可旋转式太阳能集热器减压膜蒸馏海水淡化装置的实验研究

发布时间：2018-03-09 13:58

  本文选题：太阳能集热器　切入点：减压膜蒸馏　出处：《武汉纺织大学》2016年硕士论文　论文类型：学位论文

【摘要】：众所周知,淡水资源是人类赖以生存和发展的基础物质之一。然而,随着社会经济以及现代工业的不断发展,淡水资源的短缺已经成为世界性问题。海水淡化作为一种解决淡水资源短缺的重要手段越来越被世界各国所关注。常规的海水淡化是高能耗产业,但在当今石油资源日益枯竭的威胁下,人类不得不寻求一种绿色可持续的海水淡化发展道路。因此,结合可再生能源(如太阳能)等实现海水淡化必将成为解决淡水危机的重要研究方向。膜蒸馏技术(Membrane distillation,MD)是一种将膜技术与热蒸馏过程结合在一起的新型膜分离技术,由于MD不需要将待处理的液体加热到沸点以上,因此所需操作温度更低。将MD过程耦合太阳能集热技术,利用低品位热源作为膜蒸馏的能源驱动,是目前膜蒸馏淡化海水研究的一个新热点,有望成为一种高效廉价的海水脱盐技术。本文首先用恒温电加热水箱作为加热热源,以3.5%的NaCl溶液模拟海水,用疏水性聚丙烯(PP)中空纤维膜进行减压膜蒸馏实验,重点研究不同进料液温度、冷侧真空度、进料液流量以及进料液浓度对膜通量、截留率、淡水电导率等的影响,从而确定影响实验系统的最佳反应条件。实验结果表明,进料液温度和冷侧真空度是影响系统性能的主要因素,其最佳反应条件为:温度70℃;真空度0.095MPa;其中最大膜通量达到10.31kg/(m2·h);聚丙烯(PP)疏水膜表现出了很好的膜分离功能,截留率均大于99.9%,且淡水的电导率可达10μs/cm以下。其次,在减压膜蒸馏小试实验的基础上,设计构建了一种新型可旋转的、以太阳能集热器耦合电加热的减压膜蒸馏海水淡化系统,考察可旋转式太阳能集热装置的集热稳定性,确定其应用于膜蒸馏实验的可行性。最后,以经过预处理的真实海水在该装置下进行实验,考察了一个工作日内太阳能海水淡化装置的工作状态,并对该新型装置下的海水淡化实验过程与结论进行分析,总结运行过程中的缺陷和不足,为将来构建太阳能膜蒸馏海水淡化中试系统提供一定的参考和依据。
[Abstract]:As we all know, freshwater resources are one of the basic materials for human survival and development. However, with the development of social economy and modern industry, The shortage of fresh water resources has become a worldwide problem. As an important means to solve the shortage of fresh water resources, seawater desalination has been paid more and more attention by many countries all over the world. Conventional desalination is a high energy consumption industry. However, under the threat of increasing depletion of petroleum resources, human beings have to seek a green and sustainable way to develop seawater desalination. Seawater desalination with renewable energy (such as solar energy) will become an important research direction to solve the freshwater crisis. Membrane distillation (Membrane distillation) is a new membrane separation technology which combines membrane technology with thermal distillation process. Because MD does not need to heat the liquid to the boiling point, so the operating temperature is lower. The MD process is coupled with solar energy collection technology, and the low-grade heat source is used as the energy source for membrane distillation. At present, membrane distillation desalination is a new research hotspot, which is expected to become an efficient and cheap desalination technology. In this paper, the constant temperature electric heating tank is used as the heating heat source, and the 3.5% NaCl solution is used to simulate the sea water. The experiment of vacuum membrane distillation with hydrophobic polypropylene (PP) hollow fiber membrane was carried out. The effects of different feed temperature, cold side vacuum degree, feed liquid flow rate and feed liquid concentration on membrane flux, rejection rate, fresh water conductivity and so on were studied. The experimental results show that the temperature of feed liquid and the vacuum degree of cold side are the main factors affecting the performance of the system, and the optimum reaction conditions are as follows: temperature 70 鈩，

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