Ammonia double-alkali process for removing sulfur oxides from stack gases

Patent · Tue Nov 04 04:00:00 EST 1980

OSTI ID:6426117

Campbell, I E; Henderson, J M; Johnson, W; Wetherill, W H

An ammonia-based double-alkali process for removing sulfur oxides from stack gases. In this process, usually continuous, stack gases are contacted with an aqueous wash liquid containing ammonium sulfite as a sulfur oxide reactive compound to form a spent absorbent liquor containing bisulfite, sulfite and sulfate salts of ammonia. A portion of the reactive compound is regenerated by reacting the spent scrubbing liquor with a source of calcium ions, usually limestone. During the regeneration, calcium sulfite solids are precipitated as a by-product, any gypsum solids precipitation during the process being tolerated for a time insufficient to degrade substantially process performance. The resultant calcium solids are separated from the regenerated liquor which is returned for further contact with the stack gases, a portion of these solids being recycled to the regeneration stage. The process is preferably regulated by monitoring and controlling of the calcium concentration of the regenerated liquor, upset conditions being corrected by the addition of make-up ammonia during regeneration of the liquor.

• Assignee: Smelter Control Research Association Inc
• Patent Number(s): US 4231995
• OSTI ID: 6426117
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010800 -- Coal
Lignite
& Peat-- Waste Management
20 FOSSIL-FUELED POWER PLANTS
200202* -- Fossil-Fueled Power Plants-- Waste Management-- Noxious Gas & Particulate Emissions
42 ENGINEERING
424000 -- Engineering-- Pollution Control Equipment-- (1980-1989)
AIR POLLUTION CONTROL
AMMONIUM COMPOUNDS
CHALCOGENIDES
CHEMICAL REACTIONS
CONTROL
DESULFURIZATION
FLUE GAS
FOSSIL-FUEL POWER PLANTS
GASEOUS WASTES
OXIDES
OXYGEN COMPOUNDS
POLLUTION CONTROL
POWER PLANTS
REMOVAL
SULFUR COMPOUNDS
SULFUR OXIDES
THERMAL POWER PLANTS
WASTES