Hydrodynamics of a Pulsed Sieve Plate Extraction Column

Abstract

Hydrodynamic characteristics, such as drop size, dispersed phase hold-up and flooding have been studied experimentally in a pulsed sieve plate extraction column of 0.076 m diameter. Geometrical parameters like perforation diameter, plate spacing and fractional free area (FFA) of sieve plate and operating parameters, such as pulse velocity and superficial velocities of dispersed and continuous phase, were studied using kerosene-water system. The drop size was reduced with decrease in perforation diameter, plate spacing, FFA and pulse velocity. Dispersed phase hold-up was found to be a function of drop size and superficial velocity of dispersed phase. At pulse velocity of 0.025m/s the parabolic behaviour with maxima at the transition from mixer-settler to dispersion regime of flooding curve has been noticed for all the different geometrical conditions. The maximum mass transfer interface together with utmost throughput was obtained at perforation diameter of 0.003 m, plate spacing of 0.05m and FFA of 0.2. The optimal operating parameters were pulse velocity of 0.025 m/s and superficial velocity of 0.006 m/s using organic to aqueous ratio (O/A) of 1:1. The drop size attained at these conditions was 0.0015 m with dispersed phase hold-up of 18%. The correlations developed can be used for the prediction of hold-up and drop size.