| 摘要 |
<p>This invention relates to methods and apparatus for reducing NOx in combustion effluent gases which comprise a two-stage injection process. NHi precursors (such as liquid-phase urea or ammonium hydroxide, or the like) are injected into the flue gas at temperatures greater than 1400°F in a first injection zone to reduce NO to nitrogen. This step is followed by injecting a peroxyl initiator, such as a hydrocarbon material (for example, methanol) into the flue gas at temperatures less than 1400°F to oxidize residual NO to NO2 in a second injection zone. NHi precursors and the peroxyl initiator are injected into the flue gas stream in first injection zone (12) and second injection zone (14), respectively, of boiler (10). An injection manifold (16) is supplied by a compressor (18) which provides air to injection nozzle (20).</p> |
