Fire channeling prevention expansion device applied to slag tapping pipe of circulating fluidized bed boiler
By inserting a protective shell into the lower end of the slag discharge pipe in a circulating fluidized bed boiler and using multi-layer pressure rings and refractory insulation layers, the problems of air leakage and flame movement caused by temperature difference expansion in the slag discharge pipe are solved, thus improving safety and service life.
Patent Information
- Application Number
- CN202520599507.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-01
- Publication Date
- 2026-02-17
- Estimated Expiration
- 2035-04-01
AI Technical Summary
The expansion joints and welds of the slag discharge pipes in circulating fluidized bed boilers may rupture due to temperature differences, causing air leakage and flame flickering, which poses a safety hazard and may lead to a fire.
The slag discharge pipe is inserted into the protective shell at its lower end. Combined with the axial and radial movement of the first, second, third, and thick pressure rings, along with the refractory insulation layer and the protective shell, the problem of slag discharge pipe expansion is solved, forming an airflow barrier to prevent flame spread.
Improve the safety and service life of the slag discharge pipe, prevent flame spread, and enhance safety and reliability.
Smart Images
Figure CN223924792U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of ash discharge systems for circulating fluidized bed boilers, specifically to an anti-flame expansion device applied to the ash discharge pipe of a circulating fluidized bed boiler. Background Technology
[0002] The ash discharge pipe of a circulating fluidized bed boiler is responsible for discharging ash and slag from the furnace. It is an important component of the boiler ash discharge system, affecting the boiler's operating efficiency and the safety of the discharge process.
[0003] To address the issue of high-temperature expansion in slag discharge pipes, existing circulating fluidized bed boilers use two sections for the slag discharge pipe. The upper section connects to the furnace of the boiler, while the lower section connects to the material chamber of the slag cooler. An expansion joint connects the upper and lower sections as a free end. However, due to the high furnace temperature, the inside of the slag discharge pipe is also at a high temperature, while the outside may be affected by cold air. This temperature difference easily causes the expansion joint itself and the weld between the expansion joint and the slag discharge pipe to crack and leak air. This air leakage provides oxygen to combustible materials (such as unburned carbon) in the slag discharge pipe, disrupts the pressure balance, and leads to abnormal airflow. This can cause flames to flicker and spread within the slag discharge pipe, placing it in a dangerous working state and potentially leading to fires or other safety accidents. Utility Model Content
[0004] To address the aforementioned shortcomings of existing technologies, this utility model provides an anti-flame expansion device for slag discharge pipes in circulating fluidized bed boilers. The lower end of the slag discharge pipe is inserted into a protective shell connected to the feed inlet of the slag cooler. The expansion problem of the slag discharge pipe is solved by the axial and radial movement of the first pressure ring, the second pressure ring, the third pressure ring, and the thick pressure ring. At the same time, the refractory insulation layer and the protective shell prevent the lower end of the slag discharge pipe from flaming upwards, thereby improving the safety and service life of the slag discharge pipe.
[0005] To achieve the above objectives, this utility model provides the following technical solution: an anti-flame expansion device for a slag discharge pipe in a circulating fluidized bed boiler, comprising a slag discharge pipe, a cylindrical protective shell, a first pressure ring, a second pressure ring, a third pressure ring, and a thick pressure ring. The slag discharge pipe is vertically arranged and its upper end is connected to the furnace of the circulating fluidized bed boiler. The lower end of the protective shell is vertically arranged and connected to the material chamber of the slag cooler. The inner diameter of the protective shell is larger than the outer diameter of the slag discharge pipe. The lower end of the slag discharge pipe is inserted into the protective shell. A fixing ring is fixedly arranged on the side surface of the slag discharge pipe near its lower end. The inner diameter of the fixing ring is larger than the outer diameter of the slag discharge pipe. The inner diameter of the first pressure ring is smaller than the outer diameter of the fixing ring, and the outer diameter of the first pressure ring is smaller than or equal to the outer diameter of the protective shell. The inner diameter of the shell is such that the first pressure ring is movably pressed onto the fixed ring, and a refractory insulation layer is movably pressed onto both the fixed ring and the first pressure ring. The refractory insulation layer wraps around the outside of the slag discharge pipe. The second pressure ring has the same specifications as the first pressure ring and is movably pressed onto the refractory insulation layer. The third pressure ring has the same specifications as the fixed ring and is movably pressed onto the second pressure ring. The third pressure ring is located inside the protective shell. The inner diameter of the thick pressure ring is larger than the outer diameter of the slag discharge pipe, and the outer diameter of the thick pressure ring is larger than the outer diameter of the protective shell. The thick pressure ring is movably pressed onto the upper end of the protective shell. A gate valve is provided on the slag discharge pipe and at a position corresponding to the upper part of the protective shell. The slag discharge pipe, the protective shell, the first pressure ring, the second pressure ring, the third pressure ring, and the thick pressure ring are all made of rare earth heat-resistant steel.
