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

Technical Report · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5254759

Meuzelaar, H L.C.; Hill, G R; Windig, W; Jakab, E

Highlights of the third quarter: (1) Upper Freeport Seam coal loses only 0.48% of its calorific value, but the volatile matter/fixed carbon ratio decreased from 0.48 to 0.38 during weathering at 100/sup 0/C for 10 days. Since the measurement of oxygen consumption indicates only low reaction rates, the drastic changes in VM/FC ratio are probably due to the loss of ''mobile phase'' molecules by ''grafting'' reactions with the ''network phase''. (2) The fresh coal has a high Free Swelling Index value (8.5) that is not sensitive for weathering during the first three days but drops to 1.5 within ten days of weathering at 100/sup 0/C. (3) Conclusions cannot be drawn about the rate of oxygen uptake on the basis of weight determinations alone because the rate of gases evolved (e.g., CO + CO/sub 2/ + H/sub 2/O) is comparable to the amount of oxygen consumed. (4) The reactions are faster at the beginning of the weathering process as established by oxygen consumption measurements. Carbon dioxide production curves as well as the weight change curve show similar tendencies. (5) Comparison of the Upper Freeport seam coal with other US coals reveals that the higher the rank the smaller the reactivity towards oxygen on the basis of oxygen uptake and calorific value loss. (6) Discriminant analysis of pyrolysis mass spectra shows decreased intensities of alkyl naphthalene and alkyl phenol series as well as sulfur compounds in the pyrolyzates of weathered samples. Besides small polar molecules (e.g., CO, CO/sub 2/, acids), aliphatic hydrocarbon and/or fatty acid signals become more intensive in the spectra of weathered coals. (7) Time-resolved Py-MS analysis of fresh and weathered coal indicates marked changes at lower decomposition temperatures (decrease of alkyl naphthalenes and increased evolution of carbon dioxide, acids). 12 refs., 10 figs., 2 tabs.

• Research Organization: Utah Univ., Salt Lake City (USA). Biomaterials Profiling Center
• DOE Contract Number: FG22-84PC70798
• OSTI ID: 5254759
• Report Number(s): DOE/PC/70798-T3; ON: DE85017240
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010600* -- Coal
Lignite
& Peat-- Properties & Composition
013000 -- Coal
Lignite
& Peat-- Transport
Handling
& Storage
AROMATICS
CALORIFIC VALUE
CARBONACEOUS MATERIALS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHROMATOGRAPHY
COAL
COAL RANK
COMBUSTION PROPERTIES
CONDENSED AROMATICS
CONSUMPTION RATES
DATA
DECOMPOSITION
ELEMENTS
ENERGY LOSSES
ENERGY SOURCES
EXPERIMENTAL DATA
FOSSIL FUELS
FUELS
GAS CHROMATOGRAPHY
HYDROCARBONS
HYDROXY COMPOUNDS
INFORMATION
KINETICS
LOSSES
MASS SPECTROSCOPY
MATERIALS
MATTER
NAPHTHALENE
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
OXYGEN
PHENOL
PHENOLS
PYROLYSIS
REACTION KINETICS
SEPARATION PROCESSES
SPECTROSCOPY
SWELLING
THERMOCHEMICAL PROCESSES
VOLATILE MATTER
WEATHERING