Viscosity of binary mixtures of hydrogen and natural gas (hythane) in the gaseous phase

This work presents new measurements of the viscosity of pure and four binary mixtures of hydrogen and natural gas containing 5%, 15%, 30%, and 75% (molar) of hydrogen, respectively. Measurements were carried out in an oscillating-disk viscometer at pressures from 0.1 to 7.1 MPa in the temperature range from 298 to 400 K. The estimated uncertainty of the reported viscosities is +/-0.5% at atmospheric pressure and +/-1% at higher pressures. The experimental viscosity values at low pressure were used to determine the binary interaction parameters sigma(12) and epsilon(12)/kappa. These parameters secure the optimum representation of the data with the aid of the kinetic theory of gases for binary mixtures developed by Hirschfelder et al. The pressure dependence of the viscosity of the mixture is presented with the aid of the excess viscosity method. For the investigated supercritical :temperature range, a temperature dependence of the excess viscosity was not observed and it can be correlated as a function of density only.