Патент USA US2054154код для вставки
Sept. 15, 1936. H. J. CARSON 2,054,154 METHOD OF MANUFACTURING COMBUSTIBLE GAS Filed ' July 15, 1929 k0ot7uw%mv wkN 2,054,154 Patented Sept. 15, 1936 UNITED STATES PATENT- OFFICE 2,054,154 ' METHOD OF MANUFACTURING COMBUSTIBLE GAS Hiram J. Carson, Cedar Rapids,v Iowa. Application July 15, 1929, Serial No. 378,256 4 Claims. (C1. 48-202) This invention relates ‘to the production of admixed with the blasting air as‘ needed and de combustible gas and by-products such as oils, tar, and ammonia from bituminous fuel in gas‘pro ducers and the utilization of part or all of the 5 gases so produced in boilers and furnaces and the recovery of any remaining gases for other uses. The principal objects of the invention are to effect economies in such production and utiliza tion by certain improvements in the methods 10 employed. The invention comprehends improved methods ' for: the production and recovery of rich distilla tion gas and blue water gas, and also oils,'tar, and ammonia from bituminous fuel in conjunc 15 tion with the production of producer gas from the carbonized residue with‘ the distillation gases and products drawn off with a controllable amount of or no admixture therewith of the pro ducer gas; the utilization of part of the pro ducer gas by combustion in regenerators for highly superheating steam for the- formation of water gas, carbonizing the fuel and/or the pro duction of ammonia; the use of air and/or oxy gen in the carbonizing chamber for supplying a 25 part of the heat. required for carbonization and/or for the water gas reaction; the immediate utilization of part or all of the producer gas so formed by combustion in a boiler or furnace with the combustion products therefrom used for pre 30 heating the air for such combustion and/or the ' air for the producer; the use of combustion prod ucts from the boiler or furnace and/or steam as an endothermal agent for controlling the fuel bed temperatures in the producer and the forma 35 tion ‘of combustible gas; an improved heat cycle in producers and boilers in combination where by ,the gasi?cation and utilization of the heat of combustion of the fuel-are carried on in a highly efficient manner. >_ Zl‘he invention also contemplates the removal . of ash from the producer in liquid form to thereby eliminate the usual temperature limitationsv be cause of the fusing temperature of the ash, and ‘ permit operation at relatively high fuel bed tem 45 peratures and capacities and the use of cheap fuels with an avoidance of ash deposits in the boiler or furnace and the usual operating dif?cul ties and expense in connection therewith. To insure theeasy liquefying of the ash the 50 invention contemplates the use of preheated air sired. In the latter case the time interval re quired for ?uxing material charged with the fuel to work down to the slagging level is avoided. The invention further contemplates the intro duction of combustible gas with the blasting air in the bottom zone in case' of di?iculty in slag ging, which may for example be occasioned by a de?ciency of. combustible in‘ the fuel at the slagging level. . The blasting air may also be enriched with oxygen for further hastening combustion and liquefying the slag when desired. v'I'he invention also contemplates the use of part of the producer gas for the alternate heat 15 ing of two regenerative chambers and the heat stored therein in turn employed for highly super heating steam to be delivered to and utilized in the carbonizing chamber or zone of the producer. Other objects of the invention will more clearly 20 appear from the description and claims herein after following. ‘ _ In the drawing forming a part of the’applica tion, a suitable apparatus has been disclosed for the effective carrying out of the improved method 25 or process. In said drawing, Figure 1 is a part‘ vertical sectional view, part elevational view of‘ a gas producer plant and associated steam gen erating boiler for effecting the complete cycle of steps of the improved process. Figure 2 is a part 30 top plan view and part horizontal sectional view of the regenerators and generator shown in Fig ure 1, the sectional view of the generator cor responding approximately to the line A-A of Figure 1. Figure 3 is an enlarged vertical sec-v 35 tional view of the carbonizing chamber used in the gas producer and shown in Figure 1. And Figure 4 is an enlarged vertical sectional view, il lustrating more particularly the details of con struction of one of the air tuyeres, tuyere header 40 and supplementary inlet valve associated there with, shown is