Well type scrap steel preheating device and electric arc furnace

Abstract

The utility model relates to a well type scrap steel preheating device which comprises a preheating vertical shaft with an opening in the bottom end and a feeding structure arranged below the preheating vertical shaft, and the preheating vertical shaft and the feeding structure are connected and define a feeding port suitable for being in butt joint with a feeding port of an electric furnace. The preheating vertical shaft is provided with a scrap steel inlet, a smoke outlet and a vertical shaft smoke pipe used for being connected with an electric furnace flue, the vertical shaft smoke pipe is located above the scrap steel inlet, and a smoke flow adjusting valve is arranged on the vertical shaft smoke pipe. In addition, the utility model further relates to an electric arc furnace provided with the well type scrap steel preheating device. Electric furnace smoke can enter the preheating vertical shaft from the vertical shaft smoke pipe and the feeding opening, the electric furnace smoke in the vertical shaft smoke pipe can conduct primary preheating on waste steel, the electric furnace smoke entering the feeding opening can conduct secondary preheating on the waste steel, and therefore the preheating effect on the waste steel is improved; the smoke flow in the vertical shaft smoke pipe can be adjusted through the smoke flow adjusting valve, then the smoke flow entering the preheating vertical shaft through the vertical shaft smoke pipe and the feeding opening is distributed, and the waste steel preheating effect is improved.

Description

Technical Field

[0001] This utility model belongs to the field of electric arc furnace smelting technology, specifically relating to a pit-type scrap steel preheating device and an electric arc furnace equipped with the pit-type scrap steel preheating device. Background Technology

[0002] Scrap steel is one of the important raw materials for electric arc furnace steelmaking. Scrap steel preheating can effectively reduce energy consumption; theoretically, for every 100°C increase in preheating temperature, 20 kWh of electricity can be saved per ton of steel. Besides saving energy and reducing consumption, scrap steel preheating can also shorten the smelting cycle and increase productivity. Currently, the more advanced scrap steel preheating technologies mainly include finger-type vertical shaft furnace scrap steel preheating and Consteel-type electric arc furnace scrap steel preheating methods.

[0003] Finger-type vertical shaft furnace scrap preheating involves directly installing the vertical furnace above and to the side of the electric arc furnace. The flue gas from the electric arc furnace passes directly through the fingers to preheat the scrap accumulated on it, ensuring full utilization of the heat from the electric arc furnace flue gas and recovering 60% to 70% of the heat. Consteel-type electric arc furnace scrap preheating utilizes the high-temperature flue gas generated by the furnace to continuously bake and preheat the charge during horizontal transport while continuously feeding. This allows the scrap to reach a temperature of 500℃ to 600℃ before entering the furnace. The preheated flue gas then enters the waste heat recovery system through the combustion chamber. This method achieves continuous preheating, continuous feeding, and continuous melting of scrap, improving productivity.

[0004] However, the two scrap steel preheating processes mentioned above also have drawbacks:

[0005] In the finger-type vertical shaft furnace scrap preheating process, the fingers are frequently subjected to high-intensity heat radiation from the high-temperature flue gas and molten steel for extended periods, as well as heavy impact loads from the scrap steel during loading. This often leads to equipment malfunctions such as steel jamming and sticking, requiring production shutdowns for cleaning and significantly impacting production efficiency. Furthermore, both the fingers and the furnace are cooled by water, and leaks pose a risk of explosion. While the Consteel-type scrap preheating process rarely experiences the risk of steel jamming, the high-temperature flue gas passes primarily through the surface of the scrap layer, leaving the scrap at the bottom largely unheated. This results in a lower average scrap temperature and lower flue gas utilization efficiency. Utility Model Content

[0006] This utility model relates to a pit-type scrap steel preheating device and an electric arc furnace equipped with the pit-type scrap steel preheating device, which can at least solve some of the defects of the prior art.

