An air preheater

Abstract

The utility model discloses a kind of air preheater, it is related to heat exchange field, including shell, the shell is equipped with flue gas inlet and flue gas outlet, flue gas flows from the flue gas inlet to the flue gas outlet, heat exchange pipe and the support rod connected to the heat exchange pipe are provided between the flue gas outlet and the flue gas inlet, the heat exchange pipe is supported in the shell by the support rod, the flue duct for depositing dust is formed in the heat exchange pipe lower region in the shell, air blowing nozzle is provided in the shell, the air outlet of the air blowing nozzle is set to the flue duct and transports compressed air into the flue duct. The utility model has the advantages that dust is not easy to accumulate inside.

Description

Technical Field

[0001] This utility model relates to the field of heat exchange, specifically to an air preheater. Background Technology

[0002] Co-generation systems combining thermal and solar power are a crucial direction in the current energy transition, achieving a stable power supply by integrating thermal power units with photovoltaic power generation. The air preheater (ABR), a key component of thermal power units, is responsible for recovering waste heat from flue gas to preheat the boiler intake air, thereby improving boiler heat exchange performance and reducing heat loss. During periods when solar power generation dominates, thermal power units require frequent deep peak shaving, leading to deterioration of ABR operating conditions. Ash accumulation becomes a core challenge restricting the system's efficient operation.

[0003] When solar power dominates power generation, the load on thermal power units decreases, the flue gas temperature at the air preheater inlet drops, and a large amount of sticky material adheres to the surface of the air preheater, accelerating ash accumulation. Traditional thermal power units control ash accumulation in the air preheater through periodic steam soot blowing, using superheated steam as the blowing medium. However, when the thermal power unit is under low load, the steam pressure is insufficient, and traditional steam soot blowing cannot effectively remove the ash accumulation. Utility Model Content

[0004] This invention aims to address one of the technical problems in related technologies to a certain extent. To this end, this invention provides an air preheater with the advantage of preventing dust accumulation inside.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: An air preheater includes a housing with a flue gas inlet and a flue gas outlet. Flue gas flows from the flue gas inlet to the flue gas outlet. A heat exchange tube and a support rod connected to the heat exchange tube are disposed between the flue gas outlet and the flue gas inlet. The heat exchange tube is supported within the housing by the support rod. A flue for dust deposition is formed in the area below the heat exchange tube within the housing. An air blowing nozzle is disposed within the housing, with the outlet of the air blowing nozzle facing the flue and delivering compressed air into the flue.

[0006] In this application, dust in the flue gas is deposited in the flue formed below the heat exchange tubes. A support rod is connected to the heat exchange tubes, supporting them within the casing and ensuring their stability during operation. Air nozzles are located inside the casing, with their outlets facing the flue, delivering compressed air into the flue. As the flue gas flows, dust within it enters the flue area below the heat exchange tubes within the casing. Due to the relatively stable flue space and reduced airflow velocity, the dust gradually settles at the bottom of the flue under gravity. Simultaneously, the air nozzles deliver compressed air into the flue. The flow of compressed air disturbs the deposited dust, preventing it from caking within the flue and facilitating its removal from the air preheater by blowing it away with the airflow, thus maintaining flue patency and effectively removing accumulated dust.

[0007] Optionally, an air source for storing compressed air is provided outside the housing, and the air source is connected to the air nozzle through an air blowing pipe.

[0008] The coordination of the air source, air ducts, and air nozzles can flexibly control the purging time and frequency according to the actual operation of the air preheater. For example, after the air preheater has been running for a period of time, the purging system can be started automatically or manually according to the ash accumulation, without the need for large-scale disassembly and cleaning of the equipment. This makes the operation convenient and quick, reducing downtime.

[0009] Optionally, the portion of the air duct located inside the housing is spaced apart from the support rod.

[0010] The air duct and support rod are spaced apart, meaning that they do not contact or overlap each other in the horizontal or vertical direction of the housing and maintain a certain distance. This spacing avoids interaction forces between the two, reduces damage to the support rod caused by duct vibration or airflow impact, improves the stability of the support rod, and also prevents the support rod from blocking the airflow from the air nozzle.

[0011] Optionally, the support rod is hollow, and the portion of the air blowing pipe located inside the housing and the air blowing nozzle are both disposed inside the support rod. A ventilation hole is provided on the side wall of the support rod near the air outlet of the air blowing nozzle.

