Annealing furnace with flue gas waste heat recycling

Abstract

The utility model relates to annealing furnace technical field discloses a kind of annealing furnaces of flue gas waste heat recycling, including furnace body, heating device, workpiece placement area and flue gas outlet, further including waste heat recovery device, the waste heat recovery device includes heat exchanger, circulating pipeline and fan, the heat exchanger is connected with the flue gas outlet by the circulating pipeline, for the flue gas heat generated by the annealing furnace is transferred to medium, the circulating pipeline is provided with the fan, for driving medium flow in the circulating pipeline, the waste heat recovery device further includes preheating zone, the preheating zone is connected with the heat exchanger by the circulating pipeline.In the utility model, the cooperation of plate heat exchanger and preheating zone flow guide air duct, the high-temperature flue gas heat of annealing furnace is transferred to circulating air, and hot air circulation preheating workpiece is formed by frequency conversion fan driving, so that workpiece is heated in advance before furnace, reduce heating device energy consumption, shorten annealing time, significantly improve energy utilization efficiency.

Description

Technical Field

[0001] This utility model belongs to the field of annealing furnace technology, and in particular relates to an annealing furnace for recovering and utilizing waste heat from flue gas. Background Technology

[0002] An annealing furnace is a device used to heat metallic materials to achieve specific mechanical properties. By heating and maintaining a certain temperature, the annealing furnace can alter the microstructure of the metallic material, thereby improving its machinability, strength, toughness, and other properties. During the annealing process, the control of furnace temperature and time is crucial to the quality of the final product.

[0003] Traditional annealing furnaces typically consist of several main components, including a heating system, a temperature control system, an exhaust system, and a furnace body structure. The heating system provides heat through combustion energy, the temperature control system monitors and regulates the temperature inside the furnace to ensure a stable annealing process, and the exhaust system is used to remove waste gases and excess heat from the furnace. The furnace body structure ensures temperature uniformity within the furnace and bears the physical load throughout the heating process.

[0004] The low waste heat recovery efficiency of traditional annealing furnaces is mainly due to the fact that most of the heat is lost through the exhaust system or furnace walls, without being effectively recovered and utilized. This heat loss not only increases energy consumption but also exacerbates environmental pollution. Inefficient waste heat recovery results in low energy utilization, high operating costs, and an unnecessary burden on the environment. Utility Model Content

[0005] To overcome the above shortcomings, this utility model provides an annealing furnace for recovering and utilizing waste heat from flue gas, aiming to improve the problems of low waste heat recovery efficiency of traditional annealing furnaces, resulting in low energy utilization, high operating costs, and unnecessary burden on the environment.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: an annealing furnace for recovering and utilizing waste heat from flue gas, comprising a furnace body, a heating device, a workpiece placement area and a flue gas outlet, and further comprising a waste heat recovery device, wherein the waste heat recovery device comprises a heat exchanger, a circulation pipe and a fan;

[0007] The heat exchanger is connected to the flue gas outlet through the circulation pipe and is used to transfer the heat of the flue gas generated by the annealing furnace to the medium.

[0008] The fan is installed on the circulation pipeline to drive the medium to flow in the circulation pipeline.

[0009] The waste heat recovery device also includes a preheating zone, which is connected to the heat exchanger via the circulation pipe and is used to receive the medium heated by the heat exchanger to preheat the workpiece to be processed.

[0010] As a further description of the above technical solution:

[0011] The preheating zone is located at the front end of the workpiece placement area, and the preheating zone is provided with multiple air guide ducts, which are connected to the circulation pipe to form a hot air circulation.

[0012] As a further description of the above technical solution:

[0013] The heat exchanger is a plate heat exchanger, and the ratio of its heat exchange area to the cross-sectional area of ​​the flue gas outlet is 2:1.

[0014] As a further description of the above technical solution:

[0015] The medium is air, and the circulation pipeline is provided with a medium inlet and a medium outlet for replenishing and replacing the medium.

[0016] As a further description of the above technical solution:

[0017] The circulation pipeline is also equipped with a temperature sensor and a flow regulating valve. The temperature sensor is electrically connected to the flow regulating valve to achieve closed-loop temperature control of the preheating zone.

[0018] As a further description of the above technical solution:

[0019] The fan is a variable frequency speed control fan, and its installation position is close to the flue gas inlet end of the heat exchanger to enhance the circulation power of the medium.

