HR: 1340h
AN: V13D-1586    [Abstracts]
TI: The Oil Potential Of Coal Macerals Evaluated By Spectroscopy Techniques
AU: * Mo, H
EM: b87204036@ntu.edu.tw
AF: Department of Geosciences, National Taiwan University, No.1, Sec. 4, Roosevelt Rd., Da- an District, Taipei City, Taipei, 106, Taiwan
AU: Huang, W
EM: wlhuang@ntu.edu.tw
AF: Department of Geosciences, National Taiwan University, No.1, Sec. 4, Roosevelt Rd., Da- an District, Taipei City, Taipei, 106, Taiwan
AB: The constituents of coal have been categorized into three major maceral groups namely exinite (liptinite), vitrinite, and fusinite. Each maceral group, which was thought to possess different oil generation potential, has been visually confirmed by DAC-pyrolysis. This study analyzed eighteen maceral samples separated from Polish Carboniferous coals using nondestructive spectroscopy techniques include FTIR, solid-state ¹³C nuclear magnetic resonance (¹³C NMR), and XRD to obtain the information about the molecular structure in order to correlate these characteristics with the oil generative potential estimated from our visual observations. The correlation between the infrared spectroscopy with our visual observations suggests that exinite group which generated large amounts of oil has the lowest aromatics/aliphatics ratio, whereas the inert fusinite group has the highest. The proportion of aromatic carbon increases with increasing maturity within the same maceral group. The NMR spectra, similar to FTIR spectra, showed distinct representative bands for aliphatic and aromatic functional groups in the macerals. The analyses of the representative samples confirm the previous thought that exinite contains lower aromaticity value (fa) than vitrinite and fusinite. For vitrinite group which composed of different composition and structure, the aromatics/aliphatics ratios appear lower in oil-generated samples and higher in non oil-generated ones. Besides, an excellent correlation between these two analytical methods suggests that FTIR and NMR are valuable independent methods for quantitative study of organic matters. The quantitative x-ray diffraction analysis was not carried out because of the weak reflections due to small amounts of studied maceral samples. The XRD, however, showed qualitatively a considerable variation of diffraction patterns for four exinite samples but little variation for vitrinite and fusinite samples. The patterns for four exinite samples are significant different from vitrinite and fusinite. This observation is qualitatively consistent with those observed from the NMR, IR and visual studies, showing low aromatics/aliphatics ratio, thus high oil yields in exinite. In conclusion, the visual observations of oil generative potential are generally consistent with those implied from FTIR, NMR, and XRD. All of these spectroscopy analyses confirm that the oil potential of coals is related to their chemical structure, predominantly aromatic and aliphatic functional groups.
DE: 1051 Sedimentary geochemistry
DE: 1055 Organic and biogenic geochemistry
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting