Hydrodynamics and mass transfer in three-phase fluidized beds with non-Newtonian fluids

✍ Scribed by H. Miura; Y. Kawase

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 538 KB
• Volume: 52
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/s0009-2509(97)00251-0

✦ Synopsis

Hydrodynamics and gas-liquid mass transfer in three-phase fluidized beds have been investigated. Particular attention has been paid to the influence of non-Newtonian flow behaviors of liquids on hydrodynamic characteristics and mass transfer rates. The minimum fluidization velocity, bed voidagc, gas holdup and gas liquid volumetric mass transfer coefficient were measured in a 0.068 m i.d. fluidized bed. Glass beads of three different sizes (3, 5 and 7 mm) were used. The minimum fluidization velocity decreased with increasing non-Newtonian flow behaviors. We proposed a new theoretical correlation for minimum fluidization velocity with non-Newtonian liquids, which is applicable to two-and three-phase fluidized beds in the whole region of the Reynolds number. It is developed on the basis of the free-surface cell concept. Reasonable agreement between the predictions and the experimental data for liquid-solid two-phase and gas-liquid-solid three-phasc systems was obtained. The bed voidage was found to increase due to non-Newtonian anomalies. The gas holdup decreased with increasing non-Newtonian flow behaviors and decreasing particle diameter. It was also found that the gas-liquid volumetric mass transfer coefficients in non-Newtonian liquids are smaller compared with those in water, i (' 1997