Amine Corrosion - Basic
General:
General and/or localized corrosion that occurs on carbon steel in amine process as a result of dissolved acid gases (CO2 & H2S), amine degradation products, heat stable amine salts and oher contaminants. Amine (e.g. MDE, MEA, DEA, DIPA) is a catalyst solution used to absorb CO2 and H2S from natural gas stream in a natural gas processing facilities.


Apprearance:
Uniform thinning or localized corrosion on carbon steel or low alloy steels.




Photo 1: Amine corrosion on carbon steel tubes on lean-fat amine heat exchanger



Photo 2: Amine corrosion on a pipe submerged in amine storage tank



Photo 3: Amine corrosion on tank wall storing amine.


Main factors affecting severity of corrosion:
(1) Concentration of amine:
a. Pure amine is non-corrosive (due to high pH)
b. Rich amine is more corrosive due to higher acid-gas loading
c. Lean amine is relatively less corrosive due to lower acid-gas loading
(2) Temperature (>104oC),
(3) Acid-gas flashing,
(4) Protective scales (FeCO3, FeS) degradation.


Preventions / Mitigations:
(1) Minimize effect of acid-gas flashing – by proper operation controll
(2) Corrosion resistant materials – e.g. SS cladding
(3) Inert-gas blanketing i.e. prevent oxygen ingress



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Labels: Acid Gas, Amine, Amine Corrosion, Corrosion, LNG, Natural Gas, Sulfinol

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