Davis, BH
1994
The Effect of the Mobile Component on the Liquefaction Characteristic of Western Kentucky Coals
Keogh, R.A.; Hardy, R.H.; Taghizadeh, K.; Meuzelaar, H.L.C. and Davis, B.H.
Fuel Processing Technology, 37:33-52, 1994. Funded by US Department of Energy.
The mobile component of western Kentucky coals were extracted and analyzed by conventional methods and Curie-point mass spectroscopy. The liquefaction of the parent coals, extracted coals, and blends of the extracted coals plus mobile components indicated that the absence of the mobile component generally decreases the observed conversions obtained. The results also show that, in general, blending the mobile component and extracted coal also produces lower conversions than those obtained from the parent coal. These data suggest that the location of the mobile component in the pore structure of the coal is as important as the presence of the mobile component in coal conversion.
1993
The Effect of the Mobile Component on the Liquefaction Characteristic of Western Kentucky Coals
Keogh, R.A.; Hardy, R.H.; Taghizadeh, K.; Meuzelaar, H.L.C. and Davis, B.H.
Fuel Processing Technology, 1993 (in press). Funded by US Department of Energy.
The mobile component of western Kentucky coals were extracted and analyzed by conventional methods and Curie-point mass spectroscopy. The liquefaction of the parent coals, extracted coals, and blends of the extracted coals plus mobile components indicated that the absence of the mobile component generally decreases the observed conversions obtained. The results also show that, in general, blending the mobile component and extracted coal also produces lower conversions than those obtained from the parent coal. These data suggest that the location of the mobile component in the pore structure of the coal is as important as the presence of the mobile component in coal conversion.
1990
Comparison of Low-Voltage Electron Ionization and Field Ionization Mass Spectra of Coal-Derived Liquids from the Wilsonville Pilot Plant
Taghizadeh, K.; Hardy, R.H., Davis, B.H. and Meuzelaar, H.L.C.
Fuel Processing Technology, 1990 (In press). Funded by Consortium for Fossil Fuel Liquifaction Science, Commonwealth of Kentucky, Kentucky Energy Cabinet and US Department of Energy.
Low voltage - Electron Ionization (LV-EI) and Field ionization (FI) mass spectra of coal-derived liquids (CDLs) obtained from the Wilsonville Coal liquefaction pilot plant before and after hydrotreatment were compared. LV-EIMS (12 eV) analysis of Wilsonville CDL'S before and after hydrotreatment produces very similar spectral patterns as obtained by FIMS. This is especially true for the more highly aromatic hydrotreater feed samples since the hydroaromatic compounds that dominate the hydrotreater product sampler tend to fragment more under LV-MS conditions. Canonical variate analysis confirms that the mass spectral patterns produced by both techniques are highly correlated with the exception of the higher mass range (above m/z 300) that is severely under-represented in the LV-EIMS patterns, due to lower inlet temperatures and to mass discrimination effects in quadrupole MS systems. Furthermore, in spite of the highly complex nature of the original spectral profiles, use of multivariate statistical analysis techniques, such as factor analysis and canonical correlation analysis, enables "numerical extraction" of simplified spectral patterns which can be tentatively interpreted in terms of chemical components or compound series.
1989
Investigation of the Molecular Structure of Organic Sulfur in Coal by XAFS Spectroscopy
Huffman, G.P.; Huggins, F.E.; Mitra, S.; Shah, N.; Pugmire, R.J.; Davis, B.H.; Lytle, F.W. and Greegor, R.B.
Energy & Fuels, 3, 200, 1989. Funded by US Department of Energy.
