设计演化算法实现精馏分离序列优化综合

采用演化算法求解具有组合爆炸特征的精馏分离序列优化综合问题。由于精馏分离序列与二叉树之问具有同构性．在数据结构上精馏分离序列可以抽象为二又树,直接采用二叉树结构编码方案可以同时表达个体的基因型和表现形。借鉴生物界父本可以经过有性繁殖或无性繁殖得到子代的现象。对遗传算子进行设计。应冒图论方法建立有效的二叉树结构演化重组机制,从而形成基于双亲或单亲父本的交叉算子。实例表明：双亲遗传操作其空间搜索率较低,而单亲遗传操作其最优解命中率较高。因此。演化算法能够成功解算大规模精馏分离序列优化综合问题。     

精馏分离序列综合超级结构研究

运用组合数学理论深入研究了精馏分离序列综合问题,简明分析了有序剖分问题的计算复杂性;在可行域中采用二叉树数据结构,实现了对精馏分离序列的随机搜索;通过中间结点和叶子结点相互变换机制,构造了一种高效演化邻域(超级)结构。     

油页岩热解煤气粗苯精制的分离序列研究

为提高从油页岩热解煤气中回收的粗苯产品的经济效益,研究了对回收的粗苯进行精制的分离序列,模拟常规精馏序列和热耦合精馏序列分离粗苯的过程并计算其能耗和热力学效率.结果表明,在轻组分含量较高的粗苯精制分离序列中,完全热耦合精馏序列仍然具有较好的节能效果.其能耗比常规精馏序列中能耗最小的直接分离序列节能约35％,热力学效应也由7.4％提高到11.6％.     

基于非关键组分的精馏序列和反应参数优化

多个精馏序列可用于分离多组分混合物,其能耗和投资费用均与其非关键组分总流量正相关,可据此辨识最优精馏序列。考虑反应器对精馏序列的影响,系统推导了反应器原料、操作参数和反应器流出物的关系,探究各组分在精馏序列作为非关键组分存在的规律,提出以非关键组分矩阵表征不同精馏序列和据此辨识最优精馏序列的方法。案例分析表明所提出的方法可简单、准确地确定分离不同组分数的混合物的非关键组分矩阵、边际气相流率和最优精馏序列。     

隔壁塔分离乙醇-正丙醇-正丁醇体系

以乙醇-正丙醇-正丁醇为分离体系,研究回流比、气液分配比等操作参数对隔壁塔分离效果的影响。将常规双塔精馏序列转化为隔壁精馏序列并保证各操作参数的最优值,利用Aspen Plus模拟软件对乙醇-正丙醇-正丁醇三组元的常规精馏序列和隔壁塔精馏序列进行模拟分析,探究隔壁精馏工艺最佳操作区域及节能效果,模拟结果表明,在满足分离要求下,气液分配比存在一个相互关联关系,使隔壁塔精馏序列存在一个再沸器热负荷最小的最佳操作区域。与常规精馏序列相比,完成相同的分离任务,隔壁塔精馏序列再沸器节能6 954.368 k W,冷凝器热负荷减少2 934.291 k W。结果表明,隔壁塔精馏序列不但提高了热力学效率、降低了能耗,并且大幅降低设备投资。     

基于模糊逻辑推理的精馏分离序列优化综合

模糊逻辑推理能够反映自然语言要素信息传递特性. 通过抽象有效重组参数提炼if-then模糊逻辑推理规则、根据精馏分离序列综合问题数字特征创建Sugeno模糊逻辑推理模型,系统化地提出了基于模糊逻辑推理的精馏分离序列优化综合方法.     

基于带权有向图的非清晰复杂精馏序列的合成方法

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。     

一种复杂精馏流程的编码表达法

提出一种多组分精馏流程的编码表达法,适用于由简单塔、带有侧线汽提或侧线精馏类型的塔以及Petlyuk类型的塔等单元构造的分离流程.首先根据塔段数和换热器数目之间的关系导出所有可能的分离方案,其次用整数作为编码来产生所有可能的分离任务顺序和换热器方案,最后用二叉树方法建立编码组合与流程结构之间的映射关系,从而实现整个流程的合理表达.同以往的方法比较,本文方法的适用范围更广,可表达更复杂的分离流程,同时简单易行.     

