US1894691A - Destructive distillation of carbonaceous material - Google Patents

Description

Jan. 17, 1933.

L. p. KARRIcK DESTRUCTIVE DI STILLATION OF CARBQNACEQUS IATER IAL Filed Nov. 16, 1925 s Sheets-Sheet 1 INVENTOR ATTORNEYS.

mmmwsms Jan. 17, 1933. c. KARRICK DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIAL 3 Sheets-Sheet 2 Filed NOV. 16, 1925 C M M 0% m8 +0 M m w. A n a W 5a m% m 9% 0 4 a w .w M m ATTORNEYS.

Jan. 17, 'c, K RRICK 1,894,691

DESTRUCTIVE DISTILLATION 0 CARBONACEOUS MATERIAL Filed Nov. 16, 1925 3 Sheets-Sheet 5 INVENTOR ZWAW W BY v ATIORNEYi l atent ed 17, 1933 l U N ITED STATES PATENT OFFICE LEWIS CASS KARRICK, OF SALT LAKE CITY, UTAH DESTB'UO'IIVE DISTILLATIOK OF CABBONACEOUS MATERIAL Application, filed November 16, 1925. Serial No. 89,800.

This invention relates to distillation of many kinds of coal may possess some of the carbonaceous material such as oil shales coals physical and chemical properties of the genlignites, cannel coals, wood and oil sands, and erall used activated carbons of commerce. partial gasification of fixed carbon. It is W ere coals like Utah coals are subjected well known that variations in the time and to distillation the plastic or compressible 55 the temperature of distillation will produce nature of the heated coal may be utilized to marked differences in the yield and quality press the mass into large, dense, solid masses of the products from such materials. Acor lumps of fuel suited to the commercial decording-to the present invention distillation mand. This has been effected by making the is effected at temperatures very low comcolumn of distilling material in the retort of pared with those ordinarily emp oyed in gas such aheight thatits weight accomplished the plants and coke oven firactlce. Not only does continuous com ression of that portion of the temperature app ied alter the yield and the mass which is in the hot lastic state. In character of the volatile products but it also this manner it has been foun possible to supaffects the character of the carbon residue so ply pressure which has resulted in producing that, by the present invention, carbon which a product having an apparent s ecific gravis easily kindled may be produced from coal ity of 0.85, as contrasted with the usual ap- -and constitutes a product which is markedly parent specific gravity of coke, to wit: 0.55. difierent from the nearly graphitic product The present inventlon'is especially useful of coke ovens or gas plants which is difiicult when the coal is uniformly sized,thus avoidto burn. This carbon is in condition to yield ing the obstruction to gas flow which would readily to partial gasification in the process. come from the distilling of material consist- The invention will be particularly deing of commingled large and small lumps or scribed in connection with the treatment of particles.

coal, but it is to be understood that it is The residual coke maybe quenched at the 75 applicable to the treatment of other carbonbottom of the retort by saturated steam so aceous materials such as those mentioned as to extract heat from it and cool it, thereby above. accomplishing continuous dry-quenchin Coal, preferably in the form of lumps, is This roduces su erheated steam which aimfs heated in a retort and the source of heat is the distillation o the overlying material and partly superheated steam flowing counterreacts with the coke to produce water-gas current to the coal but in addition a-portion and some ammonia.

of the heat is transmitted through the walls The steam or gas used for quenchin forms of the retort from an external source. Proa barrier preventing the superheate steam vision is also made for increasing the gas entering hlgh up in the retort from passing yield at times by gasifying a portion or subdownward and condensing in the lower bin. stantially all of the fixed carbonb the efiects Incondensable gas from the condensers is of a second-supply of superheate steam and also preferably introduced continuously into when occasion requires, also by a supply of the top charging bin so that its downward hot products of combustion. p flow toward the vapor exit prevents steam The invention herein disclosed as applied or oil vapors from passing into the charging to bituminous coal yields a dense carbon resib1n and condensing, with consequent loss of due which is very easily ignited and which heat and wcttmg f the charge. The gas burns readily without smoke. When the for the charglng binis prefera 1y preheated process is applied to anthracite coal the reso as to dry and preheat the raw material in sidual product has greatly improved kindling the'bin.