X-ray absorption fine structure (XAFS) spectroscopy has been used to investigate the molecular structure of organic sulfur in a suite of maceral separates and in several biodesulfurized and extracted coal specimens. For most samples, the X-ray absorption near-edge structure (XANES) exhibits sharp peaks just above the absorption edge that are characteristic of s Æ p transitions of compounds containing an aromatically bound sulfur atom and a broad, structured maximum at somewhat higher energies. The latter maximum is believed to arise from resonant backscattering of photoelectrons by carbon atoms 3.5-4.1 Å from the sulfur atom and possibly from s Æ p transitions of sulfur bonded to oxygen. The radial structure functions derived by Fourier analysis of the EXAFS exhibit peaks at distances that are compatible with the first three neighbor shells surrounding an aromatically bound sulfur atom.
1988-1987
Off-Line Process Monitoring of Coal-Derived Liquid Fuels by Computer Assisted Low Mass Spectrometry
Taghizadeh, K.; Davis, B.H.; Windig, W. and Meuzelaar, H.L.C.
Fossil Fuel Analysis by Mass Spectrometry, 1988, T.A. Milne, (ed.), in press. Funded by Commonwealth of Kentucky, Kentucky Energy Cabinet, US Department of Energy and Consortium For Fossil Fuel Liquefaction Science.
Compositional changes of Coal-Derived Liquids (CDL's) during hydrotreatment on fixed bed catalysts can be investigated by Low Voltage (12 eV) MS in combination with multivariate analysis without chromatographic preseparation. Low voltage (12 eV) MS data were obtained and compared under two inlet conditions; MS inlet (1) at ambient temperatures and (2) preheated to about 200ºC. The major trend found in both data sets by Factor analysis was the hydrotreatment effect, namely hydroaromatic (hydrotreater product) vs. aromatic (hydrotreater feed) compounds. A second "time + temperature" trend which reflected the aging of the catalyst as well as the temperature of the hydrotreater reactor was only obtained under ambient inlet temperature conditions. Numerically extracted spectra along the second trend show that more low molecular weight components were found early in the process and also at lower temperatures, whereas more of the higher molecular weight components, primarily alkyl substituted polynuclear aromatics, were obtained later in the process at higher temperatures of the hydrotreater.
A supercritical fluid chromatographic system was constructed to provide separations and fraction collection on a semipreparative scale. Columns packed with silica materials of intermediate particle sizes (30-70 mm) were used to allow dynamic pressure programming with minimum pressure drop of the CO2 mobile phase along the length of the column. A variety of complex coal- and petroleum-derived polycyclic aromatic compound mixtures were fractionated according to the number of aromatic rings using columns packed with an NH2- modified stationary phase bonded on silica particles. The CO2 mobile phase was programmed with an alternating series of linear pressure ramps and isobaric intervals to effect even peak spacing and near base line resolution of compounds of differing ring number in a coal tar. A solvent refined coal heavy distillate and a crude oil were similarly fractionated. Effluents were monitored with an ultraviolet spectrophotometer at 254 nm and a flame ionization detector while fractions were collected in pressurized vessels for subsequent analysis by capillary gas chromatography. Sample capacities of up to 20 mg were possible with this system.
Investigation of the Atomic and Physical Structure of Organic and Inorganic Sulfur in Coal
Huffman, G.P.; Huggins, F.E.; Shah, N.; Bhattacharyya, D.; Pugmire, R.J.; Davis, B.H.; Lytle, F.W. and Greegor, R.B.
Processing and Utilization of High Sulfur Coals II, 3-12, 1987. 10 pgs. Funded by US Department of Energy.
A complete description of the microstructure and molecular state of sulfur in coal can be achieved by combining several experimental techniques. For quantitative analysis of pyrite and its transformation products resulting from oxidative or reductive processes, Fe Mossbauer spectroscopy appears to be the best technique available. Computer-controlled scanning electron microscopy (CCSEM) provides an excellent method of measuring the particle size distributions of pyrite and its transformation products, information that is critical in physical and biological cleaning processes. Finally, it is shown that X-ray absorption fine structure spectroscopy, usually referred to as EXAFS spectroscopy, is capable of determining the atomic structure of organic or other forms of sulfur in coal and coal derivatives. EXAFS data will be presented on organic sulfur in standard compounds, maceral separates, and microbially desulfurized coal.
