ETHYLENE OXIDATION IN A WELL-STIRRED REACTOR

The detailed ethylene oxidation data set of Thornton [1], obtained for a well-stirred reactor operated fuel-lean at atmospheric pressure and for temperatures of 1003 K to 1253 K, is used as a basis for the comparison of chemical kinetic mechanisms reported in the literature and for the development of a new ethylene oxidation mechanism. The mechanisms examined are those of Westbrook and Pitz [2] and Dagaut et al. [3]. These mechanisms indicated that unusually large rates for the vinyl decomposition reaction are required to obtain agreement with the Thornton data set. A new ethylene oxidation mechanism is developed in order to overcome some of the drawbacks of the previous mechanisms. The new mechanism closely simulates the overall rate of loss of ethylene, and the concentration of CO, CO2, H-2, CH2O, C2H2, CH3OH, CH4, and C2H6 measured for the stirred reactor. Predictions by this mechanism are dependent on a new high temperature vinyl oxidation route, C2H3 + O-2 = CH2CHO + O with a k(C2H3+O2=CH2CHO+C)/k(C2H3+O2=CH2O+HCO) branching ratio of 1.4 at 1053 K to 2.05 at 1253 K. The branching ratio values were dependent upon the extent of fall-off for the C2H3 + O-2 = CH2O + HCO reaction. (C) 1995 John Wiley & Sons, Inc.