Importance

Loading Importance Indicators...

Abstract

The present invention relates to methods for selectively reducing NO.sub.x so that nitrogen can be removed from emission effluent streams and NO.sub.x emissions can be reduced to very low levels. In addition, the present invention teaches a method whereby NO.sub.x and SO.sub.x may be simultaneously removed from the effluent stream. The present invention teaches the reduction of NO.sub.x with cyanuric acid. Initially, cyanuric acid is decomposed to form decomposition products. The reaction of cyanuric acid to produce its decomposition products, such as isocyanic acid or related reaction intermediates, takes place in an oxygen-free, fuel rich, decomposition zone with the reaction temperature in the range of from about 1000.degree. F. to about 3000.degree. F. After the cyanuric acid is decomposed in the absence of oxygen, the decomposition stream is mixed with the effluent stream containing NO.sub.x. At this point the oxygen level of the stream must be carefully controlled to provide an excess of oxygen. It may be necessary at this point to inject air into the effluent stream in order to maintain the proper oxygen-rich (fuel-lean) conditions for NO.sub.x reduction. In the second 'reaction zone,' reduction takes place at temperatures of from approximately 1200.degree. F. to approximately 2600.degree. F. The present invention can also be combined with SO.sub.x control technology. Specifically, species used to control SO.sub.x, such as limestone, dolomite, quicklime, and hydrated lime, can be added to the cyanuric acid for injection into the effluent stream. Thus, simultaneous NO.sub.x and SO.sub.x control can be achieved.

Loading the Abstract Image...

First Claim