CO_(2)体系下X70天然气管线钢的电化学腐蚀行为研究  

Study of Electrochemical Corrosion Behavior on X70 Natural Gas Pipeline Steel under CO_(2)System

作　　者：韩晓龙 王毅 吴鑫 张霁 HAN Xiaolong;WANG Yi;WU Xin;ZHANG Ji(Karamay Fucheng Natural Gas Co.,Ltd.,Karamay 834008,China)

机构地区：[1]克拉玛依市富城天然气有限责任公司,新疆克拉玛依834008

出　　处：《材料保护》2024年第5期83-89,151,共8页Materials Protection

摘　　要：基于新疆某油田天然气输送管线采出水模拟环境,采用电化学测试方法和扫描电子显微镜等分析方法,研究了X70管线钢在4种不同CO_(2)压力下的电化学腐蚀行为。结果表明:在高含氯离子的模拟采出水溶液中,电化学阻抗谱(EIS)和极化曲线均表明X70钢试样的腐蚀程度随着CO_(2)压力的增加(0.5,1.0,2.0,3.0 MPa)变得越来越严重。失重实验结果表明X70钢试样的腐蚀速率随着CO_(2)压力的增加而增加,压力为3.0 MPa时腐蚀速率最大,为2.5739 mm/a。XRD结果表明腐蚀产物主要是FeCO_(3)。扫描电镜结果显示,试样表面的点蚀现象随CO_(2)压力的增加变得越来越严重,试样表面变得越来越粗糙。这些结果的出现归因于高压CO_(2)的作用和高浓度Cl^(-)加剧点蚀的作用。由此可以发现,高CO_(2)和Cl^(-)对X70管线钢具有严重的破坏作用。这项工作为预防这种类型的腐蚀提供了借鉴与指导。The electrochemical corrosion behavior of X70 pipeline steel under four different CO_(2)pressures was investigated by electrochemical test methods and scanning electron microscope analysis,based on the simulated environment of the extracted water of natural gas transmission pipeline in an oilfield of Xinjiang.Results showed that in simulated extracted water solutions with high chloride ion content,the electrochemical impedance spectra(EIS)and polarization curves indicated that the corrosion of X70 steel specimens became increasingly severe with increasing CO_(2)pressure(0.5,1.0,2.0,3.0 MPa).The results of the loss-in-weight experiments showed that the corrosion rate of the X70 steel specimens increased with increasing CO_(2)pressure,with a maximum corrosion rate of 2.5739 mm/a at a pressure of 3 MPa.In addition.the XRD results indicated that the corrosion products were mainly FeCO_(3).The SEM results showed that the pitting on the surface of the specimen became increasingly severe with increasing CO_(2)pressure,and the surface of the specimen became increasingly rough.These results were attributed to the effect of high pressure CO_(2)and pitting exacerbated by high Cl^(-)concentrations.Hence,it could be found that high CO_(2)and Cl^(-)had a serious damaging effect on X70 pipeline steel.This work provided reference and guidance for the prevention of this type of corrosion.

关 键 词：X70钢 天然气管线 二氧化碳腐蚀 点蚀 氯离子 

分 类 号：TG172[金属学及工艺—金属表面处理]