Composites Today

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Application of composites wrap system to combat tank corrosion under extreme conditions

Figure. Composite wrap system curbs corrosion under insulation at nickel mine

Figure. Stainless steel feed tank repaired and protected with Belzona SuperWrap II

Rezitech, the authorised distributor for Belzona composites wrap system provided a full turnkey solution to combat corrosion under insulation on an ammonium sulphate feed tank at a major global blue-chip nickel, mine in Australia. Within the space of 24 hours, the 9.5 metre (31.2 ft) diameter tank (with a height of 2 metres (6.6 ft) from ground level) was repaired and protected against future corrosion with the industrial composite wrap system, Belzona SuperWrap II.

The stainless-steel feed tank was suffering from corrosion under insulation and chloride induced stress corrosion cracking. They required a solution that would not only restore the integrity on the substrate, but also protect the asset against future corrosion damage. Not only this, but as the tank operates at elevated temperatures of approximately 70°C (158°F) and processes highly corrosive medium, the repair solution would need to be able to withstand these harsh conditions.

Belzona the UK headquartered company, specialising in the design and manufacture of repair composite materials and protective coatings for machinery, equipment, buildings and structures, offers an extensive range of engineering problems and repair situations.  Rezitech is the sole Australian Distributor for Belzona.

Having worked with Rezitech over the course of five years, the customer had complete confidence in the range of Belzona metal epoxy repair composites and industrial repair coatings the Distributorship offers. As such, they decided to contact them again for their advice and system recommendation.  

Following an inspection by Rezitech engineers specified the composite wrap system, Belzona SuperWrap II. This composite wrap system is comprised of a fluid-grade resin system, a bespoke hybrid reinforcement sheet, based on glass fibre and carbon fibre, as well as a release film to compact and consolidate the application. The system is specially formulated to restore the strength of holed, weakened, and corroded pipe and tank walls, making it the ideal solution for protecting the asset against corrosion under insulation for the long term. In addition, thanks to the cold-curing properties of the composite wrap system, this mitigates the need for hot work, making it a reliable alternative to welding.

Application Procedure

Firstly, all traces of oil and grease contamination were removed using a suitable Rezitech Degreaser. Following this, the surfaces were grit-blasted to provide a surface cleanliness compliant with ISO 8501-1 SA 2½ (ASNZ 1627.4 class 2.5) with a minimum 75 µm (3 mil) rough angular profile.

Once the surface was prepared, the Belzona 9381 reinforcement sheet was measured out and then wetted out with the Belzona resin system. The resin was then systematically applied to the areas to be repaired. Following this, the Belzona reinforcement sheets were then applied to the tank in three layers. The compression film was then added to the top of the application area. Next, using a roller, the Belzona SuperWrap II composite wrap system was then spread, rolled and compressed to the surface of the tank. The system was then left to cure for approximately eight hours.

Bypass the Need for Replacement with Polymeric Technology

By investing in the Belzona composite wrap solution, this enabled the customer to successfully bypass the need to replace the corroded asset, and instead prolong the lifespan of the asset for years to come. Thus, this enabled the customer to make significant savings in both time and money. In addition, given the important role EVs play in reducing global carbon emissions, (Nickel sulphate is an essential ingredient in the lithium-ion batteries that drive electric vehicles (EVs.), it could be argued that polymeric technology also plays a fundamental role in supporting this transition by safeguarding the integrity of key assets within this industry.