Formation and storage characteristics of CO2 hydrate in porous media: Effect of liquefaction amount on the formation rate, accumulation amount

Abstract

• Formation and storage characteristics of CO 2 hydrate was revealed under different liquefaction conditions. • The influence of liquefaction amount on hydrate formation was illustrated in porous media. • The formation rate of CO 2 hydrate reached to 6.32 × 10 −4 mol/h under partial liquefaction conditions. • The increment of CO 2 formation rate was 3.22 × 10 −4 mol/h in porous media compared with the non-liquefaction condition. • An optimal liquefaction amount occurred in promoting the formation process of CO 2 hydrate in porous media. Hydrate-based CO 2 capture and storage is considered to be an effective way to reduce greenhouse gas emissions and mitigate global warming. Evaluation of the formation and storage characteristics require to illuminate the dependence of CO 2 phase behavior and the formation properties of hydrate in porous media. In this work, the formation process of CO 2 hydrate was investigated to elucidate the influence mechanism and law of different liquefaction amount on the formation characteristics of CO 2 hydrate in porous media. The results showed that CO 2 liquefaction significantly promoted the formation process of hydrate and the liquefied amount was a critical factor in affecting the formation process of CO 2 hydrate in porous media. Compared with the condition of non-liquefaction, the higher formation rate and larger gas storage capacity were obtained under liquefaction conditions. The formation rate of CO 2 hydrate reached 6.32 × 10 −4 mol/h under the condition of partial liquefaction. Furthermore, the formation rate of CO 2 hydrate increased with the initial pressure increasing in the experiments. However, there was an optimal liquefaction amount occurred in promoting the hydrate formation in porous media. The formation rate of CO 2 hydrate sharply decreased and it was only 3.4 × 10 −4 mol/h under condition of complete liquefaction. The results further indicated that, CO 2 liquefaction could promote the formation process of CO 2 hydrate in porous media within a certain range of liquefaction amount. These results will provide a theoretical guidance and reference for sequestration and storage of CO 2 gas in the form of hydrate in sediments.