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Lewis C. KARRICK

Low-Temperature Carbonization of Coal







[ Note: The original text of "LTC of Utah Coals" (available in the University of Utah Library) is over 800 pages long. Only the sections pertinent to the Karrick, Rexco, Hayes, NFC & Wisner processes that were selected as most suitable for use with Utah coals are represented in detail here; others are merely summarized. This representation provides a review of the many considerations involved in selecting and adapting a particular LTC process for each coal rank. Thus, you can "fill in the blanks" in this and the other LTC studies on this website and subsequently do it. ]



Low Temperature Carbonization of Utah Coals

by

R. Ketchum, et al.

A Report of the Utah Conservation & Research Foundation
to the Governor & State Legislature ( May 1939 )


Table of Contents

General Plan & Procedure
Forward
Introduction : Objectives & Scope of Work ~ Definition of Most Suitable Processes ~ Major Items of Programs ~ Acknowledgements.
Summary & Recommendations

Part I: Low Temperature Carbonization ( LTC )

Chapter 1. Introduction : History of Carbonization ~ High-T Carbonization ( HTC ) ~ LTC ~ Growing Importance of Smoke Elimination ~ Reasons for LTC Today.

Chapter 2. Technology, Problems & Products of LTC : Technology ( Definition of LTC, HTC, & Medium-TC ) ~ Problems (Summary) ~ Problems (Semi-coke ~ Tar ~ Fuel Gas ~ Liquor ~ Ammonium Sulphate) ~ Status Industry in Various Countries (USA ~ Great Britain ~ Germany ~ Canada ~ France ~ Belgium ~ Japan ~ Turkey ).

Part II: The Coals of Utah & A Summary of Published Data

Chapter 3. Coals of Utah : Reserves ~ Major Coal-Producing Counties ~ Types of Coal ~ Geology. [Not included here]

Chapter 4. Summary of Published Data : Types of Data ~ General Information (Physical, Chemical & Thermal Properties ~ Petrographic Studies ~ Coking Constituents ~ Briquetting) ~ LTC (Technology as Applied to Utah Coals  ~ Semi-coke & Byproduct Yields & Analyses) ~ Relationship of Previous Work to this Investigation ~ Summary.

Part III. Laboratory Investigations & Carbonization Studies

Chapter 5. Introduction : Objectives ~ Selection of Coals for Testing ~ Collecting & Testing of Samples (Chemical & Physical Tests) ~ Description & Properties of Coals Tested (Classification by Rank & Grade ~ Chemical Properties)

Chapter 6. Results of Carbonization Tests with Experimental Plant : Units of Measurement & Method of Stating Results ~ Tables & Figures ~ Yields of Carbonization Products (Semi-coke ~ Tar ~ Gas ~ Light Oil ~ Ammonium Sulfate) ~ Quality of Products (Semi-cokes ~ Mechanical Strength ~ Ignition Temperature ~ Gases ~ Tars (Data) ~ Light Oil ~ Liquor) ~ Summary (Thermal Distribution of Carbonization Products ~ Effects of Carbonizing Temperature ~ Effects of Blending ~ Effects of Retorts & Heating Media)

Chapter 7. Relation of Chemical & Physical Results to Yields of Carbonization Products : Tables & Figures ~ Yields of Carbonization Products ~ Results of Agglutinating-Value Test (Coal ~ Blends ~ Coal-Oil Mixtures) ~ Results of Plasticity Test ~ Summary [Not inlcuded here ]

Part IV. Processes for LTC

Chapter 8. Processes & Limiting Factors : Retorts & Heating Methods (Vertical Retorts ~ Horizontal Rotary Retorts ~ Modified Byproduct Coke Ovens ~ Internal vs Eternal Heating ~ Superheated Steam ~ Coal-Oil Mixture Processes ~ Limiting Factors in Selection of Processes (Classification of Processes).

Chapter 9. Minor Processes : Horizontal Externally-Heated Stationary Retorts (Bonnevie ~ Burney ~ Chown ~ Fellner-Ziegler ~ McIntire ~ Richards-Pringle ~ Summers) ~ Horizontal Externally-Heated Rotary Retorts (Bituminoil ~ Dobbelstein ~ Fusion ~ KSG ~ Mequin ~ Raffloer ~ Shgeffield & Lloyd ~ Thyssen) ~ Horizontal Internally-Heated Retorts (Holford ~ Morgan ~ Pehrson ~ Reed-Lamie ~ Sauerbrey) ~ Vertical Externally-Heated Stationary Retorts (BT ~ Berg ~ Bowing ~ Carbolux ~ Carlton ~ Crozier ~ Fuel Res. Brd. ~ Holcobami ~ Illingweorth ~ Krupp-Lurgi ~ Otto ~ White) ~ Vertical Internally-Heated Stationary Retorts (Davies ~ Dual Gas ~ Haken ~ Hood-Odell ~ Kolergas ~ Lamplough ~ McEwen-Runge ~ Midland ~ Pintsch ~ Plauson ~ Seidenschnur-Pape ~ Sutcliffe-Evans ~ Turner) ~ Coal-Oil Mixture Processes (Bluemner ~ Carbonol ~ Cranston ~ Dvorkovitz ~ Greenstreet ~ Knowles ~ Lewis ~ Meiro ~ Mondello ~ Ryan ~ Stephenson ~ Strevens ~ Struban) ~ Producer-Type Processes (Bussey ~ Hanl ~ Maclaurin ~ Modified Mond) ~ Miscellaneous Processes ( Ab-Der-Halden ~ Babcock ~ Bostaph ~ Carburite ~ Eesti-Patendi ~ Freeman ~ Geissen ~ Greene-Laucks ~ Hereng ~ Hinselmann ~ Honigman-Bartling ~ Moore ~ Parr ~ Piron-Caracristi ~ Plassman ~ Prudhomme ~ Roser ~ Salermo ~ Stevens ~ Thermax ~ Trentha)

Chapter 10. Major Processes : Horizontal Externally-Heated, Rotary Retorts (Davidson ~ Hayes ~ Wisner) ~ Horizontal Internally-Heated Rotary Retort (Suncole) ~ Vertical Externally-Heated Stationary Retorts (Coalite ~ Hird) ~ Vertical Internally-Heated Stationary Retorts (Coalene ~ Derby-Horner ~ Karrick ~ Lurgi ~ NFC ~ Rexco ~ Trumble) ~ By-product Coke Oven type Processes (Gibbons/Cellan-Jones ~ Kemp ~ Lecocq) ~ Coal-Oil Mixture Processes (Cannock ~ Gifford)

Part V. Technical & Economic Factors Concerning Application of LTC to Utah Coals

Chapter 11. General Considerations ~ [Not included here]

Chapter 12. Economic Analysis of Major Processes : Results & Explanation of Table 19 (Calculated Delivery Prices of Semi-Cokes for Hand- & Stoker-Fired Installations  ~ Disposal of Tar & Gas) ~ Value of Table 19.

Chapter 13. Selection of Most Suitable Processes : Application of Major Processes to Local Requirements ~ Semi-Coke for Use in Existing Hand-Fired Combustion Equipment (Carbonization of Coking Coals & Blends in Modified Byproduct Coke Ovens & Other Methods & Coal-Oil Mixtures) ~ Briquetting Processes) ~ Semi-Coke for Use in Existing Stoker-Fired Combustion Equipment.

Chapter 14. The Most Suitable Processes : Semi-Coke for Use in Existing Hand-Fired & Stoker-Fired Equipment.

Chapter 15. The Proposed Erection & Operation of a Semi-Commercial Plant (Processes to be Used in Semi-Commercial Plant)

Part VI
Apparatus & Procedures Used for Conducting Laboratory Investigations & Carbonization Studies

Chapter 16. Sampling Coal at the Mine : Problems ~ Methods

Chapter 17. Modified Agde-Damm Plasticity Test : Object ~ Apparatus ~ Procedure & Corrections ~ Results

Chapter 18. Agglutinating-Value Test as Applied to Utah Coals

Chapter 19. Apparatus & Procedure for Conducting Carbonization Studies : Sampling & Preparing Cal for Tests (2500 lb Sample ~ Retort Charge) ~ Carbonization Studies with Experimental Plant (Description of Apparatus: Static & Rotary Retorts ~ Condensing & Scrubbing Train ~ Meters & Gas Sampling ~ Measuring Apparatus) ~ Test Procedure ( Vertical Retort, Slow External Heating ~ Rotary Retort, Slow External Heating ~ Vertical & Rotary Retorts, Rapid External Heating & Superheated Steam) ~ Determination of Yields & Examination of Products (Semi-Coke: Yield, Shatter Tests ~ Chemical & Ignition Tests ~ Gas Yield & Analysis ~ Tar & Liquor Yield, Examination, & Separation)

Part VII. Review of US Patents Covering Processes & Apparatus for LTC

Bituminol ~ Carlton ~ Coalene ~ Coalite ~ Davidson ~ Derby-Horner ~ Dobbelstein ~ Dvorkovitz ~ Fenton ~ Gibbons/Cellan-Jones ~ Greene-Laucks ~ Hayes ~ Hird ~ Holcobami ~ Hood-Odell ~ Illingworth ~ Jenson ~ Karrick ~ McEwen-Runge ~ NFC ~ Parker ~ Parr ~ Piron-Caracristi ~ Reed-Lamie ~ Rexco ~ Salermo ~ Suncole ~ Sutcliffe-Evans ~ Trumble & Ramage ~ White ~ Winzer ~ Wisner

Part VIII. Selective Bibliographies

Abbreviations Used ~ Utah Coals (History ~ Geology ~ Mines & Mining ~ Industry ~ Research ~ Processing & Firing Methods ~ By-products ~ Smoke Problem in Salt Lake Valley) ~ LTC (Books ~ General & Economic ~ Processes ~ Byproducts) ~ Cancer Caused by Derivatives of Coal ~ Oil Shale (Books ~ Bibliographies ~ General & Economic ~ Geology ~ Mining ~ Testing & Processing

Part IX
Appendix [Not included here]

State Law: Motor Fuel Tax ~ Articles of Incorporation, Utah Conservation & Research Foundation ~ Appropriation Bill Submitted to Utah State Legislature

Tables [Not included here]
Illustrations [List not included here]


Summary & Recommendations

Summary ~

I. As shown in Chapter 1, LTC is not a new field of endeavor. It had its beginning late in the 17th century in England when the main object in treating coal was to obtain oil. The year 1880 marks the beginning of coal carbonization for the production of a solid smokeless fuel or semi-coke, and the last 30 years have seen the greatest activity.

II. Published results of previous investigations concerned with LTC of Utah coals are sources of incomplete and general information which cannot be adequately correlated to provide a sound basis for the solution of the problems of this investigation. The agglutinating, plastic, and by-product making properties under various carbonizing temperatures and heating methods of the commercially important Utah coals, have not been determined previously and the results compared systematically. (See Chap. 4)

III. Systematic laboratory investigations and carbonization studies were made with the commercially important Utah coals under various carbonizing temperatures and heating methods. The commercially important coals are the bituminous coals of Carbon and Emery counties and the sub-bituminous coal of the Coalville area. Results of these studies are reported in Part III and are summarized below.

(1) Semi-coke with the greatest mechanical strength is produced with the vertical, externally-heated retort; whereas, semi-coke with the lowest mechanical strength is obtained with the rotary, externally-heated retort.

(2) The rotary retort yields the maximum amount of tar. A minimum yield of tar having the highest specific gravity and viscosity is produced in the vertical retort heated internally with superheated steam [i.e., Karrick Process].

(3) A maximum yield of fuel gas is obtained with the rotary retort while the vertical retort heated internally with superheated steam yields the minimum amount of fuel gas with the highest heating value.

(4) Higher carbonizing temperatures increase the yield of fuel gas, ammonium sulfate, and a slight extent the tar above 550° C. At the same time, the heating value of the fuel gas and its specific gravity is decreased. The ignition temperature of the semi-coke increases with carbonizing temperature, the lower temperatures yield products having the maximum total economic worth. Rapid heating in the manner used in this investigation is detrimental to the mechanical strength of the semi-coke.

(5) The agglutinating value test as applied to Utah coals is a more reliable method of determining the coking properties of these coals than are the often times advocated hydrogen-oxygen ratio, carbon ratio, and oxygen content of the raw coal. The agglutinating value of the best coking Utah coal is far below the values given for coking coals of the eastern part of the country. A satisfactory semi-coke can be produced by blending this coking coal with weakly-coking Utah coal only when from 35 to 95% of the coking coal is used. The plasticity tests give results that further substantiate the data obtained with the agglutinating value tests. Results of these two comparatively simple laboratory tests are indicative of the mechanical strengths of semi-cokes produced in vertical or rotary retorts.

With the exceptions noted, the bases for the following statements may be found in Part V of this report:

IV. The principal objective of LTC in Utah is to manufacture from Utah coals a reasonably priced semi-coke to satisfy the growing demands for a clean and smokeless fuel-- and at the same time may be an important factor in reestablishing Utah’s coal industry on a sound economic basis.

V. The production of semi-coke suitable for use in existing hand-fired combustion equipment is of first importance, since most of the smoke comes from these installations. This semi-coke may be either in various sizes from slack to pea or in a briquetted form.

VI. The production of semi-coke in small sizes suitable for use in existing stoker-fired combustion equipment is of secondary importance. Little smoke is created from automatic coal-burning devices when they are properly regulated and operated. However, smoke is sometimes produced by these installations particularly during startup periods or when the furnaces are being fired in excess of their capacities. Increased efficiencies may be obtained with semi-coke in comparison to raw coal, and the use of this new fuel might prove to be more advantageous provided that its cost would be no greater than the cost of raw coal on the basis of available heat units.

VII. Semi-coke should be produced, if practicable, from the commercially important Utah coals in order that all of the coal operators may be able to take advantage of LTC. Semi-coke may be made from both coking and non-coking coals, whereas by-product coke, a basic material in the blast furnace smelting of lead and iron ores, must be made from coking bituminous coals only. As a conservation measure, therefore, the production of semi-coke from the comparatively smaller reserves of the best coking coals of the state, if not eliminated completely, should be reduced to a minimum. Thus we may take the fullest advantage of our valuable reserves of coking coal, without which the present smelting industries of Utah could not operate economically.

VIII. Semi-coke for use in existing hand-fired combustion equipment must not sell at a price greatly in excess of the present retail price of 8" lump coal, otherwise its use would not be widespread and the smoke problem, although reduced, would still be in existence... Also, the semi-coke should be clean, burn readily and efficiently, and be sufficiently strong to withstand normal handling without excessive degradation.

IX. The delivered price of semi-coke for stoker purposes should not be greatly in excess of the present retail price of slack coal... The fuel should be clean, burn readily and efficiently in existing combustion equipment, but need not necessarily possess the strength requirements of semi-coke for hand-firing purposes.

X. Part IV describes 101 processes for LTC. These processes are divided into Major and Minor Processes according to the classifications given in Chapter 8. It is from the Major Processes, 18 in all, that the most suitable processes were chosen. For details concerning the selection of these processes see Chapter 13.

XI. The fundamental definition of the most suitable processes is given in the Introduction of this report, and is reproduced below as follows:

The processes most suitable for the treatment of Utah coals by LTC are those methods, impartially selected from known LTC systems, that are capable of producing at the minimum total cost from the commercially important Utah coals, the maximum yield of semi-coke of the best quality that is consistent with the maximum yield of by-products that have the maximum total economic worth.

XII. The most suitable processes for the manufacture of semi-coke in sizes from slack to pea or somewhat larger sizes from non-coking bituminous Utah coals, are the Rexco and NFC (National Fuels Corp.) processes...

XIII. The most suitable process for the manufacture of semi-coke in briquetted form from non-coking bituminous Utah coals, are the Hayes and NFC processes.

XIV. The production of semi-coke in small sizes from bituminous Utah coals is not considered to be economically sound because the estimated delivered prices of the carbonized fuels are greatly in excess of the present delivered price of raw slack coal. According to the data obtained, the most economical coal for the production of semi-coke in small sizes is the sub-bituminous coal of the Coalville area.

XV. The Hayes process is the most suitable method for the manufacture of semi-coke in small sizes from sub-bituminous Utah coal... The Wisner process may also be suitable on the basis of confidential cost data which have been withheld from publication...

Recommendations ~

The problems attending the economic production, marketing, and distribution of semi-coke and by-products from LTC of Utah coals may be soundly determined only by the operation in Utah of a properly designed and supervised semi-commercial plant. The Foundation therefore recommends as the next logical step the erection and operation of a semi-commercial plant using retorts of commercial size. The plant should be... operated continuously for a period of at least one year in order to:

(1) Adequately determine the nature and the extent of profitable markets for semi-coke,

(a) In various sizes from slack to pea size or somewhat larger sizes, and in briquetted form for use in all existing types of hand-fired combustion equipments, and

(b) In slack sizes for use in all existing types of stoker-fired combustion equipment.

(2) Accurately determine the operating costs for the carbonization methods employed, which thus far have been estimated on the basis of previous experience with installations in other localities and with other coals.

(3) Determine the commercial yields of products for each of the systems employed. These data have been obtained previously with Utah coals in carbonization equipment on an experimental scale.

(4) Determine the best operating technique for each of the systems employed from the standpoint of technical and economic considerations.

(5) Develop profitable markets for the tar, light oil, and fuel gas.

In conjunction with the semi-commercial plant, an adequate research laboratory should be provided in order to:

(1) Insure that the operating efficiency of each of the carbonization systems is maintained constant and is as high as possible.

(2) Insure that the quality of each product is maintained constant and that it meets the specifications required for its most profitable sale.

(3) Establish a proving ground for ideas and methods to improve upon the operation of the plant.

(4) Fundamentally and scientifically investigate the properties of the tars in order to develop new products that will find a profitable and ready market. For tangible results, research of this nature of this nature should be conducted continuously over a period of several years.

After one year of continuous operation of the semi-commercial plant, it is hoped that the most efficient and economic processes of those named herein could be adequately determined. Also it is hoped that sufficient information would be available from which to judge whether or not a commercial plant should then be erected. Research work on the tars should be conducted continuously over a period of several years. Also it would be well to conduct additional studies of Utah coals in order to learn more about their properties and characteristics.

In order to carry out the above-named objectives by the operation of a semi-commercial plant, combinations of the most suitable processes hereinbefore named, may be made according to the following plans.

Plan I. The Hayes and the NFC (National Fuels Corp.) processes may be used in order to minimize the amount of money required for the plant. Briquettes could then be made by each process and their respective properties and uses determined. Semi-coke in various sizes from slack to pea could be made by the NFC method. Also, semi-coke in slack sizes could be made by the Hayes process.

Plan II. The Hayes, NFC, and Rexco processes may be used. In addition to the operation of the Hayes and NFC processes for the purposes named under Plan I, semi-cokes in various sizes could be made by the Rexco and NFC methods and their respective properties and uses determined.

Plan III. The Hayes, NFC and Wisner processes may be used in addition to the operation of the Hayes and NFC processes named under Plan I, semi-cokes in slack sizes for stoker uses could be made by the Hayes and Wisner processes and their respective properties and uses determined.

Plan IV. The Hayes, NFC, Rexco and Wisner processes may be used. In this way, the technical and economic feasibility of all of the most suitable processes could be determined together.

For each of these Plans, a common condensing and gas-scrubbing system could be employed.


Part I
Low Temperature Carbonization (LTC)

Chapter 1

Introduction ~

Carbonization is the term used to denote the general process of removing the free moisture and volatile matter from coal and other solid carbonaceous materials by the application of heat in the absence of air. Three major products are thus manufactured, viz: (1) a solid, smokeless, carbonized residue; (2) tar, and (3) fuel gas.

To carry out the process, the material to be treated is placed in a suitable oven or retort to which heat is applied. The water and volatile matter distilled from the coal leave the container in vapor form, and are conducted to cooling equipment in which the water and tars are condensed and recovered as liquids. The artificial fuel gas may then be passed through scrubbing towers to remove ammonia and sulfur compounds, and also a light oil or crude gasoline. A suitable receiver may be provided for the storage of the fuel gas. The water, commonly known as liquor, may be circulated through the condensers as a cooling medium, or wasted as a valueless product. Ammonium sulfate for the manufacture of fertilizer may be produced also.

History of Carbonization

High Temperature Carbonization (HTC) ~

The first attempts to carbonize coal were carried out in the 16th century. The main objective at that time was the removal of sulfur from coal, and accordingly the process was called "desulphurizing" (# 521). In 1584, Julius, Duke of Brunswick, and Stumpfell in Anhalt, Germany, recommended coal carbonization. In 1589, Proctor, Petersen, and Dudley tried to carbonize coal in England. These are the first historical records of the manufacture of coke. Coal was treated in the same way as wood for the production of charcoal; it was piled in heaps on the ground and carbonized.

Not until the 18th century, however did the carbonization process reach any degree of technical importance. At that time, it was stimulated by the activities of the iron industry. Coke was manufactured in several types of closed ovens as early as 1760. Closed coke ovens were built in England as early as the beginning of the last century. Because of their shape, they were called "beehive ovens". An equal distribution of heat was obtained by covering the top of the oven with a circular arch some distance above the base. The heat from the arch radiated to the upper layers of the coal charge, and produced an equal temperature throughout. The distillation gases developed in the beehive oven were allowed to burn inside the coking chamber, and the resulting products of combustion escaped through the charging hole in the arched crown. Air required for combustion was allowed to enter through slots provided in the discharge door on one side of the oven. Heat required to produce carbonization was obtained by subjecting a certain amount of the charge to combustion which resulted in a low coke yield. However, the coke was of such excellent quality that for a long time the prevailing opinion, particularly in England, and the US, was that a first class product would be manufactured only in this type of oven.

The manufacture of tar, fuel gas, and various compounds from the distillation products was later advocated. While by-product recovery had its beginning in France, yet Germany took the lead in its development. In 1881, A. Huessner and Dr C. Otto tried independently to design equipment for this purpose. Dr Otto’s ovens were extensively used in Germany, and to him is given the honor of being the outstanding pioneer in this field.

The by-product coke industry in the US is now 43 years old. At the end of the 19th century, there were 120 Otto ovens and a considerable number of Selmet-Solvay ovens in operation in this country. In the days before the introduction of the by-product coke oven, metallurgical coke was produced in wasteful beehive ovens. Now, byproduct coke ovens that recover the gas and other valuable by-products, produce approximately 90% of all coke made in the US, only 10% being produced in beehive ovens.

Low Temperature Carbonization (LTC) ~

Low Temperature Carbonization (LTC) was first advocated for the production of tar or oil from coal, since the yield is much greater from this method than from high-temperature carbonization.

According to Briggs (# 571), "The production of oil by low temperature distillation of coal is still so frequently regarded as a development of late years that it is, perhaps, not sufficiently realized that the coal-oil industry flourished in Great Britain and elsewhere during mid-Victorian times. Even among those to whom the existence of the industry and the general circumstances of its decline and eventual extinction are known, it is, I believe, seldom appreciated how advanced a stage of technical development was reached by the distilling companies of that period".

Mr Briggs has also pointed out that in 1861 Dr A. Gessner, a consulting chemist, published a book in New York entitled "A Practical Treatise on Coal, Petroleum and Other Distilled Oils". He claimed to be the first in America to produce oils successfully from coals. In fact, he made oil from coal in 1846, and exhibited lamps burning the oil at Prince Edward’s Island and at Halifax, Nova Scotia.

"Early though that may be for America", Mr Briggs says, "The history of coal-oil on this side of the Atlantic (Europe) reaches back much further still. The manufacture appears to have originated in this country (England). The first reference is to be found in the Records of the patent Office; it relates to a patent (# 214) granted in 1681 to J. Becher and H. Searle for the manufacture of pitch and tar from coal, but no description of the operation is given". More to the point is Patent # 330 of 1694, granted to M. Hancock and W. Portland, and entitled, "A Way to Extract & Make Great Quantityes of Pitch, Tarr & Oyle out of a Sort of Stone of which there is Sufficient Plenty in England & Wales". One looks in vain for an account of either the "Way" or the "Stone" in the specifications.

"The year 1839 is noteworthy for the patent of Alexander Cruckshanks (# 8141), who introduced the blending of coking and non-coking coals and the utilization of the gas generated during distillation for heating the stills. He also steamed the charge during retorting.

"About this period, or a little earlier, the distillation of peat was commenced in Germany and Ireland. During the ‘40s the manufacture of tar, oils, and paraffin-wax from peat reached respectable dimensions, especially in the latter country, and continued as a renumerative business until extinguished by the inflow of American petroleum.

"It will be more profitable to return to 1850, the year of Young’s famous patent, and to sketch out the progress of the coal-oil industry in other regions. That patent (# 13,291), entitled "Improvements in the Treatment of certain Bituminous Mineral Substances and in Obtaining Products Therefrom", described the operation of retorting coal in a common gas-retort. Care was exercised not to allow the temperature to rise above a low red heat so as to prevent, as far as possible, the products being converted into permanent gas. The maximum yield was obtained when the temperature was the lowest at which the distillation was complete and when the heat was raised slowly. The retort worked intermittently, being emptied after the volatile products ceased to be expelled, cooled somewhat, and then recharged. The tar was condensed in a worm kept at about 55° F by means of cold water. It was then heated in a cistern to 150° F and allowed to stand for a day. The water and many impurities having settled to the bottom, the tar was led away and distilled in an iron still. The oil, having condensed in a worm, was treated with oil of vitriol, 10 gallons of the acid being gradually added to 100 gallons of oil. After stirring one hour and settling 12, the floating oil passed into an iron vessel, where caustic coda solution was added in the proportion of 1 part alkali to 25 parts of oil. After agitation and settling, the product was distilled to take off the spirit. The remainder was again treated by vitriol and then by ground chalk; after that it was kept at about 100° F for a week. Paraffin-wax was deposited from the oil on cooling and was extracted therefrom by means of a filter-press. The purified liquid found a market as lubricating oil.

"I have given a more ample summary of Young’s specification than of any other, because it is a prominent landmark in the history of the oil industry, and shows how long ago the chief operations of oil-refining were understood and practiced. When it is added that ‘cracking’ was discovered in 1861 it becomes clear that, if they were not able to command our resources in dealing with oil and its products in great volume, our grandfathers were at any rate familiar with the essentials of retorting and distillation. The only fundamental process in the repetoire of the modern oil technologist of which they knew nothing was hydrogenation. They more than compensated for that lack, however, by their assiduity in selecting for retorting those carbonaceous minerals richest in hydrogen, and, in this regard, they were, perhaps, wiser in their generation than we are in ours.

"We learn that, between 1781 and 1860, more than a hundred patents were taken out in Europe and America for the manufacture and purification of oils from coals and other bituminous substances, and over 40 were granted to retorts, stills, and other appliances connected with the industry.

"About 1860, at the heyday of the coal-oil industry in the States, between 50 and 60 plants were producing oil from cannels, bituminous shales, and imported Boghead, They were situated in Massachusetts, New York, Pennsylvania, Ohio, Kentucky, Virginia, and Connecticut. Furnaces, the ruins of which are still said to exist, were also erected by the Mormons to treat Utah oil-shale. Many if not most of these American works were of small capacity, and the greater proportion had barely started operations when the discovery of petroleum threatened their prompt extinction. Fortunately, however, their owners were able with but little trouble to convert the factories into oil refineries and so weathered the storm."

Later on, LTC was advocated for the production of smokeless fuel to rid the atmosphere of smoke caused by the burning of raw coal. In 1880, according to Gentry (# 519), ?Scott Moncrieff proposed to free the atmosphere from smoke by partially coking the coal in high-temperature retorts. Investigations, however, proved that only the outer layers of coal had been partially coked when removed from the retorts and the core remained as raw coal. Ten years later Parker, the inventor of the Coalite process, secured a patent (# 67) for the production of a smokeless fuel by distillation with superheated inert gases, such as steam, water gas, or coal gas, at 600° to 650° C. Later, Parker obtained Patents (# 14,265 and 17,347) for heating coal in the presence of steam below 450° C. These formed the basis upon which the Coalite process was developed (See Chap. 10).

Gentry further states that, "In the US, experiments had meanwhile been carried on from as early as 1902 at the University of Illinois. An announcement of the results was made in 1908 and further results were reported in 1912 by Parr and his various coworkers. While some of the earliest research on this subject was made in the US, it has been extended, until recently, mostly by countries with limited or no petroleum resources and which recognized that their coal deposits could be made to yield a liquid fuel which would be of national importance".

In the last 30 odd years, at least 800 processes have been proposed and many plants have been installed in various parts of the world to carbonize coal and similar materials at low temperatures.

Growing Importance of Smoke Elimination ~ [ Not included here ]

Reasons for LTC Today ~

In the US, the primary reason for the LTC of coal today, is the production of a free-burning solid smokeless fuel from coal. The increasing interest and activity in this field at the present time may well be indicative of the future trend in the utilization of our coal resource.

There are still ample reserves of natural petroleum in this country to satisfy the demand for petroleum products for a continued period of time. Be this as it may, it appears that unless vast oil reserves are discovered in the not too-distant future, LTC may play an important role in the manufacture of oil and its products from coal, oil shale, and other oil-producing materials.


Chapter 2

Technology, Problems & Products of LTC & Status of Industry in Various Countries

Technology ~

There are many excellent books and publications which deal with the technical details of carbonization at both low and high temperatures. The information essential to a general understanding of the subject is presented briefly in the following paragraphs, with the intention that the reader who may be interested in securing details will consult the references listed in the bibliography in Part VIII of this report.

The yield and quality of the products of carbonization not only vary with the coal used, but also with the manner in which the volatile products are distilled and removed from the retort.

Investigations have shown that below 750° C (1382° F) or thereabouts, the fuel gases are richer in carbon dioxide, methane, and ethane and contain smaller percentages of hydrogen than do the gases liberated at higher carbonizing temperatures. Above this temperature, methane and ethane are decomposed to give an increase in hydrogen content, the degree of decomposition being greater for the higher carbonizing temperatures. Thus it is said that below 750° C the volatile products undergo primary decomposition only, and that above this temperature secondary decomposition occurs.

It does not always follow that secondary decomposition may not take place at lower temperatures. In fact, the volatiles are further decomposed if their path through the retort is toward a zone of higher temperatures than that at which the vapors are formed. On the other hand, if the volatiles are continuously withdrawn to a zone of lower temperature or away from the source of heat, little if any secondary decomposition occurs. Moreover, the longer the distillation products remain in the retort, the greater is the opportunity for secondary decomposition.

Secondary decomposition results in (1) a high yield of fuel gas of low heating value, (2) a low yield of tar, and (3) a decomposition of graphitic carbon on the coke which makes it hard to ignite but tends to increase its mechanical strength.

Primary decomposition produces (1) a low yield of fuel gas of high heating value, (2) a high yield of tar, and (3) a coke having an active form of carbon which makes for easy ignition and free-burning properties. The term "semi-coke" is generally used to distinguish the solid carbonized product made under condition of primary decomposition from that produced by secondary decomposition. The tar is often referred to as "primary tar" or "tar-oil".

Definition of LTC ~

Low Temperature Carbonization (LTC) is the destructive distillation of coal, oil shale, and other solid carbonaceous materials, under such temperatures and other conditions, wherein the secondary decomposition of the volatiles is a minimum, a relatively low yield of high Btu gas is evolved, a maximum yield of tar is obtained, and the coked residue is an active form of carbon. The temperatures most generally employed range from 900° to 1200° C (1652° to 2192° F).

Definition of Medium Temperature Carbonization ~

Medium-temperature carbonization (MTC), now being advocated for reasons which follow, is the destructive distillation of coal under such temperature and other conditions wherein some secondary decomposition of the volatiles occurs, and the yield and quality of the tar and coked residue are midway between the corresponding items of the same products from high- and low-temperature carbonization. The temperatures most generally employed range from 750° to 900° C (1382° to 1652° F).

The controlling factor in the general classification of carbonizing methods is the degree of secondary decomposition to which the volatile products are subjected. The temperature ranges indicate above are approximate only, and are given solely for practical purposes according to generally accepted criteria.

For both high- and low-temperature carbonization processes, coking bituminous coals are always employed, although in some cases blends of these coals are made with coals of the weakly-coking or non-coking varieties. Coking, weakly coking, and non-coking bituminous coals are used by LTC systems. However, there are some of these methods which are suited especially for the treatment of bituminous coals, lignites and peats.

Problems ~

LTC has met with many difficulties of both technical and economic natures. Its history has been colored by the actions of sharp-tongued promoters who were able to secure large sums of money on the strength of fanciful claims and unfounded declarations. This situation was true particularly during the first 30 years of the present century, when it was generally believed that huge profits could be made in this field with but little effort and without previous engineering and economic investigations. Because of many failures and financial disappointments, LTC thus received a "black eye" which to this day has not been removed entirely.

However, the experience gained during this period brought to light the fundamental difficulties that prevented technical success. Gentry (519) has aptly summarized these difficulties as follows:

"A review of the numerous patents on methods for effecting the distillation of carbonaceous materials and a study of many attempts to solve the practical difficulties lead at once to the conclusion that many otherwise creditable efforts have failed because of lack of knowledge regarding the behavior of coal and of its distillation products with respect to variations in temperature and other physical conditions. In other cases, where the behavior of coal has been well understood, failure can be attributed often to lack of knowledge of the properties of materials under severe conditions and to unforeseen operating difficulties".

