A steelmaking device with scrap preheating function

Abstract

The utility model provides a kind of steelmaking device with scrap steel preheating function, including scrap steel conveying component, scrap steel preheating shaft and arc furnace, the output end of scrap steel conveying component is communicated with the scrap steel inlet of scrap steel preheating shaft, and the scrap steel outlet of scrap steel preheating shaft is communicated with the scrap steel inlet of arc furnace, water-cooling finger is equipped in scrap steel preheating shaft, and dynamic sealing assembly that prevents that smoke escapes in scrap steel preheating shaft and external cold wind enters in scrap steel preheating shaft is equipped at the junction of scrap steel conveying component and scrap steel preheating shaft.The utility model carries out preheating to scrap steel using shaft type scrap steel preheating mode, preheating temperature is high, realizes the efficient preheating of scrap steel, to reduce electric energy and chemical energy consumption;And by setting dynamic sealing assembly above scrap steel preheating shaft, to ensure that internal high-temperature flue gas does not escape, while the amount of external cold wind is small, improve the heat transfer efficiency between flue gas and scrap steel, guarantee preheating effect, to realize the energy-saving effect of whole.

Description

Technical Field

[0001] This utility model belongs to the field of metallurgical engineering technology, specifically relating to a steelmaking device with scrap steel preheating function. Background Technology

[0002] The importance of energy conservation and consumption reduction in electric arc furnace (EAF) steelmaking lies in its ability to effectively address rising energy prices and energy shortages, while simultaneously improving production efficiency and economic benefits. The application of scrap preheating technology in EAF steelmaking is of great significance. Scrap preheating can significantly shorten smelting time, increase production efficiency, reduce electricity consumption, and avoid the explosion risk caused by wet scrap entering the furnace, thereby ensuring plant safety and preventing accidental equipment damage. Furthermore, scrap preheating technology can increase the melting rate and plasticity of scrap, turning "cold material" into "hot material," accelerating the production pace, and reducing energy consumption. Scrap preheating technology not only helps reduce steelmaking costs and improve enterprise competitiveness but also reduces environmental pollution and promotes the green development of the steel industry.

[0003] However, existing scrap preheating technologies also face some challenges: (1) Low preheating temperature: In horizontal continuous feeding electric arc furnaces, due to the resistance of scrap steel, the gas flows upward, reducing the heat transfer efficiency between flue gas and scrap steel. This problem leads to poor preheating effect and affects the overall energy-saving effect; (2) Complexity of equipment and process: The design and implementation of scrap preheating systems need to consider various factors, such as equipment layout, heat transfer behavior and thermodynamic calculations. In addition, different types of scrap preheating technologies (vertical shaft type and consteel type) have their own advantages and disadvantages, and need to be selected and optimized according to specific circumstances; (3) Technical stability: Although some new technologies, such as quantum electric arc furnaces, have certain advantages in reducing power consumption and shortening smelting cycles, water-cooled fingers are prone to water leakage accidents under the impact of large quantities of scrap steel, so the stability of the system still needs further verification. Although electric arc furnace scrap preheating technology has significant advantages in energy saving, emission reduction and improving production efficiency, it still faces many challenges in practical applications, and these problems need to be solved through technological innovation and process improvement. Utility Model Content

[0004] The purpose of this invention is to provide a steelmaking device with scrap steel preheating function, which can at least solve some of the defects existing in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A steelmaking apparatus with scrap steel preheating function includes a scrap steel conveying assembly, a scrap steel preheating shaft, and an electric arc furnace. The output end of the scrap steel conveying assembly is connected to the scrap steel inlet of the scrap steel preheating shaft, and the scrap steel outlet of the scrap steel preheating shaft is connected to the scrap steel inlet of the electric arc furnace. The scrap steel preheating shaft is equipped with water-cooled fingers. A dynamic sealing assembly is provided at the connection between the scrap steel conveying assembly and the scrap steel preheating shaft to prevent flue gas from escaping from the scrap steel preheating shaft and external cold air from entering the scrap steel preheating shaft.

