Changes in the pore structure of coal with chemical processing. [31 refs]
Carbon dioxide adsorption experiments gave the same BET surface areas at room temperature and at dry ice temperature for a molecular sieve, an alumina catalyst, and a Wyoming subbituminous coal. This suggested that activated diffusion was not an important factor, even at 196/sup 0/K. However, the adsorption of CO/sub 2/ on Illinois No. 6 coal decreased with increasing temperature. Surface area variations of desulfurized coal, extracted coal, and reacted coal were examined by carbon dioxide adsorption at 196/sup 0/K. The use of NaOH to remove S from Illinois No. 6 coal appeared to cause partial blockage or collapsing of the pore structure. Subsequent extraction removed these obstructions somewhat. This conclusion was suggested by a minimum in the curve of surface area versus extraction time. Pyridine extractions of Roland Seam coal appeared to open new areas that were previously inaccessible to carbon dioxide. The surface areas were nearly doubled, but the average pore diameter appeared to remain essentially unchanged as evidenced by neopentane adsorptions. Large solvent molecules such as benzene were able to penetrate the coal pores, whereas a large, symmetrical molecule such as neopentane could not. These results suggest that the pores are slot shaped rather than cylindrical.
- Research Organization:
- California Univ., Berkeley (USA). Lawrence Berkeley Lab.
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 7233437
- Report Number(s):
- LBL-5272
- Country of Publication:
- United States
- Language:
- English
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010600* -- Coal
Lignite
& Peat-- Properties & Composition
ADSORBENTS
ALKALI METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CARBONACEOUS MATERIALS
CATALYSTS
CHALCOGENIDES
CHEMICAL COMPOSITION
CHEMICAL REACTIONS
COAL
DESULFURIZATION
ELEMENTS
ENERGY SOURCES
EXTRACTION
FOSSIL FUELS
FUELS
HYDROGEN COMPOUNDS
HYDROXIDES
MOLECULAR SIEVES
NONMETALS
OXIDES
OXYGEN COMPOUNDS
POROSITY
REMOVAL
SEPARATION PROCESSES
SODIUM COMPOUNDS
SODIUM HYDROXIDES
SOLVENT EXTRACTION
SOLVENT-REFINED COAL
SORPTION
SUBBITUMINOUS COAL
SULFUR
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE