Rock  drills. 

Chasers. 

Punches  and  dies. 

Penknives. 

Reamers. 

Half-round  bits. 
Brown  yellow,  500°  F.: 

Planing  and  molding  cutters. 

Stone-cutting  tools. 

Gauges. 


Brown  yellow,  500°  F.: 

Hand-plane  irons. 

Twist  drills. 

Flat  drills  for  brass. 

Wood-boring  cutters. 

Drifts. 

Coppersmith's  tools. 
Light  purple,  530°  F.: 

Edging  cutters. 

Augers. 

Dental  and  surgical  instruments. 
Dark  purple,  550°  F.: 

Cold  chisels  for  steel. 

Axes. 

Gimlets. 

Cold  chisels  for  cast-iron. 

Saws  for  bone  and  ivory. 

Needles. 

Firmer  chisels. 

Hack  saws. 

Framing  chisels. 

Cold  chisels  for  wrought  iron. 

Molding  and  planing  cutters. 

Circular  saws  for  metal. 

Screw-drivers. 

Springs. 

Dark  blue,  570°  F. 
Pale  blue,  610°  F. 
Blue-green,  630°  F.: 

Saws  for  wood. 


Above  list  is  arranged  in  the  order  of  the  color  scale  as  it  appears  on  bright  steel 
when  heated  in  the  air. 


HEAT:   TEMPERATURE,  RADIATION,  AND   CONDUCTION 


411 


TEMPER  COLORS  OF  STEEL.     (HASWELL) 


Deg.  C.  Deg.  F. 

221  430  Faint  yellow 

238  460  Straw  color. 

243  470  Dark  straw. 

277  530  Purple. 

289  550  Blue. 

293  560  Full  blue. 


Deg.  C. 
304 
316 
400 
474 
581 


Deg.  F. 
580 
600 
752 
884 
1077 


Polish  blue. 

Dark  blue. 

Bright  red  in  the  dark. 

Red  hot  in  twilight. 

Red,  visible  by  day. 


Quenching  should  take  place  when  the  above  colors  appear  on  the  brightened 
surface  of  steel. 


HEAT    RADIATION 

Stefan's  law  is  to  the  effect  that  the  amount  of  energy  radiated  is  proportional  to 
the  difference  between  the  fourth  powers  of  the  absolute  temperature  (C°  +  273)  of  the 
heated  body  and  that  of  its  surroundings.  Peclet  determined  that  assuming  such 
surroundings  to  be  at  0°  C.,  and  the  temperature  of  the  heated  body  at  100°  C.,  the 
following  amounts  of  radiation  in  c.s.-gram  calorie  units  (i.e.  the  number  of  gram 
calories  radiated  per  square  centimeter  of  surface  per  0°  C.)  per  100°  difference  in 
temperature,  to  be  according  to  the  following  table: 


Heat  Radiating  Surface. 

Polished  silver 0 .00054 

Silvered  paper 0 .00177 

Polished  brass 0 .00108 

Copper 0.00068 

Zinc  0.00102 

Tin 0.00090 

Polished  sheet  iron 0.00189 

Leaded  sheet  iron 0 .00273 

Ordinary  sheet  iron 0 .01164 


Heat  Radiating  Surface. 


C.G.S.  Calories, 
per  100°  C.  Diff. 

Russian  sheet  iron 0.01410 

New  cast  iron 0 .01332 

Oxidized  cast  iron 0.01410 

Glass 0.01222 

Paper 0.01583 

Lampblack 0 .01684 

Building  stone 0 .01500 

Plaster 0 .01500 

Wood?.  .  .  0.01500 


Stefan's  law  covering  other  ranges  of  temperature  would  also  use  these  figures  as 
a  basis;  or,  assuming  the  heat  radiated  from  100°  C.  to  0°  C.,  as  per  the  table,  to  represent 
a  difference  of  13.8X10  8,  then  between  the  temperatures  of  273  and  373  the  fourth 
powers  of  their  absolute  temperatures,  and  for  any  higher  numerical  difference  between 
the  fourth  powers  and  the  two  absolute  temperatures  concerned,  a  corresponding 
value  for  the  heat  radiated  could  be  calculated  by  interpolation.  To  save  calcula- 
tion Professor  Richards  has  deduced  from  Peclet 's  experiments  that  the  heat  radiated 
for  other  ranges  of  radiated  temperature  are  relatively  (assuming  the  figures  in  the 
above  table  to  represent  unity)  as  follows: 


Deg.  C.  above  0°. 
100 
150 
200 
300 
400 
500 


Multiplier. 

1.0 

2.0 

3.3 

7.0 

12.0 

18.3 


Deg.  C.  above  0°. 
600 
700 
800 
900 
1000 


Multiplier. 
26  0 
35.0 
45.3 
57.0 
70.0 


412 


GAS   PRODUCERS 


Through  these  calculations  one  is  enabled  to  determine  the  heat  lost  through 
radiation  and  to  add  such  loss  to  the  heat  transmitted  to  the  air  by  contact  or  conduction. 

As  has  been  before  stated  the  total  heat  lost  constitutes  the  sum  of  these  two. 
That  is  to  say,  radiation  plus  conduction,  and  which,  where  the  atmosphere  is  con- 
cerned, is  assumed  to  be  about  equally  divided. 

The  law  of  heat  transfer  through  conduction  or  contact  will  be  discussed  later, 
the  above  referring  merely  to  conduction  and  radiation. 

Taking  the  temperature  of  any  outer  solid  surface  carefully,  and  ascertaining  the 
temperature  of  the  surrounding  atmosphere  or  adjacent  bodies,  should  give  very 
nearly  the  total  loss  through  the  above  formula,  being  maintained  through  both  these 
sources. 

Good  heat  radiators  are  good  absorbers  to  an  equal  degree,  and  reflecting  power 
is  the  exact  inverse  of  radiating  power. 


RELATIVE   VALUE  OF   RADIATORS 


Substance. 


Relative  Radiating 
Value. 


Lampblack  or  soot 100 

Cast  iron,  polished 26 

Wrought  iron,  polished 23 

Steel,  polished 18 

Brass,  polished 7 

Copper,  polished 5 

Silver,  polished 3 


RADIATION   RATIOS.     (SUPLEE) 


Difference  in 
Temperature, 
Deg.  F. 

Ratio. 

Difference  in 
Temperature, 
Deg.  F. 

Ratio. 

Difference  in 
Temperature, 
Deg.  F. 

Ratio. 

10 

1.15 

160 

1.61 

310 

2.34 

20 

1.18 

170 

1.65 

320 

2.40 

30 

1.20 

180 

1.68 

330 

2.47 

40 

1.23 

190 

1.73 

340 

2.54 

50 

1.25 

200 

1.78 

350 

2.60 

60 

1.27 

210 

1.82 

360 

2.68 

70 

1.32 

220 

1.86 

370 

2.77 

80 

1.35 

230 

1.90 

380 

2.84 

90 

1.38 

240 

1.95 

390 

2.93 

100 

1.40 

250 

2.00 

400 

3.02 

110 

1.44 

260 

2.05 

410 

3.10 

120 

1.47 

270 

2.10 

420 

3.20 

130 

1.50 

280 

2.16 

430 

3.30 

140 

1.54 

290 

2.21 

440 

3.40 

150 

1.57 

300 

2.27 

450 

3.50 

HEAT:   TEMPERATURE,  RADIATION,  AND  CONDUCTION 


413 


COEFFICIENTS   OF   RADIATION.     (SUPLEE) 


Surface. 


B.T.U.  per  1°  F.  per 
Sq.ft.  per  Hour. 

Silver,  polished 0.02657 

Copper,  polished 0.03270 

Tin,  polished 0.04395 

Tinned  iron,  polished 0.08585 

Iron,  sheet,  polished 0.0920 

Iron,  ordinary 0 . 5662 

Glass 0.5948 

Cast  iron,  new 0 . 6480 

Cast  iron,  rusted 0 . 6868 

Sawdust 0. 7215 

Sand,  fine 0.7400 

Water 1 .0853 

Oil.  .  1.4800 


RADIATION   LOSS  THROUGH  WALLS.     (SUPLEE) 

LOSS,    IN    BRITISH    THERMAL    UNITS,    PER    SQUARE    FOOT    PER    HOUR    FOR    1°    F.    DIFFERENCE 


Thickness  in  Inches. 

Brick. 

Stone. 

Thickness  in  Inches. 

Brick. 

Stone. 

4 

0.273 

0.330 

24 

0.129 

0.255 

8 

.223 

.312 

28 

.116 

.244 

12 

.188 

.295 

32 

.106 

.234 

16 

.163 

.280 

36 

.097 

.224 

20 

.144 

.267 

40 

.090 

.216 

CONDUCTION    OF   HEAT 

Conduction  of  heat  follows  very  nearly  the  analogy  of  conduction  of  electricity, 
and  the  conductivity  of  a  substance  for  one  is  nearly  identical  with  that  of  the  other. 

The  unit  of  heat  resistance  consists  of  a  cube,  1  cm.  square,  transmitting  1  gram 
calorie  of  heat  per  second  with  a  drop  of  temperature  potential  in  transmission  of  1° 
C.  For  example:  If  a  sheet  of  copper  with  a  thermal  conductivity  of  0.92  units,  the 
amount  of  heat  passing  per  hour  through  a  sheet  1  cm.  square  by  1  mm.  thick  with 
a  constant  difference  of  1°  C.  between  the  two  sides,  would  be  as  follows: 


0.92  X 


X  3600  =  331,  200,000  gram  calories 

=  331,000  kg.  cal.  (Richard's  metallurgical  calculations). 


The  factor  0.92  merely  indicates  that  this  is  the  fraction  of  unit  resistance 
possessed  by  copper,  hence  a  sheet  one-tenth  as  thick  and  ten  thousand  times  the  area, 
would  have,  during  one  hour,  the  heat  passing  through  1°  C.,  as  above. 

The  standard  unit  known  as  the  c.g.s.-gram  calorie  unit,  has  been  tabulated  by 
Professor  Richards  of  Lehigh  University,  as  follows: 


414  GAS   PRODUCERS 

HEAT  CONDUCTIVITY 

Substances.  C.g.s.  calorie,  per  1°  C.  Diff. 

Ice  * 0.00500 

Snow  0.00050 

Glass  (10-15°) 0.00150 

Water 0.00120 

Quartz  sand  (18-98°) 0.00060 

Carborundum  sand  (18-98°) 0.00050 

Silicate  enamel  (20-98°)  t 0.00040 

Fire-brick,  dust  (20-98°) 0.00028 

Retort  graphite  dust  (20-100°)  J 0.00040 

Lime  (20-98°)  § 0.00029 

Magnesia  brick,  dust  (20-100°) 0.00050 

Magnesia  calcined,  Grecian,  granular  (20-100°) 0.00045 

Magnesia  calcined,  Styrian,  granular  (20-100°) 0.00034 

Magnesia  calcined,  light,  porous  (20-100°) 0.00016 

Infusorial  earth  (Kieselguhr)  (17-98°) 0.00013 

Infusorial  earth  (0-650°) 0.00038 

Clinker,  in  small  grains  (0-700°) 0.00110 

Coarse  ordinary  brick  dust  (0-100°)  0.00039 

Chalk  (0-100°) 0.00028 

Wood  ashes  (0-100°) 0.00017 

Powdered  charcoal  (0-100°) 0.00022 

Powdered  coke  (0-100°) 0.00044 

Gas  retort  carbon,  solid  (0-100°) 0.01477 

Cement  (0-700°) 0.00017 

Alumina  bricks  (0-700°) 0.00204 

Magnesia  bricks  (0-1300°) 0.00620 

Fire-bricks  (0-1300°) 0.00310 

Fire-bricks  (0-500°) 0.00140 

Marble,  white  (0°) 0.0017 

Pumice '.  . .  0.0006 

Plaster  of  Paris 0.0013 

Felt 0.000087 

Paper 0.00040 

Cotton 0.000040 

Wool 0.000035 

Slate 0.00081 

Lava 0.00008 

Pumice 0.00060 

Cork  0.00072 

Pine  wood 0.00047 

Oak  wood 0.00060 

Rubber 0.00047 

*  Useful  in  refrigerating  plants,  where  pipes  become  coated  with  ice,  as  in  Gayley's  method 
t)f  drying  blast. 

•(•  Explains  the  small  conductance  of  enameled  iron  ware. 

|  Datum  useful  where  articles  are  packed  in  this  poorly  conducting  material. 

§  Datum  would  be  highly  useful  for  oxyhydrogen  platinum  furnaces  if  it  were  only  known  at 
liigh  temperatures. 


HEAT:    TEMPERATURE,  RADIATION,  AND  CONDUCTION  415 

Referring  to  the  analogy  between  heat  and  electricity,  as  Prof.  Richards 
suggests,  if  we  call  R  the  thermal  specific  resistance  in  c.g.s.-units  in  the  material 
of  a  wall  or  partition  having  a  thickness  of  D  centimeters  and  an  area  of  S  square 

centimeters,  the  thermal  resistance  of  the  wall  or  partition  will  be   -     "—,  inversely 

o 

its  thermal  conductivity  will  be 

=  coefficient. 


RXd 

Another  factor,  however,  enters  into  the  equation,  viz.,  the  surface  resistance  (or 
reciprocal  conductivity)  of  the  surface  or  medium  surrounding,  abutting,  or  impinging 
upon  its  partition  and,  so  to  speak,  throwing  a  back  pressure  upon  it. 

Suppose  for  example,  two  bodies  of  water  of  different  temperatures  separated 
by  a  wall.  There  would  be  a  flow  of  heat  from  +  to  —  through  the  wall,  the  rapidity 
of  which  would  be  also  aided  or  retarded  by  the  capacity  of  heat  absorption  or  resis- 
tivity of  the  water  upon  the  minus  side,  which  we  may  term  R2,  the  transfer  from  the 
water  on  the  plus  side  to  the  wall  being  RI.  Hence,  we  have  water  to  wall,  resistivity 
of  wall,  wall  to  water,  or  three  elements,  that  is  to  say,  for  the  entire  equation  of 
thermal  resistance  we  would  have 

#1     RXd     Rz 

"S  ^ "IT"1"  S' 

the  thermal  conductance  being 

S 


(RXd)+R2 


=  coefficient. 


The  temperature  on  the  outside  of  a  partition  or  pipe  can  be  found  in  several 
ways,  either  by  laying  a  flat  bulb  thermometer  made  especially  for  the  purpose  against 
it,  or  to  put  against  it  the  junction  of  a  thermo-couple,  covering  the  couple  with  clay 
or  putty.  Another  way  is  to  take  small  pieces  of  metals  or  alloys  possessing  known 
melting  points,  and  observe  which  alloy  melts  against  the  hot  metal. 

As  a  matter  of  course  all  of  the  above  calculations  may  be  reversed  and  the 
temperature  on  the  inside  and  outside  surfaces  being  known,  the  heat  transmitted 
may  be  calculated,  or  if  the  temperature  of  these  two  surfaces  is  known  and  the  heat 
being  transmitted  is  measured  the  thermal  conductivity  of  the  partition  may  be 
calculated.  Further,  if  the  temperature  of  two  surfaces  is  known  and  also  its  thermal 
conductivity  and  also  the  thermal  conductivity  of  the  partition  and  the  temperature 
of  the  contingent  substances  on  either  side,  the  thermal  resistance  of  the  transfer  from 
either  of  the  contingents  to  the  surface  of  the  partition  may  be  ascertained. 

It  will  be  seen  from  the  above  that  the  total  heat  losses  is  the  sum  of  several  factors, 
the  total  of  which  is  much  greater  than  any  individual  one  composing  it.  For  more 
exact  information  in  this  matter  the  reader  is  referred  to  Prof.  Joseph  W.  Richards' 
published  works.  The  following  is  an  extract  from  his  "  Metallurgical  Calculations" 
(McGraw  Publishing  Co.),  p.  178. 


416  GAS   PRODUCERS 

Principles  of  Heat  Transfer.  —  "  We  have  already  had  to  speak  of  the  transfer  of 
heat  from  fluids  to  solids,  or  vice  versa,  and  in  one  specific  case  we  deduced  the  value 
2222  for  the  transfer  resistivity  from  hot  gases  to  the  surface  of  iron  pipe,  meaning 
thereby  that  for  each  degree  of  temperature  difference  between  the  gases  and  outside 
of  the  pipe  0.00045  gram  calorie  passed  per  second  through  each  square  centimeter  of 
contact  surface.  A  consideration  of  the  transfer  of  heat  through  such  contact  surfaces, 
from  gases  or  liquids  to  solids  and  vice  versa,  has  shown  that  the  transfer  resistivity 
varies  with  the  solid  and  with  the  fluid  concerned,  but  much  more  with  the  latter 
than  with  the  former,  and  is  very  largely  dependent  upon  the  circulation  of  the  fluid, 
that  is,  upon  the  rate  at  which  it  is  renewed,  and  therefore  upon  its  velocity.  The 
conductivity  or  resistivity  of  such  a  transfer  must,  therefore,  contain  a  term  which 
includes  the  velocity  of  the  fluid.  Various  tests  by  physicists  have  shown  the  specific 
conductance  (or  conductivity  of  transfer)  to  vary  approximately  as  the  square  root  of 
the  velocity  of  the  fluid. 

"  From  metal  to  air  or  similar  gases,  the  mean  velocity  of  flow  being  expressed  in 
centimeters  per  second,  and  the  other  units  being  square  centimeters  and  gram  calories, 
the  transfer  resistivity  is  approximately 

_  36,000 
H  — 


and  the  transfer  conductivity  of  the  contact 

k  =  0.000028  (2  +  Vv). 

From  hot  water  to  metal  the  relations  are  similar,  but  the  conductivity  is  much  better. 
Experiments  show  values  as  follows: 

k  =  0.000028  (300  +  180  Vv)  , 
36,000 


R  = 


300  +  180VV 


"Illustration  1. — In  the  preceding  case  of  the  iron  pipe,  calculate  the  difference 
of  temperature  of  the  water  in  the  pipe  and  the  inner  surface  of  the  pipe,  assuming 
the  water  to  be  passing  through  at  a  velocity  of  4  cm.  per  second.  Using  the  above 
given  formula,  the  heat  transfer  per  1°  difference  would  be: 

0.000028  (300  +  ISO'S/4)  =0.0185  calories, 

and  the  difference  to  transfer  0.084  calories  per  second  will  be 

0.084 


0.0185 


=  4°.6. 


The  inner  surface  of  the  iron  pipe  will  be,  therefore,  continuously  4°.6  higher  than  the 
water,  and,  therefore,  at  14°.6;  the  outer  surface  will  be  continuously  0°.3  higher,  or 
practically  at  15°. 


HEAT:    TEMPERATURE,  RADIATION,  AND  CONDUCTION  417 

'•'  Illustration  2.  —  A  steam  radiator,  surface  at  about  100°  C.,  caused  a  current  of 
hot  air  to  rise  having  a  velocity  of  about  10  cm.  per  second,  which  was  insufficient  to 
keep  the  room  warm.  An  electric  fan  was  set  to  blow  air  against  the  radiator,  which 
it  did  with  a  velocity  of  about  300  cm.  per  second,  and  keeping  the  room  comfortably 
warm.  What  were  the  relative  quantities  of  heat  taken  from  the  radiator  in  the 
two  cases? 

The  relative  thermal  conductivities  of  transfer  were 


or     5:16, 

Showing  over  three  times  as  much  heat  taken  away  per  unit  of  time  in  the  second 
instance. 

"  This  illustration  proves  the  great  efficiency  which  the  metallurgist  may  attain  in 
air  cooling  of  exposed  surfaces,  by  blowing  the  air  against  them  instead  of  merely 
allowing  it  to  be  drawn  away  by  its  ascensive  force." 

Conduction  through  Walls.  —  The  transfer  of  heat  through  walls  of  various  materials 
may  be  expressed  by  the  following  equation: 


where  g  =  B.T.U.  transmitted  per  square  foot  per  hour. 
TI  —T2  =  Difference  in  temperature  between  the  two  surfaces. 
R  =  Resistance  offered  by  the  wall. 

R  is  composed  of  two  elements:  the  resistance  of  the  material  itself,  and  the 
resistances  of  the  surfaces  of  the  wall.  The  resistance  of  the  material  is  proportional 
to  the  thickness  (x)  and  another  quantity  (r)  depending  only  on  the  material. 

The  following  are  the  values  of  rX  where  X=l  in.  for  several  materials: 

rX 

Copper 0.0018 

Aluminum 0.0023 

Iron 0.0043 

Brick 0.1500 

The  resistance  of  one  surface  is  represented  by  E, 

E  =  °'5 


A  and  B  depend  on  the  kind  of  surface  and  on  the  nature  of  the  medium  resting 
against  it,  as  given  below: 

Surface.  A  B 

Gas  on  polished  metals 0.90  0.0028 

Gas  on  rough  metallic  and  other  surfaces 1 .59  0.00 

Liquids 8.8  0.058 


418  GAS   PRODUCERS 

In  boiler  work  where  the  material  and  its  surface  are  constant,  the  formula 


q=     ~A  --  ' 

where  A  =  160  to  200,  gives  very  good  results. 

The  great  influence  "of  the  kind  of  surfaces  and  the  medium  pressing  on  it,  is 
evident  from  the  following  table: 

B.T.U.  TRANSMITTED   PER  HOUR  PER  SQUARE  FOOT  WHERE  THE  DIFFERENTIAL 
TEMPERATURE   IS  ONE   DEGREE   FOR  EACH   INCH   OF  THICKNESS 

Steam  to  water,  copper  ........................  ..........  1000 

"       wrought  iron  ............................  200 

"       cast  iron  ............................  •  ____  100 

Steam  to  air,  polished  copper  .............................  0.0327 

"    polished  tin  .......................  .........  0.044 

"          "    polished  sheet  iron  .....................  .....  0.092 

'  '    ordinary  sheet  iron  ..........................  0  .  5662 

"          "    ordinary  cast  iron  ...........................  0  .  648 

'  '    ordinary  steam  pipe  .........................  0  .  64 

Air  to  air  (building  walls),  marble  .........................  25. 

"       "    limestone  ....................................  15. 

"    red  brick  .....................................  5. 

"    fire-brick  .....................................  12. 

"    pine  .........................................  2.2 

Gases  and  liquids  transmit  heat  very  slowly  when  at  rest.  This  fact,  together 
with  numberless  repetition  of  the  surface  resistance,  is  probably  the  cause  of  the  value 
of  some  porous  substances  as  heat  insulators. 

The  following  table  gives  the  relative  quantities  of  heat  transmitted  by  several 
heat  insulators: 

Asbestos  ........................  8.17 

Slag  wool  .......................  2.17 

Bituminous  ashes  ................  3.5 

Carbonate  of  magnesia  ...........  2  .  28 

This  would  seem  to  indicate  that  asbestos  is  really  one  of  the  poorest  insulators 
and  should  be  used  sparingly  and  only  to  hold  the  other  material  in  place. 

However,  consensus  of  opinion  seems  to  be  that  the  asbestos  heat  insulating 
lining  supplies  greater  economy  than  the  dead  air-space  of  gas-ranges,  although  this 
would  probably  not  be  true  theoretically.  In  practice  the  dead  air-space  is  impossible 
of  realization  and  the  practical  loss  of  radiant  heat  is  greater;  moreover,  the  asbestos- 
lined  oven  seems  to  have  its  heat  more  evenly  distributed.  The  following  table,  com- 
piled by  Prof.  C.  L.  Norton,  shows  the  protection  afforded  by  insulating  linings: 


HEAT:   TEMPERATURE,  RADIATION,  AND  CONDUCTION  419 

A  steam-pipe  heated  to  385°  F.  shows  an  outside  temperature  of 

356°  covered  with  asbestos-paper  ^  in.  thick. 
329°  & 

302°  "  "  A 

266°  "  "  I         -' 

J.  C.  Bertsch  is  authority  for  the  statement  that  the  transmission  of  heat  per  square 
foot  of  surface  per  minute  through  a  dead  air-space  1  in.  in  thickness  is  8  B.T.U.,  while 
that  of  asbestos-paper  1  in.  thick  is  3£  B.T.U.  He  moreover  states  that  the  dead  air- 
space, properly  speaking,  does  not  exist  in  the  oven  of  the  modern  gas-range,  it  being 
impossible  to  join  the  metal  sheets  so  closely  as  to  prevent  circulation;  under  these 
conditions  air  has  little  or  no  value  as  an  insulator.  Therefore  asbestos-boards 
j"g  to  £  in.  in  thickness  are  the  more  effective  and  economical  and  moreover  tend  to  form 
a  dead  air-space  with  the  outside  metal  sheet. 

Heat  Absorption  by  Water. — Siebel  notes  that  the  rate  of  emission  of  heat  from 
steam  pipes  in  terms  of  water  amounts  in  round  numbers  to  from  150  to  250  times  the 
rate  in  air,  according  as  the  pipes  are  in  vertical  or  horizontal  positions. 

Experiments  of  the  writer  go  to  show  an  average  of  300  times  the  rate  of  heat  losa 
by  hot  water  in  pipes  when  surrounded  by  water  as  when  surrounded  by  air. 

Water  Absorption. — G.  B.  Nicholl  experimented  with  an  ordinary  surface  condenser 
brass  tube  f  in.  in  diameter,  No.  18  wire  gauge  in  thickness,  encased  in  a  3f  in.  iron 
pipe.  Steam  of  32£  Ibs.  total  pressure  per  square  inch  occupied  the  inter-space  while 
cold  water  at  58°  F.  initial  temperature  was  run  through  the  brass  tube.  Three 
experiments  were  made  with  the  tubes  in  a  vertical  position,  and  three  in  a  horizontal 
position. 


Experiments  to  Determine. 

Vertical  Postion. 

Horizontal. 

I. 

II. 

III. 

IV. 

V. 

VI. 

Velocity  of  water  through  tube  in  feet  per  minute  .  .  . 

.81 
.335 
346 

278 
.436 
449 

390 
.457 
466 

78 
.480 
479 

307 
.603 
621 

415 

.609 
699 

Steam  condensed  in  Ibs.  per  sq.ft.  of  surfaces  per  hour  for 
1°  F   difference  in  temperature 

Heat  absorbed  by  the  water  per  sq.ft.  per  hour  per  1°  F. 
difference  of  temperature  in  B.T.U  

HEATING  AND  EVAPORATING  WATER  BY  STEAM  THROUGH  METALS 


Metal  Surface. 

Per  Square  Foot  per  1°  F.  Difference  of  Temperature. 

Steam  Condensed. 

Heat  Transmitted. 

Heating, 
Pounds. 

Evaporating 
Pounds. 

Heating, 
B.T.U. 

Evaporating, 
B.T.U. 

Copper  plate    .  .                    

0.248 
0.291 
0.077 

0.483 
1.070 
0.105 

276 
312 

82 

534 
1038 
100 

Copper  pipe                

Cast-iron  boiler           

420 


GAS   PRODUCERS 


STEAM   CONDENSED   IN   BARE   CAST-IRON   PIPES   IN   AIR   AND   HEAT   EMITTED   AT 

ORDINARY  TEMPERATURES.     (SIEBEL) 


Steam. 

Difference  or 

Steam  Condensed  per  Square  Foot 
per  Hour. 

Heat  Emitted  per  Square  Foot 
per  Hour. 

Total 
Pressure 
per  Sq.in., 
Pounds. 

Temperature 
Deg.  F. 

Temperature 
of  Steam  above 
62°  F. 

Total, 
Pounds. 

Per  1°  of  Differ- 
ence, Pounds. 

Total, 
B.T.U. 

Per  1°  F. 
of  Difference, 
B.T.U. 

14.7 

212 

150 

0.29 

0.00193 

276 

1.84 

18 

222 

160 

0.346 

0.00216 

329 

2.05 

21.5 

232 

170 

0.405 

0.00238 

284 

2.26 

26 

242 

180 

0.47 

0.00261 

446 

2.48 

31 

252 

190 

0.54 

0.00284 

513 

2.70 

36.5 

262 

200 

0.607 

0.00303 

577 

2.89 

43 

272 

210 

0.682 

0.00325 

648 

3.08 

51 

282 

220 

0.75 

0.00345 

722 

3.28 

Heat  Absorption  by  Air. — Concerning  the  transmission  of  heat  through  metal 
plates  from  air  or  other  dry  gas  to  water,  Siebel  says  as  follows : 

The  rate  of  transmission  of  convected  heat  is  probably  from  two  to  five  units  of 
heat  per  hour  per  square  foot  of  surface  per  1°  F.  of  difference  of  temperature. 

In  a  locomotive  fire  box  where  radiant  heat  co-operated  with  convected  heat  the 
following  results  have  been  obtained  in  generating  steam  of  80  Ibs.  pressure  per  square 
inch.  The  temperature  of  the  fire  is  taken  at  2000°  F. 


Pounds  Water  Evaporated  per 
square  foot  per  hour. 

B.T.U.  Transmitted  per  square 
foot  per  hour  per  1°  F. 
Difference  of  Temperature. 

Burning  coke  75  Ibs.  per  sq.ft.  of  grate  

25  5 

14  5 

Burning  briquettes  74*  Ibs.  per  sq.ft.  of  grate  .  . 

35 

20 

There  are  in  practice  little  or  no  differences  between  iron,  copper,  and  lead  in 
evaporative  activity,  when  the  surfaces  are  dimmed  or  coated,  as  under  ordinary 
conditions. 

In  Motion. — The  comparative  rate  of  emission  of  heat  from  water  tubes  in  air  and 
in  water  at  rest  and  in  motion  has  also  been  investigated.  It  appears  that  the  rate  of 
emission  from  water  tubes  in  water  was  about  twenty  times  the  rate  in  air.  Craddock 
proved  it  experimentally  to  be  twenty-five  times.  When  the  water  tube  was  moved 
through  the  air  at  a  speed  of  59  ft.  per  second,  it  was  cooled  in  one-twelfth  of  the  time 
occupied  in  still  air.  In  water  moved  at  a  speed  of  3  ft.  per  second,  the  water  in  the 
tube  was  cooled  in  half  the  time. 

From  some  recent  observations  made  in  Germany,  the  following  data  giving  the 
transmission  of  heat  through  metal  partitions  per  hour  per  square  foot  and  per  1°  F. 
difference  between  each  side,  was: 


HEAT:   TEMPERATURE,  RADIATION,  AND  CONDUCTION  421 

Smoke  or  air  through  metal  to  air 1 . 20  to  1 . 70  B.T.U. 

Steam  through  metal  to  air 2.40  to  3.40       " 

Water  through  metal  to  air  or  reverse 2. 15  to  3. 15      " 

Steam  through  metal  to  water 200        to  240            " 

Steam  through  metal  to  boiling  water 1000 

Water  through  metal  to  water 72 

The  heat  radiated  from  a  coal  or  a  coke  fire  is  estimated  to  be  about  one-half  of 
the  whole  heat  generated.  It  increases  almost  as  fast  as  the  rate  of  combustion  of 
the  fuel  per  hour  per  square  foot. 

CONVECTION  O7    HEAT   FROM  AN   EXTERNAL   SURFACE 

Air C=.2849*1-233 

Hydrogen C=  .9827/1-233 

Carbonic  acid C=  .2759Z1-233 

Olefiant  gas C=  .3817<L233 

C  =  quantity  of  heat  in  B.T.U.  conveyed  away  from  a  solid  body  by  a  gas 
external  to  it,  per  square  foot  of  surface  per  hour  under  one  atmosphere 
of  pressure. 
t  =  excess  temperature  of  surface  in  degrees  F. 

Summar;/. — From  the  foregoing  experimental  data  and  from  other  experimental 
sources  it  appears  that  the  transference  of  heat  from  steam  through  iron  pipes  to  air 
increases  considerably  with  the  pressure  of  the  steam  which  may  be  explained  by  the 
greater  velocity  and  force  with  which  the  molecules  of  the  steam  impinge  on  the  walls 
of  the  pipe  at  the  higher  pressure  and  the  correspondingly  higher  temperature  combined 
therewith. 

Accordingly  the  coefficient  n  or  the  transfer  of  heat  from  steam  to  air,  varies  from 
1.8  to  3.5  B.T.U.  according  to  pressure  per  hour  for  every  square  foot  of  pipe  surface 
and  for  every  Fahrenheit  degree  difference  on  each  side  of  pipe.  For  average  conditions 
about  three  units  are  frequently  adopted.  The  transfer  of  heat  from  steam  to  water 
is  variously  estimated  at  from  200  to  240  B.T.U.  for  iron  pipe  (280  B.T.U.  for  copper 
pipe). 

The  transference  of  heat  or  of  refrigeration  from  water  to  water  or  to  brine  and 
water  or  the  reverse,  brine  to  water,  or  brine  through  iron  pipe,  is  about  the  same,  and 
is  generally  assumed  to  amount  to  80  B.T.U.  per  hour  in  counter-current  arrange- 
ments or  in  a  Baudelot  cooler. 

The  transference  of  heat  from  brine  or  water  through  iron  pipe  to  air  or  the 
reverse  is  rated  at  2^  B.T.U.  in  still  air,  but  if  the  air  is  moved  it  may  be  increased  to 
4  and  5  B.T.U.  per  hour  and  per  square  foot  surface  per  1°  F.  difference. 

The  transfer  of  heat  from  ammonia,  such  as  is  circulated  in  refrigerator  coils 
through  such  coils  to  air,  is  roundly  estimated  at  10  B.T.U.  per  hour,  and  from  ammonia 
to  brine  and  water,  as  in  condenser  coils,  it  may  be  taken  at  30  B.T.U.;  in  round 
numbers  for  1°  F.  difference  in  temperature  and  per  square  foot  of  surface.* 

*  For   further  information  see  Siebel's    "Compendium  of  Mechanical  Refrigeration,"  Nickerson, 
Collins  Co..  Chicago,  publishers. 


422 


GAS   PRODUCERS 


COOLING   OF   WATER   IN   PIPES   EXPOSED   TO   AIR.     (SIEBEL) 


Two-inch  Wrought-iron  Pipes. 

Four-inch  Cast-iron  Pipes. 

I. 

II. 

III. 

IV. 

I. 

II. 

III. 

IV. 

Tempera  tuie  of  the  atmosphere  in 
degrees  F  .  .  .  

53 

103.7 
233.7 
2.25 

53 

49.4 
104.4 
2.11 

52.5 

25.4 
46.45 
1.83 

52 

14.3 
19.7 
1.39 

GO 

62.3 
99.5 
1.59 

GO 

48.5 
69.9 
1.53 

60 

33.9 
49.5 
1.46 

59 

27.3 
38.2 
1.4 

Average  difference  of  tempera- 
tures of  the  water  and  the  air  in 
degrees  F.  .  .  

Total  heat  emitted  per  sq.ft.  per 
hour  in  B.T.U.  .  .  . 

Heat  emitted  per  1°  F.  difference 
of  temperature,  B.T.U  

RADIATION   LOSS  IN   IRON   PIPES.     (FROM  SUPLEE) 


Units  of  Heat  (B.T.U)  Emitted,  per  Square  Foot  per  Hour.     Temperature  of  Air  =  70°  F. 

Mean  Tempera- 
ture of  Pipes, 
Deg.  F. 

By  Convection. 

By  Radiation 

A  I,-.**** 

By  Convection  and  Radiation 
Combined. 

Air  Still. 

Air  Moving. 

Alone. 

Air  Still. 

Air  Moving. 

80 

5.04 

8.40 

7.43 

12.47 

15.83 

90 

11.84 

19.73 

15.31 

27.15 

35.04 

100 

19.53 

32.55 

23.47 

43.00 

56  02 

110 

27.86 

46.43 

31.93 

57.79 

78.36 

120 

36.66 

61.10 

40.82 

77.48 

101.92 

130 

45.90 

76.50 

50.00 

95.90 

126.50 

140 

55.51 

92.52 

59.63 

115.14 

152.15 

150 

65.45 

109  .  18 

69.69 

135.14 

178.87 

160 

75.68 

126  .  13 

80.19 

155.87 

206.32 

170 

86.18 

143.30 

91.12 

177.30 

234.42 

180 

96.93 

161.55 

102.50 

199.43 

264.05 

190 

107.90 

179.83 

114.45 

222.35 

294.28 

200 

119.13 

198.55 

127.00 

246  .  13 

325.55 

210 

130.49 

217.48 

139.96 

270.49 

357.48 

220 

142.20 

237.00 

155.27 

297.47 

392.27 

230 

153.95 

256.58 

169.56 

323  .  51 

426  .  14 

240 

165.90 

279.83 

184.58 

350.48 

464.41 

250 

178.00 

296.66 

200.18 

378.18 

496.84 

260 

189.90 

316.50 

214.36 

404.26 

530.86 

270 

202.70 

337.83 

233.42 

436.12 

571.25 

280 

215.30 

358.85 

251.21 

466.51 

610.06 

290 

228.55 

380.91 

267.73 

496.28 

648.64 

300 

240.85 

401.41 

279.12 

519.97 

680.53 

HEAT:    TEMPERATURE,  RADIATION,   AND   CONDUCTION 


423 


COEFFICIENTS  FOR   THE  TRANSMISSION   OF   HEAT. 
Transmission   per  square  foot,   in   B.T.U.   per  twenty-four  hours,   per  lc 
perature  of  the  air  inside  and  outside  (adopted  in  Germany). 

BRICK  MASONRY 


(SIEBEL) 
F.  difference  of  tem- 


15" 
6.50 
5.00 
7.50 
6.25 


20" 
5.25 
4.25 
6.00 
5.00 


Thickness  of  wall 12" 

Sandstone 11.0 

Limestone 13 .0 


16" 

9.60 

11.50 


32" 
6.35 

7.90 


Thickness  of  wall 5"  10" 

Outside  walls 12.00       8.50 

Outside  walls  \\  ith  air  spaces 6.10 

Outside  walls  with  stone  facing 9  .50 

Inside  walls 11 .00       8 .00 

STONE  MASONRY 
20"         24"        28" 
8.50       7.65       6.95 
10.30       9.35       8.50 
WOODWORK 

B.T.U. 

Ceiling  made  of  joists 2.5 

Solid  ceiling  with  planks 4.0 

Floor  of  rafters 2.0 

Vaulting  with  planks 3.0 

Solid  stone  floor 5.0 

Solid  stone  floor  without  cellar 7.0 

Thickness  of  wall  is  figured  without  the  air  space,  the  same  being  1 
Sandstone  about  5  inches  thick,  included  in  the  thickness  of  the  wall. 
Thickness  of  glass  between  usual  limits  has  no  influence. 


25" 
4.35 
3.60 
5.00 
4.25 

36" 
5.99 
7.25 


30" 
3 .75 
3.20 
4.25 
3.50 

40" 
5.45 

6.80 


35" 
3.25 

2.85 
3.70 
3.00 

44" 
5.10 
6.40 


40" 
3.85 
2.55 
3.25 
2.50 


48" 
4.75 
5.95 


B.T.U. 

Single  windows 25 . 5 

Single  windows  with  double  panes. .  15.0 

Double  windows 11.5 

Single  skylight 26 .5 

Double  skylight 12.0 

Doors 10.0 

to  2^  inches. 


METALS 
Aluminum  .  .  123-130 


Relative  Heat  Conductivity. — The  following  relative  coefficients  of  the  internal 
conduction  of  heat  of  some  substances  are  given  by  Neumann,  Forbes,  Peclet,  Lorenz, 
etc. 

Wood  ashes 

Charcoal,  powdered 

Pumice,  loose,  for  insulation 

Pumice  stone  for  insulation . 

Limestone,  fine 

Siliceous  sinter 

Cork 

Cork,  mass 

Chalk,  powdered 

Leroy's  mass  . 


Antimony 

Lead  (28.5  average) 

Bronze 

Iron  (55  average  value)  .  .  . . 
Steel  (22-40  average  value) 
Gold  .  . 


14-16 
50-72 
90-100 
50-72 
22-50 
200 


0. 


Copper  (330  average  value) 260-396 


Brass 

German  silver 
Platinum  .  .  . 
Mercury  .... 

Silver 

Bismuth  . 


72-108 

26-32 

33 

6-7 

400 

6 

Zinc  (105  average  value) 92-105 

Tin  (45  average  value) 51-55 

OTHER  SUBSTANCES 

Brick  masonry 0 .69-0 .70 

Cotton  (pressed) .  0.01-0.04 

Stone  masonry 1.3-2.1 

Cement 0.6 

Coke,  dense 5.0 

Coke,  powdered 0 . 16 

Oak  (along  the  fiber) 0 .21 

Ice 0.8 

Felt 0 .03-0 .05 

Plaster  of  Paris 0.33-0.63 

Plastered  plank 0.4  -0.515 

Glass 0.75-0.88 

vJlass,  by  Bectz 0 . 16 


0.06 

0.08 

0.066 

0.083 

17-21 

0.136 

14-0.25 

0.08 

0.09 

0.091 

Air  (inclosed) 0 .02-0 .04 

Marble,  fine 3 .48 

Marble,  coarse 2 . 78 

Marble,  by  Forbes 0 . 55 

Paper 0 .034-0 .043 

Quartz  (sand) 0 . 27 

Sawdust 0 .05-0 .065 

Silk  refuse  (for  insulation) 0  .045 

Coal    0.11 

Pine,  along  the  fiber 0.17 

Pine,  across  the  fiber 0.1 

Clay  (burnt) 0.5-0.7 


Wool 


LIQUIDS 

Ether 

Alcohol 

Glycerin 

Solution  chloride  sodium,  specific 

gravity  1.178 

Olive  oil 

Water  . . 


0.4 


0.15 
0.18 
0.24 

0.14 
0.49 
0.51 


424  GAS   PRODUCERS 

COEFFICIENTS  OF  HEAT  CONDUCTIVITY    PER  SQUARE    METER    PER    HOUR  DEG.  C. 

Calories. 

Masonry 1 . 3  to  3 . 1 

Fire  brick 0.7 

Air 0.0175  to  0.0205 

Cement 0.059 

Water 0.44  to  0.56 

Iron 40  to  70 

Copper 330.00 


The  conductivity  of  fire-brick  increases  with  the  temperature,  that  of  incandescent 
brick  approximating  that  of  iron; 

The  Harbison- Walker  Refractories  Company,  of  Pittsburg,  Pa.,  have  conducted 
several  experiments  on  heat  conduction  and  find  that  fire-clay  brick  is  the  poorest  con- 
ductor, followed  by  silica  brick,  chrome  brick  and  magnesia  brick,  the  magnesia  brick 
being  the  best  conductor. 

If  measured  by  the  number  of  minutes  required  for  the  heat  of  a  Bunscn  burner  to 
pass  along  the  brick,  and  melt  a  ball  of  wax,  the  comparison  of  the  different  materials 
is  about  as  follows: 

Minutes. 

Fire-clay  brick 59 

Silica 48 

Chrome 34 

Magnesia 17 

Magnesia  brick  is  such  a  good  conductor  of  heat  that  it  must  be  invariably  backed 
up  with  clay,  silica  or  chrome  brick  in  furnace  construction.  Magnesia  brick  should 
never  be  laid  against  the  metal  shell  or  metal  part,  and  should  not  be  used  without  the 
backing-up  necessary  to  prevent  the  radiation  of  heat. 

RELATIVE  VALUE  OF  GOOD  HEAT  CONDUCTORS 

Substance.  Relati!"e 

Value. 

Silver ' 100 

Copper 73 . 6 

Brass 23.1 

Iron 1.91 

Steel 11.6 

Platinum 8.4 

Bismuth 1.8 

Water.  0.147 


HEAT:   TEMPERATURE,  RADIATION,  AND   CONDUCTION 


425 


RELATIVE    VALUE   OF   HEAT   INSULATORS 

Substance.  Relative  Insulating 

\  a  me. 

Silicate    cotton  or  slag  wool 100 

Hair  felt 85.4 

Cotton  wool 82 

Sheep's  wool 73 . 5 

Infusorial  earth 73 . 5 

Charcoal 71.4 

Sawdust 61.3 

Gas-works  breeze 43 . 4 

Wood,  and  air-space 35. 7 

The  importance  of  agitation  in  connection  with  heat  transference,  which  has 
already  been  alluded  to,  cannot  be  too  strongly  emphasized,  for  upon  it  depends  the 
efficiency,  in  part,  of  the  principles  covering  the  burning  of  gas  under  pressure  by 
which  the  flame  temperature  is  so  materially  enhanced. 

The  rotary  kiln  which  is  particularly  advantageous  when  the  material  to  be  heated 
tends  to  "fine"  early  in  the  process  retarding  heat  transference  through  mass  action. 
The  efficiency  of  the  powdered  fuel  producer  also  lies  along  these  lines. 

The  principle  involved  may  be  seen  experimentally  in  the  use  of  the  Parr  calor- 
imeter, where  the  mechanical  agitation  of  the  water  through  the  use  of  the  revolv- 
ing vanes  is  absolutely  necessary  to  complete  the  heat  transference  between  the  com- 
bustion bomb  and  the  surrounding  water  element  from  which  the  thermometer 
temperatures  are  taken. 

Expansion. — To  find  the  increase  in  the  length  of  a  bar  of  any  material  due  to 
an  increase  of  temperature,  multiply  the  number  of  degrees  of  increase  of  tempera- 
ture by  the  coefficient  for  100°  and  by  the  length  of  the  bar,  and  divide  by  100. 
LINEAR   EXPANSION   OF   SUBSTANCES  BY   HEAT 


Name  of  Substance. 

Coefficient  for 
100°  F. 

Coefficient  for 
180°  F.,  or  100°  C. 

Baywood  (in  the  direction  of  the  grain,  dry)  

0  00026-0  00031 

0  00046-0  00057 

Brass  (cast)           

0  00104 

0  00188 

Brass  (wire)  

0  00107 

0  00193 

Brick  (fire)                         

0  0003 

0  0005 

Cement  (Roman)  

0  0008 

0  0014 

Copper  ....              

0  0009 

0  0017 

Deal  (in  the  direction  of  the  grain,  dry)  

0  00024 

0  000-14 

Glass  (English  flint)  

0  00045 

0  00081 

Glass  (French  white  lead)  

0  00048 

0  00087 

Gold    .  .            

0  0008 

0  0015 

Granite  (average)  

0  00047 

0  00085 

Iron  (cast)                     

0  0006 

0  0011 

Iron  (soft  forged)  

0  0007 

0  0019 

Iron  (wire)  

0  0008 

0  0014 

Lead  .                

0  0016 

0  0099 

Marble  (Carrara)  .  •          

0  00036-0  0006 

0  00065-0  0011 

Mercury                          

0  0033 

0  0060 

Platinum    .  .             

0  0005 

0  0009 

Sandstone  .             

0.0005-0  0007 

0  0009-0  0012 

Silver                 

0  0011 

0  00° 

Slate  (Wales)                            

0  0006 

0  001 

Water  (varies  considerably  with  the  temperature)  

0  0086 

0  01  5  5 

426 


GAS   PRODUCERS 
EXPANSION   OF   METALS.     (FARADAY) 


The  Length  of  a  Bar 

The  Length  of  a  Bar 

At  32°=  1. 

At  212°  = 

Expansion  per 
Deg.  F. 

At32°=l. 

At  212°  = 

Expansion  per 
Deg.  F. 

Brass  

1  .0019062 
1.001745 
1.0011112 
1.0011899 

0.0000106 
0.0000097 
0.0000062 
0.0000066 

Wrought  iron  . 

1  .0012575 
1.002 
1.002942 

0.000007 
0.0000111 
0.0000163 

Copper  .  . 

Tin. 

Cast  iron  

Zinc  

Steel  

Almost  all  bodies  expand  in  equal  proportions  for  each  degree  between  freez- 
ing and  boiling. 

To  ascertain  the  expansion  of  a  body,  multiply  the  dimensions  of  the  body  by 
the  number  of  degrees  of  increase  of  temperature  and  then  by  the  expansion  per 
degree. 

Example. — Required  the  expansion  of  a  steel  rail  30  ft.  long,  with  an  increase 
of  temperature  of  100°. 

30X100  =  3000;  3000X0.0000066  =  .0198  ft.  =  i  in. 


LINEAR   EXPANSION    OF    METALS    PRODUCED    BY    RAISING    THEIR    TEMPERATURE 

FROM   32°  TO   212°  F. 


Zinc 1  part  in  322 


Lead  . 

Tin  (pure)  .  .  . 

Tin  (impure)  . 

Silver 

Copper 

Brass 


351 
403 
500 
524 
581 
584 


Gold 1  part  in    682 


Bismuth 

Iron 

Antimony  . 
Palladium 
Platinum  . 
Flint  glass 


719 

812 

923 

1000 

1100 

1248 


EXPANSION   OF   LIQUIDS  IN   VOLUME 

Volume  at  32°  F.  =  l.  Volume  at  212°  F.= 

Water 1 .046 

Oil 1.080 

Mercury 1 .018 

Spirits  of  wine 1.110 

Air.  .  .    1.373-1.375 


Non-freezing  Solution. — The  principal  non-freezing  solut.ons  are  the  following: 
Brine  (the  objection  to  which  is  its  tendency  to  oxidize).  Glycerine  and  water  is  a 
mixture  much  used  in  France,  which  will  stand  fairly  low  temperature,  and  which 
necessitates  the  use  of  chemically  pure  glycerine  to  prevent  the  contact  of  fatty  acids, 
particularly  corrosive,  especially  with  rubber. 

Wood  alcohol,  which  has  a  freezing  point  of  151°  F.  below  zero,  and  which  may 
be  used  under  ordinary  circumstances  mixed  with  water,  however,  possesses  a  par- 
ticularly low  boiling  point,  but  is  inclined  to  evaporate. 


HEAT:    TEMPERATURE,  RADIATION,  AND   CONDUCTION  427 

Another  non-freezing  solution  is  calcium  chloride,  which  on  ordinary  metals  has 
little  or  no  corrosive  action,  and  when  dissolved  in  water  makes  a  colorless  and  odor- 
less solution  as  follows : 

Calcium  chloride  to  each  gallon,  Ib 2       2^     3         3^     4         4*         5       5* 

Degrees  salometer, 18     4       88       95     104     120     124     12 

Freezing  point,  F 52     80     150       8       17       39       27     27 

The  calcium  chloride  is  a  waste  product  in  the  manufacture  of  salt,  and  is  there- 
fore cheap,  and  the  impurities  having  been  removed  should  be  entirely  harmless. 

It  is  also  an  excellent  solution  for  use  in  exposed  water  seals,  lutes  and  boshes. 


CHAPTER  XIX 
HEAT  MEASUREMENTS:    PYROMETRY  AND   CALORIMETRY 

PYROMETRY 

THE  application  of  a  pyrometer  to  the  bed  of  a  gas  producer  is  a  more  less  difficult 
operation,  for  the  following  reasons : 

The  testing  instrument  must  be  inserted  horizontally,  that  is  to  say,  from  the 
side  of  the  producer,  for  should  the  sound  or  contact  be  connected  from  the  top  and 
pass  down  through  the  fuel,  there  would  be  a  tendency  to  form  a  draft  hole,  the 
draft  following  along  the  sides  of  the  sound  in  a  chimney  or  channel,  and  thereby 
causing  abnormal  combustion  and  reflecting  an  undue  showing  of  heat. 

Again,  when  the  contact  point  is  made  from  the  side  of  the  producer,  it  must 
be  remembered  that  the  tendency  of  all  drafts  is  to  follow  the  walls,  and  the  tem- 
perature immediately  adjacent  to  the  walls,  on  this  account,  together  with  a  certain 
amount  of  reverberation,  is  apt  to  give  an  excess  or  inaccurate  result.  Great  care 
should  be  observed  in  noting  that  the  fire-bed  is  compact  and  free  from  channels. 

There  are  about  three  zones  of  importance  within  the  producer;  namely, 
the  ash,  combustion,  and  distillation  zones,  but  of  these  three  the  combustion  zone 
alone  is  of  particular  interest  from  a  pyrometric  standpoint,  the  conditions  in  the 
other  zones  being  largely  reciprocal. 

The  use  of  a  pyrometer,  especially  of  the  recording  type,  will  be  found  of  great 
value  in  the  regulation  and  operation  of  the  apparatus,  when  empirical  results  have 
once  been  obtained  and  a  standard  operation  established. 

Bristol  Pyrometers. — The  Bristol  electric  pyrometers  can  be  applied  to  pipes, 
mains,  or  tanks  containing  superheated  steam,  liquids,  or  gases  under  pressure.  It 
is  of  the  themo-couple  type. 

