Steam heating device for ignition of thermal power plant boiler

Abstract

The invention discloses a steam heating device for ignition of a thermal power plant boiler, and relates to the field of boiler preheating, the steam heating device comprises a preheating box communicated with a filter flue, the preheating box comprises a hollow box body with an upper opening and a lower opening, and two connecting covers respectively connected to the upper opening end and the lower opening end of the box body; the multiple supporting frames are arranged in the box body at equal intervals, and the two ends of the multiple supporting frames are fixedly connected with the side walls of the two ends in the box body through welding; and the multiple sets of heat exchange assemblies are arranged in the length direction of the supporting frame at equal intervals. By arranging the high-temperature steam inlet pipeline communicated with the adjacent machine high-temperature steam pipeline and the preheating box structure used for flue gas waste heat recovery, dual-mode operation that steam heating is adopted in the ignition starting stage of the boiler and the normal operation stage is switched into flue gas heating can be achieved, equipment idling is avoided, and the equipment utilization rate is increased.

Description

Technical Field

[0001] This invention relates to the field of boiler preheating, specifically a steam heating device for ignition of a thermal power plant boiler. Background Technology

[0002] During the ignition and startup phase of a thermal power plant boiler, the furnace temperature typically needs to be raised above the ignition temperature of pulverized coal. Current technologies often employ preheating by heating air with steam from adjacent units; however, traditional steam heating devices suffer from low heat exchange efficiency, large footprint, and limited functionality. Furthermore, existing air preheaters and steam-heated air heaters are usually installed independently, resulting in high initial investment costs, and the steam heating devices are easily idled after the boiler is in normal operation. Some solutions utilize waste heat recovery from flue gas, but these struggle to meet the dual operational requirements of both the startup and normal operation phases. Summary of the Invention

[0003] The purpose of this invention is to provide a steam heating device for ignition of boilers in thermal power plants, in order to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a steam heating device for ignition of a boiler in a thermal power plant, comprising a preheating box connected to a filter flue, wherein the preheating box comprises a hollow box body with upper and lower openings, and two connecting covers respectively connected to the upper and lower openings of the box body; Multiple support frames are arranged equidistantly inside the box, and the two ends of the multiple support frames are respectively fixedly connected to the two end side walls inside the box by welding. Multiple heat exchange components are arranged equidistantly along the length of the support frame in a serpentine configuration. Each heat exchange component includes an outer tube, inside which is an inner tube. The outer wall of the inner tube is wound with spiral blades, which are located between the inner cavity of the outer tube and the outer wall of the inner tube to form a spiral channel for preheating air to be transported and exchanged. One end of the outer tube is connected to an air inlet pipe, and the other end is connected to an air outlet pipe. The air inlet pipe and the air outlet pipe are respectively connected to the two ends of the spiral channel.

[0005] As a further embodiment of the present invention: the input ends of the multiple air inlet pipes are all connected to the preheating air inlet pipe, and the input end of the preheating air inlet pipe is connected to an external air pump. The output ends of the multiple air outlet pipes are all connected to the preheated air outlet pipe. The output end of the preheated air outlet pipe delivers part of the preheated air to the coal mill in the power generation system to carry coal powder to form an air-coal mixture, and then sends it to the burner nozzle through the pipeline. The input ends of the multiple inner tubes are all connected to the high-temperature steam inlet pipe, the input end of the high-temperature steam inlet pipe is connected to the high-temperature steam pipe in the adjacent boiler unit, and a first valve is installed between the input end of the high-temperature steam inlet pipe and the high-temperature steam pipe in the adjacent boiler unit. The output ends of the multiple inner tubes are all connected to the high-temperature steam outlet pipeline, and the output end of the high-temperature steam outlet pipeline is connected to the lower header at the lower end of the boiler water-cooled wall. A second valve is installed between the high-temperature steam outlet pipeline and the lower header.

[0006] As a further embodiment of the present invention: the spiral blade is fixedly connected to the outer wall of the inner tube by welding, and the gap between the spiral blade and the outer tube is δ=8-15mm, and the pitch P of the spiral blade is (6-16)×δ, so as to adapt to the heat exchange requirements under different flow rates.

[0007] As a further embodiment of the present invention: a high-temperature resistant sealing ring is provided between the two ends of the outer tube and the connection of the inner tube. The outer tube is composed of two shells that are set in half, with a high-temperature resistant sealing gasket between the two shells, and the two shells are fixed together by bolts to form the outer tube.

