Biomass boiler air preheater system with flue gas guide and self-cleaning functions

Abstract

The present application relates to the technical field of flue dust treatment, and particularly relates to a biomass boiler air preheater system with flue gas guiding and self-cleaning functions. The air preheater comprises a main shell, a flue gas inlet and outlet, an air inlet and outlet, a heat exchange layer plate, a flue gas layer, an air layer, a Z-shaped heat conducting plate and a rotating guide vane as a vortex sweeping self-cleaning structure. The flue gas layer and the air layer are alternately arranged and separated by the heat exchange layer plate. The Z-shaped heat conducting plate arranged inside forms a baffle structure. The rotating guide vane is arranged at the corner of the heat conducting plate. The high-speed low-pressure wind and the low-speed high-pressure wind are induced to intersect to form a separation vortex, so that the leeward surface is swept in the reverse direction. The air preheater has the advantages of high heat exchange efficiency, strong self-cleaning capacity and long running cycle, and is suitable for the air preheating system of a medium or large biomass boiler.

Description

Technical Field

[0001] This invention relates to the technical field of flue gas dust treatment, specifically to a biomass boiler air preheater system with flue gas diversion and self-cleaning functions. Background Technology

[0002] Biomass boilers, as a clean energy system using renewable biomass resources as fuel, have been widely used in industrial and civil sectors in recent years. To improve boiler thermal efficiency and reduce flue gas temperature, air preheaters, as heat recovery devices, have become an indispensable component of biomass boiler systems. Their basic function is to preheat the combustion air entering the boiler using high-temperature flue gas, thereby improving combustion efficiency and saving fuel consumption.

[0003] However, traditional air preheater structures generally have the following problems: the flue gas flow path is simple and the disturbance is insufficient, resulting in insufficient heat exchange and low heat transfer efficiency; biomass fuel has a high ash content and fine ash, which easily accumulates on the surface of heat exchange tube bundles or heat exchange plates to form a dust layer, which can cause pipe blockage in severe cases, affect heat exchange performance, and even cause the system pressure difference to rise and force shutdown; tar and alkali metal substances entrained in the flue gas are prone to corrosion and scaling problems, shortening the service life of the equipment.

[0004] Therefore, there is an urgent need to design a biomass boiler air preheater system with flue gas guiding and self-cleaning functions. While ensuring heat recovery efficiency, it can optimize flue gas flow organization, achieve efficient ash removal of heat exchange surfaces, and ensure long-term stable operation, so as to meet the usage requirements of biomass boiler systems under high ash, high temperature, and variable load conditions. Summary of the Invention

[0005] To address the above problems, the present invention aims to provide a biomass boiler air preheater system with flue gas guiding and self-cleaning functions, comprising: a main shell, a flue gas inlet, a flue gas outlet, an air inlet, an air outlet, a heat exchange plate, a flue gas layer, an air layer, a Z-shaped heat conduction plate, and a swirl guide vane.

[0006] The flue gas layer and the air layer are arranged alternately and separated by a heat exchange plate;

[0007] Z-shaped heat-conducting plates extending in orthogonal directions are provided in the flue gas layer and the air layer;

[0008] The Z-shaped heat-conducting plate is connected to heat exchange plates on both sides, and two adjacent Z-shaped heat-conducting plates and two heat exchange plates form a flue gas flow channel or air flow channel.

[0009] As a preferred technical solution, the swirl guide vane is disposed in the flue gas flow channel and connected to two heat exchange plates on both sides respectively; the swirl guide vane is located at the corner of the Z-shaped heat conduction plate, has a head and a tail, and its cross-sectional shape is a lift concave-convex airfoil, including a concave surface and a convex surface, and its concave surface is correspondingly arranged with the corner convex surface of the Z-shaped heat conduction plate.

[0010] As a preferred technical solution, the deflection angle from the head to the tail of the swirl guide vane satisfy:

[0011]

[0012] in, The angle at the corner of the Z-shaped heat-conducting plate.

[0013] As a preferred technical solution, the geometric center of the swirl guide vane is aligned with the corner line of the Z-shaped heat-conducting plate.

[0014] As a preferred technical solution, the pointing line of the head of the swirling guide vane is parallel to the windward side of the Z-shaped heat-conducting plate relative to the flue gas flow direction, and the tail of the swirling guide vane points to the leeward side of the Z-shaped heat-conducting plate relative to the flue gas flow direction.

