TY - JOUR
T1 - First-principles predictions of vapor-liquid equilibria for pure and mixture fluids from the combined use of cubic equations of state and solvation calculations
AU - Hsieh, Chieh Ming
AU - Lin, Shiang Tai
PY - 2009/3/18
Y1 - 2009/3/18
N2 - A novel approach combining first-principles solvation calculations and cubic equations of state is proposed for the prediction of phase equilibria of both pure and mixture fluids. The temperature and composition dependence of the energy parameter, a(T,x), in the EOS is determined from the attractive contribution to the solvation free energy. The volume parameter, b(x), is estimated to be the mole-fraction-weighted average volume of the molecular solvation cavity. This approach does not require the input of any experimental data (e.g., critical properties or acentric factor) for pure components and does not presume any composition dependence of the energy parameter. The Peng-Robinson EOS combined with a solvation model based on COSMO-SAC calculations, denoted as PR+COSMOSAC, is used to illustrate the applicability of this approach. It is found that the relative error from PR+COSMOSAC is 48% in vapor pressure, 21% in liquid density at the normal boiling point, 10% in critical pressure, 4% in critical temperature, and 5% in critical volume for 1295 pure substances and 27.56% in pressure and 5.18% in vapor-phase composition for 116 binary mixtures in vapor-liquid equilibrium. The errors in binary mixtures can be reduced significantly to 6.24% and 2.25% if experimental vapor pressures are used to correct for any errors in the calculated charging free energies of pure species.
AB - A novel approach combining first-principles solvation calculations and cubic equations of state is proposed for the prediction of phase equilibria of both pure and mixture fluids. The temperature and composition dependence of the energy parameter, a(T,x), in the EOS is determined from the attractive contribution to the solvation free energy. The volume parameter, b(x), is estimated to be the mole-fraction-weighted average volume of the molecular solvation cavity. This approach does not require the input of any experimental data (e.g., critical properties or acentric factor) for pure components and does not presume any composition dependence of the energy parameter. The Peng-Robinson EOS combined with a solvation model based on COSMO-SAC calculations, denoted as PR+COSMOSAC, is used to illustrate the applicability of this approach. It is found that the relative error from PR+COSMOSAC is 48% in vapor pressure, 21% in liquid density at the normal boiling point, 10% in critical pressure, 4% in critical temperature, and 5% in critical volume for 1295 pure substances and 27.56% in pressure and 5.18% in vapor-phase composition for 116 binary mixtures in vapor-liquid equilibrium. The errors in binary mixtures can be reduced significantly to 6.24% and 2.25% if experimental vapor pressures are used to correct for any errors in the calculated charging free energies of pure species.
UR - http://www.scopus.com/inward/record.url?scp=65349191781&partnerID=8YFLogxK
U2 - 10.1021/ie801118a
DO - 10.1021/ie801118a
M3 - 期刊論文
AN - SCOPUS:65349191781
VL - 48
SP - 3197
EP - 3205
JO - Industrial and Engineering Chemistry Research
JF - Industrial and Engineering Chemistry Research
SN - 0888-5885
IS - 6
ER -