Abstract: The accumulation of heavy components in lean solvent occurs in the extraction-distillation process of pyrolysis gasoline after hydrogenation. The purification effect of sulfolane solvent were investigated by four methods: back-extraction of reffinate, water washing of lean solvent, water washing of rich solvent, and combination of back-extraction of raffinate and water washing. The results showed that among all the heavy components，the linear alkylbenzenes were the easiest to remove，while the separation of polycyclic aromatics were the most difficult；temperature had a certain influence on the removal of the heavy components，and the effect was different in different methods. The purification results of back-extraction and water washing coupling methods for raffinate were the best. The mass fraction of sulfolane in the lean solvent can increase from 94.25% to 99.86% under the following conditions：the ratio of raffinate to lean solvent of 1.0，the washing water to the solvent ratio of 1.0，the temperature of 40℃. The purified solvent meets the purity requirement of recycled lean solvent for industrial production.

Key words: sulfolane, heavy components, raffinate, back-extraction, water washing