1. Reducing of kinetic scheme for syngas oxidation at high pressure and elevated temperature Bolshova T.A., Shmakov A.G., Yakimov S.A., Knyazkov D.A., Korobeinichev O.P. Institute of Chemical Kinetics & Combustion, Novosibirsk 630090 Russia 7th International Seminar on Flame Structure, July 11 -15, 2011

2. Introduction SYNGAS, components: H 2 + CO Production technology: –Gasification of fossil fuels (mineral and brown coal) –Processing of natural gas and natural hydrocarbons (catalytic and thermal methods) –Gasification of combustible wastes Spheres of application: –Power engineering –Chemical engineering Problems: –Fire safety –Toxicity –Development of high-tech devices for power chemical engineering (turbines, reactors, etc.)

3. The scheme of power station with the integrated cycle of gasification. Introduction

4. The gas turbine Introduction P 0 - up to 40 atm, T 0 - up to 700 о С

5. Research Objectives Development of the reduced reaction mechanism for syngas oxidation at temperature Т 0 =300-700 K and pressure Р=10-30 bar Validation of the proposed reduced mechanism by comparing the simulated burning rate with experimental literature data

6. Characteristics of Unburnt Gases The fraction of CO in the fuel : а=[CO]/([CO]+[H 2 ])=0.05 0.5 and 0.75 The dilution ratio: D=[O 2 ]/([O 2 ]+[N 2 ])=0.209 (for fuel/air mixtures). Equivalence ratio was : f=([CO]+[H 2 ])/2[O 2 ], where [O 2 ], [N 2 ], [CO] and [H 2 ] - are concentration of oxygen, nitrogen, carbon monoxide and hydrogen respectively.

7. Background Literature experimental data

8. Mechanism for modeling H 2, CO oxidation. Background

9. Model Sun H., Yang S.I., Jomaas G., Law C.K. (Proceedings of the Combustion Institute 31, 2007) H 2 O 2 H 2 O H O OH HO 2 H 2 O 2 CO CO 2 HCO CH 2 O CH 2 OH AR N 2 HE 16 SPECIES and 48 REACTIONS

10. R1 H+O2=O+OHR2 O+H2=H+OH R3 O+H2=H+OHR4 H2+OH=H2O+H R9 H2+H2O=H+H+H2OR13 O+H+M=OH+M R14 H+OH+M=H2O+MR15 H+O2(+M)=HO2(+M) R19 H2+O2=HO2+HR21 HO2+H=OH+OH R22 HO2+O=O2+OHR23 HO2+OH=H2O+O2 R1 H+O2=O+OHR2 O+H2=H+OH R3 O+H2=H+OHR4 H2+OH=H2O+H R5 OH+OH=O+H2OR13 O+H+M=OH+M R14 H+OH+M=H2O+MR15 H+O2(+M)=HO2(+M) R19 H2+O2=HO2+H R21 HO2+H=OH+OH R23 HO2+OH=H2O+O2R24 HO2+OH=H2O+O2 R27 H2O2(+M)=OH+OH(+M)R36 CO+OH=CO2+H R37 CO+OH=CO2+HR38 CO+OH=CO2+H The sensitivity coefficients of burning velocity to the reactions rate constants for H 2 /CO/air flame, р=10, 20, 30 bar CO 5% CO 50% T 0 =300 K f=1 R1 H+O 2 =O+OH R15 H+O 2 (+M)=HO 2 (+M) R36+R37+R38 CO+OH=CO 2 +H

11. The sensitivity coefficients of burning velocity to the reactions rate constants for H 2 /CO/air flame, р= 20 bar  =0.5, T 0 =300 and 700 K,  =0.75 R1 H+O2=O+OH R3 O+H2=H+OH R4 H2+OH=H2O+H R14 H+OH+M=H2O+M R15 H+O2(+M)=HO2(+M) R19 H2+O2=HO2+H R21 HO2+H=OH+OH R36 CO+OH=CO2+H R37 CO+OH=CO2+H R38 CO+OH=CO2+H A rise of initial temperature does not influence on key reactions set

