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S Wirick - One of the best experts on this subject based on the ideXlab platform.
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the application of soft x ray microscopy to the in situ analysis of sporopollenin Sporinite in a rank variable suite of organic rich sediments
Other Information: PBD: [1997], 1997Co-Authors: George D Cody, Robert E Botto, S WirickAbstract:Soft X-ray imaging and carbon near edge absorption fine structure spectroscopy (C-NEXAFS) has been used for the in-situ analysis of Sporinite in a rank variable suite of organic rich sediments extending from recent up to high volatile A bituminous coal. The acquisition of chemically based images (contrast based on the 1s - 1{pi}* transition of unsaturated carbon), revealed a homogeneous chemical structure in the spore exine. C-NEXAFS microanalysis indicates chemical structural evolution in sporopollenin/Sporinite with increases in maturation. The most significant change in the C-NEXAFS spectrum is an increase in unsaturated carbon, presumably aromatic, with rank. The rate of aromatization in Sporinite exceeds that of the surrounding vitrinite. Increases in the concentration of unsaturated carbon are compensated by losses of aliphatic and hydroxylated aliphatic carbon components. Carboxyl groups are present in low and variable concentrations. Absorption due to carboxyl persists in the most mature specimen in this series, a high volatile A rank coal. The reactions which drive sporopollenin chemical structural evolution during diagenesis presumably involve dehydration, Diels-Alder cyclo-addition, and dehydrogenation reactions which ultimately lead to a progressively aromatized bio/geopolymer.
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The application of soft X-ray microscopy to the in-situ analysis of sporopollenin/Sporinite in a rank variable suite of organic rich sediments
1997Co-Authors: George D Cody, Robert E Botto, S WirickAbstract:Soft X-ray imaging and carbon near edge absorption fine structure spectroscopy (C-NEXAFS) has been used for the in-situ analysis of Sporinite in a rank variable suite of organic rich sediments extending from recent up to high volatile A bituminous coal. The acquisition of chemically based images (contrast based on the 1s - 1{pi}* transition of unsaturated carbon), revealed a homogeneous chemical structure in the spore exine. C-NEXAFS microanalysis indicates chemical structural evolution in sporopollenin/Sporinite with increases in maturation. The most significant change in the C-NEXAFS spectrum is an increase in unsaturated carbon, presumably aromatic, with rank. The rate of aromatization in Sporinite exceeds that of the surrounding vitrinite. Increases in the concentration of unsaturated carbon are compensated by losses of aliphatic and hydroxylated aliphatic carbon components. Carboxyl groups are present in low and variable concentrations. Absorption due to carboxyl persists in the most mature specimen in this series, a high volatile A rank coal. The reactions which drive sporopollenin chemical structural evolution during diagenesis presumably involve dehydration, Diels-Alder cyclo-addition, and dehydrogenation reactions which ultimately lead to a progressively aromatized bio/geopolymer.
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the application of soft x ray microscopy to the in situ analysis of Sporinite in coal
International Journal of Coal Geology, 1996Co-Authors: George D Cody, Robert E Botto, S WirickAbstract:Abstract Soft X-ray imaging and carbon near edge absorption fine structure spectroscopy (C-NEXAFS) has been used for the in-situ analysis of Sporinite in a rank-variable suite of organic-rich sediments extending from up to high volatile A bituminous coal. The acquisition of chemically based images (con trast based on the 1s−1π∗ transition of unsaturated carbon), reveals a homogeneous chemical structure in the spore exine. C-NEXAFS microanalysis indicates a chemical structural evolution of the sporopollenin bio/geopolymer with increasing maturation. The most significant change in the C-NEXAFS spectrum is an increase in unsaturated carbon, presumably aromatic, with rank. The rate of “aromatization” in Sporinite in coal exceeds that of the associated vitrinite. Increases in the concentration of unsaturated carbon are paralleled by losses of aliphatic and hydroxylated aliphatic carbon components. Carboxyl groups are present in low and variable concentrations. Absorption due to carboxyl persists in the most mature specimen in this series, a high volatile A bituminous coal. The reactions that drive sporopollenin chemical structural evolution during diagenesis presumably involve sequential dehydration, Diels-Alder cyclo-addition, and dehydrogenation reactions that ultimately lead to a progressively aromatized bio/geopolymer.
