The Incident:
A stainless steel nozzle on the top of a urea reactor is heated with carbon steel tracing. As the plant location is close to marine atmosphere, chlorides can accumulate at those locations were carbon steel and stainless steel touches each other leading to Chloride-Stress corrosion cracking of the SS nozzle.
The Consequences:
Risk of leak of a high pressure vessel
The Causes:
The combination of marine atmosphere, CS-SS touching each-other and moisture
The Lessons Learned:
- Assure proper insulation
- Install a cabine on top of reactor to protect against moisture and marine atmosphere
- Properly install tracing with spacers
- Apply SS tracing
- Apply coating on stainless steel when plant is located in marine atmosphere
by mark.brouwer » Thu Nov 16, 2017 1:17 pm