Thermodynamic properties of water from SAFT and CPA equations of state: A comprehensive assessment

0559855 - ÚCHP 2023 RIV NL eng J - Journal Article
Nezbeda, Ivo - Klajmon, M. - Hrubý, Jan
Thermodynamic properties of water from SAFT and CPA equations of state: A comprehensive assessment.
Journal of Molecular Liquids. Roč. 362, Sep 15 (2022), č. článku 119769. ISSN 0167-7322. E-ISSN 1873-3166
R&D Projects: GA ČR(CZ) GA20-06825S; GA ČR(CZ) GA22-03380S
Institutional support: RVO:67985858 ; RVO:61388998
Keywords : SAFT equations * CPA equation * water * response functions
OECD category: Chemical engineering (plants, products); Thermodynamics (UT-L)
Impact factor: 6, year: 2022
Method of publishing: Open access with time embargo

The performance of eight versions of the representative and most commonly used Statistical-AssociationFluid-Theory (SAFT) equations of state for water along with the Cubic-Plus-Association (CPA) equation are examined in detail both throughout the entire liquid phase region and at supercritical conditions. In addition to the temperature-pressure dependence of density, the fundamental response functions, namely, isothermal compressibility, isobaric expansivity, and isobaric heat capacity, have been evaluated and compared with experimental data along five isobars from P = 0:1 MPa up to 1000 MPa, and along four isotherms within the range from 300 K to 750 K. It turns out that to draw a general conclusion on the quality and accuracy of these equations (for pure water) is practically impossible with different equations reproducing reasonably well different properties and at different thermodynamic conditions but failing in other instances. In general, the equations seem to be able to capture simple pressure dependence at isothermal conditions but fail primarily in estimating isobaric properties. All the equations tend to perform reasonably well at pressures above the critical one where the excluded volume begins to predominate and the effect of hydrogen bonding becomes insignificant, but fail again at very high pressures, and have the most serious problems with predicting the residual isobaric heat capacity. The most successful results are obtained from the recently developed Association Dependent PC-SAFT equation, which can be mainly attributed to its fitting using a broader set of experimental data compared to other equations, nonetheless, its performance still cannot be considered as overall reliable.
Permanent Link: https://hdl.handle.net/11104/0333038