[0007] Furthermore, the dynamic sealing assembly includes a sealing cover, a first variable frequency fan, and movable baffles. The sealing cover covers the top of the scrap steel preheating shaft, and the end of the scrap steel conveying assembly extends into the sealing cover. The first variable frequency fan is mounted on the sealing cover. There are two sets of movable baffles, spaced apart along the scrap steel running direction. The upper end of the movable baffle is rotatably connected to the sealing cover, and the lower end of the movable baffle contacts the surface of the scrap steel conveying assembly. The sealing cover, movable baffles, and the end of the scrap steel conveying assembly enclose a closed space, and the first variable frequency fan is connected to this closed space.

[0008] Furthermore, a second variable frequency fan is installed at the flue gas outlet at the top of the scrap steel preheating shaft, and the second variable frequency fan is interlocked with the first variable frequency fan.

[0009] Furthermore, each set of movable baffles is composed of several blocks seamlessly assembled side by side along a direction perpendicular to the scrap steel running direction, and the upper ends of each block are rotatably connected to the same rotating shaft.

[0010] Furthermore, the stop is a wedge-shaped structure, with the thinner end of the wedge connected to the rotating shaft.

[0011] Furthermore, a temperature sensor is installed at the flue gas outlet at the top of the scrap steel preheating shaft.

[0012] Furthermore, the scrap steel conveying assembly includes a chain conveyor with sequentially connected inclined and horizontal sections. The horizontal section is connected to the scrap steel inlet at the top of the scrap steel preheating shaft, and the dynamic sealing assembly is arranged on the horizontal section.

[0013] Furthermore, the angle α between the inclined segment and the horizontal plane is 35-40°.

[0014] Furthermore, a buffer slide is provided between the scrap steel conveying assembly and the scrap steel inlet of the scrap steel preheating shaft.

[0015] Furthermore, the water-cooled finger is equipped with a pressure sensor, and the pressure sensor is interlocked with the scrap steel conveying assembly.

[0016] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0017] (1) The steelmaking device with scrap steel preheating function provided by this utility model adopts a vertical shaft scrap steel preheating method to preheat scrap steel. The preheating temperature is high, which realizes efficient preheating of scrap steel, thereby reducing the consumption of electrical energy and chemical energy. Furthermore, by setting a dynamic sealing component above the scrap steel preheating shaft, the high-temperature flue gas inside is prevented from escaping, while the amount of external cold air entering is small, which improves the heat transfer efficiency between flue gas and scrap steel, ensures the preheating effect, and thus achieves the overall energy-saving effect.

[0018] (2) The steelmaking device with scrap steel preheating function provided by this utility model adopts a continuous feeding method. The scrap steel is continuously transported to the scrap steel preheating shaft through the scrap steel conveying component, which avoids the huge impact on the water-cooled fingers caused by the traditional one-time addition of scrap steel bags. Furthermore, the impact is further reduced under the action of the buffer slide plate, which can effectively improve the life of the water-cooled fingers and save equipment maintenance costs.

[0019] The present invention will be further described in detail below with reference to the accompanying drawings. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the steelmaking apparatus in an embodiment of this utility model;

[0021] Figure 2 This is a front view of the dynamic sealing assembly in an embodiment of this utility model;

[0022] Figure 3 This is a side view of the dynamic sealing component in an embodiment of this utility model.

[0023] Explanation of reference numerals in the attached drawings: 1. Electric arc furnace; 2. Water-cooled finger; 3. Scrap steel preheating shaft; 4. Second variable frequency fan; 5. Buffer slide plate; 6. Sealing cover; 7. Dynamic sealing assembly; 8. Scrap steel conveying assembly; 9. First variable frequency fan; 10. Movable baffle; 11. Stop block. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0025] In the description of this utility model, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0026] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "connection" and "joining" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, abutting connections, or integral connections. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0027] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of this utility model, unless otherwise stated, "a plurality of" or "several" means two or more.

