Slagging pipe structure of circulating fluidized bed boiler
By setting up a sealing device and metal expansion joints in the slag discharge pipe structure of the circulating fluidized bed boiler, the problem of breaking the slag discharge pipe due to excessive thermal expansion stress or causing cracking of the water-cooled wall is solved, and the long-term safe and stable operation of the slag discharge pipe and optimization of ash discharge pipe are achieved.
Patent Information
- Application Number
- CN202421847445.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-01
- Publication Date
- 2025-05-30
- Estimated Expiration
- 2034-08-01
AI Technical Summary
The existing circulating fluidized bed boiler slag discharge pipe is prone to break due to excessive thermal expansion stress or lead to cracking of the water-cooled wall in high temperature environments, and it is difficult to effectively release expansion stress, affecting the long-term, efficient and safe operation of the boiler.
A slag discharge tube structure including a membrane-type water-cooled wall, a slag discharge tube and a metal expansion joint is designed. By setting a via hole at the bottom of the air chamber, the lower end of the slag discharge tube passes through the via hole, and a primary sealing device and a secondary sealing device are provided to ensure that the slag discharge tube can expand freely at both high and normal temperature parts, and effectively prevent the ash from ejecting.
Effectively absorb the thermal expansion stress of the slag discharge pipe, avoid fractures and water-cooled wall cracking problems, and at the same time optimize the ash discharge environment, extend the service life of the metal expansion joints, and ensure the long-term safe and stable operation of the slag discharge pipe.
Smart Images
Figure CN222925491U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a slag discharge pipe structure, in particular to a slag discharge pipe structure for a circulating fluidized bed boiler, belonging to the technical field of slag discharge devices for circulating fluidized bed boilers. Background Art
[0002] A circulating fluidized bed boiler usually consists of a combustion system, a gas-solid separation and return device, a tail convection flue, and auxiliary equipment. Among them, the combustion system is an important part of the circulating fluidized bed boiler. Main operation monitoring parameters such as bed temperature, material layer differential pressure, and furnace negative pressure are all reflected in the boiler combustion system. The adjustment of the combustion system is crucial for the safety, economy, and environmental protection of the entire boiler operation, and its role is very prominent; the combustion system mainly includes a furnace, a combustion chamber, a wind distribution plate and a primary air chamber, a slag discharge device, and other parts.
[0003] The most important component of the slag discharge device is the slag discharge pipe. By adjusting the slag discharge, the solid bed layer of the boiler is maintained at an appropriate height, the material circulation is effectively controlled, and the material layer differential pressure is controlled within a reasonable range, making the combustion reaction more complete and improving the boiler thermal efficiency. Through the slag discharge work, impurities and harmful substances in the bed layer can also be regularly cleaned to avoid problems such as blockage, coking, and corrosion in the bed layer. Therefore, the normal operation of the slag discharge pipe is crucial for the stable combustion of the boiler, and the structural form of the slag discharge pipe also determines whether the slag discharge work of the boiler can be carried out safely and stably for a long time.
[0004] The existing slag discharge method is that the slag discharge pipe passes through the bottom plate of the air chamber as a whole and then discharges slag. The lower end of the slag discharge pipe extends out of the air chamber and is connected to a slag discharge valve. When slag discharge is required, the slag discharge valve is opened, and the ash slag is discharged from the bottom of the furnace through the slag discharge pipe. The upper end of the slag discharge pipe is connected to the slag discharge port on the wind distribution plate in the furnace, and the lower part of the slag discharge pipe is welded tightly to the water-cooled wall of the primary air chamber, aiming to prevent slag leakage and slag spraying problems at the contact between the lower part of the slag discharge pipe and the water-cooled wall of the primary air chamber. Since the temperature of the furnace slag is mostly above 800°C, it will cause a large axial displacement of the slag discharge pipe. Although the fixed connection solves the problems of slag leakage and slag spraying, it restricts the thermal expansion of the slag discharge pipe. When the expansion force exceeds the stress limit of the slag discharge pipe itself, cracks will appear at the weak parts of the pipe, and then the entire slag pipe will break; or when the expansion stress of the slag discharge pipe cannot be completely released, it will cause an impact on the welded parts of the slag discharge pipe, resulting in the tearing of the welded joint of the water-cooled wall of the primary air chamber and the leakage of the water-cooled wall of the primary air chamber.