[0015] As a preferred technical solution, the geometric center of the swirl guide plate is located at the equidistant point of the line connecting the corners of the two Z-shaped heat-conducting plates.

[0016] As a preferred technical solution, the convex surface of the swirling guide vane forms a low-pressure zone between the opposing Z-shaped heat-conducting plates, forming a high-speed, low-pressure airflow; the concave surface of the swirling guide vane forms a high-pressure zone between the opposing Z-shaped heat-conducting plates, forming a low-speed, high-pressure airflow.

[0017] As a preferred technical solution, the high-speed low-pressure wind and the low-speed high-pressure wind converge at the tail to generate separation vortices, forming a vortex purging zone.

[0018] As a preferred technical solution, with the flue gas flow direction as the forward direction: the windward side of the Z-shaped heat-conducting plate on the left side of the swirling guide plate is directly swept by the incoming flue gas, while the leeward side is located in the vortex sweeping zone and is swept by the separated vortex in the opposite direction; the windward side of the Z-shaped heat-conducting plate on the left side of the swirling guide plate is swept by the convex airflow, while the leeward side is swept by the lateral airflow pushed by the head.

[0019] As a preferred technical solution, the swirl guide vane is formed by casting or hollow expansion molding; the Z-shaped heat conduction plate is formed by stamping; and the main shell, flue gas inlet, flue gas outlet, air inlet, air outlet, heat exchange plate, flue gas layer, air layer, Z-shaped heat conduction plate and swirl guide vane are connected by welding.

[0020] As a preferred technical solution, the welding is resistance welding.

[0021] As a preferred technical solution, the main shell, flue gas inlet, flue gas outlet, air inlet, air outlet, heat exchange plate, flue gas layer, air layer, Z-shaped heat conduction plate and swirl guide plate are integrally formed by metal 3D printing.

[0022] As a preferred technical solution, the 3D printing is completed using selective laser melting (SLM), and the printing material is high-temperature resistant nickel-based alloy powder with a melting point of not less than 1200℃.

[0023] As a preferred technical solution, the components of the 3D printed structure are connected by layer-by-layer scanning and melting to form continuous metal grain boundaries, and after printing, they are subjected to uniform hot isostatic pressing to eliminate micropores and crack defects.

[0024] Technical Notes:

[0025] Plate heat exchangers (air preheaters) have the advantage of simple structure, but the large-area flat plate structure increases the proportion of the airflow boundary layer, causing poor flue gas flow and dust accumulation. This invention further designs a Z-shaped heat-conducting plate, which can provide a certain amount of gas turbulence and heat exchange contact area. However, the Z-shaped heat-conducting plate has a leeward side, which is prone to airflow backflow and dust accumulation. On this basis, a swirling guide vane with a lift concave-convex airfoil cross section is added, so that its tail points towards the leeward area, while the convex back faces the upper leeward side. In this way, the separation vortex at the tail will generate a downward sweeping effect, which will reverse the leeward side, realize the airflow cyclone, enhance heat exchange convection, and avoid dust deposition. The incoming airflow will be split at the head, and the airflow on the convex back will be squeezed and pushed to generate outward sweeping on the right leeward side, providing cyclone initiation and self-cleaning.

[0026] Beneficial effects:

[0027] This invention utilizes alternating flue gas and air layers, separated by heat exchange plates, to form a multi-channel heat exchange unit. Combined with a Z-shaped heat-conducting plate, this creates a complex flue gas disturbance path, enhancing heat flow disturbance and heat exchange capacity. In particular, the swirling guide vanes located within the flue gas flow channels, with their lift-generating concave-convex airfoil structure and deflection arrangement, induce high-speed, low-pressure airflow and low-speed, high-pressure airflow at the corners of the Z-shaped heat-conducting plate, forming a separation vortex zone at the tail end. This strengthens the flue gas flow disturbance effect, thereby achieving a self-cleaning effect for dust particles.

