Dispersed Phase Hold-up in a Vertical Mixer Settler in With and Without Mass Transfer Conditions

Bahmanyar, Hossein; Ghasempour, Farideh; Safdari, Jaber

doi:10.1252/jcej.40.17

Cited by 6 publications

(3 citation statements)

References 6 publications

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“…When the direction of mass transfer is from the continuous phase to the dispersed phase, the solute concentration in the wake of the droplet is larger than that at the top of the droplet; the consequence of the resulting interfacial tension gradient is that the interface moves opposite to the direction of the inner circulation generated inside the droplet. Therefore, it is expected that the interface deformations due to this mass-transfer direction enhance the droplet deformation, that is, the break-up process. , Moreover, during solute transfer from the continuous phase to the dispersed phase, solute equilibrium is quickly established between the droplets and the continuous phase, whereas solute transfer continues over the rest of the droplet surface. This creates an interfacial tension gradient, which opposes the forces causing drainage in the film, thus reducing coalescence.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, it is expected that the interface deformations due to this mass-transfer direction enhance the droplet deformation, that is, the break-up process. 25,64 Moreover, during solute transfer from the continuous phase to the dispersed phase, solute equilibrium is quickly established between the droplets and the continuous phase, whereas solute transfer continues over the rest of the droplet surface. This creates an interfacial tension gradient, which opposes the forces causing drainage in the film, thus reducing coalescence.…”

Section: Steady-statementioning

confidence: 99%

See 1 more Smart Citation

Population Balance Modeling of Pulsed (Packed and Sieve-Plate) Extraction Columns: Coupled Hydrodynamic and Mass Transfer

Jaradat

Attarakih

Bart

2011

Ind. Eng. Chem. Res.

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Liquid–Liquid Extraction Column Module (LLECMOD) is a rigorous and comprehensive bivariate population balance framework for dynamic and steady-state modeling of liquid–liquid extraction columns. Within LLECMOD, the user can simulate different types of extraction columns, including stirred and pulsed ones. The basis of LLECMOD depends on stable robust numerical algorithms based on an extended version of a fixed pivot technique (to take into account interphase solute transfer) and advanced computational fluid dynamics (CFD) numerical methods. In this work, mathematical models for pulsed packed and sieve tray extraction columns are developed. The models are programmed using visual digital FORTRAN and then integrated into the LLECMOD population balance model. As a case study, the steady-state performance of pulsed packed and sieve-plate columns, under different operating conditions, which include pulsation intensity and volumetric flow rates, are simulated. The effect of pulsation intensity is found to have a more profound effect on systems of high interfacial tension. On the other hand, the variation of volumetric flow rates has a substantial effect on the holdup, mean droplet diameter, and solute concentration profiles for chemical systems with low interfacial tension. Two chemical test systems recommended by the EFCE are used in the simulations. Model predictions are successfully validated against experimental data by adjusting the steady-state column hydrodynamics, using only droplet coalescence empirical parameters.

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Section: Resultsmentioning

confidence: 99%

Section: Steady-statementioning

confidence: 99%

Population Balance Modeling of Pulsed (Packed and Sieve-Plate) Extraction Columns: Coupled Hydrodynamic and Mass Transfer

Jaradat

Attarakih

Bart

2011

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

show abstract

“…Therefore, droplet size distribution (DSD) needs to be employed to address this issue. DSD can not only determine the mass transfer area but also effect interphase force and residence time of the dispersed phase in the mixer. , The evolution of DSD in a multiphase system can be numerically described by solving the population balance equation (PBE) . For PBE with only one internal-coordinate, namely the monovariable problem, the most widely adopted approaches are the moment methods and the method of classes .…”

Section: Introductionmentioning

confidence: 99%

CFD-PBE Simulation of Flow Dynamics and Mass Transfer in Two-Stage Countercurrent Mixer-Settler

Zheng

Yang

Xiao

et al. 2023

Ind. Eng. Chem. Res.

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Flow condition and mass transfer behavior of liquid−liquid extraction in a two-stage countercurrent extractor are investigated experimentally and numerically. CFD-PBE simulation is adopted to analyze the impact of operating parameters, including impeller speed, residence time, and organic-aqueous ratio of feed flow on volume fraction and droplet size of dispersed phase and volumetric mass transfer coefficient. Droplet size distribution is calculated by considering breakage and coalescence of dispersed phase. The allocation of dispersed phase between stages is found to be determined by impeller speed. Meanwhile, the allocation of dispersed phase between mixers and settlers is governed by residence time and organic-aqueous ratio of feed flow. Turbulence intensity, volume fraction, and droplet size distribution are revealed to be dominating parameters that affect the spatial nonuniform distribution of volumetric mass transfer coefficient. The mass transfer rate can be improved by increasing impeller speed in two stages. Higher residence time and organic-aqueous ratio of feed flow, however, have opposite effects on mass transfer rate in stage-1 and stage-2.

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Dispersed phase holdup and slip velocity of phases in a pulsed packed column in conditions with and without mass transfer

et al. 2009

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Dispersed phase holdup and slip velocity of phases were measured in a pilot plant pulsed packed column with a diameter of 76.2 mm for two different chemical systems in conditions with and without mass transfer. The effects of pulsation intensity, dispersed and continuous phases flow rates, interfacial tension and solute concentration on dispersed phase holdup and slip velocity of phases were investigated. A new empirical correlation in terms of the above-mentioned parameters developed from the measurements is given for the prediction of slip velocity. The dispersed phase holdup was calculated by means of this correlation and very good agreement between calculated and experimental values was obtained.On a mesuré la retenue de la phase dispersée et la vitesse de glissement des phases dans une colonne pulséeà garnissage d'une usine pilote, d'un diamètre de 76,2 mm pour deux systèmes chimiques avec et sans transfert de masse. On a examiné les effets de l'intensité des pulsations, des débits des phases dispersées et continues, la tension interfaciale et la concentration des solutés sur la retenue de phase dispersée et la vitesse de glissement des phases. Une nouvelle corrélation empirique fondée sur les paramètres décrits ci-dessusà partir des mesures est donnée aux fins de la prédiction de la vitesse de glissement. On a calculé la retenue de phase dispersée au moyen de cette corrélation et obtenu une très bonne concordance entre les valeurs calculées et expérimentales.

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Dispersed Phase Hold-up in a Vertical Mixer Settler in With and Without Mass Transfer Conditions

Cited by 6 publications

References 6 publications

Population Balance Modeling of Pulsed (Packed and Sieve-Plate) Extraction Columns: Coupled Hydrodynamic and Mass Transfer

Population Balance Modeling of Pulsed (Packed and Sieve-Plate) Extraction Columns: Coupled Hydrodynamic and Mass Transfer

CFD-PBE Simulation of Flow Dynamics and Mass Transfer in Two-Stage Countercurrent Mixer-Settler

Dispersed phase holdup and slip velocity of phases in a pulsed packed column in conditions with and without mass transfer

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