Macromolecular structure of low rank coals and lignites

Thesis/Dissertation · Wed Jan 01 00:00:00 EST 1986

OSTI ID:5062321

Shawver, S E

The low rank coals, lignites and subbituminous coals, are considered to be three dimensionally covalently crosslinked macromolecules. The solvent swelling methodology used to characterize the macromolecular structure of bituminous coals is extended to the lower-rank coals. The pyridine-extracted subbituminous coal obeyed the predictions of regular solution theory, while the pyridine-extracted lignites did not. The non-polar solubility parameter of the pyridine-extracted subbituminous coal was estimated to be 9.5 (cal/cm/sup 3/)/sup 1/2/. The O-acetylated and O-methylated subbituminous coals were assigned solubility parameters of 9.2 (cal/cm/sup 3/)/sup 1/2/. Solubility parameters of 9.2 and 9.1 (cal/cm/sup 3/)/sup 1/2/ were assigned to the two O-acetylated lignite samples. Flory Interaction Parameters were calculated for a series of non-polar solvent-coal pairs. The Flory-Rehner and Kovac Equations were applied to the solvent swelling data to estimate crosslink densities and the number average molecular weight between crosslinks of the O-acetylated lignites and pyridine-extracted subbituminous coal. The low rank coals contain hydrogen bonds which serve as crosslinks in the coal network. Solvent swelling experiments with non-polar solvents indicated the removal of ionic bonds was found to have little effect on the macromolecular structure of the lower rank coals.

• Research Organization: Tennessee Univ., Knoxville (USA)
• OSTI ID: 5062321
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
LIGNITE
MOLECULAR STRUCTURE
SUBBITUMINOUS COAL
CHEMICAL BONDS
CROSS-LINKING
SOLUBILITY
SOLVENTS
SWELLING
BROWN COAL
CARBONACEOUS MATERIALS
CHEMICAL REACTIONS
COAL
ENERGY SOURCES
FOSSIL FUELS
FUELS
MATERIALS
POLYMERIZATION
010600* - Coal
Lignite
& Peat- Properties & Composition