US2658061A - Apparatus for the retorting of oil shale and similar materials - Google Patents

Description

Nov. 3, 1953 Filed Se t. 22, 1949 G. TRIPP ETAL 2,658,061

I /0 1! I0 I l0 l2 Hecmng or /2' carrier gas r k 4 V l Q I Retort Heat e q I\.\// 9 on transfer y 9,, v 9

misl zone 75f Agglomerl I j \C 5 collecting v Hot zone spent shale 20 B A INVENTORS ATTO NEY Nov. 3, 1953 Filed Sept. 22, 1949 Fig. 2

J. G. TRIPP ETAL APPARATUS FOR THE RETORTING OF OIL SHALE AND SIMILAR MATERIALS 2 Sheets-Sheet 2 INVENTORS Lewis H. Bra/rel John 6. Tripp George 0. Gould ATTO N EY Patented Nov. 3, 1953 UNITED STATES PATENT OFFICE APPARATUS FOR THE RETORTING OF OIL SHALE AND SIMILAR MATERIALS Application September 22, 1949, Serial No. 117,246

5 Claims.

The invention herein described and claimed may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to an apparatus for recovering oil from oil shales and similar materials. It is particularly directed to an improved apparatus in which the oil is retorted from the oil shale by means of hot gases and the oil removed immediately upon formation with a minimum of destructive pyrolysis because it is carried from the zone of peak temperatures. Whereas this invention has particular utility in the processing of oil shale nevertheless it could be used to release other volatile liquids physically held by solids or even to thermolytically produce liquids from carbonaceous solids.

It is common practice in the art to recover oils from solid oil-bearing materials, particularly to recover shale oil from oil shales. The recovery of the oil from oil-bearing or -producing material may be accomplished by means of external heat alone or by internal heating through contact with hot gases. As to the former, the disadvantages are that there is a large amount of surface required for heat transfer, and excessive temperatures on the heating surfaces are necessary to bring the interior to the requisite range.

A form or apparatus wherein the principle of internal heating is applied, and which form has the advantage of continuity of movement of the material through the carbonization chamber and passage of hot gases up but preferably down through the oil shale undergoing treatment, is that of the Wallace, British Patent No. 473,188.

It is an object of the present invention to provide an apparatus in which the oil shale is preheated, reterted and the released product oil is condensed and caught in a sump.

It is still another object to provide an apparatus for continuous retorting of shale so arranged that the incoming oil shale serves as a cooling medium and condenser for the vaporized oil, and in turn is pre-heated. In this way a sep' arate unit for shale pre-heating and separate heat-exchange unit, such as a tubular condenser, for cooling the retort gases below their dew point are dispensed with, as well as the cost of their operation and maintenance. The heattransfer coefficient in cooling gas is relatively low and a large surface for exchange would be involved in oil recovery system requiring a metal heat transfer unit. An additional advantage for the equipment covered by this application is the 2 fact that no process cooling water would be required to retort shale.

A still further object is to provide an arrangement in a retorting apparatus which makes use of the excellent heat transfer conditions that exist between a stream of gas and a bed of crushed solids.

In our apparatus operation is simplified. In our apparatus investment in equipment is cut down. For only one piece of equipment is needed to perform all three of the functions noted above; and the components of it are not complex.

Other more specific objects and advantages of the invention will be made apparent from the more detailed description hereinafter. Several definitions will first be given to avoid an explanation in the recital of the process. Make-gas is defined as that gas which is generated during the retorting of oil from oil shales but is not purifled. Carrier or heating gas is defined as that gas which is used to carry the heat required to retort oil shale. Retort gas is defined as that gas which leaves the retort. It contains the carrier as, the make-gas, vaporized water and very finely dispersed oil i. e. some of the oil produced in the process but failing to condense within the shell or housing. The head end of the apparatus is defined as that end toward which the upper run of the conveyor moves. The tail end of the apparatus is defined as that end toward which the lower or return run of the conveyor moves.

The apparatus of our invention is characterized by a shell or housing in which there is an inclined conveyor with rise toward the discharge end for the solids. The carrier gas flows counter-current to the advance of oil shale undergoing treatment. The inlet for the heating gas is in the head end of the shell and hence beyond the position of the conveyor where it, the conveyor, is at its peak in rise and turning to discharge solids and reverse its direction of travel. The outlet for make-gas is positioned at the end remote from the heating gas inlet. The inlet for the oil shale to be treated is in the region intermediate the gas outlet and gas inlet. The shell has a sump for collecting the oil product, positioned in the base of the shell at the tail end and below the level of the upper run of the conveyor, so that the oil can drain to the sump. Means are provided to prevent the crushed solids from sliding from the conveyor and over-lying areas into the sump. Means are provided to prevent the heating gas from by-passing the crushed solids.

