Thermodynamic Textbook 1

8/6/2019 Thermodynamic Textbook 1

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THERMOD]TNAMICS OF GASIFICATION REACTIONS 81

CHAPTER 3THE THERMODYNAMICS OF GASIFICATION REACTIONS1. Introduction

The gasification of solid fuels features a number of high_temperature proces^ses. It may therefore be expected that,under a given set of conditions, the composition t th. g""formed will largely be determined by the equilibriumposition between a complex series ol reactions. At thesame time, the gas composition will be closer to equili_brium the higher the temperature and the longer th resi_dence time in the reaction zone.The ash content of coal and other sotid fuels a16o plays asignificant part, since its common constituents (iron-oxidel"d.L129S) are catalysts for gasification reactions.rrqurllrrum is established especially quickly in contactprocesses such as the important reaction for the conversionof carbon monoxide by steam, This reaction, of course,often determines the concentration of the basic comporr"rrt"in the gas produced in gasification processes. calculationsof equilibrium compositions enable one to obtain a prelimina_ry idea of the effect of air-supply composition, temperatureand pressure on the course of a proposed process.A study of the tables of values for the thermodynamicfunctions used in calculaflone for gasification proceaseshas shoq'n that much of the baeic Jata are obsolete. Theuse of such data may lead to large discrepances betweencalculated values and practical results it may also tend toundermine confidence in applying thermodynamic analysieto gasification processes,'Wagman, Pitzer, Rossini et al.t1l studied thethermodrnamics of gaeificati?eactions in 194b. The

o4.

All reactions associated with the gasification proeessmay be divided into three categories:A) Oxidation of carbonc+ or: co?cf o,-co

4(,o* o o: co"c + co,:2co

B) Oxidation of carbon by steamc+HrO:co+H,c + 2H,O: co + 2H,CO+H,O: COz * HzFr2o: H2+o,

H,o:+H,+oH'i The physical constants have now been defined with theutmost precieion (see ref. Z). This has actually incurredno significant modification of their values.

80


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8382c)THER,MODYNAMICS OF GASIFICATION REACTIONS

Diseociation and conversion of methaneCHo:C-t-21,

CH4+Cor:2CO+2H,CH4 + H,O: CO + SIJ,

cH4 + 2H,O:cor+ 4H,.The preceding list exhausts a1r the urtimate reactionswhich have been considered anywhere in connection withthe gasification process. In practice, each of these

It is recognized that the reactions of interest here maytake place over a temperature range from several hundreddegrees up to 2000oC. However,ln view of more recentinterest in high-temperature proceases (such as gasifica_tion in oxygen and the partial thermal oxidation oi methane),we have included in our tables rerevant data for these moreextreme conditions. It may be noted that one of ourcolleagues [4] adopted a temperature of BoOOoK in order toa used a wide range ofo reaction of the products: O out the thermodmamic3. Results of Calculations

THERMODYNAMICS OF GASIFTCATION REACTIONSequation

Rln.Ko:-+*a*rur v ar-ous Liaglllcatron taeactions

4.

Expreseions for the equilibrium constants, in terms ofthe equilibrium degree of conversion, are given in Table 22.calculation of the concentration of a given component inthe equilibrium mixture is obtained from the formula

n,.70{)s_ _InJ ,where n. ie the number of gram molee of the , _thcolnponent, n, is the total number of moles in the syetemand g, is the concentration of the i -th component in theequilibrium mixture (per cent by volume).

The resulte of calculation of the degree of convereionand concentrations of the componenta in the gas mixtureare given in Tables 2B-Zg.Our calculated valuee of g,(n, Ko, AHf and AZ f.or aIIthe above reactions are given lir tUtes 16-Bb. As wasobserved in Chapter 2, thermodrnamicproperties of the comp in gasificationreactions are known to accuracy; wetherefore calculated al using the


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84 THERMODYNAMICS OF GASIFTCATION R,EACTIONSTABLE 16

Logarithms of the equilibrium contants for combustionreactionsc+co,:2co

THERMODYNAMICS OF GASIFICATION REACTIONS 85TABLE 17

Logarithms of the equilibrium constante for reactionethe oxidation of carbon by eteam for1.R II,O-Ort++1/,rr,

298. t6300400s006007008009001000110012001300L4oo15001600170018001900200021002200230024002500260027002800290)3000

89.09168.66751 .53747,25734.41229.50225,82622.96520.675f3.80077,23715.91414.77913.79512.93312.18011.49610 8901().?,4l9.849.4028.99r8.6128.2687.9477. 6507 .177u,fu

23.90719. 10716.23314.318r2,94471.971.11.1041 0.4569.922I .4759.0958.767E.4818. 2308.0067.8067.626

I .:Li 317 .1797.0546.9386.8316. 7336. 63C6.47t6.;i95

45.0644.78032.43r25.02.t20.08516.55813.91511.86010,2198.8787.7626.8186.0125,31.44.7044. 1633. 6903,2642.8812.5362.230

1 .0381 .6761.436t.215t.0750.7820. 6450,/t81

-21 .038-20.85r-1D att-8.792-5. 769-3. 614_2.004--{. 756l-1).2371 .0457.7132.2772.7563. {683.5263.8404.11t)4.3624.582/t.7784.95{j5.7165.2625.i19;5.5165.6205.82()< o{ !

