Development of a novel Peng–Robinson plus association equation of state for industrially important associating compounds

Abstract

Cubic plus association (CPA) equations of state (EoSs) have found great interest in describing thermodynamic properties of associating fluids. In CPA EoSs, the association contribution proposed by Wertheim is added to cubic EoSs such as Soave–Redlich–Kwong (SRK) and Peng–Robinson (PR). In different developments of CPA EoSs, adjusting the pure component properties such as critical temperature and critical pressure in addition to the association parameters is proposed in some works in the literature. In this work, the PR EoS has been extended to water, phenol, and a number of alcohols (methanol up to dodecanol) by addition of the Wertheim association contribution. In contrast to other CPA EoSs, the experimental values of critical properties are used. The energy and co-volume parameters of PR EoS are modified by introducing a correction factor that is correlated as a function of reduced temperature. The results show that this model is capable of reproducing experimental saturated liquid density and vapor pressure data accurately.