Hydrodynamic of a Novel Liquid-Solid Circulating Fluidized Bed Operating Below Particle Terminal Velocity
Abstract
A novel type of circulating fluidized bed operating below the particle terminal velocity known as conventional circulating fluidized bed (CCFB) was proposed and tested for the first time in this study. The experiments were carried out in a liquid-solid circulating fluidized bed system, where both liquid and solid flew upwards in the riser and solids exiting the top of the riser were separated from liquid and then returned to the bottom of the riser via an accompanying downer. The system was essentially operated in the conventional fluidization regime but with continuously feeding of particles into riser bottom and particles moving up the riser to achieve solids circulation or circulating fluidization. The hydrodynamic of the CCFB was investigated at various operating conditions with two types of particles. The solids holdup of the conventional circulating fluidization was clearly higher when compared to conventional fluidization. Particles with a higher terminal velocity have higher solids holdup.