SOLIDS CIRCULATION RATE IN SCREEN-BOTTOMED SPOUTED BED WITH DRAFT-TUBE

The solids circulation rate was measured in a spouted bed without a ga s inlet nozzle or orifice, in which the gas was introduced from the sc reen bottom at uniform velocity over the cross section of the vessel, and compared with that in the nozzle or orifice inlet type spouted bed . The rate in the screen-bottomed spouted bed is significantly greater than that in the nozzle or orifice inlet type. It is found that gas f lows from the annulus into the spout through the clearance between the lower end of the draft-tube and the gas inlet screen, and that such a gas flow pattern facilitates the solids circulation in the screen-bot tomed spouted bed. It is a useful for a process in which a high rate o f solids circulation is required.