A stable pressure-reducing blowpipe device and method for preventing dry burning of waste heat furnace reheater

Abstract

The application discloses a device and method for preventing dry burning of a reheater of a waste heat boiler, and the device comprises a high-pressure blowing unit, a medium-pressure blowing unit, a low-pressure blowing unit and a reheater unit. The high-pressure blowing unit and the medium-pressure blowing unit can ensure that the reheater unit has steam flow in the whole blowing process, and the low-pressure blowing unit can stabilize the blowing pressure. The device and method can prevent the reheater from being in a dry burning state during blowing.

Description

Technical Field

[0001] The present invention relates to the technical field of blowpipes, and in particular to a pressure-stabilizing blowpipe device and method for preventing a waste heat furnace reheater from dry burning. Background Art

[0002] The purging of the boiler steam piping system is an important process before the commissioning of a newly built unit or a unit that has undergone major technical modifications. Its purpose is to remove various debris such as sand, stones, turnings, iron oxide scale, etc. that remain in the superheater system and steam piping during the manufacturing, transportation, storage, and installation processes, to prevent superheater tube bursts and damage to the flow passage of the steam turbine during unit operation, to improve the safety and economy of the unit, and to improve the steam quality during operation.

[0003] Existing steam pipe blowing technologies for waste heat boilers either employ a staged purge of the reheater and reheater, which complicates temporary piping installation and restoration and delays gas supply, or a cascade pipe blowing process that involves dry-burning the reheater. Both existing pipe blowing technologies require the reheater to remain dry. For boiler heating surfaces, particularly those in waste heat boilers, the reheater tube bundle cannot be allowed to dry-burn when exhaust gas temperatures rise. When the emergency valve is open, steam enters the reheater system, rapidly cooling the reheater tubes. When the emergency valve is closed, steam leaves the reheater, rapidly increasing the tube wall temperature. These drastic changes in tube wall temperature generate significant alternating stresses, which can cause fatigue damage to the reheater tubes and shorten their lifespan.

[0004] Prior art, patent publication number CN112146079A, describes a supercritical unit pressure-reducing blowdown system and method. By integrating the superheater, reheater, and high-pressure bypass system, the system's overall capacity is fully utilized. The reheater volume in this scheme is approximately three times that of the superheater, significantly increasing the boiler's volumetric heat storage during blowdown. This allows for a lower initial pressure for blowdown steam, preventing the blowdoor from jamming. This also doubles the effective blowdown time, creating a "one-pipe-replacing-two" effect. Furthermore, the reheater is protected from dry-burning throughout the entire process, allowing the boiler to operate at higher loads and avoiding incomplete combustion losses associated with low-load operation. At the time, only high-pressure systems offered this type of system. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to solve the problem that the pipe blowing technology of high-pressure and medium-pressure systems both require the reheater to be kept in a dry-burning state.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A steady-pressure-reducing pipe blowing device for preventing dry burning of a waste heat furnace reheater comprises: a high-pressure purge unit, a medium-pressure purge unit, a low-pressure purge unit and a reheater unit 400. The high-pressure purge unit, the medium-pressure purge unit and the low-pressure purge unit can ensure that steam flows through the reheater unit 400 during the entire pipe blowing process.

[0008] Advantages: The high-pressure purge unit, the medium-pressure purge unit and the low-pressure purge unit can ensure that there is steam circulation in the reheater unit during the entire blowing process, so that the reheater unit will not experience dry burning and the service life of the reheater tubes is improved.

[0009] In one embodiment of the present invention, the steady-pressure blowing device for preventing dry burning of the waste heat furnace reheater also includes a target plate device 500 and a muffler 600, and the target plate device 500 and the muffler 600 are connected through a temporary main pipeline 560; and the high-pressure purge unit, the medium-pressure purge unit, the low-pressure purge unit and the reheater unit 400 are all connected to the target plate device 500 through the temporary main pipeline 560.

