Heat transfer structure of air preheater

Abstract

The utility model relates to a boiler air and flue gas system technical field especially a kind of air preheater heat transfer structure.A kind of air preheater heat transfer structure, including the air preheating pipe of array arrangement, each air preheating pipe is fixed with helical inner core, the outer edge of inner core is welded and fixed with air preheating pipe inner wall, air preheating pipe is used for cold air to flow through, the gap between air preheating pipe is used for hot air to flow from top to bottom.The air preheater heat transfer structure includes the air preheating pipe of array arrangement, each air preheating pipe is fixed with helical inner core, to realize firm connection, the outer edge of inner core is fixed with the inner wall of air preheating pipe by welding mode, in actual use process, the internal space of air preheating pipe is used for cold air to flow through, and the gap formed between air preheating pipe is used for hot air to flow from top to bottom, by such structural design makes cold air and hot air to be able to flow in different area respectively, to realize heat transfer function further.

Description

Technical Field

[0001] This utility model relates to the technical field of boiler flue gas systems, and in particular to a heat transfer structure for an air preheater. Background Technology

[0002] A primary and secondary air preheater system is installed in the boiler's tail flue. The heat from the flue gas at the tail end undergoes convective heat exchange in the air preheater, ensuring the temperature of the air entering the air chamber reaches the coal's crushing temperature. The secondary air entering the furnace also provides better combustion support. During boiler combustion, different coal types have different ignition temperatures for the blast air. The requirements gradually increase for lignite, bituminous coal, and anthracite. Higher blast temperatures increase the explosiveness of coal particles, allowing for better crushing and improving the coal's burnout, thus effectively reducing operating costs for the enterprise.

[0003] Common air preheater arrangements include in-line and staggered configurations. In in-line air preheaters, the flue gas flows vertically downwards during boiler operation, which effectively prevents ash accumulation and blockage to some extent. However, this arrangement does not achieve optimal utilization of flue gas heat. Staggered air preheaters, due to the greater bypass area for the flue gas, offer some benefits in increasing air temperature. However, this arrangement is prone to ash blockage, affecting boiler operating cycles. With increasingly stringent environmental regulations, the amount of ammonia water required for denitrification has increased, leading to increased ammonia escape at the tail end and increased ash accumulation, thus impacting tail-end heat absorption.

[0004] In view of the above-mentioned shortcomings, the designer actively researched and innovated in order to create an air preheater heat transfer structure that would have greater industrial application value. Utility Model Content

[0005] To solve the above-mentioned technical problems, the purpose of this utility model is to provide a heat transfer structure for an air preheater.

[0006] The present invention discloses a heat transfer structure for an air preheater, comprising an array of air preheater tubes, each air preheater tube having a fixed spiral inner core, the outer edge of the inner core being welded and fixed to the inner wall of the air preheater tube, the air preheater tubes being used for cold air to flow through, and the gaps between the air preheater tubes being used for hot air to flow through from top to bottom.

[0007] The heat transfer structure of this air preheater includes air preheating tubes arranged in an array. Inside each air preheating tube is a spiral inner core. To achieve a stable connection, the outer edge of the inner core is fixed to the inner wall of the air preheating tube by welding. In actual use, the internal space of the air preheating tube is used for cold air to flow through, while the gaps formed between the air preheating tubes are used for hot air to flow from top to bottom. This structural design allows cold air and hot air to flow in different areas, thereby achieving the heat transfer function.

[0008] Furthermore, multiple heat-conducting fins are evenly arranged on the inner wall of the air preheater.

[0009] The air preheater has multiple heat-conducting ribs evenly arranged on its inner wall. These ribs are directly connected to the inner wall of the air preheater. This structural design allows the air preheater to perform its basic functions while also leveraging the heat-conducting ribs on its inner wall to further assist in heat transfer.

[0010] Furthermore, the ends of the heat-conducting ribs extending towards the center of the air pre-tube are tapered.

