A soot-resistant flue gas heat exchanger

Abstract

The utility model relates to a kind of soot deposition prevention flue gas heat exchanger, the flue gas heat exchanger includes shell body, and the heat exchange pipe being set in the shell body, the pipeline of the heat exchange pipe is connected with heat exchange medium supply device intercommunication;The heat exchange pipe is twisted sheet pipe;The twisted sheet pipe includes twisted sheet and base pipe, and the twisted sheet is helical structure.The utility model is by being arranged twisted sheet pipe in the inside of flue gas heat exchanger, and limit twisted sheet in twisted sheet pipe is helical structure, and the twisted sheet of helical structure can enhance the disturbance of tube outer flue gas, form turbulent effect, improve heat exchange efficiency;The twisted sheet of helical structure can also change local flue gas flow direction, dynamic airflow scouring, prevent ash deposition in flue gas to form bridge, increase the service life of flue gas heat exchanger.

Description

Technical Field

[0001] This utility model relates to the field of heat transfer equipment technology, and in particular to a flue gas heat exchanger that prevents ash accumulation. Background Technology

[0002] Heat exchangers are used in many industrial sectors (such as metallurgy, power, cement, and chemical industries) to transfer heat, and heat exchange tubes are one of the most important components in the heat transfer process of heat exchangers.

[0003] In harsh operating environments, such as prolonged exposure to dusty flue gas or corrosive media, the accumulation of ash and wear on heat exchange tubes can severely impact equipment efficiency and lifespan. Ash buildup reduces the heat transfer coefficient, increases flow resistance, and in severe cases, bridging can obstruct the normal flow of materials or gases, leading to equipment damage and malfunctions. Wear, on the other hand, can cause thinning of the tube walls and even leaks, resulting in serious accidents. Therefore, addressing the problem of severe ash accumulation in flue gas heat exchangers under complex operating conditions is of great significance. Utility Model Content

[0004] To solve the above-mentioned technical problems, this utility model provides a flue gas heat exchanger that prevents ash accumulation. The flue gas heat exchanger is equipped with a twisted tube inside, and the twisted tube has a spiral structure. The spiral structure of the twisted tube can enhance the disturbance of the flue gas outside the tube, form a turbulence effect, and improve the heat exchange efficiency. The spiral structure of the twisted tube can also change the local flue gas flow direction, dynamically scour the airflow, and prevent ash in the flue gas from depositing and bridging.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] In the first aspect, this utility model provides a flue gas heat exchanger that prevents ash accumulation. The flue gas heat exchanger includes a shell and a heat exchange tube disposed in the shell. The pipe of the heat exchange tube is connected to a heat exchange medium supply device.

[0007] The heat exchange tube is a twisted-plate tube; the twisted-plate tube includes twisted plates and a base tube, and the twisted plates have a spiral structure.

[0008] In this invention, flue gas enters the shell of the flue gas heat exchanger through the flue gas inlet, undergoes heat exchange on the outside of the twisted-plate tubes, and finally exits through the flue gas outlet on the other side of the shell. The heat exchange tubes are connected to a heat exchange medium supply device, which can distribute the heat exchange medium into the base tube of the twisted-plate tubes. The heat exchange medium flows within the base tube and exchanges heat with the flue gas outside the tube, absorbing heat from the flue gas. The twisted plates inside the flue gas heat exchanger have a spiral structure. This spiral structure enhances the turbulence of the flue gas outside the tube, creating a turbulence effect and improving heat exchange efficiency. The spiral structure also changes the local flue gas flow direction, dynamically scouring the airflow and preventing ash deposition and bridging in the flue gas. Furthermore, the spiral structure increases the heat exchange area, optimizes the heat exchanger structure, and reduces the equipment volume.

[0009] As a preferred technical solution of this utility model, the twisted tubes are arranged in a staggered pattern in the flue gas heat exchanger.