For a fuller understanding of the invention,

reference will now be made to the accompanyin drawing, wherein:

Figure 1 of the drawing is a central vertical section view with some elements in elevation.

Figure 2 is a front end view taken on line A-A.

Figure 3 is a vertical sectional view taken on line B--B of Figure 1.

In Figure 1 there are legends or indicia to aid the reader in the ready grasp or comprehension of the process for which the apparatus was principally intended. The solid line arrow indicates the direction of movement or flow of crushed solids and oil. The broken line arrow represents the direction of flow of the gases.

Referring more in detail to the accompanying drawings, more particularly Figure l and which represents the preferred form of the present invention, the reference numeral I designates the shell or housing of the retort to which is aifixed the shale hopper 2 provided with a rotary or equivalent seal 3. Positioned within the retort and extending longitudinally throughout much of its length is a drag chain, apron or equally eflicient conveyor 4; it possesses a slight incline toward the discharge end of the conveyor. The conveyor moves in the direction of the solid arrow, passing over the drive sprockets 5 at the head end of the retort, to the takeup shaft sprockets 6, up over to the idler sprockets l to the point of beginning. The drive sprockets are rotated by a suitable drive mechanism. Suitable guides or tracks may be provided for the operation of the chain or apron. Neither the guides or tracks, or the drive mechanism for sprocket 5 are shown in the drawing. Substantially the entire space between the three pairs of sprockets is surrounded by the closed polyhedral vessel 8. There is an inlet 9 for the introduction of heating gas at the upper part of the head end of the retort. The broken arrow with indicia shows the direction of flow of the heating gas through the moving shale bed. Depending from a housing Ill in the top of the retort shell and above the discharge end of the conveyor there are a series of chains I I for maintaining a more nearly vertical face on the advancing shale. Positioned within two other spaced housings I I! and II!" are flap plates I2 and I2 respectively, for pre venting channelling of heating gases in the event the advancing shale should settle. There is a louvered or perforated disengaging wall I3 depending from one wall of the hopper to a position just above the lower end of the upper run of the conveyor 6 closing the back end of the shale filled portion except for the space occupied by the conveyor at the bottom. At the back or tail end of the retort there is a gas outlet port I4 through which the retort gas is withdrawn. A knockout chamber has been provided just ahead of gas outlet port It for the puropse of removing agglomerated oil mist. The agglomerated mist drains vertically under gravity to the collection sump at the base of the equipment. Near the base of exterior wall Hi there is a dam or bafile IS the function of which will be more fully explained. A chamber for collecting oil retorted from the oil shale or volatile liquids recovered from other solids is formed by this baille I6 and two sloping sides of the polyhedral vessel 8. One of these two sides of this closed vessel, namely the lower side, forms a channel with the under wall I! of the shell, the purpose of which will be explained below. The level of oil in the chamber is dependent upon the height of the dam it which level should be such that the entire cross section of the channel l1 at the lower end is full. The bafile I6 also provides a chamber for drawing off produced oil through outlet I8. The oil collecting zone allows for any solid material to settle to the base of the sump. A clean-out trap 29 is provided under the oil sump for the removal of shale fines that may have washed down to the valve IS.

The endless conveyor 4 moves up the incline through the heat transfer zone, passing over the drive sprockets I, then returning through channel l1 into an oil seal. The endless conveyor then passes under the pair of lower sprockets 6 and upwardly over sprockets I completing the circuit. Sprockets 6 and I are submerged in oil. Due to the presences of the oil in the collection sump which acts as a seal chamber, gases cannot by-pass down the return channel H to the hopper 2 or gas outlet port M. The static pressure at the oil surface in channel 11' will be substantially the same as the pressure in the head end of the conveyor-exchanger retort. Therefore, a pressure differential will exist between this surface and the gas outlet port l4 and will be equal to the pressure drop across the shale bed. This will cause a difference in oil levels between that in channel l1 and that in the wide zone as is evident in Figure 1.

Referring to Figure 2 of the drawing it will be seen that the head end of the housing narrows toward its base forming vertical chamber 2I' for funneling the hot spent shale to the seal 22 for removal from the conveyor-exchanger retort.

