Heat preservation structure of circulating fluidized bed boiler
By adopting multi-layer insulation materials and structures in key parts of the circulating fluidized bed boiler, the overtemperature problem of the boiler is solved, the heat dissipation loss is reduced, and the operating environment is provided, and the thermal efficiency and economicality of the boiler are improved.
Patent Information
- Application Number
- CN202323217503.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2023-11-28
- Publication Date
- 2025-02-21
- Estimated Expiration
- 2033-11-28
AI Technical Summary
There are overtemperature problems in the furnace top, front wall, high, high re-exit container, rear shaft low temperature superheater, low temperature reheater and low temperature reheater inlet and outlet container, resulting in increased heat dissipation loss and Poor operating environment.
A circulating fluidized bed boiler insulation structure is designed, through the furnace top and top, high, high re-export container, front wall, high, high re-introduction container and rear shaft low temperature superheater, The inlet and outlet of the low-temperature reheater adopts multi-layer insulation materials and structures, including aluminum silicate refractory fiber blanket, aluminum silicate loose cotton, refractory plastic and high-temperature glass wool, respectively, used to separate the inner pipe space of the container. , enhance the thickness and sealing of the insulation layer, and prevent air convection and heat loss.
Through reasonable insulation design, the local overtemperature problem of boiler is effectively solved, the heat dissipation loss is reduced, the operating environment is provided, and the thermal efficiency and economicality of the boiler are improved.
Smart Images
Figure CN222514009U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of fluidized bed boiler insulation, in particular to a circulating fluidized bed boiler insulation structure. Background Art
[0002] Circulating fluidized bed boiler combustion technology is a high-efficiency, low-pollution clean coal-burning technology developed in the past 20 years. It has outstanding advantages such as wide fuel adaptability, high combustion efficiency, and low nitrogen oxide emissions. It is suitable for my country's efficient use of coal and energy conservation and emission reduction. It still has broad development potential in the future. Therefore, the clean and efficient use of fuel has become the focus of attention of operating units. How to improve the thermal efficiency of boilers, reduce fuel consumption, and improve the economy of boilers is very important; boilers are an important part of the unit. Reasonable insulation structure and good construction technology are the basic conditions to ensure the normal operation of the unit. The basic function of boiler insulation is to insulate the boiler and reduce its heat dissipation loss. It is also to create The basic guarantee for good operating conditions, the insulation effect of the boiler directly affects the coal consumption index. Controlling boiler overtemperature is a key measure to reduce coal consumption. After years of continuous improvement and research on insulation design and construction by scientific researchers, there are no overtemperature points in a large area, but there are still some inadequate considerations in the subtle parts. According to the operation of several circulating fluidized bed boilers above 300MW, it was found that the insulation overtemperature parts are mainly ① the top of the furnace and the top middle pass, high pass, high re-export header, ② the front wall middle pass, high pass, high re-inlet header, ③ the rear shaft low-temperature superheater, and the low-temperature reheater inlet and outlet headers. Therefore, it is necessary to optimize the insulation structure of circulating fluidized bed boilers above 300MW based on these problems. Summary of the invention
[0003] In order to solve the above problems, the utility model provides a circulating fluidized bed boiler insulation structure.
[0004] The technical solution adopted by this utility model:
[0005] A circulating fluidized bed boiler insulation structure includes the insulation structure of the furnace top and the top middle-pass, high-pass and high re-export headers, the insulation structure of the front wall middle-pass, high-pass and high re-inlet headers and the insulation structure of the rear shaft low-temperature superheater and low-temperature reheater inlet and outlet headers. The insulation structure of the furnace top and the top middle-pass, high-pass and high re-export headers is to separately insulate the high re-export header and the high-pass outlet header.
[0006] The insulation structure of the high re-export header and the high super-export header is that the internal pipe row space of the high re-export header and the high super-export header is divided into multiple small spaces by aluminum silicate loose wool partitions, the insulation structure of the furnace top is a 320mm aluminum silicate refractory fiber blanket, the outer protective layer is a color steel corrugated plate, the sealing box where the header pipe row passes through the ceiling is filled with refractory plastic and aluminum silicate loose wool, the inside of the expansion joint at the top of the sealing box is filled with aluminum silicate loose wool, and the outside of the metal expansion joint and the sealing box is a 150mm thick aluminum silicate refractory fiber blanket.
[0007] The insulation structure of the middle pass, high pass and high re-inlet headers on the front wall of the furnace is a 270mm thick aluminum silicate refractory fiber blanket, and the space between the header pipe rows is filled with aluminum silicate loose wool.
