Ethylene oxidation chemistry in a well-stirred reactor

摘要

Ethylene is an important intermediate in the combustion of methane, larger aliphatic hydrocarbons, and aromatics. Detailed fuel-lean C(sub 2)H(sub 4)H(sub 2)O/air well-stirred reactor data by Thornton were used to analyze reported combustion chemistry mechanisms and the development of this study's ethylene oxidation mechanism. The data set had been obtained for the temperature range 1,003 to 1,253 K and ethylene-oxygen equivalence ratio range 0.086 to 0.103, at atmospheric pressure. Mechanisms were derived from reaction sets of Westbrook and Pitz, and Dagaut, Cathonnet and Boettner. Examination of each reported mechanism indicated unusually large kinetic rates for the vinyl decomposition reaction were used in order to obtain agreement with the Thornton data set. An ethylene oxidation model was developed in order to address the mechanistic problems of the previous models. This study's mechanism well simulated the overall rate of ethylene oxidation and concentration profiles of CO, CO(sub 2), H(sub 2), CH(sub 2)O, C(sub 2)H(sub 2), CH(sub 3)OH, CH(sub 4), and C(sub 2)H(sub 6). Successful predictions by the model were dependent on a new high temperature vinyl oxidation reaction route, C(sub 2)H(sub 3) + O(sub 2) = CH(sub 2)CHO + O with a branching ratio of 1.19--1.21 at 1,053 K to 1.63--2.47 at 1,253 K. The branching ratio values were dependent upon the extent of fall-off for the C(sub 2)H(sub 3) + O(sub 2) = CH(sub 2)O + HCO reaction. 132 refs.