[0010] In one embodiment of the present invention, the high-pressure purge unit includes a high-pressure superheater 110, a high-pressure main steam valve 120, a high-pressure bypass valve 130, a high-pressure main impingement valve 140, a particle collector 150 and a high-pressure exhaust check valve 160; the high-pressure superheater 110 is pipe-connected to the reheater unit 400 in series; after the high-pressure main steam valve 120 is pipe-connected to the high-pressure superheater 110, it is pipe-connected to a high-pressure temporary pipeline 170 to the high-pressure exhaust check valve 160; wherein, the high-pressure temporary pipeline 170 is divided into two routes, and the high-pressure main impingement valve 140 and the high-pressure bypass valve 130 are respectively provided on the two routes, and the two routes are then merged and pipe-connected to the particle collector 150 and to the pipeline between the high-pressure exhaust check valve 160 and the reheater unit 400.

[0011] In one embodiment of the present invention, the high-pressure purge unit further includes a high-pressure cylinder 180 and a high-pressure bypass valve 190, and the high-pressure cylinder 180 is respectively connected to the high-pressure main steam valve 120 and the high-pressure exhaust check valve 160; the high-pressure bypass valve 190 is respectively connected to the high-pressure superheater 110 and the reheater unit 400.

[0012] In one embodiment of the present invention, the medium-pressure purge unit includes a medium-pressure superheater 210, a medium-pressure check valve 220, a medium-pressure impending manual door 230 and a medium-pressure impending door 240; the medium-pressure superheater 210 is connected to a medium-pressure temporary pipeline 250 in front of the medium-pressure check valve 220, and has two routes, one of which is connected to the medium-pressure impending manual door 230 and can be ignited and exhausted nearby, and the other is connected to the medium-pressure impending door 240 and the reheater unit 400 in sequence, and the medium-pressure superheater 210 is also connected to the medium-pressure check valve 220 and the reheater unit 400 in sequence.

[0013] In one embodiment of the present invention, the medium-pressure purge unit further includes a medium-pressure bypass valve 260, a medium-pressure main steam valve 270 and a medium-pressure cylinder 280, the medium-pressure main steam valve 270 and the medium-pressure cylinder 280 are pipe-connected, and the medium-pressure main steam valve 270 is also pipe-connected to the temporary main pipeline 560 through the medium-pressure temporary pipeline 250; the medium-pressure bypass valve 260 is pipe-connected to the temporary main pipeline 560 and the reheater unit 400.

[0014] In one embodiment of the present invention, the low-pressure purge unit includes a low-pressure superheater 310, a low-pressure air intake filter 320, a low-pressure main steam valve 330 and a low-pressure cylinder 340; the low-pressure superheater 310 is connected to the low-pressure air intake filter 320, the low-pressure main steam valve 330 and the low-pressure cylinder 340 in sequence through pipes.

[0015] In one embodiment of the present invention, the low-pressure purge unit also includes a low-pressure bypass door 350, a low-pressure bypass impending door 360, a low-pressure impending door 370 and a low-pressure impending manual door 380; the low-pressure bypass door 350 is pipe-connected to the low-pressure superheater 310, and is also pipe-connected to the low-pressure bypass impending door 360 through a low-pressure temporary pipeline 390 and then to the temporary main pipeline 560, and the low-pressure impending manual door 380 is also pipe-connected between the low-pressure bypass door 350 and the low-pressure bypass impending door 360; the low-pressure impending door 370 is pipe-connected to the high-pressure air intake filter 320 and the temporary main pipeline 560 respectively through the low-pressure temporary pipeline 390.

[0016] The present invention also provides a method for a pressure-stabilizing and pressure-reducing blowing device to prevent dry burning of a waste heat furnace reheater, comprising: a purge process of the high-pressure purge unit, a purge process of the medium-pressure purge unit, and a purge process of the low-pressure purge unit;

