Studies of initial reaction steps in the gasification of coal: Final report, October 1983-September 1985
This research has utilized matrix isolation FTIR and EPR for characterization of volatilized coal products. Both slow and rapid heating studies were carried out on four coals, Illinois No. 6, Pittsburgh bituminous, Rawhide sub-bituminous and Texas lignite. Pyrolysis products have been correlated to coal type and initial coal composition. Evolution of both a low and high temperature form of tar has been observed. Methylation of the hydroxyl structure in coal enhances the evolution of the low temperature form. Only the high temperature tar is found to contain free radical character. Significant temperature dependent evolution of CO, CO/sub 2/, H/sub 2/O, H/sub 2/S, CS/sub 2/, CS, HCN, C/sub 2/H/sub 4/, and CH/sub 4/ is observed and interpreted in terms of reaction mechanisms which occur during pyrolysis. Reaction of kaolinite with char is observed at high temperatures (1150 to 1500/sup 0/C) to form volatile species SiO, Al/sub 2/O, and aluminum atoms. Significant evolution of the methyl free radical was observed for the first time. This observation strongly implies that direct bond dissociation of existing methyl groups in coal is a major reaction mechanism leading to methane formation. Infrared spectra of the matrix isolated tar has shown that only the phenolic hydroxyl group remains in the tar after vaporization. Studies of methylation of the hydroxyl groups present in coal with a deuterated methyl group have allowed the identification of three distinct hydroxyl sites. They have been identified as carboxyl, phenolic and alcoholic in character. EPR spectra of the matrix isolated tars have shown significantly increased detail as compared to the respective coals. The spectra indicate that the free radical sites in the tars are delocalized over aromatic rings. Four different types of free radical species are observed and are tentatively associated with aromatic rings which contain no heterocycles as well as those with sulfur, nitrogen, and oxygen. 12 refs., 47 figs., 17 tabs.
- Research Organization:
- Rice Univ., Houston, TX (USA). Dept. of Chemistry
- DOE Contract Number:
- AC21-83MC20685
- OSTI ID:
- 6829561
- Report Number(s):
- DOE/MC/20685-2263; ON: DE87001054
- Resource Relation:
- Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CARBON DIOXIDE
CHEMICAL REACTION YIELD
CARBON MONOXIDE
CARBON SULFIDES
CHARS
CHEMICAL REACTIONS
COAL
CHEMICAL REACTION KINETICS
PYROLYSIS
COAL GASIFICATION
COAL TAR
INFRARED SPECTRA
ETHYLENE
HYDROCYANIC ACID
HYDROGEN SULFIDES
KAOLINITE
METHANE
WATER
BITUMINOUS COAL
ELECTRON SPIN RESONANCE
LIGNITE
METHYLATION
RADICALS
SUBBITUMINOUS COAL
VERY HIGH TEMPERATURE
ALKANES
ALKENES
ALUMINIUM COMPOUNDS
ALUMINIUM SILICATES
BLACK COAL
BROWN COAL
CARBON COMPOUNDS
CARBON OXIDES
CARBONACEOUS MATERIALS
CHALCOGENIDES
CYANIDES
DECOMPOSITION
ENERGY SOURCES
FOSSIL FUELS
FUELS
GASIFICATION
HYDROCARBONS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
KINETICS
MAGNETIC RESONANCE
MATERIALS
MINERALS
ORGANIC COMPOUNDS
OTHER ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PYROLYSIS PRODUCTS
REACTION KINETICS
RESONANCE
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
SPECTRA
SULFIDES
SULFUR COMPOUNDS
TAR
THERMOCHEMICAL PROCESSES
YIELDS
010404* - Coal
Lignite
& Peat- Gasification
010409 - Coal
Lignite
& Peat- Pyrolysis & Carbonization- (1987-)