Aspen Physical Property System - Physical Property Models

Where:
Vm R,0 and Vm R,� are functions or Tr for
For , there is a linear interpolation between the liquid density at
Tr = 0.95 and the vapor density at Tr = 1.05. This model can be used to
calculate saturated and compressed liquid molar volume. The compressed
liquid molar volume is calculated using the Tait equation:
Where B and C are functions of T, �, Tc, Pc and P sat is the saturated pressure
at T.
Note: Reduced temperature Tr is always calculated using absolute
temperature units.
Mixing Rules:
Where:
To improve results, the Aspen Physical Property System uses a special
correlation for water when this model is used. Changing the VSTCTD and
OMGCTD parameters for water will not affect the results of the special
correlation.
Parameter
Name/Element
200 2 Thermodynamic Property Models
Symbol Default MDS Lower
Limit
Upper
Limit
Units
TC T ci — — 5.0 2000.0 TEMPERATURE
VSTCTD V r *,CTD
OMGCTD � r
References
VC X 0.001 3.5 MOLE-VOLUME
OMEGA X -0.5 2.0 —
R.W. Hankinson and G.H. Thomson, AIChE J., Vol. 25, (1979), p. 653.
G.H. Thomson, K.R. Brobst, and R.W. Hankinson, AIChE J., Vol. 28, (1982),
p. 4, p. 671.