Particle Holdup in a Liquid-Solid Circulating Fluidized Bed

An experiment was conducted to acquire a set of systematic data of particle holdup in risers of a liquid- solid circulating fluidized bed. In the experiment, two kinds of riser were provided, their inner diameter being 24 mm and 36 mm, respectively. Tested particles were of glass and ceramics, having a diameter range from 2.10 to 4.95 mm. Water at ambient conditions was used as the fluidizing liquid. Particle holdup was measured using a shut-off method. Based on the experimental data, a correlation for predicting the particle holdup was derived, which could reproduce almost all experimental data with an accuracy of +/- 15%. The effect of the wall was not recognized within the experimental range, i.e., the diameter ratio of particle to riser is less than 0.2. The independent parameters affecting the flow characteristics of liquid- solid circulating fluidized beds were identified. (C) 2008 Wiley Periodicals, Inc.