[0005] For this reason, some improvements have been made to the structural form of the slag discharge pipe in the prior art, and a metal expansion joint has been designed at the slag discharge pipe: some metal expansion joints are designed separately in the primary air chamber, and some metal expansion joints are designed separately outside the primary air chamber. The metal expansion joint is designed in the primary air chamber, and the expansion joint can effectively absorb the thermal expansion of the slag discharge pipe, and solve the problem of fracture and cracking caused by the expansion of the slag discharge pipe. However, the temperature in the primary air chamber is much higher than the ambient temperature. The long-term high temperature and the harsh environment such as the ash leaking into the primary air chamber will have a serious impact on the corrugated part of the expansion joint, which is easy to cause residual deformation of the elastic element of the expansion joint, seriously affecting the service life and safety of the expansion joint; while the metal expansion joint is designed outside the primary air chamber, so that the slag discharge pipe can slide relative to the water-cooled wall of the primary air chamber, which also solves the problem caused by the expansion of the slag discharge pipe, but the ash leaking into the primary air chamber will accumulate at the sliding contact point, causing blockage, causing the slag discharge pipe to get stuck when sliding relative to the water-cooled wall of the primary air chamber, limiting the free expansion of the slag pipe, and the expansion stress cannot be fully released, and stress damage will still occur, affecting the long-term, efficient and safe operation of the boiler. Summary of the invention
[0006] The utility model aims to overcome the deficiencies of the prior art and provide a slag discharge pipe structure for a circulating fluidized bed boiler to solve the problems existing in the background technology.
[0007] The technical solution adopted by the utility model to achieve the above-mentioned purpose is:
[0008] A slag discharge pipe structure for a circulating fluidized bed boiler comprises a wind chamber composed of a membrane water-cooled wall, a slag discharge pipe and a metal expansion joint, the top wall of the wind chamber is an air distribution plate, the upper end of the slag discharge pipe is connected to the air distribution plate, and the lower end of the slag discharge pipe extends out of the wind chamber, and is characterized in that: a through hole is provided on the bottom wall of the wind chamber, and the lower end of the slag discharge pipe passes through the through hole and extends out of the wind chamber; a primary sealing device is provided between the upper part of the through hole, the slag discharge pipe and the wind chamber water-cooled wall, and a secondary sealing device is provided between the lower part of the through hole, the slag discharge pipe and the wind chamber water-cooled wall.
[0009] By adopting the above technical solution, sealing devices are provided in the high-temperature part of the slag discharge pipe (inside the primary air chamber) and the normal-temperature part of the slag discharge pipe (outside the primary air chamber), which not only ensures that the thermal expansion of the slag discharge pipe can be effectively absorbed, but also solves the problem that the thermal expansion stress of the slag pipe cannot be fully released, causing the slag pipe to break and the primary air chamber water-cooled wall to crack. It also effectively prevents the ash in the primary air chamber from spraying out from the slag discharge pipe, eliminates the problems of slag leakage and slag spraying, and optimizes the working environment of ash discharge.
[0010] In the above-mentioned slag discharge pipe structure for a circulating fluidized bed boiler, the slag discharge pipe can slide in the through hole.
