scholarly journals Hydrodynamics of a pilot plant spray extraction column

2018 ◽  
pp. 159-168 ◽  
Author(s):  
Milan Sovilj ◽  
Branislava Nikolovski ◽  
Momcilo Spasojevic
Keyword(s):  
Pilot Plant ◽  
Droplet Diameter ◽  
Great Influence ◽  
Continuous Phase ◽  
Liquid System ◽  
Superficial Velocity ◽  
Hydrodynamic Characteristics ◽  
Extraction Column ◽  
Dispersed Phase ◽  
Axial Dispersion Coefficient

The hydrodynamic characteristics of the liquid-liquid system of toluene-water in a pilot plant spray extraction column were experimentally determined. The experimental data for hydrodynamic characteristics such as the dispersed phase holdup, mean droplet size, and the axial dispersion coefficient were obtained. The dispersed phase superficial velocity had a great influence on toluene holdup. At the same time, a strong effect of the continuous phase superficial velocity on the dispersed phase holdup was evident. The dispersed phase holdup had a tendency to increase when the ratio of the dispersed phase superficial velocity and characteristic velocity increased. The Sauter mean droplet diameter decreased with increasing dispersed phase superficial velocity when the continuous phase superficial velocity remained constant. In contrast, it was not affected by the changes in the continuous phase superficial velocity while the dispersed phase superficial velocity remained constant. It was concluded that the Peclet number increased as a result of an increase of the Reynolds number.

scholarly journals Hydrodynamics of pulsed sieve-plate extraction columns

2020 ◽  
Vol 74 (1) ◽  
pp. 1-14
Author(s):  
Milan Sovilj ◽  
Momcilo Spasojevic
Keyword(s):  
Continuous Phase ◽  
Liquid System ◽  
Axial Dispersion ◽  
Superficial Velocity ◽  
Dispersed Phase ◽  
Geometrical Parameters ◽  
Drop Diameter ◽  
Sieve Plate ◽  
Axial Dispersion Coefficient ◽  
Hydrodynamic Parameters

This paper presents a review of some hydrodynamic parameters in pulsed sieve-plate extraction columns. The hydrodynamic parameters in liquid-liquid systems in these columns were analyzed regarding the effects of operating and geometrical parameters. The values of Sauter mean drop diameter were function of the existing work flow regimes in the column device defined as mixer-settler, emulsion and dispersion regimes. It was concluded that the dispersed-phase holdup was a function of the mean drop diameter and dispersed-phase superficial velocity. An increase in the dispersed-phase holdup induced an increase in the interface area in the liquid-liquid system. Knowledge of the value of the dispersed-phase holdup can be used for calculation of the volumetric mass transfer coefficient, one of the important factor in the design of the column extractor. It was concluded that the increase in the dispersed-phase superficial velocity is causing a decrease in axial dispersion. On the other hand, an increase in the continuous-phase superficial velocity is causing the increase in the axial dispersion coefficient. Some of the empirical equations proposed in literature for calculations of the hydrodynamic parameters were presented. These correlations, derived for determination of the hydrodynamic parameters in pulsed sieve-plate extraction columns, can be used for the design of these liquid-liquid extraction columns.

Axial Dispersion in a Three-Phase Gas-Agitated Spray Extraction Column

1998 ◽  
Vol 63 (2) ◽  
pp. 283-292 ◽  
Author(s):  
Milan Sovilj
Keyword(s):  
Gas Phase ◽  
Dispersion Coefficient ◽  
Continuous Phase ◽  
Axial Dispersion ◽  
Superficial Velocity ◽  
Extraction Column ◽  
Dispersed Phase ◽  
Dispersion Coefficients ◽  
Axial Dispersion Coefficient ◽  
Three Phase

The continuous-phase axial dispersion coefficients of the three-phase gas-liquid-liquid system in a gas-agitated spray extraction column 10 cm i.d. at 20 °C were examined. The system used was water as continuous phase, toluene as dispersed phase, and air as gaseous phase. The rise in the gas phase superficial velocity increased the continuous-phase axial dispersion coefficient. A non-linear dependence between the continuous-phase axial dispersion coefficient and the continuous phase superficial velocity was observed. No correlation was found between the continuous-phase axial dispersion coefficient and dispersed phase superficial velocity. The increase in the gas phase hold-up corresponded to a slight increase in the continuous-phase axial dispersion coefficient. The increase in the dispersed phase hold-up generated a growth of the continuous-phase axial dispersion coefficient. A comparison was made of the continuous-phase axial dispersion coefficients of the three-phase (air-water-toluene) and two-phase (water-toluene) systems.

scholarly journals Holdup and characteristic velocity in a pulsed packed extraction column

