CN118310698A - Gas turbine fuel leakage detection system and gas turbine fuel leakage detection method - Google Patents

Abstract

The invention discloses a gas turbine fuel leakage detection system and a gas turbine fuel leakage detection method, wherein the system can comprise a fuel supply main pipeline, a first balance pipeline, a second balance pipeline and a pressurizing pipeline; the fuel supply main pipeline is sequentially provided with a first cut-off valve, a second cut-off valve, a third cut-off valve, a first discharge valve, a second discharge valve, a first pressure sensor, a second pressure sensor, a combustible gas detection device and a differential pressure sensor; a first balance valve is arranged on the first balance pipeline; the second balance valve is arranged on the second balance pipeline; the pressurizing pipeline is sequentially provided with a first control valve, a second control valve, a third control valve, a check valve and a fourth control valve. By using the gas turbine fuel leakage detection system and the gas turbine fuel leakage detection method, the purging step can be omitted under the condition of ensuring no gas leakage by detecting the tightness of the related valves, the starting time is reduced, the response speed of the gas turbine is improved, and the energy consumption is reduced.

Description

Gas turbine fuel leakage detection system and gas turbine fuel leakage detection method

Technical Field

The invention relates to the technical field of gas turbines, in particular to a gas turbine fuel leakage detection system and a gas turbine fuel leakage detection method.

Background

Gas turbines require flammable gas as a motive fuel, which is explosive and therefore requires safety isolation measures, and in general, the shut-off of the flammable gas requires valve operation, but any valve may not be 100% reliable and slight leakage may cause an explosion in space.

Since the passage of the gas turbine exhaust gas to the exhaust heat boiler is large in volume, it is also difficult to secure no combustible gas in the exhaust passage by installing a gas detector in the exhaust passage.

In order to prevent possible natural gas in a boiler hearth from knocking, the gas turbine and the boiler part are purged in a high-speed turning state for 10-15 minutes before the gas turbine is started.

The fuel purging step is added, so that the starting time to the grid connection time is prolonged, the purging time is about 10-15 minutes, the starting time to the grid connection time is about 30 minutes, the purging takes up one third of the whole starting time to the grid connection time, and the starting flexibility of the gas turbine is greatly reduced.

The gas turbine sweeps for 10 minutes at 750rpm/min and also brings forced cooling of the waste heat boiler, so that waste heat storage of the waste heat boiler is caused, and additionally, cold air enters the fin tube of the waste heat boiler for forced cooling due to additional sweeping, so that the fin tube of the waste heat boiler is easy to burst and leak.

Disclosure of Invention

The invention aims to solve the technical problem of providing a gas turbine fuel leakage detection system and a gas turbine fuel leakage detection method.

First aspect

The technical scheme adopted for solving the technical problems is as follows: constructing a fuel leakage detection system of a gas turbine, comprising a fuel supply main pipeline, a first balance pipeline, a second balance pipeline and a pressurizing pipeline;

the fuel supply main pipeline is sequentially provided with a first cut-off valve, a second cut-off valve and a third cut-off valve;

A first discharge pipeline is connected between the first cut-off valve and the second cut-off valve, and a first discharge valve is arranged on the first discharge pipeline; a second discharge pipeline is arranged between the second cut-off valve and the third cut-off valve, and a second discharge valve is arranged on the second discharge pipeline;

A first pressure sensor is further arranged between the first cut-off valve and the second cut-off valve, a second pressure sensor and a combustible gas detection device are further arranged between the first cut-off valve and the third cut-off valve, and the inlet end and the outlet end of the second cut-off valve are connected with a differential pressure sensor;

The two ends of the first balance pipeline are connected with the inlet end and the outlet end of the first cut-off valve, and the first balance pipeline is provided with a first balance valve; two ends of the second balance pipeline are respectively connected with the inlet end of the first cut-off valve and the outlet end of the second cut-off valve, and the second balance pipeline is provided with a second balance valve;

The second end of the pressurizing pipeline is connected between the second cut-off valve and the third cut-off valve, and the pressurizing pipeline is sequentially provided with a first control valve, a second control valve, a third control valve, a check valve and a fourth control valve from the first end to the second end of the pressurizing pipeline.

In some embodiments, a third discharge pipe is further disposed between the second control valve and the third control valve, and a third discharge valve is disposed on the third discharge pipe.

In some embodiments, a drain pipe is further disposed between the second control valve and the third control valve, and a first drain valve and a second drain valve are disposed on the drain pipe.

In some embodiments, the second control valve and the third control valve are automatic control valves.

In some embodiments, the first control valve and the fourth control valve are manual valves.

In some embodiments, the apertures of the first and second balancing valves are smaller than the apertures of the first, second, and third shut-off valves.

