Molecular Dynamics Simulation of the Three-Phase Equilibrium Line of CO 2 Hydrate with OPC Water Model

The three-phase coexistence line of the CO2 hydrate was determined using molecular dynamics (MD) simulations. By using the classical and modified Lorentz-Berthelot (LB) parameters, the simulations were carried out at 10 different pressures from 3 to 500 MPa. For the OPC water model, simulations with...

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Bibliographic Details
Published in:ACS Omega
Main Authors: Hao, Xiluo, Li, Chengfeng, Meng, Qingguo, Sun, Jianye, Huang, Li, Bu, Qingtao, Li, Congying
Format: Report
Language:English
Published: AMER CHEMICAL SOC 2023
Subjects:
Chemistry
Multidisciplinary
METHANE HYDRATE
CARBON-DIOXIDE
PHASE-EQUILIBRIUM
GAS HYDRATE
NUCLEATION
GROWTH
ETHYLENE
Berthelot
Methane hydrate
Online Access:http://ir.qdio.ac.cn/handle/337002/181546
http://ir.qdio.ac.cn/handle/337002/181547
https://doi.org/10.1021/acsomega.3c05673
Description
Summary:The three-phase coexistence line of the CO2 hydrate was determined using molecular dynamics (MD) simulations. By using the classical and modified Lorentz-Berthelot (LB) parameters, the simulations were carried out at 10 different pressures from 3 to 500 MPa. For the OPC water model, simulations with the classic and the modified LB parameters both showed negative deviations from the experimental values. For the TIP4P/Ice water model, good agreement with experimental equilibrium data can be achieved when the LB parameter is adjusted based on the solubility of CO2 in water. Our results also show that the influence of the water model on the equilibrium prediction is much larger than the CO2 model. Current simulations indicated that the H2O-H2O and H2O-CO2 cross-interactions' parameters might contribute equally to the accurate prediction of T-3. According to our simulations, the prediction of T-3 values showed relatively higher accuracy while using the combination of TIP4P/Ice water and EPM2 CO2 with modified LB parameter. Furthermore, varied chi values are recommended for accurate T-3 estimation over a wide pressure range. The knowledge obtained in this study will be helpful for further accurate MD simulation of the process of CO2/CH4 replacement.

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