Binary interaction parameters of CO2−heavy-n-alkanes systems by using Peng–Robinson equation of state with modified alpha function

A generalized temperature-dependent binary interaction parameter (BIP) correlation has been developed for CO2−heavy-n-alkanes binary systems by using the Peng–Robinson equation of state (PR EOS) with the modified alpha function. The extensive experimentally measured vapour–liquid equilibria (VLE) data of CO2−heavy-n-alkanes systems in the temperature range of 277.59–663.75 K have been collected, including a series of heavy−n-alkanes from n-decane (n-C10H22) to n-tetratetracontane (n-C44H90). The BIP is found to be not only sensitive to temperature, but also decreased with carbon number of n-alkane. A BIP correlation for CO2−heavy-n-alkanes systems is then developed as a function of both the reduced temperature of CO2 and acentric factor of n-alkane. The newly proposed BIP correlation coupled with the modified alpha function in the PR EOS is found to be able to accurately reproduce 546 measured data points included in the database with an overall AARD of 4.7%. As for the 16 data points for CO2−n-C20H42 systems and 15 data points for CO2−n-C16H34 systems which are excluded in the database, a preferable prediction is respectively obtained by this work with AARDs of 6.6% (n-C20H42) and 6.5% (n-C16H34) in comparison of 20.9% (n-C20H42) and 12.6% (n-C16H34) from an existing correlation. Finally, it is shown that the newly developed BIP correlation can be well incorporated in the PR EOS with two original alpha functions.