A gas turbine elastic purge device and elastic purge method

Abstract

The present invention relates to the field of gas turbine control, and more particularly to a gas turbine elastic purge device and an elastic purge method. The present invention adds a combustible gas detector group in the exhaust section of the gas turbine and the waste heat boiler, respectively, and by adding an elastic purge function, the startup mode can be selected by detecting the presence of combustible gas in the exhaust section of the gas turbine and the waste heat boiler. Through the method of the present invention, the gas turbine startup purge in the prior art can be changed to an elastic purge, which can greatly improve the peak load response efficiency and economy of the unit.

Description

Technical Field

[0001] The invention relates to the field of gas turbine control, and in particular to a gas turbine elastic purge device and an elastic purge method. Background Art

[0002] In the prior art, combustibles may accumulate in the gas turbine exhaust duct and waste heat boiler. There are many sources of combustibles depending on the type and characteristics of the fuel. For units using gas fuel, combustible gas may come from the leakage of gas fuel during the unit standby period, or from residual fuel due to incomplete combustion before shutdown. For units using liquid fuel, incomplete combustion will leave liquid fuel, intermediate combustible gas (such as CO, etc.) or carbon powder attached to the inner surface of the downstream flow channel of the gas turbine. These liquid fuels will form volatile combustible mist on the inner surface. When the temperature in the flue reaches the auto-ignition point, or the temperature is above the flash point and there is an igniter, the combustible mist will explode and damage the equipment. In order to ensure the safety of the downstream flow channel of the gas turbine and the waste heat boiler, and to avoid the accumulation of combustibles in the downstream flow channel of the gas turbine, domestic power plants generally stipulate that air purging before startup is a necessary safety measure.

[0003] Chinese patent CN113513409A discloses a purge system for a gas turbine and a control method thereof, wherein the purge system for a gas turbine has a burner, and the purge system for a gas turbine includes: a fuel branch, an air source component, and a control component. There are multiple fuel branches, and the multiple fuel branches are connected to the burner. The air source component is connected to the multiple fuel branches. The air source component is used to output inert gas to the multiple fuel branches to purge the fuel branches before the burner supplies fuel and after the fuel is withdrawn. The control component is connected to the air source component and the fuel branch, and the control component is used to control the air source component to purge the fuel branch. This solution has high safety performance for the purge system of the gas turbine and is conducive to improving the stability of gas turbine combustion, but it cannot achieve elastic purge.

[0004] Although gas turbine models vary, the time required for gas turbine purge is specified:

[0005] According to international standards, the gas turbine, waste heat boiler (and other exhaust systems (such as bypass chimneys) are purged before the unit is started and operated. This purge is at least five times the volume replacement. At present, the typical purge time of the gas turbine ranges from 5 minutes to 18 minutes. Reducing the purge time can significantly shorten the start-up and grid-connection time of the gas turbine. At the same time, it reduces the consumption of plant electricity by high-speed cranking purge, especially for peak-shaving units that start and stop daily, and the energy-saving benefits are more prominent.

[0006] According to domestic gas turbine standards, the starting control system should provide sufficient time for automatic purge of the gas turbine to ensure the safe operation of the gas turbine and downstream components. Unless otherwise specified by the state, the purge cycle should generally purge at least the entire exhaust system space (including the chimney) before the unit is ignited. However, this may not be necessary when there are alternative preventive measures.

[0007] Gas turbine ignition process: After the unit issues a normal start-up command, the igniter is pushed into the working position, the pressure control valves of the main fuel and the duty fuel are opened to the set opening, and the static frequency converter is maintained to drive the unit to increase the speed to the high disk speed. The unit maintains the high disk speed to purge the gas turbine exhaust channel. The purge time starts from the speed of 700rpm. After the timing ends, the gas turbine begins to slow down to the ignition speed of about 500rpm. The gas turbine igniter is energized to start ignition. At the same time, the control oil system tripping solenoid valve is closed to establish a safety oil pressure. After the safety oil pressure is normal, the relevant valves of the natural gas supply system are opened. If a flame is detected from the time the fuel is put into use, it is judged that the ignition is successful.

