The PIs plan to look at microchannel reactors utilizing catalyst monoliths for low pressure drop, microchannel heat exchangers for precise temperature control, and active forcing (low-amplitude, low-frequency oscillation) to control gas/liquid distribution, mixing, surface wetting and rates of mass transfer. The active forcing mechanism is scaleable and adaptable to any multiphase reacting system. They will explore underlying mass transfer/fluid flow/ kinetics behavior of the reactors through studies of model gas/liquid reactions, with flow visualization and CFD modeling of the microchannels. The industrial partner, Mezzo Technologies, will provide the micro-heat exchangers and assist in system evolutionary design and fabrication.
Intellectual Merit:
The PIs plan to study the effects of active forcing via pulsed flow, varying both amplitude and frequency independently in a catalyst monolith reaction system. Based on preliminary work on the systems airwater (mass transfer, flow visualization) and á-methylstyrene hydrogenation (reactor studies), they expect enhanced gas-liquid mass transfer, more precise temperature control (due to the micro-heat exchangers), more uniform flow distribution of both gas and liquid, and faster liquid surface renewal than existing heterogeneous catalytic gas/liquid reactor systems, whether based on structured catalyst packing or not. These fundamental issues will be addressed for both a complex hydrogenation (soybean oil) with multiple reaction paths and one of high molecular weight and viscosity (polystyrene hydrogenation). In both cases, gas-liquid distribution and surface wetting strongly affect observed reaction rates. The combination of improvements made possible by active forcing and better distributor design can result in higher observed rates, less catalyst deactivation, and improved selectivities in these serial reactions, where intermediate products are desired. Possible outcomes will be examined through a combination of kinetics, mass transfer, flow visualization, and catalyst characterization experiments. Moreover, the simplified geometry (relative to chaotic systems such as packed beds or bubble columns) allows a more straightforward modeling for the smooth channels.
Broader Merit:
C&E News recently reported that the microreactor market is growing to $100 MM. Monolith microreactors are easily scaleable from gram to tonnage production. Ongoing efforts to use microchannel reactors for both rapid catalyst screening and chemicals production have largely ignored catalyzed gas/liquid reactions. This project contributes to microreactor infrastructure by exploring how structured microchannel reactors can best be applied to such processes. Catalyzed gas/liquid (and sometimes solid) reactions of edible oils and macromolecules figure prominently in future biofuels and biorefining processes, and this project addresses such reacting systems in structured microreactors.
The project will educate graduate and undergraduate students in microreactor and micro heat exchanger design, and heterogeneous catalysis. Students will work several weeks each year at Mezzo Technologies gaining first-hand experience in microfabrication. Mezzo Technologies will gain valuable expertise incorporating heat exchangers in microreactor systems. Undergraduates will participate through an REU supplement and the LSU Chancellors' Future Leaders in Research Program. Results of this work will be incorporated in both graduate and undergraduate classes taught by the PIs, through teaching modules and through a mini-design project that will be made available publicly. The PIs will also develop a video module on microreactor technology for broader dissemination through existing LSU K-12 STEM programs.
