A multi-layer protection structure for high-temperature and high-pressure pipelines in a thermal power plant

Abstract

The present application relates to the technical field of high-temperature and high-pressure thermal pipeline protection in thermal power plants, and proposes a multi-layer protection structure for high-temperature and high-pressure pipelines in thermal power plants, which comprises a base module, a mounting module, a buffer anti-collision module and a support adjustment module. The base module comprises an inner shell, the outer side of which is covered with a high-temperature-resistant insulation layer, the outer side of which is covered with a steam and water blocking layer, the outer side of which is covered with a middle insulation filling layer, and the outer side of which is covered with an auxiliary steam blocking layer. The mounting module is sleeved on the outer side of the auxiliary steam blocking layer and is used to connect with adjacent pipelines. The buffer anti-collision module is arranged between the auxiliary steam blocking layer and the mounting module, and the support adjustment module is arranged on the outer side of the mounting module. Through the multi-dimensional cooperation of "gradient composite insulation + trapezoidal labyrinth seal + triangular buffer support + sliding positioning adjustment + optical fiber intelligent monitoring", the long-period safe operation requirements of supercritical / ultra-supercritical thermal power generating units for high-temperature and high-pressure pipelines are met.

Description

Technical Field

[0001] This invention relates to the field of protection technology for high-temperature and high-pressure thermal pipelines in thermal power plants, specifically to a multi-layer protection structure for high-temperature and high-pressure pipelines in thermal power plants. Background Technology

[0002] The main steam and reheat steam pipelines of thermal power plants operate under conditions of high temperature above 540℃ and high pressure of 16MPa for extended periods. Therefore, the outer wall of these pipelines must be equipped with a multi-layered composite protective structure to achieve thermal insulation, steam and water barrier, protection against external impacts, and corrosion protection. Existing traditional protective structures have four major defects:

[0003] First, defects in splicing, sealing, and assembly: The two-section protective outer shell typically uses flanges and multiple sets of bolts for tightening and sealing. Construction requires torque wrenches, gaskets, and bolts of various specifications, with each bolt individually and evenly tightened to ensure coaxiality. This process is complex and time-consuming. Under the unit's hot and cold cycles, the bolts experience thermal creep and loosen their pre-tightening force, leading to gaps on the flange sealing surface. Rainwater and acidic moisture from the furnace area can then seep into the insulation layer, significantly increasing the thermal conductivity of the insulation and inducing corrosion beneath the insulation layer, thus shortening the pipeline's service life. Planar lap joint seals have short moisture penetration paths and poor seepage prevention performance.

[0004] Second, the installation of external supports damages the waterproof structure: pipe clamps and supports need to be fixed by opening holes in the protective shell, which creates permanent water seepage channels and damages the overall vapor barrier and waterproof system; when the spacing of the supports is not uniform, secondary openings need to be made on site, which results in low construction efficiency and damage to the integrity of the shell.

[0005] Third, the outer shell has weak impact and deformation resistance: there is no rigid buffer support frame between the insulation layer and the outer shell, and collisions with vehicles and equipment in the factory area can easily cause the outer shell to dent and squeeze the inner vapor barrier membrane; the thermal expansion and contraction during the start-up and shutdown of the unit generates continuous compressive stress, and after long-term operation, the insulation layer delaminates and the vapor barrier membrane is punctured by the metal support, resulting in insulation failure.

[0006] Fourth, there is no online status monitoring method: the existing protective structure relies solely on manual periodic inspections, and issues such as water seepage in the interlayer, overheating of the insulation, and deformation of the outer shell cannot be detected in advance; after a failure occurs, the machine can only be shut down and the outer shell removed for inspection, resulting in high operation and maintenance costs and the potential safety hazard of pipe bursts.

[0007] In view of this, the present invention proposes a multi-layer protection structure for high-temperature and high-pressure pipelines in thermal power plants. Summary of the Invention

[0008] This invention proposes a multi-layer protection structure for high-temperature and high-pressure pipelines in thermal power plants, which solves the problem that existing technologies cannot fully meet the safety protection needs of high-temperature and high-pressure pipelines throughout their entire life cycle in thermal power plants.

