JP4287989B2 - Abnormality detection method for gas turbine fuel supply system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an abnormality detection method in a gas turbine fuel supply apparatus for supplying fuel to a gas turbine, and more particularly to an abnormality detection method for detecting a gas leak from a control valve provided in a fuel flow path.
[0002]
[Prior art]
As a gas turbine fuel supply device (hereinafter, also simply referred to as “fuel supply device”), the one having the configuration shown in FIG. 1 is known.
This fuel supply device includes an LNG tank (fuel storage) 1 for storing LNG (liquefied natural gas) as fuel, an N ₂ cylinder (purge gas storage) 2 for storing nitrogen (N ₂ ) gas (purge gas), a fuel flow path 3 for supplying the fuel to the gas turbine 100 from the LNG tank 1, and _{N 2} gas cylinder 2 _{N N 2} flow path for supplying ₂ gas to the fuel flow path 3 (purge passage) 4, is provided Yes.
[0003]
A fuel flow path 3 is connected to the LNG tank 1, and a fuel supply valve 11 for controlling the fuel supply amount is provided on the 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. It has 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 adjustment valve (control valve) 51 and a main fuel flow rate adjustment 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 sandwiched between the main fuel pressure adjustment valve 51 and the main fuel flow rate adjustment valve 52 is referred to as an inter-control valve main fuel flow path (inter-control valve fuel flow path). 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 rate control valve 54 are connected to the pilot fuel flow path between the control valves (fuel flow path between control valves) 32a. , Respectively. Pressure gauges (not shown) are provided in the inter-control valve main fuel flow path 31a and the inter-control valve pilot fuel flow path 32a. These pressure gauges are connected to a determination circuit (not shown), and an alarm is issued from the determination circuit when a pressure abnormality is detected.
Further, a release path 33 having a release end 33a and an open valve 33b is provided between the fuel supply valve 11 and the branch point A in the fuel flow path 31. By opening and closing the open valve 33b, the fuel flow is reduced. Road 3 can be released into the atmosphere.
[0004]
One end side of the N ₂ flow path 4 is connected to the N ₂ cylinder 2.
The N ₂ flow path 4, and supplies the main fuel seal _{N 2} flow path 41 for supplying _{N 2} gas to the main fuel passage 31a between the control valve, the _{N 2} gas to the pilot fuel passage 32a between the control valve and pilot seal N ₂ flow path 42 for is provided. The pilot seal N ₂ flow path 42 is branched from the main fuel seal N ₂ flow path 41 at a branch point D. The main fuel seal N ₂ flow path 41 is connected to the control valve main fuel flow path 31a at the other end side at the connection point E, and the pilot seal N ₂ flow path 42 is connected to the other end side at the connection point F. Is connected to the pilot fuel flow path 32a between the control valves.
A first N ₂ supply valve for controlling the amount of N ₂ gas supplied to the inter-control valve main fuel flow path 31a is between the branch point D and the connection point E of the main fuel seal N ₂ flow path 41. 61, the pilot seal N ₂ flow path 42 is provided with a _second N ₂ supply valve 62 for controlling the amount of N ₂ gas supplied to the inter-control valve pilot fuel flow path 32a.
[0005]
When the gas turbine 100 is in a pilot operation, the fuel supply device opens the fuel supply valve 11, the pilot fuel pressure adjustment valve 53, and the pilot fuel flow rate adjustment valve 54, and closes all other valves shown in the figure to make the pilot. The fuel flow path 32 is opened so that the pilot fuel is supplied to the gas turbine 100. The pressure of the pilot fuel is adjusted by the pilot fuel pressure adjustment valve 53, the flow rate is adjusted by the pilot fuel flow rate adjustment valve 54, and the pilot fuel is supplied to the gas turbine 100.
Further, during normal operation of the gas turbine 100, the fuel supply valve 11, the pilot fuel pressure adjustment valve 53, the pilot fuel flow rate adjustment valve 54, the main fuel pressure adjustment valve 51, and the main fuel flow rate adjustment valve 52 are opened. All the illustrated valves are closed, and the pilot fuel passage 32 and the main fuel passage 31 are opened, so that the pilot fuel and the main fuel are supplied to the gas turbine 100. The pressure of the main fuel is adjusted by the main fuel pressure adjustment valve 51, the flow rate is adjusted by the main fuel flow rate adjustment valve 52, and the main fuel is supplied to the gas turbine 100.
