Crystallization operations are unit operations that are commonly difficult to handle. From the perspective of the crystallization rate, cooling or evaporation can be chosen as the driving force. It must also be decided whether to use a solvent as an environment where crystallization occurs. Furthermore, it is necessary to decide various factors in the crystallization process development, such as selecting whether to use seed crystals or not. These choices affect the purity, shape and particle size distribution of the resulting crystals. Since the investigation of population balance (particle number balance) is effective as a method of crystallization analysis for examining the crystallization process, we will introduce this method here. (Y. Kumagae)
