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US 6,206,949 B1Granted
NOx reduction using coal based reburning
AssigneePraxair Technology, Inc.
InventorsHisashi Kobayashi, Lawrence E. Bool, III, Michael Francis Riley
Life of this patent
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Abstract
A method for reducing the NOx content of combustion gases from combustion in a commercial furnace wherein hot oxygen and carbonaceous fuel such as pulverized coal react to form a fuel-rich gas phase mixture which is then used to reduce NOx to nitrogen gas.
Claims9
A method for reducing the NOx content of combustion gases from a combustion reaction comprising:
- (A) combusting fuel and oxidant to generate heat and to form combustion gases comprising NOx;
- (B) heating oxygen to a temperature within the range of from 1000° F. to 3000° F. to form hot oxygen;
- (C) mixing the hot oxygen with granular carbonaceous fuel containing volatiles to form a mixture having a stoichiometric ratio less than 1.0, devolatizing the granular carbonaceous fuel within the mixture, and reacting hot oxygen with volatiles and granular carbonaceous fuel within the mixture to form a fuel-rich gas phase mixture containing hydrocarbon radicals;
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- (D) contacting the combustion gases with the fuel-rich gas phase mixture and reacting hydrocarbon radicals of the fuel-rich gas phase mixture with NOx of the combustion gases to form nitrogen gas.
2 more elements
Dependencies are inferred from the claim text.