Formation of carbonyl compounds in lean premixed atmospheric-pressure Ethylene/O2/N2 flames

Abstract

Motivated by a better understanding of lean-fuel combustion, the present study has determined experimentally the chemical structure of four lean ethylene-oxygen-nitrogen flames stabilized on the flat-flame burner at atmospheric pressure (φ = 0.47, 0.508, 0.693 and 0.81). Species mole fraction profiles were also computed by the Premix code (Chemkin II version) and three detailed reaction mechanisms .A very good agreement was observed between the main flame properties: reactants consumption, final products (CO₂, H₂O), main intermediates, and other hydrocarbons in small concentrations, and the modeling. A special care was brought to the examination of the relative importance of carbonyl compounds formation and consumption, mainly (CH₂O and CH₃CHO). Pathway analyses were performed to identify the formation from the direct consumption of ethylene through the C₂H₃ and CH₂HCO. Sensitivity analyses were also performed in order to delineate the most sensitive reaction on the formation and consumption of these two carbonyl compounds.

Keywords: Flame structure, lean flames, ethylene, carbonyl compounds, combustion, mechanisms.