Aspen Physical Property System - Physical Property Models

using
and
68 2 Thermodynamic Property Models
(22)
(23)
(24)
Using the association model, more different species occur than can be
distinguished. Thus, the equivalent expression for the entropy of mixing
should be written with the true concentrations. As eq. 24 refers to 1 mole
monomers, the expression should be weighted by the compressibility factor
representing the true number of moles. The new expression is
For �ga we obtain
and, analogously,
Parameter
Name/Element
Symbol Default MDS Lower
Limit
(25)
(26)
(27)
Upper
Limit
DMER/1 A i2 0 X – – –
Units
DMER/2 B i2 0 X – – TEMPERATURE
TMER/1 A i4 0 X – – –
TMER/2 B i4 0 X – – TEMPERATURE
HMER/1 A i6 0 X – – –
HMER/2 B i6 0 X – – TEMPERATURE
References
M. M. Abbott and H. C. van Ness, "Thermodynamics of Solutions Containing
Reactive Species, a Guide to Fundamentals and Applications," Fluid Phase Eq.,
Vol. 77, (1992) pp. 53–119.
V. V. De Leeuw and S. Watanasiri, "Modeling Phase Equilibria and Enthalpies
of the System Water and Hydrofluoric Acid Using an HF Equation-of-state in
Conjunction with the Electrolyte NRTL Activity Coefficient Model," Paper
Presented at the 13th European Seminar on Applied Thermodynamics, June
9–12, Carry-le-Rouet, France, 1993.