俄供机组低温再热器腐蚀分析  

Analysis on corrosion of low temperature reheater in a Russian-made power plant

作　　者：张广文 胡杨[2] 刘锋[2] 王德军[3] 张翠伶 王凤仙[2] 刘永兵[2] 

机构地区：[1]神华国华(北京)电力研究院有限公司,北京100025 [2]西安热工研究院有限公司,陕西西安710032 [3]神华国华绥中发电有限责任公司,辽宁葫芦岛125200 [4]神华国华盘山发电有限责任公司,天津301900

出　　处：《热力发电》2017年第2期120-124,共5页Thermal Power Generation

摘　　要：针对国内俄供机组停备用期间各受热面均发生不同程度腐蚀,其中低温再热器入口段弯头部位腐蚀最为严重的问题,对某俄供机组低温再热器入口管的腐蚀情况进行了考察,并采用光学显微镜、扫描电镜、电子衍射能谱仪、X射线衍射分析仪等对腐蚀发生的位置、腐蚀产物的组成、形貌、成分进行了分析。结果表明,低温再热器入口管腐蚀的原因为机组停用过程中的溶解氧腐蚀。由于管段材质、位置结构、设计与实际安装使用存在差异,不当的停机过程中低温再热器入口管内会积存浓缩后的凝结水,其中腐蚀性阴离子Cl-、SO42-浓缩后会促进腐蚀的发展,空气中的氧促进了金属腐蚀的发生。因此,俄制机组在停机过程中,应避免低温再热器管路中凝结水的产生,考虑加入必要的停炉保护剂。The heating surface of Russian-made power plants suffers various corrosion during the downtime and standby period,especially at the bending area of low temperature reheater inlet. Thus,this paper inspects the corrosion condition of the inlet pipes of low temperature reheater in a Russian-made unit, and optical microscope,electron diffraction spectrometer and X-ray diffraction analyzer were used to analyze the corrosion location, composition and morphology of the corrosion products. The results indicate that, the dissolved oxygen corrosion occurred during the laying up of the plant is the major reason for inlet pipes corrosion of tow temperature reheater. Because the pipe materials,iocation structure and design are inaccordance with the actual installation,some condensation water will deposit in the inlet pipes of low temperature reheater during the unsuitable shutdown process. The corrosive ion Cl^- and SO4^2- in the condensed water can promote the development of corrosion and the dissolved oxygen can induce the corrosion of pipes after the air leaked into the system. Therefore, during the shutdown process of the Russian-made unit, the production of condensed water in the low temperature reheater should be avoided, and necessary boiler stopshut down protective agent should be considered.

关 键 词：俄供机组 低温再热器 停用腐蚀 溶解氧 凝结水 腐蚀电池 氧化皮 

分 类 号：TK224.9[动力工程及工程热物理—动力机械及工程]