Acetaldehyde oxidation at elevated pressure

A detailed chemical kinetic model for oxidation of CH 3 CHO at intermediate to high temperature and elevated pressure has been developed and evaluated by comparing predictions to novel high-pressure flow reactor experiments as well as shock tube ignition delay measurements and jet-stirred reactor data from literature. The flow reactor experiments were conducted with a slightly lean CH 3 CHO/O 2 mixture highly diluted in N 2 at 600–900 K and pressures of 25 and 100 bar. At the highest pressure, the oxidation of CH 3 CHO was in the NTC regime, controlled to a large extent by the thermal stability and reactions of peroxide species such as HO 2 , CH 3 OO, and CH 3 C(O)OO. Model predictions were generally in good agreement with the experimental data, even though the predicted temperature for onset of reaction was overpredicted at 100 bar. This discrepancy was attributed mainly to uncertainties in the CH 3 C(O)OO reaction subset. Predictions of ignition delays in shock tubes and species profiles in JSR experiments were also satisfactory. At temperatures above the NTC regime, acetaldehyde ignition and oxidation is affected mainly by the competition between dissociation of CH 3 CHO and reaction with the radical pool, and by reactions in the methane subset.