Figure 1. The apparatus may now be described in detail. In Figure 1, the gas producer I 2 is shown in section having mainly two zones. The lower zone I3 is the producer gas generating zone and con- / tains mainly incandescent fuel. The upper zone contains a carbonizing chamber I4 which is charged with fuel and ash fluxing material, as limestone, when desired, through any suitable in the lower zone of the fuel column. charging device as I5. The invention contemplates the use of a flux ing material which may be charged with the fuel Air blast inlet means are shown at level I6 through valved inlets I611. and Ilia’ and also at level I‘! through valved inlets Ho. and Na’. Means for admitting steam at level I‘! when de or introduced in the bottom zone of the fuel col umn in any suitable manner such as blown in. ‘ 2,054,154 , 2 sired for use in controlling fuel bed temperatures is indicated at l8. Air supplied through l'la' may be mixed with the steam and admitted to the fuel at level I‘! as shown. Stack gas is preferably used as an endothermal agent for controlling fuel bedtemperatures. This may be injected under pressure at level I'I_as through supply pipes 53 _ or inspirated by and mixed with air as indicated leading to the carbonizing chamber in the pro ducer.‘ . ‘ The valved steam inlet means are equipped with pressure’ regulators 4! and Ma to control the pressure of steam admitted to theregenera tive chambers. This control is effected by a pres‘ sure pipe 42 opening into gas passageway 20 of the producer. The gas burner 24- is . shown equipped with suitable air mixing means 24a for at inspirator l8. In heating operations with the gas containing I regulating the combustion air admitted through l0 10 a relatively high percentage of hydrogen a sub-7 stantial portion of the total heat of combustion is lost in the latent heat of the water vapor in the resulting stack gases. The hydrogen con 15 tent of the producer gas and the stack of water pipe 43; _ . I . Combustion is effected. in the boiler combus tion chamber or firebox 44 with the combustion products passing through the tubes and thence through opening 45 into an air preheater 46 15 vapor loss are substantially reduced if. an endo having a stack outlet 41. The combustion cham thermal agent such as stack gas containing little her may be substantially reduced in volume with ' ' or no hydrogen is used. The carbonizing chamber has an annular pas-4 20 sage around it of a relatively large area, at 20 to lower the velocity of the gases leaving the in candescent fuel and reduce or avoid the carry ing along of ?ne fuel particles in the gases. The annular passage is preferably narrowed at 2| to 25 increase the velocity of the gases and heat trans fer to the carbonizing chamber. The annular . passageway 21! and 2! is preferably enlarged at 22 to reduce the velocity of the gases at this point and to further a uniform passage of-the gases 30 around the carbonizing chamber. The producer gases pass from 22 through a conduit 23 and a burner and air mixer 24 into the boiler 25. The wall of the carbonizing chamber II is preferably made of heat resisting metal to per 35 mit a relatively high rate of heat transfer theree through, but may be made of any suitable mate rial. This chamber may be in the form of a trun cated cone with the larger end down to facili ' tate the downward passage of the fuel and avoid heat radiating surface provided as indicated by the line “a with resultant economies. The com bustion and producer. air may be supplied by a 20 fan or blower 48 with preheated air .offtakelt from the air preheater leading to the boiler bum er 24 through pipe 43 and to the producer and regenerative chambers as before described. stack gas passageways 50 and 5] are shown leading to a blower 52 for withdrawing the stacl-r~ gases either from the inlet or outlet of the air preheaters and delivering these gases through pipe 53 to level ll in the producer. When the air inspirating effect of the air admitted through 30 Ila to inspirator i8 is relied on for drawing the stack gas into the producer, the blower 52 may be dispensed with. d _ ' The producer‘is shown with a hearth 54 ‘pref erably sloping toward a slag discharge opening 55 which is normally closed by any suitable means such as ?reclay. A second slag discharge open .ing 55a is shown at a higher level for use when iron or metallic ore is charged with the fuel as sticking or hanging. The carbonizing chamber a i'iuxing agent.