Sorbent performance in fluidized-bed coal combustion

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1988

OSTI ID:5750784

Haji Sulaiman, M Z

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
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010800 -- Coal
Lignite
& Peat-- Waste Management
014000* -- Coal
Lignite
& Peat-- Combustion
ADSORBENTS
AIR POLLUTION ABATEMENT
ALKALINE EARTH METAL COMPOUNDS
ATMOSPHERIC PRESSURE
BENCH-SCALE EXPERIMENTS
CALCINATION
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CARBONACEOUS MATERIALS
CARBONATE MINERALS
CARBONATE ROCKS
CARBONATES
CHALCOGENIDES
CHEMICAL COMPOSITION
CHEMICAL REACTIONS
COAL
COMBUSTION
COMBUSTORS
DECOMPOSITION
DESULFURIZATION
DOLOMITE
ENERGY SOURCES
FABRICATION
FLOW BLOCKAGE
FLUID FLOW
FLUIDIZED-BED COMBUSTION
FLUIDIZED-BED COMBUSTORS
FOSSIL FUELS
FUELS
GAS FLOW
IMPURITIES
LIMESTONE
MAGNESIUM CARBONATES
MAGNESIUM COMPOUNDS
MATERIALS
MINERALS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PARTIAL PRESSURE
PHYSICAL PROPERTIES
POLLUTION ABATEMENT
POROSITY
PYROLYSIS
QUANTITY RATIO
REMOVAL
ROCKS
SEDIMENTARY ROCKS
SINTERING
SULFIDATION
SULFUR COMPOUNDS
SULFUR DIOXIDE
SULFUR OXIDES
TEMPERATURE DEPENDENCE
THERMOCHEMICAL PROCESSES