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C-NEXAFS Microanalysis and Scanning X-ray Microscopy of Microheterogeneities in a High-Volatile A Bituminous Coal
Energy & Fuels, 1995Co-Authors: George D Cody, Robert E Botto, S. K. Behal, Mark M. Disko, S WirickAbstract:Carbon near-edge X-ray absorp ion microanalysis was applied to the study of the chemistry of macerals in ultrathin sections of a high-volatile A bituminous coal. High-resolution images were obtained by exploiting variations in the intensity of carbon-edge fine structure for contrast. The macerals vitrinite, cutinite, and Sporinite were distinguishable based on the relative intensities of two prominent absorption bands. The lower energy band, at 285.5 eV, was assigned to the transition of the core (1s) electron to the valence π * MO; the absorption intensity correlated with the concentration of aromatic carbon. The higher energy band, near 288 eV, was assigned to a transition of an electron from the core (1s) to a mixed Rydberg/valence (C-H * ) state; the intensity of this band correlated with the concentration of aliphatic carbon. Inertinite's inner-shell spectrum was distinct from those of the other macerals by a relatively intense 1s-π * absorption band, absorption due to transitions to higher energy π * MO's associated with polynuclear aromatics, moderate absorption near 288 eV, and a shoulder at 289.5 eV which was assigned to oxygen containing functionality. At the highest energies, E ∼295 eV, absorptions due to transitions to * states were present in the carbon spectra of each maceral type
George D Cody - One of the best experts on this subject based on the ideXlab platform.
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the application of soft x ray microscopy to the in situ analysis of sporopollenin Sporinite in a rank variable suite of organic rich sediments
Other Information: PBD: [1997], 1997Co-Authors: George D Cody, Robert E Botto, S WirickAbstract:Soft X-ray imaging and carbon near edge absorption fine structure spectroscopy (C-NEXAFS) has been used for the in-situ analysis of Sporinite in a rank variable suite of organic rich sediments extending from recent up to high volatile A bituminous coal. The acquisition of chemically based images (contrast based on the 1s - 1{pi}* transition of unsaturated carbon), revealed a homogeneous chemical structure in the spore exine. C-NEXAFS microanalysis indicates chemical structural evolution in sporopollenin/Sporinite with increases in maturation. The most significant change in the C-NEXAFS spectrum is an increase in unsaturated carbon, presumably aromatic, with rank. The rate of aromatization in Sporinite exceeds that of the surrounding vitrinite. Increases in the concentration of unsaturated carbon are compensated by losses of aliphatic and hydroxylated aliphatic carbon components. Carboxyl groups are present in low and variable concentrations. Absorption due to carboxyl persists in the most mature specimen in this series, a high volatile A rank coal. The reactions which drive sporopollenin chemical structural evolution during diagenesis presumably involve dehydration, Diels-Alder cyclo-addition, and dehydrogenation reactions which ultimately lead to a progressively aromatized bio/geopolymer.
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The application of soft X-ray microscopy to the in-situ analysis of sporopollenin/Sporinite in a rank variable suite of organic rich sediments
1997Co-Authors: George D Cody, Robert E Botto, S WirickAbstract:Soft X-ray imaging and carbon near edge absorption fine structure spectroscopy (C-NEXAFS) has been used for the in-situ analysis of Sporinite in a rank variable suite of organic rich sediments extending from recent up to high volatile A bituminous coal. The acquisition of chemically based images (contrast based on the 1s - 1{pi}* transition of unsaturated carbon), revealed a homogeneous chemical structure in the spore exine. C-NEXAFS microanalysis indicates chemical structural evolution in sporopollenin/Sporinite with increases in maturation. The most significant change in the C-NEXAFS spectrum is an increase in unsaturated carbon, presumably aromatic, with rank. The rate of aromatization in Sporinite exceeds that of the surrounding vitrinite. Increases in the concentration of unsaturated carbon are compensated by losses of aliphatic and hydroxylated aliphatic carbon components. Carboxyl groups are present in low and variable concentrations. Absorption due to carboxyl persists in the most mature specimen in this series, a high volatile A rank coal. The reactions which drive sporopollenin chemical structural evolution during diagenesis presumably involve dehydration, Diels-Alder cyclo-addition, and dehydrogenation reactions which ultimately lead to a progressively aromatized bio/geopolymer.
