Theoretical Modeling of Mixing Quality and Axial Hold-up Distribution for Liquid-Liquid System in Agitated Flow Mixers

New theoretical based models to describe the mixing quality and the local dispersed phase hold-up distributions in the axial direction of a continuous flow mixer have been developed and applied to predict the experimental results. The models relate the mixing index and axial hold-up distributions to a Peclet Number, the average dispersed phase hold-up, the input flow rates and the physical properties of the dispersion. The developed models offer a new understanding of the nature of the mixing process in continuous mixers with two liquid-liquid immiscible phases in flow. Experimental work was performed to measure the mixing index and to measure axial dispersed phase hold-up distribution using Laser Transmission Technique (LTT) in a mixer setup. The experimental results were used in validating the models. The experimental and the predicted data agreed well for a wide range of impeller speeds/flow ratios. Theoretical formulae to describe the local hold-up distributions in the axial direction for only one of the two phases in batch and in flow operation processes have also been developed.