The invention discloses a liquid-liquid extraction dearomatization process and
system, and belongs to the field of
petrochemical industry. According to the process, N, N '-dialkyl pyrrolidone and / or N, N'-dioxypyrrolidone is used as an extraction
solvent, and separation is completed through four steps of liquid-liquid extraction,
raffinate oil rectification, back extraction and
solvent and
aromatic hydrocarbon recovery. The
aromatic hydrocarbon selectivity and dissolving capacity are enhanced through the double-ring synergistic effect of the twin-structure
solvent, the problems that an existing monocyclic solvent is low in selectivity and large in agent-oil ratio, and
water washing is needed for solvent
recovery are solved,
raw material pretreatment and a cosolvent are not needed in the process, the
aromatic hydrocarbon recovery rate reaches 85% or above, the solvent recovery rate exceeds 91%, and the method is suitable for industrial production. The method is suitable for high-efficiency separation of aromatic hydrocarbons and non-aromatic hydrocarbons of various fuel oils such as straight-run diesel oil, catalytic diesel oil and reformed
gasoline.