Second and Third Virial Coefficients for Methane + Ethane and Methane + Ethane + Carbon Dioxide at (300 and 320) K

Abstract

Measurements of pVT made using the Burnett technique at (300 and 320) K are reported for methane, ethane, three x1 methane + (1 − x1) ethane mixtures with x1 = 0.30623, 0.49971, and 0.70090, and two x1 methane + x2 ethane + (1 − x1 − x2) carbon dioxide mixtures with x1 = 0.32125, x2 = 0.34099 and x1 = 0.24759, x2 = 0.56013. Second virial coefficients have been calculated from these results for the pure fluids, and the binary and ternary mixtures. Cross second and third virial coefficients have been derived, including the cross third virial coefficient which describes the simultaneous unlike interaction between methane, ethane, and carbon dioxide. The experimental results were used to test an approximation to the virial equation which greatly simplifies calculations for multicomponent mixtures and which requires only experimental virial coefficients for binary mixtures. Values calculated using the model agree with experimental values within the estimated uncertainties. The results are compared with literat...