A coal feeding and equalizing device for a circulating fluidized bed boiler and its operation method

Abstract

The present invention discloses a coal feeding and equalizing device for a circulating fluidized bed boiler and its operation method, which includes a raw coal bunker. The raw coal bunker is connected to a central coal feeder, the central coal feeder is connected to a weighing coal feeder, the outlet of the weighing coal feeder is connected to a #1 chain coal feeder, and the outlet of the #1 chain coal feeder enters the boiler #1 coal feeding port and a #2 chain coal feeder respectively through an electric distributor; the #2 chain coal feeder is equipped with a belt scale and enters the boiler #2 coal feeding port and a #3 chain coal feeder respectively through the electric distributor. The #3 chain coal feeder is equipped with a belt scale, and the raw coal at the outlet of the #3 chain coal feeder is connected to the boiler #3 coal feeding port. The present invention can accurately achieve uniform coal feeding at the 3 coal feeding ports of each coal feeding line of the circulating fluidized bed boiler, control the total coal amount of each coal feeding line to be basically the same, so as to ensure uniform coal feeding at each coal feeding port of the boiler, ensure the overall heat balance and material balance of the boiler, and improve the uniformity of the temperature distribution in the furnace.

Description

Technical Field

[0001] The present invention relates to the technical field of circulating fluidized bed boiler operation, and particularly relates to a coal feeding equalizing device for a circulating fluidized bed boiler and an operation method thereof. Background Art

[0002] The Central Economic Work Conference pointed out that the gradual phasing out of traditional energy must be based on the safe and reliable substitution of new energy. Under the current circumstances, it is necessary to focus on the basic national condition of mainly relying on coal and do a good job in the clean and efficient utilization of coal, promote the optimal combination of coal and new energy, and increase the consumption capacity of new energy.

[0003] Coal-fired power generation occupies a dominant position in China's power industry and is also the main way of coal utilization in China. Although China is rich in coal resources and has a wide variety of coal types, the proportion of high-sulfur low-quality coal with a high ash content is relatively large. In addition, a large amount of low-calorie by-products such as washed medium coal, coal gangue, and coal slime are generated during coal mining and processing. These low-quality coals and low-calorie difficult-to-burn fuels are difficult to be effectively applied in traditional pulverized coal combustion technology. The fuel applicability of circulating fluidized bed combustion technology is wide, and stable combustion can still be ensured during the combustion of low-quality coal and low-calorie fuels. Circulating fluidized bed boiler technology has gradually been applied in the industrial field. With the unremitting efforts of scientific research personnel, circulating fluidized bed boiler technology has achieved certain development results and has gradually become a high-efficiency and low-pollution clean coal combustion technology currently used in China.

[0004] Nowadays, the capacity of circulating fluidized bed boilers is constantly increasing, and more super (ultra) critical circulating fluidized bed units are put into operation. From the operation conditions of many large circulating fluidized bed boilers, the temperature distribution in the furnace is uneven, especially the horizontal diffusion is significantly uneven, resulting in uneven heat load in the furnace. The heating surface may undergo thermal stress fatigue deformation, increasing the wear of the pipe wall, and finally causing tube explosion. At the same time, there will be local overheating in the furnace and heating surface, and there may be risks of coking and tube explosion.

[0005] For large circulating fluidized bed boilers, since each coal feeding line corresponds to 3 coal feeding ports of the boiler, there is a situation of uneven coal quantity distribution among the coal feeding ports. The uneven distribution of coal quantity will lead to uneven bed temperature, thus affecting the combustion in the furnace. Therefore, ensuring uniform coal feeding is of great significance to the overall heat balance and material balance of the circulating fluidized bed boiler. Summary of the Invention

[0006] The technical problem to be solved by the present invention is: to provide a coal feeding equalizing device for a circulating fluidized bed boiler and an operation method thereof, to achieve uniform coal feeding at the 3 coal feeding ports of each coal feeding line of the circulating fluidized bed boiler, ensure the overall heat balance and material balance of the boiler, and improve the uniformity of the temperature distribution in the furnace, so as to solve the technical problems existing in the prior art.

