Calculation of calorific values of coals from ultimate analyses: theoretical basis and geochemical implications. Final report. Part 8
The various formulae for calculating calorific values for coals from ultimate analyses depend essentially on a propositon due to Dulong, that the heat of combustion of an organic compound is nearly equal to the heats of combustion of the elements in it, multiplied by their percentage content in the compound in question. This proposition assumes that the enthalpy of decomposition is negligible compared with the heat of combustion. The various published formulae, such as that due to Mott and Spooner, include empirical adjustments to allow for the fact that the enthalpy of formation or decomposition of no organic compound is zero (except rarely by chance). A new equation is proposed, which excludes empirical correction terms but includes a term explicitly related to the enthalpy of decomposition. As expected from the behavior of known compounds, this enthalpy varies with rank, but it also varies at the same level of rank with the geological history of the sample: rank is not the only source of variance in coal properties. The new equation is at least as effective in predicting calorific values for a set of 992 coals as equivalent equations derived for 6 subsets of the coals. On the whole, the distributions of differences between observed and calculated calorific values are skewed to only a small extent. About 86% of the differences lie between -300 and +300 Btu/lb (+- 700 kJ/kg). 10 references, 7 figures, 4 tables.
- Research Organization:
- Pennsylvania State Univ., University Park, PA (United States)
- DOE Contract Number:
- AC22-80PC30013
- OSTI ID:
- 5229172
- Report Number(s):
- DOE/PC/30013-T5; ON: DE84007965
- 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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CALORIFIC VALUE
CALCULATION METHODS
COAL
CHEMICAL ANALYSIS
COAL RANK
COMBUSTION HEAT
ENTHALPY
EQUATIONS
CARBONACEOUS MATERIALS
COMBUSTION PROPERTIES
ENERGY
ENERGY SOURCES
FOSSIL FUELS
FUELS
HEAT
MATERIALS
PHYSICAL PROPERTIES
REACTION HEAT
THERMODYNAMIC PROPERTIES
010600* - Coal
Lignite
& Peat- Properties & Composition