Mass transfer investigation in a horizontal–vertical pulsed packed extraction column

Abstract

In this study, hydrodynamic parameters and the mass transfer coefficient were investigated in a pilot version of a horizontal-vertical pulsed packed extraction column using a toluene-acetone-water system. The effects of the operational parameters on the volumetric overall mass transfer coefficient and hydrodynamic parameters away from the flooding point were studied, and it was found that the volumetric overall mass transfer coefficient, mean drop size and disperse phase holdup were significantly affected by the pulse intensity. However, the dispersed and continuous phase flow rates have a weaker effect. On the other hand, by increasing the pulse intensity the mean drop size and volumetric overall mass transfer coefficient were reduced and increased, respectively, in both sections of the column, but the disperse phase holdup displayed different behavior in the horizontal and vertical sections. By increasing the pulse intensity, the disperse phase holdup was first reduced and then increased in the horizontal section; however, an incremental trend was observed in the vertical section. The effect of the dispersed phase flow rate was significant for all the investigated parameters, but weaker. For instance, all the investigated parameters were increased by enhancing the dispersed phase flow rate. In contrast, the continuous phase flow rate has sometimes had no significant effect, for example, on the mean drop size in both sections of the column. Finally, two empirical correlations for the prediction of the volumetric overall mass transfer coefficient based on the continuous phase were derived in terms of the Sherwood number, Reynolds number and other dimensionless numbers. Good agreement between predictions and experiments was found for all operating conditions that were investigated.

Experimental investigation, modelling, and order of magnitude analysis of oxygen mass transfer in pulsed plate column with α‐Fe2O3 nanofluid

“…The dispersion regime is characterized by a non‐uniform bubble size distribution and no bubble coalescence occurs. [ 99 ] At higher pulsing velocities, good mixing occurs and the external energy dissipation is even throughout the column. [ 7,104 ] The pulsing velocities in the dispersion regime prevent the accumulation of bubbles either above or below each perforated plate as turbulence stresses dominate over the bubble coalescence tendency.…”

“…Many researchers have reported through experimental findings that the mass transfer performance enhances with an increase in the pulsing velocity. [49,[98][99][100] It is found that as the pulsing velocity increases, the degree of turbulence effect transmitted in the column is more. The mean bubble diameter is affected by the pulsing velocity, as the additional rigorous shear forces that are created by the increased pulsing velocity cause the collapse of the bigger bubble into smaller ones, hence increasing the interfacial area which increases k L a.…”

Mean drop behavior in the standard liquid–liquid extraction systems on an L-shaped pulsed sieve-plate column: experiment and modeling

“…Solvent extraction is a technique for separation having broad applications in different industries such as the petroleum, metal salt extraction, wastewater purification, pharmaceutical, and nuclear industries. 1–11 Various types of liquid–liquid contactors have been developed, including columns, centrifugal extractors, and mixer-settlers in this respect over many years. 12–19 The contactors with internal moving parts have a lower capacity than convectional non-internal moving part contactors, though their extraction efficiency is high.…”

“…12–19 The contactors with internal moving parts have a lower capacity than convectional non-internal moving part contactors, though their extraction efficiency is high. 1,2 Hence, efforts have been made to expand the extractive columns lacking mixers or internal moving parts. Generally, criteria to choose a suitable contractor must be considered, including capacity, maintenance, protection, high efficiency under a broad range of operational conditions, process control, and cost.…”

“…The L-shaped (horizontal–vertical) pulsed sieve-plate column (LPSPC) is a novel extractor of pulsed column. 1,12 It is expected that this class of columns will present more advantages and will perform better than compared to those with the horizontal or vertical extraction columns in the applications with region limitation. 23–28 In addition, its installation height and required surface area are less than those of vertical and horizontal columns.…”