Gas flow in a new type of rotating packed bed with gas baffles

Abstract

Cross-flow rotating packed bed is a popular reactor for process intensification, but it has an inherent disadvantage that the gas residence time is very short. A novel gas baffle-rotating packed bed (GB-RPB) was introduced to prolong the gas residence time, and the gas flow in GB-RPB was simulated using a three-dimensional computational fluid dynamics model. The realizable k-ε model was used for the prediction of turbulence and a porous media model was used for the packing. The effects baffle characteristics on gas dynamics and turbulence within GB-RPB were investigated. It was found that mass transfer was significantly enhanced due to the vortex flow pattern and intensified turbulence around baffles. Specifically GB-RPB with inner baffles and outer baffles spaced 20 mm apart (1/3 rotor height) significantly extended the gas residence time, so that the COD degradation rate in pesticide-laden wastewater was increased by over 10 % compared to conventional RPB.