Measurement of Clathrate-Hydrate Film Thickness Formed At The Interface Between Liquid CO_2 and Water

摘要

Liquid CO_2 dissolution observed at CO_2 sequestration in the ocean, CO_2 mitigation strategy, is accompanied by CO_2 clathrate-hydrate film, which has a large effect on the estimation of the strategy. Therefore, the mechanism of CO_2 dissolution with hydrate film is a point of special interest. From this viewpoint, the present paper presents a new technique to measuring the thickness of the hydrate film formed at the interface between liquid CO_2 and water. The technique is based on the dissolution model of liquid CO_2 with hydrate film whose unique thickness is maintained by the dissolution at the water side and formation at the liquid CO_2 side in the process of CO_2 dissolution. If the hydrate is not formed at the liquid CO_2 side, only the dissolution occurs and its characteristics is applied to the measurement of the thickness of hydrate film. Using a high pressure experiment apparatus, a water deoplet was injected into the liquid CO_2 to attach the hydrate film. The water droplet has an effect to stop the hydrate formation. After 2.1 s, the hydrate film disappeared at the contact point. The hydrate thickness was estimated to be about 0.43 #mu# m using these data. It was confirmed that the experimental results also have supported the dissolution model.