TOMOGRAPHIC AND PARTICLE TRACKING STUDIES IN A LIQUID-SOLID RISER

A liquid-solid circulating fluidized bed is a potential reactor of int erest in a variety of industrial processes, such as petroleum refining , and in the synthesis of fine chemicals, petrochemicals, and foodstuf fs, Rapid deactivation of the solid catalyst in these processes necess itates regeneration and recirculation of the solids into the riser sec tion in which the principal reaction is accomplished In this study we show that computer-automated radioactive particle tracking (CARPT) can be used to obtain solids velocity patterns in the riser and that back flow of solids exists set the tested liquid velocities. gamma-ray comp uted tomography (CT) reveals slightly higher solids concentrations in the center of the column. This is in contrast to gas-solid riser react ors in which the concentration of solids is higher at the walls.