For  the  application  of  the  electric  pyrometer  to  cases  of  this  character,  where 
there  is  pressure  of  either  steam,  liquids,  or  gases,  a  well,  provided  with  a  screw,  is 
inserted  through  the  wall  of  the  pipe  or  tank  in  which  the  temperature  is  to  be  meas- 
ured. The  illustration  shows  how  the  couple  is  generally  applied  in  a  case  of  this 
kind  by  simply  inserting  it  into  the  well  from  the  outside. 

These  couples  are  made  in  two  parts — fire  end  and  extension  piece.  The  two 
parts  are  joined  together  by  a  separable  junction  and  may  be  designed  of  almost 
any  desired  length  and  form  to  meet  the  individual  requirements.  The  general 
construction  and  simplicity  of  the  couple  and  leads  are  shown  in  the  illustration 
of  the  fire  end  in  a  horizontal  and  the  extension  piece  in  a  vertical  position  with 

428 


HEAT    MEASUREMENTS:    PYROMETRY    AND  CALORIMETRY        429 


leads  attached  and  ready  to  connect  with  the  indicating    instrument    by  means  of 
an  ordinary  lamp  plug. 


Pyrometer  Couple*. 


Screic  Joint  for  Leads  to  Iiisti'umcnt 


or  Tank 


FIG.  205. — Couple  of  Bristol  Electric  Pyrometer. 

The  fire  end  may  be  attached  to  or  detached  from  the  extension  piece  in  a  few 
seconds  by  means  of  the  separable  junction,  as  shown  in  detail  in  the  following, 
figure. 


FIG.  206. — Bristol  Pyrometer  Connections. 

This  feature  is  of  great  practical  value  and    makes  it  possible  to  conveniently 
detach  and  cheaply  renew  the  fire  end  when  desired.     These  fire  ends  are  generally 
made  up  of  two  special  alloys  which  will  with- 
stand   high    temperatures  and  are  equipped 
with  fire-proof  insulation. 

The  extension  piece  is  thus  a  part  of  the 
couple  itself  and  the  cold  end  of  the  couple 
is  where  the  extension  piece  terminates  and 
is  joined  to  the  lead  wires.  It  is  a  well- 
known  fact  that  in  using  any  thermo- 
couple the  cold  ends  of  the  elements  should 
be  maintained  at  a  constant  temperature,  or 
a  correction  should  be  made  based  on 
the  changes  of  temperature  at  the  cold 
end.  The  extension  piece  provides  for  carry- 
ing the  cold  ends  to  a  point  near  the  floor  where  the  atmospheric  temperature 
will  be  practically  constant  and  not  influenced  by  the  temperature  which  is  being 
measured. 


FIG.  207. — Connection  C  of  Fig.  206. 


430 


GAS   PRODUCERS 


In  standardizing  or  calibrating  the  Bristol  pyrometers  it  is  usually  assumed 
that  the  temperature  at  the  cold  end  will  average  75°  F.  A  great  number  of  exper- 
iments have  shown  that  this  temperature  can  usually  be  secured,  but  if  the  cold 
end  temperature  is  found  to  vary  considerably  from  that  for  which  the  individual 
pyrometer  was  standardized,  and  great  refinements  of  measurements  are  desired, 
a  very  simple  correction  can  be  made  of  the  readings  of  the  instrument.  In  the 
majority  of  cases  this  variation  is  found  to  be  so  slight  that  it  is  not  necessary 
to  make  corrections,  but  the  rule  for  corrections  is  as  follows  when  the  special  alloys 
are  used:  Subtract  the  difference  from  the  reading  as  indicated  by  the  instrument 
at  that  moment. 

In  most  cases  the  conditions  are  such  that  the  pyrometers  can  be  standardized 
for  a  cold  end  temperature  of  75°  F.  to  the  greatest  advantage,  but  they  may  be 
standardized  for  any  other  average  cold  end  temperature. 

Though  the  sectional  couple  can  usually  be  applied  in  such  a  way  as  to  avoid 
the  necessity  for  making  corrections  for  the  cold  end  temperature,  yet  it  is  sometimes 


THERMO-ELECTRIC 


LEADS   TO  INDICATING   INSTRUMENT 


FIG.  208. — Temperature  Correction 
Device. 


FIG.  209. — Position  of  Fig.  208  in  the  Circuit. 


extremely  desirable  to  have  such  corrections  made  automatically,  thus  insuring 
great  refinement  of  measurement.  It  is  possible  to  accomplish  this  by  the  use  of 
the  automatic  compensators. 

The  compensator  consists  of  a  small  glass  bulb  and  capillary  tube  partially 
filled  with  mercury  into  which  a  short  loop  of  fine  platinum  resistance  wire  dips. 
Changes  in  temperature  causing  expansion  or  contraction  of  the  mercury  have  the 
effect  of  changing  the  resistance  offered  by  this  loop  since  the  rise  and  fall  of  the 
mercury  short  circuits  more  or  less  of  the  resistance  wire. 

The  relative  position  of  the  compensator  is  shown  connected  in  the  circuit. 
In  actual  practice  the  compensator  is  attached  at  the  cold  end  of  the  couple  at  the 
end  of  the  extension  piece.  The  figure  shows  the  compensator  attached  to  the  cold 
end  of  a  straight  couple  without  extension  piece.  When  the  temperature  at  the 


HEAT   MEASUREMENTS:    PYROMETRY   AND  CALORIMETRY       431 

cold  end  rises  the  mercury  expands  and  thereby  cuts  down  the  resistance  of  the 
circuit.  Thus  the  change  in  resistance  in  the  compensator  balances  the  change  in 
electromotive  force  and  the  indications  on  the  instrument  will  remain  the  same  as 
if  no  change  of  atmospheric  temperature  had  occurred. 

This  thermo-electric  couple  has  been  designed  to  do  the  work  of  the  expensive 
platinum  platinum-rhodium  couple,  which  is  necessary  for  use  in  high  temperature 
measurements.  By  the  use  of  inexpensive  alloys  for  the  part  of  the  couple  which 
is  not  exposed  to  a  temperature  above  a  red  heat,  a  great  saving  of  platinum  is 
possible,  as  only  the  active  part  of  the  couple  is  made  of  the  precious  metal. 


LEADS  TO  INSTRUMENT 


EXTENSION  OF 
COUPLE 


FIG.  210. — Arrangement  for  Testing  Molten  Metals. 

The  thermo-electric  junctions  B  and  C  are  introduced  into  the  circuit  where 
the  low-priced  alloys  and  platinum-rhodium  elements  are  connected,  but  by  employ- 
ing proper  alloys  the  electromotive  forces  generated  are  equal  and  opposed.  The 
resultant  electromotive  force  produced  will  therefore  be  the  same  as  if  the  entire 
length  of  the  couple  was  made  of  the  very  expensive  platinum-rhodium  elements. 

When  the  tips  of  these  elements  are  slightly  immersed  into  molten  metal,  an 
electric  connection  is  made  and  the  reading  on  the  instrument  will  be  the  same  as  if 
the  couple  had  been  originally  joined. 

The  general  arrangement  of  the  parts  forming  the  complete  outfit  for  this  class 
of  temperature  measurement  is  shown  in  the  accompanying  diagram,  as  it  would 
be  applied  for  taking  the  temperature  of  a  crucible  of  molten  metal  just  before 
pouring. 


432 


GAS   PRODUCERS 


The  advantage  of  this  plan  is  that  the  tips  of  the  wires  forming  the  elements 
almost  instantaneously  assume  the  temperature  of  the  molten  metal  and  time  lag 
error  is  eliminated. 

This  form  of  couple  has  been  most  successfully  applied  to  the  measurement 
of  molten  metals  as  cast  iron,  copper,  aluminum,  brass,  bronze,  and  other  alloys. 

When  the  tip  of  the  couple  becomes  worn  away  by  continued  use,  a  fresh  portion 
is  exposed  to  the  molten  metal  and  the  reading  will  be  the  same  as  if  the  couple 
had  not  worn  away. 


FIG.  211. — Position  of  Pyrometer  in  Furnace. 

In  many  instances  it  is  desirable  to  have  means  of  quickly  determining  the 
temperature  of  the  surface  of  an  object.  The  special  feature  of  the  couple  for  this 
work  consists  in  having  the  elements  disconnected  and  reduced  to  fine  points  at 
the  ends.  When  contact  is  made  with  the  surface  of  the  object  whose  temperature 
is  to  be  measured,  the  fine  points  of  the  elements  almost  instantaneously  acquire  the 
temperature  of  the  object,  and  if  it  is  metallic  it  will  serve  to  make  the  electric 
connection  between  the  elements  so  that  the  reading  may  be  taken  without  delay. 


HEAT   MEASUREMENTS:    PYROMETRY   AND   CALORIMETRY       433 

If  the  object  to  be  measured  is  a  non-conductor  of  electricity  a  very  thin  piece 
of  metal  should  be  placed  on  the  surface  before  applying  the  couple. 

A  special  combination  of  the  indicating  and  recording  pyrometers  has  been 
designed  for  cases  where  it  is  desirable  to  have  a  single  couple  or  fire  end  actuate 
both  kinds  of  instruments.  It  has  been  found  not  only  possible,  but  entirely  prac- 
tical, to  so  arrange  the  Wm.  H.  Bristol  electric  pyrometers,  that  both  the  indicating 
and  recording  instruments  can  be  connected  to  and  calibrated  for  the  same  thermo- 
couple. In  order  that  either  instrument  may  be  detached  from  the  other  instru- 
ment and  leads  at  any  time,  a  special  checking  system  has  been  devised  with  switches 
so  that  either  instrument  can  be  taken  out  of  service  without  interfering  with  the 
other,  and  either  one  tested  as  to  its  individual  accuracy  at  any  time.  For  cases 
where  the  indicating  instrument  is  needed  by  the  operator  at  his  post  of  duty,  and 
it  is  also  desirable  for  the  superintendent  to  have  definite  information  regarding  the 
temperatures  night  and  day,  this  combination  unit  has  been  used  to  great  advantage. 

The  fire  end  of  the  pyrometer  is  applied  through  an  opening  in  the  side  of  the 
kiln  or  flue.  The  couple  itself  is  generally  inclosed  in  a  protecting  well  of  wrought 
iron  pipe  with  the  end  closed  for  temperatures  below  2000°  F.  For  temperatures 
above  2000°  special  protections  of  porcelain,  graphite  or  fused  quartz  are  used. 

For  temperatures  that  average  above  a  red  heat  (1000°  F.)  an  extra  wrought 
iron  protecting  pipe  well  is  recommended  for  the  fire  end,  as  described  and  illus- 
trated in  connection  with  the  oven  furnace  illustrated  below. 

The  extension  piece  BD  of  the  thermo-electric  couple  is  joined  to  the  fire  end  as 
shown  in  Fig.  53,  when  the  cold  end  of  the  couple  D  can  thus  be  located  at  a  point 
where  it  will  not  be  affected  by  the  variations  of  temperature  in  the  kiln  or  flue. 

The  sectional  view  of  an  oven  furnace  indicates  how  the  fire  end  of  the  pyrometer' 
should  be  applied,  using  an  extra  protecting  iron  pipe  with  closed  end.     This  extra 
protecting  pipe  can  be  renewed  as  often  as  necessary,  thus  saving  the  couple  and 
its  initial  pipe  protection  from  injury  when  in  continuous  service.     The   extra  iron 
pipe  wells  can  be  easily,  quickly,  and  cheaply  made  in  an  ordinary  blacksmith  forge. 

An  extension  piece  of  the  couple  is  shown  attached  to  the  fire  end,  wrhich  affords 
a  practical  method  of  keeping  the  cold  end  of  the  couple  below  and  away  from  the 
influence  of  the  variations  of  temperature  in  the  furnace. 

As  compared  with  other  forms  of  apparatus  for  measurement  of  high  tem- 
peratures, the  thermo-electric  pyrometer  has  many  advantages,  of  which  the  follow- 
ing according  to  the  makers,  are  the  most  important : 

They  may  be  employed  where  the  space  is  extremely  small  and  inaccessible. 

The  indicating  or  recording  instrument  can  be  located  at  the  most  convenient 
point,  at  almost  any  distance  from  the  couple. 

They  are  practically  independent  of  temperature  variations  intermediate  of 
their  hot  and  cold  ends. 

They  are  independent  of  pressure  and  rough  usage  at  the  point  where  the  tem- 
perature is  desired  to  be  measured. 

They  are  extremely  sensitive  to  changes  of  temperature  and  respond  instantan- 
eously, that  is,  there  is  no  time-lag  error. 

They  are  constant  in  their  indications  when  the  couples  are  properly  protected. 

They  permit  the  determination  of  the  temperature  at  many  different  points  by 


434 


GAS   PRODUCERS 


means  of  several  couples  and  leads  connected  to  one  instrument,  provided  with 
suitable  switching  device. 

The  important  advantages  of  the  low  resistance  thermo-electric  pyrometer 
system  may  be  summarized  as  follows: 

1.  A  commercial  switchboard  or  portable  dead-beat  indicating  instrument  may 
be  employed  instead  of  the  extremely  delicate  suspension  galvanometer  required 
for  use  with  a  single  platinum-rhodium  couple.  This  advantage  is  gained  by  the 
fact  that  the  thermo-electric  couples  employed  give  several  times  as  much  electromo- 
tive force  as  the  platinum-rhodium  couples,  which  is  ample  to  successfully  operate 
a  pivot  instrument  if  of  sufficiently  low  resistance. 


FIG.  212. — Bristol  Secondary  Electric  Pyrometer  complete. 

2.  The  low  resistance  of  the  special  couples  makes  a  high  resistance  galvanom- 
eter unnecessary. 

3.  The  low  resistance  pivot  instruments  may  be  read  in  vertical   or  horizontal 
positions,   and  do   not   require  any   firm  foundation  or  leveling,   and  may  even  be 
read  when  carried  in  the  hand. 

4.  It  affords  a  practical  method  for  automatically  compensating  for  the  changes 
of  temperature  at  the  cold  ends  of  the  couple. 

5.  It  makes  it  practicable  to  use  the  same  indicating  instrument  and  the  same 
couple   for  different   total   ranges    of    temperature,   by  using  different    binding   posts 
and  having  several  scales  drawn,  the  proper  resistances  being  inserted  for  each  indi- 
vidual total  scale. 


HEAT  MEASUREMENTS:    PYROMETRY   AND  CALORIMETRY        435 

6.  The  application  of  low-priced  metals  and  alloys  as  a  substitute  for  platinum 
and  rhodium  makes  it  possible  to  instal  a  number  of  couples,  and  by  means  of  proper 
switching  devices   quickly   determine  the  temperatures   at  the    locations   of  the   dif- 
ferent couples.     In  many  instances  the  first  cost  of  the  expensive  platinum  elements 
prohibit  their  use  in  this  way. 

7.  This  system  also   makes  it  possible   to  use  the  patented   compound   couple 
with  low-priced  metals  and  alloys  as  a  substitute  for  a  portion  of  the  couple  where 
extremely   high    temperatures    are    to    be    measured    requiring   the    use    of   platinum 
platinum-rhodium  elements. 

8.  The  low  resistance  system   makes   it  possible  to  use  a  pivot  bearing  galva- 
nometer arranged  to  record  on  the  patent  smoked  chart. 


SEGER  FIRE-CLAY  CONES 

The  freezing  points  of  cones  made  of  specified  mixtures  of  refractory  clays  can 
be  used  to  determine  the  temperatures  of  highly  heated  spaces.  The  following 
tables  gives  the  composition  of  such  cones  and  the  corresponding  temperatures  at 
which  they  fuse  at  the  edges  or  the  points  soften  and  bend  over. 


TABLE   OF  MELTING-POINTS  OF   SEGER  CONES 


Cone  No. 

Deg.  C. 

Degrees  F. 

Cone  No. 

Degrees  C. 

Degrees  F. 

010 

950 

1742 

14 

1410 

2570 

09 

970 

1778 

15 

1430 

2606 

08 

990 

1814 

16 

1450 

2642 

07 

1010 

1850 

17 

1470 

2678 

06 

1030 

1886 

18 

1490 

2714 

05 

1050 

1922 

19 

1510 

2750 

04 

1070 

1958 

20 

1530 

2786 

03 

1090 

1994 

21 

1550 

2822 

02 

1110 

2030 

22 

1570 

2858 

01 

1130 

2066 

23 

1590 

2894 

1 

1150 

2102 

24 

1610 

2930 

2 

1170 

2138 

25 

1630 

2966 

3 

1190 

2174 

26 

1650 

3002 

4 

1210 

2210 

27 

1670 

3038 

5 

1230 

2246 

28 

1690 

3074 

6 

1250 

2282 

29 

1710 

3110 

7 

1270 

2318 

30 

1730 

3146 

8 

1290 

2354 

31 

1750 

3182 

9 

1310 

2390 

32 

1770 

3218 

10 

1330 

2426 

33 

1790 

3254 

11 

1350 

2462 

34 

1810 

3290 

12 

1370 

2498 

35 

1830 

3326 

13 

1390 

2534 

36 

1850 

3362 

436 


GAS   PRODUCERS 


SEGER  CONES— (THE  STOWE-FULLER  Co.) 
CONE  No.         CHEMICAL  FORMULA.  MIXTURE. 


Feldspar 

83 

.55 

1 

0.3K2O\ 
O.TCaO/ 

J0.2Fe203 
\0.3A12O3 

J4Si02 

Marble 
Quartz 

35 
66 

.00 
.00 

Iron  oxide 

16 

.00 

Feldspar 

83 

.55 

2 

0 
0 

3K,O1 
.  7CaO  J 

JO 

to 

.  !Fe2O3 
.4AljO, 

j  4SiO2 

Marble 
Quartz 
Iron  oxide 

35 
60 

8 

.00 
.00 
.0 

Zettlitz  kaolin 

12 

.95 

Feldspar 

83 

.55 

3 

0 

0 

.3K,O\ 
.7CaOJ 

/o 
lo 

05Fe203\ 
.45A1,0,/      °J 

Marble 
Quartz 
Iron  oxide 

35 
57 
4 

.00 
.00 
.00 

Zettlitz  kaolin 

19 

.43 

Feldspar 

83 

.55 

4 

0 
0 

3K2O\ 
.7CaO/ 

0 

•  5A12O3, 

4SiO, 

Marble 
Quartz 

35 
54 

.00 
.00 

Zettlitz  kaolin 

25 

.90 

Feldspar 

83 

.55 

5 

0 
0 

.3K2O1 
.7CaO/ 

0 

5Al2Oa, 

5SiO2 

Marble 
Quartz 

35 

84 

.00 
.00 

Zettlitz  kaolin 

25 

90 

Feldspar 

83 

55 

6 

0 
0 

3K2O  \ 
7CuO  / 

0.6A12O3, 

GSiO, 

Marble 
Quartz 

35 
108 

00 
0 

Zettlitz  kaolin 

38 

85 

Feldspar 

83 

55 

7 

0 
0 

3K,() 
7CaO  / 

0.7ALA,, 

7SiO. 

Marble 
Quartz 

35 
132 

00 
00 

Zettlitz  kaolin 

51 

80 

Feldspar 

83 

55 

8 

0 
0 

3K2O  \ 
7CaO  / 

0 

8A12O3, 

8SiO2 

Marble 

Quartz 

35 
156 

00 
00 

Zettlitz  kaolin 

64 

75 

Feldspar 

83 

55 

9 

0 
0 

3K2O  \ 
7CaO  f 

0. 

9ALA, 

9SiO2 

Marble 
Quartz 

35 
180. 

00 
00 

Zettlitz  kaolin 

77. 

70 

Feldspar 

83. 

55 

10 

0. 
0. 

3K2O  \ 
7CaO  / 

1. 

OAUO3, 

10SiO2 

Marble 
Quartz 

35. 
204. 

00 
00 

Zettlitz  kaolin 

90 

65 

Feldspar 

83. 

55 

11 

0. 
0. 

3K/)1 

7CaO  J 

1.2A12O3, 

12SiO2 

Marble 
Quartz 

35. 
252. 

00 
00 

Zettlitz  kaolin 

116. 

00 

HEAT  MEASUREMENTS:    PYROMETRY  AND   CALORIMETRY        437 


SEGER   CONES—  (Continued) 
CONE  No.         CHEMICAL  FORMULA.  MIXTURE. 


Feldspar 

83.65 

12 

0 

0 

.3K,O\ 

.7CaOj 

1.4A1,03. 

14SiO? 

Marble 
Quartz 

35.00 
300.00 

Zettlitz  kaolin 

142.45 

Feldspar 

83.55 

13 

0 
0 

3K20  1 
7CaO  / 

1.6A12O3, 

16S1O, 

Marble 
Quartz 

35.00 
348.00 

Zettlitz  kaolin 

168.35 

Feldspar 

83.55 

14 

0 
0 

3K2O  1 
7CaOJ 

1.8A12O3, 

18S1O 

Marble 
Quartz 

35.00 
396.00 

Zettlitz  kaolin 

194.25 

Feldspar 

83.55 

15 

0.3K2O\ 
0.7CaO/ 

2.1A12O3,- 

21SiO2 

Marble 
Quartz 

35.00 
468.00 

Zettlitz  kaolin 

233  .  10 

Feldspar 

83.55 

16 

0.3K2O\ 
O.TCaOJ 

2.4A1A, 

24SIO, 

Marble 
Quartz 

35.00 
540.00 

Zettlitz  kaolin 

271.95 

Feldspar 

83.55 

17 

0 
0 

3K2O  ^ 
7CaO  / 

2.7Al2O,i 

27SiO2 

Marble 
Quartz 

35.00 
612.00 

Zettlitz  kaolin 

310.80 

Feldspar 

83.55 

18 

0 
0 

:<K.,0 
7CaO  / 

3  .  1A12O3, 

3lSiO2 

Marble 
Quartz 

35.00 
708.00 

Zettlitz  kaolin 

362.60 

Feldspar 

83.55 

19 

0 
0 

:iK,0 
7CaO  / 

3.5A12O3, 

35SiO2 

Marble 
Quartz 

35.00 
804.00 

Zettlitz  kaolin 

414.40 

Feldspar 

83.55 

20 

0 
0 

3K2O1 
7CaO 

3.9A12O3, 

39SiO2 

Marble 
Quartz 

35.00 
900.00 

Zettlitz  kaolin 

466.20 

Feldspar 

83.55 

21 

0 
0 

3K2O  I 
7CaO 

4.4A12O3, 

44SiO2 

Marble 

Quartz 

35.00 
1020.00 

Zettlitz  kaolin 

530.95 

Feldspar 

83.55 

22 

0 

0 

3K2O\ 
7CaO  / 

4.9A12O3, 

49SiO2 

Marble 

Quartz 

35.00 
1140.00 

Zettlitz  kaolin 

595.70 

438 


CONE  No. 


GAS   PRODUCERS 

SEGER  CONES—  (Continued) 
CHEMICAL  FORMULA.  MIXTURE. 


23    |j 

Feldspar               83.55 

.3K2O\      r   iAir»     ^4«;n    Marble                   35.00 
•rrt  V»  f      5.4AyJs,  54bi(J2  0 
.7CaO  J                                      Quartz               1260.00 

Zettlitz  kaolin    660.45 

24   £ 

Feldspar               83  .  55 

.3K,O\      c  f\\\r\     rnvn    Marble                   35.00 
,^,  "^  I      D.OAlsUj,  oOfeiO,   „ 
.7CaOJ                                      Quartz               1404.00 

Zettlitz  kaolin    738.15 

25    ° 

Feldspar               83.55 
.3K2O\      r.  ,>Air»     rre-r>    Marble                   35.00 
.7CaO/          °A1A'  6     !l°2  Quartz               1548.00 
Zettlitz  kaolin    815.85 

26    jj 

Feldspar               83.55 

.3K2O  \      ~  2A1  O     72SiO    Marb^e                    35.00 
.7CaO/                                  2  Quartz               1692.00 
Zettlitz  kaolin    893.55 

27    ^ 

Feldspar               83  .  55 
.3K7O\      .7nAin     onn«;n    Marble                   35.00 
.7CaO/              2°3'     °l     °2  Quartz               4764.00 
Zettlitz  kaolin  2551  .  13 

28 

Al  0     lOSiO                   Quartz                 240.00 

/VloV_/q.       lUOlW?                                        T-,      ,    .  !  .  ,         i              •,,               -   -,.        _  „ 

Zettlitz  kaolin    129.50 

29 

41  n       »«,-n                  Quartz                 180.00 
Zettlitz  kaolin    129.50 

30 

Ai  0       6SiO                   Quarts                  120.00 
Zettlitz  kaolin    129.50 

31 

AI  n       iv^in                  Quartz                   90.00 
Zettlitz  kaolin    129.50 

32 

Al  O       4SiO                   Quartz                   60.00 
Zettlitz  kaolin    129.50 

33 

AI  n       Q«,T»                  Quartz                   30.00 
Zettlitz  kaolin    129.50 

34 

Al  O    2  5SiO                   Quartz                    15.00 
Zettlitz  kaolin     129.50 

35 

Al  A.  2SiO2                   Zettlitz  kaolin 

36 

Rackonitz  shale  clay 

The  melting  of  these  tetrahedrons  determines  the  temperatures  between  the  melting-point  of 
90  gold,  10  platinum,  (that  is,  about  1145°)  and  the  highest  heat  of  the  porcelain  fire.  The  tem- 
peratures which  correspond  to  the  melting-points  of  the  cones  21  to  26  are  reached  in  the  iron  and 
steel  industries.  The  cones  26  to  36  serve  for  the  determination  of  the  refractoriness  of  clays. 


HEAT   MEASUREMENTS:    PYROMETRY   AND  CALORIMETRY 

Heraeus-LeChatelier  Pyrometer. — The  Heraeus-LeChatelier  Pyrometer  consists 
of  an  element,  the  one  wire  of  which  is  of  pure  platinum  and  the  other  wire 
of  the  10%  rhodium-platinum  alloy,  both  one  millimeter  thick,  the  two  wires  fused 
together  at  one  end  to  a  small  ball.  The  free  ends  of  the  element  are  connected 
to  the  terminals  of  a  delicate  galvanometer,  and  the  current  generated  in  the  heat- 
ing of  the  ball  measured  on  a  suitable  scale  provided  for  in  the  galvanometer,  to 
read  in  millivolts  and  degrees  Centigrade  or  Fahrenheit,  as  desired. 

In  connecting  the  wires  of  the  thermo-couple  to  the  galvanometer  care  should 
be  taken  to  get  the  soft  or  platinum  wire  to  the  negative  binding  post  of  the  galva- 
nometer, and  the  harder  platinum-rhodium  wire  to  the  positive  side.  If  this  is  not 
done,  the  needle  will  swing  in  the  wrong  direction.  If  the  galvanometer  is  placed 
at  some  distance  from  the  point  at  which  the  temperature  is  to  be  measured,  copper 
leads  are  interposed.  These  should  be  of  no  greater  resistance  than  one  ohm,  no 
matter  what  the  distance  may  be.  Below  300  ft.  they  should  be  at  least  No.  12 
Brown  and  Sharpe  gauge  wire. 

Theoretically,  the  temperature  of  the  junction  of  the  copper  leads  with  the  free 
ends  of  the  thermo-couple  should  be  at  the  freezing-point.  Practically,  except  for 
physical  research,  this  matters  but  little  in  the  reading.  Correction  may,  however, 
be  made  by  adding  to  the  galvanometer  readings  one-half  the  difference  from  the  freez- 
ing-point in  degrees  centigrade,  or  nine-tenths  of  the  same  difference  in  degrees 
Fahrenheit.  This  temperature  (of  the  so-called  cold  junction)  can  be  measured 
with  the  ordinary  thermometer,  and  the  rule  holds  good  only  up  to  about  80°  Fahrenheit. 
Hence  great  care  should  be  taken  to  keep  these  junctions  out  of  the  direct  radiation 
of  heated  furnaces. 

If,  through  accidental  abrasion  or  rough  treatment,  the  thermo-couple  becomes 
damaged,  it  can  be  returned  for  repair,  and  the  broken  portions  allowed  for  at  pre- 
vailing scrap  rates.  The  thermo-couple,  however,  should  be  properly  covered  by  a 
protecting  medium  which  will  keep  it  from  direct  contact  with  gases  and  metallic 
vapors,  as  well  as  particles  of  melted  metals,  the  former  ruining  the  platinum  rapidly 
and  the  latter  alloying  at  once  with  the  thermo-couple  to  its  destruction.  The  best 
medium  is  the  highest  grade  of  porcelain,  or  melted  quartz  tubes.  For  ordinary 
uses,  tubes  of  the  Royal  porcelain  manufacture  are  sent  with  the  thermo-couple. 
When  it  is  desired  to  make  temperature  determinations  of  molten  metals,  an  apparatus 
provided  with  a  clay  or  graphite  tip  is  obtainable,  which  answers  every  purpose. 
An  inquiry,  stating  the  conditions  existing,  will  bring  an  estimate  of  all  that  is  needed 
for  the  purpose. 

The  porcelain  tubes  made  by  the  Royal  Porcelain  Works  are  of  such  a  fine 
quality  that  they  will  easily  withstand  temperatures  up  to  the  melting-point  of 
platinum  without  deterioration.  The  hard  silica  glaze  prevents  the  entrance  of 
gases,  and  if  care  is  taken  to  heat  them  up  gradually,  and  not  to  expose  them  to  sudden 
changes,  they  last  very  long. 

Illustrations  are  shown  herewith  of  the  pyrometer  as  arranged  for  the  porcelain 
tube,  and  when  provided  with  the  clay  tip. 

The  galvanometer  used  in  connection  with  the  thermo-couple  of  the  Heraeus' 
LeChatelier  Pyrometer  is  of  the  well-known  D'Arsonval  type.  It  consists  in  the 
main  of  a  permanent  magnet  and  a  suspended  coil  of  wire  (armature)  moving  between 


440 


GAS   PRODUCERS 


its  pole  pieces.  The  terminals  of  the  element  are  connected  to  this  armature,  and 
a  current  flowing  through  them  turns  it  to  an  extent  corresponding  to  the  electro- 
motive force  involved.  The  amount  of  the  deflection  from  the  zero  mark  is  indicated 


by  a  pointer  swinging  over  a  divided  scale  and  there  read  off  directly  as  degrees, 
Centigrade  or  Fahrenheit,  as  may  be  desired.  The  delicacy  of  this  instrument 
requires  that  it  be  handled  with  reasonable  care,  and  if  located  at  some  convenient 
point  where  it  may  be  free  from  injury,  no  difficulty  will  be  experienced.  The 


HEAT  MEASUREMENTS:    PYROMETRY   AND   CALORIMETRY         441 

galvanometer  should  rest  on  a  suitable  foundation,  be  kept  from  jar  and  vibration, 
and  preferably  be  inclosed  in  a  tight  glass  case. 

Recording  galvanometers  are  now  available  for  use  in  connection  with  industrial 
plants  where  it  is  desired  to  note  the  fluctuations  of  temperature  which  have  a  direct 
bearing  on  the  processes  employed.  Even  for  ordinary  boiler  firing  a  record  which 
will  show  up  conditions  in  the  boiler-room  oftentimes  pays  very  well.  In  glass 
works,  blast  furnaces,  and  continuous  heating  or  slow  cooling  of  materials,  a  record- 
ing pyrometer  outfit  will  save  its  first  cost  very  quickly  by  the  improvement  it  will 
bring  about.  The  Heraeus-Le  Chatelier  recording  pyrometer  can  be  arranged  so 
that  it  gives  the  readings  of  five  different  furnaces  simultaneously. 

Fery  Radiation  Pyrometers. — Particularly  suitable  for  temperatures  from  1500° 
F.  upwards.  There  is  no  upper  limit,  as  these  pyrometers  are  capable  of  measuring 
the  highest  temperatures  obtainable. 


FIG.  215. — Section  of  Fery  Radiation  Pyrometer. 

No  part  of  the  pyrometer  has  to  be  inserted  in  the  furnace  or  other  hot  body,  nor 
is  any  portion  of  the  instrument  heated  to  more  than  180°  F.  above  the  surrounding 
air  temperature.  The  result  is  that  the  life  of  this  type  of  pyrometer  is  not  shortened 
by  its  use  in  measuring  very  high  temperatures. 

Long  experience  in  temperature  measurement,  over  a  wide  range  and  under  the 
most  varied  conditions,  has  shown  the  accuracy  and  value  of  such  instruments  and 
the  economies  to  be  effected  by  their  use;  at  the  same  time  the  great  practical  diffi- 
culties to  be  encountered  in  many  cases,  especially  where  temperatures  higher  than 
2200°  F.  are  to  be  measured,  have  shown  the  need  for  a  convenient  and  reliable  form 
of  radiation  pyrometer.  As  is  well  known,  it  is  difficult  to  construct  anything  of 
solid  material  which  can  be  maintained  for  prolonged  periods  at  a  high  temperature 
without  suffering  some  permanent  or  sub-permanent  change  in  its  physical  properties, 
and  as  we  ascend  higher  in  the  temperature  scale  the  difficulties  increase  in  a  quite 
disproportionate  degree.  A  further  aggravation  of  the  trouble  at  high  temperatures 
is  to  be  found  in  the  chemical  activities  of  furnace  products  and  furnace  gases  which 
in  some  cases  render  difficult  the  adequate  protection  of  the  thermo-couple  or  resistance 
wire. 


442 


GAS    PRODUCERS 


With  the  radiation  pyrometer  invented  by  Professor  Fery,  these  difficulties  are 
not  encountered,  the  instrument  being  of  course  placed  at  some  distance  from  the 
furnace,  while  no  part  of  it  is  raised  above  the  air  temperature  by  more  than  180°  F. 


FIG.  216. — Fery  Radiation  Pyrometer  in  Protected 
Case  Sighted  nto  Fire-clay  Test  Hole. 


FIG.  217. — Self-leveling  Indicator  for  Fery 
Pyrometer. 


1800 
FIG.  218.— Scale  of  Fig.  218. 

The  radiation  which  emanates  from  a  hot  body,  or  which  passes  out  through  an 
observation  hole  in  the  wall  of  a  furnace,  falls  upon  a  concave  mirror  and  is  thus  brought 
to  a  focus.  In  this  focus  is  one  junction  of  a  thermo-couple,  whose  temperature  is 
raised  by  the  radiation  falling  upon  it — the  hotter  the  furnace  the  greater  the  rise  of 
temperature  of  the  junction. 


HEAT  MEASUREMENTS:    PYROMETRY  AND  CALORIMETRY        443 

The  arrangement  of  the  instruments  is  such  that  they  are  uninfluenced,  within 
wide  limits,  by  the  size  of  the  hot  body  or  observation  hole  on  the  one  hand,  or  on 
the  other  hand  by  the  distance  which  separates  them  from  the  hot  body  or  furnace. 

The  absorption  of  some  small  amount  of  radiant  heat  in  passing  through  the 
atmosphere  cannot  of  course  be  strictly  without  effect,  but  in  practice  the  error  thus 
arising  is  not  appreciable;  it  has  been  found  for  example  that  the  readings  obtained 


FIG.  219. — Taking  Temperature  of  a  Gas  Retort  by  Fery  Pyrometer. 


for  the  temperature  of  a  body  of  molten  steel  was  precisely  the  same  whether  the 
instrument  was  set  up  3  ft.  or  60  ft.  away. 

The  radiation  pyrometer  is  virtually  a  reflecting  telescope  having  at  a  point  F 
on  its  axis  one  junction  of  a  copper  constant  thermo-couple.  On  this  junction  the 
radiant  heat  of  the  hot  body  under  examination  is  focused  by  the  concave  mirror  M. 
The  two  junctions  of  the  thermo-couple  are  situated  quite  close  together  so  that  they 
partake  equally  in  any  changes  of  atmospheric  temperature,  but  the  "  cold  "  or 
comparison  junction  is  screened  from  the  radiation  focused  by  the  mirror  M.  To 
prevent  over-heating  the  thermo-couple,  when  the  telescope  is  sighted  on  a  very  hot 
body,  a  diaphragm  D  is  provided,  which  can  be  swung  over  the  mouth  of  the 
telescope,  thus  reducing  the  effective  aperture  and  consequently  the  radiant  heat 
falling  on  the  mirror. 


444  GAS   PRODUCERS 

To  guide  the  pointing  of  the  telescope  an  eyepiece  E  is  provided  at  the  rear  and 
through  which  can  be  seen  a  reflected  image  of  the  hot  body.  The  focusing  is  done 
by  means  of  a  milled  head  H  at  the  side  of  the  telescope  and  its  accuracy  verified  by 
observing  the  reflected  image  of  the  hot  body. 

In  the  indicating  outfit  the  telescope  is  mounted  on  a  collapsible  tripod.  To  enable 
temperature  readings  to  be  made  the  thermo-couple  circuit  is  completed  through  a 
short  length  of  flexible  cable  and  an  indicator.  This  indicator  is  an  accurately 
calibrated  millivolt  meter,  which  is  either  automatically  self-leveling  or  does  not 
require  any  leveling. 

It  is  calibrated  to  read  temperature  directly  upon  two  scales,  one  from  1000  to 
2400°  F.,  the  second  from  1800  to  3600°  F.  Centigrade  scales  can  also  be  provided. 
There  is  a  further  calibration  in  millivolts  by  means  of  which  the  sensibility  of  the 
indicator  can  be  checked  when  desired.  The  whole  outfit  is  arranged  to  fold  up  and 
drop  in  a  box,  and  is  easily  carried  by  one  man  as  it  weighs  only  about  30  Ibs. 

One  of  the  illustrations  shows  an  example  of  the  Centigrade  scale  of  the  indicator 
supplied  with  the  portable  outfit. 

The  accuracy  obtainable  with  this  instrument  depends  of  course  to  some  extent 
on  the  observer,  but  assuming  only  ordinary  care  in  sighting  and  reading,  the  accuracy 
should  be  well  within  2%,  in  the  neighborhood  of  say  1800°  F. 

If  the  surrounding  air  temperature  does  not  differ  greatly  from  64°  F.  the  accuracy 
might  be  greatly  increased,  say  to  within  1%,  while  at  all  times  the  power  of  com- 
parison or  discrimination  is  much  finer  than  the  absolute  accuracy.  Reference  to 
the  scale  will  show  that  at  1000°  C.  a  difference  of  5°  C.  would  be  easily  detected. 

In  the  recording  outfit  the  telescope  is  generally  permanently  fixed  in  position  upon 
a  steady  support.  As  it  is  not  usually  convenient  to  have  a  hole  in  a  furnace  wall 
permanently  open,  the  telescope  is  then  cited  into  a  closed  fire-clay  tube  projecting 
well  into  the  furnace  and  of  great  length  compared  with  its  diameter.  When  the 
telescope  is  fixed  in  a  position  out-of-doors  a  weather-proof  cover  is  fitted. 

The  records  are  made  by  a  thread  recorder  which  is  connected  by  twin  cables  to 
the  thermo-couple  in  the  telescope. 

The  Fery  pyrometer  calibration  is  made  by  direct  comparison  with  certified 
standards,  these  standards  being  referred  in  turn  to  those  used  by  the  Bureau  of 
Standards,  Washington.  The  indications  of  the  instrument  are  based  upon  the 
Stefan-Boltzmann  law,  which  states  that  "  the  radiant  energy  emitted  by  a  black 
body  is  proportional  to  the  fourth  power  of  the  absolute  temperature  of  the  body," 
or  in  other  words,  if  we  increase  the  absolute  temperature  of  any  body  by  1%,  we 
shall  increase  the  radiant  energy  it  gives  out  by  4%,  hence  the  great  suitability  of  the 
instrument  to  high  temperature  measurement.  If  the  surface  of  the  hot  body  is  not 
"  black,"  that  is,  if  it  has  reflecting  power,  the  radiation  from  it  will  be  somewhere 
between  that  due  to  its  own  temperature  and  that  due  to  the  temperature  of  its 
surroundings.  This  is  a  fundamental  condition  in  the  laws  of  radiation  and  must 
be  taken  into  account.  The  simplest  way  to  meet  this  condition  is  to  place  the  hot  body 
in  a  nearly  closed  space  where  its  surroundings  are  at  the  same  temperature  as  che 
body  itself.  In  this  way  the  radiation  it  emits  will  be  the  same  no  matter  what  kind 
of  a  surface  the  body  has.  Thus  no  account  of  the  surface  conditions  of  the  hot  body 
need  to  be  taken  when  the  pyrometer  is  sighted  through  a  relatively  small  opening  in 


HEAT    MEASUREMENTS:    PYROMETRY   AND  CALORIMETRY        445 

a  furnace  or  into  a  closed  fire-clay  tube  which  is  deeply  inserted  into  a  furnace.  If, 
however,  the  hot  body  is  out  in  the  open  and  its  surface  is  smooth  and  has  reflecting 
power,  a  special  factor  must  be  used  in  making  the  readings  unless  the  indicator  or 
recorder  is  ordered  calibrated  to  meet  these  conditions.  For  instance,  a  stream  of 
molten  steel  has  a  bright  smooth  reflecting  surface,  and  unless  the  calibration  has  been 
made  for  this  case,  the  reading  on  the  indicator  scale  may  be  as  much  as  25%  lower 
than  the  true  temperature.  In  the  case  of  molten  copper  the  differencce  is  even 
greater. 

This  consideration  is  fully  dealt  with  in  the  instructions  issued  with  every  pyrometer. 

Earnshaw  Blue  Glass  Pyrometer. — This  is  of  the  visual  type,  its  principle  being 
the  absorption  of  light  or  its  diminution,  through  the  use  of  a  varying  number  of 


FIG.  220.— End  Elevation.  FIG.  221.— Side  Elevation. 

EAKNSHAW  ABSORPTION  PYROMETER. 


slides  or  blue-glass  lenses,  to  create  a  vanishing  point  of  light,  said  light  of  course 
presumed  to  vary  directly  as  the  intensity  of  the  heat  observed. 

As  the  personal  equation  is  very  marked  in  the  use  of  an  instrument  of  this  kind, 
its  use  would  of  course  be  of  little  service  in  establishing  absolute  values,  but  it  will  be 
found  of  extraordinary  usefulness  in  making  comparisons  or  establishing  empiric  tests. 
In  other  words,  it  may  be  used  by  either  engineer  or  gas-maker  with  a  far  greater 
degree  of  accuracy  than  the  "  naked  eye  "  for  checking  heats. 

Furnace  Colors. — Pyrometers  are  not  always  at  hand  and  it  is  often  convenient 
to  be  able  to  name  the  temperature  approximately  without  an  instrument.  The 
first  perceptible  red  corresponds  roughly  to  1000°  F. 


446 


GAS   PRODUCERS 


A  dazzling  white  heat  corresponds  roughly  to  3000°  F.  The  eye  is  not  able  to 
distinguish  between  heats  above  3000°  F.,  so  that  anything  which  appears  as  bright 
as  a  gas  mantle,  or  an  incandescent  filament,  or  a  Nernst  glower,  when  working 
properly,  is  at  least  3000°  F. 

In  addition  the  melting-point  of  zinc  is  about  780°  F.;  lead  618°  F.,  and  tin 
445°  F.  Alloys  of  metals  often  have  a  much  lower  melting-point  than  any  of  the 
constituent  metals.  There  are  several  which  will  melt  in  boiling  water.  See  melt- 
ing-points under  the  chapter  on  that  data. 


FIG.  222.— Glass  Disc  Carriers  for  Fig.  221. 

Thermometer  Note. — To  rejoin  a  parted  mercury  column  of  a  low  temperature 
thermometer,  the  mercury  bulb  is  placed  in  ice,  until  the  column  is  no  longer  visible ; 
the  safety  reservoir  at  the  top  of  the  capillary  tube  is  then  carefully  heated  over  an 
alcohol  lamp,  so  as  to  drive  down  the  mercury  it  may  contain.  Then  slightly  heat 
the  large  mercury  bulb  so  as  to  drive  the  mercury  up.  This  however  must  be  done 
cautiously,  and  the  heating  must  cease  at  once  when  the  mercury  is  within  about 
^"  from  the  top.  If  forced  higher  there  is  danger  of  bursting  the  tube. 

After  following  these  directions,  the  column  may  still  be  broken,  in  which  case 
drive  the  mercury  in  the  upper  bulb,  and  then  tap  slightly  sideways  to  cut  the  broken 
column  off.  Repeat  the  tapping  sideways  as  long  as  may  be  necessary  to  rejoin 
the  column  and  finally  cool  the  large  mercury  bulb.  Never  try  to  shake  the  mercury 
down. 


CALORIMETRY 


The  Sargent  Gas  Calorimeter.- — The  Sargent  gas  calorimeter  was  designed  to 
enable  the  operator  to  determine  the  calorific  value  as  well  as  the  foreign  matter  in 
gases,  quickly,  simply,  and  accurately. 

The  section  of  a  calorimeter  shows  the  inlet  water  having  a  constant  head  at  the 
cistern  E,  the  temperature  of  which  is  taken  at  C,  envelops  the  whole  instrument  and 
passes  through  in  the  direction  of  the  arrows  and  the  rise  in  temperature  is  taken 
by  the  thermometer  at  D  before  any  heat  is  lost  by  radiation  to  the  air.  The  com- 
bustion of  gas  takes  place  in  the  central  flue  and  the  products  of  combustion  pass 
to  the  top  and  down  the  annular  chambers  in  the  direction  of  the  arrows,  reaching 
the  temperature  of  the  water  before  passing  out  at  B,  where  a  damper  regulates  the 
Telocity  and  the  thermometer  gives  the  temperature  of  the  exhaust  products. 

The  view  shows  the  calorimeter  complete  as  usually  furnished,  consisting  of  a 


HEAT   MEASUREMENTS:    PYROMETRY   AND   CALORIMETRY        447 


wet  test  gas  meter  with  thermometer  and  manometer,  a  pressure  regulator  with 
micrometer  adjustment,  the  calorimeter  proper  with  three  thermometers,  automatic 
dumping  bucket,  hose,  batteries,  Bunsen  burner,  beaker  etc. 

A  section  of  a  single  unit  dust  determinator  used  to  ascertain  the  grains  of  dust 
per  cubic  foot  in  the  gas  being  tested  is  also  shown.  It  consists  of  two  light  metal 
disks  which  clamp  the  filter  paper  between  gaskets  with  thumb  screws  as  shown. 
Gas  enters  the  opening  in  top  disk  and  spreading  out  passes  through  the  filter  paper, 
leaving  all  dust  and  foreign  matter  on  top  of  paper.  A  wire  gauze  support  in  bottom 
disk  prevents  sagging  and  tearing  of  filter  paper,  should  the  moisture  soften  and  the 
accumulated  dust  tend  to  rupture  it.  Filter  paper  is  weighed  before  and  after  the 
test  and  the  grains  of  dust  per  cubic  foot  of  gas  are  readily  determined. 


FIG.  223. — Section  of  Sargent  Gas  Calorimeter.         FIG.  224. — Sargent  Gas  Calorimeter  Complete. 

The  moisture  is  determined  by  cooling  the  gas  in  a  condenser  and  passing  it 
through  beakers  of  calcium  chloride. 

This  calorimeter  and  auxiliaries  make  a  most  complete  apparatus  for  the  gas 
engineer,  the  manufacturer  of  gas  engines  and  producers,  for  use  in  gas  works  and 
by-products  plants,  and  for  blast  furnace  gas. 

The  advantages  of  the  Sargent  automatic  gas  calorimeter  are  stated  as  follows: 
The  cold  water  enters  and  the  warm  water  discharges  at  the  top,  allowing  the  placing 
cf  the  thermometers  most  frequently  read,  adjacent  to  each  other. 

The  cold  entering  water  envelops  the  water  whose  temperature  is  rising,  thus 
carrying  in  any  radiated  heat. 

The  Bunsen  burner  is  protected  from  drafts  on  all  sides  of  the  base  but  the 
front,  thereby  preventing  irregular  combustion. 

The  thermometers  read  in  tenth  °F.,  insuring  accurate  readings  and  B.T.U.  direct, 
as  no  transformation  from  centigrade  is  necessary. 

Outlet  water  is  weighed,  thereby  eliminating  the  errors  of  measuring  caused  by 
variation  of  temperature,  the  receptacle  being  out  of  level  or  a  varying  meniscus. 


448 


GAS   PRODUCERS 


Gas  pressure  is  controlled  by  micrometer  adjustment,  insuring  a  constant  flame. 

Water  is  automatically  changed  from  one  receptacle  to  another  when  Tlg-  of  a 
ft.  of  gas  has  passed  through  the  meter,  entirely  obviating  the  personal  error  when 
this  is  done  by  the  operator. 

By  lightening  the  work  of  operator  he  has  time  to  determine  and  record  the 
B.T.U.  for  every  tenth  of  a  foot  burned. 

By  automatically  switching  the  water  from  one  receptacle  to  another  the  deter- 
minations are  continuous,  but  each  of  such  short  duration  that  any  accidental  derange- 
ment is  immediately  discovered. 


FIG.  225. — Collector  for  Testing  Dusty  Gases. 

By  getting  continuous  determinations  the  low  calorific  value  of  the  gas  is  ascer- 
tained at  the  same  time  as  the  total  or  high  calorific  value. 

By  making  continuous  determinations  of  the  gas  during  a  test  of  engine  or 
producer,  a  complete  record  is  secured,  even  with  a  varying  gas. 

By  plotting  the  curve  of  B.T.U.  in  the  gas  a  record  of  the  heat  value  under 
varying  conditions  of  load  and  feed  is  made. 

The  dust  and  moisture  in  blast  furnace  gas  can  be  determined  at  the  same  time  as 
the  calorific  value,  by  passing  the  gas  through  a  filter  and  dryer. 

The  percentage  of  tar  in  producer  gas  per  cubic  foot  can  be  determined  at  the 
same  time  as  the  heat  value. 

The  calorimeter  complete  is  well  made,  well  finished,  and  packed  in  an  apart- 
ment chest  for  transportation. 

The  Junker  Gas  Calorimeter. — The  increasing  use  of  gas  for  fuel  purposes  is 
making  the  heat-producing  value  of  relatively  greater  importance  than  the  candle 


HEAT  MEASUREMENTS:    PYROMETRY   AND  CALORIMETRY        449 


power  as  determined  on  photometers.  Although  the  heat  value  of  a  gas  can  be 
estimated  by  calculation  from  an  analysis,  yet  the  direct  determination,  in  an  appa- 
ratus designed  to  burn  the  gas  completely  and  collect  the  heat  in  such  a  manner  as  to 
measure  it,  is  more  rapid  and  direct.  Such  an  apparatus  is  called  a  calorimeter,  of 
whicn  the  bomb  type  is  the  most  accurate,  but  the  Junker  type  the  more  convenient 
and  most  used.  The  gas  first  passes  through  the  test-meter  provided  with  a 
thermometer  for  taking  the  temperature  of  the  gas  before  combustion,  a  pressure- 
regulator,  to  insure  constant  pressure  at  the  burner,  a  burner  removably  attached 
and  adapted  to  regulate  the  air  supply,  as  shown  by  the  detail  illustration,  a 
calorimeter  vessel  in  which  the  gas  is  burned  and  the  heat  absorbed  by  circulating 
water,  an  elevated  water  supply  flowing  under  constant  head,  and  a  vessel  for 
measuring  the  water  passing  through  it.  The  details  of  the  calorimeter  body  are 


FIG.  226. — General  Arrangement  of  Junker 
Calorimeter. 


FIG.  227. — Section  of  Pressure  Regulator  C. 


illustrated,  showing  how  the  consumed  gases  travel  up  the  combustion-chamber 
and  pass  down  through  tubes  surrounded  by  water  "and  out  into  the  air  of  the 
room  at  the  lower  opening.  The  heat  that  enters  the  apparatus  is  contained  in  the 
form  of  temperature  in  the  gas,  air,  and  water  entering  it,  and  in  combustible  con- 
stituents in  the  gas;  thermometers  are  therefore  necessary  to  test  the  temperature  of 
the  air  of  the  room,  of  the  gas  supplied,  and  of  the  water  entering  the  apparatus. 
The  heat  escaping  from  it  is  contained  in  the  products  of  combustion  (water  of  con- 
densation and  fuel-gas)  and  the  water  collected,  which  requires  two  more  thermom- 
eters. The  air-jacket  prevents  radiation  of  heat,  and  all  essential  provisions  are 
made  to  keep  heat  from  ecaping  unrecorded.  In  construction  the  apparatus  differs 
slightly  according  to  the  ideas  of  different  makers,  but  the  principles  of  operation 
remain  the  same. 

