A kinetic study of ethylene oxidation in a well-stirred reactor

Abstract

Experimental results for the oxidation of ethylene in a well-stirred reactor are examined, and the results are analyzed using a numerical model with a detailed chemical kinetic reaction mechanism. Temperatures studied range from 1003 K to 1253 K, at atmospheric pressure and fuel/air equivalence ratio 0.36 to 0.48. The major reactions consuming ethylene are H-atom abstraction by OH radicals and O atoms, and the computed results provide confirmation for the rate determined very recently by Tully for the reaction C2H4+OH=C2H3+H2O k1=2.00×1013exp(−5955/RT), which is lower than rate expressions used previously in the literature by a factor of about 10 over the temperature range studied. Comparisons between computed and experimental results show good agreement at temperatures up to about 1200 K. However, at higher temperatures computed rates of ethylene conversion are much higher than those measured. In the range 1200–1250 K the model predicts effectively complete consumption of the fuel within the given residence time, while the experiments indicate incomplete consumption. These trends, observed previously for n-pentane oxidation in the same well-stirred reactor, are discussed in terms of turbulent mixing and the effects of fluctuations on the rate of fuel consumption in the reactor.