Optimal design of continuous crystallizers

Within the project Improved process operation via rigorous simulation models (IMPROVISE) in the Institute for sustainable process technology (ISPT) closing the gap between offline and online use of rigorous simulation models has been dealt with. To this end, batch crystallization process operation and modeling were studied, identifying issues such as batch to batch reproducibility, controllability and observability [1]. These pose several problems in the realization and use of online model-based strategies for process control and monitoring which can guarantee the achievement of the desired production targets.
These motivate the research efforts in designing continuous crystallization technology, which may be able to overcome the abovementioned limits of the batch operation. Accordingly, this poster addresses the optimal design of continuous crystallizers. The key process variables (crystallization temperature, number of stages, crystallization volume, residence time) of single stage mixed-suspension mixed-product removal (MSMPR) crystallizers and multiple stages MSMPRs are optimized by minimizing a cost function consisting of equipment and utility costs. The constraints for the above mentioned optimization problem are derived from the definition of production targets (e.g., minimum allowed yield, daily production, relevant particle size distribution attributes of the final product) and upstream operation (e.g., temperature and flow rate of the inlet flow).
The pros and cons of using the proposed configurations are discussed, in the understanding that the effort to propose control strategies for the most convenient configuration will be addressed as future research.
The study has been executed with the gCRYSTAL package.