换热器网络同步最优综合方法──改进的MINLP转运模型法

针对现有的换热器网络最优综合方法的局限性，采用分级超结构转运模型和物流吸、放热潜力的概念，提出了非等温混合线性约束的换热器网络同步最优综合混合整数非线性规划（MINLP）的改进模型．该模型不仅可以对公用工程费用、换热面积、换热设备台数及物流的匹配选择进行多目标同步优化，而且在线性约束的条件下消除了等温混合的不合理假设，只需求解一次MINLP问题就可得到包括分流情况在内的最优网络结构．算例表明，该模型优于以往的几种同步优化模型．     

过程全局夹点分析与超结构MINLP相结合的能量集成最优综合法

提出了过程全局夹点分析与超结构混合整数非线性规划 (MINLP)相结合的能量集成最优综合法 .各单过程内部换热优化匹配后 ,进行各过程剩余冷、热负荷与公用工程系统的全局夹点分析 ,确定全局热集成目标 ,在此基础上建立包含过程剩余热负荷产生各等级蒸汽、剩余冷负荷使用各等级蒸汽加热的各种可能匹配方案的公用工程换热网络超结构及其MINLP模型 ,采用混合连续进化算法求解得到过程与公用工程换热网络最优改造方案 .大型乙烯装置能量集成应用算例表明 ,可充分发挥全局夹点分析法确定改造目标的简洁实用性和超结构MINLP寻求最佳方案的优点     

基于群体智能算法的换热网络同步最优综合

换热网络同步综合方法一般需要建立复杂的混合整数非线性数学规划模型,该模型具有非凸、非线、不连续的特点,属于最难求解的一类NP-hard问题,应用传统的优化算法很难确定其全局最优解,尤其是对大规模换热网络综合问题,甚至无法在合理时间内接近全局最优的局部最优解。针对换热网络同步综合问题,提出基于群体智能算法的分层优化策略,外层采用离散粒子群算法与遗传算法相结合的混合群体智能算法优化换热网络结构,内层在结构变量给定条件下利用改进粒子群算法优化冷热物流分流比与换热负荷。两个典型算例研究证明了该方法能以较高的效率和稳定性得到较好的优化结果。     

棋盘模型在换热网络优化中的应用

针对复杂整数非线性的换热器网络综合和优化问题,文中应用换热网络流程模拟的棋盘模型及其相应的算法,建立了换热网络同步最优综合的数学模型,通过改变网络的结构次序的数学规划优化计算,以10SP1问题为例,获得了优于以往文献的最优换热网络结构。结果表明,文中应用棋盘算法建立的换热网络求解模型及其算法,具有简单、直观、灵活、易实现的特点,能够得到综合性能更优的网络结构。     

基于AEA和PSO的双层同步换热网络综合方法研究

换热网络优化是一个多维、非凸、非线性、不连续的复杂混合整数非线性规划问题,传统的优化方法很难寻找到全局最优解。针对该问题研究建立了换热网络分级超结构非等温混合模型,提出了一种双层同步优化算法。该算法外层使用Alopex Evaluation Algorithm(AEA)算法优化结构变量分流比,内层使用Particle Swarm Optimizer(PSO)算法优化换热量。还提出了一种改进的不可行解修复策略,改善了算法的搜索能力。三个案例研究用以说明算法可以稳定寻找到较好的优化结果。     

工艺过程与换热网络的联合优化

提出了用超结构回归模型法来解决工艺过程与换热网络联合优化综合的课题,并且对超结构中整型变量的处理提出了整型变量连续化的方法,为有效地求解混合整数非线性规划问题(MINLP)提供了一种新的途径;应用该方法对某化肥厂的改造扩建进行了优化计算,表明该方法的应用可以产生很大的经济效益.     

