scholarly journals Hydrodynamics and mass transfer in Kühni extraction columns

2021 ◽  
pp. 14-14
Author(s):  
Milan Sovilj ◽  
Momcilo Spasojevic
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Dispersed Phase ◽  
Drop Diameter ◽  
Phase System ◽  
Rotor Speed ◽  
Empirical Correlations ◽  
Dimensionless Numbers ◽  
Transfer Direction

This work provides a review of hydrodynamic characteristics and mass transfer in the K?hni extraction columns. The experiments, as reported in the literature, were performed in the presence and absence of mass transfer. The results showed that the Sauter mean drop diameter was strongly affected by the rotor speed and interfacial tension, whereas the effects of the dispersed and continuous velocities were negligible. Empirical correlations for the Sauter mean drop diameter, taken from the literature, were discussed. It was experimentally determined that the dispersed-phase holdup depended to a great extent on the rotor speed, mass transfer direction between the phases, physical characteristics of fluids in the liquid-liquid system, and the dispersed-phase flowrate whereas it increased with the increase in mixing in the two-phase system and the ratio of phase flowrates. On the other hand, it has been shown that the mass transfer rate increases with increasing the level of back mixing. It was found that the mass transfer coefficient depends on the rotor speed and the direction of mass transfer between the phases. At the same time, it has been shown that the mass transfer coefficient depends relatively little on the phase flowrates. An empirical correlation was proposed for prediction of the overall mass transfer coefficient based on dimensionless numbers. Also, novel empirical correlations for prediction of the Sherwood number in the continuous phase were presented based on the dispersed-phase holdup, Reynolds number, and mass transfer direction between the phases. Empirical correlations based on dimensionless numbers can be considered as a useful tool for the design of the K?hni columns.

Liquid-liquid mass transfer studies in various stirred vessel designs

2015 ◽  
Vol 31 (4) ◽  
Author(s):  
Reza Afshar Ghotli ◽  
Abdul Raman Abdul Aziz ◽  
Shaliza Ibrahim
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Interfacial Area ◽  
Operating Conditions ◽  
Experimental Results ◽  
Dispersed Phase ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients ◽  
Wide Range

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.

scholarly journals KOEFISIEN PERPINDAHAN MASSA VOLUMETRIS KESELURUHAN PADA EKSTRAKSI Cu DARI LARUTAN CuSO4.5H2O DENGAN TRIRUTYL PHOSPHATE-KEROSIN DALAM DOUBLE-STAGE MIXER-SETTLER

2018 ◽  
Vol 7 (1) ◽  
pp. 731
Author(s):  
Panut Mulyono
Keyword(s):  
Aqueous Solution ◽  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Tributyl Phosphate ◽  
Continuous Phase ◽  
Hole Diameter ◽  
Extraction Column ◽  
Dispersed Phase ◽  
Dilute Aqueous Solution

Copper has been extracted by trtbuthyl phosphate-kerosene from a dilute aqueous solution with a double- stage mixer-settler extraction column. The extraction column used in this experiment was made of glass. The mixer diameter was equal to the diameter of settler was 13 cm. Both the mixer and settler heights were 8 cm. Drop coalescer was mounted in the middle of mixer and settler separator. The diameter of drop coalescer was 6 cm with the thickness of 1 cm. The hole diameter of drop coalescer was 1 mm The stirrer used in this experiment was cross flat blade with the diameter and width of the impeller was 6 cm and 8 mm, respectively. The overall volumetric coefficient of mass transfer (Kca) increased by increasing the flowrate of the continuous phase (Lc) at the constants stirring speed (N) and flowrate of the dispersed phase (Ld). The increase of Lc from 4.1634 cm3/second to 17.9436 cm3/second increased the Kca value from 6.6387x10-5/second to 23.1561x10-5/second or 248.8% The value of Kca was also increase by increasing N at the constant values of Lc and Ld Thie increase of N from 3.3333 rps to 8.3333 rps increased the Kca value from 6.0288x10-5/second to 6.6387x10-5/second or 10.1%.Keywords: Mass Transfer Coefficient, Extraction, Copper, Double-Stage Mixer-SettlerAbstrak Penelitian ini mempelajari perpindahan massa antar fasa pada ekstraksi Cu dart larutan CuSO4.5H2O dengan menggunakan pelarut tributyl phosphate dalam kerosin yang dilakukan dalam kolom ekstraksi double-stage mixer-settler yang dtsusun vertikal. Kolom ekstraksi mixer-settler dibuat darti gelas dengan diameter mixer sama dengan diameter sealer, yaitu 13 cm. Tinggi mixer juga sama dengan tinggt settler, yaitu 8 cm. Diameter drop coalescer 8 cm, tebal 1 cm, dan diameter lubangnya 1 mm. Pengaduk yang digunakan berbentuk flat blade dengan diameter 6 cm dan lebar blade 8 mm. Koeftsien perpindahan massa volumetris keseluruhan (Kca) naik dengan naiknya kecepatan alir fasa kontinyu (Lc) pada kecepatan putaran pengaduk (N) dan kecepatan alir fasa dispersi (Ld) tetap. Kenatkan nilai Lc dart 4,1634 cm3/detik menjadi 17,9436 cm3/detik meningkatkan nilai Kca dart 6,6387x10-5/detik menjadi 23,1561x10-5/detik atau 248,8% Kca juga naik dengan naiknya N pada Lc dan Ld yang tetap. Kenaikan nilai N dart 3,3333 rps menjadi 8,3333 rps meningkatkan nilai Kca dart 6,0288x10-5/detik menjadt 6,6387x10-5/detik atau 10,1%.Kata Kunci : Koefesien Perpindahan Massa, Ekstraksi, Tembaga, Double-Stage Mixer-Settler

scholarly journals Gas-liquid mass transfer with instantaneous chemical reaction in a slurry bubble column containing fine reactant particles