and burning properties, even though the vola- The easily kindled residual material is tiles distilled ofl" are a rclativel small proespecially adapted to serve in the manufacportion of the coal. The resi ual carbonture of water gas, as it reacts very rapidly 10o aceous products produced by the process from and easily with steam. This material may also be used for other purposes since it is well adapted to adsorb salts from solution, hydrocarbon vapors, or odoriferous vapors, thus rendering easy the preparation of a fuel having any desired burning, light-giving and odor-producing qualities.

If desired. a part or all of the internal heating of the retort may be effected by using the sensible heat of products of combustion resulting from burning some of the incondensable gas from the retort. It has been found that where the products of combustion of gas. instead of the products of combustion of coal. were used for this purpose, the gases of distillation were less diluted by nitrogen and carbon dioxide and the efiluent distilled gases were. of greater calorific value than when the products of the combustion of coal were used for heating.

Under one condition of operation I found that the original lumps of coal passed through the retort substantially without disintegration. It was found possible to press the coal into large aggregates under conditions which permitted the lumps to agglomcrate by their cohesive and plastic properties when hot. This was effected by using slower rates of feed and a higher distilling zone in the retort. The resulting smokeless fuel formed into lumps of the shape and diameter of the inside of the base of the retort, namely seven inches diameter and varying in length from six to eighteen inches.

Each large lump was almost homogeneous in texture and structure throughout its diameter although it was composed of an aggregate material passing a one-inch screen and retained on a three-fourths inch screen.

The process may be applied to coking coals which cake into large masses and thus, unless properly handled, tend to block the proper flow of steam and vapors. To treat such coals they are mixed with a suitable proportion of residual fuel from a previous run, with the result that no blocking takes place as they feed through the retort.

The superheated steam is supplied at a temperature high enough to distill the condensable volatiles and residual volatiles and gasify an appreciable amount of the fixed carbon. I have used temperatures varying from 950 F. to 1,725 F. depending on the product and conditions desired. At the lowest temperature named the distillate was almost exclusively coal 'resins. At the highest temperature named the thermal efficiency was greatly improved, a very large yield of oil and water-gas was obtained, and the smokeless fuel was superior in hardness, texture. and color.

In the accompanying drawings is shown, largely diagrammatically, a commercial plant for carrying out the process. wherein Figure 1 is a vertical cross section through a series of retorts arranged along a bench, taken along the line ?26 of Figure 3.

Figure 2 is a Vertical cross section between two retorts, with parts broken away, along the line a-a of Figure l.

Figure 3 is a horizontal section along the line 0-0 of Figure 1.

Figure 4 is a horizontal section along the line dd of Figure 1.

The coal or oil shale is charged into the supply bins 1 which are closed at the center of their hopper-bottoms 2 by suitable valves 3 so that auxiliary feeding bins 4 may be conveniently charged. Each auxiliary bin 4 has a hopper bottom 5 which opens into a retort shaft 6 at its bottom. The retort shaft is herein shown as tall and narrow and is, therefore, adapted to contain a long column of carbonaceous material, which is supported at the bottom by a pair of-rotata'ble shafts 8 having overlapping arms 9 which rotate out wardly to feed down the residual coal or oil shale after it has been distilled. The valves 3 are normally closed, with the result that the vapors rising from the charge in the shaft 6 pass through vapor off-takes which will be later described. The capacity of the auxiliary bins 4 is such that at no time does the top of the charge in the bin descend below the level of the vapor off-take and thus the shaft is completely filled with the charge at all times. The rate of downward movement of the charge is controlled entirely by the discharge mechanism or rotatable shafts 8. In addition to the rotatable shafts 8 and their arms 9 there are rovided pivoted rock-arms 11 at each side of the retort under the upper walls of the residual receiving bin 13, each rockarm being provided with a counterweight 12 so that the rock-arms may swing and allow the residual coal, etc. to feed downward by the rotation of the shafts 8. The receiving bins 13 are provided with hopper bottoms 14 and suitable closures 15 operated by rotating shafts 16 provided with cranks 17 connected by links 18 to the closure 15, and operated by external handles 7.

