Lo, R
1992
Spectroscopic Studies of Coal Maceral Depolymerization Effected by an Iron-Based Catalyst
Wang, H.P.; Lo, R.; Sommerfeld, D.A.; Huai, H.; Pugmire, R.J.; Shabtai, J.S. and Eyring, E.M.
Fuel, 71(7):723-729, 1992. Funded by US Department of Energy.
Demineralized Hiawatha (Utah) coal was divided into narrow density fractions of resinite and vitrinite macerals using a density gradient centrifugation technique. The distribution of an iron-based catalyst in the coal maceral matrix was studied using an electron probe microanalyser. The data indicate that the iron catalyst is evenly dispersed inside the vitrinite. This uniform dispersion is preserved upon mild (275ºC) hydrotreatment and attendant partial depolymerization of the vitrinite maceral. However, the iron catalyst does not completely penetrate into the resinite maceral matrix due to a lack of microporosity. The small amount of dispersed iron catalyst in the resinite causes some depolymerization of maceral components, e.g. dimers, trimers, or higher polymers, into monomers. Due to the insufficient dispersion of the iron catalyst in the resinite a competing thermal breakdown of the maceral occurs. This apparently involved a partial dehydrogenation reaction that may be favored during the hydrotreatment of resinite.
1991
Chemical Composition and Origin of Fossil Resins from Utah Wasatch Plateau Coal
Meuzelaar, H.L.C.; Huai, H.; Lo, R. and Dworzanski, J.P.
Fuel Processing Technology, 28:119-134, 1991. Funded by Pittsburgh Energy Technology Center/Consortium for Fossil Fuel Liquefaction, ACERC and Advanced Coal Technology Center.
In order to arrive at a more detailed chemical description of fossil coal associated resins we need to distinguish between micropetrographic, organic geochemical and process technological definitions, each of which may encompass varying quantities of constituents unrelated to fossil tree resins. New information on composition and origin of Utah Wasatch Plateau coal resins obtained by Curie-point pyrolysis/evaporation in combination with iso-butane chemical ionization mass spectrometry, as presented in this paper, points to the presence of four more or less distinct resin components: (1) a sesquiterpenoid polymer; (2) sesqui- and triterpenoid monomers and dimers; (3) a suite of triterpenoid alcohols, ketones and acids; and (4) a series of increasingly aromatized hydrocarbons with naphthalene and picene type skeletons. Moreover, a strong similarity is found between the composition of recent dammar resin and fossil. Wasatch Plateau coal resins indicating a possible Angiosperm (fam. Dipterocarpaceae) origin of these Upper Cretaceous coal resins. Some of the technological implications of these findings and the consequent need for a more precise chemical definition and nomenclature are discussed.
1990
Mass Spectrometric Studies of the Chemical Composition of Coal Tars Produced in a Laminar Flow Reactor
Lo, R.; Pugmire, R.J.; Fletcher, T.H. and Meuzelaar, H.L.C.
Preprints for Papers Presented at the 200th ACS National Meeting, 35 (3), 697-704, Washington, D.C., 1990. Funded by ACERC and Consortium for Fossil Fuel Liquifaction Science.
Curie-point desorption in combination with Gas Chromatography/Mass Spectrometry (GC/MS) and, alternatively, with direct Low Voltage Mass Spectrometry (LV-MS) was used to investigate the chemical composition and structure of condensed tar vapors produced during rapid devolatilization (heating rate ~10,000 K/sec) of carefully sized coal particles representing the Beulah Zap, Big Blue, Illinois #6, Pittsburgh #8, and Pocahontas #3 seams, respectively, using the laminar flow reactor described by Fletcher et al at two gas temperatures (1050 K and 1250).
Tar samples were collected by means of a special probe at different points downstream of and corresponding to residence times between 70 and 250 ms. GC/MS analyses of the corresponding tars indicate that the degree of aromaticity increased rapidly as a function of residence time at the 1250 K gas temperature condition. Moreover, at 1250 K devolatilization is complete within 70 ms and beginning secondary gas phase reactions of tar vapors (viz. marked increases in PNAH content and corresponding decreases in phenolic components) are observed within less than 100 ms. However, at 1050 K the coal devolatilization process appears to be barely complete after 250 ms and little or no evidence of secondary gas phase reactions is found.
