冷凝器列管腐蚀失效分析

 运用金相显微镜、X—射线衍射、扫描电镜和俄歇电子能谱分析仪对冷凝器列管腐蚀部位的腐蚀形貌、腐蚀产物进行分析，同时结合冷凝器列管的服役环境介质，所处应力状态和制做结构特点的分析，认为由于板管处的间隙造成氯离子的浓缩从而使冷凝器列管发生缝隙腐蚀，在应力作用下，裂纹从管外侧向内侧扩展造成泄漏，使材料发生应力腐蚀破裂。      

MIZ-27SI型涡流检测系统在尿素高压换热器检测中的应用

在大型合成氨的尿素生产装置中 ,常用于尿素2 0 1 ｃ ,2 0 2 ｃ ,2 0 3 ｃ三台高压设备的列管材料为奥氏体不锈钢 ,而管板基层和折流板材料为普通低合金碳素钢。在设备的运行过程中 ,由于尿素介质的腐蚀性和高温高压的特点 ,列管常出现的缺陷有管壁的腐蚀均匀减薄、由氯离子引起的应力腐蚀裂纹、制造缺陷引起的腐蚀、折流板处由滞留物引起的微电池腐蚀以及尿素介质对管子所造成的孔蚀等。为了保证尿素装置的长周期运行 ,就必须对其进行检测。涡流检测具有快速、高效的特点 ,是最适于大量非磁性列管的检测方法。涡流检测以电磁感应原理为基…     

水冷器的焊接修复

我厂引进的某装置内的水冷器,因使用多年,严重腐蚀,造成大量漏水现象,使其失去使用功能,需要更新列管。然而其列管原是胀接的,国内又没有生产此类配件的厂家。为此采取了以手弧焊修复的方法。此管板结构的最大特点是列管管壁与管板     

双相不锈钢2205换热器的焊接

气提塔顶换热器是中油吉化炼油装置中的一项重要设备,它关系到整个系统的生产效率.以往由于换热器壳体采用普通容器钢20R钢、16Mn管板 20钢的列管制造,耐应力腐蚀和抗点蚀的性能较差,经常出现腐蚀泄漏,严重影响生产正常进行.将换热器的管板和换热管改用双相不锈钢2205钢制造,有效改善了腐蚀泄漏现象,使该装置能保证常年正常运行.     

氯化铵外冷器腐蚀分析及防腐蚀涂层保护

联碱生产中氯化铵直外冷器列管腐蚀最为严重，腐蚀主要集中于管端，腐蚀形式有：点蚀，缝隙腐蚀，湍流腐蚀和空泡腐蚀等；介绍了用环氧－酚醛复合涂层对其进行保护的方法。     

油浆换热器管板开裂原因分析

锦州石化六厂的油浆换热器在投入使用半年多就出现管板封头处有多处裂纹，导致不能正常生产。通过油浆换热器管板材料材质的化学成分分析、力学性能测试和金相组织观察，管板断口的宏观分析和微观分析，以及断口的腐蚀产物分析等，得出结论：造成管板开裂的主要原因是硫化氢和水蒸气引起的应力腐蚀破裂。     

核电站蒸汽发生器传热管的点腐蚀及其防护

点腐蚀是一种在蒸汽发生器传热管上产生的微小直径穿孔性管壁腐蚀点,其原因是在该处形成了局部腐蚀电池.它的危害性不仅由于点腐蚀本身会造成穿孔性降质,更重要的是点腐蚀是应力腐蚀等局部腐蚀的先导,会引起核电站的强迫停堆.防止点腐蚀的措施包括:选择传热管材料、控制二次侧水化学杂质、对管板上泥渣堆和管子进行清洗、对传热管进行无损检测等.     

