US2560403A

US2560403A - Method for processing carbonaceous solids

Info

Publication number: US2560403A
Application number: US529240A
Authority: US
Inventors: Maurice H Arveson
Original assignee: Standard Oil Co
Current assignee: Standard Oil Co
Priority date: 1944-04-03
Filing date: 1944-04-03
Publication date: 1951-07-10
Anticipated expiration: 1968-07-10

Description

y 1951 "M. H. ARVESON METHOD FOR PROCESSING CARBONACEOUS SOLIDS Filed April 5, 1944 3 Sheets-Sheet l July 10, 1951 M. H. ARVESON METHOD FOR PROCESSING CARBONACEOUS SOL IDS Filed April 3, 1944 3 Sheets-Sheet 2 w y M K e 6 w y a w w m y 5 July 1Q, 1951 M. H. ARVESON 0 urzmon FOR PROCESSING CARBONACEOUS SOLIDS Filed April :5, 1944 s Sheets-Sheet 5 Patented July 10, 1951 METHOD FOR PROCESSING CARBO- NAGEOUS SOLIDS Maurice H. Arveson, Flossmoor, 111., assignor to Standard Oil Company, Chicago, 111., a corporation of In 7 Application April 3, 1944, Serial No. 529,240

This invention relates to the recovery of volatile material from naturally occurring carbonaceous substances and it pertains more particularly to a process for the optimum utilization of the hydrocarbon content of such carbonaceous substances as coal, shale, lignite, peat, oil sands, natural gas, and the like.

In accordance with my invention the carbonaceous substances may be utilized for the recovery of liquefiable hydrocarbons and particularly aromatics such as benzol, toluol, etc. Alternatively the carbonaceous substances may be utilized for the preparation of gaseous products and particularly carbon monoxide-hydrogen mixtures which may be utilized per se as a gaseous fuel or which may be converted by known synthesis processes into normally liquid hydrocarbons, alcohols or other valuable materials.

An object of my invention is to provide improved methods and means for the maximum utilization of hydrocarbon values from gaseous and/or finely divided solid carbonaceous materials in a simple but efiicient continuous'process. A further object is to provide a simple apparatus using a minimum of moving parts and critical materials. Another object is to provide an improved process wherein the heat required for effecting the decomposition or transformation of carbonaceous material is obtained from the direct burning of carbonaceous material in a separate zone. A further object is to provide a method and means for decomposing and/or transforming carbonaceous material .wherein hot powdered solids absorb heat in a combustion zone and are then transferred to a decomposing or transforming zone to liberate their stored heat and thus supply the endothermic heat required for the decomposition and/or transformation of the carbonaceous material in the decomposing zone. A further object is to provide an improved method and means for the production of hydrocarbons, particularly aromatic hydrocarbons, gases such as carbon monoxide-hydrogen mixtures, coke, etc.

A particular object of my invention is to provide a method and means for recovering valuable products from gaseous or finely divided solid carbonaceous materials in a zone wherein a suspended turbulent dense phase of hot finely divided solids is maintained. It is an important object of my invention to provide an improved method whereby carbonaceous material can be converted into coke and valuable conversion products at high temperature without the necessity of transferring heat through metal walls and without diluting the conversion products with the gases resulting from the heating step. In other words, my object is to eiiect the production of hydrocarbons, water gas, carbon monoxidehydrogen mixtures, etc. by endothermic conver- 9 Llaims. (Cl. 48-202) sion of carbonaceous materials in the absence of any substantial amounts of nitrogen and without having to transfer heat through metal walls while at the same time utilizing ordinary air combustion of carbonaceous materials for supplying the required endothermic heat. Other objects and advantages of my invention will become apparent from the following detailed description.

Briefly stated, my invention contemplates the burning of a carbonaceous material with air in the presence of a suspended dense turbulent -mass of finely divided solids whereby the solids are heated to high temperature. The hot solids in fluidized state are withdrawn from the combustion or heating zone and transferred to a decomposing or transformation zone wherein these solids supply the endothermic heat of conversion and if the solids are comprised of incandescent coke they may likewise supply reactant material for endothermic conversion with steam to produce carbon monoxide-hydrogen mixtures. The gases or vapors leaving the decomposing zone are not contaminated with the combustion products from the heating zone and the endothermic heat of conversion is supplied within the suspended dense turbulent fluidized solids mass. The temperature of the decomposing zone may be regulated by controlling theamount and temperature of cycled solids, lower temperatures in this zone being advantageous for the recovery of normally liquid hydrocarbons while higher temperatures and the presence of steam are required for the production of carbon monoxide-hydrogen mixtures. carbonaceous deposits or residues formed in the decomposition zone may be at least partially burned in the heating zone since a fluidized solids stream is continuously cycled from the dense solids phase in the decomposing zone back to the heating zone in amounts sufiicient to balance the transfer of hot or incandescent solids from the heating zone to the decomposing zone. In one embodiment of my invention I may eifect both the recovery of normally liquid hydrocarbons such as aromatics and the production of carbon monoxide-hydrogen mixtures by employing separate decomposing zones operating at difierent temperature levels in a closed circuit with the heating zone.

The invention will be more clearly understood from the following detailed description read in conjunction with the accompanying drawings which form a part of this specification and in which:

Figure 1 is a schematic flow diagram of a heater-coker system with the heating and coking sections being shown in vertical section.

Figure 2 is a schematic flow diagram of. a system employing two separate decomposing zones for the separate production of hydrocarbons and a carbon monoxide-hydrogen gas mixture, and

Figure 3 is a schematic flow diagram of a unitary system wherein the heating zone surrounds the decomposing zone.

