Cathodic protection of marine engineering

The ocean is a harsh corrosive environment. Corrosion is a key factor affecting the service performance and service life of marine engineering structures. The combination of cathodic protection and coating is an effective method to prevent corrosion of metal structures in seawater. According to the protection current method provided Different, cathodic protection is divided into two methods: sacrificial anode and impressed current cathodic protection. The sacrificial anode method is simple and reliable, but the amount of anode material is large, and the design is more precise. The impressed current cathodic protection method can realize automatic control, and the output can be adjusted automatically. The magnitude of the current makes the surface of the protected structure in the set protection potential range.

Impressed current cathodic protection:

• To calculate the protected area of the protected body, in addition to calculating the area of immersion in sea water and mud below the average low tide level, the area of the tidal range and the area of the accessory structure should be calculated together.

• Calculate the protection current: Calculate the protection current required by the cathodic protection system according to the protection area and the initial protection current density or the maximum protection current density, and take 1.25-1.5 times as the total current demand.

• Selection and quantity of auxiliary anodes: auxiliary anodes used for forced current cathodic protection of port terminals include: high silicon cast iron anodes and noble metal oxide anodes.