Method and system for combustion control for gas turbine system with exhaust gas recirculation

Patent metadata

Field	Value
Publication number	US-10060359-B2
Application number	US-201514745095-A
Country	US
Kind code	B2
Filing date	Jun 19, 2015
Priority date	Jun 30, 2014
Publication date	Aug 28, 2018
Grant date	Aug 28, 2018

Abstract

In one embodiment, a system includes at least one sensor configured to communicate a signal representative of blower vane position, wherein the blower vane is disposed in a blower of an exhaust gas recirculation system receiving exhaust from a gas turbine system and recycling the exhaust gas back to the gas turbine system. The system further includes a controller communicatively coupled to the at least one sensor, wherein the controller is configured to execute a control logic to derive a reference value for the blower vane position, and wherein the controller is configured to apply a direct limit, an model-based limit, or a combination thereof, to the reference value to derive a limit-based value, and wherein the controller is configured to position the blower vane based on the limit-based value.

First claim

The invention claimed is:

1. A system comprising:
a at least one sensor disposed in a blower and configured to communicate a first angle position of a blower vane, wherein the blower vane is disposed inside the blower of an exhaust gas recirculation system receiving an exhaust gas flow from a gas turbine system and recycling the exhaust gas back to the gas turbine system, wherein in operations of the blower the blower vane rotates to move the exhaust gas flow through the blower at pressures less than provided by compressor vanes of a compressor of the gas turbine system;
a controller communicatively coupled to the at least one sensor,
wherein the controller comprises programming configured to execute a control logic to:
compute, by executing a model-based control logic comprising a physics-based model, a model-based limit comprising a Mach number;
compare the Mach number to a Mach limit to derive an indirect limit comprising a difference between the Mach number and the Mach limit;
compute, by executing a proportional, integral, derivative (PID) control logic that comprises a gas turbine loading value as input, a vane position command;
compare the vane position command to a vane position limit to derive a PID limit comprising the difference between the vane position command and the vane position limit;
select the minimum of the indirect limit or the PID limit;
derive a second angle position of the blower vane by model-based control or by PID control via adjustment to the first angle position based on the minimum of the indirect limit or the PID limit; and
transmit an actuation signal to a blower vane actuator to position the blower vane to the second angle position.

2. The system of claim 1 , wherein the blower is configured to increase an inlet pressure to the gas turbine during operation based on the second angle position of the blower vane.

3. The system of claim 1 , wherein the PID control logic is configured to compute the vane position command by executing a schedule lookup that maps a plurality of gas turbine loading values to vane reference values.

4. The system of claim 1 , wherein the programming is configured to execute the control logic to derive a direct limit comprising an exhaust temperature limit value, a compressor discharge temperature limit value, or a combination thereof, by comparing a sensed exhaust temperature to a first temperature tolerated by a first component of the gas turbine receiving the exhaust gas flow, by comparing a sensed compressor discharge temperature to a second temperature tolerated by a second component of the gas turbine receiving a compressor discharge flow of the compressor.

5. The system of claim 1 , wherein the physics-based model comprises of thermodynamic operations of the gas turbine system.

6. The system of claim 1 , wherein the model-based control logic is configured to:
compute, a torque by executing a second physics-based model of the gas turbine;
compare the torque to a torque limit to derive a second indirect limit comprising a difference between the torque and the torque limit;
select the minimum of the indirect limit, the second indirect limit, or the PID limit;
derive a third angle position of the blower vane by model-based control or by PID control via adjustment to the first angle position based on the minimum of the indirect limit, the second indirect limit or the PID limit; and
transmit the actuation signal to the blower vane actuator to position the blower vane to the third angle position.

7. The system of claim 1 , comprising the exhaust gas recirculation system, wherein the exhaust gas recirculation system comprises a heat recovery steam generation (HRSG) system fluidly coupled to the blower, and to an exhaust gas recirculation cooler, wherein the HRSG is upstream of the blower, and the blower is upstream of the exhaust gas recirculation cooler.

8. The system of claim 1 , wherein the controller is configured to:
adjust the actuation signal to enable a combustion stoichiometry of the gas turbine system of approximately between 0.95 to 1.05.

9. A method, comprising:
sensing a first angle position of a blower vane of a blower, wherein the blower vane is disposed inside the blower and wherein in operations of the blower the blower vane rotates to move a gas turbine exhaust gas flow through the blower at pressures less than provided by compressor vanes of a compressor of a gas turbine system;
receiving a desired loading for the gas turbine system;
computing, via non-model based control logic comprising a physics-based model, a model-based limit comprising a Mach number;
comparing the Mach number to a Mach limit to derive an indirect limit comprising a difference between the Mach number and the Mach limit;
computing, by executing a proportional, integral, derivative (PID) control logic that comprises a gas turbine loading value as input, a vane position command;
comparing the vane position command to a vane position limit to derive a PID limit comprising the difference between the vane position command and the vane position limit;
selecting the minimum of the indirect limit or the PID limit;
deriving a second angle position of the blower vane by model-based control or by PID control via adjustment to the first angle position based on the minimum of the indirect limit or the PID limit; and
transmitting an actuation signal to a blower vane actuator to position the blower vane at the second angle position.

10. The method of claim 9 , wherein the PID control logic is configured to compute the vane position command by executing a schedule lookup that maps a plurality of gas turbine loading values to vane reference values.

11. The method of claim 9 , wherein physics-based model of the gas turbine system comprises a thermodynamic model.

12. The method of claim 9 , wherein the model-based control logic is configured to:
compute, by executing a second physics-based model of the gas turbine;
compare the torque to a torque limit to derive a second indirect limit comprising a difference between the torque and the torque limit;
select the minimum of the indirect limit, the second indirect limit, or the PID limit;
derive a third angle position of the blower vane by model-based control or by PID control via adjustment to the first angle position based on the minimum of the indirect limit, the second indirect limit or the PID limit; and
transmit the actuation signal to the blower vane actuator to position the blower vane to the third angle position.

13. The method of claim 9 , wherein the PID control logic comprises a proportional control logic, and integral control logic, a derivative control logic, or a combination thereof.

14. The method of claim 9 , comprising deriving a direct limit comprising an exhaust temperature limit value, a compressor discharge temperature limit value, or a combination thereof, by comparing a sensed exhaust temperature to a first temperature tolerated by a first component of the gas turbine receiving the exhaust gas flow, by comparing a sensed compressor discharge temperature to a second temperature tolerated by a second component of the gas turbine receiving a compressor discharge flow of the compressor.

15. The method of claim 9 , wherein the gas turbine system comprises a stoichiometric exhaust gas recirculation (SEGR) gas turbine engine configured to supply carbon dioxide to an enhanced oil recovery (EOR) system.

16. A control system comprising:
a processor configured to:
sense a first angle position of a blower vane of a blower, wherein the blower vane is disposed inside the blower and

Assignees

• Gen Electric
• Exxonmobil Upstream Res Co
• Exxxonmobil Upstream Res Company

Inventors

• Minto Karl Dean
• Denman Todd Franklin
• Mittricker Franklin F
• Huntington Richard Alan

Classifications

• F05D2270/703

  integral · CPC title

• F02C3/34 Primary

  with recycling of part of the working fluid, i.e. semi-closed cycles with combustion products in the closed part of the cycle · CPC title

• F05D2270/80

  Devices generating input signals, e.g. transducers, sensors, cameras or strain gauges · CPC title

• F05D2220/32

  in gas turbines · CPC title

• F02C1/08

  Semi-closed cycles · CPC title