Referring to the drawings in general, the finely divided solids which may be coal, shale, oil sand or the like are dispersed in a gaseous medium by any one of a number of well known methods. Such gaseous medium may be steam, flue gas or a light hydrocarbon gas or any other gas suitable as a carrier. In one such method the raw material is discharged from the mill into a bin, cyclone separator, or receiver at the top of a standpipe.

The top of the standpipe can be provided with a suitable cyclone and enlarged hopper to effect the separation of the powdered raw material from the carrier medium. The powdered raw material .maintained in the standpipe is in an aerated condition resulting from the injection of an aerating fiuld near its base. The head of the fluidized material within the standpipe is used to introduce the particles in the system. The powdered raw material is passed through a metering valve and is picked up by a stream of a gas. Other means such as lock hoppers, star feeders, and the like can be used for introducin the powdered raw material into the several zones.

Whatever the means of dispersion, the raw particles are introduced into an enlarged chamber wherein the recovery of the hydrocarbon values is effected by distillation and/or decomposition. This reaction chamber is of such size and shape as to maintain the material rich in hydrocarbons and the hot residual material in a turbulent dense fluent phase therein. The inert gaseous material introduced into the recovery zone with, or in addition to, the raw material passes upwardly through the residual material at such a velocity as to maintain a turbulent dense suspended solids phase. Other vapors or reactant gases likewise can be passed upwardly therethrough which supplement the carrier medium in maintaining the dense turbulent phase. The vessel is designed so as to give the time of contact necessary to recover the hydrocarbons and to permit the continuous withdrawal of a mixture of denuded and residual matter from a low point in the dense phase.

The powdered coal, shale, or the like, introduced into my system is referred to herein as being the raw material. The solids from which substantially all the volatilizable hydrocarbon values have been recovered are referred to as being denudedsolids. The solids which are recycled to supply the heat necessary for the recovery of the hydrocarbons from the raw material is referred to as being the residual material or residue. The denuded material while mixed with recycled residual material is burned with an oxygen-containing gas to produce the hot residual material. It is apparent that the material withdrawn from the reaction zone will include both the recently denuded and the recycled residual material and that all three raw, denuded, and residual will probably be introduced into the decomposing or heating zone to some extent. In fact to maintain heat balance it may be desirable to introduce a portion of the raw solids into the heating zone directly.

There are many large power stations that burn tremendous quantities of powdered coal and it would make little difference to these stations whether they burn coal or powdered coke. Therefore, it is contemplated that the powdered 4 coal now normally charged to the burner could be picked up by steam from the existing hoppers and introduced as the raw charge for my process. Seventy to ninety per cent of conventional powdered coal passes a 200 mesh screen. When using conventional powdered coal as the charge to my process, I prefer to employ gas velocities in the decomposition or reaction zone of between about 0.5 and about 3 feet per second. For example, between about 1 to 2 feet per second. The raw coal should be maintained within the recovery zone for a time suilicient to effect the volatilization of the hydrocarbons and this normally 7 takes place in less than about one minute. A uniform temperature prevails throughout the heat decomposition zone by virtue of the dense turbulent fluent phase and may be maintained between about 1000 and about 1500 F. or higher, for example, at about 1200" F. The high temperature is maintained in the decomposition zone by recycling a high ratio of residual material to raw material. The temperature difference between the heater and decomposing zones will determine the recycle ratio or vice versa for a given raw material feed rate. This ratio should be between about one and to one. For example, in the case of coal, ratios of between about 10 and 50, and in the case of shale between about 5 and 10 can be used. With the temperature of the decomposing zone determined, the heater zone may then be operated at the required temperature to balancethe system. Other variables which influence the optimum recycle ratio of the residual material are the composition of the raw hydrocarboncontaining substance, the sensible heat of the recycled residual substance, the desired residence time within the decomposition zone and the like. In any event, the ratio of the residual substance to the raw material is at least sufficient to volatilize the hydrocarbons and where desired is sufllcient to supply the heat of conversion of the volatilized material to produce optimum amounts of the desired product.

At a temperature between about 900 or 1000 F., and about 1500 F. or higher the predominant effect is the decomposing of the raw solids (the term decomposing is expressly defined to include distilling). A non-oxidizing or inert gas such as light hydrocarbons can be used to maintain the solids in a dense turbulent suspended phase. When steam is present, and particularly at the higher temperatures within this range, carbon and steam readily react to form hydrogen and carbon oxides. Thus the temperatures in the reaction zone may be such that steam is substantially completely converted by reaction with carbonaceous material to form hydrogen and carbon monoxide. Concurrently there may be a distillation or coking of the raw solids. Since this conversion and coking are both endothermic, heat must be supplied to the reaction zone and such heat is supplied by cycling incandescent coke particles or other hot solids from a burning or heating zone to the reaction zone. The heating may be effected by burning a portion of carbonaceous solids, or by burning a gaseous carbonaceous material with coke or other solids, the solids acting as the heat carrier. Gaseous carbonaceous material such as methane can be introduced into the incandescent coke bed alon with the steam where the object is to produce carbon monoxide and hydrogen. Coke may be deposited in the decomposing zone by the reactions of normally liquid or normally gaseous l6 hydrocarbons instead of or in addition to re- When steam and methane are both present there will result oxidation of methane with steam to produce three volumes of hydrogen and one volume of carbon monoxide at temperatures above about 2000 F. in the absence of catalyst, or at 1400 to 1800 F. in the presence of known catalysts such as nickel. With coke and steam the reaction or decomposition results in the production of a 1:1 mixture of hydrogen and carbon monoxide. These reactions can be conducted simultaneously within the same or separate zones and by controlling the relative amount of reactants which is converted by the respective reactions, the proportion of hydrogen and carbon monoxide in the net mixture can be controlled. If hydrogen is desired, the gaseous product mixture can ,be subjected to a catalytic contacting with additional steam for converting carbon monoxide into carbon dioxide and producing further hydrogen, the carbon dioxide being removed by suitable scrubbing agents.

