STATE OF ILLINOIS DEPARTMENT OF REGISTRATION AND EDUCATION DIVISION OF THE STATE GEOLOGICAL SURVEY FRANK W. DE WOLF, Chief Cooperative Mining Series BULLETIN 21 THE MANUFACTURE OF RETORT GOAL- GAS IN THE CENTRAL STATES USING LOW-SULPHUR COAL FROM ILLINOIS, INDIANA AND WESTERN KENTUCKY By W. A. J)DNKLEY, State Geological Survey and W. W. ODELL; U. S. Bureau of Mines ILLINOIS MINING INVESTIGATIONS Prepared under a cooperative agreement between the Illinois State Geological Survey Division, the Engineering Experiment Station of the University of Illinois, and the U. S. Bureau of Mines, ^csbskSs : PKINTED BY ATTTHOKITY OF THK STATK OK ILLINOIS URBAnA, ILLINOIS 1918 ILLINOIS MINING INVESTIGATIONS Cooperative Agreement GAS SECTION The difficulty, due. to war conditions, of obtaining adequate and reliable delivery of eastern gas-coal and of coke has sug- gested the wider use in gas manufacture of low^-sulphur coal mined in the* central district, comprising Illinois, Indiana, and western Kentucky. The needs of the gas industry, and the desire of the U. S. Fuel Administration to meet those needs, has led to the appoint- ment by Governor Frank 0. Lowden, of a Technical Committee on Gas, By-products, and Public Utilities, to act in an advisory relation. The committee includes representatives of the Illinois Gas Association, the U. S. Bureau of Mines, the Engineering Experiment Station of the University of Illinois, and the State Geological Survey Division of the Department of Registration and Education, State of Illinois. Previously, some studies of the use of Illinois coal in retort- gas manufacture and in by-product coke ovens, and of the chem- ical and physical properties of Illinois coal, have been conducted under the Illinois Mining Investigations, cooperative agreement, — a joint agency of the U. S. Bureau of Mines, the University of Illinois, and the State Geological Survey Division. The continua- tion and expansion of this work has been recommended by the Technical Committee and the Fuel Administration. In response a Gas Section has been created, and experienced gas engineers, chemists, and other specialists have undertaken a program of experiment on a commercial scale to extend the use of central dis- trict coal in water-gas generators and in gas retorts. The results of the investigations will be published, and, in addition, the operators of gas plants in the region naturally trib- utary to central-district coal will be advised by the Technical Committee, of the progress from time to time, and will be urged to witness and participate in the tests and to introduce in their own plants new or improved practices which will lessen the bur- den on the railroads, and assist the mines and the coke ovens to meet the unprecedented demands due to the war. Inquiries and suggestions regarding the gas experiments should be addressed to Gas Section, Room 305 Ceramics Bldg., Urbana, Illinois. 3 3051 00006 4067 STATE OF ILLINOIS DEPARTMENT OF REGISTRATION AND EDUCATION DIVISION OF THE STATE GEOLOGICAL SURVEY FRANK W. DE WOLF, Chief Cooperative" Mining Series BULLETIN 21 THE MANUFACTURE OF RETORT GOAL- GAS IN THE GENTRAL STATES USING LOW-SULPHUR GOAL FROM ILLINOIS, INDIANA AND WESTERN KENTUGKY By W. A. DUNKLEY, State Geological Survey and W. W. ODELL; U. S. Bureau of Mines ILLINOIS MINING INVESTIGATIONS Frepared under a cooperative agreement between the Illinois State Geological Survey Division, the Engineering Experiment Station of the University of Illinois. and the U. S. Bureau of Mines. PRINTED BY AUTHORITY OF THE STATE OK ILLINOIS IJKBANA. ILLINOIS 1918 STATE OF ILLINOIS DEPARTMENT OF REGISTRATION AND EDUCATION DIVISION OF THE STATE GEOLOGICAL SURVEY Frank W. DeWolf, Chief Committee of the Board of Natural Resources and Conservation Francis W. Shepardson, Chairman Director of Registration and Education David Kinley Representing the President of the Uni- versity of Illinois Thomas C. Chamberlin Geologist CONTENTS PAGE War adjustment of gas-coal distribution 9 Present use of central district coal 9 Problems in the use of central district coals in coal-gas manu- facture 11 Price and availability of coals 11 Plant capacity 11 Operating labor 14 Disposal of coke 14 Purification 14 Operating methods 15 Results reported from central district coals 17 Economical advantage of central district coals for coal-gas manu- facture 19 Cost of materials 20 Operating labor costs 21 Repair costs 21 Overhead and miscellaneous expense 22 Income from residuals 22 Summary of costs 23 Summary 24 (5) Digitized by the Internet Archive in 2012 with funding from University of Illinois Urbana-Champaign http://archive.org/details/manufactureofret21dunk ILLUSTRATIONS FIGURE PAGE 1. Bituminous coal zone C 8 2. Bituminous coal zone D 10 3. Bituminous coal zone E 13 TABLES 1. Results of retort-gas practice with central district coals from Illinois 18 2. A comparison of the approximate manufacturing costs of gas from central district and eastern gas-coals 23 (7) Fig. 1. — Bituminous coal zone C, established by the U. S. Fuel and the U. S. Railroad Administrations, April 1, 1918, and corrected to July 1. 