Air distribution system of circulating fluidized bed boiler

Abstract

The utility model relates to the technical field of boilers, in particular to a circulating fluidized bed boiler air distribution system which comprises a boiler, an air distribution plate, a fixing frame and an impeller, the boiler is provided with a containing cavity, the containing cavity is divided into a combustion chamber and an air chamber through the air distribution plate, the combustion chamber is arranged above the air distribution plate, and an air inlet is formed in the side wall of the boiler and communicates with the air chamber; the fixing frame is fixedly connected to the inner wall of the air chamber, the height of the fixing frame is larger than that of the air inlet, the impellers are coaxially and fixedly connected with a driving shaft, the driving shaft is rotatably connected to the fixing frame around the axis of the driving shaft, the rotating axis of the driving shaft is vertical, and the multiple impellers are evenly arranged at intervals in the width direction of the air chamber. The adjacent driving shafts are connected through a synchronizing piece. Air enters the air chamber from the air inlet to push the impellers to rotate, the impellers drive the adjacent impellers to rotate through the synchronizing pieces while rotating, the multiple impellers are the same in rotating speed, air is supplemented through the impellers in the area with the small air volume, air distribution in the air chamber is promoted to be uniform, and air distribution uniformity is improved.

Description

Technical Field

[0001] The present application relates to the field of boiler technology, and in particular to an air distribution system for a circulating fluidized bed boiler. Background Art

[0002] The circulating fluidized bed boiler is a new type of high-efficiency and energy-saving coal-fired boiler. It uses circulating fluidized bed combustion technology to allow coal to burn at low temperatures, greatly reducing the emission of nitrogen oxides and particulate matter. This boiler has the characteristics of strong fuel adaptability, uniform temperature distribution, and a wide range of heat load adjustment. Therefore, it can be widely used in power generation, thermal power, chemical industry and other fields.

[0003] The working principle of a circulating fluidized bed boiler is that the raw fuel passes through a pretreatment system to ensure the uniformity and combustibility of the fuel. The treated fuel is fed into the boiler combustion chamber through a screw coal feeder or elevator. Inside the combustion chamber, the fuel and air are fully mixed, and a combustion reaction occurs under high temperature and high pressure. At the same time, sufficient fluidizing medium, generally sand or granular material, is injected into the circulating fluidized bed to maintain the stability and fluidization of the bed. The heat energy generated by the fuel combustion is transferred to the fluidizing medium in the circulating fluidized bed and transferred to the boiler heat exchange surface through the heat transfer tube bundle, thereby heating the water and converting it into steam for power generation or heating.

[0004] In order to further improve the efficiency of the boiler unit of the circulating fluidized bed boiler and reduce the pressure of pollutant emissions, the circulating fluidized bed boiler is developing in the direction of supercritical, high parameters and large capacity. Among them, the design of the air distribution device is one of the key technologies of the supercritical circulating fluidized bed boiler. Due to the limitation of the system layout, large boilers adopt a single-side air intake layout. Since the size of the boiler along the depth direction is larger after the large-scale, the single-side air intake will cause uneven distribution of air volume along the depth direction of the furnace.

[0005] Uneven air volume distribution directly leads to uneven distribution of bed material particle size, partitioning of coarse and fine particles in bed material, and accumulation of coarse particles will lead to poor local fluidization of bed material, and even hidden dangers of coking, and may also lead to incomplete combustion and high carbon content in bottom ash, which directly affects boiler performance indicators. At the same time, due to the uneven distribution of air volume along the depth direction, horizontal swirl will also appear in the furnace, and high-concentration dust-laden airflow will form horizontal scouring on the water-cooled wall, resulting in serious wear of the water-cooled wall, reducing its service life and continuous operation of the unit. Utility Model Content

[0006] In order to improve the uniformity of air volume distribution, the present application provides an air distribution system for a circulating fluidized bed boiler.

[0007] The circulating fluidized bed boiler air distribution system provided in this application adopts the following technical solution:

[0008] A circulating fluidized bed boiler air distribution system comprises a boiler, an air distribution plate, a fixing frame and an impeller, the boiler is provided with a accommodating chamber, the air distribution plate is fixedly connected to the inner wall of the accommodating chamber, the air distribution plate is horizontally arranged, a plurality of wind hoods are connected to the air distribution plate, the air distribution plate divides the accommodating chamber into a combustion chamber and a wind chamber, the combustion chamber is arranged above the air distribution plate, the side wall of the boiler is provided with an air inlet, the air inlet is connected to the wind chamber, the fixing frame is fixedly connected to the inner wall of the wind chamber, the height of the fixing frame is greater than the height of the air inlet, the impeller is coaxially fixedly connected to a driving shaft, the driving shaft is rotatably connected to the fixing frame around its own axis, the rotation axis of the driving shaft is vertical, a plurality of impellers are provided, the plurality of impellers are evenly spaced along the width direction of the wind chamber, and adjacent driving shafts are connected by synchronizers.

[0009] By adopting the above technical solution, wind enters the air chamber from the air inlet, and the wind drives the impeller to rotate. While the impeller rotates, the adjacent impellers are driven to rotate through the synchronous parts. The speed of multiple impellers is the same. The impeller can supplement the air volume in the area with small air volume, thereby promoting uniform air volume distribution in the air chamber and improving the uniformity of air volume distribution.

[0010] Preferably, the synchronous component includes a synchronous wheel and a synchronous belt, the synchronous wheel is coaxially fixedly connected to the drive shaft, and the synchronous belt is sleeved on the outer circumference of two adjacent synchronous wheels.

[0011] By adopting the above technical solution, the impeller is driven to rotate synchronously by the synchronous wheel and the synchronous belt, which has a simple structure, is easy to operate and is not easy to be damaged.

[0012] Preferably, the plurality of impellers are evenly spaced along the length direction of the wind chamber.

[0013] By adopting the above technical solution, the impellers are evenly spaced along the length and width directions of the wind chamber, which promotes uniform distribution of components in various areas in the wind chamber and improves the uniformity of air volume distribution.

[0014] Preferably, the height of the bottom wall of the air chamber increases as it moves away from the air inlet.

[0015] By adopting the above technical solution, the unilateral air intake makes the air volume gradually increase along the air intake direction, changes the height of the bottom wall of the air chamber, creates a certain obstruction to the air intake, promotes the upward movement of the wind, and improves the uniformity of air volume distribution.

[0016] Preferably, the outer wall of the boiler is provided with a feed inlet, and the feed inlet is connected to the combustion chamber. There are multiple feed inlets, and the multiple feed inlets are evenly divided into two groups. The two groups of feed inlets are respectively close to the two ends of the air distribution plate in the width direction, and each group of feed inlets is evenly spaced along the length direction of the air distribution plate.

[0017] By adopting the above technical solution, the feed inlets evenly distributed on both sides of the boiler make the fuel feed uniform, promote uniform mixing of fuel and bed material, improve combustion efficiency and combustion quality, and reduce energy loss.

[0018] Preferably, the opening of the feed port in the combustion chamber faces the air distribution plate.

[0019] By adopting the above technical solution, the feeding is smooth, and the fuel is convenient to fall into the area above the air distribution plate.

[0020] Preferably, along the width direction of the air distribution plate, the air distribution plate is sequentially provided with a first air distribution area, a second air distribution area and a third air distribution area, the hood density of the first air distribution area is greater than the hood density of the second air distribution area, and the hood density of the third air distribution area is greater than the hood density of the second air distribution area.

[0021] By adopting the above technical solution, the second air distribution area needs to bear the pressure formed by the bed material directly above and provide the kinetic energy of the upward flow. In addition to bearing the pressure formed by the bed material directly above and providing the upward kinetic energy, the first and third air distribution areas also need to bear the pressure formed by the descending fuel from the edge. The hood density of the first air distribution area is greater than that of the second air distribution area, and the hood density of the third air distribution area is greater than that of the second air distribution area, which promotes the simultaneous fluidization of the fuel above the air distribution plate and improves the burnout degree of the fuel.

[0022] Preferably, a plurality of the hoods are distributed in an array, and are evenly spaced along the length direction of the air distribution plate. Along the width direction of the air distribution plate, the spacing between adjacent hoods in the second air distribution area is smaller than the spacing between adjacent hoods in the first air distribution area, and the spacing between adjacent hoods in the second air distribution area is smaller than the spacing between adjacent hoods in the third air distribution area.

[0023] By adopting the above technical solution, since the feed ports are evenly spaced along the length direction of the air distribution plate, there is no need to adjust the wind hood spacing along the length direction of the air distribution plate. By adjusting the wind hood spacing in the width direction of the air distribution plate, the air volume provided by the first air distribution area and the third air distribution area can overcome the pressure generated by the descending fuel, thereby causing the fuel above the air distribution plate to fluidize simultaneously.

[0024] Preferably, the spacing between adjacent hoods in the first wind distribution area is equal to the spacing between adjacent hoods in the third wind distribution area.

[0025] By adopting the above technical solution, the probability of wind moving laterally in the combustion chamber is reduced.

[0026] In summary, the present application includes at least one of the following beneficial technical effects:

[0027] 1. The wind enters the air chamber from the air inlet, and the wind drives the impeller to rotate. While the impeller rotates, the adjacent impellers are driven to rotate through the synchronous parts. Multiple impellers have the same speed. The impeller can supplement the air volume in the area with small air volume, promote the uniform distribution of air volume in the air chamber, and improve the uniformity of air volume distribution;

[0028] 2. The single-sided air intake makes the air volume gradually increase along the air intake direction, changes the height of the bottom wall of the air chamber, creates a certain obstruction to the air intake, promotes the upward movement of the wind, and improves the uniformity of air volume distribution;

[0029] 3. The second air distribution area needs to bear the pressure formed by the bed material directly above and provide the kinetic energy of the upward flow. In addition to bearing the pressure formed by the bed material directly above and providing the upward kinetic energy, the first and third air distribution areas also need to bear the pressure formed by the descending fuel from the edge. The hood density of the first air distribution area is greater than that of the second air distribution area, and the hood density of the third air distribution area is greater than that of the second air distribution area, which promotes the simultaneous fluidization of the fuel above the air distribution plate and improves the burnout degree of the fuel. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a cross-sectional view of the circulating fluidized bed boiler air distribution system.

[0031] Explanation of the reference numerals: 1. boiler; 11. accommodating chamber; 111. combustion chamber; 112. wind chamber; 12. air inlet; 13. feed inlet; 2. air distribution plate; 21. first air distribution area; 22. second air distribution area; 23. third air distribution area; 24. hood; 3. auxiliary component; 31. fixing frame; 311. mounting opening; 312. air outlet; 32. impeller; 321. drive shaft; 33. synchronous member; 331. synchronous wheel; 332. synchronous belt. DETAILED DESCRIPTION

[0032] The following is combined with Figure 1 This application is described in further detail.

[0033] The present application embodiment discloses a circulating fluidized bed boiler air distribution system. Figure 1 A circulating fluidized bed boiler air distribution system includes a boiler 1, an air distribution plate 2 and an auxiliary component 3.

[0034] The boiler 1 is provided with a accommodating cavity 11, and an air distribution plate 2 is fixedly connected to the inner wall of the accommodating cavity 11. The air distribution plate 2 is horizontally arranged, and the air distribution plate 2 divides the accommodating cavity 11 into a combustion chamber 111 and a wind chamber 112. The combustion chamber 111 is arranged above the air distribution plate 2, and the wind chamber 112 is arranged below the air distribution plate 2. The length direction of the air distribution plate 2 is parallel to the length direction of the boiler 1, and the width direction of the air distribution plate 2 is parallel to the width direction of the boiler 1.

