PLANT MANAGEMENT
underneath the primer, causing further corrosion. Most primers on the market go only as far as encapsulating the iron oxide – which is not 100% effective in preventing further rust from occurring.” Another reason that chemical facilities
are prone to corrosion when using typical primers is that a high level of surface preparation is required because most rust primers on the market are sensitive to chlorides. “Even a minute amount of chloride on the steel can cause coating system failure,” says Lawrence. “Tis is why leading coating manufacturers demand extreme levels of surface cleaning (sandblasting) and removal of chlorides to a level of 5 mcg/m2
, which is nearly
impossible to achieve. Even when sandblasting is used for surface preparation, flash rusting will still occur.” In response, the search for more enduring corrosion protection at petrochemical facilities has involved the development of long-lasting primers that correct the deficiencies of traditional methods.
LASTING PROTECTION NanoRustX (NRX) NanoPrime, for example, works by chemically reacting with iron and iron oxide (rust) to form iron phosphate and creates a nano bond with both metallic and painted surfaces. Te chemically bonded layer is insoluble and extremely corrosion resistant. Tis “bonding” process also provides superior adhesion and flexibility and stops under-film corrosion that occurs when conventional coatings are damaged. Te non-toxic, ultra-low VOC primer contains nano-polymers for added strength and durability and has been tested to successfully coat surfaces from rust-free to up to 700 microns of rust. Te elasticity of the advanced primer makes it very durable in temperature variations from -67°C to 200°C. Because the advanced primer chemically
reacts with galvanised steel surface, no surface preparation is required other than a water wash. Te water-based acrylic polymer is not sensitive to chlorides or rust and can actually neutralise them. Unlike initial generations of rust converting primers, the primer performs equally well on clean, partially corroded and heavily rusted surfaces. Typically, a power wash (240 bar/3,500 psi) is all that is needed before applying to steel (clean or corroded), galvanised steel or aluminium to remove
loose paint, dirt and grease. Te primer can be applied to a corroded surface by hand brush, roller or airless spray gun on the substrate. After the application of the primer, a single coat of a low VOC top coat will complete the job.
CASE STUDY
When a chemical plant in the Newark, New Jersey area had a number of roof exhausts with severe corrosion, Marzano, who had sought a lasting corrosion solution for his customers, applied a coat of NRX NanoPrime with no topcoat to a 50ft high roof stack as a trial. “Te roof exhausts were so rusty the chemical company was ready to replace them, which would have cost about US$7,000 to 9,000,” he explains. “However, about five years later there still is no visible rust on the roof exhausts. Te success of the trial demonstrated the primer’s effectiveness against chemical plant corrosion, so we have applied it many times since then on everything from roofs, exhaust fans and exhaust stacks to tanks for carbon monoxide and sulphuric acid.” In one of Marzano’s recent applications,
his Maxim Contracting work crew coated four outdoor and three indoor chemical tanks, ranging from 1,500-10,000 gallons, including a liquid nitrogen tank and a 2,000-gallon CO2
tank. Using a spackle
knife and palm sander to remove existing loose flaking paint and rust, and a water wash with nearby hose, the surfaces were readied for applying the primer. Te system included two coatings of primer applied by
NanoPrime salt spray test panel after 7,775 hours
roller, followed by one application of the customer supplied water-based, industrial epoxy topcoat. “With NRX NanoPrime, less surface
preparation is required compared to other primers,” says Marzano. “Also, it can dry in 30 minutes to touch and takes about two hours to apply a second coat, depending on temperature, which is much faster than typical primer and paint. So, we finished the job in a few days rather than a week, which helped to reduce potential downtime for the facility. “But the bottom line is that the primer prevents corrosion and really lasts,” concludes Marzano.
After a second coat of NanoPrime
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