METHOD FOR CONTROLLING THE OPERATION OF A GAS TURBINE WITH SEQUENTIAL COMBUSTION

• US 20160252017A1
• Filed: 01/26/2016
• Published: 09/01/2016
• Est. Priority Date: 02/26/2015
• Status: Abandoned Application

• Current Assignee: Ansaldo Energia IP UK Limited (Ansaldo Energia SPA)
• Original Assignee: Alstom Technology Ltd. (Alstom SA)
• Inventors: Schesny, Andreas Jan, Schiessel, Pimin, Siewert, Piotr, Lddecke, Torsten, Dhital, Rajeshwor
• Application Number:
  US15/006,480
• Publication Number:
  US 20160252017A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F01D 21/003 Arrangements for testing or measuring for measuring vibrations G01H
• CPC Class Codes: F02C 3/14 characterised by the arrangement of the combustion chamber in the plant combustion chambers per se F23R; F02C3/205 takes precedence
• CPC Class Codes: F02C 6/003 Gas-turbine plants with heaters between turbine stages
• CPC Class Codes: F02C 7/042 having variable geometry
• CPC Class Codes: F02C 7/057 Control or regulation conjointly with fuel supply control F02C9/50, with nozzle area control F02K1/16
• CPC Class Codes: F02C 9/22 by adjusting turbine vanes
• 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 9/54 by throttling the working fluid, by adjusting vanes
• CPC Class Codes: F05D 2220/32 in gas turbines
• CPC Class Codes: F05D 2240/35 Combustors or associated equipment
• CPC Class Codes: F05D 2250/52 Outlet
• CPC Class Codes: F05D 2270/303 Temperature
• CPC Class Codes: F05D 2270/309 Rate of change of parameters

Abstract

A method for controlling the operation of a gas turbine with sequential combustion, which gas turbine comprises a compressor with variable inlet guide vanes (VIGV), a first combustor, a high-pressure turbine downstream of the first combustor, a second combustor downstream of the high-pressure turbine, and a low-pressure turbine downstream of the second combustor.

Claims

1. A method for controlling the operation of a gas turbine with sequential combustion, which gas turbine comprises a compressor with variable inlet guide vanes (VIGV), a first combustor, a high-pressure turbine Downstream of said first combustor, a second combustor downstream of said high-pressure turbine, and a low-pressure turbine downstream of said second combustor, said method comprising the steps of:

verifying that the gas turbine operates under base load conditions;

continuously measuring locally at various points the turbine outlet temperature TAT1 of the high-pressure turbine;

averaging over the various local TAT1 measurement values to get an average TAT1 temperature (TAT1 AVG);

controlling the operation of the first combustor in dependence of said average TAT1 temperature (TAT1 AVG);

checking if at least one local TAT1 measurement value, which is higher than said average TAT1 temperature (TAT1 AVG), is increasing;

adjusting said average TAT1 temperature (TAT1 AVG), if said at least one local TAT1 measurement value is increasing above a predetermined threshold value.

2. The method as claimed in claim 1, wherein said base load conditions comprise said variable inlet guide vanes (VIGV) to be open, a turbine inlet temperature (TIT1) of said first combustor being at a base load value, and a turbine inlet temperature (TIT2) of said second combustor being at a base load value.

3. The method as claimed in claim 1, wherein the moving average of a plurality of local TAT1 measurement values, which are higher than said average TAT1 temperature (TAT1 AVG), is checked, and said average TAT1 temperature (TAT1 AVG) is adjusted, if said moving average is increasing above a predetermined threshold value.

4. The method as claimed in claim 3, wherein the largest local TAT1 measurement value of said moving average is neglected.

5. The method as claimed in claim 3, wherein said moving average is evaluated on a time scale of 10 minutes or longer.

6. The method as claimed in claim 5, wherein said moving average is evaluated on a time scale of 20 minutes.

7. The method as claimed in claim 1, wherein said predetermined threshold value is at least 5 K above a local TAT1 reference value.

8. The method as claimed in claim 7, wherein said predetermined threshold value is 10 K above a local TAT1 reference value.

9. The method as claimed in claim 1, wherein said adjusting of the average TAT1 temperature (TAT1 AVG) is done by stepwise decreasing said average TAT1 temperature (TAT1 AVG) by a predetermined amount.

10. The method as claimed in claim 3, wherein the NOx content of the exhaust gases of the gas turbine is measured by NOx CEMS measuring means, and that said average TAT1 temperature (TAT1 AVG) is only adjusted, if in addition the moving average of the NOx CEMS emission measurement values is above a predetermined threshold value.

11. The method as claimed in claim 10, wherein said moving average of the NOx CEMS emission measurement values is evaluated on a time scale of 20 minutes, and said threshold value is at 80% of guaranteed NOx emission level.

12. The method as claimed in claim 10, wherein pressure pulsations are measured in said first combustor, and that said average TAT1 temperature (TAT1 AVG) is only adjusted, if in addition the low frequency part of said measured pressure pulsations, especially in the frequency band between 100 Hz and 150 Hz, are below a predetermined threshold value, of especially 30 mbar.

13. The method as claimed in claim 12, wherein said average TAT1 temperature (TAT1 AVG) is only adjusted, if all said adjustment criteria are fulfilled for a predetermined number of separate base load cycles and a predetermined time of operation.

14. The method as claimed in claim 13, wherein said predetermined number of separate base load cycles is at least 5, and that said predetermined time of operation is at least 120 minutes.