SCR denitration device

Abstract

The utility model discloses a kind of SCR denitration devices, belong to solve the problem of scratch to catalyst in the process of ash removal, solve the problem of scratch to catalyst in the process of ash removal, the technical scheme of solving this problem mainly includes rotary kiln, preheater, ammonia injection system and SCR reaction tower, preheater is located above rotary kiln, SCR reaction tower is equipped with flue gas pipeline between preheater, SCR reaction tower is equipped with mounting bracket, SCR reaction tower outside is equipped with fixing frame, mounting bracket is equipped with ash removal pipe, ash removal pipe is equipped with ash removal harrow, ash removal harrow is equipped with nozzle, fixing frame is equipped with feeding mechanism and air blower, one end of ash removal pipe extends to SCR reaction tower outside and is connected with feeding mechanism, feeding mechanism drives ash removal harrow reciprocating motion by ash removal pipe, ash removal pipe is equipped with anti-blocking fan to prevent nozzle from entering dust and being blocked during ash removal harrow retraction process.The utility model mainly guarantees ash removal effect while reducing damage to catalyst, and then ensure denitration effect.

Description

Technical Field

[0001] This utility model relates to the technical field of flue gas denitrification, and in particular to an SCR denitrification device. Background Technology

[0002] SCR (Selective Catalytic Reduction) is currently the most widely used flue gas denitrification technology internationally. It involves injecting ammonia into flue gas at a temperature of approximately 280-420°C under the action of a catalyst, reducing nitrogen oxides into nitrogen and water, thereby reducing nitrogen oxide emissions.

[0003] Existing technology CN202110420352.2 discloses an SCR denitrification dust removal device, including a catalyst assembly composed of several neatly arranged catalyst bodies; a scraper disposed above the catalyst assembly; and a driving device disposed on one side of the catalyst assembly, connected to the scraper, for driving the scraper to move above the catalyst assembly. The scraper can contact the dust accumulated on the upper surface of the catalyst assembly, and driven by the driving device, the scraper reciprocates above the catalyst assembly, thereby scraping away some of the dust accumulated on the upper surface of the catalyst assembly, reducing the thickness of the accumulated dust, preventing dust from accumulating on the catalyst assembly and affecting its activity, thoroughly removing the accumulated dust, increasing the service life of the catalyst assembly, and improving the dust removal effect.

[0004] In the aforementioned prior art, although the dust accumulated on the catalyst surface can be removed by scraping with a scraper, the reciprocating scraping motion of the scraper can also scratch the catalyst. With long-term dust removal and scraping, the catalyst may be severely damaged, thereby reducing the denitrification effect. Utility Model Content

[0005] The purpose of this invention is to provide an SCR denitrification device that solves the problem of scratching the catalyst during the cleaning process, ensuring the cleaning effect while reducing damage to the catalyst, thereby ensuring the denitrification effect.

[0006] To achieve the above objectives, this utility model adopts the following technical solution: an SCR denitrification device, comprising a rotary kiln, a preheater, an ammonia injection system, and an SCR reaction tower. The preheater is located above the rotary kiln, and the flue gas from the rotary kiln enters the preheater. A flue gas duct is provided between the SCR reaction tower and the preheater. The ammonia injection system injects ammonia into the flue gas so that the ammonia enters the flue gas duct with the flue gas. The flue gas generated in the rotary kiln enters the flue gas duct from the top of the preheater and then enters the SCR reaction tower for denitrification. The SCR reaction tower contains... An installation frame is provided, and a fixed frame is provided on the outside of the SCR reaction tower. A cleaning pipe is provided on the installation frame, and a cleaning rake is provided on the cleaning pipe. The cleaning rake is provided with nozzles facing the catalyst. A feeding mechanism and a blower connected to the cleaning pipe are provided on the fixed frame. One end of the cleaning pipe extends to the outside of the SCR reaction tower and is connected to the feeding mechanism. The feeding mechanism drives the cleaning rake to reciprocate through the cleaning pipe. An anti-clogging fan is provided on the cleaning pipe. The anti-clogging fan blows air into the cleaning pipe during the retraction of the cleaning rake to prevent dust from entering the nozzles and causing blockage.

[0007] After adopting the above technical solution, this utility model has the following advantages: While producing corresponding products under the high temperature of the ore raw material in the rotary kiln, high-temperature flue gas is also generated. This high-temperature flue gas enters the flue gas channel of the preheater, where it undergoes heat transfer with the ore entering the rotary kiln from the preheater, preheating the ore and ensuring that it can fully react after entering the rotary kiln. While the ore is preheated, the temperature of the flue gas gradually decreases, reaching approximately 300 to 350°C in the flue gas entering the pipe. The ammonia injection system injects ammonia into the flue gas at the flue gas inlet pipe, allowing the ammonia to mix with the flue gas. As the flue gas flows along the flue gas pipe, the ammonia and flue gas mix more evenly, ensuring the denitrification effect of the flue gas. Since the ore-based flue gas contains a lot of dust, when the flue gas enters the SCR reaction tower and comes into contact with the catalyst, the dust will adhere to the catalyst surface. The adhered dust will affect the full contact between the flue gas and the catalyst, thus affecting the denitrification effect of the flue gas. By setting up mounting brackets and fixing brackets on the SCR reaction tower… The system includes corresponding cleaning pipes, cleaning rakes, nozzles, feeding mechanisms, and fan structures. The mounting and fixing frames ensure the stability of the cleaning pipes and feeding mechanism. The feeding mechanism drives the cleaning rake, reducing its volume and weight to ensure stability during reciprocating motion. This also reduces the rake's obstruction of flue gas and decreases the ash accumulation area within the SCR reactor. During cleaning, the fan blows gas into the cleaning pipe, which then exits through the nozzles. The blown gas acts on the catalyst surface, causing dust to rise and flow with the flue gas, reducing dust adhering to the catalyst and ensuring sufficient contact between the flue gas and the catalyst, thus guaranteeing the denitrification effect. Compared to the scraper in the existing technology CN202110420352.2, cleaning with gas through nozzles avoids direct contact with the catalyst, reducing damage during cleaning and further ensuring the catalyst's catalytic effect, thereby guaranteeing the denitrification effect of the flue gas.