2020 ◽  
Vol 9 (8) ◽  
pp. e674982543
Author(s):  
Jarlon Conceição da Costa ◽  
Luiz Mário Nelson de Góis ◽  
Silvana Mattedi e Silva
Keyword(s):  
Flow Rate ◽  
Water System ◽  
Continuous Phase ◽  
Liquid System ◽  
Operating Conditions ◽  
Extraction Column ◽  
Dispersed Phase ◽  
Internal Diameter ◽  
Phase Flow ◽  
Characteristic Velocity

The present work aims to evaluate the hydrodynamics of a pulsed packed extractor, with an internal diameter of 0.026m and a length of 1.0m, using the liquid butanol-water system. Thus, the basic parameters obtained for the hydrodynamic study of the extraction column in question as dispersed phase, slip velocity, characteristic velocity and flooding point. The methodology used in the work consisted of determining the holdup fraction of the dispersed phase, obtained through tests of simultaneous interruptions in the column feedings. The effects of frequency pulsation, dispersed phase flow rate and continuous phase flow rate investigated in the analysis of these parameters. New empirical correlations derived from the predictions of the parameters studied obtained in terms of operating variables and physical properties of the liquid system involved. The average absolute value of the relative error (AARE) was always below 5.6%. Good agreement between calculated and experimental results observed for all investigated operating conditions.

Effect of Geometry on Droplet Generation in a Microfluidic T-Junction

2013 ◽  
Author(s):  
Katerina Loizou ◽  
Wim Thielemans ◽  
Buddhika N. Hewakandamby
Keyword(s):  
Aspect Ratio ◽  
Cross Section ◽  
Droplet Formation ◽  
Continuous Phase ◽  
Main Channel ◽  
Superficial Velocity ◽  
Droplet Generation ◽  
Dispersed Phase ◽  
Aspect Ratios ◽  
The Cross

The main aim of this study is to examine how the droplet formation in microfluidic T-junctions is influenced by the cross-section and aspect ratio of the microchannels. Several studies focusing on droplet formation in microfluidic devices have investigated the effect of geometry on droplet generation in terms of the ratio between the width of the main channel and the width of the side arm of the T-junction. However, the contribution of the aspect ratio and thus that of the cross-section on the mechanism of break up has not been examined thoroughly with most of the existing work performed in the squeezing regime. Two different microchannel geometries of varying aspect ratios are employed in an attempt to quantify the effect of the ratio between the width of the main channel and the height of the channel on droplet formation. As both height and width of microchannels affect the area on which shear stress acts deforming the dispersed phase fluid thread up to the limit of detaching a droplet, it is postulated that geometry and specifically cross-section of the main channel contribute on the droplet break-up mechanisms and should not be neglected. The above hypothesis is examined in detail, comparing the volume of generated microdroplets at constant flowrate ratios and superficial velocities of continuous phase in two microchannel systems of two different aspect ratios operating at dripping regime. High-speed imaging has been utilised to visualise and measure droplets formed at different flowrates corresponding to constant superficial velocities. Comparing volumes of generated droplets in the two geometries of area ratio near 1.5, a significant increase in volume is reported for the larger aspect ratio utilised, at all superficial velocities tested. As both superficial velocity of continuous phase and flowrate ratio are fixed, superficial velocity of dispersed phase varies. However this variation is not considered to be large enough to justify the significant increase in the droplet volume. Therefore it can be concluded that droplet generation is influenced by the aspect ratio and thus the cross-section of the main channel and its effect should not be depreciated. The paper will present supporting evidence in detail and a comparison of the findings with the existing theories which are mainly focused on the squeezing regime.

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 Reactive Zinc Extraction in MRDC Column; Case Study by Mathematical Modelling and Applying the Droplet Size Distribution with Forward Mixing Approach

2021 ◽  
Author(s):  
Benyamin Shakib ◽  
Rezvan Torkaman ◽  
Meisam Torab-Mostaedi ◽  
Mojtaba Saremi ◽  
Mehdi Asadollahzadeh
Keyword(s):  
Mathematical Modeling ◽  
Mass Transfer ◽  
Solvent Extraction ◽  
Mass Transfer Rate ◽  
Continuous Phase ◽  
Axial Dispersion ◽  
Extraction Column ◽  
Dispersed Phase ◽  
Rotor Speed ◽  
Zinc Extraction

