气候变化领域集成服务门户(CCPortal): Reduced phase stability and faster formation/dissociation kinetics in confined methane hydrate

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DOI	10.1073/pnas.2024025118
	Reduced phase stability and faster formation/dissociation kinetics in confined methane hydrate
	Jin D.; Coasne B.
发表日期	2021
ISSN	00278424
卷号	118 期号:16
英文摘要	The mechanisms involved in the formation/dissociation of methane hydrate confined at the nanometer scale are unraveled using advanced molecular modeling techniques combined with a mesoscale thermodynamic approach. Using atom-scale simulations probing coexistence upon confinement and free energy calculations, phase stability of confined methane hydrate is shown to be restricted to a narrower temperature and pressure domain than its bulk counterpart. The melting point depression at a given pressure, which is consistent with available experimental data, is shown to be quantitatively described using the Gibbs-Thomson formalism if used with accurate estimates for the pore/liquid and pore/hydrate interfacial tensions. The metastability barrier upon hydrate formation and dissociation is found to decrease upon confinement, therefore providing a molecular-scale picture for the faster kinetics observed in experiments on confined gas hydrates. By considering different formation mechanisms-bulk homogeneous nucleation, external surface nucleation, and confined nucleation within the porosity-we identify a cross-over in the nucleation process; the critical nucleus formed in the pore corresponds either to a hemispherical cap or to a bridge nucleus depending on temperature, contact angle, and pore size. Using the classical nucleation theory, for both mechanisms, the typical induction time is shown to scale with the pore volume to surface ratio and hence the pore size. These findings for the critical nucleus and nucleation rate associated with such complex transitions provide a means to rationalize and predict methane hydrate formation in any porous media from simple thermodynamic data. © 2021 National Academy of Sciences. All rights reserved.
英文关键词	Confinement; Formation/dissociation kinetics; Gas hydrate; Molecular modeling; Porous media
语种	英语
scopus关键词	article; contact angle; dissociation; hydration; molecular model; pore size; pore volume; porosity
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/179823
作者单位	University Grenoble Alpes, CNRS, LIPhy, Grenoble, 38000, France
推荐引用方式 GB/T 7714	Jin D.,Coasne B.. Reduced phase stability and faster formation/dissociation kinetics in confined methane hydrate[J],2021,118(16).
APA	Jin D.,&Coasne B..(2021).Reduced phase stability and faster formation/dissociation kinetics in confined methane hydrate.Proceedings of the National Academy of Sciences of the United States of America,118(16).
MLA	Jin D.,et al."Reduced phase stability and faster formation/dissociation kinetics in confined methane hydrate".Proceedings of the National Academy of Sciences of the United States of America 118.16(2021).