2016 ◽  
Vol 22 (1) ◽  
pp. 85-93 ◽  
Author(s):  
Xiaolei Li ◽  
Chunying Zhu
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Chemical Reaction ◽  
Bubble Column ◽  
Transfer Model ◽  
Phase System ◽  
Mass Transfer Model ◽  
Slurry Bubble Column ◽  
Irreversible Chemical Reaction

In this study, the mass transfer accompanied by an instantaneous irreversible chemical reaction in a slurry bubble column containing sparingly soluble fine reactant particles has been analyzed theoretically. Based on the penetration theory, combining the cell model, a one-dimensional mass transfer model was developed. In the model, the effects of the particle size and the particle dissolution near the gas-liquid interface on the mass transfer were taken into account. The mass transfer model was solved and an analytical expression of the time-mean mass transfer coefficient was attained. The reactive absorption of SO2from gas mixtures into Mg(OH)2/water slurry was investigated experimentally in a bubble column reactor to validate the mass transfer model. The results indicate that the present model has good predicting performance and could be used to predict mass transfer coefficient for the complicated gas-liquid-solid three-phase system with an instantaneous irreversible chemical reaction.

Experimental Investigation of the Effects of Surfactants on the Mass Transfer in Liquid-Liquid Extraction Equipments

2007 ◽  
Author(s):  
A. Haghdoost ◽  
M. Shah-Alami ◽  
H. Mansouri
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Terminal Velocity ◽  
Liquid Extraction ◽  
Drop Diameter ◽  
Transfer Resistance ◽  
Transfer Rates ◽  
Liquid Liquid Extraction ◽  
Triton X

Mass transfer rates to the drops in liquid-liquid extraction equipment are often likely to be reduced by the presence of surface active contaminants. This reduction in mass transfer is said to be due to a reduction in terminal velocity, and to changes in pattern of internal circulation. A single-drop extraction apparatus was used to investigate the dependency of mass transfer coefficient on the amount of surfactant added in a system of n-butanol/succinic acid/water. Three types of surfactants, SDS, DTMAC and Triton X-100, were used to study their effects on the inhibition of mass transfer in liquid-liquid extraction. The effect of surfactants concentration on extraction percentage, overall mass transfer coefficient, and extra mass transfer resistance was investigated for these surfactants. Also variation of terminal velocity as a function of surfactant concentration and drop diameter were illustrated for both surfactants. Finally these surfactants were compared to each other.

scholarly journals Influence of fluid-mechanical characteristics of the system on the volumetric mass transfer coefficient and gas dispersion in three-phase system

2014 ◽  
Vol 68 (4) ◽  
pp. 483-490
Author(s):  
Milena Knezevic ◽  
Dragan Povrenovic
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Solid Particles ◽  
Phase System ◽  
Volumetric Mass Transfer Coefficient ◽  
Gas Dispersion ◽  
Operation Conditions ◽  
Three Phase ◽  
Different Types

Distribution of gas bubbles and volumetric mass transfer coefficient, Kla, in a three phase system, with different types of solid particles at different operation conditions were studied in this paper. The ranges of superficial gas and liquid velocities used in this study were 0,03-0,09 m/s and 0-0,1 m/s, respectively. The three different types of solid particles were used as a bed in the column (glass dp=3 mm, dp=6 mm; ceramic dp=6 mm). The experiments were carried out in a 2D plexiglas column, 278 x 20,4 x 500 mm and in a cylindrical plexiglas column, with a diameter of 64 mm and a hight of 2000 mm. The Kla coefficient increased with gas and liquid velocities. Results showed that the volumetric mass transfer coefficient has a higher values in three phase system, with solid particles, compared with two phase system. The particles properties (diameter and density) have a major impact on oxygen mass transfer in three phase systems.

Influence of the fetch parameter on results from empirical correlations for estimating odorous emissions at passive liquid surfaces

2016 ◽  
Vol 74 (10) ◽  
pp. 2384-2391 ◽  
Author(s):  
Ademir A. Prata ◽  
Milena J. Calvo ◽  
Gaetano Boncardo ◽  
Eric C. Sivret ◽  
Jane M. Santos ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Model Compound ◽  
Emission Rate ◽  
Wastewater Treatment Plants ◽  
Effective Diameter ◽  
Empirical Correlations ◽  
Film Mass Transfer ◽  
Liquid Surfaces

Passive liquid surfaces in wastewater treatment plants may be potential sources of odorous emissions. This study investigates the occurrence and significance of deviations that may originate from the use of the effective diameter as fetch parameter in the empirical correlations utilised by the WATER9 model to estimate odorous emissions at passive liquid surfaces. A sensitivity analysis was performed using benzene as a model compound and considering representative conditions of wind speed and wind alignment. The gas-film mass transfer coefficient (kG) was found relatively in sensitive to the choice of the fetch parameter, deviating less than 15% for aspect rations up to 15. The calculation of the liquid-film mass transfer coefficient (kL) was much more sensitive (positive extreme of 126.98% and negative extreme of −54.80%), partially because of the use of different equations for different fetch-to-depth ratios. For more volatile compounds, such as benzene, these discrepancies will be significantly manifested in the estimated emission rate. When appropriate, the use of the actual fetch instead of the effective diameter is recommended.

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