Abstract In this survey, the reactive mass transfer data are determined for zinc extraction from chloride solution using D2EHPA in the MRDC extraction column. The numerical analysis for evaluating the column performance is applied to describe mass balance equations. Four mathematical models (backflow, forward mixing, plug flow, and axial dispersion) are investigated to compute the mass transfer coefficients of the dispersed phase. The solvent extraction experiments showed that the optimum zinc transport efficiency in rotor speed of 410 rpm in this column is equal to 98.85% and 99.85 for extraction and stripping stages, respectively. The model's achievement is compared with the solvent extraction data and a significant validity is obtained by coupling the forward mixing approach. The mathematical modeling expresses that the coefficients of axial dispersion and backflow based on the continuous phase increase by an increase in the rotor speed and inlet continuous phase rate. While these coefficients reduce at a higher inlet dispersed phase rate. The FMM method is preferred to predict the reactive mass transfer rate in the MRDC column due to the lowest relative deviation. The experimental study and mathematical modeling in this report provide beneficial information about the metallurgical industry to design solvent extraction equipment.

scholarly journals Radiotracer investigations to study the hydrodynamic characteristics of continuous phase in a pulsed sieve plate extraction column

2013 ◽  
Vol 50 ◽  
pp. 01004
Author(s):  
G.U. Din ◽  
I.H. Khan ◽  
I.R. Chughtai ◽  
M.H. Inayat ◽  
J.H. Jin
Keyword(s):  
Continuous Phase ◽  
Hydrodynamic Characteristics ◽  
Extraction Column ◽  
Sieve Plate

Investigation on the Droplet Formation Time With Xanthan Gum Solutions at a T-Junction

2012 ◽  
Author(s):  
Zhipeng Gu ◽  
Jong-Leng Liow ◽  
Guofeng Zhu
Keyword(s):  
Flow Rate ◽  
Xanthan Gum ◽  
Critical Concentration ◽  
Droplet Diameter ◽  
Droplet Formation ◽  
Continuous Phase ◽  
Formation Time ◽  
Drop Formation ◽  
Dispersed Phase ◽  
Phase Flow

Xanthan gum solutions with various concentrations were used as the dispersed phase to study the formation time for drop formation at a T-junction. Two critical concentrations (0.05 and 0.2 wt%) of xanthan gum solutions were observed resulting in three distinct regimes. The droplet diameter increased with increasing xanthan gum concentration within each regime but the transition through each critical concentration was accompanied by a significant reduction in the droplet size. Experimental results showed that the droplet formation time decreased exponentially with increasing continuous phase flow rate. It was also found that the formation time was reduced with increasing dispersed phase flow rate. Xanthan gum solutions with a higher concentration within each regime resulted in a longer formation time, and there was a decrease in the formation time at each critical concentration. The formation time consists of growth and breakup stages and the effect of xanthan gum concentration on each stage was examined.

scholarly journals Hydrodynamics in spray and packed liquid-liquid extraction columns: A review

2019 ◽  
Vol 38 (2) ◽  
pp. 267
Author(s):  
Milan N. Sovilj ◽  
Branislava G. Nikolovski ◽  
Momčilo Đ. Spasojević
Keyword(s):  
Slip Velocity ◽  
Drop Size ◽  
Dispersion Coefficient ◽  
Packed Bed ◽  
Axial Dispersion ◽  
Hydrodynamic Characteristics ◽  
Dispersed Phase ◽  
Drop Diameter ◽  
Axial Dispersion Coefficient ◽  
Experimental Findings

This work provides a review of hydrodynamic characteristics such as the slip velocity, the dispersed-phase holdup, mean drop size, and axial dispersion of non-mechanically agitated liquid-liquid (L-L) extractors, with special reference to spray and packed bed columns. The complexity and importance of hydrodynamic behavior in designing and scaling up L-L extractors was a driving force to analyze, compare and discuss some important experimental findings available in the literature. The effects of phase velocities and the dispersed-phase holdup on the slip velocity, the mean drop size and the axial dispersion coefficient were studied and presented. Empirical correlations for slip velocity, the Sauter mean drop diameter and the axial dispersion coefficient, which were taken from the literature, were commented in terms of their applicability.

Phase Inversion in Two-Phase Liquid Systems

1992 ◽  
Vol 57 (7) ◽  
pp. 1419-1423
Author(s):  
Jindřich Weiss
Keyword(s):  
Interfacial Tension ◽  
Phase Inversion ◽  
Continuous Phase ◽  
Considerable Effect ◽  
Weak Dependence ◽  
Dispersed Phase ◽  
Two Phase ◽  
Liquid Systems ◽  
Phase Liquid

New data on critical holdups of dispersed phase were measured at which the phase inversion took place. The systems studied differed in the ratio of phase viscosities and interfacial tension. A weak dependence was found of critical holdups on the impeller revolutions and on the material contactor; on the contrary, a considerable effect of viscosity was found out as far as the viscosity of continuous phase exceeded that of dispersed phase.

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