The density of the solids particles in my system will vary greatly from porous coke on the one hand and 'oil sands or shale on the other. With slight aeration, i. e. with gas or vapor velocities of between about 0.05 and about 0.5 foot per second, the bulk density of dense phase solids will usually be in the order of magnitude of between about 75% and about 95% of the density of the finely divided material when measured in a settled condition. With the vapor velocities of between about 1 and 3 feet per second the particles are maintained in a dense turbulent suspended phase and the bulk density of the dense turbulent suspended phase will ordinarily be between about 30 and about 90% usually about 40 to 70% of the apparent density of the settled materiai. With higher gas velocities, i. e. the velocity existing in transfer lines, the particles are in a dilute dispersed phase. The light dispersed phase in the upper part of the decomposing and heating zones is not more than 30% and is usually less than about 10% of the bulk density of the dense turbulent fluent phase maintained within the lower part of the decomposition or heating zones.

In most cases the bulk of the solids separate from the gases in the upper portion of the decomposing or heating zones. The separated material is accumulated in a dense turbulent suspended phase and transferred therefrom over a weir or through one or more overflow pipes or standpipes. Where the transfer is completely in the dense phase it may be in either direction. The dense phase also prevents the uncontrolled flow of gases from one zone to another. Denuded and residual particles may be further separated from the gases leaving the decomposing or heating zones by centrifugal or other means.

The separation zone at the top of the decomposition zone and/or the cyclone separator equip ment is adequate to remove substantially all of the denuded and residual particles from the product gas stream leaving the decomposition zone. These gases pass through one or more waste heat boilers, coolers and the like, to reduce the gases to the proper temperature for absorption and are then passed to an absorber where they are contacted with an absorber oil to separate any liquefiable constituents from the gases. An intermediate solids and tar separator may be interposed before the absorber. The unabsorbed gases removed overhead comprise essentially hydrogen 6 and carbon monoxide suitable for hydrocarbon synthesis. When coke is reacted with steam at a temperature above about 1200 F. in the absence of raw solids, the product consists essentially of hydrogen and carbon oxides. If desired, a portion of the water gas can be sent to the heating zone and burned with air. Use of gas for this purpose ordinarily will be confined to those cases where there may be a deficiency of carbonaceous combustible material in the denuded material going to the heater such as may be the case in very low grade shales or sands.

Li'gnite is a particularly useful material for my process. It exists in either surface or lightly covered deposits and can be mined economically on a large scale. It has much of the appearance of coal ranging from black to brown in color and is of relatively low sulfur content, in some cases there being no detectable sulfur in the gaseous products. The main diierences between lignite and coal are that lignite contains between 35 and 45% moisture and on a dry basis has a lower B. t. u. value per pound than coal. The lignite can be supplied to the decomposer or coking zones wherein a fluent bed of incandescent hot coke or other hot solids is maintained. The water content of the lignite provides water vapor which reacts with the lignite coke to produce hydrogen and carbon monoxide. A portion of the coke can be continuously withdrawn to a burning zone wherein a portion of the coke is consumed by burning in air to produce additional incandescent 45% hydrogen and 45% CO to about 60% hydrogen, 10% .CO and 30% CO2.

Natural gas may serve as at least a part of the carbonaceous material in my process, particularly gases consisting essentially of methane. The solids in this case may be coke particles or inert or catalytically active solids, depending on the type of products desired.

Another source of raw carbonaceous solids for my process is oil impregnated sands, for example, of the type to be found in the Athabaska region of Alberta Province, Canada. The deposits can be described as an impregnation of beds of sand and clayey material by a, heavy oil. The bituminous sand is a compact material, but if lumps are removed from the bed they are found to yield to pressure and break into a great num ber of smaller particles. The individual grains of sand and clay range between about 30 and about 200 mesh and particles of this size are efiectively treated in fluid systems of the type described in connection with this invention. The oil does not appear to be a pore-space filling, but resembles a film or envelope around the individual grains of .sand in concentrations ranging as high as about 25%.

Sands having at least about 9.5% oil are particularly useful in fluid coking since the heat for the recovery of the hydrocarbon content can be supplied by burning the coke remaining on the sand in a separate zone and contacting the raw sand with the hot residual sand in a dense turbulent phase. About 25% bated on the crude oil is converted into coke which is consumed in the separate heating step. Other means which have been employed in recovering the hydrocarbon content from this type of sand include washing or contacting with steam. If the consumption of the residual coke is undesirable, it is contemplated that the two methods may be combined wherein heat can be recovered from the spent sands to supply steam for the washing technique.- Thus part of the oil can be recovered by the hot fluid solids technique and part by washing. The heat recovery from the hot residual sand may be effected by waste heat boilers or by directly contacting with water. It should be understood. however, that I contemplate supplying the oil sand to the system and processing it in a manner analogous to that described in connection with powdered coal or shale.

With particular reference to Figure 1 wherein one form of apparatus is diagrammatically illustrated, the substance to be treated, for example, powdered coal or coke, oil sand. and the like, is discharged into a combined separator-hopper II] at the top of a standpipe H. The powdered coal in this standpipe is maintained in an aerated condition by the injection of an aerating fluid, such as steam, by line l2 near the bottom of the standpipe H. The powdered coal passes downwardly through the standpipe'and through a metering valve l3. The powdered coal is picked up in an optimum quantity of steam, and passes along line I4 where it joins a stream of powdered incandescent residual coke withdrawn from the heater H: by line IS.