Comparison of Low Voltage and Field Ionization Mass Spectra of Coal Derived Liquids from the Wilsonville Plant
Taghizadeh, K.; Hardy, R.H.; Davis, B.H. and Meuzelaar, H.L.C.
Submitted to Analytical Chemistry, 1988. Funded by Commonwealth of Kentucky, Kentucky Energy Cabinet, and US Department of Energy.
Low voltage (LV) and field ionization (FI) mass spectral of coal-derived liquids (CDL) before and after hydrotreatment from the Wilsonville Coal liquefaction pilot plant were compared. LV-MS (12eV) analysis of Wilsonville CDL'S before and after hydrotreatment produces very similar spectral patterns as obtained by FI-MS. This is especially true for the more highly aromatic hydrotreater feed samples since hydroaromatic compounds tend to fragment more under LV-MS conditions. Canonical variate analysis confirms that the mass spectral patterns produced by both techniques are highly correlated with the exception of the higher mass range (above m/z 300) that appears to be underrepresented in the LV-MS patterns, primarily as a result of lower inlet temperatures. Furthermore, in spite of the highly complex nature of the original spectral profiles, use of multivariate statistical analysis techniques, such as factor analysis and canonical correlation analysis, enables "numerical extraction" of simplified spectral patterns which can be tentatively interpreted in terms of chemical components or compound series.
Hydrotreatment Effects on Wilsonville Coal Liquids; Computer-Assisted Evaluation of Multisource Analytical Data
Taghizadeh, K.; Davis, B.H. and Meuzelaar, H.L.C.
ACS Preprint, 32, 4, 1987, New Orleans. Funded by Commonwealth of Kentucky, Kentucky, Energy Cabinet, US Department of Energy and Consortium For Fossil Fuel Liquefaction Science.
Due to the high complexity of coal-derived liquids no single analytical method provides adequate compositional information. In this study, low voltage MS data on Wilsonville coal liquid samples from a single 67-day run in the ITSL mode using Illinois #6 coal were combined with available H and C-13 NMR data, as well as conventional characterization data, by means of computerized multivariate analysis techniques, viz. canonical correlation analysis. The low voltage MS data revealed a high degree of correlation with the NMR data as well as the conventional data. As expected, the hydrotreatment step is characterized by an increase in the relative abundance of hydroaromatic compounds accompanied by a decreased abundance of condensed aromatic hydrocarbons, as well as a strong reduction in heteroatomic compounds. Moreover, the combined effect of catalyst aging and reactor temperature is a decrease in the relative abundance of lower molecular weight-compounds and more reactive chemical structures (e.g., alkyltetralins). Furthermore, during the later stages of the run nitrogen- and sulfur-containing moieties appear to be less efficiently removed in the hydrotreatment step.
EXAFS Investigation of Organic Sulfur in Coal
Huffman, G.P.; Huggins, F.E.; Shah, N.; Bhattacharyya, D.; Pugmire, R.J.; Davis, B.H.; Lytle, F.W. and Greegor, R.B.
ACS Div. of Fuel Chemistry, 33, (1), 200-208, 1988. 9 pgs. Funded by US Department of Energy.
EXAFS spectroscopy is shown to be a very promising technique for investigating the molecular structure of organically bound sulfur in coal and coal derivatives. The current paper presents sulfur K-shell EXAFS results for a number of a maceral separates prepared by density gradient centrifugation and for several biodesulfurized coals. Both the near-edge structure and the radial structure functions exhibit some similarities to dibenzothiophene. However, a broad peak occurs in the XANES region of the coal spectra that is not observed for the molecular structures usually ascribed to organic sulfur in coal. This is believed to arise from resonant photoelectron scattering from second and third nearest neighbor carbon shells and from sulfur bonded to oxygen.