A Comparative Study of Eight U.S. Coals by Several Different Pyrolysis Mass Spectrometry Techniques
Huai, H.; Lo, R.; Yun, Y. and Meuzelaar, H.L.C.
ACS Division of Chemistry, 35 (3), Washington, D.C., 1990. (Also Proc. of the 38th ASMS Conference on Mass Spectrometry and Allied Topics, Tucson, AZ, 601-602, 1990). Funded by Consortium for Fossil Fuel Liquefaction Science.
Eight U.S. coals of different rank and/or composition, obtained through the Argonne National Laboratory Premium Coal Sample Program, were analyzed by means of several different pyrolysis-MS (Py-MS) techniques, namely: direct Curie-Point Py-MS, Curie-point Py-GC/MS (including GC/EIMS, GC/CIMS and "short column" GC/CIMS), and vacuum thermogravimetry/MS (TG/MS). The data obtained were compared to Pyrolysis-Field Ionization MS (Py-FIMS) data.
The results show a very good agreement between all techniques used in spite of the marked differences in pyrolysis techniques (Curie-point, furnace, direct probe), "soft" ionization methods (low voltage EI, CI FI) and mass spectrometer types (quadrupole, ion trap, magnetic sector) used. As might be expected, the most pronounced variations between techniques appear to be due to mass dependent differences in ion transmissivity and detector response, with the type of soft ionization method taking second place and the type of pyrolysis technique showing least effect on the results. Whereas Py-FIMS provides the most complete and detailed overview of the coal pyrolysis tars, Cuire-point Py-MS and TG/MS methods provide more reliable information on relatively light gaseous products, and Curie-point Py-GC/MS shows the detail composition of the 2/3 of the total pyrolysis tars.
Lo, R
1992
Spectroscopic Studies of Coal Maceral Depolymerization Effected by an Iron-Based Catalyst
Wang, H.P.; Lo, R.; Sommerfeld, D.A.; Huai, H.; Pugmire, R.J.; Shabtai, J.S. and Eyring, E.M.
Fuel, 71(7):723-729, 1992. Funded by US Department of Energy.
Demineralized Hiawatha (Utah) coal was divided into narrow density fractions of resinite and vitrinite macerals using a density gradient centrifugation technique. The distribution of an iron-based catalyst in the coal maceral matrix was studied using an electron probe microanalyser. The data indicate that the iron catalyst is evenly dispersed inside the vitrinite. This uniform dispersion is preserved upon mild (275ºC) hydrotreatment and attendant partial depolymerization of the vitrinite maceral. However, the iron catalyst does not completely penetrate into the resinite maceral matrix due to a lack of microporosity. The small amount of dispersed iron catalyst in the resinite causes some depolymerization of maceral components, e.g. dimers, trimers, or higher polymers, into monomers. Due to the insufficient dispersion of the iron catalyst in the resinite a competing thermal breakdown of the maceral occurs. This apparently involved a partial dehydrogenation reaction that may be favored during the hydrotreatment of resinite.
1991
Chemical Composition and Origin of Fossil Resins from Utah Wasatch Plateau Coal
Meuzelaar, H.L.C.; Huai, H.; Lo, R. and Dworzanski, J.P.
Fuel Processing Technology, 28:119-134, 1991. Funded by Pittsburgh Energy Technology Center/Consortium for Fossil Fuel Liquefaction, ACERC and Advanced Coal Technology Center.