[0007] The technical solution adopted by the present invention is as follows: A coal feeding and equalizing device for a circulating fluidized bed boiler, which includes a raw coal bunker. The raw coal bunker is connected to a central coal feeder. The central coal feeder is connected to a weighing coal feeder through a coal dropping pipe. The weighing coal feeder is equipped with a belt scale 1 for weighing the total coal feeding amount. The outlet of the weighing coal feeder is connected to a #1 chain coal feeder through a coal dropping pipe 1. An electric distributor 1 is installed at the outlet of the #1 chain coal feeder. The electric distributor 1 divides the raw coal into two parts, which respectively enter the coal feeding port of boiler #1 and the #2 chain coal feeder. A part of the raw coal enters the furnace through a coal dropping pipe 2 connected to the coal feeding port of boiler #1 and a pneumatic gate valve 1. The other part of the raw coal enters the #2 chain coal feeder. The #2 chain coal feeder is equipped with a belt scale 2 for weighing the coal feeding amount of the #2 chain coal feeder. An electric distributor 2 is installed at the outlet of the #2 chain coal feeder. The electric distributor 2 divides the raw coal into two parts, which respectively enter the coal feeding port of boiler #2 and the #3 chain coal feeder. A part of the raw coal enters the furnace through a coal dropping pipe 3 connected to the coal feeding port of boiler #2 and a pneumatic gate valve 2. The other part of the raw coal enters the #3 chain coal feeder. The #3 chain coal feeder is equipped with a belt scale 3 for weighing the coal feeding amount of the #3 chain coal feeder. The raw coal at the outlet of the #3 chain coal feeder enters the furnace through a coal dropping pipe 4 connected to the coal feeding port of boiler #3 and a pneumatic gate valve 3.

[0008] Among them, the electric distributor 1 is installed above the #1 chain coal feeder. The electric distributor 1 is slidably connected to an adjustment table through a guide rail slider 1. The adjustment table is slidably connected to a support through a guide rail slider 2. The structure of the electric distributor 1 is in the shape of a right triangle, including an alloy high manganese chromium plow head welded at the bottom of the front end. The angle of the alloy high manganese chromium plow head is 25 - 35° (preferably 30°). The bottom of the electric distributor 1 is riveted with wear-resistant rubber plates, a support truss is welded at the rear end, and a guide rail slider 1 is welded at the rear bottom. The guide rail slider 1 is parallel to the hypotenuse of the electric distributor 1. The position of the electric distributor 1 on the #1 chain coal feeder can be controlled by controlling the movement of the guide rail slider 1, so as to control the amount of raw coal entering the coal feeding port of boiler #1 and the #2 chain coal feeder. The height of the adjustment table and the electric distributor can be controlled by controlling the movement of the guide rail slider, so as to achieve the purpose of separating the electric distributor 1 from the #1 chain coal feeder. The structure and installation components of the electric distributor 2 are the same as those of the electric distributor 1.

[0009] Advantages of the present invention: Compared with the existing coal feeding equalization technology for circulating fluidized bed boilers, the biggest feature of the present invention is that it can accurately achieve uniform coal feeding at the three coal feeding ports of each coal feeding line of the circulating fluidized bed boiler. By controlling the total coal amount of each coal feeding line to be basically the same, uniform coal feeding at each coal feeding port of the boiler can be ensured, the overall heat balance and material balance of the boiler can be guaranteed, and the uniformity of the temperature distribution in the furnace can be improved. Secondly, the coal distribution process of the electric distributor is carried out at the tail of the chain feeder. After the raw coal enters the coal feeding port of the boiler, it directly enters the furnace for combustion, and there is no need to use a traditional electric slide gate to control the coal feeding amount, thus avoiding coal blockage at the coal feeding port and coal dropping pipe of the boiler. Finally, the actions of the electric distributor are all controlled electrically. According to the total coal feeding amount G1 of the weighing feeder, the coal feeding amount G2 of the #2 chain feeder, and the coal feeding amount G3 of the #3 chain feeder, the coal amounts at the three coal feeding ports of each coal feeding line can be calculated in real time, and logical configuration can be carried out in the DCS to achieve automatic control. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 FIG. is a schematic diagram of a coal feeding equalization device for a circulating fluidized bed boiler provided by the invention.

