Carbon Monoxide Formation in Oxy-Fuel Combustion

Other conference contribution, 2013

Compared to air-fired flames, an increased in-flame CO concentration has been observed in oxy-fuel combustion. This work analyses the possible explanations for this increase in CO formation. A combustion model is used to investigate the impact of critical combustion parameters on the CO formation routes within a gaseous and lignite fired oxy-fuel flame. In gas-fired oxy-fuel flames the CO formation is promoted by a homogenous reaction between hydrogen radicals and CO2. However, in lignite-fired oxy-fuel combustion, the gaseous reaction route is of less importance to inflame CO formation. Instead CO2 gasification is the largest contributor to the increased CO formation compared to air firing. The substitution of CO2 with steam in the oxidizer during wet oxy-fuel combustion has moderate influence on the CO2 gasification whereas the homogenous CO formation is strongly reduced.