Study On Performance Of Cross-Flow Rotating Bed

Rotating packed bed （also called RPB） using centrifugal force to intensify mass transfer and micromixing, is a new type of high-performance mass-transfer equipment. The centrifugal force far larger than gravity makes gas-liquid contact turbulently in the rotating bed, which intensifies mass-transfer process and enhances mass-transfer efficiency.The contact mode of gas and liquid in previous RPB mainly is counter-flow. Because of the higher pressure and smaller flux of counter-flow, it is not applicable for higher flux mass and heat transfer. For the purpose of increasing the the flux of gas and liquid, changing the contact form of gas and liquid from counter-flow to cross-flow was made.Based on the advantages and the overcome of disadvantages of counter-flow packed bed, series of cross-flow concentric-ring rotating bed including cross-flow concentric-ring rotating bed and cross-flow concentric-ring rotating packed bed have been developed, whose advantages are even flow area, invariable gas velocity, small gas phase resistance, high mass-transfer efficiency and throughput.In this paper, the gas pressure drop, power consumption and mass-transfer of cross-flow concentric-ring rotating bed and cross-flow concentric-ring rotating packed bed with five kinds of packing have been comprehensively investigated using the system of air-water and acetone-water. The experimental results show that the gas pressure drop, power consumption, overall volumetric liquid-phase mass-transfer coefficient depends on gas flow rate, gas flow rate, rotating speed and the size and porosity of packing. The ranges of gas pressure drop, power consumption, overall volumetric liquid-phase mass-transfer coefficient of cross-flow concentric-ring rotating bed are respectively 127～1108Pa、495～1250W、0.007～0.027s^-1. The ranges of gas pressure drop, power consumption, overall volumetric liquid-phase mass-transfer coefficient of cross-flow concentric-ring rotating packed bed are respectively 157～3177Pa、519～1190W、0.01～0.31s^-1. The gas pressure drop, power consumption and overall volumetric liquid-phase mass-transfer coefficient were measured and correlated with theoretical model. The comparison of the calculating values of the theoretical model with the experimental ones indicated that the relative error between them is less than 10%. The values caculated by correlative expressions are in good agreement with the experimental results.From the comparison of gas pressure drop, power consumption and mass-transfer between cross-flow concentric-ring rotating bed and crossflow concentric-ring rotating packed bed with five kinds of packing, it can be concluded that though the gas pressure drop and power consumption of cross-flow concentric-ring rotating bed are lower than that of cross-flow concentric-ring rotating packed bed, the performance of mass-transfer and trend with the gas flow rate, rotating speed and liquid flow rate in cross-flow concentric-ring rotating packed bed is better than that of cross-flow concentric-ring rotating bed. The smaller the size of packing is, the better the performance of mass-transfer is. The height of mass transfer unit of cross-flow concentric-ring rotating packed bed was one order of magnitude lower than that of the conventional gas-liquid mass-transfer equipments under the same operational condition. The proper size packing of cross-flow concentric-ring rotating packed bed can be used in the industrial condition.