2010 07 Notten NTT Consultancy UreaKnowHow.com Failure Urea Reactor external nitrate SCC

One main condition for atmospheric corrosion  or corrosion under insulation to take place is moisture. Moisture which penetrates the insulation may originate from:
• Rain water
• Vapour resulting from “breathing” 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 area’s)
• Stress Corrosion Cracking
– carbon steel:  NO3- – ions
– austenitic SS:  Cl- – ions
– copper alloys:  NH3

This Paper discusses the catastrophic failure of a high pressure urea reactor due to external nitrate stress corrosion cracking.

Share this on:

UreaKnowHow.com is an independent group of nitrogen fertilizer specialists with an impressive number of years experience in designing, maintaining and operating nitrogen fertilizer plants.

Solution Providers offer their solutions to improve our member’s plants performance.