PVTx and VLE properties of natural gases with a general Helmholtz equation of state. Part I: Application to the CH 4–C 2H 6–C 3H 8–CO 2–N 2 system]]>

摘要

AbstractA general equation of state (EOS) explicit in Helmholtz free energy has been developed to predict the pressure–volume-temperature-composition (PVTx) and vapor-liquid equilibrium (VLE) properties of the CH4–C2H6–C3H8–CO2–N2fluid mixtures (main components of natural gases). This EOS, which is a function of temperature, density and composition, with four mixing parameters used, is based on the improved EOS of Sun and Ely (2004) for the pure components (CH4, C2H6, C3H8, CO2and N2) and contains a simple generalized departure function presented by Lemmon and Jacobsen (1999). Comparison with the experimental data available indicates that the EOS can calculate thePVTxand VLE properties of the CH4–C2H6–C3H8–CO2–N2fluid mixtures within or close to experimental uncertainties up to 623K and 1000bar within full range of composition. Isochores of the CH4–C2H6–C3H8–CO2–N展开▼