[0008] As a further embodiment of the present invention: a dust removal assembly for cleaning the outer walls of multiple heat exchange components is provided below the support frame. The dust removal assembly includes multiple air pipes with one end closed. The multiple air pipes are arranged at equal intervals inside the box. The two ends of the air pipes are respectively rotatably connected to the inner walls of the two ends of the box through bearings. Multiple air holes are opened on both sides of the outer wall of the air pipes at equal intervals. A cleaning pipe is installed on the outside of the opening end of the trachea, and the opening end of the trachea and the cleaning pipe are rotatably connected by a rotating joint.

[0009] As a further embodiment of the present invention: the input end of the ash removal pipeline is connected to the high-temperature steam outlet pipeline, and a third valve is installed between the ash removal pipeline and the high-temperature steam outlet pipeline.

[0010] As a further embodiment of the present invention: a connecting pipe is provided between the preheated air inlet pipe and the high-temperature steam inlet pipe, and a fourth valve is installed at the connection between the connecting pipe and the high-temperature steam inlet pipe.

[0011] As a further embodiment of the present invention: a drive assembly is installed between the multiple air tubes, the drive assembly includes a motor, the motor is rotatably connected to the housing via a shaft and bearings, and a drive gear is installed at the output end of the motor; One end of each of the multiple air tubes is fixedly connected to a driven gear, and the multiple driven gears mesh in a linear sequence, with one of the driven gears meshing with the motor.

[0012] As a further embodiment of the present invention: the high-temperature steam inlet pipe and the preheating air inlet pipe are distributed opposite to each other on both sides of the preheating box.

[0013] As a further embodiment of the present invention: multiple first strip-shaped grooves are formed on the two opposing side walls of the housing, and the two ends of the air inlet pipe, air outlet pipe and inner pipe respectively overlap the bottom of the corresponding first strip-shaped groove; multiple second strip-shaped grooves are formed at the lower end of the side wall, which are symmetrically matched with the two sets of first strip-shaped grooves on the upper and lower sides, and the tops of the multiple second strip-shaped grooves respectively contact the two ends of the air inlet pipe, air outlet pipe and inner pipe; high-temperature resistant sealing gaskets are provided on the inner walls of the first strip-shaped grooves and the second strip-shaped grooves.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. By setting up a high-temperature steam inlet pipeline connected to the high-temperature steam pipeline of the adjacent unit, and a preheating box structure for flue gas waste heat recovery, the boiler can achieve dual-mode operation, using steam heating during the ignition and start-up phase and switching to flue gas heating during normal operation, thus avoiding equipment idleness and improving equipment utilization. 2. The heat exchange component adopts a sleeve-type structure, with spiral blades wound around the outer wall of the inner tube to form a spiral channel, which extends the flow path of the preheating air, increases airflow disturbance, and significantly improves the heat exchange efficiency between steam and air; at the same time, an expansion gap is reserved between the spiral blades and the outer tube to adapt to the thermal expansion requirements under high temperature conditions. 3. The preheated air outlet pipeline delivers part of the heated hot air to the coal mill to carry the pulverized coal, and the high-temperature steam outlet pipeline delivers the exhaust steam to the lower header to heat the boiler water, realizing the cascade utilization of thermal energy; at the same time, cold air is introduced by utilizing the original steam channel, and the ash removal component is used to blow the outer wall of the heat exchange component to ensure the heat exchange efficiency under long-term operation. 4. The side wall of the enclosure is provided with a strip groove, through which the heat exchange components are installed by overlapping. Combined with the split external pipe design, this facilitates the disassembly, maintenance and replacement of the heat exchange components. 5. By setting up connecting pipelines and multiple valves, a smooth switching between steam heating and flue gas heating can be achieved, ensuring stable air temperature during boiler startup. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is another perspective of the present invention; Figure 3 This is a schematic diagram of the disassembled structure of the present invention; Figure 4 This is a schematic diagram of the connection structure between the heat exchange component and each pipeline of the present invention; Figure 5This is a schematic diagram of the installation structure of the dust removal component and the drive component of the present invention; Figure 6 This is a schematic diagram of the heat exchange component of the present invention; Figure 7 This is a disassembled structural entity of the heat exchange component of the present invention; Figure 8 This is a schematic diagram of the internal planar structure of the heat exchange component of the present invention.

