FIELD: petroleum processing.
SUBSTANCE: cracked naphtha stream is separated into three fractions: light cracked ligroin, intermediate cracked ligroin, and heavy cracked ligroin. The latter is subjected to desulfurization in first desulfurization reactor. Stream leaving the first reactor is combined with intermediate cracked ligroin and resulting mixture is subjected to desulfurization in second desulfurization reactor. Stream leaving the second reactor can be combined with low-boiling naphtha to form a new naphtha with wide boiling temperature range, which contains on the whole much less sulfur than starting materials. Mercaptans in low-boiling naphtha can be removed either via thioetherification reaction before separation or by washing with alkali after separation.
EFFECT: enhanced sulfur removal efficiency due to olefin preserving treatment procedure.
11 cl, 2 dwg, 2 ex