Early inventors and experimenters believed that because of the LTC temperatures, less heat would be required for the process and the investment and operating costs would be materially lower than for high-temperature carbonization. But experience showed that certain inherent characteristics of coal and thermodynamic laws prevent the complete realization of these hopes.

In the first place, coal is a poor conductor of heat. At the higher carbonizing temperatures, the rate of heat transfer is much greater than at the lower temperatures. In the latter case, therefore, carbonization requires more time per unit weight of coal: the throughput per unit of retort volume is decreased; and the processing costs are increased. Heat requirements have now closely approached those for high-temperature practice in come cases, and may be considerably greater in other instances.

With some of the earlier types of retorting methods, it was found that only the outer layers of the coal were carbonized and that the coal in the center of the retort had not been treated. This condition was caused by the low heat gradient and poor conductivity of coal, in addition to the method of heat application.

As discussed in Chapter VII of this report, coking coals swell during a portion of the period in which the transformation from coal to coke takes place, and subsequently shrink upon further heating beyond the swelling stage. Unless they are strongly-swelling coals, sufficient shrinkage occurs at elevated temperatures to allow easy discharge of the coke from the oven. At reduced temperatures, however, shrinkage takes place to a lesser degree and removal of the semi-coke is often difficult is not impossible.

With some coals and retorting methods, a layer of carbon may be deposited on the inside of the retort. Unless means are taken to prevent its formation, this material reduces the rate of heat transfer to the coal, results in increased production costs, and necessitates frequent shutdowns for cleaning purposes.

A great deal of research work has been required before satisfactory explanations could be made of many of the results obtained with various systems of LTC. That is, the mechanism of carbonization, and the constitution and the carbonizing properties of coal had to be determined. We now know that coal is a very complex heterogenous substance, that each and every coal possesses different properties, and that when these differences are great, different methods of carbonization are required.

In addition to problems arising from certain properties of coals, mechanical difficulties were also encountered. Localized heating caused warping of the retort. Air-tight seals were sometimes troublesome and expensive to install. Uniformity of carbonization throughout the charge was likewise not accomplished in the early retorts, and numerous other problems of this nature may be enumerated.

All of the modern byproduct ovens are built according to one common heating principle, that is, the external application of heat to a vertical, intermittently charged, rectangular brick oven. On the other hand, there are many different ideas for carbonization at low temperatures. One school will insist on treatment in thin layers; a third will demand static conditions, but no insistence on thin layers; a third will stipulate that each particle of coal must come in contact with the heated surface or heating medium; a fourth will demand continuous treatment and operation, and so on. One writer (1069) has stated the case as follows:

"These multifarious operating difficulties inherent in LTC inspired the invention of equally multifarious apparatus designs. Each separate problem seems to have been singled out by somebody for special attention. Thus in a few short years, a vastly greater variety of equipment appeared on the scene than was ever observed in high temperature practice in its whole long life. Not only were some processes continuous and others intermittent, but both external and internal heating had their staunch supporters. For the heating medium itself, there were many choices: combustion products, steam, reheated coal gas, or even air where it was desired to burn part of the coal to supply heat enough to carbonize the balance... Few standard pieces of industrial processing equipment escaped serving as the prototype of at least one low-temperature carbonization process. Thus, in effect, coal was carbonized in cement kilns, blast furnaces, producers, blue-gas generators, smoke stacks, ball mills, and in almost every conceivable type of conveyor, whether belt, paddle, drag or screw".

Summary ~

From the foregoing, it is evident that a comprehensive analysis of the many processes is not a simple one, and that the sound application of LTC to a given set of coals and economic conditions requires a special investigation. Previously obtained technical and economic data for similar coals and conditions in other localities cannot be wisely applied to adequately solve the problems at hand, since each set of coals possess their own peculiar carbonizing properties and the problems vary from one locality to another.

Out of the many experiences gained in the past, have come certain definite conclusions with regard to the development of a LTC industry in any given locality. These conclusions have been expressed in the writings of several authorities (# 834, 882, 978, 1090) and are presented in combined form in the following paragraphs:

(1) A thorough and reliable study must first be made of the fundamental carbonizing properties of the coals to be treated.

(2) Suitable methods of LTC must then be chosen, and these must be investigated under laboratory conditions, where the varying factors involved can be subjected to close control, and where relatively high accuracy of measurement can be obtained.

(3) The methods are carried a stage further by erecting an intermediate-scale unit, with a view to obtaining further design data for a still larger unit. In this stage the plant will probably deal with several hundred pounds a day.

(4) Making use of then information yielded in stage (3), a full-scale unit must now be erected and operated. The size of this unit would depend upon the type of plant, but might range between, say 5 tons and 100 tons daily capacity. It is essential that the plant be arranged so that additional retorts may be added to bring the production up to any desired quantity.

(5) If the results of the above work indicate that both technical and economic success may be attained, then a commercial installation of several units similar to those developed in stage (4) would be erected in some favorable locality, and the economic possibilities of the system finally determined in actual practice.

(6) Continuous research should be conducted to improve the carbonizing technique to develop new uses for all the products, and also to manufacture new products.

Products ~

Semi-Coke: The characteristics of low-temperature semi-coke depend on the coal from which it is made and the system of carbonization used. To satisfy all general demand to the consuming public, it should, however, possess the following properties: (1) must be smokeless, (2) readily kindled), (3) burn vigorously and be easily controlled, (4) have a high radiant efficiency, (5) be able to withstand normal handling and transportation, (6) be dense and compact, (7) have a volatile content between 5 to 20%, (8) have an ash content below 8 and in some cases 10%, (9) require minimum attention during combustion, and (10) have a uniform texture.

The greater number of semi-cokes are produced in the form of small lumps, although some are in powdered form for steam production and others are briqueted for domestic use.

Semi-coke may be used as an ideal domestic fuel for open fires, stoves, or furnaces. There are also other uses not as well known. Activated carbon can be obtained by carbonizing selected coals of the hard durain type which do not intumesce or fuse upon carbonization at 500° C (932° F). The semi-coke thus produced is then activated with steam at 950° C (1742° F) whereupon about 75% of the fuel is gasified, leaving a residue of 25% activated carbon. This material is then crushed and graded for various uses. The first-grade product may be used in gas respirators. Another grade may be made for solvent or benzole recovery. Still another grade will decolorize sugar liquor. Liquids may be decolorized efficiently by finely divided activated carbon.

The industrial uses of semi-coke include heat treatment of metals, drying processes and production of steam. The most recent developments include such diverse uses as soil warming and orchard heating, fog dispersion at airports, and as fuel for tractors. In Europe, numerous producer-gas-driven vehicles are being operated with apparent success. Particularly in Germany, ships are said to be operating satisfactorily using producer gas generated from semi-coke.

References to more detailed information on this subject will be found in Part VIII.

Tar: Low-temperature tar contains two main types of compounds: neutral hydrocarbons and phenolic compounds. The former resembles paraffin-base crude petroleum, consisting principally of alipathics with a proportion of naphthalene derivatives and aromatic compounds with extensive sidechains. The latte consists of compounds containing one or more phenolic hydroxyl groups, the number depending on the oxygen content of the raw coal.

High-temperature tar has a similar composition than low-temperature. The former is benzenoid in character, while the latter is more parafinoid. The properties and uses of HT tar are well established, since this type of carbonization has been practiced commercially for a considerable time. However, LT tar has not yet been manufactured continuously in commercial quantities, and hence there has been no pressing demand for extensive research. Thus, comparatively little is known about this product, and further research is necessary before it may be commercially and profitably utilized.

The principal method of refining crude tar is by distillation according to present oil-refining methods. Within the last few years hydrogenation has gained interest and many studies have been and are now being made to insure its commercial feasibility. Hydrogenation reduces the tar acids to low-boiling oils for use as a motor fuel. The entire fraction up to 400° F and freed of tar acids, bases, and unsaturated material, may be used in internal combustion engines. Crude low-temperature tar may be fractionated so as to obtain a distillate suitable for fuel oil. Other products of LT tar which can be utilized commercially are: cresylic acid, for making plastics of the phenolic-formaldehyde group, also for disinfectants and flotation reagents; phenolic fractions, distilling between 205° C (401° F) and 290° C (554° F) and dissolved in caustic soda, for use in mercerizing cotton; creosote oil, for use in treating fiber; and benzole (refined light oil), for increasing the octane number of petroleum gasoline.

Fuel Gas: Fuel gas, from LTC of coal, varies both in quantity and quality depending on the composition of the raw coal, and also upon the process and temperature of carbonization. Much research has been done on the chemical and physical characteristics and constituents. The outstanding property of the gas, from a commercial viewpoint, is its high calorific value. This opens the possibility of its use as an enriching agent for producer gas of low calorific value. It has been suggested recently, that polymerization of the gas from LT processes would produce marketable organic compounds, especially motor fuel. Further research is needed in this field.

Liquor: The aqueous distillate from LT tar is usually yellow in color when drawn off but turns red upon oxidation. Its reaction is acidic... [The constituents include:] hydrochloric acid, ammonium chloride, acetic acid, formic acid, acetaldehyde, and ketones, ethylamines, pyridines, and phenol, cresols, and xylenol...

Ammonium Sulfate: Ammonium sulfate is obtained by scrubbing the fuel gas with sulfuric acid as it emerges from the retort. The yield from LTC is considerable lower than that from HT carbonization. The yield varies with process and temperature used, the maximum yield being obtained at approximately 750° C (1382° F).

Ammonia also is recovered as ammonia sulfate solution which can be utilized in soda works or for other purposes...

Status of Industry in Various Countries ~ [ Not included here ]


Chapter 3

The Coals of Utah

[Not included here]



 
 

Chapter 4

Summary of Published Data

Types of Data: References may be classified in two groups, viz:

(1) General Information, covering (a) Physical, Chemical & Thermal Properties, (b) Petrographic Studies, (c) Coking Constituents, & (d) Briquetting

(2) LTC, covering (a) Technology as Applied to Utah Coals, & (b) Semi-coke & By-product Yields & Analyses

General Information ~  [Not included here]

Low Temperature Carbonization ~

The technology of LTC has been discussed at length by several investigators (# 381, 405, 407, 409, 479). They have pointed out the relation of the origin and the state of carbonization of coals in general to problems of LTC. High-oxygen or high-volatile coals similar to those of Utah have been experimented upon in an attempt to solve the problem of producing from them strong and marketable coke. Attempts have been made to satisfactorily explain why these high-volatile coals are generally non-coking. Also the effects of weathering or oxidation upon the coking properties has been investigated.

These studies have a direct application to the carbonization of Utah coals and other coals of the same class or rank. However, all of the essential facts concerning the reaction of coal to various carbonization techniques cannot be based logically upon generalizations, but must be determined by comprehensive studies made upon the coals in question.

Semi-Coke & Byproduct Yields & Analyses ~ [Not included here]

Relationship of Previous Work to this Investigation ~

The foregoing summary presents in brief form the most important items of information which are related to the problem of carbonizing coals at low temperatures.

The two primary objectives of this investigation were (1) the impartial and scientific selection of the most suitable processes for the LTC of Utah coals, and (2) a sound indication of the commercial feasibility for LTC in Utah. This information was to have been determined as completely as possible upon the basis of small-scale tests.

The following paragraphs review the major items of data which are paramount to the proper carrying-out of the work required by this investigation. Conclusions are drawn afterwards concerning the relationship of previous work to this study.

Part IV describes 101 processes for LC. These are divided into Major and Minor Processes according to the classification presented in Chapter 8. The Major Processes, numbering 18 in all, are the ones which are generally outstanding from the standpoint of technical and economic success and have come to the foreground during the past 10 years. For practical reasons, the most suitable processes have been selected from the Major Processes. Therefore, all available information must be secured for these processes with regard to their suitability to Utah coals, their construction and operating features, and other essential data. Also these data must be of recent date, since some of the early information published is no longer applicable due to changes which have been made in the processes.

As discussed in Chapter 2, the yield and quality of the carbonization products may be materially altered by carbonizing temperature and method of heating. Therefore, it is required to know the carbonizing temperature and method of retorting that will produce the most suitable semi-coke or smokeless fuel and that will also give the maximum economic returns from the sale of the byproducts.

The importance of a basic knowledge concerning the behavior of coal during carbonization has already been discussed (Chap. 2). Therefore, it is necessary to ascertain the characteristics of Utah coals during their transformation to semi-coke and to know the variations in the coking and swelling properties of these coals.

One of the major factors entering into the economic phase of this investigation, is the determination of the probable market values for the principal carbonization products. Therefore, the properties as well as the yields of the semi-coke, fuel gas, tar, and light oil must be known and their probable market values determined upon the basis of these data.

Summary: With the above considerations in mind, the following conclusions are drawn concerning the applicability of previously obtained data to this investigation. These conclusions are based upon published data only, and not upon the information which may be in the hands of private companies or individuals.

(1) The suitability of Utah coals has been investigated only with regard to the Karrick, Parr, Greene-Laucks, and McIntyre processes. Utah coals have been treated by at least to other processes, but reports of these tests have not been published. All but one of the above-named processes, i.e., the Karrick process, have been operated on a semi-commercial scale and have subsequently failed.

(2) No comparative tests have been made to determine the relative yield and quality of products obtained from a rotary retort versus a vertical retort, when using coals taken from the same samples and carbonized under the same conditions. These two retort types constitute the most generally used systems today.

(3) The optimum carbonizing temperatures have not been determined for any of the heating methods or carbonizing apparatus. The majority of the information published on Utah coal during the last 10 year concerns the Karrick process, and even here the economic feasibility is not clearly known since there has been no commercial plant in operation using this process.

(4) Very little work has been done to determine the market value of the tars, in fact very little is known about them except for the tar produced from the Karrick process using superheated steam.

(5) There are no data regarding the fundamental carbonizing properties for the commercially important Utah coals.


Part III

Laboratory Investigations & Carbonization Studies

Chapter 5

Introduction

Objectives ~

The two principal objectives of this part of the investigation were (1) determination of the effect of (a) carbonizing temperature in the range of 450° to 850° C (843° to 1562° F), (b) heating media, and (c) the two most generally used types of retorts for LTC, on the quantity and quality of semi-coke, fuel gas, and tar obtained from Utah coals, and (2) determine of the pertinent chemical and physical properties of Utah coals and their relation to the yields of carbonization products and the strengths of the semi-cokes.

These studies were necessary in order to determine the gas, semi-coke, and byproduct-making properties of Utah coals in accordance with the approved outline of investigation.

The apparatus and the procedures used for sampling, analyzing, testing, and carbonizing are described in Part VI of this report.

Selection of Coals for Testing ~ [ Not included here ]

"A study was required to determine the minimum number of coals that would represent the total range in the variations of the chemical constituents and the carbonizing properties of the 40 coals.

For the purposes of this study, a composite stratigraphic chart of the coal beds was prepared. This chart showed the locations of the various beds according to the vertical position they occupy in relation to the predominant strata of sandstone and other geological formations of the two principal coal-producing areas. Also shown were the relative positions of the same beds from one locality to another. Commercial mines were identified with their corresponding coal beds in order to establish a definite correlation between the mines and the tradenames of their coals.

In conjunction with the stratigraphic data, proximate and ultimate analyses for the many coals were obtained from the operators who had this information or from the US Bureau of Mines.

With the above data assembled in tabular form, and with the aid of the stratigraphic chart, seven coals were selected which are representative of the coals being produced from 40 mines both as to chemical composition, carbonizing properties, and their stratigraphic position. Results obtained with these coals should, therefore be applicable to all other coals from which the selected few were chosen.

Collecting & Testing of Samples ~

Chemical & Physical Tests: The usual proximate and ultimate analyses and calorimeter tests were made... Ash softening-temperatures were determined...

The softening and plastic properties of each coal were determined by the Agde-Damm dilatometer test. Other methods were investigated include Layng-Hawthorne’s version of the Foxwell test and the Davis plastometer test. The former method, which measures the resistance to flow of current of nitrogen gas through a bed of granular coal being heated slowly, has been found to give results which are not as accurate as those obtained by the Agde-Damm method. The Davis plastometer is designed for coking bituminous coals only and measures the resistance to turning of a stirrer offered by a bed of loose, granular coal being heated at a uniform rate. It is reported to give the most reliable and complete information over the plastic range... This test is not applicable to Utah coals which are in the main weakly-coking or non-coking. For these reasons, the Agde-Damm test was adopted because it provides valuable knowledge on the preplastic temperature range which cannot be obtained with the Davis plastometer and, also, because it is the most suitable for the plastic range of the less fusible coals such as the Utah coals.

The coking or agglutinating power of a coal is its ability to cement itself and inert material into a coherent mass upon carbonization (# 1102). Agglutinating values were determined by the Bureau of Mines method, except that a carbonizing temperature of 650° C (1202° F) and a sand-coal ratio of 8 to 1 were used instead of the usual temperature of 950° C (1742° F) and sand-coal rations from 20-25 to 1. These changes were necessary to produce a homogenous reading in the compression test. The compression machine applied the load at a constant rate and had a capacity of 25 kg.

There are several laboratory tests that have been devised to determine the readiness with which coals and cokes will ignite and maintain combustion. These may be grouped into three classes, (1) ignition temperature tests, (2) combustibility tests, and (3) reactivity tests. The first two terms apply to measurements of the rate of the reaction with oxygen or air, while reactivity applies to the measured rate of reaction with other gases or with liquid reagents.

The method most widely used in England to determine the combustible properties of coal and coke is the Critical Air Blast (CAB) test developed by the Northern Coke Research Committee. This test consists of igniting the coke and then determining the minimum air rate that will continue to keep the coke burning. This air rate, known as the Critical Air Blast, is expressed in cubic feet per minute, measured dry at 30" Hg and 60° F.

A study was made of the many test methods including the CAB test to determine the one most suitable for the purposes of this investigation. We were concerned only with ascertaining under uniform conditions, the relative ignition properties of the semi-cokes produced at each carbonizing temperature and with each type of retort and heating medium. The apparatus had to be readily built and simple to operate, and scientific refinements both as to apparatus and operating technique were not considered to be of sufficient importance to warrant their adoption. The values obtained by the various test methods, which are usually of complicated and special design, vary for the same combustible according to the apparatus and technique used, the size of the material and other conditions.

For these reasons, an inexpensive and easily operated apparatus was built which gave results from duplicate tests that checked within 5° C. The method was based on the reaction between sized combustible and air, heat being slowly applied and at a given rate to the fuel, and air being admitted under constant conditions. It was found to be entirely suitable for the work at hand, and was used not only for the coals and the semi-cokes produced in our laboratories, but was also applied to the semi-cokes manufactured by various commercial LTC companies...

Numerous chemical and physical tests could have been made with these coals in addition to those named above. The forms of sulfur, the composition of the ash, the amounts of solid and oily bitumens as determined by extraction with benzene, and the percentages of alpha, beta and gamma compounds, also ulmins, as determined by extraction with pyridine and chloroform, could have been made and much valuable data obtained. However, since these tests have no immediate bearing upon the problem of selecting the most suitable processes and determining the economics of LTC of Utah coals, they also were not undertaken.

Description & Properties of Coals Tested ~

Classification by Rank & Grade: The position a coal occupies in the serried from peat to anthracite is known as its rank. Increase in rank in coal is due to various geological factors which are not discussed here...

The chemical properties of the coals are summarized in Table 2 [Not included:  Coal # ~ Analysis, %, Proximate & Ultimate Moisture, Volatile Matter, Fixed Carbon, Ash, H, C, N, O, S, Btu/lb, Ash Softening Temp. ~ Coal Classification (i.e., high-volatile bituminous, &c).

To summarize, the commercially important coals of Utah may be either of the high-volatile A or high-volatile B bituminous groups, and the sub-bituminous A group. By far the greater majority of bituminous coals are of the high-volatile B group. The bituminous coals do not disintegrate to any considerable extent upon exposure to the weather, but the sub-bituminous coals slack very readily.

Chemical Properties: [Not included here]


Chapter 6

Results of Carbonization Tests with Experimental Plant

The carbonization tests were made according to the procedure described in Part VI of this report.

A cylindrical, vertical retort of steel, 5" in diameter and 6 ft high, was operated with external heating at temperatures beginning with 450° C and increasing in 100 increments to 850° C inclusive. This temperature range was selected to cover the ranges used in commercial practice for carbonization at both low and medium temperatures. All of the principal medium-temperature installations employ vertical, static, and externally-heated retorts or ovens. Internal heating with superheated steam was conducted only at 550° and 650° C in order to conform to the temperature range suggested in certain proposed processes. Carbonization with superheated steam at 450° C or at temperatures higher than 650° C is not practicable.

Also employed was a cylindrical, horizontal, rotating retort constructed of steel. It was 10" in diameter and 3 ft 10" long. External heating was carried out at 450°, 550°, and 650° C to reproduce the most widely used temperatures in commercial rotary retorts. Higher temperatures are not used in commercial practice because they cause serious warping of the retort and operating difficulties. One test was made with superheated steam admitted internally to the charge. Problems arose which could be solved only by the installation of a specially designed retort and auxiliary equipment. Further tests were not deemed necessary in view of the fact that all available data were in hand for the only internally-heated rotary process (Suncole) in commercial use.

The foregoing units were not patterned after any specific process for distilling coal. Rather, they were designed to represent, insofar as possible, the fundamental principles embodied in all processes which use static and rotating retorts.

Units of Measurements & Method of Stating Results: US gallons (231 cu in) and short tons (2000 lb) are used throughout this report.

The yields of carbonization products are based on coal as carbonized.

Coke: The yield is given in percent of coal as carbonized, without correction for a very small amount of moisture from the atmosphere during 24-hour period when coke was being tested and prepared for chemical analysis.

Gas: Yield, specific gravity, composition by volume, and gross heating value are reported as stripped for light oil, ammonia and hydrogen sulfide, and saturated with water vapor at 60° F and 30" Hg. Specific gravities were calculated from analyses.

Tar: The yield and properties of tar are given on the dry basis. The yield does not include the light oil stripped from the gas but does include any light oil condensing with the tar.

Light Oil: The yield and properties of light oil are given on the dry basis. Unless otherwise stated the term "light oil" refers to the crude product stripped from the gas.

Ammonium Sulfate: The yield is given in pounds per ton of coal carbonized and includes total free and fixed ammonia.

Liquor: The liquor includes the fixed ammonia and dry, free ammonia absorbed by it.

Tables & Figures ~ [Most are not included here]

The following discussions refer to Tables # 3 to 13 inclusive and to Figures # 1 to 64 inclusive...

Table 3 ~ Yields of Carbonization Products, As-Carbonized Basis
Table 4 ~ Analysis of Semi-Coke, Dry Basis (Coal # 1)
Table 10 ~ Analysis of Dry, Crude Tar & Neutral Oil (Coal # 1)
Table 11 ~ Distillation of Dry Crude Tar & Neutral Oil (Coal # 1)
Table 12 ~ Estimated Yields of Products
Table 13 ~ Value of Carbonization Products (Semi-Coke, Gas, Tar, Light Oil)
Table 18 ~ Comparison of Analysis & Heating Value of Natural Gas & LTC Gas

Figure 1 ~ Yields from Coal # 1 (Amm. Sulf., Light Oil, Tar, Semi-Coke)
Fig. 8 ~ Comparison of Yields of Carbonization Products
Fig. 36 ~ Physical Constants of Gas/Carbonizing Temperature (Coal # 1)
Fig. 43 ~ Composition of Gas, Vertical Retort (Coal # 1)
Fig. 50 ~ Composition of Gas, Rotary Retort (Coal # 1)
Fig. 53 ~ Distillation of Tars (Coal # 1)
Fig. 60 ~ Comparison of Gravity & % Tar Acids of Tars from Different LTC Methods
Fig. 64 ~ Thermal Distribution fo Products @ Various Carbonization Temperatures

Fig. 86 ~ Layout of Davidson LT Retorting Plant (500 tons/day)
Fig. 87 ~ Hayes Retort
Fig. 88 ~ Hayes Process Plant (500 tons/day)
Fig. 97 ~ Coalite Retort, Vertical Section
Fig. 98 ~ Coalite Plant Layout
Fig. 99 ~ Hird Retort
Fig. 100 ~ Derby-Horner Carbonizing Unit
Fig. 104 ~ Analysis of Tar Products, NFC Process
Fig. 106 ~ National Carbonizing Co, Mansfield Plant
Fig. 107 ~ Rexco Plant Diagram
Fig. 108 ~ Gibbons/Cellan-Jones Battery Discharge
Fig. 109 ~ Gibbons/Cellan-Jones Ovens Battery
Fig. 110 ~ Gibbons/Cellan-Jones Ovens, Top
Fig. 112 ~ Proposed Gibbons/Cellan-Jones Battery
Fig. 113 ~ Lecocq Semi-Coke Oven

Fig. A-1 ~ Agde-Damm Plasticity Apparatus
Fig. A-3 ~ LTC Schematic Layout, Static External Heating
Fig. A-4 ~ LTC Schematic Layout, Static Internal Heating
Fig. A-8 ~ Plant Operating Curves (Vertical Retort, Internal Superheated Steam)

Yields of Carbonization Products ~

The yields and qualities of carbonization products obtained are given in Tables 3 to 11, inclusive. The dominant influence of carbonizing temperature, heating method, and equipment is shown clearly in Figures # 1 to 64.

Figures 1 to 7 inclusive show the yields of semi-coke, tar, gas, light oil, and ammonium sulfate obtained from the individual coals. Figure 8 presents the yields of semi-coke, tar and gas produced at each of the carbonizing temperatures and for each method of carbonization. The coals are arranged from left to right in ascending yield of semi-coke...

Semi-Coke: The yield of semi-coke decreases gradually with rising carbonizing temperature, the change being most noticeable for the product from the vertical retort using external heating from 450° to 550° C... Characteristic of all the coals is that the yield of semi-coke is consistently greater with the vertical retort and internal heating, followed next by the yield from the vertical retort externally heated, and the lowest yield being from the rotary externally-heated retort.

Tar: From the rotary retort is produced the greatest yield of tar, which most generally remains constant throughout the range from 450° to 650° C. As with the yield of semi-coke, the vertical externally-heated retort yields tar in amount between that from the rotary and the internally-heated vertical retort. It is noted that the yield is always low at 450° C and increases rapidly to 550° C where it remains generally constant throughout the range to 850° C... Generally, a slight reduction of yield takes place after 550° C, but at 750° C in almost every case the yield increases and sometimes surpasses slightly the yield at 550° C... The internally-heated vertical retort always gives the least amount of tar of any of the methods of carbonization...

Gas: In line with the yields of other products, the yield of gas from the vertical externally-heated retort is less than the yield from the rotary but is greater than the yield from the internally-heated vertical retort. In [almost] every case... the yield increases at almost a constant rate throughout the temperature range...

Light Oil: The yield of light oil from the vertical externally-heated retort is greatest at 650° C [in most cases]. For the other carbonizing methods, the yield is always slightly less, being generally in the order of the vertical internally-heated retort and then the rotary retort.

Ammonium Sulfate: The yield with the vertical, externally-heated retort is greatest at 750° to 850° C [depending on the coal type]. The rotary retort produces the least amount of ammonium sulfate and generally the yield with steam as a heating medium is between that obtained with the rotary retort and the vertical externally-heated retort.

Quality of Products ~

Semi-Cokes: The change in chemical composition and physical properties of the semi-cokes with increasing carbonizing temperature and the different carbonizing methods is shown in Tables 4 to 8 inclusive and Figure 9 to 35. It is of particular interest to note that the heating value on the dry basis of the bituminous semi-cokes (Table 4) is slightly less than the heating value of the corresponding raw coal (Table 2), but the sub-bituminous semi-cokes all have heating values greater than that of the raw coal. In general, the heating value of the semi-cokes decreases with increase of carbonizing temperature.

Mechanical Strength: The mechanical strength or stability of the semi-coke produced in the vertical externally-heated retort [usually] increases slightly with increasing temperature above 550° C. In the temperature range from 550° to 650° C, the semi-coke from internal heating with the vertical retort and with the rotary retort vary within wide limits being as much as 25%.

The stability of the semi-coke produced with superheated steam [usually] is greater than when produced at 650° C than at 550° C. The increase in each case is rather marked.

The stability of the semi-coke from the rotary retort is less than for the semi-coke from the vertical retort externally-heated, and is generally less than that produced with superheated steam...

By inspection of semi-coke photographs (Figs. # 12-35) the marked difference in the vertical and rotary semi-cokes is readily apparent, in that the fuel from the latter retort is rounded on the edges due to the tumbling of the material in the retort...

The photographs of the semi-cokes produced from blended coals (Figs. # 33-34) show that considerable agglomeration took place throughout the charge... Greater stability is evident in most cases than with the semi-cokes resulting from the standard charge. However, it is to be noted that large percentages of the coking coal are required to effect this strength.

A comparison of the semi-coke produced from [various tests] indicates that rapid heating is detrimental to agglomeration, since there was less large-sized semi-coke and the stability was less for the rapidly-heated material. Further proof of this marked tendency is presented in Tables 6 and 8 for semi-cokes produced by rapid heating in the vertical retort and by slow and rapid heating in the rotary retort respectively.

Ignition Temperature: The ignition temperatures of the semi-cokes increase with rise of oxidizing temperature. The ignition temperature is lowest for the semi-cokes produced with steam, the rotary semi-cokes are next highest, and the vertical, externally-heated product has the highest. It is interesting to note that up to a carbonizing temperature of 650° C, the ignition temperature of all the semi-cokes are below that of the raw coal with the exception of the semi-coke from the vertical externally-heated retort at 650° C.

The ignition temperatures of the sub-bituminous semi-cokes are in general much lower than the corresponding bituminous semi-cokes even though the raw coal ignition temperatures for both ranks of coal are practically the same. Noteworthy is the fact that at all carbonizing temperatures and for all three types of carbonization, the ignition temperature for the semi-cokes produced from the sub-bituminous coal are lower than that of the raw coal. As with the bituminous coals the semi-cokes produced with steam have the lowest ignition temperature, but at carbonizing temperatures of 550° and 650° C, the semi-cokes from the rotary have higher ignition temperatures than those from the vertical externally-heated retort which is in opposite order to the results obtained with the bituminous coals.

Referring to Table 4, an interesting point of note is the fact that the semi-coke produced with superheated steam has the lowest ignition temperature and also has the highest volatile content of the semi-cokes at each of the corresponding temperatures of carbonization.

Ignition temperature tests made upon the semi-cokes from the blended coals indicated in general that these semi-cokes have an ignition temperature approximately 30° C below those produced from the corresponding coals alone at the same carbonizing temperature.

Gases: Table # 9 gives the physical and chemical properties of the gases, and Figures # 36-52 illustrate how these properties vary with carbonizing temperature and carbonizing method.

Figures # 36-42 show that the Btu recovered in gas per pound of coal carbonized increases at a slightly slower rate at the higher carbonizing temperatures. The Btu per cubic foot and the specific gravity vary inversely with the carbonizing temperature. Figures # 43-49 show that for gases produced with the vertical retort, the percentages of hydrogen and carbon monoxide increase with increasing temperature, that the illuminants, the methane and the ethane decrease with rising temperature, and that the carbon dioxide tends to be maximum at or near 650° C...

Tars: Table # 10, analysis of the dry tar and neutral oil; Figs.#  53-59 show the variation of percentages of tar fractions with carbonizing temperature and for the 3 methods of carbonization used in the laboratory. Fig. #  60 shows the variation of the gravities and percentages of tar acids with different carbonizing methods as well as for the several carbonizing temperatures. Figs. 61 presents a comparison of viscosities of the tars produced by different carbonizing methods. Fig. 62 compares the distillation curves for the tar and neutral oil.

Apparently the tars produced by external heating in both retorts have approximately the same viscosity at the same temperature of carbonization except at 450° C. The viscosities of the tars produced with steam, however, are much greater particularly at 650° C than those from the other carbonizing methods at the same temperatures...

According to previous studies (# 1316) the specific gravity of low temperature tars increases with rise in carbonizing temperature. Table # 10 shows that this is generally true for the tars obtained in this investigation, particularly for the steam-produced tars... All the tars produced with superheated steam exhibit slightly higher specific gravities than those from externally-heated retorts...

The sulfur content of the tars is much lower than that reported by Gentry (# 519).

The percentage of bottoms, sediment, and water (BSW) for the rotary crude tars is considerably greater than for the tars from the vertical retort. Undoubtedly a substantial reduction could be effected in commercial practice by the use of appropriate cyclone extractors, since the greater portion of this material is semi-coke dust.

All solidification temperatures of the crude tars (Table # 10) are about the same with the exception of those produced from bituminous coals at 450° C in the vertical externally-heated retort. The latter tars solidify at a much lower temperature, indicating that they contain a lower percentage of waxy constituents...

The tar acid content was generally higher than for most tars reported by other investigators and summarized by Gentry (# 519), who shows that the yield of tar acids increases with increasing oxygen content of the coal...

The oil remaining after removal of the tar acids and bases, is known as neutral oil. Neutral oil recovered from the tars investigated contained an average of 4.5% unsaturated compounds.

