Aspen Physical Property System - Physical Property Models

Alpha function Model name First Option code
Mathias-Copeman ESPRWS0, ESPRWS
ESPRV20, ESPRV2
Schwartzentruber-
Renon-
Watanasiri
References
2 Thermodynamic Property Models 73
ESPRWS0, ESPRWS
ESPRV20, ESPRV2
2
2
3 (default)
3 (default)
J. F. Boston and P.M. Mathias, "Phase Equilibria in a Third-Generation Process
Simulator" in Proceedings of the 2nd International Conference on Phase
Equilibria and Fluid Properties in the Chemical Process Industries, West Berlin,
(17-21 March 1980) pp. 823-849.
D.-Y. Peng and D.B. Robinson, "A New Two-Constant Equation-of-state," Ind.
Eng. Chem. Fundam., Vol. 15, (1976), pp. 59-64.
P.M. Mathias and T.W. Copeman, "Extension of the Peng-Robinson Equationof-state
To Complex Mixtures: Evaluation of the Various Forms of the Local
Composition Concept",Fluid Phase Eq., Vol. 13, (1983), p. 91.
J. Schwartzentruber, H. Renon, and S. Watanasiri, "K-values for Non-Ideal
Systems:An Easier Way," Chem. Eng., March 1990, pp. 118-124.
G. Soave, "Equilibrium Constants for a Modified Redlich-Kwong Equation-ofstate,"
Chem Eng. Sci., Vol. 27, (1972), pp. 1196-1203.
C.H. Twu, J. E. Coon, and J.R. Cunningham, "A New Cubic Equation of State,"
Fluid Phase Equilib., Vol. 75, (1992), pp. 65-79.
C.H. Twu, D. Bluck, J.R. Cunningham, and J.E. Coon, "A Cubic Equation of
State with a New Alpha Function and a New Mixing Rule," Fluid Phase Equilib.,
Vol. 69, (1991), pp. 33-50.
Soave Alpha Functions
The pure component parameters for the Redlich-Kwong equation-of-state are
calculated as:
These expressions are derived by applying the critical constraint to the
equation-of-state under these conditions:
Note: You can choose any of the alpha functions described here, but you
cannot define multiple property methods based on this model using different
alpha functions within the same run.
In the Redlich-Kwong equation-of-state, alpha is:
(1)
(2)
(3)