Davis, BH
1994
The Effect of the Mobile Component on the Liquefaction Characteristic of Western Kentucky Coals
Keogh, R.A.; Hardy, R.H.; Taghizadeh, K.; Meuzelaar, H.L.C. and Davis, B.H.
Fuel Processing Technology, 37:33-52, 1994. Funded by US Department of Energy.
The mobile component of western Kentucky coals were extracted and analyzed by conventional methods and Curie-point mass spectroscopy. The liquefaction of the parent coals, extracted coals, and blends of the extracted coals plus mobile components indicated that the absence of the mobile component generally decreases the observed conversions obtained. The results also show that, in general, blending the mobile component and extracted coal also produces lower conversions than those obtained from the parent coal. These data suggest that the location of the mobile component in the pore structure of the coal is as important as the presence of the mobile component in coal conversion.
1993
The Effect of the Mobile Component on the Liquefaction Characteristic of Western Kentucky Coals
Keogh, R.A.; Hardy, R.H.; Taghizadeh, K.; Meuzelaar, H.L.C. and Davis, B.H.
Fuel Processing Technology, 1993 (in press). Funded by US Department of Energy.
The mobile component of western Kentucky coals were extracted and analyzed by conventional methods and Curie-point mass spectroscopy. The liquefaction of the parent coals, extracted coals, and blends of the extracted coals plus mobile components indicated that the absence of the mobile component generally decreases the observed conversions obtained. The results also show that, in general, blending the mobile component and extracted coal also produces lower conversions than those obtained from the parent coal. These data suggest that the location of the mobile component in the pore structure of the coal is as important as the presence of the mobile component in coal conversion.
1990
Comparison of Low-Voltage Electron Ionization and Field Ionization Mass Spectra of Coal-Derived Liquids from the Wilsonville Pilot Plant
Taghizadeh, K.; Hardy, R.H., Davis, B.H. and Meuzelaar, H.L.C.
Fuel Processing Technology, 1990 (In press). Funded by Consortium for Fossil Fuel Liquifaction Science, Commonwealth of Kentucky, Kentucky Energy Cabinet and US Department of Energy.
Low voltage - Electron Ionization (LV-EI) and Field ionization (FI) mass spectra of coal-derived liquids (CDLs) obtained from the Wilsonville Coal liquefaction pilot plant before and after hydrotreatment were compared. LV-EIMS (12 eV) analysis of Wilsonville CDL'S before and after hydrotreatment produces very similar spectral patterns as obtained by FIMS. This is especially true for the more highly aromatic hydrotreater feed samples since the hydroaromatic compounds that dominate the hydrotreater product sampler tend to fragment more under LV-MS conditions. Canonical variate analysis confirms that the mass spectral patterns produced by both techniques are highly correlated with the exception of the higher mass range (above m/z 300) that is severely under-represented in the LV-EIMS patterns, due to lower inlet temperatures and to mass discrimination effects in quadrupole MS systems. Furthermore, in spite of the highly complex nature of the original spectral profiles, use of multivariate statistical analysis techniques, such as factor analysis and canonical correlation analysis, enables "numerical extraction" of simplified spectral patterns which can be tentatively interpreted in terms of chemical components or compound series.
1989
Investigation of the Molecular Structure of Organic Sulfur in Coal by XAFS Spectroscopy
Huffman, G.P.; Huggins, F.E.; Mitra, S.; Shah, N.; Pugmire, R.J.; Davis, B.H.; Lytle, F.W. and Greegor, R.B.
Energy & Fuels, 3, 200, 1989. Funded by US Department of Energy.