298.1ti3004005U)60cl7008009001000rrcj1200130()74001 500160017o()1800l90r)20002to0220C)230024U)25U)260i,27C)028002900?,u)o

-76.()21-15.88(J-10. t34-8.614-4.318-2.641-1.379-o.\tt0.3931.038t.i7t2.02!t2.418

3.04ti3.3043.7383.9194.0834.2314.3664.4894-ffiz4.7M4.8004.8874.9685.M?,

-Ll .()0:'-10.9()i- 6.94i-4.i17-2.8f)(j-7.i67-0.7i:)-0.()34).r481 .()311.437I .78r2.08()2.3?,92.5662.72.9483.1103.258?.5073.6163.7163.8083.8923.9714.04?)4.7714.773

5.C)t64.972J.1882.1?,71.4510.97 40.6250.?,61().1i$

-(,.ry)1-().138-r).247-o.3:'-o.41i-0.48()-0.536-0.58-0.62-0.663-0.696-O.i21t-o.710-0.773-4.794--4.812-0.829-0.844-0.858-0.87r)

-40.()5()-i19.78()-2t.242-22.qnA-18 (t?,4-l it.itSlt_1:1.290_11,49r)- 10.()6:i- 8.883- 7.8r8- 7.()$/L- 1.72it- -r.78()- 1r.0994.270- 3.886- 3.540- 3.229_ 2.943- 2.2- 2.443- 2.223- 2.()ZO- 1.832- 1.6t7- 7.49t

-45.475-.13.0:l:)-. l:A-2().88t-17 .:{.jg-74 .777_11 .(tt)(j- t.ii:)- 8.(i:i:)- 7.(i84- (i.87t- 6.1(tl- i.i17- i.(f)t- 4 ':tt(t- 4.()gl- x.f.)()-:.()12- 2.7|(i- 2.a:/)- 2.197- 1.(t7(t- |,i)B- t.:t77- L.2ti


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86 THERMODYNAMICS OF GASIFICATION REACTIONSTABLE 18

Logarithms of the equilibrium constants for reactiona forthe dissociation and conversion of methanetCIl.+21,,(i --co+41I:


Heats of combustion reactions (cal/moe)c+co" tco

298. i6300400500600700800fJ0( )

I {,01)'l Ir)l)l-{IrI i0(t14it)l,:r( l0id)()I 7(X)18r il)I 9()rl0(n )It0r)ll()( ):.:: tr )021U0:i00:600,-70028002900i00()

-8.839-8.815-5.498-2.UN)-0.952-0.167+{}.491l.()(llI.4381.782.10!2.:"(i72.1972.7982.97t)3.13tr:l.27tjf,.4rl'li, 5 lJ3.6221.7 t8i.816'i.88(j:i.c6r)4.()2J4.092.1. t,) !4.207

-29.030-29.6)9--18.822-12.219- 7 .76!)- 4.56- z.til-0.2$1.27b2.48'3.5t t

5.t24.7 $Jb.:J24fi.8l;7.25()7.638i .9,3;8.2978.1-1788.83/tf,. (J78I 28r9.4169. 6579.8249.9781().120

-24.921)-24.(ilt-|i.632-10.082- t;.318- :1.5t2- t.tzi0.091.4012.475

4.131t4.7855. ;J505.844$.2796. t667,0727. 601L .18.0848.30t8.4888.6648.8288. 98()s.1209.250

-19.90/t-19.291.- 7.944-487- 2 (iy)- 0.-90u0.4571.J/2.4673.8804.936. o{5.7 476.083tj 3866.65C6.907.1297.5327.6947.8527.C998. 3168 2628. 380

()2C84005006007008009rl0100fr

110( )12( }{Jl30llI4L{)1;0(l16rI7( 0l80r)19011:l0r){iI 10.)?l()(r130(1?10015r,)26001700tRnr?90( r30([)

-93965-91052-.91069-fi4090-s4t28-97176-9!227-9428-911331-9438 r-914",tt-94778-94529-9458{l-940J1-94693-9475 r-9481t-c4872-9/{939-95010-95086-9516?-952\2-95331-95423-95519-95622-957:7

-:1720c-201r15-6317-26294-.641-2623-2664-26779-2692r-270tj8_r1rrL-27386-27736-27903-28084-28269-28456_:8646-2884t-29043-2945/+-29664-29882-30'103-3032-30553

-6767-b/bJ-ti7752-779-677911-rj7760--67705-u, bi'4-67552-67460-67362-s725;-6714!r-6ri9l8-66789-06668-6042-66416-66291-66109-66042-65909-05787-boob-65540-641j-65298-6 183

3956112211t!435Ltsjl41182409884077340539402944003139783917 tilgl92i888r38581ii/i796037tt1369993666i,]OJJ360013i656ts7312349733462r

* The thermodynamic values for methane at temperatureafrom 1500 to 3000"K are those calculated by us.LJ


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88 THERMoDYNAMICS oF. GASIFICATIoN REACTIoNSTABLE 20

Heats of reactions for the oxidation of carbon by steam(cal/mole)

THERMODYNAMICS OF GASIFICATION REACTIONSTABLE 21

Heats of reactions for the dissociation and conversionof methane (caUmole)?"..f(

89

"K H:O-OH++'./"H, CH.+2H-O--co=+i-q,0:08. r6100

5Otl0clo70r)80090010001t001200130014001500I 60rl17001800190020002100

22AO230024002500260027003800t900300

'1990231382319793116:l3:29:il43l3245532443213!323913:318312503tr632i.i3r9 r831?81)316291+O313r631141309603077330571303830201:9950:073

2023911543220t1Jla I:2867235682387424t372{392457424751,248982502625202252522528625298253052;30425283214625104250902493921840

-9663-9839-9712-9522-9295-9054_8807-8557-8318--8085_7860-7840-7430-7224-7027-6.342-6666-u94-6177-6012-5858-5705-5560-542a-5276-5111-5017-4890

5710257799580395827484975876s8898JVU/ /59f3ri937559502ir9618-97lt*5980398815994760001600486008560t22601s76018460204602276024460264602746028160283

G550066254660466728669297100$7257673920705676026768967758678176783679t06i972679646797667982679856796C679:1678S678 r6

0298.16400)0\)ti0070080f)9r'i)10[fJ1lrxjl?[r.)

