A MOLECULAR-DYNAMICS STUDY OF THE PRESSURE-VOLUME-TEMPERATURE PROPERTIES OF SUPERCRITICAL FLUIDS .2. CO2, CH4, CO, O2, AND H-2

The method of molecular dynamics (MD) has been used to simulate the pressure-volume-temperature (PVT) properties of CO2, CH4, CO, O2, and H2. For the MD simulation, the exponential-6 form of the intermolecular potential has been adopted. The parameters of the potential are calculated from the available experimental PVT data. The MD-simulated results fit the experimental (static) PVT data well and are in reasonable agreement with the shock-wave P-V data. Based on both the experimental PVT and the MD-simulated data, equations of the type: P = a/V + b/V2 + c/V(n) have been formulated for each of the five fluids in the pressure range of 5 Kbar to 1 Mbar at temperatures from 400 to 4000 K. The calculated fugacity of CO2 has been used to show the consistency of the modeled data with the experimental phase equilibrium data on the reactions involving magnesite.