[0011] Figure 2 FIG. is a schematic diagram of the electric distributor provided by the present invention.

[0012] Figure 3 FIG. is a schematic diagram of the equal coal feeding adjustment state of the electric distributor provided by the present invention.

[0013] Figure 4 FIG. is a schematic diagram of the state where the electric distributor is lifted away from the chain feeder provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0014] The present invention will be further introduced below in conjunction with the accompanying drawings and specific embodiments.

[0015] Embodiment 1: As Figures 1-4As shown in the figure, a coal feeding and equalizing device for a circulating fluidized bed boiler includes a raw coal bunker 1. The raw coal bunker 1 is connected to a central coal feeder 2. The central coal feeder 2 is connected to a weighing coal feeder 4 through a coal dropping pipe 1 3. The weighing coal feeder 4 is equipped with a belt scale 1 5 for weighing the total coal feeding amount G1. The outlet of the weighing coal feeder 4 is connected to a #1 chain coal feeder 7 through a coal dropping pipe 2 6. An electric distributor 1 9 is installed at the outlet of the #1 chain coal feeder 7. The electric distributor 1 9 divides the raw coal into two parts, which respectively enter the coal feeding port 8 of the boiler #1 and the #2 chain coal feeder 12. A part of the raw coal enters the furnace through a coal dropping pipe 3 10 connected to the coal feeding port 8 of the boiler #1 and a pneumatic gate valve 1 11. Another part of the raw coal enters the #2 chain coal feeder 12. The #2 chain coal feeder 12 is equipped with a belt scale 2 13 for weighing the coal feeding amount G2 of the #2 chain coal feeder 12. An electric distributor 2 15 is installed at the outlet of the #2 chain coal feeder 12. The electric distributor 2 15 divides the raw coal into two parts, which respectively enter the coal feeding port 14 of the boiler #2 and the #3 chain coal feeder 19. A part of the raw coal enters the furnace through a coal dropping pipe 4 16 connected to the coal feeding port 14 of the boiler #2 and a pneumatic gate valve 2 17. Another part of the raw coal enters the #3 chain coal feeder 19. The #3 chain coal feeder 19 is equipped with a belt scale 3 20 for weighing the coal feeding amount G3 of the #3 chain coal feeder 19. The raw coal at the outlet of the #3 chain coal feeder 19 enters the furnace through a coal dropping pipe 5 22 connected to the coal feeding port 21 of the boiler #3 and a pneumatic gate valve 3 23.

[0016] Among them, the structures and working principles of the electric distributor 1 9 and the electric distributor 2 15 are the same. As Figure 2 shown, the electric distributor 1 9 is installed above the #1 chain coal feeder 7. The electric distributor 1 9 is slidably connected to an adjustment table 29 through a guide rail slider 1 28. The adjustment table 29 is slidably connected to a support 32 through a guide rail slider 2 30. The structure of the electric distributor 1 9 is in the shape of a right triangle, including an alloy high manganese chromium plow head 24 welded to the bottom of the front end. The angle of the alloy high manganese chromium plow head 24 is about 30°. The bottom of the electric distributor 9 is riveted with wear-resistant rubber plates 26, and a support truss 27 is welded to the rear end. A guide rail slider 1 28 is welded to the bottom rear end. The guide rail slider 1 28 is parallel to the hypotenuse of the electric distributor 1 9. As Figure 3 shown in (a), (b) and (c) in the figure, the position of the electric distributor 1 9 on the #1 chain coal feeder 7 can be controlled by controlling the movement of the guide rail slider 1 28, so as to control the amount of raw coal entering the coal feeding port 8 of the boiler #1 and the #2 chain coal feeder 12. As Figure 4 shown in (a), (b) and (c) in the figure, the height of the adjustment table 29 and the electric distributor 9 1 can be controlled by controlling the movement of the guide rail slider 2 30, so as to achieve the purpose of separating the electric distributor 1 9 from the #1 chain coal feeder 7.

