Work

Evaluation of thermodynamic models for the prediction of derivative properties for non-polar compounds

Year: 2025

Type: article

Abstract: • The performance of SRK, PR, CPA, CK-SAFT, PC-SAFT, SAFT-VR Mie, SAFT-γ Mie, and GERG-2008 models on predicting first and second-order derivative properties of non-polar compounds is studied. • GERG-2008 provides overall the most accurate description of the properties studied, while SAFT-VR Mie and SAFT-γ Mie present the best performance among general models. • Parameterization plays an important role, while the description of intrinsic molecular interactions shows a more important role in their performance, especially for predicting second-order derivative thermodynamic properties. • The analysis on dP/dV and dP/dT , second-order helmholtz derivatives, and the separate contributions shows significant intrinsic differences among the general models. Thermodynamic models have been developed for many decades, while a persistent challenge remains in identifying the most effective model for specific systems. In this study, a wide range of thermodynamic models, including SRK, PR, CPA, CK-SAFT, PC-SAFT, SAFT-VR Mie, SAFT-γ Mie, and GERG-2008, have been analyzed to evaluate their performance in predicting the first- and second-order derivative properties of compounds such as alkanes, N₂, and CO₂. Properties such as saturation pressure, liquid density, isobaric and isochoric heat capacities including their residual terms, speed of sound, and Joule-Thomson coefficient have been examined. While GERG-2008, as a multiparameter equation of state consistently outperforms other models across most properties, among general thermodynamic models, SAFT-VR Mie and SAFT-γ Mie have demonstrated superior performance over conventional cubic models, particularly in predicting second-order derivative properties, and PC-SAFT has shown superior results for isobaric heat capacity and Joule-Thomson coefficient. To gain deeper insights into the results, further examination of the model's performance in predicting selected second-order derivative properties ( dP/dT, dP/dV , ( ∂ 2 A res / ∂ V 2 ) T , n , ( ∂ 2 A res / ∂ T ∂ V ) n , and ( ∂ 2 A res / ∂ T 2 ) V , n ) has been conducted. Additionally, the contributions of hard-sphere, chain, and dispersion terms to the second-order derivatives of Helmholtz energy have been analyzed, highlighting the significant impact of these terms on volume and temperature derivatives. This manuscript also discusses possible challenges and potential improvements in these models' predictive capabilities.

Source: Fluid Phase Equilibria

DOI: 10.1016/j.fluid.2025.114366

Authors: Javad Amanabadi, Georgios M. Kontogeorgis, Xiaodong Liang

Institution: Technical University of Denmark

Language: English

Topic: Phase Equilibria and Thermodynamics

Subfield: Biomedical Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,630

Funder: Danmarks Frie Forskningsfond