Hydrodynamic Behaviors of a Large-Scale Triple-Bed Circulating Fluidized System with High Solids Fluxes

The objective of this study is to investigate the flow behaviors of a circulating fluidized bed (CFB) with high solid mass flux and large solid holdup, which could circulate inert particles to supply the heat for coal/biomass gasification reaction. A large scale CFB cold model, which is composed of a 0.1m(i.d.)X15.7m riser, a multi-tube solids distributor, a 0.1m(i.d.)X6.0m downer, a gas-solids separator, a 0.75m X 0.27m X 3.4m bubble fluidized bed, and a 0.15m(i.d.) X 5.0m moving bed, is set up. Flow behaviors were investigated and discussed using silica sand as bed materials with different solid inventories. The pressure distributions along the circulating system were obtained. The solids hold-ups in the riser and downer were measured by electrical capacitance tomography, and the obtained results were analyzed and discussed.