An improved Helmholtz energy model for non-polar fluids and their mixtures. Part 1: Application to non-polar pure fluids

An improved Helmholtz energy model for non-polar fluids and their mixtures. Part 3: Application to natural gases and related systems

“…On the one hand, the mixture model could readily meet the above requirement on the extension to more fluids because of its formulation as an extended corresponding states (ECS) model. Indeed, in the work of [1] coefficients were reported for ethylene, benzene and toluene, which are fluids that Kunz et al [4] reported to be further incorporated into the GERG-2004 equation. On the other hand, and more importantly, it was shown in [2] that the mixture model meets the requirements on accuracy of the current multi-fluid mixture models [9].…”

“…The calculation of caloric properties requires the perfect-gas isochoric heat capacity, c pg V,m . To that effect, a variety of correlations for c pg V,m /R were used in the work of [1], which were reproduced here for convenience. The following ancillary equations associated with reference equations of state were used: Setzmann and Wagner [12] for methane, Span et al [14] for nitrogen, Span and Wagner [15] for carbon dioxide and Stewart et al [16] for oxygen.…”

“…those by Estrada-Alexanders and Trusler [17] for ethane, Trusler and Zarari [18] for propane, Ewing and Goodwin [19] for i-butane, Ewing et al [20] for n-butane, Ewing and Goodwin for isopentane [21] and Ewing et al [22] for n-pentane. Finally, in the work of [1] correlations had been fitted to perfectgas isobaric-heat-capacity data by Pitzer and Kilpatrick [23] for n-hexane, Stephan and Hildwein [24] for n-heptane, Hossenlopp and Scott [25] for n-octane. For argon, c pg V,m /R = 1.5.…”

“…This is the third publication in a series [1,2] that presented a Helmholtz energy model for the prediction of thermodynamic properties of non-polar fluids and their mixtures. The work presented in [1] presented the development of the Helmholtz energy model and its application to 18 non-polar fluids comprising light and medium hydrocarbons and inorganic compounds whereas the extension to binary, ternary and quaternary mixtures of those fluids was documented in [2].…”

“…The work presented in [1] presented the development of the Helmholtz energy model and its application to 18 non-polar fluids comprising light and medium hydrocarbons and inorganic compounds whereas the extension to binary, ternary and quaternary mixtures of those fluids was documented in [2]. The main objective of this work is to build on the satisfactory performance of the mixture model of [2] to apply and further adapt it to natural gases and related systems.…”