OVERVIEW: The 304 stainless steel ammonia absorber and circulation tank experience temperatures of up to 100°C and an aggressive Chemical environment.
The prevention of stress corrosion pitting was achieved in the heat affected areas by applying corrosion protection on the entire internal surface.
INDUSTRY
ENVIRONMENT
Normal operating temperature is 60-70°C. Excursions up to 100°C are common.
• Wet ammonia gas
• Diluted sulphuric acid (up to about 20%)
• Ammonium sulphate
• Naphthalene
• Benzene
• Aromatic and aliphatic hydrocarbons
• Hydrogen sulphide
• Hydrogen cyanide
SUBSTRATE
304 Stainless Steel – Ammonia absorber and circulation tank
CHALLENGE
Prevent Stress Corrosion Pitting in the heat effected areas, these are generally found either side at the toe of the weld. Apply corrosion protection on the entire internal surfaces within a 72 hours outage
SOLUTION
Abrasive blast to Chemcote’s Specifications and 3 coats of Chem-tect™ RF 300 Series
SCOPE
Recommend the entire internal surfaces are treated
Mobilise on site
Set up of dust containment only
Set up of De-humidification equipment
Abrasive blast to Chemcote Standards
Application of a Chem-tect™ RF 300 in 3 coats including strip coat all difficult to reach areas
De-mobilise from site
PRODUCTS
Chem-tect™ RF 364 – vinyl ester / acrylic co-polymer enhanced with flaked glass; very suitable for immersed environments where superior resistance to chemical attack is required
OUTCOME
The best outcome the asset owner has obtained after years of trials using various epoxies and fibreglass linings. The combined large anchor profile achieved while abrasive blasting and excellent permeation resistance of the glass flake filler has proven itself again.
RELATED CASE STUDIES
22 year old pipes coated with glass flake vinyl ester
Internal lining in excellent condition Abrasive blast externals Recoating of externals Recoating of externals in basement OVERVIEW: The pipes were originally coated internally using
Premature Failure of 316L Stainless Steel Pipes
Severe pitting after 2 months in service After abrasive blasting Damaged internals rebuilt and coated Externally applied caution OVERVIEW: New 316L pipe failed after
Corrosion protection ensures a long life for a new 98% Sulphuric Acid Bund
Newly constructed bund Primer application Application of final coat Job completed OVERVIEW: Chemcote was contracted to apply acid protection to a newly constructed delivery