水网络与虚拟水的过程系统工程研究进展

水危机的迫切性已经引起了全世界过程系统工程领域的普遍关注。首先概述了全球和中国水危机的严重情况, 介绍了政府和学术界的对策, 系统地检索了1994年以来对水网络和虚拟水问题发表的文献著作。分3个层次对国内外的研究做了系统综述:①单个企业内水网络系统集成优化, 包括用水网络(WUN)、废水处理网络(WWTN)、总水网络(TWN)和全水网络(CWN)及冷却循环水系统问题、有中水道水网络和间歇水网络问题3个特殊问题;热量和水耗同时最小化的水配置和换热网络问题(WAHEN);多种工艺与能、水网络系统同时集成优化研究;②跨企业多个水网络系统集成优化;③跨地区/国家的虚拟水与产品水足迹研究。这些研究对企业的、跨企业的生态工业园区以及区域产业系统的节水减排和提高水、能的利用效率可以发挥重要作用, 并对解决缺水地区/国家的政策制定提供依据。     

考虑非等温混合的能量集成用水网络综合

提出了考虑非等温混合的新的水网络模型,并结合线性规划（LP）转运模型同时优化水网络的水耗及公用工程目标。新的水网络模型引入非等温混合以改善用水网络的能耗特性及减少模型中参与集成换热网络的流股数,从而降低设计换热网络的复杂程度。在确定水网络的水耗及公用工程目标后,采用夹点法设计详细的换热网络结构。两个算例结果表明,新的水网络模型不仅能确定用水网络的最优水耗及公用工程目标,而且还能得到一个更加简单的换热网络。这对节省设备投资及减少操作费用具有重要意义。     

Novel graphical tool for the design of the heat integrated water allocation networks

A new graphical tool has been developed for the HEN design of WAHEN. An ΔH‐F diagram is proposed to deal with the heat exchange matches. Nonisothermal stream mixing and splitting can be achieved by the transformation of stream composite curve in the ΔH‐F diagram. A matching composite curve is proposed for the design of HEN with parallel structure. The structure of HEN can be simplified by adjusting the shape of the matching composite curve. Both small scale and large scale examples are illustrated. Results show that the proposed method is as good as the previous methods for small scale problem, while it gets a better result for large scale problem. © 2015 American Institute of Chemical Engineers AIChE J, 62: 670–686, 2016     

考虑非等温混合的能量集成多杂质水网络优化设计

提出了一种分步综合多杂质体系水网络和换热网络的新方法。对于水网络,考虑进入操作单元的新鲜水与回用水之间的非等温混合,确保流股间的直接热回收;对于换热网络,可以只考虑水网络中的新鲜水和回用水流股之间的换热匹配。采用无进化次数的改进粒子群算法对本文建立的多杂质体系水网络非线性模型和换热网络混合整数非线性模型进行求解。实例表明,与不考虑非等温混合时比较,考虑非等温混合时的最优网络结构更简单,且年度总费用要节省2.4%。因此,本文提出的方法在实际生产中有较好的可行性和有效性。     

Synthesis of non-isothermal heat integrated water networks in chemical processes

This paper presents a new approach for the simultaneous synthesis and optimization of heat integrated water networks. A new superstructure for heat exchanger network (HEN) synthesis is proposed. The procedure is based on mixed integer non-linear mathematical programming (MINLP). Four relevant examples are presented to illustrate various aspects of the proposed approach.     

通过流股的合理合并改进用水网络的能量效率

Water-using operations in the process industry have demands for water usually both on water quality and temperature, and the existing mathematical models of heat exchange networks cannot guarantee the energy performance of a water network optimal. In this paper, the effects of non-isothermal merging on energy performance of water allocation networks are analyzed, which include utility consumption, total heat exchange load, and number of heat exchange matches. Three principles are proposed to express the effects of non-isothermal merging on energy performance of water allocation networks. A rule of non-isothermal merging without increasing utility consumption is deduced. And an approach to improve energy performance of water allocation network is presented. A case study is given to demonstrate the method.     

换热网络设计方法的研究进展

回顾了近年来换热网络设计研究的内容和方法。分析了当前求解换热网络最小公用工程设计的3种方法：传统的给定工艺条件的设计法、最近几年得到很大发展的弹性设计法和控制与工艺一体化设计法。阐述了这些方法各自的优势和尚待改进的问题,并指出换热网络的设计同时应考虑先进控制和动态优化,先进控制与工艺一体化换热网络设计是今后的发展方向。     

考虑操作分解的热集成用水网络设计

This article deals with the design of energy efficient water utilization systems allowing operation split. Practical features such as operating flexibility and capital cost have made the number of sub operations an important parameter of the problem. By treating the direct and indirect heat transfers separately, target freshwater and energy consumption as well as the operation split conditions are first obtained. Subsequently, a mixed integer non-linear programming （MINLP） model is established for the design of water network and the heat exchanger network （HEN）. The proposed systematic approach is limited to a single contaminant. Example from literature is used to illustrate the applicability of the approach.     