Data from Universal Oil Products Company: "Based upon the above data and an average crude tar yield for the bituminous coals of 30 gallons per ton, it is evident that cracking the crude tar... to a liquid residuum will give 6 to 7.2 gallons of gasoline per ton of coal, while cracking to coke residue yields 10.5 to 12 gallons. These gasolines will, however, contain 10 to 15% tar acids so that the tar acid-free gasoline yields then become about 5.4 to 6.5 and 9.5 to 10.8 gallons respectively.. Similarly the subbituminous coal tar will yield about 2.7 to 3.3 and 4.8 to 5.4 gallons per ton of coal.

Cracking the dephenolated tar from the bituminous coals to a liquid residuum gives a yield ranging from 4.5 to 8.8 gallons of gasoline per ton of coal, based upon the crude tar having an average neutral oil content of 60%. On the same basis, cracking of coke residue gives from 8.1 to 11.2 gallons. The subbituminous coal tar, on the basis of 55% neutral oil will yield about 5.1 gallons per ton of coal by cracking liquid residuum and 5.9 gallons by cracking to coke.

Data from Reilly Tar & Chemical Corporation: [Not included here]
Data from The Barrett Company: [Not included here]
Tests on Crude Tar: [Not included here]
Distillation to 350 C 2-Qt Still: [Not included here]
Distillate to 350 C: [Not included here]
Tar Acids & Extracted Oil from Distillate to 350 C: [Not included here]
Light Oil: [Not included here]

Summary ~

Thermal Distribution of Carbonization Products: Figure # 64 shows the distribution of the carbonization products in heat equivalents for each of the coals for the different temperatures and methods of carbonization. The chart clearly shows the decrease of total heat contained in the semi-coke with temperature rise and the corresponding increase in total heat contained in the gas.

The percentage of the total heat units in the raw coal remaining in the semi-coke is less with the rotary than with the vertical retort externally heated, while the Btu in the gas and the tar on a percentage basis are greater with the rotary than with the latter retort. Superheated steam in the vertical retort produces semi-coke containing heat units on the same basis greater in every case than with the rotary and vertical externally-heated retorts at the same carbonizing temperatures. Also for superheated steam, the percentage of heat units contained in the gas is always lower than for the gas from the other retorts.

The total heat in the light oil per pound of coal is practically constant.

Effect of Carbonizing Temperature: The general effect of increasing the carbonizing temperature is to increase the yield of gas, ammonium sulfate, and to a slight extent the tar above 550° C. At the same time, the heating value of the gas per cubic foot and its specific gravity is decreased. The tar yield increases with the temperature from 450° to 550° C and then tends to remain more or less constant to 850° C. Higher carbonizing temperatures increase the proportion of the lower-boiling fractions. The yield of light oil reaches a maximum at 650° C for most of the coals tested. The yield and heating value of the semi-coke decrease with rising carbonizing temperature .The yield of light oil attains a maximum at 650° C for most of the coals tested. The ignition temperature of the semi-coke increases with carbonizing temperature, the lower temperature giving ignition points below that of the raw coal.

Effect of Blending: The yield and quality of the carbonization products made from blended coals are characteristic of the results obtained with the predominating coal used in blends. That is, a blend containing 80% of Coal #6 will give products very similar in yield and quality to those obtained at the same carbonizing temperature with Coal 6 alone.

Effect of Retorts & Heating Media: The effect of retorts and heating media upon the yield and quality of the carbonization products is presented below. In all cases, comparisons are based on the same carbonizing temperatures for each item, and also upon the results of this investigation conducted in the manner described in Part VI.

Rotary Retort, External Heating (Ave. heating rate 2° C/min): Minimum yield of semi-coke having the lowest mechanical strength and an ignition temperature between that of the vertical retort semi-cokes using external and internal heating. Maximum yield of tar. Tar has the highest percentage of bottoms and sediment, which can be removed by special equipment as part of the carbonizing plant. Tars are not considerably different in quantity from vertical retort, externally heated. Maximum yield of gas having heating value in general about the same as for the externally-heated vertical retort. Minimum yield of light oil and ammonium sulfate. Maximum degree of carbonization. Semi-cokes have lowest volatile contents. 450° C semi-cokes are smokeless. Secondary decomposition of volatile products is a maximum, but products are characteristically those of LTC.

Vertical Retort, External Heating (Ave. heating rate 2.1° C/min.): Semi-coke has the greatest mechanical strength. The yield between that of rotary and superheated steam-produced tars. Quality is about the same as that of the rotary retort tar. Gas yield less than that for the rotary retort. Maximum yield of light oil and ammonium sulfate. Medium degree of carbonization. Volatile contents of semi-cokes higher than for rotary products. 450° C semi-cokes smoke. Secondary decomposition of volatile products takes place to a lower degree than for the rotary retort.

Vertical Retort, Internal Heating with Superheated Steam (Ave. heating rate 2.8° C/min.): Maximum yield of semi-coke with mechanical strength between that of the semi-cokes produced by the externally-heated retorts. Ignition temperature lowest. Minimum yield of tar having highest possible specific gravity and viscosity. Remaining properties about the same as for the other tars. Minimum yield of gas having highest heating value. Illuminants and ethane are higher, while carbon dioxide, hydrogen, and methane are generally lower than for externally-heated retort gases. Medium yield of light oil and ammonium sulfate. Minimum degree of carbonization. Semi-cokes have highest volatile contents but produce no smoke. No 450° C semi-cokes made. Little if any secondary decomposition of volatile products occurs due to sweeping action of steam.

Table # 13 translates into terms of dollars and cents the combined effects of carbonizing temperatures and methods upon the yields of products from each of the seven coals. This table is based upon conservative unit values and also upon the assumption that each of the products have the same values regardless of the carbonizing temperature or method employed. Such an assumption is not without foundation, since LTC has not been developed in Utah to the advanced stage when prices may be accurately determined for each of the major products upon the bases of variation in quality.

It is apparent that, in general, the lower carbonizing temperatures yield products having the maximum total economic worth, since the yield of semi-coke decreases with increasing carbonizing temperatures. The rotary retort provides the maximum economic returns of all the methods, chiefly because it produces the maximum yield of tar which commands a higher price per ton...

With rapid heating little variation can be detected in the yield of semi-coke from that obtained with slow heating. The rapid heating is, however, definitely detrimental to the mechanical strength or stability of the semi-coke. The gas yield is apparently little affected by the rate of heating. Rapid heating tends to increase the tar yield slightly, ranging from 0.8 to 1.1% of coal by weight. It must be observed in evaluating this comparison of slow and rapid heating that because of the limitations of the equipment, the rapid heating of the coal charge occurred only in the carbonizing temperature range up to about 425° C and not throughout the full range to 650° C.


Chapter 7

Relation of Chemical & Physical Tests to Yields of Carbonization Prodcuts & Strengths

[Not included here]


Chapter 8

Processes & Limiting Factors Entering Into Their Selection

Retorts & Heating Methods ~

The following paragraphs present the general advantages and disadvantages of the most common types of retorts and heating methods. There are, of course, special systems for carbonization at low temperatures which cannot be analyzed in general terms.

Vertical Retorts: Vertical retorts produce less breeze from non-coking coals than do rotary retorts, because the lumps are not broken by the tumbling action induced by rotation. Continuous operation tends toward a conservation of heat and labor and an increased life of the retort. Intermittent operation may have simplified mechanical arrangements: examination of the retort interior is more easily accomplished, and the charge is under more direct control.

Construction and operating costs are said to be higher than for rotary retorts. With strongly coking coals, discharge of the carbonized fuel from intermittent vertical retorts is more difficult due to the expansion of low-temperature semi-coke and its tendency to stick to the retort walls. This, however, is not the case with the non-coking coals of Utah, which ordinarily shrink sufficiently to permit easy discharge. Even the best Utah coking coal does not stick to the retort, but may give a little difficulty during discharge, especially for the lower carbonizing temperatures.

Horizontal Rotary Retorts: Costs of construction of horizontal rotary retorts are generally lower than those for vertical retorts. They are continuous in operation and have low maintenance costs. They permit bulk treatment of the charge, require less handling and lowers the cost of processing per unit of throughput. The constant tumbling of the charge during the carbonization period assists heat transfer materially, heats the charge uniformly, and maintains an even volatile content in the semi-coke.

The semi-coke is weaker than that produced in vertical retorts; more breeze is produced which must be briquetted for the market. A quantity of dust is raised in the rotary retort which is carried over into the tar main by the volatiles. Special dust-catchers must be used to eliminate this problem.

Moreover, it may be difficult to recommence operations in the event of an interruption or breakdown.

Modified By-Product Coke Ovens: it was originally thought that a satisfactory semi-coke could not be produced economically in the by-product coke oven system. However, in recent years considerable work along this line has been done particularly in England. As a result, there are at least three processes which have been independently developed and tried with apparent success. Such methods require coking coals or blends of strongly-coking and non-coking coals.

The most important modification is the decreasing of the oven width to permit complete and uniform carbonization at the lower temperatures, and also to allow more rapid carbonization of the charge.

Internal vs External Heating: Externally-heated retorts are those in which coal is carbonized ion a gas-tight chamber, the entire heat for carbonization being passed through the retort wall. Solid, liquid or gaseous fuel is burned either in a chamber which surrounds the retort proper or in a series of heating cells built on the outside of the retort wall.

Internally-heated retorts are those in which a gaseous heating medium is circulated through the retort in intimate contact with the coal. The heating medium may be either superheated steam or other inert gas, or a combination of the two. The inert gas may be generated from the combustion of solid, liquid or gaseous fuel either inside the retort or in a chamber externally thereto.

In order to produce a uniformly treated residual fuel in externally-heated retorts, coal must be carbonized in thin layers. Thus, a large number of retorts are required for a plant of commercial size, and they must be specially arranged so as to make an installation which is compact and occupies a minimum of ground space. However, it is comparatively simple to obtain and to recover the volatilized products from such retorts.

Internal heating facilitates the transfer of heat to the coal, increases the heating efficiency, and educes secondary decomposition to a minimum by the sweeping action of the inert gas. However, when producer gas or products of combustion are used, the fuel gas distilled form the coal is diluted and consequently, the heating value of the combined mixture is very low. Furthermore, the capacity of the condensing system must be of sufficient size to handle the large volume of gas required for carbonization.

Superheated Steam: The primary object of steam distillation in the carbonization of coal is to remove quickly the volatile products from the retort before they may undergo secondary decomposition. Superheated steam also has a relatively high specific heat, in comparison to other inert gases. The heating value of the fuel gas, moreover, is not lowered when steam is used as the distilling medium.

However, unless steam can be obtained as a waste product from some other operation, it is expensive to generate and to superheat. Additional equipment is also required to control the steam and to handle it after condensation. Unless special apparatus are provided, the latent heat of the steam is lost during condensation and thus the heat requirements are considerably higher than for other processes.

Coal-Oil Mixture Processes: The carbonization of coal-oil mixtures was first developed about 1918 but was abandoned. About 1930 the method was revived and has received considerable attention, especially in Britain. The coal-oil mixture is a paste of finely divided coal and crude oil. There are two general types of treatment with many minor variations. The first consists of carbonization at atmospheric pressure and may be carried out at different temperatures. The second type involves carbonization under pressures which may be as high as 200 to 300 lb sq in and at a temperature of 570° F or above.

The residual mass ranges from a thick liquid or "colloidal" fuel to a semi-coke of fair quality. It is claimed that the yield of light oil is increased but there are little authoritative data on actual yields or on fractionation tests and the quality of the products.

Limiting Factors in Selection of Processes ~

According to Brownlie, there are at least 800 processes which have been proposed in 30 odd years for LTC. The bibliography in Part VIII of this report lists 101 individual processes that have either been originated or developed in many countries throughout the world.

There are certain practical considerations in the examinations of these methods that immediately limit the total number from which a selection may be made. The examination may be divided into two parts, viz: routine examination and detailed examination.

Routine examination involves the securing of additional data through correspondence and from the carbonization of Utah coals by the companies themselves. In this manner, up-to-date technical data may be obtained...

General conclusions concerning the examination of the 101 processes are given below.

(1) Many of the processes have not gained attention for several years because they have proved to be unsuccessful from the technical and/or economical standpoints, or because of financial difficulties within the organizations. Hence, no companies are in existence that are promoting these methods.

(2) Some of the processes are in the development stage, and have not yet been incorporated in either a large-scale experimental or commercial plant. Hence, there is no sound basis upon which the technical and economic potentialities may be determined, despite the claims by some of the controlling individuals and companies that this is not the case. Usually the amount of available information is very meager. However, in a few cases there appeared to be a justification for considering these processes form the standpoint of tests which have been made with Utah coals, or because comparisons could be drawn between the results of commercial installations using similar methods, and the results of the tests which the foundation conducted.

(3) Several processes are now being investigated in semi-commercial or commercial installations. For some of these methods, detailed data were obtained. However, this information was not available for many of them because data are not forthcoming. Tests could not be conducted with Utah coals in many cases because the companies did not have the required facilities or were not interested in promoting their methods in Utah, or other parts of the country.

(4) Finally, the required data for a dew of the processes could not be obtained. The general possibilities of these methods, however, were determined by studies conducted by the Foundation.

Classification of Processes: The above factors brought about a material reduction in the number of processes from which the selection was made. These processes are herein designated as the "Major Processes" and include, (1) processes that are now being applied commercially, (2) processes that have been used commercially and are still being exploited for commercial purposes, (3) processes that are now in the pilot-plant stage which are or may be suitable to Utah coals, (50 processes for which the required technical and economic data could be obtained through the cooperation of the companies involved, and (6) processes for which tests could be made with Utah coals.

Contained in the group designated as the "Minor Processes" are the remaining methods that are not included by the descriptions given for the Major Processes.

This method of classification is presented for the purpose of this investigation only, and is not intended to apply for coals other than those of Utah or for other localities. Future developments may justify rearrangement of processes within these groups.


Chapter 9

Minor Processes

[Note: This chapter has been condensed to titles and references ]

Reviews of Minor Processes are presented in the following pages. The information was secured from all available sources and is condensed in brief form to give only the most pertinent data. Details may be secured from the referenced material listed in the bibliography. Attention is called to the general similarity in the basic design and operating principles for each type of carbonizing method.

Plant capacities, carbonization yields, and economic data are reported in US units.

Horizontal Externally-Heated Stationary Retorts ~

Bonnevie (# 1138) ~ Burney (# 1142) ~ Chown (# 1153) ~ Fellner-Ziegler (# 1164) ~ McIntire (# 1199) ~ Richards-Pringle (# 1223) ~ Summers (# 1235)

Horizontal Externally-Heated Rotary Retorts ~

Bituminoil (# 1136) ~ Dobbelstein (# 1160) ~ Fusion (# 1167) ~ KSG (# 1185) ~ Mequin (# 1202) ~ Raffloer (# 1220) ~ Sheffield & Lloyd (# 1229, 1196) ~ Thyssen (# 1241)

Horizontal Internally-Heated Retorts ~

Holford (# 1181) ~ Morgan (# 1209) ~ Pehrson (# 1213) ~ Reed-Lamie (# 1221) ~ Sauerbrey (# 1227)

Vertical Externally-Heated Stationary Retorts ~

Brennstoff-Technik (# 1141) ~ Berg (# 1135) ~ Bowing (# 1140) ~ Carbolux (# 1147) ~ Carlton (# 1149) ~ Crozier (# 1155) ~ Fuel Res. Board (# 1166) ~ Holcobami (# 1180) ~ Illingworth (# 1184) ~ Krupp-Lurgi (# 1191) ~ Otto (# 1211) ~ White (# 1250)

Vertical Internally-Heated Stationary Retorts ~

Davies (# 1157) ~ Dual Gas (Devonian or  Jenson) (# 1161) ~ Haken (# 1173) ~ Hood-Odell (# 1183) ~ Kolergas (# 1189) ~ Lamplough (# 1192) ~ McEwen-Runge (# 1198) ~ Midland (# 1204) ~ Pintsch (# 1215) ~ Plauson (# 1218) ~ Seidenschnur-Pape (# 1228) ~ Sutcliffe-Evans (# 1237) ~ Turner (# 1247)

Coal-Oil Mixture Processes ~

Bluemner (# 1137) ~ Carbonol (# 1148) ~ Cranston (# 1154) ~ Dvorkovitz (# 1162) ~ Greenstreet (# 1172) ~ Knowles (# 1188) ~ Lewis (# 1195) ~ Meiro (1203) ~ Mondello (# 1207) ~ Ryan (# 1225) ~ Stephenson (# 1231) ~ Strevens (# 1233) ~ Struban (# 1234).

Producer-Type Processes ~

Bussey (# 1143) ~ Hanl (# 1174) ~ Maclaurin (# 1200) ~ Modified Mond (# 1205)

Miscellaneous Processes ~

Ab-Der-Halden (# 1133) ~ Babcock (# 1134) ~ Bostaph (# 1139) ~ Carburite (Delkescamp) (# 1158) ~ Eesti-Patendi (# 1163) ~ Freeman (# 1165) ~ Geissen (# 1168) ~ Greene-Laucks (# 1171) ~ Hereng (# 1177) ~ Hinselmann (# 1178) ~ Honigman-Bartling (# 1182) ~ Moore (# 1208) ~ Parr (# 1212) ~ Piron-Caracristi (# 1216) ~ Plassman (# 1217) ~ Prudhomme (# 1219) ~ Roser (# 1224) ~ Salermo (# 1226) ~ Stevens (# 1232) ~ Thermax (# 1238) ~ Trentha (# 1245)


Chapter 10

Major Processes

Horizontal Externally-Heated, Rotary Retorts ~

Davidson (# 1156)

Figure 86 ~ Davidson LTC Plant

Hayes (# 1176) ~  General: Early work on the Hayes LT Process was started in 1926 when the first patent was issued to Charles Hayes. Several patents have been issued since that time so that now the process is well covered. The Object of the Hayes process is to increase the value of slack bituminous coal, and at the same time to produce a solid smokeless fuel suitable for domestic use.

Figure 87 ~ Hayes Retort
Figure 88 ~ Hayes LTC Plant (500 tons/day)

Commercial Plants: The first commercial unit was placed in operation in 1928 at Moundsville, WV and is apparently the only one ever constructed. It was built by the Coal Distillation Co of WV.

This plant was capable of treating 50 tons of coal per day and produced semi-coke and briquettes which were sold as domestic fuel... The plant and the Ben Franklin mine which supplied it were inundated by the Ohio River Flood in 1936...

Retort: The Hayes plant at Moundsville used an alloy-steel tube or retort 17 inches inside diameter by 20 ft long (Fig. 87). This tube was placed in a furnace setting and supported by rollers at each end. Stationary feed and discharge castings were located at the opposite ends of the retort and were connected to it by special packing-rings. The tube was rotated in one direction at one and a half rpm.

Within the retort there was a specially constructed screw conveyer. This screw was 16" outside diameter with 12" pitch flights. The flights were hard surfaced on the outside edge to reduce wear to a minimum. The bearings supporting the screw were set one-half inch below the center line of the retort, thereby allowing the screw to rest on the bottom of the retort throughout its entire length. The screw was driven by a train of gears which gave it a progressive oscillating motion. The motion was such that the screw moved the coal towards the discharge end of the retort a given distance when rotating in one direction, and on the reverse oscillation the coal was returned a distance somewhat less than the forward movement. Due to this forward and backward motion the coal had a theoretical travel of 220 ft in passing through the length of the retort. Not only did this oscillating motion keep the retort wall free of adhering particles of coal, but it also increased the heat-transfer rate to the retort charge by keeping the coal in motion. Every particle of coal was repeatedly brought into contact with the hot retort walls and carbonization was completed in about 20 minutes.

A new installation would use a screw 20" in diameter and of greater length. The coal would be run through the tube at a higher speed than before, but the length of time the coal was in the tube would be the same or perhaps even less. A thin wall rolled tube would be used to increase the rate of heat transmission. The gear reversing mechanism would be eliminated; driving of the screws would be accomplished with a reversing motor.

After operating approximately 45 days it was found advisable to stop a retort to clean a deposit of hard carbon which gradually built up at several points on the interior. The cleaning of retorts was one of the regular duties of operation, accomplished with comparative ease.

Seven of these retorts were located in a battery type of furnace and each retort was entirely independent in its operation of the other six. Removable one-piece covers formed the top of the furnace and any retort could be removed for inspection or cleaning without interfering with the setting or the operation of the others. The seven reversing gears were driven from a common line shaft.

Heating Method: Each retort was heated externally by means of a gas burner located on the side of the furnace. All the firing was done in a combustion chamber located underneath the feed end of the retort. The hot gases of combustion, after passing through a baffle forming the top of the combustion chamber, passed around the outside of the retort to the waste-gas flue at the discharge end of the retorts.

Temperature & Heat Requirements: A furnace temperature of about 800° C (1470° F) was maintained in the combustion chamber at the feed end of the retort by automatic control. This produced a furnace temperature of about 650° C (1200° F) at the discharge end of the retort. These temperatures may be varied to suit both the type of coal treated and the quality of the char or semi-coke desired.

The heat required for carbonization was approximately 1100 Btu per pound of coal.

Coal Used: [Not included here]

Coal & Coke Handling: Coal was fed to each of the retorts from an overhead bin by a screw feeder located on the feed end casting. The rate of feed was from 550 to 650 lb/hr for each retort.

The char or semi-coke was discharged from the retorts into a collecting conveyer which ran the entire width of the retort setting. From this conveyer the char dropped into a quenching conveyer where it was quenched and partially cooled by water sprays, and then it was discharged through a rotary-seal valve into the char-conveyer.

A roller-type briquette press operating at 5000 lb pressure was used for compressing the LT coke into briquettes. Petroleum pitch was used as a binder.

A layout for a 500 ton/day plant using the Hayes process is reproduced in Fig. 88.

Performance: It is reported that during its operating period of several years, the plant demonstrated a complete success in carbonizing bituminous coals.

Properties of Semi-Coke: [Not included here]

Suitability to Utah Coals: Tests with Utah coals could not be made with the Hayes process since the Moundsville plant is inoperative, and other facilities are no longer available. However, according to the information received, the Moundsville installation "demonstrated a complete success in carbonizing bituminous coal of all descriptions. There is, therefore, no doubt that Utah coal can be treated by this process as successfully as any other. The Hayes process by the very nature of its design and operation will treat a much wider range of coals than would be possible in batch processes"...

Economic Data: The economic data presented in Part V of this report are based upon the following quotation from the company:

"The estimated first cost of the plant includes material handling equipment, a reasonable land cost, retorts, condensers, gas scrubbers for recovering light oils, storage tanks for crude tars, crude light oils, and a 10,000 cu ft gas receiver.

"If further chemical separations of the tars are desirable these must be figures as a separate proposition and their cost balanced against increased income from the separations made. All piping, machinery, and a steam boiler plant are included in the plant cost".

Wisner (1252) ~ The history of the Wisner or Carbocite process, invented by Clarence Wisner, may best be presented by quoting in part the statements of Lesher and Zimmerman:

"To find use for the thousands of tons of ‘sludge’ produced at its coal-cleaning plants and to meet a market seeking a smokeless, clean, trouble-free, reactive solid fuel, the Pittsburgh Coal Co in 1928 began to interest itself in the manufacture of such a product...

"During 1929 and 1930, 200 tons of the company’s coal was... tested by the Plassman and Illingworth processes... and the Wisner process test plant...

The first unit was built in Champion, PA and had a capacity of 60 tons of coal per day. A second and larger retort of refined design was added to the plant in 1934, and a third still larger retort built in 1935 brought the total capacity of the Champion plant up to 325 tons of coal per day. The plant is operating today with apparent success, producing a solid smokeless fuel in the form of semi-coke balls sold under the trade name of "Disco".

Details of Process: As originally designed and tested, the process provided two stages for the treatment of coal, "thermodizing" and "carbonizing", both performed in continuous type rotary retorts. These retorts each consisted of two concentric shells, the coal passing through the center shell and the heating gases between the two shells. The outer shell was insulated and the heating gases were admitted through more or less complicated seals. In later designs the rotary "thermodizer" has been replaced with a roaster with rectangular hearths over which the coal is carried by rabbles on endless chains. The roaster or thermodizer not only dries and preheats the coke but through controlled oxidation it also reduces the coking power of the coal so that the adhesion to the carbonizing shell is prevented. In the last two units installed at Champion, circular, multi-hearth Wedge-type rabble roasters were used. In the later design of carbonizer the two concentric and revolving shells were abandoned for one single revolving shell and a fixed or stationary outer hood extending its entire length. The heating gases pass between the hood and the revolving shell or drum, thereby simplifying the construction by elimination of complicated seals. The largest of the three retorts at Champion is 8 ft in diameter and 126 ft long, inclined from the horizontal ½ inch per foot, and rotates at 2.75 rpm.

Volatile distillation products leave the retort at the upper, or feed end and pass through a chamber where dust is collected over a water seal. The wet dust is removed and used as a boiler fuel.

Coals Used: The Wisner process was developed specifically for the making of "balled coal" from coking coals. Weakly coking coals are successfully made into coal balls or Disco by a modification of the pretreatment. Any conception of the application of this process that would require briquetting of the final product is not in conformity with the Wisner process.

The Champion #1 coal used has an agglutinating value of from 7 to 8 (15:1 sand:coal ratio) and is usually mixed with 20% recirculated semi-coke breeze. This mixture as it is fed to the carbonizer has an agglutinating value of between 3 and 4. The preferred coal size is minus 4-mesh.

The two most important patents covering the process are the Wisner USP # 1,756,896 and the Lesher USP # 2,0808,946.

Tests Made with Utah Coals: [Not included here]
Economic Data: [Not included here]

Horizontal Internally-Heated Rotary Retort ~

Suncole  (# 1236)

Vertical Externally-Heated Stationary Retorts ~

Coalite (# 1152)

Figure 97 ~ Coalite Retort
Figure 98 ~ Coalite Plant Layout

Hird (# 1179)

Figure 99 ~ Hird Retort

Vertical Internally-Heated Stationary Retorts ~

Coalene (# 1151)
Derby-Horner (# 1159)

Figure 100 ~ Derby-Horner Carbonizing Unit

Karrick (# 1186): History: The history of the Karrick process may be said to have begun in 1921 when the inventor, Mr Lewis Cass Karrick of Salt Lake City, UT became interested in the carbonization of oil shale. Reports (# 469, 470, 471, 475, 476) have been written on the products obtained experimentally with the Karrick continuous process at the US Bureau of mines Pittsburgh Station just previous to 1927. Beginning in 1932 and continuing until 1935, a series of reports (# 1186) were made on laboratory tests of the Karrick static retort, batch process.

Mr Karrick has been granted numerous patents (Part VII of this report) covering methods and apparatus for carbonizing coal and similar materials at low temperatures. Included in these methods is the use of superheated steam in direct contact with the charge being treated. Several experimental laboratory retorts employing this method have been erected and tested using a number of Utah coals, but as yet no commercial application has been made of the Karrick processes.

Details of Process: Mr Karrick’s batch process using a static retort and superheated steam will be described here briefly.

The coal is carbonized in a vertical cylindrical tube about 5" in diameter and 6 ft long (although cylinders approximately 10" in diameter and 10 ft long have been sued) provided with removable lids at the top and bottom for charging and discharging. Superheated steam at a temperature of about 650 C (1202 F) and usually at about 10 psi pressure is admitted to the retort at the top and passed downward through the coal charge and in intimate contact with it. Steam and volatiles are taken from the bottom and passed to the usual condensing and scrubbing system. After carbonization has progressed to a certain stage, the flow of superheated steam is discontinued. Saturated steam is then admitted to complete the distillation of the lower portion of the charge by the transfer of the heat in the upper portion of the lower part, and at the same time to dry-quench the semi-coke.

In order to increase the efficiency of the process, Mr Karrick has devised an operating cycle using three interconnected retorts, whereby one retort is used for each of the 3 stages of carbonization, namely: preheating, carbonizing, and dry-quenching. The steam and volatiles from the retort in the carbonizing stages are passed into a second retort for preheating the charge therein and the steam and volatiles therefrom passed to the condensing system (Steam and volatiles from the retort undergoing dry-quenching are also passed to the condensers). At the completion of this phase, the flow of steam and vapors is changed so that the carbonizing retort is dry-quenched, the one being preheated is raised to carbonizing temperature and quenched semi-coke in the third is discharged, a new batch of coal is charged, and preheating is begun. It is said that by this procedure a distinct saving of steam can be effected.

Coals Used: The process in the present stage of development is adaptable only to sized lump coal having non-coking or mildly coking characteristics. Coking coals or small-size coal tend to reduce and in some cases prevent the flow of steam through the charge, thus making carbonization difficult if not impossible.

Economic Data: The Foundation asked Mr Karrick to supply cost and revenue data and other pertinent information relative to this process in order that it could be compared on the same basis as other methods. However, the data were not made available. Some economic data, however, have been presented in a published report which is now 7 years old.

Lurgi (# 1197)

NFC (National Fuels Corporation) ~ History: Work on the process was begun about 10 years ago by M. Poucher. In November 1929 the basic British patent was granted to the NFC of NY city... Mr G. A. Berry, VP of NFC, is now directing the exploitation of this process and has several patents in his name relating to LTC. A number of patent applications are now pending both in this country and abroad.

Plant: The only plant in operation is located at New Haven, CT and is capable if treating from 5 to 10 tons of coal per day. It is used for experimental purposes at the present time to obtain operating data when using various coals. No commercial plants have been erected to date.

Details of Process: The process is designed to produce, from a wide variety of coals, a smokeless fuel or semi-coke of highly satisfactory characteristics. Usually the fuel is in the form of briquettes, but lump coal also may be treated.

The retort consists of a vertical, insulated chamber similar to that shown by the diagrammatic sketch, Fig. 102. It is continuous in operation, the raw fuel being fed in at the top through a suitable charging mechanism, and the semi-coke being extracted from the bottom through a water-seal.

The retort is heated internally by the gas that is generated from the coal itself. Following is a description of the gas circuit shown in Fig. 102.

Figure 104 ~ Analysis of Tar Products, NFC Process

Starting with the gas offtake at the top of the retort, at which point the gas temperature is about 150° C (300° F), the distillation products flow through the usual type of hurdle-scrubber where they are water-cooled to about room temperature, and where the major portion of the entrained tar vapors are condensed and separated. The stream then passes to a tar extractor where the last of the tar mists are removed. The cleaned gas then passes through the exhauster at the exit of which the pressure is built up sufficiently so that the gas stream emerging from the retort at the gas offtake is at atmospheric pressure.

On the outlet side of the exhauster the circuit is divided. Gas in excess of that required for carbonization purposes is bled off to the usual type of gas purification apparatus, after which it is suitable for use as city gas or for industrial purposes. Another portion of the gas from the exhauster is burned in a gas heater through which is circulated in counterflow still another portion of the total gas, labeled in the figure as "tuyere gas". This heated gas is fed into the retort through tuyeres, in volume necessary to overcome only the radiation loss from the retort itself plus the actual heat required for carbonization and the sensible heat of the issuing volatile products. Finally, a portion of the total gas is used for quenching the finished semi-coke to room temperature. This gas enters the retort at the bottom in volume sufficient to abstract the sensible heat of the descending semi-coke. By the time the gas reaches the elevation of the tuyeres, its temperature is equal to that of the fuel at this elevation and also to that of the entering gas from the heater.

The temperature of the gaseous carbonizing medium issuing from the heater may be regulated so that the semi-coke will be carbonized at any finishing temperature that may be desired, usually either 600° or 800° C (1112° or 1472° F). Thus, carbonization is effected by passing through the charge a volume of hot gas derived from the coal itself, and not by circulating products of combustion as is the usual practice. In this fashion, the distilled fuel gas is not diluted with a large volume of gaseous heating medium of low calorific value, and consequently a high Btu gas is produced for domestic and industrial purposes. Of course, if there is no market for this gas, arrangements are provided to burn the coal gas in a chamber outside of the retort and to pass the products of combustion directly through the coal charge to effect carbonization.

With the volatile products issuing from the top of the retort at 150° C, this means that there is a gradual increase in the temperatures of the fuel from its point of entry to the level of the tuyeres; and that carbonization proceeds in successive steps so that the volatiles are quickly removed at their respective vaporization temperatures. In conclusion, it is evident that in this process carbonization and cooling are carried out in one retort through which the coal is fed continuously.

Coals Used: It is claimed that almost any bituminous coal is adaptable to this process. Coal in lump or briquetted form can be used. The rate at which treatment may occur, however, is a function of the composition of each particular coal. Coals which have an excessive tendency to melt and soften during the early stages of distillation may nevertheless be processed without incurring the swelling or slumping of the briquettes if the time-temperature gradient is of about the order of 0.5° C per minute through the zone a which the condensable hydrocarbons are being rapidly evolved. For other coals this rate may be as his as 5° C per minute. In general, average rates of from 2° to 3° C per minute may be assumed as that of general practice.

In making the briquettes it is claimed that the process is adaptable to many of the well-known products now on the market as binder material, of which those of the water-soluble variety are preferred.

When the coal is carbonized in briquette form (Fig. 102) it is first ground to minus 20 mesh and then fluxed with the appropriate binder. From this mixture pillow-shaped briquettes are then formed in a suitable briquette roll. They are dried, heated to 150° C, and fed into the top of the retort.

The carbonization period will vary from 4 to 6 hours depending upon the coal treated and the finishing temperature which may be varied and accurately controlled between 500° and 900° C (932° and 1652° F).

