Design and Control Techniques for the Numbering-up of Capillary Microreactors with Uniform Multiphase Flow Distribution

The results of experimental studies on the parallelization of both single-phase and biphasic liquid-liquid slug flow in capillary microreactors are presented. Various flow distributor designs were investigated with respect to the uniformity of liquid-liquid flow in eight parallel capillaries and the two most promising concepts were identified. A novel multichannel phase splitting unit was installed at the downstream end of the capillaries to ensure well-defined phase separation. Further investigations on more complex reaction systems, in which the hydrodynamics depend on conversion and/or selectivity (e.g., polymerization), suggest that an active flow control for individual capillaries will be necessary in such cases. The uniformity of flow rate and flow structure could be achieved using a noninvasive capacitative measurement to characterize the flow in conjunction with specially developed microvalves and actuators for the regulation of flow rates and the manipulation of slug flow structure in each capillary.