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THE LIBRARY

THE UNIVERSITY
OF CALIFORNIA

GIFT OF

Dan Gutleban

COKE

A TREATISE ON THE

MANUFACTURE OF COKE AND OTHER
PREPARED FUELS

AND THE

SAVING OF BY-PRODUCTS

WITH SPECIAL REFERENCES TO THE METHODS AND OVENS BEST ADAPTED

TO THE PRODUCTION OF GOOD COKE FROM THE

VARIOUS AMERICAN COALS

JOHN FULTON, A. M., E. M.

Member of American Institute of Mining Engineers,

American Philosophical Society of

Philadelphia, Etc.

SCRANTON, PA.
INTERNATIONAL TEXTBOOK COMPANY

1906

Entered at Stationers' Hall, London

LOAN STACK .
GIFT

B- -17303

PREFACE TO SECOND EDITION

The first edition of Coke was issued by The Colliery Engineer
Company, of Scranton, Pennsylvania, in the year 1895 and was the
first treatise on this growing and important industry published in
the United States of North America. This edition was exhausted
over one year ago.

In the great progress of industrial manufacturers so manifest in
the United States, this interval of nine years since the appearance
of the first edition has retired some of the former methods in the
manufacture of coke, and introduced many new ones. This
advance in the progress of the industry has been induced by the
large increase in the demand for coke, arising from the expansion
in the use of steel and iron in architectural construction, as well as
in railroad supplies. In the manufacture of these materials, a pure
quality of coke fuel is an imperative necessity, and with the con-
sequent large demand on the best coking coal fields, it has become
necessary to extend coking operations outside these fields to regions
possessing coking coals of a lower grade, requiring, in most cases,
cleansing from the two principal impurities, slate and sulphur, by
the modern processes of crushing, classifying, and washing.

This necessary preparation or cleansing of coals for coking has
been an inviting field for mechanical experts in which to devise
machinery for this special purpose. It has also impressed the
necessity for studying the several conditions in which these foreign
matters are found in coals, so that proper machinery could be
devised to meet the several conditions necessary for eliminating
slate and sulphur.

This department of the coke industry has, during the past
decade, made commendable progress, especially in the preparation
of the coal for introduction into the washer, in disintegrating the
lumps of coal to certain sizes, and in the classification of the crushed
product as it is being conveyed into the washers. This important
auxiliary in the manufacture of coke enables the lower qualities
of coals to be utilized in the production of an acceptable
metallurgical fuel.

In addition to this coal-cleansing auxiliary in the coke industry,
an additional element has been introduced, meeting the conditions
of some coals low in bituminous matter — dry coals — in a fairly
satisfactory manner. These dry coals, low in fusing matter, could

iii

8S7

iv PREFACE TO SECOND EDITION

not be made to produce the best possible product in the usual open
beehive coke oven. To meet these exceptional conditions, the
retort coke oven has been introduced ; it is made in several types,
but the different types have one element in common — the retort or
closed-chamber principle, which affords a quick heat and permits the
utilization of the small content of volatile matter in these dry coals.

The large cost of these retort coke ovens, with the additional
expense of the apparatus for saving the by-products of tar and
ammoniacal liquor, has prevented their general introduction. In
addition to the large cost of installation, a retort-oven plant requires
a supply of coal for a long period to cover the investment in the
plant of ovens. Only certain localities can assure this supply of
coal, and unless the conditions of the manufacture will bear the
railroad freight charges necessary to continue the coal supply, when
it has to be obtained outside the immediate limits of the coke plant,
a retort-oven plant is impracticable. In situations where water
transportation can be secured, with its moderate freight rates, the
coal supply can usually be secured for long periods.

The use of the by-product tar in roofing and other applications,
with its anticipated use as a bonding element in the manufacture of
briquets, will enhance the value of this by-product.

In the first edition, the conditions were submitted that com-
pelled the writer, in 1875, then General Mining Engineer of the
Cambria Iron Company, to the study of the physical properties of
blast-furnace coke. At that time the blast furnaces of this com-
pany were supplied mainly by coke made from native coals in
Belgian ovens located at the works in Johnstown. This home-made
coke failed when the expansion of the steel industry required the
smelting of the Lake Superior iron ores in the production of Besse-
mer pig iron. The furnaces became hot above and cool below, and
the general manager, the late Hon. Daniel J. Morrell, requested an
investigation of the cause or causes of the inefficiency of this coke
fuel in the blast-furnace work.

Chemical analyses failed to disclose the trouble, as the native
coke was found to be much purer than the celebrated Connel.lsville.
This result came as a disagreeable surprise, causing a general search
of authorities on fuels for light on this matter, but without helpful
results. After a careful examination and study of the principal
blast-furnace fuels, anthracite coal, charcoal, Connellsville and
Johnstown cokes, it became evident that as chemical investigation
had failed to disclose the value of these fuels, it must be determined
by physical research.

In this investigation it became evident that two principal
requirements were demanded in blast-furnace fuel : hardness of body
and fully developed cellular structure; the first property to resist
the dissolution of the fuel, in its passage down the furnace, from the
attack of hot carbonic-acid gas, and the second to assure its rapid
combustion and calorific energy in the melting zone of the furnace.

PREFACE TO SECOND EDITION v

The hardness of the body of the coke was determined in the
usual way. The cellular space was determined by accurately cut-
ting inch cubes, weighing them dry and in water, and equating
conditions to determine the cell space in the body of the cokes.
The home-made coke was condemned from its lack of hardness of
body, while the Connellsville became the standard of blast-furnace
fuels from its hardness of body and full cell development.

The author believes that he was the first to originate this course
of investigation of blast-furnace fuels. Some criticism followed
the early results of these investigations, but the fact of priority in it
has not been questioned. During the meeting of the American
Institute of Mining Engineers, at Roanoke, Virginia, in June, 1883,
Mr. Fred G. Dewey, Washington, District of Columbia, a representa-
tive of the National Museum, in submitting a paper on the
"Porosity and Specific Gravity of Coke," said: "So far as I am
aware, the credit of the first systematic investigation of the physical
properties of coke belongs to Mr. John Fulton, Mining Engineer
of the Cambria Iron Company."

In a recent publication on the chemistry of coke, being the
"Grundlagen Der Koks-chemie" by Herr Oscar Simmersback,
translated and enlarged by W. Carrick Anderson, M. A., B. Sc., of
Glasgow, Scotland, it is submitted in the introduction: "Upon the
physical properties of coke, experiments were carried out first of all
by Americans. In 1875, John Fulton, then manager* of the
Cambria Iron Works Company, at Johnstown, Pennsylvania, dis-
cussed the variable action in the blast-furnace fuels containing the
same quantity of carbon. This variability he ascribed to the differ-
ence in their physical condition, anthracite, coke, and wood charcoal
being, as he showed, characteristicallv unlike in structure." (Iron,
1884, No. 602; Berg-and Huttenmannische Zeitung, 1844, p. 526.)

The author appreciates that in this wide field of research there
remains very much to be disclosed, but he trusts that this contribu-
tion may be helpful, especially in a practical way, to those interested
or engaged in this large and expanding industry — the manufacture
of coke.

In the preparation of this second edition, the author has neces-
sarily drawn from various sources, and due acknowledgment of
such help has been given in the text whenever it has been possible
to do so. He is laid under many obligations to the several publi-
cations of the United States Geological Survey, especially in the
valuable "Twenty-Second Annual Report, 1900-1901, Part" 3, Coal,
Oil, Cement;" and to the very comprehensive annual volume, "The
Mineral Statistics of the United States." Correspondence and
requests with this important department of the government have
always received prompt, accurate, and courteous responses.

*At the time noted above by Mr. Anderson, Mr. Fulton was the General
Mining Engineer of the Cambria Iron Company; subsequently he became
General Manager.

vi PREFACE TO SECOND EDITION

To Mr. James M. Swank, General Manager of the American Iron
and Steel Association at Philadelphia, he is indebted for valuable
statistics and helpfulness in the chapter on Briqueting.

Mr. J. V. Schaefer, formerly engineer of the Link-Belt Machinery
Company, of Chicago, but now of the firm of Roberts, Schaefer &
Co., Engineers, Chicago, Illinois, has contributed largely to chapter
III, on the preparation of coals for coking, especially on the treat-
ment in the Luhrig washer.

Messrs. Stein and Boericke, Metallurgical Engineers, Primos,
Delaware County, Pennsylvania, have contributed much matter on
the treatment of coals by crushing and washing, in preparation for
coking.

The Semet-Solvay Company, of Syracuse, New York, has con-
tributed drawings and statistics showing the size, product, and cost
of the Semet-Solvay retort coke oven.

Dr. F. Schniewind, of New York, has furnished many drawings
of the Otto-Hoffman and other retort coke ovens and statistics of
its work.

Mines and Minerals, a monthly journal, published by the Inter-
national Textbook Company, Scranton, Pennsylvania, has been
largely drawn upon for matter that has been used in several chapters
of this edition.

Extracts have also been made from several volumes of the trans-
actions of the American Institute of Mining Engineers.

Valuable help has been cheerfully afforded by the several invent-
ors of coke ovens, disintegrating machinery and washeries, as well
as from managers of coking establishments.

In the full chapter on "Briqueting in Europe and America,"
the reports of the United States consular service have been largely
utilized in presenting and illustrating this young industry.

Sincere thanks are returned to the many others who have so
kindly contributed to the matter in the pages of this second edition.

JOHN FULTON.

Johnstown, Pennsylvania, January 1, 1905.

PREFACE TO FIRST EDITION

The manufacture of coke in the United States of North America
began in a feeble way with four small establishments in the year
1850. During the 30 years following, the progress of the industry
was rather slow, but from 1880 to 1892 it made rapid advances,
showing in the latter year 261 establishments, using 42,002 coke
ovens and producing 12,010,829 tons of coke, valued at $23,536,141
at the ovens.

In the year 1869, coke outranked charcoal for use in blast fur-
naces; and in 1875, it surpassed anthracite coal. Since the latter
date, it may be said that we fully entered into the era of coke. It is
also evident that this coke fuel is destined to retain this leading
place of usefulness in metallurgical operations, and its increase is
destined to accompany the expansion of the iron and steel
industries.

In considering the present condition and future requirements of
the coke-making industry, with its paramount value in the manu-
facture of iron and steel, it appeared that a volume embracing the
principles and practice of the manufacture of coke would prove of
permanent value to those engaged in these correlated industries.
Its publication is regarded as the more needful at this time on
account of the efforts being made to introduce the modern types of
retort coke ovens, with their auxiliary apparatus for saving the chief
by-products — tar and sulphate of ammonia — from the gases
expelled in coking, and thus supplementing the profits in the coke
industry.

In the United States, the manufacture of coke has hitherto been
confined mainly to localities affording the best qualities of coking
coals. It required little skill to make excellent coke from such
good coals, but with the large expansion of the production of coke,
and the gradual exhaustion of the areas of the prime coking coals,
compelling the use of the secondary qualities of coking coals, a
thorough study of the merits of the several kinds of coke ovens
now being offered is regarded of the most important interest.

In this volume, the papers on the manufacture of coke that have
been published in The Colliery Engineer and Metal Miner, have
been recast and carefully revised. They give the several methods
of coking, with the results obtained, for the consideration of those
interested in this industry.

vii

viii PREFACE TO FIRST EDITION

The a'uthor feels that very much remains to be learned in this
department of industrial art, but trusts that this initial volume will
suggest matter that will lead to an accelerated advance in useful
knowledge along the several sections embraced in its pages.

The work has been undertaken with a feeling of the difficulty of
doing it the justice its importance deserves. But, in this respect,
the author trusts that some truth has been gleaned under the con-
ditions of the old adage that " necessity is the parent of invention."

In the 20 years' experience of the author, in his official position
of General Mining Engineer and General Manager of the Cambria
Iron Company, he has been required to study the manufacture of
coke in its elements of quality and cost. The extensive operations
• of this company in the different sections of the Appalachian coal
region, by several methods of coking, afforded desirable oppor-
tunities for investigation and for the comparison of results.

In the year 1875, the coke made at the works at Johnstown, in
Belgian coke ovens, failed to meet the furnace requirements. The
management requested an investigation of the cause or causes of the
inefficiency of this fuel in blast-furnace work. It appeared at first
to be an easy task to ascertain the nature of the defect or defects in
this coke. It was assumed that a chemical analysis would disclose
the whole matter, but, contrary to expectation, it did not ; it showed
the coke to be very pure, with much less ash than the Connellsville
coke, and with marked exemptness from other injurious elements.
The result compelled an expansion of the method of investigation,
as the chemical method alone would not reveal the cause.

A study to devise a method for the physical examination of the
coke was then entered upon, which, after many trials, resulted in
developing a plan that disclosed the main cause of the failure of this
coke for blast-furnace use — its want of the principal requirement,
hardness of body. From the softness of the body of this coke,
much of it was wasted in the upper section of the blast furnace by
dissolution in the bath of the ascending carbon-dioxide gas, thus
lowering the temperature at the zone of fusion, and disarranging the
regular operations of the workings of the furnace.

These early methods of testing the physical properties of coke
were very crude and open to criticism, but the urgency of neces-
sity, it is believed, has ultimately disclosed accurate methods of
determining the true value of coke for metallurgical uses, the
practical results in furnace work sustaining the reliability of these
determinations.

It has become evident in the manufacture of coke from the
secondary qualities of coking coals, that from the nature of the
requirements of quick and high-oven heat to secure the hardest-
bodied coke possible from such coal, the retort type of coke ovens
will have to be used.

It is confidently hoped that the plans and statements of the
actual work of these retort ovens, with and without apparatus for

PREFACE TO FIRST EDITION ix

the saving of by-products, will prove helpful in enabling the coke
manufacturer to make intelligent selection and application of the
special type of oven best adapted to assure the best coke from the
coal used in its manufacture.

Very much care has been given to the consideration of the best
modern methods in the preparation of coals for coking, especially
to the process of crushing and washing, for the elimination of slate
and pyrites.

In the preparation of this work, the author has necessarily drawn
from many sources, and due acknowledgment for such help will be
given when possible to do so. He is laid under many obligations to
Mr. Joseph D. Weeks, of Pittsburg, for extracts from his admirable
reports for statistics of the manufacture of coke, and for the results
of his recent visit to Europe. Mr. Walter M. Stein, metallurgist,
Philadelphia, agent for the Siebel retort coke oven, has kindly con-
tributed many papers on plans and work of coke ovens. Dr. F.
Schniewind, of Cleveland, Ohio, agent of Dr. C. Otto & Co., has
generously contributed very full information of the plan, cost, and
work of the Otto-Hoffman oven. Mr. W. B. Cogswell, general mana-
ger of the Solvay Process Company, of Syracuse, New York, has
kindly contributed plans and results of the working of the plant of
Semet-Solvay coke ovens at his place.

The author is also placed under renewed obligations to Sir Isaac
Lowthian Bell, of England, for plans of his Browney coke ovens,
and for his admirable method of testing the resistance of coke to the
action of carbon dioxide.

Mr. Henry Aitken, Falkirk, Scotland, has kindly contributed his
plans and studies in his methods of saving by-products from bee-
hive ovens.

The "Mineral Statistics of the United States," by Dr. David T.
Day, of Washington, District of Columbia, has afforded much help
in many ways; as have also the works of the Second Geological
Survey of Pennsylvania, by Prof. J. P. Lesley, State Geologist, and
his able assistants. Many valuable extracts have been made from
the several volumes of the transactions of the American Institute of
Mining Engineers.

Sincere thanks are returned to the many others who have so
kindly contributed to the matter in the pages of this volume.

CONTENTS

PREFACE TO SECOND EDITION.
PREFACE TO FIRST EDITION.

CHAPTER I

THE COAL FIELDS OF NORTH AMERICA .............................. 1

The Coal Periods ............................................ 4

Coal Fields of the United States ............................... 5

The Anthracite Fields ........................................ 5

Coal Fields of Canada ........................................ 16

Mexican Coal Fields ................ . ......................... 17

CHAPTER II

THE FORMATION AND CHEMICAL PROPERTIES OF COAL ................ 19

Composition of Coking Coals .................................. 24

Fusibility and Coking Properties ............................... 31

Impurities in Coal ............................ . ........... . . 38

CHAPTER III

PREPARATION OF COALS FOR THE MANUFACTURE OF COKE ............. 43

Crushing Coal ............................................... 46

Coal Washing ............................................. 56

Trough Washers ............................................. 57

Jigs ....................................................... 61

Brookwood, Ala., Washery .................................... 75

Coal-Washing Plant for Bituminous Coals at Coahuila, Mex ....... 79

Improvement of Coal Effected by Washing ..................... 97

Robinson Coal Washer Plant .................................. 99

The Liihrig Washer, Dowlais, Wales ....................... .... 101

The Liihrig Washer, Nelsonville, Ohio .......................... 108

The Liihrig Washery at Punxsutawney, Pa ...................... 110

The Stewart Coal Washer ..................................... 113

Stein & Boericke Washer ..................................... 122

Baum Washer. . . ............................................ 123

A Baum Washing Plant at Gladbeck, Westphalia ................ 128

Washer for Fine Coal. . .129

xii CONTENTS

CHAPTER IV page

HISTORY AND DEVELOPMENT OF THE COKE INDUSTRY 131

Statistics Showing Development of Coke Industry 133

Coal Required to Produce 1 Ton of Coke 137

CHAPTER V

MANUFACTURE OF COKE 145

Methods of Coking Coal 145

Coking Coal in Heaps or Mounds 145

To Determine Loss of Carbon in Process of Coking 147

Beehive Coke Oven 148

The Coking Process : 157

Old Welsh Oven 164

The Thomas Oven 164

Browney Coke Plant 167

Use of Waste Gases for Steaming at Pratt Mines, Ala 169

The Ramsay Patent Beehive Coke Oven 173

Daube's Economic Down-Draft Coke Oven 177

Improved Heminway Process 178

Newton-Chambers System 186

The Smith Coke Drawer 187

The Hebb Coke Drawer 188

Silica Brick 191

Coking Experiments and Results 192

Effects in Physical Properties of Coke Produced by Crushing the

Coal 195

CHAPTER VI

RETORT AND BY-PRODUCT-SAVING COKE OVENS 200

Introduction 200

The Belgian Oven 206

The Coppe'e Coke Oven 208

The Appolt Coke Oven 212

Comparison of Oven Types 214

Modification of Appolt Coke Ovens at Blanzy. . 215

Simon-Carves Ovens 219

G. Seibel's Retort Coke Oven 223

Manufacture of Sulphate of Ammonia 232

Otto-Hoffman Retort Coke Oven 235

Otto-Hoffman Ovens and By-Product Apparatus of the Pittsburg

Gas and Coke Co 248

The Schniewind Oven 252

Utilization of the By-Products of the Coke Industry 256

Festner-Hoffman Coke Oven 7* 260

Semet-Solvay Coke Oven 263

West Virginia Coals in Semet-Solvay Ovens , 268

CONTENTS xiii

Page

Semet-Solvay Plant at Dunbar, Pa 273

Connellsville Coke from Semet-Solvay Ovens 277

The Rothberg By-Product Coke Oven 290

The A. Hiissner Coke Oven 291

The Bernard Coke Oven 294

The Brunck Coke Oven 298

The Bauer By-Product Coke Oven 302

The Lowe Coke Oven 306

The New Lowe Coke Oven and Gas-Making System 306

Beehive By-Product Oven 311

The Manufacture of Coke From Compressed Fuel . 312

Coke Pusher 318

Coal-Distillation Plant at the Matthias Stinnes Mines in Carnap,

Germany . 320

CHAPTER VII

PHYSICAL PROPERTIES OF CHARCOAL, ANTHRACITE, AND COKE, AND A

COMPARISON OF BEEHIVE AND BY-PRODUCT COKE 326

Comparison of Beehive and By-Product Coking 335

Effects of the Several Types of Coke Ovens on the Physical Prop-
erties of Their Coke Products 348

CHAPTER VIII

THE LABORATORY METHODS OF DETERMINING THE RELATIVE CALOR-
IFIC VALUES OF METALLURGICAL FUELS 353

CHAPTER IX

THE LOCATION OF PLANTS FOR THE MANUFACTURE OF COKE 361

The Morrell Plant 364

No. 3 Plant, H. C. Frick Coke Co 365

Oliver Plant 366

Coke Making for Profit 369

American Coke Company's Plant 375

The Hostetter Connellsville Coke Company's Works 375

The Joseph Wharton Coke Plant 376

Retort Oven Plants 379

Production of Illuminating Gas From Coke Ovens 381

The Everett Coke Oven Gas Plant 384

CHAPTER X

GENERAL CONCLUSIONS ON THE WORK, COST, AND PRODUCTS OF THE

SEVERAL TYPES OF COKE OVENS 392

Comparison of Different Types of Ovens 397

Advisability of Saving By-Products 401

xiv CONTENTS

CHAPTER XI page

THE FUEL BRIQUETING INDUSTRY 406

Composition of Briquets 409

Methods and Cost of Manufacturing Briquets 417

Briqueting in Austria-Hungary 417

Briqueting in Belgium 419

Briqueting in France 422

Briqueting in Germany ....'. 433

Peat Manufacture 439

Briqueting in Norway and Sweden 445

Briqueting in Great Britain 448

Briqueting in Canada 453

Briqueting in the United States 462

TREATISE ON COKE

CHAPTER I

THE COAL FIELDS OF NORTH AMERICA

Importance of Coal. — Geology, like history, has its special and
important epochs. The coal-making periods are the most remark-
able in the geology of our planet, for, during these periods, the
great deposits of mineral fuel were stored up, anticipating and pro-
viding for the wants of the coming man, in the order of his com-
fort, civilization, and poWer.

Among all the valuable gifts the Creator has bestowed upon
man, coal is the most essential to his well being and progress. It
is true that man could exist, under the beneficence of the sun's
warmth and the fuel from the vegetation of the field and forest;
but it is clearly evident that to attain the best conditions of civili-
zation and power, he must have the fuel supply, the stored up and
crystallized sunlight, of the old-time coal-making periods.

The value of this coal endowment has now become a standard
by which the nations of the world are classified as to their present
power and future progress. Recent experience has emphasized
the vital importance of this coal supply.

From our present knowledge of the extent of the coal fields,
the following graphic comparison will exhibit the relative ranks
of the nations of the world in their possessions of coal.

This graphic comparison of coal areas shows that the United
States of America inherits a wealth of coal, so far as developed,
equal to that possessed by all the other countries of the world.

Future explorations will doubtless increase the area of coal in
the United States, British America, and in the less-developed
countries of foreign lands. The production represented by the
square for "Other Countries" will in all probability be greatly
increased in the near future as the deposits of China and Japan
are opened up. The United States need be in no fear of losing
first place, however, at least for a long time. In 1899 we wrested
first place from Great Britain and our production is steadily
increasing and widening the gap.

TREATISE ON COKE

COAL FIELDS OF THE WORLD— 1902

United States of America

344,440 square miles

British America • • 60,000 square miles

Great Britain !• 12,000 square miles

Spain J| 4,000 square miles

France _^_ 2,000 square miles

Germany g_ 1,800 square miles

Belgium m 600 square miles

Other Countries .

— 110,000 square miles

TREATISE ON COKE

The following statistical diagram shows the relative product of
coal by the several nations of the world:

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TREATISE ON COKE

*ofc K;

Peat— Turf

The Coal Periods. — The columnar section shows the places of
the coal among the rocks. While there were three periods of
greatest deposit, the evidence in the remains of plants from the
Laurentian to the Tertiary shows that plant life, in greater or

less degree of development, ac-
companied all the sedimentary
deposits.

The remains of this vegetable
growth are found in the Lauren-
tian in the mineral graphite,
which is usually associated with
folded and flexed strata.

In the eastern part of the
United States and in the lower
coal measures, which are also
greatly compressed and flexed,
anthracite coal is the product of
this old-age flora. Westward, in
the Carboniferous period, under
modified conditions of rock flex-
ure, the rich bituminous coals are
Comanche Group the crystallized remains of the
luxuriant flora of this epoch.
Farther westward, in the Jurassic,
Cretaceous, and Tertiary periods,
bituminous and lignite coals are
found, as the results of the recur-
rences of the periods of the coal-
making flora.

The more recent vegetable
deposits found in the peat or turf
bogs afford interesting and sug-
gestive examples of the genesis of
coal, although the flora exhibits
newer forms and conditions from
the old-time periods of the coal-
making plants.

An example of the mode of
bog or turf deposit, as it is being
accumulated at present, is seen
on the line of the N. N. & W. Rail-
way, in Newfoundland. These
deposits occur at intervals along
the line of this railway and con-
sist of a series of bogs in which
a growth of moss and other
swamp plants is accumulating.
Under the cold and foggy climate

Coal Lignites

Laramie Series
Coal

Dakota Group

Coal

Permian

Coal Measures

Upper Silurian

Lower Silurian

Primordial

Huronian

Laurentian

SECTION SHOWING THE PLACES OP COAL IN
THE ROCKS — LE CONTE

TREATISE ON COKE 5

and with frequent drizzling rains, the vegetable mass is being
altered into black bog in the bottom and brown bog above this
lowest strata, with the moss and heather on the surface. These
deposits are 4 to 6 feet deep, and exhibit all the processes of
growth, with the graduations from brown bog down to the dense
black bog from which turf is made. It only requires a further
series of conditions to compress and crystallize all this vegetable
matter into true coal.

COAL FIELDS OF THE UNITED STATES

The accompanying geological map of the United States shows
the approximate areas and localities, as far as determined, of the
Carboniferous, Triassic, Cretaceous, and Tertiary coals, each period
being distinguished by appropriate cross-sectioning.

As this map is designed for practical use, it is not considered
expedient to adopt, at this time, the rather intricate classification
of the great coal fields used by the United States Geological Sur-
vey in some of its latest publications.

The Appalachian field is uniform in the quality of its coal, from
New York state to Alabama. It does not .appear necessary to
give it a double name, Northern and Southern — the same is
true of the Western fields. These are distinctions without any
economic differences.

The table of outputs of coal in states and territories has also
been grouped under the clear classification of the old system.

These coal fields of the United States are usually classified
under eight main divisions in the following order:

I. The Anthracite Coal Fields. — These embrace in the aggre-
gate about 1,010 square miles. The extreme eastern anthracite
field, lying mainly in Rhode Island, with its north end resting in
Massachusetts, contains about 500 square miles of coal measures.
It affords peculiar varieties of anthracite and graphitic coals, but
contributes only a small output to local markets.

In Northeastern Pennsylvania, the triple anthracite coal fields
cover an aggregate area of 485 square miles. These three regions —
the Schuylkill, the Lehigh, and the Wyoming — with their small
annexes, contain beds of pure, glassy, anthracite coal, with thick-
ness of seams from 3 feet to 60 feet. The total output of these
fields during the year 1901 was 67,471,667 net tons, valued at
$112,504,020. The small anthracite field in Sullivan County,
Pennsylvania, with detached patches of anthracite in Maryland,
West Virginia, Colorado, and New Mexico, cover an aggregate area
of 25 square miles.

All the above coals • are found in the regular Carboniferous
measures. Anthracite coal is heavily compressed natural coke.

TREATISE ON COKE

The elementary composition of the coals in the anthracite fields
will be readily seen from the average proximate analysis of each
section given below:

ANALYSES OF ANTHRACITE

Moisture
Per Cent.

Volatile
Matter
Per Cent.

Fixed
Carbon
Per Cent.

Ash
Per Cent.

Sulphur
Per Cent.

Rhode Island
Massachusetts

8.36

2.05

6.09
4.99

73.23
76.96

11.68
15.44

.64
.56

Pennsylvania

2.98

3.38

87.13

5.86

.65

Colorado

3.42

8.76

78.87

8.30

.65

II. The Atlantic Coast Triassic Coal Fields. — These detached
coal fields are found midway between the Blue Ridge Mountains
and the Atlantic Ocean. They consist of the Richmond and
Farmville basins in Virginia, and the Dan River and Deep River
basins in North Carolina. The aggregate area of these coal fields
is 660 square miles.

The coal in the Richmond basin is bituminous, and, when prop-
erly treated, makes a medium quality of coke. The natural coke or
carbonite of this basin is a peculiar product, as some sections of the
coal beds have been coked by the intrusion of diabase dikes, which
follow the floor or roof of the coal beds, producing a light cellular coke.

The coal beds in the Farmville field are of moderate thickness
and much disturbed by flexures and faults.

The Deep River and Dan River fields are found under similar
conditions to the Farmville. The Dan River region is regarded
more hopefully than the others.

ANALYSES OF TRIASSIC COALS AND COKES

Locality

Moisture
Per Cent.

Volatile
Matter
Per Cent.

Fixed
Carbon
Per Cent.

Ash
Per Cent.

Sulphur
Per Cent.

Remarks

Richmond basin 1
north side . . . . /

24.57

62.39

13.04

Averages

Richmond basin, j
south side. . . . /

34.25

62.97

3.24

Averages

Natural Coke. . . .

1.66

18.35

67.13

12.86

4.70

Natural Coke. . . .

9.98

80.30

9.72

Farmville

1.43

28.28

53.60

11.81

4.67

Averages

Dan River

.36

17.99

55.47

26.16

5.56

Dan River. ...

13.50

76.56

12.00

Deep River . . . . j
Cumnock Mine . /

1.216

32.914

57.36

6.58

1.93

f Main
I bench

III. The Appalachian Coal Field. — The Appalachian coal field is
the largest and most liberally endowed coal field in the world. It

TREATISE ON COKE

lies along the western side of the Appalachian mountains, and has
a general trend southwestwards. The northern end, with its ter-
minal fingers and outlying coal fields, rests in Northwestern Penn-
sylvania, nearly touching the New York state line. The southern
end rests in the state of Alabama. It has a length somewhat over
800 miles, with a width of 30 to 180 miles, and covers, in its broad
southwestward course, portions of the states of Pennsylvania, Ohio,
Maryland, Virginia, West Virginia, Kentucky, Tennessee, and
Alabama. The general trend of its eastern border approximates
to a conformity with the shore line of the Atlantic Ocean. The
coal measures belong to the Carboniferous proper and vary in
aggregate thickness from a few hundred feet to 3,000 or 4,000 feet.

There are two groups of coal beds in this field — the lower and
upper — which are associated with the lower and upper barren
measures. The Pottsville, or Serai, conglomerate is the base of
these coal measures. The lower coal beds embrace a thickness of
280 feet, more or less. The lower barren measures have a thick-
ness of 600 feet. The upper productive coal measures have a
thickness of 360 feet, while the upper barren, or capping, measures
are, at some localities, 1,100 feet thick. This great coal field,
which includes an area of 59,370 square miles, affords the largest
areas producing coal for the manufacture of coke.

The general structure of the anthracite and Appalachian coal
fields consists in a series of rock waves and flexures, beginning
in billows near the seaboard, moderating to waves in the middle
Appalachians, and calming to mild ripples on the western flank of
this longitudinal belt of some 300 miles in width.

West Virginia is credited with having the maximum depth
of coal measures. The coal beds vary from a few inches to 10 feet or
more in thickness and the percentage of coal to the associated rocks
and shales is usually estimated as 1 foot of coal to 50 feet of slate
and rock measures.

It is impossible, in a brief table, to give all the qualities of coals
embraced in this large territory, but it is believed that the following
tabulated analyses will give the general averages :

ANALYSES OF APPALACHIAN BITUMINOUS COALS

Moisture
Per Cent.

Volatile
Matter
Per Cent.

Fixed
Carbon
Per Cent.

Ash
Per Cent.

Sulphur
Per Cent.

Pennsylvania — East . .

1.73

23.89

67.03

6 69

Pennsylvania — West
Ohio

1.70
1 58

39.15
41 86

46.66
51 44

10.52
5 12

1.97
2 64

West Virginia — East

1 52

19 81

72 71

5 20

West Virginia — West. .

1 52

37 86

53 37

6 03

1 22

Kentucky

1 80

33 00

60 10

5 10

Tennessee
Alabama . .

1.50
1 65

32.51

32 48

59.33
60 15

5.82
4 82

.84
90

TREATISE ON COKE

IV. The Northern Coal Field. — The Michigan coal field, in the
middle of the state, covers an area of 7,500 square miles. This coal
basin lies in a rather flat country, surrounded by higher land.
These coal measures belong to the true Carboniferous period. The
coal seams are somewhat irregular in character and continuity.
During recent years, considerable mining has been entered upon.
The upper coal beds afford coking coal, the lower beds of coal
are non-coking.

ANALYSES OF MICHIGAN COALS

(From Alfred C. Lane)

•

Moisture
Per Cent.

Volatile
Matter
Per Cent.

Fixed
Carbon
Per Cent.

Ash
Per Cent.

Sulphur
Per Cent.

Pere Marquette, No. 1 Saginaw. . . .
Jackson New Hope mine

10.15
5.58

33.14

46.73

53.95

45.28

2.76
2.41

1.10
2.83

Saginaw Co Verne

5.82

39.79

45.15

9.24

3.83

V. The Central Coal Field.— This coal field of 46,000 square
miles lies in the states of Illinois, Indiana, and Western Kentucky.
It contains the three general varieties of bituminous, block, and
cannel coals. The main portions of the coals of this field are 'rich in
bituminous matter. The block coal of Indiana is a peculiar fuel;
in coking, its volatile matters are expelled, leaving the normal
structure of the coal intact, and in this condition it is simply a
charred coal.

ANALYSES OF CENTRAL FIELD COALS

Moisture
Per Cent.

Volatile
Matter
Per Cent.

Fixed
Carbon
Per Cent.

Ash
Per Cent.

Sulphur
Per Cent.

Block

2.10

39.05

55.20

2.90

.75

Indiana | Bituminous

2.98

40.98

50.70

3.46

1.88

Illinois, Jackson County . . .
Kentucky {^uminous....

2.08
4.48
1.46

37.10
32.22
45 '.35

52.17
54.03
45.80

7.02
7.90
6.63

1.63
1.37
.76

During recent years, the Illinois coals have been mined largely,
and under careful treatment have appreciated in market value.
Efforts are now being made to coke some of the coals in this field,
which, with the improved machinery for crushing, classifying, and
washing, afford indications of moderate success. So far, however,
the efforts at coking the large bed of coal in Southern Illinois have
not met the expectation of the parties in Chicago that have made
a series of experiments testing the coking properties of these coals.

VI. Rocky Mountain Coal Fields. — The Rocky Mountain coal
regions cover portions of the Dakotas, Montana, Idaho, Wyoming,

TREATISE ON COKE

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Character of Coal

Coking
Coking
Bituminous
Semibituminous
Lignite
Anthracite

Lignite
Bituminous

Lignite
Bituminous
Anthracite

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TREATISE ON COKE

Utah, Colorado, and New Mexico. The coal fields in this territory
embrace the deposits on the flanks of the Rocky Mountains, the
main areas of coal, developed at this time, being found on the east-
ern side of these mountains.

The qualities of these coals are quite varied, including the Permo-
Carboniferous, the Jura-Trias, with the Laramie, the Cretaceous, and
the Tertiary. Some of these coals make good coke, but many of
them will not fuse in a coke oven. Several of the beds are quite
thick, and afford valuable fuel for generating steam, and for metal-
lurgical, manufacturing, and domestic uses.

Within the past decade, the United States government officials
have investigated and thrown much favorable light on these fields,
and these investigations, together with private enterprise, have
disclosed the increasing value of these great coal deposits.

The following statement, from the Twenty-second Annual
Report of the United States Geological Survey, will exhibit the
progress in coal mining and coke making in this extensive coal
region during the year 1901:

State

Coal Produced
Net Tons

Coke Made
Net Tons

Dakota. . . .

Montana

1.396,081

57,001

Idaho

^Wyoming

4 485 374

Utah

1 322,614

Colorado •.

5,700,015

671,303

New Mexico. . .

1,546,652

41,643

The coal measures in these fields cover an area of 100,110 square
miles as known at the present time, but future explorations and
government surveys will probably increase the area.

VII. The Western Coal Field. — The western coal field occupies
the southern portion of the state of Iowa, the southeastern corner
of Nebraska, the northwestern section of Missouri, the eastern side
of Kansas, passing through the eastern portion of the Indian Terri-
tory and resting in a great prong in the middle of the state of
Arkansas. It occupies the interior plain of the continent, and
has an area of 99,800 square miles of coal measures.

Extensive mining operations are carried on in the states of Iowa,
Missouri, and Kansas, and in the Indian Territory where recent
explorations have developed large beds of coal fairly well adapted
to the manufacture of coke In the states of Missouri and Kansas
a few coking plants are in operation, but the output is small. In
the Indian Territory, several coke plants are in successful operation,
the coke being marketed mainly in Mexico.

TREATISE ON COKE
ANALYSES OF WESTERN COALS

Moisture
Per Cent.

Volatile
Matter
Per Cent.

Fixed
Carbon
Per Cent.

Ash
Per Cent.

Sulphur
Per Cent.

Iowa ....

3.00

6.50

3.25

1.05
1.79
1.02
1.05

38.25
37.71

40.96
19.04
40.20
10.49
14.65

48.50

42.17

43.98
71.73
51.79
76.12
76.11

7.50
10.56

10.71
7.53
4.88
9.96
6.63

2.75

3.06

1.10
.65
1.34
2.41
1.56

Missouri

Nebraska
Kansas

Indian Territory{^t:;;
f East . .

Arkansas{West

The Texas coal field belongs, by geographical position, to the
Western field. Prof. E. T. Dumble, formerly State Geologist, in
regard to these lignites, states: "It should, however, be plainly
understood in the beginning, that the brown coals of Texas will
be found to differ very widely in quality, and it will require
analysis of each deposit to tell with certainty for what purpose it
is best adapted."

ANALYSES OF BROWN COALS OF TEXAS

Moisture
Per Cent.

Volatile
Matter
Per Cent.

Fixed
Carbon
Per Cent.

Ash
Per Cent.

Sulphur
Per Cent.

Stevens .

10 00

5 81

48 46

4 20

1 53

Eagle Pass .

5.27

37.48

44 46

10 22

2 57

Laredo

2.00

50.05

39.10

7 35

1 50

Bowie County

10.32

76.35

11.53

1.45

.35

VIII. The Pacific Coast Coal Fields.— The Pacific Coast coal
fields embrace a number of detached fields in the states of Washing-
ton, Oregon, California, and Alaska. These coals are nearly all of
the Tertiary age, and of the general character of lignites. The
fields are of limited extent and widely separated. Their products
of coal and coke during the year 1901 were as follows:

State

Coal
Net Tons

Coke
Net Tons

Washington

2 578 217

49,197

Oregon

69011

California and Alaska

151,709

The geological survey of these fields is not yet complete. It is
estimated, from what is known, that the aggregate area of these
coal fields is about 30,000 square miles. The coal is mainly of the
Eocene age, ranging from lignite to coking coal.

TREATISE ON COKE

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TREATISE ON COKE

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Output of Co
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Net Tons

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TREATISE ON COKE

In Western Washington, some seams of bituminous coal have
recently been found which are reported as well adapted for the
manufacture of coke; and, also, in Eastern Washington coking coals
have been developed.

In addition to these fusing or coking coals found in this field,
the chief varieties of coals are valuable for industrial and domestic
purposes.

ANALYSES OF PACIFIC COAST COALS

Moisture
Per Cent.

Volatile
Matter
Per Cent.

Fixed
Carbon
Per Cent.

Ash
Per Cent.

Sulphur
Per Cent.

Washington <
Oregon j

2.36
1.74
20.00

41.91
30.70
32.50

48.65

58.30
41.98

7.08
9.26
5.34

California I

1.53
15.50

38.33
40.00

44.94
29.50

10.71
15.00

4.49

Alaska. . . .

18.08
2.57

39.30
55 44

35.61
29 75

7.01
12 24

Evidently there is a large area of the Washington coals that,
with careful preparation in crushing and washing, will make excel-
lent coke.

COAL FIELDS OF CANADA

In the Dominion of Canada, the coal deposits have been classed
in three sections:

I. The Nova Scotia and New Brunswick Fields. — These lie in
the Bay of Fundy, and have a desirable location for marketing their
coal on the Atlantic seaboard. The coal is similar in quality to the
coal of the eastern Appalachian field. The coal measures are 13,000
feet thick, and the aggregate area of the two fields is reported to be
18,000 square miles.

The coal belongs to the Carboniferous period, and is used for
coking, for iron manufacture, and for all industrial and domestic
purposes.

AVERAGE ANALYSES OF NOVA SCOTIA AND NEW BRUNSWICK COALS

Moisture
Per Cent.

Volatile
Matter
Per Cent.

Fixed
Carbon
Per Cent.

Ash
Per Cent.

Sulphur
Per Cent.

Pictoti

1.20
1.30
1.10
1.15
1.10

.50

28.43

37.50
29.10
25.61
25.83
57.10

56.98
56.00
56.60
60.73
67.57
42.40

13.39
5.20
13.20
12.51
5.50
.27

Joggins

Springhill
Nova Scotia

Cape Breton

Albertite

TREATISE ON COKE

II. British Columbia and Vancouver's Island Field. — The coal
measures in this section belong to the Cretaceous and Tertiary for-
mations. The coal beds are large and the quality is mainly of the
better class of such coals. The amount of pressure appears to be
the important factor in determining the physical properties of these
coals, and consequently of their value.

ANALYSES OF BRITISH COLUMBIA AND VANCOUVER COALS

Moisture
Per Cent.

Volatile
Matter
Per Cent.

Fixed
Carbon
Per Cent.

Ash
Per Cent.

Sulphur
Per Cent.

a Non-coking

15 75

35 40

41 45

7.40

b Non-coking

8 60

35.51

46.84

9.05

c Good coking

36 . 065

61.29

2.645

McKay No 14

4.. 01

40.07

51.82

4.10

Nanainio ...

1.70

38.10

48.48

11.72

III. Eastern Rocky Mountain and Great Plains Field. — In the

great plains east of the Rocky Mountains, and in the eastern flank-
ing ridges, the coal occurs in the Cretaceous formation, including
the Laramie. This field is simply the extension, northwards, of the
lignite and brown coal measures of the Rocky Mountain series of the
United States. Some of these coals can be used for the manufac-
ture of coke, but the larger proportion goes to other uses.

ANALYSES OF ROCKY MOUNTAIN AND GREAT PLAINS COALS

Moisture
Per Cent.

Volatile
Matter
Per Cent.

Fixed
Carbon
Per Cent.

Ash
Per Cent.

Sulphur
Per Cent.

a Non-coking. . . . ...

20 54

33 26

41 15

5 05

b Non-coking

10.35

34.40

39.61

15 64

c Non-coking
d Good coking

6.50
4.41

38.04
40.32

47.91
48.27

7.55
7.00

e Western anthracite

.71

10.79

80.93

7.57

MEXICAN COAL FIELDS

The Mexican coals are evidently found in the Cretaceous or Ter-
tiary formations, probably in the former. They appear to be
related in part to the Texas coals.

The Coahuila Coal Company, near Sabinas, on the Mexican
International Railroad, mine coal and make a fair quality of coke
from washed Alamo coal. The analvses are as follows:

TREATISE ON COKE

Moisture
Per Cent.

Volatile
Matter
Per Cent.

Fixed
Carbon
Per Cent.

Ash
Per Cent.

Sulphur
Per Cent.

Coal .

20.35

67.64

12.01

Coke

1 35

1.35

83.80

14.85

1.08

The coke is used mainly in smelting establishments, and com-
mands a ready sale. It is a fairly good coke, approximating in its
physical properties the Tioga coke of Pennsylvania. The coal from
which it is made requires careful and intelligent work in preparing
it for the coke oven.

CHAPTER II

THE FORMATION AND CHEMICAL PROPERTIES OF COAL

Formation of Coal. — The genesis of coal has now been clearly
shown to have been in the swamp flora of the old-time periods of
coal making, and the vegetable origin of coal is therefore no longer
questioned. This conclusion has been reached from the evidences
of the remains of plants of these Carboniferous periods in imme-
diate connection with the coal beds; by the physical structure of
the coal, disclosing the anatomy of the several . families of plants
from which it was made; and from chemical analyses tracing its
derivation from vegetable matter.

Coal, therefore, was made from vegetable and woody matter,
which grew luxuriantly in broad and extended marshes in the old-
age times, when the Appalachian sea covered most of the continent
of North America. This vegetable matter, in its decay and fall,
was entombed in the waters of these swamps, which kept it from
the atmosphere, and thus preserved it from oxidation or waste.

It is also evident that 'the more thoroughly this vegetable
matter was submerged, the more .perfectly the resulting coal was
bituminized. This immersion in water contributed a very impor-
tant element in the formation of the more highly bituminous and
coking coals.

The deposit of carbonaceous matter was followed by a covering
of slates, shales, sandstones, or limestone deposits, which afforded
different degrees of pressure on the entombed vegetable matter,
and assisted in the subsequent crystallization of the coal.

The flora of the coal-making periods consisted mainly of the
large families of tree ferns, Sigillaria, Calamites, and their allies —
soft, rapid-growing plants, with jointed stems and broad spear-
shaped leaves, which fell in frequent showers into the waters of
these marshes. These, with the mosses, ground ferns, and other
plants, composed the vegetable mass that made the coal.

The atmosphere of the coal -flora periods was in large part com-
posed of carbon dioxide, which contributed largely to the heat,
and furnished plant food for the luxuriant growth of the flora.

But complementary to all these conditions of climate, rapid
vegetable growth, and swamp lagoons to preserve it for coal making,
great movements in the earth crust were of prime necessity in

2 19

20 TREATISE ON COKE

affording definite time for the accumulation of vegetable matter to
make coal beds of useful thickness and to entomb them for the
use of the coming age of man.

The broad geological law has been fully established, that all
continents have been formed beneath the sea and then emerged
from it. Not only this, but also from the way the several sedimen-
tary formations rest upon each other, it is evident that the land
has been alternately emerged and submerged many times in the
process of its formation. These movements of the submergence
and emergence, during the formation of the coal measures, are in
entire harmony with the laws governing the formation of all the
sedimentary deposits.

It will also be readily understood that in the coal-making
periods, under varied conditions and extended time, a variety of
coals have been made, with different degrees of purity, and with
varied ratios of fixed to volatile matters. These changes have
also been influenced by the subsequent movements in flexing the
strata, producing the debituminization of the coal in greater or
less degrees. In the greatly flexed and folded regions of the coal
fields, local causes have contributed to carry the change still
further, producing anthracite coal from the evolved heat in these
movements. Where this metamorphosis has been carried still
further, the ultimate is produced in graphite or black lead.

It is well known that all vegetable tissue contains some incom-
bustible matter, which is designated as "ash "in coal. It ranges
from 1 or 2 per cent, to 5, 10, or more per cent, in the usual varieties
of coals, t When coal contains more than 5 per cent, of ash, it is
evidence of the deposit of mud from other sources than the vege-
table matter making the coal. This additional impurity has come
into coal from sediment in the waters of the marshes and from the
fine muds composing the roof of the coal bed. The ratio of this
fine mud or slate impurity in coal can increase until the former
predominates, causing the product to lose its rank among the use-
ful family of coals.

The usual law, with some exceptions, is that this slate impurity
in coal carries with it iron pyrites, FeS2 (a compound of sulphur
and iron), so that the volumes of these undesirable impurities are
usually found in a varying proportion to the amount of ash in the
coal, increasing generally as the ash increases. But there are
exceptions to this law.

Varieties of Coal. — It is assumed that what is now ranked as
bituminous coal represents the normal condition of all true coal
prior to the subsequent changes by the agencies of heat.

Fig. 1 illustrates, in a general way, the chemical and physical
changes in the formation of the several varieties of coal, from its
organic constituents in plant tissue to the last result in graphitic
carbon.

TREATISE ON COKE

Prof. Joseph Le Conte has given the approximate composition
of these typical varieties of bituminous coal and graphite, and has

10 20 30 40 50 60 70 80 90 100

Cellulose. . .
Peat . .

Lignites or brown
coal

Bituminous. .

Semibituminous . .
Semianthracite . . .

Anthracite

Graphite

FIG. 1. DIAGRAM SHOWING GENETIC RELATIONS OF THE
CARBON MINERALS, AFTER PROF. J. S. NEWBERRY

constructed the following chemical formulas showing the changes
under which they were formed:

Vegetable matter, cellulose

Subtract 9 CO2, 3 CH4, 11 H2O ........ C12H34O2

And there remains ................... C24//26O

Vegetable matter

Subtract 7 CO2, 3 CH4, 14 H2O

And there remains

Vegetable matter C3

Subtract 10 CO2, 10 C7f4, 10 H2O C2

And there remains. . . .C,

cannel

= bituminous coal

= graphite

The table on the following page exhibits the principal elements
of the genesis and varieties of coals.

From this table will be noted the gradual changes effected
during the lapse of time, in which plant tissue has been subjected to
natural distillation. In the western coal fields we have impressive

*The composition of wood timber is usually given as about C12HISOS.
I have taken the formula of cellulose instead, viz., C6HWO5; or, taking six
equivalents for convenience of calculation, C^H^f)^. I believe this to be
much nearer the composition of the vegetable matter of the coal period
than is the formula of hardwood like oak or beech. All the results may be
worked out, however, with equal ease by the use of either formula for vege-
table matter.

TREATISE ON COKE

examples of such changes, in the localities of trap outbursts, altering
the Cretaceous or Tertiary coals to good bituminous and anthracite
varieties. To what extent this metamorphism has affected many
localities of far western coals that are now profitably used in the
manufacture of coke, is not clearly made out. It is submitted by
some observers, that the chief element that has altered these western
coals into the many varying grades in which they are found to exist,
is the pressure from upheaval and flexure.

PRINCIPAL ELEMENTS OF THE GENESIS AND VARIETIES OF COALS

Names

Moisture
Per Cent.

Volatile
Matter
Per Cent.

Fixed
Carbon
Per Cent.

Ash
Per Cent.

Sulphur
Per Cent.

Phos-
phorus
Per Cent.

Cellulose

55.36

41.44

3.00

.20

Peat

24.20

27.00

45.30

3.30

.20

Lignite
Brown coal

27.90
29 06

66.09
66 31

4.00
2 27

1.00
2 36

Cannel

2.10

14.99

68.13

12.30

2.48

Albertite
Bituminous .

1.78

13.68
35 36

86.04
58 29

.10
3 89

trace
68

trace

Semibituminous . .
Semianthracite . . .
Anthracite
Graphite . ,

1.20
2.27
2.98

23.89
8.83
3.38

67.56

78.83
87.13
99.00

6.69
9.39
5.86
1.00

.66
.68
.65'

. .005

the evident cause of these
in the neighborhood of trap

It will be noted, however, that
changes in the varieties of coals,
dikes or outbursts, with the resultant heat, is easily understood,
but in large areas of coal deposits, without any evidence of erup-
tive heat, the cause must be sought in other conditions.

The rich bituminous coals of Western Pennsylvania, the semi-
bituminous coals on the eastern flank of the Alleghany field, the
pure, glassy anthracite of the eastern fields, and the graphitic anthra-
cite of the state of Rhode Island all belong to the same age — the
true Carboniferous period. From the analyses of these coals, it will
readily appear that the largest evolved products of natural distilla-
tion occurred in Rhode Island, moderating in its action, westwardly,
until the normal condition of bituminous coal is found in Western
Pennsylvania and Ohio. While there may exist some conflict of
opinion as to the cause of this debituminization of coal eastward,
the fact that such has been consummated is not in dispute.

In considering the cause or causes that have produced the
various conditions of coals, the fact is quite evident that all the
anthracites in Rhode Island and in Eastern Pennsylvania are found
in sections that have been violently flexed and tilted. This work
of folding and flexing the eastern flank of the continent must have
been accompanied with a large amount of evolved heat, as the
pushing forces exerted must have been enormous. As all the

TREATISE ON COKE 23

measures in these sections have been baked with heat in about the
proportion to the violence of the disturbance in each locality, it is
evident that the cause or causes have been as extensive as the
results. Hence, it has been inferred that the heat evolved in the
flexing of the measures, combined with moisture and pressure,
have been the chief agents in producing the conditions that have
made the several varieties of coals — anthracite, semianthracite,
and bituminous.

The origin of this dynamic or folding force evidently had its
source mainly from a cooling globe. The rigidity of the rock belt
along the Atlantic Ocean seaboard confined the main body of this
force to the softer inland crust, the latter being crushed and flexed
in proportion to its proximity to the rigid seaboard belt, beginning
at the seaboard with the largest crust waves, moderating into
ripples, and as Ohio is reached, the measures are nearly horizontal.
The heat evolved in these great crust movements altered the
eastern coals into graphites, anthracites, and semianthracites, the
coals regaining their normal condition westward beyond this region
of intense disturbance.

This general law of the bituminization of coal westward has
some slight exceptions. At the summit of the Alleghany Moun-
tains, at Bennington, the coal contains 23 per cent, of volatile matter,
while an exceptional belt at Johnstown, 26 miles westward, con-
tains less than 20 per cent, of hydrogenous matter. From Johns-
town westward, the increase of volatile matter is quite regular
until the maximum belt of the normal bituminous coal is reached
in Western Pennsylvania and Ohio.

The coals of the eastern anthracite fields have been thoroughly
coked under immense pressure, making this natural coke too dense
for the best results in blast-furnace operations. This undesirable
physical condition of extreme density will be fully considered later.

The manufacturer of coke can, therefore, intelligently consider
the qualities of the coals in the Appalachian and western fields for
use in making coke. As the dynamic force that flexed and folded
the eastern side of the North American continent exerted its greatest
force at the east, diminishing gradually westward, the evidence of
the action of the diffused heat from these movements is seen in its
effect in the hard, dry anthracite coals of Pennsylvania and Rhode
Island, the dry semibituminous coals of Broad Top and Cumber-
land, with the increase of bituminization of the coals westward,
until the normal undisturbed condition is reached in the great cen-
tral plain of the continent.

The table on the following page gives the composition of the
typical varieties of coals, from Rhode Island to Iowa.

It is also of interest to consider the irregular curved lines of the
eastern escarpment of the great Appalachian coal field, with the
deeply curved indents in Pennsylvania and Tennessee, displaying
the immense forces that have flexed and pushed back bodily these

TREATISE ON COKE

portions of the field, with measures 8 to 9 miles thick. In the sub-
sequent erosion, Tennessee and Alabama suffered most, having had
the dryer sections of their coals carried away and leaving the more
western sections, with their increased volumes of volatile matter,
for the manufacture of coke.

TABLE EXHIBITING THE DEBITUMINIZATION OF COALS— EASTWARD

Moisture
Per Cent.

Volatile
Matter
Per Cent.

Fixed
Carbon
Per Cent.

Ash
Per Cent.

Sulphur
Per Cent.

Iowa

1.40

41.40

48.50

7.50

1 20

Illinois

1.25

41.85

48.90

7.00

1.00

Indiana

1.10

37.06

57.59

3.50

.75

Ohio

2.70

33.49

56.90

5.99

.92

Pennsylvania
Pittsburg

1 28

38 10

54 39

5 44

Connellsville
Johnstown

1.25
1 03

31.79
16 49

59.80
73 84

7.16
7.97

.60
1 97

Bennington
Maryland, Cumberland. . . .
Pennsylvania
Semianthracite

1.20
.89

1.25

23.33
15.52

9.60

69.02
74.29

81.30

5.69
8.59

6.90

.76
.71

.85

Anthracite

1.35

3.45

89.06

5.81

.30

Rhode Island, Graphite
Anthracite

1.18

3.80

85.70

8.52

.80

It has been noted that in the meridional sections of this coal
field, if not in all fields, the qualities of the coal in the several beds
approximate very closely in their chemical composition; so that if
a good coking coal in found in any of the beds in a special section,
all of its associated beds, above or beneath, will probably afford
similar good results in coking.

COMPOSITION OF COKING COALS

While it is not yet clearly determined why one coal will fuse in
the coke oven and make good coke, and another of very similar
chemical composition will not fuse in coking, yet, in the Appa-
lachian field, it has been found reasonably sure that coals, approxi-
mately equal in chemical composition, will afford similar results in
the process of coking.

The following analyses will show the composition of the standard
typical coking coals in the Appalachian field.

It is quite remarkable that the standard coking coal of the Con-
nellsville region is found in a long, narrow synclinal strip, west of
the Chestnut Ridge. It affords a coal with an average chemical
composition between the rather dry coals to the eastward of it
and the too bituminous coals westward.

TREATISE ON COKE

ANALYSES OF STANDARD APPALACHIAN COKING COALS

Moisture
Per Cent.

Volatile
Matter
Per Cent.

Fixed
Carbon
Per Cent.

Ash .
Per Cent.

Sulphur
Per Cent.

Pennsylvania
Bennington
Connellsville

1.73
1.26

23.89
31.79

67.03
59.79

6.69
7.16

.66
.60

West Virginia
Monongah

1.52

37.96

53.27

6.03

1.22

Pocahontas ....

.69

19.96

73.02

5.67

.66

Kentucky ....

1.80

32.34

60.10

5.10

.66

Tennessee

1.50

32.51

59.33

5.82

.84

Alabama

1.65

32.48

60.15

4.82

.90

ANALYSES OF APPALACHIAN COALS

Coal Fields

Moisture
at 212° F.
Per Cent.

Volatile
Matter
Per Cent.

Fixed
Carbon
Per Cent.

Ash
Per Cent.

Sulphur
Per Cent.

Second Geological
Survey of
Pennsylvania

Cumberland ......

.893

15.522

74.289

9.296

.714

HHH, p. 101

Broad Top
Bennington
Johnstown
Blairsville
Connellsville
Greensburg

.770
1.200
.720
.920
1.260
1.020

18.180
23.680
16.490
24.360
31.800
33.500

73.340
68.170
73.840
62.220
59.790
61.340

6.690
5.730
7.970
7.590
7.160
3.280

1.020

.620
1.970
4.920
.530
.860

Kelly (D)1
. Miller (B)
C. I. Co. Dr. F.
HHHH, Unwshd
C. I. Co. Dr. F.
MM, pp. 23, 24

Irwin
Armstrong Co.

1.410
.960

37.660
38.200

54.440
52.030

5.860
5.140

.640
3.660

MM, p. 22
MMM, p. 56

Whether this quality of coal will be found in the extensions of
this strip northeastward and southwestward, paralleling the trend
of the Appalachian mountain ranges, is yet to be learned. In
other words, it is not yet known what were the ultimate effects
of the heat diffused during the period of the flexing of the coal
measures in fixing the condition of the quality of the coal as regards
leanness or richness in bituminous matters.

The following shows the average composition of the celebrated
Durham coking coal, England:

PER CENT.

Moisture 90

Volatile matter 13 . 00

Fixed carbon 80 . 80

Ash 4.39

Sulphur .91

It is very remarkable that this Durham coal, with its very low
volume of volatile matter, fuses so thoroughly in the coke oven
(beehive) and produces first-class coke. Such a well-determined
result adds to the perplexity of the investigation to determine the
reason why one coal will coke and another will not.

TREATISE ON COKE

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TREATISE ON COKE 27

It may be interesting to compare the composition of some coking
and non-coking coals from the Carboniferous measures and from the
Jura-Cretaceous deposits.

It is submitted as an established experience that the approximate
chemical analyses of coals will not disclose their coking properties.
It is therefore evident that in determining the type of coke oven,
with the proportions of its chamber, walls, flues, etc., the only safe
plan is to have a sufficient quantity of coal coked in the several
plans of ovens, or tested in some reliable experimental plant.* In
this respect it may be added that in coking the coals low in volatile
combustible matters in any type of oven, it will be found of great
benefit to break the coal to such sizes as will conduce to the most
economic results in fixing the fusing matters in the initial opera-
tion of coking. With coal charged into the oven in large lumps, it
is evident that, as the coking begins on the outside and moves
slowly into the interior of the lumps, the gases in the central portion
must be dissipated in more or less volume, depending on the dry ness
of the coal and the size of the lumps.

The oven will also be required to be kept at a maximum heat
when charging the coal into it. With the disintegration of the coal
and the sustained heat of the oven, the small volume of fusing
matters in the coal can be promptly fixed in the coke and their
dissipation with the gases prevented.

As the Appalachian coal field affords the greatest supply of
coking coals, the careful study of the approximate analyses of these
becomes of the first importance, so that the coke oven best adapted
for the several varieties of coals can be intelligently selected.

In the Appalachian region, the analysis of the coal will, in most
instances, indicate its coking properties, but westward the coals
having compositions similar to good coking Appalachian coals fail
to fuse in the coke oven. Pennsylvania, Virginia, West Virginia,
Kentucky, Tennessee, and Alabama have been especially favored
by large areas of good coking coals in this great field of 59,370 square
miles. The eastern side of the field affords the coking coals best
adapted for making metallurgical coke. The western side inherits
too much bituminous matter to assure very good coke. This law
is shown in the pitchy coals of Ohio, Indiana, and Illinois and by
the small amount of coke made in these states.

The coals of Colorado, Wyoming, Montana, and the other north-
western states, belong to the Jura-Trias and Laramie- Cretaceous
measures, and are independent of the Appalachian law of ratio of
volatile hydrocarbons to fixed carbon, as some of these coals can
be coked readily in the common beehive coke oven, as at the

*There are reliable establishments in the United States for testing the
washing and coking properties of coals, such as the Link-Belt Machinery
Company, Chicago, Illinois; Messrs. Stein & Boericke, Primes, Delaware
County, Pennsylvania; Roberts, Schaefer & Company, 1275 Old Colony
Building, Chicago, Illinois; and the Jeffrey Mfg. Co., Columbus, Ohio.

28 TREATISE ON COKE

Trinidad or El Moro, the Crested Butte, and other coke works of
Colorado, the Cambria Mining Company, of Wyoming, and the
Bozeman and Gardner coke works, of Montana. On the other
hand, a large portion of these northwestern coals, very high in
hydrogenous matters, cannot be coked.

It is slowly becoming evident that the solution of the coking
or non-coking properties of coals is entirely confined to the relations
and volumes of the elements composing the volatile combustible
matters of the coal. The moisture, fixed carbon, ash, and sulphur
may differ widely in good coking coals, without seriously affecting
their coking properties. An example of this is seen in the very
large difference existing in the volumes of carbon and ash in two
of the best-known coking coals, Connellsville and Pocahontas;
the former containing 59.79 per cent, of fixed carbon and the latter
72.70 per cent. The ash is neutral, exerting no influence in the
fusing of coal in coking. The sulphur and phosphorus come under
the same condition — they are simply undesirable elements in the
metallurgical coke.

It is evident that large differences exist in the volumes of the
volatile combustible matters in the coking coals of the Carbon-
iferous age in the Appalachian field. From the percentages of
volatile combustible matters in these coals, their relative coking
properties can be confidently predicted. These percentages of vola-
tile combustible matter for a coking coal range, in ordinary coke
ovens, from 17 to 33 per cent.; with retort ovens and their recu-
perative and regenerative auxiliaries, coals inheriting much lower
percentages of volatile combustible matters can be coked. The
only further remark in this connection is, that in coking coals
with small volumes of volatile combustible matter affording insuffi-
cient heat for coking, the balance of the heat required must come
from the fixed carbon of the coal.

As a unit of carbon affords about 8,000 calories of heat, while
a unit of hydrogen affords 34,000 calories, it will readily appear that
coals low in hydrogenous matters must surrender, in the ordinary
open ovens, an increased volume of fixed carbon to compensate for
the deficiency in the reduction of the greater heat-giving hydrogen.

The loss of carbon in the open coke ovens, especially in coking
the dry coals, was evidently the impelling element in the evolution
of coke ovens, and in developing the retort or closed ovens with their
auxiliary recuperative and regenerative appliances, and in the
utilization of the gases from the coking coal in heating the oven
chamber and saving the fixed carbon in coking. To assure sus-
tained heat, as well as from the peculiar construction and length
of these retort coke ovens, the charges of coke require to be drawn
by mechanical appliances.

Returning to the evidence submitted, locating the fusing element
or elements in coals of the Appalachian age, in their volatile com-
bustible matters, it was shown that wide differences in the volumes

TREATISE ON COKE 29

of fixed carbon could exist in these coals, producing, as far as is now
known, only slight modifications in their coking qualities.

It has been made evident by practical experience that in the
Appalachian region coals containing 18 to 35 per cent, of volatile
combustible matters can be made, with proper oven treatment, into
good coke. Northwestward, among the more recent deposits of
coals, the ratio of volatile hydrocarbons to the fixed carbon does
not indicate, with some exceptions, their coking properties, as
some of these coals inheriting 35 to 45 per cent, of these matters
fail to fuse in any type of coke oven.

It has been noted in the reports of the United States Geological
Survey that a coal found in Alaska, and containing the following
elements, could not be coked:

ALASKA COAL PER CENT.

Moisture, 212° F 9.31

Volatile combustible matters 40 . 85

Fixed Carbon 46 . 14

Ash 3.70

100.00

. But in the Jura-Trias and Laramie-Cretaceous coals, this Appa-
lachian law will not, as a general rule, be found reliable. This
will be seen in the efforts to coke the large samples of the Sand-
coulee and Belt Mountain coals of Montana. In comparing their
volumes of volatile combustible matters with the Connellsville,
their close relations will appear as follows:

Connellsville, Pennsylvania. . . 31 . 80 per cent, of volatile combustible matters

Sandcoulee, Montana 33 . 60 per cent, of volatile combustible matters

Belt Mountain, Montana. ..... 28. 71 per cent, of volatile combustible matters

Connellsville coal is the standard coking coal of the United
States, as far as present knowledge has disclosed; the coals of Sand-
coulee and Belt Mountain are mainly non-coking.

Tests of Sandcoulee and Belt Mountain Coals. — A shipment of
coal from Sandcoulee, Cascade County, Montana, was tested at the
coke works of the Cambria Iron Company, in the Connellsville region,
in 1889. A general average of this coal from a bed 6 feet 6 inches
to 8 feet 6 inches thick, showed the following composition:

PER CENT.

Moisture at 212° F 2. 260

Fixed carbon 54. 470

Volatile combustible matters 33 . 600

Ash 7.820

Sulphur 1 . 850

Phosphorus 009

' 100.009

30 TREATISE ON COKE

The two benches of this coal bed differed in quality ; the upper
bench affords a dull, dry coal, the lower bench is brighter and more
fusible in the coke oven. The coke was made from an average of
both benches — it was analyzed as follows:

PER CENT.

Fixed carbon 88 . 350

Ash 10 . 850

Sulphur 1.790

Phosphorus 009

100.009

The coke exhibited a composite structure; the coal from the
upper bench did not fuse. The coking operation expelled the vola-
tile matters, leaving the normal structure of the pieces of coal
unchanged — it was simply charred coal. This coal received pre-
paratory treatment in various ways before it was charged into the
ovens — it was broken into small pieces, wetted, etc. The operations
of coking were also varied, from slow, mild heat to quick, intense
heat. The latter method gave the better results. The coke was
made in the beehive ovens with great care and by expert cokers.
The ultimate decision was that, while the Cretaceous coal is well
adapted for generating steam arid for domestic and other uses, it
does not fuse in coking so as to produce a merchantable coke.

Another sample of coal, from the Belt Mountain, 14 miles south
of Sandcoulee, Montana, was forwarded to Connellsville for test in
coking. The coal bed has three benches, the average analysis of
these is as follows:

BELT MOUNTAIN COAL PER CENT.

Moisture, 212° F. . . 2.980

Volatile combustible matters 28 . 720

Fixed Carbon / 53 . 310

Ash 13.340

Sulphur 1 . 650

Phosphorus 012

100.000

This coai, under repeated efforts in coking, came out of the
oven charred; it could not be coked.

On the other side, the Trinidad and El Moro coal of Colorado,
located in the Cretaceous measures, and holding 29.82 per cent, of
volatile combustible matters, affords a very good coke in beehive
coke ovens.

This important inquiry, as to the composition of coals that will
fuse in the coke oven, has elicited and , continues to invite much
earnest investigation from chemists, and while some approaches
have been made in ascertaining the element or elements that pro-
duce fusion of the coal in coking, yet these are not fully assured as
general principles that can be relied on for universal application.

It is reported that some German chemists have made tests to
ascertain the cause of the coking or fusing of bituminous coal in the

TREATISE ON COKE 31

coke oven under distilling heat, the conclusion being that the fusing
property of the coal is produced by its richness in what is known
as disposable hydrogen, or that portion which is in excess of .the
quantity required to form water with the oxygen present. It has
been shown that such a standard for the fusing quality of coal does
not correspond with observed results. So that we have in this no
sure ground for such determination.

The richness of the coal in carbon does not appear to govern its
fusing capabilities, the fact being that two samples of coal of prac-
tically equal carbon composition will be found to behave very
differently in coking in the ovens. It is evident that if the genesis
of fusing does not reside in the surplus hydrogen or fixed carbon, it
certainly does not lie in the oxygen, as the latter affords no indica-
tion of the physical behavior of coal in the retort of the coke oven.

Fusibility and Coking Properties. — The following extract on the
fusibility and coking property of coals is taken from the American
Manufacturer — the author's name not being given:

"It has been long known that the property of coking which
belongs to many coals — a property which may be observed in
every degree, i. e., from a weak slagging to a complete fusion— is
not a simple or partial fusion, and the fusion of mineral coal is
accompanied rather by a fundamental decomposition of the same,
just as is the case when sugar is subjected to a high heat, whereby
are generated gases and vapors burning with a more or less lumi-
nous flame and leaving behind them a fused residue consisting
chiefly of carbon.

"The very natural supposition that the fusibility or infusibility
of a coal must always stand in fixed ratio to its proportional com-
position is not at all borne out by practice, although a number of
isolated cases may seem to give it support.

''Percy (Metallurgy) found the following percentages of hydro-
gen, oxygen, and nitrogen in several coking and non-coking coals:

NON-COKING COKING NON-COKING

"l JT ' 3 ~~T~~ 5 6 7 8 9

H 4.75 4.95 5.49 5.85 5.91 6.34 6.12 6.04 5.99

O and N. . .5.28 7.36 10.86 14.52 18.07 21.15 21.13 22.15 23.42

"The following excesses of hydrogen, over what was considered
necessary to combine with the oxygen to form water, were found,
that is, the remaining quantities of disposable hydrogen:

NON-COKING COKING NON-COKING

1 2 ' '3 4 ~~F ' 6 7 8 9 '

H 4.09 3.53 4.13 4.04 3.65 3.70 3.47 3.22 3.06

"The property of coking evidently cannot depend on this dis-
posable hydrogen, since, for instance, in Nos. 1 and 4, non-coking
and coking coals respectively, it is very nearly the same.

32 TREATISE ON COKE

'The sum of hydrogen and oxygen in these nine coals is:
NON-COKING COKING NON-COKING

10.03 11.81 16.35 20.37 23.98 27.49 27.35 28.59 29.41

"From this it might be inferred that a content of 7-18 per
cent, of oxygen entails the property of coking. The results in
the table on the opposite page, obtained from the experiments
of W. Stein and of the author, however, are totally against such
an inference.

"Of the Saxon coals, for instance, Nos. 7 and 8, as well as
Nos. 9 and 10, while having a very similar composition, show
entirely different results by the coking test. The same is true of
each pair of the Westphalian coals analyzed.

"For single coal fields, it is, of course, possible to establish some
limits. Richter, for instance, has done this for the coals of lower
Silesia, though only in an introductory way:

"(a) So-called coking coals contain, with few exceptions,
40 parts of disposable hydrogen per 1,000 of carbon.

"(6) In case of equal content of disposable hydrogen, the
coking power increases the more the combined hydrogen falls
below 20 per 1,000 of carbon. Coals of 20 per 1,000 content
of combined hydrogen, and even those of 17 to 18 per 1,000 do
not, in lower Silesia, belong to the number of coking coals,
properly speaking.

"(c) Although the above may be accepted as the rule, it must
still be noted that sometimes coals of almost the same composition
show very different coking properties.

"A sort of rule may be deduced as follows, from the analyses
of several hundred Westphalian coals:

"(a) Coking coals (swelling in the process of fusion) contain,
per 1,000 parts of carbon, over 40 of disposable hydrogen and 10
of combined hydrogen, or under 40 of disposable hydrogen and
over 9 of combined hydrogen.

"(6) Open-burning or slagging coals (that is, fusing, but not
swelling) contain, per 1,000 of carbon, over 34 of disposable hydro-
gen and over 9 of combined.

11 (c) Close-burning coals contain, per 1,000 of carbon, under
40 of disposable hydrogen and under 9 of combined.

"The property of fusing or not fusing finally depends on the
presence or absence of certain carbon compounds, of which inti-
mate knowledge is probably not attainable."

Mr. Richard Thomas, in "A Paper on Coke," read before the
Alabama Industrial and Scientific Society, submits a tabulated
statement showing the ultimate composition of some Welsh coals,
and from the coking or non-coking properties of these, infers that
the fusing element in coals consists of the relations of the hydro-
gen to the carbon.

TREATISE ON COKE

-2

T— *4 IV

8 3

- g

M C

002OOOOC/20OO :

'S
two

O O
00 CD

IOCO

|>CO

1C 1C

t> co

Tt< CO

I>CO

COCOCOCOCOCOCOCOfMCO

s s

O CO
i— i O <N (N t> CO 00

s g s.

i-H CO

CCOOOC00000000001>I>

00 Is* Is*

00 0000

'S'S

+j ' • "J OU

O „ 1 <U O'

* g^-o °

^S o «
C^ o ^> c

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.« s fi o 6'

34 TREATISE ON COKE

TABLE SHOWING COMPOSITION OF WELSH COAL

No.

Per Cent.

H
Per Cent.

Per Cent.

5
Per Cent.

Ash
Per Cent.

91.44

3.46

.21

2.58

.79

1.52

84.87

3.84

.41

7.19

.45

3.24

89.01

4.49

1.16

1.65

1.03

2.66

89.78

5.15

2.16

1.02

.39

1.50

81.72

5 76

.56

8.76

1.16

2.04

87.48

5.06

.86

2.53

1.03

3.04

82.75

5 31

1.04

4.64

.95

5.31

TABLE SHOWING AMOUNT OF COKE AND WHAT WAS VOLATILE

No.

Coke
Per Cent.

H
Per Cent.

Per Cent.

Hydrogen to Carbon

92 90

3.46

.21

2.58

.85

{c2e.4}Anthracite

85.50

3.84

.41

7.19

3.06

f 7-7 1 i

{ C 22 1 } Semianthracite

84.55

4.49

1.16

1.65

8.14

( J-f 1 i
\C 19 8/ Bituminous

77.50

5.15

2.16

1.02

14.18

{TT I ~.
C 17 4 /Bituminous

68.40

5.70

.56

8.76

16.58

r J-f 1 i
< ^ +'„ > Bituminous

72.94

5.06

.86

2.53

18.61

{/•/ 1 i
C 1 7 1 I Bituminous

67.10

5.31

1.04

4.64

21.91

{^gjBitummous

Mr. Thomas gives the following descriptions of the above coals :
"Coal No. 1, or Welsh Anthracite. — This coal will not fuse,
neither will the lump coke like the other coal. The analysis shows
92.9 per cent, of coke from the coal. In appearance, it is more like
a drying up coal than coke. In place of cells, it looks more like
cracks. By disintegrating the coal, and using about 6 per cent, of
pitch, the latter being about 12 per cent, of hydrogen to 88 per
cent, of carbon, the two combined make a very strong coke. The
fracture did not show the cells the same as the coking coal, but was
granulated in appearance. They claim that it works well for
foundry purposes and commands a price from 3 to 4 shillings per
ton more than the coke made in the same locality from the bitu-
minous coal. The loss in volatile matter in this coal is very small.
The difference in carbon from coal to coke is less than 1 per cent. ;
the analysis shows 3.46 per cent, of hydrogen, and 2.58 per cent, of
oxygen. It seems, by the proportion of volatile carbon to the
amount of oxygen, that the two had combined into carbonic oxide.
Had the carbon and the hydrogen combined, it would have formed
the light carbide of hydrogen, which is composed by weight of

TREATISE ON COKE 35

75 per cent, of carbon to 25 per cent, of hydrogen. In that case,
there would have been a loss of over 10 per cent, of carbon. On
the other hand, if the amount of oxygen had combined with the
hydrogen and formed water, the amount of hydrogen would not
have exceeded .32 of 1 per cent. It is very clear that the hydrogen,
in the anthracite, must have escaped almost in a pure state from
the coal, and mixed with the oxygen of the air and formed water.

"Coal No. 2 has a little more hydrogen, and like No. 1 it will
not fuse, neither will it coke, only when mixed with pitch, or some
of the other solid volatile carbons. This coal would have to be
treated the same as No. 1 to make coke. The coking of No. 1
was discontinued for a time, owing to the advance in the price of
pitch, there being such a demand for the article to mix with the
dry non-fusible coal, to make patent fuel.

"Coal No. 3. — This coal is known, the world over, as the Aber-
dare and Merthyr smokeless steam coal. This is 2.33 less in carbon
than No. 1, but higher in hydrogen, by a little over 1 per cent.
It has only 1.65 per cent, of oxygen, and it shows a loss of carbon
in coking of 8.14 per cent., the oxygen being so low.

"The carbon, in this instance, must have formed gas, most likely
the light carbide of hydrogen. This coal has not sufficient hydrogen
and carbon to fuse, but the lump makes a good furnace coke and
is used very extensively. The slack of No. 3 will coke when dis-
integrated with richer coal, in proportion about half and half, or
when the hydrogen would be about 5 per cent, in the coal — or, say,
1 per cent, of hydrogen to 17.5 carbon. The two combined will
yield about 75 per cent, of coke from the coal.

"Coal No. 4 will fuse and make a strong coke, and is a coking
bituminous coal. I have noticed that, whenever it gives, say,
75 per cent, of coke from the coal, the color of the coke is dark
gray and shows the cells very clearly; but it will not have a smooth,
silvery gloss on it. None of the dry coals have.

"Coal No. 5. — This coal shows 8.06 per cent, less carbon than
No. 4, but it has 7.74 per cent, more oxygen in it, and has also
.61 per cent, more hydrogen. The hydrogen is 1 to 16 of carbon.
This will make a bright coke of silvery appearance.

"Coal No. 6 makes a good furnace coke, and shows the cells a
little darker gray in color, the yield being rather high to be glossy.

"Coal No. 7. — This coal cokes more like the Connellsville, of
Pennsylvania, than any I have ever seen. This coke, in appear-
ance, has a very smooth, silvery gloss when cooled in the ovens.
The best coke in this series is made from a vein called the Crepwr
vein. It makes a good, strong furnace coke, and is largely used
for foundry purposes. Owing to a slate roof, some of which falls
in mining, the slack in some of the mines is washed, but the vein
is free from all impurities, and averages about 8 feet thick."

He concludes that No. 1 coal, with a proportion of hydrogen to
carbon of 1 to 26.4, will not fuse in the coke oven. No. 2 coal, with

36 TREATISE ON COKE

a proportion of 1 to 22.1, will not coke. No. 3, a smokeless steam
coal, inheriting a proportion of hydrogen to carbon of 1 to 19.8,
will not fuse readily. Nos. 4 to 7 embrace the fusing or coking
coals. The best relation of hydrogen to carbon among these is
found in No. 7, which is reported as producing a coke "more like
the Connellsville." This coal has a proportion of 1 to 15.6; hence,
it is inferred that coals inheriting ratios of hydrogen to carbon, as
the series from 4 to 7 show, are good coking coals.

It may be of interest to note that the Connellsville coking coal
inherits relations of hydrogen to carbon, in its composition, of 1 to
14 nearly. The Monongah coal of West Virginia contains the
relations of hydrogen to carbon of 1 to 10.7. The celebrated
Durham coking coal of England has a proportion of 1 to 17.2. All
these coals fuse in a very thorough manner, making excellent
metallurgical coke.

On the other side, a readily fusing coal from Ohio has its
hydrogen to carbon as 1 to 9.8, which indicates a close relationship
to the West Virginia variety.

In the Saxony and Westphalia coals, two samples of coal afford
proportions of 1 to 17.4 and 1 to 17. 6 respectively; the former made
a crumbling coke, while the latter was "caked and much swollen."

These investigations indicate progress, but do not go far enough
in embracing the different varieties of coals with their varying con-
ditions to enable the coke manufacturer to determine accurately,
from the ultimate analysis of his coal, whether it will fuse in the
oven and make good metallurgical coke, or if it is a non-coking
coal. So far as the more recent investigations indicate, the coking
property of coal depends on the presence of certain relations of
hydrogen and carbon, with the interaction of these from certain
conditions not yet definitely established.

Prof. W. Carrick Anderson, of the University of Glasgow, Scot-
land, submits, in a paper read before the Glasgow Philosophical
Society, that, in every case, the quantity of hydrogen and oxygen
contained in the coal plays a more important part than the carbon.
Coals very rich in hydrogen and in oxygen no longer melt, neither
do those very poor in hydrogen and oxygen. He gives the table
on the following page exhibiting the series of solid fuels, arranged
with reference to their chemical composition and yield of coke.

He adds that it is evident from this series that the coking
property is in some measure bounded by the following limits:
hydrogen, 5 to 6 per cent. ; oxygen, 10 per cent. ; free hydrogen,
4 per cent.; and specific gravity, 1.35. Such a statement cannot,
however, by any means be regarded as a rule of general applica-
tion, especially seeing that cases of isomerism occur among coals
in which, in two coals identical in composition, the one cokes and
the other does not.

Until the exact relations of the coking elements of coal are
assuredly determined, it will be the safest course, in ascertaining

TREATISE ON COKE

the coking properties of the coal, to have a sufficient quantity of
it tested in a coke oven. This will settle the whole matter beyond
any doubt.

SERIES OF FUELS

Kind

C
Per

Cent.

H
Per

Cent.

O
Per

Cent.

Free
H
Per

Cent.

Coke
Yield
Per
Cent.

Specific
Gravity
Per Cent

Time of Formation

Wood

44
60
65
75
80
85
90
95

100

6
6
7
6
6
5
4
2

50
34
28
19
14
10
6
3

3
4
4
4
3
H

20
40
50
60
70-80
90
95

100

.35
.60
1.00
1.25
1.30
1.35
1.40
1.50
(1.90)
2.00

> Present day
Tertiary and chalk

Carboniferous
period

Silurian

Peat
Brown coal
Coal (a) flaming.. .
Coal (6) gas

Coal (c) coking. . . .
Coal (d) lean coal .
Coal (e) anthracite
(and coke)

Graphite

The Connellsville coal, found in the upper coal measures and at
a certain distance from the eastern seaboard, is especially adapted
for the manufacture of coke. It holds practically 32 per cent, of
volatile matter. The bed is 8 to 10 feet thick, and the coal has a
decided columnar structure. In mining, the coal crumbles into a
finely divided condition, well adapted, without further preparation,
for charging into the coke ovens.

The central West Virginia coals are much more bituminous than
the Connellsville, the Monongah coal inheriting 38 per cent, of vola-
tile matter, while the Pocahontas coal, in the southeastern side of
the state, holds only 20 per cent, of volatile matter. These are the
typical coking coals of these sections of the Appalachian field.

The Kentucky, Tennessee, and Alabama coals approach in
percentage of volatile matters the Connellsville coal, and make
very good coke.

In the central and western fields the coals are quite rich in bitu-
minous matters, and as yet they have not been distinguished in the
manufacture of coke. With our present inexperience in the best
methods of treating these coals, in preparing them for coking, and
in the use of the oven best adapted for securing good coke, few
attempts have been made in these respects. It is evident that
experimental work along these lines will, in the near future, become
a necessity, especially in eliminating sulphur from these coals.

In the Rocky Mountain and Pacific coast regions no sure infer-
ences can be drawn from the chemical composition of the coal as
to its coking properties. In one locality the coal cokes readily,
making a good marketable coke; in another, a coal with a very
similar composition will not coke, but if placed in an oven it will
part with its volatile matter without fusing — the result will be

38 TREATISE ON COKE

charred coal. The only sure method of determining the value of
such coals for the manufacture of coke is, as before indicated, to
have a quantity of it tested in a coke oven. This will show its cok-
ing or non-coking properties without any doubt. A few dollars
expended in this preliminary work will save a great many in the end.
The kind of coke oven for these special qualities of coal can be
ascertained by consulting some reliable expert in coke-oven plants.

IMPURITIES IN COAL

The impurities in coal consist of ash, sulphur, and phosphorus.
The ash is usually a negative element, having little chemical influ-
ence in the use of coal and coke, unless it is mainly composed of
silicious matter, in which case it will produce "clinkers," which
are always undesirable. It has been pointed out that an excess of
ash in the coal is injurious to the perfect physical development of
the coke, especially in its hardness of body. Economically con-
sidered in coke for blast-furnace use, it not only displaces carbon,
but requires increased charges of limestone and coke to dispose of
it in the slag. Some qualification to this has been indicated in
the smelting of the dry Lake Superior ores, that the ash in coke
contributes somewhat to the formation of slag in the furnace — but
ordinarily it is an expensive application.

The sulphur in coal is usually found in four principal chemical
conditions; viz., sulphide of iron, FeS2 (iron pyrites); sulphate of
lime, Ca5O4; organic sulphur, i. e., combined with carbon, hydro-
gen, and oxygen; and free sulphur, i. e., sulphur not in combina-
tion with iron or other elements.

If sulphur is present in the coal united with lime, as sulphide
of iron, a large proportion of it will be volatilized in coking; but
if it takes the form of sulphate of lime, gypsum, it will not be
volatilized in a coke oven. The organic sulphur remains, for the
most part, in the coke.

The table on the opposite page shows the percentage of sulphur
volatilized in coking.

This table is from volume MM of the Second Geological Sur-
vey of Pennsylvania, by Prof. Andrew S. McCreath. Professor
McCreath adds: "Seven coals with an average of 63.51 per cent,
of their sulphur existing as free sulphur lost 34.57 per cent, of the
sulphur by coking; on the other hand, eleven coals, with an average
of only 11.36 per cent, of sulphur not combined with iron, lost 37.88
per cent. Again, two coals, with an average of 74.58 per cent, of
the sulphur free, lost 20.97 per cent, by coking; while two other
coals, with only 2.20 per cent, of the sulphur free, lost 44.81 per
cent. In the presence of such results, therefore, it would seem to
be impossible to accept the statement that all the free sulphur
passes off with the volatile matter in the process of coking.

TREATISE ON COKE

JI;S g

0.5 O

(MOCOOtCOOOC'-HOO
(TOOOi

b- oo »c

,-H CO T-H T-l Cq ,-H

OOCOOOOt^
iT-HOiOO(

i- C<

<NOO^f<M<N
lOOlOiOit— l
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cDt^i— > OS CD CD <N O
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b>: bjo g two be

S 3 <u ^QQOPQpqpQPQ fe ^

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. ^,

40 TREATISE ON COKE

"In the 25 coals examined, the percentage of sulphur expelled
by coking varies very much, the maximum amount being 57.92
per cent., and the minimum 14.75 per cent. The average percent-
age is 38.50; and the average percentage of free sulphur is 33.79.

"Where, therefore, a careful handling and subsequent washing
of the coal will not remove the excess of sulphur, it is scarcely to
be hoped that this can be accomplished by the usual methods in
the coke ovens. And this important consideration should be borne
in mind when selecting coals for the manufacture of coke for use
in blast furnace or foundry."

Effect of Acetic Acid in Removing Sulphur. — An inquiry from
a party in Kentucky, as to the value of acetic acid in reducing the
volume of sulphur in coke, was submitted to Professor McCreath,
who replied as follows:

"A sample of coal containing 3J per cent, of sulphur was coked,
and a spray of hot, diluted acetic acid was thrown on the incan-
descent coke. There was no evidence of the disengagement of
either sulphureted hydrogen, sulphurous acid, or sulphuric acid.
The latter would seem impossible.

"The test was duplicated, using a stronger solution of acetic
acid. The result was equally negative.

"Two separate portions of the same coal were then coked. To
the one nothing was added. This I will designate as 'regular.'
To the other, a spray of diluted acetic acid was added to the incan-
descent coke. The coking process was continued a little, when a
second application was made, completely saturating the coke.
Both the resultant cokes were then weighed, and the 'treated' one
yielded 1 per cent, less coke, due of course to increased oxidation
of the carbon. Finally, both were fused and a determination of
the sulphur made, the results obtained being as follows:

TREATED WITH
REGULAR ACETIC ACID
Sulphur, per cent, in coke 2.987 2.755

"The difference is so slight that the results for all practical
purposes may be considered the same, and they demonstrate that
no desulphurization of the coke takes place under the treatment
submitted."

Phosphorus in the coal usually goes over to the coke; it is not
eliminated in the coke oven.

The investigation of the volume of phosphorus contained in coals
suitable for the manufacture of coke for steel-making purposes,
discloses the fact that this volume of phosphorus varies from a
mere trace to a maximum of .1248 per cent. In the examination
of 24 coals from the large Pittsburg bed, the average was found
to be .0217 per cent., which would give to the coke an average of
.0344 per cent. The great necessity of the utmost care in selecting

TREATISE ON COKE

coals for the manufacture of coke for metallurgical uses as free
from the impurities of ash, sulphur, and phosphorus as possible,
will readily appear. The following table of Pennsylvania coals
affords some typical examples:

PERCENTAGE OF PHOSPHOJRUS IN PENNSYLVANIA COAL AND COKE

Name of Coal

County

Coal Bed

Phos-
phorus in
Coal
Per Cent.

Phos-
phorus in
Coke
Per Cent.

Henderson 's

Washington

1667

2818

Redds'

Washington

Pittsburg

0943

1551

Penn Gas Coal Co
Millwood

Westm'land
Westm 'land

Pittsburg
Pittsburg

trace
0801

trace
1177

Connellsville

Fayette

Pittsburg

.0111

0161

Cambria Iron Co ...

Cambria

trace

LOCALITIES OF PHOSPHORUS IN THE CONNELLSVILLE SEAM

PER CENT. OF PHOSPHORUS

Roof
to
Bottom

Bottom*

Middlet

Topf

Above 5-Foot Binder

Upper
12 Inches

Middle

Lower
12 Inches

.009

.010

.023

.054

.031

.038

.019

.001

.010

.027

.033

.029

.017

.022

.001'

.007

.034

.043

.035

.053

.012

.001

.004

.009

.017

.008

.007

.018

.015

.087

.019

.007

.016

.005

.025

.002

.030

.174

.109

.060

.068

.015

.047

.016

.028

.018

.015

.017

.002

.008

.019

.017

.026

.021

.003

.044

.082

.090

.011

.010

.021

.006

.009

.029

.062

.038

.013

.020

.011

.034

.032

.025

.004

.043

.035

.021

.005

.006

.069

.062

.025

.003

.018

.035

, .006

.079

.013

.003

.114

.022

.014

.105

.019

.013

Average

.0143

.0094

.0186

.0393

.062

.0362

.0277

* Bottom means 3-foot binder down,
t Middle means between 3- and 5-foot binder.
t Top means above 5-foot binder.

§ The upper and lower sample left only about 2 inches of coal between the two; conse-
quently, no sample from the middle was taken.

42 TREATISE ON COKE

Phosphorus in Connellsville Coal. — During the year 1896, Mr.
O. W. Kennedy, late General Superintendent of the H. C. Frick
Coke Company, had a series of tests made to determine the local-
ities of the phosphorus in the Connellsville coal seam. The pre-
ceding table, in detail, will afford the results of these tests. It was
submitted, in explanation, that "this sampling was made at mines
showing phosphorus higher than the average of the region."

It is manifest from this table that the upper section of this
large coal bed contains the greatest amount of phosphorus. It
is also evident that the percentage of this undesirable element
increases gradually from bottom to top of the coal bed.

Effect of Impurities in Coke on Pig Iron. — The sulphur, when
present in coke in large volume, confers on pig metal the undesir-
able property of "red-shortness." Coke for use in blast-furnace
work producing Bessemer pig should not contain over 1 per cent,
of sulphur as a maximum volume. Coke containing .50 per cent,
to .75 per cent, of this element would be much, more desirable in
the manufacture of pig iron for making steel. An undue volume
of phosphorus produces an opposite quality in the metal made by
it — the condition of "cold-shortness" — that is, metals made by
coke containing an excess of these dangerous elements are found
to be brittle in their hot and cold conditions. As little or none of
the phosphorus in the coal is eliminated in the process of coking,
it is of the utmost importance to select coals for the manufacture
of coke for Bessemer uses as low as possible in this dangerous
impurity. The table on page 41 shows .0111 per cent, of phos-
phorus in the Connellsville coal.

Portions of the ash and sulphur can be removed from the coal
for coke making by the processes of crushing and washing (see
Chapter III), but the phosphorus usually goes over in full to the
coke and finally to the pig metal in blast-furnace work.

CHAPTER HI

PREPARATION OF COALS FOR THE MANUFACTURE

OF COKE

Necessity for Preliminary Preparation of Coke. — It is now quite
manifest that we have reached a period, in the United States of
America, in which steel is rapidly displacing iron in the arts and
manufactures, especially for structural uses. This expansion of
the use and manufacture of steel carries with it the necessity for
a pure coke fuel, and it becomes, therefore, the duty as well as
the interest of the coke manufacturer to adopt such methods in
the preparation of coal for making coke as will insure the purest
and best possible product.

Although there is a very great source of supply of coal for the
manufacture of coke, covering an area in the United States of
North America of about 344,440 square miles, it is evident that
only a small portion of these coal fields affords the best coal for
coke making — such as the Connellsville, Punxsutawney, Alleghany,
and Broad Top in Pennsylvania; Pocahontas in Virginia; and the
new regions of coking coals in West Virginia. Alabama also affords
a very good coal for coke making. In Kentucky, at Pineville,
and Big Stone Gap, excellent coking coals are found in abundance.
At El Moro, in Colorado, very good coke is made from a large
bed of coking coal. But with all these and many others yet to
be developed, the aggregate ratio of the best coking coals to the
whole coal area is very small.

As long as the supply of coke can be maintained from these good
coking coals, the methods of coking do not urge or compel extended
consideration ; but when the less valuable coals for coking purposes
come into use, the studies of the preparation of the coal for coking
with the kind of coke oven best adapted for each quality of coal
will become of vital importance. When the time approaches for
these investigations to be taken up by coke makers, it will be found
that three principal conditions will require careful study: (1) the
preparation of coal for coking; (2) the kind of coke oven best
adapted for securing the best quality of coke from each variety of
coal; (3) the saving of the by-products in coking, consisting of
sulphate of ammonia and tar. This will also require arrangements
in coke ovens, as well as the outside conduits, condensers, etc.

44 TREATISE ON COKE

The rather poor quality of coking coals on the continent of
Europe has long ago compelled thorough attention to the prepara-
tion of these coals for coking, as well as to the development of the
oven best suited to their wants in making from them the best
possible coke, and, during the past decade, to the saving of the
by-products in coking. The American coke manufacturer has
before him a much easier task than the Belgium, German, or French
coke makers, the larger supply of coking coal requiring no special
treatment in producing the best qualities of coke. Even when the
exhaustion of these good coals approaches, the second quality will be
found to be superior to the continental coals. From the large and
increasing use of coke, it is evident that its manufacture will demand
the earnest and diligent efforts of those in charge of the several proc-
esses in its preparation and coking. Nor is this industry any excep-
tion to the general law governing all industries: small beginnings,
protracted and anxious struggles for success, with the reward crown-
ing all persistent and well-directed efforts. There is, therefore, a
deep interest attached to the study of the several steps in the upward
progress in the manufacture of coke, especially in its early stages
and up to its present advanced progress in the industrial arts.

Large areas of the best coking coals require no special treat-
ment, but the coals are charged into the coke ovens as they come
out of the mines. In the Connellsville region, with a few excep-
tions, no preparatory work on the coal is attempted, and it is
charged into the ovens as it comes from the mines. On account of
the softness of the coal and its attenuated columnar structure, this
coal is usually broken into small pieces, in mining, and this break-
age, with that due to the handling into tipple bins and larries,
gives pieces sufficiently small to assure good results in coking.
A second type of this coal is found in the Flat Top region of Vir-
ginia. The coal is mined in more solid lumps than the Connells-
ville, but it is broken up, and the screenings are used in making
coke. The bituminous coals of the Central and New River sections
of West Virginia are usually broken and the screenings washed
preparatory to coking.

The manufacture of coke from coal screenings, in the Kanawha
Valley, produces a very good quality of coke, but by using the
whole body of the coal bed, excluding a thin top bench of splint
coal, a coke is made nearly, if not quite, equal to the best standard
Connellsville. The Alleghany Mountain coals are frequently charged
into the ovens as they come out of the mine, but the best results are
assured by breaking the coal or by breaking and washing. From the
experience gained in the use of these typical coking coals, the meth-
ods of treatment of representatives of these types will be apparent.

The annual product of coke required in blast-furnace and other
metallurgical operations during the year 1902 was 25,401,730 net
tons. As it requires an average of 1 .6 net tons of coal to make 1 net
ton of coke, the draft on the coking coal mines for the above year

TREATISE ON COKE 45

was 39,604,007 net tons of coal. The area of coking coals to the
total coal area of the United States has not been accurately deter-
mined, but it is evidently small. As only a very limited proportion
of this coking coal area can be used for coking, without preparation
by crushing, classifying, and washing, it is evident that, with the
present great demand for coke, this small section of pure coking
coal will be exhausted within a not very extended time. At this
time, coke manufacturers have invaded the areas of the second-
class coking coals which require preparatory cleansing, and it is
evident that the preparation of these coals for the manufacture of
good metallurgical coke is now most important.

In the presence of so many varieties of coal-crushing and wash-
ing machines, evidently designed to meet the several wants in the
treatment of the different qualities of coals, there can be no reason-
able excuse for using slaty coals in the manufacture of coke. This
essential requirement of clean coke in metallurgical operations is
still more imperative when it is considered that the slates of the
coal go over into the coke and carry with them the associated
sulphur. In furnace operations, especially when slate in the coke
is silicious, an increased charge of limestone will be required to
eliminate these impurities, and this will make it further necessary
to add to the fuel charge also. Besides all this, there is the danger
of the presence of sulphur in the pig metal produced, if it is designed
for the manufacture of steel. It is therefore evident that the only
safe plan in the manufacture of coke for metallurgical uses is to use
only a pure quality of coal ; but in case this cannot be secured and
a second quality must be used, its cleansing, by crushing and
washing, becomes an absolute necessity.

In America, with its ample areas of the best qualities of coals,
it is only necessary at this time to require clean mining to produce
coal of great purity for manufactures and in the production of
coke. At many of the coal mines in Europe, coal washing of
fuel for manufacturing purposes is coming into very general favor;
but in America, with its superior qualities of coals, it is only neces-
sary to cleanse the secondary or slaty coals in preparation for the
manufacture of coke.

The impurities in these coals consist of shales, iron pyrites,
ferrous sulphide (FeS?), sulphate of lime, argillaceous matter, and
phosphorus. The principal element is sulphur, with its organic
condition and combinations.

Sulphur is found in five principal physical conditions:

1. Pyrites is usually found in lenticular pieces as well as in
balls; occasionally it forms the filling of the stems of the larger
plants of the coal flora. In all these conditions it can be separated
from the coal by a process of crushing or by crushing and washing.

2. Where the sulphur is found in -the strata thinly inter-
leaved in the coal, the process of separation becomes more difficult,

46 TREATISE ON COKE

requiring the coal to be broken into very small sizes, with careful
classification of the different sizes, in preparation for the ultimate
operation in the washer.

3. Occasionally, the sulphur is found in the coal in little disks,
like fish scales ; these present a still more difficult condition in the
process of removing the sulphur, as the sulphur disks are light and
in the fine pulverized condition of the coal many of them are carried
over the edge of the washer pan with the coal. The water used in
washing should not be reused, as it would carry back some of these
sulphur disks, increasing the undesirable element.

4. In the combination of sulphur with lime, as sulphate,
gypsum, usually found in thin plates in the coal, some of it can be
removed in the process of breaking and washing, but all that goes
over to the coke is in a fixed or negative condition as to its action
when used in blast-furnace operations.

5. When sulphur is found in organic combination with the
coal, supposed to be combined with carbon and hydrogen, very
little of it can be removed; it goes over mainly to the coke.

CRUSHING COAL

Advisability of Crushing Coal Before Coking. — In practice, it has
been discovered that breaking the coal that comes from the mine in
large lumps, especially when the percentage of its volatile matter is
small, adds to the value of its coke. The importance of this dis-
integration of the coal before it is charged into the oven will readily
appear when it is understood that in this condition, other things
being equal, the fusing elements assumed to be in the volatile
matter are utilized to the utmost. It has been found that a mixture
of lumps and fine or small coal fuses unevenly in the process of
coking in the oven; the fine coal fusing rapidly, while the lumps
require more time for the coking process to reach the middle of the
lumps. It follows, therefore, that all coals will be benefited for
making a uniform quality of coke and securing the full time in the
oven, by being disintegrated before being charged into the coke
oven, even if they do not require the further process of washing.

In the selection of machinery for disintegrating or washing coal,
or both, it will be wise to consult those experts in these processes
who have made these practical operations special studies. A gen-
eral principle should govern in these matters, to insist on the appli-
cation of the simplest machinery with the largest practicable
automatic service.

Every variety of coal will require special apparatus for its treat-
ment, and the proper apparatus can be determined only by a careful
study of the physical and chemical properties of the coal. All coal
requiring washing should be carefully classified. This will insure
the most efficient removal of slate or other impurities, as it will

TREATISE ON COKE

afford the best condition for their separation in the washer by the
difference in their specific gravities ; the coal of equal size being the
lighter will rise, while the heavier matter, slates or pyrites, will sink
in the pulsing water of the washers. Some coals have their slaty
impurities so mixed with fireclay that they melt in the water in
the washer. Efforts have been made to treat these difficult coals
in the dry way, by passing the classified products through a current
of air, the separation being effected, just as in water, by the differ-
ence in the specific gravities of the coal and its impurities. Other
methods have been tried with indifferent success. If an examina-
tion of the character of a
coal shows that it requires
special and expensive
appliances, with doubtful
results, it will be well for
the coke manufacturer to
avoid attempting to use it.

Bradford Coal Breaker.

For the disintegration of
coals requiring this pre-
paratory process, with the
removal of slate and py-
rites, the Bradford coal
breaker, shown in section
and plan in Fig. 1 (a) and
(b) , will be found well
adapted and economical.
It is simply a drum or cylin-
der of iron parts, having its
lagging perforated to gauge
the size to which it is
desired to reduce the coal.
This is accomplished by
the percussioa of the coal
falling in the interior of the
revolving drum from the
upper to the lower sections.
The length of this fall, or
the diameter of the drum,
is made to meet the

requirements of the coal. If the coal is soft and friable, the diam-
eter is minimum; if the coal is hard and tenacious, the diameter
of the drum is increased accordingly.

The drum is fed with coal at one end and the slate and other
refuse is discharged at the other end ; the pure coal passes through
the meshes in the lagging of the drum and is received into a pit
from which it can be elevated to any desired level.

(b) Plan With Bin Removed
FIG. 1. BRADFORD PATENT COAL BREAKER

48 TREATISE ON COKE

It is worthy of note that this method of disintegration, with
separation of slates and pyrites, also removes bony coal, as the
force of the fall in the drum is regulated to afford just sufficient
concussion to break the purer portions of the coal, leaving the
bony coal unbroken and discharging it with the other impurities.

The Bradford patent coal breaker as put on the market at
present by Messrs. Heyl & Patterson, of Pittsburg, Pennsylvania,
who control and build it, differs very materially from its original
form, which consisted of a cylinder supported on stationary rollers.
In this shape, it was not found very satisfactory, but was operated
long enough to demonstrate the value of the principles involved.
The breaker, as now constructed, has trunnions cast on both heads,
which carry the entire weight. The bearings are protected from
the dust and are provided with thorough lubricating devices, thus
reducing the amount of power consumed to a minimum.

The elevation of the breaker shows the method of supporting
it; also, the driving mechanism. The diameter of the breaker a
varies from 7 feet to 12 feet, depending on the hardness of the
coal — 9 feet diameter being the general size used; the length
varies with the results to be obtained. The heads, with trunnions
and spreaders, are made of cast iron of proper proportions. The
lagging, or mesh, which consists of steel plates perforated with
holes varying from J inch to 2^ inches square, is securely fastened
to the separators. To the plates are bolted cast-iron fingers that
aid in breaking the coal as it falls on them. To one of the heads
is fastened a segment gear that engages in a pinion on the counter-
shaft placed on top of the bents supporting the breaker.

The coal passing into one end of the breaker under the trunnion,
is picked up by longitudinal shelves and discharged, falling on per-
forated plates; that which is of proper size then passes through the
mesh and the larger pieces are picked up by the next shelf and again
thrown down. The coal, in falling from the shelf, has not only the
force derived from its own gravity, but receives a very considerable
additional force from the momentum of the breaker. The fingers
not only aid in the breaking of the coal when it falls on them, but,
being so designed as to form portions of spirals, can be regulated
either to rapidly advance the body of the coal and impurities to
the opposite end of the breaker, or to retard its progress. Fastened
in the opposite head of the breaker from that at which the coal
enters are wings, which discharge the substance that reaches them.

The principle involved in the separation in this machine is that
the slate and sulphur are usually harder than the coal and a fall
sufficient to break the coal will not break them. The bony coal
is usually harder and always very much tougher, and will not
break with the same fall or force as the coal. By varying the
speed of the breaker, the force of the fall can be increased or
decreased; and with the adjustment of the fingers, the impurities
can be retained in the breaker until all the coal is freed from them.

TREATISE ON COKE 49

Pieces of iron, such as miners' wedges, couplings, etc., which
frequently get among the coal and cause breakage in most machines
for this work, will pass through the breaker and be discharged by
the wings at the end without any damage to the machinery. The
speed of the breakers never exceeds 20 revolutions per minute
and they require but 7 horsepower when operated to full capacity.
The capacity of the breaker varies from 300 to 700 tons per day,
according to the mesh, hardness of coal, and amount of impurities
to be removed.

As it is necessary to have a regular supply of coal for the
breakers to secure the best results, a cylinder feeder is used in con-
nection with the breaker. This feeder b is placed under the bin c
and at the end of the breaker a. It has two pockets, which, as it
rotates, are filled and discharged into the chute that leads to the
breaker. It will handle successfully the largest lump or run-of-
mine coal, allowing the bin above it to be completely filled. The
feeder is not only valuable for regulating the supply of coal to the
breaker, but in plants where the coal is handled after leaving
the breaker, it prevents the overloading of the elevators or con-
veyers. The coal is dumped from the tipple d into the bin c\
from there it is fed into the breaker a by the feeder b; from the
breaker, it passes into the bin e, and is then loaded into the larry /.
The breaker is run by the engine g.

The cost of a plant of one 9-foot breaker, such as is illustrated
in Fig. 1, and installing the same ready for operation, exclusive of
boiler, does not exceed $3,000. A plant of this size requires very
little attention and it is unusual for additional help to be employed
other than that required for handling the coal on the tipple.

There are now eight plants comprising twelve breakers in
Western Pennsylvania and three plants in other states. The largest
plant is that of the Rochester and Pittsburg Coal and Iron Company
at Walston, Pennsylvania, which has three breakers with a daily
capacity of 1,200 tons through a 5-inch mesh, and elevators for
lifting coal to a vertical height of 80 feet and discharging it into
a storage bin, as well as a conveyer for removing refuse; the expense
for labor operating this plant does not exceed $2.50 per day.

The Vesta Coal Company, at Lucyville, Pennsylvania, is opera-
ting one 12-foot breaker, with IJ-inch mesh, that has a daily
capacity of 750 tons. This plant, being situated in the fourth
pool, Monongahela river, handles probably as hard a coal as is
coked any place in the country. It does not employ any help
except that necessary for the dumping of coal on tipple.

At the large works of the Cambria Steel Company, Johnstown,
Pennsylvania, this breaker, as shown in Fig. 1, is capable of break-
ing 60 tons per hour. During a continuous run of 17 days at this
plant, with the use of 3,556.7 net tons of coal as it came out of the
Rolling Mill Mine, 35.5 net tons of slates and pyrites were removed
in passing through the breaker, which shows a reduction of these

TREATISE ON COKE

impurities of nearly 1 per cent. Estimating the cost of engineer,
oil, steam, etc., at $40 for these 17 days of trial, the expense of
this work of breaking the coal is about 1^ cents per net ton.

The following is an estimate of the cost of this plant complete
and ready for operating:

Chute and screens in place $ 228 . 00

Bradford breaker, with feeder, hopper, elevator,

conveyers, belts, shafting, and pulleys, in place . 4,722.00

Engine pipes and fittings 1,126. 60

Siphon and strainer 17.25

Foundations, bolts, etc 1 ,729. 51

Lumber. 1,095.89

Labor, masons, carpenters, etc. . .• 2,882. 91

Total $11,802.16

This machine is well adapted for treating coals in which the
sulphur occurs in lenticular pieces or balls of pyrites. It removes
pyrites, slate, and other large impurities, but its value terminates
with this quality of coal. It has its main value in removing these
impurities from steam coals when they are designed for use for
firing boilers, especially in the preparation of coal to be used in
mechanical stokers, as it can be made to reduce the coal to sizes
suitable for these purposes.

STEDMAX'S COAL BREAKER

Stedman's Coal Breaker and Disintegrator. — The Stedman
Foundry and Machine Works, of Aurora, Illinois, presents two
machines for the treatment of coal in preparing it for coking: a
coal-breaking and a coal-disintegrating appliance.

The Stedman coal breaker, Fig. 2, is designed to break the
coal to the size of walnuts or marbles, to be followed by the usual

TREATISE ON COKE

processes of classification and washing to remove the slate and
sulphur before charging the coal into the coke oven. It is appli-
cable to all coals requiring cleansing by crushing and washing.

The Stedman disintegrator, Fig. 3, is a strongly made machine
to pulverize coal to a uniform fineness of cracked wheat or corn
meal. It is designed for use in treating the purer coals that do
not require to be washed. This crushing of coal for coking is
helpful in utilizing the volatile matters, especially in coals inherit-

FIG. 3. STEDMAN'S DISINTEGRATOR

ing small volumes of fusing matters, as it enables the heat of
the oven to be diffused simultaneously through the charge of
coal, quickly fixing and securing the utmost possible fusion of
the coal in the process of coking. The matter of determining
the size to which the coal should be broken by either of these
machines can be determined by the quality and the chemical
composition of the coal. The same consideration will apply to
the preparation of similar coals requiring the additional treatment
of washing. These matters are mainly local and practical, and
the manufacturer of coke will be called on to exercise judgment
in this preparatory treatment of coal from his previous experi-
ence. The evidence of this work will be determined by the work
of the coke oven.

The following statements exhibit the estimated cost and work
of these machines:

52 TREATISE ON COKE

ELEVATOR, CAPACITY 200 TONS, 10 HOURS, SINGLE STRAND

HEAD

1 Head-shaft 2r& inches by 48 inches long

2 Pillow-blocks 2^ inches long.

2 Collars 2/6- inches }. $15 . 20

1 24-in. No. 108 sprocket wheel.'

1 Key

ELEVATOR BOOT

1 12" X 7" cast -iron boot complete with shafts, adjustable

boxes, sprocket wheels, and collars $42.00

Price per foot for No. 108 chain and elevator buckets 3.00

CRUSHING PLANT, CAPACITY 250 TONS DAILY

1 44-inch Class A disintegrator complete $700 . 00

Capacity 200 to 250 tons daily. Power required, 1 horse-
power for every 4 or 5 tons of coal crushed daily. Space
occupied by disintegrator, 9 feet by 6 feet.

2 11" X 18" engines connected at right angles with two 60-

inch bandwheels on the main shaft to drive to the two
pulleys on the disintegrator. Engines' speed, 150 revolu-
tions per minute, developing from 75 to 80 horsepower.
Engines are complete with two 60" X 12" pulleys on the
main shaft, automatic stop-governor, throttle valve,
spanner wrenches, cylinder, lubricator, oil cups, cylinder
cocks, anchor bolts, and plates, and blueprint drawings
for foundation. Price complete as described, f. o. b.
cars, Aurora 738 . 00

1 4-inch tubular boiler, 62 inches diameter, 16 feet long, 90
horsepower, complete with chimney and breeching, guy
rods, fire-front, grate bars, bearing bars, back stand, back
plate, soot doors and frame, anchor bars, tie-rods, safety
valve and weight, check- valve, stop-valve, and blow-off
valve, whistle, water and steam gauge, feedpipe and
connections. In fact, boiler with all settings and trim-
mings. Price delivered on cars, Aurora 895.00

1 Duplex pump to supply boiler with water and all fittings

and connections to connect to boiler 175. 00

COST OF MACHINERY AS DESCRIBED

1 44-inch disintegrator as described $700 . 00

2 11" X 18" double engines, 75 to 80 horsepower 738.00

1 4-inch tubular boiler, 62 inches diameter, 16 feet long, 90

horsepower 895. 00

1 Duplex pump as described 175 . 00

Total cost $2,508 . 00

ELEVATOR, 250 TO 275 TONS CAPACITY IN 10 HOURS,
DOUBLE STRAND

HEAD

1 Head-shaft 2^ inches by 6 feet long

2 2re-inch pillow-blocks

2 2-iVinch set collars I $21 . 50

2 24-inch No. 83 sprocket wheels

2 Keys

TREATISE ON COKE 53

ELEVATOR BOOT

1 14" X 1" cast-iron boot complete with shaft, 2 sprocket

wheels, adjustable bearings and collars $47.00

Price per foot for No. 83 double chain and buckets 3.65

CRUSHING PLANT, CAPACITY 350 TO 400 TONS DAILY

1 50-inch coal disintegrator complete $ 900 00

Capacity 3"50 to 400 tons of crushed coal daily. Power
required, 1 horsepower for every 4 or 5 tons crushed coal
in 10 hours. Space occupied by disintegrator, 10 feet by
8 feet; weight complete, 17,000 pounds.

