并联连续再生/再循环的多杂质间歇用水系统优化方法

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。     

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。     

多杂质体系间歇过程用水网络优化

对多杂质体系完全间歇过程用水网络优化进行了研究,建立了用水网络超结构和非线性规划数学模型,利用中间储罐跨越时间约束,设置用水过程流量上下限以加速收敛。首先确定关键杂质,并将关键杂质浓度最大的水源直接排往废水,获得简化的用水网络超结构;其次,运用GAMS求解,得到最小新鲜水量、废水量、中间储罐数目及优化的用水网络结构。实例研究证明本文提出的方法可行,并能以较少周期获得优化的网络结构,同时可以减少中间储罐数目。     

河源电厂精处理系统在3种给水工况下的运行

河源电厂2×600 MW超超临界机组先后采用AVT(R)、AVT(O)及OT给水处理方式运行。简单介绍了两台机组的凝结水精处理系统和水汽品质,对精处理系统在3种工况下混床的运行周期、再生用水和酸碱消耗量进行了计算和对比。数据表明,AVT(R)和AVT(O)方式下混床运行周期以及再生消耗量基本相同,而OT方式下混床运行周期延长至AVT方式的2倍以上,其再生用水和药耗量减至45%以下。此外,机组加药量的比较结果也说明,OT方式加药量少,更为节省药品和安全环保。     

煤化工废水零排放的工程运行及结垢离子脱除的分析研究

分析了煤化工废水零排放实施的必要性及可行性,以某年产200万t合成氨、350万t尿素项目为例,探讨了废水零排放工程的运行情况,以及结垢离子的脱除技术。介绍了回用水处理和浓盐水处理的工艺流程和运行中存在的问题,运行调试中发现二价离子的去除在煤化工废水零排放中起着至关重要的作用。针对运行中存在的问题采取了改进措施,主要包括蒸发系统连续出盐、离子交换器实时监测确保系统产水二价离子的精度、保证再生液系统的稳定运行,以及对操作人员的严格规范培训。改进后零排放系统的二价离子受到了控制,末端蒸发系统的结垢清洗频率大幅降低,从而大幅度提高了零排放系统运行稳定性。     

线路板与电镀废水处理与回用工艺

印制线路板生产废水和电子电镀废水排放量大,废水中污染物种类多、成份复杂。文章介绍了废水的处理技术和中水回用工艺。整套工艺的运行实践表明：该工艺切实可行,处理出水水质达到《广东省水污染物排放限制》（DB44／26-2001）第二时段的一级标准,再生回用水水质优于自来水,可满足生产线用水水质要求。     

基于线性规划的单杂质间歇过程用水最小化

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。     

黄金冶炼废水处理工艺优化及系统改造

针对某黄金冶炼厂的废水处理系统存在的问题,通过工艺优化并增设相应的处理装置等措施对废水处理系统进行改造升级,解决了现场操作环境差、回用水硬度大、设备易腐蚀等问题。改造后的废水处理系统运行正常,废水稳定达标排放。     

间歇逆流清洗的理论计算(上)

间歇逆流清洗是指用一系列静止水槽进行清洗,到一定阶段把第一个或前几个槽中的水抽去,将后面槽子中的水依次泵入前面的槽子,再在空出来的槽子中补充清水。间歇逆流清洗可以大大节约清洗用水和减少废水体积,具有重要的经济和社会效益。使用间歇逆流清洗,关键是要合理地选择清洗槽的数目和换水的周期。清洗槽的数目多,清洗效果好,换水周期可以延长,但操作不方便,生产线要延长,效率降低。清洗槽过少则达不到清洗要求。当清洗槽数目确定之后,从节约用水、减少废水体积及操作方便的角度看,换水周期越长越好。但是,换水周期越长,清洗槽中积累的污物越多,换水周期过长将达不到清洗要求。     

最小化新鲜水量与废水处理量的图形方法

水分配网络由回用、再生和废水处理3个相互作用的子系统构成。设计水分配网络需考虑质量负荷固定和流量固定两类用水操作模型。目前,兼顾两类用水操作的图形方法对水分配网络的研究局限于一个或两个子系统的设计,而缺少一种能同时处理3个子系统的方法。本文用新的方法合成了反映用水网络水源盈亏情况的总组合曲线,并由此得到最小废水量和新鲜水量。为考虑废水再生情况,提出通过用再生水线和废水线合成废水排放线的方法求解再生情况下的最小新鲜水量。同时,根据总组合曲线得到了废水组合曲线,求得最小废水处理量。实例表明,本文所提方法可在具体网络设计前,在同一浓度-质量负荷图中确定单杂质水分配网络的各目标参数,且简便易行。     

用水系统的近优化运行及其操作窗口获取方法

针对用水系统优化设计和操作的可靠性问题,本文以用水过程进出口浓度为噪声因子、以近优化用水目标为控制因子,提出了用水系统近优化设计和操作的操作窗口分析方法及其实现步骤;建立了用水系统近优化操作参数获取的数学模型和搜索策略,并通过计算实例阐明了所提出方法的可行性。本文提出的分析方法为用水系统的近优化设计和操作可靠性的分析提供了理论分析基础。     

A graphical technique for the design of water-using networks in batch processes

This paper presents a graphical technique for the design of water-using networks in batch plants. Water integration is achieved by exploiting all possibilities of water reuse/recycle to minimize not only freshwater consumption, but also wastewater generation. Since time limitation for unmatched operating periods may be the primary barrier to the integration in batch processes, the installation of storage facilities is quite common to enhance the water recovery. For that reason, the cost in terms of storage facilities becomes another issue to be considered. This work is focused on network design, like the second stage of conventional pinch analyses. Some useful concepts and principles addressed in literatures are adopted to help the design of batch water network and to ensure the maximum recovery, thus the utility usage, the network structure and the storage policy can be obtained through the analysis. Once the freshwater expenditure is determined, workable ways are sought to cut the number of storage tanks and they also reduce the network complexity. In the context of this paper, a hybrid system that includes different type of water-using operations with distinct operating modes is taken into account to display the versatility of proposed approach. Furthermore, considering the fact that sometimes water reuse/recycle between certain operations is not allowed to prevent operational problems, the action of network design should be more deliberate owing to additional restraints. Therefore, the potential for water integration may be diminished, which means a less amount of water recovery. Finally, an illustrative example is provided to amplify the application of proposed approach. Like most graphical techniques, the presented work is restricted to a single key contaminant.     

基于截断器半连续操作的间歇过程性质集成

生产过程对水质的要求不仅体现于杂质浓度，还包括毒性、pH、化学需氧量等流股性质，因此仅以杂质浓度作为水源使用及废水排放依据进行用水过程设计无法满足生产要求，有必要在用水网络综合过程中考虑多种性质的同时集成。针对间歇过程性质集成问题，在考虑环境约束的基础上，以最小年度总费用为目标，建立了包含半连续操作性质截断器的用水网络超结构。其中，截断器在不同时间间隔内可以按不同操作速率运行；在截断器前后分别设置缓冲储罐以满足水源水阱的间歇操作要求，允许前置缓冲储罐中的水源不经过截断器直接回用至水阱。算例计算结果表明，本文方法可以有效降低年度总费用，同时减少截断器数量，验证了本文方法的有效性和优越性。     

Synthesis of Water Utilization System Using Concentration Interval Analysis Method （Ⅱ） Discontinuous Process

The first part of the series of this article proposed a systematic method for the synthesis of continuous water-using system involving both non-mass-transfer-based and mass-transfer-based operations.This article,by extending the method,proposes a time-dependent concentration interval analysis（CIA）method to solve the problems associated with the synthesis of discontinuous or batch water-using systems involving both non-mass-transfer-based and mass-transfer-based operation.This method can effectively identify the possibility of water reuse and the amount of water reused under time constraints for minimizing the consumption of freshwater in single or repeated batch/discontinuous water-using systems.Moreover,on the basis of the heuristic method adapted from concentration interval analysis method for the continuous process network design,the network design for the discontinuous or batch process can be obtained through the designs for every time interval.Case study illustrates that the method presented in this article can simultaneously minimize the freshwater consumption in single or repeated batch/discontinuous water system and can determine a preferable storage tank capacity for some problems.     

基于浓度间隔分析的用水系统集成(Ⅱ)不连续过程

The first part of the series of this article proposed a systematic method for the synthesis of continuous water-using system involving both non-mass-transfer-based and mass-transfer-based operations.This article,by ex- tending the method,proposes a time-dependent concentration interval analysis(CIA)method to solve the problems associated with the synthesis of discontinuous or batch water-using systems involving both non-mass-transfer-based and mass-transfer-based operation.This method can effectively identify the possibility of water reuse and the amount of water reused under time constraints for minimizing the consumption of freshwater in single or repeated batch/discontinuous water-using systems.Moreover,on the basis of the heuristic method adapted from concentra- tion interval analysis method for the continuous process network design,the network design for the discontinuous or batch process can be obtained through the designs for every time interval.Case study illustrates that the method presented in this article can simultaneously minimize the freshwater consumption in single or repeated batch/discontinuous water system and can determine a preferable storage tank capacity for some problems.     

A heuristic design method for batch water-using networks of multiple contaminants with regeneration unit

This work develops a heuristic method for the design of batch water-using networks of multiple contaminants with regeneration unit based on the concepts of concentration potential. A water-using network involving regeneration unit can be formed by adding the regenerated stream(s) into the network involving reuse only. In the design procedure of the network operated in a single batch mode, time is taken as the primary factor and concentration potentials as the secondary one. For the networks operated in a repeated mode, the design procedure is similar to that for continuous processes, besides designing the storage tanks with the rules proposed. Continuous regeneration unit is selected in this work. With the proposed method, the network structure corresponding to the minimum freshwater consumption can be obtained. It is shown that the method proposed in this article is simple, effective and has clear engineering meaning.     

逐步线性规划法求解废水最小化问题

对用水过程的优化设计即废水最小化问题进行了研究 ,提出了操作水源和操作序列的概念 .分别对单组分再利用、多组分再利用及单组分再生再利用问题 ,提出了逐步线性规划的解算方法 .新方法首先依据规则将操作对贫流的要求进行分段排序 ,然后按操作序列逐级进行富流和贫流水源的优化匹配 ,最终完成用水过程的设计 .给出了 4个实例 ,计算结果表明本文方法是有效和简便易行的     

Pinch multi-agent genetic algorithm for optimizing water-using networks

A new genetic algorithm, pinch multi-agent genetic algorithm (PMAGA), is developed for optimizing water-using networks. All agents are fixed on a lattice, and they will compete or cooperate to increase their energy. On the other hand, agents can also increase their energy with knowledge. For single contaminant water-using systems, PMAGA and other algorithms as well as Lingo can find the same minimum freshwater consumption. For multiple contaminants systems, it can find the same or better results in case studies. Moreover, PMAGA is more efficient for much shorter computational time compared with other algorithms, and furthermore, it can yield many water-using networks consuming the same minimum freshwater but with different configurations, whereas Lingo yields only one network. These alternative configurations give more options for industries.