Changes in the pore structure of coal with progressive extraction
Adsorption of four gases (CO/sub 2/, CF/sub 4/, N/sub 2/, and Ar) on Wyodak mine, Roland seam coal, Illinois No. 6 high-sulfur coal, and 4A and 5A Linde molecular sieves has been studied. The results strongly suggest that coals possess a molecular sieve structure. The Roland seam coal is found to resemble the 4A sieve in its microporous structure (in which a majority of the pores are 4 angstroms in diameter), whereas the Illinois No. 6 coal closely resembles the 5A seive (with a majority of the pores just under 5 angstroms). To interpret these measurements the molecular cross-sectional areas of argon at 77/sup 0/K and of carbon dioxide and carbon tetrafluoride at 196/sup 0/K were determined by comparison to nitrogen adsorptions at 77/sup 0/K on two Harshaw catalysts. Values of 17.0, 23.4, 17.3 angstroms/sup 2/ were obtained for the argon, carbon dioxide, and carbon tetrafluoride molecules, respectively. Comparisons between surface areas determined by both the Brunauer-Emmett-Teller and Dubinin-Polanyi equations for the low-temperature adsorptions of N/sub 2/, Ar, and CO/sub 2/ on the catalysts, molecular sieves, and raw coals indicate that either equation gives similar surface areas. (auth)
- Research Organization:
- California Univ., Berkeley (USA). Lawrence Berkeley Lab.
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 7365889
- Report Number(s):
- LBL-4439
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
010600* -- Coal
Lignite
& Peat-- Properties & Composition
ADSORPTION
ARGON
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CARBONACEOUS MATERIALS
CATALYSTS
CHALCOGENIDES
COAL
CRYOGENIC FLUIDS
ELEMENTS
ENERGY SOURCES
FLUIDS
FLUORINATED ALIPHATIC HYDROCARBONS
FOSSIL FUELS
FUELS
HALOGENATED ALIPHATIC HYDROCARBONS
NITROGEN
NONMETALS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POROSITY
RARE GASES
SORPTION
SORPTIVE PROPERTIES
SURFACE PROPERTIES