1?,0l4qt)l5u rIt-r,lli i.t )16r- ill)it,t2t N-ttt2l()tl22U.13rO2|t_[.t23(-tt_t26(r t27(rI23r -r2Etjr:0

r5987178891862813303r 990r24122083821182zr+t2 I 66{Jz 1817219?,822.!i2208822 13122t55'2r5t22L3rt22t 162itg'o2?t:9z ri)22t'2\21961lt.urfi\

i552591 l060053608046 13i86 176202021i062224621996t11161grjfl61781jLlJii!6131;610{t6ti7 4!E0t2t.trr_l1r r{9117994-.r8i3158378Jsl?3i6fi1:ttrsUOJJ

{88949271503 1-cf2825206352i2eizz5?6135390r41q15t2ili432954'!9t5i199i4(t16J31:)-5.lfi,j!t?,i325 )23.j5)q'295251S,51163lll I5 I rjr:i

?e22(t4i.'(j3g1tti)421()84t6iE'14tutj{5(r;S4558846(rtg4639116897692:"4711L42t'g41:h17 I lt)41 4121t 1J.)112Ii318ir1 t6i41 1t2lit_ti2{fi6[titi8

CO+H,O- I-co,+H, lHro-H:+l/roj cH:C+2Hr cH+H!O:CO+


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90 THERMODYNAMICS OF' GASIFTCATION REACTIONSTABLE 22

The free energies of combustion reactions (cat/moLe)

THERMODn{AMICS OF GASIFICATION REACTIONS 91TABLE 23

Free energies of reactions for the oxidation of carbonby steam (caI/me1s1H!O-OH++r/.H!

2CO-C+Co,298. l0{005006Ctoi(08Cr.)90010r'ot 10()1200l3orjl40t)100

16Cr(,170(lE00lc0{)2r rl02 t00230(J23(li,f10( |lit t'lrjlJrl::170{.1:.:80i-.it/r)Ll:i'.nlrl

-e 429-9{316-938-94445-94 94_o4iti*c570-9499-c46!4-9{64-94659-tt46i!-..t!6if)-9468;-91088-tr{83-9{678-0{667-0160-9{6{(l-942i-9159r,-c 157;J-t\3i:-91 lt'-cll;;-91t;-c 1t)1.,1

-2781-34070-3713',i-39204-432-tai42-478r:8-49gtil-ZUrLl-a1 t: t-o6100-18244-6020-62278-4293-663(r0-68298-7(.,?8tj- ji-11233-7t 19!L-78 t 45-8r),184-qtD?-83953-85870-87781

-61480-.59356--72O-55140-3034- 50935-442-46?58-71?82-426t9-4u58-38510-36{6fJ- J+q,t- :.1?9-3039r- 28377-!6369-:113?-223i8-20392- 1840- r0127- 14458-1248i-10524-J tiJ-66rr0

28700:11386rl 14l;838I 1;76I,1i31 11- 1083

- g{tr8-13;142-176i3-!rla)-35814-:9868-33902-37823-1\929-45915-+Y-384rJ-i7789-617f 8-6rit-69537-7J{:9-77i1i-84173

-287_2L-20rM-15838-n76- t- lugii520850b

17t;:)!l t:r.t281 I2386339(.t23781:)4ltJ2l.t45il;498838lt.t5778i.r6171b056:6693773!2977\D.-t81 17:l

{J:93.16100;cn000700gr)9,ltll00f

1 l0f)lru130(lI lljr-lI r.I_l6l)ol ?rrl8t-l1fjo,j1r illr-lJlrIt2:r-r3lr-r r:tlttr)l5((l1{r:}0:.17r ru180i|:lrl0,ir I tr)

29fil2185(j18{81322!tf8;38J;750t6lDi - 1796

- 86t9-120 r-Jjr/-18898-223r tl-27trl-290tr:j-3238 r-3;861-12593-l:911-492fi1-5:rj:lJ;frtjrj-;9?|d-02rll6-0.19:.1,j_[i,(t:.];.)n

209391i012!27 L1033178685&332758140- 2509- 5188tQOrl

-160{}-13321-1n;t-18788-21'?2-2L284-26939-1979;-353,) r-iSrt51-4'-|8r:)li-4358-463t.')li- llhl;.1-;181:J--i J87

-90626844-5838-4890-3985_3119-2289-1487

.)c73S1?r21662847rl416848C9'o44!

60656681i29278938491tl08r-t960rr

I rl!4 t1rl8l311371I l9l:

57102546365351823605u574991648648{71160457'+77743378420340076:193153791816783r300li38r9t:4513 l05r r:970283f626896:155(73 11 1rt2?7tRIt333lfr9 i ilSii:.1


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92 THERMODYNAMICS O F' GASIFiCATION REACTIONSTABLE 24

Free energies of reactions for the dissociation andconversion of methane (cal/moIe)

CH+2H?O =-cor+4H!

THEN,MODYNAMICS OF GASIFICATION REACTIONS 93TABLE 25

Equilibrium constants of reactions for the oxidation ofcarbon by steamT'K lj?o-OH++'/"H,

:98, 16400;0060070080090010101 1001200130014m1500160017001800r900:r100tlnl:l:0023002400150026002700280029003 f00

198772t4t\10062781249230{9

- 2021- 4616- 7236- 9870-15166-7782'+-20485-2314o-25616-2479-33801-3646 t-39126-!4\51-47 Llt'.,-49766-a2431-55080-57750

5524084031!448279562 13301\62478721093- 5699- 12494- 19278- 16059- 32819- 39569- {6290- 53013- i9515- 66302- i3072- 91 t9- 86346- 92966- 997-106169-112736-119303-125860-r 32301

- I 38923

4589033996:8611:306617341 t50558i1394- 6412- 124cJ- 18519- 24588- 30653- 36722- 42786- 48815- 5{706- 60860

- 73038_ 790{- 8;C73- 9108{- 97r)80-10307it-109062-r13017- nl01;- 11098()

362282 t5222173tl /b1336083863296- 1881

- r2t24- 17760- 2311;- 28487_ JJ/D- 39273- 49Eg /- 00c42- 063i7- 1 t76!- 77180- 82593- 88009- 93{16- 98sll-101237- 10963ri-l150J7

298.16450060070080090010001100120013001400150010017001800r90020002f 002200230024250026002700280029003000

