Scale-up of continuous and semibatch precipitation processes

A segregated feed model linked to the population balance, which includes mi cromixing and mesomixing effects together with crystallization and agglomer ation kinetics, is proposed for scaling up reactive precipitation processes . The model is solved using kinetic parameters extracted from laboratory-sc ale experiments together with local mixing parameters obtained from a compu tational fluid dynamics simulation. Predicted particle size characteristics are compared with experimental data collected on three different scales of operation (range 0.3-25 L) using the aqueous calcium oxalate system. The h ybrid precipitation-mixing model accurately predicts mixing effects observe d during the continuous mode of operation, including a maximum in the mean particle size and coefficient of variation with increasing power input on e ach of the three different scales. The influence of mixing on the mean part icle size in semibatch operation is found to be more pronounced owing to th e direct mixing of the feed solution with the other component already prese nt in the reactor, and is also correctly predicted by the hybrid model.