Reclamation of Spent Automobile Engine Lubricating Oil

Abstract

In this study, some of the property reclamation methods for spent lubricating oil (SLO) were demonstrated. Firstly, 3.5 L of SLO was subjected to physical methods such as natural settling, sedimentation, magnetisaton and filtration to remove all forms of particles irrespective of size. The remaining samples were either subjected to acid treatment using concentrated sulphuric acid or solvent treatment using methanol, butanol and toluene including their blends to study their performance in the extraction process to recover the lubricating oil. The key parameter considered is the volume ratio of solvent/acid to used lubricating oil. In all, 5, 10, 15 and 20 ml respectively were used for each of the treatments. Activated carbon was equally introduced as adsorbent. A ratio of 4:1 (B20 formulation) for the treated spent oil and additives was used in this study for the final reclamation of the spent oil. The performance of each of the treatments process was investigated by subjecting all samples to laboratory analysis using American Standards for Testing and Methods (ASTM) to evaluate certain lubricating/tribological properties such as density, viscosity, pour point, cloud point etc. Both virgin oil and used oil were also simultaneously subjected to analysis with other recovered oil samples. The results suggest that the oil recovered by solvent treatments, particularly methanol exhibited better lubricating properties and can be rendered as good as virgin lubricants with the addition of certain additives. However, acid treatment demonstrated improved colour and appearance recovery compared to solvents. Keywords: Tribological properties, viscosity, pour point, cloud point