Development of High-Flux Solid Circulation Systems with Riser, Downer and Bubbling Fluidized Bed

Abstract

A circulating fluidized bed coal gasifier cold model, which consists of an acrylic riser (0.05m-i.d.×6m-high), a downer (0.1m-i.d.×1.3m-high), a bubbling fluidized bed (0.37m×0.08m×1.5m), was set up. Solid mass flux (G_S) of silica sand particles (density=2600kg/m^3 and average particle size=83μm) and solid separation efficiency of a separator installed at the bottom of the downer were measured. The maximum obtained G_S was 238kg/(m^2・s) when the riser gas velocity (U_<gr>) was 8m/s and solid inventory (I_s) was 50.9kg. It is found that the solid mass flux was obviously affected by the solid inventory and the riser gas velocity. The solid separation efficiency was 98.2-99.6% when the downer gas velocity was 1-3m/s.