Simulation experiment of carbon dioxide storage in coal seam.

In order to study the capacity of CO2 storage in coal bed and the displacement of methane CH4 in coal by CO2 injection, an experiment about the CO2 adsorption and coalbed methane ( CBM) replacement in coal under given pressure was carried out with coal specimens of large size (100 mm x100 mm x 200 mm) from the No. 3 coal seam, Qinshui Basin, China. Based on the experiment, the CO2 storage capacity difference between coal containing CH4 and coal without CH4 was contrastively analyzed. The experimental results demonstrate that, the storage of CO2 in the coal specimen can amount to 11. 03 L under the in-situ stress condition of the coal bed and injection pressure of 0. 5 MPa. CO2 permeability through the coal decreases with the increase of its adsorption amount during the experiment duration of 180 min. When the CO2 injection pressure increases to 1. 0 MPa from 0. 5 MPa under the same confining stresses, the CO2 storage amount in the coal increases by 93. 00%, the storage rate increases by 13. 50% and the amount of CH4 desorption increases by 18. 13%. It is found that the amount of CH4 desorption is larger than CO2 adsorption in the initial experimental stage. After that, the amount of CH4 desorption tends to be stable but far less than CO2 adsorption amount. Under the similar experimental condition, the CO2 storage capacity in coal containing CH4 is 59. 29% more than that of coal without CH4 and the storage rate in coal containing CH, increases by 12. 51% compared that in coal without CH4. [ABSTRACT FROM AUTHOR]