US2539466A - Process for carrying out endothermic chemical reactions - Google Patents

Description

Jan.' so, 1951 Y v. F. PARRY 2,539,466 PRocEss Foa CARRYING ou'r Ennommc Cl-IEMICAL REACTIONS originall'Fied Aprim 2o. 1945'l '7 Sheets-Sheet 1 FIG! INVENTOR VER F. PARRY Jan. 30, 1951 v. F. PARRY PROCESS FOR CARRYING OUT ENOOTHERMIC CHEMICAL REACTIONS '7 Sheets-Sheet 2 Original vFiled April 20. 1945 INVENTOR VERNON PARRY Jan. 3Q? 1951 v. F. PARRY 2,539,466

PROCESS FOR CARRYING OUT ENDOTHERMIC CHEMICAL REACTIONS Original Filed April 20, 1945 '7 Sheets-Sheet 5 VERNO F. PARRY By ATT RNEY Jan. 30, 1951 v. F. PARRY 2,539,465

PROCESS FOR CARRYING OUT ENDOTHERMIC v CHEMICAL REACTIONS Original Filed April 20, 1945 '7 Sheets-Sheet 4 INVENTOR VERNON.

ATRNEY Jan. 30, 1951 v. F. PARRY 2,539,466

PROCESS FOR CARRYING OUT ENDOTHERMIC CHEMICAL REACTIONS Original Filed April 20, 1945 7 Sheets-Sheet 5 FIG.|O

ATT RNEY Jan. 30,4 1951 v. F. PARRY 2,539,466

PROCESS FoR CARRYING ouT ENDCTRERMIC CHEMICAL REACTIONS Original Filed April 20, 1945 '7 Sheets-Sheet 6 FIGS ATTORNEY Jan. 30, 1951 v. F. PARRY 2,539,466

PROCESS FOR CARRYING OUI` ENDOTHERMIC CHEMICAL REACTIONS Original Filed April 20. 1945 7 Sheets-Sheet '7 20F 2O E INVENTOR FI I VERNON F. PARRY Wwf AT RNEY atented jan. 3,0, 195i PRGCESS FOR CARRYNG @UT ENDU- THERMIC CHEMICAL REACTIONS Vernon F. Parry, Golden, Colo.

Original' application April V20, 1945, Serial N0. 589,450. Divided and this application (Botober 7, 1946, Serial No. 701,632

(Granted under the act of March 3, 1883, as amended April 30, 1928;vv 370 0. G. '757)A 1 Claim.

The invention described herein may be manufactured and used by or for the Government of the United States for governmental purposes without the payment to me of any royalty thereon in accordance with the provisions of the act of April 30, 1928 (oh. 460, 45 Stat. L. 467).

This invention relates to chemical reaction apparatus and methods, and more particularly to suitable methods and devices for carrying out endothermic chemical reactions involving solid and gaseous or vaporous materials. Still more particularly, this invention relates to processes for the production of synthesis gas and fuel gas from subbituminous coal or other non-cang or non-agglomerating carbonaceous materials in a vertically ranging externally heated annular retort.`

Heretofore in the fuel converting art large reaction vessels requiring heat transfer at high temperatures, have been made of refractory fire brick and heated by gas or oil-red ovens. Such refractory rebrick settings have W thermal conductivity and they transmit heat relatively slowly compared with the heat transfer which may be transmitted through metals. In the heating of metallic reaction vessels, troubles are usually encountered from local overheating which causes excessive corrosion, unequal expansion, and short useful life of the metal. It has novv been. found that by employing the special heating system herein described, alloy reaction vessels can be heated safely and uniformly in controlled atmosphere, and their useful life extended through a long period of continuous operation. l

' Heretofore, in the production of water gas, synthesis gas, and the like,A it has been necessary to employ batch operation, alternately to blow steam through the incandescent fuel bed to yield such gas. It is not feasible to use low rank fuels such as lignite or subbituminous coal in machines employing intermittent alternating blasts of air and steam, because of decrepitation of the fuel under such treatment which causes excessive back pressure and abnormal losses in the form of ne dust. Therefore the low-rank fuels have not been used for making Water gas, but it has now been found that in accordance with this invention, lignite, subbituminous coal, or other non-coking fuels can be gasii'led successfully, and the desired water gas reactions, as Well as other chemical endothermic vreactions involving solids and gaseous materials, can be carried out in a continuous manner at higher efliciencies than can be obtained by other processes.

In the United States the principal raw materials now usedv for manufacture of Water gas are the higher rank bituminous coals used either in their natural state or converted to hard coke by Well known carbonization processes. These fuels are not reactive and high temperatures are necessary when gasifying them by reaction with steam or other gases. yIt is not feasible to conduct the so called Water gas reactions on high rank fuels in metal vessels because of rapid deterioration of the vessels caused by the high temperature of the reaction. On 'the other hand the low-rank fuels, such as subbituminous coal and lignite, have relatively high reactivity, en`

doive-d by nature, which permits the various water gas reactions to be conducted at relatively loiv temperatures within a range permitting use of alloy steel reaction vessels. For example the high rank fuels must be heated to temperatures in excess of 1800 degrees F. in order to make Water gas by reaction with steam, but the 10W rank fuels start to react with Water at temperatures as low as 1200 degrees F., and in the temperature range 1550 to 1.850 degrees F. the rate of reaction is very fast, in fact fast enough to justify commercial operation. Thus it is feasible to make industrial Water gas from low-rank fuels in Vexternally heated metallic retorts because of the natural property of high reactivity possessed by these fuels, and this invention is designed to take advantage of that property.

This invention accordingly has for its object the provision of a method and apparatus for continuously carrying out endothermic chemical reactions involving a solid material having gas forming and liqueable constituents and a gaseous substance. Another object is to provide a suitable method and apparatus for the continuous production of synthesis gas from lignite or other non-caking carbonaceous material. Another object is the continuous production of a gasy containing a controlled ratio of hydrogen to carbon monoxide from non-caking carbonaceous materials, While producing a maximum quantity of condensible oil or tar from the carbonaceous materials with gasication of the carbon residue. Further objects relate to the production of relatively smokeless fuels from non-caking coals; to the reduction of metallic ores such as those of iron, magnesium, Zinc, and similar ores; and to suitable apparatus for carrying out the foregoing reactions. will be apparent or will appear as the ensuing description proceeds.

' In accordance with this invention an endother- Other objects .of the invention` 2,539,466 g t f 3 mic chemical reaction process involving a solid material and a gaseous or vaporous substance is carried out by passing said material through a stage heated annular reaction Zone while withdrawing gaseous reaction products from a heat exchange zone enveloped by said reaction zone. It has been found that stage heated annular reaction zones provide superior means for carrying out endothermic chemical reactions between solids and gases of vapors, since heat can "be,

supplied to the reactants with very high efciency in heat resisting metallic vessels, and by utilizing the interior of an annular reaction zone as a heat exchange zone for withdrawing gaseous or vaporous products, increased eiciency can be obtained.