The  apparatus  being  set  up  and  properly  connected  by    rubber  tubes,  water  is 
run  into  the  elevated  tank  and  through  the  apparatus  into  the  drain  at  J  until  the 


450 


GAS   PRODUCERS 


flow  is  steady,  when  the  valve  can  be  set  with  its  indicator  on  the  scale  so  that  about 
400  cc.  of  water  will  flow  into  the  graduate  D  per  minute;  there  should  be  a  constant 
but  slight  overflow  through  the  tube  b,  which  is  regulated  by  a  valve  on  the  supply- 


Fia.  228. — Junker  Gas  Calorimeter  in  Section  and 
Elevation  and  Pressure  Regulators. 


FIG.  229.— Burner  of  Junker  Gas 
Calorimeter. 


tube  a.  The  water  level  in  the  wettest  meter  in  the  governor  and  U-tube  H  are  of  course 
looked  after  and  more  water  added  if  necessary.  Remove  the  Bunsen  burner  /,  to 
prevent  explosion,  turn  on  the  gas,  light  it,  adjust  the  air  shutter,  and  replace,  adjust- 
ing -the  gas  supply  to  keep  the  difference  in  temperature  between  ingoing  and  out- 
going water  about  10°  C.,  during  which  time  about  3  liters  of  water  are  passing. 


HEAT   MEASUREMENTS:    PYROMETRY   AND   CALORIMETRY       451 

The  rate  of  gas  flow  will  be  governed  by  the  flame,  which  should  be  of  proper  size  to 
give  out  about  1200  calories  per  hour.  Variation  in  the  quality  of  gas  therefore  will 
require  more  consumption  for  the  lean  gases  and  less  for  rich  gases,  the  latter  requir- 
ing also  a  considerable  air  supply  and  the  lean  gases  very  little,  if  any,  the  flue  damper 
being  adjusted  accordingly. 

Having  the  apparatus  in  normal  operation,  a  test  is  begun  by  taking  the  tempera- 
tures of  the  air  in  the  room  near  the  calorimeter,  the  temperature  of  the  gas  going  through 
the  meter  G,  and  the  temperature  of  the  gases  of  combustion  in  the  flue  at  J.  Then 
watch  the  meter-hand  until  it  is  at  a  convenient  starting-point,  immediately  switch 
the  outlet-tube  from  the  drain-funnel  to  the  empty  graduate,  note  the  time,  temper- 
ature of  water  entering  F  and  leaving  F'  as  quickly  as  possible  to  the  hundredth 
part  of  a  degree.  A  stop-watch  is  very  convenient  for  this  purpose,  one  that  has  a 
second  and  a  minute  hand,  and  reading-glasses  on  the  thermometers  facilitate  that 
part  of  the  work.  An  observation  is  completed  when  the  water  collected  reaches  a 
little  over  1700  cc.  in  the  graduate,  when  the  readings  are  taken  as  at  the  start,  the 
time  being  noted  when  the  outlet-tube  is  removed  from  the  graduate  and  the  meter 
read.  The  temperature  of  inlet  and  outlet  water  is  observed  about  every  half-minute. 

The  formula  for  calculating  the  calorific  value  of  a  gas  from  these  observations, 
given  in  metric  units,  is  as  follows  (see  Bates  on  "Calorimetry,"  p.  25): 

n_ 


where  C  =  calories  per  cubic  meter; 

G  —  liters  of  gas  consumed  as  shown  by  the  meter; 
TOW  ~  temperature  of  outlet  water,  thermometer  F'; 
TJW=  temperature  of  inlet  water,  thermometer  F; 

TG  =  temperature  of  the  gas  at  meter,  thermometer  G; 
TEG  =  temperature  of  escaping  gases,  thermometer  J; 

W  =  water  collected  in  graduate  D  in  liters; 

K,  K'  =  constants  calculated  from  the  specific  heats  of  the  average  quality  of  gases 
by  Bates,  as  follows,  in  calories: 

K  K' 

Natural  gas  ...........................   0.011  3.432 

Coal-gas  ...............................   0.010  2.466 

Water-gas  .............................   0.009  1  .353 

Producer-gas  ...........................   0.0089  0.470 

In  case  the  heat  value  is  desired  under  standard  conditions,  say  of  0°  C.,  where 
the  gas  is  more  dense  and  the  calorific  value  naturally  higher,  the  value  of  C  is  multi- 

Oy?  _i_  rp 

plied  by  —  ^=^  —  -.     There  is  another  correction  not  yet  mentioned  —  the  heat  carried 

—  /o 

off  by  the  moisture  condensed  from  the  water  vapor  formed  during  combustion,  which 
escapes  from  tube  No.  35  shown  in  the  section.  When  1  kilogram  of  hydrogen  burns 
to  form  9  kg.  of  water  vapor,  at  100°  C.  (212°  F.),  it  generates  28,732  calories,  but  if 


452  GAS   PRODUCERS 

this  vapor  is  brought  to  0°  C.  the  heat  given  up  is  34,462,  the  difference  being  due  to 
the  latent  heat  of  the  steam  and  in  the  water  formed.  As  calorimeter  results  may  vary 
as  much  as  10%  from  this  cause,  it  is  always  well  to  state  whether  the  calories  found  are 
gross  or  net.  The  correction  is  easy,  consisting  in  deducting  from  the  calories  found 
by  the  formula  0.636  calories  per  cubic  centimeter  of  water  of  condensation  collected; 
as  less  than  1  cc.  of  water  is  thus  collected  per  liter  of  gas,  it  is  generally  measured 
after  the  series  of  tests. 

Example.  —  In  a  5.5-minute  test  by  Bates  in  which  three  readings  were  made  on 
the  gases  and  twelve  on  the  water,  the  averages  were  found  to  be:  71G  =  25.6°,  TEG  =  2Q°, 
TJW=  14.739°,  TOTF  =  29.76°,  G  =  4.5  liters,  W=  1.74  liters.  Substituting  these  values 
in  the  formula  we  get 

n_  1.740(29.76  -14.739)  1000X0.01  (14.739  -25.6)  +2.466(20-14.739) 

~T5~ 
=  5820.985  calories  per  cubic  meter. 

Applying  now  the  temperature  correction  we  find  that  at  0°  C.  the  calorific  value  will 
be 


6 
5820.985  (  -    .        -  |  =  6344.8736  calories. 


'To  reduce  this  to  B.T.U.  per  cu.ft.  multiply  by  0.11236,  thus: 

6344.8736X0.11236  =  712.9099  B.T.U. 

Doherty  Gas  Calorimeter.—  The  gas  under  test  is  completely  burned  in  a  Bunsen 
burner,  and  the  entire  quantity  of  heat  liberated  by  this  combustion  is  transmitted 
to  or  absorbed  by  water  which  is  constantly  kept  flowing  through  a  boiler,  preferably 
called  an  absorption-chamber.  The  temperature  of  the  water  before  entering  and 
after  leaving  the  absorption-chamber  is  taken,  and  the  water  after  leaving  the  absorp- 
tion-chamber passes  to  a  tank  which  contains  the  gas  before  it  is  burned.  Thus  the 
water  displaces  the  gas  volume  for  volume.  Consequently  for  each  cubic  foot  of  gas 
burned  there  passes  through  the  absorption-chamber  a  cubic  foot  of  water,  so  that 
there  is  a  constant  ratio  between  the  amount  of  gas  burned  and  the  amount  of  water 
passed  through  the  absorption-chamber.  As  the  difference  in  temperature  of  the 
water  is  taken  before  and  after  passing  through  the  absorption-chamber,  there  is 
afforded  a  means  for  measuring  the  amount  of  heat  generated  by  the  burning  of  the 
gas  —  that  is,  the  difference  in  reading  of  the  inlet  and  outlet  thermometers  in  degrees 
Fahrenheit,  multiplied  by  the  coefficient  of  thermal  capacity  of  a  cubic  foot  of  water, 
gives  the  calorific  value  of  a  cubic  foot  of  gas  in  British  thermal  units.  The  temper- 
ature of  the  gas  under  test  is  brought  to  that  of  the  room  by  allowing  the  gas  to 
remain  in  a  tank  until  it  acquires  the  room  temperature.  The  waste  products  of 
combustion  are  allowed  to  escape  from  the  absorption-chamber  at  a  temperature 
equal  to  that  of  the  room.  Consequently  the  only  heat  given  to  the  water  passing 
through  the  absorption-chamber  is  the  heat  due  to  the  combustion  of  the  gas.  The 


HEAT  MEASUREMENTS:    PYROMETRY   AND  CALORDIETRY        453 

temperature  of  the  waste  gases  is  controlled  by  varying  the  amount  of  exposed  cooling- 
surfaces  of  the  absorption-chamber.  Therefore  as  the  gas  in  the  tank  is  maintained 
under  a  constant  pressure  and  the  water  from  the  absorption-chamber  passes  into 
the  tank  with  a  speed  equal  to  that  of  the  gas  flowing  out  and  to  the  Bunsen  burner, 
there  is  afforded  a  means  for  accurately  determining  the  calorific  value  of  the  gas 
without  making  corrections  for  difference  in  temperature  of  the  gas  before  and  after 


FIG.  230.— The  Doherty  Gas  Calorimeter. 

combustion;  nor  is  it  necessary  to  make  corrections  due  to  difference  in  temperature 
of  both  the  air  required  to  support  combustion  and  the  products  of  combustion. 
Under  the  conditions  that  water  is  flowing  into  the  tank  as  fast  as  the  gas  is  flowing  out, 
and  the  gas  is  flowing  to  the  Bunsen  burner  through  a  constant  orifice  and  under 
constant  pressure,  it  is  required  that  water  should  pass  through  the  absorption-chamber 
at  a  constant  rate,  which  reduces  to  zero  any  error  that  might  occur  due  to  the  absorp- 
tion-chamber having  a  high  thermal  capacity  on  account  of  its  own  mass  and  the  mass 
of  water  it  contains,  provided  the  temperature  of  the  water  at  intake  remains  constant, 
which  is  the  usual  condition  in  practice. 


454 


GAS   PRODUCERS 


The  Lucke- Junkers  Gas  Calorimeter. — Dr.  Chas.  E.  Lucke  of  Columbia  University, 
has  converted  a  Junkers  calorimeter  into  one  of  the  recording  or  continuous  type  by 
the  addition  of  a  displacement  tank,  the  air  and  gas  successively  displacing  one 
another. 


FlG.  231. — The  Lucke  Continuous  Record  Gas  Calorimeter. 

Parr  Coal  Calorimeter. — The  accompanying  illustration  shows  the  relative 
position  of  parts.  The  can  A  is  filled  with  two  liters  of  water.  The  combustion  takes 
place  within  the  cartridge  D.  The  resulting  heat  is  imparted  to  the  water.  The  rise 
in  temperature  is  indicated  by  the  finely  graduated  thermometer  T. 

Description. — The  facility  of  operation  may  be  shown  by  a  brief  description  of 
the  apparatus.  In  the  cartridge  is  placed  a  weighted  quantity  of  coal  previously 
ground  to  pass  through  a  100  mesh  sieve  and  dried  in  the  usual  way  at  105-100°  C. 
(220-230°  F.).  There  is  also  put  into  the  cartridge  a  chemical  compound  which  is 
thoroughly  mixed  with  the  coal  by  shaking.  The  cartridge  is  then  placed  in  a  measured 
quantity  of  water  in  the  insulated  calorimeter  can  A  as  shown.  The  stirrer  is  set  in 
motion,  operated  by  a  cord  about  the  pulley  P.  After  a  constant  temperature  has 
been  obtained,  ignition  is  effected  by  means  of  a  short  piece  of  hot  wire  dropped 
through  the  stem  of  the  cartridge.  Extraction  of  the  heat  is  complete  in  from  four  to 
five  minutes.  The  maximuum  reading  is  taken  and  the  rise  in  temperature,  multipled 
by  a  simple  factor,  gives  the  heat  in  British  thermal  units  per  pound  of  coal.  By  a 


HEAT   MEASUREMENTS:    PYROMETRY    AND   CALORIMETRY        455 

slight  modification  of  the  apparatus  ignition  may  also  be  effected  by  an  electric  fuse, 
and  where  a  proper  current  is  available,  this  method  is  preferred  by  some  users.  Electric 
ignition  is  effected  by  means  of  the  fuse  wire  G  connecting  the  terminals  H  and  /.  This 
wire  is  of  about  34  American  gauge  and  approximately  4  ins.  in  length.  The  loop 
extends  about  three-fourths  of  an  inch  below  the  terminals  and  well  into  the  chemical 
mixture.  By  making  contact  with  a  suitable  current  of  electricity  between  the  outer 


FIG.  232.— Section  of  Parr  Coal 
Calorimeter. 


FIG.  233.— Cartridge  Ignited 
by  Hot  Wire. 


FIG.    234.  — Cartridge 
Electrically  Ignited. 


terminal  K  and  the  metal  of  the  stem  B,  the  filament  of  wire  G  is  brought  quickly  to 
a  red  heat,  thus  igniting  the  charge.  The  current  required  is  from  2  to  4  amperes, 
and  is  readily  obtained  by  placing  in  parallel  4  to  8  16-candle  power  lamps  in  an 
ordinary  lighting  circuit  of  110  volts  as  shown. 

Directions. — The  calorimeter  should  be  placed  on  a  good  firm  desk  or  table.  The 
power  needed  is  exceedingly  slight;  the  smallest  possible  electric  or  water  motor  being 
ample.  Revolve  the  pulley  by  means  of  a  loose  cord  at  the  rate  of  about  100  revolu- 
tions per  minute. 


456 


GAS   PRODUCERS 


The  parts  chould  be  removed  from  the  instrument  for  filling  with  water  and  care 
observed  that  no  water  remains  on  the  outside  or  is  allowed  to  spill  over  into  the  air 
•spaces  of  the  insulating  vessels.  Exactly  two  liters  of  water  (preferably  distilled)  are 
used  and  it  should  have  a  temperature  of  about  3°  F.  below  the  temperature  of  the 
room.  That  is,  approximately  three-fourths  of  the  total  rise  in  temperature  should 
occur  before  the  temperature  of  the  room  is  reached. 


FIG.  235. — Parr  Calorimeter,  Complete. 

The  glass  jar  is  for  the  chemical  that  should  be  kept  carefully  closed  and  clamped 
to  prevent  absorption  of  moisture  from  the  air.  For  this  reason  also,  only  the  contents 
of  one  small  can  of  chemical  is  emptied  into  the  jar  at  one  time.  There  will  also  be  left 
room  for  the  measuring  cup  and  handle  complete. 


FIG.  236. — Resistance  for  Electric  Circuit. 

To  prepare  the  cartridge  for  filling,  dry  all  the  parts  perfectly  inside  and  out; 
see  that  the  inner  bottom  C  with  gasket  is  properly  seated,  screw  on  the  outer  bell  E, 
then  with  the  spanner  wrench  screw  up  firmly  the  outer  bottom  D  and  place  on  a  sheet 
of  white  paper.  The  coal  is  prepared  by  grinding  in  a  mortar  and  passing  through  the 
seive  of  100  meshes  to  the  inch.  Coals  containing  over  2J  or  3%  of  water  should  have 
the  water  removed.  In  such  cases  the  exact  charge  of  the  commercially  dry  coal  is 


MEAT  MEASUREMENTS:    PYROMETRY    AND  CALORIMETRY        457 

weighed  out  and  dried  for  an  hour  at  105-110°  C.  (220-230°  F.)  then  transferred  to 
the  cartridge. 

One  of  the  cartridges  represents  the  new  style  of  bomb  with  electric  method  of 
ignition.  A  differently  devised  stem  B  for  ignition  by  dropping  a  red  hot  wire  into 
the  charge  may  also  be  used  if  desired. 

Operation. — The  following  procedure  is  employed  for  all  ordinary  bituminous  and 
semi-bituminuos  coals,  lignites,  etc.  Exactly  one-half  gram  of  coal  is  taken  and  dried 
as  above  indicated.  This  is  added  to  the  cartridge  which  has  been  thoroughly  dried 
and  prepared. 

Add  exactly  one-half  gram  of  the  "  boro-mixture  "  and  finally  one  full  measure 
of  the  ordinary  chemical  (sodium  peroxide).  Tap  the  measure  against  the  side  of 
the  jar  to  insure  filling  completely  and  expose  this  material  to  the  air  the  shortest 
time  possible. 

The  stem  and  top  B  with  the  terminals  HI  having  a  loop  of  fine  wire  G  extending 
about  an  inch  below,  are  put  in  position  and  the  cap  F  screwed  firmly  in  place.  The 
loop  of  fine  wire  should  be  long  enough  to  extend  into  the  mixture.  Where  the  spring 
valve  and  hot  wire  method  of  ignition  is  used  the  procedure  is  not  essentially  different. 

Shake  vigorously  to  thoroughly  mix  the  contents.  When  the  mixing  is  com- 
plete tap  the  cartridge  lightly  to  settle  the  contents  and  to  mix  all  the  material 
from  the  upper  part  of  the  cylinder.  Put  on  the  spring  clips  with  vanes.  The 
cartridge  is  now  put  in  place,  the  can  with  water  being  already  in  position.  Adjust 
the  cover.  Insert  the  thermometer  so  that  the  lower  end  of  the  bulb  will  be  about 
midway  towards  the  bottom  of  the  can,  place  the  pulley  on  the  stem  and  connect 
with  the  motor.  The  cartridge  should  turn  to  the  right,  or  as  the  hands  of  a  watch, 
thus  deflecting  the  current  downward.  After  about  three  minutes  the  first  read- 
ing of  the  thermometer  may  be  taken. 

Ignition  by  the  electric  method  is  effected  by  closing  the  circuit  which  brings 
the  loop  G  of  fine  wire  to  the  red  heat,  thus  igniting  the  charge.  In  the  hot  wire 
method,  ignite  with  the  short  piece  of  soft  iron  wire  which  is  held  or  rests  on  a  wire 
gauze  in  a  Bunsen  flame  until  red  hot;  drop  quickly  into  the  opening  at  the  upper 
end  of  the  valve,  allowing  the  wire  to  lodge  at  the  lower  end  before  being  admitted. 
With  the  pincers  the  valve  is  now  pressed  completely  down  and  released  with  a 
quick  movement  so  as  to  prevent  the  escape  of  heated  air  from  the  interior. 

All  the  time  of  course  the  revolving  of  the  cartridge  continues.  The  combus- 
tion should  be  indicated  by  a  rapid  rise  of  the  mercury,  which  reaches  its  maximum 
height  after  from  four  to  five  minutes.  Make  note  of  the  final  temperature  and 
compute  thus: 

Calculation. — Subtract  the  correction  factor  for  the  heat  of  the  wire  and  chem- 
ical, as  indicated  on  the  small  bottle  of  borate  mixture.  Multiply  the  remainder  by 
3117.  The  product  will  be  the  number  of  B.T.U.'s  per  pound  of  coal.  (See  notes 
a  and  b.) 

To  dismantle  remove  the  thermometer,  pulley,  and  cover;  then  take  out  the 
can  and  contents  entire,  so  that  the  lifting  out  of  the  cartridge  will  not  drip  water 
into  the  dry  parts  of  the  instrument.  Remove  the  spring  clips  and  unscrew  the 
ends.  It  is  better  to  loosen  the  bottom  D,  and  unscrew  the  entire  bell  E  for  cleaning. 
The  fused  mass  is  easily  driven  out  at  the  bottom  by  aid  of  a  short  metal  rod.  The 


458  GAS   PRODUCERS 

cartridge  and  ends  are  rinsed  clean  and  at  once  thoroughly  dried,  when  they  will 
be  ready  for  a  new  test.  It  is  a  good  plan  to  place  the  end  with  the  electric  ter- 
minals in  boiling  water  for  a  short  time.  This  facilitates  drying  and  cleans  off  any 
chemical  from  the  face  that  might  cause  short-circuiting. 

For  all  Anthracite,  Cokes,  etc.,  grind  and  sift  the  coal  as  usual.  Weigh  out 
exactly  one-half  gram  for  the  test;  drying  may  be  omitted  if  the  water  content  is 
below  2i  or  3%.  Transfer  the  sample  to  the  cartridge  and  add  exactly  1  gram  of  the 
boro-mixture  for  anthracites,  petroleums,  etc.,  Then  add  one  measure  of  the  ord- 
inary chemical  (sodium  peroxide).  Shake  thoroughly  and  place  in  the  can,  assemble 
and  complete  the  combustion  in  the  usual  manner. 

Calculation. — The  correction  factor  for  the  extra  chemical  and  fine  wire  is 
marked  on  the  label,  but  twice  the  correction  should  be  made  where  1  gram  is  u^ed, 
excepting  that  to  double  this  factor  would  be  to  count  the  correction  for  the  wire 
twice,  since  its  value  is  included  in  the  correction  marked  on  the  label  for  \  gram. 
The  wire  values  alone  are  as  follows: 

By  electric  method 0.011  deg.  F. 

By  hot  wire  method 0.022  deg.  F. 

Hence  twice  the  indicated  factor  for  one  half  gram,  minus  twice  the  wire  value, 
as  indicated  above  would  be  the  correction  factor  for  one  gram  of  the  boro-mixture. 
Subtract  this  number  from  the  total  rise  in  temperature  and  compute  thus;  multiply 
the  remainder  by  3117.  The  product  will  be  the  B.T.U.  per  pound  of  coal.  (See 
notes  a  and  6.) 

Notes. — (a)  The  factor  3117  is  deduced  as  follows:  The  wrater  used  plus  the 
water  equivalent  of  the  water  in  the  metal  in  the  instrument  amounts  to  2135  grains, 
In  the  reaction  73%  of  the  heat  is  due  to  combustion  of  the  coal,  and  27%  is  due  to  heat 
of  combustion  of  CC>2  and  H2O  with  the  chemical.  If  now  one-half  gram  of  coal 
causes  2135  grams  of  water  to  rise  R  degrees,  and  if  only  73%  of  this  is  due  to  com- 
bustion, then  0.73X2135X2X^  =  rise  in  temperature  that  would  result  from  com- 
bustion of  an  equal  weight  (2135  grams  of  coal: 0.73X2135X2  =  31 17. 

(6)  With  the  electric  method  of  ignition  the  fine  wire  is  wrapped  firmly,  and 
with  good  contact  around  the  ends  of  the  terminals,  and  bent  U-shaped  so  as  to 
extend  below  about  an  inch.  Do  not  have  too  great  a  length  of  free  wire  for  the 
current.  Make  a  preliminary  test  with  the  stem  free  so  the  action  can  be  seen.  The 
wire  should  quickly  become  red  hot.  The  amount  of  wire  burned  varies  slightly, 
but  ordinarily  amounts  to  about  0.008  gram.  If  extreme  accuracy  is  desired,  the 
weight  of  wire  consumed  most  easily  determined  by  measurement,  multiplied  by 
the  calorific  value  of  iron'  (1600),  and  divided  by  the  water  equivalent  of  the  appara- 
tus, will  give  the  rise  in  centigrade  degrees  due  to  the  combustion  of  the  iron,  approx- 
imating on  the  average  very  closely  to  0.011°  F.  In  the  other  method  of  starting 
the  combustion,  the  ignition  wire  is  of  soft  iron,  2^  mm.  in  diameter  or  No  11  gauge 
and  1  cm.  long,  it  should  weigh  approximately  0.33  gram.  It  loses  a  very  little 
by  use.  When  by  oxidation  the  weight  falls  very  much  below  0.3  gram  a  new  wire 
should  be  substituted.  The  correction  for  the  hot  wire  may  be  calculated  thus; 


HEAT  MEASUREMENTS:    PYROMETRY   AND  CALORIMETRY        459 

Taking  0.114  as  the  specific  heat  and   1200-1300°  F.  as  the  temperature  at  a  red 
heat,  then 

1250X0.330X0.114 


2135 


=  0.022. 


Hence  the  value  of  the  hot  wire  approximates  closely  to  0.022°  F. 

(c)  It   is   imperative   that   the   sodium   peroxide   be    kept    securely  sealed   from 
contact   with   the  air.     The   chemical  supplied   with   the  apparatus  is  of  a   superior 
grade  prepared  especially  for  this  work,  and  is  practically  free  from  sodium  carbonate. 

(d)  Do  not  bring  the  instrument  from  a  cold  room  to  work  at  once  in  a  warm 
room  or  vice  versa.     An  hour  at  least  should   be  given   for  equalization  of   tempera- 
tures.    Dry  the   bomb   thoroughly  inside  before  putting  away.     Dry  it  before  using, 
if  it  has  stood  for  some  time,  as  moisture  condenses  on  the  inside. 

(e)  Do  not  throw  a  mixture  of  chemical  and  unburned  coal  into  water.     It  may 
ignite  violently.      Similarly  a  drop  of  water  left  inside  the  valve  may  work  into  the 
charge  during  the  shaking  and  ignite  it  prematurely. 

(/)  It  is  well  to  test  the  action  of  the  valve  by  dropping  the  wire  through  on  to 
a  sheet  of  paper  a  number  of  times,  holding  the  stem  in  the  hand  and  dropping  the 
wire  as  in  igniting  a  charge.  It  will  be  noted  that  the  wire  is  allowed  to  lodge  at 
the  valve,  then  is  released  by  pressure  at  the  top.  Too  sudden  a  pressure  and  release 
or  a  failure  to  press  the  valve  completely  down,  may  result  in  catching  the  wire 
before  it  has  cleared  the  valve.  In  such  a  case  of  course  the  charge  would  fail  of 
ignition. 

(y)  The  above  directions-  presume  the  use  of  a  Fahrenheit  thermometer.  In 
case  a  centigrade  thermometer  is  used,  the  use  of  the  factor  3117  gives  the  result  in 
kilocalories.  To  change  kilocalories  to  B.T.U.,  multiply  by  1.8.  Also  the  correc- 
tion factors  as  given  on  the  special  borate  mixtures  should  be  divided  by  1.8. 

(h)  It  is  to  be  recommended,  especially  where  room  temperatures  are  not 
easily  controlled,  and  in  all  cases  where  extreme  accuracy  is  desired,  that  a  correction 
for  radiation  be  introduced.  An  adaption  of  Newton's  law  is  well  suited  to  the  con- 
ditions as  follows:  Read  the  fall  in  temperature  for  the  second,  third,  and  fourth 
minutes  after  the  maximum  has  been  reached.  The  average  drop  per  minute  repre- 
sents the  correction  to  be  added  to  each  minute  preceding  the  maximum,  except  for 
the  minute  immediately  following  ignition. 

Tap  the  thermometer  lightly  to  settle  the  mercury  column  before  each  reading. 

Total  Carbon  Apparatus. — The  residue  from  the  determination  of  the  heat 
values  has  the  carbon  of  the  coal  combined  in  the  form  of  sodium  carbonate.  By 
adding  acid  to  the  dissolved  material  in  a  suitable  apparatus,  and  liberating  the 
carbon  dioxide  gas  under  conditions  which  make  it  available  for  measurement,  we 
have  a  ready  method  for  determining  the  volume  of  the  C02.  From  this  reading, 
in  conjunction  with  the  temperature  and  barometric  pressure,  we  may  calculate 
the  weight  of  the  carbon  orginally  present  in  the  coal.  This  is  a  factor  not  heretofore 
available  except  by  ultimate  analysis. 

The  fused  material  is  brought  into  the  flask  B  and  dissolved  with  the  washings 
from  the  interior  of  the  bomb.  By  admitting  acid  from  a  funnel  A,  the  carbon  dioxide 
is  liberated  and  carried  over  into  a  jacketed  burette  G.  In  this  condition  also,  the 


460 


GAS   PRODUCERS 


temperature  may  be  read  by  means  of  the  thermometer  suspended  in  the  water 
surrounding  the  burette.  The  gas  thus  measured,  which  may  also  have  a  small 
admixture  of  air,  is  conducted  over  into  an  absorption  bulb  P,  in  which  is  contained 
a  solution  of  caustic  potash,  for  absorbing  the  CO2.  Upon  returning  the  residual 
gas  to  the  burette  G  and  reading  the  volume,  the  diminution  indicates  the 
volume  of  carbon  dioxide  present  at  the  outset.  The  apparatus  permits  of  boiling 


D-O 


FIG.  237. — Total  Carbon  Apparatus  for 
Parr  Test. 


FIG.  238.- 


-Sulphur  Determination  Apparatus 
for  Parr  Test. 


the  liquid  in  the  flask  B  in  order  to  expel  the  dissolved  gases  and,  by  means  of  the 
condenser,  the  gas  is  maintained  at  a  constant  temperature. 

Moisture — For  all  practical  purposes  dry  one  gram  of  coal  in  an  open  crucible 
at  220  to  225°  F.,  the  amount  of  distillation  will  fairly  reflect  the  moisture  content. 
This  method  is  of  course  only  approximately  accurate,  in  connection  with  the  use 
of  analytical  balances  sensative  to  milligrams. 

Another  method  is  given  by  A.  H.  Gill,  in  his  "Engine  Room  Chemistry,"  and  is 
as  follows:  Procure  a  pair  of  three-inch  watch  glasses,  the  edges  of  which  are  ground 
to  fit  accurately  together,  and  which  are  held  together  by  a  watch-glass  clip.  Weigh 


HEAT  MEASUREMENTS:    PYROMETRY  AND  CALORIMETRY        461 

out  about  five  grams  of  the  coal  from  the  test  tube  mentioned  above  between  these 
glasses  using  the  horn  pan  balances. 

Remove  the  clip,  open  the  glasses  and  place  them  in  the  oven  at  220  to  225°  F. 
(104  to  107°  C)  for  one  hour;  remove  them  from  the  oven,  replace  the  clip,  cool  under 
a  bell  jar  and  weigh  when  cold.  The  loss  of  weight  represents  the  moisture  in  the 
coal  and  should  be  expressed  in  per  cent. 

Sulphur  Photometer. — -The  fusion  of  coal,  coke,  petroleum,  etc.,  by  means  of 
sodium  peroxide,  as  carried  out  in  the  Parr  calorimeter,  is  made  use  of  for  determin- 
ing sulphur.  Upon  removal  of  the  fused  mass,  it  is  dissolved  in  water  and  made 
slightly  acid  with  pure  hydrochloric  acid.  An  aliquot  part  of  this  solution  is  taken 
and  made  up  to  100  cc.  and  transferred  to  an  Erlenmeyer  flask.  To  this,  at  room 
temperature,  is  added  a  large  crystal  of  barium  chloride,  and  at  once  the  flask  is 
shaken  vigorously  for  a  short  time.  The  turbid  solution  is  then  ready  to  read  in 
the  photometer.  The  liquid  containing  the  finely  divided  precipitate  of  barium 
sulphate,  is  poured  into  the  dropping  funnel  F,  and  gradually  admitted  through  the 
pinch-cock  C  into  the  graduated  tube  .4.  The  lens  effect  at  the  bottom  of  the  tube 
is  obtained  by  immersing  the  same  in  water,  as  shown  in  B.  By  noting  the  depth 
at  which  the  light  from  the  flame  disappears  a  reading  is  obtained  directly,  which 
indicates  the  percentage  of  sulphur  in  the  sample  under  examination.  The  accuracy 
of  results  so  obtained  is  close  enough  for  practical  purposes. 


CHAPTER  XX 
PIPES,    FLUES,   AND   CHIMNEYS 

CAPACITY  OF  PIPES 

Flow  of  Gases  in  Pipes.— The  following  notes  upon  Dr.  Pole's  formula  for  the 
flow  of  gases  in  pipes  have  been  made  by  F.  S.  Cripps  and  published  in  the  Journal 
of  Gas  Lighting.  Let 

Q  =  discharge  of  gas  in  cubic  feet  per  hour; 
d  =  diameter  of  pipe  in  inches; 
p  =  pressure  of  gas  in  inches  of  water; 
s  =  specific  gravity  of  gas,  air  equalling  1; 
/  =  length  of  pipe  in  yards. 


Q2sl 
P 


7_(1350)2d5?? 
Q2s       ' 


s  =  - 

y-f 

462 


PIPES,  FLUES,  AND  CHIMNEYS  463 

From  the  above  it  is  apparent  that,   other  things  being  equal, 


Q  varies  directly  as     Vp 


I 

"        inversely  as  V7 

inversely  as  d5 

I  varies  directly  as    p 
.d  varies  directly  as 


\/T 


p  varies  directly  as    Q2 


inversely  as  Q2 


inversely  as  Vp  *  varies  directly  as    p 

d5 

inversely  as  Q2 
"  "  I 


A  consideration  of  the  foregoing  gives  rise  to  the  following  axioms  or  rules : 

Quantity — Pressure. — Double  the  quantity  requires  four  times  the  pressure. 

Or,  four  times  the  pressure  will  pass  double  the  quantity. 

Half  the  quantity  requires  one-fourth  the  pressure. 

Or,  one-fourth  the  pressure  is  sufficient  for  half  the  quantity. 

Quantity — Length. — Double  the  quantity  can  be  discharged  through  one-fourth 
the  length. 

Or,  one-fourth  the  length  will  allow  of  double  the  discharge. 

Half  the  quantity  can  be  discharged  through  four  times  the  length. 

Or,  four  times  the  length  reduces  the  discharge  one-half. 

Quantity — Diameter. — Thirty-two  times  the  quantity  requires  a  pipe  four  times 
the  diameter. 

Or,  a  pipe  four  times  the  diameter  will  pass  thirty-two  times  as  much  gas. 

A  pipe  one-fourth  the  diameter  will  pass  one  thirty-second  of  the  quantity. 

Or,  one  thirty-second  of  the  quantity  can  be  passed  by  a  pipe  one-fourth  the 
diameter. 

Quantity — Specific  Gravity. — The  specific  gravity  stands  in  just  the  same  relation 
to  the  volume  as  the  length  does  (see  Axioms  3  and  4). 

Pressure — Length. — If  the  pressure  is  doubled  the  length  may  be  doubled. 

And,  conversely,  if  the  length  be  doubled  the  pressure  must  be  doubled. 

If  the  pressure  be  halved  the  length  may  be  halved. 

And,  conversely,  if  the  length  be  halved  the  pressure  must  be  halved. 

From  Axioms  8  and  9  it  is  evident  that — 

The  pressure  required  to  pass  a  given  quantity  of  gas  varies  exactly  as  the 
length  of  the  pipe. 

Pressure — Specific  Gravity. — The  pressure  required  to  pass  a  given  quantity  of 
gas  also  varies  exactly  as  the  specific  gravity  of  the  gas.  Hence  if  the  specific  gravity 
of  the  gas  were  doubled,  double  the  pressure  would  be  required. 


464  GAS   PRODUCERS 

Pressure — Diameter. — One  thirty-second  part  of  the  pressure  is  sufficient  if  the 
diameter  be  doubled;  or,  in  other  words,  if  you  double  the  diameter  you  require  only 
one  thirty-second  of  the  pressure  to  pass  the  same  quantity  of  gas. 

If  you  halve  the  diameter,  thirty-two  times  the  pressure  is  required. 

And,  conversely,  if  you  increase  the  pressure  thirty-two  times,  the  diameter  can 
be  halved. 

Length — Diameter. — The  length  can  be  increased  thirty-two  times  if  the  diameter 
be  doubled. 

And,  conversely,  if  the  diameter  be  doubled,  the  length  can  be  increased  thirty- 
two  times  and  pass  the  same  quantity  of  gas. 

If  the  diameter  be  halved,  the  length  must  be  reduced  to  one  thirty-second  to 
pass  the  same  quantity  of  gas. 

And,  conversely,  if  the  length  be  made  one  thirty-second  of  the  distance,  the 
diameter  may  be  halved. 

Specific  Gravity — Length. — If  the  specific  gravity  be  doubled,  the  length  must  be 
halved,  and  vice  versa,  to  satisfy  the  equation. 

Specific  Gravity — Diameter. — The  specific  gravity  follows  the  same  laws  as  the 
length  does  in  relation  to  the  diameter. 

It  must  be  borne  in  mind,  when  using  the  above  rules,  that  all  other  conditions 
remain  the  same  when  considering  the  effect  of  one  factor  on  another  in  the  different 
pairs. 

The  above  may  be  found  convenient  for  rule-of-thumb  calculations. 

Comparison  of  Formula. — Mr.  Oliphant  has  checked  certain  formula  on  deliver- 
ing natural  gas  100  miles  into  a  gas-holder  through  8-inch  pipe. 

Taking  the  same  conditions  and  using  the  several  formula1,  we  obtain  the 
following  results: 

Formula.  Calculated  Cu.ft.  per  Hour. 

Actual  volume  delivered 18,200 

Pittsburg 18,380 

Cox's 16,000 

Oliphant's 16.260 

Oliphant's,  corrected 17,510 

Robinson's 18,730 

Unwin's 31,870 

Velde's 22,060 

Richard's  (corrected  for  O.Q-g  gas) 18,708 

Hiscox's  (corrected  for  0.6-0  gas) 16,250 

Lowe's 26,910 

Piping. — The  gas-range  having  4  top  burners  and  an  oven-burner  should  never 
be  connected  to  the  meter  by  less  than  a  ^-in.  pipe  and  this  should  only  be  in  instances 
where  the  run  is  50  ft.  or  under,  1-in.  pipe  being  used  for  a  greater  distance.  This 
calculation,  based  on  gas  having  a  specific  gravity  of  0.7,  would  show  a  loss  in  pres- 
sure of  about  0.1  in.,  which,  under  average  conditions  should  be  the  maximum  loss 
advisable. 


PIPES,  FLUES,  AND  CHIMNEYS 


465 


FLOW    OF   GAS    IN   CUBIC   FEET   PER    HOUR   THROUGH   THIN   ORIFICES,    SUCH   AS 

AIR-MIXERS,   FOR  GAS-STOVES 


Pressure  Equivalents. 

Diameter  of  Orifices,  Inches. 

Ounces 
per 
Square  Inch. 

Tenths  of 
Inches  of 
Water  Head. 

Tenths  of 
Inches  of 
Mercury 
Column. 

A             A 

£ 

A 

& 

_8_ 
32 

Cubic  Feet  Discharged  per  Hour. 

8 

0.59 

8.0 

12.0 

15 

20 

30 

45 

10 

0.74 

9.0 

13.0 

17 

23 

34 

51 

12 

0.89 

10.0 

15.0 

18 

25 

36 

56 

0.8 

13.6 

1.00 

10.8 

16.0 

20 

27 

40 

61 

14 

1.03 

11.3 

17.0 

21 

28 

42 

63 

16 

1.18 

11.6 

17.5 

21 

29 

43 

65 

18 

1.34 

12.0 

18.0 

22 

30 

44 

67 

20 

1.48 

12.8 

19.0 

23 

32 

46 

72 

25 

1.86 

13.5 

20.4 

25 

34 

50 

76 

1.6 

27 

2.00 

15.9 

21.0 

27 

38 

54 

86 

1.8 

30 

2.02 

16.4 

24.5 

31 

41 

62 

92 

2.4 

41 

3 

18.0 

27.5 

34 

46 

68 

105 

3.2 

54 

4 

21.6 

32.0 

41 

54 

82 

122 

4.0 

68 

5 

24.0 

35.5 

46 

60 

92 

135 

4.8 

81 

6 

26.4 

39.5 

51 

66 

102 

148 

5.6 

65 

7 

28.4 

42.5 

54 

71 

108 

160 

6.4 

109 

8 

30.0 

45.0 

57 

75 

114 

169 

7.2 

122 

9 

31.0 

47.0 

61 

78 

122 

176 

8.0 

137 

10 

32.4 

48.5 

64 

81 

128 

182 

8.8 

150 

11 

33.0 

51.0 

68 

85 

138 

191 

9.6 

163 

12 

37.2 

55.0 

71 

93 

142 

209 

10.4 

177 

13 

38.8 

58.0 

74 

97 

148 

218 

11.2 

190 

14 

40.4 

60.5 

77 

101 

154 

227 

12.0 

204 

15 

42.0 

63.0 

80 

105 

160 

236 

12.8 

218 

16 

43.0 

65.0 

82 

108 

164 

243 

13.6 

231 

17 

44.0 

66.0 

84 

110 

168 

247 

14.4 

245 

18 

45.6 

67.0 

87 

114 

174 

255 

15.2 

258 

19 

47.0 

70.0 

90 

117 

180 

263 

16.0 

274 

20 

48.0 

72.0 

92 

120 

184 

270 

SIZES   OF   PIPE  REQUIRED  FOR  CITY  GAS 
(Allow  three-tenths  drop  in  pressure.     Add  10  ft.  to  length  of  pipe  for  each  elbow) 


Cubic  Feet  Gas 
per  Hour. 

Length  of  Pipe, 
Feet. 

Size  of  Pipe 
Required. 

Cubic  Feet  Gas 
per  Hour. 

Length  of  Pipe, 
Feet. 

Size  of  Pipe 
Required. 

25 

0  to  190 

£  inch 

200 

100  to  300 

1^  inch 

25 

190  to  500 

J     " 

250 

0  to    50 

1 

50 

0  to  100 

*     " 

250 

50  to  200 

H 

50 

100  to  375 

*     " 

250 

200  to  525 

11 

75 

0  to    25 

i    " 

300 

Oto    25 

1 

75 

25  to  150 

f    " 

300 

25  to  100 

H 

75 

150  to  450 

1     " 

.300 

100  to  375 

« 

100 

0  to  100 

*    " 

400 

Oto    75 

H 

100 

100  to  375 

i     " 

400 

75  to  150 

« 

150 

Oto    25 

i   " 

400 

150  to  758 

2 

150 

25  to  200 

i     " 

500 

Oto    25 

H 

150 

200  to  600 

H   " 

500 

25  to  100 

H 

200 

Oto  100 

i     " 

500 

100  to  525 

2 

466 


GAS    PRODUCERS 


A  quick  graphical  method  of  finding  the  diameter  of  branch  pipes  leading  from 
mains  is  to  lay  off  on  a  straight  line  the  diameter  of  the  main  to  any  scale  desired. 
From  its  center  draw  a  semi-circle  to  the  ends  and  erect  a  perpendicular  from  the  center. 
Now  join  the  ends  of  the  diameter  with  the  top  of  this  perpendicular  and  they  will 
equal  the  diameter  of  the  branch,  as  shown  in  the  diagram. 


FIG.  239. — Relation  of  Mains  to  Branches. 


COMPARATIVE  CAPACITY   OF   PIPES  OF   DIAMETERS  GIVEN 


l! 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

12 

14 

16 

18 

20 

24 

2 
3 

5.7 
15.6 

1 

2.8 

1 

4 

32 

5.7 

2.1 

1 

5 

55.9 

9.9 

3.6 

1.7 

1 

6 

88.2 

15.6 

5.7 

2.8 

1.6 

1 

7 

130 

22.9 

8.3 

4.1 

2.3 

1.5 

1 

8 

181 

32 

11.7 

5.7 

3.2 

2.1 

1.4 

1 

9 

243 

43 

15.6 

7.6 

4.3 

2.8 

1.9 

1.3 

1 

10 

316 

55.9 

20.3 

9.9 

5.7 

3.6 

2.4 

1.7 

1.3 

1 

11 

401 

70.9 

25.7 

12.5 

7.2 

4.6 

3.1 

2.2 

1.7 

1.3 

12 

499 

88.2 

32 

15.6 

8.9 

5.7 

3.8 

2.8 

2.1 

1.6 

1 

13 

609 

108 

39.1 

19 

10.9 

7.1 

4.7 

3.4 

2.5 

1.9 

1.2 

14 

733 

130 

47 

22.9 

13.1 

8.3 

5.7 

4.1 

30 

2.3 

1.5 

1 

15 

787 

154 

55.9 

27.2 

15.6 

9.9 

6.7 

4.8 

3.6 

2.8 

1.7 

1.2 

16 

181 

65.7 

32 

18.3 

11.7 

7.9 

5.7 

4.2 

3.2 

2.1 

1.4 

1 

17 

211 

76.4 

37.2 

21.3 

13.5 

9.2 

6.6 

4.9 

3.8 

2.4 

1.6 

1.2 

18 

243 

88.2 

43 

24.6 

15.6 

10.6 

7.6 

5  7 

4.3 

2.8 

1.9 

1.3 

1 

19 

278 

101 

49.1 

28.1 

17.8 

12.1 

8.7 

6.5 

5 

3.2 

2.1 

1.5 

1.1 

20 

316 

115 

55.9 

32 

20.3 

13.8 

9.9 

7.4 

5.7 

3.6 

2.4 

1.7 

1.3 

1 

22 

401 

146 

70.9 

40.6 

25.7 

17.5 

12.5 

9.3 

7.2 

4.6 

3.1 

2.2 

1.7 

1.3 

24 

499 

181 

88.2 

50.5 

32 

21.8 

15.6 

11.6 

8.9 

5.7 

3.8 

2.8 

2.1 

1.6 

1 

26 

609 

221 

108 

61.7 

39.1 

26.6 

19 

14.2 

10.9 

7.1 

4.7 

3.4 

2.5 

1.9 

1.2 

28 

733 

266 

130 

74.2 

47 

32 

22.9 

17.1 

13.1 

8.3 

5.7 

4.1 

3 

2.3 

1.5 

30 

787 

316 

154 

88.2 

55.9 

38 

27.2 

20.3 

15.6 

9.9 

6.7 

4,8 

3.6 

2.8 

1.7 

36 

499 

243 

130 

88.2 

60 

43 

32 

24.6 

15.6 

10.6 

7.6 

5.7 

4.3 

2.8 

42 

733 

357 

205 

130 

88.2 

63.2 

47 

36.2 

19 

15.6 

11.2 

8.3 

6.4 

4.1 

48 

499 

286 

181 

123 

88.2 

62.7 

50.5 

32 

21.8 

15.6 

11.6 

8.9 

5.7 

54 

670 

383 

243 

165 

118 

88.2 

67.8 

43 

29.2 

20.9 

15.6 

12 

7.6 

60 

787 

499 

316 

215 

154 

115 

88.2 

55.9 

38 

27.2 

20.3 

15.6 

9.9 

PIPES,  FLUES,  AND  CHIMNEYS 


467 


HIGH-PRESSURE  GAS   DELIVERY— (F.  H.  OLIPHANT. 

\P~p 
Cubic  feet  per  hour  =  42a\/ — — . 

P  and  p  are  gauge  pressures  at  intake  and  discharge  ends  of  pipe  plus  15  Ibs.;    I  is  length  in 
yards;  a  for  different  sizes  of  pipe  is: 


Diameter 
Inside. 

Diameter 
Inside. 

a 

Diameter 
Inside. 

Diameter 
Outside. 

a 

0.25 

0.0317 

4 

34.1 

14.25 

15 

863 

0.50 

0.1810 

5 

60 

15.25 

16 

1025 

0.75 

0.5012 

6 

96 

17.25 

18 

1410 

1.0                   1.0000 

8 

198 

19.25 

20 

1860 

1.5 

2.9300 

10 

350 

Riveted 
20 

or  cast-iron 

pipes 
2055 

20 

5.9200 

12 

556 

24 

3285 

2.5 

10.3700 

16 

1160 

30 

5830 

3.0 

16.5 

18 

1570 

36 

9330 

TRANSMISSION    OF    GAS    OF   0.55    SPECIFIC    GRAVITY    THROUGH    A    PIPE   WITH    90° 

BENDS.     (NELSON  W.  PERRY) 


Inches,  Pressure. 

Cubic  Feet 
Delivered. 

Velocity  of  Flow 
in  Cubic  Feet  per 
Second. 

Increase  of 
Pressure  per  Bend, 
Inches. 

Total  Increased 
Pressure  per  25 
Bends,  Inches. 

Total  Initial 
Pressure,  Inches. 

1 

12,500 

40 

0.0016 

0.04 

1.04 

2 

18,000 

6.0 

0.0034 

0.085 

2.085 

3 

23,000 

8.0 

0.006 

0  .  1495 

3.15 

4 

25,500 

8.8 

0.0076 

0.189 

4.189 

5 

28,000 

9.6 

0.0086 

0.215 

5.215 

6 

32,000 

11.0 

0.0113 

0.28 

6.28 

7 

34,000 

12.0 

0  0135 

0.34 

7.34 

8 

36,000 

12.5 

0.0147 

0.39 

8.39 

9 

38,500 

13.0 

0.0158 

0.4 

9.4 

10 

40,000 

14.0 

0.0183 

0.46 

10.46 

Friction  Loss. — It  is  a  fact  not  generally  appreciated  that  gaseous  friction  in  pipes  de- 
pends, under  given  conditions,  upon  the  difference  of  the  squares  of  the  initial  and  terminal 
pressures.  Thus  the  drop  in  pressure  from  500  Ibs.  down  to  400  Ibs.  would  convey 
the  same  quantity  of  air  as  would  be  conveyed  by  the  drop  in  pressure  from  300  Ibs. 
down  to  atmospheric.  The  insignificant  increase  in  power  to  compress  to  500  Ibs. 
instead  of  300  Ibs.,  is  perfectly  well  known,  and  the  net  result  is  that  for  a  slightly 
greater  expenditure  for  pipe  line  and  for  energy  of  compression,  we  should  have  gas 
delivered  at  a  pressure  which  would  enable  it  to  be  used  directly  in  the  cylinder  of 
a  Diesel  engine  without  further  compression,  making  a  great  simplification  of  the 
engine  and  giving  an  enormous  capacity  of  transmission  to  a  pipe  line  of  very  mod- 
erate size. 


468 


GAS  PRODUCERS 


rt 


pq 


tf 


- 

g 

w 

02 

tf 

i 


g 

t» 
02 

w 


DIAMETER  OF  PIPE. 

10-inch. 

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4-inch. 

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PIPES,  FLUES,  AND  CHIMNEYS 


469 


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470 


GAS   PRODUCERS 


WEIGHT    OF    ROUND    GALVANIZED-IRON    PIPE    AND    ELBOWS    OF    THE    PROPER 

GAUGES   FOR  BLAST-PIPE   SYSTEMS 


Diameter  of 
Pipe, 
in  Inches. 

Gauge  of 
Iron. 

Weight  per 
Running  Foot 
in  Pounds. 

Actual 
Weight  of 
Full  Elbow. 

Diameter  of 
Pipe, 
in  Inches. 

Gauge  of 
Iron. 

Weight  per 
Running  Foot, 
in  Pounds. 

Actual 
Weight  of 
Full  Elbow. 

3 

25 

0.9 

0.6 

38 

18 

23.7 

179.8 

4 

25 

1.3 

1.1 

39 

18 

24.3 

189.4 

5 

25 

1.6 

1.6 

40 

18 

24.9 

199.2 

6 

25 

1.9 

2.3 

41 

16 

31.5 

258.4 

7 

25 

2.1 

3.0 

42 

16 

32.2 

270.7 

8 

25 

2.4 

3.9 

43 

16 

32.9 

283.3 

9 

25 

2.7 

4.9 

44 

16 

33.7 

296.2 

10 

25 

3.0 

6.0 

45 

16 

34.5 

310.3 

11 

24 

3.7 

8.2 

46 

16 

35.2 

323.8 

12 

24 

4.1 

9.8 

47 

16 

35.9 

337.6 

13 

24 

4.4 

11.4 

48 

16 

36.7 

352.6 

14 

24 

4.7 

13.2 

49 

16 

37.4 

367.0 

15 

24 

5.0 

15.1 

50 

16 

38.2 

381.6 

16 

24 

5.4 

17.1 

51 

16 

39.0 

397.6 

17 

22 

6.9 

23.5 

52 

16 

39.7 

412.8 

18 

22 

7.3 

26.3 

53 

16 

40.5 

430.5 

19 

22 

7.7 

29.3 

54 

16 

41.4 

447.5 

20 

22 

8.2 

32.8 

55 

16 

42.3 

464.8 

21 

22 

8.5 

35.9 

56 

16 

43.0 

481.3 

22 

22 

8.9 

39.3 

57 

16 

43.8 

499.2 

23 

20 

11.0 

50.7 

58 

16 

44.5 

516.2 

24 

20 

11.5 

55.1 

59 

16 

45.3 

533.6 

25 

20 

12.0 

59.9 

60 

16 

46.0 

552.5 

26 

20 

12.4 

64.3 

61 

14 

57.5 

701.5 

27 

20 

12.9 

69.9 

62 

14 

58.4 

724.2 

28 

20 

13.4 

75.2 

63 

14 

59.3 

747.2 

29 

20 

13.9 

80.6 

64 

14 

60.3 

771.8 

30 

20 

14.4 

86.3 

65 

14 

61.2 

795.6 

31 

20 

14.9 

92.4 

66 

14 

62.2 

821.4 

32 

18 

20.0 

127.4 

67 

14 

63.0 

844.2 

33 
34 

18 
18 

20.6 
21.2 

135.8 
144.2 

68 
69 

14 
14 

64.0 
65.0 

870.4 
897.0 

35 

18 

21.8 

152.7 

70 

14 

66.0 

924.0 

36 

18 

22.4 

161.5 

71 

14 

67.0 

951.4 

37 

18 

23.0 

170.5 

72 

14 

67.9 

977.5 

PIPES,  FLUES,  AND  CHIMNEYS 


471 


FACTOR  TABLE  FOR  REDUCING  THE  WEIGHT  OF  GALVANIZED-IRON  PIPE  OF  ONE 
GAUGE   TO   THAT   OF   ANOTHER   GAUGE 


03 

o 

GAUGE  AND  WEIGHT  IN  POUNDS  PER  SQUARE  FOOT. 

