Offshore staff
RALEIGH, North Carolina – The Oil & Gas Technology Centre (OGTC) in Aberdeen, UK is conducting trials of an anti-corrosion coating developed by EonCoat on two North Sea platforms.
Conditions in the North Sea – a sometimes constant corrosive onslaught of waves and salt spray – can exceed the endurance capabilities of traditional coatings.
After extensive research, OGTC identified EonCoat’s spray-applied inorganic coating as a potential method of delivering long-term protection for offshore installations, thereby lessening the frequency of visits by land-based maintenance crews.
The anti-corrosive coating is described as a new category of tough, Chemically Bonded Phosphate Ceramics (CBPCs) that is said to stop corrosion and to be easier to apply.
OGTC worked with EonCoat’s UK distributor and applicator, SPi Performance Coatings, on two trial programs. SPi applied EonCoat to Total E&P’s Elgin ‘A’ wellhead platform and Nexen’s Buzzard platform, both in the UK central North Sea.
SPi applicators flew into Elgin ‘A’ last December, applying the coating to areas of the platform’s lower deck that were suffering from severe corrosion, with a topcoat added for aesthetic purposes.
Meuhlhan had undertaken surface preparation for the trial. In the trial area, the existing coating system was completely removed from structural steel tubulars and flat plate. The structure was then power washed and degreased to remove contaminants, with all tubulars blasted to SA2.5, and flat plate mechanically prepped to ST3.
While rust rashing was visible on areas prior to spray application of the anti-corrosion coating, this was deemed acceptable as the coating can be applied to a damp substrate with rust rashing/flash rusting, and high salt levels are said not to degrade the coating, which reduces surface preparation requirements.
According to EnCoat, the coating can cure in a single coat 15 minutes after application, unlike traditional coatings, which require extensive drying time between coats.
EonCoat is also said to chemically bond with bare substrate surfaces, providing an iron magnesium phosphate layer that prevents steel corrosion. This process provides a very thin layer (about 2 microns) of permanent protection.
A second layer – a tough ceramic outer shell – provides further protection, also serving as a reservoir to re-phosphate the steel if needed. This ensures the alloy layer remains intact, EnCoat said, allowing it to ‘self heal’ should it be breached by mechanical damage.
During the trial at Elgin ‘A’, testing has been performed via cross cuts roughly 6-8-in. long down to the substrate to provide evidence of the coating’s self-healing properties.
SPi applicators next headed to the Buzzard platform this June. After Stork had performed fabric maintenance and surface preparation, the SPi team applied the anti-corrosion coating to platform areas suffering from severe corrosion.
Results so far are reportedly promising, EnCoat said.
08/17/2018
