Cathodic protection of port terminals

The anti-corrosion method of the port and wharf is the combined anti-corrosion method of covering layer and cathodic protection. Cathodic protection can also be adopted for the underwater area, and the covering layer method can be adopted for the area above the average low tide line. The cathodic protection can adopt the sacrificial anode cathodic protection method, or the forced current cathodic protection method, or a combination of the two. It mainly depends on the protection effect and the combined effect of the structure, corrosive environment, power supply, equipment reliability, operation management and other factors. Its economy.

The coating plays a role of anti-corrosion protection, but only the part located in the mud zone during installation will lose about 50%, and in the splash zone and underwater zone, it will lose 1-2% every year. Generally speaking, in these areas The corrosion depth of bare steel can reach 50μm-300μm. Factors such as water composition, oxygen concentration, sea creatures and sea water speed will also accelerate the corrosion and thinning of steel materials.

Cathodic protection is a technology that uses electrochemical methods for corrosion protection. It uses electrical technology to make the potential of each point on the metal surface consistent, thereby slowing down corrosion. Cathodic protection can extend the operating life of facilities, reduce maintenance costs, and ensure that the dock and the There are two ways to achieve cathodic protection for the continuous operation of breakwaters, that is, sacrificial anode cathodic protection and impressed current cathodic protection.

The sacrificial anode cathodic protection method is to connect two metals with different activities in the same electrolyte. The metal with strong activity loses electrons and is corroded, and the metal with poor activity is protected by electrons. In this process, the active metal is corroded, so it is called sacrificial anode cathodic protection. Generally, aluminum alloy sacrificial anode and zinc alloy sacrificial anode are used in seawater; the cathodic protection method is impressed current cathodic protection, which is arranged through the anode In the seawater environment, the current flows from the seawater medium to the protected structure, and returns from the confluence point to the power equipment. Since the current is forced to flow to the protected structure, it is also called forced current cathodic protection.

Taicang CapitaLand can provide sacrificial anode cathodic protection, impressed current system or a combination of cathodic protection solutions for newly built or operating port terminals, breakwaters, etc. Bogo is committed to meeting various environmental conditions with international and domestic design standards. , Before designing, we must carry out detailed engineering calculations according to national or international standards, which can make the anti-corrosion protection system in the mud and underwater areas more effective.

The table below shows the corrosion rate of different areas. Cathodic protection can reduce the corrosion rate of underwater and submud areas by nearly 95%. Special precautions need to be taken in the splash zone and atmospheric zone. It is recommended to use a combination of cathodic protection system, coating and PE sheath to protect the piles in all aspects.

Average corrosion value of steel sheet pile and steel pile:

The data required for the design is as follows:

• Types  of piles •  Length of piles • Design life of the system  • Length of  seabed and lower piles  • Specifications of pile coatings  • Continuous welding methods  • Layout drawings  • Dangerous area divisions  • Facilities isolated from other structures  • Types of power sources Availability  • Existing cathodic protection system