Journal of Northeastern University(Natural Science) ›› 2023, Vol. 44 ›› Issue (5): 726-734.DOI: 10.12068/j.issn.1005-3026.2023.05.016

• Resources & Civil Engineering • Previous Articles     Next Articles

Study on Coal Deformation and Adsorption Stress Caused by Supercritical CO2 Adsorption

WANG Lei, YANG Dong, XING Jun-wang   

  1. Key Laboratory of In-situ Property Improving Mining of Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China.
  • Published:2023-05-24
  • Contact: WANG Lei
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Abstract: The constant temperature adsorption of helium/supercritical CO2(SC-CO2) and deformation of coal are tested, the axial deformation and radial deformation of coal are real-time monitored, and the coal expansion deformation caused by effective stress and adsorption stress and the adsorption stress of coal to SC-CO2 are revealed. The results show that the axial strain by coal adsorption of different gases is higher than the radial strain, and the variation law of coal strain caused by helium and SC-CO2 with gas injection pressure is similar. In the process of increasing the temperature, the volume strain of coal adsorbed helium increased first and then decreased, while the volume strain of coal adsorbed SC-CO2 gradually decreased. With the increase of temperature, the deformation of coal during the adsorption of SC-CO2 gradually changed from the deformation caused by adsorption stress to the deformation caused by effective stress. The ratio of the volume strain of adsorption stress to the volume strain of effective stress is gradually decreased. The adsorption stress of coal to SC-CO2 decreases with the increase of temperature. When the temperature increases from 60℃ to 80℃, the adsorption stress only decreases by 29%. At the same time, the ratio of SC-CO2 adsorption stress to gas adsorption stress reaches the maximum at 60 ℃, and the SC-CO2 has the best gas displacement effect at this temperature.

Key words: adsorption deformation; adsorption stress; effective stress; supercritical CO2(SC-CO2); thermal mechanical coupling

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