A Real-Time AC/DC Measurement Technique for Investigation of AC Corrosion of Pipelines and Its Effect on the Cathodic Protection Effectiveness

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• 作者：Luyao XuY.Frank Cheng
• 会议时间：2013-09-01
• 关键词：pipeline corrosion ; alternating current ; data acquisition ; cathodic protection potential
• 作者单位：Department of Mechanical and Manufacturing Engineering University of Calgary Calgary,Alberta,T2N 1N4 Canada
• 母体文献：2013中国国际管道会议暨第一届中国管道与储罐腐蚀与防护学术交流会论文集
• 会议名称：2013中国国际管道会议暨第一届中国管道与储罐腐蚀与防护学术交流会
• 会议地点：廊坊
• 主办单位：中国腐蚀与防护学会
• 语种：chi

摘要

In this work, a real-time AC/DC (altemating current/direct current) signal data acquisition (DAQ) technique was developed, which enabled separation of AC and DC components from the recorded total voltage during the AC corrosion measurements.Mechanistic information about the steel corrosion in the presence of AC interference was obtained.Furthermore, the effects of AC on the performance of cathodic protection (CP) and the CP potential readings were determined by the developed DAQ.It was found that the presence of AC decreased the CP effectiveness.Moreover, the AC would shift CP potential from the designed value, generating mis-leading information on the CP performance.Under a mild CP potential, e.g.,-0.85 V (saturated calomel electrode, SCE), the AC would shift the DC potential of the steel negatively due to an enhanced dissolution of steel upon the AC application.When the CP potential was sufficiently negative, e.g., -1 V (SCE), the DC potential of the steel was shifted positively, but the AC application would not be able to affect the steel corrosion at a detectable level.