[0010] In this invention, when the twisted tubes are arranged in a staggered pattern in the flue gas heat exchanger, the turbulence of the flue gas outside the tubes can be enhanced, the flue gas boundary layer can be broken, thereby improving the convective heat transfer coefficient, enhancing the heat transfer effect, and reducing the overall size of the heat exchanger.

[0011] As a preferred technical solution of this utility model, the twisted tubes are arranged in a straight line in the flue gas heat exchanger.

[0012] In this invention, when the twisted tubes are arranged in a straight line in the flue gas heat exchanger, the flue gas flow path is relatively smooth and the resistance loss of the flue gas is small. At the same time, a straight-flow space is formed between the twisted tubes, which is conducive to the blowing off of ash in the flue gas.

[0013] As a preferred technical solution of this utility model, the flue gas heat exchanger includes at least two of the aforementioned twisted-blade tubes, for example, 2, 10, 20, 50, 100 or 200, but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0014] As a preferred technical solution of this utility model, the twisted piece includes a first twisted piece and a second twisted piece respectively disposed on both sides of the base tube.

[0015] As a preferred technical solution of this utility model, the first twisted piece and the second twisted piece are symmetrically distributed along the base tube.

[0016] As a preferred technical solution of this utility model, the twisted piece includes at least two first twisted pieces, such as 2, 10, 50, 100 or 200, but not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0017] As a preferred technical solution of this utility model, the distance between the first twisted pieces is 80-120mm, for example, it can be 80mm, 90mm, 100mm, 110mm or 120mm, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0018] As a preferred technical solution of this utility model, the range of the helical angle θ of the twisted piece is 0°<θ≤180°, for example, it can be 5°, 30°, 60°, 90°, 120°, 150° or 180°, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0019] The method of using the anti-ash-accumulation flue gas heat exchanger provided by this utility model includes: flue gas enters the shell of the flue gas heat exchanger from the flue gas inlet, the flue gas located outside the twisted tube exchanges heat with the heat exchange medium in the base tube, and then is discharged through the flue gas outlet on the other side of the shell.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects:

[0021] This invention improves the structure of a flue gas heat exchanger to obtain a twisted-fin tube type flue gas heat exchanger. The twisted-fin tube type heat exchanger can enhance the disturbance of flue gas outside the tube, form a turbulence effect, and improve heat exchange efficiency. It can also change the local flue gas flow direction, dynamically scour the airflow, prevent ash deposition and bridging in the flue gas, and increase the service life of the flue gas heat exchanger. Furthermore, the spiral structure of the twisted fins can increase the heat exchange area, optimize the heat exchanger structure, and reduce the equipment volume. Attached Figure Description

[0022] Figure 1 This is a left view of the flue gas heat exchanger provided in Embodiment 1 of this utility model.

[0023] Figure 2 This is a front view of the flue gas heat exchanger provided in Embodiment 1 of this utility model.

[0024] Figure 3 This is a schematic diagram of the arrangement of the twisted fin tubes in the flue gas heat exchanger provided in Embodiment 1 of this utility model.

[0025] Figure 4 This is a schematic diagram of the twisted tube provided in Embodiment 1 of this utility model.

[0026] Figure 5 This is a schematic diagram of the arrangement of the twisted fin tubes in the flue gas heat exchanger provided in Embodiment 2 of this utility model.

[0027] Among them, 1-twisted tube; 101-twisted plate; 102-base tube; 1011-first twisted plate; 1012-second twisted plate; 2-flue gas inlet; 3-shell; 4-heat exchange medium supply device; 5-flue gas outlet; 6-ash hopper. Detailed Implementation

[0028] The technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of this utility model and do not represent or limit the scope of protection of this utility model. The scope of protection of this utility model is determined by the claims.

