Steelmaking electric arc furnace

Abstract

The utility model provides a steelmaking electric arc furnace which comprises an electric arc furnace body and a horizontal steel scrap conveying and preheating device, and the electric arc furnace body is arranged at an outlet of the horizontal steel scrap conveying and preheating device and used for receiving steel scrap from the horizontal steel scrap conveying and preheating device and smelting the received steel scrap. Molten steel and slag are obtained; the horizontal waste steel conveying and preheating device is used for preheating the waste steel received from the waste steel feeding device and conveying the preheated waste steel to the electric arc furnace body; the horizontal steel scrap conveying and preheating device comprises a steel scrap conveying device, a horizontal connecting trolley, a horizontal connecting trolley smoke hood, a steel scrap preheating channel smoke hood, a dynamic sealing device, a gas collecting header pipe, a primary flue and a settling chamber. By means of the steel-making electric arc furnace, the double effects of reducing smelting energy consumption and improving the production rate can be achieved.

Description

Technical Field

[0001] The utility model relates to the field of electric arc furnace steelmaking, in particular to an electric arc furnace for steelmaking. Background Art

[0002] In the modern steel industry, ultra-high power electric arc furnaces (EAFs) have become one of the main methods of steelmaking due to their high efficiency and environmental protection characteristics. However, during the steelmaking process, electric arc furnaces generate a large amount of high-temperature flue gas, which will carry away a large amount of heat during the emission process, accounting for about half of the input electric energy. This waste of energy not only causes resource losses but also increases production costs. To reduce energy losses and improve production efficiency, the scrap preheating technology has emerged. This technology recovers the heat in the discharged flue gas and preheats the scrap before entering the furnace to a certain temperature, thereby reducing energy consumption during the smelting process and shortening the melting time. The traditional method is to use a horizontal scrap preheating electric furnace, where the scrap exchanges heat with the high-temperature flue gas in the preheating section. Although this design can preheat the scrap to 250 - 300°C, since the heat exchange mainly occurs between the top-layer scrap and the flue gas, the preheating effect of the lower-layer scrap is not ideal, resulting in the actual preheating temperature being much lower than the claimed value.

[0003] To improve this problem, a shaft-type scrap preheating electric furnace has been developed. In this design, the high-temperature flue gas rises from the bottom of the shaft and exchanges heat more fully with the cold scrap, and it is expected that the scrap can be preheated to 600°C. However, actual operation data shows that the preheating temperature is usually between 500 - 540°C. Although the preheating effect has been improved, this high-temperature preheating also brings new problems, that is, a large amount of toxic gases may be generated during the preheating process, especially when using cheap scrap containing chlorinated hydrocarbons such as paint, grease, and plastics. To meet environmental protection requirements, these toxic flue gases must be treated. The usual method is to use burners to heat the flue gas to above 1000°C to decompose the toxic substances, and then rapidly cool it by spraying water mist to prevent the secondary generation of toxic substances. Finally, activated carbon powder is sprayed into the flue gas to adsorb the remaining toxic substances. This process not only increases the complexity of the system but also reduces the energy-saving effect of scrap preheating due to the need for additional fuel.

[0004] In summary, although the scrap preheating technology has significant advantages in improving production efficiency and reducing energy consumption, there are still problems in its actual application, such as unsatisfactory preheating effect and complex treatment of toxic gases. Therefore, developing an electric arc furnace for steelmaking that can effectively increase the scrap preheating temperature and simplify the toxic gas treatment process is a technical challenge that the current steel industry urgently needs to solve. Summary of the Utility Model

[0005] An embodiment of the utility model provides an electric arc furnace for steelmaking to achieve the dual effects of reducing smelting energy consumption and improving productivity.

