权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

EXPERIMENTAL STUDY OF METHANE HYDRATE FORMATION AND DECONPOSITION IN FROZEN SOILS

冻土中甲烷水合物形成与分解的实验研究

基本信息

批准号：
07680597
负责人：
ISHIZAKI Takeshi
金额：
$ 1.41万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07680597/
关键词：
Methane hydrate Permafrost Formation and Decomposition Unfrozen Water Ice Segregation Natural Gas 永晶析出エネルギー

项目摘要

The experiments were performed to study methane hydrate formation and decomposition in frozen soil. The samples used here are silicate sand, bentonite clay and porous glass powders. Two types of porous glass powders whose pore diameters are 50nm and 10nm are used. The samples were prepared under water saturated condition or unsaturated condition. In the latter case, only inside of pores are saturated with water. It means that water is highly bound in side of small capillary tubes. The experimental procedures are follows : First sample were put inside the pressure cell. The air contained in the cell was removed with vacuums pumpand pressurized methane was put in the cell. Then the temperature of sample was lowered below 0ﾟC to form methane hydrate inside the sample. After the methane hydrate formation was completed, the temperature of the sample was warmed up at a constant warming speed to decompose the methane hydrate. During the experiment, the temperature of sample and pressure of cell ware monitored. The relationship between pressure and temperature was compared with the phase equilibrium of methane hydrate in pure water without soil. The P-T curves of methane hydrate decomposition in water saturated soil sample are coincided well with the P-T curve of methane hydrate decomposition in pure water. This can be explained by that free water is available under the water saturated condition. The P-T curve of methane hydrate decomposition in unsaturated condition shifted toward low temperature and high pressure region. At the pressure of 6 MPa, the decompose temperature was lower than that in pure water by 1.2 K for 50 nm pore size sample and 6 K for 10nm pore size sample. This result is due to that fact that the pore water is highly bound in side of small capillary tubes. These data were compared with the data of unfrozen water content obtained by NMR technique.

对冻土中甲烷水合物的生成和分解进行了实验研究。这里使用的样品是硅酸盐砂、膨润土和多孔玻璃粉。采用了孔径为50 nm和10 nm的两种类型的多孔玻璃粉。在水饱和和非饱和条件下制备样品。在后一种情况下，只有孔隙内部被水饱和。这意味着水高度结合在小毛细管的一侧。实验步骤如下：首先将样品放入压力池中。用真空泵抽除池中的空气，并向池中加入加压甲烷。然后将样品的温度降低到0 ℃以下，以在样品内部形成甲烷水合物。在甲烷水合物形成完成之后，以恒定升温速度升温样品的温度以分解甲烷水合物。在实验过程中，对样品温度和电池压力进行了监测。将压力-温度关系与甲烷水合物在无土纯水中的相平衡进行了比较。饱和土样中甲烷水合物分解的P-T曲线与纯水中甲烷水合物分解的P-T曲线吻合较好。这可以通过在水饱和条件下可获得自由水来解释。甲烷水合物在非饱和条件下分解的P-T曲线向低温高压区移动。在压力为6 MPa时，孔径为50 nm的样品的分解温度比纯水中低1.2K，孔径为10 nm的样品的分解温度比纯水中低6 K。这一结果是由于孔隙水高度束缚在小毛细管一侧。这些数据与由NMR技术获得的未冻水含量的数据进行了比较。