不同NaCl浓度对油气集输管道用钢冲刷腐蚀协同作用的影响  

Influences of NaCl Concentration on the Synergistic Action of Erosion-corrosion of Steel Used in Oil and Gas Gathering and Transportation Pipelines

作　　者：李恩田[1] 张建伟 周昊[1] 杨足膺 刘雯 王磊 贾勇 LI En-tian;ZHANG Jian-wei;ZHOU Hao;YANG Zu-ying;LIU Wen;WANG Lei;JIA Yong(Jiangsu Key Laboratory of Oil-Gas Storage and Transportation Technology,Changzhou University,Changzhou 213016,China;Business School,Changzhou University,Changzhou 213016,China;Gas Transportation Management Department of Petrochina Southwest Oil and Gasfield Company,Chengdu 610000,China)

机构地区：[1]常州大学江苏省油气储运技术重点实验室,江苏常州213016 [2]常州大学商学院,江苏常州213016 [3]西南油气田公司输气管理处,成都610000

出　　处：《表面技术》2020年第5期279-284,共6页Surface Technology

基　　金：国家自然科学基金(41801194,51706024);江苏省油气储运重点实验室开放课题项目(SCZ1311700006/004)。

摘　　要：目的量化不同Cl^–浓度下的冲刷腐蚀协同作用。方法利用旋转圆柱电极实验装置,在模拟油田采出液中,通过腐蚀质量损失、形貌观测和电化学分析(包括Tafel曲线测试和阻抗谱测试等方法)得到20号钢在不同Cl^–浓度下的冲刷腐蚀规律。基于纯冲刷、纯腐蚀和冲刷腐蚀在不同Cl^–浓度下的质量损失速率和电化学拟合结果,得到纯腐蚀、纯冲刷及其相互作用对冲刷腐蚀的贡献。结果在模拟油田采出液中,当NaCl溶液质量浓度小于4.5%时,冲刷腐蚀质量损失率随Cl^–浓度的增大而增大,最高增至0.44 mg/(cm^2·h)。由于在每种Cl^–浓度下施加相同的电位保护,因此,由纯冲刷导致的质量损失变化不大。从图像来看,随着Cl^–浓度的增大,材料表面逐渐出现明显的腐蚀坑。结论Cl^–浓度对材料腐蚀有明显的促进作用,并且存在临界Cl^–浓度。冲刷腐蚀质量损失率与形貌观测有良好的一致性,且不同Cl^–浓度下的冲刷腐蚀均为电化学腐蚀-冲刷混合控制,其中电化学腐蚀占据主导地位。对于协同作用方面,随着Cl^–浓度的增加,腐蚀对冲刷的促进作用逐渐增大,而冲刷对腐蚀的促进作用先逐渐增大再减小。The paper aims to quantify the synergistic effects of erosion-corrosion at different Cl^–concentrations.The corrosion law of 20#steel under different Cl^–concentrations was obtained by means of corrosion weightlessness,morphology observation,electrochemical analysis(including Tafel curve test and impedance spectrum test)in simulated oilfield produced fluid with rotating cylindrical electrode experimental device.Based on the mass loss rates and electrochemical fitting results of pure erosion,pure corrosion and erosion-corrosion at different Cl^–concentrations,the contributions of pure corrosion,pure erosion and their interactions to the total erosion-corrosion were obtained.In the simulated oilfield production fluid,when the NaCl concentration was less than 4.5%,the erosion and corrosion quality loss rate increased with the increase of Cl^–concentration,and the highest rate increased to 0.44 mg/(cm^2·h).Since the same potential protection was applied at each Cl^–concentration,the mass loss due to erosion did not change much.It can be seen from the image that corrosion pits gradually appeared on the surface of the material with the increase of Cl^–concentration.Cl^–concentration has obvious promoting effect on material corrosion,and there is a critical Cl^–concentration.The erosion-corrosion mass loss rate is in good consistency with the observation of morphology,and the erosion-corrosion under different Cl^–concentrations is a mixed control of electrochemical corrosion-erosion,in which electrochemical corrosion dominates.As for the synergistic effect,with the increase of Cl^–concentration,the corrosion promoting effect on scour gradually increases,while the erosion promoting effect on corrosion first increases and then decreases.

关 键 词：20号钢 冲刷腐蚀 协同作用 质量损失 电化学实验 形貌观察 

分 类 号：TG172[金属学及工艺—金属表面处理]