Simulation of Dissociation Extractive Crystallization Process in Ionic Media

Dissociation extractive crystallization (DEC) is a novel separation process that shows its efficacy in the separation of close boiling and isomeric components, where the conventional methods are not effective. The intention of this study is to develop a theoretical basis for solution phase behaviour and to provide a simulation model for the process in ionic media. The model utilizes the UNIFAC method and it can predict the concentrations of all species after adding reagent as well as the fractional recovery of the process. The validity of the model has been assessed by the experimental results achieved in the separation of dichloroacetic acid (DCA) and trichloroacetic acid (TCA) in aqueous media. To enable the model for such a task, the UNIFAC has been modified to be able to predict the activity coefficient of neutral molecules in the presence of the ionic particles. The experimental and predicted results present on ternary solid-liquid phase equilibrium diagrams for the DCA – TCA – water system. A good agreement is found between the predicted results from the separation model and the experimental ones for such a complex system.