Characterization of crystallization processes with video imaging

Abstract

Crystallization processes are extensively utilized for the purification and separation of a variety of final and intermediate products. Despite its widespread use, in the fine chemicals, pharmaceutical and food industries, crystallization still has many unknowns which can affect the purity, quality and quantity of the crystals produced. As a result, monitoring crystallization processes in order to better understand the underlying science is of utmost importance. To this end, various tools have been developed. They are, however, not without their flaws. The work in this PhD project aims to develop and demonstrate the viability of process video imaging as a reliable methodology for the monitoring, recording and analysis of crystallization processes which either minimizes or removes these flaws altogether. Experimental investigations to test the robustness of the process video imaging focused on three commonly found crystallization processes: melt crystallization in the form of clathrate hydrates, anti-solvent crystallization and cooling crystallization. The results from these investigations were compared to previously reported findings of similar systems in order to examine the degree of accuracy of the process video imaging tool. The significant findings from this work are that the process video imaging can be successfully implemented into melt, anti-solvent and cooling crystallization systems with relative ease. This allowed key crystallization parameters to be determined; including but not limited to: solubility, metastable zone width, crystallization rate and growth kinetics.