Method for purging fuel channel, purging device for executing said method, and gas turbine installation provided with said device

Patent metadata

Field	Value
Publication number	US-10378448-B2
Application number	US-201515304945-A
Country	US
Kind code	B2
Filing date	May 28, 2015
Priority date	Jun 3, 2014
Publication date	Aug 13, 2019
Grant date	Aug 13, 2019

Abstract

A water supplying step of supplying water to a liquid-fuel channel of a nozzle is executed during a liquid fuel supply state in which only liquid fuel is supplied to the nozzle; a post-switch water purging step of supplying water to the liquid-fuel channel of the nozzle is executed during a gas fuel supply state in which only gas fuel is supplied to the nozzle; and a mid-switch water purging step of supplying water to the liquid-fuel channel of the nozzle is executed during a fuel switching state which is a state of transition from the liquid fuel supply state to the liquid fuel supply state. A second flow rate of water supplied in the mid-switch water purging step is lower than a first flow rate of water supplied in the water supplying step. In the post-switch water purging step, water is temporarily supplied at a third flow rate which is higher than the second flow rate.

First claim

The invention claimed is:

1. A method for purging at least one fuel channel in a combustor having a nozzle that selectively sprays a liquid fuel and a gas fuel, the nozzle having formed therein a first liquid-fuel channel of the at least one fuel channel, through which the liquid fuel flows and which is open at a first tip portion of the nozzle, and a first gas-fuel channel of the at least one fuel channel, through which the gas fuel flows and which is open at the first tip portion of the nozzle, the method for purging the fuel channel comprising:
a water supplying step of supplying water to the first liquid-fuel channel in a first liquid fuel supply state in which, of the liquid fuel and the gas fuel, only the liquid fuel is supplied to the nozzle;
a mid-switch water purging step of supplying the water to the first liquid-fuel channel during a fuel switching state, during which, from the first liquid fuel supply state, the liquid fuel being supplied to the first liquid-fuel channel of the nozzle decreases while the gas fuel starts to be supplied to the first gas-fuel channel of the nozzle, and the gas fuel supplied to the first gas-fuel channel increases; and
a post-switch water purging step of supplying the water to the first liquid-fuel channel after the fuel switching state has ended as a result of the liquid fuel no longer being supplied to the first liquid-fuel channel, and only the gas fuel, of the liquid fuel and the gas fuel, starts being supplied to the nozzle, wherein
in the mid-switch water purging step, the water of a second flow rate value is supplied to the first liquid-fuel channel, the second flow rate value being lower than a first flow rate value that is a flow rate of the water supplied to the first liquid-fuel channel in the water supplying step, and
in the post-switch water purging step, the water of a third flow rate value is at least temporarily supplied to the first liquid-fuel channel, the third flow rate value being higher than the second flow rate value.

2. The method for purging the at least one fuel channel according to claim 1 ,
wherein the third flow rate value is lower than the first flow rate value.

3. The method for purging the at least one fuel channel according to claim 1 , wherein
the post-switch water purging step includes a water replacement step of supplying the water of the second flow rate value to the first liquid-fuel channel continuously from the mid-switch water purging step, and
a cleaning step of supplying the water of the third flow rate value to the first liquid-fuel channel after the water replacement step.

4. The method for purging the at least one fuel channel according to claim 3 , wherein
the post-switch water purging step includes an intermittent purging step of intermittently supplying the water to the first liquid-fuel channel after the cleaning step, and
the water of the third flow rate value is supplied to the first liquid-fuel channel in the intermittent purging step.

5. The method for purging the at least one fuel channel according to claim 1 , wherein
in the water supplying step, the first low rate value of the water supplied to the first liquid-fuel channel is caused to gradually become lower before the fuel switching state is reached, such that the flow rate of the water supplied to the first liquid-fuel channel becomes the second flow rate value at a timing at which the fuel switching state is reached.

