Studies of Drop Behavior and Prediction of Sauter Mean Drop Diameter in Various Rotary Agitated Extraction Columns

Knowledge of droplet behavior is one of the most important criteria for determination of mass transfer kinetics for choosing the type of liquid-liquid extraction columns. Mean drop size data of dispersed phase droplets in continuous phase were obtained for various rotary agitated liquid-liquid extraction columns. The effects of operational variables such as rotor speed and dispersed and continuous phase velocities were investigated. In addition, the effect of mass transfer direction was studied on the Sauter mean drop diameter. The Sauter mean drop diameter was influenced mainly by mass transfer direction and agitation speed. In this research work, previous experimental works in agitated extraction columns (RDC, ARDC, PRDC, Scheibel, Oldshue-Rushton and Kühni columns) are reviewed. Calculations with the literature correlations cannot predict experimental data, thus unified correlations considering the physical properties, operating conditions and geometric parameters were provided to predict the mean drop size (d32). The results of the proposed correlation were compared with the experimental data obtained from the literature and the present investigation. This correlation covers several physical systems for various rotary agitated extractors. Findings of this study demonstrated that the proposed correlation leads to an accurate prediction for the Sauter mean drop diameter in rotary extraction columns.