[0006] Preferably, the slag discharge pipe consists of an upper section and a lower section. The diameter of the upper section is larger than the diameter of the lower section. The upper end of the upper section is connected to the furnace of the circulating fluidized bed boiler. The lower end of the lower section is inserted into the protective shell. The lower end of the upper section and the upper end of the lower section are respectively welded to the slide valve.
[0007] Preferably, the fire-resistant insulation layer is made of zirconium-containing aluminum silicate fiber felt material.
[0008] Preferably, the lower end of the protective shell is designed with a narrowed opening.
[0009] This utility model provides a device for preventing fire spread and expansion in the slag pipe of a circulating fluidized bed boiler, which has the following advantages:
[0010] 1. The lower end of the slag discharge pipe of this utility model is inserted into the protective shell connected to the feed port of the slag cooler. The expansion problem of the slag discharge pipe is solved by the axial and radial movement of the first pressure ring, the second pressure ring, the third pressure ring and the thick pressure ring. At the same time, the refractory insulation layer and the protective shell prevent the lower end of the slag discharge pipe from shooting upwards, thereby improving the safety and service life of the slag discharge pipe.
[0011] 2. The slag discharge pipe of this utility model consists of an upper section and a lower section. The upper end of the lower section is connected to the lower end of the upper section. The outer diameter of the lower section is less than or equal to the inner diameter of the upper section. According to the principle of fluid mechanics, the smaller the diameter, the faster the flow rate, which can make the airflow speed much higher than the flame propagation speed, thereby forming an "airflow barrier" to prevent the flame from spreading to non-target areas. Attached Figure Description
[0012] Figure 1 This is a front view schematic diagram of the present utility model.
[0013] In the diagram: 1. Protective shell; 2. Slag discharge pipe; 3. Slide valve; 4. Narrowing; 5. Fixing ring; 6. First pressure ring; 7. Second pressure ring; 8. Third pressure ring; 9. Thick pressure ring; 10. Refractory insulation layer; 21. Upper section of pipe; 22. Lower section of pipe. Detailed Implementation
[0014] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0015] like Figure 1As shown, an anti-flame expansion device for a slag discharge pipe 2 in a circulating fluidized bed boiler includes a slag discharge pipe 2, a cylindrical protective shell 1, a first pressure ring 6, a second pressure ring 7, a third pressure ring 8, and a thick pressure ring 9. The slag discharge pipe 2 is vertically arranged and its upper end is connected to the furnace of the circulating fluidized bed boiler. The lower end of the protective shell 1 is vertically arranged and connected to the material chamber of the slag cooler. The inner diameter of the protective shell 1 is larger than the outer diameter of the slag discharge pipe 2. The lower end of the slag discharge pipe 2 is inserted into the protective shell 1. A fixing ring 5 is fixedly installed on the two side surfaces near the lower end. The inner diameter of the fixing ring 5 is larger than the outer diameter of the slag discharge pipe 2. The inner diameter of the first pressure ring 6 is smaller than the outer diameter of the fixing ring 5, and the outer diameter of the first pressure ring 6 is smaller than or equal to the inner diameter of the protective shell 1. The first pressure ring 6 is movably pressed onto the fixing ring 5. A refractory insulation layer 10 is movably pressed onto the fixing ring 5 and the first pressure ring 6. The refractory insulation layer 10 wraps around the outside of the slag discharge pipe 2. The second pressure ring 7 has the same specifications as the first pressure ring 6 and is movable. The third pressure ring 8 is pressed onto the refractory insulation layer 10. It has the same specifications as the fixed ring 5 and is movably pressed onto the second pressure ring 7. The third pressure ring 8 is located inside the protective shell 1. The inner diameter of the thick pressure ring 9 is larger than the outer diameter of the slag discharge pipe 2, and the outer diameter of the thick pressure ring 9 is larger than the outer diameter of the protective shell 1. The thick pressure ring 9 is movably pressed onto the upper end of the protective shell 1. A slide valve 3 is installed on the slag discharge pipe 2, corresponding to the position above the protective shell 1. The components include the slag discharge pipe 2, the protective shell 1, the first pressure ring 6, and the second pressure ring 7. Both the third pressure ring 8 and the thick pressure ring 9 are made of rare earth heat-resistant steel. The slag discharge pipe 2 consists of an upper section 21 and a lower section 22. The diameter of the upper section 21 is larger than the diameter of the lower end. The upper end of the upper section 21 is connected to the furnace of the circulating fluidized bed boiler. The lower end of the lower section 22 is inserted into the protective shell 1. The lower end of the upper section 21 and the upper end of the lower section 22 are respectively welded to the slide valve 3. The refractory insulation layer 10 is made of zirconium-containing aluminum silicate fiber felt. The lower end of the protective shell 1 is designed with a constriction 4.
