scholarly journals Extraction of heavy metals from aqueous solutions in a modified rotating disc extractor

2016 ◽  
Vol 7 (2) ◽  
pp. 187-196
Author(s):  
B. A. Amer ◽  
M. H. Abdel-Aziz ◽  
E.-S. Z. El-Ashtoukhy ◽  
N. K. Amin
Keyword(s):  
Aqueous Solutions ◽  
Flow Rate ◽  
Rotational Speed ◽  
Cation Exchanger ◽  
Naphthenic Acid ◽  
Continuous Phase ◽  
Dispersed Phase ◽  
Mass Transfer Equation ◽  
Rotating Disc ◽  
Rate Of Extraction

Extraction of Cu+2 from dilute aqueous solutions as a case study by liquid cation exchanger in a modified rotating disc extractor was studied. The liquid cation exchanger consisted of naphthenic acid dissolved in an inert carrier kerosene. Variables studied were: initial concentration of Cu+2, disc rotational speed, concentration of naphthenic acid, flow rates of continuous and dispersed phase, degree of roughness, and number of rotating discs. The rate of extraction increased with increasing rotational speed, concentration of naphthenic acid, flow rate of dispersed phase, degree of roughness and number of discs to a certain number, while increasing Cu+2 concentration and flow rate of continuous phase decreased the rate of extraction. All variables were correlated by the dimensionless mass transfer equation. Possible practical applications of the present data in treating aqueous waste from different sources such as petrochemical industries, electroplating, and hydrometallurgical processes was highlighted.

scholarly journals Formation of Microdroplet in T-junction Microfluidic System: Experiment and Simulation

2018 ◽  
Vol 28 (3) ◽  
pp. 225
Author(s):  
Nguyen Thi Thai ◽  
Chu Thi Xuan ◽  
Pham Duc Thanh ◽  
Mai Anh Tuan ◽  
Nguyen Phuong Nhung
Keyword(s):  
Flow Rate ◽  
Experimental Methods ◽  
Continuous Phase ◽  
Microfluidic System ◽  
Dispersed Phase ◽  
Immiscible Liquids ◽  
Lateral Channel ◽  
System Experiment ◽  
System Geometry ◽  
Lithography Technique

The purpose of this study is to investigate the formation of the water droplet in oil using T-junction microfluidic device. Both numerical and experimental methods have been developed to explore the dependence of droplet size on the flow rate of two immiscible liquids as well as the system geometry. The velocity of droplet in channel is also considered. The microfluidic system was fabricated with lithography technique. The 3D simulation was performed based on COMSOL software using level set method. The size of droplet is inversely proportional to the flow rate of continuous phase according to exponential function, increases linearly with the flow rate of dispersed phase, and decreases as the width of lateral channel decreases.  While the decreasing of the width of the lateral channel gives rise to the increasing of droplet velocity, the velocity of droplet depends linearly on the flow rate of disperse phase. A good consistence was observed between the theory and the experiment.

scholarly journals Dinamika tetes ekstraksi cair-cair sistem air-metil etil keton (mek)-heksan dalam kolom isian

2018 ◽  
Vol 9 (3) ◽  
pp. 99
Author(s):  
Agus Mirwan ◽  
Danu Ariono
Keyword(s):  
Mass Transfer ◽  
Flow Rate ◽  
Transfer Process ◽  
Mass Transfer Process ◽  
Continuous Phase ◽  
Column Height ◽  
Dispersed Phase ◽  
Drop Diameter ◽  
Raschig Ring ◽  
Drop Dynamics

Mass transfer process occurs as effect of contact between continuous phase from above and dispersed phase from underside column. With existence of size and type of packing in column, that caused interfacial area to become bigger and residence time more and older so that improvement of mass transfer process. The aim of this research is to observe drop dynamics or movement behavior of drop in which the drop diameter size grouped based on current regime deputizing with Reynolds Number (Re) and to study mass transfer liquid-liquid extraction in packed column based on drop diameter size influenced by flow rate and packing type. Observation of drop behavior is done by using length square column transparent so that visually drop dynamics can be observed and recorded at every segment of column height using digital camera. This research will be done by varying packing type and flow rate of the dispersed phase and continuous phase to know behavior of drop. The research will be done by using water–MEK (methyl ethyl ketone)–n-hexane system. The result of this research for packing type of sphere and raschig ring show that more and more big dispersed phase flow rate and height from under side column (distributor), hence drop is more and more small with number of which more and more many. This caused significant increase on overall mass transfer coefficient.Keywords: drop distribution, sphere, raschig ring, drop diameter Abstrak Proses perpindahan massa ekstraksi cair-cair dalam kolom isian terjadi akibat adanya kontak antara fase kontinu dan fase dispersi yang dialirkan secara berlawanan. Berbagai macam ukuran dan jenis isian yang digunakan dalam kolom, menyebabkan luas permukaan kontak menjadi lebih besar dan waktu kontak makin lama sehingga terjadi peningkatan proses perpindahan massa. Penelitian ini bertujuan mengamati dinamika pergerakan tetesan dengan cara mengelompokkan ukuran diameter tetesan berdasarkan pada rezim aliran yang diwakilkan dengan Bilangan Reynold (Re) dan mempelajari perpindahan massa pada ekstrasi cair-cair dalam kolom isian yang didasarkan ukuran diameter tetesan yang dipengaruhi laju alir dan jenis isian. Pengamatan perilaku tetesan dilakukan dengan menggunakan kolom persegi panjang yang transparan sehingga secara visual dinamikanya dapat diamati dan direkam pada tiap segmen ketinggian kolom menggunakan kamera digital. Percobaan dilakukan dengan menggunakan sistem air-MEK (metil etil keton)-n-heksan. Hasil penelitian untuk jenis isian bola padat dan raschig ring menunjukkan bahwa makin besar laju alir fase dispersi dan ketinggian dari bagian bawah (distributor), maka tetesannya makin kecil dengan jumlah yang makin banyak. Hal ini menyebabkan kenaikan yang signifikan terhadap koefisien perpindahan massa keseluruhan.Kata kunci: distribusi tetesan, bola, raschig ring, diameter tetesan.

