Heat removal device and method for steel rolling cooling bed waste heat recovery

Abstract

The invention relates to the technical field of cooling bed waste heat recovery, in particular to a heat extraction device and method for steel rolling cooling bed waste heat recovery. The heat removal device comprises an outer cover body and a heat exchange set. The outer cover body comprises a supporting plate, a baffle and a top plate, the supporting plate and the baffle form a peripheral structure, and the top plate is located at the top of the peripheral structure; the supporting plates are located on the two opposite sides of the peripheral structure and comprise the upper supporting plate and the lower supporting plate, and the upper supporting plate and the lower supporting plate are detachably connected. The heat exchange sets at least comprise three layers of structures, the top layer heat exchange set and the middle layer heat exchange set are installed on the upper supporting plate, the bottom layer heat exchange set is installed on the lower supporting plate, and one end of the bottom layer heat exchange set is connected in series through a plurality of bent pipes. The problem that an existing heat removal device is inconvenient to maintain is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of waste heat recovery of cooling beds, and in particular to a heat extraction device and method for recovering waste heat of a steel rolling cooling bed. Background Art

[0002] In the steel manufacturing process, the steel rolling cooling bed is a key equipment for cooling high-temperature steel. The steel is cooled from 950℃ to below 200℃ on the cooling bed. A large amount of heat released in this process is usually directly discharged into the air, resulting in energy waste, deterioration of the working environment and environmental pollution. According to statistics, on average, each hot-rolled steel line can recycle about 80,000 tons of 0.5MPa saturated steam per year, and 1 ton of 0.5MPa saturated steam can generate 110 kWh of electricity, which can generate about 8.8 million KWh per year and reduce carbon dioxide emissions by 8,800 tons per year. If all the more than 2,000 hot-rolled cooling beds in the country adopt this device, steam can be recycled to generate 17.6 billion KWh per year, which can reduce carbon dioxide emissions by 17.6 million tons per year. Therefore, developing an efficient heat extraction device to recover this waste heat and convert it into usable energy is of great significance to improving energy efficiency and reducing environmental pollution.

[0003] At present, the waste heat recovery of the steel rolling cooling bed is mainly carried out through the heat exchange tubes of the heat extraction device. The heat exchange pipes of the heat extraction device are generally arranged in multiple layers, and the gaps between the multiple layers of heat exchange groups are small. The heat exchange tubes on the top or bottom layer can be easily maintained, but when the heat exchange tubes in the middle layer have problems, they are difficult to repair, increasing the maintenance cost. In addition, the heat extraction device exchanges heat through the water medium inside the heat exchange tube, but because the water medium inside the heat exchange tube is usually in a laminar state, it leads to uneven heating and slow flow rate.

[0004] Based on the existing technology, the following main technical problems can be analyzed:

[0005] 1. The upper and lower layer structures of the heat exchange tubes are not conducive to maintenance, especially the middle layer heat exchange group, which increases the maintenance cost.

[0006] 2. The laminar flow state of the water medium inside the heat exchange tube leads to uneven heating and slow flow rate, resulting in low heat transfer efficiency. Summary of the invention

[0007] In view of the deficiencies in the prior art, an embodiment of the present invention aims to provide a heat extraction device for recovering waste heat from a steel rolling cooling bed, so as to solve the problems of inconvenient maintenance of the existing heat extraction devices.

[0008] In order to achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0009] A heat extraction device for recovering waste heat from a steel rolling cooling bed, comprising: an outer cover body and a heat exchange group; the outer cover body comprises a support plate, a baffle plate and a top plate, the support plate and the baffle plate form a peripheral structure, the top plate is located on the top of the peripheral structure; the support plates are located on opposite sides of the peripheral structure, the support plates comprise a support upper plate and a support lower plate, the support upper plate and the support lower plate are detachably connected; the heat exchange group comprises at least a three-layer structure, a top layer heat exchange group and a middle layer heat exchange group are mounted on the support upper plate, a bottom layer heat exchange group is mounted on the support lower plate, and one end of the bottom layer heat exchange group is connected in series through a plurality of elbows.

[0010] Optionally, the top plate is a patterned steel plate, and is also provided with lifting ears for lifting.

[0011] Optionally, an axial flow fan is also provided on the top plate, and the peripheral structure is divided into a plurality of areas, with an axial flow fan installed in each area.

