OVERVIEW: 10 year old carbon steel Intercooler Vessel was exposed to high pressure steam, exceeding 150°C. The vessel was experiencing severe corrosion and metal loss. We had a short window to machine rebates in all flange faces to allow coating to be applied from the internals out onto the flange face.
INDUSTRY
ENVIRONMENT
High Pressure Steam, exceeding 150°C
SUBSTRATE
10 year old carbon steel Intercooler Vessel
CHALLENGE
The vessel was experiencing severe corrosion and metal loss. We had a short window to machine rebates in all flange faces to allow coating to be applied from the internals out onto the flange face.
SOLUTION
On close inspection, deep pitting was found in a number of areas, particularly in the bottom part of the vessel. Weld repairs would have delayed the project so Chemcote recommended pit-filling to be carried out to reduce down time and the use of composite fibres to increase strength. RF 300 series was recommended as the coating requires low maintenance and ease of repair-ability. It will also provide 20 years of corrosion protection.
SCOPE
Abrasive blast to AS 1627.4 2005 75
Reduce metallic salts using 90°C high pressure water
Re-abrasive blast to above standard
Application of 1200µm of RF 332: A glass flake filled high temperature vinyl ester designed to provide long life corrosion protection
All internal and external flange faces are coated to ensure full protection
High Voltage spark test @ 8kV DC & rectify defects
Application of RL 500PF in two coat and RC 500GTC
OUTCOME
The intercooler vessel was inspected 4 years and again 8 years after original application and found in excellent condition. There were no signs of corrosion or coating breakdown. Some mechanical damage to the internal lining required repairs where the tube bundle installation/inspection impacted on the lining integrity on the guides.
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