US2432135A - Distillation of oil shale in fluidized condition with simultaneous combustion of spent shale - Google Patents

Description

F. T. BARR DISTILLATLONDF OIL SHALE IN FLUIDIZED CONDITI WITH SIMULTANEOUS COMBUSTION OF SPENT SHALE Filed April 17, 1943 Dec. 9, N4?.

Patented Dec. 9, 1947 oFFicE DrsTmLATIoN oF oILsHALE IN FLUiDIzED coNDrrroN WITH sIMUL'rANEoUs CoM- Us'rIoN or sPENT sHALE Frank T. Barr, Summit, N. J., assigner to Standard Oil Development Company, a corporation of Delaware c "gld" Application April 17, 1943, SerialNo. 483,397

9 Claims.

The present invention relates to improvements in the art of recovering petroleum oil from minerals such as oil shales. oil sands, and the like,

' and more particularly it relates to a continuous operation in which the oil may be recovered in a method which is more expeditious and cheaper.

In general, my present invention is one inv which hydrocarbon oils are recovered from shale by charging the shale in crushed and/or powdered condition into a stream of air and thereafter carried by the stream of air into the reactionvessel Where the shale is subjected to temperatures of GOD-1100* F.. whereupon the process results in the formation of hydrocarbons. It should be pointed out that the ordinary grade of shale does not contain hydrocarbons but rather contains compounds of carbon, hydrogen, oxygen, nitrogen, and sulfur in looselyvbound form, ordinarily referred to as kerogen. These compounds, however, during heating within the temperature range indicated, liberate ammonia and sulfur compounds and therefore produce relatively pure residual hydrocarbons.

My invention will be best understood by reference to the accompanying drawing in which I have shown diagrammatically a. layout in which a preferred modification of my invention may be successfully performed.

Referring in detail to the drawing, I represents a feed hopper into which crushed or ground` shale is introduced and thence discharged into an elongated standpipe 3 having a plurality of branch pipes or taps through which taps air may be discharged into the column of shale in order to fluidize the powdered shale, that is to say, to impart to it the ow characteristics resembling a true iiuid. If the shale, however, has an average particle size of 1A inch to 1/2 inch, it may iiow without aerationf i. e., without the necessity of supplying air through taps 5. At a point near the bottom of the standpipe 3 a ow control valve l0 is provided by which I may control the ilow of powdered shale through the hopper I into the standpipe 3. Air preheated to a temperature of from about 100 F. to 600 F. is discharged into pipe I2 where it admixes with the i'luidized shale from standpipe 3 to form a suspension, which suspension is vthen discharged into the reactor 20 through a distributing foraminous member 2|.

At the start o`f the operation it is necessary, by means of some external source, to ignite the shale as it enters the reactor 20 and to cause the burning of a portion of the carbonaoeous materials contained therein. This burning, of course, vadds heat to the reactor and this heat causes the 2 aforementioned chemical transformation resulting in the production of ammonia, sulfur compounds, normally gaseous hydrocarbons and hydrocarbons boiling in the gasoline, gas oil, and fuel oil ranges. That is to say, the shale as it comes into the reactor is caused to partially burn and during the burning at least a portion of the desired hydrocarbons is released as the shale passes upwardly into the reactor. The superficial velocity of the gases within the reactor is xed within the limits of say 0.5-15 ft. per second, depending upon the size of the ground shale. For powder, velocities of 1-3 ft. per second are preferably used so as to form within the reactor a dense, fluidized, turbulent mass of powdered shale in gas, the density of which may be from 15-25 lbs. per cu. ft. For larger particles, 3-10 ft. per second may be required to give optimum fluidity. Due to the controlled velocity of the gases, the shale undergoing chemical transformation and/or distillation forms a dense phase upper level at L. Above L I provide, in my preferred modication, a disengaging chamber 25 of greater diameter than reactor 20 where the velocity of the gases and/or vapors is reduced to a small fraction of the velocity in the distillation zone (say to Vg ft. per second) in any event, sufcient so that the gases will not support the shale and the latter gravitates into the main body of the reactor in the space designated 20, with the result that the gases withdrawn through drawoi pipe 30 are substantially freed from entrained solids. If necessary, to minimize cracking in the disengaging zone, the reaction may be quenched as by injection of steam or oil into the reaction zone.

