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

Patent metadata

Field	Value
Publication number	US-10082091-B2
Application number	US-201615247153-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 of a power generation system including a memory storing instructions and a processor that executes the instructions. The instructions cause the controller to control the power generation system to provide inlet bleed heat flow to a gas turbine during deceleration of the gas turbine. The instructions also cause the controller to receive a first temperature, a rotational speed of the gas turbine, and an inlet bleed heat flow rate. Additionally, the instructions cause the controller to calculate an exhaust flow rate based on at least the first temperature, the rotational speed, and the inlet bleed heat flow rate. Further, the instructions cause the controller to control the power generation 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 purging volume during coast down of the gas turbine.

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:
control the gas turbine and HRSG system to provide inlet bleed heat flow from an inlet bleed heating system to an exhaust plenum of a gas turbine of the gas turbine and HRSG system during deceleration of the gas turbine;
receive a first input signal representative of a first temperature at an inlet of a compressor section of the gas turbine, a second input signal representative of a rotational speed of the gas turbine, and a third input signal representative of an inlet bleed heat flow rate provided to the exhaust plenum of the gas turbine during deceleration of the gas turbine;
calculate an exhaust flow rate of the gas turbine and HRSG system based on at least the first input signal, the second input signal, and the third 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 , comprising:
a first temperature sensor that provides the first input signal;
a rotational speed sensor that provides the second input signal; and
a fluid flow sensor that provides the third input signal.

3. The system of claim 2 , wherein the first temperature sensor is positioned at the inlet of the compressor section, and the fluid flow sensor is positioned in a fluid flow line that couples the inlet bleed heating system to the exhaust plenum.

4. The system of claim 1 , wherein the instructions, when executed, cause the controller to receive at least a fourth input signal representative of a second temperature at the exhaust plenum of the gas turbine or an exhaust stack of an HRSG of the gas turbine and HRSG system, and the exhaust flow rate is based at least in part on the fourth input signal in addition to the first input signal, the second input signal, and the third input signal.

5. The system of claim 4 , comprising a second temperature sensor that provides the fourth input signal, wherein the second temperature sensor is positioned at the exhaust plenum of the gas turbine or the exhaust stack of the HRSG.

6. The system of claim 1 , wherein the predetermined purging volume is based on at least a volume of an HRSG of the gas turbine and HRSG system.

7. The system of claim 1 , wherein the instructions, when executed, cause the controller to control the gas turbine and HRSG system to isolate the fuel source from the gas turbine when the inlet bleed heat flow is provided to the exhaust plenum of the gas turbine, and 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.

8. The system of claim 1 , wherein the inlet bleed heat flow travels along an inlet bleed heat line, and the inlet bleed heat line comprises a first inlet bleed heat valve configured to couple the inlet bleed heat flow to the inlet of the compressor section and a second inlet bleed heat valve configured to couple the inlet bleed heat flow to the exhaust plenum of the gas turbine.

9. The system of claim 8 , wherein the controller is configured to close the first inlet bleed heat valve and open the second inlet bleed heat valve upon receiving a shut-down notification of the gas turbine and HRSG system.

10. A method, comprising:
utilizing a controller to:
control an inlet bleed heating system to provide an inlet bleed heat flow to an exhaust of a gas turbine of a heat recovery steam generator (HRSG) system;
receive a first measurement of a first temperature of the gas turbine and 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;
receive a third measurement of an inlet bleed heat flow rate from the inlet bleed heating system to the exhaust of the gas turbine and HRSG system during deceleration of the gas turbine from a third sensor;
calculate an exhaust volume flow rate of the gas turbine and HRSG system based on at least the first temperature, the rotational speed of the gas turbine, and the inlet bleed heat flow rate;
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 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.

11. The method of claim 10 , 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.

12. The method of claim 10 , comprising utilizing the controller to receive a fourth measurement of a second temperature of the gas turbine and HRSG system via a fourth sensor, wherein the fourth 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 of the gas turbine and HRSG system is based on at least the second temperature.

13. The method of claim 10 , comprising utilizing the controller to determine the portion of normal operating speed at which the fuel source is isolated from the gas turbine based at least in part on historical data relating to an amount of time the gas turbine takes to reach a minimum purging speed after isolating the fuel source from the gas turbine.

14. The method of claim 10 , wherein controlling the gas turbine and HRSG system to isolate the fuel source from the gas turbine at a portion of the normal operating speed of the gas turbine is based at least in part on a deceleration rate of the rotational speed of the gas turbine after the inlet bleed heat flow is provided to the exhaust of the gas turbine and the fuel source is isolated from the gas turbine.

15. A tangible, non-transitory, machine-readable-medium, comprising machine-readable instructions to:
receive a measurement of a first temperature of a power generation system via a first sensor, wherein the measurement of the first temperature comprises at least a temperature at an inlet of a gas turbine of the power generation system;
receive a measurement of a rotational speed of the gas turbine of the power generation system via a second sensor;
receive a measurement of an inlet bleed heat flow rate from an inlet bleed heating system to an exhaust of the power generation system during a shut-down mode of the power generation system via a third sensor;
calculate exhaust flow rate of the power generation system based on at least the first temperature, the rotational speed of the gas turbine, and the inlet bleed heat flow rate; and
control the power generation

Assignees

• Gen Electric

Inventors

• Snider David August
• Davis Lewis Berkley
• Rosson Randy Scott
• Alexander Michael Joseph

Classifications

• F05D2220/72

  a steam turbine · 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

• F05D2270/54

  by electronic means, e.g. electronic tubes, transistors or IC's within an electronic circuit · CPC title

• F01D25/10

  Heating, e.g. warming-up before starting · CPC title