12. The sensitivity coefficients of burning velocity to the reactions rate constants for H 2 /CO/air flame, р= 20 bar  =0.5, T 0 =300 and 700 K,  =3.5 The most appreciable changes of sensitivity coefficients as T 0 rises from 300 to 700 K are observed in the rich flame for reactions R4 (in 8 times) and R15 (in 2 times). R4 H 2 +OH=H 2 O+H R15 H+O 2 (+M)=HO 2 (+M)

13. The sensitivity coefficients of burning velocity to the reactions rate constants for H 2 /CO/air flame, T 0 =300K,  =0.5, р= 20 bar R39 HCO+M=H+CO+M R40 HCO+H=CO+H 2 R1 H+O 2 =O+OH R19 H 2 +O 2 =HO 2 +H R21 HO 2 +H=OH+OH The value of sensitivity coefficient to rate constants of the reactions depends on equivalence ratio .

14. The rate of production of H in H 2 /CO/air flame, T 0 =700K,  =0.5, р= 20 atm.  =0.3  =4.5 R4 H 2 +OH=H 2 O+H R3 H2O+H2=H+OH R37+R38 CO+OH=CO 2 +H R1 H+O 2 =O+OH R15 H+O 2 (+M)=HO 2 (+M) R4 H 2 +OH=H 2 O+H R3 H 2 O+H 2 =H+OH R1 H+O 2 =O+OH R15 H+O 2 (+M)=HO 2 (+M) R21 HO 2 +H=OH+OH

15. The rate of production of CO in H 2 /CO/air flame, T 0 =700K,  =0.5, р= 20 atm.  =0.3  =12 R36+R37+R38 CO+OH=CO 2 +H R39 HCO+M=H+CO+M R35 CO+HO 2 =CO 2 +OH R47 HCO+O 2 =CO+HO 2

16. Н 2 Н+OH H 2 O+H +O +OH 74% 25% CO 2 2 +H +O +OH 94% 5% Н 2 Н+OH H 2 O+H +O +OH 77% 23% CO 2 2 +H +O +OH 85% 6% +H HCO 9% Н 2 Н+OH H 2 O+H +O +OH 83% 17% CO 2 2 +H +O +OH 56% 5% +H HCO 39%  =0.75 =2.0=2.0 =4.0=4.0 The main pathways for H 2 and CO consumption in H 2 /CO/air flame, р= 20 atm, T 0 =300K,  =0.5

17. A reduced reaction mechanism for oxidation of H 2 /CO/O 2 № Reartion A*A*nEa*Ea* S1.H+O 2 =O+OH6.73e+15-0.516670 S2.O+H 2 =H+OH5.06E+42.676290 S3.H 2 +OH=H 2 O+H1.168E+081.523457.4 S4.OH+OH=O+H 2 O3.348e+042.42-1927 S5.H+H+M=H 2 +M7.00E+170.0 S6.H+OH+M=H 2 O+M2.212E+22-2.00.0 S7.H+O 2 (+M)=HO 2 (+M)4.65E+120.440.0 S8.H 2 +O 2 =HO 2 +H7.395E+052.43353502 S9.HO 2 +H=OH+OH6.0E+130.0295 S10.HO 2 +OH=H 2 O+O 2 5E+130.01105.8 S11.CO+O+M=CO 2 +M3.0E+140.03000 S12.CO+OH=CO 2 +H1.8E+51.9-1160 S13.HCO+M=H+CO+M4.0E+130.015540 S14.HCO+H=CO+H 2 1.11E+140.0 * – In: cm 3, mole, s, cal; rate constant expressed as k=A T n exp (-Ea/RT) 13 species (H 2, O 2, H 2 O, H, O, OH, HO 2, CO, CO 2, HCO, Ar, He and N 2 ) and 14 reactions

18. Flame speed of CO/H 2 /Air mixtures as function of equivalence ratio at P=10-30 atm,  =0.05, 0.5, 0.75. Thin lines: model of Sun H. et al., lines with symbols: reduced mechanism Testing of the reduced mechanism

19. Flame speed of CO/H 2 /O 2 /He mixtures as function of equivalence ratio Testing of the reduced mechanism Triangles: experimental data of Sun et al., dashed line: mechanism of Sun et al., circles: reduced mechanism P=20 bar P=10 bar

20. Testing of the reduced mechanism Flame speed of CO/H 2 /O 2 /He mixtures as function of equivalence ratio P=40 bar Triangles: experimental data of Sun et al., circles: reduced mechanism

21. Diamonds and triangles : experimental data of Natarajan et al, circles: reduced mechanism Testing of the reduced mechanism Flame speed of CO/H 2 /O 2 /He mixtures as function as function of  at P=15 atm, T 0 =300K. (  =[CO]/([CO]+[H 2 ])  =0.6  =0.8

22. Lines: mechanism of Sun et al., symbols: reduced mechanism Testing of the reduced mechanism Temperature and concentration profiles in CO/H 2 /Air flame (  =0.5, Р=20 atm, T 0 =300K,  =1)

23. Summary 1.Developed reduced reaction mechanism for syngas oxidation (14 steps, 13 species) satisfactorily predicts burning velocity at P=10-30 atm, T 0 =300- 700K, and  0.05  0.75. 1.Developed reduced reaction mechanism for syngas oxidation (14 steps, 13 species) satisfactorily predicts burning velocity at P=10-30 atm, T 0 =300- 700K, and  = 0.05  0.75. 2.In H 2 / CO mixtures with с  =0.05 the reaction from H 2 oxidation were shown to be key reactions; at  =0.5 and higher the role of reaction CO+OH=CO2+H appreciably increases. 3.Pressure rise from 10 to 30 atm was not shown to influence the set of key reactions. 4.HCO-involving reactions were shown to play a noticeable role in sybgas oxidation only in rich mixtures or at high CO content in syngas.

24. Siemens Ltd. The research was performed under financial support of Siemens Ltd. under agreement #035-СT/2008 Thank you!

26. Flammability concentration limits for CO/H2/Air mixtures as functions of initial temperature (  =0.5, p=1 bar) calculated using mechanism [1] - circles, reduced mechanism (var. #9) - triangles and literature data [Wierzba I., 2005] - squares. Testing of the reduced mechanism

27. O 2 +3H 2 = 2H 2 O+2H(I)* 2H+M  H 2 +M (II)* CO+H 2 O=CO 2 +H 2 (III)* * Wang W., Rogg, B., and Williams F.A. in Reduced Kinetic Mechanism for Application in Combustion Systems (Peters, N., Rogg, B., Eds.), Springer-Verlag, Berlin, p.48, 1993, pp.44-57 Проверка механизма горения сингаза на основе брутто-реакций Зависимость скорости реакций от температуры трех эффективных стадий для пламени СО/H 2 /Air (a=0.5, f=1.0, P=20 atm, T 0 =300K, D=0.209).

28. Аррениусовские параметры констант скоростей реакций для трех эффективных стадий в пламени СО/H2/Air (a=0.5, P=20 atm, T 0 =300K, D=0.209) f IIIIII AE a, cal/molA A Set#1 1 1.0  10 30 56500 9.3  10 13 -21280 2.0  10 14 36560 Set#2 2 1.20  10 26 41830 3.7  10 13 -18900 1.94  10 15 31900 Set#3 3 1.55  10 25 40370 3.22  10 12 -26600 1.87  10 13 34600 Set#4 3.5 1.6  10 25 42723 8.79  10 10 -36500 4.33  10 13 39000 Проверка механизма горения сингаза на основе брутто-реакций Скорость распространения пламени СО/H 2 /Air (a=0.5, P=20 atm, T 0 =300K, D=0.209) от f, рассчитанная с использованием детального механизма реакций Sun H et al, сокращенного механизма и трехстадийного механизма реакций на основе эфективных стадий с различными наборами кинетических параметров констант скоростей

