Automated extended turndown of a gas turbine engine combined with incremental tuning to maintain emissions and dynamics

• US 9,890,714 B2
• Filed: 01/30/2015
• Issued: 02/13/2018
• Est. Priority Date: 05/26/2009
• Status: Active Grant

• Current Assignee: H2 IP UK Limited
• Original Assignee: Ansaldo Energia IP UK Limited (Ansaldo Energia SPA)
• Inventors: Soni, Sumit, Demougeot, Nicolas Roger, Stuttaford, Peter John
• Primary Examiner(s): Bui Pho, Pascal M
• Assistant Examiner(s): Thomas, Kyle
• Application Number:
  US14/610,760
• Publication Number:
  US 20150159563A1
• Time in Patent Office: 1,110 Days
• CPC Class Codes: F02C 7/228 Dividing fuel between various burners
• CPC Class Codes: F02C 9/28 Regulating systems responsive to plant or ambient parameters, e.g. temperature, pressure, rotor speed F02C9/30 - F02C9/38, F02C9/44 take precedence
• CPC Class Codes: F02C 9/34 Joint control of separate flows to main and auxiliary burners
• CPC Class Codes: F05D 2260/80 Diagnostics
• CPC Class Codes: F05D 2270/05 to affect the output of the engine
• CPC Class Codes: F05D 2270/082 with as little NOx as possible
• CPC Class Codes: F05D 2270/301 Pressure
• CPC Class Codes: F05D 2270/31 Fuel schedule for stage combustors
• CPC Class Codes: F23N 2241/20 Gas turbines
• CPC Class Codes: F23R 2900/00013 Reducing thermo-acoustic vibrations by active means
• CPC Class Codes: F23R 3/343 Pilot flames, i.e. fuel nozzles or injectors using only a very small proportion of the total fuel to insure continuous combustion ignition in gas-turbine plants F02C7/264; pilot flame igniters F23Q9/00
• CPC Class Codes: F23R 3/346 for staged combustion

Abstract

An auto-tune controller and tuning process implemented thereby for measuring and tuning the combustion dynamics and emissions of a GT engine, relative to predetermined upper limits, are provided. Initially, the tuning process includes monitoring the combustion dynamics of a plurality of combustors and emissions for a plurality of conditions. Upon determination that one or more of the conditions exceeds a predetermined upper limit, a fuel flow split to a fuel circuit on all of the combustors on the engine is adjusted by a predetermined amount. The control system continues to monitor the combustion dynamics and to recursively adjust the fuel flow split by the predetermined amount until the combustion dynamics and/or emissions are operating within a prescribed range of the GT engine. Additionally, a method of automated extended turndown of a GT engine to find a minimum load is provided.

Claims

1. A computerized method, implemented by a processing unit, for automated extended turndown of a combustor of a gas turbine (GT) engine, the method comprising:

receiving an input to perform the automated extended turndown on the GT engine;

monitoring one or more turndown criteria of the GT engine to determine if all of the one or more turndown criteria are met;

upon determining that all of the one or more turndown criteria are met, temporarily reducing a transfer-out turbine reference temperature (TTRF) if a difference between a current TTRF and the transfer-out TTRF of the GT engine is less than a configured amount;

sending a signal to reduce a load on the GT engine by a specified amount;

reducing the load on the GT engine by the specified amount based on the signal;

during and after the load has been reduced, monitoring the one or more turndown criteria to determine if any of the one or more turndown criteria are not met;

upon determining that at least one of the one or more turndown criteria is not met after the load has been reduced, tuning the load a selected number of times until the at least one turndown criteria is not met the selected number of times; and

upon the at least one turndown criteria not being met the selected number of times, storing a minimum load turndown TTRF where all turndown criteria have been met for a selected compressor inlet temperature (CTIM).

2. The method of claim 1, wherein upon determining if any of the one or more turndown criteria are met, again reducing the load by the specified amount or a modified specified amount.

3. The method of claim 1, wherein the selected CTIM comprises one or more CTIM ranges.

4. The method of claim 1, further comprising calculating the transfer-out TTRF, the transfer-out TTRF calculated by adding a first selected temperature margin to the minimum load turndown TTRF.