12 

13 

14 
3.28 

15 

16 

17 

18 

19 

20 

21 
1.53 

22 
1.41 

23 

24 

25 

26 

27 

28 

4.53 

3.91 

2.97 

2.66 

2.41 

2.16 

1.90 

1.66 

1.28 

1.16 

1.03 

0.91 

0.84 

0.78 

12 
13 
14 

15 
16 
17 

18 
19 
20 

21 
22 
23 

24 
25 
26 

27 
28 

1.00 
1.16 
1.38 

1.53 

1.70 

1.88 

0.86 
1.00 
1.19 

1.32 
1.47 
1.62 

0.72 
0.84 
1.00 

1.10 
1.23 
1.36 

0.66 
0.76 
0.91 

1.00 
1.11 
1.23 

0.59 
0.68 
0.81 

0.90 
1.00 
1.10 

0.53 
0.62 
0.74 

0.81 
0.91 
1.00 

0.48 
0.55 
0.66 

0.73 
0.81 
0.90 

0.42 
0.49 
0.58 

0.64 
0.71 
0.79 

0.37 
0.43 
0.52 

0.56 
0.62 
0.69 

0.34 
0.39 
0.47 

0.52 
0.58 
0.63 

0.31 
0.36 
0.43 

0.48 
0.53 
0.59 

0.28 
0.33 
0.39 

0.43 

0.48 
0.53 

0.26 
0.30 
0.35 

0.39 
0.44 

0.48 

0.23 
0.26 
0.32 

0.35 
0.39 
0.43 

0.20 
0.23 

0.28 

0.31 
0.34 
0.38 

0.19 
0.22 
0.26 

0.28 
0.32 
0.35 

0.17 
0.20 
0.24 

0.27 
0.29 
0.32 

2.10 
2.38 

2.72 

1.81 
2.06 
2.36 

1.52 
1.73 

1.98 

1.38 
1.56 
1.79 

1.23 

1.40 
1.60 

1.12 
1.27 
1.45 

1.00 
1.14 
1.30 

0.88 
1.00 
1.16 

0.77 
0.87 
1.00 

0.71 
0.81 
0.92 

0.65 
0.74 

0.85 

0.59 
0.67 
0.77 

0.54 
0.61 
0.70 

0.48 
0.54 
0.62 

0.42 

0.48 
0.55 

0.39 
0.44 
0.51 

0.36 
0.41 
0.47 

2.96 

2.56 

2.14 

1.94 

1.74 

1.57 

1.41 

1.24 

1.09 

1.00 

0.92 

0.84 

0.76 

0.67 

0.59 

0.55 

0.51 

3.21 

2.77 

2.32 

2.10 

1.89 

1.71 

1.53 

1.35 

1.18 

1.08 

1.00 

0.91 

0.82 

0.73 

0.65 

0.60 

0.55 

3.54 
3.90 

3.07 
3.37 

2.56 
2.82 

2.32 
2.56 

2.08 
2.29 

1.88 
2.08 

1.69 
1.86 

1.49 
1.61 

1.30 
1.43 

1.20 
1.32 

1.10 
1.22 

1.00 
1.10 

0.91 
1.00 

0.81 
0.89 

0.71 

0.78 

0.66 
0.72 

0.61 
0.67 

4.40 

3.79 

3.18 

2.88 

2.58 

2.34 

2.10 

1.86 

1.61 

1.49 

1.37 

1.24 

1.12 

1.00 

0.88 

0.82 

0.76 

4.98 

4.30 

3.60 

3.26 

2.92 

2.65 

2.37 

2.10 

1.82 

1.68 

1.55 

1.41 

1.27 

1.13 

1.00 

0.92 

0.86 

5.40 

4.66 

3.90 

3.54 

3.17 

2.87 

2.57 

2.28 

1.96 

1.82 

1.68 

1.52 

1.38 

1.23 

1.08 

1.00 

0.93 

5.81 

5.01 

4.20 

3.80 

3.41 

3.09 

2.77 

2.45 

2.13 

1.96 

1.81 

1.64 

1.49 

1.32 

1.17 

1.08 

1.00 

In  the  preceding  table  the  weights  as  given  include  the  weight  of  rivets  and 
solder,  and  due  allowance  has  been  made  for  laps  and  trimmings.  The  elbows  have 
the  internal  radius  equal  to  the  diameter  of  the  pipe.  Rectangular  pipes  are  usually 
made  of  the  same  gauge  as  round  pipes  of  equivalent  area. 

The  table  above  serves  for  the  estimation  of  weights  of  pipe  of  other  gauges  than 
those  given  in  the  preceding  table.  Thus,  suppose  it  is  desired  to  find  the  weight  of 
28-in.  pipe  made  of  No.  16  gauge.  From  the  preceding  table,  pipe  of  this  size  made 
of  No.  20  gauge  weighs  13.4  Ibs.  per  running  foot.  By  the  table  above,  the  figure 
found  at  the  junction  of  the  column  headed  16  and  the  line  designated  20  is  1.60; 
therefore,  the  weight  per  foot  of  No.  16  gauge  is  13.4  X  1.60  =  21.44  Ibs. 

Capacity  of  Flues. — It  is  necessary  to  provide  large  flue  capacity  and  to  carry 
the  full  area  right  up  to  the  furnace  ports,  which  latter  may  be  slightly  reduced  to 
give  the  gas  a  forward  impetus.  Generally  speaking,  the  net  area  of  a  flue  should  not 
be  less  than  one-sixteenth  of  the  area  of  the  gas-making  surface  in  the  producers 
supplying  it.  Or  it  may  be  stated  thus:  The  carrying  capacity  of  a  hot  gas  flue  is 
equivalent  to  200  Ibs.  of  coal  per  hour  per  square  foot  of  section.  Thus  a  brick-lined 
flue  4  ft.  diameter  inside  the  lining  will  carry  the  gas  made  from  2500  Ibs.  of  coal 
per  hour  (12^  sq.ft.  X  200),  and  wrill  serve  a  gas-making  area  of  200  sq.ft.  (12^X16), 
which  corresponds  to  four  8-ft.  producers. 


472  GAS   PRODUCERS 

In  addition  to  proper  size,  it  is  necessary  to  provide  proper  facilities  for  occa- 
sional cleaning  out.  The  accumulation  of  soot  is  not  very  rapid  unless  the  producers 
are  over-driven,  and  it  can  be  easily  burned  out  by  shutting  off  the  steam  from  the 
producers,  opening  a  few  cleaning  doors,  and  allowing  the  air  to  sweep  through  the 
hot  flue.  The  soot  takes  fire  and  burns  away.  If  time  is  short,  the  process  can  be 
hastened  by  using  a  by-pass  connection  to  the  stack,  so  as  to  get  its  draft  right  on 
the  flue  without  passing  through  the  furnace;  and  it  can  be  hastened,  if  necessary, 
by  hoeing  through  the  cleaning  doors  and  using  a  steam  jet  to  loosen  the  soot  from 
the  walls  of  the  flue. 

Natural  Gas  Measurement.— The  Chapin-Fulton  Manufacturing  Company  con- 
tributes the  following  information  on  the  measurement  of  the  volume  or  output  of 
natural  gas  wells  and  pipes : 

To  measure  the  volume  or  output  in  cubic  feet  per  hour  of  a  gas  well  or  of  any 
orifice  discharging  gas  into  the  atmosphere,  an  instrument  called  the  Pitot  Tube 
Gauge,  named  from  Pitot,  its  inventor,  is  used.  This  instrument  is  remarkable  for 
its  simplicity  and  accuracy  of  results,  and  its  principle  is  that  the  instrument  gives 
the  velocity  of  the  current  at  the  point  of  its  application,  which  velocity,  multiplied 
by  the  sectional  area  of  the  stream,  gives  the  volume  of  the  flow.  The  simplest  form 
of  the  instrument  is  a  small  tube  bent  at  right  angles,  the  open  end  of  which  is  inserted 
in  the  well  mouth  at  right  angles  to  the  flow,  and  to  the  opposite  end  of  which  is  attached 
a  pressure  gauge.  For  convenience  the  connection  may  be  made  with  a  piece  of 
flexible  hose.  For  wTells  of  light  volume,  a  U-water  or  mercury  gauge  is  used,  and 
if  the  wells  have  a  strong  flow  and  show  a  pressure  running  into  pounds,  an  accurate 
steam  gauge  must  be  used.  The  open  end  of  the  small  pipe  should  be  held  just  below 
the  top  of  the  pipe  or  flush  with  it,  and  at  one-fourth  of  the  diameter  from  the  outer 
edge. 

The  formula  from  which  the  following  tables  were  worked  out  was  first  applied 
to  flowing  gases  by  Prof.  S.  W.  Robinson,  of  the  Ohio  State  University,  in  which  the 
specific  gravity  of  the  gas  is  taken  at  0.6. 

The  number  of  cubic  feet  per  hour  that  will  pass  out  of  a  circular  opening  one 
inch  in  diameter  at  pressure  measured  by  a  column  of  water  or  mercury,  or  by  a 
spring  gauge,  is  given  in  the  following  tables.  The  third  table  contains  multipliers 
for  sizes  of  pipe  less  and  greater  than  one  inch. 

For  any  specific  gravity  other  than  0.6,  multiply  the  result  obtained  by 


0.6 


Specific  gravity  gas' 

For  temperature  of  flowing  gas  when  observed  above  60°  F.  deduct  1%  for  each  5°, 
and  add  a  like  amount  for  temperature  less  than  60°  F.  In  obtaining  the  approx- 
imate flow  of  a  gas  well,  these  corrections  are  usually  neglected. 

Example  1.  Suppose  it  is  required  to  find  the  cubic  feet  output  per  day  of  a 
gas  well  or  an  orifice  discharging  from  a  two-inch  opening,  the  gauge  in  the  Pitot 
tube  showing  a  water  pressure  of  5  inches.  In  Table  I,  opposite  this  figure  we  find 
3500  cubic  feet,  which  is  the  volume  discharged  by  a  one-inch  opening,  but  as  two- 


PIPFJS,  FLUES.  AND  CHLMXKVS 


473 


inch  pipe  was  the  size  on  which  the  test  was  made  this  amount  must  be  multiplied 
by  the  multiplier  in  the  third  table  for  two-inch  pipe,  which  is  4.  Then  we  have 
3500X4X24  hours -336,000  cu.ft.,  the  daily  flow. 

Example  2.  Suppose  it  is  required  to  find  the  output  per  day  of  a  gas  well  or 
orifice  discharging  from  a"  three-inch  opening,'  the  gauge  showing  a  pressure  of 
30  pounds.  Opposite  this  figure  in  Table  II  we  find  37,945.  Using  the  multiplier 
for  three-inch  pipe  in  Table  III,  which  is  9,  we  have  37,945X9X24  =  8,196,120  cu.ft. 
daily  output  of  well. 

TABLE  I— LOW-PRESSURE  DISCHARGE 

DISCHARGE     OF    GAS    OF    0.6     SPECIFIC     GRAVITY     FROM      1-INCH     OPENING,     CORRESPONDING     TO     WATER 

PRESSURE    IN    INCHES 


Pressure 
in  Inches. 

Cubic  Feet 
per  Hour. 

Pressure 
in  Inches. 

Cubic  Feet 
per  Hour. 

Pressure 
in  Inches. 

Cubic  Feet 
per  Hour. 

Pressure 
in  Inches. 

Cubic  Feet 
per  Hour. 

0.10 

495 

0.90 

1485 

3.50 

2928 

10.00 

4950 

0.20 

714 

1.00 

1555 

4.00 

3130 

11.00 

5215 

0.30 

857 

1.25 

1738 

4.50 

3321 

12.00 

5422 

0.40 

980 

1.50 

1915 

5.00 

3500 

13.85 

5800 

0.50 

1106 

1.75 

2070 

6.00 

3834 

20.77 

7110 

0.60 

1213 

2.00 

2214 

7.00 

4140 

27.70 

8200 

0.70 

1310 

2.50 

2475 

8.00 

4428 

• 

0.80 

1401 

3.00 

2712 

9.00 

4694 

TABLE  II— HIGH-PRESSURE  DISCHARGE 

DISCHARGE    OF   GAS     OF    0.6    SPECIFIC   GRAVITY    FROM    1-INCH    OPENING,    CORRESPONDING    TO   PRESSURE 
OF    MERCURY    COLUMN    AND     OF    GAUGE     PRESSURE 


Mercury 
Pressure 
in  Inches. 

Pounds 
Gauge 
Pressure 
per 
Square  Inch. 

Cubic  Feet 
per  Hour. 

Mercury 
Pressure 
in  Inches. 

Pounds 
Gauge 
Pressure 
per 
Square  Inch. 

Cubic  Feet 
per  Hour. 

Pounds 
Gauge 
Pressure 
per 
Square  Inch. 

Cubic  Feet 
per  Hour. 

0.10 

0.05 

1,835 

5.59 

2.75 

13,375 

14.00 

28,495 

0.20 

0.10 

2,590 

6.10 

3.00 

14,175 

15.00 

29,295 

0.30 

0.15 

3,170 

6.61 

3.25 

14,755 

16.00 

30,045 

0.40 

0.20 

3,655 

7.11 

3.50 

15,320 

17.00 

30,755 

0.50 

0.25 

4,095 

7.62 

3.75 

15,850 

18.00 

31,415 

0.60 

0.30 

4,490 

8.13 

4.00 

16,370 

20.00 

32,730 

0.70 

0.35 

4,850 

8.64 

4.25 

16,875 

22.00 

33,470 

0.80 

0.40 

5,180 

9.15 

4.50 

17,360 

25.00 

35,620 

0.90 

0.45 

5,495 

9.65 

4.75 

17,845 

30.00 

37,945 

1.02 

0.50 

5,790 

10.16 

5.00 

18,330 

35.00 

40,040 

1.52 

0.75 

7,095 

12.20 

6.00 

19,835 

40.00 

41,945 

2.03 

1.00 

8,195 

7.00 

21,555 

45.00 

43,605 

2.54 

1.25 

9,165 

8.00 

22,600 

50.00 

45,080 

3.05 

1.50 

10,030 

9.00 

23,735 

60.00 

47,380 

3.56 

1.75 

10,830 

10.00 

24,815 

75.00 

50,975 

4.07 

2.00 

11.550 

11.00 

25,915 

90.00 

54,350 

4  .57 

2.25 

12.27.') 

12.00 

26,775 

100.00 

55,705 

5.08 

2.50 

12,950 

13.00 

27,695 

110.00 

57,055 

474  GAS   PRODUCERS 

TABLE  III— MULTIPLIERS  FOR  PIPE  OF  OTHER  DIAMETERS  THAN  ONE  INCH 


Diameter 
in  Inches. 

Mulitplier. 

Diameter 
in  Inches. 

Multiplier. 

Diameter 
in  Inches. 

Multiplier. 

Diameter 
in  Inches. 

Multiplier. 

Diameter 
in  Inches. 

Multiplier^ 

A 

0.0038 

1 

1.00 

4 

16.00 

6 

36.00 

8 

64.00 

i 

0.0156 

H 

2.25 

4} 

18.00 

6i 

39.00 

8i 

68.00 

i 

0.0625 

2 

4.00 

5 

25.00 

6f 

43.90 

9 

81.00 

i 

0.2500 

2£ 

6.25 

ST^ 

26.90 

7 

49.00 

10 

100.00 

I 

0.5625 

3 

9.00 

6| 

31.60 

71 

52.50 

High  Pressures. — A  standard  cubic  foot  of  gas  is  a 
compression  equal  to  the  atmospheric  pressure,  which 
15  Ibs.     Now  suppose  gas  is  passing  through  a  meter  at 
then  each  cubic  foot  will  have  a  value  of  2.     The  gas 
of  two  atmospheres,  one  atmosphere  (15  Ibs.)  within  the 
external  pressure  of  the  atmosphere,  and  therefore  not 
one  atmosphere  (15  Ibs.)  indicated,  and  as  the  volume 
every  atmosphere,  we  have 


cubic  foot  measured  under  a. 
we  will  call  for  convenience 
a  gauge  pressure  of  15  Ibs., 
is  then  under  a  compression 
pipe,  counterbalanced  by  the 
indicated  on  the  gauge,  and 
of  gas  is  increased  once  for 


15+15 
15 


=  2. 


That  is,  a  cubic  foot  of  gas  measured  at  a  gauge  pressure  of  15  Ibs.  is  the  equivalent 
of  2  standard  feet.  It  must  be  remembered  that  gas  will  not  flow  from  a  pipe  until 
its  internal  pressure  is  equal  to  the  atmospheric  pressure.  If  it  were  less,  the  atmos- 
phere would  flow  into  the  pipe,  hence  we  must  always  assume  that  we  start  with  one 
atmosphere  (15  Ibs.)  before  the  gauge  begins  to  indicate.  Then  to  obtain  a  multi- 
plier for  gas  measured  at  any  number  of  Ibs.,  we  would  have  the  formula 


(i) 


in  which  p  is  the  gauge  pressure  in  Ibs. 

h  is  the  atmospheric  pressure  (assumed  15  Ibs). 
M  is  the  multiplier  required. 

But  the  atmospheric  pressure  is  a  little  less  than  15  Ibs,  and  for  the  elevations  gen- 
erally of  present  natural  gas  fields,  it  is  usually  taken  at  14.4  Ibs.,  and  substituting 
this  value  in  formula  (1),  we  have 


15  +  14.4 
14.4 


=  2.0416, 


which  is  the  multiplier  for  gas  measured  at  15  Ibs.  gauge  pressure,  and  sold  on  the 
atmospheric  basis. 

Again,  since  gas  is  usually  sold  at  standard  pressure  of  ounces  to  the  square  inch, 
we  must  add  this  pressure  to  the  divisor  in  formula  (1). 


PIPES,  FLUES,  AND  CHIMNEYS  475 

We  then  have  formula 


in  which  M  is  the  multiplier  required. 

p  is  the  guage  pressure  in  Ibs. 
h  is  the  atmospheric  pressure  of  14.4  Ibs. 
0.25  is  4-ounce  pressure  reduced  to  Ibs. 

For  Example. — Suppose  it  is  required  to  find  the  multiplier  for  gas  measured 
at  30  Ibs.  gauge  pressure,  and  sold  at  the  standard  pressure  of  4  ounces.  Then  sub- 
stituting the  known  quantities  in  formula  (2)  we  have 

30  +  14.4       44.4 
14.4 +  .25  "1^65" 

the  required  multiplier.  Hence,  if  the  meter  had  registered  1,000,000  cu.ft.  the 
correct  number  of  feet  at  4-ounce  pressure  would  be  1,000,000X3.0307  =  3,030,700 
cubic  feet. 

If  it  be  desired  to  sell  gas  on  any  other  basis  than  a  4-ounce  pressure,  then  we 
have  formula 

2^-M  (3} 

h  +  n~  .....     (3) 

in  which  p  is  the  gauge  pressure  in  Ibs. 

h  is  the  atmospheric  pressure  in  Ibs. 
n  is  the  agreed  pressure  or  basis  of  measurement  in  Ibs. 
M  is  the  multiplier  required. 

Example. — Suppose  it  is  required  to  sell  gas  at  one  Ib.  to  the  square  inch  as  the 
standard  of  measurement,  and  the  gauge  pressure  of  the  meter  is  25  Ibs.  Substituting 
known  values  in  formula  (3)  we  have 

25  +  14.4     39.4 


the  required  multiplier.     If  1,000,000  cu.ft.  has  been  registered  by  the  meter,  then 
1,000,000X2.5584  =  2,558,400,  the  correct  amount  at  a  standard  pressure  oM  Ib. 

In  like  manner  a  multiplier  may  be  obtained  for  any  standard,  delivered  at  any 
gauge  pressure. 

For  convenience  we  append  a  table  of  multipliers  to  be  used  for  guage  pressures 
greater  than  4  ounces  per  square  inch,  in  which  the  standard  is  4  ounces,  but  from  the 
foregoing  formula  multipliers  may  be  readily  figured  to  suit  any  conditions  of  mea- 
surement. 

In  this  table  decimals  are  carried  out  to  four  figures;  any  further  extensions  would 
not  change  the  result  more  than  100  cubic  feet  in  1,000,000. 


476 


GAS    PRODUCERS 


Gauge 
Pressure, 
Pounds 
per 
Sq.In. 

Multiplier 
or 
Density. 

Gauge 
Pressure, 
Pounds 
per 
Sq.In. 

Multiplier 
or 
Density. 

Gauge 
Pressure, 
Pounds 
per 
Sq.In. 

Multipliei 
or 
Density. 

Gauge 
Pressure, 
Pounds 
per 
Sq.In. 

Multiplier 
or 
Density. 

Gauge 
Pressure, 
Pounds 
per 
Sq.In. 

Multiplier 
or 
Density. 

0 

0.9829 

24* 

2.6553 

49* 

4.3617 

74* 

6.0682 

99* 

7.7747 

J 

1.0000 

25 

2.6894 

50 

4.3959 

75 

6  .  1023 

100 

7.8088 

4 

1.0170 

25* 

2.7235 

50* 

4.4300 

75* 

6.1365 

100* 

7.8430 

1 

1.0511 

26 

2.7577 

51 

4.4642 

76 

6  .  1706 

101 

7.8771 

1* 

1  .0853 

26* 

2.7918 

51* 

4.4983 

76* 

6.2047 

101* 

7.9112 

2 

1.1194 

27 

2.8259 

52 

4.5324 

77 

6.2389 

102 

7.9453 

21 

1  .  1535 

27* 

2.8600 

52* 

4.5665 

77* 

6.2730 

102* 

7.9795 

3 

1.1877 

28 

2.8942 

53 

4.6007 

78 

6.3071 

103 

8.0136 

Si 

1.2218 

28* 

2.9283 

53* 

4.6348 

78* 

6.3413 

103* 

8.0477 

4 

1.2559 

29 

2.9624 

54 

4.6689 

79 

6.3754 

104 

8.0819 

4* 

1.2901 

29* 

2.9966 

54* 

4.7031 

79* 

6.4095 

105 

8.1501 

5 

1.3242 

30 

3.0307 

55 

4.7372 

80 

6.4436 

106 

8.2184 

5* 

1.3583 

30* 

3.0648 

55* 

4.7713 

80* 

6.4778 

107 

8.2866 

6 

1.3924 

31 

3.0990 

56 

4.8055 

81 

6.5119 

108 

8.3549 

»4 

1.4266 

31* 

3.1331 

56* 

4.8396 

81* 

6.5460 

109 

8.4232 

7 

1.4607 

32 

3  .  1672 

57 

4.8737 

82 

6.5802 

110 

8.4914 

a 

1.4948 

321 

3.2013 

57* 

4.9079 

82* 

6.6143 

111 

8.5597 

8 

1.5290 

33 

3.2355 

58 

4.9420 

83 

6.6484 

112 

8.6279 

8J 

1.5631 

33* 

3.2696 

58* 

4.9761 

83* 

6.6825 

113 

8.6962 

9 

1.5972 

34 

3.3037 

59 

5.0102 

84 

6.7167 

114 

8.7645 

H 

1.6314 

34* 

3.3379 

59* 

5.0444 

84* 

6.7508 

115 

8.8327 

10 

1  .6655 

35 

3.3720 

60 

5.0785 

85 

6.7849 

116 

8.9010 

10* 

1.6996 

35* 

3.4061 

60* 

5.1126 

85* 

6.8191 

117 

8.9692 

11 

1.7338 

36 

3.4403 

61 

5  .  1468 

86 

6.8532 

118 

9.0375 

11* 

1.7679 

36* 

3.4744 

61* 

5.1809 

86* 

6.8873 

119 

9.1058 

12 

1.8020 

37 

3.5085 

62 

5.2150 

87 

6.9215 

120 

9  .  1740 

124 

1  .8361 

37* 

3.5426 

62* 

5.2491 

87* 

6.9556 

121 

9.2423 

13 

1.8703 

38 

3.5768 

63 

5.2833 

88 

6.9897 

122 

9.3105 

13* 

1.9044 

38* 

3.6109 

63* 

5.3174 

88* 

7.0238 

123 

9.3788 

14 

1.9385 

39 

3.6450 

64 

5.3515 

89 

7.0580 

124 

9.4471 

14* 

1.9727 

39* 

3.6792 

64* 

5.3856 

89* 

7.0921 

125 

9.5153 

15 

2.0068 

40 

3.7133 

65 

5.4198 

90 

7  .  1262 

126 

9.5836 

15* 

2.0409 

40* 

3.7474 

65* 

5.4539 

90* 

7  .  1604 

127 

9.6518 

16 

2.0751 

41 

3.7816 

66 

5.4880 

91 

7  .  1945 

128 

9.7201 

16* 

2  .  1092 

41* 

3.8157 

66* 

5.5221 

91* 

7.2286 

129 

9.7884 

17 

2  .  1433 

42 

3.8498 

67 

5.5563 

92 

7.2628 

130 

9.8566 

17* 

2.1774 

42* 

3.8839 

67* 

5.5904 

92* 

7.2969 

131 

9.9249 

18 

2.2116 

43 

3.9181 

68 

5.6245 

93 

7.3310 

132 

9.9931 

184 

2.2457 

43* 

3.9522 

68* 

5.6587 

93* 

7.3651 

133 

10.0614 

19 

2.2798 

44 

3.9863 

69 

5.6928 

94 

7.3993 

134 

10  .  1296 

19* 

2.3140 

44* 

4.0205 

69* 

5.7269 

94* 

7.4334 

135 

10  .  1979 

20 

2.3481 

45 

4.0546 

70 

5.7610 

95 

7.4675 

136 

10.2662 

20* 

2.3822 

45* 

4.0887 

70* 

5.7952 

95* 

7.5017 

137 

10.3344 

21 

2.4164 

46 

4.1228 

71 

5.8293 

96 

7.5358 

138 

10.4027 

21* 

2.4505 

46* 

4  .  1570 

71* 

5.8634 

96* 

7.5699 

139 

10.4709 

22 

2.4846 

47 

4.1911 

72 

5.8976 

97 

7.6041 

140 

10.5392 

22* 

2.5187 

47* 

4.2252 

72* 

5.9317 

97* 

7.6382 

141 

10.6075 

23 

2.5529 

48 

4.2592 

73 

5.9658 

98 

7.6723 

142 

10.6757 

23* 

2.5870 

48* 

4.2935 

73* 

6.0000 

98* 

7.7064 

24 

2.6212 

49 

4.3276 

74 

6.0341 

99 

7.7406 

PIPES,  FLUES,  AND  CHIMNEYS  477 


CHIMNEYS 


The  chimneys  of  furnaces  should  be  so  designed  as  to  relieve  the  furnace 
of  the  products  of  combustion  as  rapidly  as  formed  and  maintain  thereby  an 
equilibration  of  pressure  therein.  This  service  must  lie  between  two  extremes, 
both  of  which  tend  to  evil  results,  and  may  be  termed  insufficient  and  over- 
ventilation. 

From  the  first,  the  accumulation  of  inert  gases  in  the  furnace  form  a  back  pres- 
sure or  damper  upon  combustion,  and  retard  the  reliability  of  combustion  and  the 
efficiency  of  the  furnace. 

Upon  the  second,  or  over-ventilation,  the  tendency  is  either  to  draw  in  an  excess 
of  air  through  any  apertures,  fissures,  or  cracks  which  may  exist,  and  thereby  reduce 
the  temperature  of  the  furnace,  or  it  may  carry  the  products  of  combustion  away 
from  the  flame  with  such  rapidity  that  there  is  not  sufficient  time  contact  between 
these  products  and  the  contents  of  the  furnace,  the  mufflers,  or  reverberators,  with 
the  result  that  their  sensible  heat  is  not  absorbed  and  escapes  unused  into  the  atmos- 
phere. 

The  net  loss  of  this  latter  is  of  course  less  in  the  case  of  recuperators  or  regenerators 
where  it  is  possible  to  recover  a  portion  of  this  heat,  but  naturally  the  efficiency  of  such 
apparatus  in  the  cycle  is  lower  than  the  direct  contact  of  the  hot  gases  to  the  object 
to  be  heated. 

The  rate  of  flow  of  the  products  of  combustion  varies  and  it  is  usually  a  func- 
tion of  temperature  where  natural  gas  is  used.  In  small  house  chimneys  it  is  frequently 
as  low  as  3  to  4  ft.  per  second.  In  that  of  boiler  chimneys  from  6  to  15  ft.  per  second, 
while  in  furnace  chimneys  as  high  as  from  10  to  20  ft.  per  second.  The  temperature 
of  the  first  will  probably  lie  between  100  to  200°  C.  (200°  to  350°  F.),  the  second- 
class  between  100  to  300°  C.  (200  to  550°  F.),  and  in  the  last  between  300  to  1000°  C. 
(550  to  1800°  F.). 

There  are  many  more  or  less  intricate  formula  for  calculating  the  size  and  height 
of  chimneys,  but  as  a  practical  consideration  it  must  be  borne  in  mind  that  the  pull 
or  suction  of  a  chimney  is  purely  a  matter  of  equilibrium  between  the  weight  of  a 
column  of  hot  gases  and  the  weight  of  an  equal  column  of  air  at  atmospheric  tem- 
perature. If  the  volume  of  the  one,  multiplied  by  its  specific  gravity  at  its  average 
temperature,  giving  its  weight,  be  subtracted  from  that  of  the  other  at  atmospheric 
temperature,  the  difference  will  represent  the  amount  of  pressure  or  pull  exerted 
over  the  area  or  cross-section  of  the  chimney.  This  will  represent  the  total  head 
from  which,  for  practical  purposes,  must  be  subtracted  the  velocity  head  and  the 
friction  head,  the  remainder  equaling  the  net  or  available  head. 

The  formula  given  by  Richards  in  his  metallurgical  calculations  for  the  head  of 
gases  in  the  chimney  due  to  their  heated  condition  in  terms  of  external  air,  is  in 
English  units. 


478  GAS   PRODUCERS 


1  -D+^QiW  -32)  -D(t'  -32)] 


ho  =  total  head  of  air  in  ft.,  at  32°  F. 
H  =  height  of  chimney  in  ft. 

t  =  temperature  in  chimney. 

t'  =  temperature  of  air  outside. 
D  =  specific  gravity  of  chimney  gas,  air  =  l. 

Friction  head  may  be  said  to  be  a  function  of  the  roughness  of  the  walls  and  has 
been  empirically  determined  to  be  about  -faH.     It  can  be  expressed  in  the  formula 


h  (friction)-  1.91 

where  K  is  0.05  for  a  smooth  interior,  to  0.12  for  a  rough  one,  the  average  being 
0.08,  and  d  the  diameter  or  side  of  square  section. 

The  above  equations  are  given  merely  to  show  the  basis  for  calculation  in  ascer- 
taining ventilation.  For  all  practical  purposes,  tables  are  sufficiently  accurate  for 
purposes  of  practice,  and  they  may  be  checked  by  calculating  along  the  lines  above 
indicated. 

About  150  ft.  represents  the  practical  maximum  height  of  chimneys;  for  greater 
capacity,  chimneys  in  multiple  should  be  used. 

Chimney  Draft.  —  The  influence  of  temperature  upon  chimney  draft  is  given  by 
Sturtevant,  who  says  that  the  changes  in  the  temperature,  either  of  the  external 
atmosphere  or  the  gases  within  the  chimney,  have  a  most  marked  influence  upon 
the  draft,  is  very  clearly  shown  in  the  table  below,  in  which  the  draft,  as  indicated  in 
inches  of  water,  is  given  for  a  chimney  100  feet  high,  with  various  internal  and  ex- 
ternal temperatures.  For  any  other  height  of  chimney  than  100  feet,  the  height  of 
the  water  column  is  directly  proportional  to  that  of  the  chimney.  Hence  doubling 
the  height  doubles  the  draft.  This  is  not  to  be  confused  with  the  fact  that  the  velocity 
which  the  draft  has  power  to  create  and  the  corresponding  volume  of  air  moved 
vary  as  the  square  root  of  the  height.  This  table  clearly  indicates  the  necessity  of 
high  chimney  temperatures  for  ample  draft,  and  readily  accounts  for  the  stronger 
draft  which  exists  in  cold  weather  because  of  the  greater  temperature  difference. 

The  ordinary  form  of  draught-gauge,  consisting  of  a  U-tube  containing  water, 
lacks  sensitiveness  when  used  for  measuring  small  quantities  of  draught.  The  Barrus 
draft-gauge  multiplies  the  indication  of  the  ordinary  U  tube  as  many  times  as  may 
be  desired.  This  instrument  consists  of  a  tube,  usually  made  of  half-inch  glass,  which 
is  surmounted  by  two  glass  chambers  having  a  diameter  of  about  2J  ins.,  being 
arranged  in  the  manner  shown  in  Fig.  62.  It  is  placed  in  a  wooden  case  provided 
with  a  cover,  the  outside  dimensions  being  6^X20  in.;  this  is  screwed  to  the  wall  in 


PIPES,  FLUES,  AND  CHIMNEYS 


479 


HEIGHT     OF    WATER    COLUMN    DUE    TO    UNBALANCED    PRESSURES    IN    CHIMNEY 

100  FEET   HIGH 


Tempera- 
ture in 
Chimney. 

TEMPERATURE  OF  EXTERNAL  AIR. 

0° 

10° 

20° 

30° 

40° 

50° 

60° 

70° 

80° 

90° 

100° 

200° 

0.453 

0.419 

0.384 

0.353 

0.321 

0.292 

0.263 

0.234 

0.209 

0.182 

0.157 

220 

0.488 

0.453 

0.419 

0.388 

0.355 

0.326 

0.298 

0.269 

0.244 

0.217 

0.192 

240 

0.520 

0.488 

0.451 

0.421 

0.388 

0.359 

0.330 

0.301 

0.276 

0.250 

0.225 

260 

0  .555 

0.528 

0.484 

0.453 

0.420 

0.392 

0.363 

0.334 

0.309 

0.282 

0.257 

280 

0.584 

0.549 

0.515 

0.482 

0.451 

0.422 

0.394 

0.365 

0.340 

0.313 

0.288 

300 

0.611 

0.576 

0.541 

0.511 

0.478 

0.449 

0.420 

0.392 

0.367 

0.340 

0.315 

320 

0.6?  7 

0.603 

0.568 

0.538 

0.505 

0.476 

0.447 

0.419 

0.394 

0.367 

0.342 

340 

0.662 

0.638 

0.593 

0.563 

0.530 

0.501 

0.472 

0.443 

0.419 

0.392 

0.367 

360 

0.687 

0.653 

0.618 

0.588 

0.555 

0.526 

0.497 

0.468 

0.444 

0.417 

0.392 

380 

0.710 

0.676 

0.641 

0.611 

0.578 

0.549 

0.520 

0.492 

0.467 

0.440 

0.415 

400 

0.732 

0.697 

0.662 

0.632 

0.598 

0.570 

0.541 

0.513 

0.488 

0.461 

0.436 

420 

0.753 

0.718 

0.684 

0.653 

0.620 

0.591 

0.563 

0.534 

0.509 

0.482 

0.457 

440 

0.774 

0.739 

0.705 

0.674 

0.641 

0.612 

0.584 

0.555 

0.530 

0.503 

0.478.. 

460 

0.793 

0.758 

0.724 

0.694 

0.660 

0.632 

0.603 

0.574 

0.549 

0.522 

0.497' 

480 

0.810 

0.776 

0.741 

0.710 

0.678 

0.649 

0.620 

0.591 

0.566 

0.540 

0.515 

500 

0.829 

0.791 

0.760 

0.730 

0.697 

0.669 

0.639 

0.610 

0.586 

0.559 

0.534 

an  upright  position.  Two  different  liquids,  which  will  not  mix  and  which  are  of 
different  color,  are  used  for  filling  the  instrument,  one  occupying  the  portion  A,  B, 
and  the  other,  which  is  the  heavier  of  the  two,  the  portion  B,  C,  D. 
When  the  right-hand  tube  is  connected  to  the  flue,  the  suction  pro- 
duced by  the  draught  draws  the  line  of  demarcation  B  downward, 
and  the  amount  of  motion  is  proportional  to  the  difference  in  the 
areas  of  the  two  chambers  and  of  the  U-tube,  modified  somewhat 
by  the  difference  in  the  specific  gravity  of  the  liquids.  By  referring 
to  the  scale  on  the  side  the  amount  of  motion  is  measured.  This 
scale  is  movable,  and  can  be  adjusted  to  the  zero-point  by  loosen- 
ing the  thumb-screws.  The  liquids  generally  employed  are  alcohol 
colored  red  and  a  certain  grade  of  petroleum  oil.  A  multiplication 
varying  from  8  to  10  times  is  obtained  in  the  instrument  shown;  in 
other  words,  with  one-quarter  inch  draft,  the  movement  of  the  line 
of  demarcation  is  from  2  in.  to  2^  in.,  the  exact  amount  of  multiplica- 
tion being  determined  by  calibration  referred  to  a  standard  instrument. 

Weight  of  Chimney  Gas. — Prof.  Junkers  in  an  article  upon  the  ''Removal  of  Flue 
Gases  from  Gas  Fires,"  in  the  Journal  of  Gas  Lighting  (Apr.  14th,  1908),  discusses 
chimneys  at  length,  an  excerpt  of  his  remarks  being  herewith  given: 

"  In  order  that  the  combustion  products  may  be  carried  away  at  the  proper 
speed,  a  certain  amount  of  energy  derived  from  the  ascensional  force  of  the  gases  is 
required  to  overcome  the  resistance  in  the  flue.  This  force  depends  upon  the  height 
of  the  flue  and  the  specific  gravity  of  the  products.  It  is  shown  that,  at  any  given 


FIG.  240. — Barrus 
Draft  Gage. 


480  GAS   PRODUCERS 

temperature,  the  removal  of  the  water  vapor  increased  the  specific  gravity  of  the 
gases  and  diminishes  their  ascensional  force,  and  that  an  excess  of  air  prevents  con- 
densation, and  is,  accordingly,  advantageous  both  in  maintaining  the  ascensional 
force  and  in  preserving  the  inner  surface  of  chimneys  from  injury  by  condensation." 

The  gravity  of  the  waste  products  depends  also  upon  their  temperature.  It 
must  be  understood,  however,  that  this  is  the  mean  temperature,  since  a  reduction  in 
the  temperature  of  the  gases  at  the  inlet  of  a  flue,  brought  about  by  the  introduction 
of  some  air  there,  does  not  necessarily  involve  a  reduction  of  the  mean  temperature 
of  the  gases  within  the  flue. 

From  a  properly  designed  flue  the  gases  escape  at  a  temperature  still  exceeding 
that  of  the  surrounding  atmosphere.  If  the  chimney,  however,  removes  so  much  heat 
from  the  eases  that  they  fall  almost  to  the  temperature  of  the  air  before  leaving  the 
top,  water  may  be  condensed  so  that  the  residual  gas  becomes  heavier  than  air,  and 
the  draft  of  the  flue  is  damped.  It  may  happen  during  a  very  hot  day  after  cold 
weather  that  the  walls  of  the  flue  are  cooler  than  the  air,  when  a  definite  down-draft 
may  be  established. 

If  a  domestic  heating  apparatus,  consisting  of  stove  and  chimney,  is  so  erected  that 
both  the  top  and  bottom  of  the  chimney  are  equally  exposed  to  the  wind,  no  practical 
interference  with  the  chimney  is  likely  to  result;  but  if  one  end  of  the  flue  is  more 
exposed  than  the  other,  as  usually  obtains  in  houses,  the  effect  may  be  either  an  increase 
or  decrease  in  the  draft,  according  to  the  suction  or  pressure  exerted  by  the  wind 
at  the  outlet  of  the  chimney  and  in  the  apartment.  The  conditions  are  always 
alterable  by  opening  or  closing  windows  in  the  room,  according  to  the  direction  of  the 
wind. 

Smoke. — Smoke,  whether  produced  from  gaseous  or  direct  firing,  is  usually  the 
product  of  (a)  relative  low  temperature  of  fuel  bed,  or  (6)  excess  depth  of  fuel  bed.  As 
a  matter  of  fact  visible  smoke  is  usually  tarry  vapor  or  hydrocarbons  from  the  distilla- 
tion zone  which  have  been  distilled  at  a  temperature  lower  than  their  point  of  ignition. 
These  vapors  of  course  entrain  lamp  black  and  dust  which  are  carried  upward  with 
them  by  the  gases  of  combustion.  The  smoke  derived  from  combustion  of  producer 
gas  is  rarely  of  an  objectionable  nature,  but  is  occasionally  apparent  for  the  reasons 
aforementioned. 

In  discussing  the  subject  of  smoke  in  his  work  on  "  Liquid  and  Gaseous  Fuels  " 
(p.  17),  Professor  Lewes  says  as  follows: 

'  "  Of  the  three  gaseous  products  of  combustion  steam  alone  plays  an  important 
part  in  the  formation  of  smoke,  whilst  the  other  important  constituents  are  tar  vapor, 
minute  particles  of  unburned  carbon,  and  ash,  drawn  upwards  by  the  draft  created 
by  the-  fire. 

"  The  popular  idea  held  by  many  is  that  smoke  consists  mainly,  if  not  entirely,  of 
particles  of  carbon  rendered  slightly  adhesive  by  tarry  matters,  and  that  it  is  in  fact 
like  the  soot  found  deposited  in  the  chimney.  But  a  microscopic  examination  of  smoke 
reveals  a  far  more  interesting  condition  of  things.  A  very  beautiful  experiment, 
first  made  by  Mr.  Frederick  Hovenden,  is  to  show  that  if  one  takes  the  smoke  from  a 
cigar  or  cigarette,  and  blows  it  into  a  little  glass  chamber  highly  illuminated  from  below 
by  focusing  upon  it  the  beam  from  an  electric  lantern  or  limelight,  and  examines  it 
under  a  microscope,  it  presents  a  most  remarkable  and  wonderful  appearance.  Such 


PIPES,  FLUES,  AND  CHIMNEYS  481 

smoke  contains  no  particle  of  free  carbon,  but  appears  to  consist  of  an  immense  number 
of  little  round  particles  in  the  wildest  condition  of  commotion  and  movement,  each 
particle  rushing  about  and  never  coming  in  contact  with  its  neighbor.  Indeed,  it 
presents  as  beautiful  a  picture  as  one  could  imagine  of  the  molecular  movement  with 
which  theorists  have  endowed  matter.  On  still  further  examination  these  little 
particles  prove  to  be  tiny  vesicles,  the  skins  of  which  are  formed  of  condensed  vapor 
and  liquids  from  the  burning  substances  which  give  rise  to  them.  These  vesicles,  being 
filled  with  gases,  are  excessively  light,  and  float  in  the  atmosphere  until  brought  forcibly 
in  contact  with  some  surface,  which  causes  them  to  burst  and  deposit  the  liquid  film, 
so  setting  the  contents  free. 

"  Whether  this  cloud  of  floating  vesicles  be  derived  from  a  cigarette,  a  coal  fire,  or 
other  source,  if  they  are  collected  in  such  a  way  as  by  friction  to  cause  the  tiny  vessels 
to  burst,  one  obtains  a  liquid  which  comes  under  the  generic  heading  of  "  tar,"  this 
tar  being  a  highly  complex  mixture  of  many  different  organic  liquids  formed  by  the 
action  of  heat  on  the  constituents  of  the  burning  matter,  whilst  the  gases  which  escape 
from  the  interior  of  the  vesicles  on  the  rupture  of  the  skin  consist  of  nitrogen,  carbon 
dioxide,  carbon  monoxide,  hydrogen,  trace  of  oxygen,  and  such  hydrocarbons  as  methane. 

"The  smoke,  however,  from  the  combustion  of  oil  or  coal,  when  burned  with  an  in- 
sufficient air  supply,  forms  a  heavy  black  cloud,  the  deepening  of  density  and  color 
being  due  to  the  presence  in  it  of  minute  particles  of  unconsumed  carbon,  which  have 
been  deposited  by  premature  cooling  or  during  secondary  chemical  actions  taking 
place  in  the  flame  of  the  burning  material. 

"The  domestic  grate  using  bituminous  coal  is  the  chief  cause  of  the  smoke  curse, 
which  pollutes  our  town  atmospheres. 

"  The  idea  that  smoke  means  a  large  waste  of  fuel  is  erroneous,  and,  in  point  of  fact, 
the  carbon  wasted  as  soot  is  extremely  small,  and  varies  in  smoke  with  the  state  of  the 
fuel  which  is  fed  on  to  the  fire.  Under  the  ordinary  conditions,  experienced  in  any 
ordinary  fire  grate,  in  which  the  fire  has  just  been  made  up  with  bituminous  coal,  the 
heavy  smoke  escaping  will  contain  on  an  average  1£%  of  the  total  weight  of  fuel  con- 
sumed, and  as  the  temperature  of  the  mass  gradually  increase,  this  falls  to  less  than 
$%,  whilst  when  the  fire  is  burning  clear,  no  smoke  at  all  is  given  off.  In  the  same 
way  that  we  have  a  rapid  fall  in  the  carbons  given  off  as  soot,  so  we  also  find  a  fall  in 
the  hydrocarbons  liberated  as  tar  vapor,  whilst  the  gases  evolved  as  products  of  com- 
bustion vary  in  the  same  way  with  the  condition  of  the  fire.  When  the  coal  is  first  put 
on  the  fire  imperfect  combustion  in  its  mass  takes  place,  and  the  gases  passing  up  the 
flue  under  these  conditions  will  closely  approximate  to  the  following  analysis: 

Carbon  dioxide 0 . 70 

Methane 0 . 36 

Hydrogen 0 . 29 

Carbon  monoxide 0.01 

Oxygen 19 . 85 

Nitrogen 79 . 79 

showing  that  the  combustion,  owing  to  the  cooled  surface  at  the  top  of  the  fire  and 
excessive  dilution  with  inert  nitrogen,  is  very  incomplete.  Gradually,  however,  as  the 


482  GAS   PRODUCERS 

temperature  rises,  less  and  less  combustible  matter  escapes,  whilst  as  soon  as  the  fire 
begins  to  burn  clear,  the  products  of  combustion  are  practically  simply  carbon  dioxide 
and  water  vapor." 

Dr.  Lewes  also  gives  his  analysis  of  the  smoky  elements  of  the  atmosphere  which 
have  been  precipitated  on  the  roofs  of  some  orchid  houses  at  Chelsea  by  rain  or  snow, 
which  is  as  follows: 

Carbon 39.00% 

Hydrocarbons 12.30% 

Organic  bases 1  •  20% 

Sulphuric  acid 4 . 33% 

Ammonia 1  •  37% 

Metallic  iron  and  magnetic  oxide 2 . 63% 

Other  mineral  matter,  chiefly  silica  and  ferric  oxide 31 .24% 

Water  not  determined. 


CHAPTER  XXI 
MATERIALS:    FIRE  CLAY,   MASONRY,  WEIGHTS,  AND  ROPE 

FIRE  CLAYS 

E.  P.  PAGE  and  W.  J.  REES,  make  the  following  comments  in  an  article  upon  the 
valuation  of  "Fire  Clays  "  in  the  Gas  World,  Feb.  22d,  1908,  a  digest  of  which  is  as 
follows : 

A  clay  cannot  be  considered  refractory  which  is  not  eqifcl  in  fire-resisting  pro- 
perties to  Cone  26,  in  the  Seger  series  (about  1650°  C.).  The  rule  adopted  by  the 
German  Association  of  Fire-brick  Manufacturers,  is:  "The  limits  of  refractoriness 
is  to  be  considered  as  exceeded  when  the  material,  or  one  of  its  constituents,  uniformly 
distributed  in  fragments,  begins  to  melt  or  separate  by  liquidation;  not  only  the  sur- 
face of  the  piece  tested,  but  also  the  face  of  the  fracture  must  be  taken  into  considera- 
tion when  judging." 

Chemical  analysis  is  of  value  as  indicating  the  presence  or  absence  of  deleterious 
substances.  A  large  portion  of  fluxing  impurities,  such  as  iron  oxides,  lime,  titanium, 
alkalies,  etc.,  will  naturally  seriously  affect  the  value  of  a  clay.  The  usual  method 
of  using  the  ultimate  analysis  is  to  consider  only  the  ratio  of  total  fluxes  to  silica; 
out  Richter,  Bischof,  and  Seger  showed,  years  ago,  that  this  was  unsatisfactory,  as  it 
left  the  alumina  contents  of  the  clay  entirely  out  of  consideration.  The  primary 
ratio  to  be  taken  into  consideration  is  that  of  silica  to  alumina,  and  it  is  the  ratio  of 
total  fluxes  to  this  ratio  which  is  important.  The  exact  state  of  the  presence  of  the 
silica  in  the  clay  is  also  very  important.  If  this  is  in  a  fine  amorphous  state  it  may 
be  lead  to  fluxing,  while,  if  in  comparatively  coarse  particles,  it  renders  the  clay  more 
refractory. 

A  mineralogical  analysis  by  treatment  with  sulphuric  acid  and  caustic  soda  to 
remove  the  clay,  and  treating  the  residue  for  the  determination  of  alumina,  iron,  and 
alkalies,  is  useful,  and  gives  good  practical  information,  indicating,  to  some  extent, 
the  probable  behavior  of  clays  at  high  temperatures  as  to  fusibility. 

In  a  mechanical  analysis,  the  clay  is  first  broken  down  by  boiling,  and  a  micro- 
scopical examination  of  the  coarser  particles  is  made.  To  obtain  definite  informa- 
tion and  measurement  of  the  grains  recourse  must  be  had  to  elutriation. 

The  specific  gravity  and  porosity  are  useful  in  determining  the  structure  of  the 
manufactured  article,  the  porosity  test  being  generally  considered  the  most  useful. 
At  the  present  time  the  porosity  is  expressed  either  as  the  percentage  of  water  absorbed 
by  a  given  weight  of  dry  brick,  or  else — and  more  rationally — as  the  volume  of  pore 

483 


484  GAS    PRODUCERS 

space  to  that  of  the  brick.  The  term  "  specific  gravity  "  is  also  used  ambiguously  as 
being  either  the  gravity  of  the  clay  or  as  that  of  the  whole  piece. 

The  old  method  of  testing  refractoriness  by  mixing  pure  quartz  sand  with  clay 
to  be  tested  and  determining  the  proportion  of  sand  necessary  to  cause  the  test 
piece  to  run  to  a  liquid  at  same  temperature  as  a  standard  clay,  was  not  satisfactory. 
Bischof  used  standard  clays  as  a  means  of  comparison,  and  Seger  adopted  mixtures 
of  silica,  alumina,  etc.,  forming  the  mixtures  into  "  cones."  The  most  modern,  and, 
it  is  claimed,  the  most  accurate,  method,  is  to  expose  the  clay  to  the  high  temperatures 
of  the  electric  furnace.  Inasmuch,  however,  as  furnace  gases,  dust,  and  time  factor 
enter  into  the  question,  a  comparison  with  standard  mixtures  of  comparative  purity 
for  the  same  length  of  time  and  at  the  same  furnace  temperature  is  of  greater  value 
than  the  limit  of  refractoriness  in  so  many  degrees. 

Fire-Brick  Testing. — The  temperature  of  resistance  of  fire  bricks  in  producers  is 
not  high,  rarely  exceeding  2000°  or  a  maximum  of  2500.  This  does  not  require  a 
highly  recalcitrant  brick  and  the  ordinary  No.  3  grade  is  what  is  usually  used. 

Brick  should  be  well  shaped,  clean  cut,  in  order  to  make  tight  joints,  which  is 
the  principal  requisite,  and  should  be  sufficiently  hard  to  resist  erosion  by  clinkering. 

The  tests  to  apply  to  fire-brick  to  determine  its  quality,  according  to  the  trustees 
of  the  gas  educational  class,  are  as  follows: 

The  qualities  desired  in  fire-brick  are:  infusibility,  strength,  regularity  of  shape, 
uniformity  of  composition,  and  facility  of  cutting;  and  the  tests  to  be  applied  to  a 
fire-brick  should  be  such  as  to  determine  to  what  extent  it  possesses  these  qualities. 

