Abstract: Using a third vacuum side dewaxed oil as feed, the pilot plant test of furfural extraction denitrogenation with assistant (metallic salt) added was introduced in this paper. Results showed that adding assistant in the furfural denitrogenation process could enhance the removal of basic nitrogen compounds in dewaxed oil significantly; the removal rate reached 97.6%. Under the optimum operation conditions of an extractor top temperature of 115 ℃, an extractor bottom temperature of 67 ℃, a solvent/oil volume ratio of 2.0 and an assistant adding amount of 8 g/kg(oil), the treated oil had a basic nitrogen content of 10.47 μg/g, its viscous index was 112 and its rotating bomb oxidation test time reached 211 min.

Key words: lube base oil, extraction, furfural refining, assistant, denitrogenation, pilot plant scale