Waste heat recovery device for quick cooling furnace box of heat treatment furnace for cold-rolled silicon steel sheets of motors

Abstract

The present invention discloses a quick cooling furnace box waste heat recovery device for a heat treatment furnace for cold-rolled silicon steel sheets of a motor, which includes a furnace box and a heat collecting cover arranged front and back, a connection end plate fixedly arranged at the front port of the furnace box and a rear port connected to the heat collecting cover, a serpentine heat exchange coil is arranged in the heat collecting cover, and a rectangular heat exchange coil is arranged in the furnace box, the two pipes are connected, and the two pipes respectively have an infusion pipe port and a liquid outlet pipe port for liquid heat exchange medium to enter and discharge, the infusion pipe port and the liquid outlet pipe port are located outside the heat collecting cover and outside the furnace box, and the liquid outlet pipe port is externally connected to a heat storage container. With the above scheme, the liquid heat exchange medium flows through the serpentine heat exchange coil through the infusion pipe port, and heat exchanges with the heat in the heat collecting cover. When the liquid heat exchange medium flows through the rectangular heat exchange coil, it heat exchanges with the high-temperature waste heat in the furnace box, greatly reducing the high-temperature waste heat from the furnace box to the heat collecting cover, and weakening the high-temperature waste heat from the exhaust port at the top of the heat collecting cover to the external environment. As the heat exchange continues, the high-temperature waste heat is effectively recovered.

Description

[Technical field]

[0001] The invention relates to the field of heat treatment equipment for cold-rolled silicon steel sheets for motors, and in particular to a waste heat recovery device for a quick cooling furnace box of a heat treatment furnace for cold-rolled silicon steel sheets for motors. [Background technology]

[0002] The heat treatment furnace is used for degreasing, annealing and bluing of motor rotor punching workpieces and / or stator punching workpieces (hereinafter referred to as workpieces). The heat treatment furnace has multiple functional furnace box areas, namely, degreasing area, annealing area, slow cooling area, bluing area, indirect fast cooling area and direct air cooling area (the workpieces at the unloading station are cooled to room temperature). The purpose of the bluing treatment of the workpiece is to ensure that the anti-rust period meets the expected design requirements of the process and the iron loss of the workpiece is uniform. During the bluing treatment, the workpiece located in the bluing furnace box is subjected to 480℃ high-temperature heat radiation from the radiation tube and sprayed with high-pressure steam medium. The treated workpiece is continuously removed from the bluing furnace box in real time and enters the fast cooling furnace box.

[0003] After bluing, the workpiece enters the rapid cooling stage. The workpiece needs to be quickly cooled from a high temperature of 480°C to about 150°C in the rapid cooling furnace box before it can be taken out of the furnace. This requires indirect cooling of the workpiece and timely discharge of the high-temperature exhaust gas to the outside of the rapid cooling furnace box. A water barrier is usually used to isolate the workpiece from the workpiece, otherwise condensation will occur on the surface of the workpiece, affecting the stability of the bluing quality.

[0004] Therefore, the rapid cooling furnace box is usually designed into two interconnected sections, namely the rapid cooling section of the rapid cooling furnace box with a water barrier and the exhaust section of the high-temperature exhaust gas heat collection hood of the rapid cooling furnace box. Circulating cooling water continuously flows through the water barrier to remove the heat in the furnace box, while the remaining large amount of heat flows through the exhaust section of the high-temperature exhaust gas fume collection hood and is discharged from the exhaust port at the top.

[0005] In order to reduce energy waste, how to collect these large amounts of high-temperature exhaust gases that are directly discharged into the ambient air so that the rapid cooling furnace box of the heat treatment furnace does not emit high-temperature waste heat during the rapid cooling process is an important issue that motor manufacturers must consider. [Summary of the invention]

[0006] In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides a waste heat recovery device for a rapid cooling furnace box of a motor cold-rolled silicon steel sheet heat treatment furnace, which can solve the problem of waste of high-temperature waste heat emission from the rapid cooling furnace box and improve the heat energy resource recovery rate of the rapid cooling furnace box.

[0007] To this end, the present invention provides the following technical solutions:

[0008] A waste heat recovery device for a quick cooling furnace box of a heat treatment furnace for cold-rolled silicon steel sheets of a motor comprises a furnace box body and a heat collecting hood arranged in front and behind, a connecting end plate is fixedly arranged at the front port of the furnace box body and a rear port thereof is connected to the heat collecting hood, a serpentine heat exchange coil is arranged in the heat collecting hood, a rectangular heat exchange coil is arranged in the furnace box body along the longitudinal direction thereof, the serpentine heat exchange coil is connected with the rectangular heat exchange coil, the serpentine heat exchange coil has an infusion pipe port for the introduction of liquid heat exchange medium, the infusion pipe port is located outside the heat collecting hood, the rectangular heat exchange coil has a liquid outlet pipe port for the discharge of liquid heat exchange medium, the liquid outlet pipe port is located outside the furnace box body, and the liquid outlet pipe port is externally connected to a heat storage container.