[0017] The purging process of the high-pressure purging unit includes: the high-pressure main steam valve 120 is blocked; when the high-pressure main steam pressure is lower than the limit pressure, the high-pressure main impending valve 140 is in a closed state; when the high-pressure main steam pressure is higher than the limit pressure, the high-pressure main impending valve 140 is fully opened, and the high-pressure main steam passes through the high-pressure superheater 110, the high-pressure main impending valve 140, the granulator 150, the reheater unit 400, the temporary main pipeline 560, the target plate device 500 and the muffler 600 in sequence, and the high-pressure superheater 110 and the reheater unit 400 are purged by pressure reduction; and in the initial stage of the blowpipe, the high-pressure bypass impending valve 190 always maintains a certain opening to perform pressure-stabilizing purging, and the high-pressure main steam enters the reheater unit 400 through the high-pressure bypass impending valve 190, ensuring that the reheater unit 400 has steam circulation during the entire blowpipe process;

[0018] The purging process of the medium-pressure purging unit includes: the medium-pressure main steam valve 270 is blocked; at the initial stage of the blowpipe, the medium-pressure impending valve 240 is closed, and the medium-pressure impending manual valve 230 is fully opened. The medium-pressure main steam passes through the medium-pressure superheater 210 and the medium-pressure impending manual valve 230 in sequence and can be ignited and exhausted nearby, and the medium-pressure superheater 210 performs pressure-stabilizing purging; after the nearby ignition exhaust steam is discharged and the medium-pressure main steam is clean, the high-pressure bypass impending valve 190 and the medium-pressure impending manual valve 230 are closed, and the medium-pressure impending valve 240 is opened. The medium-pressure main steam passes through the medium-pressure superheater 210 and the medium-pressure impending manual valve 230. The medium-pressure main steam is discharged after passing through the medium-pressure check valve 240, the reheater unit 400, the target plate device 500 and the muffler 600, and the medium-pressure main steam can also be discharged after passing through the medium-pressure check valve 220, the reheater unit 400, the target plate device 500 and the muffler 600 in sequence; the medium-pressure superheater 210 is still in a pressure-stabilizing blowpipe state, and the reheater unit 400 always has steam flowing during the entire blowpipe process; and when the high-pressure main steam valve 120 is opened, the steam at the outlet of the reheater unit 400 simultaneously reduces the pressure and purges the medium-pressure bypass where the medium-pressure bypass valve 260 is located;

[0019] The purging process of the low-pressure purging unit includes: the low-pressure main steam valve 330 is blocked; when pressure reduction purging is adopted, the low-pressure bypass 360 and the low-pressure 370 are closed, and the low-pressure main steam is pressurized. When the pressure reaches a certain level, the low-pressure bypass 360 and the low-pressure 370 are fully opened, and the main steam is pressurized and passes through the low-pressure superheater 310 and the low-pressure bypass valve 350 in turn for pressure reduction purging; when pressure stabilization purging is adopted, the low-pressure bypass 360 and the low-pressure 370 are fully opened, and the low-pressure main steam passes through the low-pressure superheater 310, the low-pressure bypass 360, the low-pressure 370, the target plate device 500 and the muffler 600 and is discharged, and the low-pressure superheater 310 is pressure-stabilized purged.

[0020] In one embodiment of the present invention, the method further includes replacing the target plate device 500. The replacement process of the target plate device 500 includes:

[0021] Close the high-pressure main Linchong door 140, the high-pressure bypass Linchong door 190, the medium-pressure Linchong manual door 230, the medium-pressure Linchong door 240, the low-pressure bypass Linchong door 360, the low-pressure Linchong door 370 and the low-pressure Linchong manual door 380, and replace the target plate device 500; when it is necessary to target a certain heated surface, fully open the corresponding Linchong door for purging.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. During the steam blowing period, steam will flow through all heating surfaces and the reheater system will no longer experience dry burning.

[0024] 2. It avoids the phenomenon of overpressure in the medium-pressure purge unit and the low-pressure purge unit and the lifting of the safety valve when the high-pressure purge unit is used in the existing purge method.

[0025] 3. The high, medium and low pressure purge units can adopt a blowing method that combines steady pressure and reduced pressure, which shortens the blowing time and has a better blowing effect.