9.525 - 10-r77.339.10-rr2.217 . I0-74.813.10-62.288. 10-s4.r83. r0-20.4032.468910.907837.60511.069.1022.616. t}z5 .667. 10s7. tlz. 10t2.Olt:'t}s3.t07.70s5.447.1038.300.10,I .209. 1041 .703. 1042.323.7C^3.085.1043.996.1045. C160. l06.304.10{7.776. t049.296.10I . 105. 105

9.891. 10-121.136.10-73.043. 10-51 -36{ . 10-s2.t54.10-20.17650.925 I3. 534510.736327.354060.528I ,207.1022.781.1023,684.10'5.863.1038.882.102I .289. 1031.804.1032 .435. 10s3.212. 10R4.13L. ty5.201.1086.42. 10,7_804.1039.346. 10'1. 105. 1041.290.1041 .490. 101

1.038. 1051 .548. 1037.372.l}:z28.2749.41264.21972.29721..43160.98430.727 40.56570.459L0.38480.33r30.29120.26070.23660.217 40.20t40. 18860.17780.16860.1608o.15420.14830,14320. 13880. 1349

8 .970 . 10-4r5.723.1.0-30t ,295. 1g-zt2.322. r)-Li2.605 10-10. 136.10-143 .L72.70-128. 668. 10-111..310. 10-01.263.10-88 .632. 10-84.495.1o-11 .884. 10-66 . 606. 10-62.001.10-65.372.10-61 . 300. 10-{2.884.70-4.931. 10-{J.!42.!0-32.rJ79.10-83.605.10-85, 980. 10-8I .548. 10-3'1.472.70-22.202.1.Q-23 .203.10-24 b49. t0-2

3.8 1 0. 10-469. 269. 10-sr1.762.10-201 .300. 10-rr3.99. 10-r81. 672. 10-r7 .848.70-138.022 l0-r21.764. t}-to2.327 . t1-s2.068.1()-8| .347 . t0-76.842.10-72.84fi t0-s9.972.10-63.049. f0-58.294.10-62.042.70-c4. 667. 10-49.665 f0-I .928 . 10-3.531 . 1 0-36.352. 1 0-31.057.10-zI .751.70-22.703.10-:4.201.10-26.094.10-


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Equilibrium constants of reactions for the dissociationand conversion of methane'.( CH.+r"O:-co,+4-ll298.16400500600700800900100011001200

r30014001500160017001800f9002000210022002300:.1.1002500l0rlcl7(0180029000J0


The relation between degree of conversion (x) and theequilibrium constants for various gasification reactionsRooctionI .263 . 10- I3. 179. 10-0

3 . 737. 10-9.991.10-,0.1120.7133.09610.20562.762t.27 1.1022.331. 1023.954.10?6.282 . 10r9.452.101 .302. 1031 .887. tOs2.530 1033.296. 1031r.189. 1035. 221. 1 030,538.10'7. 689. 1019. 1 f9. 1031 .067 . 101I .237 .101{./r18.10{1.611 t0r

1.158.10-301.507. 10-1'6 .037. t0-13I-701.10-82.7 77 . t0-67.071 . 10-30.54317.6003.036.10-r3. 245. 1032.404.7041.328 1055.924. {02.110.1006.537. 107.778. 1011+.34. l0?9.600.10?I .979. 1083. 783. 1086 . BtO. 1081 . 169. 1001.911.10st.95.10e1r.538. l0o0.66 10'9.495.10el-310 l(lto

1 . 203. 10-2?2.333. 10-68.284. l0-rr4.808.10-72.557. 10-{2.983. 10-j1.246782i. 19552 .988. 10-?1.360.1031.3G0 10r6.098 1012 .24r. L0;0.987 . 1051 . C03. 1061+. G39. 1001 .028. 101.1011.107.980 1017. 133. t0?1.2i3.1082,016.1083. 073 . lOsl.0tj. t086. 728. 1089. 51. lr181.318.100I .7811 l0s

1.249. 1(l- !3. 610. 1()-r8I . 137. 10-81.370. l0-2.407 . 11) -30.12592.864736.0?02.941.10'1.7I7 10s7 . 09.i. 1032 .800. 108.622. l0{2.3 15. 105.5lt. 1011.209.105l. i3l. 10"4.i65.1068.027.1001,3{5.10r2.157.10;3.10 1071.01t. tr7.111 tOr9.97i . 10 i1.367.106I .830. 1r)gI 1r')l . l(e

Cf Hro:COfH2c+2HrO:cor_l_:IIrCO+FI1O:CO3+UrC+COr:2COCHn:C-r 2ftzCH4+CO,:2CO+2FI"cH{+H!O:CO+ilt-t1cFI4+2H,O:CO,+4IJ"

3cTa=-.lx2(1-.r)'

4x!

I K, \'1"\t=x,-l{;,l/4+ t

lKo \'/'\1+K,)rKn Y'[a-a ",/4=2-; vK,,

T4,

4x2l-- -;-


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TABLE 28, Equilibrium degree of conversion and gas compositions(per cent by volume) at temperat""*-t.o* zgg. 16 to 1500oKfor gasification reactiorr" "r,d the oxidation of carbon bysteam

. Equilibrium degree of conversion and gas compositions(per cent by volume) at temperatures frm Z9S.i6 to fSOoKof reactions for the conversion of methane

