渗透汽化和蒸汽渗透膜分离过程的对比实验研究.pdf

C032 渗透汽化和蒸汽渗透膜分离过程的对比实验研究 马明林 王保国 （清华大学化学工程系，北京100084） 摘 要 渗透汽化 PV ）和蒸汽渗透 VP ）都是利用膜对混合物中不同组分的溶解度与扩散系数 不同来实现分离的膜分离方法。两种过程的传质推动力都是组分在膜中的化学位梯度。由于它们 所特有的低能耗，低费用等优点,近年来无论是在理论研究还是技术革新上都受到了普遍的关注。 为了从热力学和传质角度研究PV 和VP 膜分离过程，本文设计了在线测量混合气体浓度，可以 在同一渗透池中同时进行PV 和VP 分离过程的实验装置。使用PVA/PAN 复合膜进行水/ 乙醇混 合物以及水/异丙醇混合物的PV 和VP 渗透实验，对两个过程中渗透通量随浓度变化情况进行了 分析和比较。实验结果和理论分析表明：溶液的PV 过程和与之呈相平衡的蒸汽相的VP 过程在 一定温度范围内，当原料溶液中水含量较低的情况下具有同一性，其传质遵从溶解扩散机理。实 验还表明：当原料溶液中水含量较高时，PV 过程中膜溶胀现象较为严重，而 VP 过程对温度更 加敏感。 关键词 渗透汽化，蒸汽渗透，溶解扩散模型，PVA/PAN 复合膜 中图分类号 TQ 028.8 文献标识码 A A DIRECT COMPARISON OF PERVAPORATION WITH VAPOR PERMEATION MEMBRANE SEPARATION MA Minglin and WANG Baoguo ( Depa rtment of Chemical Engineering, Tsinghua university, Beijing, 100084 China) Abstract A pervaporation(PV) or vapor permeation(VP) process has been proofed to be effective for removing the pollutant from industrial emission, dehydrating organic solvent and separating organic/organic mixture. Owing to the feed state, researchers generally classify them as different membrane separation processes, and engineers design a separation with different method in a commercial application. However, both pervaporation and vapor permeation can be analyzed based on solution-diffusion mechanism, and our previous study also showed the identical permeation behavior, when extraction of chloroform from air and dilute aqueous has been performed by vapor permeation and pervaporation. As a matter of fact, if observation were based on the viewpoint inside a polymer matrix, diffusion behavior of molecules in both operations would take on the identical nature. In order to obtain a direct experimental evidence, a specified design instrument has been developed in thi