Li, W
1996
Determination of Volatile Hydrocarbons in Coals and Shales Using Supercritical Fluid Extraction and Chromatography
Li, W.; Lazar, I.M.; Wan, Y.J.; Butala, S.; Shen, Y.; Malik, A. and Lee, M.L
Energy & Fuels, 1996 (in press). Funded by ACERC and Gas Research Institute.
Conventional analytical techniques, such as headspace gas chromatography and Soxhlet extraction, can provide compositional information for the gaseous (C1-5) and heavy (C15+) hydrocarbon constituents, respectively. The volatile (C6-14) hydrocarbons, if present, usually go undetected because of volatility fractionation and loss. In this study supercritical CO2 was used to extract the C6-C14 volatile hydrocarbons from pulverized coal samples. Capillary column gas chromatography/mass spectrometry was used to identify the mixture components, and packed capillary column supercritical fluid chromatography was used to separate and quantify the aliphatic and aromatic hydrocarbon class fractions. It was found that the compositions of the light hydrocarbon fractions included several homologous series of normal and branched aliphatic hydrocarbons, cyclic and aromatic hydrocarbons, and alkyl-substituted benzenes and naphthalenes; the concentrations of these volatile hydrocarbons ranged between 0.01 to 0.2% (by weight) of the bulk material for the different coal and shale samples.
Analysis of Coal Structure Via Successive Catalytic Depolymerization and Supercritical Fluid/Enhanced Liquid Extraction
Wan, Y.J.; Butala, S.; Li, W. and Lee, M.L.
Proceedings of the Pittcon '96 (Pittsburgh Conference), Chicago, Illinois, March 6, 1996. Funded by ACERC.
To understand the original chemical features of the intact coal structure, a new method has been developed for depolymerization and extraction of coal. It involves successive catalyzed depolymerization reactions under mild and organic solvent free conditions, each immediately followed in in-situ supercritical fluid (carbon dioxide) extraction and enhanced solvent (methylene chloride) extraction of the reaction matrix. The procedure is simple and the system is easy to operate. The timely removal of coal products avoids any retrograde reactions that complicate the products. Compared with coal head distillation, supercritical fluid extraction and enhanced liquid extraction is fast and can be used to analyze a very small amount of coal for analytical purposes. Experimental detail, extraction yields, and GC and GC/MS characterization of the products associated with coal structure will be presented. From the comparison of the composition of products from different depolymerization steps, it appears that coal has a common macromolecular skeletal structure, despite the well-established heterogeneity of coal.
Li, W
1996
Determination of Volatile Hydrocarbons in Coals and Shales Using Supercritical Fluid Extraction and Chromatography
Li, W.; Lazar, I.M.; Wan, Y.J.; Butala, S.; Shen, Y.; Malik, A. and Lee, M.L
Energy & Fuels, 1996 (in press). Funded by ACERC and Gas Research Institute.
Conventional analytical techniques, such as headspace gas chromatography and Soxhlet extraction, can provide compositional information for the gaseous (C1-5) and heavy (C15+) hydrocarbon constituents, respectively. The volatile (C6-14) hydrocarbons, if present, usually go undetected because of volatility fractionation and loss. In this study supercritical CO2 was used to extract the C6-C14 volatile hydrocarbons from pulverized coal samples. Capillary column gas chromatography/mass spectrometry was used to identify the mixture components, and packed capillary column supercritical fluid chromatography was used to separate and quantify the aliphatic and aromatic hydrocarbon class fractions. It was found that the compositions of the light hydrocarbon fractions included several homologous series of normal and branched aliphatic hydrocarbons, cyclic and aromatic hydrocarbons, and alkyl-substituted benzenes and naphthalenes; the concentrations of these volatile hydrocarbons ranged between 0.01 to 0.2% (by weight) of the bulk material for the different coal and shale samples.
Analysis of Coal Structure Via Successive Catalytic Depolymerization and Supercritical Fluid/Enhanced Liquid Extraction
Wan, Y.J.; Butala, S.; Li, W. and Lee, M.L.
Proceedings of the Pittcon '96 (Pittsburgh Conference), Chicago, Illinois, March 6, 1996. Funded by ACERC.
To understand the original chemical features of the intact coal structure, a new method has been developed for depolymerization and extraction of coal. It involves successive catalyzed depolymerization reactions under mild and organic solvent free conditions, each immediately followed in in-situ supercritical fluid (carbon dioxide) extraction and enhanced solvent (methylene chloride) extraction of the reaction matrix. The procedure is simple and the system is easy to operate. The timely removal of coal products avoids any retrograde reactions that complicate the products. Compared with coal head distillation, supercritical fluid extraction and enhanced liquid extraction is fast and can be used to analyze a very small amount of coal for analytical purposes. Experimental detail, extraction yields, and GC and GC/MS characterization of the products associated with coal structure will be presented. From the comparison of the composition of products from different depolymerization steps, it appears that coal has a common macromolecular skeletal structure, despite the well-established heterogeneity of coal.