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Toward a molecular equation of state for real materials
Author(s) -
Fleming P. D.,
Brugman R. J.
Publication year - 1987
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690330505
Subject(s) - equation of state , characteristic equation , lattice (music) , thermodynamics , mathematics , mathematical analysis , physics , differential equation , acoustics
An equation of state based on molecular interaction concepts has been developed. This equation contains three parameters corresponding to a square‐well potential characterized by a molecular radius, a well depth, and a well width. It is obtained by perturbation theory with a hard sphere reference system and, with appropriate choice of parameters, yields good agreement with experimental PVT properties of 12 nonaqueous substances. The agreement is in all cases for superior to that obtained with the usual implementation of the Peng‐Robinson equation, and is better for most cases than that obtained by optimizing the parameters in the Peng‐Robinson equation. For water, neither the reported equation nor the Peng‐Robinson equation is in agreement with experiments. To obtain acceptable agreement, it is necessary to employ an equation that treats the particular geometry of attractive interactions characteristic of water. The Fleming‐Gibbs lattice equation of state for water does give reasonable agreement with PVT properties.