Cathodic protection and technology

Cathodic protection is the most effective corrosion control measure, but it is a bit of a mystery to those who are not fully familiar with it, and apparently many people feel that cathodic protection is a complicated method. In fact, the basic principle of cathodic protection is very simple, its complexity lies in the application process of cathodic protection.

The American Society of Corrosion Engineers (NACE) defines cathodic protection as reducing the corrosion rate by applying an applied electromotive force to shift the corrosion current of the electrode towards a lower oxidizing potential.

There are two main ways to use cathodic protection technology to delay the corrosion of steel structures: sacrificial anode cathodic protection and impressed current cathodic protection.

Sacrificial anode Cathodic protection is the bonding or welding of a metal with a negative potential, such as aluminum, zinc, or magnesium, on a metal structure. As the anode material is consumed, the released current feeds the protected metal structure and polarizes the cathode, thus achieving protection. Impressed current cathodic protection is a cathodic polarization of the protected metal by passing a cathodic current through an applied DC source. This method is mainly used to protect metal structures in large or high soil resistivity soils.

Cathodic protection is an effective method to control the corrosion of steel storage tanks and pipelines. It can effectively compensate for the corrosion caused by coating defects and greatly prolong the service life of steel storage tanks and pipelines. According to the data provided by a cathodic protection engineering company in America, cathodic protection is one of the most economical means to prevent corrosion of steel storage tanks from economic consideration.

Since the discovery of cathodic protection technology in 1824, cathodic protection technology has been widely used in the corrosion protection of steel structures in various fields, such as petroleum and petrochemical industries.

National regulations on cathodic protection of steel storage tanks:

UK: Cathodic protection is an effective complement to coating protection for oil tanks in corrosive environments.

Japan: High Pressure Association Petroleum Storage Tank Corrosion Protection Guidelines 1981: Cathodic protection should be provided for both new and established storage tanks.

United States: Environmental Protection Agency regulations of 1984: Coating and cathodic protection should be considered at the beginning of new oil tanks; Cathodic protection should be added to old tanks that are already coated.

3.0.5: Cathodic protection shall be adopted for the outer wall of the tank floor, and cathodic protection measures shall be generally taken for the inner wall of the tank except that it is proved by investigation that there is no need for cathodic protection