Systems and methods for optimizing stoichiometric combustion

Patent metadata

Field	Value
Publication number	US-9903279-B2
Application number	US-201113805646-A
Country	US
Kind code	B2
Filing date	Jun 27, 2011
Priority date	Aug 6, 2010
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

Provided are more efficient techniques for operating gas turbine systems. In one embodiment a gas turbine system comprises an oxidant system, a fuel system, a control system, and a number of combustors adapted to receive and combust an oxidant from the oxidant system and a fuel from the fuel system to produce an exhaust gas. The gas turbine system also includes a number of oxidant-flow adjustment devices, each of which are operatively associated with one of the combustors, wherein an oxidant-flow adjustment device is configured to independently regulate an oxidant flow rate into the associated combustor. An exhaust sensor is in communication with the control system. The exhaust sensor is adapted to measure at least one parameter of the exhaust gas, and the control system is configured to independently adjust each of the oxidant-flow adjustment devices based, at least in part, on the parameter measured by the exhaust sensor.

First claim

What is claimed is:

1. A gas turbine system, comprising:
an oxidant system;
a fuel system;
a control system;
a plurality of combustors adapted to receive and combust an oxidant from the oxidant system and a fuel from the fuel system to produce a plurality of exhaust gases;
a plurality of oxidant-flow adjustment devices, wherein each of the plurality of oxidant-flow adjustment devices is operatively associated with one of the plurality of combustors, wherein at least one of the oxidant-flow adjustment devices is configured to independently regulate an oxidant flow rate into an associated combustor to achieve substantially stoichiometric combustion; and
a plurality of exhaust sensors in communication with the control system, wherein the exhaust sensors are adapted to measure an oxygen concentration and a carbon monoxide concentration in each of the plurality of exhaust gases, and wherein the control system is configured to independently adjust at least one of the plurality of oxidant-flow adjustment devices based, at least in part, on the oxygen concentrations and carbon monoxide concentrations measured by the plurality of exhaust sensors to maintain a combined oxygen and carbon monoxide concentration of the plurality of exhaust gases within a predetermined range.

2. The system of claim 1 , wherein the oxidant comprises oxygen and a diluent.

3. The system of claim 1 , further comprising a diluent supply provided to each of the plurality of combustors.

4. The system of claim 1 , further comprising an oxidant compressor adapted to provide compressed oxidant to each of the plurality of combustors.

5. The system of claim 1 , wherein the oxidant-flow adjustment device comprises a flow control valve.

6. The system of claim 1 , wherein the oxidant-flow adjustment device comprises an adjustable swirler sub assembly.

7. The system of claim 6 , wherein the adjustable swirler sub assembly comprises an annular control assembly positioned around a flow sleeve to controllably regulate oxidant flow rates into the flow sleeve.

8. The system of claim 7 , wherein the annular control assembly comprises a plurality of articulating vanes operatively associated with a mounting ring and an actuator vane.

9. The system of claim 8 , wherein the plurality of vanes are adapted to be controllably adjusted between an open position and a closed position and positions therebetween by moving the actuator vane relative to the mounting vane.

10. The system of claim 1 , wherein the plurality of exhaust sensors and the control system are adapted to regulate oxidant flow rates to the plurality of combustors so as to minimize differences between measured parameters at different exhaust sensors.

11. The system of claim 1 , wherein the oxidant-flow adjustment device on at least one of the plurality of combustors is adapted to increase mixing of the oxidant, the fuel, a diluent, or any combinations thereof.

12. The system of claim 1 , wherein a combustor comprises a diluent inlet and an oxidant inlet, wherein the oxidant-flow adjustment device is disposed in the oxidant inlet, and wherein the oxidant-flow adjustment device is configured to mix the oxidant and the diluent before the fuel is introduced.

13. The system of claim 1 , further comprising a turbine expander adapted to receive the exhaust gas and to generate power.

14. The system of claim 13 , further comprising a heat recovery steam generator adapted to receive the exhaust gas from the turbine expander and to generate power.

