【作者】 徐怀东；

【导师】 肖泽仪；

【作者基本信息】 四川大学 ， 化工过程机械， 2003， 硕士

【摘要】 渗透蒸发是近十多年膜分离技术研究最活跃的一个领域，从膜材料、膜过程机理到工程应用都得到迅速发展。渗透蒸发膜分离过程用于均相液体混合物的分离时，对采用传统手段难以处理的恒沸物、近沸点物和共沸物等体系具有特别的优势。本研究中，采用实验室自制的新型硅橡胶复合膜构造了膜生物反应器系统并用于连续发酵制造乙醇，对模型乙醇-水溶液和实际发酵液的分离性能、反应器系统乙醇连续发酵操作参数的控制、操作参数对膜的分离性能及膜持续运行的稳定性等进行了实验研究和分析。本论文分为以下三个部分： 首先，综述了膜分离及渗透蒸发技术的现况、前景和应用；介绍了膜渗透蒸发技术的基本理论及特点。在综合分析国内外发展趋势的基础上，提出本论文的立论依据及研究方案。 然后，具体针对渗透蒸发膜及渗透蒸发过程进行理论论述，主要介绍了膜的结构、选材、种类、制造及渗透蒸发膜器，接着，对影响膜分离性能的主要参数进行了逐一论述，并对渗透蒸发过程模型进行了探讨。 最后，我们对新型硅橡胶膜反应器运用于连续发酵制备乙醇的动力学过程及膜渗透蒸发性能进行研究。首先分别对新型硅橡胶复合膜在酒精溶液及发酵液中的分离性能进行对比测试，实验结果发现，发酵液中的酵母细胞没有造成膜污染或膜堵塞，且在发酵液中膜仍能保持较稳定渗透蒸发性能。经过多次的间歇发酵实验，我们初步掌握了酵母细胞的发酵特性，并开始进行连续发酵实验。在25℃的条件下，维持葡萄糖浓度1009/L，发酵初始体积2L，采用低速循环泵，成功使整个连续发酵过程维持达到461 .sh，渗透通量大致为500一800g/mZ·h，分离因子为5~8.5，过程中酵母细胞及乙醇浓度波动较小，实现了稳定的连续发酵生产，取得了突破性的进展。更多还原

【Abstract】 The membrane separation technology has been achieving the rapid progress for the near decades. As one of the newest developments on membrane separation, pervaporation is a promising technique for the separation of liquid mixtures, such as azeotropic and isomeric mixtures, which are difficult or impossible to separate by conventional methods. The paper has mainly studied the pervaporation performance of a novel silicone rubber compound membrane in the concoctive aqueous ethanol solution and the actual fermentation broth with a membrane bioreactor system (MBR), and how to control the operation parameters of continuous fermentation, and their influence on the membrane separation performance. This paper consists of the following three parts:Firstly, a summarized review was done for the present situation, the prospect and the application about the membrane separation and particularly pervaporation technology. The elementary theory and features about the pervaporation technology was introduced. On the basis of this review, a research proposal was presented.Secondly, in accordance with the setup of the MBR and the features of the composite silicone rubber membrane, a principal theoretical analysis was carried out for the pervaporation process. Some details on the membrane materials, structuresand forming techniques, as well as the membrane bioreactor were analyzed. Then, effects of some process parameters on the membrane separation performance was discussed.Finally, for feasibility of application of the new silicone rubber membrane reactor system to the continuous fermentation for ethanol production, the fermentation kinetics and the mass transfer behaviors of the membrane in the MBR were investigated experimentally. The control test for the concoctive aqueous ethanol solution and the actual fermentation broth was carried out in the MBR system. The experimental result showed that, for the actual fermentation broth, the yeast cell did not cause fouling or other performance declines with the membrane.Through the serial batch fermentation experiments, the microbial features suitable for the ethanol continuous fermentation with the MBR has been realized initially, and then the continuous fermentation experiment was carried out. Under the fermentation temperature of 25 ℃, with the initial glucose concentration of l00g/L, the initial inoculation concentration of the microbe Ig/L, the initial volume of 2L, and the properly low circulating flow rate of the broth, a long-term continuous fermentation process was achieved for 461.5h. During the continuous fermentation process, the composite silicone rubber membrane exhibited an excellent performance with permeating flux of 500 ~ 800 and separation factor of 5 ~ 8.5. In the process the cellular concentration and the ethanol concentration fluctuated lightly without obvious inferior effects on the continuous fermentation.更多还原