Research on the Gas Reburning in a Circulating Fluidized Bed (CFB) System Integrated with Biomass Gasification

N2O emissions from coal fired fluidized-bed combustion are approximately 30–360 mg/Nm, much higher than that from pulverized coal combustion (less than 30 mg/Nm). One approach to reduce the N2O is to reburn the biomass gasification gas in the coal-fired fluidized bed. In this paper, the effects of gasified biomass reburning on the integrated boiler system were investigated by both simulation and experimental methods. The simulation as well as experimental results revealed that the increase of the reburning ratio would decrease the theoretical air volume and boiler efficiency, while it would increase the fuel gas volume, combustion and exhuast gas temperature. The experimental results also indicated that the N2O removal could reach as high as 99% when the heat ratio of biomass gas to coal is 10.5%.