Nitrous oxide formation and emission in selective non-catalytic reduction process

Abstract

Pulverized coal-fired boilers are not nitrous oxide sources because of high temperature combustion. But selective non-catalytic reduction may produce N₂O by NO reduction reactions. Chemical kinetics calculation and experimental research were used to find out the mechanism between N₂O and N-agent species, N-agent/NO nitrogen stoichiometric ratio (NSR), reaction temperature, reaction time, etc. The results show that N₂O emission decreases with increasing reaction temperature and NSR decreases when reaction time is enough. N₂O concentration first increases then decreases as SNCR reactions keep on occuring. Ammonia SNCR tests indicated that N₂O emission was 0 7 μmol/mol. About 8.7% of NO was transformed to N₂O, and N₂O emission was 27.8 μmol/mol at urea-SNCR test. Urea-SNCR is likely to bring N₂O emission problem.

Keywords

selective non-catalytic reduction, nitrous oxide, nitrogen oxides, ammonia, urea