Experimental study and simplified mathematical description

The purpose of this paper is to investigate the concept of preferential crystallisation focussing on aspects of quantification and application from the engineering point of view. In experiments performed, the amino acid threonine was used as a model system. Application of on-line polarimetry in combination with measurements of an on-line density meter proved the general applicability of this method in order to monitor directly the resolution progress, to recognise the region of "safe" resolution and to gain information about the crystallisation kinetics. For the evaluation of the crystal growth kinetics of the desired enantiomers the method of moments was applied to analyse isothermal single-step crystallisation experiments. A population balance model is used in order to simulate the time changes of liquid phase composition during the preferential crystallisation process. Finally, first experimental results regarding a cyclic operation mode will be presented.