Archived: Cryogenic Flow Chemistry Made Easy : The Skid Concept for Pilot Plant Scale
Date: 17 March 2020
Cryogenic chemistry is extremely fast and very energetic, with a heat production potential easily reaching 10 to 100 kW/L. Flow chemistry R&D has shown that continuous plug-flow micro reactors are far better suited to deal with such challenges than conventional fed-batch reactors. Micro reactors allow the intrinsic reaction kinetics to run freely. It’s the high heat transfer capability which is the key feature that tempers hot spot formation and secures selectivity. High performance of the micro reactor follows from design features such as channel dimension and geometry (QbD). Combined with a process control system to maintain the validated operating window, this results in a highly productive, smaller and more economic process.
3D metal printing proved to be the ideal manufacturing technology for such high performance micro reactor modules. It offers the required freedom of design to build-in the performance attributes while maintaining a favorable cost level. The modularity allows easy (re)configuration to adapt the system to a variety of cryogenic chemistries.
Nevertheless scale-up of such a fully continuous micro reactor system to plant scale proves to be a hurdle for pharma industry. This presentation describes how we tackled such a scale-up. To begin it was clear that the skid should be capable of running several different cryogenic chemistries at pilot plant production capacities 1 – 3 kg/h. The required flexibility is coming from the modular configuration of the reactor set-up. All the modules that operate at low temperature are positioned in an isolated ‘cold box’ to prevent formation of a thick layer of ice on such vital parts. The auxiliary equipment is placed outside of this cold box at ambient conditions. The skid is small and mobile and fits into a drive-in hood. Operation is semi- automated. The skid needs to be connected to reagent storage vessels, utilities and product receivers. Once in operation the PLC takes care of process control, data logging and safe guarding.