Refining and Dewaxing of Light Lubricating Oil Using Ethoxylated Anionic Surfactant as Additive for Extraction

Production of light lubricating oil by furfural extraction using surfactant as an additive followed by dewaxing with urea was investigated in the present study. An investigation was conducted in order to examine the effect of the addition of ethoxylated anionic surfactant (SLES—sodium lauryl ether sulfate) to the fraction of the light lubricating (spindle) oil during the solvent extraction process. The aromatics in the lube oil were extracted at different temperatures ranging from 60 to 70°C with different concentrations of surfactant (from 0.01 to 0.1 wt %). The operating conditions of the urea adduct formation with n-paraffins were studied in detail. The activator and the solvent used in dewaxing are acetone and gasoline, respectively. Pour point, viscosity index and yield of oil produced by different steps were determined to show the effect of the operating conditions. For an extraction carried out at the temperature of 70°C, the quality of the raffinate was obtained with an increase in the yield for 13.41 wt %, by using a concentration of 0.1 wt % in SLES. According to the experimental results obtained from dewaxing with the increase in the quantity of urea, the yield of dewaxed products decreases and the yield of normal paraffins increases. Urea dewaxing has a greater effect on the pour point of lower viscosity cuts, as adduct formation is selective for n-paraffins.