Importance of active sites for char gasification in oxygen (air) and carbon dioxide. Annual report, October 1983-September 1984
Nonisothermal gasification reactivities in air (5 K/min) and the isothermal reactivities in carbon dioxide (973 and 1073 K) of a Montana lignite and chars, prepared by slow and rapid pyrolysis of the raw and suitably pretreated lignite, were measured by thermogravimetric analysis. The coal pretreatment involved demineralization, ion exchange with ammonium acetate, and subsequent ion exchange with calcium acetate. Reactivity data show the marked influence of the presence of calcium species on reactivity in both air and carbon dioxide. However, there appears to be a saturation effect. That is, after a certain quantity of calcium ion is added (about 0.49 mmole/g) further addition does not have an appreciable influence on the measured gasification reactivity. In an attempt to measure the concentration of carbon-active sites, oxygen chemisorption capacities of several prepared chars were determined at 375 K and 0.1 MPa air. It is noted that the active area does reflect the order of reactivity in both air and carbon dioxide. Highly reactive chars chemisorb large quantities of oxygen at the conditions used, indicating high activity.
- Research Organization:
- Pennsylvania State Univ., University Park (USA). Dept. of Materials Science and Engineering
- OSTI ID:
- 5947778
- Report Number(s):
- PB-85-155984/XAB
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
010404* -- Coal
Lignite
& Peat-- Gasification
BROWN COAL
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CARBONACEOUS MATERIALS
CHALCOGENIDES
CHARS
CHEMICAL REACTIONS
CHEMISORPTION
COAL
COAL GASIFICATION
COAL PREPARATION
DEMINERALIZATION
ELEMENTS
ENERGY SOURCES
FOSSIL FUELS
FUELS
GASIFICATION
KINETICS
LIGNITE
MATERIALS
NONMETALS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PYROLYSIS PRODUCTS
REACTION KINETICS
SEPARATION PROCESSES
SORPTION
THERMOCHEMICAL PROCESSES