Cubic equations of state extended to confined fluids: new mixing rules and extension to spherical pores

Gabriel D. Barbosa, Michelle L. D'Lima, Shaden M.H. Daghash, Marcelo Castier, Frederico W. Tavares, Leonardo Travalloni

Index: 10.1016/j.ces.2018.03.047

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Abstract

The thermodynamic behavior of fluids confined in nanopores is highly influenced by the interaction between fluid molecules and pore walls. The most accurate approaches for modeling confined fluids are too computationally demanding for practical engineering requirements, such as process simulation. Thus, several efforts have been made to develop analytical equations of state suitable for confined fluids. The scope of this work consists of a modification to our previous modeling of fluid confinement in cylindrical pores based on cubic equations of state. By using new, more explicit mixing rules, a more consistent description of confined mixtures is obtained. Additionally, this modeling approach is extended to spherical pores. The proposed models displayed good predictive performance for the adsorption of binary and ternary mixtures, based on pure fluid adsorption data only, with an improvement relative to the previous modeling. It is shown that the adopted pore geometry can significantly affect the model performance.