Mass transfer coefficient determination in three biphasic systems (water–ionic liquid) using a modified Lewis cell

Determination of mass transfer coefficients in high-pressure two-phase flows in capillaries using Raman spectroscopy

Kinetic, oxygen mass transfer and hydrodynamic studies in a three-phase stirred tank bioreactor for the bioconversion of (+)-valencene on Yarrowia lipolytica 2.2ab

The volumetric overall mass transfer coefficients in a pilot plant Hanson mixer-settler extraction column of seven stages have been measured using toluene-acetone-water system. The effects of agitation speed and dispersed and continuous phases flow rates on volumetric overall mass transfer coefficients have been investigated. The results show that the volumetric overall mass transfer coefficient increases with increase in agitation speed and reaches a maximum. After having reached its maximum, it falls with further increase in agitation speed. It was found that the volumetric overall mass transfer coefficient increases with increase in dispersed phase flow rate, while it decreases with increase in continuous phase flow rate. By using interfacial area, the overall mass transfer coefficients for continuous and dispersed phases are determined from volumetric coefficients. An empirical correlation for prediction of the continuous phase overall mass transfer coefficient is proposed in terms of Sherwood and Reynolds numbers. Also the experimental data of the column investigated are compared with data for various extraction columns. Comparison between theoretical models and experimental results for the dispersed phase mass transfer coefficient shows that these models do not have enough accuracy for column design. Using effective diffusivity in the Grober equation results in more accurate prediction of overall mass transfer coefficient. The prediction of overall mass transfer coefficients from the presented equations is in good agreement with experimental results.

In this work, gas dispersion in a two-phase partitioning bioreactor is analyzed by calculating volumetric oxygen mass transfer coefficient which is modeled using a commercial computational fluid dynamics (CFD), code FLUENT 6.2. Dispersed oxygen bubbles dynamics is based on standard "k-ε" Reynolds-averaged Navier-Stokes (RANS) model. This paper describes a three-dimensional CFD model coupled with population balance equations (PBE) in order to get more confirming results of experimental measurements. Values of k L a are obtained using dynamic gassing-out method. Using the CFD simulation, the volumetric mass transfer coefficient is calculated based on Higbie's penetration theory. Characteristics of mass transfer coefficient are investigated for five configurations of impeller and three different aeration flow rates. The pitched six blade type, due to the creation of downward flow direction, leads to higher dissolved oxygen (DO) concentrations, thereby, higher values of k L a compared with other impeller compositions. The magnitude of dissolved oxygen percentage in the aqueous phase has direct correlation with impeller speed and any increase of the aeration magnitude leads to faster saturation in shorter periods of time. Agitation speeds of 300 to 800rpm are found to be the most effective rotational speeds for the mass transfer of oxygen in two-phase partitioning bioreactors (TPPB).

The volumetric liquid‐phase mass transfer coefficient, kLa, was determined by absorption of oxygen in air using six different carboxy‐methyl cellulose (CMC) solutions with different rheological values in three phase spout‐fluid beds operated continuously with respect to both gas and liquid. Three cylindrical columns of 7.4 cm, 11.4 cm, and 14.4 cm diameters were used. Gas velocity was varied between 0.00154–0.00563 m/s, liquid velocity between 0.0116–0.0387 m/s, surface tension between 0.00416–0.0189 N/m, static bed height between 6.0–10.8 cm, and spherical glass particles of 1.75 mm diameter were used as packing material. A single nozzle sparger of 1.0 cm diameter was used in the spouting line. The volumetric mass transfer coefficient was found to increase with gas velocity, liquid velocity, and static bed height and to decrease with the increase of the effective liquid viscosity of the CMC solution. A dimensionless correlation was developed and compared with those listed in the literature.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTGas-liquid interfacial area and liquid-side mass-transfer coefficient in a slurry bubble columnEizo Sada, Hidehiro Kumazawa, Choul Ho Lee, and Hiroaki NarukawaCite this: Ind. Eng. Chem. Res. 1987, 26, 1, 112–116Publication Date (Print):January 1, 1987Publication History Published online1 May 2002Published inissue 1 January 1987https://pubs.acs.org/doi/10.1021/ie00061a022https://doi.org/10.1021/ie00061a022research-articleACS PublicationsRequest reuse permissionsArticle Views449Altmetric-Citations32LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

