不对称静电场耦合渗透汽化过程

发布时间：2018-03-16 19:29

本文选题：不对称静电场　切入点：电场梯度　出处：《天津工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：渗透汽化是近几十年发展起来的一种节能、环保的新型膜分离技术。它具有分离系数大、能耗低、操作简单等特点,在有机物脱水,水中回收贵重有机物,有机物混合液分离等领域应用前景广泛。此外,其分离作用不受气-液平衡的限制,特别适用于精馏方法难以分离的近沸物和恒沸物。渗透汽化的缺点是渗透通量小,因此提高其渗透通量已成为渗透汽化分离领域的一个重要课题。本文使用商品膜材料,通过在膜池渗透侧和原料侧分别放置针电极和板电极,形成不对称静电场,建立不对称静电场耦合渗透汽化过程体系。极性分子由于受到电场作用,偶极矩产生变化,从而获得一个附加的电场梯度力,使其加速朝着电场强度大的渗透侧迁移。实验主要研究了无水乙醇在渗透汽化过程中,电场强度对渗透通量的影响;设计多个不同面积大小的膜池,考察相同操作条件下单个针电极的作用范围;在渗透侧设置多个针电极,研究针电极数量和组合方式对渗透通量的影响;考察电场因素对膜材料结构的影响,综合使用了 SEM、AFM、XPS、ATR-FTIR和接触角测试仪,对膜材料进行表征。实验结果表明,同等实验条件下,不对称静电场的存在使渗透汽化的渗透通量有相当程度的提高,且提高率随电场强度增加而线性增大;单针电极的作用范围是一定的,超过此范围后电场几乎没有作用;多针电极比单针电极对渗透通量的提高作用更强,但提高率并不与针电极数量成正比;经高压静电场处理后的膜材料本身结构并没有明显变化,电场对膜结构没有影响。
[Abstract]:Pervaporation is a new type of membrane separation technology developed in recent decades, which is energy-saving and environmentally friendly. It has the characteristics of large separation coefficient, low energy consumption, simple operation, dehydration of organic matter and recovery of precious organic matter in water. In addition, the separation effect is not limited by the gas-liquid equilibrium, especially for the near and azeotropic substances which are difficult to be separated by distillation. The disadvantage of pervaporation is that the permeation flux is small. Therefore, increasing the permeation flux has become an important subject in the field of pervaporation separation. In this paper, the asymmetric electrostatic field is formed by placing needle electrode and plate electrode on the permeable side of the membrane cell and the raw material side, respectively. An asymmetric electrostatic-field coupled pervaporation process system is established. The dipole moment of polar molecules is changed due to the effect of electric field, and an additional electric field gradient force is obtained. The experiment mainly studies the effect of the electric field intensity on the permeation flux in the process of pervaporation of anhydrous ethanol. The range of action of a single needle electrode under the same operating conditions was investigated; the influence of the number and combination of needle electrodes on the permeation flux was studied by setting multiple needle electrodes at the permeation side; and the influence of electric field factors on the structure of membrane materials was investigated. The membrane material was characterized by SEMMA-AFMMA-XPSS-ATR-FTIR and contact angle tester. The experimental results show that under the same experimental conditions, the permeation flux of pervaporation can be increased to a certain extent by the existence of asymmetric electrostatic field. And the increasing rate increases linearly with the increase of electric field intensity, the action range of single needle electrode is certain, and the electric field almost has no effect when the electric field exceeds this range, and the increase of permeation flux of multi-needle electrode is stronger than that of single needle electrode. However, the increase rate is not directly proportional to the number of needle electrodes, and the structure of the membrane treated by high voltage electrostatic field has no obvious change, and the electric field has no effect on the membrane structure.
【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】：TQ028.8

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