OVERVIEW: The tube sheets of this chiller suffered severe corrosion due to a galvanic reaction between dissimilar metals, along with extensive pitting corrosion on the sealing faces. To address this, a 72-hour shutdown period was utilised, during which the tube internals were safeguarded from abrasive blasting damage using specially designed plastic caps.
INDUSTRY
ENVIRONMENT
60-80°C, re-circulated sea water
SUBSTRATE
Mild Steel water boxes & bronze tube sheets
CHALLENGE
Tube sheets of this chiller were severely corroded due to a galvanic reaction between dissimilar metals. A 72 hour shutdown period was utilised to complete the work. The tube internals had to be protected from abrasive blasting damage. There was also severe pitting corrosion on sealing faces.
SOLUTION
Tube internals were protected by inserting specially designed plastic caps.
The entire chiller face was abrasive blasted to ensure surface is clean and free of contamination. RB 300 was applied to tube-sheet face, followed by post machine sealing faces to ensure division plates mate, preventing interference and by-passing. Caps were removed. Chemcote also supplied nylon inserts to prevent tube end corrosion & cavitation.
PRODUCTS
Chem-tect™ RB 300 Series
OUTCOME
This client has become one of our regular customers. Chemcote has now conducted numerous jobs for this client over the past years, including multiple heat exchanger units. The photo to the left was taken during a 4 year inspection of another chiller unit coated with the same coating and showed no signs of deterioration.
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