Numerical Simulations of Factors Affecting Stray Current Corrosion on Pipeline

Abstract

Stray current can cause severe corrosion on buried steel pipelines. To investigate the corrosion effect of stray current, originating from impressed current cathode protection system of pipeline, on interference pipeline, a numerical model based on boundary elements using commercial software COMSOL Multiphysics was developed to simulate corrosion potential and stray current density distribution on interference pipeline. The model geometry was comprised of the cathodically protected pipeline, interference pipeline and an auxiliary anode. The effects of crossing angle and crossing distance of the two pipelines, output current and location of anode, soil resistivity and coating surface resistivity were investigated. The results demonstrated that the impressed current cathode protection system substantially affects the corrosion potential and current density distribution of interference pipelines in vicinity of crossing. The crossing angle and vertical distance of two pipelines have no important influence while the anode output current, anode location, soil resistivity and coating surface resistivity have significant influence to stray current corrosion on interference pipeline.