Dissociation Heat of Natural Gas Hydrate
Natural gas hydrates stored in permafrost, marine and lake sediments play an important role as a great reserve of carbon in the world. Gas hydrates release or absorb large latent heat in their phase changes and affect thermal condition themselves. Thermal properties of gas hydrates are important to understand the formation, dissociation and maintenance processes of gas hydrates in natural conditions. In this study dissociation heat of natural gas hydrates were measured using heat-flow calorimeter (Setaram BT2.15) under high-pressure and low-temperature conditions. About lg of gas hydrate samples obtained from Sea of Okhotsk and Lake Baikal were ground up in liquid nitrogen and put into a small pressure cell. The cell was put into the calorimeter at 90K and then heated from 90K to 303K at the rate of 0.15K per minute. Dissociation heat of gas hydrate was obtained by integration of the peak of heat flow between 130K and 220K. Those values from Sea of Okhotsk and Lake Baikal were obtained as 20 ± 2 (kJ mol<-1>) and 24 ± 6 (kJ mol<-1>), respectively. Their minimum values agree well with the literature value of 18.13 ± 0.27 (kJ mol<- 1>) for pure methane hydrate by Handa (1986). Samples of Sea of Okhotsk contained several percent of hydrogen sulfide and small amount of ethane, and some samples obtained from Lake Baikal contains much ethane. In their thermograph several peaks appeared and the relation between temperature and pressure in the cell seemed to be shifted from those for pure methane hydrate because of mixed-gas hydrates.
gas hydrate calorimeter gas composition Sea of Okhotsk Lake Baikal
Akihiro Hachikubo Hirotoshi Sakagami Nobuo Takahashi Hitoshi Shoji Oleg Khlystov Tamara Zemskaya Anatoly Obzhirov Leonid Mazurenko
Kitami Institute of Technology, Japan Limnological Institute, SB RAS, Russia Pacific Oceanological Institute, FEB RAS, Russia All-Russia Research Institute for Geology and Mineral Resources of the World Ocean, Russia
国际会议
2006现代科技国际研讨会(The International Workshop on Modern Science and Technology in 2006)
北京
英文
113-115
2006-04-01（万方平台首次上网日期，不代表论文的发表时间）