Flow Reactor Technologies and Scale-up Methodology
Dominique Roberge,
Group Leader,
Lonza Group Ltd
Micro-reactors potentially offer enhanced transport rates including wall-to-fluid heat transfer due to relatively small channel dimensions and high surface-area-to-volume ratios when compared to batch or larger-scale continuous flow reactors. Notwithstanding the fact that a single micro-reactor is not a general solution to all type of reactions, Lonza developed a toolbox approach where the preferred reactor system is chosen for the given reaction rate, reaction network, and phase type. This toolbox encompasses the use of micro-structure plates where beneficial, namely during the intense mixing/heat exchange portion of a reaction, while more conventional modules like a coil or tubular heat exchangers are used afterward for an effective increase in volume. The scale-up of production using micro-structures is often limited by the pressure drop, and a plate type reactor is generally more straightforward to scale up than a coil reactor. Figure 1 shows a Mix-Then-Reside (MTR) plate for homogeneous reactions requiring intense heat exchange capabilities and contrasted to a Mix-And-Reside (MAR) plate designed for multi-phase applications. This work is focused on characterizing and developing models for the overall mass transfer performance of MTR and MAR plate reactors but also COIL-type reactors. The results are then used to understand scale-up and it will be shown that the hydraulic diameter of the mixing zones can be adjusted for various flow rates via the 3/7 power rule.
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