Abstract
A novel low temperature process to recover base oil from waste lubricating oil is proposed in this study, which is based on solvent extraction with membrane. In this process, organic solvent is circulated in a closed loop, representing a resource saving technology. Residue consists of only impurities in waste lubricating oil, such as suspended particles, aqueous droplets, soot and tar, representing a waste reducing technology. This process includes a fractional distillation, too, but it is for separating out organic solvent from oils. Then, temperature for fractional distillation is lower than 100 degC, representing energy saving technology. Rubber film is utilized as membrane in this process. Rubber film has swelling property when it is immersed in organic solvent. Expanded polymer network structure works as filter to separate impurities from oil dissolved in solvent. Objective in this paper is to verify the feasibility of solvent extraction with rubber membrane to recover base oil from waste lubricating oil. Effect of extraction period, solvent volume and extraction temperature on both yield and quality of the extracted oil was experimentally estimated. Quality of extracted oil was evaluated through measurement of sulfur, carbon residue and carbon number distribution in oil molecules.
