THE THERMODYNAMIC BEHAVIOR OF THE CO2-H2O SYSTEM FROM 400-K TO 1000-K, UP TO 100 MPA AND 30-PERCENT MOLE FRACTION OF CO2

A model is presented for the thermodynamic properties of the aqueous m ixture of carbon dioxide, up to 30 mol% composition, in a large range of temperatures (400-1000 K) and pressures (0-100 MPa) around the crit ical point of water. The model for the Helmholtz free energy of the mi xture is based on the principle of generalized corresponding states, w ith the NBS/NRC Steam Tables as the reference state for pure water. In put to the model are data for the critical line of the mixture, appare nt molar volume and pVTx data in supercritical water, phase boundaries , excess enthalpies and mixture second virial coefficient data. Compar isons are presented with those data, with Henry's constants and with o ther formulations available for this system. Phase boundaries and tabu lated values of molar volumes, enthalpies, and fugacities are presente d along 35 isobars from 0.05 to 100 MPa, for four compositions, x = 0. 05, 0.10, 0.20 and 0.30, respectively, at 19 temperatures in the range of 400 to 1000 K. For the same pressures and temperatures, we also li st the infinite-dilution (standard state) properties: partial molar vo lume, enthalpy, heat capacity and fugacity coefficient of the solute C O2. The Fortran codes for generating these properties are listed in Ap pendix B.