[0006]
After the gas turbine 100 is stopped, not only the fuel flow path 3 is closed, but also high pressure N ₂ gas is filled in the middle of the fuel flow path 3 so that each fuel on the fuel tank 1 side and the gas turbine 100 side is filled. The flow paths 3 are isolated from each other.
That is, for the pilot fuel flow path 32, the pilot fuel flow rate adjustment valve 54 is first closed, then the second N ₂ supply valve 62 is opened, and the pilot seal N ₂ flow path 42 to the inter-control valve pilot fuel flow path 32a. N ₂ gas is supplied to the fuel gas to sufficiently purge the fuel remaining in the pilot fuel flow path 32a between the control valves. After the purge is completed, the pilot fuel pressure control valve 53 is closed, and the pilot fuel flow path 32a between the control valves is filled with N ₂ gas until a predetermined pressure is reached. By doing so, the pilot fuel passage 32 is isolated from the pilot fuel passage 32a between the control valves.
For the main fuel flow path 31, first, the main fuel flow rate adjustment valve 52 is closed, then the first N ₂ supply valve 61 is opened, and the main fuel seal N ₂ flow path 41 to the main fuel flow path between the control valves. N ₂ gas is supplied to 31a, and the fuel staying in the main fuel flow path 31a between the control valves is sufficiently purged. After purging, the main fuel pressure control valve 51 is closed, and the main fuel flow path 31a between control valves is filled with N ₂ gas until a predetermined pressure is reached. By doing so, the main fuel flow passage 31 is isolated from the main fuel flow passage 31a between the control valves.
The predetermined pressure is usually about 3 MPa. The reason for applying such a high pressure is to make it higher than the fuel supply pressure to avoid the risk of fuel flowing into the inter-control valve main fuel flow path 31a and the inter-control valve pilot fuel flow path 32a, that is, the gas turbine 100. This is because it is necessary to more reliably shut off the fuel supply to the vehicle.
[0007]
Leakage from the valve, in particular, fuel leakage from a control valve such as the main fuel pressure control valve 51, the main fuel flow control valve 52, the pilot fuel pressure control valve 53 or the pilot fuel flow control valve 54 is controlled from the standpoint of safety. It is not desirable from the viewpoint of ensuring soundness, and a leak check for detecting the amount of gas leakage must be performed as appropriate. Conventionally, it is only allowed to stand with a high pressure of about 3 MPa as described above, and a large amount of N ₂ gas is required when there is a slight leak from each of the control valves 51 to 54.
As described above, N ₂ gas filling is performed for the purpose of closing and isolating the fuel flow path 3, and the abnormality detection of the control valves 51 to 54 is not actively performed. That is, the abnormality detection method performed for the purpose of detecting abnormality of each control valve 51-54 has not been fully established.
[0008]
[Problems to be solved by the invention]
It is practically impossible to completely eliminate leaks from these valves. Therefore, each control valve 51 to 54 also has an allowable leak amount during operation in consideration of its structure and size. It has been established. However, this allowable leak amount is set only under the condition of operation of the gas turbine 100, and whether or not the leak amount under the high pressure as described above exceeds the allowable leak amount during operation. Strictly, it could not be detected or confirmed. That is, even if the control valve leaks within a range that does not cause any trouble during operation, it is left for a long time under high pressure conditions, so the absolute leak amount of the purge gas such as N ₂ gas becomes enormous, It was uneconomical.
Thus, as a result of intensive studies, the present inventors have found a detection method that can detect an abnormality of a control valve more accurately by performing a certain procedure under certain conditions even at a low pressure.
[0009]
The present invention has been made in view of the above circumstances, and detects the valve that causes an abnormal leak quickly and accurately and suppresses the leak amount of the purge gas, thereby improving the reliability of the gas turbine fuel supply device and operating the valve. It is an object of the present invention to provide an abnormality detection method for a gas turbine fuel supply apparatus that can reduce costs.
[0010]
[Means for Solving the Problems]
The present invention includes 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, and the fuel flow path And a purge gas passage for supplying a purge gas to a fuel passage between control valves sandwiched between the control valves, and a method for detecting an abnormality in the gas turbine fuel supply apparatus, Is purged with the purge gas, the control valve is closed, and the purge gas is filled into the inter-control valve fuel flow path so that the internal pressure of the inter-control valve fuel flow path becomes 0.80 MPa to 0.69 MPa, the aged 3 minutes while maintaining the filling state of the purge gas, when the internal pressure is equal to or less than 0.59MPa, the ones judged that the abnormality in at least one of the control valves has occurred A.