6. The method for purging the at least one fuel channel according to claim 1 , wherein
an air purging step is performed in which air is supplied to the first liquid-fuel channel after the post-switch water purging step is completed, and
the air purging step includes a low-pressure purging step of supplying the air of a first pressure to the first liquid-fuel channel, and a high-pressure purging step of supplying the air of a second pressure to the first liquid-fuel channel after the low-pressure purging step, the second pressure being higher than the first pressure.

7. The method for purging the at least one fuel channel according to claim 1 , wherein
the combustor includes a second nozzle as well as the nozzle that functions as a first nozzle, the second nozzle having formed therein a second liquid-fuel channel, through which the liquid fuel flows and which is open at a second tip portion of the second nozzle, and a second gas-fuel channel, through which the gas fuel flows and which is open at the second tip portion of the second nozzle, and
an air purging step of supplying air to the second liquid-fuel channel of the second nozzle is performed at a timing at which, from a second liquid fuel supply state in which, of the liquid fuel and the gas fuel, only the liquid fuel is supplied to the second nozzle, the liquid fuel is no longer supplied to the second nozzle and only the gas fuel is being supplied to the second nozzle, and the post-switch water purging step for the first nozzle is being performed.

8. The method for purging the at least one fuel channel according to claim 3 , wherein
the combustor includes a second nozzle as well as the nozzle that functions as a first nozzle, the second nozzle having formed therein a second liquid-fuel channel of the at least one fuel channel, through which the liquid fuel flows and which is open at a second tip portion of the second nozzle, and a second gas-fuel channel of the at least one fuel channel, through which the gas fuel flows and which is open at the second tip portion of the second nozzle,
an air purging step of supplying air to the second liquid-fuel channel of the second nozzle is performed at a timing at which, from a second liquid fuel supply state in which, of the liquid fuel and the gas fuel, only the liquid fuel is supplied to the second nozzle, the liquid fuel is no longer supplied to the second nozzle and only the gas fuel is being supplied to the second nozzle, and the post-switch water purging step for the first nozzle is being performed, and
the air purging step for the second nozzle is started at the timing at which the cleaning step for the first nozzle is started.

9. The method for purging the at least one fuel channel according to claim 7 , wherein
the air purging step for the second nozzle includes a low-pressure purging step of supplying the air of a third pressure to the second liquid-fuel channel of the second nozzle, and a high-pressure purging step of supplying the air of a fourth pressure to the second liquid-fuel channel of the second nozzle after the low-pressure purging step for the second nozzle, the fourth pressure being higher than the third pressure.

10. The method for purging the at least one fuel channel according to claim 7 , wherein
the second nozzle burns the liquid fuel or the gas fuel sprayed from the second nozzle by diffusion combustion, and
after a first air purging step, which is the air purging step for the second nozzle, a second air purging step is performed, in which the air having a second pressure lower than a first pressure of the air supplied to the second liquid-fuel channel of the second nozzle in the first air purging step is supplied to the second liquid-fuel channel of the second nozzle.

11. A purging device for at least one fuel channel in a combustor having a nozzle that selectively sprays a liquid fuel and a gas fuel, the nozzle having formed therein a first liquid-fuel channel of the at least one fuel channel, through which the liquid fuel flows and which is open at a first tip portion of the nozzle, and a first gas-fuel channel of the at least one fuel channel, through which the gas fuel flows and which is open at the first tip portion of the nozzle, the purging device comprising:
a water line that supplie

Assignees

• Mitsubishi Hitachi Power Sys

Inventors

• Nakahara Hisashi

Classifications

• F23R3/283

  Attaching or cooling of fuel injecting means including supports for fuel injectors, stems, or lances · CPC title

• F23R3/28

  characterised by the fuel supply (burners F23D) · CPC title

• F23K5/18

  Cleaning or purging devices, e.g. filters · CPC title

• F23R2900/00004

  Preventing formation of deposits on surfaces of gas turbine components, e.g. coke deposits · CPC title

• F05D2260/602

  Drainage · CPC title