The production of high-quality oils, with viscosity indices and thermal performance suited to international standards in Algeria

This study focuses on the production of high-quality lubricating oils with a high viscosity index by selectively extracting aromatic hydrocarbons, which tend to lower the viscosity index and the thermo-oxidative stability of the oils, using highly selective solvents. To selectively eliminate these aromatic hydrocarbons and increase the yield of raffinates, it is particularly important to achieve a high solvent selectivity for aromatics. Although furfural is commonly used to purify lubricating oils, it has limitations, such as low selectivity, limited efficiency toward aromatics, and poor thermal stability, which complicates its regeneration. In this work, we concluded that the most effective and selective solvent for cleaning lubricating oils of aromatic hydrocarbons is N-methylpyrrolidone and its mixture with ethylene glycol.