Fly-ash recycle in dry scrubbing. Journal article

Technical Report · Wed Jan 01 04:00:00 EST 1986

OSTI ID:5601647

Jozewicz, W; Rochelle, G T

The paper describes the effects of fly ash recycle in dry scrubbing. (Previous workers have shown that the recycle of product solids improves the utilization of slaked lime--Ca(OH){sub 2}--for sulfur dioxide (SO{sub 2}) removal by spray dryers with bag filters.) In laboratory-scale experiments with a packed-bed reactor, utilization was increased several-fold when the Ca(OH){sub 2} was first slurried with one of several different fly ashes. The enhancement increased with the higher loading of fly ash--g fly ash/g Ca(OH){sub 2}. Much higher Ca(OH){sub 2} utilization was achieved when silic acid was used instead of fly ash. Scanning electron microscopy supports the explanation that Ca(OH){sub 2} and silica dissolve and reprecipitate as a more reactive calcium silicate. Other major constituents of fly ash have less or no effect at all on Ca(OH){sub 2} utilization. The amount of calcium in the fly ash did not affect the overall SO{sub 2} removal after Ca(OH){sub 2} was added. Slurrying for longer than 2 hours at higher than 60 C can improve the utilization of Ca(OH){sub 2} slurried with fly ash.

• Research Organization: Texas Univ., Austin, TX (United States). Dept. of Chemical Engineering
• OSTI ID: 5601647
• Report Number(s): PB-91-182048/XAB
• Country of Publication: United States
• Language: English

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ADSORBENTS
AEROSOL WASTES
AIR POLLUTION CONTROL
ALKALINE EARTH METAL COMPOUNDS
ASHES
BENCH-SCALE EXPERIMENTS
CALCIUM COMPOUNDS
CALCIUM HYDROXIDES
CALCIUM OXIDES
CALCIUM SILICATES
CHALCOGENIDES
CHEMICAL REACTIONS
CONTROL
DESULFURIZATION
DISPERSIONS
DRY SCRUBBERS
DRYING
ELECTRON MICROSCOPY
EQUIPMENT
FLUE GAS
FLY ASH
GASEOUS WASTES
HYDROGEN COMPOUNDS
HYDROXIDES
MICROSCOPY
MINERALS
MIXTURES
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
POLLUTION CONTROL
POLLUTION CONTROL EQUIPMENT
RECYCLING
RESIDUES
SCANNING ELECTRON MICROSCOPY
SCRUBBERS
SILICA
SILICATES
SILICON COMPOUNDS
SILICON OXIDES
SLURRIES
SPRAY DRYING
SULFUR COMPOUNDS
SULFUR DIOXIDE
SULFUR OXIDES
SUSPENSIONS
WASTE PRODUCT UTILIZATION
WASTES