When the charge is feeding downwardly through the retort 6 superheated steam is admitted through ports 20 into the shaft to heat the charge to distill off the volatiles.

.These ports, in the form of retorts herein illustrated, are about half way up the height of the retort. The steam is derived from suitable sources, not shown, preferably engine exhaust steam somewhat above atmospheric pressure where such is available, or steam at lower pressure may be used so that the retort may be operated at a low pressure, even below atmospheric. Where waste steam is available it furnishes a very inexpensive and otherwise desirable heat carrier to transfer heat into the retort.

Steam as above described feeds into a steam pipe 21 forming part of the superheater 22.

The steam passes from the pige 21 through a horizontal passage 23 exten ing the entire length of a retort. This connects with a short vertical assage 24 and the steam passes throu h t 1is and thence back through ahorizontzil passage 25 similar to the horizontal passage 23 and through another short vertical passage 24 and similarly through other horizontal passages 25 and vertical passages 24 until it reaches the to horizontal passage 26 of the superheater lie-latter passage is rovided with a number of ports 20 opening into the retort as described above. For heating the steam in its travel through the passages 23, 24, 25 and 26 there is provided a group of parallel vertical heating flues 30 situated outside the passages and between the superheater 22, above described and an identical superheater for the adjacent retort. This superheater has similar (ports 20 leading into a retort 6 which may be i entical with the first retort,

The heated gases passing downward through the vertical flues 30 are produced by the burning of preheated fuel as in a fluelike combustion chamber 28. he reheated fuel gas enters the chamber 28 by t e port 27 at the end of the superheater structure, and the preheated air enters the chamber 28 by a duct 29 extending from the adjacent preheater, as hereinafter described. The preheated air and preheated gas burn in the com bustion chamber 28 above the top of the vertical fiues 30 so that the hot gases, which ma be still burning, pass downwardly throw the vertical flues 30. Immediately above t 1e flues 30 is the floor 31 of the combustion chamber 28 which is perforated by ports 32 so as to communicate with the vertical fiues 30.

When the hot gases pass to the bottom of the lines 30 they turn in short horizontal flucs 33 outwardly in opposite directions toward the adjacent retorts and then pass upward on the opposite sides of the superheaters and through the fines 34 of which one wall forms part of the walls of the adjacent retorts. Then they pass through ports 35 in the floor 31 and enter the vertical parallel flues 36 of which one wall forms part of the upper walls of the retor'ts and rises substantially to the to s of the rctorts. At the upper end of the nos 36 the gases turn horizontally through short flues 37 and are then directed downward through a chamber 38 which contains an air or gas preheater 39 (see Figure 1). The prehcatcrs are alternately air and gas preheatcrs, i. c., each preheater consists of two parallel and independent piping systems one of which discharges its preheated product directly into the combustion chamber 28 beneath it and the other of which discharges its preheated product into the coinbustion chamber 28 to the right of that beneath it. Thus each combustion chamber 28 is supplied with preheated air from one preheater and reheated gas from another preheater. ThlS arrangement is adopted to avoid having side by side in a'preheater a pipe carrying air and a pi e carrying fuel gas, for obvious reasons. ir or gas enters its respective preheater by pipes 40, which extend the Ian th of the retort horizontally through the ciambcr 38 of the preheater. Each pipe 40 delivers the air or gas through a short upward section 41, and then through a return section 42, back to above the point of entrance of the heater, and similarly the a r or gas passes back and forth through pipes 41 and 42 until it reaches the top of the space 38.

