600MW超临界“W”火焰锅炉劣质煤稳燃技术探究

针对600MW超临界W火焰锅炉燃烧劣质煤时存在低负荷燃烧不稳定、锅炉结焦、燃烧效率低、受热面超温、炉渣及飞灰含碳量高等问题，以直流狭缝式燃烧器W火焰锅炉为研究对象，通过改进吹灰方式，调节燃烧器乏气缩孔开度、煤粉细度、磨煤机出口风温、热风温度，并结合二次风配比、燃尽风开度及制粉系统与氧量实时协同优化调整。调整后的运行结果表明：低负荷锅炉燃烧不稳定、水冷壁超温得到解决，热负荷分布更均匀，炉渣及飞灰含碳量明显降低，锅炉效率得到提升。     

600MW机组制粉系统优化调整试验研究

针对湛江中粤能源有限公司600MW机组实际运行存在的一次风速最大偏差大、空气预热器出口两侧温度和氧含量偏差较大、煤粉细度较粗以及磨煤电耗高等问题进行了一次风速调平试验,分离器挡板开度试验以及变加载力、变出力和变通风量试验,根据试验结果对机组运行参数进行了优化调整,改善了磨煤机风煤比均衡性、煤粉细度及电耗,提高了机组运行的经济性和安全性。     

大型火电站低NOx煤粉炉新型燃烧器应用综述

目前我国电站锅炉的NOx排放均明显超标,因此,对电站锅炉进行低NOx煤粉燃烧技术改造是十分必要的。论述了低NOx煤粉燃烧器的原理,分析了5种燃烧器的技术特征,给出了新型燃烧技术在火电站的应用实例。最后指出,低NOx煤粉炉新型燃烧器技术具有低负荷稳燃、防结渣、防高温腐蚀和降低NOx排放的综合效果。     

670MW贫煤锅炉高温受热面热偏差大的原因分析及改进

华电潍坊发电有限公司#3锅炉自2006年投产后存在受热面左、右管壁热偏差大现象，管壁易超温，曾多次出现超温爆管事故。找出了锅炉燃烧热偏差及汽温偏差的原因，制订了合理的改造方案及运行调节措施，通过试验数据论证了改造方案及措施的可行性并成功投入运用。     

850t／h锅炉金属管壁超温分析及运行控制

从锅炉运行实际情况及设备结构上分析了陡河发电厂850t／h炉金属管壁超温的原因，提出了运行操作上应采取的控制措施。指出控制炉膛出口烟温、努力消除炉内热偏差是控制锅炉金属管壁超温的关键。     

增量式函数观测器在W形火焰直流锅炉汽温控制中的应用

针对W形火焰超临界直流锅炉过热蒸汽温度与煤水比控制耦合性强、炉膛温度过高易结焦、过热汽温控制对象迟延时间和惯性时间长等特点,在华电四川珙县电厂2×600 MW机组过热汽温串级PID控制系统中加入增量式函数观测器状态反馈控制。实际调试及应用表明,过热汽温动态特性明显改善,变工况时过热汽温偏差控制在允许范围之内。方案具有较强的实用性,为超临界机组的控制提供了参考和借鉴。     

托电公司“一一·五”事件与锅炉低负荷稳定燃烧

介绍了低负荷时锅炉稳定运行的机制,论述了煤粉着火原理及运行措施。在突发事故时可减少燃油使用,达到安全、稳定运行的目的。     

600MW超临界机组燃烧调整中SOFA摆角的作用

通过锅炉燃烧调整试验,标定了二次风量、O2含量和排烟温度,进行了SOFA摆角调整对汽温偏差影响的试验,给出了SOFA风水平摆角优化运行的推荐参数。     

超临界直流锅炉冷态空气动力场研究

针对四角切圆锅炉水平烟道上普遍存在烟温偏差的情况,在河北国华定洲发电厂新建锅炉开展了冷态空气动力场试验,重点研究炉膛出口烟气流速分布情况。试验证明,通过调整分离燃尽风（SOFA）喷嘴的角度,能有效改变炉膛出口气流的分布,保证左、右烟气流速均匀,可满足锅炉正常运行的要求。     

300MW机组低氮燃烧器改造及对再热汽温的影响分析

介绍了300 MW机组锅炉低氮燃烧器改造情况,改造后锅炉NOx排放值从改造前的1 000 mg/m^3左右降低到400 mg/m^3左右,降低氮氧化物幅度在60%以上,减轻了脱硝装置的压力,达到了优化设计、优化运行的目的,并对低氮燃烧器改造后锅炉再热汽温偏低的情况进行了分析和研究。     

地下厂房施工过程的三维非线性数值模拟分析

根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。     

Evaluation of freshwater mussel relocation as a conservation and management strategy

The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects.     