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the application of soft x ray microscopy to the in situ analysis of Sporinite in coal
International Journal of Coal Geology, 1996Co-Authors: George D Cody, Robert E Botto, S WirickAbstract:Abstract Soft X-ray imaging and carbon near edge absorption fine structure spectroscopy (C-NEXAFS) has been used for the in-situ analysis of Sporinite in a rank-variable suite of organic-rich sediments extending from up to high volatile A bituminous coal. The acquisition of chemically based images (con trast based on the 1s−1π∗ transition of unsaturated carbon), reveals a homogeneous chemical structure in the spore exine. C-NEXAFS microanalysis indicates a chemical structural evolution of the sporopollenin bio/geopolymer with increasing maturation. The most significant change in the C-NEXAFS spectrum is an increase in unsaturated carbon, presumably aromatic, with rank. The rate of “aromatization” in Sporinite in coal exceeds that of the associated vitrinite. Increases in the concentration of unsaturated carbon are paralleled by losses of aliphatic and hydroxylated aliphatic carbon components. Carboxyl groups are present in low and variable concentrations. Absorption due to carboxyl persists in the most mature specimen in this series, a high volatile A bituminous coal. The reactions that drive sporopollenin chemical structural evolution during diagenesis presumably involve sequential dehydration, Diels-Alder cyclo-addition, and dehydrogenation reactions that ultimately lead to a progressively aromatized bio/geopolymer.
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C-NEXAFS Microanalysis and Scanning X-ray Microscopy of Microheterogeneities in a High-Volatile A Bituminous Coal
Energy & Fuels, 1995Co-Authors: George D Cody, Robert E Botto, S. K. Behal, Mark M. Disko, S WirickAbstract:Carbon near-edge X-ray absorp ion microanalysis was applied to the study of the chemistry of macerals in ultrathin sections of a high-volatile A bituminous coal. High-resolution images were obtained by exploiting variations in the intensity of carbon-edge fine structure for contrast. The macerals vitrinite, cutinite, and Sporinite were distinguishable based on the relative intensities of two prominent absorption bands. The lower energy band, at 285.5 eV, was assigned to the transition of the core (1s) electron to the valence π * MO; the absorption intensity correlated with the concentration of aromatic carbon. The higher energy band, near 288 eV, was assigned to a transition of an electron from the core (1s) to a mixed Rydberg/valence (C-H * ) state; the intensity of this band correlated with the concentration of aliphatic carbon. Inertinite's inner-shell spectrum was distinct from those of the other macerals by a relatively intense 1s-π * absorption band, absorption due to transitions to higher energy π * MO's associated with polynuclear aromatics, moderate absorption near 288 eV, and a shoulder at 289.5 eV which was assigned to oxygen containing functionality. At the highest energies, E ∼295 eV, absorptions due to transitions to * states were present in the carbon spectra of each maceral type
Robert E Botto - One of the best experts on this subject based on the ideXlab platform.
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the application of soft x ray microscopy to the in situ analysis of sporopollenin Sporinite in a rank variable suite of organic rich sediments
Other Information: PBD: [1997], 1997Co-Authors: George D Cody, Robert E Botto, S WirickAbstract:Soft X-ray imaging and carbon near edge absorption fine structure spectroscopy (C-NEXAFS) has been used for the in-situ analysis of Sporinite in a rank variable suite of organic rich sediments extending from recent up to high volatile A bituminous coal. The acquisition of chemically based images (contrast based on the 1s - 1{pi}* transition of unsaturated carbon), revealed a homogeneous chemical structure in the spore exine. C-NEXAFS microanalysis indicates chemical structural evolution in sporopollenin/Sporinite with increases in maturation. The most significant change in the C-NEXAFS spectrum is an increase in unsaturated carbon, presumably aromatic, with rank. The rate of aromatization in Sporinite exceeds that of the surrounding vitrinite. Increases in the concentration of unsaturated carbon are compensated by losses of aliphatic and hydroxylated aliphatic carbon components. Carboxyl groups are present in low and variable concentrations. Absorption due to carboxyl persists in the most mature specimen in this series, a high volatile A rank coal. The reactions which drive sporopollenin chemical structural evolution during diagenesis presumably involve dehydration, Diels-Alder cyclo-addition, and dehydrogenation reactions which ultimately lead to a progressively aromatized bio/geopolymer.
