US1767778A - Process for carbonizing coal - Google Patents

Description

JuneI 24, 1930. w. E. TRENT PROCESS FOR CARBONIZING COAL Filed Feb. 27, 1925 i 4 H 7- l@ E E i m m .w ,C E F y@ MEW M E AOp A.

Patented June 24, 1930 UNITED STATES WALTER EDWIN TREN'I, 0F NEW' YORK, N. Y., ASSIG-NOR TO TRENT PROCESS CORPO- RATION, OF NEW YORK, N. Y., A CORPORATION F DELAWARE PRocEss Fon CARBONIZING coAL Application med February 27, 1925. serian No. 12,129.

The invention relates to a process for carbonizing coal and coal and oil mixtures to produce carbonized or coked products of substantially the same dimensions as the ygreen preformed fuel masses.

' product will be free of substantial swelling or shrinkage, and, therefore, of dimensions substantially the same as the dimensions of the original green mass from which the car-l bonized fuel is produced.

My invention, therefore, broadly comprehends a two-'stage treatment in the carbonization of coals, in which the coal in the first 'stage is partially carbonized under a low temperature in the presence of a limited amount of oxygen and in the secondstage ,is 'heated to a high temperature in an atmosphere substantially free of oxygen to 4form the carbonized products herein referred to.

ln the accompanying draWings,-

Figure 1 is a View of an apparatus capable of carrying out the first-stage treatment; and

2 is a view of the apparatus used in the second-stage treatment of the coal.

Fig. 3 is a View of a slightly modiied form of pan.

'Referring noW more particularly to the drawings, wherein like reference characters indicate corresponding parts, the numeral 1 designates the carbonizing furnace used for the purpose of heating the material to a low temperature in the presence of oxygen. This furnace has a sprocket 2 at one end and is also provided with gas outlet pipes.

3 leading to a header 4. A sprocket 5 is disposed outside of the furnace and this sprocket together with the sprocket 2 receives the endless conveyor 6 l carrying a series of pans 7 each havin a false bottom 8, providing a receiver 9 for heat storage elements to be later described. The pans move Vthrough openings 10a in one Wall of the chamber 1, Whichv openings are suficiently large. to permit the introduction of a limited quantity of oxygen to the chamber 1 during the distillation and heat treatment of the materials therein.

The pans as they reach the point are adapted to each receive preformed masses a of coal and oil of a plastic consistency or masses ofy coal With any suitable binder. These masses may be shaped in a molding machine or other suitable type of apparatus. They are placed in the pan 7 as the pans enter the retort 1. The fuel masses are heated during passage through the retort by heat imparted thereto by heat storage elements 10. These elements are composed of cast iron or' other material capable of absorbing heat and are heated in a furnace exteriorly of the oven 1. They are inserted vin the pockets 9 formed in each pan'at the point and travel With the pans through the carbonizing zone 1, applying heat to the preformed masses` in the pans duringthis travel. As shown in Fig. 3, the pans need not have the false bottom 8. 1n this operation the heat storing elements 10 rest on the bottoms of the pans and the preformed masses seat directly on these elements.

When a pan reaches the point m the cool heat storing member 10 is removed and a heated element substituted in its place. One or more of the preformed masses a are then placed in the pan. storing element passes on through the carbonizing retort undergoing a low temperature carbonizing treatment therein in the presenceY of oxygen entering the retort through the openings 10a. lln this operation the `heat storing elements 10 are preferably heated to a temperature sucient to impart to the preformed-fuel masses a temperature of from 450 to 575 F. The speed ofthe conveyor through the retort. is regulated so'that it will require from 45 minutes to 1 hour 30 minutes for apan with its material to travel through the retort to the 'llhe pan with its heat asf the opening of the valve 20.

sprocket 2. rlhis temperature and time of treatment is followed when using a non-coking coal. If a highly coking coal is used, substantially the same temperatures are employed but the time of treatment must be longer. This time of treatment Will vary from one and one-half hours to four hours. The coal thus treated Will be hardened or carbonized around its surface but Will not be coked. vrl`he fuel masses may be said to be no more than case-hardened by this treatmerit, and of course, a substantial quantity of the lighter volatiles is removed.

After treatment in the retort 1 the casehardened fuel masses are dropped into the trough 11 and discharged through the outlet line 12 on to a conveyor 13, the empty receivers passing on back to the point Where new heat storage elements are inserted and Where fresh charges of fuel are placed in the receivers.

lThe foregoing treatment constitutes the the first-stage treatment of the fuel.

