ETHANE OXIDATION AT ELEVATED PRESSURES IN THE INTERMEDIATE TEMPERATURE REGIME - EXPERIMENTS AND MODELING

Ethane oxidation has been experimentally studied in the intermediate t emperature regime under lean conditions using a flow reactor. Species profiles have been obtained for H-2, CO, CO2, CH2O, CH4, C2H4, C2H6, C 2H4O, and CH3CHO at pressures of 3, 6, and 10 atm for temperatures ran ging from 915 to 966 K using a constant equivalence ratio of similar t o 0.2 (in air). To model this data a detailed chemical kinetic model f or ethane oxidation was developed. An optimized reaction mechanism, or iginally developed to model natural gas combustion, was expanded to in clude reactions pertinent to the lower temperature, elevated pressure conditions encountered in the how reactor. The expanded mechanism cons ists of 277 elementary reactions and contains 47 species. By adjusting the rate coefficients of two key reactions the model was brought into agreement with experiment at 6 atm; however, the model indicates a la rger pressure sensitivity than was measured experimentally. Results in dicate that HO2 is of primary importance in the regime studied; contro lling the formation of many of the observed intermediates including th e aldehydes and ethylene oxide. The results also point to the importan ce of continued investigation of the reactions of HO2 with C2H6, C2H5, and C2H4 to further the understanding of ethane oxidation in the inte rmediate temperature regime. The expanded mechanism has also been test ed against shock-tube ignition delay and laminar flame speed data and was found to be in good agreement with both the original GRI-Mech and the experimental data for both methane and ethane.