斜管沉淀池应用中存在问题的探讨

斜管沉淀池是目前广泛使用的污水物化处理工艺。针对实际应用所遇到的问题，如沉淀池进口布水不均匀，致使出水水质下降，从沉淀的基础理论，通过水力学的分析，较深入地说明了斜管沉淀池矾花泛起，水质恶化的原因。并提出了应用斜管沉淀池应注意的事项。     

DISCHARGE CHARACTERISTICS OF PERFORATED PIPE FOR USE IN INFILTRATION TRENCHES1

ABSTRACT: Infiltration trenches are an effective stormwater management alternative for the control of urban runoff from small areas. Perforated pipes buried within the gravel of an infiltration trench are used to distribute the inflowing runoff along the length of the trench. Laboratory tests are described that characterize the hydraulics of the orifices in perforated pipes. The results show that the steady-state exfiltration of water from the pipe into a surrounding gravel trench can be described by the orifice equation.     

一起氨制冷系统管道断裂事故的原因分析

制冷系统的库房回气管道发生了断裂失效,断裂位置在环焊缝中心且断口平整,焊缝存在未焊透缺陷。管道采用管束整体发泡保温,增加了管道的刚性,不利于管道的位移补偿。通过对管道材质进行分析,化学成分和力学性能符合设计要求。对管道受力状态进行分析并进行应力计算,结果表明,管道焊接接头未焊透,削弱了焊接接头的承载能力。管道在"冷缩"时不能补偿而产生较大的拉应力,导致在管道强度薄弱的焊接接头处发生断裂失效。     

原水水质对输水管道硝化作用形成的影响

采用配制水样模拟Ⅱ类、Ⅲ类和劣Ⅴ类地表水,利用管道模拟反应器研究不同原水水质条件下输水管道中硝化作用的形成及对输水水质的影响.结果表明:原水中氨氮(NH4+-N)及溶解氧(DO)含量对NH4+-N去除均有一定影响,DO充足时,去除率随原水中NH4+-N含量的增加而增加,DO浓度低时,DO成为影响NH4+-N去除的主要因素;原水NH4+-N含量对运行初期NO2--N积累有重要影响,NH4+-N含量越高,NO2--N积累量越大,随着生物膜的成熟,影响作用逐渐减弱;反应器中AOB数量主要受原水NH4+-N浓度的影响,随NH4+-N浓度升高而增加;NOB数量受NH4+-N和DO浓度的双重影响,DO含量低会抑制NOB活性,使NOB数量减少,导致NO2--N积累;输水管道中的硝化作用是水中及生物膜中硝化细菌共同作用的结果,但生物膜中硝化细菌存在水平高,其硝化作用占主导地位.     

塑料管材输配水过程中有机物释放规律研究

研究了目前给水管网中常用的3种塑料管材,未增塑聚氯乙烯(uPVC),聚乙烯(PE)和无规共聚聚丙烯(PPR)管在输配水过程中有机物的释放规律.通过静态管段实验模拟给水管网中不同输配水状态,选取总有机碳(TOC)为综合评价指标,考察了不同塑料管材中有机物随时间的迁移释放特性,并分析了管材有机物释放对管网水中余氯消耗的影响.随着管材输配水次数的增加,uPVC管释放至水中的TOC浓度和TOC释放速率分别在0.03mg/L和0.04μg/(d?cm2)以下,而PE管和PPR管在输配水过程中TOC的释放浓度和释放速率在初期最大[PE: 0.19mg/L,0.25μg/(d?cm2);PPR:0.07mg/L,0.09μg/(d?cm2)],且后期递减并趋于平稳[PE:0.03~0.08mg/L,0.05~0.10μg/(d?cm2);PPR:0.01~0.03mg/L, 0.01~0.04μg/(d?cm2)].随着水力停留时间的增加,不同管材释放的有机物浓度持续升高.不同管材有机物的释放能力排序为:PE>PPR>uPVC.各管材的有机物释放特性直接影响管网水的余氯消耗特性,且管材的有机物释放量越多,管网水的余氯消耗越快.PE管的使用易引起水体有机污染问题.本研究明确了3种常用塑料管材的有机物释放规律,将进一步为与塑料管材安全性能评价相关的国家标准的修订提供理论依据.     

Theoretical and Experimental Investigation of a Novel Hybrid Heat-Pipe Solar Collector

Abstract

This article describes a novel flat plate heat-pipe solar collector, namely, the hybrid heat-pipe solar collector. An analytical model has been developed to calculate the collector efficiency as well as simulate the heat transfer processes occurring in the collector. The effects of heat pipes/absorber, top cover, flue gas channel geometry, and flue gas temperature and flow rate, on the collector efficiency were investigated based on three modes of operation, i.e., solar only operation, solar/exhaust gas combined, and solar, exhaust gas and boiler combined. Experimental testing of the collector was also carried out for each of these modes of operation under real climatic conditions. The results were used to estimate the efficiency of the collector and determine the relation between the efficiency and general external parameter. The modeling and experimental results were compared and a correlation factor was used to modify the theoretical predictions. It was found that the efficiency of the collector was increased by about 20–30% compared to a conventional flat-plate heat pipe solar collector.     

氨制冷系统压力管道安装及实验的要点

近年来,液氨管道事故的不断发生,引起了人们对氨制冷管道系统工程的高度重视.首先介绍了氨的性质,然后介绍了氨制冷管道安装及实验应该注意的一些要点,希望能对氨制冷工程的管道安装质量起到一些作用.     

Assessment of domestic water quality: case study, Beirut, Lebanon

In urban cities, the environmental services are the responsibility of the public sector, where piped water supply is the norm for urban household. Likewise, in Beirut City (capital of Lebanon) official water authorities are the main supplier of domestic water through a network of piping system that leaks in many areas. Beirut City and its suburbs are overpopulated since it is the residence of 1/3 of the Lebanese citizens. Thus, Beirut suffers deficiency in meeting its water demand. Water rationing, as a remedial action, is firmly established since four decades by the Lebanese Water Authorities. Consumers resorted then to private wells to supplement their domestic water needs. Consequently, household water quality is influenced by external factors relating to well water characteristics and internal factors depending on the types of the pipes of the distribution network and cross connections to sewer pipes. These factors could result in chemical and microbial contamination of drinking water. The objective of this study is to investigate domestic water quality variation in Beirut City emerging form the aforementioned factors. The presented work encircles a typical case study of Beirut City (Ras Beirut). Results showed deterioration pattern in domestic water quality. The predicted metal species and scales within the water pipes of distribution network depended on water pH, hardness, sulfate, chloride, and iron. The corrosion of iron pipes mainly depended on Mg hardness.     

油气输送焊管残余应力测试与安全评价方法研究

针对油气输送焊管残余应力测试与评估技术难题,采用机械切割应力释放法对不同成型工艺和状态焊管的残余应力进行了测试分析对比,结果表明:UOE焊管的残余应力分布水平较低;ERW焊管次之;SSAW焊管的残余应力分布范围较广,有高有低。不同管型和成型工艺及水压试验状态具有明显不同的残余应力分布特征,在进行焊管安全评价时必须区别对待。根据残余应力实测结果提出了焊管安全评价时残余应力的取值建议。研究结果对管道设计、安全分析与评价、焊管残余应力的改善、控制及焊管合理选用具有重要工程意义。     

双套管长距离干灰输送系统在330 MW机组上的应用

介绍了国电电力建设研究所的双套管输送干灰技术在国电谏壁发电厂330 MW机组第一电场长距离干输灰中的应用,重点介绍了系统设计、安装、调试和运行,以及系统性能测试情况.