[0006] To achieve the above object, on the one hand, a steelmaking electric arc furnace is provided, which includes: an electric arc furnace body and a horizontal scrap conveying and preheating device, wherein:

[0007] The electric arc furnace body is arranged at the outlet of the horizontal scrap conveying and preheating device, and is used to receive scrap from the horizontal scrap conveying and preheating device, and smelt the received scrap to obtain molten steel and slag;

[0008] The horizontal scrap conveying and preheating device is used to preheat the scrap received from the scrap feeding device and convey the preheated scrap to the electric arc furnace body. Among them, the horizontal scrap conveying and preheating device includes: a scrap conveying device, a horizontal connecting trolley, a horizontal connecting trolley hood, a scrap preheating channel hood, a dynamic sealing device, a main gas collecting pipe, a primary flue and a settling chamber;

[0009] The scrap conveying device is used to receive scrap from the scrap feeding device and transport the received scrap to the electric arc furnace body through the horizontal connecting trolley;

[0010] The horizontal connecting trolley hood is arranged above the horizontal connecting trolley, and is used to provide a passage for the outflowing flue gas of the electric arc furnace body and the transportation of the scrap, and provide a closed environment for the process of preheating the scrap with high-temperature flue gas;

[0011] The dynamic sealing device is connected to the scrap preheating channel hood, and is used to provide a passage for the transportation of the scrap, limit the amount of cold air entering the passage, and prevent the flue gas in the passage from escaping;

[0012] The scrap preheating channel hood is respectively connected to the horizontal connecting trolley hood and the dynamic sealing device, and is located between the horizontal connecting trolley hood and the dynamic sealing device. The bottom is connected to the main gas collecting pipe through a plurality of air extraction boxes corresponding to a plurality of gas collecting branches one by one;

[0013] The main gas collecting pipe is respectively connected to the plurality of gas collecting branches and the primary flue, and is used to collect and mix the flue gas of the plurality of gas collecting branches;

[0014] The primary flue is arranged between the main gas collecting pipe and the settling chamber, and is used to divert the flue gas collected and mixed in the main gas collecting pipe to the settling chamber; and

[0015] The settling chamber is connected to the primary flue, and is used to separate and settle the dust particles in the collected and mixed flue gas that meet the predetermined size conditions.

[0016] Preferably, for the steelmaking electric arc furnace, the horizontal scrap conveying and preheating device further includes:

[0017] A scrap feeding device for conveying the scrap onto the scrap conveying device to obtain a scrap layer;

[0018] Multiple scrap conveying device driving wheels for driving the scrap conveying device to convey the scrap to the horizontal connecting trolley hood;

[0019] The multiple air extraction bellows, located at the bottom of the scrap preheating channel hood, for sucking the flue gas in the scrap preheating channel hood through the scrap layer;

[0020] The multiple gas collecting branch pipes, each connected to one of the air extraction bellows and connected to the gas collecting main pipe, and for conveying the flue gas to the gas collecting main pipe.

[0021] Preferably, for the steelmaking electric arc furnace, the horizontal connecting trolley adopts a sliding and sticking operation mode to horizontally feed the scrap into the electric arc furnace body, and when the furnace body of the electric arc furnace body needs to tilt for slag tapping or steel tapping, it completely withdraws to the outside of the upper furnace shell of the electric arc furnace body.

[0022] Preferably, for the steelmaking electric arc furnace, the horizontal connecting trolley hood adopts a water-cooled structure.

[0023] Preferably, for the steelmaking electric arc furnace, a hydraulic movable hood is provided at the near-furnace side end of the horizontal connecting trolley hood; and / or,

[0024] The horizontal connecting trolley hood is provided with a tilting hydraulic structure.

[0025] Preferably, for the steelmaking electric arc furnace, the scrap preheating channel hood adopts a refractory lining structure, and several groups of burners are arranged on the scrap preheating channel hood.

[0026] Preferably, for the steelmaking electric arc furnace, the dynamic sealing device is connected to an exhaust pipe, an exhaust fan is provided on the exhaust pipe, the exhaust fan is linked with the main fan of the primary flue gas of the electric arc furnace body, and the end of the exhaust pipe is incorporated into the secondary flue gas pipeline.

[0027] Preferably, for the steelmaking electric arc furnace, the scrap conveying device is composed of a trough body and a grate bar, wherein both the trough body and the grate bar are made of a predetermined high-temperature resistant metal material, and several trough bodies are connected in series front and back to form the scrap conveying device.

[0028] Preferably, for the steelmaking electric arc furnace, the scrap feeding device adopts the structural form of a magnetic disk crane or a steel grabber.

[0029] The above technical solution has the following technical effects:

[0030] In the technical solution of this embodiment, the scrap is preheated by using an improved horizontal scrap conveying and preheating device and transported to the electric arc furnace for smelting, achieving efficient preheating of the scrap before entering the electric arc furnace, reducing the energy demand of the electric arc furnace itself. At the same time, through the closed preheating environment and flue gas management system of the horizontal scrap conveying and preheating device, the heat loss and flue gas leakage during the preheating process are effectively controlled, improving the energy utilization rate, and making the process layout more optimized. Further, the flue gas generated during the preheating process is treated by the sedimentation chamber, achieving the technical effects of energy conservation, consumption reduction, environmental protection and emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic structural diagram of an electric arc furnace for steelmaking according to an embodiment of the present invention;

[0032] Figure 2 It is a schematic structural diagram of a scrap conveying device in an electric arc furnace for steelmaking according to an embodiment of the present invention;

[0033] Among them, 1 is the main body of the electric arc furnace, 2 is the horizontal connecting trolley, 3 is the hood of the horizontal connecting trolley, 4 is the hood of the scrap preheating channel, 5 is the dynamic sealing device, 6 is the scrap feeding device, 7 is the scrap layer, 8 is the scrap conveying device, 9 is the driving wheel of the scrap conveying device, 10 is the air extraction air box, 11 is the collecting branch pipe, 12 is the collecting main pipe, 13 is the primary flue, 14 is the sedimentation chamber; a is the tank body, b is the grate bar, c is the gap. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] To further illustrate the embodiments, the present invention provides drawings. These drawings are a part of the disclosure of the present invention, mainly used to illustrate the embodiments, and can be used to explain the operating principle of the embodiments in conjunction with the relevant descriptions in the specification. With reference to these contents, those of ordinary skill in the art should be able to understand other possible implementation manners and the advantages of the present invention. The components in the drawings are not drawn to scale, and similar component symbols are usually used to represent similar components.

[0035] The present invention will be further described below in conjunction with the drawings and specific embodiments.

[0036] Embodiment 1:

[0037] In order to achieve the dual effects of reducing smelting energy consumption and improving productivity, this embodiment provides an electric arc furnace for steelmaking. Figure 1 It is a schematic structural diagram of an electric arc furnace for steelmaking according to an embodiment of the present invention. As Figure 1 shown, the electric arc furnace for steelmaking includes: the main body 1 of the electric arc furnace and a horizontal scrap conveying and preheating device, wherein:

[0038] The electric arc furnace body 1 is arranged at the outlet of the horizontal scrap steel conveying and preheating device, and is used to receive scrap steel from the horizontal scrap steel conveying and preheating device, and smelt the received scrap steel to obtain molten steel and slag;

[0039] The horizontal scrap steel conveying and preheating device is used to preheat the scrap steel received from the scrap steel feeding device and convey the preheated scrap steel to the electric arc furnace body 1. Among them, the horizontal scrap steel conveying and preheating device includes: a scrap steel conveying device 8, a horizontal connecting trolley 2, a horizontal connecting trolley hood 3, a scrap steel preheating channel hood 4, a dynamic sealing device 5, a gas collecting main pipe 12, a primary flue 13 and a settling chamber 14;

[0040] The scrap steel conveying device 8 is used to receive scrap steel from the scrap steel feeding device 6 and transport the received scrap steel to the electric arc furnace body 1 through the horizontal connecting trolley 2;

[0041] The horizontal connecting trolley hood 3 is arranged above the horizontal connecting trolley 2 and is used to provide a passage for the outflowing flue gas of the electric arc furnace body 1 and the transportation of scrap steel, and provide a closed environment for the process of preheating scrap steel with high-temperature flue gas;

[0042] The dynamic sealing device 5 is connected to the scrap steel preheating channel hood 4 and is used to provide a passage for the transportation of scrap steel, limit the amount of cold air entering the channel, and prevent the flue gas in the channel from escaping;