2 13" X 20" engines complete, connected at right angles with

two band wheels 78 inches diameter, 16-inch face on the
main shaft to drive the two pulleys on the disintegrator.
Engines speed at 140 revolutions per minute, developing
from 110 to 120 horsepower; engines complete with band-
wheels, automatic stop-governor, throttle valve, spanner
wrenches, cylinder cocks, lubricator, oil cups, anchor
bolts, and plates. Blueprint drawings for foundation
furnished. Price complete, f. o. b. cars, Aurora 1,000.00

2 4-inch tubular boilers, 130 horsepower, 54 inches diameter,
14 feet long, complete with all necessary fittings and
trimmings, consisting of fire-front, grate bars, bearing
bars, back plate, soot door and frame, check, blow-off
and stop-valve whistle, steam gauge, gauge-cocks, water
gauge, chimney and breeching, guy rods, safety valve and
weight. All pipe connections between engines and boilers
are extra. Price complete, f. o. b. cars, Aurora 1,275.00

1 Duplex pump to supply boilers with water and pipes and

fittings for same f ...... 1 50 . 00

SUMMARY

1 50-inch disintegrator complete as described $ 900 . 00

2 13" X 20" engines as described 1,000. 00

2 Boilers, 130 horsepower, 54 inches by 14 feet 1,275.00

1 Duplex pump to supply boiler with water 150. 00

Total $3,325.00

ELEVATOR, 350 TO 400 TONS CAPACITY, 10 HOURS
DOUBLE STRAND

HEAD

1 Head-shaft 2ff inches diameter, 5 feet 6 inches long
3 Pillow-blocks 2yf inches diameter

2 Set collars 2ff inches diameter

2 25-inch diameter No. 108 sprocket wheels

2 Keys for wheels

$30.00

ELEVATOR BOOT

1 18" X 18" cast-iron boot complete with shaft, two No. 108

sprocket wheels, adjustable bearings and collars $60.00

Cost of elevator chain and buckets per running foot 5.00

ESTIMATE

1 60-inch class A coal disintegrator, complete with fly-
wheels, pulleys, etc. Capacity, 500 tons in 10 hours
and upwards. Weight, 18,000 pounds $1,000.00

54 TREATISE ON COKE

2 14" X 20" engines of the Houston, Stan wood & Gamble
pattern, coupled at right angles with two band wheels
84 inches diameter, 16-inch face to drive the belts
running direct to disintegrator, engines run at 130
revolutions per minute, developing about 125 to 135
horsepower. Engines are complete with governor, two
bandwheels, throttle valve, spanner wrenches, automatic
sight-feed lubricator, oil cups, and cylinder cocks. All
pipe fittings and connections are extra. Price of engine
as described $1,064.00

2 Tubular boilers 60 inches diameter, 10 feet long; rated at
160 horsepower, complete with all necessary trimmings,
consisting of fire-front, grate bars, bearing bars, back
plate, soot door and frame, check, blow-off and stop-
valve, whistle, steam gauge, gauge-cocks, water gauge,
chimney and breeching, guy rods, safety valve and
weight All pipes and connections between engines and
boilers are extra. Price complete, f. o. b. cars, Aurora 1,650.00

1 Duplex pump to supply boiler with water and pipe and

fittings for same 1 75 . 00

SUMMARY

1 60-inch disintegrator complete as described $1,000 .00

2 14" X 20" engines as described 1,064 00

2 Boilers 160 horsepower as described 1,650. 00

1 Pump to feed boiler 175.00

Total $3,889.00

ELEVATOR, 550 TONS CAPACITY

HEAD

1 Head-shaft 3i^ inches diameter, 6 feet long

3 Pillow-blocks 3r^ inches diameter . .

2 Collars 3-^ inches diameter > $41 .00

2 30-inch No. 108 sprocket wheels

2 Keys

ELEVATOR BOOT

1 Cast-iron boot for 24" X 10" buckets complete with shaft,

two sprocket wheels, adjustable bearings and collars . . . $75 . 00
Price per foot for No. 108 double elevator chain and

buckets , 6. 50

Link-Belt Coal Breaker. — The coal breaker, Fig. 4, is made by
the Link-Belt Machinery Company, Chicago, Illinois.

The size and spacing of the teeth are made to suit the size to
which the coal is to be broken, by which is meant the size of the
largest pieces. In breaking to this size a large part will be broken
finer. In general, it may be expected that the smaller the diameter
of the roll the greater will be the percentage of fine, so that, if it is
desired to break to a certain size without reducing much to smaller
size, large diameters of rolls should be selected or a series of rolls
put in, breaking first coarse, then finer, with screens between.

These rolls are made in the following sizes:

TREATISE ON COKE

Size of Rolls

Shipping
Weight

Approxi-
mate
Capacity

Speed
Revolu-
tions

Horse-
power

Maximum Size
of Piece That
Will Enter

Diameter

Length

Pounds

Tons
per Hour

per

Minute

Required

Inches

3,500

225

10X15

5,550

200

10X20

7,000

160

14X20

7,800

160

14X24

10,000

125

16X24

12,000

125

16X30

13,000

100

18X30

FIG. 4. LINK-BELT COAL BREAKER

FIG. 5. LINK-BELT COAL CRUSHER

Fig. 5 shows a crusher made by this company and having one
smooth and one corrugated roll. It is used for special service in
coal washing.

TREATISE ON COKE

Fig. 6 shows a disintegrator made by the same company and
used for fine crushing of coal. It is made in two sizes: 36-inch
diameter, 20-inch face; 48-inch diameter, 24-inch face.

COAL WASHING

Coal washing is entirely a mechanical process, and water is the
main element employed in separating the coal from its impurities.
The chief requirement in the coal-washing process is the reduction

FIG. 6. LINK-BELT DISINTEGRATOR

of the sulphur in its several conditions and of the ash, so that the
coke made from this washed coal shall contain under 1 per cent.
of sulphur, with ash from 6 to 10 per cent. This operation for the
successful cleansing of the coal depends on the enabling law of
the difference of the specific gravities of the coal and its several
impurities. The average specific gravities of these are:

SPECIFIC GRAVITY

Water 1 . 00

Coal 1 . 25 to 1 . 50

Bone coal 1.45 to 1.80

Slate 2.25 to 2. 50

Coal or slate with pyrites 3.20 to 3.60

Pyrites 5.00 to 5. 20

In practice, a great variety of the combinations of these elements
is found in the coal, requiring in its preparation for the washer
and in the washing process special treatment for each variety.

As has been noted, the coal requires a preparation for washing
by crushing or breaking and by classifying or sizing. Whether the
coalis to be used in the manufacture of coke or for any other
purpose, the sizing of the coal in its preparation for washing is
indispensable. It has been determined that, as a general rule, the

TREATISE ON COKE

smaller the ratio of reduction of the pieces of the coal, the more
complete is the process of separation. Very much, therefore, of
the success of this operation depends on the proportioning of the
sizes of the meshes in the classifying screens, especially for the
separating of the lesser impurities in the coal under the grosser
iron pyrites, which are the most readily removed.

It may be noted here that the best machinery for accurate
separation or cleansing of the coal is usually the most costly,
involving the greater expense in the first cost of the plant, but
securing in its work the best results. As will be seen hereafter, in
the preparation of the washed coal for charging into the coke
oven, the coal-storage arrangement to remove some of the water
or moisture from the coal is a secondary necessity.

TROUGH WASHERS

Simple Trough Washer. — During the close of the past century,
especially in continental Europe, very much attention was given
to mechanical appliances for washing coal. The most primitive of
these consisted in a long wooden trough, divided by low cross-
sectional dams at intervals along its course. The inclination of
this sluice was usually made to give sufficient force to the water
passing through it to separate the coal from the slate, the slate
remaining in the upper recesses of the dams, while the coal was

FIG. 7. PLAN AND SECTION OF TROUGH WASHER

t, trough; s, dams; a, screen; h, hopper for delivery of coal; p, stand pipe for applying
water; c,c' , cars for washed coal and slates; this wooden trough is usually 30 to 100 feet long,
2 to'4 feet wide, and 12 to 15 inches deep.

carried over, screened, and delivered into a car or other receptacle
at the lower end of the sluice. The slate was removed at stated
intervals by an attendant with a rake. The prepared coal and
the water for its cleansing were received together at the upper end
of the trough. The plan and section, Fig. 7, will make this old-
time washer and its operations easily understood.

TREATISE ON COKE

TREATISE ON COKE 59

Elliott Trough Washer. — An improvement has been made on
this trough washer, which adds very much to its efficiency, econo-
mizing labor and water in the process of washing. The following
plan, section, and description, Fig. 8, are taken from The Colliery
Guardian, London, of November 16, 1894. This machine was
designed on the lines of the old trough washer, which has long been
a favorite with many colliery engineers on account of its sim-
plicity and its efficiency when in the hands of an intelligent, trust-
worthy attendant. In addition to the difficulty of always obtaining
the necessary skill and attention, there was also in the old troughs
the necessity of changing the flow of coal and water into a second
trough while the dirt was being washed off and removed from the
first, when the stops had become charged with it; for if this was
not done at the proper time some of the dirt became mixed with the
coal and the result was not satisfactory. The Elliott washer, as
shown in Fig. 8, is claimed to be automatic in its action, and retains
all the advantages of economy and efficiency of the old trough
without any of its disadvantages; it is, moreover, independent of
the skill or attention of the attendant, the operation of washing
proceeding without interruption as long as is required, the
coal being delivered at one end of the trough, with the water
and the dirt at the opposite end.

The washer is constructed with a wrought-iron or steel trough
about 18 inches wide, having sloping sides, being widest apart at
the top, and narrowest at the bottom. At each end of this trough
is fixed a sprocket wheel, on which rides a chain, attached to which,
at suitable distances and at right angles to it, are scrapers that
correspond to the inside shape of the trough. The scrapers form
movable stops, or dams, that are slowly moved by the chain along
the trough in the opposite direction to the way the water runs.
The trough is fixed at a suitable inclination, and the coal is admitted
at the center of its length and the water at its highest end or there-
abouts, and as it runs to the lowest end it carries with it the coal,
which is lighter than the dirt; the dirt settles in the scrapers and
is conveyed by them against the stream of water and delivered at
the opposite end to that at which the coal escapes. The speed of
the scrapers and quantity of water are regulated to suit the material
washed. The water is circulated and used continuously, so that
the waste is only that which is carried away by the dirt and coal
after drainage. A centrifugal or other pump is used for elevating
the water to the washer. The arrangement for draining the water
from the coal is such that there is no waste of coal or pollution of
streams, etc. A 1-inch pipe will keep good the supply of water
for each trough, or 100 tons of coal washed per day. This washer
has been introduced by the Hardy Patent Pick Company, Limited,
of Sheffield, England.

This class of coal washer requires large quantities of water, and
its work is somewhat expensive and imperfect.

(a) Trough Raised

FIG. 9. SCAIFE TROUGH WASHER

TREATISE ON COKE • 61

The Scaife trough washer, Fig. 9 (a) and (6), consists of an
inclined trough a of semicircular cross-section, 2 feet in diameter
and 24 feet long, provided at intervals with riffles. Lengthwise
of the trough is the shaft b to which are attached the stirrers c.
The shaft is given a reciprocating motion by means of an arm in
its center, worked by a connecting-rod attached to the flanged
driving pulley d. The empty trough, which is hinged to the frame
on one side, is partly held in position by the adjustable counter-
balance weights e on the arms / attached to the trough. A tongue
on the operating lever g passes through an eye on the trough and
firmly holds it in place.

Coal and water are fed into the upper end of the trough a. The
combined action of the flowing water and stirrers causes the slate
and other impurities to settle at. the bottom of the trough, where
they are caught by the riffles, while the clean coal passes over the
top and out at the lower end. When the spaces between the riffles
are filled with impurities, the feeding of coal is stopped, or tempo-
rarily turned into an adjacent washer, and all the remaining coal is
washed over the riffles. The operating lever g is moved a few
inches to the right, which draws the steel tongue out of the eye and
releases the trough, and allows the latter to drop and dump the
refuse. The trough is returned to its original position by moving
the operating lever still farther to the right, which engages a clutch
and causes the chain h to be wound up and lift the trough; the
weight i keeps the chain taut. As soon as the trough is raised, the
lever should be drawn quickly to the left until it reaches its original
position. This movement releases the clutch and locks the tongue
in the supporting eye of the trough. The washing is then recom-
menced. Where the washer is properly erected and operated,
the dumping and raising will occupy less than a minute. This
washer has no screen to wear and be replaced. The principal
wearing parts are the stirrers, which are inexpensive and can, if
desired, be made anywhere. The water may be used over and
over again. The slope or fall given to the trough depends on the
size of the coal and nature of the impurities; the larger the coal,
the greater should be the slope and the quantity of water.

JIGS

Principle of the Jig. — To economize water and separate the
impurities from the coal in a more complete and economical manner,
an improved class of washing machines, called jigs, has been intro-
duced. These have, in a great measure, displaced the older meth-
ods. The several classes of the broken coal previously sized are
delivered into separate receptacles, or jigs, in a water bath, and
the separation of the coal from the impurities is accomplished by
imparting a pulsing motion to each receptacle, or jig, of such speed
as to secure the best results. This pulsing motion in the modern

TREATISE ON COKE

improved machines forces the lightest matter — the coal — to the
surface of the water, carrying it forwards and over the delivering

edge of the jig into a car or
other means of conveyance to
move it to points where it is to
be used. The heavier, or im-
pure, matters sink under the coal
in this pulsing movement and
are dropped into special receiv-
ers under the washer for ulti-
mate disposition.

The force of the upward
pulsing current is regulated so
as to meet the requirements of
the several varieties of coals,
in the process of removing their
impurities. If this current is
too strong it will disarrange the
classification of the coal; if too

FIG

HARTZ JIG

p, plunger; /, feeder, prepared coal;
water supply; s, water chamber; o, coal cham-
her; a, slate delivery; b, clean-coal discharge;

f, sludge discharge.

Capacity, about 150 tons per day. Cost,

about 5 cents per ton.

it will fail to separate the
larger pieces of coal. It is also
important that the force of the
upward pulsing current be uni-
form in its action through the mass of coal in the washer chamber
of the apparatus, otherwise imperfect work will ensue.

Mr. H. Rittinger, who has given the mechanical separation of
materials considerable study,
has, from practical tests, de-
duced the following formula:
The velocity of the current
in feet per second is equal to
1.28 ^D(d—l), in which d is
the density of the material,
and D the diameter of the
meshes in the screen, or prac-
tically the diameter of the
pieces to be operated on.

The Hartz Jig.— Fig. 10

illustrates the general princi-
ples of the operations of
this class of coal-washing
machines.

FIG. 11. LUHRIG FELDSPAR JIG

The Liihrig jig, Figs. 1 1 and
12, illustrates, in a brief way,
the essential elements of coal washing. Fig. 11 shows the Liihrig
feldspar jig, which is used exclusively for the treatment of fine coal.

TREATISE ON COKE

Fig. 12 shows the Liihrig nut-coal jig as arranged with its machinery
for automatically removing the refuse.

Berard's coal-washing machine, Fig. 13, was introduced in
London in 1851, and in Paris in 1855. It was used by the Kemble
Coal and Iron Company in the Broad Top region, Pennsylvania,
for a few years beginning in 1873.

The coal to be cleaned is dumped from the railroad car a into
the hopper b by a side door over an iron chute; thence, it is diffused
on the separator c, which is
kept in agitation by the cam d.
The lumps that will not pass
through the 3-inch square
openings in c roll down to the
screen platform e, where they
are broken by a workman
with a maul and, falling
through the grating, pass to
the rolls /. The smaller lumps
pass through the 3-inch
meshes in the agitator screen
c, when they are further
divided by a screen under-
neath c. The portions of
the coal that will not pass
through the J-inch holes in
the latter screen pass directly
to the rolls /, while the very
fine portion is carried under
the rolls, down the chute g,
into the receiver h. The
rolls / have teeth, or spurs,
set all over their circumfer-
ence, each being about J inch
square by ^ inch high. Their arrangement is such that the spurs
of one roll mesh into those of the other. One of the crushing
rolls has its pillow-blocks set with a rubber-ball spring, so as to
admit a small horizontal movement, to prevent the breaking of
the teeth of the rolls by the passage of hard slates or pyrites.

After passing the rolls, the crushed coal falls into the receiver h,
whence it is elevated by the chain of buckets i and delivered into
the chutes /, through which it is carried into the separating pans k,
which are made of cast iron, with a copper plate on top of the
grating, forming the bottom of the iron pan; the copper plate is
perforated with J-inch holes, set close together. The pans are
supplied with water conveyed by troughs, through which the coal
is also carried. The action of the piston /, which moves with quick,
short strokes (120 per minute), forces the water through the coal

FIG. 12. LttHRic NUT-COAL JIG

TREATISE ON COKE

TREATISE ON COKE 65

and slate in rapid pulsations, lifting the pure coal upwards and
onwards with the movements of the water until it is carried over
the side of the pan at m, and thence over a grated chute into the
car n, on the track in front of the washer.

The impurities, being heavier than coal, sink to the bottom of
the pan and are carried to its front interior angle, whence they are
discharged by a valve o into the receiver p, from which they can be
removed by a sliding bottom q. The movement of the mass of
coal in the pan is about 20 inches per minute, giving a continuous
overflow of washed coal into the receiving cars below. This flow
can be regulated by raising or lowering the front side of the wash
pan at m.

The main portion of the water in the washed coal is drained
from it by a fine copper-wire screen on a chute, immediately under
the discharge from the wash pan at m. This water, charged with
the very fine coal and dust, passes through r, and is conveyed by
a trough s into a large tank alongside the washer, where the fine
coal is permitted to settle, and from which it is shoveled into the
receiving cars along with the coarser coal and all charged into
the coke ovens.

The Stutz improved coal washer, Fig. 14 (a) and (b), has been
tested in practice during many years. It is simple in its construc-
tion, yet efficient in its operations, requiring a small force in working
it. It was designed by S. Stutz, mining and mechanical engineer,
of Pittsburg, Pennsylvania, who has followed up its workings,
adding from time to time such improvements as appeared neces-
sary to make its processes more complete.

Fig. 14 (a) is a longitudinal vertical section, and Fig. 14 (b) a
vertical cross-section at the lines XX and Z Z of Fig. 14 (a).

In this figure, a, a are cast-iron brackets supporting a rectan-
gular box divided into chambers b, c, and d, constituting two
complete machines. Arranged within the chamber b is a screen
or sieve e, while the chamber c contains the piston, or plunger, /
with its mechanism to reciprocate vertically. The slate chamber d
communicates with the separating or washing chamber b through
an opening g, governed by a suitable valve h.

A trough, or chute, i provided with a screen / communicates
with the separating chamber b to receive the washed coal as it
passes over the bridge k. Beneath the slate chamber d and the
separating chamber b an auxiliary receiver / is arranged, which
communicates with both chambers by means of the openings m'
and m,m, for the purpose of providing means to collect the sedi-
ment that passes through the meshes of the sieve e during the
operation of the machine, and to effect its escape without wasting
the water in the washing chamber 6, thus making the operation of
the washer continuous. Before letting out the fine sediment, the
openings m, m are closed by the gates n, n, and the communication

TREATISE ON COKE 67

with the washing chamber b is shut off. No water is wasted. The
receiver also collects the coarse impurities from the slate chamber d ;
both kinds, coarse and fine, may be let to the outside of the machine
by the levers o, o' .

The piston, or plunger, / is provided with large openings p, p,
in its bottom; they are governed by floating valves q underneath,
kept in proper position by guides r, r. With the improved plunger,
the necessary volume of water is let into the machine from above
by means of the pipe s, thus filling up more easily the entire space
when the piston is moving upwards. Movement is imparted to
the latter from the shaft t by means of the cam u, yoke v, and
rod w. Coal to be washed is supplied to the screen e through a
hopper x. The separation of the coal from its impurities is accom-
plished in the usual way. The pulsations of the water by the
movements of the plunger lift the lighter coal upwards, while the
slates, pyrites, etc. sink to the bottom. The stroke of the plunger
can be varied to meet the wants of the different sizes of coal.

The Stutz improved coal-jigging and washing machine, Fig. 15,
has a vertical reciprocating piston or plunger directly underneath
the stationary sieve or screen; (a) is a longitudinal vertical section
through the center of the jigger; (b) is a section taken at line X X
of the top view (c), and a front elevation of two machines combined
together.

In the figure, a, a represent cast-iron brackets supporting the
separating box b, arranged within which is the screen or sieve e,
with the piston, or plunger, / below, and the mechanism whereby
the latter is caused to reciprocate vertically above. The slate
chamber d communicates with the washing chamber b through the
opening g, governed by the valve h. A trough or channel i also
communicates with the washing chamber b and is designed to
receive the washed coal as it comes over the delivery bridge k. An
auxiliary receiver / is arranged beneath the chamber 6, and com-
municates with the latter by means of openings m, m governed
by gates n, n. The receiver / also communicates with the slate
chamber d, through the opening m', for the passage of the coarse
impurities. The outlet gate, or door, y of the auxiliary receiver
is connected to bell-crank levers o, o by links. Movement is
imparted to piston / by means of eccentrics u, u keyed upon the
driving shaft t, and yokes v, v connected to rods z, z. Coal is fed
upon the screen e from the hopper x, while the supply pipe s fur-
nishes the necessary volume of water for the operation.

The purpose of the auxiliary receiver / is to provide means for
collecting the fine sulphur and slate pieces that pass through the
meshes of the sieve e during the working of the machine, and to
effect the escape of this fine sediment without wasting the water
inside the washing chamber b, thus making the operation of the
jigger absolutely continuous.

TREATISE ON COKE

By means of the improved and special-shaped piston / acting
at each up stroke like a wedge behind the material on the screen,
the different layers of the separated substances — coal and impuri-

ties—-are readily and uniformly advanced toward the delivery
openings, while below the screen the rilling up, or choking, by the
fine sediment passing through its meshes, is also prevented.

TREATISE ON COKE

The cost of these coal-washing machines, for cleaning 300, 400,
and 600 tons per day, will depend mainly on location, quality of
coal to be treated, and the character of its impurities. Mr. Stutz
has furnished estimates for the treatment of the above outputs
per day of 10 hours at $11,000, $13,000, and $16,000, respectively.
This estimate includes the necessary power, water, and building.
It does not, however, embrace the machine for disintegrating
the coal in the preparatory process; the cost of this will be found
under the head of coal crushers or disintegrators. The cost of
washing is given at 2 cents per ton for the work of washing alone.

FIG. 16. STEIN'S STANDARD COARSE CORN-COAL JIG, STYLE C

The interest on investment of plant and the wear and repair of
machinery must be added to show the total cost of cleaning the
coal in this machine.

WALTER M. STEIN'S WASHERS

Stein Jigs. — Figs. 16, 17, and 18 show jigs, Stein standard,
while Fig. 19 shows the general arrangement of a coal-washing
plant designed by Mr. Walter M. Stein, of Philadelphia, for the
New Glasgow Iron, Coal, and Railroad Company, of Nova Scotia.

TREATISE ON COKE

The coal from the various mines arrives on the railroad tracks
olf a2 and is dumped into the pits 6lf 62 underneath, a different kind
in each pit. From these pits, the coal is taken, by means of bucket
elevators clt c2, to the shaking screen d. This shaking screen has
a double eccentric motion, imitating hand screening as much as
possible. The mesh of the screen plate is | inch. The material
too large to pass through the perforations drops into the crusher

FIG. 17. STEIN'S JIG FOR COARSE SIZES, STYLE G STEIN'S JIG FOR FINE SIZES, STYLE H

WOOD OR IRON TANKS

rolls elt e2, and is again taken, after the crushing, to the shaking
screen d by means of the bucket elevator /. The coal passing
through the shaking screen d is taken by means of the bucket
elevator g to the separating screen drum h, which separates it into
three sizes — 0 to J inch, J to J inch, and J to f inch.

The different sizes are carried by means of chutes to the various
jigs j\ to /8. These are all two-compartment feldspar jigs, arranged
with variable stroke. Each screen compartment is 28 inches wide
and 49 inches long, so that the coal must travel a distance of over
8 feet while being washed. The washed coal flows in gutters to
the large elevator boot &2, and is elevated from there to the top of
the storage tower by means of the perforated bucket elevator /2,
which discharges on the distributing conveyer m, which carries it
into the various compartments n of the large storage tower. The
two jigs shown in dotted lines, the elevator boot klt and the eleva-
tor /!, are arranged to be put in if the plant requires enlargement.
The slate from jigs j\ to /3 is discharged into elevator boot qlt and
is taken from there by means of a perforated bucket elevator rv
and dumped into railroad cars ready to be taken to a convenient
dumping place. The centrifugal pump / distributes the water,
which, after being used, always returns to the pump and is used
over again. There is no loss in this respect except that absorbed
by the coal, and enough fresh water must be added to make up
for this, u is the steam engine of 100 horsepower to drive the
entire plant.

17303— in

FIG. 19. COAL-WASHING PLANT OF NEW GLASGOW

-Sect/on £-f
v, COAL, AND RAILROAD COMPANY, OF NOVA SCOTIA

TREATLSE ON COKE

All the elevators are of special construction and have very
large buckets, automatic feed, etc., and are run at a slow speed.

The entire plant works automatically, requiring only three men
to operate it. The coal before washing contains from 17 to 35 per
cent, of ash, besides about 2^ to 3 per cent, of sulphur; the washed
coal contains in the average 10 per cent, of ash or 1 per cent, more
than the fixed ash, 9 per cent. , of the coal. This is a remarkably good
showing, and is seldom equaled at any washing plant in existence.
The fixed ash cannot be reduced by any method. Coming within
2 per cent, of the fixed ash is ordinarily considered excellent work.
The sulphur is reduced, by washing, from 2J to 3 per cent, down
to 1.35 per cent., that still left being the organic sulphur and that
in combination with alumina or lime.

Jigs yt to ;5 were in the original plant ; /6 to /8 were added when
the additional retort coke ovens were built. The total capacity
of the plant is now 300 tons of coal in 10 hours.

FIG. 18. STEIN'S FINE CORN-COAL JIG, STYLE A, Two COMPARTMENTS, >
AUTOMATIC SLATE VALVE

The Diescher coal washer, Fig. 20, may be constructed with one
box or with a number of boxes connecting with each other and
worked by the same shaft. The boxes may either have outlets, as
shown in (d) and on plan (a), with an elevator for carrying away
the slate and other deleterious materials, or, where the boxes are
fixed on elevated ground, they may have pyramidal receptacles

TREATISE ON COKE

into which such material falls and is discharged at intervals by its
own gravity through a valve operated by a lever.

The modus operandi of the washer is as follows: The coal is
dumped from the back upon the screen shown in section in views
(c) and (d) ; the water is conveyed to the washer by a 3-inch pipe
entering into a cast-iron box fixed at the back (a) ; this box runs
along the back of the washer below the screen and delivers the
water through four 2-inch holes cut out of the washer side (a) and
(c). The action of the plunger forces the water through the screen,

(a) Plan (6) £nrf Elevation (c) Longitudinal Section (d) Transverse Section
FIG. 20. DIESCHER COAL WASHER

agitating the coal and carrying the cleaned coal over the wooden
ledge, shown to the left and a little above the screen, into a trough
that conveys it into bins; the slate and other heavy and delete-
rious materials, by force of their greater specific gravity, fall to
the screen and escape, through the valve shown, into the discharge
pipe and elevator, or into the box previously referred to.

The washer is constructed as shown in the figure, having two
cast-iron stanchions of H section footed out at the bottom as shown.
The upper part of the stanchion has 9-inch web with 4-inch flanges,
by about f -inch metal. The stanchions are connected together on
top by means of two girders of similar section but arch-backed,

TREATISE ON COKE

having the central part of top flange level and dovetailed to receive
the bearing for the main shaft. The stanchions are kept rigid by
means of two l}-inch wrought-iron tie-bolts and distance pieces
of pipe [see top of stanchion in view (d)], and the girders are bolted
to the ends of the stanchion by four wrought-iron bolts at each end.
The body of the washer is composed of 4-inch, white-pine tim-
bers of the widths shown, planed, tongued, and grooved. The side
timbers project beyond the stanchions, as shown in views (a) and
(c), the ends being let into same and further secured by an angle
plate 4 inches by 4 inches (Fig. 21). It will be noticed, by reference
to Fig. 20 (c), that only one end plate is shown. This is on account
of there being a series of connected boxes in a line, the water com-
municating from one box to the other. The partitions of the boxes

t^i

FIG. 21. DOUBLE DIESCHER WASHER

are also of 4-inch timbers reaching down to the angle of box as
shown by Fig. 20 (c). Between the partitions and end, it will be
noticed, there is a space 8 inches wide right under the stanchions
(<;) ; this is the equilibrium chamber, and is provided to keep the
water level and prevent a vacuum being formed. Within the
partition, there is a lining that can easily be renewed and serves to
confine the water between the plunger and the screen. Above the
plunger, an angle-iron frame 4 inches by 4 inches by ^ inch is fixed
as shown in views (c) and (d), upon which the wooden frame to
which the screen is connected rests; this angle iron, together with
the screen, is not fixed perfectly level, but is inclined 1 inch toward
the slate valve to facilitate the discharge of the coal and slate
through their respective openings.

TREATISE ON COKE

The plunger is of cast iron, }-inch metal, 5 feet long by 4 feet
3 inches wide, with four buckled surfaces, as shown in views (a), (c),
and (d), in the center of each of which is a small hole to allow the
discharge into the lower chamber of any fine material that may fall
through the screen. The plungers are suspended by two rods of
suitable size, as shown in views (a), (c), and (d), which are secured
to plunger casting by means of collars and nuts, the casting being
specially thickened for the purpose, view (c). The suspension rods
connect with a cross-bar, as shown by view (c), and are shielded
from the coal by two castings, view (d), having openings 4f inches
by 5 inches by 7 inches deep. These castings are connected to the
washer by lagscrews. The plunger has a stroke according to
material operated upon, ranging from 1J inches to 2 inches, the

smaller stroke being
most suitable for
fine material. The
3-inch cross-shaft is
suspended from ec-
centric or main dri-
ving shaft by means
of two cast-iron ec-
centric yokes, as
shown by views (c)
and (d} ; the yokes
are steadied by a
rod, as shown in (d).
The eccentric or
main shaft is 3J
inches in diameter
and turns in bronze
bearings, resting on
the girders previ-
ously referred to , and

is generally driven by a 32-inch pulley, making 70 to 80 revolutions
per minute, according to the stroke of plunger and the material
operated upon. Where there are several boxes, the plungers rise
and fall alternately, thereby balancing each other, and keeping
the water beneath them in equilibrium. The screens of the boxes
are invariably 4 feet square, composed of a rigid wrought-iron frame
carrying wires of spring brass, which are placed parallel in the direc-
tion of the discharge, having a space between of about -fa inch.
These wires are fastened to the frame by means of copper wires and
all the joints are protected by solder. It will readily be seen that
this arrangement secures a strong, rigid, and durable screen that
allows free passage to the water and to the finest pyrites only..

The slate valve is fixed in the position shown in view (d) ; the
body of the valve has an opening on both sides, 6 inches by 2 inches,
the area of which can be modified at will by means of the movable

FIG. 22. SINGLE DIESCHER WASHER

TREATISE ON COKE 75

valve within, which is operated by a hand wheel and screw. The
size of the discharge pipe, view (d), varies with the kind of material
operated upon. At the bottom of washer, a casting having a
valve in the center for the discharge of the fine pyrites or of the
water when necessary is secured as shown in views (c) and (d).
Access is provided to the underside of the plunger by means of a
circular manhole, about 14 inches in diameter, having a cast-iron
arched door and frame.

The correctness of the principles involved in the construction of
the Diescher washer is noticeable in several ways. One of its good
points is that the position of the plunger is directly under the screen,
which produces a uniform and energetic action of the water and an
equal operation all over the screen surface, whereas, when the
plunger is at the back, an unequal action of the water is produced
on the screen, the effect of which is sometimes only partially
obviated in other machines by means of aprons and scrapers.
Another advantage of this machine is that the water enters the
upper chamber between the screen and the plunger; the result of
this is, as has been found in practice, that no valves are necessary
in the plunger, although these are put in when especially desired.

The washing capacity of a single box varies, according to cir-
cumstances, from 75 tons of coal up to 200 tons in 10 hours, accord-
ing to the amount of dirt and pyrites mixed with it. The cost of
washing coal with the Diescher jig varies with the size of the plant
and numerous other conditions. One man can attend to several
boxes as easily as to a single-box washer. Even in the most unfavor-
able circumstances, the cost of washing the coal will be only a
small fraction of 1 cent, per bushel. In some cases, the cost is less
than -TO cent per bushel.

The Diescher machines have been in practical use for 20 years,
and are now to be found in all parts of the United States and even
in Mexico. Their reputation for simplicity, durability, great capa-
city, and for excellence and economy of the washed coal makes
them very popular and in constantly increasing demand. They are
manufactured by the Scaife Foundry and Machine Company,
Limited, of Pittsburg, Pennsylvania.

BROOKWOOD, ALABAMA, WASHERY

The coal-washing plant at Brookwood, Alabama, Figs. 23 and
24, was designed by Mr. Walter M. Stein, of Philadelphia, for the
Standard Coal Company. The following description is by Mr.
Rudolph Boericke, superintendent, and was written in response to
a letter of inquiry addressed to Mr. Fred M. Jackson, secretary
and treasurer of the company:

"The coal is drawn up the mine slope, by wire-rope haulage, to
the top of a wooden trestle 50 feet high, where it is dumped into

TREATISE ON COKE 77

a storage bin c. It passes first over a double-table shaking screen e,
which divides it into three sizes. The top screen is of 1^-inch mesh
and the other of f-inch mesh. The largest size, comprising nut and
lump, passes over two picking bands / and g, 73 and 68 feet long,
respectively, where it is hand-picked by boys, and then over another
single shaking screen h, of 3-inch mesh, which takes out the nut,
which falls into a bin x and is carried by a chute to the cars.
The remaining lump is delivered to the lump loader i, which con-
sists of a chain of buckets, or pans, moving on iron ways and in
operation is exactly the reverse of an elevator — instead of raising
the coal it lowers it into the car. The lower end swings on chains
and can be adjusted to any height of car, or be raised clear of the
train while the cars are being shifted.

"To return to the coal that passes through the first or 1^-inch
mesh shaking screen e. That part of it that is too small for nut,
yet too large for washing purposes, that is, that which passes over
the f-inch mesh, falls directly to the crusher /, where it is crushed
and returned to the shaking screen. The crushed coal and all the
fine coal from the mine, passing through the f-inch mesh screen, is
sized in a large, double, revolving drum / into three sizes, each
size being washed through gutters to jigs k adapted and adjusted
for it. There are eleven double-compartment plunger jigs in all,
each capable of handling from 5 to 7 tons per hour. In these jigs,
the raw coal enters at one end, and moves across both compartments
and out at the other end as the washed product. In moving
across, the slate, pyrites, barytes, and all heavier particles find
their way through the bed to the bottom of the jig and flow out
through the slate valve in a constant stream. The washed coal is
taken to the boots ov o2 and the washed slate to the boot q, by
means of gutters. Perforated bucket* elevators nlt n2 moving
slowly to drain off the water, raise and dump the washed coal into
the conveyer p, which carries it to the storage tower. The slate
elevator r discharges into small cars, which the picking boys push
to the slate dump. The amount of water used in this plant is very
small, as the same water is used over and over. By allowing it to
flow through a settling tank u, tolerably clear water is not only
obtained, but all the sludge or finer particles of coal that are held
in suspension and would otherwise be lost are saved and elevated
to the washed-coal elevator n± by the perforated bucket elevator w.
The water from the settling tank flows back to the centrifugal
pump v, which again forces it to the jigs, etc."

The capacity of the washer is 500 tons per day of 10 hours,
though owing to the- limited output of the mines at present, it
has not been handling much over 300 tons.

The table of analyses, page 79, shows the efficiency of the
washer very plainly. The coke is hard and exceptionally low in ash.

To obtain the average for a day's run in this table, samples of
run-of-mine and of washed coal were taken every half hour:

17303— in

FIG. 25. PLAN OP COAL- WASH

PLANT AT COAHUILA, MEXICO

ferr

r.o3 no. xo

if TJ

•

17303— in

FIG. 25. ELEVATION OF COAL-W

S/cfe

\TG PLANT AT COAHUILA, MEXICO

TREATISE ON COKE

RESULTS OF WASHING AT BROOKWOOD, ALABAMA

Date

Average Per-
centage of Ash
in the Run-
of-Mine Coal

Average Per-
centage of Ash
in the
Washed Coal

Percentage
Reduction in
Ash

Average Per-
centage of Ash
in the Coke

December 21

15.32

8.15

46.9

10.10

December 23

14.10

7.50

46.9

9.50

December 31

15.07

6.50

56.8

1 anuary 5
anuary 6

20.83

17.18

8.10
7.60

61.3
55.5

10.50
10.50

anuary 7 . .

16.38

6.50

60.2

9.27

anuary 26
anuary 27
January 28

20.90
17.37
18.63

5.50
5.40
7.15

73.5
69.0
61.7

February 13
February 14
February 17

21.12

4.81

77.5

6.10

7.40
7.80

The run-of-mine that is washed is a mixture of the No. 4 and
No. 6 seams; that from No. 4 is finely interstratified with slate and
contains an abundance of sulphur. There is a lack in sulphur
determinations, but a casual examination of the washed slate and
of the washed coal shows that it is removed almost entirely. The
washer is the first of its kind in the United States, though not in
America, as there is a 300-ton plant in successful operation at
Ferrona, Pictou County, Nova Scotia; the New Glasgow Iron,
Coal, and Railway Company operate it in connection with their
blast furnace.

Mr. Stein writes that an addition will be made to the plant in
the shape of a large elevator with automatic dumper for feeding
coal from a storage bin; this will hold 250 tons of coal, and will
enable the company to operate the washer to its fullest capacity
during the day. Another perforated bucket elevator will also be
added for removing the dust from the settling tank.

The sulphur has been reduced to .52, .54, and .53 per cent,
from 1.65 per cent, of sulphur in the coal of one of the seams used
in making coke, and 1.15 per cent, of sulphur in the coal of the
other seam. This shows good work, with a very small loss of
fine coal.

COAL-WASHING PLANT FOR BITUMINOUS COALS AT
COAHUILA, MEXICO

I am indebted to Mr. Edgar G. Tuttle, E. M., for the following
account of the Coahuila plant, which was first published in the
School of Mines Quarterly, No. 4, Vol. XVII.

Fig. 25 (a) and (b) shows a coal-washing plant arranged for
treating about 300 tons a day of 10 hours; the design embodies
almost all of the requirements likely to be met with in coal washing.

80 TREATISE ON COKE

The extent of sizing by screens and the washing are designed to
treat a coal whose impurities separate with more difficulty than
in the case of impurities as heavy as iron pyrites or heavy slates.
For a simpler treatment, the plant can be considerably modified.
The relative positions of the machines may require to be differently
arranged under various circumstances connected with the location,
and depending on the respective distances and directions at which
the coal arrives at the plant and the point at which it is discharged.
The main features of the plant can, however, be carried out to
suit the above by making as many right breaks in the lines of
machinery as may be necessary to bring the plant in the desired
position and connect the points of receiving and delivery with its
entering and terminating points. If, then, the position of any
machine is such as not to permit of being driven by the main-line
shafting, right-angle gears can be introduced to transmit power
thereto.

In this plant, the screening is designed to be done wet; where
the screening is done dry, greater fall throughout the line is neces-
sary. Generally, where screening is done in the dry way, it is
accomplished in one large revolving screen or a drum screen consist-
ing of two or three concentric screens inside one another, each of a
different mesh of perforated metal or wire cloth. Sometimes a
shaking screen with several parallel screening surfaces, one above
the other and each of different mesh, is used to produce as many
sizes as desired. Where the screening is done dry, the jigs should
be located more directly below the screen, or that part of the screen
from which they receive the sized product.

The treatment' of the coal in this plant is as follows: The coal
received is that which usually passes through the screens in the
chute at the mine tipple. This may be what falls through flat-bar
screens spaced about 1^ inches apart, or through revolving or sha-
king screens of somewhat larger mesh. It is assumed that the coal
sent to the washer will not be much larger than 3 inches at its
greatest dimension, as all above this will be better hand-picked at
the tipple and is not readily handled in the size of elevator buckets
that are of sufficient capacity for the greater proportion of the
sizes requiring treatment. The coal less than 3 inches in size is
then either dumped into the pit a from the chute of the mine tipple,
if it is located near enough to the washer plant, or it is unloaded
into the pit from railroad cars. From here, the coal is lifted by
the elevator b to the shaking screen c, which has an upper sheet
steel screen with 1^-inch circular perforations and an under one of
j-inch perforations. The coal is here separated into the following
sizes and disposed of as indicated: All greater than 1£ inches
passes over the screen and is delivered on the picking belt d. Coal
passing through the 1^-inch screen and over the f-inch screen (size
} inch to 1^ inches) falls between the coarse rolls e, which reduce
the coal to inch or less.

TREATISE ON COKE 81

The coal passing through the f -inch perforations of the shaking
screen (size 0 inch to f inch) falls to the foot of the elevator /. This
coal, with that from the rolls reduced to f inch or less, is lifted by
the elevator / to the revolving screen g at the head of a line of three
screens, which are each 4 feet in diameter and about 11 feet long,
and of the same construction except that they are covered with
screens of different mesh. The screen g is divided into four sections
in the direction of its length and each section is the same width;
the first two are covered with sheet iron or steel with ^-inch circular
perforations and the last two with screens of f-inch perforations.

The coal passing through the |-inch screen openings (size 0 inch
to \ inch) falls to aprons below, which are on each side of the screen
and slope into an inclined gutter directly below the screen, which
leads this material (0 inch to \ inch) into the screen h, with the
water, which falls from a spray pipe over the length at the top of
the screen to wash out particles becoming wedged in the holes and
clear the coal from sticking to the sides of the screen. The water
is sprayed similarly on all the screens, and falling through into
the gutter, carries the coal passing through the perforations of one
screen into the next screen.

The coal passing through the J-inch perforations (size J inch to
J inch) is -spouted to the jigs i, j, k, and /, which are designed for
treating coarse sizes and are provided with crank-arm or slide-yoke
motion, so as to have a quick down stroke of the plunger and a
slow return movement, and speeded to make about 60 strokes a
minute of 3-inch to 4-inch throw, and if a middle product is to be
treated the screens are arranged for drawing this off for retreatment.

If there has been any of the }-inch to 1^-inch coal from the
shaking screen that has not been reduced to less than f inch by
the rolls, after this has been elevated and passed into the screen g,
it will go over it and out at the end, and will be again fed to the
rolls e for reduction, and will be then hoisted by the elevator /
with the coal from the shaking screen, as already described. If the
rolls e do not reduce this amount of coal sufficiently, it can be
passed to the rolls b' for smaller crushing and treatment with other
coal passing through these rolls.

If, however, the coal passing out of the screen g is not too large
for washing and the impurities are sufficiently unlocked without
further reduction, it may be cleaned completely by washing on
jigs treating coarse sizes, or it may be sufficiently cleaned to be
used for certain purposes that do not warrant its reduction to
smaller sizes for what further improvement may be thus made
possible. In this case the coal, as it passes out of the screen g, can
be spouted to one or two of the first jigs treating coarse sizes, using
for this purpose, say, jigs j and k (that is, for coal larger than
} inch), and jigs i and / for the sizes \ inch to J inch, or such pro-
portion of these or other jigs as may be necessary for the quantity
of these sizes produced.

82 TREATISE ON COKE

Although a preliminary examination and test of the coal will
determine the quantity of each size of the larger sizes of coal, and
the number of jigs required to treat it, it is advisable, in designing
the jigs and arranging them in the plant, to provide for possibilities
of treating larger sizes on some of the jigs intended to treat smaller
sizes, or the reverse. The points to be considered in this connec-
tion are: (1) Designing jigs so that the length of the stroke and
the number per minute can be readily increased or diminished to
suit the sizes treated. (2) Locating the jigs under the screens so
that the material likely to be received from one or more points of
the same can be readily spouted to the jigs with changes in sizes
to be treated thereon. (3) Arranging the jigs so that the washed
product and the refuse discharged therefrom can be readily deliv-
ered to the points desired, which may vary with the sizes produced
on account of possible difference in the quality of different sizes.
(4) In case a middle product results requiring treatment, the jigs
should be arranged and handily located so that these can be drawn
off and discharged to rolls for reduction, or else be handy to an
elevator to lift this product to rolls intended for this purpose or
for smaller crushing.

The 0-inch to ^-inch coal carried into screen h is separated into
sizes as follows : Size 0 inch to J inch is screened through the first
two sections with J-inch holes, and is caught by the aprons and
gutter below the screen and spouted into the screen m. The coal
passing over the first two sections of screen h will be J inch to ^ inch
in size. This passes into the last two sections of screen h with
f-inch perforations, which separate it into two sizes, as follows:
First, coal passing through the f-inch holes (J inch to f inch),
which is spouted to jigs n and o\ second, coal passing over and
out of the end of this screen (f inch to £ inch), which is spouted
to jigs, p, q, r, and s.

The coal spouted from the gutter under the screen h into screen
m (0 inch to i inch) is separated as follows: The coal passing
through the first two sections of this screen with -r6--inch holes
(size 0 inch to iV inch), falls into the gutter below it, and if suffi-
ciently pure, need not be treated, but can be spouted directly into
the sluice boxes carrying washed coal from the jigs. If, however,
it contains impurities and there is a considerable quantity of this
size, it will require treatment. Generally, it will suffice to spout
this coal into the jigs / and u arranged for treating this size and in
the jigging thereof most of the overflow will be pure coal with
possibly some light mud, which will subsequently pass off in the
water overflowing from the settling tank where the fine coal will
be treated for its deposition from suspension in the water from
the jigs. If, however, the impurities separate with difficulty, this
material 0 inch to Tg- inch will be carried along in the gutter under
the screen m to the hydraulic classifier v for treatment, as will
be described.

TREATISE ON COKE 83

The coal, -r6- inch to J inch, passing into the last two sections
of the screen m with J-inch holes, is separated as follows: That
passing through the screen sections (iV inch to J- inch) is spouted
to jigs w and x. The coal passing out of the end of this screen is
sized J inch to J inch, and is spouted to jigs y and z.

The coal is spouted from screens to the jigs through troughs
6 inches square or so inside, lined with No. 12 or 14 sheet iron.
Sometimes storage boxes are introduced below the screens to hold
the sized screenings, and from these it is spouted to the jigs. They
are, however, apt to clog up with wet screenings. A more satis-
factory means of insuring a steady supply to the jigs is to arrange
a regular feed to the elevator b, and to keep a sufficient supply of
raw coal always on hand in the pit a.

The jigs i, j, k, and / are of one compartment about 3 feet square,
and, as mentioned, are arranged to draw off a middle product, that
is, material on the jig bed from a horizon between the top layer
of washed coal and the bottom layers of slate. Impurities in the
form of small particles closely adhering to the coal are most apt to
occur among the larger sizes of coal; or, if consisting of particles
of coal of an inferior quality, or of bony coal, intermediate in specific
gravity between the lighter coal at the top of the bed and the slate
or impurities on the bottom of the jig bed, they will occur in a
layer midway between the two, whence they may be drawn off in
jigs arranged for the purpose. The remaining jigs are of two com-
partments, each compartment being 24 inches by 32 inches. These
jigs are speeded at 100 to 180 revolutions, or double strokes, per
minute, and with throws of 2£ inches for the larger sizes to J inch
for the smallest sizes. If the impurities are with difficulty sepa-
rated from the coal in the smaller sizes, it may be necessary to
have three compartments instead of two in the jigs w, t, u, and x,
so that the material will travel over a greater length of jig bed in
being treated, thus allowing more time to effect the separation.

The coal after being washed passes out of the jigs at the over-
flow into the trough a, and is carried by the water from the jigs
to the drainage screen cr , which is preferably covered with sheet
copper of gV- inch perforations, where the water is removed and all
coal larger than -2-5- inch passes over the screen and out at the end
to the elevator d', whence it is raised high enough for discharging
either into bins or else to a point for loading.

Jigs may be used from which the water does not flow, and
from which the coal is removed by elevators with perforated
buckets, or if the coal overflows with water from the jigs, the
water may be drained therefrom by passing over screens forming
the overflow chute. In this case, there must be sufficient fall to
cause flow if the coal is to be chuted dry from the jigs to the eleva-
tor d', or the jigs may have less inclination or be located on the
same level, provided that conveyers are introduced to convey all
the coal from the jigs to the foot of the elevator d' .
4

84 TREATISE ON COKE

Where coal is to be stored in bins of considerable extent a cori-
veyer e' , into which the coal from the elevator is delivered, is
arranged at the top of the bins. The conveyer travels the length
of the bins near their center lines, and is so designed that by means
of openings in the bottom of the conveyer box, that can be opened
or closed as desired, the discharge of the coal into the bin from any
point thereof is effected, permitting of an even distribution of
coal in the bin. The buckets of the elevator d' are perforated so
as to drain as much of the water from the coal as possible. The
water and coal less than -£$ inch in size, passing through the drain-
age screen cf , fall upon an apron and into the gutter, from which
they flow by the trough /' to the settling tank gr . The trough ef
leads to one side of the settling tank, and, by means of small adjust-
able openings along the side of this trough, the discharge of the
water with the fine particles of coal into the settling tank can be
regulated so as to be evenly distributed, which is important to
secure effective settling. The water and fine coal are discharged
into the settling tank on one side of a partition h' that extends
the length of the tank with its bottom 3 or 4 inches below the
surface of the water; this causes the water flowing into the tank
to move first in a downward current, and then across the tank, as
an even, slowly moving body of water, toward the discharge side.
Surface currents are thus prevented, which would otherwise occur
and carry the material over the surfaces and out at the discharge
without settling.

The settling tank is 12 feet wide, 32 feet long, and 4 or 5 feet
deep at center, with sides sufficiently inclined that particles will
not settle thereon.

The suspended coal of sand and slime sizes is thus settled, and,
by means of a slowly moving drag i' with pedals or scrapers 4 feet
apart, the settlings are moved gently along and finally scraped
up an incline and out of the tank and dropped off at the end of the
drag, which delivers the settlings at a point where they will fall and
mix with the coal from the discharge end of the drainage screen c'
and both be taken up by the elevator d' .

The water overflowing from the settling tank with what sus-
pended matter it may still contain, which will be very small, over-
flows into the trough /'. It is important that this overflow be
truly level so that the water from the settling tank will overflow
in an even sheet, thus insuring a slowly moving current through
the settling tank. From the overflow trough /' the water flows
into the trough k' to the sump /', from which it is lifted by the
centrifugal pump mf and delivered through pipes or launder boxes
to screens and jigs treating the smaller sizes. Any overflow water
from this sump passes to the sump ri .

The refuse, impurities, slate, etc. drawn off from the jigs, as
well as the material settling through the sieves of the jig bed and
released at the bottom or mud-discharge, are conveyed with the

TREATISE ON COKE 85

water escaping therefrom by the slate troughs to the pit tf . These
troughs are. more highly inclined for the large-sized slates to facili-
tate their movement to the pit </. The slate troughs are best
located on the floor near the base of the jigs or else below the floor
line, with the flooring from all the jigs sloping thereto so as to
drain off all water escaping or leaking from jigs, pipes, troughs, etc.,
and keep the floors clean. The slate troughs are usually made
4 inches to 6 inches square, lined with No. 12 or 14 sheet iron,
curved at the bottom. The amount of water escaping with the
refuse is comparatively small in comparsion to that flowing with
the washed coal from the jigs. The pit or need, therefore, not be
very large. The one here shown is 8 feet square at top, with sides
sloping about 50 degrees, and 3 to 3^ feet deep.

The refuse is removed from the pit o' by the elevator pf with
perforated buckets to drain off the water taken up by them with
the material. The refuse is discharged at the elevator head into the
storage bin q' for removal by railroad or dump cars or otherwise.

If the location of the plant is on an elevation where there is
considerable low land that can be filled, the refuse, escaping with
water from the jigs treating the smaller sizes, can be carried in
troughs with a grade of 4- or 1 foot fall per 100 feet to such points
where the refuse can be disposed of to make fills. If there is
sufficient fall, the refuse from the jigs treating coarser material can
be likewise disposed of in troughs of steeper grade, viz., 2 per cent,
to 4 per cent. fall. If there is only sufficient fall for disposing of
the smaller-sized refuse as above, the heavier or larger-sized refuse
may have to be removed by the elevator p' and disposed of as
indicated.

The water, after the refuse has been settled therefrom into the
pit or , overflows into the trough r' and flows to the sump n', from
which it is lifted by the centrifugal pump s' and is delivered
through pipes or water troughs to the jigs treating the coarse
sizes and the rolls.

The middle product drawn off of jigs i, /, k, and / is spouted to
the roll bf and reduced from J inch or f inch to about f inch
downwards, depending on how small it is found necessary to reduce
the middle product to unlock the impurities. This material is
then lifted by the elevator f high enough to be discharged into the
revolving screen h and there treated with the sizes of coal dis-
charged into this screen from the screen g ; this is the case if the
middle product has been reduced to sizes small enough to be sized
in the screen h. If it is not necessary to reduce all the middle
products to sizes smaller than those treated in screen g, it is lifted
by the elevator f only high enough to be discharged into the ele-
vator /, and from there it is handled the same as the other coal
lifted by this elevator.

The coal that passes over the l^-inch perforations of the shaking
screen c, which will be from 1 J inches to 3 inches or so in size, is

86 TREATISE ON COKE

delivered on to the traveling picking band or belt d, where it is
hand-picked by as many men or boys located along both sides of
the belt as may be required to thoroughly clean the coal as it is
conveyed toward the storage bin u' , where it is dumped for loading
on railroad cars. This belt is 3 or 4 feet wide and about 40 feet
long, and has a slow travel of about 30 feet a minute. It is com-
posed of sections of wood or iron 3 inches to 6 inches wide by
3 feet or 4 feet long, whose ends are fastened to sprocket, or link,
chains. The sections of wood or iron are either beveled, jointed,
grooved, or hinged, so as to lay close to each other and form a
flexible band readily curving around the sprocket wheels of the
driving gear. If these sections are of iron they generally lap
each other where their sides come in contact and form a sort of
hinge joint.

If the coal treated on the picking band is of large sizes requiring
sledging and slabbing, so that it is broken up in cleaning and con-
siderable small coal results, the sections or slats of the picking
band are sometimes slightly separated from each other so as to
act somewhat like a screen and allow the small coal produced to
fall through and thus separate it from the large lumps in loading.
The impurities picked from the coal traveling on the band, which
may contain more or less coal, are dropped into chutes leading to
the pit v' or else are thrown into this pit, and from there are lifted
by the elevator «/ back to the washer building and high enough to
be discharged on the rolls e for reduction and delivery to the ele-
vator / for the usual treatment in the plant.

If there is much refuse picked from the lump coal at the mine
tipple and it has considerable good coal adhering to it, it can be
broken by sledging, or a special crusher may be erected for redu-
cing it, after which it is discharged into the pit v' and lifted by its
elevator for treatment in the plant with other coal from the pit.
If this waste removed at the mine tipple is not too large and the
tipple is near the washer plant, it may be chuted directly to the
rolls e. If the tipple is located at some distance and this refuse is
to be treated, it will be necessary to take it there by railroad cars,
dump cars, or a conveyer, if the distance is not too great. If the
amount of coal requiring hand picking is large, it may be necessary
to introduce two picking belts. This is generally preferable to
increasing the length of the belt with increased quantity to be
treated. The maximum length for a picking belt should be 30
to 50 feet.

If the impurities in the sizes f inch to 1| inches, separated on
the shaking screen, do not adhere to the coal and are readily hand-
picked, they need not be reduced in the rolls, as mentioned, but
can be discharged into a second picking belt that may be intro-
duced for treating these sizes as explained for the 1^-inch to 3-inch
sizes. They may be delivered into bins, if they are to be loaded
for shipment, or the picking belt on which they are treated may

TREATISE ON COKE 87

have such a direction of travel as to finally discharge them at the
foot of elevator df for removal with the other coal hoisted by this
elevator. Or, if the impurities are in considerable quantity in
the f-inch to IJ-inch sizes, they may be removed by washing, if
they do not adhere to the coal, so as to require crushing to liberate
them. This size may then be dropped from the shaking screen
with the 0-inch to f-inch size and hoisted with it by the elevator /
to the screen g without first passing through the rolls e. In this
case, this sized coal will, as previously explained, pass over the
screen g and out at the end, sized } inch to 1^ inches, and fall into
the two jigs j and k, or others that may be required for treating it.

The hydraulic classifier v consists of a box of two or more
compartments, 2 feet or more in width, and of such length
as is determined by the number of classes of sizes it is intended
to produce. The sides are sloping to insure proper discharge of
the materials settled therein from the bottom, which is fitted some-
times with piping, as will be described. A partition extending
2 inches or 4 inches into the water of the classifier extends across
its width so as tb deflect the inflow of water and direct its current
downwards, thus preventing surface currents.

The treatment of 0-inch to -iV-inch size flowing from the gutter
under screen m to the classifier is as follows: With the diminution
of the velocity of the current of water flowing from the narrow
channel of the gutter into the wider channel of the classifier, there
will be deposited in the first compartment %' of the apparatus,
such smaller sizes of the heavy impurities and such larger sizes of
the lighter coal as are equally settling. Likewise in the second
compartment y, there will be a settling of relatively smaller sizes.
It will depend considerably on the nature of the impurities and
coal in these smaller sizes as to what the treatment will be.

The ideal method of treating material classified as above is to
submit it to treatment with water on machines of the type of the
inclined table, or shaking or bumping tables, where the larger,
specifically lighter particles of coal will be moved farther down the
plane by the water than the smaller, specifically heavier particles
of slate or impurities. In coal washing, however, the cost of this
treatment is too great and the small-sized material is usually in
too small a quantity and of insufficient value to warrant the
expense of the treatment, or the coal may be sufficiently rich not to
require treatment.

The trough washer is a machine nearest approaching the types
above mentioned that it is advisable to incur the expense of,
although the treatment of the coal therein is not perfect. This is
used for sizes up to 1£ inches or so in rough washing, but is better
adapted for the smaller sands and slime sizes or the products of
the hydraulic classifier in question.

The trough washer consists of a trough inclined 1 foot in 12,
from 40 to 60 feet long and 1 or 2 feet wide at bottom ; sides sloping

88 TREATISE ON COKE

from 50° to 60°. In this, a scraper chain works, with a scraper
4 inches to 6 inches deep and 6 feet apart, closely fitting the bottom
of the trough and moving slowly up the incline. The fine coal is
fed into the trough midway between the two ends and 60 to 150
gallons of water a minute are fed into the trough at the upper end.
The action of the water is to wash the coal down the trough and
over the tops of the scrapers, while the heavier impurities settle to
the bottom and are moved up the trough by the scrapers and
discharged over the top. The coal discharged at the lower end of
the trough with the water is drained over a screen and the water
thus separated and reused, but preferably it can be discharged
into the settling tank /' and there removed by the drag where
this fine coal can be handled and used better when mixed with
coarser coal.

Generally, however, a separation of the impurities from the
classified products of the two compartments of the hydraulic classi-
fier that will be sufficiently satisfactory where the quantities are
small can be effected by allowing the settlings from the compart-
ment yf to pass out of the spigot zf to the jig x, and those from y
flowing from the spigot a" to pass to the jig u, where, in rapid jig-
ging, somewhat of a separation is effected if the strokes of the jig
last only during the period of accelerated velocity of fall of the
particles. In this case, the larger lighter-weight particles of coal
require a longer time before arriving at their maximum velocity
of uniform motion than the smaller heavier particles of impurities.
With strokes of the jig applied to last for -§- or iV second or so,
particles of coal and slate that are equally settling in the classifier
may be separated to some extent on the jigs, the coal being main-
tained at the top of the bed and the slate settling to the bottom
as usual.

If there is only a slight difference between the specific gravity
of the coal and slate, it may be advisable to make the smallest size
treated on the jigs from the screens -2-B- inch or gV inch ; in this case,
the TV-inch screen should be replaced by a gV-inch or -3-2-inch copper
screen of perforated metal or wire cloth. In this case, the largest
size treated by the classifier will be -^V inch or -£$ inch. The use
of small screens should be avoided, however, if possible, as their
life is short and the value of the material rarely warrants the
expense. . .'•'

The classifier is arranged so that the discharge can be made
continuous from the bottom by the spigots sf and a" for drawing off
the particles and what water escapes therewith. The velocity of
the water traveling across the classifier from the receiving to the
discharge end can be reduced according to the amount of water
fed into the classifier and the amount drawn off at the bottom flow.

If it is found necessary to prevent a settling of too small sizes
in the first or second compartment of the classifier and at the same
time effect somewhat of a separation, an inflow of clear water can

TREATISE ON COKE 89

be arranged, which is admitted by the pipes at the bottom and
regulated by the valves b" and c" . This inflow is through pipes of
larger area than the outflow through the spigots zr and a" , and the
velocity of the inflow is not so great but that it will allow the
particles of the sizes desired to settle down through its current and
escape by the spigots z' and a" '. This ascending current may have
to be varied from -nj inch to 3 inches a second, so that an inlet
pipe of 1^ inches, 2 inches, or 3 inches may be necessary; the larger
the better to provide for increasing or decreasing the sizes of the
classified product desired.

A separation of the limits of sizes desired can be thus effected
by maintaining just sufficient upward current so that the smaller
sizes will not be permitted to settle, but the larger ones will l?e
allowed to fall through the current and be discharged by the spigots
z' and a" , which can be plugged with reducers to J inch or J inch,
as may be required to regulate the outflow, which will depend on
the rapidity with which the larger sizes accumulate. By testing
the products under various flows of inlet and discharge currents,
it will be determined what conditions can be produced and accord-
ing to which the product can be best treated.

It may occur that the discharges from zf and a", under an
upward current, are entirely impurities and the overflow at d" is
entirely pure coal, in which case the coal can be run directly in with
other washed coal to the settling tank. If this should contain much
mud or .small thin disks or plates of impurities, it may be possible
to have these pass off as suspended matter in the overflow from
the settling tank. If, however, the tendency of this form of impuri-
ties is to settle in the settling tank, they may be separated in the
classifier by regulating the flow of water so that they will be carried
out over the overflow thereof.

If the light-weight impurities can be thus disposed of, and if it
is possible to regulate the lower inflow so as to have the heavier
impurities only discharged from the spigots z' and a", the coal may
be separated therefrom and maintained in the classifier midway
between the bottom discharges and the overflow.

In this case, there should be two sets of hydraulic classifiers, so
that the current of water from the gutter under the last screen can
be turned to a second classifier when the first has become filled.
The first can then be cleaned by allowing the impurities to discharge
at the spigots until the coal begins to flow. Then the washed coal
can be spouted to the washed-coal trough or to the settling tank.
When the classifier is emptied, it will be ready for use when the
second classifier has become filled.

If the impurities are all light weight, they may be separated
from the coal by adjusting the amount of the bottom discharge,
or, if necessary, of the inlet current to such a point that the coal
will be discharged from the bottom, while the impurities pass to
the overflow d" .

TREATISE ON COKE

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TREATISE ON COKE 91

In all these adjustments to regulate the amount of water
admitted to the classifier, or to form an upward current, or of the
amount allowed to discharge, the resulting current in compartment
y should be somewhat diminished from what it is in compart-
ment #', in order to allow a settling of the particles in compart-
ment y, which are smaller than those settling in compartment x' '.
If the particles treated are very small and very light weight, it is
advisable to make the compartment y wider than compartment x?
to insure a diminution of the velocity of current necessary.

WATER REQUIRED IN PLANT

Clear Water CUBIC FEET CUBIC FEET

4 Revolving screens 1 cubic foot a minute = 4.0

2 Rolls 1 cubic foot a minute = 2.0

4 Jigs (sand and slime sizes) . 4 cubic feet a minute = 16.0
Classifier. . 2 cubic feet a minute = 2.0

Total raised 45 feet = 180 gallons = 24.0 24.0

Reused Water CUBIC FEET

igs, i to ^ sizes 4 cubic feet a minute = 8.0

igs. | to § sizes 5 cubic feet a minute =10.0

igs, | to J sizes 5 cubic feet a minute = 20.0

igs. $ to :

sizes . . 6 cubic feet a minute = 24 . 0

Total raised 24 feet = 465 gallons = 62 . 0 62 . 0

Total fresh and muddy water = 645 gal. = 86.0

HORSEPOWER REQUIRED

For Jigs

NUMBER SIZE HORSEPOWER TOTAL HORSE-

OF JIGS TREATED PER JIG HORSEPOWER POWER

2 0 toT\ 1 2.0

2 TV to i 1 2.0

2.5
2.5
5.0
6.0

Total.. ..20.0 20.0

1 Shaking screen 2.5

1 Coarse rolls 8.0

1 Fine rolls. . ; 3.0

1 Picking belt 2.0

2 Revolving screens, 4 feet diameter, 1 1 feet long 2.5 5.0

2 Revolving screens, 4 feet diameter, 11 feet long 1.5 3.0

1 Drag for settling tank 1.5

1 Centrifugal pump, 180 gallons, 45 feet, 3-inch suction, 2-inch

discharge 4.5

1 Centrifugal pump, 645 gallons, 24 feet, 5-inch suction, 4-inch

discharge 7.5

1 Conveyer 2.0

1 Elevator, 400 tons, 10 hours, 42-foot* lift 2.5

92 TREATISE ON COKE

1 Elevator, 300 tons, 10 hours, 40-foot lift 2.0

1 Elevator, 300 tons. 10 hours, 60-foot lift 2.4

1 Small elevator, 60 tons, 10 hours. 36-foot lift (middle product) 1.0

1 Small elevator, 60 tons, 10 hours, 26-foot lift (refuse) 1.0

1 Small elevator, 60 tons, 10 hours, 30-foot lift (pickings) 1.0

Total horsepower *. 68 . 9

Add 15 per cent, for friction 10.0

Total 78.9

About an 85-horsepower engine and a 100-horsepower boiler
will therefore be required.

Crushing Rolls. — The coarse rolls are 18 inches wide and 19^
inches in diameter and corrugated horizontally. They make 30
revolutions per minute, or have a tangential speed of about 155 feet,
and break about 30 tons to ^-inch size or 70 tons to 1-inch size
in 10 hours. If a greater amount of the larger size is to be reduced
than above, either larger rolls or two of the above size are neces-
sary. If the coal sticks to the rolls, as it will if clayey slate is
present, it is preferable to use tooth rolls; or these should be used
if the coal is very friable and apt to become reduced to too small
sizes. Toothed rolls have a somewhat higher speed at the per-
iphery, generally about 400 to 800 feet a minute. One of the rolls
of a pair is in a movable box connected with rods to steel or rubber
springs, so as to allow the rolls to yield in case of hard pieces of
iron, etc. getting between the rolls that would otherwise break
them. A spray of water is fed into the top of the rolls to keep
them clear of adhering particles. Steel brushes are also arranged
back of the rolls to scrape against them and remove particles
becoming wedged between the corrugations or teeth.

The fine crushing rolls need be only about 14 inches in diameter
and 12 inches wide, but it is preferable to have them as large as the
coarse rolls, in the event of it being desired to change the grading
of the crushing throughout the plant.

Revolving Sizing Screens. — These are 4 feet in diameter and
about 11 feet long. The surface of the screen is divided into four
sections by five spiders, keyed or setscrewed to a 2yf-inch shaft.
Each section is covered with perforated sheet metal, requiring four
sheets 32 inches by 39 inches to cover each section.

The screens have a slope of 8 inches to 12 inches in their entire
length; the shaft being laid inclined. The sections of sheet metal
may be either riveted or fastened by bands to the spiders, the
latter method being preferable for despatch in case of repairs.

Conical screens may be used, in which case the shaft is laid
level, the slope of the sides being sufficient to assist the passing
of the material through it. The shape of the screen sections in
this case may give more trouble in case of repairs than with cylin-
drical screens. The speed of screens is about 22 revolutions per
minute, or the peripheral speed will be about 270 feet a minute.

TREATISE ON COKE 93

The screens are sprinkled by a spray of water from a IJ-inch
pipe located above the screens and having J-inch holes every inch
or so on the under side of the pipe.

CAPACITY OF REVOLVING SCREENS

SIZE OF NUMBER OF SQUARE

SCREEN FEET OF SCREENING

PERFORATION SURFACE REQUIRED

INCHES PER TON IN 10 HOURS

U to 2 <.'• .32

1 to H 43

f to 1 72

| to f 3.70

*to | 5.40

0 to J 18.00

The above capacity is variable, depending on the amount of
other sizes mixed with the sizes to be screened. Shaking or flat
screens have greater capacity than revolving screens and are
preferable where they are not to be erected too high on the struc-
ture, where they cause jarring to the building.

Elevators. — Large elevators are best arranged when buckets
are mounted on double chain formed of 12-inch or 15-inch links
connected with rods into which the links on either side of the
elevator buckets are bolted. The buckets are bolted to two straps
hinged from one rod to the other. The elevator frame is con-
structed of wood with guides on either side, which may be covered
with strap iron on which the elevator rods slide in the upward
movement of the elevator, or the guides may have angle-iron
sliding pieces, in which case the links slide therein and are guided
by them. The sides of elevator buckets should be of No. 14 Otis
steel and the front of No. 12 steel, with ribs at the top, front, and
sides. Their shape should be somewhat rounded at the bottom to
prevent material becoming wedged therein, but not too rounded,
or where they discharge at the elevator head, the material may fall
on the back of the bucket below it and inside of the elevator frame.

The elevators should be as far from the vertical as possible for
the most perfect discharge at the elevator head, otherwise it may
be necessary to introduce special devices for perfecting the dis-
charge. The usual travel for an elevator is about 100 to 150 feet
a minute, although where they are vertical or nearly so a speed of
200 or 225 feet a minute may be necessary to insure proper dis-
charge. The slower the speed, the less the wear is on the elevator.

Small elevators may be mounted on small sprocket-chain, or
link, belting with small cast- or malleable-iron buckets ; their speed
may be 150 to 200 feet a minute or less. The chains supporting
the elevators may be operated by sprocket wheels or hexagonal
or octagonal drums driven by a pulley with gearing. Either the
upper or lower set of sprocket wheels or drums should be in an

94 TREATISE ON COKE

adjustable boxing, which will permit of moving the bearing of
the sprockets by screws so as to tighten up the elevator chain as
it becomes worn.

Jigs are preferably built of wood as they require less expensive
foundations, and although requiring more frequent repairs than
iron jigs they are moderate in first cost, and wearing parts in iron
jigs being more expensively replaced than in wooden jigs, the cost
of repairs in the end is not much greater in wooden than in iron
jigs. Jigs treating large sizes have one compartment about 3 feet
square and the stroke is given by a crank-arm movement making
sixty 3-inch or 4-inch strokes per minute. The depth of the jig
frame should be about 10 inches, at least, below the overflow. The
jig frame may consist of an iron-bar grating or of copper cloth or
perforated metal of about 8 mesh. The discharge for the lower
product should be as automatic as possible and should preferably
extend across the width of the bed. The coarse jigs should be
arranged for treating the middle product, and the discharge should
also be constructed as above.

Fine jigs should have two compartments; it is rare that three
are necessary. Each compartment is about 24 inches wide and
32 inches long. These are provided with double adjustable eccen-
trics so that the length of the 'stroke can be varied as desired.
The plungers make 100 to 180 strokes per minute of 2^-inch to
£-inch throw each. The depth of the jig frame at the final over-
flow should be about 7 inches below it.

It is also desirable that the discharge for the lower product or
slate should be automatic and arranged across the width of the
jig beds, especially for the larger sizes, although the refuse in this
size material can be readily withdrawn by a small slate box 3 inches
or 4 inches square, located at either side of the jig, and the slate
tapped at about 2 inches above the level of the jig frame. The
jig frame is of wood, built of J" X 2|" slats with about 2J-inch
square openings. The width and length of the frame are about
^ inch less each way than the space they occupy in the jig.

Side-plunger jigs are preferable to facilitate repairs, although
there is more lost motion in these than in jigs with under pistons
or jigs in which the jigging is done on a movable bed. To facili-
tate determinations of speeding jigs it is preferable to have the
plungers and the jig beds of the same area. The bottoms of the
jigs should all be steeply sloping to one or more mud-discharges,
and the slope sufficiently steep and the mud-valve regularly opened
to prevent material clogging up the jig bottoms.

The jigs treating material from f inch downwards have some-
times a bed of feldspar through which the jigging is done. The
feldspar is of such size that the particles of coal and impurities
will not fall through its interstices. The mesh of the jig sieve need
then only be large enough to support the feldspar.

TREATISE ON COKE

An average estimate of the capacity of jigs is 1 ton for each
inch in width per 10 hours. This is independent of the length of
the jig. A safe, low estimate to provide against irregularities in
the supply of coal is as follows:

CAPACITY OF JIGS

Sizes Treated
by Jigs

Capacity in 10 Hours
Per Inch in Width

Width of
Jig

Capacity in 10
Hours

Inch

Tons

Inches

Tons

0 to A-

.30

ft.tof

.41

itol

.60

i to f

.84

f to £

1.00

Itol

. 83 to 1 . 20

30 to 43

SPEED AND STROKE OF JIGS FOR DIFFERENT SIZES

Size of Coal
Inches

Revolutions
of Jig
per Minute

Length of
Stroke
Inches

Mesh of Wire
Cloth of
Jig Sieve
Inches

Pulley
on Jig
Inches

Driving Pulley
on Main Shaft
Inches

2 to 3

50 to 60

H to 2

50 to 60

4 to 5

1 to H

60 to 90

3 to 4

Ito I

1 toll

100

2 to 3

6X6

16 to 18

m.1

110

8X8

Ito f

120

10 X 10

Ito f

130

10 X 10

ft to I

140

f to 1

16 X 16

•h to -A-

150

f tof

20 X 20

0 to ^o-

180

30 X 30

Picking Bands or Belts. — These are generally 4 feet wide and
travel at a speed of 30 to 60 feet a minute. For sizes from 1J inches
up, and in quantities of 30 tons per hour, belts should be 15 feet long
plus 10 feet more in length for each 3 per cent, of material picked out.

For sizes from } inch to li inches, the belt should travel at
the rate of 30 feet a minute; and for every 20 tons an hour, 15 feet
length of belt is required for each 1^ per cent, of material picked out.

If these sizes contain more than 4 or 6 per cent, of impurities,
it is generally preferable to treat them by washing.

Drainage Screen. — This is covered with No. 10 sheet metal,
preferably copper, to avoid rapid wear, which will occur with thin
sheet iron or steel if water is acid. This screen is geared the same
as the other revolving screens.

Settling-Tank Dr&g. — This is arranged with wooden pedals
about 2 inches thick, 4 inches to 6 inches deep and 2 or 3 feet

96 TREATISE ON COKE

long, attached to lugs on 6:inch links every 4 feet, and geared, as
shown, to move slowly in the bottom of the tank and not rile up
the settlings too much. The bottom and sides of these pedals have
pieces of rubber or leather fastened to them, so as to keep closely
in contact with the bottom of the tank along its bottom and when
mounting the incline.

Shafting. — The main shafting is 2yi inches in diameter driven
at 125 revolutions per minute. It is desirable, if possible, to avoid
any shafting at right angles to the main lines of shafting that will
require transmission of power by bevel gears, although this cannot
always be avoided.

Engine. — About an 85-horsepower engine will be required for
the size of plant shown, to have a safe allowance of power. This
should be mounted with a 10-inch shaft and a 16" X 52" driving
pulley. The engine should be located as near the machinery as
possible and thus reduce strain on the shafting.

Boilers. — About a 100-horsepower boiler, or two boilers of
50 horsepower each, should be provided for furnishing the power
required, with a safe reserve of power. The boiler should be
located handy to a point where the coal is dumped for receiving
its supply. This may be near either where the raw coal or the
washed coal can be had.

Location of Plant.— The arrangement of the plant can be carried
out if the location is on level ground or on a hillside. Unless the
material arrives at the plant from a higher elevation there is no
preference in one location over the other. A hillside location per-
mits of attaining the proper grades for lines of screens, jigs, and
other machinery nearer the natural ground. It may not be neces-
sary to support as much of the machinery in the building as on
a level location, nor require as many elevators, but the building
will be longer, and the increased number of floors requiring more
labor for proper attention to machinery does not make a hillside
location more preferable, whether its first cost is more or less,
than a level location. It is important that the floor of the build-
ing and bottom of the pits be located above the general level of
the ground so that they can be readily drained when desired.

Construction of Building.- — Generally a frame building on stone
foundations will answer all purposes, especially if there is no
danger in case of fire or if the screening is done wet, and heavy
machinery is not supported high in the building. In case of fire,
or if the expense is warranted, an iron-frame building covered with
corrugated iron is. preferable. If there is much heavy machinery
supported in the structure, the walls up to that height should be
of stone or brick and the balance of wood or iron. It is essential
that the location of the machinery and especially the jigs be such
that the building can be constructed to allow light to fall on them.
For this purpose the jigs and such machinery should be located
near the outer walls of the building, which will have windows in

TREATISE ON COKE 97

the sides, or if the jigs are located inside, no machinery should be
above them that will prevent the access of light thereto from
windows in the roof.

COST OF PLANT

Excavation, 500 cubic yards at 20 cents $ 100

Foundations, stonework, building 150 cubic yards at

$1.50 225

Stonework of washer machinery and pits, 70 cubic

yards at $2.00 140

Boiler and engine foundation and walls 500

Washer building, lumber, 80,000 feet B. M. at

$10.00 800

Other finishing lumber, doors, and windows 300

Carpenter work 1,200

Iron work 300

Coal-washing machinery 10,000

Erecting (machinist labor) 1,200

Freight, teaming 800

Total $15,565

The cost of the plant will vary considerably according to loca-
tion and distance from source of supplies. The above will be the
cost where material, machinery, and labor can be conveniently
obtained. Present cost of this plant in the United States would
range from $25,000 to $30,000.

COST OF WASHING PER TON, ON BASIS OF DAILY OUTPUT

OF 300 TONS COSTPER

Labor washing TON

1 foreman at $3 . 00 $3 . 00

3 jigmen at $1.50 4.50

2 feeders at $1 . 00 2 . 00

1 oiler at $0.75 .75

1 engineer and fireman at $2 . 00 2 . 00

$12.25-^300 =.040
Slate picking

6 slate pickers at $1 . 00 $ 6 . 00-f- 300 = . 020

Fuel, water, daily 4. 00 -r- 300 = .013

Oil, supplies, etc . . . . . 2. 00-=- 300 =.006

Maintenance and repairs, etc. to jigs, jig sieves,

screens 1,200.00 yearly = .010

Emergencies, renewals, and repairs to other

machinery 900 . 00 yearly = . 015

Total cost of washing per ton . = . 104

Improvement of Coal Effected by Washing. — The extent to
which coal can be improved by washing will depend on the nature
of the coal, the shape of its particles, the relative specific gravity of
the coal and its impurities, and whether there are also present
impurities of intermediate specific gravity, as bony and slaty coal.
In treating a Southwestern coal of the Laramie group of the

TREATISE ON COKE

Upper Cretaceous formation in a plant similar to the above, the
results obtained were as follows:

The plant referred to contains some important additions for
handling of the large coal, intermediate products and treatment
and settling of the fines, as well as other improvements. The
treatment in sizing and washing, however, is similar. Some of
the very purest coal, which was in small quantity and friable,
analyzed as shown in No. 1, its ash representing combined or fixed
ash which could not be removed by any process.

No. 2 represents an analysis of selected lumps with no visible
impurities adhering to them.

ANALYSES OF COAL

No. 1
Per Cent.

No. 2
Per Cent.

Moisture

.39

Volatile combustible matter

20.35

19.75

Fixed carbon

79.30

64.36

Ash

8.35

14.65

Sulphur

.85

The analysis of ash is as follows:
PER CENT.

Silica 7.30 Lime

Iron.. 1.01

PER CENT.

Alumina. ... . . 5. 10

The specific gravity of the lightest-weight coal was 1.39; of
bony and slaty coal 1.5 to 1.9; of slate and other impurities 1.8
to 2.3. There were also associated thin flakes of spar, lime, and
slates. The material used for washing was screenings passing
through a 1^-inch bar screen, whose analysis, as well as that of
the resulting products, is shown below, when the washer was not
overcrowded.

ANALYSES OF COAL, WASHED COAL, COKE, AND REFUSE

Moisture
Per Cent.

Volatile

Combusti-
ble Matter
Per Cent.

Fixed
Carbon
Per Cent.

Ash
Per Cent.

Sulphur
Per Cent.

Phos-
phorus
Per Cent.

Raw screenings
Washed coal

1.40

.79

19.79
19.10

60.25

69.35

17.33
10.24

.85

.52

Coke

.43

1.39

83.47

14.24

.82

.019

Refuse from waste box

2.22

15.76

30.96

50.12

.93

The ash in the screenings was reduced in washing from 17.33 per
cent, to 10.24 per cent. The inherent ash in the purest coal being

TREATISE ON COKE

8.35 percent, and somewhat higher in the average coal; the wash-
ing, therefore, reduced the ash to within 1.89 per cent, or less of
the combined ash.

The yield of washed coal from raw coal was 85 per cent., or
15 per cent, of the material was removed as impurities from the
raw coal, which con-
sisted of slate and
some of the poorer
quality of coal, as
bony and slaty coal.
The washed coal
was used for coke.
The yield of coke
from washed coal
was 70 per cent., or
the yield of coke
from raw coal was
59i per cent., and
contained 14.24 per
cent, of ash with
close washing. In
other words, 4^ gross
tons of raw coal,
when washed,
yielded 3.82 tons of
coal, which was
charged in a beehive
coke oven 6^ feet
high and 12 feet
in diameter, and
burned 48 hours,
yielding 2.67 tons
of coke.

Prior to Washing, pIG. 26. ROBINSON WASHER

the raw screening

yielded 66 to 70 per cent, of coke, much being lost as coke ashes

and containing 20 to 22 per cent, of ash.

ROBINSON COAL- WASHER PLANT

The Robinson coal-washing machine, Fig. 26, consists of a
wrought -iron receptacle, the shape of an inverted cone a, surrounded
by a jacket at the bottom, communication being made by a number
of perforations by which water at considerable pressure is admitted
into the cone. A vertical shaft having keyed on it four revolv-
ing arms, or agitators, b occupies the higher parts and sides of the
cone ; this part of the machine is kept in motion by a small engine
of, say, 10 inches diameter, cylinder fixed at c. The water supply d

100

TREATISE ON COKE

from the cistern e to the cone through the water chamber is regu-
lated by a valve. A supply of coal is admitted from the small-
coal apparatus down the slide, or spout, / into the open top of the
cone filled with water, the revolving or stirring motion being kept
up by the agitators, and the upward flow of water being con-
tinuous ; the result is that the stone and rubbish from the coal
fall into a chamber. At this point, two slides connected to neces-
sary levers are inserted, the bottom one being closed and the top
one opened during the operation of washing. To discharge the
rubbish, it is only necessary to shut the top slide and open the
bottom and the rubbish falls into a truck below. The clean coal
at the top passes down a sieve into a hopper g and thence into
another truck below^ beside the rubbish track, at will. Immediately
below the sieve ^jiijhi n i1 is fixed a collecting tank into which the
water is drajJptfTrom the washed coal and forced by means of a
pulsometer fc>fr£ft ffie supply cistern e. An -overflow pipe i is

arranged between
case of the pulsomete

It is estimated
washer cleaning 3IM.) to
To this must be
say $1,500,

The followin analys
washing :

two

isterns to prevent waste of water in
the, top cistern e,

:1 machinery complete, for a
not exceed $2,500.
eon and the timber work,
$4,0( m
are submitt^MpCThtfw its work in coal

RESULTS OF WASHING

Plant

Ash
Per Cent.

^ .

Sulphur
Per Cent.

r>i 1 r> f Unwashed..

11.20

2.03

Black Boy|Washed

3 84

1.46

{Unwashed .

9 35

1.18

Washed. .

4.60

.86

Unwashed..

5.95

1.08

Washed

3.60

1.00

ITT j f Unwashed

10 10

1 61

Westerton(^ashede

5 70

1.18

TTT j. A 11 j f Unwashed

15.40

1.14

West Auckland(Washed

3.70

.76

ox TT 1 > f Unwashed

11.10

1.92

St. Helen's[Washed

2 82

1 16

New Copley /Unwashed

11 28

1 50

Dusty "Coal \Washed .

3.83

.84

New Copley /Unwashed

14.75

1.61

Coarse-small \Washed

2.74

.78

In kindly furnishing the foregoing information in regard to this
coal-washing machine, Mr. H. S. Chamberlain, President of Roane
Iron Company, of Chattanooga, Tennessee, writes: "I came across
this machine in 1890 while on a trip in the north of England and

ft ft

u u

i Q <n

Section KL

17303— in

FIG. 27. PLAN OF LETHRIG WAS

PLANT AT DOWLAIS, WALES

17303— in

FIG. 28. SECTION or

> E A B OF FIG. 27

TREATISE ON COKE 101

was so struck with its simplicity and effectiveness that, after con-
siderable negotiation, I secured the agency for the machine in
this country and put one up at our colliery at Rockwood, Tennessee.
The calculation is made on 10 hours' work per day; that is, a 400-
ton machine will wash 400 tons of coal in 10 hours, but really will
do 25 per cent, more if pushed very little. "

In the foregoing description of the work of this coal-washing
machine, it is understood that the coal used is the "screenings"
made at the coal mine in preparing the several classes of lump,
egg, and nut coal for market. If the run-of-mine coal is used for
the manufacture of coke it will require the preparatory processes
of disintegration and washing.

THE LUHRIG WASHER, DOWLAIS, WALES

Figs. 27, 28, 29, and 30 will convey the general arrangements
adopted at the Rybnik Collieries in the location of the Liihrig coal
washer in connection with the coal mine and coke ovens at that
place

The plan shown in Fig. 30 is interesting, as it illustrates the
method of constructing these works to secure the most economy
in the several operations. The processes consist essentially in
receiving from the mine, on the platform or landing of the colliery
shaft, the run-of-mine coal. It is then passed over a 3-inch screen,
the large lumps going to market, the screenings being deposited
for further treatment in the washing section of the plant. This
slack or fine coal is then classified by revolving screens and washed
in the usual way. Large settling tanks are provided for the very
fine sludge coal, which is usually found valuable in the manufac-
ture of coke. Automatic arrangements have been made for storing
the washed coal, so as to permit its becoming somewhat dried
before being charged into the coke ovens. The plan also provides
for the direct and economical handling of the coal from the mine
until it is loaded into railroad cars for market or placed in the
washer for the coke ovens.

This, in common with other washing machines, will require
special arrangements to meet local conditions of coals to be treated.
It is claimed that by this process the washed coal will not contain
over 4 per cent, of ash at most, and that the tailings or refuse will
retain only 3 per cent, of coal. The cost of washing alone is given
at 1^ penny; in the United States the cost would be 6 to 7 cents.
The capacity of this washer can be enlarged to meet the largest
demands on its output.

Prof. C. Kreicher, of the Royal School of Mines, Freiberg, is
quoted as having approved of this method of washing coal.

Description of the Plant. — This arrangement has been rendered
more complicated owing to the machinery having to be erected on

102

TREATISE ON COKE

a long, narrow strip of ground, divided by an incline that had to
be arched over and also by provision having to be made for wash-
ing bituminous and steam coal separately.

The arrangement therefore comprises, two sets of systems, viz.:
(a) The system for washing bituminous coals; (b) the system for
washing steam coals.

(a) The System for Washing Bituminous Coals. — The bitu-
minous coal is brought to the Shephard machine, which existed
previous to the erection of the new washing machine, where it is
crushed by means of rolls a, Figs. 27 and 28. It is then elevated
by the elevator c1 into a revolving screen blt which divides it into
two sizes, viz., from f inch to 0 inch, and from f inch upwards.

The nut coal, from f inch upwards, is raised by means of another
elevator c2 into a second revolving screen 62 placed above the

mm^mi^^^m^ JSecUonGH
FIG. 29. SECTION ON LINE G H OF FIG. 27

Shephard washing machines d^ to d5. This screen divides the
coal into five sizes, which are washed each in a separate machine
of Shephard's. After washing, the nut coal is raised by an ele-
vator c3 into bunkers y, situated between the building for the
Shephard machines and the building for the crushers. From these
bunkers the bituminous nut coals may be discharged into wagons,
when required.

The fine bituminous coal from f inch downwards is transported
by a current of water along a trough to a revolving screen 66, sit-
uated in the building of the new washing machines erected by
Messrs. Evence Coppee & Company, Engineers, Cardiff, Wales.
This screen divides the coal into two sizes : from } inch to f inch,
and from 0 inch to J inch.

The coal from £ inch to f inch is washed in two feldspar machines
£14 and £ie» Figs. 27 and 28, placed immediately below the screen;

TREATISE ON COKE 103

and the coal from 0 inch to J- inch is conveyed in a trough by a
current of water to the pointed trough /2, shown on the plan and
situated in the adjoining room of the new building. It is here
divided into six sizes, each of which is washed separately in the
feldspar machines gt to ge placed next to the pointed trough.
The f-inch and upwards bituminous coal is sent from the elevator
raising the washed coal into a crusher. After being crushed, it
meets the small steam coal in a bunker situated below the crusher,
from which an elevator raises the coals, already partly mixed, to a
screw placed on the bunkers erected in front of the crushing depart-
ment. The screw o finally mixes the two coals and distributes
them into bunkers 15 and /6, from which ultimately the small
mixed coal is taken to the coke ovens.

(b) The System for Washing Steam Coals. — The steam coal is
also treated in the new washing arrangement. Arriving in wagons,
it is tipped into a bunker h in front of the new building, Figs. 27,
28, and 29, from whence an elevator 2\ raises it into a large revolv-
ing screen b3; this screen divides the coal into six sizes, one of
which is 0 inch to f inch, and five others varying from If inches
to f inch. The last five sizes are each washed separately in five
machines ]\ to /5, ranged on the second floor, from whence the
coal is run off on to reciprocating screens k1 to k4 for the purpose
of draining off the water. The dry coal drops into bunkers /j to /4,
from whence it may be sent away in railway wagons.

When, however, the five sizes are required for coking, the coal
is sent by a trough into a revolving screen b4 fixed next to the
crushers, from whence it is taken in a dry state, by means of a
screw, to the disintegrators x. The water draining off, and which
contains small coal in suspension, coming from the drying revolv-
ing screen and the reciprocating tables, returns to the feldspar
machines.

The fine coal from 0 inch to f inch from the large revolving
screen 63 enters another revolving screen 65, which divides it into
two sizes, | inch to J inch and } inch to 0 inch. The first size is
washed in two feldspar machines g13 and g15 situated in the large
revolving screen building, while the second and smallest is carried
by water in a trough to a pointed trough /t similar to that used for
dividing the bituminous coal. The pointed trough divides the coal
into six sizes, each of which is washed in separate machines g7 to
g16. All the fine washed coal in a feldspar machine runs together
into a large basin, from whence an elevator i4 with perforated
buckets raises it to the top of the bunker q. The small coal may
be bunkered if desired; if not, it may be sent by a transporter to
the crushing building, where it is remixed with the crushed bitu-
minous and steam coal.

The overflow of small coal from the small-coal basin runs first
into a long trough provided with a screw, and, as the small coal
settles, the screw brings back the coal to the common small-coal

104

TREATISE ON COKE

TREATISE ON COKE 105

basin, while the water runs into settling tanks or clarifiers m m.
These clarifiers are three long-pointed troughs provided with a
screw situated underneath. The dirty water, after having passed
through the clarifiers, returns to the well of the centrifugal pump t,
by which it is sent back and redistributed to the washers. The
mud settling in the clarifiers drops by gravity into the trough of
the screw, which transports it to the elevator is situated at one
end of the clarifiers, which raises the mud and drops it into bunk-
ers nl and n2.

The arrangement described above is washing 100 tons of coal
per hour.

REFERENCE TO THE DOWLAIS WASHING ARRANGEMENT

On Figs. 27, 28, and 29 a, are crushing rolls; blt revolving screen
for bituminous coal, 0 inch and J inch; 62, revolving screen for bitu-
minous coal, | inch and upwards; 63, revolving screen for steam
coal, 0 inch to f inch and upwards ; 65 and 66, small revolving screens
for fine coal;-64, revolving screen for drying nuts for coking; clt c2,
c3, bituminous-coal elevators; dlt d2, d3, d4, d5, Shephard's washing
machines; fl and /2, spitzkasten, for classifying fine coal; gl to g6,
washers for fine bituminous, from 0 inch to J inch, feldspar cases;
£14 to g16, washers for fine bituminous, from J inch to J inch, feldspar
cases; g7 to gl2, feldspar washers, for fine steam coal, 0 inch to
J inch; g13 and g15, feldspar washers for fine steam coal, J inch
to f inch; h, basin receiving steam coal from wagons; ilt elevator
raising steam coal to screen 63; i2, elevator raising mixed coal
to transporter for crushing; i3, elevator raising shale; *4, elevator
raising interstratified coal; *5, elevator raising slimes from clari-
ficator; ;\ to ;5, machines for washing coarse coal, f- inch upwards;
k, reciprocating screens; /j to /4, bunkers for washed nut coal;
/5 to /„, bunkers for fine washed coal, f inch and downwards;
m clarificator, or settling tanks; n, slimes bunkers; o, worm for
transporting coal to p^ to pa or to x; pl to p12, bunkers for crushed
washed coal to Coppee ovens; q, bunkers for interstratified coal;
fi» r2> fs» basins; s, driving engine for washing machines; t, centrif-
ugal pump; u, water pipes for supply to washers, etc.; v, small
engine for driving elevator and worm of clarifier; w, disintegrator
engine; .x, disintegrators; y, bunker for washed crushed coal delivery
in wagons; z, driving engine.

Results Obtained at Dowlais Washery. — The important ques-
tions to consider in coal washing are, generally speaking, three':
(1) to wash the coal clean, so as to remove all impurities, as far as
that is possible; (2) not to allow any coal to pass away with the
impurities; and (3) to wash the coal cheaply. As to the first
point, which is very important, it would be reasonable to know
the limit to which the impurity might be removed from the coal.
It was thought there was only one way of settling that question, and

106 TREATISE ON COKE

that was to ascertain, by analysis, the yield in ash of the pure coal
or the ash that could not be removed by mechanical means, as it
was certain that even the purest picked coal would still contain a
certain amount of impurities so intimately combined with the fuel
that even with the best system of washing it would be impossible
to remove it. In order to estimate the ash thus intimately com-
bined with the coal, the best way was to pick out small lumps, or
nuts, of pure coal and submit them to analysis by incineration.
The method was so simple that it might be carried out by any one
with a little practice, even without any knowledge of chemistry,
and would enable him to estimate the contents of the ash in pure
picked specimens of coal — a result that might be taken as the
absolute limit of the greatest amount of purity to be obtained by
washing. Some coals were so pure that pieces would not show
more than 1.5 per cent, of ash; others were so dirty that the ash
amounted to 10 per cent. Fortunately, the last class of coal was
scarce in this country.

The table on page 107 shows the results of 4 months' coal wash-
ing in the washing machine erected at Dowlais, and described in
the preceding pages.

In regard to the results of the Dowlais washing, as per details
submitted in full in this table, the average figures are typical of the
results of the 5 months' work. The steam coal, in its unwashed
condition, contained an average of 15.9 per cent, of ash and the
unwashed bituminous coal 25 per cent, of ash. The mixture of
these two coals in the proportion of half and half gave an average
of 20.4 per cent, of ash, and the mixed coal, after washing, con-
tained 5.9 per cent, of ash, while the coke made with that mixture
gave an average of 8.9 per cent. In the month of January the coke
made with that mixture of washed coal gave only 7.5 per cent, of
ash. These might be considered as fair average figures. During
the first 3 months after starting — viz., September, October, and
November, comprised in the table — the washing and sorting were
not as perfect as in the subsequent months; therefore, the figures
for the month of January were taken as being a fair statement of
the result.

Now, with respect to the second point that required consider-
ation, Viz., to conduct the operation so as not to remove any por-
tion of the free coal with impurities or with the shale itself. The
best way to ascertain that the shale is practically free of coal is
by taking a sample of the shale washed out, dividing it into two
parts; one part is then submitted to a careful washing in an ordi-
nary washing basin in order to remove all the particles of coal
from it, and the shale, after being dried, is then incinerated; the
difference between the weight of the ash and 100 will give the yield
of volatile matters. Now, take the other sample of shale and dry
and incinerate it ; the difference between the weight of the ash and
100 will give the yield of volatile matters in the shale plus that in

TREATISE ON COKE

107

Percentage of Ash

TOM?pKoui

!>. CO K3 O)
O 00 l> 00

SUIUSB^ J91JV
snouidmijg JJBJJ puB
tUBa^c; J{BJJ jo aan^xii\[

O5 00 Oi (M Oi

snouiuin^ig JIBJJ puB
uiBaic; JlBj-j jo am^xii^

JBOQ snouiuiniig

00 O <N 1-1 O
O IOO5 l> 1C

IBOQ UIB9}g paUSBAYUfl

(M COOi r-H O5

00 »O Tfi »O »O

Percentage of Ash in Washed Coal

•:

^o
"u

fe
c

Bituminous Coal

S^ S 2

id rjn id id id

00 »O(M I-H CO
iO iO CO lO lO

O5 Od CO iO 00
iO CO iO iO iO

OOO5 I-H <N O

co »d id cd co

G5 C<> -^ CQ T-H

CO l-H T-H 00

id co co co

Steam Coal

^ co <N' co co

CO CO (N* CO CO

I-H COO <N CO

•^ co co ^ co

iOC5<N 00 CO

COCOO5 -^ O

Tf coco -^ Tji

iooqi> 10 oo

"tf CO (N Tt CO

OiiOiM CO iO
COCOCO CO CO

In Nut-Coal
Washers

1
O

nnco^-; iO »H

•^

id ^ co ^ ^

iO Tf l>- 00 CO
•^ CO (N CO CO

O5oqt>- t^ <M

i-H

t>-t>-CO 00 CO

idco'id co Tjn

1884
September and October.
November
December

1885
January

Average

108 TREATISE ON COKE

the free coal contained in the shale. Deducting the result of the
incineration of the rewashed portion of shale from the last result of
incineration, the difference will show the free coal carried away
with the shale.

In the feldspar washery of the Coppee system, the free coal in
the shale varies from 1^ per cent, to 5 per cent. The yield in ash
in the shales varies not only from district to district, but from a
seam of coal to a seam of coal. However, we may state that,
according to many hundreds of analyses of the shales of South
Wales, the ash in them amounts to from 66 per cent, to 75 per cent.
Some Lancashire shales yield only about 47 per cent, of ash. The
cost of washing, including labor and all charges, except interest
on capital, does not exceed 3 pence per ton of washed coal.

The following are a few analyses of the Clifton and Kersley
small coal in an unwashed state — analyses that were made previous
to the erection of the washery :

PER CENT. OF ASH

Gannel coal contained 30 . 340

Doc mine coal contained 16 . 450

Pure picked nuts of cannel coal contained 8.200

Pure picked nuts of Doc mine coal contained 2 . 740

Mixing the two above coals in equal quantities, the

average ash in the mixture was 23 . 395

Average of intimately connected ash with nuts in the

mixture of equal parts was 5 . 470

After 3 months' washing, a few samples of small coal

taken and analyzed gave in average -. . 6 . 550

So that the washed coal differed from the absolutely pure coal
by 1.08 per cent, of ash only, which may be considered an exceed-
ingly satisfactory result.

LUHRIG WASHER, NELSONVILLE, OHIO

The following is a description of a Ltihrig coal washery for fine
coal screenings, designed and equipped in 1901 by the Link-Belt
Machinery Company, of Chicago, Illinois, for the Buckeye Coal and
Railroad Company, of Nelson ville, Ohio, that has a capacity of
100 tons per hour. The design was to assemble the screenings
from a number of coal mines in the Hocking Valley field to a con-
venient point, unload them, wash them, and send the cleaned coal
to market in fine sizes, known in the market as domestic egg,
No. 1 nut, No. 2 nut, No. 3 fine, and No. 4 fine.

The coal screenings were to be delivered either in hopper-bottom
or gondola cars. Hopper cars, it was believed, could be unloaded
on one track at the rate of 100 tons per hour, and track No. 1,
Figs. 31 and 32, was set apart for this purpose. Under this track
there was constructed a concrete hopper about 40 feet long and
holding a carload of coal. From this hopper, the coal was taken
to the elevator a by means of the right-and-left screw, b, as it was

T-T \cnqtne (

1 7303 ~i

FIG. 31. LtiHRiG WASHERY AT NEL

- .

i r i iiji ^

r;vt^-:t;:t -ttj^l

r _u _ .gri. i _ _ ^V _^^_Mir zp - -

"~rii1, l~ul£-I9-J

LLE, OHIO. (END ELEVATION.)

&;*.

..*...

» Track rtqoper
i

fvVV'^VV-^'-VVV-^'-
cinti- ------- =^ --=---- ---T*

i ^-^ r

17303—in

FIG. 32. LUHRIG WASHERY AT NE

VILLE, UHIO. (SIDE ELEVATION.)

TREATISE ON COKE 109

not found possible to unload 100 tons per hour on one track.
With the application of a screw unloader and an additional track,
No. 2, this difficulty was removed.

Elevator a delivers the coal into a pair of jacketed screens c, c
that classify the coal into three sizes of coarse coal and one size
of fine coal. The inner jacket, with l^-inch holes makes domestic
egg; the middle jacket, with 1-inch holes, makes No. 1 nut; the
outer jacket, with f-inch holes, makes No. 2 nut. The domestic
egg and No. 1 sizes are distributed into the respective nut-coal jigs
by means of the conveyers d, d while the No. 2 nut falls direct
into the nut-coal jigs. From the nut-coal jigs on the third floor,
the washed nut coals are delivered direct into their respective
bins by means of the bumping screens e, which are placed directly
over the washed-coal bins, draining some of the water from the
coal and allowing the clean nut coal to fall direct into the ship-
ping bin without further handling. A spray of clean, fresh water
thrown on the coal before it leaves the bumping screen brightens
it considerably.

The washed-coal bins are nine in number, and are arranged in
a row over the shipping track. There are two bins for each of
the three coarse coals, one for No. 3, one for No. 4, and one for
Nos. 3 and 4, mixed. An additional bin has been provided for
the refuse, which is loaded into hopper-bottom cars and used by
the railroad managers for filling. Each bin holds 30 tons and a
car of -nut coal can be loaded, one half from each of the two bins.
The nut-coal bins need never be less than half full, reducing the
breakage of the clean nut coal to a minimum.

The refuse from the jigs is gathered by the screw conveyer /,
raised out of the water by the perforated bucket elevator g, and
delivered direct into the refuse bin over the shipping track. The
water from the nut-coal jigs, drained out of the coal by the bumping
screens e, flumes the fine coal from the outer jackets of the screens
c, c into the fine-coal jigs h by means of the grading box i, which
hydraulically grades the coal to the jigs for better washing. From
h, the clean fine coal is flumed to the draining screen /, which has
£-inch holes in it. It not only drains the water from the coal, but
also screens out the No. 3, f-inch to J-inch sizes, from the No. 4 size.

The No. 3, from end of screen /, is lifted into its shipping bin
by means of the perforated elevator k. The ultimate refuse from
the bottom of the jigs is recovered by the refuse recovery screw m
and lifted into the refuse bin over the shipping tracks by the per-
forated bucket elevator n. The sludge, or No. 4 coal, being all
the coal below J inch, is recovered by the Luhrig sludge recovery o
and lifted into its shipping bin by the sludge elevator p.

The water is circulated by a 10-inch centrifugal pump q. The
power plant is located in a separate brick building from which
the power is transmitted to the washery by means of rope
transmission r. Two 66' X 18' boilers furnish the steam to a

110

TREATLSE ON COKE

150-horsepower double Erie automatic engine and to a small
electric-light engine. The screw conveyer 5 takes No. 4 washed
coal direct from the shipping bins to the front of the boilers.

The following table summarizes some approximate figures
regarding the operation of this plant:

Name of Coal

Size of Screen
Inches

Proportion
Per Cent.

Free Water
Per Cent.

Domestic egg

No 1 nut

1£ to 1

No 2 nut

1 to f

No 3 fine

f to 1

No 4 fine

1 to 0

Waste

The amount of free water was obtained by weighing a car of
wet coal as it came from the shipping bins and then allowing it to
stand on a siding to drain until, by repeated tests, it no longer
showed any appreciable loss in weight.

LUHRIG WASHERY AT PUNXSUTAWNEY, PENNSYLVANIA

The Liihrig coal washery, erected near Punxsutawney, Jeffer-
son County, Pennsylvania, is one of the large modern washers for
the cleaning of coal for the manufacture of coke. It has a capacity
of 75 tons per hour as designed and equipped in 1897 by the Link-
Belt Machinery Company, of Chicago, Illinois. The objects sought
to be obtained in this plant are: (1) To provide clean coal for the
beehive coke ovens; (2) to be prepared to ship clean nut coal for
fuel purposes if the market conditions make it desirable to do so.
Fig. 33, (a), (6), and (c), shows three views of the general arrange-
ment of the machinery and main timbers in the supporting struc-
ture, with many details omitted to avoid confusion of lines. A
raw-coal bin, not shown on the drawings, holding 2,000 tons, was
provided to receive the accumulation of coal from the mine, so as
to make mine and washery independent of each other to the extent
of 2 days' full run. In this bin or receiver the run-of-mine coal
is stored, after having been broken to nut-coal size by two Bradford
breakers. From this raw-coal bin the coal is taken as required,
by a Dodge chain conveyer, and placed in the raw-coal hopper a;
from this it is taken by the elevator b to the top of the building
and delivered into the triple jacket screen c. This screen has
jackets with 1^-inch, 1-inch, and £-inch holes, reading from within
out, making Nos. 1, 2, and 3 nut coals and a finer coal, which is
all that passes through the £-inch holes in the outer jacket. The
three sizes of coals are kept separate and are apportioned among
the seven nut-coal jigs d, according to their respective quantities.

— X. --V-
4VK

17303— in

FIG. 33. LtfHRiG WASHERY .

UNXSUTAWNEY, PENNSYLVANIA

TREATISE ON COKE 111

From these nut-coal jigs, the cleaned coal is flumed direct into
the six shipping bins Nos. 1, 1, 2, 2, 3, 3, in (a); the water being
drained from the coal by means of the bumping screens e. If this
nut coal is not to be shipped as fuel, but is to be used for making
coke, it is flumed to the second nut-coal elevator /, which has per-
forated buckets, and drains the water from the coal as it is lifted
to the Link-Belt coal crusher g. The fracture of the coal being
cubical and the slate interleaved in flat condition, this crusher
frees the slate from the coal, the product passing through the
screen h; the rejections from the screen, which has J-inch round
holes, are nearly all flat slate pieces and are discarded.

It will be noticed that the nut-coal jigs are on the third floor.
On the second floor is a row of twelve fine-coal jigs t — Luhrig
feldspar jigs. Six of these are used to wash the fine coal that is
passed through the holes in the outer jacket of screen c, while the
other six are used to wash the washed nut coal that has been
crushed by g and screened through the holes in h.

The clean coal from the twelve fine-coal jigs is flumed to the
draining screen i, which has ^-inch holes. The discharges from
the end of this screen are the final clean coal and are lifted by
means of the perforated bucket elevator / to the top of the
2,000-ton washed-coal draining bin k, into which it is distributed
by means of the Dodge chain conveyer /.

The slate valves in the nut-coal jigs d are so set as to reject as
primary refuse all pieces of coal that are contaminated with slate
or other foreign matter. This refuse is gathered from the seven
jigs by means of a screw conveyer m, and lifted out of the water
by the perforated elevator n and dropped into crusher o, which is
the same make as crusher g. From o, it is elevated by means of
the intermediate elevator p and screened by q. Here again flat
pieces of slate are separated and all that passes through the £-inch
holes in q is rewashed in the Luhrig feldspar rewashing jigs r.
These jigs are similar to the fine-coal jigs, but the relative areas of
plungers and screen surface are different. The clean coal recovered
by these jigs is lifted by elevator 5 into the rewashed-coal bin as
shown on (a). The final refuse that passes through the feldspar
bed in the fine-coal jigs / and the rewashing jigs r goes into the
refuse recovery u.

A great quantity of water is required about this plant for
washing the coal and refuse, but this water must be recovered and
used over and over. If allowed to run away, it would not only
require a large fresh -water supply, but it would carry away with
it a quantity of fine coal, as well as damage adjoining properties
by flooding them with fine coal and refuse. All the water used in
the washery, therefore, except such portion as is carried away with
the wet coal and dirt, is finally gathered into the sludge-recovery
tank. At v is an 8-ineh centrifugal pump taking its suction from
the near end of the sludge recovery, and the main stream of water

112 TREATISE ON COKE

is lifted to the nut-coal jigs and used in washing the nut coal. All
the water drained from the nut coal by e or / is used to flume the
fine coal "from the outer jacket of c into the fine-coal jig t. Some
additional water from the pump v being required, all the water
drained from the final washed coal by i and 5 flows into the pit at
the end of the sludge recovery tank.

This sludge recovery consists of a large tank 80 feet long,
11 feet wide, and 12 feet deep. At one end, in which stands the
sludge elevator w, the pit is 8 feet deep. In the bottom of this tank
there is a scraper conveyer having three chains and scrapers of the
full width of the tank ; this moves very slowly and scrapes all the
fine-coal settlings to the elevator pit. All the water entering
the sludge recovery does so at the pit end and is taken out at the
opposite end by the centrifugal pump. The fine coal thus settled
consists of that which escapes through the holes in screen i and
elevator buckets s, and is lifted by w and delivered into the coking-
coal bin by conveyer /, thus mixing it thoroughly with the coal
elevated by /. The water that has been used to flume the refuse
from the bottoms of the jigs flows to the refuse recovery u. This is
a Y-shaped tank in which a screw conveyer x gathers the settlings
to a final refuse elevator y, which has perforated buckets and
delivers the final refuse into its bin to be removed from the plant.
The water overflowing from the refuse recovery goes into the
sludge tank and is again used.

The table of analyses, on page 113, of coal before and after
washing, is taken from the experience of the manufacturers of the
Liihrig washers, the Link-Belt Machinery Company.

An excellent example of what can be accomplished through the
washing of coal is furnished by the results obtained at the Montana
Coal and Coke Company's plant at Aldridge, Montana, as described
by Mr. J. V. Schaefer in Mines and Minerals for December, 1903.
The coal there mined is very friable; and in a test, 74 per cent, of
the coal passed through a J-inch mesh sieve and contained 15.7
per cent, ash; 15.8 per cent, passed over a J-inch mesh arid through
a J-inch sieve and contained 25.6 per cent, ash; the 10 per cent,
that went over the J-inch sieve contained 40.8 per cent. ash. A test
of a sample of the coal that had passed through a ^-inch mesh
and over a J-inch mesh shows that 32 per cent, floated in a solu-
tion having a specific gravity of 1.31 and contained 7.2 per cent,
ash, while 68 per cent, sank and contained 41.5 per cent. ash.

This coal was washed in two jigs. As a result of the first
jigging, 61 per cent, of the mine product was obtained that was
suitable for coking and contained from 10 to 11 per cent. ash.
The refuse from this first jigging was rejigged, and from this
material 3 per cent, of the mine product was obtained as middlings,
which was used for fuel under the boilers at the plant and con-
tained 18 to 20 per cent, ash, while 36 per cent, of the mine product
was rejected as refuse and contained 60 to 68 per cent. ash.

TREATISE ON COKE 113

ANALYSES OF COAL BEFORE AND AFTER WASHING

Washery

Before Washing

After Washing

Ash
Per Cent.

Sulphur
Per Cent.

Ash
Per Cent.

Sulphur
Per Cent.

