Optimizing the Required Cathodic Protection Current for Pre-Buried Pipelines Using Electrochemical Acceleration Methods

• Published in: Materials Vol. 14; no. 3; p. 579
• Main Authors: Chung, Nguyen-Thuy, Hong, Min-Sung, Kim, Jung-Gu
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 26-01-2021; MDPI
• Subjects: applied current density; buried pipelines; Buried pipes; Carbon steel; Cathodic protection; Corrosion; Corrosion currents; Corrosion prevention; Current density; electrochemical acceleration test; Electrochemical impedance spectroscopy; Electrode polarization; Electrodes; Empirical equations; Experiments; Microscopy; Optical microscopy; Pipelines; required current; rust layer; Soil investigations; Underground corrosion; applied current density; required current; electrochemical acceleration test; rust layer; cathodic protection; buried pipelines
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma14030579

Several corrosion mitigation methods are generally applied to pipelines exposed to corrosive environments. However, in the case of pre-buried pipelines, the only option for corrosion inhibition is cathodic protection (CP). To apply CP, the required current should be defined even though the pipeline is covered with various oxide layers. In this study, an electrochemical acceleration test was used to investigate the synthetic soil corrosion of a pre-buried pipeline. Potentiodynamic polarization experiments were first conducted to ascertain the corrosion current density in the environment, and galvanostatic measurements were performed to accelerate corrosion according to the operating time. In addition, corrosion current density and the properties of the rust layer were investigated via potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) tests. The variation in surface corrosion was subsequently analyzed via optical microscopy (OM) and X-ray diffraction (XRD) measurements. Finally, an empirical equation for the optimized CP current requirement, according to the pipeline service time, was derived. This equation can be applied to any corroded pipeline.