Measurement and correlation of high pressure phase behavior of carbon dioxide + water system

A visual and variable volume view cell analyzer was installed and the phase behaviors of the carbon dioxide + water system were measured in the temperature and pressure ranges from 313.2 K to 343.2 K and from 4.33 MPa to 18.34 MPa, respectively. The measured data were correlated with the MF-NLF-HB equation of state to consider the effects of the hydrogen bonding of the saturated liquid and vapor mixture. The calculated data agree well with the measured data within an absolute average error deviation of 5%. The fraction of hydrogen bonding could be calculated by the MF-NLF-HB EOS for the carbon dioxide + water system with the obtained VLE data. The calculated hydrogen bonding fraction of the saturated liquid phase of the mixture decreased with increasing pressure in the isothermal calculations. The hydrogen bond strength was affected by the concentration of carbon dioxide and solubility of carbon dioxide was affected by pressure. The calculated hydrogen bonding fraction of the saturated vapor phase of the mixture had a minimum value near 10 MPa for the three isothermal calculations.