In this work, the effectiveness of cathodic protection (CP) at corrosion defects on an X100 steel pipeline was investigated both experimentally and numerically. A finite element model was developed to simulate distributions of local potential and anodic/cathodic current density inside the defect. Results demonstrated that there is a non-uniform potential and current distribution at corrosion defects. The CP is shielded, at least partially, at the defect, especially at its bottom. This effect is enhanced with increasing depth and decreasing width of the defect. Empirical equations are derived to enable determination of the potential drop inside defect, and thus the potential and current density distributions in the defect, especially at the defect bottom, while CP is applied on the steel. They are capable of assessing conveniently for industry the CP effectiveness at defects and the further corrosion scenario on pipelines. Empirical equations are derived to enable calculation of CP effectiveness at corrosion defects, providing industry recommendations for accurate assessment of further corrosion allowance and remaining life of pipelines in the field.
Experimental and numerical studies of effectiveness of cathodic protection at corrosion defects on pipelines
Experimentelle und numerische Untersuchungen über die Wirksamkeit des kathodischen Schutzes an Korrosionsdefekten von Pipelines
Corrosion Science ; 78 ; 162-171
2014
10 Seiten, 17 Bilder, 2 Tabellen, 38 Quellen
Article (Journal)
English
Pipeline , unlegierter Stahl , Oberflächenschaden , Korrosionsschaden , kathodischer Korrosionsschutz , Leistungsvermögen , numerische Modellierung , Potenzialverteilung , Stromdichte , Finite-Elemente-Simulation , Bohrloch , Polarisationskurve , elektrochemische Reaktion , Tiefenprofil (Abstand unter Oberfläche) , Fehleranalyse , geometrische Form
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