- The metal may be drawn off 40 preferably contains an assembly'26 in the center at the lower level 55 with the slag drawn off at ' v I , thereof. This assembly is shown enlarged in the higher level 55a. ' The pipe 56 opening into air inlet at level l6 Figure 3, and is more fully described hereafter. An inlet 2'? for steam is shown near the bot ' indicates admission means for gas or oxygen for tom of the carbonizing chamber, supplied by a mixing with the air to effect combustion ‘or vertically disposed conduit 28 passing through the raise the temperatures in thefuel bed at this assembly aforesaid and fed and supported by a level as desired forlsla-gging‘ the ash. This con nection 56 also indicates means ‘for supplying ' pipe 29.. Pipe 2911 connected into pipe 29 indi ' > cates a means for admitting oxygen and/or air ?uxing material into the air blast. Another opening into the fuel bed’ at any suit 50 to the lower portion of the carbonizing chamber able level as 51 is shown for the introduction of 50 to supply any heat required for the water gas ?uxing material as desired. reaction and/or carbonization of the fuel. The producer is equipped with a valved gas An assembly cap or valve 30, adjustable as by a cable 3| for regulating the division of flow of outlet 58 in the top of the carbonizing chamber . 55 gases through the assembly 26 andthe fuel is shown. / Two regenerative chambers 32 and 32a as indi cated in' Fig. 1 and shown in Fig. 2 are connected to the passageway 22 of the producer through passageway 33 andvalved inlets 34 and 3411. These regenerative chambers are connected to a stack 36 and an air preheater 36a through valved outlets 35 and 3511. This preheater preheats the combustion air to the regenerators and has air 85 inlet and outlet as indicated at 36a’ and 36a". Each regenerator is adapted for the combustion to for the withdrawal of distillation gas and vapor 55 and any other gases mixed therewith to such farther point as is desired. . In the partial plan view of Fig. 2, a generator ' section on theline A--A at level I6 in Fig. 1 is shown. Air inlet headers are indicated at l6 and 60 I6’, and tuyere openings in the long sides of the 1 generator section are indicated at l6". ‘Doors are indicated at El opening into the generator through‘ removable blocking as 62. The jets of air and stack gas and/or steam from the tuyéres 65 in the long sides of the generator practically cover the hearth thus insuring an active use ‘of of producer gas therein entering through pas sageway 33, valves 34 and Me with combustion air admitted through air inlets 31 and 31a into the respective combustion chambers, only one of‘ In Fig. 3, an assembly 26 is shown in a frag mental-3r section of the carbonizing chamber I4 70 with steam and/or oxygen and/or air admission which is shown and referenced 38. means 21 supplied by pipes 28, 29 passing through Each re generator is equipped ‘with valved steam inlet ' means 39 and 39a and valved steam outlet means 75 40 and Illa connected into steam supply pipe 29» the entire hearth area. the assembly as described for Fig. 1. ' ‘ . ~ This assembly is preferablymade of a series of ‘open cylinders or cones 66 of any desired form 75 3 2,054,154 and preferably in the form of truncated cones with the bottom of each cylinder or cone pro jecting over and below the top of the next lower one thus forming a protective skirt around the upper end of the next lower cylinder or cone to 4lJ-a into the bottom of the carbonizing cham ber through inlet 21. The highly superheated steam so admitted in contact with the hot carbon in the base of the carbonizing chamber forms some water gas and this with any undecomposed ‘ steam more or less blankets the bottom of the prevent fuel falling therein and to provide annu lar openings 61 for the escape of volatile matter carbonizing chamber against the admission of ' , from the fuel into the open passage through the‘ the low grade producer gas. ' . series of cylinders as indicated by arrows. Fig. 4 shows a fragmentary section of a gen erator wall with an air blast tuyére therein. The tuyeres at each level are supplied by tuyere head er pipes ‘I I, which are supplied by air distributing pipe through valves 12. The tuyére nose ‘I3 is 15 shown projecting beyond the generator wall and 10 The water gas and steam and/or producer gas I sweeping upwardly through the fuel drivesvoff l0 any remaining volatile matter in it and enters the assembly through the bottom of annular openings as at 61, or passing up through the fuel passes out through upper o?take 58. 'The cap 30 on the assembly may be-raised or lowered 15 cooled by water~entering through pipe 14 and for adjusting the ?ow ‘through the fuel and the discharging through pipe 'I4—a. assembly as desired. The pipe 56, shown inserted in a tuyere, indi cates means for the introduction of combustible gas or oxygen for mixing with the air and fur thering combustion at this level. ' Fluxing material in powered form may also be so admitted into'the blasting air through pipe 56. The improved process is carried out in the 25 apparatus described, as follows: A ?re is kindled on the producer hearth 54 and the producer ?lled with fuel (preferably coke at the start) which is replenished with prefer ably bituminous fuel thereafter through charg 30 ing opening ‘15. Valve 23, when provided, 7 is _ The valve 58 is adjustable and with the rate of steam admission in the bottom of the carbon izing chamber also adjustable the admixture of 20 any desired portion of producer gas'with the dis tillation gases which are drawn o? at 58 may be effected. The blue gas and steam and any producer gas mixed therewith in passing through the cylin-. 25 ders of the assembly produce a vacuum effect which draws the gas. from the fuel being carbon ized in through the annular spaces 61 into the stream of gas. The gas and vapors are accord ingly withdrawn from the fuel substantially as 30 16. At the start the lower slag opening ‘55 may evolved and, mixed with the blue gas and steam, leave the assembly through 38 and pass out be left open so some burned gases may be dis through 58. open. Air is admitted through tuyeres at level charged here with a resultant drawing down of 35 the heat to highly heat the hearth. ‘As air is admitted and the fuel bed becomes hot the oxy gen of the air is burned to CO2 at ?rst and then ‘ decomposed into carbon monoxide mostly. This gas passes up‘ through the fuel bed, preheating 40 the fuel, leaving ‘it at passage 20, and passing ' The heat for carbonizing the fuel is supplied by the sensible heat of the blue gas and any assembly and is supplemented by: - (a)—The heat in the producer gas passing around the carbonizing chamber. (b)--The use of additional amounts of excess 40 around the carbonizing chamber, passes out to steam preferably superheated to the highest prac the boiler through passageway 23 and burner 24. ticable extent as above described. by the com bustion of a portion of the producer gas in re Air for effecting combustion of this gas is admitted through 43. The gasis burned in com .bustion chamber 44, and passing through the boiler enters the preheater 46 throughpopening 45. This preheater may be of the recuperative type but is preferably of the regenerative type and adapted for operation at high stack temper ' 50 atures, say 800 deg. and more. The burned gases in passing through the pre heater 46 preheat the air admitted to the pre 35' undecomposed-steam passing through it and the generative chamber. ‘ (c)—Passing part of the producer gases 45 through the carbonizing chamber and using the sensible heat thereof, and/or 7 (d)—Admitting air and/or oxygen‘mixed with or independent of the. steam in the lower portion of the carbonizing chamber as through 21, or 50 equivalent means for effecting combustion and ‘the liberation of additional heat in the bottom _ heater as through fan 48, the preheated air being zone of the carbonizing'chamber. The carbonization temperature may accord taken off at 49 and'supplied to the boiler burner 55 55 through 43 and to the producer at levels l6 and ingly be varied and controlled by the above , I‘! as desired. As blasting with the air continues methods of heating. The hydro-‘carbon vapors are drawn off sub at level IS, the heat liberated by the burning of stantially as formed through assembly 26 and the carbon to carbon monoxide continually in outlet 58 with a recovery of ‘the condensible creases the fuel bed temperature. When the de sired fuel bed temperature is reached stack gas hydro-carbons in liquid form with little or no 60 drawn off hot at 45 ahead of the air preheater di?iculty from the fuel arching or sticking dur ' or at 5| in the outlet of the preheater may be forced under pressure by fan 52 or inspirated by air injected through pipe l'|—a. and I8 through 65 tuyeres at level II to absorb the excess heat by the decomposition of the CO2 in the stack gases and keep the fuel bed temperature at the desired point. A part of the producer gas is burned alter 70 nately in regenerators 32 and 32-41., with ‘air from preheater 48, or 36-0. admitted through valved inlets 31 and 3'|-a. While one regener-' ' ator is being heated, steam is admitted to the other through valved inlet 39 and 39-a, and is 75 passed ‘superheated through valved outlets 40 and ing carbonizing. , a I. a ' The volatile