Anion Pressure Vessel.

Anion pressure vessels form part of a power station's water demineralisation system and contain ion-exchange resin used to remove negatively charged dissolved contaminants, including chlorides, sulphates, nitrates, silica and alkalinity. Typically operating downstream of a cation vessel, the treated water passes through the anion resin before being supplied as high-purity boiler feedwater or further polished within the treatment system.

These vessels must safely withstand operating pressure, repeated regeneration cycles and exposure to caustic regeneration chemicals while maintaining even water distribution through the resin bed to protect boilers, turbines and associated steam-cycle equipment from scaling, corrosion and contamination.

MEA's scope of works included the complete design, fabrication, testing and site installation of a new anion pressure vessel for Callide Power Station. As a pressure-retaining vessel intended for chemical service, the project required approved welding procedures, qualified pressure-vessel welders and stringent fabrication quality controls throughout manufacture.

Following completion of the vessel shell, heads, nozzles and associated attachments, the vessel underwent the required inspections and pressure testing. The complete internal surface was then rubber lined to protect the steelwork from the corrosive process environment, and an alkali-resistant grout was installed within the upper spherical head to provide additional chemical protection and create a durable internal lining in this area.

Once fabrication, testing and internal lining were complete, MEA applied the final external protective coating system and prepared the vessel for transport. MEA then mobilised to Callide Power Station and completed the full site installation, including positioning, mechanical installation and final integration of the vessel into the plant.