[0026] 4. The temporary pipelines of high, medium and low pressure purge units are finally collected on the temporary main pipeline, making full use of the characteristics of short distance between formal pipelines and temporary pipelines, compact layout and convenient installation and system recovery. All heating surface systems can be used for target shooting, and the target plate device on the temporary main pipeline can be used for target shooting, which is convenient and safe to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention is a schematic diagram of a steady-pressure-reducing blowpipe device for preventing dry burning of a waste heat furnace reheater. DETAILED DESCRIPTION

[0028] To facilitate those skilled in the art to understand the technical solution of the present invention, the technical solution of the present invention is further described with reference to the accompanying drawings.

[0029] The terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0030] Please refer to Figure 1As shown, the present invention provides a steady-pressure-reducing blowing device for preventing dry burning of the waste heat furnace reheater, comprising a high-pressure purge unit, a medium-pressure purge unit, a low-pressure purge unit and a reheater unit 400. The high-pressure purge unit, the medium-pressure purge unit and the low-pressure purge unit can ensure that steam flows through the reheater unit 400 during the entire blowing process.

[0031] See also Figure 1 As shown, in one embodiment of the present invention, the steady-pressure blowing device for preventing dry burning of the waste heat furnace reheater also includes a target plate device 500 and a muffler 600, and the target plate device 500 and the muffler 600 are connected through a temporary main pipeline 560; and the high-pressure purge unit, the medium-pressure purge unit, the low-pressure purge unit and the reheater unit 400 are all connected to the target plate device 500 through a temporary main pipeline 560.

[0032] See also Figure 1 As shown, in one embodiment of the present invention, the high-pressure purge unit includes a high-pressure superheater 110, a high-pressure main steam valve 120, a high-pressure bypass valve 130, a high-pressure main impingement valve 140, a particle collector 150, and a high-pressure exhaust check valve 160. The high-pressure superheater 110 is pipe-connected to the reheater unit 400 in series. After the high-pressure main steam valve 120 is pipe-connected to the high-pressure superheater 110, it is pipe-connected to the high-pressure exhaust check valve 160 through a high-pressure temporary pipeline 170. The high-pressure temporary pipeline 170 is divided into two paths, each of which is provided with a high-pressure main impingement valve 140 and a high-pressure bypass valve 130. The two paths are then combined and pipe-connected to the particle collector 150, and then pipe-connected to the pipeline between the high-pressure exhaust check valve 160 and the reheater unit 400. The high-pressure purge unit also includes a high-pressure cylinder 180 and a high-pressure bypass valve 190. The high-pressure cylinder 180 is pipe-connected to the high-pressure main steam valve 120 and the high-pressure exhaust check valve 160, respectively. The high-pressure bypass valve 190 is pipe-connected to the high-pressure superheater 110 and the reheater unit 400, respectively. During purging, the high-pressure bypass valve 190 maintains a certain opening to ensure that steam always passes through the reheater unit 400. The high-pressure superheater 110 and the reheater unit 400 are purged using a pressure-reducing blowpipe method, while the high-pressure bypass where the high-pressure bypass valve 190 is located is purged using a blowpipe method that combines pressure stabilization and pressure reduction.

[0033] See also Figure 1As shown, in one embodiment of the present invention, the medium-pressure purge unit includes a medium-pressure superheater 210, a medium-pressure check valve 220, a medium-pressure impending manual valve 230, and a medium-pressure impending valve 240. The medium-pressure superheater 210 is connected to a medium-pressure temporary pipeline 250 before the medium-pressure check valve 220, and has two routes. One route is connected to the medium-pressure impending manual valve 230, enabling nearby ignition and exhaust steam, and the other route is connected to the medium-pressure impending valve 240 and the reheater unit 400 in sequence. The medium-pressure superheater 210 is also connected to the medium-pressure check valve 220 and the reheater unit 400 in sequence. The medium-pressure purge unit also includes a medium-pressure bypass valve 260, a medium-pressure main steam valve 270, and a medium-pressure cylinder 280. The medium-pressure main steam valve 270 and the medium-pressure cylinder 280 are pipe-connected, and the medium-pressure main steam valve 270 is also pipe-connected to the temporary main pipeline 560 via the medium-pressure temporary pipeline 250. The intermediate pressure bypass door 260 is connected to the temporary main pipeline 560 and the reheater unit 400. The intermediate pressure superheater 210 is purged by a constant pressure blowpipe method, and the intermediate pressure bypass line where the intermediate pressure bypass door 260 is located is blown by a reduced pressure blowpipe method.