[0016] Its detailed connection methods are well-known technologies in this field. The following mainly introduces the working principle and process, as follows:
[0017] According to the instruction manual Figure 1It is known that the slag lowering pipe 2, protective shell 1, first pressure ring 6, second pressure ring 7, third pressure ring 8, and thick pressure ring 9 in this utility model are all made of rare earth heat-resistant steel with excellent high-temperature resistance. This material can maintain stable physical and chemical properties at high temperatures, is not easily deformed or damaged, and extends its service life. During operation, slag material enters the material chamber of the slag cooler from the furnace of the circulating fluidized bed boiler through the slag lowering pipe 2 and the protective shell 1, and can be controlled to open and close by the slide valve 3. The slag lowering pipe 2 may undergo axial and radial expansion due to high temperature. When the slag discharge pipe 2 expands axially, since the upper section of the slag discharge pipe 2 is fixed and the lower end is an insertion type, the lower end of the slag discharge pipe 2 is a free end. The slag discharge pipe 2 will expand downward, causing the fixed ring 5 to move downward. Since the inner diameters of the third pressure ring 8 and the thick pressure ring 9 are both larger than the outer diameter of the slag discharge pipe 2, they can move relative to each other, thus not affecting the axial expansion of the slag discharge pipe 2. When the slag discharge pipe 2 expands radially, since the first pressure ring 6 and the fixed ring 5, the second pressure ring 7 and the refractory insulation layer 10, the third pressure ring 8 and the second pressure ring 7, and the thick pressure ring 9 and the upper end of the protective shell 1 are all movable, they can move axially and radially, thus not affecting the radial expansion of the slag discharge pipe 2. At the same time, since the inner diameter of the first pressure ring 6 is smaller than the outer diameter of the fixed ring 5, and the outer diameter of the first pressure ring 6 is smaller than the outer diameter of the fixed ring 5, the radial expansion of the slag discharge pipe 2 will not be affected. The inner diameter of the protective shell 1 is equal to or greater than that of the first pressure ring 6. Therefore, the first pressure ring 6 and the fixed ring 5 can not only move relative to each other, but also seal the annular cavity between the slag discharge pipe 2 and the protective shell 1, preventing the lower end of the slag discharge pipe 2 from escaping through the gap between the slag discharge pipe 2 and the protective shell 1. The second pressure ring 7 and the third pressure ring 8 have the same function. The refractory insulation layer 10 not only insulates the slag discharge pipe 2 to prevent cold air from contacting the high temperature of the slag discharge pipe 2, but also seals the annular cavity between the slag discharge pipe 2 and the protective shell 1. In addition, the thick pressure ring 9 seals the annular cavity between the slag discharge pipe 2 and the protective shell 1 as a whole. Under the above four-fold sealing protection, the problem of escaping through the slag discharge pipe 2 can be solved, and the safety and service life of the slag discharge pipe 2 can be improved.
[0018] The slag discharge pipe 2 consists of an upper section 21 and a lower section 22. The diameter of the upper section 21 is larger than that of the lower section. The upper end of the upper section 21 is connected to the furnace of the circulating fluidized bed boiler, and the lower end of the lower section 22 is inserted into the protective shell 1. The lower ends of the upper section 21 and the upper ends of the lower section 22 are respectively welded to the gate valve 3. During operation, as the slag is transported from the upper section 21 to the lower section 22, a narrowing channel design is created. According to fluid mechanics principles, a smaller diameter results in a faster flow velocity, allowing the airflow speed to be much higher than the flame propagation speed, thus forming an "airflow barrier" to prevent the flame from spreading to non-target areas. Furthermore, the lower end of the protective shell 1 can also be designed with a constriction 4, based on the same principle as the aforementioned diameter reduction design.
