Supercritical secondary reheat boiler three-section pipeline parallel purging system

Abstract

The invention discloses a three-section pipeline parallel purging system of a supercritical secondary reheating boiler. Comprising a separator, a superheater, an ultrahigh pressure main steam valve, a superheater temporary blowing valve, a superheater target plate device, a primary reheating temporary blowing valve, a primary reheater inlet particle collector, a primary reheater, a primary reheater outlet isolating valve, a primary reheater target plate device, a secondary reheating temporary blowing valve, a secondary reheater inlet particle collector, a secondary reheater and a secondary reheater outlet isolating valve. The device comprises a secondary reheater target plate device, a temporary high bypass valve, a temporary drain valve and a silencer. By means of undisturbed switching among the superheater temporary blowing valve, the primary reheating temporary blowing valve and the secondary reheating temporary blowing valve, the defect that a temporary pipeline is switched when the boiler is shut down after pipe blowing in the first stage of the secondary reheating boiler is overcome, the starting and stopping frequency of the boiler is reduced, heat shock of all heating surfaces is reduced, the service life of the boiler is prolonged, fuel oil, fire coal and other resources are saved, and the energy-saving effect is achieved. Meanwhile, personal injury is avoided, and it is guaranteed that capital construction projects are safely and orderly conducted.

Description

Technical Field

[0001] The invention relates to the technical field of boiler pipe blowing, and in particular to a three-section pipeline parallel purge structure for a supercritical secondary reheat boiler. Background Art

[0002] With the development of economy and society, my country's large-capacity and high-parameter single reheating technology has been highly developed and widely used. However, due to the limitations of materials and other factors, the improvement of steam parameters is limited, which makes the cycle efficiency of single reheating units reach the limit. Studies have shown that increasing the number of reheating times and improving steam parameters can effectively improve unit efficiency and reduce coal consumption for power generation. At the same time, it can also effectively reduce the emission of pollutants such as nitrogen oxides and carbon dioxide. Therefore, the secondary reheating coal-fired power generation technology that integrates cleanliness, efficiency and environmental protection is the best way to improve cycle efficiency and unit performance.

[0003] Due to manufacturing, transportation, storage, installation and other reasons, there are welding slag, iron filings, iron oxide scale, rust and other impurities in the heating surface of the boiler superheater, primary reheater, secondary reheater and steam pipeline of the newly built secondary reheat unit. Before officially supplying steam to the steam turbine, the boiler superheater, primary reheater, secondary reheater and steam pipeline are purged clean by steam blowing to prevent the heating surface from being blocked by foreign objects and poor flow, which may cause boiler tube burst and turbine blade damage, and ensure the safety of the operation of the steam turbine generator set. In terms of structural design, the secondary reheat unit of the same capacity has an additional primary reheater and steam-water flow compared to the primary reheat unit, and the heating surface layout is more complicated. The turbine part has an additional ultra-high pressure cylinder and related thermal pipelines, and the system resistance is greater, which brings new challenges to the steam blowing work of the newly built secondary reheat boiler.

[0004] Conventional supercritical secondary reheat boiler pipe blowing adopts a two-stage method. In the first stage, the superheater and its pipelines are purged. The first stage of purging is carried out three times. After the superheater is purged for the third time and the target is qualified, the superheater, the primary reheater, and the secondary reheater are connected in series for the second stage of purging. The second stage of purging is carried out three times. This pipe blowing method starts and stops the furnace at least 6 times. The number of starts and stops is large. Frequent starts and stops cause each heating surface to repeatedly bear thermal shock, generate alternating stress, and seriously affect the life of the boiler. At the same time, the number of starts and stops increases the consumption of resources such as fuel oil, coal, desalted water, and steam. In addition, there are many temporary pipelines that need to be switched between the first and second stages, and they contain high-temperature steam, which is not only not conducive to the progress of the project, but also easy to cause personal injury, seriously threatening the safe and orderly advancement of infrastructure projects. Therefore, it is urgent to study a reasonable and effective supercritical secondary reheat boiler purging structure and system to ensure the safe and orderly construction and development of large-capacity and high-parameter secondary reheat units in my country. Summary of the invention

