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Title: /sup 13/C NMR structural determination of the coals in the premium coal sample bank

Conference · · Prepr. Pap., Am. Chem. Soc., Div. Fuel Chem.; (United States)
OSTI ID:5974411

Solid state /sup 13/C cross polarization (CP) magic angle spinning (MAS) NMR experiments have become very useful for the study of the structure of coal and other fossil fuels. Solid state NMR techniques have the advantage over liquid NMR methods because the whole solid coal can be analyzed in a nondestructive manner and no assumption need be made that the soluble portion represents the whole organic portion of the coal. From CP/MAS experiments twelve NMR structural parameters may be determined including the aromaticity, f/sub a/, that give information on the carbon skeletal backbone. The variation of the NMR structural parameters for coals of different rank from lignite to anthracite has been demonstrated. The coals in the premium Coal Sample Bank (PCSB) have been included in the set of coals studied at the Advance Combustion Engineering Research Center. The NMR data obtained on these coals will be used to provide chemical structural parameters for refinement of the devolatization sub-model of the PCGC-2 combustion model. This paper reports the twelve structural parameters for two of the PCSB coals, Pittsburgh 8 (HVB) and Blind Canyon (HVB). These data were derived from integrated intensities in a normal CP/MAS experiment along with a complete set of dipolar dephasing experiments. In addition, the proton spin lattice relaxation times for these coals have been determined. From relaxation experiments on the Pittsburgh 8 coal there is some evidence of heterogeneity between different sample vials of the same standard coal.

Research Organization:
Univ. of Utah, Salt Lake City (USA)
OSTI ID:
5974411
Report Number(s):
CONF-870802-
Journal Information:
Prepr. Pap., Am. Chem. Soc., Div. Fuel Chem.; (United States), Vol. 32:4; Conference: 194. American Chemical Society national meeting, New Orleans, LA, USA, 30 Aug - 4 Sep 1987
Country of Publication:
United States
Language:
English