US3004839A

US3004839A - Gasification of carbonaceous solid fuels

Info

Publication number: US3004839A
Application number: US541582A
Authority: US
Inventors: Earl L Tornquist
Original assignee: Northern Illinois Gas Co
Current assignee: Northern Illinois Gas Co
Priority date: 1955-10-20
Filing date: 1955-10-20
Publication date: 1961-10-17
Anticipated expiration: 1978-10-17

Description

Oct. 17, 1961 E. ToRNQUls-r 3,004,839

GASIFICATION OF CARBONACEOUS SOLID FUELS INVENTOR.

Oct. 17, 1961 5.1L. ToRNQUls-r 3,004,839

GASIFICATION 0F CARBONACEOUS SOLID FUELS Filed Oct. 20, 1955 3 Sheets-Sheet 2 n l r IN V EN T QR. zzz/Z l. @mg/@wi Oct. 17, 1961 GASIFICATION OF CARBONCEOUS SOLID FUELS Filed Oct. 20, 1955 E. L. TORNQUIST 3 Sheets-Sheet 3 United States Patent O .3,604,832 .y ,Y GASIFICTIQN ACRRONACEOUS SOLID FUELS y y Earl L. Tornqnist, Ehnhrst; lll., assig'nor to Northern' Illinois Gas Company, Aurora,y lll., a corporation of Illinois Filed Ot;l 20,- I955, Ser". N.- 541,582 19 Claims. (Cl. 48-197) 'Iliisinv'entionrelates to means and method or process by which a gas having a high heating value per cubic foot may be produced in an eicient and economical manner from' ca'rhona'ceduslv solid fuels such as coal, char, lignitev and the lilie. Such a'Y gas is 'intended as a substitute for natural gas and shouldpro'vide in the neighborhood ofY 1000 Btu; perrcubicfot. A Ymixture of cornbustible gases in whichl 90% or more thereof comprises methane he very satisfactory for this purpose. A

One of the more generally accepted methods of ob-I taining methane from coal has embodied the steps pf rst generating ai synthesis' gas of carbon monoxide (160)' and hydrogen gas (H2) and then passing the synthesis gas over a nickell catalyst at about 600 F. and 300 p.s.i.aftov produce' the methane'. However, care must be taken to be Vsure that' the' synthesis gas does' not con- -tain sulphur. Even traces thereof 'wil1'cause"poi soning of the'catalyst andpurication is, therefore, a vital step in the process.

The synthesis gas was usually generated at temperatures inthe range of 1600 F. to 3000" and the reaction" is endotl'1e-rrnic heat is usually supplied by burning coal with relatively pure oxygen, hereinafter referredito as tonnage oxygen, since if air were used directiy the high nitrogen content of the synthesis gas would make it unsuitable for conversion to methane. Although the` methanization step wasI highly exothermic, the heat of the reaction was liberated at around 600 F. so that itV was too low to be used forpthe production ofhydrogen' and therefore a considerable amount ofv tonnage oxygen and coalconsumedin supplying thisheat was not'V ethciently used. At the same time,v because the methanization step was highlry exothermic,u aswitness the followingequations typicalI of the reaction,r m'e'ans had to be provided to dissipate the reaction heat.

In each reaction,- itwill be noted that four moles of syn-` thesis gas are required to produce one mole of methane, and if the four moles are all hydrogen, one mole of CO2 in addition is required.

The heat of reaction-required fory producing a mole of carbon monoxide is about twice that requiredrfor producing a mole of' hydrogen. Sincey many of the' re actions for forming methane require ratios ofca'rbon monoxideA to hydrogen different than-in the synthesis gas' resulting from-the gasiiic'tion` reactions, a supplementary reaction such as' the wat'erg'a's' shift method' needs tobe employed to' obtain the proper ratio of carbon monoxide' to hydrogen gas. Itiv'vill'thus he readily apparent'fromI all these factors thatt -it` becomesexpensive to produce` a' pipeline gas consisting principally of methane by? method. Moreover', the; process is lovv in) overall eniciency while the'tonnage oxygen'requirenients" are high;

Therefore a first' and oliject'of the invention to providel a means" andlor'me'thod for producing a gas' such as' described consisting' pihily `of' methane' in*1 which proportionately less' amounts of synthesis gas;

3,004,839 Patented 9ct. 17, 1961v ICC either carbon monoxide or hydrogen gas will be required per mole of methane produced.

A further important object of the invention is to provide aA method of producing a gas sufficiently rich in methane as to he of pipeline quality in which method the production of hydrogen and methane formation reaction steps may he caused to take place `at temperatures so related to eachY other as to permit the exothermic heat of one reaction to supply a substantial portion of the endothermic heat required for the other reaction.

A further important object of the invention is to provide a method of producing a gas sufficiently rich in methane as` to be of pipeline gas quality which method willv not be appreciably aiected by the presence of sulphu'r.-

A further andV important object of the invention is to provide a method of producing such a methane rich gas of pipeline gas quality in which method the unreacted synthesis'y gas of the product from the methane forming step Which is of low heating value may be advantageously returned to the system so as not to lower the quality of the gas supplied to the pipeline or reduce the efhc'iency of the system. n l Y further important object of the invention is to pro-l vide anethod' of producing suchY a methane rich gas of pipeline' quality without necessity of having to go to complete conversion of the synthesis gas into methane.

.A further 'important' object of the invention is to provide' a: system' or method of producing such a methane rich gas of pipeline gas quality inf which system or method the' exot'h'ermic heat given ofi by one reaction and the endotheiinic heat required forv the other reaction may be sobalanced as to' require only a relatively small amount of tonnage oxygen in the' system.

In' accomplishing' the above objects, it is proposed to produce' methane by the reaction of hydrogen gas with carhonaceo'us' solid fuel such as' coal according to the following formula:

However, in the hydrogenation of coal,- the' methane content of the product gas cannot exceed the equilibrium conditions between hydrogen and methane', assuming an excess` of carbon is present. For instance, the equi`I libriurnv conditions between hydrogen and methane in a system proposedV herein, would result in al concentration of 10% 53H4 and 90% H2 at 1520 F. a` reactor pressure of about 3.2 atmospheres. At 20 atmospheres, the concentration would be approximately V33% methane and 67% hydrogen, yand at 541 at rnosp'h'er'es,` the ratioVK would be 50% methane and 50% hydrogen. At '100"atmospheres`, the concentration would' approximately 62% methane and 38% hydrogen. 'I'liuspjit is apparent that to obtainl a product gas of essentially pure' methane; would require extremely highl pressures which generally would not be desirable in actual'4 practice. Further, to obtain methane concentra'- tions equivalent tothe equilibrium conditions, requires a long-time Contact between the hydrogen and theV coal. `It is thereforev an important object of this invention to provide aV method of hydrogenation of coal that will permity operation at generally accepted operating press'ures4 in thegeneral range of 40 atmospheres and at temperat'ures high enough that the exothermic heat of this reaction can be made useful for the 4production' of hydrogen used in the process and effectively reuse the un- Ieacted hydrogen in the system.

