Studies On Structrue Modification And Optimization Of Rotating Zigzag Bed

As an entirely novel and efficient gas-liquid contactor,Rotating Packed Bed(RPB)can greatly intensify the process of mass transfer and micromixing using centrifugal field to replace the gravitational field.Rotating zigzag bed(RZB)is one of the rotating beds that have been successfully applied in industries,which is structurally characterized by a rotor combining rotating components with stationary components.Rotating components include rotating disc and rotating concentric baffles.Stationary components include stationary disc and stationary concentric baffles.RZB exhibits many superior features such as high mass transfer efficiency,running without liquid distributor,ease of middle-feed.However,it also shows some disadvantages,such as high pressure drop,complex structure,and liquid backmixing.In this thesis a novel kind of rotating zigzag bed(nRZB)based on RZB was proposed.The innovation of this structure is elimination of stationary concentric baffles,and rotating concentric baffles with different holes to control gas-liquid contact.The mass transfer performance of the nRZB was studied by ethanol-water system.Effects of F-factor and rotor speed on pressure drop and mass transfer performance of the nRZB were investigated.The experiments show that:(1)Pressure drop of the nRZB increased with the increase of the F-factor and rotating speed.(2)The average theoretical plate numbers per radial meter(NT/H)increased with the increase of rotating speed,and increased with the increase of F-factor before it reached a certain value.(3)The comparison between nRZB and RZB of same dimension indicated that the pressure drop of nRZB was 1/5?1/3 that of RZB;the liquid kinetic energy loss and the shaft power in nRZB were less than those in RZB about 10%?30%;but the average theoretical plate numbers per radial meter(NT/H)in nRZB was less than that in RZB about 20%?40%.Compared with RZB,nRZB was more suitable for those applications with large throughput and low power consumption.The structure optimization of nRZB had been made in three respects:the liquid distributor,seal structure,fluid flow patterns.The experimental results show that the optimal structure is the rotor without liquid distributor,using gland seal and the concentric baffles which makes gas-liquid crossflow contact.The mass transfer performance of the optimized nRZB is equivalent to that of the RZB,but its pressure drop is much smaller than that of the RZB.Compared with RZB,nRZB have obvious advantages in throughput and power consumption.The study also experimentally investigated liquid capacity for rotor design.The correlation has been established based on the experimental data,which will provide a theoretical guide for rotating bed design.