[0012] Optionally, the heat exchange group has three layers, and two adjacent layers of heat exchange groups are connected in series. The top layer of heat exchange group is provided with a water inlet main pipe, and the bottom layer of heat exchange group is provided with a water inlet outlet.

[0013] Optionally, in the three-layer heat exchange group, the bottom layer heat exchange group and the middle layer heat exchange group are detachably connected.

[0014] Optionally, the bottom heat exchange group includes a plurality of heat exchange tubes arranged in parallel, the axis of the heat exchange tubes is perpendicular to the support plate, one end of the heat exchange tubes is connected through a collecting pipe, a partition is provided in the collecting pipe, the partition divides the collecting pipe into a plurality of areas, and the other ends of the heat exchange tubes in adjacent areas are connected through a bend pipe.

[0015] Optionally, the inner walls of the heat exchange tubes of the top layer heat exchange group and the middle layer heat exchange group are provided with spoilers, the spoilers are arranged in a spiral manner around the axis of the heat exchange tubes, and the outer walls of the heat exchange tubes are provided with spiral fins.

[0016] Optionally, the outer walls of the heat exchange tubes of the top layer heat exchange group and the middle layer heat exchange group are provided with spiral fins.

[0017] Optionally, the cross-section of the heat exchange tubes of the bottom heat exchange group is elliptical.

[0018] The embodiment of the present invention further provides a heat extraction method of the heat extraction device for recovering waste heat from a steel rolling cooling bed as described above, comprising:

[0019] The heat absorbing medium enters from the top heat exchange group, passes through the middle heat exchange group, enters the bottom heat exchange group, and flows out from the bottom heat exchange group;

[0020] Among them, the heat absorbing medium performs convection heat replacement in the top heat exchange group to complete preheating, performs radiation heat replacement and convection heat replacement in the middle heat exchange group, and performs radiation heat replacement in the bottom heat exchange group.

[0021] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0022] When the heat exchange tube of the middle heat exchange group of the heat extraction device fails, the upper support plate and the lower support plate can be separated, and the lower support plate can be pulled out from the side with the bottom heat exchange group as a whole, and then the middle heat exchange group can be repaired from the bottom, which is convenient for the inspection of the middle heat exchange group and saves maintenance costs; and if the bottom heat exchange group fails, it is more convenient to repair it by pulling it out. One end of the bottom heat exchange group is connected in series through multiple curved pipes. This design enables a good fluid channel to be formed between the heat exchange groups on each layer to improve the heat exchange efficiency, and avoids the problem of obstruction when pulling out the bottom heat exchange group.

[0023] Advantages of additional aspects of the present invention will be given in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In addition, the spacing or size between each other is exaggerated to show the position of each part, and the schematic diagram is only used for illustration.

[0025] Figure 1 is a schematic cross-sectional view of a heat exchange device provided by an embodiment of the present invention, perpendicular to the direction of the heat exchange tube;

[0026] Figure 2 is a schematic diagram of a support plate provided by an embodiment of the present invention;

[0027] Figure 3 is a top view provided by an embodiment of the present invention;

[0028] Figure 4 is a schematic cross-sectional view of a heat exchange device provided by an embodiment of the present invention, parallel to the direction of the heat exchange tube;

[0029] Figure 5 is a schematic diagram of the interior of a heat exchange tube provided by an embodiment of the present invention;

[0030] In the figure: 1, outer cover; 11, baffle; 12, support plate; 121, upper support plate; 122, lower support plate; 123, connecting plate; 13, lifting lug; 14, top plate; 2, heat exchange group; 21, collecting pipe; 211, partition; 22, heat exchange tube; 221, spoiler; 23, elbow; 24, water inlet mother pipe; 25, water outlet mother pipe; 3, axial flow fan; DETAILED DESCRIPTION

[0031] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0032] Terminology explanation:

[0033] Laminar flow: refers to the phenomenon that when a fluid flows, each layer of fluid does not mix with each other and the flow is smooth.

[0034] Turbulence: refers to the phenomenon that when a fluid flows, the various layers of the fluid mix violently and the flow state becomes chaotic.

[0035] Heat exchange tube: It is a pipe used to transfer heat, and its internal structure has a direct impact on the heat transfer efficiency.

