Molecular dynamics simulations of the properties of CO2-H2O mixtures at high pressures and temperatures

Molecular dynamics simulations of CO₂-H₂O mixtures have been made at X_CO2 of 0.25, 0.5, and 0.75 using the TIP4P and MSM3 intermolecular potentials. At approximately 400°C and at pressures between 2 and 5 kbar the predicted excess volumes of about 1-2 cm³/mol agree very well with the available experimental data. Although excess volumes rapidly decrease with pressure, at both 400 and 1200°C the simulations predict that significant excess volumes of about 0.5 cm³/mol persist to pressures of over 20 kbar. In addition, the MD simulations predict only a small decrease in excess volumes as temperature is increased from 400 to 1200°C. -Authors