Sorbent performance in fluidized-bed coal combustion
The sulfation behavior of natural limestones and dolomites has been assessed using a bench scale fluidized bed reactor under conditions which are applicable to bubbling atmospheric fluidized bed condition. By increasing the temperature or reducing the CO{sub 2} partial pressure in the calcining gas, both precalcined and uncalcined sorbents exhibited relatively similar behavior on sulfation. Under these conditions calcination was relatively fast and therefore did not influence the overall sulfation process. When preparing precalcined sorbents, their reactivities towards SO{sub 2} depended on the calcining conditions, in particular on the CO{sub 2} concentration in the calcining gas and the calcining temperature. The apparent effects of calcining conditions on the subsequent sulfation behavior were directly related to the physical structure of the solid, which changes as a consequence of sintering. For a particular sorbent there is an optimum pore size beyond which the sulfur uptake begins to decrease. The low sulfur uptake at high temperatures was due to early pore blockage which restricted the transport of SO{sub 2} into the particle. Higher calcium utilization was achieved using impure limestones. When distributed uniformly within the particles, impurities dilute the CaO concentration and help to delay pore blockage upon reaction with SO{sub 2}. In the sulfation of uncalcined sorbents, the presence of impurities will increase the overall rate of calcination. In addition, some impurities will affect the sintering process and ultimately produce a favorable solid structure for sulfation. It can be concluded that the chemical composition of a sorbent should be considered in addition to its physical properties in selecting suitable candidates for reducing SO{sub 2} emissions from fluidized bed combustion.
- Research Organization:
- Pennsylvania State Univ., University Park, PA (USA)
- OSTI ID:
- 5750784
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
DOLOMITE
SULFIDATION
FLUIDIZED-BED COMBUSTORS
DESULFURIZATION
LIMESTONE
ADSORBENTS
AIR POLLUTION ABATEMENT
ATMOSPHERIC PRESSURE
BENCH-SCALE EXPERIMENTS
CALCINATION
CALCIUM OXIDES
CARBON DIOXIDE
CHEMICAL COMPOSITION
COAL
FLOW BLOCKAGE
FLUIDIZED-BED COMBUSTION
GAS FLOW
IMPURITIES
PARTIAL PRESSURE
PHYSICAL PROPERTIES
POROSITY
QUANTITY RATIO
REMOVAL
SINTERING
SULFUR DIOXIDE
TEMPERATURE DEPENDENCE
ALKALINE EARTH METAL COMPOUNDS
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBON OXIDES
CARBONACEOUS MATERIALS
CARBONATE MINERALS
CARBONATE ROCKS
CARBONATES
CHALCOGENIDES
CHEMICAL REACTIONS
COMBUSTION
COMBUSTORS
DECOMPOSITION
ENERGY SOURCES
FABRICATION
FLUID FLOW
FOSSIL FUELS
FUELS
MAGNESIUM CARBONATES
MAGNESIUM COMPOUNDS
MATERIALS
MINERALS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
POLLUTION ABATEMENT
PYROLYSIS
ROCKS
SEDIMENTARY ROCKS
SULFUR COMPOUNDS
SULFUR OXIDES
THERMOCHEMICAL PROCESSES
014000* - Coal
Lignite
& Peat- Combustion
010800 - Coal
Lignite
& Peat- Waste Management