[0011] The heat-conducting ribs installed on the inner wall of the air preheater tube have specific morphological characteristics at their ends. Specifically, the end of the heat-conducting rib extending towards the center of the air preheater tube is cone-shaped. This morphological design creates a suitable structural relationship between the heat-conducting ribs and the air preheater tube, allowing them to better integrate into the internal space of the air preheater tube.

[0012] Furthermore, the empty pre-tubes are arranged in multiple rows, with adjacent rows staggered.

[0013] The air preheating tubes are not arranged in a single row, but rather in a multi-row structure composed of multiple air preheating tubes. In terms of arrangement, adjacent rows of air preheating tubes are staggered. Through this multi-row and staggered arrangement design of air preheating tubes, the air preheating tubes form an orderly and specific distribution in the overall structure, thereby improving the contact efficiency between the hot airflow and the air preheating tubes.

[0014] Furthermore, the outer surface of the air preheater is provided with multiple sets of deployable baffles.

[0015] Multiple sets of deployable baffles are directly connected to the outer surface of the air preheater tube. By setting deployable baffles on the outer surface of the air preheater tube, the air preheater tube can not only perform its basic heat transfer functions, but also regulate the airflow around the air preheater tube with the help of the baffles on the outer surface.

[0016] Furthermore, the baffle is movably mounted on the mounting base via a shaft, and the mounting base is fixed to the side wall of the empty pre-tube.

[0017] The baffle is movably mounted on the mounting base via a shaft, while the mounting base is fixed to the side wall of the empty preheating tube. This connection method allows the baffle to be stably associated with the empty preheating tube with the help of the mounting base, thus realizing the movable characteristic of the baffle and ensuring the installation stability of the baffle on the side wall of the empty preheating tube.

[0018] Furthermore, connecting plates are fixed on the shafts on both sides of the baffle. The connecting plates are arranged on both sides of the pull rod, and the pull rod has an oblong hole in the middle that mates with the connecting plates.

[0019] Connecting plates are fixed on the shafts on both sides of the baffle. These connecting plates are respectively set on both sides of the pull rod. At the same time, the middle of the pull rod has an oblong hole that matches the shaft between the connecting plates. Through this structural design, the baffle can form a linkage relationship with the pull rod with the help of the connecting plates. The distribution of the connecting plates on both sides of the pull rod and the matching of the oblong hole with the shaft provide the necessary structure for the subsequent adjustment of the baffle.

[0020] Furthermore, one end of the pull rod passes through the mounting wall panel, and a locking part is installed on the outer side of the mounting wall panel. The locking part cooperates with the groove at the tail end of the pull rod to complete the locking and positioning of the pull rod.

[0021] One end of the pull rod passes through the mounting wall panel. A locking part is installed on the outside of the mounting wall panel, and the locking part will cooperate with the groove at the end of the pull rod. Through this connection and cooperation method, the pull rod can be locked and positioned. This not only realizes the installation association between the pull rod and the mounting wall panel, but also ensures the stable fixation of the pull rod in a specific position by means of the cooperation between the locking part and the groove at the end of the pull rod.

[0022] Furthermore, the locking part includes a locking housing, inside which is a through push rod, one end of which can engage with a groove in the pull rod.

[0023] The locking housing has a through-hole top rod, one end of which can engage with the groove of the pull rod. Through this structure and engagement, the locking part uses the locking housing to accommodate and limit the top rod. At the same time, the engagement between the top rod and the groove of the pull rod provides basic component support for the subsequent locking function of the pull rod.

[0024] Furthermore, a baffle is installed inside the locking housing on the push rod, and a tension spring is sleeved between the baffle and one end of the locking housing. A pull ring is fixed on the side of the push rod away from the pull rod.

[0025] A baffle plate is installed on the top rod located inside the locking housing. A tension spring is sleeved between the baffle plate and one end of the locking housing. At the same time, a pull ring is fixed on the side of the top rod away from the pull rod. Through this component assembly relationship, the baffle plate, tension spring and top rod form a cooperative structure inside the locking housing. The pull ring provides a convenient force application component for the operation of the top rod. All components cooperate with each other to provide structural support for the top rod to realize the locking or unlocking action, ensuring the stable realization of the locking function.