[0007] This utility model relates to a well-type scrap steel preheating device, including a preheating shaft with an open bottom and a feeding structure located below the preheating shaft. The preheating shaft and the feeding structure are connected and enclosed to form a feeding port suitable for docking with the electric furnace feed port. The preheating shaft is provided with a scrap steel inlet, a flue gas outlet, and a shaft flue pipe for connecting with the electric furnace flue. The shaft flue pipe is located above the scrap steel inlet, and a flue gas flow regulating valve is provided on the shaft flue pipe.

[0008] As one implementation method, the outlet of the vertical shaft flue is inclined downwards.

[0009] As one implementation method, in the preheating shaft, at least the shaft wall on the side where the shaft flue is located and above the shaft flue is designed as a water-cooled shaft wall.

[0010] As one implementation method, in the preheating shaft, the shaft wall located below the shaft flue is equipped with a fume hood.

[0011] As one implementation method, the bottom of the preheating shaft is designed to gradually expand from top to bottom.

[0012] As one implementation method, the top of the preheating shaft is also provided with a flue gas outlet, and the shaft top cover of the preheating shaft is at least partially inclined so that the top of the preheating shaft gradually narrows from bottom to top to the flue gas outlet.

[0013] As one embodiment, the top cover of the preheating shaft includes an inclined section and a horizontal section. The inclined section is connected to one end of the horizontal section near the shaft flue and slopes downward to connect with the shaft wall on the side where the shaft flue is located. The horizontal section extends to the flue gas outlet.

[0014] As one implementation method, the preheating shaft is also equipped with a sealing plate for opening and closing the scrap steel inlet.

[0015] This utility model also relates to an electric arc furnace, including a furnace body and a pit-type scrap steel preheating device as described above.

[0016] As one implementation method, the vertical flue pipe and the electric furnace flue are connected by a flange, and an adjustable-width mixing slit is provided between them.

[0017] This utility model has at least the following beneficial effects:

[0018] In the well-type scrap steel preheating device provided by this utility model, electric furnace flue gas can enter the preheating shaft from the vertical shaft flue and the feeding port. The electric furnace flue gas and scrap steel exchange heat countercurrently to achieve preheating of the scrap steel. Since the vertical shaft flue is located above the feeding port, the electric furnace flue gas in the vertical shaft flue can preheat the scrap steel once, and the electric furnace flue gas entering from the feeding port can preheat the scrap steel a second time, thereby improving the preheating effect of the scrap steel. The flue gas flow rate in the vertical shaft flue can be adjusted by the flue gas flow regulating valve, thereby distributing the flue gas flow rate entering the preheating shaft through the vertical shaft flue and the feeding port, which can effectively improve the preheating effect of the scrap steel. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A schematic diagram of the structure of the well-type scrap steel preheating device provided in this embodiment of the utility model;

[0021] Figure 2 This is a schematic diagram of the fit between the vibrating trough and the feeding trough. Detailed Implementation

[0022] The technical solutions in the embodiments of this utility model are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0023] Example 1

[0024] like Figure 1 This utility model provides a well-type scrap steel preheating device, including a preheating shaft 1 with an open bottom and a feeding structure located below the preheating shaft 1. The preheating shaft 1 is connected to the feeding structure and forms a feeding port suitable for docking with the electric furnace feed port. The preheating shaft 1 is provided with a scrap steel inlet, a flue gas outlet and a shaft flue pipe 15 for connecting with the electric furnace flue 30. The shaft flue pipe 15 is located above the scrap steel inlet.

[0025] The aforementioned vertical shaft flue 15 can be a water-cooled flue, which can improve its service life.

[0026] The vertical flue 15 and the electric furnace flue 30 can be connected by a flange, and an adjustable-width mixing slit can be installed between them.

[0027] The outlet of the vertical smoke pipe 15 is preferably inclined downward, that is, the outlet end of the vertical smoke pipe 15 is lower than its inlet end, so as to avoid scrap steel entering the vertical smoke pipe 15 and damaging the equipment.

[0028] In the above-mentioned scrap steel preheating device, electric furnace flue gas can enter the preheating shaft 1 from the vertical flue pipe 15 and the feeding port. The electric furnace flue gas and scrap steel exchange heat in a countercurrent manner to achieve preheating of the scrap steel. Since the vertical flue pipe 15 is located above the feeding port, the electric furnace flue gas in the vertical flue pipe 15 can preheat the scrap steel once, and the electric furnace flue gas entering from the feeding port can preheat the scrap steel a second time, thereby improving the preheating effect of the scrap steel.

