Abstract: An apparatus for reducing emissions that has a combustion turbine that feeds exhaust into a heat recovery steam generator (or HRSG) casing in which is positioned an emission reduction system featuring, in gas flow sequence, a first reducing reductant injector (RRI1), as in an ammonia injection grid, for providing reducing reductant, preferably ammonia, into turbine exhaust travelling within the HRSG, followed by a first SCR reactor positioned downstream of the first RRI1, followed by one of either (i) a turbulence generator (TG) as in a static mixer, or (ii) a second RRI2 as in a second ammonia injection grid, or (iii) an RRI2 with integrated TG supported on injectors of RRI2, then followed by a second SCR reactor. The emission reduction system preferably is free of a separate body oxidation catalyst or a separate body ammonia slip catalyst in an effort to utilize a limited volume within the HRSG. Methods of assembling and operating the ERS or T-H combination with ERS are also featured.

Abstract: An apparatus for reducing emissions that has a combustion turbine that feeds exhaust into a heat recovery steam generator (or HRSG) casing in which is positioned an emission reduction system featuring, in gas flow sequence, a first reducing reductant injector (RRI1), as in an ammonia injection grid, for providing reducing reductant, preferably ammonia, into turbine exhaust travelling within the HRSG, followed by a first SCR reactor positioned downstream of the first RRI1, followed by one of either (i) a turbulence generator (TG) as in a static mixer, or (ii) a second RRI2 as in a second ammonia injection grid, or (iii) an RRI2 with integrated TG supported on injectors of RRI2, then followed by a second SCR reactor. The emission reduction system preferably is free of a separate body oxidation catalyst or a separate body ammonia slip catalyst in an effort to utilize a limited volume within the HRSG. Methods of assembling and operating the ERS or T-H combination with ERS are also featured.