[0036] In order to solve the technical problems mentioned in the background technology, this embodiment proposes a heat extraction device for recovering waste heat from a steel rolling cooling bed, which improves heat transfer efficiency, reduces energy waste, and reduces maintenance costs.

[0037] like Figure 1 As shown, the heat extraction device includes an outer cover body 1 and a heat exchange group 2; the outer cover body 1 includes a support plate 12, a baffle 11 and a top plate 14, the support plate 12 and the baffle 11 form an outer structure, the support plate 12 and the baffle 11 are enclosed on the column to form a rectangular outer cover body 1, the top plate 14 is located on the top of the outer structure, and the surface of the outer cover body 1 is insulated with aluminum silicate.

[0038] The support plates 12 are located on opposite sides of the peripheral structure, and the support plates 12 include an upper support plate 121 and a lower support plate 122. The upper support plate 121 and the lower support plate 122 are detachably connected, for example, the upper support plate 121 and the lower support plate 122 are connected by connecting plates 123 and connecting bolts (such as Figure 2As shown in the figure, the upper support plate 121 and the lower support plate 122 can be separated by removing the connecting bolts of the two parts. The heat exchange group 2 includes at least a three-layer structure, and the top layer heat exchange group 2 and the middle layer heat exchange group 2 are installed on the upper support plate 121. In order to improve the supporting effect, multiple support plates 12 can also be arranged inside the peripheral structure, and the upper plate and the lower plate of the internal support plate 12 are not connected. The bottom layer heat exchange group 2 is installed on the lower support plate 122, and one end of the bottom layer heat exchange group 2 is connected in series through multiple elbows 23.

[0039] The heat extraction device is composed of an outer cover 1 and a heat exchange group 2. The structure of the outer cover 1 includes a support plate 12, a baffle 11 and a top plate 14, wherein the support plate 12 and the baffle 11 together form a peripheral structure surrounding the internal heat exchange group 2. The support plate 12 is divided into a support upper plate 121 and a support lower plate 122, and the two are detachably connected to facilitate later maintenance and repair. The support upper plate 121 is used to support the top and middle heat exchange groups 2, and the bottom heat exchange group 2 is installed on the support lower plate 122. One end of the bottom heat exchange group 2 is connected in series through a plurality of elbows 23. This design enables a good fluid channel to be formed between each layer of the heat exchange group 2 to improve the heat exchange efficiency, and avoids the problem of obstruction when the bottom heat exchange group 2 is extracted. In the actual working process, the fluid passes through the heat exchange groups 2 of different layers in turn, and the heat exchange effect of each layer of the heat exchange group 2 is used to realize the effective recovery and utilization of heat.

[0040] During maintenance, the top plate 14 is a detachable plate, which is convenient for maintenance of the top heat exchange group 2. The bottom is not closed, so the bottom heat exchange group 2 can be directly maintained. When the heat exchange tube 22 of the middle heat exchange group 2 fails, the upper support plate 121 and the lower support plate 122 can be separated, and the lower support plate 122 can be pulled out from the side with the bottom heat exchange group 2 as a whole, and then the middle heat exchange group 2 can be repaired from the bottom, which is convenient for maintenance of the middle heat exchange group 2 and saves maintenance costs; and if the bottom heat exchange group 2 fails, it can be directly repaired at the bottom, and it can also be repaired more conveniently by pulling it out.

[0041] The supporting upper plate 121 is fixed to the outer channel steel frame by welding to ensure the supporting stability of the heat exchange group 2. The lower part is more stable than the upper part by bolt connection.

[0042] The upper part is fixed and the lower part is detachable. The lower heat exchange group can be pulled out to directly repair the middle heat exchange group. If the lower part is fixed and the upper part is detachable, not only the upper heat exchange group needs to be pulled out, but also the top plate needs to be removed to repair the middle heat exchange group. In addition, the maintenance personnel need to climb up to the top of the heat extraction device to perform maintenance, which increases the risk factor and is cumbersome.

[0043] The top plate 14 is a patterned steel plate, which not only increases the strength and durability of the top plate 14, but also effectively enhances the aesthetics and anti-slip properties of the overall structure, making it convenient for people to access for maintenance. In addition, the lifting lugs 13 provided on the top plate 14 make the device more convenient during installation and maintenance. The lifting lugs 13 provide a variety of lifting methods, which can adapt to the needs of different working environments and ensure the safety and stability of the equipment.

