Patent ID: 6197268
Filing Date: 2001-03-06
Classification: B01D

Abstract:
A process for removing at least one nitrogen oxide from a gas stream comprising the steps:(a) contacting said gas stream with a nitrogen-based reducing agent at a temperature in the range of about 150 to about 1300.degree. C., thereby converting part of said at least one nitrogen oxide to nitrogen and producing a waste gas containing residual nitrogen oxide;(b) contacting said waste gas with ozone, thereby converting at least part of said residual nitrogen oxide to nitric acid, nitric acid precursors or mixtures thereof; and(c) simultaneously along with step (b), contacting said nitric acid, nitric acid precursors or mixtures thereof with an aqueous medium having a pH greater than 7 and at a temperature in the range of about 25.degree. to about 125.degree. C. in the presence of a catalyst thereby converting said nitric acid, nitric acid precursors or mixtures thereof to nit e salt and scrubbing said nitrate salt from said waste gas.