The Comparative and Combined Effects of Nitric Oxide and Higher Alkanes in Sensitizing Methane Oxidation

The comparative and combined effects of nitric oxide (NO) and higher alkanes on methane oxidation were examined by experimentation and kinetic modeling. Experiments were conducted using fuel-lean, lower-alkanes mixtures with NO (0–400 ppm v/v) in an atmospheric flow reactor at residence time of 2 s over the temperature range of 820–950 K. NO was found to greatly promote methane conversion, and its sensitizing effect strengthened with the increasing concentration that was added to the system. The promoting effect of higher alkanes on methane conversion was also evident, particularly at zero or low NO concentrations. A strong dependency of the sensitizing effect on the concentration of higher alkanes present was also observed. The kinetic mechanism from Le Cong et al., performed reasonably well in reproducing the experimental trends. However, the sensitizing propensity of higher alkanes in the presence of NO could not be unambiguously ranked under all conditions. Modification to the kinetic mechanism of Le ...