材料期刊网

对一段发生泄漏的天然气长输管道进行失效分析.在排除机械损伤和外部因素基础上,通过防腐层实验、化学成分分析、金相组织观察、天然气组分检测、腐蚀产物XRD谱,分析了管道内腐蚀穿孔形成的原因.结果表明,管道内腐蚀穿孔是由氧腐蚀、CO2腐蚀、硫酸盐还原菌腐蚀共同造成的.管道敷设后与投产前内部的空气、投产后天然气中的CO2、管道中的水和泥土在管道腐蚀中起到了关键作用.提出了需要采取开挖检测、更换腐蚀管段、外加电流法阴极保护、进行管道清管与内检测、选择缓蚀剂等措施.

The causes of leakage invalidation of a long-distance natural gas pipeline was analyzed.After excluding the mechanical damage and external factors,much emphasis was placed on the research on how corrosion and perforation could occur inside the pipeline.Various measures were taken to analyze the cause of corrosion and perforation,such as corrosion examination of coatings,chemical com ponents analysis and microstructure observation of the pipe steel,detection of natural gas components and XRD analysis of corrosion products.The result showed that the occurrence of corrosion and perfora tion inside the pipeline was due to the synergistic action of oxygen corrosion,carbon dioxide corrosion and sulfate reducing bacteria corrosion.The air gathered inside after the pipeline was laid underground,carbon dioxide contained in natural gas during operation,water and dirt inside the pipeline,these played a critical role in the pipeline corrosion.To avoid further corrosion,several effective methods must be ad opted,for instance,excavation and detection,replacing corroded pipe,impressed current method,pigging operation as well as internal inspection,using corrosion inhibitor,etc.