NO and N2O Emissions during Devolatilization and Char Combustion of a Single Biomass Particle under Oxy-fuel Conditions at Fluidized Bed Temperature

Abstract

Oxy-fuel fluidized bed combustion is a novel clean-biomass utilization technology. The NO and N2O emissions during oxy-fuel combustion of a single biomass particle at fluidized bed temperature were studied in a flow tube reactor. The method of isothermal thermogravimetric analysis was used to distinguish the devolatilization and char combustion stages of biomass combustion. This work is aimed to study the effects of temperature, CO2 concentration, atmosphere and O2 concentration, H2O vapor addition, and biomass type on the NO and N2O emissions during oxy-fuel combustion of a single biomass particle at fluidized bed temperature. In oxy-fuel combustion, NO is rapidly formed during the devolatilization stage, while N2O is mainly formed during the char combustion stage. In 30% O2/70% CO2 at T = 800 °C, the conversions of fuel-N to NO and N2O are 11.96% and 18.98%, respectively. The conversion of fuel-N to NO reaches the maximum value at T = 800 °C during the devolatilization stage, while it increases with inc...