[0016] In the diagram: 1. Preheating box; 101. Box body; 102. First strip groove; 103. Side wall; 104. Second strip groove; 105. Connecting cover; 2. Support frame; 3. Heat exchange assembly; 31. Air inlet pipe; 32. Air outlet pipe; 301. Outer pipe; 302. Inner pipe; 303. Spiral blade; 304. High-temperature resistant sealing gasket; 4. Preheating air inlet pipe; 5. Preheating air outlet pipe; 6. High-temperature steam inlet pipe; 61. First valve; 7. High-temperature steam outlet pipe; 71. Second valve; 8. Dust removal assembly; 81. Third valve; 801. Air pipe; 802. Air hole; 803. Dust removal pipe; 804. Rotary joint; 9. Connecting pipe; 91. Fourth valve; 10. Drive assembly; 1001. Motor; 1002. Drive gear; 1003. Driven gear. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Please see Figures 1-5 In this embodiment of the invention, a steam heating device for ignition of a thermal power plant boiler includes a preheating box 1 connected to a filter flue. The preheating box 1 includes a hollow box body 101 with upper and lower openings, and two connecting covers 105 respectively connected to the upper and lower openings of the box body 101.

[0019] Multiple support frames 2 are arranged at equal intervals inside the housing 101, and the two ends of the multiple support frames 2 are respectively fixedly connected to the two side walls inside the housing 101 by welding.

[0020] Multiple heat exchange components 3 are arranged at equal intervals along the length of the support frame 2. The heat exchange components 3 are arranged in a serpentine pattern. Each heat exchange component 3 includes an outer tube 301, an inner tube 302 wrapped inside the outer tube 301, and spiral blades 303 wound around the outer wall of the inner tube 302. The spiral blades 303 are located between the inner cavity of the outer tube 301 and the outer wall of the inner tube 302 to form a spiral channel for preheating air to be transported and exchanged. An air inlet pipe 31 is connected to the outer wall of one end of the outer tube 301, and an air outlet pipe 32 is connected to the outer wall of the other end of the outer tube 301. The air inlet pipe 31 and the air outlet pipe 32 are respectively connected to the two ends of the spiral channel.

[0021] The input ends of multiple air inlet pipes 31 are all connected to the preheated air inlet pipe 4, and the input end of the preheated air inlet pipe 4 is connected to an external air pump.

[0022] The output ends of multiple air outlet pipes 32 are all connected to the preheated air outlet pipe 5. The output end of the preheated air outlet pipe 5 delivers part of the preheated air to the coal mill in the power generation system to carry coal powder to form an air-coal mixture, and then sends it to the burner nozzle through the pipeline.

[0023] The input ends of multiple inner pipes 302 are all connected to the high-temperature steam inlet pipe 6. The input end of the high-temperature steam inlet pipe 6 is connected to the high-temperature steam pipe in the adjacent unit boiler. A first valve 61 is installed between the input end of the high-temperature steam inlet pipe 6 and the high-temperature steam pipe in the adjacent unit boiler.

[0024] The output ends of multiple inner pipes 302 are all connected to the high-temperature steam outlet pipe 7. The output end of the high-temperature steam outlet pipe 7 is connected to the lower header at the lower end of the boiler water-cooled wall. A second valve 71 is installed between the high-temperature steam outlet pipe 7 and the lower header.

[0025] In this embodiment, a dual-condition, dual-heat-source, shell-and-tube spiral fin heat exchanger structure solves the problem of switching between relying on adjacent unit steam during boiler startup and utilizing waste heat from flue gas during normal operation. This achieves dual-purpose operation: steam during startup and flue gas during normal operation, avoiding equipment idleness. It can replace the combination of air preheater and independent steam-air heater in existing thermal power plant boilers, reducing the equipment's footprint and investment costs. The unique structural design of heat exchange component 3 extends the flow channel, increases turbulence, and improves the heat exchange rate between steam and air.

[0026] Flue gas enters the housing through the upper connecting hood, and after horizontally washing the outer wall of the outer tubes of multiple heat exchange components from top to bottom, it is discharged through the lower connecting hood.

[0027] Before the boiler in a thermal power plant is ignited, it needs to borrow steam from a neighboring unit. The steam from the neighboring unit is introduced into the high-temperature steam inlet pipe 6, and then the high-temperature steam inlet pipe 6 delivers the high-temperature hot steam to each outer pipe 301. It should be noted that before this, cold air is first delivered into the preheating air inlet pipe 4. The cold air flows in the spiral channel of the heat exchange component 3 for a period of time before passing through the high-temperature steam. The high-temperature steam transfers heat to the cold air in the spiral channel through the outer wall of the inner pipe 302 and the spiral blades 303. The cold air flows in the spiral channel. Due to the structural characteristics of the spiral channel, it can effectively increase the turbulence of the cold air, which is conducive to the heat exchange between the steam and the cold air.