This invention also contemplates carrying out an endothermic chemical reaction involvingl gaseous and solid materials by passing said materials concurrently downward through an externally-heated vertically ranging elongated annular reaction Zone, withdrawing gaseous products from said reaction zone near the zone of maximum reaction temperature and discharging said gaseous products upwardly while maintaining them in indirect heat exchange relation to said descending reactants, then discharging spent solids from a lower annular reaction zone counter-currently to ascending gases, while maintaining said lower annular reaction zone in indirect heat exchange relation with incoming gaseous or vaporous reactants. By providing two annular reaction Zones as described, the entering solid and gaseous materials are preheated while recovering heat from exhausted gaseous products, and after attaining a maximum reaction temperature, the solid reactants are further passed in heat exchange relation to'additional incoming gaseous or vaporous reactants or carrier gases as the case may be.

In the following description, it should be understood that the term gaseous includes materials which are vapors at the temperatures encountered, such as for example, steam, oil vapors, and similar materials. Furthermore the terms non-caking, non-agglomerating, or non-coking are associated with and define a material that does not swell or fuse to destroy its abilityto move by gravity as a relatively free-flowing material. In describing the method of this invention, the description will be directed principally to the gasification of lignite or subbituminous coal, but the invention is not limited thereto as will be apparent.

The reader will appreciate the improvement in the art and efficiency of gasification of fuel made possible by this invention when he considers the brief comparison cited herewith:

In present commercial processes for the manufacture of synthesis gas from coke, as practiced by large War II industries, one ton of highrank bituminous coking coal of 13,500 B. t. u. per pound, after coking in a coke oven, will make about 35,000 cubic feet of synthesis gas. The conversion requires 2 steps; a. Coking in the coke oven by intermittent operation; and, b. Gasication in a water gas machine by intermittent blasting with air and steam. In the continuous process comprising this invention one ton of natural subbituminous coal containing about 22 percent water and having a 'heating value of only 9,300 B. t. u. per pound, is gasied continuously to produce 45,000 cubic feet of net synthesis gas in a single stage process that operates automatically.

In order to accomplish the, high conversion '4 efficiency, ranging from to 75 percent or higher, the heat saving devices and the countercurrent heat exchange principles outlined herein have been invented.

In the accompanying drawings:

Figure 1 is a view partly in section and partly diagrammatic, showing a vertically ranging annular reaction apparatus having an external heating chamber and a reouperator associated therewith.

Figure 2 is a view, partly in section and partly diagrammatic, showing a vertically ranging annular reaction apparatus similar to Figure l and showing also a suitable arrangement for feeding incoming solids; removing, cooling, and scrubbing evolved gases and vapors; and recycling products of combustion.

Figure 3 is a view, partly in section and partly diagrammatic, showing a generating unit and the recycling apparatus of Figure 2 on a somewhat enlarged scale.

'Figure 4 isa view,lp'a`rtly in section and partly diagrammatic ofthe device of VFigures 1 and il suitably Amodified -by the addition of heat ex'- change means for imparting heat to incoming solids from the spent products ofr combustion, and also providing a different arrangement of annular domesin the reaction Zone particularly adaptedlto the-production of oil and xed gases from oil-bearing shales, 'or' low-temperature tar and Xed gases from-rion-coking coals wherein secondary Y decomposition of distillation vproducts isrepressed. The gurealso shows an arrangement of-afbubble tower-for fractional condensation of vapors.

-Figure 5 is Aany enlarged sectional view of*l a further alternative arrangement Afor f the annular reaction apparatus of Figures 1, 2, 3 and 4 provided with asuppleine'ntaryf'heat exchanger'v in the central-'portion of the upper heat' exchange zone whereby gases admitted to thelower heat exchangezone take up heat from the gaseous products of reaction.

Figure `6 is `an enlarged view, partly in section and partly diagrammatic, of the annular portion ofthe V"apparatus of Figure l providing means for recirculating a portion of the fixed gases' t0 the lOWeI "2431111.1115- Fgure'? fis an enlarged detailed sectional view,

partly diagrammatic,v showing' a modification of` thesuperposed annular reaction apparatus o f Figure 5 adapted tothe" successive distillation of v'c`ilatiles'-aiidV gasification of 'residual carbon vin non-agglomerating lcarbonaoeous materials,v such as' lignite, subbituminous coal,'and oil shales.

Figure 8 is an enlarged sectional View, partly diagrammatic, showing the annular reaction reaction device of Figure 3 having a suitablegar.-

rangement for introducing gas-oil or carburettiifig bustion chamber for preheating steam or fixed` gases introduced into the lower annulus.

.Figure 9a is a detailed section of the inlet pipe to the lower reaction zone showing a packing gland and collar.

Figure l0 is a sectional View", partly diagrammatic, of the lower part of the annular reaction vessel and furnace of Figure 4 having a central draft inlet for introduction of air and steam to gasify xed carbon and volatile matter in spent shale or carbonaceous material discharged from the heated reaction annulus, a transfer screw to remove spentmaterial and means for cooling the outgoing solids.

Figure a is an enlarged view of the central draft inlet showing an arrangement of ports and conical bafes providing for introduction of a gaseous reactant.

Figure 11 shows sectional views of the brickwork, gas firing ports, air ducts, and combustion chamber surrounding the annular vessel of Figures l, 2 and 3. In Figure lla the section yis drawn horizontally across the vessel at points C-C referred to in Figure 1. Figure 11b shows a section through DD and Figure llc is a section through EE of Figure l.

'Ihe following brief description explains a procedure for making gas from undried subbituminous coal by the method outlined in `this invention. Referring to Figure 3, freshly mined subbituminous coal containing about 22 percent mois,- ture is charged into the top of the apparatus and directed downwardly by gravity through annular preheating and reaction zones. Steam is mixed with the coal and reaction begins as the temperature increases. rIhe products of reaction are removed from the interior of the annular reaction zone and give up a substantial portion of their sensible heat to incoming reactants. Solid materials not combined with reactants in the upper zone are then directed downwardly where they contact cooling gases which transfer heat from the solids back toward the center 0f the'system, and the spent solids are discarded at a low temperature. Thus, heat for carrying out the gasication reactions is retained near the center of the system, and products leave at low temperature which insures high efficiency. In gasifying undried subbituminous coal, up to 95,000 gross cubic feet of water gas is obtained per ton of coal l.

treated. The spent residue contains only 2 to l0 percent of the carbon originally present in the raw coal charged. Part of the gas made may be directed back for heating the reaction Vessel or suitable producer gas may be generated from spent solids to supply heat for the reactions. The combustion Asystem is arranged to return heat to the high-temperature zone and to recover substantially all the heat from the evolved gases.