The combined stream of powdered coal, incandescent coke and steam is introduced into the recovery chamber or coker I! by line IS. The coker or recovery chamber I1 is of such size and shape as to permit a major amount of finely divided coke to accumulate within the coker chamber IT in a dense turbulent phase. Upward gas velocity of the order of one to two feet per second, for example, are suitable in this coker to maintain the dense turbulent phase. The coke is withdrawn downwardly from the coker ll through conduit 2|. A valve 20 can be used to control the flow of the powdered coke into the transfer line 22. The air introduced by line 23 carries the finely divided solids through line 22 into the heater I5, attains the proper temperature level and maintains the dense turbulent phase therein. The bulk of the incandescent residual coke is continuously separated from the flue gases within the chamber 15, the gases being removed overhead by conduit 24. The gases may be burned under furnaces to utilize the calorific value of the gases as well as the suspended coke particles carried out of the chamber IS. The net productionof coke will ordinarily be removed from the system by this means. A suitable tap, however, can be provided for withdrawal of coke directly from the dense phase in either zone or from transfer line 22, for example.

The two contacting chambers I5 and I! can be constructed of fire brick and ordinarily will require very little structural steel bracing. The conduits may be constructed of ceramic tile and the like. Each of the zones is provided with a sloping bottom 26 and 25 to facilitate the withdrawal of the powdered initial coke or the hot residual coke, respectively.

In view of the rapid heating and easy control of the heating temperature within the coker l'l it is possible to recover a liquid of improved product distribution, i. e., one which has a higher percentage of benzol, toluol, xylol and far less tar and heavy oils than conventional coker liquids. In this process, unlike conventional coking, coal is heated practically instantaneously to decomposing temperatures, thus eliminating the distillation period of conventional coking processes. Thus very heavy materials boiling up in the neighborhood of 900 F. and higher pass upwardly through the hot zone and there is a substantial amount of decomposition of these higher boiling materials to benzol, toluol, etc. Another advantage of this process over that of conventional coking is that the nitrogen (from air ordinarily required to effect partial combustion of the coal and volatilized matter) and other inert contents of the off-gases not readily condensible can be kept at a very low figure since they are diluted only by such small quantities of air or nitrogen that enter the coker I! with the powdered residual coke by line l8. This can be reduced further by stripping the hot coke with steam introduced by line 21. Unconverted steam introduced into the coker is condensed from the product stream and can be recycled as process water or steam.

A plurality of cyclone separators 28 can be provided within the coker l1 and the separated coke returned to the dense turbulent powdered coke phase. The coker gases and cracked products are withdrawn from the decomposition chamber I! by conduit 29 and may be quenched by the introduction of suitable quenching medium, such as water or tar oils, by quench line 30. The quenched product stream is then introduced into the separator 3|. The gaseous products are withdrawn from the separator 31 by line 32, cooled by passing through cooler 33 and introduced into a suitable absorber. An aromatic fraction produced by the process can be used as the absorber oil. The liquid product is withdrawn from the separator 3| by line 34 and passed to suitable distillation and fractionating equipment for recovery of the various fractions. When phenols are present the separated liquid may include emulsions with water. The removal of a 5 bottoms by distillation will facilitate a subsequent water separation. A slurry of coke particles and tar is removed from the bottom of the separator 3| by line 35' and can be recycled to the coker II. If desired, the separator 3| can be operated to remove water and coke in which case a slurry of coke and water can be withdrawn and passed to a suitable coke settler (not shown).

Temperatures between 1800 and 2500 F. are readily attainable by burning powdered coke or coked solids in a heater, and the temperature can be controlled by the amount of oxygen made available to the heater. In the embodiment described above, the temperature of the hot solids and the recycle rate of the hot solids between the heater and the decomposing zone are controlled to maintain a temperature between 1000 and 1500 F., and higher, within the decomposing zone. The inert gases, such as tall gas recycled from the coking-recovery system, are used to maintain the dense turbulent solid phase in the decomposition zone. Conversion products comprising aromatic hydrocarbons and methane are obtained. When operating under these conditions in the presence of steam, carbon oxides and hydrogen are also formed. Within the temperature range described, the ratio of carbon monoxide to carbon dioxide increases with increased temperature, and at 2000, or thereabouts, the carbon oxides formed are substantially carbon monoxide. As the temperature is increased in the presence of steam, the yield of hydrocarbons progressively decreases and the yield of carbon oxides and hydrogen increases. In the event that it is desired to produce carbon monoxide-hydrogen mixtures with relatively low concentrations or carbon dioxide and hydrocarbons, the temperature should be in the upper portion of the range described. 7

It is also contemplated that substantial amounts of methane and steam can be reacted in the presence of' the hot solids in the decomposing zone. The reaction is endothermic and proceeds rapidly to about 95% completion at a temperature between about 2000 and 2200 F. Oxygen can be supplied, the endoand exothermic reactions ofisetting each other to some extent.

In the event that it is desired to recover the liquid hydrocarbons derivable from coal and also to make high yields of carbon monoxide and hydrogen when coked,'I may eifect the decomposition in two stages so as to recover the hydrocarbon values separately; withdrawing from one the hydrocarbon values comprising liquefiable hydrocarbons and from the other the hydrocarbon values comprising carbon monoxide and hydrogen. In the hydrocarbon-recovering decomposition zone, an inert gas should be used to maintain the dense turbulent phase, and in the carbon monoxide-hydrogen producing decomposition zone steam is supplied for maintaining the dense turbulent phase and for reaction with carbon to produce carbon monoxide and hydrogen.

. The hydrocarbon-recovering decomposition zone is preferably operated in the lower portion of the temperature range described, for example, in the range of 1000 to 1500 F., while the decomposition zone used to produce carbon monoxide and hydrogen ordinarily will be operated in the higher portion of the range described, namely 1500 F. or higher, for example 2000 F. The optimum combination of temperatures for these two zones will depend upon the nature of the carbonaceous solids charged to my process, and upon the relative value of the two primary product streams. Both of these conversion zones will normally be endothermic, and the heat for carrying out these reactions will be supplied as sensible in the solids supplied from the heater. Hydrocarbon values recovered as carbon monoxide-hydrogen mixtures possess considerable value as a charging stock for the synethesis of aliphatic hydrocarbons. The relative ratio of oxidizing fluids supplied and carbon consumed in the decomposing zone will affeet the ratio of carbon monoxide and hydrogen produced and may be varied to give the ratio required for synthesis.

