Gas and solid discharge from a fluidized bed using a jet pump

Abstract

Solids and gas efflux rates were measured when bed material was discharged from a fluidized bed using a jet pump. The jet pump was located at various heights above the distributor plate and the bed material, sand (mean diameter 262 μm), was fluidized in the range 1 ⩽ U/U mf ⩽ 3. Discharge rates were measured for jet pump flow rates between 0 and 592 cm 3/s. In the passive mode, discharge coefficients were found to be dependent primarily on the fluidizing velocity and to a lesser extent on the bed height. When operating in the active mode, the discharge rates were found to be dependent on the flow rate of the working fluid of the jet pump, the fluidizing velocity and the bed height. Solid loading (wt. of solid discharged/wt. of fluidizing gas discharged) of the ‘induced’ bed material was in the range of 239 to 407. Jet pump efficiency was found to increase with increasing fluidizing velocity, increasing bed depth and decreasing jet pump flow rate. Maximum efficiencies of 20% were achieved. The jet pump was found to be a suitable device for transporting solids from a fluidized bed without significantly affecting bed behaviour.