RESUMO
This paper describes different flow management strategies for a connected purification process which includes two polishing steps, virus filtration and tangential flow filtration. Connecting these unit operations avoids introducing large intermediate product pool vessels in small manufacturing facilities. However, a connected-downstream process requires an elaborate control strategy enabling multiple unit operations to function as a single unit. The key strategy to enable the connected-downstream process is a robust management of flow disparities among unit operations. During a typical ultrafiltration step, product concentration increases as mass is added to the retentate tank, leading to a permeate flux decline. In a connected-downstream process, the inlet stream is directly connected to the prior unit operation and any decrease in permeate flow rate could cause a flow disparity. Four different flow management approaches are proposed to manage potential flow disparities and their advantages and challenges are discussed. Bench-scale results of these strategies are presented and evaluated.