固定管板换热器管板泄露失效分析

固定管板式换热器在运行过程中发生了角焊缝处泄露造成失效,利用光学显微镜、扫描电镜、X衍射以及化学分析等方法对换热管、管板以及焊缝区进行化学成分、显微组织、腐蚀形貌、腐蚀产物进行了分析。结果表明:换热管以及管板等化学成分符合标准要求,母材及热影响区为铁素体+珠光体,焊缝不同区域出现了马氏体以及贝氏体,裂纹周围管板侧和焊缝区的组织差别较大,焊缝区的应力集中以及壳程介质进入缝隙并在操作工艺条件下浓缩,形成高风险碱应力腐蚀敏感性,最终导致在马氏体或贝氏体含量较高的区域开始萌生裂纹并导致了自焊缝底部开裂向焊缝中心发展的裂纹,进而导致换热器角焊缝泄露。     

热钾碱脱碳液中304不锈钢换热器管束的腐蚀失效分析

热钾碱脱碳液304不锈钢管束再沸器投用2年后发生了腐蚀泄漏，检查发现腐蚀发生在管子与管板之间的缝隙中.用电化学方法和能谱分析技术，对304不锈钢换热管及16 Mn管板在热钾碱脱碳液中的极化行为及管子表面腐蚀区的腐蚀产物进行了分析，结果表明：换热器管束的腐蚀是由于缝隙内外五价钒浓差造成的16 Mn管板的活化—钝化短路电池所引起，缝隙内闭塞电池的形成加速了缝隙内16 Mn的溶解速度，并使缝隙内介质酸化及Cl-等阴离子富集，导致304不锈钢管子的腐蚀.      

CPR1000机组蒸汽发生器二次侧检查技术的发展及应用

介绍了国内CPR1000机组蒸汽发生器二次侧管板泥渣冲洗及视频检查技术的发展及应用现状,阐述了目前蒸汽发生器二次侧管板泥渣冲洗及结果评价所采用的技术手段,包括外来物的取出与验收标准。现有设备及技术可满足国内新投运CPR1000机组蒸汽发生器二次侧管板的清洁度检查要求。通过介绍现有设备及技术在应用方面的局限性,旨在为CPR1000机组蒸汽发生器二次侧泥渣冲洗及视频检查技术与设备的进一步研究与开发提供启示。     

Failure analysis of liquefied chlorine condenser

There was a serious blast of liquefied chlorine condenser last year in southwestern China and a few people were killed during the blast. To look for the reason of the explosion, the failed condenser was sampled and investigated through Industrial Computed Tomography (ICT), Scanning Electron Microscopy (SEM) and electrochemical methods. The tube sheet was made of 16MnR, and the tube was made of 10^# seamless steel, while the welding material was J507 welding rod. ICT results showed corrosion in the inner of the tube sheet. Based on the SEM results, it was shown that there was obvious erosion near the inlet of chlorine gas and corrosion at the joint area of tube sheet, tube and welding material was much more serious than that of the other parts. Moreover, the electrochemical tests indicated that the corrosion potential of the tube sheet in 6wt.% FeCl₃ solution was a little more negative than that of the other two parts while in 29.9wt.% CaCl₂ solution the potential of the welding material was more negative than that of the tube. It could be inferred that there existed electrochemical corrosion. At the beginning, local corrosion of tube sheet, tube and welding material of condenser as well as the erosion of the tube interior surface took place. Then the corrosion was speeded up and led to the final failure of the condenser in a very short period after the condenser contacted the mixture of chlorine gas and the CaCl₂ solution contained ammonia, which reacted with chlorine gas to form the explosive NCl₃.     

Corrosion of Condenser Tubes Due to Carbonaceous Film on the Surface

Abstract

This paper describes pitting corrosion that has occurred in the condenser tubes in a numbu of power stations in the Republic of South Africa. The power stations concerned are situated inland and use fresh surface water, concentrated in cooling towers, for condenser cooling. Investigations indicate that the corrosion is similar to the pitting of copper potable water tubes caused in the U.K. and elsewhere by the presence of carbon film formed on the surface during tube manufacture. Many turbine and condenser tube manufacturers, however, disagree with these findings and some of their views are given in this paper. The author is of the opinion that accelerated corrosion due to this cause is more general than most corrosion engineers believe.     

