CO2/H2S腐蚀体系中咪唑啉季铵盐与3种阳离子表面活性剂间的缓蚀协同效应

Synergistic Inhibition Effect of Imidazoline Ammonium Salt and Three Cationic Surfactants in H2S/CO2 Brine Solution

采用分子动力学模拟技术对CO2/H2S腐蚀体系中咪唑啉季铵盐(IAS)与3种阳离子表面活性剂间的缓蚀协同效应进行了预测,并通过失重法、极化曲线测试、XPS分析等对预测结果进行验证,同时探讨了缓蚀协同机理。结果表明,IAS与十二烷基三甲基溴化铵(DTAB)、十四烷基三甲基溴化铵(TTAB)间存在较好的缓蚀协同效应,所形成的复合缓蚀剂属于以抑制阳极为主的混合型缓蚀剂;XPS分析结果表明,复合缓蚀剂中起主要缓蚀作用的物质可能为IAS,而表面活性剂则起到填补缓蚀剂膜层缺陷的作用,不同复配体系协同效应的差异,可能与缓蚀剂分子的空间位阻有关。

The synergistic inhibition effect of imidazoline ammonium salt(IAS)coupled respectively with three cationic surfactants in H2S/CO2 brine solution was predicted by molecular dynamic simulation technology.The predicted results were verified for Q235 steel in 3.5%NaCl solution by means of mass loss method,potentiodynamic polarization measurement and XPS analysis.Results show that the combination of IAS with dodecyl trimethyl ammonium bromide(DTAB)or tetradecyl trimethyl ammonium bromide(TTAB)all presents good synergistic inhibition effect.The complex corrosion inhibitors are mixedtype inhibitor.From XPS results,it follows that during the corrosion process,the IAS might mainly play the role in the formation of inhibition film on the Q235 steel surface,while the surfactant could mainly fill in the defects of the forming corrosion inhibition film.Possibly,the difference in synergistic inhibition effect for different complex inhibitors may be related to the steric hindrance of inhibitor molecules.