Alexandria Coal Co Greensburg Pa

10.60

8.60

37.04
12.88

9.48

9.19

18.21
21.75
9.65
31.08
25.60

7.56

16.30

25.30
15.80
18.74

38.00
18.00
13.77

16.30
25.00
5.63
4.69
5.41

14.29

1.139
1.30

3.53

.78

1.43

5.07

.77

.34

1.53
.57

1.90
3.34

1.05
.57

1.64
1.50
1.56

1.32

6.21

9.50
5.45

11.00
7.65

4.85

8.34

11.72
9.14
5.30
12.25
8.50

4.41

9.70

8.50
8.00
5.56

8.90
4.20
4.30

9.70
8.00-
2.25
3.25
4.63
6.24
5.72

.617

.850
1.030

2.870
.690

1.100

4.540
.480

.550

1.140
.400

.870
2.400

.890
.400

1.110
1.680
1.120
1.010
.820

Coke made from this washed coal

Rochester and Pittsburg Coal and Iron 1
Co Punxsutawney Pa /

Skagit Coal and Coke Co., Cokedale, Wash.
Central Coal and Iron Co., Central City, Ky.
New Ohio Washed Coal Co., Carterville, 1
111 No 1 mine ... /

New Ohio Washed Coal Co., Carterville, \
111 No 2 mine . . . . J

Cambria Mining Co., Cambria, Wyo
Dayton Coal and Iron Co., Dayton, Tenn.
Crows Nest Pass Coal Co., Ferriie, B. C. ..
Western American Co., Fairfax, Wash.. . .
Montana Coal and Coke Co., Horr, Mont .
Kanawha and Hocking Coal and Coke \
Co Harewood, W. Va J

Northwestern Improvement Co., Roslyn, \
Wash J

Rocky Fork Coal Co., Red Lodge, Mont...
Luhrig Coal Co Zaleski Ohio

Belt Mountain Mont

Wellington Colliery Co., Vancouver Is- 1
land new coal . . J

De Soto 111

Buckeve Coal and Railroad Co., Nelson- 1
ville' Ohio J

Roslyn Wash

Red Lodge, Mont.
Reserve mine Stein washer . . . ."

Caledonia mine, Stein washer

Dominion mine Stein washer

Coke from coal Stein washer

Alleghany coal Stein washer

Although the ash in this coking coal is still high, as compared
with some eastern coals, the coke made from it has to compete
with coal on which a high freight rate is paid, and it can therefore
be sold at a good profit in spite of the fact that 36 per cent, of the
coal mined must be rejected as refuse.

Mr. J. V. Schaefer says: "The loss of coal in the process was
not over J per cent., and taking into consideration the great quan-
tity of matter that had to be removed, I think these results are
remarkable, and, so far as I know, have never been surpassed."

The Stewart Coal Washer. — The Stewart type of coal washery
had its origin in the desire of Mr. E. A. Stewart, the patentee, to
design a plant that should be simple in its arrangement and

114 TREATISE ON COKE

operation, effective in its work, and at the same time have a large
capacity. The jig principle was decided on as the only device that
could be depended on at all times and under all circumstances to
give economical results: Instead of using a large number of small
jigs placed at the top of the building, Mr. Stewart adopted the idea
of using a few large jigs placed on the ground. Instead of sepa-
rating the coal into many sizes before washing, and keeping these
sizes separate throughout the process, a system that necessitated
the use of a multiplicity of elevators and conveyers, he designed
to wash the coal in mixed sizes and separate afterwards, if desired.
By placing the jigs on the ground he not only obtained solid founda-
tions for his jig tanks, but he was enabled to erect above the jigs
storage bins for unwashed coal, from which the coal could be fed
direct into the jigs without any intermediate handling, in this
way again simplifying the process, as it is absolutely essential for
the economical working of any washing process to have a regular
and continuous feed of coal to the machines. When these machines
are placed at the top of a building two systems of elevators are
required — one for elevating the raw coal into the storage bins and
another for elevating out of the storage bins into the washing
machines.

In order that the coal could be washed in mixed sizes effectively,
Mr. Stewart designed the jig that bears his name, Fig. 34. In this
jig, the downward suction that always exists to a certain extent
in all eccentric-driven jigs is overcome by a peculiar arrangement
of valves in the water-supply pipes. Very remarkable results
have been accomplished with the use of this jig. Its first marked
success was achieved in Southern Illinois. From there, Mr.
Stewart moved to Birmingham, Alabama, where the Stewart
washer very soon demonstrated its superiority in washing the
Alabama coals.

In Fig. 34, a is the unwashed-coal storage bin, of any size that
may be desired, holding the coal of all sizes, as the coal is not
screened or sized prior to washing, b is a sliding cast-iron gate,
operated by rope or lever, that admits the coal from a through c
into d. c is a sheet-iron housing fastened to the jig box d and
extending into the box. This is to force all coal going through c
under the water-line, so as to prevent any fine dust from floating on
top of the water and passing out over the end of the jig without its
having become subjected to the action of the water, c? is a jig box,
about 5 feet X 7 feet, that is fitted into the jig tank e by metal
plates on the four sides of jig tank and on jig. This jig box has a
reciprocating movement and is worked by double eccentrics / and g
keyed to shafting, lying parallel and geared into each other to run
at the same speed, The jig box is hung from /, g by eight rods h.
The coal after passing through c is at once immersed and goes
through a complete disturbance from eight to ten times before it
reaches the point of discharge for the coal / and for the slate k.

TREATISE ON COKE

115

The box has, in the bottom, perforated plates that slope to the front
end where there is a sliding gate /. The capacity of the jig is 20 to
40 tons of coal per hour. The jig tank e is built in size to suit the
jig box so as to allow it to swing free. The tank is bushed in on
four sides with iron plates to fit squarely against the same character
of plates on the jig box, giving the result of a practically tight
joint, but at the same time giving the jig sufficient play so that it
can be moved up and down by the eccentrics / and g hung on the
two pieces of shafting just over the jig. As the jig box goes down,
the water is forced through the perforations in the plates with

FIG. 34. STEWART JIG

sufficient force to carry the coal of a certain specific gravity up
and over the lower end of the jig, the water being sluiced through
an open trough to the settling tank, or basin, o\ the speed of the jig
depends entirely on the specific gravity of the coal that is being
worked.

The slate gate, or refuse discharge, / is raised and lowered
at will- by the lever m. The opening at k is adequate to pass a
4-inch cube, and is the entire width of the jig; the lever m is
fitted to a radius of a half circle with slot to accommodate the open-
ing and shutting of the gate /, and is fitted with handscrew so as
to enable the setting of this gate at any height. The operator of
the jig, after becoming familiar with his coal and the amount of

116

TREATISE ON COKE

I J

Carter:
Ash,
30 Per Cent.
Sulphur,
06 Per Cent.

,
0.35 Per Cen
Sulphur,
.433 Per Cen

iCO O
0005 05

10 co co

CO l>iO

CO TP iO

ioc o

»o cc 10

00 00 00

iO"* 00
<M CO

CO 00

r-> CO t>

_„ Ol OS
"* OS O

OS Oi OS

CO CO

T-lOS t>

OS OS OS

000

CO CO CO

,-1 OS-tf

O5 OS t^

'O(M OS

<N<N CO

—i 1C 00

impurities it carries to the ton, very
readily learns about the distance to
leave his gate open, necessarily
making the jig as near absolutely
automatic as any jigging process
that has ever been developed.

The coal, after having been sepa-
rated from its impurities, passes over
the top of the jig box d and out to /,
into what is termed the settling
basin n, where it is allowed to set-
tle to the bottom, there being
very little disturbance of the water
in n ; thence it is delivered by a per-
forated bucket elevator to any point
desired.

The next important feature is
the water circulation, the water being
used over and over again. The only
fresh water required is the water that
is actually consumed • or absorbed
by the coal in the process of washing.
The water from the basin n, which
overflows from the top into a well
is carried by any means desired —
commonly a centrifugal pump on
account of capacity and low duty—
into what is termed the supply tank
o, thence through the opening p into
tank e to valve q.. As the jig box d
moves up, the valve being a cast-
iron swinging check, admits the
water through p into e and fills
the vacancy caused by the upward
motion of d. On the downward
motion of the box d, the valve q
closes and the water is forced
through the perforated bottom of
the jig box d and the same process is
gone over and over as has been cited.
. The gate in front of the jig box
is left open at a certain point, which
is governed by the amount of slate
and impurities to the tonnage of coal
being washed. The down motion of
the jig loosens the slate bed in the
bottom and works it toward the
front, or discharge, side, where it is

TREATISE ON COKE

117

118 TREATISE ON COKE

discharged into the jig tank e under the jig box and is carried
by a chute or hopper to a point where it is taken up by the
refuse elevator and carried out. The peculiar arrangement of
this jig box with the perforated bottom fitted into the tank
gives a very sensitive arrangement with which the jig distin-
guishes the difference between materials of a very close specific
gravity; for instance, in one case where the coal varies in specific
gravity from 1.29 to 1.37, the bony coal from 1.38 to 1.56,
the shale from 1.40 to 2.04 and the slate from 1.70 to 3.40, an
average from forty-nine samples of run-of-mine coal shows the
coal 82.6 per cent., bone coal, 11.4 per cent.; shale, 4.5 per cent.;
slate, 1.5 per cent. The following is the result of eleven samples
taken from the washed product: Coal, 92.9 per cent.; bone,
5.3 per cent.; shale, 1.8 per cent. The refuse or tailings show
coal 3.8 per cent.; bone, 18.2 per cent.; slate and shale,
78.9 per cent. In another case where there is considerable
fireclay to contend with, mixtures of coals from three different
places were washed. The results of these washings are given in
the table on page 116.

Fig. 35 shows. a section and plan, and Fig. 36, a photograph of
a Stewart washery of one jig; for convenience the elevators are
shown in a straight line. Although the washer appears very rigid,
on the contrary it is a very flexible machine, and can be made to
suit almost any surroundings on account of the fact that the dry-
coal elevator can be located on any one of three sides of the washer.
The same conditions apply to the washed-coal elevator ; it also
can be located on any one of three sides. The part of the washer
designated as the settling tank can be removed to any point where
it can be located far enough below the level of the jig so that the
water may carry the coal to it, but for convenience sake it is
located very close to the jig tank.

The illustrations show the washer located on approximately
level ground. The coal if screened, or if using run-of-mine, is
delivered at a point where the unwashed-coal elevator will carry
it up and deliver it into the unwashed-coal bin; thence, through
openings over the jig box, it is allowed to empty into the jig box
as freely as is desired.

The Stewart system of coal washing does not require that the
coal be sized prior to the washing, and there are quite a number
of cases through Illinois where it is being used very advantageously
for washing coal for fuel purposes, the coal being sized after having
been washed to take care of the fine dust and breaking of nut and
pea coal, which necessarily goes on during the process of washing.
Under those circumstances it is possible still to maintain the service
of a general loss of less than 5 per cent, of free coal in the process
of washing. The power required for operating the Stewart washer
is approximately 10 horsepower per jig. Where there is any
screening or extra conveying machinery attached to the washer

TREATISE ON COKE

119

the necessary horsepower required must be added to the power unit.
The amount of labor required to attend to the washer is, in case of
more than a two-jig washer, two men only, requiring the ordinary
skill of an engineer around a mine. One man on the platform of

the washer can attend to a five-jig washer, washing 1,800 tons per
day of 10 hours, thee ngineer looking after the engine and oiling up
the other machinery; the power required is about 100 horsepower.
The cost of construction is a matter hard to determine, as it
depends entirely on the surroundings and the length and capacity

120

TREATISE ON COKE

of the elevators and the additional machinery required to dispose
of the coal.

This system has become quite popular throughout the Southern
States, and the cost of this washer is about $20,000.

The following is a report of the results obtained with a Stewart
washer at the Sayreton mines of the Republic Iron and Steel
Company, made by the chemist of the company, Mr. David Hancock:

"Our run-of-mine coal, as shown by the average of forty-nine
samples taken in the mine, is made up as follows:

Coal

Bone coal . .

PER CENT.
, . 82.6
11.4

Shale

Slate from partings ,

PER CENT.
. . 4.5
1.5

"The average specific gravity of these portions I give below,
showing also the extent of variations in parenthesis:

Coal 1.33 Specific gravity (1.29 to 1.37)

Bone 1 . 45 Specific gravity ( 1 . 38 to 1 . 56)

Shale : 1 .60 Specific gravity (1 .40 to 2.04)

Slate 1 . 95 Specific gravity (1 . 70 to 3.40)

"The next table shows the results of 10 day's washing and is
the average of eleven samples:

WASHED PRODUCT PER CENT.

Coal 87.9

Bone 10.3

Shale 1.8

Slate.. .0

TAILINGS . PER CENT.

Coal 3.8

Bone 18.2

Slate and Shale 78.9

"The work is even better than here shown for the reason that
it is the lighter varieties of bone and shale that remain in washed
coal and the heavier varieties that go to the slate dump. This
point is well shown by the following analysis:

PER CENT.
WASHED PRODUCT OF ASH

Coal 7.50

Bone 18.00

Shale 33.40

PER CENT.
TAILINGS OF ASH

Coal 11.90

Bone 27.90

Shale.. . 55.00

"I give finally two representative analyses of our coke, one
before the washer was installed and one showing the coke as it
now is:

Unwashed

Washed

Volatile

3 65 per cent

2 75 per cent

Fixed carbon . . .

76.71 per cent

82 55 per cent

Ash

18 85 per cent

Sulphur

79 per cent

121

122 TREATISE ON COKE

" I have inspected hundreds of cars of Sayreton washed coal and
have never yet found a piece of slate of higher than 1.70 specific
gravity, although Sayreton run-of-mine carries an average of
40 pounds per ton of heavy slate of this character."

Very truly yours,

DAVID HANCOCK, Chemist.

STEIN AND BOERICKE WASHERY

Since 1895, the Stein washer has been built by the firm of Stein
& Boericke, Limited, of Primos, Delaware County, Pennsylvania,
and during this time they have made many improvements in its
design. In order to give a clear idea of the extent of these
improvements a description of one of the more modern plants
designed by this firm is here given. We 'have selected for this'
purpose the 1,500-ton plant of the Jamison Coal and Coke Com-
pany, of Greensburg, Pennsylvania, at their No. 2 works. The
plant, as it stands, is practically fireproof. The tipple is of the
most modern design, is constructed entirely of iron and steel, and
stands over a raw-coal bin of similar construction and having a
capacity of 500 tons. All the buildings are of massive brick con-
struction and are covered with terra-cotta tile roofing supported
by steel roof trusses, the roof trusses also being made heavy enough
to carry all the main shafting. The storage bins for washed coal
are of steel lined with brick made impervious to water. Fig. 37
gives a general idea of the outward appearance of the plant and
Fig. 38 shows a plan and elevation. The washing plant has a
capacity of 1,500 tons of raw coal in 10 hours and is designed for
handling either slack coal or run-of-mine, but as the tipple has
about double this capacity, the washing plant is supplied mainly
with the coal passing through a 3-inch bar screen, the lump coal
thus prepared being loaded directly into the cars by means of a
chute. The coal for the washer passes directly into the tooth
crushers a, alt where it receives its preliminary preparation for the
washing plant. From these crushers, the coal drops directly into
the raw-coal bin, from which it is drawn by means of an auto-
matic feeding device through the dampers c, from which the coal is
delivered by conveyers d, d^ to elevators e, el ; all elevators handling
the dry coal are mounted on steel frames to eliminate danger from
fire. From elevators e, ev the coal passes into the sizing screens /, flt
the particles too large for treatment in the washer falling directly
into the special crushers g, which are of such construction as to
reduce all coal and also flat and irregularly shaped slate to the
desired size without any subsequent handling. The coal thus pre-
pared is delivered by elevators h, h to the washing machines il to ilo,
on which the clean coal is separated from the slate and pyrites or
other impurities, and from which it is floated to the draining
elevators j, jlt from which it is distributed by conveyers k, k1 into

TlT

Bfack&mifh Coa/J3i
Load /no

Tfp]p/e

17303— in

FIG. 38. PLAN AND SECTION OF WASHERY OF JAMISOI*

P=>/an

73i Section C fo D ToE

A:, AND COKE COMPANY, GREENSBURG, PENNSYLVANIA

TREATISE ON COKE 123

the storage tanks /, lv The slate and other impurities are received
from all the jigs by elevator m, .which delivers the same to the
jig n for rewashing, in order to recover any particles of coal that
would otherwise be lost with the slate. The final slate passes into
the settling tank o and thence by means of an elevator p to a slate
bin q, from which it is carried away on cars. There is also pro-
vision made for diverting such washed coal from the washing plant
as is suitable for blacksmith purposes, to the blacksmith-coal bin t,
from which it may be loaded into cars. Each of the washed-coal
storage tanks /, l^ has a capacity of one day's run of washed coal
and is provided with drainage canals in the foundations; the coal
thus properly drained is taken as desired through dampers u
by conveyers v and elevators w, wl to the bin x from which the lar-
ries carrying the coal to the coke ovens are charged. The water
from the entire plant is gathered in the settling tanks y, y^ and
the clarified water is sent to the centrifugal pumps z^ z2, z3 to be
again circulated through the plant. The settlings in y, y1 are
removed by the conveyers y2, y3.

The machinery used for the preliminary crushing is driven by
a separate engine, not indicated on the sketch, thus permitting
the mine and washer to run independently of each other. The
machinery delivering the washed coal from the storage tanks to
the larries is also run by a separate engine, enabling the larries to
be charged at any time irrespective of the operation of the mine
or washer. All the machinery in the plant is very accessible and
has been kept on the ground floor, as also the storage tanks and
raw-coal bin, which, as will be readily understood, is far more desir-
able than to have these parts of the plant supported on trestle work
or in a high building. Cement floors are used throughout all build-
ings, which greatly facilitates the work of keeping the plant clean.

Mr. John M. Jamison, president and treasurer, kindly gives
the following information as to the cost and work of this washery:
(1) The cost of the washer plant designed to wash 1,500 tons of coal
in 10 hours is, in round figures, $65,000. We might add in expla-
nation that our plant was built at a time when high prices on all
material as well as labor prevailed. (2) The percentage of. impuri-
ties removed from our coal in washing .is approximately 4 per cent.
(3) Our experience in washing coal leads us to the conclusion that
10 cents per ton of 2,000 pounds is a reasonably safe estimate to put
upon the cost of washing coal ; this, of course, includes all the waste.

BAUM WASHER

The Baum Washer, Fig 39, is one that washes from 0 inch to
3J inches without preliminary classification. In its general con-
struction, the washing machine on the Baum system is similar to
that of the well-known pulsating washers, with much larger dimen-
sions, but the essential difference is that the pulsating motion is

124

TREATISE ON COKE

obtained by the action of a compressed-air, 4-foot water gauge,
which acts on the surface of the water in compartment a, in such

a manner that the movement is more elastic, but nevertheless
more energetic, than that obtained by a piston. The pulsa-
ting motion in the front compartment of the washing machine is

TREATISE ON COKE 125

quicker in the upward than in the downward movement. This is
effected by a constant inlet of water into the compartment a at b
and c. The pulsating motion combined with the movement of
the water running through the washer is such that the coal when
passing into the front compartment of the washing machine on
the top of the sieve d, df and going from e toward / is classified
in layers according to specific gravity, the heavier particles sink-
ing to the bottom. The lower layer, composed of dirt and shale, is
mechanically taken out at d and df through apertures, the height
of which is regulated by levers g. After having passed through
these apertures, the shale has to pass over a dam, the height of
which is regulated by means of levers h. Having passed through
the apertures d and dr (see the arrows on the drawing), the dirt
falls to the bottom of the washing machine through the openings i
and i' . From there it is taken by two Archimedean screws / and
an elevator k with perforated buckets to allow the water to run off.

The admission and exhaust of the compressed air are regulated
by sliding valves / actuated by the eccentrics m. These valves are
situated between the pipe n, conveying the compressed air, and the
compartment a.

The coal is introduced, by means of a current of water, into the
front compartment of the washing machine at e. The water neces-
sary for the washing process is clarified and carried by the pipe o
that introduces it at b and c.

Classifying Drum. — The exit of the washing water and of the
washed coal is effected at / through a trough that leads the whole
to a classifying drum of large diameter, and with superimposed
sieves where the screening is facilitated by a current of water that
forces the coal through the holes of the different sieves of the
drum; this peculiarity explains the good results obtained by this
apparatus. The drum classifies into as many sizes as may be
desired. Each size of coal is then led through troughs to the
bunkers for loading into wagons, after having received a quick
rinsing with fresh water and a passage over metallic gauze, which
allows the water to run off.

Rewashing of Fine Coal. — The fine coal under, say, £ inch is
taken with the washing water underneath the classifying drum by
a centrifugal pump that sends it to a washing machine similar to
the one described above, where it is washed again before being sent
to the draining conveyer.

Separation of Intergrown Coal. — If the quantity of coal contained
in the intergrown coal and dirt is only insignificant, the intergrown
coal is allowed to go away with the dirt. If, however, the quantity
is important, the intergrown coal is separated from the dirt, in
which case the coal, after having passed through the first washing
machine, is sent to a second washing machine similar to the first,
in which the lower layer will be formed by the intergrown coal,
which is recovered as described above.

TREATISE ON COKE 127

Separation of the Dirt Out of the Intergrown Coal. — It is some-
times advisable to crush the intergrown coal in order to effectively
separate the dirt from it ; in that case the crushed intergrown coal
is mixed with the fine coal before it enters into the last washing
machine.

Draining Plant. — The draining plant, Fig. 40, is able to reduce
the added moisture in the coal to such reasonable percentage as
may be desired; at the same time, it clarifies the washing water
by extracting a great part of the slurry by filtration through a
constantly renewed layer of fine coal. This draining plant consists
of an extremely strong conveyer, carrying about 2 tons of coal per
yard. The conveyer is made with perforated plates a, hinged
one to the other, and carrying on the middle a double vertical
partition b of perforated sheets, strengthened with angle irons, and
slightly separated from each other to allow the water to run between
them; the two upright sides c and d are also perforated. The con-
veyer thus presents an aspect%of a series of boxes hinged one to the
other in the middle of the bottom.

The washing water comes with the fine coal on especially
arranged swinging sieves of metallic gauze, which, as indicated in
Fig. 40, allow the water, the slurry, and the very fine coal to pass
through, while the coarser coal slides down to the conveyer at e.
The finer coal and the slurry, separated as just mentioned, then
fall on top of the coarser coal from / to g. The coal is now in the
best condition for draining.

As the conveyer moves, it passes over the supporting rollers h,
the distances and the difference of height between which are calcu-
lated so as to let the conveyer bend under the load of coal between
one roller and the other. The effect of this sagging of the conveyer
is to press the coal between the vertical partitions b when it arrives
between the rollers, or above the lower rollers, and to open these
partitions one from the other as it arrives above the higher rollers.
The coal is in this way submitted to a process of pressure and
expansion that compels the separation of the water from the coal.
This water, in passing through the layer of coarser coal at the
bottom of the boxes, leaves a great part of the slurry on the drain-
ing conveyer. It is afterwards recovered at i, and sent through
especially designed settling tanks insuring its thorough clarification.
After clarification, the water is used over again in the washer.

Regulation of Moisture. — The percentage of water left in the
coal may be regulated by the speed of the conveyer, which has a
length of about 22 yards, and generally a speed of about 8 inches
per minute. If it is run more rapidly, the percentage of water is
larger, the coal having thus less time for draining, and vice versa.

Settling Tanks. — The settling tanks, Fig. 41, are established in
such a manner that the slurry still contained in the washing water,
after its passage through the draining conveyer, is automatically
and continuously recovered. In the latest plants there is only one

128

TREATISE ON COKE

settling tank of large diameter (33 feet diameter and 39 feet deep) ,
which is constructed in iron and supported by a brick tower out-
side the washer building. In some plants, the settling tanks are
placed inside the washer building on the same floor as the coal
hopper. Their object is always the same, facilitating the deposit

of the slurry by a sudden stop-
page in the speed of the current
of water.

The tank is the shape of a
cone, with the point downwards.
The water containing the slurry
is pumped through the pipe a,
Fig. 41, at the point b. It meets
the shield c and is then compelled
to cross the tank from the cen-
ter to the circumference, and
consequently with a speed de-
creasing in geometrical progres-
sion, before it falls into the
gutter d that surrounds the tank.
The water is thus recovered in
a clarified state in this gutter,
and is taken away by the pipe e
to the washer. The slurry fall-

Fio. 41. SETTLING TANK ™% tO the bottom of the tank is

continuously extracted in the

form of a liquid mud through the pipe g, which takes it again to
the draining plant if it is clean, and where it remains with the fine
eoal; or, if it is too dirty, it is sent into tanks of small area out-
side the washer, where it is collected and used when and where
the colliery finds it advantageous.

A Baum Washing Plant. — The coal washer, Fig. 42, erected at
Gladbeck, Westphalia, may be considered as a standard washer on
the Baum system. The coal is brought from the screening plant a
through jigging screens b passing everything under 3 inches into
the hopper c. It is then lifted by an elevator d to the top of
the washer building. It receives at e a current of water that
pushes it into the first washing machine /. The shale falls to the
bottom of this washing machine and is caught by an elevator with
perforated buckets g, and dropped along chutes into the hopper h.
The washed coal is then conducted to the classifying drum it
which classifies into five, or as many sizes as may be desired. Each
size is delivered into hoppers / by means of chutes k and spirals,
which take the nuts without breakage up to the loading hoppers,
each having a capacity of 50 tons.

The fine coal from 0 inch to £ inch falls with the washing water
into a centrifugal pump /, which lifts it into a second washing

'^\ * ? '. • f

17303— in

FIG. 42. WASHING PLANT ON BAU

AT GLADBECK, WESTPHALIA

TREATISE ON COKE 129

machine m, where it is again washed and the last traces of fine dirt
extracted. The dirt is lifted by an elevator with perforated
buckets n and sent down to the hopper h. The fine coal leaving
the second washing machine is carried by the washing water to
the draining band o, which delivers it with the desired percentage
of moisture into the hopper p, which has a capacity of 200 tons,
where it is spread by means of Archimedean screws. In some
plants this fine coal is crushed at the end of the draining band by
a disintegrator situated above the bunkers p.

The washing water undergoes a second clarification in the
settling tanks q in the washer building. The slurry continuously
extracted through the bottom apertures r is conducted in the
shape of a liquid mud to the centrifugal pump s, which pumps it
again on to the draining band at t. The clarified water is pumped
through a centrifugal pump and sent back to the washer. The
settling tanks can be replaced by the one previously described and
placed outside the washer building. Such an arrangement gives
more room for the fine-coal bunkers. The compressed air is pro-
vided by the rotary blower v.

The washed sized coal is loaded directly into the railway wagons by
the chutes w, provided at % with rinsing apparatus, and the washed
fine coal is either loaded directly into the railway wagons or into the
larries y, situated at the level of the top of the coke ovens. All
the motors of this washer are electric, having a total power of 140
horsepower. This washer deals with 100 tons per hour of raw coal.

Washer for Fine Coal. — In cases where it is only required to
wash fine coal without sizing, the arrangement of the plant is as
shown in Fig. 43. The coal is brought to point a either by means
of an elevator or by a creeper coming direct from the screening
plant. It meets at a a current of water that pushes it into the
washing machine 6, suitably constructed to wash fine coal only,
say, under J inch or f inch.

The dirt falls, as explained previously, to the bottom of the
washing machine, where it is taken by an elevator with perforated
buckets c and sent from there into the dirt wagons d standing
alongside the building. The washed coal is then carried along
with the water on the draining band e and delivered dry at /. At
this point, the coal may either be loaded directly into the railway
wagons or may be delivered by the elevator g shown in dotted lines
on the drawing, which takes it through the disintegrator and, by
means of scrapers h, into the coal bunkers.

The water, having undergone a first clarification through the
draining band, is compelled to cross the settling tanks i through
their full length, where it drops the slurry, which is continuously
pumped back on to the draining band by a centrifugal pump /.
The clarified water is pumped at point k by the centrifugal pump /
and sent back to the washer.

130

TREATISE ON COKE

The compressed air is provided by the blower m.

The power for driving may be either steam or electricity, and
varies from 40 to 60 horsepower according to the size of the plant.
The engine or motor is in the engine room n, together with the

v^rf / // £?,
yx_/__y/

I r •

— _ _«~^_ _j^-_ -r»^_

FIG. 43

different pumps. The building, partly supported by cast-iron
pillars, is of brickwork for the first story, and above the first story,
of iron filled in with brickwork.

This very efficient washing plant is made in three different
sizes, to treat from 20 to 40 tons of coal per hour, and can be erected
and started to work within six months. Above that capacity
some alterations are made to the plant.

CHAPTER IV

HISTORY AND DEVELOPMENT OF THE COKE INDUSTRY

History. — Authorities are not in harmony as to the time of the
beginning of coke manufacture in England. In 1735, Darby is
reported as using coke successfully at Coalbrookdale, in Shrop-
shire; but little was accomplished, however, until 1750, when its
use became extended as a blast-furnace fuel. Evidently the same
economic conditions that subsequently expanded the use of coke
in the United States of America had their earlier force in England,
for the scarcity of wood for making charcoal and its increasing
cost forced iron manufacturers to search for and use a less expen-
sive fuel. The late Mr. Joseph D. Weeks has called attention
to the fact that from the abundance of wood for making charcoal
in the United States and the encouragement given to the exporta-
tion of charcoal metal to England, it is quite improbable that
much, if any, coke was manufactured prior to the Revolution.

In May, 1813, an advertisement appeared in the Pittsburg
Mercury, indicating that John Beal, an English emigrant, who
possessed the knowledge "of converting stone coal into coak,"
would, under certain conditions, communicate the same "to pro-
prietors of blast furnaces." It is not on record whether this offer
led to the introduction of the manufacture of coke in America.

Shortly after this, however, in 1816-17, Col. Isaac Meason
built the first rolling mill, west of the Alleghany Mountains, to
puddle iron and roll it into bars, in Fayette County, Pennsylvania;
this mill went into operation in September, 1817. Shortly after
this time, general attention was directed to the rapid disappear-
ance of the forests of Pennsylvania, accompanied by the discovery
of large deposits of coal, all pointing to the necessity of its manu-
facture into coke for use in the growing iron industry.

In 1825, the acting committee of the Pennsylvania Society for
the Promotion of Internal Improvements sent Mr. William Strick-
land to England, as their agent, to study various subjects relating
to internal improvements, and to investigate the methods employed
in the manufacture of iron. His letter of instruction was as follows :

"Attempts of the most costly kind have been made to use the
coal of the western part of our state in the production of iron.
Furnaces have been constructed according to the plan said to be
adopted in Wales and elsewhere; persons claiming experience in
the business have been employed, but all has been unsuccessful.

7 131

132 TREATISE ON COKE

In large sections of our state, ore of the finest quality, coal in the
utmost abundance, limestone of the best kind, lie in immediate
contiguity, and water-power is within the shortest distance of
these mines of future wealth.

"The prices which are obtained for iron on the western waters
are double those of England, the demand is always greater than
the supply, and thus nothing but knowledge of the art of using
these rich possessions is wanted.

"We desire your attention to the following inquiries on the
subject of the manufacture of iron:

"1. What is the most approved and frequent process for coking
coal, and what is the expense per ton or caldron?

"2. In what manner are the arrangements or buildings, if
any, constructed for the coking of coal, obtaining drawings and
profiles thereof?

"3. Are there different modes for coking coal ; and if they have
any difference in principle, what are they?

"4. In what manner are the most approved furnaces for the
smelting of ore constructed ? Drawings and sections of the same to
accompany the information that may be obtained upon this inquiry."

Mr. Strickland reported intelligently, with full drawings, illus-
trating the methods of coke making and the construction of blast
furnaces for using this new fuel.

As these investigations were completed in 1825, it is inferred
that coke had been in use before this time. A paragraph in the
history of Fayette County refers to the use of coke in the Alleghany
furnace in Blair County in 1811.

Mr. James M. Swank, general manager of the American Iron and
Steel Association, Philadelphia, suggests that the early efforts in the
use of coke in blast furnaces were made in mixtures with charcoal.

In 1835, the Franklin Institute of Pennsylvania offered a pre-
mium of a gold medal to "the person who shall manufacture in
the United States the greatest quantity of iron from the ore during
the year, using no other fuel than bituminous coal or coke, the
quantity to be not less than 20 tons." In the same year, Mr.
William Firmstone was successful in making good gray forge iron
for about 1 month at the Mary Anne furnace, in Huntingdon
County, Pennsylvania, with coke made from Broad Top coal.

In 1837, F. H. Oliphant made about 100 tons of coke iron at
his Fairchance furnace, near Uniontown, Fayette County, Penn-
sylvania; and in the same year coke was successfully used in the
Lonaconing furnace, Frostburg, Maryland.

These early efforts in the use of coke in blast furnaces were not
very successful. Probably this came from the imperfect methods
of making coke and the insufficient blast to the furnace. The
latter was, perhaps, the most retarding cause in the early efforts
in smelting pig iron with coke. While these experimental tests in
the use of coke were carried forward in Pennsylvania and Maryland,

TREATISE ON COKE

133

other states were also making efforts in the same direction. Coke
did not come into use rapidly. In 1849, Prof. J. P. Lesley failed
to record a single coke furnace in blast in Pennsylvania. In 1856,
however, he reported 21 furnaces in blast in Pennsylvania and 3
in Maryland using coke.

The early history of coke making in the Connellsville region is
involved in some obscurity; but Colonel Meason used coke at his
refinery in 1819. In 1841, two carpenters, Provence McCormick
and James Campbell, united with a stone mason, Mr. John Taylor,
in a coking enterprise. The mason was to build the coke ovens and
the carpenters would construct the arks to convey the coke by
river to market at Cincinnati. Two ovens were built about 10 feet
in diameter. The coal charge was about 80 bushels. In the spring
of 1842 enough coke was made to load two boats 90 feet long,
about 800 bushels each. These were taken to Cincinnati, but the
demand was trifling and the parties, losing heavily in the enterprise,
became disgusted with the outlook for marketing coke. This was
the beginning of the manufacture of coke in the great Connellsville
field, which now sends to market annually over 14 millions of tons.

The growth of the coke industry was undoubtedly greatly assisted
by the excellent product of Connellsville, but the manufacture
struggled along up to 1880 without impressing its value as of suffi-
cient importance to give it a place in the statistics of the products of
the industries of the United States. It has now attained a position
and magnitude of prime importance in all metallurgical operations.

The following table will show the number of coke establish-
ments in the United States, indicating the growth of the manu-
facture of coke from 1850 to 1903.

STATISTICS SHOWING DEVELOPMENT OF COKE INDUSTRY

Year

Number of
Establish-
ments

Year

Number of
Establish-
ments

1850

Census Year

1890

December 31

253

1860

Census Year

1891

December 31

243

1870

Census Year

1892

December 31

261

1880

Census Year

149

1893

December 31

258

1880

December 31

186

1894

December 31

260

1881

December 31

197

1895

December 31

265

1882

December 31

215

1896

December 31

341

1883

December 31

231

1897

December 31

336

1884

December 31

250

1898

December 31

341

1885

December 31

233

1899

December 31

343

1886

December 31

222

1900

December 31

388

1887

December 31

270

1901

December 31

423

1888

December 31

261

1902

December 31

456

1889

December 31

252

NOTE. — The above and several following statistical tables are taken
from the United States Geological Survey, Department of Mineral Resources.

134

TREATISE ON COKE

NUMBER OF COKE OVENS, BEEHIVE AND BY-PRODUCT, IN THE

UNITED STATES ON DECEMBER 31 OF EACH YEAR FROM

1880 TO 1902, WITH THEIR ANNUAL OUTPUTS

Year

Number of
Ovens

Output
Net Tons

Year

Number of
Ovens

Output
Net Tons

1880

12,372

3,338,300

1892

42,002

12,010,829

1881

14,119

4,113,760

1893

44,201

9,477,580

1882

16,356

4,793,321

1894

44,772

9,203,632

1883

18,304

5,464,721

1895

45,565

13,333,714

1884

19,557

4,873,805

1896

46,944

11,788,773

1885

20,116

5,106,696

1897

47,668

13,288,984

1886

22,597

6,845,369

1898

48,383

16,047,209

1887

26,001

7,611,705

1899

49,603

19,668,569

1888

30,059

8,540,030

1900

58,484

20,533,348

1889*

34,165

10,258,022

1901

64,001

21,795,883

1890

37,158

11,508,021

1902

69,069

25,401,730

1891

40,057

10,352,688

The year 1880 marks the first great appreciation of the value
of coke for the manufacture of Bessemer pig iron. It marked an
era of rapid uplift in the values of coke and coking-coal lands. It is
well to note that the number of ovens at the close of each year
represents those in existence, but it does not mean that there were

RECORD OF BY-PRODUCT COKE MAKING FROM 1893 TO 1902

Ovens

Year

Production

x ear

Net Tons

Built

Building

1893

12,850

1894

16,500

1895

18,521

1896

160

120

83,038

1897

280

240

261,912

1898

520

500

294,445

1899

1,020

906,534

1900

1,085

1.096

1,075,727

1901

1,165

1,533

1,179,900

1902

*1,663

tl,346

1:1,403,588

* Includes 525 Semet-Solvay, 1,067 Otto-Hoffman, 15 Schniewind, and
56 Newton Chamber's ovens; flncludes 210 Semet-Solvay, 664 Otto-Hoff-
man, 412 Schniewind, and 60 Retort Coke Company ovens; JBy-product
coke embraced in general table of coke production in the United States.

that many in active operation. In this connection it is interesting
to note the increase in the productive capacity of the coke ovens
in the United States. It is not possible to compare the number
of ovens in actual operation each year, and the averages must be

TREATISE ON COKE

135

based on the number of ovens in existence at the close of each
year. In 1880, the number of ovens in existence was 12,372 and
the total coke production was 3,338,300 net tons, an average of
278 tons of coke per oven. In 1890, the total number of ovens
reported was 37,158 and the production of coke was 11,508,021 net
tons, an average of 310 tons of coke per oven. In 1900, the total
number of ovens reported was 58,484 and the production was
20,533,348 net tons, an average of 351 tons of coke per oven. The
number of ovens in use in 1900 was 4.7 times those in existence in
1880. The output of coke in 1900 was 6.2 times. that of 1880.
The increase of production in 1901, as compared with the preceding
year, was 1,262,535 net tons, or 6.15 per cent. Coke production
in 1902 overtopped all previous records; it was 25,401,730 net tons,
exhibiting an increase over 1901 of 3,605,847 net tons or 16.5 per

RECORD OF BY-PRODUCT COKE OVENS BY STATES, AT THE
CLOSE OF 1900, 1901, AND 1902

States

Ovens,
December 31, 1900

Ovens,
December 31, 1901

Ovens,
December 31, 1902

Completed

Building

Completed

Building

Completed

Building

Alabama

120
400

355

60
120

120

30
100
564
50
232

120

400
30

• 30
. 50
355
60
120

120

200

45
100
564

504

240

400
75
100
30
50
592
56
120

40
200

574
60
412

Maryland

Massachusetts. . . .
Michigan
New Jersey
New York .

Ohio . .

Pennsylvania. . . .
Virginia
West Virginia. . . .

Totals

1,085

1,096

1,165

1,533

1,663

1,346

cent. The inability of railroads to furnish cars and motive power
materially reduced this year's output, increasing the expense of
production.

The records of the number of by-product coke ovens in the
above table are accumulative; the whole number of these ovens
completed and building in the United States at the close of the
year 1902 is given in the last two columns, 1,663 built and 1,346
building.

By the term yield is meant the percentage of merchantable coke
that has been 'obtained from the coal used in its manufacture.
The table shows that the genera,! average for most of the years
given is about 64 per cent., but in most instances this indicates
the value of the coke oven used and the care afforded the coking
operations. Until recent years, these elements in securing full

136

TREATISE ON COKE

CO CO ^

Tt< Oi CO

Oi O CO CO Oi O
t> 00 CO Oi O5 T— i
00 b- •* <N O Oi

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1>£

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t>« CO CO O CO T-I iO 1>

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o^ o

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coos oootoonoc;

tOCO OQCO(M^ T-I
COCO O5 CO

e -s

TREATISE ON COKE

137

APPROXIMATE STATEMENT OF AMOUNT OF COAL REQUIRED TO

PRODUCE 1 TON OF COKE IN EACH YEAR SINCE 1880,

WITH PERCENTAGE OF YIELD (NET TONS)*

Year

Tons

Pounds

Per Cent.
Yield

Year

Tons

Pounds

Per Cent.
Yield

1880

1.57

3,140

63.0

1892

1.57

3,140

64.0

1881

1.59

3,180

63.0

1893

1.57

3,140

63.5

1882

1.58

3,160

63.0

1894

1.56

3,120

64.0

1883

1.56

3,120

64.0

1895

1.56

3,120

64 0

1884

1.63

3,260

61.0

1896

1.58*

3,170

63.0

1885

1.58

3,160

63.0

1897

1.57

3,140

63.5

1886

1 56

3,120

64.0

1898

1.57

3,140

63.6

1887

1.56

•3,120

64.2

1899

1.54

3,080

65.1

1888

1.51

3,020

66.0

1900

1.57

3,140

63.9

1889

1.55

3,100

64 0

1901

1.57

3,140

63.9

1890

1.56

3,120

64.0

1902

1.56

3,129

64.1

1891

1.58

3,100

63.0

*These figures include both beehive and by-product coke.

PERCENTAGE OF YIELD OF COKE FROM THE SEVERAL QUALITIES
OF COALS USED IN ITS MANUFACTURE IN EACH STATE
AND TERRITORY DURING 1896-1902

State or Territory

1896

1897

1898

1899

1900

1901

1902

Alabama,

57 5

58 8

59 0

58 9

55 8

60 2

Colorado a
Georgia

56.9
49 0

55.6
49 3

59.1
61 0

59.0
65 2

62.0
52 4

58.4
60 7

59.2
63 3

Illinois

66 7

43 0

35 0\

Indiana

49.0

41 4

44. 9J

56.2

57.1

Indian Territory . .
Kansas

40.0
53.5

44.3
52 5

46.5
53 0

41.0
53 6

48.0

57.7

50.0
61.4

44.6
58.3

Kentucky . .

48.6

50.0

50 0

53 5

50.2

49.0

47.8

Massachusetts .....
Missouri

55.9

56.0

49 3

53.8

55.3

52.5

55.4

Montana.
New Mexico
New York
Ohio
Pennsylvania 6. . . .
Tennessee .........
Texas

53.0
61.7

62.7
66.1
56.5

48.5
55.6

62.7
66.2
55.0
56.3

56.0
55.6

63.5
65.7
54.6

51.0
64.3

58.8
68.1
55.8

50.3
60.3

62.5
66.2
55.6

55.4
57.5

66.9
66.0
54.6

53.7
56.9

66.6
65.9
54.6

Utah
Virginia

58.9

61.6

62.0

62.2

63.2

64.7

65.5

Washington
West Virginia
^Visconsin

67.0
61.4
62 0

67.0
61.0
59 0

62.2
61.2
59.0

59.8
60.0
60.8

61.5
60.9
60.01

62.7
61.1

58.8
61.7

Wyoming

47.6

43.7

51.9

48.7

44. 7J

71. lc

70. 2C

Total average . . .

63.

63.5

63.6

65.1

63.9

63.7

64.1

0 Average, including Utah.

6 Average, including New York, also Massachusetts for 1899.
c Includes Illinois, Indiana, Massachusetts, Michigan, New York,
Wisconsin, and Wyoming.

13cS

TREATISE ON COKE

yields from the several qualities of the coals have not received the
consideration that their importance demanded.

Two elements must be harmonized to secure the largest per-
centage of merchantable coke in the different types of coke ovens:
(1) properly applied skill; (2) correct knowledge of the quality of
the coking coal. It may be added that in all dry coals inheriting
a large percentage of fixed carbon, with a correspondingly low
volume of hydrogenous matter, some of this fixed carbon must be
consumed in the coking process; while, on the other hand, coking
coal with a large volume of volatile combustible matter will require
very little of its fixed carbon in the process of coking.

The table on page 137 indicates a slight general average increase
of percentage of coke product during 1902 over that of 1901, but
there is evidently room for further increased percentage of coke.

DIAGRAM ILLUSTRATING THE GROWTH OF THE MANUFACTURE

OF COKE IN THE UNITED STATES FROM 1880 TO

1902, INCLUSIVE

Years

TREATISE ON COKE

139

AMOUNT OF COKE PRODUCED IN THE UNITED STATES FROM

1880 TO 1902

Year

Net Tons

Year

Net Tons

Year

Net Tons

1880

3,338,300

1888

8,540,030

1896

11,788,773

1881

4,113,760

1889

10,258,022

1897

13,288,984

1882

4,793,321

1890

11,508,021

1898

16,047,209

1883

5,464,721

1891

10,352,688

1899

19,668,569

1884

4,873,805

1892

12,010,829

1900

20,533,348

1885

5,106,696

1893

9,477,580

1901

21,795,883

1886

6,845,369

1894

9,203,632

1902

25,401,730

1887

7,611,705

1895

13,333,714

COKE IMPORTED AND ENTERED FOR CONSUMPTION IN THE UNITED
STATES FROM 1869 TO 1902 (NET TONS)

Year
Ending
June 30

Quantity

Value

Year
Ending
Dec. 31

Quantity

Value

1869

$ 2,053

1886

28,124

$ 84,801

1870

6,388

1887

35,320

100,312

1871

19,528

1888

• 35,210

107,914

1872

9,575

9,217

1889

28,608

88,088

1873

1,091

1,366

1890

20,808

101,767

1874

634

4,588

1891

50,753

223,184

1875

1,046

9,648

1892

27,420

86,350

1876

2,065

8,657

1893

37,183

99,683

1877

4,068

16,686

1894

32,566

70,359

1878

6,616

24,186

1895

29,622

71,366

1879

6,035

24,748

1896

43,372

114,712

1880

5,047

18,406

1897

34,937

98,077

1881

15,210

64,987

1898

46,127

142,334

1882

14,924

53,244

1899

31,197

142,504

1883

20,634

113,114

1900

115,556

371,341

1884

14,483

36,278

1901

72,727

266,075

1885

20,876

64,814

1902

140,488

423,775

From the above it will be seen that this imported coke cost
per ton as follows: 1872, $.962; 1880, $3.645; 1890, $4.8975;
1900, $3.215; 1902, $3.165.

COKE EXPORTED FROM THE UNITED STATES SINCE 1895
(NET TONS)

Year

Quantity

Value

Year

Quantity

Value

1895

. 1896
1897
1898

131,368
169,189
173,034
199,562

$425,174
553,600
546,066
600,931

1899

1900
1901
1902

280,196
422,239
430.450
439,590

$ 858,856
1,358,968
1,561,898
1,785,188

The amount and value of coke exported from the United States
have increased each year since 1895, as seen in the above table.

The prices obtained for this coke per ton, are as follows: 1895,
$3.2375; 1898, $3.01; 1900, $3.2175; 1902, $4.06.

140

TREATISE ON COKE

**
^

rH 00 <N
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lOOrH
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t^o o o o

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t> rH OS

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30,219,343

00 00 00
<M OS t^.

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tO (M tO

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°°°°

t- ^

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TH CO !>•

co"
1— 1

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to ^ Tt< »oco

00 rH

co"

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OS (M OS I> CO
iO O Tfi t>(M

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CO OS to

iocoosi>

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rH

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State or Territory

::•:::

. • oS • •

•a .a

^ 1

> >^

£ ^

Si 8

c a

TREATISE ON COKE

141

CONDITION OF COAL CHARGED INTO COKE OVENS, WHETHER RUN-

OF-MINE, SLACK OR SCREENED, WASHED OR UNWASHED,

DURING THE YEAR 1902

State or Territory

Run-of-Mine

Slack or Screened

Total

Unwashed

Washed

Unwashed

Washed

Alabama

1,233,117
831
28,600

5,000

161,783
21,615,568
287,064

1,018,148

1,262,393
6735,194

509,376

3,947
1,766
28,159

99,628

602,287
334,109

68,546

290
641,422

14,126
91,496

10,430
208

19,618
1,623,624
47,161

697,962

2,517,223
117,528

2,494,708
1,052,935
101,042

106,987
19,935
140,466

40,735

38,000
1,175,847
357,530

298,963
255

4,237,491
1,695,188
129,642

110,934
35,827
265,121

10,430
99,628
40,943

219,401
25,017,326
1,025,864

1,716,110
68,546
4,078,579

852,977

Colorado"
Georgia
Illinois6

Indiana6

Indian Territory.
Kansas . . .

Kentucky

Massachusetts6 . .
Missouri
Montana

New Mexico . . .
New York
Ohio

Pennsylvania. . . .
Tennessee

Utah.

Virginia
Washington

West Virginia . . .
Wisconsin 1
Wyoming /

Totals . .

26,347,698

1,647,818

5,781,088

5,827,403

39,604,007

."Includes Utah.
6 Includes Illinois, Indiana, and Massachusetts.

The above table shows that, as a general average with all
kinds of coal, it required 1.5591 tons of coal to make 1 ton of coke.

CONDITION OF COAL USED IN THE MANUFACTURE OF COKE
THE UNITED STATES, FROM THE YEAR 1890 TO 1902,
INCLUSIVE (NET TONS)

Year

Run-of-Mine

Slack or Screened

Total

Unwashed

Washed

Unwashed

Washed

1890

14,060,907

338,563

2,674,492

931,247

18,005,209

1891

12,255,415

290,807

2,945,359

852,959

16,344,540

1892

14,453,638

324,050

3,256,493

779,156

18,813,337

1893

10,306,082

350,112

3,049,075

1,211,877

14,917,146

1894

9,648,750

405,266

3,102,652

1,192,082

14,348,750

1895

15,609,875

237,468

3,052,246

1,948,734

20,848,323

1896

11,307,905

763,244

4,685,832

1,937,441

18,694,422

1897

13,234,985

1,037,830

4,180,575

2,453,929

20,907,319

1898

16,758,244

1,672,972

4,487,949

2,330,405

25,249,570

1899

20,870,915

1,457,961

4,796,737

2,913,730

30,219,343

1900

21,062,090

1,369,698

5,677,006

4,004,749

32,113,543

1901

23,751,468

1,600,714

4,546,201

4,309,582

34,207,965

1902

26,347,698

1,647,818

5,781,088

5,287,403

39,604,007

142

TREATISE ON COKE

In the preceding table, the columns of washed coal indicate in
a marked manner that coke makers have entered into an era of
washed coal in the manufacture of coke. This gradual increase
in coal washing also indicates the reduction of the areas of coking-
coal lands whose coal required no washing for use in coke ovens.

AVERAGE VALUE PER NET TON OF COKE, AT THE OVENS, MADE

IN THE UNITED STATES, FROM 1897 TO 1902,

BY STATES AND TERRITORIES

State or Territory

1897

1898

1899

1900

1901

1902

Alabama

$2.140
2.916
1.280
3.450
1.500
1.410
1.500
6.890
2.250
2.480
1 . 5306
1.810

1.400
4.420
1.310
1.870
1.995

4.300
3.000

$2.030
2.590
1.560
2.833
1.544
1.448
1.420
6.906
2.095
2.470
1 . 5006
1.630

1.317
4.270
1.260
2.020\
1.750J

3.500
3 . 500

$2.03
2.51
2.30
2.96
2.13
1.99
1.93
6.32
2.25
3.04
1.696
1.95

1.73
4 98
1.53

2.35

d •

3.75

2.46

$2.667
2.820
2.849
3.990
2.520
2 . 465
2 520
6.159
2.909
2.690
2.220
2.670

2.137
4.797
2.010

2.870

$2.820
2.420
2.830
4.140
2.110
2.070
2.099
5.918
2.840
2.750
1.885
2.358

1 . 635

4.858
1.800

2.849

$3.250
2.740
3.643
4.100
2.617
2.505
2.500
6.750
3.178
3.370
2.330
2.850

2.065
4.940
2.318

3.446

Colorado"
Georgia

Indian Territory .
Kansas ....

Kentucky

Missouri

Montana

New Mexico
Ohio

Pennsylvania ....
Tennessee
Utah0

Virginia

Washington

West Virginia ....
Illinois

Indiana

Massachusetts . . .
Michigan

New York
Wisconsin
Wyoming

Average

$1.663

$1.594

$1.76

$2.310

$2.039

$2.490

c Included with Colorado.

d Included with Pennsylvania.

a Includes Utah.

6 Average value, including New York,
and also Massachusetts in 1899.

NOTE. — The great majority of prices secured for coke at ovens in the
above table shows that, excepting the brief boom times, very little if any
margin of profit has been secured; in fact, during some of these years coal
was receiving prices equal to, if not above, that of coke. — ED.

TOTAL VALUE OF COKE, AT THE OVENS, MADE IN THE UNITED
STATES, FROM 1880 TO 1902

Year

Value

Year

Value

Year

Value

1880

$ 6,631,265

1888

$12,445,963

1896

$21,660,729

1881

7,725,175

1889

16,630,301

1897 .

22,102,514

1882

8,462,167

1890

23.215.302

1898

25,586,699

1883

8,121,607

1891

20,393,216

1899

34,670,417

1884

7,242,878

1892

23,536,141

1900

47,443,331

1885

7,629,118

1893

16,523,714

1901

44,445,923

1886

11,153,366

1894

12.328,856

1902

63,339,167

1887

15,321,116

1895

19,234,319

TREATISE ON COKE

143

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144 TREATISE ON COKE

In the preceding tables a steady increase both in the number
of plants and ovens, as well as in total output, will be noticed.
It is of interest also to notice the increased capacity of the individual
ovens. In 1880, 12,372 ovens produced a total output of 3,338,300
short tons of coke, an average of 270 short tons per oven. During
the year 1902, there were in active operation 67,124 ovens, which
produced 25,401,730 short tons of coke, an average of 378.4 tons
per oven. In 1901, the total number of active ovens was 61,396
which produced 21,795,883 tons of coke, an average of 355 tons
per oven, showing that the average productive capacity of each
oven in 1902 exceeded that of the preceding year by 23.4 tons.

CHAPTER V

MANUFACTURE OF COKE

Methods of Coking Coal. — Coking is the art of preparing from
bituminous or other coal a fuel adapted for metallurgical and
other special uses. The operation consists in expelling by heat
the gaseous elements from coking coals, leaving the fixed and
deposited carbon, ash, and the residue of
sulphur and phosphorus. These consti-
tute what is known as coke. There are
three principal methods now in general use
in the manufacture of coke: (1) Coking
the coal in heaps or mounds, in the open
air; (2) coking the coal in the beehive or
round oven partly enclosed, with the air
partially excluded; (3) coking in retort or
closed ovens, with air almost entirely
excluded. In these methods there are
some modifications, but the governing
principles are maintained in whole or part.
The open-pit method is rapidly disap-
pearing, as it is wasteful of the coal and
tedious in operation. The beehive coke
oven holds its place firmly from its
moderate cost in construction and sim-
plicity in operation, with its product of
the best possible metallurgical fuel. The
retort coke oven, with its supplemental
apparatus for saving of by-products,
affords many advantages in special localities and under favorable
conditions, but from its large cost in construction and installation,
with the expert agencies required in its operations, it cannot hope
for general application.

Coking Coal in Heaps or Mounds. — The open-air coking in
heaps or mounds has been copied from the mounds of the charcoal
burners. This primitive and wasteful mode of coking requires a
yard made by leveling the ground and surfacing it with coal dust.
The coal to be coked is then arranged in rectangular heaps or

145

(b)
BENNINGTON COKE PITS

146 TREATISE ON COKE

mounds, Fig. 1, with longitudinal transverse, and vertical flues;
sufficient wood having been distributed in these to ignite the mass
of coal.

Beginning on the prepared floor, a base of coal a 14 feet broad
is spread to a height of 18 inches. On this base the flues are
arranged and constructed as shown in the plan (a), the flues being
built of refuse coke and lump coal and covered with suitable
billets of wood. The coal is piled up as shown in the cross-
section (6). When the mound is ready for coking, fire is applied
at the base of the vertical flues c, c, igniting the kindling wood at
each alternate flue. As the process advances, the fire is extended
in every direction, until the whole mass is ignited.

Considerable attention is required in this method of coking in
constructing the mounds, in diffusing the fire evenly through the
mass, in preventing waste by admitting the proper volume of air,
and in banking up the mounds with fine dust as the coking opera-
tion is completed from base to top.

When the gaseous matters have been expelled, which is seen
when flames cease to appear, the whole heap is closed up with fine
dust and partially smothered out. The final operation consists
in the application of small quantities of water delivered by a hose
down the flues, which is quickly converted into steam permeating
the whole mass of coke. This gives coke with freedom to develop
cells and, under careful management, with a small percentage of
moisture. The time required for coking a mound of the dimen-
sions given, without limiting its length, is from 5 to 8 days, depend-
ing on the state of the weather.

The yield of coke, at the Bennington yard, is as follows:

GROSS TONS

Coal used in mound 56 . 87

Coke drawn from mound . 33 . 63

Loss in coking 23 . 24

This primitive method of coking is very wasteful of the coal
and slow in operation.

Some efforts at progress, in methods of coking to secure
greater economy in the coal, have been made in the early period
of evolution, by a plan for coking in open-top, rectangular masonry
enclosures. These were made with side walls, 5 to 8 feet in height,
having air ports along their longer sides.

The method of coking in these rectangular kilns was very
similar to those used in the mound coking, but has little to com-
mend it in the economy of its work. All that can be urged in
its favor is that it was a step in the progress of improvement
toward the modern coke ovens.

The beehive coke oven followed. The following analyses will
exhibit the result of its work with the Connellsville coal:

TREATISE ON COKE

147

ANALYSES OF CONNELLSVILLE COAL AND COKE

Coal
Per Cent.

Coke
Per Cent.

Moisture

1 25

Volatile matter

31 80

Fixed, carbon

59.79

87.05

Ash

7.16

10.60

Sulphur

.53

.74

To Determine Loss of Carbon in Process of Coking. — To deter-
mine the waste in coking by this system, the fixed carbon, ash,
and sulphur go to make the coke. Allowing for the volatilization
of sulphur in coking, then 59.75 + 7.16 + .44 = 67.39. Then
100 *. 67.39 = 1.484 tons of coal to make 1 ton of coke.

The fixed carbon in the coke should therefore be, 1.484 X 59.79
= 88.728 per cent.; but it is only 87.05 per cent., exhibiting a
loss of fixed carbon in coking of 1.882 per cent.

Two additional elements enter into this result; the percentage
of fixed carbon deposited from the volatile hydrocarbon of the
coal, giving the coke the silvery glaze that distinguishes it so
prominently. The other element is the moisture in the coke;
the percentage of this depends on the care exercised in quenching
or cooling the incandescent coke in the beehive oven, ranging
from 1 to 3 per cent.

The actual loss of fixed carbon in coking would be the calcu-
lated loss plus the deposited carbon minus the moisture remain-
ing in the coke. Some of the volatile matter in the slates and
shales forming the ash will be volatilized in the process of coking,
but this is so small an element that practically it is disregarded.
The conditions of carbon deposit, with the percentage of moisture
in the coke, will hold in all the methods of coking. It is also evident
that the higher the percentages of fixed carbon and ash in any
coal, the greater the aggregate percentage of the product in coke.

A recent test of a sample of the Kanawha Valley coke, made
from the rich bituminous coal of that region, will -further illustrate
the method of determining the loss of fixed carbon and other
elements in the coal in the coking process.

ANALYSES OF KANAWHA VALLEY COAL AND COKE

Coal
Per Cent.

Coke
Per Cent.

Volatile matter . . .

34 . 7900

.000

Fixed carbon

57.8600

89.200

Ash

6.2000

9.500

Sulphur

1.1500

1.300

Phosphorus • •

.0157

.024

148

TREATISE ON COKE

From the foregoing analyses it is evident that, taking the
fixed carbon, ash, and 74 per cent, of sulphur, we have 57.96 + 6.20
+ .85 = 64.91. Hence, 100 H- 64.91 = 1.540 tons of coal to make
1 ton of coke.

The fixed carbon in the coke is therefore 57.86 X 1.540 =
89.10 per cent.; but by analysis it is 89.20 per cent., exhibiting a
slight gain of this element. This is secured from the large deposit
of carbon glaze from this very rich bituminous coal. The other
elements in the coke can be determined on the above general
principles.

BEEHIVE COKE OVEN

The name beehive evidently had its genesis in the close resem-
blance of the internal form of this oven to the ancient dome-shaped
beehive.

The initial form of the beehive coke oven is given in Fig. 2,
which shows the effort to introduce a partially enclosed oven early

in the manufacture of coke.
It is not very clear whether
this plan of oven was sug-
gested by the form of the
dome-shaped mound method
of coking coal or from the
charcoal kilns. It was built
with refractory materials and
in some instances had flues
in its heavy walls.

The product of this oven
could not differ much from
that of the modern beehive
oven of 1880, 1890, and 1902,
only the waste of carbon in
the former was much more
than in the improved oven.
The ancient beehive oven
was originally constructed
on a diminutive scale in the
"day of small things," but
it has continued to grow in
size through a century and
a half until it has attained
dimensions of 12 feet to 13 feet in diameter, with a height of dome
above the floor of 7 feet to 8 feet. The height of the door of this
oven has been increased so as to admit the air at a level somewhat
above the charge of coking coal to prevent the waste formerly

*From Mr. A. L. Steavenson, in Vol. VIII., North of England Mining
Engineers, 1860

FIG. 2.

Section plan

PLAN OP COKE OVENS NEAR NEWCASTLE-

UPON-TYNE*

17303— v

FIG. 3. WORKING PLAN FOR THE CONSI

? ^^3

tL r-***-V
«f / . \.«*»

T U— 2^'
d

•ION OF BEEHIVE OVENS, OLIVER PLANT

^i.n.1

TREATISE ON COKE

149

150 TREATISE ON COKE

sustained at this place by contact of the air with the coke in low-
door ovens, leaving a deposit of ashes along the line of this air draft.

A number of improvements have been made in the construction
of this oven, especially in the preparation of shaped firebrick for
doors, jambs, dome, and charging port. In addition to these
improvements, recent practice has secured the use of silica brick
for the dome, increasing greatly the wearing properties of the
oven, especially in this portion of it, which is subjected to the
most intense heat in the coking operations. Mr. O. W. Kennedy
introduced the use of silica brick and estimates that they will
wear three to four times as long as the fireclay brick.

In some ovens, an annular passage for the admission of air,
with perforations for its equal distribution above the level of the
charge of coal, has been tried with increased economy in saving
the burning of the carbon of the coal.

BEEHIVE OVEN OF 1894

Beehive Oven, 1894 Type. — Fig. 3 exhibits working plan with
details of the usual method of constructing this oven, dating about
the year 1894. A bank of a double row of this class of ovens was
constructed near Gallitzin on the Alleghany Mountain. The design
was to coke coals from the Upper Kittanning (B) and the Upper
Freeport (E) seams. As these coals are only medium in fusing
matter, the moderate size of this oven answered the purpose very
successfully.

Beehive Oven at Oliver Plant. — A plan and section given in
Fig. 4 illustrate the larger beehive coke ovens more recently con-
structed at the Oliver plant, near Uniontown, in the Connellsville
region. These have been kindly furnished by Messrs. Wilkins and
Davison, engineers, Pittsburg, Pennsylvania, who are experts in
this and kindred constructions.

The interlocking plan shown in the bank of coke ovens, Fig. 4,
is sometimes used to compact more closely the group of ovens; at
other localities, it is adopted to economize space where the ground
for the ovens is limited.

Continental Coke Oven. — Fig. 5 exhibits plans and sections
with detailed drawings of the coke ovens of the Continental Coke
Company's works, No. 1, near Uniontown, Fayette County, Penn-
sylvania. These ovens are in the Connellsville coke region and are
of the modern enlarged plan of the beehive coke oven.

The section in Fig. 6 shows an arrangement for an extended
works where ample ground can be secured. These two figures
show plans and sections of the coke ovens, wharves, and railroad
sidings, with dimensions given in full details. These several
banks of ovens with their respective coke wharves have been built

NMl

— ^

FIG. 5. BEEHIVE Ov

17303— v

FIG. 6. ARRANGEMENT OF OVENS A

CONTINENTAL COKE Co.

rCRKS OF THE CONTINENTAL COKE Co.

Tile.

Yard Level

151

Dry Masonry ,
FIG. 7 (a)

152

TREATISE ON COKE

FRONT ELEVA TION
FIG. 7 (fe)

up from the low ground
and involve considerable
masonry work as well as
much embanking. While
this method of construc-
tion is expensive in first
cost, since the ovens are
raised high above the
ground, they are free from
dampness and assure the
best results in their coke
product.

Wharton Coke Oven.

Fig. 7 exhibits a modern
plan of the beehive coke
oven as it has been con-
structed in a plant of 300
ovens at the Joseph
Wharton Coke Works at
Coral, Indiana County,
Pennsylvania.

The general design is
given in the drawing with
some details. The oven
is 12 feet by 7£ feet. It
was planned mainly for
coking coal from the
upper Freeport bed (E).
This coal, as well as all
others in Indiana County,
requires a preparation for
use in manufacturing mer-
chantable coke for metal-
lurgical uses. The fusing
matter is not as high in
this coal as in the
Connellsville. At these
works, to avoid the pro-
duction of black ends, so
undesirable in blast-fur-
nace work, a subfloor of
red brick has been laid
under the usual tile floor
of these ovens; this addi-
tional floor stores heat
and prevents the produc-
tion of black ends, the

TREATISE ON COKE

153

coke coming out of the oven with a silvery clearness to the floor
of oven. Another peculiarity of the construction of these ovens
is the second sustaining arch over and supplementary to the heavy
jamb brick arch over the door of the oven. This higher arch is
designed to sustain the front of the oven structure while repairs
are being made to the large shaped brick in the arch and jambs
of the ovens, without the labor and expense of tearing down a
large section of the oven. Silica brick were used exclusively in
the domes or crowns of these ovens. This will conduce greatly to
the length of their work and economy in their repairs.

The section shown in Fig. 8 illustrates the arrangements of the
ovens with the ample wharf room, the retaining wall, and railroad

FIG. 8

siding, with related elevations to secure the utmost facilities in the
manufacture and shipment of the coke.

It may be noted here that the operations of the modern beehive
coke oven secure two desirable properties in metallurgical coke, viz. :
its full cellular developments, assuring the maximum calorific
energy in its combustion, and its dry condition with minimum
percentage of moisture.

It may be conceded, however, that the cost of labor and waste
of carbon in coking in the beehive oven are somewhat in excess of
similar work in some of the modern retort coke ovens.

This plant of beehive coke ovens at the Wharton works is
very complete in all its parts and is a model in its design and
construction.

The general plan of this large plant of coke ovens was matured
by Mr. Harry McCreary, general superintendent, ably assisted by
Mr. R. M. Mullen, civil engineer. The estimated cost of one oven
of the Wharton type, in 1903, is given in table on page 154.

CONSTRUCTION OF THE MODERN BEEHIVE OVEN

Excavation for Foundations. — The excavation for all founda-
tions for masonry work should be cut to such depth beneath the
surface of the ground as will assure stability to the masonry and
exemption from its disturbance by frost. The depth and general

154

TREATISE ON COKE

foundation conditions must be studied in each locality, and should
be under the direction of a competent engineer, or such agent as
the management may appoint.

Masonry of Retaining Walls. — The masonry of the retaining
walls of the coke ovens should be laid dry with sound sandstones, of
even beds and of such thickness as hereafter described. This dry-
laid foundation should be carried to the level of the coke wharf in
front of the coke ovens. Above this foundation course the masonry
should be laid in lime mortar or cement, composed of two parts of
clean, sharp sand and one part of good slacked lime or cement,

ESTIMATED COST OF ONE WHARTON COKE OVEN

Price

Amount

1 254 lining brick

$18.00

$22 . 57

2 487 crown brick silica brick

18.00

44.76

113 tile 12 in X 12 in X 3 in

55.00

6.22

1 set arches and iambs .

8.00

770 paving brick in bottom of oven

8.00

6.16

660 mill brick in front of oven

8.00

5.28

2.00

1 cast-iron door frame

5 00

30 lineal feet, 70-pound cross-rail to carry larry rail — 1
700 pounds . ....". . . J

30.00

10.50

29 lineal feet, 70-pound larry rail, 655 pounds
14 lineal feet, cast-iron water pipe, 434 pounds
13 4 cubic yards mortar wall . . . .'

30.00
.02
2.75

9.80
8.68
36.85

1 . 5 cubic yards brickwork in front of oven
Building oven complete

4.90
29.25

7.35
29.25

125 cubic yards excavation for oven seat, yard, and!
railroad • /

.40

50.00

7 railroad ties

.35

2.45

28 lineal feet, 70-pound rail for railroad track — 6551
pounds J

30.00

9.83

20 cubic vards of dry wall per oven

2.35

47.00

Total cost of oven

$311 70

the whole carefully mixed to secure a thorough blending of these
materials. The building stones should be sufficiently large and
broad-bedded for this purpose to assure good bond and strong
work to resist the alternating pressures from the heat changes in
the coking operations. Flagstones with good beds, having an
average thickness of 6 inches to 8 inches, should be used in the
retaining wall above the level of the floor of the oven.

The outer face of the masonry should be neatly trimmed and
the bedding of the stones dressed to lie firmly on each other without
the aid of chips or pinners. The face of this wall should be carried,
up with a uniform batter of at least 2 inches to the' vertical foot.
Great care should be taken in embedding the stones in the mor-
tar and thoroughly filling all joints and interstices. Seats for the

TREATISE ON COKE 155

bases of the iron door frames of the oven should be carefully
dressed to an even surface to assure stability at this important
part of the ovens. The arch piece of this iron door frame is to
be omitted, as its expansion under heat has been found to be a
disturbing element to the jambs and supplementary arches.

Building the Coke Oven. — The foundation under the oven
should be cleared of all vegetable or combustible matter and the
foundation of the circular wall should -begin on firm materials —
whether on rammed embanking ground or in excavations under the
surface. The building of the oven should conform accurately to the
plan selected for the locality. It should be built of shaped firebrick
and silica brick composed of materials especially adapted for the
service demanded in their use in the oven — strong heats with water
contact in the quenching or cooling of the coke charge in the oven.

The circular section of the oven, from the foundation to the
springing of the arch of the dome or crown, should be built with
firebrick shaped to conform to the radial lines of this portion of
the oven. The physical composition of these firebrick should con-
sist of coarsely ground fireclay to provide • for the expansion by
heat and the shrinkage by water under these conditions in the
coking operations. The dome or crown of the oven should be
built with silica brick, holding not over 2 per cent, of lime in com-
bination. They should be shaped to conform to the radial planes
of this portion 'of the oven to secure compactness and stability,
and the whole should be keyed firmly by the charging port ring
in the crown of the oven.

The lines of the oven should be defined by sweeps from a
central pivoted stake. The oven door jambs, with shaped arch
brick connections, should be neatly and carefully laid. The supple-
mentary brick arch to maintain the front wall of the oven above
its door should be constructed on firmly set skew backs at the
springings of this arch. The mortar to be used in setting the fire-
brick work of the oven should be composed of loam, or loamed
clay, in such proportions as may be deemed most serviceable. A
mortar of ground fireclay and loam may be used in this work.

The tiles on the bottom of the oven should have a rise from the
door to the back of the oven of 6 inches. They should rest on a
thin stratum of sand on top of the subfloor of the oven. This
subfloor is to be built of red brick, laid on edge, in a sand bed on a
firmly compacted foundation. The use of this red-brick subfloor is
to store heat to prevent the production of "black ends " in the coke.

The filling under and around the oven should be made with
selected earth, and all vegetable or unsuitable matters removed.
The filling should be made in horizontal layers, not exceeding
1 foot in thickness It should be thoroughly wet and packed
solidly with rammers or rollers to prevent shrinking and settling.
To assure stability in this filling sufficient time should be allowed
it to settle and to partially dry.

156

TREATISE ON COKE

TREATISE ON COKE 157

The larry track should be made with T rails, weighing 70 to
80 pounds per lineal yard, to be laid on iron cross-ties or iron
girders with necessary chair fastenings. When a double row of
coke ovens is constructed, the larry track should be placed midway
between the charging ports of the ovens. In this case, the larry
should have discharging chutes on each side.

Cast-Iron Water Pipe. — A cast-iron water pipe 4 inches in
diameter, weighing at least 18^ pounds per lineal foot, should be
laid with its top surface 18 inches below wharf level, with taps
for coke-oven valve for each two coke ovens, with Powell's star
coke-oven valve on top.

Coke Wharf. — The level of the coke wharf should be 2 feet
6 inches below the sill of the iron door of the oven, with a moderate
inclination to the edge of the wharf wall. The width of the coke
wharf should be at least 40 feet. The level of heads of rails, on
the railroad siding, should be made of such grade under the level
of the wharf as to secure ample height for loading the coke into the
railroad cars, from 7 feet to 12 feet. The grade of the cove ovens
should be 1 foot to 100 feet (1 per cent.) where it is practicable,
and the railroad sidings of similar gradients. This will secure
descending gradients with the tonnage and secure easy handling
of railroad cars without the necessity of a locomotive.

Measurements. — All the stone masonry necessary to the com-
pletion of the coke ovens is measured in the wall with the dimen-
sions as given on the plan. All masonry is measured and paid
for by the cubic yard of 27 cubic feet. These measurements are
the actual cubical contents without any allowances.

The brickwork in the coke ovens is paid for by the oven.
This includes the laying of the jamb brick, facing brick, tiles,
silica brick, and all other work of this description in the complete
construction of the coke ovens. All excavation and filling are
paid for by the cubic yard.

The engineer or agent should issue directions from time to time
as the work progresses, and these should be carried out strictly
in accordance with his instructions. In all cases, the decision of
the engineer or agent, in the method of the construction of the
work and in the estimate of quantities, should be final and con-
clusive between the contracting parties.

Fig. 9 will be interesting as showing the process of the con-
struction of these beehive coke ovens.

THE COKING PROCESS

For the purpose of determining its exact percentage of coke
product, an exhaustive series of experiments was made at the
large coking plants of the Cambria Iron Company, in 12' X 6'
beehive ovens, in the Connellsville region under the care of Mr.
Isaac Taylor.

158 TREATISE ON COKE

The cross-sections of 48- and 72-hour charges of coal in these
ovens, Figs. 10 and 11, will show the process of coking from top
of charge to floor of oven, with the enlargement and shrinkage of
the resultant coke carefully and accurately defined from the
actual work of these ovens.

From the sections, Figs. 10 and 11, and the Tables I and II, it
will be readily seen that the average charge of coal for 48-hour
coke is 9,910 pounds, or 5 net tons nearly. It occupies a depth
in the coke oven of 23 inches. The charge of coal for 72-hour coke
is 11,915 pounds, or 6 net tons nearly. It has a depth in the oven
of 26| inches. These sections show, in a graphic way, the heights
of 48- and 72-hour coke in the ovens at "best," and its reduced
altitude after being cooled by watering in the oven. The process
of fusing and coking begins on the top surface of the charge of coal,
and goes down through the mass of coal at the rates shown in
the margins of the sections, until it reaches the bottoms of the ovens.

It will also be seen that in this process of coking hydrocarbon
gas will be evolved from the coal, which gas, passing up through
the fissures of the incandescent section of coked coal, deposits
some of its carbon. This gives the coke the bright silvery coating
that distinguishes the best cokes and partly protects them from
dissolution in the upper region of blast furnaces from the action
of the ascending gases.

The tables of careful tests, I and II, show in accurate detail
two series of determinations to learn the exact percentage of coke
produced, under careful management in the beehive coke oven.
They give the average results from an equal number of tests of
48- and 72-hour charges of coal in the product of coke.

Table I shows the usual and practical percentage of coke made
in these ovens in the usual way with the moisture from cooling in
the oven included. Table II shows the exact percentage of coke
as it has been drawn in a red-hot condition and exempt, or nearly
so, from moisture. This latter determination is impracticable, but
it was made to ascertain the ratio of carbon waste by the beehive-
oven method of coking.

In all these experimental tests, the coal charged into ovens and
the products in marketable coke, fine coke, or breeze, and ashes,
have been carefully separated and accurately weighed.

In the preparation of these tables, samplings of the coal used
and coke made were analyzed by the late Dr. James J. Fronheiser,
in the Cambria Iron Company's laboratory at Johnstown, Pennsyl-
vania, with the following results:

CONNELLSVILLE CONNELLSVILLE
COAL COKE

Moisture at 212° F 1 . 25 .63

Volatile matter 31 . 27 1 . 37

Fixed carbon 59. 79 85. 99

Ash 7.16 11.12

Sulphur 53 .89

tii^fYl I I II i 1f.:V::i

160

TREATISE ON COKE

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From the analysis of
Connellsville coal given
on page 158, used in these
coking tests, as shown in
Tables I and II, it will
be seen that the loss in
the coking operation, in
the wet and dry ways, is
30.71 and 36.24 per cent.,
respectively. This loss
arises from the expulsion
of moisture, volatile mat-
ter, and some of the fixed
carbon. The loss of the
fixed carbon is the most
important element in the
consideration of the work
of the beehive and all
other coke ovens. The
fixed carbon, ash, and
sulphur constitute the
coke. The sum of these
in this instance amounts
to 67.48. Dividing 100
by this number gives
1.481, the number of tons
of coal to make 1 ton of
coke. Then the fixed car-
bon in the coal, 59.79,
multiplied by 1.481, gives
88.549, the theoretic vol-
ume of carbon in the coke.
Hence, 88.549 : 100 =
85.99 : 97.11, or 2.89 per
cent, of loss of fixed car-
bon. Practically, it is
more than this, depend-
ing on the care in coking
and cooling the coke in
the oven.

In Table II, the coke
was drawn from the oven
hot and weighed in this
condition, showing that
the loss of carbon was
substantially the same as
in the former case, but
the loss in moisture and

TREATISE ON COKE 163

volatile matter was 36.24, exhibiting a reduction in moisture of
5.26 per cent.

A similar test on a bank of beehive ovens at Gallitzin, on the
Alleghany Mountains, running on coal from the Upper Freeport
seam, required 1.383 tons of coal to make 1 ton of coke. The
loss in fixed carbon was 4.42 per cent. Another test, under
similar conditions, at a coking plant in Elk County, Pennsylvania,
using coal from the Upper Kittanning seam, required 1.459 tons of
coal to make 1 ton of coke. The loss in fixed carbon was 2.71
per cent.

Practically, Table I shows that Connellsville coal, coked in the
modern beehive oven, will produce under careful and intelligent
management 66.17 per cent, of marketable coke, 2.30 per cent, of
small coke or breeze, and .82 per cent, of ashes. This enlarged
product of coke, 66.17 per cent., has been obtained by improved
methods in coking, by reducing the waste of fixed carbon at doors
of ovens, and by increasing their height so as to admit air above the
charge of coal in the oven, thus avoiding the old-time wastage at
this place. There is also a deposit of carbon from the expelled
volatile hydrocarbons of the coal in coking in their upward passage
through the incandescent coke, especially noticeable in the upper
section of coke.

Just how much carbon is deposited under the varying conditions
in coking 48- and 72-hour coke has not yet been accurately deter-
mined. After some experiments, in a crucible, in coking Connells-
ville coal, it was found that, under conditions similar to those of
the beehive oven, and admitting a proportional volume of air, the
resultant dry coke was 67.56 per cent., which is slightly in excess
of the theoretical or calculated yield of coke from this coal, 67.27
per cent. A second experiment consisted in the exclusion of air,
using the true retort method in coking. This gave 79.20 per cent,
of coke. We have, therefore, the two results: (1) by admitting
air, 67.56 per cent.; (2) by excluding air, 79.20 per cent.; exhibit-
ing an increase by the latter method of 11.64 per cent.

As the first coking test gives the full theoretic result of coke,
it is evident that there was no burning or waste of fixed carbon,
or if any was wasted an equal amount of deposited carbon
must have replaced it. In the second test, there was evidently
a large deposit of carbon from the gases of the coal, at least
14.71 per cent., assuming that no fixed carbon has been burned
in this retort test.

Practically, no construction of coke oven could afford the pre-
cision of admitting air and absolutely excluding it, as in these
laboratory tests. They show, however, that the retort -oven
methods of coking afford a larger yield of coke than can be obtained
by the beehive- or air-oven methods of coking. The relative
calorific values of the coke made in these two principal methods
will be taken up in a subsequent chapter.

164 TREATISE ON COKE

Old Welsh Oven. — In the progress of the manufacture of coke,
the elements of cost appear to have invited attention to the labo-
rious and expensive methods of drawing coke from the old and
cramped beehive ovens. The main effort in reducing cost was
directed to a new plan of coke oven, retaining the principles of the
beehive, but planning the new oven so as to draw the coke by
mechanical appliances.

The Welsh oven consists of an arched chamber 12 feet long,

7 feet broad, and about 6 feet high. One end of this oven is walled
up, the other end or front has doors or luted walls. A flue chimney
at the closed end of the oven affords egress to the gases.

The coke is drawn out by a drag composed of a main iron bar
running the length of the oven and having a crosspiece at the
inner end. The whole drag is placed in the bottom of the oven
before the charge of coal is placed in it, and it remains under the
charge of coal until it is coked and ready for drawing out, when a
chain is attached to an eye in the drag at front of oven, and the
coke pulled out in mass, by windlass or engine power. The coke
is usually quenched or cooled outside the oven.

With skill, this method of coke manufacture possesses some
advantages in the economy of the work in drawing the coke out
of oven, without injuriously affecting the physical condition of the
coke. The cooling outside the oven by watering is the chief objec-
tionable feature in this section of the work of coking, as coke
watered in this way, if done in a clumsy manner, will contain from

8 to 15 per cent, of water, which neutralizes the advantage secured
in the rapid drawing of the coke by mechanical means. This effort
at the improvement in the coke oven to save labor has been fol-
lowed by other plans on the same general principles, but mainly
designed at improvement in the details of these methods of the
several operations in coking.

The Thomas oven is simply an improved Welsh oven, preserving
the desirable properties of the beehive oven in coking the coal.
It secures some economy over the latter by its mechanical method
of drawing the coke. It retains, however, the undesirable method
of cooling the coke by watering it outside the oven.

This oven has been fully described in a paper prepared by
Mr. J. T. Hill, manager of the Coalburg mine, and read at the
meeting of the Alabama Industrial and Scientific Society, in 1891.
Fig. 12 illustrates its main features.

The descriptive text is as follows: "The essential difference
between the old Welsh oven and the Thomas oven exists in the fact
that the latter is much longer, affording greater capacity, and that
both ends are movable, thus doing away with the necessity of
placing the drag in the oven prior to charging. In nearly every
other respect the ovens are identical.

"At Coalburg there are sixty-four Thomas ovens arranged in
one single continuous battery. In construction, the same principles

TREATISE ON COKE

165

are carried out and materials used as in the beehive ovens, except
that the bottoms are of hard red brick, upon the theory that they
resist wear of the drag better than the firebrick. In detail they
are described as follows: length, 36 feet; width inside, 7 feet
3 inches at back, and 7 feet 9 inches at front; height over all, 8
feet; height of door, 4 feet; height inside, 5 feet to crown of arch.

(c)

Cross Sect/on one-f?a# way

(d)
FIG. 12. THOMAS OVEN

"Fall in bottom from back door to front, 1 inch in 3 feet, or
1 foot in the whole length of oven. Both back and front are mova-
ble and have swinging doors, which are in two sections, and built
of firebrick of special design, laid in iron frames.

"There are three openings on top, two funnel heads and one
draft stack near the back end of the oven. In front of it and on
a level with the floor of the ovens is an apron of stone and brick
masonry, 8 feet wide and running the entire length of the battery.

166

TREATISE ON COKE

Four feet below this masonry or apron is another piece of masonry
7 feet wide, which also runs the entire length of the battery, on
which the truck of the dinky containing the machinery for drawing
the coke is located. Still farther below is the railroad track, on
which are placed the cars for the receipt and shipment of the coke.
At the rear of the battery is another track, on which runs a car used
for conveying the drag from oven to oven, and on this car is per-
manently fixed a crab for pulling the drag back after discharging,
Fig. 13.

"Twelve tons of coal are charged from 6-ton larries, through
the funnel heads, and the leveling is done from both ends.

"When ready to draw, the doors at both ends of the ovens are
swung open and an iron rod passed through the oven over the top
of the hot coke, and attached to the drag at the rear. The hot coke

Mac/)//?ery /or drawn? Coke

FIG. 13. COKE DRAWER

is thus drawn in a body out of the front end of the oven, and over
a screen attached to the dinky, at which point the fire is quenched
with water falling from a tank, situated above the screen, no water
whatever being thrown into the oven. From the screen it falls in
broken pieces to the railroad car below and is ready for shipment."
The yield is practically the same as from the beehive ovens
under skilful management, and the Duality of the product, so far
as can be determined by analyses and observation, is fully up to
the standard. I regret that I cannot present data showing its rela-
tion to the beehive coke in furnace practice, but the conditions of con-
sumption are such that it has not been practicable to make such a
test. The claim for economy in reducing the labor in making coke in
this oven requires more data to define the exact amount. The rela-
tive original costs of this and the beehive oven, to produce a given out-
put per month, with the cost of repairs of each kind of oven, should
have been submitted in order to have a fair comparison of merits.

TREATISE ON COKE 167

It will readily appear that in all these ovens, with admission of
air through doors, or by special ports, the true principle of coking
is retained — freedom of the coal, by the shallow charges, to develop
the best physical structure in coking, as the pressure of these coal
charges in these broad horizontal ovens is so slight as not to mate-
rially compress the fusing mass in forming the cells in making coke.
On the other side, there is some waste by the admission of air in
burning the expelled gases in the crowns of the ovens above, -and
in contact with the coking coal.

This is all that can be urged against the use of these types of
coke ovens in the manufacture of coke. With care in cooling the
coke, especially when watered in the oven, a product is obtained
in best condition for affording the utmost calorific energy in metal-
lurgical operations.

Browney Coke Plant. — Desiring to learn the condition of the
beehive coke oven, in the celebrated Durham coke district in
England, and to be advised as to the progress of the introduction of
the narrow or retort coke oven there, with the status of efforts in the
saving of the by-products of tar and sulphate of ammonia, I wrote
Sir Isaac Lowthian Bell, the eminent authority on all matters con-
nected with the iron and steel industries, who kindly sent the draw-
ings, shown in Fig. 14, of the Browney colliery coke plant of Messrs.
Bell Brothers,* with the following note covering my inquiries:

ROUNTON GRANGE, Northallerton, May 22, 1893.
MY DEAR MR. FULTON:

Various circumstances, my own engagements not being the least, have
conspired to delay my reply to your letter of 10th ult.

I enclose the tracing of our own ovens, by means of the waste heat of
which we supply our collieries with steam power. In these, by-products
are wasted, as you no doubt will see. It is difficult, I may say impossible,
to give a categorical reply to your inquiry in respect to the narrow ovens
in which combustion in the ovenself is avoided and where, in consequence,
ammonia and tar escape decomposition. In certain districts, even in England,
they are successful, the difficulty being their maintenance in good repair.

In South Wales they seem to do very well; with us, in the county of
Durham, and in Yorkshire, the reverse has frequently been the result.
My own opinion is that the richness in combustion gas lies at the root of
the evil, the consequence being an elevation of temperature in the outside
flues which is incompatible with stability.

My own firm has spent large sums in pursuit of a plan of obtaining
ammonia, etc., and the firm of Messrs. Pease and Company is continuing
the process with perfect success as regards the by-products; but they, or
their customers, find, as we found, the coke not so suitable for blast-furnace
work as that burnt in the old-fashioned beehive oven.

I am very sorry that I find it impossible to see your exhibition at
Chicago. I must therefore be content to hear what others have to say on
the subject.

With my kindest regards to all my good and faithful friends in Johns-
town, believe me yours faithfully, I. LOWTHIAN BELL.

*The chimney for these ovens, the base of which is shown in the end
elevation, Fig. 14, extends 80 feet above the top of the ovens, and is battered
1 in 27.

168

TREATISE ON COKE

CE3

TREATISE ON COKE 169

I enclose a letter also from our engineer, Mr. Steavenson.

Mr. Steavenson's letter reads as follows: By the narrow ovens, I

E resume Mr. Fulton means those which are discharged by ram and cooled
y water outside; this, we have always found, causes an excess of moisture
amounting to 4 or 5 per cent., whereas with the round oven it does not
exceed the half of 1 per cent., when cooled before being drawn.

If the narrow ovens are burned close so as to produce by-products, it
gives a solid lumpy material which works badly in the blast furnace.

Messrs. Newton, Chambers and Company, of Sheffield, say they are
successfully drawing off the by-products from the floor of the open burning
beehive oven; this may depend on their having an open free-burning coal,
but we have not yet succeeded in doing it with the rich-burning coal of
Durham, and when we get 64 per cent, of good coke and all the steam which
is required for drawing 1,000 tons per day, and pumping a large feeder of
water from 600 feet, we seem to have accomplished a fairly satisfactory
result. A. L. STEAVENSON.

From the arrangements of the beehive coke ovens of the Messrs.
Bell Brothers, England, it will be seen that the hot gases from these
ovens are conveyed through a central conduit and carried under
boilers, affording steam for winding coal, pumping water, and other
uses. Similar applications of the waste heat of coke ovens have
been made in Scotland and on the continent of Europe.

Since the above was written, very commendable progress has
been made in England and Scotland in improving the beehive coke
ovens, and in the introduction of several plans of the retort coke
ovens with the saving of the by-products.

Use of Waste Gases for Steaming at Pratt Mines, Alabama. — In

America, these waste gases have been utilized at a few plants in a
similar service — generating steam. Mr. E. Ramsay, mining engi-
neer of the Tennessee Coal, Iron, and Railroad Company, describes,
in a paper read before the Alabama Industrial and Scientific
Society, the method in use at the Pratt mines:

"In order that the construction and mode of operation of the
plants now in operation may be readily understood, I have prepared
plans of one of the plants to which reference will be made in this
paper, Fig. 15. As noted heretofore, the ovens from which the
gases and heat are derived were built some years ago and were in
operation at the time work was commenced. The first part of the
work undertaken was the construction of the longitudinal main
flue, which is cylindrical in section and placed immediately to the
rear of the ovens. A few ovens were blown out at a time, and as
the flue was built and connection made to each oven, these ovens
were again put in blast and others blown out, and so on until the
flue had been built and connections made to the entire battery of
twenty-five ovens. This main flue is 3 feet 6 inches internal
diameter, has 4-inch walls on bottom half and 9-inch walls on top
half, and is built of firebrick furnished by the Bessemer Firebrick
Company, of Bessemer, Alabama. At first thought, it may seem
that the walls are too light for a flue of such diameter, but when one
reasons that this flue is cylindrical in shape, which gives the greatest

170

TREATISE ON COKE

possible strength for the amount of material used, the objection
does not have the same force. At all events, it has given no
trouble except on two occasions, when a few bricks fell out of the
walls and into the flue at the juncture of one of the small flues
which connect it with the ovens. When the clay and earth filling
was removed from the rear of the ovens to make room for the

main flue, it was found, as was expected, to be quite hard burned,
and especially that part resting on the oven walls proper, which
was as hard burned as an ordinary red brick. This hard material
was nicely cut out to a section equal to the half circle of the exter-
nal diameter of the flue, the bottom half of which was laid in it,
using the cut-out section as a form and a loamy clay as mortar.

TREATISE ON COKE 171

The upper half of the flue was then laid, using the ordinary wood
centers, which were moved along as the flue was completed. Over
the upper half of the flue, a layer of about 6 inches thick of well-
puddled clay was put on, which, when the heat was turned on,
was burned into the hardness of a red brick. This plan was adopted
as a cheap means of reenforcing and adding strength to the walls
of the flue and making it so that, if a brick or two did fall out, it
would be quite probable that the flue would continue to do duty
until a convenient time for making repairs could be had. In both
of the instances where the flue gave way, work was continued for
several days before repairs were made. As is shown by the plan,
in transverse and longitudinal sections, the main flue is built in
contact with the rear walls of the ovens and a connection is made
to each oven at the point of contact by a cylindrical firebrick flue
12 inches in diameter and about 20 inches long.

" There are two boiler plants of the design, size, and construction
shown in plan in operation at Pratt mines, and each receives the
heat and gases from its individual battery of 12-foot bank beehive
ovens of the usual American construction. Each plant consists
of two batteries of 46" X 26' boilers, with two 16-inch flues each,
and is situated midway and to the rear of the ovens in such a position
that the transverse center line which passes through the center
of the thirteenth oven, counted from either end, is also the center
line of the boiler plant. The boilers were placed in the center of
the bank of ovens for the reason that the closer they were placed
to the ovens the less the distance would be which the gases would
have to travel, and consequently the less would be the loss of
the initial heat of the gases by radiation. To illustrate: the
boilers might be placed so far from the ovens as to cause the gases
to part with all the initial oven heat before arriving at the boilers,
and in such a case the benefit derived would be alone in the com-
bustion of the gases at the boilers, with the proper admixture of
air, in a manner similar to the burning of gases from the blast
furnaces under boilers and in hot-blast stoves. This being the case,
it is apparent that, unless the conditions will not admit of it, the
boilers should be placed as close to the ovens as possible. The
boiler settings, as will be seen from the drawings, are of the ordinary
type, with the boiler fronts and grate bars omitted. To have used
grate bars, in order to allow of hand firing with coal, would have
complicated the plant to an extent which the benefits to be derived
would not have warranted. As noted in a previous portion of this
paper, grate bars were used in the first experimental plant erected
at Pratt mines, and in that case they were rapidly destroyed by the
incandescent gases passing over them. To have obviated this
trouble it would have been necessary to admit the gases back of
the grate bars, and in such a case that part of the boiler immediately
over the bars would have been practically dead space ; or a furnace
might have been built, to one or both sides of the boilers, in such

172 TREATISE ON COKE

a manner as to admit the heat and gases at the same point as they
are now admitted in the plant described in this paper.

" In order that each battery might be worked separately, or both
at one time, an independent flue from the main flue and discharging
under the battery is provided, as shown in the plan, and in each
of these branch flues, which are of the same diameter as the main
flue, a damper was placed in the first plant built; but after working
practically for several months it was found to be almost unneces-
sary, as the opening of the breeching and cleaning doors at once
stops the draft and, consequently, the flow of gases, and if the
shut-down was to be for any length of time, it would be an easy
matter to close one of the flues with a temporary brick wall, such
as is used in closing coke-oven doors at each drawing. That it
is only a matter of a few minutes' work to open these doors
and take off the oven dampers has been demonstrated on several
occasions when it was desired to stop the flow of gas and heat
to the boilers. In fact, "this can be done as expeditiously almost
as a damper, large and unwieldy as it would necessarily be, could
be manipulated.

"The amount of steam-actuated machinery at this mine, shaft
No. 1, is very large, and requires a great amount of steam for its
operation. Before the utilization of the waste heat and coke-oven
gases in the making of steanij this plant used monthly about
1,500 tons of coal,, or 7^ per cent, of the entire output of the mine
for boiler use. This, at $1 per ton, represented a monthly loss of
$1,500 for boiler coal, or about 7^ cents per ton of coal on the
entire output. So long as the selling price of coal was reasonably
remunerative, this large outlay for boiler fuel was not felt so much,
but as the selling price constantly became less and less, it was
imperative that something should be done. Then work was com-
menced on the boiler plants at the bank coke ovens, and so suc-
cessful has been their operation that the coal used at the old boilers
has been reduced to 300 tons per month. When the amount of
labor used at the coal-fired boilers for firemen and ash wheelers,
together with the expense of grate bars and general wear and tear
is considered, it is no exaggeration to say that the coke-oven
boilers have effected a monthly saving of $1,500, or $18,000 per
annum. By utilizing the gas from another block of twenty-five
ovens, the entire plant could be supplied with steam without using
any coal whatever, except a little on Monday mornings, when
the ovens are cold from standing over Sunday; and even this
could be obviated by drawing and charging a few of the ovens
on that day."

From the evidence of the economy in these methods of utilizing
the waste gases from plants of beehive coke ovens in affording heat
for generating steam, it is evident that it will be well to consider
these examples on the lines of economy, especially in erecting
new plants of coke ovens.

TREATISE ON COKE

173

The Ramsay Patent Beehive Coke Oven. — The design of the Ram-
say oven is to secure a hard-bodied coke, to prevent the production
of black ends in the coke, and, by means of its bottom flues affording
increased heat, to coke the dry coals or coals low in volatile matter.
The high temperature of this oven assures a hard-bodied coke, which

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FIG. 16. RAMSAY PATENT BEEHIVE OVEN

is most desirable for use in blast-furnace operations, as it resists dis-
solution, in its downward passage in the furnace, from the ascending
hot carbonic-acid gas. This hard-bodied coke is secured by the use
of all the gas evolved in coking and burned in the oven flues.

Fig. 16 shows the detail of this oven as built at Byrendale
Coke Works, in Elk County, Pennsylvania; (a) is a plan showing
the arrangement of the flues; (6), (c), and (d) are cross-sections.

174

TREATISE ON COKE

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TREATISE ON COKE

175

The following is the explanation of the reference letters used
in connection with the drawings, Fig. 16, showing the construction
of the Ramsay patent beehive oven: a, body of oven; b, front wall
of oven; c, wall between center flue; d, stack in rear of oven;
e, trunnel ring; /, oven door; g, top tile bottom of oven; h, damper
in stack; i, j, composition air-tight packing; k, bottom tile of
oven ; /, two horizontal flues extending from front of oven to stack
at back of oven; m, stack in rear of oven; n, covering of the double
flues /; o, inlet front flues from bottom of outlet flues; p, inlet back
flues from bottom of outlet flues; q, r-, s, t, u, v, w, radiating flues
under oven; x, pillars between flues under oven; y, four inlet flues
from oven to flues; z, top covering tile on top of flues.

Mode of Operation. — Coal is charged the same as in a common
beehive oven at e and leveled, the opening e and door / are closed,
and the damper h is partially closed when ignition takes place.
/ and h are regulated as occasion demands. The operation of the
flues is as follows: the gases generated in the oven enter flues y,
descend o, radiate through s, q,r,u, and t into parallel flues /, and
escape through the stack m\ when the oven is burned oft", the coke
is watered in the oven and then drawn by hand in the manner
commonly employed in drawing, the ordinary beehive oven.

COMPARATIVE AVERAGE ANALYSES OF COKE MADE IN RAMSAY
AND COMMON BEEHIVE OVENS

Moisture
Per Cent.

Volatile
Matter
Per Cent.

Fixed
Carbon
Per Cent.

Ash
Per Cent.

Sulphur
Per Cent.

Phos-
phorus
Per Cent.

Ramsay
Beehive . ...

.02

.17

.75
1 58

89.28
87 53

9.95

10 72

1.05
1 12

.024

025

NOTE. — These analyses were made by the Metallurgical Laboratory,
545 Liberty Avenue, Pittsburg, Pennsylvania.

Comparison of Wages. — Ramsay. — Charging, .05; leveling, .12;
drawing, .99; total, $1.16. The average charge per drawing is
6.645 tons, then $1.16 -=- 6.645 = 17.5 cents per ton.

Beehive. — Charging, .05; leveling, .11; drawing, .77; total, $.93.
Average charge per drawing is 3.55 tons, then .93 -r- 3.55 = 26.2
cents per ton, a saving of 8.7 cents per ton in favor of the
Ramsay oven.

In considering the relative economy of operating different types
of ovens, the first cost is an important item which must be taken
into account.

The following is an estimate of materials and cost of the beehive
and Ramsay coke ovens:*

*The relative work of the beehive and Ramsay ovens, with all other
matter, has been furnished by Mr. Geo. S. Ramsay.

176 TREATISE ON COKE

STATEMENT OF MATERIAL AND COST FOR THE BEEHIVE OVEN

3,100 crown brick at $32 $ 99 20

1,800 liners at $32 57 60

1 set of fronts at $1 1 per set 1 1 . 00

900 red brick at $9 8.10

500 red brick for ring wall at $9 4 . 50

118 floor tile at $95 11.21

1 trunnel head at $3 3 . 00

1 trunnel-head ring at $3 3 . 00

Frame 6 . 00

Labor 239.21

Extra labor and supplies not mentioned above 59 . 70

Total.. ..$502.52

MATERIAL NECESSARY FOR ONE RAMSAY PATENT COKE OVEN

FIREBRICKS

3,000 9-inch quartzite bricks for bottom flues
2,500 9-inch quartzite bricks for side flues

5,500 9-inch Q. T. Z. at $21 per M $115.50

1,900 12-inch Juniata liners at $35 66. 50

2,900 12-inch Q. T. Z. crown bricks at $45 130. 50

190 8" X 3" X 18" Q. T. Z. covering and bridge tiles at 13

cents 24 . 70

20 6" X 6" X 18" Q. T. Z. blocks at 20 cents 4. 00

130 12" X 12" X 2f" floor bricks at 10 cents 13.00

56 12-inch Q. T. Z. special arch bricks for flues at 20 cents 11 . 20

8 Juniata jamb blocks at $2.50 20. 00

2 Juniata R. and L. skews at $2 4 . 00

5 Juniata arch bricks at $2 10 . 00

1 trunnel ring 3 . 00

Total $402. 40

RED BRICKS

1,000 bricks for bottom ring 1

3,500 bricks for chimney \ K AM + *u\ a KA ™

700 bricks for pier f 5'400 at $1° $ 54.00

200 bricks around door J

FIRECLAY BRICKLAYING AND ASBESTOS

10 tons of fireclay, including freight, at $7 $ 70

7 sheets of asbestos 44" X 44" X f", 360 pounds at

5 cents 18

Bricklayer and helpers 90

178.00

STONEWORK EXCAVATION AND FILLING

40 perches of stone work at $4 $160

10 yards of excavation at $1 10

45 yards of filling at $1 45

1 capstone for pier 1

216.00

'3US OKA

! l-

3 "Concrete-^

Ccke Gas inlet -

Super Heated Steam or Air Inlet -
COKE CONVEYOR AND QUENCHING

(a)

17303— v

FIG. 17. DAUBE'S

-''iv? ^r-0'«>»>;j-j^* *o* ~ " ~ \*' Concrete Under J | ! "' rj"

:li--TV'*-»'->'.k>i^J Fire Brick Floor j j ! ! I

C'latnbep "W --••^•->i-"V' ! !^

k — aV-^

tion

-"-A

-DRAFT COKE OVEN

TREATISE ON COKE 177

IRONWORK

4 6-inch I beams at 6 feet long — 24

feet at 15 pounds 360 pounds

1 20' X 9" girder rail with distance

pieces 900 pounds

1 cast-iron door frame 360 pounds

1 cast-iron cover-plate 50 pounds

4 wrought-iron anchors 30 pounds

1700 pounds at 3 cents 51 . 00
Total, $901 . 40

Mr. Ramsay estimates that under ordinary conditions this oven
can be built for $675. Under normal conditions the beehive oven
costs $250 to $300.

Daube's Economic Down-Draft Coke Oven.* — The accompany-
ing illustrations, Fig. 17, show the details of a coking oven invented
by Oscar Daube, of New York, having for its object an improvement
in the quality of by-product coke. The oven is built on a beehive
plan. Under each one is located a combustion chamber operated
under forced draft with coke-oven gas or fuel. This results in
coking from the bottom up, while the waste gases from the com-
bustion chamber pass up the rear, entering the oven above the coke
bed under pressure, which causes the coking to take place from the
top down and 'from rear to center. The gases generated in the
coking process are drawn through flues that pass down the sides
and also under the floor of the ovens, giving off their radiant heat
on their outward passage to the coke in the oven. It will thus be
seen that the coking process takes place from the bottom up, top
down, and from sides to center. The process is claimed to be rapid,
completing in 24 hours a charge of 6^ long tons. The coke obtained
is said to be of first-class quality, running from 88 to 92 per cent,
carbon and yielding 67 to 72^ per cent, of coke.

The manner of withdrawing the gases at the side and bottom
of the oven has for its object the decomposition of the heavy hydro-
carbons. These, coming in contact with the incandescent coke,
decompose on their outward passage, adding a percentage of carbon
to the coke; hence, the large yield of coke per ton of coal. The
yield of tar is correspondingly reduced from 12 to 14 gallons per
. ton to from 4 to 5 gallons. The quantity of gas recovered is approx-
imately 5,000 cubic feet per ton, the balance being used for heating
the ovens. This recovery compares favorably with the amount now
being obtained by other by-product coke ovens. The ammonia
saved amounts to from 25 to 35 pounds per ton of coal, depending,
of course, on the percentage of nitrogen in the coal coked. The
above results are on a basis of a good coking coal, capable of coking
by any process. There are, however, large areas of so-called

*Engineering and Mining Journal, November, 1902.

178 TREATISE ON COKE

non-coking or poor-coking coal that up to date none of the present
coke ovens have successfully coked.

The economic down-draft coking process has been developed
on the opinion held by Sir I. Lowthian Bell, and others, that the
cause of the poor-coking or non-coking qualities of coals lay in the fact
that they are low in disposable hydrogen, and which in slow ovens
volatilizes before the coking stage is reached. This theory is
claimed to have been proved correct in this process, which, owing to
its ability to generate a high uniform heat at the beginning of the
coking operation, brings about the fusing or coking stage before
the disposable hydrogen is volatilized. The inventor states that a
number of western coals heretofore considered non-coking have
been successfully coked by the economic process. The cost of
these ovens, independent of by-product recovery plant, is said to
be only slightly higher than that of the ordinary beehive oven.

IMPROVED HEMINWAY PROCESS*

This improvement relates to the method of coking in a beehive
oven, and has for its object not only the production of a good
sound metallurgical coke from so-called non-coking coals, but also
the improvement of the practice of coking the well-known grades
of coking coal.

It is generally admitted that a good coking coal must contain
from 20 to 30 per cent, of volatile matter; it must be low in ash and
sulphur, and when subjected to a coking heat must fuse or become
pasty, and while in this pasty condition it must give up its vola-
tile matter in such form that during its evolution from the pasty
mass of coal it will push a number of carbon particles together so
as to form strong cell walls, separated from one another by pores.

Suppose that the volatile matter in a coal is over 40 per cent. ; it
naturally follows that one must change or modify the ordinary
practice followed in beehive ovens, because the greater volume of
volatile matter would increase the size of the pores and thus weaken
the carrying strength of the coke, unless the strength of the cell
walls was correspondingly increased; that is, provided that the
rate of evolution of volatile matter was the same in both cases.
But suppose that the volatile matter in the latter case is evolved
at a much greater rate, might not this rapid evolution have a ten-
dency to cause more pressure in the oven and thus close the pores ;
in fact, might it not even change the shape and regularity of the
cells as well, thus producing a coke too dense and one that would
not absorb the hot gases in the blast furnace under usual conditions?
I consider it possible to obtain good results from coke whose cell
structure is not exactly similar to the recognized form. I also

*Dr. R. S. Moss in Mines and Minerals, April, 1901.

TREATISE ON COKE 179

consider it possible to alter the cell structure of a coke at will during
the time of coking by an intelligent manipulation of the pressure
in the oven, which can very easily be accomplished by the use of
my improved method of coking.

It is well known that the fusibility of a coal does not depend
on the volume of volatile matter present in the coal ; however, the
greater the fusibility of a coal, the greater is the range to which it
lends itself for easy change of the size and arrangement of its cells ;
but what effect does this have on the carbon regarding its efficiency
for blast-furnace work? Suppose that I produce a very porous
and a very dense coke from the same coal, does it not follow that,
although the percentage of fixed carbon is the same in both cases,
the efficiency under the same conditions in a blast furnace will
vary between wide limits; but is this the fault of the material or
the method of operating the blast furnace? The same heat units
are represented in both the porous and the dense coke, they are
both strong enough to bear the usual burden of ore, and yet the
proportion of coke to ore is very much greater in one case than in
the other; this assumes that carbon in all its various forms, as
found in coke, will develop the same efficiency. But does it? If
oxidized directly to carbonic acid its efficiency must necessarily be
the same, but as a matter of fact two cokes of exactly similar
analyses give different efficiencies ; what is the cause ? Clearly this
can be readily ascertained by making a simple analysis of the
gases escaping from the blast furnace. It will be found that the
ratio of carbonic acid to carbon monoxide is higher in the gases
from the coke showing the highest efficiency, and vice versa; but
why should one coke give a higher efficiency than another where
the fixed carbon in both is equal ? Obviously, oxidation of the fixed
carbon is not equal, and as oxidation depends on the air supply,
all other conditions being the same, the pressure of air, or the vol-
ume, or both, must be changed; but here again is a limit to which
we can either increase or decrease pressure, or volume, or both, to
advantage ; but as the limit lies within very wide margins it will
be found, in practice, that equally good results may be obtained
with either a dense or a porous coke, provided that they both hold
the burden, by manipulating the air supply either as regards pres-
sure or volume to suit the coke.

Let us return to our coke ovens. When I took charge of the
Universal Fuel Company 's plant I found a battery of four experi-
mental ovens in operation under the Heminway process; to these
ovens a by-product plant had been attached; the arrangement
was such that the gas was taken off from the t runnel head, thence
to a small hydraulic main placed at some considerable distance
from the ovens, thence through a Root exhauster to a Pelouze &
Audouin's condenser, from there through a scrubber, and thence
measured through a proportional meter to a purifier and on to the
holder. I found this arrangement both useless and dangerous.

180 TREATISE ON COKE

Good hard coke was being made from western coals and everything
appeared favorable as regards the matter of coking.

By the Heminway process, air, hot or cold, was blown into the
oven just above the top of the coal. If the oven was rather cold,
or the charge did not readily ignite, hot air was used; the air
was heated to 600 or 700° F. by being passed through firebrick
checker work in a furnace external to the oven, thus aiding combus-
tion. The amount or volume of air, either hot or cold, was not
regulated in proportion to the amount or volume of the volatile
matter that was given off from the coal; hence, the object aimed
at was not gained at all times. If an oven appeared hot, the air
was put in and the oven was blown continuously, resulting in
nothing more than further heating the air, which, passing off from
the trunnel head, carried considerable heat from the brickwork,
hence cooling down the oven so much that after the expiration of
a few hours the oven was very much cooler than when charged.
The coal did not coke, and the inevitable result of an oven making
breeze and not coke was obtained. This had been the case time
and again; the cause assigned by those in charge was deterioration
of the coal used, due to the weather, or perhaps it might be the
effect of a few days longer on the road from the mine to the works,
or it might have got wet in transit, etc. ; be that as it may, while
we all know that coal does deteriorate if exposed to atmospheric
changes, yet I have never heard of any coal undergoing such
remarkable changes in such a short time.

It has been found that, while the Heminway method does
increase rapidity of combustion, the rate of coking is seriously dis-
turbed throughout the mass of coal; for instance, the top layer of
coal is coked long before the bottom, hence, at the high temper-
ature maintained by this method, the coke or carbon in the upper
part of the oven is burned while waiting for the lower layer to
coke. This is as might be expected; coal and coke are bad con-
ductors of heat, hence the rate of heat penetration throughout the
mass of coal is disturbed. The upper layers coke rapidly without
giving a corresponding increase to the lower layers.

Let us assume the normal conditions found in beehive ovens:
5 to 7 tons of coal are charged into the oven, the coal is leveled off
and the door walled up, coking takes place in the usual way and
the oven is drawn, we will say, in 48 hours; black ends are noticed
on the bottom; therefore, the coal has not been thoroughly coked.
If a sample of this coke is taken from top to bottom, we shall find
that the volatile matter will increase from above downwards. Now
suppose that this same oven is attached to the Heminway process,
again charging the same amount of coal — in fact with all conditions
remaining the same — hot or cold air or both are blown into the
oven as deemed best under the circumstances, so that complete
combustion takes place inside the oven; it naturally follows that
the temperature of the oven, at least the space within the area

TREATISE ON COKE 181

of combustion, will increase at a much quicker rate than in the
first case; hence, all other conditions remaining the same, it follows
as a matter of course that the increased disproportion of heat
distribution in the latter case must tend to set up an unequal rate
of coking throughout the mass. Supposing that the oven is drawn
just as soon as the top is well coked, the yield of coke will be high,
yet it will vary in hardness and amount of volatile matter from
above downwards, showing large black ends, practically nothing
but fused coal on the bottom; then again, if we continue to coke
until the whole of this volatile matter has been eliminated and the
coal is thoroughly coked to the bottom, we shall find our yield
much less than the loss of volatile matter above would indicate,
due, in this case, to the coke having been consumed on top. This
teaches that the ideal coke oven must, if possible, be evenly heated;
it must evenly maintain that heat so that the whole mass may be
completely coked, as nearly as possible at one and the same time.
If our material were a good conductor of heat the problem would
be very much easier, but as we must depend on the heat radiated
from the firebrick walls and bottom of our oven, it takes consider-
able time before that heat and the heat of combustion combined
penetrate through the mass of coal; this in a beehive oven; in a
closed oven the trouble is not exactly the same, as this latter
method is one of distillation by means of a furnace external to the
oven. To overcome the difficulties met with in the Heminway
process I have made a number of improvements, which are herein
set forth and discussed.