29. Механизм реакций окисления H 2 /CO/O 2 * размерность констант скоростей см 3, моль, сек, кал, К, k = AT n exp(-E a /RT). NoРеакцияA*A*nEa*Ea* 1H + O 2 = O + OH 6.73  10 15 -0.5016670 2O + H 2 = H + OH 3.82  10 12 07948 3O + H 2 = H + OH 8.79  10 14 019170 4H 2 + OH = H 2 O + H2.17E + 081.523457.4 5OH + OH = O + H 2 O3.35E + 042.42-1927 6H 2 + M = H + H + M2.23E + 14096070 7H 2 + H 2 = H + H + H 2 9.03  10 14 096070 8H 2 + N 2 = H + H + N 2 4.58  10 19 -1.4104400 9H 2 + H 2 O = H + H + H 2 O 8.43  10 19 -1.1104400 10O + O + M = O 2 + M 6.16  10 15 -0.50 11O + O + AR = O 2 + AR 1.89  10 13 0-1788 12O + O + HE = O 2 + HE 1.89  10 13 0-1788 13O + H + M = OH + M 4.71  10 18 0 14H + OH + M = H 2 O + M 2.21  10 22 -2.00 1515H + O 2 (+M) = HO 2 (+M) k ∞ 4.65  10 12 0.40 16H + O 2 (+Ar) = HO 2 (+Ar) k ∞ 4.65  10 12 0.40 17H + O 2 (+He) = HO 2 (+He) k ∞ 4.65  10 12 0.40 18H + O 2 (+H 2 O) = HO 2 (+H 2 O) k ∞ 4.65  10 12 0.40 19H 2 + O 2 = HO 2 + H 7.40  10 5 2.4353502 20HO 2 + H = H 2 O + O 1.44  10 12 00 21HO 2 + H = OH + OH 6.00  10 13 0295 22HO 2 + O = O 2 + OH 1.63  10 13 0-445.1 23HO 2 + OH = H 2 O + O 2 l.00  10 13 00 24HO 2 + OH = H 2 O + O 2 5.80  10 13 03974 NoРеакцияA*A*nEa*Ea* 25HO 2 + HO 2 = H 2 O 2 + O 2 4.20  10 14 011982 26HO 2 + HO 2 = H 2 O 2 + O 2 1.30  10 11 0-1629.3 27H 2 O 2 (+M) = OH + OH(+M) k∞ 3.00  10 14 048480 28H 2 O 2 + H = HO 2 + H 2 1.69  10 12 03755.4 29H 2 O 2 + H = H 2 O + OH 1.02  10 13 03576.6 30H 2 O 2 + O = OH + HO 2 8.43  10 11 03970 31H 2 O 2 + OH = HO 2 + H 2 O 1.70  10 18 029410 32H 2 O 2 + OH = HO 2 + H 2 O 2.00  10 12 0427.2 33CO + O(+M) = CO 2 (+M) 3.00  10 14 03000 34CO + O 2 = CO 2 + O 2.53  10 12 047700 35CO + HO 2 = CO 2 + OH 1.15  10 5 2.27817545 36CO + OH = CO 2 + H l.00  10 13 015995.4 37CO + OH = CO 2 + H 9.00  10 11 04570.1 38CO + OH = CO 2 + H 1.01  10 11 059.6 39HCO + M = H + CO + M 4.00  10 13 015540 40HCO + H = CO + H 2 1.11  10 14 00 41HCO + O = CO + OH 3.00  10 13 00 42HCO + O = CO 2 + H 3.00  10 13 00 43HCO + OH = CO + H 2 O 1.02  10 14 00 44HCO + HO 2 = CO 2 + OH + H 3.00  10 13 00 45HCO + HCO = H 2 + CO + CO 3.01  10 12 00 46HCO + HCO = CH 2 O + CO 2.70  10 13 00 47HCO + O 2 = CO + HO 2 5.90E  10 9 0.932737 48HCO + O 2 = CO + HO 2 1.55  10 4 2.38-1526 Sun H., Yang S.I., Jomaas G., Law C.K., High-pressure laminar flame speeds and kinetic modeling of carbon monoxide/hydrogen combustion Proceedings of the Combustion Institute 31 (2007) 439–446