Chemical kinetic modeling of ethene oxidation at low and intermediate temperatures

Abstract

A detailed chemical kinetic mechanism for ethene oxidation has been developed and used to model low to intermediate temperature oxidation chemistry. The model was used to simulate the reactions in a static reactor at temperatures of 696 K and 718 K, an equivalence ratio of 2.0, and a pressure of 600 torr. The modeling calculations identified some of the key reaction steps at these conditions. The formation of the majority of the reaction intermediates results from two main paths involving the reaction of ethene with HO 2 and OH. The addition of HO 2 to ethene leads to ethene oxide, which becomes a source of methyl radicals. The methyl radicals lead to the formation of methane and methanol. The addition of OH to ethene leads to formaldehyde, which is subsequently converted to CO and CO 2 . Formaldehyde also results from the OH abstraction path via the vinyl radical. At temperatures near 700 K, OH abstraction is less important than OH addition. However, the relative importance of the abstraction path increases with temperature. Modeling results at these conditions were compared with experimental species concentration data. The calculated concentrations of the major products ethene oxide and carbon monoxide are in very good agreement with the experimental data. The calculated concentrations of formaldehyde and methanol are low. The calculated methane concentrations are in good agreement in the early stages of the reaction, but are overpredicted in the latter stages. The similarities and differences in agreement between the modeling and experimental results are discussed.