N80钢在CO_2/H_2S高温高压环境中的腐蚀行为

Analyzing electrochemical behaviors of N80 steel under the conditions of high temperature and high pressure containing CO_2/H_2S.

利用交流阻抗和极化曲线 ,在模拟含CO2 /H2 S的高温高压环境中实时监测了N80油管钢的腐蚀行为 ,辅以扫描电镜和X 衍射分析 ,探讨了CO2 和H2 S对油管钢的联合腐蚀作用。研究结果表明 :在 1 18MPaCO2 和 0 0 1MPaH2 S混合气体腐蚀环境中 ,N80钢以H2 S腐蚀为主 ,与CO2 腐蚀相比较 ,加入H2 S后腐蚀的阴、阳极反应加快 ,腐蚀产物膜具有较强的保护性 ,阻碍了反应物质的传输 ,使均匀腐蚀速率下降 ;硫化物的缺陷会导致局部腐蚀的发生 ,但FeCO3和CaCO3等二次产物的紧密填充 ,使得局部腐蚀受到一定程度的抑制。

The electrochemical behavior of N80 steel, as a function of exposure time in high-temperature/high-pressure solution with CO 2 and H 2S was investigated by electrochemical impedance spectroscopy and potentiodynamic polarization on line. SEM and X-ray analysis were also made to discuss the effect of CO 2 and H 2S on the corrosion scale. The results show that, in the simulation solution with 1.18 MPa CO 2 and 0.01 MPa H 2S, the corrosion process is controlled by H 2S, the corrosion rate of N80 steel is accelerated compared to the corrosion in the solution only containing CO 2, but the corrosion scale can protect the steel from corrosion by blocking the mass diffusion. The drawback of the sulfide films leads to pitting, but after the FeCO 3 and CaCO 3 filling in the drawback of the sulfide films and uniting well-knit, the pitting may reduce to some degree.