The Mixed Bed Regenerator Vessel forms part of the Power Station’s water treatment plant, backwashing, rinsing and injecting resins with sulphuric acid and caustic soda. A recent inspection revealed the internal rubber lining to be significantly blistered with some patches degraded through to substrate.
Following the removal of lateral supports and internal pipework, chemical resistant lining Ceilcote 242 Flakeline by International Paints was used for the vessel refurbishment. Ceilcote 242 Flakeline is a flake filled vinyl ester coating with excellent resistance to organic and inorganic acid solutions and many aliphatic solvents. It has a designed lifetime of ten years. The coating system comprised of primer and four coats roller applied.
Lateral supports and pipework were inspected and cleaned for blockages and recoated externally. This process took place offsite at CSC Services premises, to minimise disruption at the Power Station.
To ensure the substrate was prepared correctly, Ultra High Pressure Water Jetting was used at 36000psi. This was followed by grit blasting to Standard Sa3. The difference between the two processes can be seen in the photograph, with the bottom section grit blasted.
On completion of the work dry film testing and spark testing were undertaken and showed 100% coating coverage had been achieved within specification. On signing off the work Alan Smith, Project Engineer from Dungeness B Power Station said:
“This project was a collaborative effort throughout, with CSC providing advice to inform the specification of the coating material, working closely with both Investment Delivery and the Technical Advice Group. The quality of workmanship and application of the coating have been noted by others and positively regarded.”
Images from the work undertaken are shown below: