Definition - What does Cathodic Protection mean?
Cathodic Protection is a technique of minimizing the rate of corrosion on the outer surface of cost-intensive equipment such as pipelines, storage tanks, vessels, etc., with the help of electrochemical means. To enable this, a sacrificial metal or element is used as an anode and the metal structure that needs to be protected is used as the cathode. In the oil and gas industry, cathodic protection is primarily used to safeguard the distribution pipeline network and underground steel storage tanks from corrosion.
Petropedia explains Cathodic Protection
Cathodic protection (CP) is one of the basic and important steps during the laying of an oil and gas pipeline. Cathodic protection protects the cost intensive oil & gas infrastructure from corrosion by making it a cathode. For example, to make underground storage tank a cathode, an anode is attached to it and soil or water works as an electrolyte. Natural water, Soil, seawater, are considered as natural sources of electrolytic conducting environment
Cathodic protection essentially reduces the corrosion rate of a metallic structure by reducing its corrosion potential. It is the key to protecting and extending the life of metallic equipment.
Cathodic protection can be achieved in two ways:
- The use of galvanic (sacrificial) anodes - Galvanic anode systems employ reactive metals as auxiliary anodes that are directly electrically connected to the steel to be protected.
- Impressed current - Impressed current systems employ inert anodes and use an external source of DC power to impress a current from an external anode onto the cathode surface.