[0034] See also Figure 1 As shown, in one embodiment of the present invention, the low-pressure purge unit includes a low-pressure superheater 310, a low-pressure air intake filter 320, a low-pressure main steam valve 330, and a low-pressure cylinder 340. The low-pressure superheater 310 is pipe-connected to the low-pressure air intake filter 320, the low-pressure main steam valve 330, and the low-pressure cylinder 340 in sequence. The low-pressure purge unit also includes a low-pressure bypass valve 350, a low-pressure bypass immediate-drain valve 360, a low-pressure immediate-drain valve 370, and a low-pressure immediate-drain manual valve 380. The low-pressure bypass valve 350 is pipe-connected to the low-pressure superheater 310 and is also pipe-connected to the low-pressure bypass immediate-drain valve 360 ​​via a low-pressure temporary pipe 390, and then to the temporary main pipe 560. The low-pressure immediate-drain manual valve 380 is also pipe-connected between the low-pressure bypass valve 350 and the low-pressure bypass immediate-drain valve 360. The low-pressure impending gate 370 is connected to the high-pressure air inlet filter 320 and the temporary main pipeline 560 through the low-pressure temporary pipeline 390. The low-pressure superheater 310 and the low-pressure bypass are purged by combining pressure stabilization and pressure reduction.

[0035] See also Figure 1 As shown, in one embodiment of the present invention, the steady-pressure blowpipe device for preventing dry burning of the waste heat furnace reheater also includes a condenser unit 700, and the condenser unit 700 is connected to the medium-pressure bypass door 260 and the low-pressure bypass door 350. Normally, both the medium-pressure main steam and the low-pressure main steam must enter the steam turbine. When the gas-steam combined cycle unit is initially started or in an accident state, the medium-pressure main steam can be directly recovered to the condenser unit 700 through the medium-pressure bypass without passing through the steam turbine. Similarly, the low-pressure main steam can be directly recovered to the condenser unit 700 through the low-pressure bypass without passing through the steam turbine. Among them, Figure 1 The dashed line represents a temporary pipeline, and the solid line represents a formal pipeline.

[0036] See also Figure 1 As shown, the present invention also provides a method for a steady-pressure-reducing blowpipe device to prevent dry burning of a waste heat furnace reheater, the purge process of the high-pressure purge unit, the purge process of the medium-pressure purge unit, and the purge process of the low-pressure purge unit.

[0037] The purge process of the high-pressure purge unit includes: the high-pressure main steam valve 120 is blocked. When the high-pressure main steam pressure is less than a specified pressure, the high-pressure main immediate-drain valve 140 is closed. When the high-pressure main steam pressure exceeds the specified pressure, the high-pressure main immediate-drain valve 140 is fully opened. The high-pressure main steam passes through the high-pressure superheater 110, the high-pressure main immediate-drain valve 140, the precipitator 150, the reheater unit 400, the temporary main pipeline 560, the target plate 500, and the muffler 600 in sequence, reducing the pressure of the high-pressure superheater 110 and the reheater unit 400. In the initial stage of the blowdown, the high-pressure bypass immediate-drain valve 190 is always maintained at a certain opening to maintain a constant pressure purge. The high-pressure main steam enters the reheater unit 400 through the high-pressure bypass immediate-drain valve 190, ensuring steam circulation in the reheater unit 400 throughout the blowdown process. The specified pressure is 4 MPa.

