Scale-up of multiphase micro/milli channel reactors

Microstructured reactors are already at the production scale for single phase processes, for example, in fine-chemical applications in liquid phase and in fuelprocessing in gas-phase. However, gas-liquid micro processing remains mostly restricted to laboratory scale due to the complexity and expenditure needed for an adequate numbering-up with an equal distribution of the gas and liquid flows over multiple microchannels. Previously, we developed a barrier-based gas-liquid flow distributor. It was used for a water-nitrogen flow under the Taylor flow regime. Gasliquid channeling was prevented and a flow uniformity of more than 90% was achieved. Based on this "barrier channels" concept, a design strategy was developed for reaching sufficient flow uniformity. This strategy was used for designing the ‘Barrier-based Micro/Milli Reactor’ (BMMR). The BMMR is a modular reactor for conducting a multiphase (gas-liquid) reaction in parallel micro or milli channels at a pressure up to 20 bar and a temperature up to 200 oC with a liquid flow rate of 150 mL/min. According to this design strategy, the appropriate fabrication techniques were chosen to deliver a flow uniformity of more than 90% in the BMMR. In the barrier channels, the fabrication tolerance (s) of less than 2% was realized via wet chemical etching in glass. Powder blasting in glass was used in the mixer channels to achieve s less than 5%. Milling in stainless steel was used in the reaction channels to reach s below 10%. To verify the developed design strategy, the flow uniformity at different operating conditions has been investigated in the BMMR under cold flow conditions (without reaction). The influence of channel blockage on the reactor performance has also been studied.