Instead of blowing air direct from an opening having the exact
diameter of the pipe through which it is conveyed, I enlarge the
exit by making it elliptical in shape, raised slightly on the lower
side instead of horizontal, thus blowing the air in a slightly upward
direction in the oven and at a sufficient height above the mass of
coal to protect combustion of the fixed carbon, by a cushion or
layer of volatile matter between the coal and the air supply; at a
point 3 feet at least from the center of the air exit I add a second
air supply also elliptical in shape and placed almost in a horizontal
plane, thus completing combustion of the volatile matter that
escaped the lower supply of air. It is obvious at once that the
form of my exit will insure a better and more even mixture of air
and combustible gas than when the exit is round. It prevents cut-
ting or channeling of the volatile matter and gives a better diffusion ;
then again, it is well known that to obtain complete combustion a
considerable excess of air is required; hence, if we depend entirely
on one air supply, a considerable volume of inert nitrogen must
be thrown into the oven, thus absorbing heat and carrying it off
at the trunnel head. If complete combustion is not obtained,
a large amount of combustible volatile matter will pass out of the
trunnel head and be consumed in the open air without giving any
heat to the brickwork in the oven. By adding a secondary air

182 TREATISE ON COKE

supply it does not become necessary to blow as much air into the
oven from the lower pipe. Combustion of part of the volatile
matter takes place ; the heat produced by this combustion is trans-
ferred to the whole of the gases; hence, the unconsumed volatile
matter reaches the secondary air supply at a higher temperature
than would otherwise be the case; hence, such an excess of air is
not required to obtain complete combustion as is the case with only
one air supply, and the whole of the combustible matter is con-
sumed inside the oven, thus preventing loss of heat due to combus-
tion on the outside of the oven. This is all very well so far as it
goes, yet it alone only increases the disproportion of rate of coking
throughout the mass of coal in the oven, and hence aggravates
rather than lessens the trouble met with in the Heminway process
of coking; for, with this increased heat above the coal, the top layer
of coal is coked much more quickly than in the Heminway process,
and even long before the coal on the bottom of the oven has given
off its volatile matter; hence, we must either draw an oven with
coal on the bottom not coked at all, or we must run it until coked,
when the fixed carbon on the top, or rather the coke, is being con-
sumed and the top is ashed over, reducing our yield very seriously,
as well as increasing the percentage of ash; therefore, one can see
that this improvement in itself is useless. To overcome this diffi-
culty I have built a flue from the inside of the oven just below
the trunnel head, carrying it down the outside of the oven and
under the bottom, starting near the front of the oven and continu-
ing along the bottom to the back, and again passing outside to a
main flue built between the ovens, where the gases may be utilized
for raising steam, and thence to a chimney discharging into the
outer atmosphere. I have built twelve flues under the oven, and
thus equalized the heat from front to back; the front being the
coolest part of the oven in a battery built back to back decided
my taking, or rather starting, in from the front, because the pro-
tection of the other ovens on the sides and back maintains a
slightly higher temperature than in front where the oven is not
protected; hence, the gases at their highest temperature enter the
bottom flues at the coolest part of the oven. By carrying the
waste gases from the top underneath the floor of the oven, I
equalize, to a great extent, the difference in temperature between
the top and bottom of the oven; not only this, but I also increase
the rapidity of evolution of the volatile matter from the bottom,
and thus in a given time remove a greater volume of combus-
tible matter than is possible in the Heminway or old process.
This increased combustible matter requires a large volume of air
for its combustion; hence, I open the top and bottom valves con-
nected with the air supply and thus add the required increase of
air. This increased amount of air and gas, by their combustion,
increases the amount of heat produced ; hence, the waste gases pass-
ing under the bottom of the oven carry a corresponding increase

-TREATISE ON COKE

183

of heat ; the greater volume of air and gas gives a greater volume of
waste gases, all of which are conveyed under the bottom of the
oven, not only equalizing the heat in the mass of coal, but also
increasing the rapidity of coking the coal, thus materially reducing
the time of coking, in addition to obtaining a more even coke and
one entirely free from black ends, to say nothing of the increased
yield which I obtain. I find it an advantage to build a double

ToB/ayr

FIG. 18. HEMINWAY PROCESS IMPROVED BEEHIVE COKE OVENS

floor on the bottom of the oven because of the increased amount
of heat retained than when single. One must also build the floor
of the flues of sufficient thickness to prevent undue loss of heat
below; it must be protected by a sufficient thickness from the
effect of atmospheric changes, as well as climatic conditions, such
as difference in temperature between winter and summer, excessive
rains, etc. The place and location of the ovens will readily deter-
mine what precautions are necessary to retain the heat on the
bottom so as to obtain the most effective work.

184 TREATISE ON COKE

To still further obtain a more intimate mixture of air and gas
in the oven, I have added four openings in the oven on a level
with and in favor of the one lower oval-shaped opening. I thus
throw air into the oven at four separate points equidistant from
each other, thus reducing the danger of unequal and incomplete
combustion; the directions of these four openings are such that
a line drawn from the lower side of each opening will strike a
point just below the trunnel head in the oven. One can easily
see that a very complete mixture of air and gas is obtained. If
necessary, two more openings for the admission of air may be
added in favor of the one upper opening, these openings to be
directly opposite each other and almost horizontal with the face
of the oven; this will insure a secondary air supply that will
thoroughly and evenly mix with the gases coming from below and
result in complete combustion of all volatile combustible matter
escaping from the lower part or strata of combustion.

While this is a great advance over the old method, yet the rate
of coking through the mass is not as even as might be desired! We
have, in this case, our oven hotter at all times on top than on the
bottom and less toward the center than on the bottom; to over-
come this I have arranged to pass either air alone, or air and waste
gas, or waste gas alone, under the bottom and up through the
mass of coal in the oven by means of flues or perforated tile, or
any arrangement that will allow the air or gases 'to pass up through
the whole bottom of the oven; for instance, in my first trial of this
I used the flues built in the bottom of the oven which I designed
for drawing off gas, tar, and liquor; the flues, two in number, are
6 inches wide and 9 feet from back to front; in a 12-foot oven
they are arranged at equal distances apart and are covered with
perforated brick J inch wide on top and ^ inch on the bottom. Air
was blown in the bottom through these flues and, as might naturally
be expected, combustion was very intense over the flues, so much
so that it channeled and rapidly consumed the volatile matter in
the coal directly over the flues. The coal along this line coked very
rapidly, leaving a depression the shape and length of the flue on
the top of the coke due to the quicker coking over the flues and
consequently quicker contraction. Near the front of the oven or
at the point of least resistance to the passage of air, large holes
appeared, through which the air passed readily to the top of the
oven; however, even with this crude arrangement, the coke came
out good; black ends in this case appearing on top and not on the
bottom of the coke. The time of coking was still further reduced,
and I consider, with the perforated bottom and intelligent manage-
ment of all the improvements herein set forth, we shall still further
reduce the number of so-called non-coking coals, besides reducing
time of coking of all coals now coked, coking a 7-ton charge in
36 hours equal to 72-hour coke, improving the quality and increas-
ing the yield so that it runs very close to what is found on analysis.

TREATISE ON COKE

185

The importance of this perforated bottom for the admission of air
or waste gases, or a mixture, cannot be overestimated; but like
all improvements, it can be made worse than useless by ignorant
operation. When air is blown into the bottom of the oven the
volatile matter in the coal is consumed ; at the point of combustion
considerable heat is produced which, passing from below upwards,
distills the volatile matter above, and this increased yield of volatile
matter increases the volume of combustible gases; hence, a greater
volume of air is required. This air is supplied either through the air

a-Grcu/afing blast

8"5uct/on Pipe

FIG. 19. ARRANGEMENT OF FLUES IN IMPROVED BEEHIVE OVENS

flue on the top, or, if the heat is not fairly even, a part or the
whole of the combustible gases is carried to the bottom of the oven
where they come in contact with air blown into the bottom; hence,
combustion of the volatile matter takes place, protecting the fixed
carbon on the bottom of the oven; and yet by the passage of this
hot burned gas it distills the volatile matter remaining in the mass
of coal above the coke on the bottom, and the heat passing
rapidly and evenly from top to bottom and from bottom to top,
produces an even rate of coking throughout the mass of coal. I was
led to this improvement through chemical methods which I have

186

TREATISE ON COKE

devised for the removal of sulphur and which demand a quick
temperature throughout the mass of coal to decompose the chem-
icals used and bring about the necessary chemical reactions, without
injury to the fixed carbon.

The battery of twenty-four ovens has been built after the plans
of the writer, as shown in Figs. 18 and 19. These ovens are now in
operation producing results which excel even my anticipations.
I am able to coke a 5-ton charge of so-called non-coking Illinois
coal in 24 hours, and the coke is superior in quality. I am able to
use duff which costs 25 cents per ton at the mine, but am now
using pea coal on account of the moisture in washed duff at this
time of the year, about 30 per cent., which is frozen and takes too
long to draw off in the oven.

The following are analyses of the coal and the coke:

ANALYSES OF ILLINOIS COAL

Moisture

Volatile Matter

Fixed Carbon

Ash

Sulphur

2.30

33.58

56.93

7.19

1.32

5.71

32.61

52.26

9.42

1.93

4.50

31.60

56.90

7.00

1.10

4.35

31.16

56.79

7.70

1.30

4.57

31.53

55.06

8.84

1.13

COKE ANALYSES

Moisture

Volatile Matter

Fixed Carbon

Ash

Sulphur

.10

.80

87.37

11.73

.90

.09

.64

88.89

10.38

.76

.08

1.03

88.71

10.18

.35

.10

1.64

87.45

10.81

The whole of this work, which I have devised and carried into
practice at this plant, has been especially arranged to treat all
kinds of coal, and is working with the greatest possible success.
All my improvements herein described are the sole property of
Mr. L. Z. Leiter; my by-product gas plant is working with the
greatest success. It is the first time coal gas, tar, and ammonia,
in addition to the metallurgical coke, have been successfully pro-
duced in a beehive form of oven.

Newton-Chambers System. — In 1895, thirty Newton-Chambers
beehive coke ovens were put in operation by the Latrobe Coal
and Coke Company, near Latrobe, Pennsylvania. For a time, they
were operated as by-product saving ovens, but after a brief period
the saving of by-products was abandoned. The ovens are now
being operated in the usual way as beehive ovens. They are of
about the same dimensions as the standard class of these ovens in

TREATISE ON COKE

187

the Connellsville field, only the doors have been greatly widened
to introduce a system of mechanical coke drawing, from the design
of Mr. Thomas Smith, of the ThornclifTe Iron Works, near Shef-
field, England, patented in 1891.

Fig. 20 shows a portion of a bank of thirty beehive coke ovens
with the appliances for saving by-products. As has been stated,
the effort at saving by-products has been discontinued. It is not,
therefore, necessary to enter into a description of these appliances,
as it was found undesirable to continue the effort for saving the
by-products of ammonia salts, oil, or tar products, and gas.

Many efforts have been made to supersede the heavy and hot
manual labor of drawing coke, by automatic machines, in the

FIG. 20. LATROBE COKE OVENS

round or beehive coke ovens. So far, little progress has been
made in a practical way in coke drawing. The machine for draw-
ing coke at the Latrobe coke ovens, shown in Fig. 20, is the most
successful effort thus far made in this direction. It is reported
that a single man operating this extractor can draw four of the
large 12-foot ovens per hour.

The Smith coke drawer, Fig. 21, consists of an extractor or coke
drawer on one truck, coupled with a second truck carrying a small
upright boiler, which runs on a track parallel to the coke ovens.
The extractor consists of an engine, operating a bar a with a wedge-
shaped plate or shovel b.

This shovel is pushed under the coke in the oven, the coke falling
over the back surface of the wedge. The engine is then reversed

188

TREATISE ON COKE

and the bar with its shovel drawn out, bringing the coke with it.
Along the front of the ovens there is an apron or endless con-
veyer into which the coke falls. The coke is then conveyed to
the end of the block of ovens and delivered into railroad cars.

The Hebb coke drawer* is the invention of Mr. John A. Hebb,
of Hopwood, Pennsylvania, and is in successful operation at the
Continental, No. 1 plant, of the H. C. Frick Coke Company. In
building this machine, it has been the inventor's object to incorpo-
rate in the mechanism the movements made by a man in pulling
coke from an oven.

In Fig. 22 (a), the small house at the right of the machine con-
tains the electric motor, which, together with the coke-drawing

FIG. 21. SMITH COKE DRAWER

mechanism, is mounted on a truck adapted to run on a track
along the yard in front of the ovens.

The mechanical details of this coke drawer are best shown in
Fig. 22 (b) and (c), the former being a vertical section on the line
of the scraper or rake beam, transversely of the track on which
the machine runs; and Fig. 22 (c) is a vertical section at right
angles to that of Fig. 22 (b), and also through the center of parts
mounted on the revolving table. Referring to Fig. 22 (b) and (c),
the main truck a supports a revolving table b that runs on rollers c,
the table being provided with a circular track d. Connected with
the electric motor is main shaft e, which by means of bevel pinion /
drives vertical shaft e' by meshing with bevel wheel /'. Extending
at right angles with shaft e, and on about the same level, is shaft g.

*Extracted from Mines and Minerals for February, 1904, p. 304.

TREATISE ON COKE

189

From these main shafts all of the various operations of the machine
are transmitted through gearing, clutches, and levers.

The turntable b is rotated in either direction by a hand wheel
connected by gearing meshing into worm-wheel h. Mounted on the
shaft with h is a pinion i which engages a circular rack i' mounted
upon truck a.

The description of the scraper or rake mechanism is readily
apparent upon reference to the illustrations. The rake beam / is
supported on rollers mounted on standards, at each side of central
shaft #', and which are secured to turntable b. At the upper end
of shaft e' is keyed a bevel pinion k that meshes with bevel gears kf ',
one on either side, and running in opposite directions, loosely on

FIG. 22. HEBB COKE DRAWER

shaft /. Beyond gears kf on each side is a friction drum m keyed
to shaft /. Also keyed to the same shaft are driving pinions n that
engage racks secured to each side of the rake beam /. When either
friction drum m is brought into frictional engagements with its
adjacent gear k' it will transmit motion to shaft /, in one direction
or the other, according to which drum is utilized. The shifting
operation of the drums is secured through lever o, which, in an inter-
mediate position, holds the friction drums clear of the gears. By
this means, upon holding one of the clutches in contact, the
beam may be extended into the oven to the desired distance,
and upon using the other clutch it may be withdrawn. Beam /
rests on rollers, so that its weight is not carried by pinions n.
Above the beam is a roller that provides an upper bearing
for the beam and holds it in engagement with the driving

190

TREATISE ON COKE

FIG. 22. BESB COKE DRAWER

TREATISE ON COKE 191

pinions. The forward end of the beam is provided with a
pivotally attached rake head p, adapted to fold backwards on
coming in contact with the coke when it enters the oven, and
to be automatically extended to its upright position [as shown in
Fig. 22 (J)] by the tension of a spring at the back end of beam.
A rod connects rake head p with the spring.

The inner (end nearest oven) end of beam is raised and lowered
as follows, shown in detail at the left of Fig. 22 (c) : Clutch q,
which is keyed to the constantly moving shaft e', is adapted to
engage bevel gears r and rf, these latter being loosely mounted on
shaft e' '. Clutch q is raised or lowered by lever 5 provided with
a hand lever. Gears r and r' engage bevel gear t keyed to shaft /',
on which is worm u, Fig. 22 (b). The worm engages toothed
segment v having a lever arm. Upward or downward movement
is imparted to the inner end of the rake beam through lever arm in/
and arms w, the latter carrying under and upper rollers as shown.
Thus, the parts described permit the machine to reach any part
of the oven for the removal of the coke.

Other devices are employed for the purpose of moving the
entire apparatus along the track either for the purpose of locating
it to the right or left of the central position in front of an oven or
for transporting it from one oven to another. The gear to accom-
plish this result is connected with shaft g, which is constantly
revolved by shaft e by means of bevel gears. On shaft g is keyed
clutch x\ gears y and y' are loosely mounted and revolve when
brought into engagement with clutch x. Meshing with gears y
and y is another bevel, not shown, through which, by suitable
connections with a worm on axle z, motion is imparted to wheel z'
and the truck moved one way or the other according to which
bevel clutch x engages. A lever within easy reach of the machine
operator controls this actuating mechanism.

The removal of the coke raked out by the scraper is effected
by a conveyer shown in Fig. 22 (a).

The operation of the machine is effected by one man who stands
on the turntable b and faces the oven door. All the levers are
within easy reach, so that he can control any of the movements
of the machine without changing his position.

Silica Brick. — The following letter from O. W. Kennedy,
formerly general manager H. C. Frick Coke Company, in regard
to the introduction of silica brick, is self-explanatory:

JOHN FULTON, ESQ. UNIONTOWN, PA., March 16, 1904.

My Dear Sir: — Absence from home has delayed reply to yours of 5th.
A man named Bradley, who was superintendent of a silica brick works at
Layton, Pennsylvania, claimed recently to have been the first to suggest
their use to me and to others. He did so, but some time prior to that a
man named Drum had insisted that they would answer the purpose, but
no one paid any attention to them until I took the matter up with Bradley
and began their use against the protest of brick manufacturers, oven builders,

192

TREATISE ON COKE

and about everybody connected with the business. It was two years or
more after this beginning before some brick makers in this region could be
persuaded to abandon the manufacture of clay brick, and then only after
they saw their trade leaving them.

I do not know how many others besides Drum and Bradley thought
they would answer the purpose, but the fact is that I fo.ught the battle for
silica brick in coke-oven construction against odds and opposition that
would have caused many a one to abandon the project, and persisted until
their use became general.

I would estimate the life of a silica crown at from 12 to 15 years. Some
clay crowns have lasted that long, but the instances are rare and were made
many years ago. In the past 10 or 12 years they have ranged from 2 months
to 3 or 4 years. I think it would be entirely safe to say that an average
life would be less than 3 years. This, of course, applies to the Connellsville
and Klondike fields. In some other coking districts I believe they get
along with the clay crowns fairly well. Yours truly,

O. W; KENNEDY.

Coking Experiments and Results. — The following is a synopsis
of experiments, with practical conclusions, made in the manu-
facture of coke in beehive coke ovens in the Connellsville region,
Pennsylvania. These experiments consisted of tests at two coke
works; one had its coal treated in a Heyl & Patterson breaker,
the other was crushed by a pair of rolls; the former separated
the rough slates, the latter broke coal and slate together. Special
attention was given to the effects on the coke from coal treated
in these ways as well as from coal as it came from the mine. Con-
clusions from these tests were arrived at as to the management
of the ovens to assure the best results in the time used in coking
and in the quality of the coke.

To determine the downward rate of progress in the coking of
the coal, measurements were carefully made showing the following
rate of carbonization:

TABLE V
RATE OF CARBONIZATION

Length of
Time in Oven
Hours

Thickness of
Coal Coked
Inches

Thickness of
Coal Coked in
1 Hour
Inch

Length of
Time in Oven
Hours

Thickness of
Coal Coked
Inches

Thickness of
Coal Coked in
1 Hour
Inch

itf

$ +

1 _

It will be seen from this table, as well as from the two illustra-
tions of the downward progress in coking, Figs. 10 and 11, pages
159 and 161, that this process in its beginning is rather slow,
decreasing until the twentieth hour, then increasing until the
twenty -fourth hour, moderating at the twenty-eighth hour, after
which the progress is slow until the close of the operation at the

TREATISE ON COKE 193

seventy-second hour. An examination of the coke products of
48-, 72-, and 96-hour coke shows that the silvery glaze on the
coke is deposited carbon. Occasionally this carbon is thrown on
the coke as soot. These deposits are mainly found on the coke on
the uppermost 15 to 18 inches of the coke made.

The walling up of the door of the oven and closing the charging
port give the following beneficial effects : valuable heat is retained
in the oven and the best results in coking are assured.

The want of sustained heat in the oven from insufficient air
will produce inferior coke accompanied by the undesirable black
ends in the coke. It is manifest that air is admitted into the oven
to supply the necessary oxygen to secure the complete combustion
of the gases evolved from the coal in the coking process. Hence,
the importance of adjusting the supply of air into the oven to meet
this necessity. Too much air will have the effect of cooling the
oven. The largest amount of gas is liberated in the initial opera-
tions of coking, requiring the most ample supply of air, say up
to the twenty-fourth hour; after this the supply of air should be
gradually diminished until the flaming ceases, when the oven
should be entirely closed until drawn.

In these experimental tests, some ovens were intentionally
cooled by allowing them to stand, while others were heated by
covering the charging ports with dampers. The coke from the
cooled ovens was inflated in cellular structure and had nearly an
inch of black ends. The whole charge showed irregular coking,
with a poor quality of coke. The hot ovens produced a first quality
of coke, with good cell structure and the absence of black ends.
Two experiments showed conclusively that the ovens in which the
heat was retained by walled-up doors and closed charging ports
produced coke, 72 hours after charging, that was thoroughly car-
bonized and showed little black ends. From these tests it follows
that a high degree of heat in the oven, maintained throughout the
process of coking, is essential to securing the best results in hardness
of body of coke, in developing its cellular structure, and in pre-
venting the production of black ends.

Another very interesting test of two ovens was made. Two
adjacent ovens were selected, A and B. Oven A was closed at
door and port hole as soon as the charge of coke was drawn out;
it was then allowed to stand 5 hours before recharging. Oven B
was treated in the usual way; that is, it stood about 2 hours before
it was recharged. No damper was used on the charging port and
the door was not walled up until after leveling the charge of coal.
The charges of coal were equal in these ovens, about 145 bushels
or 5.62 tons each. Oven A ignited 8 minutes after charging,
starting off with brisk combustion, becoming quite hot 10 minutes
after ignition. Oven B ignited 32 minutes after charging, starting
off with feeble combustion, becoming quite hot 30 minutes after
ignition. Oven A was completely burned off in 8 hours less time

194

TREATISE ON COKE

after charging than oven B. This comparative test, which is
most important in the manufacture of coke, was kept up and the
reliability of results, as stated, assured.

It was demonstrated that, by using dampers on the charging
ports and walling up the oven doors immediately after the coke
was drawn, the heat was retained and the best results in the quality
of the coke secured.

With increased charges, oven A made its coke during the
same time that oven B, with less charge, completed its operation.
The charge was 5.62 tons, and as there are about 9,000 cubic feet

TABLE VI

No.
of Test

Time of Coking No. 1
Oven, Dampered and
Sealed 3 Hours Before
Charging — 72-Hour Coke

Time of Coking No. 2
Oven, Charged Imme-
diately After Drawing —
72-Hour Coke

Time of Coking No. 3
Oven, Charged in Usual
Way 2 Hours and 10 min-
utes After Drawing —
72-Hour Coke

Hours

Minutes

Hours

Minutes

Hours

Minutes

Average

of gas in 1 ton of this coal and it required 72 hours in oven B to
burn the 50,000 cubic feet of gas, it burned this at the average rate
of 694.4 cubic feet per hour, a slow condition of combustion.
Oven A burned its gas in 64 hours, or at the average rate of 781.2
cubic feet per hour, which emphasizes the value of the hot oven.

In addition to the exclusion of outside air in retaining or
storing the heat of the oven, by walling up the doors to the level-
ing line and dampering the charging port, it is also important
to charge the oven- quickly after the first charge of coke has been
removed. This affords the charge of coal full time in the oven

TREATISE ON COKE

195

to secure the best results in 48- and 72-hour products of coke.
Any loss of heat or time in recharging detracts from the quality
and value of the coke.

In harmony with the foregoing tests, three additional tests
were made to determine the effects of these methods in the manu-
facture of coke:

1. The first set of ovens was sealed immediately after the
drawing of the coke, and allowed to stand 3 hours before charging.

2. The second set was charged immediately after the coke
was drawn out.

3. The third set was treated in the usual way, that is, charged
in its regular turn, but not dampered. This was on an average
of 2 hours and 10 minutes after drawing the coke.

The charge of coal in each oven averaged 142.7 bushels. The
average time that elapsed between the charging of the oven and
its ignition was as follows: (1) first set, 24 minutes; (2) second
set, 51 minutes; (3) third set, 1 hour and 8 minutes.

The time required in coking in these ovens will be seen in
Tables VI and VII.

It was observed that the ovens in the first series maintained a
more rigorous combustion, especially toward the end of each burn-
ing, gaining 5 hours in time over the Nos. 2 and 3 series of ovens.
An additional test was made in the No. 1 ovens, by increasing the
charge of coal 5 bushels. The time of burning was as follows:

TABLE VII

No.
of Test

Time of Coking No. 4 Oven,
Dampered and Sealed 3 Hours
Before Charging— 72-Hour Coke

No.
of Test

Time of Coking No. 4 Oven,
Dampered and Sealed 3 Hours
Before Charging — 72-Hour Coke

Hours

Minutes

Hours

Minutes

1
2
3

57
61
55

30
30

4
5
Average

65
66
61

15
19
10

With the coal charge increased 5 bushels, these ovens were
burned off in about the same time as the ovens in Nos. 2 and 3.

Effects in Physical Properties of Coke Produced by Crushing
the Coal. — Investigations were also made to ascertain the effects
produced on the physical properties of the coke from crushed coal.
(See conditions of crushing coal on page 192.) These tests were
made at two plants, one using coal crushed with slate separated;
the other using coal and its slate crushed together. We will desig-
nate these tests A and B.

Under the conditions of crushing the coal at the coke works A,
it was observed that the lower section of the coke in the oven had

196 TREATISE ON COKE

an infla ea cellular structure. This led to the belief that the ovens
were overcharged and could not burn off as heavy charges of the
fine coal as they could of the run-of-mine. To test this the 72-hour
charge was reduced from 145 to 138 bushels, but this instead of
improving the physical structure of the coke made it more spongy,
causing the ovens to burn off from 10 to 12 hours before the time
of drawing the coke. The coke was also brittle and imperfectly
coked. Complaints of this coke came from several parties. The
charges were restored to 142.7 bushels, very decidedly improving
the physical condition of the coke. The reduction of the charges
worked badly as to the quality of the coke and ihe losing of heat
in the oven. These tests exhibited the difficulty in keeping the
ovens that are charged with broken coal to the desired high standard
of heat.

The average weight of the coal as it comes from the mine is
78.6 pounds per bushel, while the average weight of the broken
coal is 75.9 pounds per bushel. It is therefore evident that a
bushel of the run-of-mine coal is 3.55 per cent, heavier than a bushel
of the broken coal, which means that 1 bushel of run-of-mine coal
makes 1.0355 bushels of broken coal, after the coal has been finely
broken and the refuse separated. It was decided from these experi-
ments, considering the relative bulks of run-of-mine and breaker
coal, that it requires a hotter oven in using the latter coal to assure
equally satisfactory results with the use of the run-of-mine coal.

Swelling of the Charge. — Measurements were made to ascertain
the relative amounts of the swelling of the charges of run-of-mine
and broken coal. These measurements were taken every 30 min-
utes for 5. hours and it was found that the greatest swelling of the
charge took place about 3J hours after ignition. It was found
that the maximum swelling was the same in both series, being
2^ inches in each. It was considered that this expansion of the
charge of coal in coking is mainly due to the swelling of the upper
3 or. 4 inches of the charge, and is not due to the swelling of the
whole body of the charge.

Shrinkage of Charge. — Another test was made to determine the
shrinkage in the height of the coke due to watering or cooling in
the oven. It was found that the shrinkage of a 72-hour charge
of coke is about -^ inch.

Another test was made to determine the relative shrinkage in
cooling the coke in ovens that have been charged with run-of-mine
coal and broken coal. The former showed an average shrinkage
of 5.36 inches, the latter an average shrinkage of 7 inches. The
height of the charge in the former was 26 inches, and in the latter
27 inches. In the first series, run-of-mine coal, the average shrink-
age was 20.70 per cent, of the total height of the charge; and in the
second series, 25.95 per cent, of the total height of the charge.

TREATISE ON COKE 197

Cell Structure. — A test was made to determine the relative
cellular structure in the coke from lump coal and from finely
pulverized coal. The large lump coal made a coke weighing
72.50 pounds per cubic foot, and the finely powdered coal gave a
coke weighing 53.17 pounds per cubic foot, a reduction in the
weight of a cubic foot of coke of 19.33 pounds. Other lumps of
coal were subsequently coked, and the coke from these was corre-
spondingly heavy and evidently of closer cellular structure than
the coke made from the broken coal and pulverized coal. It
follows from these tests that the coarser coal produced a heavier
and denser coke, the lighter and more developed structure being
secured from the powdered coal.

Relative Weight of Coke. — The crushed coal, the crushing having
removed some of the slate and other impurities, produced the best
quality of coke in its physical and chemical properties. Fifty
samples of run-of-mine coke gave a weight of 61.61 pounds per
cubic foot. An equal number of samplings of broken-coal coke
gave a weight of 60.59 pounds per cubic foot, exhibiting a difference
of 91.02 pounds in favor of the latter Doubtless some of the
difference in the weight of a cubic foot of each product is accounted
for in the difference of the cellular structure, but the main element
consists in the purer coke from the broken coal with its impurities
removed.

A test made to determine the relative weights of coke made
from run-of-mine and broken coal, and also to enable a comparison
to be made between 48- and 72-hour coke, gave the weight of a
cubic foot of run-of-mine 48-hour coke as 58.65 pounds, and the
weight of 48-hour coke from broken coal as 56.21 pounds per cubic
foot, or 2.44 pounds per cubic foot lighter than the coke from
run-of-mine coal. The run-of-mine 72-hour coke weighed 61.61
pounds per cubic foot, and the 48-hour coke weighed 58.11 pounds,
or 3.5 pounds lighter per cubic foot.

The following results were obtained from crushed coal, in which
the coal and its impurities were broken together without any
attempt at separation: The weight of 72-hour coke from this
broken coal was 70.88 pounds per cubic foot, and from run-of-mine
coal, 66.81 pounds per cubic foot. It is evident that the broken
coal makes coke 4.07 pounds heavier than that made from run-
of-mine coal. The crushed coal at this place makes a denser coke
than that made from run-of-mine coal. It may be noted that at
one of these works, in the coal-crushing operation, much of the
bone and slate are removed, while at the other Tkrth are crushed
together.

A test was made to endeavor to account for the difference in
weight of the coke made from the coal in its two different treat-
ments in the coke oven. The bone and slate separated at one of
the works were collected and after being finely broken with a

198 TREATISE ON COKE

hammer were restored to the charge of cleaned coal, thoroughly
mixed and charged into the oven. It was found that the coke
produced with this mixture afforded substantially the same weight
of coke as that from the broken coal and its slate from the other
works. Careful test showed that, in 28.70 cubic feet of run-of-mine
coal, 1.8 cubic feet of refuse was taken, or 6.27 per cent. Now,
6.27 per cent, of a charge of 145 bushels of coal would be
9.09 bushels, which equals the amount of refuse existing in a 145-
bushel charge. A cubic foot of coke made from this crushed
coal and slate gave a weight of 62.73 pounds. Comparing this
weight of 62.73 with 61.61, the weight of a cubic foot of coke from
run-of-mine coal, it shows also that the weight of coke from cleaned
coal is increased 1.12 pounds per cubic foot above that of run-of-
mine coal by giving the crushed coal the same quality as when
crushed en masse — coal and slate.

At one of these works, the crushed coal and slate give an
additional weight of 4.07 pounds, while at the other, under like
conditions, the increased weight of the coal is only 1.12 pounds per
cubic foot. The difference in the methods of crushing the coal at
these two works does not fully account for the difference in the
weight of the coke produced. Evidently the difference in the
bone and slate at these two mines will suggest the main cause of
the divergence in the weight of coke produced.

The evidence of these tests shows that the presence of finely
crushed bone coal and slate in the charge of coal will produce a
more restricted cellular structure in the coke. The variations of
cellular structure, as shown by the previous tests, must also involve
variations in the amount of shrinkage, the uncleaned coal at one
works giving a reduced shrinkage below the cleaned coal of 2 inches.

Tests of Coking Properties of Different Portions of Connells-
ville Coal Seam. — A series of tests was made to determine the
quality and physical properties of coke made from the three natural
divisions of the Connellsville bed of coal. These divisions are as
follows: (1) the coal between the 3-foot binder and floor, or
bottom of the seam; (2) the coal between the 5-foot binder and
the 3-foot binder; (3) the coal between the 5-foot binder and roof.

The coal for this test was secured from points in the mine
sufficiently distant to secure a general average. The coke produced
afforded the following weights per cubic foot: (1) from bottom
bench of seam, 57.86 pounds; (2) from middle bench of seam,
72.50 pounds; (3) from upper bench of seam, 82.07 pounds.

Coke from fine coal from the same localities in the mine and
from the same benches of seam weighed as follows : .(1) from bottom
bench of seam, 53.20 pounds; (2) from middle bench of seam,
58.21 pounds; (3) from top bench of seam, 61.79 pounds.

Comparing the above results, it is evident that the weight of coke
made from lump coal is heavier than coke made from fine coal, all

TREATISE ON COKE

199

taken from the same localities in the mine. It is also evident that
the coal from the top bench of the seam affords the heaviest coke, the
middle bench the next heaviest, and the bottom the lightest.

The analyses of the coke made from three benches of this
large bed are as follows:

Fixed
Carbon
Per Cent.

Volatile
Matter
Per Cent.

Ash
Per Cent.

Phos-
phorus
Per Cent.

Sulphur
Per Cent.

Bottom of seam

91.09

1.36

7.55

.010

.558

Middle seam . . .

88.78

3.08

8.14

.016

.690

Top seam

81.28

1.70

17.02

.028 -

.973

As to purity, the coke decreases in quality from the bottom
to the top of the seam.

Axioms. — Diminutive cellular structure in the coke is caused by
insufficient heat in the ovens, and, conversely, a high heat main-
tained throughout the period of the coking process is essential to
the best cellular structure, hardness of body, with the absence of
black ends.

It is a decided benefit to exclude the outside air as much as
possible from the oven while it is standing over between charges,
either by walling up the door or using a sheet-iron shield; also,
it is an advantage to make this interval at least 2 hours, provided
that the outside air is excluded.

It requires a hotter oven to secure the best results in coke when
using broken coal than it does when using run-of-mine coal.

The coarser the coal, the heavier is the coke, and the finer
the coal, the lighter is its coke; the purer the coal, the lighter
is the coke. This is self-evident, as the impurities of the coal are
mainly heavier than the pure coal.

These experiences are from the practice of coking in the Con-
nellsville seam. Other regions will require special studies to secure
the best result in the coke produced.

Where impurities exist in coal, it should have a preparation for
coking by crushing and washing.

CHAPTER VI

THE RETORT AND BY-PRODUCT-SAVING COKE OVENS

Introduction. — Two conditions combined to introduce the mod-
ern retort or closed coke ovens in Continental Europe: (1) Some
of the coals in these countries inherit a small percentage of the
fusing matter so essential in the manufacture of coke for metal-
lurgical uses; hence, the retort oven with its quick heat, utilizing
the small portion of this fusing matter in these qualities of coal,
supplied this important requirement. (2) The desire for supple-
menting the profits of coke making, by saving the by-products of
tar, ammoniacal liquor, and gas, from the gaseous products dis-
charged from the coking chambers of the ovens in the manufacture
of coke.

Evidently this new departure was suggested to coke makers
and oven builders from the operations in the manufacture of illumi-
nating gas, for the gas makers, in the process of purifying their
product, required the elimination of tar and ammoniacal liquor.
It thus became evident to coke makers that the gases evolved from
the coke ovens contained similar products and logically suggested
additional profit in saving them.

It is recorded that the first coke ovens producing tar and
ammonia as by-products were constructed at Sulzbach, near
Saarbriicken, in 1766. These first attempts were very crude and
of little practical value. In 1781, Sir Archibald Cochrane, Count
of Dundonald, obtained a patent on the production of tar, volatile
oils, alkalies, acids, pitch, and coke, from bituminous coal. Very
slow progress was made in the saving of by-products ; their practical
manufacture and sale in market was not assured until about the
year 1883. The reason for this slow progress has been attributed
to two principal causes: the low price of these products in market,
on account of the supply from the gasworks, under the method
in use, until recently, of making illuminating gas from bituminous
coal; besides, the early efforts at the coke works were expensive
and unsatisfactory, both in quality of coke and value of by-products
secured.

In 1856, Knab, of the Department Allier, France, built a group
of retort coke ovens in which a double purpose is evident: the
saving of the by-products of tar and aqua ammonia, and the manu-
facture of illuminating gas. The gases freed from tar and ammonia

200

TREATISE ON COKE 201

were returned to the ovens and burned in the flues to reenforce
the heat for coking. These ovens are described as having narrow
vertical chambers, 23 feet long, 6 feet 6| inches high, and 3 feet
3J inches wide. They were also provided with bottom draft.

The principal difficulty in extending the use of these ovens, and
which has only recently been corrected, consisted in the neglect of
proportioning the several parts of the oven to the requirements of
the quality of the coals to be coked. With the advent of correct
dimensions in the retort coke ovens, to meet the wants of the vari-
ous qualities of coal, their increased use in the manufacture of
coke and saving of by-products has been largely extended.

Jones and Blackwell took out patents in 1861 to produce tar
and ammonia by converting coal into coke in kilns, but the experi-
ment failed.

In 1862, Simon and Carves, of France, made very valuable
improvements in the original plan of the Knab oven. They intro-
duced side horizontal flues, in addition to the bottom flues in the
Knab oven. The gases from this closed oven were drawn into
condensers and scrubbers by an exhaust engine, the tar and ammo-
nia separated, and the remaining gas returned to supplement the
oven heat. The construction of this Knab-Carves coke oven, with
important improvements, in 1873, to assure the better distribution
of heat, afforded a model for subsequent coke ovens, and this
model was soon appropriated by Albert Huessner, who is credited
with the practical introduction of a successful oven and apparatus
for securing by-products from the coke-oven gases. Huessner
built 100 ovens in 1881, establishing the by-product industry on a
sound basis in Germany.

The quality of the coke made in these ovens was regarded as
inferior, on account of the rapid exhaustion of the gases by suction,
and it required many years with considerable improvements in the
ovens to overcome the objection.

The G. Seibel coke oven was introduced in France in 1881.
It has horizontal flues in the middle of the walls of the coking
chambers, with gas reservoir after the Simon-Carves plan, and
was the first oven built without grates for saving by-products.
At one plant in France the surplus gas, after the extraction of
by-products, is used for illuminating purposes. The temperature
obtained in this oven is fully equal to the Otto-Hoffman oven with
its expensive regenerators.

The main element in the design of this oven is to maintain the
process of coking so successfully in use in the beehive ovens; that
is, the carbonization of the charge of coal in the oven, beginning at
the upper surface and going downwards to the bottom of the oven,
proportioning the heat as the coking progresses from top to floor
of oven. This secures the deposition of the maximum quantity
of carbon from the evolved hydrocarbon gas from the coal in
coking. About 11 per cent, of deposited carbon has been secured

202 TREATISE ON COKE

under this method in this coke oven, which not only glazes the
coke with nearly pure carbon, but also adds very materially to
the percentage of the carbon in the coke, reducing, relatively, the
ratio of impurities to the carbon in the coke.

The principles under which this oven was designed by Mr. G.
Seibel are undoubtedly correct, and should afford excellent results
in the quality of coke and saving of by-products.

About the time of the introduction of the Seibel oven, the
earnest attention of coke manufacturers was directed from previous
experience to the two prime requirements in the manufacture of
retort coke: the production of good coke, and the securing of the
by-products. The first consisted in the necessity of proportioning
the size of the oven chamber to meet the requirements of the
different qualities of coking coals, the coals rich in volatile matters
requiring treatment in wider ovens, while the dry coals or those
low in volatile matters demanded narrow ovens for the best products
in coke.

The previous inattention to these prime requirements, especially
in coking the continental coals of Germany, Belgium, and France,
caused the retort cokes to be regarded with suspicion as to their
adaptability for producing coke for metallurgical purposes. It
required considerable time to remove this prejudice. The ultimate
credit of doing so is attributed to Dr. C. Otto and Company, of
Dahlhausen on the Ruhr, who, in 1881, erected ten trial ovens,
which laid the foundation of a system coming later into favorable
use, But it required the addition of the Siemens regenerator, in
order to heat the air required for the complete combustion of gas
to as high a degree as possible, before a successful condition was
assured. This addition was patented by Gustave Hoffman in
1883, constituting the Otto-Hoffman coke oven.

Some criticism has been made questioning the value of the
addition of the Siemens regenerators to the Otto-Hoffman oven,
with the increased cost involved by these appendages. The
arrangement of vertical side flues is also regarded as objectionable,
from the difficulty of distributing the heat evenly, with the reduced
amount of it secured.

This Otto-Hoffman coke oven was further improved by E. Fest-
ner, of Gottesburg, who made an important change in the position
of the flues in the oven side walls, by using the horizontal in place
of the vertical position. He also abandoned the Siemens regener-
ator, replacing it with the Ponsard gas furnace. In establishing
these improvements, he is reported as having the cooperation of
Hoffman, and the oven has been named the Festner-Hoffman
coke oven.

The Semet-Solvay oven came into appreciative notice in 1887.
It is designed for coking dry coals or a mixture of pitchy and dry
coals. Its side walls are made with flued and jointed tiles in hori-
zontal position. This secures a maximum heat which can be

TREATISE ON COKE 203

evenly distributed so as to avoid the destruction of firebrick lining
by concentrated heat at certain localities. The dimensions of this
oven are made to meet the requirements of the several qualities
of coking coals or mixtures of such coals. It has two simple heat
reservoirs and avoids the rather expensive regenerators and recuper-
ators of some other ovens. It is usually regarded as a plain
economical oven, well adapted to the saving of by-products.

In Scotland, Mr. Henry Aitken, of Falkirk, introduced impor-
tant improvements in the method of coking in the beehive oven,
and subsequently added appliances for the saving of by-products
from the gases of this oven. The first improvement, of 1874, con-
sisted in the application of hot air into the dome of the oven, so as
to increase the heat by the thorough combustion of the gases
evolved from the coking coal beneath. This augmented heat supply
was designed to save the burning of the fixed carbon in the coking
coal. In 1880, he introduced apparatus for the saving of the
by-products in the beehive ovens. This consists in the placing of
a triple radial perforated conduit in the bottom of the oven, con-
nected with an exhaust pipe leading to condenser and scrubber to
secure the by-products. These inventions were quite successful
and approached at the time very nearly to the best results in
retort-oven practice.

In England, in 1883, Mr. John Jamison devised methods very
similar to Aitken 's for saving by-products in coking in beehive
ovens. He introduced no change in the form of the ordinary
beehive oven, except to place channels or conduits in its bottom,
through which to extract the gases of carbonization by a slight
suction exhaust. He has obtained in this way good results in both
coke and by-products.

Simon and Carve's introduced in England, about the year 1880,
the improved retort, recuperative coke oven, bearing their names.
This plan is a decided improvement on the Coppee model in sim-
plicity of design and efficiency in work, but the Coppee oven afforded
the base for the Otto-Hoffman and the Simon-Carves. It has hori-
zontal flues with attached apparatus for securing the by-products,
and this plan of oven has been quite successful in producing a
large percentage of good coke at a moderate cost.

In Great Britain, with its excellent coking coals, the continental
retort oven was slow in finding general favor. This condition
existed from the fact that the beehive oven produced excellent
coke for metallurgical purposes. The small wastage of carbon by
this method was not regarded as of prime importance, as it was
urged that the physical structure of the coke made in the beehive
oven under slight pressure developed a cell structure that conferred
superior calorific energy on this kind of coke. And it was further
submitted that the smaller product of the beehive oven, in blast-
furnace use, was ecjual to the work of the larger product of the
denser retort coke.

204 TREATISE ON COKE

Doubtless in the early efforts for the introduction of the retort
coke ovens the importance of proportioning their several parts for
the coking of coals of different qualities was not so well understood
as in more recent times. Besides, the value of the by-products
from the coke ovens was not considered in a manner commensurate
with its importance.

In the United States of America, with its great coal fields,
embracing so large areas of excellent coking coals, the introduction
of retort coke ovens has been slow. This arises mainly from the
large cost of these ovens, especially when supplied with an equip-
ment for saving by-products. A secondary hindrance consists in
the expensive labor cost in small experimental plants. A maximum
number of coke ovens is required to assure minimum cost in the
labor of coke making.

However, since the decline of the production of tar and ammo-
niacal liquor in the gasworks, the by-products from coke works
have realized a revival of their importance, especially the sulphate
of ammonia as a valuable farm manure, which, in the progress of
improved agricultural operations, is coming largely into demand.
These have given retort coke ovens renewed attention and
importance, and this will be further reenforced as the use of
coke enlarges, requiring the use of some of the secondary qualities
of coals to maintain the necessary supply of this valuable metal-
lurgical fuel.

As a sequence of the requirements of coke manufacture on the
continent of Europe, demanding for successful treatment the use
of the closed or retort coke ovens, the auxiliary apparatus for
saving the by-products was adjusted to these types of ovens, and
some ovens were designed with a view mainly for the securing of
the by-products. In Great Britain, with the satisfactory beehive-
coke-oven manufacture, the appliances for saving the by-products
had their first application on this plan of oven, graduating in recent
years to the retort type of coke ovens. In the European countries,
the use of sulphate of ammonia as a manure has received careful
attention, as this salt is an excellent fertilizing agent and is largely
used in farming operations. The tar affords elements that are
widely used in many of the industrial arts.

The large areas of superior coals for making coke found in the
United States and in Great Britain afford the best metallurgical
coke in the beehive oven. This condition, even with its expensive
labor and wraste of fixed carbon, restrained efforts in improve-
ments in the coke oven, except in the single direction of economy
in the labor of drawing the -coke from the oven by mechanical
appliances in place of manual labor, as noticed in the instance of
the Welsh coke oven.

But in Belgium the conditions are quite different. The coals
there are poor in quality and low in the elements that fuse the coal
in coking. In this busy little kingdom, with the expanding use of

TREATISE ON COKE

205

coke, it early became a very urgent requirement to devise ovens
to coke their inferior coking coals. The Belgian coke oven was the
result of efforts in this direction. It was followed by a number of
ovens of similar construction bearing its name.

NUMBER OF BY-PRODUCT COKE OVENS IN USE AND UNDER

CONSTRUCTION IN THE UNITED STATES AT THE

CLOSE OF YEAR 1902, BY STATES

State

Ovens,
December 31, 1902

State

Ovens,
December 31, 1902

Completed

Building

Completed

Building

Alabama

240

400
75
100
30

40
200

60
574

Ohio
Pennsylvania. . . .
Virginia ........
West Virginia. . .

Total

50
592
56
120

60
412

Maryland

Massachusetts

Michigan
New Jersey
New York .

1,663

1,346

TABLE EXHIBITING THE USE OF RETORT OR BY-PRODUCT COKE
OVENS IN THE UNITED STATES FROM 1893 TO 1902, INCLUSIVE

Ovens

Year

Product
Net Tons

Built

Building

1893

?.2

12,850

1894

16,500

1895

18,521

1896

160

120

83,038

1897

280

240

261,912

1898

520

500

294,445

1899

1,020

906,534

1900

1,085

1,096

1,075,727

1901

1,165

1,533

1,179,900

1902

1,663*

l,346t

1,403,588

*Includes 525 Semet-Solvay, 1,067 Otto-Hoffman, 15 Schniewind, and
56 Newton-Chambers.

•{•Includes 210 Semet-Solvay, 664 Otto-Hoffman, 412 Schniewind, and
60 Retort Coke Oven Company.

The Belgian oven was succeeded by a large variety of closed or
retort ovens in Germany, Belgium, France, and recently in England.
As we shall consider these ovens in their proper order, we will
endeavor to unfold the main designs of their authors in each plan
of oven. It may be submitted here that the chief and imperative
requirement in all of these ovens is the economy of heat in the
operation of coking. To satisfy this prime demand, passages and

206

TREATISE ON COKE

flues have been introduced in the bottoms and walls of the ovens
to utilize the heat of the gases expelled from the coal in coking,
returning it through these passages and flues to maintain the
necessary oven heat in coking.

During the past decade, auxiliary apparatus has been attached
to some of these ovens and has been successful in saving the chief
by-products of tar and sulphate of ammonia from the gases evolved
from the coal in coking. After these by-products have been
secured, the gases are returned to regenerators and used in the
usual way in heating the coke ovens. Any surplus heat from these
gases is frequently utilized under the boilers in making steam.

Belgian Oven. — The Belgian coke oven was evidently designed
to satisfy three principal requirements:

1. To meet the condition of coking coals of inferior quality,
requiring the economy of heat from the gases by returning them

(b)

FIG. 1. ORDINARY BELGIAN COKE OVEN

(a)J3ectipn through A A; (b) section through B B; (c) section through C C; (rf) section

of section through G G',
(/) plan of pusher track;

through D D; (e) end elevation; "(/) plan of top of ovens; (g) plan of section through G G;
through H H; (£) plan of section through / /;

(h) plan of section

(K) elevation of pusher track.

under and around the coking chamber of the oven, through passages
and flues, and to retain the oven heat by the rapid discharge of the
coke, cooling it outside the oven.

2. To economize the work of drawing or discharging the
coke from the oven by mechanical appliances in place of the

TREATISE ON COKE 207

rather slow and expensive methods of performing this work by
manual labor.

3. To exclude the air in coking the coal as much as practical,
so as to save the waste of fixed carbon usually made in ovens
admitting the admixture of air in the coking chamber, and in
affording an increased percentage of coke from the coal charged
into the oven.

The inferior dry coals of Continental Europe can only be coked
to best advantage in closed ovens. This involves, however, the
necessity of cooling the coke outside the oven, leaving in this coke
4 to 8 per cent, of moisture, under ordinary conditions. Whether
the increased product of coke from the coal charged in these
ovens will compensate for the augmented moisture in the coke,
from the necessity of watering it outside the oven, will be con-
sidered hereafter in detail. On the other side, by this rapid
discharge of coke, the oven's heat is retained and acts quickly
on the newly charged coal, utilizing the small volume of fusing
matters in the dry coals.

Fig. 1 shows the main features of the early Belgian coke oven ;
references to its parts are given on the drawing. Its general
design consisted in the economy of heat in coking the inferior
dry coals. The width and height of the oven chamber were
usually proportioned to meet the requirements of the coals to
be coked; the dryer the quality of the coal, the narrower the
chamber of the oven, and, conversely, the oven was made wider
when coals inheriting more hydrogenous matter were to be used in
coke making.

During the working of the bank of Belgian coke ovens, by the
Blair Iron and Coal Company, -at Hollidaysburg, Pennsylvania,
the coal used was from the Miller (B) seam in the Bennington
mine. It was composed as follows:

PER CENT.

Volatile matter 22 . 38

Fixed carbon 68 . 50

Ash 8 . 00

Sulphur 1 . 12

Total 100.00

The theoretic coke from the above coal, assuming 40 per cent,
of the sulphur to have been volatilized in coking, is 77.17 per cent.

The Belgian coke ovens, using this Miller coal, gave the follow-
ing results: coal charged, 6.86 gross tons; coke made, 4.81 gross
tons; difference, 2.05 gross tons.

In the large bank of Belgian ovens, formerly in use at the blast
furnaces of the Cambria Iron Company, at Johnstown, Pennsyl-
vania, and using the Miller seam coal, the yield of coke was
70.3 per cent., indicating a loss of fixed carbon of 30.02 per cent.
This coal was washed in preparing it for coking in these ovens.

208 TREATISE ON COKE

At the Bennington bank of one hundred beehive coke ovens,
using the Miller coal (B) , from the same mine and of similar quality
as formerly supplied to the Belgian ovens at Hollidaysburg, the
product gave an average yield of coke of 64 per cent., requiring
1.56 tons of coal to make 1 ton of coke. As previously shown, this
coal affords 77.17 per cent, of theoretic coke. The beehive ovens
yield 64 per cent, of coke, showing a loss of fixed carbon of 17.06 per
cent. Equating the relative conditions of moisture in the Belgian
oven, coke watered outside the oven, and the dryer coke of the
beehive oven, watered inside it, the increased yield of coke from
the Belgian oven over the beehive oven is about 10 per cent.

The modifications and additions to this family of coke ovens are
quite numerous; even a brief description of their various forms
would exceed the limits of this work. The main principles of the
original Belgian oven have been retained in its successors, though
not always bearing the family name.

The ovens selected for illustration and description will be taken
from the most practical types for the manufacture of coke at this
time, and also those specially designed for supplementary apparatus
in saving the by-products of dry distillation in the coking process.

Coppe'e Coke Oven. — This oven is also a Belgian invention and
was in use on the continent prior to 1861. In 1873 and 1874 it was
introduced in England, and has also been used in a few localities
in the United States. The main principles embraced in the design
of the Belgian coke oven are preserved in the plan of the Coppee
oven, but the latter is much more complex in its structure and
operation than the former. Fig. 2 shows its general design.

The Coppe'e coke ovens are usually built in blocks of twenty to
thirty ovens, and the plans and sections referred to in the following
description embrace a block of twenty-two ovens with draft chimney
and other appliances. View (a) represents a longitudinal section
passing through the middle of a side wall of an oven, on line C D of
the plan (e) ; (b) shows a longitudinal section through the middle of
an oven, on line A B of plan {e) ; (c) shows section passing through
the middle of an end side wall, on line E F of plan (e) ; (d) shows
cross-section and elevation, on line Y Z of plan (e) ; (e) is a plan
from the line G V of section (d) ; the courses of the gases are
shown by plain arrows, while the way of air-courses is shown by
crossed arrows.

The gas escapes from the oven through twenty-eight openings a
situated on both sides of the oven, into the horizontal flue b, where
it meets and mingles with the hot air brought by the flue c and
small flues d. The perfect combustion of the gases takes place in
the horizontal flues 6, b'. The inflamed gases descend through
twenty-eight vertical flues e into the flue / situated under the floor
of the odd-numbered oven; in this flue / the gases of the two side
walls, communicating with the flue under the floor, mix together.

TREATISE ON COKE

209

210 TREATISE ON COKE

The gases run from one end of the flue to the other in the flue /
and then pass into the flue /' situated under the floor of an even-
numbered oven; next, the gases go through the opening g, reach
the flue h' situated under the regenerating air flues, and ultimately
flow into the main flue i. This main 'flue takes the gases to the
boilers, or to the chimney, as the case may be.

In the flues / situated under the floor of the odd-numbered ovens,
an opening g is provided with a damper which regulates the admis-
sion of gases into the lower flues h and h' .

The requisite air for the combustion of gases is taken from the
outside by an opening / situated in the end buttress wall, then it
descends to reach the regenerating flues k, from one end of the
batch to the other end of it. These air flues are situated between
gas flues /, /', and h, h', The air that enters from the outside by
the opening / leaves the flues k through the opening /, having been
raised to a temperature of 600° to 800° F. This hot air ascends the
shaft / and reaches the flue c situated on top of ovens. Out of this
flue c the hot air is divided by .the small flues d, situated above
each side wall, into the flues 6, 6', also situated above the side walls
and immediately under the flues d.

The discharging of the ovens is made by a ram engine, which
pushes the coke, first out of the odd-numbered ovens, so that each
newly charged oven finds itself between two others in full operation ;
therefore, between two highly heated ovens. These alternate new
charges generate gases at once which escape on both sides through
twenty-eight openings, enter the flues b, b', mingling with the hot
gases of the adjoining ovens and the hot air supplied through the
flues d.

From the foregoing description of the operations of this oven,
it is evident that in using very dry coals the alternate charging
and discharging of the ovens is necessary to the diffusion and main-
tenance of the oven heat. With coals richer in volatile combustible
matters, the ovens could be drawn in sections, thus avoiding any
injurious pressure on the walls of the ovens by the swelling of the
coal in coking. These ovens are usually constructed of such width
and height as may be required in coking coals inheriting different
volumes of hydrogenous matters, varying in width from 15 inches
to 13 inches, with heights governed by the same elements in the
coal to be coked.

It is claimed that the Coppee oven affords 70 to 83 per cent, of
coke in Belgium, and 67 to 75 per cent, in England. A bank
of thirty Coppee coke ovens, formerly in use at the Conemaugh
furnace of the Cambria Iron Company, constructed with some modi-
fications from the foregoing plan, especially in the arrangements of
the crown flues, gave the following results in their work in coking
a moderately dry coal during the fiscal year 1886. The amount of
coal charged into the ovens during the year was 12,630 gross tons;
the coke produced, 8,680 tons, exhibiting a product of coke, weighed

212 TREATISE ON COKE

after having been watered outside the ovens, of 68.72 per cent.;

using 1 .22 tons of coal to make 1 ton of coke. The coal used was

constituted as follows:

PER CENT.

Moisture 212° F 560

Volatile matter 17 . 700

Fixed carbon 73. 980

Ash 7.360

Sulphur 820

Phosphorus 006

It may be noted that this coal is very low in its volatile combus-
tible elements, requiring the burning of some of the fixed carbon
of the coal to sustain the oven heat in coking. The leanness of
volatile hydrocarbons in the coals at the city of Johnstown is
quite remarkable and exceptional, as the Appalachian coals east
and west of this belt inherit normal volumes of these matters,
with their usual increase westwardly.

The work of the old Belgian coke ovens on the dry coals at
Johnstown, and the results at Hollidaysburg on the second quality
of coking coal from the Miller (B) seam at Bennington, have been
considered in a former section. The average result of a full year's
work of a bank of thirty Coppee coke ovens at the Conemaugh
furnace, supplied with the dry coal from the Lemon seam in the
Johnstown basin, has also been submitted. The use of all these
ovens was discontinued some years ago, for reasons that cannot
be wholly attributed to the work of the ovens.

The full comparison of the economies of the open and closed
ovens, with cost of construction and adaptability of plans for
special coals, will be considered hereafter.

Appolt Coke Oven. — A radical departure from its predecessors,
in its general plan, is the Appolt coke oven. It was evidently
designed to meet the general conditions covered by the Belgian
oven, with additional elements in the economy of the work of
coking, and was particularly adapted for coking dry coals, which
require a rapid exposure to a high temperature in the initial stage
of coking, to utilize the small ratio of fusing matters in such coals.

This oven, Fig. 3, is described as *" consisting essentially of a
series of upright rectangular retorts, the longer sides of the rectangle
being two or three times the length of the shorter. The retort is
wider at the bottom than at the top to facilitate the discharge of the
coke. These retorts are grouped in companies of twelve, eighteen, or
twenty-four, as the requirements may be; the whole enclosed in a
large rectangular brick chamber, which may be termed the combus-
tion chamber, the retorts being surrounded on all sides by air spaces,
these spaces being in communication, and the walls that form the
sides of the retorts connected together by solid blocks of firebrick.

*From Report of J. D. Weeks, Esq., to Census Office, 1885.

TREATISE ON COKE 213

"Between the firebrick walls of the combustion chamber and
an outside brick wall is a space filled loosely with some powdered
substance, as sand or other poor conductor of heat, which allows
a certain degree of expansion and contraction of the firebrick wall
of the combustion chamber within. This combustion chamber
for a group of twelve retorts would be about 17 feet long, by 11 feet
6 inches wide, and 13 feet high.

"Each retort is about 4 feet long and 1 foot 6 inches wide at
the base, and 3 feet 8 inches long and 13 inches wide at the upper
part, the walls being about 4f inches thick.

"The ovens are placed in two rows, back to back, the bottoms
being provided with cast-iron doors strengthened by transverse
bars of wrought iron. The partition walls of each chamber, at a
distance of from 16 inches to 2 feet from the base, are traversed
by two rows of small horizontal openings 5£ inches long and about
3^ inches high, nine on the wide side and three on the narrow side.
At the upper part there are three similar openings on the wide
side only.

"Through these openings the volatile products evolved during
the coking of the coal pass into the surrounding open spaces of the
combustion chamber, where they are burned by mixture with
atmospheric air admitted through holes in the wide sides of the
outer wall of the oven."

The designs of these ovens are very complete, especially on the
lines of rapid and economical work. The yields of coke as given
by the Messrs. Appolt are as follows: Each retort contains about
1| tons of coal. The coking is usually completed in 24 hours.
Belgian coking coal gave from 80 to 82 per cent, of coke, and
English coking coal 72 to 73 per cent. No analyses are given with
these" statements and we can learn little of the actual work of this
oven.

Theoretically, this is a very perfect oven, yet it has not come
into. as general use as some of its competitors. The two chief
elements in retarding its more general use consist: (1) in its large
original cost and in the expensive cost of repairs; (2) the great
height of the oven, 13 feet, compelling coking under much pressure
and producing in the middle and lower sections of oven coke of
objectionably dense physical structure. This dense product of
two-thirds of its coke must be injurious to its character, especially
in blast-furnace use.

It is probable that the adverse conclusion of Sir I. Lowthian
Bell, in 1871, regarding the value of Appolt and other flued-
oven cokes, was induced by the dense physical structure of
these cokes, as it is difficult to understand how their chem-
ical composition could invite criticism, for the reason that, in
the beehive and other open or non-flued ovens, some of the
fixed carbon of the coal is consumed in coking, reducing its
volume in the coke.

214 TREATISE ON COKE

Comparison of Oven Types. — It would exceed the limits of this
volume, at this time, to follow up, in order, the several types of
ovens from the ancient beehive to the modern retort oven, but it is
designed to submit the chief successful and practical types of these
ovens with their individual desirable elements.

It may be again noted here, that, in the progress of develop-
ment of the by-product industry, three special root types of ovens
have been used: (1) The beehive, into which air is moderately
admitted and its heat maintained by burning a portion of the fixed
carbon of the coal. Its by-products were moderate in quantity
as well as in value. Aitken, of Scotland, and Jamison, of England,
have successfully applied to this type of coke oven, appliances for
the saving of by-products of tar and ammonia. (2) The Belgian,
Coppee, and related ovens and improvements on the Knab, which
are closed or retort ovens with vertical flues. (3) The Simon-
Carves oven is a closed retort oven with horizontal flues and
recuperator.

These two types of closed ovens utilize the oven gases, after
having been deprived of by-products, by retaining them to heat
the chambers of the ovens, thus saving the burning of the fixed
carbon of the coal in coking. This utilization of the gases evolved
in coking, by returning them to supplement the oven heat, is the
distinctive characteristic of the family of retort coke ovens.

The positions of the coal in the chambers of these three typical
coke ovens have been clearly defined by the three postures in which
a common, brick can be placed. Laying it horizontally on its
broadest side shows the posture of the charge of coal in the beehive
oven; placing the brick vertically on its side illustrates the shape
in which the coal is coked in the Belgian ovens; and by placing the
brick vertically on its en<l, the posture of the charge of coal in the
Appolt oven is accurately represented.

It has been pointed out that the designs of the coke ovens
following the original beehive were chiefly made to satisfy the
three principal conditions of the manufacture of coke: (1) to
coke inferior coking coals; (2) to economize the work of coking,
by mechanical appliances; (3) to secure a large percentage of coke
from the coal charged into oven.

The relative ultimate economies of each system of coking will
hereafter be considered in detail, embracing capital invested in
construction of each type of oven plant, the percentage of coke
obtained, cost of making it, and the quality and value of the coke
produced.

With the expansion of the use of coke in metallurgical opera-
tions on the one side, and the gradual exhaustion of the areas of
the best coking coals on the other, it becomes evident that to meet
the coking requirements of the lower qualities of coking coals
special plans of coke ovens will be required to assure the best pos-
sible product of coke.

TREATISE ON COKE

215

Modifications of Appolt Coke Ovens at Blanzy. — We make the
subjoined extracts from a communication to the Societe de 1 'Indus-
trie Minerale, by M. Marie, engineer at the Blanzy collieries.
Several types of ovens have been employed at Blanzy, where
from 20,000 to 25,000 tons of coke are made each year, but of
different types only two remain, the horizontal Coppee and the
Appolt type.

"A few modifications have been introduced in the Appolt ovens
in order to utilize the waste heat for firing the boilers or to take
off the gas for other purposes. The Appolt oven generally consists
of eighteen vertical retorts, ar-
ranged in two rows in a large heat-
ing chamber. The gases issuing
from the retorts by narrow hori-
zontal apertures at the bottom
are ignited and permeate through
the heating chamber, air entering
by orifices at different levels.
The products of combustion
escape through eight passages at
the level of the lower part of the
retorts, communicating by hori-
zontal flues with vertical chimneys
at the four corners of the oven.
Eight other and smaller orifices at
the top of the heating chamber
may also serve to take off the
waste flames; but they are not
generally employed, as their use
leads to a cooling down of the
lower part of the oven. The out-
let passages, below the level of
the gas exits, must draw along a
portion of these gases before their
complete combustion, and with- ;;'"^
out their having contributed to
heating the oven; so that, in the
chimneys, and especially where the passage is throttled by dampers,
the temperature is very high, rendering maintenance costly and
difficult. Moreover, this arrangement gives but little facility for
graduating the temperatures, which are always too high in the
middle of the oven and too- low at the two ends, thus delaying
the operation of coking in the retorts at the corners, which cannot
be drawn every 24 hours.

"In order to improve this state of things, the direction of
the gases has been completely changed. The gases leave the retorts
by the narrow apertures a, a, Fig. 4, at the bottom, and air for
combustion enters by the passages b, c at different levels as

FlG'4-

MODIFICATIONS OF APPOLT COKE
OVENS AT BLANZY

216 TREATISE ON COKE

before; but the products of combustion are entirely evacuated
at the upper portion of the heating chamber, and the gases,
before arriving there, are obliged to follow a course d, e, f that
forces the gas and air to mingle and enter into combustion, thus
heating as evenly as possible all the parts of the oven, while
apertures with dampers are provided in the partitions for still
better regulating the temperature.

"In the long sides of the oven there are as many evacuation
apertures g as there are retorts ; and, besides, at each end there are
four apertures in the shorter sides, so as to heat the corner com-
partments, which, since this modification, coke as rapidly as the
others. Each of these apertures is fitted with a damper, which
permits of regulating at will the temperature of coking; and they
communicate with a descending chimney i, traversing the whole
height of the oven, and then enter the horizontal collector /, divided
in the middle by a vertical partition into two equal parts.

"Owing to this arrangement, the heating chamber is itself
surrounded by all these chimneys i, which heat it still further and
protect it from external cooling, while the chimneys themselves
are separated from the outer masonry by an air space, which also
protects them. From the collector /, the gases pass into another
flue k by means of four apertures fitted with dampers, and, when
they reach this flue, the gases may be sent at will under the boilers
and thence up their chimneys, or directly, on the other side, up
other chimneys, dampers serving to direct the gases to one or
other end, according to requirements.

"This double direction was rendered necessary by the inter-
mittent working of the boilers, which are only in use by day, while
it also permits of a complete stoppage, so far as the boilers are
concerned, for cleaning and repairing them. The object of the
collector / is to regulate the draft in the descending chimneys it
which, without such an arrangement, would always have too strong
a draft on the side where the gases were directed. Lastly, the oven
may be completely closed by the dampers on Sundays and holidays,
when the ovens are not drawn.

"The flues / and k and descending chimneys i are, for a con-
siderable distance, surrounded by air, which is raised to a tolerably
high temperature; and this heated air may, if required, be used
for the combustion of the gases in the heating chamber by suitably
regulating the dampers. It was, however, necessary to discon-
tinue the use of this hot air until the excess of gas produced by the
oven was taken off, as the temperature which it produced was too
high and might damage the bricks of the oven.

"The boilers are vertical and provided below with a series of
Mac-Nicol tubes, which greatly increase their evaporating power.
They supply steam for driving the lifts, the coke breakers, and a
washing apparatus. On Mondays, when there is no gas in the
ovens, it becomes necessary to heat them so as to have steam

TREATISE ON COKE 217

enough to begin work; and for this purpose they are provided
with grates, so that they may be fired like ordinary boilers.

"The first two Appolt furnaces constructed by the Blanzy Com-
pany in 1862 were built, as usual, of burnt bricks, which it was
necessary to cut and square carefully; but, noticing the difficulty
caused and length of time required by this work, the late M. Jules
Chagot, who then managed the Blanzy Colliery, conceived the idea
of building the ovens with unburnt bricks, as practiced in the
furnaces of glass works. Accordingly, since 1866, all the ovens
have been constructed in this manner, except one, in which case
there was no time to wait for trie bricks. One consequence of the
use of unburnt bricks is that they must be made on the spot, as
they cannot be transported easily.

"This system possesses the following advantages: (1) facility
for squaring the bricks, which is done with a scraper instead of by
hammer and chisel, thus economizing about one-sixth of the labor;
(2) the faculty of the unburnt bricks to adhere together, so as to
make of each retort a monolith, the joints of which cannot be
detected ; (3) saving of the burning, which is effected when firing
up the oven, which must always be heated very slowly, whatever
be the method of construction.

" In addition to the above, the manufacture of the bricks on the
spot has the advantage of leaving no doubt as to their quality and
composition, or the manner in which they may be expected to
behave in the fire, and it also permits of varying the composition
according to the position occupied by an individual brick, of using
very large bricks and of thus diminishing the number required.
In the ovens built at Blanzy, the bricks are at least 25 centimeters
(10 inches) high; each course of a compartment is built of six
bricks; four courses of the upper portion are made, each in a single
piece, and each course of the descending chimneys, also in a single
piece, so that it may be laid very rapidly. In cases where the
bricks are not required to adhere, in order to prevent displacement,
a piece of wood or cardboard is introduced into the joint during
construction and this packing piece is consumed when firing up.
Actual experiment has shown the amount of clearance that must
be left, which is greater in proportion to the quantity of quartz
entering into the composition of the brick.

"Before charging the oven it must be fired up with great pre-
caution for at least 3 weeks ; and it is necessary to keep a watch on
the expansion, and unscrew the" nuts of the tie-rods as required.
All the nuts must be provided with lead washers, the squeezing
out of which gives warning of the moment when they must be
slacked. Thanks to all these precautions, it was found possible to
construct the last oven with twenty-two compartments instead of
eighteen, without the slightest fracture being perceptible in the
retort. There is an advantage in getting as many compartments
as possible in the same bank, because the cost of the two heads of

218 TREATISE ON COKE

the chimneys and of the boilers is spread over a larger number of
retorts, and therefore over a greater production of coke.

"On noticing what happens in the retorts after charging, it will
be seen that, during the greater portion of the carbonization, the
gas attains considerable pressure inside, and has a tendency to
escape, not only by the narrow apertures intended for this purpose
at the bottom of the retort, but also at the upper and lower joints
if they are not made well. If, therefore, during this period, the
gas be put in communication with a gasometer, the pressure of
which is regulated very low, the gasometer will be filled without
air entering the retort. As, in the present instance, the gasometer of
the gasworks is 250 meters (273 yards) from the oven, an exhauster
will be added for drawing off the gas from the retort, while leaving
behind it sufficient pressure to prevent the possibility of a vacuum
being formed in the retort. It will be possible, with practice, to
determine the time during which communication must be main-
tained, and at the end of this period a valve must be closed, allowing
the gas to escape by the apertures a, a, Fig. 4, for taking off the
gases. The gas will be taken off by the pipes /, the valves h,
and the general pipes m, in communication with the exhauster.
If, later on, it be found advisable to take off all the gas for recover-
ing the tar and the ammoniacal liquor, the apertures a will be
closed, and a second valve n and pipe o will be added for collect-
ing the gas not intended for lighting. After their tar and ammoni-
acal liquor are condensed, they will be sent into the flues b, c,
where they will burn with the hot air, serving to maintain the
heat of the ovens. The flues 6 and c are, in fact, already arranged
for receiving the gas pipes.

"With Appolt ovens, more labor is required than in any others.
For 17 or 18 hectoliters (mean 62 cubic feet) of coal charged,
2 hectoliters (7 cubic feet) of coke dust must be charged in for
closing the apertures at top and bottom, and also at least half that
quantity of small coke for protecting the gas exits a a and pre-
venting them from being obstructed by the coal. When the coke
is drawn, this dust and small coke must again be withdrawn from
the batch, which is a double work, increasing the volumes to be
handled by three-eighteenths on charging, and the same on
drawing, making one-third together. Hitherto the drawn coke,
received in a tram, has been quenched and tipped on a floor,
where the separation, screening, and loading up were effected
by hand.

"To lessen these expenses, the company put up a mechanical
screen. Trams of the drawn and quenched coke are brought by
an endless chain in front of a pit into which the coke is tipped,
and then raised by a Jacob's ladder to the top of the shed, whence
it falls into a screen, with bars 5 centimeters (2 inches) apart, which
keeps back the large coke. The latter falls into a hopper, where
it is stored, and whence it may be charged directly into wagons

-j

i 1 — |

— p

I 1 ° P

nil

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An n n nln r? r? rin n r? rrSrffi] 17 n IL n n

i r I

n — r

-jcj

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(14090;

202'^

17303— vi

FIG. 7. SEIBEL SYSTEM. PLANT FOR CONDENSING AND COLLECTING

a, Expansion regulating tank; b, condenser or refrigerating.

T7JT? n rr nlrnft? n TT n nln

[!i.l!!lliil!lli1li!lllii II

tooucTS FROM A DOUBLE BATTERY OF TWENTY-FOUR COKE OVENS
1 ; c, pipe; d, e, scrubbers; f, tar condensers; g, exhauster

TREATISE ON COKE 219

running on rails by a sliding door at the bottom, the overplus being
directed into a trommel or revolving drum, which divides it into
four sizes, from dust to 40 millimeters (1-& inches).

"As the quantities of small coke produced are not sufficient for
the demand, part of the large coke, instead of falling into the load-
ing hopper, will be sent to a breaker and divided by a similar
trommel into the same classes as those referred to above. It is
expected that this arrangement will permit of reducing by more
than half the labor required. The dust and the small coke required
for charging into the retorts with the coal will be led to hoppers at
the side of the ovens, whence they will be taken by the charging
trams.

"The coal used for coking is of the long-flame bituminous
variety containing: carbon, 77.82 per cent.; hydrogen, 5.2;
oxygen, 9.17; and nitrogen, 1.31; with an average of 6.5 per cent,
of ash, yielding in the crucible a mean of 63.71 per cent, of coke,
which is adhesive and rather soft, its structure showing long
bright needles.

"For some usages a harder coke is made from a mixture of
bituminous and anthracitous coal. The latter, obtained from the
west of the concession, contains: carbon, 82.48 per cent.; hydro-
gen, 3.88; oxygen and nitrogen, 6.14; with a mean content of
7.5 per cent, of ash, yielding in the crucible 83.5 per cent, of pul-
verulent coke, but the mixture of this coal with the bituminous
produces a large and dense coke, in which the above-named needles
are absent."

It is quite probable that this type of coke oven will be found
to be well adapted for the successful coking of the western coals,
rich in bituminous matter. The dimensions of the coking chambers
will require enlargement for the best results from these coals.

Simon-Carves Oven. — About the middle of the 18th century,
efforts were made in France and England to extract the by-products
of tar and ammonia from the gases evolved in coking coal. This
was stimulated at that time by the increasing use of coke in the
presence of a declining supply of charcoal. These efforts were
made prior to the practical introduction of works for making
illuminating gas from coal.

It is on record that Bolton and Watts first erected private
gasworks in 1798; this was followed by the construction of public
gasworks in London in 1813, Paris in 1815, and in Berlin in 1826.
The by-products of tar and ammonia, at these early gasworks,
were regarded as very undesirable resultants, which required
removal in purifying the illuminating gas, as at this time no useful
place appeared for them in the industrial arts.

A limited application was provided for the use of tar in Ger-
many in 1846, in the manufacture of roofing felt. In England,
tar was used in a small way, in 1838, for the preservation of timbers.

220 TREATISE ON COKE

This was followed by the utilization of the sulphate of ammonia
as a fertilizer, thus affording additional revenue to the gas makers
and coke manufacturers.

A long interval of slow progress followed the early production
of these by-products in the coke-making industry. This arose, in
part, from the feeling entertained at this period that ovens making
by-products could only produce an inferior quality of coke. Doubt-
less this judgment was induced by the poor quality of gas-house
coke for metallurgical purposes, and by the fact that coke for
blast-furnace use could only be made in beehive or similar types
of coke ovens, untrammeled by the cumbersome apparatus for
saving these by-products.

The foundation of ultimate success in making a good quality
of coke and at the same time securing the by-products was
laid in France by Knab's retort coke oven in 1856; but the
condensation of tar and ammonia from the gases from these
ovens was only practically successful by the Haupart and Carves
oven about the year 1881. This success imparted to the saving
of by-products renewed interest and gave the coke-making
industry additional value in France, Germany, and England.
The most important improvement in the Carves oven, from
the Knab, consists in the addition of side flues. The Knab oven
had only bottom flues.

Mr. H. Simon, in England, improved the Carves oven very
materially by adding recuperating flues in front of the ovens.
This recuperator affords ample heat in the process of coking and
overcomes the necessity of using a portion of the fixed carbon of
the coal for supplemental heat in coking.

The Simon-Carve's retort coke oven is a closed oven with hori-
zontal flues and apparatus for saving by-products. Its introduc-
tion was followed by 'a large number of retort coke ovens with and
without appliances for securing by-products.

The Simon-Carves coke ovens, Fig. 5, are constructed to pro-
duce coke suitable for all industrial purposes, with an economy of
coal, and at the same time to collect all the by-products in the
distillation of coal. These by-products serve for the manufacture
of ammonia and ammonia compounds, tar and all its derivatives,
benzol, carbolic acid, anthracene, coloring matter, etc.

In the Simon-Carves oven, the carbonization takes place in a
closed retort, and there is neither introduction of air nor combus-
tion in the interior of the oven. To convert the coal into coke,
the heat is applied externally through flues passing under the
floor and along the sides of the ovens. The heat is generated
from the gases obtained in the ovens from the coal, but only after
these gases have been deprived of every particle utilizable as a
by-product. Hot air is employed to render the combustion more
effective, waste heat from the ovens being utilized to heat the air.
Fig. 5 illustrates the main operations of this oven.

TREATISE ON COKE

221

The coal to be coked is conveyed to the top of the ovens by
the coal larry o ; by opening the doors of these larries, the coal falls
into the oven through the ports a. These openings and the doors
b and c at each end of oven are then tightly closed and luted, so as
to prevent the admission of air. The valve d is then opened,

(d)

FIG. 5. THE SIMON-CARVJ&S COKE OVEN

o, o', charging larries; a, a, charging ports to ovens; b, c, doors to each end of ovens;
*', pipe and tuyeres for transmitting gases; m, flues under ovens for gases and heated air;
j, nozzle to mix gases with air in flues m; g, h, g\, hi, g2, recuperator for smoke and waste heat
from flues n\ h, h\, flues to allow the gaseous products to escape to chimney; g, gi, g%, flues for
passage of air, which is heated on its way by contact with the hot walls of the flues h, hi;
e, opening on top of oven to collect the gases; d, valve to regulate the gases; /, coke wharf
where the coke is cooled.

putting the interior of the ovens in communication with the
exhauster pipe e. This conveys the gases evolved from the coking
coal to the condensers and scrubbers, where they are deprived of
the by-products and returned to be burned with hot air in the
oven flues. When the carbonization is completed, the doors of
the ovens are opened and the coke pushed on the platform or

TREATISE ON COKE

wharf / by a steam ram. The cooling of the coke is done on this
wharf. The interior dimensions of this oven are as follows:
length, 23 feet; width, 18 to 20 inches; height, 6 feet 6 inches.

The recuperator is an important and later element in this oven ;
it is described as follows: Externally to the brickwork of the
ovens are provided five longitudinal flues g, h, glt hlt g2; two of
these flues, h and hv allow the gaseous products of combustion to
escape to the chimney, the other three flues, g, gv g2, contiguous to
the former ones, serve as passages for the air, which is heated on
its way by contact with the walls of the flues h and hv The flues
h and hl communicate respectively with the chimney and the steam
boilers, which can be placed at each^end of the row of ovens, to
further utilize the waste heat of the products of combustion.

The charge of coal for each oven is 5£ net tons. The coking
requires about 48 hours with the usual quality of coals. With
coal affording 75 per cent, of coke, the production of an oven is
2.1 to 2.2 tons of coke per day, and about 10 per cent, of ammo-
niacal water and 3 per cent, of tar.

A battery of fifty ovens at Bearspark Colliery, England, makes
about 900 net tons of coke per week from coal constituted as
follows :

PER CENT.

Moisture 84

Volatile matter 26.85

Fixed carbon 68 . 44

Ash 3.10

Sulphur 77

Total 100.00

The theoretic coke from the above coal is 72 per cent. The
charge into the oven is 5^ net tons of coal, yielding about 4J tons
of coke in 48 hours. Deducting for ashes and breeze, the product
of marketable coke is practically 75 per cent. This shows a small
accretion from the deposit of carbon in the process of coking,
about 4 per cent.

The cost of labor in coking and collecting by-products is esti-
mated at 48 cents per net ton of coke made in a battery of fifty
ovens, producing together 105 tons of coke per 24 hours. The
annual product of fifty ovens of marketable coke would be about
34,000 net tons. The value of the by-products of tar and ammo-
nia is estimated at 68 cents per net ton of coke made.

The cost of a plant of fifty Simon-Carves ovens with appliances
for saving the by-products would be about as follows in the
United States, depending somewhat on locality:

Fifty ovens at $1,300 each $ 65,000.00

By-products appliances, tracks, houses, elevators,

etc 50,000.00

Total/ $115,000.00

TREATISE ON COKE 223

This estimate does not embrace a coal-washing plant. If such
is required, an additional sum must be added to the above, depend-
ing on the character of the coal and the impurities to be removed.

With coals inheriting 26 per cent, of volatile matter the saving
of by-products becomes more assured, but with the large expense
of the apparatus for saving by-products in the original cost of the
coking plant, and in its continuous and expensive operation and
maintenance, it becomes a matter demanding careful investigation
whether at this time it is an auxiliary that will surely afford to
the coke manufacturer an income that will compensate for invest-
ments in this addition to the plant, and afford a return to cover
the additional labor and repairs of apparatus. A thorough test of
the coal, for its value in affording by-products, should be made
as a prime element in the investigation of this matter.

These Simon-Carves ovens can be used in the manufacture of
coke, with or without appliances for the saving of the by-products
of tar and ammonia. Their system of horizontal flues is com-
mended for efficiency and economy of repairs.

G. Seibel's Retort Coke Oven.— By-Product Oven.— The Seibel
retort coke oven was patented by its inventor, Georges Seibel, in
France, in 1881, in England, in 1882, and in the United States of
America, in 1883. Two main principles appear to have been kept
in view by Mr. Seibel in the planning of this oven. (1) To preserve
the mode of carbonization that secures a maximum deposit of
carbon from the hydrocarbon gases in their ascent through the
upper incandescent coking portion of the charge. (2) To arrange
tuyeres and horizontal flues for the utmost economy in maintain-
ing oven heat by combustion of the returned gases, deprived of
the by-products, without the use of grates or complicated regen-
erators. The details of this oven are all in harmony with these
principles, exhibiting practical skill in the design of the retort coke
oven and its by-product-saving appliances.

Through the courtesy of Mr. W. M. Stein, of Primos, Pennsyl-
vania, I am enabled to submit the considerations that guided Mr.
Seibel, the inventor, in designing this oven, from his own notes,
with a description of the oven and its mode of operation.

"Until recent years, the method of coking in hermetically
closed ovens, permitting the saving of tar and ammonia, was not
considered a good one by the best engineers. It was generally
believed that, at best, only coke of inferior quality could be
obtained, hardly comparable with that of gasworks.

"For a long time, the coke ovens of the works of Marais, near
St. Etienne, Loire, modified according to the Knab system, failed
to find imitation. Today this method of carbonization with
saving of by-products is more appreciated, its advantages recog-
nized, and the prejudice entertained against the process is given
up, especially in Europe.

224 TREATISE ON COKE

"Experience has demonstrated that the coke thus obtained is
not inferior in quality to that obtained from the same coal in ovens
of the other systems. Germany has adopted ovens heated with
regenerated gas for saving of tar and manufacturing sulphate of
ammonia.

"The engineers today study and apply the different systems.
Belgium has ovens heated with gas and arranged to gather tar
and aqua ammonia, producing at the same time perfect coke,
suitable for all metallurgical purposes.

"In France, on the contrary, this question seems to have
remained indifferent to the interested parties. One large iron
company only, the company of Terrenoir Savoutte and Besseges,
had adopted the ovens of the system Carves and Company, in
1867. In three intervals, in 1867, 1873, and 1875, this company
has built at Besseges, eighty-five ovens of this type, being per-
fectly satisfied with the results. A group of these ovens is also in
operation for the past few years at Terrenoir.

"Such is the condition of carbonization with saving of by-
products in the principal coal centers of Europe.

"It may be said, however, that, though this question met with
little interest in France, it is beyond dispute that the improvement
originated in this country. In this direction, the Company of the
Mines of Campagnac located at Crausac, Aveyron, has been quite suc-
cessful, effecting a remarkable improvement in the coking industry.
In 1878 and 1879, this company built a first battery of nine ovens,
modifying the previously adopted method of carbonization. The
result obtained surpassed all expectation. In 1882, the company
added ten ovens to its first battery, which have given the same
satisfaction as the first. The mere enumeration of these results
will be amply sufficient to emphasize the progress accomplished.

"The coal of the Company of the Mines of Campagnac gives
theoretically an average yield of 64 per cent, of coke, ashes inclu-
ded, and 36 per cent, of volatile matter. The actual yield of these
ovens (Seibel) proved to be 75 per cent. The results obtained
during the whole year 1883 were, as above noted, 75 per cent.,
that is, 11 per cent, in excess of the theoretical yield.

"The production of tar was 54 pounds per each gross ton of
coal charged. From these results the following figures exhibit
the working of these ovens during the year 1883: coal charged
into ovens, 14,675 gross tons; production of coke, 11,006^ gross
tons; saving of tar, 360f gross tons.

"The Company of Campagnac commenced to save the aqua
ammonia and manufacture sulphate of ammonia only after the
beginning of the year 1883. The yield of sulphate of ammonia is
11 pounds for each gross ton of coal charged. The company then
increased the surface of the -condensing apparatus of the gases.
The tar production showed the effect immediately, increasing to
66 pounds for each gross ton of coal charged.

TREATISE ON COKE 225

"It follows from these figures that a coke oven of this system,
using this or a similar quality of coal, will produce yearly as fol-
lows: 648.81 net tons of coke, 25.99 net tons of tar, and 4.325
net tons of sulphate of ammonia.

"These results require no comment, I shall therefore not dwell
upon them, but complete the information by adding that the coke
made from this coal is superior in quality to that obtained from
similar coal in either the Appolt or Coppee ovens.

"We have during several months made coke regularly with
our coal in those two types of ovens and ours, and could therefore
determine the difference in the products, which was very easily
perceptible.

' ' The coke obtained from our ovens is harder and denser than
that obtained in the ovens named above. This improvement is the
consequence of the increase of yield, which surpasses the theoret-
ical yield by 11 per cent. This increase is obtained at the expense
of the carbon of the hydrocarbons of the gases, which, dissociating,
deposit part of their carbon in the pores of the coke. In short,
there is, during the period of distillation, a dissociation of the gases,
whereby a part of their carbon, being now in elementary form,
unites itself with the coke or fixed carbon, enriching it and increas-
ing its quantity and quality.

"Before describing the ovens, I will sum up the reasons which
have been guiding me in their construction.

' ' It has been proved long ago that the hydrocarbon gases pro-
duced by the distillation of the coal give up, under certain favor-
able conditions, a larger or smaller proportion of their combined
carbon. The formation of graphite in the retorts of gasworks is
due to this cause. On the other hand, if one compares carefully
the coke produced in a beehive oven with the coke from the same
coal produced in ovens of the other types, it will be recognized that
the coke from the beehive ovens is denser, harder, and in thicker
pieces than that produced by ovens of other systems. The differ-
ence is especially marked in coke from coals rich in volatile matter
like those of the basin Decazeville and Aubin. This difference in
quality was formerly so well known in the basin of Decazeville
that the foundry owners would take only beehive coke for smelting
in cupolas, excluding coke from the ovens Semet, Appolt, and
Coppee, which was formerly used simultaneously with beehive coke
in these works. The difference in quality can only be due to the
manner of carbonization. In the beehive ovens formerly used,
the process of coking commences at the top and then goes down-
wards. Now, if a charge of coal is put in a heated beehive oven,
all parts of the oven with which the coal comes in contact, walls
and bottom, cool immediately, the dome only retaining its heat.
The latter radiates heat over the charge and starts the distillation
there. This distillation continues downwards in the mass of coal,
and the gases produced in the lower portions are forced to traverse

226 TREATISE ON COKE

a porous mass during the formation of coke, in order to escape
through the only opening in the roof. The hydrocarbon gases
traversing in the early stage of the coking process through a
spongy mass are consequently surrounded by conditions very favor-
able to their dissociation, and give up to the upper regions of
the charge a certain proportion of their carbon. This fact can be
proved by a careful examination of a coke needle. These needles
are formed vertically in the beehive ovens ; at the lower part of the
needle, where it touches the bottom of the oven, the grain of the
coke is porous, puffed up, coarse; while it gradually becomes finer
and denser, approaching the top of the needle. The only possible
explanation of this difference in the condition of the same needle
is the one given above; it gives, therefore, a valuable hint as
to the dimensions and particular arrangement that must be
observed in designing the oven. In spite of the quality of the
coke produced in the beehive ovens in the basin of Decazeville
and Aubin, they have been abandoned. They yielded too small
a quantity of coke.

"Assisted by the observations just related and information
gained in the position of managing engineer at the mines of Decaze-
ville, I had, when called upon to construct coke ovens for the Com-
pany of the Mines of Campagnac, already studied up a type of
oven reproducing the method of carbonization in use in the beehive
oven, that is, where carbonization commences at the top and
extends downwards, but avoiding the losses that are incurred by
combustion of the fixed carbon.

' ' The retort coke ovens of the Company of the Mines of Cam-
pagnac carbonize from the top downwards and are hermetically
sealed.

"The following very simple arrangement was adopted. As
mentioned above, the Company of the Mines of Campagnac possesses
a group of nineteen ovens constructed in two batteries. The first
experimental battery of nine ovens and, in addition to these, ten
others have been built, the south end of the first battery being the
north end of the second. Each retort oven is a long, narrow,
arched chamber, 19 feet 8J inches long, 6 feet 6} inches high, and
27^ inches wide between the side walls.

"The dimensions of a more modern oven are given in Fig. 6.
The walls separating each oven from its neighboring one are 15}
inches thick and are built of first-class firebrick. The walls between
the ovens contain three horizontal flues, connected with each other
at their ends, so as to form a continuous flue, as indicated by a, b, c,
which is continued in d, under the sole of the oven, and finally
leads through the flue e into the main gas flue f. The latter takes
the gases to the chimneys, built at the ends of the battery of ovens.
The upper flue a has an opening at g, going through the wall to
the outside of the oven in which the gas burner is placed and
which will be described further on.

TREATISE ON COKE

227

228 TREATISE ON COKE

"In the middle of the retort of each oven, there is in the arch
an opening h that allows the gases of distillation to escape. To the
right and left are placed symmetrically the two other openings
i and / for charging the coal.

"The ovens are closed at their ends by cast-iron doors. Two
swinging doors are placed over these. The doors, as well as the
charging ports, are hermetically sealed by a clay point. Above the
opening h, which allows the gases of distillation to escape, a ver-
tical cast-iron pipe k is placed, which, by a branch k, connects with
a small barrel /, the opening of which can be closed by a valve m.
It is only necessary to lift the latter by its handle to effect the
stoppage. The gases of the distillation escape by means of the
pipes k and k into the hydraulic main, common to each battery.

"The hydraulic main is connected with a collecting pipe n, by
a vertical pipe o, which is also provided with a valve. Each battery
has its hydraulic main connected with the collecting pipe n, which
leads the gases of all the ovens to the condensing apparatus. An
exhauster worked by steam, which absorbs these gases, forces them
to traverse the various apparatuses with gradually decreasing pres-
sure. The gas gives up its tar and ammoniacal water, and is then
returned to heat the ovens.

"The purified gas is driven back by the exhauster to the pipe p
which extends along the top of the ovens. From this pipe, the
gases are distributed equally to the tuyeres by secondary pipes q,
which take to the burners the quantity of gas necessary for each.
The pipes q are supplied with valves that regulate or stop the flow
of gas to the burners. These burners consist of two tubes, one
within the other, and closed at the outer end by a flange. The
inner one is a little smaller than the outer one, so as to have a
circular space of .039 inch. Thus joined with the flanges put
together, and the outer tube connected with the feeding pipe by a
special small tube, it will be seen that the arriving gas flows in
the upper part of the circular aperture between the tubes in the
form of an elongated crown. The air necessary for this crown of
gas reaches the circular aperture by means of openings in the
inner tube. The supply of air can be regulated by shutting these
openings more or less.

"These are the general arrangements of the oven; it will now
be easy to understand its operation.

"When an oven is charged and cut off from the battery by
closing the valve m in the small barrel /, it is then recharged with
coal through the openings i, /, by means of the larries r, r. The
charge of coal is piled up as high as possible in the oven, nearly to
the spring of the arch, and is then leveled from both sides through
the upper opening of the doors, which remain open while the coal
is charged. This being done, the charging ports i, j are closed
by lids and the upper openings of the doors shut, both being her-
metically sealed with clay.

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17303— vi

FIG. 7. SEIBEL SYSTEM. PLANT FOR CONDENSING AND COLLECTING
a, Expansion regulating tank; b, condenser or refrigeratin.

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ushing Machine ^><;' t$!

P IODUCTS FROM A DOUBLE BATTERY OF TWENTY-FOUR COKE OVENS
; c, pipe; cf, ^, scrubbers; /, tar condensers; g, exhauster

TREATISE ON COKE 229

"At the same time, the valve m of the barrel / is opened and
the communication of the oven with the hydraulic main restored.
The carbonization now proceeds regularly, the gases of distillation
escaping under a small pressure through the opening h, and, by.
means of the pipe k, k, to the hydraulic main, from whence they
go to the condensing apparatus.

"The coal charged being wet, the walls and floor of the oven in
contact with it are considerably cooled. The arch is the only part
of the oven remaining hot.

"On the other hand, the two burners have continued heating
the wall flues a, which, in their function as combustion chambers
of the gases, have a higher temperature than the flues b, c. It is,
therefore, easily understood that the upper part of the charge will
receive from the flues a, as well as from the hot arches by radiation,
the greatest amount of heat.

"The distillation begins therefore very actively at the top of
the charge and progresses downwards. It will be seen from this
that the carbonization begins at the top and goes downwards,
exactly as in the beehive ovens. The gases generated in the lower
part of the charge must, in order to escape through the only
opening h in the oven, traverse the upper regions, which are ready
settled and have been brought to a high temperature. This shifting
of the gases causes them to give up part of their combined carbon,
which settles in the pores of the coke already formed and in the
fissures between the coke needles.

"I have endeavored to give the ovens such dimensions as are
most likely to facilitate the dissociation of the hydrocarbon gases,
which is such an essential part in the method of carbonization
just described.

"The general arrangement of the condensing apparatus at the
mines of Campagnac is shown in Fig. 7, which gives, at the same
time, their connection with coke ovens. At each end of the oven bat-
teries, a boiler is heated with the products of combustion resulting
from the heating gases, which must pass under the boiler on their
way to the chimney. These boilers work alternately, just as one or
the other chimney takes the products of combustion. Should it,
however, be found necessary, both boilers and chimneys can be used.

"The by-product-saving apparatuses are as follows: Fig. 7,
a, expansion regulating tank; 6, condenser; c, pipe condenser;
d, e, scrubbers; /, tar condenser; g, exhauster.

"These apparatuses work in the manner explained below.

" (a) This expansion regulating tank is a simple cylinder of
sheet iron, 4 feet 3 inches in diameter and 16 feet 5 inches high,
standing vertically. The gases of distillation arrive at the upper
part, through the collecting pipe n, Fig. 7, and leave the cylinder
at the lower part. Arriving at this large tank, from the tube n, the
gas expands, and this is sufficient to cause it to abandon a certain
proportion of tar and ammoniacal water. The temperature of the

230 TREATISE ON COKE

gas in this reservoir varies with the external temperature and the
amount of gas produced by the ovens; it is between 70° and 90°
centigrade (158° to 194° F.). The pressure on the contrary remains
constant and is 0.

" (6) From the expansion tank the gas goes to the square
condenser — a rectangular tank, 6£ feet high, 3 feet 4 inches wide,
and 3 feet deep. This tank is placed in another, open at the top,
of 1 foot high, 4 feet wide, and 3 feet 7 inches deep, filled with water
to the height of an overflow, which permits the discharge of the
condensed liquids. The first tank is divided into six compartments
by vertical hollow partitions, in which cold water circulates.
These partitions are so arranged that the gas, in order to circulate,
must pass from one compartment to the other and bubble through
the condensation water. Traversing this apparatus the tempera-
ture of the gases falls about 11° to 13° centigrade (52° to 55.4° F.),
and they lose a considerable quantity of tar and ammoniacal
water, the cooling surface of the tank being 258 square feet.
Leaving the apparatus, the gases have attained a depression of
.08 to .18 meter (3J to 7 inches) of water.

" (c) From the square condenser the gas passes through the
pipe condenser — a series of wrought -iron serpentine pipes, water-
cooled from the top by a water spray. The condensing surface of
these pipes is 1,115 square feet, the decrease of temperature 20°
to 26° centigrade (68° to 79° F.).

"(d), (e) Two scrubbers follow the pipe condensers; they are
cylinders of 3 feet 4 inches diameter and 16 feet 5 inches in height,
and contain a series of plates so arranged that the gas entering
these cylinders at the bottom meets the water coming from the top
and is methodically washed. The cylinders are filled over two-
fifths of their height with crushed coke. In one of the scrubbers,
the gases are washed with ammoniacal waters in order to enrich
the latter, in the other with pure water in order to extract as much
ammonia as possible. After the first washing, the depression of
the gases is .15 to .22 meter (5 to 8| inches) of water; after the
second washing .20 to .27 meter (8 to 10J inches). The first
washing lowers the temperature 10° to 15° centigrade (50° to
59° F.) ; the second, 5° to 6° centigrade (41° to 43° F.).

" (/) The tar condenser is built according to the principle of
Pelouze and Andouin, and is.used in large gas works to deprive the
gases of the last particle of tar which they may yet hold. It con-
sists of a series of metallic curtains arranged vertically one behind
the other. These curtains are construced of pieces of wire about
J inch in diameter, placed vertically in frames, f inch apart. Each
curtain is placed behind the other in such a manner that the wire
strings of one correspond to the space between the wires of the
other. The gas, passing these obstacles, is subjected to a succession
of shocks that cause it to yield up the last particle of tar it contains.
To work properly, the needed depression of this apparatus must

TREATISE ON COKE 231

be .04 to .05 meter (1| to 2 inches) of water. This is regulated by
augmenting or decreasing the passage surface of the gases. The
frame bearing the series of metallic curtains is enclosed in a case
on three sides. On the fourth side, the bottom, the seal is effected
by the waters of condensation and the tar. By raising and lower-
ing this frame in the waters, which have a constant level, the passage
surface of the gases is increased or diminished, and correspondingly
the depression of the gases is increased or decreased.

tl(g) The exhauster is of Bourdon's system, exhausting the
gases by means of a jet of steam. The force of the same can be
regulated by the introduction of a needle in a conical opening.
The exhauster is set so that there is neither pressure nor depression
in the expansive tank, the first of the condensing apparatus. In
this way a slight pressure of gas is maintained in the ovens, exclu-
ding the air entirely. The exhauster produces a total depression of
.25 to .30 meter (10 to 12 inches) of water, measured before the
gas enters it; it leaves the exhauster with a pressure of .08 to
.10 meter (3J to 4 inches) of water.

"We have just seen that the gas is drawn through the condens-
ing apparatus by the exhauster, with a depression of .25 to .30 meter
(10 to 12 inches) of water, and that the latter forces it back to the
special burners, already described, in order to heat the ovens.
With the coals of the Company of the Mines of Campagnac, con-
taining 35 to 36 per cent, of volatile matter, it was thought that it
would not endanger the perfect operation of the ovens if 4,000 to
5,000 cubic feet of gas were taken for lighting the plant. This
gasometer, of 2,119 cubic feet capacity, is placed to the left and
back of the ovens. It feeds about 200 burners distributed over
the buildings for separating, washing, unloading, etc. The gas-
ometer is filled at the times when the gas production is greatest,
that is, after the last charge. To effect this, it is only necessary
to shut off the gases from going back to the ovens, at the same time
establishing communication with the gasometer. The latter is
filled in a few minutes; it is then isolated and the gas from the
exhauster goes again to the ovens. The whole operation takes about
7 to 8 minutes, during which time the coke ovens are not disturbed.
This gas for illuminating purposes is purified by lime in two ordi-
nary purifiers, after leaving the gasometer. The whole plant is
thus well and economically lighted, as this gas costs a trifle.

"The products of condensation, tar and ammoniacal water, as
they come from the various condensing apparatuses and the hydraulic
main, are all conducted into a series of settling tanks where the
difference in density permits an easy separation. The tar is drawn
off by a hand pump and put into barrels direct, ready to be sent to
market. The ammoniacal waters are taken up by a pump., driven
by a steam engine, and lifted to a reservoir, the level of which is
higher than any of the apparatus of the plant. From this reservoir
these waters go back to the first scrubber to be concentrated.

232 TREATISE ON COKE

Manufacture of Sulphate of Ammonia. — 'The distilling appa-
ratus for the treatment of ammoniacal waters is a modification of
the apparatus of Mallet. About 70^ cubic feet of these waters
are treated at a time. This quantity arrives in two sheet-iron
receivers, which are placed side by side over a stone pier, in order
to be heated at the same time in the same heating chamber. Before
heating, a small quantity of lime water is put in each receiver.
During this process, which lasts about 4 hours, the mixture is
agitated from time to time with agitators for this purpose, and the
disengaged gases go over into a third receiver containing 70 cubic
feet of ammoniacal waters.

"This third receiver is heated by the return flame of the others
and also by the vapors of ammonia introduced into it. These
vapors of ammonia, however, disengage themselves as soon as the
temperature becomes high enough, and are conducted into lead
tanks that contain sulphuric acid, and uniting with the latter yield
sulphate of ammonia. During this process the sulphuric acid
absorbs also the steam that the vapors of ammonia carry with
.them. The sulphuric acid of 60° uniting with the water yields the
sulphate of ammonia in solution. The solution being evaporated,
a white salt, sulphate of ammonia, is obtained with 20 per cent,
of nitrogen.

"The crystallization is effected in large tanks of sheet iron,
lined with lead, and having a small bottom. These tanks are
13 feet 2 inches long, 5 feet 9 inches wide, and 1 foot 4 inches deep.
Two of these permit, with a crystallization surface of 55 square
feet, the crystallization of 660 pounds of sulphate of ammonia in
24 hours. In the double bottom of the tank steam is introduced,
furnished by the boilers of the ovens. Usually 660 to 770 pounds
of sulphuric acid of 60° is used, and a weight about equal to that of
sulphate of ammonia is obtained. The work is very easy; a single
man can attend to the manufacture of the sulphate of ammonia
that 40 to 50 tons of coal will produce. This is the quantity that
is coked daily. A boy suffices to put the manufactured tar in
barrels. These two can be employed besides this for other work.

"Such are the arrangements of the works of the Company of
the Mines of Campagnac.

"The following statements show the cost of this plant, with the
expense of making coke and saving the by-products:

Cost of Plant — Nineteen Coke Ovens. France

Construction of nineteen ovens $13,177.07

Cost of each oven, $693.53

Cost of condensing plant 10,216.45

Cost of apparatus— tar and ammonia 3,973.67

Cost per oven — apparatus for by-products of tar
and ammonia— $746.85, $1,440.38

Total cost of plant $27,367.19

TREATISE ON COKE 233

The Work of Ovens in the Year 1883 TONS

Coal charged into ovens 14,675

Coke produced ll,006i

Showing product of coke, 75 per cent.

Cost of labor and supplies per ton of coke and its by-products pro-
duced, 73^ cents.

NOTE. — The cost of such a plant in the United States would be about
as follows:

Ovens, each $1 ,000 to $1,250

Condensing apparatus per oven 700 to 750

Tar and ammonia plant 325 to 350

Making the total cost of each oven, including chemical plant, $2,025 to
$2,350, depending on localities. In France the cost would be $1,700 per
oven and apparatus.

"The question may now be raised, if this mode of carbonization
from top down, giving such good results with coals rich in volatile
matters, may also be applied to any other coals that will coke.
We are convinced that it will be advantageous to coke coal con-
taining the 24 to 25 per cent, of volatile matter. The coals of
Campagnac contain 22 per cent, of combined carbon, of which
50 per cent, remains in the coke. It is difficult to estimate before-
hand what amount of the combined carbon of a given coal will
become disengaged and unite with the coke. As to coals having
less than 24 to 25 per cent, of volatile matter and yet capable of
coking, the ovens of Campagnac will give excellent results, if used
as an ordinary oven, dispensing with the gas-condensing and
by-product-saving plant. In fact, they will always be better than
the ordinary ovens, as they develop fully the coking qualities of
the coal, especially if communication be established on either side,
between the retort proper and the top wall flue a. This commu-
nication should be established as near the outside as possible, at g.
Each oven will thus have two openings through which the gases
of distillation are emptied into the top wall flue, and their coming
in contact with air, drawn into the flue by the depression of the
chimney, will ignite them. If the doors and charging holes are
hermetically sealed with clay, the coking process will proceed
exactly in the same manner as if the ovens were heated with
purified gas from the condensing plant. As the carbonization goes
from the top downwards in a sealed retort that has only two
openings for the gas to escape, the dissociation of the gases and
deposits of part of their combined carbon with the coke is exactly
the same as in the ovens at Campagnac. As it is easy to control
the amount of air necessary for combustion, and all the gases of
distillation yielded by the charge of coal are forced to pass through
all the flues, it is easily understood that in such an oven the
maximum temperature is reached which the volatile matter of the
coal can furnish.

234 TREATISE ON COKE

"We can also arrange a group of mixed ovens for carbonizing
coals of 20 to 25 per cent, of volatile matter, and save the by-prod-
ucts of only a number of the ovens. It will thus be seen that these
ovens give better results than many other systems, especially
when coal fairly well adapted for coking is used. By a most simple
arrangement, which does not cause any additional cost in the con-
struction of the ovens, hot air can be introduced into the combustion
chambers instead of cold air. We would always recommend this
arrangement, when coals not rich in volatile matter are carbonized.
The results obtained from hot air have been entirely conclusive."

From the preceding statements of the cost and work of this
coke oven, it is evident that it is well designed for coking coals
inheriting medium volumes of volatile combustible matters, secur-
ing a maximum quantity of deposited carbon from the hydro-
carbons evolved in coking. As previously noted, it can be used to
full advantage in the manufacture of coke without the saving of
by-products, as well as in making coke with the saving of tar and
ammonia, at the option of the management.

Through the courtesy of Mr. Walter M. Stein, metallurgical
engineer, of Primos, Pennsylvania, we present in Fig. 8 a general
plan of twenty-four retort coke ovens with saving of by-products,
with the following description:

"Each oven has two escape pipes a by means of which the
gases reach the hydraulic main b and are then drawn by a Beale
exhauster through the pipe line c into the five condensers d, con-
sisting of concentric cylinders. The Beale exhausters are provided
in duplicate to prevent any stoppage of the plant; each one, how-
ever, is sufficient to exhaust the entire gas of the twenty-four ovens.
From the Beale exhauster, the gas is forced through the scrubbers /.
Two of these are ordinarily used and two are reserve scrubbers.
After the scrubbers follows the steam exhauster g. The pipe line h
conveys the gas back to the ovens to heat the same. - A branch con-
nection is used to fill the gas holder i, which has a capacity of 52,000
cubic feet ; this gas can be used for heating or illuminating purposes.
The small branch pipes k of the pipe line h take the gas into the hori-
zontal wall flues of the ovens, the gas being admitted either into the
top flue only or into all of the three wall flues. The boiler / is heated
with the waste gases, while the surplus gas may also be used for this
purpose, m is the chimney; n, three steam pumps; p, three reserve
pumps; o, the pipe line to take the products of condensation to the
reservoirs from the hydraulic main ; r, the pipe line from the condens-
ers to the reservoir; s, the windlass for raising the door of the ovens;
t, t, the charging larries; u, the main gas flue; and v the ammonia
machine for making sulphate of ammonia. If the gas is used for
illuminating purposes , a purifier is inserted before the gas holder, x is
the coke-discharge side of the ovens ; w, the machine side where pusher
works ; y is the reservoir for tar, and z the reservoir for strong water
of ammonia; while z* is the reservoir for weak water of ammonia."

3^E^^^

Uh&Jl

17303 — vi FIG. 8. GENERAL PLAN OF TWENTY-FOUR RETORT COKE OVENS, WITH SAVING OF BY-PROD'

"",""., _^

SEIBEL'S SYSTEM. WALTER M. STEIN, METALLURGICAL ENGINEER, PRIMOS, PENNSYLVANIA

TREATISE ON COKE 235

Otto-Hoffman Retort Coke Oven. — In the manufacture of coke
for metallurgical uses the main effort is usually directed to the
production of hard-bodied coke, with a full developed cellular
structure. It adds materially to the value of such coke, both as
regards purity. and calorific vigor in the blast furnace, to cause
as large a deposit of carbon, from the volatile hydrocarbon gases
evolved in coking, as is possible from the quality of the coal used
in making the coke; hence, in all retort coke ovens, two special
requirements are demanded, the saving of the fixed carbon of
the coal in coking and the securing of a deposit of carbon from the
evolved gases.

In addition to these points, during the past decade much atten-
tion has been given in Germany, France, and England to saving
the by-products of tar and sulphate of ammonia, which are carried
out in the gases during the process of coking the coal.

The initial efforts in this direction were greatly retarded by
prejudices against the quality of the coke produced. It is quite
probable that these had some foundation, as the early retort coke
ovens were incomplete in their operations and their product of
coke somewhat below the standard requirements. Besides, gas-
house coke was looked upon as a retort coke and considered inferior,
as it was in fact, for metallurgical uses, as compared with the car-
bon-glazed coke from the beehive ovens.

The recent improvements in retort coke ovens have nearly, if
not quite, removed some of these objections, and retort-oven coke
is now afforded an unprejudiced test on its merits.

In the European countries, with agricultural conditions requir-
ing concentrated manures, the by-product of sulphate of ammonia
has become a valuable adjunct in the manufacture of coke, with
the assurance of a home market for all that can be produced.

In the United States of America the conditions requiring the
use of concentrated manures are somewhat different, as there is
still a large proportion of virgin soil that requires little manure;
yet in many sections of the country the sulphate of ammonia
could be used to advantage by the agriculturists. Just how far
the American coke manufacturers desire to invest in by-product
appliances to their coke-oven plants, is a business inquiry demand-
ing earnest and exhaustive consideration. In the presence of a
gradually approaching time when the use of the secondary qualities
of coking coals becomes necessary, it is evident that the retort
coke ovens will come into more general use, in the manufacture of
coke for blast-furnace and kindred uses. Many of these ovens
can be used either with or without the auxiliary appliances for
saving by-products.

We are further indebted to Dr. C. Otto and Company, of
Dahlhausen on the Ruhr, for developing the Otto-Hoffman retort
coke oven, which has in a great measure removed the prejudices
against retort coke previously noted.

TREATISE ON COKE 237

The following description of this oven is taken mainly from
the paper of B. Leistikow, general director of the Wilhelmshuette,*

The coking chambers of the Otto-Hoffman ovens are narrow
chambers, 16 to 24 inches wide, 33 feet long, and 5 feet 3 inches
high to the base of the arch, and are closed at both ends by air-
tight doors.

The construction of these ovens is based on a combination of
the Siemens regenerator according to Hoffman, with the ordinary
Otto oven as a model, to which a large number of improvements
have been made.

Fig. 9 exhibits a longitudinal section of an Otto-Hoffman
coke oven. The pushing engine is on the side a; the coke is dis-
charged on the side b, where it is cooled.

There is no direct connection between the coking chamber and
the side flues. In the covering arch there are three openings c,
which are ports for charging coal into the ovens, and two open-
ings d through which the gases evolved in coking pass off.

Under the base of the arch, in the side walls, there are hori-
zontal flues e, Fig. 10, that connect the entire vertical draft system.

The base flues / running lengthwise of the oven between the
side walls g, are divided into two equal parts h and i. These halves
are connected with regenerators /, /', used for preheating the air
necessary for the combustion of the gases. To each half of these
base flues, tuyere pipes k and k' are connected, which are fed
through the gas-supply pipes / and /'.

The regenerators are long, latticed, brick flues, running across
the whole coking chambers. They are connected at one end, by
means of a reversing valve, either with the air-distributing pipe m
of the condensation plant in Fig. 11, or back with the chimney.

As soon as the oven is heated and the coking process in opera-
tion, the gases evolved escape through the openings d, d into the
supply pipe, similar to the retorts in gas plants, and thence through
the opened valve into the gas receiver, from which they pass to
the condensation plant. From the latter, the gases, freed from
their by-products — tar, ammonia, and benzol — are returned to
be burned around the ovens. On the way to the latter, is a revers-
ing valve, that leads the gas at will into the supply pipe / or /'.

When the gas enters through the pipe / and passes through
the tuyere k by means of the cock o, into the half h of the base
canal, the valve is so set that blast enters the flue p and thence
through the small openings q into the regenerator / and is heated
there, passing upwards through the small openings r into the base
flue h, where combustion takes place. The heated products of
combustion pass through the side vertical flues, then to the hori-
zontal flues e and quickly downwards through the other vertical

*Address delivered on September 5, 1892, at the fifth general meeting
of the German Mining Engineers.

