Gerald O. Wilson reveals how self-healing coatings can contribute to the decarbonisation of asset maintenance
BP has recently announced a strategic shift that will see it move towards becoming a net zero company by 2050. For BP and the oil and gas industry in general, achieving net zero will require aggressively decreasing carbon emissions across all operations. One significant source of emissions that is often overlooked is asset protection and maintenance operations, which often include painting activities. Painting activities contribute to emissions in the form of volatile organic compounds (VOCs) released into the environment during painting, and fuels consumed during surface preparation, and paint or coating application, as well as during materials manufacturing. It stands to reason then that the less frequently assets are painted, the lower their carbon emission contribution over their lifetime.
How does self-healing coating work?
Autonomic Materials (AMI) is an expert in the development of protective coating systems incorporating self-healing functionality. Self-healing coatings are a class of smart coatings that respond to damage by autonomically releasing a healing agent from embedded microcapsules into the site of damage. Once in the site of damage, the healing agent – a blend of polymer precursors, diluents, adhesion promoters and corrosion inhibitors – polymerises, restoring the coating’s protective functionality. By arresting damage in a coating early, self-healing functionality keeps the coating on the substrate for a longer period of time, thereby delaying the need for maintenance. Longer maintenance cycles translate to lower carbon emissions, lower maintenance costs and less downtime over the lifetime of the asset.
AMI’s self-healing coatings protecting oil and gas assets
AMI’s self-healing functionality has been demonstrated in multiple coating types, including solvent-borne epoxies, zinc-rich primers, waterborne epoxies and epoxy powder coatings to name a few examples routinely used for protecting oil and gas assets. Fig. 1 shows a comparison between two versions of a powder coating system. Both coating systems were evaluated on iron phosphate pretreated steel coupons and were coated with epoxy primers and polyester topcoats. The self-healing coating system incorporated AMI’s Amparmor 2000 series in the primer, while the topcoats were identical. Both coated coupons were damaged by scribing and exposed to a salt fog. The coupons were removed from the salt fog in 250 hour increments and the extent of corrosion creep and loss of coating adhesion was evaluated by scraping the coating around the scribe. Although the control exhibited rapid adhesion loss after 1,000 hours of salt fog exposure, no adhesion loss was observed for the system incorporating Amparmor 2000 until after 3,000 hours of exposure, after which the adhesion loss occurred at a substantially slower rate. At the completion of the test, a four-fold life extension was observed relative to the control (Fig. 2).
The return on investment in self-healing coating systems that result in longer maintenance cycles for coated assets maintained in an offshore environment has been previously analysed by AMI. The results of this analysis showed that cost savings of as much as 32.7% could be realised by simply increasing the service life of a coating system from 12 years to 15 years. Since VOCs are typically released mostly when coatings are applied during painting activities, similar decreases in VOCs are expected. And although good estimates for the amount of emissions associated with all the other asset protection/maintenance operations activities are not readily available, extrapolations from other similar assets such as bridges suggest that the decrease in carbon emissions due to these activities could be substantially greater than those contributed by VOCs.
Gerlad O. Wilson is president and CEO of AMI