特殊精馏分离碳酸二甲酯—甲醇共沸物的工艺优化与控制策略

发布时间：2018-06-18 09:41

本文选题：碳酸二甲酯 + 甲醇　；参考：《青岛科技大学》2017年硕士论文

【摘要】：碳酸二甲酯(DMC)-甲醇常压下形成共沸物,采用普通精馏工艺不能得到高纯度产品。本文利用Aspen Plus和Aspen Plus Dynamics软件,采用变压精馏和隔壁塔萃取精馏的方法对DMC-甲醇共沸物系实现有效分离。对于变压精馏,以年度总费用(TAC)最小为目标进行经济优化,确定无热集成、部分热集成和完全热集成工艺的最小TAC分别为323,892.509$/y、259,093.925$/y、248,353.238$/y。针对不同热集成工艺中,低压塔温度分布均匀,灵敏板选择困难的问题,给出了一种简单有效的导斜率判据。在此基础上,研究了低压塔不同灵敏板对不同热集成工艺动态特性的影响。动态分析结果表明:组成-温度串级控制策略可以有效的处理无热集成、部分热集成工艺的进料流量与组成扰动。无热集成工艺的最佳温度控制板为第31块或30块板,而部分热集成工艺的最佳温度控制板为第31块或10块板。对于完全热集成工艺,低压塔第29块塔板作为灵敏板的压力-补偿温度控制结构,使两塔产品的稳态余差较小,可以处理±20%的进料流量和组成扰动,实现稳健的动态控制。对于隔壁塔萃取精馏(EDWC),基于常规萃取精馏工艺的最优参数,利用三塔模型进行序贯迭代法优化,对应的最小TAC为189,944.75$/y。在动态控制系统中,通过导斜率判据选择出主塔的温度控制板,并研究了温度控制板与控制结构的动态可控性关系。结果表明:当主塔的灵敏板为第12块塔板时,带气相分配比的控制结构能有效处理进料扰动。而当灵敏板为第5块塔板时,无气相分配比控制策略也能紧紧维持产品的纯度。由于调节气相分配比在实际工业生产中极为困难,因此选择主塔灵敏板为第5块塔板的无气相分配比控制结构为EDWC的最佳控制方案。
[Abstract]:The azeotrope is formed under normal pressure of two methyl carbonate (DMC) - methanol, and the high purity product can not be obtained by ordinary distillation. This paper uses Aspen Plus and Aspen Plus Dynamics software to achieve effective separation of DMC- methanol azeotrope system by pressure variable distillation and extractive distillation with wall column. For variable pressure distillation, the annual total cost (TAC) is minimal. In order to optimize the economy and determine the non thermal integration, the minimum TAC of the partial heat integration and the complete thermal integration process is 323892.509$/y, 259093.925$/y, and 248353.238$/y., respectively, for the problem of the uniform temperature distribution of the low pressure tower and the difficulty of the selection of the sensitive plate in the different heat integration processes. On the basis of this, the influence of different sensitive plates on the dynamic characteristics of different heat integration processes is studied. The dynamic analysis shows that the composition temperature cascade control strategy can effectively handle the heat free integration, the feed flow and the composition disturbance of the partial heat integration process. The optimum temperature control plate for the heat integrated process is thirty-first or 30 plates. The optimum temperature control plate for the integrated heat transfer process is thirty-first or 10 plates. For the complete thermal integration process, the pressure compensation temperature control structure of the twenty-ninth pylon of the low pressure tower is used as the pressure compensation temperature control structure for the sensitive plate, which makes the steady-state residual difference of the two tower products less, and can handle the feed flow rate and the composition disturbance of 20%, so as to achieve robust dynamic control. EDWC, based on the optimal parameters of the conventional extractive distillation process, the three tower model is used to optimize the sequential iterative method. The corresponding minimum TAC is 189944.75$/y. in the dynamic control system. The temperature control plate of the main tower is selected by the guide slope criterion, and the dynamic controllability relationship between the temperature control plate and the control structure is studied. Ming: when the sensitive plate of the main tower is twelfth plates, the control structure with the gas phase ratio can effectively handle the feed disturbance. When the sensitive plate is the fifth plate, the gas distribution ratio control strategy can also maintain the purity of the product tightly. Because it is extremely difficult to adjust the gas phase distribution ratio in the actual industrial production, the main tower sensitive plate is chosen. The optimum control scheme for the fifth trays is EDWC without gas phase distribution ratio.
【学位授予单位】：青岛科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ028.31

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