X-ray-absorption spectroscopic investigation of alkali and alkaline earth catalysts in coal gasification. Final report, January 1987-September 1989
The structures of alkali and alkaline-earth metal catalyst species in lignite and polymer chars and during pyrolysis pretreatment and char gasification have been investigated using ambient and newly-developed, in situ XAFS spectroscopic techniques. The XAFS data, which were obtained at the Stanford Synchrotron Radiation Laboratory, were supplemented by char characterization and reactivity measurements made at the Pennsylvania State University. The findings of the investigation are as follows: (i) the catalytic species, as introduced to the char or lignite, is an atomically-dispersed, metal-ion-oxygen-anion complex, and remains a metal-oxygen complex throughout pyrolysis and gasification; (ii) the catalyst species transforms to a bulk oxide species during pyrolysis pretreatment; (iii) during gasification, the catalyst species rapidly transforms to bulk alkali carbonate in the case of the alkali-metal species and slowly to calcium oxide in the case of the calcium species; (iv) higher catalyst loadings results in an increased number of catalytic sites, rather than any structural variation of the catalyst site due to concentration effects; and (v) reaction of alkali with aluminosilicates (from clays) or silica is the major catalyst poisoning reaction, unless the coal is demineralized in which case the alkali may react with residual halide from HCl or HF used to clean the coal. Such poisoning reactions were not demonstrated for calcium-oxygen species.
- Research Organization:
- Kentucky Univ., Lexington, KY (USA). Inst. for Mining and Minerals Research
- OSTI ID:
- 6621729
- Report Number(s):
- PB-90-247362/XAB; CNN: GRI-5086-260-1627; TRN: 91-010597
- Resource Relation:
- Other Information: See also PB--87-215729
- Country of Publication:
- United States
- Language:
- English
Similar Records
Importance of catalysis and carbon active sites in lignite char gasification
Importance of active sites for char gasification in oxygen (air) and carbon dioxide. Annual report, October 1983-September 1984
Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
01 COAL, LIGNITE, AND PEAT
ALKALI METALS
X-RAY SPECTROSCOPY
ALKALINE EARTH METALS
COAL GASIFICATION
CATALYSTS
ABSORPTION SPECTROSCOPY
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
CALCIUM OXIDES
CARBONATES
CATALYTIC EFFECTS
CHARS
COMPLEXES
DEMINERALIZATION
HALIDES
LIGNITE
OXIDES
POISONING
POLYMERS
PROGRESS REPORT
PYROLYSIS
SURFACE PROPERTIES
SYNCHROTRON RADIATION
BREMSSTRAHLUNG
BROWN COAL
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONACEOUS MATERIALS
CHALCOGENIDES
CHEMICAL REACTIONS
COAL
DECOMPOSITION
DOCUMENT TYPES
ELECTROMAGNETIC RADIATION
ELEMENTS
ENERGY SOURCES
FOSSIL FUELS
FUELS
GASIFICATION
HALOGEN COMPOUNDS
MATERIALS
METALS
OXYGEN COMPOUNDS
PYROLYSIS PRODUCTS
RADIATIONS
SEPARATION PROCESSES
SPECTROSCOPY
THERMOCHEMICAL PROCESSES
400101* - Activation
Nuclear Reaction
Radiometric & Radiochemical Procedures
010404 - Coal
Lignite
& Peat- Gasification