[0012] When the support rod adopts a hollow structure, its interior provides space for the arrangement of the air blowing duct and nozzles. To maintain its stability, the support rod can be made of carbon steel, alloy steel, or other materials. The portion of the air blowing duct located inside the housing is housed within the hollow support rod, which better protects the duct, preventing direct contact between the duct and the external environment and reducing damage to the duct caused by factors such as collision and corrosion.

[0013] Optionally, the blowing nozzle is inclined relative to the axis of the support rod.

[0014] When the nozzle axis and the support rod axis form a certain angle, the compressed air jet propels axially while simultaneously diffusing radially, forming a conical coverage area.

[0015] Optionally, one end of the air duct near the air nozzle is welded to the surface of the support rod.

[0016] Air blower ducts are typically made of metal, such as stainless steel or carbon steel. The end of the air blower duct near the nozzle is welded to the surface of the support rod. The welded area must ensure good sealing and strength to prevent compressed air leakage. Welding the end of the air blower duct near the nozzle to the support rod creates a unified structure, improving the stability of the air blower duct.

[0017] Optionally, the compressed air ejected from the blower nozzle flows in the same direction as the flue gas, and a dust outlet is provided on the bottom of the housing near the flue gas outlet, and the dust outlet is connected to the flue.

[0018] The compressed air ejected from the blower nozzle flows in the same direction as the flue gas. When the compressed air and flue gas flow in the same direction, according to the fluid dynamics wall adhesion effect, an adhering airflow layer is formed on the inner wall of the casing, effectively suppressing secondary dust re-entrainment. This also makes dust particles easier to detach, thus greatly improving the blowing efficiency. The compressed air velocity is controlled at 1.2-1.5 times the flue gas velocity, and the dust is pushed to the dust outlet area through momentum transfer.

[0019] Optionally, a dust collection box is fixed to the outer surface of the housing, and the dust collection box is located below the dust outlet.

[0020] The dust collection box can be rectangular or cubic in shape for easy installation and dust containment. It is fixed to the outer surface of the housing using methods such as welding or bolting. The dust collection box is located directly below the dust outlet, with its top opening corresponding to the outlet to allow dust to fall smoothly into the box. The dust collection box effectively collects dust discharged from the outlet, preventing dust from scattering and reducing secondary pollution to the environment.

[0021] Optionally, the plurality of the blowing nozzles are arranged sequentially along the length of the flue.

[0022] By arranging multiple air nozzles sequentially along the length of the flue, it is possible to ensure that compressed air covers the target area within the entire length of the flue, avoiding blind spots and thus achieving thorough removal of dust and other impurities from the flue.

[0023] Optionally, a supporting angle steel is also fixed to the inner surface of the bottom wall of the housing, and the blower nozzle is fixed to the supporting angle steel.

[0024] The supporting angle steel has high strength and rigidity, providing stable support for the blower nozzles. During the operation of the air preheater, the blower nozzles are subjected to the reaction force of compressed air and the impact force generated by the flue gas flow. The supporting angle steel can keep the blower nozzles in a fixed position and angle, preventing them from shaking or shifting due to external forces, thus ensuring stable purging effect.

[0025] Optionally, the air outlet of the blower nozzle is flat, with an aspect ratio of (3~5):1.

[0026] The air outlet of the blower nozzle is constructed in a flat shape with a length-to-width ratio of (3~5):1, so that the compressed air is ejected in a fan shape. Compared with a circular air outlet, it can expand the blowing range in the horizontal direction, so that the compressed air forms a more concentrated airflow in a specific direction, and the airflow has sufficient strength to remove dust and improve the blowing effect.

[0027] These features and advantages of this utility model will be disclosed in detail in the following specific embodiments and accompanying drawings. The preferred embodiments or means of this utility model will be shown in detail in conjunction with the accompanying drawings, but are not intended to limit the technical solutions of this utility model. In addition, each of these features, elements and components appearing in the following text and drawings is multiple and is labeled with different symbols or numbers for convenience, but all represent parts with the same or similar structure or function. Attached Figure Description

[0028] The present invention will be further described below with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the air preheater of this utility model; Figure 2 for Figure 1 Schematic diagram of the structure at point A; Figure 3 This is another way to install the blower nozzle in this utility model.

