Vapor – liquid equilibria (VLE) for water + atmospheric residue (AR) systems were measured at 603 – 643 K and 2.2 – 10.2 MPa by a flow type apparatus[1]. The AR was fractionated into 6 pseudo-components which were characterized by several major components via representative structure determined analyzed with the petroleomics analysis. The physical properties of each fraction were estimated by using a group contribution method. Correlation of experimental data by Peng-Robinson model[2] (PREOS) allowed to accumulate the interaction parameter kij data of water – AR fractions. Consequently, we could propose an empirical equation for predicting kij in VLE calculation with PREOS based on the obtained physical properties.
