Cooling structure of pulverized coal burner

Abstract

The invention discloses a cooling structure of a pulverized coal burner, relates to the technical field of pulverized coal nozzle cooling, and aims to solve the problems that when an existing pulverized coal burner stops running, no primary air flows in a nozzle and a primary air pipe for cooling, and the pulverized coal nozzle and even the primary air pipe are easily burnt out due to flue gas backflow caused by intense radiant heat in a furnace and pressure fluctuation of a hearth. Comprising a primary air pipe, a secondary air pipe, a cooling tuyere cover plate and a wear-resistant plug block, the primary air pipe is installed in the secondary air pipe, a cooling air opening is formed in the primary air pipe, a cooling air opening cover plate capable of being opened and closed is installed on the cooling air opening, and the cooling air opening cover plate is used for guiding air in the secondary air pipe into the primary air pipe after being opened. Cold air in the secondary air pipe is introduced into the primary air pipe to achieve cooling of the primary air pipe and the nozzle.

Description

Technical Field

[0001] The invention relates to the technical field of pulverized coal nozzle cooling, and in particular to a pulverized coal burner cooling structure. Background Art

[0002] Pulverized coal boiler is a kind of boiler equipment which uses pulverized coal as fuel. Pulverized coal boiler has the advantages of high combustion rate, energy saving, simple start and stop, etc. It is composed of furnace, burner, ignition device, etc.

[0003] The burner is the main combustion equipment of the pulverized coal boiler. Its function is to ensure that the fuel and the combustion air are fully mixed when entering the furnace. Timely ignition and stable combustion. The air sent into the boiler through the burner is reasonably organized and sent in separately according to the principle of being beneficial to ignition and combustion. According to the different functions of the sent air, the sent air can be divided into primary air and secondary air. The primary air is the air sent into the burner with the pulverized coal, and the secondary air is the air sent in after the pulverized coal is ignited.

[0004] Pulverized coal boilers are usually equipped with multiple coal mills according to their capacity, and usually one coal mill and the corresponding pulverized coal burner are in standby state. When the pulverized coal burner is out of service, there is no primary air flow cooling in the nozzle and primary air duct. The strong radiant heat in the furnace and the flue gas reflux caused by the pressure fluctuation in the furnace can easily cause the pulverized coal nozzle and even the primary air duct to burn, affecting the safe operation of the unit and causing economic losses. Summary of the invention

[0005] In order to solve the problem that when the existing pulverized coal burner is shut down, there is no primary air flow cooling in the nozzle and the primary air duct, and the smoke reflux caused by the strong radiation heat in the furnace and the furnace pressure fluctuation can easily lead to the burning of the pulverized coal nozzle and even the primary air duct, the present invention further provides a pulverized coal burner cooling structure to solve the problems raised in the above background technology.

[0006] The technical solution of the present invention is:

[0007] A pulverized coal burner cooling structure comprises a primary air duct, a secondary air duct, a cooling air inlet cover plate and a wear-resistant plug;

[0008] The primary air duct is installed in the secondary air duct, and a cooling air outlet is provided on the primary air duct. A cooling air outlet cover that can be opened and closed is installed on the cooling air outlet. When the cooling air outlet cover is opened, it is used to introduce the air in the secondary air duct into the primary air duct. A wear-resistant plug is installed at the lower end of the cooling air outlet cover, and the windward part of the wear-resistant plug is set in a wedge shape;

[0009] Furthermore, a plurality of cooling air outlets are circumferentially opened on the side wall of the primary air duct, and a cooling air outlet cover is installed on each cooling air outlet.

[0010] Furthermore, the cooling air outlet cover is hinged to the cooling air outlet via a hinge seat, and the cooling air outlet cover opens in the direction of the incoming air from the secondary air duct.

[0011] Furthermore, a driving crank is fixed at the hinge of the cooling air outlet cover plate, and a pull rod is hinged on the driving crank.

[0012] Furthermore, a tie rod sleeve is fixed on the primary air duct, the tie rod passes through and is slidably connected in the tie rod sleeve, and a fixing piece for fixing the tie rod is installed on the tie rod sleeve.

[0013] Furthermore, the fixing member is a tightening screw threadedly connected to the pull rod sleeve.

[0014] Furthermore, an arc-shaped air guide portion is provided on the secondary air duct, and the arc-shaped air guide portion is used to guide the secondary air in the secondary air duct to the cooling air outlet.

[0015] Furthermore, a sealing gasket is provided at the lower end of the cooling air outlet cover plate.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. A cooling structure for a pulverized coal burner, wherein a secondary air duct is installed outside a primary air duct, a cooling air port is provided on the primary air duct for allowing the secondary air to enter the primary air duct, and a cooling air port cover that can be opened and closed is installed on the cooling air port. The cooling air port cover can be opened in the direction of the incoming air from the secondary air duct. When the cooling air port cover is opened, the cold air in the secondary air duct passes through the cooling air port and enters the primary air duct. The cooling air port cover has a drainage effect due to its inclined shape, and the cold air is introduced into the primary air duct to cool the primary air duct and the nozzle. When the burner is in a standby state and there is no primary air flow cooling in the burner, the secondary air enters the primary air duct through the cooling air port, and continues to enter the furnace through the nozzle, cooling the primary air duct and the nozzle to prevent them from burning. The amount of cold air entering can be adjusted by controlling the opening angle of the cooling air port cover to achieve different cooling effects.

[0018] 2. A wear-resistant plug is installed at the lower end of the cooling air outlet cover. The wear-resistant plug is used to protect the cooling air outlet cover. After the cooling air outlet cover is closed, it reduces the erosion of the cooling air outlet cover and the cooling air outlet by the high-speed coal powder in the primary air duct. The windward part of the wear-resistant plug is set to be wedge-shaped. When the cooling air outlet cover is opened, the wedge-shaped part of the wear-resistant plug can play a wind-guiding effect.

[0019] 3. A pull rod is provided to push the cooling air vent cover to rotate. The pull rod pushes the cooling air vent cover in the secondary air duct to open and close, thereby realizing the connection and disconnection of cooling air and the adjustment of the cooling air intake volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The overall structure diagram of the cooling structure of the pulverized coal burner Figure I ;

[0021] Figure 2 The overall structure diagram of the cooling structure of the pulverized coal burner Figure II ;

[0022] Figure 3 for Figure 1 Partial view of the cooling air vent cover at position Ⅰ in the closed state;

[0023] Figure 4 for Figure 1 Partial view of the cooling air vent cover at position Ⅰ in the middle with it open;

[0024] Figure 5 for Figure 1 Partial schematic diagram of point II in the middle.

[0025] In the figure: 1. primary air duct; 2. cooling air outlet; 3. secondary air duct; 4. cooling air outlet cover; 5. wear-resistant plug; 6. sealing gasket; 7. driving crank; 8. hinge seat; 9. pull rod; 10. pull rod sleeve; 11. fixing piece; 12. arc-shaped air guide part. DETAILED DESCRIPTION

[0026] Specific implementation method 1: See Figure 1-4 As shown, a pulverized coal burner cooling structure, this embodiment includes a primary air duct 1, a secondary air duct 3, a cooling air inlet cover plate 4 and a wear-resistant plug 5;

[0027] The primary air duct 1 is installed in the secondary air duct 3. A cooling air outlet 2 is opened on the primary air duct 1. A cooling air outlet cover 4 that can be opened and closed is installed on the cooling air outlet 2. When the cooling air outlet cover 4 is opened, it is used to introduce the air in the secondary air duct 3 into the primary air duct 1. A wear-resistant plug 5 is installed at the lower end of the cooling air outlet cover 4, and the windward part of the wear-resistant plug 5 is set to be wedge-shaped.

[0028] Specific implementation method 2: See Figure 3 and 4 As shown, the cooling air outlet cover plate 4 of this embodiment is hinged to the cooling air outlet 2 through a hinge seat 8 , and the cooling air outlet cover plate 4 opens in the direction of the incoming air from the secondary air duct 3 .