[0017] Embodiment 2: An operation method of a coal feeding equalizing device for a circulating fluidized bed boiler comprises the following steps:

[0018] Step 1: The total coal feeding amount G1 of the weighing coal feeder 4 is the total coal feeding amount entering the furnace through the coal feeding port 8 of Boiler #1, the coal feeding port 14 of Boiler #2, and the coal feeding port 21 of Boiler #3; the coal feeding amount G2 of the #2 chain coal feeder 12 is the coal feeding amount entering the furnace through the coal feeding port 14 of Boiler #2 and the coal feeding port 21 of Boiler #3; the coal feeding amount of the #3 chain coal feeder 19 is G3, which is the coal feeding amount entering the furnace through the coal feeding port 21 of Boiler #3. Therefore, it can be known that the coal feeding amount entering the furnace through the coal feeding port 21 of Boiler #3 is G3, the coal feeding amount entering the furnace through the coal feeding port 14 of Boiler #2 is G2 - G3, and the coal feeding amount entering the furnace through the coal feeding port 8 of Boiler #1 is G1 - G2. When G3, G2 - G3, and G1 - G2 are approximately equal, the coal feeding equalization of the circulating fluidized bed boiler is achieved.

[0019] Step 2: The total coal feeding amount passing through the weighing coal feeder 4 is G1. Control the position of the electric distributor 9 on the #1 chain coal feeder 7 (as shown in (a), (b), and (c) below), and control the coal feeding amount G2 entering the #2 chain coal feeder 12 to be about 2 / 3 of G1; control the position of the electric distributor 15 on the #2 chain coal feeder 12 (as shown in (a), (b), and (c) below), and control the coal feeding amount G3 entering the #3 chain coal feeder 19 to be about half of G2, so as to make the coal feeding amounts of the coal feeding port 8 of Boiler #1, the coal feeding port 14 of Boiler #2, and the coal feeding port 21 of Boiler #3 basically equal, and further achieve the coal feeding equalization of the circulating fluidized bed boiler. Figure 3 Figure 3 Figure 3 Figure 3

[0020] Step 3: The actions of the guide rail slider 28 of the electric distributor 9 and the guide rail slider 30 of the electric distributor 15 are both electrically controlled. According to the coal feeding amounts of the coal feeding port 8 of Boiler #1, the coal feeding port 14 of Boiler #2, and the coal feeding port 21 of Boiler #3, perform DCS logic configuration, and convert the deviation of the coal feeding amounts of the 3 coal feeding ports of each coal feeding line into instructions for the guide rail sliders to achieve automatic control.

[0021] Compared with the existing coal feeding equalization technology for circulating fluidized bed boilers, the biggest feature of the present invention is that it can accurately achieve uniform coal feeding at the three coal feeding ports of each coal feeding line of the circulating fluidized bed boiler. By controlling the total coal amount of each coal feeding line to be basically the same, it is possible to ensure uniform coal feeding at each coal feeding port of the boiler, ensure the overall heat balance and material balance of the boiler, and improve the uniformity of the temperature distribution in the furnace. Secondly, the coal distribution process of the electric distributor is carried out at the tail of the chain feeder. After the raw coal enters the coal feeding port of the boiler, it directly enters the furnace for combustion, and there is no need to use the traditional electric slide gate to control the coal feeding amount, thus avoiding coal blockage at the coal feeding port and the coal dropping pipe of the boiler. Finally, the actions of the electric distributor are all controlled electrically. According to the total coal feeding amount G1 of the weighing feeder, the coal feeding amount G2 of the #2 chain feeder, and the coal feeding amount G3 of the #3 chain feeder, the coal amount at the three coal feeding ports of each coal feeding line can be calculated in real time, and logical configuration can be carried out in the DCS to achieve automatic control.

[0022] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claimed rights.

