Abstract In this work, the inhibition efficiency of an imidazoline derivative corrosion inhibitors in CO2 corrosion of carbon steel was investigated in the presence of iron carbonate scale and hydrogen sulfide. The use of corrosion inhibitors is one of the most common controlling techniques for CO2 corrosion of carbon steel in oil and gas industry. One of the imidazoline derivatives was used as a corrosion inhibitor which protects the surface through the film formation mechanism. The investigation material was API 5L X65 carbon steel which was cut from a wet gas transmission pipeline. The internal surface of the pipe was covered with iron carbonate as corrosion product. In order to investigate the inhibitor efficiency, Tafel polarization and electrochemical impedance spectroscopy were done in CO2-saturated 3.5 wt.% sodium chloride solution. According to the results, the existence of iron carbonate film reduced the inhibition efficiency. Furthermore, it was found that in the presence of H2S gas, the inhibition efficiency was decreased due to the decrease in inhibitor adsorption on the surface.

中文翻译：

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碳酸铁水垢存在下缓蚀剂对碳钢CO2腐蚀效率的考察

摘要 本工作研究了咪唑啉衍生物缓蚀剂对碳钢CO2腐蚀在碳酸铁垢和硫化氢存在下的缓蚀效果。缓蚀剂的使用是油气工业中碳钢CO2腐蚀最常用的控制技术之一。其中一种咪唑啉衍生物用作腐蚀抑制剂，通过成膜机制保护表面。调查材料为 API 5L X65 碳钢，从湿气输送管道上切割下来。管子的内表面覆盖有作为腐蚀产物的碳酸铁。为了研究抑制剂的效率，在 CO2 饱和的 3.5 wt.% 氯化钠溶液中进行了 Tafel 极化和电化学阻抗谱。结果表明，碳酸铁膜的存在降低了缓蚀效率。此外，发现在 H2S 气体存在下，由于抑制剂在表面上的吸附减少，缓蚀效率降低。