Tempered Ammonia Injection For Gas Turbine Selective Catalyst Reduction System

Abstract

The present application provides a selective catalyst reduction system for use with a combustion gas stream of a gas turbine. The selective catalyst reduction system may include an inlet positioned about the gas turbine, a combined ammonia-tempering air injection grid positioned about the inlet, and a catalyst positioned downstream of the combined ammonia-tempering air injection grid. The combined ammonia-tempering air injection grid injects air and ammonia into the combustion gas stream upstream of the catalyst.

I claim: 
     
         1 . A selective catalyst reduction system for use with a combustion gas stream of a gas turbine, comprising:
 an inlet positioned about the gas turbine;   a combined ammonia-tempering air injection grid positioned about the inlet; and   a catalyst positioned downstream of the combined ammonia-tempering air injection grid;   wherein the combined ammonia-tempering air injection grid injects air and ammonia into the combustion gas stream upstream of the catalyst.   
     
     
         2 . The selective catalyst reduction system of  claim 1 , wherein the combined ammonia-tempering air injection grid comprises a plurality of air injection lances. 
     
     
         3 . The selective catalyst reduction system of  claim 2 , wherein the combined ammonia-tempering air injection grid comprises an air source in communication with the plurality of air injection lances. 
     
     
         4 . The selective catalyst reduction system of  claim 2 , wherein the combined ammonia-tempering air injection grid comprises one or more air conduits in communication with the plurality of air injection lances. 
     
     
         5 . The selective catalyst reduction system of  claim 2 , wherein the combined ammonia-tempering air injection grid comprises one or more fans in communication with the plurality of air injection lances. 
     
     
         6 . The selective catalyst reduction system of  claim 2 , wherein the combined ammonia-tempering air injection grid comprises a plurality of ammonia injection lances. 
     
     
         7 . The selective catalyst reduction system of  claim 6 , wherein the plurality of plurality of ammonia injection lances is positioned about the plurality of air injection lances. 
     
     
         8 . The selective catalyst reduction system of  claim 6 , wherein the flow of air from the plurality of air injection lances cools the plurality of ammonia injection lances. 
     
     
         9 . The selective catalyst reduction system of  claim 6 , wherein the combined ammonia-tempering air injection grid comprises an ammonia source in communication with the plurality of ammonia injection lances. 
     
     
         10 . The selective catalyst reduction system of  claim 6 , wherein the combined ammonia-tempering air injection grid comprises one or more ammonia conduits in communication with the plurality of ammonia injection lances. 
     
     
         11 . The selective catalyst reduction system of  claim 1 , further comprising a gas mixer positioned downstream of the combined ammonia-tempering air injection grid. 
     
     
         12 . The selective catalyst reduction system of  claim 1 , wherein the combined ammonia-tempering air injection grid comprises an air conduit and an ammonia conduit. 
     
     
         13 . The selective catalyst reduction system of  claim 12 , wherein the air conduit and the ammonia conduit comprise a merged flow conduit. 
     
     
         14 . The selective catalyst reduction system of  claim 13 , wherein the merged flow conduit is in communication with a plurality of merged flow lances. 
     
     
         15 . A method of operating a selective catalyst reduction system with a combustion gas stream of a gas turbine engine, comprising:
 flowing the combustion gas stream into the selective catalyst reduction system;   injecting a cooling air stream into the combustion gas stream about an inlet of the selective catalyst reduction system;   injecting an ammonia stream into the combustion gas stream about an inlet of the selective catalyst reduction system;   mixing the combustion gas stream, the cooling air stream, and the ammonia stream; and   reacting the mixed stream with a catalyst.   
     
     
         16 . A combined ammonia-tempering air injection grid for use about an inlet of a selective catalyst reduction system, comprising:
 a plurality of air injection lances positioned about the inlet for providing a flow of air; and   a plurality of ammonia injection lances positioned about the inlet for providing a flow of ammonia;   wherein the plurality of ammonia injection lances are positioned about the plurality of air injection lances such that the flow of air cools the plurality of ammonia injection lances.   
     
     
         17 . The combined ammonia-tempering air injection grid of  claim 16 , further comprising an air source and a fan in communication with the plurality of air injection lances. 
     
     
         18 . The combined ammonia-tempering air injection grid of  claim 16 , further comprising an ammonia source in communication with the plurality of ammonia injection lances. 
     
     
         19 . The combined ammonia-tempering air injection grid of  claim 16 , further comprising an air conduit and an ammonia conduit. 
     
     
         20 . The combined ammonia-tempering air injection grid of  claim 19 , wherein the air conduit and the ammonia conduit comprise a merged flow conduit.