COMPUTATIONAL FLUID DYNAMICS MODELING OF BIOMASS CO-FIRING IN A 300 MW PULVERIZED COAL FURNACE

Abstract

Biomass energy is one of the most accessible and readily available carbon-neutral energy options as a RES. It is regarded as a viable alternative fuel for coal com-bustion, particularly for biomass co-firing with pulverized coal, with numerous applications. The CFD can provide reasonably accurate solutions to complex thermo-chemical-fluid interactions, which is useful for understanding the design or retrofit of boilers and can save time, money, and effort. In this study, a CFD simulation of a 300 MW pulverized coal boiler with biomass co-firing was per-formed to investigate the impact of biomass co-firing with coal, considering the biomass co-firing ratio, mixing effect, and feeding temperature. The results show that the flow field in the furnace does not change significantly under different bio-mass blending ratio. Biomass co-firing can reduce peak temperatures in the fur-nace and make the temperature distribution more uniform. The concentration of unburned carbon in the furnace decreases as the biomass blending ratio increases. Furthermore, biomass blending has a significant impact on nitrogen oxide reduc-tion, with NOx emissions reduced by 20% and 28%, respectively, when the biomass blending ratio is 15% and 30%. The change of parameters inside the furnace caused by the reduction of biomass powder feeding temperature about 80 K is not significant. On the other hand, co-firing biomass with coal, reduces the risk of bi-omass spontaneous combustion while maintaining the furnace combustion stability and boiler combustion efficiency. The optimum ratio of biomass co-firing ration is deduced in this study is up to 20%.