In the crude benzene distillation process，there is a phenomenon of wash oil leakage in the separation cylinder.After dismantling the benzol stripper，large amount of oil residue on the tray is found at the inlet of the benzol stripper.The feed inlet is lowered by one layer of tray.The lean oil is observed to see if any change on its quality.As a result，the benzene containing in the lean oil has slightly increased，but due to the reduction of gas volume，the yield of light benzene has not decreased.

"> Crude benzene distillation, Wash oil leakage in separation cylinder,  , Benzol stripper maintenance