Method
Method Principle
The active cathodic protection with impressed current constitutes the most reliable corrosion protection system for boilers. This method has been applied for more than 50 years and is considered the only method of protection of steel structures in any form of corrosive environment. In addition to boilers, this method is also applied for protection of fuel transfer pipelines, ships, oil drilling platforms, potable water distribution networks, steel tanks, etc. The impressed current cathodic protection method is based on the uniform distribution of predetermined direct current voltage on the structure to be protected. The structure steel surface is connected to the source cathode and therefore it is entirely protected.
For the same reason however current distribution is not feasible on pipe networks, for the protection of which the system requires the combination with a respective electrolytic aluminum dissolution unit. The aluminum ions that are imparted in water are strong corrosion inhibitors and form a thin protective coherent layer of aluminum and silicon oxides with maximum thickness of 0,1 to 0,2mm along the inner surface of steel pipes. Corrosion protection is achieved, while at the same time the formation of carbonate deposits (scale) is prevented.
Description
Description
The system consists of electronic control units that induce current between the boiler tank walls and special anodes made out of titanium coated with mixed oxides (Mixed Oxide Titanium Anodes). These anodes are installed on the interior of the boiler tanks, based on a particular design that is modified depending on the requirements of each system in regards to the anode shape (rods, wire, etc.), and the installation location. The installation is performed with the use of equivalent connectors, specifically designed and built out of titanium, stainless steel and Teflon.
Corrosion protection is controlled with the use of an Ag/AgCl reference electrode from Teflon which is installed in a particular location inside the boiler tank, according to each system design. The impressed current allows for the potential of the boiler to be maintained at a level lower than -800mV vs Ag/AgCl value, which is the specified limit in all international standards (ASTM, DIN, BS) for the achievement of complete steel corrosion protection.
Warranty
Warranty
The impressed current cathodic protection method has been applied for more than 50 years on all structures that are subjected to intensely corrosive environments (ships, platforms, pipelines, cooling systems, boilers) and constitutes the only active corrosion protection method available for steel structures.
In regards to the method of electrolytic aluminum dissolution, it is noted that the very first system was installed in 1924 and is still in operation. Nowadays, more than 40.000 such systems have been installed worldwide. Planning authorities in Denmark, where the method was invented the planning authorities consider erroneous the omission of electrolytic aluminum dissolution corrosion protection on the hot water distribution pipe network in new buildings.
Cathodic Protection
Boiler Cathodic Protection
Boiler cathodic protection systems are fully automated and provide a series of operation condition indications for each boiler (impressed current, voltage, potential/degree of protection) via an LCD digital screen which is integrated on the central control unit. Additionally, the possibility of monitoring and automatic adjustment for the optimum operation of the system is provided, when and if necessary, with shipment and programming of a special electronic control card that is connected directly and without interference on a specified location on the face of the central control unit.
The anticipated operational life of anodes exceeds 20 years, virtually ensuring an unlimited operational life for the boilers under protection.