matter of bituminous‘ fuels is of varying composition and distillable at different temperatures. The volume and quality of the 65 volatile matter given off varies with the tem perature and time of heating. When the volatile matter distilled oil‘ at relatively higher tempera tures passes through cooler fuel some or all of it is condensed on the, cooler fuel. This con 70 densate incases the lumps or particles of fuel in a liquid envelope often of a plastic nature which is not again vaporized until the fuel passes into a zone of higher temperature. Meanwhile the lumps and particles contain volatile matter dis 75 ’ 2,054,154 tillable at relatively lower temperatures which, ,' being partially :or ‘wholly con?ned within the liquid envelope, causes the fuel to swell. With the volatile matter evolved from bituminous fuel more nearly is an approach made to a closed heat cycle with a reduction in the volume of ' escaping stack gases. The use of the boiler stack gases for preheat ing all air used in'the combined process and the as it is heated removed from contact therewith under temperatures and partial pressure condi return of a portion of the stack gases to the pro tions above the condensation point, the time re-= , ducer insures a relatively higher mass of the air quired for distilling off the volatile matter at any to be preheated than in the outgoing stack gases, given temperature is greatly reduced; cracking with a more nearly complete'recovery of heat in of the hydrocarbons so evolved is avoidedgand the condensible portion of these hydro-carbons may With the hydro-carbons drawn off as formed and cracking avoided, the heat required for car-= 15 bonization is substantially less.‘ The invention contemplates the distillation of the fuel under controllable temperature condi tions to permit the evolving and recovery of con densible hydro-carbons of varying qualities as desired. ’ . _ The passage of the producer gases around the carbonizing chamber insures the relativelyrapid heating and carbonization of the fuel in contact with the chamber wall. The admission of highly 25 superheated steam and/or air and/or oxygen in the lower zone of the carbonization chamber and its passage through the fuel and the assembly in sures the drawing ‘off of the volatile matter under temperature and partial pressure conditions 30 which avoid condensation and permit the re covery of the oils'and rich gases. the waste gases than is obtainable with usual 16 methods. ' . The use of a portion of the producer gas for be recovered in liquid form. . 20 d’ The use of combustion in regenerators for superheating steam further increases the mass of the air to bepreheated in proportion to the stack gases 15 ~from the boiler or furnace. ' - The air preheater SG-m recovers any otherwise waste heat from'the regenerators and preheats the combustion air for the regenerators. " When this preheater is used the. valve 49a in Fig. 1 is closed. When air‘ from preheater 46 is used in the regenerators valve 36a" is closed. ,The invention provides for the‘ production, utilization and recovery of combustible gases and by-products of various qualities from a variety 25 of carbonaceous fuels. ' The steam superheating regenerators may be dispensed with whenever it is desired to im mediately burn all of the gases produced, in. which case the upper zone of the producer forms the carbonizing chamber with chamber It su?icient undecomppsed steam, assistsin the de " omitted and the fuel ?lling the entire upper space. volatilization of the fuel and results in the forma Combustible gases of different qualities may tion of ammonia, which mixed with the rela‘ 35 tively small volume of rich gases is easily recover be produced and recovered, and the steam super heating regenerators dispensed with when the able. ' 5 The steam or stack gas enters the fuel ‘at level needed heat for carbonizing the fuel is supplied II, a- sufficient distance above level-J6 so as to bypass the lower intensely hot zone without an by passing the required amount of producer gas and/or air and/or oxygen’through the carboniz appreciable cooling action on any liquid slag in ing that zone. , ' With the producer, boiler, and regenerators at the desired temperature throughout for regular operation, highly superheated steam‘ and/or air 45 or oxygen is admitted in the bottom zone of the carbonizing chamber and the resultant gases, oil vapors, and ammonia are continually drawn off at 58, the carbonized fuel descends into the pro ducer gas generating zone i3, where it is con» 50 tinually blasted by highly preheated air from air chamber. 