[0008] The insulation structure of the low-pass and low-re-inlet and outlet headers of the rear shaft includes a 130mm thick high-temperature glass wool and a 170mm thick aluminum silicate refractory fiber blanket as the insulation structure of the header top, and an aluminum silicate loose wool partition is set in the middle space of the header pipe row to separate it into multiple small spaces.
[0009] The thickness of the fire-resistant plastic material is 80 mm.
[0010] The aluminum silicate loose wool partitions are arranged every 3 meters in the header pipe row space.
[0011] Beneficial effects of the utility model: the utility model reasonably designs the often over-temperature parts of the circulating fluidized bed boiler, and separately insulates the high re-outlet header and the high over-outlet header, thereby solving the problem of local over-temperature of the boiler, reducing the heat dissipation loss of the boiler and providing a good operating environment. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 This is a schematic diagram of the furnace top and header structure of the utility model.
[0013] Figure 2 This is a schematic diagram of the furnace front wall header structure of the utility model.
[0014] Figure 3 It is a schematic diagram of the rear shaft header structure of the utility model.
[0015] Among them: 1-color steel corrugated board; 2-320mm aluminum silicate refractory fiber blanket; 3-aluminum silicate loose wool partition; 4-130mm thick high-temperature glass wool; 5-150mm thick aluminum silicate refractory fiber blanket; 6-aluminum silicate loose wool; 7-refractory plastic material; 8-170mm thick aluminum silicate refractory fiber blanket; 9-270mm thick aluminum silicate refractory fiber blanket. DETAILED DESCRIPTION
[0016] The reasons for the overheating problem at the top of the furnace are: Reason 1: Due to the floating of hot air, the top of the furnace bears the highest temperature. This factor was not considered when designing the insulation layer, and the lightweight insulation castable has a high thermal conductivity. It is easy to produce tiny cracks when heated and expanded. The heat expands outward with the cracks, causing the furnace top to overheat. Reason 2: The sealing box where the header pipes pass through the ceiling is made of refractory plastic and loose cotton. The expansion joint at the top of the sealing box is filled with loose cotton and there is no insulation on the outside. The sealing box and expansion joint are directly connected to the header for heat conduction, and no insulation is designed on the outside, resulting in heat dissipation and overheating. Reason 3: The high-temperature reheater and high-temperature superheater outlet headers are designed to be covered with insulation as a whole, forming an enclosed space inside the two headers, and their own temperatures are different, forming air convection and causing overheating. Reason 4: The insulation layer of the header is designed as a composite structure of aluminum silicate + high-temperature glass wool. Since the safe operating temperature of high-temperature glass wool is 300℃, it loses its insulation effect when it encounters high temperature; the expansion of the boiler during operation forms a tiny gap in the aluminum silicate, and the high temperature escapes from the gap, causing the glass wool to fail and cause overheating; The reason for the overheating of the header in the middle, high, and high re-inlet of the front wall of the furnace: Reason 1: There is a closed space in the middle of the header pipe row, which forms air convection and causes overheating. Reason 2: The insulation layer of the header is designed as a composite structure of aluminum silicate refractory fiber blanket + high-temperature glass wool. Since the safe operating temperature of glass wool is 300℃, it loses its insulation effect when it encounters high temperature and causes overheating; Reason 3: The sealing box at the front wall of the header is directly connected to the water-cooled wall for heat conduction, and the external high-temperature glass wool fails when it encounters high temperature, causing overheating. The reason for the overheating of the header in the low-pass, low-re-inlet and outlet of the rear shaft: Reason 1: There is a closed space in the middle of the header pipe row, which forms air convection and causes overheating. Reason 2: Due to the rising of hot air, the top of the header bears the highest temperature. This factor was not taken into account when designing the insulation layer, resulting in overheating.
[0017] A circulating fluidized bed boiler insulation structure comprises an insulation structure of a furnace top and a middle-pass, high-pass and high-re-export header at the top, an insulation structure of a middle-pass, high-pass and high-re-export header at the front wall and an insulation structure of an inlet and outlet header of a low-temperature superheater and a low-temperature reheater at a rear shaft. The insulation structure of the furnace top and the middle-pass, high-pass and high-re-export header at the top is to separately insulate a high re-export header and a high-pass outlet header, the interiors of the two headers being a relatively large enclosed space, and separating the two headers can reduce the space and reduce air convection.