Figure 2 illustrates by diagram another embodiment of. my invention wherein the coke is handled in three contacting zones including a heating zone and two decomposing zones preferably at different temperature levels. Powdered coal, coke, lignite, peat, oil sands, or the like is supplied to the decomposer or coker 40 by any suitable means including direct injection into the dense turbulent phase within the coking zone or by a carrier gas as illustrated. The finely divided raw solids are introduced for example by line 4! which may comprise a standpipe and metering valve similar to those described in connection with Figure 1. The finely divided solids are picked up in a carrier gas in line 42 and introduced into coker 40. A quantity of powdered incandescent solids is withdrawn by line 43 from the decomposer or generator 44 and dispersed in a carrier gas in line 45. To obtain the maximum recovery of hydrocarbon values as liqueiiable hydrocarbons, the carrier gas should be inert or substantially unreactive with the solids. Streams of hot solids and raw solids separately dispersed are introduced into the recovery chamber or decomposer 40 through partition 46 into a dense turbulent suspended solids phase within the coking zone 40. The partition 46 comprises a screen, perforated plate, grid or the like. The baflie 41 avoids commingling raw solids with the hot solids except in the dense turbulent suspended phase proper of the contacting zone 40. The chamber 40 is of such size and shape as to permit a major amount of finely divided solids to accumulate therein in the dense turbulent solids phase above partition 46. Upward gas velocity of the order of between about 1 and 3 feet, for example, 2 feet per second, can be used to maintain the dense turbulent solids phase. Higher velocities in the case of larger particles and/ or greater density are contemplated.

' Hydrocarbon values evolved from the solids are continuously separated from the solids within chamber 40. Cyclone separator 54 can be provided to remove residual solids from the gases and vapors which are removed by line 65. The coked solids are withdrawn downwardly from the coker zone 40 by standpipe 48 and a valve can be provided in this line to control the flow of the powdered solids into the transfer line 49. A suitable carrier gas in line 49 may comprise the flue gases from the heating zone 50. The carrier gas supplied to transfer lines 42 and 45 is an inert gas such as tail gas from the recovery system of the decomposer 40. In somecases steam can be used.

Oxygen-containing gas. which can be air, is introduced by line 5| into line 49 and the combined stream introduced into the heating chamber 50 by conduit 52 through partition 53, similar to partition 46, above which a dense turbulent suspended phase is maintained. Within the heating zone 50 the carbonaceous material is burned at a temperature of between about 1800 and about 2500 F. The bulk of the incandescent solids is continuously separated from flue gases within the upper part of the chamber 50, the gases being removed overhead by conduit 55 and being sent to the stacks or used as a carrier gas as described hereinabove. One or more stages of cyclone separator 54 may be used. ,When it is desired to produce coke, the net production of coke may be withdrawn with the flue gases and separated by suitable means outside of the heating zone .48, in that event cyclone separators probably will not be used. A portion of the solids from decomposer 44 can be recycled by

lines

43a and 49 to the heater 50.

Incandescent solids are withdrawn from chamber 50 by standpipe 5B and dispersed in a relative large quantity of steam flowing-in line 51 and the mixture is introduced by conduit 58 and dispersed in a dense turbulent suspended phase above screen or partition 59 in the decomposer 44.

A preliminary distributor plate usually of lower pressure drop than partition 59 can be provided below distributor ring 63. The temperature within the chamber 44 is maintained at between about 1500 and 2000 F. by supplying incandescent solids thereto. At this temperature steam and -with efiluent in line 29 of Figure 1.

is endothermic and the cooled solids are withdrawn from the dense turbulent phase by conduit 43 and transferred by line 45 into the coker 40 as described above wherein the residual sensible heat is used to efiect the recovery of volatiles from the solids which comprise the raw solids feed to the system. If desired, methane or natural gas can be supplied to the generator 44, for example by line 62, wherein methane, steam and carbon react to produce additional amounts of hydrogen and carbon oxide. solids can be introduced by line lla particularly when it is desired to add reactant carbon to decomposer 44. It is also contemplated that oxygen can be introduced into the generator, for example by line 63, to react with hydrocarbons and/ or carbon to add heat and produce additional quantities of gases. Thus methane-steam, oxygen-carbon or oxygen-methane and water-carbon reactions cooperate to maintain the desired temperature level and the desired hydrogen to carbon monoxide ratios.

In some instances, for example when oil sands carbonaceous are being treated in the system, the solids can be withdrawn from the system by line 61 or 68. However, since this material will be at a relatively high temperature level, it may be contacted with additional quantities of steam or water to abstract heat directly and the eiiluent from the contacting supplied either to the generator zone 44 or to the coking zone 40. Coarse ash particles likewise can be withdrawn by line 61 or 68.

In general, the operation of the heating zone 48 and the decomposing zone 49 is similar to that described in connection with chambers 15 and II of Figure 1. The intermediate zone provided by decomposer 44 makes it possible, however, to recover hydrocarbon values as H2-CO mixtures under optimum conditions of temperature. The chambers each can be constructed of firebrick and will require very little structural steel bracing. The conduits may be constructed of ceramic tile and the like. It will be understood of course that metal vessels may be employed. The efliuent from the generator 44 may be recovered separately by line 60 or it may be combined by line 66 with the efiiuent from the coking zone 40 in line 65 and processed in a manner similar to that described in connection Cyclone separators are illustrated within each of the contacting chambers for returning the separated solids to the dense turbulent solids phase wi' hin each zone. These solids can be recovered irom one zone and introduced into another. The separators in one or more zones can, however, be

, omitted entirely.

