System and method for emissions control in gas turbine systems

1. A system comprising:

an emissions control system, comprising a processor programmed to

receive one or more selective catalytic reduction (SCR) operating conditions for an SCR system, wherein the SCR system is included in an aftertreatment system for an exhaust stream;

receive one or more gas turbine operating conditions for a gas turbine engine, wherein the gas turbine engine is configured to direct the exhaust stream into the aftertreatment system;

derive an ammonia (NH 3 ) flow to the SCR system based on an SCR model and the one or more SCR operating conditions;

derive a nitrogen oxide (NO)/nitrogen oxides (NO x ) ratio; and

derive a fuel split for the gas turbine engine based on the NH3 flow, the NO/NO x ratio or a combination thereof; and

control the gas turbine engine based on the derived fuel split.

2. The system of claim 1 comprising;

a bottoming cycle configured to receive the exhaust stream and to convert the exhaust stream into a mechanical or electrical power, wherein the aftertreatment system is included in the bottoming cycle.

3. The system of claim 1 , wherein the emission control system comprises an aftertreatment controller and a gas turbine controller, and wherein the aftertreatment controller is configured to receive the one or more SCR system operating conditions; and to derive the NH 3 flow to the SCR; and wherein the gas turbine controller is configured to receive the one or more gas turbine operating conditions; to derive the NO/NOx ratio; and to derive the fuel split for the gas turbine engine.

4. The system of claim 1 , wherein the processor is programmed to derive the NO/NOX ratio by executing an SCR map.

5. The system of claim 1 , wherein the processor is programmed to derive the NH3 flow by using a NH3 slip setpoint and the SCR model as inputs.

6. The system of claim 1 , wherein the processor is programmed to derive the NH3 flow by using a NH3 slip setpoint and a measured NH3 slip as inputs.

7. The system of claim 1 , wherein the processor is programmed to execute an estimator system configured to update the SCR model based on one or more measured outputs of the aftertreatment system.

8. The system of claim 7 , wherein the processor is programmed to update the SCR model by updating one or more parameters of the SCR model.

9. The system of claim 8 , wherein the one or more parameters comprise characteristics of a catalyst used in the SCR system.

10. A method comprising:

receiving one or more selective catalytic reduction (SCR) system operating conditions for an SCR system, wherein the SCR system is included in an aftertreatment system for an exhaust stream;

receiving one or more gas turbine operating conditions for a gas turbine engine, wherein the gas turbine engine is configured to provide the exhaust stream into the aftertreatment system;

deriving an ammonia (NH 3 ) flow to the SCR system based on an SCR model and the one or more SCR system operating conditions;

deriving a nitrogen oxide (NO)/nitrogen oxides (NO x ) ratio; and

deriving a fuel split for the gas turbine engine based on the NH 3 flow, the NO/NO x ratio, or a combination thereof.

11. The method of claim 10 , wherein deriving the NO/NO x ratio comprises deriving the NO/NO x ratio by executing an SCR map.

12. The method of claim 10 , wherein deriving the NH 3 flow comprises deriving the NH 3 flow by using a NH 3 slip setpoint and the SCR model as inputs.

13. The method of claim 10 , wherein deriving the NH 3 flow comprises deriving the NH 3 flow by using a NH 3 slip setpoint and a measured NH 3 slip as inputs.

14. The method of claim 10 , comprising executing an estimator system to update the SCR model based on one or more measured outputs of the aftertreatment system.

15. The method of claim 14 , wherein executing the estimator system to update the SCR modelcomprises executing the estimator system to update one or more parameters of the SCR model.

16. A system comprising:

a gas turbine engine configured to combust a fuel to produce a first power;

a bottoming cycle fluidly coupled to the gas turbine engine and configured to receive an exhaust stream of the gas turbine engine to produce a second power;

a selective catalyst reduction (SCR) system disposed in the bottoming cycle and configured to receive the exhaust stream and to remove NOx from the exhaust stream; and

a controller comprising a processor programmed to

receive one or more SCR system operating conditions;

receive one or more gas turbine operating conditions;

derive an ammonia (NH 3 ) flow to the SCR system based on an SCR model and the one or more SCR system operating conditions;

derive a nitrogen oxide (NO)/nitrogen oxides (NOx) ratio; and

derive a fuel split for the gas turbine engine based on the NH 3 flow, the NO/NO x ratio, or a combination thereof.

17. The system of claim 16 , wherein the processor is programmed to derive the NH 3 flow by using a NH 3 slip setpoint and the SCR model as inputs.

18. The system of claim 16 , wherein the processor is programmed to derive the NH 3 flow by using a NH 3 slip setpoint and a measured NH 3 slip as inputs.

19. The system of claim 16 , wherein the processor is programmed to execute an estimator system configured to update the SCR model based on one or more measured outputs of the SCR system.

20. The system of claim 16 , wherein the controller comprises an aftertreatment controller and a gas turbine controller, and wherein the aftertreatment controller is configured to receive the one or more SCR system operating conditions; and to derive the NH 3 flow to the SCR system; and wherein the gas turbine controller is configured to receive the one or more gas turbine operating conditions; to derive the NO/NO x ratio; and to derive the fuel split for the gas turbine engine.