INVESTIGATING THE EFFECT OF NMP/PHENOL SOLVENT BLEND ON LUBRICATING OIL PROPERTIES WITHOUT/WITH USING SURFACTANT

In this study, solvent extraction of lubricating oil to improve its viscosity index is investigated. A blend of phenol/NMP co-solvent was tested at different feed to solvent ratio 1:1, 1:1.5 and 1:2. Different percent of phenol (25%, 50% and 75%) in the co-solvent were studied. The conradson carbon residue, refractive index, viscosity at 40 oC and 100 oC, viscosity index and %yield of raffinate were measured. It was found that at constant extraction temperature of 65 oC and at constant mixing time of 15 minutes, best solvent blend was 25% phenol-75% NMP. Moreover, the effect of extraction temperature on the quality of raffinate was investigated using 25% phenol-75% NMP solvent blend and feed to solvent ratio of 1:2. Extraction temperatures up to 112 oC were tested. An optimum temperature of 103 oC was reached after which a deterioration in the quality of the raffinate is observed. Using surfactant as an additive in small quantities (0.01, 0.02, 0.05 and 0.1 wt.%) in the presence of 25% phenol-75%NMP as a solvent was studied. Temperature was held constant at 103 oC and feed to solvent ratio of 1:2 was used. An improvement in the properties of the raffinate was observed.