[0038] The purge process of the intermediate-pressure purge unit includes: blocking the intermediate-pressure main steam valve 270. During the initial blowdown phase, the intermediate-pressure impending valve 240 is closed, and the intermediate-pressure impending manual valve 230 is fully opened. The intermediate-pressure main steam passes through the intermediate-pressure superheater 210 and the intermediate-pressure impending manual valve 230, and can be ignited and discharged at the nearest location. The intermediate-pressure superheater 210 is purged at a constant pressure. After the nearby ignition exhaust steam has discharged the clean medium-pressure main steam, the high-pressure bypass valve 190 and the medium-pressure manual valve 230 are closed, and the medium-pressure valve 240 is opened. The medium-pressure main steam is discharged through the medium-pressure superheater 210, the medium-pressure valve 240, the reheater unit 400, the target plate 500, and the muffler 600. The medium-pressure main steam can also be discharged through the medium-pressure check valve 220, the reheater unit 400, the target plate 500, and the muffler 600 in sequence. The medium-pressure superheater 210 remains in a constant-pressure blowpipe state, and steam continues to flow through the reheater unit 400 throughout the blowpipe process. Furthermore, when the high-pressure main steam valve 120 is opened, steam from the reheater unit 400 outlet simultaneously reduces the pressure of the medium-pressure bypass where the medium-pressure bypass valve 260 is located. Among them, since the resistance of the heating surface of the medium-pressure superheater 210 is relatively small, the blowing coefficient can be greater than 1 during the two-stage pressure-stabilized blowing process.

[0039] The purging process of the low-pressure purging unit includes: the low-pressure main steam valve 330 is blocked. When pressure reduction purging is adopted, the low-pressure bypass 360 and the low-pressure 370 are closed, and the low-pressure main steam is held back. When the pressure reaches a certain level, the low-pressure bypass 360 and the low-pressure 370 are fully opened. The held-back main steam passes through the low-pressure superheater 310 and the low-pressure bypass valve 350 in sequence for pressure reduction purging. When pressure stabilization purging is adopted, the low-pressure bypass 360 and the low-pressure 370 are fully opened. The low-pressure main steam passes through the low-pressure superheater 310, the low-pressure bypass 360, the low-pressure 370, the target plate 500 and the muffler 600 and is then discharged. The low-pressure superheater 310 is purged at a stable pressure. Because higher-pressure intermediate-pressure main steam flows through the reheater unit 400, low-pressure main steam cannot flow back into the reheater unit 400 during the low-pressure purge unit's pressure-stabilizing blow. The low-pressure superheater 310 is designed with low resistance, and the blow coefficient during the pressure-stabilizing blow meets the blow guideline requirements.

[0040] See also Figure 1 As shown, in one embodiment of the present invention, the method for preventing the dry burning of the waste heat furnace reheater by the steady pressure reduction blowpipe device further includes replacing the target plate device 500, and the replacement process of the target plate device 500 includes: closing the high-pressure main rush door 140, the high-pressure bypass rush door 190, the medium-pressure rush door 230, the medium-pressure rush door 240, the low-pressure bypass rush door 360, the low-pressure rush door 370 and the low-pressure rush manual door 380, and replacing the target plate device 500. When it is necessary to target a certain heating surface, the corresponding rush door is fully opened for purging. Among them, during the period of pressure holding of the high-pressure superheater 110 and the reheater unit 400, the steam pressure of the medium-pressure superheater 210 and the low-pressure superheater 310 is quickly increased, causing the entire purge system to be at risk of overpressure. When the medium- and low-pressure main steam approaches the safety valve lifting pressure, the medium-pressure impending manual door 230 and the low-pressure impending manual door 380 in the medium- and low-pressure main steam pipelines are opened respectively to release pressure.

[0041] See also Figure 1 As shown, in one embodiment of the present invention, the present application can be extended to other types of boilers, such as dual-pressure waste heat boilers, subcritical drum boilers, supercritical once-through boilers, etc.

[0042] 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 invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description. It is intended that all variations within the meaning and range of equivalents of the claims be embraced herein, and any reference signs in the claims should not be construed as limiting the claims to which they relate.

[0043] The above-mentioned embodiments merely represent the implementation methods of the invention. The protection scope of the present invention is not limited to the above-mentioned embodiments. For those skilled in the art, several variations and improvements can be made without departing from the concept of the present invention, which all fall within the protection scope of the present invention.

