MICROCHANNEL DEVICE FOR DROPLET GENERATION, MIXING, AND PHASE SEPARATION FOR CONTINUOUS COUNTER-CURRENT FLOW EXTRACTION

摘要

Process intensification is a major goal in chemical engineering, which is often obtained by miniaturized devices with enhanced heat and mass transfer characteristics. This work shows a microchannel device for liquid-liquid extraction and reactions with integrated droplet generation, enhanced mixing and phase separation. Monodisperse droplets with diameters in the range from 0.3 to 0.7 mm are generated by co-current jet flow with different operating modes of aqueous and organic phase. Flow regime maps indicate operation conditions for small and monodisperse droplets of the organic phase. A glass plate with a single microstructured channel serves for sufficient residence time and intensive mixing between the two phases. At the outlet, a wider channel leads to droplet coalescence and agglomeration at a hydrophobic wall and outlet tube for the organic phase. A complete phase separation was possible over a wide range of flow rates. The closed channel setup of droplet generation, mixing and phase equilibrium, and finally phase separation allows for counter-current switching of the plates. This arrangement needs additional pumps to overcome the pressure drop over the plates, at least one pump more than the number of plates.