合成甲醇装置变换炉出口管道开裂失效原因分析

合成甲醇装置变换炉出口管道多处开裂造成泄漏,影响装置正常运行。采用宏观检查、无损检测、化学成分分析、壁垢化学组成分析、金相组织检验、硬度检验以及断口形貌分析等方法对开裂管道进行取样分析,结合工艺装置实际运行情况探讨管道失效原因,认为是工艺波动易形成干-湿交替的管道环境,氯离子在管道湿环境下富集形成酸性介质,敏感材质在酸性介质中受应力作用所致的腐蚀开裂。

Cause Analysis of Crack and Failure of Conversion Furnace Outlet Pipeline of Methanol Synthesis Unit

The outlet pipeline of the conversion furnace of the synthetic methanol plant cracked in many places,caused leakage and affected the normal operation of the unit.The methods of macroscopic inspection,non-destructive testing,chemical composition analysis,wall scale chemical composition analysis,metallographic structure inspection,hardness test and fracture morphology analysis were used to sample and analyze the cracked pipeline.Combined with the actual operation of the process unit,the failure reason of the pipeline was discussed.It was considered that the process fluctuation was prone to form the dry wet alternate pipeline environment,the chloride ion was enriched in the wet environment of the pipeline,and the corrosion and cracking of sensitive materials were caused by stress in acidic media.