[0029] Furthermore, the pulverized coal is blown into the boiler through the primary air duct 1, and the secondary air duct 3 is used to adjust the temperature and oxygen content during the combustion process. The primary air duct 1 is nested in the secondary air duct 3, and the gap between the primary air duct 1 and the secondary air duct 3 forms a secondary air duct. The cooling air port 2 connects the secondary air duct 3 with the primary air duct 1, so that the cold air in the secondary air duct 3 enters the primary air duct 1, and cools the primary air duct 1 and the nozzle from the inside. When the burner is in the standby state and there is no primary air flow cooling in the burner, the secondary air enters the primary air duct 1 through the cooling air port 2, and continues to enter the furnace through the nozzle, so as to cool the primary air duct 1 and the nozzle and prevent them from burning. The cooling air port cover 4 is used to close and open the cooling air port 2. The flip angle of the cooling air port cover 4 after opening is an acute angle. After the cooling air port cover 4 is opened (such as Figure 4 As shown in the figure, the cooling air outlet cover plate 4 blocks part of the secondary air duct 3, changes the flow direction of the secondary air in the secondary air duct 3, and the secondary air is guided to the cooling air outlet 2 along the plate body, thereby achieving the diversion effect and increasing the air intake efficiency into the primary air duct 1. The wear-resistant plug 5 is installed at the lower end of the cooling air outlet cover plate 4, and the windward side of the wear-resistant plug 5 is set to a wedge shape, which improves the air guide efficiency after the cooling air outlet cover plate 4 is opened. The wear-resistant plug 5 has the same contour as the cooling air outlet 2. After the cooling air outlet cover plate 4 is closed, the wear-resistant plug 5 blocks the cooling air outlet 2, and the lower end surface of the wear-resistant plug 5 constitutes the inner wall of the primary air duct 1 to reduce the scouring of the cooling air outlet 2 and the cooling air outlet cover plate 4 by coal powder.

[0030] Specific implementation method three: see Figure 1 As shown, a plurality of cooling air ports 2 are circumferentially opened on the side wall of the primary air duct 1 of the present embodiment, and a cooling air port cover plate 4 is installed on each cooling air port 2 .

[0031] Furthermore, the cooling air outlets 2 are evenly distributed on the side wall of the primary air duct 1, so that the secondary air enters the primary air duct 1 more evenly, and the primary air duct 1 and the nozzle are cooled more evenly, preventing the local temperature difference between the primary air duct 1 and the nozzle from being too large and causing expansion and cracking.

[0032] Specific implementation method four: see Figure 3 and 4 As shown, a driving crank 7 is fixed at the hinge of the cooling air port cover plate 4 in this embodiment, and a pull rod 9 is hinged on the driving crank 7.

[0033] Furthermore, the driving crank 7 can rotate around the hinge seat 8 with the cooling air vent cover 4, and the pull rod 9 drives the cooling air vent cover 4 to rotate by pushing the driving crank 7. When the pull rod 9 is pushed to the left, the pull rod 9 drives the driving crank 7 to rotate counterclockwise, and the driving crank 7 drives the cooling air vent cover 4 to rotate counterclockwise to complete the opening. When the pull rod 9 is pulled to the right, the pull rod 9 drives the driving crank 7 to rotate clockwise, and the driving crank 7 drives the cooling air vent cover 4 to rotate clockwise to complete the closing. The opening angle of the cooling air vent cover 4 is controlled by controlling the push-pull distance of the pull rod 9, and the pull rod 9 is fixed to achieve the normally open or normally closed state of the cooling air vent cover 4.

[0034] Specific implementation method five: see Figure 5 As shown, a tie rod sleeve 10 is fixed on the primary air duct 1 of this embodiment, and the tie rod 9 passes through and is slidably connected in the tie rod sleeve 10 . A fixing piece 11 for fixing the tie rod 9 is installed on the tie rod sleeve 10 .

[0035] Specific implementation method six: see Figure 5 As shown, the fixing member 11 of this embodiment is a tightening screw threadedly connected to the pull rod sleeve 10.