A further object of the invention isV to provide a method or' sys'teri of producing methane gas in which carbonV may be lfydrogenated to methane utilizing hydrogen in excess oftht' to maintain equilibrium between methane, carbon, and hydrogen in the product gas, the excess hydrogen being kept in the system and the hydrogen consumed being formed by a reaction between steam and more carbon. According to the herein described process,-these reactions may be caused to take place in the same or separate vessels but in either arrangement, the two reactions are so thermally related that all but a relatively small proportion of the endothermic heat required for one reaction is supplied by the exothermic' heatof the other reaction.

YA further object of the invention is to provide means and method of producing methane in which carbonaceous Vsolid Vfuel is circulated between two zones, in one of which zones hydrogen is introduced in excess of that required to maintain equilibrium between the methane formed Yand the hydrogen at the operating temperature and pressure and in the other of which zones water in the form of steam is introduced to react with the carbonaceous solid fuel to produce hydrogen in sucient quantity to replace that being consumed in the rst zone, themethane and excess hydrogen being removed from the rst zone, the methane separated from the excess hydrogen, and the excess hydrogen returned to the first zone, the hydrogen produced in the second zone being added to the iirst zone to maintain the required ratio of hydrogen to carbon in said zone.

A further object of the invention is to provide a system embodying means and method of producing methane in which carbonaceousV solid fuel is alternately reacted with steam to form hydrogen and then with hydrogen to form methane, hydrogen being present in proportions in excess of that required for equilibrium conditions between the methane formed and the hydrogen at the operating conditions, and substantially only'methane being removed whereby the reaction of carbonaceous solid fuel with steam need only be sufiicient to replace the hydrogen being consumed in the forming of methane.

A further object of the invention is to provide a method or system of producing methane gas in which carbon may be hydrogenated to methane utilizing hydrogen in excess of that to maintain equilibrium between the methane and hydrogen in the product gas, approximately half of the methane produced being converted to hydrogen to supply the system with the amount of hydrogen consumed in the process to produce methane and the balance being separated from the hydrogen and made available for distribution use.

A further object of the invention is to provide a method of producing methane in which carbonaceous solid fuel such as coal may be fed to one vessel and water in the form of steam Vto a second vessel, the coal being reacted with hydrogen in the first Vessel to produce methane and a portion of the methane being diverted to the second vessel to react with the steam to supply the hydrogen consumed in the hydrogenation step, the amount of hydrogen present in the first vessel exceeding that consumed in the hydrogenation ystep by an'amount sufficient to maintain a desired approach to equilibrium in the systernV between methane rand hydrogen at the operating temperatureV and pressures, and the excess hydrogen in the outlet gas being continuously returned with the newly manufactured hydrogen to the first vessel to maintain thesystem under the operating conditions required.

Many other objects and advantages of the invention will appear from the description of the invention which follows particularly when taken with the accompanying drawings in which:

FIGURE 1 represents in diagrammatic form the steps in a preferred process for producing methane gas of pipeline quality; while FIGURES 2, 3 and 4 illustrate in diagrammatic form alternative systems for producing such a gas; Y

FIGURE 5 illustrates in diagrammatic form an alternative arrangement wherein the system is adapted for utilizing caking coals as the source of carbon; and

FIGURES 6, 7 and 8 illustrates in diagrammatic form further embodiments of a system according to the pres- Y 4 Y ent invention in which the hydrogen beingY consumed to form methane is produced by a'reaction of steam with carbon.

According to the present invention it is proposed to form methane by hydrogenating carbon under controlled temperature and pressure with or without benefit of a catalyst. The reaction can be illustrated by the previously mentioned general formula:

and for the preferred embodiment of the invention is carried on at temperatures in the general range of 1500 F. to 1700 F. and at approximately 40 atmospheres pressure or 1600 p.s.i.a. This is also within a range of temperatures that can be made useful for the production of hydrogen. Y -V v Since the reaction of hydrogen ywith carbon to form methane, however, does not go to completion at the above mentioned temperatures and pressures, that is, equilibrium conditionsk are not suchfthat all of thephydrogen gas present in the reaction zone will react with the carbon, an excess amount of hydrogen is provided. When the reaction is carried out at the above mentioned temperature and pressure, preferably the amount of hydrogen gas is increased so that about four moles of H2 are initially present for each mole of C being consumed per mole of methane produced. By this means the reaction of one carbon mole with two hydrogen moles may be maintained at the desired reaction temperature of about 1500 F. and 40 atmospheres pressure leaving two moles of unreacted hydrogen. 'I'he reaction would lbe substantially as follows:

The methane (CH4) may be separated from the hydrogen by conventional means such as a fractionator using the so-called low temperature process and made available to 'the' supply line or other collecting station. Other conventional separating means or processes'might also be used to remove the methane. If desired the separating process maybe designed to permit storage of the methane in liquid form on an adsorbant or as a hydrate following known practice. 'Ihe two moles of unreacted hydrogen (H2) are then returned to continue hydrogenation of carbon as it is fed to the reaction zone to produce more`methane. Two moles Vof hydrogen `gas are consumed inthe system to produce one mole of methane which compares with the previously discussed prior art processes in which four moles of synthesis gas are required to produce one mole of methane.

The lhydrogen gas which is used up in .the process and must be replaced to maintain the process can be obtained by using any of the commonly known systems for producing synthesis gas. However, a preferred method of obtaining hydrogen for use in this process is to reform a part of the methane produced-into H2 by the reaction- Approximately one-half of the methane produced is made immediatelyr available for pipeline use while the other half is held in the system for reforming to replace the hydrogen consumed in the hydrogenation step. This reforming step can be carried out at temperatures which are below the temperature of the hydrogenation reaction or methane forming step, and therefore, the exothermic heat of hydrogenation can be used to supply a substantial portion of the endothermic heat required in the methane reduction. Although the reaction is preferably carried out at 1300"V F. and 40 atmospheres pressure, t'he temperature may be v-aried between 1200 F. and 1700 F. and the pressure between 20a-nd 50 atmospheres or higher dependent upon the engineering requirements Ifor the specilic application.- Y

sgoogsse The complete lreaction vfrom' the ear-boli to methane; thus becomes:

Y oq-z'n-onl Jammern. 15006 r'. @.sonl-l-nloonosool -s5,545 nm. 130m r.

o+n2o o.5oni+c.5ofo2=2,97sum.