[0008] Furthermore, the cleaning pipe includes an inner cleaning pipe and an outer cleaning pipe. The inner cleaning pipe is mounted on a fixed frame. One end of the outer cleaning pipe is sleeved on the inner cleaning pipe, and the other end extends into the SCR reaction tower. The cleaning rake is connected to and communicates with the outer cleaning pipe. The feeding mechanism is connected to the outer cleaning pipe to drive the outer cleaning pipe to reciprocate relative to the inner cleaning pipe.

[0009] Using the aforementioned technical solution, the cleaning pipe is configured as an inner and outer pipe. A feeding mechanism drives the outer cleaning pipe to move, ensuring its reciprocating movement during the cleaning process. This, in turn, drives the cleaning rake to reciprocate for cleaning.

[0010] Furthermore, the outer cleaning pipe is equipped with a sealing element, which is sealed to the SCR reaction tower.

[0011] By adopting the aforementioned technical solution, the external cleaning pipe and the SCR reaction tower are sealed together by a sealing component, reducing the possibility of dust overflowing from the connection between the external cleaning pipe and the SCR reaction tower.

[0012] Furthermore, the mounting frame includes a mounting beam and a suspension frame. The length direction of the mounting beam is consistent with the length direction of the cleaning pipe. One end of the suspension frame is slidably connected to the mounting beam, and the other end is connected to the cleaning pipe.

[0013] By adopting the aforementioned technical solution, the mounting frame is set up in the form of a mounting beam and a suspension frame. The mounting beam ensures the stability of the ash removal pipe, and the upper end of the suspension frame is slidably connected to the mounting beam to ensure that the ash removal pipe can reciprocate to remove ash.

[0014] Furthermore, the cleaning rake is provided in multiple parts, and the multiple cleaning rakes are distributed at equal intervals along the length direction of the cleaning outer tube.

[0015] By adopting the aforementioned technical solution, multiple cleaning rakes are set at equal intervals to reduce the reciprocating motion of the cleaning rakes, thereby ensuring the stability of the cleaning process.

[0016] Furthermore, the SCR reaction tower has multiple layers of catalyst, one of which serves as a backup layer. A heating element is located below the catalyst to heat the catalyst above, and a cleaning rake is located above the catalyst.

[0017] By adopting the aforementioned technical solution, multiple layers of catalyst are set up. Through contact between the flue gas and the multiple layers of catalyst, it is ensured that the flue gas and ammonia can react more fully, thereby improving the denitrification effect of the flue gas. One layer of catalyst serves as a backup layer, which is activated after the SCR reaction tower has been used for a long time. This effectively avoids the denitrification effect of the flue gas being affected by the decline in catalytic effect after a long denitrification time.

[0018] Furthermore, the top of the SCR reaction tower is provided with a first flue gas inlet section, one end of the flue gas pipe is connected to the flue gas outlet channel of the preheater, and the other end is connected to the first flue gas inlet section.

[0019] By adopting the aforementioned technical solution, a first flue gas inlet section is set at the top of the SCR reactor, and then the first flue gas inlet section is connected to the flue gas duct, thereby increasing the range of connection between the flue gas duct and the SCR reactor and ensuring that the flue gas can smoothly enter the SCR reactor.

[0020] Furthermore, the first flue gas inlet section is equipped with an expansion joint and a first switching valve.

[0021] By adopting the aforementioned technical solution, the expansion joint reduces the possibility of damage to the SCR reactor caused by the impact of flue gas entering the first flue gas inlet section, ensuring that the flue gas can smoothly enter the SCR reactor. The first switching valve controls the opening and closing of the first flue gas inlet section to ensure the operation and shutdown of the SCR reactor, effectively preventing flue gas from being discharged from the SCR reactor without denitrification.

[0022] Furthermore, it also includes a boiler, and the flue gas pipeline includes a main flue gas pipe, a first flue gas branch pipe and a second flue gas branch pipe. The first flue gas branch pipe is connected to the SCR reactor tower and is equipped with a first switching valve. The second flue gas branch pipe is connected to the boiler's air inlet and is equipped with a second switching valve.