In order to arrive at a more detailed chemical description of fossil coal associated resins we need to distinguish between micropetrographic, organic geochemical and process technological definitions, each of which may encompass varying quantities of constituents unrelated to fossil tree resins. New information on composition and origin of Utah Wasatch Plateau coal resins obtained by Curie-point pyrolysis/evaporation in combination with iso-butane chemical ionization mass spectrometry, as presented in this paper, points to the presence of four more or less distinct resin components: (1) a sesquiterpenoid polymer; (2) sesqui- and triterpenoid monomers and dimers; (3) a suite of triterpenoid alcohols, ketones and acids; and (4) a series of increasingly aromatized hydrocarbons with naphthalene and picene type skeletons. Moreover, a strong similarity is found between the composition of recent dammar resin and fossil. Wasatch Plateau coal resins indicating a possible Angiosperm (fam. Dipterocarpaceae) origin of these Upper Cretaceous coal resins. Some of the technological implications of these findings and the consequent need for a more precise chemical definition and nomenclature are discussed.
1990
Mass Spectrometric Studies of the Chemical Composition of Coal Tars Produced in a Laminar Flow Reactor
Lo, R.; Pugmire, R.J.; Fletcher, T.H. and Meuzelaar, H.L.C.
Preprints for Papers Presented at the 200th ACS National Meeting, 35 (3), 697-704, Washington, D.C., 1990. Funded by ACERC and Consortium for Fossil Fuel Liquifaction Science.
Curie-point desorption in combination with Gas Chromatography/Mass Spectrometry (GC/MS) and, alternatively, with direct Low Voltage Mass Spectrometry (LV-MS) was used to investigate the chemical composition and structure of condensed tar vapors produced during rapid devolatilization (heating rate ~10,000 K/sec) of carefully sized coal particles representing the Beulah Zap, Big Blue, Illinois #6, Pittsburgh #8, and Pocahontas #3 seams, respectively, using the laminar flow reactor described by Fletcher et al at two gas temperatures (1050 K and 1250).
Tar samples were collected by means of a special probe at different points downstream of and corresponding to residence times between 70 and 250 ms. GC/MS analyses of the corresponding tars indicate that the degree of aromaticity increased rapidly as a function of residence time at the 1250 K gas temperature condition. Moreover, at 1250 K devolatilization is complete within 70 ms and beginning secondary gas phase reactions of tar vapors (viz. marked increases in PNAH content and corresponding decreases in phenolic components) are observed within less than 100 ms. However, at 1050 K the coal devolatilization process appears to be barely complete after 250 ms and little or no evidence of secondary gas phase reactions is found.
A Comparative Study of Eight U.S. Coals by Several Different Pyrolysis Mass Spectrometry Techniques
Huai, H.; Lo, R.; Yun, Y. and Meuzelaar, H.L.C.
ACS Division of Chemistry, 35 (3), Washington, D.C., 1990. (Also Proc. of the 38th ASMS Conference on Mass Spectrometry and Allied Topics, Tucson, AZ, 601-602, 1990). Funded by Consortium for Fossil Fuel Liquefaction Science.
Eight U.S. coals of different rank and/or composition, obtained through the Argonne National Laboratory Premium Coal Sample Program, were analyzed by means of several different pyrolysis-MS (Py-MS) techniques, namely: direct Curie-Point Py-MS, Curie-point Py-GC/MS (including GC/EIMS, GC/CIMS and "short column" GC/CIMS), and vacuum thermogravimetry/MS (TG/MS). The data obtained were compared to Pyrolysis-Field Ionization MS (Py-FIMS) data.
The results show a very good agreement between all techniques used in spite of the marked differences in pyrolysis techniques (Curie-point, furnace, direct probe), "soft" ionization methods (low voltage EI, CI FI) and mass spectrometer types (quadrupole, ion trap, magnetic sector) used. As might be expected, the most pronounced variations between techniques appear to be due to mass dependent differences in ion transmissivity and detector response, with the type of soft ionization method taking second place and the type of pyrolysis technique showing least effect on the results. Whereas Py-FIMS provides the most complete and detailed overview of the coal pyrolysis tars, Cuire-point Py-MS and TG/MS methods provide more reliable information on relatively light gaseous products, and Curie-point Py-GC/MS shows the detail composition of the 2/3 of the total pyrolysis tars.