초록 ▼

A steam and gas turbine (STAG) plant employs a catalyst in a heat recovery steam generator to react injected ammonia with NOx from the combustor of the gas turbine to reduce atmospheric emission of NOx from the system. Rapid control of ammonia injection is achieved using a prediction of the NOx bein

A steam and gas turbine (STAG) plant employs a catalyst in a heat recovery steam generator to react injected ammonia with NOx from the combustor of the gas turbine to reduce atmospheric emission of NOx from the system. Rapid control of ammonia injection is achieved using a prediction of the NOx being generated in dependence upon the operating conditions of the combustor. A trimming signal from a measurement of NOx being emitted from the heat recovery steam generator downstream of the catalyst is employed to complete the NOx control loop.

대표청구항 ▼

Apparatus for controlling admission of ammonia into an exhaust gas stream from a combustion process upstream of a catalyst for reacting with NOx in the catalyst, comprising: means for predicting a predicted amount of NOx produced by said combustion process: means for injecting said ammonia into said

Apparatus for controlling admission of ammonia into an exhaust gas stream from a combustion process upstream of a catalyst for reacting with NOx in the catalyst, comprising: means for predicting a predicted amount of NOx produced by said combustion process: means for injecting said ammonia into said exhaust gas stream at a rate effective to react in said catalyst with said predicted amount of NOx to produce a level of NOx downstream of said catalyst equal to a NOx setpoint; means for measuring an amount of NOx downstream of said catalyst to produce a measured NOx signal; means for comparing said measured NOx signal with said setpoint to produce a NOx error signal; and means for correcting said rate in dependence on said error to adjust said NOx downstream of said catalyst toward said setpoint. A method for controlling NOx emissions in a combined cycle plant of the type having a gas turbine producing a heated exhaust and a heat recovery steam generator through which said heated exhaust is passed for generation of steam therein, and a catalyst in said heat recovery steam generator disposed for the passage of said exhaust therethrough to produce nitrogen and water for reduction of NOx in an effluent of said heat recovery steam generator, comprising: generating a predicted NOx signal based on at least a pressure, a temperature, an air flow and a fuel flow in said gas turbine; injecting an amount of ammonia responsive to said predicted NOx signal into said heated exhaust to react with said NOx to reduce said NOx downstream of said catalyst to a NOx setpoint; producing a measured NOx signal related to an amount of NOx downstream of said catalyst; producing a NOx error signal in dependence on a difference between said measured NOx signal and said setpoint; and adjusting the injecting of ammonia in response to said error signal in a direction and an amount to reduce said error signal.