含低碳醇二元共沸物共沸特性的QSPR模型及其特殊精馏分离策略

发布时间：2018-05-30 20:36

本文选题：共沸物 + QSPR　；参考：《青岛科技大学》2017年硕士论文

【摘要】：本文从热力学分析、过程设计和强化、动态控制三个不同的方面对变压精馏开展研究,提出运用定量构效关系(QSPR,即quantitative structure-property relationship)方法来探究共沸物的共沸特性、热力学性质、变压精馏最佳操作参数以及最佳动态控制结构与共沸物组分分子结构之间的关系。计算了80种含低碳醇二元共沸混合物的组成描述符、拓扑描述符、空间描述符等336种结构参数,应用遗传算法从中优化筛选出密切相关的7种分子描述符,确立了含低碳醇二元共沸物共沸温度和共沸组成的模型。对模型进行了内部及外部验证来检验模型的可靠性,最优共沸温度模型的决定系数(R~2)和交叉验证系数(R~2CV)均在0.90以上,最优共沸组成模型R~2为0.87,R~2CV为0.82。研究表明,本文所建模型的稳定性和预测能力较好。借助Aspen Plus软件内置数据库获取汽液平衡数据,通过定性判断选取了1,2-丙二醇、二甲基亚砜(DMSO)、N-甲基吡咯烷酮(NMP)作为萃取精馏分离异丁醇和正庚烷体系的备选萃取剂。比较了不同萃取剂对异丁醇和正庚烷体系相对挥发度的影响,并分析了异丁醇/正庚烷/NMP三元体系的剩余曲线图,结果表明:NMP为最佳的萃取剂。通过灵敏度分析确定了最小溶剂/进料比(S/F)为0.95。以年度总费用(TAC,即total annual cost)最小为目标函数,采用基于序贯迭代法的Visual Basic优化工具,对萃取精馏工艺进行了优化,确定出工艺的最佳操作参数以及最小TAC(1.08′106$/y)。在最优TAC工艺的基础上,利用Aspen Plus Dynamics软件,开发了基于温度和组成控制器的控制方案。通过比较不同S/F(1.0-1.3)下萃取精馏工艺的控制性能,发现了尽管增加S/F会导致TAC的增加,但是工艺的控制性能却得到提高。
[Abstract]:In this paper, three different aspects of thermodynamics analysis, process design and strengthening, dynamic control were carried out to study pressure swing distillation. A quantitative structure-activity relationship (QSP) method was proposed to study the azeotropic properties and thermodynamic properties of azeotropic compounds. The optimal operating parameters and the relationship between the optimal dynamic control structure and the molecular structure of azeotropic compounds. The composition descriptors, topological descriptors and space descriptors of 80 binary azeotropic mixtures containing low carbon alcohols were calculated, and 7 molecular descriptors were optimized by genetic algorithm. The model of azeotropic temperature and azeotropic composition of binary azeotrope containing low carbon alcohols was established. The reliability of the model was verified by internal and external verification. The determination coefficients of the optimal azeotropic temperature model were above 0.90) and the cross validation coefficient was 0.90, and the optimal azeotropic composition model was 0.87g / Rn2CV (0.82CV). The results show that the stability and prediction ability of the model are good. The data of vapor-liquid equilibrium were obtained by Aspen Plus software. By qualitative analysis, 1h2- propanediol and dimethyl sulfoxide DMSO-N- methyl pyrrolidone were selected as alternative extractants for the separation of isobutanol and n-heptane by extractive distillation. The effects of different extractants on the relative volatility of isobutanol and n-heptane systems were compared, and the residual curves of isobutanol / n-heptane / NMP ternary system were analyzed. The results showed that: NMP was the best extractant. According to the sensitivity analysis, the minimum solvent / feed ratio (S / F) is 0.95. Taking the annual total cost (TAC), that is, the minimum of total annual cost), as the objective function, and using the Visual Basic optimization tool based on sequential iteration method, the extraction distillation process was optimized, and the optimum operating parameters and the minimum TACN 1.08106g / yr / yr were determined. Based on the optimal TAC process, a control scheme based on temperature and component controller is developed by using Aspen Plus Dynamics software. By comparing the control performance of extraction distillation process with different S / F (1.0-1.3), it is found that the control performance of the process is improved even though the increase of S / F leads to the increase of TAC.
【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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