APPLICATION OF CONTROLLED COOLING AND SEEDING IN BATCH CRYSTALLIZATION

Some aspects of hatch cooling crystallization in the industrial practice are analysed by computer simulations. The results indicate that without appropriate kinetics and very accurate process control, even the qualitative effects of applying controlled cooling and seeding are highly unpredictable. An increase in product size by applying controlled cooling is likely to be successful only rather randomly and the size distribution becomes broader. A linear or weakly non-linear cooling curve usually produces larger crystals than a natural cooling curve. and a better reproducibility than a controlled cooling curve. Seeding increases both size and reproducibility. but is also likely to increase significantly the coefficient of variation of the product distribution. The product weight mean size and coefficient of variation may increase or decrease at increasing amount of seeds, depending on governing kinetics.