High pressure oxidation of C2H4/NO mixtures

Abstract An experimental and kinetic modeling study of the interaction between C 2 H 4 and NO has been performed under flow reactor conditions in the intermediate temperature range (600–900 K), high pressure (60 bar), and for stoichiometries ranging from reducing to oxidizing conditions. The main reaction pathways of the C 2 H 4 /O 2 /NO x conversion, the capacity of C 2 H 4 to remove NO, and the influence of the presence of NO x on the C 2 H 4 oxidation are analyzed. Compared to the C 2 H 4 /O 2 system, the presence of NO x shifts the onset of reaction 75–150 K to lower temperatures. The mechanism of sensitization involves the reaction HOCH 2 CH 2 OO + NO → CH 2 OH + CH 2 O + NO 2 , which pushes a complex system of partial equilibria towards products. This is a confirmation of the findings of Doughty et al. [3] for a similar system at atmospheric pressure. Under reducing conditions and temperatures above 700 K, a significant fraction of the NO x is removed. This removal is partly explained by the reaction C 2 H 3  + NO → HCN + CH 2 O. However, a second removal mechanism is active in the 700–850 K range, which is not captured by the chemical kinetic model. With the present thermochemistry and kinetics, neither formation of nitro-hydrocarbons (CH 3 NO 2 , C 2 H 3 NO 2 , C 2 H 5 NO 2 , CHOCH 2 NO 2 ) nor nitroso-compounds (CH 3 NO, C 2 H 3 NO, C 2 H 5 NO, ONCH 2 CHO, CH 3 C(O)NO, ONCH 2 CH 2 OH) contribute to remove NO x .