Experimental study and mathematical modeling of spent oil shale block combustion - with application to modified in-situ retorting
This study examines the combustion behavior of spent oil shale blocks after pyrolysis. The experiments simulated in situ retorting by minimizing radiation. The effects of shale grade (from 25 to 250 L/tonne), block size (1 to 10 cm in diameter), and combustion gas composition (5 to 21% O/sub 2/, 0 to 50% H/sub 2/O) were examined. This study confirms the important role of gasification of the char by CO/sub 2/ released from decomposition of carbonate minerals and explores the transition to that mechanism from the initial direct attack of O/sub 2/ on char. Experiments also showed that steam has some positive effect on combustion rates for medium and rich shales, but the effect was limited. The H/sub 2/O-C gasification reaction was believed to be the main cause for the above effect. Mathematical models based on intrinsic kinetics and gaseous diffusion in porous medium were developed to describe and predict these combustion phenomena. The chemical reactions considered were: the direct oxidation of char, the CO/sub 2/-C and H/sub 2/O-C gasification reactions, the gaseous oxidation of hydrogen and carbon monoxide, carbonate decomposition reactions, water-gas shift reaction, and the residual hydrogen release reaction.
- OSTI ID:
- 6191998
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
040401* -- Oil Shales & Tar Sands-- In Situ Methods
True & Modified
BITUMINOUS MATERIALS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CARBONACEOUS MATERIALS
CHALCOGENIDES
CHARS
CHEMICAL REACTIONS
COMBUSTION
DECOMPOSITION
ENERGY SOURCES
FOSSIL FUELS
FUELS
GASIFICATION
IN-SITU PROCESSING
IN-SITU RETORTING
MATERIALS
MATHEMATICAL MODELS
OIL SHALES
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PROCESSING
PYROLYSIS
PYROLYSIS PRODUCTS
RETORTING
STEAM
THERMOCHEMICAL PROCESSES