The  degree  of  infusibility  can  be  determined,  to  a  certain  extent,  by  an  analysis 
of  the  material  of  which  the  brick  is  composed.  If  this  analysis  shows  the  presence 
of  about  60%  of  silica,  less  than  6%  of  sesqui-oxide  of  iron  and  not  more  than  2  to 
3%  as  a  total  of  lime,  magnesia,  and  the  hydrates  of  potassium  and  sodium,  the  brick 
probably  posseses  a  high  degree  of  infusibility.  If  the  analysis  shows  more  than  6% 
of  sesqui-oxide  of  iron  or  2  to  3%  of  the  lime,  magnesia,  etc.,  the  brick  should  be  re- 
jected. But  exposure  of  the  brick  to  the  action  of  heat  under  the  conditions  to  which 
it  will  be  subjected  when  used  furnishes  the  best  test  for  infusibility.  In  coal  gas 
works  the  test  can  be  made  by  placing  the  brick  in  the  combustion  chamber  of  a 
regenerative  bench.  If,  when  the  brick  is  removed  after  being  exposed  for  a  week 
or  ten  days  to  the  heat  of  the  combustion  chamber,  the  edges  and  corners  are  found 
to  be  sharp,  and  the  surfaces  show  no  signs  of  incipient  fusion,  the  brick  may  be  passed 
as  a  first-class  quality,  as  far  as  infusibility  is  concerned.  In  water-gas  plants  the 
space  at  the  bottom  of  the  super-heater,  in  which  the  secondary  combustion  occurs, 
furnishes  a  good  place  for  the  test. 

If  the  material  of  which  the  brick  is  made  is  well  compressed  during  manu- 
facture, and  the  brick  is  hard  burned  there  is  no  question  as  to  its  strength  when 
cold.  The  degree  to  which  compression  has  been  carried  is  indicated  by  the  weight 
of  the  brick,  and  a  fire-brick  of  the  regulation  size,  9  in.  X4£  in.  X2^  in.,  should  weigh 
from  1\  to  7^  Ibs.  A  well  burnt  brick  usually  shows  a  reddish  tinge.  A  well 
compressed  and  well  burnt  brick  will  give  a  ringing  sound  when  struck  with  a  ham- 
mer. It  is  especially  important  that  the  bricks  that  are  to  be  used  for  lining  the 
furnaces  of  retort  benches,  or  for  lining  water  gas  generators,  should  be  hard,  since 
they  are  subjected  to  a  great  deal  of  abrasion  from  the  fuel  and  the  clinkering  bars, 


MATERIALS:    FIRE  CLAY,  MASONRY,  WEIGHTS,  AND  ROPE         485 

so  that  for  this  work  hardness  and  strength  are  of  more  importance  than  infusibility. 
In  the  combustion  chamber,  on  the  contrary,  infusibility  is  the  most  important  quality, 
since  the  material  used  there  is  not  exposed  to  any  wear  and  tear  except  that  aris- 
ing from  the  effect  of  the  heat.  It  may  thus  frequently  happen  that  the  same  brick 
is  not  suitable  for  use  both  in  the  furnace  and  the  combustion  chamber.  An  ex- 
amination of  the  exterior  of  the  brick  is  all  that  is  necessary  to  determine  whether 
it  possesses  regularity  of  shape. 

Uniformity  of  composition  can  be  tested  by  breaking  the  brick  and  examining 
the  surface  of  the  fracture.  This  should  present  a  compact  and  uniform  appearance, 
though  not  necessarily  a  close  and  fine  texture.  In  fact  some  authorities  consider 
a  coarse  texture  to  be  preferable.  Uniformity  of  composition  is  also  indicated  by  the 
giving  out  of  a  clear  ringing  sound  when  the  brick  is  struck  a  sharp  blow  with  the 
hammer. 

Facility  of  cutting  is  important  only  as  reducing  the  cost  of  labor  and  the  amount 
of  waste  during  the  operation  of  laying  the  brick,  and  while  desirable,  if  it  can  be  secured 
without  sacrificing  the  more  important  qualities,  it  cannot  be  considered  an  equivalent 
for  any  one  of  them. 

Shapes. — Fire-brick  are  made  in  standard  shapes  for  almost  any  construction  met 
with  in  practice.  The  regular  fire-brick  is  9X4^X2^  ins.  and  is  called  "  9  straight." 
They  are  made  1^  ins.  thick  instead  of  2£  ins.  and  are  called  "  split  brick."  Half  as 
wide,  2\  ins.  instead  of  4i  ins.,  are  called  "  soap  brick." 

To  make  arches  and  circles,  tapering  brick  are  made.  "  Key  brick  "  taper  from 
4^  ins.  at  one  end  to  4  ins.  or  smaller  at  the  other.  "  Arch  brick  "  taper  from  1\  ins. 
at  one  edge  to  2  ins.  or  smaller  at  the  other.  "  Wedge  brick  "  taper  from  2\  ins.  at 
one  end  to  2  ins.  or  smaller  at  the  other.  Besides  these  enumerated,  there  are  several 
other  standard  shapes  of  less  importance.  The  taper  brick  lay  circles  of  a  definite 
diameter.  -Circles  of  larger  diameter  can  be  laid  by  inserting  straight  brick  at  regular 
intervals. 

Fire-Brick  Joints. — The  joints  in  furnace  construction  should  be  as  close  as 
possible.  The  brick  should  rest  on  each  other,  the  fire-clay  should  only  close  the  crack 
remaining. 

The  following  is  an  analysis  of  several  heat-resisting  materials: 

Fire  Clay.  Asbestos.                   Magnesia  Brick. 

Silica 50%  41.5%                      1% 

Alumina 35%  2.0%  ' 

Water 15%  13.5% 

Magnesia 43.0%                     95% 

Iron  oxide ....                            4% 

From  this  it  is  evident  that  the  fire-resisting  qualities  are  not  dependent  on  any 
one  constituent. 

The  water  in  the  asbestos  is  partially  driven  out  at  a  temperature  below  red 
heat,  which  leaves  the  asbestos  so  brittle  that  it  may  be  reduced  to  a  powder  between 
the  thumb  and  finger. 


486 


GAS   PRODUCERS 


Notes. — Concerning  fire-brick,  the    Stoe-Fuller  Company  of   Cleveland,   0.,  say 
as  follows: 

A  standard  fire-brick  (straight)  weighs  7  Ibs. 

A  standard  silica  brick  weighs  6.2  Ibs. 

A  standard  magnesia  brick  weighs  9  Ibs. 

A  standard  chrome  brick  weighs  10  Ibs. 

A  silica  brick  expands  about  i  in.  per  ft.,  when  heated  to  2500°. 


O\Ho.l6Xe.w  \ 


L"  e; 


FIG.  241.— Fire-brick  Shapes. 

Clay  brick  expand  or  shrink,  dependent  upon  the  proportion  of  silica  to  alumina 
contained  in  the  brick;  but  most  fire-clay  brick  contain  alumina  sufficient  to  show 
some  shrinkage. 


MATERIALS:   FIRE  CLAY,  MASONRY,  WEIGHTS,  AND  ROPE        487 

One  cubic  foot  of  wall  requires  17  9-in.  bricks;  one  cubic  yard  requires  460.  Where 
keys,  wedges,  and  other  "  shapes  "  are  used,  add  10%  in  estimating  the  number  required. 

In  ordering  linings  customers  should  send  a  sketch  showing  outline  of  space  to  be 
occupied  by  brick-work,  or  inside  lines  with  thickness  of  walls  desired,  if  possible. 

Those  ordering  for  cupolas  and  stacks  should  be  careful  to  designate  in  order  both 
inside  and  outside  diameters  with  height. 

Silica  brick,  when  necessary,  should  be  laid  in  silica  cement  and  with  the  smallest 
joint  possible. 

To  secure  the  best  results,  fire-brick  should  be  laid  in  the  same  clay  from  which 
they  are  manufactured. 

One  ton  of  ground  clay  should  be  sufficient  to  lay  3000  ordinary  bricks. 

Ground  fire-brick  or  old  cupola  blocks  mixed  with  fire-clay  make  the  best  cupola 
daub  known. 

Be  careful  of  furnace  stays.     Silica  brick  expand.     Fire-clay  brick  shrink. 

Cool  your  furnaces  slowly. 

Cold  air  after  extreme  heat  is  the  hardest  test  on  good  fire-brick. 

The  minimum  carload  of  brick  or  clay  is  40,000  Ibs. 

Clay  for  shipment  by  boat  must  be  sacked  or  barreled. 


MASONRY  CONSTRUCTION 

Foundations. — The  stone  used  in  making  concrete,  according  to  Baker,  should 
be  clean  and  of  such  a  size  as  to  pass  in  any  direction  through  a  2^  in.  ring.  The  sand 
should  be  clean,  sharp,  and  coarse.  A  coarser  sand  than  that  used  for  making  mortar 
for  brick  can  be  employed  to  advantage  for  concrete.  The  proportions  of  the  ingredients 
depend  upon  the  strength  required  and  upon  the  average  size  of  the  pieces  of  stone 
and  of  the  grains  of  sand  used,  but,  under  ordinary  conditions,  the  following  proportions 
make  a  good  concrete:  1  part  of  Portland  cement,  2  parts  of  sand,  5  parts  of  broken 
stone. 

Broken  slag  or  coarse  gravel,  if  entirely  free  from  loam,  may  be  substituted  for 
the  broken  stone,  and  even  wrhen  the  latter  is  used,  one  or  two  parts  of  gravel  may  be 
added  to  the  mixture  as  given  above  without  decreasing  the  strength  of  the  concrete. 

For  mixing  the  concrete  a  platform  of  plank  about  10  X 16  ft.  should  be  laid.  If 
the  cement  and  sand  are  to  be  mixed  wet,  before  being  put  on  the  stone,  a  mortar  box 
should  be  placed  at  one  end  of  this  platform.  Measuring  boxes  to  measure  the  sand 
and  .broken  stone  should  be  provided.  These  are  made  with  four  sides  only,  being 
open  both  at  the  top  and  bottom.  They  may  be  either  of  one-barrel  capacity,  or  the 
one  for  the  sand  may  be  of  two-barrel  capacity  and  that  for  the  stone  of  five-barrel 
capacity,  if  the  mixture  is  to  be  as  above,  1  to  2  to  5,  and  should  be  provided  with 
handles  so  that  they  can  be  easily  lifted  and  set  to  one  side  after  the  material  has  been 
measured. 

The  sand  and  cement  should  be  measured  in  the  mortar  box  and  the  stone  measured 
and  placed  on  the  platform  at  the  foot  of  the  box  in  a  layer  about  6  to  8  ins.  thick. 
The  sand  and  cement  are  mixed,  the  stone  is  wet  and  the  mortar  spread  in  an  even  layer 


488  GAS   PRODUCERS 

on  top  of  it.  The  whole  mass  is  then  turned  over  a  sufficient  number  of  times  to  cause  the 
stone  and  moitar  to  be  thoroughly  mixed  together.  During  this  operation  care  should 
be  taken  to  really  turn  the  mass  instead  of  merely  shoveling  it  from  one  place  to  another. 
If  properly  handled  two  or  three  turnings  should  be  sufficient  to  produce  thorough 
mixture. 

Sometimes  the  cement  and  sand  are  mixed  and  spread  on  the  wet  stone  in  a  dry 
state,  the  whole  mass  then  being  turned  over  once  to  mix  the  stone  and  cement.  Water 
is  then  added  while  the  mass  is  being  turned  a  second  time,  and  the  turning  continued 
until  the  mixture  is  completed.  When  this  method  is  followed  there  is  no  need  of  a 
mortar  box,  the  cement  sand  being  mixed  on  the  platform. 

In  either  case  it  is  important  not  to  use  too  much  water,  since  wet  concrete  can 
not  be  compacted  by  ramming.  The  proper  quantity  of  water  to  be  used  should  be 
determined  by  experimenting  with  the  first  two  or  three  batches  made,  and  the  same 
amount  should  thereafter  be  used  for  each  batch  unless  the  temperature  and  humidity 
of  the  atmosphere  change  decidedly,  in  which  case  the  amount  of  water  will  have  to 
be  varied  to  suit  the  changed  conditions. 

When  thoroughly  mixed  the  concrete  should  be  put  in  barrows,  carried  to  the 
excavation,  dumped  quietly  into  place  and  then  rammed  until  the  moisture  appears 
on  the  surface.  In  no  case  should  it  be  thrown  into  place  with  shovels,  or  dropped 
from  any  height,  since  the  result  of  such  treatment  is  to  separate  the  stone  and  mortar 
and  prevent  the  formation  of  a  solid  block  of  concrete. 

In  preparing  the  excavation  the  earth  at  the  bottom  should  not  be  disturbed,  and 
should  it  be  loosened  it  must  be  rammed  until  firm.  Where  soft  or  yielding  earth 
or  sand  occurs,  the  bottom  should  be  planked  and  the  concrete  laid  on  this  planking. 
The  concrete  should  be  laid  in  layers  of  not  less  than  5  ins.  or  more  than  9  ins.  When 
joined  to  old  work  this  should  be  carefully  cleaned,  wetted  and  dusted  with  dry  cement. 

Mortar. — A  paste  of  good  hydraulic  cement  hardens  simultaneously  and  uniformly 
throughout  the  mass,  and  its  strength  is  impaired  by  an  addition  of  sand.  The 
relative  quantities  of  sand  and  cement  depend  somewhat  upon  the  condition  of  the 
ingredients  when  measured.  For  ordinary  use  it  is  customary  to  add  as  much  sand  as 
is  possible  without  making  the  mortar  porous.  The  proportions  may  vary  from  one  part 
of  cement  and  two  parts  of  sand  to  one  part  of  the  former  and  four  of  the  latter. 

The  proportion  of  sand  and  cement  are  generally  measured  by  volumes.  In 
actual  work  the  cement  is  usually  divided  in  barrels,  and  consequently  the  most 
convenient  unit  for  the  cement  is  the  commercial  barrel,  while  it  is  most  convenient 
to  measure  sand  loose. 

When  the  mortar  is  required  in  small  quantities,  as  for  use  in  ordinary  masonry, 
it  is  mixed  about  as  follows:  about  half  the  sand  to  be  used  in  a  batch  of  mortar  is 
spread  evenly  over  the  bed  of  the  mortar  box;  and  then  the  dry  cement  is  spread 
evenly  over  the  sand;  and  finally  the  remainder  of  the  sand  is  spread  on  top.  The  sand 
and  cement  is  then  mixed  with  a  hoe,  or  by  turning  and  re-turning  with  a  shovel.  It 
is  very  important  that  the  sand  and  cement  be  thoroughly  mixed. 

The. dry  mixture  is  then  shoveled  to  one  end  of  the  box,  and  the  water  is  poured 
into  the  other  end.  An  excess  of  water  is  better  than  a  deficiency,  particularly  when 
a  very  energetic  cement  is  used,  as  the  capacity  of  this  substance  for  solidifying  water 
is  great.  The  sand  and  cement  are  then  drawn  down  with  a  hoe,  small  quantities 


MATERIALS:   FIRE  CLAY,  MASONRY,  WEIGHTS,  AND  ROPE         489 

at  a  time,  and  mixed  with  the  water  until  enough  has  'been  added  to  make  a  good 
stiff  mortar.  This  should  be  vigorously  worked  with  a  hoe  for  several  minutes  to 
insure  a  complete  mixture.  The  mortar  should  then  leave  the  hoe  clean  when  drawn 
out  of  it,  and  very  little  should  stick  to  the  steel. 

Hydraulic  cements  set  better  and  attain  a  greater  strength  under  water  than 
in  the  open  air;  in  the  latter,  owing  to  the  evaporation  of  the  water,  the  water  is  liable 
to  dry  instead  of  setting.  This  difference  is  very  marked  in  hot  dry  weather.  If  cement 
mortar  is  to  be  exposed  to  the  air,  it  should  be  shielded  from  the  direct  rays  of  the 
sun,  and  kept  moist  by  sprinkling  or  otherwise. 

Grout  is  a  thin  or  liquid  mortar  of  lime  or  cement.  The  interior  of  a  wall  is  some- 
times laid  up  dry,  and  the  grout,  which  is  poured  on  top  of  the  wall  is  expected  to  find 
its  way  downwards  and  fill  up  all  voids,  thus  making  a  solid  mass  of  the  wall. 

Grout  should  never  be  used  when  it  can  be  avoided.  If  made  thin,  the  water 
only  slowly  dries  out  of  the  wall;  and  if  made  thick,  the  grout  fills  only  the  upper 
portion  of  the  wall.  To  get  the  greatest  strength,  the  mortar  should  have  only  enough 
water  to  make  a  stiff  paste — the  less  water  the  better.  If  the  mortar  is  stiff,  the  brick 
or  stone  should  be  dampened  before  laying;  else  the  brick  will  absorb  the  water  from 
the  mortar  before  it  can  be  set,  and  thus  destroy  the  adhesion  of  the  mortar.  (Baker's 
"Treatise  on  Masonry  Construction.") 

Cement  mortar  should  be  used  in  all  thick  walls,  in  all  masonry  subject  to  vibration, 
and  in  masonry  exposed  to  water  or  moisture.  It  should  be  used,  therefore,  in  the 
foundations  of  buildings  and  machinery,  and  in  holder  tank  walls.  Unlike  lime  mortar, 
good  cement  mortar  increases  in  strength  with  age  even  under  water  or  exposed  to 
moisture — exposure  to  which  will  disintegrate  lime  mortar  rapidly. 

When  cement  is  cheap  it  is  a  question  whether  it  could  not  be  substituted  for 
lime  in  the  mortar  for  even  ordinary  masonry.  Its  cost  for  such  purpose  when  great 
strength  is  not  required  may  be  reduced  without  serious  loss  of  strength  by  the  addition 
to  the  mortar  of  from  20  to  25%  of  lime  paste. 

Laying  Brick. — Baker's  "  Treatise  on  Masonry  Construction  "  gives  the  following 
instructions:  "  Brick  should  not  be  merely  laid,  but  every  one  should  be  rubbed 
and  pressed  down  in  such  a  manner  as  to  force  the  mortar  into  the  pores  of  the  bricks 
and  produce  the  maximum  adhesion;  with  a  quick  setting  cement  this  is  still  more 
important  than  with  lime  mortar.  For  the  best  work  it  is  specified  that  the  brick 
should  be  laid  with  a  'shove  joint;'  that  is,  that  the  brick  should  first  be  laid  so  as 
to  project  over  the  one  below,  and  be  pressed  into  the  mortar,  and  then  be  shoved  into 
its  final  position.  Since  bricks  have  great  avidity  for  water,  it  is  best  to  dampen 
them  before  laying.  If  the  mortar  is  stiff  and  the  brick  dry,  the  latter  absorb  the 
water  so  rapidly  that  the  mortar  does  not  set  properly  and  will  crumble  in  the  fingers 
when  dry.  Neglect  in  this  particular  is  the  cause  of  most  of  the  failures  of  brick 
work.  .  .  .  Wetting  the  brick  before  laying  will  also  remove  the  dust  from  the 
surface,  which  otherwise  would  prevent  perfect  adhesion.  " 

Brick  Tank  Wall. — There  is  among  constructors  a  difference  of  opinion  as  to 
how  the  bricks  should  be  put  into  the  wall.  The  following  is  from  a  man  who  has 
had  considerable  experience  in  tank  work,  and  whose  tanks  have  been  tight : 

"  The  bricklayer  should  put  only  enough  mortar  on  the  wall  to  embed  one 
brick,  place  the  brick  in  the  mortar,  then  give  it  a  sliding  motion  in  two  directions  to 


490  GAS   PRODUCERS 

fill  the  joints  on  one  end  and  on  one  side,  and  to  expel  the  air  from  under  the  brick. 
The  mortar  should  then  be  cut  of  the  top  and  returned  to  the  board.  It  is  impos- 
sible to  accurately  describe  how  to  push  brick;  the  only  way  is  to  get  a  brick  mason 
that  can  and  will  do  this  kind  of  work,  and  have  him  instruct  each  mason  that  is 
taken  on  the  job,  how  the  work  is  to  be  done." 

An  advocate  of  grouting,  who  has  been  perfectly  successful  in  tank  work,  writes 
as  follows:  "  The  thickness  of  joint  being  decided  upon,  the  outside  and  inside 
circle  should  be  laid  up  five  courses,  making  a  trough  for  filling  in.  Spread  thick  mortar 
in  the  bottom  of  this  trough  and  lay  the  brick  in  this  mortar,  care  being  taken  that 
the  brick  shall  be  put  down  in  such  a  manner  as  to  drive  all  the  air  out  as  they  fall 
into  place.  This  makes  a  full  joint  under  the  brick.  Then  grout  with  mortar  to  be 
thrown  over  the  tops  of  these  bricks  from  a  bucket  in  the  same  manner  as  coke  is 
quenched,  the  mason  using  his  trowel  to  fill  in  any  joints  that  are  not  filled  by  spread- 
ing the  mortar  in  this  way.  On  this  layer  of  bricks  spread  another  layer  of  stiff  mortar 
and  lay  another  course  of  brick,  grouting  in  these  as  in  the  former  case.  Care  should 
be  taken  to  arrange  headers  and  stretchers,  so  that  there  will  be  a  good  bond. 

"  By  pursuing  this  method,  a  fair  mason  can  lay  from  1800  to  2200  bricks  per 
day;  2100  to  2200  bricks  were  laid  per  day,  per  mason,  under  my  supervision.  The 
brick  for  the  inside  and  outside  circle  should  be  wetted  with  a  hose.  The  brick  for 
filling  in  should  be  throughly  wetted,  and  I  would  advise  having  a  number  of  tubs 
placed  at  intervals  on  the  scaffold,  and  the  brick  thoroughly  soaked  with  water  in 
these  tubs  before  being  put  in  the  wall;  in  fact,  the  brick  should  be  taken  from  these 
tubs  and  placed  in  the  wall  without  giving  them  time  to  dry." 

There  can  be  no  doubt  that  entirely  satisfactory  tanks  have  been  built  by  each 
method.  It  is  probably  equally  true  that  a  mason  can  lay  from  200  to  400  more 
bricks  a  day  by  adopting  the  second  or  grouting  method.  It  is  also  probably  true 
that  more  close  supervision  is  required  to  obtain  good  work  with  the  grouting  system. 

Baker's  "  Treatise  on  Masonry  Construction,"  page  37,  contains  the  following 
paragraph : 

Requisites  for  Good  Brick. — 1.  "  A  good  brick  should  have  plane  faces,  parallel 
sides,  and  sharp  edges  and  angles.  2.  It  should  be  of  fine,  compact,  uniform  texture; 
should  be  quite  hard  and  should  give  a  clear  ringing  sound  when  struck  a  sharp  blow. 
3.  It  should  not  absorb  more  than  one-tenth  of  its  weight  of  water.  4.  Its  specific 
gravity  should  be  two  or  more.  5.  The  crushing  strength  of  half  brick  when  ground 
flat  and  pressed  between  thick  metal  plates,  should  be  at  least  7000  Ibs.  per  square 
inch." 

Regularity  of  shape  can  be  determined  by  inspection  of  the  brick,  as  can  also,  to 
a  certain  extent,  compactness  and  uniformity  of  texture.  The  absorptive  power, 
which  effects  the  durability  of  the  brick,  especially  as  regards  its  resistance  to  frost, 
can  be  determined  by  weighing  the  brick  after  it  has  been  kept  exposed  in  a  room 
under  ordinary  atmospheric  conditions  for  a  week  and  then  again  after  it  has  been 
immersed  in  water  for  from  40  to  48  hours,  and  allowed  to  dry  until  all  the  water  on 
the  surface  has  evaporated,  the  difference  between  the  first  weight  and  the  second 
one  being  the  weight  of  water  absorbed.  The  smaller  the  amount  of  water  so  absorbed 
the  greater  will  be  the  durabiility  of  the  brick. 

In  determining  the  crushing  strength  of  the  brick  different  methods  are  followed. 


MATERIALS:   FIRE  CLAY,  MASONRY,  WEIGHTS,  AND  ROPE        491 

Sometimes  half  brick  are  tested  and  sometimes  whole  ones.  In  some  cases  the  surfaces 
to  be  subjected  to  the  pressure  are  ground  accurately  to  planes  parallel  to  each 
other,  •while  in  other  cases  the  surfaces  are  leveled  up  by  putting  on  a  thin  coat  of 
plaster  of  paris,  and  in  still  others  the  bricks  are  put  into  a  testing  machine  in  the 
rough  state.  The  best  practice  is  to  either  grin  I  the  faces  or  to  level  them  up  by 
the  use  of  plaster  of  paris,  so  that  the  pressure  is  applied  equally  all  over  the  surface. 
These  crushing  tests  are  usually  made  in  a  hydraulic  press  provided  with  cast  iron 
pressing  surfaces  which  are  self  adjusting. 

The  test  for  transverse  strength  is  about  the  most  valuable  that  can  be  given  to 
brick  to  determine  its  practical  value.  It  is  made  by  supporting  the  brick  on  two 
supports  with  thin  edges  placed  the  required  distance  apart,  and  then  loading  it  in 
the  center  with  a  load  which  is  applied  by  a  beam  with  a  thin  edge  bearing  on  the 
brick,  the  load  required  to  break  the  brick  being  carefully  determined.  The 
modulus  of  rupture  as  determined  by  this  test  should  be  at  least  1000  Ibs.  per  square 
inch. 

Brick- Work  Measurement. — Brick-work  is  generally  measured  by  1000  bricks  laid 
in  the  wall.  In  consequence  of  variations  in  size  of  bricks,  no  rule  for  volume  of  laid 
brick  can  be  exact;  the  following  scale  is,  however,  a  fair  average. 

7  bricks  to  a  superficial  square  foot  of  4-in.  wall  =  40  Ibs. 
14  9-in.  wall  =  94    " 

21  "  "  13-in.  wall  =  121  " 

28  "  "         "        18-in.  wall  =168" 

35  "  "       22-in.  wall  =  210" 

Corners  are  not  measured  twice  as  in  stone  work.  Openings  over  2  feet  square 
are  deducted.  Arches  are  counted  from  the  spring.  Fancy  work  is  counted  1^ 
bricks  for  one.  Pillars  are  measured  on  their  face  only. 

A  cubic  yard  of  mortar  requires  1  cubic  yard  of  sand  and  9  bushels  of  lime, 
and  will  fill  30  hods. 

One  thousand  bricks,  closely  stacked,  occupy  about  56  cubic  feet. 

One  thousand  old  bricks,  cleaned  and  loosely  stacked  occupy  about  72  cubic 
feet. 

One  superficial  foot  of  gauged  arches  requires  10  bricks. 

Stock  bricks  commonly  measure  8|  ins.  X4|  ins.  X2f  ins.,  and  weigh  from  5  to 
6  Ibs.  each. 

Paving  bricks  should  measure  9  ins.  X4^  ins.  X  If  ins.,  and  weigh  about  4£  Ibs. 
each. 

One  yard  of  paving  requires  36  stock  bricks,  of  above  dimensions,  laid  flat,  or 
52  on  edge;  and  35  paving  bricks  laid  flat,  or  82  on  edge. 

In  brick  masonry  about  20  bricks  are  calculated  per  cubic  foot  of  the  larger  size, 
such  as  prevails  in  the  Western  and  Middle  States,  and  about  22  bricks  of  the  smaller 
size,  which  is  chiefly  used  in  the  East.  Of  the  former  about  7  bricks  are  allowed  for 
each  square  foot  superficial  area  of  the  wall  (one-half  brick  thick)  and  of  the  latter 
7.5  bricks. 

Stone- Work. — Stone  walls  are  measured  by  the  perch  (24f  cu.ft.).  Openings 
less  than  3  ft.  wide  are  counted  solid;  over  3  ft.  deducted,  but  18  ins.  are  added  to 


492  GAS   PRODUCERS 

the  running  measure  for  each  jamb  built.  Arches  are  counted  solid  from  their  spring. 
Corners  of  buildings  are  measured  twice.  Pillars  less  than  3  ft.  are  counted  on  three 
sides  as  lineal,  multiplied  by  fourth  side  and  depth. 

It  is  customary  to  measure  all  foundation  and  dimension  stone  by  the  cubic  foot. 
Water  tables  and  base  courses  by  lineal  feet.  All  sills  and  lintels  or  ashlar,  by  super- 
ficial feet,  and  no  wall  less  than  18  ins.  thick. 

The  greatest  safe  load  per  superficial  foot  on 

Granite  piers =40    tons 

Limestone  piers =25     " 

Sandstone  piers =15     " 

Brick- work  in  cement =   3     " 

Rubble  masonry =   2     " 

Lime  concrete  foundations =   2^   " 

According  to  Siebel  brick  walls  will  safely  withstand  a  load  of  from  5  to  6  tons 
per  sq.ft.  according  to  quality;  rubble  walls  in  courses  from  6  to  12  tons;  dimension 
stones  (sand  or  limestone)  12  to  18  tons,  and  granite  from  18  to  36  tons.  Concrete 
walls  from  6  to  8  tons  per  sq.ft.;  hollow  tiles  about  5  tons  per  sq.ft.  actual  bearing 
surface. 

The  height  of  brick  or  stone  piers  should  not  exceed  12  times  their  least  thickness 
at  base. 

"  Brick-work  is  not  as  strong  as  ashlar  masonry,  but  costs  less,  while  it  is  stronger 
and  costs  more  than  ordinary  rubble."  (Baker's  "Masonry  Consst ruction.") 

The  best  grades  of  stone  have  greater  compressive  strength  and  durability  than 
brick  and  are  better  for  massive  work,  such  as  heavy  abutments  and  piers  for  bridges 
and  large  foundations.  In  comparatively  thin  walls,  however,  a  better  bond  can  be 
obtained  with  brick  than  with  stone,  and  in  such  work  the  use  of  stone  has  been 
entirely  abandoned  in  favor  of  brick  except  when  the  stone  is  employed  for  the  purpose 
of  ornament.  In  the  class  of  buildings  needed  about  gas  works  brick  masonry  is  given 
the  preference  to  stone  masonry,  for  the  reasons  stated  in  the  quotation  given  above, 
except  in  places  where  good  stone  can  be  obtained  either  on  or  very  close  to  the  site 
of  the  works. 

Cement. — Rosendale  or  Utica  cement,  also  called  natural  cement,  is  made  from 
limestones  composed  of  carbonate  of  lime,  carbonate  of  magnesia  and  clay.  The 
limestone  is  burned  in  a  kiln  and  then  ground  to  a  fine  powder.  "  Any  magnesian 
limestone  containing  as  high  as  60%  of  carbonate  of  magnesia,  may  be  presumed  to 
be  capable  of  yielding  hydraulic  cement  of  greater  or  less  value,  if  properly  burned, 
no  matter  whether  clay  be  present  or  not." 

Cement  should  be  tested  for  fineness,  liability  to  cracking  and  tensile  strength. 

1.  Fineness.     From  90  to  95%  of  the  cement  should  pass  though  a  sieve  of  250 
meshes   to    the    inch.     Other   qualities   being  equal,  the  finer  a  cement  is  ground  the 
greater  is  its  value. 

2.  Checking  or  cracking.     The  test  for  checking  or  cracking  is  an  important  one, 
and  though  simple,  should  never  be  omitted.     It  is  as  follows:    "Make  two  cakes  of 
neat  cement  2  or  3  ins.  in  diameter,  about  \  in.  thick,  with  thin  edges.     Note  the  time 


MATERIALS:   FIRE  CLAY,  MASONRY,  WEIGHTS,  AND  ROPE        493 

in  minutes  that  these  cakes,  when  mixed  with  the  water  to  the  consistency  of  a  stiff 
plastic  mortar,  take  to  set  hard  enough  to  stand  the  wire  test  recommended  by  Gen. 
Gillmore,  iVin.  diameter  wire  if  loaded  with  ^  Ib.  and  -jV^11-  when  loaded  with  1  lb. 
One  of  these  cakes  when  hard  enough  should  be  put  in  water  and  examined  from  day 
to  day  to  see  if  it  becomes  contorted  or  if  cracks  show  themselves  at  the  edges,  such 
contortions  or  cracks  indicating  that  the  cement  is  unfit  for  use  at  that  time.  In  some 
cases  the  tendency  to  crack,  if  caused  by  the  presence  of  too  much  unslaked  lime,  will 
disappear  with  age.  The  remaining  cake  should  be  kept  in  the  air  and  its  color 
observed,  which,  for  a  good  cement,  should  be  uniform  throughout  (yellowish  blotches 
indicating  a  poor  quality),  the  natural  cements  being  light  or  dark  according  to  the 
character  of  the  rock  of  which  they  are  made.  The  color  ^of  the  cements  when  left 
in  the  air  indicates  the  quality  much  better  than  when  they  are  put  in  water. 

3.  Tensile  strength.  The  tests  should  be  applied  to  the  cement  as  offered  for 
sale.  The  following  table  gives  the  average  range  of  tensile  strength  per  square  inch 
which  some  good  cements  have  attained: 

AVERAGE  TENSILE   STRENGTH   IN   POUNDS   PER   SQUARE   INCH 

AGE  or  MORTAR  WHEN  TESTED.  ROSENDALE  CEMENT. 

Neat  Cement.  Min.  Max. 

1  day — 1  hour  (or  until  set)  in  air,  the  remainder  of  the  time  in  water 40  80 

1  week — 1  day  in  air,  the  remainder  of  time  in  water 60  100 

4  weeks — 1  day  in  air,  the  remainder  of  time  in  water 100  150 

1  year — 1  day  in  air,  the  remainder  of  time  in  water 300          400 

ONE  PART  CEMENT  AND  ONE  PART  SAND. 

1  week — 1  day  in  air,  the  remainder  of  time  in  water 30  50 

4  weeks — 1  day  in  air,  the  remainder  of  time  in  water 50  80 

1  year — 1  day  in  air,  the  remainder  of  time  in  water 200  300 

"  If  satisfactory  results  are  obtained  with  a  full  dose  of  sand,  the  trials  need  go 
no  further.  If  not  the  coarser  particles  should  be  excluded  by  using  a  No.  100  sieve, 
in  order  to  determine  approximately  the  grade  the  cement  would  take  if  ground  fine, 
for  fineness  is  always  attainable,  while  inherent  merit  may  not  be. 

"  Weight.  For  any  particular  cement  the  weight  varies  with  the  degree  of  heat 
in  burning,  the  degree  of  fineness  in  grinding,  and  the  density  of  packing.  Other 
things  being  the  same,  the  harder  burned  varieties  are  the  heavier.  The  finer  a  cement 
is  ground  the  more  bulky  it  becomes,  and  consequently  the  less  it  weighs.  Hence, 
the  light  weight  may  be  caused  by  laudable  fine  grinding  or  by  objectionable  under- 
burning. 

"  The  weight  per  unit  of  volume  is  usually  determined  by  sifting  the  cement 
into  a  measure  as  lightly  as  possible,  and  striking  the  top  level  with  a  straight  edge. 
In  careful  work  the  height  of  fall  is  specified.  The  weight  per  cubic  foot  is  neither 
exactly  constant  nor  can  it  be  determined  precisely,  and  for  the  practical  purpose  of 
the  user  is  of  very  little  service  in  determining  the  value  of  a  cement.  However, 
it  is  often  specified  as  one  of  the  requirements  to  be  fulfilled. 

"  The  weight  of  Rosendale  cement,  determined  by  sifting  the  cement  with  a  fall 
of  three  feet  into  a  box  having  a  capacity  of  one-tenth  of  a  cubic  foot,  is  49  to  56  Ibs. 
per  cubic  foot.  The  difference  in  weight  for  any  particular  kind  is  mainly  due  to  a 
difference  in  fineness. 


494  GAS   PRODUCERS 

"Ulster  County  Rosendale  cement  weighs  300  Ibs.  per  barrel  net;  Akron, 
Milwaukee,  Utica,  and  Louisville  Rosendales  weigh  265  Ibs.  per  barrel  net.  (See 
Baker,  "  Masonry  Construction.") 

Concrete  Walls. — Concrete  walls  for  houses  are  built  of  1  of  cement  to  6  or  7  of 
broken  stone,  shingle,  gravel,  or  slag.  The  substance  mixed  with  the  cement  must 
be  free  from  loam,  fine  sand,  clay,  or  dirt  of  any  kind.  To  prevent  the  cement  from 
adhering  to  the  planks  of  the  mold,  apply  freely  to  them  with  a  brush,  soap  boiled  to 
the  consistency  of  paint. 

WEIGHTS 


Names  of  Substances.  Average  Weight, 

Pounds. 

Anthracite,  solid,  of  Pennsylvania 93 

Anthracite,  broken,  loose 54 

Anthracite,  broken,  moderately  shaken 58 

Anthracite,  heaped  bushel,  loose (80) 

Ash,  American  white,  dry 38 

Asphaltum 87 

Brass  (Copper  and  Zinc),  cast 504 

Brass,  rolled 524 

Brick,  best  pressed 150 

Brick,  common  hard 125 

Brick,  soft  inferior 100 

Brick- work,  ordinary 112 

Brick-work,  pressed  brick 140 

Cement,  hydraulic,  ground,  loose,  American,  Rosendale  56 

Cement,  hydraulic,  ground,  loose,  American,  Louisville .  50 

Cement,  hydraulic,  ground,  loose,  English,  Portland  ...  90 

Cherry,  dry 42 

Chestnut,  dry 41 

Coal,  bituminous,  solid 84 

Coal,  bituminous,  broken,  loose 49 

Coal,  bituminous,  heaped  bushel,  loose (74) 

Coke,  loose,  of  good  coal 27 

Coke,  loose,  heaped  bushel . .  (38) 

Copper,  cast 542 

Copper,  rolled 548 

Earth,  common  loam,  dry,  loose 76 

Earth,  common  loam,  dry,  moderately  rammed 95 

Earth,  as  a  soft  flowing  mud 108 

Ebony,  dry 76 

Elm,  dry 35 

Flint ••  162 

Glass,  common  window 157 

Gneiss,  common 168 


MATERIALS:  FIRE  CLAY,  MASONRY,  WEIGHTS,  AND  ROPE        495 

WEIGHT  PER  CUBIC  FOOT  OF  MATERIALS— Continued 

Names  of  Substances.  Average  Weight, 

Pounds. 

Gold,  cast,  pure,  or  24  carat 1204 

Gold,  pure,  hammered 1217 

Granite 170 

Gravel,  about  the  same  as  sand,  which  see. 

Hemlock,  dry 25 

Hickory,  dry 53 

Hornblende,  black 203 

Ice 58.7 

Iron,  cast 450 

Iron,  wrought,  purest 485 

Iron,  wrought,  average 480 

Ivory 114 

Lead 711 

Lignumvitae,  dry 83 

Lime,  quick,  ground,  loose,  or  in  small  lumps 53 

Lime,  quick,  ground,  loose,  thoroughly  shaken 75 

Lime,  quick,  ground,  loose,  per  struck  bushel 66 

Limestones  and  marbles 168 

Limestones  and  marbles,  loose,  in  irregular  fragments  .  .       96 

Mahogany,  Spanish,  dry 53 

Mahogany,  Honduras,  dry 35 

Maple,  dry 49 

Masonry,  of  granite  or  limestone,  well  dressed 165 

Masonry,  of  mortar  rubble 154 

Masonry,  dry  (well  scabbled) 138 

Masonry,  sandstone,  well  dressed 144 

Mercury,  at  32°  F 849 

Mica 183 

Mortar,  hardened 103 

Mud,  dry,  close 80-1 10 

Mud,  wet,  fluid,  maximum 120 

Oak,  live,  dry 59 

Oak,  white,  dry 52 

Oak,  other  kinds 32-45 

Petroleum 55 

Pine,  white,  dry 25 

Pine,  yellow,  northern 34 

Pine,  yellow,  southern 45 

Platinum 1342 

Quartz,  common,  pure 165 

Rosin 69 

Salt,  coarse 45 

Salt,  fine  for  table  use 49 

Sand,  well  shaken 99-117 


496 


WEIGHT  PER  CUBIC  FOOT  OF  MATERIALS— Continued 

Names  of  Substances.  Average  Weight, 

Pounds. 

Sand,  perfectly  wet 120-140 

Sandstones,  fit  for  building 151 

Shales,  red  or  black 162 

Silver 655 

Slate 175 

Snow,  freshly  fallen 5-12 

Snow,  moistened  and  compacted  by  rain 15-50 

Steel 490 

Sulphur 125 

Water,  pure  rain,  or  distilled  at  60°  F 62| 

Green  timbers  usually  weigh  from  one-fifth  to  one-half  more  than  dry. 

WEIGHTS  OF  FUEL  AND   MORTAR  MATERIALS 

Anthracite,  broken,  1  cu.ft 54      Ibs. 

Coke,  broken,  1  cu.ft 31.5" 

Bituminous,  broken,  1  cu.ft 49       " 

Charcoal,  broken,  cu.ft 18.5" 

1  ton  anthracite  (loose) 40-43  cu.ft. 

1  ton  coke  (2240  Ibs.) 70.9    " 

1  ton  bituminous  coal 43-48    ' ' 

1  ton  charcoal  (2240  Ibs) 123      " 

Cement,  Rosendale,  1  bu 70  Ibs. 

Cement,  Louisville,  1  bu 62  " 

Cement,  Portland,  1  bu 96  " 

Lime  (loose),  1  bu 70  " 

Lime  (shaken),  1  bu 80  " 

Sand  (avg.)  98  Ibs.  per  cu.ft.,  1  bu 122.5  pounds. 

Sand,  18.29  bu.  =  l  ton;    1.181  tons  =  l  cu.yd. 


SHEET   IRON   WEIGHTS 

Weight    of    a    Square    Foot    Rolled    to    Partridge    Gauge. — Where 
required,  take  thickness  in  thousandths  of  an  inch,  or  weight  per  foot: 


accuracy   is 


Number  of 
Gauge. 


1 
2 

3-1 

4 
5 
6 

7 
8 


Weight 
per  Foot. 


11.25 
10.625 
10 

9  375 
8.75 
8.125 
7.5 
6.875 


Number  of 
Gauge. 


9 
10 
H 
12 
13 
14 
15 


Weight  of 
per  Foot. 


6.25 


625 

375 

75 
125 


2.8125 


Number  of 
Gauge. 


17 
18 
19 
20 
21 
22 
23 


Weight 
per  Foot. 


2.5 

2 . 1875 

1.875 

1.7188 

1.5625 

1.4063 

1.25 

1.12 


Number  of 
Gauge. 


24 
25 

26 
27 
28 
29 
30 


Weight 
per  Foot. 


1 

0.9 

0.8 

0.72 

0.64 

0.56 

0.5 


MATERIALS:    FIRE  CLAY,  MASONRY,  WEIGHTS,  AND  ROPE       497 


PLATE-IRON  WEIGHTS 
WEIGHT  PER  SQUARE  FOOT 


Thickness  in  Inches. 

Weight,  Pounds. 

Thickness  in  Inches. 

Weight,  Pounds. 

3^=0.03125 

1.25 

A  =  0.3125 

12.58 

^=0.0625 

2.519 

1  =  0.375 

15.10 

&  =  0.0937 

3.788 

A  =  0.4375 

17.65 

I  =  0.125 

5.054 

4  =  0.5 

20.20 

,£  =  0.1562 

6.305 

A  =  0.5625 

22.76 

^  =  0.1875 

7.578 

t  =0.625 

25.16 

&  =0.2187 

8.19 

1=0.75 

30.20 

i  =  0.25 

10.09 

1  =  0.875 

35.30 

^  =  0.2812 

11.38 

1  =  1 

40.40 

To  ascertain  the  weight  of  plate  iron  for  rectangular  sheets: 

Rule. — Multiply  the  product  of  length  by  breadth  in  inches,  by  one  of  the  following 
decimals,  according  to  thickness,  and  the  product  will  be  the  weight  required. 


A 

I 

A 


thick  X  0.0526 
X0.07 
X 0.0874 
X 0.1048 
X 0.1226 
X0.14 


A  thickXO.158 
|     "     X0.1748 
J     "     X0.2096 
|     "     X0.245f 
1     "     X0.28 


WEIGHT   OF  CIRCULAR  BOILER   HEADS 


Diameter 
in 

Inches. 

THICKNESS  OF  IRON,  INCHES. 

A 
Pound. 

t 

Pound. 

A 

Pound. 

* 

Pound. 

A 

Pound. 

i 

Pound. 

A 
Pound. 

16 

11 

14 

18 

21 

25 

28 

32 

18 

13 

18 

22 

27 

31 

36 

40 

20 

17 

22 

27 

33 

38 

44 

50 

22 

20 

27 

33 

40 

47 

54 

60 

24 

24 

32 

40 

47 

55 

64 

71 

26 

28 

37 

46 

56 

64 

75 

84 

28 

32 

43 

53 

65 

75 

86 

97 

30 

37 

50 

62 

74 

87 

100 

112 

32 

42 

56 

70 

84 

99 

112 

127 

34 

48 

64 

79 

96 

111 

128 

143 

36 

54 

71 

89 

108 

125 

142 

161 

38 

60 

79 

99 

120 

139 

158 

179 

40 

66 

88 

110 

132 

154 

176 

198 

42 

73 

97 

121 

146 

170 

194 

220 

44 

80 

107 

133 

160 

187 

214 

240 

46 

88 

117 

145 

176 

204 

234 

262 

48 

95 

127 

158 

190 

222 

254 

286 

50 

103 

138 

172 

206 

241 

276 

310 

52 

112 

149 

186 

224 

260 

298 

335 

54 

121 

160 

200 

242 

281 

320 

362 

56 

130 

172 

214 

260 

302 

344 

389 

58 

139 

185 

231 

278 

324 

370 

41.7 

60 

149 

198 

247 

298 

336 

396 

446 

498 


GAS   PRODUCERS 
WEIGHT   OF   TANK  RIVETS— NUMBER  TO  THE   POUND 


£-inch  Diameter. 

^-inch  Diameter. 

j-inch  Diameter. 

i^-inch  Diameter. 

f-inch  Diameter. 

Ts-inch  Diain. 

>c 

M 
C 

5 

Flat  and 
Round 
Heads. 

Counter- 
sunk. 

Flat  and 
Round 
Heads. 

Counter- 
sunk. 

Flat  and 
Round 
Heads. 

Counter- 
sunk. 

Flat  and 
Round 
Heads. 

Counter- 
sunk. 

Flat  and 
Round 
Heads. 

Coun- 
ter- 
sunk. 

Flat 
Heads. 

Coun- 
ter- 
sunk. 

1 

204 

280 

165 

230 

103 

155 

67 

89 

o 

A 

190 

250 

153 

200 

92 

128 

58 

78 

35 

J.O 

4 

175 

222 

135 

172 

81 

108 

50 

69 

31 

45 

1 

160 

200 

118 

148 

71 

93 

44 

60 

27 

39 

0 

i 

144 

180 

103 

129 

63 

80 

39 

53 

24 

34 

17 

22 

i 

135 

165 

92 

114 

56 

70 

35 

47 

22 

30 

15 

19 

i 

126 

150 

84 

102 

50 

62 

32 

42 

20 

27 

14 

174 

H 

116 

140 

77 

93 

46 

56 

30 

37 

19 

24 

13 

16 

H 

108 

130 

72 

85 

43 

51 

28 

34 

18 

22 

12 

15 

H 

100 

120 

67 

78 

40 

47 

29 

31 

17 

21 

1U 

144 

H 

93 

112 

62 

72 

37 

44 

24 

29 

16 

20 

11 

14 

if 

87 

104 

58 

67 

34 

41 

22 

27 

15          19 

10* 

134 

i! 

81 

96 

54 

62 

32 

38 

21 

25 

14          18 

10 

12J 

H 

51 

58 

30 

36 

20 

24 

13          17 

94 

1H 

2 

48 

54 

29 

34 

19 

23 

12          16 

9 

11 

2i 

43 

49 

27 

32 

17 

21 

11          15 

81 

104 

24 

39 

45 

24 

29 

16 

20 

10          14 

7! 

9| 

2| 

35 

40 

22 

26 

14 

17 

9          12 

71 

9 

3 

31 

36 

20 

24 

13 

16 

8          11 

Of 

84 

3* 

18 

21 

11 

14 

7          10 

6 

7* 

"  J 

4 

16 

20 

10 

13 

6            9 

5 

•   J 

64 

NUMBER  CONE   HEAD   RIVETS   IN    100   POUNDS 


Lengths 

f-inch. 

i^-inch. 

i-inch. 

iVinch. 

f-inch. 

tt-inefa. 

J-inch. 

t-inch. 

1 

1965 

1429 

1092 

944 

'  665 

£ 

1848 

1335 

1027 

846 

597 

1 

1692 

1222 

940 

763 

538 

450 

H 

1512 

1092 

840 

727 

512 

415 

U 

1437 

1036 

797 

691 

487 

389 

356 

228 

if 

1368 

988 

760 

653 

460 

370 

329 

211 

14 

1300 

949 

730 

624 

440 

357 

280 

180 

if 

1260 

924 

711 

596 

420 

340 

271 

174 

if 

1200 

900 

693 

553 

390 

325 

262 

169 

1* 

1156 

840 

648 

532 

375 

312 

257 

165 

2 

1100 

789 

608 

511 

360 

297 

243 

156 

2* 

1031 

744 

575 

502 

354 

289 

237 

152 

21 

999 

721 

555 

491 

347 

280 

232 

149 

24 

945 

682 

525 

475 

335 

260 

220 

141 

2| 

900 

650 

500 

443 

312 

242 

208 

133 

3 

828 

598 

460 

411 

290 

224 

197 

127 

3* 

779 

562 

433 

379 

267 

212 

180 

115 

34 

743 

536 

413 

352 

248 

201 

169 

108 

31 

715 

513 

395 

341 

241 

192 

160 

102 

4 

326 

230 

184 

158 

99 

41 

312 

220 

177 

150 

96 

44 

298 

210 

171 

146 

94 

4| 

284 

200 

166 

138 

89 

5 

270 

190 

164 

135 

87 

MATERIALS:   FIRE  CLAY,  MASONRY,  WEIGHTS,  AND  ROPE 
WEIGHT   OF   CORRUGATED   IRON  ROOFING 


499 


British  Wire 
Gauge. 

Pounds  per 
Square  of  100 
Square  Feet, 
Plain  or  Painted. 

British  Wire 
Gauge. 

Pounds  per 
Square  of  100 
Square  Feet, 
Plain  or  Painted. 

No.  28 

97  Ibs. 

No.  20 

185  Ibs. 

"     2ti 

105  " 

"     18 

270  " 

"     24 

128  " 

"     16 

340  " 

"     22 

150  " 

Galvanized  iron  weighs  from  5  to  15%  heavier  than  plain,  according  to  the  number 
B.W.G.  For  a  good  durable  roof,  lighter  than  No.  22  is  not  recommended.  Corrugated 
iron  is  usually  made  in  sheets  from  6  to  8  ft.  long,  and  from  2  to  3  ft.  wide. 

The  sheets  when  used  for  roofing  should  overlap  about  6  ins.  in  girth,  and  be  double- 
riveted  at  the  joints.  One-third  of  the  net  width  may  be  allowed  approximately  for 
lappage  and  corrugations.  From  2£  to  3£  Ibs.  of  rivets  will  be  required  for  a  square. 

DECREASE    OF    STRENGTH    OF    WROUGHT    IRON    AT    HIGH    TEMPERATURES 
(Experiments  by  W.  Johnson  and  Benj.  Reeves,  Com.  Franklin  Inst.,  1839.) 


Temperature. 

Decrease  Per  Cent 
of  Maximum 

Temperature. 

Decrease  Per  Cent 

Centigrade. 

Fahrenheit. 

Tenacity. 

Centigrade. 

Fahrenheit. 

Tenacity. 

271° 

520° 

0.0738 

500° 

932° 

0.3324 

313 

0.0899 

554 

0.4478 

332 

630 

0  .  1047 

599 

0.5514 

350 

0.1155 

624 

1154 

0.6 

389 

732 

0.1491 

669 

0.6622 

440 

0.2010 

708 

1306 

0.7001 

ROPE 

Strength  of  Manila  and  Hemp  Rope. — A  well  known  authority  says:  "The 
strength  of  rope' is  very  irregular,  much  depending  on  the  quality  of  the  fiber  used  and 
the  solidity  in  which  the  rope  is  put  together.  For  instance,  3^-in.  circumference  soft- 
laid  rope  will  not  measure  over  3  ins.  circumference  hard-laid. 