Referring again to the reactor 20, it is pointed out that there are two concurrent and complementary reactions taking place within said reactor, namely, (a) burning, and (b) distillation or chemical transformation. The heat.released in (a) serves to supply the endothermic heat necessary for the chemical transformation (b),

so that within a single vessel I both distill and.

burn the shale. It will be understood that after the process has been in operation the spent shale, that is the shale from which the volatilizable materials have been eliminated by the heat treatment, may yet contain some fixedv carbon which will be utilized in the burning step (a) in providing the heat necessary for the operation taking place as described under (b). It should be borne in mind that steps (a) and (b) take place more or less concurrently and contiguously, so that .the heat released by exothermic reaction tically complete removal of carbonaceous material from the shale before discharge. Introduction of air at one or more joints through taps 21 in pipe 28 may be desirable to provide a gas seal and. if necessary, to tluidize the shale for easy withdrawal through draw-off pipe 28. When working at its best my process forms no clinker,

i but if some is formed it may be withdrawn through 24.

Referring to the gaseous products which are withdrawn through line 30 and which contain nitrogen, hydrocarbons, CO2, steam and other products of combustion, preferably they are passed through dust collector 32 in order to removel therefrom entrained fines which may be withdrawn through draw-oil pipe 33, while the vapors substantially freed of entrained solids may then pass through a heat exchanger 40 in countercurrent heat exchange with atmospheric air introduced through line 42, withdrawn through line 43 and thence discharged into line l2. The partially cooled products are withdrawn from heat exchanger 40 through line 45 and they may be passed through waste heat boiler 41 to recover a portion of their sensible heat for use in some other system, thence passed through a feed bottoms heat exchanger 48, then further cooled in a water cooler 50 and thence discharged into a stripping tower 52 through a feed inlet 5| where they are treated with a lean oil introduced through line 55, which lean oil serves to scrub the hydrocarbons out of the gases, and the thus scrubbed gases consisting essentially of flue gas, ammonia, and sulfur compounds are then rejected from the present system overhead through line 60. The fat oil is withdrawn from the scrubber through line 62, passed through the cooler 48, after which the oil is passed preferably through a centrifuge, settler or other filtering means 65 to separate the powder which has not previously been separated. The powdered material iswithdrawn from the system throughline 6B. The filtered oil is then withdrawn through line 10, heated in a heat exchanger 12 and thence it is discharged through line 15 into a fractionating column 80. The desired hydrocarbons, that is to say, hydrocarbons boiling within the gasoline range are recovered from fractionator 80 through line 85 and these may be refined in the usual manner to form an automotive gasoline. 'lne bottoms from fractionator 80 are withdrawn through line 90, are cooled in heat exchanger 12, further cooled in water cooler 82 and thence passed by line 55 to scrubber 52 and processed in the manner previously described. A portion of the bottoms in line 90 may be continuously withdrawn from the system through pipe H0 and used for any suitable purpose, such as a fuel oil.

It should be pointed out that the gasoline which is recovered from fractionator 80 through line 85 is superior to ordinary virgin gasoline and resembles catalytically cracked gasoline, the spent shale having some catalytic eiect in cracking. Also, the relatively high temperatures 4 which may be employed in the reactor 2l innuences the character of the gasoline produced.

In order to illustrate my invention more fully. I may refer to a good quality of shale which has 42 gallons of oil available per ton of shale. If the shale is ground to a particle size of say mesh or larger and then fed into the reaction zone as indicated, it will require about 200 lbs. of air or the burning of about 40 lbs. of oil to maintain the reaction at around 800 F. Depending of course on numerous conditions, these quantities may vary. that is to say, the amount of air may vary from 100 to 400 lbs. per t0n of shale charged, and the temperature in the zone may vary from 800 F. to 1000 F.

I consider one of the main advantages of my present invention to reside in the feature that I both burn spent shale and distill fresh shale in the same vessel or retort in the form of a dense fluid mass, thus avoiding expensive heat transfer equipment, that is recovery equipment and the like, as well as saving structural steel. Another advantage, and perhaps more important than the preceding one, is that temperature control attainable in the reaction zone by my process far exceeds the temperature control obtained in any type of process, such as in a fixed bed operation. I am enabled to maintain virtually any temperature I desire within the reaction zone. Insoiar as I am aware, it has been the custom to subject the raw shale to distillation in one vessel, withdraw the spent shale from this vessel and burn it in a second vessel. heat of the spent shale is to be employed it may of course be transferred back to the first vessel and to make the process feasible large amounts of insulation are necessary to prevent heat losses during the transfer. I have avoided the necessity for providing two separate vessels for the process as hereinbefore indicated.

It will be obvious to those skilled in this art that numerous modifications of my invention will readily suggest themselves to those familiar with this art.

