供水管网阀门的选型与维护

针对某厂外部供水及厂区供水管网中阀门存在的问题进行了分析,在阀门的选型与维护上取得了一些经验。     

地下供水管网普查及泄漏检测

针对种种原因造成的地下管网数据资料缺失,应用先进的地下管线探测技术,对地下管线位置、埋深进行探测,结合RTK(实时动态差分)技术,对地下管网及其周围厂房建筑位置进行厘米级精确测绘,提高化工企业地下管网管理水平。通过应用相关法对地下管网的泄漏检测结果表明,阀门的填料泄漏是供水管网泄漏的主要原因。     

油田管网应急指挥关键技术研究

采用分层叠加、坐标转换、穿孔管网关联阀门和地图数据分时修正技术构建了油田应急指挥系统,其中坐标转换技术实现了经纬度到西安80坐标的转换,为穿孔管网关联阀门定位事故点做好了准备;穿孔管网关联阀门技术通过管网与阀门之间的拓扑关系实现了管网与阀门之间的智能查询,完成对应急事件的处理;地图数据分时修正技术实现了地图文件的修正维护。通过应用这4种技术,在最短的时间内达到地图上事故点定位、关联到离事故点最近的阀门和调用应急响应预案处理事故管网的目的,解决了以往管网、阀门等基础设施的具体位置靠人工经验定位的问题,同时在对地图数据维护时,实现了地图数据的安全性和统一性。     

管网消毒、清洗、非开挖修复诊断与评估技术

随着城镇化和水厂集约化发展,供水管网规模逐步扩大,输配距离增加,停留时间延长,水质在管网输配过程中发生一定程度的恶化。面对高品质饮用水的供水目标和要求,亟需加强供水管网水质安全保障能力。在"十二五"水专项供水管网水质安全多级保障与漏损控制技术研究与示范的研究成果基础上,通过协同管网多级消毒、冲洗、修复,集成供水管网水质调控技术,有效保障供水管网运行安全,为供水企业提供管网运行维护和管理的措施及依据。     

变频节能技术在油田供水中的应用

在油田注水注水过程中,输水泵是满足注水站有足够水源的源设备。在实际生产中,日输水量是一个波动较大的参数,输水量及外输压力的大小,必须靠控制出口阀门来保证供水管网的压力和流量,同时电动机又长期处于高耗能状态运行,这样不但因为泵压过高而不利于机泵运行,而且还会造成大量的能源损耗。然而,变频装置通过供水管网的流量以及压力参数的限定,使得供水压力自动调节水量,这样不仅使机泵能耗减少,还大大节约了电能,这对实现油田的节能耗损有着重要的价值。     

供水管网工程造价控制及可持续发展探讨

在市场经济下,供水管网工程造价控制是相关企业提高市场竞争力的重要途径。因此,文中基于供水管网工程概述,以及影响供水管网工程造价控制的主要因素,对供水管网工程造价控制可持续发展策略进行简单分析。以此,提高供水管网工程质量,为社会经济建设做贡献。     

管网漏损控制技术在独立计量区的应用

通过选择独立计量区现场测试以及供水管网漏失监测系统的应用,探求适合于小区控制供水管网漏损的研究方法,实现供水管网有效控制,减少管网漏损率。基于GIS地理信息系统平台实现管网动态管理,保障城市供水管网安全运行,取得良好经济效益和社会效益。     

宝钢供水管网智能化信息管理研究与应用

国内钢铁企业供水管网管理落后,自动化程度不高,缺乏管网信息化管理平台。随着对管网安全性和成本核算要求的不断提高,供水管网的管理问题日趋突出。作者通过对钢铁企业供水管网的信息管理和应用的研究,设计并开发了供水管网智能化信息管理系统。该系统使用AutoCAD建立管网模型和地形图系统．通过SQL Server数据库实现数据的存储和管理。经过实际应用,证明该系统可以大大丰富供水管网系统的管理功能,提高管理效率。对钢铁企业和其他相关行业,提高供水管网的管理水平具有较大的实际意义。     

基于人工神经网络的供水管网压力管理探索

供水管网的压力管理对实现按需供水、减少漏损和降低能耗具有重要的意义,实现压力管理的重要手段是对供水管网进行数学建模和数值仿真。但是,供水管网是非常复杂的大型非线性系统,按照传统的微观建模方法建立的供水管网模型往往精度不够,其数值求解效率也低,不适合基于这样的模型进行压力管理。该文提出了一种基于人工神经网络的供水管网压力管理的方法,即利用人工神经网络在供水管网的压力和流量之间建立非线性模型,并利用该非线性模型进行供水管网压力管理,而供水管网的压力管理则通过最优化问题的数值求解来实现。试验表明在不降低流量的情况下,供水的水压可降低1％。这对于减少供水管网的漏损、降低产销差率以及减少能耗具有重要的意义。     

