Kinetic evaluation of progress in coal liquefaction in the 1t/d PSU for the NEDOL process

Ito, Koichi; Sakawaki, Kouji; Nogami, Yasuyuki; Inokuchi, Kenji; Imada, Kunihiro

doi:10.1016/s0016-2361(99)00172-6

Cited by 29 publications

(17 citation statements)

References 3 publications

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“…The liquefaction residues from Tanito Harum and Wyoming coals were obtained in the 1 t/d Process Supporting Unit (PSU) constructed for the support studies on the operations of the PP. 51 The operating conditions and the process flow of the PSU are almost similar with those of the PP. The solid residues from distillation of the coal extracts were pulverized to pass through a 60-mesh screen and dried for 2 h under vacuum at 110 °C before use.…”

Section: Methodsmentioning

confidence: 82%

Molecular Size Determination of Coal-Derived Asphaltene by Fluorescence Correlation Spectroscopy

et al. 2011

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The molecular properties of asphaltenes have been the subject of uncertainty in the literature; in particular the molecular architecture is still a matter of debate. Some literature reports provide evidence that the contrast of petroleum asphaltenes versus coal-derived asphaltenes is useful for understanding the governing principles of asphaltene identity. Here, we employ fluorescence correlation spectroscopy to measure the diffusion constants of asphaltenes obtained from the distillation resid from coal liquefaction fluids. Concentrations employed herein are ∼10−8 molar, precluding asphaltene aggregation. These are compared with the same measurements on petroleum asphaltenes. These results confirm that the molecular sizes of these coal-derived asphaltenes are much smaller than virgin petroleum asphaltenes. Coal-derived asphaltenes are simpler than petroleum asphaltenes and provide correspondingly tighter constraints for understanding asphaltene molecular architecture. The small size, small alkane fraction, and large PAH of coal-derived asphaltenes are consistent with an “island” molecular architecture.

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Section: Methodsmentioning

confidence: 82%

Molecular Size Determination of Coal-Derived Asphaltene by Fluorescence Correlation Spectroscopy

et al. 2011

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“…The Wyoming coal CDA was obtained by a similar liquefaction and distillation process; this is also a residual asphaltene. 54 Immature source rock asphaltene (ISA) was extracted from an unweathered outcrop from an immature section of the Eagle Ford. 55 The bitumen fraction of that rock was isolated by Soxhlet extraction in 90:10 dichloromethane:methanol.…”

Section: ■ Experimental Methodsmentioning

confidence: 99%

“…The asphaltene fraction, which is toluene soluble and n -hexane-insoluble, was obtained by Soxhlet extraction of the distillation residue. The Wyoming coal CDA was obtained by a similar liquefaction and distillation process; this is also a residual asphaltene …”

Section: Experimental Methodsmentioning

confidence: 99%

Nanoaggregates of Diverse Asphaltenes by Mass Spectrometry and Molecular Dynamics

Wang

Taylor

et al. 2017

Energy Fuels

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Asphaltene nanoaggregates from three diverse source materialscoal-derived asphaltenes dominated by aromatic carbon, petroleum asphaltenes with comparable abundances of aromatic and aliphatic carbon, and immature source-rock asphaltenes dominated by aliphatic carbonare examined by means of surface-assisted laser desorption ionization mass spectrometry (SALDI-MS) coupled with laser desorption laser ionization mass spectrometry (L2MS). All three types of asphaltenes form nanoaggregates with aggregation numbers close to 7. Molecular dynamics calculations for proposed island molecular structures show the important roles that π-stacking and alkane steric hindrance play in nanoaggregate formation and structure. These results are discussed in terms of entropy and enthalpy changes. All results are consistent with the Yen-Mullins model, which bodes well for its expanded use in oilfield reservoir evaluations.

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“…Sakawaki et al reported that a higher G/L tends to prolong residence time of the heavy distillate in the liquefaction reactors. In previous experiments with the 1 t/d PSU, higher reaction temperatures of up to 738 K resulted in lower residue yield and higher oil yield . However, in the experiments with Shenhua coal shown in Figure , a longer residence time seems to be effective to improve the oil yield through conversion of asphaltene to heavy oil and conversion of heavy oil to light oil.…”

Section: Resultsmentioning

confidence: 88%

Possibility of Increased Oil Yield in the NEDOL Process

Wasaka¹,

Ibaragi²,

Itonaga³

et al. 2002

Energy Fuels

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A maximum oil yield in the NEDOL coal liquefaction process was obtained with coal containing 76-78% carbon, while gas and water yields decreased with an increase in the carbon content. On the other hand, residue yield increased with an increase in the carbon content and this was attributed to an increase in asphaltene [(hexane insoluble)-(toluene soluble)] in the residue. From the experimental results, it was inferred that decomposition of the asphaltene is inevitable for improvement of the oil yield and that prolonged residence time in the liquefaction reactors is the most effective and practical measure for decomposing the asphaltene under the operating conditions of the NEDOL process. The average structure of the hexane soluble, asphaltene and preasphaltene [(toluene insoluble)-(THF soluble)] in the liquefaction residue exhibited the similar structural parameters in coals tested in the NEDOL coal liquefaction plants. The asphaltene fraction was then extracted from the residue by commercially applicable extraction conditions following which the extract was hydrotreated. About 35% of the extract was recovered as oil, which is lighter than 811K boiling point, by hydrotreatment. Furthermore, coal liquefaction experiments that used the extract as a part of solvent were conducted and an increase in total liquefaction oil yield was confirmed comparing with a coal liquefaction experiment without the extract.

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Kinetic evaluation of progress in coal liquefaction in the 1t/d PSU for the NEDOL process

Cited by 29 publications

References 3 publications

Molecular Size Determination of Coal-Derived Asphaltene by Fluorescence Correlation Spectroscopy

Molecular Size Determination of Coal-Derived Asphaltene by Fluorescence Correlation Spectroscopy

Nanoaggregates of Diverse Asphaltenes by Mass Spectrometry and Molecular Dynamics

Possibility of Increased Oil Yield in the NEDOL Process

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