OXIDATION AND IGNITION OF METHANE-PROPANE AND METHANE-ETHANE-PROPANE MIXTURES - EXPERIMENTS AND MODELING

The kinetics of the oxidation of natural gas blends (CH4/C3H8 and CH4/C2H6/C3H8) has. been studied in a jet stirred reactor (900 less than or equal to T/K less than or equal to 1230, 1 less than or equal to P/atm less than or equal to 10, 0.1 less than or equal to equivalence ratio less than or equal to 1.5). Mole fractions of reactants, intermediates and products have been measured in a JSR as a function of temperature and mean residence time. These results have been used to validate a detailed kinetic reaction mechanism. Literature ignition delay times of CH4/C3H8/O-2 mixtures measured in shock tube have also been modeled. A general good agreement between the data and the model is found. The same mechanism has also been used to sucessfully 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 and propane on the oxidation of methane. The computations indicate that the oxidation of methane is initiated by its reaction with O-2 and by thermal dissociation when no other hydrocarbon is present. In CH4/C3H8/O-2 and/or C2H6 mixtures, ethane and propane react first leading to the formation of OH, H and O radicals which initiate methane oxidation.