[0023] The aforementioned technical solution also includes a boiler, which is connected to the boiler via a second flue gas branch pipe. This allows for the conversion and utilization of heat in the flue gas, improving energy efficiency and reducing energy consumption. The flow and obstruction of the flue gas are controlled by the first and second switching valves, thereby ensuring the denitrification and heat conversion of the flue gas and reducing the environmental harm caused by direct emissions of flue gas.

[0024] Furthermore, the flue gas branch pipe also includes a third flue gas branch pipe, one end of which is connected to the SCR reaction tower and the other end of which is connected to the second flue gas branch pipe. The connection between the third flue gas branch pipe and the second flue gas branch pipe is located between the second switch valve and the boiler, and the third flue gas branch pipe is equipped with a third switch valve.

[0025] By adopting the aforementioned technical solution, a third flue gas branch pipe is installed between the SCR reaction tower and the boiler, allowing the denitrified flue gas to pass through the boiler. The boiler then converts and utilizes the heat carried in the flue gas, thereby improving the utilization rate of the heat in the flue gas and reducing energy consumption. Attached Figure Description

[0026] The present invention will be further described below with reference to the accompanying drawings:

[0027] Figure 1 This is a schematic diagram of an SCR denitrification device according to the present invention;

[0028] Figure 2 This is a schematic diagram of the installation of the cleaning pipe and the cleaning rake in this utility model;

[0029] Figure 3 This is a schematic diagram of the structure of the cleaning pipe in this utility model;

[0030] Figure 4 This is a schematic diagram of the dust removal rake in this utility model;

[0031] Figure 5 This is a schematic diagram of the mounting bracket in this utility model;

[0032] Figure 6 This is a schematic diagram of the SCR reaction tower in this utility model. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments.

[0034] The terms "first," "second," etc. (if present) in the specification and claims of this utility model are used to distinguish similar objects, not to describe a specific order or sequence. Even if "second" is used before a technical feature for distinction, it does not necessarily imply the presence of "first." It should be understood that in this utility model, "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. It should be understood that in this utility model, "multiple" refers to two or more. "And / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, X and / or Y can represent: X alone, X and Y simultaneously, and Y alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "Containing X, Y, and Z," "Containing X, Y, and Z" means that all three X, Y, and Z are included; "Containing X, Y, or Z" means that one of X, Y, and Z is included; "Containing X, Y, and / or Z" means that any one, two, or three of X, Y, and Z are included.

[0035] The technical solution of this utility model will be described in detail below with specific embodiments. The following specific embodiments can be selected to be combined or substituted with each other according to the actual situation, and the same or similar concepts or processes may not be described again in some embodiments.

[0036] like Figures 1 to 5 As shown, this utility model provides an SCR denitrification device, including a rotary kiln 1, a preheater 2, an ammonia injection system 3, and an SCR reaction tower 4. The preheater 2 is located above the rotary kiln 1, and the flue gas in the rotary kiln 1 enters the preheater 2. A flue gas pipe 6 is provided between the SCR reaction tower 4 and the preheater 2. The ammonia injection system 3 injects ammonia into the flue gas so that the ammonia enters the flue gas pipe 6 with the flue gas. The flue gas formed in the rotary kiln 1 enters the flue gas pipe 6 from the top of the preheater 2 and then enters the SCR reaction tower 4 for denitrification. Figure 2As shown, an installation frame 42 is provided inside the SCR reaction tower 4, and a fixed frame 43 is provided outside the SCR reaction tower 4. A cleaning pipe 421 is provided on the installation frame 42, and a cleaning rake 422 is provided on the cleaning pipe 421. A nozzle 4221 facing the catalyst 41 is provided on the cleaning rake 422. A feeding mechanism 431 and a blower 423 connected to the cleaning pipe 421 are provided on the fixed frame 43. One end of the cleaning pipe 421 extends to the outside of the SCR reaction tower 4 and is connected to the feeding mechanism 431. The feeding mechanism 431 drives the cleaning rake 422 to reciprocate through the cleaning pipe 421. An anti-clogging fan 424 is provided on the cleaning pipe 421. The anti-clogging fan 424 blows air into the cleaning pipe 421 during the retraction of the cleaning rake 422 to prevent dust from entering the nozzle 4221 and causing blockage.

[0037] Specifically, during the flue gas treatment process, the dust-laden flue gas generated by the rotary kiln 1 enters the SCR reaction tower 4 via the preheater 2. The ammonia injection system 3 mixes ammonia into the flue gas, causing a reduction reaction on the surface of the catalyst 41. During the dust removal operation, the blower 423 delivers compressed air to the dust removal pipe 421, and the airflow forms a directional jet through the nozzle 4221 of the dust removal rake 422, impacting the dust accumulated on the surface of the catalyst 41. The feeding mechanism 431 drives the dust removal pipe 421 to reciprocate axially, causing the dust removal rake 422 to perform scanning dust removal on the surface of the catalyst 41. When the dust removal rake 422 retracts, the anti-blocking fan 424 starts to generate a reverse airflow, preventing dust in the flue gas from entering the nozzle 4221. The mounting frame 42 and the fixed frame 43 form an internal and external cooperative support system to ensure the stability of the movement trajectory of the dust removal pipe 421.

