Influences of different diluents on ignition delay of syngas at gas turbine conditions: A numerical study

doi:10.1016/j.cjche.2016.06.003

Abstract

Abstract: Ignition delay of syngas is an important factor that affects stable operation of combustor and adding diluents to syngas can reduce NO_x emission. This paper used H₂O, CO₂ and N₂ as diluents and calculated ignition delay of syngas in temperature range of 900-1400 K and at pressures of 10 and 30 atm respectively. In high temperature range, comparing with N₂ dilution, adding H₂O and CO₂ can significantly inhibit autoignition of syngas because they have higher collision efficiencies in reaction H+O₂ (+M)=HO₂ (+M). As for low temperature conditions, adding H₂O can increase reactivity of syngas, especially under high pressure, because of its high collision efficiency in reaction H₂O₂ (+M)=2OH (+M). Comparing with different dilution rates shows that for syngas and operating conditions in this paper, adding N₂ mainly influences temperature rising process of syngas combustion, thus inhibiting reactivity of syngas. In addition, this paper calculated ignition delay of syngas at different equivalence ratios (φ=0.5, 1.0). Higher equivalence ratio (φ≤1) means that less air (especially N₂) needs to be heated, thus promoting ignition of syngas.

Key words: Ignition delay, Reaction mechanism, Combustion, Kinetic modeling, Syngas

摘要： Ignition delay of syngas is an important factor that affects stable operation of combustor and adding diluents to syngas can reduce NO_x emission. This paper used H₂O, CO₂ and N₂ as diluents and calculated ignition delay of syngas in temperature range of 900-1400 K and at pressures of 10 and 30 atm respectively. In high temperature range, comparing with N₂ dilution, adding H₂O and CO₂ can significantly inhibit autoignition of syngas because they have higher collision efficiencies in reaction H+O₂ (+M)=HO₂ (+M). As for low temperature conditions, adding H₂O can increase reactivity of syngas, especially under high pressure, because of its high collision efficiency in reaction H₂O₂ (+M)=2OH (+M). Comparing with different dilution rates shows that for syngas and operating conditions in this paper, adding N₂ mainly influences temperature rising process of syngas combustion, thus inhibiting reactivity of syngas. In addition, this paper calculated ignition delay of syngas at different equivalence ratios (φ=0.5, 1.0). Higher equivalence ratio (φ≤1) means that less air (especially N₂) needs to be heated, thus promoting ignition of syngas.

关键词: Ignition delay, Reaction mechanism, Combustion, Kinetic modeling, Syngas

Dong He, Weiping Yan. Influences of different diluents on ignition delay of syngas at gas turbine conditions: A numerical study[J]. , 2017, 25(1): 79-88.

