Generalised virial equation of state for natural gas systems

The GERG-2008 Wide-Range Equation of State for Natural Gases and Other Mixtures: An Expansion of GERG-2004

“…For the binary mixture methane–nitrogen, very accurate sound speeds were measured by Estela-Uribe, Trusler, and Estela-Uribe et al The measurements cover temperatures from (220 to 400) K at pressures up to 30 MPa for nitrogen mole fractions of 0.10 and 0.20 and temperatures from (170 to 400) K at pressures up to 16 MPa for a nitrogen mole fraction of 0.54. The mixture was studied along pseudoisochores at molar densities between 0.2 mol·dm –3 and 5 mol·dm –3 .…”

“…For density measurements, very accurate results were obtained using a two-sinker or single-sinker densimeter (e.g., Glos et al and Chamorro et al). Highly accurate sound-speed data were measured by means of spherical-resonators (e.g., Costa Gomes and Trusler, Estela-Uribe, and Trusler). Data that were measured with methods based on these particular techniques have uncertainties equal to or close to the lowest values listed in Table .…”

“…The data situation has been significantly improved over the past 15 years since new data for several binary mixtures were measured as a part of the GERG project “Reference Equation of State for Thermal and Caloric Properties of Natural Gases” (see Klimeck) and by numerous other independent authors. These include, for example, the very accurate measurements for gas-phase densities and sound speeds of the binary mixtures methane–nitrogen (Estela-Uribe, Trusler, Chamorro et al), methane–carbon dioxide (Estela-Uribe, Glos et al), methane–ethane (Costa Gomes and Trusler), and nitrogen–ethane (Trusler). For vapor–liquid equilibrium states, comparatively accurate data were reported, for example, for methane–ethane and nitrogen–ethane (Raabe et al), methane–carbon dioxide and methane–propane (Webster and Kidnay), propane– n -butane (VonNiederhausern and Giles), and propane–isobutane (VonNiederhausern and Giles, Lim et al).…”

High-precision virial coefficients of argon and carbon dioxide from integration of speed of sound data in the pressure–temperature domain

“…Accurate measurements of the second and third virial coefficients are useful for basic and applied research: for instance, they are used to constrain multi-parametric equations of state [1,2] and develop models of intermolecular interactions [3]. They also find application in the prediction of properties of natural gas systems [4,5], characterization of corrosive gases used in the production of semiconductors [6][7][8][9], and identification of the composition of gaseous mixtures [10,11]. As pointed out by Trusler [12], even if extensive experimental data are available for virial coefficients of simple fluids, new methods for determination or estimation of virial coefficients are important because of new applications that demand high precision data for previously-disregarded compounds, temperature ranges not covered by experiments, or newly-considered mixtures.…”

Calculation of intermolecular potentials for H 2 H 2 and H 2 O 2 dimers ab initio and prediction of second virial coefficients

“…Recently Estela-Uribe and Jaramillo [43] published empirical correlation equations for second virial coefficients which are based on the corresponding-states approach of Lee and Kesler [44]. In their work, binary interactions are characterized by so-called pseudocritical parameters, which are interpolations of the pure-fluid critical temperatures and densities: Here the Mi denote molar masses of the pure components, M ij an "interaction molar mass", and c is a constant (21.8 K g/mol) It turns out that the adjustable parameters a ij and d ij are very close to zero for a large number of chemical compounds.…”