Generalised virial equation of state for natural gas systems

• Published in: Fluid phase equilibria 2005-04, Vol.231 (1), p.84-98
• Main Authors: Estela-Uribe, J.F., Jaramillo, J.
• Format: Article
• Language: English
• Subjects: Applied sciences; Chemical thermodynamics; Chemistry; Compression factor; Crude oil, natural gas and petroleum products; Density; Energy; Exact sciences and technology; Fuels; General and physical chemistry; General. Theory; Prospecting and production of crude oil, natural gas, oil shales and tar sands; Speed of sound; Virial coefficients; Virial equation of state
• ISSN: 0378-3812; 1879-0224
• DOI: 10.1016/j.fluid.2005.01.005

In this work we present a generalised virial equation of state for natural gas systems under custody transfer conditions. The model is based on corresponding states expressions for the second and third virial coefficients with argon as the reference fluid. These functional forms involve 12 adjustable coefficients. For the extension to mixtures we propose a one-fluid mixture model with binary interaction parameters in the combining rules for the mixture critical temperature and density. We obtained overall average absolute deviations (AAD) of 0.04 and 0.08% in pure-fluid compression factors and speeds of sound; AADs of 0.07 and 0.19% in compression factors and speeds of sound, respectively, of binary mixtures and AADs of 0.047, and 0.13% in natural gas compression factors and speeds of sound, respectively. These results compare favourably with equivalent calculations with other generalised virial coefficient models.