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U.S. Department of Energy
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Removal of oxides of nitrogen from gases in multi-stage coal combustion

Patent ·
OSTI ID:570519

Polluting NO{sub x} gas values are removed from off-gas of a multi-stage coal combustion process which includes an initial carbonizing reaction, firing of char from this reaction in a fluidized bed reactor, and burning of gases from the carbonizing and fluidized bed reactions in a topping combustor having a first, fuel-rich zone and a second, fuel-lean zone. The improvement by means of which NO{sub x} gases are removed is directed to introducing NO{sub x}-free oxidizing gas such as compressor air into the second, fuel-lean zone and completing combustion with this source of oxidizing gas. Excess air fed to the fluidized bed reactor is also controlled to obtain desired stoichiometry in the first, fuel-rich zone of the topping combustor. 2 figs.

Sponsoring Organization:
USDOE, Washington, DC (United States)
Assignee:
Dept. of Energy, Washington, DC (United States)
Patent Number(s):
US 5,706,645/A/
Application Number:
PAN: 8-635,422
OSTI ID:
570519
Country of Publication:
United States
Language:
English