Natural gas hydrates are mainly stored in the pores of the sedimentary layer in permafrost regions, and the formation characters in porous media were particularly important for the exploitation and utilization of natural gas hydrates. So, it is essential to understand the formation process of methane hydrate in porous media below freezing point. In this study, the formation process of methane hydrate was studied in a closed system in porous media below freezing point. The results indicated that the initial pressure played an important role in the formation characteristics of methane hydrate in porous media below freezing point. The higher the initial pressure was, the larger the formation rate of methane hydrate. And the maximum formation rate attained 6.46 × 10⁻⁴ mol/h when the initial pressure was 9.0 MPa under the same temperature and particle size conditions. Furthermore, the final conversion rate was larger at higher initial pressure and the final conversion rate attained 56.5% at an initial pressure of 9.0 MPa. Furthermore, the pressure disturbance could improve the formation process of methane hydrate and the final conversion rate was larger to some extent. The relevant results will provide a theoretical reference for natural gas hydrates exploitation.

中文翻译：

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压力对冰点以下多孔介质中CH4水合物形成过程的影响

天然气水合物主要储存在多年冻土区沉积层孔隙中，​​多孔介质中的形成特征对天然气水合物的开发利用尤为重要。因此，了解冰点以下多孔介质中甲烷水合物的形成过程至关重要。本研究在低于冰点的多孔介质中，在封闭系统中研究了甲烷水合物的形成过程。结果表明，初始压力对冰点以下多孔介质中甲烷水合物的形成特征有重要影响。初始压力越高，甲烷水合物的生成速率越大。并且最大形成速率达到6.46 × 10 ^-4 在相同温度和粒径条件下，初始压力为 9.0 MPa 时的 mol/h。此外，在较高的初始压力下，最终转化率更大，在 9.0 MPa 的初始压力下，最终转化率达到 56.5%。此外，压力扰动可以改善甲烷水合物的形成过程，最终转化率在一定程度上更大。相关结果将为天然气水合物的开发提供理论参考。