NO-reduction by ethane in a JSR at atmospheric pressure: Experimental and kinetic modeling

The reduction of nitric oxide (NO) by ethane in simulated reburning conditi ons has been studied in a fused silica jet-stirred reactor operating at 1 a rm, in the temperature range 900-1400 K, in diluted conditions. In the pres ent experiments, the initial mole fraction of NO was 1000 ppm, that of etha ne was 4400 ppm. The equivalence ratio has been varied from 0.75 to 2. It w as demonstrated that the reduction of NO varies as the temperature and that , for a given temperature, a maximum NO reduction occurs slightly above sto ichiometric conditions. Then, optimal NO-reburning conditions can be achiev ed for particular combinations of equivalence ratio and temperature. The pr esent results generally show the same trends as observed in previous studie s using simple hydrocarbons or natural gas (NG) as reburn fuel. A detailed chemical kinetic modeling of the present experiments was performed using an updated and improved kinetic scheme (877 reversible reactions and 122 spec ies). An overall reasonable agreement between the present data and the mode ling was obtained although improvements of the model are still necessary. T he proposed kinetic mechanism, already successfully used to model the reduc tion of NO by ethylene, acetylene and HCN, and the low temperature interact ions between NO and simple alkanes in a JSR, was also validated through the modeling of the reduction of NO by a NG blend. According to this study, th e main route to NO-reduction by ethane involves ketenyl radical. The model indicates that the reduction of NO proceeds through the reaction paths: HCC O + NO --> HCNO + CO followed by HCNO + H --> HCN + OH; HCN + O --> NCO --> HNCO --> NH2; NHi + NO --> N-2; NH + NO --> N2O; N2O + H O --> N-2.