(442b) Simulation of Liquid-Liquid Dispersions in Continuous-Flow Pump-Mixer with CFD-PBM

Liquid-liquid dispersions in continuous-flow pump-mixers are frequently used in the solvent extractions of rare earths. The extent of mixing is commonly judged by hold-up and drop size distribution, which are affected by the interaction of droplets seriously. In this work, droplet breakage and coalescence in turbulent flow are simulated via computational fluid dynamics (CFD) simulations combined with population balance model (PBM). The drop size distributions and hold-up of dispersed phase are predicted in different dispersions created in a continuous-flow mixer with a both sides shrouded turbine with radial trapezoidal blade(BSTRTB), with aqueous phase as continuous and organic phase as disperse phase. Effects of impeller speed, flow ratio and physical properties on hydrodynamics features are investigated. Simulations are performed with multiple reference frame (MRF) model and Eulerian-Eulerian two-phase mothed. Two population balance models, differing in droplet breakage kernels, have been evaluated. The experimental data of velocity field, obtained by using particle image velocimetry (PIV), and hold-up in system of kerosene/water has been used to compare the models for their ability to predict the mixing characteristics. The better one is applied to forecast the mixing features of the quasi real rare earth extraction systems.