r1`he case-hardened masses depositing on the belt 13 are then led by this belt to a suitable retort 14 Where said masses are subjected to a considerably higher temperature to undergo a higher degree carbonization therein. Various forms of retorts can be used for this purpose but for the sake of illustrating the invention l have disclosed a vertical shale retort. rllhis retort has an outer insulated Wall 15 and an inner spaced Wall 1o. rlhe lovver part of the Wall 16 is lined With hre clay 17 While the upper portion thereof consists merely of steel or iron, there being a space 18 between the Walls. rfhe carbonized fuel masses carried by the belt 13 are discharged into the hopper 19 at the top of the retort and permitted to enter the retort by These masses fill the retort which has its lower end closed by a belt 21 movable over pulleys 22. Gas burners 23 enter the space 18 between the Walls of the retort, producing a dame that is projected against the Wall 16 of the retort, raising the temperature thereof to the desired degree. l preferably heat the carboni'zed vmasses in the retort at a temperature of from 1100 to 1200o F. This maximum temperature is/attaine'd near the lower part of the retort. Little or no air is present in the interior of the retort containing the preformed fuel masses 24 Which are undergoing heat treatment therein, and l have discovered that when these masses are treated in this retort under 'the temperatures mentioned in the absence of air, that the casehardened masses will carbonize or coke Without swelling. That is to say, the carbonized fuel thus produced'is in 'the form of preformed masses of the .saine dimensions as the dimensions of the green fuel charges a introduced to the preheating or case-hardening retort 1. There is no swelling nor Warme prevent over-heating of the brick Wall 1'? of the Wall 16 and tol distribute heat throughout the retort.

The bottom Walls of the retort are slightly cut away as indicated by the reference character 27 and as the fuel masses reach the bottom of the retortthe conveyor 21 is moved to carry out of the retort those masses that have been suihciently treated. Such masses are led to a point ofcollectioii.

ln treating the case-hardened masses in the final retort l preferably subject such masses to a treatment of from 45 minutes to one and one-half hours, and as before stated, heat the carbonized masses to a temperature of from 1100 to 1200 F. This, l have found, causes a complete carbonization or coking of the fuel charges Without causing these charges to swell or become distorted. 1t will also be observed that this high tem.-

perature treatment should be carried out in an atmosphere in which little or no oxygen is present.

lt is believed from the foregoing that the operation of this process/ isy apparent but it may be briefly repeated as follows:

Fuel masses formed in a molding maehine, press or the like, of any desired contour, are

placed in the pans 7 which also carry the heat absorbing elements 10. These fuel masses a pass through 4the low temperature oven 1 and undergo partial carbonization in the presence of oxygen admitted to said retort through the openings 10% rlhis treatment causes a case-hardening or partial carbonization of the fuel masses. 'fhe'y are discharged from the containers as the containers pass around the sprockets 2, aredeposited Y on the belt 13 and led to the high temperature retort 14. ln this retort 1d a temperature of from 1100 to 1200o F. is maintained' as compared With the comparatively low temperature of from 450 to 575C in the retort 1. Little or no oxygen vis permitted to enter the retort 14 and the coking or carbonizing of the partially carbonized masses entering this retort is carried on in the absence of an oxidizing atmosphere. A. definite time of treatment must be maintained in the lovv temperature retort 1 and also in the high temperature retort 14C. These periods of treatment have heretofore been set forth.

The fuel masses discharging from the retort to an increased temperature in ainal heat- 14 are substantially completely carbonized ing zone to complete carbonlzation thereof and these masses are neither swollen nor has While excludlng air from said zone.

there been any substantial shrinkage as compared with the original fuel masses w. The carbonized product recovered is of dimensions substantially the sameas the dimensions of the green fuel charges from which the product is made. -These fuel charges are carried from the retort 14 by the belt 21 trained around pulleys 22 and deposited in a suitable storage space or container not shown. i

Having thus described the invention, what I claim is:

1. A carbonizing process, ,consisting in applying preformed masses of carbonaceous., material of at least plastic consistency to a receiver, in disposing in heat conductlve relation with said masses heat storage elements,

in moving the fuel masses and heat storage elements through a retort where the fuel masses are heated to a temperature in the presence of air sufficient to partially carbonize the same, in then `transferring the partially carbonized .fuel masses to a second retort, and in subjecting said masses in said retort to a substantiallyv increased temperaturewhile in an atmosphere largely free of p oxygen for such time as t0 completely carbonize the fuclmasses Without'causing diss tortion or shrinkage thereof.

2. A process for carbonizing preformed masses of carbonaceous material of at least plastic consistency, consisting in preliminarily introducing said masses to a heating zone, in there heating the masses to a temperature suilicient to cause only partial carbonization thereof While permitting a free unobstructed entrance of air`to said preliminary heating zone, in introducing the partially carbonized fuel masses to a nal heating zone, in subjecting said masses in said zone to a substantially higher temperature for such time as to completely carbonize the fuel lmasses Without `causing distortion or shrinkage thereof While substantially excluding air from said final heating zone, the initial heat treatment of the fuel masses being characterized by the application of heat to said masses transmitted thereto by heat storage elements containing sutlicient heatto partially carbonize said masses.

'3. A process of carbonizing preformed masses of carbonaceous material of at least plastic consistency consisting in introducing said preformed masses to a preliminar heating zone, in moving said masses throug said zone while positioned adjacent heat storage means havingstorage capacity suiii- Icient to' partially carbonize said masses by the contained heat thereof, in permittingal free admission of air through said zone durlng the carbonizatlon of materials therein,

in subjecting the partially carbonized masses In testimony whereof I affix my signature.

WALTER EDWIN TRENT.

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