Gill, GR
1988-1987
Characterization of US Lignites by Pyrolysis Mass Spectrometry and Multivariate Analysis
Metcalf, G.S.; Windig, W.; Gill, G.R. and Meuzelaar, H.L.C.
International Journal of Coal Geology, 7, 245-268, 1987. 23 pgs. Funded by US Department of Energy, Phillips Petroleum, and State of Utah.
Sixteen Texas (Gulf Province) lignite samples and six Montana and Wyoming (Northern Plains province) lignite samples were obtained from the Penn state coal sample collection and analyzed in triplicate by pyrolysis mass spectrometrey (Py-MS) using Curie-point pyrolysis (equilibrium temp. 610ºC) in combination with low voltage (12 eV) electron ionization. The spectra obtained were evaluated by means of factor analysis, followed by discriminant analysis using only factors with eigenvalue >= 1 and regarding each set of triplicate spectra as a separate category. The discriminant analysis results showed a definite separation between lignites from the two provinces as well as some clustering of samples from the same seam field or region. Six additional lignite samples obtained from an independent source and representing other regions of the Gulf province were found to cluster with the Texas lignite samples when treated as "unknowns" in the discriminant analysis procedure.
Chemical interpretation of the spectral differences underlying the clustering behavior of the lignite samples in the discriminant analysis procedure was attempted using a newly developed, unsupervised numerical extraction method for chemical components in complex spectra. This procedure the Variance Diagram (VARDIA) technique revealed the presence of six major chemical component axes. Examination of the spectral patterns corresponding to these component axes showed a softwood lignin-like component (high in Northern Plains lignites) and an aliphatic (algal?) hydrocarbon component (high in Gulf lignites) to be primarily responsible for the differences between the two provinces. In addition, two biomarker patterns, namely a terpenoid resin-like component and an unknown component, were shown to be highly characteristic for the Northern Plains and Gulf Province lignites respectively. Two other component axes were found to consist largely of sulfur-containing ion series, one of which appeared to represent an obvious marine influence on the South Texas region of the Gulf province.
Furthermore, a set of seventeen conventional coal parameters, including petrographic, ultimate and proximate analysis data as well as sulfur content, calorific value and vitrinite reflectance, obtained from the Penn State coal data bank on all twenty-two lignite samples, was also submitted to factor analysis. Comparison of the scores of the first two factors from this set with the scores of the first two discriminant functions of the Py-MS data set revealed an overall similarity in clustering behavior of the lignite samples from the two provinces. Subsequently, canonical variate analysis was used to rotate both the conventional and Py-MS data sets to a common set of vectors describing and correlating ("overlapping") portions of both data sets. Examination of the first two pairs of canonical variate functions revealed strong correlations between the conventional data and the Py-MS data, e.g., with regard to aliphatic vs. aromatic or hydrocarbon tendencies, as well as sulfur containing moieties. This enabled a final, tentative synthesis of all the lignite data into several highly simplified schemes relating compositional aspects to depositional environments.
Effects of Low Temperature Air Oxidation (Weathering) Reactions on the Pyrolysis of Mass Spectra of US Coals
Jakab, E.; Hoesterey, B.L.; Windig, W.; Gill, G.R. and Meuzelaar, H.L.C.
Fuel, 67, (1), 73-79, 1988. 6 pgs. Funded by US Department of Energy and Utah Power and Light.
Two high volatile bituminous coals (Upper Freeport and Hiawatha seams), a subbituminous coal (Adaville seam) were used to investigate the effect of low temperature air oxidation ("weathering") on the yield and composition of vacuum pyrolysis products. Fresh coal samples were exposed to air at 80º and 100ºC for up to 10 days under controlled laboratory conditions. Curie-point pyrolysis mass spectrometry combined with computerized data analysis was applied to study the weathering induced changes in a series of samples weathered for various lengths of time. It was found that the abundance of small oxygen-containing molecules such as carbon monoxide, carbon dioxide and aliphatic carboxylic acids increased in the pyrolysate of all samples, whereas phenols and dihydroxybenzenes showed decreased yields, especially in the two lowest rank coals. Besides phenols, alkylnaphthalenes and alkyltetralins showed decreased abundances in the pyrolysis mass spectra of the two high volatile bituminous coals. An attempt is made to explain the difference in pyrolysis patterns observed before and after weathering experiments in terms of underlying structural changes.
