A PROCEDURE TO DETERMINE PARTICLE AGGLOMERATION IN A FLUIDIZED-BED AND ITS EFFECT ON ENTRAINMENT

Accurate predictions of both the flux and size distribution of the solids entrained above the transport disengaging height of a fluidized bed are necessary. There is no published correlation which accounts for particle agglomeration. No published correlation can accurately predict the flux or size distribution of the particles entrained from a 30-cm i.d. bed of polyethylene particles fluidized at 25 atm. Particle agglomeration greatly affected entrainment. Since the physical processes responsible for agglomeration are too complex for modeling, a reliable procedure was developed to characterize particle agglomeration from entrainment data taken from two completely different series of tests. Several literature models for entrainment were reversed to get the agglomerated fraction of each size cut in the bed solids from the measured size distribution of the entrained particles. A new correlation was developed to calculate size distribution and flux of entrained particles. The agglomeration of the bed particles was modeled with a log-normal probability distribution.