A continuous multi-stage mixed-suspension mixed-product-removal crystallization system with fines dissolution

This work demonstrates how crystal particle size is affected by the addition of fines dissolution in a mixed suspension mixed product removal (MSMPR) cascade system. The cooling crystallization of paracetamol in water was used as a case study. Two MSMPR cascade configurations were evaluated: (i) nucleation-growth (NG), and (ii) nucleation-dissolution-growth (NDG). Simulation results demonstrate that adding a dissolution step in the MSMPR cascade configuration increases the average product crystal size. Larger crystals and a narrower distribution were obtained due to the removal of fine crystals through the continuous process. However, a small decrease in the achievable yield was observed. Experimental results also showed a similar effect on the final mean size and CSD. The results demonstrate that a dissolution stage can be optimized to increase the final crystal size and CSD by varying the dissolution temperature to optimize the CSD with minimum effect on the achievable yield.