Study on the Effect of Clay Minerals on CO2 Hydrate Formation

Abstract

With the massive emission of greenhouse gases, global warming has become an important challenge for human beings at present. Storing carbon dioxide in the form of solid hydrates in the ocean is an effective strategy to mitigate climate warming. Clay in the ocean may have an effect on hydrate formation and CO₂ storage. In this study, montmorillonite and kaolinite were selected as clay minerals, and the effects of clay particles on CO₂ hydrate formation in suspensions with different mass fractions were experimentally analyzed. The results showed that the clay particles were able to promote hydrate nucleation and shorten the induction time, but the final amount of hydrate was reduced, which was related to the bound water. CO₂ hydrate storage in clay minerals with different water contents was investigated. The amount of CO₂ storage in montmorillonite minerals first decreased and then increased with the increase of water content, while the amount of storage in kaolinite minerals increased. The reason was that the amount of bound water on the surfaces of montmorillonite and kaolinite was different, and the stronger bound water was difficult to form hydrates. The results revealed the effect of clay particles on CO₂ hydrate formation and provided some experimental support for the CO₂ storage by hydrate method in the ocean.