Claims

1. A steady-pressure blowpipe device for preventing dry burning of the waste heat furnace reheater, characterized in that: include: A high-pressure purge unit, a medium-pressure purge unit, a low-pressure purge unit, a reheater unit (400), a target plate device (500), and a muffler (600), wherein the high-pressure purge unit, the medium-pressure purge unit, and the low-pressure purge unit can ensure that steam flows through the reheater unit (400) during the entire pipe blowing process; The target plate device (500) and the muffler (600) are connected via a temporary main pipeline (560); and the high-pressure purge unit, the medium-pressure purge unit, the low-pressure purge unit and the reheater unit (400) are all connected via a temporary main pipeline (560) to the target plate device (500). The medium-pressure purge unit includes a medium-pressure superheater (210), a medium-pressure check valve (220), a medium-pressure impending manual valve (230), a medium-pressure impending valve (240), a medium-pressure bypass valve (260), a medium-pressure main steam valve (270), and a medium-pressure cylinder (280); The medium-pressure superheater (210) is connected to a medium-pressure temporary pipeline (250) before the medium-pressure check valve (220), and has two routes. One route is connected to the medium-pressure impending manual valve (230) so as to be ignited and exhausted nearby, and the other route is connected to the medium-pressure impending valve (240) and the reheater unit (400) in sequence. The medium-pressure superheater (210) is also connected to the medium-pressure check valve (220) and the reheater unit (400) in sequence. The intermediate pressure main steam valve (270) and the intermediate pressure cylinder (280) are pipe-connected, and the intermediate pressure main steam valve (270) is also pipe-connected to the temporary main pipe (560) through the intermediate pressure temporary pipe (250); the intermediate pressure bypass valve (260) is pipe-connected to the temporary main pipe (560) and the reheater unit (400); The low-pressure purge unit includes a low-pressure superheater (310), a low-pressure air intake filter (320), a low-pressure main steam valve (330), a low-pressure cylinder (340), a low-pressure bypass valve (350), a low-pressure bypass valve (360), a low-pressure flushing valve (370), and a low-pressure flushing manual valve (380); The low-pressure superheater (310) is sequentially connected to the low-pressure air intake filter (320), the low-pressure main steam valve (330) and the low-pressure cylinder (340) through pipes; The low-pressure bypass door (350) is pipe-connected to the low-pressure superheater (310), and is also pipe-connected to the low-pressure bypass temporary door (360) through a low-pressure temporary pipe (390), and then pipe-connected to the temporary main pipe (560). In addition, a low-pressure temporary manual door (380) is pipe-connected between the low-pressure bypass door (350) and the low-pressure bypass temporary door (360). The low-pressure temporary door (370) is pipe-connected to the high-pressure air intake filter (320) and the temporary main pipe (560) through a low-pressure temporary pipe (390).

2. The stable pressure-reducing blowpipe device for preventing dry burning of the waste heat furnace reheater according to claim 1 is characterized in that: The high-pressure purge unit comprises a high-pressure superheater (110), a high-pressure main steam valve (120), a high-pressure bypass valve (130), a high-pressure main impending valve (140), a particle collector (150) and a high-pressure exhaust check valve (160); the high-pressure superheater (110) and the reheater unit (400) are connected in series by pipes; after the high-pressure main steam valve (120) and the high-pressure superheater (110) are connected by pipes, they are connected to the high-pressure exhaust check valve (160) through a high-pressure temporary pipeline (170); wherein the high-pressure temporary pipeline (170) is divided into two paths, each of which is provided with a high-pressure main impending valve (140) and a high-pressure bypass valve (130); the two paths are then combined and connected to the particle collector (150) and then to the pipeline between the high-pressure exhaust check valve (160) and the reheater unit (400).

3. The steady-pressure-reducing blowpipe device for preventing dry burning of the waste heat furnace reheater according to claim 2 is characterized in that: The high-pressure purge unit further comprises a high-pressure cylinder (180) and a high-pressure bypass valve (190); the high-pressure cylinder (180) is respectively connected to the high-pressure main steam valve (120) and the high-pressure exhaust check valve (160); and the high-pressure bypass valve (190) is respectively connected to the high-pressure superheater (110) and the reheater unit (400).