[0028] like Figure 1As shown, this embodiment provides a steelmaking apparatus with scrap steel preheating function, including a scrap steel conveying assembly 8, a scrap steel preheating shaft 3, and an electric arc furnace 1. The scrap steel inlet and flue gas outlet of the scrap steel preheating shaft 3 are located at its upper part, and the scrap steel outlet of the scrap steel preheating shaft 3 is located at its lower part. The output end of the scrap steel conveying assembly 8 is connected to the scrap steel inlet of the scrap steel preheating shaft 3, and the scrap steel outlet of the scrap steel preheating shaft 3 is connected to the scrap steel inlet of the electric arc furnace 1. The scrap steel preheating shaft 3 is provided with a water-cooled finger 2. The connection between the scrap steel conveying assembly 8 and the scrap steel preheating shaft 3 is provided with a dynamic sealing assembly 7 to prevent the flue gas in the scrap steel preheating shaft 3 from escaping and the external cold air from entering the scrap steel preheating shaft 3. During operation, scrap steel is continuously fed into the water-cooled finger 2 inside the scrap steel preheating shaft 3 through the dynamic sealing component 7 via the scrap steel conveying component 8. When the amount of scrap steel falling into the shaft reaches the target weight for batch processing, the scrap steel conveying component 8 stops conveying scrap steel. At the same time, the scrap steel in the scrap steel preheating shaft 3 begins to enter the centralized preheating stage. When the designed preheating time is reached, the preheated scrap steel is added into the electric arc furnace 1 through the scrap steel outlet of the scrap steel preheating shaft 3, and this batch of scrap steel enters the smelting stage. In this embodiment, a vertical shaft-type scrap steel preheating method is used to preheat the scrap steel. The preheating temperature is high, and the scrap steel can be preheated to 600-800℃ in a short time (3-5 minutes), achieving efficient preheating of the scrap steel and reducing the consumption of electrical and chemical energy. At the same time, due to the design of the dynamic sealing component 7, the escape of high-temperature flue gas and the entry of external cold air into the scrap steel preheating shaft 3 can be minimized during the process of feeding the scrap steel into the scrap steel preheating shaft 3. This can effectively ensure and improve the heat transfer efficiency between the flue gas and the scrap steel, and ensure the preheating effect.

[0029] As one specific implementation method, such as Figure 1 As shown, the scrap steel conveying assembly 8 includes a chain conveyor with a sequentially connected inclined section and a horizontal section. The inclined section is designed to accommodate the scrap steel inlet of the scrap steel preheating shaft 3 located at the top, while the horizontal section is designed to facilitate the formation of a seal with the dynamic sealing assembly 7. The horizontal section is connected to the scrap steel inlet at the top of the scrap steel preheating shaft 3, and the dynamic sealing assembly 7 is arranged on the horizontal section.

[0030] The optimized design places the angle α between the inclined section and the horizontal plane at 35-40°. An angle that is too large will cause the downward component of the scrap steel's gravity along the chain conveyor to exceed the frictional force, causing the scrap steel to slide down naturally and failing to meet the feeding requirements. Conversely, with a fixed shaft height, an angle that is too small will result in an excessively long chain, occupying too much space and wasting resources. The chain conveyor uses gapless chain plates, effectively preventing material leakage and jamming. The operating speed of the chain conveyor can be adjusted as needed, with a maximum scrap steel feeding capacity of 600 t / h.

[0031] In an optimized configuration, a buffer slide plate 5 is provided between the scrap steel conveying assembly 8 and the scrap steel inlet of the scrap steel preheating shaft 3. After passing through the dynamic sealing assembly 7, the scrap steel continuously falls into the water-cooled finger 2 in the scrap steel preheating shaft 3 via the buffer slide plate 5. This avoids the leakage accident caused by the traditional method of large-scale scrap steel falling into the water-cooled finger 2 at once, and can effectively extend the service life of the water-cooled finger 2.

