Experimental Investigation into the Radial Distribution of Local Phase Holdups in a Gas−Liquid−Solid Fluidized Bed
journal contributionposted on 23.05.2007, 00:00 by Changqing Cao, Mingyan Liu, Qingjie Guo
Experiments were conducted in a gas−liquid−solid fluidized bed (GLSFB), using two types of particles. The light particles were styrene-blend spheres 1.45 mm in diameter, with a density of 1264 kg/m3, whereas the heavy particles were spherical glass beads 0.48 and 1.25 mm in diameter, with a density of 2460 kg/m3. In both cases, compressed air and tap water and carboxymethyl cellulose sodium with concentrations of 0.05 and 0.20 wt % (CMCS) were used as the gas phase and liquid phase, respectively. Local holdups in the GLSFBs were measured simultaneously using an improved double-sensor micro-electric conductivity probe under different liquid viscosities, superficial gas velocity, superficial liquid velocity, and particle sizes. It was determined that local solid holdup decreased with increasing liquid viscosity, superficial gas velocity, and superficial liquid velocity, whereas the local solid holdup at the center increased as the particle size increased. A maximum value of local solid holdup existed at r/R = 0.75−0.85, whereas the minimum value of the local solid holdup was located at the wall region. Dimensionless correlations of local holdups were developed using measurement results. Calculation values using correlations are in reasonable agreement with the measurement data.