Aspen Physical Property System - Physical Property Models

Harlacher and Braun, "A Four-Parameter Extension of the Theorem of
Corresponding States," Ind. Eng. Chem. Process Des. Dev., Vol. 9, (1970), p.
479.
W. Wagner, Cryogenics, Vol. 13, (1973), pp. 470-482.
D. Ambrose, M. B. Ewing, N. B. Ghiassee, and J. C. Sanchez Ochoa "The
ebulliometric method of vapor-pressure measurement: vapor pressures of
benzene, hexafluorobenzene, and naphthalene," J. Chem. Thermodyn. 22
(1990), p. 589.
API Sour Model
The API Sour model is based on the API sour water model for correlating the
ammonia, carbon dioxide, and hydrogen sulfide volatilities from aqueous sour
water system. The model assumes aqueous phase chemical equilibrium
reactions involving CO2, H2S, and NH3. The model is not usable with chemistry
in the true component approach. Use the apparent component approach with
this model.
The model is applicable from 20 C to 140 C. The authors developed the model
using available phase equilibrium data and reported average errors between
the model and measured partial pressure data as follows
Compound Average Error, %
Up to 60 C Above 60 C
Ammonia 10 36
Carbon dioxide 11 24
Hydrogen sulfide 12 29
Detail of the model is described in the reference below and is too involved to
be reproduced here.
Reference
New Correlation of NH3, CO2, and H2S Volatility Data from Aqueous Sour
Water Systems, API Publication 955, March 1978 (American Petroleum
Institute).
Braun K-10 Model
The BK10 model uses the Braun K-10 K-value correlations, which were
developed from the K10 charts (K-values at 10 psia) for both real and pseudo
components. The form of the equation used is an extended Antoine vapor
pressure equation with coefficients specific to real components and pseudo
component boiling ranges.
This method is strictly applicable to heavy hydrocarbons at low pressures.
However, our model includes coefficients for a large number of hydrocarbons
and light gases. For pseudocomponents the model covers boiling ranges 450
– 700 K (350 – 800F). Heavier fractions can also be handled using the
methods developed by AspenTech.
2 Thermodynamic Property Models 187