Experimental Investigation into the Radial Distribution of Local Phase Holdups in a Gas−Liquid−Solid Fluidized Bed

Abstract

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.

Experimental Determination of Bubble Size Distributions in Laboratory Scale Sieve Tray with Mesh

“…The predecessors used the various measuring techniques that include conductivity probe, manometric method, dynamic gas disengagement technique (DGD), photographic technique method, and γ-ray computed tomography (CT). Taking advantage of different conductivity between gas and liquid, the conductivity probe could directly measure bubbles, especially when using a large sample, but data processing could be complicated . The manometric method was the usual method used to measure gas hold-up which was deduced from pressure difference.…”

“…Taking advantage of different conductivity between gas and liquid, the conductivity probe could directly measure bubbles, especially when using a large sample, but data processing could be complicated. 17 The manometric method was the usual method used to measure gas hold-up 18 which was deduced from pressure difference. DGD could be used in opaque systems.…”

Hydrodynamic Behaviors in Gas‐Solid Two‐Phase Magnetic Fluidized Beds 1. Experimental Results Represented by a Dimensionless Number

“…The gas voidage variation in the gas-solid two-phase fluidized beds is virtually important for estimating the real velocities and residence time distribution of each phase. Several methods have been proposed for the phase holdup measurements of two-phase magnetic field fluidized beds: (i) physical methods, i.e., pressure profile technique, quick-closing valve technique, and bed height measurement (overall phase holdup measurement) [14,15]; (ii) electrical capacitance and conductance method, i.e., electric conductivity probe technique (local holdup measurement) [16]; (iii) optical method, i.e., optical fiber probe (local phase holdup measurement) [17].…”