Suspension of buoyant particles in a three phase stirred tank

Bao, Yuyun; Hao, Zuoqiang; Gao, Zhengming; Shi, Litian; Smith, J. M.

doi:10.1016/j.ces.2004.10.040

Cited by 37 publications

(60 citation statements)

References 10 publications

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“…Frijilink et al (1990) showed that low solids concentrations (< 2 vol %) do not change the RPD curves significantly. The small changes in RPD with solids loading reported here are similar to those found in systems with buoyant particles (Bao et al, 2005). Figure 5 compares the performance of agitators using up-and down-pumping hydrofoils.…”

Section: Gas Dispersion and Solid Suspension 805supporting

confidence: 70%

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Gas Dispersion and Solid Suspension in a Three-Phase Stirred Tank With Multiple Impellers

Bao

Hao

Gao

et al. 2006

Chemical Engineering Communications

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Despite much research on gas-liquid-solid systems and their widespread application in industry, gas dispersion with solid suspension in multistage stirred reactors equipped with multiple impellers has received little attention. We report here the critical just-suspension impeller speed for different concentrations of solid particles, gas holdup, and shaft power in a vessel of 0.48 m diameter with four baffles and dished base. Five agitator configurations, each with three impellers mounted on a single shaft, have been used in the experiments. Two novel impeller designs were used, a deep hollow blade (semi-ellipse) disc turbine (HEDT) and four-wide-blade hydrofoil impellers. The hydrofoils were used in both up-pumping (WH U ) and down-pumping (WH D ) modes. Glass beads of 50 $ 150 lm diameter and density 2500 kg Á m À3 were suspended at solid volumetric concentrations of 1.5, 3, 6, 9, and 15%. Results show that these suspended solids have little effect on the relative power demand. Agitators using the HEDT radial dispersing impeller at the bottom have a higher relative power demand (RPD ¼ P G =P U ) than those with WH D or WH U as the lowest one. For all impeller combinations there is little or no effect on gas holdup with increasing solid concentrations. Of the five different impeller combinations, those with an axial flow bottom impeller have significantly higher just-suspension agitation speeds and power consumption, so mounting the hydrofoil impeller at the bottom is not the optimal configuration for particle suspension. Of these impeller combinations, at a given gas flow rate the arrangement of HEDT þ 2WH U has the highest relative power demand, gas holdup, and power input for both the suspension of settling particles and gas dispersion.

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Section: Gas Dispersion and Solid Suspension 805supporting

confidence: 70%

“…This article recommends optimal configurations for multistage gas-liquid stirred reactors with settling particles. The influence of solid concentration on the gas holdup presented and discussed here is quite different from that in a three-phase system with buoyant particles (Bao et al, 2005). …”

Section: Introductioncontrasting

confidence: 58%

Gas Dispersion and Solid Suspension in a Three-Phase Stirred Tank With Multiple Impellers

Bao

Hao

Gao

et al. 2006

Chemical Engineering Communications

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“…A number of studies focused on three phase systems; among these Nienow et al (1986), Frijlink et al (1990), Micale et al (2000) and Dohi et al (2004) addressed the problem of correlating the agitator speed for complete suspension under gassed conditions. Recently Kuzmanic and Ljubicic (2001), Bao et al (2005) and Tagawa et al (2006), investigated the draw-down of floating solid particles in aerated baffled vessels.…”

Section: Introductionmentioning

confidence: 99%

Particle suspension in top-covered unbaffled tanks

Brucato

Cipollina

Micale

et al. 2010

Chemical Engineering Science

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“…Particles less dense than the liquid will float onto the liquid surface (Etchells, 2001). Dispersion of floating particles in an agitated vessel is more sensitive to direction of the fluid circulation and arrangement and type of the baffles than settling of the particles (Bao et al, 2005;Karcz and Mackiewicz, 2006;2009;Ozcan-Taskin, 2006;Ozcan-Taskin and Wei, 2003). Mechanically agitated gas -liquid systems using single or more than one impeller on the common shaft have been intensively tested (Adamiak, 2005;Cudak, 2011;Montante et al, 2006;Moucha et al, 2003;Nienow and Lilly, 1996;Warmoeskerken, 1986).…”

Section: Introductionmentioning

confidence: 99%

Influence of different factors on momentum transfer in mechanically agitated multiphase systems

Cudak¹,

Kiełbus-Rąpała²,

Major-Godlewska³

et al. 2016

Chemical and Process Engineering

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A comparative analysis concerning the influence of different factors on momentum transfer in mechanically agitated systems was carried out on the basis of experimental results for solid-liquid, gas-liquid and gas-solid-liquid systems. The effects of the impeller -baffles system geometry, scale of the agitated vessel, type and number of impellers and their off-bottom clearance, as well as physical properties of the multiphase systems on the critical impeller speeds needed to produce suspension or dispersion, power consumption and gas hold-up were analysed and evaluated.

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Suspension of buoyant particles in a three phase stirred tank

Cited by 37 publications

References 10 publications

Gas Dispersion and Solid Suspension in a Three-Phase Stirred Tank With Multiple Impellers

Gas Dispersion and Solid Suspension in a Three-Phase Stirred Tank With Multiple Impellers

Particle suspension in top-covered unbaffled tanks

Influence of different factors on momentum transfer in mechanically agitated multiphase systems

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