[0026] By means of the above-described solution, the present invention has at least the following advantages: By utilizing the limited heating surface and arrangement space of the in-line air preheater, the heat absorption at the tail end is further increased, thereby raising the air temperature. Spiral guide vanes are arranged inside the 40-65mm air preheater tubes, with the inlet side of the vanes welded and fixed to the air preheater tubes. This causes the cold air to rotate along with the guide vanes as it passes through the air preheater tubes, ensuring that the cold air exchanges heat with the tube wall. Furthermore, the spiral arrangement prolongs the residence time of the cold air inside the tubes, allowing for more effective heat absorption and increasing the air temperature. This structure also allows for a large-diameter tube arrangement, enabling the air preheater to meet requirements without high resistance, reducing fan power consumption, and saving air preheater arrangement space—a win-win situation.

[0027] Multiple sets of deployable baffles on the outer surface of the air preheater can slow down the hot airflow by adjusting the deployment angle, thereby improving the heating efficiency of the cold air inside the air preheater. When the hot airflow passes through the gaps in the air preheater, the deployed baffles can change its trajectory, slowing down its flow rate, prolonging its residence time, and allowing for more thorough contact with the outer surface of the air preheater, thus enabling the air preheater to absorb heat efficiently.

[0028] The heat-conducting ribs on the inner wall of the air preheater can quickly transfer heat to the inside of the tube. Combined with the spiral inner core inside the tube, which allows the cold air to rotate against the wall and prolong its residence time, the cold air can fully absorb heat. Furthermore, when adjusting the baffle, the linkage between the pull rod and the connecting plate, the fixing of the mounting base, and the positioning of the locking part can stably maintain the baffle state. This not only takes advantage of the drag reduction of the large-diameter air preheater but also works in conjunction with the inner core and heat-conducting ribs to efficiently transfer heat in a limited space, helping the cold air reach the temperature required for coal combustion.

[0029] The above description is only an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, the preferred embodiments of this invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show a certain embodiment of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the staggered arrangement of the empty pre-tubes of this utility model; Figure 3 This is a cross-sectional view of the empty pre-tube of this utility model; Figure 4 This is a schematic diagram of the structure of this utility model with a baffle; Figure 5 This is a utility model Figure 4 A magnified view of a portion of the image; In the diagram: 1. Empty pre-tube; 2. Inner core; 3. Heat-conducting rib; 4. Baffle; 5. Mounting base; 6. Connecting plate; 7. Pull rod; 8. Mounting wall panel; 9. Locking housing; 10. Top rod; 11. Baffle plate; 12. Tension spring. Detailed Implementation

[0032] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0033] See Figure 1 and Figure 3 The heat transfer structure of this air preheater uses arrayed air preheating tubes 1 as the core load-bearing component. Inside each air preheating tube 1, a spiral inner core 2 is fixed, and the outer edge of the inner core 2 is securely connected to the inner wall of the air preheating tube 1 by welding. During operation, cold air flows through the air preheating tubes 1, while hot air flows downwards through the gaps between the tubes. The spiral inner core 2 guides the cold air inside the air preheating tubes 1 to form a rotating flow, increasing the contact area and residence time between the cold air and the inner wall of the air preheating tubes 1, allowing the cold air to... The heat transferred by the air preheating tube 1 is absorbed more fully. At the same time, the welding and fixing method between the inner core 2 and the inner wall of the air preheating tube 1 not only ensures the structural stability of the inner core 2 inside the air preheating tube 1 and avoids loosening caused by airflow impact, but also assists in heat conduction. The array arrangement of the air preheating tube 1 and the design of the separate flow of hot and cold airflows can ensure that the hot airflow is in full contact with the outer surface of the air preheating tube 1, so that the air preheating tube 1 can efficiently absorb the heat of the hot airflow and transfer it to the cold air inside the tube, realizing efficient heat exchange between the hot and cold airflows and improving the overall heat transfer efficiency.

