OVERVIEW: Exhaust stacks in a methane gas power plant are genuine workhorses. There’s no time for rest, and they need to be productive 24/7. Obviously, corrosion protection is a real challenge, but one that is critical to keeping exhaust stacks performing as efficiently as possible, but also in preventing power outages when maintenance is required.
INDUSTRY
ENVIRONMENT
Methane gas co-generation plant exhaust stack trials
SUBSTRATE
Mild Steel
CHALLENGE
Restoring these exhaust stacks to their former glory was no easy feat. The 15-year-old plant had started show signs of premature corrosion within four years of commissioning. The task to refurbish the giant exhaust pipes and manifolds was entrusted to Chemcote. Not only was spark-free surface preparation a strict requirement, the new protective coatings needed to be applied on a 105°C surface temperature, all while the plant remained online.
SOLUTION
The initial step involved mobilising site assets including plant maintenance personnel, conducting safety assessments, and securing required access.
Prior to any coating applications, the stacks needed to be mechanically cleaned using a wire bush. Two coats of Epo-chem™ RL 500PF, a surface and moisture tolerant zinc rich epoxy, were then applied.
SCOPE
Mobilize to site and work in with plant maintenance personnel to ensure all risks are assessed and reduced where possible
Obtain safe access and mechanically clean, using a wire brush only
Application of 2 coats of RL 500PF with a nominal DFT of 300µm
PRODUCTS
Epo-chem™ RL 500PF – Surface and moisture tolerant zinc rich epoxy
OUTCOME
Over the past five years, Chemcote have inspected the exhaust stacks, and no signs of corrosion or coating failure have been evident. The protective solution offered plant maintenance engineers the peace of mind that the stacks now had a life expectancy of more than 10 years before any signs of corrosion would be visible.
RELATED CASE STUDIES
Stern Tube Life Extension During Half-life Refit
Patrol boat in slipway for refit Protection against abrasive blasting damage Application of RB364 Tube internal lining complete Overview: The half-life refit of critical components
Air Receiver Restoration for Long-Term Durability
Pitting corrosion near shaft landing After first abrasive blasting After 2nd Abrasive blast holes were found requiring composite reinforcement Filling void in difficult to reach
High Performing Replacement for 316L SS
On inspection flange corrosion Deep pitting on forged section Application of 1st coat Ready to be put into service for 25+ years of life OVERVIEW: