NO{sub x} formation in lean premixed noncatalytic and catalytically stabilized combustion of propane
- Paul Scherrer Inst., Villigen (Switzerland). Combustion Technology Section
- Univ. Kaiserslautern (Germany)
NO{sub x} formation in combustion of propane/air mixtures is experimentally and numerically investigated. For this, the combustion of preheated (400 C) mixtures with adiabatic flame temperatures from 1,300 to 1,500 C is stabilized by catalytically active and inactive ceramic foam structures in an adiabatic combustion chamber. To study catalytically stabilized combustion, a fraction of the fuel is converted catalytically within the active foam. In noncatalytic combustion, no fuel is converted within the inactive foam. For the modelling, the homogeneous combustion is represented by a one-dimensional, adiabatic, premixed, laminar flame. A detailed chemical mechanism for propane combustion and NO{sub x} formation is included. Experimental and numerical results for NO{sub x} emissions are presented, and the channels of NO{sub x} formation are identified. The calculations show that only little thermal NO{sub x} is formed in the burnt gas by the Zeldovich mechanism because of the low flame temperatures. The NO{sub x} emitted is mainly prompt-NO formed within the combustion zone by the Fenimore, the Zeldovich, and the N{sub 2}O mechanisms. Under the conditions above, the formation of NO reacts most sensitively with respect to the reaction rates of the reactions CH + N{sub 2} = HCN + N and CH O{sub 2} = O + CHO. The NO emissions of the catalytically stabilized flames are remarkably lower than those of the noncatalytic flames and depend on the fraction of catalytically converted fuel. The higher this fraction is, the lower the NO{sub x} emissions are. The calculations indicate that the reduction of prompt-NO formation in catalytically stabilized combustion is due to a decrease in the NO formation via the Fenimore and the N{sub 2}O mechanisms, whereas NO formation via the Zeldovich mechanism is scarcely influenced.
- OSTI ID:
- 93252
- Report Number(s):
- CONF-940711-; TRN: IM9537%%296
- Resource Relation:
- Conference: 25. international symposium on combustion, Irvine, CA (United States), 31 Jul - 5 Aug 1994; Other Information: PBD: 1994; Related Information: Is Part Of Twenty-fifth symposium (international) on combustion; PB: 1838 p.
- Country of Publication:
- United States
- Language:
- English
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