Materials Performance Supplements

Corrosion Prevention and Control for Tanks 2017

Materials Performance is the world's most widely circulated magazine dedicated to corrosion prevention and control. MP provides information about the latest corrosion control technologies and practical applications for every industry and environment.

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16 MAY 2017 MATERIALS PERFORMANCE TANK CORROSION CONTROL SUPPLEMENT TO MP Tnemec Company, Inc. Preventative Maintenance Can Keep Petroleum Tanks in Service The bottom plates of petroleum aboveground storage tanks are especially susceptible to corrosion attack because of wear and tear from floating roof legs, floor flexing, or changes in the materi- als being stored. Taking a tank out of service to replace its flooring is expensive and time consuming, which is why some petroleum facilities are initiating preventive maintenance programs that include the use of long-lasting, high-solids, thick film epoxy liners. "Replacing a floor is about four times the cost of applying a pro- tective liner," according to Chris Ard, Industrial Market Manager, who has visited several projects where a tank bottom was found pit- ted and in need of replacement. "These tanks do not have enough steel thickness to get through the next inspection cycle," Ard noted. One ground storage tank in the Port of Shreveport-Bossier had this very issue. After a new bottom was installed and the lining was applied, the decision was made to reline the facility 's remaining tanks under a preventive maintenance program designed to reduce their life cycle costs. "To lose a tank for two months because you have to replace the tank bottom is significant, whereas you can line the same tank in a week or two," added Ard. Ranging in size from 15,000 barrels to 100,000 barrels, the refinery 's tanks were coated with Tnemec's Tank Armor, a fiber- reinforced, self-priming 100% solids epoxy lining. The lining is spray- applied at 30 mils dry film thickness (DFT), then tested for hardness and holidays. Local Tnemec coating consultant Brandon Lomasney made the coating recommendations. "With a Tank Armor lining, priming isn't necessary," explained Lomasney. "But many tank applicators will apply a holding primer, if desired and/or specified, and stripe-coat welds, bolts, and other potential problem areas." Interior testing was performed in accordance with the American Petroleum Institute (API) 652 Linings of Aboveground Petroleum Storage Tank Bottoms, which describes the procedures for achieving effective corrosion control in existing and new storage tanks in hydrocarbon service. The exterior roofs and shells of each tank were also evaluated as part of the preventive maintenance program, stated Lomasney. "The roofs are exposed to direct sunlight, moisture, and coastal condi- tions: a very corrosive environment." Lomasney helped evaluate the existing coatings on the exterior shell of each tank for adhesion, film erosion, and percentage of rust- ing to see if they were in good enough condition to be overcoated. "In the end, our recommendation was to overcoat tank walls and blast and coat the roofs." Tnemec's advanced technology acrylic polymer, Series 30 Spra- Saf EN, was specified for use on the roofs and exterior tank walls. 6800 Corporate Dr. Kansas City, MO 64120 Tel: 1 800-TNEMEC1 Web site: www.tnemec.com Series 30 is a direct-to-metal, corrosion-inhibiting coating with "dry- fall" capabilities, built to reduce the potential for overspray problems on buildings and surrounding property. Chris Ard noted the success of Series 30 around the country. "We've seen Series 30 applied to structural steel, water tanks, pipes and ground storage tanks, and can be used on a wide range of sub- strates over aged coatings." "Aside from Series 30, Tnemec offers a wide variety of industrial coatings depending on exposure," added Ard. "Our Tank Armor lin- ings and our exterior coating technologies continue to evolve and help our customers protect their investments."

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