## Phase Holdups in Three-Phase Fluidized Beds The local bubble frequency, the local phase holdups and the local bed porosity in three-phase fluidized beds were measured. Air, water, and 250 pm glass beads were used as the gas, liquid, and solid phases. The effects of gas and liquid velocities on
Distributions of flow regimes and phase holdups in three-phase fluidized beds
โ Scribed by Zumao Chen; Chong Zheng; Yuanding Feng; Hanns Hofmann
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 461 KB
- Volume
- 50
- Category
- Article
- ISSN
- 0009-2509
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โฆ Synopsis
AMtract--Pressure fluctuation characteristics at different axial and radial positions were investigated in a three-phase fluidized-bed Plexiglas column of 285 mm inside diameter and 4100 mm height operated with air, tap water and glass beads under different conditions. It was found that the whole column may display different flow regimes depending on the operating conditions, i.e. total homogeneous bubble regime, total transition regime, total turbulent bubble regime, while the two neighbouring or all three regimes may exist simultaneously at different heights of the column. Schemes of flow regime distribution, which changes with gas velocity, were given, and the criteria for flow regimes correlated with operating variables and axial distance above the gas distributor were established. It was also found that any flow regime was substantially identical at different radial positions across the column. Phase holdups at different heights of the column were measured by means of a combination of pressure drop and sampling methods. Correlations of gas and solid holdup in different flow regimes as a function of operating parameters and axial distance from the distributor were established.
๐ SIMILAR VOLUMES
The volumetric gas-liquid mass transfer coefficient (KLa) and axial dispersion coefficient (Dz) of liquid phase have been studied in air-oxygen saturated water fluidized beds of 0.52 to 0.755 mm glass spheres in a plexiglass column. The effects of liquid velocity, gas velocity, particle size and loa
A mechanistic model developed based on modification of the concept underlying the classical wake model (CWM), more specifically the generalized wake model, is presented to account for the phase holdup behavior in gas-liquid-solid fluidized beds. The CWM is characterized by two parameters, namely, th