Systems and methods to improve shut-down purge flow in a gas turbine system

Patent metadata

Field	Value
Publication number	US-10082087-B2
Application number	US-201615247129-A
Country	US
Kind code	B2
Filing date	Aug 25, 2016
Priority date	Aug 25, 2016
Publication date	Sep 25, 2018
Grant date	Sep 25, 2018

Abstract

A system includes a controller including a memory storing instructions and a processor that executes the instructions. The instructions cause the controller to receive a first input signal of a first temperature at an inlet of a gas turbine of a gas turbine and heat recovery steam generator (HRSG) system and a second input signal of a rotational speed of the gas turbine. The instructions also cause the controller to calculate the exhaust flow rate of the gas turbine and HRSG system based on the first input signal and the second input signal. Further, the instructions cause the controller to control the gas turbine and HRSG system to isolate a fuel source at a portion of normal operating speed of the gas turbine sufficient to achieve a predetermined purging volume during coast down of air flow through the gas turbine and HRSG system based on the exhaust flow rate.

First claim

The invention claimed is:

1. A system, comprising:
a controller of a gas turbine and heat recovery steam generator (HRSG) system, comprising:
a memory storing instructions to perform operations of the gas turbine and HRSG system; and
a processor configured to execute the instructions, wherein the instructions, when executed by the processor, cause the controller to:
receive a first input signal representative of a first temperature at an inlet of a compressor section of a gas turbine of the gas turbine and HRSG system and a second input signal representative of a rotational speed of the gas turbine;
calculate an exhaust flow rate of the gas turbine and HRSG system based on at least the first input signal and the second input signal; and
control the gas turbine and HRSG system, during shut-down of the gas turbine and HRSG system, to isolate a fuel source from the gas turbine at a portion of normal operating speed of the gas turbine sufficient to achieve a predetermined purging volume during coast down of air flow through the gas turbine and HRSG system based on the exhaust flow rate.

2. The system of claim 1 , wherein the instructions, when executed by the processor, cause the controller to receive a third input signal representative of a second temperature at an exhaust flow path of the gas turbine and HRSG system.

3. The system of claim 2 , comprising:
a first temperature sensor that provides the first input signal, wherein the first temperature sensor is positioned at the inlet of the compressor section of the gas turbine;
a rotational speed sensor that provides the second input signal; and
a second temperature sensor that provides the third input signal, wherein the second temperature sensor is positioned along an exhaust of the gas turbine or an exhaust stack of an HRSG of the gas turbine and HRSG system.

4. The system of claim 2 , wherein the exhaust flow rate is calculated based on at least the third input signal in addition to the first input signal and the second input signal.

5. The system of claim 1 , wherein the predetermined purging volume is based on at least a volume of the HRSG.

6. The system of claim 1 , wherein the instructions, when executed by the processor, cause the controller to control the gas turbine and HRSG system to isolate the fuel source when the gas turbine reaches the portion of normal operating speed of the gas turbine sufficient to achieve the purging volume while the gas turbine operates at a rotational speed greater than a minimum purge flow requirement of the gas turbine.

7. The system of claim 1 , wherein the instructions, when executed by the processor, cause the controller to maintain the gas turbine at or above a minimum purge flow speed until the purge volume is achieved.

8. A method, comprising:
utilizing a controller to:
receive a first measurement of a first temperature of a gas turbine and heat recovery steam generator (HRSG) system from a first sensor, wherein the measurement of the first temperature comprises at least a temperature at an inlet of a gas turbine of the gas turbine and HRSG system;
receive a second measurement of a rotational speed of the gas turbine from a second sensor;
calculate an exhaust volume flow rate of the gas turbine and HRSG system based on at least the first temperature and the rotational speed of the gas turbine;
obtain a purging volume of the gas turbine and HRSG system that is based on at least a volume of an HRSG of the gas turbine and HRSG system; and
control the gas turbine and HRSG system, during shut-down of the gas turbine and HRSG system, to isolate a fuel source from the gas turbine at a portion of normal operating speed of the gas turbine of the gas turbine and HRSG system sufficient to achieve the purging volume during coast down of air flow through the gas turbine and HRSG system based on the exhaust volume flow rate.

