卷式纳滤膜的气液两相流清洗特性  

Cleaning characteristics of spiral nanofiltration membrane with gas-liquid two-phase flow process

作　　者：王枢[1] 郭竹洁[1] 孟涛[1] 张兆利[1] 

机构地区：[1]西南交通大学生命科学与工程学院,四川成都610031

出　　处：《化工学报》2011年第6期1587-1592,共6页CIESC Journal

基　　金：国家自然科学基金项目(20706046)~~

摘　　要：引言 膜分离技术在化工、食品、医药、石油、环境等领域已有广泛应用。其中卷式纳滤膜因装填密度大、膜元件更换方便、适用面广等优点，在各行业已大规模进入工业应用，但膜污染问题是制约其发展的主要因素。工业上通常采用化学清洗方法，但清洗时间长，清洗用水和清洗剂消耗量大，同时产生大量清洗废水，且难以保证清洗效果。A novel membrane cleaning apparatus was constructed and used to study the cleaning of 2540-elements（2.5-inch） spiral NF membrane with gas-liquid two-phase flow process.The two-phase flow was formed by mixing the cleaning liquid with compressed air.The effects of cleaning liquid flow rate,air velocity,ratio of gas to liquid,and cleaning time on the rejection rate and flux recovery ratio（FRR）of NF membrane were investigated systematically.The results showed that high FRR of NF membrane was achieved by relatively low cleaning liquid flow rate about 0.1 L·min-1.NF membranes with different active areas had different critical cleaning flow rates.Above the critical flow rate,FRR of NF membrane increased slowly.FRR of NF membrane increased with air velocity.For polyamide composite NF membrane,the upper limit was 14 m·s-1 and higher air velocity would decrease the rejection rate of membrane.FRR of NF membrane was effectively improved when the gas to liquid ratio was from 1000∶1 to 3000∶1.The ratios lower than 1000∶1 or higher than 4000∶1 would decrease FRR.FRR was higher than 95% for cleaning NF membranes in a short 15 min cycle of the two-phase flow process.

关 键 词：膜清洗 卷式纳滤膜 气液两相流 通量恢复率 截留率 气体流速 气液比 

分 类 号：TQ028.8[化学工程]