Gill, GR
1988-1987
Characterization of US Lignites by Pyrolysis Mass Spectrometry and Multivariate Analysis
Metcalf, G.S.; Windig, W.; Gill, G.R. and Meuzelaar, H.L.C.
International Journal of Coal Geology, 7, 245-268, 1987. 23 pgs. Funded by US Department of Energy, Phillips Petroleum, and State of Utah.
Sixteen Texas (Gulf Province) lignite samples and six Montana and Wyoming (Northern Plains province) lignite samples were obtained from the Penn state coal sample collection and analyzed in triplicate by pyrolysis mass spectrometrey (Py-MS) using Curie-point pyrolysis (equilibrium temp. 610ºC) in combination with low voltage (12 eV) electron ionization. The spectra obtained were evaluated by means of factor analysis, followed by discriminant analysis using only factors with eigenvalue >= 1 and regarding each set of triplicate spectra as a separate category. The discriminant analysis results showed a definite separation between lignites from the two provinces as well as some clustering of samples from the same seam field or region. Six additional lignite samples obtained from an independent source and representing other regions of the Gulf province were found to cluster with the Texas lignite samples when treated as "unknowns" in the discriminant analysis procedure.
Chemical interpretation of the spectral differences underlying the clustering behavior of the lignite samples in the discriminant analysis procedure was attempted using a newly developed, unsupervised numerical extraction method for chemical components in complex spectra. This procedure the Variance Diagram (VARDIA) technique revealed the presence of six major chemical component axes. Examination of the spectral patterns corresponding to these component axes showed a softwood lignin-like component (high in Northern Plains lignites) and an aliphatic (algal?) hydrocarbon component (high in Gulf lignites) to be primarily responsible for the differences between the two provinces. In addition, two biomarker patterns, namely a terpenoid resin-like component and an unknown component, were shown to be highly characteristic for the Northern Plains and Gulf Province lignites respectively. Two other component axes were found to consist largely of sulfur-containing ion series, one of which appeared to represent an obvious marine influence on the South Texas region of the Gulf province.
Furthermore, a set of seventeen conventional coal parameters, including petrographic, ultimate and proximate analysis data as well as sulfur content, calorific value and vitrinite reflectance, obtained from the Penn State coal data bank on all twenty-two lignite samples, was also submitted to factor analysis. Comparison of the scores of the first two factors from this set with the scores of the first two discriminant functions of the Py-MS data set revealed an overall similarity in clustering behavior of the lignite samples from the two provinces. Subsequently, canonical variate analysis was used to rotate both the conventional and Py-MS data sets to a common set of vectors describing and correlating ("overlapping") portions of both data sets. Examination of the first two pairs of canonical variate functions revealed strong correlations between the conventional data and the Py-MS data, e.g., with regard to aliphatic vs. aromatic or hydrocarbon tendencies, as well as sulfur containing moieties. This enabled a final, tentative synthesis of all the lignite data into several highly simplified schemes relating compositional aspects to depositional environments.
Effects of Low Temperature Air Oxidation (Weathering) Reactions on the Pyrolysis of Mass Spectra of US Coals
Jakab, E.; Hoesterey, B.L.; Windig, W.; Gill, G.R. and Meuzelaar, H.L.C.
Fuel, 67, (1), 73-79, 1988. 6 pgs. Funded by US Department of Energy and Utah Power and Light.
Two high volatile bituminous coals (Upper Freeport and Hiawatha seams), a subbituminous coal (Adaville seam) were used to investigate the effect of low temperature air oxidation ("weathering") on the yield and composition of vacuum pyrolysis products. Fresh coal samples were exposed to air at 80º and 100ºC for up to 10 days under controlled laboratory conditions. Curie-point pyrolysis mass spectrometry combined with computerized data analysis was applied to study the weathering induced changes in a series of samples weathered for various lengths of time. It was found that the abundance of small oxygen-containing molecules such as carbon monoxide, carbon dioxide and aliphatic carboxylic acids increased in the pyrolysate of all samples, whereas phenols and dihydroxybenzenes showed decreased yields, especially in the two lowest rank coals. Besides phenols, alkylnaphthalenes and alkyltetralins showed decreased abundances in the pyrolysis mass spectra of the two high volatile bituminous coals. An attempt is made to explain the difference in pyrolysis patterns observed before and after weathering experiments in terms of underlying structural changes.