Effects of ethanol-mixed supercritical CO2fluid on CO2adsorption on coals: implications for CO2geologic storage in coal seams
- Resource Type
- Article
- Authors
- Zhang, Dengfeng; Hu, Zichao
- Source
- International Journal of Global Warming; 2020, Vol. 21 Issue: 3 p274-286, 13p
- Subject
- Language
- ISSN
- 17582083; 17582091
The coal matrix swelling induced by CO2decreases the permeability of the target coal seams, and it will trigger disadvantages to CO2storage in deep coal reservoirs. In order to mitigate such swelling effect, the addition of ethanol into CO2is proposed. The effects of ethanol-mixed supercritical CO2on the adsorption equilibrium and kinetics behaviors of CO2adsorption on coals are studied in this paper. The results indicate that the ethanol-mixed supercritical CO2fluid could increase CO2adsorption capacity of two coals with low metamorphic degree, but decrease that of two coals with high metamorphic degree. The addition of ethanol into CO2fluid remarkably enhances the diffusion and adsorption rate of CO2within the micropores and macropores of coals. The alterations of pore system of various rank coals could account for the changing law of CO2adsorption equilibrium and kinetics behaviors on coals after interacting with ethanol-mixed supercritical CO2.