利用余热回收多能互补技术的原油蒸馏装置热集成系统的优化改造

针对换热网络（HEN）的优化改造,提出了一种利用公用热量实现多能互补理念的改造思路,通过充分利用热过程物流中的低温余热,完成热集成系统的优化改造。本文基于参考点非支配排序遗传算法（NSGA-Ⅲ）,通过综合评估集成废热回收（WHR）系统的换热网络的年度改造费用、年度改造收益、能耗（包含换热网络的冷/热公用工程和废热系统冷却水和电力消耗）和废热系统的有益产出,从而获得最优解决方案。对原油蒸馏系统（10H5C）的优化改造研究案例表明,通过权衡集成系统的能源消耗、WHR系统的产出、改造费用和改造收益4个目标,采用NSGA-Ⅲ算法求解获得了多维度的改造方案,相较于基础网络不仅有可以为用户最大节省22.9%能源消耗的改造方案,还有WHR系统最大输出为4.003×10⁴kW的解决方案,也有最小改造费用为1.848×10⁶USD/a的改造方案,还有最大改造收益和最大投资回报率分别为1.173×10⁷USD/a和121%的解决方案;最后通过比较集成WHR系统与单独HEN优化改造的性能,证明了集成WHR系统的实用性和可行性,以及余热回收多能互补技术对提高流程工业能量集成系统能量利用效率的重要作用。     

Simultaneous optimization of water and heat exchange networks

This paper focuses on the simultaneous optimization of the heat-integrated water allocation networks. A mathematic model is established to illustrate the modified state-space representation of this problem. An easy logical method is employed to help identify the streams of hot or cold ones. In this model, the water exchange networks (WEN), heat exchange networks (HEN), and the interactions between the WEN and HEN combine together as one unity. Thus, the whole network can be solved at one time, which enhances the possibility to get a global optimal result. Examples from the literature and a PVC plant are analyzed to illustrate the accuracy and applicability of this method.     

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。     

Optimum heat storage design for solar‐driven absorption refrigerators integrated with heat exchanger networks

A methodology is presented for optimizing hybrid renewable energy‐fossil fuel systems with short‐term heat storage. The considered system is an absorption‐refrigeration (AR) cycle integrated with a heat exchanger network (HEN) requiring cooling below ambient temperature. The AR cycle can be driven by multiple energy sources including excess energy from hot process streams, renewable energy sources (solar and biofuels), and fossil fuels. A two‐step approach based on mixed integer nonlinear programming methods is used for the optimization. First, the problem of optimal energy integration in the hybrid energy system without heat storage is solved on a monthly basis by minimizing simultaneously the total annual cost and the overall greenhouse gas emissions. In the second step, the multi‐tank thermal energy storage (TES) design problem is solved. The design involves the identification of the optimal number of storage tanks, their sizes, configuration and operation policies. The TES optimization is carried out on an hourly basis while incorporating the design targets determined by the first step. © 2013 American Institute of Chemical Engineers AIChE J, 60: 909–930, 2014     

Simultaneous optimal integration of water utilization and heat exchange networks using holistic mathematical programming

A systematic holistic mathematical programming (HMP) is proposed to formulate a mixed integer nonlinear programming (MINLP) model for one-step optimization of water-allocation and heat exchange network (WAHEN) designs with single- or multi-contaminant water streams. The proposed model formulation and solution strategy are believed to be superior to the available ones in the following aspects. First, a comprehensive representation combining two separate superstructures is adopted to capture the structural characteristics of the integrated WAHEN. Then, a hybrid optimization strategy integrating stochastic and deterministic components is developed for the resulting MINLP model and, also, an interactive iteration method is adopted based on sensitivity analysis to guide the search toward a potential global optimum. Finally, evolutionary strategies and manipulations are executed to enhance WAHEN configurations. Two illustrative examples are presented to demonstrate the validity and advantages of the proposed approach.     

