A novel Liquid Distributor Concept for Rotating Packed Beds

Multi-rotor RPBs (MR-RPBs) are a promising way to intensify mass transfer by exploiting the centrifugal field while achieving high separation performance. Reaching the full potential of the separation performance of MR‑RPBs requires a uniform liquid distribution in each rotor. As conventional liquid distributors like nozzles can only be used at the pressurized inlet of the liquid a new concept is needed for distribution on additional rotors. For this reason, a novel liquid distribution concept named rotating baffle distributor (RBD) was developed. It has a compact design and exploits the rotational speed of the rotor. High-speed camera analyses showed that a minimum rotational speed of 600 r/min was required for axial liquid distribution with water at ambient conditions. CT scans revealed a uniform liquid distribution in the circumferential direction using RBD with 36 baffles. Furthermore, RBDs with 12, 24, and 36 baffles were applied to the distillation of ethanol-water at atmospheric pressure under total reflux using a one-rotor RPB (1R-RPB). The F-factor was set up to 2.3 Pa^0.5 and rotational speeds up to 1200 r/min. The results were compared to the same distillation experiment in the 1R-RPB using the conventional liquid distribution, i.e. spraying the liquid on the packing via a full-jet nozzle. The distillation study revealed that the RBD with 36 baffles showed one theoretical stage higher separation performance at rotational speeds > 900 r/min compared to the conventional liquid distribution. Those results suggest that the RBD is not only multi-rotor compatible but also provides uniform liquid distribution while being easier to adjust and operate than the conventional nozzle setup.