Modeling Pipeline Corrosion within a Disc-Shaped Crevice for Various Cathodic Protection Levels at the Holiday and the Effect of Crevice Geometry

Abstract A deterministic model was developed to predict the pipeline corrosion rate within a disc-shaped crevice in the presence of oxygen (O2) and cathodic protection (CP). The model results from modification of a previous model that we developed to describe pipeline corrosion in a rectangle crevice. Using this disc crevice corrosion model (DCCM), the effect of the geometrical parameters of the crevice (crevice gap, the holiday size and the thickness of the coating) on the corrosion rate, the effect of various levels of CP and the effect of temperature on the crevice corrosion rate and potential were investigated. O2 transport through both the holiday and the disbonded coating was included. This work provided insight into the mechanisms of CP in protection of pipelines and the significance of crevice geometry and temperature to the DCC rate.