Today oil and gas condensate sweetening is solely applied to prepare them for transportation. In oil mercaptan compounds are represented by a wide variety from C1 to C15.
Requirements for oil treatment are applied only to light, most corrosive methyl and ethyl mercaptans, their total content should not exceed 0.004 % wt. Light (C1-C2) mercaptans removal from oil proceeds with alkaline solutions extraction and subsequent regeneration of alkali in the presence of phthalocyanine catalyst and oxygen. The resulting disulfide is not separated from the oil. Thus, the concentration of sulfur compounds in the oil is unchanged.
Hydrogen sulfide removal from oil proceeds at its physical stabilization effected with debutanization. In the EAEC (former USSR) oil and gas condensates treatment processes mainly used in Kazakhstan, where oil characterized by high content of mercaptan compounds. In Russia oil and gas condensates with high content of mercaptans are produced in Astrakhan, Orenburg and Samara regions.