JP2002013418A - Abnormality detection method for gas turbine fuel supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an abnormality detection method for a gas turbine fuel supply device capable of improving reliability of the gas turbine fuel supply device and reducing driving cost. SOLUTION: This is a method to detect abnormality in the gas turbine fuel supply device furnished with an LNG tank 1, an N2 cylinder 2, a fuel channel 3 to supply fuel to a gas turbine 100 from the LNG tank 1, a plural number of control valves 51-54 provided in the middle of the fuel channel 3 and an N2 channel 4 to supply N2 gas to fuel channels 31a, 32a between the control valves, insides of the fuel channels 31a, 32a between the control valves are purged with N2 gas, the control valves 51-54 are closed, N2 gas is filled so that internal pressure of the fuel channels 31a, 32a between the control valves becomes less than 0.80 MPa, and it is judged that at least one of the control valves 51-54 has abnormality in the case when the internal pressure is lowered to a specified value when specified time passes while such a filling state is maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting an abnormality in a gas turbine fuel supply system for supplying fuel to a gas turbine, and more particularly, to an abnormality detection method for detecting gas leakage from a control valve provided in a fuel flow path. About.

[0002]

2. Description of the Related Art As a gas turbine fuel supply device (hereinafter, also simply referred to as "fuel supply device"), one having a configuration shown in FIG. 1 is known. The fuel supply device includes an LNG tank (fuel storage) 1 for storing LNG (liquefied natural gas) as a fuel, and a nitrogen (N2) gas (purge gas).
(Purge gas storage) 2 for storing LN and LN
A fuel passage 3 for supplying fuel from the G tank 1 to the gas turbine 100 and an N2 passage (purge gas passage) 4 for supplying N2 gas of the N2 cylinder 2 to the fuel passage 3 are provided.

[0003] A fuel flow path 3 is connected to the LNG tank 1, and a fuel supply valve 11 for controlling a fuel supply amount is provided on an outlet side thereof. The fuel flow path 3 includes a main fuel flow path 31 for supplying main fuel during normal operation of the gas turbine 100 and a pilot fuel flow path 32 for supplying pilot fuel during pilot operation of the gas turbine 100. Have been. The pilot fuel flow path is branched from the main fuel flow path 31 at a branch point A.
The main fuel flow path 31 is provided with a main fuel pressure control valve (control valve) 51 and a main fuel flow rate control valve (control valve) 52. The pilot fuel flow path 32 is provided with a pilot fuel pressure control valve (control valve) 53 and a pilot fuel flow rate control valve (control valve) 54. In the following, a portion of the main fuel flow path 31 interposed between the main fuel pressure control valve 51 and the main fuel flow rate control valve 52 is referred to as a main fuel flow path between control valves (fuel flow path between control valves).
31a and a portion of the pilot fuel flow path 32 sandwiched between the pilot fuel pressure control valve 53 and the pilot fuel flow control valve 54 are referred to as a control valve pilot fuel flow path (control valve fuel flow path) 32a. , Respectively. A pressure gauge (not shown) is provided in each of the control valve main fuel passage 31a and the control valve pilot fuel passage 32a. These pressure gauges are connected to a judgment circuit (not shown), and when a pressure abnormality is detected, an alarm is issued from the judgment circuit. Further, a release path 33 having a release end 33a and a release valve 33b is provided between the fuel supply valve 11 and the branch point A in the fuel flow path 31.
The opening and closing of the release valve 33b allows the fuel flow path 3 to be released to the atmosphere.

[0004] One end of an N2 flow path 4 is connected to the N2 cylinder 2. The N2 flow path 4 includes a main fuel seal N2 flow path 41 for supplying N2 gas to the control valve main fuel flow path 31a, and a control valve pilot fuel flow path 32a.
And a pilot seal N2 flow path 42 for supplying an N2 gas to the air conditioner. Pilot seal N2 flow path 4
2 is branched from the main fuel seal N2 flow path 41 at a branch point D. The other end of the main fuel seal N2 flow path 41 is connected to the inter-control-valve main fuel flow path 31a at a connection point E, and the pilot seal N2 flow path 42
Pilot fuel flow path 3 between control valve and other end at connection point F
2a. A first N2 supply valve 61 for controlling the supply amount of N2 gas to the inter-control valve main fuel flow path 31a is provided between the branch point D and the connection point E of the main fuel seal N2 flow path 41. Pilot seal N2 flow path 4
2 is provided with a second N2 supply valve 62 for controlling the supply amount of N2 gas to the pilot fuel flow path 32a between control valves.

