A UNIFIED EQUATION OF STATE FOR FLUIDS OF C-H-O-N-S-AR COMPOSITION AND THEIR MIXTURES UP TO VERY HIGH-TEMPERATURES AND PRESSURES

A unified 3-parameter equation of state (EOS) for fluids of C-H-O-N-S-Ar composition based on molecular dynamical simulated data and on an approximation of intermolecular interaction with alpha-exponential-6 potential is shown to be valid at high pressure and temperature. The equation is parameterized for H2O, CO2, CH4, CO, O2, H-2, Ar, N2, NH3, H2S, SO2, COS, and S2 in the ranges of temperature (T) from 400 K (700 K for H2O) to 4000 K and pressure from 5 kbar to 1 000 kbar. The equation allows one to calculate any mixture of the fluid species in the system applying one-fluid approximation (i.e., using the alpha-exponential-6 parameters obtained by using mixing rules for the potentials of the pure species). The equation reproduces most of the available experimental data in the limits of experimental accuracy of volume (V) measurements.