Air preheater dry burning system
Patent Information
- Application Number
- CN202522474724.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-21
- Publication Date
- 2026-11-03
- Estimated Expiration
- 2035-11-21
AI Technical Summary
In existing flue gas air preheater systems, the low temperature of the flue gas at the inlet end of the heat exchanger causes ammonium bisulfate to adhere, resulting in blockage, corrosion, and wear on the heat exchanger's heating surfaces, thus affecting its service life.
A first guide plate and an auxiliary flue gas channel are set in the air preheater system. The guide plate divides the flue gas into multiple sub-channels and introduces high-temperature flue gas for mixing, thereby improving the flue gas volume and temperature uniformity at the heat exchanger inlet and preventing ammonium bisulfate from adhering.
It effectively reduces the possibility of blockage, corrosion and wear on the heat exchanger's heating surface, thus extending the heat exchanger's service life.
Smart Images
Figure CN224932772U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of flue gas treatment equipment, and in particular to an air preheater dry-burning system. Background Technology
[0002] Industrial fuel combustion exhaust gases often contain a large amount of heat energy. Traditional methods of treatment involve directly releasing this heat-rich flue gas into the air through conventional boilers, resulting in significant energy waste and the direct release of toxic substances into the air, causing direct environmental damage. With industrial development and increased energy awareness, improving energy efficiency has become crucial, leading to the development of heat exchangers that convert heat from flue gas into water or air for reuse. The heat exchange principle involves introducing a medium to be heated into the channels of an air preheater, while heat-rich flue gas flows between the air preheaters. The flue gas heats the medium in the air preheater, achieving heat exchange, and the heated medium can then be drained out as needed.
[0003] Existing flue gas air preheater systems mainly include a rotary air preheater, a heat exchanger, flue gas ducts, and an air passage. Both the flue gas ducts and the air passage are connected to the rotary air preheater and the preheater. Flue gas first enters the rotary air preheater in the flue gas duct for heat exchange, and then enters the heat exchanger for further heat exchange. Air in the air passage first enters the heat exchanger to exchange heat with the lower-temperature flue gas, and then enters the rotary heat exchanger to exchange heat with the higher-temperature flue gas. Because the flue gas from burning coal contains a large amount of sulfur trioxide, the ammonia injected into the flue gas during the flue gas treatment process reacts with the sulfur trioxide to form ammonium bisulfate. When the flue gas enters the heat exchanger to exchange heat with the air, the flue gas temperature is relatively low. The ammonium bisulfate in the flue gas easily adheres to the heat exchanger's heating surface and adsorbs fly ash particles from the flue gas, potentially causing blockage, corrosion, and wear on the heat exchanger's heating surface.
[0004] After the flue gas enters the heat exchanger from the outlet of the rotary air preheater, the air temperature at the inlet of the heat exchanger is relatively low. After exchanging heat with the flue gas entering the heat exchanger, the amount of heat loss in the flue gas is relatively large. The temperature of the flue gas at the inlet of the heat exchanger is low, and the ammonium bisulfate in the flue gas is easy to liquefy and adhere to the heat-receiving surface at the inlet of the heat exchanger. The adhered ammonium bisulfate adsorbs fly ash particles in the flue gas, which can easily lead to blockage, corrosion and wear of the heat-receiving surface of the heat exchanger, thereby affecting the service life of the heat exchanger. Utility Model Content
[0005] The purpose of this invention is to provide an air preheater dry-burning system that solves the problem of ammonium bisulfate adhering due to the low flue gas temperature at the inlet of the heat exchanger, which leads to blockage, corrosion, and wear on the heat exchanger's heating surface. This system increases the flue gas volume at the inlet of the heat exchanger, effectively preventing the flue gas from adsorbing fly ash particles at the inlet temperature below the liquefaction temperature of ammonium bisulfate, thus reducing the possibility of blockage, corrosion, and wear on the heat exchanger's heating surface and improving the service life of the heat exchanger.