15. The system of claim 13 , further comprising a diluent compressor and an exhaust gas recirculation loop adapted to receive the exhaust gas from the expander, wherein the exhaust gas recirculation loop comprises a heat recovery steam generator adapted to generate power, and a cooled exhaust line adapted to provide cooled exhaust gas to the diluent compressor, and wherein the diluent compressor is adapted to provide compressed diluent to the combustor.

16. The system of claim 15 , further comprising an exhaust gas extraction system disposed between the diluent compressor and the combustor, wherein the exhaust gas extraction system is adapted to extract diluent at elevated pressures.

17. The gas turbine system of claim 1 , wherein the predetermined range is between about 0.1 mol % and about 3 mol % combined oxygen and carbon monoxide concentration.

18. A method of controlling a gas turbine, the method comprising:
providing a fuel to a plurality of combustors on a gas turbine;
providing an oxidant to the plurality of combustors, wherein an oxidant flow rate is independently adjusted for each of the plurality of combustors;
substantially stoichiometrically combusting the fuel and the oxidant in each of the plurality of combustors to produce a plurality of exhaust gases;
measuring an oxygen concentration and a carbon monoxide concentration in each of the plurality of exhaust gases; and
adjusting the oxidant flow rate into each of the plurality of combustors based on the measured oxygen concentrations and carbon monoxide concentrations to maintain a combined oxygen and carbon monoxide concentration of the plurality of exhaust gases within a predetermined range.

19. The method of claim 18 , further comprising compressing the oxidant before the oxidant is provided to each of the plurality of combustors.

20. The method of claim 18 , further comprising returning a portion of the exhaust gas to the plurality of combustors as a diluent.

21. The method of claim 20 , further comprising compressing the diluent with a compressor before the diluent enters the combustor.

22. The method of claim 21 , wherein the compressor is operatively coupled to an expander adapted to receive the exhaust gas and to generate power therefrom.

23. The method of claim 22 , further comprising extracting at least a portion of the exhaust gas from a coupling disposed between the compressor and each of the plurality of combustors, wherein the amount of exhaust gas extracted is based, at least in part, on the parameter.

24. The method of claim 18 , wherein the predetermined range is between about 0.1 mol % and about 3 mol % combined oxygen and carbon monoxide concentration.

25. A non-transitory computer readable medium comprising code configured to direct a processor to:
provide a fuel to a plurality of combustors on a gas turbine;
provide an oxidant to the plurality of combustors, wherein an oxidant flow rate is independently adjusted for each of the plurality of combustors;
monitor an oxygen concentration and a carbon monoxide concentration in each of a plurality of exhaust gases produced in a flame in each of the plurality of combustors; and
adjust the oxidant flow rate into each of the plurality of combustors based on the measured oxygen concentrations and carbon monoxide concentrations to maintain a combined oxygen and carbon monoxide concentration of the plurality of exhaust gases within a predetermined range to achieve substantially stoichiometric combustion.

26. The non-transitory computer readable medium of claim 25 , comprising a data structure representing a swirl chart.

27. The non-transitory computer readable medium of claim 26 , comprising code configured to direct the processor to compare measurements associated with a plurality of sensors to the data structure to determine which of the plurality of combustors to adjust.

28. The non-tra

Assignees

• Mittricker Franklin F
• Huntington Richard A
• Exxonmobil Upstream Res Co

Inventors

• Mittricker Franklin F
• Huntington Richard A

Classifications

• F02C9/50

  with control of working fluid flow · CPC title

• F05D2270/08

  to produce clean exhaust gases · CPC title

• F02C3/22

  the fuel or oxidant being gaseous at standard temperature and pressure (F02C3/28 takes precedence) · CPC title

• F02C9/00 Primary

  Controlling gas-turbine plants; Controlling fuel supply in air- breathing jet-propulsion plants (controlling air intakes F02C7/057; controlling turbines F01D; controlling compressors F04D27/00; controlling in general G05) · CPC title

• F02C9/20 Primary

  by throttling; by adjusting vanes · CPC title