[0029] In one embodiment, such as Figure 1 A flue gas flow regulating valve 151 is provided on the vertical smoke pipe 15. This valve regulates the flow rate of the flue gas in the vertical smoke pipe 15, thereby regulating the flow rate of the flue gas entering the preheating shaft 1 through the vertical smoke pipe 15 and the feeding port, achieving the desired preheating effect for the scrap steel. For example, when the amount of scrap steel in the preheating shaft 1 is small, the flow rate of the flue gas in the vertical smoke pipe 15 can be reduced, correspondingly increasing the flow rate of the flue gas in the feeding port to ensure the preheating effect on the scrap steel. Conversely, when the amount of scrap steel in the preheating shaft 1 is large, the flow rate of the flue gas in the vertical smoke pipe 15 can be increased, correspondingly decreasing the flow rate of the flue gas in the feeding port to ensure the preheating effect on the scrap steel.

[0030] Preferably, such as Figure 1 The preheating shaft 1 is also equipped with a scrap steel flow regulation unit, which can regulate the scrap steel flow in the shaft, or the scrap steel flow supplied to the feeding structure.

[0031] In one embodiment, the vertical shaft flue 15 and the scrap steel flow regulating unit are arranged in a staggered manner, and / or the vertical shaft flue 15 and the scrap steel flow regulating unit are respectively located on opposite sides of the preheating shaft 1. While achieving efficient preheating of scrap steel, this avoids the scrap steel flow regulating unit being directly baked by high-temperature flue gas, effectively improving the working reliability and service life of the scrap steel preheating device.

[0032] In one embodiment, such as Figure 1The scrap steel flow regulating unit includes a limiting plate 161 hinged to the preheating shaft 1 and a limiting drive mechanism 162 for driving the limiting plate 161 to rotate. One end of the limiting plate 161 extends outside the preheating shaft 1 and is connected to the limiting drive mechanism 162 arranged outside the preheating shaft 1. Understandably, the limiting plate 161 is partially located inside the preheating shaft 1 and partially located outside, facilitating the arrangement of the limiting drive mechanism 162 outside the shaft. Optionally, the limiting drive mechanism 162 is a linear drive device, the output end of which is hinged to the limiting plate 161, and the housing of which is hinged to the preheating shaft 1; the linear drive device includes, but is not limited to, cylinders, hydraulic cylinders, etc.

[0033] The aforementioned limiting plate 161 includes, but is not limited to, an arc-shaped plate, with the center side of the arc-shaped plate being its upper side. Using an arc-shaped plate is beneficial for supporting and limiting the scrap steel above, ensuring the scrap steel flow regulation effect.

[0034] When the above two arrangement methods are combined, the reliability and service life of the scrap steel flow regulating unit can be further guaranteed.

[0035] In the case where the vertical smoke pipe 15 and the scrap steel flow regulating unit are arranged in a staggered manner, it means that the actuator of the scrap steel flow regulating unit (such as the aforementioned limiting plate 161) is located below the vertical smoke pipe 15. Preferably, the highest working position of the actuator is not higher than the bottom of the outlet of the vertical smoke pipe 15.

