After Hurricane Hugo destroyed the water cooling tower at the Williams Station Power Plant in June of 1989, engineers with South Carolina Electric & Gas (SCE&G) needed a high-performing coating system to protect their new replacement unit from corrosion. “They wanted to get the plant up and running, so this project was on a fast track,” recalled Dan Anderson, Tnemec coating consultant. “At the same time, they needed a coating system that would last as long as possible because you have to shut the entire plant down every time you recoat a cooling tower.”
Approximately 400 gallons of coatings were used on the water tower and connecting pipes, which were prepared by abrasive blast cleaning according to SSPC-SP10. Three coats of a polyamide epoxy, Series 66 Hi-Build Epoxoline, were applied to the large pipe interior at 4.0 to 6.0 mils DFT per coat. The piping’s exterior received two coats of the epoxy and a finish coat of an aliphatic acrylic polyurethane, Series 73 Endura-Shield, which is highly resistant to abrasion, wet conditions and exterior weathering. “All of the coatings were spray-applied at the jobsite because of the tight deadline,” Anderson noted.
More than 17 years later, the cooling tower’s coating system continues to provide corrosion protection, according to Anderson. Several other coating projects have followed, including a major job involving a selective catalytic reduction (SCR) unit designed to reduce air pollution at Williams Station, which is the second-largest fossil fuel plant in SCE&G’s system. That project used a zincrich polyurethane primer, Series 90-97 Tneme-Zinc, applied at 2.5 to 3.5 mils, followed by a finish coat of Series 73 Endura-Shield at 4.0 to 6.0 mils. “Those coatings were all spray- applied in the shop, then touched up in the field,” Anderson said. “About 4,000 gallons of coating were used for that project, which turned out great.”
“We know the power industry, which is why South Carolina Electric & Gas has used our coatings for more than 20 years,” Anderson added. “All their plants are using our coatings and it’s pretty amazing that during those 20 years we’ve never had a failure.”