Gas turbine and method for operating gas turbine

Patent metadata

Field	Value
Publication number	US-2019153963-A1
Application number	US-201716316263-A
Country	US
Kind code	A1
Filing date	May 12, 2017
Priority date	Jul 11, 2016
Publication date	May 23, 2019
Grant date	—

Abstract

A gas turbine equipped with: a low-pressure bleed passage, a medium-pressure bleed passage, and a high-pressure bleed-passage for supplying compressed air bled from respective bleed chambers to a turbine; a low-pressure exhaust passage, a medium-pressure exhaust passage, and a high-pressure exhaust passage for exhausting the compressed air in the respective bleed passages to an exhaust chamber; a low-pressure exhaust valve, a medium-pressure exhaust valve, and a high-pressure exhaust valve provided respectively in the exhaust passages; a low-pressure ejector and a medium-pressure ejector provided in the respective exhaust passages; a driving air supply passage for supplying the compressed air to the ejectors; and a control device that opens the exhaust valves and supplies compressed air from the driving air supply passage to the ejectors when the operating state of a gas turbine is in a region in which rotation stall is generated.

First claim

1 . A gas turbine which includes a compressor, a combustor, and a turbine, the gas turbine comprising:
a bleed passage for supplying compressed air bled from the compressor to the turbine as cooling air; an exhaust passage for exhausting the compressed air in the bleed passage to a turbine exhaust system; an exhaust valve which is provided in the exhaust passage; an ejector which is provided further on the downstream side in a flow direction of the compressed air than the exhaust valve in the exhaust passage; a driving fluid supply device which supplies a driving fluid to the ejector; and a control device which opens the exhaust valve and operates the driving fluid supply device, at the time of start-up or stopping of the gas turbine.

2 . The gas turbine according to claim 1 , wherein the control device opens the exhaust valve and operates the driving fluid supply device, when an operating state of the gas turbine is in a region where a rotating stall occurs.

3 . The gas turbine according to claim 1 , wherein the control device opens the exhaust valve and operates the driving fluid supply device, at the time of the start-up of the gas turbine, and closes the exhaust valve and stops an operation of the driving fluid supply device, if a start-up state of the gas turbine comes out of a region where a rotating stall occurs.

4 . The gas turbine according to claim 1 , wherein the control device closes the exhaust valve and stops an operation of the driving fluid supply device, if a rotational speed of the gas turbine becomes equal to or higher than a predetermined rotational speed at which a rotating stall does not occur.

5 . The gas turbine according to claim 1 , further comprising:
a pressure detector which detects a pressure of the compressed air flowing through the exhaust passage or a pressure of the driving fluid which is supplied to the ejector by the driving fluid supply device, wherein the control device controls an operation of the driving fluid supply device, based on a detection result of the pressure detector.

6 . The gas turbine according to claim 5 , wherein the driving fluid supply device includes a driving fluid supply passage for supplying the driving fluid to the ejector, and a flow regulation valve which is provided in the driving fluid supply passage, and
the control device controls a degree of opening of the flow regulation valve, based on the detection result of the pressure detector.

7 . The gas turbine according to claim 1 , wherein the driving fluid supply device supplies a driving fluid having a pressure higher than the pressure of the compressed air flowing through the exhaust passage to the ejector.

8 . The gas turbine according to claim 1 , wherein the driving fluid supply device supplies the compressed air which is supplied from the compressor to the combustor to the ejector.

9 . The gas turbine according to claim 1 , wherein a first bleed passage and a second bleed passage which each supply the compressed air bled from a first bleed chamber and a second bleed chamber further on the high-pressure side than the first bleed chamber of the compressor to the turbine as the cooling air are provided,
a first exhaust passage and a second exhaust passage which each exhaust the compressed air in the first bleed passage and the second bleed passage to the turbine exhaust system are provided, the ejector is provided in the first exhaust passage, and the driving fluid supply device supplies the compressed air flowing through the second exhaust passage to the ejector.

10 . The gas turbine according to claim 1 , wherein the driving fluid supply device supplies compressed air from a compressed air supply source which is provided outside to the ejector.

11 . The gas turbine according to claim 1 , wherein the driving fluid supply device includes a first driving fluid supply device which supplies compressed air from an external compressed air supply source which is provided outside the compressor and a casing of the combustor to the ejector, and a second driving fluid supply device which supplies compressed air from an internal compressed air supply source which is provided inside the compressor or the combustor to the ejector, and
the control device operates the first driving fluid supply device and stops the second driving fluid supply device, at the time of start-up, and stops the first driving fluid supply device and operates the second driving fluid supply device, if a rotational speed of the gas turbine reaches a predetermined rotational speed set in advance.

12 . The gas turbine according to claim 1 , wherein the exhaust valve is integrally provided in the ejector.

13 . The gas turbine according to claim 1 , further comprising:
a cooling air passage for supplying the cooling air to an upper portion of a casing of the combustor; an on-off valve which is provided in the cooling air passage; an ejector for cooling air which is provided in the cooling air passage; and a driving fluid supply device for cooling air which supplies a driving fluid to the ejector for cooling air, wherein the control device opens the on-off valve and operates the driving fluid supply device for cooling air, after the stopping of the gas turbine.

14 . A method for operating a gas turbine which includes a compressor, a combustor, and a turbine, the method comprising:
a step of starting the gas turbine; a step of supplying compressed air bled from the compressor to the turbine as cooling air; a step of operating the gas turbine at a rated rotational speed; a step of stopping the gas turbine; and a step of increasing a speed of some of the compressed air bled from the compressor by an ejector and exhausting the compressed air to a turbine exhaust system, at the time of start-up or stopping of the gas turbine.

15 . The method for operating a gas turbine according to claim 14 , further comprising:
a step of stopping exhaust of the compressed air bled from the compressor to the turbine exhaust system, if a rotational speed of the gas turbine becomes equal to or higher than a predetermined rotational speed at which a rotating stall does not occur.

Assignees

• Mitsubishi Hitachi Power Sys

Inventors

• Kitaguchi Yoshinori

Classifications

• F02C7/26

  Starting; Ignition · CPC title

• F02C9/28 Primary

  Regulating systems responsive to plant or ambient parameters, e.g. temperature, pressure, rotor speed (F02C9/30 - F02C9/38, F02C9/44 take precedence) · CPC title

• F02C9/18

  by bleeding, bypassing or acting on variable working fluid interconnections between turbines or compressors or their stages {(F02C3/113 takes precedence)} · CPC title

• F05D2260/601

  using an ejector or a jet pump · CPC title

• F02C6/08 Primary

  the gas being bled from the gas-turbine compressor · CPC title