目的 寻找新型缓蚀剂,以解决碳钢在气井采出水中的腐蚀问题。 方法 以 N80 钢在 80 ℃ 气井采出水中的腐蚀为研究对象,通过极化曲线和电化学阻抗谱,研究曼尼希碱与硫脲进行复配的缓蚀效果,并探讨缓蚀协同作用机理。 结果 硫脲是一种混合型缓蚀剂,对 N80 钢的阴极过程和阳极过程都有强烈的抑制作用;曼尼希碱是一种以抑制阴极为主的混合型缓蚀剂。 二者复配后,对 N80 钢在气井采出水中的腐蚀表现出优异的缓蚀协同效应,当曼尼希碱添加量为 0 . 75% ,硫脲的质量浓度为 2 . 5 mg / L 时,缓蚀效果最好。 结论 曼尼希碱与硫脲二者复配使用时,在 N80 钢表面可能形成一种双层结构的吸附膜,内层以硫脲为主,外层以曼妮希碱为主。

Objective To find new inhibitors of carbon steel corrosion in gas-field wastewater. Methods The synergistic inhibition effect of mannich ( MABS) and thiourea ( TU) on N80 carbon steel in corrosion system of gas-field wastewater was investigated by using polarization curves and electrochemical impedance spectroscopy ( EIS) . Results The results showed that TU had strong inhibition effect on the anodic and cathodic processes of N80 steel corrosion, while MABS acted as mixed-type inhibitor preferentially restraining the cathodic process of metal. The combination of MABS and TU showed excellent synergistic inhibition effect in gasfield wastewater. When the Mannich and thiourea concentration was 0. 75% and 2. 5 mg / L, respectively, the inhibition effect was the best. Conclusion When using the combination of MABS and TU, a bi-layer inhibitor film with the inner layer of TU molecules and the outer layer of mannich molecules was formed on the N80 steel surface.