[0011] In the above-mentioned slag discharge pipe structure of a circulating fluidized bed boiler, the primary sealing device includes an inner sleeve, an outer sleeve and a sealing ring. The lower end of the inner sleeve is fixedly connected to the bottom wall of the air chamber. The inner hole of the sealing ring is fixedly connected to the outer side surface of the slag discharge pipe. The upper end of the outer sleeve is fixedly connected to the outer side surface of the sealing ring. The lower end of the outer sleeve is higher than the bottom wall of the air chamber. The upper end of the inner sleeve is higher than the lower end of the outer sleeve. The inner diameter of the inner sleeve is larger than the outer diameter of the slag discharge pipe, and the inner diameter of the outer sleeve is larger than the inner diameter of the inner sleeve.
[0012] By adopting the above technical solution, the inner sleeve and the outer sleeve form a labyrinth sealing structure, which not only ensures the free expansion of the slag discharge pipe, but also effectively prevents the ash and slag in the primary air chamber from spraying out from the slag discharge pipe, eliminating problems such as slag leakage and slag spraying.
[0013] In the above-mentioned slag discharge pipe structure of a circulating fluidized bed boiler, the secondary sealing device includes a sealing box and a metal expansion joint. The sealing box is arranged at the lower part of the air chamber. The metal expansion joint is connected to the lower part of the sealing box. The slag discharge pipe passes through the sealing box and the metal expansion joint.
[0014] Furthermore, the sealing box includes a bottom plate and four side wall plates. The four side wall plates are fixedly connected to each other. The lower ends of the four side wall plates are fixedly connected to the bottom plate. The upper ends of the four side wall plates are adapted to and fixedly connected to the outer side surface of the bottom wall of the air chamber. A vertical through hole is provided on the bottom plate. The slag discharge pipe passes through the vertical through hole and can slide in the vertical through hole.
[0015] The upper end cover of the metal expansion joint is fixedly connected to the bottom plate of the sealing box, and the lower end cover of the metal expansion joint is fixedly connected to the outer side wall of the slag discharge pipe.
[0016] Even further, the metal expansion joint and the inside of the sealing box are filled with aluminum silicate refractory fiber.
[0017] By adopting the above technical solution, the metal expansion joint is arranged outside the primary air chamber. The inside of the sealing box is filled with aluminum silicate refractory fiber. The sealing box is welded tightly to the water-cooled wall of the primary air chamber. The upper end of the expansion joint is welded tightly to the sealing box, and the lower end is welded tightly to the slag discharge pipe. The slag discharge pipe is not welded to the water-cooled wall of the primary air chamber and the secondary metal sealing box, and can maintain relative sliding. This not only ensures that the metal expansion joint is in a normal temperature working environment, prolongs the service life of the expansion joint, but also ensures that the thermal expansion of the slag pipe can be effectively absorbed, solving problems such as the thermal expansion stress of the slag pipe not being fully released, causing the fracture of the slag pipe and the tearing of the water-cooled wall of the primary air chamber. Beneficial effects
[0018] A slag discharge pipe structure of a circulating fluidized bed boiler according to the present utility model adopts a labyrinth-type high-temperature-resistant metal sealing structure in the high-temperature part of the slag discharge pipe (inside the primary air chamber). The labyrinth-type inner cavity is integrally formed by using a sleeve structure. While ensuring the free expansion of the slag discharge pipe, it effectively prevents the ash and slag in the primary air chamber from spraying out from the slag discharge pipe, eliminates problems such as slag leakage and slag spraying, and optimizes the working environment of ash and slag discharge; the normal-temperature part of the slag discharge pipe (outside the primary air chamber) adopts a secondary metal sealing box and a metal expansion joint structure. The metal expansion joint is arranged outside the primary air chamber, and the inside of the sealing box is filled with aluminum silicate refractory fiber. This not only ensures that the metal expansion joint is in a normal-temperature working environment, extends the service life of the expansion joint, but also ensures that the thermal expansion of the slag discharge pipe can be effectively absorbed, solves the problems that the thermal expansion stress of the slag discharge pipe cannot be fully released, causing the fracture of the slag discharge pipe and the tearing of the water-cooled wall of the primary air chamber. It enables the slag discharge pipe to operate safely and stably for a long time, laying a foundation for the long-term, efficient, and safe operation of the boiler. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 is the overall schematic diagram of the present utility model.
