Micromixing And Liquid–Liquid Mass Transfer&Reaction Selectivity Performance In A Micropore-Jet Capillary Reactor

Microreaction technology has been widely used in the field of chemical process intensification,especially for fast and complicated competitive reaction systems.For liquid-liquid biphase fast competitive reactions,the reaction process is controlled by mass transfer property,which significantly affects the reaction conversion and yield.However,due to the low throughput of single microchannel and complex fluid distributing structure,the cost of devices has risen.In this paper,a new type of micropore-jet capillary microreactor（MJCM）was developed by combing the advantages of cross-flow T-mixer and shell&tube heat exchanger.In order to meet the requirements of liquid-liquid biphase fast transfer and reaction,one fluid jets into the capillary through the micropore and mix with the other fluid efficiently.The micromixing property,liquid-liquid mass transfer property and reaction selectivity of single-tube MJCM were systematically investigated in this paper.Firstly,the micromixing property of MJCM with different structural and operating parameters were studied by the Villermaux/Dushman System and CFD simulations,which was characterized by segregation index X_s.Both results indicate that X_s increases with the increase of pore size and inlet H⁺concentration,while decreases with the increase of flow rate.X_s first increases dramatically then stays stable as the capillary becomes longer.X_s first increases then decreases as flux ratio increases,while the increase of capillary diameter makes X_s first increase then remain constant.The micromixing time was estimated by incorporation model and the optimal micromixing time could reach 10^-3 s in MJCM.The comparison with other reactors shows that the MJCM is an efficient and high-throughput microchannel to meet the industrial applications with excellent micromixing performance.Secondly,liquid-liquid biphase mass transfer property and reaction selectivity were studied under different experimental conditions and structure parameters,adopting respectively the water-benzoic acid-kerosene system and the water-Na OH-toluene-benzoic acid-ethyl chloroacetate system.Meanwhile,the correlation of Sh and X_s were obtained.The results indicate that the mass transfer efficiency（E）decreases,the overall volumetric mass transfer coefficient（K_La）increases,while reaction selectivity index（X_s）first decreases then increases,as the flow rates of two immiscible liquid phases rise.Both liquid–liquid mass transfer and reaction selectivity weaken under larger pore size.Increasing the capillary length results in the increase of E and X_sbut decrease of K_La.Both E and K_La decrease while X_s increases with the increase of capillary inner diameter.The volumetric flux ratio of the aqueous phase to the organic phase affects E and K_La in different tendency.Moderate rise of temperature can improve the reaction selectivity.Adding the surfactant can decrease mass transfer property and reaction selectivity.Comparing with other liquid-liquid mass transfer devices,MJCM shows excellent performance on mass transfer property and reaction selectivity,with promising applications in industrial productions to intensify liquid-liquid mass transfer and reaction processes.