References

[1] L.D. Thi, Y.J. Zhang, Z.H. Huang, Shock tube study on ignition delay of multicomponent syngas mixtures-Effect of equivalence ratio, Int. J. Hydrog. Energy 39(11) (2014) 6034-6043.
[2] L.D. Thi, Y.J. Zhang, J. Fu, Z.H. Huang, Y. Zhang, Study on ignition delay of multicomponent syngas using shock-tube, Can. J. Chem. Eng. 92(2014) 861-870.
[3] D.M. Kalitan, J.D. Mertens, M.W. Crofton, E.L. Petersen, Ignition and oxidation of lean CO/H₂ fuel blends in air, J. Propuls. Power 23(6) (2007) 1291-1303.
[4] Y.J. Zhang, Z.H. Huang, L.J. Wei, J.X. Zhang, C.K. Law, Experimental and modeling study on ignition delays of lean mixtures of methane, hydrogen, oxygen, and argon at elevated pressures, Combust. Flame 159(3) (2012) 918-931.
[5] Y.J. Zhang, X. Jiang, L.J. Wei, J.X. Zhang, C.L. Tang, Z.H. Huang, Experimental and modeling study on auto-ignition characteristics of methane/hydrogen blends under engine relevant pressure, Int. J. Hydrog. Energy 37(24) (2012) 19168-19176.
[6] A.B. Mansfield, M.S. Wooldridge, High-pressure low-temperature ignition behavior of syngas mixtures, Combust. Flame 161(9) (2014) 2242-2251.
[7] S.M. Walton, X. He, B.T. Zigler, M.S. Wooldridge, An experimental investigation of the ignition properties of hydrogen and carbon monoxide mixtures for syngas turbine applications, Proc. Combust. Inst. 31(2) (2007) 3147-3154.
[8] Z.J. Cao, T. Zhu, Ignition in moderate or intense low-oxygen dilution (MILD) combustion:A numerical study, Chin. J. Chem. Eng. 20(4) (2012) 701-709.
[9] Y.F. Liu, T.F. Wang, Q.X. Li, D.Z. Wang, A study of acetylene production by methane flaming in a partial oxidation reactor, Chin. J. Chem. Eng. 19(3) (2011) 424-433.
[10] G.P. Smith, D.M. Golden, M. Frenklach, et al., GRI-MECH 3.0, 1999 available at http://www.me.berkeley.edu/gri_mech/.
[11] S.G. Davis, A.V. Joshia, H. Wang, F. Egolfopoulosb, An optimized kinetic model of H₂/CO combustion, Proc. Combust. Inst. 30(2005) 1283-1292.
[12] M.V. Petrova, F.A. Williams, A small detailed chemical-kinetic mechanism for hydrocarbon combustion, Combust. Flame 144(3) (2006) 526-544.
[13] A. Kéromnès, W.K. Metcalfe, K.A. Heufer, N. Donohoe, A.K. Das, C.J. Sung, et al., An experimental and detailed chemical kinetic modeling study of hydrogen and syngas mixture oxidation at elevated pressures, Combust. Flame 160(6) (2013) 995-1011.
[14] M. Fischer, X. Jiang, A chemical kinetic modelling study of the combustion of CH₄-CO-H₂-CO₂ fuel mixtures, Combust. Flame 167(2016) 274-293.
[15] M. Fischer, X. Jiang, An investigation of the chemical kinetics of biogas combustion, Fuel 150(2015) 711-720.
[16] M. Fischer, X. Jiang, Numerical optimisation for model evaluation in combustion kinetics, Appl. Energy 156(2015) 793-803.
[17] R. Chacartegui, M. Torres, D. Sánchez, F. Jiménez, A. Muñoz, T. Sánchez, Analysis of main gaseous emissions of heavy duty gas turbines burning several syngas fuels, Fuel Process. Technol. 92(2) (2011) 213-220.
[18] D.E. Giles, S. Som, S.K. Aggarwal, NOx emission characteristics of counterflow syngas diffusion flames with air stream dilution, Fuel 85(12&13) (2006) 1729-1742.
[19] V. Iyer, J. Haynes, P. May, A. Anand, Evaluation of emissions performance of existing combustion technologies for syngas combustion, Proc. ASME Turbo Expo 2(2005) 353-365.
[20] S.Y. Ahn, S.M. Go, K.Y. Lee, T.H. Kim, S.I. Seo, G.M. Choi, et al., The characteristics of NO production mechanism on flue gas recirculation in oxy-firing condition, Appl. Therm. Eng. 31(6&7) (2011) 1163-1171.
[21] K. Cui, B. Liu, Y.X. Wu, H.R. Yang, J.F. Lv, H. Zhang, Numerical simulation of oxy-coal combustion for a swirl burner with EDC model, Chin. J. Chem. Eng. 22(2) (2014) 193-201.
[22] A.K. Das, C.J. Sung, Ignition delay study of moist syngas/oxidizer and hydrogen/oxidizer mixtures using a rapid compression machine, 49th AIAA Aerospace Sciences Meeting, Orlando, US, published by the American Institute of Aeronautics and Astronautics, Inc., Jan 4-7, 2011
[23] O. Mathieu, M.M. Kopp, E.L. Petersen, Shock-tube study of the ignition of multicomponent syngas mixtures with and without ammonia impurities, Proc. Combust. Inst. 34(2) (2013) 3211-3218.
[24] S.S. Vasu, D.F. Davidson, R.K. Hanson, Shock tube study of syngas ignition in rich CO₂ mixtures and determination the rate of H+O₂+CO₂→ HO₂+CO₂, Energy Fuel 25(2011) 990-997.
[25] A.K. Das, C.J. Sung, Y. Zhang, G. Mittal, Ignition delay study of moist hydrogen/oxidizer mixtures using a rapid compression machine, Int. J. Hydrog. Energy 37(8) (2012) 6901-6911.
[26] Chemkin-Pro 15083 Reaction Design.
[27] P. Boivin, C. Jiménez, A.L. Sánche, F.A. Williams, A four-step reduced mechanism for syngas combustion, Combust. Flame 158(6) (2011) 1059-1063.
[28] M. Chaos, F. Dryer, Chemical-kinetic modeling of ignition delay:Considerations in interpreting shock tube data, In. J. Chem. Kinet. 42(3) (2010) 143-150.
[29] M.C. Krejci, M. Olivier, A.J. Vissotski, S. Ravi, T.G. Sikes, E.L. Petersen, et al., Laminar flame speed and ignition delay time data for the kinetic modeling of hydrogen and syngas fuel blends, J. Eng. Gas Turbines Power 135(2013) 1-9.
[30] H.C. Lee, A.A. Mohamad, L.Y. Jiang, Comprehensive comparison of chemical kinetics mechanisms for syngas/biogas mixtures, Energy Fuel 29(2015) 6126-6145.
[31] R. Xiao, M. Zhang, B.S. Jin, Y.J. Huang, H.C. Zhou, High-temperature air/steam-blown gasification of coal in a pressurized spout, Energy Fuel 20(2) (2006) 715-720.
[32] S.R. Turns, An introduction to combustion concepts and applications, second ed. WCB/McGraw-Hill, Boston, 2000622-645.
[33] F.S. Liu, H.S. Guo, G.J. Smallwood, O.L. Gulder, The chemical effects of carbon dioxide as an additive in an ethylene diffusion flame:implications for soot and NO_x formation, Combust. Flame 125(1&2) (2001) 778-787.