(84f) Thermodynamics-Based Approach to Crystallization Process Development

Just as vapor-liquid equilibrium-based methods are routinely used to design distillation processes, it is only natural that in designing a crystallization process one should start with solid-liquid equilibrium (SLE), which provides the foundation for further development efforts.  Basically, the SLE behavior imposes thermodynamic limitations as to which components can or cannot crystallize out under a given operating condition.  With the knowledge of SLE behavior, one can easily identify the feasible operating region to get the desirable product as well as the theoretical yield under any given condition.   While it is also crucial to take into account non-equilibrium behavior such as kinetic and mass transfer effects, beginning with SLE ensures that one gets off on the right foot.

This presentation outlines an integrated approach that emphasizes the understanding of SLE phase behavior in the development of crystallization processes. Visualization using phase diagrams greatly enhance the understanding of the SLE phase behavior, leading to an easier analysis.  The use of an SLE model, especially for multicomponent systems, allows convenient representation and interpretation of experimental data.  To illustrate the approach, case studies that are based on or inspired by actual industrial projects are presented.