9. The method of claim 8 , wherein the first sensor comprises a temperature sensor positioned at an inlet of a compressor section of the gas turbine, and the second sensor comprises a rotational speed sensor of the gas turbine.

10. The method of claim 8 , comprising utilizing the controller to receive a third measurement of a second temperature of the gas turbine and HRSG system from a third sensor, wherein the third sensor comprises a temperature sensor positioned at an exhaust of the gas turbine or an exhaust stack of the HRSG, and calculating the exhaust volume flow rate of the gas turbine and HRSG system is based on at least the third parameter.

11. The method of claim 8 , wherein the second sensor comprises a rotational speed sensor of the gas turbine.

12. The method of claim 8 , wherein controlling the gas turbine and HRSG system to isolate the fuel source at a portion of normal operating speed of the gas turbine is based at least in part on a deceleration rate of a rotational speed of the gas turbine after the fuel source is isolated.

13. The method of claim 8 , wherein instructing the gas turbine and HRSG system to isolate the fuel occurs when the gas turbine reaches the portion of normal operating speed of the gas turbine sufficient to achieve the purging volume while the gas turbine operates at a rotational speed greater than a minimum purging speed of the gas turbine.

14. A tangible, non-transitory, machine-readable-medium, comprising machine-readable instructions to:
receive a first measurement of a first temperature of a power generation system from a first sensor;
receive a second measurement of a rotational speed of a gas turbine of the power generation system from a second sensor;
calculate an exhaust flow rate of the power generation system based on at least the first temperature and the rotational speed of the gas turbine; and
control the power generation system, during shut-down of the power generation system, to isolate a fuel source from the gas turbine at a portion of normal operating speed of the power generation system sufficient to achieve a purging volume during coast down of air flow through the power generation system based on at least the exhaust flow rate.

15. The machine-readable-medium of claim 14 , wherein the purging volume is based on at least a volume of a defined portion of the power generation system that comprises a heat recovery steam generator.

16. The machine-readable-medium of claim 14 , wherein the power generation system comprises a gas turbine and a heat recovery steam generator.

17. The machine-readable-medium of claim 14 , wherein the first sensor comprises a first temperature sensor positioned at an inlet of a compressor section of a gas turbine of the power generation system.

18. The machine-readable-medium of claim 14 , wherein the second sensor comprises a rotational speed sensor configured to measure a rotational speed of a gas turbine of the power generation system.

19. The machine-readable-medium of claim 14 , wherein the purging volume is achieved while the power generation system remains at a speed greater than a minimum purging speed of the power generation system.

20. The machine-readable-medium of claim 14 , comprising machine-readable instructions to:
receive a third measurement of a second temperature of the power generation system from a third sensor, wherein the third sensor comprises a second temperature sensor positioned at an exhaust of a gas turbine of the power generation system or an exhaust stack of a heat recovery steam generator of the power generation system, and wherein calculating the exhaust flow rate of the power generation

Assignees

• Gen Electric

Inventors

• Alexander Michael Joseph
• Davis Jr Lewis Berkley
• Snider David August

Classifications

• F01K13/003

  Arrangements for measuring or testing (in general G01) · CPC title

• F02C6/18

  using the waste heat of gas-turbine plants outside the plants themselves, e.g. gas-turbine power heat plants (using waste heat as source of energy for refrigeration plants F25B27/02; using the waste heat of a gasturbine for steam generation or in a steam cycle see F01K23/10) · CPC title

• F01D21/003

  Arrangements for testing or measuring (for measuring vibrations G01H) · CPC title

• F22B35/00

  Control systems for steam boilers (for regulating feed-water supply F22D5/00; for controlling superheat temperature F22G5/00) · CPC title

• F05D2220/32

  in gas turbines · CPC title