2010 07 Notten NTT Consultancy UreaKnowHow.com Failure Urea Reactor external nitrate SCC
One main condition for atmospheric corrosionĀ or corrosion under insulation to take place is moisture. Moisture which penetrates the insulation may originate from:
⢠Rain water
⢠Vapour resulting from ābreathingā due to cyclic temperature changes, followed by dew formation
⢠Increased water exposure resulting from:
– nearby cooling towers
– water-jetting of heat exchangers
– fire-fighting drills
– sprinkler installations
– leaking trace lines
Atmospheric corrosion or corrosion under insulation can have the following forms:
⢠Overall corrosion (crater-like attack at critical areaās)
⢠Stress Corrosion Cracking
– carbon steel:Ā Ā NO3- – ions
– austenitic SS:Ā Ā Cl- – ions
– copper alloys:Ā Ā NH3
This Paper discusses the catastrophic failure of a high pressure urea reactor due to external nitrate stress corrosion cracking.
2010 07 Notten NTT Consultancy UreaKnowHow.com Failure Urea Reactor external nit
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