[0032] Furthermore, a pressure sensor (not shown in the figure) is installed on the water-cooled finger 2 to realize real-time weighing of the scrap steel falling in. At the same time, the pressure sensor is designed to be interlocked with the scrap steel conveying assembly 8. When the scrap steel falling in reaches the batch target weight, the interlock controls the scrap steel conveying assembly 8 to stop working. When all the scrap steel on the water-cooled finger 2 is added into the electric arc furnace 1 (i.e., the weight of scrap steel on the water-cooled finger 1 is zero), after the water-cooled finger 1 closes, the interlock controls the scrap steel conveying assembly 8 to start working.

[0033] For a specific implementation of the dynamic sealing component 7 in this embodiment, such as Figure 2 and Figure 3 As shown, the dynamic sealing assembly 7 includes a sealing cover 6, a first variable frequency fan 9 and a movable baffle 10 disposed on the sealing cover 6. The sealing cover 6 covers the scrap steel preheating shaft 3, and the end of the scrap steel conveying assembly 8 extends into the sealing cover 6. The first variable frequency fan 9 is disposed on the sealing cover 6. There are two sets of movable baffles 10, which are arranged at intervals along the scrap steel running direction. The upper end of the movable baffle 10 is rotatably connected to the sealing cover 6, and the lower end of the movable baffle 10 is in contact with the surface of the scrap steel conveying assembly 8. The sealing cover 6, the movable baffle 10 and the end of the scrap steel conveying assembly 8 enclose a closed space, and the first variable frequency fan 9 is connected to this closed space. When the scrap steel conveying assembly 8 conveys scrap steel to the movable baffle 10, the scrap steel continues to move forward under the conveying of the scrap steel conveying assembly 8, pushing the movable baffle 10 to rotate. The movable baffle 10 is always in contact with the scrap steel during its rotation, which can block the entry of external cold air and the escape of internal high-temperature flue gas. After the scrap steel continues to move forward and the movable baffle 10 is separated from it, the movable baffle 10 returns to its initial vertical state under its own gravity, forming a seal with the sealing cover 6 and the scrap steel conveying assembly 8 to block the entry of external cold air and the escape of internal high-temperature flue gas. Through this structural design, it can be ensured that the high-temperature flue gas inside the scrap steel preheating shaft 3 does not escape and the amount of external cold air entering is small, achieving the best environmental protection effect while improving thermal efficiency.

[0034] Since the conveyed scrap steel is irregularly shaped, in this embodiment, each set of movable baffles 10 is optimized by using several baffle blocks 11 seamlessly assembled side by side along the direction perpendicular to the scrap steel running. The upper ends of each baffle block 11 are rotatably connected to the same rotating shaft. When the scrap steel pushes the movable baffles 10, each baffle block 11 can be adapted to the shape of the scrap steel and can better fit and contact each position of the irregular scrap steel to ensure that the escape of high-temperature flue gas and the entry of external cold air are minimized.

[0035] Furthermore, the stop block 11 has a wedge-shaped structure, with the thinner end of the wedge connected to the rotating shaft. This structural design allows the stop block 11 to quickly return to its original position after it separates from the scrap steel.

[0036] In the optimized implementation, a second variable frequency fan 4 is installed at the flue gas outlet at the upper part of the scrap steel preheating shaft 3. The second variable frequency fan 4 is interlocked with the first variable frequency fan 1. Specifically, the suction volumes of the dynamic sealing component 7 and the flue gas outlet at the upper part of the scrap steel preheating shaft 3 are designed to be Q1 and Q2, respectively, with Q2 > Q1. The first variable frequency fan 9 and the second variable frequency fan 4 at the two locations control the suction volume through interlocking cooperation. Under the premise of ensuring that the flue gas does not overflow into the atmosphere through the dynamic sealing port, a slightly negative pressure state is maintained inside the electric arc furnace 1. At this time, (P1-P0) is designed to be controlled between -20Pa and -10Pa, where P0 is the atmospheric ambient pressure and P1 is the pressure inside the electric arc furnace. This control can prevent high-temperature flue gas inside the electric arc furnace 1 from overflowing through the furnace body gaps.