In some embodiments, the first shut-off valve, the second shut-off valve, and the third shut-off valve are driven by high-pressure hydraulic oil or compressed gas.

Second aspect

The invention constructs a gas turbine fuel leakage detection method, which is applied to the gas turbine fuel leakage detection system in any embodiment, and comprises the following steps:

a first leak detection step: the first cut-off valve, the second cut-off valve and the third cut-off valve are immediately cut off after the unit brake-off rotating speed is less than 3000rpm, when the gas turbine rotating speed is reduced to 700rpm, the first discharge valve and the second discharge valve are closed, the first balance valve is opened for pressurizing, the first balance valve is closed after the working pressure P1 of the fuel system is reached, the pressure of the first pressure sensor is continuously monitored, if the pressure of the first pressure sensor is unchanged during the test, the first cut-off valve, the second cut-off valve and the first discharge valve are not leaked, a second leak detection step is carried out, and if the pressure of the first pressure sensor is changed, a purging step during the unit start-up period is required to be restored during the unit start-up period;

And a second leak detection step: and when the combustible gas detection device detects no combustible gas, the second discharge valve is closed, the fuel system is boosted to positive pressure test pressure P2, then the first control valve, the second control valve, the third control valve and the fourth control valve are closed, the continuous monitoring of the combustible gas detection device is started, if the combustible gas detection device does not have an alarm, the purging operation is not needed, and if the combustible gas detection device has an alarm, the purging step during the starting period of the unit needs to be restored.

In some embodiments, further comprising:

Third leak detection step: and during the period from the start of the low-speed jigger to the restart of the high-speed jigger, keeping the first cut-off valve, the second cut-off valve, the third cut-off valve, the first balance valve and the second balance valve closed, opening the first control valve, the second control valve, the third control valve and the fourth control valve to be filled with compressed gas, opening the second discharge valve to replace fuel, closing the second discharge valve when the combustible gas detection device detects that no combustible gas exists, boosting the fuel system to a positive pressure test pressure P2, then closing the first control valve, the second control valve, the third control valve and the fourth control valve, opening continuous monitoring of the combustible gas detection device, and ensuring that the working pressure P1 of the fuel system is larger than the positive pressure test pressure P2.

In some embodiments, further comprising:

And if the first leakage detecting step, the second leakage detecting step and the third leakage detecting step detect abnormality, recovering a purging step during the starting period of the unit, if the first leakage detecting step, the second leakage detecting step and the third leakage detecting step detect no abnormality, canceling the purging step during the starting period of the unit, and then opening a second balance valve to ignite the downstream pressurized gas turbine of the second cut-off valve.

The implementation of the invention has the following beneficial effects: by using the gas turbine fuel leakage detection system and the gas turbine fuel leakage detection method, the purging step can be omitted under the condition of ensuring no gas leakage by detecting the tightness of the related valves, the starting time is reduced, the response speed of the gas turbine is improved, and the energy consumption is reduced.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the following description will be given with reference to the accompanying drawings and examples, it being understood that the following drawings only illustrate some examples of the present invention and should not be construed as limiting the scope, and that other related drawings can be obtained from these drawings by those skilled in the art without the inventive effort. In the accompanying drawings:

FIG. 1 is a schematic diagram of a gas turbine fuel leak detection system in accordance with certain embodiments of the invention;

FIG. 2 is a schematic illustration of a gas turbine combustion gas detection zone in some embodiments of the invention;

FIG. 3 is a logic diagram of a gas turbine fuel purge determination in some embodiments of the invention.

Detailed Description

For a clearer understanding of technical features, objects and effects of the present invention, a detailed description of embodiments of the present invention will be made with reference to the accompanying drawings. In the following description, it should be understood that the directions or positional relationships indicated by "front", "rear", "upper", "lower", "left", "right", "longitudinal", "transverse", "vertical", "horizontal", "top", "bottom", "inner", "outer", "head", "tail", etc. are configured and operated in specific directions based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention, and do not indicate that the apparatus or element to be referred to must have specific directions, and thus should not be construed as limiting the present invention.

It should also be noted that unless explicitly stated or limited otherwise, terms such as "mounted," "connected," "secured," "disposed," and the like are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. When an element is referred to as being "on" or "under" another element, it can be "directly" or "indirectly" on the other element or one or more intervening elements may also be present. The terms "first," "second," "third," and the like are used merely for convenience in describing the present invention and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, whereby features defining "first," "second," "third," etc. may explicitly or implicitly include one or more such features. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the following description, for purposes of explanation and not limitation, specific details are set forth such as the particular system architecture, techniques, etc., in order to provide a thorough understanding of the embodiments of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

Referring to FIG. 1, the present invention illustrates a gas turbine fuel leak detection system that includes a main fuel supply line 10, a first balance line 20, a second balance line 30, and a plenum line 40.