[0020] As a further description of the above technical solution:

[0021] The outer surface of the circulation pipe is covered with an insulation layer, which is made of ceramic fiber material.

[0022] As a further description of the above technical solution:

[0023] A filter device is provided between the flue gas outlet and the heat exchanger. The filter device is a metal filter screen used to trap dust particles in the flue gas. The inner wall of the preheating zone is coated with a ceramic coating to resist long-term erosion by the high-temperature medium.

[0024] This utility model has the following beneficial effects:

[0025] 1. In this utility model, the plate heat exchanger and the preheating zone air duct work together to transfer the heat of the high-temperature flue gas from the annealing furnace to the circulating air. Driven by a variable frequency fan, the hot air circulation preheats the workpiece, so that the workpiece is preheated before entering the furnace, reducing the energy consumption of the heating device, shortening the annealing time, and significantly improving energy utilization efficiency.

[0026] 2. In this utility model, the temperature sensor and flow regulating valve achieve precise temperature control of the preheating zone, the ceramic fiber insulation layer reduces heat loss, the metal filter screen prevents heat exchanger blockage, and the ceramic coating enhances the durability of the preheating zone. The whole device has a compact structure and stable operation, which reduces equipment maintenance costs and can be directly adapted to existing annealing furnaces. It improves production efficiency while reducing pollutant emissions, thus achieving both economic and environmental benefits. Attached Figure Description

[0027] Figure 1 This is a perspective view of an annealing furnace for recovering and utilizing waste heat from flue gas, as proposed in this utility model.

[0028] Figure 2 This is a schematic diagram of the furnace body structure of an annealing furnace for recovering and utilizing waste heat from flue gas, as proposed in this utility model.

[0029] Figure 3 This is a schematic diagram of the preheating zone structure of an annealing furnace for recovering and utilizing waste heat from flue gas, as proposed in this utility model.

[0030] Figure 4 This is a schematic diagram of the heat exchanger structure of an annealing furnace for recovering and utilizing waste heat from flue gas, as proposed in this utility model.

[0031] The names and numbers of the components in the diagram are as follows:

[0032] 1. Furnace body; 2. Heating device; 3. Workpiece placement area; 4. Flue gas outlet; 5. Heat exchanger; 6. Circulation pipeline; 7. Fan; 8. Preheating zone; 9. Guide air duct; 10. Medium inlet; 11. Medium outlet; 12. Temperature sensor; 13. Flow regulating valve; 14. Insulation layer; 15. Filter device. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0034] Reference Figures 1-4 An embodiment of the present invention provides an annealing furnace for recovering and utilizing waste heat from flue gas, comprising a furnace body 1, a heating device 2, a workpiece placement area 3 and a flue gas outlet 4, and further comprising a waste heat recovery device, which includes a heat exchanger 5, a circulation pipe 6 and a fan 7.

[0035] The heat exchanger 5 is connected to the flue gas outlet 4 via the circulation pipe 6, and is used to transfer the heat of the flue gas generated by the annealing furnace to the medium;

[0036] A fan 7 is installed on the circulation pipe 6 to drive the medium to flow in the circulation pipe 6;

[0037] The waste heat recovery device also includes a preheating zone 8, which is connected to a heat exchanger 5 via a circulation pipe 6. The preheating zone 8 receives the medium heated by the heat exchanger 5 to preheat the workpiece to be processed. The preheating zone 8 is located at the front end of the workpiece placement area 3, and it contains multiple guide air ducts 9 connected to the circulation pipe 6 to form a hot air circulation. The heat exchanger 5 is a plate heat exchanger with a heat exchange area to flue gas outlet 4 cross-sectional area ratio of 2:1. The medium is air, and the circulation pipe 6 is equipped with a medium inlet 10 and a medium outlet 11 for replenishing and replacing the medium. The circulation pipe 6 is also equipped with a temperature... Temperature sensor 12 and flow regulating valve 13 are electrically connected to achieve closed-loop temperature control of preheating zone 8. Fan 7 is a variable frequency speed regulating fan, which is installed close to the flue gas inlet end of heat exchanger 5 to enhance the circulation power of the medium. The outer surface of circulation pipe 6 is covered with insulation layer 14, which is made of ceramic fiber material. A filter device 15 is installed between flue gas outlet 4 and heat exchanger 5. The filter device 15 is a metal filter screen used to intercept dust particles in flue gas. The inner wall of preheating zone 8 is coated with ceramic to resist long-term scouring by high temperature medium.