[0009] In order to realize countercurrent heat exchange of liquid heat exchange medium, the temperature in the heat collecting cover space is lower than the temperature in the furnace box space; the serpentine heat exchange coil is set at a higher position than the rectangular heat exchange coil, and the two are connected by a transition pipe section.

[0010] In order to reduce the heat leakage of the furnace box and improve the working environment temperature around the furnace box, an insulating layer is provided between the furnace shell and the furnace inner shell of the furnace box.

[0011] The staggered bending parts of the serpentine heat exchange coil are respectively fixed on the inner walls of the upper part of the heat collecting cover; the rectangular heat exchange coil is fixed on the furnace inner tank.

[0012] The furnace box is fixed on a frame, which is provided with a plurality of rollers for supporting a conveyor belt, which are adjacent to each other, parallel to each other and rotate in the same direction. The two ends of each roller pass through the furnace box and are laterally supported on the frame. The conveyor belt is located in the furnace inner tank and is movably supported on the rollers.

[0013] The above-mentioned liquid heat exchange medium is liquid molten salt.

[0014] Molten salt has low viscosity, high melting point and good fluidity. The flow process of liquid molten salt in serpentine heat exchange coils and rectangular heat exchange coils is accompanied by a strong heat exchange effect. By recovering heat energy through heat exchange of high-temperature waste heat from the rapid cooling furnace box, it can reduce heat energy waste and provide an excellent industrial solution for the motor manufacturing industry to achieve green production and low-energy production.

[0015] The present invention has the following advantages and positive effects:

[0016] Abandoning the water-proof box and circulating cooling water of the traditional fast cooling furnace box, a rectangular heat exchange coil is added to the furnace box, and a serpentine heat exchange coil is added to the heat collecting cover. The countercurrent heat exchange is adopted. When the liquid heat exchange medium flows through the serpentine heat exchange coil through the infusion pipe, it first exchanges heat with the heat in the heat collecting cover. When the heated liquid heat exchange medium continues to flow through the rectangular heat exchange coil, it exchanges heat with the high-temperature waste heat filled in the furnace box. This greatly reduces the high-temperature waste heat from the furnace box to the heat collecting cover, and reduces the high-temperature waste heat from the exhaust port at the top of the heat collecting cover to the external environment. As the heat exchange continues, the high-temperature liquid heat exchange medium is continuously collected from the liquid outlet to the heat storage container, thereby realizing that the fast cooling furnace box of the heat treatment furnace does not emit high-temperature waste heat during the rapid cooling process, so that these high-temperature waste heat are no longer wasted innocently but are effectively recovered.

Brief Description of the Drawings

[0017] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0018] Figure 1 It is a schematic diagram of the structure of the present invention;

[0019] Figure 2 is along Figure 1 Cross-sectional view of CC. [Specific implementation method]

[0020] Reference Figure 1 , 2 As shown, the waste heat recovery device of the rapid cooling furnace box of the heat treatment furnace for cold-rolled silicon steel sheets of the motor comprises a furnace box body 1 and a heat collecting cover 3 arranged in front and behind, the furnace box body 1 is fixedly provided with a connecting end plate 2 at its front port and its rear port is connected with the front end lower part of the heat collecting cover 3, a serpentine heat exchange coil 41 is arranged in the heat collecting cover 3, and a rectangular heat exchange coil 42 is arranged in the furnace box body 1 along its depth direction, the serpentine heat exchange coil 41 is connected with the rectangular heat exchange coil 42, the serpentine heat exchange coil 41 has an infusion pipe port 410 for the liquid heat exchange medium to pass through, and the infusion pipe port 410 is located outside the heat collecting cover 3, and the rectangular heat exchange coil 42 has a liquid outlet pipe port 420 for the liquid heat exchange medium to be discharged, and the liquid outlet pipe port 420 is located outside the furnace box body 1, and the liquid outlet pipe port 420 is externally connected to a heat storage container (not shown).

[0021] The cross section of the furnace box is rectangular, and the furnace box has a certain depth.

[0022] The temperature in the heat collecting hood space is lower than the temperature in the furnace box space; the serpentine heat exchange coil 41 is arranged at a higher position than the rectangular heat exchange coil 42 , and the two are connected through the transition pipe section 40 .

[0023] In this embodiment, the serpentine heat exchange coil 41, the transition pipe section 40 and the rectangular heat exchange coil are all made of seamless steel pipes.

[0024] An insulating layer 10 is arranged between the furnace shell 11 and the furnace inner container 12 of the furnace box body 1, so the furnace box body is composed of the furnace shell, the insulating layer and the furnace inner container, and the material of the insulating layer is rock wool.

[0025] The serpentine heat exchange coil 41 is fixed at the offset bent parts on the opposite side inner walls of the upper part of the heat collecting cover 3; the rectangular heat exchange coil 42 is fixed on the furnace inner tank 12 after passing through the furnace shell 11 and the insulation layer 10.