1 ' The economics and advantages of the di?erent 40 features of my invention are obvious: - Provision is made for the recovery of rich gas, oils, tars, and ammonia from bituminous fuel which- is now lost orburned in boiler and other furnaces. The use of controllable amounts of highly superheated steam and/0r air or oxygen and the withdrawal of vapors without condensation in sures the rapid carbonization of the fuel. preheater 46, with the temperature controlled The more valuable constituents of coal are re ' by steam or stackgas separately or mixed with covered for higher uses with the low grade car air admitted at the higher level for controlling fuel bed temperatures. Any ?uxing material, as limestone, charged 55 with the fuel for lowering the melting point of the ash has the additional advantage of further ing. the production of ammonia. It also carries down a substantial part of the vsulphur in the 60 fuel ,into 'the slag. With the stack gases leaving the boiler at rela - tively high temperatures and used for preheating air, the boiler heating surface 44a provided oper ates at a higher temperature differential with 65 an increase in heat'transfer per unit of heating surface. With stack gases preferably hot used as an endothermal agent in the producer, prac tically all the sensible heat in this portion of the stack gases is returned to the process. The high 70 er the preheat in the air to the producer, the greater is the cooling action required for keeping the fuel bed temperature down to any desired point. The hotter the'stack gases used as an endothermal agent, the more of these gases may 75 be used for a given amount of cooling and the 45 50 bonized residue gasi?ed and immediately used in boilers'or furnaces. The present limitation in producer gas produc tion occasioned by a fusing temperatureof the fuel ash is de?nitely removed by removing the ash in liquid form. ' Cheap, abundant fuels are made available for gas production. ' , Theme of the fluxing material as limestone for 60 liquefying the ash has the additional aiilrantage of furthering the production of ammonia and methane, and carrying sulphur into the slag. ‘The usual dimculties due to the sticking and‘ 65 hanging of fuel are overcome and "the rich gases and hydrocarbons recoverable in liquid form are recovered under controllable tempera ture conditions with a controllable admixture therewith of other gases. The production of ammonia is favoredby the 70 introduction of steam in the carboniz'ing chamber vwith the temperature therein controllable within the optimum limits for ammonia formation. The different features are all combined to- pro- u 5 2,054,154 vide methods for the production and recovery oi.’ rich gas and byproducts from the coal at rela tivelyvhigh rates in apparatus of a given size with the e?icient production and utilization of > producer gas in a partially closed heat cycle. The use of stack gases as an endothermal agent limits the formation of hydrogen and lowers the stack losses by reason of the decreased water vapor content in these stack gases. 10 1 - With the gas used hot as it leaves the producer and mixed with air heated to a relatively high temperature combustion is greatly accelerated and the combustion space required for a given capacity is substantially reduced with a resultant reduction in radiation, losses.‘ The heat radiat ing power, of the carbon monoxide ?ame is rela tively high and with the provision of heat radiat ing surfaces in the combustion chamber, ex tremely high rates of heat transmisson to the boiler or furnace material are obtained. The reduction of the fuel to ash in the pro ducer results in a relatively‘ ash free gas being delivered to the boiler or furnace with a result that the heating surfaces remain clean for an 2. The herein described improved method of manufacturing producer gas vfrom carbonaceous fuel in a gas producer having .an upper carbon izing zone and‘ a lower producer gas zone, which includes: continuously air blasting the lower portion of the column of fuel in the producer gas zone and maintaining the slag liquid at the base of the column; drawing off the producer gas thereby formed from the upper portion of said lower zone; burning a portion of the pro 10 ducer gas in regenerators; highly superheating steam in said regenerators; passing said highly super-heated ‘steam and an oxygen-containing ?uid to the lower portion of. the carbonizing zone; and passing such steam and ?uid upward 15 ly through the carbonizing zone and drawing off the generated and distilled gases liberated there by and admixed therewith. ' 3. The herein