[0038] Working principle: When the annealing furnace is working, the heating device 2 heats the workpieces in the workpiece placement area 3 inside the furnace body 1. The generated high-temperature flue gas is discharged from the flue gas outlet 4 and flows into the plate heat exchanger 5 after being filtered for dust by the metal filter screen 15. The heat exchanger 5 transfers the heat of the flue gas to the air medium in the circulation pipe 6 through the heat exchange area with a cross-sectional area ratio of 2:1 to that of the flue gas outlet 4. The variable frequency speed control fan 7 is installed near the flue gas inlet end of the heat exchanger 5 to drive the air to flow in the circulation pipe 6. The heated air enters the preheating zone 8 set at the front end of the workpiece placement area 3 through the circulation pipe 6. The guide air duct 9 in the preheating zone 8 is connected to the circulation pipe 6. A hot air circulation is formed to uniformly preheat the workpiece to be processed. The temperature sensor 12 on the circulation pipe 6 monitors the air temperature in real time and feeds it back to the flow regulating valve 13. Closed-loop control of the temperature of the preheating zone 8 is achieved through electrical connection. The air medium can be replenished through the medium inlet 10 and replaced through the medium outlet 11 to maintain circulation stability. The ceramic fiber insulation layer 14 on the outer surface of the circulation pipe 6 reduces heat loss. The ceramic coating on the inner wall of the preheating zone 8 resists long-term erosion by high-temperature air. After the preheated workpiece enters the workpiece placement area 3, it is further heated and annealed by the heating device 2, thereby achieving efficient recovery and utilization of waste heat from the flue gas, reducing energy consumption and improving production efficiency.

[0039] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

[0040] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An annealing furnace for recovering waste heat from flue gas, comprising a furnace body (1), a heating device (2), a workpiece placement area (3), and a flue gas outlet (4), characterized in that: It also includes a waste heat recovery device, which includes a heat exchanger (5), a circulation pipe (6) and a fan (7); The heat exchanger (5) is connected to the flue gas outlet (4) through the circulation pipe (6) and is used to transfer the heat of the flue gas generated by the annealing furnace to the medium. The fan (7) is installed on the circulation pipe (6) to drive the medium to flow in the circulation pipe (6); The waste heat recovery device also includes a preheating zone (8), which is connected to the heat exchanger (5) through the circulation pipe (6) and is used to receive the medium heated by the heat exchanger (5) to preheat the workpiece to be processed.

2. The annealing furnace for recovering waste heat from flue gas according to claim 1, characterized in that: The preheating zone (8) is located at the front end of the workpiece placement area (3), and the preheating zone (8) is provided with a plurality of air ducts (9), which are connected to the circulation pipe (6) to form a hot air circulation.

3. An annealing furnace for recovering waste heat from flue gas according to claim 1, characterized in that: The heat exchanger (5) is a plate heat exchanger, and the ratio of its heat exchange area to the cross-sectional area of ​​the flue gas outlet (4) is 2:

1.

4. An annealing furnace for recovering waste heat from flue gas according to claim 1, characterized in that: The medium is air, and the circulation pipe (6) is provided with a medium inlet (10) and a medium outlet (11) for replenishing and replacing the medium.

5. An annealing furnace for recovering waste heat from flue gas according to claim 1, characterized in that: A temperature sensor (12) and a flow regulating valve (13) are also provided on the circulation pipe (6). The temperature sensor (12) and the flow regulating valve (13) are electrically connected to realize closed-loop temperature control of the preheating zone (8).

6. An annealing furnace for recovering waste heat from flue gas according to claim 1, characterized in that: The fan (7) is a variable frequency speed control fan, and its installation position is close to the flue gas inlet end of the heat exchanger (5) to enhance the circulation power of the medium.

7. An annealing furnace for recovering waste heat from flue gas according to claim 1, characterized in that: The outer surface of the circulation pipe (6) is covered with a heat insulation layer (14), which is made of ceramic fiber material.

8. An annealing furnace for recovering waste heat from flue gas according to claim 1, characterized in that: A filter device (15) is provided between the flue gas outlet (4) and the heat exchanger (5). The filter device (15) is a metal filter screen used to trap dust particles in the flue gas. The inner wall of the preheating zone (8) is coated with a ceramic coating to resist long-term scouring by the high-temperature medium.

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