[0006] To achieve the above objectives, the present invention adopts the following technical solution: an air preheater dry-burning system, comprising an air inlet duct, a flue gas duct, a heat exchanger, and an air preheater. Air in the air inlet duct first enters the heat exchanger and then the air preheater. Flue gas in the flue gas duct first enters the air preheater and then the heat exchanger. The flue gas duct includes a first flue gas duct for conveying flue gas to the air preheater and a second flue gas duct for conveying flue gas from the air preheater to the heat exchanger. A first guide plate is provided at the inlet of the second flue gas duct. The first guide plate divides the inlet end of the second flue gas duct into multiple sub-channels distributed along the air intake path in the heat exchanger. The first guide plate is inclined so that the width of the sub-channels near the air intake end of the heat exchanger gradually decreases along the flue gas path, and the air inlets of the multiple sub-channels gradually decrease along the air flow path in the heat exchanger.
[0007] Furthermore, the flue gas passage also includes an auxiliary flue gas passage, one end of which is connected to the first flue gas passage and the other end of which is connected to the second flue gas passage. The auxiliary flue gas passage is equipped with a control switch for controlling the on / off of flue gas.
[0008] Furthermore, a second guide plate is provided at the outlet of the auxiliary flue gas channel, and the plane on which the surface of the second guide plate is located intersects the plane on which the surface of the first guide plate is located, so that the flue gas in the auxiliary flue gas channel mixes with the flue gas in the second flue gas channel.
[0009] Furthermore, the auxiliary flue gas passage is provided with a flue gas outlet passage at its tail end. The flue gas outlet passage is funnel-shaped in the flue gas flow direction, and the second guide plate is located in the flue gas outlet passage.
[0010] Furthermore, the second guide plate is provided in multiple pieces, which are distributed along the flue gas flow path in the second flue gas channel, and the distance between two adjacent second guide plates gradually increases along the flue gas flow direction in the auxiliary flue gas channel.
[0011] Furthermore, the multiple second guide plates include a first plate, a second plate, and a third plate distributed along the direction away from the heat exchanger. The flue gas outlet channel has a first sidewall and a second sidewall. The first sidewall and the second sidewall are distributed along the distribution direction of the air purifier and the heat exchanger. The first plate, the second plate, and the third plate are all located between the first sidewall and the second sidewall, and the first plate is close to the first sidewall. The distance between the first sidewall and the first plate is greater than the distance between the first plate and the second plate.
[0012] Furthermore, an auxiliary plate is provided at the tail end of the first plate, and the auxiliary plate extends inclined toward the heat exchanger.
[0013] Furthermore, the second guide plate is provided with a rotating part, which is located at both ends of the second guide plate. The rotating part is rotatably connected to the pipe wall of the auxiliary flue gas channel, and the auxiliary flue gas channel is provided with a driving component for driving the rotating part to rotate.
[0014] Furthermore, the inner wall of the auxiliary flue gas passage is provided with a limiting part, which is located below the second guide plate to support the second guide plate at the bottom.
[0015] Furthermore, the limiting part is provided on the arc surface of the side away from the second flue gas duct.
[0016] As can be seen from the above, the air preheater dry-burning system provided by this utility model, by setting a first guide plate at the inlet end of the second flue gas channel and setting the first guide plate at an angle, makes the width of the sub-channel near the inlet end of the heat exchange plate gradually decrease in the direction of flue gas flow path, so that the amount of flue gas entering the inlet end of the heat exchanger is greater than the amount of flue gas entering the outlet end of the heat exchanger, thereby reducing the possibility of ammonium bisulfate condensing on the heat exchanger surface and causing the heat exchanger surface to be blocked, corroded and worn. Attached Figure Description
[0017] The present invention will be further described below with reference to the accompanying drawings: Figure 1 This is a schematic diagram of an air preheater dry-burning system according to the present invention; Figure 2 This is a schematic diagram of the first and second guide plates in this utility model; Figure 3 This utility model Figure 2 Enlarged view of point A in the middle; Figure 4 This is a schematic diagram of the auxiliary plate in this utility model; Figure 5 This is a schematic diagram of the second guide plate and the rotating part in this utility model; Figure 6 This is a schematic diagram of the limiting part in this utility model. Detailed Implementation
[0018] 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.
[0019] 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.
[0020] 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.
