Experimental Validation of Pulsed Sieve-Plate Extraction Column Models

Pulsed Sieve-plate Extraction Columns (PSECs) are a counter-current solvent equation unit operation used in a variety of industries. They are notoriously hard to design due to their complex hydrodynamics and traditionally this has necessitated pilot plant study or the use of empirical correlations which result in expensive overdesigned columns. This thesis presents the development and validation of a modelling and simulation framework for PSECs using a combination of Computational Fluid Dynamics (CFD) and Compartment Modelling. A PSEC pilot plant was used to generate experimental data to validate CFD-predicted droplet size distribution, mean values and rise velocities with good agreement between the two. The model was further developed to predict mass transfer and accurately model the axial solute concentrations in both phases. Due to the large amount of time required to perform the simulation, an alternative Compartment Modelling approach was developed using the results of a CFD-predicted residence time distribution study and the resulting model accurately predicted mass transfer performance over a range of operating conditions. The model was further developed to predict the hydrometallurgical PUREX (Plutonium, Uranium, Reduction, Extraction) process using tributyl phosphate, uranium and nitric acid and was experimentally validated over a range of operating conditions, successfully predicting the transient evolution of solute concentrations at the column outlets. The resulting modelling and simulation framework provides an accurate predictive tool for predicting PSEC performance and provides a foundation for further exploration of the hydrodynamics and mass transfer performance of PSECs.