The heated air or gas delivered by the last pipe 42 enters a vertical passage 43 which carries the air or gas down to the combustion chamber 28, delivering its reheated gaseous material either to the cham )er 28 immediately beneath the preheater or to the chamber 28 beneath the adjacent preheater, as above described.

The products of combustion after passing downwardly over the preheater pipes 42 reach the bottom of the chamber 38 and'are carried ofi horizontally through the duct 44 to a stack, not shown.

From the charge in the retort, heated by the superheated steam entering through the.

ports 20, most of the volatile ingredients distill. These volatile ingredients rise through the voids in the retort charges to the tops of the retorts and pass off through va or offtakes 46 provided with valves 49 which lead to a va or main 50. As shown in Figure 2 the auxiliary bins 4 are separated from each other, being set at intervals along the lengths .of the retorts, thus providing clear spaces in which rise the vapor off-takes 46 from the tops of the retorts.

If not enough fuel gas is produced from coal by the procedure above described in which superheated steam is introduced at the ports 20 a modified )rocedurc may bev adopted in which super cated steam is introduced at lower ports 45 (of which only a few are illustrator) to evolve water-gas by reaction with the heated carbon residue.

This additional supply of superheated steam enables the gas production to promptly meet peak loads. To supply superheated steam through the ports 45 there is provided a well-insulated steam duct 51 leading from J gas.

In cirder to introduce the hot products of combustion from the chamber 28 into the charge, there-are provided ports 53, intermediate the ports 45 and the ports 20, en-

ing into the retort and connected b s ort flues 54 with the vertical combustion ues 30. All the ports 20, 45, and 53 are under the control of the retort operator, who may control the fiowthrough them by suitably placed bricks which serve as adjustable closures to alter the flow of gas or steam, and are not shown.

In order to control the character of the solid residue from the distillation of coal so 3 that it may be suitable for use or for storage as may be desired, there are provided valved pipes which may be used to 1ntroduce steam or gas into the receiving b ns 13 for the urpose of quenching the residual coal 9 disc arged from the retort.

In runs of some kinds of coal with a cyllndrical retort such as described above I have successfully used both steam and gas for dryquenchin the residual coal to a temperature 23 at which it would not take fire on exposure to air. It was found that this did not so lower the temperature within the retort by reason of the ascending steam or gas as to interfere with the proper functioning of the retort.

3 A form of condensing apparatus which has proved satisfactory is shown diagrammatically at the right of the retorts in Figure 1 on a greatly reduced scale in proportion to the other parts of the drawings. The

' vapors coming through the vapor mains 50 are carried to the bottom of a larger aircooled tower 56 which may be of iron, provided with a valved bottom outlet 57. From the top of the tower 56 the uncondensed vapors and gases enter a second similar tower and so on for any desired number of towers. Finally from the last tower 58 the still uncondensed vapors and gases are carried to a water-cooled worm 59 which delivers them i to a closed separating vessel 60. Here the water settles to the bottom and may be drawn off through a valved drain-61. On the water usually floats some light oil which may be drawn off by an upper valved drain 62. From the top of the separating vessel 60 leads a valved gas pipe 63, which may be connected to the gas pipe 55 for quenching the residues, and may also be connected to valved gas pipes 64, which enter the feeding bins 4 and serve to keep a steady flow down into the retorts, thus preheating the coal or other material fed to the retorts and maintaining a gas barrier which excludes from the feeding bins 4 the steam which is heating the contents of the retorts. This gas may he preheated by any suitable means, not shown.

It will be noted that the retort structure shown has straight wails and therefore there is no need to use special forms of brick in building it or to use any materials which are gpecially adapted for peculiar variations of orm.

The retort itself should be constructed of material especially adapted to the work going on in the different parts, the upper part preferably being made of metal, such as good quality cast iron. The high temperature parts of the retort and auxiliaries may be found to give longer and more economical service if constructed of silica or carborundum brick. The lower part of the retort next the superheaters is preferably constructed of some material having better heat conducting properties than nonmetallic refractories, for example chrome iron or other suitable metallic material.

