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Process for the removal of acid components and nitrogen oxides from the waste gases of industrial furnaces

Patent 4971777 Issued on November 20, 1990. Estimated Expiration Date: Icon_subject November 14, 2008. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Patent References

Method for removing acidic components including nitrogen oxide from waste gases
Patent #: 4541999
Issued on: 09/17/1985
Inventor: Bechthold ,   et al.

Method for removing nitrogen oxides from waste gases Patent #: 4564510
Issued on: 01/14/1986
Inventor: Bechthold ,   et al.

Inventors

Application

No. 271094 filed on 11/14/1988

US Classes:

423/235, Nitrogen or nitrogenous component423/292Halogen containing

Examiners

Primary: Heller, Gregory A.

Attorney, Agent or Firm

Foreign Patent References

  • 56-37029 JP 04/12/1981

International Classes

C01B 017/00
C01B 021/00

Foreign Application Priority Data

1987-11-19 DE

Abstract

The process removes acid components including sulfur oxides and nitrogen oxides from the exhaust gases of industrial furnaces and includes oxidizing the nitrogen oxide contained in the exhaust gases with the oxygen contained in the exhaust gases at a exhaust gases temperature between 300° and 900° C. before entry of the gases into a first absorption stage, with an addition to the exhaust gases of an organic compound, preferably methanol, as a radical former. After oxidation of nitrogen oxides the exhaust gases undergo a two-stage absorption using aqueous ammonium salt solutions as absorption liquid, whose pH-value is continuously adjusted to less than 5 by addition of aqueous ammonia solution. The mol ratio of NO2 to SO2 in the exhaust gases introduced to the second absorption stage is maintained between 0.01 and 0.5 by diverting a portion of the exhaust gases prior to the first absorption stage to the second absorption stage. The salt solutions obtained thereby are neutralized together and evaporated, whereby the salts so produced, after pelletization or granulation represent a useful fertilizer.

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