The Effect of Binary Interaction Parameters and Induced Association on the Performance of the PC-SAFT Equation of State: Validation against a Benchmark Database of High-Quality Binary-System Data

Abstract

The performance of the Perturbed Chain - Statistical Associating Fluid Theory (PC-SAFT) equation of state (EoS) using classical mixing rules, induced-association schemes for mixtures exhibiting cross-association phenomena between two components that do not self-associate, and one regressed temperature-independent binary interaction parameter (k ij ) per mixture is assessed using a high-quality reference database containing binary-system data for various properties. The binary mixtures that are included in the database are divided into nine categories (Binary Association Codes, BACs) according to their ability to be involved in a hydrogen bond. Grading of the EoS is done by applying an already published procedure with certain modifications that were also published recently. An important feature is the inclusion of a performance indicator, called the “Success Ratio” (SR), that quantifies the percentage of experimental data points which the model can qualitatively reproduce. The original marks of the PC-SAFT EoS when implemented with classical mixing rules, no induced-association scheme, and a k ij parameter set equal to zero are recalculated with the modified grading procedure and are directly compared with the new marks obtained in this work. The effect of including induced-association effects in PC-SAFT for mixtures that belong to BAC6, BAC7, and BAC8 (mixtures in which cross-association takes place without both components being self-associating) is also investigated. The effect of regressing cross-association parameters vs regressing k ij parameters for mixtures belonging to the BAC6 group (mixtures in which cross-association arises although the two components do not self-associate) is showcased. The final optimized PC-SAFT EoS utilizes classical mixing rules, induced-association effects (using regressed cross-association parameters for some binary systems belonging to BAC6 and a predictive method for BAC7 and BAC8), and one temperature-independent k ij parameter per binary mixture (except for binary systems belonging to BAC6 for which cross-association parameters were adjusted). The final average mark of the optimized EoS is 9.3/20.

Modeling Mixtures with PCP-SAFT: Insights from Large-Scale Parametrization and Group-Contribution Method for Binary Interaction Parameters

“…If this interaction is not accounted for explicitly in the equation of state, the only remedy is a large negative binary interaction parameter k ij . However, the association contribution in SAFT models is fully capable of capturing this effect of so-called induced association [28][29][30][31][32].…”

“…Although not explicitly considered by Wertheim initially, the framework is flexible enough to capture the so-called induced association between molecules [28]. Including the induced association in the model significantly improves the description of binary mixtures as shown by Cripwell et al [29], Marshall and Bokis [30], and more recently by Nikolaidis et al [31] and Smith et al [32].…”

“…In a recent study, Esper et al [43] published pure-component PCP-SAFT parameters for 1842 substances. When it comes to assessing mixture properties, Nikolaidis et al [31,44] investigated the performance of PC-SAFT on a set of 200 representative binary mixtures [45]. However, a comprehensive parametrization based on a large amount of experimental data that also accounts for the intricacies of hydrogen bonding, including induced association, is still lacking.…”

PCP-SAFT Parameters of Pure Substances Using Large Experimental Databases

“…This question cannot be answered solely by examining pure substance data, as the missing (yet physically motivated) contributions can be compensated for by adjusting the hard-chain and dispersive parameters for pure substances. Neglecting association contributions to the Helmholz energy proves problematic when considering mixtures, as demonstrated by Nikolaidis et al , …”

Thermodynamic Properties of Binary Mixtures Containing Ionic Liquid 1-Butyl-3-methylimidazolium Thiocyanate and Ethanolamines at Different Temperatures: Measurement and PC-SAFT Modeling

“…Chemical engineering requires precise thermodynamic data and calculations for different purposes such as process design, and it means using the equation of state as one of the most important tools in thermodynamic would be necessary for calculations and modeling. − Accordingly, selecting the proper equation of state is crucial for chemical engineering purposes between the numerous models. − On the other hand, statistical mechanics includes equation of states that uses microscopic information from quantum mechanics of a certain system, processes it, and calculates macroscopic measurable variables. − One of the most successful equations of states is Perturbation chain- statistical associated fluid theory (PC-SAFT) that has been applied for modeling of the mixture’s thermodynamic properties. − A molecule is assumed as a hard chain consisting of hard spheres in PC-SAFT by imposing first- and second-order thermodynamic perturbations. , Also, different terms have been added to extend the model for different varieties of the molecules. − …”