The effect of NO and SO 2 on the oxidation of a CO-H 2 mixture was studied in a jet-stirred reactor at atmospheric pressure and for various equivalence ratios (0.1, 1, and 2) and initial concentrations of NO and SO 2 (0-5000 ppm). The experiments were performed at fixed residence time and variable temperature ranging from 800 to 1400 K. Additional experiments were conducted in a laminar flow reactor on the effect of SO 2 on CO-H 2 oxidation in the same temperature range for stoichiometric and reducing conditions. It was demonstrated that in fuel-lean conditions, the addition of NO increases the oxidation of the CO-H 2 mixture below 1000 K and has no significant effect at higher temperatures, whereas the addition of SO 2 has a small inhibiting effect. Under stoichiometric and fuel-rich conditions, both NO and SO 2 inhibit the oxidation of the CO-H 2 mixture. The results show that a CO-H 2 mixture has a limited NO reduction potential in the investigated temperature range and rule out a significant conversion of HNO to NH through reactions like HNO + CO ⇔ NH + CO 2 or HNO + H 2 ⇔ NH + H 2 O. The chain terminating effect of SO 2 under stoichiometric and reducing conditions was found to be much more pronounced than previously reported under flow reactor conditions and the present results support a high rate constant for the H + SO 2 + M ⇔ HOSO + M reaction. The reactor experiments were used to validate a comprehensive kinetic reaction mechanism also used to simulate the reduction of NO by natural gas blends and pure C 1 to C 4 hydrocarbons.

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A study of the reduction of nitric oxide (NO) by gas mixtures simulating gases obtained by biomass pyrolysis, in simulated conditions of a reburning zone, has been performed in a fused silica jet-stirred reactor at 1 atm. The temperatures ranged from 1100 to 1400 K, the initial mole fraction of NO was 1000 ppm and that of the reburn-fuel (mixture of CO and H 2 ; mixture of methane, ethylene, and acetylene; and mixture of CO, H 2 , methane, ethylene, and acetylene) was varied. The equivalence ratio was varied from 0.5 to 2.5, corresponding to an excess air of 2 to 0.4. It was shown that the reduction of NO varies as the temperature and that for a given temperature, a maximum reduction of NO occurs, in slightly fuel-rich conditions. Overall, the present results show the same trends as observed in previous studies involving simple hydrocarbons or natural gas as reburn fuel. A detailed chemical kinetic modeling of the present experiments was performed using an updated and improved kinetic scheme. A reasonable agreement between the present data and the modeling was obtained. Furthermore, 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), acetylene, propene, propane, and n-butane. According to this study, NO-reduction (i) by a mixture of CO and H 2 occurs via H) by a mixture of methane, ethylene, and acetylene occurs via HCCO + NO ) HCN + CO 2 and HCNO + CO; HCNO + H ) HCN + OH; HCN + O and OH )> CN, NCO, and NH; CN + O 2 or OH )> NCO; NCO + H )> NH + CO; NH + NO ) N 2 O + H; N 2 O + H ) N 2 + OH; (iii) by a mixture of CO, H 2 , methane, ethylene, and acetylene occurs via (ii).

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The oxidation of HeN has been conducted in a fused silica jet-stirred reactor (1SR) at atmospheric pressure and from \ 000 to 1400 K. The reduction ofnitrie oxide (NO) by HCN has also been studied in a JSR in the same operating conditions. A detailed chemical kinetic model for NO-rebuming (751 reactions and 102 species) was used to simulate the present experiments. An overall good agreement between the experimental results and the modeling was obtained. According to the proposed kinetic mechanism, in the conditions of this study, the oxidation of HeN proceeds mostly through the following sequence: HCN + 0 --? NCO --? NO --? N 20 --? N 2 -The present modeling also shows that the reduction of NO by HeN proceeds according to the following sequence of reactions HeN + 0 --? NCO; NCO + NO --> NzO+ CO and CO 2 + NO; N 2 0 + H --> N 2 + OH.