以PEI超滤膜为支撑层,PDMS为复合层,制备PDMS/PEI渗透汽化FCC汽油脱硫复合膜.由于实际汽油组成复杂,根据汽油中形态硫的分布情况,实验选择噻吩、2-甲基噻吩、2,5-二甲基噻吩、乙硫醚、丁硫醇5种典型的形态硫模拟实际汽油体系,考察不同形态硫对膜分离性能的影响.同时,考察了不同料液温度对渗透通量和富硫因子的影响.结合溶解度参数理论,研究了5种形态硫与膜的亲和力,亲和力的大小会影响不同形态硫在膜内的溶解和扩散速率.实验结果表明,在同一操作条件下,5种形态硫的渗透分通量和富硫因子大小顺序为:噻吩〉2-甲基噻吩〉2,5-二甲基噻吩〉正丁硫醇〉正丁硫醚;溶解度参数结果能够很好的解释膜对不同形态硫的选择性,所得结果为渗透汽化技术在汽油脱硫领域的应用提供数据支持.
Crosslinked PDMS/PEI composite membranes were prepared for gasoline sweetening by using PEI UF membrane as the microporous supporting layer and PDMS as the composite membrane.As real gasoline is a rather complex mixture,n-heptane was selected to stand for gasoline,while thiophene,2-methyl thiophene,2,5-dimethyl thiophene,n-butyl mercaptan and n-butyl sulfide were chosen as the representative organic sulfurs according to the sulfur distribution of gasoline.Meanwhile,the effects of feed temperature on the separation efficiency and permeation flux were investigated experimentally.By the study and analysis of solubility parameter theory,the interaction intensity between membrane material and typical sulfur species was investigated,and the difference of affinity can reflect the dissolution and diffusion rate difference between sulfur and hydrocarbon species when membrane process was conducted.The results showed that partial flux and enrichment factor of organic sulfur had the order: thiophene 〉2-methyl thiophene〉2,5-dimethyl thiophene〉n-butyl mercaptan〉n-butyl sulfide.The theoretical results show good agreement with the experimental results.All these studies will provide insight of the application of pervaporation technology in the field of sulfur removal from gasoline.