[0028] After heat exchange with the cold air, the steam enters the high-temperature steam outlet pipe 7. The exhaust steam can be injected into the lower header through heating nozzles arranged inside or at the bottom via the high-temperature steam outlet pipe 7. The steam is injected at high speed into the water at the bottom of the lower header. The water in the lower header is heated, its density decreases, and it flows upwards along the water-cooled wall tubes (entering the steam drum). Meanwhile, the water in the steam drum, which is relatively cooler and denser, flows back to the lower header through the downcomer. This forms a natural circulation, gradually and evenly raising the water temperature of the entire boiler.

[0029] The heated cold air will become hot air with a certain temperature. Part of this hot air is introduced into the boiler chamber for heating (that is, secondary air in the prior art), and part of it is introduced into the coal mill to blow coal powder out of the coal mill and transport it into the boiler chamber (that is, secondary air in the prior art).

[0030] Once the boiler is running normally and the flue gas temperature reaches the set value (e.g., 300℃) and stabilizes, gradually close the steam valves while ensuring that the cold air outlet temperature does not drop before completely shutting off the steam. During the switching process, consider supplying steam and flue gas in parallel for a period of time to achieve a smooth transition.

[0031] Please refer to this carefully. Figures 1 to 8 Below the support frame 2 is a dust removal assembly 8 for cleaning the outer walls of multiple heat exchange components 3. The dust removal assembly 8 includes multiple air pipes 801 with one end closed. The multiple air pipes 801 are arranged at equal intervals inside the housing 101. The two ends of the air pipes 801 are rotatably connected to the inner walls of the two ends of the housing 101 through bearings. Multiple air holes 802 are opened on both sides of the outer wall of the air pipes 801.

[0032] A cleaning pipe 803 is installed on the outside of the opening end of the trachea 801, and the opening end of the trachea 801 and the cleaning pipe 803 are rotatably connected by a rotating joint 804.

[0033] The inlet of the cleaning pipe 803 is connected to the high-temperature steam outlet pipe 7, and a third valve 81 is installed between the cleaning pipe 803 and the high-temperature steam outlet pipe 7.

[0034] A connecting pipe 9 is provided between the preheated air inlet pipe 4 and the high-temperature steam inlet pipe 6, and a fourth valve 91 is installed at the connection between the connecting pipe 9 and the high-temperature steam inlet pipe 6.

[0035] A drive assembly 10 is installed between multiple air tubes 801. The drive assembly 10 includes a motor 1001. The motor 1001 is rotatably connected to the housing 101 via a shaft and bearings. An active gear 1002 is installed at the output end of the motor 1001.

[0036] One end of each of the multiple air tubes 801 is fixedly connected to a driven gear 1003, and the multiple driven gears 1003 mesh with each other in a linear sequence. One of the driven gears 1003 meshes with the motor 1001.

[0037] In this embodiment: after the flue gas is fully used to heat the cold air, in order to avoid the inner cavity of the inner tube 302 being without a medium, this solution can open the fourth valve 91, thereby connecting the connecting pipe 9 with the preheating air inlet pipe 4. The cold air will enter the high-temperature steam inlet pipe 6 through the connecting pipe 9, and then flow into the inner tube 302 through the high-temperature steam inlet pipe 6 for heat exchange. Finally, it will flow out through the high-temperature steam outlet pipe 7 and be transported to the dust removal component 8. Since the air pipe 801 will rotate under the driving action of the driving component 10, multiple rotating air pipes 801 will spray airflow through the air holes 802 to sweep the outer wall of multiple heat exchange components 3, so as to reduce the dust covering the outer wall of the heat exchange components 3 and affect heat conduction.

[0038] This solution utilizes the original steam flow channel to channel cold air, which not only avoids long-term voids in the inner tube 302 that could damage the inner wall of the inner tube 302, but also uses heated air to purge the outer wall of the heat exchange component 3, so that the heat exchange component 3 can maintain good heat conduction effect during continuous operation. At the same time, the purging air has a certain temperature and will not reduce the flue temperature.