[0035] Reference Figure 1The side wall of the boiler 1 is provided with an air inlet 12, which is connected to the wind chamber 112. The length direction of the air inlet 12 is parallel to the length direction of the air distribution plate 2, and the width direction of the air inlet 12 is parallel to the height direction of the boiler 1. The height of the bottom wall of the wind chamber 112 increases as it moves away from the air inlet 12.

[0036] A feed port 13 is provided on the side wall of the boiler 1, and the feed port 13 is connected to the combustion chamber 111. There are multiple feed ports 13, and the multiple feed ports 13 are evenly divided into two groups. The two groups of feed ports 13 are respectively close to the two ends in the width direction of the air distribution plate 2. Each group of feed ports 13 is evenly spaced along the length direction of the air distribution plate 2, and the openings of the feed ports 13 in the combustion chamber 111 face the air distribution plate 2.

[0037] Reference Figure 1 The auxiliary component 3 includes a fixing frame 31, an impeller 32 and a synchronization member 33. The fixing frame 31 is fixedly connected to the inner wall of the air chamber 112, the height of the fixing frame 31 is greater than the height of the air inlet 12, the length direction of the fixing frame 31 is parallel to the length direction of the air distribution plate 2, and the width direction of the fixing frame 31 is parallel to the width direction of the air distribution plate 2.

[0038] The impeller 32 is coaxially fixedly connected with the driving shaft 321, the fixing frame 31 is provided with a mounting opening 311, the mounting opening 311 vertically penetrates the fixing frame 31, the driving shaft 321 rotates around its own axis and is connected to the inner wall of the mounting opening 311, the impeller 32 is arranged above the fixing frame 31, and the impeller 32 is used to push the wind below the fixing frame 31 to the air distribution plate 2. There are multiple mounting openings 311, and the multiple mounting openings 311 are arranged in an array on the fixing frame 31, and the multiple mounting openings 311 are evenly spaced along the length direction and width direction of the fixing frame 31, and the spacing between adjacent mounting openings 311 along the length direction of the fixing frame 31 is equal to the spacing between adjacent mounting openings 311 along the width direction of the fixing frame 31. The fixing frame 31 is provided with an air outlet 312, and the air outlet 312 vertically penetrates the fixing frame 31.

[0039] Reference Figure 1 Adjacent drive shafts 321 are connected by synchronizers 33, which are disposed below the fixed frame 31. The synchronizers 33 include synchronizer wheels 331 and synchronizer belts 332. The synchronizer wheels 331 are coaxially fixedly connected to the outer wall of the drive shafts 321, and the synchronizer belts 332 are sleeved on the outer peripheries of the adjacent synchronizer wheels 331.

[0040] Along the width direction of the air distribution plate 2, the air distribution plate 2 is provided with a first air distribution area 21, a second air distribution area 22 and a third air distribution area 23 in sequence. A plurality of hoods 24 are connected to the air distribution plate 2. The density of the hoods 24 in the first air distribution area 21 is greater than that in the second air distribution area 22, and the density of the hoods 24 in the third air distribution area 23 is greater than that in the second air distribution area 22. The plurality of hoods 24 are arranged in an array. Along the length direction of the air distribution plate 2, the plurality of hoods 24 are evenly spaced. Along the width direction of the air distribution plate 2, the spacing between adjacent hoods 24 in the second air distribution area 22 is smaller than that in the first air distribution area 21, and the spacing between adjacent hoods 24 in the second air distribution area 22 is smaller than that in the third air distribution area 23. The spacing between adjacent hoods 24 in the first air distribution area 21 is equal to the spacing between adjacent hoods 24 in the third air distribution area 23.

[0041] The implementation principle of the circulating fluidized bed boiler air distribution system in the embodiment of the present application is as follows: the wind enters the wind chamber 112 from the air inlet 12. Due to the inclination of the bottom wall of the wind chamber 112 and the action of the auxiliary component 3, the air volume is evenly distributed in the wind chamber 112. Since the wind hood 24 is unevenly distributed on the air distribution plate 2, the air volume in different areas is different, which promotes the simultaneous fluidization of the fuel in the combustion chamber 111.