Roughly 3000 B.t.u.s are required't'o" keep' 'the system going, not counting losses. This would he' at the ra'te of approximately 6000 B.t.u. of reaction heat per mole Y of methane made available at the collecting station, which compares with the approximately 100,000 B.t.u. theoretical reaction heat per mole of methane produced which was required by some of th'e prior art methods of producing' methane. i

The process as thus generally described can take several speciiie forms, andY can hest he described' by assuming a hypothetical non-caking coal, with n'o volatiles, that' can be considered -a`s carbon and reacting according -to the equations previously given. Referring toV FIGURE 1 of the drawing, representsV the hydrogenation vessel' or chamber to which the coal is fed' from hopper 11 through line 12. 13 represents a series of coils which may be of a character such as is -found in a vertical water tube boiler and comprise the methane reduction area. In these coils is located nickell or other cata-lystfor the methane reduction part of the process. The reverse arrangement might also be used wherein the carbon is fed-` to the coils and the methane reduction takes place in the surrounding vessel. Since the carbon is in lluidized lform the rate of heat transferred through the coils 1?y shouldV be high and result in an eicient and eiective system.

`Pour moles of hydrogen from line 24 and one mole of carbon from hopper 11 are fed through line 12 into the hydrogenation vessel 10 to replace each mole of carbon being consumed in the hydrogenation process. Ash and unreacted carbon mixed therewith will =be removed from vesselY 16 through 10a -for economical operation of the process. The hydrogenation process is preferably causedl to Itakev place at approximately 1500 F. al-V though the temperature may 4be as high as 1700"v F. Only two moles ofA hydrogen are required per mole ofA carbon consumed to form one mole of methane. Consequently, :for each mole of carbon consumed in vessel 10 there is available a gas comprising one mole of methane and two moles ot unreacted hydrogen. This gas mixture is directed under 40 atmospheres pressure through pipe 14, thenpat desired conventional pressures through the heat exchanger 1S; through separatorV 17" where any tar and the like is removed and then into fractionator 18.

Fractionator 18l is of conventional construction, operating on the principle that methane and hydrogen aswell as other impurities contained in the gas mixture will condense at dierent temperatures and so may bef readily separated. Pressures as well as temperature may be varied to eiect the separation. The condensing. step is notk carried to completion, since approximately half of the methane needs to be retained in the system to provide on reduction the two moles of hydrogen consumed in the hydrogenation vessel 10. Thus, .5 mole ofmethane is collected at outlet 18a, while the other .5 mole of methane and two moles of unreacted hydrogen are passed through line 19, through the heat exchanger where the gas is reheatcd to 1200 F., and through line 2l) into'met-hane reduction coils 13. impurities such as sulphur inthe gas entering fractionator 13 are preferably collected at 18b so as not to be recirculated through the system. Itis also to be understood that although the pressure of the gas as well `as its temperature is reduced -irom the systems normal pressure of 40 atmospheres inthe `ractionator 1S for the purposes of the condensation and separation steps therein taken, this pres'- sur'e' is re-est'ablished in line 19 by suitable means', such as a pump (not'shown). It is also understood'that: any

.6 other known nieansfor removing impurities might be substituted yfor the above.

One r'iiol'e` of water intheorm? of steam enters the syst-'enr through line 20 Afor' reaction' with each 0.5 mole of methane in the reduction coil 13 toproduce two' moles of hydrogen, andA 0.5 mole of carbon' dioxide. Actually a somewhat larger proportion of steam should be added to insure completeV reduction of the methane. The exces/st` H2O" will be removed with the carbon' dioxide at 23. As mentioned previously, af slight imbalance exists between the amount of exothermic heat lgiveii oil in the hydrogenat-ion of thecoalandthe eudothermic heat required for the`V methane reduction step; 'This additional heat can be supplied by burning a small amount of the methane in the' coils' 13' with' a small amount' of relatively pure oxygeir addedy atiY 21, with a corresponding reduction .the CI-l4A available at 18u. Although the oxygen' couldVV be added in line Z0' with the steam, itv is preferred that the oxygen hev added as close to the coils 13 aspossible, so as toY confine the burning to the area where the heat equirenient exists rather than in line 20. Conce'ivably, a 'small amount of hydro-carbon IJfuel, such as butane, might be supplied with the oxygen. This Iwould avoidv lthe requirement of burning a portion of the urethaneVV to supply the" additional-amount of heat rerequired',l The products of -thecombustion plus the 2 molesof hydrogen and 0 .5 moleof carbon dioxide `formed by' the reduction of the methane exit from' coils 13 through line 2'2.v to the separator 23 where any undesired products of combustion, carbon dioxide and any water present are removed. This leaves in line 4v the two rhol'esy `oi hydrogen formed by the methane reduction reaction in the coil 13 plus the two moles of unreacted hydrogen which were not consumed in the hydrogenator 10' and have been passed through the system and thus four moles of hydrogen are available to be [fed into line I2 to continue the process. Preferably,` a super-heater 25 is provided inline 24 to bring the hydrogen gas to the desired temperature.

Although thev above system or arrangement is preferredV because sulphur from the coal will have been removed and collected at 1817 or otherwise before the gas reaches the methane reduction coil,` alternatively, if a sulphur resistant catalyst is available for use in the methane reduction zone or sulphur is not presented in the methane mixture is directly passedA via lines 114 and 120V to the methane reduction coils 113: and thenV to the fractionator 11'8 through line 122,V after passing through heat exchanger 115 and tar remover -1'1'7 As previously, the required amountsyof steam, tonnage oxygen and fuel are added through and 1211 respectively. In this instance, the methane reduction is carried only half way through completion in the coils 113, that is, only suhiciently to reduce the part of the methane necessary to produce the two moles' of hydrogen which replace the two moles of'hydrogen consumed inthe hydrogenation vessel 110. Therefore, in' this modification, there will be four moles of hydrogen gas plus a half mole of carbon dioxide and a half mole of non-reduced methane gas passing to the fractionator A1*-18A through line 112. On separation; the half mole of methane exitsto the collecting vstationV through line -118a while the carbon dioxide as well as the non-used steam and tonnage oxygenxv and other impurities are removed throughv I-18b' or in any desired manner. The remaining four moles of hydrogen gas are withdrawn through line 124 into -line 1i12 so as to be4 redirected into the hydrogenation vesse1.f110.after being reheated in heat exchanger 115 and are available to react with more carbon. t

FIGURE 3 illustrates a still further possible modification. In this instance, carbon in the form of coal is supplied from hopper 211, mixed Ywith hydrogen in line 212 and directed tothe hydrogenation Yvessel 210. The hydrogen and carbon there react to produce one mole of methane which with the two moles of non-reacted hydrogen pass through line 214 as before. The path of the gas, however, in this modification is divided so that only one half of the gas is directed through line 214a, through heat exchanger 215, through tar separator 217 to the fractionator 218 while the other half is directed through line 21417 directly to line 219 Aand into the methane reduction coils 213. Preferably a separator 226 would be provided in line 2141: to remove tar and other impurities, including sulphur. The half mole of methane Vsent to the fractionator 218 is separated from the mole of non-y reacted hydrogen and made available for pipeline use through 218a, impurities being removed at 218b. The remaining mole of non-reacted hydrogen leaves the fractionator through line 219 and Yis reunited at the juncture of line 214b and 219 with the other mole of non-reacted hydrogen and |half mole of methane being fed to the methane reduction coil 213, The latter. half mole of methane is reduced in said coils 213 to Yhydrogen by means of steam added at 220 and tonnage oxygen at 221. Thus, asin the prior arrangements, Athere will be four moles of hydrogen gas exciting from the reduction coils 2,13, which are directed through -line 222, and after being separated from the carbon dioxide, etc., by separator 223, Vare reheated at 225 and passed into line 212 to continue the process. It will be understood thatin this modification the dividing of the gas product between lines 214a and 214b can be controlled by suitable valve means or the like, and so that only the portion of methane required to be reduced to hydrogen will pass through line 21417, permitting all the methane passed to the fractionator 218 to be collected at 218a. Y