[0039] Please refer to this carefully. Figures 1 to 8 The spiral blade 303 is fixedly connected to the outer wall of the inner tube 302 by welding, and the gap between the spiral blade 303 and the outer tube 301 is δ=8-15mm. The pitch P of the spiral blade 303 is (6-16)×δ to adapt to the heat exchange requirements under different flow rates.

[0040] High-temperature resistant sealing rings are provided at the connection points between the two ends of the outer tube 301 and the inner tube 302. The outer tube 301 is composed of two shells that are set in half. A high-temperature resistant sealing gasket 304 is placed between the two shells, and the two shells are fixed together by bolts to form the outer tube 301.

[0041] In this embodiment, a certain gap is left between the outer tube 301 and the spiral blade 303 to allow for thermal expansion of the outer tube 301 and the spiral blade 303.

[0042] The final determination of the gap should be subject to the flow rate design.

[0043] For the cold air side, the recommended economic flow rate is v = 12-18 m / s.

[0044] The gap can be calculated using the formula: δ=3600·v·π·Dm\Q; Q: Cooling air volumetric flow rate (m³ / h); v: Design flow velocity (take 12-18 m / s); Dm: The average diameter of the spiral channel (approximately equal to the outer diameter of the inner tube, Do + δ). Since δ appears on both sides of the equation, we usually first estimate a value of δ, calculate Dm and flow velocity, and then check whether the flow velocity is within the recommended range. Iteration 1-2 times is sufficient to determine the result.

[0045] Please refer to this carefully. Figures 1 to 8 The high-temperature steam inlet pipe 6 and the preheating air inlet pipe 4 are distributed opposite to each other on both sides of the preheating box 1.

[0046] In this embodiment: In order to ensure that the heat of the steam can be absorbed by the cold air to the maximum extent, the steam flow direction in this scheme is opposite to the cold air flow direction, so that the average temperature difference between the two is the largest and the heat exchange efficiency is the highest.

[0047] Please refer to this carefully. Figures 1 to 8 Multiple first strip grooves 102 are provided on the two opposite side walls of the housing 101. The two ends of the air inlet pipe 31, the air outlet pipe 32 and the inner pipe 302 are respectively connected to the bottom of the corresponding first strip groove 102. Multiple second strip grooves 104 are provided at the lower end of the side wall 103, which are symmetrically matched with the two sets of first strip grooves 102. The tops of the multiple second strip grooves 104 respectively contact the two ends of the air inlet pipe 31, the air outlet pipe 32 and the inner pipe 302. High temperature resistant sealing gaskets are provided on the inner walls of the first strip grooves 102 and the second strip grooves 104.

[0048] In this embodiment, by designing the box 101, the first strip groove 102, the side wall 103, the second strip groove 104, and the connecting cover 105 into a modular structure, it is easy to disassemble and assemble the preheating box 1 in the later stage, thereby facilitating the subsequent maintenance and replacement of the heat exchange component 3.

[0049] The second strip groove 104 is detachably connected to the side wall 103 by bolts, and presses the two ends of the air inlet pipe, air outlet pipe and inner pipe into the first strip groove, and achieves sealing with the high temperature resistant sealing gasket.

[0050] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A steam heating device for ignition of a boiler in a thermal power plant, characterized in that, include: A preheating box (1) connected to the filter flue includes a box body (101) with upper and lower openings and two connecting covers (105) respectively connected to the upper and lower openings of the box body (101). Multiple support frames (2) are arranged at equal intervals inside the box (101), and the two ends of the multiple support frames (2) are respectively fixedly connected to the two end side walls inside the box (101) by welding. Multiple heat exchange components (3) are arranged at equal intervals along the length of the support frame (2). The heat exchange components (3) are arranged in a serpentine pattern. Each heat exchange component (3) includes an outer tube (301) and an inner tube (302) inside the outer tube (301). The outer wall of the inner tube (302) is wound with spiral blades (303). The spiral blades (303) are located between the inner cavity of the outer tube (301) and the outer wall of the inner tube (302) to form a spiral channel for preheating air to be transported and exchanged. One end of the outer wall of the outer tube (301) is connected to an air inlet pipe (31), and the other end of the outer tube (301) is connected to an air outlet pipe (32). The air inlet pipe (31) and the air outlet pipe (32) are respectively connected to the two ends of the spiral channel.