[0038] Compared to existing technology CN202110420352.2, which relies on physical contact to remove accumulated dust, this solution uses airflow impact to achieve non-contact cleaning, fundamentally eliminating the risk of catalyst 41 damage. Traditional cleaning mechanisms lack backflow prevention design; this solution establishes a dynamic airflow barrier by adding an anti-clogging fan 424, effectively solving the nozzle 4221 clogging problem. Conventional cleaning equipment uses a single drive mode; this solution achieves automated cleaning operation through the coordinated control of the feeding mechanism 431 and the blower 423. This achieves non-destructive cleaning of the catalyst 41 surface, avoiding damage to the catalyst 41 caused by mechanical scraping. The establishment of the dynamic airflow barrier significantly reduces the probability of nozzle 4221 clogging, extending the continuous operation cycle of the cleaning system. The automated cleaning mechanism improves cleaning efficiency and ensures stable catalyst 41 activity. The internal and external synergistic support structure enhances system operational stability and adapts to harsh working environments with high temperature and high dust.

[0039] In this embodiment, as Figure 2 and Figure 3As shown, the cleaning pipe 421 further includes an inner cleaning pipe 4211 and an outer cleaning pipe 4212. The inner cleaning pipe 4211 is mounted on a fixed frame 43. One end of the outer cleaning pipe 4212 is sleeved on the inner cleaning pipe 4211, and the other end extends into the SCR reaction tower 4. The cleaning rake 422 is connected to and communicates with the outer cleaning pipe 4212. The feeding mechanism 431 is connected to the outer cleaning pipe 4212 to drive the outer cleaning pipe 4212 to reciprocate relative to the inner cleaning pipe 4211.

[0040] The inner cleaning pipe 4211 is a rigid pipe fixed to the external frame, which can be made of stainless steel and welded together. Its interior forms a gas delivery channel, providing a stable support base and gas transmission path for the outer cleaning pipe 4212. The outer cleaning pipe 4212 is an axially sliding movable pipe, which can be made of carbon steel with a wear-resistant coating. It forms a sealed sliding pair with the inner cleaning pipe 4211 through a sleeve connection, used to deliver the cleaning airflow to the cleaning rake 422 and transmit the driving force of the feeding mechanism 431. The sleeve connection refers to the nested fit structure of the inner and outer pipes, which can adopt a stepped shaft fit and be equipped with a polytetrafluoroethylene sealing ring, ensuring airtightness while allowing free expansion and contraction of the outer pipe.

[0041] Specifically, the outer cleaning pipe 4212, driven by the feeding mechanism 431, reciprocates linearly along the axis of the inner cleaning pipe 4211, driving the cleaning rake 422 connected to its end to perform non-contact cleaning operations above the catalyst layer 41. When the outer pipe extends forward, the cleaning rake 422 moves to the predetermined cleaning area, at which point the blower 423 delivers high-pressure gas to the nozzle 4221 through the inner and outer pipe channels for purging; when the outer pipe retracts, the cleaning rake 422 exits the working area, and the anti-clogging blower 424 starts simultaneously to prevent dust from entering the nozzle 4221 and causing blockage. The separate design of the inner and outer pipes allows the movement trajectory of the cleaning rake 422 to be completely controlled by the displacement of the outer pipe, avoiding contact friction between the traditional rigid connection mechanism and the surface of the catalyst 41. Compared to the existing technology CN202110420352.2, the existing dust removal device adopts a direct contact scraper structure, which inevitably causes mechanical scraping with the catalyst 41 during reciprocating motion. This solution, however, uses an inner and outer tube sleeve drive method to maintain a constant gap between the dust removal rake 422 and the catalyst 41, achieving contactless dust removal through gas impact. The existing scraper movement mechanism requires a complex guiding device to prevent deviation, while this solution naturally forms axial movement constraint through the cooperation of the fixed inner tube and the movable outer tube, significantly simplifying the mechanical structure. This effectively eliminates physical contact between the moving parts of the dust removal device and the surface of the catalyst 41, avoiding surface scratches caused by scraper-type dust removal tools. The split structure of the inner and outer tubes ensures stable airflow delivery for dust removal while achieving precise positioning control of the dust removal rake 422, ensuring that the dust removal process does not generate any mechanical stress on the catalyst 41 layer, thereby maintaining the integrity and denitrification activity of the catalyst 41. The sleeve connection between the movable outer tube and the fixed inner tube further improves the motion stability of the dust removal system and prevents the dust removal rake 422 from lateral displacement during high-speed reciprocating motion, which could lead to accidental collisions.

[0042] In this embodiment, as Figure 2 As shown, a sealing element 44 is further proposed to be installed on the ash removal outer pipe 4212, and the sealing element 44 is sealed to the SCR reaction tower 4.

[0043] The sealing element 44 refers to a flexible or elastic structure used to seal the gap between the external cleaning pipe 4212 and the reaction tower. Specifically, it can be implemented using a bellows or an elastic sealing ring. The bellows adapts to the reciprocating motion of the external cleaning pipe 4212 through axial expansion and contraction, while the elastic sealing ring fills the gap through compression deformation. The sealing connection refers to achieving a gapless contact between the sealing element 44 and the inner wall of the reaction tower through mechanical clamping or elastic deformation. Specifically, it can be achieved using flange clamping or clamp locking. Flange clamping uses bolts to fix the sealing element 44 to the reaction tower wall, while clamp locking uses an annular clamp to radially compress the sealing element 44.

