Influence of the internal crystallizer geometry and the operational conditions on the solid product quality

From an industrial point of view, control of precipitated particles' quality turns out to be crucial. Experiments carried out in a pilot-scale baffled stirred tank with and without draft tube of two different diameters under different process conditions show a great influence of internal geometry and feed point locations on crystal size distribution and morphology of precipitated particles. Several results in contradiction with those expected by intuition show that much more work is needed to elucidate the interaction between mixing and precipitation phenomena in stirred tanks. In this context, the paper provides a frame of reference and some rules of thumb useful to industrial manufacturers for controlling the product quality.