liquid-liquid extraction in a mixer tank was widely used to reach a certain mass transfer rate. Mass transfer rate in a mixer tank extractor is declared as mass transfer coefficient. This research intends to learn how mass transfer coefficient does in a mixer tank extractor and variables that influence mass transfer coefficient. Determination of mass transfer coefficient in a mixer tank extractor is a function of mixer rate and characteristic of physical system. This system study about water – acetic acid – methyl acetic between CMC as a phase concentration in a solvent. The influences of variable to mass transfer coefficient in a equation of non-dimention group is; Sh=7396.05 Re 0.82 Sch -0.35 . For whirlmixer, rate is between 1 to 4 circle/s and solvent viscosity is between 1 to 6.18 cP, and for whirlReynold, rate is between 2500 to 1000 and whirlSchmidt is between 689.655 to 4262.07.

Gas–liquid mixing in a multi-scale micromixer with arborescence structure

Gas absorption in aqueous solutions with Tween 80 and absorption processes based on hydrodynamics and mass transfer is determined. The impact of surfactant concentration on gas holdup and gas‐liquid interfacial area is analyzed, observing an increase of these parameters with surfactant concentration. The influence of liquid‐phase contamination on the absorption process is investigated on the basis of the liquid‐film mass transfer coefficient, removing the effect caused by the presence of a surfactant and the gas flow rate on the interfacial area and, thereby, on the volumetric mass transfer coefficient. The opposite effect on the mass transfer coefficient can be observed which decreases in the presence of the surfactant.

Mass transfer studies in shallow bubble column reactors

Enhanced gas-liquid mass transfer coefficient by bulk nanobubbles in water

In the present work, multistage extraction column performance for reactive separation of molybdenum from the leach aqueous phase by using D2EHPA and TBP in kerosene was investigated by using axial diffusion model. Initially, the values of initial pH and extractant concentration were optimized on the batch experiments. The variation of volumetric overall mass transfer coefficients based on continuous phase at various operating conditions was obtained. By considering the chemical reaction conditions, the experimental data indicate that the volumetric overall mass transfer coefficients increase with an enhancement in rotor speed and continuous and dispersed phase flow rates. According to the sensitivity analysis, the rotor speed and flow rate of dispersed phase have more influence on column performance. Also, the continuous flow rate has little effect on volumetric overall mass transfer coefficients. After the steady-state condition was established, the concentration profile for the extraction of molybdenum along the column was obtained. The experimental data were studied and compared with the previous models. A new model based on dimensionless numbers was derived from the evaluation of overall mass transfer coefficients with consideration of the reactive extraction system.

The correct mathematical description and a suggested solution method for a model in packed columns A note on “A new technique for the determination of mass transfer coefficients in packed columns for physical gas absorption systems” [Chem. Eng. J., 57 (1995) 67

An experimental breakthrough curve for Salicylic acid in an adsorption recovery process was determined by an anion-exchange resin IRA-93. The volumetric mass transfer coefficients were calculated by employing constant wave propagation theory. Meanwhile, the effects of volumetric feed flow rates on this break through curve and mass transfer coefficients at different flow rates were also studied in order to develop three new models to predict mass transfer coefficient. The results demonstrated that by the increase in the feed flow rates, the amount of adsorption reduces. However, while the volumetric feed flow rates increase the overall volumetric mass transfer coefficients will increase. This grows the feeling that the feed flow rate should be optimized. The optimum flow rate for the adsorption was found to be 7 mg/l in this study. In addition, three new models to predict the mass transfer coefficient in respect of feed rates were developed in this research work which showed very high fittings with R2>0.99. These models could fully support the experimental data obtained.

Effect of the radical scavenger t-butanol on gas–liquid mass transfer