Effect of Operating Conditions on the Characteristics of Crystalline Particles in a Cascade-Type Crystallizer

Abstract

The continuous crystallization process has attracted attention, because of its high energy efficiency, low operation cost, and high product consistency. Recently, a cascade-type crystallizer (CTC) based on Couette–Taylor (CT) and mixed-suspension mixed-product-removal (MSMPR) equipment has been proposed as a novel continuous crystallizer. However, the relationship between the operating conditions and the characteristics of crystalline particles in the CTC have not yet been clarified. This Article describes the effect of the load factor for CT equipment, which is an operating parameter in the CTC, on the characteristics of crystalline particles. Scanning electron microscopy (SEM) observation and characterization revealed that the characteristics of crystalline particles, such as size, shape, size distribution, and yield, were strongly dependent on the load factor of CT in the CTC. Furthermore, evaluation of the mechanism using a classic population density plot indicated that the CT equipment functions as seeding equipment for MSMPR in the CTC. These findings are suitable for designing an operation strategy to produce crystalline particles with favorable characteristics, using the CTC for a continuous crystallization process.