Aspen Physical Property System - Physical Property Models

Homologous series k wj
Acetylenes 0.348
Naphthenes 0.445
Cycloalkenes 0.355
Aromatics 0.315
aKD is the Kabadi-Danner term for water:
Where:
Gi is the sum of the group contributions of different groups which make up a
molecule of hydrocarbon i.
gl is the group contribution parameter for groups constituting hydrocarbons.
Groups Constituting Hydrocarbons and Their Group
Contribution Parameters
Group l g l , atm m 6 x 10 5
CH4 1.3580
– CH3 0.9822
– CH2 – 1.0780
> CH – 0.9728
> C < 0.8687
– CH2 – (cyclic) 0.7488
> CH – (cyclic) 0.7352
– CH = CH – (cyclic) † 0.6180
CH2 = CH2 1.7940
CH2 = CH – 1.3450
CH2 = C< 0.9066
CH � CH 1.6870
CH � C – 1.1811
– CH = 0.5117
> C = (aromatic) 0.3902
† This value is obtained from very little data. Might not be reliable.
The model uses option codes which are described in Soave-Redlich-Kwong
Option Codes.
SRK-Kabadi-Danner uses the same parameters as SRK, with added
interaction parameters. Do not specify values for the SRKLIJ parameters
when using SRK-KD.
62 2 Thermodynamic Property Models