The fuel supply main pipe 10 is sequentially provided with a first cut-off valve 11, a second cut-off valve 12 and a third cut-off valve 13, and the first cut-off valve 11, the second cut-off valve 12 and the third cut-off valve 13 are arranged in series;

A first discharge pipe 50 is connected between the first shut-off valve 11 and the second shut-off valve 12, and a first discharge valve 51 is arranged on the first discharge pipe 50, and the number of the first discharge valves 51 can be one or a plurality of; a second discharge pipe 60 is provided between the second shut-off valve 12 and the third shut-off valve 13, and a second discharge valve 61 is provided on the second discharge pipe 60, and the number of the second discharge valves 61 may be one or more.

A first pressure sensor 14 is further provided between the first shut-off valve 11 and the second shut-off valve 12, a second pressure sensor 15 and a combustible gas detection device 16 are further provided between the first shut-off valve 11 and the third shut-off valve 13, and a differential pressure sensor 17 is connected to the inlet and outlet ends of the second shut-off valve 12. The number of the first pressure sensors 14 may be one or more, and the number of the second pressure sensors 15 may be one or more. The system is provided with a first pressure sensor 14 and a second pressure sensor 15 for continuously monitoring the pressure in both spaces. A differential pressure sensor 17 is provided to continuously monitor tightness of the second shut-off valve 12 during the leak detection phase, while a combustible gas detection device 16 is provided between the second shut-off valve 12 and the third shut-off valve 13 to continuously monitor whether the shut-off valve (mainly the second shut-off valve 12) has a leak. The combustible gas detection device 16 is optionally a combustible gas detector.

The two ends of the first balance pipe 20 are connected with the inlet and outlet ends of the first cut-off valve 11, and the first balance pipe 20 is provided with a first balance valve 21; the two ends of the second balancing pipe 30 are respectively connected to the inlet end of the first cut-off valve 11 and the outlet end of the second cut-off valve 12, and the second balancing pipe 30 is provided with a second balancing valve 31.

The first end of the pressurizing pipe 40 is connected to a gas source, such as a compressed air source or an inert gas source, the second end of the pressurizing pipe 40 is connected between the second shut-off valve 12 and the third shut-off valve 13, and the pressurizing pipe 40 is provided with a first control valve 41, a second control valve 42, a third control valve 43, a check valve 44 and a fourth control valve 45 from the first end to the second end thereof.

In some embodiments, the apertures of the first and second balance valves 21, 31 are smaller than the apertures of the first, second and third shut-off valves 11, 12, 13.

The first shut-off valve 11, the second shut-off valve 12, and the third shut-off valve 13 are driven by high-pressure hydraulic oil or compressed gas. The first cut-off valve 11, the second cut-off valve 12 and the third cut-off valve 13 are large-caliber cut-off valves, the driving device is hydraulic oil or compressed gas, the caliber of the large-caliber cut-off valves is high in flow capacity, and the vibration of the fuel pipeline is large in the switching process. The valve characteristics of the first shut-off valve 11, the second shut-off valve 12, and the third shut-off valve 13 are such that they can be opened and closed quickly to supply and shut off fuel quickly.

The first balance valve 21 and the second balance valve 31 are bypass balance valves, the valve apertures are small, only the pressure before and after the pressurization and balance cut-off valves are arranged, the arrangement of the first balance valve 21 and the second balance valve 31 can avoid pipeline vibration and pressure fluctuation caused by the large-aperture valve switches of the first cut-off valve 11, the second cut-off valve 12, the third cut-off valve 13 and the like, and the service lives of the first cut-off valve 11, the second cut-off valve 12 and the third cut-off valve 13 can be prolonged. Preferably, the first and second balancing valves 21, 31 are automatically controlled balancing valves, including but not limited to solenoid valves.

Further, the first and second discharge valves 51, 61 are provided mainly for discharge and replacement of fuel.

In some embodiments, a third discharge conduit 70 is further disposed between the second control valve 42 and the third control valve 43, and a third discharge valve 71 is disposed on the third discharge conduit 70.

In some embodiments, a drain pipe 80 is further disposed between the second control valve 42 and the third control valve 43, and a first drain valve 81 and a second drain valve 82 are disposed on the drain pipe 80.

In some embodiments, the second control valve 42 and the third control valve 43 are automatic control valves, which can be automatically controlled according to the rotation speed of the gas turbine, the second control valve 42 and the third control valve 43 can be wired or wireless connected with an upper computer of the gas turbine, and the second control valve 42 and the third control valve 43 can optionally comprise electromagnetic valves, but are not limited to electromagnetic valves.