It is claimed that the overall thermal efficiency of the process is close to 80%.

Plant Performance: It is reported that this plant, experimental in nature though it may be, operates with a minimum of attention form the operator. Mechanisms have been used in the plant design with permit operation to proceed for days at a time without the necessity of touching or adjusting a single control.

Tests Made With Utah Coals: [Not included here]
Briquetting Tests: [Not included here]
Lump Carbonization: [Not included here]
Comments & Conclusions: [Not included here]
Final Report: [Not included here]
Economic Data: The bases for the economic data tabulated in Part V of this report are given by the company according to the following quotations:

"The size selected for the commercial unit is one capable of processing 580 tons/day of 24 hours, of raw dry briquettes, at a rate of 2-1/2° C per minute. Annual capacity is based upon a year of 328 working days.

"The estimated costs are for completed installations, ready to operate... Neither cost of land nor preparation of the site for the construction is included. The estimates include all foundation masonry necessary for the building and equipment, based upon average safe bearing values for the soil.

"The estimated costs for service lines, as water, electricity, railroad tracks, sewers, etc., presupposes such facilities are immediately adjacent to the property, and the estimates therefore do not comprehend costs extending beyond the boundary line of the plant property.

"The estimate is adequate to provide a raw coal stocking capacity of about 10,000 tons, stored under cover, and a like capacity for the finished product, stored in the open, as well as in a 400-ton elevated bin, from which either trucks or railroad cars may be loaded by gravity. For both installations, however, adequate handling facilities, as belt conveyers and the like, are provided to balance the full daily plant capacity. These storage capacities are deemed ample for any location which permits, throughout the year, fairly uniform receipt and delivery of the raw material and the finished products respectively.

"The estimates include not plant or equipment essential for the purification of the gas from ammonia or hydrogen sulfide to meet the usual specifications for City gas. This item has been designedly omitted from these estimates until definite decision has been made as to the disposition of the surplus gas. Should such gas be sold for industrial rather than for City use, it is probable that additional purification above that comprehended in the plant estimate will not be needed. Electrostatic precipitators are, however, provided for the freeing of the gas from the last of the tar fog. Should, however, such gas be sold for domestic consumption, then appropriate additions to both capital and operating costs should be made. Both the equipment and the processing for such further purification of the gas will be identical with generally accepted practice for oven gas.

"Because the concentration of light oils in gas made by the NFC Process seems to be less than pertains to oven gas, it is believed, should such recovery be desirable that an absorbant, as activated carbon, should be employed rather than to use the usual type of oil scrubbers. The estimates comprehend no equipment of this character.

"For the tar, no equipment is provided in the estimates beyond the dewatering centrifugals, other than storage facilities for tar with the necessary pumps for the servicing of the same. Later on, if it be decided to process the tars as part of the regular operation, adequate estimates of capital and operating costs will be provided.

"The estimates are not inclusive of Contractors’ profits or fees, power and light, operating labor, and water.

"The binder employed is Utah Molasses, in the proportion of 4% thereof of the dry substance...

The charges for maintenance, depreciation, taxes and insurance have been worked out for each item of the plant, but are shown as percentages of the total capital cost including foundations and the like".

Rexco (# 1222) ~ History: Originally developed in the US for the distillation of oil shale, the basic US patent covering the Rexco Process was filed in 1922 by David Davis and George Wallace. After a period of several years the process was adapted to the treatment of coals.

At the present time the only company exploiting this method is the National Carbonizing Co Ltd of London, which is a licensee under the British Patents of Mr Wallace...

Figure 106 ~ National Coal Carbonizing Co Mansfield Plant
Figure 107 ~ Diagram of Rexco Plant

In 1925 at Rulison CO the US Bureau of Mines erected an experimental oil-shale station for the purpose of determining "the feasibility of producing shale oil as an emergency or future fuel supply for the Navy". A 25-ton/day Rexco unit, then known as the NTU (Nevada-Texas-Utah) retort, was installed and operated from Jan.17- June 26, 1927. A total of 788 tons of shale were treated. The plant was sold and dismantled when the appropriations for the work terminated in June 1929. The operating results were summarized as follows:

"The test runs that were made, however, indicate that the internal-combustion type of retort has definite possibilities for commercial retorting plants".

In 1931 work was begun on a commercial plant... Two retorts were built, each with a capacity of about 37 tons of coal and the two together originally carbonized about 90 tons of coal/day. Since the beginning of 1936, the pant has been in continuous operation except for short periods to make minor repairs and improvements to machinery.

The British Fuel Board conducted a test of the Mansfield plant. They concluded that "no difficulties of major importance were encountered during the period of test".

According to the company, no important modifications in the design of the existing retorts have been made since the date of the above test. However, refinements have been effecting in the operating technique mainly for the purpose of increasing plant capacity.

The carbonizing and cooling periods have been reduced. The practice of quenching in the retort with water was discontinued because of its detrimental effect to the quality of the semi-coke. Subsequently, cooling was done by passing gases through the retort. It is now planned to employ an external cooling chamber, which will make it possible to carbonize 56 tons of coal per retort per day. Also by this system, the heat required for carbonization has been reduced from 1000 Btu to 850 Btu per lb coal.

The NCC reports that, "as a result of our operating experience an important modification of the method of combusting the heating gases has been incorporated in our new design or retorts to be installed. This will enable us to maintain our high rate of throughput with more ease than at present and enable automatic temperature control to be utilized. Also, it will make it possible to work at lower temperatures of carbonization, which seems desirable in our experience here, and at the same time to secure even greater uniformity in the carbonization from the top to the bottom of the charge. These improvement are subject to Letters Patent in Britain"...

To obviate the breakage of the semi-coke during discharge from the retorts, a new type of discharge platform has been designed. This equipment, however, can only be fitted to the new retorts.

Details of Process: The object of the Rexco process as used in England today is he production of a smokeless and reactive domestic coke in lump form, and also tar-oil.

The coal is carbonized in two cylindrical, vertical, steel-plate chambers lined with firebrick. Each chamber is 24 ft high and has an inside average diameter of about 10 ft with a slight inverse taper from top to bottom. Above this almost cylindrical portion is a roughly hemispherical dome, at the top of which is the charging opening. This opening is covered during the carbonizing period by a cast-iron door.

Near the top of the hemispherical portion of the carbonizing chamber is admitted a mixture of 40% air and 60% gas by volume. The gas has a heating value of about 140 Btu/cu ft, and is produced from the carbonization process. Combustion of the gas-air mixture takes place within the retort above the top of the coal charge. The gaseous medium travels downward through the retort charge and passes with the volatile products of carbonization through a slightly inclined brick grate which supports the charge. The quantity of gas circulating through the coal is always materially in excess of the amount of air required for its combustion. The speed of gas circulation, and the amount of air admitted are controlled to give the proper speed and temperature of distillation. It is claimed that the response to such control is direct and quick, as there are no containing walls through which the heat must first travel. Because of this method of heating the company states that it is possible to carry out carbonization in bulk, with consequent saving in operating costs, and at the same time to produce a smokeless fuel of uniform quality and of controlled volatile content.

Because the oil vapors are swept downwardly to a cooler zone and are therefore not subjected to a temperature higher than that at which they are formed, secondary decomposition of the distillation products is prevented.

The process is limited in that it can deal only with non-coking or slightly coking coals, free from fines. The coal treated at Mansfield is sized to minus 4-plus 1-1/4" and a charge consists of approximately 2/3 of "top hards" or non-coking coal and 1/3 "bright coal" which is slightly coking. [i.e., 5.3% moisture, 34.6% volatile, 55.2% fixed C, 4.9% ash].

The coal is elevated from a storage bin by an inclined belt conveyer to a bar screen where the fines and dust are removed. The screened coal then falls by gravity into the retort through a telescopic chute, the purpose of which is to prevent excessive breakage of the coal. As the coal is fed, the chute is gradually raised, and when the charging is completed, this device is removed from the retort.

The charging operation requires about 40 minutes. In a larger plant, it may be desirable to provide coal bunkers above the retorts in order to facilitate the charging process, when the charging time would then be approximately 10 minutes.

The coal is supported on a slightly inclined brick grate which is mounted on wheels. To discharge the semi-coke, the grate is hydraulically withdrawn in a horizontal direction. This operation takes 3 to 4 minutes.

Upon discharge, the carbonized fuel passes over an inverted V-shaped bench placed directly below the retort. In this manner, breakage of the smokeless fuel is largely eliminated. Mechanical equipment is used to screen the material and to transfer it to storage bins.

The reject coal under 3/8", screened out before charging, is returned to the coal company for sale. Over a period of one year, it amounts to from 3 to 3-1/2%.

Temperatures within the retort vary from 850° C (1562° F) at the top to 500° C (932° F) at the bottom, the upper reaching 500° C after the carbonization has been in progress for approximately 12 hours. A complete cycle of operation for one retort consisting of charging, distilling, cooling, and discharging, requires about 18 hr. When the temperature of the vapors leaving the retort is about 375° C (707° F) the air supply to the top of the retort is cut off and the circulation of the gases continued, thereby cooling the upper portion of the charge and transferring the sensible heat of that portion to the lower part of the charge.

This procedure effects a saving in fuel required for carbonization, and also decreases the distilling time. The temperature of the cooled semi-coke ranges from 175° to 200° C (347° to 392° F).

During at least one-half the combined carbonizing and cooling period, the temperature of the vapors leaving the retort is low enough to permit condensation of the tar oils. About 70% of the tar reaches the bottom of the retort as a liquid.

The volatile products together with the liquid tar pass from the base of the retort to a spray washer, whose primary function is to cool the fuel gas and complete the condensation of tar. It operates mainly during the latter part of the period above mentioned, when the temperatures of the vapors from the retort rises from 100° to 500° C (212° to 932° F). The water supply to the washer is then increased to maintain a gas outlet temperature of from 30° to 35° C (86° to 95° F).

Next, the fuel gas is passed through a cyclone where the water vapor and tar fog are removed. All of the tar-oil is removed from the washer and cyclone. An exhauster, located after the cyclone, is operated to maintain a vacuum of a few inches of water at the retort offtake. A light oil scrubbing tower [is] installed in the gas line after the exhauster. In this way a few gallons of gasoline can be recovered.

After passing the exhauster, the fuel gas is divided into two streams, one of which returns gas to the retort for carbonization purposes, while the other carries the excessive gas to a liquid evaporator where it is burned. The excess gas amounts to about 25,000 ft per ton of coal treated.

The water used in the spray washer is maintained in a closed circuit. From the washer it passes with the tar into the settling tank where the tar and water are separated. The water is then pumped into a wooden tank, natural draft open type Premier cooler, to be returned as needed to the spray washer.

According to the company, "The ammonia concentration in the recirculated liquor or effluent always remains low, as from time to time a quantity is withdrawn from the system and replaced by fresh water. The reason for this is that there is a gradual concentration of the fixed ammonium salts in the liquor (the free ammonia in solution is never high), tending to raise the specific gravity of the liquor, which would hinder the free separation if allowed to reach the specific gravity of the tar. The relatively small quantity of liquor withdrawn regularly from the circulating system contains, in addition to fixed ammonium salts, certain phenolic constituents in solution, but the amount of either is not sufficient to warrant working up for recovery in this country" (England).

At the present time, the withdrawn liquor is passed to the evaporator previously mentioned. The brick checkerwork of the evaporator is heated with the products of combustion generated from the excess gas referred to previously. The liquor is sprayed over the hot brickwork and evaporated, but the ammonium slats and phenolic bases are decomposed into their respective elements and oxidized.

Advantages: The important advantages claimed for the bulk carbonization as carried out by this process are: (1) Low capital cost of plant, (2) Low upkeep and maintenance charges, (3) Low cost of operation in which low, skilled labor charges are an outstanding example, (4) Extreme simplicity of operation and control of the carbonization process, (5) Ease and rapidity with which the plant can be started up and shut down with no possibility of damage, (6) Robustness of construction and absence of complicated  firebrick furnace work and heating flues, (7) No standing charges as regards keeping carbonizing units under slow fire when not required, and no expensive and long heating-up periods, (8) Being of unit construction, the plant can be cheaply extended when and as required.

The company states that, "The firebrick linings are the same as installed when the plant was first started in 1935, and they have only had the joints repointed in the upper portion and the firebrick chargehole rings renewed".

Products & Properties: The semi-coke finds a ready sale for power-house boiler firing when admixed with coal, since better combustion results from this practice than when coal alone is used. The company says that "we could now sell many times our output of breeze for this purpose".

A local tar company purchases the crude tar-oil for the manufacture of disinfectants and insecticides.

Outside of the semi-coke, no other products are made. Ammonium compounds are not produced, and the light oil or "motor spirit" is not recovered.

According to reports the volatile content of the semi-coke from the top and the bottom of the retort varies from 3 to 4%. This difference is equalized after discharge by mixing to give a fuel with an average volatile of 7%. There is no oxidation or burning of the coke at the top of the charge, resulting from the combustion of the gas and air mixture. The new retort design, mentioned previously, is claimed to be capable of largely eliminating the present difference in the top-bottom volatile content...

Economic Data: The two products sold are: (1) Semi-coke (yield 65%, (a) Large (over 1-1/8", 66.5%), (b) Nuts (3/8", 20%), (c) Breeze (under 3/8", 13.5%); (2) Tar...

When using 4 retorts instead of 2 as at present, Mr Wallace estimates that this cost would be cut in half. The present 2-unit plant, Mr Wallace says, is paying its own way and earning a small profit.

Patents: The process and apparatus for this method of distilling coal and other carbonaceous material is apparently covered completely by the US Patents # 1,491,290 and # 1,536,696...

Tests with Utah Coals: [Not included here]

Suitability of Process: As summarized by Mr Wallace, "My opinion is that any of the three coals which you submitted for tests... would be satisfactory, and further, I have never seen a sample of better smokeless fuel than that produced... from your coal.

"From our point of view, we are certain that all of the non-coking bituminous Utah coals can be satisfactorily carbonized by the Rexco process".

It is to be noted that no equipment is provided for the removal of ammonia and hydrogen sulfide from the fuel gas...

Mention is also made of the manner in which the aq. liq. is treated... The liq. So withdrawn is then evaporated in a suitable unit which is heated by the excess gas. By this system, there is no liquor which has to be wasted to an open stream...

Recommended Carbonizing Procedure: For a plant having a daily capacity of 500 tons and treating Utah coals, the following recommendations have been made by the NCC:

Average Carbonizing Temperature: 650° C (1202° F); Number of Retorts: 12; Capacity of Retorts: 35 tons; Time of Carbonization (including charge/discharge): 16 hr per retort; Coal Size: ¾" to 3".

Economic Data: The economic data is in Part V of this report. Construction costs include the retorts, buildings, tankage, gas exhausters, coal and coke handling equipment, and all necessary equipment for the operation of the plant. The costs of a suitable gas holder and land are not included.

Trumble (# 1246)

By-Product Coke Oven Type Processes ~

Gibbons/Cellan-Jones (# 1169)

Figure 108 ~ Gibbons/Cellan-Jones Oven Discharge, 5-Ton Capacity Coal Car
Figure 109 ~ Arrangement of Gibbons/Cellan-Jones Oven Battery
Figure 110 ~ Top of Gibbins/Cellan-Jones Ovens
Figure 112 ~ Proposed Gibbons/Cellan-Jones Oven Battery

Kemp (# 1187)
Lecocq (# 1194)

Figure 113 ~ Lecocq Semi-Coke Oven

Coal-Oil Mixture Processes ~

Cannock (# 1144)
Gifford (# 1170)


Part V

Technical & Economic Factors Concerning the Application of LTC to Utah Coals

Chapter 11

General Considerations

[Not included here (smoke & costs)]

Table 18 ~ Comparison of Analysis & Heating Value of Natural Gas & LTC Gas


Chapter 12

Economic Analysis of Major Processes

As a guide to the study of the following material [Not included here: charts], the reader is referred to Chapter VIII in which the Major Processes are defined, and also to Chapter X which presents in detail the technical and other pertinent information secured for each of these processes...

Explanation of Table 19: The figures are based upon plant capacities ranging from 500 to 580 tons of coal per day. These capacities are stated to be sufficient to give economical operation. For each process, the data are given for a carbonization plant located at the mine and at Salt Lake City...

The plant cost is estimated at 10% per annum on the total investment in order to place each process on a comparable basis...


Chapter 13

Selection of Most Suitable Processes

Application of Major Processes to Local Requirements ~

The most suitable processes for the purposes of this investigation are defined in the introduction to this report. The limiting factors which entered into the selection of the most suitable processes and the basis for classification of processes into Minor and Major Processes, are presented in Chapter 8. Chapter XI gives the major considerations to be met in the application of LTC to Utah coals, and Chapter 12 provides detailed economic information. It now remains to select the most suitable processes to meet the local requirements, i.e., the economic production of (1) semi-coke for use in existing hand-fired combustion equipment, and (2) semi-coke for use in existing stoke-fired installations. [Note: notice that there is no mention of tar-oil.]

Semi-coke for Use in Existing Hand-Fired Combustion Equipment ~

According to the types of Major Processes reviewed in this report, there are 5 distinct methods of producing semi-coke in pea or somewhat larger sizes for use in existing hand-fired combustion equipment. These methods are (1) the carbonization of coking coal and blends of coking and non-coking coals in modified byproduct ovens, (2) the carbonization of coking coal and blends of coking and non-coking coals in (a) vertical, externally-heated, static retorts, or in (b) externally-heated rotary retorts, (3) the carbonization of coal-oil mixtures in various retorts, (4) the carbonization of sized non-coking coals in either vertical or rotary retorts to produce semi-coke in essentially the same form as the raw coal from which it is made, and (5) the carbonization of small sizes of non-coking coals and the admixture of a binder either before or after carbonization to produce semi-coke in briquetted form.

Carbonization of Coking Coals & Blends in Modified By-Product Coke Ovens: These processes utilize the most inexpensive size of coal which may be obtained wither from the mine crushing plant or from the "sludge" of a coal-washing plant.

Methods for carrying out the carbonization of coking coals only in modified byproduct coke ovens necessarily would be limited to the two coking coals of Utah (Lower & Upper Sunnyside)... As discussed in Chapter 11, this scheme would not be practicable since only the coking coals would be utilized and the by-products of non-coking coals from the more extensive Utah coal deposits would be eliminated from the field of LTC. Furthermore, Utah’s deposits of coking coal should be reserved for the manufacture of by-product coke for the important smelting operations of the state.

The treatment of blends of coking and non-coking coals of Utah in modified by-product coke ovens also has been shown to be impracticable (Chap. 7 & Gibbons/Cellan-Jones Process, Chap 10). Utah’s coking coals are in reality poorly coking and possess no excess binding material to form a non-friable coke when used in reasonably small percentages with the non-coking coals of Utah...

On the basis of the above criteria and data, the Gibbons/Cellan-Jones, Kemp and Lecocq processes are not considered to be the most suitable processes.

Carbonization of Coking Coals & Blends by Other Methods: The carbonization of coking coal and blends of coking and non-coking Utah coals in vertical, static, externally-heated retorts is likewise considered to be impracticable upon the basis of the above criteria. Therefore, the Coalite process is eliminated for the production of semi-coke from Utah coking coals and blends of these coals with non-coking coals.

The Wisner process employs coking coal and blends of coking and non-coking coal to produce semi-coke in the form of balls... We have eliminated the Wisner process from further consideration insofar as the production of semi-coke for use in hand-fired combustion equipment is concerned.

Carbonization of Coal-Oil Mixtures: Processes for the production of semi-coke from mixtures of coking, weakly-coking and non-coking coals with heavy oil or tar apparently are in the development stage... On the basis of agglutinating studies conducted by the Foundation (Chap. 7), it appears that coal-oil mixtures have little practical application in Utah coals... The Cannock and Gifford processes are therefore eliminated from further consideration.

Carbonization of Sized Non-Coking Coals: The carbonization of non-coking Utah coals in pea or somewhat larger sizes may be carried out in numerous ways. The methods covered by the major Processes are listed below:

Vertical, Externally-Heated Stationary Retorts: Coalite, Hird.

Vertical, Internally-Heated, Stationary Retorts: Coalene, NFC, Derby-Horner, Karrick, Rexco, Lurgi, Trumble.

Horizontal, Externally-Heated Rotary Retorts: Davidson

The fundamental basis for the selection of the most suitable processes to treat sized non-coking coals for use in hand-fired equipment is contained in the definition of the most suitable processes as given in the Introduction of this report. In effect, this definition states that the most suitable processes are those that produce the best semi-coke which may be sold at the lowest price.

The desired properties of semi-coke are given in Chap 2 and 11. In our experience, a sufficiently reactive semi-coke which will ignite easily and maintain a ready fire may be produced from the non-coking coals of Utah by almost any method of treatment. However, the requirement of sufficient mechanical strength to withstand normal handling without excessive degradation, may not be met to the same degree by all of the Major Processes. In fact, the mechanical strengths of semi-cokes made from sized non-coking coals are low in comparison with the strengths of semi-cokes made from coking Utah coals or the strengths of briquetted semi-cokes...

For Utah non-coking bituminous and sub-bituminous coals, the maximum breeze is produced from coals of the lowest agglutinating values when carbonized in a rotary retort, while semi-cokes of the greatest mechanical strengths are produced in vertical, externally-heated retorts (Chap. 6 & 7)...

From the above considerations, it is evident that degradation of sized non-coking coal during carbonization and the subsequent production of a semi-coke of doubtful required mechanical strength, raises important problems which at this time may be analyzed only in problematical terms. Obviously, the process most likely to prove suitable for the treatment of sized non-coking Utah coals must have a low carbonizing cost in order to compensate for the above-contemplated variations in the economic production and sale of the semi-coke.

A study of Table # 19 will show that the costs of production listed in Column 30 reflect the ultimate results of many important technical factors for each process. That is, the heat required for carbonization has an economic value, the magnitude of which depends upon the source and the quantity of the heating medium. Plant construction cost will be the greatest for a plant of complicated design and requiring the greatest use of special materials and equipment, and requiring the largest number of individual operations to process the fuel and to obtain the by-products. Likewise, labor costs care a direct measure of the simplicity with which manufacturing operations may be conducted. Moreover, depreciation charges are a measure of the overall life of plant equipment.

However, operating costs do not indicate the ease with which the carbonizing process may be controlled and maintained to a given set of conditions, or the ability of the process to be adjusted to a wide range of carbonizing temperatures. These are considered to be important items in the selection of processes, since the products must be of reasonable uniform quality and the process must be flexible enough to permit economical operation under charging market conditions...

Selection of the most suitable of the above-listed processes may now be made upon the basis of the foregoing criteria and economic data presented in Table # 19.

The treatment of coal at low temperatures in vertical, externally heated stationary retorts must be conducted in chambers of small diameters in order that a uniformly carbonized semi-coke may be produced. This requirement necessitates the use if a large number of retorts for the manufacture of semi-coke in commercial quantities. Charging and discharging mechanisms are therefore required for each retort, whether they are of continuous or intermittent operation. Also, the transfer of heat from a gaseous heating medium though a wall of metal or brick and thence to the coal, is not as efficient as the transference of heat directly from the heating medium to the coal. Economic data were not furnished for the two processes of this type, namely the Coalite and the Hird processes. However, on the basis of the foregoing criteria and information, it is our opinion that the Coalite and Hird processes are not the most suitable processes for the treatment of sized non-coking Utah coals.

Major Processes using vertical, internally-heated, stationary retorts employ as heating medium (1) superheated steam, (2) products of combustion generated from the burning of coal, or fuel gas obtained from the carbonization process, and (3) fuel gas obtained from the carbonization process which is heated to the temperature required for carbonization. Carbonization effected by passing the above-mentioned heating media in intimate contact with coal, materially increases the rate of transfer over that obtained in externally-heated retorts, and makes the use of large retorts practicable.

Superheated steam was employed as a heating medium in the early development stages of LTC. At the present time, processes using superheated steam have not met with notable commercial success either in the US or abroad. The heat required to completely vaporize water to form steam cannot be utilized for carbonization purposes since the vaporization temperature is far below the required carbonizing temperatures. This heat of vaporization represents more than one-half the total heat of steam superheated to the temperatures necessary for carbonization. Various heating-cycles and heat-exchangers have been proposed in an effort to economically utilize the heat of vaporization in the steam after it leaves the retorts. Such devices tend to complicate the operation of the retorts and to increase the construction and operating costs. Unless cheap sources of steam are available, the cost of generating steam and superheating it to the required temperatures may be greater than the cost of generating gaseous heating media from the combustion of fuels. Moreover, special steels are required for the superheaters and special valves are necessary to control the flow of superheated steam.

Of the three superheated steam processes reviewed in Chapter 10, the Trumble process appears to have the most definitely planned method of recovering the heat of vaporization, and is the only one for which complete economic data were submitted. These data show that the processing cost is quite reasonable but not the lowest for all processes that employ internal heating (Table # 19). On the basis of the above considerations and data, processes using superheated steam, i.e., the Coalene, Karrick, and Trumble processes in our opinion are less suitable than the other methods of carbonization.

The Derby-Horner, Lurgi, and Rexco processes use gaseous combustion products as the heating medium. Complete economic data were obtained for the Rexco process only, and it is worthy of note that the estimated production cost ($0.44/ton of coal) is the lowest of all the processes listed in Table # 19. It will be recalled that the estimated processing cost by the Lurgi process (Chap 10) is stated to be $0.75/ton of coal. One naturally would expect this cost to be higher than that by the Rexco method, because of the more complicated design of the Lurgi process. Likewise, from the standpoint of simplicity in retort design and of operating technique, the cost of treatment by the Derby-Horner method in our opinion would be greater than by the Rexco process, although no economic data were made available.

The importance of choosing a process for the treatment of sized non-coking coal that would be able to operate at a minimum total cost, has been discussed in earlier paragraphs... The Rexco process... has the lowest estimated operating cost... Also, the mechanical strength of the semi-coke should be good and the amount of breeze should be relatively small because of the high static head of coal which would provide pressure to compress the lumps during the plastic stage of carbonization. In view of the above data and the foregoing criteria, we consider the Rexco process to be the most suitable process using gaseous combustion products to effect the internal carbonization of sized non-coking Utah coals.

The NFC (National Fuels Corp.) process is not to be confused with the Derby-Horner, Lurgi, or Rexco methods, since this system utilizes as the internal heating medium a portion of the fuel gas obtained from the carbonization of coal (Chap. 10). While the processing cost by this method is $1.05/ton of coal, yet there are two compensating factors which make the process outstanding. First, the yields of oil are considerably greater than usual, and second, the heating system is very unique and probably is the most efficient of all heating systems studied during this investigation... In view of the above data and the foregoing criteria, we believe that the NFC method should be given the opportunity for further investigation on a semi-commercial scale for the treatment of sized non-coking Utah coal. For the purpose of this investigation, therefore, we consider the NFC process to be another method most suitable for the treatment of sized non-coking Utah coals.

Processes using horizontal, externally-heated rotary retorts causes each particle of coal to come in contact with the heated surface of the carbonizing cylinder. In this manner, the rate of heat transfer is high and the semi-coke is uniformly carbonized. However, the rotation of the retort results in the production of considerably more fines than are produced by other types of retorts. (Chap. 6). Earlier in this section, it was shown that the production of breeze presents important problems which may adversely effect the economics of LTC. According to the data listed in Table 19, the estimated production cost for the Davidson process is relatively high. Therefore, on the basis of the above consideration and the foregoing criteria, the Davidson process is not considered to be a most suitable process for the carbonization of sized non-coking Utah coals.

Briquetting Processes ~ The cost of producing briquetted semi-coke is greater than the cost of making semi-coke from sized non-coking coals, because additional labor and machinery and a satisfactory binder are required. However, the cost of raw Utah coal suitable for briquetting is less than the cost of sized coals. Little if any fines are produced with briquetting, and the plant operator would be assured of a known return from the sale of the fuel. Screening of the raw coal at the plant, regardless of its location, would not be necessary. Briquettes from the Hayes, NFC, and the Suncole processes were considered to be of sufficient mechanical strength to withstand normal handling without excessive degradation.

An important factor to be considered in determining the economic feasibility of a briquetting process is the assurance of a steady and ample supply of a suitable binder which may be obtained at a satisfactory price.

The suitability of briquetted semi-coke for general use in hand-fired combustion equipment... may not be determined until large quantities are available for trial. Whether or not this fuel would be widely used cannot be determined at this time...

Upon the basis of the general criteria for "Carbonization of Sized Non-Coking Coals", and also upon the above information, the Suncole process is not considered to be a most suitable process, but the Hayes and NFC methods are determined to be the most suitable processes for the manufacture of briquetted semi-coke from Utah coals.

Semi-Coke for Use in Existing Stoker-Fired Combustion Equipment ~

The most economical way to produce semi-coke fines for use in existing stoker-fired combustion equipment, is to carbonize at the least cost, the most inexpensive size (slack) of non-coking Utah bituminous or sub-bituminous coals.

As mentioned previously, carbonization in vertical, externally-heated stationary retorts results in relatively low rates of heat transfer. The retorts, therefore, must be of narrow cross-section and of small capacity and production cast may thereby be increased. The White process, however, produces semi-coke instantaneously in a vertical, externally-heated retort, but no economic data were available to make possible further consideration of this method (Chap 9).

A charge of 100% slack coal cannot be efficiently treated in any type of vertical, static retort which is internally heated, because the total open cross-sectional area between the coal particles is too small to permit a sufficient volume of heating medium to flow through the retort so that carbonization is effected in a reasonable period of time. With some of the more fusible coals in slack sizes, sufficient agglomeration of the particles may take place during the plastic stage to prevent entirely the flow of heating medium.

Results of tests reported in Part III of this report show that the products of a rotary retort yield the greatest total revenue. The semi-coke is uniformly carbonized since every particle of coal comes in contact with the heated retort surface. On the basis of the information obtained during this investigation, it appears that the rotary retort presents the most satisfactory method for the production of semi-coke in small sizes. The transference of the vapor stream of fine material from the retort into the condensing system may cause difficulty. However, claims are now made that suitable equipment may be installed economically to settle out the coal and semi-coke particles so that the tar does not become so contaminated [i.e., ultrasound]. While semi-cokes from a rotary retort have the lowest mechanical strength (Chap 6), yet this property is not considered to be detrimental since mechanical strength is not an important requirement of stoker fuels.

Data shown in Table # 19 indicate that the production of semi-coke in small sizes from non-coking Utah bituminous coals is not economically sound...

Semi-coke produced from sub-bituminous Utah coal in small sizes may be sold at a much lower figure... Chemical analyses of the sub-bituminous semi-coke (Chap 6) show that it is at least the equal of semi-coke from bituminous Utah coals from the standpoint of heating value and ash content.

Upon the basis of the above data and criteria, the Suncole and Davidson processes are not considered to be the most suitable for the production of semi-coke in small sizes for stoker use. The Hayes process is the most suitable for the production of semi-coke in small sizes from sub-bituminous Utah coals.

Confidential cost data submitted by the Pittsburgh Coal Carbonization Co for the Wisner process indicated that the processing costs in a Utah plant might be in the neighborhood of the estimated processing costs for some of the most suitable processes previously named. Upon the basis of the foregoing criteria and the above confidential information, the Wisner process might be one of the most suitable processes for the production of semi-coke in small sizes from sub-bituminous Utah coals.


Chapter 14

The Most Suitable Processes

Semi-Coke for Use in Existing Hand-Fired Combustion Equipment ~

Semi-coke which may be satisfactory for use in existing hand-fired combustion equipment "may be economically produced from non-coking bituminous coals in (10 sizes ranging from slack to pea or somewhat larger sizes, and (2) in briquetted form. In case of the former type of semi-coke, degradation of Utah coals within the retort and the relative low mechanical strength of the fuel may adversely affect its economic production and sale. The continuous and economic supply of a suitable binder will have an important bearing upon the economic success of producing briquetted semi-coke". For these reasons, we have elected to name the most suitable processes on the following bases.

Scheme I. For the manufacture of semi-coke in sizes from slack to pea or somewhat larger sizes from non-coking bituminous Utah coals, the Rexco and NFC processes are considered to be the most suitable.

Scheme II. For the manufacture of briquetted semi-coke from non-coking bituminous Utah coals, the Hayes and NFC processes are considered to be the most suitable.

Semi-Coke for Use in Existing Stoker-Fired Combustion Equipment ~

Semi-coke in slack sizes for use in existing stoker-fired combustion equipment... may be made from Coalville sub-bituminous coals. Economic data presented in Table # 19 (Chap 12) indicate that an economically priced semi-coke may not be made from slack bituminous Utah coals. However, if the semi-coke for hand-firing purposes were made from sized non-coking coals according to Scheme I, slack semi-coke probably would be available for stoker use. The suitability of semi-coke in small sizes for stoker use has not been determined definitely, and hence it is not known whether or not to manufacture semi-coke for this purpose only, then we recommend the use of sub-bituminous Utah coals and the following processes.

Scheme III. For the manufacture of semi-coke in slack sizes form sub-bituminous Utah coals, the Hayes process is considered to be the most suitable. The Wisner process may also be suitable on the basis of confidential cost data...

Notes ~

The foregoing opinions and conclusions are formulated upon the basis of information and data presented in this report. Changing economic conditions and advances in LTC technology may in time necessitate important revisions of these opinions and conclusions.

