隔板塔多重定态特性的研究及其应用

Dividing wall column has become research hot topics in the field of thermally coupled distillation in recent years, due to its advantages of reduced energy consumption, lower capital investment and spot spaces. But up to now, people have not spent more attention to multiple steady states of dividing wall column, while the existence of multiple steady states for Petlyuk column has long been reported. Dividing wall column has the same thermodynamic structure, separation principle and simulation method as the Petlyuk column. In future, dividing wall column will be used for separation of more than four components which will lead to more internal interlinked streams, and coupled further with azeotropic distillation and reactive distillation respectively, all these will result in more serious consequence of its nonlinear characteristics and multiple steady states. Based on above consideration, in this project theoretical analysis and simulation, plus experimental evaluation will be used to study the multiple steady state of dividing wall column and its coupled new structure with azeotropic distillation and reactive distillation respectively. By mathematical analysis and numerical calculation of steady and dynamic models of dividing wall column, it can be predicted for the existence of multiple steady states and a stable solution method can be obtained. As research results of this project, we can give in-depth understanding of multiple steady states of dividing wall column, especially these rules on division of parameter space and phase space according to the number and features of steady states, which could help to develop and enrich the theory system of dividing wall column. In addition, these rules can be used to modify and improve the design, optimization, control and operation of dividing wall column. So, this project is of very important in science and application.

隔板塔因能够大幅度降低能耗、设备费用和占地面积，是热耦精馏领域的研究热点，但其多重定态特性并未引起人们足够的重视；而热耦精馏中与隔板塔构型的热力学特征、分离原理和计算方法基本相同的Petlyuk 塔已有存在多定态解的报道。随着隔板塔用于更多组分的分离而导致内部互联流股增多，以及隔板塔和共沸精馏、反应精馏的进一步耦合，其多重定态等非线性特性将更加突出。基于此，本项目拟通过理论分析、数值计算和实验验证，对隔板塔及其与共沸精馏和反应精馏的耦合形式的多重定态特性展开研究，通过对其定/动态数学模型的理论分析和数值计算，预测隔板精馏塔多重定态存在性条件及其适宜的求解方法。通过研究，可望深入认识隔板塔的多重定态特性的规律性，特别是参数空间按照定态数目与性质的分区和相空间分区的规律性，从而发展和丰富隔板塔理论体系；这些规律的应用，也将完善隔板塔现有设计、操作与控制方法。因此，具有重要的科学意义和应用价值。

隔板塔，作为一种热耦合集成塔型，引起工业和研究机构的广泛关注，已在工业装置上得到充分验证，显示出巨大的节能、降低投资和占地面积的优势。关于隔板塔的设计\控制，已发表许多文献，对其进行了深入研究。但是隔板塔多重定态特性以及对已有设计方法的影响，并未引起人们足够的重视。本项目对隔板塔的多重定态的内在机理进行了深入研究，建立了隔板塔的多种数学模型，例如稳态和动态模型，简捷设计模型和严格模拟模型等。稳态模型包括利用过程模拟软件建立的双塔模型、三塔模型、四塔模型，以及独立开发的隔板塔数学模型、数值算法和C++程序，对该种耦合塔型的数值求解、调试和收敛有了更深入的认识和积累。在上述模型基础上进行隔板塔的简捷设计和模拟优化，尤其是隔板塔耦合流股涉及到的多个变量的优化。经过验证，证实隔板塔也存在类似Petlyuk塔的多定态解，所以如何从多组解中筛选出最优的一组解用于后续工业化应用，就显得十分重要。本项目开发出一种快速诊断具体隔板塔系统是否存在多定态解的简便有效的算法，通过作图的手段，判断曲线是否相交以及交点的数目作为依据，直观形象。随后利用多组解的不同稳态和动态特性来筛选出，最适合于工业设计/加工/操作/控制的一组优化解，来进行后续的水力学设计。综合上述步骤，得到基于多重定态特性开发出一种的新的隔板塔设计方法，发展和丰富了隔板塔理论体系，对隔板塔的工业应用也起到重要的指导作用，具有重要的科学意义和应用价值。