Studies On The Integrated Ceramic Membrane Emulsification Apparatus And Its Applications

Studies on novel functional reactor integrating reactor with membrane processhas been the research hotspot in modern chemical engineering. Inorganic membraneswere widely used in the field for their good material performance. A novel integratedceramic membrane emulsification apparatus including an apparatus of ceramicmembrane emulsification and a stirred slurry reactor was proposed, which is the baseon exploitation of the integrated membrane emulsification reactor. Using theapparatus, monodispersed emulsions and ultrafine particle of SiO2 were prepared inthis thesis.In chapter 2,the feasibility of the integrated ceramic membrane emulsificationapparatus was discussed. To satisfy the requirement of the integration, the membraneemulsification apparatus must be provided with the characteristics of simple structure,convenient operation and easier to scale-up. Furthermore, to control size in themesoscopic range, the method for control size of emulsion using the apparatus shouldbe investigated too. So a simple integrated membrane emulsification apparatus wasfirstly set up, which mostly included a ceramic external membrane element used asmembrane medium and a magnetic stirrer used to supply shearing stress. Isobutanolwas used as the dispersed phase and water was used as the continuous phase, theinterfacial tension between isobutanol and water is very low. The influences ofsurfactant and membrane pore size on the process were studied. The α-Al2O3membranes with pore size of 0.69μm and 0.16μm were used in our experiments. Andthe emulsions with volume mean particle size of 2.50 and 1.76μm were respectivelyprepared by the two membranes. The specific surface area of the two emulsions were3.78 m2·g-1 and 10.8 m2·g-1, which could be used to provide a bigger mass transfersurface in extractive reactor and biphasic reaction. The flux of the membrane withpore size of 0.69μm was 121~131 L·m-2·h-1 and he flux of the membrane with poresize of 0.16μm was 56~62 L·m-2·h-1 under the pressure of 0.06MPa. Compared withthe high speed mixer, the apparatus could provide bigger specific surface area underlower shearing stress.In chapter 3, monodispersed O/W emulsions were prepared by the integratedmembrane emulsification apparatus. Ceramic membrane is a kind of asymmetricalmembrane generally prepared by the method of solid particle sinter, which leads tocoarse pore exist. And so it is difficult to prepare monodispersed emulsion. However, III南京工业大学 博士论文preparation of monodispersed emulsions, especially preparation of monodispersedemulsion with small particle size, is the key and base to use membrane emulsion inthe integrated reactor. Toluene was used as the dispersed phase and water was used asthe continuous phase. And sodium dodecyl sulfate (SDS), a kind of anionic surfactant,was used as emulsifier. ZrO2 membrane with pore size of 0.16μm was used asemulsification medium. The emulsion with particle size of 3.53μm was prepared at1.1 times of the critical emulsification pressure (60kPa), stirring speed of 280rpm andthe temperature of 32℃. The distribution of droplets size is bi-apex distribution andthe range of the distribution (α) is 2.5 for existing coarse pore. By adding 0.6%SPAN80 into the dispersed phase, monodispersed emulsion with 3.60μm wasprepared and its range of distribution was 1.33. The fluxes in the two processes wereboth low, which were about 4~5 L·m-2·h-1. To solve the paradox between the flux anddroplets size in the conventional membrane emulsification, a process includingtwo-stage ceramic membrane emulsification under jet flow was proposed in this work.Monodispersed O/W emulsion can be prepared by the process. The monodispersedemulsion with droplets size of 2.29μm and the range of droplets size distribution of1.205 were obtained. The flux of the ZrO2 membrane with pore size of 0.16μm in thefirst stage was 150 L·m-2·h-1 at a pressure of 0.35MPa, a stirring speed of 280rpm anda temperature of 2...