多组分混合烷烃分离序列的合成优化研究

多组分精馏序列的研究是降低多塔精馏分离能耗的重要手段.本文采用双塔精馏分离正丁烷、正戊烷和正己烷混合物,对两种分离序列进行比选,两种工艺分别记为工艺a和工艺b,以产品纯度相同与能耗最小化为依据,采用Aspen plus对两种工艺进行模拟优化,得出工艺a的总能耗为1383.53 kW,工艺b的总能耗为1151.94 kW...     

应用遗传算法实现精馏分离序列优化综合

阐述了采用遗传算法求解具有组合爆炸特征的精馏分离序列综合问题。首先在数据结构上将精馏分离序列抽象为二叉树结构编码,然后应用图论方法建立起有效的交叉和变异算子,最后对10组分精馏分离序列综合问题实例进行求解。结果表明,遗传算法对最优解命中率达80％,平均空间搜索率仅为0．0318。因此遗传算法能够成功解算大规模精馏分离序列优化综合问题。     

考虑中间换热器的能量集成精馏序列合成

针对考虑中间换热器（IHE）的精馏序列合成问题,提出基于随机优化策略的能量集成非清晰精馏序列（IHE-HIDSs）合成方法。通过对精馏序列分离任务合并处引入二元0/1变量表示是否存在IHE,以精馏序列的年总成本（TAC）为优化目标,建立了该合成问题的隐式混合整数非线性规划模型（MINLP）,通过模拟退火和粒子群优化（SA-PSO）混合随机优化算法进行求解。为验证在精馏序列合成中同时考虑IHE的必要性以及所提出合成方法的有效性,对五组分醇类混合物和五组分烷烃类混合物两个算例的精馏序列合成问题进行了研究。结果表明,相比同时考虑热耦合和能量集成的精馏序列,IHE-HIDS具有更低的TAC。此外,所提出的方法可以在合理的计算时间内以高概率获得多个分离序列方案。     

基于介电性质差异的微波诱导强化蒸馏分离

具有选择性加热特性的微波辐射场对混合物相对挥发度影响的发现，对基于混合物介电性质差异而实现化工分离新技术的开发和工程强化能起到极大的推动作用。本文梳理了近年来发展的微波场强化化工分离方法，阐述了微波场与各类物质的特殊作用机制，重点介绍了微波场诱导强化极性-非极性混合物蒸馏分离新技术的相关研究。针对微波诱导分离技术在实际应用中亟需解决的关键问题，着重综述了作者课题组在微波诱导分离机理、分离装置与微波腔体结构设计及过程模型方面的研究进展。最后，对微波技术在化工分离过程强化领域应用目前尚存在的问题提出建议，期望对未来通过介电性质差异实现分离的发展方向提供参考。     

基于随机优化的热耦合复杂精馏系统的综合(Ⅰ)模型化方法

基于随机型最优化策略,针对包含简单塔、带有侧线蒸出及侧线汽提塔的复杂塔、全热耦合（或Petlyuk）塔的热耦合复杂精馏塔系统的综合问题,提出一种模型化方法.针对热耦合复杂精馏流程系统所需塔段数目以及冷凝器和再沸器数目的不确定性,提出了一种分解求解策略,将原问题分解成一系列具有不同塔段数的子问题分别求解;针对流程结构的优化提出一种流程结构的编码表达法,该方法将问题的分离序列结构和热耦合方式分别用两组编码表示,对分离序列的编码采用了数据结构理论中的二叉树排序方法,使流程结构的描述变得更加简便;最后以预分馏塔组分回收率及回流比为连续变量,建立了热耦合复杂精馏系统优化的[JP+1]混合整数非线性规划（MINLP）模型,该模型用改进的模拟退火算法求解,可同时得到优化的流程结构和操作参数.     

A new bounding strategy for synthesizing distillation schemes with energy integration

An efficient method is developed for synthesizing distillation systems with energy integration. In order to reduce the search space a predictor-based ordered-search technique is used. The main feature of the two-level method is the utilization of the heat-cascade theory by setting up lower bounds for all feasible energy-integrated separation sequences. A separation structure can be built up from individual columns, two-column matches and higher-order integrated matches as well. The objective function of the optimal separation system is the total annual cost, which is a combination of capital and operating expenses. For comparison with previous works, in this study the pressures and reflux ratios of distillation columns are selected as design variables. The effectiveness of the synthesis method is demonstrated on the five-component example of Heaven. The algorithm, utilizing the heat-cascade theory, can be simply implemented on computer.