96 THERMoDYNAMICS oF' GASITCATIoN REACTIONS THEN,MODYNAMICS OF GASIF'ICATION REACTIONS 97TABLE 29

cHr-cllHr cH+Ho-co+aH,T"Kc+H,O- CO+Hr

Hro cO+H,o:Co!+Hr I Hio298 .16400500600700800900

1000r 100r200130014001500

0000.0100.0480.2000. s360.8440.9570.9870.9950.9980.999

10010010098.6290.8866.6230.228.482.200.660.240.100.04

0000.691. Jt)

16.6934.8945.7648 9049.6749.8849.9549.98

0000.694.5616.6934.89{. /o48.9049.6849.8849.9549.98

0.997 0. t5

7.90

0. t51,253.957.90

12.3016.3519.85

49.8548.7546.0s42.10/.JU33. 6530. f527.2024.gtJ23.0021.4520.2019. f5

49.8448.754b. u542.1037.7033.6530 1527.2024.9023.0021.4520.2019.ls

298. t40050060070080rl900

100011001200130014001500

000.0100.0500.1650.3890. 6600.8480.9340.9700.980.9910.99

10010098.0990.507 t.7044.0020.418.033.41.2050-720.430.25

001 .919.5028.3056.0079-59

91.9796.5997. 9599.2899.57

0000.00170.0750 2400.5300.8000.9300.9750.9900.9950_997

000.020.070.180.360 .570.730-830.9c0.930.960.97

50505048.742.630.014.55.61.8u.50.20.720.08

50505048.142.630.014,5

1.800.500.20t 4t0.08

0000.9

10.0t7 .524.124.524.924.9tL o

0.0.00.0.00.0.0.0.4

16.19.22_.

9030.

00029

11.130.052.566.7I ,74.574.774.8274.8cJ

0.0.

80.10.00.8030.85

C+CO!-2CO

0000.131.549,4734.0170.8894.o298.1499.2299.83

99.93

c+2HrO-COt+2H, CH+COr:2CO+2Hr cH+2H,o:co,+4HrCo.Hr

298. t640000600?00800900

1000,10012001300r4001500

00-0050.030.120.280.480.650.780.850.900.930.950-96

r0099.294.1.82.562.5L''25.0.16.010,66.9

00.21.96.012.519.225.028.029.831.031.832.232.5

00.53.911.525.038. 550.056.059.662.063.564.465.0

0000-0010.0100.0500.2050.5490.8870.9630.9840.9970.999

99-8798.11690.5365.9929.t25.981.860.780-170.07

2984005006C070080r)9C0

10001100120013001 4001500

0000.010.050.200-520.820.950.980.99

0505049.2t4.1J..115.83

4.D1. 30 .570.160.070.03

50505049.2145.7-r15.834.86r. 360.570. 160.070.07

0000.794.85

16.5734.1745.1448. 6{49.4349.8449.9349.97

H.0000.794,8516.5734.1745-1448,6449.4349.8449.9349.97

. JJ-

29.217 .0t0.33.5

66.766. 765.059.448.434.0ztJ.771.47.0

000.5

9.813.816.517.818.7519.279.419.8

002.o9.19t

39.266.47l.775.076,977.878,6

r""K CH.

1.30.90.6

4.2.61.81.20.


10/20

Conclusions1. Tables have been prepared giving values of theequilibrium constants and ehanges in heat content and freeenergy for ted with the gasification of coal.The tables latest data and perrnit calcula_tions to be rmal and thermodynamie processinvolving t solid fuel.2. Calculation of the degree of conversion and gascomposition at equilibrium enables an estimate to be madeof the depth of the course of gasification reactions and theprobable gas composition, when carrying out a processunder given conditions.

9B THERMODYNAMICS OF GASIFICATION REACTIONS

REI'ERENCES1. D. D. WAGMAN, et aI. ,34,2.143 (1945). J. Res. Nat. Bur. Standards,2. F. D. ROSSINI,2699 (1952). 74, TI,

N.V. LAVROV, The physico-chemical fundamentals offuel combustion and gasifieation (Fiziko-Khimicheskiye osnovy goreniya i gazifikatsiya topliva).Gosenergoizdat, Moscow 00e4.N.V. LAVROV, I.I. CHERNENKOV, V.V. KOROBOV,In: Gasification and combustion of fuels,

CIIAPTER 4EQUILIBRIA IN SYT\]THESIS REACTIONS FROMINDUSTRIAL GASES

1. IntroductionAs correctly stated ln the literature t1l, the discoveryby Kolbet and Engelhardt t 2l of a reaction for.thesynthesis of hydrocarbons and alcohols directly from steamand carbon monoxide, without the need first to obtainexpensive hydrogen, has significantly widened the industrialmanufacture of synthetic liquid fuels and chemical products.A further development in this fierd tBl has been th use ofcheap blast-furnace gas. Studies of synthesis reactionsfrom carbon monoxide and steam, inaugurated at IGI , AN,SSSR t4l , have essentially confirmed ihe results of theGerman workers.The wide scope for the industrial application of this newreaction was the reason which prompted us, in the firstplace, to give a thermodynamic analysis of the process.The present chapter describes the results of our calculations.

().

4.

5.

6.

(Gazifikatsiya i goreniye topliv). Coll. papersAcad. Sci. U. S. S. R. , p. 56 (1gb9).-I. I. CHERNENKOV, In: Gasification and combustion,(Gazifikatsiya i goreniye), CoIl. papers. Acad.Sci.u. s. s. R. (1959).R.R. VENNER, Thermodynamic calculations. IL (1949).N. V. LAVROV, The underground gasification of coal,1, 1o (1958).

2. Selection of Initial Data and Method ofCalculationKolbel and Engelhardt [ 2 ] carried out thermodynamiccalculations with the object of comparing the features of thenew process with those of Fischer-Tropsch. A carefulexamination of their results, however, showed the latter tobe not entirely satisfactory. We are forced to thisconclusion, not only because the calculations were based onout-of-date thermodmamic data, but. mainly because, whencalculating equilibria in reactions involving complexstoichiometric equations, the sign of the change in7-

99


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lOO THERMODYNAMICS OF' GASIFICATION N,EACTIONS

3.

alc ions for alkanes, alkenee andfro

monoxide and hydrogen, and alsobe and eteam, can, in a general way,1) alkanes

Sn{THESIS N,EACTIONS F'N,OM INDUSTRI.A.L GASES 1012) alkenes

3) alcohole2nIl2lnO:CnH*f nHrO3nCO f nHrO : C nH2^ + 2 nCO

nCO+2nHz:C"Hr"arOHf (n - l) HrOSnCO ! (2n | 2) HzO : f H2"+ tOH+ 2 nCO .Calculations were made for three alcohole (ethyl,z -propyl and -butyl) and for alkanes and alkeneecontaini.ng from 2 to 20 carbon atoms all calcurations werecarried out using the equation

- u0R ln.Ko: j-laa ..Results are glven in Tablee 80-84.

