A device applied to denitration during startup and shutdown

Abstract

The present invention relates to the technical field of start-up and shutdown, in particular to a device applied to denitration during start-up and shutdown, including a horizontal electric heater, on which an intake pipe, an outlet pipe and a slag discharge pipe communicating with the inner cavity of the horizontal electric heater are provided. The intake pipe is located at one end of the horizontal electric heater, the outlet pipe is located at the top of the horizontal electric heater, and the slag discharge pipe is located at the bottom of the horizontal electric heater. It further includes a spray head provided on the side wall of the inner cavity of the horizontal electric heater and located above the intake pipe; wherein, a valve is provided on the slag discharge pipe; a closing mechanism, which includes a shielding part provided in the inner cavity of the horizontal electric heater, a driving component for driving the movement of the shielding part, and a lifting component for assisting the driving component to drive the shielding part to move. When the horizontal electric heater is being cleaned, through the closing mechanism, the intake pipe is closed, thereby avoiding water from entering the reactor interior through the intake pipe and reacting with the residual ammonia, causing corrosion of the pipeline and the reactor.

Description

Technical Field

[0001] The present invention relates to the technical field of start-up and shutdown, and in particular to a device applied to denitration during start-up and shutdown. Background Art

[0002] Currently, during start-up and shutdown operations and at low load sections, the denitration system needs to wait until the flue gas temperature reaches above 295 degrees Celsius before it can be put into use. Otherwise, there is a high risk of ammonia injection crystallization blocking the air duct.

[0003] Therefore, an electric heating system needs to be installed on the flue gas pipeline in front of the SCR reactor inlet. The flue gas flow direction in the SCR reactor is as follows: un-denitrified flue gas from the economizer of the boiler → inlet of the SCR system → ammonia injection grid → flue gas / ammonia mixer → horizontal electric heater → deflector → rectifying device → catalyst layer → outlet of the SCR reactor → inlet of the air preheater.

[0004] Among them, when the horizontal electric heater is used for a long time, its interior needs to be cleaned to achieve a better heating effect. In the prior art, when cleaning the horizontal electric heater, the end cover needs to be removed first, and then a nozzle is used for cleaning. The cleaning process is rather troublesome. In some technologies, nozzles are set on the horizontal heater to spray water for cleaning. However, in this way, during cleaning, since the inlet pipe of the horizontal heater is usually horizontally arranged at the end of the horizontal electric heater, water may flow into the flue gas / ammonia mixer from the inlet pipe, react with the remaining ammonia in the flue gas / ammonia mixer and the pipeline to generate ammonia water. Ammonia water is corrosive and can easily affect the pipeline or the mixer, thus affecting the use of the equipment. Therefore, a device applied to denitration during start-up and shutdown is proposed. Summary of the Invention

[0005] In view of the problem that during cleaning in the above or prior art, water may flow into the flue gas / ammonia mixer from the inlet pipe, react with the remaining ammonia in the flue gas / ammonia mixer and the pipeline to generate ammonia water, and ammonia water is corrosive and can easily affect the pipeline or the mixer, thus affecting the use of the equipment, the present invention is proposed.

[0006] Therefore, the object of the present invention is to provide a device applied to denitration during start-up and shutdown.

[0007] To solve the above technical problems, the present invention provides the following technical solutions: including,

[0008] A horizontal electric heater, which is provided with an inlet pipe, an outlet pipe and a slag discharge pipe communicating with the inner cavity of the horizontal electric heater. The inlet pipe is located at one end of the horizontal electric heater, the outlet pipe is located at the top of the horizontal electric heater, and the slag discharge pipe is located at the bottom of the horizontal electric heater. It also includes a nozzle provided on the side wall of the inner cavity of the horizontal electric heater and located above the inlet pipe;

[0009] Among them, a valve is provided on the slag discharge pipe;

[0010] A closing mechanism, which includes a shielding part arranged in the inner cavity of the horizontal electric heater, a driving component for driving the movement of the shielding part, and a lifting component for assisting the driving component to drive the shielding part to move.

[0011] The driving component includes a driving motor arranged on the horizontal electric heater. The output end of the driving motor extends into the inner cavity of the horizontal electric heater and is connected with a disc. A driving rod is connected to the side of the disc away from the driving motor;

[0012] The driving rod is near the edge of the disc.

[0013] The lifting component includes a bearing block arranged on the side of the disc away from the driving motor. A first sliding groove is formed in the bearing block, and the bearing block is connected with the shielding part through a vertical plate. It also includes two side plates installed in the inner cavity of the horizontal electric heater;

[0014] The end of the driving rod away from the disc slides through the first sliding groove;

[0015] The shielding part is located between the two side plates.

