Reduction of NO by propane in a JSR at 1 atm: experimental and kinetic modeling

Abstract

The reduction of nitric oxide (NO) by propane in simulated conditions of the reburning zone has been studied in a fused silica jet-stirred reactor operating at 1 atm. The temperatures were in the range from 1150 to 1400 K. In the present experiments, the initial mole fraction of NO was 1000 ppm, that of propane was 2490–2930 ppm. The equivalence ratio has been varied from 0.6 to 2. It was demonstrated that the reduction of NO varies with the temperature and that for a given temperature, a maximum NO-reduction occurs slightly above stoichiometric conditions. The present results generally follow those obtained in previous studies involving simple hydrocarbons or natural gas as reburn fuel. The neat oxidation of propane was also studied in the same conditions of temperature, pressure and residence time. A detailed chemical kinetic modeling of the present experiments was performed using an updated and improved kinetic scheme (892 reversible reactions and 113 species). An overall reasonable agreement between the present data and the modeling was obtained. Also, the proposed kinetic mechanism can be successfully used to model the reduction of NO by ethane, ethylene, a natural gas blend (methane–ethane 10:1). According to this study, the main route to NO-reduction by propane involves ketenyl radical. The kinetic model indicates that the reduction of NO proceeds via: C 3H 8→C 2H 4→C 2H 2→ HCCO, CH; HCCO+NO→ HCNO+CO and HCN+CO 2; CH+NO→HCN; HCNO+H→ HCN+OH; HCN+O→ NCO→ NH; NH+H→N; N+NO→ N 2 ; NH+NO→ N 2 O followed by N 2O+H→ N 2 .