基于模型试验的河床砂砾石层基本特性研究

为了经济可靠地确定深厚覆盖层的基本特性参数,以大渡河双江口水电站坝基河床砂砾石层基本特性研究为工程背景,进行大尺寸模型试验,研究河床砂砾石层的旁压模量和动探击数随密度、级配以及上覆压力的变化规律。根据室内模型试验结果,结合现场旁压试验及钻孔试验成果,推断出坝址区河床砂砾石相关层位的密度,并依此进行砂砾石室内力学试验,获得设计所需力学参数。研究成果可为深厚覆盖层基本特性测试提供新的方法。     

基于BP神经网络-马尔科夫链模型的隧道围岩位移预测

在隧道工程施工中,围岩位移预测起着很重要的作用。将BP神经网络-马尔科夫链模型引入到隧道围岩位移预测中来,通过对训练样本的学习,利用BP神经网络实现了对位移时间序列的滚动预测,同时得到了实测值与预测值的相对误差;在此基础上利用马尔科夫链对相对误差进行修正,有效地提高了预测结果的精度。并将该模型应用于某公路隧道拱顶下沉位移时序预测中,结果表明该模型具有精度高、科学可靠的特点,为隧道围岩变形的预测提供了新的途径。     

Short communication. Pipelines as a refuge for freshwater snails

In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment.     

浙江省水域调查录入系统的设计和应用

浙江省水域调查录入系统将调查数据与电子地图相整合,对分类水域数据进行统计计算,并对输入数据进行合理性和完整性检查,得到调查范围内现有水域的详细数据,实现了水域调查数据输入、计算、统计和查询的数字化管理,提高了工作效率和工作质量,为各地下阶段水域保护规划编制和水域管理工作提供了数据支持。对该系统的设计原则、功能和技术设计等作了介绍。     

基于CT-连续加荷水泥乳化沥青混凝土细观损伤规律研究

利用CT技术对水泥乳化沥青混凝土的细观损伤过程进行实时扫描观测,获得了混凝土试件在连续加荷下的CT图像。通过采用直观分析法、CT数分析法、CT数与损伤变量关系3种方法分析表明,水泥乳化沥青混凝土的破坏过程可分为压密、扩容、裂纹扩展、破坏4个阶段,同时混凝土在受压过程中具有韧性,在极限荷载之前各断面处于压密和微扩容的强化阶段,极限荷载之后混凝土从损伤到破坏发展比较平稳。     

Automated system for removal and pneumatic transport of fly ash from electric precipitator hoppers

A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system, configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants of dry ash utilization and the advantages of producing of size-separated particles are considered. __________ Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008).     

The flood pulse advantage and the restoration of river-floodplain systems

The ‘flood pulse advantage’ is the amount by which fish yield per unit mean water area is increased by a natural, predictable flood pulse. Evidence for this increase is presented from tropical and temperate fisheries. It is argued that increasing multispecies fish yield by restoring the natural hydrological regime is consistent with increasing production of other trophic levels and with restoration from ecological and aesthetic viewpoints. When applied to a river-floodplain system, this restoration would provide a large, self-sustaining potential for recreation, commercial exploitation, and flood control. An interim ‘natural flood pulse’ restoration approach is proposed for systems modified for navigation. This approach approximates the natural hydrological regime in a river reach and is intended as a first step in the long process of restoring the watershed.     

浅谈天湖水电站水轮机运行故障及处理措施

简述天湖水电站投运以来各种故障的表现形式，分析其原因，提出了相应的处理方法及措施，并对合理利用国内外设备提出建议。