Unraveling nucleation pathway in methane clathrate formation

Liwen Li, Jie Zhong, Youguo Yan, Jun Zhang, Jiafang Xu, Joseph S. Francisco, Xiao Cheng Zeng

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Methane clathrates are widespread on the ocean floor of the Earth. A better understanding of methane clathrate formation has important implications for natural-gas exploitation, storage, and transportation. A key step toward understanding clathrate formation is hydrate nucleation, which has been suggested to involve multiple evolution pathways. Herein, a unique nucleation/growth pathway for methane clathrate formation has been identified by analyzing the trajectories of large-scale molecular dynamics (MD) simulations. In particular, ternary water-ring aggregations (TWRAs) have been identified as fundamental structures for characterizing the nucleation pathway. Based on this nucleation pathway, the critical nucleus size and nucleation timescale can be quantitatively determined. Specifically, a methane hydration layer compression/shedding process is observed to be the critical step in (and driving) the nucleation/ growth pathway, which is manifested through overlapping/ compression of the surrounding hydration layers of the methane molecules, followed by detachment (shedding) of the hydration layer. As such, an effective way to control methane hydrate nucleation is to alter the hydration layer compression/shedding process during the course of nucleation.

Original languageEnglish (US)
Pages (from-to)24701-24708
Number of pages8
JournalProceedings of the National Academy of Sciences of the United States of America
Volume117
Issue number40
DOIs
StatePublished - Oct 6 2020

Keywords

  • Aggregations
  • Clathrate
  • Methane
  • Nucleation

ASJC Scopus subject areas

  • General

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