[0021] like Figure 1 As shown, this utility model provides an air preheater dry-burning system, including an air inlet duct 3, a flue gas duct 4, a heat exchanger 2, and an air preheater 1. The air preheater 1 is a rotary type. Air in the air inlet duct 3 first enters the heat exchanger 2 and then enters the air preheater 1. Flue gas in the flue gas duct 4 first enters the air preheater 1 and then enters the heat exchanger 2 to exchange heat with the air. Specifically, the flue gas duct 4 includes a first flue gas passage 41 that supplies flue gas to the air preheater 1 and a second flue gas passage 42 that supplies flue gas from the air preheater 1 to the heat exchanger 2. The temperature of the flue gas in the first flue gas passage 41 is higher than the temperature of the flue gas in the second flue gas passage 42. Figure 2As shown, a first guide plate 421 is provided at the inlet of the second flue gas passage 42. The first guide plate 421 divides the inlet end of the second flue gas duct 4 into multiple sub-channels distributed along the air intake path in the heat exchanger 2. The first guide plate 421 is inclined, so that the width of the sub-channels near the air intake end of the heat exchanger 2 gradually decreases along the flue gas path, and the air inlet of each sub-channel gradually decreases along the air flow path in the heat exchanger 2; specifically, as shown... Figure 2 As shown, if a first guide plate 421 is provided in the second flue gas passage 42, the air inlet end of the second flue gas passage 42 is divided into two sub-passages, namely the first sub-passage 4211 and the second sub-passage 4212, which are distributed along the air flow path direction in the air inlet passage of the heat exchanger 2. The width of the first sub-passage 4211 gradually decreases in the flue gas flow path of the second flue gas passage 42, so that the first sub-passage 4211 has a large inlet and a small outlet. When the flue gas enters the second flue gas passage 42 from the air preheater 1, A larger amount of flue gas enters the first sub-channel 4211, and the flow velocity of the flue gas in the first sub-channel 4211 gradually increases as the flow rate decreases. This ensures that the flue gas in the first sub-channel 4211 can enter the inlet end of the heat exchanger 2, thereby increasing the amount of flue gas at the inlet end of the heat exchanger 2. This reduces the possibility of ammonium bisulfate adhering to the heat exchanger 2 surface due to excessively low flue gas temperature during the heat exchange process between the flue gas and air, thus reducing the possibility of blockage, corrosion, and wear on the heat exchanger 2 surface. In another embodiment, two first guide plates 421 can also be provided. The two first guide plates 421 divide the end of the second flue gas passage 42 into a first sub-channel 4211, a second sub-channel 4212, and a third sub-channel 4213 distributed along the air intake path of the heat exchanger 2. The first sub-channel 4211 and the second sub-channel 4212 are both in the form of a large inlet and a small outlet, ensuring that the amount of flue gas entering the heat exchanger 2 gradually decreases along the air flow path, further reducing the possibility of blockage, corrosion, and wear on the heat exchanger 2's heating surface due to the adhesion of ammonium bisulfate.
[0022] In this embodiment, as Figure 2As shown, the flue gas duct 4 also includes an auxiliary flue gas channel 43. One end of the auxiliary flue gas channel 43 is connected to the first flue gas channel 41, and the other end is connected to the second flue gas channel 42. The auxiliary flue gas channel 43 is equipped with a control switch 434 for controlling the flow of flue gas. Specifically, by introducing the high-temperature flue gas in the first flue gas channel 41 into the second flue gas channel 42 through the auxiliary flue gas channel 43, the temperature of the flue gas entering the heat exchanger 2 is increased, thereby liquefying the ammonium bisulfate adhering to the heating surface of the heat exchanger 2, and thus improving the service life of the heat exchanger 2. The auxiliary flue gas channel 4 is equipped with a control switch 434, which is a valve device for controlling the flow of fluid or the flow rate. Specifically, it can be implemented by an electric regulating valve or a pneumatic butterfly valve. The valve opening is increased to increase the flow rate of high-temperature flue gas, and the valve opening is decreased to reduce the proportion of high-temperature flue gas.