TABLE 30r,ogarithms of equilibrium contants for reactions forthe eyntheeie of gaseous alkanes from carbonmonoxide and steam

(2n ! l) H, I nCO : CnH2oa 2f nH2O(3n - 2) CO nH2O:Cn_1H2o-(2n - l) CO2

298.16,t00500600700800900

1000

87.2875.87431.32t17.1607.3720.181- 5.535- r0.080

I l2-38966.57739.5872t ,564

8.712- 0.889- 8.323

r61.37694,63855.3322S,003r 0.387- 3.585_ t{-396

212.713122.U271,t1736,718t2.141

-6.2A4-20.{06-3t-684

2lt,7s7t2l -a7960.0231,2819.566

-8.905-23.t75-3t,,l95

259.7t7r5r.087.03044.32tr3.879- 8.850

-2.437-10-4u

382,69722t,181t .62263.3n18.217

- 15.499-4t.517-62.206

5o5.2e61.935r66.65,r82.33325.s4

- 12.068-56.596-84.007*2, 2, 3, 3- Tetramethylbutane


12/20

IO2 THERMODYNAMICS OF GASIFICATION A,EACTIONSTABLE 31

T.ogarithms of equilibrium constants for the synthesisof gaseous alkanes from carbon monoxide and hydrogen

SYNTT-{ESIS RHA CTIO]VS F'RO]I4 ],NDIISTRJAL GA SES ] O3TABLE 33

Logaritbms of equili.hrium consta-nf s for reacrjons forthe synthesis of gaseous alkenes fr.om carbon monoxirleanr hycr:oqenr"K298.t6,t00500600?00800900t000

29,747t6.35S7. 3000.756

-1. 192-8 0t2-il,7r

96. I6453.1 7221.a,45r0 -224

--lt.?t3- lg.09l-25.0r 0

t!5-280eE.6r834.85412.0{

-4.109- r6.833-26.546

l2{.20366.65532.688

9-00-6,S88- r9.53{-29.3r6

-31,141

299.6:ljt6l.l6078.583

- l7.3rir-4?.70r-71.40o-90.351

c,"H-

l.Eico-5

l.Oclen e298.r6400500600?0080090f)t040

298.r64005 (060070080n900

1000

H

20. rn4t0.6n74.8 9'I 012- r .803

-3.$39-5r6- 6.,q7n

o7 o1o20-230l0 3

3.3n9-t 638- 5."35-- 8 318-t0 6?8

52.5452 554l4 l884,4t-2 571-? 1n5- l2 0?6- lr.42g

53.04528 88614,411

4,12-2-.391-1.735- I .Clt- t5,2,77

53 97t4.9r05.0s9

-2.083-7 -^14- I r.F8

109.89258.R62n.44 I? 85-6.065-ra.l74-?.css-33 sg

5r.60227.95913,8l4.276

-2.925-1.841- t5.207

52.0527.16I r -941t.681-5 7nl-t t.21s-15.626-r9 lon

-to nr, !I

TABLE 32Logarithms of equilibrium constants for reactions forthe synthesis f gaseous alkenes from carbor, *orro*i.and stearn

TARLE 34Logarithms of eouilibrjum constants for the synthesisof gaseorrs alcohols from carhron monoxjcJe anrl hyclrogenanrl from carhon monoxide and steam

ciH^oFt F-C,H,OH n-c,H"oH n-C,H,oH n-c"H,oH98.1610000600?0080090

1000

67.168s9.36822.96712.0r?

4.226-1.63 3-6.r50-9.?43

9r.7r853.12630.861r5.7055.050

- 0.t35-t4-t20

92.67651.07rr6.072

- 2.004-9.r8?

93.r7654,4033r.54t16.283

5.398

-0.097- 14.030

91.0n55.00232.000r6,650

5.?07

-8.798- t3.427

{8s.05627S.960t57.638?6.4tr0r9.005

-83,81!

2J.3220.732 Br,7

-1.810-5.18--7.1 hO-9.?33- 1.334

34.770i8 0537.3330.rn6

-5.105-9.036-12,J04-l 560

4 1.38822,X14lt,4t73.99

-1.293-5.238-r0.7lo

07 06738.8292J.69I 907

l.?3-4,fi5-9.20-t2 99

92.8 r 652-ff5329-040I3.22.fe6

-6.23-t2.736_ rz gsl4 l8 t

*2, 2, 3, 3 -Tetramethylbutane


13/20

104 THERMODYNAMICS O' GASIFICATION REACTIONS SYNTHESIS REACTIONS T'ROM INDUSTRIAL GASES 1053) alcohols (C,FIr"+rOll)4.

1) alkanes (Hr"+r)v - (2n t 1!a+'r' *zn+2. (4n -2 -2nx\2n.p_@;

2) alkenes (C^Hr^)

TABLE 35Equilibrium degree of conversion for reactions for thesynthesis of alkanes from carbon monoxide and steam,and alkane concentrations (per cent by volume) in theequilfbrum mixture

- (2n)2 (x)2"+tl4n-(2n-tr\ x12a-t ."P - -----(ar)3" n"11 {f" -;3) alcohots (CnHzn+rOH)K _ nnx .zn+r . l(4n - l) - 2nxl24'.p-@.

