Suga Yuki, Takagi Ryousuke, Matsuyama Hideto
Research Center for Membrane and Film Technology, Department of Chemical Science and Engineering, Kobe University, Nada, Kobe 657-8501, Japan.
AsahiKASEI Corporation, Chiyoda-ku, Tokyo 100-0006, Japan.
Membranes (Basel). 2021 Mar 31;11(4):252. doi: 10.3390/membranes11040252.
Membrane distillation (MD) is a technology that can treat feed solutions with higher osmotic pressure, as well as produce high-purity water. However, the water production cost of the MD process is expensive. In this study, to decrease the water production cost, we attempted to evaluate the effect of membrane characteristics on the long-term stability of a vacuum MD (VMD) system. We fabricated four different types of polyvinylidene difluoride hollow fiber membranes, and operated a VMD system with 3.5 wt% NaCl aqueous solution at 65 °C as a feed under 11 kPa of air gap pressure. Consequently, in the proposed VMD system, it is found that the liquid entry pressure (LEP) is the most important factor. When LEP was higher than 0.37 MPa, the pilot-scale module was very stable for long-term operations, and the vapor flux was approximately 19.3 kg/m·h with a total salt retention factor of over 99.9% during the 300-h operation.
膜蒸馏（MD）是一种能够处理具有较高渗透压的进料溶液并生产高纯水的技术。然而，MD工艺的产水成本很高。在本研究中，为了降低产水成本，我们试图评估膜特性对真空膜蒸馏（VMD）系统长期稳定性的影响。我们制备了四种不同类型的聚偏氟乙烯中空纤维膜，并在气隙压力为11 kPa的条件下，以65℃的3.5 wt% NaCl水溶液作为进料运行VMD系统。结果发现，在所提出的VMD系统中，液体进入压力（LEP）是最重要的因素。当LEP高于0.37 MPa时，中试规模的模块在长期运行中非常稳定，在300小时的运行过程中，蒸汽通量约为19.3 kg/m·h，总盐截留率超过99.9%。
