Fitted functions that correlate binary
interaction parameters (BIP)
for the perturbed-chain statistical associating fluid theory (PC-SAFT)
equation of state (EoS) with the carbon number of n-alkanes were established for gas solubility in n-alkanes using solubility data of gases in a few selected n-alkanes typically with 10–28 carbon atoms. Data
screening was made to ensure accuracy and consistency of data used
for parametrization and validation. The PC-SAFT EoS using the BIPs
by the established fitted functions was evaluated against experimental
data. It was found that the PC-SAFT EoS is quantitatively accurate
for the entire homologous series of n-alkanes, regardless
of whether the data of n-alkanes were used in the
parametrization. It was shown that the PC-SAFT EoS successfully reproduces
the two types of the temperature dependence of gas solubility: (1)
gas solubility decreases with an increasing temperature and then increases;
(2) gas solubility always increases with an increasing temperature.
In particular, the PC-SAFT EoS is capable of predicting an experimentally
observed linear relationship between gas solubility in n-alkanes and the carbon number of n-alkanes. To
put it into perspective, the PC-SAFT EoS was compared to a couple
of popular benchmark group-contribution (GC) EoSs, namely, the predictive
Soave–Redlich–Kwang (SRK) EoS and the SRK EoS with the
modified Huron–Vidal second-order mixing rule. It was found
that the two models generally deliver much worse results than the
PC-SAFT EoS despite their satisfactory performance for gas solubility
in lighter n-alkanes. The PC-SAFT EoS and other cubic
EoSs with improved accuracy in modeling of asymmetric mixtures compared
to the above benchmark models were validated against experimental
data of synthetic gas condensates. It was found that the PC-SAFT EoS
is superior to the other models. The comparison was also made among
different parametrization strategies, namely, GC-PC-SAFT, the one
proposed in this study, and a four-parameter correlation for the simplified
PC-SAFT EoS. It was shown that the PC-SAFT EoS parametrized in this
study yields more accurate results, although the other two approaches
also give satisfactory performance.