In some embodiments, the first control valve 41 and the fourth control valve 45 are manual valves, and of course, the first control valve 41 and the fourth control valve 45 may also be automatic valves, including but not limited to solenoid valves.

In some embodiments, the check valve 44 is a one-way check valve that prevents gas from being blown into the pressurized conduit 40 to cause an explosion.

In some embodiments, the gas turbine fuel leak detection system further includes an upper computer that is connectable to the first shut-off valve 11, the second shut-off valve 12, the third shut-off valve 13, the first bleed valve 51, the second bleed valve 61, the first balancing valve 21, the second balancing valve 31, the first control valve 41, the second control valve 42, the third control valve 43, the check valve 44, the fourth control valve 45, the third bleed valve 71, the first drain valve 81, the second drain valve 82, the first pressure sensor 14, the second pressure sensor 15, the combustible gas detection device 16, and the differential pressure sensor 17, and that can be either a wired connection or a wireless communication connection for receiving process-related monitoring data and transmitting related control instructions, which can include valve opening or closing instructions, and can also adjust the opening of the valves.

The gas turbine fuel leakage detection system is applied as follows:

In the system, at the moment of opening the gas turbine, valves such as the first cut-off valve 11, the second cut-off valve 12, the third cut-off valve 13, the first balance valve 21, the second balance valve 31 and the like are closed, and the first discharge valve 51 and the second discharge valve 61 are opened to discharge the pressure relief of the combustible gas. The first control valve 41, the second control valve 42, the third control valve 43, the check valve 44, the fourth control valve 45, etc. are kept in a closed state, i.e., the charging pipe 40 is kept in a closed state. Before the machine set is switched on to the starting ignition of the gas turbine, the following leakage checking steps are carried out:

1) And (5) tightness self-checking of the valve. The degree of valve leakage of the first shut-off valve 11, the second shut-off valve 12, the third shut-off valve 13 is determined by monitoring the pipe chamber between the first shut-off valve 11, the second shut-off valve 12, the third shut-off valve 13. The valve self-checking is divided into two stages after stopping and before starting. After stopping, the self-check is that after the fuel valve is discharged, a valve self-check program is executed, after the rotating speed is lower than 700rpm, the first cut-off valve 11, the second cut-off valve 12, the third cut-off valve 13 and the first discharge valve 51 are kept closed, the first balance valve 21 is opened for pressurization, after the test pressure is reached, the first balance valve 21 is closed, the pressure of the first pressure sensor 14 is continuously monitored, and the pressure is unchanged during the test to be qualified for valve leak detection.

2) The tube replacement partial replacement and the flammable gas detection device 16 continue to leak. The leak detection time is the time when the valve tightness self-check is completed, the first shutoff valve 11, the second shutoff valve 12, the third shutoff valve 13, the first balance valve 21, and the second balance valve 31 are kept closed, the compressed gas supply valves such as the first control valve 41, the second control valve 42, the third control valve 43, the check valve 44, and the fourth control valve 45 are opened, the second discharge valve 61 is kept opened, and the space formed by the second shutoff valve 12, the third shutoff valve 13, and the second discharge valve 61 is replaced, and the mark of the replacement qualification is that the combustible gas is not detected by the combustible gas detection device 16. After the replacement is qualified, the second discharge valve 61 is closed, the pipeline test pressure is pressurized, continuous monitoring of the combustible gas detection device 16 is started, and no alarm is given to the combustible gas detection device 16, so that the condition is qualified.

3) The pressurized conduit 40 is positively pressurized to leak test the pressure below the conduit fuel operating pressure. The gas turbine fuel leak detection system starts after the pipeline replacement is qualified and is boosted to the test pressure, and ends after the machine is started, and the valve pressure difference of the second cut-off valve 12 is continuously monitored during the starting time. The first shutoff valve 11, the second shutoff valve 12, the third shutoff valve 13, the first discharge valve 51, and the second discharge valve 61 are kept closed, the first control valve 41, the second control valve 42, the third control valve 43, the check valve 44, and the fourth control valve 45 are kept open, and the compressed gas supply valves are kept open, and the charging pressure is the natural gas working pressure of the gas turbine, and the changes in the differential pressure of the differential pressure sensors 17 of the respective valve states and the second shutoff valve 12 are continuously monitored, and the internal leakage of the valves is indicated when the differential pressure changes.

