Prediction of mass transfer coefficients in a pulsed packed extraction column using effective diffusivity

Torab‐Mostaedi, Meisam; Safdari, Jaber

doi:10.1590/s0104-66322009000400007

Cited by 33 publications

(10 citation statements)

References 19 publications

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“…Increasing the dispersed phase flow rate caused increasing holdup and drop size. Holdup has a positive effect and drop size has a negative effect on the interfacial area, however, as was revealed by Torab‐Mostaedi and Safdari, holdup has a more significant impact on the interfacial area than the drop size; as a result. the interfacial area is increased and, consequently, more solute can be transferred.…”

Section: Resultsmentioning

confidence: 86%

Use of axial dispersion and plug flow models for determination of axial mixing and mass transfer coefficient in an l‐shaped pulsed packed extraction column

et al. 2019

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In this study, the volumetric overall mass transfer and phases axial mixing coefficients have been investigated in a pilot plant of an L‐shaped pulsed packed extraction column by using two liquid systems of toluene/acetone/water and n‐butyl/acetone/water. The mass transfer performance has been evaluated using two methods of axial dispersion and a plug flow model. The effect of the operational variables and physical properties, including the dispersed and continuous phases flow rates, pulsation intensity, and interfacial tension, on mass transfer and phases axial mixing coefficients have been considered. It has been found that the pulsation intensity and the continuous phase flow rate seriously affect the mass transfer coefficient, however, the dispersed phase flow rate has a weaker effect. Also, the axial mixing of a phase is strongly affected by the pulsation intensity and the flow rate of the phase itself and it is not affected by the second phase flow rate. Finally, new correlations are proposed to accurately predict the mass transfer and axial mixing coefficients.

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Section: Resultsmentioning

confidence: 86%

Use of axial dispersion and plug flow models for determination of axial mixing and mass transfer coefficient in an l‐shaped pulsed packed extraction column

et al. 2019

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“…This correlation was for all experiments with a variety of properties such as mass transfer resistance and interfacial tension. Also Temos et al, Mostaedi and Safdari, and recently Rahbar et al proposed several empirical correlations for prediction of the enhancement factor in different extraction columns. The method has considerable advantage over direct correlation of the mass transfer coefficient, eliminating difficulties with time dependency and working on the effective diffusivity which is not usually dependent on contact time …”

Section: Resultsmentioning

confidence: 99%

“…The organic phase was held in a glass syringe conducted by an adjustable syringe pump (JMS SP-500, Japan) and flowed through a rigid tube to the glass nozzle. The column containing aqueous phase and conducting tubes was thermostatted to reach the desired temperature (15,20,25,30,35, and 40 °C), with an uncertainty of ±0.1 °C. This was established using an adjustable safe and calibrated thermostat (Julabo F12, German), the syringe and the connection tube to the nozzle tip were first filled with organic phase to produce drops, and the column was then filled with deionized water as the continuous phase.…”

Section: Methodsmentioning

confidence: 99%

Mass Transfer from Single Drops and the Influence of Temperature

Saien

Daliri

2012

Ind. Eng. Chem. Res.

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Temperature can alter the performance of conventional liquid–liquid extraction columns in which one phase is dispersed inside another phase. In this research, the influence of temperature on the extraction process was investigated using a toluene–acetic acid–water chemical system with dominant mass transfer resistance in the organic phase. Single drop experiments with a range of drop size within 2.49–3.77 mm and temperature within 15–40 °C were performed. Results demonstrate significant impact of temperature on the rate of mass transfer with an average enhancement of 93.6% in overall mass transfer coefficient while small drops are benefited more. Having lower contributions by drop size and terminal velocity, the extraction efficiency is the most effective term in this regard which itself is increased by increasing molecular diffusivity in the organic dispersed phase. For the aim of modeling, effective diffusivity was substituted for molecular diffusivity in Newman’s equation and consequently, a reliable empirical equation was derived for the enhancement factor of diffusivity as a function of dimensionless variables.

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“…In the liquid-liquid extraction step, extraction columns with high removal capability for sulfurcontaining compounds should be applied. Various extraction columns, including a rotating disk contactor (Torab-Mostaedi et al, 2017;Asadollahzadeh et al, 2016), Kuhni column (Hemmati et al, 2015;Arab et al, 2017;Oliveira et al, 2008), packed column (Rahbar-Kelishami and Bahmanyar, 2012;Torab-Mostaedi and Safdari, 2009), pulsed column (Amani et al, 2017;Khooshechin et al, 2013;Usman et al, 2009), tray column (Sincuba et al, 2017), and spray column (Salimi-Khorshidi et al, 2013), are available. Single drop tests can provide valuable insights regarding the hydrodynamics of the complex systems in the liquidliquid extraction.…”

Section: Introductionmentioning

confidence: 99%

Separation of Sulfur-Containing Compounds From Diesel by Oxidation Followed by Solvent Extraction in a Single Drop Column

Dana

Sobati

Shahhosseini

et al. 2019

Braz. J. Chem. Eng.

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Oxidative desulfurization (ODS) is an attractive complementary or alternative process for the hydrodesulfurization (HDS) process due to advantages such as mild operating conditions. In the ODS process, the sulfur-containing compounds are oxidized first to polar sulfoxide and sulfone products and then these polar compounds are separated using solvent extraction or an adsorption process. In the present study, the separation of oxidized sulfur-containing compounds of diesel as a real fuel has been investigated using extraction in a single drop column. The oxidation system was hydrogen peroxide/formic acid. The selected solvent for the extraction of oxidized sulfur-containing compounds was dimethylformamide (DMF). In single drop tests, the effect of various parameters including the drop size (1.70-4.60 mm) and column height (228-550 mm) on the different parameters such as drop velocity and sulfur concentration in the dispersed and continuous phases has been investigated. The outcome of this study provides valuable insights for designing the extraction column for separation of oxidized sulfur-containing compounds from middle distillate fuels in an ODS process.

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Prediction of mass transfer coefficients in a pulsed packed extraction column using effective diffusivity

Cited by 33 publications

References 19 publications

Use of axial dispersion and plug flow models for determination of axial mixing and mass transfer coefficient in an l‐shaped pulsed packed extraction column

Use of axial dispersion and plug flow models for determination of axial mixing and mass transfer coefficient in an l‐shaped pulsed packed extraction column

Mass Transfer from Single Drops and the Influence of Temperature

Separation of Sulfur-Containing Compounds From Diesel by Oxidation Followed by Solvent Extraction in a Single Drop Column

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