PDMS复合膜薄层流动膜组件中的渗透蒸发传质动力学  

Mass Transfer Kinetics of Pervaporation in A Thin-layer-flow Module with A Composite PDMS Membrane

作　　者：肖泽仪[1] 汤明[1] 黄卫星[1] 石尔[1] 李东怀[1] 胡世文[1] 

机构地区：[1]四川大学化学工程学院,四川成都610065

出　　处：《四川大学学报（工程科学版）》2005年第6期46-51,共6页Journal of Sichuan University (Engineering Science Edition)

基　　金：国家自然科学基金资助项目(20276030)

摘　　要：用自制的高性能矩形平板PDMS复合膜构造了薄层流动水力学结构的渗透蒸发膜组件,并进行了乙醇溶液的渗透蒸发传质动力学研究。实验得到了很好的渗透通量与浓度推动力之间的动力学关系。根据膜渗透蒸发的串联阻力概念,把液相边界层传质的Sherwood模型计算值与实验测量的总传质系数相结合,得出了渗透蒸发的膜内传质系数。分析表明,在料液温度25℃时,膜内传质阻力对渗透蒸发传质总阻力的贡献超过70%,说明膜内传质阻力是整个渗透蒸发过程的控制因素。对不同流动状态和不同温度下的传质动力学行为进行了实验测量和分析,结果显示,矩形平板PDMS复合膜与薄层流动膜组件的结合优于我们原来研究过的圆形膜及膜器,可以充分发挥膜的高性能。这一结果对PDMS复合膜和膜组件构形及其渗透蒸发过程的设计和运行具有重要意义。A rectangular plate-frame module for pervaporation was configured with a composite PDMS membrane. The module had a hydraulic structure of one-dimensional and thin-layer flow. The pervapomtion kinetics for aqueous ethanol with the module was studied. The experimental results showed a linear relationships between the ethanol permeation fluxes and the concentration. According to the resistance-in-series concept for the membrane transport, and by combining the experimental measurements and calculations based upon Sherwood model, the transport coefficients were obtained. The results indicated that, when the feed temperature was 25℃, more than 70 percent of the overall mass transfer resistance was from diffusion in membrane. So the mass transfer resistance in membrane was still dominant for the module. The transport behaviors in different temperatures and different flow status were explored similarly. It was proved that the new module was superior to the circular modules that we investigated previously, on highlighting performances of the prepared composite PDMS membrane. This study provided some useful knowledge with the composite PDMS membrane and the modules, as well as the process design and operation of pervaporation.

关 键 词：PDMS复合膜 渗透蒸发 平板膜组件 传质动力学 乙醇 

分 类 号：TQ028[化学工程]