In the lubricating oil manufacturing process, the aromatic content of vacuum distillates is reduced by solvent extraction, frequently with furfural. In this work, a method based on average pseudo-components properties is developed to calculate physical properties (density, refractive index and sulfur content) of hydrocarbon mixtures. Obtained values were compared to those calculated by other methods reported in the literature, obtaining similar results. In order to simulate the extraction operation, a model based on a reduced number of pseudo-components and the NRTL model is reported for the system furfural+SPD lubricating oil. Thereafter, the extraction operation was simulated by using such model and Aspen Plus (R) commercial software. Good agreement was found between predicted and experimental values of yield, furfural content, composition and physical properties for raffinates and extracts. (c) 2006 Elsevier Ltd. All rights reserved.