[0011]
By adopting such a configuration, the purge gas is filled in the fuel flow path between the control valves at a lower pressure than in the past, so that the control valve leak check can be performed under a lower pressure condition than during actual operation, and an abnormality can be detected. . As a result, it is possible to quickly and accurately detect a control valve having an abnormal leak. In addition, the absolute amount of purge gas that leaks can be suppressed by using a low pressure.
In addition, an internal pressure sufficient for performing a leak check can be applied 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 low pressure conditions.
And, if the specified time is 3 minutes and the specified value is 0.59 MPa, the conditions for performing the leak check can be optimized, and the abnormally leaking control valve can be detected more quickly and accurately. Can do.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of an abnormality detection method for a gas turbine fuel supply apparatus according to the present invention will be described with reference to FIG.
In addition, since the apparatus structure of a gas turbine fuel supply apparatus is the same as that of a prior art example, detailed description about each component is abbreviate | omitted.
This abnormality detection method goes through the procedures shown in (1) to (7) below. As a preliminary preparation, after the gas turbine 100 is stopped, the fuel supply valve 11 is closed, the open valve 33b is opened, and the fuel flow path 3 is opened to the atmosphere.
[0013]
(1) First, the pilot fuel pressure control valve 53 and the main fuel pressure control valve 51 are opened, and the inter-control valve pilot fuel flow path 32a and the inter-control valve main fuel flow path 31a are depressurized. The time required for this depressurization is about 5 seconds.
(2) The pilot fuel pressure control valve 53 and the main fuel pressure control valve 51 are left open, the second N ₂ supply valve 62 and the first N ₂ supply valve 61 are opened, and the control fuel in the pilot fuel flow path 32a is controlled. N ₂ gas purging of the fuel respectively staying in the inter-valve main fuel flow path 31a is performed. The time required for this purge is about 30 seconds.
[0014]
(3) The pilot fuel pressure control valve 53 and the main fuel pressure control valve 51 are closed, and the internal pressures of the inter-control valve pilot fuel flow path 32a and the inter-control valve main fuel flow path 31a are respectively set to 0. The N ₂ gas is filled in the inter-control valve pilot fuel flow path 32a and the inter-control valve main fuel flow path 31a so that the value is 6 9 MPa or more and 0.80 MPa or less. The reason why the internal pressure is set 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, increasing the filling pressure of the N ₂ gas, in order to uneconomical use of the N ₂ gas. It takes at least 2 minutes from the start of filling until the internal pressure rises within the above range.
[0015]
(4) When the internal pressure value of the N ₂ gas falls within the above range, the second N ₂ supply valve 62 and the first N ₂ supply valve 61 are closed, and a leak check is started. That is, 3 minutes, which is a predetermined time, is allowed to elapse while the N ₂ gas filling state is maintained.
The reason for setting the specified time to 3 minutes is that, as a result of the study by the present inventors, it was found that the presence of leak could be sufficiently checked at this time under the above pressure. .
[0016]
(5) When 3 minutes have elapsed since the start of the leak check, the internal pressure of the pilot fuel flow path 32a between the control valves or the internal pressure of the main fuel flow path 31a between the control valves is from a predetermined specified value of 0.59 MPa. If it is larger, it is determined that no abnormality has occurred in each of the control valves 51-54. Such a determination is performed by a determination circuit in response to a measurement value from the pressure valve. In this case, since it has been determined to be normal, the determination circuit does not issue an alarm.
[0017]
If at least one of the internal pressure of the pilot fuel flow path 32a between the control valves or the internal pressure of the main fuel flow path 31a between the control valves is 0.59 MPa or less, there is an abnormality in at least one of the control valves 51 to 54. Determine that it has occurred. That is, if the internal pressure of the pilot fuel flow path 32a between the control valves is 0.59 MPa or less, the leak from at least one of the pilot fuel pressure control valve 53 or the pilot fuel flow rate control valve 54 exceeds the allowable leak amount. Is determined. If the internal pressure of the main fuel flow path 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 adjustment valve 51 or the main fuel flow rate adjustment valve 52 exceeds the allowable leak amount. To do. In these cases, since the determination circuit determines that there is an abnormality, an alarm is issued.