黄铜管开裂失效分析

采用扫描电和Ｘ－射线衍射等技术对黄铜管断口形貌和腐蚀产物等进行了较全面的分析。结果表明，黄铜管的开裂为氯离子引起的穿晶应力腐蚀开裂；为氯离子引起黄铜应力腐蚀开裂提供了实例。     

Using an eddy-current technique for studying local corrosion and scale formation on the walls of heat-exchanger tubes

The results of industrial application of a matrix eddy-current probe in studying local corrosion in heat-exchanger tubes are considered. Local corrosion of several heat exchangers that were used under various conditions has been analyzed by eddy-current techniques. Statistical analysis has confirmed the effect of polymer coatings on local corrosion suppression and prevention. Using an original eddy-current probe, the rate of scale formation on the tubes of a thermal power station condenser has been measured for heat-exchanger tubes that were protected from inside by a polymer coating.     

管材缺陷与微生物对凝汽器不锈钢管的协同腐蚀作用

结合某发电厂凝汽器不锈钢管水侧腐蚀部位分布规律和腐蚀形貌特征,分别对腐蚀部位沉积物、内壁蚀孔附近管材进行化学成分、电镜和能谱分析,探讨了管材缺陷与微生物对凝汽器不锈钢管腐蚀的影响。结果表明,两者在点蚀形成过程中具有协同作用。提出了不锈钢凝汽器在运行过程中应采取的防护措施。     

徐州发电厂凝汽器的腐蚀与防护

凝汽器的腐蚀泄漏严重影响机组的水汽品质，威胁机组的安全经济运行，徐州发电厂通过及时检查和涡流探伤掌握铜管腐蚀情况。采用加强循环冷却水的加药管理，保持铜管清洁，管板刷漆联合阴极保护，FeSO4镀膜等防护措施，在凝汽器腐蚀治理方面取得一定的效果。     

核电站凝汽器管板的腐蚀分析及外加电流阴极保护

大亚湾核电站凝汽器管板存在腐蚀状况,其机理是钛管和铜合金管板在海水中形成电偶腐蚀,采用外加电流阴极保护方法能有效地抑制腐蚀。结果表明,凝汽器增加阴极保护后,保护效果良好,显著提高凝汽器设备的可靠性和机组的安全性。     

海水凝汽器传热管的选材与防护

对海水凝汽器传热管材料与防护各方面问题作了评述，回顾了材质的变迁历程，重点对铜合金管与钛管的腐蚀或损伤，从可靠性与经济性方面作了比较分析。     

交流阻抗法在凝汽器黄铜管腐蚀研究中的应用

探讨交流阻抗法研究凝汽器黄铜管在循环冷却水系统中的腐蚀问题.采用热电厂实际使用的黄铜管制作管状传感器,利用交流阻抗法在同种材料三电极体系电解池中测量传感器的电化学阻抗谱,并与经典三电极体系电解池下的数值作比较.结果表明,实验室数据与现场测试数据基本吻合,交流阻抗法可以提供凝汽器黄铜管在循环冷却水系统中的年腐蚀速率和极化电阻,帮助现场工作人员及时了解凝汽器黄铜管的腐蚀状况.交流阻抗法可以有效地评定黄铜管的耐腐蚀性能,为现场腐蚀监测,进而指导生产提供了有益信息.     

海水泄漏对SG二次侧金属腐蚀的实验分析

通过给水中掺入一定比例的厂区海水,采用静态高压釜真实模拟凝汽器海水泄漏后的SG二次侧水质,研究了不同海水污染程度下SG二次侧内部构件金属材料的均匀腐蚀、点蚀和应力腐蚀性能.海水泄漏加剧了SG内碳钢和低碳钢部件的腐蚀,抑制了马氏体、奥氏体不锈钢钝化膜的生长,加剧了镍基合金表面氧化物的沉积,为核电厂治理凝汽器海水泄漏事件的...