[0028] The precise angular relationship and relative arrangement of the swirling guide vanes and Z-shaped heat-conducting plates in this invention effectively construct forward and reverse purging paths, taking into account the flushing and ash-removing effects on both the windward and leeward sides. The entire unit is manufactured using a metal 3D printing integrated molding process, achieving high structural integration, strong sealing, and excellent precision control, effectively reducing manufacturing and maintenance costs. In summary, this air preheater system improves heat exchange efficiency while effectively reducing ash accumulation and blockage, making it suitable for biomass boiler systems requiring long-term stable operation. Attached Figure Description

[0029] Figure 1 This is a side view schematic diagram of the air preheater of the present invention;

[0030] Figure 2 This is a top view schematic diagram of the flue gas layer and air layer of the present invention;

[0031] Figure 3 This is a schematic diagram showing the arrangement of the swirl guide vanes according to the present invention;

[0032] Figure 4 This is a schematic diagram of the swirl guide vane of the present invention;

[0033] Figure 5 This is a schematic diagram of the cyclone region of the present invention. Detailed Implementation

[0034] To enhance understanding of the present invention, the present invention will be further described in detail below with reference to embodiments. These embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0035] Example 1

[0036] according to Figure 1 As shown, this embodiment provides a biomass boiler air preheater system with flue gas guiding and self-cleaning functions, aiming to solve the problems of low heat exchange efficiency, easy clogging of flue gas due to ash accumulation, and short cleaning cycle of traditional air preheaters. This air preheater achieves the combined functions of efficient flue gas guiding and automatic ash cleaning by optimizing the internal airflow channel structure and enhancing the vortex interference mechanism.

[0037] The air preheater has a compact structure and mainly includes the following components: a main shell, a flue gas inlet, a flue gas outlet, an air inlet, an air outlet, a heat exchange plate 1, a flue gas layer 2, an air layer 3, a Z-shaped heat-conducting plate 4, and a swirl guide vane 5. The main shell is a sealed metal cavity structure that supports and protects the normal operation of the internal components. The main shell has an external flue gas inlet and outlet for introducing high-temperature flue gas and discharging residual gas, respectively; it also has an air inlet and outlet for introducing cold air and discharging preheated air.

[0038] In terms of structural arrangement, the flue gas layer 2 and the air layer 3 are arranged alternately inside the main shell, such as... Figure 1 As shown, it is separated by heat exchange plate 1.

[0039] Each layer of the structure does not interfere with the others, forming an independent airflow channel. Multiple Z-shaped heat-conducting plates 4 are installed inside the flue gas layer 2. The bends in the Z-shaped structure cause the flue gas to deflect multiple times during its flow within the channel, thereby extending the airflow path and enhancing the heat exchange effect. Figure 2 As shown. At the same time, a Z-shaped heat-conducting plate with a similar structure to the flue gas layer is also provided in the air layer 3 to ensure that the air has a sufficient disturbance path in the heat exchange layer, thereby achieving effective heat exchange with the flue gas layer.

[0040] To further improve heat exchange efficiency and achieve self-cleaning function, swirl guide vanes 5 are installed in each corner area of ​​the flue gas layer 2, such as... Figure 3 As shown. This guide vane is made of a high-temperature resistant alloy material and adopts a concave-convex airfoil cross-section structure, including a concave surface 53 and a convex surface 54, as shown. Figure 4 As shown, the concave surface 53 faces the high-pressure area along the flue gas flow path, while the convex surface 54 faces the low-pressure area, thus creating a bidirectional flow of high-speed low-pressure air and low-speed high-pressure air from the leading edge to the trailing edge of the guide vane. Especially at the tail 52, the two airflows converge to form a separated vortex, constituting a locally intense vortex sweeping zone.

[0041] It is worth mentioning that the deflection angle α between the head 51 and the tail 52 of the guide vane is designed to be greater than the angle β of the Z-shaped heat conduction plate (i.e., α>β) to ensure that the eddies generated by the disturbance have a stronger desorption capacity. This deflection angle not only enhances the shear strength of the flue gas at the bend, but also significantly increases the impact force of the flue gas on the deposits on the heat exchange surface, effectively suppressing the occurrence of ash accumulation.

[0042] The geometric center of each guide vane is aligned with the line connecting the corners of the Z-shaped heat-conducting plate 4, and its geometric center is precisely located at the equidistant point of the line connecting the corners of two adjacent Z-shaped heat-conducting plates. This design allows the guide vanes to generate disturbances at the optimal airflow convergence point, thereby achieving a good balance between structural symmetry and flow disturbance intensity.

[0043] During the forward flow of the flue gas, it first impacts the windward side of the Z-shaped heat-conducting plate, forming primary turbulence. Subsequently, it encounters the swirling guide vane 5, whose convex surface 54 applies tangential wind pressure to the windward side, further intensifying the turbulence. Meanwhile, the high-pressure, low-velocity zone formed by its concave surface 53 induces counter-current flow on the leeward side, achieving secondary stripping of deposited particles. Finally, a stable separation vortex zone is formed at the tail 52 of the guide vane, continuously cleaning particle deposits on the leeward side, thus completing the active self-cleaning operation. Figure 5 As shown.