[0036] Furthermore, the rod sleeve 10 is used to cooperate with the fixing piece 11 to complete the fixing of the rod 9. When in use, the cooling air vent cover plate 4 is opened to the set position by adjusting the rod 9, and the fixing piece 11 is tightened to fix the rod sleeve 10 and the rod 9, thereby completing the fixing of the cooling air vent cover plate 4. When the angle of the cooling air vent cover plate 4 needs to be adjusted, the fixing piece 11 is loosened and tightened, so that the rod 9 can slide in the rod sleeve 10, and the rod 9 is pushed to complete the adjustment of the angle of the cooling air vent cover plate 4.

[0037] Specific implementation method seven: See Figure 2 As shown, the secondary air duct 3 of this embodiment is provided with an arc-shaped air guide portion 12 , and the arc-shaped air guide portion 12 is used to guide the secondary air in the secondary air duct 3 to the cooling air port 2 .

[0038] Furthermore, the diameter of the secondary air duct 3 gradually decreases from the air inlet to the cooling air outlet 2, forming an arc-shaped air guide portion 12, so that the secondary air flows to the surface of the primary air duct 1 when passing through the cooling air outlet 2. When the cooling air outlet cover 4 is opened, the secondary air flows to the surface of the primary air duct 1 through the arc-shaped air guide portion 12, and passes through the cooling air outlet 2 into the primary air duct 1, achieving an air guide effect.

[0039] Specific implementation method eight: See Figure 3 and 4 As shown, a sealing gasket 6 is provided at the lower end of the cooling air port cover plate 4 of this embodiment.

[0040] Furthermore, the sealing gasket 6 is arranged at the contact surface between the cooling air inlet cover plate 4 and the outer wall of the primary air duct 1, and surrounds the wear-resistant plug 5. The sealing gasket 6 is used to completely seal the cooling air inlet cover plate 4 and the primary air duct 1 when the cooling air inlet cover plate 4 is closed, so as to prevent the coal powder in the primary air duct 1 from entering the secondary air duct 3.

Claims

1. A pulverized coal burner cooling structure, characterized in that: It comprises a primary air duct (1), a secondary air duct (3), a cooling air outlet cover plate (4) and a wear-resistant plug (5); The primary air duct (1) is installed in the secondary air duct (3), the primary air duct (1) is provided with a cooling air outlet (2), the cooling air outlet (2) is provided with an openable and closable cooling air outlet cover (4), the cooling air outlet cover (4) is used to introduce the air in the secondary air duct (3) into the primary air duct (1) after opening, the lower end of the cooling air outlet cover (4) is provided with a wear-resistant plug (5), and the windward part of the wear-resistant plug (5) is set to be wedge-shaped.

2. The pulverized coal burner cooling structure according to claim 1, characterized in that: A plurality of cooling air ports (2) are circumferentially formed on the side wall of the primary air duct (1), and a cooling air port cover plate (4) is installed on each cooling air port (2).

3. The pulverized coal burner cooling structure according to claim 2, characterized in that: The cooling air outlet cover plate (4) is hinged to the cooling air outlet (2) via a hinge seat (8), and the cooling air outlet cover plate (4) opens in the direction of the incoming air from the secondary air duct (3).

4. The pulverized coal burner cooling structure according to claim 3 is characterized in that: A driving crank (7) is fixed at the hinge of the cooling air vent cover plate (4), and a pull rod (9) is hinged on the driving crank (7).

5. The pulverized coal burner cooling structure according to claim 4, characterized in that: A tie rod sleeve (10) is fixed on the primary air duct (1), the tie rod (9) passes through and is slidably connected in the tie rod sleeve (10), and a fixing piece (11) for fixing the tie rod (9) is installed on the tie rod sleeve (10).

6. The pulverized coal burner cooling structure according to claim 5, characterized in that: The fixing member (11) is a tightening screw threadedly connected to the pull rod sleeve (10).

7. The pulverized coal burner cooling structure according to claim 1, characterized in that: The secondary air duct (3) is provided with an arc-shaped air guide portion (12), and the arc-shaped air guide portion (12) is used to guide the secondary air in the secondary air duct (3) to the cooling air outlet (2).

8. The pulverized coal burner cooling structure according to claim 1, characterized in that: A sealing gasket (6) is provided at the lower end of the cooling air port cover plate (4).

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