Study On Micromixing Performance Of Ultra High Speed Rotating Packed Bed

The current chemical industry has a wide range of processing processes under large volume ratio conditions,such as extraction enrichment,wastewater treatment and other processes.Traditional process equipment such as extraction towers,stirred kettles and other reactors have disadvantages such as liquid flooding,long start-stop stabilization time and generally high energy consumption due to their structural characteristics.High-gravity reactors offer excellent performance in fluid mixing.This topic uses Ultra High Speed Rotating Packed Bed(UHS-RPB)which can provide ultra high-gravity environment,coupling high-gravity technology and falling film mixing technology,combined with innovative feeding method,which provides a new equipment scheme for reducing energy consumption and improving mixing effect.Micromixing performance is one of the important evaluation indexes of reactor performance,so it is important to adopt a suitable method to study and improve the micromixing performance of the reactor.In this study,a modified study was done for the iodide-iodate system.The segregation index is usually used as an important parameter to characterize the degree of micromixing,and its calculation process requires an accurate initial proton concentration.The proton source sulfuric acid commonly used in this system has the disadvantage of incomplete dissociation,which can lead to errors in the calculation of the segregation index.In this study,the trends and numerical gaps of the segregation index were investigated in an ultra-high speed rotating packed bed reactor,a stirred kettle reactor,and a millimeter channel reactor with different initial proton concentrations when perchloric acid and sulfuric acid were used as the proton sources of the system,and the correction coefficient were presented.The micromixing performance of UHS-RPB was investigated by the modified iodide-iodate system.The trends of the segregation index XSunder different reactor component structures and various operating conditions were mainly investigated,and the micromixing times of the reactor under optimal conditions were obtained and compared with other reactors.The main findings of the study are as follows:(1)In the study of the effect of iodide-iodate system proton source on the segregation index,the segregation index obtained with perchloric acid as the proton source for the iodide-iodate system was 1.3 times higher than that obtained with sulfuric acid as the proton source for the iodide-iodate system at the same initial proton concentration.The proton concentration was supplemented at a ratio of 1.3 times the concentration of primary sulfuric acid, and the segregation index obtained was compared with that obtained when the corresponding concentration of perchloric acid was used as the proton source of iodide-iodate system.A comparative analysis of the experimental results showed that the difference between the two segregation index was always less than ±15% at all experimental concentration conditions.(2)In the study of micromixing performance,the effects of packing porosity,wettability of the inner wall surface of the falling film plate and operating conditions such as rotor speed,liquid flow rate,hydrogen ion concentration and viscosity on the micromixing performance of ultra high speed rotaing packed bed were systematically investigated.The segregation index Xs tends to decrease with the decrease of packing porosity,decrease with the increase of hydrophilicity of the inner wall surface of the falling film plate.The segregation index decreases significantly when the rotor speed is accelerated,the influence of liquid flow rate on the segregation index is non-linear,showing a trend of decreasing and then increasing.Reducing the hydrogen ion concentration and viscosity is beneficial to improve the micromixing performance of the reactor.Combined with the experimental results of this project,the tmrange of micromixing characteristic time of the reactor is 0.01-0.1ms.