Experimental liquid mixture densities for testing and improving correlations for liquefied natural gas



Liquid molar volumes and excess volumes have been experimentally determined for some methane-rich binary and ternary mixtures containing ethane, propane, isobutane, and nitrogen between 91 and 115 K. A gas expansion type system calibrated against pure methane densities was used to make the necessary pure fluid and mixture measurements.

The best of the available density correlations predicts the experimental methane-ethane molar volumes within ±0.2%, while larger systematic deviations are found for the methane-propane and methane-isobutane systems. Molar volumes for methane-nitrogen and ternary mixtures containing nitrogen diverge strongly from the correlation predictions at 108 K and higher temperatures. An empirical scheme is proposed for predicting molar volumes of methane-rich liquefied natural gases using reported methane-ethane and methane-nitrogen excess volumes. This method predicts all binary and ternary molar volumes from this investigation within ±0.1%.