Analogously, for smthesis from CO and H2, we have1) alkanes (CoHro+r)

298. r640050060070080090010000.720.320.090. 01

1212t2L27.42.60.?0.07

0.690.350.100.01

101010t05.50.60.06

0.700.150.01

7.17.17.17.74.00.60.040.07040.01

5.65.65.65.62.90.80.03

! seoclonc

2) atkenes (C"Hrn),, {+rn+ I - 2nx\2a'" (Zn + 1)2+r (1 - sn-r '

,, xntl(\n-2n -l\zn-L\-: '(2n)2 (I-x\sn

298. 16400500600?008009000.620. f90.01

5.65.65.6.5.62,60.0.030.50.220.05

4.J4.54!)4.53.10. 580.1.2

0.610.170.05

J.t

1.40.30.080.60.170.01

2.42,42.4t.030.220.012

12


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106 THFRMOYNAIVIICS OF' GASIFICATION REACTIONSTaking ttre logarithms of theee expressions and substitut_lng valuee of from 0.1 to 0"9, at intervale of 0.1, wearrive at a series of values of lgr(, depenrli.ng ot' .r .-It is then poeeible, by graphical infrpolation, to derivevalues of x dfferent ternperatur"" f"o_ room temoera_ture up to 1000oK.

_ Using theee data, the concentration (per cent by volrrme)of hydrocarbon or alcohol in the equilibrium mixture cp_n teobtained from the formr,rlae,: fr.roo,

where n is the number of gra.m moles of the given compon_ent, Eq is ttre total nurnber of moles in th,e ystem ".r, e,is tbe concentration of the i -th component in the eq.uiribriummixture (per cent by voLume)Results of the calcul.ation of x and g, are given inTatles 35-40.

SYATTHESIS REACTIO\TS FROM INDUSTRLAL GASES 10?rAEL. L 36Equilibriu.m degree of con_version for reactions forthe synthesis of alkenes from carbon monoxide and steam,anrl a-lkene concer:tratj.ons (per cent by voLume) inthe equil jbrir:m mixture

T.Y T rone2-bu?cno298. t6400500600700800900

298.1645006007008009m

14.314.314.314.3128.60.8

11l71lL75.71.9

t.Lt\tlIL5.81.90.3

tl77t7

2.42.42.42.00.980.25

0.740.270.05

0.670.280.06

0.660.270.0s

7770.920.590. J90.03

0.650.270.05.Ei concroK

1t111t1t5.91.9(t.4

7tL0.930.600.190,04

5.95.95.94.20.650. 13

4-74.74.40.52007

7II0.9t0.570,l5


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SYNTHESIS REACTIONS FROM INDUSTRIAL GASES 109TABLE 39

Equilibrium degree of conversion for reactions for thesynthesis of alcohols from carbon monoxide and steam,and alcohol concentrations (per cent by volume) in theequilibrium mixtureTK

Equiribrium degree of conversion for reactions for thesmthesis of alkanes from carbon monoxide and hydrogen,and alkane concentrations (per cent by volume) in theequilibrium mixtureT'K

298. 16400500600700800

7II0.880.480.07

2518.76.80.7

III0.810.23

t4.314.31.4

t7t16.250.72

III0.7 70.1

L117L1

0.

1tL0.690- 08

4.84.84.820.14

7

t0.970.730.300.08

20201972.013.85n ot

14.314.31f .05.00.8

11.1u..1tL .1lt .7/.lJ2.220.43

L

7L0.860.500.10

298 264005006007008009000.700.320.07* 2, 2 " 3, 3-Tetramethylbutane.

TABLE 38 TABLE 40Equilibrium degree of converson for reactions for theEJnthesis of alkenes from carbon monoxide and hydrogen,anci alkene concentrations (per cent by volume) in theequilibriurn rnixture

Equilibrium degree of conversion for reactions for thesrnthesis of normar alcohors from carbon monoxide andhydrogen, and alcohol concentratione (per cent by volume)in the equilibrium mixture

298. 1600500600700800

I10.910.580.190.01

J

28r40.7

Lt0.930.700.240.04

2521tl3.00.4

II0.950.700.21

2020189.82.0

l1LLIL4.80.4-t-


16/20

The resu.l.ts shrw th.at, _for srnthesis from CO and steamat temperatures up to 60OoK, it is possible to achieve yieldsof 1.0-12 per cent by vohrme of the io*", alkanes. Theconcentration of hydrocarbons in the petrol fra,ction(C6-C16) may amount to 4. b-? per cent at these tempera_tures. The:e is an eoual proba.bitity of the formation ofisq-alkanes. Higher alkanes (C1a_b26) can be ohtaineto the extent of 2-3 ner cent.

steam is feasible" sin.ce the yields of hCrocarbons andalcohols deerease sharply with increasL i., t.*p.raturewhen the Fischer-Tropsch process is used.REFERENCES1. Preface to ref. I Z ]

110 THERMODYNAMICS OF GASIFICATION REACTIONSDiscussion of Results

2- H. KOLBEL, F. ENGELHAF.DT,5o 1, 1, (1952). ErdI und Kohle,3. H. KOI.,REL, O. F'RIDEMAN,9,4,208, (1956). 9lg.ol und Kohle,

CHAPTTR 5THE THERMODYNA]I/IICS OF SYNTHESES I'ROMNATIIRAL AND PETA.OI,EIIM GASS

ted more than 50 per cent of th_e vahre of a.ll ehemicalproducts " produeed in the U" S. A. that year.

obtained from petrochemical raw materia.t.s in the U. S. A.in 1955.Such a range of processes and trenrls in synthesisundoutrtedly demanris that attentjon shorrld be pad to thequestion of making th.e fulLest and most economical use ofraw materials. It seems to us that a knowl.edge of thethermodynamic characteristjcs of these processes m-ustlead to a better understand.i.ng of their potenfialities andprobahle that, in many cases, th.ey are not yet being used tothe fullest extent. The present chapter deals u,-r.th theresuLts of calculations reLating to eoui,litrrirrm conditions insJmthesj-s reactions from natrrral and petroleum gases_ $/e

4. I. F. BOGDA.I.ilC)V, et a! In: Gasifcation andSelected va.hres of physical and therm.od.ynarnicproperties of hydroeartons (1g4?).W. B. Person, G. C. pimental, J.Am. Chem. Soc. .75,532, (19s3).Seiectecl values of phvsical and thermodynamicpropertien of hydroeartrons and relatedcompounds ( t 953).

