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

The reduction of nitric oxide (NO) by propane in simulated conditions of th e reburning zone has been studied in a fused silica jet-stirred reactor ope rating at 1 arm. The temperatures were in the range from 1150 to 1400 K. In the present experiments, the initial mole fraction of NO was 1000 ppm, tha t 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 temp erature and that for a given temperature, a maximum NO-reduction occurs sli ghtly above stoichiometric conditions. The present results generally follow those obtained in previous studies involving simple hydrocarbons or natura l gas as reburn fuel. The neat oxidation of propane was also studied in the same conditions of temperature, pressure and residence time. A detailed ch emical kinetic modeling of the present experiments was performed using an u pdated and improved kinetic scheme (892 reversible reactions and 113 specie s). An overall reasonable agreement between the present data and the modeli ng was obtained. Also, the proposed kinetic mechanism can be successfully u sed 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-reducti on by propane involves ketenyl radical. The kinetic model indicates that th e reduction of NO proceeds via: C3H8 --> C2H4 --> C2H2 --> HCCO, CH; HCCO NO --> HCNO + CO and HCN + CO2; CH + NO --> HCN; HCNO + H - HCN + OH; HCN + O --> NCO --> NH; NH + H --> N; N + NO --> N-2; NH + NO --> N2O followed by N2O + H --> N-2. (C) 2001 Elsevier Science Ltd. All rights reserved.