Experimental Investigation and Computer Simulation of Products During the Induction Phase of Methane Oxidation from 1170 to 1460 K

Abstract

– A molecular beam source reactor is used to study the oxidation of methane at temperatures from 1170 to 1460 K, pressures above 1000 mbar and residence times of about 3 msec. The mixtures investigated range from lean to rich conditions. The products detected in the induction phase or the reaction up to the ignition point arc H₂O, H₂, CH₂O, C₂H₆, CO, C₂H₄. CO₂, C₂H₂ and C₂H₂O. A recent flame chemistry reaction model is extended by elementary reactions important for the induction phase and used to simulate the experimental data. The general agreement is good, although quantitative discrepancics remain. Analysis of the major reaction pathways shows that the reactions of the methyl radical in the induction phase up to high conversions are distinctly different from the ones in flames: CH₃ is mostly oxidized by the HO² radical, with minor contributions from the reactions with O₂ and O.