[0029] At present, the anti-dust accumulation technology used in the industrial field is mostly achieved through heat exchanger structure optimization or auxiliary dust removal devices, including: (1) heat exchange tube fin structure optimization (U-shaped fins, flower fins, H-shaped fins, etc.); (2) dynamic dust removal technology (steam soot blowing, high-pressure air soot blowing system, etc.); (3) materials and surface treatment (dustproof coating, etc.); (4) layout optimization (rotatable heat exchanger, etc.), but there are the following disadvantages: (1) structural limitations: although most fin designs can alleviate dust accumulation, they cannot completely eliminate the dust accumulation problem on the leeward side or in complex flow field areas; (2) energy consumption and maintenance costs: dynamic dust removal technology consumes a lot of energy, increasing operating costs; surface coatings need to be maintained regularly; (3) insufficient wear resistance: traditional fin materials and structures are easily worn in high-speed dust-laden airflow, affecting lifespan.

[0030] CN106679465B discloses a flue gas heat exchanger that prevents ash accumulation, wear, and low-temperature corrosion. It includes a heat exchanger shell with an external medium inlet and an external medium outlet. A finned tube bundle arranged in a row is disposed within the heat exchanger shell. Each finned tube bundle includes several interconnected base tubes and several fin groups mounted on the base tubes. An internal medium inlet and an internal medium outlet are provided on the base tubes. The fin groups are fin groups arranged axially on the outer wall of the base tubes. Each fin group includes two quadrilateral fins located on both sides of at least one base tube. Each fin has a groove on its inner side that matches the outer wall of the base tube. The fins are connected to the base tubes through the groove. The outer walls are connected, and two fins are located on the same plane perpendicular to the axis of the base tube, with a gap greater than zero between them. The fin assembly and the base tube together form an H-shaped cross-section along the radial direction of the base tube. T-cell structures are provided on the base tube of the finned tube bundle. Vortex generators are respectively installed on two fins on the windward and leeward sides of the base tube. The T-cells on the base tube are pits, with the ratio of the T-cell diameter d to the base tube diameter D being 1 / 30 to 1 / 10, the ratio of the T-cell depth h to the base tube diameter D being 1 / 50 to 1 / 25, the included angle β of the T-cells on the circumference of the base tube being 10 to 30°, and the ratio of the T-cell spacing t along the axis of the base tube to the base tube diameter D being 1 / 10 to 1 / 5. Although this heat exchanger structure can alleviate dust accumulation, it cannot completely eliminate the dust accumulation problem on the leeward side or in complex flow field regions.

[0031] In summary, to solve the problem of severe ash accumulation in flue gas heat exchangers under complex operating conditions, it is necessary to develop a flue gas heat exchanger that prevents ash accumulation.

[0032] This utility model provides a flue gas heat exchanger that prevents ash accumulation. The flue gas heat exchanger includes a shell and a heat exchange tube disposed in the shell. The heat exchange tube is connected to a heat exchange medium supply device. The heat exchange tube is a twisted tube. The twisted tube includes twisted plates and a base tube. The twisted plates have a spiral structure.

[0033] In some embodiments, the twisted tubes are arranged in a staggered pattern in the flue gas heat exchanger.

[0034] In some embodiments, the twisted tubes in the flue gas heat exchanger are arranged in a straight line.

[0035] In some embodiments, the flue gas heat exchanger includes at least two of the twisted-blade tubes.

[0036] In some embodiments, the twisted piece includes a first twisted piece and a second twisted piece respectively disposed on both sides of the base tube; and the first twisted piece and the second twisted piece are symmetrically distributed along the base tube.

[0037] In some embodiments, the twisted piece includes at least two first twisted pieces, the distance between the first twisted pieces is 80 to 120 mm, and the helix angle θ of the twisted piece is in the range of 0° < θ ≤ 180°.

[0038] This invention improves the structure of the flue gas heat exchanger to obtain a twisted-fin tube type flue gas heat exchanger. The twisted-fin tube type heat exchanger can enhance the disturbance of flue gas outside the tube, form a turbulence effect, and improve the heat exchange efficiency; it can also change the local flue gas flow direction, dynamically scour the airflow, prevent ash deposition and bridging in the flue gas, and increase the service life of the flue gas heat exchanger.