For a practical embodiment of the invention, and referring now to the drawings, an elongated vessel 56 which may be vertically mounted as shown, is provided near its upper end with a suitable device for feeding solid materials 1ater to be described, and is closed at its lower end by a suitable closure device forming a part of the supporting means for the vessel 56. As shown in Figures l, 2, 3 and 4, the closure device is an inverted conical annulus |36 or a flat circular cup as shown in Figure 9. The vessel 56 may have any desired cross-sectional form, but it is preferably made circular in order to simplify construction. Connecting the conical discharge annulus |36 and the vessel 56 is an expansion joint seal 55, which may be of the flanged or ring type. The conical annulus or flat circular cup 14 is supported by suitable adjustable resilient mounts 49 or 49a which may take the form of springs or hydraulic jacks (not shown) adapted to exert an upward pressure against the force of gravity and to main;-

tain any desired stress condition in the vessel 56;

Connected to the conical annulus |30 is a device for discharging spent solid material while maintaining a gas-tight seal. As shown in Figure 4, the device comprises a pair of o-ppositely rotating serrated cylinders or star feeders 48. Below the cylinders 48 is a butterfly valve |3'| for causing solids to be vented into a water-seal |16. The seal |16 is provided with a drag conveyor 50a. Alternatively, the discharging device as shown in Figure 2 may take the form of a rotary vapor sealing valve 48a of the paddle wheel type lin conjunction with a water-lled screw conveyor 50. A further modification of the discharging device, shown in Figure 9, may take the form of a at circular cup 14 supporting the vessel 56 having a revolving curved paddle scraper 63 to take solids from the periphery and to discharge them through the central duct 67 where they are fed to a screw conveyor 50 communicating with a gas producer 59. The hot carbonaceous solids are cooled by introduction of a cooling gas or liquid through cooling ports 16 in the conveyor 56. When water is used for cooling, an eiective gas seal for moderate pressures is obtained between the vessel 56 and the gas producel1 59. In operating this form of discharge, the scraper 63 is turned by vertical shaft 68 and pinion 69, which may operate at variable speed to adjust the rate of discharge suitably correlated with the driving pulley 88 for the conveyor 59. A further modification of the discharge device, shown in Figure l0, may take the form of a sloping screw conveyor 56 driven by a variable speed moto-r (not shown) attached to drive pulley 88. Dry material can be removed by this device at constant rate depending upon the speed of the screw 59 conveyor. Sealing is accomplished by introduction of cooling water in ports lil. The packing gland 'H which is similar to that shown in Figure 9a, can be adjusted to compensate for expansion of vessel 56.

For the purpose of defining an annular reaction zone while removing the formed gaseous products with concurrent internal heat exchange, there is aligned within the elongated vessel 56 a suitable heat exchange device 58 dening with the vessel 56 an annular reaction zone 33. As shown in Figure 2, such a device is an elongated cylindrical annulus 58, spaced away from and aligned with vessel 56. The annulus 58 is open at its lower end. Located within the reaction zone 33 are positioned a plurality of spaced temperature-responsive elements 9, I6, and I4 for indicating temperatures on recording devices (not shown), and

to aid in controlling reactions later to be described. Preferably, the temperature responsive elements 9, I6, Il, and I4 are supported on the heat exchange device 58. Surmounting the upper portion of the cylindrical annulus 58 is a vent pipe 4| for removing gaseous products from the heat exchange zone 40 within the cylindrical annulus 58.

Suitable means are provided for conducting evoived gases from the reaction zone 33 into the heat exchange zone 4D, as shown.

Suitable means for feeding solid materials, alone or admixed with liquid or gaseous substances, are provided near the upper end of the vessel 56. As shown in Figure 2, such means may comprise a conveyor or skip hoist (not shown) leading to a hopper 36. From the hopper 30 the solid feed material passes downwardly by gravity through vapor sealing cone valves 3| into a preheating zone inthe vessel 56 as shown in Figzama-46e 'by means ofzsuitable:.wheels'i'32. IOthenfsuitable means .for introducing: solidsecontinuously @into the.y top .-preheating Zone imay. be used.

` Uponf entering .the vessell 56::.af relatively 1large body. of incoming. solidi-materialsl is fheld `up "inthe preheatingy zoneizsgfdened -by thefvessel .56 and .the vent pipeill I wherebyzheat :istakenf-Luplby'athe solids from the evolvedrgasespassing in::indirect zcountercurrentheat exchange-relationship to-the solids,

. if desired,v suitable means .are Lprovided forad- .mitt'ingf gaseous or. vaporous :materials Lto :the

preheatingzzonefll. intheilfupperportion f the vesseli56. .'.Asishown .in Figures ..2 `and Sian .inlet pipe-38 is connectedftolan annularjack'et 39.1po-

'sitionedinz theV heat exchangezone: 60 surounding .'thevent pipe Ill whereby the.- hot 'gasesfissuing fincoming vapors. .The jacketl39 :isprovidedwith .suitable openings' near.' the lower portionlthereof Vor is merely. left open. at the bottomgasshownfso that. steam orrother gaseous reactant is `admixed in thepreheating zone. 8f3 .with-.the solid materials.

.The preheatingzone issuitablylagged Orotherwise. insulated .against heat lossesiby. av heat .in-

sulating layer; |33.

For many gchemical. reactions involving Y'solid and gaseousror vaporousreactants, it has been found that a :plurality of. internal heatexchange devices mounted in 'thecommon elongated vessel 56 provides a.. superior annular reaction apparatus, particularly wherefit.- is .desired to carry rout a multiplefstage reactioninvolving concurrentl treatment of solidsiandigases Iin a rstf annular reaction zone and countercurrent treatment of solids and gasesina' second-annularre action zone. -A suitable form .of. apparatus.- Iparticularly shown in Figures 1,52,` 3 and 4, comprises va-cylindrical annulus 58 occupyingtheupper :por-

tion ofthe elongated vessel 56Laligned .therein and surmounting, but spaced from a lower cylindrical annulus 35. Asshovvn, .the..lower cylin- .drical annuluse'isY capped bya'r conical closure I 34. The wall of the lower cylindricalfzannulus 36 Ydefines with the wall -ofathefelongated'lvessel 5S azsecond` or lowerY reaction.- zone3.351 inl-w-hich solids mayfreact with orevolvefgases-cr vapors. The bottoms of. both the annulusfand Ithe'annulusw38are open'. to permitxfreesgas passage. The lower portioniof annulusf andi-the' conical closurey I3Llr of the. annulus2B6dene=afthroat3 for vpermitting` escapefof ygases fromithe :reaction zones'33.:and;35 into heat'sexchange zonelllfl.

f Optionally; suitable. means fork measuring-the temperatures vprevalent inthe annular' reaction lzone 35 may ybev'provicledy and-as.shown,altem perature responsive :device I 4; may be suitably positioned to indicate .reaction temperatures. Where it is desiredfi'to introduce gases/.orvapor into the lower heatieXchange-zone |35 or into .the interior of thel'cylindricalaannulus;36, such gases or vapors may be suitably introduced by way of an inlet pipeIS'l. :.For. some reactions, such as gasification of charsfrom.non-cokiugz'coals, superheated steam .or.:.gases Amay. be '..introduced into the reaction zone'a as shown irrligure'Y 9, by passing the vaporsz through: apreheatingridevice 6IY located in the combustion'charnber-LZII. When operating inthis. manner'gases or vapors are introduced into inlet pipe.31 .and arefpreheated preferably ina ycoil orlannularja'cketl mounted on the Walls of combustionchamber 24, and are thencegpassed into'sthe vessel 56. y.ffAs shown in Figure aga, the inletl ppei.31,-*in:entering termediatecylindrical annulus ISB.

4the 'vesselz-SS ispa'ckedc-in1a2packingglandf I1If. by .i a" rammed.1packing I 18.

VAn I 1 alternative v arrangement of 'l apparatus to secure-'transferwof heat fromthe4 evolved 'gases and lvapors-in theiupper heat exchange zone-40 Vmay be! secured,m as. .more Yparticularlyshown y in Figure 5,' bypassingl the incoming gasesror vapors -goingl'into fthe lowerV heat exchange. zone uI-35 through an inlet pipe 62 communicating'with-a vsource of:-.Igaseous` reactants, and through-ia'.Y -heat .exchanger..64Lpositioned in the upper :heat-exchange zone40,..andlthence.into the lowerL cylindrical annulus 36.

