Simulation and experimental evaluation of seed and supersaturation control design approaches for crystallisation processes

The paper presents a methodology for the systematic design of operating recipes for batch cooling crystallisation systems with the aim to produce a desired target crystal size distribution. The population balance model is solved using the method of characteristics under the assumptions of a constant supersaturation and growth dominated process, yielding a simplified analytical expression for the size distribution. A method is proposed for designing the seed distribution, which can be used in conjunction with the supersaturation set-point design to shape the product crystal size distribution (CSD). The approach designs the seed as a mixture of crystals obtained from standard sieve analysis. A second approach is also proposed which uses dynamic seed addition during the batch to control the final size distribution.