Sulfur dioxide removal process with gypsum and magnesium hydroxide production

Patent · Tue Jan 28 00:00:00 EST 1992

OSTI ID:5427135

Benson, L B

This patent describes improvement in a method for removing sulfur dioxide from flue gases wherein the flue gases are contacted in a wet scrubbing unit, in the absence of any substantial amount of calcium components, with an aqueous solution of magnesium components and magnesium sulfite produced, with aqueous solution, following the contact, collected and recycled to the wet scrubber for further contact with flue gases, and subjecting a portion of the aqueous discharge from the scrubbing unit, containing magnesium sulfite, to oxidation in an oxidation unit. The improvement comprises: adding calcium sulfate to the portion of aqueous discharge containing magnesium sulfite prior to oxidation in the oxidation unit to form an oxidized aqueous effluent containing calcium sulfate solids and dissolved magnesium sulfate; passing the oxidized aqueous effluent to a regeneration tank; adding lime to the regeneration tank to precipitate gypsum from and form an aqueous magnesium hydroxide suspension in the oxidized aqueous effluent; separating the precipitated gypsum from the aqueous magnesium hydroxide suspension; and returning at least a portion of the separated precipitated gypsum to the oxidizing unit as the added calcium sulfate.

• Assignee: Dravco Lime Co., Pittsburgh, PA (United States)
• Patent Number(s): US 5084255; A
• Application Number: PPN: US 7-675418
• OSTI ID: 5427135
• Resource Relation: Patent File Date: 26 Mar 1991
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
54 ENVIRONMENTAL SCIENCES
FLUE GAS
DESULFURIZATION
SULFUR DIOXIDE
REMOVAL
AQUEOUS SOLUTIONS
CALCIUM
GYPSUM
MAGNESIUM HYDROXIDES
MAGNESIUM SLURRY SCRUBBING PROCESS
OXIDATION
PRECIPITATION
PRODUCTION
REGENERATION
SEPARATION PROCESSES
SULFITES
TANKS
ALKALINE EARTH METAL COMPOUNDS
ALKALINE EARTH METALS
CHALCOGENIDES
CHEMICAL REACTIONS
CONTAINERS
DISPERSIONS
ELEMENTS
GASEOUS WASTES
HYDROGEN COMPOUNDS
HYDROXIDES
MAGNESIUM COMPOUNDS
METALS
MINERALS
MIXTURES
OXIDES
OXYGEN COMPOUNDS
SOLUTIONS
SULFATE MINERALS
SULFUR COMPOUNDS
SULFUR OXIDES
WASTES
010800* - Coal
Lignite
& Peat- Waste Management
540120 - Environment
Atmospheric- Chemicals Monitoring & Transport- (1990-)