There may be instances when it is desirablerto use natural gas, propane, butane or the like as the substance for producing the hydrogen to replace that consumed in che hydrogenation vessel. FIGURE 4 illustrates a system by means of which such a substance may be utilized. In this case, coal is supplied from hopper 311 to line 3-12, as before, Wherel it is mixed with hydrogen gas directed into the hydrogenation vessel 310. After completion of the reaction, the one mole of methane and two moles of nonreacted hydrogen per -rnole of carbon consumed are directed through line 314, through heat exchange 315 to separator 317 which removes the tar and then to the fractionator 318. In this instance, all of the methane produced is separated from the non-reacted hydrogen and made available for pipeline use through lead 318a, impurities being removed through 318b as in the previous systems. The two moles of non-reacted hydrogen gas are then directed through lline 319 Ibacklto the entering line 312. mentioned previously is directed through line 327 into the methane reduction coils 313 after being heated in heat exchanger 3115. Steam is supplied through line 320 and tonnage oxygen through 321 as before. Upon completion of the reaction two moles of hydrogen and half mole of carbon dioxide exit from the coils 313 through line 322. The carbon dioxide is separated out at 323 and the two newly formed moles of hydrogen gas are added through line 324 to the two moles of the non-reacted hydrogen in line 319 to make the required four moles of hydrogen available in line 312 to mix with the coal from the hopper 311 to continue the process of hydrogenation in the vessel 310. Y v

It may bedesirable, such as during peak loads, to Are- Natural gas or some suitable substance as Y form' a higher molecular weight hydrocarbon such as butane, propane, gasoline, or the like, instead of methane. This could be accomplished in the apparatus just described with referencerto FIGURE 4 with only minor changes, as would be well known to those skilled in the ordinary coal contains volatiles which when heated result* in gases such as hydrogen, carbon monoxide and methane and other hydrocarbons in addition to tars, the major portions of which are driven off at the operating temperature of 1500 F. and may be used to further increase the yield. Accordingly, reference to hydrogen will be understood to mean a synthesis gas stream which is predominantly hydrogen. Y

If a caking coal is to be gasilied, its caking properties can be destroyed by a conventional carbonizationprocess, such as `is well known to those skilled in the art, at temperatures between 900 F. and 1500 F. and the combustible portion of the product gas introduced into the system ahead of the'fractionator and the resulting char, which is non-caking, introduced intothe

hydrogenation vessel

10, 110, 210 or 310as found in anyone of the previously discussed systems. Alternatively, the gas products could be fractionated Separately and the separated products used in the system.V The charV above referred to which remains after carbonization will consist' primarily of carbon although some residual amounts of volatiles as well as ash may remain. Nevertheless, whenever in the discussion and claims the ter-m carbon is used, it is to be understood as including such a char containing residual volatiles and ash as well as coal'.

A preferred method of destroying the caking properties of a caking coal would be by an arrangement such as is illustrated in FIGURE 5 wherein coal in fluidized form is heated in vessel 410 to 1500 F., which is suicient to drive oif the volatiles, and is kept in motion by forced circulation through

lines

428, 412 and 436' at a rate some ten to thirty times the rate at which fresh coal is fed from hopper 411. Ash is removed at 429 and the required amount of hydrogen for the hydrogenation process is introduced into the circulating system from line 424.

As an example of how the volatiles given oif by coal may be advantageously used for their enrichening effect, if 1.05 tons, are fed into vessel 410 from hopper 411, and heated through 1500 F. the volatiles which are driven oil and pass into the system through line 414 have been found to comprise roughly 13 moles of hydrogen, 5.5 moles of carbon monoxide and hydrocarbon which can be considered as the equivalent of 16 moles of methane in addition to 97 pounds of tar, leaving 72 moles of residual carbon, about 7 moles of which will be lost in the ash and exit through 429. About 260 moles of hydrogen needs to be supplied to line 430 through line 424 to combine with the remaining 65 moles of carbon in vessel 410 to provide the desired ratio of 4 moles of hydrogen for each mole of methane produced. The resulting gas product of the reaction will be a mixture comprising roughly 65 moles methane Iand 130 moles of non-reacted hydrogen gas in addition to the 16 moles of methane, 5.5 moles of carbon monoxide and 13 moles hydrogen constituting the volatiles driven olf the coal. This mixture of volatiles and gas produced from the reaction is directed under 40 atmospheres pressure through pipe 414, through the heat exchanger 415 to separation vessel 417 where the tar and other impurities are removed and iinally to the fractionator 418.

. In the arrangement illustrated in FIGURE 5 the sep.- arating step will not be carried to completion, since some portion of the methane needs to be retained in the system to provide on reduction the .two molesof .hydrogenV consumed in the hydrogenation step. In this case, '33 moles 'are required leaving 32 of the 65 moles of methanevproduced in the hydrogenation st'ep available for collection at 418a. The 1'6 moles of methane and. 5.5 moles of carbon monoxide comprising the volatiles may be also collected, making a total of 48 moles methane and 5.5moles carbon monoxide constituting the vprode uct gas,

The remaining V33 moles 'of methane and 130 moles of non-reacted hydrogen are then withdrawn from the fractionator through pipeline 419, through the heat exchanger 411'5 so as to be reheated 'to 1300 F., and to the methane reduction fcoils 413.

An excess of 60. moles -of water in the form `of vsteam enters the system at 420, and is reacted with the.33 moles of methane in the reduction coils 413 in the presence of the catalyst toprodu'ce 120 moles of hydrogen. As previously mentioned, anslight imbalance exists between theamount of exothermic heat given 'off by the hydrogenation of the Icoal andthe endothermic Aheat required in the methane reduction step. There are also supply losses for which compensation must be made. The ladditional heat Vrequirement can be satisfied, in the present example, by burning about 3 moles of the methane with tonnage oxygen provided 'at 42.1. Thus the following apprgpriatejreactions will be considered to takeY place inthe methane reduction `coils 13:

Although A'a small amount of methane is 'thus consumed in the process Vto provide the :additional amount of -endothe'rrnic heat required 'for reaction-a, the V12() moles of hydrogen produced from the 30 moles of (3H-4 in Equation -a will when added to the 130 moles of hydrogen which was not reacted during hydrogenation of the coal plus the 13 moles obtained -as a part of the volatiles in the 'carbonization step, make available a total of 263 moles of hydrogen which is more `than enough to provide the required 4 to l ratio of hydrogen to lcarbon consumed to produce 1 methane. Thecarbon dioxide and water produced are removed from the system at 4523 and the 263 moles of hydrogen continued along

lines

424 and 430 to vessel 410.

