Kinetic Study on Pyrolysis and Oxidation of CH3Cl in Ar/H2/O2Mixtures

Abstract

Abstract The thermal decomposition of methyl chloride in hydrogen/oxygen mixtures and argon bath gas was carried out at 1 atmosphere pressure in tubular flow reactors. CH3Cl, intermediate, and final products were analyzed over the temperature range 1098 to 1273 K, with average residence times of 0.2 to 2.0 s. A detailed kinetic reaction mechanism based upon fundamental thermochemical and kinetic principles, Transition State Theory and evaluated literature rate constant data was developed to explain and understand the data. The model results show good fits to methyl chloride, intermediate, and final products species profiles with both temperature and time of reaction. The model also fits the data on HCl inhibited oxidation of CO presented in the companion paper by Roesler et al. Reactions showing high sensitivity to inhibition of CO oxidation were identified. The results indicate that the reaction OH + HCl → H2O + Cl is an important source of OH loss. This decrease in OH strongly effects CO burnout. The reactions of CO + HO2 → CO2 + OH and CO + ClO → CO2, + Cl become important pathways for production of CO2 in the fuel rich system when high levels of HCl are present. The termination reaction Cl + HO2 → HCl + O2 is also important to inhibition in the lower temperature regime of this study. We also report on ClO radical reactions with methyl and chloromethyl radicals which form formaldehyde and chloro-formaldehydes that are important to CO formation.