238

TREATISE ON COKE

half to the base flue *, thence through the opening r1 into the regen-
erator /', heating it and passing through the small openings q' into

the flues p • p', and thence through the air valves to the chimney.
The valve is reversed after a certain time, and the gas takes exactly
the opposite direction.

TREATISE ON COKE

239

In the earlier work of this oven, it was thought necessary to
preheat the gas as well as the air ; for this purpose a second regen-
erator was arranged on each side of the oven; this, however, was

discontinued, as it was found to be better to heat the necessary
air, amounting probably to ten times the volume of the gas, to a
high temperature, than to heat the comparatively small volume

240 TREATISE ON COKE

of gas, thereby running the risk of explosions. In all later plants,
there is arranged on each side of the ovens, only one regenerator,
as shown in the accompanying drawings, by which change this
oven has been much simplified without impairing its utility.

The air is first preheated in these regenerators to about 1,000°
centigrade, thereby reducing the amount of gas necessary to heat
the ovens, leaving the excess for other purposes.

The gases evolved from the ovens pass through the valve into
the receiver and are aspirated into the condenser by the aspirator 5,
Fig. 1 1 ; on its way to the condenser the gas passes into an appa-
ratus / wherein it is cooled and separated from particles of coal
dust and a great deal of the tar.

The gases now pass into the condenser u, consisting of a verti-
cal, four-cornered, wrought-iron box, supplied at the top and bot-
tom with false floors, on which are arranged a large number of
wrought-iron tubes, through which cold water flows. The gases
travel around the tubes in opposite directions, while the products
of condensation, tar and ammonia, continually run off below.
The water of the coal passes off as steam, absorbing about 50 per
cent, of the ammonia.

After the gases have passed the cooler, they arrive at the puri-
fier v, which is quadrangular, and the gas divides itself into a
number of tubes that are immersed in water. In the purifier the
gas is first washed with pure water and then with weak ammonia
water, and the remainder of the tar is separated. The apparatus
is so constructed that the water flows in from above and out below
continuously. This water, together with the condensed products
of the air and water coolers, passes into a large vat, where the tar
separates by virtue of its specific gravity.

The same aspirator can be used for forcing out the last par-
ticles of gas, which becoming heated several degrees by the sudden
compression must be passed through another cooler w to be reduced
to a minimum temperature 13° to 18° centigrade.

After leaving cooler w, the gas streams below into the bell
washer x, where it is distributed among a number of bells, which
have a toothed diaphragm extending under the water, whereby
it receives a thorough scrubbing. The washer contains four
to six shelves, one under another, and the water flows from
above downwards, the gas takes the opposite direction and
always is driven against the fresh stream of descending water,
whereby it is completely separated from the least traces of tar
and ammonia.

The purified gas may now be conducted to the ovens for com-
bustion, unless it is desired to separate further products, notably
benzol, which is done in some works, the process, however, being
secret.

The gas, before being forced into the pipes / and I' , Fig. 9, is
led through a small reservoir, which acts as a pressure regulator,

TREATISE ON COKE 241

and indicates to the inspector whether the pressure is constant,
which is necessary to insure constant temperature in the ovens.
The temperature was found to be as follows:

DEGREES
CENTIGRADE

In the hearth flue 1,200 to 1,400

In the side walls 1,100 to 1,200

In the regenerators at the beginning of the air

supply 1,000

In the regenerators at their ends 720

In the chimney, 420

The tar that separates at the bottom of the vat by reason of
its weight is conveyed by a wall pump operating a spiral con-
veyer to the high receiver y, Fig. 12, from which it may be run
directly into cars and taken to the refineries.

The ammonia water, which has collected in the vats, is pumped
to the receiver z, Fig. 13, from whence it is piped to the distilling
room of the ammonia factory. In this latter are two Colonnen appa-
ratuses a, a', of the Grueneberg-Blum system (in other works they
use Doctor Feldmann's apparatus with equally good results), each
capable of working 30,000 liters, in which the water passes down-
wards from column to column, coming in contact with a current
of dry steam which takes out the ammonia and carries it with it.
The ammonia is set free from its compounds by milk of lime in
the space above the cascade column, which is pumped into the
apparatus from the lime reservoir b'.

The steam, saturated with ammonia, is led into sulphuric acid
in the lead-lined chambers cr where it is converted to ammonium
sulphate, or into the condenser dr where it is taken out as ammonia
water. When the chamber acid is neutralized, the liquor is drawn
off and the salt removed to the dropping board z, from whence,
when the lye has entirely drained, it will be transferred to the
lead-lined salt chambers. On the other hand, if the ammonia
water is simply condensed in the cooler d' , it runs into the receiver ef
(holding about 10 tons), whence it may be piped into tank cars
for transportation.

The sulphuric acid may be stored in the receiver /, to be run
off by means of air pumps or siphons as needed, into the boxes c' .
The waste water that runs off from the apparatus a' is led into
vats, where the lime settles out.

The plan and sections in Figs. 12 and 13 exhibit a view of
Plant 3 of the Julienhuette, at Buethen, in East Silesia.

The cost of this oven and the distillation apparatus in Germany
is as follows:

The cost of oven $1,168. 75

By-products apparatus, per oven. 1,636.25

Total $2,805.00

242

TREATISE ON COKE

The cost would be largely increased in the United States,
especially as the apparatus for the saving of the by-products is
erected in duplicate. This duplicate apparatus affords the oppor-
tunity of cleaning and repairing the several parts of these appli-
ances without interruption to the continuous work of the ovens. It

adds to the expense in the construction of the plant, but is found
to be an element of economy in the working of these retort ovens.
The Otto-Hoffman oven is usually constructed in sections of
sixty ovens each. A duplicate apparatus for condensing and
exhausting will serve for two sections of ovens.

TREATISE ON COKE

243

The cost of these ovens in the United States has been esti-
mated at $3,300 each. This includes the necessary apparatus for
the saving of the by-products of tar and ammonia sulphate, but
does not cover the patent charge for using this oven.

In the estimates of the value of 'the by-products secured, per
ton of coke made, very large claims have been submitted. With
the use of good coking coal, the net profits have been estimated
as high as $1.52 per net ton of coke produced. It may be pointed
out that this estimate includes the value of 40 per cent, of surplus
gas for heating purposes, which is calculated at 14 cents per ton

244 TREATISE ON COKE

of coke. It is evident that such an estimate is misleading, when
it is considered that tar is now worth at the coke ovens $5 per
ton, and ammonia sulphate $55 to $60 per ton in the market.

An average product of about 1 per cent, of ammonia sulphate
and 3 per cent, of tar can be secured from the carbonization of
coal to make 100 tons of coke. Under present conditions the
value of these at the coke works is $50 and $15, making in all $65,
less the cost of manufacturing the sulphate of ammonia, $34 per
ton, leaving as the maximum net profit per 100 tons of coke made,
$36; or 36 cents per ton.

The value per ton of coke of surplus gas from the ovens will
be somewhat different, depending on the value of coal in the
locality of the coke ovens. An average of 5 cents per ton would
be a safe estimate. This, added to the value of the by-products
of tar and ammonia sulphate, affords a net saving of about 41 cents
per ton of coke produced.

A reference to the table on page 398, Chapter X, will afford
full details.

Dr. F. Schniewind, of New York City, who represents this oven
in the United States, writes:

"As to the life of the plant, the construction of the ovens in
all details is most substantial, reducing repairs to a minimum.
At Hoerde, Westphalia, there is a plant making coke without
saving by-products, that has been running the past 13 years and
requiring very moderate repairs. The coking coal used in Germany
is very different in quality from the American standard, the Connells-
ville coal. It is, as regards coking qualities, poorer throughout.

" In Westphalia, in the Ruhr basin, the most important coal and
coke district in Germany, the coal varies in its character in a sim-
ilar way as in the Appalachian field; the coal becoming more
bituminous in a gradual increase from the east to the west. This
gives a variety of qualities of coal for coking, depending on the
locality of the coal supply. The yield of coke varies from 70 to
85 per cent, of coal charged into ovens.

"The following may be considered an average analysis of West-
phalian coking coal washed:

PER CENT.

Volatile matter 23 . 00

Fixed carbon 67 . 70

Ash 8 . 00

Sulphur -:.. . • 1.30

"The theoretic yield of coke would be about 76.48 per cent.
The washed coal is charged into the ovens in a very moist condition,
holding about 12 per cent, of water. The coke, though it cannot
be compared as to luster with the Connellsville coke, is an excellent
blast-furnace fuel, which stands a heavy burden in the furnace.

"The fuel results of the German blast furnace are very good
indeed if the poor quality of the coke-making coals is considered.

TREATISE ON COKE 245

"In Silesia, the coking coal is of very poor quality. In some
instances, extraordinary measures have to be resorted to in order
to produce coke; the coal has to be disintegrated finely and then
while moist stamped by hand into large sheet-iron casks and
charged into the ovens. It is only in this way, and by the use of
the Otto-Hoffman ovens at a very high temperature, that a coke
suitable for blast-furnace use can be made. ,

" In the Saar district the coal is also very poor. "

Test of the Connellsville Coal in the Otto-Hoffman Ovens. — In

order to investigate the results that might be expected from these
ovens when running on Connellsville coal, I went over to Europe
early in the summer of 1893, in the company of a competent Amer-
ican blast-furnace engineer, who was sent by some capitalists who.
had become interested in this matter.

We had sent to Europe about 18 tons of Connellsville coal,
with which, after some preliminary tests, we charged whole ovens.
The coke made was of most excellent quality, very hard, with
metallic ring and silvery luster.

Some of this coke was placed on exhibition in the mining expo-
sition at Gelsenkirchen, where it caused general admiration, as
not a single brand of Westphalian coke could compare with it.
The Connellsville coal was composed as follows:

PER CENT.

Moisture 1 . 59

Volatile matter « 29 . 18

Fixed carbon 58 . 84

Ash 9.40

Sulphur 99

Total 100.00

The theoretic yield of coke from the above coal is about 68.84
per cent.; in the Otto-Hoffman ovens the products were:

PER CENT.

Large coke 71.1

Small coke 1.2

Breeze.. 1.3

Total 73.6

This result shows, assuming that no fixed carbon has been
burned in coking, a deposit of 4.76 per cent, of carbon from the
hydrocarbons in coking. The result is evidently correct, as the
rich coking coals of Connellsville or West Virginia secure carbon
deposits in the coke oven.

The time occupied in coking Connellsville coal in the Otto-
Hoffman oven was from 28 to 32 hours.

As to the yield of by-products, the Connellsville proved to be
equal to the richest German coals, as will be seen from the following
figures based upon dry coal:

246

TREATISE ON COKE

Locality

Coke and Breeze
Per Cent.

Tar
Per Cent.

Sulphate of
Ammonia
Per Cent.

Cubic Feet Gas,
Per Net Ton
of Coal

Connellsville coal . .
Westphalian coal . .
Silesian coal ....

73.6
76.0
67.0

4.0

30
4.2

1.07

1.15

1.12

9,321
8,744
10,057

In regard "to benzol, the yield from Connellsville coal will be
found richer than that from German coals, which yield from .3 to
.7 per cent, from dry coal. It is difficult, however, to make any
accurate statement, as analytical research is insufficient. The
quality of the by-products obtained from Connellsville coal was
excellent.

The excess of gas, about 40 per cent, of the total production,
is of great value for illuminating and heating purposes. As a
source of light, it has only about one-half the illuminating power
of best illuminating gas, if used with ordinary burners ; but if used
with the modern incandescent burners, its light equals in brilliancy
the electric incandescent lamp. The fuel value may be judged
from the following comparative table:

TABLE OF ANALYSES OF DIFFERENT GASES

Percentage by
Volume

Gas

From
Otto-
HorTman
Ovens

Coal Gas,
Average
American

Coal Gas,
Cologne,
Germany

Natural
Gas

Water
Gas

Producer Gas

Gas
From
Im-
proved
Bee-
hive
Ovens
8

An-
thra-
cite
6

Bitu-
min-
ous

Hydrogen. ....
Methylene
Ethylene

53.32
36.11
1.63
.61
6.49
1.41
.43

46.0
40.0
4.0

6.0
.5

i.5

.5
1.5

55.00
36.00
1.19
1.54
5.40
.87
?

2.18
92.60
.31

.50
.26

3.61
.34

45.0
2.4

45.0
4.0

2.0
.5
1.5

12.0

1.2

270
2.5

57.0
.3

12.0
2.5
.4

27.0
2.5

56.2
.3

13.7
.9

2 6
98

70.0

Benzol
Carbon monoxide
Carbon dioxide . .
Sulph. hydrogen
Nitrogen

Oxygen
Vapor

100.00

100.0

100 . 00

99.80

100.4

100.0

100.9

100.0

Analyses 1 and 3, by Doctor Knublanch; 2, 4, 5, 6, 7, by W. J.
Taylor, A. I. M. E., Vol. XVIII, page 881; No. 8, by the agents
of the English or Smith oven.

The comparison, especially of the percentage of nitrogen, will
show the efficiency of the Otto-Hoffman oven.

At most plants the surplus gas is used for generating steam in
boilers, together with the off heat from the regenerators. The

TREATISE ON COKE

247

248

TREATISE ON COKE

steam produced is .9 pound of four to five atmospheres pressure
for each pound of dry coal coked in the ovens. This is the average
result of 48 hours run (if the time of coking is reduced, the evapo-
ration of water increases) and after all the by-products, including
benzol, have been recovered.

Tar has found two principal uses in addition to its former
applications. The manufacture of tar paper utilizes a fair pro-
portion of this product; the coming briquet industry will in the
future greatly enlarge the demand for tar.

The market for the by-products of tar and the sulphate of
ammonia is reported as fairly good, with an upward tendency.

FIG. 15. OTTO-HOFFMAN BY-PRODUCT PLANT, OTTO STATION, PENNSYLVANIA

The demand for tar has been increased by the change in the
methods of making illuminating gas at the gasworks.

It is submitted that Philadelphia, Cleveland, and Chicago afford
a good market for these by-products.

OTTO-HOFFMAN COKE OVENS AND BY-PRODUCT APPARATUS OF THE
PITTSBURG GAS AND COKE COMPANY*

This plant is shown in plan in Fig. 14 and a photograph of
it in Fig. 15. The ovens, built in four sets of thirty each,
are arranged symmetrically on two sides of the coal-storage
building. The two portions of the coking plant being dupli-
cates, only one of them will be described. Between the two
sets of ovens constituting one-half of the plant is a 25-foot

*W L. Affelder in Mines and Minerals, February, 1899.

TREATISE ON COKE 249

space containing four Cahall vertical boilers of 100-horsepower
capacity each, while in the similar space in the other half of the
plant there is one 200-horsepower Babcock & Wilcox boiler.
Their combined capacity is 450 horsepower, and they furnish
all the steam power needed at the plant. Each oven is 33 feet
long, 6 feet high, and 22 inches wide, with 12-inch walls. The
ovens are built of sandstone and are lined with firebrick. Through
the arched roof there are five circular openings, three being for the
introduction of coal, and the other two for the egress of the
volatile materials. The ends are covered with cast-iron doors
that are raised or lowered by means of a portable windlass on the
top of the oven. Directly below the oven floor extends a narrow,
brick-lined flue crossed midway between the ends by a transverse
partition. This flue communicates with the vertical flues in the
side walls, which are joined at the top of each wall by a narrow,
horizontal flue. Beneath the ends of the ovens and extending
along the entire set are Siemens' regenerators.

Each oven is charged through the openings in the top with
7 tons of coal, crushed to ^ inch and less. A stream of gas that
has been recovered as a by-product from coal that has been pre-
viously coked is introduced at one end of the flue that extends
beneath the floor of the oven through a 2-inch pipe. Here it
meets air that, by passing through the heated regenerator, has a
temperature of about 2,000° F. The influx of air is accelerated by
a fan situated in the space between the two sets of ovens. The
hot air and burning gas pass through the horizontal flue and up the
vertical flues of the front half of the oven into the horizontal flue
near the top of each wall. They then pass down the other vertical
flues and out through the bottom horizontal flue of the rear half of
the oven into the second regenerator. After passing through the
second regenerator the gases are still very hot, and a portion of
their heat is utilized in the boilers before they are allowed to pass
up the chimney. The heat imparted to the coal by the highly
heated floors and walls drives from it all the volatile matter, and
at the end of from 24 to 36 hours, the time depending principally
on the nature of the coal, a mass of red-hot coke, weighing from
75 per cent, to 78 per cent, of the weight of the coal charged, is
removed from the oven by means of a steam ram.

Recovery of the By-Products.— Although many of the German
plants recover tar, gas, ammonia, and benzol, no attempt is made
at this plant to separate the latter from the tar.

Extending along the top of each set of ovens and sloping at a
small angle toward the space between the two sets of ovens are
two 24-inch cast-iron pipes, called tar pipes, into which the volatile
matter passes through double-elbowed pipes extending from two
openings in the top of each oven. The elbows are intended to
catch the greater portion of the soot . thereby preventing its being

250 TREATISE ON COKE

collected with the tar. A third pipe, 18 inches in diameter, between
and above the other two, communicates with both of them near
their ends in order to equalize the pressure, which would otherwise
differ greatly because of the suction applied at their lower ends to
accelerate the flow of their contents. The several tar pipes unite
to form one 36-inch main, which discharges its contents into a
bottomless tank, with its lower part immersed in tar. Almost all
the tar separates, by virtue of its specific gravity, from the gases
with which it is mixed, and flows in a slow, but steady, stream
into a brick-walled cistern 100 by 20 feet, while the gases pass into
the condensing house directly beyond this cistern.

The gases pass up through three tall, cylindrical, sheet-iron
washing tanks, in which sprays of cold water wash out most of
the tar still present, together with a considerable portion of the
ammonia. The gases are then led through several cooling tanks,
which are nearly filled with pipes containing circulating water.
Three small washers, or scrubbers, are next employed to remove
the last traces of tar and almost all the remaining ammonia. The
gases, which now consist of the ordinary coal gas, with a very
small percentage of ammonia, are run through compressors in
order that the pressure will meet the requirements of Wood's mill,
in McKeesport, to which the gas is piped. After having been com-
pressed, the gases are again cooled and washed, this final washing
taking out the remaining traces of ammonia. Besides being used
in McKeesport, the gas is used at the coking plant both for heating
the ovens and for illuminating purposes.

The tar is pumped from the cistern into a large storage tank,
from which it is run into tank cars and shipped to refineries. Since
all the water employed in washing the gases is run into the tar
cistern, the ammoniacal liquor must be pumped continually from
above the tar into a storage tank, in order to prevent its being
carried away with the tar. From the ammonia tank, the liquor
flows through pipes to the ammonia house, which adjoins the gas-
washing plant. It is introduced at the top of two cylindrical,
cast-iron tanks, together with lime water, while a jet of steam is
admitted at the bottom. The heat supplied by the steam acceler-
ates the liberation of ammonia gas, caused by the lime uniting with
the acid radical of the various ammonia salts present. The excess
of steam carries off the ammonia as NH£)H, through a pipe at the
top of each tank. The ammonia then passes into vats containing
hot sulphuric acid, in which the following reaction takes place:

2NH4OH + H.2SO4 = (NH4)2SO4 + H2O

When the solution becomes saturated with ammonium sulphate,
the latter settles to the bottom of the vats and is removed by
means of perforated ladles, and is dried in a centrifugal dryer.
A small portion of the ammonia is sold as aqua ammonia, instead
of converting it into the sulphate.

TREATISE ON COKE 251

Not only does the company obtain a greater yield of good coke
than is obtainable from the same coal when used in beehive ovens,
but it also obtains a large quantity of valuable by-products.
According to the statement of the superintendent of the plant, the
yield of coke varies from 75 per cent, to 78 per cent. ; of tar, 5 per
cent, to 6 per cent.; of ammonium sulphate, 1.25 per cent, to
1.45 per cent.; and the amount of gas is 10,000 cubic feet per ton
of coal. He also stated that a number of the consumers of the
coke made at the plant preferred it to that made in the Connells-
ville region. The fact that the coke finds a market as far west as
Kansas City, Missouri, speaks well for its quality. That the
by-products are of superior quality is shown by the large and
ready market for them.

A few words might well be said in this connection by way of
comparing the relative merits of the Otto-Hoffman and the beehive
oven as coke producers. It has been shown by actual experiment
that the yield from Connellsville coal in an Otto-Hoffman oven was
73.6 per cent., while the theoretic yield was only 68.84 per cent.
The United States Geological Survey reports show the actual yield
from the beehive ovens in the Connellsville region to have been
but*66.84 per cent, in the years 1880 to 1896, inclusive. Even at
the lower limit claimed by the superintendent, the company is
obtaining from its ovens an amount of coke exceeding the amount
that it could obtain from beehive ovens by more than 8 per cent,
of the weight of the coal charged.

Eight men in two shifts of 12 hours each are employed. The
-total coal consumption is between 600 and 700 tons per day.

I am indebted to Mr. Wm. L. Elkins, Jr., President of the
United Coke and Gas Company, and to Mr. W. P. Parsons, Super-
intendent of the Pittsburg Gas and Coke Company, through
whose courtesy I was enabled to make a careful study of the plant.

SCHNIEWIND OVEN

Description of a Plant of 100 Coke Ovens.* — In order to adapt
the Otto-Hoffman process, as practiced in Germany, to the new
requirements, it has had to undergo many changes. I will describe
a plant consisting of one hundred by-product coke ovens of the
latest type of the United Coke and Gas Company. (See Fig. 16.)

Ovens. — The ovens are arranged in two groups of batteries of
fifty ovens each. Each oven a is an air-tight retort, consisting of a
rectangular chamber 43 feet 6 inches long, 17 inches wide, and
6 feet 6 inches high. The ovens are placed side by side, and are
supported on a steel structure, consisting of light I beams, running
the length of the battery, that rest on cross-girders supported by
steel columns. (United States patents Nos. 627,595, 644,368,

*Article by Dr. F. Schniewind.

TREATISE ON COKE 253

644,369, 668,225, 673,928. British patents Nos. 13,325, 1899;
3,335, 1900; 10,589, 1900; 993, 1901. Further patents pending.)

The construction allows the brickwork to be inspected at all
points. The primary object, however, is the uniform distribution
of fuel gas to the combustion chambers for heating the oven
retorts. The retorts are separated by hollow walls that are divided
into ten compartments b, each compartment containing four,
preferably vertical, flues c. An air chamber d is located directly
under the retort. Alongside this chamber and directly under the
vertical flues above referred to are ten combustion chambers e.
The gas supply to each of the chambers is controlled independently,
and a uniform heat is maintained throughout the entire length of
the oven. The air for combustion is admitted through openings /
in the wall between the air and the combustion chambers. The
air is heated to 1,800° F. by a pair of regenerators g placed together
under the center of the battery and running its entire length.
A vertical flue h conducts the air from the regenerator to the air
chamber d under the oven.

The well-known Siemens principle is used in operating the air
regenerators, with reversals every 30 minutes. The fuel gas is
reversed at the same time as the air by means of a suitable valve;
but the gas is not regenerated. The gas unites with the hot air in
five combustion chambers e, ascends through the vertical flues c to
a horizontal flue i above, through which it passes and descends
through the five chambers in the other end of the oven, thence
through the air chamber d and vertical flue connection h to the
regenerator g, and through the reversing valves to the stack. The
regenerators are built entirely independent of the oven structure,
so that their expansion does not affect the oven brickwork.

Coal Handling. — A steel coal-storage bin of a capacity equivalent
to about 2 days' coal consumption is placed between the batteries.
The coal is elevated to the bin from a hopper placed under the
coal-receiving track by a belt or other type of conveyer. A coal
larry of 8 tons capacity runs on a track on the top of the batteries
and under the coal bin. The larry consists of a long, narrow bin
with eight spouts in the bottom, through which the coal is run
into the oven retort through holes in the top of it, and is leveled
by means of a bar worked through a small opening in the doors
at the ends of the oven. The larry is operated by an electric
motor and receives its load of coal from the storage bin, under
which it, passes. A very dense metallurgical coke can be pro-
duced and the output of an oven largely increased by compressing
the coal into a mold slightly smaller than the retort and charging
the mass through the oven door.

Coke Handling. — On the completion of the coking process, the
oven doors are raised and the mass of 6 tons of coke is pushed
on to a movable platform by means of a ram. The pushing ram,
as well as the machine on which it is mounted, are operated by

254 TREATISE ON COKE

electric motors. The coke, after being pushed upon the platform,
is quenched and allowed to cool. The platform is then tilted by
an electric motor and the coke slid off into cars that run on a track
at the back of the machine.

Gas Mains. — The gas distilled from the coal during the coking
process is conducted to the condensing house by two independent
systems of mains that run on top of the battery the entire length,
one on each side. Each oven is connected to each main by a ver-
tical pipe and valve.

During the first part of the process, the rich gas is taken off
through the rich-gas main. The valve to this main is then closed
and the balance of the gas is taken off through the poor-gas main.
When the coking is completed, the valve to the poor-gas main is
closed, disconnecting the oven from both mains.

Condensing Plant. — The gas leaving the coke ovens is divided
into two fractions; viz., the first fraction or rich gas, which is 'sent
out as illuminating gas, and the second fraction or poor gas, which
is used for heating the ovens. The cooling of the gas and the
removal of tar and ammonia are done in the usual apparatus;
hence, it is not necessary to discuss it here in detail. Both the rich
and poor gases are treated in the same manner. The following is
the sequence of the apparatus as shown in the general sketch of
a gas plant for coke ovens, Fig. 17: a, a' are air coolers; b, b' are
multitubular water coolers; c,c' are tar extractors; d, df are
exhausters; e,e' are second coolers intended to remove the heat
produced by the compression of the gas in the exhausters; and
/, /' are ammonia washers.

The rich gas when freed of tar and ammonia leaves the con-
densing plant and passes through pipe g into_the purifying plant h,
and from there into a large storage gas holder for illuminating
gas, from which it goes into the city. The poor gas, after being
treated in the same manner as the rich gas, leaves the ammonia
washers / and passes through two benzol scrubbers i, ir. After
having been freed of its benzol, it flows through pipe / into the
oven-gas holder k. Here it is mixed with producer gas, when
necessary, which will be discussed later, and carried to the ovens
for heating by the pipe /. The benzol extracted from the poor
gas is then transferred to the rich gas, so as to increase its
candlepower.

The tar oil by which the gas is washed runs first from tank n,
through the second benzol scrubber i, into tank m. From here
it is supplied by pump m' into the first benzol scrubber i. The tar
oil enters from tank n with about 5 per cent, of benzol, and finally
leaves washer i with about 15 per cent, of benzol. It is collected in
tank o. From here it is fed by pump o' into still /?, in which the
benzol is reduced again to about 5 per cent. The exhausted oil col-
lects in tank q. From here it is taken by pump qr through the oil
cooler r, in order to be again supplied to tank n for a new absorption.

256 TREATISE ON COKE

The Utilization of the By-Products of the Coke Industry. — The

following valuable paper of Dr. Bruno Terne was read before the
chemical section of the Franklin Institute, Philadelphia, Pennsyl-
vania, October 20, 1891. It exhibits Doctor Otto's efforts in utili-
zing the beehive type of coke oven for saving the by-products of
tar and ammonia.

"About a year ago I had the honor to speak, in the lecture
course of the Franklin Institute, on ammonia, its sources and
technical uses. I dwelt, for reasons that I thought of sufficient
importance, especially on the production of ammonia as a by-
product of the coke industry.

"We have now entered on the beneficial workings of the new
policy of furthering industrial developments in new branches in a
period that requires the technical men in all branches, and especially
in the chemical industries, to call the attention of the capitalists to
the points in which we are behind the times in our developments, to
the points where the resources of our own land are neglected, and
we are far behind the more progressive European manufacturers.

"I thought it of sufficient importance to ventilate the same
question before the chemical section of the institute in order to
create an interest in the circle of the members of the institute, who
are the best judges of such questions, in order to provoke criticism
of my views. I have revised the part of my lecture referring to the
development of the ammonia industry for this purpose, not in the
expectation of claiming new and original ideas, but to secure your
attention to a point that I consider of great importance for the
development of an important branch of the chemical industries.

"We are surrounded by an immeasurable quantity of nitrogen
gas in the atmospheric air. The weight of the atmosphere surround-
ing our earth is calculated to be 10 trillions of pounds, of which
7.77 trillion pounds is nitrogen; but, in spite of this inexhaustible
source of nitrogen, we are not able, in a direct way, to use a single
pound for the production of ammonia. It has long been the
endeavor of the technical chemist to convert the nitrogen of the air
into ammonia, but up to this hour none has succeeded in doing
it with practical results. We are still compelled to use as sources
for the production of ammonia the products of plant or animal life.

"The nitrogen of the air must pass through the channels of
plant life to reach, in the products of the animal body, their highest
degree of concentration. Hoofs and horns, with 15 to 16 per cent. ;
dried blood, with 19 per cent.; hair and wool waste, with 10 per
cent.; and bones, with 5 per cent, of ammonia, are the richest
sources.

"But the products of animal life, however, even if they were
not too valuable otherwise, are by no means sufficient to satisfy the
wants of the present day for the products of ammonia. But nature
has provided an inexhaustible source for hundreds of years to come,
in the residuum of plant life of former periods. In the bituminous

TREATISE ON COKE

257

coal fields and in the deposits of brown coal are lying stored up
billions of pounds of nitrogen waiting to be converted into ammonia.

"The process of gaining this ammonia is incidental to the pro-
duction of illuminating gas, to the production of coke, and to the
production of animal charcoal. In distilling the bituminous coal
we obtain of the weight of coal used, 4 to 6 per cent, of tar and
6 to 10 per cent, of ammoniacal water of 1.8° B.

"As Professor Lunge has shown, the nitrogen contained in the
coal does not yield the amount of ammonia that we might expect:

Possible Yield

Yield of

Possible Yield

of Ammonia Water

Name of Coal

Nitrogen
Per Cent.

of Ammonia
Per Cent.

1.020 Specific Gravity
Per Ton of Coal

Gallons

Wales

.71

1.10

142

Lancashire

1.25

1.52

196

Newcastle

1.32

1.60

206

Scotland

1 44

1 75

226

" But instead of these figures, the practical yield per ton of coal
at the best is only 45 gallons of gas water of 1.020 specific gravity,
generally only 25 gallons, and in some instances, as low as 13 gallons.

"The ammoniacal liquors from distillation of animal refuse are
much richer, but the small quantity produced allows us to ignore
the same as a very insignificant factor in the production of ammonia
salts. The consumption of ammonia in its various forms has grown
enormously in the last 20 years, and the manufacture of illumina-
ting gas is no longer sufficient to supply the increasing demand for
ammoniacal liquors. On the other hand, the inroad that electrical
plants for illumination have been making yearly on the production
of illuminating gas has already been felt, and will be more so from
year to year. The production of water gas and oil gas are other
factors that are cutting down the amount of ammoniacal waters
produced.

"But there is another source for tar and ammonia, which, so far
as my knowledge goes, has, with a single exception, not been
worked in our country.

" Rich as are our resources, we are not rich enough to waste con-
tinually. It seems strange, and nevertheless it is a fact, with all
the ingenuity of the American people in the advancement of the
purely mechanical part of the technical industries, we have been
and are yet slow in the development of the chemical industries.

"The acid manufacturer of Europe, especially of England and
Germany, had commenced, in the beginning of this century, to
make himself independent of the sulphur mines of Sicily by using
the sulphurous ores of his immediate neighborhood and to utilize
the pyrites for making his sulphuric acid. It has been only within '

258 TREATISE ON COKE

the last 20 years that our people commenced to use the ores that
had been lying under their feet, and today even, the United States
consumes more sulphur for the manufacture of sulphuric acid than
any other nation.

"It is the same with productions of tar and ammonia as a
by-product of the manufacture of coke. If you will visit our coal
region today, you will find the nightly sky illuminated from the
fires of the coke ovens, and every one of the brilliant fires bears
testimony that we are wasting the richness of our land in order to
pay the wiser European coke manufacturer, who saves his ammonia
and sends it to us in the form of sulphate of ammonia; and who
also saves his tar, which, after passing through the complex proc-
esses of modern organic chemistry, reaches our shores in the form
of aniline dyes, saccharin, nitrobenzol, etc.

"As far back as 1768, tar had been produced as a by-product of
the coke industry by a chemical process at Fishbach, in the coal
district of Saarbriicken on the Rhineland. The general opinion of
the consumer there was then, and most likely will be here at the
present time, that the coke produced will be of inferior quality.
Against this opinion of the practical coke men, it has always been
held by technical chemists, that the process can be so conducted
as to yield all the by-products and still make a first-class coke.

"Since about 1850, the producers of coke in France, Belgium,
England, and Germany commenced simultaneously the saving of
the by-products.

"At St. Etienne, in France, a system of furnaces was at work in
1862 for which great success was claimed at that time. The gas
and other volatile products of the coke oven were conducted to
an air condenser, in which the tar and ammonia were condensed;
the non-condensable gases were returned to the furnace as fuel.

"Scrubbers and condensers have been improved to insure com-
plete condensation.

"The following average results have been claimed:

PER CENT.

Coarse coke . 70 . 00

Small coke 1 . 50

Waste coke 2 . 50

Graphite 50

Tars 4.00

Ammonia water 9 . 00

Gas 10.58

Loss 1.92

"The net gain after deducting all expenses and without reckon-
ing in the coke was, per oven, in Besseges, which has eighty-five
ovens in operation, 111,446 francs. For eighty-five ovens this
saving amounts to 94,990 francs or about $18,938.

"I give you in the table on page 259 the results reported
from two establishments in France.

TREATISE ON COKE

259

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PQH PH

" I will not endeavor to cover
the development of the coke
industries of Europe for the
whole period since 1850. I have
had occasion to familiarize my-
self with all the conditions of
this industry, and am in posses-
sion of figures and plans of
Doctor Otto's successful ovens,
a view of which I show you.
(See Figs. 9 and 10.)

" In 1883, a system of twenty
ovens was built at the coke
works of Gottesburg, Silesia, the
results from which were so
encouraging that in the follow-
ing year 120 ovens were built.

" I will give you a report from
a manufacturer, who, two sum-
mers ago, visited the Dahlhausen
works of Doctor Otto, at the
mines of Millensiven near Dort-
mund. Here there are two sets
of thirty ovens each, which are
charged alternately every other
day. The gases are conducted
by large iron pipes to a large
basin, where a part of the tar
will be condensed. From there
it is led to the coolers, where
the remaining tar and ammo-
niacal products are absorbed,
and the gas, purified, is returned
to a gas holder, and from there
is redistributed to the coke
ovens, to the boiler fires, and
utilized as illuminating gas
throughout the works. The gas
returning to the coke ovens is
mixed with hot air and enters
the flues of the bottom and
sides. The coke produced is
an excellent product and finds
a ready market everywhere.
It has not the silver gray or
steel color of our Connellsville
coke, but it is quite as good in
quality as ours."

260 TREATISE ON COKE

Festner-Hoffman Coke Oven. — The general design of the Fest-
ner-Hoffman coke oven is to simplify construction and operation
in the manufacture of coke and saving of by-products. The recu-
perative compartments of this oven are somewhat simpler than the
double regenerators of the Otto oven.

In the treatment of dry coals, it is evident that a high heat
with quick application is required in coking such coals; it is also
manifest that an efficient method of heating the air, for mixture
with the returned gas, is absolutely necessary. But the recuper-
ators and regenerators should be designed in as simple and
inexpensive a manner as possible, consistent with efficiency in per-
forming this part of the work in coking. The Festner oven has
the advantage of direct and continuous work, removing the neces-
sity of reversing the air and gas currents, as in the Otto oven,
thus avoiding the risk of explosions.

The most important improvement appears in the horizontal
posture of the side flues in this oven. In practical operations, it
has been made very plain that the oven heat from the combustion
of the returned gas can be regulated much more readily in ovens
having horizontal flues than in those using the vertical posture.
The danger in the latter arises from the tendency to the concen-
tration of excessive heat at certain localities in the oven flues,
destroying the firebrick conduits and lining.

From the study of this oven, it is evident that in its design
some progress has been made in the right direction in reducing its
cost of construction and expense of operation. It is further mani-
fest that additional study along these lines would be helpful in the
introduction of these retort coke ovens in the United States.

Mr. E. Festner, Director, Silesia Coal and Coke Works, in a
paper read before the German Mining Engineers, September 5, 1892,
describes this oven, shown in Fig. 18, as follows:

"The well-known Otto-Hoffman oven is called the regenerative
oven; in distinction to this I will call my Festner-Hoffman oven
the recuperative oven (referring to the similarly constructed Pon-
sard gas furnace), the purpose of which is to dispense with the
continual reversing of the regenerative ovens and to effect a per-
manent heating of the air necessary for combustion. In this work
I was assisted by Coke Inspector Hoffman, a very able engineer
and the father of the Otto-Hoffman ovens.

" During long experience with the coking process, I have always
found the horizontal flues and the somewhat strong side-walled
ovens better than the Coppee ovens with vertical flues. The former
can be worked at a higher heat and can be examined more readily,
particularly in the flues; therefore, I equipped my ovens last year
with horizontal drafts similar to the Simon-Carves system, which
is used to great advantage at Bulmke, near Gelsenkirchen.

"In building this new plant I arranged my appliances for the
saving of by-products, as their advantages are evident. As the

261

262 TREATISE ON COKE

quality of the dry coal used required a very high heat, it became
necessary to heat the air for combustion as high as possible, and
as grave defects appeared in the reversing process, the recuperative
oven was suggested more from necessity than inclination.

"In explanation I will say that I call the chamber where the
coal is placed for coking and the side of oven where the coke pusher
operates, the front side; and the other, where the coke is discharged
and cooled, the rear side. The chamber of this oven is 29^ feet
long, 23 inches wide, and 5 feet 11 inches high. The oven contains,
when full, 6^ tons of washed coal for a 48-hour charge. The
chamber walls are 6 inches thick, and the flue walls about the
same thickness.

" The ovens are combined in groups of thirty each. The hot-air
flues, lying underground, consist of two systems for a battery of
thirty ovens.

"The coking chamber is filled with coal through the three char-
ging ports a. The gas is conveyed through the flues b into the
condensing apparatus. The exhausted gases return through the
pipes c and d and are sent by the hot-air current that enters at e, ev
e2, through the dividing pipes /, /lf on the front, and /2 on the
back. The gases are first led forwards and back in the hot flues
g and glt under the oven bottom; they then rise in the vertical hot
flue h on the rear side, passing through the horizontal flue i to the
front side; they then go backwards in /, and forwards again in ;\,
falling through k to the lowest horizontal hot flue / in order to
reach the central flue m, which leads the gas under the boilers.
After the heating they receive in passing through these two levels,
the gases are led through n,o, and mv

"The air to be heated enters from the outside at p, falls to the
horizontal air canal q, through the flue system r, r^ r2, r3, r4, r5,
and re, as seen in drawing, and is easily warmed in this system
by means of the hot flue /. From here the air is led through the
horizontal air flue 5 to the vertical flues t in order to get to the
main system u, uv M2, and also to v, vv v2, v3, from whence it is led
as hot air through the vertical drafts e, e'lt and e2, to be used in the
combustion. The heating that the air in the flue system under-
goes, through continually impinging against the small piles w, etc.,
is excellent and the heat of combustion rises to 1,650° F. In the
latter-described arrangement is the characteristic of our oven, for
which Hoffman and I have applied for a patent.

"According to the results in question, from this new oven in
Gottesburg, nothing remains to be desired; they can be heated
very high, are easily regulated, and are, according to experi-
ments that I made with similar ones built by me in Hermsdorf,
almost indestructible, so that these new ovens can be recommended
as the best.

"The waste gas from flue m supplies five boilers of 45 horse-
power. With this heat, the boilers not only supply the necessary

TREATISE ON COKE 263

steam for the condensing apparatus, but power for electric lighting
of the whole works, as well as for running various small machines.

"In order to have as small a depression as possible in the hot
flue, a ventilator plant is necessary, which, as in the Otto-Hoffman
oven, helps to regulate the supply of air and leads to a uniform
heating of the hot flue. The slight depression in the hot flue
stops the gas in the chamber from passing through the cracks
in the walls directly into the hot flue and thereby being lost to
condensation.

"The cost of the oven proper, from the excavation to the time
of firing the oven, is estimated, in Germany, at $935. The cost of
oven and by-product apparatus would therefore be as follows, in
Germany :

Oven ' $935 . 00

By-product apparatus 1,600.00

Total $2,535.00

"In the United States, the cost would be somewhat more,
approaching about $3,000 per oven."

No record is given of the work of this oven, but it is fair to
estimate its coke and by-products about the same as the Otto-
Hoffman oven, a charge of 6.889 net tons of dry coal every 48
hours giving 5.166 net tons of coke every 2 days, or 2.583 net
tons daily.

The coal used is given as an average of its quality in the dis-
trict referred to in the foregoing article as follows:

PER CENT.

Moisture . .74

Carbon 84.29

Hydrogen 4.61

Nitrogen 1 . 62

Oxygen 4.77

Ash.. 3.97

Total 100.00

Semet-Solvay Coke Oven. — The Semet-Solvay retort coke oven,
Fig. 19, came into appreciative notice in Europe, in 1887. This
oven was evidently designed to secure three chief elements in the
coking of coal and saving its by-products.

1. To coke dry coals, such as inherit only 15 to 17 per cent,
of volatile combustible matter ; this is secured by the quickly applied
heat during the initial operation of coking, thus obtaining the full
benefit of the fusing matters in the coal and producing the hardest-
bodied coke possible with such quality of coal.

2. To store heat in the oven walls, to be made available in
starting the coke operation after a fresh charge of coal has been
placed in the oven, avoiding the expensive auxiliary arrangements
of regenerators or recuperators.

264 TREATISE ON COKE

3. To secure in a direct and simple manner the by-products
of tar and ammonia in coking, enhancing the profit of the coke
manufacturer.

An examination of the accompanying plans -and sections of
this coke oven will show the general scope of its design. The
oven chamber is usually 30 feet long, 1 foot 4^ inches wide, and
5 feet 6 inches high. These dimensions may be increased or
diminished to meet the requirements of coking each quality of
coal. Its side walls are faced with flued and jointed tiles in hori-
zontal posture, which affords the best condition for the regulation
of the heat and its proper distribution, so as to avoid its destruc-
tive concentration at any part of the oven.

These flued tiles are quite thin, quickly transmitting the heat
from the combustion of the returned gases to the charge of coal.
This heat is sustained by drawing on the heat stored between the
flued lining of the ovens in the dividing walls. This stored heat
is maintained by the return of the surplus heat toward the close
of the coking of each charge, and is ready to be used in supple-
menting the heat of ovens on the introduction of each fresh charge
of coal, avoiding the chilling of the fusing matter in the coal by a
slow process of coking.

In this oven, the massive arch and covering A afford a very
important second heat-storage reservoir for each oven, which
insures the maximum heat at the upper portion of the charge of
coking coal. These two repositories for heat storage, the walls and
the arch, obviate the necessity of auxiliary appliances for heating
the air for combustion of the gases, which are essential in other
systems.

The oven is capable of coking the richer or pitchy coals, but
its chief merit consists in its successful treatment of coals low in
hydrogenous matters, which are difficult to coke in ordinary
ovens. It, therefore, measurably anticipates a time when the
chief sources of the best coking coals shall have been reduced
in extent, and when the coke manufacturer will be compelled
to fall back on the less valuable or dry coking coals to maintain
the coke supply.

The design for an oven to coke the rich or pitchy coals will, in
time, engage the attention of oven builders, reversing the heat
conditions of the Semet-Solvay oven, to produce coke without the
usual inflated cellular structure now barring the use of such coals
for the manufacture of metallurgical coke.

It may be noted that the Semet-Solvay ovens afford sufficient
surplus heat to make steam in boilers, located near the ovens, for
all purposes of all the operations of the manufacture of coke and
saving of the by-products.

Mr. E. Festner, director of the Selician Coal Works, Gottesburg,
reports that a Semet-Solvay oven will coke 1,440 tons of coal,
producing 1,125 tons of coke per year. About 78 per cent, of coke

TUTT

Covering of Red Bricks on Edge

To be laic/ offer fne Masonry nas ae-Hled

Section
AA

Section
3-B

Sect/on
OC

fire Brick

[01

fire Brie ft

U LL

fire Brick

Red BricK

ft)

17303— vi

FIG. 19. DETAILS OF BRICKWORK FOR C

^ Arch e>/
Red Bricks

Arch of
Refractory Bricks

_LL

P/an

Gas

TTt

t1ea+ f/ues

--^G#&

OVENS. THE SOLVAY PROCESS COMPANY

TREATISE ON COKE 265

is obtained from the coal charged; all 24-hour coke. He further
gives the cost of this oven and its appliances, in Europe, as follows:

Cost of oven complete $1,168.75

Apparatus for saving by-products 1,402.50

Boiler plant, heated with gas 490 87

Storage bin and coal mixer 420 75

Total cost per oven $3,482 87

In the United States, the cost, per oven, of such a plant would
exceed the above.

It has been suggested that the use of silica material in the
flued tiles in the oven lining would add to their permanence in
performing their important functions in the oven and reduce
expenses of repairs.

A plant of twelve Semet-Solvay retort coke ovens is now in
operation at the works of the Solvay Process Company, near
Syracuse, New York. This plant has been constructed in a very
perfect and substantial manner with improved appliances for
extracting and saving the by-products of tar and ammonia. It is
designed at some future time to add twelve more ovens to the
present plant, making in all twenty-four ovens. The exhauster
and apparatus for securing the by-products are sufficiently large
to take care of the products of twenty -four ovens or more. The
main design is to obtain coke as free as possible from sulphur,
and at the same time secure the by-products of tar and ammonia.

The plan of this oven is shown in Fig. 19, which has been
kindly furnished by W. B. Coggswell, Esq., general manager of
the Solvay Process Company, of Syracuse. The cost of this plant
is as follows :

Ammonia concentrator $ 1,584. 74

Boilers . 10,210.56

Coal trestle 3,039. 58

Coal- house plant 5,027 . 23

Chimneys 3,107.93

Pusher 3,112.46

Producer 701 . 00

Ovens (12) 28,685.30

By-product building 7,365. 74

Washers (2) 2,856 . 69

Exhausters (2) 2,51 1.16

Shafting 841 . 47

Hydraulic mains (2) 2,281 . 84

Gas condensers (4) 6,521 42

Piping and other contingencies 10U67.32

Total $88,014.44

From this it will be seen that the ovens cost $2,390.45 each;
the ovens with the appliances and pusher will cost $7,334.53 each.
Increasing this plant to twenty-four ovens, and estimating the
cost of the twelve additional ovens at $2,000 each, the aggregate

266 - TREATISE ON COKE

cost of the plant will be $112,014.44. The average cost of the
ovens is $2,195.23 each. The average cost of the by-product-saving
apparatus is $2,472.04 for each oven. It is quite probable that
with a still further increase of ovens the average cost of ovens and
by-product appliances would be much reduced.

The coal used in these ovens is small or fine coal procured
from the Morris Run Coal Company, Tioga County, Pennsylvania.
It is constituted as follows :

PER CENT.

Moisture ' 1600

Volatile matter 19. 1200

Fixed carbon ,- 70 . 7800

Ash 8.9100

Sulphur 7318

The theoretic coke in the above coal is 80.12 per cent.

During the month of June, 1895, 1,656^ net tons of coal was
used in the twelve coke ovens, producing 1,273J net tons of large
coke and 46£ tons of breeze, exhibiting a total product of 1,320 tons
of coke and breeze. The total product of coke is 79.68J per cent,
of the coal charged into ovens; of this 2.80 per cent, is breeze, or
small coke, leaving of marketable coke 76. 87^ per cent. As the
theoretic coke from this coal is 80.12 per cent., it is evident that
very little waste of fixed carbon has been made in coking. On the
other side it appears that very little carbon has been deposited
from the volatile hydrocarbons in coking; this is further confirmed
by the absence of the bright silver glaze that evidences this deposit
on coke.

The daily charge for each oven is 4.6 net tons of coal. The coke
and breeze produced are 3.67 net tons. One oven produces 106.12
net tons of marketable coke per month or 1 ,273.44 net tons per year.

The by-products of tar and sulphate of ammonia made during
the month of June, are as follows:

PER TON OF COAL

Tar 43. 6 pounds

Sulphate of ammonia 9 . 88 pounds

The revised cost of labor in making coke and saving by-products
is given at $1.08 per net ton. It is estimated that with a twenty-
four oven plant this cost would not greatly exceed 60 cents per
net ton of coke made and by-products saved. These ovens are
run continuously with three shifts of men, making the cost of the
work somewhat above other types of ovens. The value of the
by-products, per ton of coke made, is placed at 48 cents.

With the dry quality of coking coal used in these ovens, inherit-
ing only 17 to 19 per cent, of volatile combustible matter, it is
evident that the results of the retort coke ovens clearly indicate
that this is the best oven for coking this rather inferior coal. The
percentage of coke made, 76.875, with its hardness of body and its

TREATISE ON COKE 267

consequent condition to resist dissolution in its passage down a
blast furnace- by the action of the ascending gases, gives it additional
commendation in producing metallurgical coke.

A similar quality of coal coked in the beehive oven afforded
only 61 per cent, of coke rather softer in body than the retort coke,
and consequently less valuable as a fuel in metallurgical operations.

When the several types of coke ovens shall have been considered,
with cost of plant, expenses of operating, and physical properties
of their products of coke compared, a general review of the merits
and demerits of each kind of oven will be submitted. At this time
it can only be pointed out that such an analysis of coking will
embrace two lines of determinations: (1) Whether metallurgical
coke is the prime requirement, with or without by-products as a
secondary matter; (2) when the by-products are the chief product,
with coke only a secondary interest.

With the largely increased cost of a coking plant for saving
by-products, and its increased cost in labor above the coke plants
without the saving of by-products, it becomes a serious consider-
ation whether the market value of the by-products will secure
increased profits to cover increased investment in plant and extra
labor expenses to the coke manufacturer.

In a communication, July 10, 1894, F. R. Hazard, Esq., treas-
urer of the Solvay Process Company, of Syracuse, New York,
states :

"In the matter of the present results of the block of Semet-
Solvay ovens, in Syracuse, we would say that, running on Morris
Run coal, the percentage of marketable coke to coal used was
78.2 per cent. In addition to the coke there is from 2 to 3 per cent,
of breeze. The by-products amount to 42J pounds of tar per ton
of coke, and 16.12 pounds of sulphate of ammonia per net ton of
coke. We will be obliged if you will make this correction in the
revision of your articles.

"We cannot use our small block of twelve ovens for a fair
criterion of either original or operating cost. By the European
practice, the cost of a Semet-Solvay oven is $1,000 against $1,200
for an Otto-Hoffman oven; and the Semet-Solvay oven will pro-
duce double the quantity of coke, requiring but 22 hours against
48 hours for the Otto-Hoffman oven. The cost is for the oven
only, not the by-products. The cost of operating a block of twenty-
five Semet-Solvay ovens, making twenty-eight charges of 4± net
tons each in 24 hours, equal to 126 net tons of coal producing
101.5 net tons of coke, is two engineers and twenty laborers. At
$2.25 per day per engineer, and $1.40 per day for laborers, this
would amount to $32.50, operating cost for 101.5 net tons of coke,
or 32 cents per net ton of coke. One extra man will attend to the
by-product works."

For the large class of dry coals, this oven is admirably adapted to
produce very good metallurgical coke, as good as can be made from

268 TREATISE ON COKE

this dry coking coal. It may be submitted here, as a general princi-
ple, that first-class coke cannot be made from second-class coals.
Twelve Semet-Solvay coke ovens with apparatus for saving the
by-products of tar and ammonia sulphate have been in operation
during the year 1894 at the large chemical works of the Solvay
Process Company, Syracuse, New York. Mr. W. B. Coggswell,
the managing director, has kindly furnished the statement on this
and the following page of the year's product of coke, breeze, and
by-products. The large output of coke is remarkable, as it greatly
exceeds the best record of retort ovens that has come to our notice.
From the strikes at the coal mines during the year, the output of
coke was reduced owing to the insufficient supply of coal.

Experiments in these ovens with Connellsville coal, for the
Illinois Steel Company, afforded remarkable results in the increased
product of coke. It was shown that coke could be made from this
coal in 16 hours that in quality was satisfactory to the represent-
ative of this company, Mr Whiting, who remained at ovens during
the time of the experiments. This indicates a daily output of
coke of nearly 6 tons. During two visits of the writer to these
works, very full statements of the work of the ovens were kindly
furnished.

COKE-OVEN STATEMENT SOLVAY PROCESS COMPANY
FOR 1894

Coal used, total short tons, 2,000 pounds 21,825.60

Coal used per oven, short tons 1,818. 80

Coke produced, total short tons 17,531 20

Coke produced per oven, short tons 1,460. 90

Breeze produced, total short tons 678. 10

Breeze produced per oven, short tons 56. 50

Percentage of large coke to coal 80 . 33

Percentage of breeze 3. 17

Percentage total coke to coal 83 . 50

Ammonia sulphate, total pounds 309,385.00

Ammonia sulphate per oven, pounds 25,782.00

Ammonia sulphate per ton of coal, pounds 14 . 27

Tar produced, total pounds 917,230.00

Tar produced per oven, pounds 76.435.00

Tar produced per ton of coal, pounds 42.20

Owing to insufficient supply during the strike, the production
was limited by the receipts of coal.

WEST VIRGINIA COALS IN SEMET-SOLVAY OVENS

The following figures are the results of a test of Davis, and
Thomas, West Virginia, coals made in Semet-Solvay ovens at
Syracuse, February 23 to 27, 1899. Four ovens were coked for the
by-product test. Duration of coking 24 hours. One oven was
coked 20 hours, and another 22 hours, and in both cases the volatile

TREATISE ON COKE

269

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270

TREATISE ON COKE

matter was practically all driven off. The following are the figures
as to yield of coke, ammonia, and tar from the Davis coal:

Pounds

Per Cent.

Weight of coal used in four ovens at 8,825 pounds
Weight of coke produced

35,300

27 400

Coke yielded

77.62

Moisture in coal .

4.21

Moisture in coke . . .

2.89

Breeze produced

1 270

Breeze equal

3.60

Moisture in breeze

20.00

Taking into consideration the moisture in the coal and coke,
the figures are as follows:

Pounds

Moisture
Per Cent.

Coal
Per Cent.

Weight of coal charged
Weight of dry coal
Weight of coke produced
Weight of dry coke

35,300
33,814
27,400
26,609

4.21

2.89

Yield of large coke

78.69

Weight of breeze

1 270

20 00

Weight of dry breeze.

1 016

Yield of breeze

3.00

Total yield

81.69

The by-products per 2,000 pounds of coal are: sulphate of
ammonia, 18.51 pounds; tar, 41.14 pounds; gas, 8,000 cubic feet.

ANALYSIS OF DAVIS COAL AND COKE

Coal

Per Cent.

Coke
Per Cent.

Volatile matter

23 720

1 1200

Fixed carbon . . .

68 . 370

88 6000

Ash

7 910

10 2800

Sulphur . . . . .'

.737

.6890

Phosphorus

.0092

The following is the test of Thomas coal :

Pounds

Per Cent.

Weight of coal used in three ovens at 9 945 pounds

29 835

Weight of coke produced. .

22 760

Coke yielded. . . . .

76.28

Moisture in coal

3.00

Moisture in coke
Breeze produced

1,215

2.00

Breeze equal .

4 07

Moisture in breeze

25.00

TREATISE ON COKE

271

Taking into consideration the moisture in the coal and coke,
the figures are as follows:

Pounds

Moisture
Per Cent.

Coal
Per Cent.

Weight of coal charged

29 835

3 00

Weight of dry coal

28 940

Weight of large coal

22 760

2 07

Weight of dry coke

22 ^0^

Yield of large coke

77 01

Weight of breeze
Weight of dry breeze

1,215
912

25 . 00

Yield of breeze

31 n

Total yield .

Qf) 1 1

The by-products for 2,000 pounds of coal are: sulphate of
ammonia, 20.66 pounds; tar, 47.96 pounds; gas, 8,500 cubic feet.

ANALYSIS OF THOMAS COAL AND COKE

• .• ;' ".-. - • '• v~

Coal
Per Cent.

Coke
Per Cent.

Volatile matter

25 420

1 200

Fixed carbon

63 400

85 450

Ash .

U180

i ^ i^n

Sulphur

678

663

Phosphorus

Crushing strength

COMPARISON OF SEMET-SOLVAY TESTS

Volatile
Matter
Per Cent.

Fixed
Carbon
Per Cent.

Ash
Per Cent.

Sulphur
Per Cent.

Phos-
phorus
Per Cent.

Connellsville coal

29 02

61 61

9 37

770

Connellsville coke
Davis coal
Davis coke. .

1.85
23.72
1 12

87.07
63.57
88 60

11.08
7.91
10 28

750
.737

669

.0180

0092

Thomas coal. .

25 42

63 40

11 18

672

Thomas coke

1.20

85.45

13.35

.665

The above analysis of Connellsville coal is fully 2 per cent,
below the average of usual volatile matter, and the phosphorus is
also higher than usual. The yield of large coke from Connellsville
coal was smaller than that from West Virginia coal, due to the
higher percentage of volatile matter. The tests show that not
only none of the fixed carbon is lost in the retort type of ovens,

272

TREATISE ON COKE

273

but that there is an increase over the theoretical yield; this is
probably deposited by the escaping gases. The same results are
obtained from all coals.

Recent Improvements in Semet-Solvay Ovens. — The following
description of the recent improvements in the Semet-Solvay coke
oven has been furnished by the general manager and engineer of
the Semet-Solvay Company, Mr. W. H. Blauvelt:

Fig. 19 exhibits the longitudinal and cross-sections of this oven
in its normal condition as constructed at the experimental plant at
the Solvay-Chemical Works, Syracuse, New York. Since its instal-
lation at these works this normal type has been mainly followed in
the construction of coking plants in various localities in the United

FIG. 21 (a). VIEW OF REAR END OF SEMET-SOLVAY COKE PLANT AT
DUNBAR, PENNSYLVANIA

States. These ovens had four horizontal lines of heating flues. The
coking chambers were 30 feet long, 16^ inches wide, and 5£ feet
high, affording a daily output of marketable coke of 4.4 tons.

Fig. 20 shows the longitudinal and cross-sections of the enlarged
and improved oven. It will be evident that an additional heating
flue has been added to the height of this overt, giving it five heating
flues. Its length has been increased from 30 to 35 feet. The output
of marketable coke from this enlarged oven is given as 7 to 9 tons
per day. The largely increased capacity of this oven has evidently
been secured by the enlargement of its length and height, as well
as from the compression of the charge of coal from its increased
height. The width, 16^ inches, remains unchanged.

Semet-Solvay Plant at Dunbar, Pennsylvania. — Fig. 21 shows
three views of the Semet-Solvay plant of fifty by-product ovens
built in 1895, adjoining the plant of the Dunbar Furnace Company.

274

TREATISE ON COKE

The coal used is Connellsville coal. This plant was one of the
earliest Semet-Solvay plants in the United States and the ovens
are built of the early type illustrated in Fig. 19. There are two

w OF RAM AND FRONT OF OVENS

symmetrical batteries of twenty-five ovens each. A detailed
description of these ovens will be found in Mines and Minerals,
February, 1900, page 297.

FIG. 21 (c). VIEW SHOWING ARRANGEMENT OP BY-PRODUCT APPARATUS

The following is Mr. Blauvelt's letter in regard to the present
status of the Semet-Solvay oven :

TREATISE ON COKE 275

SYRACUSE, N. Y., June 19, 1903.
MR. JOHN FULTON, 136 Park Place, Johnstown, Pa.

Dear Sir: — Since the last edition of your book was published, the
growth of the Semet-Solvay oven has been very rapid and there are now
in this country nearly 1,100 civens, either in operation or under construc-
tion. The principal advance has been in the size of the units, that is, the
size of the ovens and the number of ovens in a block. In 1895, the standard
block of Semet-Solvay ovens was twenty-five ovens, each having a capacity
of 4.4 tons of coal. Now the ovens are built forty in a block, with a capacity
of from 7 to 9 tons each, so the unit has risen from 110 tons of coal per day
to 360 tons per day. The increase in the capacity of the ovens has been
obtained mainly by increasing the height. The height of the charge was
formerly 4 feet UTS inches; now the standard is 6 feet 2f inches, and we
have successfully operated ovens 9 feet high, and 130 of these largest ovens
are in the course of construction. The length has also been increased from
30 feet to 35 feet. It was thought that the increased height might have
some effect on the physical quality of the coke, making it more dense near
the bottom of the oven, but it has not been found to be the case. There
is no visible increase in density in the coke on account of the higher ovens.
We have not found it desirable to change the width of oven originally adopted
in this country, namely an average of 16£ inches. This width permits
almost all coals to be coked thoroughly .in from 22 to 24 hours, and all
things considered, this is found to be the most advantageous coking time.
Wider ovens have been tried up to 20 inches, but the output of coke per
day has proved to be less than with the standard width.

Other improvements about the ovens themselves have been of a minor
nature, mainly the perfecting of details, looking to more economical and
efficient construction. Electricity has been substituted for steam on the
pushers and for man power in the handling of the charging larries. There
has been no opportunity for improvement in the control of the gas in the
flues or the regulation of the heat on the ovens, as these essential points
have always been thoroughly under control and entirely satisfactory. The
introduction of our inclined coke car, which permits the very even distribu-
tion of the coke as it is pushed from the oven, over a large surface, thus
permitting prompt and efficient quenching with a minimum of moisture,
has entirely overcome one of the former handicaps of retort-oven coke,
namely, the high moisture, and in combination with our system of quenching
by the use of a large stream of water, the coke may be kept quite as dry
as in the best beehive practice. By the use of this coke car the handling
of the coke is reduced to an absolute minimum, and when the furnace stock
house is sufficiently nearby, the coke is delivered directly from the quenching
car into stock-house bins with a minimum of breakage.

Our experience has fully demonstrated the superior merits of the Semet-
Solvay system of main division walls between the ovens carrying the roof
structure in a permanent manner and removing all load from the thin flue
walls, as well as acting as a reservoir of heat, which is drawn upon when-
ever the oven becomes cooled by the charge of fresh coal. The independence
of the flue system in respect to the main structure of the oven permits repairs
to any oven flue to be made without shutting down any of the adjacent
ovens. This is an important point in cases where the coal is of a nature to
injure the flues, necessitating comparatively frequent repairs. Some of the
American coals that have been developed since your first edition have
proved to be quite injurious to the bricks forming the flues. In such condi-
tions this independence of each oven produces quite an important effect
on the average output of a plant.

The rapid exhaustion of the Connellsville field has awakened new interest
in the retort oven, since such a large number of coals throughout this country
are not capable of producing a good coke in the beehive oven, and the coke
users must turn to the retort oven for aid. Many of the coals, while suffi-
ciently pure, chemically, do not give, even in the retort oven, a structure
11

276 TREATISE ON COKE

sufficiently dense to support the furnace burden and resist the dissolving
action of the hot gases in the top of the furnace. Experiments have proved
that this structure can be improved and made entirely satisfactory by grind-
ing the coal to a size of \ inch or T3hr inch and under, and compressing the coal
either by ramming or pressure. The Semet-Solvay Company has followed
this line of investigation very thoroughly and has developed a compression
machine that gives very satisfactory results, overcoming many of the diffi-
culties that have made the use of the machines that have been' employed on
the continent of Europe very unsatisfactory, and at the same time having a
capacity as to time of compression very much superior to any other machine.
These machines are being installed at a number of the Semet-Solvay plants.
In addition to the improvement in the physical quality of the coke, the use
of compression increases the output of the oven from 10 per cent, to 15 per
cent, on account of the increased amount of coal that can be charged.

During the last 3 years, the production of illuminating gas from by-
product ovens has developed remarkably, and now the process is operated
very successfully in a number of places. The Semet-Solvay Company
has been delivering illuminating gas of 18 candlepower to the Detroit City
Gas Company for about a year, and two other plants are being fittecl
up for this purpose. The coke oven has an important advantage over the
old retort system for the production of illuminating gas, namely, that in
the coke oven it is possible to make use of the well-known fact that in the
distillation of coal the portions of the gas coming from it during the early
part of distillation contain much the greater part of the illuminating bodies ;
the latter portion of distillation yields mainly carbonic oxide and hydrogen.
In the coke oven, it is easily possible to use the gases low in illuminating power
for fuel for the heating of the ovens, reserving the higher illuminating gas
for distribution. In the ordinary gas retorts this separation is not possible.

In the by-product side of the operation, improvements have been
mainly along the lines of greater efficiency, increased yield of by-products
owing to greater perfection of apparatus and better knowledge of the condi-
tions that produce the largest yield of by-products consistent with the
always primary point of the best possible quality of coke. The distillation
of the ammonia has been very greatly developed, so that now all apparatus
is of much higher economic efficiency, while permitting the easy production
of crude ammonia liquor up to 25 per cent, ammonia with consequent
saving in transportation costs. The manufacture of aqua ammonia has
also been developed and the many practical difficulties attendant on this
manufacture have been successfully solved, so that we are producing at
several of our plants aqua ammonia of the highest commercial quality.

The successful development of the by-product oven is, of course,
dependent on the ability of the country to utilize the by-products, so as
to equal in consumption the very rapid increase in production. With the
great increase in the cost of material and labor, since your first edition was
published, the costs of construction and operation of plants of by-product
ovens have, of course, increased proportionately, and it is necessary that
the values of the principal by-products, namely, tar and ammonia, should
be maintained at approximately the present figures in order that the con-
struction and operation of these ovens may continue to be attractive.
Those interested in the markets of these by-products are giving the most
careful study to the development of their use in new fields, but at present
there is unquestionable danger that the very large amount of tar and ammonia
that will come on the market in the next year will seriously affect prices.
There is no doubt that the consumption of the country will in time catch
up with the production, as the history of such products has always shown
this to be the case, but it is quite possible that there will be a considerable
period during which practically all profit is cut off from those operations,
of which the by-products are one of the important sources of profit.

Yours very truly,

W. H. BLAUVELT.

TREATISE ON COKE 277

Connellsville Coke From Semet-Solvay Ovens. — The following
report of tests in coking Connellsville coal in Semet-Solvay retort
ovens, and furnace tests of the coke produced, which were made
for the Johnson Company, of Lorain, Ohio, is published by the
special permission of A. J. Moxham, Esq.:

A. J. MOXHAM, ESQ.,

President The Johnson Company,
Lorain, Ohio.

Dear Sir: — In harmony with your instructions, dated March 26,
1895, I have conducted a series of experiments of coking Con-
nellsville coal in Semet-Solvay retort ovens, at the works of the
Solvay Process Company, near Syracuse, New York. The coke
made in the ovens was shipped" to the large blast furnace of the
Buffalo Furnace Company, at Buffalo, New York, and its value
as a metallurgical fuel tested in this blast furnace in comparison
with the best quality of the Connellsville beehive-oven coke, from
the H. C. Frick Coke Company.

The main scope of these practical experiments was to deter-
mine, from actual accomplished work, the relative economies of
the manufacture of coke in these two types of coke ovens, with
their comparative calorific values in the work of manufacturing
pig iron in a modern well-equipped blast furnace.

At this time, considerable attention is being directed to the
economies in the manufacture of coke, with the saving of by-
products in retort or closed ovens. The investigation is stimulated
by the more recent improvements made in the construction of these
ovens, mainly along the elements of securing good metallurgical
coke by increased internal heat in the ovens, in the profits secured
by saving the by-products of tar and ammonia, and by the increased
percentage of coke made from the coal, reducing, in proportion,
the percentage of impurities in the coke.

In addition to these, the plan of these ovens has been simplified
and the cumbersome and expensive regenerators and recuperators
omitted; increased oven heat has been secured by thinning the
inside walls through which the flue heat is transmitted into the
coking chamber of the oven.

With the use of the best coking coals, the competition between
the open and closed ovens is quite close and difficult of exact
determination. Other things being equal, the main effort in the
manufacture of metallurgical coke in the retort ovens is to equal
in calorific value, in blast-furnace work, the standard beehive-
oven coke. But in the manufacture of coke from the lower qualities
of coals, especially those low in fusing matters, the narrow ovens
have undoubtedly established their superior value in this respect.

The large cost of the retort ovens, as compared with the open
or beehive, is the main barrier to their more rapid introduction.
This is as $3,100 in the former to $325 in the latter.

278 TREATISE ON COKE

To make the tests in a fairly comprehensive plan, 2,058jf tons
of Connellsville coal was shipped from the Valley mines of the
H. C. Frick Coke Company to Syracuse, for the initial coking test
in the small experimental plant of twelve Semet-Solvay ovens at
this place. These coking tests, as well as the subsequent blast-
furnace ones, were made with great care, as the importance of such
determinations evidently demanded. It was the first time in the
industrial records that beehive and retort-oven coke, from Connells-
ville coal, were compared as to economy in cost of coking and rela-
tive value in blast-furnace work, on fairly equated conditions.

The following analysis of the Connellsville coal used in the
coking tests at Syracuse, in the Semet-Solvay retort coke ovens,
exhibits a fair average of the coal used:

PER CENT.

Moisture, 212° F 840

Volatile combustible matter 31 . 600

Fixed carbon 59. 860

Ash 7.700

Sulphur • 820

Phosphorus 008

The theoretic percentage of coke that can be obtained from the
above coal is 68 per cent. This assumes that no fixed carbon is
consumed in coking and that no carbon is deposited from the tar
gas in the oven. In the modern beehive oven, 12 feet by 7 feet,
some of the fixed carbon is consumed in the oven by the admission
of air. At the same time, the percentage of its coke is increased
by the bright glaze of deposited carbon.

Two very careful tests were made to determine the percentage
of coke made in the Semet-Solvay oven from Connellsville coal.

No. 1 test charge, 9,200 pounds of coal, produced 6,580 pounds
large coke, 164 pounds breeze, and 256 pounds dust and refuse.

No. 2 test charge, 9,000 pounds of coal, produced 6,349 pounds
large coke, 80 pounds breeze, and 198 pounds dust and refuse.

TEST No. 1 TEST No. 2

PER CENT. PER CENT.

Large coke 71 . 52 70. 55

Breeze 1.78 .88

Refuse, pitch, etc 2.63 2.20

Total coke 73.30 71.43

Average large coke 71 . 035

From accurate determinations of the percentage of furnace
coke produced from Connellsville coal in the beehive and Semet-
Solvay coke ovens, it was found as follows: beehive, 66 per cent,
of large coke; Semet-Solvay, 71 per cent, of large coke.

Taking the theoretic coke at 68 per cent., it is evident that a
loss of 4.22 per cent, of carbon has been made in coking in the
beehive oven. The Semet-Solvay, considered from the same
standard, has gained 4.41 per cent, of carbon, or a total gain of
8.63 per cent, of carbon over the beehive product.

TREATISE ON COKE

279

In the beehive, however, the carbon deposit consists of a bright
silvery coating, affording efficient protection to this fuel from
carbon-dioxide gas in its descent in a blast furnace. The carbon
deposit in the Semet-Solvay oven is a dull-colored deposit of car-
bonaceous matter from the tar of the coal in coking. Much more
carbon is deposited in the beehive oven than in the Solvay, but at
the same time much more carbon is consumed in the open oven.

The Semet-Solvay oven is 30 feet long, 16^ inches wide inside
coking chamber, and 5 feet 6 inches high. The accompanying
cross-section, Fig. 22, will show its general features. It is con-
structed with dividing walls, arches, and superstructure of red
brick. It is noticeable that the flue tiles
with their connecting arch, composing the
coking chamber, are entirely independent of
and separate from the red-brick incasing
structure; this secures freedom and room
for expansion in the lining firebrick work of
the coking chamber.

The 16-inch dividing and sustaining
walls perform a double office by supporting
the structure and in storing heat. The
slight cooling of the oven during the few
minutes occupied in discharging the coke is
quickly restored by the heat stored in these
incasing red-brick walls. The 2| inches in
thickness of the inside face of the flue tiles
transmits the heat from the combustion of the returned gas in the
horizontal flues of the oven. The circuit of this heat is continuous
in one direction and can be regulated at pleasure.

The hot gas from the ovens is carried under boilers to generate
the necessary steam for the condensing plant, and for the engine
in discharging the coke from the ovens. The surplus gas can be
used in lighting the works, or in any other way that may be required.

The horizontal flues in this oven can be readily examined and
cleaned. They convey the heat in an even and direct manner,
avoiding any liability to the injurious concentration of heat that
is sometimes found in vertical-flue ovens.

In considering the economies of this type of oven, it is important
to inquire into its wearing properties. It is evident that the red-
brick walls, arches, and superstructure are quite permanent,
requiring no special attention in their repairs. The firebrick flue
lining of the oven is the most liable to breakage and wear. The
twelve ovens at Syracuse have been in use about 2 years, and
are now in good condition. During this time one end flue tile had
to be replaced from a crack found in it. It is quite evident that
the end flue tiles are liable to break or crack from the frequent
changes in temperature at the doors of the ovens. The inside flues
are kept at a nearly uniform heat and are not so liable to crack.

FIG. 22. CROSS-SECTION
SEMET-SOLVAY OVENS

280

TREATISE ON COKE

As the coke is cooled on the outside of the oven, the difference
in temperature inside should not seriously affect the life of the
flued lining tiles. In case of crack or breakage of these jointed
lining tiles, their renewal at the ends of the oven can be made at
a small cost and in a short time. The renewal of the inner flues
will require the cooling of the oven as well as the ovens on either
side of it. This is the most serious aspect of repairs, involving
considerable expense in time and labor. It may be said, however,
that the renewal of the inside tiles is infrequent.

The coking test in these ovens was conducted mainly to deter-
mine the minimum time required with maximum heat to produce
good blast-furnace coke. The various tests included coking periods
ranging from 18 to 26 hours. It appeared that, with well-sustained
oven heat, good blast-furnace coke could be made in 20 hours.
This was the standard minimum time used in producing the coke
for furnace test. Some coke was made by continuing it in oven 26
hours ; this produced a bright hard coke evidently equal in hardness
of body to the beehive coke of 72 hours. From subsequent experi-
ence in the furnace test it is quite probable that 23 to 24 hours
would secure a firmer coke, which would bear faster furnace driving.
The coking tests began April 16, and closed May 17, 1895.
As before noted, there are only twelve Semet-Solvay ovens at
the Solvay Process Works, at Syracuse, New York.

The analyses of Connellsville and Solvay cokes, made at the
laboratory of the Buffalo furnace, by Mr. O. O. Laudig, chemist,
are as follows:

CONNELLSVILLE SOLVAY
PER CENT. PER CENT.

Moisture, 212° F .19 1.25

Volatile matter 1.17 1.61

Fixed carbon 89.02 86.66

Ash 9.62 10.48

Sulphur 90 .77

Analyses of Connellsville coal and the coke made from it in
Semet-Solvay ovens, from laboratory of the Solvay Process Com-
pany, by Mr. J. D. Pennock, chief chemist, are as follows:

>. 3

>. 9

Coal Used
Per Cent.

Coke
Made
Per Cent.

Coal Used
Per Cent.

Coke
Made
Per Cent.

Breeze
Per Cent.

Moisture, 212° F

.470

.200

.000

,070

Volatile matter

30 . 460

2.520

29 020

1-850

4-73

Fixed carbon

62 920

87 . 480

61.610

87 070

78,. 57

Ash

6 620

10 000

9- 370

1 1 . 080

16 70

Sulphur

900

850

.770

750

Phosphorus

025

,037

017

023

TREATISE ON COKE 281

In several tests in these ovens, the coal was moistened with
1, 2, and 3 per cent, and up to 5 per cent, of water, without apparent
change in the quality of the coke produced or in the quantity pro-
duced from this coal.

The effect of the temperature of the oven in the manufacture
of coke is well understood. For dry coals, a quickly applied high
temperature produces the best possible coke. In the case of the
richer coals, such as the Connellsville, a more moderate heat
secures the best results in the coke.

During the progress of coking at Syracuse, in the Semet-Solvay
ovens, frequent tests of the temperature in the flues and interiors
of these ovens were determined by the use of the German Segar
Cones. These have been recorded as follows:

DEGREES DEGREES

FAHRENHEIT FAHRENHEIT

East flue, top. 2,130 East flue, bottom 2,138

West flue, top 2,112 West flue, bottom 2,174

East flue, center 2,222 Within the mass of coke .. 1,994

West flue, center 2,354 Above the mass of coke. . . 1 ,958

Temperature tests taken in the beehive oven immediately
above the coking coal gave the maximum heat, 2,778° F., from
48-hour or furnace coke.

From the foregoing, it will be readily seen that in the coking
operations of these ovens the application of heat is quite different.
The long time required in drawing the coke from the beehive oven
reduces its temperature to 300° or 400° F. The operation of
coking, therefore, begins under a mild heat, increasing gradually
until the high maximum is reached midway in the operation, pro-
ducing a hard-bodied coke with fully developed cells.

On the other side, the rapid discharge of the coke in the Semet-
Solvay oven by a steam-engine pusher reduces the temperature
very slightly, and on closing the doors of the oven for a fresh
charge of coal the average heat is rapidly restored. The oven
heat is, therefore, applied quickly and maintained throughout the
time of coking.

In the open, or beehive, oven the coking of the charge of coal
begins on the upper horizontal surface, reaching down through
the charge gradually to the floor of the oven. The coke crystal-
lizes in a vertical columnar structure in surfaces at right angles to
the horizontal plane of the oven. In the Semet-Solvay oven the
planes of crystallization are at right angles to the vertical side walls
of the oven, and consequently in horizontal postures. The coking
begins at the oven side walls, moving gradually to the central
longitudinal plane of the oven, where a line of demarcation is
developed in a shelly section of coke of inflated physical structure.
The pressure of the charge of coal in the narrow oven compresses
the cell structure of its coke, making it more dense than the broad
oven with shallow charges.

282

TREATISE ON COKE

The general structure of beehive and Semet-Solvay coke will
be noticed in the sketches, Fig. 23.

A beehive oven of 12 feet in diameter, taking the inflated
structure of coke at top and bottom of charge at 3 inches, will
afford 85 per cent, of good coke and 15 per cent, of spongy coke.
The Semet-Solvay oven makes 3 inches of spongy shattered coke
in the middle of the charge, producing 81 per cent, of compact
coke and 19 per cent, of spongy coke. The beehive oven will
make an average of 2 net tons of coke per day. The Solvay will
afford a product of 4 tons per day.

BEEHIVE COKE
48 HOURS

SEMET-SOLVAY COKE
20 HOURS

Compact

Spongy

Dense coke, 3 inches.
Average coke, 9 inches.

Spongy coke, 3 inches.

Arrows show direction of coking.

FIG. 23

The table on page 283 will exhibit, in detail, the physical and
chemical properties of cokes made in these typical ovens.

It will be noted that the Connellsville coke, used at the Buffalo
furnace during the test, was from the Adelaide works of the H. C.
Frick Coke Company. The coal used in making coke in the Semet-
Solvay ovens at Syracuse, New York, was shipped from the Valley
mines of the H. C. Frick Company.

The physical determinations of the Adelaide coke exhibit a
most excellent structure, equaling the standard coke of this region.
The analysis shows its superior chemical purity, excelling in this
respect the standard coke.

The physical tests of the Semet-Solvay coke exhibit the increase
of density in the retort coke as compared to the beehive. These are
typical examples and indicate in a clear and definite manner the con-
dition of coke made in the two principal types of coke ovens. The
increase of cell space will be noticed in the Solvay coke, from the
walls of the coking chamber to the middle of the oven. The average
increase in density of the Solvay coke over the standard beehive
is 12.7 per cent. The compression of cell structure is 11 J per cent.

<U
P^

(a) Standard average
(6) Adelaide, H. C. Frick Co.
Buffalo
(c) Section at oven walls
Intermediate section
Middle section
(d) Used at Buffalo

of beehive and Semet-Solvay,
D. Pennock, chief chemist, The

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284

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NOT
and surplu
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The chemical analysis
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but exceeding the Adelaide
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ash. This analysis dis-
closes the fact that the
Solvay coke retained 1.61
per cent, of volatile com-
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Adelaide coke, an increase
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heat to reduce this volatile
element.

Retort coke should be
somewhat harder bodied
than open-oven or beehive,
coke. But in the table
on page 283 they are just
equal, which sustains the
demand for more oven
heat or longer time in
coking in the retort oven.
It is also important to
reduce the percentage of
the inflated sections of
coke in the middle of the
oven. It is submitted that
by widening the oven
chamber to 20 inches, the
ratio of shattered to
solid coke would be largely
reduced.

The tabulated state-
ment on this page will ex-
hibit the relative costs and
economies in plants of
beehive and Semet-Solvay
coke ovens, to produce
300,000 net tons of blast-
furnace coke per year,
using Connellsville coal.

The breeze from han-
dling the Solvay coke is
much less than that from

TREATISE ON COKE 285

the beehive coke. Little waste is found in careful handling of
Semet-Solvay coke.

The Buffalo furnace, of the Buffalo Furnace Company, is a
modern blast furnace, 18 feet at bosh and 80 feet high. It has
three hot-blast stoves, 18 feet by 70 feet, of the Cowper-Kennedy
type. The blowing engines have surplus power and can increase
the pressure of blast to meet the requirements of different densities
of fuels. The plant is located on the bank of the Buffalo River, on
the west end of Hamburg Street, and receives its ore stock direct
from the lake boats.

The limestone for fluxing comes from Canada, from the upper
members of the Helderberg formation, and is most excellent for
this purpose. Many of its sections are highly saturated with
petroleum. The composition of limestone is as follows:

PER CENT.

Carbonate of lime 97 . 45

Carbonate of magnesia 1 . 40

Oxide of iron, alumina, etc 50

The coke used at this furnace is supplied by the H. C. Frick
Coke Company. It was especially noted as the very best quality
of furnace coke; evidently it had been carefully selected, as no
black ends were visible in the supply examined. It was, therefore,
quite manifest that the best Connellsville beehive coke would be
used in the competitive test with the Semet-Solvay coke. The
whole furnace plant is ably managed by Mr. F. E. Bachman.

Immediately before the commencement of the coke tests, the
furnace was banked a short time to give opportunity for cleaning
the hot-blast stoves. It was assumed that a few days after resump-
tion of work, the furnace would regain its normal condition. It
did not, however, attain uniform work throughout most of the time
of these tests, but it is proper to submit that the irregularities
in its working were about equally distributed over the periods of
the use of beehive and Semet-Solvay cokes; possibly somewhat
more during the use of the Semet-Solvay coke.

This furnace is run chiefly to make open foundry pig iron,
and this was its product during the time of these coke tests, with
some exceptions, when a denser metal, denominated "holly," was
produced.

The mixture was changed slightly during the tests, but was on
an average as follows:

POUNDS

Marquette iron ore 17,000

Winthrop iron ore 878

Rex iron ore * 636

Florence iron ore 1 ,050

Queen iron ore 672

Total.. 20,236

286 TREATISE ON COKE

This mixture gave an average product of 57.29 per cent, of
foundry pig iron.

The weights of the coke charges averaged as follows:

POUNDS

Beehive, Connellsville 10,923

Retort, Semet-Solvay 11 ,830

The limestone charges averaged as follows :

POUNDS

For Connellsville coke . 3,300

For Semet-Solvay 3,600

The general table of blast-furnace operations, on page 287, will
exhibit the results of these tests, with Connellsville beehive and
Semet-Solvay cokes.

These general results require and will be adjusted subsequently,
so as to give to each test the true results of its work as accurately
as can be determined.

The test of the Connellsville beehive coke began May 12, at 6
o'clock A. M., and closed May 16, at 5 o'clock p. M. The Semet-
Solvay coke test began at the close of the beehive coke and ended
May 22, at 2 o'clock A.M. Approximately 5 days were allotted to
each kind of coke.

Samples of each kind of coke were submitted to severe tests for
moisture, in a neighboring foundry core oven, and resulted as
follows: Connellsville beehive coke, 973 J pounds dried to 956
pounds; loss, 1.830 per cent. Semet-Solvay coke, 1,174J pounds
dried to 1,114J pounds; loss, 5.385 per cent. The heat of the core
oven was not determined, but it was estimated, approximately, as
approaching 300° F.

Referring to the analyses of the beehive and Semet-Solvay
cokes, made in the laboratory of. the Buffalo Furnace Company
and at the Solvay Process Works, it will be noted that the beehive
coke has been made from much cleaner coal than that from, which
the Solvay was made. Taking the average of these two determina-
tions for the Semet-Solvay coke would give it, in round numbers,
88 per cent, of carbon, and the beehive 89 per cent, as charged
into the furnace. Equating these cokes for the moisture, it will
reduce the carbon in the Semet-Solvay coke to 84 per cent, and
the beehive to 88 per cent, of efficient available carbon for furnace
use, allowing for the volatile matters in these cokes.

The table shows that there was little waste from soft coke, as
the relations of the two gases, CO2 : CO, were found to be as 1 : 2.47
in the beehive coke, and as 1 : 2.27 in the Semet-Solvay product.
Sir I. Lowthian Bell found the relations of these gases in a large
test of Durham beehive coke as 1 : 2.28, and in Simon-Carves'
retort-oven coke as 1 : 3.32.

The heat in the furnace during these tests was fairly well
sustained. Closing the Connellsville beehive test, a disarrangement

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288 TREATISE ON COKE

of the stock scale reduced the limestone, causing a slight lowering
of temperature of furnace at the opening of the Solvay coke test.

The analyses of six casts of beehive and Solvay iron will afford
comparison of heat of furnace and quality of pig metal produced,
all of which was No. 2 pig.

CONNELLSVILLE SEMET-SOLVAY
COKE COKE

Graphite carbon 3 . 7GO 3 . 600

Combined carbon 170 . 180

Silicon 2.770 2.150

Phosphorus 283 .284

Sulphur 049 .039

Manganese 780 .780

The following condensed statement will show the stock used
and pig iron produced from beehive and Semet-Solvay cokes,
during these tests:

BEEHIVE SEMET-SOLVAY

COKE TEST COKE TEST

Iron ore used 4,260,080 pounds 4,711,190 pounds

Limestone used 729,400 pounds 870,700 pounds

Coke used 2,403,060 pounds 2,775,613 pounds

Pig metal made 1,122 tons (of 2,300 pounds) 1,205 tons

Coke per pound of iron .956 pound 1.028 pounds

Equating the conditions of these cokes and eliminating excess
of moisture, the coke per pound of iron will be for beehive .938
pound, and for the Semet-Solvay .972 pound.

When the further fact is taken into consideration that the Semet-
Solvay coke contained an average of 10.17 per cent, of ash, while
the beehive had only 9.62 per cent, of this impurity, the quantity
of each kind of coke to smelt 1 ton of foundry metal is substantially
equal, and the amount of coal used as Semet-Solvay coke is propor-
tionably reduced.

Introducing the factor of relative proportions of coke made
from a pound of coal in the two types of ovens, the comparison
becomes as follows: beehive, 1.421; Setnet-Solvay, 1.389.

The different grades of foundry metal made during the 5-day
test by each kind of coke are as follows:

No. 1 No. 2 No. 2 PLAIN No. 3 RAGGED TOTAL

TONS TONS TONS TONS TONS TONS

Beehive 20 357 480 237 28 1,122

Solvay 73 487 461 156 28 1,205

It will be noted that the Solvay coke products in pig iron, Nos.
1 and 2, give 560 tons, and the beehive, 377 tons. The lower
products of Solvay coke in No. 2 Plain, No. 3, and Ragged give
645 tons, against 745 tons from the beehive coke. The difference,
therefore, in the heats afforded in the metal made by beehive and
Solvay coke is fairly in favor of the latter.

The most vital inquiry, in these competitive tests, consists
in the relative physical properties of these cokes to stand rapid

TREATISE ON COKE 289

driving in the furnace. It was found that usually the Connellsville
beehive coke could take a blast from 51 revolutions of engine,
while the Solvay coke reached its maximum at 48 revolutions,
a reduction of 5.88 per cent.

The tabulated statement of furnace operations during these
tests shows that the largest output of pig iron from beehive coke
was 259 tons, and from Solvay coke 244 tons; a decrease in daily
product of the latter of 5.79 per cent., which is in harmony with
the reduction of blast when using the Solvay coke. It is true,
however, that the Connellsville beehive coke requires to be reduced
occasionally to 48 revolutions in the blast, but this is the excep-
tion rather than the rule.

The analyses of the gases at top of furnace show that there is no
loss in the Solvay coke from dissolution in its passage down the
furnace, from carbon dioxide; but on the other side it resists this
gas with more firmness than the Adelaide coke. No temperature
tests were taken as to the heat of the gases at top of furnace, but
the relations of CO2 to CO are assuring that no waste from dissolu-
tion from the soft or spongy portions of the fuel had taken place. •

From the denser physical properties of the Solvay coke, it was
anticipated that an increased pressure of furnace blast would be
required to develop its best qualities, but in this we were somewhat
disappointed, as the furnace test reversed the order of blast in a
direction just opposite to the one anticipated. The conclusion is
evident that the Solvay coke requires more heat or more time in
the oven to enable it to stand the blast in driving the furnace equal
to the beehive coke.

In making the coking tests at Syracuse, all needed facilities were
cheerfully afforded, by the chief officials of the Solvay Process
Company. To Mr. Thomas Morris, superintendent of the coke
ovens, I am indebted for many helpful suggestions and other favors.

During the progress of these tests at Buffalo, we were favored
with the presence of Mr. W. B. Coggswell, managing director of
the Solvay Process Company, as well as by Mr. W. H. Blauvelt,
fuel engineer, of this company. The Carnegie Company was
represented by Mr. James Scott, the superintendent of the Lucy
Furnaces in Pittsburg; also, Mr. Charles McCrery, manager of the
Dunbar Furnaces.

Mr. T. B. Baird, vice-president of the Buffalo Furnace Company,
and its manager, Mr. F. E. Bachman, afforded full opportunity to
secure results of tests. Mr. Baird was especially courteous in
extending to the visitors many favors.

Mr. W. T. Richards, of Cleveland, who directs the management
of the M. A. Hanna Furnaces, was very helpful in these tests.

In conclusion, it may be submitted that, while the testing time
of these cokes in the blast furnace has been necessarily limited, yet
it has afforded some reliable indications of the relative values of
retort and beehive coal in the manufacture of pig iron.

290 TREATISE ON COKE

It has been established that the denser coke of the retort oven
could not be driven as fast in the furnace as the more open-celled
beehive coke, in relations of 48 to 51.

It has yet to be shown that the denser retort coke, hardened by
increased heat and time in the oven, can be made to stand a blast,
proportionally stronger than that of the beehive fuel, to equal the
furnace output of the latter in pig metal.

In the relations of density of fuel to speed in a blast furnace,
the fact has been definitely settled that, other conditions being
equal, the speed is in proportion to the density of the fuel. This is
found in the use of anthracite coal (which is a natural coke), in
blast-furnace operations, in its slow calorific energy, as compared
with open-celled beehive coke. The output in pig iron of the former
to the latter is as 3,000 to 8,000 tons per month, or as 1 : 2.66.

The retort oven, however, affords advantages, as from the
Connellsville coal it will yield 71 per cent, of large coke for furnace
use, against 66 per cent, of a similar product of the beehive. This,
with the saving of by-products by the retort oven, compensates for
the difference in its energy or speed in a blast furnace, as compared
with the beehive fuel.

The Semet-Solvay coke oven has been designed under correct
principles, as regards wearing properties and output. Its most
distinguishing property is in its rapid work in coking, which is
30 per cent, shorter in time than its chief competitors.

Very respectfully,

JNO. FULTON,

Mining Engineer.

Johnstown, Pa., July 2, 1895.

The Rothberg by-product coke oven, Fig. 24, belongs to the well-
known horizontal-flue type of which the Semet-Solvay oven can be
considered the prototype. This oven differs from the Semet-Solvay
in that a vertical wall a, Fig. 24 (b), divides the flues in the center
into separate parts and that standard brick are used instead of
special tile. Also, one set of flues serves two adjacent ovens, while
the Semet-Solvay has a solid wall between two ovens, which
necessitates separate flues. The oven chamber is- about 33 feet
long, 16 inches wide, and 6 feet 6 inches high, having a capacity of
7 tons of compressed coal or 5^ tons of loose coal per charge. The
average coking period is 30 hours, but has been reduced to 24 hours
on test. No regenerator chamber or hot stove is used, the air,
which is taken in through openings 6, b, being heated in the recu-
perative flues c and d.

Fig. 24 (b) shows the flues and dampers. From the recuperative
flues, the air passes through vertical flue e and meets the gas from
the first burner at /. From this point, the flame is either forced
through the horizontal flue to the center of the oven and back in
the next lower flue, or is allowed to -pass directly to the next lower

TREATISE ON COKE

291

292 TREATISE ON COKE

flue by opening the damper g in the vertical flue. By observation
through peep hole h, it is easily determined which course the gas
should take to keep the heat of the oven uniform. The second
damper, below the second burner, is adjusted in a similar manner.
The gas of combustion is led through flues i and k under the oven
and back through / and m to the stack through n and the gas
sewer o. The stack draft is regulated on any oven by damper p.
By admitting the gas into the different flues, and by using the
regulating dampers, a very uniform temperature is maintained.
Air can be admitted through any of the peep holes in case it is
necessary for the combustion of the gas.

The advantages claimed for these ovens are: (1) The cost of
construction is reduced by the elimination of the regenerators and
hot-air fans, and the air is sufficiently heated in the inexpensive
recuperative flues. (2) The ovens are easily operated. A uni-
form temperature is maintained without difficulty by the use of
the regulating dampers, as every part of the oven is under com-
plete and independent control. (3) ' Operating expense is reduced
by cutting out the elaborate hot-air system.

This type of oven was first used at the Lackawanna Iron and
Steel Company's plant at Lebanon, Pennsylvania, in 1903, where
an experimental battery of five ovens was erected. The results
obtained from this small battery caused the Lackawanna Company
to install the oven at their Buffalo plant, 282 ovens have been
built and 470 more are in course of construction at that place.

The A. Hiissner Coke Oven.* — This is one of the forms of coke
ovens built mainly for the saving of by-products in coking. Mr.
Hiissner, the inventor, is one of the early experts in the successful
work of securing these products.

The flues in this oven are horizontal; similar in this respect to
Simon-Carves and the Semet-Solvay ovens. This oven differs
from the Coppee and Hoffman types in the posture of its flues, as
they have the vertical posture. The horizontal-flued ovens afford
a very uniform diffusion of heat in a simple and direct manner.

The dimensions of the flues are: length, 29 feet 6f inches;
width, in the middle, 1 foot lOf inches, with a certain taper to
facilitate the mechanical discharge of the coke; height, 5 feet
10J inches. (The original Carves oven is 19 feet 8J- inches, by
2 feet 5| inches, by 4 feet 9 inches high.) The available space in
the Hiissner ovens is 88 per cent, of the total space, and they have
a charge of 5£ tons of finely sifted, dry coking coal.

The charging takes place by four holes a, a; the ends are closed
by doors turning on hinges; the discharging takes place by the
usual steam pushing machine. The end walls between each two
ovens are strengthened by buttresses 6, Fig. 25 (a), which at the
same time prevent air from entering the flues.

*Lunge, 1887.

TREATISE ON COKE

293

The gases are aspirated by means of an exhauster through the
outlet c, and are forced through the condensers and scrubbers,
then return to the ovens and issue by the tube d over the fire-
grate e, where they take fire. The fire gases travel around the par-
tition /, rise at one end and up to the top flue g, and descend
through three horizontal flues and the snore hole h into the main
flue i. The mouth of the gas-inlet pipe d is an annular double
tube, like a Bunsen burner; while the inner tube conveys the air

(*)

FIG. 25. HUSSNER COKE OVEN

for combustion, the combustible gas issues through the annular
space, and both enter at the same time into e. Owing to the dis-
tance that the products of combustion have to travel before they
reach the main flue i (about 100 feet in Carves oven), they were
formerly cooled too much, while the oven bottoms were fluxed.
To avoid this, Htissner (about the same time that Carves took out
his new patent in 1883) introduced a previous heating of the air
to about 300° centigrade in the flues /; it is then conveyed through
the small flue k, contained in the buttress b, partly through / into
the grate space e, partly through / into the top flue g, and in both

294 TREATISE ON COKE

places gets mixed with gas. This does not seem to have met
with complete success; but after adding further gas inlets at m
and m, the fire on the grate e could be left out, the gases sufficing
for heating the retorts.

The cost of erecting a set of one hundred Hiissner ovens in
Gelsenkirchen, Westphalia, according to a published balance sheet,
was: For ovens, buildings, machinery and iron wall, railroads
and water supply, £300 per oven ($1,500). The ovens are charged,
at intervals of 60 hours, with 5^ tons of coking coal.

They are stated by Hiissner to yield from good coking coal as
follows :

PER CENT.

Large coke 75 . 00

Small coke 80

Coke breeze 1 . 20

Tar 2.77

Sulphate of ammonia 1.10

A recent statement claims that, from a charge of 7 tons of
coking coal, 5 tons of coke is obtained in 48 hours; this shows a
product of 71.43 per cent, of coke.

It is also submitted that all the surplus heat from the ovens
can be returned to the steam boilers, or other uses, affording a
much greater heat supply than is usually obtained by the use of
a portion of the gas, deprived of the by-products, to the steam
boilers. In the Otto-Hoffman ovens, 40 per cent, is estimated for
use in generating steam.

It is evident that this oven, from the substantial method of
its construction, its horizontal flues and its simple requirements
in its operation, is destined to meet the wants in the coking of a
wide range of the several qualities of coking coal, with slight
revision in its dimensions.

The Bernard Coke Oven. — Fig. 26 shows the Bernard system
of retort coke ovens. This oven was designed for producing coke
only, but when it is further desired to save the by-products of tar
and ammonia, the arrangement of the flues is changed from the
vertical to a horizontal position.

The first trial battery of these ovens consisted of thirty-six
ovens; the second and more recently completed addition has
eighteen ovens, making in all fifty-four coke ovens at this plant.
These ovens were built by Mr. Walter M. Stein, of Primos, Pennsyl-
vania, for the New Glasgow Iron, Coal, and Railway Company, of
Nova Scotia.

The coke is discharged from the ovens by a steam ram every
40 to 48 hours, according to the regularity or irregularity of the
supply of coal for charging. Each oven is charged with 6 gross
tons of crushed and washed coal, containing 12 per cent, of mois-
ture. The total daily charge for the fifty-four ovens is 162 gross
tons of coal.

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296

TREATISE ON COKE

The one-half of the ovens, twenty-seven, discharged daily,
gives from each oven 2J tons of marketable coke, with less than

FIG. 27.

GENERAL PLAN OF FIFTY-FOUR RETORT COKE OVENS, BERNARD'S SYSTEM,
PATENTED. BUILT BY WALTER M. STEIN

a, battery of thirty-six retort coke ovens, Bernard system; b, battery of eighteen retort
coke ovens, Bernard system; c, chimney for a; d, chimney for b; e, side of coke- pushing machine;
f, coke-discharge side; g, tracks for windlass for raising doors of ovens; h, tracks for larries
for charging ovens; i, tracks for coke-pushing machine; /, main gas flue of a; k, main gas flue of
b; I, a r flues; m, charging holes; n, air holes.

3 per cent, of moisture; the aggregate daily product is therefore
60J gross tons of coke. This exhibits a yield of good coke of fully

TREATISE ON COKE 297

75 per cent., which has been carefully ascertained by coal charged
into the ovens and the merchantable coke produced.

As Mr. Stein writes: "The cost of coke making at Nova Scotia
is, on an average, 15 cents per ton; this includes taking the coal
from the storage bin, charging it into the ovens, pushing the coke
out of ovens, closing the oven doors, sealing them with loam and
watering the coke. This work is performed by a party of nine
men; they could with ease take care of six ovens more if necessary.
These nine men are all ordinary laborers, with the exception of
one, who has charge of the pushing engine. The coke is loaded
on charging buggies by additional men, and conveyed to the blast
furnace by an endless rope. It will be noted that a force of nine
men is required for a plant of retort coke ovens, whether it con-
sists of ten or sixty ovens. For more than sixty ovens, an addi-
tional force of nine men is necessary. It will thus be seen that
the maximum economy in the manufacture of coke in these ovens
is only secured by a battery of sixty ovens.

"The nine men operating this plant of fifty-four ovens are dis-
tributed as follows. Three fillers on top of ovens. Two on coke side
and two on pusher side to clear the doors, level the charges of coal
in the ovens, and seal the doors with loam. One man is required
to cool the coke with water as it is pushed out of the ovens. The
ninth man is in charge of the engine for pushing the coke out of
the ovens. A bank of sixty coke ovens is considered as affording
a fair daily amount of work for the nine attending workmen."

The cost of washing the coal is somewhat below 5 cents per
ton in summer and 10 cents per ton in winter, indicating a yearly
average for this work of 7? cents per ton.

The whole cost of labor in making one ton of coke is as follows :
work at washing plant, 7J cents; work at coking plant, 15 cents;
making a total of 22^ cents. This is exclusive of repairs to ovens
or machinery, supplies, etc.

Mr. Stein further adds, in regard to the cost of repairs to the
ovens per ton of coke: "I beg to say that these ovens have not
cost in repairs $100 since they were started; the only repairs that
will be required are the door blocks on the discharge side, where
some scaling of brick corners occurs by the use of water in cooling
the coke. Occasionally, a hole is burned in bottom of oven by an
irregular supply of air. At long intervals, a door will crack, but
this is infrequent.

"As a general rule, retort coke ovens, well constructed and
skilfully operated, will require very little repairs during the first
10 years. Three years ago, during a long strike of miners in Ger-
many, I had the privilege of examining the inside of numerous
ovens of various types, and they generally looked well inside,
though all or nearly all of them had been in continuous use for
about 10 years; they appeared to be good for at least 5 years of
additional work."

298 TREATISE ON COKE

I have examined a sample of this Nova Scotia coke; it is quite
firm and hard-bodied and is a fairly good furnace coke. This
result has been mainly secured by the admirable preparatory
work in washing the coal, a description of which, by Mr. Stein, is
given on page 69.

In reference to the cost of this bank of retort coke ovens, with
coke-discharge engine, it is somewhat difficult to say, as the mate-
rials for the experimental plant of thirty-six ovens were imported,
which would add to the cost. The principal elements of cost were
as follows :

One coke-discharging engine $ 3,000

Iron parts of coke ovens, complete 9,000

Foundation of ovens and red brick 8,000

Firebrick, all imported 30,000

Superintendence, plans, etc 5,000

Total $55,000

The cost per oven is therefore about $1,000. In the states of
Pennsylvania, Ohio, West Virginia, Missouri, Illinois, Alabama,
and Kentucky, where excellent firebrick is readily and cheaply
obtained, the cost of these ovens should be somewhat under the
cost above stated.

The Brunck Coke Ovens.* — Since the time of the experimental
plant described by the inventor (the late Franz Brunck), in 1894,
a number of installations have been laid down on this system in
Rhenish-Westphalia and elsewhere. In general, the original form
of the ovens and conduits has been retained, but a great improve-
ment adopted in the arrangement of the double flue, whereby the
following advantages have been secured : the two halves of the oven
can be heated independently of each other, the waste gases from
each half being led away separately. Furthermore, the air of
combustion can be heated to a very high degree by being directed
upwards through the checkerwork of firebrick situated between
the two flues, which are maintained at a high temperature by the
waste gases from the oven ; the air is then led over the arch of the
flue and traverses the cooling channels in a direction contrary to
that taken by the furnace gases. In this manner, a large part of
the heat escaping from the ovens is returned to them in the most
direct manner, without any loss by radiation, while on the other
hand, the heating and fusing of the firebrick of the flues are prevented.

A vertical section of the oven and heating conduits is shown in
Fig. 28, path of heating gas and air for support of combustion
being indicated by arrows. This illustration represents one of the
ovens in a battery of one hundred and twenty at the Minister
Stein pit, Gelsenkirchen. Each half of the oven is heated from
the bottom and the two sides, the flames being readily accessible,

*R. Brunck in " Stahl und Eisen."

rh rb

FIG. 28. THE BK

17303— vi

FIG. 29. INSTALLATION OF 120 BRUNCK COKE O^

a, Clarifying tank; b, ammonia works; c, tar and ammonia tanks; d, steam engine; e, water

k, centrifugal separator; /, coke pusher; m, o\

..o.:;::^-.: •.;.;:« .-:;>:;; ^- :».;•: j.:;^-.-.;:^
K COKE OVEN

J L

AT THE MINISTER STEIN PIT, GELSENKIRCHEN

ips; /, tar _and ammonia water pumps; g, cooler; fc, cooler; *, washer; /, saturation boxes;
n batteries of thirty; n, quenching ramp

TREATISE ON COKE 299

easy to regulate, and enabling the heat to be distributed uniformly
over the oven. This thorough control of the heating is highly
important for the supply of heat to the upper part of the charge
of coal, since there the application of heat is from the sides only,
whereas in the lower part of the oven, heat is applied from both
sides and bottom. Again, in consequence of the separate removal
of the waste gases the draft for each half of the oven can be regu-
lated independently.

As can be seen in the drawing, the heating is effected from both
ends symmetrically toward the central portion. The result of
this method of conducting the heating gases, in conjunction with
the central position of the flue underneath the oven, is that the
gas in the oven has a shorter distance to traverse than is the case
in ovens with horizontal, or even vertical, heating flues. This plays
an important part in the question of the recovery of by-products
and the yield of same, since the longer the path traversed by the
gases through the heating conduits the greater must be the dif-
ference between the initial and final pressure to overcome the
resistance opposed to the movement of the current. As, on the
other hand, the pressure of gas within the oven is nearly constant
throughout, there occurs either an escape of gaseous distillation
products from the oven into the heating conduits or of air and
products of combustion from the latter into the oven, it being
impossible to keep the oven walls gas-tight. Both these occur-
rences lead to waste — combustion — of coke and by-products and
to overheating. Owing, however, to the short distance the gas
has to traverse in the Brunck oven, it becomes possible to main-
tain the pressure in the oven and heating conduits at an approxi-
mate equilibrium, and thus prevent injurious communication and
transfusion. The maintenance of this condition of equilibrium
is also greatly facilitated by the system of blowing in the air of
combustion by means of ventilating fans, this procedure rendering
the air supply independent of the natural chimney draft, and
enabling the pressure to be adjusted to suit requirements through-
out the entire system.

The structural arrangement . of strong central pillars between
the heating conduits of each pair of ovens has proved successful
during an experience extending over seven years. These pillars
take up the weight of the oven top and protect the oven from
abstraction of heat by the adjacent oven when the two are in
different stages of the coking process. As explained by the inventor,
one of the advantages of the method of heating by means of
single and double conduits in the walls is that, being relieved of
the weight of the oven top by the central pillar, the walls can be
built thinner and the ovens higher than is possible with systems
wherein the oven walls have to support the roof. Owing to the
more rapid conduction of heat and the reduced thickness of the
charge of coal to be coked, the operation proceeds more rapidly,

300 TREATISE ON COKE

weight for weight, and the capacity of the ovens is therefore
heightened without the fireproof fittings being exposed to as much
wear and tear as in wider ovens with thicker walls. Thanks to
these favorable conditions and the uniformity of heating, the
Brunck ovens that have been at work in the Kaiserstuhl pit for
the last 7 years have needed but very little repair. The removal
and replacement of portions of the walls and sole of the ovens can
be effected without affecting the skeleton; i. e., the central pillars
and roof, owing to the fact that the method of setting the brick-
work has been chosen with a view to such contingency.

In addition to preventing the overheating and fusion of the
brickwork in the walls, the preliminary heating of the air to a
high degree entails the advantage of enabling an excess of gas to
be produced even in the case of coals somewhat deficient in gas-
forming constituents; whereas, in ovens where the air is but slightly
heated, if at all, the whole of the gas is consumed in heating the
ovens themselves. This excess production naturally extends the
limits of the by-product recovery. The excess of gas obtained
when the gas content is 19 to 20 per cent, forms a useful reserve in
the event of the ovens failing by reason of wet coal, bad weather,
or the intervention of Sundays and holidays. Under normal
working conditions the gas finds employment for lighting, heat-
ing, or, more recently, as a source of motive power. For the
latter purpose, the gaseous distillation products of the Brunck
coke oven are particularly adapted, since, in consequence of
the aforesaid equilibrium of internal pressures, the gas is not
contaminated with products of combustion, but contains its high
calorific power.

In comparing two systems of coke ovens, it is evident that
preference should be given to the one that, given the same coal in
both cases, furnishes an excess of gas in addition to waste heat.
If from the gas consumed waste heat alone is produced, the degree
of efficiency of the plant is lower, because waste heat is only
suitable for steam raising, and even when devoted to that use is
subject to loss on the way between the ovens and the boilers.
Moreover, the thorough utilization of the waste heat entails a much
larger heating surface for the boilers than is required by gas fuel.
The importance of heating the air for supporting combustion in
the ovens led to the adoption of a method for utilizing the heat
of the distillation products from the latter. To this end the air
and hot gases are conducted in contrary directions through the
special apparatus, wherein the latter give up their heat to the
former; and as the volume of air required is seven to eight times
that of the gas to be consumed, the large quantity of gaseous
products formed in the coking process is suitably cooled, while the
air is correspondingly heated. There is thus a considerable saving
in condensing water, or in the expense of recooling the water used
in the condensers.

TREATISE ON COKE 301

All coking plants of the Brunck system are provided with a
mechanical leveling apparatus combined with the coke pusher
(see Fig. 28), and set in motion from the latter by a train of cog
gearing. This does away with the old laborious task of leveling
the charge by hand, and the attendant inconvenience occasioned
the workmen by the gases escaping from the oven. When the
machine is used, the surface of the charge of coal is leveled per-
fectly throughout the oven, whereas, when the work is done by
hand, the upper surface generally retains some of the conical form
assumed by the charge in filling. The bar of the machine travels
backwards and forwards the whole length of the oven while the
charge is being introduced, and, by its weight, compresses the
charge to some extent, besides doing the work three times as quick
as by hand labor. As a result of this compression, the weight of
the charge in each oven is increased, and at the same time the
labor of three or four hands per shift is saved in each battery of
sixty ovens.

The set of Brunck coke ovens erected at the works of Jules
Chagot and Company, Montceau-les-Mines, is noteworthy on
account of the provision of a special device for fractionating the
oven gases. The illuminating power of these gases being highest
in those given off in the earlier stages of distillation, these first
fractions are drawn off through a special conduit to the gasworks,
where they are purified and utilized for lighting the town. On
the other hand, during the second period of the coking operation
the valve leading to the gasworks conduit is closed, the gases being
delivered to the condensing plant.

The arrangement of the newest large installation of Brunck
plant, viz., one hundred and twenty ovens at the Minister Stein
pit, Gelsenkirchen, is shown in Fig. 29. The engines exhaust
the total output of gas from the ovens, about 300,000 cubic meters
per 24 hours, and also supply power for the ventilating fans.
The blast engines supplied with the Brunck plant are character-
ized by smoothness of running and low requirements in respect
to repairs, being thereby superior to most of the usual rotary
exhausts, three or four of which will be required to deal with
the above quantity of gas. Being compounded, the engines
maintain the gas at such a constant pressure that the employ-
ment of a gasometer for equalizing the pressure becomes
superfluous.

As shown in Fig. 29, four washers are sufficient to deal with
the ammonia in the gas from the whole one hundred and twenty
ovens at the Gelsenkirchen works, and replace the usual numerous
small washers. This simplifies the arrangement of the necessary
conduits and facilitates supervision and ease of working. The
various machines being driven direct without intermediate shaft-
ing, the work is less subject to interruption in the event of repairs
being necessary in any part.

302 TREATISE ON COKE

The grouping of this plant is as simple for one hundred and
twenty ovens as generally for half that number. The Gelsen-
kirchen plant is capable of coking 250,000 to 260,000 tons of coal,
with 10 to 12 per cent, of moisture per annum, and of turning out
2,800 to 2,900 tons of sulphate of ammonia,, and 7,500 to 7,800
tons of tar. The steam boilers for utilizing the waste gases and
excess of coke-oven gas have a total heating surface of 1 ,400 square
meters, and their favorable situation immediately behind the
center of the four groups of ovens greatly facilitates that utilization,
besides insuring the production of sufficient steam to furnish 550
tons per diem for working the pit , in addition to satisfying the
requirements of the condensing plant.

