New technique for simultaneous measurement of the local solid and gas holdup by using optical fiber probes in the slurry bubble column

Mokhtari, Mojtaba; Chaouki, Jamal

doi:10.1016/j.cej.2018.10.067

Cited by 39 publications

(15 citation statements)

References 24 publications

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“…Indeed, at low Ug , the solid concentration in the region surrounding a bubble was not C v but C v ,local which is the local concentration near the bubble. Mokhtari et al found that the local solid concentration increases with superficial gas velocity until it reaches a plateau in the heterogeneous regime. It is this constant value that could be equal to the initial solid volume fraction C v .…”

Section: Resultsmentioning

confidence: 99%

Simultaneous effect of particle size and solid concentration on the hydrodynamics of slurry bubble column reactors

et al. 2019

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The simultaneous effect of particle size and concentration on the total gas holdup of slurry bubble column reactors was investigated in this work. The total gas holdup was measured for air-water-glass beads systems. Three solid concentrations and three particle diameters were used. It was found that increasing particle size at high constant concentration decreases gas holdup. Moreover, increasing solid concentration decreases gas holdup and this decreasing effect is higher for larger particles. Also, solid particles have two effects on hydrodynamics, namely, changing the viscosity and density of the liquid phase as well as hindering the bubbles from rising within the column by the collision phenomenon. Therefore, a novel correcting factor was introduced to correct the gas holdup. The hindering factor considers both the collision efficiency affected by the particle size as well as the solid concentration. A novel correlation was developed to predict the experimental data of the three-phase gas holdup.

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Section: Resultsmentioning

confidence: 99%

Simultaneous effect of particle size and solid concentration on the hydrodynamics of slurry bubble column reactors

et al. 2019

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“…In these processes, characterization of multiphase flow is an essential step to investigate bubble properties. Various techniques have been applied for this purpose, including high‐speed imaging, optical probe measurement, electrical capacitance tomography, and particle image velocimetry 26–30 . By contrast, high‐speed imaging has been paid more attention for its advantage of noninterference on the flow field 31,32 …”

Section: Introductionmentioning

confidence: 99%

The effect of inorganic salt on multiphase flow characteristics in a microbubble column: A focus on the ionic strength

Jia

Shen

et al. 2021

Asia-Pacific J Chem Eng

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With enormous interfacial area for particle collection, microbubbles exhibit great application prospect in the mineral flotation. Under certain ionic strength, microbubbles can be produced continuously in the microbubble column without extra reagent addition. In this work, multiphase flow characteristics (Sauter mean diameter, bubble size distribution, gas holdup & interfacial area) were studied systematically with variables including the salt type, salt concentration, and operating conditions. Based on mathematical model, critical coalescence concentration was determined for each investigated salt. According to experimental results, a mathematical correlation was established between the Sauter mean diameter and ionic strength. For the formation of microbubble system, the lowest ionic strength was approximately 0.5 mol/L. Multiphase flow characteristics in the microbubble column depended highly on the ionic strength. The interfacial area and gas holdup increased by 38 times and more than 3 times respectively, with the ionic strength of Al2(SO4)3 rising from 0 to 1.5 mol/L. The critical coalescence concentration ranged from 0.037 mol/L (Al2(SO4)3) to 0.517 mol/L (NaCl), which correlated with the ionic strength of each salt.

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“…In contrast, large particles with diameters in the millimeter range may lead to breakup when colliding with bubbles and result in an increase of the gas holdup (Fan et al, 2007). Amongst latest experimental investigations, detailed studies can be found on the characterization of the gas-phase dynamics (Tyagi and Buwa, 2017;Mokhtari and Chaouki, 2019;Sines et al, 2019) and solid-particle concentration distributions (MacIntyre et al, 2017;Abdullah, 2019) inside slurry bubble columns.…”

Section: Introductionmentioning

confidence: 99%

Modeling of solid-particle effects on bubble breakage and coalescence in slurry bubble columns

Mühlbauer

Hlawitschka

Bart

2020

Exp. Comput. Multiph. Flow

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Solid particles heavily affect the hydrodynamics in slurry bubble columns. The effects arise through varying breakup and coalescence behavior of the bubbles with the presence of solid particles where particles in the micrometer range lead to a promotion of coalescence in particular. To simulate the gas-liquid-solid flow in a slurry bubble column, the Eulerian multifluid approach can be employed to couple computational fluid dynamics (CFD) with the population balance equation (PBE) and thus to account for breakup and coalescence of bubbles.In this work, three approaches are presented to modify the breakup and coalescence models to account for enhanced coalescence in the coupled CFD-PBE framework. The approaches are applied to a reference simulation case with available experimental data. In addition, the impacts of the modifications on the simulated bubble size distribution (BSD) and the applicability of the approaches are evaluated. The capabilities as well as the differences and limits of the approaches are demonstrated and explained.

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New technique for simultaneous measurement of the local solid and gas holdup by using optical fiber probes in the slurry bubble column

Cited by 39 publications

References 24 publications

Simultaneous effect of particle size and solid concentration on the hydrodynamics of slurry bubble column reactors

Simultaneous effect of particle size and solid concentration on the hydrodynamics of slurry bubble column reactors

The effect of inorganic salt on multiphase flow characteristics in a microbubble column: A focus on the ionic strength

Modeling of solid-particle effects on bubble breakage and coalescence in slurry bubble columns

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