[0009] The technical solution of the present invention is as follows: a multi-layer protection structure for high-temperature and high-pressure pipelines in thermal power plants, comprising a basic module, an installation module, a buffer anti-collision module, and a support and adjustment module;

[0010] The basic module includes an inner shell, the outer side of which is covered with a high-temperature resistant insulation layer, the outer side of which is covered with a vapor barrier and water barrier layer, the outer side of which is covered with a middle insulation filling layer, and the outer side of which is covered with an auxiliary vapor barrier layer.

[0011] The installation module is fitted onto the outside of the auxiliary vapor barrier and is used to connect to adjacent pipelines;

[0012] The buffer anti-collision module is installed between the auxiliary vapor barrier layer and the installation module to buffer and protect the inner shell;

[0013] The support adjustment module is located on the outside of the installation module and is used to support the installation module.

[0014] Preferably, the high-temperature resistant insulation layer is a high-density, high-purity alumina ceramic fiber blanket, the middle insulation filling layer is a medium-density aluminum silicate fiber layer, and the vapor barrier and water barrier layer and the auxiliary vapor barrier layer are both nano-aluminum foil composite polytetrafluoroethylene vapor barrier membranes.

[0015] Preferably, the installation module includes an outer shell concentrically arranged with the inner shell, a sleeve is fixedly connected to one end of the outer shell, a plurality of limiting protrusions are fixedly connected to the inner side of the sleeve along its axial direction, and a fixing ring is fixedly connected to the other end of the outer shell, and the outer wall of the fixing ring is provided with a plurality of annular grooves corresponding one-to-one with the limiting protrusions.

[0016] Preferably, the cross-section of the limiting protrusion is trapezoidal, the annular groove is a trapezoidal groove, and the limiting protrusions of the two outer shells of the adjacent pipes are clearance-fitted with the annular groove.

[0017] Preferably, the contact surface between the limiting protrusion and the annular groove is coated with high-temperature acid and alkali resistant sealant to form a multi-level bent labyrinth seepage prevention channel.

[0018] Preferably, the buffer anti-collision module includes a first support ring sleeved on the outside of the auxiliary vapor barrier, a second support ring sleeved on the outside of the first support ring and concentrically arranged and abutting against the inner wall of the outer shell, and a plurality of reinforcing ribs arranged in a circumferential array are fixedly connected between the second support ring and the first support ring, and buffer felt is filled between two adjacent reinforcing ribs.

[0019] Preferably, the reinforcing rib is a triangular radial support rib, and the buffer felt is an alkali-free high-resilience ceramic fiber felt that fills the gaps in the reinforcing rib, so as to absorb the stress of cold and heat deformation during unit start-up and shutdown and the vibration of pipeline operation.

[0020] Preferably, the support adjustment module includes a movable ring sleeved on the outer side of the outer shell, a plurality of sliders arranged in a ring are fixedly connected to the inner wall of the movable ring, a plurality of movable grooves that slide with the sliders are opened on the outer wall of the outer shell, a plurality of positioning holes are opened on the inner wall of the two movable grooves at the front end and the rear end of the outer shell, and a plurality of positioning holes are equidistantly distributed along their length direction. The front end and the rear end of the movable ring are provided with positioning elements for fixing with the positioning holes.

[0021] Preferably, the positioning element includes a sleeve fixedly connected to the outside of the movable ring, a positioning rod slidably connected to the inner side of the sleeve and passing through the sleeve, a pull block fixedly connected to one end of the positioning rod, the other end of the positioning rod slidably engaging with a corresponding positioning hole, a guide block fixedly connected to the middle of the positioning rod, the guide block slidably connecting to the inner wall of the sleeve, and a return spring sleeved on the inner side of the sleeve, the two ends of the return spring respectively abutting against the inner wall of the sleeve and the guide block.

[0022] Preferably, the housing is provided with an optical fiber monitoring module, which includes an optical fiber lead connector fixedly connected to the outer wall of the housing. The input end of the optical fiber lead connector is connected to multiple sets of fiber Bragg grating sensing cables for detecting temperature, humidity and strain. The multiple sets of fiber Bragg grating sensing cables are respectively embedded in the high-temperature insulation layer, the vapor barrier and water barrier layer, the middle insulation filling layer and the auxiliary vapor barrier layer. The output end of the optical fiber lead connector is connected to a wire, and the output end of the wire is electrically connected to a signal demodulation terminal.