[0034] See Figure 3 The air preheating tube 1 has multiple heat-conducting ribs 3 evenly arranged on its inner wall. These heat-conducting ribs 3 are directly connected to the inner wall of the air preheating tube 1 and form an integral heat transfer structure. When the hot airflow comes into contact with the outer surface of the air preheating tube 1 and transfers heat to the tube wall, the heat-conducting ribs 3 on the inner wall of the air preheating tube 1 can quickly receive the heat transferred from the tube wall. At the same time, since the heat-conducting ribs 3 are evenly distributed on the inner wall of the air preheating tube 1, the heat can be diffused more evenly into the internal space of the air preheating tube 1. The presence of the heat-conducting ribs 3 greatly increases the heat transfer area inside the air preheating tube 1, allowing the cold air flowing through the air preheating tube 1 to come into more full contact with the heat-conducting ribs 3 and the inner wall of the air preheating tube 1, thereby improving the efficiency of cold air absorbing heat. On the other hand, the evenly arranged heat-conducting ribs 3 can avoid local heat accumulation or uneven heat transfer inside the air preheating tube 1, ensuring the overall heat transfer performance of the air preheating tube 1 is stable, thereby helping the air preheater to achieve a more efficient and stable heat exchange effect.

[0035] The heat-conducting ribs 3, installed on the inner wall of the air preheater tube 1 and used to assist heat transfer, have tapered ends extending towards the center of the air preheater tube 1. This tapered design allows the heat-conducting ribs 3 to form a more suitable structural shape within the internal space of the air preheater tube 1. It avoids excessively occupying the space inside the air preheater tube 1 for cold air to flow through, while maintaining a stable connection with the inner wall of the air preheater tube 1 for efficient heat transfer. On the one hand, the tapered ends reduce the resistance of the heat-conducting ribs 3 to the flow of cold air inside the air preheater tube 1, preventing the cold air from being obstructed and affecting the flow efficiency, ensuring that the cold air can flow smoothly inside the air preheater tube 1 and make full contact with the heat-conducting ribs 3. On the other hand, the tapered ends make the distribution of the heat-conducting ribs 3 inside the air preheater tube 1 more reasonable, further optimizing the heat diffusion path inside the air preheater tube 1, allowing the heat absorbed by the heat-conducting ribs 3 to be transferred more evenly to the surrounding cold air. See Figure 2 The air pre-tubes 1, which are the core heat exchange components, are not arranged in a single row, but are composed of multiple air pre-tubes 1 forming a multi-row structure. The adjacent rows of air pre-tubes 1 are arranged in a staggered manner. The staggered arrangement of multiple rows allows the air pre-tubes 1 to be distributed more densely and orderly in the limited installation space, which greatly increases the overall coverage of the air pre-tubes 1. When the hot air flows through the gaps between the air pre-tubes 1, it has to go around more air pre-tubes 1, which prolongs the residence time of the hot air in the air pre-tube 1 area. This allows the hot air to have more sufficient contact with the outer surface of the air pre-tubes 1, thereby improving the efficiency of the air pre-tubes 1 in absorbing the heat of the hot air.

[0036] See Figure 4 The outer surface of the air preheating tube 1 is specially equipped with multiple sets of deployable baffles 4. These baffles 4 are directly connected to the outer surface of the air preheating tube 1 and can be adjusted in deployment according to actual heat exchange requirements. When the hot air flows through the gaps between the air preheating tubes 1, the deployed baffles 4 can form a reasonable obstruction to the hot air flow. The deployable baffles 4 can flexibly adjust the flow state of the hot air flow around the air preheating tube 1. By changing the deployment angle, the flow rate of the hot air flow is slowed down, the contact time between the hot air flow and the outer surface of the air preheating tube 1 is extended, and the air preheating tube 1 can absorb the heat in the hot air flow more fully, thereby improving the efficiency of the air preheating tube 1 in transferring heat to the cold air inside the tube.