1918. Includes low-sulphur coal areas in southern Illinois. During the period from October 1, 1918 to March 31, 1919, producing districts of Illi- nois, shown in black, are restricted in their shipments of coal to markets within and along the solid boundary line. During the period from April 1, 1918, to September 30, 1918, these same districts are restricted in their shipments to markets within and along the heavy dashed boundary line and its solid continuation south from Albia, Iowa, and Milwaukee, Wisconsin. During the entire year the producing districts of Vermilion County, Illinois, along the Wabash Railway may in addition ship coal to points of delivery along the Wabash Railway THE MANUFACTURE OF RETORT GOAL-GAS IN THE CENTRAL STATES USING LOW-SULPHUR COAL FROM ILLINOIS, INDIANA AND WESTERN KENTUCKY By W. A. Dimkley, State Geological Survey, and W. W. Odell, U. S. Bureau of Mines WAR ADJUSTMENT OF GAS-COAL DISTRIBUTION Eastern gas coals, because of their high yield of gas and of excellent coke, have hitherto been used almost exclusively for re- tort coal-gas manufacture in the central west as well as in the east. However, the necessity of avoiding long freight hauls wherever possible, and of conserving the supply of eastern coals for the manufacture of metallurgical coke and for eastern gas requirements makes it a patriotic duty to utilize as far as possible the great but comparatively undeveloped resources of low-sulphur coal in the central states. Gas plants in zones C, D, and E of the U. S. Fuel Admini- stration (figs. 1, 2, and 3 and explanations of subsequent changes) should naturally use coal mined within the zones if possible, rather than request coal under permit from distant sources. The term "central district" coal as used in this paper includes that from Illinois, Indiana, and western Kentucky. Although both commercial and technical problems must be solved before these coals are generally used in gas manufacture, reliable data already collected warrant further effort and prom- ise success. PRESENT USE OF CENTRAL DISTRICT COAL The use of central district coals in gas making is by no means new. These coals have been used in a majority of the 20 repre- sentative plants recently inspected in Illinois, Iowa, and Wiscon- sin. Depending upon local conditions, the results obtained vary considerably and are in general agreement with those reported within Indiana. Similarly, producing districts of Sangamon County may ship to stations along the Cincinnati, Indianapolis, and Western Railroad, as far east as Indianapolis, and including points of delivery within switching limits on connecting lines. A modification affecting the distribution of Jackson and Randolph county coals is as follows: All producers located along the Mobile and Ohio Railroad and short-line connections in Illinois may ship coal to points of delivery on the Mobile and Ohio Railroad within Ten- nessee and Mississippi, as far south as Meridian, Mississippi, including stations within switching limits on connecting railway lines. Consult the District Representative of the U. S. Fuel Administration, 2017 Fisher Building, Chicago, to learn decisions on suggested changes still ponding. Of these changes, the one affecting particularly the coal-gas industry relates to the addition of the Lower Peninsula of Michigan to Zone C 10 RETORT COAL-GAS MANUFACTURE by F. K. Ovitz 1 of the U. S. Bureau of Mines. Mr. Ovitz's work had to do almost exclusively with the manufacture of coal gas from Illinois coals and mixtures of these with other coals. Since the publication of his results, much creditable work has been done by individual companies on the use of Illinois coals in water-gas generators. A separate paper by the authors of this report has been prepared, dealing with that work. Fig. 2. — Bituminous coal zone D, established by the U. S. Fuel and the U. S. Railroad Administrations, April 1, 1918. Includes low-sulphur coal areas in southwestern Indiana. All producing districts of Indiana, shown in black, are restricted in their shipments of coal to markets within or along the heavy boundary line. Consult the District Representative of the U. S. Fuel Administration, 2017 Fisher Building, Chicago, to learn decisions on a number of suggested changes still pending at the time this was printed. This report is the result of an inspection made by W. A. Dunkley, gas engineer of the Illinois Geological Survey, and W. W. Odell, gas engineer of the U. S. Bureau of Mines, working ^vitz, F. K., Coking of Illinois coals, U. S. Bureau of Mines Bull. 138, 1917. — ., Carbonization of Illinois coals in inclined gas retorts: 111. State Geol. Survey, Cooperative Series Bull. 20, 1918. PROBLEMS 11 under the cooperative agreement 2 , in order to determine and re- port at once the experiences of various coal-gas manufacturers with central district coals. The differences in present practice form the basis of a program of further experimentation. PROBLEMS IN THE USE OF CENTRAL DISTRICT COALS IN COAL-GAS MANUFACTURE The operator who has been accustomed to use eastern gas coals and whose plant and operating conditions are laid out es- pecially for these coals is confronted by new problems when the use of central district coals is contemplated. These problems in- clude relative prices and availability of coal supplies, plant capac- ity, labor supply, disposal of coke, purification of the gas, and changes in operating methods. These problems will be discussed separately. 