[0036] Preferably, in the preheating shaft 1, at least the shaft wall on the side where the shaft flue pipe 15 is located and above the shaft flue pipe 15 is designed as a water-cooled shaft wall. Since the flue gas temperature in contact with these shaft walls is relatively higher, designing these shaft walls as water-cooled shaft walls can ensure the service life of the preheating shaft 1 and prevent the preheating shaft 1 from being baked by high temperature and causing steel sticking. In addition, the flue gas will accumulate at the top of the shaft, so the top cover of the preheating shaft 1 is also preferably a water-cooled top cover. The remaining shaft walls can be non-water-cooled shaft walls, or all can be water-cooled shaft walls, and different water-cooling intensities are adopted according to the flue gas temperature field distribution law in the shaft. The aforementioned preheating shaft 1 can be a regular or near-regular structure such as a square shaft or a round shaft, or it can be an irregular structure. Optionally, taking a regular shaft such as a square or round shaft as an example, a reference plane is defined. This reference plane is a vertical plane that passes through the central axis of the preheating shaft 1 and is parallel to the rotation axis of the aforementioned limiting plate 161. Through this reference plane, the shaft wall of the preheating shaft 1 can be divided into a first shaft wall 111 and a second shaft wall 112. The shaft flue 15 is set on the second shaft wall 112, and the scrap steel flow regulating unit is set on the first shaft wall 111. At least the wall of the second shaft wall 112 located above the shaft flue 15 is designed as a water-cooled shaft wall. The wall of the second shaft wall 112 located below the shaft flue 15 can be designed as a water-cooled shaft wall or a non-water-cooled shaft wall. The first shaft wall 111 is selectively designed according to the actual situation.

[0037] In the above scheme, the non-water-cooled well wall can be made of fume hood 13, for example, the well wall located below the vertical shaft flue can be made of fume hood 13.

[0038] like Figure 1 The bottom of the preheating shaft 1 is preferably designed to gradually expand from top to bottom, which facilitates the flow of scrap steel and the operation of the scrap steel flow regulation unit.

[0039] The aforementioned preheating shaft 1 can cover the feeding structure to ensure that the scrap steel falls accurately onto the feeding structure, while preventing the flue gas from escaping. Correspondingly, a seal can be made between the feeding structure and the bottom of the preheating shaft 1 to prevent the flue gas from escaping from the gaps between the equipment.

[0040] In one embodiment, such as Figure 1 The preheating shaft 1 is also equipped with a flue gas outlet at its top. The shaft top cover 12 is at least partially inclined, so that the top of the preheating shaft 1 gradually narrows from bottom to top to the flue gas outlet, which is conducive to the accumulation and discharge of flue gas at the top of the shaft. Furthermore, as... Figure 1The shaft top cover 12 includes an inclined section 121 and a horizontal section 122. The inclined section 121 is connected to the end of the horizontal section 122 near the shaft flue pipe 15 and is inclined downward to connect with the shaft wall on the side where the shaft flue pipe 15 is located. The flue gas outlet is located on the opposite side shaft wall of the preheating shaft 1, which is conducive to the countercurrent heat exchange between the flue gas and the scrap steel and improves the heat exchange effect.

[0041] The flue gas outlet is connected to a flue gas connection pipe 17, which is used to connect to the subsequent flue gas treatment mechanism, including but not limited to connecting the flue gas connection pipe 17 to the settling combustion chamber 40.

[0042] The flue gas outlet is preferably located above the scrap steel inlet.

[0043] The scrap steel inlet is connected to a feeding unit 50, which is preferably a slant bridge loading device that can transport scrap steel from a lower position to a higher position, including but not limited to slat conveyors, chain conveyors, etc. Scrap steel can be hoisted onto the slant bridge loading device by an overhead crane, a steel grabber, or a magnetic chuck.

[0044] More preferably, such as Figure 1 The preheating shaft 1 is also equipped with a sealing plate 14 for opening and closing the scrap steel inlet. The sealing plate 14 is mainly used to seal the scrap steel inlet during electric arc furnace smelting to prevent flue gas from overflowing from the scrap steel inlet. Optionally, the sealing plate 14 is hinged to the top of the scrap steel inlet and can hang freely when there is no scrap steel support, thereby automatically closing the scrap steel inlet.

[0045] In one embodiment, such as Figure 1 and Figure 2 The feeding structure includes a vibrating trough 22, a feeding trough 23, and a feeding trolley 24. The discharge end of the vibrating trough 22 is movably disposed in the feeding trough 23, and the other end is connected to a vibrator 21. The feeding trough 23 is mounted on the feeding trolley 24. The feeding trolley 24 is movably disposed on the workshop foundation such that the feeding trough 23 has a feeding position for inserting into the electric furnace feed port and a clearance position for leaving the electric furnace feed port.

