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:
- Pittsburgh Energy Technology Center
- 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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