Processes not named in this report as being the most suitable for Utah coals under the economic conditions pertaining thereto, may be most suitable for other coals in other localities. Comments concerning these processes are made in a general way, and it is neither the desire not the intention of the Foundation to being discredit to any inventor or company controlling these processes.

LTC is a field of human endeavor that is replete with conflicting ideas and opinions both as to its economic feasibility and the relative advantages and disadvantages of its processes. Be this as it may, we believe that a sound basis has now been laid for the initiation of LTC in Utah. In order that comparable and detailed analyses may be made following publication of this report, we trust that essentially the procedures as herein set forth will be followed.


Chapter 15

The Proposed Erection & Operation of a Semi-Commercial Plant

As pointed out in Chapter II, the sound initiation of LTC to any given set of coals and economic conditions should be carried out according to a systematic plan based upon past experience of the industry. Upon the basis of the foregoing conclusions and according to the above-mentioned plan, we therefore recommend as the next logical step in the development of LTC of Utah coals, the erection and operation of a semi-commercial plant using retorts of commercial size. The plant should be operated continuously for at least one year in order to:

(1) Adequately determine the nature and the extent of profitable markets for semi-coke, (a) in various sizes from slack to pea or somewhat larger sizes, and in briquetted form for use in all existing types of hand-fired combustion equipment, and (b) in slack sizes for use in all existing types of stoker-fired combustion equipment.

(2) Accurately determine the operating costs for the carbonization methods employed, which thus far have been estimated on the basis of previous experience with installations in other localities and with other coals.

(3) Determine the commercial yields of products for each of the systems employed. These data have been obtained previously with Utah coals in carbonization equipment of an experimental scale.

(4) Determine the best operating technique for each of the systems employed from the standpoint of technical and economic considerations.

(5) Develop profitable markets for the tar, light oil, and fuel gas.

In conjunction with the semi-commercial plant, an adequate research laboratory should be provided in order to:

(1) Insure that the operating efficiency of each of the carbonization systems is maintained constant and is as high as possible.

(2) Insure that the quality of each product is maintained constant and that it meets the specifications required for its most profitable sale.

(3) Establish a proving-ground for ideas and methods to improve upon the operation of the plant.

(4) Scientifically investigate the properties of the tars in order to develop new products which will find a profitable and ready market. For tangible results, research of this nature should be conducted continuously over a period of several years.

After one year of continuous operation of the semi-commercial plant, it is hoped that the most efficient and economic process of those names herein could be adequately determined. Also it is hoped that sufficient information would be available from which to judge whether or not a commercial plant should then be erected. Research work on the tars should be conducted continuously over a period of several years. Also it would be well to conduct additional studies of Utah coals in order to learn more of their properties and uses.

Processes To Be Used In Semi-Commercial Plant ~

In order to carry out the above-named objectives by the operation of a semi-commercial plant, combinations of the most suitable processes herein before named, may be made according to the following plans:

Plan I. The Hayes and NFC processes may be used in order to minimize the amount of money required for the plant. Briquettes could then be made by each process and their respective properties and uses determined. Semi-coke in various sizes from slack to pea could be made by the NFC method. Also, semi-coke in slack sizes could be made by the Hayes process.

Plan II. The Hayes, NFC and Rexco processes may be used. In addition to the operation of the Hayes and NFC processes for the purposes named under Plan I, semi-cokes in various sizes could be made by the Rexco and NFC methods and their respective properties and uses determined.

Plan III. The Hayes, NFC and Wisner processes may be used. In addition to the operation of the Hayes and NFC processes for the purposes named under Plan I, semi-cokes in slack sizes for stoker use could be made by the Hayes and Wisner processes and their respective properties and uses determined.

Plan IV. The Hayes, NFC, Rexco and Wisner processes may be used. In this way, the technical and economic feasibility of all of the most suitable processes could be determined together.

For each of these Plans, a common condensing and gas-scrubbing system could be employed.


Part VI

Apparatus & Procedures Used for Conducting Laboratory Investigations & Carbonization Studies

Chapter 16

Sampling Coal At The Mine

Problems ~

The general problems that were considered in the sampling and preparation of coal samples at the mine are given below:

(1) The sample must be taken and prepared so that it is as representative as possible of the coal being mined.

(2) Sufficient coal must be obtained in order to carry out all of the tests required with one sample, otherwise all data cannot be correlated practicably.

(3) The greatest possible percentage of large-size coals should be obtained thereby preventing excessive oxidation of the coal during handling.

(4) The sample must be prepared for shipment to the laboratory in a manner that will prevent oxidation of the coal, otherwise its carbonizing characteristics may be altered.

Method ~

The US Bureau of Mines has adopted a procedure for the sampling of coal at the mine for carbonization studies. This method was used as a standard, but was modified slightly to suit our special requirements.

Small samples for chemical analysis and other laboratory tests were prepared in accordance with the standard practice at the Bureau of Mines.

Fieldner, et al.: Method & Apparatus used in Determining the Gas-, Coke- and By-Product-Making Properties of American Coals.; US BM Bull. # 344 (1931).

Holmes, Jos.: The Sampling of Coal at the Mine; USBM T.P. # 1 (1911)

Fieldner, A.: Notes on the Sampling & Analysis of Coal; USBM T.P. # 76 (1914)


Chapter 17

Modified Agde-Damm Plasticity Test As Applied To Utah Coals

Object ~

This test was carried out for each coal in full accordance with the method outlined by Brewer and Atkinson. Object of the test is given by these writers as follows:

"This ‘expansion test’ indicates the plastic properties of a coal by measuring the linear expansion and contraction which a small cylindrical briquette of coal undergoes while being heated to 500° C (932° F)."

Apparatus ~

Figure A1 shows a vertical section of the apparatus which was a duplication of that used by Brewer and Atkinson except that the dimensions of the copper block were altered to fit the heating chamber of a Koskins type Volatile Furnace. Figure A2 shows the assembled apparatus.

Figure A-1 ~ Agde-Damm Plasticity Apparatus

Procedure ~

Two coal briquettes were formed by compressing 0.7 gram samples of minus 60 mesh coal in 7.6 cm glass tubes of 0.8 cm bore at 10.3 kg/sq cm (146 psi). The lengths of the finished briquettes (approx. 1.8 cm) were then carefully measured and the tubes inserted in the 1.1 cm holes in the copper heating block. One briquette was allowed to expand freely during the test. The second briquette supported a total weight of 500 gr, represented by the assembly shown in Fig. A2. The micrometer distance gauge was arbitrarily set to register the measured length of this coal column. The changes in length of the column during a test were indicated directly by the gauge readings.

The coal charge was heated at a rate of 4.8° plus or minus 0.2° C per minute. Temperatures were measured by thermocouples in the hollow-rod plunger and copper block. Gauge and temperature readings were taken and recorded at 5-minute intervals up to 270° C and at 22-minute intervals thereafter, until the end of the run at 500° C. It was actually advisable to take additional readings at 1-minute intervals near the critical temperature points (where the change on the distance gauge was from contraction to expansion, or vice versa) and elsewhere in the test where the rate of gauge movement was rapid. A small electric buzzer was used to tap the gauge before each reading, except when the rate of change was quite rapid.

Upon completion of the test at 500° C, the free expansion sample was removed from the furnace, allowed to cool, and its length measured again.

Corrections ~

Two predetermined sets of corrections were applied to eliminate the effect of the thermal expansion for the instrument and to obtain the "true" coal temperatures. Corrections for the thermal expansion of the instrument from room temperature to 500° C were predetermined from gauge readings in blank runs in which a cylindrical block of quartz was substituted for a coal briquette of like dimensions. These readings were subtracted from gauge reading at corresponding temperatures observed in regular tests. Temperatures made in the center of the coal charge in separate runs gave data to correct the lower plunger and higher block temperatures regularly observed in test runs.

Results ~

A plasticity curve was drawn for each of the coals by plotting the change in the length of the coal column with the corresponding temperature readings.

From each of these curves a figure was obtained which we have chosen to call the plasticity value. We believe that this value may be used to indicate the coking characteristics of any Utah coal. A discussion of the method used to determine the plasticity value and its application, appears in the body of the report.

Also from the plasticity curves, certain data were obtained according to the following standard definitions:

(1) The initial contraction temperature is the temperature at which the sample begins to contract due to fusion and softening of the coal particles.

(2) The initial expansion temperature is the temperature at which active rapid decomposition of the coal commences, and this is indicated by the sudden expansion of the coal. In the case of most Utah coals, this expansion does not occur. If the particles of coal do not coalesce, the distillation products escape without causing swelling.

(3) The final expansion or solidification temperature is the temperature at which expansion ceases abruptly and at which the material sets into a rigid cellular mass.

(4) The plastic range is the temperature interval between the initial contraction temperature and the final expansion temperature.

(5) The swelling coefficient is the ration of the final length to the initial length of the briquette which is allowed to expand freely.


Chapter 18

Agglutinating-Value Test As Applied To Utah Coals

The method found to be most satisfactory for Utah coals and adopted as a standard for all agglutinating tests made in this investigation followed closely by the procedure employed by the USBM and proposed by the American Society for Testing Materials.

A representative sample of 200-mesh coal was intimately mixed with Ottawa sand carefully cleaned and graded to minus 45-plus 60 mesh. The mixture weighted 20 gr, and the ration of sand to coal was 8 to 1.

The mixture was carefully transferred into a special cylindrical crucible, compressed for 30 seconds under a load of 3.5 kg, and then carbonized in a standard Fieldner volatile furnace at 650° C (1202° F) for 20 minutes.

The sand-coke button thus obtained was crushed in a compression testing machine which was applied to the load at a constant rate. The load required to crush the button was determined in kilograms and reported as the agglutinating value of the coal. Six buttons were tested for each sample of coal, and if one or more buttons had crushing strengths varying more than 10% from the average, a new set of buttons was prepared and tested.

For the determination of agglutinating values of blends of coking and non-coking coals, and also for mixtures of coal and tar-oil, the combined weight of the blend or mixture was made equal to the weight used for coal alone. In this manner, the proportion of sand was the same in every case, as was also the total weight of the button.

Modification of the standard procedure with respect only to the sand-coal ratio and the carbonization temperature, was necessary in order to produce a sufficiently strong and uniform button from Utah coals. Instructions for carrying out the details of this test are given in the reference cited.

Selvig, W., et al.: Agglutinating Value Test for Coal; ASTM Proc. 33: 741 (1933).


Chapter 19

Apparatus & Procedure For Conducting Carbonization Studies

Sampling & Preparing Coal for Tests ~

Preparation of 2500-lb Sample: A 2500 lb sample as received from the mine in the 55-gallon steel drums was spread on a clean concrete floor, and plus 3" lumps were placed in a common pile. These lumps were then broken up to minus 3" pieces with the minimum production of fines, and were then placed with the remaining coal. The entire sample was next thoroughly mixed by careful shoveling to form a conical pile. This operation was continued until the larger lumps were evenly distributed throughout the mass. The sample was then formed into a long ridge by spreading shovelfuls in a thin uniform layer and in a straight line on a clean concrete floor. Not more than 5 lb of coal were shoveled at one time. Each shovelful was spread uniformly beginning at the end of the preceding one until the pile had a length of about 20 ft and a width equal to the width of the shovel. The succeeding shovelfuls were then spread over the first thin layer of coal but in the opposite direction. This procedure was continued with occasional flattening of the pile, until the complete sample had been spread.

The coal was then placed in the drums according to the following method: Beginning on one side and at one end of the pile, and shoveling from the bottom, one shovelful was removed and placed in drum 1; then a second shovelful was taken from along the side of the pile at a distance equal to the width of the shovel in drum 2; a third shovelful was placed in drum 3 and so on until the entire sample was transferred to the drums. The sampler always advanced in the same direction around the pile so that its size was reduced gradually and in a uniform manner.

The lids of the drums were then carefully replaced with a well-fitting gasket and clamped securely. Each drum was properly identified.

Preparation of Retort Charge ~

The 25-lb standard retort charge was prepared in the manner described below.

A sufficient sample of coal was taken from the air-tight containers and screened according to the following sizes and weights:

Minus 1-1/2", plus 1" -- 15 lb (approx.)
Minus 1", plus ½" -- 5 lb (approx.)
Minus ½", plus 4 mesh -- 5 lb (approx.)

Half of the plus 1" sample was then placed in a wooden box. The 5 lb sample of the plus 4-mesh coal was next placed on top, whereupon the box was shaken gently until the small coal had filled the voids between the lumps. The remaining half of the lump material was placed in the box, followed by the 5 lb sample of plus ½" coal. Again the box was shaken gently until mixing was completed.

Following this procedure, the sample was leveled off and measurements were taken to determine its volume and weight.

Carbonization Studies With Experimental Plant ~

Description of Apparatus: A vertical static retort and a horizontal rotating retort were employed for the carbonization studies. Provision was made to heat both retorts externally b an electrical heating element wound on the outside retort surface, and internally by the use of superheated steam. Retort temperatures were carefully controlled with the aid of thermocouples placed as shown in Fig. A-3, A-4 & A-9. Distillation products were collected in the condensing and scrubbing train shown in Fig. A-3, A-4, A-5, & A-9. Plant controls were centralized at one common location shown in Fig. A-11.

Figure A-3 ~ Schematic Layout Experimental plant, LTC with Static External Heating
Figure A-4 ~ Schematic Layout Experimental plant, LTC with Static Internal Heating

Static Retort: The static retort shown in Fig. A-3, A-4 & A-5 consisted of a 6 ft length of 5" seamless steel tubing. With the exception of the lower 4", the tube was insulated and encased with a sheet-metal cover 23" diameter.

Sealing was accomplished by fastening a circular steel plate over each end of the retort. The cover-plates were ¾" thick with a circular groove cut in one face to fit the chamfered ends of the retort. A suitable packing was placed in the grooves to provide an air-tight seal. Each cover-plate was drilled to receive three holding bolts welded to the sides of the retort tube at each end. The plates were tightened in place by nuts.

Interchangeable top cover-plates were provided; one for use when heating externally, and the other for use when carbonizing with superheated steam. For external heating the plate was provided with a 1" vapor takeoff. When using steam to plate was plain without opening. Interchangeable bottom plates were also provided. When heating externally, the bottom plate was fitted with a sheet metal disk to support the coal charge 12" above the bottom of the retort. The disk was fitted loosely in the bore of the retort tube. When using steam, another cover plate was fitted with a similar coal-supporting disc which was perforated to allow the distribution vapors and steam to travel downward to a deflecting disc 5" below. This arrangement prevented the coal from being in contact with the cooler bottom end of the retort tube. In the side of the tube, and midway between these two discs when placed in position, there was provided a 1" vapor outlet. Similarly, 2" below the top of the retort tube, there was provided a ¾" steam inlet. These two openings were plugged when using external heating.

The electrical heating coil was wound on alundum cores surrounding the retort from a point 6" below the top of the tube to a point 12" above the bottom, thus providing a heated length of 54 inches. The electrical resistor consisted of a single helix of 11 gauge Ni-Cr alloy wire and was supplied with 220 V single phase current. Carbonizing temperature was controlled with a switch manually operated according to the retort temperatures indicated by the thermocouples (TC) shown in the figures. Properly insulated connections were provided at the top of the retort tube for a pressure gauge and for supplying either superheated steam from the gas-fired superheater shown in Fig. A-4, or saturated steam from the steam supply line. Saturated steam was used to cool the retort and the carbonized residue when using superheated steam for heating.

Rotary Retort: The rotary retort assembly shown in Fig A-9 and A-10 was composed of three concentric welded sheet-steel cylinders comprising the outer shell, the heating chamber, and the coal retort or cylinders. The coal cylinder, 10" diameter and 3 ft 10" long, was coiled from 16-gauge sheet steel with one end closed by a plate of the same material. In the center of this pipe there was provided a thermocouple well made of 1/8" black iron pipe. The outer end extended 7" beyond the end of the cylinder and the inner end terminated at the inside surface of the cylinder wall midway between the ends. The other end of the coal cylinder was provided with an insulated lid having an outer flange which was bolted to a corresponding flange on the cylinder with a gasket between, thus sealing the lid to the cylinder. Welded to the inside face of the lid and filled with insulation was a thin sheet steel cylinder 6" long of suitable diameter to allow a loose fit inside the coal cylinder. A 1" pipe serving as a vapor outlet was fitted in the exact center of the lid and extended through the inside end of the insulated cylinder. A baffle plate having a perforated center portion was fitted to the inside of the lid and at a distance away from it so that the coal charge was prevented from coming into contact with the relatively cold surface of the lid, but a the same time permitted the distillation vapors to pass freely out of the retort.

The heating chamber or cylinder was rolled from 12-gauge sheet steel. It was 4 ft 3" long with a suitable diameter to permit the coal cylinder to slip easily inside. On the outside of this heating cylinder and for a length of 3 ft 4", an electrical heating coil was wound having essentially the same current carrying capacity as the heating element used for the vertical retort. A 3/8" layer of furnace refractory cement was used as an insulator. A 3" length of 1/8" black iron pipe welded midway along the outside surface of the heating cylinder served as a thermocouple well. To the open end of this cylinder was bolted a 3/16" steel plate annulus, 22" in outside diameter and 11" inside diameter, which formed one end of the outside shell or cylinder. On this annulus were also provided three equally spaced lugs which held the coal cylinder rigidly in place inside the heating chamber. The opposite end of the heating cylinder was supported on lugs welded to a similar 3/16" steel plate forming the other end of the outside shell. This arrangement permitted the end of the heating cylinder to slide on the lugs as elongation during heating and prevented excessive strains from being induced.

The outside shell or casing was rolled from 12-gauge sheet steel. This cylinder, 22" in diameter and 4 ft 4-1/2" long, encased the heating cylinder and in the space between the two, asbestos-magnesia insulation was firmly packed. A thin steel plate in the heating cylinder and 5" from the end supported by lugs, prevented the insulation from working into the inside of the heating chamber. A 1" pipe was provided in the center of the plate and extended through the center of the end plate of the outside shell. This permitted the thermocouple well, in the coal cylinder described above, to extend out through the end pate of the outside cylinder.

The retort assembly was supported on and driven at a constant speed of 2.5 rpm by 4 rollers engaging with two heavy, V-grooved rings spot-welded near each end of the outside shell. The roller shafts were driven with a 1/8 hp electric motor. Suitable speed reduction was obtained by the use of a worm gearing integral with the motor, a V-belt counter-shaft, and roller chain and sprockets. Current was supplied to the heating coil through slip rings mounted on one end of the outside shell. Similar slip rings were provided for thermocouple leads. For heating with superheated steam, the thermocouple well in the coal cylinder was replaced with a 9" length of ½" pipe which extended out through the 1" pipe protruding from the center of the end plate of the outside shell. Superheated steam was admitted to the retort through this ½" pipe by means of a rotating slip joint. A similar slip joint was used on the retort vapor outlet line.

Condensing & Scrubbing Train: The condensing and scrubbing train for recovery of the volatile by-products is shown diagrammatically in Fig. A-3, A-4 & A-9, and photographically in Fig. A-5. The same train was used for both the vertical and the rotary retort.

The distillation products passed from the retort offtake to the air-cooled Condenser 1, made of a 4" vertical pipe, 51 inches long with a length of 2" pipe concentrically located within the larger pipe and passing through a tee at the top to within 1-1/2" of the bottom. The arrangement was such that the vapors of distillation passed downward through the 2" pipe to the bottom and then passed upward through the annular space and thence out of the tee at the top. A condensate drain cock was provided at the bottom. The gas was then passed to the multi-stage water-cooled Condenser 2, and then to the single-pass water-cooled Condenser 3. Next in line was placed a tar-fog filter made of a sheet metal cylinder, 10" in diameter and 18" long, filled with rock wool and arranged internally with baffle plates to twice reverse the direction of the gas.

The detarred gas first passed upward through a 4" lead tower, 5 ft high, supplied with 4-normal sulfuric acid for removal of ammonia; thence through a 5" cast iron tower, 5 ft high, supplied with 4-N caustic liquor for removal of hydrogen sulfide; and finally through a similar tower supplied with wash oil for removal of light oil. The scrubbing liquors and wash oil in the towers passed through perforated distributing plates in the tower tops and descended counter-current to the gas stream through the tower packing which consisted of broken pieces of stoneware rings. The liquors and oil left the tower bases through liquid seals and were received in 2-gallon bottles.

Meters & Gas Sampling: Upon leaving the scrubbing towers, the gas passed through Meter 1, and thence to the suction side of a small compressor. A needle valve placed in the line between Meter 1 and the compressor, controlled the suction placed upon the condensing system. All the gas was compressed to about 40 psi. A sample was passed into a gas-sampling tank of about 1-1/4 cu ft capacity, and the remainder was sent through a regulating valve to Meter 2, and thence through a waste line at the exit of which the gas was burned. The rate of sampling was controlled by the rate of displacement of wash oil with which the sample tank was filled at the beginning of each test.

Measuring Apparatus: Temperatures throughout the experimental plant were measured by thermocouples at the positions indicated on Fig. A-3, A-4, & A-9, for the two types of retorts and two methods of heating. Chromel-alumel couples were used together with insulated alloy extension leads and two 10-point selective switches, shown on the control panel in Figure A-11. With the use of a double range potentiometer, thermocouple readings were recorded at intervals of 15 minutes.

The apparatus was designed for a slight vacuum throughout the condensing and scrubbing train. Manometers paced on the control panel shown in Fig. A-11 were connected with small copper tubing to the points in the train indicated on Fig. A-3, A-4, & A-9. Vacuum on the air-cooled Condenser 1, was maintained at approximately 5" of water. All pressures were recorded at 15 minute intervals during a test.

The gas volumes indicated by the calibrated Meters 1 and 2 were recorded every 15 minutes. The total volume was determined by adding the amount passing through Meter 2 and the calculated amount contained in the sample tank at the end of the test. Meter 1 served as a check. This arrangement permitted Meter 2 to operate under a very slight, constant and positive pressure regardless of the possible pressure fluctuations in the condensing and scrubbing train which fluctuations would, of course, affect the accuracy of Meter 1.

When superheated steam was used as a heating medium, the steam condensate from Condenser 3 was caught in a decanter which separated the condensate from the tar. The tax-free water was then continuously run into a tank where its total weight was determined.

Test Procedure ~

Vertical Retort, Slow External Heating: For these tests, the retort was first heated to 300° C plus or minus 5° C, as indicated by TC #1, Fig. A-3. While this was being accomplished fresh solutions were provided for the scrubbing towers, the towers were flushed to thoroughly wet the packing, the condensing and scrubbing train was checked for leaks and the settings of all valves in the train were checked. When the above temperature was reached, the heating current was turned off and an initial set of readings of all TCs and gas meters was taken. The prepared coal sample was then quickly charged into the retort to a point within 6-1/2" of the top and the lid was bolted into place and the vapor line connected. When carbonizing bituminous coals only, a small chain was used to facilitate discharge of the semi-coke, particularly when made at the lowest carbonizing temperature. The chain was supported in the center and extended the full length of the retort. After quickly placing the insulation on the top of the retort, the compressor was started, the heating current turned on, and a vacuum of 5" water was established on the air-cooled Condenser 1. A complete set of readings was then taken and repeated thereafter every 15 minutes. To aid in plant control, curves of the temperature changes and gas evolution were plotted against time. When the gas escaping from the waste gas outlet could be ignited, the time was noted and recorded, the meters read, and the gas sampling started. The heating was continued up to a predetermined carbonizing temperature (450°, 550°, 650°, 750°, or 850° C) which was maintained throughout the remainder of the test by adjusting the supply of current to the retort. Carbonization was judged to be complete when the gas evolution ceased. After cooling overnight, the shrinkage of the semi-coke was measured and the retort was discharged carefully to prevent excessive breakage. Meanwhile the tower solutions were weighed, sampled and analyzed. Also the room temperature and the pressure of the gas in the sampling tank were recorded for the purpose of calculating the gas volume. The tar and liquor were recovered using live steam to drive out tar adhering to the condenser surfaces. Table A-1 presents a sample data sheet, and Fig. A-6 shows temperature and time for a typical test at 650° C.

Rotary Retort, Slow External Heating: For these tests, the retort heating chamber was first preheated to about 415° C as indicated by TC #18, Fig. A-9. Then the coal-containing cylinder, previously charged with the standard 25-lb coal sample, was inserted into the heating chamber. The vapor outlet connection was made, TC # 17 was connected, and the retort driving motor was started. Charging the cold coal container into the preheated chamber lowered the temperature of the latter to a minimum of about 325° C in approximately 30 minutes. This procedure gave the same temperature time results as those obtained with the procedure used for charging the vertical retort. The preliminary preparation of the plant and the procedure from this point to the end of the test was the same as that used with the vertical retort. When carbonization was complete, the coal cylinder was removed from the heating cylinder and allowed to cool. Table A-4 is a sample data sheet and Fig. A-12 shows temperature and time records of a typical test at 650° C.

Vertical & Rotary Retorts, Rapid External Heating: The procedure for the rapid heating tests conducted at 650° C was the same as for the corresponding slow heating tests, except that the vertical retort and the heating chamber of the rotary retort were heated to approximately 700° C before charging. Tables A-2 and A-5 are sample data sheets, and Fig. A-7 and A-13 show temperature and time records for vertical retort and rotary retort tests respectively.

Vertical & Rotary Retorts, Internal Heating With Superheated Steam: For tests with superheated steam, the coal was charged with the retort or heating chamber at about 1000° C. Superheated steam at 5 psi and at a predetermined temperature was then admitted to the retort. When using the vertical retort, superheated steam was supplied until the retort wall, as indicated by TC # 4, reached a temperature about 100° C below the temperature of the entering steam. Saturated steam was then admitted to quench the semi-coke and was continued until the evolution of combustible gas ceased. The procedure with the rotary retort was similar, using TC # 18 for the retort wall temperature. The operation of the remainder of the plant was similar to the method used with external heating, except that the temperature of the cooling water to Condenser 2 was high enough to prevent heavy tar fractions from clogging the condensate lines and at the same time low enough to condense all the steam. The total steam, both superheated and saturated, was measured in the condensate tank. Table A-3 is a sample data sheet and Fig A-8 shows temperature and time records of a typical vertical retort test using superheated steam at 650° C.

Table A-3 ~ Sample Data Sheet
Figure A-8 ~ Vertical Retort Test w/ Superheated Steam

Determinations of Yields & Examinations of Products ~

Semi-Coke Yield: The semi-coke was discharged from the retort into a sheet-steel container by means of a metal chute so that after discharge, it laid in the same relative position that it had occupied in the retort; that is, the top portion of the charge was at one end and the bottom was at the other. Six lumps of the carbonized material were so chosen as to represent all portions of the charge and were weighed and set aside for photographing. The remainder of the charge was placed in a tared wooden box and its volume and weight were determined and recorded. The sum of the weight of the photographic ample and the weight of this portion was reported as the yield of semi-coke. A screen analysis was then made using square mesh screens of 1", ½", and 4-mesh sizes.

Shatter Tests: All of the semi-coke remaining on the 1" screen used in the screen analysis was taken as a sample for shatter tests to determine mechanical strength or stability of the semi-coke. These were conducted in accordance with the ASTM method which specifies a drop of 6 ft to a steel plate, except that a smaller sample was used than prescribed, and a hinged-bottom box was used which was 12" sq and 8" deep.

(Am. Soc. Testing Materials Standards Pt 2, p. 449, Designation D 141-23 , 1939)

The ratio of the plus 1" semi-coke remaining after the fourth drop, to the total weight of the original sample of plus 1" semi-coke, was determined and recorded as the mechanical strength or stability of the fuel.

Samples for Chemical & Ignition-Temperature Tests: The semi-coke used for the shatter test was combined with the remaining semi-coke, and the whole was crushed to pass a 4" screen. It was then riffled until two equal samples of approximately 2 lb each remained. One of these samples was set aside in a properly labeled container for ignition temperature tests. From another 2-lb sample, a 50 gr moisture sample was obtained by riffling. The remainder of this sample was crushed to pass a 60-mesh screen and by riffling, a 50-gram sample for proximate and ultimate analyses and, also, a 100-gr sample for determining ash-softening temperature were obtained.

Chemical Tests: Proximate and ultimate analyses, including calorimetric tests, were made... [and] the ash-softening temperatures were determined...

Photographic Records: The semi-coke specimens were photographed on top of a ½" grid lines and at the same distance from the camera so that the relative sizes of the lumps may be compared directly.

Ignition Temperature Test: A representative 2-lb sample of coal or coke was crushed to pass an 8-mesh screen. The portion of the sample retained in a 20-mesh screen was quartered until a representative portion of 3 oz was obtained for the ignition test. The discarded quarters were returned to proper containers for use in case check analyses were required. The portion of the sample passing the 20-mesh screen was retained on a pan and returned to the original gross laboratory sample. Thus, the sample for ignition-temperature determination was sized from -8 to +20 mesh.

The apparatus used is shown and described in Fig A-14.

To insure accurate temperature observations, the potentiometer was carefully adjusted for temperature and needle deflection corrections. Also, the electric furnace was thoroughly inspected to make certain that all connections were secure, and that the furnace was free from any ash or coke residue that might have been present from a previous test.

In addition, the remaining equipment, namely: two rheostats, wattmeter, chromel and alumel thermocouple (TC), crucible support, bras-wire basket, and galvanized iron stack were checked for serviceability. Any irregularities were adjusted and the apparatus was given a final check before the determination was started.

The prepared sample was placed on a sheet of paper and again thoroughly mixed by raising alternate corners of the paper. Electric current was applied to the furnace with the crucible support, empty basket, and galvanized iron stack in place. The power was admitted at 200 watts and held at that point until a temperature of 175° C was reached.

The current was then cut off and the preheated wire basket was removed from the furnace and charged with a sample weighing 2.5 gr +- 0.2 gr. The charged basket was then carefully lowered into its test position in the preheated furnace, the stack was replaced, and the electric current was applied again.

The power input to the furnace was adjusted to a predetermined wattage, according to the schedule presented below. The temperature of the sample was constantly checked until it reached about 300° C, at which point readings were made every 30 seconds and recorded. This procedure was followed until the sample had ignited and at least 6 observations at 30 second intervals had been noted and recorded after ignition had started.

The usual time required for the complete test was 15 to 30 minutes.

For accurate results, the coke or coal sample should be placed loosely in the wire basket and not tamped, since sufficient draft must be allowed to circulate through the charge to support combustion. The basket for each test should be filled to overflowing and then leveled off before being placed into the electric furnace. Care should be taken to insure that no portion of the sample is lost from the wire basket. Reliable readings cannot be obtained when the basket is partially loaded, because an erratic and rapid combustion of the isolated particles takes place.

Preheating the furnace above 175° C produces a temperature rise in the fuel of greater magnitude than that produced by the combustion of the fuel itself. Thus, the ignition point of the sample cannot be determined with accuracy. Therefore, the furnace should never be preheated above 175° C.

If all precautions are observed faithfully, the ignition temperature of any given sample can be determined within limits of 5° C.

Experience showed that the power input to the furnace is of primary importance to the securing of ignition temperatures that are defined clearly and accurately. Limits of power input to the furnace as set forth in the chart below [Not included here] gave satisfactory results. However, if the power input is varied beyond the specified limits, the observer will encounter difficulties that will make the resulting work of little or no value.

The ignition curve is obtained by plotting the temperature rise of the sample with time according to Fig A-15. A sharp change in the slope of the curve indicated that ignition of the sample had occurred. The temperature corresponding to the intersection of the extensions of the two essentially straight portions of the curve was taken to be the ignition temperature.

Gas ~

Sampling & Determination of Yield: The compressed gas was sampled continuously by placing the sample tank under the delivery pressure of the compressor and allowing the wash oil, with which the tank had been previously filled, to escape through a regulating valve into a drum equipped with a float indicator. The rate of oil displacement was adjusted to parallel the rate of gas evolution.

The total gas evolved was determined by adding the corrected volume of gas indicated by Meter 2 and the calculated volume contained in the sample tank, all reduced to 60° F and 30" Hg and saturated with water vapor.

Chemical Analysis: For the heating-value determination, the compressed gas was transferred from the gas-sampling tank to a small gas holder until the tank pressure was reduced 3 to 5 psi. The calorific value was determined using a Junkers type calorimeter in the prescribed manner.

A sample of the remaining compressed gas was subjected to complete analysis in a USBM type Orsat apparatus. The apparatus and procedure are described in the Gas Chemists’ handbook, 1929 edition, pp 238-246. A further portion of this gas was used for the determination of H2S, NH3, and light oil according to the procedures described below. The calculated heating value was determined using the calorific value of the gas constituents in the US Bureau of Standards Circular C-417 (1938), pg 38. Gas density was obtained using the figures found in Technical Data on Fuel, p. 235 (H. Spiers, 1937).

Ammonia Determination In Liquor from Scrubbing Tower: A 25 ml sample of the liquor was paced in a Kjedahl distilling flask with 250 ml of water and 25 ml 15% NaOH solution. A 500 ml Erlenmeyer flask containing 30 ml 1-N sulfuric acid made up to 100 cc with distilled water was placed to receive the distillate. The condenser outlet was beneath the surface of the acid. Approximately 250 ml was distilled over. The excess acid was titrated with 1-N NaOH using methyl orange as an indicator.

