Prediction of the PC-SAFT associating parameters by molecular simulation

Area of Science:

• Thermodynamics
• Chemical Engineering
• Computational Chemistry

Background:

• SAFT-type equations of state (EoS) are crucial for modeling fluids, especially those with hydrogen bonding.
• Accurate determination of association parameters (energy and volume) is essential for reliable EoS predictions.
• Current methods may not fully capture the complexities of hydrogen-bonding interactions in molecules like 1-alkanol.

Purpose of the Study:

• To develop a novel methodology for determining the association scheme and parameters of SAFT-type EoS.
• To apply this method to 1-alkanol systems and propose new parameters for the Perturbed Chain SAFT (PPC-SAFT) EoS.
• To validate the methodology by comparing simulation and experimental data.

Main Methods:

• Utilizing molecular simulation techniques to independently determine monomer and free hydrogen fractions.
• Deducing the most appropriate association scheme (identified as 3B for 1-alkanols).
• Back-calculating association strength from simulation results to use as an independent regression property for EoS parameters.

Main Results:

• The 3B association scheme was found to be most suitable for 1-alkanols.
• A new set of parameters for 1-alkanol in the PPC-SAFT EoS was derived using the proposed methodology.
• The developed parameters demonstrated good agreement with experimental data for phase properties and free hydrogen-bonding sites.

Conclusions:

• The new methodology enables accurate determination of association parameters for SAFT-type EoS.
• It allows for physically significant values of associating energy and volume.
• This approach enhances the predictive capability of EoS for hydrogen-bonding systems.