Carbonyl Compounds in Lean Premixed Ethylene/O2/N2 Flames at Atmospheric Pressure

Motivated by a better understanding of lean-fuel combustion, the present study has determined experimentally the chemical structure of three lean ethylene-oxygen-nitrogen flames stabilized on a flat-flame burner at atmospheric pressure (φ = 0.47, 0.70 and 0.81). Species mole fraction profiles have been modelled by the mechanism from the Universite catholique de Louvain (UCL). A very good agreement is observed for the flame properties: the reactants consumption, the final products (CO2, H2O), and the main intermediates. A special care was brought to the examination of the relative importance of carbonyl compounds formation and consumption, mainly the formaldehyde and the acetaldehyde. Using this model, we established that their main formation pathway comes directly from the ethylene consumption through the vinyl radical (C2H3) by reacting with O2 and OH.