Weathering effects on structure and reactivity of US coals: Third quarterly report

Technical Report · Thu Jan 01 04:00:00 EST 1987

OSTI ID:6054042

Meuzelaar, H L.C.; Hill, G R; Yun, Yongseung; Jakab, E

The temperature of maximum rate of weight loss in thermal gravimetric analysis occurs at 520/sup 0/C for Upper Freeport coal (mvb) and at 470/sup 0/C for Anderson coal (subbituminous C). The maximum rate of weight loss decreases significantly with the degree of weathering. This trend appears to be due to two separate weathering effects: (1) a decreased total volatile matter yield, consequently an increased char yield, and (2) a broader distribution of activation energy in weathered coal. Evolution profiles on each mass with temperature show the dramatic effect of weathering, confirming that kinetics in devolatilization and pyrolysis between fresh and weathered coals are quite different. Especially, evolution profile of carbon dioxide (m/z 44) shows the significant formation of carboxylic functional groups as weathering proceeds. TG/MS analysis shows that both aromatic and aliphatic moieties in coal decreases with the degree of weathering. This trend was more profound in Upper Freeport coal (mbv) than Anderson coal (subbituminous). The TG/MS technique is a valuable tool for investigating the kinetics of coal pyrolysis and combustion. More elaborate TG/MS studies are needed to examine the effect of weathering on kinetics and, thus, to determine the effect on variables in the real processes, such as combustion, liquefaction and gasification. This kind of study will give the sufficient information for the prevention of energy loss during coal usage from weathering. 13 refs., 9 figs., 1 tab.

• Research Organization: Utah Univ., Salt Lake City (USA)
• DOE Contract Number: FG22-84PC70798
• OSTI ID: 6054042
• Report Number(s): DOE/PC/70798-T10; ON: DE87013763
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010600* -- Coal
Lignite
& Peat-- Properties & Composition
CARBON 13
CARBON ISOTOPES
CARBONACEOUS MATERIALS
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COAL
DECOMPOSITION
ENERGY SOURCES
EVEN-ODD NUCLEI
FOSSIL FUELS
FUELS
GRAVIMETRIC ANALYSIS
INFRARED SPECTRA
IRON COMPOUNDS
IRON SULFIDES
ISOTOPES
KINETICS
LIGHT NUCLEI
MAGNETIC RESONANCE
MASS SPECTROSCOPY
MATERIALS
MINERALS
MOESSBAUER EFFECT
MOLECULAR STRUCTURE
NUCLEAR MAGNETIC RESONANCE
NUCLEI
PYRITE
PYROLYSIS
QUANTITATIVE CHEMICAL ANALYSIS
REACTION KINETICS
RESONANCE
SPECTRA
SPECTROSCOPY
STABLE ISOTOPES
SULFIDE MINERALS
SULFIDES
SULFUR COMPOUNDS
THERMAL ANALYSIS
THERMAL GRAVIMETRIC ANALYSIS
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENT COMPOUNDS
WEATHERING