高圧水との界面にハイドレート膜を伴う液体CO_2の溶解機構とその熱力学的考察

概要

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Dissolution of liquid CO_2 accompanied by CO_2 clathrate-hydrate film into sea water is observed at CO_2 sequestration in ocean, which is considered to be an effective strategy of CO_2 mitigation. The dissolution mechanism was experimentally investigated by considering the relation between measured CO_2 surface concentration of hydrate-covered CO_2 droplets and CO_2 solubility. It was made clear that, in the temperature range of hydrate formation, the measured surface concentration decreases with the decrease of temperature and it exactly corresponds to CO_2 solubility. This fact indicates that the dissolution rate of a CO_2 droplet with hydrate film is controlled by the mass transfer rate of dissolved CO_2 at the droplet surface into water and the decrease of dissolution rate is caused by the decrease of CO_2 solubility in the hydrate formation region. Further, in order to clarify the decreasing mechanism of CO_2 solubility, a thermodynamic method was employed. CO_2 solubility was estimated from the relationship between the molar Gibbs free energy of water-liquid CO_2 mixture and that of hydrate and it has shown that the present method could predict the decrease of CO_2 solubility in hydrate formation region fairly well.
一般社団法人日本機械学会の論文
1998-07-25