Abstract: Along with more strict environmental regulations and clean fuels standards，low aromatic solvent oils should also need further dearomatization. Based on moderate operating conditions，extractant can be recycled and obtain byproduct aromatics. Lquid-liquid extraction technology is widely used，but in view of the low-aromatics raw material，extractant research and development is the key problem. A novel composite solvent adding ethylene glycol to N,N-dimethylformamide（DMF） was used as extractant in separation of low concentration aromatic solvent oil. By considering the selective coefficient（S） and distribution coefficient（K） of toluene to optimize the formulation，the mass fraction of ethylene glycol in the composite extractant was 15% ，and it was suitable for extraction separation of aromatic content less than 15% raw materials. LLE data of DMF – toluene - heptane and DMF-ethylene glycol – toluene – heptane systems were measured at atmospheric pressure and 40℃. The experimental data were correlated using the Othmer-Tobias correlation. LLE data confirmed that the composite extractant was appropriate for low-aromatic raw materials dearomatization. The optimal operating conditions of the composite extractant separating aromatics from solvent oils were determined. When extraction temperature was 40℃，extraction time was 5min，phase separation time was 10min，single stage extractant oil mass ratio was 0.5，after seven-stage counter-current extraction，the aromatics mass fraction in solvent oils was reduced from 9.15% to 0.76%.

Key words: extraction, separation, aromatics, phase equilibria, solvents, selectivity

摘要： 随着环保要求的日益严格和清洁燃料的需求增加，低芳烃含量溶剂油亦需进一步脱芳烃。液液萃取脱芳技术因具有操作条件缓和、萃取剂可循环利用、可得到芳烃副产品等优势被广泛应用，但针对低芳烃含量的原料，萃取剂的研发是关键问题。本实验采用N,N-二甲基甲酰胺（DMF）+乙二醇复合萃取剂萃取分离低浓度芳烃溶剂油体系，从萃取剂对甲苯的选择性系数（S）和分配系数（K）两方面出发优化了脱芳萃取剂配方，确定乙二醇质量分数为15%的复合萃取剂适用于萃取分离芳烃质量分数小于15%的低芳烃原料。测定了常压、40℃时 DMF-甲苯-正庚烷和复合萃取剂-甲苯-正庚烷体系的液液相平衡数据，并用Othmer-Tobias 方程对实验数据进行关联。相平衡数据证实了复合萃取剂更适用于低芳烃原料油脱芳。将优化的复合萃取剂用于溶剂油脱芳烃，实验结果表明在萃取温度40℃、萃取时间5min、分相时间10min、单级剂油质量比0.5的操作条件下，经7级错流萃取，溶剂油的芳烃质量分数可从9.15%降至0.76%，具有一定的工业应用前景。

关键词: 萃取, 分离, 芳烃, 相平衡, 溶剂, 选择性