[0043] The scrap steel preheating channel hood 4 is respectively connected to the horizontal connecting trolley hood 3 and the dynamic sealing device 5, and is located between the horizontal connecting trolley hood 3 and the dynamic sealing device 5. The bottom is connected to the gas collecting main pipe 12 through a plurality of exhaust air boxes 10 corresponding to a plurality of gas collecting branch pipes 11 one by one;

[0044] The gas collecting main pipe 12 is respectively connected to a plurality of gas collecting branch pipes 11 and the primary flue 13, and is used to collect and mix the flue gas of a plurality of gas collecting branch pipes 11;

[0045] The primary flue 13 is arranged between the gas collecting main pipe 12 and the settling chamber 14 and is used to divert the flue gas collected and mixed in the gas collecting main pipe 13 to the settling chamber 14; and

[0046] The settling chamber 14 is connected to the primary flue 13 and is used to separate and settle the dust particles in the collected and mixed flue gas that meet the predetermined size conditions.

[0047] Preferably, the electric arc furnace body 1 includes: an electric arc furnace molten bath, which is composed of molten steel and molten slag and is the place where scrap melting and steelmaking reactions take place; an electric arc furnace hearth, which is built with refractory materials and defines the shape and size of the molten bath, such as the diameter and depth of the molten bath in the main melting area; an upper furnace shell of the electric arc furnace, which adopts a water-cooled structure and provides an opening channel for the high-temperature flue gas generated during the molten bath steelmaking reaction process to preheat scrap, and also provides an opening channel for the installation of wall oxygen lances and carbon lances; an electric arc furnace cover, which adopts a water-cooled structure and maintains the atmosphere and temperature in the furnace within a suitable range during the smelting process. At the same time, it also provides channels for the up and down movement of the electrodes, the discharge of flue gas in the furnace, and the loading of bulk materials, so as to meet the requirements of the smelting process and provide a good workshop production environment; graphite electrodes, which are used to introduce electric energy into the electric arc furnace and convert it into the arc heat of the electric arc to heat the molten bath and melt the scrap.

[0048] Preferably, the horizontal connecting trolley 2 adopts a sliding and sticking operation mode, conveys the scrap to the electric arc furnace through horizontal displacement, and can completely withdraw to the outside of the upper furnace shell when the electric arc furnace body needs to tilt for slag tapping / steel tapping, so as to avoid collision with the tilted upper furnace shell.

[0049] Preferably, the hood of the horizontal connecting trolley 3 adopts a water-cooled structure, provides a channel for the outflow flue gas of the electric arc furnace body and the conveyance of scrap, and also provides a closed environment for the process of preheating scrap with high-temperature flue gas. In a specific embodiment, a hydraulic movable hood is provided at the end of the near-furnace side of the hood of the horizontal connecting trolley 3 to facilitate making room for the rotation of the electric arc furnace cover. At the same time, the hood of the horizontal connecting trolley 3 is also provided with a tilting hydraulic mechanism, which can tilt the hood of the horizontal connecting trolley 3 as a whole to facilitate the maintenance of the inside of the hood of the horizontal connecting trolley 3 and the horizontal connecting trolley 2.

[0050] Preferably, the hood of the scrap preheating channel 4 adopts a structure with refractory lining, provides a channel for the outflow flue gas of the electric arc furnace body and the conveyance of scrap, and also provides a closed environment for the process of preheating scrap with high-temperature flue gas. In a specific implementation, a number of groups of burners are arranged on the hood of the scrap preheating channel 4 to enhance the scrap preheating effect.

[0051] Preferably, the dynamic sealing device 5 is in the combined area of scrap feeding and preheating, provides a channel for scrap to enter the preheating area. When the pressure in the scrap preheating channel 4 fluctuates, on the one hand, it prevents too much cold air from entering the preheating area, thereby weakening the preheating effect; on the other hand, it prevents the high-temperature and high-dust flue gas in the preheating channel from escaping into the plant space, thereby deteriorating the working and external environment. In a specific implementation, the dynamic sealing device 5 is connected with an exhaust pipe, and an exhaust fan is arranged on the exhaust pipe. The exhaust fan is linked with the main fan of the primary flue gas of the electric arc furnace, and the end of the exhaust pipe is incorporated into the secondary flue gas pipeline of the plant.

