Chemical structures and theoretical models of lean premixed atmospheric-pressure propene/O₂/N₂ flames

Abstract

To better understand the chemistry involved in the lean-fuel combustion, the chemical structure of lean premixed propene-oxygen-nitrogen flames stabilized on a flat-flame burner at atmospheric pressure was determined experimentally. The species mole fraction profiles were also computed by the Premix code and three detailed reaction mechanisms. A very good agreement was observed for the main properties: reactants consumption, final products (CO₂, H₂O) and the main intermediates: CO and H₂. Only a general agreement is also observed between predicted and measured mole fraction profiles for minor intermediates. Marked differences occurred in the prediction of active intermediate species present in small concentrations. Pathways analyses were performed to identify the origins of these discrepancies. It was shown that the same reactions were involved in the three mechanisms to describe the consumption of propene, but with marked differences in their importance. C₂H₅, C₂H₄, and C₃H₅ are the main species formed in the first step and their consumption increases the differences between the mechanisms either by the use of different kinetics data for common reactions or by differences in the nature of the consumption reactions.

KEY WORDS: Flame structure, Lean flame, Propene, Combustion mechanisms

Bull. Chem. Soc. Ethiop. 2012, 26(2), 211-226.

DOI: http://dx.doi.org/10.4314/bcse.v26i2.5