Coal combustion: Effect of process conditions on char reactivity
During the past quarter, we systematically investigated the effects of particle size, pyrolysis heating rate, and heat treatment temperature on the reactivity of chars. The results show that pyrolysis heating rates or particle size do not affect the reactivity of chars in the kinetic control regime (420[degree]C). High heat treatment temperatures (HTT) slightly lowered the char intrinsic reactivities. When the char particles were reacted in the regime of diffusional limitations (625[degree]C), a significant effect of particle size was detected. We observed that decreasing final heat treatment temperatures resulted in small increases of the intrinsic reactivity for the smallest particles. For the largest particles, however, the effect of decreasing HTT was dramatic. By lowering the HTT from 775 to 625[degree]C, the reactivity of chars at 625[degree]C increased by a factor of 6 for chars produced from 20--25 mesh coal particles. Finally, the shape of the reactivity patterns changed significantly as we moved from the regime of kinetic control to the regime of intraparticle diffusional limitations.
- Research Organization:
- Rice Univ., Houston, TX (United States). Dept. of Chemical Engineering
- Sponsoring Organization:
- DOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG22-91PC91307
- OSTI ID:
- 6911317
- Report Number(s):
- DOE/PC/91307-T5; ON: DE93004926
- Country of Publication:
- United States
- Language:
- English
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Coal combustion: Effects of process conditions on char reactivity
Coal combustion: Effects of process conditions on char reactivity. Quarterly technical report No. 5, September 1, 1992--December 1, 1992
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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
CARBONACEOUS MATERIALS
CHARS
CHEMICAL ANALYSIS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COAL
COMBUSTION
DATA
DECOMPOSITION
DOCUMENT TYPES
ENERGY SOURCES
EXPERIMENTAL DATA
FOSSIL FUELS
FUELS
GRAVIMETRIC ANALYSIS
HEAT TREATMENTS
HEATING RATE
INFORMATION
KINETICS
MATERIALS
NUMERICAL DATA
OXIDATION
PARTICLE SIZE
PROGRESS REPORT
PYROLYSIS
PYROLYSIS PRODUCTS
QUANTITATIVE CHEMICAL ANALYSIS
REACTION KINETICS
SIZE
TEMPERATURE DEPENDENCE
THERMAL ANALYSIS
THERMAL GRAVIMETRIC ANALYSIS
THERMOCHEMICAL PROCESSES