' Although the 'system a`s 'thus discussed more closely resembles that discussed with reference to FIGURE l, it should be understood that lthis was merely for convenience sake, and substantially 4thesatne 'results would be obtained if the `systein were modilied along the lines illustrated by :FIGURES Z, 3 and 4. In each instance, the equivalent of two 'moles of non-reacted hydrogen per mole of carbon consumed in the vessel 410 for hydrogenation are vpassing constantly through the system While two moles of hydrogen gas are being formed in the methane reduction coil to replace the two moles of hydrogen gas being consumed in the hydrogenation part ofthe process to forrn'said half 'm'ole of methane. 'Steam and coal a're the only 'raw Vmaterials supplied outside of the relatively small 'amount of tonnage oxygen added to balance the endo'th'erni'c heat of the methane rduction with the exotherrnic heat of hydrogenation.

The Volailles '0f Ordinary coal Will C'Ou/S-i'tlife about 20 to 30 percent 'of the heat of the coal `iii the Vform of gaseous products 'including methane as well vas hydrogen and carbon monoxide and, as illustrated 'in the example, permit minor change in the mentioned mole ratios. Not only is the hydrogen portion 'of 4said volatiles available for hydrogenatio'n purposes, -but its carbon monoxide content Emight also he converted to hydrogen 'rather than collected as a part of the lproduct gas. This could be accomplished by means of' a well known water 'gas shifting means providedV in line '422 at 431 'and connected to the steam source byline 332. Because of the additional amounts vof hydrogen Yobtained from the vola'- ties, actually only about 0.45 of a mole of methane would need to b'e converted into hydrogen.Y

Thus the .system is theoretically' substantially therm neutral. I-Iowever, there are various losses in the system for which additional amounts of heat will have to be supplied. These would include the super-heaterv 425, the generation of steam to be supplied at 420, etc.

Analyzing the system, it will be seen that asa' result of the 'several steps of de-volatilization, hydrogenat-ion, reforming and combustion that: 1.05 tons of coal. (72C-i-volatiles) +60H2O-l-6O2 yielded 'as pipe line gas' 48CH4+5.5CO, and as ylay-products The overall lbs. tar.

By estimation, the system power requirements for Vgas compression, tonnage oxygen production and auxiliaries would amount to 45.5 therms. yIf a credit of 35.8 therms were given for tar, carbon in the ash and waste heat available other than transferred within the system, then the net additional heat required to maintain the system would be about 9.7 therms per mole of methane produced. This, .when Vadded to the 1.05 tous of coal calculated .at 235 therms per ton, would give a total input into the system of roughly 256.7 therms. Then considering the pipeline gas collected to be the equivalent of 49.5 CH4 (giving 1.5 credit to the 5.5CO collected) at 3.83 thcrms per unit of CH4, therms would have been obtained so that the overall system thermal eiciency would be 190/256.5 or 74%.

In the systems described previously, the two moles `of hydrogen consumed in the hydrogenation vessel are produced by reforming or reducing a portion of the methane product except in the system according to FIGURE 4, which uses an external source for supplying the methane' to be reduced 'to hydrogen. An alternative method of gasication according to the present invention would be by a system as illustrated in FIGURE 6, wherein hydrogen is formed by the reaction of carbon with steam. The arrangement is adapted for useV with either caking or non-caking coals and' comprises a gasiiication vessel 513 which is heated to 12.00 F. and a hydr'ogenation Vessel 510 which is preferably heated, as :in the prior systems, to l500 F. to elect hydrogenation of the car.- bon to methane. As will be seen in FIGURE 6, iluidized coal or other carbonaceous fuel is continuously circulated between the hydrogenation vessel 510, and the gasification vessel 513 via connecting lines 531 'and 532, fresh fuel being added from hopper 512 into line 531 to replace the portion being consumed in vessel 510 by reaction with hydrogen supplied via line 519 and the portion being consumed in vessel 513 by reaction with steam entering via line 52.0 'to' form hydrogen. Because the fuel circulates between both vessels, the catalyst that is used for the reaction in vessel 513 must alsoA be compatible with the hydrogenation reaction in vessel 510. One such catalyst is sodium carbonate. This catalyst is ,not only eective for the gasication reaction, but will also help to increase the `formation of methane in the hydrogenation reaction. By means of the describedv movement of fuel between the two vessels '510 and 513, the exothermic heat of the hydrogenaton reaction can be used to furf nish the endother'mic heat required for the gasification reaction. The two reactions 'are illustrated by the `fol lowing formulas:

Adding `the Vformulas togethenobtains the following: zc+zH2o4 co2+cH,-6,s7o B m;

'provide' thedesired additional units of heat.

fromthe hydrogen producing vessel 513 through line 522. The `carbon dioxide is removed at 523 and the two moles of ihydrogencontinued to line 519 where they combine with VVthe two moles` of unreacted hydrogen fromthe fractionator 518 and are heated inV heater 525 and thence fed into the hydrogenator 510. As in the previously discussed systems, according to FIGURES 1 Vthrough 5, the gas exiting from the hydrogenation vessel 510 comprises one mole of methane and two molesof unreacted hydrogen for each -rnole of carbon consumed therein, plus volatiles, and is passed via line 514 through the heat exchanger 515 to the separator 517 where tar is removed, and thence to the fractionator 518. The methane is` removed for collection Vthrough line 51841 and the remaining two moles of unreacted hydrogen returned to the hydrogenation vessel 510 after being reheated in heat exchanger'SlS.

v In analyzing the system, it has been found that 94,200

i B.t.u. will be consumed in preheating the reactants and producing oxygen and compression, Vfrom which 40,200 B.t.u. may be subtracted for available waste heat, making the net requirements of the process 54,000 B.t.u. or the equivalent of .32 carbon mole. 'Ihis added to the 2.25 consumed in the reactions to produce a mole of methane, gives` a total of Y'2.57C'or 4.36 therms as the net input ofthe system. .75 therms are added to this kligure for auxiliaries making the gross fuel requirements per mole of methane amount to 5.11 therms. Considering'that the output of the system -is one mole of methane or 3.83 therms, then the overallefliciency be j Y or 75% Y `Since both reactions involvecoal `or other .carbonace'ous solid'fuel and utilize'sodium carbonate as acommon catalyst, conceivably'the two reactions might take place in the same vessel or chamber. Such an arrangementisillustrated by FIGURE 7. In this system, coal is supplied from hopper 612 through line 611 and line 633'toaiv'essel 610. Water in the form ofV steam, and tonnage oxygen for combustion purposes, is Vfed through line'620, valve 635, line `634- and line 633 into said vessel' 610while hydrogen issupplied to the vessel 610'through Y line 619, `valve 636, and lines 4634 and 633.