Claims

1. A coal feeding and equalizing device for a circulating fluidized bed boiler, characterized in that: It includes a raw coal bunker (1), the raw coal bunker (1) is connected to a central coal feeder (2), the central coal feeder (2) is connected to a weighing coal feeder (4) through a first coal dropping pipe (3), the outlet of the weighing coal feeder (4) is connected to a #1 chain coal feeder (7) through a second coal dropping pipe (6), an electric distributor one (9) is installed at the outlet of the #1 chain coal feeder (7), the electric distributor one (9) is respectively connected to the #1 coal feeding port (8) of the boiler and a #2 chain coal feeder (12), the #1 coal feeding port (8) of the boiler is successively connected with a third coal dropping pipe (10) and a pneumatic slide gate one (11) entering the furnace, the #2 chain coal feeder (12) is equipped with a second belt scale (13), an electric distributor two (15) is installed at the outlet of the #2 chain coal feeder (12), the electric distributor two (15) is respectively connected to the #2 coal feeding port (14) of the boiler and a #3 chain coal feeder (19), a fourth coal dropping pipe (16) connected to the #2 coal feeding port (14) of the boiler and a pneumatic slide gate two (17) entering the furnace, the #3 chain coal feeder (19) is equipped with a third belt scale (20), the outlet of the #3 chain coal feeder (19) is successively connected with the #3 coal feeding port (21) of the boiler, a fifth coal dropping pipe (22) and a pneumatic slide gate three (23) entering the furnace; the weighing coal feeder (4) is equipped with a first belt scale (5); the electric distributor one (9) and the electric distributor two (15) have the same structure and installation components, the electric distributor one (9) is installed above the #1 chain coal feeder (7), the electric distributor one (9) is slidably connected to an adjustment table (29) through a first guide rail slider (28), and the adjustment table (29) is slidably connected to a support (32) through a second guide rail slider (30); the operation method of the coal feeding equalization device for the circulating fluidized bed boiler is as follows: the total coal feeding amount passing through the weighing coal feeder is G1, control the position of the electric distributor one on the #1 chain coal feeder, and control the coal feeding amount G2 entering the #2 chain coal feeder to be 2 / 3 of G1; control the position of the electric distributor two on the #2 chain coal feeder, and control the coal feeding amount G3 entering the #3 chain coal feeder to be half of G2, so as to make the coal feeding amounts at the #1 coal feeding port, the #2 coal feeding port and the #3 coal feeding port of the boiler basically equal, and further realize the equalization of coal feeding for the circulating fluidized bed boiler.

2. The coal feeding and equalizing device for a circulating fluidized bed boiler according to claim 1, wherein: The electric distributor one (9) is in the shape of a right triangle, including an alloy high manganese chromium plow head (24) welded at the bottom of the front end, the angle of the alloy high manganese chromium plow head (24) is 25° - 35°, the bottom of the electric distributor one (9) is riveted with wear-resistant rubber plates (26), a support truss (27) is welded at the rear end, a first guide rail slider (28) is welded at the bottom rear end, and the first guide rail slider (28) is parallel to the hypotenuse of the electric distributor one (9).

3. The coal feeding and equalizing device for a circulating fluidized bed boiler according to claim 2, characterized in that: The angle of the alloy high manganese chromium plow head (24) is 30°.

4. The operating method of a coal feeding and equalizing device for a circulating fluidized bed boiler according to any one of claims 1-3, characterized in that: The method is as follows: The total coal feeding amount G1 of the weighing coal feeder is the total coal feeding amount entering the furnace from the coal feeding ports of Boiler #1, Boiler #2, and Boiler #3; the coal feeding amount G2 of the #2 chain coal feeder is the coal feeding amount entering the furnace from the coal feeding ports of Boiler #2 and Boiler #3; the coal feeding amount of the #3 chain coal feeder is G3, which is the coal feeding amount entering the furnace from the coal feeding port of Boiler #3; the coal feeding amount entering the furnace from the coal feeding port of Boiler #3 is G3, the coal feeding amount entering the furnace from the coal feeding port of Boiler #2 is G2 - G3, and the coal feeding amount entering the furnace from the coal feeding port of Boiler #1 is G1 - G2; control G3, G2 - G3, and G1 - G2 to be approximately equal. The specific operation method is: The total coal feeding amount passing through the weighing coal feeder is G1. Control the position of the electric diverter one on the #1 chain coal feeder to control the coal feeding amount G2 entering the #2 chain coal feeder to be 2 / 3 of G1; control the position of the electric diverter two on the #2 chain coal feeder to control the coal feeding amount G3 entering the #3 chain coal feeder to be half of G2, so as to make the coal feeding amounts at the coal feeding ports of Boiler #1, Boiler #2, and Boiler #3 basically equal, and further achieve the even distribution of coal feeding for the circulating fluidized bed boiler.

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