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The
Technology
of
Low Temperature Carbonization
by
Frank M. Gentry
1928
Preface
So far as the author is aware, this is the first book in America dealing exclusively with the subject of low temperature carbonization and the first relating solely and comprehensively to its technology. A great amount of data have been made available to the industry, but heretofore little effort has been made to collect and correlate them so that they might be of maximum value to the art. Consequently, it is anticipated that this book will fill a vacancy in the literature relating to the carbonization industry.
More properly, perhaps, this volume should be entitled "Technology of Carbonization with Special Reference to Low Temperature Carbonization", because the principles of distillation at low temperatures are identical with the technology underlying the initial stages of carbonization at medium and at high temperatures. The technical differences between high and low temperature carbonization lie in the extent to which distillation is carried, by regulation of temperature and time, and in the procedure adopted for carrying the process to completion.
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. The justification of this book rests upon its effort to treat these subjects in such a way as to establish the art upon a scientific basis, so that, henceforth, empirical methods may be reduced to a minimum.
The economical aspects of low temperature carbonization is the one restraining feature in the advance of the industry in the United States today, but this does not apply to other countries such as England, France, and Germany, which are not so generously endowed with petroleum and other high grade fuel resources. Because of its controversial nature at this time, the author has deemed it advisable not to treat at length the subject of economies to be derived from carbonization at low temperatures, but to adhere as far as possible to the technical aspects of the art. In due course of events, progress in the art will demonstrate just what place low temperature carbonization will occupy in the industrial organization of each nation. When this position becomes clearly defined the subject of economics can be treated more adequately without the necessity of discounting figures, glorified by promotion and minimized by competitive enterprises.
As a word of caution, the author takes this occasion to point out the great care necessary in reviewing the literature on low temperature carbonization. Many articles have been reprinted in the United States from English sources in which British gallons have not been converted to United States gallons. Many yields per ton of coal are quoted without specifying whether it be long tons, short tons, or metric tons. The tar yields are sometimes reported as wet tar and sometimes as dry tar, without indication of which. Calorific tar of the gas is reported for either the scrubbed or unscrubbed gas, usually leaving the reader to judge by the figure which value it is. Unless otherwise specified, the figures herein given have been corrected to short tons, dry tar, and United States gallons, as far as was possible from the reports of the authorities.
F.M.G.
March 1928
[ Note: The quality of the scanned graphics (tables & figures) are "uneven" at best despite repeated efforts to scan and tweak the images.-- R.N. ]
~ Contents ~
Historical ~ Solid Fuels ~ Origin of Coal ~ Constitution of
Coal ~ Destructive Distillation ~ Low Temperature Carbonization
~ Chemistry ~ Coal Assay ~ Thermochemistry ~ Heat Balance ~
Catalysis ~ Plastic Layer ~
Internal & External Heating ~ High & Low Temperature
Carbonization
Evolution of Gas ~ American Coals ~ British Coals ~ Peat &
Lignite ~ Shale ~ Time Effect ~ Vacuum Effect ~
Secondary Decomposition ~ Gaseous Atmospheres ~ Steaming ~