[0020] Figure 2 is Figure 1 the enlarged schematic diagram of part A in
[0021] Figure 3 is Figure 1 the enlarged schematic diagram of part B in
[0022] In the figure: 1 slag discharge pipe, 2 air chamber, 3 sealing box, 31 side wall plate, 32 bottom plate, 4 membrane water-cooled wall, 5 metal expansion joint, 6 sealing ring, 7 outer sleeve, 8 inner sleeve, 9 through hole, 10 aluminum silicate refractory fiber, 11 ash discharge port. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0023] To clearly illustrate the technical features of this solution, the present utility model will be further described below through non-limiting embodiments in combination with the drawings.
[0024] Please refer to Figures 1 to 3 , a slag discharge pipe structure of a circulating fluidized bed boiler, including an air chamber 2 composed of a membrane water-cooled wall 4, a slag discharge pipe 1, and a metal expansion joint 5. The top wall of the air chamber 2 is a wind distribution plate. The slag discharge pipe 1 is made of seamless heat-resistant steel pipe. The upper end of the slag discharge pipe 1 is fixedly connected to the wind distribution plate. The lower end of the slag discharge pipe 1 passes through a through hole 9 provided on the bottom wall of the air chamber 2 and extends out of the air chamber 2. The slag discharge pipe 1 ensures relative sliding with the water-cooled wall through hole 9 of the primary air chamber 2 and is not welded; a primary sealing device is provided between the upper part of the through hole 9, the slag discharge pipe 1 and the membrane water-cooled wall 4 of the air chamber 2, and a secondary sealing device is provided between the lower part of the through hole 9, the slag discharge pipe 1 and the membrane water-cooled wall of the air chamber 2. 2. The slag discharge pipe can slide in the through hole.
[0025] 3. Specifically, the primary sealing device includes an inner sleeve 8, an outer sleeve 7, and a sealing ring 6. The lower end of the inner sleeve 8 is fixedly welded and sealed to the bottom wall of the air chamber 2. The inner hole of the sealing ring 6 is fixedly welded and sealed to the outer side surface of the slag discharge pipe 1. The upper end of the outer sleeve 7 is fixedly welded and sealed to the outer side surface of the sealing ring 6. The lower end of the outer sleeve 7 is higher than the bottom wall of the air chamber 2, and the upper end of the inner sleeve 8 is higher than the lower end of the outer sleeve 7. The inner diameter of the inner sleeve 8 is larger than the outer diameter of the slag discharge pipe 1, and the inner diameter of the outer sleeve 7 is larger than the inner diameter of the inner sleeve 8. The slag discharge pipe 1 can slide within the inner sleeve 8, and the inner sleeve 8 can slide within the outer sleeve 7.
[0026] The secondary sealing device includes a sealing box 3 and a metal expansion joint 5. The sealing box 3 is arranged at the lower part of the air chamber 2. The metal expansion joint 5 is connected to the lower part of the sealing box 3. The slag discharge pipe 1 passes through the sealing box 3 and the metal expansion joint 5.
[0027] Specifically, the sealing box 3 includes a bottom plate 32 and four side wall plates 31. The four side wall plates 31 are fixedly welded and sealed to each other. The lower ends of the four side wall plates 31 are fixedly welded and sealed to the bottom plate 32. The upper ends of the four side wall plates 31 are adapted to the shape of the outer side surface of the bottom wall of the air chamber and are fixedly welded and sealed. The bottom plate 32 is provided with a vertical through hole, and the slag discharge pipe 1 passes through the vertical through hole and can slide within the vertical through hole.
[0028] The upper end cover of the metal expansion joint 5 is fixedly welded and sealed to the bottom plate 32 of the sealing box 3, and the lower end cover of the metal expansion joint 5 is fixedly welded and sealed to the outer side wall of the slag discharge pipe 1.
