【作者】 武国松；

【导师】 黄克谨；

【作者基本信息】 北京化工大学 ， 控制科学与工程， 2010， 硕士

【摘要】 以内部热耦合技术为基础的理想热耦合精馏塔(ideal heat-integrated distillation column, HIDiC)作为精馏塔的一个前沿发展,近年来高效率低能耗的特性备受研究学者的青睐。尽管理想HIDiC的概念上世纪就被提出,但对其的研究都停留在理论阶段没有实际应用到化工过程。究其原因是在精馏塔内部设计和应用热耦合技术时,管壳内部狭小的空间造成了障碍。因此,对于更易设计与应用的HIDiC简化结构的研究有其必要性。从实际的观点考虑,用三个外部换热器近似代替HIDiC精馏段和提馏段之间的耦合部分在理论上是可行的。为此本文提出了理想HIDiC(简称S-0)的三种简化设计。一种是精馏段和提馏段的顶部,中间和底部分别设置换热器的设计(简称S-1)；一种是顶部和中间换热器都设置在精馏段顶部塔板,提馏段顶部蒸汽经压缩与提馏段底部换热构成底部换热器的设计(简称S-2)；另一种是顶部、中间和底部换热器都设置在精馏段顶部塔板的设计(S-3)。对理想HIDiC以及三种简化设计分别建立相对应的稳态数学模型和动态数学模型,进行综合与设计,并以乙烯乙烷二元理想物系分离为例,从固定传热面积和精馏段顶部压力两个方面对三种简化设计进行模拟仿真,研究简化设计对理想HIDiC性能的影响。结果表明S-1的静态性质不如S-0,但动态特性得到了改善。S-2和S-3设计可以减小操作费用和操作费用,但相比于S-1的动态可控性变差。尽管通过增加换热器的面积能够减少操作费用,但简化设计加强了顶部回路和底部回路的交互性,恶化了系统的动态特性和可控性。为了得到更有效的HIDiC的简化设计,应该合理考虑过程综合与设计和系统动态特性与可控性的均衡。更多还原

【Abstract】 As one of most advanced schemes for distillation columns, ideal heat-integrated distillation column (Ideal HIDiC), which is characterized by internal heat integration between rectifying section and stripping section, features highly thermodynamic efficiency and great potentials of energy saving. Although its invention is dated back to 1990s, it still remains at the stage of theoretical studies and is not yet put into applications in the chemical and petrochemical process industries. The reason can be partially attributed to the extreme difficulties and great complexities encountered in the design and implementation of this kind of internal heat integration into a conventional distillation column, due to the quite limited space within the column shell. Therefore, it is necessary to study the philosophy for the synthesis and design of the ideal HIDiC.According to the viewpoint of structural and functional equivalence, it is topologically feasible to approximate internal heat integration between the rectifying section and the stripping section with three heat exchangers. In this thesis, three process simplifications are derived and studied for an ideal heat-integrated distillation column (S-0). These include one with the heat exchangers located in the tops, middles, and bottoms of the heat-integrated sections respectively (S-1), one with the vapor flows from the top of the rectifying section and compressor as hot flows in the top, intermediate, and bottom heat exchangers respectively (S-2), and one with the vapor flow from the top of the rectifying section as hot flows in the top, intermediate, and bottom heat exchangers respectively (S-3).With the established static and dynamic models of the ideal HIDiC and its simplifications, the impacts of process simplifications on the static and dynamic behaviors are examined based on the separation of an ethylene/ethane binary mixture. It is found that the S-1 is inferior to the S-0 in static performance but with comparable dynamic behaviors. The S-2 and S-3 show smaller capital investment and operating cost than the S-1 but with a sharp degradation in process controllability. Although the augment of total heat transfer areas of the three internal heat exchangers could lead to a reduction in operating cost, almost no favorable effect is identified on process operation. In order to derive a feasible simplification of the ideal HIDiC, one has therefore to exercise a careful trade-off between process synthesis and design and process dynamics and controllability.更多还原