Isothermal vapor–liquid equilibrium in CH4/H2/N2 system at a cryogenic temperature range from 100.0 K to 125.0 K

Isothermal vapor–liquid equilibrium data for CH4/H2/N2 system are determined by an experimental apparatus based on the static analytic method at a temperature range from 100.0 K to 125.0 K, corresponding to pressure above atmospheric pressure up to 4.5 MPa. Meanwhile, GERG-2008 equation of state is used to calculate the vapor–liquid equilibrium data for CH4/H2/N2 ternary system with a good consistence. The maximum absolute liquid composition deviations are 0.0033 and 0.0011 for hydrogen and nitrogen, respectively. And the maximum absolute vapor composition deviations are 0.0869 and 0.0203 for hydrogen and nitrogen, respectively. In addition, Peng–Robinson (PR) equation of state is used to correlate the experimentally measured pressure–temperature–liquid phase compositions (p–T–xi) for CH4/H2 binary system to propose a temperature-dependent interaction coefficient kij for CH4/H2 system which improves the calculation accuracy in vapor–liquid equilibrium for mixtures containing hydrogen and methane.