Method for removing sulfur dioxide from combustion exhaust gas

Patent · Tue Jun 01 04:00:00 EDT 1976

OSTI ID:7236867

Morita, T; Kobayashi, A; Funahashi, I; Matsuda, T; Naoki, M; Kawamata, N; Fukui, J

Sulfur dioxide can be removed from a combustion exhaust gas and converted to gypsum by first scrubbing a sulfur dioxide-containing combustion exhaust gas with an aqueous alkali sulfite solution to form an alkali bisulfite-containing aqueous solution and then treating, within a closed system, the thus formed aqueous bisulfite solution with a calcium compound. The efficiency of the sulfur dioxide removal can be increased greatly by adding a portion of alkali sulfite aqueous solution circulating in the system to at least a portion of filtrate from the gypsum separation process to precipitate metallic ionic impurities contained in the filtrate in the form of salts and separate these salts by filtration, and then recirculating the filtrate from the salt separation process to the absorption system. 18 Claims, 2 Drawing Figures.

• Assignee: Kureha Kagaku Kogyo Kabushiki Kaisha
• Patent Number(s): US 3961021
• OSTI ID: 7236867
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400105 -- Separation Procedures
500200* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
CALCIUM COMPOUNDS
CALCIUM SULFATES
CHALCOGENIDES
COMBUSTION PRODUCTS
EXHAUST GASES
GASEOUS WASTES
GYPSUM
MINERALS
OXIDES
OXYGEN COMPOUNDS
PURIFICATION
REMOVAL
SEPARATION PROCESSES
SORPTIVE PROPERTIES
SULFATES
SULFUR COMPOUNDS
SULFUR DIOXIDE
SULFUR OXIDES
SURFACE PROPERTIES
WASTES