浅谈分区计量(DMA)主动漏损控制的发展

国内许多的供水企业花费大量的资金不断地完善供水管网,主要是为了解决供水能力不足、供水厂供水质量差、供水产销差大等影响供水企业发展的难题。随着国务院"水十条"、《城镇供水管网漏损控制及评定标准》的颁布,明确规定:城镇供水管网基本漏损率分为两级,一级为10%,二级为12%,到2017年,全国公共供水管网基本漏损率达到二级标准,到2020年达到一级标准。分区计量(DMA)是通过安装计量仪表将供水管网分为若干独立供水区块,对独立供水区块入口进行连续的流量和压力监测,供水企业实施DMA将提升供水系统管理水平,减小供水管网漏失、降低供水产销差、增加供水效益。     

MMA基混凝土修补材料的制备与性能

混凝土开裂是混凝土破坏最普遍的形式,如不及时对裂缝修补,将造成混凝土由表及里的破坏,严重影响混凝土的耐久性。因此,采用性能优良的修补材料进行修补,对提高混凝土工程的安全性和延长其使用寿命具有重要意义。甲基丙烯酸甲脂(MMA)基混凝土修补材料是由MMA和引发剂、增塑剂等合成的高分子聚合物,它具有粘度小、凝固体强度高、与混凝土粘结牢固等性能。通过对MMA基混凝土修补材料的合成,详细探讨了引发剂和增塑剂对材料粘度以及材料力学性能的影响。结果表明:引发剂浓度过大或过小,都会使材料的粘度变小,引发剂的适宜质量分数是0.6%～0.7%,增塑剂浓度的增加使粘度增大,修补材料的力学性能达到了修补混凝土的要求,变形性能良好,可以承受一定的荷载变形。     

制氢转化气蒸汽发生器管束内漏故障分析及其处理

转化气蒸汽发生器是制氢装置的关键设备之一。该设备的内漏故障,影响到装置及下游装置的正常运行。详细分析了故障产生的原因,制定了合理的修复方案,特别是焊接工艺中的消氢处理,有效地释放残留在工件上的氢,防止在打磨及焊接过程中产生裂纹。     

Lifetime determination of tetragonal zirconia under static loading using the Constant Stress Rate method

Subcritical crack growth is a phenomenon which limits service time of a ceramic material. It is especially prevalent for oxides, because this phenomenon is attributed to the activity of water at the crack tip of the material and can be caused even by water present as a humidity in the air (Salem and Jenkins, 2002; Michalske and Freiman, 1983). It is very important to determine its lifetime at the setting loads with high probabilities of survival. The Constant Stress Rate method gives results that are sufficient for lifetime predictions. Estimations are based on n parameter which results from the slope of the strength vs. stress rate dependence. Only a conversion from dynamic to static conditions has to be done (Wojteczko et al., 2016). The attempts were made at different stress rates on sintered samples with pre-existing flaws and in two environments − air and water. Tetragonal zirconia was the tested material. Biaxial loading method was used for strength measurements. Microstructural and fractographic observations were made using the scanning electron microscope.     

Use of bacteria to repair cracks in concrete

As synthetic polymers, currently used for concrete repair, may be harmful to the environment, the use of a biological repair technique is investigated in this study. Ureolytic bacteria such as Bacillus sphaericus are able to precipitate CaCO₃ in their micro-environment by conversion of urea into ammonium and carbonate. The bacterial degradation of urea locally increases the pH and promotes the microbial deposition of carbonate as calcium carbonate in a calcium rich environment. These precipitated crystals can thus fill the cracks. The crack healing potential of bacteria and traditional repair techniques are compared in this research by means of water permeability tests, ultrasound transmission measurements and visual examination. Thermogravimetric analysis showed that bacteria were able to precipitate CaCO₃ crystals inside the cracks. It was seen that pure bacteria cultures were not able to bridge the cracks. However, when bacteria were protected in silica gel, cracks were filled completely.     

