Finding order in coal pyrolysis kinetics
A number of experiments have suggested that the rate constants for the release of tar and for the thermal decomposition of the various functional groups in coal pyrolysis depend on the nature of the bridging bond or of the functional group, but appears relatively insensitive to coal rank for lignites, subbituminous and bituminous coals. The principal variation of pyrolysis behavior with rank is due to variations in the concentrations of functional groups and hence, the amount of each pyrolysis product. If the insensitivity of coal pyrolysis kinetics to coal rank can be generally demonstrated, it represents an important simplifying assumption in any general theory of coal pyrolysis. But the rank insensitivity of rate constants is controversial. There are two major questions. What species exhibit rank insensitive kinetics. Quantitatively, what does insensitivity mean, variations less than factors of two, ten, hundred, etc. This paper considers whether pyrolysis data in the literature support the hypothesis of rank insensitive kinetic rate constants. The experiments considered vary duration from 1.4 millisecond to 12 hours and in temperature from 350/sup 0/C to 1800/sup 0/C. Considering the available data, it appears that the decomposition of aliphatic and methyl functional groups, the loss of aromatic hydrogen and the evolution of tar and hydrocarbon species have rates which are relatively insensitive to rank variation. The rate varies by at most a factor of 5 between lignite and bituminous coals. Oxygen species are somewhat more rank sensitive. The factor of 5 variation in rate due to coal rank is substantially less than the factors of 100 to 10,000 in varition typical of reported rates. 56 references, 49 figures, 4 table.
- Research Organization:
- Advanced Fuel Research, Inc., East Hartford, CT (USA)
- DOE Contract Number:
- AC21-81FE05122
- OSTI ID:
- 5524981
- Report Number(s):
- DOE/FE/05122-1485; ON: DE84000225
- Resource Relation:
- Other Information: Portions are illegible in microfiche products. Original copy available until stock is exhausted
- Country of Publication:
- United States
- Language:
- English
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BITUMINOUS COAL
PYROLYSIS
CARBON DIOXIDE
CHEMICAL REACTION YIELD
CARBON MONOXIDE
CHARS
CHEMICAL COMPOSITION
INFRARED SPECTRA
COAL RANK
CORRELATIONS
COAL TAR
ETHYLENE
HYDROGEN
LIGNITE
METHANE
SUBBITUMINOUS COAL
CHEMICAL BONDS
CHEMICAL REACTION KINETICS
DATA COMPILATION
FOURIER TRANSFORMATION
HEAT TRANSFER
MASS TRANSFER
ALKANES
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BLACK COAL
BROWN COAL
CARBON COMPOUNDS
CARBON OXIDES
CARBONACEOUS MATERIALS
CHALCOGENIDES
CHEMICAL REACTIONS
COAL
DATA
DECOMPOSITION
ELEMENTS
ENERGY SOURCES
ENERGY TRANSFER
FOSSIL FUELS
FUELS
HYDROCARBONS
INFORMATION
INTEGRAL TRANSFORMATIONS
KINETICS
MATERIALS
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
OTHER ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PYROLYSIS PRODUCTS
REACTION KINETICS
SPECTRA
TAR
THERMOCHEMICAL PROCESSES
TRANSFORMATIONS
YIELDS
010406* - Coal & Coal Products- Pyrolysis & Cracking- (-1987)