Abstract: The traditional aromatics extraction process requires the use of high temperature （180-240 ℃）steam at 1.0-1.3 MPa, which has the disadvantages of high energy consumption and high temperature leading to fast deterioration of solvent performance. In this paper, liquid-liquid extraction method at low temperature under atmospheric pressure was used to remove polycyclic aromatic hydrocarbons from FCC diesel. The operating conditions of extraction dearomatization, aromatics recovery, reverse extraction and solvent regeneration were investigated. The results showed that the optimal parameters for extraction dearomatization process were as follows: the agent A /FCC diesel volume ratio was 1.5, the extraction temperature was 50 ℃, the extraction time was 5 min, and the phase separation time was 5 min, the aromatics recovery conditions: agent B / (agent A + aromatics) volume ratio was 0.2, the extraction temperature was 50 ℃, the extraction time was 4 min and the phase separation time was 3 min. Under the optimal extraction conditions, the yield of mixed aromatics product was 29.29%, the mass fraction of mixed aromatic was 93.71%. The solvent was regenerated under the best reverse extraction conditions: agent C / (agent A + agent B) volume ratio was 0.2, reverse extraction 40 ℃ and 3 min, the phase separation time was 3 min, and vacuum distillation at 78℃. The extraction effect of the regenerated solvent was as good as the fresh one. Finally, the principle process of liquid-liquid extraction dearomatization for FCC diesel was proposed.

Key words: FCC diesel, polycyclic aromatics, extraction dearomatization, principle process