[0005] This fuel supply device is a gas turbine 100
During the pilot operation, the fuel supply valve 11, the pilot fuel pressure control valve 53, and the pilot fuel flow control valve 54
Is opened, and all the other valves shown are closed to open the pilot fuel flow path 32 so that the pilot fuel is supplied to the gas turbine 100. The pilot fuel is regulated in pressure by a pilot fuel pressure regulating valve 53, regulated in flow by a pilot fuel flow regulating valve 54, and supplied to the gas turbine 100. During normal operation of the gas turbine 100, the fuel supply valve 11, the pilot fuel pressure control valve 53, and the pilot fuel flow control valve 5
4. The main fuel pressure control valve 51 and the main fuel flow control valve 52 are opened, and the other valves shown in the figures are all closed, and the pilot fuel flow path 32 and the main fuel flow path 31 are closed.
Is opened so that the pilot fuel and the main fuel are supplied to the gas turbine 100. The main fuel is controlled in pressure by the main fuel pressure control valve 51 and the flow rate is controlled by the main fuel flow control valve 52, so that the gas turbine 100
Supplied to

After stopping the gas turbine 100, not only the fuel flow path 3 is closed but also a high pressure N2 gas is filled in the middle of the fuel flow path 3 so that each of the fuel tank 1 side and the gas turbine 100 side can be closed. Are separated from each other. That is, with respect to the pilot fuel flow path 32, first, the pilot fuel flow rate control valve 54 is closed, then the second N2 supply valve 62 is opened, and the N2 gas flows from the pilot seal N2 flow path 42 to the pilot fuel flow path 32a between control valves. Supply gas,
The fuel remaining in the pilot fuel passage 32a between the control valves is sufficiently purged. After the purge is completed, the pilot fuel pressure control valve 53 is closed, and N2 gas is filled in the pilot fuel flow path 32a between the control valves until a predetermined pressure is reached. By doing so, the pilot fuel passage 32a between the control valves is provided.
The pilot fuel flow path 32 is isolated from the boundary. For the main fuel flow passage 31, first, the main fuel flow control valve 52 is closed, and then the first N2 supply valve 61 is opened to move the main fuel seal N2 flow passage 41 to the control valve main fuel flow passage 31a. The N2 gas is supplied to sufficiently purge the fuel remaining in the main fuel passage 31a between the control valves. After completion of the purge, the main fuel pressure regulating valve 51 is closed, and the inter-control valve main fuel flow path 31a is filled with N2 gas until a predetermined pressure is reached. By doing so, the main fuel passage 31a is separated from the main fuel passage 31a between the control valves.
Is isolated. The above-mentioned predetermined pressure is usually about 3 MPa
It is. Such a high pressure is applied to prevent the danger of fuel flowing into the inter-control-valve main fuel flow passage 31a and the inter-control-valve pilot fuel flow passage 32a by making the pressure higher than the fuel supply pressure. This is because it is necessary to more reliably shut off the fuel supply to the engine.

Leakage from the valves, in particular, main fuel pressure control valve 51, main fuel flow control valve 52, pilot fuel pressure control valve 53 or pilot fuel flow control valve 5
Fuel leakage from a control valve such as 4 is not desirable from the viewpoint of security and ensuring the soundness of control, and a leak check for detecting the amount of gas leakage must be appropriately performed.
Conventionally, only a high pressure of about 3 MPa is left as described above, and a large amount of N2 gas is required when there is a small leak from each of the control valves 51 to 54. As described above, N2 gas is charged for the purpose of closing and isolating the fuel flow path 3, and abnormality detection of each of the control valves 51 to 54 is not actively performed. That is, an abnormality detection method for detecting an abnormality of each of the control valves 51 to 54 has not been sufficiently established.