. For some reaetions;.lparticularly the Yproduction 'of foil .from Y.oil .bearing fshales. or highvolatile -non-coking. coals,- it. may be desirable to recir- .culatefafportion.ofathe fixed gases evolved from the -upper heatexchange zone 451 intothe' lower Vheat.exchangei zone .I'35. 'As shownmoreLpa-r- .ticularly inFigure 6, this may .be .accomplished by passing the evolved gases or vapors throuf'gh a. suitablescondensing device.'v 66, .a recrculating ypipeISI, and aregulatingvalve ISI, `to return the -.-gases through-.theinlet rpipe 31. :ByLthis -means,f.a..large'.quantity of carrierffgascan rbe passed: through the. reaction vapparatus inridrect vcontact with the. solid reactants .to provide4 for more ".rapidtransfer ;of heat ..1 and removal fof evolved products as Well as. torepress' formation of flxedgases.

In vsome multiple-stage reactions,v for :example inthe: successive distillation Yand. gasication Iof `oil-bearing shales or; nonecoking coals, .an intermediate cylindricalannulus ISB as shown infliiglure 7 serves to' permitthe withdrawal of inter` `mediately-forrned gases or vapors. In Figure "7, the upper cylindrical annulus 58 and theslower cylindrical: annulus 36.- are 'shortened to provide space 'inI thejvesselrEEo` forza similarlyalignedi-in- Theintermediate annulus i381 (Figure 7) .is spaced apart from'- the Yvessel 56 toifdeine an intermediate reactionV Zone I55,. and-is open;at the bottoznand spacedfapartfrorn a lower conical closu-reslfl to form lauthroat 34-for collecting .evolved gases in the @intermediate :heatfexchange .zone i 59. CappingA the intermediate cylindrical. annulus 36 is a :conical closure? Iwhichis .connected to and;V provides. a .seat forJaVv vertical vent pipe -.I 5'! passing :upwardly through .the upper. heat .exchangezone :d0 .and thence. out tof the vessel 56.

. Associated i with the .elongatedvessel 55 zare Ynovel heating.;means'for supplying necessary endothermic .heatpfto .carry .out the reactions taking placez-Tini theannular reaction zones'- 33, 35; and |55. shown Figure 3, suchmeans may take the form .of '1.a combustion chamber having :an `outer casingf I39Jassociated1with arecuperator leavingl an outer-casing 1-I6-for lrecovering heat fromJcombustionwgases, anfexhaust'fan M35-a freshair duct 21 orL alternately I5,-and suitable adjustable means including a valve- |45 for -recirculating a= proportion of flue gases or' P. O.' C. (products Y.of combustion) to vthe combustion chamber'asa tempering medium forV controlling .flame temperatures .invii the lcombustion zonef 24 heatingithefvessel 56.

The combustion chamberrouter casing E39' (Figures 1,-"2, 3 and4) has a suitable basestructure I'II andbottom closure H0 mounted therein, embracinglthe vessel456 in aegas-tignt-sliding't The'ftop ofthecasing'! 39 has'a cap I D embracling. the upperportion lof the vessel 56 in*k gastightvsealing engagementtherewith. The casing I k39.y is providedv with*` an `insulating refractory llin- 'ducts |9.

ing 51 through which extend a series of tangential burner ports 20, 2|, and 22 shown in detail in Figure l1. The tangential burner ports 20, 2|, and 22 are mounted in the outer casing |39 at different levels and direct burning fuel into the Acombustion zone 24 around the vessel 56. A series of vertically ranging gas passage ducts I9 identified by ducts A, B, C, D, E, F, G, H, I, J, K and L of Figure lla are formed in the lining 51 and supply a preheated mixture of air and recirculated products of combustion (P. O. C.) to tangential burner ports 20, 2|, and 22. In Figures 11a and 1lb, an arrangement of the tangential burner ports at two levels is indicated. In Figure 11a which represents a cross section through baf- -ile 53 at C-C in Figure l, an arrangement of twelve vertical ducts I9 is indicated by clock-wise lettering from A to L. Such ducts are suitable for firing a medium sized combustion furnace. In a larger furnace a plurality of ducts would be provided to supply preheated air and products f combustion at different levels as the furnace increases in height, having about the same distribution at each level as that indicated in Figure 11b. Duets |51 may be of any suitable shape and size to provide for required gas-flow. Referring to Figure 3, the refractory insulating material 51 outlining the combusti-on zone 24 within the outer casing |39, is preferably made of light-weight insulating refractory key brick but suitable plastic insulating refractories that can be cast in place may be used. A gas passage manifold I1 is formed in the lining 51 near the upper end thereof and provides a common source of supply for the Each duct I9 has an adjustable gas metering valve I8 which may be manually controlled as shown. Preheated air and P. O. C. mixture is supplied to the manifold |1 from the recuperator by a horizontally ranging inlet duct |60 connecting the recuperator and the manifold In the combustion zone 24 (Figure 3) a flame guard 23 extends from the bottom closure |10 or from the top of the refractory bottom lining upwardly toward burner ports 2| and embraces the vessel 56 to protect it from excessive local heating. A horizontally ranging deflecting baffle 53 is located in the upper portion of the combustion zone 24 below a discharge flue 25 to cause combustion gases to travel completely around the vessel 56.

A flue 25 in the Icasing IBI connects the upper portion of the combustion zone 24 above the bafe 53 with the recuperator and serves to conduct combustion gases from the combustion zone 24 to vvvertically disposed in the casing |6 is a suitable tube bundle i66 supported by an upper tube sheet |61 and a lower tube sheet |68 (Figure 3). Suitable horizontal deflecting baies |42 are disposed vinside the casing 6 about the Vtube bundle |66 to provide for an elongated gas passage traveling about and through the tube bundle |66. The

' products of combustion issuing from the combustion zone 24 through the flue 25 enter the recuperator below the upper tube sheet |61 and pass downwardly about the tube bundle |66 (Figure L35- through a flue 26 after giving up their heat and 'I hey are removed from lthe recuperator are thence passed through an exhaust fan |43 into a stack juncture casing |69. A lower header |65 is formed in the lower portion of the casing I6 and is adapted to distribute incoming air and P. O. C. through the interior of the tube bundle |66. An upper header |64 is formed by the upper tube sheet |61 and passes fresh air and recirculated products of combustion into the inlet duct |60. The stack juncture casing |69, upon which is mounted the stack 52, is provided with a stack valve |45. The casing |69 also has a valve |46 through which a controlled proportion of products of combustion can be recirculated to the system. Connecting the fresh air inlet 21 and the stack juncture |69 is a juncture 21a for admixing recirculated flue gases with fresh combustion air. Connecting the recuperator lower header |65 and the juncture 21a is a duct 28 through which fresh air and a controlled proportion of combustion products may be sent through the tube bundle of the recuperator.

Optionally, suitable means for introducing'air into the system is through inlet duct I5y forming a junction with duct 26 in advance of exhaust fan |43. Fresh air introduced at this point serves to cool the fan blades. The fresh air'and P. O. C. mixture handled by the fan is circulated back through the system through duct 23, and part is discarded to the stack 52 by regulation of valves and |46.

