When a pair of sulfuric acid tanks at a Texas refinery showed signs of interior pitting, plant officials applied a 100 percent solids, high-build reinforced novolac epoxy coating from Tnemec to achieve a smooth, breach-free liner. “The high-build characteristics of Series 365 Tank Armor allowed them to fill the pitted surface with one coat,” according to Tnemec coating consultant Eddie Borne. “With this application, there was virtually no touch-up required.”
“The plant engineers had worked with other Tnemec, but not this specific coating,” Borne acknowledged. “They were looking for something that would be user-friendly and that would allow them to put the tanks back in service quickly. Series 365 self-cures so it can be walked on and spark-tested within a few hours of being applied. Its ability to tolerate early immersion saves both time and labor, while providing the steel substrate with a hard, tile-like finish.”
Prior to coating with Series 365, both tank interiors were prepared in accordance with SSPC-SP5/NACE No. 1/ISO SA 3.0 White Metal Blast Cleaning, with a minimum angular anchor profile of 3.0 to 4.0 mils. The two-component coating was spray-applied using a Graco Xtreme plural component proportioning pump at 40 mils dry film thickness (DFT).
“Since Series 365 is 100 percent solids, it doesn’t contain any solvents like many other liners do,” Borne noted. “So when applicators are working in a confined area like the interior of a tank, they’re not breathing solvent fumes and the potential for combustion resulting from an accidental spark is greatly reduced.”
Applicators were especially pleased with the ability of Series 365 to create a monolithic liner free of voids which have the potential to allow sulfuric acids or other reagent chemicals to attack and corrode the steel interior of the tanks. “They said the liner looked gorgeous and was breach-free,” Borne added. “When they conducted the high-voltage spark test on the liner, the tester passed over the surface without creating any sparks. Usually, if there’s the tiniest hole in the liner, the voltage tester will spark in that spot, which means it has to be touched up, requiring extra time and labor.”
Tnemec coatings including Series 30 Spra-Saf EN, Series 66 Hi-Build Epoxoline, Series 90-97 Tneme-Zinc and Series 1074 Endura-Shield II were also utilized on the exterior of the refinery’s steel storage tanks.