共查询到17条相似文献,搜索用时 62 毫秒
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水级联法确定间歇用水过程的夹点及废水最小化 总被引:1,自引:1,他引:0
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。 相似文献
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对间歇化工过程的单杂质用水网络提出了以新鲜水量最小为目标的优化设计方法。该方法对间歇过程的每个操作假定为一个操作接一个储罐,对所有操作按出口浓度从小到大排序,避免了高浓度水回用到低浓度水的操作中,去掉了用水网络中多余的连接,构造了用水网络超结构。该超结构可以表述为一个线性规划模型。通过GAMS求解该模型得出每个操作周期的最小新鲜水量,并通过证明得出该最小用水量随操作周期增加最终不再变化。该方法可以用作有、无中间储罐间歇过程用水网络综合,实例计算结果表明该方法是可行的,与其他方法相比更简单。 相似文献
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This paper introduces a non-iterative algorithmic procedure to design water utilization networks with multiple contaminants in process plants. According to the water pinch analysis rules, the processes in water utilization systems were first divided into three groups, then water-supply priority algorithm was proposed. The results of case studies showed that the water networks designed by this method gave water consumption lower than that estimated by other approaches. In addition, the procedure was subiect to no limitation on the problem scale. 相似文献
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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。 相似文献
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水夹点分析与数学规划法相结合的用水网络优化设计 总被引:10,自引:8,他引:10
提出了水夹点分析和数学规划法相结合的用水网络最优设计法。水夹点分析基于对过程用水的理解,获得新鲜水用量目标并给出用水网络设计的基本规则。在此基础上建立过程使用新鲜水、排放废水和回用的各种可能匹配方案的用水网络超结构及其MINLP模型。既避免了用水夹点综合设计用水网络得不到真正意义上的最优解,又在一定程度上防止超结构规模过大,MINLP维数太高,求解困难。采用通用代数建模系统GAMS得到用水网络最优设计方案。文献中的应用实例表明,本文所提方法可充分发挥水夹点分析确定新鲜水用量或回用结构的简洁实用性和超结构MINLP寻求最佳方案的优点。 相似文献
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Chun Deng Xiao Feng Denny Kok Sum Ng Dominic Chwan Yee Foo 《American Institute of Chemical Engineers》2011,57(11):3085-3104
A new process‐based graphical approach (PGA) is presented for the simultaneous targeting and design of water network. The PGA is extended from the limiting water profile which was developed for flow rate targeting for a water network. Via PGA procedure, apart from locating the minimum freshwater and wastewater flow rate targets, the water network that corresponds to the minimum flow rate targets is also synthesized simultaneously. The proposed approach handles both fixed load (including operations with water loss and/or gain) and fixed flow rate problems equally well. In addition, the approach can be used to synthesize direct reuse/recycle, regeneration reuse/recycling, and total water network. Furthermore, the proposed approach is applicable for water network with multiple freshwater sources. Three literature examples are presented to illustrate the proposed approach. © 2011 American Institute of Chemical Engineers AIChE J, 2011 相似文献
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Water network with regeneration schemes (e.g., regeneration reuse, regeneration recycling) can reduce freshwater consumption further than water network merely with direct reuse. Regeneration reuse, compared with regeneration recycling, can additionally avoid unexpected accumulation of contaminants. Owing to these features, process decomposition can help to reduce freshwater usage and wastewater discharge of regeneration reuse water systems and achieve the results, which graphical method delivers. In this article, the effect of decomposition on water‐using process and further on regeneration reuse water system is briefly analyzed on the concentration‐mass load diagram. Then a superstructure and three sequential mathematical models, which take process decomposition into account, are in turn developed to optimize single contaminant regeneration reuse water systems. By several examples, the reliability of the models is verified. Moreover, several decomposition strategies are summarized to realize the regeneration reuse water network, which attains the targets from graphical method. The results indicate that postregeneration concentration has a major impact on the scheme of process decomposition. © 2009 American Institute of Chemical Engineers AIChE J, 2009 相似文献
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运用水夹点技术,对某石化企业进行用水网络优化研究.在流量恒定和流量改变两种条件下,对某石化企业9个用水操作原有用水网络进行初始设计和优化改进.结果表明,在流量恒定和流量改变条件下,通过用水网络初始设计节约新鲜水用量分别为19.17%和22.87%,对用水网络的初始设计和优化可简化用水网络,回用管路数分别由11条减少为6条和5条,优化后的用水网络分别节约新鲜水用量18.79%和22.47%.水夹点技术在工业用水节约和废水减量方面具有实用价值和较好的应用前景. 相似文献
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Water-oxygen pinch analysis is an effective method to decrease the wastewater quantity and improve the wastewater quality. But when multiple-contaminants are present, the method is difficult to be carried out. In this paper, the method that combines water-oxygen pinch analysis with mathematical programming is proposed. It obtains the general optimal solution and leads to the reuse stream that cannot be found only by pinch analysis. The new method is illustrated by an example, and the annual cost is reduced by 8.43% compared with the solution of literature. 相似文献
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Water distribution networks (WDN) are vulnerable to either intentional or accidental contamination. In order to protect against such intrusions, effective and efficient online monitoring systems are needed. Due to cost and maintenance reasons, it is not possible to locate sensors at each and every potential intrusion point. In this work, we design minimal sensor networks which satisfy the two important properties of observability (ability to detect an intrusion) and identifiability (ability to identify the point of intrusion). Based on the hydraulic analysis of the network, a bipartite graph is constructed between intrusion points and the corresponding nodes that can potentially be affected by the contaminant. The problem of sensor network design is converted to a minimum set cover problem on the bipartite graph, and is solved using a greedy heuristic algorithm. The proposed method is illustrated using a medium scale urban WDN. 相似文献
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Targeting and design of water networks for fixed flowrate and fixed contaminant load operations 总被引:6,自引:0,他引:6
Ravi Prakash 《Chemical engineering science》2005,60(1):255-268
Water-using processes are typically modeled as either fixed flowrate operations or fixed contaminant load operations. A new method for targeting the minimum freshwater and pinch in a single-contaminant water network is proposed, which can be applied to both kinds of operations. The method consists of plotting separate source and demand composites with flowrate as the horizontal axis and contaminant load unusually as the vertical axis. It is elegant, non-iterative, and can handle hybrid problems where both kinds of operations coexist.To design minimum freshwater networks for fixed flowrate problems, an algorithm is presented based on a newly developed principle of nearest neighbors. The principle simply states that the source streams to be chosen to satisfy a particular water demand must be the nearest available neighbors in terms of contaminant concentration.To design minimum freshwater networks for fixed contaminant load problems, the nearest neighbors algorithm is applied to process units that lie across the pinch. Units that lie entirely on one side of the pinch are satisfied by the cleanest source available on that side of the pinch. In other words, below-pinch units are satisfied by freshwater and above-pinch units are satisfied by the cleanest available stream above the pinch. Designs based on this methodology, apart from meeting the minimum freshwater target, also minimize the water flowing through the process units resulting in reduced network capital cost. 相似文献