[0005] In order to solve the shortcomings of the existing conventional secondary reheat blowing technology, the purpose of the present invention is to provide a three-stage pipeline parallel blowing system for a supercritical secondary reheat boiler. Through the disturbance-free switching between the superheater pre-blowing valve, the primary reheat pre-blowing valve and the secondary reheat pre-blowing valve, the disadvantage of stopping the boiler and switching temporary pipelines after the first-stage blowing of the secondary reheat unit boiler is solved. It not only reduces the number of boiler starts and stops, reduces the thermal shock of each heating surface, avoids the generation of alternating stress, and increases the service life of the boiler, but also saves resources such as fuel oil, coal, desalted water, steam, etc., is more conducive to the progress of the project, and at the same time avoids causing personal injury, ensuring the safe and orderly advancement of the infrastructure project.

[0006] In order to achieve the above-mentioned objectives, the three-stage pipeline parallel purging system of the supercritical secondary reheat boiler described in the present invention includes: a separator, a superheater, an ultra-high pressure main steam valve, a superheater pre-purge valve, a superheater target plate device, a primary reheat pre-purge valve, a primary reheater inlet particle collector, a primary reheater, a primary reheater outlet isolation valve, a primary reheater target plate device, a secondary reheat pre-purge valve, a secondary reheater inlet particle collector, a secondary reheater, a secondary reheater outlet isolation valve, a secondary reheater target plate device, a temporary high bypass valve, a temporary drain valve and a muffler.

[0007] Superheater pipeline purging: the separator is connected to the superheater, the superheater outlet header is connected to the ultra-high pressure main steam valve through the main steam pipeline, the ultra-high pressure main steam valve is connected to the superheater temporary blowing valve through a temporary pipe, the superheater temporary blowing valve is connected to the superheater target plate through a temporary pipe, and the superheater target plate is connected to the muffler through a temporary pipe.

[0008] Purging of primary reheat pipeline: the separator is connected with the superheater, the superheater outlet header is connected with the ultra-high pressure main steam valve through the main steam pipeline, the ultra-high pressure main steam valve is connected with the primary reheat temporary blowing valve through a temporary pipe, the primary reheat temporary blowing valve is connected with the primary reheater inlet particle collector through a temporary pipe, the primary reheater inlet particle collector is connected with the primary reheater inlet header through the primary reheater cold section pipeline, the primary reheater outlet header is connected with the primary reheater outlet isolation valve through the primary reheater hot section pipeline, the primary reheater outlet isolation valve is connected with the primary reheater target plate device through a temporary pipe, and the primary reheater target plate device is connected with the muffler through a temporary pipe.

[0009] Secondary reheat pipeline purging: the separator is connected with the superheater, the superheater outlet header is connected with the ultra-high pressure main steam valve through the main steam pipeline, the ultra-high pressure main steam valve is connected with the secondary reheat temporary blowing valve through a temporary pipeline, the secondary reheat temporary blowing valve is connected with the secondary reheater inlet particle collector through a temporary pipe, the secondary reheater inlet particle collector is connected with the secondary reheater inlet header through the secondary reheater cold section pipeline, the secondary reheater outlet header is connected with the secondary reheater outlet isolation valve through the secondary reheater hot section pipeline, the secondary reheater outlet isolation valve is connected with the secondary reheater target plate through a temporary pipe, and the secondary reheater target plate is connected with the muffler through a temporary pipe.

[0010] The high-pressure bypass valve is replaced by a temporary high-pressure bypass valve.

[0011] High-pressure bypass purge: the separator is connected with the superheater, the superheater outlet header is connected with the temporary high bypass valve through the main steam pipeline and the high bypass pipeline, the temporary high bypass valve is connected with the primary reheat temporary blowing valve through the high bypass formal pipe, the primary reheat temporary blowing valve is connected with the primary reheater inlet particle collector through the temporary pipe, the primary reheater inlet particle collector is connected with the primary reheater inlet header through the primary reheater cold section pipeline, the primary reheater outlet header is connected with the primary reheater outlet isolation valve through the primary reheater hot section pipeline, the primary reheater outlet isolation valve is connected with the primary reheater target plate device through the temporary pipe, and the primary reheater target plate device is connected with the muffler through the temporary pipe.