Figure 3 illustrates another embodiment of my invention and is described in connection with the processing of shale or oil sands. A vertical cylindrical chamber I0 is provided with internal cylindrical bafile II defining an internal dense turbulent phase decomposing or reaction zone I2 and an external turbulent dense phase combustion zone I3. Both the tower and bailie can be constructed wholly or in part of brick and the like. The outer shell II] can be separated at I09 and sleeve 99 can be provided to cooperate with ballie H. Raw shale from shale hopper I4 is introduced by conduit I6 into milling zone I5. Valve II can be used for metering the shale, coal, sand, lignite, etc. The conduit I6 can be aerated by means of an aerating fluid introduced by line 18. When the raw solids are already finely divided, the milling zone I5 can be by passed. The finely divided solids are introduced into zone 12 by line I02. This can be accomplished by conduit I9 and steam line in a manner similar to that described in connection with Figure 1. Alternatively the raw solids can be carried by line Bl into an elevated separator 82 and the separated powdered shale or other finely divided solids introduced by dip leg 83 into the dense turbulent phase maintained within forty-two. In any event, the raw solids are denuded of the vaporizable hydrocarbons by contact with the hot residual solids main tained in zone I2. The vaporous eiiiuent from zone I2 within the baffle II comprises predominantly hydrocarbons recovered from the oil shale, water vapor, decomposition products, and finely divided denuded shale which was not separated out within the zone I2. The efiiuent is carried by line 84 into separator 85 wherein tar and solid particles are separated. A portion of separated material comprising tar can be recycled to the stripper 85 by line 86 and cooler 81, but the net tar production is withdrawn by pump 88 and line 89 and can be returned to the decomposing zone I2. The separated gases can be sent by overhead line 99 to condensing or fractionating equipment or directly to hydrocarbon conversion processes depending upon their composition. As described above, the nature of the effluent depends at least in part upon the temperature maintained within the decomposing zone.

The dense turbulent solids have a net downward movement through zone 12 and flow through the lower ports 9| in a bafiie or wall II into the dense turbulent combustion zone I3. The residual solids maintained in the dense turbulent phase are heated by the combustion of the hydrocarbonaceous material in the denuded solids and have an upward flow through the combustion zone 13. Air is introduced into the combustion zone I3 by line 92 and distributor 93. The velocity of the gases and the degree of oxidation may be independently controlled by introducing inert gas with air. The hot solids fiow through the upper port 94 in the bafiie Ii into the decomposing zone to complete the cycle. The coke or completely spent shale, sand, etc., is withdrawn by valve 95 and line 99. Likewise the spent solids or the coke can be withdrawn from zone I2. The direction of circulation of solids between the two zones may be the reverse.

The hot flue gases recovered overhead from the combustion zone I3 by line 98 pass through the economizer or waste heat boiler 91 and then may be introduced into the solids hopper III to dry and/or preheat the solids therein. In some instances it may be desirable to contact the oil sand, crushed shale, or coal with a combined stream of the flue gases and residual solids, i. e. the velocity of air or air and diluent in zone I3 is sufiicient to effect carry-over of at least part of the solids. Alternatively the flue gases and/or the residual shale can be used to preheat the powdered shale being introduced into the decomposing zone I2. Also the steam produced by steam boiler 91 can be the source of the steam in which the solids are dispersed in lines I9, 80, or 8|.

In all of the systems herein described, and particularly in the burning zones, I may employ stage-countercurrent contacting. In Figure l, for example, the denuded solids leaving the base of chamber II may be conveyed by carrier gas,

- 13 such as air or steam, to "the top of a modified form of heater chamber and either introduced directly thereto or introduced thereto by equipment similar to elements 8l-83 of Figure 3.

By providing perforated plates at spaced levels in the heater with staggered downcomer conduits associated-therewith and introducing the bulk of the air of combustion gas at a point near the base, the powdered solids may pass from stage to stage downwardly substantially countercurrent to the upfiowing air stream so that the oxygen of the air stream may be more effectively utilized, the off-gas from the lower zones will preheat the solids coming down from the upper zones and the zone at the base of the heater will be at the highest temperature and hence most suitable for cycling back to zone II. In such a system the solids are maintained in fluidized dense turbulentsuspended phase above each perforated plate or grid and likewise maintained in fluidized condition in their flow from the dense phase above each grid to the subadjacent phase below said grid. By this or equivalent means a countercurrent heating or treating effect' may be obtained in the burning zone.

Such staging for effecting countercurrent treating may also be employed in the decomposition zone or zones. Such countercurrent staging is particularly desirable where the decomposer is employed for producing carbon monoxide-hydrogen mixtures. By providing perforated plates at spaced levels in chamber ll of Figure 1 or decomposer 44 of Figure 2, each of said perforated plates being associated with one or more downcomer conduits (analogous to downcomer 43 associated with perforated plate 59 of Figure 2), and introducing the hot solids from the heater at the top stage of the decomposer while introducing steam, methane, etc. at the base of the bottom stage therein, the finely divided solids may be retained above each plate as a suspended dense turbulent phase and pass downwardly from dense phase to dense phase through the downcomers while the introduced steam, methane, etc. and conversion products are passing upwardly from stage to stage through the perforated plates thereby maintaining the solids in each stage in suspended turbulent dense phase condition. The temperature in the lowermost zone may in this case be too low for complete conversion so that the gases which pass upwardly therefrom will contain substantial amounts of carbon dioxide and steam. The temperature in the top stage, however, is sufiiciently high to complete the conversion and to insure that substantially all of the carbon dioxide is converted to carbon monoxide before the gases leave the top of the decomposer. By thus employing countercurrent staging in the decomposer the heating zone may be operated at lower temperatures than would be possible with a single stage decomposer and at the same time products may be obtained containing a minimum amount of carbon dioxide. By employing countercurrent staging in decomposer 40 I may effect distillation in the lowermost zone and conversion of distilled hydrocarbons into morevaluab'le products in the upper zone or zones.

