CHINESE DISTRIBUTOR SUPPLIES BELZONA SUPERWRAP II FOR RISER REPAIR AND PROTECTION
Nanjing Chenhui Mechanical & Electrical Engineering Co. Ltd., a Belzona distributor in the Chinese province of Jiangsu, recently came to the aid of an operator of an offshore platform located off the coast of mainland China that was experiencing external pitting corrosion on several of their risers. A damaged riser can cause significant downtime to a platform resulting in financial losses and possible pollution of the immediate environment; therefore, it is imperative to ensure their integrity.
An offshore riser is a conduit or collection of conduits used for the safe transportation of material (primarily fluids and gases) between the seafloor and the host platform. These fluids may travel from the seabed to the platform or from the platform to the seabed.
Due to the working environment, offshore risers are often susceptible to internal erosion and external corrosion and are often operating under high temperatures and pressures.
Nanjing Chenhui had previously worked with the customer in 2017 on a Belzona SuperWrap II application for the in-situ repair of 93 nozzles on six pressure vessels. By choosing SuperWrap II the customer was able to avoid any potential hot work or downtime in production. The completed nozzle repairs were inspected and certified by testing, inspection, and certification company Bureau Veritas (BV).
Such was the success of this earlier application that the customer invited Nanjing Chenhui to discuss the possibility of using SuperWrap II on their damaged risers. After several meetings and onshore evaluation testing, it was agreed that SuperWrap II was the optimal solution to their problem.
Belzona SuperWrap II was designed and engineered for pipe wrap and patch repairs, as an alternative to replacing defective metallic substrates, whilst providing superior strength, corrosion, and chemical resistance.
The system is available in various polymers making it suitable for applications across a wide range of climate conditions as well as having service capabilities up to temperatures of 150°C and pressures up to 200 Bar. Belzona SuperWrap II has been certified by several certification bodies such as the American Bureau of Shipping (ABS).
To comply with the ASME PCC 2 standard, the SuperWrap II application can only be carried out by Belzona certified applicators and requires a Belzona certified supervisor on-site for the project duration. The risers were in a Hot Work Restricted Area that does not allow for conventional dry blasting; therefore, Vapour Abrasive Blasting was chosen given its suitability for Zone 1 Explosive Atmospheres.
The risers were blasted to achieve Sa 2.5 cleanliness and a minimum depth profile of 75μm. Following the completion of vapour blasting the risers were cleaned and degreased with Belzona 9111. A rebuilding grade of Belzona was used to restore the surface profile of the risers in readiness for the wrapping. Throughout each stage of the preparation and application, strict quality controls were observed to ensure the application conditions were compliant.
The Belzona SuperWrap II System was installed in accordance with the design output for each of the risers, averaging a 24mm thickness wrap over a length of just under 1 meter. Belzona 1982 was chosen due to its long working life that allows applications in large volumes and at relatively high ambient temperatures.
Representatives from Bureau Veritas (BV) inspected all aspects of the application including the design of the repair, application, supervision and MQT and duly certified the application for this project.
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