【作者】 王平； 刘晶； 秦英杰； 刘立强； 崔东胜；

【Author】 Wang Ping~1 LiuJing~1 Qin Yingjie~(1,2) Liu Liqiang~2 Cui Dongsheng~2 (1.the School of Chemical Engineering and Technology,Tianjin University,Tianjin 300072,China; 2.Chembrane Engineering and Technology,Inc.,Tianjin 300308,China)

【机构】 天津大学化工学院； 天津凯铂能膜工程技术有限公司；

【摘要】 用多效膜蒸馏技术对某钢铁厂反渗透浓水进行深度浓缩。着重研究了浓缩过程中膜通量、造水比和蒸出淡水水质的变化。结果表明,该过程可将废水浓缩10倍以上,淡水回收率大于90%。当以97度热水为热源时,造水比为6.2～10.5,膜通量为3.0～6.5 L·m^-2·h^-1。蒸出的淡水电导率在3.0～7.8μs·cm^-1之间,COD_cr值小于20 mg·L^-1,可回用于生产。多效膜蒸馏法浓缩后的浓水可进一步用常规蒸发-结晶设备得到固体盐,实现废水完全回用和零排放。通过两个月的连续操作,发现膜组件的操作性能保持稳定。更多还原

【Abstract】 In the present study,multi-effect membrane distillation（MEMD） based on air gap membrane distillation（AGMD） module with function of internal heat recovery has been developed to deep concentrate the RO brine drained from an iron and steel plant.This kind of MEMD process combines the advantages of MD process and conventional MSF process,avoids the disadvantages of MSF such as evacu- ation operation,and can provide a high perform ratio（PR） value.The water vapor flux（J）,perform ratio （PR） and permeate water quality are the most important indicators for evaluation of MEMD modules. MEMD operation was carried out to deep concentrate the RO brine with water of 97℃as the heating resource. The experimental results show that the reverse osmosis brine could be concentrated by more than 10 times and the freshwater recovery was more than 90%.Under optimized operational conditions,the value of J decreased from 6.5 to 3.0 L·m^-2.h^-1;and the value of PR decreased from 10.5 to 6.2. The value of PR is the highest value experimentally obtained for MD process.The electrical conductivity of the permeate water was between 3.0 and 7.8μs cm^-1,and the COD_cr was under 20 mg·L^-1.The permeate water could be reused directly.The brine from MEMD can be further treated by the conventional evaporation - crystallization device to get solid salt waste.A complete treatment of the wastewater and zero emission could be realized by this method.In a long - term stability test lasting for two months,the MEMD module kept in good condition.All these results demonstrated that MEMD process can be efficiently used to deep concentrate the RO brine drained from iron and steel plants.更多还原