Characterization of Axial and Radial Liquid Mixing in a Liquid−Solid Circulating Fluidized Bed

Abstract

The axial and radial mixing behaviors of the liquid phase in a liquid−solid circulating fluidized bed (LSCFB) were investigated using the electrolyte tracer technique. Tap water and 0.4-mm glass beads with a density of 2500 kg/m3 were used as the liquid and solid phases, respectively. The experimental results showed that the liquid mixing behaviors in the LSCFB were adequately described by the two-dimensional diffusion model. It was found that the axial and radial Peclet numbers of the liquid phase increased with increasing the superficial liquid velocity, whereas they decreased with increasing solid holdup in the column. On the basis of the experimental results, correlations of the axial and radial Peclet numbers under the operating conditions investigated were proposed. The liquid mixing behaviors in LSCFBs and conventional liquid−solid fluidized beds were also compared.