Effect of the Chemical Structure of Hydrocarbons on the Emissions of CO, CO2 and Soot Precursors Issued from Cyclohexane and Benzene Premixed Flames

A kinetic modeling comparative study of the combustion of two cyclic hydrocarbons having the same number of carbon atoms and a different chemical structure (cyclohexane and benzene) was carried out using the PREMIX calculation code developed around the CHEMKIN II formalism, under the conditions of three equivalence ratios (phi = 0.8, 1 and 1.8) of CYC6H12/air and C6H6/air premixed laminar flames, using two previously validated and published models. It has been found that aromatization played a primordial role in the formation/depletion reactions of pollutants. The modeling results indicated that the combustion of benzene produced high concentrations of CO, CO2, C2H2, C3H3 and C5H5 as compared to cyclohexane. In addition, one of the main objectives of this study was to obtain a good understanding of the effect of fuel structure on CO, CO2 production(,) as well as on the formation mechanisms of soot precursors. This goal was achieved by analysing the reaction pathways, which allowed us to propose detailed kinetic schemes explaining the formation or depletion paths of each pollutant issued from the two investigated fuels.