Physico-Chemical Equilibrium
Eduction of Primary Tar ~ Time Effect ~ Pressure & Vacuum
Effect ~ Atmospheric & Moisture Effect ~
Constitution of Primary Tar ~ Identification of Compounds ~ Tar
Acids ~ Tar Bases ~ Tar Solids, Sulfur, & Liquor ~ Primary
Tar Fractionation ~ Steam Distilled Tar ~ Full-Scale Retort Tar
~ Tar Cracking ~ Cracked Tar Gas ~ Hydrogenation ~ Motor Fuel ~
Fuel oil
High & Low Temperature Coke ~ Semi-Coke ~ Porosity ~
Coherency ~ Swelling ~ Preheating & Oxidation ~
Coke Reactivity ~ Coke Combustibility ~ Coke Strength ~
Temperature Effect ~ Semi-Coke Uses ~ Domestic Fuel ~ Power Char
Distribution of Nitrogen ~ Effect of Temperature ~ Ammonium
Sulfate ~ Thermal Decomposition ~ Rate of Decomposition ~
Ammonia Oxidation ~ Nitrogen & Hydrogen Atmospheres ~
Steaming ~ Sulfur Distribution ~
Thermal Transformations ~ Temperature Effect ~ Desulfurization
Adaptability of Processes ~ Classification of Processes ~ Carbocoal-McIntire Processes ~ Coalite Processes ~ Freeman Process ~ Fuel Research Board Processes ~ Fusion Process ~ Greene-Lauck Process ~ KSG Process ~ Maclaurin Process ~ Nielsen Process ~ Piron-Caracristi Process ~ Sutcliffe-Evans Process ~ Tozer Process
General ~ Operation of Retorts ~ Design of Retorts ~ Materials
of Construction ~ Refractory Retorts ~ Properties of
Refractories ~ Metallic Retorts ~ Properties of Cast-Iron ~
Properties of Steel ~ Heating of Retorts
Convection & Radiation
Yields ~ Revenue from Operation ~ Capital & Operating Costs ~ Economics ~ The Coke Market ~ The Gas & Light Oil Markets ~ The Tar Market ~ The Fixed Nitrogen Market ~ Potential Markets ~ Central Station By-Product Recovery ~ Plant Location ~ Fuel Resources ~ Conclusion
Illustrations
Frontispiece: Battery of Carbocoal Primary Retorts,
Clinchfield, VA
Fig. 1 ~ The Approved Apparatus for Destructive Distillation of
Coal in 1810
Fig. 2 ~ Heat Liberated from American Coals as a Function of
Temperature
Fig. 3 ~ Heat Liberated from Peat & Sawdust as a Function of
Temperature
Fig. 4 ~ Resistance of Plastic Layer to Gas Flow as a Function
of Oxidation
Fig. 5 ~ Progression of Plastic Layer Across Coke Oven as a
Function of Time
Fig. 6 ~ Rate of Travel of Plastic Layer Across Coke Oven as a
Function of Distance
Fig. 7 ~ Temperature of Charge in High & Low Temperature
Retorts as a Function of Time
Fig. 8 ~ Isotherms of a Coke Oven as a Function of Time
Fig. 9 ~ Effect of Steam Admission on the Distribution of
Temperature in Vertical Retorts
Fig. 10 ~ Composition of Gas from Pennsylvania Coal as a
Function of Temperature
Fig. 11 ~ Composition of Gas from Illinois Coal as a Function of
Temperature
Fig. 12 ~ Composition of Gas from N Carolina Coal as a Function
of Temperature
Fig. 13 ~ Composition of Gas from Wyoming Coal as a Function of
Time
Fig. 14 ~ Total Yield of Gas from Pennsylvania & Wyoming
Coal as a Function of Time
Fig. 15 ~ Composition of Coke Oven Gas as a Function of Time
Fig. 16 ~ Initial Absorption of Heat from a Retort Wall
Fig. 17 ~ Rate of Gas Evolution & Caloric Value as a
Function of Time
Fig. 18 ~ Volatile Matter Deposited as Tar as a Function of C-H
Ratio
Fig. 19 ~ Yield of Tar from Welsh Coals as a Function of
Temperature
Fig. 20 ~ Yield of Tar from American Coals as a Function of
Temperature
Fig. 21 ~ Yield of Tar from American Coals in Vacuo as a
Function of Temperature
Fig. 22 ~ Distribution of Low Temperature Tar Acids as a
Function of Boiling Point
Fig. 23 ~ Distribution of Low Temperature Tar Bases as a
Function of Boiling Point
Fig. 24 ~ Boiling Range of Low Temperature Tar, Shale Oil, &
Petroleum
Fig. 25 ~ Boiling Range of Low Temperature Tars from
Pennsylvania Coals
Fig. 26 ~ Boiling Range of Shale Oil Fractions & of American
Gasoline
Fig. 27 ~ Boiling Range of Steam Distilled Low Temperature Tar
as a Function of Temperature
Fig. 28 ~ Boiling Range of Vacuum Fractionated Steam Distilled
