SCI和EI收录∣中国化工学会会刊

Chinese Journal of Chemical Engineering ›› 2024, Vol. 69 ›› Issue (5): 79-91.DOI: 10.1016/j.cjche.2023.12.023

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Molecular simulation study on the evolution process of hydrate residual structures into hydrate

Liwei Cheng1,2,5, Yunfei Li1,5, Jinlong Cui2,3, Huibo Qin2,4, Fulong Ning1,5, Bei Liu2, Guangjin Chen2   

  1. 1. Faculty of Engineering, China University of Geosciences, Wuhan 430074, China;
    2. State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China;
    3. College of Science, Nanchang Institute of Technology, Nanchang 330099, China;
    4. School of Chemical Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, China;
    5. National Center for International Research on Deep Earth Drilling and Resource Development, China University of Geosciences (Wuhan), Wuhan 430074, China
  • Received:2023-09-29 Revised:2023-11-26 Online:2024-07-01 Published:2024-05-28
  • Contact: Liwei Cheng,E-mail:chengliwei@cug.edu.cn;Bei Liu,E-mail:liub@cup.edu.cn
  • Supported by:
    Financial support from the National Natural Science Foundation of China (22208329, 22178378, 22127812, 21908116 and U19B2005) and Jiangxi Provincial Natural Science Foundation of China (20232BAB213044) are gratefully acknowledged.

Molecular simulation study on the evolution process of hydrate residual structures into hydrate

Liwei Cheng1,2,5, Yunfei Li1,5, Jinlong Cui2,3, Huibo Qin2,4, Fulong Ning1,5, Bei Liu2, Guangjin Chen2   

  1. 1. Faculty of Engineering, China University of Geosciences, Wuhan 430074, China;
    2. State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China;
    3. College of Science, Nanchang Institute of Technology, Nanchang 330099, China;
    4. School of Chemical Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, China;
    5. National Center for International Research on Deep Earth Drilling and Resource Development, China University of Geosciences (Wuhan), Wuhan 430074, China
  • 通讯作者: Liwei Cheng,E-mail:chengliwei@cug.edu.cn;Bei Liu,E-mail:liub@cup.edu.cn
  • 基金资助:
    Financial support from the National Natural Science Foundation of China (22208329, 22178378, 22127812, 21908116 and U19B2005) and Jiangxi Provincial Natural Science Foundation of China (20232BAB213044) are gratefully acknowledged.

Abstract: The clathrate hydrate memory effect is a fascinating phenomenon with potential applications in carbon capture, utilization and storage (CCUS), gas separation, and gas storage as it can accelerate the secondary formation of clathrate hydrate. However, the underlying mechanism of this effect remains unclear. To gain a better understanding of the mechanism, we conducted molecular dynamic simulations to simulate the initial formation and reformation processes of methane hydrate. In this work, we showed the evolution process of hydrate residual structures into hydrate cages. The simulation results indicate that the residual structures are closely related to the existence of hydrate memory effect, and the higher the contribution of hydrate dissociated water to the hydrate nucleation process, the faster the hydrate nucleation. After hydrate dissociation, the locally ordered structures still exist after hydrate dissociation and can promote the formation of cluster structures, thus accelerating hydrate nucleation. Additionally, the nucleation process of hydrate and the formation process of clusters are inseparable. The size of clusters composed of cup-cage structures is critical for hydrate nucleation. The residence time at high temperature after hydrate decomposition will affect the strength of the hydrate memory effect. Our simulation results provide microscopic insights into the occurrence of the hydrate memory effect and shed light on the hydrate reformation process at the molecular scale.

Key words: Memory effect, Molecular simulation, Hydrate reformation, Residual structures

摘要: The clathrate hydrate memory effect is a fascinating phenomenon with potential applications in carbon capture, utilization and storage (CCUS), gas separation, and gas storage as it can accelerate the secondary formation of clathrate hydrate. However, the underlying mechanism of this effect remains unclear. To gain a better understanding of the mechanism, we conducted molecular dynamic simulations to simulate the initial formation and reformation processes of methane hydrate. In this work, we showed the evolution process of hydrate residual structures into hydrate cages. The simulation results indicate that the residual structures are closely related to the existence of hydrate memory effect, and the higher the contribution of hydrate dissociated water to the hydrate nucleation process, the faster the hydrate nucleation. After hydrate dissociation, the locally ordered structures still exist after hydrate dissociation and can promote the formation of cluster structures, thus accelerating hydrate nucleation. Additionally, the nucleation process of hydrate and the formation process of clusters are inseparable. The size of clusters composed of cup-cage structures is critical for hydrate nucleation. The residence time at high temperature after hydrate decomposition will affect the strength of the hydrate memory effect. Our simulation results provide microscopic insights into the occurrence of the hydrate memory effect and shed light on the hydrate reformation process at the molecular scale.

关键词: Memory effect, Molecular simulation, Hydrate reformation, Residual structures