为研究延长气田CO₂环境中醋酸对X65湿气管线顶部腐蚀的影响,通过自制顶部腐蚀模拟实验装置以及动电位极化曲线和电化学阻抗法,采用挂片失重、扫描电镜分析手段研究了CO₂环境中醋酸对X65电化学腐蚀行为的影响。结果表明,腐蚀介质pH与HAc质量浓度呈对数函数变化,HAc质量浓度升高则腐蚀电流密度变大,阴极反应增强,腐蚀产物膜的溶解性增加,易产生孔隙,诱发氧浓差腐蚀。不同HAc质量浓度下,EIS高频容抗弧与界面双电层的行程有关,EIS低频斜线与腐蚀介质扩散有关。内层腐蚀产物膜与基体结合界面凌乱。HAc质量浓度增加,顶部腐蚀速率增加,腐蚀速率与HAc质量浓度呈对数函数关系。

In order to clarify the influence of acetic acid on the corrosion at top of X65 steel-based wet gas pipeline in a CO₂ environment in Yanchang gas field,the effects of acetic acid on the electrochemical corrosion behavior of X65 steel in a CO₂ environment are studied by using a self-made corrosion simulation device,potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS).Results show that there is a logarithmic function change between the pH of the corrosion medium and the concentration of acetic acid.The increase of acetic acid concentration leads to an increase of the corrosion current density,which enhances the cathodic reaction,therefore the solubility of corrosion product film increases,the pores are easy to be formed,inducing corrosion generated by difference of oxygen concentration.Under different acetic acid concentrations,high frequency capacitive reactance arc of EIS has a relationship with the travel of double electric layer,and the low frequency slope of EIS is related to the diffusion of corrosion medium.The interface between the inner corrosion product film and the substrate is disordered.The corrosion rate at the top of X65 steel pipeline increases with the increase of acetic acid concentration,and there is a logarithmic function relationship between corrosion rate and acetic acid concentration.

封子艳(1982-),女,博士,副教授,主要研究领域为油田化学,fengziyan1982@163.com