The operation of the apparatus may be conducted as herewith explained.

The crushed, sized oil shale up to a six-inch maximum particle size is introduced to the surge hopper 2 through the feed and seal device 3. The shale moves by gravity through the hopper to the heat transfer zone, which is so designated in Figure 1 on the body of the conveyor bed 4, and is pulled up an incline by means of the conveyor as indicated by the solid arrow. As it progresses on the conveyor, the oil shale moving countercurrent to the heating gas introduced through inlet 9 is first pre-heated and then retorted until its temperature reaches about 1000 F. The shale may tend to settle slightly as it moves up the incline. To insure proper contact with the horizontally, slightly downwardly flowing heating gas, by-passing is prevented by the action of an occasional flap plate riding on top of the advancing shale bed. The retorted shale at about 1000 F. is carried over the discharge end of the con veyor and falls down into vertical chamber 2!, from whence it passes to feed and seal device 22, which provides a seal between the retort chamber and subsequent processing equipment which form no part of the present invention.

Retorting is accomplished by passing a stream of hot carrier gas through the advancing bed of oil shale. The flap plates riding on top of the shale bed prevent by-passing and insure proper contact of the gas with the shale. The carrier gas enters the head end of the retort at about 1100 F. and progressively surrenders its heat to the moving shale. The carrier gas with the increment representing the volatile products of retorting proceeds through the remainder of the shale bed, pre-heating the oil shale to re torting temperatures. At the same time, the gas stream is cooled and part of the condensible oil product is removed and runs down to a collection sump at the back end of the conveyor-exchanger retort. In this counter-current retortlng, shale aeeenoi;

in the area of introduction possesses the lowest temperature, whereas that at'the discharge end of the conveyor has the highest temperature. Oil retorted from the shale is condensed from the gas stream upon the cold, incoming shale, there-v by in turn pie-heating it. This condensation occurs principally in that portion of the retort adjacent the louvers or in that area. The condensed oil drains from the lower surface of the upper conveyor run into the oil collecting sump of the fixed closed vessel 8shown in Figure 1 of the drawing.

The gas stream leaves the shale bed through louvered or perforated disengaging wall l3 at temperatures above the pour point for the crude shale oil. This gas thereupon passes into a knockout space or zone where oil mist particles agglomerate and drop down to the collecting sump which contains the released liquid oil. Only a small percentage of the oil has remained uncondensed however after contact with the fresh shale. The uncondensed retort gas leaves the retort through the gas outlet port l5, and passes to processing equipment which is not shown since it forms no part of this invention.

A level of oil is maintained in the tail end of the retort so that the entire cross section of the channel contiguous to under-wall 20, at its lower end is full of oil. This provides a seal against carrier gas by-passing the shale bed down the return channel to the hopper 2 and gas outlet port is. The oil produced in the process is withdrawn from the tail end of the unit through outlet pipe 58. 'The oil level is maintained by flow over a weir 66. Any shale fines that may have washed down to the sump may be removed through the clean-out trap 20.

In the process, which has just been described, there is excellent heat transfer from the hot car rier gas to a cold bed of crushed shale. A hot gas can be cooled as much as 1000 F. in passing through a relatively short bed of crushed shale. Because of this last fact the provision of a short linear bed for retorting of shale is advisable. Moreover in surrendering its heat the vaporized shale oil condenses on the bed of crushed shale. In the process herein, wh ch is our own, there is provided a moving bed of cold shale which continuously supplies surface for cooling and condensing the vapors. Under normal working conditions, operating on crushed shale, about 75-85 percent of the oil released by heat should condense on the cold shale. In one method of operation it should be possible to recover crude shale oil at this point, relatively water free. Because water has a lower dew point than the crude oil then in this latter operation all but a few percent of it passes out as a part of the retort gas. By the qualifying adjective "cold as applied to shale is simply meant shale at the temperature of introduction into the hopper and prior to retorting i. e. without pro-heating. Our apparatus for retorting shale should require little or no process cooling water for product recovery. This is a marked advantage for processing oil shale or similar material in arid or semi-arid regions.

lhe apparatus of the present invention is compact. By the arrangement of the hopper intermediate the port of entrance for the heating gas and exit for the retort gas, plus the perforated disengaging wall to dam the shale pieces whereby a condensing surface of shale pieces is formed to contact the vapors and also to prevent their descent off the conveyor, we have provided features which set our invention apart from any previous apparatus.