基于经济目标和分解协调策略的换热网络最优设计

分析了换热网络在过程系统中的功能 ,从火用分析和火用经济学的角度提出了换热网络最优合成设计的实用火用经济目标函数 ,它包含了网络的流动火用损费 ,且可分解为各个换热单元的总费用之和 .在换热网络目标函数可分解性的基础上 ,本文又进一步提出了换热网络分解协调优化的研究策略 ,它是在各个匹配单元 (子系统 )和整个换热网络结构 (复杂系统 )之间进行优化协调 ,并获得换热网络的最优结构和各匹配单元的最优操作参数 .最后 ,通过一换热网络的最优合成 ,说明了该方法的应用前景     

考虑热集成的用水网络优化

提出了新的同时考虑间接传热和混合传热的热集成转运模型，并与用水网络超结构NLP模型结合以求取ΔTmin＝0℃时用水网络的公用工程目标。新转运模型与以往的模型相比变量数和约束方程数都大大减少。进一步，针对现有综合方法ΔTmin不可调的局限性，采用改进的换热网络转运模型，提出了区分处理混合传热和间接传热的综合方法。该方法不仅可以得到优化的公用工程费用和换热匹配数，而且与传统的方法相比可以调整ΔTmin，得到更合理的换热网络结构。算例表明，结合新转运模型的NLP模型与结合改进转运模型的综合方法都要优于以往的模型和方法。     

Simultaneous optimization approach for integrated water-allocation and heat-exchange networks

A systematic design methodology is developed in this work for simultaneously synthesizing the multi-contaminant water-allocation and heat exchange network (WAHEN) in any chemical process. Specifically, a modified state-space representation is adopted to capture the structural characteristics of the integrated WAHEN, and a mixed-integer nonlinear program (MINLP) is formulated accordingly to minimize the total annualized cost (TAC) of the network design. In the proposed mathematical programming model, not only all possible water reuse and treatment options are incorporated, but also the direct and indirect heat-exchange opportunities are considered as well. To enhance the solution quality and efficiency, a stochastic perturbation procedure is introduced to generate reliable initial guesses for the deterministic optimization procedures and also, an interactive iteration method is developed to guide the search toward a potential global optimum. Three examples are presented in this paper to demonstrate the validity and advantages of the proposed approach.     

Energy conservation in water allocation networks with negligible contaminant effects

A methodology to target the minimum energy requirement in water allocation networks where impurity concentrations do not play any significant role is proposed in this paper. The proposed methodology is mathematically rigorous and targets the minimum utility requirement satisfying the minimum approach temperature prior to the detailed design of both the water allocation network as well as the heat exchanger network. The proposed algorithm is presented through a tableau-based calculation procedure. A water allocation network design algorithm is proposed that guarantees the minimum energy targets obtained through the proposed energy recovery algorithm. The proposed methodology is also applied to inter-process heat integration between various water allocation networks.     

Heat Exchanger Network Integration Considering Flow Exergy Loss

This work describes a systematic procedure to integrate a heat exchanger network (HEN) considering heat and flow exergy consumptions. The flow exergy consumption by the HEN is calculated by means of pressure drop correlation and stepwise optimization. Case studies reveal that the flow exergy loss changes the two‐way trade‐off between the operating cost and the capital cost in the traditional method. The introduction of heat exergy loss adds the weight of energy cost by considering both the external utility consumption and internal heat exergy loss in the HEN, which benefits heat recovery and energy conservation at the cost of more area and investment. In contrast, the flow exergy loss shifts the balance to the capital cost by adding the cost relating to area in terms of flow frictional dissipation.     

Integrating compressors into heat exchanger networks above ambient temperature

Heat from compression processes is normally wasted to cooling water due to its low temperature or concerns about operability. The recoverable amount of heat can be enhanced by increasing the operating temperature of compressors. However, the compression work also increases under this condition. The integration of compressors into heat exchanger networks (HENs) is complex since both heat and work are involved, and the role of streams (as hot or cold streams), the utility demand, and the location of pinch points may change. A systematic graphical design procedure for above ambient HEN design including compressors was presented. The objective is to minimize exergy consumption to balance the complex heat‐work trade‐offs involved. Four theorems are proposed as the basis of the design procedure with certain well‐defined assumptions. It is found that the compression should be performed at pinch or ambient temperatures to achieve minimum exergy consumption. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3770–3785, 2015     

功热交换网络综合的研究进展

功和热是化工工业中使用能源的两种最主要方式,由于流股压力、温度操作需要消耗大量的功热,因此研究功热的协同利用对于提高过程整体能源利用率具有重要的意义。本文首先概述了基于热力学分析的功热交换网络综合的研究情况,以系统?耗最小为目标探讨压缩机、膨胀机优化配置与换热网络用能瓶颈的耦合关系,揭示了功热协同利用的作用机制。然后系统地总结了以年度总费用最小为目标的数学规划模型综合功热交换网络的研究进展,探寻压力操作路径、流股功/热交换匹配、公用工程消耗量及设备投资之间的有效权衡;最后对后续研究进行展望,指出可进一步探究考虑流股冷热性质判定的功热交换网络同步综合、公用工程系统优化与功热交换网络同步设计的耦合等。