Effects of convection, feed-separation and macro-mixing on particle size distributions for double-jet semi-batch precipitation in a stirred vessel

A new approach for describing particle growth has been developed. This model can solve the dynamic population balance equations by integration of ordinary differential equations. The model ensures the number balance as well as a mass balance on the solid, using a free discretised length grid approach. Then, the simulation under both a set of representative fluid mixing cases which varies the extent of macro-mixing (by sets of compartments or zones) and the different degrees of feed-separation (by different addition modes of the two reagents) were performed. It is predicted that joint feeds will give a larger and wider CSD, on the other hand, the most 'extremely' separated feeding positions can compensate for the weakness of the macro-mixing. From this practioners will be able to choose the balance of stirring intensity and feed policies to increase or reduce crystal size, as well as adjust the shape of the CSD itself for double-jet operation.