Chemical Engineering Seminar

Transport phenomena at interfaces are crucial in a variety of (bio)chemical, analytical, and pharmaceutical processes.  Many process intensification strategies are aimed at improving transport rates, which often find their limitations near such interfaces.  In chemical processes, we find such critical interfaces at e.g. immobilized catalyst walls, membrane surfaces, multiphase reactors, and heat exchangers.  Depletion or accumulation of species near the boundary generates an additional resistance for transport that is often limiting as mentioned catalysts and membranes improve their performances steadily.  We are using microfluidic devices and reactors to control and study transport on a microscopic level.  Our experiments rely on the observation of velocity and concentration profiles near well-controlled boundaries.  Such methods produce great insight in the details of transport mechanisms, and provide some surprising possibilities for enhancement.  In this presentation, I will focus on gas-liquid interfaces within microfluidic devices that provide accurate control of the corresponding bubble interface.  We have studied the influence of gas bubble geometry on the resulting fluid flow and its influence on the interfacial mass transport.  Using the information from these detailed experiments, we were able to design microstructured interfaces that present improved exchange performance.  Finally, such interfaces were fabricated and tested.