Vol.:(0123456789) International Journal of Thermophysics (2020) 41:11 https://doi.org/10.1007/s10765-019-2588-z 1 3 Analysis of Thermodynamic Consistency Behavior of CO 2 Solubility in Some Associating Solvents Milad Mashayekhi 1  · Hossein Sakhaeinia 1  · Mohammad Shokouhi 2 Received: 3 April 2019 / Accepted: 10 December 2019 © Springer Science+Business Media, LLC, part of Springer Nature 2020 Abstract The thermodynamic consistency analysis of ten mixtures of CO 2 /associating sol- vents with total of 160 isothermal data sets was investigated. For this purpose, the area test based on the generalized Gibbs–Duhem equations was applied and the Peng and Robinson/Stryjek and Vera equation of state with Panagiotopoulos–Reid com- bining rule (PRSV/PR EoS) was employed to correlate the isothermal P–T–x data. The binary adjustable constants in PRSV/PR EoS were fgured out by optimization of errors on pressure and defned area simultaneously as an objective function in bubble pressure algorithm. The results turn out that among 160 isotherms meaning- fully investigated, 29 data sets were found to be thermodynamically consistent, 72 data sets were found to be not fully consistent, 55 data sets were found to be thermo- dynamically inconsistent, and 4 data sets were found to be tried with other models. Keywords Carbon dioxide · Equation of state · Gibbs–Duhem equation · Thermodynamic consistency · Thermodynamics modeling List of symbols Variables  1i Characteristic pure compound parameter in PRSV EoS R Universal gas constant k ij and k ji First and second binary interaction parameters l ij Third adjustable parameter υ Molar volume  r Residual molar volume H r Residual molar enthalpy * Hossein Sakhaeinia h.sakhaeinia@iauctb.ac.ir 1 Department of Chemical Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran 2 Gas Science Department, Gas Research Division, Research Institute of Petroleum Industry (RIPI), National Iranian Oil Company (NIOC), Tehran, Iran