FGD performance enhancement by hydroclone and recycling steps
AssigneeThe Babcock & Wilcox Company
InventorsPervaje A. Bhat, Dennis W. Johnson
Life of this patent
Estimating the term…
Abstract
A flue gas desulfurization process wherein the liquid bottoms product from the scrubber tower is subject to forced oxidation in a reaction/oxidation tank. Afterwards, this oxidized bottoms product is delivered to hydroclone means for separation into an overflow stream containing an aqueous slurry of mostly fines, fly ash, and unused reagent and an underflow stream containing predominately a gypsum slurry. The overflow stream is initially recycled back to the tank with another stream being subsequently returned or recycled back to the scrubber tower while the underflow stream is dewatered for the removal of the gypsum therein.
Claims16
An apparatus for flue gas desulfurization incorporating a scrubber tower containing a liquid bottoms product therein, wherein the improvement comprises:
- (a) a reaction/oxidation tank into which the liquid bottoms product flows;
- (b) forced oxidation means in said reaction/oxidation tank for oxidizing the liquid bottoms product;
- (c) hydroclone means for receiving the oxidized liquid bottoms product from said reaction/oxidation tank, said hydroclone means separating said oxidized liquid bottoms product into an overflow stream and an underflow stream, said overflow stream primarily comprising fly ash, fines, unused reagent, and organic additives while said underflow stream primarily comprising a concentrated gypsum slurry;
- (d) dewatering means constructed to receive said underflow stream for dewatering and concentrating said gypsum slurry;
- (e) recycle means for recycling contents of said reaction/oxidation tank back to the scrubber tower;
- and,
- (f) return means for initially delivering all or a portion of said overflow stream to said reaction/oxidation tank prior to being recycled back to the scrubber tower.
A method of flue gas desulfurization incorporating a scrubber tower containing a liquid bottoms product therein wherein the improvement comprises the steps of:
- (a) oxidizing the liquid bottoms product generated in the scrubber tower in a reaction/oxidation tank;
- (b) delivering the oxidized liquid bottoms product to a hydroclone assembly;
- (c) separating the oxidized liquid bottoms product in said hydroclone into an overflow stream and an underflow steam, said overflow stream primarily comprising an aqueous slurry of fly ash, fines, organic acids and unused reagent while said underflow stream primarily comprising a gypsum slurry;
- (d) transporting said underflow stream to a dewatering process where gypsum is recovered;
- (e) recycling or returning contents of said reaction/oxidation tank back to said scrubber tower for subsequent spraying onto incoming flue gas;
- and,
- (f) initially returning all or a portion of said overflow stream comprising at least recovered reagent and organic acids to said reaction/oxidation tank prior to recycling said stream to the tower.
Dependencies are inferred from the claim text.