[0044] Specifically, when the cleaning outer pipe 4212 reciprocates under the drive of the feeding mechanism 431, the sealing element 44 moves synchronously with the cleaning outer pipe 4212, maintaining a dynamic seal through the expansion and contraction of the bellows or the deformation of the elastic sealing ring. During the retraction phase of the cleaning rake 422, the sealing element 44 prevents external dust from entering the reaction tower through the gap between the cleaning outer pipe 4212 and the reaction tower, avoiding dust accumulation at the nozzle 4221 and causing blockage. During the forward phase of the cleaning rake 422, the sealing element 44 prevents the leakage of ammonia-containing flue gas from the reaction tower, maintaining the gas concentration required for the denitrification reaction. Because the sealing element 44 always remains in contact with the inner wall of the reaction tower, it effectively isolates the internal and external environments even when the cleaning outer pipe 4212 is in motion. This effectively prevents external dust from entering the reaction tower during the cleaning process and causing nozzle 4221 blockage, while also avoiding a decrease in denitrification efficiency due to ammonia leakage from the reaction tower, ensuring the sealing reliability of the SCR reaction tower 4 during the cleaning operation.

[0045] In another embodiment, such as Figure 5 As shown, the mounting frame 42 further includes a mounting beam 425 and a suspension frame 426. The length direction of the mounting beam 425 is consistent with the length direction of the cleaning pipe 421. One end of the suspension frame 426 is slidably connected to the mounting beam 425, and the other end is connected to the cleaning pipe 421.

[0046] The mounting beam 425 refers to the support structure extending along the length of the cleaning pipe 421, which can be implemented using I-beams or H-beams. Its function is to provide a straight guiding reference for the cleaning pipe 421. The suspension bracket 426 is the transition component connecting the mounting beam 425 and the cleaning pipe 421, which can be implemented using a U-shaped bracket with rollers. Its function is to suspend the cleaning pipe 421 below the mounting beam 425 and allow it to slide along its length. The sliding connection refers to the relative movable fit between the suspension bracket 426 and the mounting beam 425, which can be implemented using a roller and guide rail fit structure. Its function is to reduce the frictional resistance when the cleaning pipe 421 moves.

[0047] Specifically, the mounting beam 425 and the cleaning pipe 421 are arranged parallel to each other, ensuring that the movement trajectory of the cleaning rake 422 completely coincides with the extension direction of the mounting beam 425. The suspension frame 426 forms a sliding pair with the guide rail of the mounting beam 425 via a roller assembly, and is also fixedly connected to the cleaning pipe 421 via a rigid connecting rod. When the feeding mechanism 431 drives the cleaning pipe 421 to reciprocate, the rollers of the suspension frame 426 roll along the mounting beam 425, constraining the cleaning pipe 421 to move only along a single axis, preventing lateral deviation or torsion. The double-end constraint structure of the suspension frame 426 restricts the degree of freedom of movement of the cleaning pipe 421 to linear movement along the direction of the mounting beam 425, avoiding trajectory deviation caused by vibration or airflow disturbance.

[0048] In another embodiment, such as Figure 2 As shown, there are multiple cleaning rakes 422, which are distributed at equal intervals along the length of the cleaning outer tube 4212.

[0049] The multiple cleaning rakes 422 refer to multiple independent cleaning units installed on the cleaning outer pipe 4212. Each cleaning unit achieves cleaning by spraying airflow or vibration onto the surface of the catalyst 41 through nozzles 4221. Specifically, this can be achieved by welding, bolting, or snap-fit ​​connection. The evenly spaced distribution means that the interval between each cleaning rake 422 is consistent. This can be achieved by pre-setting installation points or using a positioning device with scale markings. For example, the spacing can be 200 mm to 500 mm.

[0050] Multiple cleaning rakes 422 divide the cleaning area into several equal sections, with each rake 422 responsible for cleaning a specific section. Driven by the cleaning outer pipe 4212, each cleaning rake 422 moves synchronously along the axial direction, removing dust from the surface of the catalyst 41 through the airflow or vibration released by the nozzle 4221. Since the working range of each cleaning rake 422 is relatively fixed, it only needs to cover its corresponding section during the cleaning process, avoiding mechanical damage caused by repeated scraping of the same area by a single scraper. At the same time, the evenly spaced distribution ensures that the cleaning area is covered without gaps, eliminating blind spots in the cleaning process, and reducing the contact pressure of a single cleaning rake 422 on the catalyst 41 by dispersing the cleaning force.

[0051] In another embodiment, the SCR reaction tower 4 has multiple catalysts 41, one of which is a backup layer, specifically the uppermost catalyst layer 41. A heating element 411 for heating the upper catalyst 41 is provided below the catalyst 41, and a dust removal rake 422 is located above the catalyst 41.

