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Development of the Transferable Potentials for Phase Equilibria Model for Hydrogen Sulfide
Mansi S Shah1, Michael Tsapatsis1, J Ilja Siepmann1
1†Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, Minnesota 55455-0132, United States.
The Journal of Physical Chemistry. B
|May 19, 2015
Summary
This study extends transferable potentials for phase equilibria force fields to hydrogen sulfide. Optimized models accurately predict vapor-liquid equilibria and condensed-phase properties, crucial for chemical process simulations.
Area of Science:
- Physical Chemistry
- Computational Chemistry
- Chemical Engineering
Background:
- Developing accurate force fields for molecular simulations is essential for predicting chemical behavior.
- Hydrogen sulfide (H2S) is a key component in natural gas and industrial processes, requiring precise modeling.
- Existing transferable potentials need validation and extension for molecules like H2S.
Purpose of the Study:
- To extend transferable potentials for phase equilibria force fields to hydrogen sulfide.
- To develop accurate molecular models for H2S by parametrizing Lennard-Jones and Coulomb interactions.
- To evaluate different site models for H2S in predicting its thermodynamic and structural properties.
Main Methods:
- Parametrization of Lennard-Jones (LJ) and Coulomb interactions using pure-component and binary vapor-liquid equilibria (VLE) data for H2S with methane and carbon dioxide.
- Consideration of three-site and four-site molecular models for H2S, varying charge placement and LJ site locations.
- Assessment of model performance using liquid-phase relative permittivity, liquid-phase structure, solid-phase lattice parameters, relative permittivity, and triple point data.
Main Results:
- Four distinct models were developed, with three-site models accurately reproducing all parametrization properties.
- Two optimized three-site models were further evaluated for condensed-phase properties and phase equilibria.
- An effective balance between LJ interactions and electrostatic terms (dipolar, quadrupolar) was achieved for a four-site model, yielding high accuracy.
Conclusions:
- Transferable potentials for phase equilibria force fields can be successfully extended to hydrogen sulfide.
- Three-site models with specific LJ site arrangements demonstrate high accuracy in predicting H2S properties.
- Optimized models provide reliable predictions for condensed-phase behavior and phase equilibria of hydrogen sulfide.
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