[0042] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A circulating fluidized bed boiler air distribution system, characterized in that: The invention comprises a boiler (1), an air distribution plate (2), a fixing frame (31) and an impeller (32), wherein the boiler (1) is provided with a receiving chamber (11), the air distribution plate (2) is fixedly connected to the inner wall of the receiving chamber (11), the air distribution plate (2) is arranged horizontally, a plurality of air caps (24) are connected to the air distribution plate (2), the air distribution plate (2) divides the receiving chamber (11) into a combustion chamber (111) and an air chamber (112), the combustion chamber (111) is arranged above the air distribution plate (2), and an air inlet (12) is provided on a side wall of the boiler (1), the air inlet (12) is connected to a combustion chamber (111) and a combustion chamber (112). A wind chamber (112), wherein the fixing frame (31) is fixedly connected to the inner wall of the wind chamber (112), the height of the fixing frame (31) is greater than the height of the air inlet (12), the impeller (32) is coaxially fixedly connected to a drive shaft (321), the drive shaft (321) is rotatably connected to the fixing frame (31) around its own axis, the rotation axis of the drive shaft (321) is vertical, a plurality of impellers (32) are provided, the plurality of impellers (32) are evenly spaced along the width direction of the wind chamber (112), and adjacent drive shafts (321) are connected via a synchronizing member (33).

2. The circulating fluidized bed boiler air distribution system according to claim 1, characterized in that: The synchronous component (33) comprises a synchronous wheel (331) and a synchronous belt (332); the synchronous wheel (331) is coaxially fixedly connected to the drive shaft (321); and the synchronous belt (332) is sleeved on the outer circumference of two adjacent synchronous wheels (331).

3. The circulating fluidized bed boiler air distribution system according to claim 1, characterized in that: The plurality of impellers (32) are evenly spaced along the length direction of the wind chamber (112).

4. The circulating fluidized bed boiler air distribution system according to claim 1, characterized in that: The height of the bottom wall of the air chamber (112) increases as it moves away from the air inlet (12).

5. The circulating fluidized bed boiler air distribution system according to claim 1, characterized in that: The outer wall of the boiler (1) is provided with a feed port (13), the feed port (13) being connected to the combustion chamber (111), and a plurality of the feed ports (13) are provided, and the plurality of the feed ports (13) are evenly divided into two groups, the two groups of the feed ports (13) are respectively close to the two ends of the air distribution plate (2) in the width direction, and each group of the feed ports (13) is evenly spaced along the length direction of the air distribution plate (2).

6. The circulating fluidized bed boiler air distribution system according to claim 5, characterized in that: The opening of the feed port (13) in the combustion chamber (111) faces the air distribution plate (2).

7. The circulating fluidized bed boiler air distribution system according to claim 6, characterized in that: Along the width direction of the air distribution plate (2), the air distribution plate (2) is provided with a first air distribution area (21), a second air distribution area (22) and a third air distribution area (23) in sequence; the density of the air hoods (24) in the first air distribution area (21) is greater than the density of the air hoods (24) in the second air distribution area (22); and the density of the air hoods (24) in the third air distribution area (23) is greater than the density of the air hoods (24) in the second air distribution area (22).

8. The circulating fluidized bed boiler air distribution system according to claim 7, characterized in that: The plurality of wind hoods (24) are distributed in an array. Along the length direction of the wind distribution plate (2), the plurality of wind hoods (24) are evenly spaced. Along the width direction of the wind distribution plate (2), the spacing between adjacent wind hoods (24) in the second wind distribution area (22) is smaller than the spacing between adjacent wind hoods (24) in the first wind distribution area (21), and the spacing between adjacent wind hoods (24) in the second wind distribution area (22) is smaller than the spacing between adjacent wind hoods (24) in the third wind distribution area (23).

9. The circulating fluidized bed boiler air distribution system according to claim 8, characterized in that: The spacing between adjacent wind hoods (24) in the first wind distribution area (21) is equal to the spacing between adjacent wind hoods (24) in the third wind distribution area (23).

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