2. The steam heating device for ignition of a thermal power plant boiler according to claim 1, characterized in that, The input ends of the multiple air inlet pipes (31) are all connected to the preheated air inlet pipe (4), and the input end of the preheated air inlet pipe (4) is connected to an external air pump. The output ends of the multiple air outlet pipes (32) are all connected to the preheated air outlet pipe (5). The output end of the preheated air outlet pipe (5) delivers part of the preheated air to the coal mill in the power generation system to carry coal powder to form an air-coal mixture, and sends it to the burner nozzle through the pipe. The input ends of the multiple inner tubes (302) are all connected to the high-temperature steam inlet pipe (6), the input end of the high-temperature steam inlet pipe (6) is connected to the high-temperature steam pipe in the adjacent unit boiler, and a first valve (61) is installed between the input end of the high-temperature steam inlet pipe (6) and the high-temperature steam pipe in the adjacent unit boiler. The output ends of the multiple inner tubes (302) are all connected to the high-temperature steam outlet pipe (7). The output end of the high-temperature steam outlet pipe (7) is connected to the lower header at the lower end of the boiler water-cooled wall. A second valve (71) is installed between the high-temperature steam outlet pipe (7) and the lower header.

3. A steam heating device for ignition of a thermal power plant boiler according to claim 2, characterized in that, The spiral blade (303) is fixedly connected to the outer wall of the inner tube (302) by welding, and the gap between the spiral blade (303) and the outer tube (301) is δ=8-15mm, and the pitch P of the spiral blade (303) is (6-16)×δ.

4. A steam heating device for ignition of a thermal power plant boiler according to claim 3, characterized in that, High-temperature resistant sealing rings are provided at the connection points between the two ends of the outer tube (301) and the inner tube (302). The outer tube (301) is composed of two shells that are set in half. A high-temperature resistant sealing gasket (304) is placed between the two shells, and the two shells are fixed together by bolts to form the outer tube (301).

5. A steam heating device for ignition of a thermal power plant boiler according to claim 4, characterized in that, Below the support frame (2) is a cleaning assembly (8) for cleaning the outer walls of multiple heat exchange components (3). The cleaning assembly (8) includes multiple air pipes (801) with one end closed. The multiple air pipes (801) are arranged at equal intervals inside the box (101). The two ends of the air pipes (801) are respectively rotatably connected to the inner walls of the two ends of the box (101) through bearings. Multiple air holes (802) are opened on both sides of the outer wall of the air pipes (801). A cleaning pipe (803) is installed on the outside of the opening end of the air pipe (801), and the opening end of the air pipe (801) and the cleaning pipe (803) are rotatably connected by a rotating joint (804).

6. A steam heating device for ignition of a thermal power plant boiler according to claim 5, characterized in that, The input end of the cleaning pipe (803) is connected to the high-temperature steam outlet pipe (7), and a third valve (81) is installed between the cleaning pipe (803) and the high-temperature steam outlet pipe (7).

7. A steam heating device for ignition of a thermal power plant boiler according to claim 6, characterized in that, A connecting pipe (9) is provided between the preheated air inlet pipe (4) and the high-temperature steam inlet pipe (6), and a fourth valve (91) is installed at the connection between the connecting pipe (9) and the high-temperature steam inlet pipe (6).

8. A steam heating device for ignition of a thermal power plant boiler according to claim 7, characterized in that, A drive assembly (10) is installed between the multiple air tubes (801). The drive assembly (10) includes a motor (1001). The motor (1001) is rotatably connected to the housing (101) via a shaft and bearings. A drive gear (1002) is installed at the output end of the motor (1001). One end of each of the multiple air pipes (801) is fixedly connected to a driven gear (1003), and the multiple driven gears (1003) mesh in a linear sequence, with one of the driven gears (1003) meshing with the motor (1001).

9. A steam heating device for ignition of a thermal power plant boiler according to claim 8, characterized in that, The high-temperature steam inlet pipe (6) and the preheating air inlet pipe (4) are distributed opposite to each other on both sides of the preheating box (1).

10. A steam heating device for ignition of a thermal power plant boiler according to claim 9, characterized in that, Multiple first strip grooves (102) are provided on the two opposing side walls of the housing (101). The two ends of the air inlet pipe (31), air outlet pipe (32) and inner pipe (302) are respectively connected to the bottom of the corresponding first strip groove (102). Multiple second strip grooves (104) are provided at the lower end of the side wall (103) and are symmetrically matched with the two sets of first strip grooves (102). The tops of the multiple second strip grooves (104) are respectively in contact with the two ends of the air inlet pipe (31), air outlet pipe (32) and inner pipe (302). High temperature resistant sealing gaskets are provided on the inner walls of the first strip groove (102) and the second strip groove (104).

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