[0044] All the main components of the above structure, such as the main shell, heat exchange plate 1, Z-shaped heat conduction plate 4, and swirl guide plate 5, are integrally formed by metal 3D printing. The specific printing technology adopts selective laser melting (SLM), and the printing material used is high-temperature nickel-based alloy powder with a melting point of not less than 1200℃, which meets the long-term thermal stability requirements of biomass boilers under high-temperature operation conditions.

[0045] After printing, the entire structure undergoes hot isostatic pressing (HIP) to further eliminate internal defects such as micropores and cracks, resulting in a uniform and dense metal grain structure. This improves the overall mechanical strength, thermal stability, and corrosion resistance of the air preheater. Because all key components are formed through layer-by-layer melting, there are no mechanical gaps between the printed components, enabling continuous metal grain boundary transitions and further ensuring the integrity and efficiency of the heat conduction path.

[0046] To verify the performance of the air preheater, the following industrial-grade operating condition experiments were conducted:

[0047] Installation environment: The air preheater will be installed between the flue gas outlet and the air inlet of a 20MW biomass boiler to replace the original plate air preheater.

[0048] Operating time: The continuous operating cycle is 90 days. During the operation, the ash condition of the heat exchange surface is observed every 10 days.

[0049] Temperature difference comparison: Compared with the traditional structure, under the conditions of flue gas inlet temperature of 320℃ and air inlet temperature of 25℃, the air outlet temperature of this air preheater is increased to 145℃, which is 12.8℃ higher than the control air preheater.

[0050] Differential pressure monitoring: Under the same fuel conditions, the flue gas differential pressure was continuously monitored and found to be stable at around 180 Pa, without any obvious upward trend, indicating that the flow guiding structure can effectively prevent ash accumulation and blockage.

[0051] Dust removal efficiency assessment: Through infrared thermal imaging analysis and manual disassembly inspection, the thickness of the deposits on the heat exchange surface was significantly reduced compared to the previous stage, and there were almost no deposits in some corner areas. The vortex purging effect was significantly better than that of conventional straight plate heat exchanger structures.

[0052] Maintenance cycle analysis: Traditional air preheaters require shutdown and maintenance every 30 days, while in this embodiment, no significant efficiency decline or ash accumulation blockage was found in the air preheater within 90 days, extending the maintenance cycle to more than three times the original.

[0053] In summary, the air preheater structure provided in this embodiment achieves a synergistic dual function of "heat conduction and heat exchange + self-cleaning" through the complex angled design of the Z-shaped heat-conducting plate and the concave-convex disturbance structure of the swirling guide vanes. Simultaneously, the use of metal 3D printing manufacturing technology ensures the integrated precision construction of components and long-term reliability, making it particularly suitable for biomass boiler systems with high requirements for flue gas quality. This structure has significant engineering practical value, effectively reducing operating and maintenance costs, improving boiler thermal efficiency, and showing promising prospects for large-scale application.

[0054] Example 2

[0055] This embodiment provides a biomass boiler air preheater with a vortex purging self-cleaning structure, manufactured using traditional metal stamping and welding processes. It aims to balance low-cost mass production with structural and functional optimization, achieving a complex flow guiding structure and good operating performance without relying on 3D printing equipment. It is suitable for general small and medium-sized biomass boiler systems.

[0056] The air preheater structure mainly includes: main shell, flue gas inlet, flue gas outlet, air inlet, air outlet, heat exchange plate 1, flue gas layer 2, air layer 3, Z-shaped heat conduction plate 4, and swirl guide vane 5.

[0057] Structural layout description:

[0058] The main shell is a one-piece welded structure, made of 304 stainless steel plate with a thickness of 3mm, formed by CNC shearing, bending, splicing and welding. Inside, several parallel heat exchange plates 1 are arranged to divide the main shell space into alternating flue gas layers 2 and air layers 3. The heat exchange plates 1 are made of stainless steel using a stamping process, with reinforcing ribs and positioning edges on both sides, and a thickness of approximately 2.5mm. This allows them to withstand airflow disturbances and thermal stress impacts, ensuring structural stability during long-term operation of the air preheater.

