Extraction of aromatic hydrocarbons from lube oil using n-hexane as a co-solvent

Liquid-liquid extraction is the most common method for extraction of aromatics from lube oil. Aromatic content of vacuum distillate is reduced by solvent extraction, frequently with furfural. The solvent power and selectivity of furfural can be further increased by using n-hexane as co-solvent. The aromatics in lube oil were extracted at different temperatures (ranging from 323.15 to 343.15 K) and different co-solvent to feed volume ratios (ranging from 0.0 to 0.5). The extraction temperature and the amount of n-hexane in furfural were investigated systematically in order to determine their optimum values. The amounts of aromatic, paraffinic and naphthenic compounds were determined using ASTM standards by measuring refractive index (RI), viscosity, molecular weight and sulfur content. It was found that using 11% n-hexane at 333.15 K yields the optimum extraction conditions.