This is a continuation-in-part of my copending application S.N. 483,166, filed April 15, 1943, now abandoned. Certain subject matter disclosed herein is claimed in U. S. Letters Patent No. 2,482,187.

It is-apparent from the above description that I have attained the objects of my invention in providing the novel process and apparatus for the recovery of hydrocarbon values from naturally occurring carbonaceous materials as hydrocarbons or'as a mixture of hydrogen and. carbon monoxide. Other modifications of my method and apparatus described herein can be made by those skilled in the art without departing from the spirit of my invention. Therefore, although I have described particular embodiments of my invention in more or less detail, it is to be understood that the invention is not limited thereto but is defined by the appended claims.

I claim:

1. The process of producing carbon monoxide and hydrogen and recovering hydrocarbons which comprises maintaining a body of finely divided carbonaceous solids within a first zone in a dense turbulent solids phase, maintaining said body at a high temperature by introducing hot solids into said first zone, reacting water vapor with the carbonaceous solids whereby carbon monoxide and hydrogen are produced, continuously separating gaseous products and solids, separately withdrawing incandescent solids from the dense turbulent solids phase, introducing the withdrawn incandescent solids into a second contacting zone in an amount sufiicient to all heat required therein, introducing raw finely divided carbonaceous solids into said second contacting zone, maintaining the finely divided solids within said second zone in a dense turbulent solids phase continuously separating gases and solids within said contacting zone, separately withdrawing solids from said second zone, transferring the withdrawn solids to a third contacting zone, supplying an oxygencontaining gas to said third zone and passing it through the zone at a rate sufficient to maintain a dense turbulent solids phase therein, maintaining the temperature of the solids within said zone at a high level by burning a portion of the carbonaceous solids with said oxygen-containing gas, withdrawing a portion of the hot carbonaceous solids from the dense turbulent suspended phase, and supplying at least a part of said withdrawn solids to the first zone.

2. The process of producing carbon monoxide, hydrogen and vaporous hydrocarbons which comprises maintaining a body of hot finely divided carbonaceous solids within a first contacting zone in a dense turbulent solids phase, maintaining said body at a high temperature by introducing hot carbonaceous solids into said first zone, introducing raw finely divided carbonaceous solids into said first contacting zone, contacting the body of carbonaceous solids within the first contacting zone with water vapor whereby carbon monoxide and hydrogen are produced, continuously separating gasiform products and solids, separately withdrawing incandescent solids from the dense turbulent solids phase within said first contacting zone, introducing a portion of the withdrawn incandescent solids into a second contacting zone and another portion into a third contacting zone, supplying an oxygen-containing gas to said second zone and passing it upwardly through the zone at a rate sufficient to maintain a dense turbulent solids phase therein, maintaining the temperature of the solids phase at a high level by conducting an exothermic reaction within said second zone involving said oxygencontaining gas, withdrawing the hot residual solids from the dense turbulent suspended phase within the second zone, supplying at least part of said withdrawn solids to said first contacting zone, supplying raw solids to said third contacting zone, passing a gasiform fluid upwardly through said third contacting zone at a rate surficient to maintain a dense turbulet solids phase therein, supplying as sensible heat in the incandescent solids introduced into the third zone all of the heat required for obtaining vaporous hydrocarbons from raw solids introduced thereto, continuously separating said vaporous hydrocarbon products and solids, separately withdrawing solids from said third zone and transferring the withdrawn solids to the second contacting zone.

3. The process for recovering vaporizable products from finely divided carbonaceous solids and for producing mixtures of hydrogen and carbon monoxide which process comprises introducing incandescent finely divided carbonaceous solids into a confined contacting zone, introducing a gas comprising steam into said zone and passing said gas upwardly through said zone at a rate sutficient to maintain said solids in suspended turbulent dense phase condition, maintaining said zone under conditions for efiecting conversion of a substantial amount of said steam with carbon in the carbonaceous solids for producing hydrogen and carbon monoxide, continuously separating reaction products from solids in the upper part of said zone and withdrawing gasiform reaction products from the upper part of said zone, separately removing a portion of the incandescent solids from the dense turbulent suspended phase at a point below the upper level thereof, transferring at least a portion of said removed incandescent solids to a coking zone, introducing raw finely divided carbonaceous solids into said coking zone, maintaining the solids within the coking zone in a fluidized dense turbulent phase by passing a gasiform fluid upwardly therethrough, supplying all of the heat required in the coking zone by the sensible heat in incandescent solids introduced thereto from the contacting zone continuously separating gasiform products from solids in the upper part of said coking zone and withdrawing said gasiform products from the upper part of said coking zone, separately withdrawing coked solids from the dense phase in said coking zone below the upper level thereof, introducing the coked solids thus removed into a heating zone, introducing a gas conprising free oxygen at a low point in said heating zone and passing it upwardly therethrough at a rate sufiicient to maintain the solids in dense turbulent suspended phase in said heating zone and for heating said solids in said zone to incandescence, separating combustion products from solids in the upper part of the heating zone and removing, said combustion products, continuously removing a portion of the incandescent solids from said heating zone at a point below the dense phase level therein and transferring said incandescentsolids to said contacting zone. I

4. The process of claim 3 which includes the further step of supplying methane along with steam to said contacting zone.

5. The process of claim 4 which includes the step of introducing free oxygen to said contacting zone for effecting partial combustion of methane introduced with said steam.