Processing of anomalies during leak detection:

In the above three leak detection stages, whether the valve states, pressures, differential pressures, the flammable gas detection device 16, etc. are in the normal state is continuously monitored, and once any abnormal event (abnormal event) occurs, if the pressure parameter of the first pressure sensor 14 is changed greatly, the pressure parameter of the second pressure sensor 15 is changed greatly, etc., it may not be possible to completely ensure that the fuel is not leaked. The system (such as an upper computer) is provided with logic judgment, if the tightness of the valve is self-checked qualified in the monitoring process, the combustible gas detection device 16 continuously checks leakage qualified and the positive pressure leakage detection of the external gas pressurizing pipeline is met, the purging time is canceled, if the monitoring is abnormal, the purging in the starting stage is restored, the logic control diagram is shown in fig. 3, fig. 3 is a leakage detection result judgment diagram of the fuel leakage detection system of the gas turbine, all the input conditions are in a relation with each other, and the failure of any condition can lead to failure of the leakage detection result. And if the leak detection result is qualified, canceling the purging step during the starting period of 10 minutes, and if the leak detection result is output as unqualified, continuing the gas purging procedure.

In some embodiments, the invention also discloses a gas turbine fuel leak detection method, which can be applied to the gas turbine fuel leak detection system according to any one of the embodiments, and is shown in fig. 2, wherein fig. 2 is an operation interval and a mode of the whole gas turbine fuel leak detection system from loading to stopping to restarting, and the main nodes are organically switched on, the rotating speed is 700rpm, and the gas turbine fuel leak detection system is in a leak detection stage, such as low-speed turning, high-speed turning, purging starting, purging ending, ignition, speed rising and grid connection. By the method for detecting the leakage of the fuel of the gas turbine, the purging step before starting and igniting the gas turbine can be omitted, the starting time is shortened, the purging energy consumption is reduced, and the time from starting to grid connection of the gas turbine is shortened by about one third.

In some embodiments, the gas turbine fuel leak detection method may include the steps of:

A first leak detection step: the first cut-off valve 11, the second cut-off valve 12 and the third cut-off valve 13 are immediately cut off after the unit brake-off rotating speed is less than 3000rpm, when the gas turbine rotating speed is reduced to 700rpm, the first discharge valve 51 and the second discharge valve 61 are closed, the first balance valve 21 is opened for pressurization, the first balance valve 21 is closed after the working pressure P1 (such as 3-5 Mpa) of the fuel system is reached, the pressure of the first pressure sensor 14 is continuously monitored, if the pressure of the first pressure sensor 14 is unchanged during the test, the first cut-off valve 11, the second cut-off valve 12 and the first discharge valve 51 are not leaked, and a second leak detection step is entered, such as the pressure of the first pressure sensor 14 is changed, and a purging step during the unit start-up period needs to be restored during the unit start-up period;

And a second leak detection step: during the period from the start of the low-speed turning to the restart of the high-speed turning, after the low-speed turning is put into operation, the first cut-off valve 11, the second cut-off valve 12, the third cut-off valve 13, the first balance valve 21 and the second balance valve 31 are kept closed, the first control valve 41, the second control valve 42, the third control valve 43 and the fourth control valve 45 are opened, compressed gas is introduced, the second discharge valve 61 is opened for fuel replacement, when the combustible gas detection device 16 detects no combustible gas, the second discharge valve 61 is closed, the fuel system is boosted to a positive pressure test pressure P2 (about 0.1 Mpa), then the first control valve 41, the second control valve 42, the third control valve 43 and the fourth control valve 45 are closed, and the continuous monitoring of the combustible gas detection device 16 is started, if the combustible gas detection device 16 does not have an alarm, and if the combustible gas detection device 16 has an alarm, the purging step during the start-up of the unit needs to be resumed.

Further, the gas turbine fuel leak detection method may further include:

Third leak detection step: during the period from the start of the low-speed turning to the restart of the high-speed turning, the first cut-off valve 11, the second cut-off valve 12, the third cut-off valve 13, the first balance valve 21 and the second balance valve 31 are kept closed, the first control valve 41, the second control valve 42, the third control valve 43 and the fourth control valve 45 are opened to allow compressed gas to be introduced, the second discharge valve 61 is opened to perform fuel replacement, when the combustible gas detection device 16 detects that no combustible gas exists, the second discharge valve 61 is closed, the fuel system is boosted to the positive pressure test pressure P2, then the first control valve 41, the second control valve 42, the third control valve 43 and the fourth control valve 45 are closed, the continuous monitoring of the combustible gas detection device 16 is started, the fuel system working pressure P1 is larger than the positive pressure test pressure P2, when the second cut-off valve 12 is closed, the combustible gas detection device 16 alarms or the pressure of the second pressure sensor 15 is abnormally increased, and the purging step during the starting period is resumed.

Further, the gas turbine fuel leak detection method may further include:

The rotational speed reaches the high-speed jigger rotational speed after the gas turbine is started, if the first leak detection step, the second leak detection step and the third leak detection step detect abnormality, the purging step during the start of the unit is resumed, if the first leak detection step, the second leak detection step and the third leak detection step detect no abnormality, the purging step during the start of the unit is canceled, and then the second balance valve 31 is opened to ignite the gas turbine after the downstream pressurization of the second shut-off valve 12.

