Thermodynamic Modeling of Multicomponent Mixtures in Industrial Applications

Abstract

The design, optimization and safe operation of separation, reaction and transport processes in the chemical, petroleum, gas and energy industries rest on accurate descriptions of how multicomponent mixtures behave. Thermodynamic models translate molecular interactions into quantitative predictions of phase equilibria, densities, enthalpies and other properties needed by process simulators. This article reviews the principal approaches to modeling multicomponent mixtures, beginning with the thermodynamic criteria for equilibrium and proceeding through cubic equations of state, mixing rules, activity coefficient models, association-based equations such as SAFT and CPA, and electrolyte models. Methods for estimating parameters from experimental data and numerical algorithms for stability analysis and flash calculations are discussed, followed by industrial applications and selection guidelines. The review emphasizes that model choice should be guided by the chemical nature of the system, the pressure and temperature range and the quality of available data, and that extrapolation beyond the fitted domain demands careful validation.