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The application of soft X-ray microscopy to the in-situ analysis of sporopollenin/Sporinite in a rank variable suite of organic rich sediments
1997Co-Authors: George D Cody, Robert E Botto, S WirickAbstract:Soft X-ray imaging and carbon near edge absorption fine structure spectroscopy (C-NEXAFS) has been used for the in-situ analysis of Sporinite in a rank variable suite of organic rich sediments extending from recent up to high volatile A bituminous coal. The acquisition of chemically based images (contrast based on the 1s - 1{pi}* transition of unsaturated carbon), revealed a homogeneous chemical structure in the spore exine. C-NEXAFS microanalysis indicates chemical structural evolution in sporopollenin/Sporinite with increases in maturation. The most significant change in the C-NEXAFS spectrum is an increase in unsaturated carbon, presumably aromatic, with rank. The rate of aromatization in Sporinite exceeds that of the surrounding vitrinite. Increases in the concentration of unsaturated carbon are compensated by losses of aliphatic and hydroxylated aliphatic carbon components. Carboxyl groups are present in low and variable concentrations. Absorption due to carboxyl persists in the most mature specimen in this series, a high volatile A rank coal. The reactions which drive sporopollenin chemical structural evolution during diagenesis presumably involve dehydration, Diels-Alder cyclo-addition, and dehydrogenation reactions which ultimately lead to a progressively aromatized bio/geopolymer.
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the application of soft x ray microscopy to the in situ analysis of Sporinite in coal
International Journal of Coal Geology, 1996Co-Authors: George D Cody, Robert E Botto, S WirickAbstract:Abstract Soft X-ray imaging and carbon near edge absorption fine structure spectroscopy (C-NEXAFS) has been used for the in-situ analysis of Sporinite in a rank-variable suite of organic-rich sediments extending from up to high volatile A bituminous coal. The acquisition of chemically based images (con trast based on the 1s−1π∗ transition of unsaturated carbon), reveals a homogeneous chemical structure in the spore exine. C-NEXAFS microanalysis indicates a chemical structural evolution of the sporopollenin bio/geopolymer with increasing maturation. The most significant change in the C-NEXAFS spectrum is an increase in unsaturated carbon, presumably aromatic, with rank. The rate of “aromatization” in Sporinite in coal exceeds that of the associated vitrinite. Increases in the concentration of unsaturated carbon are paralleled by losses of aliphatic and hydroxylated aliphatic carbon components. Carboxyl groups are present in low and variable concentrations. Absorption due to carboxyl persists in the most mature specimen in this series, a high volatile A bituminous coal. The reactions that drive sporopollenin chemical structural evolution during diagenesis presumably involve sequential dehydration, Diels-Alder cyclo-addition, and dehydrogenation reactions that ultimately lead to a progressively aromatized bio/geopolymer.
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C-NEXAFS Microanalysis and Scanning X-ray Microscopy of Microheterogeneities in a High-Volatile A Bituminous Coal
Energy & Fuels, 1995Co-Authors: George D Cody, Robert E Botto, S. K. Behal, Mark M. Disko, S WirickAbstract:Carbon near-edge X-ray absorp ion microanalysis was applied to the study of the chemistry of macerals in ultrathin sections of a high-volatile A bituminous coal. High-resolution images were obtained by exploiting variations in the intensity of carbon-edge fine structure for contrast. The macerals vitrinite, cutinite, and Sporinite were distinguishable based on the relative intensities of two prominent absorption bands. The lower energy band, at 285.5 eV, was assigned to the transition of the core (1s) electron to the valence π * MO; the absorption intensity correlated with the concentration of aromatic carbon. The higher energy band, near 288 eV, was assigned to a transition of an electron from the core (1s) to a mixed Rydberg/valence (C-H * ) state; the intensity of this band correlated with the concentration of aliphatic carbon. Inertinite's inner-shell spectrum was distinct from those of the other macerals by a relatively intense 1s-π * absorption band, absorption due to transitions to higher energy π * MO's associated with polynuclear aromatics, moderate absorption near 288 eV, and a shoulder at 289.5 eV which was assigned to oxygen containing functionality. At the highest energies, E ∼295 eV, absorptions due to transitions to * states were present in the carbon spectra of each maceral type
John C. Crelling - One of the best experts on this subject based on the ideXlab platform.