scholarly journals Droplet Formation in a Cross-Junction Microfluidic Channel with Non-Newtonian Dispersed Phase

2021 ◽  
Vol 4 (1) ◽  
pp. 21
Author(s):  
Maryam Fatehifar ◽  
Alistair Revell ◽  
Masoud Jabbari
Keyword(s):  
Power Law ◽  
Flow Rate ◽  
Xanthan Gum ◽  
Real Life ◽  
Microfluidic Channel ◽  
Shear Thinning ◽  
Continuous Phase ◽  
Droplet Generation ◽  
Dispersed Phase ◽  
Generating Series

Microfluidics enables generating series of isolated droplets for high-throughput screening. As many biological/chemical solutions are of shear thinning non-Newtonian nature, we studied non-Newtonian droplet generation to improve the reliability of simulation results in real-life assays. We considered non-Newtonian power-law behaviour for Xanthan gum aqueous solution as the dispersed phase, and Newtonian canola oil as the continuous phase. Simulations were performed in OpenFOAM, using the inter foam solver and volume of fluid (VOF) method. A cross-junction geometry with each inlet and outlet channel height (H) and width (W) equal to 50 micrometers with slight contractions in the conjunctions was used to gain a better monodispersity. Following validation of the numerical setup, we conducted a series of tests to provide novel insight into this configuration. With a capillary number, of 0.01, dispersed phase to continuous phase flow-rate ratio of 0.05, and contact angle of 160°, simulations revealed that, by increasing the Xanthan gum concentration (0, 800, 1500, 2500 ppm) or, in other words, decreasing the n-flow behaviour index from 1 to 0.491, 0.389, and 0.302 in power-law model, (a) breakup of the dispersed phase thread occurred at 0.0365, 0.0430, 0.0440, and 0.0450 s; (b) the dimensionless width of the thread at the main channel entrance increased from 0 to 0.066, 0.096, and 0.16; and (c) the dimensionless droplet diameter decreased from 0.76 to 0.72, 0.68, and 0.67, respectively. Our next plan is to study effect of shear-thinning behaviour on droplet generation in different Ca and flow-rate ratios.

scholarly journals A Newly Developed Empirical Predictive Model for the Dispersed Phase (DP) Holdup in Rotating Disc Contactors

2021 ◽  
Vol 5 (4) ◽  
pp. 79
Author(s):  
Ayham M. I. Al-Rahawi ◽  
Wallaa A. Noori ◽  
Amer A. Abdulrahman ◽  
Hasan Sh. Majdi ◽  
Issam K. Salih ◽  
...  
Keyword(s):  
Physical Properties ◽  
Flow Rate ◽  
Production Capacity ◽  
Hole Diameter ◽  
Operating Conditions ◽  
Percentage Error ◽  
Extraction Column ◽  
Dispersed Phase ◽  
Rotating Disc ◽  
Average Percentage

Newly novel developed correlations were derived to predict the dispersed phase (DP) holdup in a rotating disc contactor (RDC) extraction column. DP holdup is one of the significant parameters in the design of liquid–liquid contactors and for calculating their production capacity. Despite the availability of quite a large number of holdup prediction correlations for the RDC, most of these correlations are either general in nature or valid for a limited range of operating conditions. This study conducted an experimental and theoretical investigation of the RDC holdup under the influence of varying geometries, including variations in the dispersed phase distributor, speed of the disc, flow rate, and physical characteristics of the system. The analysis revealed that the holdup decreased with an increasing distributor hole diameter and increased with an increasing disc speed and total flow rate. The effect of the physical properties on the holdup was larger than the effect of the disc speed. Using the measurements of over 150 runs, two RDC column holdup predictive models were proposed and evaluated. The first correlation was derived in terms of the distributor hole diameter, operating parameters, system physical properties, and column geometry. The second correlation excluded the column geometry. These correlations, which consider the distributor hole inlet diameter in predicting the DP holdup for an RDC column, were presented for the first time in this study. The predictive capability of these correlations was evaluated via their standard deviation (SD) and mean average percentage error (MAPE). The respective SD and MAPE of the two correlations were 1.7 and 5.2% for the first correlation and 1.6 and 11.4% for the second.