[0059] Z-type heat-conducting plate structure and layout:

[0060] Each flue gas layer 2 and air layer 3 is equipped with multiple sets of Z-shaped heat-conducting plates 4. The heat-conducting plates are formed by stamping and bending heat-resistant carbon steel sheets, and are arranged in a Z-shaped path. The two sides of the Z-shaped heat-conducting plates are fixed to the adjacent heat exchange plates 1 by welding. The two adjacent heat-conducting plates and the upper and lower heat exchange plates form a flue gas channel or air channel. The Z-shaped structure makes the flue gas or air flow through the air preheater tortuous and deflected multiple times, thereby significantly extending the residence time of the airflow in the air preheater and improving the heat exchange efficiency.

[0061] To prevent the heat-conducting plate from loosening under the scouring of high-temperature flue gas, each corner of the Z-shaped heat-conducting plate is equipped with a limiting groove, which is then inserted into the buckle structure on the heat exchange plate and spot-welded to ensure overall firmness.

[0062] Structure and installation of the swirl guide vane:

[0063] A swirling guide vane 5 is installed at the corner of the Z-shaped heat-conducting plate in each flue gas layer. This guide vane features a concave-convex airfoil cross-section design, formed by hydraulic stretching and stamping of 1mm thick 310S stainless steel sheet, followed by directional bending using a mold to create a swirling structure with a certain deflection angle α. The head 51 and tail 52 have a certain angle in the planar direction, specifically: α = β + 15°, where β is the included angle of the Z-shaped heat-conducting plate bend, typically 60°, thus the deflection angle α of the guide vane is 75°.

[0064] The guide vane 5 is welded and fixed to the upper and lower heat exchange plates via connecting plates on both sides. Its head points towards the windward side of the Z-shaped heat conduction plate, while its tail guides the airflow to converge towards the leeward side. The geometric center of the guide vane is set at the midpoint of the line connecting the bends of the Z-shaped heat conduction plate. The installation and positioning rely on specially designed positioning holes and auxiliary clamps to ensure that the angle of each guide vane is accurate and the deformation is controllable during the welding process.

[0065] Flue gas guiding and self-cleaning principle:

[0066] After entering the air preheater through the flue gas inlet, the flue gas first flows into the lower flue gas layer 2, where it forms multiple deflections under the guidance of the Z-shaped heat-conducting plate. At each deflection, the guide vane 5 splits the incoming flow into two streams: a low-pressure, high-speed airflow forms on the convex side, and a high-pressure, low-speed airflow forms on the concave side. These two streams converge at the tail of the guide vane, forming a local vortex and creating a dynamic purging zone within the space.

[0067] Structural simulation and subsequent field measurements show that the vortex purging zone can generate reverse disturbances on the leeward side of the Z-shaped heat-conducting plate, thereby repeatedly peeling off the deposited dust particles, which are eventually discharged from the air preheater along with the main airflow, eliminating the need for manual or external cleaning and effectively extending the operating cycle.

[0068] In addition, because the guide vanes are set at multiple bends, multiple evenly distributed and periodically alternating turbulence purging zones are formed inside the air preheater. This structural design breaks the problems of airflow short-circuiting and ash accumulation dead zones in traditional air preheaters, and improves the overall thermal efficiency.

[0069] Welding method description:

[0070] In this embodiment, all structural connections are assembled using a combination of resistance welding and argon arc welding:

[0071] Argon arc welding is used at the joints of the main shell to improve the airtightness of the weld.

[0072] The heat exchange plate is welded to the inner wall of the main shell by resistance spot welding, and the weld points are evenly distributed to reduce thermal deformation;

[0073] The connection between the Z-shaped heat-conducting plate and the heat exchange plate adopts a fillet weld process, with 3 weld points at each corner;

[0074] The swirl guide vane is fixed by welding lugs, with no fewer than four welding points to ensure fatigue resistance.

[0075] This embodiment constructs the core component of the air preheater with complex angles and turbulence structures through stamping and welding. Without relying on advanced printing technology, it achieves high-strength assembly, high-disturbance heat exchange, and stable self-cleaning functions. This structure boasts advantages such as low manufacturing cost, strong adaptability, and high ash-cleaning efficiency, making it suitable for retrofitting or constructing medium-sized biomass boiler systems and possessing promising prospects for engineering application.