[0023] The beneficial effects of this invention are as follows:

[0024] 1. The basic module adopts a gradient composite structure: the inner layer of alumina ceramic fiber blanket can withstand temperatures above 600℃ and will not pulverize during long-term service; the middle layer of aluminosilicate fiber fills the gaps and blocks heat conduction; double-layer nano-aluminum foil composite polytetrafluoroethylene vapor barrier membranes are respectively set on the inner and outer sides of the insulation layer, the aluminum foil reflects residual heat radiation, and the polytetrafluoroethylene is resistant to acid and alkali corrosion; this design reduces the outer surface temperature of high-temperature and high-pressure pipelines to below 50℃ as required by DL / T 5072, reducing heat loss compared to the traditional single-layer insulation cotton solution, and ensuring the stability of the main steam temperature of the steam turbine; at the same time, the outer surface temperature meets the standard to avoid accidental burns to inspection personnel, and the acid and alkali resistance of the polytetrafluoroethylene vapor barrier membrane resists the corrosive media in the desulfurization and denitrification areas, extending the service life of the insulation structure compared to the traditional rock wool solution.

[0025] 2. The installation module adopts a tenon-and-groove joint structure of "sleeve and fixing ring at the end of the outer shell". When adjacent pipes are connected, the trapezoidal bevel automatically corrects axial / radial deviations, achieving rapid concentric alignment. The gap between the limiting protrusion ring and the annular groove is reserved to allow for thermal expansion, avoiding stress concentration in rigid connections. The contact surface is sprayed with high-temperature acid and alkali resistant sealant to form a multi-level bent labyrinth seepage prevention channel, which extends the water vapor permeation path. This design greatly shortens the connection time of a single set of pipes and improves the tolerance of connection error.

[0026] 3. The triangular reinforcing ribs of the buffer and anti-collision module rely on geometric stability to evenly transfer external impact loads and avoid local stress overload. The buffer felt fills the gaps between the reinforcing ribs and converts mechanical energy into heat energy through the fiber pore structure, absorbing the stress of cold and heat deformation during unit start-up and shutdown and pipeline operation vibration. This design improves the impact resistance of the outer shell and can withstand common impacts such as dropped maintenance tools and accidental contact by personnel. The high resilience of the buffer felt absorbs the vibration energy of pipeline operation, avoiding long-term vibration that could cause the insulation layer to delaminate and the vapor barrier membrane to break. Moreover, it does not burn or pulverize at a high temperature of 600℃, making it suitable for high-temperature pipeline service environments.

[0027] 4. The movable ring of the support adjustment module slides axially along the movable groove via a slider to adapt to different site elevation differences; the positioning component uses a linkage design of "pull block - positioning rod - guide block - return spring", which can be unlocked by pulling the pull block with one hand. After releasing, the return spring pushes the positioning rod into the positioning hole to complete the locking. The return spring is continuously pre-tightened to ensure vibration resistance and anti-loosening; this design does not require on-site drilling to damage the waterproof structure of the outer shell, and the range of support position adjustment is expanded to adapt to different support and hanger spacing requirements. Attached Figure Description

[0028] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0029] Figure 1 This is a schematic diagram of a multi-layer protection structure for high-temperature and high-pressure pipelines in thermal power plants according to the present invention.

[0030] Figure 2 This is an exploded view of a multi-layered protective structure for high-temperature and high-pressure pipelines in thermal power plants according to the present invention.

[0031] Figure 3 This is a schematic diagram of the basic module of the present invention;

[0032] Figure 4 This is a schematic diagram of the installation module of the present invention;

[0033] Figure 5 This is a schematic diagram of the structure of the buffer anti-collision module of the present invention;

[0034] Figure 6 This is a schematic diagram of the support adjustment module of the present invention;

[0035] Figure 7 This is a schematic diagram of the structure of the movable ring of the present invention;

[0036] Figure 8 for Figure 7 Enlarged structural diagram at point A;

[0037] Figure 9This is a schematic diagram of the fiber optic monitoring module of the present invention.