6. The method of producing from carbonaceous solids both vaporizable hydrocarbons and a gas suitable for the synthesis of hydrocarbons which method comprises introducing finely divided raw carbonaceous solids into a coking zone, simultaneously introducing into said coking zone, from a decomposing zone as hereinafter set forth, finely divided carbonaceous solids which are at a temperature upwards of 1500 F., passing a nonoxidizing gas upwardly through said coking zone at a rate suflicient to maintain the combined solids therein in suspended turbulent dense phase condition at a temperature below about 1500" F. but sufficiently high to effect at least partial carbonization of raw solids and production there- 'from of vaporizable hydrocarbons, separating said hydrocarbons from solids in the upper part oi! said coking zone and removing and recovering at least a portion of said separated hydrocarbons, separately removing solids in dense fluidized condition from a point below the level of the dense phase in 'the coking zone and introducing the withdrawn solids into a heating zone, introducing an oxidizing gas comprising free oxygen at the base of said heating 'zone and passing said gas upwardly in said zone at a rate sufflcient to maintain the solids therein a suspended turbulent dense phase condition and for heating said solids to incandescence in said heating zone by partial combustion of carbonaceous material, separating combustion gases from solids in the upper part of the heating zone and withdrawing said gases, separately withdrawing incandescent solids from a point below the dense phase level in the heating zone while retaining the solids in dense phase condition and introducing at least a part of said withdrawn solids into a decomposing zone, passing a gas comprising steam upwardly in said decomposing zone at a rate to maintain the solids therein in suspended turbulent dense phase condition and at a temperature above 1500 F. suificient to effect production of carbon monoxide and hydrogen, separating carbon monoxide and hydrogen from solids in the upper part of the decomposing zone and withdrawing it from said zone, separately withdrawing incandescent solids from a point below the level of the dense phase in the decomposing zone and introducing at least a portion of said separated incandescent solids into said coking zone in an amount sufficient to supply all of the heat required for effecting coking therein.

7. The method of claim 6 which includes the step of returning to the heating zone a part of the solids withdrawn ,from the decomposing zone.

8. The method of claim 6 which includes the step of introducing a hydrocarbon gas in addition to the steam introduced into the decomposing zone.

9. The method of claim 6 which includes the step of introducing both a hydrocarbon gas and oxygen in addition to steam into the decomposing zone.

MAURICE H. ARVESON.

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

UNITED STATES PATENTS Number Name Date 1,687,118 Winkler Oct. 9, 1928 1,840,649 Winkler et al Jan. 12, 1932 1,984,380 Odell Dec. 18, 1934 2,253,486 Belchetz Aug. 19, 1941 2,341,193 Scheineman Feb. 8, 1944 2,387,309 Sweeney Oct. 23, 1945 2,482,187 Johnson Sept. 20, 1949 FOREIGN PATENTS Number Country Date 564,870 Germany Nov. 24, 1932 632,466 France Oct. 10, 1927 Certificate of Correction Patent No. 2,560,403 July 10, 1951 MAURICE H. ARVESON It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 14:, line 26, after to insert supply; column 15, line 2, for turbulet read turbulent; line 47, for conprising read compm'sing; column 16, line 18, for therein a read therein in and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Office. Signed and sealed this 25th day of September, A. D. 1951.

[SEAL] THOMAS F. MURPHY,

Assistant Commissioner of Patents.

Claims

1. THE PROCESS OF PRODUCING CARBON MONOXIDE AND HYDROGEN AND RECOVERING HYDROCARBONS WHICH COMPRISES MAINTAINING A BODY OF FINELY DIVIDED CARBONACEOUS SOLIDS WITHIN A FIRST ZONE IN A DENSE TURBULENT SOLIDS PHASE, MAINTAINING SAID BODY AT A HIGH TEMPERATURE BY INTRODUCING HOT SOLIDS INTO SAID FIRST ZONE, REACTING WATER VAPOR WITH THE CARBONACEOUS SOLIDS WHEREBY CARBON MONOXIDE AND HYDROGEN ARE PRODUCED, CONTINUOUSLY SEPARATING GASEOUS PRODUCTS AND SOLIDS, SEPARATELY WITHDRAWING INCANDESCENT SOLIDS FROM THE DENSE TURBULENT SOLIDS PHASE, INTRODUCING THE WITHDRAWN INCANDESCENT SOLIDS INTO A SECOND CONTACTING ZONE IN AN AMOUNT SUFFICIENT TO ALL HEAT REQUIRES THEREIN INTRODUCING RAW FINELY DIVIDED CARBONACEOUS SOLIDS INTO SAID SECOND CONTACTING ZONE, MAINTAINING THE FINELY DIVIDED SOLIDS WITHIN SAID SECOND ZONE IN A DENSE TURBULENT SOLIDS PHASE CONTINUOUSLY SEPARATING GASES AND SOLIDS WITHIN SAID CONTACTING ZONE, SEPARATELY WITHDRAWING SOLIDS FROM SAID SECOND ZONE, TRANSFERRING THE WITHDRAWN SOLIDS TO A THIRD CONTACTING ZONE, SUPPLYING AN OXYGENCONTAINING GAS TO SAID THIRD ZONE AND PASSING IT THROUGH THE ZONE AT A RATE SUFFICIENT TO MAINTAIN A DENSE TURBULENT SOLIDS PHASE THEREIN, MAINTAINING THE TEMPERATURE OF THE SOLIDS WITHIN SAID ZONE AT A HIGHLY LEVEL BY BURNING A PORTION OF THE CARBONACEOU SOLIDS WITH SAID OXYGEN-CONTAINING GAS, WITHDRAWING A PORTION OF THE HOT CARBONACEOUS SOLIDS FROM THE DENSE TURBULENT SUSPENDED PHASE, AND SUPPLYING AT LEAST A PART OF SAID WITHDRAWN SOLIDS TO THE FIRST ZONE.