Gas turbine cogeneration system and operation mode change method therefor

Patent metadata

Field	Value
Publication number	US-11156130-B2
Application number	US-201916243766-A
Country	US
Kind code	B2
Filing date	Jan 9, 2019
Priority date	Jan 12, 2018
Publication date	Oct 26, 2021
Grant date	Oct 26, 2021

Abstract

Reduction of operation efficiency of a GTCS at a time of changing an operation using bypass stack to an operation using HRSG is suppressed. An HRSG of the GTCS is provided with an air supply piping and a ventilation piping connected to a fuel line of a duct burner at a position upstream of a main shut-off valve and downstream of a fuel shut-off valve, an air supply shut-off valve that opens/closes the air supply piping, and a ventilation shut-off valve that opens/closes the ventilation piping, and is configured such that during an operation using a bypass stack, an inlet of the HRSG is closed to open a bypass stack, a main shut-off valve and the fuel shut-off valve are closed, and the air supply shut-off valve and the ventilation shut-off valve are always opened, and at a time of changing to an operation using HRSG, the inlet of the HRSG is opened to close the bypass stack without shutting down a GT, the main shut-off valve and the fuel shut-off valve are opened, and the air supply shut-off valve and the ventilation shut-off valve are closed.

First claim

What is claimed is:

1. A gas turbine cogeneration system comprising:
a gas turbine; a heat recovery steam generator, a bypass stack provided upstream of the heat recovery steam generator in a gas turbine exhaust gas path; a bypass damper that opens/closes the bypass stack; and a computer that controls the gas turbine, the heat recovery steam generator, and the bypass damper, wherein
the heat recovery steam generator includes:
a duct burner;
a main shut-off valve that is provided in a fuel line of the duct burner;
a fuel shut-off valve that is provided upstream of the main shut-off valve in the fuel line of the duct burner;
an air supply piping that joins the fuel line at a position upstream of the main shut-off valve and downstream of the fuel shut-off valve;
an air supply shut-off valve that is provided in the air supply piping;
a ventilation piping that is branched off from the fuel line at a position upstream of the main shut-off valve and downstream of the fuel shut-off valve; and
a ventilation shut-off valve that is provided in the ventilation piping, and
the computer is programed,
during an operation using the bypass stack, to close an inlet of the heat recovery steam generator to open the bypass stack, close the main shut-off valve and the fuel shut-off valve, and open the air supply shut-off valve and the ventilation shut-off valve, thereby always executing a purge of the fuel line by opening the air supply piping and the ventilation piping, and
at a time of changing to an operation using the heat recovery steam generator, to open the inlet of the heat recovery steam generator to close the bypass stack without shut down of the gas turbine, open the main shut-off valve and the fuel shut-off valve, and close the air supply shut-off valve and the ventilation shut-off valve.

2. The gas turbine cogeneration system according to claim 1 , wherein
the number of each of the ventilation piping and the air supply piping is only one.

3. The gas turbine cogeneration system according to claim 1 , comprising:
a gas detector that is provided in the heat recovery steam generator and that outputs a detection signal to the computer; and
an output unit that outputs a detection result of the gas detector on the basis of an output signal from the computer.

4. The gas turbine cogeneration system according to claim 1 , comprising:
a gas detector that is provided in the heat recovery steam generator and that outputs a detection signal to the computer; and
an air flow control valve that is provided in the air supply piping, wherein
the computer is programed to increase an opening of the air flow control valve in a case in which a component of a gaseous fuel having a concentration equal to or higher than a set value is present and to reduce the opening of the air flow control valve in a case otherwise, on the basis of the detection signal of the gas detector during the operation using the bypass stack.

5. An operation mode change method for a gas turbine cogeneration system including: a gas turbine; a heat recovery steam generator, a bypass stack provided upstream of the heat recovery steam generator in a gas turbine exhaust gas path; and a bypass damper that opens/closes the bypass stack, wherein
the heat recovery steam generator includes:
a duct burner;
a main shut-off valve that is provided in a fuel line of the duct burner;
a fuel shut-off valve that is provided upstream of the main shut-off valve in the fuel line of the duct burner;
an air supply piping that joins the fuel line at a position upstream of the main shut-off valve and downstream of the fuel shut-off valve;
an air supply shut-off valve that is provided in the air supply piping;
a ventilation piping that is branched off from the fuel line at a position upstream of the main shut-off valve and downstream of the fuel shut-off valve; and
a ventilation shut-off valve that is provided in the ventilation piping,
the operation mode change method comprising steps of:
during an operation using the bypass stack, closing an inlet of the heat recovery steam generator to open the bypass stack, closing the main shut-off valve and the fuel shut-off valve, and opening the air supply shut-off valve and the ventilation shut-off valve, thereby always executing a purge between the main shut-off valve and the fuel shut-off valve of the fuel line with air by opening the air supply piping and the ventilation piping; and
at a time of changing to an operation using the heat recovery steam generator, opening the inlet of the heat recovery steam generator to close the bypass stack without shutting down the gas turbine to close the bypass stack, and opening the main shut-off valve and the fuel shut-off valve.

Assignees

• Mitsubishi Power Ltd

Inventors

• Murata Shigeto

Classifications

• 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

• F22B35/007

  Control systems for waste heat boilers · CPC title

• Y02E20/16

  Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT] · CPC title

• F01K23/101 Primary

  Regulating means specially adapted therefor (F01K23/105, F01K23/108 take precedence) · CPC title

• F01K23/105

  Regulating means specially adapted therefor · CPC title