Aspen Physical Property System - Physical Property Models

General Pure Component Ideal Gas Heat
Capacity
The Aspen Physical Property System has several submodels for calculating
ideal gas heat capacity. It uses parameter THRSWT/7 to determine which
submodel is used. See Pure Component Temperature-Dependent Properties
for details.
If THRSWT/7 is This equation is used And this parameter is
used
0 Ideal gas heat capacity
polynomial
2 Thermodynamic Property Models 219
CPIG
107, 127 DIPPR 107 or 127 CPIGDP
200-211 Barin CPIXP1, CPIXP2, CPIXP3
301 PPDS CPIGDS
401 IK-CAPE heat capacity
polynomial
503 NIST ThermoML
polynomial
CPIGPO
CPITMLPO
513 NIST Aly-Lee CPIALEE
These equations are also used to calculate ideal gas enthalpies, entropies,
and Gibbs energies.
Aspen Ideal Gas Heat Capacity Polynomial
The ideal gas heat capacity polynomial is available for components stored in
ASPENPCD, AQUEOUS, and SOLIDS databanks. This model is also used in
PCES.
Cp *,ig is linearly extrapolated using slope at
Parameter
Name/
Element
Symbol Default MDS Lower
Limit
Upper
Limit
Units
CPIG/1 C 1i — — — — MOLE-HEAT-CAPACITY,
TEMPERATURE
CPIG/2, ..., 6 C 2i, ..., C 6i 0 — — — MOLE-HEAT-CAPACITY,
TEMPERATURE
CPIG/7 C 7i 0 — — — TEMPERATURE
CPIG/8 C 8i 1000 — — — TEMPERATURE
CPIG/9, 10,
11
C 9i, C 10i, C 11i — — — — MOLE-HEAT-CAPACITY,
TEMPERATURE †
† If C10i or C11i is non-zero, then absolute temperature units are assumed for
C9i through C11i. Otherwise, user input temperature units are used for all
parameters. User input temperature units are always used for C1i through C8i.