[0008] The purpose of purging is to ensure that there is no accumulation of combustible gas in the downstream exhaust flow passage when the gas turbine is started and ignited, so as to avoid explosion accidents. The third volume of the national standard for gas turbines makes recommendations on the necessity of gas turbine purging, but only requires the purge volume to be three times the volume, which is relatively less than the five times of the international standard. This may not be necessary when there are alternative preventive measures. The gas turbine is also considered to be purged during the period from startup to ignition. This parameter is not counted in the purge time of the gas turbine. Before using intuitive equipment for online monitoring, operators directly calculated the ignition time of three times the volume of the machine room or a shorter time.

[0009] However, the uncertainty factor in this measure is too large. Although reducing the purge time can better play the role of the peak-shaving unit, there is no effective internal situation monitoring plan, which makes the operation a blind selection process. For example, if there is internal combustible gas but there is not enough purge time, once an accident occurs, it will cause great losses.

[0010] Therefore, a new gas turbine elastic purge device and elastic purge method are needed to solve the problems existing in the prior art. Summary of the invention

[0011] In view of this, the present invention provides a gas turbine elastic purge device and an elastic purge method, which can greatly improve the peak-shaving response efficiency and economy of the unit.

[0012] The technical solution of the present invention is:

[0013] A gas turbine elastic purge device, characterized in that it comprises a gas turbine exhaust section, a waste heat boiler, and a control module;

[0014] The gas turbine exhaust section comprises a gas turbine body, an exhaust section, and a diffuser section connected in sequence, and a first combustible gas detector group is arranged in the exhaust section;

[0015] The waste heat boiler comprises a boiler body and a chimney which are connected to each other, and a second combustible gas detector group is arranged in the boiler body;

[0016] The pressure diffuser section is connected to the boiler body;

[0017] The control module is connected to the combustion engine body, the first combustible gas detector group, and the second combustible gas detector group respectively.

[0018] Furthermore, the first combustible gas detector group includes at least three first combustible gas detectors, which are respectively arranged at 10 o'clock, 12 o'clock and 2 o'clock in the exhaust section along the axial exhaust direction. In the present invention, three measuring points are taken at the tail of the cylindrical exhaust section connected between the gas turbine exhaust cylinder and the boiler diffusion section. Along the axial flow direction of the gas, the sampling holes are opened at 10 o'clock, 12 o'clock and 2 o'clock. The perforations are welded on the outside of the flange clamping structure, and the internal mechanical seal is not welded to prevent the metal from breaking due to stress.

[0019] Furthermore, a high-pressure area, a medium-pressure area, and a low-pressure area are sequentially provided in the boiler body, and at least two heating modules are respectively provided in the high-pressure area, the medium-pressure area, and the low-pressure area. The heating modules are connected in sequence, and a partition is provided at the top between adjacent heating modules or at the top between the heating module and the chimney, and a second combustible gas detector group is provided in the partition; the second combustible gas detector group includes at least six second combustible gas detectors, and the second combustible gas detectors in adjacent partitions are symmetrically arranged on the left and right.

[0020] Particularly, the number of the second combustible gas detectors of the present invention is arranged correspondingly according to the heating modules arranged in the high-pressure area, the medium-pressure area, and the low-pressure area.

[0021] Preferably, the boiler body of the present invention is implemented by using existing technology. The heating modules in the boiler are arranged with tube panels, all of which are finned tubes, for heating steam. A spacer is provided between the top of each heating module and the adjacent heating modules. Through extensive research by the applicant, it is found that as a geometric structure point, the possibility of combustible gas accumulation is high. This is a location where combustible gas is easily accumulated, which the applicant has obtained through a large number of creative experiments.

[0022] In one embodiment of the present invention, the second combustible gas detector group includes six second combustible gas detectors, which are respectively arranged in the interval at the top of the heating module in the boiler body and the interval at the top between the heating module and the chimney. The boiler body has a total of six heating modules, and two heating modules are respectively provided in the high-pressure area, the medium-pressure area, and the low-pressure area. They are arranged along the exhaust axis and are sequentially provided with a first interval, a second interval, a third interval, a fourth interval, a fifth interval, and a sixth interval. The second combustible gas detectors in the first interval, the third interval, and the fifth interval are arranged on the left; the second combustible gas detectors in the second interval, the fourth interval, and the sixth interval are arranged on the right.

[0023] In the present invention, a geometric structure is provided in the middle of each heating module as a partition, and an inspection window is provided at the top of the partition. The sampling measuring point is located next to the inspection window for easy installation and maintenance. The sampling tube is extended to a distance of 10 cm and a second combustible gas detector is provided. Preferably, the second combustible gas detector is provided with a filtering structure.

