Effects of NH3 on N2O formation and destruction in fluidized bed coal combustion

Abstract

The NH3 oxidation and reduction process are experimentally and kinetically studied in this paper. It is found that NH3 has contributions not only to N2O formation, but also to N2O destruction in certain conditions. The main product of homogeneous NH3 oxidation is found to be NO rather than N2O, but some bed materials and sulphur sorbents have catalytic contributions to N2O formation from NH3 oxidation. In reduction atmosphere, NH3 can promote the KC destruction. It is deduced that the ammonia injection into fluidized bed coal combustion flue gas can decrease both NOx and N2O emissions. The ammonia injection process is kinetically simulated in this study, and the reduction rates of NOx and N2O are found to depend on temperature, O2 concentration, initial NOx and N2O concentrations, and amount of injected ammonia.