[0016] The bearing block is rectangular, and the two ends of the bearing block away from each other are respectively attached to the sides of the two side plates close to each other.

[0017] On the side of the side plate close to the bearing block, a second sliding groove and a third sliding groove are formed. The second sliding groove is communicated with the third sliding groove. The second sliding groove is inclined. A sliding rod is slidably arranged inside the second sliding groove. One end of the sliding rod penetrates out of the second sliding groove and is connected with the shielding part. The second sliding groove and the third sliding groove match the movement track of the sliding rod.

[0018] The shielding part includes a first shielding plate and a second shielding plate. A cross plate is connected to the first shielding plate, and the first shielding plate and the second shielding plate are connected through an adjusting component;

[0019] The second shielding plate is L-shaped, and the second shielding plate is connected to the end of the vertical plate away from the bearing block.

[0020] The sides of the first shielding plate and the second shielding plate away from the disc are flush with the sides of the side plates away from the inner wall of the horizontal electric heater, and the sides of the first shielding plate and the second shielding plate away from each other are respectively attached to the two side plates.

[0021] As a preferred solution of the device of the present invention applied to start-up and shutdown denitration, among them: the adjusting component includes a first inclined surface arranged at the bottom of the second shielding plate, a diversion block installed on the inner wall of the horizontal electric heater, and a second inclined surface arranged on the diversion block.

[0022] As a preferred embodiment of the device for starting and stopping denitration according to the present invention, wherein: the adjusting assembly further includes a telescopic rod connected to the first baffle, a spring sleeved on the surface of the telescopic rod, and both ends of the telescopic rod and the spring away from the first baffle are connected to the second baffle through folding plates.

[0023] As a preferred embodiment of the device for starting and stopping denitration according to the present invention, wherein: the end of the intake pipe at one end of the horizontal electric heater is provided with an arc surface, and the arc surface corresponds to the second chute.

[0024] The beneficial effects of the device for starting and stopping denitration according to the present invention: When the horizontal electric heater needs to be used, the driving assembly and the lifting assembly cooperate to drive the shielding part to close the nozzle, so that impurities in the gas will not adhere to the water outlet holes of the nozzle, thus causing the water outlet holes to be blocked. When the horizontal electric heater needs to be cleaned internally, the driving assembly and the lifting assembly cooperate to shield the intake pipe, avoiding water entering the flue gas / ammonia mixer from the intake pipe during the cleaning process and reacting with the residual ammonia in the flue gas / ammonia mixer and the pipeline to generate ammonia water. Ammonia water is corrosive and will corrode the pipeline or the mixer, thus affecting the use of the equipment. When the intake pipe is closed and the valve on the slag discharge pipe is closed, at this time, the water sprayed by the nozzle can be mixed with the cleaning agent, and the sprayed liquid will not be discharged from the slag discharge pipe, and the intake pipe is closed. The nozzle and the air outlet pipe are both located at the top of the horizontal electric heater, so a water storage space similar to a cup is formed inside the horizontal electric heater to pre-treat the inside of the horizontal electric heater and soften the dirt. After a period of time, the valve on the slag discharge pipe is opened to allow the liquid to flow out. At this time, the inside of the horizontal electric heater can be directly rinsed through the nozzle, and the cleaning effect is better. When the intake pipe is closed and the valve on the slag discharge pipe is opened, the nozzle can directly spray liquid to rinse the inside of the horizontal electric heater, discharge the dirt from the slag discharge pipe, which is simple and fast, and will not react with the residual ammonia, causing the pipeline or the mixer to be corroded by ammonia water. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0026] Figure 1 It is an overall schematic diagram of the device for starting and stopping denitration.

[0027] Figure 2 It is an overall sectional partial structural schematic diagram of the device for starting and stopping denitration.

[0028] Figure 3 Schematic diagram of the back structure of the closing mechanism of the device applied to denitration during startup and shutdown.

[0029] Figure 4 Schematic diagram of the unfolded structure of the closing mechanism of the device applied to denitration during startup and shutdown.

[0030] Figure 5 For the device applied to denitration during startup and shutdown Figure 4 Enlarged schematic diagram of position A. Detailed implementation manners

[0031] In order to make the above objects, features and advantages of the present invention more obvious and understandable, the following detailed description of the specific implementation manners of the present invention will be given in conjunction with the accompanying drawings of the specification.