Grams per liter of total ammonia = ( 30 ml 1-N NaOH) 0.01703 x 40

In Gas: The gas used in the H2S determination was passed through a second and similar 500 ml Erlenmeyer flask containing 10 ml 1-N sulfuric acid diluted to 200 ml. After the 3 liters of gas had passed through, the flask was removed and the excess acid was titrated with 1-N NaOH using methyl orange as an indicator.

Light Oil Determination In Wash oil From Scrubbing Tower: A 500 ml sample of the oil was placed in a 1 liter distilling flask having 3 necks. The flask was fitted with a stem inlet, thermometer, and an outlet through a packed distilling tube to a Liebig condenser and into a 250 ml separatory funnel. Cork stoppers were used throughout. The still was heated to 150° C with a burner and then superheated steam was introduced. The temperature in the distilling flask was maintained at 145° to 150° C. When 100 ml of water had collected in the separatory funnel, 75 ml was run out. This was repeated until 250 ml had been withdrawn. The remaining water was carefully withdrawn and the oil dried by 10-20 ml of saturated solution of calcium chloride. The dried oil was placed in a dry 125 ml distilling flask fitted with a bead column and condenser. A 50 ml measuring tube was placed to catch the distillate. The distillation was carried to 200° C, giving the light oil.

In Gas: A drying tube and the U-tube with bottom stopcock were placed in the train with the flasks used for the hydrogen sulfide and ammonia determination. Before the gas was passed through the train the U-tube was carefully weighed and immersed in carbon dioxide snow dissolved in acetone. After the 3 liters of gas had passed through the train, the U-tube was removed and the weight of the frozen light oil determined by weighing. The weight was converted to volume by assuming that the light oil had a specific gravity equal to that of benzene.

Tar & Liquor ~

Sampling & Determination of Yield: The combined tar obtained from the 3 condensers from each run was mechanically separated from the liquor as completely as possible. It was then placed in a dehydrating still and heated gradually under a maximum pressure of 60 psi until dehydration was complete. The vapors were condensed and the light oil that distilled over with the water was returned to the dry tar. The yield of tar per ton of coal treated was calculated from the weight of the dry tar thus obtained. Dehydration under the pressures and temperatures used, made possible the complete separation of water without cracking.

The liquor obtained from dehydration was added to the liquor mechanically separated, and the total liquor was reported as percent of coal by weight.

The specific gravity of the dry tar was determined by the pycnometer method carried out in accordance with the ASTM Standards, D70-27, p. 1110, Pt 2 (1936).

Bottoms, sediment and water (BSW) tests were determined using the centrifuge method of the ASTM Standards D96-35, Pt 2, p. 1001 (1936).

The flash point was determined using the Cleveland Open Cup in accordance with ASTM method D92-33, Pt 2, p. 892 (1936).

After carefully straining to remove the sediment, the viscosity of the dry tar was determined using the Saybolt Furol Viscometer in accordance with the ASTM method, D88-36, Pt 2, p. 982 (1936).

The pour point was determined using the "Special Procedure for Black Oils &c." given in ASTM Designation D 97-34, Pt 2, p. 853 (1936).

The heating value and sulfur content of the dry tar were determined using the Parr Peroxide Calorimetric bomb following the method outlined in the Burgess-Parr Company Booklet # 109.

The dry tar was distilled in accordance with the Universal Oil Products Company Method # F-1, outlined in ASTM Designation D 86-35, Pt 32, p. 870 (1936).

The procedure used for determination of tar acids and bases was that of Universal Oil Products Company Method # C-78.

Separation of Tar Acids & Bases in Centrifuge ~

Apparatus: Sharples super-centrifuge, 1 Sharples separator bowl, 1 Sharples clarifier bowl, 2 separatory funnels (2 liter), 1 electric heater, 4 beakers (2 liter), 4 bottles (5 gallon green glass, narrow mouth, cork stoppers);

Reagents: NaOH, (23.5% solution), Sulfuric Acid (10% solution), Chloroform (tech.);

Procedure & Precautions: (A) To remove finely divided carbon: Finely divided carbon and even small particles of coke were obtained in the coal tar. These may be removed from the tar solution by using the clarifier bowl on the Sharples super centrifuge. If the separator bowl was used on a solution containing the finely divided carbon the operation was interrupted due to the plugging up of the spinner openings in the separator bowl.

The solution to be clarified may be the mixture of 23.5% NaOH and tar solution containing the finely divided carbon. That is, the 23.5% sodium hydroxide extracting solution may be added to the coal tar solution before clarification in order to increase the volume or dilute the solution, and to decrease the viscosity of the solution. The amount of tar solidifying on the spouts of the centrifuge is also thereby decreased.

The 23.5%NaOH and tar solution is charged to a 2-liter separatory funnel and is agitated for 15 minutes. The centrifuge machine may be warmed by directing heat rays upon the outside surface from an electric heater. The driving motor is started and the machine is brought up to full speed before introducing the solution to be treated. The clarified solution may be received in a 2-liter beaker. The solution remaining in the centrifuge may be drained and added to the clarified solution since the finely divided carbon particles remain in the centrifuge clarifier bowl.

The procedure for stopping the machine and draining the bowl is given under (B) below.

(B) Extraction of Tar Acids: Charge approx. 1 liter of tar to a 2-lite separatory funnel. Add nearly one liter of 23.5% NaOH solution. Agitate for at least 15 minutes.

The Sharples super centrifuge is assembled using a separator bowl except in cases in which the tar to be treated contains finely divided carbon. In such a case the clarifier bowl is substituted for the separator bowl and the solution is first clarified as described under (A) above.

Connect a rubber delivery tube to the separatory funnel and then to the inlet tube of the centrifuge. The machine is started and brought up to full speed before feeding the liquid to the machine by gravity. The machine is heated previously to prevent the tar from solidifying in the feed nozzle. The tar acid free tar is obtained separately from the NaOH tar acid solution. When the solutions no longer drain from the spouts the delivery tube connecting the stem of the separatory funnel to the inlet tube of the centrifuge is removed from the inlet tube of the centrifuge. The feed nozzle is removed from the inlet tube of the centrifuge. The feed nozzle is removed and the tinned metal dish is placed beneath the bowl of the centrifuge. The centrifuge is allowed to stop. The liquid remaining in the centrifuge bowl drains into the tinned metal dish as soon as the centrifuge bowl stops rotating. Approximately 280 gr of solution remain in the centrifuge bowl and is stored in a separate storage bottle. The sodium hydroxide tar acid solution is also placed in a separate 5-gallon storage bottle to be treated subsequently.

The machine is disassembled, cleaned, and reassembled.

(C) To Extract Tar Bases: The remaining tar acid free solution is now treated with 50% of its volume of 10% sulfuric acid. When the volume of the tar-acid free solution is small an equal volume of 10% sulfuric acid may be used in order to decrease the percentage of neutral oil remaining in the centrifuge bowl. The sulfuric acid tar-acid free solution is agitated for at least 15 minutes.

The centrifuge is started and brought up to speed. The sulfuric acid tar-acid free solution is delivered to the previously warmed centrifuge machine. The neutral oil solution and the sulfuric acid-tar base solution are received in separate 2-liter beakers.  The neutral oil is stored in a separate container to be tested in the laboratory. The sulfuric acid-tar bases solution is stored in a separate 5-gallon bottle. The solution remaining in the centrifuge bowl is caught in the metal dish and is stored in a separate storage bottle. The machine is taken apart. The machine parts and apparatus are cleaned with chloroform.

Ammonia in Liquor: A 25 ml sample of the liquor was placed in a Kjeldahl distilling flask with 250 ml of water and 25 ml of 15% NaOH made up to 100 ml with distilled water was placed to receive the distillate. The condenser outlet was beneath the surface of the acid. Approximately 250 ml was distilled over. The excess acid was titrated with 1-N NaOH using methyl orange as an indicator.

Grams per liter of total ammonia = (30 ml 1-N NaOH) 0.01703 x 40.


Part VII

Review of US Patents Covering Processes & Apparatus for LTC

The following patent claims [Not included here] are quoted verbatim from the US patents covering processes and apparatus for LTC of solid carbonaceous materials [to 1939].

This material is intended as a ready source of information for those who may wish to investigate the patents...

Bituminoil: USP # 1,976,816, App. for Distilling Carbonaceous Material (James Vandegrift & Carl Postel, Oct 16, 1934); USP # 1,995,873, Retort (Vandegrift & Postel, March 26, 1935); USP # 2,041,882, Retort (Vandegrift, May 26, 1936); USP # 1,916,900, Method of Low Temperature Distillation (Vandegrift & Postel, July 4, 1933); USP # 2,041,883, App. for Producing Fuel (Vandegrift & Postel, May 26, 1936); USP # 2,066,082, App. for Producing Fuel (Vandegrift & Postel, Dec. 29, 1936); USP # 2,066,083, Fuel & Method of Producing Said Fuel (Vandegrift & Postel, Dec. 29, 1936).

Carlton: USP # 1,980,245, Retort for LT Distillation (Addy, et al, Nov 13, 1934).

Coalene: USP # 1,710,070, Still (Elmer Records, April 23, 1929); USP # 1,843,174, Coal Distillation App. (Records, Feb 2, 1932); USP # 1,884,017, Process of Distillation of Coal (J. Louttit & Records, Oct 25, 1932).

Coalite: USP # 1,687,989, Retort (Ch. Parker, Oct 16, 1928); USP # 1,687,990, Distillation of Coal (Parker, Oct 16, 1928); USP # 1,687,991, Distillation of Coal (Parker, Oct 16, 1928); USP # 1,689,152, App. for Distillation of Coal (Parker, Oct 12, 1928); USP # 1,754,693, Retort (Parker, April 15, 1930); USP # 1,827,800, Closure Mechanism for Retort Doors (Parker, Oct 20, 1931); USP # 1,860,591, Retort (Parker, May 31, 1932); USP # 2.014,583, App. for Distillation of Coal (Parker, Sept 17, 1935); USP # 1,989,459, Retort (Parker, Jan 29, 1935).

Davidson: USP # 1,831,704, Rotary Retort for Treatment of Oil Shale (Th. Davidson, Nov 10, 1931).

Derby-Horner: USP # 1,948,515, Method of Carbonizing (Ira Derby & H. Horner, Feb 27, 1934); USP # 2,029,759, App. for Treatment of Carb. Material (Derby & Horner, Feb 4, 1936); USP # 2,029,760, App. for Treatment (Derby & Horner, Feb 4, 1936); USP # 2,029,761, Method of Forming Charges (Derby & Horner, Feb 4, 1936); USP # 2,029,762, Method of Treating Carb. Material (Derby & Horner, Feb 4, 1936); USP # 2,029,763, App. for Treating Carb. Material (Derby & Horner, Feb 4, 1936).

Dobbelstein: USP # 1,690,444, App. for Drying or Smoldering Loose Material (Otto Dobbelstein, Nov 6, 1928); USP # 1,718,542, App. for Drying &c. (Dobbelstein, June 25, 1929); USP # 1,718,543, App. for Drying &c. (Dobbelstein, June 25, 1929); USP # 1,718,544, App. for Drying &c. (Dobbelstein, June 25, 1929).

Dvorkovitz: USP # 1,706,825, Retort (Paul Dvorkovitz, March 26, 1929)

Fenton: USP # 1,484,256, Intermittent System for Treatment of Coal (James Fenton, Feb 19, 1924); USP # 1,484,257, Continuous System for Treatment of Coal (Fenton, Feb 19, 1924); USP # 1,484,258, Proc. for Treatment of Coal (Fenton, Feb 19, 1924).

Gibbons/Cellan-Jones: USP # 2,103,620, Coke Oven (G. Cellan-Jones, Dec 28, 1937).

Greene-Laucks: USP # 1,713,840, Method & App. for Carbonizing Coal (Irving Laucks, May 21, 1929); USP # 1,723,932, App. for Carbonizing Coal (Fr. Greene, Aug 6, 1929); USP # 1,730,569, App. for Extracting Values (Greene, Oct 8, 1929); USP # 1,854,300, Method & App. for Carbonizing Coal (April 19, 1932); USP # 1,890,661, App. for Carbonizing Coal (Greene, Dec 13, 1932).

Hayes: USP # 1,595,933, Reverse Gearing (Ch. Hayes, Aug 10, 1926); USP # 1,595,934, Proc. for Carbonization (Hayes, Oct 10, 1926); USP # 1,662,575, Conveyer (Hayes, March 13, 1928); USP # 1,810,828, Method of Carbonizing Coal (Hayes, June 16, 1931); USP # 1,881,826, App. for Carbonization (J. McQuade, Oct 11, 1932); USP # 1,884,379, Carbonization Device (Fr. Tenney, Oct 25, 1932).

Hird: USP # 1,530,986, App. for Carbonization (H. Hird, March 24, 1925).

Holcobami: USP # 1,636,975, Retort Oven for LTC (P. Zuyderhoudt, July 26, 1927); USP # 1,968,896, Retort Oven (J. Mage, Aug 7, 1934); USP # 1,975,621, Retort Oven for LTC (J. Schafer, Oct 2, 1934).

Hood-Odell: USP # 1,926,058, Process of Purifying Gas (Sept 12, 1933).

Illingworth: Re. # 17,572 (USP # 1,645,861), App. for Manufacture of Carbonized Fuel (S. Illingworth, Jan 28, 1930); USP # 1,716,726, Agitating System (Illingworth, June 11, 1929); USP # 1,716,727, App. for Cooling of Coke (Illingworth, June 11, 1929); USP # 1,800,633, App. for Manufacture of Carbonized Fuel (Illingworth, April 14, 1931); USP # 1,861,345, App. for Manufacture of Carbonized Fuel (Illingworth, May 31, 1932); USP # 1,895,798, App. for Feeding Coal (Illingworth, Jan 31, 1933); USP # 1,923,209, Plant for Carbonization of Coal (Illingworth, Aug 22, 1933).

Jenson: USP # 1,734,970, Proc. & App. (James Benson, Nov 12, 1929).

Karrick: USP # 1,832,219, Proc. & App. for Superheating Steam (Lewis Karrick, Nov 17, 1931); USP # 1,894,691, Destructive Distillation (Karrick, Jan 17, 1933); USP # 1,899,154, Valve (Karrick, Feb 28, 1933); USP # 1,901,169, Distillation (Karrick, March 14, 1933); US # 1,906,755, Method of LTC (Karrick, May 2, 1933); USP # 1,913,395, Underground Gasification (Karrick, June 13, 1933); USP # 1,923,213, Proc. & App. for Carbonizing Coal (Karrick, Aug 22, 1933); USP # 1,938,596, Retort (Karrick, Dec 12, 1933); USP # 1,942,650, App. for Coking Bituminous Liquids (Karrick, Jan 9, 1934); USP # 1,945,530, Destructive Distillation (Karrick, Feb 6, 1934); USP # 1,950,558, Proc. for Production of Gas &c. (Karrick, March 13, 1934); USP # 1,958,918, Proc. of Destructive Distillation (Karrick, May 15, 1934); USP # 2,011,054, Proc. of Destructive Distillation (Karrick, Aug 13, 1935); Re. # 20,392 (USP # 2,011,054), Proc. of Destructive Distillation (Karrick, June 1, 1937).

McEwen-Runge: Re. # 17,181 (USP # 1,481,140), Carbonization of Coal (Samuel McEwen, Jan 1, 1929); Re. # 17,182 (#1,481,140), Method of Carbonization (McEwen, Jan. 1, 1929).

NFC: USP # 2,030,852, Proc. of Distilling Coal (G. Berry & A. Beardsley, Feb 18, 1936); USP # 2,131,702, Coal Processing (Berry, Sept 27, 1938).

Parker: USP # 1,822,541, Retort (R. Parker, Sept 8, 1931); USP # 1,922,321, Method of Extracting (Parker, Aug 15, 1933).

Parr: USP # 1,754,765, Coking Coal (S. Parr & T. Layng, April 15, 1930); USP # 1,827,483, App. for Coking Coal (Parr & Layng, Oct 13, 1931); USP # 1,874,344, (Parr & Layng, Aug 30, 1932); USP # 1,907,568, Proc. for Coking Coal (Parr & Layng, May 9, 1933); USP # 1,907,569, Proc. of Preparing Coal (Parr & Layng, May 9, 1933); USP # 1,909,421, Proc. For Coking Coal (Parr & Layng, May 16, 1933).

Piron-Caracristi: USP # 1,664,483, App. for Absorbing Fluids from Gases (E. Piron, April 3, 1928); USP # 1,664,484, Method of Removing Tar from Gases (Piron, April 3, 1928); USP # 1,701,054, Purifying Gases (Piron, Feb 5, 1929); USP # 1,709,370, App. for Distillation (Piron, April 16, 1929); USP # 1,709,371, App. for Distilling Solids (Piron, April 16, 1929); USP # 1,733,750, Distillation App (Piron, Oct 29, 1929); USP # 1,794,542, Distilling Hydrocarbons (Piron, March 3, 1931).

Reed-Lamie: USP # 1,696,730, process for Distilling Shale (H. Reed & R. Lamie, Dec 25, 1928); USP # 1,927,219, Coal Distilling App. (Reed & Lamie, Sept 19, 1933); USP # 1,980,828, App. & Proc. for distilling Coal (Reed & Lamie, Nov 13, 1934).

Rexco: USP # 1,283,000, App for Removing Oils from Oil-Shale (G. Wallace, Oct 29, 1918); USP # 1,491,290, App for Distilling Oil Shales (D. Davis & Wallace, April 22, 1924); USP # 1,536,696, Proc of Carbonizing (Wallace, May 5, 1925); USP # 1,714,198, App for Treating Oils (Wallace, May 21, 1929); USP # 1,728,582, Carbonizing App (Sept 17, 1929); USP # 1,804,073, Carbonizing App (Wallace, May 5, 1931).

Salermo: Re. 17,251 (USP # 1,541,071), Distillation App (P. Salerni, April 2, 1929); USP # 1,828,683, Distillation (E. Salerni, Oct 20, 1931); USP # 2,069,421, App for Distillation (Salerni, Feb 2, 1937).

Suncole: USP # 1,460,764, Stuffing Box (H. Nielsen & B. Layng, July 3, 1923); USP # 1,518,938, Rotary Retort (Nielsen, Dec 9, 1924); USP # 1,589,417, Rotary Distillation Retort (Nielsen, June 22, 1926); USP # 1,593,333, Process for LTC (J. Garrow, July 20, 1926); USP # 1,605,761, Treatment of Carbonaceous Material (Nielsen, Nov 2, 1926); USP # 1,654,942, Proc of Making Mixed Gas (Nielsen, Jan 3, 1928); USP # 1,718,830, App for Manufacturing Water Gas (Nielsen, June 25, 1929); USP # 1,830,884, Distillation of Carbonaceous Materials (Nielsen, Nov 10, 1931); USP # 1,866,262, Distillation (Nielsen, Nov 1, 1932); USP # 1,886,350, Method of Distilling (Nielsen, Nov 1, 1932); USP # 1,905,945, C. Machen, April 25, 1933); USP # 1,908,651, App for Distillation (Nielsen, May 9, 1933); USP # 2,112,401, App for Coking Briquettes (R. Hardy, March 29, 1938).

Sutcliffe-Evans: USP # 1,767,231, Distillation (E. Sutcliffe, June 24, 1930).

Trumble & Ramage: USP # 1,514,113, Proc for Oil Sands (M. Trumble, Nov 4, 1924); USP # 1,555,531, Distillation App (Trumble, Sept 29, 1925);  USP # 1,586,131, App for Producing Solid Fuel (Trumble, May 25, 1926); USP # 1,598,831, Process (Trumble, Sept 7, 1926); USP # 1,651,647, Apparatus (Trumble, Dec 6, 1927); USP # 1,653,137, Removable Cover Construction (Trumble, Dec 20, 1927); USP # 1,659,930, Combined Distilling & Cracking Proc (Trumble, Feb 21, 1928); USP # 1,667,403, Method of Producing Power (Trumble, April 24, 1928); USP # 1,674,420, Process (Trumble, June 19, 1928); USP # 1,676,675, Process (Trumble, July 10, 1928); USP # 1,704,956, Process (Trumble, March 12, 1929); USP # 1,713,794, Method for Operating Battery of Retorts (Trumble, May 21, 1929); USP # 1,714,963, Process (Trumble, May 28, 1929); USP # 1,724,982, Oil-Cracking Means (Trumble, Aug 20, 1929); USP # 1,725,320, Hydrogenating & Cracking Organization (Trumble, Aug 20, 1929); USP # 1,836,051, Shale Distillation (Trumble, Dec 15, 1931); USP # 1,873,910, Process (Trumble, Aug 23, 1932).

Ramage: USP # 1,516,406, A. Ramage, App & Proc for Distillation of Coal (A. Ramage, Nov 18, 1924); USP # 1,812,372, Process (Ramage, June 30, 1931); USP # 1,926,455, App for LT Distillation (Ramage, Sept 12, 1933).

White: USP # 1,782,556, Coke & Process (A. White, Nov 25, 1930).

Winzer: USP # 1,929,132, App for Carbonization (C. Winzer, Oct 3, 1933).

Wisner: USP # 1,748,815, Rotary Furnace (C. Wisner, Feb 25, 1930); USP # 1,756,896, Coal Ball & Process (Wisner, April 29, 1930); USP # 1,835,128, Carbonizing & Coking Process (Wisner, Dec 8, 1931); USP # 1,967,762, Rotary Retort (Wisner, July 24, 1934); USP # 1,993,198, Method of Thermal Pretreatment (Wisner, March 5, 1935); USP # 1,993,199, Carbonizing App (Wisner, March 5, 1935); USP # 2,080,946, C. Lesher, May 18, 1937).


Part VIII

Selective Bibliographies

Compiled by Helen Mackintosh (Engg Librarian, Univ. of Utah)

Abbreviation of Periodicals, &c Used in Bibliographies ~ [Not included here]

Utah Coals: History, Geology & Resources Mines & Mining, Coal Industry, Research, Processing & Firing Methods, Cancer Caused by Derivatives of Coal Tar.

Oil Shale: Books, Bibliographies, General & Economic, Geology, Mining, Testing & Processing

[Note: The following select references concern only the Processing & Firing Methods, and are presented in condensed form.]

# 421. Anderson, R., et al: Thesis BS, Univ Utah (1935); Karrick LTC Tests.
# 422. Anderson, R.: Thesis MS, Univ,. Utah (1933); Investigation
# 424. Carter, G.: Thesis MS, Univ Utah (1934); Engg Factors
# 425. Carter, G.: Utah Acad Sci Proc 11: 117 (1934); Recent Investigations
# 429. Cowles, H.: AIEE Utah Sectn Meeting (March 22, 1937); Economics of LTC
# 434. Fieldner, A.: NELA Proc 84: 874 (1927); New Developments in LTC
# 438. Jacobsen S. & Carter, G.: Thesis BS, Univ Utah (1933); Engg Factors
# 439. Ibid.: Ind Engg Chem 27: 1278 (1935); Karrick Process
# 440. Ibid.: Mech Engg 57: 305 (May 1935); Karrick LTC.
# 441. Ibid.: Coal Age 41: 148 (April 1936); Karrick LTC.
# 444. Karrick, L.: Mining Rev 36: 11 (July 1934); Demonstration
# 445. Ibid.: 34: 8 (Feb 1932)
# 446. Ketchum, R.: Report of Joint Smoke Abatement Committee... (1932).
# 447. Larsen, W. & Stutz, C.: Thesis BS, Univ Utah (1932); Design of LTC Plant.
# 448. Ibid.: Gas J 225: 484 (Feb 1939); LTC in Utah.
# 449. Mellor, M. & Woodhead, R.: Thesis BS, Univ Utah (1936); LTC.
# 450. Monnett, O.: Chem. Met. Eng 23: 1246 (1920); LTC of Utah Coals.
# 452. Murray, W. & Whitson, R.: Thesis BS, Univ Utah (1936); Utilization of Fine Sizes Smokeless Fuel.
# 453. Ibid.: Western Mining Survey 14: 4 (June 1933); New Process
# 455. Parr, S. & Layng, T.:  USB Mines R.I. # 2278 (1921); LTC of Utah Coals
# 456. Parr, S. & Olin, H.: Sci Amer Suppl 75:252 (Apr 1913); LTC.
# 457. Perrott, G. & Clark, H.: USBM R.I. # 2341 (1922); LTC.

By-Products ~

# 469. Brown, R. & Branting, B.: Ind Eng Chem 20: 392 (1928). See also USBM & Carnegie Inst Coop Bull 35 (1928); Analysis of Karrick LTC Tars.
# 470. Brown, R, & Cooper, R.: Ind Eng Chem 19: 26 (Jan 1927); See also Carnegie Inst & USBM Coop Bull # 31 (1927); Analysis of Karrick LTC Tars.
# 471. Brown, R., & Pollock, R.: Ind Eng Chem 21: 234 (1929); Analysis of Karrick LTC Tars.
# 473. Duder, J. & Hans, W.: Thesis BS, Univ Utah (1937); Road oils from Karrick LTC of Utah coals.
# 474. Eglof, G.: Fuel Conf 1928 Trans 1: 786; Cracking of LTC Tar.
# 475. Frey, F. & Yant, W.: Ind Eng Chem 19: 21 (1927); Analysis of LTC Gases
# 478. Kinney, C., Karrick, L. & Burton, T.: Mining Rev 35: 5, F-14 (1933); Tests on Karrick LTC Tar.
# 480. Schmutz, D.: Thesis MS, Univ Utah (1932); Oil Reserves in Oil Shale & Coal, Utah & Economic Factors of LTC.

Smoke Problem in Salt Lake City ~ [Not included here]

