电站锅炉水冷壁爆管故障树分析

系统分析了引起电站锅炉水冷壁管爆管的因素,建立了以电站锅炉水冷壁管爆管为顶事件的故障树,并通过故障树分析得到各阶最小割集.采用近似计算方法,计算出基本事件的结构重要系数,确定影响电站锅炉水冷壁爆管的主要因素.为提高电站锅炉水冷壁的安全性和运行可靠性,提出了相应的预防措施.     

某410t/h锅炉水冷壁爆管的分析及对策

燃煤锅炉水冷壁爆管严重影响锅炉的运行,严重的爆管直接导致锅炉灭火.本文通过对某锅炉的运行分析,了解了水冷壁爆管的主要和次要因素,并提出一些可以解决的办法.     

一例热水锅炉水冷壁爆管的修理及预防

2006年冬季,开滦集团内的一台锅炉由于水质不达标,造成水冷壁爆管,严重影响生产.结合此例,介绍了锅炉水冷壁爆管修理方案及修理过程,提出整改的措施,整改修理后,系统运行将近两年,水质稳定,锅炉运行正常安全.     

某循环流化床锅炉水冷壁管水垢堵塞爆裂的案例分析

针对一起锅炉水冷壁爆管事故,从水冷壁的受热状态、水动力循环、水汽质量以及锅炉运行等方面进行了分析,指出了该部位水冷壁爆管的原因,并提出相应的解决和预防措施。     

燃气电站锅炉水冷壁爆管失效原因分析

某燃气电站锅炉在50 MW机组在48 h内连续3次发生水冷壁爆管失效。对水冷壁爆口的宏观形貌进行了分析,采用光学显微镜对爆口及附近区域进行了金相分析,利用布氏硬度计对爆口表面及断面进行了硬度分析,用光谱仪进行了成分分析。结合锅炉运行状况及近期水质状况分析表明水冷壁结垢和锅炉负荷波动过大是造成水冷壁爆管的主要原因,水冷壁管材质存在一定的劣化现象,造成水冷壁管高温强度降低是造成水冷壁爆管的次要原因。     

一起水冷壁管爆管事故分析

某厂一台KZW2—13—AⅡ斜推往复炉排锅炉,在1987年5月9日上午出现锅炉左侧炉墙有大面积渗水,当即停炉。拆开左侧炉墙,发现一根水冷壁管爆管,水自爆管处流出。该锅炉在1986年5月29日也出现了一次左侧水冷壁管爆管,两次爆管间隔时间仅一年。事故发生第二天上午,我们对该锅炉进行了全面检查:锅炉右侧水冷壁管无严重腐蚀现象,紧靠水冷壁管的耐火材料为白色质干。左侧水冷壁管大面积腐蚀,紧靠水冷壁管的耐火     

新型DZ蒸汽锅炉水冷壁爆管分析与对策

2006年部队某单位安装1台新型DZL4—1．25-AⅡ蒸汽锅炉，当年使用，锅炉采用锅外钠离子交换水处理，锅炉主要用于宾馆洗浴和食品加工。2008年9月19日，锅炉运行中，发生水冷壁管爆管事故，大量汽水喷入炉膛，使锅炉无法正常运行而紧急停炉。经检查发现锅炉左侧第3#水冷壁管爆管泄漏，停炉进行割管、管端封堵修理后，锅炉继续运行，运行不到1个月时间，相继锅炉左侧4=#～7#水冷壁管又发生爆管泄漏。停炉后经我所检验发现，爆管左右相邻4根水冷壁管均有不同程度胀粗现象。为查明锅炉事故原因，做出相应防范措施，对爆管水冷壁管及相邻水管进行割管检验。     

超(超)临界压力锅炉垂直管屏水冷壁水动力与热偏差调整建议

垂直管圈超(超)临界压力锅炉一般都在水冷壁管入口安装节流圈,以调节工质流量,使其与对应区域的热负荷相匹配,但是该类型锅炉在投运后往往出现水冷壁节流圈结垢、水动力和热偏差,以致发生爆管.通过对水冷壁结构特点的分析,对爆管原因进行了研究,参考亚临界垂直管圈直流锅炉水动力调整经验,提出超(超)临界压力锅炉垂直管屏水冷壁系统改进和进行水动力调整的建议,即减少水冷壁管入口节流圈数量,在水冷壁管(屏)的入口安装调节装置以及加装水冷壁管屏的监视测点等.     

电站锅炉炉膛爆炸事故原因及预防

电站锅炉炉膛爆炸是火力发电厂事故中比较严重的事故之一.论述了电站锅炉因煤粉等燃料的爆燃、水冷壁爆管、过热器爆管、再热器爆管、炉底析铁氢爆等导致炉膛破坏的原因,并针对不同的爆炸原因,分别提出了相应的预防炉膛爆炸措施.     

某600 MW亚临界机组锅炉水冷壁爆管原因分析

对某亚临界600 MW燃煤发电机组水冷壁爆管管样进行了爆口宏观检查、垢层形貌、垢量、种类成分及金相组织检验,认为爆管是由于水冷壁向火侧内表面发生了严重的酸性腐蚀和氢损伤所致.垢下酸性腐蚀导致水冷壁有效壁厚减薄以及氢损伤造成金属基体强度下降是造成水冷壁爆管的根本原因,建议对该锅炉进行化学清洗,加强日常化学监督工作,对易发...     

