Corrosion has long been the oil industry's nightmare. Now, thanks to new approaches and coatings, the difficulties are being solved.
by EonCoat*
According to a recent report by NACE (National Association of Corrosion Engineers) International, in the oil industry corrosion is the cause of more than 25% of failures. Repairing or replacing corroded pipes costs the industry more than $7 billion a year, according to NACE estimates. This figure can double if you count the loss of revenue and productivity, as well as the costs associated with cleaning up spills or leaks.
"Corrosion is a huge challenge for the industry, affecting everything from the outside of floating roof tanks, to the inside of tanks, to piping systems that go above and below ground level, specifically at those points where pipes go from elevated to below level," said Scott Justice, operations manager for the tank division of Bolin Enterprises Inc. (BEI), a contractor based in Casey, Illinois, which provides pipeline and tank maintenance services to the oil industry.
Although conventional methods of corrosion protection mainly rely on short-lived coatings, with physical adhesion to the surface of the substrate – such as tapes, elaborate three-component coating systems (zinc, epoxy and urethane), or cathodic protection – these methods are limited to trying to postpone the moment when the steel inevitably, it will rust.
Today, an increasing number of high-initiative oil industry maintenance professionals are turning to a new category of rugged chemical phosphate cements (CBPCs) that can stop corrosion, extend equipment life, and minimize the cost and downtime of production required to coat, repair or replace corroded equipment.
A new method of protection
"What caught my attention about EonCoat was its unique adhesive and chemical properties," said Justice, who visited The North Carolina company Wilson to observe its anti-corrosion testing laboratory, as well as its processes and procedures for CBPC coating.
"If the outer hard layer of this coating breaks or falls off, it continues to provide corrosion protection where traditional coatings stop. Even if the coating is old, beaten or dented, it still protects the surface. If the outer ceramic layer is removed, the chemical adhesion with the substrate continues to act to stop corrosion on the surface."
Unlike conventional polymer paint-based coatings, which sit on top of the substrate, the anticorrosive coating adheres through a chemical reaction to the substrate, and a slight oxidation of the surface actually enhances the reaction. This makes it impossible for corrosion-promoting components such as oxygen and moisture to be located behind the coating, as can happen with conventional paints. The corrosion barrier is covered by an all-ceramic layer, resistant to corrosion, fire, water, abrasion, chemicals and temperatures up to 1,000 °F (537 °C).
Although traditional polymeter coatings create a film that mechanically adheres to substrates that have previously gone through an intense preparation process, when drilled, moisture and oxygen move under the coating film from all sides of the perforation.
The film then traps moisture and heat, creating a "greenhouse effect", which favors corrosion and blistering. Conversely, when the same damage occurs on a ceramic-coated substrate, corrosion does not spread because the steel is basically alloyed. The oxides on its surface have been converted into an inert, electrochemically stable metal, unable to support oxidation.
Ceramic coatings are composed of two non-harmful ingredients, which do not interact until they are applied by a spray gun of various components, such as those usually used to apply polyurethane foam or polyurea coatings. Since the components are not mixed and do not come together before application, there is no need to use hazardous ingredients that produce VOCs, such as hazardous pollutants and odors. This means that work can be carried out in busy areas.
"The results of the corrosion tests performed on the tanks were impressive," Justice said. One of the corrosion tests commonly performed by the manufacturer of the CBPC product is one in which the ceramic coating remains for more than 10,000 hours without corrosion, after being subjected to an ASTM B117 salt spray test.
"If the coating works as well as we expect, it could help stop or minimize corrosion and extend the life of a number of oil assets," Justice added.
Unlike organic paints and coatings based on carbon polymers, which can promote corrosion, since they promote the growth of microbes, ceramic coatings such as CBPC are completely inorganic, so they are not favorable means for mold or bacteria.
"Because EonCoat is inorganic, it cannot support the growth of mold or bacteria," Justice added. "This could help control corrosion problems related to mold growth on the outer surfaces of water storage tanks or elevated tanks, specifically when using new oxygenated fuels."
Although not a widely discussed issue, the Achilles' heel of many conventional anti-corrosion coatings may lie in the fact that environmental conditions must have precise characteristics during application for specifications to be met.
"Many coatings fail due to changes in temperature, humidity, dew point and other atmospheric factors at the time of application," Justice said. "Because conditions change seasonally, throughout the year, it can be difficult to provide perfect conditions for coating application."
An advantage of the corrosion protection provided by ceramic coatings is that they can be applied on hot and cold surfaces, with temperatures from 40°F (4°C) to 150°F (65°C), humidity levels of 0-95%, except in direct rain conditions.
"Because ceramic coating leaves out of the equation changes in temperature, humidity and dew point during application, it can be reliably used in harsh environmental conditions, which could otherwise jeopardize the corrosion protection of traditional coatings," Justice concluded.
Reduced production disruption
Shane Bartko, director of TKO Specialty Surfaces, a contractor that maintains tanks, pipelines and structures, based in Calgary ( Alberta), has used ceramic coating for corrosion control in various projects in the oil industry, among others, storage and process tanks, torch tanks for refineries, roofs of sulfur plants in refineries, as well as a train and tower loading platform.
"To maintain the proper functioning of the anti-corrosion coating, it is desirable to use one that is resistant to high temperatures, abrasion, chemicals, UV sunlight and other environmental factors," Bartko said. "While EonCoat has strengths in these areas, it is equally important how quickly an oil facility can be restored. For comparison, it took us about four days with EonCoat, compared to about 10 to 12 days with other coatings."
The time saved in an anti-corrosion coating project with the ceramic coating comes from both the simplification of surface preparation and the acceleration of curing time. "With a traditional anti-corrosion coating, it is necessary to clean with abrasive to white metal to prepare the surface," Bartko said. "But with ceramic coating, it is usually only necessary to do a commercial grade abrasive cleaning 3, according to the international standard NACE."
Bartko explained that in coating projects that use conventional polymer-based paints, such as polyurethanes or epoxy resins, the curing time can be days or weeks, before the next layer of three coatings can be applied, depending on the product. Curing time is necessary to allow each layer to fully reach its properties, even if it feels dry to the touch.
On the contrary, an anti-corrosion coating can be achieved with the ceramic coating in a single layer, with almost no curing time needed. Computer operation can be resumed in as little as one hour.
"With the anti-corrosion ceramic coating, we can resume the operation of the facilities immediately after application, sometimes even after an hour," Bartko explained. "That level of speed in restoring production to an oil facility can mean potential savings of millions of dollars a day in equipment downtime.
It's worth using ceramic coating anywhere steel is used and corrosion can occur, from pipelines and processing tanks to storage tanks."
* You can contact the company at email [email protected]; or visit the website www.eoncoat.com
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