Abstract:

Nonsharp split can improve the thermodynamic efficiency of the distillation system due to its avoidance of the remixing effects which are inherent to sharp split. Based on the Data Structure Theory, a method is introduced to synthesize and optimize the nonsharp complex distillation sequences. For an N-component mixture separation, the distillation sequences is comprised of N-1 columns, the nonsharp splits of which contain an arbitrary number of middle components. In order to synthesize the separation sequences above, the weighted directed digraphs can be applied to establish a new model which is suitable for the distillation columns. Additionally, based on the dynamic array “vector”, a storage structure of the weighted directed graphs, which combines the advantages of arrays and chain tables, is proposed. A series of operations are defined in the synthesis procedure and the breadth-first strategy is chosen to improve the synthesis efficiency. An example problem is solved to illustrate the high efficiency of this method. The results show that the optimal sequence of the example problem can effectively reduce investment cost and energy consumption.

Key words: nonsharp split, separation sequence, weighted directed digraphs, synthesis, distillation, system engineering

摘要：

在精馏系统中非清晰分离能够克服清晰分离所固有的返混效应，从而提高系统能效。基于数据结构理论，提出了非清晰精馏序列的合成与优化方法。对于N组元混合物的分离，合成的精馏序列由N-1个精馏塔构成，且其中的非清晰分离任务含有所允许的任意多个中间分配组分。为了合成上述分离序列，利用带权有向图建立了一种新的精馏分离序列模型，并基于“vector”动态数组，提出了一个同时拥有数组和链表优点的带权有向图的储存结构。序列合成过程定义了一系列的相关操作，且选择广度优先的策略以提高合成效率。算例证明了该方法在精馏序列合成和优化的高效性。算例结果表明该算例的最优分离序列可以有效减少设备投资和能耗。

关键词: 非清晰分离, 分离序列, 带权有向图, 合成, 精馏, 系统工程