Specifically, referring to fig. 2, the operating interval of the gas turbine fuel leak detection system is that after the gas turbine is switched on, the rotation speed is rapidly reduced from 3000rpm, when the rotation speed is lower than 700rpm, the fuel leak detection system starts to operate, and continuously operates during the period of low-speed turning, and the unit is restarted to start to the high-speed turning rotation speed as a leak detection end point (the dotted line stage in fig. 2). The system acts as follows during the period from 3000rpm to 700rpm restart:

1) The state of the on-load running valve of the unit is as follows: the first shut-off valve 11, the second shut-off valve 12 and the third shut-off valve 13 are kept in a fully opened state, and other valves in the system are all in a closed state, so that the first pressure sensor 14, the second pressure sensor 15, the combustible gas detection device 16 and the differential pressure sensor 17 work normally.

2) 3000Rpm to 700rpm, solid line portion of fig. 2. When the unit receives a brake-off command, the first cut-off valve 11, the second cut-off valve 12 and the third cut-off valve 13 are immediately closed from the fully opened state, the first discharge valve 51 and the second discharge valve 61 are opened to discharge fuel, and the rest of valves are not operated. The valve group of the fuel flow pressure regulating system acts according to the set logic.

3) During the 700rpm to low speed jigger period, the valve tightness self-checking stage is the broken line section in fig. 2. After the rotation speed is lower than about 700rpm, the first discharge valve 51 and the second discharge valve 61 are closed, then the first balance valve 21 is opened for pressurization, the first balance valve 21 is closed after the fuel system working pressure P1 is reached, the pressure of the first pressure sensor 14 is continuously monitored, the tightness of the valve in the areas of the first cut-off valve 11, the second cut-off valve 12 and the first discharge valve 51 is continuously monitored, and no change of the pressure during the test is qualified for valve leak detection, so that no leakage of the first cut-off valve 11, the second cut-off valve 12 and the first discharge valve 51 is proved. I.e., the first leak detection step described above.

4) The positive pressure leak detection phase of the pressurized conduit 40 of fig. 2 begins during the period from when the low speed jigger begins to restart the high speed jigger. When the low-speed jigger is put into operation, the tightness self-checking flow of the valve in the previous stage is finished, and the valve leakage is judged in the previous stage, so that the valve leakage detection in the previous stage is not needed, and the purging step flow during the unit starting period is restored after the unit is started. If it is determined in the previous stage that the valve is not leaking, the valves such as the first control valve 41, the second control valve 42, the third control valve 43, the check valve 44, and the fourth control valve 45 are opened, compressed gas is introduced into the main fuel supply pipe 10 through the pressurizing pipe 40, the second discharge valve 61 is opened to perform fuel replacement, the second discharge valve 61 is closed when the combustible gas detection device 16 detects no combustible gas, the system is pressurized to a positive pressure test pressure P2 (micro positive pressure, hereinafter referred to as P2), and then the first control valve 41, the second control valve 42, the third control valve 43, the check valve 44, and the fourth control valve 45 are closed. I.e., the second leak detection step described above.

5) During the period from the start of the low speed turning to the restart of the high speed turning, the combustible gas detection means 16 in fig. 2 is in a leak detection phase. This step corresponds to the valve action of step 4) above, and the combustible gas monitoring prevents fuel leakage one more step. The upstream of the valve is the working pressure P1 in the tightness self-checking stage of the valve in the 3 rd step, the downstream pressure of the second shut-off valve 12 is the test pressure P2 filled in the pressurizing pipe 40, the working pressure P1 is greater than the test pressure P2, and when the second shut-off valve 12 is not tightly closed, the gas of the upstream working pressure leaks to the downstream of the second shut-off valve 12, and at this time, the flammable gas detection device 16 alarms or the pressure of the second pressure sensor 15 is abnormally increased. I.e., a third leak detection step.

6) The rotational speed reaches the high-speed jigger rotational speed after starting, and the leakage of the combustible gas is detected in the above three detection and leak detection steps, as shown in fig. 3, if any one detection is abnormal, the purging step in the starting period of the unit is resumed, if no leakage of fuel is detected, the purging is canceled, and the second balance valve 31 is opened to ignite the pressurized and post-combustion engine downstream of the second shut-off valve 12.

The gas turbine fuel leakage detection system and the gas turbine fuel leakage detection method have the following beneficial effects:

(1) The gas turbine response time is faster with the elimination of the 10-15 minute purge. The corresponding time from the current statute to the grid connection is reduced to 20 minutes, and the response time is shortened by 30 percent.

