A method is developed for calculating the static dielectric constant (relative permittivity) of fluid mixtures, with an emphasis on natural gas. The dielectric constant is calculated as a function of temperature, density, and composition; the density is calculated with a fundamental mixture equation of state. Theory-based correlations were developed for the dielectric constant of all significant components of natural gas, including not only the light hydrocarbons but also gases such as nitrogen and carbon dioxide. In many cases, these correlations took advantage of new, highly accurate data measured in cross capacitors. For mixtures, the pure-component values are combined as proposed by Harvey and Prausnitz; this produces better results than the traditional mixing rule.
Citation: International Journal of Thermophysics
Pub Type: Journals
dielectric constant, energy, mixtures, natural gas, polarization, relative permittivity