[0052] Preferably, the scrap feeding device 6 adopts structural forms such as an electromagnetic crane or a steel grabber to continuously supply scrap to the scrap conveying device 8 for scrap transportation.

[0053] Preferably, the scrap layer 6 composed of the scrap fed onto the scrap conveying device 8 through the scrap feeding device 6 can optimize the layout of the transported scrap in layers according to the characteristics of the incoming scrap (such as shape, size, weight, etc.) to achieve optimized preheating effect and smelting process.

[0054] Preferably, the scrap conveying device 8 receives the scrap provided by the scrap feeding device 6, carries the scrap for horizontal movement, and continuously transports the scrap to the horizontal connecting trolley 2. Its structure is as Figure 2 shown, consisting of a trough body a, a grate bar b, and a gap c. Both the trough body a and the grate bar b are made of high-temperature resistant metal materials. A number of trough bodies a are connected in series front and back to form a scrap conveying device 8. The gap c between the grate bars b facilitates the passage of the flue gas penetrating the scrap layer 6 without causing the scrap to fall.

[0055] Preferably, the scrap conveying device 8 is provided with a number of driving wheels 9 for the scrap conveying device to continuously supply scrap to the horizontal connecting trolley 2 and at the same time recycle the emptied conveying trough body a back to the feeding area.

[0056] Preferably, the scrap conveying device 8 can adopt a trolley type or a chain plate type structure. The horizontal traveling speed of the scrap is faster than that of the traditional horizontal feeding conveyor, so a thinner layer thickness can be used, thus significantly improving the preheating effect; and adopting a horizontal conveying form can maximize the compatibility with the optimized process layout of the horizontal feeding workshop.

[0057] Preferably, a plurality of air extraction boxes 10 are arranged below the scrap preheating channel hood 4. A number of air extraction boxes 10 are used to suck the flue gas in the scrap preheating channel hood 4 through the scrap layer 6 to improve the heat exchange effect between the two.

[0058] Preferably, a plurality of gas collecting branch pipes 11 are used to connect the air extraction boxes 10 to the gas collecting main pipe 12, and transport the flue gas of each branch of the air extraction boxes 10 that has penetrated the scrap layer 6 and cooled down to the gas collecting main pipe 12.

[0059] Preferably, the gas collecting main pipe 12 is used to connect the gas collecting branch pipes 11 to the primary flue 13 to collect and mix the branch flue gas of the gas collecting branch pipes 11.

[0060] Preferably, the primary flue 13 is used to connect the gas collecting main pipe 12 to the sedimentation chamber 14 to divert the primary flue gas in the gas collecting main pipe 12 to the sedimentation chamber 14.

[0061] Preferably, the front end of the sedimentation chamber 14 is connected to the primary flue 13, and the rear end is connected to the pipeline of the dust collector, which is used to separate and settle the coarse dust particles in the flue gas, reduce the burden on the rear pipeline and the dust collector, and at the same time burn out the unburned components contained in the flue gas here.

[0062] Preferably, the steelmaking electric arc furnace is also provided with a transformer room, a high-voltage room and a hydraulic room.

[0063] Although the present invention is specifically shown and described in combination with the preferred embodiments, those skilled in the art should understand that various changes can be made to the present invention in terms of form and details without departing from the spirit and scope of the present invention defined by the appended claims, and all of them fall within the protection scope of the present invention.