(2) The purging is canceled, so that the forced cooling of the waste heat boiler of the gas turbine in the high-speed turning stage is prevented, the forced cooling of the waste heat boiler brings about energy waste, the starting time of the gas turbine is prolonged, and the forced cooling of the waste heat boiler pipeline shortens the service life.

(3) In order to ensure that fuel is absolutely leak-free, the system arranges a first shut-off valve 11, a second shut-off valve 12, a third shut-off valve 13 in series, and two first and second discharge valves 51, 61 are provided, as well as a first pressure sensor 14, a second pressure sensor 15, a combustible gas detection device 16, a differential pressure sensor 17, etc., to ensure that no fuel is leaked by mutual authentication.

(4) Three means for detecting gas leakage (a first leakage detecting step, a second leakage detecting step and a third leakage detecting step), and no gas leakage is ensured by three different detecting means. The core of the valve leak detection stage is to ensure that the first cut-off valve 11 and the second cut-off valve 12 are free from leakage, the external pressurizing core of the pressurizing pipeline 40 is to ensure that the second cut-off valve 12 and the third cut-off valve 13 are free from leakage, and the core of the combustible gas monitoring is to ensure that the second cut-off valve 12 is free from leakage. These three means in fact make it impossible for the entire fuel system to leak as long as the second shut-off valve 12 in the middle is guaranteed to be leak-free.

(5) If the traditional detection device is arranged on the side of the waste heat boiler, the temperature is too high due to the fact that the space is too large, and the traditional detection device is not easy to install. There are few fuel lines on which a flammable gas concentration sensor is installed, because the lines are always filled with flammable gas, and installation is not significant. The system is provided with the combustible gas detection device 16 between the two second shut-off valves 12 and the third shut-off valve 13, gas in a narrow space is replaced in the period of monitoring the concentration of the combustible gas, the second shut-off valve 12, the third shut-off valve 13 and the second discharge valve 61 can be replaced in a small space within a few minutes, the operation is simple and convenient, and only one combustible gas detection device 16 is installed. If the second shut-off valve 12 leaks, the combustible gas concentration can be detected in real time.

(6) In the stage of monitoring the differential pressure of the second shut-off valve 12 by the external gas charging pressure, the differential pressure sensor 17 continuously monitors the differential pressure before and after the second shut-off valve 12, and the core of the system is that if the second shut-off valve 12 is tight, natural gas does not leak past even if the first shut-off valve 11 and the third shut-off valve 13 are not tight.

(7) The first and second balance valves 21 and 31 having small diameters are provided, and used as balance valves of the first and second shut-off valves 11 and 12, and are opened when the system needs to be pressurized, and the driving method thereof may be electromagnetic valves or pneumatic valves. The switching frequency of the large-caliber valve is reduced, the service lives of the large-caliber valves such as the first cut-off valve 11, the second cut-off valve 12 and the like are prolonged, and vibration and pressure fluctuation of a pipeline caused by frequent switching actions of the large-caliber valve are prevented.

It is to be understood that the above examples only represent preferred embodiments of the present invention, which are described in more detail and are not to be construed as limiting the scope of the invention; it should be noted that, for a person skilled in the art, the above technical features can be freely combined, and several variations and modifications can be made without departing from the scope of the invention; therefore, all changes and modifications that come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims (10)

1. A gas turbine fuel leak detection system, characterized by comprising a fuel supply main pipe (10), a first balance pipe (20), a second balance pipe (30) and a pressurizing pipe (40);

A first cut-off valve (11), a second cut-off valve (12) and a third cut-off valve (13) are sequentially arranged on the main fuel supply pipeline (10);

A first discharge pipeline (50) is connected between the first cut-off valve (11) and the second cut-off valve (12), and a first discharge valve (51) is arranged on the first discharge pipeline (50); a second discharge pipeline (60) is arranged between the second shut-off valve (12) and the third shut-off valve (13), and a second discharge valve (61) is arranged on the second discharge pipeline (60);

A first pressure sensor (14) is further arranged between the first cut-off valve (11) and the second cut-off valve (12), a second pressure sensor (15) and a combustible gas detection device (16) are further arranged between the first cut-off valve (11) and the third cut-off valve (13), and a pressure difference sensor (17) is connected to the inlet end and the outlet end of the second cut-off valve (12);

Two ends of the first balance pipeline (20) are connected to the inlet and outlet ends of the first cut-off valve (11), and a first balance valve (21) is arranged on the first balance pipeline (20); two ends of the second balance pipeline (30) are respectively connected with the inlet end of the first cut-off valve (11) and the outlet end of the second cut-off valve (12), and a second balance valve (31) is arranged on the second balance pipeline (30);

The second end of the pressurizing pipeline (40) is connected between the second shut-off valve (12) and the third shut-off valve (13), and the pressurizing pipeline (40) is sequentially provided with a first control valve (41), a second control valve (42), a third control valve (43), a check valve (44) and a fourth control valve (45) from the first end to the second end of the pressurizing pipeline.