Optionally, suitable means are provided for removing additional waste heat from the stack gases and concurrently drying and preheating the solid feed material to the vessel 56. As shown in Figure 4, such means comprise an annular gas conducting jacket I5 surrounding the upper portion of the elongated vessel 56 projecting from the cap |46 and adapted to receive ue gases from the modified stack 52. Engaging the upper portion of the jacket ||5 is a suitable flue I6 adapted to remove the flue gases issuing from the annular jacket I5. Associated with the flue ||6 is an auxiliary combustion chamber ||1 adapted to provide additional heat to the combustion gases for drying the solid feed material as next to be described.

Surmounting the elongated vessel 56 (Figure 4) in this modified form of the apparatus is a drying chamber ||4 adapted to provide intimate contact between the solid feed material and flue gases. The flue H6 conducts gases from the jacket I5 and the auxiliary combustion chamber ||1 into the drying chamber ||4 at a controlled temperature indicated by temperature responsive element ||8. Horizontally disposed in the drying chamber ||4 are a plurality of inverted metallic deflecting angles |54 shown in detail in Figure 4a. The angles |54 are adapted to provide gas passages for the flue gases through finesize vsolid feed material, and the spent gases leave through duct |84.

Optionally, if the solid material being treated is of close-graded size through which gases will flow with only moderate pressure drop, by closing 'valve |83v and opening valve 18, the heating gases are deflected from the bottom of the metallic deilecting angles |54 (Figure 4) are forced to leave the system by passage through the broken solid 'pressuresaturated steam before entering the system.

In "thejjoperation of the heating system or heat.

.the combustion chamber manifold l. ally, fresh air may be introduced into the system .through port linduct 26 just in front of the y amounts.

lIl

vdevice associated with and forming a part of the Yreaction apparatus, fuel from gas header E (Figure 4) is burned at the burners 2Q, 21., and

.272 in controlled amounts. lThe highly heated They are then directed past the .into -the recuperator outer casing l5. In the recuperator casing -IS the products of combustion pass downwardly in indirect ycountercurrent heat exchange relationship with incoming tempered air and P. O. C., being directed through the recuperator in-an-elongated-path by the bales |42, and give 4up a substantial portion of their sensible Issuing from` the recuperator near the lower portion thereof, the partially cooled products of combustion pass by way of the flue 2t rthrough the fan 143 into, respectively, the stack 52 `and theY fresh air duct 2l in accordance with the arrangementof the gas-flow regulating valves |45 and 14S. Fresh air or other source of oxygen for combustion enters through the air duct 2l, is

mixed with a pre-determined quantity of combustion products at the juncture Ela, and the diluted or tempered air then passes through the -flue 23 back through the recuperator i5 and into Optionfan as previously described. From the manifold .l-'I the tempered Yand partially preheated air `passes downwardly through the metering valves i8 into the preheating ducts i9 and thence to the burners 2G, 2|, and 22, in suitably metered As shown, vthe preheating ducts i9 .are in indirect countercurrent heat exchange relationship with the combustion zone 24 and the contained upwardly-moving products of combustion. By this arrangement and correation of parts, a very desirable uniformly-controlled heating is secured for the elongated vessel 56 and theheating is carried outwth very high thermal Lefficiency.

In operating the preheating and heat interchange devices for drying, roasting., or Vfurther abstracting heat from the products of combustion issuing from the stack 52, or duct !92,.the prod- .ucts of combustion pass from the stack 52 into .the heat exchange jacket H5 and give la portion of their heat to the reactants in the preheating zone 80. Thereupon, the partially cooled products of combustion pass through theue Ils., are

optionally mixed with additional products of combustion generated in the auxiliary combustion chamber l il, and. thence are passed into the u preheater or dryer H4. Through the interstices formed in the solid material bed by the members 154, the combined' products of combustion gire up their heat to the soid materials and suitably ,preheat and dry the feed material .passing to the preheating zone S0 from the hopper 30.

Process for distillationin double aum/.Zus

In the operation of the apparatus provided with two superposed annular heat exchange devices in accordance with a preferred embodiment of the rst annular reaction Zone 33, andare raised in Ytemperature close to that of initial thermal decomposition. When treating non-Coking coals,

the-temperature of .initial deeomposition is-650l degrees F. ta 750 degrees F.' or (V340 degrees C. to

400 'degrees C.) Therefore in practical operation, the combustion and preheating systems are adjusted to produce a developed temperature of about 7G() degrees F. `as indicated by temperature .responsive eli-ment lil placed near the center :of

the vlower part of the reaction zone 33. The verf tical positioning of throat 34 is designed to meet these conditions, but'for all practical purposes, throat 34 is locatedv 4about two-thirds thcl height of the combustion chamber 24. Water vapor or initial products'of thermal decomposition forming in the reaction zone 33 pass concurrently with the solid material and pass into the heat exchange Zone El through the throat 34. The Asolid materials now preheated to about '700 degrees F. pass downwardly by gravity 'through the annular reaction zone dened'by the lower heat exchange device 3S and the elongated vessel 5E. As the'solid materials pass downwardly through this reaction zone 35, they increase in temperature as indicated by temperature responsive elements Sand l 4 located about in the center of the reaction zone outlined by annulus 33 and reaction vessel 56.

Low temperature distillation of the volatile vhydrocarbons from coal takes place between 750 degrees F. and 1200 degrees F. (400 degrees C. to 650 degrees C.), and, when the external combustion system is suitably regulated` to produce a temperature of about 1200 degrees F. (650 degrees C.) as indicated by temperature responsive element I4, the maximum yields of primary low temperature tars are obtained. On the other hand, if it is desired to obtain more fixed hydrocarbon` gases at the expense of lower tar oroil yields, the combustion chamber 24 is advanced in temperature to the desired point to yield the kind and qualityof products wanted. As the solid reactants pass downwardly through reaction zone 35, evolved gases and vapors or reactant gases or vapors pass countercurrently to the solids whereby heat is transferred to the upper solid materials.l Heat transfer by this kmechanism may be aided by introducing carrier gases, Yrecirculated distillation gases, steam, or other vaporous materials through the lower inlet pipe 31 suitably positioned in the heat transfer zone |35. These carrier gases pass upwardly through reaction zone 35, extracting heat from the downcoming solids and from the lower wall of reaction vessel5i `and transfer the heat to material higher up in zone 35. Thus the solid materials discharged from vessel 56 have been found that it is only necessary to heat oilbearing shales to about 700 degrees F. to 950 de- -grees F. (370 degrees C. te. 500 degrees C.) Ain order izo-extract the-optimum quantity of potential condensable oil. The combustion system temperature or the rate of movement of the shale through the system is adjusted to produce the above temperature conditions inside the reaction zone 35 as indicated by the temperature responsive: element i4? 4. @priorially, greater yieldsif fixed hydrocarbon gases can be obtained at the expense of lower oil yields by advancing the temperature of reaction zone 35 as indicated by temperature responsive element I4 or by the temperature responsive element I located in combustion chamber 24.