[0032] In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention may be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0033] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure or characteristic that may be included in at least one implementation manner of the present invention. The appearances of "in one embodiment" in different places in this specification do not all refer to the same embodiment, nor are they separate or alternative embodiments that are mutually exclusive of other embodiments.

[0034] Embodiment 1, referring to Figures 1 to 5, which is the first embodiment of the present invention. This embodiment provides a device for denitrification during startup and shutdown, which includes a horizontal electric heater 100, on which an intake pipe 101, an outlet pipe 102, and a slag discharge pipe 103 are provided and communicate with the inner cavity of the horizontal electric heater 100. The intake pipe 101 is located at one end of the horizontal electric heater 100, the outlet pipe 102 is located at the top of the horizontal electric heater 100, and the slag discharge pipe 103 is located at the bottom of the horizontal electric heater 100. A valve is provided on the slag discharge pipe 103. It also includes a spray head 104 provided on the side wall of the inner cavity of the horizontal electric heater 100 and located above the intake pipe 101. The spray head 104 is selected as a high-pressure spray head 104 with adjustable angle, and the spray head 104 is connected with a pipeline. Liquid is sprayed out from the spray head 104 through the pipeline to clean the inside of the horizontal electric heater 100. A closing mechanism 200 for shielding the spray head 104 or the intake pipe 101 is provided on the inner wall of the horizontal electric heater 100. The closing mechanism 200 includes a shielding portion 201 provided in the inner cavity of the horizontal electric heater 100, a driving component 202 for driving the shielding portion 201 to move, and a lifting component 203 for assisting the driving component 202 to drive the shielding portion 201 to move. When the horizontal electric heater 100 needs to be used, the shielding portion 201 is driven by the cooperation of the driving component 202 and the lifting component 203 to close the spray head 104, so that impurities in the gas will not adhere to the water outlet holes of the spray head 104, causing the water outlet holes to be blocked. When the horizontal electric heater 100 needs to be internally cleaned, the intake pipe 101 is shielded by the cooperation of the driving component 202 and the lifting component 203, avoiding water entering the flue gas / ammonia mixer from the intake pipe 101 during the cleaning process and reacting with the residual ammonia in the flue gas / ammonia mixer and the pipeline to generate ammonia water. Ammonia water is corrosive and will corrode the pipeline or the mixer, thus affecting the use of the equipment. When the intake pipe 101 is closed and the valve on the slag discharge pipe 103 is closed, at this time, the water sprayed out by the spray head 104 can be mixed with a cleaning agent. The sprayed liquid will not be discharged from the slag discharge pipe 103, and the intake pipe 101 is closed. Both the spray head 104 and the outlet pipe 102 are located at the top of the horizontal electric heater 100. Therefore, a water storage space similar to a cup is formed inside the horizontal electric heater 100 to pre-treat the inside of the horizontal electric heater 100 and soften the dirt. After a period of time, the valve on the slag discharge pipe 103 is opened to allow the liquid to flow out. At this time, the inside of the horizontal electric heater 100 can be directly rinsed through the spray head 104, and the cleaning effect is better. When the intake pipe 101 is closed and the valve on the slag discharge pipe 103 is opened, the spray head 104 can directly spray liquid to rinse the inside of the horizontal electric heater 100, discharging the dirt from the slag discharge pipe 103, which is simple and fast and will not react with the residual ammonia, causing the pipeline or the mixer to be corroded by ammonia water.

[0035] Further, the driving component 202 includes a driving motor 202a disposed on the horizontal electric heater 100. The output end of the driving motor 202a extends into the inner cavity of the horizontal electric heater 100 and is connected to a disc 202b. A driving rod 202c is fixedly connected to the side of the disc 202b away from the driving motor 202a. The driving rod 202c is close to the edge of the disc 202b. By starting the driving motor 202a, the driving motor 202a drives the disc 202b to rotate, and the disc 202b drives the driving rod 202c to rotate. When the driving rod 202c is at the highest position, the driving rod 202c drives the shielding part 201 to shield the nozzle 104 through the lifting component 203. When the driving rod 202c is at the lowest position, the driving rod 202c drives the lifting component 203 to shield the air inlet pipe 101.

