Computer modeling of cool flames and ignition of acetaldehyde

Abstract

A detailed mechanism for the oxidation of acetaldehyde at temperatures between 500–1000 K has been assembled using 77 elementary reactions involving 32 reactant, product, and intermediate species. Rate coefficients were taken from recent critical evaluations of experimental data. Where experimental measurements were not available, the rate parameters were estimated from the body of currently available kinetics information. The mechanism was shown to predict correctly the rates and products observed in CH 3CHO oxidation studies in a low-pressure static reactor. The same mechanism was used in a model for nonisothermal oxidation of CH 3CHO at low pressure in a stirred flow reactor and at high pressure in a rapid compression machine. The oscilatory phenomena in the flow system and the two-stage ignition observed at high pressure were satisfactorily described by the mechanism. It is shown that cool flames are caused by degenerate branching mainly by peracetic acid and that hydrogen peroxide promotes hot ignition.