Hydrodynamic Behavior and Mass Transfer Coefficients of Single Liquid drop in Extraction Column

Abstract

Hydrodynamic behavior and mass transfer of several liquid-liquid system has been measured in 150.0 mm column diameter. The column was operated in tow different modes as a spray tower and a perforated plate tower. Experiments were performed using different chemical systems and different needles to obtain drops of different diameters. The relationship between the terminal velocity (Vt) and the down flow of the continuous phase was examined experimentally. Mass transfer coefficients (MTCS) have been measured for single liquid drops rising through non flowing and flowing water and have been compared with the coefficients measured for free rise conditions in an empty column for different systems. The MTCS were determined as a function of drop size, mass transfer direction and down flow of the continuous phase. From the data obtained, it is concluded that the drop size is key variable affecting hydrodynamics and mass transfer processes. The relative velocities between drops and the down-flowing continuous phase were found to decrease as a down flow rate increased. The effect of continuous phase velocity on The MTC is relatively significant with a slight increase in drop size occurring with increasing flow rate. The degree of enhancement of the dispersed phase film coefficients for mass transfer due to the presence of plates has been ascertained. Finally the coefficients for mass transfer from the dispersed phase into the continuous phase ( d→ c) are slightly higher than those for the opposite direction, ( c →d ).