Phase equilibria in multi-ring aromatic compounds

The goal of this work is to develop a thermodynamic model for phase coexistence calculations in coal derived fluids. Coal liquid mixtures consist of a very large number of aromatic and substituted aromatic compounds. In such mixtures it is often not practical ---indeed may be impossible---to perform the extensive chemical analysis needed to determine the concentrations of all components. The thermodynamic model has a firm thermodynamic basis and may be used from low to moderately high pressures. The chemical potentials are calculated using a fugacity coefficient expression for the vapor phase and an activity coefficient correlation for the liquid phase. The UNIFAC group contribution method has been used to calculate liquid phase activity coefficient. The Hayden--O'Connell correlation has been used to calculate vapor phase fugacity coefficient. The UNIFAC groups and their group parameters, and the thermophysical properties required in the model are defined in terms of groups used in the characterization procedure. 20 refs., 6 tabs.