Precise determination of the compressibility factor by using dielectric constant measurements

Abstract

Abstract We show that precise determination of the dielectric virial coefficients combined with the absolute value of the dielectric constant leads to very accurate values of the density. The higher order dielectric virial coefficients of the Clausius-Mossotti expansion are obtained by using an expansion technique. The compressibility factor of methane determined by using the first three dielectric virial coefficients is compared with the Goodwin equation of state. At 298.15 K and up to about 8 MPa, the compressibility factor calculated with the first two dielectric virial coefficients attains a difference of the order of 0.07% with the Goodwin equation of state. Between 8 MPa and 12 MPa, the first three dielectric virial coefficients are necessary to maintain the same order difference. The compressibility factor of methane determined by the dielectric method for two isotherms (298.15 K and 323.15 K) and pressures up to 15 MPa, compare with the best PVT and refractive index values.