[0029] The components include: 1. Shell; 11. Flue gas inlet; 12. Flue gas outlet; 13. Flue; 14. Dust outlet; 2. Support rod; 21. Ventilation hole; 3. Air nozzle; 31. Air outlet; 4. Air duct; 5. Support angle steel. Detailed Implementation

[0030] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described are intended to explain this utility model and should not be construed as limiting it.

[0031] The terms "an embodiment," "example," or "trademark" used in this specification refer to a particular feature, structure, or characteristic described in connection with the embodiment itself that may be included in at least one embodiment disclosed in this patent. The phrase "in an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0032] Example: like Figure 1 and Figure 2 As shown, this embodiment provides an air preheater, including a housing 1. The housing 1 is provided with a flue gas inlet 11 and a flue gas outlet 12. Flue gas flows from the flue gas inlet 11 to the flue gas outlet 12. A heat exchange tube (not shown in the figure) and a support rod 2 connected to the heat exchange tube are provided between the flue gas outlet 12 and the flue gas inlet 11. The heat exchange tube is supported in the housing 1 by the support rod 2. A flue duct 13 for dust deposition is formed in the area below the heat exchange tube in the housing 1. A blower nozzle 3 is provided in the housing 1. The air outlet 31 of the blower nozzle 3 is set towards the flue duct 13 and delivers compressed air into the flue duct 13.

[0033] The air preheater preheats the flue gas in the boiler tail flue 13 to a certain temperature before it enters the boiler through internal heat exchange tubes. In this embodiment, the air preheater shell 1 has a flue gas inlet 11 and a flue gas outlet 12, which are connected to form a channel for flue gas to enter and exit the air preheater. Heat exchange tubes are arranged between the flue gas outlet 12 and the flue gas inlet 11 to facilitate heat exchange between the flue gas and the air to be preheated. In this embodiment, the heat exchange tubes are located inside the shell 1, with the flue gas flowing outside the tubes and the air to be preheated flowing inside, exchanging heat through the tube walls. After entering the air preheater shell 1 through the flue gas inlet 11, the flue gas flows directly past the outside of the heat exchange tubes, exchanging heat with the air to be preheated inside the tubes. During the heat exchange process, most of the ash in the flue gas is deposited in the flue 13 formed below the heat exchange tubes. A support rod 2 is connected to the heat exchange tubes, supporting them within the shell 1 and ensuring their stability during operation. The blower nozzle 3 is located inside the housing 1, with its outlet 31 facing the flue 13, enabling it to deliver compressed air into the flue 13. During flue gas flow, dust particles are carried by the airflow into the flue 13 area below the heat exchange tubes inside the housing 1. Because the space in the flue 13 is relatively stable, the airflow velocity decreases, and the dust gradually settles at the bottom of the flue 13 under gravity. Simultaneously, the blower nozzle 3 delivers compressed air into the flue 13. The flow of compressed air disturbs the deposited dust, preventing it from caking within the flue 13 and facilitating its removal from the air preheater by blowing it away with the airflow, thus maintaining the flue 13's unobstructed flow and effectively removing accumulated dust.

[0034] An air source for storing compressed air is provided outside the housing 1, and the air source is connected to the air nozzle 3 through the air pipe 4.

[0035] In this embodiment, the air source can be a compressed air tank. The compressed air tank has a certain volume, capable of compressing and storing air to provide a stable air source for subsequent purging operations. Additionally, pressure gauges, safety valves, and other accessories can be equipped on the compressed air tank to monitor and control internal pressure, improving operational safety. The blowing duct 4 connects the air source and the blowing nozzle 3. The blowing duct 4 can be made of metal tubing (such as stainless steel) or pressure-resistant plastic tubing to ensure that compressed air can be smoothly delivered to the blowing nozzle 3. Furthermore, valves can be installed on the duct to control the on / off state of the compressed air and regulate its flow. The coordination of the air source, blowing duct 4, and blowing nozzle 3 can flexibly control the purging time and frequency according to the actual operating conditions of the air preheater. For example, after the air preheater has been running for a period of time, the purging system can be automatically or manually started based on the ash accumulation, eliminating the need for large-scale disassembly and cleaning of the equipment, making operation convenient and quick, and reducing downtime.

[0036] The portion of the air duct 4 located inside the housing 1 is spaced apart from the support rod 2.