described improvement in the method of manufacturing combustible gases 20 from carbonaceous fuels in gas producers hav ing an upper carbonizing zone and a lower pro maintenance expense, etc. in present boiler prac tice necessitated by ash deposits on the, heating ducer gas zone which includes: continuously air blasting the column of fuel in the lower portion of the producer gas zone and maintaining the 25 slag liquid; drawing off the producer gas there by formed'from the upper portion‘ of said lower surface and the annoyance and expense caused zone substantially without contact with the fuel by the discharge of ?ne ash with the stack 30 gases is avoided. From the preceding description, it is evident that the improved method makes possible: the recovery of the valuable gases ‘and by-products in the carbonizing zone; admitting superheated steam substantially centrally and at the bottom 25 inde?nite period, vand the frequent shutdowns, of coal now used in boilers and furnaces on a 35 large scale for higher uses with the immediate consumption of the relatively low grade carbon residue and the highly e?icientand practically continuous operation of high capacity boilers and furnaces. pendent of the producer gas generating process proper, that is, useful results extraneous of the _ ‘zone and simultaneously drawing into such ad mixed steam and gases, the vapors and gases when and as distilled and released from the fuel in said upper portion of the carbonizing zone. . While I have herein referred speci?cally to steam generating boilers and. furnaces, it will be understood that the invention is equally ap plicable to other heat utilizing devices, by which term “heat utilizing devices” as used in the de 45 scription and claims, I mean devices for ac complishing useful or productive results inde gas making cycle proper. of the fuel in the lower portion of the carbon izing zone; and conducting the steam admixed with the formed and liberated gases from the fuel through an apertured passage within the fuel in the upper portion of said carbonizing - Having described my invention, I claim: 1. In the manufacture of combustible gas from bituminous fuel in apparatus including a gas producer having an upper carbonizingzone and a lower producer gas zone and two regen 55 erators, the improvement which consists inair blasting the column of fuel in the lower portion of the producer gas zone, drawing off the pro--_ ducer gas formed thereby from the upper por tion of the lower zone substantially without con 60 tact with the fuel in the carbonizing zone, burning a portion of the producer gas alter nately in each of the regenerators, admitting -steam alternately to each of the regenerators, passing the steam highly superheated therein 65 from the regenerators to the lower portion of the carbonizing zone and thereby substantially blocking o?’ admission of producer gas to the carbonizing zone, passing the steam through the carbonizing zone, drawing off the distillation 70 gases liberated thereby and admixed therewith from the top of the upper zone, and drawing o? ash and clinker forming material as liquid slag. 4. In the manufacture of combustible gas 40 from carbonaceous fuel in a generator wherein the fuel descends ?rst through a distillation zone and thence into an incandescent, up air blasted zone with resultant generation of pro ducer gas therefrom, the improvement which 45 consists in: con?ning the fuel in its passage through the distillation zone to a continuous sol id column of substantially annular form and ad vancing the fuel downward through said annu lar column formation solely by gravity; con 50 tinuously heating said annular colum'n‘ portion of the fuel throughout its entire height by pass ing the generated producer gas vertically up ward along the outer‘ side of the annular col umn portion of fuel but without contact of said 55 producer gas with the fuel in the annular col umn portion; and, simultaneously with said heating by the producer gas, introducing highly heated ?uid into the fuel at the lower portion of said distillation zone, passing said ?uid upward ly through said annular column portion of the fuel to effect distillation thereof throughout its height, and withdrawing laterally inwardly and upwardly into the interior of the annular column portion of the fuel the ?uid and distillation prod 65 ucts simultaneously evolved by and from the ?uid and heat of said producer gas, progressively at frequently vertically spaced intervalsfrom the inner side of the annular column portion sub stantially throughout the entire height thereof. 70 HIRAM J. CARSON.