Authors:Lukas Hohmann, Safa Kutup Kurt, Sebastian Soboll and Norbert Kockmann
For complete chemical processes, downstream operation steps are essential, but on a miniaturized scale, they are not so far developed as the microreactors. This contribution presents three different unit operations for phase and component separation. Liquid—liquid extraction is often performed in columns, which were miniaturized for higher separation efficiency and flow rates suitable for processes in flow chemistry. Two-phase mass transfer processes in capillaries benefit from rapid final phase separation, which can be performed in an in-line phase splitter based on different surface wetting behavior. Crystallization is often a final purification step, which is performed in a continuously operated helical tube setup with narrow residence time distribution. For all unit operations, design criteria are shown with typical applications. The methodology of downscaling of known equipment and employing typical microscale phenomena such as good flow control, laminar flow, or dominant surface forces leads to successful equipment design.