[0024] Furthermore, the control module is provided with a two-out-of-three redundant voting program, and the signals of the two-out-of-three redundant voting program are respectively taken from the first combustible gas detector group and the second combustible gas detector group. In the present invention, the two-out-of-three redundant voting program adopted is the prior art, which is to transmit the signal output by the combustible gas detector group on site to the control module. When only one detector alarms, no action signal will be sent to the gas turbine unit control system. Only when two or more detectors alarm at the same time, an action signal will be sent to the gas turbine unit control system.

[0025] Further, the control module includes an elastic purge control program, and the elastic purge control program setting includes:

[0026] When the gas alarm concentration is between 1-5%LEL, the purge time will be three times the volume;

[0027] When the gas alarm concentration is between 6-25%LEL, the purge time will be five times the volume;

[0028] If the gas alarm concentration value is 0, it will directly enter the start state or manually choose whether to extend the purge time;

[0029] When the gas alarm concentration is greater than 25% LEL, check the fuel system of the gas turbine.

[0030] Preferably, the first combustible gas detector group can also be arranged at a place where the combustible gas can be easily detected according to the exhaust flow channel structure of the exhaust section, the characteristics of the combustible gas and the airflow direction.

[0031] Preferably, the combustible gas detector adopts a pump-suction detector. Before starting the machine, the gas in the exhaust flow channel is detected and analyzed, and the gas in the detection area is sent to the detector for detection in the form of extraction sampling. After the detector detects the concentration signal of the combustible gas, it sends out a configuration signal. If the concentration value is lower than the alarm value, the control system allows the start-up command to be sent directly.

[0032] The present invention also provides a gas turbine elastic purging method, characterized in that it includes the above-mentioned gas turbine elastic purging device, including the following:

[0033] Add the first combustible gas detector group in the exhaust section of the gas turbine to monitor the combustible gas status in the exhaust section of the gas turbine;

[0034] Add a second combustible gas detector group to the waste heat boiler to monitor the combustible gas status of the waste heat boiler;

[0035] An elastic purge program is added to the control module to realize automatic elastic purge of the gas turbine.

[0036] The method of the present invention can effectively reduce the purge time by five times the volume. Purge is performed only when the combustible gas detector detects the combustible gas concentration, and no purge is performed when the combustible gas concentration is not detected.

[0037] Furthermore, the present invention also includes, before starting the engine, detecting the combustible gas concentration of the gas turbine exhaust section and the waste heat boiler; the gas alarm concentration value is set to two alarms, and the purge procedure is divided into three levels; wherein, the first-level gas alarm concentration is set at 5%LEL, the purge time is set to three times the volume time, the second-level gas alarm concentration is set at 25%LEL, the purge time is set to five times the volume time, the third-level gas alarm concentration value is 0, directly entering the startup state or manually selecting whether to extend the purge time.

[0038] In the present invention, the combustible gas detector group transmits the detection data to the unit control system after detecting the gas in the space, and incorporates this data into the pre-start purge logic to achieve flexible purge, allowing the unit to select a preset purge time according to the combustible gas concentration value before starting. This approach not only ensures safety, but also can be used to monitor the working condition of the fuel system valve group and the completeness of combustion.

[0039] Furthermore, the present invention also includes determining that the combustible gas concentration detection program is executed for a long time, detecting the combustible gas concentration in the exhaust section of the gas turbine and the waste heat boiler after shutdown, and determining whether there is no combustible gas in the exhaust section of the gas turbine and the waste heat boiler before starting.

[0040] Furthermore, the present invention also includes detecting the combustible gas concentration during shutdown, setting two alarm levels for the gas alarm concentration value, and when the concentration of two or more deep detectors in the combustible gas detector group is higher than the lower explosion limit, operating according to the actual situation: when the gas alarm concentration is 1-5%LEL, entering the three-fold volume purge time; when the gas alarm concentration is 6-25%LEL, entering the five-fold purge volume time; when the gas alarm concentration value is 0, directly entering the startup state or manually selecting whether to extend the purge time; when the gas alarm concentration is greater than 25%LEL, the fuel system of the gas turbine is checked.