Claims

1. A steelmaking electric arc furnace, characterized in that, Comprising: An electric arc furnace body and a horizontal scrap steel conveying and preheating device, wherein: The electric arc furnace body is arranged at the outlet of the horizontal scrap steel conveying and preheating device, and is used to receive scrap steel from the horizontal scrap steel conveying and preheating device, and smelt the received scrap steel to obtain molten steel and slag; The horizontal scrap steel conveying and preheating device is used to preheat the scrap steel received from the scrap steel feeding device and convey the preheated scrap steel to the electric arc furnace body. Among them, the horizontal scrap steel conveying and preheating device includes: a scrap steel conveying device, a horizontal connecting trolley, a horizontal connecting trolley hood, a scrap steel preheating channel hood, a dynamic sealing device, a gas collecting main pipe, a primary flue and a sedimentation chamber; The scrap steel conveying device is used to receive scrap steel from the scrap steel feeding device and transport the received scrap steel to the electric arc furnace body through the horizontal connecting trolley; The horizontal connecting trolley hood is arranged above the horizontal connecting trolley, and is used to provide a passage for the outflowing flue gas of the electric arc furnace body and the transportation of the scrap steel, and provide a closed environment for the process of preheating the scrap steel with high-temperature flue gas; The dynamic sealing device is connected to the scrap steel preheating channel hood, and is used to provide a passage for the transportation of the scrap steel, limit the amount of cold air entering the channel, and prevent the flue gas in the channel from escaping; The scrap steel preheating channel hood is respectively connected to the horizontal connecting trolley hood and the dynamic sealing device, and is located between the horizontal connecting trolley hood and the dynamic sealing device. The bottom is connected to the gas collecting main pipe through a plurality of air extraction bellows corresponding to a plurality of gas collecting branch pipes one by one; The gas collecting main pipe is respectively connected to the plurality of gas collecting branch pipes and the primary flue, and is used to collect and mix the flue gas of the plurality of gas collecting branch pipes; The primary flue is arranged between the gas collecting main pipe and the sedimentation chamber, and is used to divert the flue gas collected and mixed in the gas collecting main pipe to the sedimentation chamber; and The sedimentation chamber is connected to the primary flue, and is used to separate and settle the dust particles meeting the predetermined size conditions in the flue gas after collection and mixing.

2. The steelmaking electric arc furnace according to claim 1, characterized in that The horizontal scrap steel conveying and preheating device further includes: The scrap steel feeding device is used to convey the scrap steel onto the scrap steel conveying device to obtain a scrap steel layer; A plurality of driving wheels of the scrap steel conveying device are used to drive the scrap steel conveying device to convey the scrap steel to the horizontal connecting trolley hood; The plurality of air extraction bellows are located at the bottom of the scrap steel preheating channel hood, and are used to suck the flue gas in the scrap steel preheating channel hood through the scrap steel layer; The plurality of gas collecting branch pipes are connected to the air extraction bellows one by one, and are connected to the gas collecting main pipe, and are used to convey the flue gas to the gas collecting main pipe.

3. The steelmaking electric arc furnace according to claim 1, characterized in that, The horizontal connecting trolley adopts a sliding and sticking operation mode to horizontally feed the scrap steel into the electric arc furnace body, and when the furnace body of the electric arc furnace needs to tilt for slag tapping or steel tapping, it completely withdraws to the outside of the upper furnace shell of the electric arc furnace body.

4. The steelmaking electric arc furnace according to claim 1, characterized in that, The horizontal connecting trolley hood adopts a water-cooled structure.

5. The steelmaking electric arc furnace according to claim 1, characterized in that, The near-furnace side end of the horizontal connecting trolley hood is provided with a hydraulic movable hood; and / or, The horizontal connecting trolley hood is provided with a tilting hydraulic structure.

6. The steelmaking electric arc furnace according to claim 1, wherein The scrap preheating channel hood adopts a refractory lining structure, and several groups of burners are arranged on the scrap preheating channel hood.

7. The steelmaking electric arc furnace according to claim 1, characterized in that, The dynamic sealing device is connected to the exhaust pipe, and an exhaust fan is arranged on the exhaust pipe. The exhaust fan is linked with the main fan of the primary flue gas of the electric arc furnace body, and the end of the exhaust pipe is incorporated into the secondary flue gas pipeline.

8. The steelmaking electric arc furnace according to claim 1, characterized in that, The scrap conveying device is composed of a trough body and a grate bar. Both the trough body and the grate bar are made of a predetermined high-temperature resistant metal material, and several trough bodies are connected in series front and back to form the scrap conveying device.

9. The steelmaking electric arc furnace according to claim 2, characterized in that The scrap feeding device adopts the structural form of a magnetic disk crane or a steel grabber.

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