The Bauer By-Product Coke Oven. — By means of the accom-
panying illustrations and description, which appeared in "Stahl
und Eisen," a new form of retort coke oven, devised by Doctor
von Bauer, which has been adopted by the firm of Fried. Krupp
after a year's trial at the Hanover colliery, owned by the firm, is
shown. Fig. 30 (a) is a cross-section through the center; (b) is
a longitudinal section; (c) is a section through the center; (d) is a
section through the flues; (e) is a partial section, on a larger scale,
through the top of the flues. It is known that most varieties of
coal contain more gas than is required in order to transform them
into coke; hence, not only is all the gas unnecessarily consumed,
but also air is admitted toward the end of the process through the
peep holes in the doors, which helps to lower the temperature at
the expense of the charge; that is to say, at the commencement
there is too much gas and too little air, and at the end of the pro-
cess the reverse condition obtains, notwithstanding that the whole
of the gas is consumed. It is a very difficult matter to regulate the
supply of air and give the proper dimensions to the gas flues. If,
however, there is a means of supplying the gas in a uniform manner
these defects are removed, and in addition there is a surplus of
unconsumed gas, which is of more value than spent gas. The
system under consideration enables one to heat the air in an
equally uniform manner, and to increase the supply of air and gas
as the increasing temperature of the oven renders it necessary,
thus adapting itself to the exigencies of the coking process, which
at first requires less, and later more, of air and gas.

The method can also be applied to the ovens with by-product
recovery in which gas is delivered in uniform quantities from the
gasometer.

A glance at the drawings, Fig. 30, and the perusal of their
description will show that the Bauer oven can be worked (1) as
an ordinary oven; (2) as an oven with condensing apparatus;
(3) as an oven worked on the duplex principle; viz., of abstracting
the gases during that period in the process when they are most
rich in by-products, and allowing subsequently the less valuable

TREATISE ON COKE

303

304 TREATISE ON COKE

gas to pass, without being cooled and afterwards rekindled, direct*
into the flues. By this method, an economy of both heat and of
gas is effected, and the cost of the by-product plant is reduced, as
the hottest and poorest gas is not treated.

The Bauer ovens will take a charge of from 9 to 10 tons, and
the average coking time is from 30 to 36 hours. Considering
their output, it is claimed that they occupy less space, and the
cost of working is less than is the case with some of the other
systems.

The ovens are rilled through the charging holes a, unless it is
preferred to introduce a pressed or pounded cake of coal with the
aid of machinery, and thus do away with these apertures. (1) When
used without by-product recovery the valves to the exhauster are
closed and the stones that close the main flues are lifted. (2) When
used with by-product recovery apparatus the valves to the
exhauster are open and the stones that shut the flues are down.
(3) The duplex principle of working is when methods (1) and (2)
are combined; viz., at first with and afterwards without by-product
recovery. When the oven is without the by-product system the
gases reach the main flues b through three apertures c and thence
pass on to the combustion flues. With the by-product recovery
plant in operation, the purified gases from the gasometer pass into
the mains, and thence into the flues through six openings. With
the union of the two methods, the gases from the gasometer mix
with those of the ovens in which the exhauster is not working, and
then flow into the flues through six apertures. In each case the
flues receive gases or gas mixtures of uniform composition, either
the crude gas disengaged at each particular phase of the coking
process, or the return gas, or else the return gas mixed with the
gases of the ovens that are in operation.

The gases enter at the top ends of the ovens, pass downwards,
then underneath the bottom of the flues, then upwards, and finally,
having received an addition to the quantity from the mains, pass
once more in a downward direction to reach the bottom flue,
situated in the middle of the oven, and thence flow to the boilers
through the outlet pipes. The ovens operate, therefore, on both
sides, namely, from the ends toward the center, and there are on
that account two inlets for the gas. Below the combustion flues
there is situated, between the air flues that are underneath the
bottom flues of the oven, a main air flue; this receives from outside
and from the air flues both cool air and hot air. This air passes up
through airways that are located between the combustion flues,
and then through certain small ports reaches the gases that,
from the main flues, have passed into the chamber above the gas
flues. The coal in the oven is on a level with the chamber where
the gas and air are commingled. In places where the gases flow
in a downward direction, the previously heated air is introduced
through small holes underneath the flues, and in order to admit

TREATISE ON COKE 305

fresh air certain small air passages are effected in the top of the
oven or of the air chambers.

In each half of the oven, in the gas flues, the fresh air is admitted
from below twice and emitted from above as hot air, and once
from above to be emitted below in the same condition. Those
surplus gases that are not consumed in the combustion flues pass
direct from the mains, previous to ignition, into a transverse duct,
which for every ten retorts connects the three mains together, and
from this duct pass through the main outlet to the boilers, or reach
the latter by a separate conduit in order not to become mixed with
the spent gases. Parallel with the return gas pipes, there run
steam pipes for the purpose of moderating, in case of necessity,
any excessive temperature in the gas mains, or in order to main-
tain any particular degree of heat that may be desired. These
pipes, which are of small diameter and are placed above the oven,
are furnished at certain intervals with nozzle-shaped branches,
furnished with taps that lead into the mains. The position of
these steam pipes is shown in the elevation, although they are too
small to be distinctly indicated.

The battery of Bauer ovens consists of eight, with a capacity
of 9 tons. The coal used contains 12 per cent, of water and 67 to
69 per cent, of fixed carbon and ash. The coke yield was, taking
the average of the year during which the ovens were worked
experimentally, 73.2 per cent. Batteries of some other systems in
the vicinity were worked with precisely the same coal, and the
highest yield of the old or the most recent ovens was 68 per cent.

The normal coking time for one of Bauer's ovens is 30 hours.
For about 2 months it was from 32 to 34 hours, and for the rest of
the time, as special men were not told off to attend to so small a
battery, the time has been 48 hours; as soon, however, as the new
installation is complete, the period of 30 hours will be adhered to.

An oven with 48-hour charges will yield in 1 year (360 days)
1,186.5 metric tons of coke, and with 30-hour charges it will yield
1,898.4 tons of coke; that is, when worked without by-product
apparatus. The theoretical yield of coke has been given above
as 67 to 69 per cent., or as smaller than the actual. Such discrep-
ancies are, however, not infrequent. At Creusot, in Bauer's ver-
tical ovens, working with a mixture of coal and anthracite, we have
a yield of 81 £ per cent., although theoretically the coke contents
are put down as 82 per. cent. ; at the Hanover colliery, we have a
yield of 4 per cent, above the theoretical one as before stated,
namely, 73.2 per cent. It is, therefore, not correct to merely indi-
cate the charge for 24 hours, in instituting comparisons. The excess
of over 4 per cent, above the theoretical yield has been maintained
by Bauer's ovens regularly throughout the whole time they have
been in operation, that is to say, for about 15 months; and these
figures are not simply the result of an analysis effected in the
laboratory, but have for their basis the total amount of the coke

306 TREATISE ON COKE

production since the ovens started working. At the Hanover
colliery, Doctor Kassner, Doctor von Bauer, and others, are of
opinion that this excess in the yield is due to the precipitation of
volatile carbon, which is absorbed by the glowing coke in the last
stages of the process. Notwithstanding the experiments of Kass-
ner, many are skeptical on this point, and further investigations
are to be made. The fact of this excess of the yield above the
estimate is, however, well established.

The advantages claimed for these coke ovens are the surplus
of gas unconsumed, the smaller space that they occupy, the low
working expenses, and the absence of any smoke.

Lowe Coke Oven. — In response to a request for information
about the Lowe oven, the following has been received from the
inventor, Mr. T. S. C. Lowe:

NORRISTOWN, PA., July 14, 1903.
MR. JOHN FULTON, 136 Park Place, Johnstown, Pa.

Dear Sir: — Your letter of June 26, to Mr. Herbert Cutler Brown, of Los
Angeles, has been sent to me with the request to write you concerning my
new system of coke and gas production, and it gives me much pleasure to
send you herewith an article recently published in the Progressive Age.

I have been much interested in your former publications, and if possible
would be glad to furnish you with accurate tests of my system, but so far
there have only been experimental plants built, the most important being
that of the Jones & Laughlin Steel Company, and unfortunately it will take
a longer time to get accurate information from that source than you will
probably have before issuing your proposed publication, for the reason that
it has been found necessary to let down heats to arrange some parts of the
apparatus, increasing flue space and stack draft, as well as to arrange to
prevent the indrafts of air caused by warping of door and other frames of
the outer casing. This is easily done, as soon as they can shut down the
ovens long enough to do the work.

These first ovens have been in operation 3 months, and it is desired to
continue them, since it serves to give them information as to all the parts
that are found defective, as you know in all new matters something will
arise that can be bettered. The principle, however, works perfectly, and
cannot be improved on, either in the production of a superior quality of coke,
or the saving of the gases.

In about 2 weeks from npw, however, we shail start up a new plant
better arranged for making tests, at Rockaway Beach, Long Island, and
if you think that your work will be delayed long enough, I shall be pleased
to send you an invitation to go and see this plant operated, for I am sure it
would be an interesting feature for your book, and afford just the information
that is now needed more than ever concerning the production of metallurgical
coke and gases suitable for open-hearth steel work, power, etc.

Very sincerely yours,

T. S. C. LOWE.

New Lowe Coke-Oven and Gas-Making System.* — This new proc-
ess of gas making has now passed the experimental stages, and it
is a proved fact that a superior, hard, heavy, smokeless fuel, fully
equal to the best anthracite, can be made in any locality in the

*By John Haug in the Progressive Age, April 1, 1903: further informa-
tion upon this new process will be furnished by the author at or from his
office, 536 Bourse Building, Philadelphia, Pennsylvania.

TREATISE ON COKE 307

world, from cheap soft coals, and while doing this a larger volume
of gas is saved than by any process heretofore practiced. This
coke, sold under the name of "Lowe anthracite," has been tested
for all purposes for which anthracite has been employed, and in
no instance has it proved inferior, but in many cases far superior
to the natural anthracite. To devise a system to accomplish this
has required, on the part of the inventor, an immense amount of
work and study and the possession of an unusual amount of scien-
tific knowledge. To create a perfect system required, first, a
thorough study of the older methods. The old beehive system was
found to produce a good hard metallurgical coke, but, as a rule,
the yield is only from 50 to 60 per cent, of the coal employed, all
the rest going off in volatile form. It was noticed that, when
care was taken to admit air in the best proportions for securing
high heats, the coke was harder and better and the yield of that
oven was greater than when this care had not been exercised.
The reason for this slight increase in the weight of coke was found
to come from the deposit, on the upper portions of the charge, of
carbon dissociated by the high temperatures from the heavy hydro-
carbons. Under the best conditions of beehive coke making, more
than 50 per cent, of the combustible gases escape from the tunnel
head of the oven unconsumed, which of course accounts for the
immense volume of black smoke always arising from coke ovens
operated in this way. It was this knowledge of what was going
on at the different stages of coking under this system, as well as
the knowledge of what kind of coke would give the best results
in blast furnaces, cupolas, and for domestic and other uses, that
showed the necessity of a radical change in this most important
line of industry.

Without going into the various stages of how he arrived at his
final conclusions, it is evident that Professor Lowe has devised a
system of coke and gas making that is of considerable interest.

The first requisite was to retain all the valuable features of
the beehive ovens, whereby the coal is coked by reflected heat
from the arches of the ovens; second, to maintain continuously
the highest possible degree of heat that the best brickwork would
stand without injury, that all of the heavy hydrocarbons might be
deposited in solid form during their passage upwards and through
the hottest part of the coke; and third, to save all combustible
gases not needed in keeping up the necessary heats.

If fairly good coke could be made in the old way without act-
ually burning more than half the gases arising therefrom, it was
certain that, with a properly constructed apparatus by which the
ovens are never cooled while charging coal or discharging coke,
and where the air admitted for burning gases comes in at from
2,000° to 3,000° temperature instead of cold air as in the old system,
it would be easy to figure that a much larger percentage of the gas
arising from the coking coals could be taken away unburned, and

308 TREATISE ON COKE

either enriched and sold as illuminating gas or employed for metal-
lurgical heating and power purposes without carbureting. But
this required an entirely new construction, and the plan was adopted
which resulted in the ovens being heated by internal combustion
taking place directly over the coal to be coked.

In following out this idea, Professor Lowe has devised a series
of ovens a built within a single steel casing, all having connecting
flues 6, with large regenerator chambers c at each end of the battery
of ovens, and also a steam generator d and stack e at each end con-
nected by flues / and g to the superheaters, as shown in Fig. 31.

To properly heat a large plant under this system requires
about a week, but after the heats are once established the operation
is very simple, and, so far as the brickwork and apparatus generally
are concerned, there is no reason why they should not last 10 to
15 years without repairs. Blast furnaces often run from 7 to
10 years without closing down for repairs, and their work is much
more severe than that of coke ovens.

Under Professor Lowe's system, a much deeper charge of coal
is thoroughly coked in 24 hours than in the beehive oven in 48 hours.

From four to twelve of these ovens are built in each battery.
Therefore, in a four-oven plant, one oven is discharged and recharged
every six hours; in a six-oven plant, every 4 hours; in an eight-oven
plant, every 3 hours; and in a twelve-oven plant, one oven every
2 hours. The greater the number of ovens in one battery, up to
eight or twelve, the more evenly are the heats maintained, although
most excellent results have been obtained in a four-oven apparatus.

In order that the reader may understand how the gas is saved
by this system when it is impossible to do so in the beehive oven,
we would state that the heating of the Lowe ovens and taking off
gases therefrom are alternating operations, while the coking process
is continuous. The gas arising from the coking coals is burned
under the arches of the ovens and over the coking coal, by the
admission of the highly heated atmosphere from one of the regener-
ators, say, for 30 minutes, and the combustion of these gases is
completed while passing from the last oven into and among the
brick checkerwork of the regenerators at the other end, and the
last heats are taken up while passing through open iron checker-
work in entering the stack, say, for 30 minutes; then the stack
valve is closed, and water being sprayed over the piled cast-iron
work, large volumes of steam are generated, which, while passing
through the checkerwork brick, is so highly superheated that it
does not in the least check the coking operations of the coal; and
while this steam passes along from one oven to another through
the series of flues, it not only carries with it the volatile hydro-
carbons being given off in immense quantities, but the steam itself
is decomposed while coming in contact with the heavier hydro-
carbons and the flocculent carbon in the form of lampblack or
soot, when passing through the highly heated brickwork.

310 TREATISE ON COKE

It is believed that in the larger batteries of ovens, for every
30 minutes the gas is burned in the ovens, the gas-recovering
period can be extended to 40 minutes; thus, over 57 per cent, of
all the gas arising from the coking coals is saved, in addition to
all the water gas that the more solid and condensed portions will
produce by their admixture under these high heats, leaving no tar
to be provided for. In fact, the inventor's aim has been to convert
everything about the coal into either a high grade of coke or gas
in a combustible form. He says that, in apparatus making tar,
it is always at the expense of good coke and large volumes of gas,
and there could be no better illustration of this than in the results
obtained in distilling coal in the ordinary gas-house retorts, for
there they get tar in such quantities that the gas engineer is con-
tinually hunting better methods of burning the tar, either under
retorts or steam boilers. The quality of Lowe-oven coke is much
superior to that of gasworks coke. The writer is now superintend-
ing the erection of a number of Lowe coke-oven plants, on both the
Pacific and Atlantic coasts. The largest battery of ovens yet
built is that at the Jones & Laughlin Steel Company's plant at
Pittsburg. They are built inside a gas-tight steel casing, having
a ground space for the ovens and superheaters of 40 by 80 feet,
and contain eight ovens, each 6 feet 6 inches wide by 38 feet in
length. Each oven will take a charge of coal weighing 16 tons.
The brick required for this battery of ovens was about 500,000,
including the regenerators and checkerwork, but it is found that
in future construction this can be considerably reduced without
impairing the efficiency of the ovens.

The steel company has built a large gas holder, and gas mains
are being laid to their various open-hearth steel furnaces. This gas
will either mix with or supplement the natural gas of which their
supply is now so short and the price so high that they have been
compelled for a number of years to make producer gas to help
them out — which is both troublesome and expensive. These ovens
were designed to be ready to go into regular operation some time
in April, 1903.

A test of the ovens in producing coke was made about the
middle of January, principally to settle the questions: (1) con-
cerning the ability to thoroughly coke so thick a mass of coal
(30 inches) and at the same time produce a satisfactory quality
of coke ; and (2) to ascertain whether or not the coke could be dis-
charged from ovens of this size and length without piling up in
the ovens. Much to the surprise of all, the coke pusher designed
for this purpose discharged the entire mass of coke in a solid block,
without the least stoppage or hitch.

These were two very important points to a concern whose coke
production -was 3,000 tons daily, and who planned to increase
that output to 4,000 tons. To make 4,000 tons of coke daily in
beehive ovens would require the maintenance of fully 1,800 of

TREATISE ON COKE 311

them, and as it required one man to three ovens, it would mean a
force under the old system of 600 men daily, as it is nearly all hand
labor. By this new system, fifty men will be amply sufficient to do
all of this work, leaving 550 to go into other more useful branches.

While making the short test of the ovens, it was difficult to
ascertain the exact increase in percentage of coke, but enough
was shown to satisfy Professor Lowe that the increase over the
beehive yield would be fully 20 per cent., and that about 15,000
cubic feet of mixed coal and water gas would be saved per ton of
coke made; or 60,000,000 cubic feet of gas while producing 4,000
tons of coke, which, counted at selling rates of natural gas (10
cents per 1,000) per equal number of heat units, would amount to
$6,000 daily. This, with the 800 tons daily of pure, solid carbon
saved in the coke, and the labor of 550 men, is sufficient to give
any large concern like this a great advantage over its competitors.

The time consumed in discharging coke from the ovens and
recharging the coal, and quenching and loading the coke into cars,
is estimated, under favorable conditions, to require for each oven
about 2£ minutes. The coke, as it is discharged from the ovens, drops
into an immense cage capable of holding 13 tons of coke, the cage
itself weighing 6 tons. This is picked up by a traveling crane
operated on an elevated railway, and run to a tank of water in
which it is immersed for about 15 seconds. It is then lifted out,
and by the time the cage is swung round over a car, the internal
heat in the coke has so driven out all the moisture that the coke
is much drier than when quenched with hose in the old and tedious
way. To see this cage with its load handled by this machinery
one would think it had but a feather's weight.

An advantage in handling coke in this manner is that there is
no waste in the form of breeze, as in the case of the beehive ovens,
where it has to be pried out with bars, and consequently broken
up considerably.

The coke pusher is an admirable piece of machinery, and was
designed by W. B. Hasbrouck, who at present has charge of the
Lowe coke-oven construction work, while W. Larramie Jones, of
the Jones & Laughlin Steel Company, was, I believe, the origi-
nator of the new method of handling and quenching the coke by
machinery. It is certain that they are taking a great interest in
this new system, and it will not be surprising if in time it will
supersede, not only all their beehive coke ovens, but the entire
coke-making systems the world over.

Beehive By-Product Oven. — During the past few years efforts
have been made to use the beehive, or round, coke oven in the
saving of by-products. The results thus far have not been assuring.
Some of them have exhibited considerable ingenuity, but the
section of this oven is not the true form of a retort It is undoubt-
edly much more economical in first cost than any of the standard

312 TREATISE ON COKE

retort ovens with by-product-saving attachments; but it cannot
secure as good results along this line as do the standard retort
coke ovens. It is evident, however, that the coke produced in
this round oven will inherit a much more desirable physical struc-
ture in its coke than that of any of the narrow retort coke-oven
products.

Fig. 32 shows the method of construction of these round by-
product-saving coke ovens.

Doctor Otto builds these ovens at his own expense, runs them
for 12 years, taking the coal from the mines and delivering the
coke to the mine company, for the yield of tar and ammonia, and
at the end of the term surrenders the whole plant to the mine
owners. He must make in this time, from the value of the
products alone, the cost of the ovens, the interest of the capital
invested, and the legitimate profit of a manufacturer, and he is
successful in doing it.

MANUFACTURE OF COKE FROM COMPRESSED FUEL*

It will probably be admitted that the best coking coals on the
continent, and also those of Great Britain, have for years past
been getting scarcer, and various devices have been employed to
improve the quality of the result in coke when made from inferior
seams. A few years ago several works, chiefly in the Saarbrticken
district, came under the author's notice, where a systematic
attempt was being made to improve the quality of the coke by
compressing the fuel before coking, and he was so impressed with
the improved results obtained with poor coking fuels that he
undertook experiments on the same lines. It is proposed in this
paper to embody a short account of the results of these experi-
ments and the benefits derived. It may be said at once that the
result of the trials made showed that the advantages of compression
were by no means confined to the poorest coking fuels.

The idea of compressing fuel for coking purposes originated on
the continent, where many of the coals coked so indifferently that
it was of the greatest importance to adopt any method that gave
a prospect of improving the quality of the resulting coke. It had
been observed that the coke produced from the lower portions of
retort ovens, compressed by the weight of the superincumbent
fuel, was superior to that produced from the upper portions of
the charge, and this led to experiments in compressing the fuel by
various means: first, by stamping in the oven by hand; in other
cases by weighting the charge ; and from this the practice of com-
pressing in a box outside the ovens was gradually evolved, the
stamped cake being afterwards moved out of the box into the
oven by mechanical means.

*By John H. Darby, Journal Iron and Steel Institute, Vol. 1, 1902,
page 26.

TREATISE ON COKE

313

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314 TREATISE ON COKE

A number of samples taken from coking fuels in various parts
of Great Britain were experimented with. The degree to which
slack may be compressed varies with its character, state of divi-
sion, contents of moisture, and other conditions; and, generally
speaking, it was found that the weight of a given bulk of com-
pressed fuel in an oven was 50 per cent, greater than fuel charged
in the ordinary way through the holes in the upper portion of the
oven and leveled by hand. Taking into account the side clear-
ance that has to be allowed in introducing a cake of fuel into an
oven, the net gain in weight that an oven of given capacity would
hold varied from 25 to 30 per cent, in favor of compressed fuel.
But it was found that the compressed fuel coked more slowly
than the uncompressed, and the net gain in production of coke
per oven finally amounted to between 10 and 12 per cent, in favor
of the compressed charge.

To ascertain the difference in the character of the coke from
compressed fuel compared with uncompressed, the weight of a
cubic foot from a solid lump of coke was estimated, and it was
found, in the case of three samples of fuel from Durham, that the
average weight per cubic foot for uncompressed coke was 63.37
pounds and for compressed, 80.88 pounds; for North Welsh uncom-
pressed coke the average weight was 50 pounds per cubic foot,
compressed, 60.57 pounds; South Yorkshire uncompressed coke,
53.9 pounds, compressed, 57.9 pounds; West Lancashire uncom-
pressed, 58 pounds, compressed, 66.4 pounds. It will be seen
that compressed coke is considerably denser, in addition to which
the following advantages were noted: (1) The breeze or small
coke was very much reduced in quantity, the lumps of coke were
larger and firmer and in a marked degree bore handling without
very much breakage. (2) The process of charging an oven by the
mechanical means in use, where compression of fuel is adopted,
occupies much less time than the old method of charging by hand
through holes in the top of the oven; in fact, the time is reduced
from 10 or 12 minutes to 3 or 4 minutes, so that the objectionable
smoke is largely prevented and the loss of by-products is less; in
fact, in some cases, the yield of ammonia has been increased 25
per cent. (3) Less hand labor is employed, and the laborious work
of forcing the wet fuel out of the tubs into the ovens and leveling
the charge in the ovens is entirely abolished, while the clearance
between the cake of fuel and the side of the oven allows the free
escape of the gases and tends to prevent undue deterioration of
the oven walls.

The results obtained show that the quality of the coke is dis-
tinctly improved by compression. Such improvement is natu-
rally more marked in some fuels than in others ; but from a large
number of trials made with many of the English fuels, the writer
is able to say that he has not seen any instance in which the improve-
ment made by compression has not been apparent. Indeed, he is

TREATISE ON COKE 315

aware of a case in which compressed coke is being sold in the open
market at a substantial advance on coke previously made from
similar uncompressed fuel. Even with the best coking fuels the
results obtained seem to justify the outlay in equipping a plant
for compressed fuel, as well as the special case in which it is essen-
tial that the fuel should be compressed in order to produce a mar-
ketable coke.

In reference to the apparatus employed, it is unnecessary to
mention the machine in which stamping is done by hand, or to
describe the earlier forms of mechanical stamps in use, and it will
be sufficient to illustrate two of the later types.

The essential parts of the appliances used are the stamping
machines and compression boxes. These can be combined in a
variety of ways as the surroundings may demand. For example,
there are the combinations, first, of a compression box and charger,
built with a superstructure carrying the stamping machine; sec-
ondly, a compression box and charger with stationary stamping
machine. The first combination may be described generally as
suitable where the machine has to travel for a considerable dis-
tance and take its supply of slack for compression at a number of
stopping places, stamping operations proceeding during the travel-
ing of the machine. The second combination, having a fixed point
for the fuel supply, allows of the application of a fuel-feeding
device as presently described, and offers opportunities for saving
both time and labor. In fact, under favorable conditions, this type
of machine will compress and charge fifty ovens per 24 hours, and
it is probable that this is not the limit of the modern machines.
With both these types of machines, in many instances, a coke-
discharging arm may be conveniently combined with the compres-
sion box, in which case two men are able to control the operations
of pushing the coke out of the oven and charging it with com-
pressed fuel.

NOTE. — If the principles submitted in Chapter VII are correct, that is,
that the calorific energy of blast-furnace fuels is in proportion to the extent
of surface presented to the action of the oxidation gases in the zone of
combustion in the blast furnace, and as it has been demonstrated that the
most dense fuel — anthracite — is the lowest in value for rapid heat giving
it follows that, if a vigorous fuel is a desideratum for use in a blast fur-
nace, then any element of compression in the charge of coal, tending to
densify the coke, or in any way to render it more like anthracite, should
be avoided. — ED.

CHARGING AND COKE-PUSHING MACHINERY

The following description of coke pushers and ramming machines
is taken from articles by Alfred Ernst and Dr. W. B. Rothberg,
describing the by-product coke plant of the Lackawanna Iron and
Steel Company, at Lebanon, Pennsylvania, appearing in Mines
and Minerals, March, 1904.

316

TREATISE ON COKE

Coal-Ramming or Compacting Machines. — Eight coal-ramming
machines K, Fig. 33, are used at this plant, consisting of ham-
mers working in steel guides, and actuated by means of an electric
motor. The rammers are supported on the framework of the coal
bin, in which a sufficient allowance is made for strain due to same.
The rammers can be operated in any desired height without chan-
ging the stroke of the machine. A controller of sufficient capacity
is placed in a convenient position for the operator.

FIG. 33. COAL BIN AND RAMMERS

Coal-Charging Boxes. — Four coal-charging boxes B, Fig. 34,
are provided, each of which consists of a base plate or peel, resting
on rollers, having a rack attached thereto, and engaging with
suitable pinions and gearing for moving the peel into the oven
with a cake of compressed coal. The sides and ends of the box
are of sufficient height to form a cake of coal for the ovens. The

TREATISE ON COKE

317

318 TREATISE ON COKE

front end, or end nearest the ovens, is formed of two doors with
a suitable locking device connected directly to the operator's cab
by means of locking levers. The rear end is stationary and is built
up rigidly on the lower framework of the machine. The sides of
the box are supported by short links, with pin joints, attached to
side posts, which form part of the solid framework of the machine.
To the lower corner of the rear end of each side plate is fastened a
pin and roller that engages with a cam on either side of the peel.
After the box has been filled and rammed, it is placed on the
pusher platform D and moved to the oven. When the oven has
been emptied and the coal box brought into position, the front
door of the box is opened from the cab, and the peel set in motion.
This starts the peel toward the oven, pushing forwards on the
sides, causing them to rotate about their several points of support,
thus relieving the cake of coal from any side pressure. The coal
is then placed in the oven on the peel and the doors closed. The
door on the end of the oven nearest the coal box is lowered to the
peel and the peel withdrawn, leaving the cake of compressed coal
in the oven. The cams on the peel on their return engage with
the pins on the rear end of the side plates, and draw them into
their original position, locking them. The front doors are then
closed and the coal box returned to the ramming station for a
fresh charge. The machine is mounted on heavy trucks that are
driven by a 50-horsepower electric motor, which also operates the
peel. By means of these trucks and motor, the box is run under-
neath the bin to receive its charge, or back on to the platform of
the coke pusher. The box is held on the pusher by rail clamps
operated from the cab.

Coke Pusher. — The two coke pushers at this plant are operated
as follows: The coke is pushed from the ovens by means of a
heavy ram F, Fig. 34, carrying a cast-steel rack that is driven by
a pinion, connected by means of suitable gearing to a 50-horse-
power electric motor. This ram is guided by means of rollers, a
sufficient number being used to hold it properly in place. On the
framework of this machine are also provided tracks for a coal-
charging box. The whole mechanism is carried on a massive steel
framework D resting on four track wheels that are connected by
means of suitable gearing and clutches to the 50-horsepower motor
used to operate the ram.

Situated on this steel framework in a convenient position is
the operator's cab, built up of steel framework and covered with
corrugated galvanized iron, and also containing a sufficient number
of windows to allow the operator a good view of all the operations
of the machine. The operator's cab contains the controllers, etc.
for all the operations of this machine, which are as follows: The
pusher is run along the tracks parallel to the line of coke ovens,
until the tracks on the pusher platform are directly opposite those

TREATISE ON COKE

319

from the coal bin. The coal-charging box is run on to the pusher
platform and clamped there by means of rail clamps on the coal box.
The whole machine is then moved to a position in front of the oven

to be drawn. The clutch connecting the motor with the pinion dri-
ving the ram is engaged and the coke pushed out of the oven. The
coal-charging box is then placed in front of oven as described above.

320 TREATISE ON COKE

For carrying the boxes underneath the bins and rammers,
four platforms and tracks are provided. These platforms consist
of a steel framework supported on columns and carrying a plate
floor, resting on beams, and also two lines of rails, forming tracks
for the charging boxes to pass backwards and forwards underneath
the rammers when the coal is being compacted. The platform
has a factor of safety of six, on account of vibration during the
process of compacting.

Details of the construction of the coal-charging box and coke
pusher are shown in Fig. 35.

PLANT FOR SAVING COKE BY-PRODUCTS*

The Extension of the Coal- Distillation Plant at the Matthias
Stinnes Mine in Carnap, Germany. — The following is taken from
an article by Doctor Bertelsmann appearing in the Zeitschrift fur
Berg-Hiitten und Salinenwesen for 1901, page 481:

At the Matthias Stinnes bituminous coal mines there have
hitherto been but thirty coke ovens; these were of the under-fired
type and were arranged to recover the tar and ammonia from the
gas, which was used exclusively for heating the ovens. During
the 4 years in which they have been in operation, a series of tests
were carried out in order to obtain exact data on the following
points: (1) how to obtain the best coke from a high volatile
bituminous coal; (2) how to obtain the largest amount of surplus
gas of high calorific and candlepower, fit for illuminating and
power purposes; (3) what by-products can be recovered from the
gas, in what quantities, and into what form can they be most
profitably worked up.

The results of these tests afforded the data in accordance with
which the extension of the existing plant was laid out. They were
as follows: (1) a coal-mixing plant; (2) thirty-five coke ovens,
with gas producers, reversing gear and regenerators, apparatus
for the separation of the coke-oven gas, also pushing and charging
machines and coal-compressing apparatus; (3) condensing plant
for washing the gas and recovering the by-products; (4) an
ammonia plant; (5) a benzol plant; (6) a cyanide plant; (7) an
office building, with eating hall and bathrooms. With the excep-
tion of the cyanide plant, the above are either completed or in
process of erection and will be hereafter described. A description
of the cyanide plant cannot be given, as the details are as yet
undecided.

Coal-Mixing Plant. — The coke made from a high volatile coal,
in consequence of its coarse-grained structure and the large amount
of the evolved gas, is very porous, brittle, and apt to be full of
cracks and therefore ill adapted to stand the burden in the blast

*Mines and Minerals, December, 1902, page 214.

TREATISE ON COKE 321

furnace. It may be improved by crushing the coal and pressing
it into a solid cake before charging into the oven. Tests were made
to ascertain whether a mixture of different coals would improve
the coke, and it was found that, with the addition of from 10 to
20 per cent, (weicher staubiger Kohle) lean, dry coal, the strength
and density of the coke were notably increased. In order to do
this on a large scale, the coal-mixing plant was installed. The
coking coal, coming direct from the mines to the washer, and
drained of most of its water in the storage bins, is brought to the
plant by a chain conveyer, while the outside coal is brought in
by rail and unloaded by hand. The two kinds of coal are elevated
to separate hoppers, of which there are four, placed on the four
corners of a square. Each hopper ends in a conical spout, which
is provided at its lower end with a loose sleeve, adjustable verti-
cally. Beneath these spouts is a horizontal mixing table that
revolves about a central vertical axis. As the adjustable sleeves
are raised, a certain amount of the coal runs out of the spouts on
to the moving table, and is scraped from there by an adjustable
arm into a mixing screw. The proportion of each coal in the
mixture is controlled by the adjustable sleeve and scraping arm.
The screw discharges to a disintegrator, which still further mixes
and crushes the coal, and it is then elevated to two large coal
hoppers above the ovens. Power for the mixing plant is furnished
by a single-cylinder steam engine.

Ovens. — As already stated, it was desired to select an oven
system that would afford the largest possible amount of surplus
gas, this gas to be suitable for use in gas engines at the adjoining
coal mines. For this reason it was inevitable that a return should
be made to the method of recovering the heat of the chimney
gases by means of the regenerative system. The newly constructed
ovens are thirty-five in number and of the double-wall type with
vertical flues, each flue being separately heated, and connected with
the other flues only by the common off-head canal. Canals and
pipes laid beneath the coke platform bring the heated air and the
gas to their respective canals, lying beneath the oven floor and
the heating flues, each serving for the two oven walls. From these
canals the air and gas are admitted to each separate vertical heat-
ing flue. As insufficient air is admitted, only a partial combustion
ensues, in order to avoid local overheating, complete combustion
taking place on the entrance of additional air, entering at a point
in the middle of each heating flue. The burned gases from all the
flues pass to a common horizontal canal above and descend from
this through three vertical off-head flues to the chimney canal,
on the pusher side of the ovens. The admission of the primary
and secondary air and the gas is regulated for each two walls, and
the draft opening to the chimney canal for each wall by dampers.
The heated gases from all the ovens pass through a reversing
valve to one of two regenerators, where the heat is absorbed by

322 TREATISE ON COKE

checkerwork, passing thence through a second smaller reversing
apparatus to the stack. The air for combustion is forced through
the other regenerator in the reverse direction by a motor-driven fan
placed at the small reversing valve, is heated by the checkerwork,
and passes through the large reversing valve to the before-men-
tioned air canal. At the end of each reversal period, the valves
are moved 120° and the regenerators interchange their functions.
The charging of the coking chamber can be done through the
customary openings above, but consists usually in pushing the
cake of compressed coal into the oven from the pusher side. For
this purpose an electrically driven charging machine, having two
stamping boxes, is used. Over each box is an electrically driven
stamper. The coal to be stamped can be delivered to the boxes
at any point along the battery by overhead conveyers.

Each oven is provided with a riser pipe in the middle to con-
duct away the gas. These risers connect with two U-shaped
mains, and are on each side for the rich and poor gas respectively.
The connection to these mains is made by movable valves dipping
into a seal to make them gas-tight. The rich gas is given off only
during the first part of the coking time, the remainder being
classed poor gas. Separate pipes take the two gases to the con-
densing house, there being a tar drain from each to a common
reservoir.

Condensing Plant. — In accordance with the plan of handling
two qualities of gas, the condensing plant consists of two identical,
but entirely distinct, systems. The gases coming hot from the
oven pass first through high annular air coolers, then to rectangu-
lar water coolers, leaving them at atmospheric temperature.
They are then forced by exhausters into the tar scrubber, then to
a series of rotating slat washers, one after the other. In these,
the ammonia, benzol, and cyanide are absorbed by suitable liquids,
the sulphureted hydrogen being removed from the rich gas as
well. This completes the washing process, the gases passing
directly to where they are used, as already described. The air
coolers, as has been stated, are annular in form, that is to say,
having an inner air-shaft so that the air-cooling effect takes place
from both sides at once. All the coolers are divided by partition
walls so that the inlets and outlets are at the bottom, allowing
several coolers to be connected with little space between, thus
avoiding long pipe connections and one-sided loads on the cooler
shells. The water-tube coolers are so arranged that the gas and
water pass through in opposite directions. The warm water
passes under its own pressure to an open cooler of wooden lattice-
work, when it is cooled by evaporation, and is raised from a col-
lecting basin to the elevated tank over the water coolers by rotary
pumps, to be used again. The tar and ammoniacal liquor con-
densed in the coolers is led to a gravity separating tank and is
carried by pumps to be worked up.

TREATISE ON COKE 323

Each of the nine rotating slat washers consists of a large cast-
iron drum having an outside flange near each end, traveling on
two pair of grooved rollers, which drive it by friction. The entrance
and exit of the gas is through stufhngboxes. The drum is divided
by thin cast-iron partitions having a central opening into four
equal chambers, each being again divided by a wooden partition,
so that communication is along the periphery only. The space in
the chambers is then filled with closely fitting gratings of wood.
The washing liquid enters and leaves through stuffingboxes at
either end, the direction of its passage being opposed to that of
the gas. The upper half of the washer is, therefore, always filled
with gas and the lower part with wash liquor, both moving in
opposite directions, and, by the rotation of the drum, the gas is
forced to pass continually over freshly wetted and dripping surfaces,
so that an intimate contact between gas and liquid is assured.
No gate valves are employed on the gas mains and by-passes, seal
pots with dip pipes or partitions being used, which can be made
gas-tight at any time by filling with water.

The motive power for the condensing house is supplied by
two single-cylinder steam engines with poppet valves, used alter-
nately. These drive the apparatus already mentioned, and, in
addition, six horizontal piston pumps for circulating the waste
liquors, a gas compressor, and two dynamos for light and power
purposes.

Ammonia Plant. — The ammonia is removed by washing the
gas with water after it has been freed of tar. The liquor from the
washers and the condensate from the coolers are collected in one
reservoir and raised by a piston pump to an elevated tank, from
which the mixture flows by gravity to the ammonia house. In
order to obtain ammonia in a salable form it must first of all be
separated from the liquor and to some extent purified. This
process may be divided into four parts: (a) the preheating of
the liquor; (6) the driving off of the carbonic acid and the
sulphureted hydrogen; (c) the driving off of the free ammonia;
(d) the driving off of the fixed ammonia.

(a) The preheating of the liquor is done in an apparatus in
which a part of the water that has given up its free ammonia is
used to heat the raw ammonia liquor. The apparatus consists of
a series of cast-iron chambers placed one above the other, and
divided by thin steel plates, the first, third, fifth, etc., and the
second, fourth, sixth, etc., being connected, so that two entirely
separate circulation systems of alternate raw liquor and hot water
are formed. The flow is in opposite directions, the transmission of
heat being through the partitions.

(6) The liquor, thus warmed, passes upwards under pressure
and flows down through a small column. In this it encounters a
current of fresh steam, or of escaping steam from the apparatus
below, described later, which in either case is sufficient to drive

324 TREATISE ON COKE

off the carbonic acid and sulphureted hydrogen, but not the
ammonia. The gases so driven off are returned to the unwashed
oven gas.

(c) The partially purified water now comes to the upper por-
tion of the large column apparatus. As it passes downwards
through the latter, it encounters enough steam to free it of all its
volatile ammonia. A part of the heated water is then removed to
pass through the before-mentioned preheater, to warm the raw
liquor, and after serving this purpose is used again in the slat
washer for condensing purposes. In this way the incrustation of
the washer slats with scale, which is generally the result of
constantly using spring or river water, is avoided.

(d) The liquor passing down through the column enters the
lime chamber by a seal pipe and is then mixed with milk of lime,
forced into the chamber by a pump. Passing thence to the lower
part of the column it encounters fresh steam and is deprived of
the ammonia set free by the lime. The waste liquor, now free of
ammonia, is allowed to settle in the lime tanks and runs to waste.

The ammonia thus obtained in gaseous form is still mixed with
a good deal of steam, and can easily be transformed into ammonium
sulphate or strong ammonia liquor, as desired. The manufacture
of aqua and liquefied anhydrous ammonia is also contemplated.

In making ammonium sulphate, elevated lead-lined wooden
boxes, reenforced with iron and set above the floor, are used.
The arched lid is of cast iron, lead covered, and carries a number
of lead-covered connections that allow ammonia vapor, acid, and
mother liquor to be introduced and the waste vapors to escape.
The ammonia vapors are admitted through dip pipes, beneath
circular toothed hoods, allowing an intimate contact between
vapor and liquid. The vapors given off escape through one of the
connections to a condenser overhead, the baffles in which catch
and hold any entrained liquid, and pass thence to the foul-gas
main. The bottom of the box slopes from all sides toward the
middle and is furnished with an opening, closed by a hard-lead
cone worked by levers from the outside. Under each saturating
box is a lead-lined receiver. The operation is as follows : Through
one of the connections certain quantities of 60° sulphuric acid and
mother liquor from the last operation are introduced and saturated
by the passage of ammonia gas. When the saturation is complete,
the contents of the box are run into the vessel below, through the
opening, and then allowed to settle. The clear mother liquor is
drawn off and the salt is dried in a centrifugal separator. The
latter is then ready for market. The mother liquor is drained to
a collecting basin and then raised by a hard-lead injector to an
overhead tank, from which it flows to the saturating boxes again.
If the ammonia vapor is to be worked up into concentrated liquor,
it is deprived of a certain portion of its water in a return-flow
condenser and then entirely cooled, the finally condensed strong

TREATISE ON COKE 325

liquor being drawn off and marketed in that form. The floor and
walls of the ammonia house are covered with asphalt, so as to resist
the action of the acid and mother liquor.

Benzol Plant. — The benzol and its homologues are absorbed
from the gas by washing it with dead oil in one of the rotary slat
washers already described, the saturated oil being pumped to the
benzol plant. Here it flows first through preheaters, like those
in the ammonia works, supplied with hot dead oil from the other
apparatus. From the preheater it comes to the column apparatus,
and passing downwards through this is exposed to the action of
ascending steam and is deprived of its benzol, etc. The action of
the steam is enhanced by arranging the columns in a circle about
a central shaft, from which they are all directly heated by gas.
The oil leaving the column serves, as already stated, to preheat
the incoming oil, is then entirely cooled in water coolers, and passes
again to the gas washer. The vapors recovered from the oil in
this process consist of water and benzol hydrocarbons. After con-
densing, they are separated into water and raw benzol and the
latter collected in a tank. From this it is redistilled by means of
a still provided with column and returns condenser, so operated,
first with indirect and then with direct steam and by regulating
the condenser, as to deliver 90-per-cent. or 50-per-cent. or other
degree benzol, as desired. The separate fractions are run into
separate receivers and pass thence to the storage reservoirs. It is
also intended to install apparatus for rectification with sulphuric
acid, and further fractional distillation.

CHAPTER VII

PHYSICAL PROPERTIES OF CHARCOAL, ANTHRACITE, AND

COKE, AND A COMPARISON OF BEEHIVE AND

BY-PRODUCT COKE

The law of progress is universal. Beginning with the blade,
then the ear, and ultimately the full corn in the ear. The iron
manufacturers have studied, under many years of practical expe-
rience, the properties and values of the principal fuels in general
use for iron smelting — charcoal, anthracite, and coke.

The following table, from J. M. Swank's "Iron in All Ages,"
will exhibit in a very interesting way the struggle of these fuels
for supremacy, with their present ranks, the coke leading all others:

TABLE I

Years

Charcoal
Net Tons

Anthracite
and Coke

Coke
Net Tons

Remarks

Net Tons

1854

342,298

339,435

54,485

1855

339,922

381,866

62,390

Anthracite leads charcoal

1869

392,150

971,150

553,341

Coke leads charcoal

1875

410,990

908,046

947,545

Coke leads anthracite

1880

703,522

2,448,781

7,154,725

Era of coke

1900

339,874

1,636,366

11,727,712

Era of coke

1901

360,147

1,668,808

13,782,386

Era of coke

1902

378,504

1,096,040

16,315,891

Era of coke

This exhibit establishes the fact that the use of coke in smelt-
ing iron is largely on the increase, and that the use of anthracite
is decreasing, especially when used alone in blast furnaces; while
charcoal, in its limited use, appears to be nearly stationary.

As coke is now the chief fuel in the metallurgy of iron and steel,
and its use is steadily increasing, it is evident that it is destined to
maintain its prominent place of usefulness in the coming ages,
increasing in largest proportion with the expansion of the manu-
facture of iron and steel.

The table also shows that coke has superseded anthracite in
blast-furnace operations. Where the relative cost of coke to

326

TREATISE ON COKE

327

anthracite does not largely exceed 25 to 30 per cent., the former
fuel would probably obtain the preference, from its greater calorific
energy in the production of a larger output of pig iron in the
furnace.

At present, furnaces within the borders of the economic bounds
of coke are using this fuel mainly and obtaining supplies from
the Connellsville, Alleghany, and Clearfield regions.

Mixtures of coke with anthracite are made at some furnaces,
ranging from one-eighth to one-half of the fuel charge. It is
evident, however, that the use of coke in blast furnaces is steadily
on the increase and will continue to enlarge the bounds of its
usefulness, displacing the less energetic anthracite fuel.

From the limited area of the chief anthracite fields in the East,
containing in the aggregate only 488 square miles of coal measures,
and from its present large annual output of 53,967,543 net tons
in 1893, with a deeper and increasing cost of mining, it cannot
long profitably continue to supply furnace fuel at very low rates.

The charcoal fuel for blast-furnace use, under the rapid cutting
down of the primeval forests, must continue to afford only a lim-
ited supply and its use be confined to the smelting of pig metal
for special purposes.

From all the foregoing it will be seen that the present and
future manufacture of coke demands and should receive increased
and earnest attention.

The following table exhibits the decrease and increase of the
use of the fuels used in blast-furnace operations, in detail:*

TABLE II

Fuel Used
Gross Tons

1898

1899

1900

1901

1902

Bituminous,

chiefly coke

10,273,911

11,736,385

11,727,712

13,782,386

16,315,891

Anthracite

and coke . .
Anthracite

1,180,999

1,558,521

1,636,366

1,668,808

1,096,040

alone

22,274

41,031

40,682

43,719

19,207

Charcoal. . . .
Charcoal and

296,750

284,766

339,874

360,147

378,504

coke

44,608

23,294

11,665

Totals....

11,773,934

13,620,703

13,789,242

15,878,354

17,821,307

This table shows in a very emphatic manner that coke is the
principal fuel now in use in blast-furnace and other metallurgical
operations, and that anthracite alone holds a small and vanishing
place in these great industries.

*From statistical tables by James M. Swank, general manager
American Iron and Steel Association, 1903.

328

TREATISE ON COKE

Charcoal, in use mainly for special purposes, maintains its
small place among these fuels.

In these fuels, especially for blast-furnace and kindred uses,
the prime requisites are hardness of body, to sustain the weight
of furnace charges, to resist dissolution in the upper portion of the
furnace, and full cellular structure to afford combustion with the
utmost energy at the proper zone in the furnace. These elements
in the fuels are essential in the economical and vigorous working
of the furnace.

Charcoal was, in the early times of iron making, the principal,
if not the only fuel used in forges and blast furnaces. From its
softness of body it could only be used in the old-time forges and
low furnaces with feeble blast in the initial operations of iron
smelting. It was the educating fuel in the early operations of
iron smelting and iron working.

Anthracite is a natural coke. From its hardness of body it
is abundantly able to sustain the pressure of the highest furnace
charges, as well as to resist the dissolving action of hot carbon-
dioxide gas, but its extreme density of physical structure renders
its combustion slow, and its calorific energy moderate.

Between these extremes of blast-furnace fuels, coke comes to
the iron manufacturer inheriting in harmonious combination the
good properties of charcoal and anthracite. It has hardness of
body to sustain the burden of the highest furnace, and this hard-
ness enables it to resist dissolution in its passage down the furnace
to the zone of combustion. Its large surface space from its cellu-
lar structure affords full preparation before reaching the zone of
fusion, which assures great calorific energy in its combustion.

Beginning with 1850, the three fuels at the service of the iron
manufacturer consisted of wood charcoal, anthracite, and coke.
These are composed as follows:

TABLE III

Fuel

Moisture
Per Cent.

Volatile
Matter
Per Cent.

Fixed
Carbon
Per Cent.

Ash
Per Cent.

Sulphur
Per Cent.

Phos-
phorus
Per Cent.

Charcoal

3.50

6.490

87.00

3.00

020

Anthracite

2 50

4 000

87 00

6 00

020

Coke . .

.49

Oil

87 46

11 32

029

It required time to assure furnace managers of the special fuel
best adapted for their use, considering cost, energy of fuel, and
quality of pig iron made.

During the past two decades the examination of furnace fuels
embraced not only their chemical constituents, but also their phys-
ical properties. This has led to the conclusion that the physical
structure is a very important factor in conferring energy in the

TREATISE ON COKE 329

combustion of the fuel. Rapid combustion in the furnace results
in increased output with corresponding reduction of cost of pig iron.

This intelligent study of the physical as well as the chemical
properties of these fuels in furnace use did not end here; but the
correlated study of the form and size of the furnace, the heat and
pressure of blast, have been put into successful- practice in the
smelting of iron. This has led to the development of the fuel best
adapted to these metallurgical operations, especially in the large
blast furnaces for the production of Bessemer pig iron.

It becomes, therefore, most important to the coke manufac-
turer to consider the essential elements in coke that have con-
ferred on it the most distinguished place in the iron industry, so
as to maintain in its manufacture these desirable properties. If
the physical structure of these fuels is examined, it will be found
that charcoal consists of a series of longitudinal tubes, uniting
with each other and affording ready passage to the furnace gases.
The walls of these tubes are readily oxidized. Charcoal is, there-
fore, a pure and moderately energetic furnace fuel.

Anthracite is a natural coke, made under immense pressure,
and very dense in its physical structure. It inherits no cellular
structure, as it has been fused into a dense vitreous mass by the
pressure and heat under which it was made, this great pressure
repressing the cell development. It is, from its physical structure,
the least energetic of the fuels under consideration. Its action in
a blast furnace is somewhat relieved, as under heat it decrepitates,
and thus increases the extent of surfaces exposed to the oxidizing
gases of the furnace, compensating in a measure for its density.

Coke, on the other side, has a structure made of a series of
irregular, promiscuously disposed cells, with vitreous walls; these
cells are connected by diminutive passages that afford free courses
for the oxidizing gases of the blast furnace. It is these hard vit-
reous cell walls in coke that give it the superior value as an energetic
fuel in blast furnaces.

From the foregoing, it will be evident that the physical struc-
ture of coke, other things being equal, is the main element that
confers on it the superior place it holds among blast-furnace fuels.
The same is true, in a modified way, of charcoal fuel. The anthra-
cite holds the lowest rank.

The factor of the cost of these fuels is also an important element
in determining their use in each locality. This, however, does not
enter into the present investigation, except as a qualifying clause.

PROPERTIES OF COKE

The main inquiry at this place is to determine the nature of
the physical and chemical properties that are most desirable in
coke for blast-furnace use, and to meet, as far as possible, these
requirements in the manufacture of coke. These requirements in

330

TREATISE ON COKE

coke fuel are clearly defined under five distinct elements in its
manufacture: hardness of body; fully developed cell structure;
purity; uniform quality of coke; and coherence in handling.

In the further consideration of these valuable properties in
metallurgical coke, it may be helpful to the -manufacturer to con-
sider these five essentials in detail.

Hardness of Body. — The best cokes possess a hardness of body
of 2 to 3 per cent. . By this is meant hardness of body or cell
walls, not density, for dense cokes are usually soft or punky;
while hard-bodied cokes are generally well developed in cellular
structure. These two physical properties, hardness of body of
coke and full cell spaces, are correlated, just as softness of body
and density are associated.

The coal from which soft coke is made lacks the element that
fuses and hardens and is therefore deficient in these prime essen-
tial qualities. The nature of this fusing element or elements in
coking coals has not been clearly defined, at least such information
has not come under the notice of the writer.

The following table of careful tests of hardness of body and
development of cells will prove interesting:

TABLE IV

Locality

Grams
in 1 Cubic
Inch

Pounds
in 1 Cubic
Foot

Percentage
by
Volume

V Compressive Strength I
§ Per Cubic Inch,
3 One-Fourth Ultimate
£• Strength

ITJ Height of Furnace
g Charge, Supported
«* Without Crushing

«H
rt

CJ.

Hardness
Per Cent.

Dry

Wet

Dry

Wet

Coke

.Cells

Standard Coke
Connellsville

12.14
15.02
13.02

21.34
23.41
22.41

46.30
57.20
49.03

81.25
89.20
85.37

43.73
47.68
41.82

56.27
52.32
58.18

236
340
246

94
136
97

i
i
i

3.0
2.6
2.3

1.69
1.91
1.90

Syracuse, New York ..
Morris Run, Pa

NOTE. — The Connellsville coal was coked in beehive ovens. Morris Run
coal, Tioga County, Pennsylvania, was coked in Semet-Solvay ovens, at
Syracuse, New York, and the same quality of Morris Run coal was coked
in beehive coke ovens near the mines.

In the treatment of dry coals, the hardness of the body of the
coke can be increased by coking such coal in the narrow or retort
coke ovens. The cell structure in this kind of oven is always
more or less depressed as compared with the full cellular develop-
ment in coke made in the beehive class of oven.

In any type of oven, maximum heat is required to produce
the hardest-bodied coke, but it is not conducive to the largest
output of by-products.

TREATISE ON COKE 331

The solution of this question, the elements in coal that con-
tribute to its fusion in a coke oven and assure hardness of body
with large cell spaces, is most important; for, if they were known,
equivalent elements could be supplied to coals deficient in
them, thus improving the quality of coke in its most essential
requirements.

This prime necessity of hardness of the body of coke will be
evident when the conditions of its combustion in a blast furnace
are considered. In its movement down the furnace to a short
distance above the tuyeres, it is enveloped in the ascending cur-
rents of hot gases, mainly carbon dioxide; this gas possesses the
power of dissolving carbon or coke, and is especially destructive
to the soft variety.

Sir I. Lowthian Bell, in his treatise on the "Manufacture of
Iron and Steel," page 287, gives the following:

Hard coke, soft coke, and charcoal pounded as nearly as
possible to the same size were placed in a hard-glass tube, which
they filled, and were then raised to a good', red heat in a Hoff-
man double furnace. During the space of 30 minutes, 800 cubic
centimeters of carefully dried carbonic acid was passed over
each specimen. The issuing gases had the following volumetric
composition :

HARD COKE SOFT COKE CHARCOAL

PER CENT. PER CENT. PER CENT.

Carbonic acid 94.56 69.81 35.20

Carbonic oxide 5 . 44 30 . 1 9 64 . 80

100.00 100.00 100.00

It will thus be evident that every pound of coke dissolved by
this gas, before reaching the efficient zone of combustion, is a
double loss, reducing the heat of the furnace and disarranging its
regular operations.

It is evident that an equal amount of fixed carbon in these
three principal fuels, used in blast-furnace operations, will afford
equal volumes in heat units; but it is also evident that the time
required to produce these heat units will be in proportion to the
extent of surface exposed to the oxidation gases in the blast
furnace or similar heating operations. A pertinent example has
been witnessed in the old-time "back-log." It contained a cer-
tain number of heat units, but they came out very slowly. It
was mainly designed to "hold fire," but when energetic heat was
required the log had to be split into small pieces to afford a greatly
enlarged surface to the oxidation agency in its combustion. This
foundation principle holds practically true in the combustion of
these fuels, the anthracite representing the "back log"; the char-
coal and coke, the rapid-burning fire in front of the "back log."

It follows, therefore, that in all coking operations any element
in the plan of the chamber of the oven that restrains the liberty

332

TREATISE ON COKE

of the coal in its fusing to make fully developed cells, reduces in
such proportion the energy of the fuel; in other words, every
approach to the dense anthracite structure is inimical to the value
of the fuel for rapid and energetic combustion. This principle,
not generally well developed, is one of the chief elements that has
held the product of the round or beehive coke oven in such accept-
ance with blast-furnace managers, and enabled it to maintain its
place of usefulness in the presence of criticism and sarcasm as to
its wastefulness and antiquated condition.

It will be seen from the tabulated statements that, at the close
of the year 1902, there were 69,069 beehive coke ovens in operation
in the United States, against 1,663 retort ovens of all forms.

Well-Developed Cell Structure.— The coals best adapted for
coke making will usually afford, in conjunction, ample cellular
development and hardness of body. The value of full cell struc-
ture in coke will be readily appreciated when it is considered that
such fuel presents the largest surface for pxidation in a blast fur-
nace. The desirable ratio of cellular space to the cell walls or
body of the coke has been carefully determined, and found to be
as 44 to 56, nearly. That is, the cubic contents of coke body to
cell space is as 43.73 per cent, of coke to 56.27 per cent, of cells.

The evidence, by filling these cell spaces with water under the
receiver of an air pump, clearly shows the thorough connections
by passages of all the cells in the coke. The calorific energy of
the coke fuel in the crucible of a blast furnace also shows how easily
and thoroughly the blast penetrates these cell spaces and main-
tains rapid combustion.

TABLE V

Grams in
1 Cubic
Inch

Pounds in
1 Cubic
Foot

Percentage
by Volume

2 Strength
c Inch,
Ultimate
gth

Furnace
ipported
Crushing

M 4*

Locality

•a-St £

IT0-?

O o

-§0

&&"

•5&!

W &

Dry

Wet

Dry

Wet

Coke

Cells

go, i
8 o

£&

Pounds

Feet

Standard Coke

(a) Connellsville

12.51

21.62

47.69

82.20

43.93

56.07

301

110

3.0

1.74

(b) Otto-Hoffman oven

14.64

21.02

55.79

80.07

61.13

38.87

465

186

3.1

1 80

20.49

24.23

78.07

92.30

77.22

22.78

940

376

3.5

1.82

NOTE. — (a) Coke made from Connellsville coal in beehive ovens;
(b) coke from sides of Otto-Hoffman oven, from Connellsville coal ; (c) coke
from bottom of Otto-Hoffman oven, from Connellsville coal.

It is impossible, however, to make good coke from coal that
is wanting in the elements that assure thorough fusion in the
coke oven. Inferior coking coals can be coked by special oven

TREATISE ON COKE 333

treatment, but the coke from such coal is always of a lower
quality. No condition of oven treatment can make good coke
from bad coking coal.

Table V exhibits, in a marked manner, the repression of cell
development when Connellsville coal has been coked in Otto-
HofTman retort coke ovens, as compared with the structure of
coke made from same quality of Connellsville coal and coked in
the modern beehive coke oven.

In the presence of these facts, in regard to the repression of
cell development in retort coke ovens, it becomes a matter of
great interest to determine whether the increased hardness of body
of the retort-oven coke will compensate in blast-furnace work for
the greatly diminished cell space in this coke. It will require
furnace determinations to adjust the relative loss and gain from
these related physical conditions.

Purity. — Carbon is the source of heat in coke. Other proper-
ties being equal, the larger the percentage of carbon the greater
is the volume of heat. .

As coal has had its genesis in vegetable matter, it usually inherits
3 per cent, to 7 per cent, of ash. A coke, therefore, not greatly
exceeding 10 per cent of ash can be regarded as an average clean
fuel. Cokes inheriting only 5 per cent, to 7 per cent, of ash are
regarded as exceptionally pure.

The sulphur in coke should be under 1 per cent., if the fuel is
to be used in metallurgical operations. The best coke contains
only i to f per cent, of this impurity. Ordinarily, the volume of
sulphur in coal is in a certain proportion to its slate or ash, but
there are exceptions to this relationship where coal high in ash is
quite low in sulphur. The reduction of the slate in coal by wash-
ing or picking generally reduces the percentage of sulphur. About
40 per cent, of it is volatilized in the coke oven.

A reference to Chapter III will show the great progress that
has been accomplished in the last decade in cleaning coal from its
impurities by crushing, classifying, and washing. The manufac-
turer of coke has now all kinds of washers at his service, so that
no valid excuse can be urged to cover the production of impure
coke. But it may be submitted here that, while most coking coals
can be successfully treated in washeries, yet there are some that
cannot be cleaned by the best modern appliances. The excep-
tions, however, are so limited that the coke manufacturer need
not hesitate to submit samplings of his coal for washing tests to
the reliable firms, before noted, for definite determinations in the
capability of the washing process in removing slate, sulphur, and
other impurities from the coal.

Phosphorus is found present in coke. In the purest varieties
it runs from .012 per cent, to .029 per cent. As a general expe-
rience, the phosphorus in the coal goes over to the coke; but there

334 TREATISE ON COKE

are occasional exceptions to this. When coal is washed prepara-
tory to coking, some of the phosphorus goes out in the slates and
refuse.

Uniform Quality of Coke.— The uniform quality of the coke is
one of the important requirements in view of what has been noted
of the destructive action of hot carbon-dioxide gas on the soft
portions of the coke.

The black ends that are sometimes made in coking have to be
included in weighing charges for the blast furnace, and their ready
dissolution reduces the heat power in the proper zone in the fur-
nace. As this defect can be controlled by the manufacturer of
coke, no reasonable defence can be urged for the presence of black
ends in coke made for furnace use.

It has been shown that the use of coke as a metallurgical fuel
is not only quite large, but increasing in the manufacture of iron
and steel. The large number of establishments for the manufac-
ture of coke in the United States assure the truth of the foregoing
statement.

Table VI will show the physical as well as the chemical prop-
erties of American and Mexican cokes. In examining this table
it will readily appear that in the best coke the aggregate of cell
space to body of coke is in the relation of 44 to 56, nearly. It is
not submitted that all coking coals can be made to assure this
ratio of cells to body of coke, but in the coals best adapted
for making good coke, a close approximation to these physical
relations should be found.

Coherence in Handling. — In blast-furnace practice, it has
recently been determined that cokes vary widely in breakage in
handling in the railroad cars and at the furnace, making breeze
that is undesirable, and which, if in large proportion, congests the
furnace, reducing the output. This fine material from brittle coke
is generally thrown aside as worthless. In careful tests recently
made of three principal qualities of blast-furnace cokes, which can
be designated as A, B, and C, 5 tons of average shipments of each
variety were taken just as received in railroad cars at the furnace ;
these classes were carefully separated into large, medium, and breeze.
All these tests were made by volume, with the following results:

ABC
PER CENT. PER CENT. PER CENT.

Large coke... 45.71 56.81 54.40

Medium coke 25.71 40.90 44.00

Breeze 28.58 2.29 1.60

From the above, the great loss in fuel and freight in the breeze
produced from the class A will readily appear. The cokes B
and C vary little in the loss from breeze. But the medium coke
in the class A, from its brittle property, would reduce its value in

eo.te

TAX

FULTON'S TABLE EXHIBITING THE PHYS

REVIS]

Locality

Grams
in 1 Cubic
Inch

Pounds
in 1 Cubic
Foot

Percentage
by Volume

Compressive Strength
Lb. Per Cubic Inch,
1 Ultimate Strength

Ft. Height of Furnace
Charge, Supported
Without Crushing

Order in Cellular

Dry

Wet

Dry

Wet

Coke

Cells

Connellsville — Standard Coke . .

15.47

23.67

59.09

90.28

52.78

47.22

301

149
209
316
181
245
212
213
170

• 933

192
409
274
227
381
327
306
245
326
236
200
90
158
146
231
340
246

804
217
240
316
280
300
431
213
216
250
274
286

296
300

120

1
I

1
1

1
1
1

1
1

1
1
1
1

Caledonia Pa

12.10
13.57
13.77
12.44
12.38
10.89
11.91
13.39

23.35

12.34
14.32
13.31
14.10
14.16
14.28
12 . 63
11.89
12.20
15.67
11.64
10.22
9.78
12.04
12.90
15.02
15.02

17.34
12.49
10.24
12.04
12.50
12.93
14.88
11.90
11.91
14.11
13.30
12.25

12.45
12.42

21.80
22.41
22.58
22.17
22.05
20.98
21.99
20.61

27.48

22.19
22.52
19.90
22.24
22.93
22.82
22.05
21.18
21.02
23 . 53
21.87
21.29
20.69
22.09
22.27
23.41
22.41

25.01
21.46
20.92
21.92
22.18
22.64
22.31
22.00
21.99
22.25
20.00
21.20

22.18
22.19

46.12
51.69
52.61
47.39
46.59
41.49
45.37
51.02

88.94

50.94
54.56
50.71
53 . 73
53.88
54.39
48.11
45.31
46.49
59.68
44 . 35
38 . 92
37.89
45.88
49.16
57.20
49.03

66.45
47.60
39.02
45.87
47.95
49.28
56.68
45 . 32
45.37
53 . 72
50.70
46 . 50

47.38
47.35

83.07
85.38
86.01
84.48
84.02
79.94
83.79
78.54

104.68

86.37
85.80
75.82
84.73
87.33
86.95
84.02
80.70
80.09
89.64
83.32
81.12
78.85
84.18
84.86
89.20
85.37

95.59
81.75
79.72
83.50
84.18
86.25
85.00
83.84
83.79
84.74
75.83
80.10

84.49
84.52

40.83
46.07
46.25
40.63
41.05
38.43
38.49
55.95

78.80

39.93

49.97
59.80
50 . 37
46.48
47.87
42.33
43.34
46.22
52.07
37.61
32.43
34.41
38.67
42.76
47.68
41.82

53 . 73
45.31
34.84
39.76
41.40
40.79
50.39
38 . 45
38.49
50.40
59.90
42.22

42.68
40.60

59.17
53.93
53.75
59.37
58.95
61.57
61.51
44.05

25.20

60.07
50.03
40.20
49.63
53.52
52.13
57.67
56.66
53.78
47.93
62.39
67.57
65.59
61.33
57.24
52.32
58.18
100.00
46.67
54.69
65.16
60.24
58.60
59.21
49.61
61.55
61.51
49.60
40.10
57.78

57.32
59.40

60
84
126
73
98
85
85
68

373

77
164
109
91
151
131
122
98
131
94
80
36
63
58
92
136
97
100
322
87
96
126
115
120
172
85
90
103
110
113

118
119

Caledonia, Pa
Walston Pa . . .

Richland, Pa
Bennin°rton Pa

Gallitzin, Pa
Lilly Pa

Indian Creek, Pa

Coosa Ala .

Blocton, Ala
Pineville Ky

Pineville, Ky

Powelton W. Va . .

Montana, W. Va

Monongah, W. Va
Big Stone Gap Va

Big Stone Gap, Va
Pocahontas, Va
Salville, Va
Lonaconing, Md

Hondo, Mex

Alamo, Mex. . .
Cardiff, Wales. . . .

Syracuse, N. Y

Morris Run, Pa

Anthracite, Pa.

Glassport Pa

Indian Territory
Graceton, Indiana Co., Pa
Jameson Coal & Coke Co
Pinnickmnick, W Va

Coal City, Ala
Cumberland, Tenn
Marvtown, W Va

Alleghany coke
Kentucky coke . . .

Kentucky coke
West Virginia coke
Kanawha & Hocking Vallevl
Coal & Coke Co / •
Great Kanawha Colliery Co

NOTE.— Chemical analyses by T. T. Morrell, Prof. Andrew S. McCreath, Doctor Rothberg, Hugo C

17303— vii

: AND CHEMICAL PROPERTIES OF COKE

Chemical Analysis

Per Cent.

c§ <§

i * f , •>

Remarks

<D D

t-i

B ll

1| $

C/2

0 *rH

,^d

1.80

.42

.80

87.46

11.32

.69

.015

Average Standard

1.80

.130

.990

87.890

9.420

1.570

.0240

Beehive oven, 48 hours

1.81

Beehive oven, 72 hours

1.82

.310

2.610

85.080

12.000

2.050

.0060

Beehive oven

1.87

1.120

87.110

11.770

1.800

.0110

Beehive oven

.84

.500

1.130

80.480

16.470

1.420

.0140

Beehive oven

1.74

1.200

87.400 11.550

1.890

.0130

Beehive oven, B seam

1.89

1.200

89.250 9.550

1.460

.0160

Beehive oven, B seam

.47

1.500

89.800

8.210

.460

.0300

Beehive oven, B seam

.92

.220-

.736

86.100

11.970

1.700

f Latrobe coal, coked in Germany
\ retort oven

.88

.094

.174

85.753

11.544

2.435

.0640

Beehive

.75

.153

.810

92.760

6.940

.740

.0066

Beehive

.37

.430

1.040

91.560

6.360

.610

.0130

Beehive, Hull, Wyman, & Cairns

.77

1.140

.410

94.660

3.780

.590

.0070

Beehive, Cumberland colliery

.86

.017

2.900

91.048

7.548

.626

.0070

Beehive, 48-hour coke

.82

4.000

2.900

84.330

8.770

1.670

.0100

Beehive, 48-hour, unwashed coal

.82

.230

.800

89.770

9.800

.976

.0390

Beehive, 72-hour, washed coal

.67

.290

1.320 92.050

5.600

.740

.0090

Beehive, 48-hour coke

.61

.630

1.930 1 93.810

3.630

1.010

.0050

Beehive, 72-hour coke

.83

.345

.341

92.694

5.822

.738

.0063

Beehive

.89

.130

.376

87.930

10.270

.790

Beehive

.92

.614

1.020

84.667

12.234

1.465

.0241

Beehive

.77

.430

1 . 390

83.070

14.240

.820

.0190

Beehive, washed coal

.5 ! .89

1 . 350

83.800

14.850

1.080

.0050

Beehive, washed coal

.5 .84

.060

95.000

4.260

.685

.0180

.6 .91

.230

.920

86.040

12.810

.560

.0050

Semet-Solvay oven

.90

.360

1.290

89.360

8.990

.760

.0110

Beehive oven

.95

2.270

78.881

9.393

.676

Wyoming

.95

.120

.740

89.030

10.110

.690

.0120

Otto-Hoffman oven, Connellsville coal

9 .69

.460

1.770 ! 84.330

13.440

1.770

.0260

Choctaw Coke Co., beehive

.6 .81

1.000

1.200 87.310 9.400

1.090

.0160

McCreary Coke Co.

.0 .84

.130

1.220 ! 87.750 10.900

.990

. 0280

North Connellsville, beehive

.0 .80

.200 1.350 i 89.220

9.230

1.430

.0180

Beehive oven, Pittsburg coal

.0 i .94

.140 2.140 1 90.370

7.420

.960

.0300

Talladega Furnace Co.

.9 ! .81

.910 1.620 87.150

10.320

.970

.0140

Cumberland plateau, beehive

5 .75

.072

.798 : 94.657

3.775

.698

.0030

8 .78

2.480

.270 I 87.409

9.073

.768

.0080

Upper Freeport coal, beehive

9 .74

.860

.914 i 88.679

9.815

. 506

.0070

No. 3

.80

.142

1.033 92.744

5.630

.451

.0030

No. 4

.75

.126

.979 j 92.423

5.925

.547

.0030

No. 5

0 1.79

.003 91.690

8.410

.972

.0021

Gas coal seams

0 1.75

.250 92.480

7.270

.850

.0010

Screenings from whole coal bed — gas

n, F. S. Hyde, J. D. Pennock, O. O. Laudig, and E. H. Williams.

TREATISE ON COKE 335

proportion as it approached, in size, the worthless condition of
breeze. The destructive action of the use of small coke in the
Sydney blast furnaces is a cautionary example in this respect.

COMPARISON OF BEEHIVE AND BY-PRODUCT COKING

The following physical and chemical determinations made in
a series of experimental tests in coking Connellsville coal in the
Otto-Hoffman oven, and in testing Connellsville and Tuscarawas
coals in the Hiissner ovens in Germany, as shown in Table VII,
will exhibit the properties of the cokes made in these ovens. The
Connellsville standard beehive coke is given for comparison.

The analyses of the coals used in these coking tests are as
follows (Hugo Carlsson, chemist) :

CONNELLSVILLE, PA. TUSCARAWAS, OHIO

PER CENT. PER CENT.

Moisture, 212° F 840 2.530

Volatile combustible matter 31 . 600 44 . 1 10

Fixed carbon 59 . 860 46 . 280

Ash 7.700 7.080

Sulphur 820 3. 490

Phosphorus . 008 . 004

Theoretic coke 68 . 060 55 . 450

The analyses of the cokes made from the above coals follow :

CONNELLSVILLE, PA. TUSCARAWAS, OHIO

PER CENT. PER CENT.

Moisture, 212° F 030 . 130

Volatile combustible matter. ... . 510 2 . 750

Fixed carbon 86.380 84.210

Ash 13.080 12.910

Sulphur .630 3.710

Phosphorus 015 .015

The product of marketable coke from the Connellsville coal is
given at 70.10 per cent.; the coke from the Tuscarawas coal
is stated at 61.47 per cent. The percentage of breeze and ashes is
not given separately, but these have no value in blast-furnace
work.

As the Connellsville coal, in retort ovens, affords 70.10 per cent,
of useful coke, it will require 1.426 tons of coal to make 1 ton of
coke. The theoretic product of coke from this coal, 68.06 per
cent., would require 1.469 tons of coal to make 1 ton of coke,
showing a gain from deposited carbon in coking of 2.9 per cent.

The Tuscarawas coal gives 55.45 per cent, of theoretic coke,
requiring 1.80 tons of coal to make 1 ton of coke. As the oven
yield is 61.47 per cent., the deposited carbon is 9.79 per cent.,
exhibiting this large accretion of carbon from the tar of this rich
bituminous coal. It will be readily seen that, in the process of
coking the Connellsville coal in the Hiissner oven, 45 per cent, of

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|§||||||§^

c "o c

C,D C

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336

TREATISE ON COKE 337

the sulphur has been volatilized. In coking the Tuscarawas coal,
46 per cent, of the sulphur has been eliminated. The Tuscarawas
coke is too high in sulphur for use in the manufacture of pig iron.
The largest volume of the sulphur in the Tuscarawas coal is found
as bisulphide of iron, FeS2. In the process of coking, one equiva-
lent of sulphur is volatilized, leaving the monosulphide, FeS, in
the coke. Disintegrating and washing this quality of Ohio coals
would reduce the sulphur.

In furnace operations, about 4 per cent, of the sulphur goes
over to the pig iron. As the Connellsville coke contains .63 per
cent, of sulphur, it would contribute to the pig iron .0252 per cent,
of this element, which would be slightly increased from the sulphur
in the ore and flux, but these are usually small. The sulphur
limit in the best Bessemer pig is .04 to .05 per cent.

In examining the physical structure of these cokes, the effects
of the Hiissner oven in exerting a certain pressure to the charge
in coking are quite evident in both these cokes.

There are three sections of different densities in the structure
of these cokes, as shown in Fig. 1. Beginning on the sides of the

(a) Connellsville (b) Tuscarawas

FIG. 1. COKE FROM HUSSNER OVEN

oven, section a contains 1 to 2 inches of the most dense portion.
Section 6, 6 to 6J inches long, contains fairly well developed
cellular structure. Section c, next to the middle division of the
coal in coking, is greatly inflated in its cells, extending about
3 inches from its central end.

In making the determinations • shown in Table VII, Connells-
ville coke made in beehive ovens was tested by three samples each
of 48- and 72-hour coke. The table, therefore, affords a general
average of the physical properties of this standard coke.

In the Connellsville and Tuscarawas cokes, made in Germany,
in the Hiissner retort oven, four samples of each quality of coke
were used. The table gives these determinations in full, with the
general averages of each kind for comparison.

The tests of the coke from Mr. Frick's Connellsville coal, made
in Germany, in the Otto-Hoffman oven, consisted of two average
samples from the top and bottom of the oven.

The determinations of the physical properties of the Hussner-
Connellsville coke show considerable variation in density, the

338

TREATISE ON COKE

general averages exhibiting an increased density of structure
from the beehive-Connellsville of 7.7 per cent. The coke is lumpy.
It shatters easily into finger pieces, on planes nearly at right
angles to the side walls of the oven. It does not inherit the sil-
very coating that gives the beehive-Connellsville coke such a desir-
able appearance.

The Hiissner-Connellsville coke is somewhat harder-bodied
than the beehive-Connellsville coke. It is probable that the
increased hardness of body of the former will compensate for the
carbon glaze of the latter. Both hardness of body and carbon
coating protect coke in its passage down a blast furnace from the
dissolving agency of hot carbon dioxide.

The Hiissner-Tuscarawas coke is lumpy and dark-colored,
shattering quite easily under slight shocks into slender pieces, on
similar planes as the Hiissner-Connellsville coke.

The Otto-HofTman-Connellsville coke is the hardest-bodied fuel,
exhibiting good work in the oven. But its largely increased
density reduces its value as a vigorous blast-furnace fuel. It is,
on a general average, 45 per cent, denser than the standard bee-
hive-Connellsville coke, and 40.4 per cent, denser than the Hussner-
Connellsville product. It approximates in its most dense sections
to anthracite. It may be submitted, however, that the samples
furnished by Dr. F. Schniewind were very select as to complete-
ness in coking and density of structure.

It has been determined, by actual furnace work, that, for the
attainment of the maximum efficiency of coke fuel in metallurgical
operations, two prime elements are absolutely necessary: hardness
of body and fully developed cell structure.

The following table will show the work of fuels, accurately
determined, for calorific energy and economy in American blast
furnaces :

TABLE VIII

S c

CJ fl(

Size of

^ s

Kind of Fuel

Furnace

& w

Location

7)5

Year

Remarks

Feet

"5 8

See

rtt-t

Charcoal

12 by 60

3,379

Wisconsin. . . .

1,815

1891

Bav Furnace

Anthracite
Anthracite and coke .
Coke

17 by 65
15i by 55i
22 by 90

2,698
2,565
12,000

New Jersey. . .
Pennsylvania
Pennsylvania

55
58
59

2,244
2,200
1,800

1890
1885
1892

Secaucus Furnace

Edgar Thompson
Connellsville coke

From the foregoing results in blast-furnace practice, it will
appear that in the physical condition of the fuels two conditions

TREATISE ON COKE

339

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TREATISE ON COKE

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342 TREATISE ON COKE

have been established, with their relative consumption of fuel and
pig iron produced. The first is the work of the Connellsville
standard coke in the Edgar Thompson blast furnaces, where the
smelting of 1 ton of Bessemer pig iron has been accomplished with
1,800 pounds of coke. In the other, 2,200 pounds of anthracite
was- required to perform similar work.

The monthly outputs of the coke and anthracite fuels indicate
their relative calorific energies. As this great difference in fuel
energy has not its source in their chemical composition, it follows
that it must be found in their physical structure.

In this structure there are two terms of relative density: in
the anthracite 100 per cent, and in the standard Connellsville
coke 44 per cent. It is self-evident that any increase in the density
of the coke toward that of anthracite is just so much of an approach
to this slow-acting fuel, and hence its value in furnace work is
depreciated in direct proportion ; perhaps more so in the coke than
in the anthracite, as the latter decrepitates in the presence of
furnace heat and thus presents enlarged surfaces to the combining
gases in combustion, while the coke does not break up under heat,
and is therefore directly less energetic.

It was evidently for such reasons that Sir I. Lowthian Bell, in
comparing the work performed in his blast furnaces by coke made
from Bears Creek coal in beehive and Simon-Carves retort coke
ovens, remarks as follows:

"(1) Mixtures from collieries usually supplying Clarence works
and made in beehive ovens, 100 per cent. ; (2) Bears Creek coke
made in beehive ovens, 101.11 per cent.; (3) Bears Creek coke
made in Simon-Carves retort ovens, 111.11 per cent.

"In comparing the two kinds of Bears Creek coke, 1 and 2, if
No. 2 is taken as a 100 per cent., then No. 3 will stand as 109.89
per cent., exhibiting an inferiority of nearly 10 per cent, in effi-
ciency in smelting 1 ton of No. 3 iron. The average consumption
of the three fuels was 2,520 pounds, 2,548 pounds, and 2,800 pounds,
respectively. "

Comparative Yield of Coke in Different Ovens. — On the

other side, with careful work in coking, the percentages of
large coke made in beehive Hiissner, and Otto-Hoffman ovens
are as follows:

PER CENT.

Beehive oven 65

Htissner oven 70-72

Otto-Hoffman 70-72

The yield in the retort ovens is, therefore, nearly 9.02 per cent,
above the yield afforded by the beehive oven. This increased
yield in the retort-oven coke will compensate in part for its increased
density, requiring increased quantity to perform equal work with
the beehive product. In the investigation of the comparative

TREATISE ON COKE

343

merits of these two coke fuels, the vital inquiry is, Will 65 units
of beehive coke perform as much work in the blast furnace as
72 units of the denser retort fuel?

It may be noted here that the increased product of coke from
the retort ovens over that of the beehive is more apparent than
real, as has been determined in blast-furnace and cupola practice.
The Buffalo blast-furnace tests, with Semet-Solvay and Connells-
ville-beehive cokes, illustrated this in a very interesting manner.
Both cokes were made from Connellsville coal. Their chemical
composition was as follows:

Moisture
Per Cent.

Volatile
Matter
Per Cent.

Fixed
Carbon
Per Cent.

Ash
Per Cent.

Sulphur
Per Cent.

Semet-Solvay .

1 25

1 61

86 66

10 48

Beehive

1 17

89 02

9 62

The general average of the coke to smelt 1 pound of Bessemer
metal was: Semet-Solvay, 1.028 pounds; Connellsville-beehive,
.956 pounds; showing 7 per cent, of excess in retort-oven coke.
The beehive coke inherited 11.06 per cent, of cells more than the
retort product. In a further test of Connellsville coal in Otto-
Hoffman retort coke ovens, at the Glassport plant, the yield of
coke was 71 per cent.

The composition of the Otto-Hoffman and Frick cokes is as
follows :

Moisture
Per Cent.

Volatile
Matter
Per Cent.

Fixed
Carbon
Per Cent.

Ash
Per Cent.

Sulphur
-Per Cent.

Phos-
phorus
Per Cent.

Otto-Hoffman

.12

.74

88.97

10.10

.70

.012

Frick-beehive ....

.52

.098

89.55

8.95

.84

.022

Melting Power. — The following is a comparison of results
obtained from these tests at the steel works of the Lorain Steel
Company, September, 1898:

With the use of by-product coke, 9.71 pounds of iron was
melted per pound of coke; with the Frick coke, 10.64 pounds. This
shows 8.83 per cent, more iron melted with the Frick beehive
coke than the Otto-Hoffman product. The speed in melting was
decidedly on the side of the former coke, but it must be submitted
that there are economies in the retort-coke-oven work. Taking
the relative percentages of useful coke produced by these two
systems at 71 per cent, and 65 per cent., respectively, it is evident
that the retort coke will only require 1.41 tons of coal to make

344 TREATISE ON COKE

1 ton of coke, and the beehive 1.54 tons, showing 8.45 per cent,
of economy in the coal used in the retort oven. This nearly
balances the loss in the retort coke in the blast furnace. Some
economy in the labor of making the retort coke, as well .as in
the saving of the by-products of gas, tar, and ammoniacal liquor,
less the increased cost of the retort oven over the beehive, will
reduce the net margin of saving to about 30 cents per ton of coke
produced.

It has been found quite difficult to procure an accurate state-
ment of the work and cost of making coke in the retort coke ovens,
especially the cost of repairs. The tabulated statements, Tables
IX, X, XI, XII, and XIII, will throw some light on these matters:

TABLE XI

COST AND PRODUCTION OF OTTO-HOFFMAN COKE OVENS AT JOHNS-
TOWN, PENNSYLVANIA, FISCAL YEAR 1898-1899

COST
AMOUNT TOTALS PER TON

Superintendents, assistants, clerks,

chemist, pumping station $ 6,914.40

Labor on coal 7,826 . 78

Labor, washing and mixing coal, and

team service 2,808. 91

Labor at ovens 39,845. 14 $57,395. 23 $ . 425

Repairs to ovens 3,464. 55

Repairs to tracks, pumping station,

and general repairs 2,100.67

Coal-mixing machinery 4,550 . 70 10, 1 1 5 . 92 . 075

Oil, waste, packing, tools, etc 2,998.84

Transportation 6,005. 25

Loam and clay 343 . 80

Office expenses and incidentals 4,653.72

Coal for steam and heating ovens 7,425.04 21,426.65 . 158

General expenses 2,319.91 .017

Taxes 1,222.00 .009

Cost of coking 92,481 . 71 . 684

213,761.64 net tons coal at .89. . 190,372.68 1.409

Gross cost of coke 282,854. 39 2.094

Credit for by-products 23.371 . 85 . 173

Net cost 135,083.40 net tons coke 259,482. 54 1 . 921

Firing new ovens 4,955. 14 .039

Mud-dam... 371.92

29,089 ovens $264,809. 60 $1 . 960

TREATISE ON COKE 345

BY-PRODUCTS

CREDIT AMOUNT TOTALS
56,100,000 cubic feet of gas at 5 cents per thou-
sand $ 2,805.00

3,433.90 net tons of tar at $5.06 17,366.83

263.37 net tons sulphate of ammonia at $50.47 . 13,291.65

275.37 net tons concentrated liquor at $22.87 .. 6,297.89 $39,761.37

DEBIT

Labor at by-product plant 10,958. 92

Repairs at by-product plant 1,518.49

Lime and sulphuric acid 3,547.97

General expenses 364 . 14 16,38-9 . 52

Net credit for by-products ; . . . $23,371 .85

PRACTICE . PER CENT.

213,761.64 tons coal used for coke

135,083.40 tons scale weight coke produced 63. 19

3,433.90 tons tar produced , 1.61

263.37 tons sulphate produced .12

275.37 tons concentrated ammonia liquor produced .13

CUBIC FEET
Gas 262

TABLE XII

COST AND PRODUCTION OF OTTO-HOFFMAN COKE WORKS, FISCAL

YEAR 1895-1896

COST

AMOUNT TOTALS PER TON

Superintendents, assistants, clerks,

chemists, pumping station $ 6,489. 14

Labor on coal 3,302 . 09

Labor at ovens 24,612.96 $34,404.19 $ .653

Repairs to ovens 14,298.20

Repairs to tracks, pumping station,

and general repairs 2,370.04 16,668.24 .317

Oil, waste, packing, tools, etc 3,326 . 78

Transportation. 2,722. 75

Loam and clay 311 . 17

Office expenses and incidentals 1,311 .77

Coal for steam and heating ovens. .... 7,843.60 15,516.07 .295

General expenses 1,937. 37

Taxes 80.00 2,017.37 .038

Cost of coking 68,605 .87 1 . 303

66,965.62 net tons coal at $. 98 65,681. 63 1 . 274

Gross cost of coke 134,287 . 50 2 550

Credit for by-products 5,281 . 64 . 100

Net cost 52,666.43 net tons coke.. . $129,005.86 $2.450

346 TREATISE ON COKE

BY-PRODUCTS
CREDIT AMOUNT TOTALS

Cubic feet gas at

1,635.75 net tons tar, at $5.95 $ 9,713.71

302.62 net tons sulphate of ammonia, at $39.99 12,100.69 $21,814.40

DEBIT

Labor at by-product plant. . . 11,387. 26

Repairs at by-product plant 902 . 20

Lime and sulphuric acid 4,243 30 16,532 . 76

Net credits for by-products $5,281 . 64

PRACTICE PER CENT.

66,965.62 tons coal used for coke

52,666.43 tons scale weight coke produced.

52,666.43 tons coke credited 78. 65

1,636.75 tons tar produced , 78. 65

302.62 tons sulphate produced 2. 44

CUBIC FEET
Gas. 45

TABLE XIII

COST OF MAKING COKE IN BEEHIVE OVENS

CENTS

Drawing coke 1800

Leveling 0200

Yard boss, $75 per month 0050

1 locomotive engineer, $12.25 \ nnon

1 charger, $1.68 per day / ' '

1 track cleaner, 1 car trimmer, $1.35 per day 0040

1 car shifter, $1.75 per day 0030

1 track man, $1 .50 per day 0020

3 cart horses 0040

Water 0100

Half superintendent's salary, $175 per month 0050

Repairs 0300

Interest on investments .0030

Taxes, insurance, etc . 0250

Coke working extra . 0250

3520

1 .5 tons of coal at 89 cents per ton $1 . 3350

Repairs per ton of coke 0135

Total $1 . 7005

Johnstown, Pa., April 1, 1899.

Table IX exhibits the time required to make 1 ton of coke in
Otto-Hoffman coke ovens at Glassport and Johnstown, Pennsyl-
vania, with the time used at Holland. No. 3, Germany.

Table X affords in full details the several departments of labor
in making coke and saving by-products, with the aggregate cost of
each department, as the relative cost per ton for labor, in Glassport
and Johnstown.

TREATISE ON COKE 347

Table XI affords the cost of the several elements of labor
and materials required in making 1 ton of coke and saving by-
products. It also affords the ultimate aggregate cost of coke,
charging the cost of coal at 89 cents per net ton, and crediting
the manufacture of the coke with the value of the saved by-products,
making the net cost of 1 ton of coke $1.92, including ordinary
repairs of ovens, but excluding extraordinary expenses.

Table XII gives cost and production of Otto-Hoffman coke
ovens at Johnstown during the fiscal year, 1895-1896. Evidently
these costs include new construction, and the large cost per net
ton of coke has not been used in calculations. The moderate cost
of $1.92 has been taken for comparison. The cost of maintenance
of these Otto-Hoffman coke ovens is only incidentally afforded in
the foregoing tabulated statements. These do not cover a suffi-
cient length of time to give reliable data in this important element
of cost. Taking what is given in these statements of the minimum
average cost of repairs per net ton of coke produced, with the
saving of the by-products and avoiding unusual expenses, it is
8 cents. This is included in the net cost of $1.92 per ton of coke
made. This plant of coke ovens is comparatively new; as it ages,
the cost of repairs will increase largely.

In this connection it may be interesting to compare the cost
of making coke in the Connellsville-beehive coke oven, as shown
in Table XIII. It is estimated that the life of a beehive coke
oven is 16 years. To maintain it during this time will cost: for
bottoms, $34.50; tunnel heads, $32; and fronts, $76; making
in all $142.50; say, $1.50 per oven during the 16 years. Taking
the average annual product of an oven at 700 tons, the cost of
repairs will be $.0133 per ton of coke. Adding this to the cost of
making coke, will give the total net cost of producing coke in a
beehive coke oven at $1.7005 per net ton, showing an economy
on the side of the beehive of $.2195, as compared with the work
of the retort ovens at Johnstown.

It is not assumed that the cost of production of coke at the
Johnstown retort coke ovens is a minimum quantity, but it indi-
cates that the claims of large profits in this type of coke oven over
the ancient beehive oven are not assured in the foregoing instances.
When the great difference in the cost of these ovens is considered,
with the relative interest on investment in plants, the economies
will still be increased on the side of the round oven. But it must
be considered that there is an additional credit due the retort oven.
Taking the relative product of coke from Connellsville coal at 65
per cent, for the beehive and 72 per cent, for the Otto-Hoffman,
respectively, it is evident that the former will require 1.538 tons
of coal to make 1 ton of coke, and the latter 1.39 tons to 1 ton of
coke, exhibiting an economy in the use of coal in the retort oven
of 296 pounds. This, at 89 cents per ton, gives $.132 of credit to
the retort oven. The relative costs of producing coke, per net

348 TREATISE ON COKE

ton, in the two cases under consideration are as follows: beehive,
$1.7005; Otto-Hoffman, $1.788, thus showing substantially equal
cost in the production of coke by these types of coke ovens.

If a further investigation of the interest in investment on the
plants of ovens and by-product saving is considered, with the
additional fact that 72 per cent, of retort coke is only equal to
65 per cent, of beehive coke in blast-furnace operations, the value
of the retort coke ovens, considered in this comparison, dissipates
much of the claims for economy. But their essential usefulness
must be recognized in their capacity to produce coke from the
dry coals that could not be made into good coke in the beehive
ovens. This element of their usefulness will increase as the
coal suitable for the open-oven manufacture becomes partially
exhausted.

EFFECTS OF THE SEVERAL TYPES OF COKE OVENS ON THE PHYSICAL
PROPERTIES OF THEIR COKE PRODUCTS

With the manufacturers of coke for metallurgical uses, the
fact is well established that coke ovens dominate, in a large degree,
the physical properties of their products. It is, therefore, now
proposed to consider the relative effects of the typical coke ovens
on the physical -condition of the coke produced in each kind. It
is well known that in the great variety of coke ovens there are
only three root types: the beehive, or round, oven; the Knab, or
retort, oven; and the Appolt, or upright, oven.

In the beehive and other horizontal types of coke ovens, it will
be readily understood that the governing element in their opera-
tions is similar; a broad charge of coal, 24 to 26 inches deep, afford-
ing the greatest liberty to the charge of coal in fusing to develop
the fullest cellular structure and to glaze the upper portion of the
coke with deposited carbon, giving it a sheen that, in addition to
its appearance, contributes to its resistance to the dissolving
agency of hot carbon-dioxide gas in blast-furnace and cupola
operations.

The moderate heat of these ovens, in the initial operations of
coking, prevents a too inflated or frothy physical structure in the
coke. The physical properties of the coke from this type of coke
oven are most excellent. With the use of the best qualities of
coking coals in the manufacture of coke, the product is always
the best possible for blast-furnace use.

This family of coke ovens yields 63 to 66 per cent, of marketable
coke with 2 to 3 per cent, of small coke and ash. The percentage
of coke obtained depends on the skill and economies applied in
the coking operations, as well as in the quality of the coal used.

The Knab coke oven, with its numerous offspring of these
narrow vertical ovens, has chambers 18 to 24 inches in width
and 25 to 35 feet in length. The Simon-Carves, Semet-Solvay,

TREATISE ON COKE 349

Hiissner, Seibel, and Otto-Hoffman are examples of this type of
oven. With narrow chambers and charges of coal 5 to 6 feet
deep, a certain amount of pressure is exerted in the process of
coking, producing coke of increased density of structure as com-
pared with the product of the round or the horizontal ovens.
This density of coke is readily seen near the side walls of the coking
chamber, and especially at the bottom section of the oven. As
the coking begins at the sides and bottom of the oven, a minimum
quantity of carbon is deposited from the gases evolved in coking.
From the great heat maintained in these ovens by the combustion
of gases in the bottom and side flues, the operation of coking
begins quickly and is usually accomplished in a thorough manner,
avoiding much of the black ends that occasionally appear on coke
from the horizontal ovens.

The vertical posture of the chamber of the Appolt oven confers
on its coke the densest physical structure. It is probable that
this oven could be used in the manufacture of coke from coals
very rich in fusing matter, as it would tend to repress a too inflated
structure in the coke. These retort coke ovens produce from
70 to 73 per cent, of marketable coke.

Table XIV will show the relative influence of these coke ovens
on the physical properties of their coke.

In this table, reference letter (a) gives the average phys-
ical properties of the standard Connellsville coke made in the
beehive coke oven. This general average embraces samplings
taken in the coke from the top, middle, and bottom of the charge.
It is therefore a fair average of the best quality of this coke. (6)
gives the results of a coking test made in a Hiissner retort coke
oven in Germany, from a shipment of Connellsville coal, during
the early movement to introduce these narrow coke ovens into
the United States of America. Samplings of this coke were
secured from the side, middle, and bottom of the coke made in
this oven; the average result is given in the table, (c) exhibits
the physical properties of coke made in the experimental coking
plant of the Semet-Solvay Company at the Solvay Chemical Works,
Syracuse, New York. It was made from a shipment of coal from
the Connellsville field in 1895. This average determination of
the physical properties cff this coke embraces samplings from top,
middle, and bottom of the charges, (d) exhibifs the work of the
Otto-Hoffman retort coke oven, from a shipment of Connellsville
coal sent to Germany for the purpose of a general test. The
average of two samplings from top and bottom is given in the
table, (e] gives the physical properties of coke made from Morris
Run coal, Tioga County, Pennsylvania, in a beehive coke oven.
(/) exhibits the physical properties of coke made in a Semet-
Solvay coke oven from the Morris Run coal. The design was to
determine the influence exerted by this type of retort coke oven
in repressing cellular structure in the coke, as compared with the

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350

TREATISE ON COKE 351

product of the beehive coke oven, with its horizontal posture and
freedom of action in coking, (g) , (h) , (i) , (k) , and (/) afford exam-
ples of the physical properties of cokes made from different qualities
of coals in beehive coke ovens, (m) gives the anthracite or natural
coke. It has no cell structure and is the most dense fuel used in
blast-furnace operations. It will be interesting to compare the
relative percentage, by volume, of coke to cells in the foregoing
tests, as shown in Table XV.

TABLE XV

COKE CELLS

PER CENT. PER CENT.

(a) Connellsville beehive standard coke 43. 93 56.07

(6) Hiissner, Connellsville coal 48 . 24 51 . 76

(d) Otto-Hoffman, Connellsville coal, German test 69.17 30.83

(e) Morris Run coal, beehive oven 41 .82 58. 18

(/) Semet-Solvay, Morris Run coal 47.68 52.32

(g), W, (*)» (&). and (/) beehive, various coals,

general average 44 . 78 55 . 22

(m) Anthracite, general average 100.00

TABLE XVI

PER CENT.

Anthracite 100 . 00

Connellsville standard beehive coke 43 . 93

Hiissner, Connellsville coal, Germany 48. 24

Otto-Hoffman, Connellsville coal, Germany 69. 17

Otto-Hoffman, Connellsville coal, Glassport, Pennsyl-
vania 53 . 73

Semet-Solvay, Connellsville coal, Syracuse, New York. 50. 12

Morris Run coke, beehive oven 41 . 82

Morris Run coke, Semet-Solvay ovens 47 . 68

Average of all retort-oven coke, Connellsville coal .... 55.72

Average of all beehive ovens on various coals 42 . 88

The above statements will exhibit in a brief manner the effects
of the different types of coke ovens in repressing the physical
structure of the coke, as compared with anthracite at 100 per cent.
Direct comparisons can thus be made of the coke products of the
beehive and retort types of coke ovens.

Taking the volume of the body of the beehive-Connellsville
coke at 43.93 per cent., and the Hiissner coke from Connellsville
coal at 48.24 per cent., the latter retort oven has compressed its
coke 8.94 per cent. The Semet-Solvay oven, using Connellsville
coal, compresses its product 11.23 per cent. The Otto-Hoffman,
using Connellsville coal, compresses its product 24.49 per cent.
The general average of the retort coke ovens represses their product
21.03 per cent.

But we have a very interesting test of the effects of the
beehive and Semet-Solvay ovens, using Morris Run coal, on
their coke product. The beehive oven gives the coke a cellular

352 TREATISE ON COKE

structure of 58.18 per cent., while the Semet-Solvay retort oven
gives only 52.32 per cent, of cells in its coke, a difference of 11.02
per cent, in favor of the beehive structure; or, in other words,
the retort oven densities its coke 11.02 per cent, over that of
the round or beehive oven.

It follows, therefore, that, as the calorific energy of any fuel is
in proportion to the extent of its surface exposed to the oxidation
agencies in a blast furnace, then the greater this surface, within
certain limits, the more energetic the combustion As anthracite,
or natural coke, is the most dense of fuels and the least energetic
in its combustion, it follows that, in the preparation of artificial
fuel in coke ovens, every approach in the density of the coke to
that of anthracite reduces its calorific energy and therefore its
value for blast-furnace operations.

Of course in this conclusion, the economy of the work in pro-
ducing coke in the retort ovens, with the additional revenue
derived from the by-products, must be considered as an offset of
credit against the density of the coke. But if the prime effort is
to produce the most energetic fuel for blast-furnace work, then
the repression of the cells and the densification of the coke in the
narrow ovens cannot be defended.

CHAPTER VIII

THE LABORATORY METHODS OF DETERMINING THE RELA-
TIVE CALORIFIC VALUES OF METALLURGICAL FUELS

There can be little difference of opinion in deciding that the
test in blast-furnace use of the three principal fuels is the most
reliable method of determining their relative calorific values, pro-
vided the conditions of the work are equalized justly.

This assumes that such tests shall have been made in blast
furnaces whose dimensions have been proportioned to assure the
best possible results in the fuel used'; not only this, but that the
pressure and heat of blast have been in harmony with the require-
ments of the fuels, in order to accomplish their complete combus-
tion and economical application.

It is further assumed that in these practical determinations
of the calorific values of these fuels in blast-furnace work, three
chief considerations shall have been accurately noted: (1) The
weight of fuel to smelt 1 ton of pig iron; (2) the time required in
smelting; and (3) the purity of the fuel. The first shows the
economy in fuel; the second, economy in the cost of superintend-
ence; and the third, exemptness from dangerous impurities in the
pig metal produced.

The table on page 354 exhibits, approximately, the work of
the three chief fuels in blast-furnace operations.

Equating the results shown in the table to approximately equal
practical conditions, the relative calorific efficiency of these three
fuels will stand as follows: Coke, 100 per cent.; charcoal, 90 per
cent.; anthracite, 78 per cent.

It is submitted that the statements in the table of blast-
furnace work are practical general averages. They are greatly
exceeded by recent work, as will be seen in the following
statement :

"Furnace No. 1 of the Carnegie Steel Company, at Duquesne,
Pennsylvania, has just made a record for long blast on one lining
and for output that will probably stand for some time. This fur-
nace was blown in on June 8, 1896, and was in continuous blast
until October 21, 1903, a period of 7 years, 4 months, and 13 days.
During its blast, the furnace turned out 1,287,400 gross tons of
Bessemer pig iron. The best day's record was on October 26,

353

354

TREATISE ON COKE

1898, when the furnace made 748 tons and 350 pounds. The best
week's work was for the week ending October 29, 1898, when the
furnace made 4,990 tons and 209 pounds. The best month's
work was October, 1898, when the product was 18,672 gross tons
of Bessemer iron. The average coke consumption per ton of pig
iron was 2,020 pounds. This furnace is 100 feet by 22 feet in
size. It will be repaired and relined."

COMPARATIVE WORK OF FUELS IN BLAST FURNACES

& '

c
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Kind of Fuel

Furnace

aj %

Location

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General Remarks

O O

£<£|

I~2Z

PL,

Charcoal

10' 5" X 45'

1,488

Michigan

59.00

1,844

f Spring Lake Furnace,
( Lake ore

Charcoal
Charcoal

10' X 48'
12' X 60'

2,615
3,379

Michigan
Wisconsin

60.00
55.00

2,060
1,815

Bay Furnace, Lake ore
f Hincle Furnace, Ash-
S i -i

( land

Averages

2,494

58.00

1,907

Anthracite

17'X65'

2,698

New Jersey

55.00

2,244

f Secaucus, Hudson
( Company

(No. 9 Furnace, 75

Anthracite

16' 6" X 65'

2,376

New Jersey

55.21

2,347

< per cent, coal, 25 per

( cent coke

Averages
Coke

22'X90'

2,537
10,536

New Jersey
Pennsylvania

55.10
59.00

2,295
1,737

f Edgar Thompson,
( Connellsville coke

Coke

22' X 90'

12,000

Pennsylvania

59.00

1,800

f Edgar Thompson,

( Connellsville coke

Coke

22' X 100'

17,700

Pennsylvania

59.00

1,850

f Duquesne Furnace,
\ Carnegie Steel Co.

Averages

13,412

Pennsylvania

59.00

1,796

It is further submitted that the above practical results, in
actual furnace work, afford sure standards for laboratory deter-
minations of the value of fuels for metallurgical purposes. It has
been shown that the two chief essential physical requirements in
fuel for blast-furnace use are hardness of body and well-developed
cell structure.

The first essential physical requirement of hardness of body is
important in protecting the fuel in its downward passage in a
blast furnace from loss in dissolution by carbon dioxide. Sir
I. Lowthian Bell long ago pointed out, first, "that the carbon, as it
exists in different qualities of coke, is not influenced in the same
degree by this solvent power of CO2\ second, that the soft descrip-
tion, known as black ends, is more easily attacked than the hard,
silvery -looking kind."

In two tests, with hard- and soft-bodied coke, Mr. Bell proves
that the hard coke, pulverized to the size of mustard seed, exposed
at a temperature of melting zinc for f of an hour to a current
of CO2 gave a mere trace of CO. The soft coke, similarly treated,
in \\ hours gave 92 cubic centimeters of CO. This indicates the

TREATISE ON COKE 355

loss that the soft variety of coke suffers by dissolution in the
blast furnace is nearly 8 per cent.

In the second requirement, the valuable results from full
development of cells in coke are readily understood, as these cell
spaces afford free entry to the ascending hot gases, which thus
permeate the coke thoroughly and impart to it a high temperature,
which aids materially in its rapid combustion. In addition to
this, the large area of the cell spaces affords ample surface for the
hot oxygen of the blast to act on, securing rapid combustion with
high temperature and calorific energy, resulting in the rapid work-
ing of the furnace.

Now anthracite is not lacking in hardness of body; in this
physical property it is equal to the average cokes. We have seen,
however, that it requires 2,347 pounds of anthracite to do the
work of 1,796 pounds of coke in a blast furnace. It is evident,
therefore, that the property of hardness of body alone will not
afford the best results in smelting pig iron. The great density in
this fuel confers on it the slowest combustion in a blast furnace.
Only for the decrepitation, which takes place near the tuyeres,
its rate of combustion would be further retarded.

On the other hand, coke possesses an average hardness equal
to the anthracite; but any slight difference of hardness of body
cannot be urged to account, in any important degree, for the
great difference in the calorific energy of coke over anthracite in
blast-furnace operations.

As the difference in the calorific efficiency of these fuels has
not its exclusive genesis in the physical property of hardness of
body alone, it is evident that it must be looked for elsewhere.
This has been discovered to be in the cellular structure of the
coke, other conditions being equal.

In the best varieties of coke the aggregate volume of the cell
spaces to the body of the coke is as 44 to 56 nearly. In some
cokes, this cell structure is too inflated, conferring on it brittleness
in furnace work, with lack of energy at the tuyeres.

From these conditions, in the anthracite and coke fuels, it is
evident that in the best varieties of each we have, from actual
work in the furnace, two different results: in the anthracite, a
dense, languid fuel, and in the coke a cellular, vigorous fuel. The
ratio of the former to the latter in calorific energy or speed is as
about 1 to 3, assuming that they have about the same or equiva-
lent chemical composition.

LABORATORY TESTS

From these tests of the physical properties of these two impor-
tant metallurgical fuels, the following methods of determining the
values of all qualities- of coke for blast furnace or for similar uses
have been established :

356 TREATISE ON COKE

Cell Structure. — An average sample of the coke is carefully and
accurately cut into inch cubes. One or more of these cubes,
depending on the accuracy required in the determinations, is
thoroughly dried, and, when cooled, carefully weighed. This gives
the weight of the body of the coke in its dry condition. The
cubes are then immersed in a vessel of distilled water and put
under the receiver of an air pump, the air pumped out of and the
water forced into the cells. The cube or cubes are again weighed;
the difference in weight, equated to the specific gravity of the coke,
gives the aggregate cell space in the cube of coke.

An easier method is suggested by the late Doctor Sterry Hunt,
in the "Report of the Geological Survey of Canada," 1863-6,
pages 281-3.

His method is to select suitable specimens of any size or shape,
usually pieces from 20 to 40 grams in weight ; these are to be dried
and weighed; then fill their cells with water and weigh in water;
the pieces are then taken out of water, the excess of water on
their surfaces carefully removed, and weighed again in air. These
operations furnish all necessary data for calculating the following
properties :

1. The apparent specific gravity, or the relationship between
the whole mass of material and an equal volume of water.

2. The true specific gravity or the specific gravity of the body
of the coke or other matter.

3. The aggregate of cell space in one hundred volumes of
material, or percentage of cells by volume.

4. The volume of cells in a given weight of material, as cubic
centimeters in 100 grams.

The loss in weight of the material saturated with water, being
equal to the volume of water displaced by the mass, enables us
to determine the specific gravity of the latter; while this loss in
weight, less the weight of the water absorbed by the mass, gives
the true volume of water displaced by its body, and hence the
means of determining its specific gravity.

The division of the amount of water absorbed by the amount
of water displaced gives the amount of volume of the cells in a
unit of the material, and the division of the weight of the water
absorbed by the weight of the dry mass gives the aggregate vol-
ume of cells in a unit of the mineral.

Let a = weight of dry material ;

b = weight of water that it can absorb ;

c= loss in weight, in water, of saturated material.

Then, c : a = 1,000 : x = apparent specific gravity, or the
specific gravity of the mass.

c — b : a = 1,000 : x = true specific gravity, or specific gravity
of the body of the mineral, water being 1,000.

c : b = 100 : x = percentage by volume of the cells in the
mineral.

TREATISE ON COKE 357

a : b = 100 : x = volume of cells in 100 parts by weight of the
mineral; say, cubic centimeters in 100 grams.

In coke determinations, Messrs. Mills and Rowan, in "Chemical
Technology," Philadelphia, 1889, submit the necessity of some
changes in the foregoing methods, as follows:

"Suitable specimens from 20 to 40 grams in weight were selected
to represent the average physical condition of the coke. They
were thoroughly brushed to remove any loosely adhering particles
that might fall off during the experiments and thus vitiate the
results, and were weighed just as received; they were dried at a
temperature of 100° centigrade for 1 hour, cooled under the desic-
cator, and weighed, the loss in weight representing the amount of
moisture found in the specimen as received.

"Great difficulty was experienced in thoroughly filling the cells
with water, on account of the small adhesion between the surface
of the coke and the water, but, after considerable experimenting,
the following general plan was adopted.

"In filling porous substances generally with water, two methods
are in use ; one to soak the specimens in water for a time and then
to place them in water under the receiver of an air pump, and
exhaust until no more air is given off; and the other to keep them
suspended in boiling water until the pores (cells) are filled with
water, as is shown by their ceasing to gain in weight on taking
them out, cooling, and weighing. In this case it was found more
expedient to use a combination of these two methods.

"In the determination of the specific gravity, there are two
sources of variation, one inherent in all specific gravity determina-
tions, and unavoidable, the other accidental and in a measure
disappearing in the averages. The first error is due to the possible
presence of water-tight pores, or cells, causing a minus error in the
determinations. The other error is due to the possible presence in
a piece of coke of a small piece of slate, causing a plus error."

Tests for Strength. — The cubes of coke used in determining
the cellular structure are dried, or others that have not been wet
are then used to determine the capacity of the coke for bearing
furnace burdens without crushing, in a machine for testing the
compressive strength of materials.

The hardness of the body of the coke is determined by the usual
methods; but when great care is required, the resistance of a cube of
coke to abrasion, under specific pressure and speed on an emery wheel
is used to ascertain this important property of hardness of body.

With the data obtained under these methods, it is demonstrated
that an accurate estimate can be made of the calorific value of the
coke for blast-furnace purposes, as the following estimate, followed
by a blast-furnace test, will show:

In October, 1891, Mr. J. H. Allen, vice-president and general
manager of the Cumberland Valley Colliery Company, Pineville,

358

TREATISE ON COKE

D CHEMICAL PROPERTIES OF COKE

Beehive oven coke.
Beehive oven coke.

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Connellsville, Standard
Pineville, Kentucky.. .

Kentucky, sent a sample of his
coke for examination and esti-
mate of its value as a metal-
lurgical fuel. The accompanying
table and report were returned
to Mr. Allen.

Dear Sir: — In compliance with
your request of September 17, I have
examined the sample of your coke
that you forwarded for this purpose.
Assuming that this sample of your
coke, submitted for chemical and
physical examination, is a fair aver-
age of its quality, I have had seven
physical tests made, giving the aver-
age of the seven in the accompany-
ing table. In this table, the Con-
nellsville coke is included for purposes
of comparison between this and other
cokes. On general principles, coke
for metallurgical uses should possess
hardness of body with well-developed
cell structure so as to insure exemp-
tion from combustion in the upper
regions of a blast furnace, and to
afford the utmost calorific energy in
the lower region of the furnace.
Hardness of body in coke prevents
its dissolution by the furnace gases,
in a section of the furnace where it
is not only a waste of fuel, but
where it disturbs the orderly working
of the furnace. The large cell devel-
opment in coke assures its calorific
energy in combustion.

The coke you have submitted
from your Pineville works shows
that it has been carefully and intel-
ligently treated in the coke ovens.
There are no indications to show
where an improvement could be
suggested in this respect. The coke
has the usual slender columnar
structure somewhat peculiar to Ken-
tucky cokes. It will be seen in the
table that the cellular structure of
this coke is somewhat below the
standard Connellsville.

This slight physical defect is
compensated, in a great measure, for
blast-furnace use by the slender finger
structure of the coke as it comes
from the coke ovens. Its burden-
bearing qualities are equal to the
highest blast furnaces now in use or
likely to be attempted in time to
come. The hardness of this coke is
so near that of the Connellsville

TREATISE ON COKE

359

standard that it is not necessary to draw any special distinction. The
chemical analysis shows that it is a much purer fuel than that of the
Connellsville standard. The ash is remarkably low, only one-third of the
volume found in the Connellsville. As a clean fuel, it has few if any supe-
riors. It will also be noted that the exceptionally low percentage of the
element phosphorus in this coke gives it special adaptability for smelting
Bessemer pig iron. The sulphur is low, under that of the standard. It will
be found a very superior fuel for blast-furnace purposes, for smelting iron in
cupolas, and for all metallurgical purposes in which coke is used as a fuel.

JOHN FULTON, E. M.

Immediately following this report, a shipment of this coke was for-
warded to the Nashville Furnace Company for an actual test of its
value in this furnace. The following letter shows the result of this
test.

NASHVILLE, TENNESSEE, October 31, 1889.
MESSRS. J. D. ANDERSON cfc Co.