It will be noted that the coal or other material treated according to the present process is fed into a relatively cool section of the retort and gradually progresses downward through successively hotter zones until it reaches the level of an admission port where it is exposed to the greatest heat. The coal then feeds through a section of the retort of substantial length where it is maintained substantially at the temperature of greatest heat for a relatively long period of time. In this section considerable exothermic heat is evolved when Utah or other high-oxygen coals are treated, thus augmenting the supply of heat and meeting the requirements of heat for devolatilizing the coal. In cooling the residual material by steam at very large part of the residual heat is recovered. The rising steam may react to form Water-gas and absorb a large amount of heat, but this heat is made up by heat transmitted from the walls. It is found that the water-gas reaction takes place efficiently under the conditions named even at the relatively low temperature of 1,275 F.

Having thus described certain embodiments of my invention, what I claim is:

1. The process of treating dust free lumps of coal to produce a useful solid fuel which comprises, heating the coal in the absence of an appreciable amount of air by a large supply of superheated steam at a temperature sufiicient to cause heat decomposition of the coal, and providing additional internal heat by supplying and burning mixed fuel gas and air within the retort.

2. The process of treating coal to produce therefrom volatile and coke and gasify part of the coke which comprises, heating a body of coal in a chamber internally by superheated steam counter-current inside said chamber and also heating the coal externally ent points spaced therealong, the steam at one stage being of lower temperature than the steam in the other stages and being passed throu h the hot solid residue.

3. %he process :of treating coal to roduce therefrom volatile and coke and gasify part of the coke which comprises, heating a body of-coal in a chamber internally by superheated steam countercurrent inside said chamber and also heating the coal externally through the walls of the chamber sufiiciently to cause heat decomposition of the coal, said superheated steam being derived from different sources and delivered to the coal body simultaneously at three difierent points spaced therealong, the steam at one stage being of lower temperature than the steam in the other stages and being passed .through the hot solid residue, and gasifying more of the coke by admitting superheated steam in variable uantities at a point between the places where t e other steam is admitted.

4. The process of treating coal to produce therefrom volatile and coke and gasify part.

of the coke which comprises, heating a body of coal in a chamber internally by superheated steam countercurrent inside said chamber and also heating the coal externally through the walls of the chamber sufiiciently to cause heat decom osition of the coal, said superheated steam eing delivered to the coal body simultaneously at three different points spaced therealong, the steam at one stage being of sup l y of superheated steam at a temperature su cient to cause heat decomposition of the coal, providing additional internal heat by supplying and burning mixed fuel as and air within the retort, collecting the solid products separately from the fluid products, partially condensing the fluid products so as to leave a residue of gases, and conducting a portion of said residue of gases into contact with the lumps of coal in said chamber before delivering the same into the retort.

In testimony whereof, I have afiixed my signature to this specification.

LEWIS CASS KARRICK.

' lower temperature than the steam in the I other stages and being passed through the hot solid residue, and supplying steam to the coke residue to provide further heat while controlling the yield and quality of thefuel of an appreciable amount of air by a largegas produced from the coal.

5. The proces of treating coal toroduce therefrom volatile and coke and gasify part of the coke which comprises, heating a body of coal in a chamber internally by superheated steam countercurrent inside said chamher and also heating the coal externally through the walls of'the chamber sufiiciently to cause heat decomposition of the coal, said ilggerheated steam being delivered to the coal y spaced therealong, the steam at one stage be; ing of lower temperature than the steam in the other stages and being passed through the hot solid residue, gasifying more of the coke by admitting superheated steam in varied ailiantities at a point between the places where e other steam is admitted, and supkplyinghot products of combustion to the co e residue to provide further heat while controlli the yield and quality of the fuel gas produce from the coal.

6. The substantially continuous process of treating dust free lum of coal to produce fuels including a use solid fuel and which comprises continuously feeding the coal from a closed chamber into a retort, heating the coal in the retortin the absence simultaneously at three different points

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