4. A method for preventing dry burning of a waste heat furnace reheater by using a steady-pressure-reducing blowpipe device according to any one of claims 1 to 3, characterized in that: include: The purging process of the high-pressure purging unit, the purging process of the medium-pressure purging unit, and the purging process of the low-pressure purging unit; The purging process of the high-pressure purging unit includes: blocking the high-pressure main steam valve (120); when the high-pressure main steam pressure is less than the limit pressure, the high-pressure main immediate valve (140) is in a closed state; when the high-pressure main steam pressure is greater than the limit pressure, the high-pressure main immediate valve (140) is fully opened, and the high-pressure main steam passes through the high-pressure superheater (110), the high-pressure main immediate valve (140), the particle collector (150), the reheater unit (400), the temporary main pipeline (560), the target plate (500) and the muffler (600) in sequence, and the high-pressure superheater (110) and the reheater unit (400) are purged by reducing the pressure; and in the initial stage of the blowpipe, the high-pressure bypass immediate valve (190) is always kept at a certain opening to perform pressure-stabilizing purging, and the high-pressure main steam enters the reheater unit (400) through the high-pressure bypass immediate valve (190), ensuring that steam flows through the reheater unit (400) during the entire blowpipe process; The purging process of the medium-pressure purging unit includes: blocking the medium-pressure main steam valve (270); at the initial stage of the blowpipe, the medium-pressure immediate valve (240) is closed, the medium-pressure immediate manual valve (230) is fully opened, and the medium-pressure main steam passes through the medium-pressure superheater (210) and the medium-pressure immediate manual valve (230) in sequence, and can be ignited and exhausted nearby, and the medium-pressure superheater (210) is purged at a constant pressure; after the nearby ignition exhaust steam is exhausted and the medium-pressure main steam is clean, the high-pressure bypass immediate valve (190) and the medium-pressure immediate manual valve (230) are closed, and the medium-pressure immediate valve (240) is opened, and the medium-pressure main steam passes through the medium-pressure superheater (210) and the medium-pressure immediate manual valve (230). 0), the medium-pressure impending valve (240), the reheater unit (400), the target plate device (500) and the muffler (600) and then discharged, and the medium-pressure main steam can also be discharged after passing through the medium-pressure check valve (220), the reheater unit (400), the target plate device (500) and the muffler (600) in sequence; the medium-pressure superheater (210) is still in a steady-pressure blowpipe state, and the reheater unit (400) always has steam flowing during the whole blowpipe process; and when the high-pressure main steam valve (120) is opened, the steam at the outlet of the reheater unit (400) simultaneously reduces the pressure and blows the medium-pressure bypass where the medium-pressure bypass valve (260) is located; The purging process of the low-pressure purging unit includes: blocking the low-pressure main steam valve (330); when pressure reduction purging is adopted, the low-pressure bypass purging valve (360) and the low-pressure purging valve (370) are closed, and the low-pressure main steam is held back. When the pressure reaches a certain level, the low-pressure bypass purging valve (360) and the low-pressure purging valve (370) are fully opened, and the held-back main steam passes through the low-pressure superheater (310) and the low-pressure bypass valve (350) in sequence for pressure reduction purging; when pressure stabilization purging is adopted, the low-pressure bypass purging valve (360) and the low-pressure purging valve (370) are fully opened, and the low-pressure main steam passes through the low-pressure superheater (310), the low-pressure bypass purging valve (360), the low-pressure purging valve (370), the target plate (500) and the muffler (600) before being discharged, and the low-pressure superheater (310) is purged with a pressure stabilization process.

5. The method for preventing dry burning of the waste heat furnace reheater according to claim 4, characterized in that: The method further comprises replacing the target plate device (500), and the target plate device (500) replacement process comprises: Close the high-pressure main linchong door (140), the high-pressure bypass linchong door (190), the medium-pressure linchong manual door (230), the medium-pressure linchong door (240), the low-pressure bypass linchong door (360), the low-pressure linchong door (370) and the low-pressure linchong manual door (380), and replace the target plate device (500); when it is necessary to target a certain heated surface, fully open the corresponding linchong door for purging.

Images