[0041] The present invention also provides another gas turbine elastic purging method, characterized in that it includes the above-mentioned gas turbine elastic purging device, and includes the following steps:

[0042] A. When shutting down, detect the combustible gas concentration in the exhaust section of the gas turbine, and set the gas alarm concentration value to two alarm levels;

[0043] B. Detect the combustible gas concentration of the waste heat boiler during shutdown, and set the gas alarm concentration value to two alarm levels;

[0044] C. When the concentration of two or more deep detectors in the combustible gas detector group is higher than a certain lower explosion limit output signal; perform the following operations: when the gas alarm concentration is 1-5%LEL, enter the three-fold volume purge time; when the gas alarm concentration is 6-25%LEL, enter the five-fold volume purge time; when the gas alarm concentration is greater than 25%LEL, check the fuel system of the gas turbine;

[0045] D. When the gas alarm concentration value is 0, it will directly enter the start state or allow the operator to choose whether to extend the purge time.

[0046] Furthermore, in step A, the combustible gas concentration in the exhaust section of the gas turbine is set to two alarm stages, the first stage is set to 5%LEL, and the second stage is set to 25%LEL; in step B, the combustible gas concentration in the waste heat boiler is set to two alarm stages, the first stage is set to 5%LEL, and the second stage is set to 25%LEL; in step C, the gas concentration data of the combustible gas detector is extracted, and the control module determines whether to send an elastic purge signal to the gas turbine through the signal obtained by the three-out-of-two redundant voting procedure.

[0047] Furthermore, purging is performed only when the combustible gas detector detects the combustible gas concentration, and no purging is performed when the combustible gas concentration is not detected.

[0048] In the present invention, combustible gas detector groups are added to the exhaust section of the gas turbine and the waste heat boiler to monitor the combustible gas in the exhaust flow channel of the gas turbine, and the combustible gas detector signal is controlled through a three-out-of-two redundant voting program. The gas concentration data is extracted through the control module and it is determined whether to send an elastic purge signal. The device and method of the present invention can effectively reduce the startup time of the gas unit and greatly improve the peak load response efficiency and economy of the unit.

[0049] When the combustible gas detector group does not detect gas concentration in the exhaust flow space of the gas turbine, the startup purge can be canceled. After the startup purge is canceled, the grid-connected load time of the gas turbine can be reduced by up to 14 minutes by calculating the volume of the exhaust flow space minus the volume flow during purge. At the same time, the heat loss of the purge airflow to the boiler economizer is reduced, which can reduce the grid-connected load time of the steam turbine boiler in hot and warm states.

[0050] During the purge, three to five times the volume of ambient cold air from the engine to the boiler enters, which reduces the metal temperature, water temperature and steam pressure of the boiler header, accelerates the precipitation of superheated steam condensate, prolongs the drainage time, limits the engine loading rate, and delays the time for turbine grid connection loading. Analogous to the demonstration power plant in foreign countries that canceled the engine purge, the cancellation of the engine purge and turbine grid connection loading can be advanced by 5 minutes.

[0051] Compared with the benefits of reducing system heat loss after canceling the purge, shortening the combined cycle grid-connected loading time by 20 minutes, as the grid peak-shaving response and ancillary services are increasingly valued, can bring more considerable indirect value to power plants. In addition to improving the priority mobilization sequence of power plants in the grid, it is also possible to obtain better ancillary service compensation and electricity spot trading opportunities.

[0052] The beneficial effects of the present invention are:

[0053] 1. The unit is quickly connected to the grid and put into operation to increase the corresponding power generation and heat output of the unit;

[0054] 2. The unit responds quickly to grid requirements and shows advantages in bidding for grid access;

[0055] 3. The unit starts quickly, with less heat loss on the hot water side, and the steam-water system responds quickly, which increases profits;

[0056] 4. The heat channel and boiler components have fast cooling time, which reduces thermal stress damage and extends the service life of the heat channel components;

[0057] 5. Reduce the single start-up and purge time to save factory electricity. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 It is a structural schematic diagram of a device according to an embodiment of the present invention;

[0059] Figure 2 It is a structural schematic diagram of a device according to an embodiment of the present invention;

[0060] Figure 3 A schematic diagram of an elastic purge process of a method according to an embodiment of the present invention;

[0061] Figure 4 This is a schematic diagram of the working principle of a three-out-of-two redundant voting procedure according to an embodiment of the present invention. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with specific implementation methods. It should be understood that the specific implementation methods described here are only used to explain the present invention and do not limit the scope of protection of the present invention.

