| Abstract: | The objective of this work is to model the effect of simultaneous drop forward-mixing and coalescence-redispersion on the hydrodynamics and mass transfer efficiency of a two phase countercurrent extraction process. Based on the flow mechanism and drop size distribution in extraction columns, a novel model with a simplified sequential algorithm is developed. It is much easier to use, and computationally less expensive, than a direct simulation technique which would typically be a tedious boundary-value iteration method. A new concept of Effective Mass Transfer Coefficient is presented, from which the effect of drop forward-mixing and coalescence-dispersion on extraction performance is directly evaluated from an analytical expression. The results calculated from the model are satisfactorily compared to experimental results obtained from three actual extraction system in two pulsed sieve-plate extraction columns. The relationship between the present model and the diffusion model is discussed and a parameter transformation equation for the two models is given. |
