Maximizing regulatory credits in controlling air pollution

• US 20060042461A1
• Filed: 08/27/2004
• Published: 03/02/2006
• Est. Priority Date: 08/27/2004
• Status: Active Grant

• Current Assignee: General Electric Technology GmbH (General Electric Company)
• Original Assignee: Alstom Technology Ltd. (Alstom SA)
• Inventors: Piche, Stephen, Boyden, Scott A.
• Granted Patent: US 7,323,036 B2
• Time in Patent Office: Days
• US Class Current: 95/1
• CPC Class Codes: B01D 53/346 Controlling the process
• CPC Class Codes: B01D 53/8696 Controlling the catalytic process
• CPC Class Codes: Y10S 55/34 Indicator and controllers
• CPC Class Codes: Y10S 706/906 Process plant

Abstract

A controller directs the operation of an air pollution control (APC) system having one or more controllable operating parameters and a defined operating limit representing a regulatory limit on an allowed amount of pollutant to be emitted by the APC system. An interface receives data representing a value of a regulatory credit available for emitting less of the pollutant than the regulatory limit on the allowed amount of pollutant. A control processor (i) determines a target set point for each of at least one of the one or more controllable operating parameters, which will maximize the regulatory credits earned, based on the received data and (ii) to directs control of each of the at least one controllable operating parameter based on the determined target set point for that parameter.

Claims

1. A controller for directing operation of an air pollution control (APC) system having one or more controllable operating parameters and a defined operating limit representing a regulatory limit on an allowed amount of pollutant to be emitted by the APC system, comprising:

an interface configured to receive data representing a value of a regulatory credit available for emitting less of the pollutant than the regulatory limit on the allowed amount of pollutant; and

a control processor having logic (i) to determine a target set point for each of at least one of the one or more controllable operating parameters, which will maximize the regulatory credits earned, based on the received data and (ii) to direct control of each of the at least one controllable operating parameter based on the determined target set point for that parameter.

2. The controller according to claim 1, wherein:

one of a neural network process model and a non-neural network process model representing a relationship between each of the one or more controllable operating parameters and the emitted pollutant; and

wherein the control processor is configured with the further logic to determine the target set point for each of the at least one controllable operating parameter based also on the one model.

3. The controller according to claim 2, wherein:

the one model includes one of a first principle model, a hybrid model, and a regression model.

4. The controller according to claim 1, wherein:

the APC system has one or more other defined operating limits; and

the directed control of the at least one controllable operating parameter, results in a violation of either at least one of the one or more other defined operating limits, or defined operating limit.

5. The controller according to claim 1, wherein:

the control processor determines the target set points for each of the at least one controllable operating parameter by (i) predicting a value of regulatory credits to be earned by operating the APC system at each multiple different target set points for that parameter, based on the value of the available regulatory credit, and (ii) selecting the target set point from the multiple different set points based on the predicted values of regulatory credits.

6. The controller according to claim 1, wherein:

the control processor determines the target set points for the one or more controllable operating parameter to maximize the value of the regulatory credits to be earned in real time after either (i) receipt of the data representing the value of the available regulatory credit or (ii) receipt of a user instruction to maximize the value of the regulatory credits to be earned.

7. The controller according to claim 1, wherein:

the APC system is a wet flue gas desulfurization (WFGD) system that receives SO₂ laden wet flue gas, expends power to apply oxidation air and limestone slurry to remove SO₂ from the received SO₂ laden wet flue gas, and exhausts desulfurized flue gas;

the pollutant is SO₂;

the one or more controllable operating parameters include a first parameter corresponding to an amount of the applied oxidation air and a second parameter corresponding to an amount of the applied limestone slurry; and

the control processor determines the target set points for the first and the second parameters that will maximize removal of SO₂ from the received SO₂ laden wet flue gas, and thereby maximize the value of regulatory credits.

8. The controller according to claim 1, wherein:

the APC system is a selective catalytic reduction (SCR) system that receives NO_x laden flue gas, applies ammonia and dilution air to remove NO_x from the received NO_x laden flue gas, thereby controlling emissions of NO_x, and exhausts reduced NO_x flue gas;

the pollutant is NO_x;

the one or more controllable operating parameters include a parameter corresponding to an amount of the ammonia applied; and

the control processor determines the target set point for the parameter corresponding to an amount of the ammonia applied that will maximize removal of NO_x from the received NO_x laden flue gas, and thereby maximize the value of regulatory credits.

9. The controller according to claim 1, wherein:

the control processor determines the target set points for the at least one controllable operating parameter based also on other data representing at least one of prior APC system operations and future APC system operations.

10. A method for directing control of an air pollution control (APC) process having one or more controllable operating parameters and a defined operating limit representing a regulatory limit on an allowed amount of pollutant to be emitted by the APC system, comprising:

receiving data representing a value of a regulatory credit available for emitting less of the pollutant than the regulatory limit on the allowed amount of pollutant;

determining a target set point for each of at least one of the one or more controllable operating parameters that will maximize regulatory credits earned, based on the received data; and

directing control of each of the at least one controllable operating parameter based on the determined target set point for that parameter.

11. The controller according to claim 10, wherein:

the target set point for each of the at least one controllable operating parameter is determined based also on one of a neural network process model and a non-neural network process;

wherein the one model represents a relationship between each of the one or more controllable operating parameters and the emitted pollutant.

12. The controller according to claim 11, wherein:

the one model includes one of a first principle model, a hybrid model, and a regression model.

13. The method according to claim 10, wherein:

the APC process has one or more other defined operating limits; and

the directed control of the at controllable operating parameter results in a violation of at least one of the one or more other defined operating limits, or defined operating limit.

14. The method according to claim 10, wherein:

the target set point for each of the at least one controllable operating parameter is determined by (i) predicting a value of regulatory credits to be earned with that parameter at each of multiple different set points, based on the value of the available regulatory credit, and (ii) selecting the target set point for that parameter from the multiple different set points based on the predicted values of regulatory credits.

15. The method according to claim 10, further comprising:

receiving a user instruction to maximize the value of the regulatory credits to be earned;

wherein the target set point for each of the at least one controllable operating parameter is determined in real time after either (i) receipt of the data representing the value of the available regulatory credit or (ii) receipt of the user instruction.

16. The method according to claim 10, wherein:

the APC process is a wet flue gas desulfurization (WFGD) process that expends power to apply oxidation air and limestone slurry to remove SO₂ from SO₂ laden wet flue gas;

the pollutant is SO₂;

the one or more controllable operating parameters include a first parameter corresponding to an amount of the applied oxidation air and a second parameter corresponding to an amount of the applied limestone slurry; and

the target set point for the first and the second parameter is determined so as to maximize removal of SO₂ and thereby maximize the value of regulatory credits earned.

17. The controller according to claim 10, wherein:

the APC process is a selective catalytic reduction (SCR) process that applies ammonia and dilution air to remove NO_x from NO_x laden flue gas, thereby controlling emissions of NO_x, and exhausts reduced NO_x flue gas;

the pollutant is NO_x;

the one or more controllable operating parameters include a parameter corresponding to an amount of the ammonia applied; and

the target set point for the parameter corresponding to an amount of the ammonia applied is determined so as to maximize removal of NO_x from the received NO_x laden flue gas, and thereby maximize the value of regulatory credits.

18. The method according to claim 10, wherein:

the target set points for the at least one controllable operating parameter are determined based also on other data representing at least one of prior APC process performance and future APC process performance.