[0029] The inside of the metal expansion joint 5 and the sealing box 3 is filled with aluminum silicate refractory fiber 10.
[0030] There is an ash discharge port 11 in the air chamber 2. When the air chamber 2 leaks ash, the leaked ash in the air chamber 2 can be discharged through the ash discharge port 11.
[0031] In this embodiment, the slag discharge pipe 1, the sealing ring 6, the outer sleeve 7, and the inner sleeve 8 are all made of heat-resistant steel.
[0032] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "left", "right", "front", "rear", "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. The above terms are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.
[0033] Except for the technical features described in the specification, they are all well-known technologies to those skilled in the art.
[0034] The embodiments listed above are only for understanding the present utility model and are not limitations on the technical solutions described in the present utility model. Those of ordinary skill in the relevant art can make various changes or deformations on the basis of the technical solutions described in the claims, and all equivalent changes or deformations should be covered within the scope of protection of the claims of the present utility model.
Claims
1. A slag discharge pipe structure for a circulating fluidized bed boiler, comprising a wind chamber composed of a membrane water-cooled wall, a slag discharge pipe and a metal expansion joint, the top wall of the wind chamber is an air distribution plate, the upper end of the slag discharge pipe is connected to the air distribution plate, and the lower end of the slag discharge pipe extends out of the wind chamber, characterized in that: The bottom wall of the wind chamber is provided with a through hole, and the lower end of the slag discharge pipe passes through the through hole and extends out of the wind chamber; a primary sealing device is provided between the upper part of the through hole, the slag discharge pipe and the water-cooled wall of the wind chamber, and a secondary sealing device is provided between the lower part of the through hole, the slag discharge pipe and the water-cooled wall of the wind chamber.
2. The slag discharge pipe structure of a circulating fluidized bed boiler according to claim 1, characterized in that: The slag discharge pipe is slidably connected to the through hole.
3. The slag discharge pipe structure of a circulating fluidized bed boiler according to claim 1, characterized in that: The primary sealing device comprises an inner sleeve, an outer sleeve and a sealing ring, the lower end of the inner sleeve is fixedly connected to the bottom wall of the wind chamber, the inner hole of the sealing ring is fixedly connected to the outer side surface of the slag discharge pipe, and the upper end of the outer sleeve is fixedly connected to the outer side surface of the sealing ring; the lower end of the outer sleeve is higher than the bottom wall of the wind chamber, and the upper end of the inner sleeve is higher than the lower end of the outer sleeve; the inner diameter of the inner sleeve is larger than the outer diameter of the slag discharge pipe, and the inner diameter of the outer sleeve is larger than the outer diameter of the inner sleeve.
4. The slag discharge pipe structure of a circulating fluidized bed boiler according to claim 1, characterized in that: The secondary sealing device comprises a sealing box and a metal expansion joint, wherein the sealing box is arranged at the lower part of the wind chamber, the metal expansion joint is connected to the lower part of the sealing box, and the slag discharge pipe passes through the sealing box and the metal expansion joint.
5. The slag discharge pipe structure of a circulating fluidized bed boiler according to claim 4, characterized in that: The sealing box comprises a bottom plate and four side wall plates, the four side wall plates are fixedly connected to each other, the lower ends of the four side wall plates are fixedly connected to the bottom plate, the upper ends of the four side wall plates are adapted to the shape of the outer side surface of the bottom wall of the wind chamber and are fixedly connected, and a vertical through hole is provided on the bottom plate, and the slag discharge pipe passes through the vertical through hole and can slide in the vertical through hole; The upper end cover of the metal expansion joint is fixedly connected to the bottom plate of the sealing box, and the lower end cover of the metal expansion joint is fixedly connected to the outer side wall of the slag discharge pipe.
6. The slag discharge pipe structure of a circulating fluidized bed boiler according to claim 5, characterized in that: The metal expansion joint and the sealing box are filled with aluminum silicate refractory fibers.