[0026] The furnace box 1 is fixed on the frame 5, and the frame 5 is provided with a plurality of rollers 6 which are adjacent to each other, parallel to each other and rotate in the same direction for supporting the conveyor belt 7. The two ends of each roller 6 pass through the furnace box 1 and the roller 6 is laterally supported on the frame 5. The conveyor belt 7 is located in the furnace inner tank 12 and is movably supported on the roller 6.

[0027] The furnace box 1 is connected to the preceding bluing furnace box (known structure not shown) by connecting the end plate 2 and the adapter tube of the existing structure; after the bluing furnace box is removed, the workpieces entering the rapid furnace box online are no longer heated. Figure 2 As shown, I is the workpiece feeding direction, that is, the traveling direction of the conveyor belt (known part).

[0028] Since the high-temperature conveyor mesh belt moving through the rapid cooling furnace box, i.e., the furnace box body 1, no longer needs to heat the workpiece, the rectangular heat exchange coil fixed at the furnace inner tank also absorbs and utilizes the waste heat of the conveyor mesh belt.

[0029] The liquid heat exchange medium is liquid molten salt.

[0030] Molten salt is commercially available.

[0031] Mixed molten salt is a mixture of potassium nitrate (KNO3), sodium nitrite (NaNO2) and sodium nitrate (NaNO3). The powdered molten salt is heated to a melting point of 142°C or above, so that it can be recycled in a molten flow state. The maximum operating temperature of the liquid molten salt (after absorbing heat) can reach a high temperature of 600°C.

[0032] The flow direction of the liquid heat exchange medium (molten salt) is as follows: 150°C liquid molten salt is input from the liquid inlet 410, flows through the serpentine heat exchange coil 41, flows down through the transition pipe section 40, and the liquid molten salt continues to flow through the rectangular heat exchange coil 42. After the heat exchange is completed, the liquid molten salt finally flows out from the liquid outlet 420. The 400°C liquid molten salt flowing out from the liquid outlet 420 is finally collected in the heat storage container; Figure 2 As shown, the liquid outlet 420 is located close to the upper part of the connecting end plate 2 (ie, farthest from the heat collecting cover 3).

[0033] The heat collecting cover 3 is provided with an exhaust port 30 at the top thereof for exhausting low-temperature exhaust gas.

Claims

1. A method for recovering waste heat from a quick cooling furnace box of a heat treatment furnace for cold-rolled silicon steel sheets of a motor, characterized in that: The quick cooling furnace box waste heat recovery device adopted in the treatment method includes a furnace box body and a heat collecting hood arranged in front and behind. The furnace box body is fixed with a connecting end plate at its front port and its rear port is connected with the heat collecting hood. The furnace box body is connected with the blue furnace box of the front passage through the connecting end plate and the adapter tube. A serpentine heat exchange coil is arranged in the heat collecting hood. A rectangular heat exchange coil is arranged in the furnace box body along its depth direction. The serpentine heat exchange coil is connected with the rectangular heat exchange coil. The serpentine heat exchange coil has a liquid infusion pipe port for liquid heat exchange medium to enter, and the liquid infusion pipe port is located outside the heat collection cover. The rectangular heat exchange coil has a liquid outlet pipe port for liquid heat exchange medium to be discharged, and the liquid outlet pipe port is located outside the furnace box. The liquid outlet pipe port is externally connected to the heat storage container. The liquid heat exchange medium is liquid molten salt. The temperature in the heat collection cover space is lower than the temperature in the furnace box space. The serpentine heat exchange coil is set at a higher position than the rectangular heat exchange coil, and the two are connected through a transition pipe section. The furnace box is fixed on the frame, and the frame is provided with a plurality of rollers for supporting the feeding mesh belt, which are adjacent to each other and parallel to each other and rotate in the same direction. The two ends of each roller pass through the furnace box and the roller is supported on the frame in a transverse manner. The feeding mesh belt is located in the furnace inner tank and is movably supported on the rollers. The quick cooling furnace box waste heat recovery treatment method adopts countercurrent heat exchange, in which liquid molten salt is input from the infusion pipe port, and exchanges heat with the heat in the heat collecting cover while flowing through the serpentine heat exchange coil. When the heated liquid molten salt flows down through the transition pipe section and the liquid molten salt continues to flow through the rectangular heat exchange coil, it exchanges heat with the high-temperature waste heat filled in the furnace box. After the heat exchange is completed, the liquid molten salt flows out from the liquid outlet and is finally collected in the heat storage container.

2. The method for recovering waste heat from a rapid cooling furnace box of a heat treatment furnace for cold-rolled silicon steel sheets for electric motors according to claim 1, characterized in that A heat insulating layer is arranged between the furnace shell and the furnace inner container of the furnace box.

3. The method for recovering waste heat from a rapid cooling furnace box of a heat treatment furnace for cold-rolled silicon steel sheets for electric motors according to claim 2, characterized in that The staggered bending parts of the serpentine heat exchange coil are respectively fixed on the inner walls of the upper part of the heat collecting cover which are opposite to each other; and the rectangular heat exchange coil is fixed on the furnace inner tank.

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