X-ray absorption fine structure (XAFS) spectroscopy has been used to investigate the molecular structure of organic sulfur in a suite of maceral separates and in several biodesulfurized and extracted coal specimens. For most samples, the X-ray absorption near-edge structure (XANES) exhibits sharp peaks just above the absorption edge that are characteristic of s Æ p transitions of compounds containing an aromatically bound sulfur atom and a broad, structured maximum at somewhat higher energies. The latter maximum is believed to arise from resonant backscattering of photoelectrons by carbon atoms 3.5-4.1 Å from the sulfur atom and possibly from s Æ p transitions of sulfur bonded to oxygen. The radial structure functions derived by Fourier analysis of the EXAFS exhibit peaks at distances that are compatible with the first three neighbor shells surrounding an aromatically bound sulfur atom.
1988-1987
Off-Line Process Monitoring of Coal-Derived Liquid Fuels by Computer Assisted Low Mass Spectrometry
Taghizadeh, K.; Davis, B.H.; Windig, W. and Meuzelaar, H.L.C.
Fossil Fuel Analysis by Mass Spectrometry, 1988, T.A. Milne, (ed.), in press. Funded by Commonwealth of Kentucky, Kentucky Energy Cabinet, US Department of Energy and Consortium For Fossil Fuel Liquefaction Science.
Compositional changes of Coal-Derived Liquids (CDL's) during hydrotreatment on fixed bed catalysts can be investigated by Low Voltage (12 eV) MS in combination with multivariate analysis without chromatographic preseparation. Low voltage (12 eV) MS data were obtained and compared under two inlet conditions; MS inlet (1) at ambient temperatures and (2) preheated to about 200ºC. The major trend found in both data sets by Factor analysis was the hydrotreatment effect, namely hydroaromatic (hydrotreater product) vs. aromatic (hydrotreater feed) compounds. A second "time + temperature" trend which reflected the aging of the catalyst as well as the temperature of the hydrotreater reactor was only obtained under ambient inlet temperature conditions. Numerically extracted spectra along the second trend show that more low molecular weight components were found early in the process and also at lower temperatures, whereas more of the higher molecular weight components, primarily alkyl substituted polynuclear aromatics, were obtained later in the process at higher temperatures of the hydrotreater.
A supercritical fluid chromatographic system was constructed to provide separations and fraction collection on a semipreparative scale. Columns packed with silica materials of intermediate particle sizes (30-70 mm) were used to allow dynamic pressure programming with minimum pressure drop of the CO2 mobile phase along the length of the column. A variety of complex coal- and petroleum-derived polycyclic aromatic compound mixtures were fractionated according to the number of aromatic rings using columns packed with an NH2- modified stationary phase bonded on silica particles. The CO2 mobile phase was programmed with an alternating series of linear pressure ramps and isobaric intervals to effect even peak spacing and near base line resolution of compounds of differing ring number in a coal tar. A solvent refined coal heavy distillate and a crude oil were similarly fractionated. Effluents were monitored with an ultraviolet spectrophotometer at 254 nm and a flame ionization detector while fractions were collected in pressurized vessels for subsequent analysis by capillary gas chromatography. Sample capacities of up to 20 mg were possible with this system.
Investigation of the Atomic and Physical Structure of Organic and Inorganic Sulfur in Coal
Huffman, G.P.; Huggins, F.E.; Shah, N.; Bhattacharyya, D.; Pugmire, R.J.; Davis, B.H.; Lytle, F.W. and Greegor, R.B.
Processing and Utilization of High Sulfur Coals II, 3-12, 1987. 10 pgs. Funded by US Department of Energy.
A complete description of the microstructure and molecular state of sulfur in coal can be achieved by combining several experimental techniques. For quantitative analysis of pyrite and its transformation products resulting from oxidative or reductive processes, Fe Mossbauer spectroscopy appears to be the best technique available. Computer-controlled scanning electron microscopy (CCSEM) provides an excellent method of measuring the particle size distributions of pyrite and its transformation products, information that is critical in physical and biological cleaning processes. Finally, it is shown that X-ray absorption fine structure spectroscopy, usually referred to as EXAFS spectroscopy, is capable of determining the atomic structure of organic or other forms of sulfur in coal and coal derivatives. EXAFS data will be presented on organic sulfur in standard compounds, maceral separates, and microbially desulfurized coal.