[0023] To improve the temperature uniformity of the flue gas entering the heat exchanger 2, a second guide plate 431 is provided at the outlet of the auxiliary flue gas passage 43. The plane containing the surface of the second guide plate 431 intersects the plane containing the surface of the first guide plate 421, and the included angle between the two planes is greater than 50°, so that the flue gas in the auxiliary flue gas passage 43 mixes with the flue gas in the second flue gas passage 42. Specifically, both the first guide plate 421 and the second guide plate 431 can be welded or bolted from metal plates. The first guide plate 421 is used to guide the flow direction of the low-temperature flue gas in the second flue gas passage 42, and the second guide plate 431 is installed at an angle to change the flow trajectory of the high-temperature flue gas in the auxiliary flue gas passage 43. The synergistic guiding effect of the first guide plate 421 and the second guide plate 431 causes the high-temperature flue gas and the low-temperature flue gas to form cross flow in the intersection area, generating vortices and turbulence, thereby achieving full mixing. The mixed flue gas has a uniform temperature distribution, avoiding the impact of local high or low temperatures on the heat exchanger 2's heating surface. At the same time, it increases the flue gas temperature, reducing the risk of corrosion and wear on the heat exchanger 2's heating surface and extending the service life of the heat exchanger 2.
[0024] In another embodiment, such as Figure 2As shown, in order to improve the mixing effect of high-temperature flue gas in auxiliary flue gas channel 43 and low-temperature flue gas in second flue gas channel 42, a flue gas outlet channel 435 is provided at the tail end of auxiliary flue gas channel 43. The flue gas outlet channel 435 is funnel-shaped in the flue gas flow direction. The funnel shape of the flue gas outlet channel 435 means that the cross-sectional area at the end of the pipe gradually expands along the flue gas flow direction. Specifically, it can be achieved by using a conical flare or a curved gradually expanding structure. By expanding the flow cross section, the flue gas flow velocity is reduced, thereby increasing the mixing time of high-temperature flue gas and low-temperature flue gas, and thus improving the uniformity of flue gas temperature. When the high-temperature auxiliary flue gas enters the funnel-shaped flue gas outlet channel 435, the flow velocity decreases and the flow direction diffuses outward due to the gradual expansion of the pipe cross-sectional area. The second guide plate 431 is set in the flue gas outlet channel 435, and its plate surface forms an angle with the diffusion direction of the high-temperature flue gas, forcing some flue gas to change its flow direction and cross with the low-temperature main flue gas. The slow-diffusion auxiliary flue gas and the main flue gas form a multi-directional turbulent flow under the guidance of the baffle plate, simultaneously increasing the contact area and mixing time of the two types of flue gas. This achieves thorough mixing of the high-temperature auxiliary flue gas and the low-temperature main flue gas, avoiding thermal stress shocks caused by sudden temperature changes at the inlet of heat exchanger 2. The uniformly distributed flue gas temperature reduces localized overheating or undercooling areas, lowering the risk of deformation and corrosion of the heat exchanger 2's heating surfaces due to temperature differences, thereby extending the equipment's service life.
[0025] In another embodiment, such as Figure 2 As shown, multiple second guide plates 431 are provided, distributed along the flue gas flow path within the second flue gas channel 42. The distance between adjacent second guide plates 431 gradually increases along the flue gas flow direction within the auxiliary flue gas channel 43. Specifically, the distribution of multiple second guide plates 431 along the flue gas flow path within the second flue gas channel 42 means that the guide plates are arranged sequentially according to the mainstream direction of flue gas within the second flue gas channel 42. This can be achieved by using spaced metal plates to form a multi-stage guide structure. The gradual increase in the distance between adjacent second guide plates 431 along the flue gas flow direction within the auxiliary flue gas channel 43 means that the spacing between the guide plates gradually expands from the auxiliary flue gas inlet towards the mixing area. This ensures that the flue gas maintains sufficient contact area even when the flow velocity decreases, avoiding a reduction in mixing efficiency due to the decrease in flow velocity. High-temperature flue gas and low-temperature flue gas can achieve progressive mixing in both the longitudinal and transverse directions, reducing the formation of local turbulence or mixing dead zones, thereby ensuring a more uniform temperature distribution of the mixed flue gas. It significantly improves the temperature uniformity of the flue gas entering the heat exchanger 2, reduces the risk of thermal stress concentration on the heat exchanger 2 surface caused by local temperature differences, and thus extends the service life of the heat exchanger 2.
