Axial holdup distributions of gas and solid particles in three-phase fluidized bed for gas-liquid(slurry)-solid systems.

Abstract

The behavior of gas and solid particles was studied in a so-called three-phase fluidized bed of 12-cm diameter. The mean gas holdups in the dense and lean regions and the mean solid holdup in the dense region were correlated by experimental equations. The axial distribution of solid holdup in the lean region was analyzed by the sedimentation diffusion model. The mean settling velocity, vp9 and the longitudinal dispersion coefficient of solid particles, Ep9 were correlated with previous data for bubble columns with suspended solid particles, respectively, as follows. Z)r/£p = {13Fr/(l + 8Fr°-85)}(l + 0.023Fr -°-8) where DT = column diameter; dp -particle diameter; Fr-Ug/^JgDT; g -acceleration of gravity; Ug = superficial gas velocity; vt = terminal velocity of solid particle; vl -kinematic viscosity of liquid or slurry; \j/l = (volume fraction of liquid or slurry)/(l-volume fraction of gas).

Ultrasonic technique to determine particle size and concentration in slurry systems

“…8). However, literature review shows that the concentration in GLS systems varies with axial height and is dependent on the gas velocity, particle size and their concentration (Smith et al, 1986;Smith and Ruether, 1985;Kato et al, 1985). The results of this study show that for 34-m particles there is no significant variation in concentration and values are close to the average concentration at Average Concentration (Volume %) Fig.…”

Flow Characterization of a Three‐Phase Circulating Fluidized Bed Using an Ultrasonic Technique

“…In conventional fluidized beds, a uniform distribution of solid holdups is observed in the lower section of the beds whereas a gradual decrease appears near the bed top (a lean region), a transition from the main three-phase bed region to a liquid-gas region (Lee and de Lasa, 1987). In this lean region, the distribution of solid holdups follows an exponential function in axial direction (Kato et al, 1985). The cross-sectional averaged gas holdups in conventional threephase fluidized beds gradually increase along the bed height (Chen et al, 1995) and a bell-shaped gas holdup profile is seen in the radial direction (Lee and de Lasa, 1987;Schweitzer et al, 2001).…”

Transient discharge of solid particles from upper outlet of vertical bubble columns

“…Three-phase fluidization is an important technique for contacting gas, liquid, and solid particles and is widely used in petroleum and biochemical processes. Many works (Imafuku et al, 1968;Kato et al, 1972Kato et al, , 1985Smith and Ruether, 1985;Morooka et al, 1986;Smith et al, 1986;Murray and Fan, 1989;Matsumoto et al, 1989Matsumoto et al, , 1991Matsumoto et al, , 1992Hidaka et al, 1992) have been published on the behavior of solid particles in columns. Fan (1989) summarized results on fundamentals and applications of three-phase fluidization up to 1989.…”