Assessing the quality of SAFT equations for the vapor-liquid equilibrium of pure water

0572420 - ÚCHP 2024 RIV NL eng J - Journal Article
Klajmon, M. - Nezbeda, Ivo
Assessing the quality of SAFT equations for the vapor-liquid equilibrium of pure water.
Journal of Molecular Liquids. Roč. 376, APR 15 (2023), č. článku 121414. ISSN 0167-7322. E-ISSN 1873-3166
R&D Projects: GA ČR(CZ) GA20-06825S
Institutional support: RVO:67985858
Keywords : SAFT equations * vapor-liquid equilibria * water
OECD category: Chemical engineering (plants, products)
Impact factor: 6, year: 2022
Method of publishing: Open access with time embargo

The family of eight representative (and most commonly used) SAFT equations of state for water and the cubic-plus-association equation are examined with respect to their ability to predict accurately the vapor-liquid equilibrium (VLE) of water. The problem originates from the fact that all these equations use only the experimental equilibrium liquid densities and pressures for the parameter evaluation. Consequently, when reproducing the VLE calculations once the parameters are evaluated, the equilibrium properties cannot be then determined accurately by the equations, in principle, because the computation involves also the omitted vapor density. In this contribution, the errors of the predicted equilibrium den-sities, orthobaric pressures, and related properties are determined and discussed. It turns out that even the properties used in the equations' parametrizations (pressure and liquid density) are not always repro-duced with acceptable accuracy, with average errors being around two percent and errors of the individ-ual data points exceeding in many cases even ten percent. Properties not included in the parametrization are then predicted with larger average errors, in general.
Permanent Link: https://hdl.handle.net/11104/0343187