[0026] To further improve the temperature uniformity after mixing low-temperature flue gas and high-temperature flue gas, such as Figure 3As shown, multiple second guide plates 431 include a first plate 4311, a second plate 4312, and a third plate 4313 distributed along the direction away from the heat exchanger 2. The flue gas outlet channel 435 has a first sidewall 432 and a second sidewall 433. The first sidewall 432 and the second sidewall 433 are distributed along the distribution direction of the air preheater 1 and the heat exchanger 2. The first plate 4311, the second plate 4312, and the third plate 4313 are all located between the first sidewall 432 and the second sidewall 433. The first plate 4311 is close to the first sidewall 432. The distance between the first sidewall 432 and the first plate 4311 is greater than the distance between the first plate 4311 and the second plate 4312. The distance between the first plate 4311 and the second plate 4312 is greater than the distance between the second plate 4312 and the third plate 4313. The second plate 4311... The distance between plate 4312 and the third plate 4313 is greater than the distance between the third plate 4313 and the second sidewall 433. The distribution along the direction away from heat exchanger 2 refers to the three guide plates being arranged in a stepped manner along the flue gas flow path. Specifically, this can be achieved by arranging the plates at intervals along the axial direction of the flue gas outlet channel 435. This gradually changes the spatial distribution of the mixing area, creating multi-stage turbulence. The flue gas outlet channel 435 is designed as a rectangular cross-section pipe extending along the line connecting air preheater 1 and heat exchanger 2, used to constrain the lateral diffusion range of flue gas mixing. When the high-temperature auxiliary flue gas enters the second flue gas channel 42 from the auxiliary flue gas channel 43, the first plate 4311 first performs an initial diversion of the auxiliary flue gas flow. Because the first plate 4311 is close to the first sidewall 432 and has a large spacing, the auxiliary flue gas forms a large diffusion area after the initial diversion. Subsequently, the flue gas enters the area of the second plate 4312. At this time, the plate spacing decreases, increasing the flow velocity and generating a stronger turbulent mixing effect. The third plate 4313 further refines the mixing scale, forming a uniform flue gas temperature field. The constraint effect of the first sidewall 432 and the second sidewall 433 forces the flue gas to undergo multi-stage mixing along the longitudinal flow direction, avoiding temperature stratification caused by lateral diffusion. The stepped guide vane layout forms a gradually narrowing mixing space, achieving temperature field homogenization through progressively enhanced perturbation.
[0027] In another embodiment, such as Figure 4 As shown, an auxiliary plate 4314 is provided at the tail end of the first plate 4311, and the auxiliary plate 4314 extends inclinedly toward the heat exchanger 2. Specifically, the auxiliary plate 4314 is a plate-like structure at the end of the first plate 4311 used for secondary guidance of flue gas. It can be formed by bending or welding metal plates, and its inclination angle is adjusted according to the flue gas flow direction. This structure changes the flue gas flow path by extending the part, so that more high-temperature flue gas gathers at the air inlet end of the heat exchanger 2, effectively reducing the possibility of damage to the heat exchanger 2's heating surface due to the adhesion of ammonium bisulfate at low temperature.
[0028] In another embodiment, such as Figure 5and Figure 6 As shown, rotating parts 4315 are provided at both ends of the second guide plate 431. The rotating parts 4315 are rotatably connected to the pipe wall of the auxiliary flue gas channel 43, and a driving member 437 is installed on the auxiliary flue gas channel 43 to drive the rotating parts 4315 to rotate. The rotating parts 4315 are used to enable the second guide plate 431 to rotate around its axis. The driving member 437 is a device for providing rotational power. When the driving member 437 is activated, the rotating parts 4315 drive the second guide plate 431 to rotate around its two-end axis, changing the angle between the second guide plate 431 and the outlet of the auxiliary flue gas channel 43. When the flue gas in the auxiliary flue gas channel 43 passes through the second guide plate 431, the flow direction deflects with the change of the angle of the second guide plate 431, forming turbulent mixing regions of different intensities with the flue gas in the second flue gas channel 42. When the angle of the guide plate increases, the flue gas mixing region extends downstream of the second flue gas channel 42; when the angle decreases, the mixing region is closer to the outlet of the auxiliary flue gas channel 43. By adjusting the angle of the second guide plate 431 in real time, the mixing intensity can be dynamically controlled according to the difference in flue gas flow or temperature, ensuring that the two flue gases are fully mixed.
[0029] To further improve the stability of the second guide vane 431, such as Figure 6 As shown, the inner wall of the auxiliary flue gas passage 43 is provided with a limiting part 436. The limiting part 436 is located below the second guide plate 431 to support the second guide plate 431 at the bottom. By supporting the second guide plate 431 below the limiting part 436, the tail ends of two adjacent second guide plates 431 are effectively prevented from sticking together and affecting the outflow efficiency of flue gas in the auxiliary flue gas passage 43.
[0030] Furthermore, the limiting part 436 is provided with an arc surface on the side away from the second flue gas passage 4. The arc surface guides the flow of flue gas and effectively prevents the flue gas from impacting the end of the limiting part 436.
[0031] 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 air preheater dry-burning system, comprising an air inlet duct, a flue gas duct, a heat exchanger, and an air preheater, wherein air in the air inlet duct first enters the heat exchanger and then the air preheater, and flue gas in the flue gas duct first enters the air preheater and then the heat exchanger, wherein the flue gas duct includes a first flue gas duct for conveying flue gas to the air preheater and a second flue gas duct for conveying flue gas from the air preheater to the heat exchanger, characterized in that... The second flue gas passage is provided with a first guide plate at the flue gas inlet. The first guide plate divides the inlet end of the second flue gas passage into multiple sub-channels distributed along the air intake path in the heat exchanger. The first guide plate is inclined so that the width of the sub-channels near the air intake end of the heat exchanger gradually decreases along the flue gas path, and the air inlet of each sub-channel gradually decreases along the air flow path in the heat exchanger.
2. The air preheater dry-burning system according to claim 1, characterized in that, The flue gas passage also includes an auxiliary flue gas passage, one end of which is connected to the first flue gas passage and the other end of which is connected to the second flue gas passage. The auxiliary flue gas passage is equipped with a control switch for controlling the on / off of flue gas.
3. The air preheater dry-burning system according to claim 2, characterized in that, A second guide plate is provided at the outlet of the auxiliary flue gas channel. The plane on which the surface of the second guide plate is located intersects the plane on which the surface of the first guide plate is located, so as to mix the flue gas in the auxiliary flue gas channel with the flue gas in the second flue gas channel.
4. The air preheater dry-burning system according to claim 2, characterized in that, The auxiliary flue gas passage is provided with a flue gas outlet passage at its tail end. The flue gas outlet passage is funnel-shaped in the flue gas flow direction, and the second guide plate is located in the flue gas outlet passage.
5. The air preheater dry-burning system according to claim 4, characterized in that, The second guide plate is provided in multiple pieces, which are distributed along the flue gas flow path in the second flue gas channel. The distance between two adjacent second guide plates gradually increases along the flue gas flow direction in the auxiliary flue gas channel.
6. The air preheater dry-burning system according to claim 5, characterized in that, The multiple second guide plates include a first plate, a second plate, and a third plate distributed along the direction away from the heat exchanger. The flue gas outlet channel has a first sidewall and a second sidewall. The first sidewall and the second sidewall are distributed along the distribution direction of the air purifier and the heat exchanger. The first plate, the second plate, and the third plate are all located between the first sidewall and the second sidewall, and the first plate is close to the first sidewall. The distance between the first sidewall and the first plate is greater than the distance between the first plate and the second plate.
7. The air preheater dry-burning system according to claim 6, characterized in that, An auxiliary plate is provided at the tail end of the first plate, and the auxiliary plate extends inclined toward the heat exchanger.
8. The air preheater dry-burning system according to claim 3, characterized in that, The second guide plate is provided with a rotating part, which is located at both ends of the second guide plate. The rotating part is rotatably connected to the pipe wall of the auxiliary flue gas channel. The auxiliary flue gas channel is provided with a driving component for driving the rotating part to rotate.
9. The air preheater dry-burning system according to claim 8, characterized in that, The inner wall of the auxiliary flue gas passage is provided with a limiting part, which is located below the second guide plate to support the second guide plate at the bottom.
10. The air preheater dry-burning system according to claim 9, characterized in that, The limiting part is set on the arc surface away from the second flue gas passage.