Frontiers in Energy
Nitrous oxide formation and emission in selective non-catalytic reduction process
State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering of Zhejiang University, Hangzhou 310027, China
Available online: 2007-06-05
Pulverized coal-fired boilers are not nitrous oxide sources because of high temperature combustion. But selective non-catalytic reduction may produce NO by NO reduction reactions. Chemical kinetics calculation and experimental research were used to find out the mechanism between NO and N-agent species, N-agent/NO nitrogen stoichiometric ratio (NSR), reaction temperature, reaction time, etc. The results show that NO emission decreases with increasing reaction temperature and NSR decreases when reaction time is enough. NO concentration first increases then decreases as SNCR reactions keep on occuring. Ammonia SNCR tests indicated that NO emission was 0 7 μmol/mol. About 8.7% of NO was transformed to NO, and NO emission was 27.8 μmol/mol at urea-SNCR test. Urea-SNCR is likely to bring NO emission problem.