Patent ID: 7780934
Filing Date: 2010-08-24
Classification: B01D

Abstract:
1. A method for reducing ammonia slip in flue gas of a fossil fuel burning power plant, the power plant having an oxides of nitrogen (NOx) reducing system and a fly ash collecting device, wherein ammonia is used for reducing the levels of NOx , the method comprising: adding ammonia from an ammonia addition station to the flue gas to reduce oxides of nitrogen (NOx); providing a chemical reagent addition system downstream from the ammonia addition station; and adding an oxidizing chemical reagent from the chemical reagent addition system to form an ammonia oxidation zone in the flue gas exhaust duct upstream of the fly ash collecting device such that the flue gasses exiting the ammonia oxidation zone have a residual ammonia concentration of less than about 20 ppm wherein the chemical reagent is selected from a group of oxidizing compounds consisting of chlorine, fluorine, and bromine compounds.