Experimental Investigation of Phase Inversion of Liquid-Liquid Systems in a Spray Extraction Column

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An experimental study of the phase inversion behavior of liquid-liquid dispersion has been conducted in a spray extraction column for systems of toluene / water, n-hexane/water, CCl4/water, toluene /water + glycerol (25 % wt), toluene + CCl4 (25 % wt) / water and toluene / acetic acid (5 % wt)/water. The effects of physical properties, mass transfer and column geometry on phase inversion have been investigated. The results show that the dispersed phase hold up sufficient for phase inversion increases in o/w dispersion and decreases in w/o dispersion by increasing interfacial tension. Also, it was found that by increasing the viscosity of aqueous phase, dispersed phase hold up decreases at phase inversion point in both o/w and w/o dispersions. The tendency to phase inversion increases in o/w dispersion with an increase in density difference of two phases. It was observed that dispersed phase hold up at phase inversion point decreases in the presence of mass transfer, when the direction of mass transfer is from dispersed phase to continuous phase. The results show that dispersed phase holdup increases with drop size at phase inversion point and column diameter has an important effect on phase inversion because of wall effect.