Influence of operating parameters on N2O emission in O2/CO2 combustion with high oxygen concentration in circulating fluidized bed

Oxy-fuel circulating fluidized bed (CFB) combustion combining the advantages of oxy-fuel combustion and CFB technology is one of the most promising technologies for capturing CO2. However, the emission of N2O in oxy-fuel CFB combustion can be high enough to raise some related environmental issues. This study investigated N2O emission in O2/CO2 CFB combustion with a high oxygen concentration based on the experimental results using a the 0.1 MWth oxy-fuel CFB. This study focused on the operating parameters. It was found that increasing the combustion temperature and overall oxygen concentration can lead to lower N2O emission, while increasing the excess oxygen ratio can lead to higher N2O emission levels. Both gas staging and oxygen staging have slight adverse influences on controlling N2O owing to the higher oxygen concentration in the secondary gas. Finally, the excess oxygen ratio in the primary zone was determined in order to assess the actual effects of gas and oxygen staging on both N2O and NO emissions.