IMPROVED NOX REMOVAL METHOD

The present invention relates to an improved method for NOx removal from flue or waste gas streams in incinerators, waste treatment plants or kilns with wet caustic scrubbers or wet ionizing scrubbers. The present method reduces the operating costs by significantly reducing the amount of ozone required to lower NOx emissions to a certain limit. In accordance with the method of the invention, ozone is injected into the flue gas pipework and/or the APC downstream of the incinerator unit, waste treatment unit or kiln and upstream of a wet caustic scrubber or wet ionizing scrubber. A sub-stoichiometric amount of ozone is utilized such that NO is selectively oxidized by the ozone to NO2, a water-soluble species, rather than being first oxidized to NO2, and then N2O5 as practiced in the prior art. NO2 is water soluble and is readily removed in a scrubbing operation.