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Classification of torbanite and cannel coal: I. Insights from petrographic analysis of density fractions
International Journal of Coal Geology, 1999Co-Authors: Michael A Kruge, John C. Crelling, David F BensleyAbstract:Torbanite and cannel coal are considered to be coals because of their low mineral content and overall physical morphology. However, the texture and composition of the organic matter in torbanite and cannel coal are similar to the kerogen occurring in oil shales and lacustrine source rocks. Therefore, understanding the nature and origin of organic components in torbanite and cannel coal is of significance in the study of kerogen and petroleum formation. In this research, a set of torbanites and cannel coals from different locations throughout the world were petrographically characterized and processed using a density gradient centrifugation (DGC) technique. Microscopically, the torbanite and cannel coal are composed of coarser maceral particles set in a fine-grained to amorphous groundmass. The groundmass is a mixture of more than one type of substance and accounts for 10 to 80% (by volume) of the torbanites and cannel coals. Botryococcus-related alginite is the most characteristic component of the torbanite. While Sporinite typically is the main phytoclast in the cannel coals, in most cases the groundmass is volumetrically the dominant component, determining the overall character of the sample. This observation calls into question the traditional practice of classifying such coals using the alginite to Sporinite ratio. Variations in composition, texture and fluorescence permits the recognition of three different types of groundmass: lamalginitic, bituminitic and vitrinitic. High purity alginite, Sporinite, vitrinite and varieties of groundmass were separated using the DGC technique. The distribution of density fractions closely reflects the petrographic composition of the various torbanites and cannel coals. Distinct peaks on the density profiles represent the major organic components and peak magnitudes are functions of the percentage of the components, demonstrating that the density gradient profiles can be used to distinguish the different types of torbanite and cannel coal. The separation data also indicate a gradual shift towards higher density from lamalginitic to bituminitic to vitrinitic groundmass.
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Fluorescence intensity and alteration of coal macerals and their relation to coalification
Organic Geochemistry, 1993Co-Authors: John C. Crelling, Yi ZhouAbstract:Abstract Based on the measurements of fluorescence intensity and alteration on a rank series of coals from China, the process of coalification ranging from peat to early volatile bituminous coal can be divided into four rank stages. The boundaries between adjacent stages lie at the vitrinite reflectances of 0.30%, 0.55% and in the range of 0.80–0.90% R m, where striking fluorescence changes or jumps take place. The jump at 0.3% R m, which has not been reported before, marks the boundary between soft and hard brown coals. The other boundaries correspond to the first and second coalification jumps described by Teichmuller and Durand (1983), and can be compared with the oil birth line and maximum generation. Fluorescence intensity of both huminites/vitrinites and Sporinites generally decreases with increasing rank. Based on the correlation equations between vitrinite reflectance and fluorescence intensity established in this study, it is possible to predict coal rank or thermal maturity of organic matter with fluorescence intensity analysis. While the huminites/vitrinites and Sporinites display a similar alteration rank trend: from negative, through positive and dual and negative again, at any given rank, the alteration patterns of Sporinites and vitrinites are different from each other. With increasing rank, the change of alteration pattern of the huminites/vitrinites always takes place earlier than that of the Sporinites.
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Characterization and Selective Removal of Organic Sulfur from IIIinois Basin Coals
Coal Preparation, 1992Co-Authors: S R Palmer, Edwin J. Hippo, Michael A Kruge, John C. CrellingAbstract:In order to develop appropriate desulfurization strategies, the organic sulfur species and their distribution in coal need to be characterized. Peroxyacetic acid oxidation has been developed to render coal soluble, allowing for the subsequent GC-FID/FPD and GC-MS analysis of sulfur compounds. Four Illinois Basin coals and samples of Sporinite, vitrinite and semifusinite isolated from them have been examined. Between 20 and 50% of the organic sulfur in these coals is associated with relatively few compounds detected in the volatile oxidation products. Of these, methylsulfonic acid is the most abundant, which, from model compound studies, results from oxidation of either methyl disulfide or simple thiophene structures in the coals. Although the species detected are commonly occurring among the majority of the coal and maceral fractions, their distribution varies considerably from sample to sample. By fractionating the oxidation products, a fraction was obtained that had a sulfur content of 18%. This fractio...
