Patents

A process for preparation of high performance lube base oils from spent lubricating oil and its distillate, wherein spent lubricating oil and its distillate are subjected to liquid- liquid extraction (LLE) using a selective dual solvent having a distinct composition [N- Methyl Pyrrolidone (NMP) or furfural or N-methyl morpholine (NMM) or Di-Methyl Formamide (DMF) or Dimethylsulfoxide (DMSO) or mixtures thereof containing some percentage of co-solvent such as water or ethylene glycol etc to adjust the selectivity and solvent power] to remove components responsible for poor quality of spent lubricating oil and its distillate, carbon soot particles and instability of color and the raffinate phase after solvent recovery by "water washing" is subsequently subjected to distillation under vacuum to obtain re-refined lubricating oils of different viscosity grades having better quality in terms of viscosity index (VI), color and other properties and to produce group - I, group - II, group - III re-refined lubricating base soils (RLBO) and the extract phase which can be used after recovery of solvent as a material for producing carbon rich products such as paving grade bitumen.