Gentlemen: — In reply to your favor of this date, we have to say that
on the 23d, 24th, and 26th inst., we made a test at our furnaces of the Cumber-
land Valley Colliery Company's Pineville coke. As the coke was new to
us, we, as a matter of prudence, charged light in the beginning, using 4,000
pounds of ore, 2,100 pounds of lime, and 2,800 pounds of coke. The furnace
being too hot on the 23d, we increased the ore to 4,800 pounds. The fur-
nace still being too hot on the 24th inst., we increased to 5,300 pounds,
being the same burden we had carried with Pocahontas coke, with as good
results. When we came to understand the nature of the Pineville coke, we
produced as much iron and a higher grade of iron than we had previously done
with other cokes. Yours, etc.,

H. W. BUTTORFF,

President and General Manager.

J. H. HANLEY,
Superintendent and Furnace Manager.

Test for Resistance to Solution by C02. — An additional test has
recently been introduced, in determining the resistance of coke to
the dissolving agency of hot carbonic-acid gas, which proves the
relative hardness of body in anthracite and coke fuels.

Average samples of each kind of fuel are powdered and thor-
oughly dried. About 800 cubic centimeters are placed in a test
tube. Hot carbonic-acid gas is passed over the powdered coke
during a fixed time. The coke is carefully weighed as it is placed
in the tube, and after it is taken out the difference in weight shows
the loss by dissolution and the relative hardness of body in resist-
ing dissolution by this test.

TABLE SHOWING RESISTANCE TO SOLUTION BY CO2

Kind of Fuel

Iff!

05 <D

nJO

Remarks

^ ^>C a>

o v

^H^ ^

Anthracite

96.0

4.0

2.5

Connellsville coke

94.5

5.5

3.7

Coked in Otto-Hoffman ovens

Connellsville coke

91.9

9.0

3.0

Coked in beehive ovens

Morris Run

88.8

11.2

2.6

Coked in Semet-Solvay ovens

Bennington

86.1

13.9

2.4

Coked in beehive ovens

360 TREATISE ON COKE

The preceding table exhibits some tests made in this way, by
the late Doctor James J. Fronheiser.

The percentages in the CO column indicate, approximately,
the probable loss in these fuels from softness of body.

The following statement shows the ultimate average compress-
ive strength of the above fuels, per cubic inch, without crushing:

POUNDS

Anthracite 3,000

Connellsville coke 2,260, coked in Otto-Hoffman ovens

Connellsville coke 1,204, coked in beehive ovens

Morris Run coke 1,360, coked in Semet-Solvay ovens

Bennington coke 848, coked in beehive ovens

From the foregoing data, it will readily appear, that labora-
tory determinations of the properties of these fuels will afford
very accurate results in estimating their several calorific values in
metallurgical operations.

It may be noted here that in selecting the several portions of
the coke for cutting into cubes for physical tests, that the outside,
inside, top, middle, and bottom pieces have been carefully selected,
so as to secure the true general average.

The Buffalo blast-furnace tests of Connellsville, beehive coke,
and Semet-Solvay coke, made from Connellsville coal, is interest-
ing as exhibiting the relative calorific energies of these fuels. The
work of 2 days was selected, during which the furnace was con-
sidered to be in equally favorable conditions for testing these fuels,
1 day to each kind.

The following results were obtained: 1895, May 14, 2,193
pounds of Connellsville coke to 1 ton Bessemer metal; 1895, May
20, 2,400 pounds of retort coke to 1 ton Bessemer metal. Exhib-
iting an increased heat value of 8.21 per cent, of the former above
that of the latter product.

Taking the cellular spaces of these fuels, at a general average
of 56 per cent, in the beehive to 50 per cent, in the retort, the
increased volume of the former over the latter is 10.7 per cent.,
exhibiting a slight increase in theoretic heat value over the blast-
furnace tests.

CHAPTER IX

THE LOCATING OF PLANTS FOR THE MANUFACTURE

OF COKE

Preliminary Considerations, — In former chapters, the methods
of preparing coal for making coke with the ovens adapted for
producing the best metallurgical fuels have been considered. It
is evident that the first important effort that should elicit the full
attention of the manufacturer of coke is to produce it of a uniform
first-class quality. This will assure his product a ready market,
and secure his men continuous work at the ovens in the usual
times of uninterrupted business. The second effort relates to a
consideration of how, in the economies of location of a coking plant,
full profit can be secured to the manufacturer.

It is assumed that wise coke makers do not enter this branch
of industry alone in the interest of science, but reasonably expect
moderate compensation for capital invested, time devoted to the
industry, and compensation for the exhausting coal.

In order to secure this second condition, as far as it can be
controlled by the location of the coking plant, it will readily appear
that this element, in affording economy in the coking operations,
requires careful consideration. Without in the least under-
valuing the good practical judgment of the coke manufacturer,
it may be submitted that it will conduce to economy to secure
the professional service of an expert engineer in the work of loca-
ting the coke-oven plant. Sometimes a few dollars are saved by
not employing a competent engineer, with the result that in the
end a great many are wasted.

In common with modern progress in the economical location of
industrial plants, the arrangements of the coking plant and its
source of coal supply should receive the benefits of recent improve-
ments in these respects. The principles that evidently should
govern the location of a coking plant consist in affording full
facilities in the performance of all the work in the manufacture
of coke with its resultant economizing in this labor. The location,
however, is governed, in part, by the topography of the locality
in which it is designed to establish the work. The general plan
will require to conform to these conditions.

It may be noted that the site for the coke ovens is generally
determined by the location of the coal mine opened for the supply

361

362

TREATISE ON COKE

of coal to the ovens. A little preliminary careful attention in the
location of the coal mine with a view of affording the best possible
ground for the ovens would conduce to economies in both.

In the location of plants of coke ovens of one or more banks,
the gradients of the larry tracks on the ovens, as well as the tracks
of the railroad sidings, should afford descending grades of at least
1 per cent., so as to secure the movements of the larries and rail-
road cars by gravity, thus avoiding mainly the use of locomotives
or horse power in these operations.

FIG. 1. ELECTRIC COKE LARRY

It may be noted here that electrical power in moving the coal-
charging larries along banks of coke ovens is rapidly superseding
horse or mule power. At this writing many of the large plants
of beehive or retort coke ovens have this power in full operation,
securing rapid movement of the larries and quick charging of the
coke ovens with coal after the coke has been drawn out, increasing
the time of coking in the oven and securing a more complete
product of coke.

Fig. 1 shows an electrically operated larry. The sheet-steel
box hopper a is about 8 feet 6 inches square and 2 feet 6 inches
deep. The bottom of the hopper tapers on all four sides as shown.
The larry shown has but one discharge chute b and is used for

TREATISE ON COKE 363

bank ovens that are charged from one side of the larry. If the
larry track is situated between two blocks of ovens, there are two
discharge chutes, one on each side of the larry. The outer part
of the chute c is hinged to the fixed part b so that it may be drawn
up by means of the chain d' and wheel e and thus stop the coal
from running down the chute. The larry hopper and chutes are
supported by a metal framework that rests upon four wheels,
each pair of wheels being provided with springs in connection with
the journal-boxes. The larry shown is electrically operated by a
motor / that transmits the motion to the axle g by means of the
gearing h, i. The current is taken from overhead wire through
the trolley pole /.

The equipment of many larries consists of a standard railway
motor of the enclosed type mounted on one of the axles. The
motor, controller, and trolley may be applied to larries at present
drawn by animal power, it being unnecessary to design a special
larry 'adapted for the electrical equipment. The control is so
perfect that when about to discharge its load into the ovens, the
larry may be moved in either direction literally "an inch at a
time," and a much higher speed is possible than with horses or
mules. The result is a surprising saving in time in hauling from
and returning to the tipple, and in discharging the coal at* the
ovens. The trolley or third-rail system, preferably the latter,
may be used to convey the power to the motor, and the approaches
to the ovens may be much more cheaply constructed, as it is
unnecessary to provide a path for the horses or mules.

One electrically equipped larry with its operator will easily
do the work of two mule larries with their drivers, and when the
conditions permit, the electric larry may supply the motive power
for other larries, which, operated as trailers, may be dropped at
the proper places, having been loaded at the tipple, and picked up
on the return, in the meantime having discharged their loads into
the ovens. The increased adoption of electric mining locomotives
and electric . motors for driving pumps, hoists, car conveyers,
blowers, etc. should be considered in connection with the instal-
lation of a dynamo for the operation of coke larries, but even if
the conditions are such as to debar other applications of electricity,
the investment will show a very good return. At many mines,
generating plants are already installed, in which cases the addi-
tional investment would be very small indeed, and the saving in
cost of operation would soon pay for the electrical equipment of
the larry.

Attention should also be given to facilitating the disposal of
the waste products of ashes and coke dust, as these elements
accumulate largely, even in a plant of moderate size. The water
supply should be pure and the quantity ample at all seasons of
the year, with a medium pressure to afford a full supply of water
and prevent wear to the hose or injury to the brickwork of the

364

TREATISE ON COKE

ovens by an overpressure in the water discharge. In retort coke
ovens, where the coke is cooled on the outside of the oven, the
regulation of pressure in the water supply would only refer to the
wear on the connecting hose.

The following plans of the location of beehive and retort-coke-
oven plants are given to illustrate the salient elements to be
secured in laying out new works. They are not designed to convey
the idea of perfectness, put to indicate the means of doing the best
with the topography of the locality in which the ovens are to be built.

The Morrell plant in the Connellsville region illustrates the
methods of locating a group of four banks of coke ovens, each
bank containing 100 beehive ovens. This plant was constructed in
1880 by the Cambria Iron Company, of Johnstown, Pennsylvania.

Fig. 2 shows the general location of ovens, tipples, bins, and

FIG. 2. MORRELL COKE WORKS, CAMBRIA IRON Co.

a, Morrell slope; b, man way; c, car shop; d, stable; e, office; f, coal pile; g, air-shaft;
h, boiler house; *', engine house; /, blacksmith shop; k, 400 coke-ovens; s, railroad sidings.

railroad sidings. In locating at this place, it was found necessary
to open the mine by a slope a driven down the coal seam, which
is 8 feet thick and has an inclination or dip of 5|° to the north-
west. The coal is raised by extending the plane of the slope until
it attains an elevation of about 40 feet above the level of the tops
of the coke ovens.

The beehive coke ovens k are located in four parallel banks,
each of which is 700 feet long. Each bank of ovens has its flank-
ing wharves. These wharves afford ample space for drawing the
coke from the ovens and loading it on railroad cars. The wharves
are 25 feet wide and 7 feet high.

The ground on which these ovens have been located has a
gentle inclination eastwards, with sufficient descent to enable rail-
road cars and charging larries to be moved down grade by gravity.
The railroad tracks have been arranged so as to afford ample room
for receiving empty coke cars at the upper or west end of ovens,
and to permit the shifting of the loaded cars below the ovens.

TREATISE ON COKE

365

No locomotive power is used at this plant. A man shifts the
railroad cars from the upper sidings and places them at points
along the wharves for loading with coke. When loaded they are
shifted down to the" sidings below the lower
end of the coke ovens.

The coal bins, Fig. 3, are constructed
of heavy framed timbers, with white-oak
plank lining. Each bin holds from 300 to
400 tons of coal. There is one bin, with a
double line of hoppers, to each bank of
100 ovens. These coal-storage bins afford
ample supplies, so that the ovens can be
charged promptly after the coke has been
drawn out.

The coal is brought from the mine to
the platform along the front of these bins,
and is there dumped into any of the com-
partments in the usual manner. Horses
or mules are used in the movements of
the mine cars from the head of the slope
plane to these bins. This arrangement has

FIG. 3. COAL-STORAGE BIN

been found to work with economy.
A device consisting of an endless
wire rope, with grip, might be
used with economy for this work
of delivering loaded cars and
returning the empty ones to head
of plane ; or, better still, electrical
power might be employed.

The water supply comes from
the Youghiogheny River. It is
pumped to an elevation affording
sufficient head to supply the
ovens and the tenement houses
at this and the Wheeler plants.

No. 3 Plant, H. C. Frick Coke
Company. — Fig. 4 will convey a
correct conception of the general
plan of location of the large
coking plant constructed by the
a, Fan and air-shaft; 6, shops; c, coal bins; Leiscnring interests under the
h' vuiige*' engine; f> boilers; g' coke ovens; name of the Connellsville Coke

and Coal Company. It is now
owned and operated by the H. C. Frick Coke Company.

It will be seen by Fig. 4 that these ovens g, g were located in
two curved wings on either side of the coal bins c and shaft d, up
the gentle valley threaded by the Pennsylvania railroad and the

FIG. 4. PLAN OP H. C. FRICK COKE
COMPANY'S No. 3 COKE PLANT

366

TREATISE ON COKE

sidings for this large plant of coke ovens. The ovens are charged
in the usual way, a small locomotive being used in handling the
coal larries to the several banks of ovens. This secures com-
mendable despatch in this department of the work. The larry
tracks are between the double rows of ovens. The side chutes to
these charging larries can be seen in Fig. 5.

The wharves are ample, and the whole arrangement, for each
division of labor, very complete.

The elevation, Fig. 5, showing details of head-house and bins
affords very complete details of these constructions for a central
supply of coal for charging the ovens.

FIG. 5. HEAD-HOUSE AND BINS, H. C. PRICK COAL COMPANY'S No. 3 COKE PLANT

The only suggestion that occurs on the line of security against
fire at this plant is that the head-house over the deep shaft would
be safer from the danger of fire if constructed mainly of iron.

The burning of a head-house causes immediate stoppage of
the coke works, with interruption to coke shipments and serious
financial loss.

Oliver Plant. — Messrs. Wilkins and Davison, Engineers, Pitts-
burg, Pennsylvania, have kindly furnished plans, Fig. 6, of the two
very complete coking plants of the Messrs. Oliver, of Pittsburg,
located near Uniontown, in the Connellsville coke region.

The whole arrangement of these plants with their coal mines
and bin storage supplies affords excellent examples of wise har-
monies in securing economical and safe conditions to both the
mines and coke ovens.

The following able paper by Mr. Fred C. Keighley, general
superintendent of the Oliver Coke Works, will afford much valuable
matter on the location, size of plant, with an outlook as to the
requirements of the works to supply special markets and other

367

368

TREATISE ON COKE

related conditions. It also affords many practical suggestions on
these elementary requirements in the order of economy and facility
of operations.

Plant No. 1 consists of 300 beehive ovens, in two slightly curved
lines, to conform to the topography of the ground, securing desir-
able gradients for railroad sidings and larry tracks. One of these
banks of coke ovens is located in a line of single ovens 1,400 feet
long, containing 100 ovens. The second line, of about the same
length, consists of a bank of a double row of ovens, containing
200 ovens.

The railroad tracks and sidings are ample and well located to
afford the necessary facilities for handling the output of coke.

FIG. 7. COKE OVEN PLANT (300 OVENS). PLANT No. 1, OLIVER COKE WORKS, REDSTONE

JUNCTION, PENNSYLVANIA

The ovens and railroad tracks are on gradients of 1 foot per 100
feet, descending with the tonnage. The ovens are 12 feet 3 inches
in diameter. This plant was completed early in 1892; since that
time it has been increased to 1,208 ovens.

The locations of the shaft, engine house, and coal bin can be
seen on the plan. They were located to secure the utmost economy
in the manufacture of coke. Fig. 7 shows some of the ovens in
process of building.

Plant No. 2 has been located in three double banks of coke
ovens. Each bank is 825 feet long and contains 120 coke ovens,
making in all at this plant 360 ovens. The compact location of
these ovens, with the close relations of shaft and coal bins to the
ovens evidence careful work in the plans.

TREATISE ON COKE

369

The railroad sidings are well located for convenience. The
railroad cars require some extra handling at this plant, as the
railroad connections are confined to one end of the ovens.

At these works, the shafts to the coal are about 415 feet deep.

Danger from fire has been guarded against at these works
by constructing the head-frames of shafts of steel covered with
corrugated iron, Figs. 8 and 10. The coal-storage bins have been
constructed with similar materials and the engine houses of brick
with iron roofs. It is claimed that these fireproof structures are
the first of their kind introduced into the Connellsville coke region.
This introduction, in the lines of safety to life and true economy
in assuring continuous work, is very commendable. The water
supply is secured from the Youghiogheny River, 10 miles distant.

COKE MAKING FOR PROFIT*

A plant of more than 300 coke ovens becomes unwieldy; and
when the ovens are less in number than 300, the fixed charges are
apt to be high. A man can manage two 300-oven plants, if not

FIG. 8. HEAD-FRAME AND ENGINE HOUSE, PLANT No. 1, OLIVER COKE WORKS,
REDSTONE JUNCTION, PENNSYLVANIA

too far apart, with more ease than one 600-oven plant, and it
takes as many officials to operate a 600-oven plant as to operate
two 300-oven plants. So, if a large number of ovens is desired,
the best plan is to divide them, as nearly as practicable, into
300-oven plants. This is not only my view of the matter, but
the view of the more experienced coke men of the Connellsville

*Fred C. Keighley, in American Manufacturer.

370

TREATISE ON COKE

TREATISE ON COKE 371

coke region. So, in what I write hereafter, I shall make my obser-
vations and suggestions mainly with reference to a plant of that
magnitude. However, there are many people who will not, or
cannot, build a plant of 300 ovens, and they will naturally ask how
they are to determine how many ovens to build. This is a some-
what difficult ' matter to decide, as there are many things to con-
sider; yet there are certain conditions that in a degree indicate
what is to be done. For instance, if the manufacture of coke for
the blast-furnace trade is contemplated, then the extent of that
kind of trade to be had will fix the number of ovens to be built.

Modern blast furnaces consume all the way from 300 to 600 tons
of coke per day, and as many furnace men object to the use of
mixed coke, owing to its interfering with regular or uniform work,
to build less than sufficient ovens to run one furnace would cer-
tainly be fatal to the success of the venture. Generally speaking,
12-foot beehive coke ovens will yield 2 tons of coke per oven per
day; so that a blast furnace of 300 tons of coke per day capacity,
will require 2,100 tons of coke per week of 7 days. A coke-oven
week is but 6 days; therefore, the quantity required from the ovens
will be 350 tons per day; this divided by 2 will give us 175 coke
ovens, the number required. A two 300-ton furnace capacity
plant would require 350 ovens, and so on. If foundry trade were
to be supplied, instead of furnace trade, the number of ovens
required would be determined in an altogether different manner;
and I know of no better or safer way of determining it than by
the coal acreage owned or controlled by the prospective coke
operators.

An 8-foot seam of Connellsville coal will yield fully 12,000 tons
of coal per acre, if free from faults and skilfully mined, and this
in turn, if properly manipulated, will yield 8,000 tons of coke.
Taking 600 tons as the work of a 12-foot beehive oven for 1 year,
an acre of coal will keep one coke oven running steadily for 13 J
years — allowing for dull trade, strikes, car shortages, and repairs,
we might safely put it 15 years.

If the coal to be operated is drift coal and comparatively cheap
to develop and equip, 15 years will be a safe life for the plant;
but should the coal be below water level, necessitating the instal-
ment of costly machinery and pumps, and the sinking expenses
be heavy, then 30 years will be none too great a period to allow to
get out all there is in the equipment. For instance, a property of
150 acres of drift coal will require 150 coke ovens to make what I
term a fairly well-proportioned plant; but a slope or shaft coal
property of over 100 feet and up to 200 feet in perpendicular
depth, to get the best attainable results, should be of such acreage
as to sustain at least 200 coke ovens for 30 years. A 200-oven plant
on such a basis will require at least 400 acres of coal. Deeper
coal would require more coke ovens and a correspondingly greater
acreage to make it a well-balanced venture. Take the following

372

TREATISE ON COKE

FIG. 10. HEAD-FRAME AND COAL BIN AT OLIVER No. 3 PLANT

SOS

17303— ix

FIG. 11. PLAN OF AMERICAN COAL AND COK

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MPANY'S PI-ANT AT EDENBORN, PENNSYLVANIA

I * oA

TREATISE ON COKE 373

figures as factors : One coke oven yields 600 tons of coke per year.
One acre of 8-foot Connellsville coal yields 12,000 tons of coal;
12,000 tons of coal makes 8,000 tons of coke. One acre of 8-foot
coal will run one oven 15 years. Life of a drift plant is 15 years;
life of a 100-foot sinking, 30 years. One acre of coal for each oven
at a drift plant. Two acres of coal for each oven at a 100- to 200-
foot depth. Twice as many coke ovens on a 200- to 400-foot
depth as on a 100- to 200-foot depth, and a correspondingly increased
acreage. In very large tracts of coal land, a correspondingly
large number of ovens in plants of 300 ovens to each establishment.

With this data as a basis for calculation, any one of ordinary
ability should be able to determine the number of ovens required
on a given acreage, or the acreage required for a given number of
ovens. Of course, the kind of trade expected must not be over-
looked in making up the verdict.

Small coke plants are generally arranged on a single line of bank
ovens, but the larger plants are made up of several rows of bank
and block ovens, in order to secure compactness, etc. The arrange-
ment of the ovens is generally governed by the location that is
available. There are very few natural oven locations, and often,
even when a good oven location is found, it cannot be used because
it does not also afford a good coal mine site, or the grades are
such that it cannot be reached by railroad with a profitable grade.
It would be out of the question to lay down any rules as to the
arrangement of the ovens; so what I have to say relative to the
location of the ovens, etc., must be taken in a general way and
with due consideration.

Beehive bank ovens when located parallel with or to moder-
ately rising ground where the rock does not crop out above the
floor or seat of the contemplated oven, and the soil is of the proper
character and solidity and can be well drained, make the best
and cheapest of all beehive-oven locations — best, because the oven
can be located on naturally solid ground, affording a firm founda-
tion at small cost, and the ground rising behind them affords not
only a storage battery for heat, but also allows the oven to expand
backwards instead of forwards, and thus relieves the oven and
retaining walls from excessive strains. Another advantage with
such a location is that all the ovens face the pure air, if all in one
string, which is quite an advantage, as coke ovens that face the
air always make more and, unless in stormy weather, brighter coke.

Bank ovens are the cheapest to build, for the reason that the
side cut for the ovens also makes the filling for the coke yard, or
wharf, while the dirt for filling around the ovens can be easily and
cheaply obtained from the rising ground behind; however, I would
not advise that the whole of the 300 ovens be located on a single
line, for the following reasons, viz.: First, because it would not be
the most economical way of charging the ovens, owing to the long
distance to be traveled over; second, the long distance traveled

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ffi.S

374

TREATISE ON COKE 375

over would necessitate an increase of speed for the charging
equipment, which, in turn, would not only cause excessive vibra-
tion, which would shorten the life of the oven, but would also
increase liability to accident, excessive strains to the larry tracks,
and more wear and tear to the equipment; third, the wheel on the
coke yard would be longer than desirable for the coke drawers;
and fourth, the length of the larry tracks on the ovens, and the
length of the sidings for the railroad cars would be very much
greater than desirable, convenient, or economical, and would fur-
ther necessitate many cuts or breaks in the ovens for ways for
ash carts, etc. In view of the above important factors, the plant,
if all bank ovens, should consist of two rows of ovens of 150 each,
the said rows facing each other, with the railroad siding running
down between the respective coke yards.

American Coke Company's Plant. — The coking plant of the
American Coke Company, Fig. 11, is situated at the Edenborn
mine in Fayette County, Pennsylvania, in the Connellsville region.
It consists of a plant of 500 beehive coke ovens, arranged in four
parallel banks or batteries, with wharves, railroad sidings, reser-
voir containing ample supplies of water, and all necessary appli-
ances for the successful working of this plant.

The dwelling houses, as shown on this plan, have been neatly
finished, affording comfortable homes to the miners, coke drawers,
and other workmen. The whole arrangement of the several parts
affords evidence of a carefully considered plan, securing harmony
of its parts and economy in all its operations.

The Hostetter Connellsville Coke Company's works consist of
two coke plants, the Whitney and Lippincott, located in the north-
ern section of the Connellsville field, about £ mile apart, on the
Latrobe branch of the main line of the Pennsylvania Railroad.

Both these works have been located in little valleys on small
streams, tributaries of Nine Mile and Loyalhanna creeks. They
are very nearly alike in their plans of location and number of coke
ovens. The method of location of the Lippincott plant, Fig. 12,
will serve to illustrate the general plan of both these works. It
has not been considered necessary to add the plan of the location
of the Whitney works.

The Lippincott coke plant consists of 305 beehive coke ovens,
which are 12 feet in diameter and 7 feet high to crown of the dome.
The ovens have been located in two lines, along the south bank
of the Nine Mile Run, conforming in their alinement with the con-
tour of the ground at this place. The northern line of ovens is
composed of a bank of a double row of ovens; the southern bank
consists of a single line of ovens.

The plan, Fig. 12, exhibits the arrangement of the railroad
tracks and sidings for the supply of coke cars for this trade. Ample

376 TREATISE ON COKE

room has been provided for storing empty coke cars at the upper, or
west, end of the plant, with full space at the lower, or east, end for
making up trains of loaded coke cars for transportation to market.

The coal cars are drawn up the slope from the mine by the
winding engine and placed on the long coal bin, where they are
unloaded rapidly into the hoppers underneath. The larries for
charging the coke ovens are loaded under these hoppers.

The mine cars are not unhitched from the wire haulage cable,
but are unloaded into this long bin by opening the bottom slides
in these coal cars. A train of these loaded mine cars consists of
ten cars, containing 45 bushels in each car, nearly 2 tons of coal.
Immediately on their being unloaded, they are quickly lowered
into the mine and unhitched from the cable, which is then hitched
to a loaded train of cars.

The larries for charging the coke ovens are handled by a 7-ton
locomotive operated on standard-gauge tracks. The gradients
of railroad and larry tracks descend eastward, affording nearly
balanced gravity lines for these operations.

The office and store is located at the west end of the works,
where the incoming and outgoing cars pass.

Arrangements have been made at both plants for shipping
coal when found necessary to do so.

The slopes into the mines are 2,600 to 2,800 feet long. They
have been driven in the large coal seam, which has here an incli-
nation westwards of 6^ feet per 100 feet.

These works were constructed during the years 1889-90, under
the plans and supervision of Mr. John McFayden, the general
manager of the company.

When in full operation, these works can produce about 1,200
tons of coke per day. The main effort in these locations was to
reduce the cost of the labor of making coke to a minimum. It is
evident that this has been secured as far as the plan of extended
oven lines will permit. It is worthy of future consideration, in
locating coke ovens, whether more compact lines, like those at
Morrell and Oliver No. 2, will afford more labor economy in the
section of the work in charging the ovens.

The Joseph Wharton coke plant. Fig. 13, illustrates the general
plan of the Wharton Coke Works, situated at Coral Station on the
Indiana branch of the Pennsylvania Railroad, in Indiana County,
Pennsylvania. It consists of 300 modern beehive coke ovens,
located in two curved sections on either slope of the valley of a
little stream, a tributary to the large Two Lick Creek, securing
advantageous gradients for the coke ovens, as well as for the rail-
road sidings and larry service. The water reservoir is located in
the gentle valley of this small stream, and is of liberal dimensions
to afford at all times an ample supply of water for all uses at
their works. The water is mainly pumped from the nearby Two
Lick Creek.

xi --f.or.-r

17303— ix

FIG. 13. PLAN OP JOSEPH WHARTON C<

' .ANT AT CORAL, INDIANA COUNTY, PENNSYLVANIA

TREATISE ON COKE

377

The mine from which the coal is obtained is shown on this
plan, with its main workings, now being rapidly extended to meet
the daily needs, which, when all the ovens are in blast, will be 1,100
to 1,200 tons per day. The coal lands of this plant consist of
3,000 to 4,000 acres, containing all the beds of the lower coal
measures, in the aggregate about 19 feet of coal. The mine works
are in the upper Freeport coal bed (E), here 5 feet 9 inches thick
with a slate parting.

The coal is broken to small sizes and washed in preparation
for coking. The coal washer is of the recent design of Stein and
Boericke, of Primos, Delaware County, Pennsylvania, having ample

FIG. 14. COAL-STORAGE RECEIVER

capacity to meet the coke-oven supply. The broken coal is not
classified, but is treated in three continuous washer pans, the tailings
receiving an additional cleaning under conditions to meet its needs.

The washed coal is elevated into a large coal-storage receiver,
Fig. 14, where it is allowed sufficient time to part with its water.
The receiver holds about 3,000 tons of washed coal for the ovens.
As only about 1,100 tons per day are required for charging the
ovens, it will be seen that the coal has over 60 hours in which to
dry, prior to its being charged into the ovens.

Fig. 14 will exhibit the general arrangement of the coal-storage
receiver, with the arrangements for lifting the coal and loading
it into larries.

378

TREATISE ON COKE

±1

Exhausting

and

Condensing
Apparatus

17303— ix

FIG. 16. ARRANGEMENT OF <

a, Coal dump; b, elevator to feed c; c, disintegrator; d, elevator to storage tower; e, coal-
*, air inlet to ovens; /, charging holes for coal; k, gas flue; /, chimney to be used if gases are n
ram (pushing machine) travels parallel with ovens; o, coke discharge side; q, tracks for chargii

[)VENS WITH CRUSHER. BERNARD'S SYSTEM

t tower; f, engine; g, boiler heated by waste gases; h, twenty retort coke ovens without saving of by-products;
:1 for boiler heating; m, chimney to be used if gases are used for boiler heating; n, machine side of ovens where
•ies; r, tracks for windlass for raising doors of ovens; s, water supply.

TREATISE ON COKE 379

The plan of the coke ovens is of the most modern design.
Figs. 7 and 8, Chapter V, show the plan, section, and all details.
In the front of this oven a double brick arch is seen above the
shaped firebrick arch over the oven door. These ovens have been
constructed of the best materials and in the most substantial
manner, under the general superintendence of Mr. Harry McCreary,
of Indiana, Pennsylvania.

The coke wharves to these ovens are very wide, so as to store
coke during periods of a deficient supply of railroad cars. They
are faced with permanent masonry retaining walls of increased
height to meet the needs of modern steel coke cars.

The miners' hamlet is a model of neatness and excellent sani-
tary conditions. The whole plant is operated by steam and
electric power, with the intelligent application of modern labor-
saving machinery. A general view of the plant is shown in Fig. 15.
This plant has been laid out under the general superintendence
of Mr. Harry McCreary, ably assisted by Mr. R. M. Mullen, civil
engineer.

Mr. Joseph Wharton, LL. D., of Philadelphia, has not been
sparing of means in the construction of this excellent coking plant.
It is most complete in all its parts, and should, under intelligent
management, afford satisfactory results in both the quantity and
quality of its product.

Mr. Wharton owns and operates a number of large blast fur-
naces at Wharton, New Jersey. The coke from this and another
coke plant in the Connellsville region goes to these blast furnaces.

RETORT-OVEN PLANTS

The plan and elevation, Fig. 16, show the general requirements
in locating retort coke ovens. It will be seen that the require-
ments in their location differ materially from the location of the
beehive ovens, in the ' wider spaces demanded for the steam
ram or pushing engine for discharging the coke from the retort
ovens. In the above instance, a width of 45 feet is required for
steam connections and pushing engine. In the beehive ovens, the
coke is usually drawn out by manual labor, requiring only 30 feet
of wharf room, while in the retort ovens 40 feet width in wharves
is required on both sides of the ovens.

The plan shows the method of locating a bank of 20 Bernard
coke ovens, with coal dump or hopper for receiving the coking coal
from the mine or railroad cars, with elevators, disintegrator, and
storage tower; all in close relations to the bank of coke ovens. The
coal-storage tower has double hoppers below, through which the
coal is loaded into the charging larry.

The steam boilers are placed at the end of the bank of
ovens, and are usually fired by the gases from the coke ovens;

380 TREATISE ON COKE

but in case of failure of an adequate supply of gas, the defi-
ciency can readily be obtained in coal from the adjoining coal-
storage tower.

The space on the wharf required for discharged coke is, in
this instance, 40 feet wide to receive the charge of coke from the
ovens, which are 30 feet long.

The bank of ovens can be extended to embrace a line of GO
coke ovens. When a greater number is required, parallel banks can
be readily located. If the by-products are to be saved, the neces-
sary exhausting and condensing apparatus can be placed imme-
diately behind the coal-storage tower, in a building set apart for
these uses.

In locating large plants of retort coke ovens in parallel banks,
the exhausting and condensing appliances can be proportioned
to supply two banks of 60 ovens each. A similar application can
be made of the apparatus for treatment of coal, when it may be
found necessary, that is, one apparatus to supply two banks of
coke ovens.

In most cases it is considered prudent to establish duplicate
condensing apparatuses, as any interruption to this part of the work
would produce general disorder.

Steam rams or pushing engines have been constructed under
different plans. Some of these engines carry with them a steam
boiler, while others receive their steam through ingenious arrange-
ments of movable steam pipes from stationary boilers.

The gradients of railroad sidings and charging larry tracks
should be governed by the same principles that are found neces-
sary to economy of work in beehive ovens. In some cases the
retort ovens are located in the immediate neighborhood of the
blast furnaces, and the coke is handled from the former to the lat-
ter in the usual coke barrows. Even in this location, gradients
descending with the tonnage will conduce to facility and economy
of this work.

In the foregoing considerations of the location of plants of
coke ovens, the sites have been contemplated at or quite near the
coal mines. The usual quantity of coal to make 1 ton of coke is
1.5 to 1.7 tons. The economy of locating coke works at the coal
mines is based on the less freight charge on 1 ton of coke, against
the charge on 1.4 or 1.6 tons of coal.

It is quite evident that in most cases this method of locating
the coke ovens at the coal mines is the true policy. It has, how-
ever, some drawbacks. There is usually a loss of 2 or 3 per cent,
in the loading of coke at the ovens and unloading it at the furnaces
or steel works. In the wet and winter seasons it occasionally
receives 2 to 3 per cent, of moisture in the transit. But the loss
in both of these would not compensate for the increased freight
on coal to make coke at the furnaces or steel works, provided that
the freight charges per ton are equal.

TREATISE ON COKE 381

PRODUCTION OF ILLUMINATING GAS FROM COKE OVENS*

The object of this paper is to describe the progress that has
been made in the United States and Canada in recovering illumi-
nating gas from by-product coke ovens. A clear account of this
cannot be given without repeating some of the previous state-
ments published.!

Before entering upon the subject, I cannot resist the tempta-
tion of discussing its bearing upon the vexed smoke problem of
large cities.

The Fuel Supply of Large Cities. — The question of the fuel sup-
ply of large cities is of the greatest importance. Nothwithstanding
this fact, its study has been neglected in a distressing manner.
We still see the large manufacturing cities in Great Britain, as well
as in the United States and other countries, darkened and begrimed
with clouds of smoke and soot resulting from the use of bituminous
coal. The annual expenditure for the maintenance of buildings,
etc. is increased, not to mention the deleterious effect on the
health of the people.

The subject has been discussed by George Beilby in his presi-
dential address before the Society of Chemical Industry. J He
gives the following table:

CONSUMPTION OF COAL IN THE UNITED KINGDOM IN 1898

Coal for the generation of power in industries: LONG TONS

Railways 10,000,000 to 12,000,000

Coasting steamers 6,000,000 to 8,000,000

Mines. 10,000,000 to 11,000,000

Factories 38,000,000 to 40,000,000

Total 71,000,000

*Paper read before the gas section of the Engineering Congress at Glas-
gow by F. Schniewind, Ph. D,

t (a) Professor Hoffmann's extract from Dr. F. Schnie wind's test
report on Dominion coal at Glassport, Pennsylvania, "The Production of
Illuminating Gas in By-Product Coke Ovens " Engineering and Mining
Journal, October 8 and 15, 1898; Progressive Age, 1898, page 575. (6) "The
Everett Coke-Oven Gas Plant," Progressive Age, August 15, and September 1,
1899; January 1, 1900; Journal of Gas Lighting, Vol. LXXIV pages 1,114,
1,176; Vol. LXXV, page 274; Vol. LXXVII, pages 616, 679, 749, *82o!
(c) "Otto-Hoffman Coke-Oven Practice." American Gas Light Journal,
Vol. LXXVII, page 444. (d) "By-Product Coke in the United States"
Iron Age, Vol. LXXVIII, page 14.

JJournal of the Society of Chemical Industry, Vol. XVIII, page 643;
Journal of Gas Lighting, Vol. LXXIV, page 175.

382 TREATISE ON COKE

Coal for the generation of heat in industries: LONG TONS

Blast furnaces 16,000,000 to 18,000,000

Steel and malleable-iron works. . 10,000,000 to 12,000,000

Other metallurgical works 1,000,000 to 2,000,000

Chemical works, potteries, and

glass works 4,000,000 to 0,000,000

Gasworks 13,000,000

Total 51,000,000

Coal for domestic purposes 35,000,000

Coal for the generation of power in industries, as tabulated

on page 381 71,000,000

Total consumption ,,-..; YW->. -. ... 157,000,000

Of this amount of bituminous coal, only a very small percent-
age is subjected to dry distillation, which converts it into smoke-
less coke (see following table) ; the remainder is almost entirely
burned directly, under conditions that are favorable to the pro-
duction of smoke.

COAL SUBJECTED TO DRY DISTILLATION IN THE UNITED
KINGDOM IN 1898

LONG TONS

Gasworks 13,000,000

Blast furnaces 2,000,000

By-product coke ovens 1,250,000

Total 16,250,000

This figure does not include the coal coked in beehive ovens
without the recovery of by-products, which amount is approxi-
mately 12,500,000 long tons. ,

Mr. Beilby suggests two solutions of the smoke problem:
(1) the use of improved appliances for the combustion of the raw
coal, and (2) the transformation of the raw coal into smokeless
fuel by carbonization or gasification.

We are of the opinion that the first method offers only a partial
relief, and, furthermore, that it is a wasteful one, because valuable
products can be recovered from bituminous coal by dry distilla-
tion that are wasted in the direct combustion of raw coal. The
second method, i. e., that of the conversion of the raw coal into a
smokeless fuel by carbonization, seems to us the most rational
and economical solution of the problem. This method has, in the
meantime, developed to a very considerable extent in the United
States. The United Coke and Gas Company, of New York, has
introduced into the United States by-product coke-oven systems
exploited by Dr. C. Otto & Co., of Germany, chiefly the Otto-
Hoffman coke ovens. A large number of these plants have been
erected. In Germany, these plants are operated almost entirely
for the production of metallurgical coke, while the surplus gas is
burned under boilers. A number of the American plants operate

TREATISE ON COKE

383

in the same way, but several of the later plants are designed
for the exclusive manufacture of domestic and railroad coke and
illuminating gas.

A very large proportion of the coal, as given in Mr. Beilby's
table, is consumed in or near large cities, and we believe this coal
should be subjected to a carbonizing process before use. This
would supply to the city at once a cheap smokeless fuel suitable
for practically all purposes. We will show further on that the use
of coke instead of coal would not be coupled with a great expense
to the fuel consumer. By the erection of large carbonizing works
near or in large cities, the smoke problem would find its ready
solution; and at the same time, a great saving, from a national
economic point of view, would result from the recovery of the
valuable by-products and gas.

How urgent the demand for smokeless fuels has become is
plainly shown by the fuel statistics of some of the larger American
cities. In the United States, anthracite is found in a small dis-
trict in Pennsylvania, while bituminous coal is scattered over
almost all the states east of the Mississippi. Notwithstanding the
close proximity of the bituminous coal fields to some of the larger
cities, enormous quantities of anthracite are brought to them from
a great distance, and consequently at great expense.

The following table demonstrates how enormous the demand
for smokeless fuel has become, and furthermore, that a great
premium is paid for the smokeless character of the fuel. The
prospects are, therefore, encouraging for the erection of carbonizing
plants near large cities.

FUEL STATISTICS OF SOME AMERICAN CITIES FOR 1900

Bituminous Coal

Anthracite

Quantity

Used
Net Tons

Price Per
Net Ton
Dollars

Quantity
Used
Net Tons

Price Per
Net Ton
Dollars

New York

1,700,000
2,050,000
7,000,000

2. 50 to 3.50
2.00 to 3.00
2.50 to 3.50
2.00 to 3.00

3,300,000
1,950,000
1,600,000

3.50 to 4.00
4.00 to 4.50
4.00 to 5.00
5.00 to 6.00

Philadelphia

Boston

Chicago

NOTE. — The total amount of bituminous coal and anthracite for domes-
tic consumption and the supply of steamers in New York and adjacent cities
belonging to the port of New York is estimated at 15,000,000 net tons.

In order to facilitate an understanding of the more detailed
account of the process, a general description of the combined coke-
oven and gas process is first given, comparing it at the same time
with ordinary gas-retort practice.

384 TREATISE ON COKE

The coke ovens have a charging capacity of 16,000 pounds of
coal, which is all carbonized in 24 hours and less. Ordinary gas
retorts have a charging capacity of only 300 to 400 pounds, which
is carbonized in about 4 hours.

On account of the increased charge, all the operations around
the coke ovens are performed by machinery, which results in a
saving of labor per ton carbonized, as compared with the present
coal-gas system.

On account of the larger charges and the peculiar construction
of the coke ovens, a far better coke is produced, as compared with
that obtained in ordinary small gas retorts. The coke oven yields,
if required, a coke that satisfactorily sustains the burden of a
modern large-sized blast furnace. It is consequently of much
higher value than gasworks coke. The coke oven may also produce
domestic coke far superior to gasworks coke.

The coke oven, like the ordinary gas retort, saves tar and
ammonia, and eventually several additional by-products. The
coke oven yields, however, a higher percentage and a better quality
of these products than the gas retort.

The ordinary gas retort produces the heat necessary for car-
bonizing the coal by burning a part of the resulting coke under
the benches. In the coke-oven process, all the coke is saved,
while a part of the resulting gas is burned under the ovens.

. THE EVERETT COKE-OVEN GAS PLANT*

The property consists of about 288 acres of land in Everett and
Chelsea, Massachusetts. This is largely tidal marsh land, but a
ridge of gravel extends from Beacham Street, Fig. 17, to the point
between Mystic and Island End rivers. This gave excellent
material for filling and also for making concrete. The character
of the ground necessitated a great deal of piling. There was
driven a total of about 35,000 piles, and immediately upon these
piles a cap of concrete was put.

The present plant of 400 ovens occupies but a small part of
the property. The design of the plant permits of an increase to
1,200 ovens, the erection of which number is ultimately contem-
plated. The next set of 400 ovens will be located between the
present plant and the wharf, and the third between the present
plant and the purifying house.

Coal-Handling Plant. — The coal employed is washed Cape
Breton slack coal received from the Dominion Coal Company.
The coal-handling plant was designed by L. J. Hirt, the chief
engineer of the New England Gas and Coke Company, and is on
the rope-haulage principle.

*By Dr. F. Schniewind, in Progressive Age for August 15, 1899.

TREATISE ON COKE

385

The steamers land the coal on the company's wharf, Fig. 17.
On top of the 6,000-ton coal bin A, three hoisting towers are
provided with so-called "clam-shell" grab buckets of 1.5 tons
capacity. The speed of unloading is about 150 to 200 tons per

FIG. 17. PLAN OF WORKS, NEW ENGLAND GAS AND COKE COMPANY

tower per hour from the full cargo. During the "trimming" of
the coal the capacity is of course reduced.

Underneath the bin are three tracks provided for coal larries,
or cars holding about 2.5 tons each. There are thirty of these
larries. The loaded larries run by gravity to the north end of
bin A, where they are connected with the cable, which carries

386

TREATISE ON COKE 387

them to the four coal bins 3, 4, ®> 1 (of & capacity of 2,000 tons
each) at the ovens, and into the large storage yard F. The latter
provides for the storage of 80,000 tons of coal and consists of a
wooden trestle from which the coal can be dumped upon the ground.
From this pile, a movable double tower can pick up the coal on
either side of the trestle and transfer it back to the coal larries,
which then convey it to the oven bins.

It is during a short period in March or April only that the
Cape Breton harbors (Louisburg and Sidney), from which the coal
is shipped, are icebound, and consequently with the beginning of
winter sufficient coal will be accumulated to tide the works over
this period.

At present, the motive power for the coal towers on top of the
storage bin ^4, as also for the cable-driving machinery, is steam,
but it is the intention to operate these by electricity. All the bins
are of steel with wooden lining.

The coke ovens are arranged in eight groups, or batteries, of
50 each, B1-B8, Fig. 17. Two of these groups, 100 ovens, form
one working unit and are supplied with coal from one bin. Bat-
teries B1,B2, B3, B4 are connected with stack M, and B5, B6, B7, B8
with stack N. The batteries are erected on high foundations for
two reasons, viz. : first, to bring the bottom of all flues above
extreme high water, and second, to admit of dumping the coke
into the highest railroad cars without another lifting.

At present, batteries Bl and B3 are in operation, and battery
B2 is being heated by means of some surplus gas from batteries
Bl and B3.

Capacity. — The retorts are 33 feet long, nearly 6 feet high, and
18 inches average width, and have a capacity of 6 net tons coal
per charge. They are of the Otto-Hoffman type with several
modifications to adapt them to the present requirements.

Firebrick. — Unusual care has been taken in truing the brick
used for erecting the walls, and so successful have been these
efforts that no allowance had to be made for joints. The impor-
tance of obtaining gas-tight walls is manifest. As in these works
the gas is of more importance than usual with coke ovens; this
care was wise.

It has been found that the average American firebrick is far
more refractory than the European -coke-oven brick, but never-
theless even the best brands are generally not suitable for retort
coke ovens. The reason is the considerable shrinkage of these
American brick when exposed to high heat.

The strains on coke-oven brick are very severe, as the walls
in the bottom flues are subjected to very high, continuous tem-
peratures from all sides, while again in another part (the retort
proper) the brick are subject to sudden cooling by the cold and
sometimes wet coal charges and to the mechanical abrasion of
the coke charge when pushed out.

TREATISE ON COKE 389

The first Otto-Hoffman plants, when built in this country, viz.,
at Cambria Steel Company, Johnstown, and the Pittsburg Gas
and Coke Company, Glassport, Pennsylvania, experienced consider-
able trouble on this account. But the problem had to be solved,
as the introduction of the retort oven into the United States
depended on the securing of suitable domestic firebrick; and it
may be said that by properly using various refractory materials
the problem has been solved so successfully that GO ovens at
Johnstown, now in continuous operation for 2 years, do not show
the slightest cracks or deviations from their original dimensions.

Charging. — The coal charge is brought from the bin to the
ovens by means of an electric charging machine (not shown in the
illustrations) and filled into the retort through three charging
holes in the roof, a, a1? a2, Fig. 19. The coal is then leveled by
introducing scrapers through small holes b and bf in the two
doors, c and c' . When this charge is level, holes b and bf are
closed and luted, and the same is done with the three charging
holes, a, a1? a2-

Removal of Gases. — The evolution of gases and vapors has at
once commenced with the charging of the coal. By raising the
drop valve d, the products of distillation are permitted to escape
through standpipe e into the gas-collecting main /. It should be
mentioned that this is a dry main and not a hydraulic main.
The mains are kept free of pitch by a tar flushing system.

The Coking Time. — The charge of coal, 6 net tons, is carbon-
ized in from 24 to 30 hours. This time varies from several causes,
among which is an important one — the character of the coke that
it is intended to produce. If we wait until the last traces of vola-
tile matter are expelled, then we will produce a very hard coke,
but will require a long coking time. If, on the other hand, we
push the oven before the last traces of volatile matter are driven
off, then the coke is softer and better suited for domestic and
boiler-firing purposes and the coking time is materially reduced.

In the beginning, 60 ovens were pushed per day out of the 100
in operation. With the growing demand for coke, this number
was increased to 80 ovens. This corresponds to a coking time of
30 hours. But with this modus operandi a considerable number,
from 20 to 30 ovens, are always "around," i. e., ready to be pushed.
Thus, the coking could easily be reduced to 24 hours, and will be
shortly with the constantly increasing orders for coke.

Discharging of the Coke. — When the oven has ceased to give
off gas, -which can be ascertained through small holes in the doors,
the valve df ', Fig. 19, is closed and thus the oven is disconnected
from the poor gas main /'. The charging-hole covers a, alt a2
are then opened and the oven is ready for the coke pusher.

In order to distribute the fresh charges over the entire battery,
a regular rotation of pushing the ovens has been established.
Beginning, for instance, with oven No. 1 at one end of the battery,

390 TREATISE ON COKE

the next ovens are 11, 21, 31, and 41; after this, ovens Nos. 6, 16,
26, 36, and 46 are pushed. This is followed throughout the entire
100 ovens. It is apparent that such an arrangement makes it
impossible to charge two adjoining ovens in short succession.

The electric coke pusher /, Fig. 19, is then brought opposite
the oven ready to be pushed. The doors at both ends, c and cf,
are hoisted by means of electric contrivances, situated at the end
of each battery. Rollers u are provided over each door, on
which a long bar is resting, which connects with the electric door
hoist. Whenever a chain is attached to the door and to this bar
and the bar moved sidewise, the door will be raised.

The electric coke pusher / consists of a long rack and pinion
that forces through the oven a shield k bearing against the coke
charge. Thus, the entire charge of coke is forced out toward the
coke side. In order to facilitate the moving of the charge, the
oven is a little wider at the discharge end than at the pusher side.
The hot coke then falls into the electric coke-loading machine y.
A jet of water is thrown upon the coke immediately upon its
leaving the oven.

The coke loader consists of a long, inclined pan w capable of
holding the entire charge of about 4.5 net tons of coke. In order to
obtain a good distribution of the coke in this pan, the entire machine
is moved sidewise while the coke is coming out. As soon as the
charge is on the pan, this travels with its hot charge to one side,
and a second loading machine finishes the operations at the oven.
Thus, the men are not exposed to the high heat from the glowing
coke. The hot charge then receives another quenching. When
the coke is fully cooled, partly by water and partly by the air,
the pan is tilted and the gates x are opened, which allows the
entire coke charge to slide into the railroad cars g.

Immediately after the coke has been pushed out, the pusher
bar is withdrawn and the doors c and c' are lowered. The doors
are forced close against the brickwork of the oven by means of
bars, held in buckstaves v between the ovens, and wedges. After
this the doors are sealed hermetically by throwing loam around
the same, and the oven is ready for another charge. The entire
operation of discharging the oven and recharging the same is com-
pleted in about 10 to 12 minutes.

Disposal of the Coke. — All the coke coming from the ovens is
first loaded into railroad cars. The New England Gas and Coke
Company owns 150 cars, which are of improved open top-rack
type. The capacity of these cars is about 22 to 25 tons. Provi-
sions are also made to load the coke into box cars. The coke
coming from the ovens consists chiefly of columnar pieces about
9 inches long. With these pieces is mixed a small percentage of
smaller pieces. This coke is called "run-of-oven coke," and is
shipped directly for use under boilers, locomotives, for metallur-
gical purposes, etc.

TREATISE ON COKE 391

If the coke is to be used for domestic purposes, the railroad cars
are switched to a coke crusher by which it is broken into different
sizes and screened. The different sizes are collected in separate
bins, from which they are drawn into railroad cars for shipment.
The railroad cars can be shifted directly on to lighters that trans-
fer the coke to any of the large coal yards, etc. in Boston. Pro-
visions are also being made to load the coke in bulk into steamers
and sailboats. There is, furthermore, in construction a large
storage yard capable of holding about 50,000 tons of coke for the
winter trade, and a movable crane is being erected, which has a
span of 200 feet and travels a distance of 600 feet, thus covering
a total area of 120,000 square feet. This crane will either load
the coke from the cars on to the storage pile, without breaking it
by a high drop, or will load it back from the pile into the cars.

CHAPTER X

GENERAL CONCLUSIONS ON THE WORK, COST, AND PROD-
UCTS OF THE SEVERAL TYPES OF COKE OVENS

Adaptability of Different Ovens in the Several Coal Fields. — In

the eastern and middle coal fields of the United States, the areas
of the sections of the coal measures whose beds are adapted for
the manufacture of coke, in greater and less degrees, have been
generally well defined. Much has yet to be done in the great
far West in the further development of its coal fields, and
in determining the special localities affording coal suitable for
making coke.

So far as our present knowledge extends, there are at present
four well-known groups or sections of coking coals. These areas
of coking coals are found in meridional strips, conforming in their
general southwestward courses to the crest-line trends of the
Appalachian mountain chains. They are found in the following
order from west to east:

Section 1. The several types of coals very rich in bituminous
matter, affording a light coke with a highly inflated physical
structure, and not regarded as a desirable fuel for metallurgical
purposes. This class of coals contains from 35 to 40 per cent, of
volatile matter.

Some efforts have been made to coke these coals; evidently the
progress thus far has not been quite satisfactory. Treatment in
the horizontal types of ovens appears to have produced the best
results; but the coke is usually spongy, inheriting an inflated phys-
ical structure and lacking the hardness of body so essential to a
good metallurgical fuel. It is coming to be understood that this
class of rich bituminous coals requires a moderate oven heat to
secure the best possible coke.

A serious difficulty has embarrassed the efforts hitherto made
to produce clean metallurgical coke from these coals, from the
rather large percentage of sulphur inherited by most of them.
This sulphur is found generally interleaved in the bedding planes
of the coal, as well as scattered through it in thin scales. The
attenuated condition of this sulphur admixture constitutes the
chief difficulty in efforts to reduce or remove it by the ordinary
processes of disintegration and washing. A practical plan for

392

TREATISE ON COKE 393

reducing this thinly mingled sulphur from these western coals
would enable a coke to be made from them that could be used
in whole or in part of blast-furnace operations.

A broad horizontal oven, with flues under its floor, heated with
returned gas evolved in coking, and without side flues, would
probably be the best method of reducing the injurious action of
the surplus fusing matter in these coals. This would be a some-
what different application of the meiler or mound principle of
coking coal. It is probable that a mixture of the class of dry
coking coals with these rich bituminous coals would produce a
firm coke. This, however, would involve the additional expense
of freight, with extra care and labor in mixing the coals.

It is important to note that the area of this section of rich
bituminous coal is by far the largest, in fact larger than all the
others together. It follows, therefore, that it presents an inviting
field for further experiment in determining the best type of coke
oven for the successful production of useful coke in this large area
of bituminous coal.

The type of coke oven to produce the best possible coke, with
the saving of by-products, would evidently follow promptly the
success of cleaning the coal for the manufacture of coke.

Section 2. This small section embraces the best qualities of
coals for the manufacture of coke. They contain 25 to 35 per
cent, of volatile matter. The strip is narrow, averaging 3 to 5
miles wide in Southwestern Pennsylvania, located parallel to and
west of the Chestnut Ridge. It constitutes the celebrated Connells-
ville coke region. It extends through West Virginia, inheriting
in that state a slightly increased volume of bituminous matter.
The cokes made from these coals are firmly established as regards
purity and calorific energy in all metallurgical operations.

Section 3. This section, consisting 6f the dryer qualities of
coking coals, is next in magnitude to Section 1 and only secondary
in quality to Section 2. These coals, under careful oven treat-
ment, afford good coke; they contain 20 to 25 per cent, of volatile
combustible matter.

This strip is located in Pennsylvania, Maryland, and the Vir-
ginias. It is situated along the eastern border of the Appalachian
field. Its* coal can be coked in horizontal ovens with fairly good
results; but, with some exceptions, it does not usually inherit the
hardness of body and calorific energy of the cokes from the coals
of Section 2.

It is quite evident that the vertical types of coke ovens are
best adapted for the production of the best quality of coke from
this family of coals, as they confer on it the essential physical
property, hardness of body, which assures its value as a blast-
furnace fuel. They would also afford an increased percentage of
coke from these rather dry coals as compared with the horizontal
type of coke ovens.

394 TREATISE ON COKE

It is also evident that in using the vertical or retort coke oven,
in making coke from these coals, the plant should be provided
with the necessary apparatus for saving the by-products of tar and
ammonia sulphate, as the profits from these will be found helpful
on the credit side of earnings.

As it is now becoming evident that the comparatively limited
areas of the best coking coals are being rapidly exhausted, the
question of securing the best means of manufacturing coke from
the secondary or dry coals is a pressing one, deserving the earnest
attention of the coke manufacturers who may be required to use
this class of coals.

As the regions of the first-class coking coals become more
reduced in area on the one side, with the expansion of the use of
coke on the other, it follows that the increase of coke demanded
by the iron and steel manufacturers must be supplied mainly
from the coals of Section 3. Some investigations and tests have
been made in the use of retort coke ovens in coking these coals,
which so far have afforded assurance of the best results in coke
from these secondary coking coals. The chief element retarding
the introduction of these' vertical coke ovens consists in the large
capital required in establishing a plant of these ovens, with or
without by-product-saving auxiliary. There would also be an
added expense in mining the coal in the thin beds of this section,
with the added cost of disintegrating and washing the coal pre-
paratory to charging it into the ovens. Some compensation is
afforded in this locality in the reduced railroad freight eastwards.

Section 4. The coals embraced in this section are very dry,
holding only 15 to 20 per cent, of volatile combustible matter, and
requiring special oven treatment. It is situated mainly along the
eastern border of the Appalachian field, from Northern Pennsylvania
to Southern Virginia. It has several outlying and detached fields,
such as the Blossburg, Ly coming, Broad Top, Cumberland, etc.

There are some notable additions to the outer edge dry coals.
One of these is found at Johnstown, Pennsylvania, where the coals
contain only 16 to 19 per cent, of volatile matter, and although
located in the third section of medium coking coals they really
belong to the fourth section of dry coals. From its geographical
position westwards, its coal should inherit at least 25 per cent, of
volatile matter, but it is a remarkable fact that a broad belt of
this exceptional dry coal is found in this inner section of the Appa-
lachian field. Its extremities northeast and southwest have not
been defined.

For the proper treatment of this section of extremely dry coals
the narrow vertical oven must be used. The coal will also, in
most instances, require preparation by disintegration, in separating
slates and pyrites, and in many cases by washing.

In this connection, a very marked example of the effects of
coking Blossburg coal in beehive and Semet-Solvay ovens has

TREATISE ON COKE 395

come to notice. In the round oven this dry coal affords 61 per
cent of marketable coke. In the Semet-Solvay oven it yields
78 per cent, of large coke. Samples of each were tested in the
laboratory for resistance to hot carbon dioxide. A few grains of
each were placed in a test tube, and submitted to the action of
a stream of hot carbonic-acid gas, for equal periods of time, with
the following results:

LEFT AFTER TREAT- Loss AS
MENT WITH CO2 CO

Semet-Solvay 88 . 8 11.2

Blossburg 65.4 34 . 6

These tests indicate the very wide difference in the hardness
of the body of the coke and its property of resisting the dissolving
agency of carbon dioxide, such as would be encountered in a blast
furnace. The CO column shows more than three times the prob-
able loss in the horizontal-oven coke above the Semet-Solvay
oven coke.

The difference in product in these ovens is quite large, the
vertical oven affording an increase of seventeen units of coke, or
22 per cent, increase in product over the beehive oven. This
increase contributes to the reduction of the volume of impurities
to the sum total of the coke.

It may therefore be accepted as a general principle in the
treatment of these dry coals that the quick and superior heat in
the retort ovens produces the hardest-bodied coke with an increased
quantity of it.

The Connellsville coke made in beehive and Otto-Hoffman
ovens gave, from a similar test, the following results:

LEFT AFTER TREAT- Loss AS
MENT WITH CO2 CO

Beehive Connellsville coke 91. 0 9.0

Otto-Hoffman 94 . 5 5.5

As a standard for comparison, anthracite, which is a natural
coke, gave the following result:

LEFT AFTER TREAT- Loss AS

MENT WITH CO2 CO

Anthracite 96 . 0 4.0

The Connellsville coke made in beehive ovens, as well as the
portion made in Otto-Hoffman ovens, is best qualified by hardness
of body to resist destructive dissolution in blast-furnace opera-
tions. This assures the economy of fuel per ton of pig iron made,
•and the further advantage of increased output.

In the West, the newer coal deposits afford occasional areas of
good coking coals. The states of Colorado and Wyoming have
shown considerable progress in the production of good qualities
of metallurgical cokes. The gradual debituminization of the coals
eastwards has been noticed very fully in Chapter I.

396 TREATISE ON COKE

An examination of the geological map will show the general
contour of the eastern edge of the great Appalachian coal field.
It will be noted that this eastern contour line maintains a certain
parallelism with the old-time Atlantic shore line of this portion
of the North American Continent. The intense dynamic thrust
westwards in the states of Kentucky, Tennessee, and Alabama,
with the subsequent erosion along their eastern border, has removed
the region of the dry coals, and conferred on their remaining coals
a medium quality between the bituminous coals of the west and
the dry coals on the eastern borders.

With these well-defined areas of coals that can be coked, the
coke manufacturer can decide three important conditions in
selecting a location for his plant: (1) In which of these sections
will he establish his coking plant? (2) What type of coke oven
will be best adapted to producing the best possible metallurgical
coke? (3) Will it be profitable in making coke to save the
by-products: the tar, and ammonia sulphate?

It may be helpful in determining the location of the coke
plant, with the type of oven to be used, to submit the following
considerations :

If possible, the manufacturer of coke should locate his plant in
the best coking-coal belt. This assures the best product of coke,
and removes any suspicions as to its quality; to be liable to be
called on to defend the character of coke made in localities not
well known, or not having the quality of its coke assured, adds
considerable worry to the duties of the manufacturer.

It will be found, on careful consideration, that the difference
in the price per acre is not a vital element of discouragement in
shaping a decision. For instance, the best coking coal land costs
now $600 to $1,000 per acre. An acre of this coal bed, 7^ feet
thick, will afford an output, with careful mining, of 12,000 net
tons of coal. The mining of this coal, under existing conditions
in the Connellsville field, costs about 25 cents per net ton. The
coal requires no disintegration or washing.

PER NET TON

The royalty on coal, at $1,000 per acre, is $ .0833

Mining coal . 3000

Total $ . 3833

Second-class coking coal can be purchased for $50 per acre
for the coal bed alone. Assuming the thickness to be the same,
7| feet, affording 12,000 net tons of coal per acre, the cost will
be as follows:

PER NET TON

Royalty on coal $ . 0041 6

Mining 50000

Total.. $ .50416

TREATISE ON COKE 397

The difference is $0.121 per net ton or $1,452 per acre in favor
of the first quality. But the difference in cost is $950, against
the best coal, having still in its favor $502 per acre, to cover
interest on the increased investment.

Again, supposing that the second quality of coking coal requires
disintegrating and washing, this will add 5 to 8 cents per ton
usually, or at least $600 per acre, making the ultimate difference,
in this case, equal to $1,102 in favor of best quality of coking
coal. It is therefore evident that the best qualities of coking
coals, commanding the higher price, are, under full consideration,
the cheapest in the end.

In the thin beds of the third section of coals the difference in
ultimate cost would be still greater, as the increased cost of mining
and mine ways would have to be considered.

COMPARISON OF DIFFERENT TYPES OF OVENS

In the selection of coke ovens for coking the several qualities
of coals, the table on page 398, which gives, approximately,
the cost and output of each type of oven, will be found helpful.
This table is believed to be approximately correct, but with the
varying cost of materials and labor, as well as local'conditions, no
fixed estimate of the cost of plants of coke ovens should be sub-
mitted. The sure method of learning the cost is by direct appli-
cation to the companies or individuals engaged in the construction
of coke-oven plants.

It may also be submitted, in explanation of this table,
that the comparative standard of annual production, in market-
able coke, has been fixed at 118,800 net tons. This is about
the yearly product of two banks of Otto-Hoffman coke ovens
of 60 ovens each.

Column (a) gives the estimated costs of these coke ovens.
Column (6) shows the cost, per oven, of the exhaust, condensing,
and scrubbing plant. Column (c) gives the total cost per oven,
including, where used, the by-products-saving plant. Column (d)
gives the average daily product of marketable coke from each
type of coke oven. Column (e) gives the number of each kind of
oven to produce 118,800 net tons of coke per year. Column (/)
gives the total cost of each coking plant. Column (g) shows the
amount of labor and materials to maintain the works in good con-
dition, estimated at 5 per cent, on investment. This charge is
designed to afford a fund to make the necessary repairs during
the 20 years' life of the plant. Column (h) distributes this interest
sum over each ton of coke made. Column (i) exhibits the pro-
portion of the cost of sinking the whole plant in 20 years. It is
estimated that, during this period, 2,376,000 net tons of coke
shall have been made. Column (k) gives the cost of labor in

398

TREATISE ON COKE

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TREATISE ON COKE 399

making coke and saving the by-products. Column (/) shows the
tptal cost per net ton of coke made; it embraces the costs in col-
umns (h), (i), and (&). Column (m) gives the percentage of coke
which each type of oven produces. Column (n) gives the value
of the by-products of tar, ammoniacal liquor or sulphate of
ammonia, and gas per ton of coke. This value is considerably
under the usual sums estimated for these products. But it is
submitted that the value of by-products at the works and in a
more or less distant market differs materially. It may also be
noted that these products have, in common with all others, their
variations in market value. Column (o) shows the saving of coal
by increased percentage of product. Column (p) gives the ulti-
mate cost per net ton of coke produced.

In all the calculations it has been assumed that the best coking
coals have been used. No charges have been made for the prepa-
ration of coals that require crushing and washing. No patent-
right charges have been embraced in these columns. In making
the foregoing comparisons, no credit has been given the retort
ovens for heat supplied for making steam, or for surplus gas for
lighting purposes.

The entire cost of coke made in these ovens can readily be
ascertained by taking the percentage of marketable coke produced
by each type of oven, as given in column (m). For instance, the
beehive oven yields 65 per cent, of coke; it will, therefore, require
Y/ = 1.538 tons of coal to make 1 ton of coke. The cost of the
coal, delivered at the coke ovens, can readily be learned for any
locality. The ultimate cost in column (p) added to the cost of
the amount of coal to make 1 ton of coke will give the absolute
net cost of 1 net ton of coke.

The table on page 400 has been furnished by the United Coke
and Gas Company, of New York City.

In the areas of the best coking coals, the horizontal types of
coke ovens will probably retain their places of usefulness. The
principles involved in the manufacture of metallurgical coke in
these ovens are undoubtedly the true ones, concentrating the
greatest heat at the crown of the oven and graduating it down-
wards toward the bottom of the oven. This secures, under the
moderate pressure of the charge of coal, the liberty or freedom
of the mass to develop cell structure, and secures the deposit of a
maximum quantity of carbon from the gases evolved in coking
as they pass upwards through the incandescent portion of the
charge, glazing it with this deposit of pure carbon.

The manual labor in drawing the round ovens should be
removed, as it is exhausting to the workmen and expensive to
the manufacturer.

In the determination of the quality of coal for the manufacture
of coke, the sure method is to have a sufficient quantity of it
coked carefully in one or more selected types of coke ovens. The

400

TREATISE ON COKE

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TREATISE ON COKE 401

physical properties of the coke, as well as its calorific value for
blast-furnace use, can be accurately ascertained by laboratory tests.

In selecting the type of oven for coking any of the several
qualities of coal, it will be well-directed economy to have this
work performed under the care of an expert in the manufacture
of coke, as not only the type of oven is to be selected as best adapted
for coking the coal, but the proper dimensions of the several parts
of the oven chosen are to be determined.

Attention is invited to the ingenious plant of Doctor Otto for
obtaining the by-products from the beehive type of horizontal
ovens. Doctor Terne, in his paper, calls earnest attention to the
large waste in the United States of this valuable manure in the
manufacture of coke. With the 42,000 of these ovens now in
operation, a large field is invitingly opened to inventors to devise
a practical plan for saving these by-products and augmenting the
oven heat by the returned gas.

The products of Doctor Otto's round oven are shown to be
equal to any of the retort ovens, 75 per cent, coke, 1 per cent,
ammonia sulphate, and 2J to 3 per cent, of tar. The cost of this
oven has not been given. From its plain construction this cost
would be small, as compared with the vertical ovens.

Advisability of Saving By-Products. — An important supple-
mentary consideration for the coke manufacturer is presented in
the question, 'in connection with the use of retort coke ovens,
whether it will be profitable to invest the large additional sum
required in the conduits and condensing plant for the saving of
the by-products of tar and sulphate of ammonia. The approxi-
mate cost of the auxiliary plant for saving these by-products is
given in the table on page 398.

In approaching this inquiry, it may be submitted that hitherto
considerable prejudice has been manifested against the quality of
coke made in retort coke ovens, in which the by-products were
saved. Sufficient evidence has not been developed in this country
to settle this matter by accurate tests in blast-furnace use, but on
the continent of Europe it is alleged that at present no discrimi-
nation is made by metallurgists against this quality of the retort
oven coke, provided that it is made in a careful manner.

There does not appear any evident reason why the exhausting
of the gases in coking should deteriorate, in a marked degree, the
quality of the coke, but it should on the other side, by increasing
its hardness, more than compensate for any loss in the exhaustion
of the gases.

Market for Tar and Ammonium Sulphate. — Mr. Wagner, of
Darmstadt, has recently shown that ammonium sulphate is supe-
rior to Chili saltpeter or guano as a fertilizer in agricultural uses.
In the United States, there are approximately 300 millions of
acres of land under cultivation. Perhaps one-third of these

402 TREATISE ON COKE

retain much of the normal richness and will not at present require
concentrated manures. It is further assumed that one-third will
be manured in the usual way with barnyard and compost manures,
and that 50 millions of acres will be manured by native and
imported guano, phosphates, nitrates, and ammonium sulphate,
leaving 50 millions of acres to be supplied mainly by native
ammonium sulphate. This will require 160 pounds of this salt or
its equivalent to fertilize 1 acre in an ample manner. For the
50 millions of acres, 4 millions of tons of this manure will be
required, but it is not probable that this will be used by the
agriculturists for some time to come.

Reducing the probable quantity of this concentrated manure
that may be required to 2 millions of tons per year, it will readily
appear that the product of ammonium sulphate, during the year
1893, did not greatly exceed 60,000 tons, leaving 1,940,000 tons
to be provided for. Should the coke ovens of the United States
be changed to save this by-product, from the 10 millions of tons
of coke, it would afford 1 million of tons of ammonium sulphate,
leaving a deficit of 940,000 tons. The outlook for a market for
ammonium sulphate is well assured. It may be noted, however,
that in competition with other manures its price will be held at
a maximum not greatly exceeding 3 cents per pound.

The chemical works and tar distilleries at Philadelphia, Buffalo,
Cleveland, and Chicago are prepared to purchase tar and ammoni-
acal liquor. - These companies usually own and furnish iron tank
cars for freighting these liquid products from the coke works to
the chemical plants. Some of the companies are prepared to
receive the tar during all the months of the year; others require
the coke manufacturer to store the tar in great tanks during the
winter months.

It becomes an important consideration, in this connection,
how far the coke manufacturer should advance these distillates
in order to secure the maximum profit from their sale in market.
It is evident that tar, as it is condensed from the gases at the
coke ovens, can be shipped with the most economy in its crude
state, provided that it can be marketed continuously throughout
the year. Boiling it to pitch involves extended chemical opera-
tions, in securing the utmost economy.

A companion investigation relates as to whether the coke
manufacturer will dispose of the ammoniacal liquor, at the strength
usually required, 2°, 2.5°, and 2.8° Twaddell, or advance it to
ammonium sulphate, either as an agricultural manure or for
chemical uses. The latter involves an ammonia-factory addition
to the condensing plant, with expert chemical supervision.

If the market or chemical works is not at a great distance
from the coke works, it would in most cases conduce to economy
to ship the ammoniacal liquor in the moderate strength usually
required by the chemical companies. If the market is quite

TREATISE ON COKE

403

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404 TREATISE ON COKE

distant, it becomes a question of the cost of transportation in ship-
ping the liquor or advancing it to the ammonium sulphate. In
this latter case it is evident that the manufacture of ammonium
sulphate at the coke ovens would be the true economy, as the
freight charges on the ammoniacal liquor would be quite large.

It may be noted in this inquiry that it requires 3,520 gallons
of 2° Twaddell of the liquor to make 1 net ton of the sulphate of
ammonium, composed as follows:

59.410 per cent. 5O3 (sulphuric acid)
25.060 per cent. NH.< (ammonia)

.018 per cent. Fe2O^ (ferric oxide)
15.512 per cent. H.2O (water)

100 . 000

About 8 per cent, of ammonia is lost in the manufacture of
ammonium sulphate.

It may be noted here that the cost of gas liquor will change
with the size of the plant and the quality of the coal used in
making coke. Coals with large volumes of volatile matter will
usually produce the largest amounts of liquor and gas, which can
be sold at reasonable profits, reducing the cost of the coke. The
selling price of the salt, ammonium sulphate, fluctuates from
$50 to $65 per ton in the city markets.

In the larger coke works, producing by-products, this inquiry
broadens in its general aspect, involving two important consider-
ations; first, whether it is more advantageous to supplement the
condensing plant with an ammonia factory and tar-boiling plants,
or second, to invite some established chemical company to erect
at the coke works a chemical plant to receive and treat the crude
by-products, advancing them to tar and ammonium sulphate,
with resultant distillates, thus economizing the freight expenses
in handling these products.

There are some difficulties in establishing an equitable basis
for regulating the prices of the crude products. This standard
might be founded on the market value of the crude materials, or
on their finished products, less the freights in either condition,
to the nearest reliable markets.

On the whole, it would appear that a direct reference of the
value of these by-products in the crude state, in the tanks at the
works, would prove the more practical. The rates to be paid
could be determined by their market values, deducting the freight
thereto at such stated intervals as would be equitable to the
producer and manufacturer.

An experiment has recently been made to utilize benzole in
enriching illuminating gas. So far the results appear to be very
encouraging. Should this new application prove successful, it
would add materially to the revenue of the coke manufacturer,

TREATISE ON COKE 405

from the tar by-product. It has been found that in tar boiling,
about 2 gallons of this distillate can be secured in the making of
1 ton of coke. The benzole is estimated to be worth 13 cents
per gallon.

In some portions of the United States and Canada, briqueting
coal waste and bog materials has been installed in a small way.
Should these industries continue to expand, a large home market
would be secured for the tar products of the retort coke ovens.
Tar is also coming into a liberal use in the manufacture of roofing
materials.

CHAPTER XI

THE FUEL BRIQUETING INDUSTRY

In Europe, during the past quarter of a century, the briquet-
ing industry has been developed until at present it has impressed
its importance among the world's industries. In this manu-
facture, the lower qualities of combustible fuels are utilized,
placing them in compact forms for manufacturing, marine, rail-
road, and domestic uses. The expansion of this industry, with
its increasing value in economizing waste products, has been
brought into notice in the United States mainly through the
agencies of the consular service. The combustible elements used
in this manufacture consist of slack coal or screenings, anthracite
culm or dust, coke breeze, lignite coal, charcoal dust, bog turf,
carboniferous mud, and petroleum. The manufacture consists in
pulverizing these elementary materials and then mixing them
thoroughly with the necessary bonding matter, consisting chiefly
of coal tar or pitch; the composition is then pressed into several
shapes to meet the consumer's needs.

Evidently, this industry is in its most advanced condition in
countries inheriting large areas of inferior qualities of coals, or
with broad localities of peat bogs, and where fuel is high priced.
It has also been largely developed in the countries in which retort
coke ovens are in large use, producing coal tar as one of the chief
by-products, which can be used in its crude state or boiled to
pitch, thus contributing the important bonding material in the
manufacture of briquets. It may be noted, in this connection,
that in most of these countries producing briquets, the price of
good coal, especially for domestic use, is nearly prohibitory, ranging
from $3 to $20 per ton. To insure a market for the briquet prod-
ucts, the price must be considerably under that of good coal in
the several countries in which briqueting has been established.

At this time Germany is the largest producer of briquets, and
with the development of this industry there have been invented
many varieties of briqueting machines. France, Belgium, Austria-
Hungary, Netherlands, Norway, and Great Britain have also
taken up this manufacture with much energy and have made
hopeful progress. These examples of the economy of utilizing
the less valuable fuels in briquets are extending the industry to

406

TREATISE ON COKE 407

other countries, especially to those having large deposits of the
raw materials suitable for the manufacture of briquets. In 1882,
4,000,000 metric tons of briquets were produced; it is now esti-
mated that nearly 25,000,000 tons are produced, or almost 3 per
cent, of the total product of coal and lignite.

Fuel briqueting has for its aim the accomplishment of the
following objects: (1) the utilization of the fine material una-
voidably made in the mining and handling of coal; (2) the crea-
tion of a good hard fuel to burn practically without smoke or
odor; (3) the concentration of the greatest number of heat units
into the smallest space practicable, by cleaning and compressing
material of inferior heating value.

In the mining of coal, a large proportion of the output of a
mine is often necessarily dust, slack, or culm, of which a certain
amount is wasted. In the case of coking coals, the slack is gen-
erally charged into ovens, but anthracite dust is usually wasted.

To appreciate the advantage of using fuels that burn without
smoke or odor, one should contrast some American cities with
those of Germany. The dense trailing clouds of smoke from mill
and factory chimneys, which are so familiar a sight in Pittsburg
and other cities in the United States extensively burning raw
coals rich in bitumen, are said to be rarely seen in those sections
of Germany in which briquets are largely used. In this latter
country, the indiscriminate shoveling of raw bituminous coal into
steam and other furnaces is considered an ignorant and wasteful
proceeding.

The third object — that of obtaining concentrated fuel — is one
not to be overlooked when fuel is to be transported long distances
before it is used, and also when storage room is limited. Many
coals require washing to remove impurities before coking, and a
similar process is sometimes. advantageously employed in briquet-
ing processes to clean the material used.

The characteristics desirable in fuel briquets are enumerated
in the following specifications issued by the French Navy and the
Belgian State Railway: (1) the briquet must be hard, homo-
geneous in density and size, only very slightly hygroscopic, and
should burn almost without smoke or odor; (2) the dust and
breakage caused by handling and transportation should not exceed
5 per cent.; (3) the specific gravity should not be less than 1.19;
(4) the briquet should ignite readily, burn with a cheerful flame,
and retain its shape until completely burned; (5) the ash should
not exceed 9 per cent, and the evaporation results should at least
equal those of the best lump coal, from the screenings and dust
of which the briquet was made.

Briquets are made in various sizes and shapes, some of which
are shown in Fig. 1. The large briquets in the background are
for factory, marine, and locomotive use, and are broken before
being fired, while the others are used whole; the scale gives an

408 TREATISE ON COKE

idea of their dimensions. The Zeitz and the briquets between
them are for factory, and the smaller ones in the foreground for
domestic, use. They are made in sizes ranging from over 20
pounds each to a size that takes several to make a pound. Indus-
trial briquets are usually of a square or oblong form, convenient
to be closely packed or built up into a pile like bricks. They are
generally loaded on cars for transportation, packed closely, and
are similarly stored around works, particularly when intended to
be kept for a time, or when large storage capacity is not available.
In connection with the storage of briquets, it is of importance to
note that there is practically no danger from spontaneous com-
bustion, as is sometimes the case with run-of-mine bituminous
and other coals when stored. Each briquet generally bears the
initials or trade mark of the company by which it is produced,

FIG. 1. BRIQUETS OF DIFFERENT FORMS

so that in case of any defect in quality the inferior briquet can be
readily traced to its source of production. When burned whole,
they usually are consumed slowly and give out a steady, moderate
heat for a long time; when it is desired to quicken or intensify
the flame, they are broken up, and in this condition are especially
adapted to flue or tubular boilers, sugar evaporating, smelting and
annealing furnaces, in glass manufacture, or in porcelain and
cement factories — wherever, in fact, a fuel capable of producing
a long, fierce flame is desirable.

Mr. Robert Schorr states, in a paper on Fuel and Mineral
Briqueting, read before the American Institute of Mining Engi-
neers, that "of the many shapes used, the prismatic shape with
rounded edges is, as a rule, the most popular. Heavy blocks
allow of a large output with a comparatively small investment,
and they are very convenient for storage. However, they have
the disadvantage of large, smooth surfaces, and unless broken up

TREATISE ON COKE 409

prior to being fed into a furnace they are apt to smother the fire
and choke the draft, a circumstance that is nearly always the
case with a poor grade of coal or one that has been too finely ground.
To facilitate the breaking up of the large blocks, channels are
pressed into the bricks, or they are perforated in one operation
while being formed in the press. This construction offers the
advantage of a better air circulation. The manufacture of tubu-
lar, or polygonal, briquets is very limited.

The French Navy estimates 820 kilograms of fuel blocks per
cubic meter of bunker capacity (more than 51 pounds per cubic
foot), i. e., 10 per cent, more as compared with the storage of
lump coal. The losses in dust seldom exceed 4 per cent., while
the best Welsh coal averages about 30 per cent., and in stormy
weather nearly 50 per cent., dust, which reduces the stored heat-
ing capacity very considerably. Railroad transportation, even for
long distances, causes generally not more than 3 per cent, of dust.
Cylindrical, ball, and egg-shaped briquets give still less dust and
breakage, but they are wasteful in space. Their shape insures a
good air circulation and consequently a complete combustion.

The specific gravity of briquets varies with the material and
pressure employed, and is usually as high as that of the fuel from
which they have been made, i. e., from 1.1 to 1.4.

COMPOSITION OF BRIQUETS

Briquets may be made of any of the following materials: coal
slack, screenings, or dust; anthracite screenings or culm; coke
breeze or small coke; lignite coal; charcoal; peat or turf; carbon-
iferous mud; petroleum.

Coal-Slack, Screenings, or Dust Briquets. — Among the princi-
pal carboniferous materials used in the manufacture of briquet
fuels are coal slack, screenings, and dust. Mr. Schorr states that
"the size and cleanness of the fuel are important items. The
grains should not be larger than J inch and not less than -3-2- inch
in size to make a good-burning briquet. If the coal is ground too
fine it will make a very handsome-looking briquet, but it will
not ignite as readily and it takes a strong draft to burn it suc-
cessfully. The ash content should not exceed 6 per cent. If
greater than this amount, the coal should be washed by water
or treated in a pneumatic separator in order to remove the excess
of ash. If presses with solid resistance are used, the raw material
must be of a commercial dry ness, but in open-mold presses a
large amount of moisture may be present."

Slack from coals rich in bitumen will work into briquets with
an addition of 2 or 3 per cent, of pitch, while leaner grades may
require 6 to 8 or even 10 per cent. ; the last proportion is sufficient

410 TREATISE ON COKE

at times, when the cost of pitch is high, to render such coal unprofit-
able for briquet purposes. Briquets made from bituminous slack,
although not smokeless, are more nearly so than ordinary bitu-
minous coal. When burned in locomotives or any well-constructed
boiler or other furnace with a good draft, they create qnly a thin
translucent mist that contains relatively little soot, and is very
different from the inky clouds that roll up from many factory
chimneys where soft coal is shoveled indiscriminately into the
furnaces. The one notable defect ' of such briquets is that the
mineral pitch, which is used as a binder, contains more or less
creosote; this renders dust and fumes from such fuel acrid and
sometimes irritating to the skin when confined in a close, hot
boiler room.

In the manufacture of briquets from coal slack, screenings, or
dust, the material is reduced by a disintegrator to fine particles
when necessary. The binder is then added, and when pitch is
used as a bonding material the mixture is ready for the heater.
The most common way of mixing is the dry method, by which the
pitch is ground up and added to the coal in a dry state. The com-
bined mass of coal and pitch is then placed in a heater in which
the pitch is melted; in some instances, the heater is a drying appa-
ratus as well, removing any water that may be in the coal. After
treatment in this machine the hot mass passes to the presses,
where it is rapidly pressed into the form of briquets.

Anthracite-Screenings, or Culm, Briquets. — Anthracite screen-
ings, or culm, has been used in the manufacture of briquets. In
some cases, a slight mixture of bituminous slack coal is added to
reenforce the bonding pitch. Owing to the cost of the binder and
the comparative cheapness of the coal, anthracite briquets have
never been a commercial success to any great extent. At such
points as Chicago, where anthracite is transferred from boats to
railroad cars, or at seaboard towns where large amounts are
handled and much fine coal made, this fine material is sometimes
briquet ed for lo'cal use.

Coke-Breeze, or Small-Coke, Briquets. — In the manufacture of
coke in beehive coke ovens, about 2 to 3 per cent, of small coke
or breeze is produced. This is reduced to very small sizes or dust
and mixed with pitch or tar in the usual way. Necessarily this
coke breeze must be washed to be freed from the ash or slate asso-
ciated with it, which often amounts to 20 or 30 per cent. The
manufacture of these coke briquets is very trying to the machinery,
as the powder is very sharp, wearing away the metal of the
grinding and mixing machinery very rapidly. In all countries in
which the coke-making industry is large, an inviting opening is
presented for the utilization of this coke waste in the manu-
facture of coke briquets. The briquets made from coke dust are
especially desirable for domestic uses, as they are almost smokeless.

TREATISE ON COKE 411

Lignite Briquets. — Lignite, or brown coal, is a very important
element in the manufacture of briquets. It varies in its value
and adaptability for briqueting purposes according to its geologic
age, hardness, and the percentage of water that it contains. A
lignite with less than 30 per cent, of water is very difficult to work
by the usual processes. The amount of moisture in lignite fuel
forms the key to the whole economic briqueting process. The
crude brown coal is brought from the mine, crushed and pulver-
ized, and then dried and heated with the proper temperature to
develop the latent bitumen in the lignite and make the powdered
mass plastic and easy to mold, under heavy pressure between
heated iron jaws, into a hard, clean briquet, with a glistening
surface and sufficient firmness of structure to stand weather,
transportation, and other contingencies. To do this perfectly
and economically, the natural lignite should contain, as it comes
from the mine, approximately enough moisture so that heating
to the proper temperature for pressing will evaporate out just
sufficient water to leave it at the proper degree of moisture. The
ideal proportion is about 45 per cent, of water. Considerable
interest attaches to lignite as a briqueting proposition in the differ-
ent countries, as it is an inferior fuel direct from the mine, on
account of its tendency to rapidly disintegrate on exposure to
the air.

Charcoal Briquets. — In the countries in which much charcoal
is produced, the dust made in its manufacture and handling
affords a most excellent and pure material for the manufacture
of briquets. The usual mode of preparation is quite economical,
and the binding material is mixed with the charcoal dust in the
usual way. These charcoal briquets afford the purest quality of
fuel and are especially adapted for supplying heat in the manu-
facture of iron and steel.

Peat, or Turf, Briquets. — The bogs in which peat is contained
cover extensive areas in the northern temperate latitudes, both
in Europe and America. In Germany, they cover nearly 11,583
square miles, and in Ireland, according to Snell, they cover the
tenth part of the country. The depth is very variable, but is, on
an average, 5.4 to 7.6 yards; in Ireland, bogs are found with a
depth as great as 16.3 yards. It may be estimated that 1 square
mile (2.59 square kilometers) 5.4 yards deep will give about
1,813,000 metric tons of dried peat; hence, it will be seen that the
amount of fuel in those bogs is enormous. Peat is organic matter
formed from mosses and other minor plants that have been sub-
merged in water and are thus preserved in the bogs.

As a material for fuel, peat ranks "next in the natural order
below lignite, in that it is of similar, but much more recent, geo-
logical order, contains more water, is but slightly carbonized, and
has a correspondingly lower thermal value than lignite, or browrn

412 TREATISE ON COKE

coal. The task of converting peat into serviceable fuel consists
of cleaning the material of roots and rubbish, reducing the water
to a smaller percentage, and condensing the peat in volume so
that its thermal value shall be raised to practical efficiency. This
is done by various methods, which may be grouped under three
heads, according to the form that the ultimate product is to
assume: first, compressed peat, with or without the admixture
of coal dust or of inflammable matter; second, peat coke; and
third, briquets made by compression, with or without heat, of the
material prepared by the first process.

Peat cut from the bog has been used for centuries and in the
ordinary process of drying the material is cut into cubes and laid
in the air, where most of the water held between the fibers soon
leaches out by gravity or evaporation. Machine peat, which is
the compacter and better article, has come into use within recent
times. Two principal systems are distinguished in making machine
peat, depending on the treatment of the raw material immediately
upon raising it from the bog. One plan is to digest the peat with
the addition of water into a liquid mud, which is then poured into
molds in the open air and, after losing some of its water, divided
into blocks and allowed to dry. The other and more commonly
employed process consists of grinding or mincing the peat as it
comes from the bog into a soft, plastic mass, which is then made
into bricks and dried. This grinding of the peat is to better pre-
pare the fibers to give up their liquid contents.

One of the important improvements of recent years has been
attained by mixing the peat pulp as it passes through the grind-
ing machine, with other inflammable materials; such as, bitu-
minous coal dust, or slack, up to 30 per cent. ; anthracite culm,
to 40 per cent. ; or dry sawdust, to 15 per cent. These dry pulver-
ized materials, when mingled with the wet peat, not only greatly
enhance its subsequent value as fuel, but facilitate the drying
process and render it tough, dense, elastic, and capable of being
pressed cold into briquets of high quality. But by far the most
modern, scientific, and rational method of utilizing peat appears
to be that of converting it into coke by carbonization in retort
ovens, with recovery of the gas, tar, and other by-products of distil-
lation. One method of coking peat consists in carbonizing the peat
in closed ovens heated by burning the gases generated by the coking
process itself. Another method makes use of the electric current
to carbonize the peat. Comparatively recently, several processes
by which artificial coal or briquets have been made successfully
from peat by the application of machinery have been patented,
but have not yet been fully established on an industrial basis.

Carboniferous-Mud Briquets. — Carboniferous mud is a lower
vegetable deposit than peat or turf. In some instances, it is
derived from the refuse of the turf industry; at other localities,

TREATISE ON COKE 413

along the estuaries of lakes and rivers, these black-mud accumu-
lations are found. They are composed mainly of vegetable matter,
rotted principally under water and mixed with various percent-
ages of earthy matters. The black mud requires very little prep-
aration for its manufacture into briquets; the most important
consists in drying the briquets after leaving the press. The
manufacture of fuel on a large scale from the black mud of grass
meadows is an important industry in several countries of Europe,
notably in Holland and Russia; mud briquets are also reported as
being made on a commercial scale in the United States.

Petroleum Briquets. — Petroleum briquets have been manufac-
tured in various ways in different countries, notably in Russia,
France, and the United States, as a fuel for steamships and cer-
tain industries where rapid production of heat is desirable. The
advantages of such a substitute for coal are readily apparent —
less storage room, complete combustion, etc. It is somewhat
surprising that petroleum has not been more generally utilized
in this form. The objections were that the briquets were said to
injure the boilers after a short time, by reason of some chemical
action produced in combustion; further, the blocks did not keep
their form under the action of the heat, but fell through the fire-
box in a liquid state ; and the price is stated to be two-thirds more
than that of coal. A company is said to have been formed for
the manufacture of petroleum briquets, which claims to have
obviated all the objections except that in regard to price. Petro-
leum briquets can be used for any kind of domestic or industrial
work without changing the furnaces.

Binders. — Bonding material is used to cement the small par-
ticles of fuel employed in making briquets except such as contain
the necessary bituminous matter, such as lignite, peat, carbon-
iferous mud, and petroleum. The greater the amount of bitu-
minous matter, the smaller is the quantity of binder employed.
The most common binder used is pitch in its various forms, the
pitch being a by-product in gas and coke making, and to a limited
extent from furnace gases in ironworks that use raw coal as a
fuel. Hard pitch is of foremost importance in this connection,
and when of a good quality should contain 75 to 80 per cent, of
carbon and only .25 to .5 per cent, of ash. The addition of from
5 to 10 per cent, of pitch as a binder improves the heating value
of fuel from 2 to 4 per cent., depending on the number of heat
units possessed by the raw material. Tar and soft -pitch binders
have many disadvantages that do not apply, to the same extent,
to hard pitch. The presence of the light and heavy volatile
hydrocarbons in the former creates smoke and smell when this
binder is used in briquets; also, the point of distillation of soft
pitch is about 400° F., while that of hard pitch approximates

414 TREATISE ON COKE

800° F. Thus briquets made with soft pitch have to be kept cool
or they will soften and, by sticking together, form large lumps.
It has been stated that the briqueting of slack and fine coal in
Germany is practically limited by the amount of pitch obtainable
from the by-product coke ovens.

Among the other organic binders, the most important are
starch paste and sugar molasses; but these, and a few others of
this class, have not as yet attained more than local importance.

The use of inorganic binders is to be avoided wherever organic
binders may be had at reasonable cost. The most important
inorganic binder is magnesia cement, which is both cheap and
abundant. The use of 5 per cent, of this material is said to pro-
duce a stronger briquet than that made by any other binder;
when 5 per cent, of this binder is used, the quantity of ash added
amounts to but 2.5 per cent. Mr. Schorr says "the process of

FIG. 2. OPEN-MOLD PRESS

using magnesia cement is very cheap, as no drying is required and
the only fuel expended is that for power. The briquets harden
gradually at the ordinary temperature, and after from 6 to 10
hours are strong enough to be stored or handled ; in a few days
they are capable of standing a pressure of from 7,000 to 22,000
pounds per square inch. Wherever good hard-pitch briquets are
in the market, it will be difficult for a magnesia-cement briquet to
compete with it on account of the higher ash content of the latter.
One hears and reads from time to time of a new matrix or
binder that will cheapen the cost of coal briquets, facilitate their
manufacture, and improve their quality; but these accounts usually
are founded rather on the claims of inventors and promoters than
on demonstrated industrial results.

Presses. — To obtain a solid briquet, it should be of uniform
density, which can only be effected by using a high pressure and
by keeping a proper ratio of the cross-sectional area of the briquet

TREATISE ON COKE 415

to its height. If the pressing is done against a solid resistance,
and from one side only, a comparatively higher pressure must
be exerted, and even then the density in various layers will
differ. The larger the briquet, the higher should be the pres-
sure per square inch. The depth of the briquet has an impor-
tant bearing on the character of the briquet produced; even
the largest and heaviest fuel blocks should not exceed 5 inches
in depth.

There are two general types of presses in use : the press with
open mold and the press with closed mold. The open-mold press,
Fig. 2, is extensively used for lignite and peat; it works well with
washed coals containing up to 20 per cent, of water and gives a

FIG. 3. CLOSED-MOLD PRESS

big production. Its construction is simple and solid, and it is
easy to work. It has for its elements a pipe or tube whose cross-
section is, in shape and size, that of the face of the briquet, and
a piston that fits one end of the pipe or mold, the other end being
open. When a sufficient amount of "paste," or briqueting mate-
rial, falls into the mold, the piston moves forward and forms a
briquet; when the piston recedes, new material drops from a hopper
into the space between the piston and the previous briquet pressed;
then the piston moves forward again, pressing a new briquet and
at the same time forcing a finished briquet from the open end of
the mold, thus forming a continuously moving column. The pres-
sure exerted by the piston in this type of press need not be -very
great, being dependent on the friction of the completed briquets

416

TREATISE ON COKE

against the walls of the mold and the length of the mold. To
increase the pressure, the mold is sometimes tapered from the
piston to the open end. Notwithstanding the difficulty of secur-
ing a desirable pressure in this type of mold, it is the one most
in use, having the counterbalancing advantage of rapid pro-
duction of briquets, which the closed-mold method lacks. It is
very wasteful in the consumption of power. Open-mold machines
are generally fitted up in pairs on the Bourriez continual-motion
system.

The closed-mold, or solid-resistance, presses, Figs. 3 and 4, are
divided into two classes; tangential presses and plunger presses.
The tangential type comprises a mechanism that consists of
wheels working against each other, and carrying molds, or molds

FIG. 4. PLAN OF CLOSED-MOLD PRESS

and corresponding teeth, on their peripheries. The action of this
press is continuous and permits a large number of small briquets
to be made in a short time. However, the briquets are apt to be
poorly and unevenly pressed, and the waste of material and the
wear upon the machine is very high, while from-9 to 10 per cent,
of binder is required. This press makes the familiar egg-shaped
briquets suitable for domestic use, but generally too expensive for
industrial purposes.

The more important class of the closed-mold type is the plunger
press. In this machine, molds filled with the paste, or briquet-
ing material, by a distributor, pass under an arrangement that
exerts pressure on one or both sides of the briquet, which is after-
wards ejected automatically. A large number of these presses are
in operation making briquets of all sizes.

TREATISE ON COKE 417

METHODS AND COSTS OF MANUFACTURING BRIQUETS

Having considered the general character and the various kinds
of briquets, we will now take up the methods and costs of manu-
facturing briquets in the principal countries manufacturing this
form of fuel. Much of the information relative to the briquet
industry on the continent of Europe and in England is taken
from the reports of the United States Consuls stationed in these
countries.

Briqueting in Austria-Hungary. — While the manufacture of the
briqueted fuel in Austria-Hungary is of comparatively recent
origin, it has had so rapid a growth that it bids fair soon to be
classed among the important industries of the country. Its
remarkable development is attributed to two causes, viz., the
comparatively high price of fuel in some parts of the monarchy
and the great abundance of waste or inferior coal in others.

Until quite recently, briquets have constituted only a com-
paratively insignificant item in the household economy of the
inhabitants of Vienna. During 1902, however, various enter-
prising firms, chiefly German, took energetic steps to popularize
the article, and their efforts have, to a certain extent, been suc-
cessful. Trieste has one briquet factory that turns out about
5,000 tons of fuel annually.

The principal ingredient of the briqueted fuels manufactured
in Austria-Hungary is coal dust or screenings. In Bohemia, coal
is mined in large quantities, and briquets are chiefly made of the
refuse of the coal. In the greater portion of Hungary, bituminous
coal is employed in the manufacturing plants, while in Styria
and Bosnia, lignite is utilized. In Croatia-Slavonia, as well as in
Carinthia and some other parts where large quantities of charcoal
are produced, charcoal dust has of late also been used in the manu-
facture of "patent fuel."

The cost of manufacturing varies greatly, according to the loca-
tion of the plant and the kind of material used. Bituminous
screenings are, of course, cheaper than anthracite, and the price of
crude labor varies in the different portions of the monarchy from
30 cents to $1 and even more a day. The briquets made in Trieste
are of the charcoal variety and are produced at a cost of about
$10 per ton. The cost of manufacture of lignite briquets in the
province of Styria is said not to exceed $4 per ton. The selling
price of lignite and bituminous briquets ranges from $4.50 to
$6.50 per ton, while the charcoal briquets manufactured at Trieste
sell at $12 per ton. The prices of other fuel for domestic use are
as follows: beech wood, $2 per cubic meter, or about $7 per cord;
bituminous coal, from $3 to $6 per ton, according to quality; gas
coke, $10 per ton; charcoal, $12 per ton. Nearly all the methods
of manufacture are of German origin, and Germany still supplies
many of the machines used.

418 TREATISE ON COKE

The charcoal briquets manufactured in Trieste are made in
the following manner: The charcoal screenings are first ground
fine, after which coal tar is added, and the mixture stirred until
it has the proper consistency for pressing. The latter is then
molded into egg-shaped pieces weighing, in a dry condition, from
2 to 3 ounces. These pieces are dried in kilns and in the open air.

Substantially the same process is employed in the manufac-
ture of lignite and bituminous briquets. Lignite, however, owing
to its low heating power, is seldom used without the addition of
from 20 to 30 per cent, of anthracite or bituminous coal. This
mixture of coal is likewise ground fine, and about 10 per cent, of

FIG. 5. THE WEISNER BRIQUET MACHINE

pitch added. The composition, after having been thoroughly
blended and partially dried in a kiln having a temperature of
from 158° to 176° F., is pressed into bricks weighing about 10
pounds each. The product is then ready for the market.

Formerly, pitch was universally used as a bonding material,
but its present high price has led many manufacturers to substi-
tute for it a composition of milk of lime, tar, and "Weisner's
patent bonding material" (a solution of sulphuret of lime with free
sulphurous acid, resinous substances, and lignite).

The average daily capacity of the Trieste plant, which employs
from twenty to thirty men, is from 20 to 30 tons.

Edward Weisner and brother, of Vienna, manufacture a hand-
power machine, Fig. 5. It works as follows: The funnel or
hopper a is filled with the composition to be pressed into briquets.

TREATISE ON COKE

419

A turn of the flywheel causes the plunger b to rise. The sliding
apparatus c, which in the meantime has been filled from the hop-
per, then passes over the mold and pours its contents into it.
Another turn of the wheel brings the sliding apparatus back under
the funnel to be again filled. In the meantime the plunger enters
into the mold and sufficiently compresses the contents to form
the briquet. The plunger and the bottom of the mold then rise
simultaneously until the latter is in line with the base of the
sliding apparatus and the pallet placed on the discharging table d.
While the plunger continues to rise, the sliding apparatus, filled
with material, moves over the mold, thereby pushing the finished
briquet on the pallet and at the same time discharging its contents
into the mold, whose moving bottom has in the meantime again
dropped down.

The heating value of the various kinds of coal briquets manu-
factured in Austria is stated to be as given in the following table:

Kind

Calories

Anthracite
Bituminous
Lignite
Charcoal

5,000 to 6,000
3,500 to 4,000
3,000
7,000 to 8,000

Briqueting in Belgium.— The latest available official statistics
concerning briqueted fuel in Belgium cover the year 1901. They
show that there were at that time thirty plants engaged in the
manufacture of various kinds of briquets, - distributed as follows:
Twenty-seven plants in the province of Hainaut, with a total of
sixty presses and employing 1,237 workmen, and three plants in
the province of Namur, with ten presses and employing 83
workmen.

The amount of coal consumed in the province of Hainaut was
1,130,460 tons, from which was produced 1,236,450 tons of briquets,
valued at $4,608,068, or $3.726 (19.31 francs per ton). The fol-
lowing tabulated statement shows the annual production and the
average price per ton of briquets in the province of Hainaut dur-
ing the last 5 years.

Year

Production
Tons

Average Price
Per Ton

1897

1,030,330

$2.413

1898

1,119,180

2.586

1899

1,023,290

3.128

1900

1,091,150

4.599

1901

1,236,450

3.726

420

TREATISE ON COKE

The three plants in the province of Namur make coal and pitch
briquets, and during the year 1901 consumed 94,790 tons of coal
in the production of 105,870 tons of briquets, valued at $383,915.25
or $3.626 per ton.

Materials from which briquets are made in Belgium vary accord-
ing to the use for which the fuel is destined. When manufactured

(fe) PLAN
FIG. 6. MACHINE FOR SORTING, WASHING, AND MAKING BRIQUETED FUEL

a, separating drum; b, endless-chain bucket; c, oscillating table: d, coal-washing tubs;
e, tank (or absorbing well); /. bucket chains; g, drain pipes; h, forcing screw; i, bucket chain;
/, recipient; k, proportional distributor of pitch and coal; /, bucket chain; m, Carr grinder;
n, bucket .chain; o, pug mill and distributor; p, r, distributors; q, s, briquet presses;
/, cutting table; «, steam heater; v, steam engine; w, ventilator; x, beams and columns;
y, general transmission.

for railroad consumption, generators, power plants, etc., about
90 per cent, of bituminous coal is used, to which is added mineral
pitch or coal tar. The mixture varies according to the nature af
the coal employed, whether ruddy, close, or half free-burning

TREATISE ON COKE 421

coal. The paste contains from 13 to 14 per cent, of water. When
intended for domestic use, about 30 per cent, of clay or marl is
added. Briquets of an inferior quality are made from a mixture
of sawdust, tannery and brewery residue, peat, turf, and lignite.

A plant for separating, washing, and making coal briquets is
illustrated in Fig. 6. This plant can work up 500 tons of coal into
briquets in 10 hours, and costs 8,000 francs ($1,544). The work
is divided as follows: (1) to sort 300 tons of coal; (2) to wash
150 tons; (3) to make 120 to 150 tons of briquets weighing 11
pounds each, and 50 tons of ovoid balls weighing 5.289 ounces each.

The coal first passes through the separating drum a, which
separates it into three classes, 70-40 millimeters, 40-25 milli-
meters, and 25-0 millimeters. The 70-40 and 40-25 sizes are put
aside for sale. The 25-0 size is passed into the tank by means
of the endless-chain buckets 6, from which it passes into the shaking
screen c, which separates it again into three classes. The first
two classes are carried to the washing tank d\ after washing, they
are carried to tank e, by the endless-chain buckets /, which then
hoists them to the draining tower g. The third class is also ele-
vated by a movable bucket to a storing tower. A screen conveyer h,
working at the foot of the towers, removes the washed coal, when
sufficiently drained, from either tower and permits the reclassing
of the three kinds of coal. It is evident that the arrangement
permits the manufacture, according to the requirements of the
purchaser, of three sorts, unwashed, mixed, or thoroughly washed.
The coal is then carried into the tank of the endless-chain buckets i
that hoist it into the tank. Under this tank is the proportional
distributor of pitch and coal k in which the exact division of pitch
and coal is made. The mixture is then carried to the Carr pug
mill m by an endless-chain bucket /. The Carr pug mill is con-
sidered to be a perfect mixing machine and at the same time an
excellent grinding machine. An endless-chain bucket n then
hoists the material to the mixing machine o, where it is trans-
formed, by the action ot steam, into a cohesive paste, which runs
through two openings placed on the right and left side of the -pug
mill. Two screw conveyers specially disposed for cooling the
paste- take it to distributor p of the press q on one side and to
distributor r of the briquet press 5 on the other. The briquets,
as they issue from the molds, are taken to the cutting table / by
means of two irons and separated by hand and then are stored
or delivered.

The average capacity, per day, of plants depends entirely on
the number of machines in use. In some plants, not more than
6,500 briquets are made per day of 10 hours; while in more elab-
orately equipped establishments, 30,000 briquets are turned out
in the same number of hours.

The following table shows hands required and wages paid per
day to work an ordinary briquet machine:

422

TREATISE ON COKE

For Labor, Materials, Etc.

Cost

One foreman operating machine
One stoker
One overseer
Two mixers, each 3.50 francs

$ .965
.868
.772
1 . 351

Two carriers, each 3.50 francs

1.351

Three boys for loading briquets on wagons or cars, each 2 francs. .
One boy for washing and crushing resin

1.158
386

Total

6 851

Oils, packings, etc
Fuel 900 kilos at 20 francs per ton

1.061
3 . 474

Total

4 535

Washed coal dust 25 3 tons at 8 12 francs

39 647

Pitch resin (7 per cent ) 1 957 kilos at 75 75 francs .

28 596

Tar (25 per cent.), 699 kilos at 60 francs
Total

8.096
76 339

Grand total

87.725

Plants are usually equipped as -follows: steam generators;
one motor machine; one coal crusher (in some cases useless) or
drier; one resin crusher or boiler for melting resin; resin and coal
measure for measuring mixture; heating and mixing machine;
mixing machine; occasionally an endless cloth for cooling, trans-
porting, and loading the briquets.

The estimated cost of manufacture, including raw material,
labor, and interest on money invested, is about $3.281 (17 francs)
per ton, divided as follows: coal, $1.64; tar, pitch, or resin, $1.25;
labor and interest on money invested in plant, $.386. The average
selling price for good quality, briquets varies, according to con-
ditions of contract and destination, from $3.474 (18 francs) to
$3.86 (20 francs) per ton.

Briqueting in France. — Fuel briquets have been used in France
for the past 50 years, and the briquet has acquired an importance
in French markets from which it is unlikely to be dislodged so
long as coal retains its supremacy as a generator of steam. The
product of the French mines is friable and inferior to the high-
grade British and American fuels, and until the briquet was per-
fected, a large percentage of the output of the mines represented
a total loss. The manufactured fuel permits what was once largely
refuse to be sold at prices running fairly even with the prices of
the choicest coal taken out of the domestic mines. The French
government requires the railways of the country to maintain a
stock equal to their requirements for 3 months, and this reserve
usually consists of briquets. On railroad locomotives and in

TREATISE ON COKE 423

marine service, briquets are preferred to coal, as their heat is
more reliable, which enables closer calculations to be made as to
the amount of steam that can be obtained from a given weight
of fuel.

While the briquet is destined to continue an important factor
in the French coal trade, the cost of manufacture is so great that
of recent years every endeavor has been made by the railway
companies and the manufacturers of boilers to devise some method
of burning the low-grade fuel direct, and with a considerable
degree of success. The Belgian railway companies were the first
to adopt a definite scheme and, as far back as 1395, began to
make use of coal dust, which did not cost over $1.15 (6 francs) per
ton. In France, The Company of the East first took up the mat-
ter and is now burning washed small coal which is very pure, but
which, nevertheless, may be bought at a far lower price than
run-of-mine coal or briqueted fuel. The Paris, Lyons, and Medi-
terranean Railway Company, which has for years burned briqueted
fuel exclusively, and owns three large factories for the treatment
of the small coal mined along its system, has followed suit with
considerable success. In the burning of fine coal direct, the
fireman is obliged to exercise much greater care, and the
grate bars must be closer together. Without changing the fire-
box and by using a combination fuel, the Paris, Lyons, and
Mediterranean Company has succeeded in securing the same
power per hour and per square yard of grate surface as was
formerly obtained with high-grade fuel alone. In accomplishing
this result, both of the French companies employ coal of rich
quality that tends to conglomerate in the fire. These methods
have been adopted by the Paris, Lyons, and Mediterranean
Railway for the movement of freight, but not yet for the
movement of fast passenger trains.

For general industrial purposes, two systems of burning
extremely fine coal are now recognized as practicable. One of
these involves the feeding of the coal from a hopper upon a moving
grate. The second system requires the construction within the
furnace, of a series of narrow shelves on which the coal rests, the
grate bars being erected vertically. These great economies are
not possible upon shipboard, and, granting their complete success;
still leave the briquet supreme as a means of making the French
fine coal available for navigation and for general domestic pur-
poses. Being dearer than coal, briquets are, according to one
authority, seldom used in manufacturing establishments. The
amount of briqueted fuel consumed in France in 1902 was prob-
ably over 2,000,000 tons, and its use is increasing.

The principal binder used is pitch. The price of this pitch,
most of which is imported from Great Britain, rises and falls in
sympathy with that of coal. The highest quoted price since 1873
was $11.58 per ton in 1900, and it was as low as $1.79 in 1888.

424 TREATISE ON COKE

All qualities of coal are susceptible of being conglomerated;
but in France, the half-bituminous quality of fuel, of from 13 to
17 per cent, volatile matter, is particularly employed. The fine
coal of this grade coheres with difficulty when employed directly
and becomes much more valuable when manufactured. Certain
coals in the Franco-Belgian basin, containing not more than 12
to 14 per cent, of volatile matter, also make good briquets if
employed with from 9 to 10 per cent, of dry pitch. When the
quality of the coal is so low as to contain not more than 10 per
cent, of volatile matter, the resulting briquets burn slowly and
with difficulty. The lignites are slow to conglomerate alone, but
mixed with other combustibles yield a good product. At the
factory near Marseilles, the half -rich anthracite of the Depart-
ment of Gard, and Fuvean lignite are used.

While briquets are sold in a very large number of forms, the
three notable types are: (1) the large square or cylindrical
briquet, weighing about 20 pounds each; (2) the perforated
rectangular briquet, weighing about 1J pounds, and sold for gen-
eral domestic and industrial purposes; (3) the round or egg-
shaped briquet for domestic purposes. The standard recognized
for these briquets by the French Admiralty is the Anzin briquet,
a briquet yielding from 8,200 to 8,500 calories. The manufac-
tured fuel for the navy is required to reach this standard, and
the railway service is scarcely less exacting. The briquet for
ordinary purposes, being in the majority of cases manufactured
from coal of the poorest and smallest grade, averages not more
than 6,600 calories. These commercial briquets are in large part
manufactured from lignite (which is used with difficulty alone)
in combination with forge coal and a relatively high percentage
of pitch. Because of these requirements, it is almost invariably
necessary to wash the small coal, at considerable expense, before
the manufacture of briquets begins.

The manufacture of briquets in France includes coal-crushing,
washing, and drying processes, the first two processes of which
are entirely familiar. Generally the coal delivered to the pressing
machines is damp ; and when the moisture exceeds 4 to 5 per
cent, it is necessary to remove the excess. The presses that apply
a pressure lasting relatively for a considerable time, such as the
kivollier, Evrard, and Bourriez, relieve the paste of the excess
water and give good results even though the paste as it enters
contains as much as 10 per cent, of water. The Rivollier, how-
ever, is the only machine that absolutely guarantees this result.
The presses operating instantaneously, like the Bietrix, which is
manufactured by the house of Couffinhal et Ses Fils, at St. Etienne
(Loire), France, give excellent results, but the product requires
careful drying. It is recognized as necessary and useful to leave
1^ to 3 per cent, of water in the paste when ready for the press.
This quantity contributes to the plasticity of the mass during the

TREATISE ON COKE

425

application of the pressure. In no event does the density of the
briquet equal that of solid coal. There remain always certain
spaces between the component particles, and if the paste is too dry
these spaces contain compressed air, which diminishes 'the solidity
of the mass.

