Structure and thermal expansion of natural gas clathrate hydrates

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作者：

S Takeya，M Kida，H Minami，H Sakagami，A Hachikubo，N Takahashi，H Shoji，V Soloviev，K Wallmann，N Biebow

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摘要：

We report on the structural properties of natural gas hydrate crystals from the Sea of Okhotsk. Using powder X-ray diffraction (PXRD), it was determined that sediments from four locations contained type I gas hydrate, which encage mostly methane (96–98%) and a small amount of carbon dioxide. For all hydrates, the lattice constant was estimated to be 11.85 A at 113 K, which approximately equals that of pure methane hydrate. The result is in good agreement with the structure of artificially synthesized methane + carbon dioxide mixed-gas hydrates. These results suggest that the lattice constant of the natural gas hydrate does not change due to a change of CO 2 gas content. In addition, the thermal expansion of the sampled hydrate was measured for the temperature range of 83–173 K, and the resulting density of the hydrate crystal at 273 K was estimated to be 0.92 g / cm 3. These results are essential for applying natural gas hydrates as an alternative natural fuel resources.

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关键词：

Practical, Experimental/ crystal structure lattice constants natural gas technology organic compounds thermal expansion X-ray diffraction/ structural properties thermal expansion natural gas clathrate hydrate crystals Okhotsk Sea powder X-ray diffraction pure methane hydrate lattice constant artificially synthesized methane carbon dioxide mixed-gas hydrates natural fuel resources 83 to 173 K 273 K/ A6165 Crystal structure of specific organic compounds E3020 Mining, oil drilling and natural gas industries/ temperature 8.3E+01 to 1.73E+02 K temperature 2.73E+02 K