Compartment‐model for the simulation of the separation performance of stirred liquid–liquid‐extraction columns

Abstract

AbstractFor detailed simulation and evaluation of stirred extraction columns a CFD based compartment‐model was developed. Instead of simulating all effects in a computational expensive PBE‐CFD‐model, the velocity field calculation of the continuous phase is decoupled from the calculation of the dispersed phase (one‐way coupling). In CFD only the continuous phase is simulated and the resulting velocity profile is used in the compartment‐model to simulate the drop movement, coalescence, breakage and mass transfer for a representative number of drops (Monte‐Carlo Method). This decoupling has a major impact on the calculated fluid‐dynamics. Thus, the velocity profile of the CFD results is modified in the model to account for phase interaction. The compartment‐model is applied for the simulation of a Kühni extraction column with the system toluene/water/acetone. The simulation results, namely holdup, drop size and concentration profiles over the column height, are in good agreement with experiments for different loads and different stirrer speeds.