"Our  tests  of  the  various  makes  of  rope  from  the  manila  fiber  show  about  the 
following  average  maximum  strength: 

3-in.  circumference  soft-laid 7300  Ibs. 

3-in.  circumference  medium-laid 8000  Ibs. 

3-in.  circumference  hard-laid 9000  Ibs. 

"  We  find  it  is  a  safe  rule,  up  to  5-in.  circumference,  to  multiply  the  square  of 
the  circumference  by  8  and  the  product  will  be  the  number  of  net  100  Ibs.  required 
to  break  the  rope. 


500 


GAS   PRODUCERS 


"  From  the  tests  we  have  from  the  U.  S.  Government  Cordage  Works,  of  the 
breaking  strength  of  tarred  Russia  and  American  hemp  cordage,  we  would  say  that 
the  above  rule  will  apply  to  tarred  cordage  as  well  as  to  manila. 

"  Where  blocks  and  falls  are  used  it  is  a  safe  rule  to  put  rope  in  use  at  one-eighth 
its  breaking  strain;  and  that  in  two  double-blocks  of  suitable  size.  Say  for  instance, 
it  is  desirable  to  raise  regularly  1000  Ibs. :  Two  double  8-in.  blocks  reeved  with  3-in. 
circumference  manila  rope  should  be  used. 

"  For  direct  pulls  on  a  single  rope,  say  up  to  5-in.  circumference,  we  find  it  safe 
where  in  constant  use  to  put  it  at  work  at  only  one-twentieth  its  breaking  strain.  For 
instance,  on  a  hoisting  machine  in  a  warehouse  where  hoists  of  1000  to  1500  Ibs.  are 
made  (the  latter  occasionally),  we  place  for  the  hook  rope  5-in.  circumference  manila 
rope.  This  gives  durability,  and  allows  for  wear  and  tear. 

"  Of  course  wear  and  tear  and  the  want  of  proper  care  must  be  allowed  for  as 
rope  grows  old.  The  best  rope  made  will  be  quickly  destroyed  by  allowing  it  to 
become  wet  and  then  putting  it  in  a  damp  cellar  or  room  where  there  is  no  circulation 
of  air." 


AVERAGE   LENGTH   PER  COIL   AND   WEIGHT   PER   100  FATHOMS 


MANILA  AND  S 

I8AL  ROPE. 

TARRED 

CORDAGE. 

Diameter  in  Inches. 

Circumference  in 
Inches. 

Length  of  Coil 
in  Feet. 

Pounds  per  100 
Fathoms-. 

Length  in 
Feet. 

Pounds  per  100 

Fathoms. 

\  or  6  thread 

1 

1300 

12 

840 

18 

A  or  9   ' 

ft 

1300 

17 

840 

29 

1  or  12   ' 

U 

1200 

•23 

840 

40 

15   ' 

1200 

31 

840 

47 

18   ' 

1100 

45 

840 

58 

21   ' 

1100 

50 

840 

68 

4 

'it; 

990 

52 

960 

64 

A 

if 

990 

70 

960 

79 

1 

2 

990 

83 

960 

94 

1 

2* 

990 

105 

960 

130 

1 

2* 

990 

125 

960 

140 

if 

2| 

990 

155 

960 

170 

l 

3 

990 

175 

960 

207 

1* 

3i 

990 

205 

960 

238 

l& 

8i 

990 

255 

960 

272 

H 

3| 

990 

280 

960 

300 

1* 

4 

960 

310 

960 

332 

if 

41 

960 

355 

960 

376 

U 

4* 

960 

410 

960 

440 

If 

4| 

960 

450 

960 

505 

itt 

5 

960 

500 

960 

573 

l! 

&i 

960 

550 

960 

610 

U 

54 

960 

610 

960 

654 

i« 

5! 

960 

690 

960 

797 

2 

6 

960 

750 

960 

900 

2A 

6J 

960 

845 

960 

1057 

2^ 

7 

960 

1000 

960 

1163 

2* 

7* 

960 

1100 

960 

1356 

2| 

8 

960 

1270 

960 

1613 

3 

9 

960 

1595 

960 

2013 

CHAPTER   XXII 


USEFUL  TABLES 


CIRCUMFERENCES  AND  AREAS  OF   CIRCLES 


Diam. 

Circum. 

Area.      Diam. 

Circum. 

Area. 

Diam. 

Circum. 

Area. 

A 

0  .  1963 

0.00307  >    8 

25.132 

50.265 

55 

172.788 

2375.83 

i 

0.3927 

0.01227     9 

28.274 

63.617  | 

56 

175.929 

2463.01 

0.5890 

0.02761     10 

31.416 

78.540 

57 

179.071 

2551.76 

i 

0.7854 

0.04909     11 

34.558 

95.033  ! 

58 

182.212 

2642.08 

0.9817 

0.07670     12 

37.699 

113.097  1 

59 

185.354 

2733.97 

| 

1.1781 

0.1104     13 

40.840 

132.732 

60 

188.496 

2827.43 

A 

1.3744 

0.1503     14 

43.982 

153.938  i 

61 

191.637 

2922.47 

i 

1.5708 

0.1963     15 

47  .  124 

176.715 

62 

194.779 

3019.07 

1.7771 

0.2485      16 

50.265 

201.062 

63 

197.920 

3117.25 

t 

1  .9635 

0.3068     17 

53.407 

226.980 

64 

201.062 

3216.99 

H 

2.1598 

0.3712 

18 

56.548 

254.469 

65 

204.204 

3318.31 

i 

2.3562 

0.4418 

19 

59.690 

283.529 

66 

207.345 

3421.19 

2.5525 

0.5185 

20 

62.832 

314.160 

67 

210.487 

3522.66 

t 

2.7489 

0.6013 

21 

65.973 

346.361 

68 

213.628 

3631.68 

if 

2.9452 

0.6903 

22 

69.115 

380  .  133 

69 

216.770 

3739.28 

i 

3.1416 

0.7854 

23 

72.256 

415.476 

70 

219.912 

3848.45 

H 

3.3379 

0.8866 

24 

75.398 

452.390 

71 

223.053 

3969  .  19 

3.5343 

0.9940 

25 

78.540 

490.875 

72 

226.195 

4071.50 

iA 

3.7306 

1  .  1075 

26 

81.681 

530.930 

73 

229.336 

4185.39 

U 

3.9270 

1.2271 

27 

84.823 

572.556 

74 

232.478 

4300.84 

1A 

4.1233 

1.3530 

28 

87.964 

615.753 

75 

235.620 

4417.86 

4.3197 

1.4848 

29 

91.106 

660.521 

76 

238.761 

4536.46 

1A 

4.5160 

1.6229 

30 

94.248 

706.860 

77 

241.903 

4656.63 

H 

4.7124 

1.7671 

31 

97.389 

754.769 

78 

245.044 

4778.36 

if 

5.1051 

2.0739 

32 

100.531 

804.249 

79 

248.186 

4901.68 

ij 

5.4978 

2.4052 

33 

103.672 

855.30 

80 

251.328 

5026.55 

1J 

5.8905 

2.7611 

34 

106.814 

907.92 

81 

254.469 

5153.00 

2 

6.2832 

3.1416 

35 

109.956 

962.11 

82 

257.611 

5281.02 

21 

6.6759 

3.54(1.") 

36 

113.097 

1017.88 

83 

260.752 

5410.61 

21 

7.0686 

3.9760 

37 

116.239 

1075.21 

84 

263.894 

5541  .77 

2| 

7.4613 

4.4302 

38 

119.380 

1134.11 

85 

267.035 

5674.51 

2$ 

7.8540 

4.9087 

39 

122.522 

1194.59 

86 

270  .  177 

5808.80 

2§ 

8.6394 

5.9395 

40 

125.664 

1256.64 

87 

273.319 

5944.68 

3 

9.4248 

7.0686 

41 

128.805 

1320.25 

88 

276.460 

6082.12 

31 

10.210 

8.2957 

42 

131.947 

1385.44 

89 

279.602 

6221.14 

3} 

10.995 

9.6211 

43 

135.088 

1452.20 

90 

282  744 

6361  .73 

3| 

11.781 

11.044 

44 

138.230 

1520.53 

91 

285.885 

6503.88 

4 

12.566 

12.566 

45 

141.372 

1590.43 

92 

289.027 

6647.61 

41 

13.351 

H  .  186 

46 

144.513 

1661  .90 

93 

292  .  168 

6792.91 

4* 

14.137 

15.904 

47 

147.655 

1734.94 

94 

295.310 

6939.78 

4| 

14.922 

17.720 

48 

150.796 

1809.56 

95 

298.452 

7088.22 

5 

15.708 

19.635 

49 

153.938 

1885.74 

96 

301.593 

7238.23 

51 

16.493 

21.647 

50 

157.080 

1963.50 

97 

304.734 

7389.81 

5* 

17.278 

23.758 

51 

160.221 

2042.82 

98 

307.876 

7542.96 

5! 

18.064 

25.967 

52 

163.363 

2123.72 

99 

311.018 

7697.69 

6 

18.849 

28.271 

53 

166.504 

2206.18 

100 

314.159 

7853.98 

7 

21.991 

38.484 

54 

169.646 

2290.22 

501 


502 


GAS   PRODUCERS 

PROPERTIES    OF    THE   CIRCLE 

Circumference  =  diameter  X  3.1416  or  3y. 
Diameter  X  .8862  =  side  of  equal  square. 
Diameter  X  .7071  =       "       inscribed  square. 
Diameter  X  .7854  =  area  of  circle. 
Length  of  arc  of  circle  =  No.  of  degrees  X  .017453 


•  •-- Cotangent 


f"~  Cosine       —  -" 

, Radius  —• — - 


FIG.  242. — Circular  Functions. 


Inches. 

1 

12 

36 

63360 


Feet. 

0.083 

1 

=  3 
=  5280 


CONVERSION   TABLES 

MEASURES  OF   DISTANCE 

Yards.  Miles. 

0.02778  =  0.0000158  = 
0.33333  =  0.0001894  = 
1  =0.000568  = 


Centimeters. 

2.539998  = 
30.47997   = 
91.43992   = 


0.39370  = 
39.37011  = 


0.03281  = 

3.28084  = 


=  1760  =1  =160934.259 

0.01094  =  0.000006   =  1 

1.09361  =  0.000621    =       100 


Meters. 
0.02539998 
0.3047997 
0.9143992 
=  1609.34259 
0.01 
1 


MEASURES   OF    SURFACE. 

Sq.  Inches.  Sq.  Feet.      Sq.  Centimeters.     Sq.  Meters. 

1          =   0.00694=         6.451589  =  0.000645 
144         =    1  =     929.03         =0.093 

0.155=   0.00108=          1  =0.0001 

1550.006  =  10.76393  =  10000  =1 

1  acre  =  4840  sq.  yards  =  43560  sq.ft.  =  a  square,  the  side  of  which  is  208.71  ft. 


Cu.  In. 
1 

1728 
231 

61.0239  = 
61023.90     =35.31476     =264.2 
1  bushel,  U.  S.  Standard  =  21 50. 42  cu.ins. 
1  bushel,  British  =2218.19  cu.ins. 

1  cu. meter  =  1000  liters 


MEASURES   OF   VOLUME 
Cu.  Feet.      R.  S.  Gallons. 
0.0005788=     0.00433  = 
1  7.4805   = 

0.1337       =      1 
0.03531      =     0.2642   = 


1  Imperial  gallon 


Liters.         Cu.  Meters. 
0.016387  =  0.000016 
=     28.31677   =0.028317 
3.78544   =0.003785 
1.  =0.001 

=  1000.  =1. 

1 . 2445  cu.ft. 
1.2837cu.ft. 
=  1,000,000  cu.cm. 


1. 20032  U.  S.  gallons  = 


277.274  cu.ins. 


USEFUL  TABLES  503- 

MEASURES   OF   WEIGHT 

Grains.  Ounces.  Pounds.  Grams.          Kilograms. 

1  =  0.00229  =  0.000143=       0.0647989  =  0.000065 

437.5         =    i.  =0.0625  28.34953     =0.02835 

7000  =16.  =1.  =  453.59243     =0.45359 

15.43236=   0.03527  =  0.002205=       1.  =0.001 

15432.35639  =  35.274     =2.20462   =1000.  =1. 

MEASURES   OF   HEAT   ENERGY 

Calorie.  B.T.U.                                    Pound  Calorie 

(1°  C.  and  1  kg.)  (1°  F.  and  1  Ib.)                         (1°  C.  and  1  Ib.) 

1.  3.968                                    2.2046 

0.252  1.                                           0.5556 

0.4536  1.8                                        1. 

Calories  per  Cu.  Meter.  B.T.U.  per  Cu.  Foot. 

1.  0.11236 

8.898  1. 

Calories  per  Kilogram.  B.T.U.  per  Pound. 

1.  1.800 

0 . 5556                 =  1 . 

TEMPERATURES 

Degrees  Fahrenheit  =  £  degrees  Centigrade +32,  or  F.°  =  1.8  C.°+32. 
Degrees  Centigrade  =  |  (degrees  Fahrenheit —32). 
•    Degrees  absolute  temperature,  T.  =C.°  +  273. 

T.  =  F.°+491. 

Absolute  zero=  —273°  on  Centigrade  scale. 
-491°  on  Fahrenheit  scale. 

Mercury  remains  liquid  to   —39°  C.,  and  thermometers  with  compressed  N  above 
the  column  of  mercury  may  be  used  for  as  high  temperatures  as  400  to  500°  C. 

HEAT   UNITS 

A  French  calorie  =1  kilogram  of  H2O  heated  1°  C.  at  or  near  4°  C. 

A  British  thermal  unit  (B.T.U.)  =  1  Ib.  of  H2O  heated  1°  F.  at  or  near  39°  F. 

A  pound-calorie  unit  =  l  Ib.  of  H20  heated  1°  C.  at  or  near  4°  C. 

1  French  calorie  =  3 . 968  B.T.U.  =2.2046  pound-calories.  ' 

1  British  thermal  unit  =  .252  French  calorie  =  .555  pound  =  calorie. 

1  pound-calorie  =  1.8  B.T.U.  =  .45  French  calorie. 

1  B.T.U.  =  778  ft.-lbs.  =  Joule's  mechanical  equivalent  of  heat. 

1  h.p.       =33,000  ft.-lbs.  per  minute 

«  8  -\  o  £4  =  42.42  B.T.U.  per  minute 
=  42.42X60  =  2545  B.T.U.  per  hour. 

The  British  Board  of  Trade  unit  is  not  a  unit  of  heat,  but  of  electrical  measurement- 
and 

=  1  killowatt  hour 

=  1000  watts  =  1T\°^-=  1.34  h.p.  per  hour. 


504  GAS   PRODUCERS 

MEASURES  OF   PRESSURE 

0    .  T~                            Inches  of  Water  Inches  of  Mercury 

Lbs.  per  Sq.m.  Kg.  per  Sq.cm.       (620)  Column>  (62°)  Column. 

1.  0.070308               27.71      =  2.0416 

14.22  1.                         394.1  29.03 

0.0361      =  0.0025                     1.          =  0.0736 

0.49         =  0.0344         =       13.98     =  1. 


TO    CHANGE    BRITISH    THERMAL    UNITS    (B.T.U.)    TO    CALORIES    OR    CALORIES    TO 

BRITISH  THERMAL   UNITS— (BATES) 

Thermal  Units.— 1°  C.=£°  F.  or  1.8°  F.;  1°  F.=£°  or  0.556°  C.;  1  kilo- 
gram =2.2046  Ibs;  1  lb  =  0.4536  kilogram;  1  calorie  =  1  kilogram  (2.2046  pounds) 
of  water  raised  through  1°  C.  (1.8°  F.)  =2.2046X1.8  =  3.968  B.T.U.,  since  1  British 
thermal  unit  is  1  pound  (0.4536  kilogram)  of  water  raised  through  1°  F.  (0.55(5°  C.), 
and  similarly  0.4536X0.556  =  0.252  calorie,  consequently 

To  convert  calories  into  British  thermal  units,  multiply  by  the  constant  3.968,  and 

To  convert  British  thermal  units  into  calories,  multiply  by  the  constant  0  252 

British  thermal  units  are  generally  given  per  cubic  foot  or  per  pound,  and  calories 
per  cubic  meter  (or  liter  =  .001  cubic  meter)  or  per  kilogram. 

1  cubic  meter  =  35.3 14  cubic  feet; 

1  cubic  foot  =0.02832  cubic  meter,  consequently 

To  convert  calories  per  cubic  meter  into  British  thermal  units  per  cubic  foot, 
multiply  the  calories  by  3.968,  giving  British  thermal  units  per  cubic  meter,  and 
divide  the  product  by  35.314,  when  the  quotient  will  be  the  number  of  British  thermal 
units  per  cubic  foot. 

To  convert  calories  per  kilogram  into  British  thermal  units  per  pound,  multiply 
the  calories  by  3.968,  giving  British  thermal  units  per  kilogram,  and  divide  the  prod- 
uct by  2.2046  when  the  quotient  will  be  the  number  of  British  thermal  units  per 
pound. 

Since  3.968-^2.2046  =  1.8  (approximately),  the  calories  per  kilogram  may  be 
multiplied  by  the  constant  1.8,  giving  the  number  of  British  thermal  units  per  pound 
directly  as  in  the  previous  case. 

To  convert  British  thermal  units  per  cubic  foot  into  calories  per  cubic  meter, 
multiply  the  British  thermal  units  by  0.252,  giving  calories  per  cubic  foot,  and  divide 
the  product  by  0.02832,  when  the  quotient  will  be  the  number  of  calories  per  cubic  meter 
directly  similarly; 

To  convert  British  thermal  units  per  pound  into  calories  per  kilogram,  multiply 
the  British  thermal  units  by  0.252,  giving  calories  per  pound,  and  divide  the  product 
by  0.4536,  when  the  quotent  will  be  the  number  of  calories  per  kilogram. 

Since  0.252^-0.4536  =  0.4536=0.556  (approximately),  the  British  thermal  units 
per  pound  may  be  multiplied  by  the  constant  0.556,  giving  the  equivalent  number 
of  calories  directly. 

Another  unit  often  employed  in  connection  with  the  quantative  measurement 
of  heat  by  scientific  writers  is  the  thermal  unit,  which  may  be  defined  as  the  quantity 
of  heat  required  to  raise  one  pound  of  pure  water  one  degree  centigrade  at  or  about  4°  C. 


USEFUL   TABLES 


505 


MEASURES  OF  ENERGY 


(I1 


Horse^power 
Hours. 


Kilowatt 
Hours. 


R  T  TT 

F.  and  1  Ib.)  Foot-pounds.         Kg.-meters. 

1  778.  107.6  =0.000393  =0.000293 

0.001285=  1.  0.1383  =  0.0000005  =0.00000083 

0.0093  7.233=  1.  =0.00000365  =  0.00000272 

2545  =1980000.        =273740.  =1.  =0.746 

=  367000.  =1.34  =1. 


3412 


=  2654200. 


1  Horsepower  =17  Ibs.  of    water  raised  from  62°  to  212°  F.  =  2.64  Ibs.  of  water 
evaporated  from  and  at  212°  F.  =0.175  Ib.  carbon  oxidized  with  perfect  efficiency. 


COMPOUND   MEASURES  OF   QUANTITY 


Grains  per  100  cu.ft. 
1 
0.437 

1000  cu.ft.  weigh,  Ibs. 

1 
62.428 


Grams  per  100  cu.m. 
2.29 
1. 

One  cu.m.  weighs,  kilograms. 
0.016 
1 


BAROMETRIC   READINGS  IN   MILLIMETERS  AND   INCHES 


Mil'meters 

Inches. 

.Millimeters. 

Inches. 

Millimeters. 

Inches. 

Millitnetere. 

Inches. 

700 

27.56 

723 

28.47 

746 

29.37 

769 

30.28 

701 

.60 

724 

.50 

747 

.41 

770 

.32 

702 

.64 

725 

.54 

748 

.45 

771 

.36 

703 

.68 

726 

.58    ' 

749 

.49 

772 

.39 

704 

.72 

727 

.63 

750 

.53 

773 

.43 

705 

.76 

728 

.66 

751 

.57 

774 

.47 

706 

.80 

729 

.70 

752 

.61 

775 

.51 

707 

.84 

730 

.74 

753 

.65 

776 

.55 

708 

.88 

731 

.78 

754 

.69 

777 

.59 

709 

.91 

732 

.82 

755 

.73 

778 

.63 

710 

.95 

733 

.86 

756 

.76 

779 

.67 

711 

.99 

734 

.90 

757 

.80 

780 

.71 

712 

28.03 

735 

.94 

758 

.84 

781 

.75 

713 

.07 

736 

.98 

759 

.88 

782 

.79 

714 

.11 

737 

29.02 

760 

.92 

783 

.83 

715 

.15 

738 

.06 

761 

.96 

784 

.87 

716 

.19 

739 

.10 

762 

30.00 

785 

.91 

717 

.23 

740 

.13 

763 

.04 

786 

.94 

718 

.27 

741 

.17 

764 

.08 

787 

.98 

719 

.31 

742 

.21 

765 

.12 

788 

31.02 

720 

.35 

743 

.25 

766 

.16 

789 

.06 

721 

.39 

744 

.29 

767 

.20 

722 

.43 

745 

.33 

768 

.24 

506 


GAS    PRODUCERS 


THERMOMETRIC  DEGREES 
CENTIGRADE  AND  FAHRENHEIT 


Degrees  C. 

Degrees  F. 

Degrees  C. 

Degrees  F. 

Degrees  C. 

Degrees  F. 

Degrees  C. 

Degrees  F. 

Degrees  C. 

Degrees  F. 

-40 

-40 

18.3 

65 

55 

131 

95 

203 

200 

392 

-34.4 

-30 

20 

68 

57.2 

135 

96.1 

205 

204.4 

400 

-30 

-22 

21.1 

70 

60 

140 

98.9 

210 

260 

500 

-28.9 

-20 

23.9 

75 

62.8 

145 

100 

212 

300 

572 

-23.3 

-10 

25 

77 

65 

149 

104.4 

220 

400 

752 

-20 

-   4 

26.7 

80 

65.6 

150 

110 

230 

500 

'    932 

-17.8 

0 

29.4 

85 

68.3 

155 

115.6 

240 

600 

1112 

-12.2 

10 

30 

86 

70 

158 

120 

248 

700 

1292 

-10 

14 

32.2 

90 

71.1 

160 

121.1 

250 

800 

1472 

-  6.7 

20 

35 

95 

73.9 

165 

126.7 

260 

900 

1652 

-   1.1 

30 

37.8 

100 

75 

167 

130 

266 

1000 

1832 

0 

32 

40 

104 

76.7 

170 

132.2 

270 

1100 

2012 

1.7 

35 

40.6 

105 

79.4 

175 

137.8 

280 

1200 

2192 

4.4 

40 

43.3 

110 

80 

176 

140 

284 

1300 

2372 

5 

41 

45 

113 

82.2 

180 

143.3 

290 

1400 

2552 

7.2 

45 

46.1 

115 

85 

185 

148.9 

300 

1500 

2732 

10 

50 

48.9 

120 

87.8 

190 

150 

302 

1600 

2912 

12.8 

55 

50 

122 

90 

194 

162.8 

325 

15 

59 

51.7 

125 

90.6 

195 

175 

347 

15.6 

60 

54.4 

130 

93.3 

200 

176.7 

350 

THE  EQUIVALENT  OF  OUNCES  PER  SQUARE  INCH  PRESSURE  IN  INCHES  OF  WATER 

AND   OF   MERCURY 


Ounces. 

Inches  of  Water. 

Inches  of  Mercury. 

Ounces. 

Inches  of  Water. 

Inches  of  Mercury. 

1 

1.7 

0.125 

9 

15.5 

1.125 

2 

3.4 

0.250 

10 

17.2 

1.250 

3 

5.2 

0.375 

11 

19.0 

1.375 

4 

6.9 

0.500 

12 

20.8 

1.500 

5 

8.6 

0.625 

13 

22.5 

1.625 

6 

10.3 

0.750 

14 

24.2 

1.75'.) 

7 

12.0 

0.875 

15 

26.0 

1.875 

8 

13.8 

1.000 

16 

27.7 

2.000 

These  conversion  tables  are  often  useful  in  natural-gas  distribution: 

HEIGHT  OF  WATER  COLUMN  IN  INCHES  CORRESPONDING  TO  VARIOUS  PRESSURES, 

IN   OUNCES   PER   SQUARE   INCH 


Pressure 
in  Ounces 
per 
Square 
Inch. 

DECIMAL  PARTS  OF  AN  OUNCE. 

0.0 

0.1 

0.2 

0.3 

0.4 

0.5 

0.6 

0.7 

0.8 

0.9 

0 

0.17 

0.35 

0.52 

0.69 

0.87 

1.04 

1.21 

1.38 

1  .56 

1 

1.73 

1.90 

2.08 

2.25 

2.42 

2.60 

2.77 

2.94 

3.11 

3.29 

2 

3.46 

3.63 

3.81 

3.98 

4.15 

4.33 

4.50 

4.67 

4.84 

5.01 

3 

5.19 

5.36 

5.54 

5.71 

5.88 

6.06 

6.23 

6.40 

6.57 

6.75 

4 

6.92 

7.09 

7.27 

7.44 

7.61 

7.79 

7.96 

8.13 

8.30 

8.48 

5 

8.65 

8.82 

9.00 

9.17 

9.34 

9.52 

9.69 

9.86 

10.03 

10.21 

6 

10.38 

10.55 

10.73 

10.90 

11.07 

11.26 

11.43 

11.60 

11.77        11.95 

7 

12.11 

12.28 

12.46 

12.63 

12.80 

12.97 

13.15 

13.32 

13.49        13.67 

8 

13.84 

14.01 

14.19 

14.36 

14.53 

14.71 

14.88 

15.05 

15.22        15.40 

9 

15.57 

15.74 

15.92 

16.09 

16.26 

16.45 

16.62 

16.79 

16.96        17.14 

USEFUL  TABLES 


507 


BEAUME  HYDROMETER  DEGREES  AND  SPECIFIC  GRAVITIES  FOR  LIQUIDS  LIGHTER 

THAN  WATER 

TEMPERATURE  60°  F.  =  15.6°  C. 


Degrees  Beaumi1. 

Specific  Gravity. 
Water  =1.000. 

Weight,  Pound 
per  Gallon. 

Degrees  Beaume'. 

Specific  Gravity, 
Water  =  1.000. 

Weight,  Pound 
per  Gallon. 

10 

1.000 

8.3328 

26 

0.901 

7.50 

11 

0.993 

8.27 

27 

0.896 

7.46 

12 

0.986 

8.22 

28 

0.890 

7.42 

13 

0.980 

8.17 

29 

0.885 

7.37 

14 

0.973 

8.11 

30 

0.880 

7.33 

15 

0.967 

8.06 

31 

0.874 

7.28 

16 

0.960 

8.00 

32 

0.869 

7.24 

17 

0.954 

7.95 

33 

0.864 

7.20 

18 

0.948 

'    7.90 

34 

0.859 

7.15 

19 

0.942 

7.85 

35 

0.854 

7.11 

20 

0.936 

7.80 

36 

0.849 

7.07 

21 

0.930 

-7.75 

37 

0.844 

7.03 

22 

0.924 

7.70 

38 

0.839 

6.99 

23 

0.918 

7.65 

39 

0.834 

6.95 

24 

0.913 

7.60 

40 

0.830 

6.91 

25 

0.907 

7.56 

BEAUME  HYDROMETER  DEGREES  AND   SPECIFIC  GRAVITIES  FOR  LIQUIDS  HEAVIER 

THAN   WATER 

TEMPERATURE  60°  F.  =  15.6°C. 


Degrees  Beaume'. 

Specific  Gravity, 
Water  =1.000. 

Weight,  Pounds 
per  Gallon. 

Degrees  Beaume". 

Specific  Gravity, 
Water  =1.000. 

Weight,  Pounds 
per  Gallon. 

0 

1.000 

8.3328 

15 

1.109 

9.24 

1 

1.007 

8.39 

16 

1.118 

9.31 

2 

1.013 

8.45 

17 

1.126 

9.38 

3 

1.020 

8.50 

18 

1.134 

9.45 

4 

1.027 

8.56 

19 

1.143 

9.52 

5 

1.034 

8.61 

20 

1.152 

9.59 

6 

1.041 

8.67 

21 

1.160 

9.67 

7 

1.048 

8.73 

22 

1.169 

9.74 

8 

1.056 

8.80 

23 

1.178 

9.82 

9 

1.063 

8.86 

24 

1.188 

9.90 

10 

1.070 

8.92 

25 

1.197 

9.97 

11 

1.078 

8.98 

30 

1.246 

10.38 

12 

1.086 

9.05 

35 

1.299 

10.82 

13 

1.094 

9.11 

40 

1.357 

11.31 

14 

1.101 

9.17 

508  GAS   PRODUCERS 

SPECIFIC  GRAVITY  AND  WEIGHT  OF  SOLID   SUBSTANCES  AT  60°  F. 


Name. 


Aluminum 2.67 

Anthracite,  solid 1 . 50 

Anthracite,  broken .... 

Asphaltum 1 . 39 

Brass 8 .40 

Brick,  common,  hard 2 .00 

Cement,  loose 1 . 25 

Charcoal .... 

Cherry,  dry 0 .67 

Clay,  dry 1 .92-2  4 

Coal,  bituminous,  solid 1 . 35 

Coal,  bituminous,  broken .... 

Coke,  loose .... 

Concrete 1 .92-2.24 

Copper 8 .85 

Earth 1 .15-1 .76 

Glass 2 .50-2 .75 

Gold : 19.26 

Granite 2 .56-2 .72 

Gravel 1 .60-1 .92 

Ice 0.92 

Iron,  cast 7 .22 

Iron,  wrought 7 .70 

Lead 11.38 

Lime,  quick,  in  bulk 0.80-0.88 

Limestone,  solid 2.72 

Limestone,  broken 2 .00 

Manganese 8 .00 

Magnesia,  carbonate 2 .40 

Mahogany 0.81 

Maple,  dry 0 .68 

Marble 2.88 

Masonry,  stone,  dry 2 . 24-2 . 56 

Masonry,  brick,  dry 1 .79 

Mercury,  32°  F 13 .62 

Mercury,  60°  F 13 .58 

Mercury,  212°  F 13 .38 

Nickel : 8 .80 

Oak 0.74-1.11 

Oxide,  purifying  sponge .... 

Pine  0.45-0.61 

Platinum 21  50 

Sand 1 .44-1 .76 

Sandstone 2 .24-2 .4 

Silver 10 . 50 

Slate 2 . 88 

Snow,  freshly  fallen 019 

Steel 7.85 

Sulphur 2  00 

Tile 1 .76-1 .92 

Tin 7.35 

Walnut,  dry 0  58 

Wax 0  98 

Zinc  .  .  7  00 


Specific  Gravity. 


Pounds  per  Cu.ft. 

166 

93 

58 

87 

52 1 

125 

78 

18 

42 

120-150 

84 

50 

30 

120-140 

552 

72-110 
156-172 

1201 

160-170 

100-120 

57.5 

450 

480 

710 

50-55 

170 

125 

499 

150 

51 

42 

180 

140-160 
112 
849.3 
846.8 
834.4 
548.7 
46-69 
30-50 
28-38 
1347 
90-110 
140-150 
655 
180 
12 

489.6 
125 

110-120 

458.3 

36 

60 

436.5 


Pounds  per  Cu.in. 


0..0963 


0.3031 


0.3195 
0.6949 


0.2604 
0.2779 
0.4106 


0.2887 


0.4915 
0.4900 
0.4828 
0.3175 


0.7758 
0.3790 
0.2834 
0.2652 


USEFUL  TABLES 


509 


SPECIFIC    GRAVITY    AND    WEIGHT    OF    GASES    AND    VAPORS    AT    32°  F.  =  0°  C.  AND 

760  MM.  =  29.92  IXS.  BAROMETER 


Name. 

Symbol. 

Specific  Gravity. 

1000  Cu.ft. 
Weigh,  Lbs. 

1  Cu.  Meter 
Weighs,  Kgs. 

Air=l. 

Hydrogen  =  1 

\ir                          

1.00 
0.0692G 
1.105 
0.970 
0.967 
1.520 
0.553 
1.037 
2.004 
0.967 
1.451 
0.898 
0.589 
2.450 
1.259 
1.177 
1.523 
1.038 
1.799 
it  0.42 
0.52 
0.62 
0.40 
0.75 
0.57 
0.85 
1.05 

14.438 
1.00 
15.96 
14.01 
13.96 
21.95 
7.98 
14.97 
28.94 
13.97 
20.95 
12.97 
8.50 
35.37 
18.18 
16.99 
21.99 
14.99 
25.99 
6.06 
7.51 
8.96 
5.78 
10.83 
8.23 
12.27 
15.16 

80.757 
5.594 
89.246 
78.322 
78.072 
122.683 
44.642 
83.691 
161.788 
78.097 
117.146 
72.510 
47.545 
197.734 
101.664 
94.984 
122.953 
83.772 
145.239 
33.92 
41.99 
50.07 
32.30 
60.57 
46.03 
70.64 
81.16 

1.2936 
0.0896 
1.4292 
1.2546 
1.2506 
1.9652 
0.7151 
1.3406 
2.5916 
1.2510 
1.8765 
1.1615 
0.7616 
3  .  1674 
1.6285 
1.5215 
1.9692 
1.3419 
2.3265 
0.543 
0.673 
0.801 
0.517 
0.970 
0.737 
1.100 
1.358 

Hydrogen  

H2 
02 
N2 
CO 
CO2 
CH< 
C2H6 
C4H,0 
C2H4 
C4H, 
C2H2 
NH3 
C12 
HC1 
H,S 
N20 
NO 
C2N2 

aboi 

<  t 

<  < 

<  c 
1  1 
it 
1  1 
1  1 

Oxvgen  

Nitrogen  

Carbon  monoxide  

Carbonic  acid  .        

Methane  (marsh  gas)  

Ethane  .        

Butane  .               

Ethylene  (olefiant  gas)  

Propylere  

\cetvlene  (ethine)  

Ammonia                   

Chlorine                   

Hydrochloric  acid  

Sulphuretted  hydrogen  .... 

Nitrous  oxide  

Nitric  oxide  

Cyanogen  

'Water  gas  blue    .         

\Vater  gas  carbureted  

Water  gas,  crude  oil  (Pacific  coast)...  . 
Oil  gas   Pintsch  

Natural  gas  

Producer  gas  

Flue  gas  

If  1000  cu.ft.  of  gas  weigh  1  lb.,  1  cu.m.  weighs  0.016  kilogram. 
If  1  cu.m.  of  gas  weighs  1  kilogram,  1000  cu.ft.  weigh  62.428  Ibs. 


SPECIFIC  GRAVITY  OF  WATER  AT   VARIOUS  TEMPERATURES 


Temperature  in  Degrees. 

Specific  Grav., 
Water  at 
4°C.=  1. 

1  Cubic  Foot 
Weighs.  Lbs. 

Temperature  in  Degrees 

Specific  Grav. 
Water  at 
4°C.=  1. 

1  Cubic  Foot 
Weighs,  Lbs. 

Celsius. 

Fahr. 

Celsius. 

Fahr 

0 

32 

0.999874 

62.42 

55 

131 

0.98579 

61.54 

4 

39.2 

1.000000 

62.42 

60 

140 

0.98331 

61.37 

10 

50 

0.999736 

62  41 

65 

149 

0.98067 

61.20 

15 

59 

0.999143 

62.37 

70 

158 

0.97790 

61.02 

20 

68 

0.998252 

62  32 

75 

167 

0.97405 

60.83 

25 

77 

0.997098 

62.26 

80 

176 

0.97191 

60.64 

30 

86 

0.995705 

62.17 

85 

185 

0.96876 

60.44 

35 

95 

0.994098 

62.08 

90 

194 

0.96550 

60  .  22 

40 

104 

0.99233 

61.97 

95 

203 

0.96212 

60.00 

45 

113 

0.99035 

61.85 

100 

212 

0.96863 

59.76 

50 

122 

0.98813 

61.70 

510 


GAS   PRODUCERS 
SPECIFIC   GRAVITY  AND  WEIGHT   OF   FLUIDS  AT   60°  F. 


Name. 


Alcohol,  pure 0 . 794 

Alcohol,  95% 0 .816 

Alcohol,  50% 0 .934 

Ammonia,  aqua,  29.01% 0 . 898 

Ammoniacal  gas  liquor  4  "ounce"  (weak) 1 .005-1 .01 

Ammoniacal  gas  liquor  60  "ounce"  (concentrated) 1.12-1.19 

Bromine 2 .97 

Carbon  disulphide 1 . 26 

Ether,  sulphuric 0 .72 

Muriatic  acid 1 . 20 

Nitric  acid 1 .217 

Oil,  linseed 0.94 

Oil,  petroleum 0 . 80 

Oil,  turpentine 0 . 87 

Sulphuric  acid 1 . 849 

Tar 1 .01-1 . 20 

Vinegar 1 .08 

Water,  pure 1 . 00 

Water,  sea 1 .03 


Specific  Gravity. 


Pounds  per  Gallon. 


6.6 
6.8 
7.8 
7.5 

8.3-8.4 

9.3-9-9 

24.7 

10.5 

6.0 

10.0 

10.2 

7.8 

6.7 


7.3 
15.4 

8.4-10.0 
9.0 
8.3 
8.6 


One  cubic  foot  of  pure  water  at  60°  F.  weighs  62.36  Ibs. 
One  gallon  of  pure  water  at  60°  weighs  8.3328  Ibs. 


COSTS   FOR    ERECTION 

Suction-gas  producer  plants: 

Anthracite  or  bituminous  coal 100  to  350  H.P.  $1.70  to  $2.50 

Lignite  fuel  ., 10  per  cent  less 

Pressure  producer  plants,  with  holder: 

Anthracite  or  bituminous  coal  or  lignite 350  H.P.  $3.00  to  $4.00 

Anthracite  or  bituminous  coal  or  lignite 350  to  1000  H.P.  $2.50  to  $3.00 

Gas  engines,  costs  for  erection  per  ton $12.00  to  $13.00 


APPENDIX 


OIL  FUEL  PRODUCER    GAS 

THE  manufacture  of  producer  gas  from  oil  may  be  divided  into  three  heads:  the 
first  is  where  the  majority  of  the  fuel  is  converted  into  CO2,  and  subsequently  reacted 
into  CO;  the  second  being  the  combustion  of  the  fuel  in  an  insufficient  atmosphere, 
the  products  of  the  combustion  being  carbonated  or  "carbureted"  in  their  passage 
through  the  vapors  of  distillation;  the  third  may  be  .called  a  distillation  process  in 
which  a  portion  of  the  oil,  usually  the  residual  (generally  including  the  asphaltum  or 
paraffin  base)  is  used  as  a  basic  fuel,  supplying  the  necessary  heat  for  distillation  or 
vaporization  of  the  volatile  matter. 

Jones  Oil-Gas  Set. — The  first  method,  consisting  of  oil-gas  sets  of  the  "Lowe 
system"  or  preferably  the  "Jones  improved"  type,  designed  by  E.  C.  Jones  of  San 
Francisco  (the  pioneer  of  oil-gas  development),  constitutes  a  most  satisfactory  ap- 
paratus. "With  this  type  of  machine  the  process  of  manufacture  becomes  more  a  mat- 
ter of  manipulation  of  the  apparatus  than  of  any  specified  change  or  adaption  of 
the  design.  In  this  instance  the  apparatus  is  operated  continuously '  instead  of  in- 
termittently. The  basic  gas  is  formed  by  the  nearly  complete  combustion  of  oil  in 
the  presence  of  steam  and  almost  enough  air  for  complete  combustion  within  'the 
generator.  The  products  are  recarbureted,  the  secondary  reaction  occurring  in  the 
checker  work  or  archers  of  the  subsequent  apparatus. 

TYPICAL    ANALYSIS    OF    OIL    PRODUCER    GAS    MANUFACTURED    IN   THE 

JONES    APPARATUS 

Component.  Per  Cent, 

C02 4 

CXH2X 2  or  less 

O2 1 

CO 10 

H2 5 

CH4 8 

N2 70 

Calorific  value 160  B.T.U.  per  cu.ft, 

By  proper  manipulation,  the  hydrogen  in  this  case  may  be  maintained  very 
low,  not  exceeding  4  or  oc/( ,  or,  under  operating  conditions,  probably  12%  as  a  low 
limit  when  using  the  more  viscous  oil,  and  hence  requiring  an  increment  of  steam. 

511 


512 


APPENDIX 


FIG.  243. — Jones  Oil-Gas  Producer  Set,  with  and  without  Checker  Brick  Filling. 


APPENDIX 


513 


The  enormous  capacity  of  these  machines,  their  sympathetic  regulation  and 
high  efficiency,  render  them  of  particular  advantage  in  the  manufacture  of  large 
quantities  of  gas  for  large  units,  say  engines  above  the  1000  H.P.  type. 

Nix-Frost  Producer. — Of  the  second  classification,  the  Xix-Frost  type  manu- 
factured by  the  Western  Gas  Engine  Company  of  Los  Angeles,  is  probably  the  most 
representative.  This  apparatus  is  extremely  similar  in  its  operation  to  the  powdered 


FIG.  244. — The  Nix-Frost  Crude-Oil  Suction  Gas  Producer. 

fuel  producer  and  may  be  said  to  be  analogous  with  the  single  substitution  of  liquid 
for  powdered  fuel.  The  data  herewith  appended  contains  some  of  the  distinctive 
features  of  the  operation  in  connection  with  the  300  H.P.  set. 

Two  or  more  Tate-Jones  burners  are  set  radially  at  about  90°. 

An  air  pressure  of  40  to  90  Ibs.  is  employed,  depending  upon  viscosity  of  the  oil. 

The  auxiliaries,  consisting  of  an  air  blower,  pump,  exhauster,  and  tar  washer,  in  an 


514 


APPENDIX 


average  plant  consume  about  10%  total  power  decreasing  with  large  size  plants  (500 
H.P.) ;  the  auxiliaries  are  estimated  to  consume  about  35  H.P. 

The  capacity  of  the  15  ft.  X5  ft.  generator,  with  net  diameter  of  3  ft.  reduced  at 
the  arch  to  18  ins.,  is  rated  at  300  H.P. 

With  an  exhauster  a  suction  of  approximately  8  ins.  of  water  is  constantly  main- 
tained upon  the  generator.  This  is  supposed  to  prevent  or  minimize  the  formation 
of  coke  and  lampblack. 

The  economy  guaranteed  is  1  b.h.p.h.  per  1|  pounds  of  oil  (18,500  B.T.U. 
per  Ib.) . 

The  following  tests  of  the  oil-producer  gas  made  in  the  Nix-Frost  system  are 
by  Prof.  William  F.  Durant  of  Leland-Stanford  University. 

TEST   OF  ENGINE   AND   QUALITY   OF   OIL 


Time. 

Elapsed  Time, 
Minutes. 

R.p.m. 

Brake  H.P. 

Rate  of  Oil  per 
Hour. 

H.P.  Hours. 

Actual  Oil. 

1:15 

2:00 

45 

197.33 

111.3 

105.3 

83.48 

79 

3:00 

60 

192.70 

108.7 

108.0 

108.70 

108 

4:00 

60 

195.00 

110.0 

109.0 

110.00 

109 

4:00 

5:30 

30 

195.50 

110.3 

106.0 

55.  15 

53 

6:00 

60 

193.60 

109.2 

109.0 

109.20 

109 

7:00 

60 

198.70 

112.1 

109.0 

112.10 

109 

7:35 

8:35 

60 

196.40 

110.8 

107.5 

110.80 

107.5 

9:35 

60 

•*183.10 

103.3 

112.5 

103.30 

112.5 

10:20 

45 

*186.30 

105.2 

110.7 

78.90 

75.5 

Totals                    

871.63 
108.95 

862.5 
107.81 
0.99  Ib. 

646.5 
107.75 
0.9771b. 
19°  Be. 

Average  for  8  ] 
Oil  per  horse-p 
Omitting  the  k 
Totals 
Average 
Oil  per  1 
Gravity 

lours                                                   

ower  hour  »  

ist  two  hours,  the  results  are: 

661.83 
110.31 

for  six  hours 
lorse-power  he 
of  oil 

>ur    .          .        

*  One  sparker  on  engine  was  occasionally  missing  fire. 


ANALYSES   AND   CALCULATED   HEATING   VALUE   OF   GAS 


Time. 

12:  20  P.M. 

2:00  P.M. 

4:00  P.M. 

6:00  P.M. 

8:00  P.M. 

Average. 

Carbon  dioxide  CO2 

3.8 

3.8 

3.7 

3.6 

4.1 

3.80 

Oxvcrpn                           .  .  O? 

3.6 

3.7 

4.3 

3.7 

3.4 

3.74 

Illuminants  C«,ti2n 

4.6 

3.0 

2.6 

4.5 

2.5 

3.44 

Carbon  monoxide  CO 
Hydrogen  H2 

11.0 
3.8 

11.5 
5.4 

10.8 
7.0 

11.4 
5.0 

11.7 
6.60 

11.28 
5.56 

Methane        CH4 

6.9 

6.0 

4.8 

6.0 

6.0 

5.94 

Nitrogen  N2 

66.3 

66.6 

66.8 

65.8 

65.7 

66.24 

Calculated  B  T  U  

*202.0 

173.0 

156.7 

196.4 

169.5 

179.53 

*  Before  starting  engine. 


APPENDIX  515 

The  Amet-Ensign  Producer. — The  last  classification  is  typified  in  the  Amet- 
Ensign  apparatus,  manufactured  by  the  Western  American  Gas  Engine  Company 
of  Phoenix,  Arizona.  This  apparatus  is  exceedingly  compact.  The  100  H.P.  ma- 
chines occupy  a  floor  space  of  only  2  ftX3  ft.  It  consists  of  a  small  rectangular  brick- 


FIG.  245. — Amet-Ensign  Oil-Gas  Producer. 

lined  retort  about  30  in.  square  X  4  ft  long  with  7  in.  fire-brick  linings.  This  retort  is 
equipped  with  an  apron  or  shelf  pointing  downward  at  an  angle  of  about  45°  from 
the  wall  and  extending  about  a  foot  in  length  into  the  interior  of  the  chamber. 

Over  this  apron  or  shelf  the  total  oil  supply  of  the  producer  is  dripped.     The 


516 


APPENDIX 


volatile  portion  of  the  oil  being  evaporated  during  its  passage  over  this  hot  plate, 
and  the  residuals,  usually  consisting  of  tar,  asphalt,  or  paraffin,  dropping  from  the 
edge  encounter  an  air  blast  entering  the  bottom  of  the  retort  where  they  are  con- 
sumed, the  result  of  this  combustion  supplying  the  heat  for  vaporizing  the  oil  in  its 


FIG.  246. — Battery  of  Amet-Ensign  Producer. 

passage  over  the  apron.     The  products  of  this  combustion  are  presumed  to  be  recar- 
bureted  when  combined  with  the  oily  vapors  resulting  from  the  earlier  distillation. 
The  attached  data  indicates  some  of  the  operating  conditions  of  the  Amet-Ensign 
retort  of  the  100  H.P.  size. 


APPENDIX 


517 


This  oil  producer  has  the  following  peculiarities: 

The  economy  is  9  b.h.p.h.  per  gallon  of  oil.  In  commercial  service  they  guar- 
antee 7  h.p.  per  gallon  oil  (18,500  B.T.U.  per  lb.). 

The  thermal  efficiency  claimed  by  the  maker  is  58  to  62%. 

As  to  the  nature  of  the  gas,  a  wide  range  is  possible  by  the  method  of  operation, 
varying  from  101  to  210  B.T.U.  per  cu.ft,;  maximum  hydrogen,  3%;  180  B.T.U. 
guaranteed  by  makers,  also  450  cu.ft.  per  1  gallon  of  oil. 

The  auxiliaries  are  the  oil  pump  and  blower,  the  percentage  of  total  power  used 
by  auxiliaries  being  2.5%.  A  centrifugal  gas  washer  has  also  been  used  to  advant- 
age, consuming  probably  2.5  to  5%  additional. 


A  =  Recort. 

B  =  Apron  or  distillation  plate. 

C  =  Oil  reservoir. 

D  =  Air  blast 

E  =  Take-off  or  stack. 

F  =  Combustion  area  (where  oil  residue  is  burned  by  air 

blast.) 
G  =  Distillation  area  (where  volatile  is  distilled  on  apron 

or  plate.) 


FIG.  247. — Section  of  Amet-Ensign  Producer,  showing  Oil-vaporizing  Plate. 

The  maximum  air  blast  is  19  in.  of  water  to  6  oz.;  sufficient  air  pressure  is  main- 
tained upon  the  oil  to  balance  the  pressure  of  the  blast  and  compensate  for  any  inter- 
nal pressure  of  the  retort. 

Shut-downs  or  intermission  of  6  to  8  or  24  hours  (depending  upon  nature  of  load , 
oil,  or  load  factor)  are  required;  to  withdraw  coke  requires  5  to  15  minutes. 

Every  20  to  30  minutes  it  is  necessary  to  burn  out  stack  of  soot  and  lampblack; 
this  requires  H  to  2^  minutes. 

A  tank  or  gasholder  for  100  H.P.  at  the  U.  S.  Reservation  service  plant  has  a 
capacity  of  2500  cu.ft. 

The  fuel  is  crude  oil,  Bakersville  district,  of  which  1  gal.  weighs  7.7  Ibs.;  this  oil 
has  18,500  B.T.U.  per  lb.  oil,  and  42  gals,  equal  1  bbl. 

TYPICAL    ANALYSIS    OF    GAS    MADE    IN    THE    AMET-ENSIGN    OIL    GAS    PRODUCER 

B.T.U.  per  cu.ft 171 . 85 

Claimed  thermal  efficiency 39  to  63% 

Operating  ditto 55% 


CO2  

4.5 

CO  

7.4 

02  

0.4 

CH4  

12. 

H  

3.1 

N2  

71.9 

100.0 


518  APPENDIX 

Gasifying  Oil. — There  can  be  little  question  but  that  the  most  efficient  method 
of  gasifying  oil  is  that  which  breaks  up  the  oil  in  sequence  of  fractional  distillations, 
the  process  being  very  similar  to  that  used  in  the  refining  of  oil.  Such  an  arrange- 
ment should  distil  the  lighter  hydrocarbons  and  illuminants  at  a  relatively  low  tem- 
perature without  "crocking,"  cracking,  or  over-cooking,  and  prevents  the  dissocia- 
tion of  these  lighter  hydrocarbons  into  lampblack  or  coke. 

The  heat  in  such  process  being  gradually  increased  throughout  the  progress  of 
the  process,  each  fraction  should  be  vaporized  at  its  critical  temperature;  that  is  to 
say,  the  heat  most  appropriate  to  that  particular  fraction,  the  ascending  temper- 
ature being  progressively  maintained  until  the  volatile  matter  is  completely  driven  off 
and  the  residue  brought  to  the  point  of  volatilization.  Such  an  arrangement  pre- 
vents a  waste  from  either  extreme  quantities  of  tar  or  lampblack  and  seems  to  be 
the  natural  order  of  the  process. 

It  should  be  borne  in  mind  that  the  oil  or  oily  vapor  should  be  brought  into 
direct  contact  with  any  iron  or  other  metal  substance  as  little  as  possible.  This  may 
be,  for  a  number  of  reasons,  probably,  because  of  the  coefficient  of  heat  transference 
of  metals  as  compared  with,  say,  fire-brick,  and  also  possibly  because  of  their  reflecting 
or  refracting  qualities.  At  any  rate  it  would  appear  that  the  metal  seems  to  con- 
centrate the  heat  upon  the  oil  globule  or  monecule  with  the  result  of  vaporizing  the 
hydrogen  content  too  rapidly  and  leaving  the  carbon  residue  precipitated  in  solid  or 
semi-solid  form.  This  is  known  as  "frying  the  oil,"  and  is  the  cause  of  many  serious 
difficulties  in  operation,  principally  through  stoppage  and  waste  in  the  form  of  tarry 
compounds,  lampblack,  coke  or  naphthaline. 

Oil. — The  oil  produced  in  the  United  States,  while  practically  all  composed  of 
about  85%  of  carbon  and  15%  hydrogen,  may  be  classified  under  two  distinct  heads, 
namely:  those  possessing  a  paraffin  base,  which  geographically  include  the  principal 
oils  of  Texas,  Oklahoma  and  the  Southern  States,  and  those  possessing  an  asphalt 
base,  which  are  limited  in  the  main  to  California.  Although  similar  in  their  ultimaate 
analysis,  the  combinations  of  sulphur  and  carbon  appear  in  various  groups  and  in  a 
large  diversity  of  compounds.  Oils  in  even  adjacent  wells  will  show  marked  differ- 
ences in  these  analyses  as  well  as  in  the  extraneous  matter  which  they  may  entrain, 
or  their  sulphur  content. 

