Method of removing oxides of sulfur and oxides of nitrogen from exhaust gases
- Bethel Park, PA
A continuous method is presented for removing both oxides of sulfur and oxides of nitrogen from combustion or exhaust gases with the regeneration of the absorbent. Exhaust gas is cleaned of particulates and HCl by a water scrub prior to contact with a liquid absorbent that includes an aqueous solution of bisulfite and sulfite ions along with a metal chelate, such as, an iron or zinc aminopolycarboxylic acid. Following contact with the combustion gases the spent absorbent is subjected to electrodialysis to transfer bisulfite ions into a sulfuric acid solution while splitting water with hydroxide and hydrogen ion migration to equalize electrical charge. The electrodialysis stack includes alternate layers of anion selective and bipolar membranes. Oxides of nitrogen are removed from the liquid absorbent by air stripping at an elevated temperature and the regenerated liquid absorbent is returned to contact with exhaust gases for removal of sulfur oxides and nitrogen oxides.
- Research Organization:
- USDOE Pittsburgh Energy Technology Center (PETC), PA (United States)
- Assignee:
- United States of America as represented by United States (Washington, DC)
- Patent Number(s):
- US 4615780
- OSTI ID:
- 866005
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
removing
oxides
sulfur
nitrogen
exhaust
gases
continuous
combustion
regeneration
absorbent
gas
cleaned
particulates
hcl
water
scrub
prior
contact
liquid
aqueous
solution
bisulfite
sulfite
metal
chelate
iron
zinc
aminopolycarboxylic
acid
following
spent
subjected
electrodialysis
transfer
sulfuric
splitting
hydroxide
hydrogen
migration
equalize
electrical
charge
stack
alternate
layers
anion
selective
bipolar
membranes
removed
air
stripping
elevated
temperature
regenerated
returned
removal
liquid absorbent
nitrogen oxide
electrical charge
sulfur oxide
sulfur oxides
alternate layers
acid solution
nitrogen oxides
exhaust gases
aqueous solution
elevated temperature
sulfuric acid
combustion gases
carboxylic acid
combustion gas
exhaust gas
metal chelate
splitting water
removing oxide
removing oxides
continuous method
aminopolycarboxylic acid
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