Technologies for Optimisation and Control of Nucleation and Growth for New Generations of Industrial Crystallizers

Abstract

The scope of this thesis is to study new methods for control of the most important phenomena in crystallization processes: nucleation and crystal growth. In order to achieve this, novel process equipment, which utilize alternative driving forces, were developed. It was proven that primary nucleation for solution crystallization can be controlled using laser irradiation. The relationship between creation, expansion and collapse of a vapor cavity induced by a laser pulse and the subsequent nucleation of crystals was both experimentally and theoretically investigated. Regarding crystal growth, it was shown that it can be controlled in an airlift crystallizer, in which, under the right conditions, growth can become the dominant crystallization mechanism, suppressing almost completely secondary nucleation. This air-mixed crystallizer enables the production of crystals with high quality and offers a large flexibility of the final crystal size. The research presented in this thesis brings new alternatives for control of nucleation and growth of the crystals and thus new methods for flexible process operation and enhanced product quality in industrial crystallization processes.