What I claim is:

1. A continuous process for recovering oil from shale which comprises continuously charging ilnely divided oil shale into a stream initially comprising an oxygen-containing gas and substantially fiuidzing the oil shale in said stream, passing the stream of thus fiuidlzed shale upwardly continuously into a reactor, maintaining the iluidized shale in said reactor in a fluidized state for a period, meanwhile promoting sunlcient combustion of combustible matter in the iluidized shale in said reactor to maintain a temperature therein of about 800 F. to about 1000 F., thereby causing the formation of gas and condensable volatile matter from said oil shale. continuously removing the said stream along with the oil shale reaction products overhead and separately recovering therefrom condensable hydrocarbons, and withdrawing the spent shale from the lower portion of the mass of oil shale iiuidized in said reactor.

2. Process as defined by claim 1 wherein said stream initially comprising an oxygen-containing gas is preheated to a temperature in the range of from about 100 F. to about 600 F.

3. Process as defined by claim 1 in which the velocity of the stream comprising oil shale reaction products which is removed overhead is substantially reduced in said reactor prior to removing said stream from said reactor, whereby entrained dust is removed therefrom in said reactor.

If the sensible I 5 4. Improved process of distilling and burning shale in a single reactor which comprises charg-y ing finely divided oil shale into a stream initially comprising an oxygen-containing gas and substantially iiuidizing the shale in said stream under conditions to mix about 100 to 400 pounds of air per ton of shale charged, passing this stream of fluidized shale upwardly continuously into a reactor, maintaining the uidized shale in said re, actor in a fiuidized state for a period, meanwhile promoting sucient combustion of combustible matter in the uidized shale in said reactor to maintain a temperature therein of about 800 F. to 1000 F., thereby causing the formation of gas and combustible volatile matter from said oil shale, continuously removing the said :stream along with the oil shale reaction products overhead, and separately recovering therefrom condensable hydrocarbons, and withdrawing the spent shale from a lower zone of the mass of Oil shale uidized in said reactor.

5. Process as dened by claim 4 wherein said stream initially comprising an oxygen-containing gas is preheated to a temperature in the range from about 100 F. to about 600 F.

Y 6. Process as dened by claim 4 in which the velocity of the stream comprising oil shale reaction products which is removed overhead is substantially reduced in said reactor prior to remov-l ing said stream from said reactor, whereby entrained dust is removed therefrom in said reactor.

'1. Process as defined by claim 4 in which sufcient steam is introduced into the reactor, whereby cracking of the reaction products is substantially prevented.

i 8. A continuous method for distilling oil shale which comprises charging the said oil shale in subdivided form to an elevated point, continu-l ously withdrawing said oil shale from said elevated point downwardly in a restricted stream to a distilling zone located at a point below said elevated point, causing a. gas to be injected in said restricted stream at spaced points thereof to facilitate the uidity of said oil shale, injecting a quantity of an oxygen-containing gas preheated to a. temperature in the range from about 100 to 600 F. into the oil shale at the bottom of said restricted stream to induce in conjunction with the pressure developed in the restricted i drocarbon oil vapors therefrom, controlling said combustion so as to adjust the temperature prevailing in the distilling zone to a level of the order of from 800 to 1000 F., continuously withdrawing said oil vapors, cooling, condensing and collecting the condensate.

9. A continuous method for distilling oil shale which comprises charging the said oil shale in subdivided form to an elevated point, continuously withdrawing said oil shale from said elevated point downwardly in a, restricted stream to a distilling zone located at a point below said elevated point, causing a. gas to be injected into said restricted stream at spaced points thereof to facilitate the uidity of said oil shale, injecting a. quantity of an oxygen-containing gas preheated to a temperature in the range from about 100 to 600 F. into the oil shale at the bottom of said restricted stream to induce in conjunction with the pressure developed in the restricted stream, a natural flow of the said oil shale into the said distilling zone, regulating the velocity of the gas within said distilling zone within the limits of from about 0.5 to 15 ft. per second whereby a, fluidized mass of solid material is formed, causing substantially complete combustion of the nonvolatile carbonaceous constituents of the shale in said fiuidized mass by means of said oxygencontaining gas to develop all the heat required in said distilling zone for the volatilization of hydrocarbon oil vaporstherefrom, introducing sumcient steam into the iiuidized mass in the reaction zone to prevent the temperature therein from rising above about 800 to about 1000 F., continuouslywithdrawing said oil vapors, cooling, condensing and collecting the condensate.

FRANK T. BARR.

BJEIFERENCESV CITED The following references are of record in the file of this patent: f

UNITED STATES PATENTS Number Namel Date 1,983,943 Odell Dec. 11, 1943 1,937,552 Davis Dec. 5, 1933 1,984,380 Odell Dec. 18, 1934 2,304,827 Jewell Dec. 15, 1942 2,302,209 Goddin Nov. 17, 1 942 2,311,564 Monday Feb. 16, 1940 1,180,217 White Apr. 18, 1916V 727,030 Tilghman May f5, -1903 FOREIGN PATENTS Number Country Date Australia Aug. 20, 1942

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