Diffusion of gases in coals and chars. Technical progress report No. 3, March 15-June 14, 1986
Surfaces areas of 13 PSOC coals have been measured by nitrogen adsorption at 77 K and carbon dioxide adsorption at 273 K. Surfaces areas were extracted from nitrogen adsorption isotherms using the BET theory. Mercury intrusion experiments have been conducted for all eight Group A PSOC coals. Traditional analysis of this pressure-volume data would indicate that there is substantial pore volume with average pore radius greater than approx.0.1 ..mu..m. However, this low pressure intrusion is more likely the result of mercury filling the regions were coal particles are touching. This view is supported by the observed differences between intrusion in the large and fine particles. The application of NMR spin-lattice relaxation measurements of water in porous solids is investigated as a possible tool for the determination of pore size distributions. NMR methods have several potential advantages over conventional porosimetry/adsorption techniques including the study of wet porous solids, a wide range of sample sizes may be studied, and the fact that no pore shape assumption is required. In principle, water contained in a pore will relax faster than bulk water. This decrease in the observed relaxation rate decay constant, T/sub 1/, is directly related to the pore volume to surface area ratio (i.e., hydraulic radius) according to the two-fraction, fast exchange model. However, the suitability of this model and NMR spin-lattice relaxation measurements for the determination of pore size distribution has not been previously demonstrated. 23 refs., 11 figs., 4 tabs.
- Research Organization:
- New Mexico Univ., Albuquerque (USA). Powders and Granular Materials Lab.
- DOE Contract Number:
- FG22-85PC80519
- OSTI ID:
- 5788846
- Report Number(s):
- DOE/PC/80519-3; ON: DE86012785
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
010600* -- Coal
Lignite
& Peat-- Properties & Composition
ADSORPTION
ADSORPTION ISOTHERMS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CARBONACEOUS MATERIALS
CHALCOGENIDES
COAL
CRYSTAL STRUCTURE
ELEMENTS
ENERGY SOURCES
FOSSIL FUELS
FUELS
ISOTHERMS
MAGNETIC RESONANCE
MATERIALS
MEASURING INSTRUMENTS
MICROSTRUCTURE
NITROGEN
NONMETALS
NUCLEAR MAGNETIC RESONANCE
OXIDES
OXYGEN COMPOUNDS
POROSIMETERS
POROSITY
RESONANCE
SORPTION
SURFACE AREA
SURFACE PROPERTIES