An experimental and kinetic study of propanal oxidation

Propanal is a critical stable intermediate derived from the oxidation of 1-propanol, a promising alcohol fuel additive. To deepen the knowledge and accurately describe propanal combustion characteristics, new burning velocity measurements at different temperatures were carried out and a new detailed kinetic mechanism for propanal was proposed. Experiments were performed using the heat flux method and compared with literature data. Important discrepancies were noted between the new and available data, and possible reasons were suggested. Flow rate sensitivity analysis highlighted that, as expected, the important reactions influencing the propanal oxidation in flames are pertinent to H2 and CO sub-mechanism. Current mechanism is based on the most recent Konnov model, extended to include propanal chemistry subset. Rate constant parameters were selected based on careful evaluation of experimental and theoretical data available in literature. Model validation included assessment against a large set of combustion experiments obtained at different regimes, i.e. flames, shock tubes, and well stirred reactor, as well as comparison with the semi-detailed (lumped) kinetic mechanism for hydrocarbon and oxygenated fuels from Politecnico di Milano, detailed kinetic model from Veloo et al. and low temperature oxidation of aldehydes kinetic model of Pelucchi et al. The proposed model reproduced experimental burning velocities, ignition delay times, flame structure and JSR data with an overall good fidelity, while it reproduces only qualitatively the species distribution of propanal pyrolysis.