Study On Preparation Of High Performance Nanoparticles By Impinging Stream Microreactor In Unconfined Space

Compared with conventional materials,nanoparticles have many special properties,such as quantum size effect and surface effect,which make nanoparticles been more widely applied.Direct precipitation method has the advantage of simple technology,low production cost and easy industrial amplification.Because of those advantages,it has become the main method of large-scale preparation of nanoparticles in industry.However,the synthetic process has high requirements for the mixing performance of the reaction system.The mixing performance will directly affect the performance of synthesized nanoparticles and decide the application prospect of reaction equipment.At present,due to the mixing performance of traditional reaction equipment is poor,the performance of synthesized nanoparticles is not desired.Butmicrostructural devices have the advantages of fast mass transfer and perfect mixing performance,therefore,they are widely applied to the industrial synthesis of high-performance nanoparticles.Butusing the microstructural devicesto prepare nanoparticles method mainlyoccurs in the confined space,and the high active nanoparticles are easily accumulated and blocked the channel,which leads to the increase of industrial post-processing cost and in insecurity,thus limiting the application of the microstructural devices in industry.Based on these concerns,this paper aims to using gas collision and gas micro-dispersion to improve the mixing performance of the reaction system.At the same time,a large number of gases are introduced to further strengthen the mixing process for achieving the preparation of high performance nanoparticles.Furthermore,the introduction of large amounts of gas and the transfer of reaction space to the unconfined space can solve the problem of blockage in confined space.The effects of reactant concentration,gas pressure and gas liquid volume flow ratio on the properties of nanoparticles were systematically studied.By controlling the experimental conditions,under the throughput of a reactor is 273.6 g/h,the controllable preparation of highly dispersed zinc oxide nanoparticles with a high specific surface area and a specific surface area of 7nm and a specific surface area of 88.89m2/g and a highly dispersed silica nanoparticle with a dispersion index of 0.85 are realized.Using the parallel competition reaction method,the minimum value of the segmentation factor index Xs of the impinging flow microreactor is 0.008,and the membrane dispersion microreactor reaches the same order of magnitude,which shows that the gas impinging flow microreactor has a good mixing performance.This paper provides an efficient and controllable new method for industrial synthesis of high performance nanoparticles.