The Math Correlation of Material Chemistry and Physical Factors on Phase Inversion in the Separation of Aqueous and Organic Phases in an Agitated Vessel

Phase inversion phenomenon is important in design of liquid-liquid extraction systems. In this study, the effects of the impeller speed, the hold up of dispersed phase, and surface active agent concentration on phase inversion phenomenon for toluene-water and butanol-water with sodium dodecyl sulfate (SDS) as surface active agent, were investigated. Based on the experiments in this work, some models are developed for the impeller speeds when the phase inversion phenomenon has been occurred (N-PI). Comparison between models for toluene-water and butanol-water systems with paddle and propeller blades, with and without SDS has been done. The dispersed to continuous phase ratios (volumetric ratio of toluene to water) were divided into three regions V-T/V-W < 0.5, 0.5 < V-T/V-W < 1, and V-T/V-W > 1. It was found that by increasing the impeller speed and also the ratio of dispersed to continuous phase the separation time and the occurrence probability of the phase inversion phenomenon was increased. Moreover, by increasing the volumetric ratio of the dispersed to the continuous phase the separation time was raised and at a specific impeller speed the separation time did not depend on the impeller speed. By increasing the concentration of SDS up to 40 mg, the phase inversion phenomenon occurred at higher impeller speeds. In the same surface active agent concentration, the impeller speed for the phase inversion occurrence by paddle blade was higher than propeller blade.