[0038] In the diagram: 1. Basic module; 11. Inner shell; 12. High-temperature resistant insulation layer; 13. Vapor barrier and water barrier layer; 14. Middle insulation filling layer; 15. Auxiliary vapor barrier layer; 2. Installation module; 21. Outer shell; 22. Sleeve; 23. Limiting protrusion ring; 24. Fixing ring; 25. Annular groove; 3. Buffer and anti-collision module; 31. First support ring; 32. Second support ring; 33. Reinforcing rib; 34. Buffer felt; 4. Support adjustment module; 41. Movable ring; 42. Slider; 43. Movable groove; 44. Positioning component; 441. Sleeve; 442. Positioning rod; 443. Pull block; 444. Guide block; 445. Return spring; 45. Positioning hole; 5. Fiber optic monitoring module; 51. Fiber optic lead connector; 52. Wire; 53. Signal demodulation terminal. Detailed Implementation

[0039] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0040] like Figures 1 to 9 As shown, this embodiment proposes a multi-layer protection structure for high-temperature and high-pressure pipelines in thermal power plants, including a basic module 1, an installation module 2, a buffer anti-collision module 3, and a support and adjustment module 4.

[0041] The basic module 1 includes an inner shell 11, the outer side of which is covered with a high-temperature resistant insulation layer 12, the outer side of which is covered with a vapor barrier and water barrier layer 13, the outer side of which is covered with a middle insulation filling layer 14, and the outer side of which is covered with an auxiliary vapor barrier layer 15.

[0042] The installation module 2 is fitted onto the outside of the auxiliary vapor barrier 15 for connection with adjacent pipes;

[0043] The buffer anti-collision module 3 is set between the auxiliary vapor barrier layer 15 and the installation module 2 to provide buffer protection for the inner shell 11;

[0044] The support adjustment module 4 is located on the outside of the mounting module 2 and is used to support the mounting module 2.

[0045] In this embodiment, the inner shell 11 serves as the basic load-bearing layer, adhering to the outer wall of the high-temperature and high-pressure pipeline. Its outer side is sequentially covered with a high-temperature resistant insulation layer 12, a vapor barrier and water barrier layer 13, a middle insulation filling layer 14, and an auxiliary vapor barrier layer 15, forming a multi-layer composite protection system from the inside out. The installation module 2 is fitted onto the outside of the auxiliary vapor barrier layer 15, and the adjacent pipeline protection structures are quickly connected and sealed through tenon and mortise joints. The buffer and anti-collision module 3 is filled between the auxiliary vapor barrier layer 15 and the installation module 2, absorbing external impact loads and pipeline operation vibrations, while buffering the thermal expansion and contraction stress during the start-up and shutdown of the unit. The support adjustment module 4 is installed on the outside of the installation module 2, and the installation height is adjusted through linear sliding and multi-point positioning to adapt to the support requirements of different sites.

[0046] The design employs a four-layer composite insulation structure, which significantly reduces the outer surface temperature of the pipe compared to bare pipe, thereby reducing heat loss and meeting the requirements of the "Design Code for Thermal Power Plant Insulation and Painting". The gradient insulation design avoids structural cracking caused by excessive internal and external temperature differences in single-layer insulation, thus extending its service life. The modular design shortens the installation time of a single-section pipe protection structure and greatly improves efficiency compared to traditional on-site wrapping.

[0047] In a further preferred embodiment of the present invention, the high-temperature resistant insulation layer 12 is a high-density, high-purity alumina ceramic fiber blanket, the middle insulation filling layer 14 is a medium-density aluminum silicate fiber layer, and the vapor barrier and water barrier layer 13 and the auxiliary vapor barrier layer 15 are both nano-aluminum foil composite polytetrafluoroethylene vapor barrier membranes.

