Corrocoat USA were asked to apply a surface tolerant coating system to the structural steel on a pipe bridge, on site at a coal-fired power plant in Florida. The pipe bridge, spanned a 135 foot (41 meter) diameter thickener tank, which is used to clarify or separate the solids included in recycled gypsum. The solids are transported from the recycling tanks, which are upstream in the Flue Gas Desulphurization System. Once clarified, the gypsum is refined further and then sold to a neighbouring facility who use the gypsum to make drywall board, used in houses and commercial buildings.
The client hired a firm to perform an engineering inspection in the spring and were advised to replace the severely corroded steel members, and apply a suitable corrosion resistant coating to the new and remaining members. The structural steel members were corroded as a result of a reaction with the low pH vapours, that fume up from the tank beneath.
As this tank was integral to the power generation process, the project was completed during an outage. Corrocoat USA had only 2 weeks to complete the project, which included 4,700 square feet (432 square meters) of structural steel, many of which were small angles, channels and I-beams.
Working off scaffolding, the crew executed a surface tolerant specification that included pressure washing, spot preparation using angle grinders and needle guns. They then primed with Plasmet ZF; a surface tolerant two-pack epoxy coating compound incorporating a rust inhibitor and passivator, with MIO (micaceous iron oxides) and glass flake for increased protection. This was then over-coated with Corrothane AP1.
It took 12 men thirteen consecutive days, working long hours, to complete the project to the satisfaction of the customer. The team completed the project one day ahead of schedule, an impressive feat considering the intricacies/geometries of the project.