Population Balance Modeling of Pulsed (Packed and Sieve-Plate) Extraction Columns: Coupled Hydrodynamic and Mass Transfer

Abstract

Liquid–Liquid Extraction Column Module (LLECMOD) is a rigorous and comprehensive bivariate population balance framework for dynamic and steady-state modeling of liquid–liquid extraction columns. Within LLECMOD, the user can simulate different types of extraction columns, including stirred and pulsed ones. The basis of LLECMOD depends on stable robust numerical algorithms based on an extended version of a fixed pivot technique (to take into account interphase solute transfer) and advanced computational fluid dynamics (CFD) numerical methods. In this work, mathematical models for pulsed packed and sieve tray extraction columns are developed. The models are programmed using visual digital FORTRAN and then integrated into the LLECMOD population balance model. As a case study, the steady-state performance of pulsed packed and sieve-plate columns, under different operating conditions, which include pulsation intensity and volumetric flow rates, are simulated. The effect of pulsation intensity is found to have a more profound effect on systems of high interfacial tension. On the other hand, the variation of volumetric flow rates has a substantial effect on the holdup, mean droplet diameter, and solute concentration profiles for chemical systems with low interfacial tension. Two chemical test systems recommended by the EFCE are used in the simulations. Model predictions are successfully validated against experimental data by adjusting the steady-state column hydrodynamics, using only droplet coalescence empirical parameters.