[0036] Further, the lifting component 203 includes a bearing block 203a disposed on the side of the disc 202b away from the driving motor 202a. A first sliding groove 203b is formed in the bearing block 203a, and the bearing block 203a is connected to the shielding part 201 through a vertical plate 203c. It also includes two side plates 203d installed in the inner cavity of the horizontal electric heater 100. The end of the driving rod 202c away from the disc 202b slides through the first sliding groove 203b. The first sliding groove 203b matches the rotation trajectory of the driving rod 202c. The shielding part 201 is located between the two side plates 203d. When the disc 202b drives the driving rod 202c to rotate, when the driving rod 202c rotates from the bottommost to the topmost, the driving rod 202c slides inside the first sliding groove 203b. At the same time, the driving rod 202c drives the bearing block 203a to move upward. The two side plates 203d limit the moving trajectory of the bearing block 203a, so that the shielding part 201 can accurately align with the nozzle 104 and the nozzle of the air inlet pipe 101. When the bearing block 203a moves upward, it drives the shielding part 201 to move upward through the vertical plate 203c and shield the nozzle of the nozzle 104. On the contrary, when the driving rod 202c rotates from the topmost to the bottommost, the driving rod 202c drives the shielding part 201 to shield the nozzle of the air inlet pipe 101 through the bearing block 203a and the vertical plate 203c.

[0037] Further, the bearing block 203a is rectangular, and the two ends of the bearing block 203a away from each other are respectively attached to the sides of the two side plates 203d close to each other. By setting the bearing block 203a to be rectangular and the two ends are respectively attached to the sides of the two side plates 203d close to each other, the bearing block 203a is limited. Further, in cooperation with the two side plates 203d, the bearing block 203a will not rotate, so as not to affect the driving rod 202c driving the shielding part 201 to move through the bearing block 203a.

[0038] In this embodiment, the shielding part 201 can be a rectangular plate. During use, by turning on the drive motor 202a, the drive motor 202a drives the disc 202b to rotate, and the disc 202b drives the drive rod 202c to rotate. As the drive rod 202c rotates from the lowest position to the highest position and from the highest position to the lowest position, the drive rod 202c drives the shielding part 201 to move upward or downward through the first chute 203b, the bearing block 203a, and the vertical plate 203c, so that the shielding plate shields the nozzle 104 or the nozzle of the intake pipe 101. When the drive motor 202a is turned on, only setting it to rotate 90 degrees can realize the switching of shielding between the nozzle 104 and the nozzle of the intake pipe 101, without considering forward or reverse rotation.

[0039] Embodiment 2, referring to Figures 2 to 5 , which is the second embodiment of the present invention. Different from the previous embodiment, in this embodiment, a second chute 203d-1 and a third chute 203d-2 are provided on one side of the side plate 203d close to the bearing block 203a. The second chute 203d-1 communicates with the third chute 203d-2. The second chute 203d-1 is inclined. A slide bar 203d-3 is slidably arranged inside the second chute 203d-1. One end of the slide bar 203d-3 passes through the second chute 203d-1 and is connected to the shielding part 201. The second chute 203d-1, the third chute 203d-2, and the movement track of the slide bar 203d-3 match. Through the inclined second chute 203d-1, when the shielding part 201 moves upward, the slide bar 203d-3 enters the second chute 203d-1 from the third chute 203d-2 and moves inside the second chute 203d-1, the shielding part 201 moves obliquely, and the shielding part 201 approaches the nozzle 104. When the shielding part 201 moves to the maximum height, the shielding part 201 fits with the end of the nozzle 104 to shield the end of the nozzle 104. During the movement, the shielding part 201 does not contact the side of the nozzle 104 close to the shielding plate, avoiding wear.

[0040] Furthermore, the shielding part 201 includes a first shielding plate 201a and a second shielding plate 201b. A cross plate 201c is connected to the first shielding plate 201a. One end of the slide bar 203d-3 passes through the second chute 203d-1 and is connected to the cross plate 201c. The first shielding plate 201a and the second shielding plate 201b are connected by an adjusting component 201d. The second shielding plate 201b is L-shaped and is connected to the end of the vertical plate 203c away from the bearing block 203a. The setting of the adjusting component 201d enables the second shielding plate 201b to better fit with the nozzle of the intake pipe 101.

[0041] Furthermore, the sides of the first baffle 201a and the second baffle 201b away from the disk 202b are flush with the sides of the side plate 203d away from the inner wall of the horizontal electric heater 100, and the sides of the first baffle 201a and the second baffle 201b away from each other are respectively in contact with the two side plates 203d. This setting makes it so that when the nozzle 104 is blocked, the first baffle 201a, the L-shaped second baffle 201b, the two side plates 203d, and the cross plate 201c form a rectangular space. This space allows the disk 202b, the carrier, etc. to be wrapped when the device is not in use, forming an enclosed space to prevent dirt from adhering, especially to the inner wall of the first chute 203b, thus affecting the use of the device. Also, it can make the first baffle 201a and the second baffle 201b block the second chute 203d-1 and the third chute 203d-2 to prevent affecting the movement of the first baffle 201a and the second baffle 201b.