[0012] A temporary drain valve is provided on the temporary pipeline at the muffler inlet to warm up the system pipe during the pipe blowing process.

[0013] The superheater pre-blow valve, primary reheat pre-blow valve and secondary reheat pre-blow valve are all equipped with a bypass pipe and valve with an inner diameter of not less than 50mm, which are used to warm the valve and prevent the pre-blow valve from getting stuck.

[0014] A primary reheater isolation valve is provided at the primary reheater outlet to prevent impurities such as welding slag, iron filings, iron oxide scale, rust scale, etc. in the system from flowing back into the primary reheater when the superheater pipeline and the secondary reheater pipeline are purged.

[0015] A secondary reheater isolation valve is provided at the outlet of the secondary reheater to prevent impurities such as welding slag, iron filings, iron oxide scale, rust scale, etc. in the system from flowing back into the primary reheater when the superheater pipeline and the primary reheater pipeline are purged.

[0016] The primary reheater inlet and the secondary reheater inlet are respectively provided with a primary reheater inlet particle collector and a secondary reheater inlet particle collector for collecting foreign particles in the superheater and the main steam pipeline.

[0017] The outlets of the superheater, primary reheater and secondary reheater are respectively provided with a superheater target plate device, a primary reheater target plate device and a secondary reheater target plate device, which are used to verify the purge effect and quality of the superheater, primary reheater and secondary reheater.

[0018] The outlets of the superheater, primary reheater and secondary reheater are respectively provided with target plates, so that the lengths of the superheater target plates, primary reheater target plates and secondary reheater target plates are closer to their official pipeline diameters, ensuring the authenticity and effectiveness of the purging effect.

[0019] Beneficial effects of the present invention:

[0020] 1. The present invention solves the problem that the boiler of the secondary reheat unit needs to be shut down and switched to a temporary pipeline after the first-stage pipe blowing through the non-disturbance switching between the superheater pre-blow valve, the primary reheat pre-blow valve and the secondary reheat pre-blow valve, thereby reducing the number of boiler starts and stops, reducing the thermal shock of each heating surface, avoiding the generation of alternating stress, and improving the service life of the boiler.

[0021] 2. The present invention realizes seamless connection of purging of superheater, primary reheater and secondary reheater, which saves time and improves the progress of the project compared with conventional secondary reheat unit blowing, thus ensuring the safe and orderly advancement of the infrastructure project.

[0022] 3. The present invention reduces the number of boiler starts and stops, reduces the consumption of resources such as fuel oil, coal, desalted water and steam, and improves the economy of infrastructure projects.

[0023] 4. The outlets of the superheater, primary reheater and secondary reheater of the present invention are respectively provided with target plates, so that the lengths of the superheater target plates, primary reheater target plates and secondary reheater target plates are closer to their formal pipeline diameters, ensuring the authenticity and effectiveness of the purging effect.

[0024] 5. After the superheater is blown, the present invention does not need to stop the furnace and reduce the pressure to install and switch the temporary pipeline, thus avoiding the harm of residual steam to people and having high safety performance.

[0025] 6. The outlet of the primary reheater and the outlet of the secondary reheater of the present invention are respectively provided with a primary reheater isolation valve and a secondary reheater isolation valve, which effectively prevents the impurity particles in the system from flowing back into the primary reheater and the secondary reheater when other pipelines are purged, thereby ensuring the cleanliness of the purging. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 The present invention is a schematic structural diagram of a three-stage pipeline parallel purge system for a supercritical secondary reheat boiler according to an embodiment of the present invention.

[0028]

Main component symbol description

[0029] 1. Separator; 2. Superheater outlet header; 3. Main steam pipeline; 4. Ultra-high pressure main steam valve; 5. Superheater pre-blow valve; 6. Superheater target plate; 7. Primary reheat pre-blow valve; 8. Primary reheater inlet granulator; 9. Primary reheater cold section pipeline; 10. Primary reheater inlet header; 11. Primary reheater outlet header; 12. Primary reheater hot section pipeline; 13. Primary reheater outlet isolation valve; 14. Target plate device for primary reheater; 15. Pre-blowing valve for secondary reheater; 16. Inlet particle collector for secondary reheater; 17. Cold section pipeline for secondary reheater; 18. Inlet header for secondary reheater; 19. Outlet header for secondary reheater; 20. Hot section pipeline for secondary reheater; 21. Outlet isolation valve for secondary reheater; 22. Target plate device for secondary reheater; 23. Temporary drain valve; 24. Muffler; 25. Temporary high bypass valve. DETAILED DESCRIPTION

[0030] The method of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments of the present invention.

