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US 4,389,381 AGranted
Limestone calcination
AssigneeBattelle Development Corporation
InventorSalvatore T. Dinovo
Life of this patent
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Abstract
Calcination of limestone to form a finely divided lime product without substantial contamination by impurities (especially carbon and ash) is accomplished in a secondary fluidized bed with reaction heat provided by recirculating entrained particles from a primary multisolid fluidized bed combustor.
Claims4
A method for producing a finely-divided lime powder substantially free of ash from a limestone raw material which comprises
- (A) generating heat from the combustion of fuel in a primary, entrained-bed combustor having relatively fine particles entrained in a primary fluidizing gas,
- (B) transferring heat of combustion of the fuel to the fine, entrained-bed particles in the combustor,
- (C) circulating at least a portion of the heated, fine, entrained-bed particles to an external, secondary fluidized bed,
- (D) removing impurities from the portion of heated, fine, entrained-bed particles prior to entry in the secondary fluidized bed,
- (E) introducing particulate limestone and a secondary fluidizing gas into the secondary fluidized bed such that the limestone comes into contact with the heated, fine, entrained-bed particles thereby heating the particulate limestone and decomposing it to particulate lime,
- (F) recycling the relatively cool, fine, entrained-bed particles from the secondary fluidized bed to the primary entrained-bed combustor, and
- (G) recovering the particulate lime from the secondary fluidized bed.
4 more elements
Dependencies are inferred from the claim text.