[0039] The following description is based on specific examples:

[0040] Example 1

[0041] This embodiment provides a flue gas heat exchanger that prevents ash accumulation. The left view and front view of the flue gas heat exchanger are shown below. Figure 1 and Figure 2 As shown, the flue gas heat exchanger includes a shell 3 and heat exchange tubes disposed within the shell, the pipes of which are connected to a heat exchange medium supply device 4; the flue gas heat exchanger also includes a flue gas inlet 2, a flue gas outlet 5, and an ash hopper 6; the heat exchange tubes are twisted fin tubes 1; the flue gas heat exchanger includes 50 of the twisted fin tubes 1, such as... Figure 3 As shown, the twisted tubes 1 are arranged in a staggered pattern in the flue gas heat exchanger. Each twisted tube 1 includes a twisted plate 101 and a base tube 102. The twisted plate 101 has a helical structure, and the helical angle θ of the twisted plate 101 is 90°. Figure 4 As shown, the twisted piece 101 includes 100 first twisted pieces 1011 and 100 second twisted pieces 1012; the first twisted pieces 1011 and the second twisted pieces 1012 are symmetrically distributed on both sides of the base tube 102; the distance between the first twisted pieces 1011 is 100mm.

[0042] Example 2

[0043] This embodiment provides a flue gas heat exchanger for preventing ash accumulation. The flue gas heat exchanger includes a shell and heat exchange tubes disposed within the shell. The pipes of the heat exchange tubes are connected to a heat exchange medium supply device. The flue gas heat exchanger also includes a flue gas inlet, a flue gas outlet, and an ash hopper. The heat exchange tubes are twisted-fin tubes. The flue gas heat exchanger includes 100 of the twisted-fin tubes, such as... Figure 5As shown, the twisted tubes in the flue gas heat exchanger are arranged in a straight line. Each twisted tube includes twisted blades and a base tube. The twisted blades have a spiral structure with a spiral angle θ = 10°. Each twisted blade includes 200 first twisted blades and 200 second twisted blades. The first and second twisted blades are symmetrically distributed on both sides of the base tube. The distance between the first twisted blades is 80 mm.

[0044] Example 3

[0045] This embodiment provides a flue gas heat exchanger for preventing ash accumulation. The flue gas heat exchanger includes a shell and heat exchange tubes disposed within the shell. The heat exchange tubes are connected to a heat exchange medium supply device. The flue gas heat exchanger also includes a flue gas inlet, a flue gas outlet, and an ash hopper. The heat exchange tubes are twisted-blade tubes. The flue gas heat exchanger includes 200 twisted-blade tubes, which are arranged in a staggered pattern. Each twisted-blade tube includes twisted blades and a base tube. The twisted blades have a helical structure with a helical angle θ = 180°. Each twisted blade includes 50 first twisted blades and 50 second twisted blades. The first and second twisted blades are symmetrically distributed on both sides of the base tube. The distance between the first twisted blades is 120 mm.

[0046] Example 4

[0047] This embodiment provides a flue gas heat exchanger that prevents ash accumulation. The only difference from Embodiment 1 is that the distance between the first twisted plates is adjusted from 100mm to 50mm, while the rest is the same as Embodiment 1.

[0048] Example 5

[0049] This embodiment provides a flue gas heat exchanger that prevents ash accumulation. The only difference from Embodiment 1 is that the distance between the first twisted plates is adjusted from 100mm to 150mm, while the rest is the same as Embodiment 1.

[0050] Comparative Example 1

[0051] This comparative example provides a flue gas heat exchanger that prevents ash accumulation. The only difference from Example 1 is that the twisted tube inside the flue gas heat exchanger does not include twisted tubes, that is, the twisted tube inside the flue gas heat exchanger is only a base tube. All other aspects are the same as in Example 1.

[0052] Comparative Example 2

[0053] This comparative example provides a flue gas heat exchanger that prevents ash accumulation. The only difference from Example 1 is that the twisted finned tubes in the flue gas heat exchanger are replaced with 50 staggered finned tube groups. The finned tube group includes 100 quadrilateral fins located on both sides of a base tube, with a distance of 100mm between two adjacent fins on the same side. All other aspects are the same as in Example 1.

