Studies On Performance And Structural Optimization Of Rotating Zigzag Bed

As novel gas-liquid contacting equipment, the rotating packed bed using centrifugal force to greatly intensify mass transfer processes, has been successfully applied in absorption, stripping, distillation, extraction process and nano-material production of chemical industries. Rotating zigzag bed (RZB) is a new kind of contactor based on HIGEE technology and characterized by a rotor consisting of a stationary disc fixed with stationary baffles and a rotating disc fixed with rotating baffles. The RZB rotors with different length of stationary baffles were used in the experiments, and their mass transfer/hydrodynamic performance and power consumption were studied using ethanol-water and air-water systems at atmospheric pressure. The effects of stationary baffle length on the mass transfer, pressure drop, and power consumption in the RZB were investigated. The distance between the perforated zone on the rotating baffles and the rotating disc as well as the structure of stationary baffles were changed to further investigate the performance of RZB with the ultimate aim of structural optimization of the RZB. The experimental results were given below.(1) Mass transfer on the stationary baffle makes a major contribution to the overall mass transfer efficiency. The length of the stationary baffle has an obvious effect on mass transfer performance, hydrodynamic, and power consumption of RZB. The rotor with a longer stationary baffle shows a better mass transfer performance. But longer stationary baffle will bring a higher pressure drop and power consumption.(2) On the different parts of the stationary baffle, the mass transfer efficiency is different. Mass transfer intensity in the lower part of stationary baffle turbulent region is greater than that in the upper part of stationary baffle.(3) Compared with the conventional RZB rotor, the rotor with composite stationary baffle can increase the gas-liquid contact area and time, and significantly improve the mass transfer efficiency.In addition, the liquid entrainment in the RZB was also experimentally investigated. Demister device can bring a slight increase of the mass transfer efficiency and more pressure loss, but the power consumption almost remains constant. It seems that the entrainment in the RZB rotor is very small within the load range of this study. The possible reason is that the structure of the RZB can be acted as demister itself.