Ammonium Bisulphide (Sour Water) Corrosion

Summary

Aqueous ammonium bisulphide (NH₄HS) solutions form when ammonia (NH₃) and hydrogen sulphide (H₂S) are absorbed in liquid water. Depending on the pH of the resulting aqueous solution, the absorbed H₂S may remain as dissolved H₂S, or it may dissociate into the bisulphide ion (HS^-) or the sulphide ion (S₂^-). In alkaline sour waters containing dissolved ammonia (typically with pH = 7 to 12), the bisulphide ion is the predominant sulphide species present.