This month we are looking back to a paper from Mike Sheilan, Amine Experts Inc. One of our Best Paper Award Winners, presented during our Annual Conference 2025.

"Iron Sulphide - Friend or Foe Revisited"

Twenty years ago, Amine Experts published a seminal paper on H2S corrosion in amine systems, titled “Iron Sulphide – Friend or Foe”. The paper described the various forms of iron sulphide formed from the reaction between H2S and steel and how knowledge of these corrosive by products can provide a clue as to the formation mechanism, the severity of the potential corrosive environment and the degree to which the corrosion will affect operation of an amine unit.

Amine plants treating gas containing H2S will have iron sulphides in the system. Are iron sulphides a good or bad thing? When do they help and when do they hinder? They are known for many things: forming protective films but yet promote fouling and are pyrophoric. The original paper attempted to clarify the pros and cons of iron sulphides present in an amine system. This paper will build on another 20 years of experience and knowledge gained through troubleshooting 100’s of amine units around the globe, specifically targeting guidelines on operating low pressure units like Acid Gas Enrichment (AGE) and Tail Gas Treating Units (TGTU), both becoming more prevalent in Middle East gas production.