[0048] In this embodiment, the high-temperature resistant insulation layer 12 made of high-density, high-purity alumina ceramic fiber maintains fiber structure stability under long-term working conditions above 600°C, and its highly dense fiber interwoven network can effectively block heat radiation and heat convection in high-temperature pipelines; the middle insulation filling layer 14 made of medium-density aluminosilicate fiber fills the gap between the high-temperature resistant insulation layer 12 and the vapor barrier and water barrier layer 13, and further reduces heat conduction efficiency by relying on its own porous structure; the vapor barrier and water barrier layer 13 made of nano-aluminum foil composite polytetrafluoroethylene and the auxiliary vapor barrier layer 15 are respectively disposed on the inner and outer sides of the insulation layer; the nano-aluminum foil layer can reflect residual heat radiation, and the polytetrafluoroethylene layer can withstand acid and alkali corrosion and high-temperature oxidation in the power plant environment;

[0049] The gradient composite insulation structure of this design reduces the outer surface temperature of the pipeline compared to traditional single-layer insulation, thus reducing heat loss and meeting the energy conservation and consumption reduction requirements of the thermal power industry. The high-density alumina ceramic fiber has a long-term service temperature of up to 1000℃, making it suitable for the service environment of high-temperature pipelines in supercritical units, and its service life is more than three times longer than that of traditional rock wool insulation. The acid and alkali resistance of the polytetrafluoroethylene vapor barrier can resist the corrosive media in the desulfurization and denitrification areas of power plants, preventing the insulation layer from becoming damp and failing.

[0050] In a further preferred embodiment of the present invention, the installation module 2 includes an outer shell 21 concentrically disposed with the inner shell 11. A sleeve 22 is fixedly connected to one end of the outer shell 21. A plurality of limiting protrusions 23 are fixedly connected to the inner side of the sleeve 22 at equal intervals along its axial direction. A fixing ring 24 is fixedly connected to the other end of the outer shell 21. A plurality of annular grooves 25 corresponding one-to-one with the limiting protrusions 23 are opened on the outer wall of the fixing ring 24. The cross section of the limiting protrusions 23 is trapezoidal, and the annular grooves 25 are trapezoidal grooves. The limiting protrusions 23 of the two outer shells 21 of adjacent pipes are clearance-fitted with the annular grooves 25.

[0051] In this embodiment, the trapezoidal limiting protrusion 23 and the corresponding trapezoidal annular groove 25 form a clearance fit. The inclined guiding characteristics of the trapezoid can automatically correct the axial and radial deviations when adjacent pipes are connected, so that the two sets of shells 21 can quickly achieve concentric alignment. The deformation allowance reserved by the clearance fit can accommodate the axial thermal expansion displacement during the start-up and shutdown process of the high-temperature pipe, and avoid structural stress concentration caused by rigid connection.

[0052] Among them, the self-centering characteristic of the trapezoidal tenon and groove structure improves the tolerance of installation error in pipe connection and greatly shortens the connection time of a single set; the clearance fit design can absorb the axial thermal expansion of the pipe, avoid the limit structure from cracking due to thermal stress deformation, improve the vibration resistance and loosening ability of the connection part, and adapt to the long-term high-frequency start and stop conditions of the unit.

[0053] In a further preferred embodiment of the present invention, the contact surfaces of the limiting protrusion 23 and the annular groove 25 are sprayed with high-temperature acid and alkali resistant sealant to form a multi-level bent labyrinth seepage prevention channel.

[0054] In this embodiment, after the high-temperature acid and alkali resistant sealant is sprayed onto the contact surface between the limiting protrusion 23 and the annular groove 25, a continuous sealing layer is formed in the gap of the trapezoidal mating surface. The bending structure of the tenon groove creates a multi-level meandering seepage path, which greatly extends the penetration distance of external water vapor and corrosive media. The sealant maintains vulcanization elasticity in a high-temperature environment and can expand and contract synchronously with the slight deformation of the mating surface, avoiding cracking of the sealing layer caused by temperature fluctuations.

[0055] The multi-level bend labyrinth structure extends the water vapor penetration path, and combined with the elastic compensation properties of the sealant, it improves the seepage prevention level of the joint. The sealant has a temperature resistance range of -40℃ to 300℃, which can be adapted to the extreme climate of extremely cold winters and high summers in the north, reducing the frequency of on-site sealing maintenance.