Scope—Chemical processes frequently apply distillation systems for separating multicomponent mixture into products with relatively pure species. The task of synthesizing optimal (or a small number of near-optimal) separation sequences with heat integrations often represents a huge combinatorial problem. The number of feasible separation schemes increases rapidly as the number of components to be separated increases. Because the computation time and cost for the analysis of separation processes are not negligible, it is desirable to have procedures for determining the optimal (or a small number of near-optimal) separation structures without examining all the possible schemes. In order to reduce the search space of the synthesis problem several systematic procedures have been developed.

Unlike previous methods, the predictor-based ordered-search method proposed here utilizes the heat-cascade theory [1, 2]. By applying the heat-cascade theory a minimum value can be predicted for the total annual cost of all heat-integrated sequences without detailed evaluation of all possible heat matches. The predicted minimum cost can be used as lower bounds for the objective function. The lower bounds are computed as the sum of the actual total annual cost of the unintegrated substructure and a prediction of the minimum cost for that part of the remaining substructure to be integrated. The structures are ordered according to the lower bounds and the heat matches are optimized starting with the structure of the lowest lower-bounding value. The optimized total annual cost of the best sequence is used as a continuously renewed upper bound. The search for a better candidate is complete when the lower bound of the forthcoming structure in the order exceeds the upper bound. In this manner, the predictor-based ordered-search strategy proposed here is capable of omitting a large number of feasible separation schemes and heat matches, and can save considerable computer time.

Conclusions and Significance—The method reported here for synthesizing heat-integrated distillation systems applies a predictor-based ordered-search technique. Using the heat-cascade theory a minimum value for the total annual cost of all the separation structures can be estimated. These minimum values are assigned to the corresponding structures and used as lower bounds of the objective function. The important feature of the method is that mathematical guarantees on the elimination of uneconomical solutions are maintained, hence the optimal solution for heat-integrated distillation schemes is not eliminated by the search reduction. The new bounding strategy could be combined, to include that integration, with the method proposed by Gomez and Seader [3]. The effectiveness of the method is demonstrated on a five-component hydrocarbon mixture where only 20% of the feasible separation structures had to be examined.     

A mass and energy balance stage model for cyclic distillation

Cyclic distillation is an emerging process intensification technology, which can improve separation efficiency compared to conventional distillation. As most current models only account for the mass transfer, there is a lack of a stage model for cyclic distillation processes, which includes considerations of both mass and energy transfer. Such a model is presented in this article, and using this model, selected case studies, describing binary and multiple component systems with both ideal and nonideal liquid phases, are investigated. The presented stage model allows for the modeling of both mass and energy transfer for a cyclic distillation process and allows for multiple feed locations, as well as side draws. With the energy balances included, the dynamic vapor flow rate can be described. This was shown to have a significant effect on the separation, especially for cases where the change in the vapor flow over the column height was high.     

Synthesis,experiments and simulation of heterogeneous batch distillation processes

The presence of azeotropes in multicomponent mixtures complicates the design of batch distillation separation processes widely used in pharmaceutical and speciality chemical industries. Most of those processes include the use of a homogeneous entrainer to ease the separation. We describe novel methods to break azeotropes using an entrainer that is partially miscible with one of the initial binary mixture components. We depict some of the advantages of heterogeneous batch distillation processes: more design alternatives for the separation of an azeotropic binary mixture than with homogeneous batch distillation, batch distillation boundary crossing thanks to a controlled reflux of the entrainer-rich phase, simplified distillation sequences as a consequence of less distillation tasks. Three examples based on the separation of non-ideal azeotropic or close boiling point binary mixtures through heterogeneous batch distillation are simulated using a commercial batch distillation package. Experiments validate the simulated separation of a minimum boiling azeotropic mixture.     

分子蒸馏纯化茶树油的研究

方法：利用分子蒸馏考察了蒸馏温度、操作压力和刮膜转速对茶树油纯化效果的影响。结果：初步得到一级分离参数：蒸馏温度为50℃,操作压力为1IOPa,刮膜转速为150r／min。经过四级分子蒸馏,4-松油酵由原来的39．53％提纯至83．04％。分离过程收率达到44．77％。结论：利用分子蒸馏可以较好地纯化茶树油中的4-松油醇,并为今后工艺参数优化奠定了基础。