As an example of test results obtained in the operation of the double annulus system for distillation of oil-bearing shale, the following experimental data were obtained during test in a small pilot plant similar to Figure 4:

Shale charging rate, pounds per hou.r 347 Spent shale discharging rate, pounds per hour 266 Oil distilled from shale, pounds per hour 59.7 Air intro-duced as carrier gas at inlet 31,

cu. ft./hr 300 Distillatinu gas recirculated, through 31,

cu. ft./hr 723 Net yield of gas from Cystem, cu. ft/hr. 505 Heat renuired for distillation, B. t. u./pound of shale 685 Potential heat in gas made, B. t. u./pound of shale 780 Temperature, bottom of combustion chamber at point I F 1785 Temperature, middle of combustion chamber at point 2 F 1490 Temperature, top of combustion chamber at point 3 F 1180 Temperature of P. O. C. out recuperator,

point 5 F 595 Temperature vapors leaving retort, point I2 F 415 Temperature of shale in reaction zone,

point i4 F 855 Temperature of spent shale leaving reaction zone 35 F 640 Temperature of shale leaving preheater 30 F 130 Temp rature of vapors at throat 34 F 580 Potential heat discarded in spent shale,

` B. t. u.; lb. dry 1790 During the above test 26,377 pounds of shale were distilled and 4488 pounds of oil was recovered over a test period of about 76 hours.

Process for distillaton and gasification in multiple annali In the operation of the apparatus or system provided with a plurality of annular heat exchange devices in accordance with a preferred embodiment of the invention for distillation and complete gasification of so"id non-cokfng carbonaceous materials, reference is made to Figure 7. Solid materials, suitably dried or preheated as previously described in the discussion referring to Figure 4, pass downwardly7 into reaction zone 33 and into the intermediate reaction zone |55, where they undergo thermal decomposition and distillation in accordancel with the mechanism previously described for the double annulus heat exchange system. For example, products of initial decomposition pass concurrently with the solids in reaction zone 33, whereas the evolved tars, oils, vapors, and grease. issuing from the intermediate reaction zone |55 pass countercurrenti-y to descending solids and emerge through throat |58 to leave the system through duct 4I. This circuit is arbitrarily called the rich-gas circuitjand it confines oil vapors and relatively high heating value gases. Carrier gases generated in the lower reaction zone 35 enter the reaction distillation. zone |55 and move'counterourrent to descending solids and materially improve heat transfer to soids above. Solid materials, freey of volatile condensible hydrocarbons, but conf taining some gaseous volatile matter, enterthev lower reaction zone 35 where they undergo decomposition by reaction with steam or other reactant gases such as CO2 aided by heat extracted: from the lower part of reaction vessel 56 and by any heat impressed in the reacting vapors or gases by passage through a preheater 6| not shown in Figure 7 but described in relation to discussion of Figure 9. To solid reactants moving downwardly countercurrent to ascending gaseous reactants in reaction zone 35 reach thermo-chem'cal equilibrium, and gas formation is maintained at balanced reaction rates governed by the rate of heat transfer through the vessel 56 and the preheater 6| (Figure 9). The water gas reactions occurring in this section are endothermic, and their equilibrium can be adiusted by regulation of both steam concentration and temperature. It has been found that by regulating combustion chamber temperatures l'n'iicated by temperature responsive element within the range 1800 degrees F. and 2150 degrees F., and by adiustment of steam input to the system within the range 0.2 to 3.5 pounds per pound of solid material entering the reaction zone, that water gases havingr compositions expressed by Hz/CO ration ransing from 1.5 to 12.0 can be produced. Optionally, by introduction of regulated quantities of CO2 introduced and preheated with the steam p-roduct gases formed in reaction zone 35 can be controlled to have Hz/CO ratios n ranging down to less than 1.0. Gases formed in the above described process pass in countercurrent heat transfer relationship with the descending solids in reacton zone 35 and emerge through throat 34 into the intermediate heat exchange zone |59. This circuit constitutes the lean gas circuit, and products leave the system through vent pipe |51. Optionally part of the gases formed in reaction zone 3' are drawn through the intermediate reaction zone |55, where they serve as carrer gases in the rich gas circuit as previously described in connection with the double reaction zone system. Solid refuse or materials containing fixed carbon and ash move downward and out of the reaction zone 35 and are discharged from the reaction vessel 58 as il'ustrated in connection with Figure 9. rlhe revolving scraper d'scharge 53 moves the solid carbonaceous residue into duct 61, where it is picked up by discharge screw conveyor 50 in which cooling is accomplished by water or steam introduced through ports 15. The residue is transferred to reaction vessel 59, where further and complete gasification is attained by the well known producer gas reaction attained either in the static or uidized bed. Essentially carbomfree refuse is discarded from reaction vessel 59. The cooling agent introduced into discharge conveyor 50 serves to prevent admixture of gases or vvapors introduced into zone |35 with producer gases made in reaction vessel 59. Gases issuing from reaction vessel 59 pass through duct 1|, through dust catcher 12, andthence into gas receiving bustle pipe 5| from which they are distributed to the furnace heating the reaction vessel 56. Thus distilation vand complete gasification of solid -materials is attained, and -incoming natural' fuels' are converted or upgraded at high efficiency into the following. classified products:

(crleanfwater gasa'having a Iheating. value-less?: than325l'B- t.' uLlper cubic foot'suitablelfor produc-u tionzof synthetic liquid 1 fuelsv :or 'for Y"otherfi purposes."` yThe quality' of .the `lean f gas can'ibe; varied; and 'fcontroiled 'suchzthat its maj orf constituentsir Hzlsand .'ICO.' canbe'e varied...to'y suit conditionne". nti' use;;.y

Process for'.completegasification z'ndoublelv` annulusf..

In the operation of the apparatus orsystem" provided with two superposedannular heat exchange devices orrreaction zones inaccordance witha preferred embodiment ofthe `invention foircomplete gasication of non-Coking-l car; bonaceous materials reference is made to Figures' 1,"2f-and 4V3. Solid preheated reactive materials?. preferably size-graded and containingfa minie mum of line sizes, pass downwardly with gaseousY reactants such as steam or CO2 introduced'intol thesystem at'inlet 38 as previously described 'by the vessel 56 and the aligned heat exchangedevice 58. As the solid materials and lreactants` pass' downwardlythrough the annular zone33, reaction is initiated, and the evolved gases o1' vapors and reactants pass concurrently with the descending solids. The temperature of gases," vapors, and solids in the annular reaction zone 33"increases as the solids advance'down the an-4 nulus as -indicated by temperature' responsive elements 'l l, I andS, so placed that the'ther-'- mocouple-junctions are about midway'y between tlieinner topcylindrical annulus 5B andthe wall of'the'reaction vessel 56. The temperature in the annular reaction zone 33 iscontrolledI to lie within the range 1200 degrees Fpand 2000 degrees F. V(650 degrees C. and `1100 degrees C.) atthe point indicated by the temperature responsive element 9.' The mechanism of distillation, dee composition, and gasification occurring' in the annular reaction zone 33 has been observed to beas follows.' Primary or low temperature distillation occurs in the upper part ofthe vannuldsl in the temperature range 750 degrees Fr' to 1100 degrees F.V (400 degrees C. to 600 degrees C.)`, in` which water, CO2, condensable'oils'and high molecular-weight hydrocarbon gases* are the principal-"volatile products.AAV As the temperature advances between 1000 degrees F. to 1300 degrees (540degrees C. to 700 degrees C.) secondarydecomposition of hydrocarbons occurs to form" lighterweight hydrocarbon molecules, and `reactions between steam, CO2', hydrocarbons, and solid carbon are initiated, in which hydrogen is a'prin cipal product.s Residual volatile matter'in the fo'rm of "H2 also is eliminated from the vsolid f residue in the temperature rangelOOO degrees to '1300'Y degrees F." (540 degrees C. to 700 'degrees C'j As this complex mixture of reactants in creases in temperature from 1200 degreesF. to` 2000 degrees F. (650 degrees CftovllOO degrees'C.'), hydrocarbons are decomposed and reduced tor their'. elemental state, and' they 'r' contributeth'eirl'share by partial pressure to the equilibrium attained'by reactions proceeding steam, CO2, CO" andcarbon tomake up the wellknown water gas f equilibrium.' The f composition of 'thai-'product i gasesleavingthe annular reaction' zone 33 through throat 34 depends :upon theternperaturel and. theconcentration of principal reactants'. Reactive' solid materials and catalysts; such' as'. ii'onoxide promote. attainment' of"equilibri1im at'lower temperatures.Vv Ithasvbeen observedfth'ats byregulating thetfquantity of :gaseous reactantsf siamlorloiintroducedgat inle'ti38;.nltherangec lside the reaction zone.

