Why after years & years of service we have started experience amine stress corrosion cracking in our piping?
And where else should we be looking for similar damage to occur?
Should inspection go beyond piping to pressure containments including vessels, exchangers?
Amine Stress Corrosion Cracking
Re: Amine Stress Corrosion Cracking
Yes. If you have confirmed or strongly suspect Amine Stress Corrosion Cracking (ASCC) in piping after many years of trouble-free operation, the investigation should extend beyond the affected line. ASCC is often a plant-wide degradation mechanism rather than an isolated piping problem.
Re: Amine Stress Corrosion Cracking
Yes. Once ASCC is confirmed, the damage mechanism review should encompass the entire amine circuit, including:
All carbon steel piping in lean and rich amine service.
Pressure vessels (absorbers, regenerators, flash drums, accumulators).
Heat exchangers handling amine.
Pump and valve welds.
Small-bore connections and instrument nozzles.
Recent modifications and tie-ins.
High-stress supports, anchors, and expansion restraint locations.
The inspection scope should be risk-based, prioritizing components with:
Higher operating temperatures.
Higher H2S or CO2 loading.
Welded construction.
High residual or operational stresses.
Older equipment and a history of repairs or modifications.
All carbon steel piping in lean and rich amine service.
Pressure vessels (absorbers, regenerators, flash drums, accumulators).
Heat exchangers handling amine.
Pump and valve welds.
Small-bore connections and instrument nozzles.
Recent modifications and tie-ins.
High-stress supports, anchors, and expansion restraint locations.
The inspection scope should be risk-based, prioritizing components with:
Higher operating temperatures.
Higher H2S or CO2 loading.
Welded construction.
High residual or operational stresses.
Older equipment and a history of repairs or modifications.
Re: Amine Stress Corrosion Cracking
A comprehensive root-cause investigation should commence integrating:
Solvent health assessment (HSS, degradation products, contaminants).
Review of historical operating conditions and changes.
Material and fabrication records, including PWHT history.
Stress review (thermal, mechanical, vibration, and support changes).
Fitness-for-service evaluation of detected cracks (e.g., following API 579/ASME FFS-1 where applicable).
Update the RBI program to include ASCC as an active damage mechanism and revise inspection intervals and techniques accordingly.
Solvent health assessment (HSS, degradation products, contaminants).
Review of historical operating conditions and changes.
Material and fabrication records, including PWHT history.
Stress review (thermal, mechanical, vibration, and support changes).
Fitness-for-service evaluation of detected cracks (e.g., following API 579/ASME FFS-1 where applicable).
Update the RBI program to include ASCC as an active damage mechanism and revise inspection intervals and techniques accordingly.
Re: Amine Stress Corrosion Cracking
Have you identified the issue of all this cracking happening now?
The issue would have been non-PWHT carbon steel welds or in highly cold worked parts like fittings.
It is recommended that there should be an inspection plan developed to cover the whole piping circuit to identify any similar issue which might not have resulted in a leak.
The issue would have been non-PWHT carbon steel welds or in highly cold worked parts like fittings.
It is recommended that there should be an inspection plan developed to cover the whole piping circuit to identify any similar issue which might not have resulted in a leak.