[0018] The insulation structure of the high re-export header and the high super-export header is that the internal pipe row space of the high re-export header and the high super-export header is divided into multiple small spaces every 3m by aluminum silicate loose wool partitions 3, which can be used to prevent air convection. The insulation structure of the furnace top is a 320mm aluminum silicate refractory fiber blanket 2, and the outer protective layer is a color steel corrugated plate 1. The sealing box where the header pipe row passes through the ceiling is filled with refractory plastic 7 and aluminum silicate loose wool 6. The thickness of the refractory plastic 7 is 80mm, and the upper expansion joint of the sealing box is filled with aluminum silicate loose wool 6. The outside of the metal expansion joint and the sealing box is a 150mm thick aluminum silicate refractory fiber blanket 5. The sealing box and the expansion joint are directly connected to the header for heat conduction, and the aluminum silicate refractory fiber blanket 5 is designed on the outside, so the heat cannot be dissipated and will not form over-temperature.
[0019] The insulation structure of the middle, high and high re-inlet headers on the front wall of the furnace is a 270mm thick aluminum silicate refractory fiber blanket 9, and the space between the header pipe rows is filled with aluminum silicate loose wool 6 to prevent the high-temperature glass wool from losing its insulation effect when encountering high temperatures and causing overheating.
[0020] The insulation structure of the low-pass and low-re-inlet and outlet headers of the rear shaft, wherein the top insulation structure of the header is 130 mm thick high-temperature glass wool 4 and 170 mm thick aluminum silicate refractory fiber blanket 8. The hot air floats to the top of the header to withstand the highest temperature. Aluminum silicate loose wool partitions 3 are set in the middle space of the header pipe row to divide it into multiple small spaces every 3 meters to prevent air convection, thereby avoiding the formation of air convection in the entire enclosed space in the middle of the header pipe row.
[0021] Temperature measurement is carried out when the unit is running at full load: after insulation construction of the furnace top and the top middle-pass, high-pass and high-re-export headers, the average ceiling temperature of #1 boiler is 44.6°C, and the average header temperature is 48.7°C; the average ceiling temperature of #2 boiler is 43.2°C, and the average header temperature is 46.5°C; after construction of the insulation structure of the middle-pass, high-pass and high-re-inlet headers on the front wall of the furnace, the average temperature of #1 boiler is 44.8°C; the average temperature of #2 boiler is 43.8°C, and after construction of the insulation structure of the rear shaft header, the average temperature of #1 boiler is 45.5°C; the temperature of #2 boiler is 49.4°C.
[0022] The above is a detailed description of the embodiments of the utility model, but the contents are only preferred embodiments of the utility model and cannot be considered to limit the scope of implementation of the utility model. All equivalent changes and improvements made within the scope of application of the utility model should still fall within the scope of the patent coverage of the utility model.
Claims
1. A circulating fluidized bed boiler insulation structure, characterized in that: It includes the insulation structure of the furnace top and the middle, high and high re-export headers at the top, the insulation structure of the middle, high and high re-export headers at the front wall, and the insulation structure of the low-temperature superheater and low-temperature reheater inlet and outlet headers at the rear shaft. The insulation structure of the furnace top and the middle, high and high re-export headers at the top is to insulate the high re-export header and the high-temperature outlet header separately; The insulation structure of the high re-export header and the high super-export header is that the internal pipe row space of the high re-export header and the high super-export header is divided into multiple small spaces by aluminum silicate loose wool partitions, the insulation structure of the furnace top is a 320mm thick aluminum silicate refractory fiber blanket (2), the outer protective layer is a color steel corrugated plate (1), the sealing box where the header pipe row passes through the ceiling is filled with refractory plastic (7) and aluminum silicate loose wool (6), the expansion joint at the top of the sealing box is filled with aluminum silicate loose wool (6), and the outside of the metal expansion joint and the sealing box is a 150mm thick aluminum silicate refractory fiber blanket (5).
2. The circulating fluidized bed boiler insulation structure according to claim 1, characterized in that: The front wall middle pass, high pass and high re-inlet header insulation structure is a 270mm thick aluminum silicate refractory fiber blanket (9), and the space between the header pipe rows is filled with aluminum silicate loose wool (6).
3. The circulating fluidized bed boiler insulation structure according to claim 1, characterized in that: The insulation structure of the low-pass and low-re-inlet and outlet headers of the rear shaft includes a 130mm thick high-temperature glass wool (4) and a 170mm thick aluminum silicate refractory fiber blanket (8), and an aluminum silicate loose wool partition (3) is arranged in the middle space of the header pipe row to separate it into multiple small spaces.
4. The circulating fluidized bed boiler insulation structure according to claim 1, characterized in that: The thickness of the fire-resistant plastic material (7) is 80 mm.
5. The circulating fluidized bed boiler insulation structure according to claim 1 or 3, characterized in that: The aluminum silicate loose wool partition (3) is arranged every 3 m in the header pipe row space.