Effect of CO2 Addition on the Structure of Premixed Fuel-Rich CH4/O2/N2 and C3H8/O2/N2 Flames Stabilized on a Flat Burner at Atmospheric Pressure

Abstract

The effect of replacement of 15% of N2 by CO2 (on a mole basis) in unburnt mixtures on the structure of laminar premixed methane/oxygen/nitrogen and propane/oxygen/nitrogen flames stabilized on a flat burner at 1 atm is studied. The emphasis of this work is on the effect of CO2 addition on the mole fractions of intermediates that are potential precursors of polycyclic aromatic hydrocarbons (PAH). Mole fraction profiles of reactants (CH4, C3H8, O2, and CO2), major intermediates (CH3, CH4, CH2O, C2H2, C2H3, C2H4, C2H6, C3H3, and C3H4) and final products (H2O, CO, CO2, and H2) in fuel-rich (φ = 1.2) CH4/O2/N2, CH4/O2/N2/CO2, C3H8/O2/N2, and C3H8/O2/N2/CO2 flames were measured using flame-sampling molecular beam mass spectrometry and calculated using the PREMIX code and three detailed chemical kinetic mechanisms reported in the literature for combustion of small hydrocarbons: AramcoMech 1.3, Konnov’s mechanism, and GRI-Mech 3.0. Temperature measurements in the flames were carried out using the thermocouple te...