[0037] In this embodiment, the air blowing duct 4 and the support rod 2 are spaced apart, meaning that the air blowing duct 4 and the support rod 2 will not contact or overlap each other in the horizontal or vertical direction of the housing 1, and will maintain a certain distance. The spaced-apart arrangement of the air blowing duct 4 and the support rod 2 avoids the interaction force between the two, reduces the damage to the support rod 2 caused by duct vibration or airflow impact, improves the stability of the support rod 2, and also prevents the support rod 2 from blocking the airflow from the air blowing nozzle 3.

[0038] like Figure 3 As shown, in another embodiment, the support rod 2 is hollow, and the part of the air blowing pipe 4 located inside the housing 1 and the air blowing nozzle 3 are both located inside the support rod 2. A ventilation hole 21 is provided on the side wall of the support rod 2 near the air outlet 31 of the air blowing nozzle 3.

[0039] When the support rod 2 adopts a hollow structure, its interior provides space for the arrangement of the air blowing duct 4 and the air blowing nozzle 3. To maintain its stability, the support rod 2 can be made of carbon steel, alloy steel, or similar materials. The portion of the air blowing duct 4 located inside the shell 1 is housed within the hollow support rod 2, which better protects the duct and prevents direct contact between the duct and the external environment, reducing damage caused by collisions, corrosion, or other factors. Simultaneously, the more orderly arrangement of the duct within the support rod 2 facilitates the delivery of compressed air. The air blowing nozzle 3 is also installed within the hollow support rod 2, and its outlet 31 corresponds to the ventilation hole 21 on the side wall of the support rod 2. The ventilation hole 21 guides the compressed air within the hollow support rod 2 into the shell 1 to purge target areas such as the surface of the heat exchange tubes. Specifically, the shape of the air blowing nozzle 3 can be straight, fan-shaped, conical, or similar, as long as it can generate a suitable purging airflow. By placing the air blowing pipe 4 and the air blowing nozzle 3 inside the hollow support rod 2, the space inside the support rod 2 is fully utilized, avoiding the space occupied by additional pipes and nozzles inside the housing 1, making the internal structure of the housing 1 more compact and improving the space utilization rate.

[0040] The blower nozzle 3 is set at an angle relative to the axis of the support rod 2.

[0041] When the axis of the blower nozzle 3 is at a certain angle to the axis of the support rod 2, the compressed air jet propels axially while generating radial diffusion, forming a conical coverage area to expand the purging range.

[0042] In another embodiment, the end of the air duct 4 near the air nozzle 3 is welded to the surface of the support rod 2.

[0043] The air duct 4 is typically made of metal, such as stainless steel or carbon steel. The end of the air duct 4 closest to the air nozzle 3 is welded to the surface of the support rod 2. The welded area must ensure good sealing and strength to prevent compressed air leakage. Welding the end of the air duct 4 closest to the air nozzle 3 to the surface of the support rod 2 makes the air duct 4 and the support rod 2 form a single unit, improving the stability of the air duct 4.

[0044] The compressed air ejected from the blower nozzle 3 flows in the same direction as the flue gas. A dust outlet 14 is provided on the bottom of the housing 1 near the flue gas outlet 12, and the dust outlet 14 is connected to the flue 13.

[0045] In this embodiment, the compressed air ejected from the blower nozzle 3 flows in the same direction as the flue gas. When the compressed air and flue gas flow in the same direction, according to the fluid dynamics wall adhesion effect, an adhering airflow layer is formed on the inner wall of the housing 1, effectively suppressing secondary dust re-entrainment. Furthermore, it makes dust particles easier to detach, thereby greatly improving the blowing efficiency. The compressed air velocity is controlled at 1.2-1.5 times the flue gas velocity, and the dust is pushed to the dust outlet 14 area through momentum transfer.

[0046] A dust collection box is fixed to the outer surface of the housing 1, and the dust collection box is located below the dust outlet 14.

[0047] In this embodiment, the dust collection box can be rectangular or cubic in shape to facilitate installation and dust collection. Furthermore, the dust collection box is fixed to the outer surface of the housing 1 by welding, bolting, or other methods. The dust collection box is located directly below the dust outlet 14, with its top opening corresponding to the dust outlet 14, allowing dust to fall smoothly into the dust collection box. The dust collection box can collect the dust discharged from the dust outlet 14, preventing dust from scattering and reducing secondary pollution to the environment.