[0008]

It is practically impossible to completely eliminate such leaks from the valves. Therefore, each of the control valves 51 to 54 must be designed in consideration of its structure and size. The allowable leak amount during operation is determined individually. However, this allowable leak amount is set only under the condition that the gas turbine 100 is operated, and it is not determined whether the leak amount under the high pressure exceeds the allowable leak amount during the operation as described above. Strictly, it could not be detected and confirmed. That is, even if the control valve leaks within a range that does not cause any trouble during operation, since the control valve is left for a long time under high pressure conditions, the absolute leakage amount of the purge gas such as N2 gas becomes enormous. It was economic. Therefore, the present inventors have conducted intensive studies and as a result, have found a detection method that can more accurately detect an abnormality of the control valve if a certain procedure is performed under certain conditions even at a low pressure.

The present invention has been made in view of the above circumstances, and quickly and accurately detects an abnormally leaking valve and suppresses the amount of purge gas leak, thereby improving the reliability of a gas turbine fuel supply device. It is an object of the present invention to provide a method for detecting an abnormality of a gas turbine fuel supply device that can increase the operating cost and reduce the operating cost.

[0010]

According to a first aspect of the present invention, there is provided a fuel storage, a purge gas storage, a fuel passage for supplying fuel from the fuel storage to a gas turbine, and a fuel passage provided in the fuel passage. A plurality of control valves, and a purge gas flow path for supplying a purge gas to a control valve fuel flow path interposed between the control valves among the fuel flow paths. Purging the inside of the inter-control valve fuel flow path with the purge gas, closing the control valves, and supplying the purge gas so that the internal pressure of the inter-control valve fuel flow path is 0.80 MPa or less. When the internal pressure has decreased to a predetermined value when a predetermined time has elapsed while the fuel gas flow path between the control valves is filled and the charged state of the purge gas is maintained, the control valve of And judging at least one abnormal has occurred Chino.

With this configuration, the purge gas is filled into the fuel flow path between the control valves at a lower pressure than in the prior art. Can be detected. Thus, a control valve having an abnormal leak can be quickly and accurately detected. Further, by setting the pressure to be low, the absolute amount of the purge gas leaking can be suppressed.

According to a second aspect of the present invention, there is provided the gas turbine fuel supply device abnormality detecting method according to the first aspect,
The purge gas is filled into the inter-control valve fuel passage so that the internal pressure of the inter-control valve fuel passage becomes 0.69 MPa or more. According to a third aspect of the present invention, there is provided the gas turbine fuel supply device abnormality detecting method according to the first or second aspect, wherein the specified time is 3 minutes, and the specified value is 0.59 MPa. It is characterized by having done.

[0013] With this configuration, it is possible to apply an internal pressure that is preferable for performing a leak check to the fuel flow path between the control valves. Therefore, it is possible to avoid a risk that a control valve that causes an abnormal leak during operation is overlooked even under a low pressure condition. And the specified time is 3
When the specified value is 0.59 MPa, the conditions for performing the leak check can be optimized, and the control valve having an abnormal leak can be detected more quickly and accurately.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for detecting an abnormality of a gas turbine fuel supply device according to the present invention will be described below with reference to FIG. Since the configuration of the gas turbine fuel supply device is the same as that of the conventional example, a detailed description of each component will be omitted. This abnormality detection method goes through the following procedures (1) to (7). As a preliminary preparation, after stopping the gas turbine 100, the fuel supply valve 11
Is closed and the open valve 33b is opened, and the fuel flow path 3
To open to the atmosphere.

