Reference quality vapor-liquid equilibrium data for the binary systems methane + ethane, + propane, + butane, and + 2-methylpropane, at temperatures from (203 to 273) K and pressures to 9 MPa

A specialized cell designed for vapor liquid equilibrium (VLE) measurements at cryogenic temperatures and high pressures was used to measure new (p,T,x,y) data for binary mixtures of methane + ethane, + propane, + 2-methylpropane (isobutane), and + butane from (203 to 273) K at pressures up to 9 MPa. A literature review of VLE data for these binary mixtures indicates that a significant number have large uncertainties; however, because estimates of uncertainties in measured phase compositions are often not quantified sufficiently, it can be difficult for equation of state (EOS) developers to identify which data sets are of poor quality. Robust quantitative uncertainties were estimated for the VLE data acquired in this work, which allowed the identification of literature data sets that should not be included in future EOS development. The new data were compared with the predictions of the Peng–Robinson (PR) EOS and the Groupe European de Recherche Gaziere (GERG-2008) multiparameter EOS. The former describes...