Pyrolysis, oxidation and ignition of C1 and C2 hydrocarbons: experiments and modeling

Abstract

The kinetics of the oxidation of natural gas blends (CH4/C2H6) and of ethylene and ethane has been studied in a jet stirred reactor (850 ≤ T/K ≤ 1240, 1 ≤ P/atm ≤ 10, 0.02 ≤ equivalence ratio ≤ 2.0) for the first time. The concentration profiles of reactants, intermediates and products measured in a JSR have been used to validate a detailed kinetic reaction mechanism. Literature ignition delay times of CH4/C2H6 mixtures measured in shock tube have also been modeled as well as shock tube pyrolysis of ethylene. A general good agreement between the data and the model is found. The same mechanism has also been used to successfully represent the oxidation of methane, ethyne, ethene, ethane, propene, and propane in various conditions including JSR, shock tube and flame. The present study clearly shows the importance of traces of ethane on the oxidation of methane. The computations indicate that the oxidation of methane is initiated by its reaction with O2 and by thermal dissociation when no other hydrocarbon is present. However, in the studied CH4/C2H6 mixtures, ethane reacts before methane leading to the formation of OH, H and O radicals which initiate methane oxidation. The major importance of ethyl radical reactions is demonstrated by the computations.