350MW锅炉末级过热器频繁爆管的处理

350MW锅炉末级过热器频繁爆管,对末过及集箱进行内窥检查和取样检验,并对炉内相应管屏安装测点,采集壁温数据,分析造成爆管的原因,针对带5%BMCR过热器小旁路的机组采用少油点火启动方式进行燃烧调整,解决爆管问题使机组稳定运行。     

300MW循环流化床锅炉受热面爆管的事故处理

简要介绍300MW循环流化床锅炉受热面布置情况、受热面爆管的现象和处理情况以及预防措施。     

丰源4#锅炉过热器爆管的分析

通过对过热器爆管的分析,论述了循环流化床锅炉在短时间压火后重新启炉时存在的后燃隐患,直接影响了过热器的使用寿命,甚至发生爆管;并提出了操作方面应采取的相应措施。     

CFD investigation on the effect of air temperature on air blowing cooling system for preventing tube rupture

In this study a solution for preventing tube rupture in the superheater region of the 320 MW Bisotoun power plant boiler, Iran, was suggested. Based on our previous study, the air blowing system which locally cools the tube in place of tube rupture was proposed. Due to huge differences in air temperature at different seasons in the region the air with different inlet temperatures was blown over the modeled tube. The CFD results showed that the inlet air temperature has no significant effect on cooling performance due to high rate of heat transfer to the air carrier tube.     

Numerical study on spontaneous ignition of pressurized hydrogen release through a length of tube

The issue of spontaneous ignition of highly pressurized hydrogen release is of important safety concern, e.g. in the assessment of risk and design of safety measures. This paper reports on recent numerical investigation of this phenomenon through releases via a length of tube. This mimics a potential accidental scenario involving release through instrument line. The implicit large eddy simulation (ILES) approach was used with the 5th-order weighted essentially non-oscillatory (WENO) scheme. A mixture-averaged multi-component approach was used for accurate calculation of molecular transport. The thin flame was resolved with fine grid resolution and the autoignition and combustion chemistry were accounted for using a 21-step kinetic scheme.The numerical study revealed that the finite rupture process of the initial pressure boundary plays an important role in the spontaneous ignition. The rupture process induces significant turbulent mixing at the contact region via shock reflections and interactions. The predicted leading shock velocity inside the tube increases during the early stages of the release and then stabilizes at a nearly constant value which is higher than that predicted by one-dimensional analysis. The air behind the leading shock is shock-heated and mixes with the released hydrogen in the contact region. Ignition is firstly initiated inside the tube and then a partially premixed flame is developed. Significant amount of shock-heated air and well developed partially premixed flames are two major factors providing potential energy to overcome the strong under-expansion and flow divergence following spouting from the tube.Parametric studies were also conducted to investigate the effect of rupture time, release pressure, tube length and diameter on the likelihood of spontaneous ignition. It was found that a slower rupture time and a lower release pressure will lead to increases in ignition delay time and hence reduces the likelihood of spontaneous ignition. If the tube length is smaller than a certain value, even though ignition could take place inside the tube, the flame is unlikely to be sufficiently strong to overcome under-expansion and flow divergence after spouting from the tube and hence is likely to be quenched.     

某锅炉过热器爆管原因分析

分析了过热器由于超温产生爆管的原因和引起管壁超温的几方面因素,并提出了解决超温的设想。     

Self-ignited flame behavior of high-pressure hydrogen release by rupture disk through a long tube

Accelerated adoption of hydrogen gas for energy storage requires improved safety for hydrogen storage. In particular, control of self-ignition of hydrogen vented through tubes by pressure relief devices (overpressure protection devices), such as rupture disks, is needed. We clarify the process of self-ignition in tubes of various lengths during venting of high-pressure hydrogen and observe flame behavior at the tube exit. The importance of distance from the rupture disk for flame front evolution is revealed. Specifically, in a tube longer than a critical value, the self-ignited flame undergoes a quenching process, possibly due to steam formation, before it exits the tube. A tube that is too short does not give the gas sufficient time for hydrogen and air mixing to initiate self-ignition. Finally, at slightly longer tube lengths, the hydrogen ignites, but the flame does not fully develop before it exits, and the vortex formed by expanding gas extinguishes it.     

一台DZL6.0-1.25蒸汽锅炉水冷壁管爆管事故的分析与改进

从对一台ＤＺＬ６．０－１.２５蒸汽锅炉近前炉门附近两侧炉膛水冷壁管多次发生局部爆管事故的调查出发,对该锅炉侧集箱排污系统存在的设计缺陷进行了流动分析、计算。计算表明,排污时前段集箱内流速过低是造成该段集箱区水渣大量沉积致使该区水冷壁管因水渣堵塞而引发局部爆管的根本原因。对侧集箱不同部位增开排污口方案进行的计算表明,在集箱前端增开排污口可有效地改善排污时该处集箱内水的流动性,从而消除泥渣沉积隐患。改造方案实施后,经多年的锅炉安全运行实践也证明了该方案的有效性。     

自备电厂次中压发电锅炉水处理问题探讨

自备电厂次中压发电锅炉过热器经常发生爆管事故，其主要原因常与锅水水质不良，导致过热器内壁积附盐垢后产生局部蠕变变形，最终促使管壁爆破有关。本文结合上述原因的分析，对自备电厂次中压发电锅炉水处理问题提出了具体看法。     

后拱水冷壁高温蠕变爆管事故

本文是对一起后拱水冷壁管高温蠕变爆管事故的技术分析。通过对事故现场进行调查,事故原因是由于后拱耐火砖脱落导致后拱水冷壁受高温产生蠕变爆管。对蠕变、鼓包、爆管管壁的金相组织进行了分析。阐述了蠕变爆管和珠光体球化、石墨化的机理。