from 0.2 to'"2.'0 .pounds :per pound offsolidsp' and' the' '1 temperature," as indicated vby'temperature.e responeiveelement 0,. to iangepetween' '1200. `de. grecs-*F1130 2000 degrees. F.' (650 degrees; 1C.` to lllfdegrees C.) product gases consisting ofafHzQ.. CO, CO2, CI-I4 and traces of N2 can be produced-f? such that. theirprincipal constituentsgI-Izand COfwilllbe'in'ratiofranging from 1.0 to 12.0.; thetemperature-of' the reaction Vessel 56 'isiinia- '2creased,' the Hg/CO ratio decreasesand'optionally, the Hz/CO ratio iincreasesas thez'concen-"l tration of steam .is..incr,eased. Thus, product gases having .H2/CO .ratio, ranging from 1.0 to=` 3.0Y suitable for production of synthetic liquidr uelsf. are ,produced-at thehigher temperature...

levels by the process. outlinedl'lerein.,v

In the double annular heat exchange system, solid carbonaceous materialsnot .enteringinto-y reaction in the reaction zone 33 descend `by zgr-avity intothe `lowerreactic'n zone 35,.where..

they Contact gaseous and.vapor reactants mov.j ingicountercurrently to the solids. The lower portion of 'theupper heat exchangel device Y58. (Figure 3) is made to extend sufficiently far down @the elongated vessel '56 so that, in` generaljth'e,...

gaseous or 4Vaporous products of reaction are re.-

moved 'from theannular reaction zone-33 near.. the zone .of optimum temperature. The gaseous' or vaporousreactants, suitably are oxygenated-.. gas fronrfthe group of steam; air, oxygen and" carbon dioxide', are introduced through inlet... S'iinto heat exchange zone |35 and thence into reaction. zone 35. Theymay. pass through'suit--` able preheaters 29 or 01"(Figure 9) located out'' Moving in countercur-v rent. heat. exchange relationship with descending" solids, the gaseous reactants in zone 35 Ycool the-. outgoing .solids and transfer heat back into ther reaction. zone where water' gas reactions pro'-,

ceed at rates and under the equilibriuml dictated*` bytemperatureof the reaction zone and concentration `of ,the principal reactants. It has.. beenfound that, by controlling the maximum temperature as indicated by temperatureY re'- sponsive rele-ment" I4' between the rangev 1200'de'- greesF; to 2000 degrees F. (650 degrees C. toill00 degrees C.) and the 'amount ofV steam` orotherf` oxygenated gas introduced through inlet 31 to range within 0.2 to 0:3 pound per pound of solids,

product gases consisting principally of H2, CO,

and-CO2 leavingthereaction zone 35 can benontrolled .such that the major constituents, H2-and.. CO, will. bein ratio ranging. from 1.0 to. 12.0.5. Solid carbonaceous -materials containing ,a rela?.v tively high percentage. of ash are discharged; from the reaction vessel Eas previously described ,2 in ,connection with. the discussion -relating to Figures '7 and 9.

Thus, in .this combined-process .of completer. f asicationY of solid non-caking, carbonacecus"v materials, natural` or pretreated soli-d materials.- areupgraded and-converted fto ,water.-.gasesf-.iofs controlled compositionine afhighly elicient mane ner. In order to .balancefthe system for com plete gasiiication of any non-coking coal; a pro-fcedure has ibeen v:developed Awhereby vthe Aweight relationship of reactantsA and heat, required fori'rv the reaction arel calculated from. the analysis-off: the coal to t the.-desir.ed endproducts.- Non-f-- cokingv coals :have oxygen contents, greater .fthanir 10.0 percenton the A-rnoisture tand Vashefreegbasi'sj., orf those 'having hydrogen/oxygenrratios less .than 1 0.60 on the :moisture and; ash-free basis tare .suitfe.. l abl'elforf.completer-gasiication inrthisfprocesszt In;

.the..scaleif.o,icoalziranmthese fincludeslignteeup;

essaies 17 to non-coking, non-agglomeratin'g bituminous coal. In further explanation of the manner of applying' the invention or system for gasification of coal to make synthesis gas the following example of a case for ash-free steam-dried lignite is cited as an equation:

In the foregoing example the figures represent pound mole per 100 pounds of ash-free steamdried lignite, except the B. t. u. figure, which represents the heat that must pass through the Walls of the reaction vessel 56 to carry out theV reaction when products leave' the system at 1000 degrees F.

As' a further example of the operation of theV process of complete gasification of subbitumi'nous coal in the double annulus system illustrated in Figure 3, the following operating data from a test in a pilot plant are cited:

Coal charged, pounds per hour 54.3 Moisture in coal as charged, percent 21.5 Ash in coal as charged, percent 5.8 Refuse out bottom of retort, pounds per hour 4.3 Ash content of refuse, percent 31.0 Tar or oil formed 0.0 Gas made, cubic feet per hour SGC 2,045 Analysis of gas made:

Carbon dioxide percent 17.9 Illuminants do 0.3 Carbon monoxide do 17.2 Hydrogen do f 61.4:Y Methane do 2.7 Nitrogen do 0.5 Heating value of gas, B. t. u. per cubic foot, observed 284 Specific gravity of gas .504 Steam used in Zone 33, pounds per hour 52.0 Steam used in zone 35, pounds per hour 50.0 Steam not decomposed, pounds per hour 57.6 Net heat used in combustion chamber 24,

B. t. u. per hour 325,000 Products of combustion recirculated cu.

ft. per hour 5,560 Temperature of bottom of combustion chamber at I F 2050 Temperature of middle of combustion chamber at 2 F 1900 Temperature of topof'combustion chamnberY at 3 F 1530 Temperature of leaving of combustion chamber at 4 F 1390 Temperature of P. O. C. leaving recuperator 5 F 7 55 Temperature of air and P. O. returned to recuperator l "F v 385 Temperature'of air and P. O. C. leavingrecuperator 8 F 1000 Temperature of products leavingl retort The above data represent average of 2li-hour operation during a test lasting about 100 hours.