The  followinn  typical  analysis  will  sufficiently  illustrate  samples  collected  from 
various  localities: 


DISTILLATION   TESTS   OF   VARIOUS   OILS 

(Specific  gravity  of  oil  at  60°  F.,  31.50°  Be.  Fractions  10%  by  volume.) 

KANSAS  OIL.  INDIANA  OIL. 

First  fraction 95°  C.  to  200°  C.  60°  C.  to  175°  C. 

Second  fraction 200°  C.  to  285°  C.  175°  C.  to  256°  C. 

Third  fraction 285°  C.  to  320°  C.  256°  C.  to  294°  C. 

Fourth  fraction 320°  C.  to  330°  C.  294°  C.  to  315°  C. 

Fifth  fraction 330°  C.  to  345°  C.  315°  C.  to  330°  C. 

Sixth  fraction 345°  C.  to  360°  C.  330°  C.  to  337°  C. 

Seventh  fraction 337°  C.  to  340°  C. 

Eighth  fraction 340°  C.  to  360°  C. 

Coke  (per  cent  by  weight) 77%  1 . 00% 


APPENDIX 


519 


The  tenth  fraction  of  the  Kansas  oil  is  thick  and  on  cooling  turns  to  a  vaseline- 
like  mass. 

BEAUMONT,   TEXAS,    OIL 
(Color,  dark  red;    specific  gravity,  0.9336  or  20°  Be.;    water,  trace.) 


Frac- 
tion. 

Tempera- 
ture of 
Distance, 
Deg.  F. 

Per  Cent 
by 

Volume. 

Per  Cent 
by 
^  eight. 

Specific  Gravity 
Direct  Baume. 

Color  of  Fraction. 

Resume. 

Sp.  Gr. 

Deg.  B. 

1 
2 

3 
4 
5 
6 
7 
8 
9 
10 
11 
12 
Coke 

Total 

200° 
200-250°  { 

250-300° 
300-350° 
350-400° 
400-450° 
450-500° 
500-550° 
550-600° 
600-650° 
650-700° 
700-730° 

Water  oil 
Water  oil 
0.6 
0.9 
0.5 
2.6 
5.7  , 
7.9 
12.9 
20.2 
33.4 
8.8 
4.0 

Water  oil 
|  Water  oil 
1.79 

2.37 
5.30 
7.45 
12.32 
19.55 
32.44 
8.79 
4.06 

Water  212°  F.,  trace. 
Napthas,  200-302°  F. 

15% 

Burning  oil  302-572°  F., 
39.7% 

Paraffin     oils     572     to 
730°  F.,  56.3% 
By  weight  4.02% 

0.8385 

0.8533 
0.8681 
0.8803 
0.8912 
0.9039 
0.9067 
0.9325 
0.9473 

37.0 

34.1 
31.1 
29.0 
27.1 
24.9 
24.4 
21.0 
17.8 

Apple  green.  .  . 
Canary  

Chrome  yellow 
Spruce  

Terra-cotta.  .  . 
Bronze  green  .  . 
Dk.  bronze  gr'n 



97.5 

98.09 



CALIFORNIA  OILS 
OIL  USED  BY  Los  ANGELES  GAS  AND  ELECTRIC  Co. 

FROM   W^HITTIER-FULLERTON    WELLS    OP    THE     UNION   OlL    Co. 

Gravity  at  60°  F 20°  Be. 

Calorific  value 18,500  B.T.U.  per  Ib. 

Sulphur 0.85% 

Water None  to  1% 

Flash  point  (open  cup) 100°  F. 

DISTILLATION  PRODUCTS. 

Up  to  350°  F '....  6%  of  45°  Be.  distillate 

From  350  to  500°  F 24%   of  35° 

From  500  to  650°  F 20%   of  26°       " 

From  650  to  asphalt 30%  of  22°        " 

From  asphalt  "  D" 20% 

The  California  oils,  are  usually  heavy  in  gravity,  some  in  commercial  service 
running  as  low  as  11°  Be.  These  of  course  require  pre-heating  prior  to  admission  to  a 
burner. 


GLOSSARY 


Absolute    Temperature. — The  temperature  of  a   substance  reckoned  from  that  temperature 

—401°  below  the  zero  on  the  Fahrenheit  scale  and  273°  below  the  zero  on  the  centigrade 

scale — at  which  all  heat  is  supposedly  absent. 
Avogadro's  Law. — The  temperature  and  pressure  being  the  same,  the  number  of  molecules  in 

a  unit  volume  of  all  true  gases  is  the  same  for  all  gases.     Therefore  every  gas  molecule 

occupies  the  same  space. 
Baffle. — A  term  applied  to  partitions  designed  to  change  the  course  of  moving  gases    in  the 

combustion  chamber  or  among  the  boiler  tubes. 
Base  Values. — A  term  used  to  designate  the  abscissa  value  of  any  point  on  a  curve — that  is,  the 

horizontal  distance  of  that  point  from  the  left  side  of  the  chart. 

Black  Body  — A  term  used  to  designate  a  hollow  body  whose  walls  are  all  at  the  same  temper- 
ature.    If  an  extremely  small  hole  were  made  in  such  a  body,  heat  would  be  radiated  through 

the  hole  in  proportion  to  the  difference  of  the  fourth  powers  of  the  absolute  temperatures 

ot  the  black  body  and  the  surrounding  objects. 
British  Thermal  Unit. — That  quantity  of  heat  which  is  required  to  raise  the  temperature  of 

1  11).  of  pure  water  through  1°  F.  at  or  near  39.1°  F.,  the  temperature  of  maximum  density 

of  water.    The  abbreviation  B.T.U.  is  used  in  this  volume. 
Caking  Coal. — A  term  applied  to  coal  which  fuses  together  when  burning — a  coal  that  is  not 

free  burning. 
Carbon. — Available  hydrogen  ratio.     The  total  carbon  content  of  coal  divided  by  the  available 

hydrogen. 
Catalyzer. — A   substance   whose   presence,   among  the   substances  participating  in  a  chemical 

reaction,  hastens  or  retards  the  speed  of  the  reaction,  although  the  nature  and  total  amount 

of  catalyzer  present   is  always  the  same  at   the  end  as  at   the  beginning  of  the  reaction,  so 

far  as  can  be  detected. 
Cellulose. — A   substance   represented   chemically   by   the   expression   C6H10O5.      It  is  the   basis 

of  wood  structure,  excluding  a  slight  amount  of  mineral  ash  in  the  cell  walls. 
Clinker. — A  term   used   herein  to  designate  the  more  or  less  molten  or  fusible  portions  of  ash 

(including  some  carbon)  drawn  from  the  grate  and  ash  pit. 
CO. — Abbreviation  for  carbon  monoxide. 
CO2. — Abbreviation  for  carbon  dioxide. 
Combustible. — -A  loose  expression  and  misnomer  for  the  phrase  "  coal  free  from  moisture  and 

ash."  sometimes  called  "  pure  coal.''     The  pounds  of  "  combustible  "  used  in  every  steam 

test  have  been  computed  in  two  \vays,  as  follows: 

1.  Obtained  by  subtracting  from  the  total  Mounds  of  dry  coal  fired  the  pounds  of  ash 

and  combustible  drawn  out  of  the  ash  pit  and  through  the  fire  doors  in  cleaning  the  tire. 

521 


522  GLOSSARY 

2.  The  weight  of  the  coal  fired  is  corrected  for  moisture  and  ash  as  given  by  the 
proximate  analysis,  thereby  giving  the  pounds  of  "  combustible  "  fired.  From  this  amount 
is  subtracted  the  pounds  of  "  combustible  "  lost  in  the  refuse,  giving  the  total  pounds  of 
"  combustible  "  actually  ascending  from  the  grate  during  the  test. 

Combustible  Zone. — In  this  zone  the  air  and  steam  meet  the  carbon,  the  oxygen  uniting  with 
the  incandescent  C  to  form  CO2,  while  the  steam  is  superheated  and  possibly  begins  to 
decompose. 

Conduction. — The  process  of  transferring  heat  by  direct  contact — as  when  heat  travels  along 
a  rod,  or  from  a  hot  stove  lid  to  a  flat  iron  resting  on  it. 

Convection. —  The  addition  to,  or  removal  from,  a  body  of  heat,  by  gases  or  liquids  circulating 
in  direct  contact  with  the  body;  as  the  removal  of  heat  from  a  .steam  radiator  by  the 
circulation  of  air. 

Decomposition  Zone. — This  is  where  CO  is  generated,  the  steam  decomposed  into  H,  and  the 
CO 2  reduced  to  CO.  A  large  amount  of  heat  will  be  absorbed  in  this  zone  to  compensate 
for  the  carbonization  of  CO2  and  the  decomposition  of  the  steam.  In  order  that  the  reactions 
may  take  place,  the  temperature  must  be  kept  above  1800°  F. 

Distillation,  Destructive. — Destructive  distillation  is  the  process  of  heating  a  substance  beyond 
the  point  of  decomposition  Avithout  the  access  of  air.  The  object  may  be  the  dry  residue, 
the  condensed  distillate,  or  the  gases  evolved.  The  residue  will  always  be  carbon. 

Distillation,  Fractional. — This  is  the  separating  of  different  constituents  from  a  composite 
substance.  It  is  made  possible  by  the  fact  that  different  substances  pass  into  vapors  at 
different  temperatures. 

Distillation  Zone. — This  occupies  the  upper  part  of  the  fire.  The  addition  of  fresh  fuel  always 
lowers  the  temperature,  but  the  heat  from  the  lower  zones  distils  the  volatile  constituents 
of  the  fresh  fuel.  The  nature  of  the  hydrocarbons  will  depend  upon  the  temperature.  If 
the  temperature  is  kept  high,  the  hydrocarbons  will  be  easily  broken  up,  and  the  hydro- 
gen liberated.  This  means  a  large  yield  of  permanent  gases  and  very  little  tar  or  soot. 
If  the  temperature  is  kept  low,  the  hydrocarbons  will  be  easily  condensed  and  the 
amount  of  tar  and  soot  will  be  greatly  increased.  For  the  complete  distillation  of  the 
coal,  a  long  exposure  to  a  high  temperature  is  necessary  on  account  of  its  tendency  to  coke 
into  large  masses  which  are  broken  up  with  difficulty. 

Dissociation. — The  state  of  separation  of  the  molecules  of  a  substance  into  two  or  more  parts. 
A  term  used  herein  to  denote  effects  due  to  high  temperatures. 

Dry  Chimney  Gases. — In  all  calculations  in  this  glossary  this  term  includes  CO2,  02,  CO,  and 
N2  gases. 

Furnace  Efficiency,  or  per  cent  of  completeness  of  combustion,  denoted  by  E3,  is  the  ratio  of 
the  heat  actually  evolved  in  the  furnace  to  the  potential  heat  of  the  combustible  ascending 
from  the  grate. 

Empirical  Formula. — A  formula  expressing  the  actual  relations  between  two  or  more  variables 
and  constants,  but  not  founded  on  known  laws.  Cf.  "  Rational  formula." 

Endothermic. — An  adjective  describing  a  chemical  reaction  which  can  take  place  only  by 
absorbing  heat  from  the  surroundings  or  by  reducing  the  temperature  of  the  reacting  matter. 
The  opposite  of  exothermic. 

Exothermic. — An  adjective  describing  a  chemical  reaction  which  evolves  heat.  The  opposite 
of  endotheric. 

Firing,  Direct. — By  direct  firing  is  meant  burning  coal  or  other  solid  fuel  in  a  fire-box  close  to 
the  working  chamber  and  in  a  layer  so  thin  that  enough  free  atmospheric  oxygen  passes 
through  some  of  the  wider  crevices  between  the  lumps  of  fuel,  both  to  burn  the  carbonic 
oxide  generated,  by  the  incomplete  combustion  of  the  fuel,  by  the  limited  quantity  of  air 
which  passes  through  other  and  narrower  crevices,  and  also  to  burn  the  hydrocarbons,  if 


GLOSSARY  523 

any,  distilled  from  the  fuel.  Thus  both  the  combustible  gas  and  the  air  for  burning  it  escape 
simultaneously  and  side  by  side  from  the  surface  of  the  fuel,  the  flame  beginning  at  the  very 
surface  of  the  fuel. 

Firing,  Gas. — By  gas-firing  is  meant  chiefly  burning  the  fuel  in  a  layer  so  thick  that  all  of  the 
oxygen  of  the  air  which  passes  through  it  combines  with  the  fuel,  and  that  nearly  all  of  it 
forms  carbonic  oxide  with  the  carbon  of  the  fuel;  so  that  from  the  surface  of  the  fuel 
escapes  a  stream  of  combustible  gas,  chiefly  the  carbonic  oxide  thus  formed,  and  hydro- 
carbons from  the  distillation  of  the  fuel,  diluted  with  atmospheric  nitrogen.  The  stream 
of  gas  is  in  turn  burnt  by  air  specially  admitted  for  this  purpose.  In  short,  in  direct-firing 
the  fuel  bed  is  so  thin  that  it  delivers  flame  direct  from  its  surface;  in  gas-firing  it  is  so 
thick  that  it  delivers  there  a  stream  simply  of  c  mbustible  gas.  This  is  the  essential 
distinction. 

Fixed  Carbon. — A  term  applied  to  that  portion  of  the  carbon  in  a  coal  left  after  the  "volatili- 
zation" process  of  the  proximate  analysis.  It  is  obtained  by  subtracting  from  100  the  per- 
centages of  ash,  moisture,  and  volatile  matter. 

Free-Burning  Coal. — A  term  applied  to  coal  which  when  thrown  in  the  fire  burns  without  the 
separate  pieces  of  coal  fusing  together.  A  non-caking  coal. 

"Free"  Moisture. — Moisture  which  is  driven  off  from  coal  when  subjected  to  a  tempertaure  of 
105°  C.  (221°  F.)  for  one  hour. 

Gram  Molecule. — An  amount  of  a  substance  in  grams,  numerically  equal  to  the  molecular 
weight  of  the  substance.  For  instance,  a  gram  molecule  of  water  is  18  grams,  the  molecular 
weight  of  water  being  18  (2  of  hydrogen  and  16  of  oxygen). 

Hydrocarbon  Gases  (Hydrocarbons). — Gases  which  are  distilled  from  coal  when  it  is  heated. 
They  are  high  in  heating  value,  approximately  1J  times  as  high  in  B.T.U.  per  Ib.  as  pure 
carbon.  They  usually  occur  in  three  forms,  expressed  by  the  formulas:  CnHn,  CnHzn,  and 

Cntl  2/1+2- 

Ignition  Temperature. — The  ignition  temperature  of  a  substance  is  that  temperature  to  which 

it  must  be  raised  in  the  presence  of  oxygen  to  cause  the  two  to  unite  by  combustion.     This 

temperature  is  rather  indefinite,  as  extremely  slow  union  begins  far  below  the  point  of  rapid 

union.     For  any  one  substance  there  are  generally  two  temperatures,  within  perhaps  200° 

F.  of  each  other,  at  the  lower  of  which  the  rate  of  combustion  is  inappreciable  and  at  the 

higher  of  which  it  is  almost  infinite. 
Kinetic  Theory  of  Gases. — This  theory  postulates  that  gases  consist  of  immense  numbers  of 

individual  molecules  moving  among  each  other  with  enormous  velocities.     The  sum  of  the 

molecular  impacts  against  the  sides  of  a  containing  vessel  constitutes  the  pressure  of  a  gas. 

Raising  the  temperature  of  a  gas  inceases  the  molecular  speed,  and  consequently  the  force 

of  impact. 
Mass  Action,  Law  of. — The  speed  of  a  chemical  reaction  is  proportional  to  the  product  of  the 

weights  of  reacting  substances  present,  in  unit  volume,  the  weight  of  each  substance  being 

expressed  in  gram-molecules. 

(>2. — Abbreviation  for  oxygen  (one  gaseous  molecule  made  up  of  2  atoms  of  O). 
Orsat  Apparatus. — An  instrument  for  determining  the  percentages  of  carbon  dioxide,  oxygen, 

and  carbon  monoxide  by  absorbing  them  successively  in  certain  solutions.     (See  text-books 

on  gas  analysis). 

Potential  Heat. — A  term  applied  to  the  heat  in  coal  as  determined  by  a  calorimeter. 
Probability  Curve. — The   graphic   plotting   of    certain   mathematical  equations  expressing  the 

likelihood  of  a  quantity  being  more  or  less  different  from  what  it  "  ought  "  to  be. 
Proximate  Analysis  of  Coal. — An  empirical  method  of  determining  the  percentage  of  "  free  " 

moisture,  of  "volatile  matter,"  of  "fixed  carbon"  and  of  ash  in  coal.     The  method  of 

determination  varies  somewhat  with  different  chemists. 


524  GLOSSARY 

Pyrometer. — An  instrument  for  measuring  high  temperatures. 

Radiation. — The  process  of  transferring  heat  through  space  from  one  body  to  another  without 
the  aid  of  tangible  substance;  for  example,  the  transfer  of  heat  from  the  sun  to  the  earth. 

Rational  Formula. — A  formula  deduced  from  fundamental  laws,  as  of  physics. 

Refuse. — Clinker,  ash,  and  unconsumed  coal  taken  from  the  ash  pit  and.  pulled  out  of  the 
furnace  when  cleaning  fire. 

Seger  Cones. — Small  pyramids  made  of  various  chemicals  variously  mixed.  The  temperatures 
of  softening  of  the  different  cones  are  fairly  well  known.  Several  of  them  are  put  into  a 
furnace  in  a  row,  each  having  a  melting  point  intermediate  between  its  neighbors.  By 
watching  the  curling  over  of  the  tips  one  can  form  a  fairly  correct  estimate  of  the  average 
temperature. 

Stefan  and  Boltzmann's  Law. — The  amount  of  energy  radiated  by  a  black-body  surface  to 
another  body  is  proportional  to  the  difference  of  the  fourth  powers  of  their  absolute 
temperatures. 

Straight-line  Function. — A  value  changing  directly  or  inversely  with  a  variable,  so  that  if 
simultaneous  values  are  plotted  on  co-ordinate  paper,  the  points  would  lie  in  a  straight  line. 

Temperature  Gradient. — Any  continuous  change  of  temperature  in  a  body  actively  conducting 
heat. 

Ultimate  Analysis  of  Coal. — A  chemical  analysis  so  made  as  to  give,  in  percentages,  the 
amounts  of  carbon,  hydrogen,  oxygen,  nitrogen,  and  ash  in  a  dry  coal.  The  sulphur  is 
separately  determined. 

Unaccounted-for  Loss. — That  percentage  of  the  potential  heat  of  a  combustible  which  remains 
after  deducting  all  the  known  expenditures  of  heat. 

Velocity. — A  term  loosely  applied  to  the  speed  of  a  chemical  reaction,  for  example,  combustion. 
It  is  proportional  at  any  instant  to  the  rate  of  formation  of  new  substance  by  the  reaction. 

Volatile  Matter  from  Proximate  Analysis. — Or  volatile  combustible  matter,  "as  it  is  often  in- 
correctly termed,  is  the  mixture  of  gases,  together  with  some  particles  of  carbon,  driven  off 
when  a  sample  of  finely  ground  coal  is  heated  in  a  closed  vessel.  This  is  an  arbitrary  deter- 
mination, dependent  on  the  operator,  and  the  conditions  under  which  it  is  made.  A  committee 
from  the  American  Chemical  Society  has  suggested  a  method  of  volatilization  which  is 
generally  followed.  This  method  gives  fairly  concordant  results  when  the  same  operator, 
using  the  same  apparatus,  makes  duplicate  determinations  on  the  same  sample  of  coal. 

Volatile  Carbon. — A  name  given  to  that  part  of  the  carbon  in  coal  which  is  expelled  in  the 
process  of  volatilization  by  the  "  standard  method  "  of  proximate  analysis.  It  exists  in 
the  "  volatile  matter  "  resulting  from  distillation,  largely  in  combination  with  hydrogen 
as  gaseous  hydrocarbons. 

Water  of  Composition. — A  fictitious  value  determined  by  uniting  the  total  oxygen  in  dry  coal 
with  such  a  part  of  the  hydrogen  as  would  be  required  to  form  water. 


INDEX. 


Absolute  temperatures  and  pressures  of 

gases 199 

Absorption  of  heat  by  air 420 

Accidents  and  their  prevention 86,  91 

Acetylene,  properties  of 195,  219 

Adiabatic   expansion  and  compression  of 

gases 197 

Air,  combustion  requirements 374 

composition  of 200 

condensing  moisture  in 391,  393 

data  on  moving 153,  155 

heat  absorption  by 420 

impurities  in 482 

pre-heating  of 344 

properties  of 195,  220 

required  to  burn  gases 209 

supply  for  combustion 376 

Air  excess,  effect  on  combustion, 

310,  375,  376,  377 

effect  on  temperature 367,  368 

Alloys  for  testing  temperature 403,  404 

Altitude,  influence  upon  horse-power  of  gas 

engines 285 

Amet-Ensign  crude  oil  gas  producer 515 

Ammonia  in  gas,  test  for 249 

Analyses,  ash  in  coals 169 

ash  from  producers 130 

blast-furnace  gas 308 

burning  gas 371 

cement 336 

commercial  gases 221-233 

coal,  calculating  heat  value  from 169 

coal,  sampling  for 175 

crude  oil  gas 511,  514,  517 

fire-brick  joints 485 

gas  coals 167 

lignites 129 

natural  gas 219 

vegetable  fuels 162 

Analyses  of  producer  fuels : 

anthracite  coal 183 

by-product  coke 187 


Analysis  of  producer  fuels : 

charcoal 189 

gas-house  coke 186 

lignite 129,  183,  184,  185 

peat 189 

Pennsylvania  gas  coal 1 82 

Peruvian  coal 184 

semi-anthracite 183 

tan  bark 186 

wood 182,  189 

Analyses  of  producer  gases : 

anthracite  fuel 224,  225 

bituminous  fuel 225 

Loomis-Pettibone 223 

mixed  gas 223 

power  gas 231 

Siemens  gas 225 

suction  producer 224 

Washburn  and  Moen 223 

Wood,  R.  D.,  Co 229 

Analysis  apparatus,  gas: 

carbon  dioxide  test 249 

checking  results 248 

Morehead  burette 242 

Orsat  apparatus 238 

Orsat,  U.  G.  I.  form 241 

sampling .- 104,  245 

Analysis,  carbon  dioxide  apparatus: 

general  tests 249 

Sarco  recorder 254 

Tait  burette 249 

Uehling  composimeter 251 

Wise  indicator 257 

Analysis,  coal,  crucible  test 168 

dust  in  furnace  gas 55 

tar,  in  gas,  securing  of  samples 73 

Angle-of-repose  grate 43 

Anemometer    for    measuring    velocity    of 

gases 148 

Anthracite,  coal 163,  164 

gas,  Smith  suction  producer 182,  183 

producer  gas 224,  227,  228 

525 


526 


INDEX 


I'ACIE 

Anti-pulsations  for  gas  engine  supply-pipe.  2<S1 

Aqueous  vapor,  in  air 201 ,  204 

in  engine  gas 2(53 

tension  of 200 

Area  of  circles 501 

orifices  of  given  dimensions I  •">'.) 

producer  Hues 24 

Ash,  analyses  of  in  coals Hi'.) 

and  clinker  in  producer 7 

from  powdered  fuel 134 

from  producers 130 

powdered  fuel  producers 135) 

fusing  of  in  producer 16 

losses  due  to  carbon  in 6 

Asphyxiation  by  gas 91 

Aspirator  for  sampling  gas 248 

Atomic  weights 214 

Back-firing 106 

Baffling  separators,  dust 64 

scrubber  water 71 

Baking  bread,  temperature 409 

Balance,  heat;  Tait  system 102 

Loomis-Pettibone  system 11 2 

Barometric  readings,  inches  and  millime- 
ters    505 

pounds  and  inches 506 

temperature  correction  for 202 

liars  for  grates 41,  45,  48 

Barrus  draft  gage  for  chimneys 479 

Beaume  hydrometer  comparison  with  spe- 
cific gravity 507 

Bench  firing  by  Doherty  C02  system 354 

Bituminous  coal .  . 163,  164 

producer,  economizer  on 86 

Westinghouse  producer 118 

Bituminous  producer  gas 225 

Blast  burner,  pressure  injector, 

290,  292,  293,  295 
Blast-furnace  gas,  advantages  of  producer 

gas  over 233 

analyses  of 308 

cleaning 51,  53,  55 

condensing  moisture  in 64 

heat  balance 266 

heat  recovery  by  steam  boiler 307 

power  from 233 

pie-heating  air  blast 344 

properties  of 233 

Blast  pipe  safety  device 86 

Blast  torch  for  bending  glass 295 

Blending  producer  gas  with  coal  gas 231 

Blower,  Brewster  high  pressure 152 

injector,  Eynon-Evans  and  Korting.  . .  .   144 


Blower,  pressure  blast  burners 297 

Blowers  and  fans 141 

comparison  of 145 

Boilers,  steam,  gas  fired 303 

Uiist,  producer  gas 30S 

attached  to  furnace's 308 

Lester  boiler .- 310 

Boiling-points 401,  402 

Boyle's  law  of  gases 197 

Brazing  burner,  ''  ferrofix" 292 

double 293 

heating 295 

furnace 299 

Brewster  high-pressure  blower 151,  152 

Brick  and  tile  kilns,  gas  fired 317,  320,  322 

Brick,  good,  requisites  of 490 

laying 489 

linings  for  producers 26 

required  for  lining 27 

testing  fire 484 

Brickwork,  cement  for  furnace 29 

data 487 

grouting  for  filling  behind 2S 

measurement  of 491 

Bristol  pyrometers 428 

Burette,  Tail  CO, 249 

gas  analysis,  Morehead 242 

Burner  for  test:ng  producer  gas 14 

Burners,  gas,  in  dust  r  al  uses: 

brazing,  double 293 

brazing,  "  ferrofix  " 292 

forge  work 297 

glass  bending 295 

Hawley  mixing 2XS 

injector 290 

metal  melting 294 

oven  furnace 291 

oven  heater,  Machlet 293 

singeing  cloth 294 

steam  boiler,  Kirkwood 303 

steam  boiler,  Hipp 30(5 

various  purposes 29S 

Burning  lime  and  cement 3i's 

By-product  coke-oven  gas 2(55,  2(5(5 

coke  data 1^7 

Calcining  kilns,  gas  fired 328,  337 

California  oil,  properties  and  fractions.  ...   519 

Calculations,  heat  transfer 416,  417 

pressure,  effect  on  flow 474 

specific  heat  of  gases 210,  396 

temperature,  flame 397 

Calorific  power,  fuels 169,  188 

gases,  207,  208,  221,  222,  225,  229,  231,  232 


INDEX 


527 


Calorimeter?,  gas  and  coal: 

Doherty,  ga.s 452 

Junker,  gas 450 

Lucke-J  tinker,  gas 4.~i4 

Parr  coal 454 

.Sargeant,  gas 440 

sulphur  photometer 461 

Candy  making  temperatures 40!) 

Capacities: 

fans,  various  sizes 146,  147 

flues    471 

pipe 462,  466 

pipe,  high  pressure 467,  472.  473,  474 

producers,  rating  of 30,  31 

Carbon  bisulphide  in  gas,  test  for 249 

Carbon  dioxide: 

conversion  into  carbonic  oxide 354 

cooling  producer  fuel  bed 21 

Doherty  system 354 

influence  of  in  gas 234 

properties 193,  220 

reduction  to  CO 21 

reduction,  Tait  system 98,  107 

producer  gas,  steel  furnace 394 

Carbon  dioxide,  tests  for: 

in  gas 249 

Sarco  recorder 254 

Tait  burette 249 

test  flame 13 

I'ehling  composimeter 251 

Wi.se  recorder  .  , 257 

Carbon  monoxide,  effect  of  temperature  on     10 

formed  from  CO, 21 

properties  ot 194,  206,  207,  218 

toxic  effect  of 92 

Carbonizing  oil 518 

<  Vrnent,  and  lime  burning 328,  335 

furnace  brickwork 28 

kiln,  the  Eldred  gas  fired 335 

quality  for  masonry 492 

Centrifugal  separators: 

Crossley  fan 75 

fixed  .  '. 63 

Latta  heavy  duty 61 

Latta  stratification  washer 63 

Saaler  washer 60 

tar  extractor,  rotary 78 

tar  extractor,  stationary 78 

Thiesen  washer 59 

Characteristics  of  power  gases 230,  231 

Charging  producers 86,  87 

Charles  and  Gay-Lussac's  law 197 

Checker  brick,  Jones'  crude  oil  gas  set  ...  512 
Siemens  furnace 384 


PACK 

Chemical  composition  of  power  gas 229 

Chemical  properties  of  gases 217 

Chemical  reactions: 

anthracite  producer 228 

bituminous  producer 220 

Doherty  CO:,  system 

Chimney: 

draft 478 

draft,  effect  of  temperature 479 

formula,  height 478 

general  considerations 477 

smoke  from 4sO 

weight  of  gases 479 

Circle,  area  of 159 

circumference  and  area 501 

functions,  trigonometric 502 

Classification  of  coals 162,  164 

Cleaning  producer  gas: 

condensing  moisture 64 

dust,  blast  furnace  gas 51 

influence  of 59 

removing 53 

testing  for 55 

engine  gas  requirements 80 

general  conditions 49 

scrubbers,  dry 49 

sprays  for 68 

tower 66 

water  for 70 

separators,  rev.  current 64 

tank,  receiving 51 

seal  and 71 

tar  extractors 73 

washers,  rotary 59 

Westinghouse  producer 120,  121 

Clearance  in  gas  engine  cylinders 277 

Clinkering  cement,  Eldred  gas-fired  rotary 

kiln 335,  338 

Clinkering  in  producers 3,  7 

properties  of  coals .....   176 

reduced  by  steam 16 

test  for 178 

Coal: 

ash  from,  clinkering 170,  178 

basis  for  valuation 172 

burning,  excess  air 377 

classification  of 162,  164 

comparison  for  producer 226 

depreciation  by  weathering 174,  176 

gas  coal  yields 178,  179,  182 

heat   value   compared  with   coal   con- 
sumed     181 

efficiency  of  producer 180 

efficiency  of  combustion 182 


528 


INDEX 


PAGE 

Coal: 

heat,  gas  yield 181 

rate  of  combustion 179 

unit  yield  of  gas 180 

investigation  of 172 

moisture  in 170,  174 

nature  of 162 

producing  localities 165,  167 

purchasing 171 

sampling  of 174 

sizes  of  anthracite 188 

storage 176 

testing,  Parr  calorimeter 454 

testing  in  producers,  lignites 129 

Loomis-Pettibone 170 

powdered  coal 137 

Wood  producer 96 

transportation 177 

weight  per  cubic  foot 188 

Coal  and  lignites: 

compared 177 

test  in  Wood  producer 96 

Coal  and  lignite  tests  in  Wood  producer ...     96 

Coal  gas,  blending  with  producer  gas 231 

Coefficients,  heat  conductivity 423,  424 

linear  expansion 425 

radiation 413 

Coke,  gas  from 186 

weight  per  cubic  foot 188 

Coke-oven  gas 265 

Collector  of  dust  and  moisture,  receiving 

tank 72 

Color  in  furnace  indicates  temperature ....    446 

Color  of  steel  at  high  temperatures 409 

Color  scale  for  tempering 410,  411 

Colorado  lignites,  and  producer  gas  from, 

composition 185 

Combustion : 

air  excess  effect  on 310 

carbon 12 

Doherty  CO2  system 354 

gases 207,  209 

powdered  fuel  in  producer 135 

smoke,  relation  to 480 

stages,  progressive 378 

temperatures  in  producer 10 

Combustion  in  furnaces: 

air  for 374 

coal  and  gas  firing 390 

combustion •  370 

cooling  plant  for  blast 393 

dehydrating  air  blast 391,  392 

design  of  furnaces 387 

efficiency  in  furnaces 379 


PAGE 

Combustion  in  furnaces: 

generic  efficiency 380 

heat  and  temperature 364 

ignition 372 

nitrogen,  influence  of 373 

oxidizing  and  reducing 376 

progressive  combustion 378 

recuperation 365 

recuperative  furnaces 383 

regeneration  furnaces 383 

reverberation  of  heat 390 

steel  melting  practice 394 

temperature 366 

testing  explosive  mixtures 394 

tuyeres,  size  of 383 

utilizing  sensible  heat 381 

velocity  of  flames 365 

Combustion   Utilities  Co.   carbon   dioxide 

system 107 

Commercial  gases,  analyses  of 221-233 

Comparison,    anthracite    and    bituminous 

coal  for  gas  making 224 

coals  and  1'gnites 177 

cost  and  gas  composition 189 

producer  types 32 

steam  and  gas  power 267 

Composition,  commercial  gases 221-233 

engine  gas,  variations 97 

natural  gas 219 

producer  gas  (see  Analyses) 
producer  gases : 

anthracite  and  bituminous 189 

coke 177,  187,  186 

Hirt  powdered  fuel 138 

lignites 177,  186,  187 

Loomis-Pettibone 113,  183 

Peruvian  coal 184 

Smith  producer 182 

Tait  producer 108 

tan  bark 187 

Westinghouse  producer 121 

Wood  system 96,  182 

Compression  in  gas  engines 27') 

Concrete  foundation  and  walls 487,  494 

Condensing,  blast  moisture 64 

hydrocarbons  in  gas,  avoiding 381 

moisture  in   air 391 ,  393 

Conduction  of  heat 413 

coefficients 423,  424 

principles  of 416 

relative,  of  substances 423 

substances,  of  various 414,  423 

walls,  through 417,  423 

Connections,  for  tar  separators  ........   77,  80 


INDEX 


529 


Connections,  to  producers '24 

Constant  pressure  an«l  volume  of  laws  of.  .  198 
Consumption  of  gas  engines  per  B.H.P.  .  .  2S4 
Continuous  brick  kiln,  Youngren  gas  fired.  322 
Convection  of  heat  from  surfaces  ....  420,  421 

Conversion  tables,  metric 23,  502 

Cooling: 

air  to  remove  moisture 391,  393 

effect  of  steam  in  fuel  bed 19 

gas  to  remove  moisture 64 

producer  fuel  bed  by  carbon  dioxide  ...     21 

producer  gas 49,  04 

scrubber  water 70 

surface  in  gas  engine  cylinders 277 

water  for  gas  engine  cylinders 280 

water  in  pipes 422 

Corn  cobs  as  producer  fuel 131 

Correction  of  barometric  readings  for  tem- 
perature     202 

Cost: 

erecting  producer  gas  plants 510 

several  fuel  gases  compared 189 

steam  and  gas  power 207 

Crossley  fan  as  tar  extractor 75 

furnace,  gas  fired 300 

Crucible,  analysis  of  coal 168 

Cycles  of  gas  engines 270 

Cylinder  dimensions  in  gas  engines 276 

Dalton's  lay  for  vapors 195 

Decomposition  of  steam,  influence  of  tem- 
perature on 35,  36 

Definitions 190,  195,  197,  521 

Dehydration  of  air  for  combustion    ..    391,393 

blast-furnace  gas %•  •  •     64 

Delivery  of  gas  found  with  the  Pitot  tube.    149 

Density  of  gases 199 

Design  of  furnaces,  principles  of 388 

Development  of  gas  power 260,  264 

Diesel  oil  engine,  power  from 260 

Diluent  gases .   220,  373 

I  hmensions  of  fans 147 

Loomis-Pettibone  producer  shells 114 

producers 24 

Distillation  of  crude  oil 518,  519 

water  by  gas  burner 299 

Doherty  combustion  system : 

economizer 354 

retort  bench  firing 354 

chemical  reactions 360 

advantages 361 

operation  details 362 

Doherty  gas  calorimeter 452 

Down-draft  grate 44 


Down-draft  producers,  advantages  of 93 

compared  with  up-draft 128 

Loomis-Pettibone  producer 1 08 

Smith  lignite  producer 123 

Draft  m  chimneys 478 

up-and-down,  producers 128 

Drying  of  air 391,  393 

brick  and  tile 318 

Dust,  flue,  removal  from  recuperator  pipes, 

348,  352 

Dust  in  gas,  from  Westinghouse  producer.    122 
testing  for 448 

Dust  removal  and  .analyses,  blast-furnace 

gas 53,  55 

unnecessary  for  furnace  gas 59 

Duff  producer,  gas  fired  vertical  lime  kiln.   331 

Earnshaw  absorption  pyrometer 445 

Economizer  attached  to  producer 84 

Efficiency : 
combustion  of  hot  and  cold  gas  .  . .  380,  382 

continuous  heating 380 

furnace,  specific 379 

in  Lester  steam  boiler 310 

gas  engine 284,  285 

internal-combustion  engines 260 

thermal,  of  producers 4 

Tait  producer  system 102 

Westinghouse  producer 122 

Eldred  gas  fired  cement  kiln 335 

Endothermic,  agents  in  producers 12 

combustion  agent,  CO2  as  an 361 

Engines,  gas: 

anti-pulsators 281 

character  of  gases  for 229,  230 

compression 275 

cooling  water 280 

cylinder  dimensions 275 

exhaust  mufflers 272 

foundations 272 

general  details 270 

ignition 274 

influence  of  CO2 234 

load  factors 284 

lubrication  oil  viscosity 282 

operation  conditions 264 

power 260 

pre-ignitions  in 106 

requirements 80,  96 

starting 275 

using  oil  gas 514 

Ethylene,  properties  of 219 

Exhaust  gases,  utilizing 286 

Exhaust  mufflers,  for  gas  engines 272,  274 


530 


INDEX 


Exhauster,  Brewster  Engine  Co 32 

gas  engine  as  an 143 

hot  gas 141 

suction  producers 142 

injector,  Eynon-Evans 144 

rotary,  for  Westinghouse  producer 120 

use  of,  with  gas  engines 265 

water  seal,  Tait  producer  system 98 

Expansion  of  substances  by  heat 425 

Explosions: 

blast  pipe,  preventing 88 

causes  of,  in  plant 89 

pressures  for  cool  gas 270 

Explosive  gases,  safety  seal  for  testing  .  .  .  394 

mixtures  of  gases  with  air 237 

Extractors  for  removing  tar 73 

Fans  and  blowers 141 

comparison  of 145 

Fans,  power,  capacity  and  pressure  of.  ...  146 
speed  of,  to  maintain  given  pressure...  .  160 
Feed,  George  automatic,  for  Morgan  pro- 
ducer    117 

Ferrofix  brazing  gas  burner 292 

Fery  radiation  pyrometer 441 

Filling  air  spaces  in  lining 28 

Filling  of  tower  scrubbers 67 

Film  type  of  tower  scrubber 67 

Fire-brick,  heat  conductivity 424 

producer  linings 26 

Fire  clays  and  brick: 

composition 483 

brick  testing 484 

fire-brick  shapers 485,  486 

fire-brick  joints 485 

Fire  clay,  cements  for  patching  furnaces . .  29 

mixtures,  fusion  points  of  ....  435,  436,  437 

Fireite  furnace  brickwork  cement 29 

Firing  of  kilns  and  furnaces  by  gas  .  .    312,  320 

Firing-back  in  blast  pipe 86 

First  aid  in  gas  asphyxiation  cases 91 

Flame,  oxidizing  and  reducing 377 

propagation,  velocity  of 365 

temperature 396 

testing  producer  operation 13 

velocity  of  hydrogen 262 

Flash-point  of  oils 283 

Floor   space   occupied   by   European  gas 

engines 283 

required  by  producers 25 

Flow  of  gas  in  pipes 462 

friction 193 

relation  of  pressure  to 156 

tested,  Pitot  tube 149 


PAGE 

Flow  of  gas  tested,  Venturi  meter 153 

through  orifices 465,  473 

Flow  of  steam,  measuring  the 36,  39 

Flue  and  pipe  connections 24 

Flues,  capacity  of 471 

in  steel  furnaces 395 

Flue  gas,  composition  relative  to  tempera- 
ture     371 

significance  of  CO2  in 235 

weight  of 479 

Forge  work,  gas  burners  for 297,  300 

Foundations  for  gas  engines 272 

masonry 487 

Freezing  solution,  non- 426 

Friction  loss  in  gas  pipes. . .   193,  467,  468,  469 

Fuel  basis  rating  of  gas  producers 30 

Fuel  bed,  of  producers 1 

conditions  in  down-draft  producers  ....     93 
Fuel: 

combustion,  effect  of  depth  on 374 

comparative  analyses  of 162,  164 

furnace,  coal  and  gas  compared 390 

gas  for  power  purposes 231 

industrial,  comparison  of 287 

moisture  in,  effect  on  temperature 372 

Fuels,  producer 165 

California  crude  oil 511,  518,  519 

powdered 134,  136 

yields  from  various 177,  178,  182 

required  in  furnaces  and  kilns 388 

vegetable,  for  gas  producers 132 

Fuels,  analyses,  producer: 

anthracite 183 

charcoal 189 

coke,  by-product 187 

gas-house 186 

lignite 183,  184,  185 

peat 189 

Pennsylvania  gas  coal 182 

Peruvian  acid 184 

semi-anthracite 183 

tan  bark 186 

wood 189 

Fuels,  solid: 

analysis  of  coal 168 

by-product  coke 187 

clinkering  properties 170 

coal  and  lignite 177 

coal  classification 162 

gas  coal 165 

gas-house  coke 186 

heat  value  calculations 169 

influence  of  richness 179 

moisture  in  .  .170 


INDEX 


531 


PAGE 

Fuels,  solid: 

other  fuels 187 

producer  fuel 165 

purchasing  basis 171 

sampling  coal 1 74 

storage  of  coal 1 7(1 

tar  yield  of  gas  coal 167 

tests  ot  producer  fuels 1 78 

tests  for  clinkering 178 

yield  of  gas 

Furnaces,  combustion  in 364 

design,  principles  of 387 

flue,  capacity  of 471 

gas-fired  steel  melting 394 

producer-fired  with  preheated  air 314 

Furnaces,  recuperation  and  regenerator  .  .  383 

Furnaces  and  kilns: 

adapting  producer  gas 313 

brick  and  tile  kilns 317 

ceramic  kilns 317 

gas  firing 312 

Schmatolla  kiln 325 

Schwartz  furnace 315 

Youngren  brick  kiln 322 

Galvanizing  by  producer  gas  heat 302 

Gas  analysis — see  Analysis,  gas 

Gas  coal 163,  165,  167 

Gas  Power  M'f'g.  Co.  lignite  suction  pro- 
ducer    126 

contrifugal  gas  washer 63 

Gasifying  crude  oil 518 

( iassy  atmospheres,  Vajenhelmet  for  enter- 
ing    90 

Gages,  water,    for  gas  pressure 148 

George  automatic  producer  feed 117 

( iennan  gas  fired  lime  kiln 333 

Glossary  of  terms 190,  195,  197,  521 

<  i rales  for  gas  producers: 

angle-of-repose  grate 43 

bars 41 

burning  out 48 

down-draft 44 

grid  type 43 

hanging,  Smith  producer 124 

repose  grates 45 

shaking  grate 43 

size  of  grate  bars 45 

surface  rating,  producer 30 

Green  economizer  for  pre-heating  air 349 

Grid  type  grates 43 

Grouting  brickwork 28 

Hawley  mixing  burner 288 


Heat: 

absorbing  agents  in  producers 12 

balance,  blast  furnace  and  by-product 

coke  oven 266 

cement  kiln 337 

conduction  of 413- 

absorption  by  air 420 

coefficients 423,  424 

convection 420 

principles  of 416 

relative 423 

substances 414,  423 

summary 421 

cycles  in  producers 11 

developed  affected  by  depth  of  fuel  bed .   374 

distribution,  Tait  system 102,  103 

Loomis-Pettibone  system 112 

efficiency  of  producers 4 

expansion  of  substances  by 425 

measurements 428 

radiation 411 

surfaces,  various 412,  413 

losses  through  walls 413 

recuperation  by  wrater  vaporizer  on  pro- 
ducer       83 

reduction  in  fuel  bed  by  steam 15 

related  to  temperature 364 

reverberation  or  reflection  in  furnaces  .  .  391 

units,  conversion  of 503,  504 

zones  in  the  producer 9 

Heat  phenomena: 

absorption 420 

alloy  melting-points 403 

annealing 409 

boiling-points 402,  403 

bread  baking 409 

candy  making 409 

color  scale,  tempering 409 

conduction  of  heat 413 

conduction  through  walls 417 

expansion  due  to  heat 425 

freezing-point 402 

heat  insulators 425 

industrial  operations 406,  408 

kind  of  gas 400 

loss  by  radiation 422 

melting-points 401,  403,  404,  405 

metallurgical  temperatures 407 

non-freezing  solution 426 

radiation  of  heat 411 

relative  heat  conductivity 423 

specific  heat  of  gases 396 

steel  works  temperatures 407 

temperature  of  flames 396t  397 


532 


INDEX 


Heat  phenomena : 

tempering 409 

transfer  of  heat 416,  423 

Heat  recovery 288,  307,  365 

blast-furnace  gas 344 

flue  gas 346 

furnace  gas 352 

heating  furnaces 308 

steam  boiler 307 

water  gas  sets 350 

producers,  gas 3 

Schmatolla  kiln 325 

Heat  value,  gases,  207,  209,  221,  222,  225,  229, 

231,  232,  446 

coal,  calculating 169 

related  to  efficiency  as  fuel 176 

relation  to  rate  of  combustion,  etc  .  ..   179 

tested  by  Parr  calorimeter 454 

with  gas 446 

lost  in  producer 6 

Heating,  continuous,  efficiency  of 380 

furnaces,  recovery  of  heat   from,    steam 

boiler 308 

metal  plates  for  bending 299 

metallurgical  gas 287 

water  by  engine  exhaust  gases 286 

Heraeus-Le  Chatelier  pyrometer 439 

Herrick  pressure  gas  producer 122 

Hirt  powdered  fuel  producer 136 

High-pressure  blower,  Brewster 151,  152 

power  required 150 

Holder,  gas,  used  with  gas  engines 265 

Holders,  gas,  space  occupied  by  . 25 

Horse-power  of  gas  engines,  effect  of  alti- 
tude upon 285 

Hot-blast  stove  for  pre-heating  air 344 

Hot  gases,  exhaust  for  moving 141 

Hydrocarbons  in  gases 193,  207 

Hydrogen,  cause  of  pre-ignition  in  engines, 

97,  262 

properties  of 194,  206,  207,  217 

Hydrometer  compared  with  specific  gravity  507 

Ignition,  gas  engine  charge 274 

lighting  furnaces 390 

temperature,  gaseous  mixtures 205 

temperatures  of  fuel 372 

Illuminants  in  gases 193 

Impurities  in  producer  gas 49 

testing  for 249 

Indicator  card  with  blast  furnace  and  pro- 
ducer gas 271 

Industrial  gas,  fuels,  analyses  of 221-233 

cost  and  composition 189 


Industrial  gas,  uses  for 115 

Industrial  gas  applications: 

blow  torch  for  blast 295 

burners 290 

comparison  of  fuels 287 

"ferrofix"  brazing  head 292 

forge  work 297 

general  heating  burner 296 

Machlet  japanning  burner 293 

pressure  blowers 152,  297 

recovery  of  heat 288 

singeing  burner 294 

soft  metal  melter 294 

steam  boiler,  firing 303 

Lester 310 

Rust 308 

waste  gas 307 

various  metallurgical 298 

Injector  blowers  and  exhausters 144 

burner  for  industrial  gas 290 

Insulation  of  shell 27 

Insulators,  heat,  relative  values 425 

Insurance  requirements  for  producers.  ...  88 

Internal-combustion  engines,  efficiency  of.  261 
Isothermal  expansion  and  compression  of 

gases 1 98 

Joints  in  laying  fire-brick 485 

Jones'  oil  gas  producer  set 511 

Junker  gas  calorimeter 448 

Kilns: 

advantages  of  gas  firing  .  .  .  .* 317 

brick  and  tile,  gas  firing  of 317 

for  burning  lime  and  cement: 

burning  lime  by  natural  gas 329 

calcining  kiln 337 

calcining  lime 328 

cement  kilns,  rotary 335 

clinkering  kiln 338 

Eldred  cement  kiln 335 

German  lime  kiln 333 

Hawley  down-draft,  burners  for 288 

rotary  lime  kilns 332 

vertical  lime  kilns 330 

Kilns  and  furnaces 312 

Kirkwood  burnr  for  steam  boilers 303 

Lackawanna  Iron  Co.  engine  gas  require- 
ments    81 

Latta  heavy  duty  centrifugal  gas  washer.  .  61 

Laws  of  gases,  physical 197 

Lester  boiler,  gas  fired 310 


INDEX 


533 


Lignites 102,  1(54 

analyses  of 1 29 

gas,  Loomis-Pettibone  producers 183 

grate  bars  for 4(> 

suction  producer,  (las  Power  M'f'g.  Co..    12(> 

Lignites  and  coals  compared 1  77 

Lime  and  cement  burning 328 

influence  on  producer  dimensions 25 

Linings,  fire-brick 26 

Liquids,  weight  and  specific  gravity  of  ...   510 

Load  factors  of  gas  engines 284 

producers 31 

Loomis-Pettibone  gas  producer  system  ...    108 

producer  gas 223 

Loss  in  power: 

and  pressure  by  friction  in  pipe  .  .     468,  469 

from  CO,  in  flue  gas 235,  236 

producer  gas  system 268 

Loss  of  heat,  due  to  CO  in  flue  gas.  .  .   372,  375 

due  to  excess  air 375 

due  to  steam  in  fuel  bed 20 

in  producer 16,  18 

producer  fuel 6 

walls  through 413,  423 

Lowe  system  of  gasifying  crude  oil 511 

Lubrication  and  oils 282 

Machlet  gas  burner  for  ovens 292,  293 

Maintenance,  relative 27 

Mallets  rotary  tar  extractor 75 

MM  s(  ii  i  ry  construct  ion : 

cement 4-j2 

concrete  walls 494 

foundations 487 

laying  brick 489 

measurement  of  brickwork 491 

mortar 488 

qualities  of  good  brick 490 

stonework 491 

tank  wall 489 

Materials:   Fireclay,  masonry  weights  and 

rope 483 

Maximum  temperature  conditions 399 

Measurement  of  brickwork 491 

steam 36 

Measures,  metric,  conversion  of 502-506 

Melting  furnace,  practice,  steel  gas  fired .  .  .   394 

Schwartz  gas  fired 314 

soft  metal  burner  for 294 

Melting-points  ...   401,  402,  403,  404,  405,  407 

fire  clay  mixtures 435,  436,  437 

Metal  melting,  gas  burner  for 294 

Metals,  melting-points  of .  .          .   402,  403,  404 
Metallurgical  operations,  gas  fuel  for 287 