数学规划与图形方法相结合设计热集成用水网络

将数学规划法与图形方法相结合探究单杂质用水网络与换热网络的集成问题。首先构建混合整数非线性规划模型（MINLP）,在最小公用工程消耗下优化流股参数未知情况下的分离系统组合曲线面积,得到了最为节能、换热面积最小的用水网络结构。在此基础上,提出了新的分离系统组合曲线演化步骤和规则,可以得到换热单元数目较小的换热网络结构。算例表明,与现有的基于分离系统的热集成用水网络设计方法相比,在最小化公用工程用量的同时可以进一步降低换热器数目与总换热面积。     

过程工业蒸汽-凝结水-换热网络协同集成优化

针对传统蒸汽作为公用工程只利用潜热部分的不足,提出蒸汽潜热和显热与工业企业换热网络同步集成的新思路,建立同步集成优化的超结构和数学规划模型,获得总费用最小的换热网络匹配及蒸汽系统设计方案,并通过案例对比,得到总费用节省12%的优化效果。     

换热网络填充函数法的全局优化

换热网络全局优化问题属于混合整数非线性规划范畴,其难点是目标函数和约束条件呈现为严重的非线性和非凸特性,局部最优解陷阱星罗棋布.针对其全局优化的难点,应用一种变换函数的全局优化方法--填充函数法,对换热网络进行全局优化.通过具体的填充函数对某特定算例进行求解表明,通过不断的交替优化,填充函数能够使换热网络目标函数跳出局...     

改进的无分流换热器网络最优综合法

提出了不分流换热网络改进的同步最优综合混合整数非线性规则模型，通过引入处理带０－１整型变量的规则，提出了采用非线性规划求解换网络综合ＭＩＮＬＰ问题的方法，只需求解ＮＬＰ问题就可得到连续变量和０－１变量同步优化的网络结果。算例表明，该模型和方法是有效的。     

New developments and capabilities in prosyn—An automated topology and parameter process synthesizer

This paper describes an improved, equation oriented user friendly version of the modular computer package PROSYN—a mixed-integer nonlinear programming (MINLP) process synthesizer. A number of strategies are described and implemented for the outer approximation and equality relaxation algorithm (OA/ER) in order to reduce the undesirable effects of nonstructured nonconvexities in the master problem. These strategies include use of valid outer-approximations for splitters and mixers and various ways of handling the linearizations. An NLP initializer, model generator and a comprehensive library of models for basic process units and interconnection nodes, and a comprehensive library of basic physical properties have been developed and built in the PROSYN package. In this way PROSYN can be used to solve problems at different levels of complexity: from the simple NLP flowsheeting up to the MINLP synthesis through the modeling and decomposition (M/D) strategy and simultaneous heat integration including HEN costs. Applications with PROSYN are demonstrated with several example problems.     

Simultaneous process synthesis,heat, power,and water integration of thermochemical hybrid biomass,coal, and natural gas facilities

A comprehensive wastewater network is introduced into a thermochemical based process superstructure that will convert biomass, coal, and natural gas to liquid (CBGTL) transportation fuels. The mixed-integer nonlinear optimization (MINLP) model includes simultaneous heat, power, and water integration that utilizes heat engines to recover electricity from waste heat and several treatment units to process and recycle wastewater. A total of 108 case studies are analyzed which consist of combinations of six coal feedstocks, three biomass feedstocks, three plant capacities, and two process superstructures. This study discusses important process topological differences between the case studies and illustrates each component of the process synthesis framework using the two medium-sized capacity case studies that have low-volatile bituminous coal and biomass feedstocks.     