5.6.7.

111


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1I2 THERMODYNAMICS OF' GASIFICATION REACTIONSie, at all temperatures, displaced completely to the right_hand side and its thermodmamics need not be considered.F?:. i full thermodynamic analysis it is necessary, inaddition to the above, to consider the feaeibility ;i a furtherseries of reactions, r/hich may be grouped as follows:1) elimination of hydrogen from methane. Reaction Equilibria in the partial Oxidationoffi

The process of the partial oxidation of methane can berepresented by the following series of reactione:cH. ++o, :*r,r"+f,ruo

*qt. *Lno": *rr,+f,H,ocHn + *o": f,c,un + H,ocH.+*o":cH,o +H,o' cH{**o:co+2H,

cHo * *o,: cHaoHcHn +*o,: *.u", **r,ocH. ++ o,: *qu, + f H,o

CH4 +O,: CH,O + FLO.

SYNTHESES FROM NATUR,AL G.SES 113

,^,: +qH6+ +H, (5. 4)and, further *.,r.: r,n,*in"*.,n. :*"u,*tnu.summarion of these is :::lj,cHo : -1-,1r+ ]ur'The last reaction falling within this group is that for theformation of benzene

o : f cruu * *n,.2') cracking of hydrocarbons to the elemets

(5. 1)(5.2)(5. 3)

AII these reactions are associated with the formation ofvaluable products. Data regarding ttreir equilibria areehown in Table 41.Reaction (5.3) is the sum of (5. 1) and (5.2), but adistinction is made because (5.2) has its own specialinterest. The equilibrium for the reaction for the completeoxidation of methaneCHl + 20, : CO, _l 2HrO 3) reactions between the products formed in accordancewith equations (5.1) and (b.5)

CHn :6.t- 21,*.,n,: c + *u,#",n.: c* Hz*',',:c+*u,*a.".:c+J-H" (5.5)(5.6)


18/20

HHFlH*ld3orol* ur4air#*l*7I .,8 Ei o;+ ;; fr'l-:f-L-Lr :D@^ , , ll ;- a,*f ,5H*h,H*l* 5 I AI i B Il q;f ?i s 5 hFo$ F -f H. s't- B+H orZ

tr Hqn l., 2a)

$E H'q $rf 'xI s6!, '= od 0rl;+ o F?: i'; ! ngii' i il'SY.'f ' ;sFr [ P;aO OY I Hg "i"E T3iil t .s#aE aHs;bi .frE 3ilnsF ts5 oci iri[:D O-P itO { 6'$osq3' EP'*!' e d i3o

TABLE 41Logarithms of equilibrium constants of reactions for the partial oxidationof methane v)zFl{Hv)ldv)qFoEzFltrftov)Hv)1300

1400t500tsHCtl

r .r(cu.+ f o, -- l, c'H'+

+ -l- H"ocr.+*o.:*.,".*tt,o "n.* l-o"- | cn.*{o,=:cH,o+H, I -co+zu, cu,+;o" -. CHOH cH.+{o, -{c.u. +j n,c cH.+*o.:- jc,n, *f n.c cH. + o,:: CH.O + HsO

298 163004005006007008009001000r1001200

14.ffi410.0637.7555.2285. t364.3r53.6863.18{

tt.t778.8517,4936.5945.9545,4765- 1004,8014.5s34-1464.1704,0t83.887

25,181f8.91315.25212.822It,0909. ?958.7861.9827,321.7706.3035.9025.554

t5- 138 r9.57013.92410.6078.3918.8435.6124.6883,950

:

47.38535. 17328.04223.295I 0.91317,37615.405t;r.83012.sJB

1 I .46110.5509.7679.088 10.72t

5t .9532 863


19/20

116 THERMoDYNAMICS oF' GASIT'ICATIoN REACTIoNSTABLE 42

Logarthms of equilibrum constants of reactions forthe elimination of hydrogenI .J(

CH{:1ic.fsI 2H,

."".-'+c2,*I -_z'tt"n, '-) c"url* *",

cH. -- -!-, c,n.++H,

cH:jc"n"+* r' | ^.-T"'t'++; H.2'298.t63004500600700800900t0001t001200130014001500

-6.019-5.985-4.557-3.684-3-088-2.655-.J-2.062-1.849-t .673-1.525-1.398-1. 289-1.195

-8.848-8.775-5.770-6.783_, 1tt-1.839-[.,t71-0.650--4.232o.tt20.397. os0.845t.025

-32.270-32.054-23.284-17.98L-r4.433-1r.888- 9.974- 8.482- 7.287- 6.3{0- 5.494- 4.816- 4.21ts- 3.702

-4.223-4,179-2.393_1 .286-0.5210.187+0.473+0.8141.0941.324!.5171.692I .823t.945

-27.021-18.902-13.741-10.348_ 7.899- 6.046- 4.597- 3.430- 2.473- 1.874- 0.997- 0.4160,086

-12-685-72.579- 8.687- 6.286- 4.652- 3.462- 2.555- 1,839- 1.261- 0.785- 0.386- 0.045o.2470.501TABLE 43Logarithms of equilibrium constants of reactions forthe decomposition of hydrocarbons to the elements

* ".".-:c+1x,2'298. t6300005m60070080090010001t00721300100r5m

-8.899-8..818-5.490-3.427-2.000-0.953-0. f 500.4881.0081,.4351.7932.42.3642,592

-2.881-2.836-0.9420.2551.0871.70t2,17 42.5502.855

3.3193.4993.6523.787

5.9655.9404.8304.2053.8f03.540. 453.2003.085

18.325t8-205r3.270t0-3158.3506.9455.9005.0854.4353.8r03.4703.1002.7802.505

tt.357t t.3129.5648.5767.9527,5267.2r76.9866.8056 -6586.537,rs6-3496.273


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Thermodynamic Textbook 1

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