(1) First, the pilot fuel pressure control valve 53 and the main fuel pressure control valve 51 are opened to depressurize the pilot fuel flow path 32a between control valves and the main fuel flow path 31a between control valves. The time required for the depressurization is about 5 seconds. (2) While the pilot fuel pressure control valve 53 and the main fuel pressure control valve 51 remain open, the second N2 supply valve 62 and the first N2 supply valve 61 are opened, and the pilot fuel flow path 32a between the control valves and the control valve The N2 gas purge of the fuel staying in the main fuel passage 31a is performed. The time required for this purging is about 30 seconds.

(3) The pilot fuel pressure control valve 53 and the main fuel pressure control valve 51 are closed, and the pilot fuel flow path 32a between the control valves and the main fuel flow path 31a between the control valves are closed.
N2 gas is filled in the pilot fuel flow path 32a between control valves and the main fuel flow path 31a between control valves so that the internal pressures of the respective fuel cells have a value of 0.59 MPa or more and 0.80 MPa or less. The reason for setting the internal pressure in this way is that the internal pressure is determined by the mutual relationship between the allowable leak amount, the specified time for abnormality detection, and the specified pressure. Also, if the filling pressure of the N2 gas is increased, the N2 gas is used uneconomically. It takes at least 2 minutes from the start of filling until the internal pressure value increases within the above range.

(4) When the internal pressure value of the N2 gas falls within the above range, the second N2 supply valve 62 and the first N2 supply valve 61 are closed to start a leak check. That is, N2
While maintaining the gas filling state, three minutes, which is a predetermined time, is passed. The reason why the specified time is set to 3 minutes is that, as a result of the study by the present inventors, it has been found that under the above-mentioned pressure, it is possible to sufficiently check for the presence or absence of a leak in this time. .

(5) When three minutes have passed since the start of the leak check, the pilot fuel passage 32a between the control valves
If the internal pressure of the main fuel flow path between control valves or the internal pressure of the control valve main fuel passage 31a is larger than a predetermined specified value of 0.59 MPa,
It is determined that no abnormality has occurred in each of the control valves 51 to 54.
Such a determination is made by a determination circuit in response to a measurement value from the pressure valve. In this case, since it is determined that the state is normal, the determination circuit does not issue an alarm.

If at least one of the internal pressure of the pilot fuel passage 32a between control valves or the internal pressure of the main fuel passage 31a between control valves becomes 0.59 MPa or less, each control valve 5
It is determined that at least one of 1 to 54 has an abnormality. That is, the pilot fuel passage 32 between the control valves
If the internal pressure of “a” becomes 0.59 MPa or less, it is determined that the leak from at least one of the pilot fuel pressure control valve 53 and the pilot fuel flow control valve 54 exceeds the allowable leak amount. If the internal pressure of the main fuel passage 31a between the control valves is 0.59 MPa or less, it is determined that the leak from at least one of the main fuel pressure control valve 51 and the main fuel flow control valve 52 exceeds the allowable leak amount. I do. In these cases, since the determination circuit has determined that there is an abnormality, an alarm is issued. The specified value is calculated from the permissible leak amount of the control valves 51 to 54, the pipe internal volume of the pilot fuel passage 32a between control valves or the main fuel passage 31a between control valves, and the like. Here, each control valve 51
The internal pressure value of the inter-control valve pilot fuel flow path 32a or the inter-control valve main fuel flow path 31a, which is calculated when the upper limit amount of the allowable leak amount of?
An internal pressure value higher by 0.2 MPa, that is, 0.59 MPa is defined as a specified value.

(6) The pilot fuel pressure control valve 52 and the main fuel pressure control valve 51 are opened, and the pilot fuel passage 32a between control valves and the main fuel passage 31a between control valves are opened.
Is depressurized. The time required for the depressurization is about 30 seconds. (7) After the depressurization, the pilot fuel pressure control valve 52 and the main fuel pressure control valve 51 are closed, the leak check ends, and a series of abnormality detection procedures ends. If it is determined that no abnormality has occurred in each of the control valves 51 to 54, the fuel supply device is kept on standby until the next operation of the gas turbine 100. Each control valve 51-
If it is determined that at least one of the valves 54 has an abnormality, it is determined in detail which control valve has an abnormality. Repair or replace control valve.

