Predicting the Liquid Density of Gas Condensates and LNG Mixtures from Equations of State

Document Type : Research Paper



In this contribution, two approaches are followed to predict the saturated liquid density of liquefied natural gas (LNG) mixtures. In one approach, 12 cubic equations of state (EoSs), comprising the popular Peng-Robinson (PR) and Redlich-Kwong-Soave (RKS), are employed to predict the saturated liquid density of 20 LNG mixtures. In the other approach, these EoS are used in conjunction with a recently developed correlation to predict the liquid density of the same LNG mixtures. This correlation takes the advantages of the EoSs functions and is remarkably accurate for LNG mixtures. The results for both approaches are presented and the best predicting methods are ranked. Also the liquid density of 3 gas condensate mixtures are predicted using 10 EoSs and the results are compared with experimental data. The method employed is discussed and the best EoSs are ranked. Our evaluation indicates that in general, the EoSs used in this study are not accurate enough for predicting the liquid density of gas condensate mixtures. The PR, Patel-Teja (PT) EoSs or one of their variant are recommended, however.