[0037] Furthermore, a temperature sensor (not shown in the figure) is installed at the flue gas outlet of the upper part of the scrap steel preheating shaft 3 to detect the temperature at the flue gas outlet of the upper part of the scrap steel preheating shaft 3 in real time; based on the above-mentioned control of the suction volume of the dynamic sealing component 7 and the flue gas outlet of the upper part of the scrap steel preheating shaft 3, the temperature at the flue gas outlet of the upper part of the scrap steel preheating shaft 3 is simultaneously controlled at 1100-1200℃. The influence of the control of the above-mentioned suction volumes Q1 and Q2 on P0, P1 and the flue gas temperature state is shown in Table 1.

[0038] Table 1:

[0039] state result <![CDATA[Q1 is excessively large, Q2 is excessively small]]> <![CDATA[P1-P0>-10Pa, excessive cold air intake at the scrap steel loading point affects the recovery of heat from high-temperature flue gas. <![CDATA[Q1 is too small, Q2 is too large]]> <![CDATA[P1-P0 < -20Pa, the amount of cold air drawn into the electric arc furnace is excessively large, resulting in an excessively low flue gas temperature inside the furnace]]> <![CDATA[Q1 is too large, Q2 is too large]]> Excessive cold air volume at the scrap steel loading point and inside the electric arc furnace resulted in excessively low flue gas outlet temperature (less than 1100℃). <![CDATA[Q1 is excessively small, Q2 is excessively small]]> High-temperature flue gas overflowed from the electric arc furnace, and the flue gas outlet temperature was too high (greater than 1200℃). <![CDATA[Q1 is moderate, Q2 is moderate]]> <![CDATA[-20Pa<P1-P0<-10Pa, the flue gas temperature (in the range of 1100-1200°C) in the scrap preheating shaft and the electric arc furnace is well controlled]]>

[0040] The following specific embodiments illustrate the effects of using the steelmaking apparatus of this invention for steelmaking.

[0041] Taking a 150t electric arc furnace as an example, during continuous production, a disk crane is used to feed scrap steel into a chain conveyor. The chain conveyor has a maximum feeding capacity of 600t / h, and the horizontal angle between the chain conveyor and the ground is 38° to ensure that the scrap steel can continuously move upwards without slipping. After passing through the inclined section of the chain conveyor, the scrap steel enters the horizontal section, passes through the dynamic sealing component, and then falls into the closed water-cooled finger via a buffer slide. After 4 minutes of continuous feeding, the weight of the scrap steel above the water-cooled finger reaches 40t, at which point the chain conveyor stops working. The scrap steel in the vertical shaft begins to enter the centralized preheating stage. After being preheated by the high-temperature flue gas generated in the electric arc furnace, the preheating temperature reaches 700℃ after 4 minutes. At this time, the water-cooled finger opens, and the preheated scrap steel falls into the furnace to start the smelting of this batch. After three repeated feeding and preheating cycles, feeding for this batch stops, and the steel tapping operation is completed after smelting. After adjustment, the Q1 setting range during the smelting process is 80000~90000Nm. 3 / h, Q2 is set within the range of 200000~220000Nm 3 At this time, P1-P0 is between -15Pa and -12Pa, and the electric arc furnace is under a slight negative pressure. Simultaneously, the flue gas outlet temperature is 1150~1180℃, and there is no overflow of high-temperature flue gas inside the electric arc furnace. Table 2 shows the technical and economic indicators for this heat run. Compared with traditional processes, all economic and technical indicators have reached industry-leading levels, indicating that the scrap steel preheating effect has reached an excellent state.

