Method Coupling Computational Fluid Dynamics with Ternary Phase Diagram for Anti-solvent Crystallization

Abstract

A computational fluid dynamics（CFD）method coupled with a ternary phase diagram is developed to simulate anti-solvent crystallization. As a model case, KCl–ethanol anti-solvent crystallization in a Y-shaped mixer was adopted for this study. Flow and mass concentration in the Y-shaped mixer are simulated using CFD. Local supersaturation is calculated based on the effects of anti-solvent concentration on physical properties such as solubility and the diffusion coefficient. Crystal nucleation and growth are calculated using a population balance model. Effects of anti-solvent concentration on the nucleation and growth rate are also considered. To couple CFD with crystallization process calculation, notation of the concentration and time step size are specifically investigated. The mixing state and crystallization process in the KCl–ethanol system, which are difficult to measure, were simulated successfully. Results demonstrate that this calculation method is an effective means to quantify the effects of local distribution of anti-solvent concentration on the crystallization process.