高温高压CO_(2)/O_(2)共存流体中N80钢腐蚀特性分析

Corrosion Characteristics of N80 Steel in High-temperature High-pressure CO_(2)/O_(2) Coexisting Fluid

在高温高压釜中进行CO_(2)和O_(2)共存流动液体环境中N80油管钢的腐蚀实验,采用失重法测量腐蚀速率,扫描电镜(SEM)和X射线衍射仪(XRD)测试腐蚀表面形貌和成分的方法,得到N80钢在流动多元热流体中的腐蚀规律与形貌特征。实验结果表明:在CO_(2)和O_(2)共存环境下,N80钢腐蚀以均匀腐蚀为主伴有部分局部腐蚀,腐蚀速率呈现随温度的升高先快速增大后缓慢减小的趋势;200℃时生成的腐蚀产物以碳酸亚铁和铁的氧化物为主,该腐蚀产物膜更为致密,腐蚀速率更小;在CO_(2)和O_(2)共存环境下相比于介质中仅含CO_(2)或O_(2)环境下N80钢的腐蚀程度更严重。

The corrosion test of N80 tubing steel in CO_(2)/O_(2)coexisting fluid was carried out in a high-temperature high-pressure autoclave.Its corrosion rate was measured by weight loss method,and the surface corrosion morphology and composition were measured by scanning electron microscope(SEM)and X-ray diffraction(XRD).The results show that the corrosion of N80 steel is mainly uniform corrosion with a small amount of local corrosion,and the corrosion rate increases rapidly at first and then decreases slowly with the increase of temperature in CO_(2)/O_(2)coexisting environment.The corrosion products formed at 200°C are mainly ferrous carbonate and iron oxides,and the product film is denser and the corrosion rate is smaller.The corrosion of N80 steel in CO_(2)/O_(2)coexisting environment is more serious than that in the medium containing CO_(2)or O_(2)only.