Valves

636 and 635, respectively, may be operated so that during one alternate period of time, hydrogenwill be fed into vessel 61'()V to react with Vthe carbon fuel to produce methane andjin Va second alternate period so thatwater in the form of-'steam will be supplied to the vessel 610 to produce hydrogen to replace that consumed lduring the first mentioned period. Thus the following two reactions will alternately take place in said vessel 610:

(l) C+2H2O 2H2+C0239,000 B.t.u. K (2) C+4H2 CH4+2H2+32,57O B.t.u.

tion Al 'and the' one mole ofrnethane' and two remaining Ymoles of unreacted hydrogen of'Reaction 2 will o f course- Yexit as the product gas of vessel 610 through Yline 61,4

The reaction of carbon with the hydrogen is'exothermic` and continues until the temperature of the carbon reaches approximately 1700 F.7while Vthe reaction of the carbon with steam to produce the hydrogen consumed is enl dothermic and lowers the temperature from 1700 FQ to 1500 F. so that the process may be considered as continuous and in balanceY except for the additional 6,500A

B.t.u. of endothermic heat required in Reaction 2.' This; however, can be supplied by adding tonnageoxygen with the steam and used to burn carbon as in the arrangement according to FIGURE 6.

As a further modification, the steam and hydrogen may be mixed in related proportions, so that the reaction of carbon with the hydrogenV to produce methane and the reaction of carbon with steam tok produce hydrogen may take place simultaneously in said vessel 610.' Tonnage oxygen also be supplied to burn a. portion of the carbon as in Ythe previous systems.

Asa further alternative, two vessels may be utilized as in the arrangement according to FIGURE 8. In this system carbonaceous solid fuel is supplied from hopper 712 through suitable lead lines 711V and 733 to vessel 7110 and through leads 7L1a and 73311 to 'vessel 710a.

' Steam is'supplied to vessel 710 via line 72.0, valve 735,

and lines 734and 733 and to vessel 710a fromline 720 via valve 73511, lines 73411 and 733a. Hydrogen is also supplied to each vessel Yfrom line 719 passing to vessel 710 via valve 736 and line 733 and to vessel 710a via valve 736a and lner73v3a.v Thus the valves may be operated so that while hydrogen is being fed to vessel 710, tonnage oxygen and steam is fed to vessel 710a and then in the reverse. Thus 'while hydrogenation of carbon to' methane is taking place in one vessel, hydrogen is being newly formed in the other vessel so that there will be a' substantially uniform rate of removal of methane from the fractionator.

, H a Both the vtwo moles of hydrogenpproducedv in' Reac- If desired, the coal may be fed to the respective vessels only during the hydrogenaton part of the process, the coal remaining in the -vessel then being used for the reaction of steam to form hydrogen. In this way fresh coal is always available for the reaction-with hydrogen. Also there is no problem of providing additional heat to cornpensate for the cooling-off eiect of the added coal in the hydrogen forming step.

Obviously, many further modifications and variations of the invention as hereinbefore' set forth Vmay be made without departing from the spirit and scope thereof, and it is to be understood that the above description Vis not to be taken in a limiting sense, but only as illustrative of my invention. For that reason, only such limitations should be imposed as are indicated in the appended claims. Having described my invention, I claim:

1.,In a process of manufacturing pipeline quality gas, the steps comprising arranging two reaction zones in direct heat transfer relation; reacting hydrogen with carbonaceous solid fuel in one zone in the presence of an excess amount of hydrogen to producemethane at a temperature and pressure which-produces a product gas consisting essentially of methane rand hydrogen; reacting methane with steam in the other reaction zone, at a temperature below the temperature in said one zone, to produce hydrogen in suicient quantity to replace the hydrogen being consumed in the first zone; the available exothermic heat from the first reaction zone being utilized to supply to said other reaction zon'e'at least a substantial part of the endothermic heat' required to produce hydrogen; separating out at least a portion of substantially only the methane which Vis produced in the first zone, collecting the same and returning the excess hydrogen to the first zone for refuse in-the process, together with the hydrogen producedinsaidiother zone.'

2. Ina process of manufacturing pipeline quality gas, the steps comprising maintaining tworeacton zones in direct heattransferlrelation, feeding volatiles-containing carbonaceous solid fu'el and hydrogen to a lirst zone',

driving oft volatiles including hydrogen, carbon monoxide and methane while reacting the hydrogen with the residual carbonaceous material at a temperature in the range from approximately 1500 F. to l700 F., and at a pressure in excess of approximately 40 atmospheres to form a product gas consisting essentially of methane and unrecated hydrogen; separating out a portion consisting essentially of methane; returning the unreaeted hydrogen to said rst zone; in the second zone, at a temperature above approximately 12.00 F. but below the temperature in said first zone, reducing a portion of the unseparated methane to produce a sufcient amount of hydrogen to replace the hydrogen consumed in the first zone; utilizing the available exothermic heat of the'reaction in the first zone to supply to said second zone at least a substantial part of the endotherrnic heat required to produce hydrogen therein; andreturning the newly produced hydrogen to said first zone.

3. ln a process of manufacturing a pipeline quality gas, thestepscomprising maintaining two reaction zones indirect heat transfer relation, feeding carbonaceous solid fuely to one reaction zone; there reacting hydrogen with the carbonaceous solid fuel to form methane in the presence of an excess amount of hydrogen at al pressure and at a temperature in the range from approximately 1500 F. to 1700 E. which produces a product gas consisting essentially of methane and unrecated hydrogen; removing the product gas from said reaction zone and feeding it to the second zone; supplying steam to said second zone to reduce a part of the methane to hydrogen while utilizing the available exothermic heat of the reaction in the rst zone to supply at least the greater portion of the endothermic heat requirement of the methane reduction step conducted in said second zone, a sufficient proportion of said methane being reduced to hydrogen in said second zone to replace that consumed in the first zone; then separating out the remainder of the methane from the product gas, collecting said separated out methane remainder and returning the unrecated and newly formed hydrogen to the first reaction zone to continue the process.

. 4. ln a-process of manufacturing pipeline quality gas, thesteps comprising maintaining two reaction zones in direct heat transfer relationffeeding carbonaceous solid fuel to one zone; reacting hydrogen with the carbonaceous solid fuel in said zone at a pressure and at a temperature in the rangeY from approximately 1500 F. to l700 F.l to formV methane in the presence of an excess amount of hydrogen which produces a product gas consisting essentially of methane and unreacted hydrogen; removing a portion of the product gas embodying a mixture of unreacted hydrogen and methane to a second zone; utilizing the available exothermic heat of the reaction inthe firstV zone to supply at least the greater portion of the endo'- thermic heat required in said second zone and reducing said methane in said second zone to hydrogen at a temperature below the temperature in said first zone, the portion of the product gas removed to said second zone being suiiicient that the hydrogen resulting from the reduction of the methane of said portion will equal that being consumed in the first zone; separating out the methane from the remaining portion of the product gas and returning the unreacted hydrogen of both portions of the product gas and the newly formed hydrogen to the firstv zone.