[0031] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0032] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0033] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0034] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0035] See also Figure 1 , the present invention provides a technical solution:

[0036] A three-stage pipeline parallel purging system for a supercritical secondary reheat boiler comprises: a separator 1, a superheater, an ultra-high pressure main steam valve 4, a superheater pre-purge valve 5, a superheater target plate device 6, a primary reheat pre-purge valve 7, a primary reheater inlet particle collector 8, a primary reheater, a primary reheater outlet isolation valve 13, a primary reheater target plate device 14, a secondary reheat pre-purge valve 15, a secondary reheater inlet particle collector 16, a secondary reheater, a secondary reheater outlet isolation valve 21, a secondary reheater target plate device 22, a temporary high bypass valve 25, a temporary drain valve 23 and a muffler 24.

[0037] Superheater pipeline purging: the separator 1 is connected to the superheater, the superheater outlet header 2 is connected to the ultra-high pressure main steam valve 4 through the main steam pipeline 3, the ultra-high pressure main steam valve 4 is connected to the superheater temporary blow valve 5 through a temporary pipe, the superheater temporary blow valve 5 is connected to the superheater target plate device 6 through a temporary pipe, and the superheater target plate device 6 is connected to the muffler 24 through a temporary pipe.

[0038] Purging of primary reheat pipeline: separator 1 is connected with superheater, superheater outlet header 2 is connected with super-high pressure main steam valve 4 through main steam pipeline 3, super-high pressure main steam valve 4 is connected with primary reheat temporary blowing valve 7 through temporary pipe, primary reheat temporary blowing valve 7 is connected with primary reheater inlet particle collector 8 through temporary pipe, primary reheater inlet particle collector 8 is connected with primary reheater inlet header 10 through primary reheater cold section pipeline 9, primary reheater outlet header 11 is connected with primary reheater outlet isolation valve 13 through primary reheater hot section pipeline 12, primary reheater outlet isolation valve 13 is connected with primary reheater target plate device 14 through temporary pipe, primary reheater target plate device 14 is connected with muffler 24 through temporary pipe.

[0039] Secondary reheat pipeline purging: separator 1 is connected with superheater, superheater outlet header 2 is connected with super-high pressure main steam valve 4 through main steam pipeline 3, super-high pressure main steam valve 4 is connected with secondary reheat temporary blowing valve 15 through temporary pipeline, secondary reheat temporary blowing valve 15 is connected with secondary reheater inlet particle collector 16 through temporary pipe, secondary reheater inlet particle collector 16 is connected with secondary reheater inlet header 18 through secondary reheater cold section pipeline 17, secondary reheater outlet header 19 is connected with secondary reheater outlet isolation valve 21 through secondary reheater hot section pipeline 20, secondary reheater outlet isolation valve 21 is connected with secondary reheater target plate device 22 through temporary pipe, secondary reheater target plate device 22 is connected with muffler 24 through temporary pipe.

[0040] The high pressure bypass valve is replaced by a temporary high bypass valve 25.

[0041] High-pressure bypass purge: the separator 1 is connected with the superheater, the superheater outlet header 2 is connected with the temporary high bypass valve 25 through the main steam pipeline 3 and the high bypass pipeline, the temporary high bypass valve 25 is connected with the primary reheat temporary blowing valve 7 through the high bypass formal pipe, the primary reheat temporary blowing valve 7 is connected with the primary reheater inlet particle collector 8 through the temporary pipe, the primary reheater inlet particle collector 8 is connected with the primary reheater inlet header 10 through the primary reheater cold section pipeline 9, the primary reheater outlet header 11 is connected with the primary reheater outlet isolation valve 13 through the primary reheater hot section pipeline 12, the primary reheater outlet isolation valve 13 is connected with the primary reheater target plate device 14 through the temporary pipe, and the primary reheater target plate device 14 is connected with the muffler 24 through the temporary pipe.

