Advanced NMR-based techniques for pore structure analysis of coal. Final project report Page: 3 of 62
This report is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to UNT Digital Library by the UNT Libraries Government Documents Department.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
Size analysis in the large micropore size range (1-2 nm) is difficult for a variety of
reasons including difficulty in obtaining materials with known size and pore
geometry in this range. We have synthesized and purified a nearly phase-pure form
of the tubular aluminosilicate, imogolite, which has a nominal diameter of 1.2 nm.
By replacing some silicon with germanium, the pore size can be varied in a
systematic manner. We have used this material to explore the suitability of "'Xe
NMR as well as '4N2 and 5N2 NMR as pore size probes in this size range.
As a result of this work, eight refereed publications have either been published, are
in press, or have been submitted. Two graduate students obtained MS degrees in
chemical engineering with full support from the project. One student was hired by
a carbon company, the Cabot Corporation, who is having the student remain at the
University to pursue his PhD in the area of adsorption and the second student is
working for a chemical company in Houston.
I. Background
One of the main problems in coal utilization is the inability to properly characterize
its complex pore structure. Coals typically have micro/ultra-micro 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. We investigate 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. In particular, we study the interaction between several small
molecules (129Xe, 14N2, 15N2) and pore surfaces.
Upcoming Pages
Here’s what’s next.
Search Inside
This report can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Report.
Smith, D. M.; Hua, D. W. & Earl, W. Advanced NMR-based techniques for pore structure analysis of coal. Final project report, report, February 1, 1996; United States. (https://digital.library.unt.edu/ark:/67531/metadc667077/m1/3/: accessed April 25, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.