5. In a process of manufacturing pipeline quality gas, the steps comprising maintaining two reaction zones in direct heat transfer relation, feeding carbonaceous solid' fuel into one zone, there reacting said carbonaceous solid' fuel with hydrogen at a pressure and at a temperature in the range from approximately 1500 F. to 1700" F. to form methane, more hydrogen being present in said zone than is reacted, which produces a product gas consisting essentially of methane and unrecated hydrogen; removing the product gas from said rst zone; separating out the methane as the desired product, and returning substantially all the unreacted hydrogen to the first zone;

reacting hydrocarbon with steam insaid secondzone at a temperature below that in said first zone to formhydrogenand other products, utilizing-theavailable exothermic heat in therrst zone to supply a substantial-portion of the endothermic heat required in said second zone, the hydrogen so formed'beingtused to replace that consumed in the first zone.

6. a process for the manufacture of pipeline quality gas from carbonaceous solid fuel -by the reaction of carbon with hydrogen to produce methane; the improvement' which comprises, in a first reaction, reacting hydrogen with carbonaceous solid fuel in the presence of an excess amountvof hydrogen to produce methane a-t a temperature and pressure which produces a gaseous productV consisting essentially of methane and unreacted hydrogen, said reaction being exothermic; separating out from said gaseous product a partcomprising pipeline quality gasy consisting-essentially of methane, and collecting said part for pipeline gas use; returning essentially all the unreacted hydrogen -to said reaction; in asecond reaction, reacting steam' with an ingredient selected from the group consisting of carbonaceous solid fuel and hydrocarbon to produce additional hydrogen in amounts suicient to maintain the process in operation;4 said second reaction being endothermic, so controlling the pressure and temperatures at which the two reactions are caused to take place that only a slight imbalance exists' between the amount of exothermic heat `givenoif in' the rst reaction and the greater endothermic heat requirements of the second reactionythe two reactions being conducted at a temperaturev gradient-which permits a transfer of heat from theexothermic first reaction to the endothermic second reaction, and continuously maintaining the heated-V solids of the first reaction in direct heat transfer relation with the zone in which-the second reaction takes place so thatl said exothermic heat of said rst reaction is usedto supply all but a relatively small proportion of the endotherrnio requirements of the second reaction.

7. In a process according to claim 6 wherein carbonaceous solidfuel is reacted with steam in a gasification zone at a ytemperature between 1200 and l700 F. and pressure suiiicient toV effect therein a useful steam conversion to hydrogen,- wherein carbonaceoussolid fuel 4is concurrently reacted with preheated hydrogen in a hydrogenation zone at a higher temperature in the range 1500 to 1700 F. and at-thefsame pressure, wherein said hydrogenation zone is maintained at an average temperature above that of said gasification zone, andwherein a direct transfer of heat is 'established between the two zones by continually transferring carbonaceous solid fuel from said hydrogenation zone to said gasication zone while transferringcarbonaceous solid fuel from said gasification zone to said hydrogenation zone, whereiny gaseous reaction products are lrecovered from said` zones, wherein gaseous reaction products are recovered from said zones, wherein substantially all carbon dioxide and other undesired impurities are removed therefrom,l wherein there is recovered from theiresidue of said gaseous reaction products a high Btu-content product gas of pipeline quality consisting essentially ofmethane, and the remainder of said gaseous reaction products is recycled as substantially pure hydrogen gas at an elevated temperature to said hydrogenation zone.y

8. In a process according toclaim 6 wherein steam is passed upwardly through a gasification zone containing finely divided reactive carbonaceous solid fuel maintained at a pressure near 40'atmospheres Vand a temperature sufcient under iluidizedk reacting conditions to effect therein a useful steam conversion to hydrogen, wherein preheated hydrogen gas is concurrently passed upwardly through a hydrogenation zone containing finely divided reactive carbonaceous solid fuel maintained at a pressure near 40 atmospheres andV at a higher temperature in the range of 1500 to 1700 F. under uidized reacting conditions, said 15 temperature in said hydrogenation zone being higher than in said gasification zone, wherein gaseous reactant products` Yare recovered from said gasification and hydrogenation zones, and substantially all carbon dioxide and other undesired impurities are removed therefrom, wherein the residue of said gaseous reactant products is separated into a substantially pure hydrogen gas and a high B.t.u.content product gas of pipeline quality consisting essentially of methane, wherein the high Btu-content product gas is collected and said substantially pure hydrogen gas is recycled at an elevated temperature to said hydrogenation zone, and said carbonaceous solid fuel is circulated between saidV zones Vso that the carbonaceous solid' fuel moving from said hydrogenation `zone is hotter than carbonaceous solid fuel moving from said gasification zone.

9. In a process according to claim 6 wherein the additional-hydrogen required to maintain the process in operation is obtained in the second reaction by the reaction of carbonaceous solid fuel with steam.

` 10. In a process according to claim 6 wherein the additional hydrogen lto maintain the process in operation isY obtained in the second reaction by the reaction of carbonaceous solid fuel with steam, and the balance of the endothermic requirements of saidsecond reaction is supplied by reacting relatively pure oxygen with a portion of the carbonaceous solid fuel.

11. In a process according to claim 9 wherein the carbonaceous solid fuel used is partially reacted fuel from the first reaction. H e

12. In a process according to claim wherein the carbonaceous solid fuel used is partially reacted fuel from the first reaction.

' 13. In a process accordingto claim 9 wherein a single :atalyst is used for accelerating` the two reactions.

14. In a process according to claim 9 wherein sodium carbonate catalyst tions.

15. In a process according to claim 9 wherein the two reactions are carried on in separate reaction zones and the two zones are so arranged as to permit transfer of the carbonaceous solid fuel from one to the other, and fresh carbonaceous solid fuelis fed into the system by mixing it with the partially reacted fuel proceeding from the second reaction zone to the first reaction zone.

16. In a process for the manufacture of pipeline quality gas from carbonaceous solid fuel Aby the reaction of carbon with hydrogen to produce methane, the improvement which comprises, in a first reaction, reacting hydrogen with carbonaceous solid fuel in the presence of an excess amount of hydrogen to produce methane at a temperature and pressure which produces a product gas consisting essentially of methane and unreact'ed hydrogen,

ysaid reaction being exotherrnic, lremoving said product gas, separating out pipeline quality gas consisting essentially ofrmethane from saidremoved gas, and collecting the same as a product, returning essentially all the unreacted hydrogen to said reaction, in a second reaction, reacting'steam with an ingredient selected from the group consisting `of carbonaceous solid fuel and hydrocarbonV to produce additional hydrogen in sufficient quantity to maintain the first reaction in operation, said Vsecond reaction being endothermic, Vso controlling the pressure and temperatures at which the two reactions are caused to take place that only a slight imbalance exists between the amount of Ythe exotherrnic heat given olf in the rst reaction and the greater endothermic heat requirements of the second react-ion, the two reactions being conducted at a temperature gradient which will permit a transfer of heat from the'exothermic first reaction to the endo-y thermic second reaction, maintaining .the heated carbonaceous solid fuel of the iirstV reaction in direct heat trans- -fer relation with the zone in which the second reaction takes place so that said exotherrnic heat of said rst reacis used for accelerating the two reaction supplies all'but a relatively' small portion of the endo- ,175

therniic .requirements of the second reaction, and supplying the balance of the endothermic requirements of said second reaction by reacting relatively pure oxygen with a portion of the materials in said zone which are undergoing reaction to produce the additional hydrogen.

17. In a process -for the manufacture of pipeline quality gas from a carbonaceous solid fuel by the exotherrnic reaction of carbon ywith hydrogen to produce methane, the improvement which comprises, in a first reaction, reacting hydrogen with carbonaceous solid fuel at near 40 atmospheres of pressure and at a temperature in the approximate temperature range of l500 to 1700 F. which produces a .gaseous product consisting essentially of methane and unreacted hydrogen, separating out a port-ion therefrom of pipeline quality gasconsisting essentially of methane and collecting said portion; in a second reaction reacting steam with an ingredient selected from the group consisting of carbonaceous solid yfuel and hydrocarbon ata pressure near 40 atmospheres and at a temperature in the approximate range of 1200 to 1700 F., but a temperature less than the temperature of the first reaction, which produces hydrogen in amounts sulficient to replace that being consumed in said first reaction; and maintaining the heated carbonaceous solid fuel of the first react-ion in direct heat transfer relation with the zone in which the second reaction takes place so that the exotherrnic heat of the first reaction is transferred to the reactants-of said second reaction which supplies the major portion of the endothermic heat requirements for said further reaction, and returning the unreacted hydrogen and the newly formed hydrogen to said reaction zone to continue the process. I

18. ln a process of manufacturing pipeline quality gas, the steps comprising simultaneously conducting two reactionsV in direct heat transfer relation, in one of said reactions, reacting Ihydrogen lwith carbonaceous fuel 1n the presence of an excess amount of hydrogen Yto produce methane at a temperature and pressure which produces a product -gas consisting essentially of methane and hydrogen; in the other of said reactions, reacting a material selected from the group consisting of carbonaceous solid fuel and hydrocarbon with steam to produce hydrogen in suicient quantities to replace the hydrogen being consumed in the first of said reactions, lconducting the two reactions at a temperature gradient which permits a transfer of the available exotherrnic heat from said first reaction to the second reaction which is endothermic, the temperatures and pressures at which the two` reactions are conducted being so related that the said exothermic heat of the first reaction supplies a substantial part ofthe endothermic heat required by the second reaction to produce hydrogen, separating out at least a portion of substantially only the methane which is produced in said first reaction, collecting the same as a product gas of pipeline quality, and returning the excess hydrogen together with the hydrogen producedrin said other reaction to the hrst reaction for continuance of the process.

1'9. In a process of manufacturing pipeline quality gas, the steps comprising'arranging two reaction zones 1n direct heat transfer relation,'feeding carbonaceous sohd fuel and hydrogen :into one zone, driving olf volatiles while react-ing hydrogen with the residual carbonaceous fuelV in the presence of an excess amount of 'hydrogen' to produce methane at a temperature and' pressure which produces a product gas consisting essentially of methane and hydrogen, continually circulating said carbonaceous fuel into and out of said one `zone and adding fresh carbonaceous fuel to said circulating fuelrto replace that being consumed in the reaction with hydrogen, collecting said product gas, reacting a portion of the methane of said product gas with steam in the other reaction zone, at a temperature below the temperature in saidrone zone, to PrQtlll hydrogen., reacting carbonmonoxide present in 17 18 the system with steam to produce hydrogen, the amounts References Cited in the le of this patent of hydrogen .thus produced heing sutcient to replace the UNITED STATES PATENTS hydrogen being consumed -1n the first zone, the available exothcrmc heat from the first reaction zone being 1,209,258 Brfdley Dec' 19 1916 utilized to supply to said other reaction zone at least a 5 2,634286 Elhtt API" 7 1953 substantial part of the endothermic heat required to pro- 2,654662 Gon Oct' 6 1953 im hydmgen therein Separating 01 at lea a mi@ 33335123 111122112111111 'lie i',

of substantially only the methane which is produced in the first zone, collecting the same, and returning the hydrogen of said product gas together with the newly formed 10 FOREIITT PATENTS hydrogen, to the first zone to continue the process. 522,640 Great Brltaln June 24, 1940 corrected below.

UNITED STATES PATENT. OFFICE r CERTIFICATE 0E CORRECTION Patent NQ. 3.!004V839 October 17V 196-1 Earl Tornquist It is hereby certified that error appears in the above numberedpetent requiring correction and that the said Letters Patent should read as Column I3,- Iines 6. 2T., e9 and 72XI for "unrwawav#n each occurrenceg,V #rea-Lg-YY unreacted -3 column 14Vl lines' 54 and 55g strike out "wherein g'seous reaction products are v recovered from said 'zones Signed and sealed this 3rd day of April 1962 (SEAL) Attest:

ERNEST W. SW'IDER DAVID L. LADD Atteting Offier Commissioner of Patents

Claims

1. IN A PROCESS OF MANUFACTURING PIPELINE QUALITY GAS, THE STEPS COMPRISING ARRANGING TWO REACTION ZONES IN DIRECT HEAT TRANSFER RELATION, REACTING HYDROGEN WITH CARBONACEOUS SOLID FUEL IN ONE ZONE IN THE PRESENCE OF AN EXCESS AMOUNT OF HYDROGEN TO PRODUCE METHANE AT A TEMPERATURE AND PRESSURE WHICH PRODUCES A PRODUCT GAS CONSISTING ESSENTIALLY OF METHANE AND HYDROGEN, REACTING METHANE WITH STEAM IN THE OTHER REACTION ZONE, AT A TEMPERATURE BELOW THE TEMPERATURE IN SAID ONE ZONE, TO PRODUCE HYDROGEN IN SUFFICIENT QUANTITY TO REPLACE THE HYDROGEN BEING CONSUMED IN THE FIRST ZONE, THE AVAILABLE EXOTHERMIC HEAT FROM THE FIRST REACTION ZONE BEING UTILIZED TO SUPPLY TO SAID OTHER REACTION ZONE AT LEAST A SUBSTANTIAL PART OF THE ENDOTHERMIC HEAT REQUIRED TO PRODUCE HYDROGEN, SEPARATING OUT AT LEAST A PORTION OF SUBSTANTIALLY ONLY THE METHANE WHICH IS PRODUCED IN THE FIRST ZONE, COLLECTING THE SAME AND RETURNING THE EXCESS HYDROGEN TO THE FIRST ZONE FOR RE-USE IN THE PROCESS, TOGETHER WITH THE HYDROGEN PRODUCED IN SAID OTHER ZONE.