[0063] Example 1

[0064] A gas turbine elastic purge device, characterized in that it comprises a gas turbine exhaust section 1, a waste heat boiler 2, and a control module (not marked);

[0065] The gas turbine exhaust section comprises a gas turbine body 11, an exhaust section 12, and a diffuser section 13 connected in sequence, and a first combustible gas detector group 3 is arranged in the exhaust section;

[0066] The waste heat boiler comprises a boiler body 21 and a chimney 22 which are connected to each other, and a second combustible gas detector group 4 is arranged in the boiler body;

[0067] The pressure diffuser section is connected to the boiler body;

[0068] The control module is connected to the combustion engine body, the first combustible gas detector group, and the second combustible gas detector group respectively.

[0069] Furthermore, the first combustible gas detector group includes at least three first combustible gas detectors 31, and the first combustible gas detectors are respectively arranged at 10 o'clock, 12 o'clock, and 2 o'clock directions along the axial exhaust direction inside the exhaust section.

[0070] Furthermore, a high-pressure area 211, a medium-pressure area 212, and a low-pressure area 213 are sequentially provided in the boiler body, and at least two heating modules 5 are respectively provided in the high-pressure area, the medium-pressure area, and the low-pressure area. The heating modules are connected in sequence, and a partition (not marked) is provided at the top between adjacent heating modules or at the top between the heating module and the chimney, and a second combustible gas detector group is provided in the partition; the second combustible gas detector group includes at least six second combustible gas detectors 41, and the second combustible gas detectors in adjacent partitions are symmetrically arranged on the left and right.

[0071] Furthermore, the control module is provided with a two-out-of-three redundant voting program, and the signals of the two-out-of-three redundant voting program are respectively taken from the first combustible gas detector group and the second combustible gas detector group.

[0072] Example 2

[0073] The present embodiment provides a gas turbine elastic purge device having the same structure as that of Embodiment 1, except that the second combustible gas detector group includes six second combustible gas detectors, which are respectively arranged in the interval at the top of the heating module in the boiler body and in the interval at the top between the heating module and the chimney. The boiler body has a total of six heating modules, and two heating modules are respectively provided in the high-pressure area, the medium-pressure area, and the low-pressure area. The first interval, the second interval, the third interval, the fourth interval, the fifth interval, and the sixth interval are arranged in sequence along the exhaust axis. The second combustible gas detectors in the first interval, the third interval, and the fifth interval are arranged on the left; the second combustible gas detectors in the second interval, the fourth interval, and the sixth interval are arranged on the right.

[0074] Example 3

[0075] The present embodiment provides a gas turbine elastic purge device having the same structure as that of Embodiment 1, except that the second combustible gas detector group includes six second combustible gas detectors, which are respectively arranged in the interval at the top of the heating module in the boiler body and in the interval at the top between the heating module and the chimney. The boiler body has a total of six heating modules, and two heating modules are respectively provided in the high-pressure area, the medium-pressure area, and the low-pressure area. The first interval, the second interval, the third interval, the fourth interval, the fifth interval, and the sixth interval are arranged in sequence along the exhaust axis. The second combustible gas detectors in the first interval, the third interval, and the fifth interval are arranged on the right; the second combustible gas detectors in the second interval, the fourth interval, and the sixth interval are arranged on the left.

[0076] Example 4

[0077] This embodiment provides a gas turbine elastic purge device having the same structure as any one of Embodiments 1-3, except that the control module includes an elastic purge control program, and the elastic purge control program is configured to include:

[0078] When the gas alarm concentration is between 1-5%LEL, the purge time will be three times the volume;

[0079] When the gas alarm concentration is between 6-25%LEL, the purge time will be five times the volume;

[0080] If the gas alarm concentration value is 0, it will directly enter the start state or manually choose whether to extend the purge time;

[0081] When the gas alarm concentration is greater than 25% LEL, check the fuel system of the gas turbine.

[0082] Preferably, the first combustible gas detector group can also be arranged at a place where the combustible gas can be easily detected according to the exhaust flow channel structure of the exhaust section, the characteristics of the combustible gas and the airflow direction.

[0083] Example 5

[0084] A gas turbine elastic purging method, characterized in that it comprises the above-mentioned gas turbine elastic purging device, comprising the following:

[0085] Add the first combustible gas detector group in the exhaust section of the gas turbine to monitor the combustible gas status in the exhaust section of the gas turbine;

[0086] Add a second combustible gas detector group to the waste heat boiler to monitor the combustible gas status of the waste heat boiler;

[0087] An elastic purge program is added to the control module to realize automatic elastic purge of the gas turbine.