[0054] Sintering raw materials including iron ore, limestone, and coke were sintered at 1300℃ for 8 hours to obtain blocky sintered clinker at 800℃ and flue gas at 250℃. The flue gas was then passed through the flue gas heat exchangers of Examples 1-5 and Comparative Examples 1-2 of this utility model for heat exchange, and the service life of the flue gas heat exchangers was evaluated. When the sensible heat recovery efficiency of the flue gas decreased to 80% of the initial sensible heat recovery efficiency, the twisted tubes in the flue gas heat exchanger needed to be replaced. The service life of the twisted tubes at this time is the service life of the flue gas heat exchanger.

[0055] (1) By improving the structure of the flue gas heat exchanger, this utility model obtains a twisted tube flue gas heat exchanger. The twisted tube heat exchanger can enhance the disturbance of flue gas outside the tube, form a turbulence effect, and improve the heat exchange efficiency. It can also change the local flue gas flow direction, dynamically scour the airflow, prevent ash in the flue gas from bridging, and increase the service life of the flue gas heat exchanger.

[0056] (2) By further optimizing the structure of the twisted tube, the present invention enables the flue gas to generate centrifugal force when passing through the twisted tube, so that the dust in the flue gas is thrown outward. The dust particles are not easy to adhere to the surface of the twisted tube and are more likely to fall off under the action of vibration or wind, which can prevent the dust from bridging and causing blockage in the twisted tube. At the same time, the flue gas can flow turbulently between the twisted tubes, which enhances the heat exchange efficiency. It also reduces the local scouring of the tube wall by the flue gas and increases the service life of the flue gas heat exchanger.

[0057] In summary, this utility model improves the structure of the flue gas heat exchanger to obtain a twisted-fin tube type flue gas heat exchanger. The twisted-fin tube type heat exchanger can enhance the disturbance of flue gas outside the tube, form a turbulence effect, and improve the heat exchange efficiency; it can also change the local flue gas flow direction, dynamically scour the airflow, prevent ash deposition and bridging in the flue gas, and increase the service life of the flue gas heat exchanger.

[0058] The applicant declares that the above description is only a specific embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present utility model fall within the protection and disclosure scope of the present utility model.

Claims

1. A flue gas heat exchanger that prevents ash accumulation, characterized in that, The flue gas heat exchanger includes a shell and heat exchange tubes disposed within the shell, wherein the pipes of the heat exchange tubes are connected to a heat exchange medium supply device. The heat exchange tube is a twisted-plate tube; the twisted-plate tube includes twisted plates and a base tube, and the twisted plates have a spiral structure.

2. The flue gas heat exchanger for preventing ash accumulation according to claim 1, characterized in that, The twisted tubes are arranged in a staggered pattern in the flue gas heat exchanger.

3. The flue gas heat exchanger for preventing ash accumulation according to claim 1, characterized in that, The twisted tubes are arranged in a straight line in the flue gas heat exchanger.

4. The flue gas heat exchanger for preventing ash accumulation according to claim 2 or 3, characterized in that, The flue gas heat exchanger includes at least two of the aforementioned twisted-blade tubes.

5. The flue gas heat exchanger for preventing ash accumulation according to claim 1, characterized in that, The twisted plate includes a first twisted plate and a second twisted plate respectively disposed on both sides of the base tube.

6. The flue gas heat exchanger for preventing ash accumulation according to claim 5, characterized in that, The first twisted piece and the second twisted piece are symmetrically distributed along the base tube.

7. The flue gas heat exchanger for preventing ash accumulation according to claim 5, characterized in that, The twisted piece includes at least two of the first twisted pieces.

8. The flue gas heat exchanger for preventing ash accumulation according to claim 5, characterized in that, The distance between the first twisted pieces is 80-120 mm.

9. The flue gas heat exchanger for preventing ash accumulation according to claim 1, characterized in that, The range of the helical angle θ of the twisted piece is 0°<θ≤180°.

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