Meter,  steam,  St.  John  recording 3(5 

Sargent 39 

Methane,  properties  of 194,  207,  21  s 

Method  of  analysis,  Orsat  apparatus 239 

Metric  conversion  tables 502 

Mexican  lignites,  composition 185 

Misting  spray  for  tower  scrubbers 68 

Mixed  gas,  analyses  of 223 

ignition  temperature  of 205 

Loomis-Pettibone  producer 1 13 

Mixing  of  gas  for  perfect  combustion 368 

Moisture,  boiler  coal 170 

coal  content 1 70.  1 74 

removal  from  gas 64 

Molecular,  heats  of  gases 208 

volumes  of  gases 208 

weights  of  gases 214 

Morehead  gas  burette 242 

Morgan  producer,  firing  billet  furnace.  .  .  .  317 

George  feed  for 117 

Mortar  for  masonry  construction 488 

Moving  air  in  pipes,  power  lost  in  friction, 

468,  469 

rotary  hot  gas  exhauster 141 

suction  producer  exhauster 142 

testing  blast 145 

Moving  gases: 

area  of  orifices 159 

capacity  of  fans 146 

comparison,  blowers  and  fans 145 

discharge  through  pipes 156 

influence  of  temperature 154 

injector  blowers  and  exhausters 144 

measuring  by  Pitot  tube 149 

Yenturi  meter 153 

pressure  due  to  speed  of  fan 1 60 

pressure,  inches  and  ounces 158 

Mufflers  for  gas  engine  exhaust 272,  274 

Natural  gas,  comparative  fuel  value 287 

cost  and  composition 

lime  burning 329 

measurement 472 

properties  of  219,  222 

Nitrogen,  influence  upon  combustion 373 

properties  of 194,  220 

Nix-Frost  oil  gas  suction  producer 513 

Noises  in  gas  engines 272 

Non-freezing  solutions 426 

Nozzles  for  tower  scrubber  misting  spray . .  69 

Oils: 

comparative  fuel  value  of 287 

cost  and  composition 189 


534 


INDEX 


Oils: 

crude,  for  gas  making 518,  519 

fractions  California 519 

Texas 519 

lubricating  for  gas  engines 282 

producer  gas  systems 511 

Operation  of  gas  producers: 

burning  out  grates 48 

clinker, 3,  7 

continuous  operation 26 

endothermic  agents 12 

fire-brick  linings 26 

flue  and  pipe  connections 24 

fuel  bed 1,8 

Gas  Power  M'f 'g  Co.,  lignite 126 

grates  for  producers 41 

grouting  and  cement 28 

heat  cycles 11 

efficiency 4 

recovery 3 

zones 9 

Hirt  powdered  fuel  producer 137 

lignite  fuel  grates 46 

load  factor 31 

Loomis-Pettibone  producer 112 

losses  in  producer 6 

Marconet  powdered  fuel  producer 138 

meters  steam,  St.  John 36 

Sargent 39 

Morgan  producer 117 

powdered  fuel  producers 134 

rating 30 

reactions 9 

repairs  and  maintenance 27 

shell  insulation 27 

shells  of  producers 26 

size  of  producer  shell 24 

Smith  producer 125 

space  occupied 25 

steam  cooling 15 

excess 35 

supply 33 

temperature 35 

suction  producer  types 32 

Tait  producer  system 104 

test  flame  for  regulation 13 

up-and-down  draft  types 31 

water  seal  producers 33 

weights  of  producers 25 

Westinghouse  producer 121 

Wood  producers 94 

wood-fuel  suction  types 131 

Orifices,  area  of 159 

thin  plates,  gas  discharge  through 465 


Orsat  analysis  apparatus 238 

Oven  or  furnace  gas  burner .  .   201 ,  301,  302,  303 

Oxidizing  and  reducing  flames 377 

Oxygen    administration    in    asphyxiation 

cases 91 

properties  of 194,  220 

Parr  coal  calorimeter 454 

Patching  furnace  brickwork 29 

P.  &  A.  tar  extractor 74,  77 

Peruvian  coal,  and  producer  gas  from,  com- 
position      184 

Petrizilke's  Orsat  apparatus 238 

Physical  properties  of  gases 190 

Pipe: 

bends,  influence  upon  pressure 467 

branch  from  mains,  diameter  of 466 

capacity  of 462,  466 

high  pressure 467,  473,  474 

friction  loss  in  gas 467 

sizes  for  required  capacities 464 

steam,  condensation  and  radiation  in, 

420,  421 

weight  of,  round  galvanized  gas 470 

Pipette  for  gas  analysis 241 

Pitot  tube  for  measuring  flow  of  gas 149 

Plant,  brick  kiln,  producer  gas  fired 320 

Pole's  formula  for  capacity  of  gas  pipe  .  .  .  462 
Powdered  fuel  producers: 

Hirt,  American 136 

Marconet,  French 138 

producers 134 

economizer  on 85 

Power  &  Mining  Machinery  Co.  producer, 

the  Staub " 116 

Power  from  gas : 

blast  furnace  gas 266 

coke  oven  gas 265 

comparison,  steam  and  gas 267 

development 260,  264 

operation  conditions 264 

pie-ignition  due  to  H 262 

quality  of  gas 261 

stand-by  losses 268 

suction  pipe 265 

vapor  aqueous 263 

Power  plant  requisites,  gas  driven 261 

Power  required,  delivering  air 150,  156 

fans,  operation  of 146,  147 

Power  units,  metric,  conversion  of 508 

Pre-heated  gases,  influence  on  efficiency  . .  379 
Pre-heating  air: 

blast  stoves  .  344 


INDEX 


535 


Pre-heating  air: 

combustion  purposes 381 

Green  economizer 349 

producer  gas  firing 313,  314 

Sturtevant  pre-heater 346 

triple  recuperation 352 

Pre-ignitions  due  to  hydrogen 262 

Pre-ignitions  in  gas  engines  causes  for, 

106,  205,  274 

Pressure: 

barometric , 201 

blowers,  for  blast  burners 297 

conversion  of  ounces  and  inches 158 

delivered  by  fans 146,  147 

fluctuations  in  gas  engine  supply 281 

high,  capacity  of  pipe  under, 

467,  472,  473,  474,  476 
influence  of  differential  in  tar  extractors.     74 

influence  on  gas  flow 463,  465 

laws  of  gases 197 

lost  in  pipe  by  friction 467 

recorder,  blast 148 

regulation    for   engines    by    water    seal 

exhauster 100 

relation  to  flame  temperature 365 

volume  of  gases 145,  152,  156 

power  required 151 

scale,  ounces  and  inches 506 

speed  of  fan  to  maintain  given 160 

steam  for  producer 34 

Pressure  producers : 

comparison  with  suction 32 

Herrick  producer 122 

insurance  regulations 88 

Morgan  producer 117 

Smith  lignite  producer 123 

space  occupied 25 

Wood  system 94 

Principles  of  heat  transfer 416 

Principles  of  producer  operation: 

Gas  Power  Co.  lignite 126,  128 

Herrick  producer 122 

Hirt  powdered  fuel  producer 136 

Loomis-Pettibone  system 108,  112 

Marconet  powdered  fuel  producer 138 

powdered  fuel  producers 134 

Smith  lignite  producer 123 

Tait  producer  gas  system 98 

\\Cstinghouse  producer 118 

Process  and  apparatus,  Loomis-Pettibone 

producer 108 

Producer  gas  from  oil,  systems : 

Amet-Ensign  type 515 

gasifying  oil 518 


PAGE 

Producer  gas  from  oil,  systems: 

Jones'  improved  type 511 

Nix-Frost  suction  type 513 

Producer  gas,  cost  of  erecting  plants 510 

reactions  concerning 9 

Producer  types 93 

Properties  of  fire-brick 483 

Properties  of  gases,  chemical : 

analyses  of  producer  gas 223 

anthracite  producer 227 

bituminous  producer 225 

blast  furnace  gas 233 

carbon  dioxide  in  gas 234 

classification 217 

combustion  gases 217 

diluent  gases 220 

explosive  mixtures 237 

industrial  gases 221 

mixing  producer  and  coal  gas 231 

power  gas 232 

solubility  in  water 237 

vapor  saturation 236 

water  gas 232 

Properties  of  gases  for  gas  engines 230 

Properties  of  gases,  physical : 

calorific  power 207 

general 190 

ignition  temperature 205* 

laws 197 

specific  gravity 216 

specific  heat 210 

vapors 195 

weights  and  volumes 214 

Proximate  analysis  of  coal 168 

Puddling  furnace,  steam  from  waste  heat.  308 
Pulsation  prevented  by  receiving  tank  ...  72 
Pumps  supplying  engine  cylinder  cooling 

water 281 

Purchasing  of  coal 171 

Purifying  producer  gas 49 

Pyrometers: 

Bristol  electric 428 

color  of  incandescence 410 

Earnshaw  blue-glass 445 

Fery  radiation  electric 441 

Heraeus-Le  Chatelier  electric 439 

Seger  fire  clay  cones 435 

Queneau  triple  recuperation,  heating  air  by  352 

Quality  of  gas,  for  gas  engines 96,  261 

influenced  by  steam 17 

Quality  of  producer  gas  for  gas  engines. .  ,     80 

Radiation  of  heat  .  .411 


536 


INDEX 


Radiation,  coefficients  of  radiation 413 

loss  through  walls 413 

ratios  radiation 412 

Stefan's  law 411 

surfaces,  various 411,  412 

Radiation,  pyrometer,  Fery 441 

absorption  pyrometer,  Earnshaw 44") 

Raie  of  combustion 369,  370 

Rating  of  gas  producers 30 

Reactions  in  a  producer 9 

anthracite  producer 22S 

bituminous  coal  producer 226 

fuel  bed  influenced  by  its  depth 374 

influence  of  steam  excess  on 35 

Receiving  tank  for  removing  impurities  in 

gas 71 

Recording  pyrometer,  Bristol 433,  434 

Recovery  of  heat 2,s.s 

blast-furnace  gas,  steam  boiler 307 

engine  exhaust  gases 286 

kilns,  waste  heat  in 319 

puddling  furnaces 308 

Schmatolla  kiln 325 

sensible  heat  in  gases 381 

Recuperation,  heat 365 

furnaces 383 

Loomis-Pettibone  producers Ill 

producer  heat 83 

Recuperators  of  Doherty  retort  benches.  .  .   358 

Reducing  and  oxidizing  flames 377 

Reduction  of,  CO2  to  CO 21 

pipe  weights  and  capacities 466,  471 

Refrigerating  machines  to  cool  gas 64 

Refrigeration  of  air  to  remove  moisture,  391,  393 
Regulation,    engine    gas    supply    by    ex- 
hauster      100 

Smith  producer,  steam  supply  ....   125,  126 

Tait  producer,  operation 104 

Regenerative      high      temperature      kiln, 

Schmatolla 325 

Regenerative  and  recuperator  furnaces.  .  .   383 
Relative   values   of   heat  conductors   and 

insulators 424,  425 

Removal  of  tar,  testing  the  apparatus  for.     74 

Repairs  to  producers 27 

Repose  grates 43,  45,  46 

Requirements  for  gas  engines 96 

Requisites  for  gas  power  plant 261 

producer  gas  for  gas  engines 80 

Rescue  in  gassy  atmospheres,  Vajen  helmet 

for 90 

Retort  bench  firing,  Doherty  system 354 

Retort  temperature  tested  by  Fery  py- 
rometer . ,  443 


Reverberation  of  heat  in  furnaces 391 

Reversed  current  gas  washers 64 

Reversing  valves  of  Siemen's  furnace, 

386,  387,  389 

Ribbon  burner  for  singeing  cloth 294 

Riter  Conley  Co.'s  Hirt  powdered  fuel  pro- 
ducer    136 

Rope,  strength  of 499 

length  and  weight 500 

Rotary,  centrifugal  washers 59 

centrifugal  tar  extractors 78 

hot  gas  exhausters 141 

lime  kiln 332 

Rust  water  tube  boiler,  producer  gas  fired .  308 

Saaler  centrifugal  gas  washer 60 

Safety  device  on  blast  pipe 86,  88 

St.  John  recording  steam  meter  .  .  . 36 

Sampling,  coal 1  74 

gas,  can  and  aspirator 245-24S 

Sarco  CO2  recorder 254 

Sargent  dust  determinator 55 

gas  calorimeter 446 

steam  meter 39 

Saturated  air,  moisture  in 201 

Sawdust  as  producer  fuel 131 

Scrubber,  lignite  suction  producer 127 

tower  type lid 

water  supply  for 70 

Scrubbing  producer  gas: 

blast-furnace  gas 51 

centrifugal  rotary  washers 59 

condensing  moisture 64 

dry  strubbers 51 

dust,  testing  for 55 

engine  gas  requirements 80 

influence  of  dust 59 

receiving  tank 51 

removing  dust 53 

reversed  current  separators 64 

seal  and  receiver  tank 71 

sprays  for  scrubbers 68 

tar  extractors 73 

tower  scrubbers 66 

water  for  scrubbers 70 

Schmatolla  high-temperature  fired  kiln     .  324 
Schwartz  producer  gas  fired  melting  fur- 
nace     314,  315,  316 

Seal,  testing  gas  when  purging 394 

wash  box  for  tower  scrubbers 71 

Westinghouse  producer 1 20 

Seger  fire-clay  cones,  pyrometer 435 

Sensible  heat,  recovery  of 381 

Separator,  tar,  rotary  centrifugal ........  78 


INDEX 


537 


PAGE 

Shaking  grate 43 

Shapes  of  fire-brick 485,  486 

Shavings  as  producer  fuel 131 

Shell  dimensions;  of  producer 26 

insulation 27 

Siemen's  regenerator  furnace 383 

temperature 406 

Singeing,  ga^  burner  for 294 

Sizes,  gas  pipe  forgiven  capacity.  .  .  .   464,  465 

grate  bars 45 

producers 24 

Smith  lignite  producer 123 

Smoke,  constitution  of 480 

gas  producers,  avoiding 132 

Smooth-on  cement  for  fire-clay  shapes.  ...     30 
Snow  Steam  Pump  Co.  engine  gas  require- 
ments      80 

Solid  fuels 162 

Solids,  specific  heat  of 213 

Solubility  of  gases  in  water 237 

rvmnd,  velocity  of 193 

Space  occupied  by  producers 25 

Loomis-Pettibone  producers 114 

Specifications  for  gas  'to  be  used  in  gas 

engines 80,  81 

Speed,  fan  to  maintain  given  pressure  ....    160 

various  sizes  of  fans 146,  147 

Spray  type  of  tower  scrubber 67,  68 

Specific  gravity  of  gases 221 

influence  on  capacity  of  main 472,  476 

liquids 507,  5 1 0 

solids 508 

water  at  various  temperatures 509 

weight  of  gases  and 509 

Specific  heat : 

calculating  for  gases 210 

gases  at  various  temperatures 21,  23 

solids 213 

tables  of 211 

temperature  influence  upon 22,  396 

vajiors 212 

water  at  various  temperatures 213 

Stand-by  losses  in  producer  engine  power 

plant .268 

Standard  volumes 199 

Starting-up,  a  gas  engine 27") 

Tait  producer 104 

Staub  suction  gas  producer 116 

Steam  and  gas  power,  comparison  of 2(57 

Steam : 

blowers  and  exhausters 144 

boilers,  gas  fired 303,  308,  310 

cooling  fuel  bed 15,  19 

decomposition  in  fuel  txnl 15 


Steam: 

excess,  result  of  our  gas 35 

in  gas,  properties  of 220 

influence  of  on  gas 17 

meter,  St.  John  recording 36 

Sargent 39 

pipe,  heat  conductivity  of 420,  421 

separator  as  moisture  remover 64 

supply  for  producer  fuel  bed 33 

supply  regulation  on  Smith  producer,  125, 126 

temperature  reduced  by 16,  19 

vaporizers  °n  producer 83 

Steel,  manufacture,  producer  gas  for 233 

melting  furnace  practice 394 

works  temperatures 406,  407,  408 

Stefan's  law  of  sheet  radiation 411 

Stoking  producer  fuel  bed 2 

Stonework  masonry 491 

Storage  of  coal 176 

Stoves,  hot  blast,  for  pre-heating  air  .....  344 

Sturtevant  air  pre-heater 346 

Suction  producers: 

exhausters  for 142 

gas  from 224 

Gas  Power  Co.,  lignite 126 

insurance  requirements 89 

Nix-Frost  oil  gas 513 

space  occupied  by 25 

Staub  type 116 

water  used  by  scrubber 71 

Westinghouse 120 

wood  fuel  producers - 131 

Sulphur,  contained  in  coal 169,  171,  173 

engine  gas 82 

steel  furnace  producer  gas 395 

test  with  Parr  calorimeter 461 

Sulphureted  hydrogen  in  gas,  test  for  ....  249 

Tait  CO2  burette 249 

producer  system,  advantages 96,  98 

test  flame  for  producer  gas 14 

Tan   bark,    composition    of   producer   gas 

from 187 

Tank  wall  of  brick 489 

Tar  extractors 73 

centrifugal  rotary 78 

fixed  centrifugal 75 

P.  &  A.  type 77 

P.  &  A.  tests  on 74 

Tar,  smoke  containing 481 

wood  fuel  in  producers 132 

yield  of  gas  coal 167 

Tarry  matter  in  gas 220 

Taylor  producer,  pressure  type 94 


538 


INDEX 


Temperature : 

air  excess,  effect  of 375 

chart  for  reduction  of  scales 23 

combustion 366,  368,  370,  372 

correction  for  barometer  readings 202 

dryness  of  fuel  affecting 372 

furnaces  tested  by  color 445 

high,  in  Schmatolla  kiln 325 

ignition  of  gaseous  mixtures 205 

influence  on,  aqueous  vapor  tension  201,  204 

combustion 12,  14,  18 

composition  of  burning  gas 371 

moving  air 154 

reducing  steam 19 

specific  gravity  of  water 509 

specific  heat  of  gases 22 

vapor  tension  and  solubility 237 

laws  of  gases 1 97 

producer 8 

effect  upon  CO 10 

reduction  of 12 

reduction  in  fuel  bed  by  steam 15 

related  to  heat 364 

steam,  effect  of,  on  reaction 35 

steam  for  producer 35 

testing,  pyrometers 428 

Temperatures : 

annealing 409 

boiling-points 401 

flames 396,  397 

freezing-points 402 

fusion  of  alloys 403,  404 

industrial  operations 402,  406,  408,  409 

influences  affecting 398,  399 

kind  of  gas  influencing 400 

maximum 399 

melting 401-405 

specific  heat  and 396 

steel  works 407 

tempering 409 

Tempering,  metal  baths  for 406 

Tension,  of  vapors 237 

aqueous  vapor 200,  201,  204 

Terms,  technical,  glossary  of 521 

Test  of  gas  engine  using  oil  gas 513 

Test  flame,  Tait  producer 102 

Testing,  blast  volume  and  pressure: 

coal  for  clinkering 178 

dust  and  tar  in  gas 448 

dust  in  flue  gas 58 

fire-brick 484 

heat  value 446 

impurities  in  gas 249 

pipes  when  filling  with  gas 394 


Testing  tar  in  gas 73 

temperatures 428 

Tests,  coal  in  producers: 

effect  of  temperature  of  steam 36 

gas  engines 284 

lignite  fuel 129 

Loomis-Pettibone  producer 170 

powdered  coal 137 

Wood  system 96,  177 

Texas  lignites,  composition 184,  185 

oil  distillation  fractions 519 

Thermoelectric  pyrometers 428,  439 

Thermometer  scales  compared 506 

Thiesen  centrifugal  gas  washer 59 

Tightness  of  producer  shell 26 

Tower  scrubbers,  types  of 6(> 

^Troubles,  locating,  Tait  system 106 

Tuyeres,  Herrick  steam-blown  producer..  122 

size  due  to  heated  gas 383 

Types  of  producers : 

down-draft  type 93 

Herrick  producer 122 

Hirt  powdered  fuel  producer 136 

lignite  suction  producer 126 

Loomis-Pettibone  system 108 

Marconet  powdered  fuel 1 38 

Morgan  producer 117 

powdered  fuel  producers 134 

Smith  lignite  producer 123 

Tait  producer !»('» 

Westinghouse  double  zone 1 1 S 

Wood  producer 94 

wood-fuel  suction  producer 131 

Types,  up-and-down  draft,  comparison  of.  31 

suction  and  pressure  compared 32 

water  seal  producers 33 

Uehling  gas  composimeter 25 1 

Umbrella  spray  nozzle 70 

Underwriter's  rules  regarding  producers  . .  88- 

U.  G.  I.  form  of  Orsat  apparatus 241 

Up-draft  lignite  suction  producer.  .  .  .    126,  12& 

Uses  for  producer  gas 315 

Loomis-Pettibone  producer 115- 

Utilization,  blast-furnace  gas  from  steam 

boilers 307 

engine  exhaust  gases 286 

heat  in  producer  gas 288 

sensible  heat 381 

Valves,  reversing,  Siemens'  regenerative 

furnace 386,  387,  3S!) 

Vapor,  aqueous,  influenced  by  tempera- 
ture .  155> 


INDEX 


539 


PAGE 

"Vapor,  specific  heat  pt 212 

saturation  and  tension 236 

Vapors,  properties  of 195 

Vaporizers,  on  producer  shell 83 

Westinghouse  producer 118 

Vajen  helmet   for  entering  gassy   atmos- 
pheres    90 

Velocity,  combustion,  effect  on  tempera- 
ture    369 

flame  propagation 365 

gases,  anemometer  for  testing 148 

head  of  flowing  gas: 

Pitot  tube 149 

Venturi  meter 153 

Venturi  meter  for  measuring  flow  of  gas.  .  153 

Vertical  lime  kilns,  gas  fired 330,  333 

Viscosity  of  mineral  oils 282 

Vitrex  for  repairing  fire  clay  shapes 29 

Volume,  of  gas  delivered: 

Pitot  tube 149 

Venturi  meter 153 

laws  of 197 

relation  to  pressure 145,  150,  152,  156 

weight  of  gases,  table  of 215 

Volumetric  specific  heat  of  gases 212 

Walls,  conduction  of  heat  through  ...  417,  423 

Washburn  &  Moen  producer  gas 223 

Wash-box  or  seal  on  scrubbers 71 

Washers,  gas: 

Crossley  fan 75 

fixed  centrifugal 63 

Latta  heavy  duty 61 

Latta  stratification 63 

lignite  suction  producer 128 

method  of  operation 59 

reversed  current 64 

Saaler  washer 60 

Washington  lignites,  composition 185 

Waste  gases,  industrial,  for  boiler  firing. . .  307 
Water : 

cleaning  and  reusing 71 

cooling  gas  engine  cylinders 280 

pre-heaters  and  vaporizers  on  producer  .  83 

required  by  lignite  producers 131 

specific  heat  at  various  temperatures. .  .  213 

supply  for  tower  scrubbers 70 

temperature  effect  on  specific  gravity  . .  509 


Water  gas,  making,  drying  blast  air  in  ...   392 

Loomis-Pettibone  producers 112 

properties  of 232 

sets,  Green  air  pre-heater  for 350 

tar  in 75 

Water  vapor  in  air,  condensing  of. .  .  .   391,  393 

properties  of,  in  gas 220 

tension  of,  in  gas 201,  204 

Water-cooled  grates 44,  45 

Water  seal  producers 33 

Weights : 

air,  at  various  temperatures 155 

atomic  and  molecular 214 

chimney  gases 479 

coal  and  coke 188 

corrugated  iron 499 

engines,  gas,  European 283 

galvanized  iron  gas  pipe 470 

gases  per  1000  cu.ft 509 

liquids 507,  510 

producer  sets 25 

rivets 498 

sheet  iron 496,  497 

Weights  of  substances 508 

various  materials 494 

Weight  and  volume  of  gases 214 

Westinghouse  bituminous  double-zone  pro- 
ducer      118 

Westinghouse  Machine  Co.  engine  gas  re- 
quirements       80 

Wise  CO2  recorder 257 

Wood,  R.  D.,  &  Co.,  engine  gas  require- 
ments      81 

pressure  producers 94 

producer  gas 229 

Wood-fuel  suction  producers 131 

Words,  technical,  glossary  of 521 

Works,  details: 

vaporizers  and  economizers 83 

charging  producers 86 

safety  devices 86 

insurance  requirements 88 

gas  explosions 89 

gas  asphyxiation 91 

Yield  of  producer,  from  various  coals 179 

influenced  by  steam 17 

Youngren  brick  kilns,  gas  fired 322 


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FUELS    USED 

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Cleaning  effect  meets  all  gas  engine 
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SIM  PLICIT  Y        ACCURACY 
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BUILDERS  IRON  FOUNDRY 

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•fr 


I 


By  the  Same  Author 

cj> 

8vo,  Cloth,  142  Illus.,  460  pp.,  Net  $4.50   I 

________________  ____________________^_^^______^^^_^___^_____       •§• 

f 

Handbook    of 

American 

Gas-Engineering 

Practice 

By   NISBET  LATTA  | 

*3  * 
Mtmber  American  Gas  Institute;  Member  American  Society  Mechanical  Engineer     ]\ 

——=———  «fr 

* 

CONTENTS.  Water  Gas  Manufacture:  The  Generator.  The  Car-  J 
buretter.  The  Superheater.  Wash-Box  and  Tar.  Scrubbers.  Condensers.  * 
Purifiers.  Exhausters.  Station  Meters.  Holders.  Details  of  Works  Opera- 
tion.  Gas  Distribution:  Napthalene.  Mains.  Services.  Consumers'  Me- 
ters. Pressure.  House  Piping.  Appliances.  General  Technical  "Data:  Prop- 
erties of  Gases.  Steam.  Mathematical  Tables.  Conversion  Factors.  Pipe 
and  Miscellaneous  Data. 

Engineers  and  managers  of  American  gas  works  have  long  looked  forward 
to  a  treatise  upon  gas  engineering  practice  which  should  be  devoted  to  methods 
used  in  this  country,  and  it  has  been  the  purpose  of  the  author  to  supply  this 
demand.  It  is  the  first  book  of  this  character  which  has  as  yet  been  published 
in  America,  and  therefore  must  be  regarded  as  a  necessary  addition  to  every 
gas  engineering  library.  Part  I. — Water  Gas  Manufacture.  The  treatment 
of  this  subject  is  distinctly  practical,  and  will  be  found  exceedingly  useful  to 
water  gas  technicians,  the  information  being  directly  applicable  to  the  opera- 
tion of  water  gas  plants,  from  generator  to  holder.  Part  II. — Gas  'Distribu- 
tion. This  division  would  as  well  apply  to  the  distribution  of  any  kind  of  gas, 
embracing  topics  from  mains  to  appliances.  It  includes  much  material  never 
before  published.  Part  III. — General  Technical 'Data.  Information  of  value 
upon  the  properties  of  gases  and  steam,  mathematical  tables  such  as  powers 
and  roots,  factors  for  conversion  of  French  and  English  weights  and  measures, 
pipe  dimensions  and  specifications,  etc. 


D.  VAN  NOSTRAND  COMPANY 

Publishers  and  Booksellers 
23   Murray   and   27    Warren   Sts.,   New  York     * 

V 

fr4.HMi.»^4.4.»4.»4'»4^»4-4-+»»»»»»»4-»»4.^^a.<.<.».i.»»<^»4.»^4>4.»<.4.»»4.4»t 


D.  VAN    NOSTRAND    COMPANY'S 


LIST    OF    BOOKS 

ON 


PRODUCER    GAS 


AiNTD 


Gas,    Gasoline    and    Oil 

ENGINES 


ALLEN,  HORACE.  How  to  Design  a  Gas  Engine.  With  full  working  draw- 
ings for  a  7  B.  H.  P.  gas  engine.  20  illustrations.  4to.  cloth.  40  pp. 
[Manchester,  1907.  net,  $1.00 

—  Modern  Power  Gas  Producer  Practice  and  Applications.     A  practical 
treatise  dealing  with  the  gasification  of  various  classes  of  fuels  by  the 
pressure  and   suction   systems   of  producer.      136  illustrations.      I2mo. 
cloth.    334  pp.    London,  1908.  net,  $2.50 

—  Gas  and  Oil  Engines.    A  treatise  on  the  design,  construction  and  work- 
ing  of    internal   combustion    engines.      240    illustrations.      8vo.      cloth. 
548  pp.    Manchester,  1907.  net,  $4.50 

ASKLING.  C.  W..  and  ROESLER,  E.  Internal  Combustion  Engines  and  Gas 
Producers.  178  illustrations.  6x9.  cloth.  305  pp.  London,  1912. 

net,  $4.50 

AUDEL'S  Gas  Engine  Manual.  A  practical  treatise  on  the  theory  and  man- 
agement of  gas,  gasolene,  and  oil  engines.  156  illustrations.  8vo.  cloth. 
465  pp.  Xew  York,  1908.  $2.00 

EOTTONE,  S.  R.     Magnetos  for  Automobilists :  How  Made  and  How  Used. 

A  handbook  of  practical  instruction  in  the  manufacture  and  adaptation 
of  the  magneto  to  the  needs  of  the  motorist.  Second  Edition,  enlarged. 
S2  illustrations.  i2mo.  cloth.  n8pp.  London,  1909.  net,  $1.00 


2          /;.    I'AN  NOSTRAND  COMPANY'S  LIST  OF  BOOKS 

BREWER,  R.  W.  A.  Motor  Car  Construction.  A  practical  manual,  with 
notes  on  wind  resistance  and  body  design,  for  the  use  of  engineers, 
students  and  motor  car  owners.  78  illustrations.  I2mo.  cloth.  247 
pp.  London,  1912.  net,  $2.00 

BUTLER,  EDWARD.  Carburettors,  Vaporizers,  and  Distributing  Valves  Used 
in  Internal  Combustion  Engines.  100  illustrations.  8vo.  cloth.  187  pp. 
London,  1909.  $2.00 

CARPENTER,  R.  C.,  and  DIEDERICHS,  H.  Internal  Combustion  Engines; 
Their  Theory,  Construction,  and  Operation.  Third  edition,  corrected. 
Illustrated.  8vo.  cloth.  611  pp.  New  York,  1912.  net,  $5.00 

CONTENTS:  Introduction,  Definitions,  and  Classification,  Indicated  and  Brake 
Horse-Power.  Thermodynamics  of  the  Gas  Engine.  Theoretical  Comparison  of 
Various  Types  of  Internal  Combustion  Engines.  Various  Events  of  the  Constant- 
Volume  and  Constant-Pressure  Cycle  as  Modified  by  Practical  Conditions.  The 
Temperature  Entrophy  Diagram  Applied  to  the  Gas  Engine.  Combustion.  Gas 
Engine  Fuels,  the  Solid  Fuels,  Gas  Producers.  Liquid  Fuels:  Carbureters  and 
Vaporizers.  The  Gas  Fuels.  The  Fuel  Mixture — Explosibility,  Pressure,  and 
Temperature.  History  of  the  Gas  Engine.  Modern  Types  of  Internal  Combustion 
Engines.  Gas  Engine  Auxiliaries :  Ignition,  Mufflers,  and  Starting  Apparatus. 
Regulation  of  Internal  Combustion  Engines.  The  Estimation  of  Power  of  Gas 
Engines.  Methods  of  Testing  Internal  Combustion  Engines.  The  Performance 
of  Gas  Engines  and  Gas  Producers.  Cost  of  Installation  and  of  Operation. 

CHALKLEY,  A.  P.  Diesel  Engines  for  Land  and  Marine  Work.  With  an 
introductory  chapter  by  Dr.  Rudolph  Diesel.  Illustrated.  6x9.  cloth. 
237  pp.  London,  1912.  net,  $3.00 

CONTENTS:  General  Theory  oi  Heat  Engines,  with  Special  Reference  to  Diesel 
Engines.  Action  and  Working  of  the  Diesel  Engine.  Installing  and  Running 
Diesel  Engines.  Testing  Diesel  Engines.  Diesel  Engines  for  Marine  Work. 
Construction  of  the  Diesel  Marine  Engine.  The  future  of  the  Diesel  Engine. 
Appendix. 

CLARK,  A.  G.  Textbook  on  Motor  Car  Engineering.  Vol.  i.  Construc- 
tion. 213  illustrations.  6x9,  cloth.  440  pp.  London,  1911.  net,  $3.00 

CLARK,  CARL  H.  Marine  Gas  Engines;  Their  Construction  and  Manage- 
ment. 102  illustrations.  S->4  x  &  cloth.  ITS  pp.  New  York.  1911. 

net,  $1.50 

CONTENTS:  Types  of  Engines.  Two-Cycle  Engines.  Four- Cycle  Engine?.  Va- 
porizers and  Carbureters  Ignition  Devices.  Ignition  Wiring.  Lubrication. 
Multiple-Cylinder  Engines.  Reversing  Mechanisms.  Propellers.  Installation. 
Operation  and  Care  of  Engines.  Power  of  Engines.  Selecting  an  Engine. 


O.Y  PRODUCER  GAS  AND  GAS  AND  OIL  ENGINES.          3 

CLERK,  DUGALD.  The  Gas,  Petrol,  and  Oil  Engine.  Vol.  I.  Thermo- 
dynamics of  the  Gas,  Petrol  and  Oil  Engine  together  with  Historical 
Sketch.  Neiv  and  Revised  Edition.  121  illustrations.  5  plates.  8vo. 
cloth.  380  pp.  >,evv-  York  1909.  net,  $4.00 

CLERK,  DUGALD.  The  Theory  of  the  Gas  Engine.  Third  Edition.  With 
additional  matter  edited  by  F.  F.  Idell.  Illustrated.  i6mo.  boards. 
180  pp.  (Van  Nostrand's  Science  Series,  No.  62.)  New  York, 
1903.  .50 

Dictionary.  Illustrated  Technical  Dictionary.  In  six  languages — English, 
German,  French,  Russian,  Italian  and  Spanish.  Edited  according  to  the 
Deinhardt  and  Schlomann  method  by  Alfred  Schlomann.  Vol.  IV.  In- 
ternal Combustion  Engines.  Compiled  by  Karl  Schikore.  1,000  illus- 
trations. Numerous  formulas.  i6mo.  cloth,  628  pp.  New  York, 
1908.  net,  $3.00 

DONKIN,  B.  Textbook  on  Gas  and  Oil  Engines.  Fourth  Edition,  revised  and 
enlarged.  165  illustrations.  8vo.  cloth.  568  pp.  London,  1905. 

net,  $7.50 

DOWSON,  J.,  and  LARTER,  A.  T.  Producer  Gas.  Second  Edition.  Illus- 
trated. 8vo.  cloth.  320  pp.  London,  1907.  net,  $3.00 

GARRATT,  H.  A.  Heat  Engines.  174  illustrations  and  folding  plates. 
5/4  x  7^2-  cloth.  345  pp.  London,  1912.  net,  $1.70 

GOLDINGHAM,  A.  H.  The  Gas  Engine  in  Principle  and  Practice.  Including 
comparison  of  the  two-cycle  and  four-cycle  types  of  Internal-Combus- 
tion Engines.  With  description  of  various  designs ;  together  with 
notes  on  suction  and  pressure  type  gas  producers,  crude  oil  vaporizers, 
etc.  105  illustrations.  6*4x914.  cloth.  195  pp.  New  York,  1912. 

net,  $1.50 

—  Design  and  Construction  of  Oil  Engines.  With  directions  for  erecting, 
testing,  installing,  running  and  repairing.  Third  Edition,  revised  and 
partly  rewritten.  Illustrated.  121110.  cloth.  280  pp.  N.  Y.,  1910.  $2.50 

GROVER,  F.  Modern  Gas  and  Oil  Engines.  An  exhaustive  treatise.  Fifth 
l:iiition.  Illustrated.  121110.  cloth.  372  pp.  London,  1909.  net,  $2.00 

GuLDNER,  H.    The  Design  and  Construction  of  Internal  Combustion  Engines. 

Translated   and   revised,   with   additions  on  American   Engines,  by   H. 

Diederichs.  A  handbook  for  designers  and  builders  of  gas  and  oil  engines. 

728  illustrations.     36  folding  plates.    4to.     cloth.     690  pp.     New  York, 

1910.  net,  $10.00 

CONTENTS:  VARIOUS  METHODS  OF  OPERATING  GAS  ENGINES  AND  THE  GAS  ENGINE 
CYCLES.     General    Considerations.      The   Various    Cycles    of   Operation.      Critical 


4  D.   I'AN  NOSTRAND  COMPANY'S  LIST  OF  BOOKS 

Examination  of  the  Various  Cyclic  Events.  THE  DESIGN  AND  CONSTRUCTION  OF 
INTERNAL  COMBUSTION  ENGINES.  Fundamental  Considerations.  Determination  of 
Principal  Dimensions.  General  Engine  Parts.  Special  Parts  for  Gas  and  Oil 
Engines.  Auxiliaries.  CONSTRUCTION,  ERECTION  AND  TESTS  OF  MODERN  INTERNAL 
COMBUSTION  ENGINES.  Stationary  Engines.  Portable  and  Self-Propelled  Engines. 
THE  GAS  ENGINE  FUELS  AND  COMBUSTION  IN  GAS  ENGINES.  Fuel  Gases.  Liquid 
Fuels.  Fuel  Mixtures.  Combustion  in  Gas  Engines.  APPENDIX.  Synopsis  of 
Thermodynamics.  Fundamental  Principles  of  Thermochemistry.  Some  Details 
from  Practice. 

HELDT,  P.   M.      The   Gasoline   Automobile ;   Its   Design   and   Construction. 

Volume   I. — The   Gasoline    Motor.      314   illustrations.      ^l/2  x  9.     cloth. 

.  500  pp.     New  York,  1911.  net,  $4.00 

HISCOX,  G.  D.  Gas,  Gasolene,  and  Oil  Engines.  Eighteenth  Edition,  entirely 
rewritten.  412  illustrations.  8vo.  cloth.  485  pp.  N.  Y.,  1910.  net,  $2.50 

HOGLE,  W.  M.  Internal  Combustion  Engines.  A  reference  book  for  de- 
signers, operators,  engineers  and  students.  106  illustrations.  121110. 
cloth.  250  pp.  New  York,  1909.  net,  $3.00 

HTJTTON,  F.  R.  The  Gas  Engine.  A  treatise  on  the  internal  combustion 
engine,  using  gas,  gasolene,  kerosene,  alcohol  or  other  hydrocarbon  as 
a  source  of  energy.  Third  Edition,  revised.  Illustrated.  8vo.  cloth. 
562  pp.  New  York,  1908.  $5.00 

JONES,  FORREST  R.  The  Gas  Engine.  142  illustrations.  8vo.  cloth.  447 
pp.  New  York,  1909.  Nezv  Edition.  $4.00 

—  Electric  Ignition  for  Combustion  Motors.    294  illustrations.     6}4  X9/^- 
cloth.    450  pp.    New  York,  1912.  net,  $4.00 

JTJNGE,  F.  E.  Gas  Power.  A  study  of  the  evolution  of  gas  power,  the 
design  and  construction  of  large  gas  engines  in  Europe,  the  application 
of  gas  power  to  various  industries,  and  the  rational  utilization  of  low 
grade  fuels.  Illustrated.  8vo.  cloth.  548  pp.  N.  Y.,  1908.  net,  $5.00 

KENNEDY,  RANKIN.  Modern  Engines  and  Power  Generators.  A  practical 
work  on  prime  movers  and  the  transmission  of  power.  Fully  illustrated. 
4to.  cloth.  London,  1907.  Six  volumes.  $15.00 

Single  volumes.  $3.00 

CONTENTS:  The  Prime  Mover:  Its  Sources  of  Energy,  Heat,  Electricity.  The 
Working  Substance  in  Heat  Engines :  Air,  Steam,  Water.  The  Engines — Turbines  : 
Air,  Water,  Steam,  Gas.  Reciprocating  Engines :  Single  Acting,  Double  Acting, 
Compound,  Triple,  and  Quadruple ;  Horizontal,  Vertical.  Engines,  Rotary.  Im- 
portant Parts  of  Engines :  Valves  and  Expansion  Gear,  Governors,  Condensers, 


ON  I'kOin'CllR  GAS  AND  GAS  AND  OIL  ENGINES.  5 

Pumps.  Air  and  Water.  Bearings  and  Rod  Knds.  Lubricators.  Generators — Steam 
Boilers  :  Cylindrical,  Tubular,  Flash.  Water  Tube,  Economizers,  Superheaters,  Feed 
Pumps,  Injectors,  Ejectors,  Water  Supply  and  Coolers,  Care  of  and  Mechanical 
Stokers.  Gas  Generators — Coal  Gas  and  Blast  Furnace  Gases :  Water  Gas,  Mond 
Gas,  Dovvson  Gas.  Oil  Fuels :  Heavy  Oils.  Light  Oils.  Spirit,  Gasoline,  Benzoline, 
Xaphtha,  and  Alcohol.  Electric  Engines — Dynamos  :  Batteries,  Generators,  Motors. 
Prime  Movers  Special,  as  made  by  Leading  Engineers — For  Mills,  Factories, 
Works,  etc.,  on  Land — Turbines,  Steam,  Water  and  Air.  Reciprocating,  Steam, 
Water,  and  Air.  For  Marine  Propulsion,  Steam,  Electric,  Water,  and  Air.  For 
Motor  Cars :  Steam,  Oil,  Electric.  For  Railways  and  Street  Railways.  Power 
Transmission  and  Transmitting  Gearing,  Belts,  Ropes,  Wheels,  Compressed  Air, 
Hydraulic  Pressure,  Electricity. 

LATTA.  NISBET.  Handbook  of  American  Gas  Engineering  Practice.  With 
numerous  diagrams  and  figures.  8vo.  cloth.  460  pp.  New  York, 
1907.  net,  $4.50 

CONTENTS :  Water  Gas  Manufacture  :  The  Generator.  The  Carburetter.  The 
Superheater.  Wash-Box  and  Tar.  Scrubbers.  Condensers.  Purifiers.  Ex- 
hausters. Station  Meters.  Holders.  Details  of  Works  Operation.  Gas  Dis- 
tributors: Naphthalene.  Mains.  Services.  Consumers'  Meters.  Pressure.  House 
Piping.  Appliances.  General  Technical  Data:  Properties  of  Gases.  Steam. 
Mathematical  Tables.  Conversion  Factors.  Pipe  and  Miscellaneous  Data. 

—  American  Producer  Gas  Practice  and  Industrial  Gas  Engineering.  A 
new  and  original  work.  246  illustrations.  Large  8vo.  cloth.  550  pp. 
New  York,  1910.  net,  $6.00 

CONTENTS :  Producer  Operation :  Cleaning  the  Gas.  Works  Details.  Producer 
Types :  Down  Draft  Producers.  Down  Draft  Apparatus.  The  Wood  System. 
The  Tait  System.  Operation  of  Tait  Producer.  Loomis-Pettibone  System. 
Westinghouse  Double  Zone.  Westinghouse  Bituminous  Gas  Producer.  The 
Morgan  Producer.  The  Herrick  Producer.  Smith  Lignite  Producer.  Lignite 
Suction  Producer.  Wood-Fuel  Suction  Producer.  Powder  Fuel  Producer.  Mar- 
conet  Powdered  Fuel  Producer.  Moving  Gases.  Solid  Fuels.  Physical  Proper- 
ties of  Gases.  Chemical  Properties  of  Gases.  Gas  Analysis.  Gas  Power.  Gas 
Engines.  Industrial  Gas  Applications.  Furnaces  and  Kilns.  Burning  Lime  and 
Cement.  Preheating  Air.  Doherty  Combustion  Economizer.  Combustion  in 
Furnaces.  Heat.  Temperature.  Radiation  and  Conduction.  Heat  Measurement : 
Pyrometry  and  Calorimetry.  Pipes,  Flues  and  Chimneys.  Materials :  Miscel- 
laneous Data.  Useful  Tables.  Oil  Fuel  Producer  Gas.  Glossary. 

LEVIN,  A.  M.  The  Modern  Gas  Engine  and  the  Gas  Producer.  181  illus- 
trations. 8vo.  cloth.  500  pp.  Xew  York,  1910.  net,  $4.00 

LEWES.  V.  B.  Liquid  and  Gaseous  Fuels  and  the  Part  They  Play  in  Modern 
Power  Production.  Illustrated.  8vo.  cloth.  334  pp.  (Van  Nostrand's 
Westminster  Series.)  New  York,  1907.  net,  $2.00 


f)          D.   I'AX  NQSTR4ND  COMPANY'S  LIST  OF  BOOKS 

LIECKFELD,  G.  Oil  Motors ;  Their  Development,  Construction  and  Manage- 
ment. A  handbook  for  engineers,  owners,  attendants  and  all  interested 
in  engines  using  liquid  fuel.  306  illustrations.  8vo.  cloth.  287  pp. 
London  and  Philadelphia,  1908.  $4.50 

LUCKE,  C.  E.  Gas  Engi'Ae  Design.  Second  edition.  145  illustrations.  8vo. 
cloth.  254  pp.  New  York,  1912.  net,  $3.00 

The  work  is  divided  into  three  parts.  The  first,  treating  of  power,  efficiency, 
and  economy,  gives  the  material  necessary  for  deciding  on  the  necessary  piston 
displacement  for  any  specified  output  for  any  kind  of  gas,  and  enables  the  designer 
to  approximately  predict  economy.  The  second  part  contains  the  data  and  method 
for  determining  the  stresses  in  the  parts  and  the  number  and  arrangement  of 
cylinders  necessary  for  balance  or  turning  effort  to  meet  the  specifications.  The 
last  is  entirely  concerned  with  the  dimensions  of  the  parts  to  resist  the  stresses, 
both  by  theoretic  analysis  and  by  empirical  formulae,  showing  between  what  limits 
every  principal  dimension  should  lie. 

MAEKS,  L.  S.,  and  WYER,  S.  S.  Gas  and  Oil  Engines  and  Gas  Producers. 
Illustrated.  8vo.  cloth.  137  pp.  Chicago,  1908.  $1.00 

MARSHALL,  W.  J.,  and  SANKEY,  H.  RIALL,  CAPT.  Gas  Engines. 
127  illustrations.  6x85^.  cloth.  293  pp.  New  York,  1911.  net,  $2.00 

CONTENTS:  Theory  of  the  Gas  Engine.  The  Otto  Cycle.  The  Two-Stroke 
Cycle.  Water-Cooling  of  the  Gas-Engine  Parts.  Ignition.  Operating  Gas 
Engines.  The  Arrangement  of  a  Gas  Engine  Installation.  The  Testing  of  Gas 
Engines.  Governing.  Gas  and  Gas  Producers. 

MATHOT,  R.  E.  The  Construction  and  Working  of  Internal  Combustion 
Engines.  Translated  from  the  French  by  W.  A.  Tookey.  A  practical 
treatise  on  methods  of  construction ;  with  calculations  for  the  use  of 
engineers,  manufacturers  and  users,  and  a  critical  study  of  present-day 
types.  Illustrated.  6>4x9//2-  cloth.  576pp.  London,  1910.  net,  $6.00 

—  Gas  Engines  and  Producer  Gas  Plants.  Translated  from  the  French 
by  W.  B.  Kaempffert.  Illustrated.  8vo.  cloth.  314  pp.  New  York, 
1906.  $2.50 

MEHRTENS,  A.  C.  Gas  Engine  Theory  and  Design.  Illustrated.  121110. 
cloth.  261  pp.  New  York,  1909.  $2.50 

MOSS,  S.  A.  Elements  of  Gas  Engine  Design.  Illustrated.  i6mo.  boards. 
J97  PP-  (Van  Nostrand's  Science  Series,  No.  121.)  N.  Y.,  1906.  .50 

O'CONNOR,  HENRY.  Petrol  Air-Gas.  A  practical  handbook  on  the  installa- 
tion and  working  of  air-gas  lighting  systems  for  country  houses.  Illus- 
trated. I2mo.  cloth.  75  pp.  London,  1909.  net,  .75 


ON  PRODUCER  GAS  AND  GAS  AND  OIL  ENGINES.           7 

PARSELL,  H.  V.  A.,  and  WEED,  A.  J.     Gas  Engine  Construction.      Third 

Edition,  revised  and  enlarged.  145  illustrations.  8vo.  cloth.  300  pp. 
New  York,  1906.  $2.50 

FOOLE,  CECIL  P.  The  Gas  Engine.  Illustrated.  8vo.  cloth.  103  pp.  New 
York,  1909.  net,  $1.00 

POPPLEWELL,  W.  C.     An  Elementary  Treatise  on  Heat  and  Heat  Engines. 

Illustrated.     I2mo.     cloth.     382  pp.     Manchester,  1897.  $2.50 

Questions  and  Answers  from  "The  Gas  Engine  Magazine."  Illustrated. 
i6mo.  cloth.  280  pp.  Cincinnati,  O.,  1907.  $1.00 

RATHBUN,  J.  B.  Gas  Engine  Troubles  and  Installation.  Illustrated. 
5^4x8.  cloth.  450  pp.  Chicago,  1911.  $1.00 

ROBERTS,  E.  W.  The  Gas  Engine  Handbook.  A  manual  of  useful  infor- 
mation for  the  designer  and  engineer.  Sixth  Edition,  revised  and  en- 
larged. Illustrated.  321110.  leather.  Cincinnati,  O.,  1903.  $1.50 

—  Gas  Engines  and  Their  Troubles.  With  additional  chapters  on  Design, 
Construction  and  Propulsion  of  Launches.  Illustrated.  I2mo.  cloth. 
151  pp.  New  York,  1905.  $1.50 

ROBSON,  P.  W.  Power  Gas  Producers ;  Their  Design  and  Application.  105 
illustrations.  8vo.  cloth.  254  pp.  London,  1908.  net,  $3.00 

RUSSELL,  T.  H.  Ignition,  Timing  and  Valve  Setting.  Illustrated. 
$%  x  8.  cloth.  240  pp.  Chicago,  1912.  $1.00 

SEXTON,  A.  H.  Producer  Gas.  A  sketch  of  the  properties,  manufacture  and 
uses  of  gaseous  fuels.  Illustrated.  8vo.  cloth.  228  pp.  Manchester, 
1905.  net,  $4.00 

SHARP,  ARCHIBALD.    Balancing  of  Engines ;  Steam,  Gas  and  Petrol.     An 

elementary  textbook,  using  principally  graphic  methods.  Illustrated. 
8vo.  cloth.  223  pp.  London,  1909.  net,  $1.75 

SIMMANCE,  J.  F.  Calorimetry  of  Producer  and  Illuminating  Gases.  With 
special  reference  to  future  legislation.  i6mo.  cloth.  30  pp.  London.  $1.00 

SMITH,  C.  ALFRED.  Suction  Gas  Plants.  55  illustrations.  I2mo.  cloth. 
205  pp.  London,  1909.  net,  $2.00 

SOREL,  ERNEST.  Carbureting  and  Combustion  in  Alcohol  Engines.  Trans- 
lated from  the  French  by  S.  M.  Woodward  and  J.  Preston.  Illustrated. 
i2mo.  cloth.  269  pp.  New  York,  1907.  $3.00 


8  D.   VAN  MOST  RAND  COMPANY'S  LIST  OF  BOOKS 

STODOLA,  A.  Steam  Turbines.  With  an  appendix  on  Gas  Turbines  and 
the  Future  of  Heat  Engines.  Authorized  translation  from  the  German 
by  Louis  C.  Lowenstein.  Second  Edition.  243  illustrations.  8vo. 
cloth.  488  pp.  New  York,  1906.  net,  $5.00 

STJPLEE,  H.  H.  The  Gas  Turbine.  Progress  in  the  design  and  construction 
of  turbines  operated  by  gases  of  combustion.  93  illustrations.  6  x  9. 
cloth.  270  pp.  Philadelphia,  1910.  net,  $3.00 

TOOKEY,  W.  A.  The  Gas  Engine  Manual.  A  practical  handbook  of  gas 
engine  construction  and  management.  Fully  illustrated.  8vo.  cloth. 
1 86  pp.  London,  1908.  $1.50 

WADSWORTH,  C.,  Jr.  Primary  Battery  Ignition.  A  simple,  practical 
pocket  guide  on  the  construction,  operation,  maintenance  and  testing 
of  primary  batteries  for  automobile,  motorboat  and  stationary  engine 
ignition  service.  Illustrated.  5  x  7.  boards.  78  pp.  New  York,  1912. 

net,  .50 

CONTENTS :  Definitions  and  Principles  of  Operation.  Electrolyte.  Electrode. 
Battery  Terminals.  Path  of  Current.  Potential.  Electromotive  Force.  Amal- 
gamation. Polarization.  Details  of  Construction.  Voltage  of  Cell.  Resistance, 
Electrical  Units.  Ohm's  Law.  Output  of  Batteries.  Setting  Up  and  Removing 
Batteries.  Open  and  Closed  Circuit  Batteries.  Dry  Cells.  Construction,  Out- 
put, Life  and  Capacity,  Care.  Battery  connections.  Battery  Connectors.  "Screw- 
top"  Cell  Connections.  "Combination"  Battery  Holders.  Testing.  Use  of  Am- 
meter. Testing  with  Buzzer.  Current  Required  to  Produce  Spark.  Various 
Battery  Troubles  and  Remedies. 

WIMPERIS,  H.  E.  The  Internal  Combustion  Engine.  Being  a  text- 
book on  gas,  oil  and  petrol  engines  for  the  use  of  students  and  engineers. 
114  illustrations.  8vo.  cloth.  339  pp.  London,  1908.  net,  $3.00 

WYER,  S.  S.  A  Treatise  on  Producer  Gas  and  Gas  Producers.  Second  Edi- 
tion. 8vo.  cloth.  310  pp.  New  York,  1907.  net,  $4.00 


on  Producer  Gas.     Illustrated.     121110.    cloth.    46  pp.     New 
York,  1906.  net,  $1.00 

Any    Book   in   this    List  will  be   sent    Postpaid  to    Any   Address  in  the 
World  on  Receipt  of  Price,  by 

D.    VAN    NOSTRAND    COMPANY 

Publishers    and   Booksellers 
25  PARK  PLACE  NEW  YORK 


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