A property-integration approach to solvent screening and conceptual design of solvent-extraction systems for recycling used lubricating oils

The significant quantities of used and discharged lubricating oils pose a major environmental problem around the world. Recently, there has been a growing interest in the sustainable usage of lubricating oils by adopting recovery, recycle, and reuse strategies. In this study, a property-integration framework is used in the optimization of solvent selection for re-refining of used lubricating oils. Property-integration tools are employed for the systematic screening of solvents and solvent blends. The proposed approach identifies the main physical properties that influence the performance of solvent(s) while extracting additives and contaminants from used lubricating oils (i.e., solubility parameter (δ), viscosity (v), and vapor pressure (p)). To identify a feasibility region for an effective solvent or solvent blend for this process, we construct a ternary diagram utilizing the property-clustering technique. The results of the theoretical approach are validated through comparison between experimental data for single solvents and for solvent blends.