Pyrolysis of bituminous coal blocks
Internal heat and mass transfer resistances were observed to affect the pyrolysis of bituminous coal blocks in experiments at Oak Ridge National Laboratory (ORNL). Pyrolysis, the reaction step which occurs after drying and before gasification, is conventionally studied by the rapid heating of powdered samples so that internal resistances can be minimized. Because monolithic coal rather than powdered coal is reacted in underground coal gasification (UCG), the measurement of differences between powder and block pyrolysis is particularly important to the successful, broadly applicable modeling and development of UCG. In a block pyrolysis reactor at ORNL, 0.15-m (6-in.)-diam cylinders of bituminous coal were heated at 0.3, 3, or 14/sup 0/C/min; in inert gas (Ar) and in H/sub 2/; and to maximum pyrolysis temperatures of 600 to 1000/sup 0/C. In the tests performed at higher heating rates, a significant reduction in swelling of the coal was observed which can be correlated with the steep temperature gradients caused by heat transfer resistances. Also, at higher heating rates, pyrolysis gas evolution was increased as oil and char yields decreased. Such behavior is evidence of secondary cracking reactions caused by a combination of the steep temperature gradients and mass transfer resistances.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- Sponsoring Organization:
- USDOE Office of Fossil Energy (FE)
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 6681607
- Report Number(s):
- CONF-780723-6
- Country of Publication:
- United States
- Language:
- English
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ARGON
ATMOSPHERES
BITUMINOUS COAL
BLACK COAL
CARBONACEOUS MATERIALS
CHARS
CHEMICAL REACTIONS
COAL
COAL GASIFICATION
COAL LIQUIDS
CONTROLLED ATMOSPHERES
CRACKING
CRYOGENIC FLUIDS
DECOMPOSITION
ELEMENTS
ENERGY SOURCES
ENERGY TRANSFER
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS FUELS
GASES
GASIFICATION
HEAT TRANSFER
HEATING RATE
HYDROGEN
IN-SITU GASIFICATION
IN-SITU PROCESSING
MASS TRANSFER
NONMETALS
PROCESSING
PYROLYSIS
RARE GASES
SWELLING
TEMPERATURE GRADIENTS
THERMAL CRACKING
THERMOCHEMICAL PROCESSES
YIELDS