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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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为了有效地减少多杂质间歇用水系统的新鲜水消耗量和再生处理量,针对多杂质间歇过程用水网络提出连续操作并联再生处理单元水网络结构模型及其优化设计方法。通过在用水网络中设置中间储罐和再生单元以实现对不同水质废水并联分质处理,建立了减少用水系统的新鲜水用量和再生水量以及废水排放量的数学规划模型,采用GAMS软件对一个实例进行求解。计算和分析表明:提出的水网络结构与优化设计方法可有效地解决按水质对废水进行并联处理的间歇用水系统,使系统的新鲜水用量和再生水流率同时达到最小。 相似文献
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棉浆粕生产过程中会产生大量废水,废水具有水量大、污染物含量高、悬浮物多、色度高等特点。对废水污染的防治,首先是立足生产用水的循环使用,降低废水排量,而后对废水采用相应的处理技术。介绍了对棉浆粕废水的几种处理方法。 相似文献
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印刷线路板废水处理与回用工艺 总被引:2,自引:0,他引:2
印制线路板工业废水排放量大,废水中污染物种类多、成份复杂。根据各工序污染物的种类以及生产工序清洗用水标准,将废水分为三类进行处理。介绍了废水处理和一般废水回用深度处理工艺。将该工艺应用于印制线路板工业废水处理,结果表明,废水回用率达到或接近60%,电导率低于150μS/cm,pH=6.5~8。再生回用水水质优于自来水,可满足生产线用水水质要求。 相似文献
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Shell煤气化废水处理及回用 总被引:1,自引:0,他引:1
Shell煤气化工艺过程产生的废水具有高SS、高CODCr以及污染物成分复杂的特点,其中主要的污染物有氰化物、NH3-N、硫化物以及苯酚等。通过预处理(曝气-絮凝沉降)、深度氧化以及双膜处理的工艺对Shell煤气化废水进行处理,考察了各工艺段的最佳运行条件。试验结果表明,在最优运行条件下,该处理工艺出水达到GB 8978—1996《污水综合排放标准》的要求,同时通过阻垢及缓蚀试验结果确定,工艺出水达到GB 50050—2007《工业循环冷却水处理设计规范》中工业循环水用水标准的要求,可以回用至循环冷却水系统。 相似文献
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Shell 煤气化工艺过程产生的废水具有高 SS、高 CODCr 以及污染物成分复杂的特点,其中主要的污染物有氰化物、 NH3-N、硫化物以及苯酚等。通过预处理(曝气-絮凝沉降)、深度氧化以及双膜处理的工艺对 Shell 煤气化废水进行处理,考察了各工艺段的最佳运行条件。试验结果表明,在最优运行条件下,该处理工艺出水达到GB 8978-1996《污水综合排放标准》的要求,同时通过阻垢及缓蚀试验结果确定,工艺出水达到 GB 50050-2007《工业循环冷却水处理设计规范》中工业循环水用水标准的要求,可以回用至循环冷却水系统。 相似文献
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热电厂是用水大户,化水工艺用水来自地表水,地表水首先通过纤维过滤器和一体化净水器进行预处理,预处理工艺中产生约200t/h的反洗废水.为提高水资源利用率,降低新鲜水取用量,实现工艺水回收再利用,本文将首先分析该反洗废水的产生情况,并对废水成分进行分析,随后将这部分废水通过全自动净水设备进行处理,使之达到原水水质标准后回... 相似文献
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当前对水回用网络的研究,主要集中于在用水过程情况确定条件下构造新鲜水量最低的用水网络,忽视了用水过程的变化性.本文以配合法构造用水网络,每一用水过程入水以新鲜水、低污染回用水和高污染回用水配合获得,使各过程进水流量比尽可能趋近1,各过程按出口极限浓度由低到高依次运算.该方法以过程为运算单元,所以可针对具体过程,通过即时修改可回用水的流量、浓度等运算参数实现条件改变下的用水网络构造,同时有利于实现用水网络的在线优化和成本控制.最后通过实例说明了该方法的有效性. 相似文献
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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。 相似文献
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引入再生循环的最优水系统可以最大限度地节约新鲜水的用量和减少废水的排放,是当前节水技术研究的重点。用水系统引入再生过程后,极限供水线会发生变化,从而水系统夹点个数以及位置都可能会发生变化。运用前人总结出的再生循环过程最佳供水线的构造方法,分析影响引入再生过程后夹点位置变化的因素,发现引入再生过程前后夹点位置的变化情况与以下因素有关:极限复合曲线上的凹点位置以及凹向极限供水线的程度和最高浓度用水单元水流率与新鲜水流率的关系,并分析得出夹点位置的变化规律,从而为用水网络的分析和设计提供理论性的指导。 相似文献
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A sequential three-step programming method is proposed for determining the minimum flowrate of fresh water and corresponding regenerated water in water-using system of single contaminant with regeneration reuse.In step 1, a programming with the objective of min fws is used to determine the minimum flowrate of fresh water,in which the mathematical representation is a mixed integer nonlinear programming (MINLP1). Then under the same constraints with step 1, a programming with the objective of min freg in step 2 and a programming with the objective of rain Cr in step 3 are subsequently used to determine the minimum flowrate of regenerated water and the minimum inlet concentration to regeneration process corresponding to the minimum flowrate of fresh water based on step 1. The method is easy to apply because we only need to change the objective function but keep the constraints constant to go along the following steps after step 1. In addition, the relationship between the fresh water flowrate required, fws, and inlet concentration to regeneration process, Cr, is investigated. It is found that there exist three relationships between fws and Cr, which indicate three possibilities for Cb: below the pinch, above the pinch or at the pinch. Therefore, a new conclusion is drawn, which differs from that “regeneration of water at pinch minimizes fresh water flowrate“ derived in literature and indicates that in some cases, regeneration at other point also minimizes fresh water flowrate. 相似文献
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On the use of graphical method to determine the targets of single-contaminant regeneration recycling water systems 总被引:2,自引:0,他引:2
Water system integration with regeneration recycling can reduce freshwater consumption and wastewater discharge to the maximum extent. In this paper, by analyzing the limiting composite curve of a single-contaminant water system, a method is proposed to construct the optimal water supply line for regeneration recycling. Accordingly the targets for regeneration recycling water systems are obtained. The targets in sequence are the minimum freshwater consumption (the minimum wastewater discharge), the minimum regenerated water flowrate, and the optimal regeneration concentration. The post-regeneration concentration is taken to be fixed in the sequential targeting procedure. The interactions of these targets are analyzed, and formulas for calculating these targets are proposed. The results show that for a single-contaminant regeneration recycling water system, the minimum freshwater consumption is determined by the shape of the limiting composite curve below the post-regeneration concentration. The optimal regeneration concentration is defined as the minimum regeneration concentration at the minimum freshwater consumption and the corresponding minimum regenerated water flowrate. The minimum regenerated water flowrate and the optimal regeneration concentration are both related to the geometrical features of the limiting composite curve of the water-using system and to the post-regeneration concentration. The optimal regeneration concentration has no direct relationship with the pinch concentration. 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