Study On Intensified Gas-liquid Mass Transfer Of Pore-array Jet Tube-in-tube Microchannel

The microchannel can significantly enhance the mass transfer,heat transfer and mixing process,and have the advantages of high process efficiency,convenient amplification and high safety,due to its small characteristic scale and high specific surface area.The pore-array jet tube-in-tube microchannel(PA-TMC)combines the advantages of jet enhanced transfer and microchannel,and has excellent micro-mixing and liquid-liquid mass transfer performance.At the same time,because the annular space is used as a microchannel,it has a large single-channel processing capacity,which can realize the low-cost manufacturing of industrial-scale devices.In order to enhance the gas-liquid mass transfer process,this paper explores the gas-liquid mass transfer characteristics of the PA-TMC and its role as a distributor of high-shear mixer,so as to provide new equipment for the enhancement of the gas-liquid mass transfer process.Firstly,the gas-liquid mass transfer performance of PA-TMC was investigated.The effects of different structure parameters and operating parameters on the volumetric mass transfer coefficient(k _La),the oxygen efficiency(φ)and the mass transfer amount per unit energy(ε)of PA-TMC were investigated by sodium sulfite oxidation.The two-phase flow process in the annular space was studied by CFD simulation method,and the two-phase flow pattern in the annular space was monitored by CCD imaging technology,and the flow,bubble dispersion and coalescence laws were obtained to better understand the mass transfer laws.The results show that k _La andφincrease monotonously with the decrease of pore size,the increase of the pore number in a single row,the decrease of the row number,the decrease of the annular size,the increase of helical coil turn,the decrease of the annular length,the increase of the two-phase flow rate and the decrease of the surface tension.Theεincreases monotonously with the decrease of pore size,the increase of the pore number in a single row,the decrease of the row number,the decrease of helical coil turn,the decrease of the annular length,the increase of the gas-phase flow rate,the decrease of liquid-phase flow rate and the decrease of surface tension.Theεchanges little as the decrease of the annular size.The turbulent kinetic energy increases with the decrease of pore size and gas phase size by CFD and CCD.The turbulent kinetic energy increases with the decrease of the row number,the decrease of the annular size,the decrease of the annular length.The strain rate and shear rate increases with the increase of helical coil turn,the increase of the two-phase flow rate and the decrease of the surface tension.In addition,the Sherwood number was correlated with the investigated parameters can fit well with the experimental data with the average deviation of 7.21%,which can guiding the design of PA-TMC in gas-liquid mass transfer process.Secondly,the PA-TMC as distributor enhanced the gas-liquid mass transfer performance of the high shear mixer.In the same way,sodium sulfite oxidation method was used to explore the influence of different structural parameters and operating parameters on the volumetric mass transfer coefficient(k _La*)and the oxygen efficiency(φ*).The enhanced mass transfer performance is better,L~*=8 mm is the optimal value.The k _La*increases with the decrease of pore size,the increase of the pore number in a single row,the decrease of the row number,the increase of the gas-phase flow rate,the increase of liquid-phase flow rate,the the decrease of the surface tension and the increase of the rotor linear velocity.Theφ*decreases with the gas-phase flow rate,other laws are the same as the laws of k _La*.The results show that:PA-TMC has excellent gas-liquid mass transfer.At the same time,it can be used as a distributor to enhance the gas-liquid mass transfer performance of the high-shear mixer,so it has a good industrial application prospect.