Kinetic analysis of the addition of CO2 to the flame in the combustion of methane

The paper presents the results of the calculation of the effect of the CO2 addition in the combustion of methane in air enriched in oxygen up to 25 vol% on the variations in the concentrations of free radicals, CO and NO. The calculations constitute a complement to performed experiments with injecting CO2 at varying distances from the burner. Modelling of the kinetics of methane combustion was done in the Chemked II program by implementing the reaction mechanism GRI-Mech, version 3.0. Residence times of the reagents at temperatures of 1200, 1500 and 1800 K, necessary for obtaining the peak concentrations of H, OH, O and CO, have been determined. It has been demonstrated that the addition of CO2 reduces the peak concentrations of H, OH and O the stronger, the higher the temperature is. If the temperature in the flame region is at a level of 1200 K, then the CO2 addition lengthens the time necessary for achieving the peak reagent concentrations. For T=1100 K, a negligible effect of adding CO2 on the variation in the mole fractions of H, OH, O, CO was noted. The paper enumerates the predominant reactions included in the employed GRI-Mech system, which determine the consumption and production of H, OH, O, CO and NO in the flame.

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Opracowanie ze środków MNiSW w ramach umowy 812/P-DUN/2016 na działalność upowszechniającą naukę.