Liquid-phase flow structure and backmixing characteristics of gas-liquid-solid three-phase circulating fluidized bed

A gas-liquid-solid three-phase circulating fluidized bed (GLSCFB) possesses a large application prospect with many advantages. The radial distribution of liquid velocity and liquid phase dispersion characteristics in a GLSCFB of 140 mm i.d. was studied by using the electrolyte tracer method. It was found that liquid velocity distribution was non-uniform in the radial direction. A increase of superficial liquid and/or gas velocity and average solid holdup led to an even radial distribution for the local liquid velocity. Radial distribution of liquid velocity in a GLSCFB is more uniform than that in conventional three-phase fluidized beds. The axial liquid dispersion coefficient is almost independent of the liquid velocity, but tends to increase with the increasing gas velocity and solid holdup. The radial liquid dispersion coefficient increases with the increases of gas velocity and solid holdup, but decreases with the increasing liquid velocity. (C) 1999 Elsevier Science Ltd. All rights reserved.