冰点下多孔介质中甲烷水合物的生成特性
Formation Behaviors of Methane Hydrate in Porous Media below Freezing Point

摘要： 冰点下水合物在多孔介质的生成是一个复杂的多相转化过程，为了研究冰点下多孔介质中水合物生成过程的水相转化率、气体消耗量与稳定压力等生成特性，在定容条件下，进行不同孔径与粒径的多孔介质中甲烷水合物在冰点下的生成实验。所使用的多孔介质平均孔径为1295 nm、1796 nm和3320 nm。研究结果表明：水合物生成结束时水的转化率随着初始生成压力的增大而增大，随着温度的升高而降低，随着孔径的增大而增大；在相同的孔径下，多孔介质粒径的增大降低了水合物的生成速率但对最终气体消耗量没有影响；在相同的温度下，随着初始生成压力的增大，实验最终压力、气体消耗量与最终水的转化率均随之升高；温度越高，不同的生成初始生成压力下体系的最终稳定压力与水的转化率相差越大；在多孔介质的毛细管作用力与结合水的共同作用下，冰点下水合物生成的水的转化率会大大地降低。在本实验条件下，水相转化为水合物的比例最高为32.39%。
Abstract: The hydrate formation in porous media below freezing point is a complicated multiphase transition process, including water, ice, hydrate and bound water. In order to study the formation behaviors of methane hydrate in porous media below freezing point, such as water conversion, gas consumption and stable conditions, the formation experiments of methane hydrate in porous media were carried out. The silica gels with the mean pore diameters of 1295 nm, 1796 nm and 3320 nm were used as the porous media for the experiments. The experimental results indicate that the water conversion in the porous media after the hydrate formation increases with the increase of the initial formation pressure, the decrease of the bath temperature and the increase of the mean pore diameter. The particle size of the porous media reduces the formation rate of the hydrate but has a slight effect on the final gas consumption. At the same experimental temperature, the system pressure after the hydrate formation, the final gas consumption and the final water conversion increase with the increase of the initial formation pressure. The differences of final system pressure and water conversion in the different initial pressure experiments increase with the formation temperature. Due to the effect of the capillary force and the bound water in porous media, the water conversion of the hydrate formation significantly becomes lower. At the experimental conditions in this study, the highest water conversion is up to 32.39%