Low Temperature Carbonization (Books & Articles) ~

# 514. Armstrong, John: Carbonization Technology & Engineering;  London, Griggin (1929).
# 524. Lander, C. & McKay, R.: Low Temperature Carbonization; Benn (1924).
# 525. Lewes, V.: Carbonization of Coal; London, J. Allan & Co (1918).
# 526. McCulloch, A. & Simpkins, N.: LTC of Bituminous Coal; London, Witherby (1923).
# 528. Roberts, J.: Coal Carbonization, High & Low Temperature; London, Pitman (1927).
# 533. Wellington, S. & Cooper, W.: Low Temperature Carbonization; Lippincott (124).
# 534. Wiggington, R.: Coal Carbonization; London, C. Thomas (1930).
# 538. Allison, V.: Ind Eng Chem 22: 839 (Aug 1930)
# 539. Armstrong, H.: Chem. Tr. J. 67: 736 (1920)
# 541. Ibid.: Iron Coal Tr. Rev. 102: 156 (1921).
# 545. Audibert, E. & Raineau, A.: Fuel 4: 176, 222, 255, 307, 362 (Apr., Aug 1925)
# 547. Babcock, E.: USB Mines Bull # 89 (1915); ibid., # 221 (1923)
# 552. Ban, Y.: Fuel Soc Jap J 7: 62 (1928)
# 556. Barash, M.: Gas World 109: 129 (1938)
# 564. Bhattacherjee, R.: Amer Gas Assn Proc, p 1216 (1928).
# 567. Blauvelt, W.: Chem Met Engg 32: 925 (1925)
# 569. Bone, W.: Chem Age (London) 34: 163, 197 (Feb 1936)
# 572. Bristow, W.: Fuel Econ 5: 24 (1929)
# 577. Ibid.: Engineer 1532: 595 (Dec 1931)
# 578. Ibid.: Ind Eng Chem 20: 852 (Aug 1938)
# 580. Brooks, H.: Sci Amer 136: 102 (Feb 1927)
# 581. Ibid.: Power 62: 634, 680 (Oct, Nov 1927)
# 582. Ibid.: Power Plant Engg 29: 1087, 1139 (Nov 1925).
# 583. Ibid.: J Franklin Inst 202: 337 (1926)
# 584. Ibid.: Mech Engg 47: 145 (1925)
# 585. Brown, R.: Gas J of Canada, p. 254 (July 1927)
# 589. Brownlie, D.: Ind Eng Chem 28: 629 (June 1936)
# 590. Ibid.: Gas Age 76: 559 (Dec 1935)
# 591. Ibid.:Gas Times 2: 408 (June 1935)
# 593. Ibid.: Iron Steel Inst J 113: 229 (1926)
# 594. Ibid.: Combustion 3: 34 (Apr 1932); ibid., 12: 44, 125, 264 (Jan, Feb, Apr 1925)
# 597. Ibid.: Steam Engr 4: 465 (Aug 1935); ibid., 6: 279 (Apr 1937); ibid., 7: 319, 332 (1938)
# 598. Ibid.:  Combustion 2: 41 (Dec 1930), ibid., 1: 43 (Dec 1929)
# 601. Ibid.: Iron Coal Trade Rev 139: 575 (Oct 1929); ibid., 112: 348 (1926); ibid., 122: 137 (Jan 1931)
# 605. Ibid.: Engg 121: 564 (Apr 1926); ibid., 124: 36 (1927); 113: 125 (Feb 1922); ibid., 113: 125 (Feb 1922); ibid., 124: 36 (1927)
# 608. Ibid.: Soc. Chem Ind J 56: 895 (Oct 1937); ibid., 43: 2 (Jan 1924); Ibid., 48: 619 (June 1929); ibid., 29: 734 (July 1937)
# 657. Christie, A.: Power Plant Eng 30: 688 (June 1926)
# 660. Ibid.: Colliery Eng 5: 71 (Feb 1928)
# 661. Ibid.: Mining Rev 30: 15 (Feb 1929)
# 662. Ibid.: Chem Age (London) 35: 187 (Aug 1936)
# 665. Coffin, F.: Gas Age 48: 54 (July 1921)
# 667. Coles, et al: Eng 123: 391 (Apr 1927)
# 677. Davidson, T.: Gas J 153: 37 (1921); ibid., 158: 447 (May 1922)
# 678. Davies, W.: Chem Met Engg
# 681. Davis, J.: Coal Rev 3: 17 (Nov 1921)
# 682. Ibid.: US Bur Mines R.I. # 2292 (1921)
# 687. Ibid.: USBM R.I. # 2312 (1922)
# 688. Ibid.: Ind Eng Chem 20: 612 (June 1928)
# 689. Davis, J. & Karrick .: Amer Gas Assn Proc, . 670 (1925)
# 692. Davis, J.: Carnegie Inst & USBM Coop Bull # 8 (1923)
# 699. Demorest, D.: Chem Met Engg 34: 616 (Oct 1927)
# 700. Ibid.: Fuels & Furn 9: 1359 (Dec 1931)
# 701. Detken, F.: Engg Progress 17: 229 (Oct 1936)
# 704. Douglas, F.: Ind Eng Chem 28: 219 (Feb 1936)
# 705. Duffy, J.: Gas World 98: 12 (Jan 1933)
# 707. Dummett, G.: Inst Mining Eng Memo # 12 (Sept 1933)
# 709. Ibid.: Engg 49: 50 (Jan 1930)
# 710. Ibid.: Gas World 94, Coal Suppl, p. 19 (May 1931)
# 711. Evans, E.: Chem Ind 37: 212 (July 1918)
# 713. Evetts, G.: Gas J 160: 427 (Nov 1922)
# 719. Fieldner, A.: Amer Gas J 124: 50, 179, 426, 499, 540 (1925); ibid., 125: 119  (1926)
# 726. Ibid.: Fuel 5: 203, 265 (May June 1926); ibid., 7: 492 (1928)
# 727. Ibid.: Mech Engg 48: 1217 (Nov 1926)
# 729. Ibid.: Mining & Met. 20: 50 (Jan 1939)
# 733. Ibid.: USBM Mineral Yearbk 1932-37
# 735. Ibid.: USBM Monogr 5 (1934)
# 737. Ibid.: Ind Eng Chem 22: 1113 (1930)
# 739. Fieldner, et al: USBM T.P. # 542 (1932); ibid., # 570 (1936); ibid., # 572 (1936); ibid., # 524 (1932); ; ibid., # 525 (1932); ibid., # 571 (1936); ibid., # 548 (1933); ibid., # 519 (1932); ibid., # 584 (1938); ibid., # 511 (1932); ibid., # 411 (1937); *** ibid., # 543 (1932).
# 753. Findlayson, T.: Gas J 205: 148 (Jan 1934)
# 754. Fischer, et al: Fuel 7: 148 (May 1933)
# 758. Fisher, A.: Gas J 217: 100 (Jan 1937)
# 759. Foxwell, G.: Colliery Eng 10: 328 (Oct 1933); ibid., 10: 311 (Sept 1933)
# 760. Ibid.: Gas World 101: 322 (1934); ibid., 97: 201 (Sept 1932); ibid., 98: 199 (Mar 1933)
# 762. Ibid.: Gas Eng 51: 457 (1934)
# 773. Garland, C.: Power 60: 490 (Sept 1924)
# 781. Girouard, P.: Chem News 123: 280 (1921)
# 785. Gray, T.: Grt Brit Fuel Res Bd T.P. # 1 (1921); ibid., T.P. # 7 (1923)
# 795. Haslam, G. Fuel 7: 292 (July 1928)
# 796. Ibid.: Gas Eng 11: 640 (Nov 1930)
# 802. Holmes, C.: Gas World 88: 16 (March 1928)
# 804. Hood, O. & Odell, W.: USBM Bull # 255 (1926)
# 806. Humphrys, N.: Gas J. 178: 370 (May 1927)
# 807. Huttl, J.: Engg Mining J 128: 586 (1929)
# 821. Kershaw, J.: Engr 146: 651 (1928); ibid., 148: 364, 380 (Oct 1929)
# 823. Ibid.: Combustion 19: 308 (Dec 1928)
# 824. King, J.: Petr Times 30: 427, 451 (1933)
# 826. Ibid.: Fuel 9: 213 (June 1930)
# 831. Kurodo, T.: Fuel 11: 56 (Feb 1932)
# 833. Lander, C.: Coll. Guard. 140: 2402 (June 1930)
# 835. Ibid.: Gas World 92: 36 (Jan 1930)
# 837. Ibid.: Enginr. 133: 382 (Apr 1922); ibid., 149: 485 (May 1930)
# 840. Ibid.: Fuel Econ Rev 5: 10 (1926); 7: 16, 18 (1927); ibid., 8: 13 (1929)
# 849. Ibid.: Gas World 89: 320 (Oct 1928)
# 854. LeClerc: Coll. Guard. 153: 1 (July 1936)
# 855. LeGrand, C.: Fuel 17: 4, 41, 65, 96 (Jan-Apr 1938)
# 856. Lessing, R.: Fuel 124: 137 (Aug 1922)
# 859. Loebinger, K.: Amer Gas J 131: 35 (Dec 1929)
# 860. Ibid.: 53: 447 (Oct 1927)
# 862. Ibid.: Coll Guard. 131: 1023, 1162 (19260; ibid., 138: 1021 (March 1929); ibid., 141: 301 (July 1930); ibid., 155: 430, 468 (Sept 1937); ibid., 139: 2069 (Nov 1929); ibid., 147: 356 (Aug 1938); ibid., 153: 377 (Aug 1936); ibid., 132: 348 (Aug 1926).
# 868. Ibid.: Eng. 116: 168 (Aug 1923); ibid., 122: 699 (Dec 3, 1926); ibid., 123: 185 (Feb 1927); ibid., 133: 65 (Jan 1932)
# 909. Lymnan, A.: Iron Coal Trade Rev 112: 332 (1926)
# 910. McBride, R.: Chem Met Eng 35: 468 (Aug 1928)
# 912. Macdougall, D.: Fuel Econ. 7: 436 (July 1932)
# 913. McIntire, C.: Chem Age (NY) 31: 449 (Oct  1923)
# 916. Maclaurin, R.: Chem Ind 38: 6920 (June 1917)
# 917. Manning, A.: Inst Petr Tech J 21: 459 (June 1935)
# 918. Mathews, M.: Inst Petr Tech J 18: 415 (1932)
# 919. Monnett, O.: Chem Met Eng 23: 1246 (1920)
# 921. Mouilpied, A.: Electrician 102: 3 (Jan 4 1929)
# 923. Ibid.: Oil & Gas J 37: 178 (Dec 1938)
# 924. Muller, F.: Mining J (Lond) 194: 721, 728 (July-Aug 1928)
# 925. Mulvihill, B: Mining Rev 30: 99: 76 (July 1933)
# 929. Murray, W.: Iron Coal Trade Rev 126: 199 (Feb 1933)
# 931. Nielsen, H.: Iron Coal Trade Rev 113: 34 (1926)
# 933. Ode, W.: USBM R.I. # 3342 (1937)
# 934. Ibid.: Amer Gas Assn Proc, p. 879 (1925)
# 936. Oetken, F.: Eng Progress 17: 229 (1936)
# 939. Ibid.: Nature 141: 1110 (June 1938)
# 940. Ibid.: Coll Guard. 157: 886 (Nov 1938); ibid., 156: 307, 346 (Feb 1938)
# 943. Omori, K.: Fuel 3: 360 (Oct 1924)
# 946. Orrok, G.: Mech Engg 49: 1055 (Oct 1927)
# 947. Ibid.: Electr. World 86: 620 (1925)
# 951. Parker, O.: Coll Guard. 132: 668 (Sept 1926)
# 953. Parr, S.: Ind Eng Chem 5: 640 (June 1926); ibid., 18: 1015 (Oct 1926)
# 963. Parr & Layng, T.: J Ind Eng Chem 13: 14 (Jan 1921)
# 968. Perrott, G.: USBM R.I. # 2341 (1922)
# 972. Pitt, G: Coll Guard 2: 134 (March 1925)
# 979. Porter, H.: Ind Eng Chem 24: 1363 (Dec 1932)
# 981. Ibid.: Iron Coal Trade Rev 104: 576 (1922)
# 983. Ibid.: Oil & Gas J 36: 14 (1938)
# 984. Ibid.: Eng 142: 522 (Nov 1936)
# 985. Ibid.: Chem Age (Lond) 16: 62 (Jan 1927)
# 989. Puening, F.: Gas World 98: 7, 199 (1933)
# 990. Rambushi, N.: Fuel 5: 12 (Jan 1926)
# 991. Ibid.: Chem Met Eng 26: 1086 (June 1922)
# 997. Reynolds, D.: Ind Eng Chem 26: 732 (July 1934)
# 998. Rhead, F.: Gas World 98: 113 (Feb 1933)
# 999. Riley, H.: Gas World 107: 118 (1937)
# 1000. Roberts, J.: Coll Guard 122: 445, 1067 (1927)
# 1003. Ibid.: Iron Coal Trade Rev 103: 193 (Aug 1921); ibid., 104: 576 (1922)
# 1011. Ibid.: Fuel Econ 2: 450 (May 1927); ibid., 9: 405, 450 (1934)
# 1020. Ibid.: Inst Fuel J 7: 106 (Dec 1933)
# 1021. Robertson, W.: Gas World 82: 15 (Feb 1925)
# 1023. Rogers, J.: World Power 12: 493 (Nov 1929)
# 1025. Roser, I.: Gas Engg 23: 5 (Jan 1921)
# 1026. Rosin, P.: Coll Guard. 139: 2069, 3597 (Nov Dec 1929)
# 1027. Ibid.: Inst Fuel J 3: 189 (Jan 1930)
# 1032. Runge,W.: Coal 1: 327 (May 1926)
# 1033. Ibid.: Mech Engg 49: 875 (Aug 1927)
# 1035. Sander, A.: Engg Progr 11: 246 (Sept 1930)
# 1036. Savage, H.: Engrs & Engg 45: 183 (Aug 1928)
# 1037. Ibid.: Chem Met Engg 19: 579 (Oct 1918)
# 1039. Schmidt, L.: Fuel 16: 39 (Feb 1937); ibid., 11: 244 (July 1932)
# 1046. Scott, E.: Eng 145: 96, 178 (Jan Feb 1938)
# 1050. Shimimura, A.: Fuel Soc Jap J 14: 25 (1935)
# 1051. Ibid.: Chem Age (Lond) 55: 268 (Mar 1925)
# 1053. Sinnatt, F.: Gas J (Lond) 212: 711 (Dec 1935)
# 1056. Ibid.: Fuel 7: 305, 364 (Jul Aug 1928)
# 1058. Slater, L.: Fuel 6: 82 (Feb 1927)
# 1059. Smith, E.: Coll Guard 139: 1292 (Oct 1929)
# 1060. Ibid.: Gas J 176: 433 (Nov 1`926)
# 1062. Smythe, E.: Soc Chem Ind J 50: 588 (July 1931)
# 1063. Ibid., Power Engr 24: 277 (July 1929)
# 1064. Ibid.: Coll Guard 143: 1705 (Nov 1931)
# 1065. Ibid.: Inst Fuel J 3: 190 (Jan 1930)
# 1067. Ibid.: Gas J 223: 453 (Aug 1938)
# 1070. Ibid.: Gas Age Rec 60: 605 (Oct 1927); 60: 393 (Sept 1927)
# 1073. Spiers, H.: Ind Chem 2: 315 (July 1926)
# 1076. Stansfield, E: J Ind Eng Chem 13: 17 (Jan 1921)
# 1078. Ibid.: Chem Met Eng 33: 748 (Dec 1926)
# 1079. Strevens, J.: Gas & Oil 31: 225 (1936)
# 1081. Ibid.: Fuel Econ 5: 437 (1930)
# 1082. Ibid.: Nature 141: 812 (May 1938)
# 1086. Stuart, M.: Gas World 88: 633 (June 1928)
# 1091. Taylor, F.: Amer Gas J 117: 561 (Nov 1922); ibid., 118: 561 (June 1923)
# 1093. Ibid.: Engineer 159: 184 (Feb 1935); ibid., 161: 686 (June 1936)
# 1095. Thau, A.: Gas Times 10: 25 (Jan 1937)
# 1097. Ibid.: Gas World 110: 172 (Feb 1939)
# 1100. Ibid.: Fuel Econ 1: 367 (1926)
# 1103. Thomas, H.: Soc Chem Ind J 47: 77-T (Mar 1928)
# 1110. Chem Met Eng 29: 142, 233 (Jul Aug 1923)
# 1114. Uchida, S.: Fuel 7: 179 (Apr 1928)
# 1116. Ibid.: Engineer 148: 350 (Oct 1929)
# 1118. Walker, H.: Gas Age Rec 70: 27 (1932)
# 1119. Wallace, G.: Combustion 19: 87 (Aug 1928)
# 1121. Ward, J.: Gas Age Rec 59: 338 (Mar 1927)
# 1123. Weyman, G.: Gas J 173: 601, 677, 746 (Mar 1926) ***
# 1124. Wheeler, R.: Coll. Guard. 132: 405 (Aug 1926)
# 1126. Whittaker, J.: Iron Coal Trade Rev 118: 325 (Mar 1929)
# 1128. Wilson, R.: Coll Guard 136: 1538 (Apr 1928); ibid., Gas J 182: 245 (Apr 1928)
# 1129. Winmill, T.: Soc Chem Ind J 36: 912 (Aug 1917)
# 1130. Iron Coal Trade Rev 122: 685 (May 1931)
# 1131.  Wright, H.: Gas J 195: 32 (July 1931)
# 1132. Yancey, H.: USBM T.P. # 512 (1932)

Processes ~

# 1133. Ab-Der-Halden
Ab-Der-Halden, C.: Int Conf Bitum Coal Proc 1: 352 (1931)

AVG: See Kollergas
Addy: See Carlton
Allkog: See Fellner-Ziegler
American Lurgi Corp: See Lurgi

# 1134. Babcock
Gas J 184: 469 (1928); ibid., 190: 297 (May 1930)
Chem Age (Lond) 22: 556 (June 1930)
Brownlie, D.: Combustion 3: 34 (Apr 1932); ibid., 1: 43 (Dec 1929)
Ibid.: Soc Chem Ind J 49: 92 (Jan 1930)
Ibid.: Eng 126:787 (Dec 1928); ibid., 131: 386, 459 (Mar 1931)
Ibid.: Ind Chem 4: 473 (Nov 1928)
Matthews, F.: Coll Eng 7: 147 (Apr 1930); ibid., 137: 1231 (Sep 1928)
Sloan, R.: Iron & Coal Trade Rev 117: 727 (Nov 1928)

# 1135. Berg
Brownlie, D.: Soc Chem Ind J 56: 895 (Oct 1937)
Ibid.: Ind Eng Chem 29: 734 (Jul 1937)

# 1136. Bituminoil
Vandegrift, J.: Iron Coal Trade Rev 121: 290 (Aug 1930)
US Patent # 1,976,816, App. for Distilling Carbonaceous Material (James Vandegrift & Carl Postel, Oct 16, 1934); USP # 1,995,873, Retort (Vandegrift & Postel, March 26, 1935); USP # 2,041,882, Retort (Vandegrift, May 26, 1936); USP # 1,916,900, Method of Low Temperature Distillation (Vandegrift & Postel, July 4, 1933); USP # 2,041,883, App. for Producing Fuel (Vandegrift & Postel, May 26, 1936); USP # 2,066,082, App. for Producing Fuel (Vandegrift & Postel, Dec. 29, 1936); USP # 2,066,083, Fuel & Method of Producing Said Fuel (Vandegrift & Postel, Dec. 29, 1936).

# 1137. Bluemner
Fuel 15: 271 (Oct 1936)
Brownlie, D.: Ind Eng Chem 28: 629 (June 1936); ibid., 28: 839 (1936)
Ibid.: Iron Coal trade Rev 133: 415 (1936)

# 1138. Bonnevie
Fuel 7: 134 (Mar 1928)

# 1139. Bostaph
Unpublished data

# 1140. Bowing
Mines & Mining 20: 47 (Aug 1899)

# 1141. Brennstoff-Technik
Brownlie, D.: Fuel Econ 12: 417, 506 (Sep Nov 1937)
Ibid.: Ind Eng Chem 29: 734 (July 1937)

British Carbonized Fuels, Ltd; See Hird
British Coal Distillation Ltd: See Suncole

# 1142. Burney
McKay, R.: Unpublished data

# 1143. Bussey
Brownlie, D.: Gas Age Rec 64: 141 (Aug 1929)
Ibid.: Soc Cem Ind J 48: 934 (Aep 1929)
Ibid.: Coll Guard. 138: 1432 (Apr 1929); ibid., 139: 328 (July 1929)
Cronshaw, H.: Eng 127: 409 (Mar 1929)
Ibid.: Chem Age (Lond) 25: 97 (July 1931)
Ibid.: Amer Gas J 132: 37 (May 1930)
Ibid.: Eng 133: 184 (Feb 1932)

CRS: See Rexco
CTG: See Plassman

# 1144. Cannock
Brownlie, D.: Ind Eng Chem 28: 29 (June 1936)
Cadman,, W.: Fuel Econ 10: 571 (Nov 1934); ibid., 12: 421 (Sep 1937)
Ibid.: Eng 144: 497 (Oct 1937)
Ibid.: Coll Guard 153: 47 (Jul 1936)
Morris, G.: Fuel Econ 11: 386 (1936)
Ibid.: Coll Guard 151: 700 (1935)

# 1145. Carbocite: See Wisner

# 1146. Carbocoal (See also McIntire)
Curtis, H.: J Ind Eng Chem 13: 23 (Jan 1921)
Ibid.: Chem Met Eng 23: 499 (Sep 1920); ibid., 28: 11 (1923); ibid., 28: 118 (Jan 1923); ibid., 28: 60, 171 (Jan 1923)
Fieldner, A.: Coal Age 31: 124 (Jan 1927)
Ibid.: Coll Guard 131: 1023, 1162 (1926)
Porter, H.: Frnaklin Inst J 199: 381 (Mar 1925)

# 1147. Carbolux
Fuel 12: 364 (Nov 1933)

#1148. Carbonol
Brownlie, D.: Ind Eng Chem 28: 629, 839 (1936)

Carburite: See Delkeskamp
Carlbrite: See Carlton

# 1149. Carlton
Brownlie, D: Ind Eng C hem 19: 39 (Jan 1927)
Ibid.: Gas Age Rec 59: 293 (Feb 1927)
Standley, W.: Instn Engineers (India) 6: 146 (July 1926)
Tupholme, C.: Chem Met Eng 30: 471 (Mar 1924)
USP # 1,980,245, Retort for LT Distillation (Addy, et al, Nov 13, 1934).

Catalysts, Ltd: See Gifford

[ Missing pages 810-811 ]

# 115-. Coalene
USP # 1,710,070, Still (Elmer Records, April 23, 1929); USP # 1,843,174, Coal Distillation App. (Records, Feb 2, 1932); USP # 1,884,017, Process of Distillation of Coal (J. Louttit & Records, Oct 25, 1932).

# 115- Coalite
USP # 1,687,989, Retort (Ch. Parker, Oct 16, 1928); USP # 1,687,990, Distillation of Coal (Parker, Oct 16, 1928); USP # 1,687,991, Distillation of Coal (Parker, Oct 16, 1928); USP # 1,689,152, App. for Distillation of Coal (Parker, Oct 12, 1928); USP # 1,754,693, Retort (Parker, April 15, 1930); USP # 1,827,800, Closure Mechanism for Retort Doors (Parker, Oct 20, 1931); USP # 1,860,591, Retort (Parker, May 31, 1932); USP # 2.014,583, App. for Distillation of Coal (Parker, Sept 17, 1935); USP # 1,989,459, Retort (Parker, Jan 29, 1935).

# 1155. Crozier
Coll Guard. 131: 348 (1926)

# 1156. Davidson
Davidson, T.: Ind Chem 7: 403 (Oct 1931)
Ibid.: Coll Guard 143: 783 (1931)
USP # 1,831,704, Rotary Retort for Treatment of Oil Shale (Th. Davidson, Nov 10, 1931).

# 1157. Davies
Tupholme, C.: Chem Met Eng 30: 861 (June 1924)

# 1158. Delkeskamp
Coll. Guard 131: 1023, 1162 (1926)
Brownlie, D.: Ind Eng Chem 29: 734 (Jul 1937)

# 1159. Derby-Horner
USP # 1,948,515, Method of Carbonizing (Ira Derby & H. Horner, Feb 27, 1934); USP # 2,029,759, App. for Treatment of Carb. Material (Derby & Horner, Feb 4, 1936); USP # 2,029,760, App. for Treatment (Derby & Horner, Feb 4, 1936); USP # 2,029,761, Method of Forming Charges (Derby & Horner, Feb 4, 1936); USP # 2,029,762, Method of Treating Carb. Material (Derby & Horner, Feb 4, 1936); USP # 2,029,763, App. for Treating Carb. Material (Derby & Horner, Feb 4, 1936).

# 1160. Dobbelstein
Coll Guard 131: 1023, 1162 (1926)
Thau, A.: Chem Met Eng 33: 227 (1926)
USP # 1,690,444, App. for Drying or Smoldering Loose Material (Otto Dobbelstein, Nov 6, 1928); USP # 1,718,542, App. for Drying &c (Dobbelstein, June 25, 1929); USP # 1,718,543, App. for Drying &c (Dobbelstein, June 25, 1929); USP # 1,718,544, App. for Drying &c (Dobbelstein, June 25, 1929).

# 1161. Dual Gas
Mining Rev 30: 26 (Sept 1928)

# 1162. Dvorkovitz
Blackall, A.: Combustion 18: 180 (Mar 1928)
Brownlie, D.: Gas Age Rec 62: 354 (Sep 1928)
Ibid.: Ind Eng Chem 19: 39 (Jan 1927)
Ibid.: Eng 125: 72 (Jan 1928)
Ibid., Gas J 181: 145 (Jan 1928)
Ibid.: Gas Engr 44: 16 (Jan 1928)
Ibid.: Gas & Oil 24: 171 (June 1929)
USP # 1,706,825, Retort (Paul Dvorkovitz, March 26, 1929)

# 1163. Eesti Patendi
Roberts, J,: Coll Eng 7: 373 (Oct 1930)

# 1164. Fellner-Ziegler
Brownlie, D.: Gas Engr 43: 317 (Dec 1927)
Hood, O.: USBM Bull 255 (1926)
Schutz,F.: Iron Coal Trade Rev 111: 140, 182, 212 (Jul Aug 1925)
Thau, A.: 106: 486 (1923)
Ibid.: Coal Age 20: 873 (Dec 1921)

[# 1164a Fenton
USP # 1,484,256, Intermittent System for Treatment of Coal (James Fenton, Feb 19, 1924); USP # 1,484,257, Continuous System for Treatment of Coal (Fenton, Feb 19, 1924); USP # 1,484,258, Proc. for Treatment of Coal (Fenton, Feb 19, 1924).]

# 1165. Freeman
Brownlie, D.: Gas Age Rec 60: 143 (Jul 1927)
Ibid.: Coll Guard 133: 264 (Feb 1927)
Ibid.: Eng 123: 230 (Feb 1927)
Tupholme, C.: Chem Met Eng 30: 54 (1924)

#1166. Fuel Research Board
Coll Guard 139: 1191, 1288 (Sep Oct 1929)
Chem Age (Lond) 28: 178 (Feb 1933)
Amer Gas J 138: 37 (Aug 1933)
Eng 122: 166 (Aug 1926)
Gas J 163: 581 (1923)
Gas World 79: 139 (1923)
Lander, C.: Chem Met Eng 34: 147 (Mar 1927)
Eng 116: 212 (Aug 1923)
FRB Tech Ppr 35: (1933); ibid., 15 (1926; ibid., 7 (1923)

# 1167. Fusion
Brownlie, D.: Gas Age 59: 591
Ibid.: Ind Eng Chem 19: 39 (Jan 1927)
Dundas, F.: Fuel 7: 318 (Jul 1928
Hutchins, S.: Coll Guard 129: 331 (1925)
Tupholme, C.: Chem Met Eng 29: 752 (Oct 1923); ibid., 34: 617 (Oct 1927)

Gas & Coke Co: See Hird

# 1168. Geissen
Fieldner, A.: USBM T.P. # 396 (1926)
Hood, O.: USBM Bull # 255 (1926)
Kerschbaum, F.: Electrician 96: 644, 669 (Jun 1926)
Mueller, F.: Int Conf Bit Coal Proc p 766 (1926)

# 1169. Gibbons/Cellan-Jones
Iron Coal Trade Rev 154: 173, 446 (Jan 1937)
Coll Guard 154: 195 (Jan 1937)
Schwartz, P.: Gas World 105: 139 (1936)
USP # 2,103,620, Coke Oven (G. Cellan-Jones, Dec 28, 1937).

# 1170. Gifford
Fuel Econ 12: 464 (Oct 1937)
Coll Guard 155: 373 (Aug 1937)
Brownlie, D.: Soc Chem Ind J 56: 895, 989 (Oct 1937)

Glover-West: See Fuel Research Board

# 1171. Greene-Laucks
Fieldner, A,: Coal Age 31: 124 (Jan 1927); ibid., 15: 810 (May 1919)
Ibid.: USBM T.P. # 396 (1926)
Laucks, J.: Ind Eng Chem 19: 8 (Jan 1927)
Porter, H.: Frankling Inst J 199: 381 (Mar 1935)
USP # 1,713,840, Method & App. for Carbonizing Coal (Irving Laucks, May 21, 1929); USP # 1,723,932, App. for Carbonizing Coal (Fr. Greene, Aug 6, 1929); USP # 1,730,569, App. for Extracting Values (Greene, Oct 8, 1929); USP # 1,854,300, Method & App. for Carbonizing Coal (April 19, 1932); USP # 1,890,661, App. for Carbonizing Coal (Greene, Dec 13, 1932).

# 1172. Greenstreet
Brownlie, D.: Ind Eng Chem 28: 629 (June 1936)
DeRamel: Petr Times 29: 412 (Apr 1938)

# 1173. Haken
Brownlie, D.: Ind Eng Chem 29: 734 (July 1937)
Ibid.: Fuel Econ 13: 506 (Nov 1937)

# 1174. Hanl
Brownlie, D.: Combustion 1: 43 (Dec 1929)

# 1175. Hardy-Hector
Brownlie, D.: Petr. Times 27: 665 (June 1932)

# 1176. Hayes
Fuels & Furn 7: 1945 (Dec 1929)
McQuade, J.: ASME Trans52: 153 (May aug 1930)
US P # 1,595,933, Reverse Gearing (Ch. Hayes, Aug 10, 1926); USP # 1,595,934, Proc. for Carbonization (Hayes, Oct 10, 1926); USP # 1,662,575, Conveyer (Hayes, March 13, 1928); USP # 1,810,828, Method of Carbonizing Coal (Hayes, June 16, 1931); USP # 1,881,826, App. for Carbonization (J. McQuade, Oct 11, 1932); USP # 1,884,379, Carbonization Device (Fr. Tenney, Oct 25, 1932).

# 1177. Hereng
Brownlie, D.: Combustion 3: 34 (Apr 1932); ibd., 1: 43 (Dec 1929)

# 1178. Hinselmann
Brownlie, D.: Fuel Econ 12: 417, 506 (Sep Nov 1937)

# 1179. Hird
Brownlie, D.: Ind Eng Chem 19: 39 (Jan 1927)
Hird, H.: Fuel 7: 319 (July 1928)
Ibid., Coll Guard 151: 722 (1935); ibid., 139: 1191, 1288 (Sep Oct 1929)
Ibid.: Coll Eng 4: 147 (Apr 1927); ibid., 4: 147 (Apr 1927)
Ibid.: Petr Times 15: 20 (Jan 1926)
USP # 1,530,986, App. for Carbonization (Harold Hird, March 24, 1925).]

# 1180. Holcobami
Brownlie, D.: Gas Age Rec 59: 889 (June 1927)
Ibid.: Coll Guard 143: 790, 1666 (Sep Nov 1931)
USP # 1,636,975, Retort Oven for LTC (P. Zuyderhoudt, July 26, 1927); USP # 1,968,896, Retort Oven (J. Mage, Aug 7, 1934); USP # 1,975,621, Retort Oven for LTC (J. Schafer, Oct 2, 1934).]

# 1181. I
Inst Petr Tech (1936) p. 186

# 1182. Honigmann-Bartling
Brownlie, D.: Gas Age Rec 63: 69 (1929)

# 1183 Hood-Odell
Brownlie, D.: Gas Engr 43: 164 (July 1927)
Fieldner, A.: USBM T.P. # 396 (1926)
USP # 1,926,058, Process of Purifying Gas (Sept 12, 1933).

# 1184. Illingworth
Brownlie, D.: Ind Eng Chem 19: 39 (Jan 1927)
Fieldner, A.: USBM T.P. # 396 (1926)
Illingworth, S.: Coll Guard 144: 629 (Apr 1932)
Ibid.: Fuel 7: 320 (July 1928)
Ibid.: Gas World 82: 602 (1925)
Ibid.: Iron Coal Trade Rev 104: 575 (1922); ibid., 158: 122 (Jan 1929)
Ibid.: Coll Eng 4: 357 (Sep 1927)
Ibid.: Fuel 9: 1 (Jan 1930)
Ibid.: Engr 148: 150 (Aug 1929)
Ibid.: Coll Guard 144: 629 (Apr 1932); ibid., 87: 919
Ibid.: Inst Petr Tech (1936), p. 272
Muir, D.: Gas J 184: 30 (Oct 1928)
USP Re. # 17,572 (USP # 1,645,861), App. for Manufacture of Carbonized Fuel (S. Illingworth, Jan 28, 1930); USP # 1,716,726, Agitating System (Illingworth, June 11, 1929); USP # 1,716,727, App. for Cooling of Coke (Illingworth, June 11, 1929); USP # 1,800,633, App. for Manufacture of Carbonized Fuel (Illingworth, April 14, 1931); USP # 1,861,345, App. for Manufacture of Carbonized Fuel (Illingworth, May 31, 1932); USP # 1,895,798, App. for Feeding Coal (Illingworth, Jan 31, 1933); USP # 1,923,209, Plant for Carbonization of Coal (Illingworth, Aug 22, 1933).

[ # 1184a. Jenson
 USP # 1,734,970, Proc. & App (James Benson, Nov 12, 1929) ]

# 1185. KSG
Andrew, H.: Gas Age Rec 63: 477 (Apr 1929)
Brownlie, D.: Soc Chem Ind J 48: 569 (June 1929)
Cautieny, G.: Eng Progr 6: 349 (Nov 1925)
Hall, R.: Coal Age 34: 229 (Apr 1929)
Hazeldon, J.: Fuel 7: 155 (Apr 1928); ibid., 6: 289 (1927); 8: 255 (June 1929)
Ibid.: Iron Coal Trade Rev 119: 120 (July 1929)
Ibid.: Coll Guard 139: 1191 , 1288 (Sep Oct 1929)
Ibid.: Gas J 184: 29 (Oct 1928)
Ibid.: Petr Times 20: 547 (Sep 1928)
Ibid.: Amer Gas J  130: 26 (Apr 1929)
Ibid.: Ind Eng Chem 5: 387 (Sep 1929)
Ibid.: Chem Age (Lond) 22: 134 (Feb 1930)
McBride, R.: Chem Met Eng 36: 288 (May 1929)
Montgomery, R.: Power 69: 593 (Apr 1929)
Mueller, F.: Combustion 16: 155 (May 1927)
Runge, W.: ASME Trans 50: 17 (May Aug 1928)
Soule, R.: Can Chem & Met 13: 45 (Feb 1929)
Ibid.: Combustion 20: 132 (Mar 1929)
Ibid.: Gas Age Rec 60: 605 (Oct 1927)

# 1186. Karrick
Anderson, B., et al.: Thesis BS, Univ Utah (1935)
Carter, G.: Thesis MS, Univ Utah (1934)
Carter, G.: Utah Acad Sci Proc 11: 117 (1934)
Jacobsen, S. & Carter: Thesis BS, Univ Utah (1933)
Ibid.: Ind Eng Chem. 27: 1278 (Nov 1935)
Ibid.: Mech Eng 57: 305 (May 1935)
Ibid.: Coal Age 41: 148 (Apr 1936)
Ibid.: Mining Rev 36: 11 (July 1934)
Ibid.: Mining Rev 34: 8 (Feb 1932)
Larsen, W. & Stutz, C.: Thesis BS , Univ Utah (1932)
Mellor, M. & Woodhead, R.: Thesis BS, Univ Utah (1936)
Ibid.: Minig Rev 34: 10 (June 1932)
USP # 1,832,219, Proc. & App. for Superheating Steam (Lewis Karrick, Nov 17, 1931); USP # 1,894,691, Destructive Distillation (Karrick, Jan 17, 1933); USP # 1,899,154, Valve (Karrick, Feb 28, 1933); USP # 1,901,169, Distillation (Karrick, March 14, 1933); US # 1,906,755, Method of LTC (Karrick, May 2, 1933); USP # 1,913,395, Underground Gasification (Karrick, June 13, 1933); USP # 1,923,213, Proc. & App. for Carbonizing Coal (Karrick, Aug 22, 1933); USP # 1,938,596, Retort (Karrick, Dec 12, 1933); USP # 1,942,650, App. for Coking Bituminous Liquids (Karrick, Jan 9, 1934); USP # 1,945,530, Destructive Distillation (Karrick, Feb 6, 1934); USP # 1,950,558, Proc. for Production of Gas &c. (Karrick, March 13, 1934); USP # 1,958,918, Proc. of Destructive Distillation (Karrick, May 15, 1934); USP # 2,011,054, Proc. of Destructive Distillation (Karrick, Aug 13, 1935); Re. # 20,392 (USP # 2,011,054), Proc. of Destructive Distillation (Karrick, June 1, 1937).

# 1187. Kemp
Finn, C.: Coal Carb. 2: 137 (1936)
Ibid.: Coll Guard. 154: 633 (Apr 1937)
Schwartz, P.: Gas World 105: 139 (1936)

# 1188. Knowles
Coal Combustion 1: 123 (1935)
Brownlie, D.: ind Eng Chem 28: 629 (June 1936)

# 1189. Kollergas/AVG
Brownlie, D.: Gas Age Rec 64: 755 (Nov 1929)
Ibid.: Gas Engr 43: 194 (Aug 1927)
Ibid.: Ind Eng Chem 29: 734  (July 1937)

# 1190. Kopperskohle
Koppers, H.: Fuel Econ.: 9: 275 (Apr 1934)

# 1191. Krupp-Lurgi
Brownlie, D.: Fuel Econ 12: 417, 506 (Sep Nov 1937)
Ibid.: Ind Eng Chem 29: 734 (July 1937)

L & N: See Suncole

# 1192. Lamplough
Brownlie, D.: Mech Eng 59: 772 (Oct 1937)

# 1193. Lead-Bath
Morgan, J.S.: Iron Coal Trade Rev 106: 530 (Apr 1923);
Ibid.: Coll Guard 125: 885 (Apr 1923)
Strong, R.: Canada Mines Bur Publ # 689 (1928); ibid., # 696 (1929); ibid., # 671 (1927)

# 1194. Lecocq
Coal Carb 4: 176 (Nov 1938)
Schawrtz, P.: Gas World 105: 139 (1936)

LeHigh Brigquetting Co: See Lurgi

# 1195. Lewis
Brownlie, D.: Ind Eng Chem 28: 629 (June 1936)

#1196. Lloyd
Petr Tech  (1936), p. 275

Low Temperature Carbonization, Ltd.: See Coalite

# 1197. Lurgi
Coal Age 42: 69 (1937)
Mining Rev 29: 7 (Mar 1928)
Mining Rec 30: 13 (Mar 1928)
Fieldner, A.: USBM T.P. # 396 (1926)
Ibid.: Fuels & Furn 7: 1945 (Dec 1929)
Ibid.: Mining Rev 30: 15 (Nov 1928)

# 1198. McEwen-Runge
Brown, R.: Gas J 179: 218 (July 1927)
Brownlie, D.: Gas Engr 43: 85 (Apr 1927)
Ibid.: Power Plant Eng 30: 688 (June 1926)
Ditto, M.: Fuels & Furn 3: 1331 (Dec 1925)
Fieldner, A.: Coal Age 31: 124 (Jan 1927)
Ibid.: USBM T.P. # 396 (1926)
Hall, R.: Coal Age 29: 112 (Jan 1926)
McEwen, S.: Coll Guard 133: 263 (Feb 1927); 139: 2068, 2179 (Nov Dec 1929)
Ibid.: Inbst Fuel J 3: 181 (Jan 1930)
Ibid.: Engr 140: 249 (Sept 1925)
Runge, W.: Int Conf Bit Coal Proc p 697 (1926)
Ibid.: Gas Age Rec 58: 765 (Nov 1926)
Soule, E.: Combustion 17: 227 (Oct 1927)
Ibid.: Power 66: 222 (Aug 1927)
USP Re. # 17,181 (USP # 1,481,140), Carbonization of Coal (Samuel McEwen, Jan 1, 1929); Re. # 17,182 (#1,481,140), Method of Carbonization (McEwen, Jan. 1, 1929).

