Modeling Hydrofluoroolefins with the Cubic Plus Association and Perturbed-Chain Statistical Associating Fluid Theory Equations of State

Abstract

Hydrofluoroolefins (HFOs) have been proposed as promising candidates for alternative refrigerants. In this work, a comprehensive comparison of the performance of the Cubic Plus Association (CPA) and (perturbed-chain statistical associating fluid theory) (PC-SAFT) equations of state for six thermodynamic properties of HFOs is presented, in which 11 parameter estimation methods are considered and analyzed. On the basis of the comparison with experimental data and a theoretical analysis, a method meeting both satisfactory results and simplicity is recommended for parameter estimation for this type of compounds. The results show that both CPA and PC-SAFT perform equally well for the prediction of vapor pressure, liquid density, and speed of sound in the gas phase. CPA provides better isobaric heat capacity predictions compared to PC-SAFT irrespectively of the estimation method used, but PC-SAFT presents the best overall performance when all properties are considered.

Implementation of CP-PC-SAFT and CS-SAFT-VR-Mie for Predicting Thermodynamic Properties of C1–C3 Halocarbon Systems. I. Pure Compounds and Mixtures with Nonassociating Compounds

“…At the same time, other studies − have demonstrated accurate modeling of halocarbon systems using various Cubic and SAFT-type EoSs while neglecting such interactions. In this respect, a very important investigation was recently made by Kang et al These authors have performed a fundamental comparison of PC-SAFT and Cubic-Plus-Association (CPA) models, while fitting their parameters to various databases covering different thermodynamic properties of hydrofluoroolefins. They have concluded that although addition of the association term improves modeling of heat capacities, it deteriorates accuracy in estimating other properties.…”

Evaluation of Liquid Heat Capacity of Latest Low Global Warming Hydrofluoroolefins (HFOs): A Comparison of a Cubic Equation of State, Fundamental Equations of State, and a Corresponding State Equation

“…In recent years, novel EOS such as perturbation EOS (such as PC-SAFT) and cubic plus association EOS (CPA) have also been proposed for alternative refrigerants R1233zd(E), R1234yf, R1234ze(E), and R1234ze(Z) [18]. PC-SAFT is Helmholtz free energy-based and its calculation for isobaric heat capacity follows the same process with FEOS, while CPA is pressure-based, adding an association part to traditional cubic EOS.…”

Application of Quantum Chemistry Insights to the Prediction of Phase Equilibria in Associating Systems

“…A general approach to address the degenerate parameter problem is to include one or more properties in addition to saturated liquid density and vapor pressure data for parameter estimation. Thermodynamic properties such as speed of sound, second virial coefficient, enthalpy of vaporization, and heat capacity can be included when parameterizing both nonassociating and associating systems. , Practical challenges with this approach include the availability of experimental data as well as assigning weights to each additional property in the objective function. Strategies are available to guide the optimal selection of weights (Pareto optimal solutions visualized on a Pareto front), but these techniques have not yet been widely applied to parameterizing thermodynamic models. , …”