METHOD OF REMOVING HYDROGEN SULFIDE FROM CRUDE OIL Russian patent published in 2004 - IPC

FIELD: crude oil treatment. SUBSTANCE: invention relates to methods for removal of hydrogen sulfide from crude oil, gas condensate, their mixtures, and water-oil emulsions and can be used in oil and gas production and petroleum processing areas for deodorizing purification of hydrogen sulfide- and mercaptan-containing oils. Claimed method is implemented by treating initial feedstock with water-alkali solution of water-soluble nitrite salt, preferably alkali metal or ammonium nitrite, with pH at least 10 and nitrite concentration 3 to 40%. Solution is used on the basis of 0.9 to 5 mole nitrite per 1 mole hydrogen sulfide at treatment temperature 20 to 100^o, preferably 30 to 80^o, and at atmospheric or elevated pressure. Alkali agent in water-alkali solution is selected from water-soluble organic amines (alkanolamines) and/or ammonia, and/or sodium hydroxide. A part of exhausted solution, after separating it from purified feedstock, is recycled into process and the rest of exhausted solution is used for preparing fresh water-alkali nitrite solution. When high-sulfur oil containing hydrogen sulfide and mercaptans is purified, compressed air is additionally introduced into reaction mixture in amount 0.06-0.12 m₃ per 1 mole hydrogen sulfide and 2 mole methyl- and ethylmercaptans together with aqueous or water-alkali solution of variable-valence metal salt or complex preferably taken on the basis of 0.1-1.5 metal ions per 1 t feedstock. Process is carried out at pressure within a range of 0.1 and 1 MPa. EFFECT: enhanced process efficiency and widened assortment of noncorrosive, accessible and inexpensive neutralizing reagents under oil-field conditions. 11 cl, 13 ex