HYDRODYNAMIC CHARACTERISTICS OF A 3-PHASE INVERSE FLUIDIZED-BED COLUMN

Gas- liquid- solid inverse fluidized bed were studied in which the gas and the continuous liquid phase flow countercurrently fluidizing part icles that are lighter than the liquid. Conductivity and static pressu re measurements were combined to provide the vertical profiles of the gas liquid and solid holdup, in beds of 4- or 6-mm polypropylene parti cles with a density of about 870 kg/m(3). Various bed heights were obt ained with different measurement methods. The minimum fluidization vel ocity was estimated using the bed static pressure gradient. A new tran sition velocity, called the uniform fluidization velocity, was identif ied using conductivity measurements. This is the superficial liquid ve locity at which the fluidization quality becomes the same throughout t he bed.