# 1199. McIntire
Ditto, M.: Fuels & Furn 3: 1331 (Dec 1925)
Fieldner, A.: USBM T.P. # 396 (1926)
McIntire, C.: Int Conf Bit Coal Proc p 650 (1926)
Ibid.: Power Plant Eng 30: 579 (May 1926)
Ibd.: Ind Eng  Chem 19: 12 (Jan 1927)

# 1200. MacLaurin
Blackall, A.: Eng & Fin, 21: 84 (Aug 1929)
Brownlie, D.: Ind Eng Chem 19: 39 (Jan 1927)
Ibid.: Soc Chem Ind J 48: 619 (June 1929)
Ditto, M.: Fuels & Furn 3: 1331  (Dec 1925)
Fieldner, A.: USBM T.P. # 396 (1926)
Lander, C.: Gas World 91: 61 (July 1929)
Ibid.: Power Engr 20: 461 (Dec 1925)
MacLaurin, R.: Fuel 7: 323 (July 1928)
Ibid.: Iron Coal Trade Rev 102: 848 (Jun 1921); ibid., 104: 575 (1922)
Ibid.: Gas J 158: 325 (1922); ibid., 131: 37 (Sept 1929)
Ibid.: Coll Guard 151: 722 (1935); ibid., 138: 2299 (June 1929)
Ibid.: Fuel 11: 354 (Oct 1932)
Ibid.: Eng 118: 682 (Nov 1924)
Puening, F.: Chem Met Eng 26: 1086 (June 1922)
Scott, E.: Combustion 13: 166 (1925)
Ibid.: Eng 118: 491 (Oct 1924)
Sturrock, R.: Gas World 80: 52 (Jan 1924)
Tasker, C.: Electr Rev 105: 373 (Aug 1929)
Tupholme, C.: Chem Met Eng 29: 1138 (Dec 1923); ibid., 30: 397 (Mar 1924)

# 1201. Marshall-Easton
Brownlie, D.: Ind Eng Chem 19: 39 (Jan 1927)
Ditto, M.: Fuels & Furn 3: 1331 (Dec 1925)
Marshall, F.: Gas J 162: 667 (June 1923)

# 1202. Meguin
Coll Guard 131: 1023, 1162 (1926)

# 1203. Meiro
Brownlie, D.: Ind Eng Chem 28: 629 (June 1936)

Merz-McLellan: See Babcock

# 1204. Midland
Brownlie, D.: Ind Eng Chem 19: 39 (Jan 1927)

Mitford-Brocklebank: See Cannock

# 1205. Modified Mond (Power Gas)
Bosch, A.: Gas World 74: 273 (1921)
Puening, F.: Chem Met Eng 26: 1086 (June 1922)
Tupholme, C.: Chem Met Eng 30: 271 (Feb 1924)

# 1206. Moeller
Brownlie, D.: Steam Engr 6: 462 (Aug 1937)

# 1207. Mondello
Brownlie, D.:  Ind Eng Chem 28: 629 (June 1936)

# 1208. Moore
Gr Brit Labour Party: Labour’s Plan For Oil From Coal, p. 29 (1938)
# 1209. Morgan
Brownlie, D.: Steam Engr 7: 49 (Nov 1937)
Ibid.: Ind Eng Chem 29: 734 (July 1937)
Ibid.: Soc Chem Ind J 56: 895, 989 (Oct 1937)
Ibid.: Coll Guard 156: 1041 (June 1938)
Ibid.: Chem Age (Lond) 38: 462 (June 1938)
Ibid.: Engr 165: 648 (June 1938)
Morgan, J.: Fuel Econ 14: 302 (Sept 1938)
Ibid.: Eng 146: 113 (July 1938)
Ibid.: Coal Carb. 4: 106 (July 1938)

# 1210. Mosicki
Moritz, R.: Amer Gas J 119: 129 (Aug 1923)

NTU: See Rexco
Naco: See Cannock
National Carbonizing Co: See Rexco
National Coke & Oil Ltd: See Cannock

[ # 1210a. NFC
USP # 2,030,852, Proc. of Distilling Coal (G. Berry & A. Beardsley, Feb 18, 1936); USP # 2,131,702, Coal Processing (Berry, Sept 27, 1938) ]

# 1211. Otto
Brownlie, D.: Ind Eng Chem 29: 734 (July 1937)
Ibid.: Fuel Econ. 12: 417, 506 (Sep Nov 1937)

Packer: See Coalite

# 1211a.  Parker
USP # 1,822,541, Retort (R. Parker, Sept 8, 1931); USP # 1,922,321, Method of Extracting (Parker, Aug 15, 1933) ]

# 1212. Parr
Chapman, W.: Fuel 5: 355 (Aug 1926)
Fieldner, A.: Coal Age 31: 124 (Jan 1927)
Ibid.: USBM T.P. # 396 (1926)
Parr, S.: Ind Eng Chem 21: 164 (Feb 1929)
Ibid.: Int Conf Bit Coal Proc p. 54 (1928)
Powell, A.: Mech Eng 46: 389 (1924)
USP # 1,754,765, Coking Coal (S. Parr & T. Layng, April 15, 1930); USP # 1,827,483, App. for Coking Coal (Parr & Layng, Oct 13, 1931); USP # 1,874,344, (Parr & Layng, Aug 30, 1932); USP # 1,907,568, Proc. for Coking Coal (Parr & Layng, May 9, 1933); USP # 1,907,569, Proc. of Preparing Coal (Parr & Layng, May 9, 1933); USP # 1,909,421, Proc. For Coking Coal (Parr & Layng, May 16, 1933).

Patent Retorts Ltd: See Davidson

# 1213. Pehrson
Chapman, W.: Soc Chem Ind J 48: 189T (July 1929)

# 1214. Pieters
Eng 126: 363 (Sept 1928)

# 1215. Pintsch
Brownlie, D.: Combustion 3: 34 (Apr 1932)
Ibid.: Combustion 1: 43 (Dec 1929)
Brownlie, D.: Ind Eng Chem 29: 734 (July 1937)

# 1216. Piron-Caracristi
Brownlie, D.: Power Eng 18: 368 (Oct 1923)
Caracristi, V.: Power 57: 831 (May 1923)
Ibid.: Amer Gas J 119: 65, 76 (June 1923)
Ibid.: Franklin Inst J 202: 323 (Sept 1926)
Ibid.: Chem Age (NY) 31: 361 (1923)
Fieldner, A.: Coal Age 31: 124 (Jan 1927)
Ibid.: USBM T.P. # 396 (1926)
Lamie, R.: Coal Age 24: 171 (Aug 1923)
Piron, E.: Canad Mining J 47: 1148 (Dec 1926)
Ibid.: Int Conf Bit Coal  p. 729 (1926)
Porter, H.: Frankkin J Inst 199: 381 (Mar 1925)
USP # 1,664,483, App. for Absorbing Fluids from Gases (E. Piron, April 3, 1928); USP # 1,664,484, Method of Removing Tar from Gases (Piron, April 3, 1928); USP # 1,701,054, Purifying Gases (Piron, Feb 5, 1929); USP # 1,709,370, App. for Distillation (Piron, April 16, 1929); USP # 1,709,371, App. for Distilling Solids (Piron, April 16, 1929); USP # 1,733,750, Distillation App (Piron, Oct 29, 1929); USP # 1,794,542, Distilling Hydrocarbons (Piron, March 3, 1931).

Pittsburgh Coal Carbonizing Co: See Wisner

# 1217. Plassman
Brownlie, D.: Gas Age Rec 65: 541 (Apr 1930)
Ibid.: Gas Engr 42: 267 (Dec 1926)
Plassman, J.: Fuel 7: 325 (July 1928)

# 1218. Plauson
Tupholme, C.: Chem Met Eng 30: 861 (June 1924)

# 1219. Prudhomme
Stephan, M.: Oil Eng & Fin 6: 438 (Sep 1925)

Pure Coal Briquette Process: See Sutcliffe

# 1220. Raffloer
Coll Guard 131: 1023, 1162 (1926)
Ibid.: Iron Coal Trade Rev 1112: 223 (Feb 1926)
Thau, A.: Coal Age 20: 913 (1921)

[ # 1221a. Ramage
USP # 1,516,406, A. Ramage, App & Proc for Distillation of Coal (A. Ramage, Nov 18, 1924); USP # 1,812,372, Process (Ramage, June 30, 1931); USP # 1,926,455, App for LT Distillation (Ramage, Sept 12, 1933) ]

# 1221. Reed-Lamie
Power 72: 941 (Dec 1930)
USP # 1,696,730, process for Distilling Shale (H. Reed & R. Lamie, Dec 25, 1928); USP # 1,927,219, Coal Distilling App. (Reed & Lamie, Sept 19, 1933); USP # 1,980,828, App. & Proc. for distilling Coal (Reed & Lamie, Nov 13, 1934);

# 1222. Rexco (CRS)
Coal Carb 2: 73 (Apr 1936)
Fieldner, A.: USBM T.P. # 396 (1926)
Gavin, M.: USBM Bull 315 (1930)
Griggs, A.: Gas J.: 213: 824 (Mar 1936); ibid., 214: 41 (Apr 1936)
Ibid.: Fuel Econ. 11: 426 (1936)
Ibid.: Coll Guard 153: 1 (July 1936)
Petr Tech (1936), p. 273
Roberts, J.: Coal Carb 5: 13 (Jan 1939)
Warner, A.: Amer Gas Assn Proc 5: 928 (1923)
USP # 1,283,000, App for Removing Oils from Oil-Shale (G. Wallace, Oct 29, 1918); USP # 1,491,290, App for Distilling Oil Shales (D. Davis & Wallace, April 22, 1924); USP # 1,536,696, Proc of Carbonizing (Wallace, May 5, 1925); USP # 1,714,198, App for Treating Oils (Wallace, May 21, 1929); USP # 1,728,582, Carbonizing App (Sept 17, 1929); USP # 1,804,073, Carbonizing App (Wallace, May 5, 1931).

# 1223. Richards-Pringle
Brownlie, D.: Combustion 11: 354 (Nov 1924)

Rolle: See Geissen

# 1224. Roser
Harry, L.: Int Conf Bitum coal Proc 1: 436 (1931)

# 1225. Ryan
Brownlie, D.: Ind Eng Chem 28: 629 (June 1936)

# 1226. Salermo
Chem Age 22: 75 (Jan 1930)
Coll Guard 139: 1191, 1288 (Sep Oct 1929)
Eng 127: 701 (May 1929)
Inst Petr Tech (1926), p. 274
USP Re. 17,251 (USP # 1,541,071), Distillation App (P. Salerni, April 2, 1929); USP # 1,828,683, Distillation (E. Salerni, Oct 20, 1931); USP # 2,069,421, App for Distillation (Salerni, Feb 2, 1937).

# 1227. Sauerbrey
Brownlie, D.: Gas Age Rec 62: 857 (1928)
Thau, A.: Eng & Fin 21: 199, 259 (Oct Nov 1929)

# 1228. Seidenschnur-Pape
Fieldner, A.: USBM T.P. # 396 (1926)

# 1229. Sheffield

Smith: See Carboal

# 1230. Stansfield
Davis, J.: USBM R.I. # 2292 (1921)

# 1231. Stephenson
Brownlie, D.: Ind Eng Chem 28: 629 (June 1936); ibid., 29: 734 (Jul 1937)
Fischer, A.: Petr Times 36: 805 (1936)
Ibid.: Eng 144: 217 (Aug 1937)

# 1232. Stevens
Stevens, H.: Stevens, H.: Sci Amer 157: 270 (Nov 1937)

# 1233 Strevens
Brownlie, D.: Ind Eng Chem 2: 629 (June 1936)

# 1234. Struban
Brownlie, D.: Ind Eng Chem 28: 629 (June 1936)

# 1235. Summers
Davis, J.: USBM R.I. # 2292 (1921)

# 1236. Suncole
Brownlie, D.: Ind Eng Chem 19: 39 (Jan 1927)
Fieldner, A.: USBM T.P. # 396 (1926)
Ibid.: Iron Cal Trade Rev 111: 591 (Oct 1925); ibid., 123: 584 (Oct 1931)
Ibid.: Coll Guard 143: 1300 (Oct 193)
Ibid.: Eng 133: 65 (Jan 1932)
Nielsen, H.: Gas J (Lond) 198: 270(May 1932); ibid., 188: 589 (Nov 1929); 194: 483 (May 1931); ibid., 173: 202 (Jan 1926); ibid., 96: 120 (Feb 1932); ibid., 158: 446 (May 1922); ibid., 172: 654 (Dec 1925)
Ibid.: Coll Guard. 144: 776 (Apr 1932)
Ibid.: Mech World 86: 516, 540(Nov Dec 1929)
Ibid.: Iron Coal Trade Rev 104: 607 (1922)
Ibid.: Mech Eng 49: 1109 (Oct 1927)
Ibid.: Chem met Eng 29: 1008 (Dec 1923)
Ibid.: Uchida, S.: Eng 122: 720 (1926)
USP # 1,460,764, Stuffing Box (H. Nielsen & B. Layng, July 3, 1923); USP # 1,518,938, Rotary Retort (Nielsen, Dec 9, 1924); USP # 1,589,417, Rotary Distillation Retort (Nielsen, June 22, 1926); USP # 1,593,333, Process for LTC (J. Garrow, July 20, 1926); USP # 1,605,761, Treatment of Carbonaceous Material (Nielsen, Nov 2, 1926); USP # 1,654,942, Proc of Making Mixed Gas (Nielsen, Jan 3, 1928); USP # 1,718,830, App for Manufacturing Water Gas (Nielsen, June 25, 1929); USP # 1,830,884, Distillation of Carbonaceous Materials (Nielsen, Nov 10, 1931); USP # 1,866,262, Distillation (Nielsen, Nov 1, 1932); USP # 1,886,350, Method of Distilling (Nielsen, Nov 1, 1932); USP # 1,905,945, C. Machen, April 25, 1933); USP # 1,908,651, App for Distillation (Nielsen, May 9, 1933); USP # 2,112,401, App for Coking Briquettes (R. Hardy, March 29, 1938).

# 1237. Sutcliffe-Evans
Brownlie, D.: Ind Eng Chem 19: 39 (Jan 1927)
Ibid.: Coll Guard. 131: 1023, 1162 (1926)
Puening, F.: Chem Met Eng 26: 1086 (June 1922)
Ibid.: Soc Chem Ind J 43: 874 (Aug 1924)
Sutcliffe, E.: Electrician 95: 211 (1925)
Ibid.: Fuel 7: 326 (July 1928)
Tupholme, C.: Chem Met Eng 29: 401 (Sept 1923)
USP # 1,767,231, Distillation (E. Sutcliffe, June 24, 1930).

# 1238 Thermax
Petroleum 30: 1 (1934)

# 1239. Thomas
Thau, A.: Coal Age 20: 873 (Dec 1921)

# 1240 Thompson-Beeler
Brownlie, D.: Ind Eng Chem 28: 629 ( June 1936)

# 1241. Thyssen
Darrah, W.: Combustion 20: 179 (Apr 1929)
Ibid.: Int Conf Bitum Coal Proc, p. 242 (1928); Ibid., p. 746 (1931)
Harry, L.: Int Conf Bit Coal Proc, p. 436 (1931)
Hood, O.: USBM Bull # 255 (1926)
Mueller, F.: Int Conf Bit Coal Proc , p. 766 (1926)
Thau, A.: Coal Age 20: 873 (Dec 1921)

# 1242. Tormin
Brownlie, D.: Mech Eng 52: 224 (Mar 1930)

Tozer: See Carlton

# 1243. Traer
Davis, J.: USBM R.I. # 2292 (1921)
Traer, G.: AIME Bull # 141: 1463 (Sept 1918); ibid., Bull # 145: 98 (Jan 1919)

# 1244. Trent
Davis. J.: Chem Met Eng 25: 1131 (1921)
Ibid.: USBM R.I. # 2301 (1921)
Hall, R.: Coal Age 29: 112 (Jan 1926)

# 1245. Trentha
Fuel Econ 10: 820 (Apr 1935)

# 1246. Trumble
Brownlie, D.: Mech Eng 59: 772 (Oct 1937)
Ibid.: Gas Engr 42. 267 (Dec 1926)
Taylor, J.: Int Conf Bitum Coal Proc., p. 474, 488 (1928)
USP # 1,514,113, Proc for Oil Sands (M. Trumble, Nov 4, 1924); USP # 1,555,531, Distillation App (Trumble, Sept 29, 1925);  USP # 1,586,131, App for Producing Solid Fuel (Trumble, May 25, 1926); USP # 1,598,831, Process (Trumble, Sept 7, 1926); USP # 1,651,647, Apparatus (Trumble, Dec 6, 1927); USP # 1,653,137, Removable Cover Construction (Trumble, Dec 20, 1927); USP # 1,659,930, Combined Distilling & Cracking Proc (Trumble, Feb 21, 1928); USP # 1,667,403, Method of Producing Power (Trumble, April 24, 1928); USP # 1,674,420, Process (Trumble, June 19, 1928); USP # 1,676,675, Process (Trumble, July 10, 1928); USP # 1,704,956, Process (Trumble, March 12, 1929); USP # 1,713,794, Method for Operating Battery of Retorts (Trumble, May 21, 1929); USP # 1,714,963, Process (Trumble, May 28, 1929); USP # 1,724,982, Oil-Cracking Means (Trumble, Aug 20, 1929); USP # 1,725,320, Hydrogenating & Cracking Organization (Trumble, Aug 20, 1929); USP # 1,836,051, Shale Distillation (Trumble, Dec 15, 1931); USP # 1,873,910, Process (Trumble, Aug 23, 1932).

# 1247. Turner
Brownlie, D.: Mech Eng 59: 772 (Oct 1937)
Ibid.: Gas Age Rec 65: 165 (Feb 1930)
Sanders, A.: Iron Coal trade Rev 114: 520 (Apr 1927)
Turner, C.: Fuel 7: 328 (July 1928)
Ibid.: Eng 123: 559 (May 1927)
Ibid.: Coll Guard. 133: 749 (Apr 1927)
Ibid.: Coll Eng  4: 152 (Apr 1927)
Ibid.: Gas J 189: 639 (Mar 1930)

Vandegrift: See Bituminoil
Wallace: See Rexco

# 1248. Warner
Gas J (Apr 1925), p. 185

# 1249. Whitaker-Pritchard
Pritchard. T.: Chem Met Eng 23: 664 (Oct 1920)

# 1250. White
Hobart, F.: Mech Eng 54: 286 (Apr 1932)
White, A.: Gas Age Rec Dec 1026)
Ibid.: Int Conf Bit Coal Proc., p 419 (1926)
USP # 1,782,556, Coke & Process (A. White, Nov 25, 1930).

# 1251. Winzer
Brownlie, D.: Ind Eng Chem 19: 39 (Jan 1927) ; ibid., 41: 215-217 Suppl (1938);
Ibid.: Gas Age Rec 62: 39 (July 1928)
USP # 1,929,132, App for Carbonization (C. Winzer, Oct 3, 1933).

# 1252. Wisner
Allen, A.: Int Conf Bit Coal Proc., p. 403 (1928)
Hood, O.: USBM Bull #  255 (1926)
Lesher, C.: Coal Age 44: 45 (March 1939); ibid., 41: 66 (1936)
Ibid.: Coll Eng 7: 67 (Feb 1930)
Wisner, C.: Amer Gas J 125: 628 (Nov 1926)
Ibid.: Combustion 16: 42  (Jan 1927)

Woiduch: See Carbonol

# 1253. Wollaston
Brownlie, D.: Ind Eng Chem 19: 39 (Jan 1927)

By-Products ~

# 1254. Ando, S.: Soc Chem Ind Jap J 40: 83, 124 Suppl (1937); ibid., 41: 126, 191-193, 215-217 Suppl (1938); ibid., 37:357B (July 1934)
# 1261. Ibid.: Fuel Soc Jap J 17: 33 (1938)
# 1262. Ibid.: Chem Age 38: 423 (1938)
# 1263. Ban, Y.: Fuel Soc Jap J 7: 57 (July 1928)
# 1265. Bidulph-Smith, T.: Gas World 84: 20 (May 1926)
# 1266. Bing, J.: Int Conf Bit Coal Proc 1926, p. 404
# 1267. Blakely, T.: Soc Chem Ind J 57: 7 (1938)
# 1268. Blauvelt, W.: Franklin J Inst 202: 307 (Sep 1926)
# 1269. Burnstein, E.: Nature 121: 356 (1928)
# 1270. Bristow, W.: Inst Petr Tech J 22: 583 (Aug 1936)
# 1271. Brittain, A.: Fuel 4: 263 , 299, 337 (Jun Jul Aug 1925)
# 1272. Brown, J.: Roy Tech Coll J (Glasgow) 4: 76 (1927)
# 1272. Brown, R.: Ind Eng Chem 20: 392 (Apr 1928); ibid., 19: 26 (Jan 1927)
# 1275. Ibid.: Coal Age 29: 905 (Jun 1926)
# 1277. Ibid.: Ind Eng Chem 21: 234 (Apr 1929)
# 1278. Burke, S.: Ind Eng Chem 19: 34 (Jan 1937)
# 1279. Burrell, G.: Fuel 7: 416, 463 (1928)
# 1280. Caplan, S.: Ind Eng Chem Ann Ed 6: 7 (Jan 1934)
# 1281. Cawley, C.: Soc Chem Ind J 56: 445T (Dec 1937)
# 1282. Ibid.: Fuel Res Board T.P.  # 45 (1937)
# 1283. Cheng, Y.: Gas Age Rec 59: 737, 779, 815, 851 (May Jun 1927)
# 1284. Church, S.: Ind Eng Chem 19: 31 (Jan 1927)
# 1285. Ibid.: Chem & Met Eng 32: 869 (Nov 1925)
# 1288. Conway, M.: Chem Age 21: 307 (Oct 1937)
# 1289. Currey, G.: Soc Chem Ind J 42: 379T (Sep 1923)
# 1290. Curtis, H.: Chem Met Eng 33: 666 (Nov 1926)
# 1292. Davis, J.: Fuels & Furn 1: 247, 336 (1923)
# 1293. Ibid.: Carnegie Inst Tec & USBM Coop Bull # 1 (1922)
# 1294. Davis, J.: Amer Gas Assn Proc (1925), p. 887
# 1295. Ibid.: Ind Eng Chem 23: 186 (Feb 1931)
# 1296. Ibid.: Eng & Fin. 21: 85 (Aug 1929)
# 1299. Duder, J.: Thesis BS, Univ Utah (1937)
# 1300. Dunstan, A.: Int Conf Bit Coal Proc (128) p 210
# 1301. Ibid.: Ind Chem 4: 109 (Mar 1928)
# 1302. Edwards, K.: Soc Chem Ind J 43: 143, 149 (1924)
# 1303. Egloff, G.: Inst Conf Bit Coal Proc (1926) p 788
# 1305. Fieldner, A.: Nucleus 4: 20 (Feb 1927)
# 1306. Ibid.: USBM R.I. # 3079 (1931)
# 1307. Ibid.: Fuel 7: 492 (Nov 1928)
# 1308. Fisher, C.: USBM  Bull # 412 ( 1938)
# 1309. Foxwell, G.: Coal Carb. 2: 194 (1936)
# 1310. Ibid.: Chem Age (Lond) 36: 410 (May 1937)
# 1311. Ibid.: Gas World 89: 13 (July 1928)
# 1312. Franta, W.: Ind Eng Chem 29: 1182 (Oct 1937)
# 1313. Frey, F.: Ind Eng Chem 19: 21 (Jan 1927); ibid., 19: 488 (Apr 1927)
# 1315. Gray, W.: Gas Age Rec 55: 799 (June 1925)
# 1316. Ibid.: Fuel Res Board T.P. # 40 (1935); ibid., # 32 (1931)
# 1318. Gas Age Rec 58: 731 (Nov 1926)
# 1319. Gunderson, R.: Ind Chem 3: 397 (Sept 1927)
# 1320. Hall, C.: Soc Chem Ind J 56: 303T (Sept 1937)
# 1321. Hall, F.: Chem Age 34: 48 (Jan 1936)
# 1323. Hicks, D: Fuel Res Bd T.P.  # 34 (1931)
# 1324. Ibid.: Eng. 132: 737 (Dec 1931)
# 1324a. Ibid. Gas J (Lond) 196: 731 (Dec 1931)
# 1325. Ibid.: Petr. Times 26: 768 (1931)
# 1326. Ibid.: Combustion 18: 190 (Mar 1928)
# 1327. Hofmann, F.: Int Conf Bit Coal Proc (1928),p. 119
# 1328. Hollinger, H.: Soc Chem Ind J 45: 406 (Nov 1926)
# 1329. Horne, J.: USBM R.I. # 2832 (1927)
# 1330. Hurley, T.: Soc Chem Ind J 50: 584 (July 1931)
# 1331. Joiner, W.: Gas World 94: 729 (June 1931)
# 1332. Jones, D.: Soc Chem Ind J 36: 3 (1917)
# 1333. Jones, W.: Gas World 93: 106 (Aug 1930)
# 1334. Kester, E.: Carnegie Inst & USBM Coop Bull  # 54 (1932)
# 1335. Ibid.: Fuel 11: 25 (Jan 1932)
# 1336. Ibid.: Ind Eng Chem An Ed 3: 292 (July 1931)
# 1337. Ibid.: Gas Engr 48: 667 (Nov 1931)
# 1338. Ibid.: USBM R.I. # 3171 (1932)
# 1339. Kimura, I.: Fuel Soc Jap J 6: 3 (Feb 1927)
# 1341. King, J.: Soc Chem Ind J 46: 181T (May 1927)
# 1343. Mining Rev 35: 5 (Feb 1933)
# 1344. Kirby, W.: Soc Chem Ind J 46: 422 (May 1927)
# 1345. Komatsu, S.: Cehm Soc Jap J 57: 722 (1931)
# 1347. Kosaka, Y.: Soc Chem Ind Jap J 34: 345 B (Oct 1931)
# 1348. Kurihara, K.: Fuel Soc Jap J 7: 61 (July 1928)
# 1349. Lander, C.: Inst Petr Tech J 13: 149 (Apr 1927)
# 1350. Lewis, G.: Fuel Econ 1: 365 (1926)
# 1351. Ibid.: Coll Guard 143: 1622 (Nov 1931)
# 1352. Ibid.: Eng 133: 57 (Jan 1932)
# 1253. Manning, A.: Chem Soc J 132: 1014 (1929)
# 1354. Mathews, M.: Inst Petr Tech J 18: 415 (May 1932)
# 1355. Morgan, G.L Soc Chem Ind J 51: 67 T (Feb 1932)
# 1356. Ibid.: Soc Chem Ind J 51: 67T (Feb 1932); ibid., 51: 67T (Feb 1932)
# 1358. Ibid.: Fuel 10: 183 (Apr 1931)
# 1359. Morgan, G.: Soc Chem Ind J 53T, 73T (Mar 1934); ibid., 50: 191T (June 1931); ibid., 50: 721 (Feb 1931); ibid., 56: 109T (Apr 1937); ibid., 54: 19T, 22T (Jan 1935); 48: 89T (May 1929); ibid., 48: 29T (Feb 1929); ibid.,  57: 152 (1938); ibid., 51: 80T (Feb 1932); ibid., 42: 1178 (1923)
# 1364. Ibid.; Nature 121: 357 (1928)
# 1371. Morgan, J.: Gas Age Rec 68: 147, 195 (Aug 1931)
# 1372. Ibid.: Ind Eng Chem 15: 587, 693 (June July 1934)
# 1373. Ibid.: Chem Met Eng 26: 923, 977 (May 1922)
# 1374. Morrell, J.: Ind Eng Chem J 17: 473 (May 1925)
# 1375. Ibid.: Eng. 132: 737 (Dec 1931)
# 1376. Nash, A.: Coll Guard. 144: 550 (1932)
# 1377. Ibid.: Int Conf Bitum Coal Proc (1938) p 928
# 1378. Newall, H.: Fuel Res Bd T. P. # 48 (1938)
# 1379. Nielsen, H.: Gas J 174: 591, 650, 732 (1926)
# 1380. Ibid.: Mech Eng 49: 1109 (Oct 1927)
# 1381. Parr, S.: Illin Univ Eng Exp Stn Bull # 60 (1912)
# 1382. Parrish, E.: Fuel 5: 436 (1926)
# 1383. Parrish, R.: Soc Chem Ind J 45: 99T (Apr 1926)
# 1384. Ibid.: Eng 144: 488 (Oct 1937)
# 1385. Ibid.: Coal Carb. 4: 160 (Oct 1938)
# 1386. Perkin, F.: Oil Gas J 25; 179 (1926)
# 1387. Ibid.: Oil Eng Tech 7: 527 (1926)
# 1388. Pratt, D.: Fuel 10: 243 (June 1931)
# 1390. Roskill, O.: Gas World 104: 589 (June 1936)
# 1391. Schneider, E.: USBM R.I. # 2968 (1930)
# 1392. Shimimura, K.: Fuel Soc Jap J 6: 50 (June 1927)
# 1393. Sinnatt, F.: Gas J 208: 433 (Nov 1934)
# 1394. Ibid.: Gas World 101: 556 (Nov 1934)
# 1395. Ibid.: Soc Chem Ind J 44: 413T (1925); ibid., 45: 385T (Nov 1926)
# 1397. Ibid.: Gas J 217: 843 (Mar 1937); ibid., 189: 92 (Jan 1930)
# 1399. Ibid.: Coll Guard. 139: 2169 (Dec 1929)
# 1400. Stuart, M.: Fuel 9: 463 (Oct 1930)
# 1401. Tashiro, S.: Fuel Soc Jap J 7: 67 (July 1928); ibid., 9: 102 (Nov 1930)
# 1403. Thau, A.: Coal Age 20: 913 (Dec 1921)
# 1404. Tupholme, C.: Chem Ind 38: 469 (May 1936)
# 1405. Ibid.: Chem Met Eng 32: 360 (Mar 1925)
# 1406. Ibid.: Ind Eng Chem 16: 221 (Apr 1938)
# 1408. Warren, T.: Canada Dept mines Publ # 737 (1934)
# 1409. Weiss, J.: Int Conf Bitum Coal Proc pg 449 (1926)
# 1410. Ibid.: Combustion 18: 182 (Mar 1928)
# 1412. Wiltshire, J.: Soc Chem Ind J 50: 125T

Cancer Caused By Derivatives of C oal Tar ~ [ Not included here]

Oil Shale (Testing & Processing) ~

# 1676. Anderson, L.: Thesis MS, Univ Utah (1920)
# 1682. Botkin, C.: Chem Met Eng 26: 398 (Mar 1922)
# 1683. Bowie, C.: USBM T.P. # 370 (1926)
# 1684. Brownlie, D.: Soc Chem Ind J 53: 827 (Oct 1934)
# 1685. Caracristi, V.: Combustion 10: 336 (May 1924)
# 1690. Church, E.: Amer Gas Eng J 112: 117 (Feb 1920)
# 1695. Crozier, R.: Mining Mag 29: 265 (Nov 1923)
# 1705. Finley, W.: USBM T.P. # 398 (1926)
# 1706. Ibid.: USBM R.I. # 2603 (1924)
# 1719. Gavin, M.: USBM Bull # 315 (1930)
# 1721. Ibid.: USBM R.I. # 2588 (1924); ibid., # 2254 (1920)
# 1725. Gilmore, R.: Oil & Gas J 26: 154 (Oct 1927)
# 1726. Ibid.: Can Chem & Met 9: 215, 235 (Oct Nov 1925)
# 1727. Goodwin, C.: Chem Age (Lond) 6: 515 (Apr 1922)
# 1739. Horne, J.: USBM R.I. # 2603 (1924)
# 1748. Jenson, J.: Chem Age (NY) 28: 313 (Sep 1920)
# 1749. Karrick, L.: USBM R.I. #2229 (1921); ibid., #2456 (1923); ibid., 2324 (1922)
# 1752. Ibid., USBM Bull # 249 (1926)
# 1753. Ibid.: Thesis MS, Univ Utah (1921)
# 1766. Meyer, J.: Oil & Gas J 23: 92 (Oct 1924)
# 1772. Nash, A.: Chem Age (NU) 31: 9 (Jan 1923)
# 1787. Remington, I.: Fuel Econ 10: 1014 (Sep 1935)
# 1800. Stainer-Hutchins, T.: Petr Times 8: 823 (Dec 1922)
# 1803. Stewart, R.: Mining Rev 29: 25 (Sep 1927)
# 1812. Wallace, G.: Chem Age (Lond) 9: 614 (Dec 1923)
# 1813. Ibid.: Chem Met Eng 32: 237 (Feb 1925)
# 1814. Ibid.: Combustion 19: 87 (Aug 1928)
# 1815. Ibid.: Chem Age (Lond) 12: 196 (Feb 1925)




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