New measurements on hydrodynamics in a gas–liquid–solid expanded bed

Abstract

The solid holdup, in a 150mm-ID×2460mm-height gas–liquid–solid expanded bed with air, water and glass beads (the diameter of particles is 0.6–0.8mm) was firstly investigated based on the immersion-type online multiphase measuring instrument, and bubble behavior was studied via the BVW-2 double electrical conductivity probe. The effect of the superficial gas velocity and liquid velocity on the expanded ratio, the transition ratio, the bubble rising velocity, the gas holdup and the solid holdup was studied. It is discovered that compared with the gas velocity, the liquid velocity has stronger impact on the expanded ratio, but it is opposite for the transition ratio. The average gas holdup and solid holdup increase linearly as the superficial gas velocity goes up. Among it, the gas holdup increases greater in the center, while the solid holdup increases greater near the wall. Compared with it, when the superficial liquid velocity rises, the average gas holdup hardly changes, but the average solid holdup keeps decreasing, especially the solid holdup distributes flatter with the increase of the superficial liquid velocity.