Comparison of Low Voltage and Field Ionization Mass Spectra of Coal Derived Liquids from the Wilsonville Plant
Taghizadeh, K.; Hardy, R.H.; Davis, B.H. and Meuzelaar, H.L.C.
Submitted to Analytical Chemistry, 1988. Funded by Commonwealth of Kentucky, Kentucky Energy Cabinet, and US Department of Energy.
Low voltage (LV) and field ionization (FI) mass spectral of coal-derived liquids (CDL) before and after hydrotreatment from the Wilsonville Coal liquefaction pilot plant were compared. LV-MS (12eV) analysis of Wilsonville CDL'S before and after hydrotreatment produces very similar spectral patterns as obtained by FI-MS. This is especially true for the more highly aromatic hydrotreater feed samples since hydroaromatic compounds tend to fragment more under LV-MS conditions. Canonical variate analysis confirms that the mass spectral patterns produced by both techniques are highly correlated with the exception of the higher mass range (above m/z 300) that appears to be underrepresented in the LV-MS patterns, primarily as a result of lower inlet temperatures. Furthermore, in spite of the highly complex nature of the original spectral profiles, use of multivariate statistical analysis techniques, such as factor analysis and canonical correlation analysis, enables "numerical extraction" of simplified spectral patterns which can be tentatively interpreted in terms of chemical components or compound series.
Hydrotreatment Effects on Wilsonville Coal Liquids; Computer-Assisted Evaluation of Multisource Analytical Data
Taghizadeh, K.; Davis, B.H. and Meuzelaar, H.L.C.
ACS Preprint, 32, 4, 1987, New Orleans. Funded by Commonwealth of Kentucky, Kentucky, Energy Cabinet, US Department of Energy and Consortium For Fossil Fuel Liquefaction Science.
Due to the high complexity of coal-derived liquids no single analytical method provides adequate compositional information. In this study, low voltage MS data on Wilsonville coal liquid samples from a single 67-day run in the ITSL mode using Illinois #6 coal were combined with available H and C-13 NMR data, as well as conventional characterization data, by means of computerized multivariate analysis techniques, viz. canonical correlation analysis. The low voltage MS data revealed a high degree of correlation with the NMR data as well as the conventional data. As expected, the hydrotreatment step is characterized by an increase in the relative abundance of hydroaromatic compounds accompanied by a decreased abundance of condensed aromatic hydrocarbons, as well as a strong reduction in heteroatomic compounds. Moreover, the combined effect of catalyst aging and reactor temperature is a decrease in the relative abundance of lower molecular weight-compounds and more reactive chemical structures (e.g., alkyltetralins). Furthermore, during the later stages of the run nitrogen- and sulfur-containing moieties appear to be less efficiently removed in the hydrotreatment step.
EXAFS Investigation of Organic Sulfur in Coal
Huffman, G.P.; Huggins, F.E.; Shah, N.; Bhattacharyya, D.; Pugmire, R.J.; Davis, B.H.; Lytle, F.W. and Greegor, R.B.
ACS Div. of Fuel Chemistry, 33, (1), 200-208, 1988. 9 pgs. Funded by US Department of Energy.
EXAFS spectroscopy is shown to be a very promising technique for investigating the molecular structure of organically bound sulfur in coal and coal derivatives. The current paper presents sulfur K-shell EXAFS results for a number of a maceral separates prepared by density gradient centrifugation and for several biodesulfurized coals. Both the near-edge structure and the radial structure functions exhibit some similarities to dibenzothiophene. However, a broad peak occurs in the XANES region of the coal spectra that is not observed for the molecular structures usually ascribed to organic sulfur in coal. This is believed to arise from resonant photoelectron scattering from second and third nearest neighbor carbon shells and from sulfur bonded to oxygen.