Prediction of drop size in a pulsed and non-pulsed disc and doughnut solvent extraction column

Chemical Engineering Science

Smith

et al. 2017

Self Cite

Mechanical agitation or pulsation is usually introduced to a solvent extraction column to improve the efficiency. Recently a number of industrial scale pulsed disc and doughnut (PDD) solvent extraction columns have been found to have higher extraction efficiency while running with non-pulsing. In this study, the mass transfer performance of a PDD column was measured under pulsing and non-pulsing conditions using a 72.5 mm diameter disc and doughnut column. The effects of pulsation intensity and dispersed and continuous phase velocity on the mass transfer performance have been investigated. The results show that, under non-pulsing conditions, the overall mass transfer coefficient increased with increasing continuous phase flow rate and slightly decreased with increasing dispersed phase flow rate. With increasing pulsation intensity, the overall mass transfer coefficient decreased at first and then increased. Two correlations are proposed to predict the height of mass transfer unit and overall mass transfer coefficient in a PDD column including pulsing and non-pulsing conditions.

Section: Introductionmentioning

confidence: 99%

Mass transfer in a pulsed and non-pulsed disc and doughnut (PDD) solvent extraction column

Chemical Engineering Science

Smith

et al. 2017

Self Cite

“…Wang et al [3] developed an empirical correlation based on 244 droplet size experimental data points from operation of a pulsed disc and doughnut extraction column using seven different liquid-liquid systems and pulsation rates which varied from 0 to 0.04 m/s.…”

Section: Drop Sizementioning

confidence: 99%

“…Most correlations in the literature are not suitable for the prediction of Sauter mean diameter under no pulsing conditions, with the exception of the equations presented by Van Delden et al [10,11] and Wang et al [3] . Moreover, the correlation developed by Van Delden (refer to equation 16) was modified to fit the experimental data from this study via refitted constants shown in Table 5.…”

Section: Prediction Of Sauter Mean Diameter and Cumulative Volume Dismentioning

confidence: 99%

“…The efficiency of industrial solvent extraction columns can be successfully enhanced with the introduction of internals such as the Tenova standard disc and doughnuts which are especially useful when the liquid-liquid system is not limited by kinetics. Tenova standard disc and doughnut internals [2][3][4] have been used in solvent extraction columns for applications in the chemical industry and minerals processing (e.g. uranium, nickel, cobalt, zinc and titanium).…”

mentioning

confidence: 99%

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Comparison of the Hydrodynamic Performance of Pulsed Solvent Extraction Columns with Tenova Pulsed Column Kinetics Internals and Standard Disc and Doughnut Internals for Copper Extraction Using the LIX 84 System

Solvent Extraction and Ion Exchange

Mumford

et al. 2017

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The dispersed phase holdup and droplet size are important parameters for understanding the hydrodynamic performance of pulsed solvent extraction columns. This study provides a comparison of the hydrodynamic performance between a Tenova Pulsed Column with Kinetics Internals (TPC-KI) and a pulsed column with standard disc and doughnut internals. The TPC-KI internals are designed to improve the performance of systems with slow reaction kinetics, such as copper extraction with LIX 84 which was the focus of the current study. Holdup and drop size have been measured as a function of pulsation intensity and phase velocities for both types of column internals. Lower holdup and larger drop sizes were obtained with the TPC-KI internals which indicates a higher flood point and a higher throughput. Correlations have been developed to predict the performance of these internals over a range of operating conditions.

“…To date, very little experimental data is available on the actual column performance in this operating regime. The dispersed phase holdup and drop size in a PDD column under no pulsation and low pulsation conditions have been studied in our previous research 13,14 . The aim of work is to explore the effect of axial dispersion on the performance of the PDD column under low to to zero pulsation operating conditions.…”

Section: Introductionmentioning

confidence: 99%

Axial Dispersion in a Pulsed and Nonpulsed Disc and Doughnut Solvent Extraction Column

Smith

et al. 2017

Ind. Eng. Chem. Res.

Self Cite

In solvent extraction columns mechanical agitation is usually introduced to improve the extraction efficiency. However some industrial columns have been found to have higher extraction efficiency while running with no pulsation. In this study, axial dispersion coefficients in the continuous phase were measured under pulsing and non-pulsing conditions using a 72.5 mm diameter disc and doughnut solvent extraction column. The axial dispersion coefficients were measured using the unsteady tracer injection method. Under non-pulsing conditions, the axial dispersion coefficient increased with increasing continuous phase velocity, but it did not change significantly with the increase of dispersed phase velocity. With increasing pulsation intensity, the axial dispersion coefficient increased. A correlation is proposed to predict the continuous phase axial dispersion coefficient in a pulsing and non-pulsing disc and doughnut solvent extraction column.