Group-contribution SAFT equations of state: A review

Self Cite

Replacement of aqueous alkanolamine-based carbon capture fluids with nonaqueous alternatives may be a promising route to reduce the energy requirements of current postcombustion carbon capture processes. In line with this, the s-SAFT-γ Mie predictive group contribution Equation of State is developed toward a description of the thermodynamic properties of nonaqueous alkanolamine-based carbon capture systems in this work. A consistent and systematic methodology is used to develop s-SAFT-γ Mie group interaction parameters required for modeling these systems. This entails extending the model to the primary amine (CH 2 NH 2 /NH 2 ) and secondary alcohol (CHOH) groups, as well as their interactions with the n-alkane (CH 2 and CH 3 ) and primary alcohol (CH 2 OH/OH) groups. Parameters were also developed for the interactions of CO 2 with the n-alkane, primary alcohol, and secondary alcohol groups, respectively. The model, with its active parameter sets, generally provides a robust description of the phase equilibria of the systems considered. This renders the developed parameters suitable for expanding the model to ternary-component alkanolamine-based nonaqueous carbon capture systems in further work.

Section: Introductionmentioning

confidence: 99%

Toward Nonaqueous Alkanolamine-Based Carbon Capture Systems: Parameterizing Amines, Secondary Alcohols, and Carbon Dioxide-Containing Systems in s-SAFT-γ Mie

Schulze-Hulbe,

Shaahmadi,

Burger

et al. 2023

Self Cite

“…42 However, these data are lacking for the majority of substances in biofuels, making it difficult to obtain accurate and complete component parameters, which would introduce error in predicting results. Therefore, the group contribution (GC) method 45 has been proposed as an ingenious way to calculate the necessary parameters. This method assumes that each functional group within the molecules imparts a contribution to the overall parameter values of the pure component.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Modeling Investigations of Density and Viscosity for the Ternary (N-Octane + Ethylcyclohexane + Ethylbenzene) Mixtures

Li,

Qin,

Wang

et al. 2024

Biofuels are increasingly recognized as the most practical way to reduce carbon dioxide emissions and pollution in the transport industry. However, the production and promotion of biofuels have encountered many obstacles due to their complex composition and the ambiguity in studies on the physicochemical properties. To achieve a thorough comprehension of biofuel density and viscosity properties, developing suitable surrogate mixtures is an accurate and efficient method. N-Octane, ethylcyclohexane, and ethylbenzene are important components of biofuel surrogate mixtures to reflect the thermophysical properties of three primary hydrocarbons (alkanes, cycloalkanes, and alkylbenzenes). Therefore, the liquid density and viscosity of ternary mixtures (n-octane + ethylcyclohexane + ethylbenzene) are measured using a vibrating-tube densimeter and vibrating-wire viscometer, respectively, over the temperature range from 283.15 to 363.15 K and at pressures of up to 60 MPa. Moreover, the excess volume and viscosity deviations of the mixtures were obtained. For density, the group contribution (GC) PC-statistical associating fluid theory (PC-SAFT) equation of state (EoS) and SAFT-γ Mie EoS have been compared to assess the effect of different interaction potential functions on the prediction of liquid-phase densities. The results showed that the SAFT-γ Mie EoS gave the best prediction, followed by the GC PC-SAFT EoS. In terms of viscosity, a new mapping law for effective molecular weight has been developed to improve the predictive accuracy of the 1-cEHS model, and the absolute average deviations (AAD%) are 3.3− 5%. In addition, excess molar volumes and viscosity deviations in this work are derived and discussed to further explore the influence of different molecular structures on thermophysical properties.

“…The Statistical Association Fluid Theory (SAFT) equation of state (EoS), in its many forms, has been successfully used to describe the properties of many fluids and their mixtures. − At its core, the SAFT EoS describes the interactions between molecules with an explicit potential, which enables a higher reliability than other equations of state. The use of a group contribution EoS, such as SAFT-γ-Mie, conveys an easy way to obtain transferable coarse-grained force fields for molecular simulations based on an accurate description of thermophysical properties.…”

Section: Introductionmentioning

confidence: 99%

Using the SAFT-γ-Mie to Generate Coarse-Grained Force Fields Useable in Molecular Dynamics Simulations: Describing the Micellar Phases of Polyalkylglycols in Aqueous Solutions

Silva

Pérez‐Sánchez

Pantano

et al. 2023

In this work, we showcase the potential of the SAFT-γ-Mie equation of state to obtain, in a top-down approach, coarse-grained molecular models capable of describing micellization phenomena. For this purpose, we selected polyethylene oxide (PEO)/polypropylene oxide (PPO) triblock copolymers in aqueous solutions as a case study. The model was fitted to reproduce the thermophysical properties�liquid densities and vapor pressures�of small PEO/PPO oligomers as well as the activity coefficients or liquid−liquid phase diagrams of their binary mixtures with water. At low concentrations, the MD simulations show the formation of spherical micelles of morphology comparable to experiments, with the characteristic star-shaped or flower-shaped morphology depending on the polymer block sequence. The local structure and molecular conformations were analyzed, showing distinctions between the two types of aggregates. At higher concentrations, depending on the co-polymer sequence, the molecules form larger micelles or coalesce into larger aggregates when signs of phase separation are observed, as expected.