PVDF疏水膜润湿进程控制

发布时间：2018-02-09 11:50

本文关键词： 膜蒸馏膜润湿膜孔干燥临界润湿深度气体吹扫　出处：《天津工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着水资源污染状况的日益加剧,疏水膜分离技术的应用越来越广泛。但与此同时,疏水膜在使用过程中存在的膜孔干燥问题不容忽视。为了解决疏水膜的膜孔干燥问题,本文首先借鉴本课题组前期的科研成果,进一步研究了疏水膜的临界润湿深度,并通过本文设计的VMD-清洗实验,在室温条件下实现了疏水膜分离过程的持续运行。其次,提出了一种采用室温空气吹扫干燥疏水膜的方法,并验证了气体在吹扫过程中的作用原理。根据本课题组前期的研究成果,进一步研究发现实验所用的疏水性聚偏氟乙烯中空纤维膜的临界润湿深度为一具体范围19.5±0.5μm。采用另一种表面活性剂对疏水膜进行分离实验,得到该疏水膜的临界润湿深度值为20.0μm,此深度值在19.5±0.5μm范围内,由此可以确定对于特定的疏水膜材料临界润湿深度值为一个确定值。按照本文设计的自脱水运行方法,通过循环进行VMD-清洗实验,在室温条件下可以实现疏水膜材料的膜孔干燥,从而实现膜分离过程的持续运行。采用室温空气对疏水膜进行吹扫,发现对于实验所用的疏水膜的吹扫干燥方法,存在一个吹扫气体压力限值,此值在0.108MPa与0.144MPa之间,当吹扫气体压力在此范围内,疏水膜表面的水可以被全部排出,从而使疏水膜恢复至干燥状态。通过研究含湿量不同的两种室温气体对疏水膜的吹扫作用原理,可以确定气体在吹扫过程中主要表现为吹扫气体的机械剪切力作用而不是气体载湿干燥作用,与常规加热干燥方法的原理不同。
[Abstract]:With the increasing pollution of water resources, the application of hydrophobic membrane separation technology is becoming more and more extensive, but at the same time, the problem of membrane pore drying in the process of using hydrophobic membrane can not be ignored. In this paper, the critical wetting depth of the hydrophobic membrane is further studied by referring to the previous research results of our group, and the continuous operation of the hydrophobic membrane separation process is realized at room temperature through the VMD-cleaning experiment designed in this paper. A method of using room temperature air to sweep dry hydrophobic film is put forward, and the action principle of gas in the process of blowing is verified. It was found that the critical wetting depth of the hydrophobic polyvinylidene fluoride hollow fiber membrane was 19.5 卤0.5 渭 m. Another surfactant was used to separate the hydrophobic membrane. The critical wetting depth of the hydrophobic film is 20.0 渭 m, which is in the range of 19.5 卤0.5 渭 m. It can be determined that the critical wetting depth of the hydrophobic membrane material is a certain value. According to the self-dewatering operation method designed in this paper, By circulating VMD-cleaning experiment, the membrane hole drying of hydrophobic membrane material can be realized at room temperature, and the continuous operation of membrane separation process can be realized, and the hydrophobic film can be swept by air at room temperature. It is found that there is a limit value of blowing gas pressure between 0.108 MPA and 0.144 MPA for the blowing drying method of the hydrophobic film used in the experiment. When the blowing gas pressure is in this range, the water on the surface of the hydrophobic film can be completely discharged. In order to restore the hydrophobic film to the dry state. By studying the principle of blowing and sweeping the hydrophobic film by two kinds of room temperature gases with different moisture content, It can be concluded that the mechanical shear force of the purging gas is the main mechanism in the process of gas purging rather than the wet drying of the gas, which is different from the principle of the conventional heating drying method.
【学位授予单位】：天津工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ051.893

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