[0046] The vibrator 21 is preferably adjustable in both amplitude and frequency, which can better realize the feeding of scrap steel.

[0047] The aforementioned vibrating trough 22 is preferably a C-shaped trough, and the feeding trough 23 is also preferably a C-shaped trough. The front end (discharge end) of the vibrating trough 22 is inserted into the feeding trough 23 from the rear end. The vibration of the vibrating trough 22 can both allow the scrap steel in the vibrating trough 22 to enter the feeding trough 23 and push the scrap steel in the feeding trough 23 forward. The receiving surface of the vibrating trough 22 can be designed as an inclined surface to facilitate the forward movement of the scrap steel; the receiving surface of the feeding trough 23 is also preferably designed as an inclined surface.

[0048] This includes, but is not limited to, installing rollers at the bottom of the vibrating trough 22 so that the vibrating trough 22 can roll in the feeding trough 23.

[0049] Furthermore, the feeding trolley 24 is equipped with a vibrator, so that the feeding trough 23 also has a vibratory feeding function; preferably, the vibrator has adjustable amplitude and vibration frequency, which can better realize scrap steel feeding.

[0050] The loading trolley 24 is equipped with a trolley drive unit, which includes, but is not limited to, driving equipment such as hydraulic cylinders and pneumatic cylinders; the loading trolley 24 can pull the loading trough 23 out of the electric furnace feed port during steps such as tapping, so as to prevent interference between the electric furnace feed port and the loading trough 23 when the furnace body tilts.

[0051] Example 2

[0052] This utility model also relates to an electric arc furnace, including a furnace body and a pit-type scrap steel preheating device provided in the above embodiment 1. The specific structure of the pit-type scrap steel preheating device and its connection with the furnace body have been described in the above embodiment 1, and will not be repeated here.

[0053] 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, improvements, etc., 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. A well-type scrap steel preheating device, characterized in that, The device includes a preheating shaft with an opening at the bottom and a feeding structure located below the preheating shaft. The preheating shaft and the feeding structure are connected and enclosed to form a feeding port suitable for docking with the electric furnace feed port. The preheating shaft is provided with a scrap steel inlet, a flue gas outlet, and a shaft flue pipe for connecting to the electric furnace flue. The shaft flue pipe is located above the scrap steel inlet and is provided with a flue gas flow regulating valve.

2. The well-type scrap steel preheating device as described in claim 1, characterized in that: The outlet of the vertical shaft flue pipe slopes downwards.

3. The well-type scrap steel preheating device as described in claim 1, characterized in that: In the preheating shaft, at least the shaft wall on the side where the shaft flue is located and above the shaft flue is designed as a water-cooled shaft wall.

4. The well-type scrap steel preheating device as described in claim 1, characterized in that: In the preheating shaft, the shaft wall located below the smoke pipe is equipped with a smoke hood.

5. The well-type scrap steel preheating device as described in claim 1 or 4, characterized in that: The bottom of the preheating shaft is designed to gradually expand from top to bottom.

6. The well-type scrap steel preheating device as described in claim 1, characterized in that: The top of the preheating shaft is also provided with a flue gas outlet. The top cover of the preheating shaft is at least partially inclined, and the top of the preheating shaft gradually narrows from bottom to top to the flue gas outlet.

7. The well-type scrap steel preheating device as described in claim 6, characterized in that: The top cover of the preheating shaft includes an inclined section and a horizontal section. The inclined section is connected to one end of the horizontal section near the shaft flue and slopes downward to connect with the shaft wall on the side where the shaft flue is located. The horizontal section extends to the flue gas outlet.

8. The well-type scrap steel preheating device as described in claim 1, characterized in that: The preheating shaft is also equipped with a sealing plate for opening and closing the scrap steel inlet.

9. An electric arc furnace, comprising a furnace body, characterized in that, It also includes the well-type scrap preheating device as described in any one of claims 1 to 8.

10. The electric arc furnace as described in claim 9, characterized in that: The vertical flue and the electric furnace flue are connected by a flange, and an adjustable-width mixing slit is provided between them.

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