[0052] The multi-layer catalyst 41 refers to at least two parallel layers of catalyst 41, which can be stacked in a honeycomb or plate structure. The standby layer refers to the catalyst 41 layer in a non-working state. The standby layer can be activated by controlling the flue gas flow path via valves. When the working layer experiences a decrease in activity or damage, the standby layer can immediately take over operation. The heating element 411 is a device capable of generating heat, specifically an electric heating tube or steam coil, installed in the support structure below the catalyst 41 layer, regulating the temperature of the catalyst 41 through heat conduction. The cleaning rake 422 being located above the catalyst 41 means that the nozzle 4221 of the cleaning rake 422 maintains a vertical distance from the surface of the catalyst 41. This can be achieved by adjusting the height of the mounting bracket 42, ensuring that the blowing airflow only acts on the deposits on the surface of the catalyst 41.

[0053] Specifically, when multiple catalyst layers 41 are installed in the SCR reaction tower 4, the standby layer is in a standby state. When the activity of the working layer decreases due to cleaning operations or long-term use, the standby layer is put into operation by switching the flue gas channel to maintain the denitrification efficiency. The heating element 411 is arranged below the catalyst layer 41 and heats the catalyst 41 through thermal radiation or thermal conduction, causing the ammonium bisulfate or fly ash clumps attached to the surface to expand and fall off due to heat, reducing the intensity of mechanical cleaning. The cleaning rake 422 is fixed at a specific height above the catalyst layer 41. Compressed air generated by the blower 423 is directionally sprayed through the nozzle 4221, causing the loosened dust to be discharged with the airflow, avoiding direct contact between the cleaning rake 422 and the catalyst layer 41.

[0054] During the dust removal process, wear on the surface of catalyst 41 caused by physical contact is avoided, ensuring the continuous operation of the denitrification system. At the same time, the efficiency of dust removal is improved through thermal action, reducing the airflow pressure and frequency required for jet cleaning.

[0055] In another embodiment, such as Figure 6 As shown, the top of the SCR reaction tower 4 is provided with a first flue gas inlet section 45, and one end of the flue gas pipe 6 is connected to the flue gas outlet channel of the preheater 2, and the other end is connected to the first flue gas inlet section 45.

[0056] The first flue gas inlet section 45 refers to the gas introduction structure located at the top of the reaction tower, which can be implemented using a tapered, gradually expanding channel with its cross-sectional area gradually increasing along the flue gas flow direction. This structure guides the flue gas into a laminar flow state, allowing dust particles to settle naturally under gravity. The flue gas duct 6 refers to the gas conveying component connecting the preheater 2 and the reaction tower, and can be implemented using a metal duct with an insulation layer. The inner wall of the duct can be lined with a wear-resistant ceramic layer to withstand high-speed dust erosion. This duct achieves a bottom-up conveying path for the flue gas through a vertical arrangement.

[0057] Specifically, the flue gas treated by preheater 2 is conveyed upwards through vertically arranged flue gas ducts 6, and its velocity is reduced through the gradually expanding structure of the first flue gas inlet section 45. After entering the reaction tower in a near-laminar state, the flue gas forms a downward flow direction under the action of gravity. This change in flow direction allows dust particles in the flue gas to complete preliminary settling before contacting the catalyst layer 41, with some particles falling directly into the ash hopper at the bottom of the reaction tower. The directional optimization of the flue gas flow path reduces the eddy phenomenon generated by lateral air intake and avoids the direct impact of high-speed airflow on the surface of catalyst 41. It achieves coordinated control of flue gas flow path and dust settling, reducing the need for dust removal on the surface of catalyst 41 by more than 50% while ensuring denitrification efficiency. The establishment of the laminar flow state of the flue gas reduces the amount of dust adhering to the surface of catalyst 41 by about 40%, while avoiding the local wear problem of catalyst 41 caused by the traditional lateral air intake method.

[0058] In this embodiment, an expansion joint and a first switching valve 621 are provided at the first flue gas inlet section 45 at the top of the SCR reaction tower 4.

[0059] The expansion joint refers to a flexible connecting component that can absorb the thermal expansion and deformation of the pipeline. It can be made of metal bellows or rubber, and the elastic deformation of the corrugated structure compensates for the expansion and contraction of the pipeline caused by changes in flue gas temperature. The first switching valve 621 is a shut-off device used to control the flow of flue gas. It can be a butterfly valve or gate valve, and the opening and closing of the flue gas pipeline 6 is adjusted by rotating or raising the valve plate.

[0060] Specifically, during the operation of SCR reactor 4, flue gas temperature fluctuations cause thermal expansion and contraction deformation of the metal pipe in the first flue gas inlet section 45. The expansion joint, through its own corrugated structure, axially compresses or stretches to offset the stress generated by the temperature difference in the pipe, preventing leakage or cracking at the flange connection. The first switching valve 621 is installed downstream of the expansion joint. When it is necessary to cut off the flue gas supply, the valve plate is driven to the closed position to prevent flue gas from entering SCR reactor 4; during normal operation, the valve plate remains open, and the flue gas flow is controlled by adjusting the opening degree. The combined installation of the expansion joint and the first switching valve 621 integrates pipe deformation compensation and flow control functions within a single section. By adding the expansion joint and the switching valve, while maintaining the original ash cleaning function, the stability of the pipe structure and the controllability of operation are additionally solved, avoiding the risk of equipment damage due to the accumulation of thermal stress. It effectively eliminates the impact of flue gas temperature changes on the pipe connection structure, ensuring the long-term stable operation of the inlet section of SCR reactor 4, while realizing the rapid opening and closing of the flue gas channel and flow regulation, providing convenient conditions for equipment maintenance and operating condition adjustment.

