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Cathodic Protection of Condensers
The condenser, also known as a condenser, is used to condense the exhaust steam from a turbine into water, which is the most important auxiliary equipment for a steam turbine generator. The water chamber of the condenser is usually made of cast iron or carbon steel, and the heat exchanger tubes are made of brass or other copper alloys. The condensing tubes may be made of aluminum bronze, white bronze, or titanium.
Cathodic protection coverage: inner wall of water chamber, head plate, and end of pipes.
The cathodic protection of the inner wall of the condenser in a power plant can be achieved by either an external current or sacrificial anode cathodic protection system. For condensers with longer protection requirements and higher conductivity of water, an external current cathodic protection system should be used. At present, most power plants use external current protection. For condensers with good corrosion protection and shorter protection requirements and lower conductivity of water, sacrificial anode cathodic protection system can be used.
The following are the advantages of using an external current cathodic protection:
1. Cathodic protection by external current can provide a continuous and adjustable protection current, which makes the various materials in the water chamber reach a protective potential and provides sufficient protection to eliminate galvanic corrosion.
2. The main protected objects on the inner wall of the condenser are the header plate, pipe sections, and water chamber, as well as the inlet and outlet pipes made of other materials. The potential difference caused by the difference in materials and the galvanic corrosion of dissimilar metals can provide a very low driving voltage for sacrificial anodes. It is difficult to eliminate the galvanic corrosion of dissimilar metals with sacrificial anodes alone, and it is difficult to control the protection current.
3. The cathodic protection power supply can monitor the effect of cathodic protection in real time, which is extremely critical for ensuring the service life of the condenser.
4. Maintenance in the later stage requires periodic replacement, which increases the maintenance and construction cost. The one-time investment in external current is larger, but from the long-term perspective, it has a higher cost-effectiveness ratio.
In summary, cathodic protection of condensers by external current system is superior to sacrificial anode system.
Cathodic Protection of Power Plant Pipelines and Other Facilities
Cathodic protection is also widely used in the following applications: protecting cooling water intake pipelines and systems for power plants, circulating water pipelines, circulating water pumps, various buried pipelines and related equipment, and the intake grilles for water source protection wells and pumping stations.
