Two-shaft gas turbine

Patent metadata

Field	Value
Publication number	US-10094290-B2
Application number	US-201514790603-A
Country	US
Kind code	B2
Filing date	Jul 2, 2015
Priority date	Jul 3, 2014
Publication date	Oct 9, 2018
Grant date	Oct 9, 2018

Abstract

A two-shaft gas turbine is provided which includes: a compressor; a combustor having multiple fuel systems and generating combustion gas by combusting fuels from the fuel systems and air compressed by the compressor; a high-pressure turbine coupled coaxially with the compressor and rotated by the combustion gas; a low-pressure turbine having a shaft structure independent of the high-pressure turbine and rotated by exhaust gas from the high-pressure turbine; an air extraction channel for extracting the air compressed by the compressor; an injection flow channel for feeding the air extracted through the air extraction channel back to the combustor; and a controller for controlling the flow rate of the fuel supplied to each of the fuel systems based on the air flow rate of the compressor, on the flow rate of the fuel supplied to the combustor, and on the temperature of the air in the injection flow channel.

First claim

What is claimed is:

1. A two-shaft gas turbine system comprising:
a compressor having an intake equipped with an inlet guide vane;
a combustor having a plurality of fuel systems configured to be supplied with fuel independently of one another and to generate combustion gas by combusting the fuel from the fuel systems and air compressed by the compressor;
a high-pressure turbine coupled coaxially with the compressor and rotated by the combustion gas from the combustor to drive the compressor;
a low-pressure turbine having a shaft structure independent of the high-pressure turbine and rotated by exhaust gas from the high-pressure turbine to drive a load;
an air extraction channel configured to extract the air compressed by the compressor;
external equipment configured to take the air through the air extraction channel, process the air in a predetermined manner, and discharge the processed air;
an injection flow channel for configured to feed the air discharged from the external equipment back to the combustor; and
a controller configured to control a flow rate of the fuel supplied to each of the fuel systems based on an air flow rate of the compressor, a flow rate of the fuel supplied to the combustor, and a temperature of the air in the injection flow channel,
wherein the controller, at a time of start-up of the gas turbine, is further configured to:
control a timing when the fuel is newly added among the fuel systems based on the air flow rate of the compressor, the flow rate of the fuel supplied to the combustor, and the temperature of the air in the injection flow channel, and
when the temperature of the air in the injection flow channel is lower than a predetermined value, increase the flow rate of the fuel supplied to each of the fuel systems currently supplied with the fuel among the fuel systems.

2. The two-shaft gas turbine system according to claim 1 , further comprising:
an angle sensor for the inlet guide vane;
a rotation speed indicator for the compressor or for the high-pressure turbine;
a flow sensor for the fuel to be supplied to the combustor; and
a temperature sensor for the air in the injection flow channel;
wherein the controller, at the time of start-up of the gas turbine, is further configured to control the flow rate of the fuel supplied to each of the fuel systems based on the air flow rate of the compressor calculated from the output of the angle sensor and from the output of the rotation speed indicator, the output of the flow sensor, and the output of the temperature sensor.

3. The two-shaft gas turbine system according to claim 1 , wherein the controller, at the time of start-up of the gas turbine, is further configured to:
calculate a combustion control demand based on the air flow rate of the compressor, the flow rate of the fuel supplied to the combustor, and the temperature of the air in the injection flow channel, and
control the timing when the fuel is added from among the fuel systems based on the combustion control demand, wherein the timing when the fuel is added from among the fuel systems is specified by a switchover threshold value which is a predetermined value of the combustion control demand, and
correct the combustion control demand such that the combustion control demand decreases as the temperature of the air in the injection flow channel decreases, when the temperature of the air in the injection flow channel is lower than the predetermined value.

4. The two-shaft gas turbine system according to claim 3 , wherein the controller is further configured to:
not correct the combustion control demand after the start-up of the gas turbine is completed.

5. The two-shaft gas turbine system according to claim 3 , wherein the controller, at the time of start-up of the gas turbine, is further configured to:
determine whether warm-up is completed or not based on the temperature of the air in the injection flow channel, and to not correct the combustion control demand after the warm-up is completed.

6. A control method for a two-shaft gas turbine system including a compressor compressing air, a combustor having a plurality of fuel systems configured to be supplied with fuel independently of one another and generating combustion gas by combusting the fuel from the fuel systems and the air compressed by the compressor, a high-pressure turbine coupled coaxially with the compressor and rotated by the combustion gas from the combustor to drive the compressor, and a low-pressure turbine having a shaft structure independent of the high-pressure turbine and rotated by exhaust gas from the high-pressure turbine to drive a load, the control method comprising:
extracting the air compressed by the compressor;
introducing the extracted air to external equipment, processing the extracted air in a predetermined manner, and discharging the processed air;
feeding the air discharged from the external equipment to the combustor;
controlling, at a time of start-up of the gas turbine, a timing when the fuel is added from among the fuel systems based on the air flow rate of the compressor, the flow rate of the fuel supplied to the combustor, and the temperature of the air discharged from the external equipment; and
when the temperature of the air discharged from the external equipment is lower than a predetermined value, increasing, at the time of start-up of the gas turbine, the flow rate of the fuel supplied to each fuel system currently supplied with the fuel in the fuel systems.

Assignees

• Mitsubishi Hitachi Power Sys

Inventors

• Koganezawa Tomomi
• Abe Kazuki

Classifications

• F05D2270/303

  Temperature · CPC title

• F05D2270/313

  Air temperature · 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

• F02C3/10 Primary

  with another turbine driving an output shaft but not driving the compressor · CPC title

• F02C7/22 Primary

  Fuel supply systems · CPC title