1. Price and Availability of Coals The prices of both eastern and central district gas coals are continually changing. Owing, however, to the considerably longer haul in the former case, there is usually about $2.00 per ton mar- gin between the delivered price of eastern and of central district coals, in favor of the latter. For example, some plants in Illinois report that eastern coals are now costing them about $6.00 per ton and central district coals from the southern Illinois fields, about $4.00 per ton. A difference in price at least equal to this seems likely to be maintained for plants in Illinois and the states to the west. The length of haul from the southern Illinois mines to gas plants in the northern part of the State varies from 250 to 350 miles. On the other hand, the rail haul from the eastern gas-coal fields to the same region averages probably at least twice as long and in at least one case is 720 miles. Taking into consideration the immense freight traffic for other purposes on the east and west lines, especially through the Pittsburgh district, it seems reasonable to expect that the supply of central district coals to local plants would be more certain during freight congestion than would the supply of eastern coals. Since the yearly gas-coal re- quirement of Zone C alone is nearly 2,000,000 tons, an extensive substitution of central district coals for eastern coals would re- lease many cars on the east and west roads for other purposes. 2 An extensive investigation of coal and coal mining has been in progress since 1911 under a cooperative agreement between the U. S. Bureau of Mines, the Illinois State Geolog- ical Survey and the Engineering Experiment Station of the University of Illinois. 12 RETORT COAL-GAS MANUFACTURE 2. Plant Capacity The experiences of those who have used central district coals show that under usual operating conditions, these coals do not yield more than 80 per cent of the amount of gas yielded by an equal weight of good eastern gas coal. The question of plant capacity is therefore one of first importance. If, as is the case at some plants, hardly enough generating apparatus is provided to meet the demand for gas when the highest yields are obtained from eastern coals, then an immediate change to central district coals is impracticable. On the other hand, if a plant has at least 20 per cent spare capacity, this obstacle of decreased capacity is overcome. At many plants where there is a rated surplus ca- pacity, the spare benches are down for repairs and may not be repaired until actually needed for use. In many cases if this sur- plus capacity could be quickly made available there would be no obstacle to the use of central district coals until other benches were let down for repairs. In some plants it was observed that all the coal-gas appar- atus is worked constantly to maximum capacity, and the addi- tional gas required is supplied by water-gas apparatus. In such cases the substitution of central district for eastern coals in the coal-gas plant would necessitate the making of more water gas. The question would have to be decided whether the saving in cost of gas manufacture by the use of central district coals would be offset by the additional cost of making the extra volume of water gas needed, since the cost of water-gas manufacture is usually higher than coal gas. In such cases, if ample water-gas apparatus is available, the use of central district coals as generator fuel might permit a substantial saving in this part of the plant. Under favorable conditions, therefore, the use of central district coals throughout the plant might be found quite profitable. This leaves out of account the desirability, especially at the present time, of conserving the transportation facilities of the country, which should be seriously considered by every gas man. Several plants were visited in which the use of eastern gas coals is not absolutely necessary but is continued either because no financial advantage is seen from making a change, or because the troubles anticipated from the use of central district coals are magnified. Where the total capacity of the plant would permit the use of central district coals, alone or in mixtures, this matter should have the earnest consideration of the manager, especially since their use may become necessary in a few months on account of freight congestion. PROBLEMS 13 Fig. 3. — Bituminous coal zone E, established by the U. S. Fuel and the U. S. Railroad Administration, April 1, 1918, and corrected to July 1, 1918. Includes low-sulphur coal in western Kentucky. Producing- districts in western Kentucky, shown in black, arc restricted in their ship- ments of coal to markets within or along the heavy boundary line. Modifications of the original zoning made prior to July 1, 1918, have been incorporated in the map. Later modifications affecting the gas-coal markets are as follows: Producers in the western Kentucky districts may in addition distribute their coal (1) along the Louisville, Cincinnati and Lexington Division of the Louisville and Nashville Rail- way between Louisville and Newport, Kentucky, inclusive, and (2) in Cincinnati, Ohio, and points of delivery located within the Cincinnati switching district. Producers in this district may not ship coal without permit into those parts of Illinois, Wisconsin, and Indiana, included originally in zone E as shown by the heavy boundary line. A provision is made, however, which should be noted by the coal-gas manufacturer: Any western Kentucky producer may ship coal of special quality for special uses to delivery points within the prohibited territory under permit which may be obtained from the Fuel Admin- istration on application of the consumer. 