NO2-promoted oxidation of methane to formaldehyde at very short residence time – Part II: Kinetic modeling

Abstract

Partial oxidation of methane in the presence of NO2 at short residence time (20–80ms) provides a promising route to yield formaldehyde. In this paper, an approach for modeling the kinetics of the complex reaction system CH4/O2/NO2 is presented. A detailed kinetic model is proposed, which is based on the previous mechanism of Zalc et al. (2006) [34] in which some changes were made, including the correction of several rate constants, the addition of two reactions involving HONO and the updating of the thermodynamic data for CH3NO2 and HONO. The final kinetic model is compared with our experimental results in terms of CH4 conversion as well as product concentrations. The simulation results are in good agreement with the experiments for various temperatures, residence times, XO2/XCH4 ratios and initial NO2 concentrations. The proposed kinetic model is also tested against the previously published experimental data for the oxidation of methane in the presence of NOx (x=1 or 2). The overall good agreement further confirms the reliability of the kinetic model.