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Chemical structure of bituminous coal and its constituting maceral fractions as revealed by flash pyrolysis
Energy & Fuels, 1992Co-Authors: Jan W. De Leeuw, John C. CrellingAbstract:To study the relationships between the chemical structures of coals, coal macerals, and their precursors (plant tissues), a high-volatile bituminous Upper Carboniferous coal and its constituting maceral fractions, cutinite, resinite, Sporinite, vitrinite, pseudovitrinite, semifusinite, and fusinite, were investigated by Curie point pyrolysis−gas chromatography and Curie point pyrolysis−gas chromatography−mass spectrometry
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Desulfurization of single coal macerals
Fuel Processing Technology, 1991Co-Authors: Edwin J. Hippo, John C. CrellingAbstract:Abstract The main objective of this study is to investigate the desulfurization behavior of individual coal macerals. The Sporinite and vitrinite macerals which contain most of the organic sulfur in coal are more reactive toward desulfurization processes than any of the other materials that were studied. They also give the highest desulfurization levels. Since they are more reactive than whole coals or floated samples, the other constituents in the coal matrix must reduce sulfur removals. This phenomenon has not been reported previously. It implies that the inertinite macerals may behave in a manner similar to activated charcoal and chemically absorb copious amounts of sulfur during the desulfurization processes. The practical result of this phenomenon is that selection of coals on the basis of maceral composition could be necessary to optimize thermal-chemical desulfurization.
Michael A Kruge - One of the best experts on this subject based on the ideXlab platform.
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Classification of torbanite and cannel coal: II. Insights from pyrolysis-GC/MS and multivariate statistical analysis
International Journal of Coal Geology, 1999Co-Authors: Michael A KrugeAbstract:Abstract Petrographic and megascopic criteria have traditionally been used as the basis for the classification of torbanite and cannel coal. For this study, it was hypothesized that modern analytical organic geochemical and multivariate statistical techniques could provide an alternative approach. Towards this end, the demineralized residues of 14 torbanite (rich in Botryococcus-related alginite) and cannel (essentially, rich in organic groundmass and/or Sporinite) coal samples were analyzed by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Cluster analysis performed on the Py-GC/MS data clearly distinguished the torbanite from the cannel coal, demonstrating a consistency between the chemical properties and the petrographic composition. All the torbanite samples group into one cluster, their pyrolyzates having an overwhelming predominance of straight chain hydrocarbons, a characteristic typical of Botryococcus. The presence of the C9–C26 n-α,ω-alkadiene series is the key feature distinguishing the torbanites from the other samples. The cannel coals exhibit more chemical diversity, reflecting their greater variability in petrographic composition. The Breckinridge cannel, dominated by a highly aliphatic lamalginitic groundmass, chemically fits the torbanite category. The bituminitic groundmass-dominated cannel coals fall into a cannel sub-cluster, their pyrolyzates having a characteristic predominance of n-alk-1-enes and n-alkanes (particularly the long-chain homologues), with no detectable alkadienes. The vitrinitic groundmass-dominated Ohio Linton cannel and the Sporinite-rich Canadian Melville Island cannel are readily distinguishable from the other cannels by the relatively abundant aromatic and phenolic compounds in their pyrolyzates. The internal distribution patterns of alkylaromatic and alkylphenolic isomers are shown to be less significant in the classification of this sample set. Multivariate statistical analysis of the pyrolysis data not only successfully discriminated torbanites from cannel coals, but recognized subtler differences between the examples of these two coal types, in substantial agreement with the petrographic characterization. As such, these methods can substitute for or supplement the traditional microscope-based approach.
