(417b) Characterization of Mixing and Solid Settling in Continuous Flow Slurry Reactors Using Computational Fluid Dynamics

Manufacturing of specialty chemicals have traditionally been performed in large-volume batch vessels with relative operating simplicity but at the cost of limited efficiency. Continuous processing offers significant advantages with respect to process intensification and scale-up but poses new challenges due to the limits in types of operations available. One major concern in batch-to-continuous process development comes from the mixing concerns related to heterogenous or multiphase reactions. The mixing considerations for batch operation differ substantially from a continuous processing approach, making the translation of technology and scale-up much more challenging. The present study investigates the mixing considerations for a slurry to slurry reaction in a scalable agitated baffle reactor (Stoli Chem, Wellesbourne, UK) which offers the benefits afforded by stirred-tanked reactors in series while still maintaining continuous production capabilities at scale. In this work we have used computational fluid dynamics (CFD) to characterize the mixing regimes and solid settling dynamics of a slurry reaction, to predict operating conditions that enable successful scale up from bench to pilot scale production of material with limited plugging concerns and comparable reaction kinetics in contrast to standard batch scale operations. Transient Large Eddy Simulation CFD models based on the Lattice Boltzmann approach were developed to characterize the flow hydrodynamics and particle suspension behavior within the flow reactor at two different length scales. Simulations were compared and validated against experimental data enabling the successful translation of reactor technology from batch operation to continuous manufacturing.