[0042] All other structures are the same as those in Embodiment 1.

[0043] During use, the slide bar 203d-3 moves along the third chute 203d-2 into the second chute 203d-1. Due to the inclined second chute 203d-1, the slide bar 203d-3 drives the first baffle 201a to move upward and approach the nozzle 104 through the cross plate 201c, achieving the blocking of the nozzle 104. At this time, the sides of the first baffle 201a and the second baffle 201b away from the disk 202b are flush with the sides of the side plate 203d away from the inner wall of the horizontal electric heater 100, and the sides of the first baffle 201a and the second baffle 201b away from each other are respectively in contact with the two side plates 203d, making the first baffle 201a, the L-shaped second baffle 201b, the two side plates 203d, and the cross plate 201c form a rectangular space. This space allows the disk 202b, the carrier, etc. to be wrapped when the device is not in use, forming an enclosed space to prevent dirt from adhering, especially to the first chute 203b, the second chute 203d-1, and the third chute 203d-2, to prevent affecting the use of the device.

[0044] Embodiment 3, refer to Figures 2 to 5, which is the third embodiment of the present invention. Different from the previous embodiment, in this embodiment, the adjusting assembly 201d includes a first inclined surface 201d-1 provided at the bottom of the second baffle 201b, a diversion block 201d-2 installed on the inner wall of the horizontal electric heater 100, a second inclined surface 201d-3 provided on the diversion block 201d-2, and further includes a telescopic rod 201d-4 connected to the first baffle 201a, and a spring 201d-5 sleeved on the surface of the telescopic rod 201d-4. One ends of the telescopic rod 201d-4 and the spring 201d-5 far from the first baffle 201a are both connected to the second baffle 201b through a folding plate 201d-6. When the sliding rod 203d-3 moves from the second chute 203d-1 to the inside of the third chute 203d-2, the sliding rod 203d-3 drives the second baffle 201b to be misaligned with the nozzle of the intake pipe 101 through the cross plate 201c, the first baffle 201a and the adjusting assembly 201d. When the second baffle 201b descends along the trajectory of the third chute 203d-2 and the first inclined surface 201d-1 at the bottom of the second baffle 201b contacts the second inclined surface 201d-3 on the diversion block 201d-2, the second baffle 201b moves closer to the nozzle of the intake pipe 101. The second baffle 201b drives the telescopic rod 201d-4 and the spring 201d-5 to stretch through the folding plate 201d-6. The telescopic rod 201d-4 ensures the connection between the first baffle 201a and the second baffle 201b. When the second baffle 201b moves to the lowest position, the second baffle 201b fits with the nozzle of the intake pipe 101, realizing the closing of the intake pipe 101, avoiding water from entering the flue gas / ammonia mixer through the intake pipe 101 during the cleaning process, reacting with the residual ammonia in the flue gas / ammonia mixer and the pipeline to generate ammonia water. Ammonia water is corrosive and can corrode the pipeline or the mixer, thus affecting the use of the equipment. When the second baffle 201b moves upward, the spring 201d-5 automatically drives the second baffle 201b to reset through the folding plate 201d-6.

[0045] Further, an arc surface is provided at the end of one end of the intake pipe 101 located in the horizontal electric heater 100, and the arc surface corresponds to the second chute 203d-1. The setting of the arc surface enables the second baffle 201b to move along the arc surface when the sliding rod 203d-3 enters the inside of the second chute 203d-1 from the third chute 203d-2 and drives the first baffle 201a and the second baffle 201b to move obliquely upward, reducing the installation space of the device and thus reducing the cost.

[0046] The remaining structures are the same as those in Embodiment 2.

[0047] During use, the slide bar 203d-3 moves from the second chute 203d-1 to the third chute 203d-2. First, the slide bar 203d-3 drives the second shielding part 201 to be misaligned with the pipe orifice of the intake pipe 101 through the cross plate 201c, the first shielding plate 201a, and the adjusting component 201d. When the first inclined surface 201d-1 at the bottom of the second shielding plate 201b contacts the second inclined surface 201d-3 on the diversion block 201d-2, the second shielding plate 201b moves closer to the pipe orifice of the intake pipe 101, causing the second shielding plate 201b to fit against the pipe orifice of the intake pipe 101, thereby closing the intake pipe 101. This prevents water from entering the flue gas / ammonia mixer through the intake pipe 101 during the cleaning process and reacting with the ammonia remaining in the flue gas / ammonia mixer and the pipeline to form ammonia water. Ammonia water is corrosive and can corrode the pipeline or mixer, thus affecting the use of the equipment.

