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Changes in Pore Structure of Coal Associated with Sc-CO2 Extraction during CO2-ECBM.
- Source :
- Applied Sciences (2076-3417); Sep2017, Vol. 7 Issue 9, p931, 11p
- Publication Year :
- 2017
-
Abstract
- Supercritical CO<subscript>2</subscript> (Sc-CO<subscript>2</subscript>), a supercritical solvent, can extract small organic molecules (fluid) from coal, changing pore structures to affect gases storage and migration in the coal matrix. Five undeformed coals before and after the second coalification jump were collected to simulate Sc-CO<subscript>2</subscript> extraction performed with supercritical extraction equipment. Pore structures of the samples before and after Sc-CO<subscript>2</subscript> extraction were characterized using mercury porosimetry. The results show that there are significant changes in pore size distribution of samples. ΔVMa and ΔVMe of coal samples are positive, ΔVTr and ΔVMi are positive for most coals, and ΔVMi of higher coals are negative; the ΔSMa and ΔSMe are positive with small values, the ΔSTr and ΔSMi are positive and negative before and after the second coalification jump; thus, the pore connectivity is improved. These results indicate that Sc-CO<subscript>2</subscript> extraction not only increases the numbers of micropores, but also enlarges the pore diameter size; these changes in the pore structure are influenced by the second coalification. The changes in the pore structure by Sc-CO<subscript>2</subscript> extraction provide more spaces for gas storage and may improve the pore throats for gas migration. [ABSTRACT FROM AUTHOR]
- Subjects :
- SUPERCRITICAL carbon dioxide
COALBED methane
GAS migration
Subjects
Details
- Language :
- English
- ISSN :
- 20763417
- Volume :
- 7
- Issue :
- 9
- Database :
- Complementary Index
- Journal :
- Applied Sciences (2076-3417)
- Publication Type :
- Academic Journal
- Accession number :
- 125352958
- Full Text :
- https://doi.org/10.3390/app7090931