[0044] like Figure 3 , Figure 4 As shown, an axial flow fan 3 is also provided on the top plate 14, and the peripheral structure is divided into multiple areas, each of which is equipped with an axial flow fan 3. The design of providing the axial flow fan 3 on the top plate 14 enables the entire device to more effectively promote air circulation from bottom to top, thereby improving the overall heat exchange efficiency of the heat exchange device.

[0045] The heat exchange group 2 has three layers, and two adjacent layers of heat exchange groups 2 are connected in series. The top layer of heat exchange group 2 is provided with a water inlet main pipe 24, and the bottom layer of heat exchange group 2 is provided with a water inlet outlet. The water inlet main pipe 24 on the top layer of heat exchange group 2 is used to guide the water medium into the top layer of heat exchange group 2. In the top layer of heat exchange group 2, after the water medium undergoes convective heat displacement, it undergoes radiation and convective heat displacement through the middle layer of heat exchange group 2, and finally flows to the bottom layer of heat exchange group 2, and the bottom layer of heat exchange group 2 is used to further recover and utilize heat. Through such a layered design, the heat recovery efficiency can be maximized to ensure full utilization of heat during the cooling process.

[0046] In the three-layer heat exchange group 2, the bottom heat exchange group 2 and the middle heat exchange group 2 are detachably connected. Such a design allows the bottom heat exchange group 2 to be easily disassembled and independently repaired when a failure occurs or maintenance is required without affecting other parts of the overall device. More importantly, the middle heat exchange group 2 can be repaired.

[0047] like Figure 3 As shown, the bottom heat exchange group 2 includes a plurality of heat exchange tubes 22 arranged in parallel, the surface of the heat exchange tubes 22 is coated with a paint material that is resistant to high temperatures and has a high radiation absorption rate, the axis of the heat exchange tubes 22 is perpendicular to the support plate 12, one end of the heat exchange tubes 22 is connected through a manifold 21, and a partition 211 is provided in the manifold 21, the partition 211 divides the manifold 21 into a plurality of areas, and the other ends of the heat exchange tubes 22 in adjacent areas are connected through a bend 23. Figure 3As shown, the first area and the second area on the upper side of the manifold 21 are both connected to 5 heat exchange tubes 22. The left side of the 5 heat exchange tubes 22 in the first area is connected to the first area of ​​the manifold 21, and the right side is connected to the right side of the 5 heat exchange tubes 22 in the second area through the elbow 23. The left side of the 5 heat exchange tubes 22 in the second area is connected to the second area of ​​the manifold 21. Both ends of the other upper heat exchange groups 2 are manifolds 21, and the manifolds 21 of adjacent layers are connected.

[0048] like Figure 5 As shown, the inner wall of the heat exchange tube 22 of the top heat exchange group 2 and the middle heat exchange group 2 is provided with spoilers 221, and the spoilers 221 are arranged in a spiral manner around the axis of the heat exchange tube 22. This design can effectively change the state of fluid flow, making it turbulent, so that the water medium is heated more evenly, the flow rate of the water medium is accelerated, and the contact area between the fluid and the wall of the heat exchange tube 22 is increased, thereby improving the heat exchange efficiency. The outer wall of the heat exchange tube 22 of the top heat exchange group 2 and the middle heat exchange group 2 is provided with spiral fins, which further increases the heat exchange area and enhances the heat exchange effect.

[0049] The cross section of the heat exchange tube 22 of the bottom heat exchange group 2 is elliptical, which helps to increase the heating area. Compared with the circular tube, the heat transfer coefficient of the elliptical tube can be increased by 30%. The elliptical cross section can effectively increase the flow area of ​​the fluid inside the heat exchange tube 22, making the heat transfer more efficient, thereby improving the heat exchange efficiency of the entire heat exchange device, ensuring that a better heat recovery effect can be achieved at the same flow rate.