14 RETORT COAL-GAS MANUFACTURE 3. Operating Labor An occasional plant was inspected in which there is appar- ently ample generating capacity in good condition to handle cen- tral district coals, but the management is not using them because of the difficulty of securing the additional retort house labor to operate the necessary additional equipment. In these cases it is impossible to judge from casual inspection whether the labor situation is really as serious as reported, or whether the policy of the particular company in dealing with its employees is re- sponsible for the difficulty. In one plant visited the labor short- age is so serious that in an effort to maintain the gas supply without starting another bench, heavy charges are made and pulled so "green" that the gas obtained is not more than 80 per cent of the yield which could be reasonably expected from the eastern coal in use. It is evident that the money being lost would far more than offset the readjustment of wage which might be necessary to put the plant on an efficient operating basis. 4. Disposal of Coke Nearly all the gas operators interviewed stated that the cen- tral district coals produce coke which is inferior to that obtained from the best eastern coals; yet it is quite generally agreed that they can sell at the present time all the coke which they can pro- duce from either kind of coal. Some plants could dispose of sev- eral times their present production from central district coal at a profit. With the return to normal conditions of demand and supply, the quality and yield of coke from central district coals will be of renewed importance; and therefore a study of the conditions affecting these will be made as soon as possible. In the use of these cokes as water-gas generator fuel the experiences of various operators differ. Some operators have much trouble with the clinker formed from these cokes, while others handle the clinkers without particular difficulty. Further study of clinker formation is needed and will be made in the near future. Operators who are using central district coals as gener- ator fuel in water-gas machines usually report less clinker diffi- culty than where the coke made from the same coals is used. This indicates that the operating conditions in the generator are of at least as great importance as the composition of the fuel and ash. PROBLEMS 15 5. Purification Many operators beginning the use of central district coals anticipate that a much larger amount of sulphur will be yielded in the gas from these coals than from eastern coals. One oper- ator who has never used central district coals states that there is not enough purifying material in the United States to purify the gas from one carload of Illinois coal ! While it is true that many coals of this district can not be used under present conditions because of their high-sulphur content, yet there are many coals produced in the central district which are nearly as low in sul- phur content as eastern coals. A subsequent publication will pre- sent a description of the low-sulphur coals mined in the central district. Few companies who have used these coals report any serious difficulty from excess sulphur in the gas. Where sulphur has caused trouble, it is usually impossible to learn definitely whether the sulphur in the gas has been excessive or whether the purifying material in use at that time was inefficient. In most of the plants inspected there are no facilities for making quanti- tative tests of sulphur in the gas. The more general use of the Tutweiler hydrogen sulphide apparatus among the various gas companies would seem to be advantageous. In most of the plants visited, the purifying capacity is ample to purify the gas pro- duced from any of the better coals of this district. 6. Operating Methods with Central District Coals So far as can be learned from various operators, the use of central district coals in retort gas practice at present is in gen- eral no different than the use of eastern coals. Practice varies considerably in different plants, but these variations are due to personal views of different operators as to what heats, coking times, weights of charge, etc., give the best results in their par- ticular cases, rather than to any generally recognized "best way" of using these coals. With the considerable differences in practice which exist, there are no very marked variations in the results obtained. In carbonizing coals in retort practice several variable con- ditions influence the quantity and quality of the products. Among these, the conditions which are most easily changed and most likely to be varied by different operators are: retort tempera- ture, length of coking time, size of charge, and size of coal. One operator favors a certain combination of these conditions for a given coal, while another operator selects a different combination. The results obtained may be almost identical. 