[0042] A temporary drain valve 23 is provided on the temporary pipeline of the muffler 24 inlet, the superheater pre-blow valve 5, the primary reheat pre-blow valve 7 and the secondary reheat pre-blow valve 15 are all provided with bypass pipes and valves with an inner diameter of not less than 50 mm, the primary reheater outlet is provided with a primary reheater isolation valve 13, the secondary reheater outlet is provided with a secondary reheater isolation valve 21, the primary reheater inlet and the secondary reheater inlet are respectively provided with a primary reheater inlet particle collector 8 and a secondary reheater inlet particle collector 16, the superheater, primary reheater and secondary reheater outlets are respectively provided with a superheater target plate device 6, a primary reheater target plate device 14 and a secondary reheater target plate device 22.

[0043] The present invention performs steam blowing on the heating surface of a supercritical secondary reheat boiler three times, the first time blowing the superheater and 30 targets of its steam pipeline, switching the pre-blowing valve to blow the primary reheater and 30 targets of its steam pipeline, and switching the pre-blowing valve to blow the secondary reheater and 30 targets of its steam pipeline; the second time blowing the superheater and 30 targets of its steam pipeline, switching the pre-blowing valve to blow the primary reheater and 30 targets of its steam pipeline, and switching the pre-blowing valve to blow the secondary reheater and 30 targets of its steam pipeline; the third time blowing the superheater and 30 targets of its steam pipeline, after which a target shooting test is performed until qualified, switching the pre-blowing valve to blow the primary reheater and 30 targets of its steam pipeline, after which a target shooting test is performed until qualified, switching the pre-blowing valve to blow the secondary reheater and 30 targets of its steam pipeline, after which a target shooting test is performed until qualified.

[0044] First purge: purge the superheater and main steam pipeline 3. Before ignition of the boiler, open the superheater pre-purge valve 5, close the primary reheat pre-purge valve 7, the secondary reheat pre-purge valve 15 and the temporary high bypass valve 25. After ignition of the boiler, gradually close the superheater pre-purge valve 5 to control the heating rate. After the steam pressure and temperature reach a certain value, open the superheater pre-purge valve 5. The steam passes through the superheater and the main steam pipeline 3 and enters the superheater pre-purge valve 5, and is finally discharged into the atmosphere through the muffler 24. After the superheater and the main steam pipeline 3 are purged for 30 seconds, purge the primary reheater and its steam pipeline. Close the superheater pre-purge valve 5, open the primary reheat pre-purge valve 7, and then enter the primary reheater inlet collector 8, the primary reheater cold section pipeline 9, the primary reheater inlet header 10, The steam passes through the primary reheater outlet header 11, the primary reheater hot section pipeline 12 and the primary reheater outlet isolation valve 13, and then enters the exhaust main pipe, and is finally discharged into the atmosphere through the muffler 24; after the primary reheater and its steam pipeline are purged for 30 seconds, the secondary reheater and its steam pipeline are purged, the primary reheater pre-purge valve 77 is closed, and the secondary reheater pre-purge valve 7 is opened. The steam passes through the reheater and the main steam pipeline 3, enters the secondary reheater pre-purge valve 15, and then successively enters the secondary reheater inlet granulator 16, the secondary reheater cold section pipeline 17, the secondary reheater inlet header 18, the secondary reheater outlet header 19, the secondary reheater hot section pipeline 20 and the secondary reheater outlet isolation valve 21, and then enters the exhaust main pipe, and is finally discharged into the atmosphere through the muffler 24. After the secondary reheater and its steam pipeline are purged for 30 seconds, the first purge is completed.

[0045] After the first purge is completed, the boiler is shut down and cooled for more than 12 hours, and the primary reheater inlet particle collector 8 and the secondary reheater inlet particle collector 16 are cleaned.

