Experimental and kinetic study of NO-reburning by syngas under high CO2 concentration in a jet stirred reactor

Abstract The NO-reburning by syngas is investigated by the jet-stirred reactor (JSR) experiments and kinetic modeling. The effects of CO2 and methane are studied systematically under different reaction temperatures (T), equivalence ratios (Φ) and initial ratios of hydrogen to carbon monoxide (α). The kinetic modeling is carried out by the present modified detailed mechanism consisting of 151 species and 1408 reactions. The modeling results obtained using the present modified mechanism demonstrate the good consistency with experiments under most of the conditions. The CO2 has significant inhibitory effect on the NO-reburning by syngas independent of variations in T, Φ and α. The maximum NO reduction efficiency is remarkably reduced than that under N2 condition by at least 76%. The addition of 1000 ppm methane has been found to increase the NO-reburning by the syngas for CO2 conditions by at least 243%. The effects of CO2 and CH4 must be considered for NO-reburning by syngas as the actual syngas contains CO2 and methane. Considering the presence of CO2 and CH4, the optimal condition to maximize the NO reduction efficiency is T ≈ 1150 K, Φ ≈ 1.67 and α ≈ 1. The mechanism under this optimal condition is determinate by pathway and sensitivity analyses. The critical reactions for NO-reburning by syngas in the presence of CO2 and CH4 are identified, which are important for future mechanism development and application of NO-reburning by syngas.