【作者】 吴松海；

【导师】 张凤宝；

【作者基本信息】 天津大学 ， 化学工程， 2007， 博士

【摘要】 乙酸-水体系的传统分离过程存在效率低、能耗大、成本高等缺点,本文将磁场处理技术引入乙酸-水体系的分离过程,以寻找能提高生产效率,降低能耗的分离方法,同时为建立磁场强化分离理论体系奠定必要的基础。主要研究内容如下:(1)在磁感应强度分别为0.165T、0.240 T、0.310 T和0.515 T的磁场作用下,测定了乙酸、乙酸乙酯和水的粘度、表面张力,并进行了数据回归。(2)在上述磁场作用下,分别对乙酸-水二元体系气液相平衡和乙酸-乙酸乙酯-水三元体系液液相平衡进行了研究。结果表明:外加磁场会对体系的气液和液液相平衡产生影响,总体上呈正效应,即外加磁场提高了体系的平衡常数,有利于体系的分离。但是,磁场对体系的影响并不呈简单的线性关系,磁感应强度和溶液浓度不同,磁场对气液相平衡和液液相平衡的影响也有所不同。论文同时将缔合理论引入乙酸的相平衡计算中,选用Wilson和NRTL方程对气液平衡数据进行了关联,选用NRTL方程对液液平衡数据进行了关联,并提出了磁场对乙酸-水体系气液和液液相平衡的影响因子。(3)为验证磁场对乙酸-水体系分离效果的影响,在上述磁场作用下,向乙酸-水体系添加共沸剂(乙酸乙酯)进行了共沸精馏实验。结果表明:外加磁场有助于体系的精馏分离,随着磁感应强度的增大,磁场对乙酸-水体系精馏的影响程度提高,但磁感应强度对体系的影响有一个极限值。在实验范围内,乙酸的含量最多提高4.42%,收率提高1.44%。(4)通过乙酸-水体系的吸光度和核磁共振的测试和分析,对磁场影响气液和液液平衡及精馏分离效果的机理进行了探讨,认为磁场是通过影响体系中的氢键来影响体系的物理性质和相平衡性质从而影响分离效果的,并对实验结果进行了合理的解释。(5)以外力场下的热力学模型为基础,构建了磁场作用下的相平衡热力学模型,以对不同体系的气液和液液平衡作出预测,并为进一步研究磁场对相平衡提供有益借鉴。更多还原

【Abstract】 Traditional distillation process of acetic acid-water system had the disadvantages of great energy consumption, low efficiency and high operation costs. In order to improve production efficiency and reduce energy consumption, the magnetic distillation was employed. At the same time, a solid foundation for the theory of separation under the magnetic field was established. The main works were as follows:(1) Viscosity and surface tension of water, acetic acid and ethyl acetate were measured and regressed under the different magnetic induction intensities which were 0.165T, 0.240T, 0.36T and 0.55T.(2)The vapor-liquid equilibrium (VLE) of acetic acid-water system and the liquid-liquid equilibrium (LLE) of acetic acid- ethyl acetate-water system were studied under the magnetic field mentioned above. The results showed: the applied magnetic field had a positive effect on VLE and LLE of system, namely the magnetic field could improve the equilibrium constant and be helpful to separation of acetic acid-water system. However, the relationship between the applied magnetic field and the equilibrium constant was not simply linear in the acetic acid-water system. By different magnetic induction intensity and different solution density, effects of magnetic field on VLE and LLE were different to some extent too. In present study, the associating theory was also combined in calculating of acetic acid phase equilibrium, and Wilson and NRTL equation were used to correlate the VLE data while NRTL equation was used to correlate the LLE data. Finally, the effect factor of magnetic field to the VLE and LLE of acetic acid-water was proposed.(3)In order to test the magnetic effects on the acetic acid aqueous solution separation, an azeotropic distillation experiment was conducted with adding the reagent (ethyl acetate). The results showed that the acetic-water system separation benefited by using magnetic field, and with the increase of the magnetic induction intensity, the effects of the magnetic field on acetic acid system distillation raise, but the effects had optimal value. In the experiment, the acetic acid content and yield rate could increase by 4.42% and 1.44% at most.(4) By means of the luminosity and 1H NMR of the acetic acid-water system, the separation mechanism of the VLE, LLE and distillation of the system under the magnetic field was discussed. It was believed that magnetic field could affect the physical and phase equilibrium properties in the system by changing the hydrogen bond and thus achieving the separate efficiency, and there was a rational explanation to the experimental results.(5) On the basis of thermodynamic model in the external force field, the phase equilibrium model was built and used to predict the performance of VLE and LLE of different systems under the magnetic field. It also established a foundation for further study on phase equilibrium under the magnetic field in the future.更多还原