RT Journal Article
T1 Three phase equilibria of the methane hydrate in NaCl solutions: A simulation study
A1 Blázquez Fernández, Samuel
A1 Vega De Las Heras, Carlos
A1 Conde, María
AB Molecular dynamics simulations have been performed to determine the three-phase coexistence temperature for a methane hydrate system in equilibrium with a NaCl solution and a methane gas phase. The direct coexistence technique is used following two approaches, one where the triple coexistence temperature for a given NaCl concentration is narrow down and another where the concentration at a given temperature is equilibrated. In both approaches the results are consistent within the error bars. All simulations were carried out at 400 bar and the range of concentrations explored extends up to a molality of 4 m. TIP4P/2005 for water molecules and a simple Lennard-Jones interaction site for methane were used to simulate the system. Positive deviations from the Lorentz-Berthelot energetic rule have been applied between methane and water (i.e., increasing the attractive interaction between water and methane). Na+ and Cl− ions were described by using the Madrid-2019 scaled charge model. The role played by finite size effects in the calculation of the coexistence line was analyzed by studying a system with larger number of molecules at a given NaCl concentration. Overall, our simulations show that upon NaCl addition to the liquid water phase, a shift in the three-phase equilibrium line to lower temperatures is produced as occurs in the ice-NaCl(aq) system. The depression of the three-phase coexistence line obtained at different concentrations is in a very good agreement with the experimental results.
SN 0167-7322
YR 2023
FD 2023
LK https://hdl.handle.net/20.500.14352/95344
UL https://hdl.handle.net/20.500.14352/95344
LA eng
NO Blazquez, S., et al. «Three Phase Equilibria of the Methane Hydrate in NaCl Solutions: A Simulation Study». Journal of Molecular Liquids, vol. 383, agosto de 2023, p. 122031. https://doi.org/10.1016/j.molliq.2023.122031.
DS Docta Complutense
RD 28 abr 2025