[0048] Multiple air nozzles 3 are arranged sequentially along the length of the flue 13.

[0049] In this embodiment, multiple air nozzles 3 are arranged sequentially along the length of the flue 13, ensuring that compressed air covers the target area within the entire length of the flue 13, avoiding blind spots and thus achieving thorough removal of dust and other impurities from the flue 13. When arranging the multiple air nozzles 3 along the length of the flue 13, a uniform distribution can be adopted, i.e., the spacing between adjacent nozzles is equal, to ensure a relatively uniform distribution of compressed air and avoid localized excessively strong or weak blowing. The simultaneous operation of multiple air nozzles 3 generates a powerful airflow, comprehensively blowing away dust within the flue 13, improving blowing efficiency, and reducing dust accumulation within the flue 13.

[0050] A supporting angle steel 5 is also fixed to the inner surface of the bottom wall of the housing 1, and the blower nozzle 3 is fixed to the supporting angle steel 5.

[0051] In this embodiment, the supporting angle steel 5 has high strength and rigidity, which can provide stable support for the blowing nozzle 3. During the operation of the air preheater, the blowing nozzle 3 will be subjected to the reaction force of compressed air and the impact force generated by the flue gas flow. The supporting angle steel 5 can keep the blowing nozzle 3 in a fixed position and angle, and will not shake or shift due to external forces, thereby ensuring stable purging effect.

[0052] The air outlet 31 of the blower nozzle 3 is flat, and its length-to-width ratio is (3~5):1.

[0053] In this embodiment, the air outlet 31 of the blower nozzle 3 is constructed to be flat and the length-to-width ratio is (3~5):1, so that the compressed air is sprayed out in a fan shape. Compared with the circular air outlet 31, the blowing range in the horizontal direction can be expanded, and the compressed air can form a more concentrated airflow in a specific direction. The airflow has sufficient strength to remove dust and improves the blowing effect.

[0054] The above are merely specific embodiments of this utility model, but the scope of protection of this utility model is not limited thereto. Those skilled in the art should understand that this utility model includes, but is not limited to, the contents described in the accompanying drawings and the specific embodiments above. Any modifications that do not depart from the functional and structural principles of this utility model will be included within the scope of the claims.

Claims

1. An air preheater, comprising a housing, wherein the housing is provided with a flue gas inlet and a flue gas outlet, and flue gas flows from the flue gas inlet to the flue gas outlet, characterized in that, A heat exchange tube and a support rod connected to the heat exchange tube are provided between the flue gas outlet and the flue gas inlet. The heat exchange tube is supported in the housing by the support rod. A flue for dust deposition is formed in the area below the heat exchange tube in the housing. A blower nozzle is provided in the housing. The outlet of the blower nozzle is set towards the flue and delivers compressed air into the flue.

2. The air preheater according to claim 1, characterized in that, An air source for storing compressed air is provided outside the housing, and the air source is connected to the air nozzle through an air blowing pipe.

3. The air preheater according to claim 2, characterized in that, The portion of the air duct located inside the housing is spaced apart from the support rod.

4. The air preheater according to claim 2, characterized in that, The support rod is hollow, and the portion of the air blowing pipe located inside the housing and the air blowing nozzle are both located inside the support rod. A ventilation hole is provided on the side wall of the support rod near the air outlet of the air blowing nozzle.

5. The air preheater according to claim 4, characterized in that, The blowing nozzle is inclined relative to the axis of the support rod.

6. The air preheater according to claim 2, characterized in that, The end of the air blowing duct near the air blowing nozzle is welded to the surface of the support rod.

7. The air preheater according to claim 1, characterized in that, The compressed air ejected from the blower nozzle flows in the same direction as the flue gas. A dust outlet is provided on the bottom of the housing near the flue gas outlet, and the dust outlet is connected to the flue.

8. The air preheater according to any one of claims 1-7, characterized in that, Multiple air nozzles are arranged sequentially along the length of the flue.

9. The air preheater according to any one of claims 1-7, characterized in that, The inner surface of the bottom wall of the housing is also fixed with a supporting angle steel, and the blower nozzle is fixed to the supporting angle steel.

10. The air preheater according to any one of claims 1-7, characterized in that, The air outlet of the blower nozzle is flat, with a length-to-width ratio of (3~5):1.

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