Design of flexible heat exchanger network for multi-period operation

Heat exchanger networks (HENs) increase heat recovery from industrial processes by matching hot and cold streams to exchange heat and reducing utility consumption. The design of HENs is a very complex task which generally involves mixed-integer non-linear programming (MINLP).This work evaluates and critically compares existing HEN design methods. It then presents a systematic methodology in the design of HENs under multiple periods of operation. The model presented in this work is a superstructure-based MINLP model which minimises the total annualised cost containing heat exchanger area cost and utility costs. The model is based on the superstructure by Yee and Grossmann [1990. Simultaneous optimisation models for heat integration—II, heat exchanger network synthesis. Computer & Chemical Engineering 14(10), 1165-1184], which was later formulated for multiple periods by Aaltola [2002. Simultaneous synthesis of flexible heat exchanger network. Applied Thermal Engineering 22, 907-918]. It includes a multi-period simultaneous MINLP model to design the HEN structure, and an NLP model to improve the solution and allow for non-isothermal mixing. Modifications to Aaltola's model include the use of maximum area per period in the area cost calculation of the MINLP objective function, and the removal of slack variables and weighed parameters from the existing NLP improvement model.The new model has been applied to one industrial case study, demonstrating that the new combined MINLP-NLP model can obtain better solutions by not relying on the average area assumption in the MINLP stage.     

多流股换热器网络综合方法在原油预热系统中的应用

以原油常减压蒸馏装置原油预热网络为研究对象,进行了多流股换热器网络的实例综合. 基于超结构物理模型建立了改进的多流股换热器网络综合数学模型,提出将该网络综合问题由混合整数非线性规划问题转化为简单的非线性规划问题的求解策略,并利用改进的遗传/模拟退火新算法进行了原油预热网络的综合. 与Hextran软件的综合结果以及现场换热网络的对比表明,本模型和求解策略可以应用于工业规模的多流股换热器网络综合,有可能取得较好的经济效益.     

Simultaneous synthesis of distillation sequences in overall process schemes using an improved minlp approach

This paper describes the synthesis of distillation sequences simultaneously with the synthesis of other process subsystems. An improved MINLP approach is proposed for the synthesis of complex problems. The improvements were made on three major MINLP levels. By postulating the superstructures we propose to use smaller and more compact superstructures of the distillation sequences included in the flowsheet superstructure rather than the usual tree and network representations. In the modelling step a higher degree of simultaneity has been accomplished by the use of simultaneous models of the distillation column and aggregated models of other process units. To facilitate the optimization phase the modified OA/ER algorithm [Kravanja and Grossmann, Ind. Engng. Chem. Res.26, 1869–1880 (1994)], implemented in the computerized synthesizer PROSYN-MINLP, has been used to reduce the effect of nonconvexities. Also, a special initialization and linearization scheme for simultaneous synthesis of HEN has been proposed. The improved method is illustrated by the synthesis of the separation subsystem followed by the simultaneous synthesis of the heat integrated separation system and its heat exchanger network (HEN). Finally, the optimization of the overall process and the simultaneous synthesis of its distillation system and heat integrated HEN is presented.     

混合整数非线性规划与化学工程系统最优化设计——(Ⅱ)换热器网络的最优合成

本文讨论了用系统方法进行换热器网络的最优合成问题.建立了该系统的超结构及其混合整数非线性规划(MINLP)模型,并成功地应用了前文导出的MINLP算法对一算例进行求解.计算结果表明,本文所采用的方法在对系统的结构与操作参数同时进行优化方面,优于以往一些方法.     

Optimal synthesis of heat exchanger networks involving isothermal process streams

This paper proposes a new MINLP model for heat exchanger network synthesis that includes streams with phase change. The model considers every possible combination of process streams that may arise within a chemical process: streams with sensible heat, streams with latent heat, and streams with both latent and sensible heat. As part of the optimization strategy, the superstructure is modeled with logical conditions that are used for the proper placement of heat integration for streams with change of phase. The proposed MINLP model provides the network structure that minimizes the total yearly cost. Several examples are presented to illustrate the capabilities of the proposed model.     

用于热集成精馏序列综合的改进模拟退火算法

提出一个用于多组分热集成精馏系统综合问题的改进模拟退火算法.将优化问题表示为混合整数非线性规划（MINLP）问题,将算法设计同研究问题的特征相结合,运用本文方法可在同一退火策略下实现流程结构和操作参数的同步优化,并能达到计算精度和计算速度的更好均衡.通过对大规模算例（产品数≥10）的计算表明,该方法对求解此类问题非常有效.