[0042] Table 2: Technical and Economic Indicators of 120t Electric Furnace

[0043] project Indicator value Scrap steel addition amount / t 120 Steel output / t 114 Melting time / min 31 Power-on time / min 25 Electricity consumption per ton of steel / kWh·t-1 310 Oxygen consumption / Nm3·t-1 25 Toner consumption / kg·t⁻¹ 13 Electrode consumption / kg·t⁻¹ 0.85

[0044] The above examples are merely illustrative of the present invention and do not constitute a limitation on the scope of protection of the present invention. All designs that are the same as or similar to the present invention are within the scope of protection of the present invention.

Claims

1. A steelmaking apparatus with scrap preheating function, characterized in that: The system includes a scrap steel conveying assembly, a scrap steel preheating shaft, and an electric arc furnace. The output end of the scrap steel conveying assembly is connected to the scrap steel inlet of the scrap steel preheating shaft, and the scrap steel outlet of the scrap steel preheating shaft is connected to the scrap steel inlet of the electric arc furnace. The scrap steel preheating shaft is equipped with water-cooled fingers, and a dynamic sealing assembly is provided at the connection between the scrap steel conveying assembly and the scrap steel preheating shaft to prevent flue gas from escaping from the scrap steel preheating shaft and external cold air from entering the scrap steel preheating shaft.

2. The steelmaking apparatus with scrap preheating function as described in claim 1, characterized in that: The dynamic sealing assembly includes a sealing cover, a first variable frequency fan, and movable baffles. The sealing cover covers the top of the scrap steel preheating shaft. The end of the scrap steel conveying assembly extends into the sealing cover. The first variable frequency fan is mounted on the sealing cover. There are two sets of movable baffles, spaced apart along the scrap steel running direction. The upper end of the movable baffle is rotatably connected to the sealing cover, and the lower end of the movable baffle contacts the surface of the scrap steel conveying assembly. The sealing cover, movable baffles, and the end of the scrap steel conveying assembly enclose a closed space, and the first variable frequency fan is connected to this closed space.

3. The steelmaking apparatus with scrap preheating function as described in claim 2, characterized in that: A second variable frequency fan is installed at the flue gas outlet at the top of the scrap steel preheating shaft, and the second variable frequency fan is interlocked with the first variable frequency fan.

4. The steelmaking apparatus with scrap preheating function as described in claim 2, characterized in that: Each set of movable baffles is composed of several blocks seamlessly assembled side by side along a direction perpendicular to the scrap steel running direction, with the upper ends of each block rotatably connected to the same rotating shaft.

5. The steelmaking apparatus with scrap preheating function as described in claim 4, characterized in that: The stop block has a wedge-shaped structure, with the thinner end of the wedge connected to the rotating shaft.

6. The steelmaking apparatus with scrap preheating function as described in claim 1, characterized in that: A temperature sensor is installed at the flue gas outlet at the top of the scrap steel preheating shaft.

7. The steelmaking apparatus with scrap preheating function as described in claim 1, characterized in that: The scrap steel conveying assembly includes a chain conveyor with an inclined section and a horizontal section connected in sequence. The horizontal section is connected to the scrap steel inlet at the top of the scrap steel preheating shaft, and the dynamic sealing assembly is arranged on the horizontal section.

8. The steelmaking apparatus with scrap preheating function as described in claim 7, characterized in that: The angle α between the inclined section and the horizontal plane is 35-40°.

9. The steelmaking apparatus with scrap preheating function as described in claim 1, characterized in that: A buffer slide is provided between the scrap steel conveying assembly and the scrap steel inlet of the scrap steel preheating shaft.

10. The steelmaking apparatus with scrap preheating function as described in claim 1, characterized in that: The water-cooled finger is equipped with a pressure sensor, and the pressure sensor is interlocked with the scrap steel conveying assembly.

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