[0050] The heat extraction method of the heat extraction device:

[0051] The manifold 21 of the lower heat exchange group 2 is connected in series with the manifold 21 of the upper heat exchange group 2 to form a passage, wherein the manifold 21 of the top heat exchange group 2 is provided with a water inlet main pipe 24, and the manifold 21 of the bottom heat exchange group 2 is provided with a water outlet main pipe 25. The water medium enters from the pipe opening of the water inlet main pipe 24 in turn, undergoes convective heat replacement through the top heat exchange group 2, undergoes radiation heat replacement and convective heat replacement when passing through the middle heat exchange group 2, and finally undergoes radiation heat replacement through the bottom heat exchange group 2. After multiple process turns, it flows out from one end of the water outlet main pipe 25 and enters the steam drum. The top layer is used for water inlet, and the top and middle layers are for radiation heat replacement and convective heat replacement. It is preheated first and then flows through the bottom elliptical light pipe to increase the heat exchange area, make the heating uniform, and reduce the heat loss in the process of entering the steam drum. This method ensures that the medium fully utilizes the heat exchange capacity of each layer of the heat exchange group 2 in the whole process, and improves the recovery efficiency of heat energy.

[0052] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A heat extraction device for recovering waste heat from a steel rolling cooling bed, characterized in that: include: Outer cover and heat exchange group; The outer cover body includes a support plate, a baffle plate and a top plate, wherein the support plate and the baffle plate form a peripheral structure, and the top plate is located on the top of the peripheral structure; the support plate is located on two opposite sides of the peripheral structure, and the support plate includes a support upper plate and a support lower plate, and the support upper plate and the support lower plate are detachably connected; The heat exchange group comprises at least a three-layer structure, the top layer heat exchange group and the middle layer heat exchange group are mounted on the upper support plate, the bottom layer heat exchange group is mounted on the lower support plate, and one end of the bottom layer heat exchange group is connected in series through a plurality of elbows.

2. The heat extraction device for recovering waste heat from a steel rolling cooling bed according to claim 1, characterized in that: The top plate is a patterned steel plate and is provided with lifting ears for lifting.

3. The heat extraction device for recovering waste heat from a steel rolling cooling bed according to claim 1, characterized in that: An axial flow fan is also arranged on the top plate, and the peripheral structure is divided into a plurality of areas, each of which is equipped with an axial flow fan.

4. The heat extraction device for recovering waste heat from a steel rolling cooling bed according to claim 1, characterized in that: The heat exchange group has three layers, and two adjacent layers of heat exchange groups are connected in series. The top layer of heat exchange group is provided with a water inlet main pipe, and the bottom layer of heat exchange group is provided with a water inlet outlet.

5. The heat extraction device for recovering waste heat from a steel rolling cooling bed according to claim 4, characterized in that: In the three-layer heat exchange group, the bottom layer heat exchange group and the middle layer heat exchange group are detachably connected.

6. The heat extraction device for recovering waste heat from a steel rolling cooling bed according to claim 5, characterized in that: The bottom heat exchange group includes a plurality of heat exchange tubes arranged in parallel, the axis of the heat exchange tubes is perpendicular to the support plate, one end of the heat exchange tubes is connected through a collecting pipe, a partition is provided in the collecting pipe, the partition divides the collecting pipe into a plurality of areas, and the other ends of the heat exchange tubes in adjacent areas are connected through a bend pipe.

7. The heat extraction device for recovering waste heat from a steel rolling cooling bed according to claim 1, characterized in that: The inner walls of the heat exchange tubes of the top layer heat exchange group and the middle layer heat exchange group are provided with spoilers, which are arranged in a spiral manner around the axis of the heat exchange tubes, and the outer walls of the heat exchange tubes are provided with spiral fins.

8. The heat extraction device for recovering waste heat from a steel rolling cooling bed according to claim 7, characterized in that: The outer walls of the heat exchange tubes of the top layer heat exchange group and the middle layer heat exchange group are provided with spiral fins.

9. The heat extraction device for recovering waste heat from a steel rolling cooling bed according to claim 1, characterized in that: The cross section of the heat exchange tubes of the bottom heat exchange group is elliptical.

10. A heat extraction method for a heat extraction device for recovering waste heat from a steel rolling cooling bed as claimed in any one of claims 1 to 9, characterized in that: include: The heat absorbing medium enters from the top heat exchange group, passes through the middle heat exchange group, enters the bottom heat exchange group, and flows out from the bottom heat exchange group; Among them, the heat absorbing medium performs convection heat replacement in the top heat exchange group to complete preheating, performs radiation heat replacement and convection heat replacement in the middle heat exchange group, and performs radiation heat replacement in the bottom heat exchange group.

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