Our apparatus loads satisfactorily enough to prevent by-passing of part of the carrier gas around the retorting bed. It also makes provision during travel of automatically riding plates to prevent the carrier medium by-passing the advancing bed.

Moreover the presence of the condensed oil in the cold portion of the shale bed can be utilized for a seal at the point of introduction of the raw shale feed.

Improved separation of liquid droplets from the cooled gas is effected by impingement on the particles of solid shale. The major portion of the released oil will condense on the incoming cold shalev and be recovered water free from the retort. This represents a major advantage in view of the serious emulsion-breaking difiioulties encountered with conventional oil recovering systems.

The apparatus of our invention can be used in other processes where solids such as Wood coal, lignite, tar sands, etc. are heated to obtain a liquid product.

The foregoing description of our invention is not to be taken as limiting our invention but only as illustrative thereof since many variations may be made by those skilled in the art without departing from the scope of the appended claims.

We claim as our invention:

1. A retort for the destructive distillation of oil shale and similar solid materials comprising an elongated shell, an endless belt conveyor disposed within said shell and inclined upwardly toward its discharge end, means for continuously feeding crushed solids through the top of said shell to the lower portion of the carry-run of said belt conveyor whereby said solid material is continuously carried upwardly as a pervious bed occupying substantially the entire cross section of said retort between the carry-run of said conveyor and the top of said shell, means for introducing re- 'torting gases into said shell adjacent the discharge end of said conveyor whereby said gases pass countercurrently through the continuously advancing bed of solids, means for withdrawing said retorting gases from said shell at the opposite end of said conveyor, the lower portion of said shell forming a basin for the collection of liquid products distilled from the solid material carried-by said conveyor, the lower end of said inclined conveyor being disposed within said basin, whereby said conveyor is cooled during its return run by immersion in the liquid contained therein.

2. A retort for the destructive distillation of oil shale and similar solid materials comprising an elongated shell, an endless belt conveyor disposed within said shell and inclined upwardly toward its discharge end, means for continuously feeding crushed solids through the top of said shell to the lower portion, of the carry-run of said belt conveyor whereby said solid material is continuously carried upwardly as a pervious bed occupying substantially the entire cross section of said retort between the carryrun of said conveyor and the top .of said shell, means for introducing retorting gases into said shell adjacent the discharge end of said conveyor whereby said gases pass countercurrently through the continuously advancing bed of solids, means for withdrawing said retorting gases from said shell at the opposite end of said conveyor, the lower portion .of said shell forming a basin for the collection of liquid products distilled from the solid material carried by said conveyor, the lower end of said inclined conveyor being disposed within said basin, whereby said conveyor is cooled during its return run by immersion in the liquid contained therein, a baiile compartment disposed between the carry-run and the return-run of said belt conveyor, the upper and lower walls of said bafiie compartment extending across said shell, parallel to, and closely adjacent to, the carry-run and return-run respectively of said belt conveyor, the lower end of said baflle compartment extending into said basin and being immersed in the liquid contained therein, whereby the bypassing of retorting gases around said bed of solid material is effectively prevented.

3. An upwardly inclined elongated shell, an endless conveyor with its carry run extending throughout the greater part of its length, said conveyor having a higher elevation at its upper and discharge end than at its other end, means to introduce a heating gas to the end of the shell at a locus in the zone of the discharge end of the conveyor, means to withdraw the spent heating gas from the lower end of the shell, means to introduce crushed solids into the shell at a locus intermediate the inlet and withdrawal means for the said gas, a discontinuous bailie depending from the top of the shell to a position aiiording only slight clearance with the carry run of the conveyor, means below the discharge end of the conveyor to remove the hot solids, a disengaging chamber for removal of agglomerated oil mist from the carrier gas medium, a chamber in the lower portion of the shell and below the level of repose of the solids on the conveyor for collecting liquid distilled from the crushed solids, and means to take off liquid from this chamber, a bailie compartment disposed between the carryrun and the return-run of said belt conveyor, the upper and lower walls of said baiile compartment extending across said shell, parallel to, and closely adjacent to, the carry-run and return-run respectively of said belt conveyor, the lower end of said baiile compartment extending into said basin and being immersed in the liquid contained therewhereby the bypassing of retorting gases around said bed of solid material is effectively prevented.

