Design of Sacrificial Cathodic Protection System for Crude Oil Pipeline (Part-1 Theoretical Aspects)

Cathodic protection (CP) is a technology used for controlling corrosion by making a metal surface the cathodic side of an electrochemical cell. This paper discusses the methods for designing sacrificial cathodic protection and applies this method to evaluate two case studies of cathodic protection. In the first case, there is a pipe constructed from API 5L-X70 steel, with a diameter of 1 m and a length of 6 m, extending over a distance of 100 m. In the second case, a pipe made from API 5L-X60 steel has a diameter of 0.50 m and a length of 8 m, extending for a distance of 450 m. The findings indicated that as the diameter, length, and extension of the pipe increase, the required corrosion protection current also rises. Consequently, the number of sacrificial anodes required for cathodic protection and associated costs also increases. Furthermore, the study revealed an inverse relationship between sacrificial electrode current and electrode lifespan; as the electrode current increases, the lifespan of the electrode decreases, necessitating periodic replacement of the electrode.