Effects of gas composition and operating pressure on the heat transfer in an oxy-fuel fluidized bed: A CFD–DEM study

Abstract

CFD-DEM modeling was conducted to study the particle heat transfer in an oxy-fuel fluidized bed under different gas compositions and operating pressures. In particular, to determine the appropriate operating fluidization velocity for the pressurized oxy-fuel fluidized bed, three fluidizing parameters, the excess velocity Uex, fluidization number FN, and Froude particle number Frp, were evaluated by examining the similarities of the flow patterns and the particle heat transfer. The results revealed that the particle heat transfer is positively correlated with the gas density and specific heat capacity, as well as the fluidization velocity. Increasing the operating pressure augments the particle heat transfer, with the rate of increase being the highest at a constant Uex while being less significant at a constant Frp. Moreover, using the constant Frp under pressurized conditions makes possible an almost constant bed expansion and a more desirable particle temperature distribution, as well as a similar thermal input.