新型气隙式膜蒸馏组件脱盐过程

利用基于聚丙烯中空纤维膜和聚丙烯中空纤维换热管的新型能量回收式膜组件(AGMD-HF),以70 g·L^-1的氯化钠溶液为研究对象,考察了膜组件长度和膜孔径大小对膜组件脱盐性能的影响。为直接衡量操作条件、组件参数以及温差、浓差极化现象对传质系数的影响,引入总传质系数,并研究进料温度和膜孔径对总传质系数的影响。实验结果表明,总传质系数随着温度的升高、膜孔径的增大而增大,提高膜孔径可有效提高总传质系数,同时可有效提高通量和造水比。通量随组件长度的增大而减小,而造水比增大,因此在应用过程中可综合考虑通量和造水比以便选择合适的组件长度。

New air gap membrane distillation module for desalination

A new air gap membrane distillation module based on hollow fiber with energy recovery was developed for desalination using 70 g·L^-1 NaCl solution as the feed. The effects of membrane module length and membrane pore size were investigated. For measuring directly the effects of operating conditions, membrane module properties, and temperature and concentration polarization on the mass transfer coefficient, the total mass transfer coefficient was introduced. The effects of membrane pore size, feeding temperature and feeding flow rate were studied. The results showed that the total mass transfer coefficient increased with the increase of membrane pore size and feeding temperature. The membrane flux and gained-out put ratio were increased effectively with increasing membrane pore size. Since increasing membrane module length would reduce the membrane flux while enhance the gained-out put ratio, the membrane flux and gained-out put ratio should be considered comprehensively for selection of the appropriate membrane module length in the application process.