2. The gas turbine fuel leak detection system as defined in claim 1, wherein a third discharge conduit (70) is further provided between the second control valve (42) and the third control valve (43), and a third discharge valve (71) is provided on the third discharge conduit (70).

3. The gas turbine fuel leak detection system as defined in claim 1, wherein a drain pipe (80) is further disposed between the second control valve (42) and the third control valve (43), and a first drain valve (81) and a second drain valve (82) are disposed on the drain pipe (80).

4. The gas turbine fuel leak detection system of claim 1, wherein the second control valve (42) and the third control valve (43) are automatic control valves.

5. The gas turbine fuel leak detection system of claim 1, wherein the first control valve (41) and the fourth control valve (45) are manual valves.

6. The gas turbine fuel leak detection system according to claim 1, wherein the caliber of the first balance valve (21), the second balance valve (31) is smaller than the caliber of the first shut-off valve (11), the second shut-off valve (12), the third shut-off valve (13).

7. The gas turbine fuel leak detection system according to claim 1, wherein the first shut-off valve (11), the second shut-off valve (12), and the third shut-off valve (13) are driven by high-pressure hydraulic oil or compressed gas.

8. A gas turbine fuel leak detection method for use in a gas turbine fuel leak detection system as defined in any one of claims 1 to 7, comprising the steps of:

A first leak detection step: the first shut-off valve (11), the second shut-off valve (12) and the third shut-off valve (13) are immediately shut off after the unit opening rotation speed is less than 3000rpm, when the gas turbine rotation speed is reduced to 700rpm, the first discharge valve (51) and the second discharge valve (61) are closed, the first balance valve (21) is opened to be pressurized, the first balance valve (21) is closed after the fuel system working pressure P1 is reached, the pressure of the first pressure sensor (14) is continuously monitored, if the pressure of the first pressure sensor (14) is unchanged during the test, the first shut-off valve (11), the second shut-off valve (12) and the first discharge valve (51) are not leaked, and a second leak detection step is carried out, if the pressure of the first pressure sensor (14) is changed, a purging step during the unit start-up needs to be restored;

And a second leak detection step: during the period from the start of low-speed turning to the restart of high-speed turning, after the low-speed turning is put into operation, the first cut-off valve (11), the second cut-off valve (12), the third cut-off valve (13), the first balance valve (21) and the second balance valve (31) are kept closed, the first control valve (41), the second control valve (42), the third control valve (43) and the fourth control valve (45) are opened, compressed gas is introduced, the second discharge valve (61) is opened for fuel replacement, when the combustible gas detection device (16) detects no combustible gas, the second discharge valve (61) is closed, the fuel system is boosted to positive pressure test pressure P2, then the first control valve (41), the second control valve (42), the third control valve (43) and the fourth control valve (45) are closed, the continuous monitoring of the combustible gas detection device (16) is started, if the combustible gas detection device (16) does not have alarm, no need to perform purging operation, and if the combustible gas detection device (16) has alarm, purging steps of a machine set are required to be restored during the startup period.

9. The gas turbine fuel leak detection method as defined in claim 8, further comprising:

Third leak detection step: during the period from the start of low-speed turning to the restart of high-speed turning, the first shut-off valve (11), the second shut-off valve (12), the third shut-off valve (13), the first balance valve (21) and the second balance valve (31) are kept closed, the first control valve (41), the second control valve (42), the third control valve (43) and the fourth control valve (45) are opened, compressed gas is introduced, the second discharge valve (61) is opened for fuel replacement, when the combustible gas detection device (16) detects no combustible gas, the second discharge valve (61) is closed, the fuel system is boosted to a positive pressure test pressure P2, then the first control valve (41), the second control valve (42), the third control valve (43) and the fourth control valve (45) are closed, the continuous monitoring of the combustible gas detection device (16) is started, the working pressure P1 of the fuel system is larger than the positive pressure test pressure P2, when the second shut-off valve (12) is closed, the fuel gas at the working pressure upstream of the second shut-off valve (12) is not leaked to the second shut-off valve (12), and the abnormal pressure detection device (15) is restored during the abnormal pressure recovery period of the second pressure detection device (15).

10. The gas turbine fuel leak detection method as defined in claim 9, further comprising:

And if the first leakage detecting step, the second leakage detecting step and the third leakage detecting step detect abnormality, recovering a purging step during the starting period of the unit, if the first leakage detecting step, the second leakage detecting step and the third leakage detecting step detect no abnormality, canceling the purging step during the starting period of the unit, and then opening a second balance valve (31) to ignite the gas turbine after the downstream pressure of the second cut-off valve (12).