Mild/Oxy-fuel Combustion of a Model Biogas from a Low Temperature Biomass Pyrolysis Process

MILD combustion is very attractive for energy production from diluted gas deriving from bio or thermochemical degradation of biomass. In this work ignition and oxidation of a model gas surrogating the gaseous fraction of biomass pyrolysis products containing C1-C2 species, CO and CO2 was experimentally and numerically studied in presence of large amount of CO2. CO2 significantly alters the ignition in dependence on temperature range. The kinetic model used does not properly reproduces the ignition and oxidation processes in such a no standard condition. Both methyl recombination and CO/CO2 equilibrium cause a delay of ignition in presence of CO2. In low temperature range the CO2 third body efficiency in methyl recombination prevails in the increase of ignition time. The system sensitivity to CO2 increases at high temperature where the CO/CO2 equilibrium is affected by CO2 presence.