[0046] Second purge: Similarly, the superheater and the main steam pipeline 3 are purged first. Before the boiler is ignited, the superheater pre-purge valve 5 is opened, and the primary reheat pre-purge valve 7, the secondary reheat pre-purge valve 15 and the temporary high bypass valve 25 are closed. After the boiler is ignited, the superheater pre-purge valve 5 is gradually closed to control the heating rate. After the steam pressure and temperature reach a certain value, the superheater pre-purge valve 5 is opened, and the steam passes through the superheater and the main steam pipeline 3 into the superheater pre-purge valve 5, and is finally discharged into the atmosphere through the muffler 24; after the superheater and the main steam pipeline 3 are purged for 30 seconds, the primary reheater and its steam pipeline are purged, the superheater pre-purge valve 5 is closed, and the primary reheat pre-purge valve 7 is opened. The steam passes through the superheater and the main steam pipeline 3, enters the primary reheat pre-purge valve 7, and then enters the primary reheater inlet collector 8, the primary reheater cold section pipeline 9, and the primary reheater inlet header in turn. 10. After passing through the primary reheater outlet header 11, the primary reheater hot section pipeline 12 and the primary reheater outlet isolation valve 13, the steam enters the exhaust main pipe and is finally discharged into the atmosphere through the muffler 24. After the primary reheater and its steam pipeline are purged for 30 seconds, the secondary reheater and its steam pipeline are purged, the primary reheater pre-purge valve 7 is closed, and the secondary reheater pre-purge valve 15 is opened. The steam passes through the reheater and the main steam pipeline 3 and enters the secondary reheater pre-purge valve 15. It then successively enters the secondary reheater inlet granulator 16, the secondary reheater cold section pipeline 17, the secondary reheater inlet header 18, the secondary reheater outlet header 19, the secondary reheater hot section pipeline 20 and the secondary reheater outlet isolation valve 21 and enters the exhaust main pipe and is finally discharged into the atmosphere through the muffler 24. After the secondary reheater and its steam pipeline are purged for 30 seconds, the second purge is completed.

[0047] High-pressure bypass purging: When purging the high-pressure bypass pipeline, the temporary high-pressure bypass valve 25 remains in the open state, and the steam passes through the superheater, the superheater outlet header 2, the main steam pipeline 3, the high-pressure bypass pipeline and the temporary high-pressure bypass valve 25 to enter the primary reheat temporary purge valve 7, and then successively enters the primary reheater inlet granulator 8, the primary reheater cold section pipeline 9, the primary reheater inlet header 10, the primary reheater outlet header 11, the primary reheater hot section pipeline 12 and the primary reheater outlet isolation valve 13 before entering the exhaust main pipe, and finally discharged into the atmosphere through the muffler 24. After purging a certain number of times, it is installed on the target plate device 14 for target shooting inspection to check the purging effect.

[0048] After the second purge is completed, the furnace is shut down and cooled for more than 12 hours, and the primary reheater inlet particle collector 8 and the secondary reheater inlet particle collector 16 are cleaned again.

[0049] The third purge: purge the superheater and its steam pipeline 30 targets according to the first and second purge methods. After purge, install the target plate on the superheater target plate device 6, and perform superheater target shooting until two consecutive target shootings are qualified, and the purge of the superheater and its pipeline is completed; then open the primary reheat pre-purge valve 7 to purge the primary reheater and its steam pipeline 30 targets. After purge, install the target plate on the primary reheater target plate device 14, and perform primary reheater target shooting until two consecutive target shootings are qualified, and the purge of the primary reheater and its steam pipeline is completed; finally, open the secondary reheat pre-purge valve 15 to purge the secondary reheater and its steam pipeline 30 targets. After purge, install the target plate on the secondary reheater target plate device 22, and perform secondary reheater target shooting until two consecutive target shootings are qualified, and the purge of the secondary reheater and its steam pipeline is completed.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention.

