海上某平台增压泵出口管线短节腐蚀失效原因分析

Cause Analysis of Corrosion Failure of Outlet Pipeline Joint at Offshore Platform

通过形貌分析、化学成分分析、金相分析、能谱分析、X射线衍射分析、电化学分析和电偶腐蚀测试等方法,对海上某生产平台增压泵出口管线短节腐蚀失效原因进行了深入研究。结果表明:增压泵出口管线短节内表面腐蚀产物主要由结构疏松的各种铁的氧化物及FeCO_(3)组成;导致增压泵出口管线短节内壁腐蚀的主要原因是以冲刷腐蚀为主和电偶腐蚀共同作用的结果。建议出口管线短节使用更加耐冲刷腐蚀的低合金钢或不锈钢,同时焊接材料选择与管线电极电位尽量接近的金属。

By means of morphology analysis,chemical composition analysis,metallographic analysis,energy spectrum analysis,X-ray diffraction analysis,electrochemical analysis and galvanic couple corrosion test,the causes of the corrosion failure of the booster pump outlet pipeline joint at an offshore production platform are studied.The results show that the corrosion products at the internal surface of the outlet pipeline flange joint of booster pump are mainly composed of various iron oxides and FeCO_(3) with loose structure,and the main reason for the corrosion is due to the combination of scour corrosion and galvanic corrosion.It is suggested to use lower alloy steel or stainless steel that is more resistant to scour corrosion for the outlet pipeline flange and choose a welding material having the electrode potential similar with that of the pipeline.