用于海水淡化的渗透汽化膜组件设计及实验研究

发布时间：2018-10-18 19:44

【摘要】：随着我国经济的快速发展,淡水资源的过度开发利用和水体污染的日益加剧,导致我国水资源缺乏问题愈加突出。为了缓解这种紧张的局势,从丰富的海水资源中获取淡水的技术受到人们广泛的关注与研究。传统的脱盐技术由于自身缺陷使得他们在海水淡化领域的进一步发展受到了限制。渗透汽化作为新发展起来的脱盐技术,综合了热法和膜法两种脱盐技术的诸多优点,是海水淡化领域极具潜力的技术。经过多年的研究,渗透汽化膜具备高通量和高截留率的特点,但是渗透汽化脱盐的实际应用并不多见。因此,本论文设计一种新型的板框式膜组件,为渗透汽化脱盐的工业应用打下理论基础并积累经验。对膜组件中所使用的磺化非均质膜的性能进行了表征与测试,探索了不同温度、浓度及真空压力等操作参数对渗透汽化通量的影响。用抽滤预处理后的海水进行长期渗透汽化实验,并对表面污染物的成分进行分析,发现膜表面的主要污染物是碳酸盐和硫酸盐。针对膜污染进行清洗探究,以不同种类的酸作为膜清洗试剂,发现盐酸(pH=2)清洗能够使膜通量得到最大程度的恢复。针对平板式膜组件内部的不良流动状态,采用FLUENT流体模拟软件对实验设计的板框流道结构进行模拟分析与改进,最终得到了进水分布较好的流道结构,并通过实验测量的方法对模拟结果进行了验证,所得结论保持一致。根据模拟结果和实际情况的要求,对整个膜组件的结构进行了设计,采用3D打印技术制备了具有复杂流道结构的膜组件。以该膜组件为核心搭建了一套渗透汽化装置系统,对装置系统的处理能力进行评估,在装置运行稳定状态下对海水进行处理,其产水量可达80L·d-1。
[Abstract]:With the rapid development of China's economy, the over-exploitation of freshwater resources and the worsening of water pollution, the shortage of water resources in China has become more and more prominent. In order to alleviate this tense situation, the technology of obtaining fresh water from rich sea water resources has received extensive attention and research. Their further development in desalination field is restricted by traditional desalination technology due to its own defects. As a newly developed desalination technology, osmotic vaporization combines many advantages of thermal desalination and membrane desalination, and is a potential technology in the field of seawater desalination. After many years of research, pervaporation membrane has the characteristics of high throughput and high retention, but the practical application of osmotic vaporization desalination is rare. Therefore, this paper designs a new type of plate and frame membrane module, which lays a theoretical foundation and accumulates experience for industrial application of pervaporation desalination. The properties of sulfonated heterogeneous membranes used in membrane modules were characterized and tested. The effects of operating parameters such as temperature, concentration and vacuum pressure on pervaporation flux were investigated. A long-term pervaporation experiment was carried out in seawater pretreated by filtration and the composition of surface pollutants was analyzed. It was found that the main pollutants on membrane surface were carbonate and sulfate. The cleaning of membrane fouling was carried out and different kinds of acid were used as membrane cleaning reagents. It was found that hydrochloric acid (pH=2) cleaning could make membrane flux recover as much as possible. In view of the bad flow state in the flat membrane assembly, the flow channel structure of the plate and frame was simulated and improved by using FLUENT fluid simulation software. Finally, the flow channel structure with better distribution of inlet water was obtained. The simulation results are verified by the method of experimental measurement, and the results are consistent. According to the simulation results and the requirements of the actual situation, the structure of the whole membrane assembly is designed, and the membrane assembly with complex flow channel structure is fabricated by 3D printing technology. Based on the membrane module, a pervaporation equipment system was set up. The capacity of the system was evaluated, and the seawater was treated under the condition of steady operation. The water yield was up to 80L d ~ (-1).
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ051.893

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