摘要
某电厂水冷壁管连续发生爆漏造成锅炉故障停机,通过宏观观察、化学元素分析、金相分析、力学性能分析、扫描电子显微镜和能谱分析等方法对爆漏水冷壁管屏进行了综合性失效分析。结果表明,给水中含氧量超标,导致水冷壁积垢严重,凝汽器发生泄漏污染了给水,在内壁结垢处发生局部浓缩,形成酸性环境,进而发生垢下腐蚀;腐蚀产生的氢气分子与钢中的渗碳体和游离碳发生化学反应生成甲烷气体,造成钢材脱碳;甲烷气体分子不能溶入钢中,致使沿晶界形成大量微裂纹,从而引发水冷壁大面积氢腐蚀损伤。针对该问题,提出严格控制水质、减少结垢并根据结垢情况及时安排酸洗清理垢样等措施。
The consecutive accidents of water wall tube explosion occurred in a power plant,which seriously affected the safe and stable operation of the plant.In order to avoid the recurrence of such accidents,a comprehensive failure analysis of the water wall tube panel is carried out through macroscopic observation,chemical element analysis,metallographic analysis,mechanical property analysis,scanning electron microscope and energy spectrum analysis.The results show that the oxygen content in the feed water exceeds the standard,which leads to serious scaling on the water wall,and leakage of the condenser pollutes the water supply.The scaling on the inner wall is locally concentrated,resulting in an acid environment and forms corrosion under scale.The hydrogen molecules produced by corrosion react with the cementite and free carbon in the steel form methane gas,resulting in decarburization of steel,and the methane gas molecules cannot be dissolved.A large number of microcracks are formed along the grain boundary,which resulted in large area hydrogen corrosion damage of water wall.It is suggested that the water quality should be strictly controlled to reduce scaling,and acid cleaning should be arranged in time according to the scaling situation.
作者
谭晓蒙
张涛
乔欣
陈浩
田峰
TAN Xiaomeng;ZHANG Tao;QIAO Xin;CHEN Hao;TIAN Feng(Inner Mongolia Power Research Institute,Hohhot 010020,China)
出处
《内蒙古电力技术》
2020年第5期68-71,共4页
Inner Mongolia Electric Power
关键词
电站锅炉
水冷壁
氢腐蚀损伤
微裂纹
脱碳
power plant boiler
water wall
hydrogen corrosion damage
microcrack
decarburization