The specified value is calculated from the allowable leak amount of the control valves 51 to 54, the pipe internal volume of the inter-control valve pilot fuel flow path 32a or the inter-control valve main fuel flow path 31a, and the like. Here, the internal pressure value of the pilot fuel flow path 32a between control valves or the main fuel flow path 31a between control valves, which is calculated when the upper limit of the allowable leak amount of each control valve 51 to 54 leaks, is approximately 0. An internal pressure value higher by .1 to 0.2 MPa, that is, 0.59 MPa is defined as a specified value.
[0018]
(6) The pilot fuel pressure control valve 52 and the main fuel pressure control valve 51 are opened, and the inter-control valve pilot fuel flow path 32a and the inter-control valve main fuel flow path 31a are depressurized. The time required for this 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 to complete the leak check and the series of abnormality detection procedures.
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 is performed. When it is determined that an abnormality has occurred in at least one of the control valves 51 to 54, which control valve has an abnormality is inspected in detail until the next operation of the gas turbine 100 is performed During this period, the control valve is repaired or replaced.
[0019]
In the abnormality detection method for the gas turbine fuel supply apparatus according to the present embodiment, N ₂ gas is supplied to the inter-control valve main fuel flow path 31a and the inter-control valve pilot fuel flow at 0.80 MPa or less, which is considerably lower than the conventional 3 MPa. By filling the passage 32a, a leak check of the control valves 51 to 54 can be performed under a lower pressure condition during actual operation to detect an abnormality. This makes it possible to quickly and accurately detect abnormally leaking control valves, suppress work loss such as repairing or replacing normal control valves, increasing reliability, and reducing operating costs. Can be achieved.
Further, by setting the pressure low, the absolute amount of leaking N ₂ gas can be suppressed, the amount of N ₂ gas used can be reduced, and the cost can be reduced.
[0020]
Furthermore, since the N ₂ gas is filled so that the internal pressure of the main fuel flow path 31a between the control valves and the pilot fuel flow path 32a between the control valves is 0.69 MPa or more, each control valve 51 to 54 is filled. It is possible to easily check for abnormal leaks, and it is possible to use N ₂ gas economically and to improve the reliability of the leak check.
[0021]
Furthermore, since the specified time is set to 3 minutes and the specified value is set to 0.59 MPa, the presence or absence of leak can be checked sufficiently in a short time, and the allowable leak amount of the control valves 51 to 54 can be checked. When the upper limit amount leaks, it is determined that there is an abnormality. Therefore, if there is an abnormality sign in the control valves 51 to 54, 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 improved.
[0022]
In the above embodiment, the fuel supply device is kept waiting after the end of the series of abnormality detection procedures. However, in order to ensure safety, the N ₂ purge is performed as in the conventional example. You may go.
[0023]
【The invention's effect】
As described above, according to the abnormality detection method for a gas turbine fuel supply apparatus according to the present invention, a gas turbine fuel can be detected by quickly and accurately detecting an abnormal leak valve and suppressing the leak amount of purge gas. An abnormality detection method for a gas turbine fuel supply apparatus that can increase the reliability of the supply apparatus and reduce the operating cost can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a gas turbine fuel supply apparatus for carrying out an embodiment of the present invention.
[Explanation of symbols]
1 LNG tank (fuel storage)
2 N ₂ cylinder (purge gas storage)
3 Fuel flow path 4 N ₂ 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 N ₂ flow path 42 Pilot seal N ₂ 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 N ₂ supply valve 62 2nd N ₂ supply valve 100 gas turbine

Claims (1)

A fuel storage,
A purge gas storage;
A fuel flow path for supplying fuel to the gas turbine from the fuel storage;
A plurality of control valves provided in the middle of the fuel flow path;
A purge gas passage for supplying a purge gas to a fuel passage between control valves sandwiched between the control valves of the fuel passage, and a method for detecting an abnormality in a gas turbine fuel supply device comprising:
Purging the fuel flow path between the control valves with the purge gas,
The control valve is closed and the purge gas is filled into the inter-control valve fuel flow path so that the internal pressure of the inter-control valve fuel flow path is 0.80 MPa to 0.69 MPa,
It is determined that an abnormality has occurred in at least one of the control valves when the internal pressure becomes 0.59 MPa or less after 3 minutes with the purge gas filled. An abnormality detection method for a gas turbine fuel supply apparatus.

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