THERMODYNAMIC MODELLING OF MULTIPHASE EQUILIBRIA OF BINARY WAXY SYSTEM WITH PERTURBED-CHAIN STATISTICAL ASSOCIATION FLUID THEORY EQUATION OF STATE

Wax components containing paraffinic compounds may cause many problems in all fields of oil industry that make major subjects in economical part of industries. Thermodynamic modeling and multiphase equilibrium diagrams of systems containing waxy components can help to eliminate or at least prevent waxy problems. In this research, multiphase equilibrium diagrams of methane-heptadecane system is modeled by three activity coefficient models for solid phase and the Perturbed-Chain Statistical Association Fluid Theory equation of state for vapor and liquid phases. The results from the model are compared to available experimental data. The predictive Wilson activity coefficient model is found to be the best model with minimum average absolute relative deviation for solid-liquid equilibria and vapor-liquid-solid equilibria.