Development of the Transferable Potentials for Phase Equilibria Model for Hydrogen Sulfide

Abstract

The transferable potentials for phase equilibria force field is extended to hydrogen sulfide. The pure-component and binary vapor-liquid equilibria with methane and carbon dioxide and the liquid-phase relative permittivity are used for the parametrization of the Lennard-Jones (LJ) and Coulomb interactions, and models with three and four interaction sites are considered. For the three-site models, partial point charges are placed on the sites representing the three atoms, while the negative partial charge is moved to an off-atom site for the four-site models. The effect of molecular shape is probed using either only a single LJ interaction site on the sulfur atom or adding sites also on the hydrogen atoms. This procedure results in four distinct models, but only those with three LJ sites can accurately reproduce all properties considered for the parametrization. These two are further assessed for predictions of the liquid-phase structure, the lattice parameters and relative permittivity for the face-centered-cubic solid, and the triple point. An effective balance between LJ interactions and the dipolar and quadrupolar terms of the first-order electrostatic interactions is struck in order to obtain a four-site model that describes the condensed-phase properties and the phase equilibria with high accuracy.

Chemical potentials of water, methanol, carbon dioxide and hydrogen sulphide at low temperatures using continuous fractional component Gibbs ensemble Monte Carlo

“…For carbon dioxide, TraPPE force field parameters were used [38]. Details about the force field parameters, truncation of intermolecular potentials, and tail corrections are provided in the Supporting Information.…”

“…To identify the underlying reason and criterion for the limitations of the WTPI method, we have chosen to simulate the VLE of four different components in the GE with similar coexistence liquid densities, namely water and methanol (with a hydrogen bonding network), and hydrogen sulphide and carbon dioxide (without a hydrogen bonding network). To study the role of different models, we have used several force fields for water and methanol: SPC, [32] TIP3P-EW [33], TIP4P-EW [34] and TIP5P-EW [35]) water, OPLS and TraPPE methanol [36,37], hydrogen sulphide [38] and TraPPE carbon dioxide [39].…”

Correlations for the Dielectric Constants of $$\hbox {H}_{2}\hbox {S}$$ H 2 S , $$\hbox {SO}_{2}$$ SO 2 , and $$\hbox {SF}_{6}$$ SF 6

“…For H 2 S, the 4-3 model of Shah et al [17] is used. The model contains three atomic sites and an “X” site located on the bisector of the H-S-H angle.…”

“…The S-O separation is 1.432 Å and the O-S-O angle is 119.3°. The charges and Lennard-Jones parameters are listed in the references [17, 18]. The Lennard-Jones parameters between unlike sites are determined with the Lorentz-Berthelot combining rules [19].…”

Identifying Optimal Zeolitic Sorbents for Sweetening of Highly Sour Natural Gas

“…Foradsorptive separations,one of the main challenges for selective H 2 Sr emoval from sour gas is the presence of H 2 Ovapor because H 2 O, with its higher dipole,h as ah igher affinity for strong adsorption sites. Advances in efficient Monte Carlo algorithms [15,16] and accurate force fields [17,18] have enabled predictive modeling of phase and sorption equilibria. [3][4][5] Siliceous zeolites (high Si/Al ratio) containing only minute quantities of polar cations and silanol defects are very hydrophobic, [6] and offer an opportunity to selectively capture H 2 Sfrom moist natural gas.…”