耐高温缓蚀剂的缓蚀性能和机制研究

Performance Evaluation and Mechanism Investigation of High Temperature Resistant Corrosion Inhibitors

采用挂片失重法、扫描电镜、电化学法等研究了有机咪唑啉季铵盐型缓蚀剂IN6及其与缓蚀增效剂复配体系HTCI在130~200℃下含CO2模拟油田矿化水中对Q235钢等钢材的缓蚀性能,分析了缓蚀剂在钢片表面的吸附行为,探讨了缓蚀剂对腐蚀反应动力学的影响和缓蚀机制。结果表明,缓蚀剂IN6和HTCI在高温条件下均表现出良好的缓蚀效果,缓蚀剂IN6在高温170℃和质量浓度100 mg/L时的缓蚀率为83.5%,缓蚀剂HTCI在200℃下和质量浓度575 mg/L时的缓蚀率可达到85.5%。缓蚀剂在钢片表面的吸附符合Langmuir吸附等温式,吉布斯吸附自由能小于-40 kJ/mol,这使得缓蚀剂分子膜能够在高温条件下将腐蚀介质与钢材表面隔离,提高了腐蚀反应的活化能,并同时抑制阳极反应和阴极反应的进行,表现出优异的高温缓蚀效果。

The corrosion inhibition performance of organic imidazoline quaternary ammonium salt corrosion inhibitor IN6 and the compoud system HTCI of it with synergist to Q235 and other steel materials in simulated oilfield mineralized water containing CO2 at 130~200℃is evaluated by means of weight loss method,scanning electron microscope(SEM)and electrochemical analysis.The adsorption behavior of the corrosion inhibitor on steel was analyzed and its corrosion inhibition mechanism was discussed.It is shown that both IN6 and HTCI show good corrosion inhibition effect at high temperature.The corrosion inhibition efficiency of IN6 of 100 mg/L is 83.5%at 170℃,and the corrosion inhibition efficiency of HTCI of 575 mg/L is 85.5%at 200℃.The adsorption of corrosion inhibitors on the surface of the steel is in accordance with Langmuir adsorption isotherm,and Gibbs adsorption free energy is less than-40 kJ/mol,which makes the corrosion inhibitor molecular film isolate the corrosion medium from the steel surface at high temperature,improves the activation energy of corrosion reaction,and inhibits the anodic reaction and cathodic reaction so that the corrosion inhibitors show excellent high-temperature corrosion inhibition performance.