5. The method of claim 4, wherein the first selected temperature margin is selected based on a safety margin.

6. The method of claim 4, further comprising calculating an operating TTRF, the operating TTRF calculated by adding a second selected temperature margin to the minimum load turndown TTRF.

7. The method of claim 6, wherein the second selected temperature margin is greater than the first selected temperature margin.

8. The method of claim 1, wherein the processing unit is configured to transmit the minimum load turndown TTRF.

9. The method of claim 6, wherein the processing unit is configured to check restriction of tuning knobs to a user configured setting.

10. The method of claim 1, wherein the selected number of times comprises the exhaustion of a tuning margin.

11. The method of claim 6, wherein the processing unit is configured to generate an alarm to recheck the minimum load turndown TTRF when the CTIM changes from a first CTIM range to a second CTIM range.

12. The method of claim 1, wherein the turndown criteria comprise at least one of:

a nitrogen-oxide (NOx) level;

a combustor dynamics mode;

an average carbon monoxide (CO) level;

or fuel circuit splits.

13. A system for automated extended turndown, the system comprising:

a gas turbine (GT) engine including one or more combustors that are each provided with a first minimum turbine reference temperature (TTRF), a first transfer-out TTRF, and a first operating TTRF;

an auto-tuning controller for carrying out an automated extended turndown process comprising;

(a) receiving an input to the perform the automated extended turndown process;

(b) monitoring one or more turndown criteria to determine if the one or more turndown criteria are all met;

(c) upon determining that the one or more turndown criteria are all met, temporarily reducing the first transfer-out TTRF to a second transfer-out TTRF if a difference between a current TTRF and the first transfer-out TTRF is less than a configured amount;

(d) sending a signal to reduce a load on the GT engine by a specified amount;

(e) reducing the load on the GT engine by the specified amount based on the signal;

(f) during and after the load has been reduced, monitoring the one or more turndown criteria to determine if the any of the one or more turndown criteria is not met;

(g) upon determining that any of the one or more turndown criteria is not met during or after the load has been reduced, tuning the load a selected number of times until the turndown criteria that is not met is not met the selected number of times; and

(h) upon the turndown criteria that is not met being not met the selected number of times, storing a second minimum TTRF where all turndown criteria are met for a selected CTIM.

14. The system of claim 13, wherein the system further comprises a user input device.

15. The system of claim 14, wherein the system further comprises a user display device configured to receive and display information related to the monitored criteria.

16. The system of claim 13, further comprising a load controller configured to receive commands from the auto-tune controller to increase or decrease a load on the GT engine.

17. The system of claim 13, further comprising calculating a new transfer-out TTRF by adding a first selected temperature margin to the second minimum TTRF.

18. The system of claim 17, further comprising calculating a new operating TTRF by adding a second selected temperature margin to the second minimum TTRF.

19. The system of claim 13, further comprising:

checking turndown criteria to determine if a tuning limit is reached; and

determining a new higher minimum TTRF.

20. The system of claim 13, wherein the turndown criteria comprise at least one of:

a nitrogen-oxide (NOx) level;

a combustor dynamics mode;

an average carbon monoxide (CO) level;

or fuel circuit splits.

21. One or more non-transitory computer readable media that, when invoked by computer executable instructions, perform a method for automated extended turndown of a gas turbine (GT) engine, the method comprising:

monitoring one or more turndown criteria of the GT engine to determine if all of the one or more turndown criteria are met;

upon determining that all of the one or more turndown criteria are met, temporarily reducing a transfer-out turbine reference temperature (TTRF) if a difference between a current TTRF and the transfer-out TTRF is less than a configured amount;

sending a signal to reduce a load on the GT engine by a specified amount;

reducing the load on the GT engine by the specified amount based on the signal;

during and after the load has been reduced, monitoring the one or more turndown criteria to determine if any of the one or more turndown criteria is not met;

upon determining that at least one of the one or more turndown criteria is not met after the load has been reduced, tuning the load a selected number of times until the at least one turndown criteria that is not met is not met the selected number of times; and

upon the at least one turndown criteria that is not met being not met the selected number of times, storing a minimum load turndown TTRF where all of the one or more turndown criteria are met for a selected compressor inlet temperature (CTIM).