Radial and vertical distributions of the interstitial gas velocity in a fluidized bed

Abstract

The radial and vertical distributions of the interstitial gas velocity in a fluidized bed of group B particles were measured over a wide range of superficial gas velocity by applying the optical fiber technique with ozone used as tracer gas. The bed materials were sand particles, dp= 184^m, and alumina beads, rfp = 250pm. The interstitial gas velocities in the jet region were found to be higher than those predicted by the ideal two-phase postulate. This increase reached 30% and 20% of (U0— Umf) for sand particles and alumina beads respectively. These velocities decreased with height above the distributor, approaching those at incipient fluidization near the bed wall but taking still higher values at mid-points. The leakage factor K calculated from the observed interstitial gas velocity was compared to that predicted by a recently developed bubble simulator which was inherently based on the observation of radial and vertical distributions of size and frequency of bubbles, and good agreement was obtained. © 1988, The Society of Chemical Engineers, Japan. All rights reserved.