scholarly journals Experimental Studies of Droplet Formation Process and Length for Liquid–Liquid Two-Phase Flows in a Microchannel

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1341
Author(s):  
Li Lei ◽  
Yuting Zhao ◽  
Wukai Chen ◽  
Huiling Li ◽  
Xinyu Wang ◽  
...  
Keyword(s):  
Formation Mechanism ◽  
Flow Rate ◽  
Volume Flow Rate ◽  
Scaling Law ◽  
Experimental Studies ◽  
Droplet Formation ◽  
Continuous Phase ◽  
Volume Flow ◽  
Dispersed Phase ◽  
Two Phase

In this study, changes in the droplet formation mechanism and the law of droplet length in a two-phase liquid–liquid system in 400 × 400 μm standard T-junction microchannels were experimentally studied using a high-speed camera. The study investigated the effects of various dispersed phase viscosities, various continuous phase viscosities, and two-phase flow parameters on droplet length. Two basic flow patterns were observed: slug flow dominated by the squeezing mechanism, and droplet flow dominated by the shear mechanism. The dispersed phase viscosity had almost no effect on droplet length. However, the droplet length decreased with increasing continuous phase viscosity, increasing volume flow rate in the continuous phase, and the continuous-phase capillary number Cac. Droplet length also increased with increasing volume flow rate in the dispersed phase and with the volume flow rate ratio. Based on the droplet formation mechanism, a scaling law governing slug and droplet length was proposed and achieved a good fit with experimental data.

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.

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.

Computational Investigation of Microdroplet Formation in a Crossflow Membrane Emulsification Process

2011 ◽  
Author(s):  
Manabendra Pathak
Keyword(s):  
Surface Tension ◽  
Flow Rate ◽  
Viscosity Ratio ◽  
Period Doubling ◽  
Continuous Phase ◽  
Inertia Force ◽  
Dispersed Phase ◽  
Phase Flow ◽  
Membrane Emulsification ◽  
Emulsification Process

Monodisperse microdroplets are formed, when a liquid is injected through a micropore into another immiscible liquid. Depending on the relative flow between the two phases, droplets may form in quiescent, coflowing and crossflowing environment. The dispersions of one phase liquid in another crossflowing liquid are observed in liquid emulsification process and the system has been used extensively in microfluidic devices to produce monodisperse microdroplets with controllable size. Liquid emulsions are widely used in food, cosmetics, pharmaceutics and polymer industries. In the present work, microdroplet formation in a crossflow membrane emulsification process has been investigated computationally using VOF/finite volume method. The full transient simulation has been carried out starting from the injection of dispersed phase to breakup into drops for different values of dispersed phase and continuous phase flow rate, surface tension and viscosity ratio of both the phases. Depending upon the values of the both phases, the droplet formation process shows the dripping and jetting behavior. The qualitative features of the two regimes and their transition have been correlated with different non-dimensional numbers such as Capillary number, Weber number and viscosity ratio of the two phase liquids. Some interesting nonlinear behavior such as period doubling been observed near the transition between the dripping and jetting regimes has. The topological characteristics of dripping, jetting and transition regimes in membrane emulsification have been observed different than in the cases of T-junction emulsification and flow focusing emulsification. Two ways of dripping to jetting transition have been observed, one with the increasing dispersed phase flow rate at constant continuous phase flow rate and other way is reducing the surface tension at constant dispersed phase flow rate. The effect of inertia force has been observed negligible for high value of surface tension and significant for lower surface tension value.

Absorption of oxygen into solutions of polymers

1986 ◽  
Vol 51 (10) ◽  
pp. 2127-2134 ◽  
Author(s):  
František Potůček ◽  
Jiří Stejskal
Keyword(s):  
Mass Transfer ◽  
Aqueous Solutions ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Flow Rate ◽  
Liquid Flow ◽  
Flow Curve ◽  
Liquid Flow Rate ◽  
Polymer Concentration ◽  
Newtonian Liquids

Absorption of oxygen into water and aqueous solutions of poly(acrylamides) was studied in an absorber with a wetted sphere. The effects of changes in the liquid flow rate and the polymer concentration on the liquid side mass transfer coefficient were examined. The results are expressed by correlations between dimensionless criteria modified for non-Newtonian liquids whose flow curve can be described by the Ostwald-de Waele model.

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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