Membrane-based solvent extraction of sulfur aroma compounds: influence of operating conditions on mass transfer coefficients in a hollow fiber contactor

AbstractA general review on correlations to evaluate mass transfer coefficients in liquid-liquid was conducted in this work. The mass transfer models can be classified into continuous and dispersed phase coefficients. The effects of drop size and interfacial area on mass transfer coefficient were investigated briefly. Published experimental results for both continuous and dispersed phase mass transfer coefficients through different hydrodynamic conditions were considered and the results were compared. The suitability and drawbacks of these correlations depend on the operating conditions and hydrodynamics. Although the results of these models are reasonably acceptable, they could not properly predict the experimental results over a wide range of designs and operating conditions. Therefore, proper understanding of various factors affecting mass transfer coefficient needs to be further extended.

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The flow and mass transfer characteristics of concentric gas-liquid flow in an advanced static mixer

Chemical Industry and Chemical Engineering Quarterly ◽

10.2298/ciceq191213024m ◽

2020 ◽

pp. 24-24

Author(s):

Huibo Meng ◽

Zhonggen Li ◽

Yanfang Yu ◽

Mengqi Han ◽

Shuning Song ◽

...

Keyword(s):

Mass Transfer ◽

Liquid Flow ◽

Operating Conditions ◽

Static Mixer ◽

Transfer Coefficients ◽

Mass Transfer Coefficients ◽

Local Mass ◽

Transfer Characteristics ◽

Local Mass Transfer ◽

Gas Liquid Flow

The fluid dynamic and mass transfer characteristics of concentric upward gas-liquid flow were studied in the industrial static mixer with four equally spaced helical inserts (FKSM). The numerical simulations of gas volume fraction in Kenics mixer had a good agreement with the numerical and experimental results provided by Rabha et al. The characteristics of radial gas void fraction and local mass transfer coefficients in the FKSM were evaluated under different operating conditions. The velocity profiles of concentric air phase accelerated by the bubble forces firstly became sharp and narrow until z/l=-3.27 and then slowly decreased and stabilized at z/l=-1.5 before entering the first mixing element. Some extra unimodal profile of radial gas holdup gradually generated near the rectangle cross sections of mixing elements. The ?G gradually enlarged from r/R=0.2 to r/R=0.55 and then weakened from r/R=0.65 to r/R=0.874. The air void fractions in the bulk flow region decreased with the increasing initial uniform bubble diameter. The inlet effect of first leading edge enhanced the air phase dispersion and local mass transfer coefficients sharply increased from 2.04 to 3.69 times of that in the inlet. The local mass transfer coefficients in each mixing group had unimodal profiles.

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Influence of Hydraulic Pressure on Performance Deterioration of Direct Contact Membrane Distillation (DCMD) Process

Membranes ◽

10.3390/membranes9030037 ◽

2019 ◽

Vol 9 (3) ◽

pp. 37 ◽

Cited By ~ 7

Author(s):

Seung-Min Park ◽

Sangho Lee

Keyword(s):

Mass Transfer ◽

Direct Contact ◽

Membrane Distillation ◽

Operating Conditions ◽

Hydraulic Pressure ◽

Transfer Coefficients ◽

Hydrophobic Membrane ◽

Mass Transfer Coefficients ◽

Efficient Operation ◽

Direct Contact Membrane Distillation

Direct contact membrane distillation (DCMD) is a membrane distillation (MD) configuration where feed and distillate directly contact with a hydrophobic membrane. Depending on its operating conditions, the hydraulic pressures of the feed and distillate may be different, leading to adverse effects on the performance of the DCMD process. Nevertheless, little information is available on how hydraulic pressure affects the efficiency of DCMD. Accordingly, this paper investigates the effect of external hydraulic pressure on the process efficiency of DCMD. Gas permeabilities of MD membranes were measured to analyze the effect of membrane compaction by external pressure. Mass transfer coefficients were calculated using experimental data to quantitatively explain the pressure effect. Experiments were also carried out using a laboratory-scale DCMD set-up. After applying the pressure, the cross-sections and surfaces of the membranes were examined using a scanning electron microscope (SEM). Results showed that the membrane structural parameters such as porosity and thickness were changed under relatively high pressure conditions (>30 kPa), leading to reduction in flux. The mass transfer coefficients were also significantly influenced by the hydraulic pressure. Moreover, local wetting of the membranes were observed even below the liquid entry pressure (LEP), which decreased the rejection of salts. These results suggest that the control of hydraulic pressure is important for efficient operation of DCMD process.

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Corrections to Correlations for Shell-Side Mass-Transfer Coefficients in the Hollow-Fiber Membrane (HFM) Modules

Industrial & Engineering Chemistry Research ◽

10.1021/ie040265c ◽

2005 ◽

Vol 44 (20) ◽

pp. 7835-7843 ◽

Cited By ~ 5

Author(s):

Tsun-teng Liang ◽

Richard L. Long

Keyword(s):

Mass Transfer ◽

Hollow Fiber ◽

Hollow Fiber Membrane ◽

Fiber Membrane ◽

Transfer Coefficients ◽

Shell Side ◽

Mass Transfer Coefficients

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The Need for Accurate Osmotic Pressure and Mass Transfer Resistances in Modeling Osmotically Driven Membrane Processes

Membranes ◽

10.3390/membranes11020128 ◽

2021 ◽

Vol 11 (2) ◽

pp. 128

Author(s):

Endre Nagy ◽

Imre Hegedüs ◽

Danyal Rehman ◽

Quantum J. Wei ◽

Yvana D. Ahdab ◽

...