[0056] In a further preferred embodiment of the present invention, the buffer anti-collision module 3 includes a first support ring 31 sleeved on the outside of the auxiliary vapor barrier layer 15, and a second support ring 32 concentrically arranged and abutting against the inner wall of the outer shell 21 on the outside of the first support ring 31. A plurality of reinforcing ribs 33 arranged in a circumferential array are fixedly connected between the second support ring 32 and the first support ring 31, and a buffer felt 34 is filled between two adjacent reinforcing ribs 33. The reinforcing ribs 33 are triangular radial support ribs, and the buffer felt 34 is an alkali-free high-resilience ceramic fiber felt that fills the gaps in the reinforcing ribs 33, which is used to absorb the extrusion stress of cold and heat deformation during unit start-up and shutdown and the vibration of pipeline operation.

[0057] In this embodiment, the reinforcing ribs 33 with triangular cross sections are arranged in a circular array. Relying on the geometric stability of the triangle, the external impact load and pipeline vibration received by the outer shell 21 are uniformly transmitted to the first support ring 31, avoiding local stress overload. The buffer felt 34 made of alkali-free high-resilience ceramic fiber material is filled in the gaps of the reinforcing ribs 33. Its high porosity fiber structure can convert mechanical energy into heat energy dissipation, and at the same time absorb the compressive stress generated by the cold and hot deformation of the pipeline during the start-up and shutdown of the unit, so as to avoid the insulation layer from cracking due to compression.

[0058] The radial support structure with triangular reinforcing ribs in this design enhances the impact resistance of the protective structure's outer shell, enabling it to withstand common impacts such as dropped maintenance tools and accidental contact by personnel. The high resilience of the buffer felt absorbs the vibration energy of pipeline operation, preventing the thermal insulation performance from deteriorating due to long-term vibration. The temperature resistance of the ceramic fiber material ensures that the buffer structure will not burn or pulverize at 600℃, making it suitable for the service environment of high-temperature pipelines.

[0059] In a further preferred embodiment of the present invention, the support adjustment module 4 includes a movable ring 41 sleeved on the outside of the outer shell 21. A plurality of annularly distributed sliders 42 are fixedly connected to the inner wall of the movable ring 41. A plurality of movable grooves 43 are provided on the outer wall of the outer shell 21 to slide against the sliders 42. A plurality of positioning holes 45 are provided on the inner walls of the two movable grooves 43 at the front and rear ends of the outer shell 21, equidistantly distributed along their length. Positioning members 44 for fixing to the positioning holes 45 are provided at both the front and rear ends of the movable ring 41. The positioning members 44 include fixed connections. On the outer side of the movable ring 41, there is a sleeve 441. A positioning rod 442 is slidably connected to the inner side of the sleeve 441. One end of the positioning rod 442 is fixedly connected to a pull block 443. The other end of the positioning rod 442 is slidably engaged with the corresponding positioning hole 45. A guide block 444 is fixedly connected to the middle of the positioning rod 442. The guide block 444 is slidably connected to the inner wall of the sleeve 441. A return spring 445 is sleeved on the inner side of the sleeve 441. The two ends of the return spring 445 abut against the inner wall of the sleeve 441 and the guide block 444, respectively.

[0060] In this embodiment, the movable ring 41 slides axially along the movable groove 43 on the outer wall of the outer shell 21 via the slider 42 on the inner wall. The clearance fit between the slider and the movable groove can ensure the straightness of the movable ring 41 during the sliding process and avoid skew and jamming. The positioning holes 45 evenly distributed along the length of the movable groove 43 on the outer shell 21 provide multi-level height adjustment points for the movable ring 41 to adapt to the elevation differences of different installation sites.

[0061] When the position of the movable ring 41 needs to be adjusted, pulling the pull block 443 outward causes the positioning rod 442 to slide along the inner wall of the sleeve 441 with the guide block 444, compressing the return spring 445 to accumulate elastic potential energy. When the movable ring 41 slides to the target height, the pull block 443 is released, and the return spring 445 releases its potential energy to push the guide block 444 and the positioning rod 442 back to their original positions, allowing the positioning rod 442 to be inserted into the corresponding positioning hole 45 to complete the locking. The sliding cooperation between the guide block 444 and the sleeve 441 ensures the stability of the sliding trajectory of the positioning rod 442 and avoids skew and jamming. The continuous preload provided by the return spring 445 increases the locking pull resistance of the positioning component, which can resist the risk of loosening caused by unit operation vibration, and the locking reliability is improved compared with traditional bolt fixing. The unlocking operation can be completed by pulling the pull block 443 with one hand, without the need for special tools, which greatly improves the convenience of disassembly during later maintenance and significantly reduces maintenance time.