[0088] Furthermore, it also includes, before starting the machine, detecting the combustible gas concentration in the exhaust section of the gas turbine and the waste heat boiler; the gas alarm concentration value is set to two alarms, and the purge procedure is divided into three levels; among them, the first-level gas alarm concentration is set at 5%LEL, the purge time is set to three times the volume time, the second-level gas alarm concentration is set at 25%LEL, the purge time is set to five times the volume time, the third-level gas alarm concentration value is 0, directly entering the startup state or manually selecting whether to extend the purge time.

[0089] Furthermore, it also includes determining that the combustible gas concentration detection program is executed for a long time, detecting the combustible gas concentration in the exhaust section of the gas turbine and the waste heat boiler after shutdown, and determining whether there is no combustible gas in the exhaust section of the gas turbine and the waste heat boiler before starting.

[0090] Furthermore, it also includes detecting the combustible gas concentration during shutdown, setting two-stage alarm for the gas alarm concentration value, and when the concentration of two or more deep detectors in the combustible gas detector group is higher than the lower explosion limit, operating according to the actual situation: when the gas alarm concentration is 1-5%LEL, entering the three-times volume purge time; when the gas alarm concentration is 6-25%LEL, entering the five-times volume purge time; when the gas alarm concentration value is 0, directly entering the startup state or manually choosing whether to extend the purge time; when the gas alarm concentration is greater than 25%LEL, the fuel system of the gas turbine is checked.

[0091] Example 6

[0092] A gas turbine elastic purging method, comprising the gas turbine elastic purging device of embodiment 1, comprising the following:

[0093] A. When shutting down, detect the combustible gas concentration in the exhaust section of the gas turbine, and set the gas alarm concentration value to two alarm levels;

[0094] B. Detect the combustible gas concentration of the waste heat boiler during shutdown, and set the gas alarm concentration value to two alarm levels;

[0095] C. When the concentration of two or more deep detectors in the combustible gas detector group is higher than a certain lower explosion limit output signal; perform the following operations: when the gas alarm concentration is 1-5%LEL, enter the three-fold volume purge time; when the gas alarm concentration is 6-25%LEL, enter the five-fold volume purge time; when the gas alarm concentration is greater than 25%LEL, check the fuel system of the gas turbine;

[0096] D. When the gas alarm concentration value is 0, it will directly enter the start state or allow the operator to choose whether to extend the purge time.

[0097] Furthermore, in step A, the combustible gas concentration in the exhaust section of the gas turbine is set to two alarm stages, the first stage is set to 5%LEL, and the second stage is set to 25%LEL; in step B, the combustible gas concentration in the waste heat boiler is set to two alarm stages, the first stage is set to 5%LEL, and the second stage is set to 25%LEL; in step C, the gas concentration data of the combustible gas detector is extracted, and the control module determines whether to send an elastic purge signal to the gas turbine through the signal obtained by the three-out-of-two redundant voting procedure.

[0098] Furthermore, purging is performed only when the combustible gas detector detects the combustible gas concentration, and no purging is performed when the combustible gas concentration is not detected.

[0099] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0100] In addition, it should be understood that although this specification is described in accordance with the implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should take the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art. It should be noted that the technical features not described in detail in the present invention can be realized by any prior art in the art.

Claims

1. A gas turbine elastic purge device, characterized in that: It includes a gas turbine exhaust section, a waste heat boiler, and a control module; the gas turbine exhaust section includes a gas turbine body, an exhaust section, and a pressure diffuser section connected in sequence, and a first combustible gas detector group is arranged in the exhaust section; the waste heat boiler includes a boiler body and a chimney connected to each other, and a second combustible gas detector group is arranged in the boiler body; the pressure diffuser section is connected to the boiler body; the control module is respectively connected to the gas turbine body, the first combustible gas detector group, and the second combustible gas detector group; The first combustible gas detector group includes at least three first combustible gas detectors, and the first combustible gas detectors are respectively arranged at 10 o'clock, 12 o'clock, and 2 o'clock directions along the axial exhaust direction inside the exhaust section; A high-pressure area, a medium-pressure area, and a low-pressure area are sequentially arranged in the boiler body, and at least two heating modules are respectively arranged in the high-pressure area, the medium-pressure area, and the low-pressure area. The heating modules are sequentially connected, and a partition is arranged on the top between adjacent heating modules and on the top between the heating module and the chimney, and a second combustible gas detector group is arranged on the partition; the second combustible gas detector group includes at least six second combustible gas detectors, and the second combustible gas detectors in adjacent partitions are symmetrically arranged on the left and right; The control module is provided with a two-out-of-three redundant voting program, and the signals of the two-out-of-three redundant voting program are respectively taken from the first combustible gas detector group and the second combustible gas detector group; The control module includes a flexible purge control program, and the settings of the flexible purge control program include: when the gas alarm concentration is 1-5% LEL, entering a purge time of three times the volume; when the gas alarm concentration is 6-25% LEL, entering a purge time of five times the volume; when the gas alarm concentration value is 0, directly entering the startup state or manually selecting whether to extend the purge time; when the gas alarm concentration is greater than 25% LEL, checking the fuel system of the gas turbine.

