摘要
基于长输管线三层聚乙烯(3PE)防腐层失粘剥离现场开挖调查的情况,构建剥离防腐层下管道表面微区环境腐蚀模拟研究实验装置,研究华南酸性土壤环境条件剥离防腐层下管体表面的阴极保护和微区环境特征,采用微电极技术监测剥离区管线钢表面的局部电位和环境p H值的变化。结果表明,剥离区管线的有效保护距离随阴极保护电位负移而增加;在高电阻率酸性土壤环境中,剥离防腐层下的阴极保护仅限于破损点附近,剥离区深处管体处于自腐蚀状态;剥离防腐层下阴极保护有效性及其屏蔽程度可由剥离防腐层下微区溶液p H值判定。
Based on disbondment failure cases of three layer polyethylene (3PE) coating in excavation on some long-distance pipelines, a simulating experimental apparatus was constructed to study cathodic protection performance and micro-environmental features in acidic soil stripping. The potential of pipeline and pH of the micro-environment was monitored by the microelectrode technology. The results show that the effectiveness distance of cathodic protection (CP) increases with the negative shift of CP potential; CP current initiates high pH environments on the surface of pipeline steel. In the high resistivity acidic soil, CP is limited to the opening defect area, whereas the pipeline surface undergoes free corrosion beneath the deep disbondment. The CP effectiveness and shielding effect of the coating disbondment can be estimated by measuring pH of the local electrolyte under disbonded coatings.
作者
于利宝
徐兆东
孙海星
闫茂成
孙成
于长坤
YU Li-bao;YAN Mao-cheng;SUN Cheng;YU Chang-kun;XU Zhao-dong;SUN Hai-xing(National Engineering Research Center for Corrosion Control, Environment Corrosion Center, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China;Dalian Oil & Gas Branch Anshan Transportation Station, Petrochina Pipeline Company, Anshan 114016, China;Southwest Pipeline Company, Petrochina Co., Ltd. Chengdou 600410, China)
出处
《全面腐蚀控制》
2016年第11期41-44,共4页
Total Corrosion Control
关键词
防腐层
油气管线
阴极保护屏蔽
电位分布
coatings
oil/gas pipeline
cathodic protection shielding
potential distribution