[0062] In a further preferred embodiment of the present invention, an optical fiber monitoring module 5 is provided on the outer shell 21. The optical fiber monitoring module 5 includes an optical fiber lead connector 51 fixedly connected to the outer wall of the outer shell 21. The input end of the optical fiber lead connector 51 is connected to multiple sets of fiber optic grating sensing cables for detecting temperature, humidity and strain. The multiple sets of fiber optic grating sensing cables are respectively embedded in the high-temperature insulation layer 12, the vapor barrier and water barrier layer 13, the middle insulation filling layer 14, and the auxiliary vapor barrier layer 15. The output end of the optical fiber lead connector 51 is connected to a wire 52. The output end of the wire 52 is electrically connected to a signal demodulation terminal 53.

[0063] In this embodiment, multiple sets of fiber Bragg grating sensing cables are respectively embedded inside the high-temperature insulation layer 12, the vapor barrier and water barrier layer 13, the middle insulation filling layer 14, and the auxiliary vapor barrier layer 15. Relying on the wavelength drift characteristics of the fiber Bragg grating, the temperature, humidity and strain changes of each layer are sensed respectively. The sensed signals are transmitted to the signal demodulation terminal 53 through the fiber optic connector 51 and the wire 52. After demodulation and analysis, the real-time status data of each layer is obtained, realizing early warning of abnormal conditions.

[0064] The distributed buried sensing optical cables in this design enable real-time monitoring of the insulation structure throughout its entire life cycle, improving the accuracy of temperature and strain monitoring. This allows for early warning of potential faults such as moisture absorption, localized overheating, and structural deformation in the insulation layer. The inherent safety characteristics of fiber optic sensing enable stable operation in high-temperature, high-electromagnetic-interference thermal power environments, eliminating the risk of electrical signal leakage and resulting in a low error rate in the monitoring data. The long-term accumulated monitoring data can provide data support for the optimized design of pipeline insulation structures and the formulation of maintenance cycles, reducing the risk of unplanned downtime.

[0065] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A multi-layer protective structure for high-temperature and high-pressure pipelines in thermal power plants, characterized in that, It includes a basic module (1), an installation module (2), a buffer and anti-collision module (3), and a support and adjustment module (4); The basic module (1) includes an inner shell (11), the outer side of which is covered with a high-temperature resistant insulation layer (12), the outer side of which is covered with a vapor barrier and water barrier layer (13), the outer side of which is covered with a middle insulation filling layer (14), and the outer side of which is covered with an auxiliary vapor barrier layer (15). The installation module (2) is fitted on the outside of the auxiliary vapor barrier (15) and is used to connect with adjacent pipelines; The buffer anti-collision module (3) is set between the auxiliary vapor barrier layer (15) and the installation module (2) to provide buffer protection for the inner shell (11); The support adjustment module (4) is located on the outside of the installation module (2) and is used to support the installation module (2).

2. The multi-layer protective structure for high-temperature and high-pressure pipelines in thermal power plants according to claim 1, characterized in that, The high-temperature resistant insulation layer (12) is a high-density, high-purity alumina ceramic fiber blanket, the middle insulation filling layer (14) is a medium-density aluminum silicate fiber layer, and the vapor barrier and water barrier layer (13) and the auxiliary vapor barrier layer (15) are both nano-aluminum foil composite polytetrafluoroethylene vapor barrier membranes.

3. The multi-layer protective structure for high-temperature and high-pressure pipelines in thermal power plants according to claim 1, characterized in that, The installation module (2) includes an outer shell (21) concentrically arranged with the inner shell (11). A sleeve (22) is fixedly connected to one end of the outer shell (21). A plurality of limiting protrusions (23) are fixedly connected to the inner side of the sleeve (22) at equal intervals along its axial direction. A fixing ring (24) is fixedly connected to the other end of the outer shell (21). The outer wall of the fixing ring (24) has a plurality of annular grooves (25) corresponding one-to-one with the limiting protrusions (23).

