1998 Volume 41 Issue 4 Pages 959-965
The effect of initial CO2 concentraion on NO destruction and regeneration was investigated as part of our ongoing research on NO emission from CO2 recycled coal combustion, which could realize easy CO2 recovery and drastic NO reduction simultaneously. Experiments were carried out in a flat flame burner for CH4 / O2 / Ar / NO / CO2 flame at various excess oxygen ratios(from 0.6 to 1.2) and CO2 concentrations(from 0% to 48%). It was found that CO2 has a pronounced negative effect on the destruction of NO under fuel-rich condition. In contrast, under fuel-lean condition, the effect of CO2 becomes smaller even at high CO2 concentration. Kinetic Modeling showed that a large part of NO is regenerated through the reaction N+CO2=NO+CO at high CO2 concentrations. The effect of CO2 is not so significant under fuel-lean condition because this reaction is no longer competitive with other NO formation reactions in this case.