2. A gas turbine elastic purging method, characterized in that: The gas turbine elastic purging device described in claim 1 includes the following steps: using a first combustible gas detector group in the gas turbine exhaust section to monitor the combustible gas status of the gas turbine exhaust section; using a second combustible gas detector group in the waste heat boiler to monitor the combustible gas status of the waste heat boiler; adding an elastic purge control program to the control module to realize automatic elastic purging of the gas turbine; before starting the engine, detecting the combustible gas concentration in the gas turbine exhaust section and the waste heat boiler; setting two-stage alarms for the gas alarm concentration value, and the purging program is divided into three levels; wherein the first-level gas alarm concentration is set at 5%LEL, the purging time is set to three times the volume time, the second-level gas alarm concentration is set at 25%LEL, the purging time is set to five times the volume time, the third-level gas alarm concentration value is 0, and the startup state is directly entered or manually selected to extend the purging time.

3. The gas turbine elastic purging method according to claim 2, characterized in that: It also includes determining that the combustible gas concentration detection program is executed for a long time, detecting the combustible gas concentration in the exhaust section of the gas turbine and the waste heat boiler after shutdown, and determining whether there is no combustible gas in the exhaust section of the gas turbine and the waste heat boiler before starting.

4. The gas turbine elastic purging method according to claim 3, characterized in that: It also includes detecting the combustible gas concentration during shutdown, and setting two alarm levels for the gas alarm concentration value. When the concentration of two or more detectors in the combustible gas detector group is higher than the lower explosion limit, operation is performed according to the actual situation: when the gas alarm concentration is 1-5% LEL, the purge time is three times the volume; when the gas alarm concentration is 6-25% LEL, the purge time is five times the volume; when the gas alarm concentration value is 0, it directly enters the startup state or manually chooses whether to extend the purge time; when the gas alarm concentration is greater than 25% LEL, the fuel system of the gas turbine is checked.

5. A gas turbine elastic purging method, characterized in that: The gas turbine elastic purge device described in claim 1 includes the following steps: A. When shutting down, detecting the combustible gas concentration in the exhaust section of the gas turbine, and setting the gas alarm concentration value to two-stage alarm; B. Detecting the combustible gas concentration in the waste heat boiler when shutting down, and setting the gas alarm concentration value to two-stage alarm; C. When the concentration of two or more detectors in the combustible gas detector group is higher than a certain lower explosion limit output signal, perform the following operations: when the gas alarm concentration is 1-5% LEL, enter the purge time of three times the volume; when the gas alarm concentration is 6-25% LEL, enter the purge time of five times the volume; when the gas alarm concentration is greater than 25% LEL, check the fuel system of the gas turbine; D. When the gas alarm concentration value is 0, directly enter the startup state or let the operator choose whether to extend the purge time.

6. The gas turbine elastic purging method according to claim 5, characterized in that: In step A, the combustible gas concentration in the exhaust section of the gas turbine is set to two alarm stages, the first stage is set to 5%LEL, and the second stage is set to 25%LEL; in step B, the combustible gas concentration in the waste heat boiler is set to two alarm stages, the first stage is set to 5%LEL, and the second stage is set to 25%LEL; in step C, the gas concentration data of the combustible gas detector is extracted, and the control module determines whether to send an elastic purge signal to the gas turbine through the signal obtained by the three-out-of-two redundant voting procedure; purge is only performed when the combustible gas detector detects the combustible gas concentration, and no purge is performed when the combustible gas concentration is not detected.

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