In the method for detecting an abnormality of the gas turbine fuel supply device according to the present embodiment, the N2 gas is supplied to the main fuel passage 31a between the control valves and the pilot valve between the control valves at 0.80 MPa or less, which is considerably lower than the conventional 3 MPa. By filling the fuel passage 32a, it is possible to detect an abnormality by performing a leak check of the control valves 51 to 54 under a lower pressure condition during an actual operation. As a result, abnormally leaking control valves can be quickly and accurately detected, work loss such as repairing and replacing normal control valves is suppressed, reliability is increased, and operating costs are reduced. Can be achieved. Also,
With the low pressure, the absolute amount of the leaked N2 gas can be suppressed, the amount of the N2 gas used can be reduced, and the cost can be reduced.

Further, the internal pressures of the main fuel passage 31a between control valves and the pilot fuel passage 32a between control valves are set to 0.69.
Since the N2 gas is filled so as to be equal to or higher than MPa, it is easy to check for abnormal leaks of the control valves 51 to 54, and the N2 gas can be used economically, and the reliability of the leak check can be improved. Can be enhanced.

Further, the specified time is set to 3 minutes,
Since the specified value is set to 0.59 MPa, it is possible to sufficiently check for the presence or absence of a leak in a short time, and it is determined that there is an abnormality when the upper limit of the allowable leak amount of the control valves 51 to 54 leaks. It will be. Therefore, the control valve 5
If any of the signs 1 to 54 has an abnormality sign, it is detected, and it is possible to prevent a trouble from occurring when the gas turbine 100 is restarted. That is, the conditions for performing the leak check can be optimized, and the reliability of the leak check can be further increased.

In the above embodiment, the fuel supply device is kept on standby after the end of a series of abnormality detection procedures. However, in order to further ensure safety,
N2 purge may be performed as in the conventional example.

[0025]

As described above, according to the abnormality detection method for a gas turbine fuel supply device according to the present invention, it is possible to quickly and accurately detect a valve that has an abnormal leak and to suppress the amount of purge gas leak. Thus, it is possible to provide a method for detecting an abnormality of the gas turbine fuel supply device, which can enhance the reliability of the gas turbine fuel supply device and reduce the operation cost.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a gas turbine fuel supply device for carrying out an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 LNG tank (fuel storage) 2 N2 cylinder (purge gas storage) 3 Fuel flow path 4 N2 flow path (purge gas flow path) 31 Main fuel flow path 31a Main fuel flow path between control valves (fuel flow path between control valves) 32 Pilot Fuel flow path 32a Pilot fuel flow path between control valves (fuel flow path between control valves) 41 Main fuel seal N2 flow path 42 Pilot seal N2 flow path 51 Main fuel pressure control valve (control valve) 52 Main fuel flow control valve (control Valve) 53 Pilot fuel pressure control valve (control valve) 54 Pilot fuel flow control valve (control valve) 61 1st N2 supply valve 62 2nd N2 supply valve 100 Gas turbine

Claims (3)

[Claims] 1. A fuel storage, a purge gas storage, a fuel flow path for supplying fuel from the fuel storage to a gas turbine, a plurality of control valves provided in the middle of the fuel flow path, A purge gas flow path for supplying a purge gas to a control valve fuel flow path interposed between the control valves, a method for detecting an abnormality in the gas turbine fuel supply device, comprising: Purging the inside with the purge gas, filling each of the control valves with the purge gas into the inter-control valve fuel flow path such that the internal pressure of the inter-control valve fuel flow path becomes 0.80 MPa or less; When a predetermined time has elapsed while maintaining the charged state, if the internal pressure decreases to a predetermined value, an abnormality occurs in at least one of the control valves. Abnormality detecting method for a gas turbine fuel supply apparatus characterized by determining that that. 2. The internal pressure of the fuel passage between the control valves is 0.6.
2. The method according to claim 1, wherein the purge gas is filled into the inter-control valve fuel passage so as to have a pressure of 9 MPa or more. 3. The method according to claim 1, wherein the specified time is 3 minutes, and the specified value is 0.59 MPa.