CO2 sequestration trade-offs in polycrystalline hydrate stability

作者：Xinheng Li, Junde Huang, Kaibin Xiong, Yongxiao Qu, Xiaoyu Shi, Yuan Li, Zhisen Zhang, Jianyang Wu · 发表于：Carbon Neutrality · 年份：2025 · DOI：10.1007/s43979-025-00151-w · 被引用次数：9 · 研究领域：Methane Hydrates and Related Phenomena、CO2 Sequestration and Geologic Interactions、Carbon Dioxide Capture Technologies

Abstract Natural gas hydrates (NGHs) offer significant potential for energy recovery and carbon sequestration, yet the thermal stability of polycrystalline CH 4 -CO 2 hydrates (PCCHs) which is critical for CO 2 -based NGH exploitation, remains poorly understood. Here, we unravel CO 2 ’s role in reshaping the thermal dissociation behaviors of PCCHs via high-throughput molecular dynamics (MD) simulations and machine learning (ML). We demonstrate that CO 2 reduces the stability of PCCHs, with a 20% increase in CO 2 concentration lowering the melting point by approximately 6 K. Microstructural analysis reveals that this destabilization arises from CO 2 -induced distortion of 5 12 cage and formation of unconventional metastable cages. Thermal dissociation occurs via cage transformations and dissociations, where 4 1 5 10 6 2 and 5 12 6 2 cages act as hubs for solid–solid restructuring pathway. Crucially, CH 4 guest molecules facilitate simpler, faster cage transformations than CO 2 , which requires complex rearrangements. We further develop a GBDT ML model that accurately predicts PCCH melting points using microstructural information, identifying 5 12 , 5 12 6 2 , and 5 10 6 3 cages as key predictors. This model provides a practical tool for guiding CO 2 -based NGH exploitation and designing hydrate storage systems. These insights advance the molecular-level understanding of hydrate stability for CO 2 sequestration and NGH recovery. Graphical Abstract