Simultaneous solids entrainment and de-entrainment above a three-phase fluidized bed.

Abstract

Particle entrainment in the freeboard region above a cocurrent gas-liquid fluidized bed arises largely as a result of the solids carried in the wakes of the gas bubbles leaving the bed. It is by the periodic wake-shedding which takes place in the freeboard that de-entrainment gradually occurs. This freeboard phenomenon was modelled as a stagewise partition process. The predictions of the model were compared with solids entrainment as obtained from measured axial pressure profiles in the freeboard of air-water fluidized beds of glass beads, for three bead sizes and different air and water velocities. Agreement with the experimental data was good. (from author's abstracts)