[0048] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A device applied to denitration during startup and shutdown, characterized in that: including, a horizontal electric heater (100) provided with an intake pipe (101), an outlet pipe (102) and a slag discharge pipe (103) communicating with the inner cavity of the horizontal electric heater (100). The intake pipe (101) is located at one end of the horizontal electric heater (100), the outlet pipe (102) is located at the top of the horizontal electric heater (100), the slag discharge pipe (103) is located at the bottom of the horizontal electric heater (100), and further includes a spray head (104) provided on the side wall of the inner cavity of the horizontal electric heater (100) and located above the intake pipe (101); wherein, a valve is provided on the slag discharge pipe (103); a closing mechanism (200), which includes a shielding part (201) provided in the inner cavity of the horizontal electric heater (100), a driving component (202) for driving the shielding part (201) to move, and a lifting component (203) for assisting the driving component (202) to drive the shielding part (201) to move; the driving component (202) includes a driving motor (202a) provided on the horizontal electric heater (100). The output end of the driving motor (202a) extends into the inner cavity of the horizontal electric heater (100) and is connected with a disc (202b), and a driving rod (202c) is connected to the side of the disc (202b) away from the driving motor (202a); the driving rod (202c) is close to the edge of the disc (202b); the lifting component (203) includes a bearing block (203a) provided on the side of the disc (202b) away from the driving motor (202a). A first sliding groove (203b) is formed in the bearing block (203a), and the bearing block (203a) is connected with the shielding part (201) through a vertical plate (203c). It also includes two side plates (203d) installed in the inner cavity of the horizontal electric heater (100); one end of the driving rod (202c) away from the disc (202b) slides through the first sliding groove (203b); the shielding part (201) is located between the two side plates (203d); the bearing block (203a) is rectangular, and the two ends of the bearing block (203a) away from each other are respectively attached to the sides of the two side plates (203d) close to each other; a second sliding groove (203d-1) and a third sliding groove (203d-2) are formed on the side of the side plate (203d) close to the bearing block (203a). The second sliding groove (203d-1) communicates with the third sliding groove (203d-2). The second sliding groove (203d-1) is inclined. A sliding rod (203d-3) is slidably arranged in the second sliding groove (203d-1). One end of the sliding rod (203d-3) passes out of the second sliding groove (203d-1) and is connected with the shielding part (201). The second sliding groove (203d-1), the third sliding groove (203d-2) and the moving track of the sliding rod (203d-3) are matched; The shielding part (201) includes a first shielding plate (201a) and a second shielding plate (201b). A cross plate (201c) is connected to the first shielding plate (201a), and the first shielding plate (201a) and the second shielding plate (201b) are connected by an adjusting component (201d). The second shielding plate (201b) is L-shaped and is connected to the end of the vertical plate (203c) away from the bearing block (203a). On the side of the first shielding plate (201a) and the second shielding plate (201b) away from the disc (202b), they are flush with the side of the side plate (203d) away from the inner wall of the horizontal electric heater (100), and the sides of the first shielding plate (201a) and the second shielding plate (201b) away from each other are respectively attached to the two side plates (203d).

2. The device for startup and shutdown denitration according to claim 1, characterized in that: The adjusting component (201d) includes a first inclined surface (201d-1) provided at the bottom of the second shielding plate (201b), a diversion block (201d-2) installed on the inner wall of the horizontal electric heater (100), and a second inclined surface (201d-3) provided on the diversion block (201d-2).

3. The device for start-up and shutdown denitration according to claim 2, characterized in that: The adjusting component (201d) further includes a telescopic rod (201d-4) connected to the first shielding plate (201a), a spring (201d-5) sleeved on the surface of the telescopic rod (201d-4). The ends of the telescopic rod (201d-4) and the spring (201d-5) away from the first shielding plate (201a) are both connected to the second shielding plate (201b) through a folding plate (201d-6).

4. The device for startup and shutdown denitration according to claim 3, characterized in that: The end of the air inlet pipe (101) at one end of the horizontal electric heater (100) is provided with an arc surface, and the arc surface corresponds to the second chute (203d-1).

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