Process for the combined removal of SO/sub 2/ and NO/sub x/ from flue gas
A process of the simultaneous removal of NO/sub x/ and SO/sub 2/ from a fluid stream itself comprised of NO/sub x/ and SO/sub x/, is described which comprises: (A) contacting the fluid stream in a contacting zone with an aqueous reaction mixture itself comprising an effective amount of an iron (II) chelate of an amino acid moiety having at least one -SH group selected from amino acids, N-substituted amino acids, natural peptides and synthetic peptides, and an alkali which comprises a basic salt selected from the salts of sodium, potassium, lithium, calcium or magnesium, (B) separating the fluid stream from the particulates formed in step (A) which particulates comprise the chelate of the amino acid moiety and fly ash; (C) washing with the particulates of step (B) with a relatively neutral aqueous solution having a pH of between about 5 and 8 with subsequent separation of the aqueous wash and the particulates; (D) subsequently washing the particulates of step (C) with an acidic aqueous solution of a mineral acid; (E) washing of the particulates of step (D) with an alkaline aqueous solution having a pH of between about 9 and 12 with subsequent separation of the aqueous wash and the particulates; (F) adding additional amino acid moiety, iron (II) ion, and an alkali which comprise a basic salt selected from the salts of sodium potassium, lithium, calcium or magnesium to produce an effective concentration of chelating aqueous solution or slurry having a pH of between about 4 to 12; and (G) recycling the aqueous solution of step (F) to the contact zone of step (A).
- Assignee:
- Dept. of Energy, Washington, DC
- Patent Number(s):
- US 4732744
- OSTI ID:
- 5089151
- Resource Relation:
- Patent File Date: Filed date 27 Oct 1986
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
20 FOSSIL-FUELED POWER PLANTS
54 ENVIRONMENTAL SCIENCES
FLUE GAS
ACIDIFICATION
DENITRATION
DESULFURIZATION
NITROGEN OXIDES
REMOVAL
SULFUR DIOXIDE
AIR POLLUTION CONTROL
ALKALI METAL COMPOUNDS
AMINO ACIDS
AQUEOUS SOLUTIONS
CHELATING AGENTS
CHLORIDES
IRON COMPOUNDS
PEPTIDES
RECYCLING
WASHING
CARBOXYLIC ACIDS
CHALCOGENIDES
CHEMICAL REACTIONS
CHLORINE COMPOUNDS
CLEANING
CONTROL
DISPERSIONS
GASEOUS WASTES
HALIDES
HALOGEN COMPOUNDS
MIXTURES
NITROGEN COMPOUNDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
POLLUTION CONTROL
PROTEINS
SOLUTIONS
SULFUR COMPOUNDS
SULFUR OXIDES
TRANSITION ELEMENT COMPOUNDS
WASTES
010800* - Coal
Lignite
& Peat- Waste Management
200202 - Fossil-Fueled Power Plants- Waste Management- Noxious Gas & Particulate Emissions
500200 - Environment
Atmospheric- Chemicals Monitoring & Transport- (-1989)