[0019] The refractory insulation layer 10 is made of zirconium-containing aluminosilicate fiber felt. Traditional refractory insulation materials include aluminosilicate boards and refractory fibers, but this invention uses zirconium-containing aluminosilicate fiber felt, which has a high melting point and low thermal conductivity. Its long-term operating temperature can reach 1600 degrees Celsius, and it exhibits superior seismic resistance and chemical stability. This material effectively reduces the temperature difference between the inside and outside of the pipe wall and the movement of flames within the slag discharge pipe 2, protecting the slag discharge pipe 2 from the direct impact of high-temperature flames.
[0020] In addition, the fixing ring 5 can be fixed to the slag discharge pipe 2 by welding, leaving a certain space for the lower end of the slag discharge pipe 2 to be damaged at a position 50mm away from the lower end of the slag discharge pipe 2.
[0021] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A device for preventing fire spread and expansion in the slag discharge pipe (2) of a circulating fluidized bed boiler, characterized in that, The system includes a slag discharge pipe (2), a cylindrical protective shell (1), a first pressure ring (6), a second pressure ring (7), a third pressure ring (8), and a thick pressure ring (9). The slag discharge pipe (2) is vertically arranged and its upper end is connected to the furnace of the circulating fluidized bed boiler. The lower end of the protective shell (1) is vertically arranged and connected to the material chamber of the slag cooler. The inner diameter of the protective shell (1) is larger than the outer diameter of the slag discharge pipe (2). The lower end of the slag discharge pipe (2) is inserted into the interior of the protective shell (1). A fixing ring (5) is fixedly arranged on the side surface of the slag discharge pipe (2) near its lower end. The inner diameter of the fixing ring (5) is larger than the outer diameter of the slag discharge pipe (2). The inner diameter of the first pressure ring (6) is smaller than the outer diameter of the fixing ring (5), and the outer diameter of the first pressure ring (6) is smaller than or equal to the inner diameter of the protective shell (1). The first pressure ring (6) is movably pressed onto the fixing ring (5). The fixing ring (5) and the first pressure ring... (6) A refractory insulation layer (10) is provided on the upper part of the slag pipe (2). The refractory insulation layer (10) is wrapped around the outside of the slag pipe (2). The second pressure ring (7) is the same as the first pressure ring (6) and is movably pressed on the refractory insulation layer (10). The third pressure ring (8) is the same as the fixed ring (5) and is movably pressed on the second pressure ring (7). The third pressure ring (8) is located inside the protective shell (1). The inner diameter of the thick pressure ring (9) is larger than the outer diameter of the slag pipe (2) and the outer diameter of the thick pressure ring (9) is larger than the outer diameter of the protective shell (1). The thick pressure ring (9) is movably pressed on the upper end of the protective shell (1). A slide valve (3) is provided on the slag pipe (2) and at the position corresponding to the upper part of the protective shell (1). The slag pipe (2), the protective shell (1), the first pressure ring (6), the second pressure ring (7), the third pressure ring (8) and the thick pressure ring (9) are all made of rare earth heat-resistant steel.
2. The anti-flame expansion device for the slag pipe (2) of a circulating fluidized bed boiler according to claim 1, characterized in that, The slag discharge pipe (2) consists of an upper section (21) and a lower section (22). The diameter of the upper section (21) is larger than the diameter of the lower end. The upper end of the upper section (21) is connected to the furnace of the circulating fluidized bed boiler. The lower end of the lower section (22) is inserted into the protective shell (1). The lower end of the upper section (21) and the upper end of the lower section (22) are respectively welded to the slide valve (3).
3. The anti-flame expansion device for the slag discharge pipe (2) of a circulating fluidized bed boiler according to claim 1, characterized in that, The fire-resistant insulation layer (10) is made of zirconium-containing aluminum silicate fiber felt material.
4. The anti-flame expansion device for the slag discharge pipe (2) of a circulating fluidized bed boiler according to claim 1, characterized in that, The lower end of the protective shell (1) is designed with a narrow opening (4).