Keyword(s):

Mass Transfer ◽

Osmotic Pressure ◽

Water Flux ◽

Operating Conditions ◽

Structural Parameter ◽

External Mass Transfer ◽

Transfer Coefficients ◽

Mass Transfer Coefficients ◽

The Real ◽

Parameter Values

The widely used van ’t Hoff linear relation for predicting the osmotic pressure of NaCl solutions may result in errors in the evaluation of key system parameters, which depend on osmotic pressure, in pressure-retarded osmosis and forward osmosis. In this paper, the linear van ’t Hoff approach is compared to the solutions using OLI Stream Analyzer, which gives the real osmotic pressure values. Various dilutions of NaCl solutions, including the lower solute concentrations typical of river water, are considered. Our results indicate that the disparity in the predicted osmotic pressure of the two considered methods can reach 30%, depending on the solute concentration, while that in the predicted power density can exceed over 50%. New experimental results are obtained for NanoH2O and Porifera membranes, and theoretical equations are also developed. Results show that discrepancies arise when using the van ’t Hoff equation, compared to the OLI method. At higher NaCl concentrations (C > 1.5 M), the deviation between the linear approach and the real values increases gradually, likely indicative of a larger error in van ’t Hoff predictions. The difference in structural parameter values predicted by the two evaluation methods is also significant; it can exceed the typical 50–70% range, depending on the operating conditions. We find that the external mass transfer coefficients should be considered in the evaluation of the structural parameter in order to avoid overestimating its value. Consequently, measured water flux and predicted structural parameter values from our own and literature measurements are recalculated with the OLI software to account for external mass transfer coefficients.

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Mass transfer coefficients of extracting Mo (VI) and W (VI) in a stirred tank by solvent extraction using mixture of Cyanex272 and D2EHPA

Separation Science and Technology ◽

10.1080/01496395.2019.1672741 ◽

2019 ◽

Vol 55 (17) ◽

pp. 3140-3150 ◽

Cited By ~ 3

Author(s):

Benyamin Shakib ◽

Meisam Torab-Mostaedi ◽

Mohammad Outokesh ◽

Mehdi Asadollahzadeh

Keyword(s):

Mass Transfer ◽

Solvent Extraction ◽

Stirred Tank ◽

Transfer Coefficients ◽

Mass Transfer Coefficients

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Mass Transfer Coefficients of Uranium and Plutonium across Aqueous/Organic Interfaces of Solvent Extraction

Journal of Nuclear Science and Technology ◽

10.1080/18811248.1986.9735016 ◽

1986 ◽

Vol 23 (6) ◽

pp. 529-539 ◽

Cited By ~ 5

Author(s):

Teruo MATSUDA ◽

Kozo GONDA

Keyword(s):

Mass Transfer ◽

Solvent Extraction ◽

Transfer Coefficients ◽

Mass Transfer Coefficients ◽

Organic Interfaces

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Probing Differences in Mass-Transfer Coefficients in Beaker and Stirrer Digestion Systems and the USP Dissolution Apparatus 2 Using Benzoic Acid Tablets

Processes ◽

10.3390/pr9122168 ◽

2021 ◽

Vol 9 (12) ◽

pp. 2168

Author(s):

Timothy A. G. Langrish ◽

Chao Zhong ◽

Lizhe Sun

Keyword(s):

Mass Transfer ◽

Benzoic Acid ◽

Reynolds Numbers ◽

Operating Conditions ◽

External Mass Transfer ◽

Transfer Coefficients ◽

Mass Transfer Coefficients ◽

Rate Limiting Step ◽

Dissolution Apparatus ◽

Rate Limiting

Measurements of external mass-transfer coefficients for dissolution have been made with benzoic acid tablets with a diameter of 13 mm and approximately 3 mm thick, using two different dissolution systems. One system has been a beaker with a platform for the tablet and either 80 mL or 120 mL of water, with three different types of stirrers, and the other has been a USP dissolution apparatus 2 (paddle) with either 200 mL or 900 mL water. Various stirring speeds have also been used in the different pieces of equipment. The same mass-transfer coefficient may potentially be obtained from the same tablet by adjusting the operating conditions in the two different devices. The ranges of the external mass-transfer coefficients measured in both devices overlapped significantly, with the range being 0.193–4.48 × 10−5 m s−1 in the beaker and stirrer system and 0.222–3.45 × 10−5 m s−1 in the USP dissolution apparatus 2. Dimensional analysis of the results, using Sherwood and Reynolds numbers, shows that the Ranz–Marshall correlation provides a lower bound for estimates of the Sherwood numbers measured experimentally. Calculations of time constants for mass transfer suggest that mass transfer may be a rate-limiting step for dissolution and food digestion under some circumstances. The range of mass-transfer coefficients measured here is representative of other measurements from the literature, and the use of the Ranz–Marshall correlation supports the suggestion that this range of values should be generally expected in most situations.

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