A new approach for developing exact local composition models for lattice fluids
Journal
Journal of the Taiwan Institute of Chemical Engineers
Journal Volume
96
Pages
63-73
Date Issued
2019
Author(s)
Liu T.-C.
Abstract
In this work, we propose a novel approach for obtaining thermodynamic properties of lattice fluids based on local compositions. Rather than imposing a prescribed function for local compositions (e.g., the Boltzmann distribution as in most conventional local composition models), the local composition is determined based on minimization of free energy of the system in this new approach. This is made possible by expressing the potential energy and entropy (all possible arrangements of species on the lattice) of a system in terms of a given bulk and local composition. We show that the model resulted from this approach coincides with the well-known Ising model for a binary mixture in one-dimension with an interchangeable chemical reaction. However, this new model is applicable even when the species are not interchangeable, and therefore the free energy surface at all possible composition can be obtained. In the infinitely large lattice, this model also coincides with the COSMO-SAC model. This model could serve as a valuable basis for development of local composition models of more complicated systems. ? 2018 Taiwan Institute of Chemical Engineers
Subjects
COSMO-SAC
Entropy
Ising model
Lattice fluids
Local composition
SDGs
Type
journal article