[0037] The baffle 4, used to regulate the hot airflow, is movably mounted on the mounting base 5 via a shaft. The mounting base 5 is fixed to the side wall of the air preheating pipe 1, forming a stable and movable connection between the baffle 4 and the air preheating pipe 1. The mounting base 5, fixed to the side wall of the air preheating pipe 1, provides a solid mounting foundation for the baffle 4, preventing it from loosening or shifting under the impact of the hot airflow, ensuring the long-term stable function of the baffle 4. At the same time, the fixing method of the mounting base 5 also makes the position of the baffle 4 on the side wall of the air preheating pipe 1 more precise, ensuring the consistency of multiple sets of baffles 4 when regulating the hot airflow. The baffle 4 is movably mounted on the mounting base 5 via a shaft, giving it flexible unfolding and retraction functions. Operators can easily adjust the angle of the baffle 4 according to the heat exchange requirements, which facilitates the control of the contact state between the hot airflow and the air preheating pipe 1 to improve heat exchange efficiency.

[0038] Connecting plates 6 are fixed on the shafts on both sides of the baffle 4. These connecting plates 6 are arranged on both sides of the pull rod 7, and the pull rod 7 has an oblong hole in the middle that mates with the shaft between the connecting plates 6. Through this assembly relationship, a linkage structure is constructed between the baffle 4 and the pull rod 7. The advantages of this structural design are significant. The connecting plates 6 are fixed on the shafts on both sides of the baffle 4 and are arranged on both sides of the pull rod 7, which makes the connection between the baffle 4 and the pull rod 7 more balanced and avoids the baffle 4 from being stuck due to unilateral force. At the same time, the engagement between the oblong hole and the shaft between the connecting plate 6 provides flexible space for the angle adjustment of the baffle 4, ensuring that the baffle 4 can rotate smoothly during the unfolding or retraction process without being stuck due to structural limitations.

[0039] The pull rod 7, used to adjust the baffle 4, passes through the mounting wall plate 8 at one end. A locking part is installed on the outer side of the mounting wall plate 8, and the locking part cooperates with the groove at the tail end of the pull rod 7. Through this connection and cooperation, a locking and positioning structure for the pull rod 7 is formed. The mounting wall plate 8 provides stable support for the pull rod 7, ensuring that the pull rod 7 maintains linear movement during the adjustment process and avoiding deviation that affects the synchronous adjustment accuracy of the baffle 4. At the same time, the cooperation between the locking part on the outer side of the mounting wall plate 8 and the groove at the tail end of the pull rod 7 can quickly achieve locking and positioning after the pull rod 7 is adjusted to the correct position, preventing the pull rod 7 from shifting under the impact of hot airflow or its own gravity, ensuring that the baffle 4 is stably maintained at the set angle, and ensuring the consistency of the hot airflow adjustment effect.

[0040] See Figure 5The locking part includes a basic supporting component called a locking housing 9. Inside the locking housing 9, there is a push rod 10 that can pass through it, and one end of the push rod 10 can cooperate with the groove of the pull rod 7. Through this component composition and cooperation, a basic locking structure for the pull rod 7 is constructed. The locking housing 9 provides a stable space for the push rod 10 to accommodate and limit its movement, which can constrain the movement trajectory of the push rod 10 and ensure that the push rod 10 always moves in the preset direction. This avoids the push rod 10 being unable to accurately cooperate with the groove of the pull rod 7 due to deviation, thus ensuring the accuracy of the locking action. At the same time, the locking housing 9 can also protect the push rod 10, reduce the corrosion and interference of external dust and airflow on the push rod 10, and extend the service life of the push rod 10.