Tar as a Function of Cracking Temperature
Fig. 29 ~ Light Oil & Fixed Gas from Low Temperature Tar as
a Function of Cracking Temperature
Fig. 30 ~ Reaction Temperature of Berginization & Cracking
as a Function of Time
Fig. 31 ~ Swelling in Loire Coal as a Function of Temperature
& Time
Fig. 32 ~ Swelling in Bethune Coal as a Function of Temperature
& Rate of Heating
Fig. 33 ~ Comparison of Loss in Weight & of Swelling in
Durham Coal as a Function of Temperature
Fig. 34 ~ Swelling in Varennes Coal as a Function of Temperature
& of Oxidation
Fig. 35 ~ Swelling in Varennes Coal as a Function of Temperature
& of Preheating
Fig. 36 ~ Evolution of Carbon Dioxide from Illlinois Coal
Lignitic Residue as a Function of Temperature
Fig. 37 ~ Evolution of Carbon Dioxide from Illlinois Bituminic
Extract as a Function of Temperature
Fig. 38 ~ Proportion of Oxygen & Carbon Dioxide in
Combustion Gases from Various Fuels
Fig. 39 ~ Crushing Strength of Cokes as a Function of Heating
Fig. 40 ~ Yield & Analysis of Semi-Coke under Steam
Distillation as a Function of Temperature
Fig. 41 ~ Yield of Products from Silesian Coal as a Function of
Temperature
Fig. 42 ~ Yield of Ammonium Sulfate as a Function of Temperature
Fig. 43 ~ Catalytic Effect of Iron & Porcelain on Ammonia
Decomposition as a Function of Temperature
Fig. 44 ~ Catalytic Effect on Chattered Firebrick in Various
Atmospheres on Ammonia Decomposition
Fig. 45 ~ Oxidation of Ammonia in Dry & Moist Air as a
Function of the Rate of Flow
Fig. 46 ~ Catalytic Effect of Chattered Firebrick on the
Destruction of Ammonia as a Function of Temperature
Fig. 47 ~ Evolution of Ammonia from High Temperature Coke in
Atmospheres of H & of N
Fig. 48 ~ Evolution of Ammonia from High Temperature Coke in an
Atmosphere of H & Steam
Fig. 49 ~ Evolution of Ammonia from Low Temperature Coke by
Successive Heating at 800 C in Various Atmospheres
Fig. 50 ~ Evolution of Ammonia from Low Temperature Coke Heated
Successively at Various Temperatures
Fig. 51 ~ Evolution of Ammonia from Low temperature Coke in
Various Atmospheres as a Function of Time
Fig. 52 ~ Evolution of Hydrogen Sulfide from Coke by Purging as
a Function of Time
Fig. 53 ~ Evolution of Hydrogen Sulfide from Low Temperature
Coke heated Successively at 800 C in Various Atmospheres
Fig. 54 ~ Evolution of Hydrogen Sulfide from Low
temperature Coke in an H Atmosphere at Various Temperatures
Fig. 55 ~ Evolution of Hydrogen Sulfide from Gas Coke in a
Hydrogenous Atmosphere at Various Temperatures
Fig. 56 ~ Evolution of Hydrogen Sulfide from High-Temperature
Coke in an Atmosphere of H & Steam
Fig. 57 ~ Carbocoal Primary Retort
Fig. 58 ~ Carbocoal Secondary Retort
Fig. 59 ~ McIntire Primary Retort
Fig. 60 ~ Davidson Modification of Coalite Retort
Fig. 61 ~ Freeman Retort
Fig. 62 ~ Fuel Research Board Horizontal Retort
Fig. 63 ~ Fuel Research Board Vertical Retort
Fig. 64 ~ Fusion Retort
Fig. 65 ~ Greene-Laucks Retort
Fig. 66 ~ KSG Retort
Fig. 67 ~ Maclaurin Retort
Fig. 68 ~ McEwen-Runge Process
Fig. 69 ~ Nielsen Process
Fig. 70 ~ Pioron-Caracristi Retort
Fig. 71 ~ Sutcliffe-Evans Retort
Fig. 72 ~ Tozer Retort
Fig. 73 ~ Thermal Conductivity of Refractories as a Function of
Temperature
Fig. 74 ~ Thermal Diffusivity of Refractories as a Function of
Temperature
Fig. 75 ~ Mean Specific Heat of Refractory & Ferrous
Materials as a Function of Temperature
Fig. 76 ~ Linear Expansion of Refractories as a Function of
Temperature
Fig. 77 ~ Tensile Strength of Malleable Iron, Semi-Steel &
Cast Iron as a Function of Temperature
Fig. 78 ~ Growth of Cast-Iron as a Function of Temperature &
Number of Heatings
Fig. 79 ~ Tensile Strength of Carbon & Alloy Steels as a
Function of Temperature
Fig. 80 ~ Linear Expansion of Ferrous Metals as a Function of
Temperature
Frontispiece: Battery of Carbocoal Primary Retorts,
Clinchfield, VA