CONTINOUS MULTI-PHASE FLOW REACTOR FOR SMALL AND LARGE FLOW CAPACITIES THAN L/MIN

Abstract

Multiphase flow processing in flow reactors holds great promises for diverse applications in fine chemicals and materials synthesis primarily due to its precise control over the flow, mixing and reaction inside or between each phase. Even though, flow reactors have shown superior performance, so far batch reactors still dominating the landscape for industrial manufacturing in the pharmaceutical and fine chemicals. Nonetheless, the base of switching to continuous flow reactors is making its way. Recently, a good article has been published which summaries the complexity of introducing new disruptive technology and why flow reactors are taking so much time to make it industrial scale manufacturing. (1). One of these factors is the need to reduce the investment and technological risks of scale-up which we address here. In this paper, we present an effort into developing a scale-up methodology to smoothly bridge the gap between continuous flow laboratory reactors and those for industrial scale manufacturing. The methodology relies on the concept of numbering-up, placing multiple reaction channels in parallel to increase the flow capacity rather than scaling-up the reaction channel dimensions. The key to this methodology is the flow distribution to ensure equal flow rate and temperature to all parallel reaction channels (2). The second key is the reactor assembly and design that is suitable for industrial scale fabrication and manufacturing. A case study to demonstrate this reactor and methodology will be presented. First, the flow uniformity for segmented gas-liquid flow will be demonstrated in a hydrodynamic study. Two criteria for obtaining uniform segmented flow distribution in the system are found as a proper pressure balance in the system (i.e., a high ratio of pressure drop in the barrier channels to that in the reaction microchannel) and the avoidance of bubble coalescence. Second, the gas-liquid segmented flow distribution performance of the reactor is evaluated using fluid pairs with different liquid phase viscosity and surface tension properties. Third, the reactor is tested using a hydrogenation reaction as an industrially relevant model reaction. Finally, the scalability of this reactor design is demonstrated via combining two stacks of such multi-layer microreactors the liquid throughput of which is possible to reach about 1 ton per day. References 1. Roberge M.D. “The complexity of technology implementation: flow versus batch processing”. Chimica Oggi-Chemistry Today. vol. 30(5) 2. M. Al-Rawashdeh, F. Yu, T. A. Nijhuis, E. V. Rebrov, V. Hessel and J. C. Schouten. “Numbered-up gas-liquid micro/milli channels reactor with modular flow distributor”, Chem. Eng. J., 207-208, pp.645-655, 201