Impressed current cathodic protection technology for inlet equipment

The main equipment of the inlet water of circulating water system in power plant includes gate and gate guide groove, coarse grid, coarse grid guide groove and rotating filter screen. Various materials used in each equipment (carbon steel, nickel-chromium cast iron, stainless steel), various materials themselves have certain corrosion, and at the same time, different metals electrically connected together in seawater will also produce galvanic corrosion, which further aggravates the corrosion speed of each equipment. At present, the protection of water inlet equipment generally adopts the combined protection of seawater corrosion resistant coating and aluminum (zinc, iron) alloy sacrificial anode. But strict seawater coating construction, protection of reliability is not high, protection of short time (1 ~ 2 years), the other surface area is larger, each device provided by the sacrificial anode protection current is limited, can't reach the equipment surface, exist to protect the corner, and protection potential beyond measure, protection current cannot adjust, protect life cannot predict, If the preliminary survey is not accurate, the sacrificial anode system can not be adjusted after the design and installation, and this defect cannot be made up.

Impressed current because of the adjustable current, can be adjusted according to the size of the required current, so it is more used in the need of large current, more complex material system. Impressed current cathodic protection technology for equipment between water inlet is a kind of current anti-corrosion system for equipment in area with high protection reliability and long service life.

The number of mixed metal oxide (MMO) auxiliary anodes is at least one. The electrode support is embedded in the concrete structure or welded on the equipment, and then the MMO auxiliary anode is fixed on the electrode support with a fixing fixture and bolts. High purity zinc or Ag/AgCl reference electrode is installed on the inlet channel wall, the number of which is at least one. The electrode bracket is embedded in the concrete structure or welded on the equipment, and then the reference electrode is fixed on the electrode bracket with a fixing fixture and bolts. The system is equipped with at least one power controller, and the power controller is equipped with two modules, each module can independently control at least one MMO auxiliary anode; The system is equipped with at least one junction box, which leads the auxiliary anode and reference electrode cables as well as the cathode wires (ground or measuring wires) to the ground. At least one anode wire, at least one reference electrode wire, at least one zero negative wire and at least one cathode wire to the corresponding terminals of the junction box, and finally into the power supply controller. The cables attached to the MMO auxiliary anode and the high purity zinc reference electrode and the zero-negative and cathodic grounding cables connecting the equipment in the area are collected through the junction box and connected to the corresponding contacts of the power control instrument to form the circuit of the current anti-corrosion system. Adjust the output voltage and output current of the power control instrument to make the measured potential 

(1) The implementation of current corrosion prevention system for regional equipment, reasonable design, can make up for the deficiency of the early survey of the loopholes, easy installation, comprehensive service life is long (30 years);

The output voltage and current can be adjusted, and can realize automatic control with the change of process parameters and external conditions;
(3) The protection current can reach all the surface of the equipment, there is no dead Angle protection, improve the reliability of the equipment operation, save maintenance costs.
(4) The equipment in the region is protected as a whole, which can effectively prevent the galvanic corrosion formed between each equipment due to the different protection potential between each equipment in the region.

Impressed current cathodic protection system for inlet equipment

1.Cathodic protection system for inlet equipment of Bali Phase I 3×142MW coal-fired power plant project

2.Cathodic protection system for inlet equipment of Hasyan Clean Coal-fired Power Plant Phase I (4x600MW NET) project in Dubai
3.Cathodic protection system for inlet equipment of Vietnam Coastal Phase III Expansion Power Plant Project