EOS-LNG: A Fundamental Equation of State for the Calculation of Thermodynamic Properties of Liquefied Natural Gases (LNG)
Monika Thol, Markus Richter, Eric F. May, Eric W. Lemmon, Roland Span
A new mixture model (EOS-LNG) for the accurate representation of thermodynamic property data of multicomponent natural gas mixtures in the liquid state region is presented. The mathematical approach of the GERG-2008 nist-equation of state of Kunz and Wagner is adopted and new binary- specific functions for methane + n-butane, methane + isobutane, methane + n-pentane, and methane + isopentane are developed. The representation of all experimental data available in the literature for the corresponding binary systems is carefully analyzed so that these functions can also be applied at fluid states beyond the liquefied natural gas region. The EOS- LNG represents all available binary and multicomponent data in the liquefied natural gas region within their specified experimental uncertainty, which is significantly more accurate than the GERG-2008 model. The main focus was given to the representation of new density data measured between 100 K and 180 K with a maximum pressure of 10 MPa. Deviations from the EOS-LNG presented here do not exceed 0.02 % for binary data and 0.05 % for multicomponent systems. Data in different fluid regions are mostly represented as well as with the GERG-2008 model.