Process for distillation of oz'Z shale This invention is also applicable to the distillation of oil-bearing shales comminuted to a suitable particle, for example as illustrated in Figure 4, the oil-bearing shales are passed through the annular reaction zone and are there suitably heated to a temperature between about 600 degrees F. to 950 degrees F. (325 degrees C. to 500 degrees C.) in which range substantially the whole of the oil content is liberated. Somewhat higher temperatures can be used, but under those conditions a much larger proportion of the hydrocarbon content of the shale is converted into xed hydrocarbon gases. A desirabie feature of this invention in connection with the distillation of oil-bearing shales is that a portion of the xed gases, ranging up to several times the xed gas formed, can be recirculated to provide a carrier gas. Optionally, steam can be admitted to the reaction annulus near its power portion to yield Water gas from the residual carbon in the shale. Alternatively, a suitable quantity of carbon dioxide or oxygen plus steam can be admitted to yield a higher carbon monoxide and hydrogen content in the xed gases resulting from shale distillation for use as synthesis gas.

Optionally by extending the length of reaction vessel 56 as indicated in Figure l0, a reaction zone H2 is provided wherein the above modification can be adapted.

A preferred process` for distillation and gasication of oil-bearing shales combines the process and equipment just described for distillation of carbonaceous materials in the double annulus system illustrated in Figure fl with the improved process hereinafter described for gasification of residual carbon in spent shale illustrated in Figure 10. Heretofore in less ercient processes for recovery of oil from oil-bearing shale, much potential heat isY lost byl discarding fuel values in the spent shale or by wasteful use of gases derived from the shale. By the process described herewith, in conjunction with the double' annulus process of distillation previously described, a large portion of high heat value fixed gases can be produced from average shale for purposes other than process requirements. Spent shale, from which oil vapors have been removed as previously described, and containing 2.0 to 26 percent by weight of fixed carbon plus volatile combustible constituents, can befurther processed to recover additional fuel values by the device indicated in Figure 10; The heated residue from reaction zone 35 feeds by gravity into reaction zone |12 denned by an extension of reaction vessel 56. Air', steam, oxygen or' carbon dioxide, or combinations of these gases, is introduced into inlet |99 and carried into the central portion of the reaction zone by duct |131 These gaseous reactants enter the reaction zone i12 through ports |74 and conical bailles H5, as indicated in Figure 10a. Combination of the oxygenated mixture with xed carbon or residual volatile matter oc curs, and the lean spent shale is gasiied by the wellknown producer-gas type reactions. Combustible gases are generated at high temperature,

and these ascend as carrier gases entering reaction zone 35, where they contribute both their sensible heat and potential heat to the process. By virtue of the central draft inlet, high temperatures are coniined` toY theinner portion of reaction zone llt, and' little heat is lost by radiation, although insulation layer l guards against further losses. Spent shale, now robbed of a substantial part of its potential heat, moves downward and is removed at the base of the reaction zone |72 by a suitable extraction device which may take the form of a sloping worm screw 5S equipped with quenching ports 'lo which substantially seals the system and prevents loss of fixed gases from the reaction zones. f

i9 Other processes employing the annular retort principle While the method and apparatus of this invention as previously particularly described relates to the gasification and distillation of subbituminous coal or lignite and the recovery of oil from oil-bearing shale, nevertheless, the same reaction conditions and equipment can be utilized in the destructive distillation of any noncaking carbonaceous material such as for example non-coking or non-caking subbituminous or bituminous coals. The method and apparatus of this invention as generally applicable to the gasication of lower rank fuels where the fuels employed as feed materials contain more than 10 percent by weight oxygen on a moisture and ashfree basis.

Process for making carburetted water gas continuously The process and apparatus of this invention can readily be adapted to the production of carburetted water gas continuously from non-caking lower rank coals as above dened by suitably modifying the central reaction annulus as shown in detail in Figure 8 of the drawings, wherein a suitable means for introducing gas oil near the zone of optimum reaction temperature is shown. As shown, an oil feed pipe 201 depends into or is positioned in the interior of the upper heat exchange Zone 46 and is provided with a nozzle Ml for spraying gas oil upon the incandescent bed oi heated carbonaceous material situated between the lower edge of the upper heat exchange device 58 and the upper dome |313 of the lower heating exchange device 36. Additionally, a proportion of gas oil is introduced in the upper portion of the annular reaction Zone 33 by means of suitable feed pipes |48. By this means, the gas oil feed to the initial lignite or other non-caking carbonaceous material being treated is first vaporized in the annular reaction zone 33 and is progressively heated to cracking temperatures as it approaches the Zone of optimum temperature and is thus cracked into a xed gas of high caloric content. This is supplemented by the gas produced when the oil spray from the nozzle il'i is likewise cracked on the incandescent fuel bed into a fixed gas.

It will be apparent from the foregoing description, there has been provided a method and means for carrying out reactions in a novel and desirable manner. A very excellent heat economyis secured by this invention. Heat transfer between an exterior source of heat, and a solid reactant is very greatly superior in my invention to any previously known device for accomplishing this purpose. Furthermore, the device is eminently suited to construction materials capable of withstanding the relatively high temperature often encountered in the endothermic reactions described, thus permitting a Very long equipment life. For example, the reaction vessel and the heat interchange elements may be made of corrosion-resistant chrome-nickel steels, alone or provided with a protective coating of chromium,

or the like.. construction in generally circular or cylindrical shapes, the usual expansion problems normally encountered are largely or completely obviated.

This application is a division of my application, Serial No. 589,450, led April 20, 1945.

Since many apparently widely differing embodiments of the invention will occur to one skilled in the art, various changes may be made in the method and means described and shown, without departing from the spirit and scope of this invention.

What is claimed. is:

The endothermic' chemical reaction process,

which comprises stage-heating a non-caking solid material having gas forming and liquii'lable constituents in size-graded condition along a vertically ranging course sealed from the atmosphere through which it passes by gravity, rst feeding the solids downwardly into an annular preheating zone of relatively large cross-sectional area in said course, directing heated gases upwardly in the central space bounded by the inner surface of said annular zone in heat-transfer and physically separated relation to said descending solids, next directing the descending solids into a second annular heating zone of lesser cross-sectional area than the rst named annular zone, subjecting the solids in said second zone to the heat-transfer action of products of combustion contacting the outer surface thereof, causing evolved gases to travel concurrently with the solids throughout substantially the vertical extent of said second zone, passing said evolved gases into the central space bounded by the inner surface cf said second annular zone to permit their ascent in heat-transfer relation to the descending material, passing said gases after their ascent to the central space bounded by the inner surface of the rst annular Zone to form the supply of heated gases named above, then di.

recting the descending solids into a third annular heat-transfer zone in which they are subjected to heat transfer influences applied both centrally and externally of said zone, causing relatively cool carrier gases to pass through the solids in said third zone in a direction countercurrent to the solids movement therein to extract heat units and evolved gases therefrom, and then passing the carrier gases from the top of the third annular zone to the central space bounded by the inner surface of the second annular Zone.

VVERNON F. PARRY.

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

UNITED STATES PATENTS Number Name Y, Date 956,371 Koppers Apr. 26, 1910 1,382,746 Schrader et al. June 28, 1921 1,618,566 Bergh Feb. 22, 1927 1,912,974 Debauche June 6, 1933 2,276,343 Reyerson et al. Mar. 17, 1942 As the apparatus is susceptible of.

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