Decades Of Success For Alocit With Seawater Intake Pipes

Alocit
April 05, 2022
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SLP pipes at a coal fired power plant in Chungcheongnam-do province in Korea were treated with Alocit from 0.5m above the water level to 1.0m below the surface.

Seawater, abrasion and marine growth are not best friends with steel so it’s hardly surprising that seawater intake pipes are notoriously difficult to protect from corrosion.

For nearly 20 years Korean contractor Zinga Korea has been using Alocit coatings and has now been given exclusive distribution in Korea.

Zinga has been using approved Alocit coatings to repair and protect the power generating facilities and steel structures of five Korean coal-fired power generating companies, all of which respectively operate five to six power plants.

All these power plants rely on saltwater intakes for cooling systems where a combination of saltwater, oxygen and abrasion makes the steel surfaces of the intake pipes highly susceptible to corrosion.

Treatment to damaged areas is often difficult because many coatings are not suitable for application to wet or submerged surfaces, an environment where Alocit excels with its capacity to even be applied under water by divers.

Many of these areas are also environmentally sensitive, an area where Alocit stands out from many competitors with coatings containing no VOCs and suitable for application in the most sensitive of environments.

At the same time Alocit has proven effective in retarding the growth of zebra mussels which clog power plant water intakes.

As far back as 2007 Zinga Korea’s Mr. Young Kwon Nam wrote to Alocit to commend the company’s success with Alocit.

We have made wide use of Alocit products, namely Alocit 28.14 and Alocit 28.15, for longer life of the steel structures of our customers, and Alocit is one of the best known effective anti-corrosion coatings for steel structures vulnerable to corrosion by salty water,

Mr Nam wrote.

He said Zinga Korea had been lining and repairing insides of sea water intake pipes since 2005.

Zinga has carried out a wide array of Alocit projects including a number that had stood the test of time going back 25 years.

These include:

2003

In 2003 Alocit was applied to 192 sheet pilings for the Incheon Inner Harbour Lock Gate in Korea. Half of the 1.5m piles were immersed and exposed depending on the water level with the lower half usually immersed in seawater. Water temperatures varied from 13C to 15C in the middle of November to 6C to 8C in the middle of December. Surfaces were sandblasted prior to application of two coats of Alocit 28.15 by brush.

2005

Repair of anti-corrosion lining for CWP discharge pipes – before.

Repair of corroded steel pipe sufaces – after.

In 2005 Alocit was used in the coating repair of SLP pipes at the Dang-Jin coal fired power plant in Chungcheongnam-do province in Korea. The treatment area covered the area from 0.5m above the water level to 1.0m below the surface. Surfaces of the steel pipes used for cooling systems had been corroded by sea water at the coal-fired power plant. Surfaces were covered with extensive marine growth. The surface was cleaned by power tools and sand blasted to thoroughly remove rust and contaminants before applying Alocit 28.15 by brush to surfaces both above and below the waterline.

2006

In 2006 Alocit was used for the coating repair of a discharge line of seawater circulation systems at the Pyeong-taek coal-fired power plant in Gyeong-gi province using Alocit 28.15.

In 2006 Alocit 28.15 was used by Zinga at the Honam coal-fired power plant where a fiberglass reinforced plastic lining in a steel waterbox structure had failed after immersion in seawater allowing corrosion to take hold.

2005

Corroded vertical steel pipe surfaces.

Divers apply a first coat of Alocit 28.15.

Divers apply a second coat of Alocit 28.15.

The surface 18 months after being treated with Alocit.

In 2005 the Hanvit Nuclear Power Plant was experiencing severe corrosion of vertical steel pipe surfaces by sea water from condensers in a discharge line of a cooling seawater system, accelerated by cavitation corrosion caused by vertically falling water creating air bubbles. After thorough power tool cleaning, Alocit 28.15 was applied by divers after filling potholes and pinholes with underwater repair putty.

Mr. Nam said in his letter that the petrolatum anti-corrosion systems which had been very popular in Korea for decades were failing all over the nation because of its vulnerability to defects in adhesion, which are very hard to see following application.

When the failure of the petrolatum system is observed, it is too late for repair, but all the steel structures should be refurbished extensively as one of the Korean TV broadcasting companies witnessed by inspecting the piles of the Gwang-ahn Bridge in 2005 where a petrolatum system was applied in 2002.

By contrast Mr. Nam said due to its adhesion strength, robustness, ease of application underwater and effectiveness, Alocit coatings had been approved and were proving successful in the Korean market.

Trial Application - Incheon

Scraping - Incheon

Completed - Incheon

Rust by seeping water

Completed - Valve Flange

Corroded surface

Completed - Poscopower

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