Experimental modeling of mean drop size and dispersed phase holdup in rotating disc contactors, using RSM

Abstract

In this study, the behavior of hydrodynamic parameters was investigated in agitated columns including Asymmetric rotating disc contactor (ARDC), Perforated rotating disc contactor (PRDC), Oldshue–Rushton column (ORC), and Kuhni. The effects of various parameters, including rotor speed (rpm), dispersed and continuous phase velocities, interfacial parameters, and type of RDCs on the dispersed phase holdup and Sauter mean drop diameter were studied. The response surface methodology (RSM) based on the central composite design (CCD) approach was applied for the experimental modeling of three standard systems including toluene-water, butyl acetate-water, and butanol-water. Results showed that the enhancement of rotor speed and dispersed and continuous phase velocities would enhance the dispersed phase holdup. PRDC showed the least enhancement of dispersed phase holdup compared to the other three columns. Our investigation demonstrated that Sauter mean droplet diameter decreased with the rotor speed increase, and this declining trend is more appreciable in ORC and Kuhni columns. Additionally, by increasing dispersed phase velocity in the four columns, the droplet size in the ORC column is larger than the columns. However, by increasing continuous phase velocity, subtle changes in droplet size was observed. Based on the experimental data, new correlations have been presented to predict Sauter mean drop diameter and dispersed phase holdup for agitated columns by analysis of variance (ANOVA). The coefficient of determination (R2) was obtained to be 0.9612 and 0.9495 for Sauter mean drop diameter and dispersed phase holdup, respectively, indicating a good correlation between the predicted and observed values of the models.