4.. A retort for the destructive distillation of oil shale and similar solid materials comprising an elongated shell having an upwardly inclined underside, an endless belt conveyor disposed within said shell and inclined upwardly toward its discharge end in such a manner that the return run thereof passes closely adjacent to and substantially parallel to the upwardly inclined underside of said shell, means for continuously feeding crushed solids through the top of said shell to the lower portion of the carry-run of said belt conveyor, whereby said solid materials are continuously carried upwardly by said conveyor as a pcrvious bed occupying substantially the entire cross section of said retort between the carryrun of said conveyor and the top of said shell, means for introducing retorting gases into said shell adjacent the discharge end of said conveyor whereby said gases pass countercurrently through the continuously advancing bed of solids, means for withdrawing said retorting gases from said shell at the opposite end of said conveyor, a basin in the bottom of said shell at the lower end of said inclined underside for the collection of liquid products distilled from the solid material car- 8, ried by said conveyor, the lower end of said inclined conveyor being disposed within said basin, whereby said conveyor is cooled during its return run by immersion in the liquid contained therein.

5. A retort for the distillation of oil shale and similar solid materials comprising an elongated shell having an upwardly inclined underside, an endless belt conveyor disposed within said shell and inclined upwardly towards its discharge end in such a manner that the return run thereof passes closely adjacent to, and substantially parallel to, the upwardly inclined underside of said shell, means for continuously feeding crushed solids through the top of said shell to the lower portion of the carry-run or" said belt conveyor, a pervious baffle extending from the top of said shell downwardly to the carry-run of said conveyor, said ballie being disposed immediately behind the point of introduction of said solid material whereby said baffie forms a supporting dam, causing said material to fill the cross section of said retort above said conveyor, whereby said solid material is continuously carried upwardly by said conveyor as a pervious bod occupying substantially the entire cross section of said retort between the carry-run of said conveyor and the top of said shell, rneans for introducing retorting gases into said shell adjacent the discharge end of said conveyor whereby said gases pass countercurrently through the continuously advancing bed of solids, a chamber directly behind sa-id pervious baffle for the agglomeration of liquid mists carried through said pervious bafile by the retorting gas stream, means for withdrawing said retorting gases from said chamber, a basin in the bottom of said shell at the lower end of said inclined underside for the collection of liquid products distilled from the solid material carried by said conveyor, the lower end of said inclined conveyor being disposed within said basin, whereby said conveyor is cooled during its return run by immersion in the liquid contained therein, a battle compartment disposed between the carry-run and return-run of said belt conveyor, the upper and lower walls of said baflle compartment extending across said shell, parallel to, and closely adjacent to, the carry-run and return-run respectively of said belt conveyor, the lower end of said baiile compartment extending into said basin and being immersed in the liquid contained therein, whereby the bypassing of retorting gases around said bed of solids is eiiectively prevented.

JQHN TRIPP.

LEWIS I-I. BRAKEL.

GEORGE D. GOULD.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,272,377 Catlin -l July 16, 1918 1,474,357 Gercke -l Nov. 20, 1923 1,534,737 Reed Apr. 21, 1925 1,639,417 Wallace Aug. 16, 1927 1,964,877 Hereng July 3, 1934 2,448,223 Lantz Aug. 3. 1948 FOREIGN PATENTS Number Country Date 188,686 Great Britain Nov. 17, 1922 570,295 Germany Feb. 14,1933

Claims (1)

1. A RETORT FOR THE DESTRUCTIVE DISTILLATION OF OIL SHALE AND SIMILAR SOLID MATERIALS COMPRISING AN ELONGATED SHELL, AN ENDLESS BELT CONVEYOR DISPOSED WITHIN SAID SHELL AND INCLINED UPWARDLY TOWARD ITS DISCHARGE ENDS, MEANS FOR CONTINUOUSLY FEEDING CRUSHED SOLIDS THROUGH THE TOP OF SAID SHELL TO THE LOWER PORTION OF THE CARRY-RUN OF SAID BELT CONVEYOR WHEREBY SAID SOLID MATERIAL IS CONTINUOUSLY CARRIED UPWARDLY AS A PREVIOUS BED OCCUPYING SUBSTANTIALLY THE ENTIRE CROSS SECTION OF SAID RETORT BETWEEN THE CARRY-RUN OF SAID CONVEYOR AND THE TOP OF SAID SHELL, MEANS FOR INTRODUCING RETORTING GASES INTO SAID SHELL ADJACENT THE DISCHARGE END OF SAID CONVEYOR WHEREBY SAID GASES

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