Effect of H2O Molecules on the CO2 Replacement in CH4 Hydrate Behavior by Molecular Simulation

CH4-CO2 replacement technology has broad application prospects in reducing CO2 emission and developing natural gas hydrate (NGH) resources. It is of great significance to study the mechanism of CH4-CO2 replacement. In this paper, the effect of H2O on CH4-CO2 displacement behavior is studied by molec...

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Bibliographic Details
Published in:Energy & Fuels
Main Authors: Yan, Ke-Feng, Chen, Hao, Chen, Zhao-Yang, Li, Xiao-Sen, Xu, Chun-Gang, Zhang, Yu, Xia, Zhi-Ming, Yu, Yi-Song
Format: Report
Language:English
Published: AMER CHEMICAL SOC 2021
Subjects:
CARBON-DIOXIDE SEQUESTRATION
GUEST-HOST INTERACTIONS
METHANE HYDRATE
GAS HYDRATE
DYNAMICS SIMULATION
CRYSTAL-GROWTH
INSIGHTS
MODEL
MICROMECHANISM
EQUILIBRIA
Energy & Fuels
Engineering
Chemical
Methane hydrate
Online Access:http://ir.giec.ac.cn/handle/344007/33286
http://ir.giec.ac.cn/handle/344007/33287
https://doi.org/10.1021/acs.energyfuels.1c00363
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Summary:CH4-CO2 replacement technology has broad application prospects in reducing CO2 emission and developing natural gas hydrate (NGH) resources. It is of great significance to study the mechanism of CH4-CO2 replacement. In this paper, the effect of H2O on CH4-CO2 displacement behavior is studied by molecular dynamics (MD) simulation and quantum mechanics calculation. The interactions between the host and guest in cages of CH4 hydrate are calculated using the symmetry-adapted perturbation theory method. The contribution of physical components of binding energy can be determined. The result indicates that the electrostatic interaction of H2O-H2O and H2O-gas is a key factor of the CH4-CO2 replacement mechanism. Additionally, the microconfigurations and microstructure properties are analyzed by MD simulation in the systems containing a gas layer (CO2 or CH4) and a CH4 hydrate layer. The results showed that the movement and the arrangement of H2O molecules influence the hydrate structure due to the interaction of H2O-gas during the replacement process. The molecular simulation suggests that the change of electrostatic interaction with H2O molecules could improve the CH4-CO2 replacement efficiency, which can be favorable for the investigation of CH4 replacement technology in NGH with CO2 injection.

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