Model-based design of pressure-driven product removal from stirred suspensions

Abstract

Achieving “mixed-product removal” in a mixed-suspension mixed-product removal crystallizer (MSMPRC), operating with a pressure-driven suspension transfer, is challenging. In this work, single and multiphase computational fluid dynamics (CFD) simulations were used to guide the choice of a suitable withdrawal position, which was found to be that of an immersed tube close to the vessel wall. The chosen withdrawal position was then tested and compared to other withdrawal positions experimentally. It performed as predicted, whereas for the other positions, the degree of dilution (size-independent classification) and of sieving (size-dependent classification) of the product removed increased. Furthermore, the influence of a non-representative withdrawal on an MSMPRC steady-state was investigated using a population balance equation (PBE) model.