In some cases, it is necessary to eliminate nearly all the water
possible from the coal before the material passes to the presses;
consequently, a drying operation is required, such as is carried on

FIG. 7. OVEN WITH REVOLVING TABLE

in the oven shown in Fig. 7. This oven is circular in shape, com-
posed of a revolving platform of cast iron, and works continuously
with the agglomerating machine. The platform is surrounded by
masonry covered with sheet iron, on which rests a dome with a
passage in the center for a cylinder of cast iron with a shaft fur-
nished with flukes. A lateral firebox produces the temperature
necessary to the heating of the coal and the elimination of any
excess of water. The flames, after passing over the upper surface
of the coal, heat the dome, pass under the revolving table, and

426

TREATISE ON COKE

427

escape at the opposite end by a chimney. Around the covering
of the oven are arranged six openings. The first four are used
to introduce arms provided with spikes that turn the material,
presenting all its parts to the heat of the flame. Opposite the
fifth aperture are two bars that gradually bring the material from
the center to the circumference. These bars also regulate the

FIG. 9. BIETRIX BRIQUET PRESS

thickness of the layer of coal. By means of scrapers, the coal
that is sufficiently dried is removed from the table, through the
sixth opening, to a conveyer that carries it to the press, where it
is made into briquets. Fig. 8 shows the method of operating
such a drying oven in connection with a press.

The pitch for the binder should be crushed as fine as possible
and preferably should be melted before being mixed with the

428

TREATISE ON COKE

coal and brought to the temperature chosen for the fusion. It is
melted in huge basins with bottoms slightly inclined toward the

point of discharge, the load
usually being 7 tons. Fre-
quently the pulverized pitch is
mixed dry with the coal, and
the mixture is then brought
to the proper temperature.

The mixing mill consists
of a vertical cylinder within
which the shaft operates
swiftly moving paddles upon
the churn principle, by which
the incoming pitch and coal
are beaten and mixed as they
move downwards toward the
point of discharge. This cyl-

inder is heated by steam, and
requires as much as 110
pounds of steam per ton.

In 1903, the British presses
were extensively used, though
the Bietrix machine proba-
bly stands equally high. This
latter machine presses the
briquet simultaneously on its
two faces upon the principle
of a nut cracker, the various
models producing 18, 50, 90,
and 150 tons in 12 hours.
The weight of the briquets
is usually 13.2 pounds, but
may be increased to 25 pounds.
Its successful operation re-
quires a paste containing 1| to
3 per cent, of water and 6 to
9 per cent, of pitch, and the
pressure varies from 1,300 to
2,300 pounds per square inch.
The Bietrix press is shown
in perspective in Fig. 9, in
plan in Fig. 10 (a), and eleva-
tion in Fig. 10 (b).

The double compression
is effected by pistons a and 6,
Fig. 10, attached to upper

beam c and lower beam d, respectively, working in molds on
the revolvable disk e The beams c receive their motion through

TREATISE ON COKE 429

rods connecting them with cranks /. The operation of forming
the briquet is as follows: The material in the mold is pressed
down by the descending upper piston a until the upper layer
of the briquet produces so strong friction on the walls of the mold
that it will not yield any longer; at this stage the pivot g of the
beam c shifts, the lower beam d is brought into action, and pis-
ton h then compresses the lower part of the briquet in such a
way that the pressure on both parts is equal. The hydraulic
cylinder i is so connected to the beams as to regulate the pressure
on the briquet and it also acts as a safety apparatus. After the
briquet is formed and the pistons a, h, and b have been removed
from the molds, the mold disk e is turned by pins on its under
side engaging a cam k on the crank-shaft. When the briquet in

FIG. 11. THE DUPUY BRIQUET PRESS

the mold comes under the piston 6, it is ejected and, falling upon
a conveyer, is loaded into a car.

Another excellent press, Fig. 11, is that of Th. Dupuy & Fils,
Paris. This company guarantees to supply a plant, producing
100 tons of briquets per day, briquets weighing 13.2 pounds
each, for $14,275, external shed included. The builders calcu-
late 2 horsepower per ton of briquets produced per hour, to
which must be added 2 horsepower per ton for the several neces-
sary operations.

The presses for the manufacture of balls and egg-shaped fuel,
Fig. 12, operate on a different principle from the others. While
the briquets are sometimes piled directly into railroad cars, the
rule seems to be to discharge them from the press upon a long
conveyer, which permits them to cool and prevents a high per-
centage of breakage, which is certain to result if they are handled
while still warm.

430 TREATISE ON COKE

In 1882, the gas company at Lyons began the manufacture of
briquets from coke, employing the Dupuy machine. The coke
dust is mixed without further crushing with pitch and tar. The
impurity of coke dust requires that it shall be washed and results
in a loss of weight of 20 per cent. The washing process costs
29 cents per ton of weight before the washing, and the dust itself
being quoted at 96 cents, the washed product costs $1.56 per ton.
The complete installation of this plant cost the company about
$8,685, not including the building. The production per day of

10 hours is 6,500 briquets, the gross weight being 28 tons. For
this production there are required one foreman, one fireman, three
laborers, four boys, costing $6.84. The general expenses per day
amount to $4.52. The raw material cost is divided as follows:
washed dust, 25.3 tons, $39.66; pitch, 4,305 pounds, $28.60; tar,

1,538 pounds, $8.10; total, $76.36.
Adding thereto the cost of labor
and the general expenses, the total
daily expenses amount to $87.72.
This makes the cost of the product
$3.14 per ton. The market price
of briquets follows the price of coal,
the former being about 5 francs
(96£ cents) per ton higher than
the latter.

There is a wide difference in the
cost of manufacturing the briquets,
attributable not only to the obsolete
machinery employed in many cases,
but to the conditions under which
the coal is produced. The cost

FIG. 12. PRESS FOR MAKING EGG- j .\ . .

SHAPED BRIQUETS depends on the equipment of the

mill and the rate of wages paid.

It may be stated as a fair estimate that six workmen can turn
out 100 tons per day. The equipment of such a plant costs about
$20,000. The labor cost runs from 11 to 30 cents per ton, inclu-
ding the discharging of the coal and the loading of the briquets.
The wear and tear of the machinery is seldom less than 5 cents
per ton, and occasionally reaches from 19 to 39 cents per ton.
The expense, per ton in detail, of manufacturing the briquets
at one plant where two Bietrix presses were producing 250 tons
per day and working 24 hours per day, is as follows: superin-
tendent, $.007; manipulation of cars, $.005; discharge of pitch,
$.009; discharge of coal, $.012; crushing material, $.032; manu-
facture, $.041; loading trucks, $.015; miscellaneous labor, $.012;
firemen and engineers, $.019; total labor cost, $.152. Supplies:

011 and grease, $.017; miscellaneous, $.014; wear and tear on
machinery, $.019; fuel, at 6 francs per ton, $.010; total, $.11.
In making up this total, labor is calculated at 60 to 77 cents per

TREATISE ON COKE 431

day. In another plant, composed of Rivollier presses, the total
cost per ton amounts to 42 cents. This plant requires the services
of forty-one men, who are paid at from 60 to 65 cents per day.

The most important item in the first cost of the coal briquets
is the pitch, the price of which is twice as much in the interior as
at the seaboard. Assuming as a minimum a consumption of 6 per
cent, of pitch at a low price — that is, $5.79 per ton — the cost
under this head will be 34.7 cents. Add to this the expense of
labor and miscellaneous materials, estimated at 28.9 cents, and
we have a total theoretical cost of 63.6 cents per ton. However,
the seaboard factories usually work for the marine and employ at
least 8 per cent, of pitch in order to secure a satisfactory cohesion.
Under these circumstances the minimum cost of manufacture and
materials will reach 75.2 cents. Mr. De Graffigny furnishes other
figures, which lead him to say that a maximum of $1.698 per
ton for labor and materials should never be exceeded by a welV
organized plant.

The plant at Flers (Nord) is considered fairly representative,
and is quoted for a production of 220 tons per 24 hours. It includes
a washing apparatus for cleaning the coal, a double Bourriez
press, Pig. 13, a 50-horsepower Corliss engine, and various other
machines, tram lines, warehouses, stables, forge, ten houses, load-
ing crane, one locomotive, four cars, and cost $135,100 in 1881, not
including the land.

Mr. Robert P. Skinner, United States Consul-General, concludes
that the manufacture of briquets is of the utmost importance in
France, where the native fuel is poor in quality, and must be sub-
jected in large part to artificial treatment; also, that the produc-
tion of this fuel may be advantageously taken up in the United
States. However, he believes that, as a rule, a more direct inter-
est should be taken in studying methods of burning small coal as
such, by means of inclined fireboxes and other devices. He states
that certainly every coal company should utilize its refuse in
generating its own operating power with greater economy than
by converting it into briquets. The industries located in coal-
mining regions could advantageously adopt the same methods.
When there is a surplus of poor coal after these demands are
satisfied, the conversion of the residue into briquets may be under-
taken with assurance that if the work is scientifically carried on,
the product will sell on a plane with large coal of the same grade
and will give satisfaction.

In the spring of 1902, United States Consul Brunot, of St.
Etienne, reported as follows: "Petroleum briquets have been
manufactured in various ways in different countries, notably in
Russia, France, and the United States, as a fuel for steamships
and certain industries where rapid production of heat is desirable.
A company has recently been formed at St. Etienne for the manu-
facture of petroleum briquets that claims to have obviated all

432

TREATISE ON COKE

objections except that in regard to price. The advantages of the
product are set forth as follows:

"The briquet is composed of 97 per cent, of petroleum and
3 per cent, of hydrocarbon. The volume being equal, it weighs only,
half as much as coal and gives but from 2 to 3 per cent, of residue;
it produces no slag, it does not 'run' when lighted, and keeps
its form like coal; it burns without odor and without smoke; it

FIG. 13. BOURRIEZ BRIQUET PRESS

may be wetted with impunity, losing none of its properties; it
consumes without explosion or sparks and yet with a bright and
long flame; it may be kept indefinitely without deterioration.
By this process, a degree of saponification is obtained by which
the briquets are rendered unchangeable, even to the extent that
if a projectile should enter a ship's bunker filled with this fuel
there would be no danger whatever of explosion, the effect being
the same as in the case of ordinary coal. The average heating

TREATISE ON COKE 433

power is from 12,000 to 14,000 calories, and the briquets can be
employed in any firebox or in any grate for domestic purposes.

"The manufacture of these briquets is very simple. They are
made without heat and no danger attends the operation. The
petroleum is placed in one tank and the chemicals in another,
and both are allowed to run into a mixing apparatus, when the
chemical combination is formed immediately. The product is
then passed to a press, where the desired form is given. The
briquet is now ready for use, or it can be stored. The pressure
used in molding the forms is about 300 pounds per square inch.

"As will be seen, the mode of procedure is very simple and the
necessary plant inexpensive, requiring only tanks, mixer, and press,
with small motor power for the latter two. Works erected at a
cost of, say, $20,000 would turn out several hundred tons a day.

"The use of this chemical combination as a binder and enricher
solves a difficulty frequently encountered in the making of coal-
dust or saw-dust briquets.

"The same company manufactures what are called mixed
briquets — half coal and half petroleum; but if these are cheaper
than the former, they present less advantages, from the fact
that the density is greater and the heating power is only 9,000
calories. A steamer carrying 8,000 tons of coal would require
3,500 tons of mixed briquets and only 2,500 of the pure petroleum
briquets."

Briqueting in Germany. — United States Consul-General Frank
H. Mason, of Berlin, Germany, has reported upon the briqueting
industry in that country as follows:

Among the several branches of German industry that deserve
attention by reason of their^ economy, the recovery or utilization
of some raw material that exists unused in Germany, or because
they involve the most intelligent application of scientific knowledge
to technical processes, may be reckoned the manufacture of briquets
from brown coal, peat, and the dust and waste of coal mines.
By reason of long, careful, scientific experience, briqueting in
Germany has long passed the experimental stage and become a
standard commercial industry. Briquets form the principal domes-
tic fuel of Berlin and other cities and districts in Germany. They
are used in locomotives and other steam fires, and are employed
for heating in various processes of manufacture. Like most other
important German industries, the briquet manufacture is controlled
by a syndicate, which includes among its members thirty-one firms
and companies, and which regulates the output and prices for each
year. The official report of this syndicate for 1901 gave the total
output of briquets for that year as 1 ,566,385 tons, and in this connec-
tion it is interesting to note the distribution of this output : 749,208
tons were taken by German railways; 124,380 tons were sold to
retailers; 497,136 tons were sold to factories and works of various

434

TREATISE ON COKE

kinds; and 149,089 tons were used by German merchant steamers
and the navy, or exported to German colonies or neighboring
European districts.

United States Consul Walter Schumann reported that during
the year 1900 the production and home consumption of briqueted
fuel, in Germany, were as follows:

Production
Long Tons

Home
Consumption.
Long Tons

Bituminous briqueted fuel

1 970 316

1 849 916

Lignite briqueted fuel

1 025 000

878 910

Consul-General Mason continues as follows: The following
tabulated statement shows the production, the sales of the syndi-
cate, and the mean price per ton from 1891 to 1901, inclusive:

Year

Production
Tons

Sales of Syndicate
Tons

Price Per Ton

1891

482,495

202,780

$3.02

1892

533,075

516,508

2.49

1893

694,025

645,144

2.16

1894

745,414 '

719,258

2.10

1895

796,363

780,185

2.16

1896

830,985

817,300

2.22

1897

943,732

934,221

2.38

1898

1,078,113

1,245,269

2.43

1899

1,530,816

I,485yl30

2.34

1900

1,563,928

1,519,811

2.92

1901

1,566,385

1,560,230

3.17

German briquet factories are divided, in respect to crude
material employed, into two general groups: those that make
household briquets from brown coal (lignite) or carbonized peat,
and those that produce the so-called "Industrie briquets," using
as basic material coal dust or slack, the waste of bituminous
coal mines.

Household briquets, as made in Germany from brown coal,
peat, and to a small extent from anthracite dust, are used in
grates, heating stoves, cooking stoves, and ranges, and constitute
the principal household fuel of Berlin and other German cities.
They are cheaper in Berlin, ton for ton, than anthracite or good
bituminous coal. The standard household briquet is about 8
inches in length by 4 inches in width and 2 inches thick, and is
retailed and delivered in Berlin at about $2 per thousand in sum-
mer and $2.50 in winter. They are made largely from brown coal
at factories located mainly in Silesia, Saxony, and in the Rhine

TREATISE ON COKE

435

provinces. There are in Germany 439 brown-coal mines, which,
in 1901, produced 44,211,902 tons of lignite. Of this whole number
of mines, 181 have each from one to six briquet factories, in each
of which from one to ten presses are employed. The whole brown-

FIG. 14. ZEITZ BRIQUET PRESS

coal briquet industry of Germany includes 286 factories, with a
total of 691 presses.

Industrial briquets are used in Germany for firing locomotives
and other steam boilers, for smelting and reverberatory furnaces,
and for many other kinds of industrial use. They are made of

436

TREATISE ON COKE

bituminous coal dust, held together by a matrix of mineral pitch.
Pitch of this quality costs in Germany from $10 to $12 per
metric ton.

Anthracite is so sparingly produced in Germany that the use
of hard-coal dust for briquet purposes is relatively unimportant.
Experts have agreed that, with a mixture of from 4 to 8 per cent,
of matrix, the manufacture of anthracite briquets that will bear
transportation by sea or land in any climate presents no technical
difficulty. While Germany is preeminent in the scientific utili-
zation of lignite and peat as material for prepared fuel, it is not
apparent that this technical superiority is so absolute in the -treat-
ment of coal dust. It is true that the coal-briquet manufacture
is fully organized and developed in Germany, that there are several

FIG. 15. BRIQUET PRESS USED IN SAXONY

German builders of coal-briqueting machinery, who are masters
of that branch of construction, but the same is true of France
and Belgium.

Lignite varies in its value or adaptability for briqueting pur-
poses according to its geologic age, hardness, and the percentage
of water contained. It is for this reason that Austria-Hungary,
which has comparatively a very old and hard brown coal that
contains from 26 to 28 per cent, of moisture, has practically no
supply of briquets from that source. The German lignite, on the
other hand, is of much more recent formation; it contains from
46 to 52 per cent, of water, and is usually so soft that it can be
cut with a spade. The ideal proportion is about 45 per cent, of
water, so that German lignite contains rather too much, while
Austrian contains most too little, though this latter difficulty has
been practically overcome by steaming.

TREATISE ON COKE

437

Fig. 14 shows a Zeitz briquet press that is very largely used in
Germany. Pressure is exerted from both sides at the same time
and the mold can be exchanged without removing the mold disk.
Fig. 15 shows another form of briquet press adapted for all of
the usual forms of briquets and made by the Konigen Marienhutte
Actien-Gesellschaft, of Cairnsdorf, in Saxony. Fig. 16 shows the
pressroom of a briquet factory containing three presses with a
daily capacity of 3 tons.

A typical example of a German briquet factory is shown in
Figs. 17 and 18. This factory is located at Lauchhammer, about
80 miles south of Berlin, on the direct line to Dresden, and is of

FIG. 16. PRESSROOM OF BRIQUET FACTORY

the latest and most approved construction. It has eight presses,
with the necessary pulverizing, heating, and drying plant, run by
electric motors with current generated by steam generated with
wood from the mines. The whole is under handsome and sub-
stantial buildings of brick, stone, and iron, that cost — with tracks,
switches, and full equipment for handling raw material and load-
ing the briquets into cars — $371,000, of which $178,500 was paid
for machinery. Each press weighs 32 metric tons and stamps
out 100 to 120 briquets per minute, or 70 tons in a double-turn
day's work of 20 hours. The heating and drying apparatus for
each press weighs 18 tons. The power required for each press
and drier is 125 horsepower, and both the drier and jaws of the

438

TREATISE ON COKE

439

press, between which the briquets are squeezed at enormous
pressure, are heated by exhaust steam from the Corliss engine in
the power house, the whole supply for the eight machines being
equivalent to about 150 horsepower. Thus equipped, the plant at
Lauchhammer turns out from 500 to 600 tons of briquets per day,
which sell on cars at the factory for from $1.66 to $2.14 (7 to 9
marks), according to season and market, with an average of $1.90
per 1,000 kilograms, or metric ton of 2,204 pounds.

The cost of manufacture per ton of briquets in Magdeburg in
1903, depending on the material and the percentage of water con-
tained, was stated by Consul Walter Schumann to be approxi-
mately as follows:

Materials

From lignite taken from the open working under good
conditions, with water content of about 46 per cent. :

In large briquet factories $1.14 to $1.29

In small briquet factories 1.19 to 1.33

From lignite taken from open working, with water con-
tent of more than 46 per cent, in large briquet fac-
tories 1.33 to 1.62

From lignite taken from the deep working, with water
content up to 46 per cent. :

In large briquet factories 1.31 to 1.62

In small briquet factories " 1.62 to 1.74

From lignite taken from the deep working, with water
content of more than 46 per cent., in large briquet

factories : 1.66 to 1.86

From heavy air-dried peat, with 30 to 40 per cent,
water, reckoning the peat at 66 to 71 cents (2.8 to 3
marks) a ton :

In briquet factories with one press 1.66 to 1.95

In briquet factories with two presses 1.66 to 1.86

From a lighter air-dried peat, with 30 to 40 per cent.

water, reckoning the peat at 71 cents (3 marks) a ton. 2.14 to 2.38
From sawdust of soft wood, with 30 to 35 per cent,
water, reckoning 1 ton of this material at 47 cents
(2 marks) in briquet factories with one press. ........ 1.62 to 1.71

From sawdust of hardwood, with 30 to 35 per cent,
water, reckoning 1 ton of this material at 47 cents
(2 marks) in briquet factories with one press 1.48 to 1.62

Cost

In the case of materials containing from 15 to 18 per cent,
water, for which a drying process is not necessary, the cost of
manufacture is considerably lower.

Peat as a material for fuel ranks in natural order below lignite,
in that it is of similar, but much more recent, geologic origin, con-
tains more water, is but slightly carbonized, and has a correspond-
ingly lower thermal value than brown coal.

A pioneer in the invention of machinery and processes for
making compressed peat in Northern Europe appears to have

440

TREATISE ON COKE

441

been Mr. C. Schlickeysen, of Rixdorf, near Berlin. His first two
machines were of vertical construction, and were built in 1859
for a steam peat-compressing plant at Zintenhof, near Riga,
Russia, where they worked successfully for many years, turning
out daily about 80,000 pieces of wet compressed peat, which, after
drying, were used as smokeless fuel in a large cloth factory at
that place. During the ensuing 40 years, he has built peat-com-
pressing plants in Holland, Hungary, Switzerland, and at various
places in Germany, constantly improving his equipment and proc-
esses with a view of perfecting the product, cheapening its cost,
and substituting more and more automatic machinery for manual
labor, until the system so evolved may be accepted as standard
in this country.

Raw peat, as it comes from the bog, contains about 85 per
cent, water, 13 per cent, combustible material, and 2 per cent.

FIG. 19

inorganic matter. To obtain the 13 per cent, of combustible
elements in the cheapest, most direct manner, the peat is cut with
spades and shoveled into the trough of a long, sloping belt-and-
bucket elevator, Fig. 19, which carries it up and drops it into a
machine, Figs. 20 and 21, which cuts, tears, kneads, and mixes
it to uniform consistency, in which state it is forced out by a
horizontal screw into long, plastic skeins about 3 in. X 4 in. in
transverse section. These are delivered at the tail of the machine
on boards 3 feet long, which are lifted off by hand when filled,
laid on tram cars, and run out to a clear space, where they are
laid in rows on the ground; the skeins are then cut with a knife
into bricks or sections 10 inches long, which, being left to dry,
lose by exposure in ordinary weather one-half their water content
in a period of 2 weeks. The peat loses by this machine process
one-third of its bulk, so that a machine that works 742 cubic feet

442 TREATISE ON COKE

(21 cubic meters) of raw turf per hour delivers 495 cubic feet of
clean peat or 7,000 wet bricks of the size indicated, which con-
tain from 3 to 4 tons of dry compressed peat in a condition to
be used as fuel. Fig. 20 shows the inside of a press having double
cutting and mixing knives in the long horizontal cylinder. Fig. 21
shows a similar machine with a double breaker superposed. A
plant of this kind includes, besides the elevator and grinding
press, a 10-horsepower portable engine, which is fired with peat
refuse, and cars and tracks for handling the material. The whole
plant is movable, is taken bodily to the bog, set up at the farther
edge of the moor to be worked, and moved backwards as the peat
bed is excavated and exhausted. An important recent improve-

FIG. 20

ment by Mr. Schlickeysen is an excavating machine, which, in
moors reasonably free from logs and stones, digs and elevates peat
with great rapidity, thus saving the hard, wet, unhealthy work
of several men. The cost of such a plant, complete with engine,
tracks, cars, etc., ready to operate, is $4,431 (18,620 marks), and
its operation, when used without machine digger, employs 17 men
besides engineer and fireman, a total cost for labor in North Ger-
many of $28.56 per day.

A matter that has been the subject of many serious studies
and experiments in Germany is that of peat coke and secondary
products. The best results by this method are stated to be embod-
ied in a system perfected and patented by Martin Ziegler, which
gives to the manufacture of pe? t coke the dignity of a perfected
industrial process. The Ziegler method consists of carbonizing

TREATISE ON COKE

443

peat in closed ovens heated by burning under them the gases
generated by the coking process itself. Such a plant is therefore
self-sustaining, the only fuel required being coal or wood sufficient
to heat the oven for the first charge, when the gases generated by
the coking process become available. Not only this, but the heat
from the retort furnaces passes on and heats the drying chambers
in which the raw, wet peat is prepared for the ovens by drying to
the point of economical carbonization.

The peat coke produced as the primary product of this process
is jet black, resonant, firm, and columnar in structure, pure as

FIG. 21

charcoal from phosphorus or sulphur, and having a thermal
value of from 6,776 to 7,042 calories; it is so highly prized as a
fuel for smelting foundry iron, copper refining, and other metal-
lurgical purposes that it readily commands from $9.52 to $11.90
(40 to 50 marks) per ton. It is also a high-class fuel for smelting
iron ores, but as the process is comparatively new and the output
limited, it is yet too scarce and expensive for blast-furnace pur-
poses. Crushed and graded to chestnut size, it forms an excellent
substitute for anthracite in base-burning stoves. In larger lumps,
as it comes from the oven, it fulfils substantially all the various
uses of wood charcoal as a clean, smokeless fuel. The cost of a
four-oven plant, with all apparatus for cutting and drying the

444 TREATISE ON COKE

peat, distilling the gas liquor, and extracting paraffin from the
tar, is given at $95,200. Such a plant has a capacity of 15,000
tons of peat per year, the various products of which would sell,
at present wholesale market prices, for $117,596. A plant of
twelve ovens, with all appurtenances complete, would cost $261,800
in Germany, and should produce annually products worth $350,000,
from which, deducting the carefully estimated cost of peat, labor,
depreciation of property, and other expenses — $179,200 — there
would remain a profit on the year's operation of $170,800. Consul-
General Mason further stated in March, 1903, that this process
is in successful operation at Redkino, in Russia, and the German
government has evinced its practical interest in the subject by
placing at the disposal of the company a large tract of peat -moor
lands, the property of the state, on which extensive works will be
erected during the coming year.

There are several recently patented processes by which arti-
ficial coal, or briquets, have been more or less successfully pro-
duced from peat by the use of machinery, or methods, not yet
fully established on an industrial basis. Among these methods
is the Stauber, which was first brought into prominent notice
in 1901, when the Imperial testing station at Charlottenburg
announced, as the result of experiments made with peat briquets
manufactured by the Stauber system, that they contained 45.14 per
cent, of fixed carbon, 4.54 per cent, hydrogen, 29.34 per cent,
oxygen, and 9.09 per cent, ash, and had a thermal value of 3,806
calories. The Stauber system as thus applied includes a process
of rapidly drying moist peat, by means of heated and compressed
air in a closed chamber or channel, communicating with conduit
pipes in such a manner that heated air can be forced through the
drying channel and cold air through the outlet pipe; the effect
being that the cold air rapidly absorbs the hot saturated air of
the drying chamber and condenses it in the conduit pipes, thus
greatly stimulating the process of evaporation by which the peat
is dried. It is claimed for the Stauber method that it reduces
the moisture to 18 or 20 per cent, quickly, effectively, and, what is
most important, without changing the chemical composition of the
peat. The drying machine is in the boiler form, and of a size to
conveniently produce 5 tons of dried peat per day. In a large
plant this unit would be simply repeated, as a number of machines
can be worked with air-currents generated by the same engine.
A large plant for working the process was stated to be in course
of erection near Konigsberg, on the Baltic sea, and another was
already in operation at Ostrach, in Wurtemburg, in 1903. The
peat coal can be used for locomotives or other fuel raw, or it can
be coked, the coke being wholly free from sulphur, and is there-
fore as valuable as charcoal for certain industrial purposes.

Estimates furnished by the company give the cost of a plant
capable of turning out 50 tons of briquets per day as follows:

TREATISE ON COKE 445

Buildings, $14,280; machinery, $17,850; steam engine and fix-
tures, $3,570; means of transporting material and product, $3,570;
total, $39,270.

A second process is that invented by Mr. Schiilke, of Bach
Strasse, Hamburg, the salient feature of which is that the turf or
peat used is cleaned of roots, stones, etc., then liquefied by water
and pumped through a pipe line several miles to the works, where,
as claimed by the inventor, it is leached and converted by heat
and pressure into briquets at a net cost of $2 per ton, or into
artificial coal, having a thermal value of 6,250 calories, at a cost of
$2.50 per ton. It is understood that a large plant is in progress
of erection on the northern coast of Germany for the utilization of
this method, but as to the actual condition of the enterprise or
the practical value of the process on an industrial scale no exact
information is at hand.

Briqueting in Norway and Sweden. — Coal has not as yet been
discovered in paying quantities in any part of Norway, but peat
of the best quality is found in abundance, and in some places is
the only fuel used for domestic purposes. It is generally obtained
in the old-fashioned way, i. e., cut with a spade by hand.

A society, counting many prominent Norwegians as members,
has been formed for the specific purpose of utilizing the peat bogs,
which cover an area of about 3,861 square miles. The quantity
and quality of the peat varies much, of course, in the different
bogs, but some of the deposits are of the best quality and exceed
12 feet in thickness.

Peat briquets are made and burned in several factories located
where peat is easily obtained. The machinery used is built prin-
cipally on the Anreps system; some is imported and some made
at the machine shops at Aadals and Hasle Brug. Of the latter,
illustrations and descriptions follow.

The product of these machines is known as "pressed peat,"
and the process is quite similar to that of brickmaking. The peat
is dug from the bog and put into the machine, where it is ground
and then forced through a square spout out upon a moving plat-
form, where it is cut into convenient lengths. Thereafter it is
dried, either in the open air or artificially, until its volume of mois-
ture is reduced 20 to 25 per cent. It is estimated that 1.8 tons
of pressed peat equals 1 ton of soft coal, for heating purposes,
while a ton of peat made in the old way, by hand, equals only
about one-third of a ton. The total cost of cutting, drying, and
storing the peat will not, under ordinary conditions, exceed $1.60
per ton.

Fig. 22 shows a 4-horsepower, steam peat-briquet machine,
requiring a crew of six men, eight women, and two boys. It
delivers 20,000 briquets per day and costs $107. Fig. 23 shows
a similar machine to be operated by two horses.

446

TREATISE ON COKE

Attempts have also been made to manufacture coke from peat,
and a plant for that purpose was built at Stangfjord, in the neigh-
borhood of Bergen.

The partially dried peat briquets are carbonized in hermetic-
ally closed retorts by electrical heat. The process allows the peat
blocks to be carbonized within a short time and with great uni-
formity, while the peat charcoal produced consists of a dense black

FIG. 22

mass, showing the structure of the peat. The peat is first sub-
mitted to a drying and pressing operation, which is performed in
a 5-horsepower press that can turn out about 2,500 blocks of peat
per hour, the weight of each block being 4.4 pounds. The par-
tially dressed and dried peat briquets are next loaded on shelf
wagons carrying 140 pounds each. When loaded, these wagons
are pushed into the cooler end of the drying tunnel. The current
of air passing through the tunnel is heated by the waste gases

FIG. 23

from the retorts and set in motion by means of electrically oper-
ated fans. At the top end of the tunnel, where the wagons emerge,
the temperature of the air is 90° to 100° C., and at the lower end,
where they enter, 40° to 50° C. The loads of dry peat are next
taken direct into the retort house and emptied into the retorts.
102 wagons, two tunnels, three electric fans, and one hot-air stove
compose the drying plant at Stangfjord, which is said to have been
able to produce 1,000 air-dried peat blocks a day.

TREATISE ON COKE 447

The retorts consist of upright cylindrical vessels of iron about
6 feet 6 inches in height and 3 feet 6 inches in diameter, each retort
being provided with a removable cover. The retorts have spiral
resistance coils, so constructed that the peat blocks can be built
up in contact with them until the mass of peat entirely fills the
retort, the heating agent lying in the center. The top cover of
the retort is then clamped down and the electric current turned
on. Each retort is loaded with 882 to 1,102 pounds (400 to 500
kilograms) of dried machine-made peat and the coking requires
3 to 4 hours. The coke thus prepared burns with a bright flame.
This process for carbonizing peat was invented by Herr P. Jebsen,
of Dale, Norway, and it is said to be an advantageous one. It
has been in operation during 3 years and the plant is now said to be
closed on account of lack of sufficient capital.

United States Consul Victor E. Nelson reported on March 7,
1903, from Bergen, Sweden, as follows:

"It is known that Sweden possesses great wealth in her peat
bogs, which are only awaiting development. The peat produc-
tion of the world amounts at present to from 9,000,000 to 10,000,000
tons a year. Russia comes first with about 4,000,000 tons; peat is
used there for locomotives as well as in the factories. One of
the largest cotton works in the world is located in Russia, and it
uses peat exclusively as fuel. Most of the peat fuel of Sweden is
used in the homes, but some is employed for industrial purposes.
There are, for instance, in the province of Skane, two factories
using peat exclusively as fuel. The quality of the Swedish peat
is excellent, yielding an inconsiderable percentage of ashes. More-
over, the moors of Sweden are high and easy to drain. No other
European country, excepting Russia, possesses such an abundance
of good peat.

"The important question is the cost of manufacture. Accord-
ing to one calculation (in 1901) this is on an average of 81 cents
(3 kronor) per ton for unsheltered peat, to which must be added
27 cents (1 'krone) per ton for transportation and shelter. This
would make the cost of the peat at the place of consumption
$1.07 per ton, which is equivalent to coal at $2.14 per ton. For
machine-made briquets, the rate (free on cart from the moor)
was $1.34 to $1.61 per ton.

"Compared with the present prices for wood and coal, peat is
unquestionably the cheapest fuel. One cord of pine wood must
not cost more than $1.07 if it would compete with peat at the
above-mentioned rate. If 1 ton of hard coal is equal in fuel
value to 1.8 tons of peat (the trial results vary between 1.6 and
1.8), the calculated peat price would be equal to a coal price of
$2.89 per ton — a price at which coal cannot be bought in Sweden.
The government railways, which are the largest consumers of coal jn
this country, and consequently are able to buy cheap, have, during
many years, paid on an average $3.75 per ton at the port of landing

448 TREATISE ON COKE

"The government and parliament manifest comprehension of
the great importance of the peat industry. The trials of firing
with peat on the Swedish government railways, have, according to
the official report, shown that peat is about as expensive as Eng-
lish coal, when the rate is $2.50 for the former and $4.29 for the
latter, exclusive of freight charges and the cost of loading on the
tenders of the locomotives."

Engineer Alf Larsson, at a meeting of the Association of
National Economy, at Stockholm, in a lecture on "The Use of
Our Peat Bogs," is reported to have stated as follows:

"Russia yearly produces 4,000,000 tons of peat, and the
Russian Government receives $938,000 per annum for leasing
peat bogs; Germany produces 2,000,000 and Holland 1,000,000
tons; Austria, Denmark, Iceland, and other European countries
also utilize their deposits of this cheap fuel; here in Sweden the
production of peat for fuel is about 1,000,000 tons a year.

"Peat can be recommended as a very good fuel and its prepa-
ration gives employment to many persons in this country. Near
Falkoping, for instance, about 1,000 persons are each summer
employed in the industry. Peat can also be utilized as fuel by
the paper mills, glass works, ironworks, brick kilns, and especially
in the households. The government engineer for the peat industry
estimates the supply of peat in Sweden to be 4,000,000,000 tons.
The peat question is at present the most important problem
in Sweden. The government has done some experimenting in
the matter, with good results, but very much remains to be
accomplished."

Briqueting in Great Britain. — Coal briquets for household use
were first made in 1877. For many years the industry has
been chiefly carried on in Wales, where the coal screenings are
better adapted to this use than any other quality of coal produced
in the United Kingdom. Fuel briquets are made to a limited
extent in England and Scotland. The immense peat bogs in
Ireland, stated to comprise one-tenth of the whole country in
area, should warrant attention being given to the mechanical
preparation of this fuel in the near future.

Reports from consuls show a moderate condition of the manu-
facture of briquets in England. Liverpool manufactures 2,000
to 3,000 tons annually at a cost of $4.87 (20 shillings) per ton,
from bituminous coal dust. In Manchester, the few briquets used
are made by the Whitefield Colliery Company, of Staffordshire.
They are about the size of an ordinary brick, and their chief
component is coal dust (slack), with a little tar added. The price
at this place delivered was $2.43 (10 shillings) for 300 briquets, in
December, 1902. At Sunderland, the Wear Fuel Works Company,
Limited, at one time made briquets. The annual output was
in number from 50,000 to 100,000. The materials used were

TREATISE ON COKE 449

bituminous-coal dust and pitch, the latter for combining purposes.
The briquet presses were mainly constructed by the company
itself, and two kinds were used — trough and table. One of the
briquets that was manufactured by this company evaporated 14.4
pounds of water at 212° F., while the best North Country steam
coal averages 14 pounds of water to 1 pound of coal. The selling
price of this fuel was generally equivalent to that received for the
best coal. There are a few other places in England in which
briquets are produced in a small way; evidently, this manufacture
has not yet attracted the attention of coal operators.

In the latter part of 1902, briqueted fuel was only produced
in the Edinburgh district at the gasworks completed by the Edin-
burgh and Leith Corporations Gas Commissioners, at Granton, a
suburb of Edinburgh. At these works, briquet machinery was
utilized for the purpose of working up the coke sif tings into fuel.
This residuum of gas production heretofore was wasted. This
briquet plant was erected at a total cost of $5,000, the price of
the machine being $2,250. The press used is known as the John-
son type, Fig. 24, manufactured by Wm. Johnson & Sons, Leeds,
England. It had a capacity of 5 tons per hour. The coke siftings
were mixed with pitch and fed to the press, the briquets being
pressed on both sides simultaneously, the pressure applied equal-
ing about 2 tons per square inch. The plant worked satisfactorily,
barring the tendency to clog when the material was a little too
wet. The briquets weighed 4 pounds each, and were ready for
immediate use as fuel, although it improved them somewhat to
lie a week or 10 days in the open air. It was the original inten-
tion to use these briquets in the furnaces of the gasworks, but it
was found to be better economy to place this fuel on the market
for household purposes at $2.50 per ton, which price yielded a
good profit. The Johnson press is said to be adapted, also, to
lignite, bituminous coal and anthracite, charcoal, and peat.

Ever since they were introduced, briquets have been on the
market in East Scotland. During the last 10 years, however,
the consumption has gradually fallen off. Colliery owners in dis-
tricts where the coal is all bituminous, who installed briquet plants,
stopped the manufacture some years ago, as the local demand was
not sufficient to warrant its continuance, especially in competition
with large producers in West Scotland and North England.

Briqueting in Wales. — Consul Daniel T. Phillips writes from
Cardiff, Wales, December 24, 1898, as follows:

"The manufacture of coal briquets known as patent fuel is
conducted on an extensive scale in this consular district and else-
where on the seaboard of the South Wales coal field, and, along
with the general coal trade, is making headway every year. The
first shipment at Cardiff was in the year 1859, when 4,700 tons
was exported; and last year the total reached nearly 400,000 tons,

450

TREATISE ON COKE

to which must be added shipments from Newport and Swansea,
augmenting the quantity named about 50 per cent. In fact, all
the fine coal not used in the manufacture of coke — for which, by
the way, the harder fine coals are not suitable — is utilized in
making patent fuel, most of which is manufactured in this district.

FIG. 24. JOHNSON BRIQUET PRESS

The exports are chiefly to European ports, at certain of which
briquets are also made on the spot from the imported coal.

"A local manufacturer, Mr. T. E. Heath, says that thirty odd
years ago the 'Coulliard' or ordinary French process was intro-
duced into Cardiff, and, being found mechanically much more

TREATISE ON COKE 451

perfect than the old process — which was both slow and costly-
soon became general. The great majority of fuel works here and
abroad are merely modifications of the Coulliard. When the
fuel is wanted for immediate use, it would be difficult to get a
better; but a great objection arises from the steam being injected
into the pug mill instead of having the mixture dried and heated
by hot, dry gases. The steam condenses in the mixture of coal
and pitch, and the blocks, when pressed, contain, therefore, not
only the original moisture, very much increased in wet weather,
but also the condensed steam that has been used to heat the
mixture. As the blocks come from the press, and for hours after-
wards, they are visibly giving off vapor, and this goes on in dry
weather until the briquets become more or less porous; conse-
quently, if it rains, as is usually the case, and they are afterwards
exposed to frost, they fall to pieces. Such fuel cannot be stocked
without disintegration and considerable loss of calorific value;
whereas, fuel made by a dry-heat process, which drives out the
original moisture instead of adding to it, will remain for an indefi-
nite period as sound as on the day it was manufactured. In fact,
the fuel is thus superior to the best Cardiff steam coal, which
loses, by exposure, more or less of its evaporative efficiency, as
the pitch in the dry-heat fuel prevents the ingress of moisture
and the egress of gases.

"In this district, not so much attention is paid to the mechan-
ical preparation of the coal used in briquet manufacture as in
the varous districts on the continent of Europe, where the coals
are of a much poorer quality than those mined in South Wales.
Once the due proportion of pitch for any class of coal has been
found, the question of mixing becomes simple. A briquet is a
compressed mixture of fine coal and pitch. The quantity of the
latter varies according to the bituminous matter in the coal; the
greater the amount of bitumen present, the less pitch is needed.
The former, being adhesive, performs to some extent the same
function as the latter; but the average proportion of pitch used
is from 7 to 9 per cent. The preparation of the coal is limited to
screening at the colliery and afterwards reducing it to as fine a
condition as possible in a disintegrator, from which it is conveyed
to the mixer. Here it meets the pitch, and is then taken to the
heater. In each process, the coal and pitch are intimately inter-
mixed. In what is termed the melted-pitch process, the pitch is
melted (sometimes with additions of common tar) prior to being
added to the coal. In the dry method, which finds more favor,
the pitch is ground up with the coal in a dry state, both being
heated as nearly as possible to the firing point of the pitch, in an
externally heated chamber, until each particle of coal is covered
with a film of melted pitch and so rendered fit, for compression
into blocks. The mixture of paste is said to contain from 3 to 5
per cent, of moisture, in order to facilitate the sliding of the

452 TREATISE ON COKE

particles of coal on each other during compression; but, manifestly,
the heat causes such moisture to be thrown off quickly. After
having been thoroughly mixed, the whole passes out of the cham-
ber into a bin, whence it is conveyed in buckets of suitable size
by means of an endless chain or belt to the press.

"The compressing machines used may be roughly divided into
three classes, irrespective of the nature of the power employed.
These classes are: First, the single-compression machines, under
which head should be placed the 'Mazeline,' 'Stevens,' and
'Dupuy' presses; second, machines compressing on both sides
of the briquet, such as the 'Middleton,' 'Bietrix,' and 'Veillon';
third, machines acting by the tangential pressure of rolls, like
that of 'Fouquemberg,' and those of the sausage-machine type,
such as the 'Bourriez' press.

"As far as this district is concerned, the single machines appear
to be common and the shape of the briquet is rectangular. The
best-looking kind that I have seen is the 'sausage,' being about
5 inches in diameter and to all appearance a solid piece of bright
carbon. The rectangular blocks chiefly exported weigh from
20 to 25 pounds; and, as some markets demand smaller sizes, a
division plate is inserted in the mold employed for the larger size,
thus reducing it by one-half. For obvious reasons, the 'ovoid'
form of briquet is common, because, there are no corners to chip
off in the handling.

"Hot from the press, the briquets have little cohesion, and
must therefore be treated with care in stocking and in loading.
The endless belt saves a deal of labor both at the factory and at
the ship's side, the donkey engine in the latter case being utilized
in working an endless 'hopper' at the side of the vessel, so that
while one laborer is putting briquets on at the bottom, another
laborer is employed in taking them off at the top and handing
them to the loaders on the vessel.

"Inquiries as to the cost of labor, fuel, supplies, and mainte-
nance of a briquet factory show an average of half a dollar per ton,
exclusive of the cost of materials.

"It should be noted that almost any resinous or tarry matter
may be used. For instance, seaweed boiled in water for some hours
produces a glutinous mass, and acts as a good binding material
if mixed with the coal dust in the pan. Again, fine sawdust, in
the proportion of 7J per cent., mixed with the coal dust before
going into the pan, improves the quality of the briquet. Of course,
the quantity of each binding material can be best ascertained by
experiment. Locally, 'soft medium' pitch is used. Pitch, being
a waste product, is subject to fluctuation, both in quantity and
in price; and at times a pitch famine, as in the year 1895, sends
the price so high as to make the manufacture of patent fuel
unprofitable. The inventive American has here an opportunity
to make a fortune by providing a satisfactory substitute for pitch.

TREATISE ON COKE 453

Such substitutes as have been tried are said to have added 1 or 2
per cent, of ash, and, besides, the fuel made by them goes to pieces
in the first shower of rain.

"In many parts of our coal -producing states, immense dumping
grounds of unused fine coal might be utilized; and the one reason
given by coal operators for not turning their attention to artificial
fuel is the scarcity of pitch. This would not apply generally, and
where pitch is obtainable at a moderate cost, it is to be hoped that
immediate attention will be paid to this manufacture, and that else-
where serious efforts will be made to invent a substitute which can
be produced in unlimited quantities at a comparatively small cost.

"It is claimed for patent fuel that it is about twice as hard as
coal and, in some works, the minimum cohesion allowed is 83 per
cent, of lumps to 17 per cent, of dust, the test being made in a
revolving apparatus in which square chunks of fuel are picked
up and let fall upon an iron bar screen. According to Mr. Heath,
large coal in similar chunks, tested in the same machine, gives
only 40 per cent, of lumps and 60 per cent, of dust; and he tells
of a cargo of fuel, the cohesion of which was 83.10 per cent., shipped
for a long voyage to a hot climate, which had a breakage of only
2.13 per cent, and a wastage of .88 per cent., although the ship-
ment was made in very wet weather.

"With regard to calorific qualities, local experiments cited by
a Mr. Colquohoun show, in three tests, 8.41 pounds, 8.77 pounds,
and 8.99 pounds, respectively, as the weight of water evaporated
from 1 pound of fuel at 212° F., the average evaporative power of
several of the best Welsh steam coals being 9.33 pounds; so that
the artificial fuel is almost equal in this respect, besides occupy-
ing less space.

"In order to compete with Cardiff in the South American trade,
advantage should be taken of local experience in briquet manu-
facture. Those who intend to enter the patent-fuel trade will
find several firms iri South Wales prepared to accept orders for
complete plants. One well-known firm is the Uskside Engineering
Company, the managing director of which is a Mr. A. J. Stevens,
who has had considerable experience in this line, the postal address
being Newport, Monmouthshire.

"As to the cost of the fuel here, I can only say that the
market price is determined by that of coal itself, the normal
figure being slightly under $2.50 per ton, or about 50 cents below
the present figures. In conclusion, I desire to emphasize the
desirability of establishing the manufacture of patent fuel in the
United States, as I foresee that it will be developed into a most
important industry."

Briqueting in Canada. — A number of conditions have encour-
aged fuel briqueting in Canada, particularly in the Province of
Ontario where there are practically no deposits of coal, and, on

454 TREATISE ON COKE

the other hand, where there are peat bogs of greater or less
size widely distributed. What Ontario lacks in coal beds is made
up by her wealth of peat bogs, which, in extent and wideness of
distribution, are probably not exceeded by those of any other
country of equal area. There is practically no fuel briqueting in
other parts of Canada. In addition to the abundance of peat in
bogs, the briqueting industry has been stimulated by a scarcity of
anthracite and bituminous fuel, on the occasion of strikes in coal
fields supplying Ontario with these forms of fuel. Also, the splen-
did hardwood forests of Southern Ontario have been almost
destroyed, making it necessary to depend on other sources than
wood for fuel. Among those who have been particularly instru-
mental in placing the peat manufacture on its present high level
in Ontario, are Mr. Alexander Dobson, of Beaverton, and Mr.
J. M. Shuttleworth, of Brantford; also, Mr. A. A. Dickson, of
Toronto.

It is stated that the European practice, although successful
under special circumstances, notably cheap manual labor, cannot
be profitably followed on this side of the Atlantic. Only bogs of
an average depth of 4 feet and upwards and of considerable area
(at least 100 acres), should be selected, on account of the expense
of the briqueting plant. Two principal systems are defined in
making machine peat, depending on the treatment of the raw
material immediately on raising it from the bog. One plan is to
digest the peat, with the addition of water, into a liquid mud,
which is then poured into molds in the open air, and after losing
some of its water, divided into blocks and allowed to dry. This
product is sometimes called "knead" peat. The other, and more
commonly employed process, consists of grinding or mincing the
peat, as it comes from the bog, into a soft, plastic mass, which is
then cut into bricks and dried.

Among the prominent peat bogs in Ontario are the Welland
and the Beaverton bogs. The Welland bog is about 6 miles from
the town of Welland on the Welland Canal, and is owned by the
Peat Industries, Limited, of Brantford. It covers an estimated
area of 4,000 acres, and varies in depth from 3 to 7 feet, averaging
probably 5 feet. The Beaverton bogs cover an area of about
100 acres near the town of Beaverton, and are owned by Mr.
Alexander Dobson, of that place. The factories at these two bogs
are characteristic of peat manufacturing plants in Ontario, and
a brief description will be given of the methods in use at them.

The three divisions in which may be grouped the various
operations comprising the making of fuel peat by what we may
call the Canadian process are: (1) excavating; (2) drying;
(3) compressing. Various methods are adopted for carrying on
all these operations according to the nature of the bog and other
controlling circumstances; but it cannot be too strongly stated
that the crux of the manufacture lies in drying the raw material.

TREATISE ON COKE

455

The difficulty consists not merely in getting rid of the water, but
getting rid of it at reasonable cost. It is at this point that num-
berless promising processes have broken down, and it is this essen-
tial feature of manufacturing that requires unceasing vigilance
on the part of the peat maker
if his product is to be satis-
factory.

Peat bogs are of two
classes, wet and dry. In a
permanently wet bog, the peat
is submerged in water that
does not admit of being
drained away. A dredge
floating on the bog excavates
the peat in trenches, and then
follows into the paths thus
cut for itself; scows accom-
pany the dredge, each carry-
ing a number of boxes in
which to load the peat. The
scows are towed to a point
from which the boxes are con-
veyed to the works where the
peat is to be treated.

For dry bogs, different
methods are required. The
word "dry" as applied to a
peat bog does not mean the
absence of water, but rather
that the bog is not submerged
and is capable of being
drained. The first thing to be
done is to get rid of the sur-
plus water, for which purpose
drains or ditches must be dug.

At the Welland bog, the
following system has been
adopted: Two or more par-
allel drainage ditches are run
through the length of the bog
660 feet apart and 10 feet
wide. They are sunk through
the peat into the clay under-
lying the bog, and conduct
the water to the county ditch with which they connect. A series
of cross-ditches is now run at right angles to the first, intersecting
them at intervals of 50 feet until a plot of working area 660 feet
square, or 10 acres in extent, has been ditched and drained.

456 TREATISE ON COKE

At nearly all of the other bogs in the province where peat-fuel
manufacture has been attempted, drainage has been necessary,
the expense per acre varying with the depth and size of the drains.
After draining, the light, growing, or undecomposed moss is
removed, together with protruding stumps and roots of trees, and
a level surface is prepared for the digging or excavating process,
which comes next in order. The laying of light tramways on
which to haul the peat into the factory is the next preliminary.

Usually the first step in the actual harvesting or gathering of
the peat is to run an ordinary farm harrow over the surface and
expose a thin covering of peat to the action of the wind and sun.
This plan is employed where stumps and roots are numerous, as
on the Welland bog. When dried down to a water content of
about 45 per cent, the peat is scraped by hand over to the tram-
ways and loaded into cars to be transported to the factory.

At the Beaverton works, the peat is conveyed from bin or
stock pile or deposited directly from the tram-car. The air-dried

FIG. 26. PEAT DIGGER

peat passes into the hopper of the "breaker" or disintegrating
machine, where it is subjected to a manipulation that breaks up
the peat fibers, thus permitting the remaining moisture to be more
readily liberated in the drier. Dobson's drying machine, Fig. 25,
consists of a circular sheet-iron box, incasing a horizontal shaft
from which project radial cast-iron arms about 1 foot in length.
The Dobson drier is the distinguishing feature of the Beaverton
works. The principles it embodies are: Applying the greatest
heat to the exterior of the upper end of the cylinder where the
damp peat enters; causing the flames and hot gases to pass along
and about the outside of the revolving cylinder, to the lower or rear
end before entering, and then to pass back through the interior of the
cylinder, traversing the showering peat; arranging an internal sys-
tem of lifters so that this showering of the peat will be continuous
and uniform from side to side of the cylinder ; slightly pitching the

TREATISE ON COKE

457

cylinder so that, as it revolves, the peat will travel slowly toward
the discharge end; and so adjusting the firing in accordance with
the proportion of water present in the peat that a product uniform
in moisture content will be the result. One test of this drier for a
day of 10 hours gave the following results : Weight of air-dried peat
charged into drier, 29,300 pounds, containing 34.21 per cent, water;
weight of peat discharged from drier, 23,000 pounds, containing 16.61
per cent, water. The weight of water evaporated was 6,300 pounds.
The Beaverton method of excavation is entirely different.
After the bog is drained and leveled, a mechanical and electrically

FIG. 27. DICKSON BRIQUET PRESS

driven digger, Fig. 26, is set at work, which travels slowly up and
down one or both sides of the area under removal, the excavating
device working in the side or wall of the ditch.

At Beaverton, this excavator, or harvester, digs, pulverizes,
and spreads the peat at one operation, only one man attending to
a 15-horsepower motor, which handles from 100 to 150 tons in
10 hours. The harvester consists of an endless chain with special
buckets and cutters, which cut the peat the entire depth of the
bog and elevate it to a point about 8 feet above the bottom of
the bog. The machine is so arranged that it can cut any depth
down to 4 feet, the depth being easily controlled by the raising

458

TREATISE ON COKE

or lowering of the lower end of the case containing the endless
chain with the cutters. The spreading of the peat on the dry
top of the bog is the most important part of the work, as tests
show that the moisture can be reduced to about 36 per cent,
after several hours' exposure on a good drying day. The whole
machine, the harvester and spreader combined, is driven by a
G-horsepower electrical motor. The rate of travel is from 3 feet
to 3 feet 6 inches per minute, and the width of the cut is 12 inches.
Loading the air-dried peat and tramming it into the factory com-
plete the field operations as practiced at Beaverton.

The final step, in the Canadian methods of peat-fuel manufac-
ture, is compressing the dried and powdered peat into blocks or
bricks. It has been found that a cylindrical briquet, about 2
inches long and about the same in diameter, best answers require-
ments, and this shape is also a convenient
form for manufacturing.

The original briqueting apparatus
employed in Ontario was of the open-
tube type patented by Mr. A. A. Dickson,
and known by his name, Figs. 27 and 28.
It was first set up at Well and about 12
years ago, and since then the many
modifications and improvements made
by the inventor from time to time have
been tested there. The principle of this
press lies in the fact that if a tube of
indefinite length be fed with any mate-
rial, the resistance due to the friction
between the material and the tube will
gradually rise until no more can be forced
in. Peat is of such a nature that, when
once caused to pack in the tube, continued pressure on the mate-
rial generates a rapid and great increase in the frictional resistance.
At the Beaverton works, the discharge pipe from the drier
empties into the shoe of an elevator, which carries the dried peat
into the large galvanized hopper or bin interposed between the
drier and the briqueting press. This reservoir serves several
important purposes, and is practically indispensable. It permits
of a reserve supply in case of accident to the drier; allows the
dried peat to cool; and enables the press attendant, by drawing
from various parts of the bin containing material differing in
degree of dryness, to send to the press a supply of peat practically
uniform in water content.

The resistance block press in use at Beaverton is the result
of 4 years' experiments carried on by Mr. Dobson. The press
embodying Mr. Dobson's own idea on the plan of the Dickson
press, is in use at the Beaverton plant. In the Dobson press,
Figs. 29 and 30, friction is almost entirely eliminated, each die,

FIG. 28

TREATISE ON COKE

459

previous to being recharged, being oiled to prevent friction of the
peat against the die wall in the subsequent expulsion of the briquet.
A number of dies are employed in this press, allowing the briquet
to remain in each die during one cycle ; it is then subjected to pres-
sure and expelled. The following is a description of the machine:
There are two punches in each machine and to each punch a die
block containing eight snugly fitting dies. The down thrust of
the punches is imparted by two heavy eccentrics faced with roller
bearings, and with each stroke of the punch the die block is turned

FIG. 29. DOBSON BRIQUET PRESS

through one-eighth of a revolution. Working in the next die to
the compressing punch is the release punch, which expels the
finished briquet, while the third receives an oil swab that coats
the inside of the die with a film of crude petroleum, to lessen the
friction and facilitate the expulsion of the briquet.

The two punch systems of the press act reciprocally, a stroke
being delivered at every half revolution of the eccentric shaft.
With each down stroke, the compressing punch forms a briquet
on the top of one previously made in the same die, the discharging
punch expels from the next die the bottom or completed briquet

460

TREATISE ON COKE

and the third die receives the coating of oil from the oil swab.
It makes 50 or 51 revolutions per minute, producing 100 or 102
briquets per minute. Twenty-five briquets weigh about 10 pounds,
and consequently the output of the press in 10 hours is about 12^
tons finished fuel.

We now take up the cost of manufacturing the briquets,
both at Welland and Beaverton. At Welland the workable depth

PLAN, with left-hand die k>/ocK removed

CLEVATION

Left half, with cf/e */oc* '»Place
vertical sect fan through A- 5

FIG. 30

of the bog is 3 feet as against 2^ feet at Beaverton, which gives
an advantage to the former in price per ton of fuel; also, at Wel-
land the capacity of the two briqueting presses is considerably
greater than that of the one at Beaverton, while at each the
expenditure for labor is about the same.

TREATISE ON COKE

461

At Welland, 17J tons of briquets per day cost as given in the

following table :

COST AT WELLAND

Field operations

Attendance on drier. . .
Attendance on presses.
Power

Total

Per Ton

$.3771
.1650
.2171
.2113

$.9705

Wages have gone up since the Welland tests were made, and
laborers now get at least $1.40 per day. This advance will add
proportionately to the cost of manufacture.

At Beaverton, 12^ tons of briquets per day cost as shown here-
with:

COST AT BEAVERTON

Per Ton

Field operations .

$.3911

Drvintr

.3673

Brioueting ••

.2512

Total

$1.0096

In neither case do the above figures cover more than actual
operating costs, nothing being allowed for interest on capital
invested, wear and tear of machinery, royalty charges, or profits.

COST OF PLANT

Machinery, Etc.

Cost

Brio net press

$2 500

Drier . ... . .

1 350

Breaker

400

Excavator including motor

600

Generator tram car motor and tracks

1 200

Engine and boiler 50 horsepower

2 000

Shafting belts and conveyers

700

Buildings (brick)

1 500

Sundries

200

Total

$10 450

The above is the cost of the plant according to the Beaverton plan ,
with a capacity of 3, 000 tons of briquets per year, working 10 hours per
day, or 6,000 to 7,000 tons when run continuously 24 hours per day.

462 TREATISE ON COKE

In the following figures an attempt is made to include all items
of cost such as those for depreciation, interest, etc., which can only
be approximate.

TOTAL COST OF BRIQUETS

Manufacturing

Cost of bog

Depreciation of plant.
Interest on capital. . .
Royalty

Total

Per Ton

$1.0000
.0180
.3483
.1741
.2500

$1.8000

The price at which this Beaverton product sold at the factory
in 1901 and part of 1902 was $3 per ton.

It is necessary at these plants, for the continuous operation
of the works the year round, to harvest, semidry, and stack
during the summer a sufficient supply of peat for the months
when harvesting is impossible. Another fact in connection with
peat-fuel briquets is that the manufactured product must at all
times be kept dry. Contact with water renders the peat practi-
cally valueless as fuel; hence, the care in preparing and housing it
is of the utmost importance.

Briqueting in the United States. — The United States of North
America has been so amply endowed by the Creator with excellent
mineral fuels, covering areas aggregating 344,450 square miles,
that thus far very little attention has been given to the utilization
of coal waste, screenings, bog carboniferous mud, and other com-
bustible matters, in their manufacture into briquets. With this
great abundance of good mineral coal so widely distributed, it
may be submitted, as a general principle, that from its moderate
cost, ranging from $1.50 to $6 per ton, it is evident that, except
in special localities, the manufacture of combustible matters into
briquets could not be made with profit in competition with the coal.

Efforts have been made in Canada to briquet bog material,
as already described, but at the low rate of manufacture there
attained, on account of the reduced heating power of peat briquets
as compared with coal, the latter would command the preference
in the United States.

Some efforts have been made to manufacture briquets from
coal screenings and coal dust, but these so far have not been dis-
tinguished as successful enterprises. Even with coal screenings
at 50 to 60 cents per ton, using 6 to 10 per cent, of pitch for bond-
ing matter at $12 to $13 per ton, with the necessary labor in
preparation and manufacture, the cost of briquets would prob-
ably reach $2.25 to $2.75 per ton.

TREATISE ON COKE 463

At the Hazleton meeting of the American Institute of Mining
Engineers, in October, 1874, a Mr. Loseau exhibited some egg-
shaped briquets made from anthracite culm or waste screenings,
but this exhibit failed to impress its value at that time. Undoubt-
edly, thousands of tons of this culm have been wasted. This
material affords when washed the best substance for the manu-
facture of briquets, especially for domestic uses. Even now it
offers a practicable field for this industry. The culm produced from
the usual annual output of 50,000,000 tons of anthracite affords an
ample supply of this material for several briqueting plants.

About the year 1890, the Lehigh and Wilkes-Barre Coal Com-
pany, at Audenreid, Pennsylvania, installed a large briqueting
plant to make briquets from anthracite culm. The culm was
received in a large storage bin, from which it was elevated to
an automatic mixer, into which 5 to 10 per cent, of pitch was
thoroughly blended with the culm. From the mixer this compost
was conveyed to a cylindrical drier and thence to the briqueting
press which made briquets 4 in. X 4 in X 9 in. When thoroughly
dried, these were tested in the small locomotives at the mines,
but did not prove successful. It was concluded that the briquets
were too large and smaller sizes were made, but these, also, on
trial, were not considered a success. The plant was therefore
abandoned. After being out of use a year or more, Mr. Thomas
A. Edison came to Audenreid and looked over the plant and pur-
chased it. He removed it to his magnetic iron-ore plant in New
Jersey, where it was used in making briquets from the magnetic
iron-ore dust, until the whole plant was abandoned.

Next to the anthracite culm waste, the waste of breeze at
the several coke works offers very desirable material for the manu-
facture of briquets. About 2 to 3 per cent, of breeze is made in
the manufacture of coke. As the United States produced, in the
year 1902, 23,090,342 net tons of coke, the amount of breeze at
the low estimate of 2 per cent, would be 461,806 net tons of clean
coke dust for briqueting. All or nearly all of this is at present
wasted. It is quite probable that this coke breeze could be
secured for the removing of it from the coke works, or at most
at a mere nominal price. Briquets could therefore be made at
a moderate cost. Briquets made from anthracite culm and coke
breeze would be very nearly smokeless, the only smoke-producing
substance being the pitch used in bonding these materials.

Much of the great lignite deposits of the United States could
be manufactured into briquets with a minimum percentage of
the binding materials. This would compact this fuel and render
its handling and use quite acceptable.

In connection with fuel briqueting in the United States,
Consul-General Frank H. Mason, of Berlin, Germany, under date
of November 20, 1902, reported as follows: "The correspondence
received during the past month from nearly every state and

464 TREATISE ON COKE

territory of the Union, making inquiry concerning the machinery
and processes employed in Germany for making fuel briquets
from lignite, peat, and coal dust, indicates that public interest in
the whole subject of utilizing the hitherto wasted or neglected fuel
materials, so abundant in America, has been thoroughly aroused.

"There are in New England, Western New York, Michigan,
Illinois, Wisconsin, Oregon, Washington, the two Dakotas, and
the Gulf States, large deposits of lignite and material midway
in character between lignite and peat, and there are in all the
coal-mining states enormous quantities of bituminous dust and
anthracite culm, all of which may, by the employment of modern
machinery and processes, be added to the fuel supply of the
United States." This is an industry in which the first tentative
efforts made in the United States have generally failed, but which
has been developed in European countries into an important and
successful system of production.

Samples of lignite from near Bismark, North Dakota, and
from Troy, Alabama, have been received at the German Consulate,
turned over to a German briqueting syndicate, and molded
experimentally into briquets with entire success. The Dakota
lignite is old and hard, containing 38 per cent, cf water, but
crushes and pulverizes easily and forms, without binder, briquets
of firm structure that burn readily, are practically smokeless,
and leave only 4 per cent, of ash, while the best German brown-
coal briquets yield from 9 to 12 per cent, of inorganic residue.
The percentage of water contained is rather low, but by adapting
the heating and drying process to that proportion of moisture,
this obstacle, such as it is, can be easily met, and the reduced
task of evaporation will be an economy in the general process.
The Alabama lignite, on the other hand, is an ideal material,
and from the one sample submitted, it is conceded in Germany
to be even superior to the standard brown coals of Germany.
It contains the direct percentage of moisture, crushes easily, and
molds readily into firm, shining, black briquets. The importance
of these simple demonstrations will be inferred from the fact that,
according to a recent State geological report, there are 55,000
square miles of lignite beds in the Dakotas and Montana, all near
the surface of the ground, and ranging in depth from 20 to 80
feet. The extent of the lignite deposits in the Gulf States is
perhaps less exactly known, but they certainly cover a large area.

When, some 10 years ago, the attention of American iron
makers was called to the German system of making blast-furnace
coke in retort ovens, which save the valuable volatile elements
of the coal, it was thought worth while by certain of them to
bring over two carloads of Connellsville coal to be coked as a test
by the German process. The complete success of that experi-
ment decided the introduction of the standard German type of
coking ovens in the United States.

TREATISE ON COKE 465

Something similar, it would seem, might profitably be done
with the materials that Americans have not yet succeeded in
converting into satisfactory briquets. There are experienced
engineers and a dozen manufacturers of briquet-making machinery
who would gladly cooperate in these tests and would furnish
machinery adapted to working the material thus technically
defined. Upon a basis of such tests, plans and estimates could
be obtained for the erection of plants in the United States with
specified daily capacity.

As a result of the present widespread interest in this subject
and the many inquiries that have been received from mine owners
and operators for technical information as to processes, cost and
capacity of machinery, etc., a combination has been formed
between three of the foremost machine builders in Germany,
whose products collectively include all the necessary apparatus for
making briquets from coal dust, brown coal, and peat. The
purpose of this syndicate is to meet promptly and efficiently
the American demand for machinery and working methods,
which represent the best results obtained by scientific study and
mature experience in Germany. The combination is entitled "The
Export Syndicate of Briquet Machinery Manufacturers," with
central office at No. 59 Friedrich Strasse, Berlin, and includes
as members the Zeiter Eisengiesserei, at Zeitz, Saxony, the
Maschinenfabrik Buckau, at Magdeburg, and the Maschinenfabrik,
at Ehrenfeld, Cologne.

An opportunity will be thus offered for American mine owners
and operators to ascertain definitely in advance the theoretical
value of their materials for briquet making and the cost of a plant
of a given daily capacity.

Meanwhile the same results can be reached with important
saving of time if owners of coal mines or lignite beds will send
to the above address, directly or through the Berlin consulate,
10-pound samples of their material in the exact condition in which
it will be available in large quantities for practical use. The
percentage of water in any briquet material is an important factor
in determining how it best can be worked.

If the material is dry — as, for instance, slack from a well-
drained bituminous coal mine — the sample may be sent in an
ordinary box or package. If, on the other hand, the slack or
culm is obtained wet from a washing process, or if the material
is lignite or peat from a bog, the sample should be sent in a tight
tin case, which will preserve the exact percentage of moisture that
will be encountered when it is mined for use on an industrial scale.

The postal-package treaty between the United States and
Germany provides for the transmission, by post, reciprocally, of
packages not exceeding 5 kilograms (about 11 pounds avoir-
dupois) in weight at a uniform rate of 12 cents per pound. Allow-
ing for the weight of the necessary covering, this will enable

466 TREATISE ON COKE

interested persons in America to forward to Berlin samples of
their material sufficient in quantity to be analyzed, submitted to
various tests, and even made experimentally into briquets, so that
its adaptability to briquet manufacture, the percentage of binder
required, the calorific value of the product, and methods and
.machinery best adapted to working it can be ascertained and
reported on in advance by responsible experts, who are prepared
to follow up their estimates by practical operations. In this way
the technical experience and scientific knowledge that have made
the briquet industry successful and important in Germany will
be made directly available by American operators, who desire to
begin at the point of economic efficiency that has been attained
by the best practice in Europe.

In addition to the utilization of coal and coke wastes and
lignite for the manufacture of briquets, there are, in the United
States, large areas of bogs in the West, North, and Northeast
that could be used in the production of briquets. Some of these
bogs are accumulating at this time, especially in the North, where
frequent rains occur. The whole operation of the growth of these
bogs can be witnessed in Newfoundland, where the vegetable
matter receives frequent drizzling rains, rotting the thick surface
of the mosses and converting them into the black matter called peat.

Consul-General Mason reported the following in regard to peat
in the latter part of 1903:

"There are in New England and in the Middle and Western
States vast beds of peat that have been heretofore left neglected
as waste material in the economy of nature. In Alaska and on
the islands that lie along its shores — where the limited supply of
coal brought from British Columbia sells for $20 per ton and men
perish from cold for want of fuel — there is a practically unlimited
supply of peat of the best quality, all of which would be available
as fuel if carbonized and converted into coal or briquets. No
process that includes air drying or works the peat at ordinary
temperatures would be practicable there for more than a small part
of each year — the brief arctic summer of that northern clime. If
those vast deposits of fuel material are ever successfully utilized,
it must be by some process similar to those herein described,
whereby the peat is quickly machine-dried by means independent
of the sun or wind and then carbonized by heat that can defy
even the cold of an arctic winter. The electrical method will be
first tried on an industrial scale in Ireland, an island which, with
a total area of 32,393 square miles, has 2,830,000 acres of peat."

Dr. Edward Atkinson, president of the Boston Manufacturers'
Insurance Company, has issued a pamphlet bearing on the briquet-
ing of bog materials, and dated March, 1903. He says: "Consul-
General Mason's reports give minute accounts with diagrams and
descriptions of the machinery used. I observe, however, that
the mechanism described is almost identical with the mechanism

TREATISE ON COKE 467

that I invented in 1867 for converting peat into briquets at the
Indian Orchard Mills. The price of coal in that paper-money
era being very high, we successfully worked a peat bog for many
months in a boiler plant of mills of about 30,000 spindles, giving
it up when coal went back to normal prices. But what we call
peat, which is very full of hqllow fibers of the grasses that grow
on the top of the moss preserved in the peat, is very much more
difficult to compress, and takes much longer to dry than this slimy,
nearly homogeneous black mud from the Taunton River. Pro-
fessor Norton is now having a machine made on my original plan
for the conversion of this mud into briquets.

"The only claim that I make is to having called attention to
what seems to me a great fact, namely, that the mud in the fresh
and salt water meadows, as well as the peat in the peat bogs, may
be regarded as a vast source of energy, requiring for its conversion
into heat mechanical appliances rather than any other, so as to
bring these materials into a semisolid shape, in which they may
be converted into heat and power."

The Peat Fuel Company of America bought out a small estab-
lishment in New Haven, Connecticut, where coke was made for
several years from salt-marsh mud taken from the sides of a tidal
creek. This product has been made in a small way and sold in
New Haven at full prices. The promoters have now moved the
apparatus to a grass meadow and are opening bogs in Brookfield,
Massachusetts, where the mud appears to be composed almost
wholly of decayed grasses. The areas in this section are very
large. This Brookfield bog, it is stated, has been sounded to a
depth of 47 feet without reaching bottom. Fourteen hundred
pounds, net weight, as taken from the bottom of a trial pit, yielded
800 pounds of fuel, bone dry. It is expected that this deposit
will yield 500 tons of coke, or 1,000 tons of fuel briquets per acre,
for each foot in depth below the sod. This mud is to be artificially
dried, molded into hollow cylinders, and made in coke of first
quality.

It is said that great deposits of mud are known to exist all
over the United States: in the northern section, in the hollows
of the glacial drift; in the West, in the swamp lands and in the
sloughs or hollows of the prairies; in the South, in the hollows
left by the great lagoons that covered an immense area when the
waters of the Gulf of Mexico receded, and the lowlands or prai-
ries of Texas, Louisiana, and all the other states up to the Ohio
River, were slowly lifted above the sea level; and in the savannas
and swamps of the eastern coast.

Messrs. Chisholm, Boyd, & Co., of Chicago, have given briquet-
ing machinery considerable practical attention ; but so far mainly
in the interest of blast-furnace work in briqueting the iron-ore
dust from the down-comer pipe. The bonding material in this
operation is lime. The iron-ore dust with 1 to 2 per cent, of

468

TREATISE ON COKE

slacked lime (cream of lime) is thoroughly mixed and wetted into
a pasty condition in a large cylinder mixer annex a, Fig. 31, to
the briqueting machine. This prepared paste is passed into a
large pan in which are heavy traversing rollers b immediately
over a circular steel disk c perforated around its outward per-
imeter; the heavy rollers press the prepared material into these
perforations in the circular movement of the disk. An arm d
with two punchers removes the briquets from the large disk and
delivers them on a conveyer e that carries them to any desired
point, where they can be dried for use. It may be noted here
that this briqueting machine is not confined to the treatment of

FIG. 31

iron-ore dust, but can be used in briqueting any materials that
can be prepared for this purpose.

The Henry S. Mould Company,' of Pittsburg, Pennsylvania, is
now making and testing briqueting machinery. The following
description, with Fig. 32, shows the general plan of the White
coal briqueting press and apparatus in which melted pitch is
used as a binder. The process is shown commencing with fine coal
in condition for briqueting. Where it is necessary to crush or
screen the coal to bring it down to the proper size, this oper-
ation is done first and requires the proper crushing and screening
apparatus.

The fine coal is automatically fed to the heater. This heater
is built in several styles, some using steam, others using direct
or indirect heat as best adapted to the coal to be operated upon.

470 TREATISE ON COKE

The object of the heater is to eliminate all moisture and bring
the temperature of the coal up to about 300° F. It is desirable
to have the material at this temperature so that it will not chill
and thicken the pitch when introduced into the coal, but become
a plastic mass when properly mixed. From the heater, the fine
coal is deposited at the end of the conveying mixer o. On a
floor slightly elevated are two pitch tanks m, having steam pipes
on the sides and bottom, the first one to melt the solid pitch and
the second to keep the pitch in a melted condition for use. An
automatic measuring device distributes the pitch in the proper
proportion to the coal in the mixer. The mass is thoroughly
mixed and conveyed from the mixer to hopper d of the press by
feed-belt 5. The briquets i are ejected on a carrier belt e, and
with slight cooling are ready for storage bins or cars.

The pressing mechanism is very simple. A rotating crank a
and pitman b move the compression plungers forwards and back-
wards with a movement exactly the same as that of the piston
rod of an engine. The press box c has an independent motion,
as it is operated by the cam-track in the gear through the cam-
arm, rocker-arm, and links. The press box remains stationary
at its rearward position, while the compression plungers pass
across its interior space, pushing the material ahead of them and
forcing it into the molds. This motion continues until the plun-
gers have entered the mold a sufficient distance to compact the
material into solid briquets under great pressure. The continued
motion of the crank will now start the compression plungers for-
wards. At the same instant, the cam in the main gear causes the
press box to move forwards at first with a motion exactly coin-
ciding with that of the compression plungers, then with an increas-
ing speed forwards, thus gaining on the receding compression
plungers until their ends project slightly through the back ends
of the molds. This motion ejects the briquets; and should they
stick to the plungers, they are displaced by the knocking-off device
and fall upon the delivery belt. The cam-track now returns the
press box quickly to its normal, or rearward, position. The com-
pression plungers at this time being at their forward position,
new material falls into the press box ready for another compression.
The motion of the press box in relation to the hopper above is
such that it crowds the material downwards when moving rear-
wards. Hanging bars also swing through the material, breaking
down any arch that may have formed over the plungers. An
adjustment is provided whereby the compression plungers may
enter any desired distance into the molds.

The entire operation is controlled by the press operator, one
lever controlling the friction clutch pulley on the mixer, this latter
lever also controlling the heater and pitch feed. For a single-
press plant, besides the press operator, two men are required to
take care of the pitch tanks and heater, and this is all the labor

TREATISE ON COKE 471

required from the point at which the fine coal is fed to the heater
to the finished briquet on the carrier belt. In the double-press
plant, the presses are built right- and left-handed, so that one
operator can take care of both presses. The pitch tanks are
enlarged so as to have capacity for both presses, and, where desired,
a single heater of sufficient capacity will supply both presses.
An additional man is required for the two-press plant. The pres-
sure on the White briqueting press is adjustable, and from a light
pressure to 20,000 pounds per square inch can be put upon the
briquets. It is said that by means of heavy pressure it is possible
to successfully briquet bituminous coals with from 4 to 5 per cent,
of pitch, whereas from 7 to 12 per cent, is the best done in foreign
practice.

The capacity of the press and size of the heater depend on
the size of the briquets made. Four shapes of briquets can be
made on the White press; and these presses vary in capacity from
50 to 120 tons per day of 10 hours.

Another method of operation, known as the dry process, is
where the pitch is broken up fine and mixed with the coal, the
mass put through a disintegrator, then through a heater, and
finally to the briqueting press.

The price of the No. 1 White briqueting press complete is
$6,000, but it is difficult to give anything like accurate figures on
a complete plant without knowing the binder or process to be used.
The necessary apparatus outside of power and buildings, etc.,
for a plant to produce 12 tons per hour, would be from $35,000
to $40,000.

There are a number of binders that can be used in the pro-
duction of coke briquets, some of which are secret mixtures and
some patented. These binders vary in their effectiveness and
also in their cost, ranging from 40 cents to $1 per ton of briquets.
In a good-sized plant, the total operating cost should not exceed
10 to 12^ cents per ton of briquets.

During a recent visit to portions of Europe, Asia, and Africa,
I noticed great heaps of briqueted fuel stored along the lines of
railroads in these countries. It is used in Palestine on the rail-
road from the seaport of Jaffa to the city of Jerusalem, and in
Egypt on the railway from Alexandria to Cario. In Continental
Europe, it is freely used on most of the railroads, especially in
Germany, Belgium, and France. It is also coming into use, in
a moderate way, in the British Isles. The use of the briqueted
fuel in generating steam in the locomotives appeared to afford
ample power in the passenger-train service, but these, as a general
condition, were quite short and light as compared with the long
and heavy passenger trains in the United States.

In Ulster, Ireland, I was favored with briquet fuel in a small
grate in my room. At this hotel, it was mixed with a small por-
tion of coal. The heat derived from the briquets did not impress

472

TREATISE ON COKE

i it

TREATISE ON COKE 473

me with a feeling of great warmth; just the opposite, and the
smoke from the pitchy bonding material emitted fumes that were
not at all pleasant. At this place, semi -bituminous coal for domes-
tic uses cost $6 per ton, so that the utilization of the slack coal
into briquets was a matter of economic necessity.

In conclusion, the following extract is given from a report on
the production of coal in 1902, by Mr. E. W. Parker:

Prior to 1902, about 400 patents had been issued in the United
States on artificial fuels, but up to the close of 1901 none had
proved a commercial success. Mr. Parker gives a list of United
States patents granted since January 1, 1902. It remains to be
seen whether any of them will be successfully developed. The
list includes 37 patents, but contains no mention of fuels made
from petroleum or petroleum residue unless used in connection
with coal, lignite, or peat. Neither does it include any compounds
that have for their object the increase of fuel efficiency unless
they are used in the manufacture of the fuel itself. Three patents
were issued on briqueting machinery.

The steady advance in the price of coal — no less than 40 per
cent. — which has taken place since 1808 has stimulated experi-
ments looking to the invention of artificial fuels. Results obtained
in foreign countries from the use of lignite and peat in briqueted
form should encourage producers in the United States to try
similar methods of manufacture. Small sizes of anthracite for-
merly wasted are indeed recovered now by washeries from the
old culm banks and utilized.. A large amount of coal lost in the
form of dust or finely pulverized material might also be put into
convenient shape for domestic consumption, and slack now wasted
at many of the bituminous mines in the United States might be
used to advantage if compressed into briquets. There are many
indications that the time is not far distant when these neglected
fuel resources will be utilized.

' THIRD REPORT OF PROF. CHARLES L. NORTON
UPON BOG FUEL

Since making the earlier report on the bog fuel, several new
phases of the matter have developed. We have perfected our
Atkinson-Norton machine and have manufactured or, as they say
abroad, "machined" a great amount of peat in large and small
lots. The details of the machine are shown in Fig. 33.

With the examination of the fuels brought to us to run through
this machine we have found a number of interesting developments.

1. All the bog fuel appears to be capable of treating by macer-
ation in this machine so as to develop a binder that causes the
blocks of soft mud-like material to become, in drying, of about
the densitv and hardness of hard wood.

474 TREATISE ON COKE

2. The by-products appear to be much like the by-products
of the European bog matter.

3. No satisfactory coke can be made without macerating and
drying before coking, and even then the coke resembles charcoal,
unless coked under pressure.

4. Many bog samples have been found that contain too great
an amount of ash to be of commercial value.

5. Some of the best samples contain as large a percentage of
volatile matter as 65 to 70 per cent., making them apparently of
great value as producers of gas.

The machine, as will be seen from the drawings, Fig. 33, is
much like the Swedish and German machines, and consists of a
set of revolving blades and cutters incased in a closely fitting
cylinder, together with a pair of Archimedean screws to force the
bog matter on to the cutters and out through a conical nozzle.
The whole arrangement is not unlike the ordinary sausage machine.
There appears to be a certain ratio of cutting to grinding and
squeezing, which gives the most dense and best drying blocks,
and the success of any machine must depend in large part on its
adaptability to the particular bog matter with which it is used.
Those machines that are best suited to a peat full of roots and
sticks are less suited for use with some of the softer and less fibrous
masses. By varying the number of cutters and the relative posi-
tions of the forcing screws, the Atkinson-Norton machine is adapt-
able to a wide variety of peats and hence is useful in examining
samples from different sources.

The machine is simple in operation, the fuel being dumped into
the hopper, rammed down from time to time, and the finished prod-
uct coming out in a continuous stream from the nozzle, is cut into
blocks and dried on boards. In actual commercial practice, both
the cutting and removing from the nozzle can be done mechan-
ically. Until the machine is set up and run on the bog for some
time, there is no way of estimating its output very closely, but it
is probable that from 5 to 10 tons a day, dry fuel, can be got
from the machine with a 2-horsepower motor.

The bog fuel, on coming from the machine, may be air-dried
under ordinary conditions in from 2 to 6 weeks, and by supplying
artificial heat in a much shorter time. The danger of cracking in
drying may be diminished by regrinding through the machine
from time to time a few bits of already dried peat along with the
fresh charge of wet material. After thorough drying, the blocks
are sensibly waterproof and they may be left outdoors without
injury.

The bog matter that makes the densest blocks of the highest
calorific power is usually of a brown color rather than a black,
and it may or may not be fibrous. As has been predicted by
several writers, the material highest in ash comes from the lower
parts of those bogs that are the settling basins for rivers and

TREATISE ON COKE 475

smaller streams on considerably higher land and occasionally
overflowing into the bogs.

To be of maximum fuel value, a bog should yield a fuel of
high calorific power, have a small percentage of ash, and should
dry to a low percentage of water. Yet perhaps more important
is it that the bog should be capable of being drained, and of such
depth as to make it worth while to erect a plant of considerable
size, since it is apparent that larger plants will be relatively more
economical. The small bog can only pay as a supply of "machined"
fuel for a local market fairly remote from the coal fields, but that
they have a future in that direction is my firm belief.

The direction in which we must look for the greatest develop-
ment of bog fuel is in the matter of gas production. While we
do not yet know fully the exact nature of or amount of gas from
a very large number of American bogs; it is clear that gas in approx-
imately the same amounts and of much the same kind as that got
from soft coal can be produced from some of the New England
peats. The gas is nearly free from sulphur, has a fair amount of
illuminants, and unless it proves to contain too much carbon-
dioxide is of great value for heat, light, and power purposes.
We shall very shortly have some further demonstrations of the
use of peat gas in large gas engines.

The matter of by-products has been given a great deal of
attention by us, but it is of such a delicate chemical nature that
we are still far from, having at hand a list of all the by-products
in measured amounts obtained from the peat and bog fuels.

There is evidently a considerable difference in the by-products
of material from different bogs, among the most common, beside
coke and gas, being ammonia, acetic acid, anthracene, creosote,
carbolic acid, toluene, phenol, and pitch. The by-products of
the material taken from the Taunton bog were found to be as
follows: (1) tar containing carbolic acid, toluene, phenol, benzol,
creosote, and anthracene, together with a residue of black pitch;
(2) tar water containing ammonium sulphate, alcohol, and acetic
acid; (3) gas, whose volume was approximately 4 cubic feet per
pound of peat, and whose calorific power was about 654 British
thermal units per cubic foot. Coal would yield perhaps 5 cubic
feet of gas of the same heating power. The peat gas is richer in
illuminants.

We are preparing to make an exhaustive examination on large
samples, to determine as nearly as may be the money value of
the total by-products.

During the summer, an unusual number of distinguished Euro-
pean scientists and engineers have visited the Institute on their
way to or from St. Louis, and many have called attention to
the less fibrous or woody conditions of the bog fuel we are using
as compared with that with which they were familiar abroad.
It may be that there is a difference in the final condition of the

476 TREATISE ON COKE

decayed hydrocarbon masses that will account for the great
amount of volatile gas-producing matter in some of our peats,
that is, 65 to 70 per cent., as compared with 40 per cent, for many
European peats, and 35 per cent, for coal. Of course, these gas-
eous bogs contain very little fixed carbon.

Respectfully submitted,

CHARLES L. NORTON.
MASSACHUSETTS INSTITUTE OP

TECHNOLOGY,

BOSTON, MASS., U. S. A.

December, 1904.

I NDEX

Acetic acid, Effect of, in removing sulphur,

40.

Adelaide coke, 282.

Advantages of different coal fields for loca-
tion of coke plants, 396.
Alabama coal and coke, Analyses of, 120.

Stewart washery in, 114.

Washery at Brookwood, 75.
Alaska coal, Analysis of, 29.
Alleghany Mountain coke, 162.
American Coke Company's plant, 375.
Ammonia plant, 323.

Yield of, 257.

Ammonium sulphate, Costs of manufacture,
403.

sulphate, Market for, 401.
Analyses and coking qualities of Rocky
Mountain coals, 10, 17.

of Alabama coal and coke, 120.

of Alaska coal, 29.

of anthracite, 7.

of Appalachian bituminous coals, 8.

of Appalachian coking coals, 25.

of British Columbia and Vancouver coals,
17.

of brown coals of Texas, 12.

of Central Field coals, 9.

of Coahuila Coal Company's coal and coke,
18.

of coal before and after washing. Table of,
113.

of coal, washed coal, coke, and refuse, 98.

of Connellsville coal and coke, 147.

of Connellsville coke from beehive and
Semet-Solvay ovens, 280.

of Davis coal and coke, 270.

of different gases, Table of, 246.

of fuels, Table of, 37.

of German coking coals, Table of, 33.

of Illinois coal and coke, 186.

of Kanawha Valley coal and coke, 147.

of Michigan coals, 9.

of Morris Run coal, 266.

of Nova Scotia and New Brunswick coal,
16.

of Pacific coast coal, 16.,

Analyses of Rocky Mountain and Great Plains
coal field, 17.

of the several varieties of coals in the
Pacific Coast coal fields, 13.

of Thomas coal and coke, 271.

of Triassic coals and cokes, 7.

of Tuscarawas coal and coke, 335.

of Welsh coal, Table of, 34.

of Western coals, 12.

of Westphalian coking coal, 244.

Relation of, to coking properties, 31.
Anthracite, 21.

Analyses of, 7.

,Compressive strength of, 360.

fields, 5.

fields, Structure of, 8.

in blast furnace, 326, 354.

necessary to make one ton of pig iron, 338.

Physical properties of, 326.

screenings, Briquets from, 410.'
Appalachian bituminous coals, Analyses of, 8.

coal field, 7.
Appolt coke oven, 212.

coke ovens at Blanzy, 215.
Ash. Analyses of, 98.
Atkinson- Norton briquet machine, 473.
Atlantic Coast Triassic coal fields, 7.
Austria-Hungary, Briqueting in, 417.
Axioms, 199.

Bauer by-product coke ovens, 302.
Baum washer, 123.

washing plant at Gladbeck, Westphalia.

128.

Beaverton, Peat plant at, 456.
Beehive and by-product coke, Comparison of,
326.

and Semet-Solvay coke plants, Relative
costs and economies, 284.

by-product oven, 311.

coke oven, 148.

coke oven, construction of, Specifications
for, 153.

coke oven, Cost of making coke in, 346.

coke oven, Yield from, 163.

coke, Structure of, 282.
Belgian coke oven, 206.

XVI

INDEX

Belgium, Briqueting in, 419.

Cost of briqueting in, 422.

Price of briquets in, 419.
Belt Mountain coals, 29.
Bennington, Belgium coke ovens at, 208.
Benzol, 404.

plant, 325.

Berard's coal-washing machine, 63.
Bernard coke oven, 294, 379.
Bessemer metal, Coke required to smelt, 343.
Bk'trix briquet press, 427.
Binders for briquets, 413.
Bituminization of coal westward, 23.
Bituminous coal, 21.

coals, Analyses of Appalachian, 8.
Blanzy, Appolt coke ovens at, 215.
Blast furnace charges in coke tests, 285.

furnace experiments, Semet-Solvay coke,
277.

furnace fuels, from 1854 to 1902, Table of,
326.

furnaces, comparative work of fuels in,
Table of, 354.

furnace tests, Table of results, 287.
Bog fuel, Report of Prof. Chas. L. Norton, 473.
Bourne?, briquet press, 432.
Bradford coal breaker, 47.
Briquet binders, 413.

factory at Lauchhammer, 437.

fuel in Ireland, 471.

machine, Atkinson- Norton, 473.

machine, Bictrix, 427.

machine, Bourriez, 432.

machine, Chisholm, Boyd & Co., 467.

machine, Dickson, 458.

machine, Dobson 459.

machine, Dupuy, 429.

machine, Henry S. Mould Company, 468.

machine, Johnson, 449.

machine, Wiesner, 418.

machine, Zeitz, 437.

machinery manufacturers, The German
export syndicate of, 465.

machines used in Saxony, 437.

material. Samples for testing, 465.

presses, 414.

press for egg-shaped fuel, 429.
Briqxieting, 406.

cost of, in Belgium, 422.

in Austria- Hungary, 417.

in Belgium, 419.

in Canada, 453.

in France, 422.

in Germany, 433.

in Great Britain, 448.

in Norway and Sweden, 445.

in the United States, 462.

in Wales, 449.
Briquets, Anthracite, 410.

Carboniferous mud, 412.

Briquets, Characteristics of. 407.

Charcoal, 411, 418.

Coal-slack, 409.

Coke-breeze, 410.

coke, Cost of plant for, 430.

Cost of, in Canada, 462

Cost of, in Germany, 439.

Heating value of, 419.

Lignite, 411, 464.

Loss in handling, 409.

Methods and costs of manufacturing, 417.

Mud, 467.

Peat, 411.

Petroleum, 413, 431.

Production of, in Germany, 434.

Sawdust, 439.

Sizes and shapes of, 407.

Standard sizes of, in France, 424.

Weight per cubic foot of, 409.

Welsh, Breakage in handling, 453.
British Columbia coal fields, 17.

Columbia coals, Analyses of, 17.
Brookwood, Alabama, washery, 75.
Brown coals of Texas, Analyses of, 12.
Browney coke plant, 167.
Brunck coke ovens, 298.

By-product apparatus at Mines of Campagnac,
229.

apparatus at Otto Station, 249.

apparatus, Cost of, 243.

apparatus for Otto-Hoffman ovens, 239.

apparatus, Schniewind, 254.

coke-making statistics, 134.

coke ovens by States, 135.

coke oyens in the United States and Canada
in 1903, 400.

ovens in the United States, Table of, 205.
By-products, Advisability of saving, 401.

and coke, Yield of, 258.

from Daube's coke oven, 177.

from Siebel ovens, 224.

of the coke industry, 256.

Plant for saving, 320.

Value of, 243.

Value of, per ton of coke. Table, 398.

Yield of, from Morris Run coal, 266, 269.

Calorific values of fuels. Laboratory methods

of determining, 353.
Cambria, Cost of coke at, 339, 340.
Canada, Briqueting in, 452.

Coal fields of, 16.
Capacity of jigs, 95.

of revolving screens, 93.
Carboniferous mud briquets, 412.
Carbonization, Rate of, 192.
Carnap, Germany, Coal distillation plant at,

320.
Cell space in coke, 330, 351.

INDEX

xvn

Cell structure, Laboratory tests, 356.
Cellulose, 21.
Central coal field, 9.

Field coals, Analyses of, 9.
Charcoal briquets, 411, 418.

briquets required to make one ton of pig
iron, 338.

in blast furnace, 326, 354.

Physical properties of, 326.
Charging and coke-pushing machinery, 315.
Chemical properties of coal, 19.
Chisholm, Boyd & Co. briquet machine, 467.
Classification and areas of the coal fields of

the United States, 1902, 14.
Coahuila Coal Company's coal and coke,
Analyses of, 18.

Washing plant at, 79.
Coal, Changes during formation of, 21.

consumed in American cities in 1900, 383.

consumed in United Kingdom for 1898, 381.

crushing, 46.

Debituminization of, eastward, Table of, 24.

distillation plant at Matthias Stinnes mine,
Germany, 320.

field, Appalachian, 7.

field, Central, 9.

field, Eastern Rocky Mountain and Great
Plains, 17.

field, Michigan, 9.

field, Northern, 9.

field, Texas, 12.

field, Western, 11.

fields, Adaptability of different types of
ovens, 392.

fields, Anthracite, 5.

fields, Atlantic Coast Triassic, 7.

fields, Mexican, 17.

fields of British Columbia and Vancouver
Island, 17.

fields of Canada, 16.

fields of North America, 1.

fields of Nova Scotia and New Brunswick, 16.

fields of the United States, 5.

fields of the United States for 1902, 14.

fields of the world, 1902, Diagram of, 2.

fields, Pacific Coast, 12.

fields, Qualities of coal and coke from dif-
ferent, 392.

fields, Rocky Mountain, 11.

Formation and chemical properties of, 19.

Importance of, 1.

Impurities in, 38.

periods, 4.

Principal elements of, 22.

ramming machine, 316.

Relations of different varieties, Diagram of,
21.

required to produce one ton of coke. 137,
141.

Results of washing, Table of, 113.

Coal slack briquets, 409.

used in manufacturing coke in the Uni*ed
States, 140.

Varieties of, 22.

washer, Robinson, 99.

washing, 56.

Weight per bushel of, 196.

World's product of, 1901, 1902, Diagram of,

Coals, Analyses and coking qualities of Rocky
Mountain, 10.

Analyses of British Columbia and Van-
couver, 17.

Analyses of Central Field, 9.

Analyses of different varieties, Table.of, 22.

Analyses of Michigan, 9.

Analyses of Nova Scotia and New Bruns-
wick, 16.

Analyses of Pacific Coast, 16.

Analyses of the several varieties of, in th»
Pacific Coast coal fields, 13.

Analyses of Western, 12.

and cokes, Analyses of Triassic, 7.

and impurities, Specific gravities of, 56

Coking and non-coking, Table of, 26.

Coking, Composition of, 24.
Coherence in handling coke, 334.
Coke, Amount of coal vised in manufacture of,
in the United States, 140.

Analyses of Triassic coals and, 7.

Average value of, in United States, 142.

beehive, Structure of, 282.

breeze briquets, 410.

briquets, Cost of plant for, 430.

by-products, Plant for saving, 320.

cell space, 351.

Coal required to produce one ton of, 137,
141.

Coherence in handling, 334.

Compressive strength of, 360.

Cost of, at Glassport, Cambria, and Ger-
many, Table of, 339.

Cost of making, in beehive ovens, 346.

Density of, 351.

drawer, Hebb, 188.

drawer, Smith, 187.

drawer, Thomas, 166.

Effect of type of ovens on physical prop-
erties of, 348.

Effect on, produced by crushing the coal,
195.

exported from the United States, 139.

from compressed fuel, 312.

handling machinery, 315.

Hardness and cell space of, Table of, 330,
332.

imported to the United States, 139.

in blast furnaces, 326, 354.

in blast furnaces, Tests of, 287.

industry, History and development of, 131.

XV111

INDEX

Coke industry, Statistics of, 133.
Kentucky, Pineville, 358.
Laboratory tests of, 355.
larry, Electric, 362.
making for profit, 369.
making in by-product ovens, Statistics

of, 134.
manufacture in the United States, Diagram

showing growth of, 138.
Melting power of, 343.
oven, Appolt, 212.
oven, Bauer, 302.
oven, Beehive, 148.
oven, Belgian, 206.
oven, Bernard, 294.
oven, Brunck, 298.
oven, Continental, 150.
oven, Coppee, 208.
oven, Daube's, 177.
oven, Festner-Hoffman, 260.
oven, Hiissner, 292.
oven, Lowe, 306.
oven, Newcastle-upon-Tyne, 148.
' oven, Old Welsh, 164.
oven, Oliver plant, 150.
oven, Otto beehive by-product, 311.
oven, Otto- Hoffman, 235.
oven, Ramsay, 173.
oven, Rothberg, 290.
oven, Schniewind, 252.
oven, Seibel's, 223,
oven, Semet-Solvay, 263.
oven, Simon-Carves, 219.
oven, statement of Solvay Process Company

for 1894, 268.
oven, Thomas, 164.
oven, Wharton, 152.
ovens, Adaptability of different types of,

to the several coal fields, 392.
ovens at Browney Colliery, 167.
ovens, By-product, by states, 135.
ovens, By-product, in the United States and

Canada in 1903, 400.
ovens, By-product, in the United States,

Table of, 205.

ovens, Comparison of types of, 214.
ovens. Condition of coal charged in the

United States, 141.
ovens, Costs of material for, 176.
ovens, Effects of types of, on physical

properties of coke, 348.
ovens in the United States, 134.
ovens, Newton-Chambers, 186.
ovens, Number of, advisable in plant,

369.
ovens of different types, Relative economy

of, 397.
ovens, Retort and by-product-saving,

Introduction, 200.
Peat, 442.

Coke, physical and chemical properties of,
Table of, 334.

Physical properties of, 326, 329.

plant, Life of, 371.

plant, Locating, 361.

plant location, Comparison of advantages
of different coal fields for, 396.

Preparation of coals for the manufacture of,
43.

produced in the United States, 139.

produced in the United States, Table
of, 136.

pusher, 318.

pushing machinery, 315.

Semet-Solvay, Structure of, 282.

Tests of blast-furnace charges of, 285.

Tests of, with CO2, 359.

to make one ton of pig iron, 338.

to smelt Bessemer metal, Beehive and
Semet-Solvay, 343.

Weight of, 197.

What constitutes pure, 333.

yield of different ovens, 342.

yield, Percentage of, in beehive oven, 158.
Coking and non-coking coals, Table of, 26.

charge, 48- and 72-hour, 158.

coals, Analyses of Appalachian, 25.

coals, Analyses of Durham, 25.

coals, German, Table of, 33.

coals, Influence of composition of, 27.

Connellsville and Tuscarawas coals in Ger-
many, 335.

costs, 175.

experiments and results, 192.

Heminway process of, 178.

in heaps or" mounds, 145.

in Ramsay and beehive ovens, Table of
experiments, 174.

Percentage of sulphur volatilized in, Table
of, 39.

process, The, 157.

properties and fusibility, 31.

properties of different portions of Connells-
ville seam, 198.

Rate of, 192.

tests, 160.

To determine loss of carbon in, 147.
Comparative work of fuels in blast furnaces,

354.

Comparison of beehive and by-product coke,
326.

of beehive and by-product coking, 335.

of different types of coke ovens, 397.

of oven types, 214.
Composition of coking coal, 24.
Compressed fuel, Manufacture of coke from,

312.

Condensation plant at the Julienhutte, 239.
Condensing plant, Schniewind, 254.
Condition of coal charged into coke ovens, 141.

INDEX

xix

Conemaugh furnace, Coppee ovens at, 210.
Connellsville coal and coke, Analyses of, 147,
280.

coal, By-products from, 246.

coal, Coking, in Germany, 335.

coal in Otto-Hoffman ovens, Test of, 245.

coal seam, Coking properties of different
portions of, 198.

coke, Analysis of, 147.

coke from Semet-Solvay ovens, Experi-
ments in blast furnace, 277.

seam, Localities of phosphorus in, Table, 41.
Continental Coke Company beehive oven, 150.
Coppee coke oven, 208.
Coral coke plant, 376.

Cost and production of Otto-Hoffman ovens,
Johnstown, 344.

of Bernard ovens, 298.

of coke at Glassport, Cambria, and Ger-
many, Table of, 339.

of coke in various ovens, Table of, 398.

of coke, Simon-Carves oven, 222.

of Festner-Hoffman ovens, 263.

of making coke in beehive ovens, 175, 346.

of making coke in Bernard ovens, 297.

of Seibel ovens, 232.

of Semet-Solvay plant, 265.

of various ovens, Table of, 398.

of washing coal at Coahuila, 97.

of Wharton coke oven, 154.
Costs and economies of beehive and Semet-
Solvay plants, 284.

of manufacturing ammonium sulphate, 403.

work, and products of several types of coke

ovens, 392.

CO2, Tests of coke with, 359.
Crushing coal, 46.
Culm briquets, 410.

Daube's economic down-draft coke oven, 177-
Debituminization of coals eastward, Table

of, 24.

Density of coke, 351.
Diagram of coal fields of the world in 1902, 2.

of world's product of coal in 1901 and

1902, 3.

Dickson briquet press, 458.
Diescher coal washer, 71.
Dobson's peat-drying machine, 455.

briquet press, 459.
Dowlais, Resttlts of washing at, 105.
Drying machine for peat, 444.
Dunbar, Semet-Solvay plane at, 273.
Dupuy briquet press, The, 429.
Durham coking coals, Analyses of, 25.

Eastern Rocky Mountain and Great Plains

coal fields 17.
Economy of different types of coke ovens, 397.

Edenborn coke plant, 375.

Effects of types .of coke ovens on physical

properties of coke, 348.
Elliott trough washer, 59.
Ernst coke-handling machinery, 315.
Everett coke-oven gas plant, 384.
Exports of coke, 139.

Festner-Hoffman coke oven, 260.

Formation and chemical properties of coal, 19.

France, Briqueting in, 422.

Seibel ovens in, 224.

Standard size of briquets in, 424.
Frick Coke Company No. 3 Plant, 365.
Fuel briqueting industry, 406.

statistics of American cities for 1900, 383.
Fuels, Analyses of, Table, 37.

Blast-furnace, 1854-1902, Table of, 326.

in blast furnaces, Comparative work of,
Table, 354.

Laboratory methods of determining calorific

values of, 353.
Fusibility and coking properties of coals, 31.

Gases, Table of Analyses of, 246.

Use of, for steaming at Pratt Mines, 169.
Gas, Illuminating, from coke ovens, 381.

plant at Everett, 384.

plant, Lowe, 308.
Gelsenkirchen Brunck ovens, 301.
General conclusions on the several types of

coke ovens, 392.
Geological section, 4.
German coking coals, Table of, 33.
Germany, Briqueting in, 432.

Coal distillation plant at Matthias Stinnes
in, 320.

Coking Connellsville and Tuscarawas coals
in, 335.

Cost of coke in, 339.

Production of briquets in, 434.
Gladbeck, Baum washery at, 128.
Glassport, Cost of coke at, 339.
Graphite, 21.

Great Britain, Briqueting in, 448.
Great Plains coal field, 17.
Greensburg, Stein & Boericke washery at, 122.

Hartz jig, 62.

Heating value of briquets, 419.

Hebb coke drawer, The, 188.

Heminway process of coking, 178.

History and development of the coke industry,

131.

Horsepower required in washery, 91.
Hostetter-Connellsville Coke Company, plant,

375

INDEX

Hiissner coke oven, 292.

coke oven, Coking tests in, 335.
Hydrogen to carbon in various coals, Pro-
portion of, 35.

Illinois coal and coke, Analyses of, 186.

Illuminating gas from coke ovens, 381.

Importance of coal, 1.

Imports of coke, 139.

Improvement of coal effected by washing, 97.

Impurities in coal, 38.

in coke, Effect of, on pig iron, 42.
Ireland, Briquet fuel in, 471.
Iron, Fuel required to make one ton of, 338.

Jamison Coal and Coke Con.pany washery,

122.

Jigs, Capacity of, 95.
Hartz, 62.
Luhrig, 62.
Principle of, 51.
Speed and stroke of, 95.
Stein, 69.
Johnson briquet press, 449.

Company, Blast-furnace experiments with

Semet-Solvay coke by, 277.
Jones & Laughlin Steel Co., Lowe gas plant,

310.
Julienhutte, Plant at, 241.

Kanawha Valley coal and coke, Analyses

of, 147.
Keighley, Fred C. (Paper), 369.

Laboratory methods of determining relative
calorific values of fuel, 353.

tests of coke, 355.
Lacka wanna Iron and Steel Company's plant

at Lebanon, 292, 315.
Larry, 362.

Latrobe coking plant, 186.
Lebanon, Lackawanna Iron and Steel Com-
pany's plant at, 292, 315.
Life of coke plant, 371.
Lignite briquets, 411.

briquets, Cost of, 439.

briquets in the United States, 464.
Lignites, 21.
Link-belt coal breaker, 54.

belt crusher, 55.
Lippincott coke plant, 375.
Locating coke plants, 361.
Lorain, Blast-furnace experiments with

Semet-Solvay coke at, 277.
Loss of carbon in process of coking, 147.
Lowe coke oven, 306.
Luhrig jig, 62.

Luhrig washer at Dowlais, Wales, 101.
washer at Nelsonville, Ohio, 108.
washer at Punxsutawney, 110.

Manufacture of coke, 145.

of coke from compressed fuel, 312.

of sulphate of ammonia, 232.
Map of coal fields of the United States, 6.
Market for tar and ammonium sulphate, 401.
Melting power of coke, 343.
Methods and cost of manufacturing briquets,
417.

of coking coal, 145.
Mexican coal fields, 17.
Mexico, Washing plant at Coahuila, 79.
Michigan coal field, 9.
Mines of Campagnac, By-product coke ovens

at, 224.

Minister Stein pit, Brunck ovens, 301.
Montana coals, Coking, 29.
Morrell coke plant, 364.

Morris Run coal and coke, Analyses of, 266.
Mould Company, Henry S.y briquet machine,

468.
Mud briquets, 467.

Nelsonville, Ohio, Luhrig washer at, 108.
New Brunswick coal fields, 16.

Brunswick coals, Analyses of, 16.

Glasgow Iron, Coal, and Railway Com-
pany, Bernard ovens of, 294.

Glasgow Iron, Coal, and Railway Com-
pany washery, 69.

Newton-Chambers system of coking, 186.
Northern coal field, 9.
Norway, Briqueting in, 445.
Nova Scotia, Bernard ovens in, 294.

Scotia, coal, Analyses of, 16.

Scotia coal fields, 16.

Scotia, Washery of New Glasgow Iron,

Coal, and Railway Company in, 69.
No. 3 Plant, H. C. Frick Coke Company, 365.

Old Welsh oven, 164.
Oliver coke plant, 366.

plant, Beehive oven at, 150.
Otto beehive by-product oven, 311.

Hoffman oven, 235.

Hoffman oven, Coking tests in, 336.

Hoffman oven, Cost of, 243.

Hoffman oven, Temperatures in, 241.

Hoffman ovens and by-product apparatus
at Otto Station, 248.

Hoffman ovens at Everett, Mass., 384.

Hoffman ovens at Johnstown, Costs and
production of, 344.

INDEX

xxi

Pacific Coast coal, Analyses of, 16.

coal fields, Analyses of the coals in, 13.
Peat, 21.

briquets, By-products, 444.
briquets, Cost in Canada, 462.
briquets, Cost in Sweden, 447.
briquets in Canada, 454.
briquets in Germany, Cost of, 442.
coke, 442.
digger, 456.
drying machine, 444.
fuel, 439.

harvesting in Canada, 455.
manufacturing machine, Schlickeysen, 441.
or turf briquets, 411.
plant at Beaverton, 456.
plant at Welland, 455.
Percentage of coke yield from beehive oven,

163.

Petroleum briquets, 413, 431.
Phosphorus in Connellsville seam, Table of, 41.
Percentages of, in Pennsylvania coal and

coke, Table, 41.
Physical and chemical properties of coke,

Table. 334.
properties of charcoal, anthracite, and coke,

326.
properties of coke, Effect of type of ovens

on, 348.
properties of coke, Effects produced on, by

crushing the coal, 195.

Pig iron, Effect of impurities in coke on, 42.
iron, Fuel required to make one ton of, 338.
Pineville coke tests, 358.
Pittsburg Gas and Coke Company plant at

Otto Station, 248.
Pratt Mines, Using waste gases under boilers

at, 169.
Preparation of coals for the manufacture of

coke, 43.

Presses, Closed-mold, 415.
for briquets, 414.
Open-mold, 414.
Prices of coke, 139, 142.

Production of coke, Rank of States and Ter-
ritories in the, 143.
Properties of coke, 329.
Proportion of hydrogen to carbon in various

coals, 35.

Punxsutawney, Liihrig washer at, 110.
Purity of coke, 333.

Ramsay patent beehive coke oven, 173.
Rank of States and Territories in the produc-
tion of coke, 143.
Rate of carbonization, 192.
Rate of coking, 159, 161.

Results with Stewart washery, Table of, 116,
120.

Retort and by-product-saving coke ovens, 200.

oven plant, Location of, 379.
Robinson coal-washer plant, 99.

washer, results, Table of, 100.
Rocky Mountain coal fields, 11.

Mountain coals, Analyses and coking quali-
ties of, 10, 17.
Rothberg by-product coke oven, The, 290.

coke-handling machinery, 315.

Sampling briquet material, 465.
Sandcoulee coals, Coking, 29.
Sawdust briquets, Cost of, 439.
Scaife trough washer, 61.
Schniewind, F., Ph. D., 381.

oven, 252.

Screens, Capacity of, 93.
Seibel oven, 223.

oven, Dimensions of, 226.

ovens, Cost of, 232.

ovens, Work of, 233.
Semet-Solvay coke oven, 263.

Solvay coke ovens, Improved, 273.

Solvaycoke, Structure of, 282.

Solvay plant at Dunbar, 273.

Solvay plant at Syracuse, 267.

Solvay plant. Cost of, 265.

Solvay plant, Cost of operating, 267.

Solvay tests, Comparison of, 271.
Shawmut Mining Company's experiments in

coking, Table of. 174.
Silica brick, 191.
Simon- Carves oven, 219.

Carves ovens, Cost and yield of coke in, 222.
Smith coke drawer, 187.

Specific gravities of coal and impurities, 56.
Speed and stroke of jig, 95.
Speeding and gearing of machines in washery,

Table of, 90.

Standard Coal Company's washery at Brook-
wood, Alabama, 75.
Statistics showing development of coke

industry, 133.
Stedman coal breaker and disintegrator, 50,

52.
Stein & Boericke washery, 122.

Walter M., Installation of Seibel ovens, 234.

washers, 69.
Stewart coal washer, 113.

washer, Table of results with, 116, 120.
Strength of anthracite and coke, 360.

of coke, Laboratory tests, 357.
Structure of anthracite in the Appalachian

coal fields, 8.

Stutz improved coal washer, 65.
Sulphate of ammonia, 232.
Sulphur, Conditions in which, is found, 45.

Effect of acetic acid in removing, 40.

volatilized in coking, Table. 39.

XX11

INDEX

Sweden, Briqueting in, 445.
Cost of briquets in, 447.

Tar.. Market for, 401.

Temperatures in Otto-Hoffman oven, 241.

Texas, Analyses of brown coals of, 12.

coal field, 12.
Thomas oven, 164.

Time required to make one ton of coke, 340.
Triassic coal fields, The Atlantic Coast, 7.

coals and cokes, Analyses of, 7.
Trough washers, 57.
Tuscarawas coal, Coking, in Germany, 335.

United Kingdom, Consumption of coal in

the, 381.

States, Briqueting in the, 462.
States, Coal fields of the, 5.
' States, Map of the coal fields of the, 6.
Utilization of the by-products of the coke
industry by Dr. Bruno Terne, 256.

Vancouver coals, Analyses of, 17.

Island coal fields, 17.
Varieties of coal, 20.

Wales, Briqueting in, 449.

Luhrig washer at Dowlais, 101.
Washer, Baum, 123.

Berard's, 63.

Diescher, 71.

Elliott, 59.

vScaife, 61.

Stein, 69.

Stewart, 113.

Stutz, 65.

Trough, 57.

Washery at Coahuila, Mexico, 79.

Cost of, 97.

of New Glasgow Iron, Coal, and Railway
Company, 70.

Speeding and gearing of machines in,
Table, 90.

Water and power required in, 91.
Washing coal, 56.

coal at Brookwood, Alabama, Table of
results, 79.

coal at Dowlais, Results of, 105.

coal, Cost of, 97.

coal, Improvement by, 97.
Water required in washery, Table of, 91.
Welland, Peat plant at, 455.
Welsh coal, Table of analyses of, 34.
Western coal field, 11.

coals, Analyses of, 12.
Westphalia, Analysis of coal, 244. -

Baum washing plant at Gladbeck, 128.

Brunck coke ovens in, 298.
West Virginia coal and coke, 270.

Virginia coals in Semet-Solvay ovens, 268.
Wharton coke oven, 152.

coke oven, Cost of, 154.

coke plant, 376.
Whitney coke plant, 375.
Wiesner briquet machine, 418.
Wood, Composition of, 21.
Work, costs, and products of several types of

coke ovens, 392.

World's product of coal, from 1901 to 1902
(Diagram), 3.

Yield of coke and by-products, Percentage,

258.
of coke in different ovens, 342.

Zeitz briquet press, The, 437.

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Full text of "Coke. A treatise on the manufacture of coke and other prepared fuels and the saving of by-products, with special references to the methods and ovens best adapted to the production of good cokefrom the various American coals"

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