Using Computational Modeling to Control and Optimize the Crystallization Process

Crystallization processes are used across the chemical, petrochemical and pharmaceutical industries. In the chemical industry, the potash and caustic industries use crystallization as a means to produce bulk chemicals and also as a separation technology for purification. The fine chemical and specialty chemical industries use crystallization processes to produce various high-value organic compounds. In pharmaceutical manufacturing, crystallization processes are frequently used to manufacture active pharmaceutical intermediates (APIs). Yet, in spite of its broad use, the crystallization process is not well understood from a scientific viewpoint. Many of the process parameters are coupled and are hard to study or analyze separately. The hydrodynamic issues of non-ideal mixing become important in large scale crystallization processes. The kinetics of nucleation and growth affect the final crystal shape and size. The supersaturation ratios and profiles also affect crystal shape and size. Given the vast complexity, it is still useful to study different components individually and gradually couple the phenomena. This article describes some of the hydrodynamic challenges in crystallizer process control and scale-up. Kumar Dhanasekharan, Fluent Inc. • Kuochen Tsai, Dow Chemical Company • Terry Ring, University of Utah