大牛地气田某输气管道内腐蚀的原因

Causes of Internal Corrosion of a Gas Pipeline in Daniudi Gas Field

采用扫描电镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)对大牛地气田某集气站外输管道内腐蚀的原因进行分析。结果表明:固态与液态腐蚀产物均呈疏松多孔结构,对金属基体的保护作用较差;腐蚀产物的主要元素为Fe、O、S、C,其中C和S元素含量超标,腐蚀产物主要由FeS、FeCO_(3)、Fe_(2)O_(3)和Fe_(3)O_(4)组成;输气管道内发生了H_(2)S、CO_(2)的协同腐蚀,H_(2)S、CO_(2)溶解于管道内沉积的凝析水后,与金属基体发生腐蚀反应,腐蚀形式主要为局部腐蚀。

The causes of internal corrosion of the external pipeline of a gas gathering station in Daniudi gas field were analyzed by scanning electron microscope(SEM),energy dispersive spectrometer(EDS) and X-ray diffractometer(XRD).The results showed that the solid and liquid corrosion products was loose and porous structures,and the protective effect on metal matrix was poor.The main elements of the corrosion products were Fe,O,S and C,and the contents of C and S elements exceeded the standard.The corrosion products were mainly composed of FeS,FeCO_3,Fe_2O_(3) and Fe_(3)O_(4).The synergistic corrosion of H_(2S) and CO_(2) occurred in the gas pipeline.H_(2S) and CO_(2) dissolved in the condensate water deposited in the pipeline and reacted with the metal matrix.The main corrosion form was localized corrosion.