基于粒子群优化算法的水分配网络系统综合的最优化研究

The problem of optimal synthesis of an integrated water system is addressed in this study, where water using processes and water treatment operations are combined into a single network such that the total cost of fresh water and wastewater treatment is globally minimized. A superstructure that incorporates all feasible design alterna- tives for wastewater treatment, reuse and recycle, is synthesized with a non-linear programming model. An evolutionary approach--an improved particle swarm optimization is proposed for optimizing such systems. Two simple examples are .Presented.to illustrate the global op.timization of inte.grated water networks using the proposed algorithm.     

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。     

低温位废热回收与液化天然气冷能利用的集成研究

Two novel thermal cycles based on Brayton cycle and Rankine cycle are proposed, respectively, which integrate the recovery of low-level waste heat and Liquefied Nature Gas （LNG） cold energy utilization for power generation. Cascade utilization of energy is realized in the two thermal cycles, where low-level waste heat,low-temperature exergy and pressure exergy of LNG are utilized efficiently through the system synthesis. The simulations are carried out using the commercial Aspen Plus 10.2, and the results are analyzed. Compared with the conventional Brayton cycle and Rankine cycle, the two novel cycles bring 60.94% and 60% in exergy efficiency, respectively and 53.08% and 52.31% in thermal efficiency, respectively.     

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.     

考虑再生操作的间歇过程用水网络优化

当前,水资源短缺与污染问题日益严重,废水再生后回用对节约水源和保护环境具有重要的意义。针对间歇过程,为了合理利用不同品质的过程水源,实现用水系统的最大水回用,本文建立了一个包含水源-水阱、水源-中间储罐-水阱、水源-连续再生体系-水阱与水源-废水处理系统的用水网络超结构,基于连续时间模型建立数学模型,并采用多目标分步法依次优化新鲜水用量、再生单元的再生速率以及中间储罐数目,最终得到新鲜水消耗量以及废水排放量最小的最优用水网络结构。同时,为贴近实际生产中的多操作周期过程,本文针对用水系统从启动周期到稳定周期的全过程,进行了用水网络的设计、分析与优化。最后通过算例计算,验证了本文所提方法的合理有效性。     

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。     

最佳间歇水循环网络的合成和时序安排

This work develops an optimization-based methodology for the design and scheduling of batch water recycle networks. This task requires the identification of network configuration, fresh-water usage, recycle assignments from sources to sinks, wastewater discharge, and a scheduling scheme. A new source-tank-sink representation is developed to allow for storage and dispatch tanks. The problem is solved in stages by first eliminating scheduling constraints and determining minimum usage of fresh water and wastewater discharge. An iterative procedure is formulated to minimize the total annual cost of the system by trading off capital versus operating costs. The work overcomes limitations in previous literature work including restricted recycle within the same cycle, lumped balances that may not lead to feasible solutions, and unrealistic objective functions. A case study is solved to illustrate the usefulness of the devised procedure.     

通过数学规划方法设计具有混合结构的水回用网络

A new design method for a water-reusing network, with a hybrid structure, to reduce the complexity of the network and to minimize freshwater consumption, is proposed. The unique feature of the methodology proposed .in this article is to control the complexity of the water network by regulation of the control number in a water-reusing system. It combines the advantages of a conventional water-reusing network and a water-reusing net work with internal water mains. To illustrate the proposed method, a single contaminant system and a multiple contaminant system serve as examples of the problems.     

能量集成用水网络设计方法研究

采用数学规划方法,分别用分步设计方法和同步设计方法对单杂质能量集成用水网络进行了研究,根据实例研究结果进行对比,说明同步优化设计法比分步设计法更为准确和有效。     

考虑环境及处理单元流股回用的多性质用水网络集成

水资源的日益匮乏和更为严格的废水排放法律法规促使过程工业必须重视节水减排问题,而传统的用水网络综合仅将杂质浓度作为约束物料回用的限制因素,忽略流股的性质或功能对流股回用的影响,不足以反映实际的工业生产要求。因此,开展用水网络的多性质集成问题研究具有重要的现实意义。本文在考虑环境问题的多性质用水集成超结构模型基础上,增加了对废水流股性质处理中部分流股依次回用给阱单元使用的过程。该方法以最小年度总费用为目标函数,建立了考虑环境和过程流股性质的直接回用及经过处理单元后流股回用的混合整数非线性规划(MINLP)模型,并将其用于实例计算,结果表明本文方法在降低年度总费用的同时还减少了新鲜水使用量及废水排放量,验证了本文方法的有效性及优越性。     

间歇过程单杂质用水网络设计

提出了一种利用时间-纯度两维用水图进行用水网络设计的方法,分别提出了无中间储罐和有中间储罐的设计规则。该方法把水的纯度作为一维,把时间作为另一维,从而更好地同时描述间歇用水过程的时间特性和杂质特性。它首先通过水级联分析技术确定间歇过程用水网络的夹点及最小公用工程,然后利用时间-纯度图和设计规则来合成用水网络,对有储罐的情况,确定了储罐的数量与容量,最后利用时间-水网络图描述了所合成的最优间歇过程用水网络,并探讨了用水过程流量对网络的影响。通过文献实例计算,表明该方法简单、直观、有效。     

浅谈污水综合利用技术途径

结合运行实例,从污水回用和热量回收两方面介绍了污水综合利用的技术途径:一是深度处理后进行回用;二是利用水源热泵技术回收热能.     

Simultaneous integration of water and energy in heat‐integrated water allocation networks

This article proposes a new methodology for simultaneous integration of water and energy in heat‐integrated water allocation networks (WAHEN). A novel disjunctive model is first developed to determine an optimal water allocation network (WAN) where water and energy are integrated in one step. Based on the optimal WAN, a detailed heat exchanger network (HEN) to satisfy the utility target is then synthesized. Although the final network structure is obtained through two steps, the targets of freshwater and utility are optimized simultaneously. The proposed method has specific advantages. First of all, it can capture a tradeoff among freshwater usage, utility consumption, and direct heat transfer by nonisothermal mixing. Second, it can greatly reduce the complexity of subsequent HEN design. Finally, it is effective for simultaneous water and energy integration in large‐scale WAHEN systems. The advantages and applicability of this new method are illustrated by three examples from literature. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2202–2214, 2015     

水夹点分析与用水网络优化设计方法

水夹点技术作为一种有效的优化方法在用水网络优化、水源节约及废水减量等方面应用,能收到良好的经济效益和环境效益.作者介绍了水夹点技术的基本原理、应用实例以及进一步网络优化设计方法.     

水级联法确定间歇用水过程的夹点及废水最小化

利用水级联分析法对间歇过程用水网络进行研究,确定过程的用水夹点及最小新鲜水用量和最小废水排放量,提出了间歇用水过程的全局夹点的概念,考虑了用水过程的流率限制,在水级联表格中用流率替代了传统水级联分析法中的传质量,识别过程中每个时间段的局部夹点及公用工程目标,通过全局夹点和局部夹点的比较,指出过程的用水瓶颈,设置储罐打破瓶颈,使用水网络公用工程目标最小化。通过实例对水级联分析法进行了详细的阐述,计算结果与文献一致,表明该方法是一种易于理解、直观且简便有效的确定间歇过程用水网络的夹点及最小公用工程的方法。     

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。     

实施清污分流提高水资源利用率

介绍甘肃瓮福化工有限责任公司工艺水使用不合理、含磷废水外排严重,造成水耗、磷耗高的问题,通过实施用水分厂小循环、公司大循环、清污分流,并强化管理,水资源利用率提高,年节约成本104万元,回收磷酸一铵产品900 t、P2O5 432 t.     

基于多线程运行控制的高效节能型净水工艺

华北地区某净水厂以当地水库水为水源,原水受到有机物污染,水质受季节影响变化较大。为应对上述水质问题采用高密度沉淀池—V型滤池—超滤—臭氧加活性炭吸附的工艺流程,但该工艺流程较长,运行能耗较高。针对季节和水质变化,以供水安全可靠为前提,高效节能为目标,提出了水厂运行的多线程工艺流程。经节能评估,运行改进后可节能23.96%。