4. The multi-layer protective structure for high-temperature and high-pressure pipelines in thermal power plants according to claim 3, characterized in that, The limiting protrusion (23) has a trapezoidal cross section, and the annular groove (25) is a trapezoidal groove. The limiting protrusion (23) of the two outer shells (21) of the adjacent pipes are in clearance fit with the annular groove (25).

5. A multi-layer protective structure for high-temperature and high-pressure pipelines in thermal power plants according to claim 4, characterized in that, The contact surfaces of the limiting protrusion (23) and the annular groove (25) are coated with high-temperature acid and alkali resistant sealant to form a multi-level bent labyrinth seepage prevention channel.

6. A multi-layer protective structure for high-temperature and high-pressure pipelines in thermal power plants according to claim 3, characterized in that, The buffer anti-collision module (3) includes a first support ring (31) sleeved on the outside of the auxiliary vapor barrier (15), and a second support ring (32) sleeved on the outside of the first support ring (31) and concentrically arranged and in contact with the inner wall of the outer shell (21). A number of reinforcing ribs (33) arranged in a circular array are fixedly connected between the second support ring (32) and the first support ring (31), and a buffer felt (34) is filled between two adjacent reinforcing ribs (33).

7. A multi-layer protective structure for high-temperature and high-pressure pipelines in thermal power plants according to claim 6, characterized in that, The reinforcing rib (33) is a triangular radial support rib, and the buffer felt (34) is an alkali-free high-resilience ceramic fiber felt that fills the gaps in the reinforcing rib (33) to absorb the stress of cold and heat deformation during unit start-up and shutdown and the vibration of pipeline operation.

8. A multi-layer protective structure for high-temperature and high-pressure pipelines in thermal power plants according to claim 6, characterized in that, The support adjustment module (4) includes a movable ring (41) sleeved on the outside of the outer shell (21). The inner wall of the movable ring (41) is fixedly connected with a number of sliders (42) arranged in a ring. The outer wall of the outer shell (21) is provided with a number of movable grooves (43) that slide with the sliders (42). The inner walls of the two movable grooves (43) at the front and rear ends of the outer shell (21) are provided with a number of positioning holes (45) that are equidistantly distributed along their length direction. The front and rear ends of the movable ring (41) are provided with positioning elements (44) for fixing with the positioning holes (45).

9. A multi-layer protective structure for high-temperature and high-pressure pipelines in thermal power plants according to claim 8, characterized in that, The positioning component (44) includes a sleeve (441) fixedly connected to the outside of the movable ring (41). A positioning rod (442) is slidably connected to the inner side of the sleeve (441) and passes through the sleeve (441). A pull block (443) is fixedly connected to one end of the positioning rod (442). The other end of the positioning rod (442) is slidably engaged with a corresponding positioning hole (45). A guide block (444) is fixedly connected to the middle of the positioning rod (442). The guide block (444) is slidably connected to the inner wall of the sleeve (441). A return spring (445) is sleeved on the inner side of the sleeve (441). The two ends of the return spring (445) abut against the inner wall of the sleeve (441) and the guide block (444), respectively.

10. A multi-layer protective structure for high-temperature and high-pressure pipelines in thermal power plants according to claim 9, characterized in that, The outer shell (21) is provided with an optical fiber monitoring module (5). The optical fiber monitoring module (5) includes an optical fiber lead connector (51) fixedly connected to the outer wall of the outer shell (21). The input end of the optical fiber lead connector (51) is connected to multiple sets of fiber optic grating sensing cables for detecting temperature, humidity and strain. The multiple sets of fiber optic grating sensing cables are respectively buried in the high temperature insulation layer (12), the vapor barrier and water barrier layer (13), the middle insulation filling layer (14), and the auxiliary vapor barrier layer (15). The output end of the optical fiber lead connector (51) is connected to a wire (52). The output end of the wire (52) is electrically connected to a signal demodulation terminal (53).

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