COMBINED CYCLE PLANT, CONTROL DEVICE THEREOF, AND STEAM TURBINE STARTUP METHOD

• US 20200132032A1
• Filed: 12/31/2019
• Published: 04/30/2020
• Est. Priority Date: 07/12/2016
• Status: Active Grant

• Current Assignee: Mitsubishi Heavy Industries, Ltd.
• Original Assignee: mitsubishi hitachi power systems, ltd. (Mitsubishi Heavy Industries, Ltd.)
• Inventors: MATSUSHIRO, Goichi, HATANO, Ken
• Granted Patent: US 11,506,089 B2
• Time in Patent Office: Days
• CPC Class Codes: F01D 19/00 Starting of machines or engines; Regulating, controlling, or safety means in connection therewith warming-up before starting F01D25/10; turning or inching gear F01D25/34
• CPC Class Codes: F01K 13/02 Controlling, e.g. stopping or starting
• CPC Class Codes: F01K 17/025 in combination with at least one gas turbine, e.g. a combustion gas turbine
• CPC Class Codes: F01K 23/10 with exhaust fluid of one cycle heating the fluid in another cycle F01K17/025 takes precedence
• CPC Class Codes: F01K 23/101 Regulating means specially adapted therefor F01K23/105, F01K23/108 take precedence
• CPC Class Codes: F01K 23/103 with afterburner in exhaust boiler
• CPC Class Codes: F01K 23/105 Regulating means specially adapted therefor
• CPC Class Codes: F02C 6/18 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 Class Codes: F02C 9/56 with power transmission control
• CPC Class Codes: F05D 2260/85 Starting
• CPC Class Codes: Y02E 20/16 Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT]

Abstract

To provide a combined cycle plant, a control device thereof, and a steam turbine startup method that are aimed at improving the operability of a combined cycle plant by allowing a quick change of the output. A combined cycle plant is provided with: a gas turbine having a compressor, a combustor, and a turbine; a supplementary firing burner that raises the temperature of exhaust gas of the gas turbine; a heat recovery steam generator that generates steam using exhaust heat of the exhaust gas; a steam turbine that is driven by steam generated by the heat recovery steam generator; and a control device that changes both an output of the combustor and an output of the supplementary firing burner when an output of the combined cycle plant is to be changed.

Claims

1. A method of starting up a combined cycle plant, the combined cycle plant comprising:

a gas turbine having a compressor, a combustor, and a turbine;

a supplementary firing burner that raises a temperature of exhaust gas of the gas turbine;

a heat recovery steam generator that generates steam using exhaust heat of the exhaust gas; and

a steam turbine that is driven by steam generated by the heat recovery steam generator,

the method comprising;

changing both an output of the combustor and an output of the supplementary firing burner when an output of the combined cycle plant is to be changed; and

selecting a first output change mode at startup of the steam turbine, and switching to a second output change mode after completion of warming up of the steam turbine,

wherein in the first output change mode, the output of the combustor is changed and the output of the supplementary firing burner is held constant when the output of the combined cycle plant is to be changed,

in the second output change mode, both the output of the combustor and the output of the supplementary firing burner are changed when the output of the combined cycle plant is to be changed, and

the first output change mode and the second output change mode are capable of being selectively switched according to a first switching signal.

2. The method of starting up the combined cycle plant according to claim 1, comprising selecting the first output change mode at startup of the steam turbine, and switching to the second output change mode before an output of the steam turbine reaches a maximum output that is achievable with steam generated using only exhaust heat of exhaust gas of the gas turbine.

3. The method of starting up the combined cycle plant according to claim 1, wherein in a third output change mode, the output of the combustor is changed when the output of the combined cycle plant is to be changed, and after a preset predetermined output of the steam turbine is reached, the output of the supplementary firing burner is changed, and

the second output change mode and the third output change mode are capable of being selectively switched according to a second switching signal.

4. The method of starting up the combined cycle plant according to claim 3, wherein in a first operation mode, both the output of the combustor and the output of the supplementary firing burner are changed when the output of the combined cycle plant is to be changed at startup of the steam turbine, and after a target output of the combined cycle plant is reached, the output of the combustor is preferentially changed in response to a variation in the target output;

and

in a second operation mode, the output of the combustor is held constant and the output of the supplementary firing burner is changed in response to a variation in the target output.