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Advanced NMR-based techniques for pore structure analysis of coal. Quarter report {number_sign}8, 7/1/93--9/30/93

Technical Report ·
DOI:https://doi.org/10.2172/10117696· OSTI ID:10117696
One of the main problems in coal utilization is the inability to properly characterize its complex pore structure. Coals typically have micro/ultramicro pores but they also exhibit meso and macroporosity. Conventional pore size techniques (adsorption/condensation, mercury porosimetry) are limited because of this broad pore size range, microporosity, reactive nature of coal, samples must be completely dried, and network/percolation effects. Small angle scattering is limited because it probes both open and closed pores. Although one would not expect any single technique to provide a satisfactory description of a coal`s structure, it is apparent that better techniques are necessary. Small angle scattering could be improved by combining scattering and adsorption measurements. Also, the measurement of NMR parameters of various gas phase and adsorbed phase NMR active probes can provide pore structure information. The dependence of the common NMR parameters such as chemical shifts and relaxation times of several different nuclei and compounds on the pore structure of model microporous solids, carbons, and coals is investigated. In particular, the interaction between several small molecules ({sup 129}Xe, {sup 3}He, {sup 14}N{sub 2},{sup 14}NH{sub 3},{sup 15}N{sub 2},{sup 13} CH{sub 4}, {sup 13}CO{sub 2}) and pore surface is studied.
Research Organization:
New Mexico Univ., Albuquerque, NM (United States). Center for Micro-Engineered Ceramics
Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
FG22-91PC91296
OSTI ID:
10117696
Report Number(s):
DOE/PC/91296--8; ON: DE94005760
Country of Publication:
United States
Language:
English