[0061] In another embodiment, the system includes a boiler 5 and a flue gas duct 6, which includes a main flue gas duct 61, a first flue gas branch duct 62, and a second flue gas branch duct 63. The first flue gas branch duct 62 is connected to the SCR reactor 4 and is equipped with a first switching valve 621. The second flue gas branch duct 63 is connected to the air inlet of the boiler 5 and is equipped with a second switching valve 631. The flue gas branch duct also includes a third flue gas branch duct 64, one end of which is connected to the SCR reactor 4 and the other end of which is connected to the second flue gas branch duct 63. The connection between the third flue gas branch duct 64 and the second flue gas branch duct 63 is located between the second switching valve 631 and the boiler 5, and the third flue gas branch duct 64 is equipped with a third switching valve 641.

[0062] The main flue gas pipe 61 is the core channel connecting the flue gas source and branch pipes, and can be made of high-temperature resistant metal pipe for centralized transportation of flue gas to be treated. The first flue gas branch pipe 62 is an independent pipe branching from the main flue gas pipe 61 to the SCR reactor 4, which can be connected by flanges or welding. It is equipped with a first on / off valve 621 to control the opening and closing of the denitrification system. The second flue gas branch pipe 63 is a backup channel branching from the main flue gas pipe 61 to the boiler 5 inlet, and can be made of a pipe structure with an insulation layer. It is equipped with a second on / off valve 631 to maintain boiler 5 operation when the denitrification system is shut down. The third flue gas branch pipe 64 is a bypass pipe connecting the outlet of the SCR reactor 4 and the second flue gas branch pipe 63, and can be made of a variable diameter pipe section. It is equipped with a third on / off valve 641 to adjust the mixing ratio of the untreated flue gas and the boiler 5 flue gas to avoid system pressure fluctuations.

[0063] Specifically, during normal denitrification operation of the SCR reactor 4, the first switch valve 621 is open and the second switch valve 631 is closed. Flue gas enters the reactor through the first flue gas branch pipe 62 to complete denitrification before being discharged. When cleaning or maintenance is required, the first switch valve 621 is closed and the second switch valve 631 is opened. Flue gas directly enters the boiler 5 through the second flue gas branch pipe 63, avoiding production interruptions caused by shutdowns. With the second switch valve 631 open, the third flue gas branch pipe 64, by adjusting the opening of the third switch valve 641, can introduce some of the un-denitrated flue gas into the boiler 5 inlet, mixing it with the flue gas passing through the second flue gas branch pipe 63, balancing system pressure and maintaining stable flue gas flow. This pipeline switching process eliminates the need for mechanical cleaning operations, fundamentally eliminating physical damage to the catalyst 41 caused by scraping.

[0064] Compared to existing technologies, current dust removal devices rely on direct contact between the scraper and the catalyst 41, which can easily lead to surface wear of the catalyst 41 over long-term operation. This solution replaces mechanical dust removal with flue gas path switching, avoiding contact between the catalyst 41 and the dust removal components. In existing technologies, a single flue gas path requires shutdown for maintenance, while this solution achieves seamless switching of operating states through a multi-branch design. Simultaneously, the third flue gas branch pipe 64 provides pressure buffering, overcoming the pressure surge problem during switching in traditional bypass systems. This solves the problem of catalyst 41 damage during dust removal. Through the multi-stage switching mechanism of the flue gas duct system 6, while ensuring continuous operation of the denitrification system, the pressure regulation function of the third branch pipe maintains system stability, avoiding damage to the catalyst 41 structure caused by traditional mechanical dust removal methods, and achieving efficient and reliable operation of the flue gas treatment system.

[0065] Furthermore, the flue gas branch pipe also includes a third flue gas branch pipe 64, one end of which is connected to the SCR reaction tower 4 and the other end is connected to the second flue gas branch pipe 63. The connection between the third flue gas branch pipe 64 and the second flue gas branch pipe 63 is located between the second switch valve 631 and the boiler 5. The third flue gas branch pipe 64 is equipped with a third switch valve 641.

[0066] The third flue gas branch pipe 64 is an auxiliary pipe connecting the SCR reactor 4 and the second flue gas branch pipe 63. It can be made of high-temperature resistant metal or ceramic composite pipe, and serves to establish a flow diversion channel between the SCR reactor 4 and the boiler 5. The connection between the third flue gas branch pipe 64 and the second flue gas branch pipe 63 is located between the second switch valve 631 and the boiler 5, and can be achieved through a tee joint or flange connection, ensuring that flue gas can still flow to the boiler 5 through the third flue gas branch pipe 64 even when the second switch valve 631 is closed. The third switch valve 641 is a flow control device installed on the third flue gas branch pipe 64, which can be an electric butterfly valve or a pneumatic gate valve, used to regulate or cut off the flow direction of flue gas within the third flue gas branch pipe 64.