Claims

1. A three-stage pipeline parallel purge system for a supercritical double reheat boiler, characterized in that: include: Separator (1), superheater, super-high pressure main steam valve (4), superheater pre-blow valve (5), superheater target plate device (6), primary reheat pre-blow valve (7), primary reheater inlet particle collector (8), primary reheater, primary reheater outlet isolation valve (13), primary reheater target plate device (14), secondary reheat pre-blow valve (15), secondary reheater inlet particle collector (16), secondary reheater, secondary reheater outlet isolation valve (21), secondary reheater target plate device (22), temporary high bypass valve (25), temporary steam trap (23) and silencer (24); Superheater pipeline purging: the separator (1) is connected to the superheater, the superheater outlet header (2) is connected to the super-high pressure main steam valve (4) through the main steam pipeline (3), the super-high pressure main steam valve (4) is connected to the superheater temporary blow valve (5) through a temporary pipe, the superheater temporary blow valve (5) is connected to the superheater target plate device (6) through a temporary pipe, and the superheater target plate device (6) is connected to the muffler (24) through a temporary pipe; Primary reheat pipeline purging: the separator (1) is connected to the superheater, the superheater outlet header (2) is connected to the super-high pressure main steam valve (4) through the main steam pipeline (3), the super-high pressure main steam valve (4) is connected to the primary reheat pre-purge valve (7) through a temporary pipe, the primary reheat pre-purge valve (7) is connected to the primary reheater inlet granulator (8) through a temporary pipe, the primary reheater inlet granulator (8) is connected to the primary reheater inlet header (10) through the primary reheater cold section pipeline (9), the primary reheater outlet header (11) is connected to the primary reheater outlet isolation valve (13) through the primary reheater hot section pipeline (12), the primary reheater outlet isolation valve (13) is connected to the primary reheater target plate device (14) through a temporary pipe, and the primary reheater target plate device (14) is connected to the muffler (24) through a temporary pipe; Secondary reheat pipeline purging: the separator (1) is connected to the superheater, the superheater outlet header (2) is connected to the super-high pressure main steam valve (4) through the main steam pipeline (3), the super-high pressure main steam valve (4) is connected to the secondary reheat pre-purge valve (15) through a temporary pipeline, the secondary reheat pre-purge valve (15) is connected to the secondary reheater inlet granulator (16) through a temporary pipe, the secondary reheater inlet granulator (16) is connected to the secondary reheater inlet header (18) through the secondary reheater cold section pipeline (17), the secondary reheater outlet header (19) is connected to the secondary reheater outlet isolation valve (21) through the secondary reheater hot section pipeline (20), the secondary reheater outlet isolation valve (21) is connected to the secondary reheater target plate (22) through a temporary pipe, and the secondary reheater target plate (22) is connected to the muffler (24) through a temporary pipe; The high pressure bypass valve is replaced by a temporary high pressure bypass valve (25); High-pressure bypass purge: the separator (1) is connected to the superheater, the superheater outlet header (2) is connected to the temporary high-pressure bypass valve (25) through the main steam pipeline (3) and the high-pressure bypass pipeline, the temporary high-pressure bypass valve is connected to the primary reheat temporary blow valve (7) through the high-pressure bypass formal pipe, the primary reheat temporary blow valve (7) is connected to the primary reheater inlet granulator (8) through the temporary pipe, the primary reheater inlet granulator (8) is connected to the primary reheater inlet header (10) through the primary reheater cold section pipeline (9), the primary reheater outlet header (11) is connected to the primary reheater outlet isolation valve (13) through the primary reheater hot section pipeline (12), the primary reheater outlet isolation valve (13) is connected to the primary reheater target plate device (14) through the temporary pipe, and the primary reheater target plate device (14) is connected to the muffler (24) through the temporary pipe.

2. The three-stage pipeline parallel purge system for a supercritical double reheat boiler according to claim 1 is characterized in that: A temporary drain valve (23) is provided on the temporary pipeline at the inlet of the muffler (24).

3. The three-stage pipeline parallel purge system for a supercritical double reheat boiler according to claim 1 is characterized in that: The superheater pre-blow valve, primary reheat pre-blow valve and secondary reheat pre-blow valve are all equipped with bypass pipes and valves with an inner diameter of not less than 50mm.

4. The three-stage pipeline parallel purge system for a supercritical double reheat boiler according to claim 1 is characterized in that: A primary reheater isolation valve (13) is provided at the primary reheater outlet.

5. The three-stage pipeline parallel purge system for a supercritical double reheat boiler according to claim 3 or 4, characterized in that: The primary reheater inlet and the secondary reheater inlet are respectively provided with a primary reheater inlet particle collector (8) and a secondary reheater inlet particle collector (16).

6. The three-stage pipeline parallel purge system for a supercritical double reheat boiler according to claim 1 is characterized in that: A secondary reheater isolation valve (21) is provided at the secondary reheater outlet.

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