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Classification of torbanite and cannel coal: I. Insights from petrographic analysis of density fractions
International Journal of Coal Geology, 1999Co-Authors: Michael A Kruge, John C. Crelling, David F BensleyAbstract:Torbanite and cannel coal are considered to be coals because of their low mineral content and overall physical morphology. However, the texture and composition of the organic matter in torbanite and cannel coal are similar to the kerogen occurring in oil shales and lacustrine source rocks. Therefore, understanding the nature and origin of organic components in torbanite and cannel coal is of significance in the study of kerogen and petroleum formation. In this research, a set of torbanites and cannel coals from different locations throughout the world were petrographically characterized and processed using a density gradient centrifugation (DGC) technique. Microscopically, the torbanite and cannel coal are composed of coarser maceral particles set in a fine-grained to amorphous groundmass. The groundmass is a mixture of more than one type of substance and accounts for 10 to 80% (by volume) of the torbanites and cannel coals. Botryococcus-related alginite is the most characteristic component of the torbanite. While Sporinite typically is the main phytoclast in the cannel coals, in most cases the groundmass is volumetrically the dominant component, determining the overall character of the sample. This observation calls into question the traditional practice of classifying such coals using the alginite to Sporinite ratio. Variations in composition, texture and fluorescence permits the recognition of three different types of groundmass: lamalginitic, bituminitic and vitrinitic. High purity alginite, Sporinite, vitrinite and varieties of groundmass were separated using the DGC technique. The distribution of density fractions closely reflects the petrographic composition of the various torbanites and cannel coals. Distinct peaks on the density profiles represent the major organic components and peak magnitudes are functions of the percentage of the components, demonstrating that the density gradient profiles can be used to distinguish the different types of torbanite and cannel coal. The separation data also indicate a gradual shift towards higher density from lamalginitic to bituminitic to vitrinitic groundmass.
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Characterization and Selective Removal of Organic Sulfur from IIIinois Basin Coals
Coal Preparation, 1992Co-Authors: S R Palmer, Edwin J. Hippo, Michael A Kruge, John C. CrellingAbstract:In order to develop appropriate desulfurization strategies, the organic sulfur species and their distribution in coal need to be characterized. Peroxyacetic acid oxidation has been developed to render coal soluble, allowing for the subsequent GC-FID/FPD and GC-MS analysis of sulfur compounds. Four Illinois Basin coals and samples of Sporinite, vitrinite and semifusinite isolated from them have been examined. Between 20 and 50% of the organic sulfur in these coals is associated with relatively few compounds detected in the volatile oxidation products. Of these, methylsulfonic acid is the most abundant, which, from model compound studies, results from oxidation of either methyl disulfide or simple thiophene structures in the coals. Although the species detected are commonly occurring among the majority of the coal and maceral fractions, their distribution varies considerably from sample to sample. By fractionating the oxidation products, a fraction was obtained that had a sulfur content of 18%. This fractio...
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aspects of Sporinite chemistry
Organic Geochemistry, 1991Co-Authors: Michael A Kruge, Edwin J. Hippo, John C. Crelling, S R PalmerAbstract:Abstract With the recent advent of the ability to separate coal into maceral concentrates of high purity, the individual constituents of coal can now be analyzed separately, without their mutual interference, giving a much better understanding of the macromolecular structure of coal. The Sporinites from two Pennsylvanian age coal samples (Illinois Basin, U.S.A.) were studied, one from a vitrinite-rich high-volatile bituminous coal, the other from a liptinite-rich high-volatile butuminous coal of slightly higher rank. Sporinites were isolated from each coal by density gradient centrifugation. The Sporinite of the vitrinite-rich coal was compared chemically and petrographically with the parent coal and with the Sporinite of the liptinite-rich coal. The fluorescence spectrum of the Sporinite from the liptinite-rich coal is shifted to the red end of the spectrum, which may be accounted for by the somewhat higher rank of the sample and/or by differences in the original assemblage of spores. The lack of chemical differences between the extracts of the Sporinite and its whole coal reinforce the concept of bitumen as an homogeneous mobile phase pervading the coal. Thus, extract chemistry seems an unsuitable technique for distinguishing between macerals from the same coal. Hopane and sterane distributions in the Sporinite and parent coal pyrolyzates are very similar, but the two materials can be readily distinguished by the distribution of tetracyclic diterpanes of the phyllocladane type, which are biological marker compounds derived from higher plant material. Overall, the Sporinite is considerably more paraffinic in character and has a greater preponderance of straight-chain alkane moieties than the coal as a whole. In the case of the vitrinite-rich coal, the whole-coal structure appears significantly more polyaromatic than the Sporinite. The distributions of thiophenic compounds differ in the pyrolyzates of the two materials. The Sporinite from the liptinite-rich coal is even less polycondensed than the Sporinite from the vitrinite-rich sample. The chemical and petrographic differences of the two Sporinites probably reflect the different assemblages of spores in the original peats and their different diagenetic histories.