[0076] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A biomass boiler air preheater system with flue gas flow guiding and self-cleaning functions, comprising: The main shell, the flue gas inlet, the flue gas outlet, the air inlet, the air outlet, the heat exchange layer plate (1), the flue gas layer (2), the air layer (3), the Z-shaped heat conduction plate (4) and the rotating guide vane (5); The flue gas layer (2) and the air layer (3) are arranged alternately and are separated by the heat exchange layer plate (1); The Z-shaped heat conduction plate (4) extending along the orthogonal direction is arranged in the flue gas layer (2) and the air layer (3); Two sides of the Z-shaped heat conduction plate (4) are connected with the heat exchange layer plate (1) respectively, and two Z-shaped heat conduction plates (4) and two heat exchange layer plates (1) adjacent to each other enclose a flue gas flow channel or an air flow channel; The rotating guide vane (5) is arranged in the flue gas flow channel, and two sides of the rotating guide vane (5) are connected with the heat exchange layer plate (1) respectively; the rotating guide vane (5) is located at the corner of the Z-shaped heat conduction plate (4), has a head portion (51) and a tail portion (52), the cross-sectional shape of the rotating guide vane (5) is in the shape of a lift concave-convex airfoil, and the rotating guide vane (5) comprises a concave surface (53) and a convex surface (54); the concave surface (53) of the rotating guide vane (5) is arranged correspondingly to the corner convex surface of the Z-shaped heat conduction plate (4).

2. The biomass boiler air preheater system with flue gas guiding and self-cleaning functions according to claim 1, characterized in that: The deflection angle of the head (51) to the tail (52) of the spin-inducing guide vane (5) satisfies: ； wherein is the angle of the corner of the Z-shaped heat-conducting plate (4).

3. The biomass boiler air preheater system with flue gas guiding and self-cleaning functions according to claim 1, characterized in that: The geometric center of the rotating guide vane (5) is flush with the corner connecting line of the Z-shaped heat conduction plate (4).

4. The biomass boiler air preheater system with flue gas guiding and self-cleaning functions according to claim 1, characterized in that: The geometric center of the rotating guide vane (5) is located at the bisector point of the corner connecting line of the two Z-shaped heat conduction plates (4).

5. The biomass boiler air preheater system with flue gas guiding and self-cleaning functions according to claim 1, characterized in that: The convex surface (54) of the rotating guide vane (5) is a low-pressure area between the opposite Z-shaped heat conduction plates (4), and forms high-speed low-pressure wind; the concave surface (53) of the rotating guide vane (5) is a high-pressure area between the opposite Z-shaped heat conduction plates (4), and forms low-speed high-pressure wind.

6. The biomass boiler air preheater system with flue gas guiding and self-cleaning functions according to claim 5, characterized in that: The high-speed low-pressure wind and the low-speed high-pressure wind converge at the tail portion (52) to induce a separation vortex, and form a vortex sweeping area; With the flue gas flow direction as the front direction: The windward surface of the Z-shaped heat conduction plate (4) on the left side of the rotating guide vane (5) is directly swept by the inflowing flue gas, and the leeward surface is located in the vortex sweeping area and is swept by the separation vortex in the opposite direction.

7. The biomass boiler air preheater system with flue gas guide and self-cleaning functions according to claim 5, characterized in that: The high-speed low-pressure wind and the low-speed high-pressure wind converge at the tail portion (52) to induce a separation vortex, and form a vortex sweeping area; With the flue gas flow direction as the front direction: The windward surface of the Z-shaped heat conduction plate (4) on the right side of the rotating guide vane (5) is swept by the airflow of the convex surface (54), and the leeward surface is swept by the lateral airflow pushed by the head portion (51).

8. The biomass boiler air preheater system with flue gas guiding and self-cleaning functions according to claim 1, characterized in that: The main shell, the flue gas inlet, the flue gas outlet, the air inlet, the air outlet, the heat exchange layer plate (1), the flue gas layer (2), the air layer (3), the Z-shaped heat conduction plate (4) and the rotating guide vane (5) are integrally formed by metal 3D printing.

9. The biomass boiler air preheater system with flue gas guiding and self-cleaning functions according to claim 8, characterized in that, The 3D printing is completed by selective laser melting (SLM), and the printing material is high-temperature-resistant nickel-based alloy powder with a melting point not lower than 1200 DEG C.

10. The biomass boiler air preheater system with flue gas guiding and self-cleaning functions according to claim 8, characterized in that, The components of the 3D printing formed structure are connected by layer-by-layer scanning and melting, and are uniformly treated by hot isostatic pressing after printing to eliminate micropore and crack defects.

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