Patent ID: 8147785

Claim:
A method for removing NO X from a flue gas stream comprising injecting ammonia or an ammonia-forming compound into a combustion flue gas stream containing NO X , wherein an excess of ammonia is introduced into the flue gas stream as an agent for reducing the NO X , to yield a flue gas stream containing unreacted residual ammonia and a reduced concentration of NO X ; thereafter injecting hydrogen peroxide into the flue gas stream containing unreacted residual ammonia, the flue gas having a temperature of about 250° F. to about 800° F.,in an amount sufficient to react with residual ammonia present in the flue gas stream, to yield an ammonia-depleted flue gas stream; and contacting the ammonia-depleted flue gas stream with an alkali reagent in an amount sufficient to remove NO X present in the gas stream, yielding a flue gas stream with reduced concentrations of ammonia and NO X .