Numerical and Experimental Study on Oxy-fuel Coal and Biomass Co-firing in a Bubbling Fluidized Bed

Abstract

As one of the most promising approaches to reduce CO2 emissions from power plants, oxy-fuel fluidized bed combustion technology still has a lot of basic uncertainties requiring in-depth studies, especially in application for coal and biomass co-firing. This work focuses on results of coal co-firing with biomass under O2/CO2 combustion conditions in a 6 kWth bubbling fluidized bed combustor. With the same thermal input maintained, computational fluid dynamics (CFD) was adopted as a predictive tool to examine the effects of firing coal and co-firing biomass with coal under O2/CO2 atmospheres. Hydrodynamics, heat transfer, species concentration, and char gasification in a fluidized bed were investigated. In comparison to coal combustion, the hydrodynamic and temperature profiles of biomass co-firing are not affected much when maintaining the same thermal input. The temperature of biomass co-firing at the bottom of the dense-phase zone, which is mainly the char combustion area, is about 10 K lower than that o...