[0041] A baffle 11 is installed on the top rod 10 located inside the locking housing 9. A tension spring 12 is connected between the baffle 11 and one end of the locking housing 9. The tension spring 12 is sleeved on the outside of the top rod 10. At the same time, a pull ring is fixed on the side of the top rod 10 away from the pull rod 7. Through this component assembly method, the locking part forms a complete structure with a stable elastic reset function. The tension spring 12 is connected between the baffle 11 and the locking housing 9. When the pull ring is pulled to move the top rod 10 away from the pull rod 7, the baffle 11 will move synchronously with the top rod 10 and stretch the tension spring 12. When the pull ring is released, the contraction force of the tension spring 12 will pull the baffle 11, thereby causing the top rod 10 to automatically reset towards the pull rod 7, ensuring that the top rod 10 can be accurately embedded in the pull rod 7. The groove completes the locking, eliminating the need for manual pushing of the push rod 10. This improves the efficiency of the locking action and prevents locking failure due to untimely or incomplete reset of the push rod 10. The pull ring on the push rod 10 provides a convenient force application point for unlocking. Operators can easily pull the push rod 10 to unlock by simply pulling the pull ring. The operation is simple and effortless. At the same time, the baffle 11 not only provides a stable force support point for the tension spring 12, but also limits the range of movement of the push rod 10 within the locking housing 9, preventing the push rod 10 from detaching from the locking housing 9 due to excessive movement. The locking housing 9 provides a unified protection and limiting space for the push rod 10, the baffle 11, and the tension spring 12, preventing the components from being affected by external dust and airflow, and ensuring the long-term stability of the elastic performance of the tension spring 12.

[0042] Finally, the following points should be noted: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection", and "linkage" should be interpreted broadly, and can be mechanical or electrical connections, or internal connections between two components, or direct connections. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may change. Secondly: The accompanying drawings of the embodiments disclosed in this utility model only involve the structures involved in the embodiments disclosed in this utility model. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this utility model can be combined with each other. Finally: The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. An air preheater heat transfer structure, comprising an array of air preheater tubes (1), characterized in that: Each air pre-tube (1) has a spiral inner core (2) fixed inside. The outer edge of the inner core (2) is welded to the inner wall of the air pre-tube (1). The air pre-tube (1) is used for cold air to pass through, and the gap between the air pre-tubes (1) is used for hot air to pass through from top to bottom.

2. The air preheater heat transfer structure according to claim 1, characterized in that: Multiple heat-conducting ribs (3) are evenly arranged on the inner wall of the air preheater (1).

3. The air preheater heat transfer structure according to claim 2, characterized in that: The end of the heat-conducting rib (3) extends towards the center of the air pre-tube (1) in a conical shape.

4. The air preheater heat transfer structure according to claim 3, characterized in that: The empty pre-tubes (1) are arranged in multiple rows, with adjacent rows staggered.

5. The air preheater heat transfer structure according to any one of claims 1-4, characterized in that: The outer surface of the empty pre-tube (1) is provided with multiple sets of deployable baffles (4).

6. The air preheater heat transfer structure according to claim 5, characterized in that: The baffle (4) is movably mounted on the mounting base (5) via a shaft, and the mounting base (5) is fixed on the side wall of the empty pre-tube (1).

7. The air preheater heat transfer structure according to claim 6, characterized in that: Connecting plates (6) are fixed on the shafts on both sides of the baffle (4). The connecting plates (6) are arranged on both sides of the pull rod (7). The pull rod (7) has a waist-shaped hole in the middle that mates with the connecting plates (6).

8. The air preheater heat transfer structure according to claim 7, characterized in that: One end of the pull rod (7) passes through the mounting wall panel (8). A locking part is installed on the outside of the mounting wall panel (8). The locking part cooperates with the groove at the tail end of the pull rod (7) to lock and position the pull rod (7).

9. The air preheater heat transfer structure according to claim 8, characterized in that: The locking part includes a locking housing (9), and a through top rod (10) is provided inside the locking housing (9). One end of the top rod (10) can be engaged with the groove of the pull rod (7).

10. The air preheater heat transfer structure according to claim 9, characterized in that: The top rod (10) is located inside the locking housing (9) and a baffle (11) is installed. A tension spring (12) is sleeved between the baffle (11) and one end of the locking housing (9). A pull ring is fixed on the side of the top rod (10) away from the pull rod (7).

Images