16 RETORT COAL-GAS MANUFACTURE Some operators favor high retort temperature for central district coals, claiming that the rate of heat penetration into the charge is slower than with eastern coals, and that high tempera- ture is necessary to obtain complete fusion of the coal and conse- quent strong coke structure. They point to the granular structure of the coke from some of these coals as evidence of incomplete coking due to insufficient temperature. On the other hand, other operators say that the heat penetration is more rapid with these coals and that a poor, weak, fingery coke structure is more liable to result from over-coking the charge, and consequently they favor lower retort temperatures for these coals. Long coking periods are preferred to short periods by some operators. They often claim that a higher yield of good quality gas and a higher yield of ammonia are obtained with a long period of coking at a moderate temperature than with a short coking period at a high temperature. On the other hand, some operators say that a long coking period over-cokes the charge, weakens the structure of the coke, and makes it more liable to break into small fingery pieces. Evidently the same results are frequently attributed to long coking as to high temperatures. There is usually no way of deter- mining what the temperature of a retort actually is. Gas plants are not generally equipped with pyrometers, and the degree of temperature carried is merely a matter of judgment, into which the personal opinion enters very largely. The study of these vari- ables would give much-needed information, and it is hoped that such a study may be undertaken soon. There is no uniformity in the weight of coal charge in differ- ent plants having retorts of the same size. Usually the charges are as large as can be properly coked in the chosen coking period and vary from 325 to 400 pounds. The weight of charge seems to be the means of heat control in many plants. If the retort tem- peratures drops, the weight of charge is decreased, or vice versa. The weight of charge is also varied to diminish standpipe stop- page and to prevent naphthalene deposits. So far as could be learned no difference in the size of charge is required with cen- tral district coals and with eastern gas coals. Size of coal is another varying condition about which great difference of opinion is expressed. Fine crushing of the coal would undoubtedly result in a more intimate mixture of all the components of the coal and result in a more uniform and stronger coke. However, there is considerable difference of opinion among RESULTS 17 gas men as to the feasibility of crushing coal. Only a very few plants are equipped with crushers. Some operators claim that whereas the quality of coke from crushed coal would be better, the heat penetration into crushed central district coal is so slow that the usual yield of gas is not obtained from the coal during the short coking period which the retort gas maker can allow. However, at least one inclined-retort plant was inspected which is coking crushed coal and obtaining, not only a very good coke from southern Illinois coal, but a yield of gas greater than is produced by most plants using uncrushed coal. From appear- ances, the coal is thoroughly coked in 6 hours. Some operators expressed novel opinions and theories upon the coking of various coals, and though these ideas have no place in this report, they suggested problems for further study. RESULTS REPORTED FROM CENTRAL DISTRICT COALS Several of the coal-gas plants in Illinois are using eastern gas coals this summer. Some of these plants used central district coals during the past winter or at some previous time, but the results of their experiences with these coals are available chiefly as more or less definite impressions. The following are typical re- sults reported where definite figures are available ; unfortunately none for Indiana or western Kentucky is included. These results are in fair agreement with those reported by Mr. Ovitz and indicate that no radical developments in the use of these coals in ordinary retort practice have arisen recently. The central district coals now in use are from only a few mines, and it seems likely that much valuable information can be obtained by the testing of other coals and mixtures of coals from this dis- trict. A more intimate knowledge of such conditions as tempera- ture, coking time, size of coal, rate of heat penetration, and other variables is also needed. This information can come only by ex- periment. Some gas men believe that the most successful use of central district coals will come through new by-product oven or low-tem- perature processes, rather than by any modification of operating conditions in the present equipment. Certain investigators are working on such processes, and some attractive claims are made for them, but as yet no commercial plants built to use these pro- cesses are in regular operation with central district coals. 18 RETORT COAL-GAS MANUFACTURE id O as S ^5 <£> T3 CD 3 o ^ u > -S bD o O ^C