Cause Analysis and Treatment of Internal Corrosion and Leakage of Boiler Water Wall Tubes
摘 要
对某锅炉水冷壁管内壁腐蚀原因进行分析。根据对水冷壁内壁腐蚀产物进行化学元素分析、金相检测、SEM扫描电镜及EDS能谱分析和XRD衍射分析结果,认为腐蚀原因是凝汽器铜管发生腐蚀泄漏,使炉水质量变差。Cu2+在水冷壁内壁表面上沉积,对水冷壁管内壁保护膜产生破坏作用,导致水冷壁管内壁出现点蚀。而炉水处理过程中磷酸盐的加入,促进了Cu等金属元素在内壁的沉积,加剧了腐蚀的进行。水冷壁内壁的腐蚀产物不断生成并附着在内壁上,既造成管壁持续减薄,又影响了管子的传热效果,使管子在运行中一直处于超温状态,组织逐渐老化。管壁的减薄和材质的老化共同导致该管子无法承受内部介质压力而发生泄漏。为防止同类事故再次出现,制定了具体的处理措施。
Abstract
The causes of severe corrosion of internal corrosion and leakage of the water wall tubes in a boiler were analyzed. Corrosion products on the inner surface of water wall tubes were studied by chemical element analysis, metallographic examination, SEM, EDS and XRD, the results showed that the main reason was the condenser copper tube corrosion, leading to the condensation abnormality. Cu2+ deposited on the inner wall of the water wall surface had a damaging effect on the tube protective film. As the runtime went on, pitting corrosion occurred. Phosphate promoted the deposition of metallic elements such as Cu on the tube inner surface and accelerated the corrosion. Corrosion products generated continuously and attached on the inner wall, made the tube thinning and affected the heat transfer effect. The tube was in a state of overheat in the runtime, the microstructure gradually aged. The tube wall thinning and material aging together leaded to the leakage of the tubes due to the action of the internal medium pressure. To prevent similar accident, some concrete treatment measures were suggested.
中图分类号 TG174
所属栏目 失效分析
基金项目
收稿日期 2013/7/15
修改稿日期
网络出版日期
作者单位点击查看
联系人作者刘爽(gigihou@sina.com)
备注刘爽(1982-),工程师,硕士,从事电力设备腐蚀与防护研究,
引用该论文: LIU Shuang,HU Xin-fang,LIU Rui. Cause Analysis and Treatment of Internal Corrosion and Leakage of Boiler Water Wall Tubes[J]. Corrosion & Protection, 2014, 35(5): 528
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参考文献
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