CPMAS 13C NMR and pyrolysis-GC-MS studies of structure and liquefaction reactions of Montana subbituminous coal

Chen, Song; Hou, Lei; Saini, Ajay; Hatcher, Patrick G.; Schobert, Harold H.

doi:10.1016/0378-3820(93)90069-g

Cited by 45 publications

(17 citation statements)

References 26 publications

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“…A small spin sideband with low intensity, which indicates an aromatic ring, was observed in the region of 200–240 ppm . The aliphatic carbon has methyl groups at 0–25 ppm, methylene carbon appears within the region of 25–50 ppm, and methoxyl groups resonates at 50–65 ppm, while the ester group appears at 65–80 ppm. , PAA extracts of the float fractions and their residues gave similar spectra in the aromatic and aliphatic regions. When comparing the peak intensities of the float fractions, residues, and the PAAs, peak broadening was observed for the float fractions and the residues in the aromatic and aliphatic regions.…”

Section: Resultsmentioning

confidence: 81%

Influence of Density Separation of Selected South African Coal Fines on the Products Obtained during Liquefaction Using Tetralin as a Solvent

et al. 2019

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The liquefaction of two South African discarded coal fines and their density separated (float) fractions were carried out under moderate conditions in a laboratory autoclave. Liquefaction tests were carried out on both discarded coal fines and their float fraction samples at temperatures ranging between 380 and 420 °C using tetralin as a solvent and an initial nitrogen gas pressure of 3 MPa. Oil samples produced from the liquefaction of coal fines discards and their float fractions were further characterized using gas chromatography–mass spectrometry (GC–MS) and nuclear magnetic resonance. The liquefaction test results showed that carbon conversions and oil yields were higher for the float fractions when compared to the discarded coal fines samples. The oil yields ranged from 24.4–37.2% (dry ash free (daf)) for the oil produced from the float fractions of the coal fines and 19.1–29.3% for oils produced from the coal fines (daf). The oil and the gas yields of the float fraction samples were higher when compared to those of the coal fines discards. The higher carbon conversion and higher oil yields obtained from the float fractions demonstrated that density separation of the coal fines discards improves the overall carbon conversion and liquefaction yields. Coal fines discards and float fractions achieved 8 wt % (daf) and 10 wt % (daf) PAA yields at 420 °C, respectively, using tetralin as a solvent during liquefaction. The Waterberg and Highveld coal float fractions had carbon conversions of 50.7 wt % (daf) and 52.7 wt % (daf), respectively, in comparison to <42 wt % (daf) carbon conversion of the original discarded coal fines. GC–MS results for the oil samples derived from coal fines discards and their float fractions showed that these oils contained 72 and 81 wt % naphthalene, respectively. Density separation of discarded coal fines is beneficial to produce a float fraction that may be used as feedstock for direct coal liquefaction. The analytical results indicate that density separation of the coal fines may be used to reduce high costs and volumes of discarded coal fines associated with the disposal and handling of discarded coal fines. Environmental problems will also be addressed if discarded coal fines are utilized as feedstock for industrial processes.

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Section: Resultsmentioning

confidence: 81%

Influence of Density Separation of Selected South African Coal Fines on the Products Obtained during Liquefaction Using Tetralin as a Solvent

et al. 2019

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“…6. It is reasonable to assume that the pretreatment of coal with [Bmim]Cl can break bridge bonds, such as OH-self-associated hydrogen bonds, aliphatic bridges and -C-O-, consequently, resulting in structural relaxation of the pretreated coal and escape of lower molecular weight species such as aliphatic, and oxygen-bound carbons from the network [42]. To verify the proposed mechanism, further experiments are necessary and still in progress.…”

Section: Mechanism Of Il Pretreatment Of Coalmentioning

confidence: 97%

Pretreatment of coal by ionic liquids towards coal electrolysis liquefaction

Liu

Zhou

Tang

et al. 2015

Fuel

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“…A derivation of the carbon-13 magnetic resonance technique, crosspolarization (CP) "C NMR, offers several advantages over the conventional technique (Miknis et al, 1981;Smith and Smoot, 1990;Song et al, 1993). The results from this method have been used to indicate that the higher rank coals are indeed highly aromatic substances, and the cross-polarization I3C NMR could be used with confidence to determine the carbon aromaticity.…”

Section: B Magnetic Resonance Spectroscopymentioning

confidence: 97%

Application of Spectroscopic Techniques to the Structural Analysis of Coal

Speight

1994

Applied Spectroscopy Reviews

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CPMAS 13C NMR and pyrolysis-GC-MS studies of structure and liquefaction reactions of Montana subbituminous coal

Cited by 45 publications

References 26 publications

Influence of Density Separation of Selected South African Coal Fines on the Products Obtained during Liquefaction Using Tetralin as a Solvent

Influence of Density Separation of Selected South African Coal Fines on the Products Obtained during Liquefaction Using Tetralin as a Solvent

Pretreatment of coal by ionic liquids towards coal electrolysis liquefaction

Application of Spectroscopic Techniques to the Structural Analysis of Coal

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