微生物菌落体系对混凝土裂缝自修复效果的影响综述

开裂是混凝土结构常见的病害,裂缝为外界水和侵蚀性介质提供了通道,侵蚀性介质的进入会导致混凝土耐久性能加速劣化,严重影响工程结构的服役寿命。为有效阻止有害离子的侵入,延长构件服役期限,裂缝的及时修补是目前建筑业所共同面临的问题。微生物自修复混凝土受到了研究学者的广泛关注,与传统混凝土不同,微生物自修复混凝土赋予结构裂缝自诊断、自修复的功能,其主要修复体系可分为两种:一元修复体系和多元修复体系。本文从两种不同修复体系角度分析了微生物自修复混凝土的修复效果,总结了各体系下面临的关键问题,对比了两种体系下自修复效果的优缺点,并展望了基于微生物矿化的混凝土裂缝自修复研究的发展方向。对已有研究成果总结发现,若以一种具有矿化功能的核心菌体为基础,再加入厌氧型细菌辅助矿化,可实现裂缝深度修复,这种新型矿化体系为基于微生物矿化的自修复混凝土的研究提供了新思路。     

A comparison of internal self-repair with resin injection in repair of concrete

A comparison is made between the two modes of repair of internal cracks in concrete: resin injection, which is done manually after cracking, and self-repair in which the adhesive for repair is already present in the matrix at the time the cracking occurs. The purpose of the project was to study the effect of various adhesives used for self-repair on the repair of concrete considering factors such as stress transfer capability, varying crack width, and damping. Different release modes and a similar range of adhesives with varying modulus of elasticity were used in the experiments. The purpose for varying the modulus of elasticity was to investigate the penetration ability of the adhesives. It is known that an adhesive's relative stiffness is directly related to its modulus of elasticity, and consequently, its ability to repair cracks is influenced by this factor. Finally, a comparison was made with studies undertaken by others on resin injection repair regarding stress, strain, and modulus of elasticity. Self-repair adhesives with higher modulus of elasticity (stiffer adhesives) transferred stresses well across the crack width allowing the crack to sustain as much, if not more, as the original loading as measured by specimen strength. The adhesives with lower modulus of elasticity (more flexible adhesives) also transferred the stresses.     

聚合釜人孔开裂成因分析与修复

解剖聚合釜人孔接管 ,对其裂纹进行分析 ,找出了裂纹启裂的原因 ,提出了人孔修复措施     

Deionization shocks in crossflow

Shock electrodialysis is a recently developed electrochemical water treatment method that shows promise for water deionization and ionic separations. Although simple models and scaling laws have been proposed, a predictive theory has not yet emerged to fit experimental data and enable system design. Here, we extend and analyze existing “leaky membrane” models for the canonical case of a steady shock in crossflow, as in recent experimental prototypes. Two-dimensional numerical solutions are compared with analytical boundary-layer approximations and experimental data. The boundary-layer theory accurately reproduces the simulation results for desalination, and both models predict the data collapse of the desalination factor with dimensionless current, scaled to the incoming convective flux of cations. The numerical simulation also predicts the water recovery increase with current. Nevertheless, neither approach can quantitatively fit the transition from normal to over-limiting current, which suggests gaps in our understanding of extreme electrokinetic phenomena in porous media.     

Mechanism for Salt Scaling

Over the past 60 years, concrete infrastructure in cold climates has deteriorated by "salt scaling," which is superficial damage that occurs during freezing in the presence of saline water. It reduces mechanical integrity and necessitates expensive repair or replacement. The phenomenon can be demonstrated by pooling a solution on a block of concrete and subjecting it to freeze/thaw cycles. The most remarkable feature of salt scaling is that the damage is absent if the pool contains pure water, it becomes serious at concentrations of a few weight percent, and then stops at concentrations above about 6 wt%. In spite of a wealth of research, the mechanism responsible for this damage has only recently been identified. In this article, we show that salt scaling is a consequence of the fracture behavior of ice. The stress arises from thermal expansion mismatch between ice and concrete, which puts the ice in tension as the temperature drops. Considering the mechanical and viscoelastic properties of ice, it is shown that this mismatch will not cause pure ice to crack, but moderately concentrated solutions are expected to crack. Cracks in the brine ice penetrate into the substrate, resulting in superficial damage. At high concentrations, the ice does not form a rigid enough structure to result in significant stress, so no damage occurs. The morphology of cracking is predicted by fracture mechanics.     

Visualization of water penetration in cementitious materials with superabsorbent polymers by means of neutron radiography

Concrete cracks due to its low tensile strength. As both harmful gases and fluids may enter the concrete by migrating into cracks, the durability is endangered. The service life decreases, repair costs rise and buildings could structurally decline. In the current research, crack sealing is enhanced by the use of superabsorbent polymers (SAP). When cracking occurs, SAP particles are exposed to the humid environment and swell, sealing the crack. By means of neutron radiography, the moisture distribution is studied during capillary absorption and water permeability tests. Capillary absorption in a crack and water permeability through a crack are reduced in specimens containing SAP particles. SAP particles are able to seal the crack, thus allowing a recovery of the water-tightness of the structure. The total uptake of potentially harmful substances hereby lowers, leading to an enhanced long-term durability and lower maintenance costs.