Drop size in a liquid pulsed sieve-plate extraction column

Abstract

-The (Benzoic acid + kerosene + water) system was studied in a 5.0 cm diameter liquid pulsed liquid-liquid extraction column with a total number of 80 sieve plates. The effect of pulsation intensity, dispersed phase superficial velocity, and continuous phase superficial velocity on volume-surface mean diameter was studied. Generally, the mean drop diameter decreased more rapidly with the increase of pulsation intensities and superficial velocities at low pulsation intensities and superficial velocities. However, the effect was not found to be significant at higher pulsation intensities and higher superficial velocities. In the interpretation of the experimental results, the drop size was observed to be a function of the operating regimes (mixer-settler, dispersion, and emulsion) of the pulsed sieve-plate extraction column. The experimental mean drop diameters were compared to the most acceptable analytical drop size correlation developed by Kumar and Hartland (1986). The correlation proved to be in good agreement for the column operating in the dispersion regime.

Mass transfer efficiency of a tall and low plate free area liquid pulsed sieve-plate extraction column

“…It is, therefore, concluded that as the diameter of the dispersed phase drop decreases more rapidly than the holdup and contributes more towards mass transfer, the overall effect is the increase in mass transfer efficiency [17]. In support of that, it is important to mention here that unlike dispersed phase holdup, the average drop size of the dispersed phase always decreases with an increase in pulsation intensity [26,[40][41][42][43][44]. Further, it may be deduced from Fig.…”

“…Assuming plug flow of the phases (negligible axial diffusivities in the phases) and considering both equilibrium and operating lines to be straight (dilute solutions), overall number of transfer units may be defined as apparent number of transfer units as given by the following expression [9,25]:…”

“…The overall apparent mass transfer coefficient based on continuous phase was calculated using the following equation [25,36]:…”

“…This suggests that with an increase in pulsation intensity, initially height of transfer unit decreases more rapidly and then decreases at a relatively lower rate. Cohen and Beyer [1] for boric acidwater-isoamyl alcohol system, Smoot and Babb [9] for both acetone-water-1,1,2-trichloroethane system and acetic acid-water-methyl isobutyl ketone (MIBK) system, Gourdon and Casamatta [15] for acetone-water-toluene system, Venkatanarasaiah and Varma [17] for both n-butyric acid-kerosene-water system and benzoic acid-waterkerosene system, Li et al [22] for nitric acid-30% TBP (in kerosene)-water system, He et al [23] for caprolactamwater-benzene system, Jahya et al [24] for acetone-watertoluene system, Usman et al [25] for acetic acid-waterethyl acetate system, and Torab-Mostaedi et al [27] for both acetone-water-toluene system and acetone-waterbutylacetate system have observed a continuous and generally a similar increase in mass transfer performance with an increase in pulsation intensity. The height of transfer unit and, therefore, mass transfer performance may depend on drop size and dispersed phase holdup.…”

“…A schematic diagram of the column is given in Fig. 1 while additional detail of the experimental apparatus is given in Usman et al [25]. Acetic acid-kerosene-water and propionic acid-kerosene-water systems were used to study the performance of the column.…”