Surface tension of chain molecules through a combination of the gradient theory with the CPA EoS
Advancing the chemical engineering fundamentals
Thermodynamics: Applications of Equations of State (T2-1b)
Keywords: CPA EoS, Gradient Theory, Surface Tension, Chain Molecules, Phase Equilibria
Despite the interest in systems containing associating and non-associating components such as alkanes, perfluoroalkanes, alcohols and water, their liquid-liquid interfaces have received little quantitative attention.
With the final aim of modeling simultaneously the phase equilibria and interfacial tensions of these systems, a combination of the gradient theory of fluid interfaces with the Cubic-Plus-Association (CPA) equation of state was selected.
The gradient theory of fluid interfaces is an appealing approach for modeling interfacial tensions. This model is based on the phase equilibria of the fluid phases separated by the interface, for what an adequate equation of state is employed. The CPA EoS combines the Soave-Redlich-Kwong (SRK) cubic equation of state for describing the physical interactions with the association contribution proposed by Wertheim, also used in other associating equations of state, such as the different versions of SAFT. The CPA EoS had already shown to be able to describe vapor-liquid and liquid-liquid equilibria of mixtures containing water, alkanes and alcohols.
As will be shown, both phase equilibria and surface tensions were accurately described, with average surface tension deviations below 1,2 %. A discussion on the regression and selection of pure component parameters is also presented, as well as some pure component results for the vapor pressure and equilibrium densities are reported.
Presented Monday 17, 16:20 to 16:40, in session Thermodynamics: Applications of Equations of State (T2-1b).