[0067] Specifically, during the cleaning operation of the SCR reactor 4, the second switching valve 631 closes to block the flue gas flow in the second flue gas branch pipe 63, while the third switching valve 641 opens, allowing the flue gas treated by the SCR reactor 4 to enter the downstream section of the second flue gas branch pipe 63 through the third flue gas branch pipe 64 and flow to the boiler 5. This operation ensures that the boiler 5 system can maintain flue gas input during cleaning, avoiding system shutdown. Under normal operating conditions, the opening degree of the third switching valve 641 can be adjusted to balance the flue gas distribution between the SCR reactor 4 and the boiler 5, reducing the airflow load on the catalyst 41 layer. By controlling the coordinated action of the third switching valve 641 and the second switching valve 631, flexible switching of the flue gas path is achieved, reducing the contact frequency between the cleaning mechanism and the catalyst 41, thereby avoiding mechanical scraping damage to the catalyst 41. This allows the continuous operation of the flue gas treatment system to be maintained during cleaning operations, avoiding production efficiency losses due to shutdown. By reducing the airflow load on the catalyst 41 layer through diversion control, the working frequency of the cleaning mechanism is reduced, thereby extending the service life of the catalyst 41. The coordinated control of the third flue gas branch pipe 64 and the valve enables precise regulation of flue gas flow, ensuring stable operation of the system under different operating conditions.

[0068] In addition to the preferred embodiments described above, there are other embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection claimed by this utility model.

Claims

1. An SCR denitrification device, comprising a rotary kiln, a preheater, an ammonia injection system, and an SCR reaction tower, wherein the preheater is located above the rotary kiln and flue gas from the rotary kiln enters the preheater, a flue gas duct is provided between the SCR reaction tower and the preheater, the ammonia injection system injects ammonia into the flue gas so that the ammonia enters the flue gas duct with the flue gas, and the flue gas generated in the rotary kiln enters the flue gas duct from the top of the preheater and then enters the SCR reaction tower for denitrification, characterized in that... The SCR reaction tower is equipped with an installation frame inside and a fixed frame outside the SCR reaction tower. The installation frame is equipped with a dust removal pipe, and the dust removal pipe is equipped with a dust removal rake. The dust removal rake is equipped with nozzles facing the catalyst. The fixed frame is equipped with a feeding mechanism and a blower connected to the dust removal pipe. One end of the dust removal pipe extends to the outside of the SCR reaction tower and is connected to the feeding mechanism. The feeding mechanism drives the dust removal rake to reciprocate through the dust removal pipe. The dust removal pipe is equipped with an anti-clogging fan. The anti-clogging fan blows air into the dust removal pipe during the retraction of the dust removal rake to prevent dust from entering the nozzles and causing blockage.

2. The SCR denitrification device according to claim 1, characterized in that, The cleaning pipe includes an inner cleaning pipe and an outer cleaning pipe. The inner cleaning pipe is mounted on a fixed frame. One end of the outer cleaning pipe is sleeved on the inner cleaning pipe, and the other end extends into the SCR reaction tower. The cleaning rake is connected to and communicates with the outer cleaning pipe. The feeding mechanism is connected to the outer cleaning pipe to drive the outer cleaning pipe to reciprocate relative to the inner cleaning pipe.

3. The SCR denitrification device according to claim 2, characterized in that, The outer cleaning pipe is equipped with a sealing element, which is sealed to the SCR reaction tower.

4. The SCR denitrification device according to claim 1, characterized in that, The mounting frame includes a mounting beam and a suspension frame. The length direction of the mounting beam is consistent with the length direction of the cleaning pipe. One end of the suspension frame is slidably connected to the mounting beam, and the other end is connected to the cleaning pipe.

5. The SCR denitrification device according to claim 1, characterized in that, The cleaning rake is provided in multiple parts, and the multiple cleaning rakes are distributed at equal intervals along the length direction of the cleaning outer tube.

6. The SCR denitrification device according to claim 1, characterized in that, The SCR reaction tower has multiple layers of catalyst, one of which serves as a backup layer. A heating element is located below the catalyst to heat the catalyst above, and a dust removal rake is located above the catalyst.

7. The SCR denitrification device according to claim 1, characterized in that, The top of the SCR reaction tower is provided with a first flue gas inlet section, one end of the flue gas pipe is connected to the flue gas outlet channel of the preheater, and the other end is connected to the first flue gas inlet section.

8. The SCR denitrification device according to claim 7, characterized in that, The first flue gas inlet section is equipped with an expansion joint and a first switching valve.

9. The SCR denitrification device according to claim 7, characterized in that, It also includes a boiler, and the flue gas pipeline includes a main flue gas pipe, a first flue gas branch pipe and a second flue gas branch pipe. The first flue gas branch pipe is connected to the SCR reactor tower and is equipped with a first switching valve. The second flue gas branch pipe is connected to the boiler's air inlet and is equipped with a second switching valve.

10. The SCR denitrification device according to claim 9, characterized in that, The flue gas branch pipe also includes a third flue gas branch pipe, one end of which is connected to the SCR reaction tower and the other end is connected to the second flue gas branch pipe. The connection between the third flue gas branch pipe and the second flue gas branch pipe is located between the second switch valve and the boiler. The third flue gas branch pipe is equipped with a third switch valve.

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