Chapter 6 - Modern fundamental equations of state for the most important hydrocarbons of oil, gas condensates, and associated gases

Abstract

This chapter presents the most accurate modern fundamental equations of state of technically important hydrocarbons and associated gases that form a part of oil, gas condensates, and natural and liquefied gases. For most hydrocarbons, the original fundamental equations of state developed by the authors are presented. The development of equations is carried out based on the authors' and selected literature data on various thermodynamic properties. For the authors' equations, the results of comparison with experimental data are given, which makes it possible to objectively assess their accuracy. To calculate the thermodynamic properties of insufficiently studied hydrocarbons, it is proposed to use generalized equations of state developed within the framework of the theory of thermodynamic similarity. A critical analysis of the published generalized equations is carried out; the area of their applicability is shown, and predictive capabilities are evaluated. The authors developed two generalized fourteen-constant fundamental equations of state, designed respectively to calculate the thermodynamic properties of n-alkanes and hydrocarbons with cyclic structures—naphthenes, arenes, and hybrid hydrocarbons (with six or more carbon atoms). To calculate the thermodynamic properties of hydrocarbons in the critical region, individual crossover equations of state are developed, and for predictive calculations, it is proposed to use the authors' generalized crossover equation of state.