Thermal-state direct reduction iron conveying device and method

Abstract

The invention discloses a hot-state direct reduction iron conveying device and method, and belongs to the technical field of ferrous metallurgy material conveying. The hot-state direct reduction iron conveying device comprises a closed material tank and a material tank discharging device, and the closed material tank is matched with a shaft furnace discharging device and used for containing and transferring hot-state direct reduction iron; and the charging bucket unloading device is matched with the closed charging bucket and is used for unloading the hot-state direct reduction iron in the closed charging bucket into the electric furnace buffer device. The hot-state direct reduction iron conveying method is not limited by a general drawing and the distance between the electric furnace and the shaft furnace, the process route can be planned at will, the whole process is almost carried out in a closed environment, the temperature drop of the direct reduction iron mainly comes from heat dissipation of the charging bucket, the heat loss is very small, and compared with the prior art, the method has the advantages that the cost is low; the temperature of the direct reduction iron heat fed into the electric furnace is increased, the power consumption is greatly saved, and the purposes of cleaning energy, increasing sources and reducing throttling are thoroughly achieved.

Description

Technical Field

[0001] This invention belongs to the field of material conveying technology in iron and steel metallurgy, and particularly relates to a hot direct reduced iron conveying device and method. Background Technology

[0002] Direct reduced iron (DRI) is a metallic iron product produced through non-blast furnace ironmaking processes. Due to its high purity, stable quality, and excellent metallurgical properties, DRI has become an indispensable raw material for producing high-quality and pure steel. It is mainly used as a raw material in electric arc furnace steelmaking and can also be used as a coolant in converter steelmaking.

[0003] Currently, the mainstream direct reduced iron (DRI) processes worldwide typically produce DRI at temperatures around 600℃. Production practice shows that for every 100℃ increase in the DRI hot-feeding furnace temperature, 20-40 kWh / t of electricity can be saved. At 700℃, electricity savings exceed 150 kWh / t. Furthermore, experiments conducted by foreign technical personnel have verified that at 600℃, electricity savings reach 124-125 kWh / t, while electrode consumption decreases by approximately 0.03 kg / t.

[0004] Currently, the two most mature hot direct reduced iron (DRI) conveying technologies internationally are hot chain conveyor technology and pneumatic conveyor technology. Each technology has its own characteristics. Hot chain conveyor technology, due to its reliance on conveyors, has strict requirements on the overall layout and relative positions of the shaft furnace and electric furnace, preventing arbitrary arrangement. Furthermore, because the conveyed material is a high-temperature, easily oxidized substance, it places high demands on the high-temperature resistance and sealing of the mechanical equipment, often leading to high-temperature deformation and aging. While pneumatic conveyor technology offers more flexible layout, it relies on high-pressure nitrogen as the conveying medium, thus requiring a certain distance between the shaft furnace and electric furnace, typically not exceeding 200 meters. Additionally, due to the high hardness of hot DRI, the conveying pipes are easily worn down and even leak under the high-speed material flow, resulting in a shorter overall lifespan and higher replacement costs.

[0005] Therefore, it is imperative to develop a hot transport method that is not limited by distance or overall layout, can withstand high temperatures, and has a long service life. In addition, when selecting hot charging for direct reduced iron into the furnace, maximizing the temperature of the direct reduced iron charged into the electric furnace will bring considerable economic and social benefits to enterprises and greatly reduce production costs.

[0006] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0007] To address the technical problems of hot direct reduced iron (DRI) conveying being limited by site and distance, and also suffering from significant heat loss, this paper provides a hot DRI conveying device and method.

[0008] The first aspect of this invention provides a hot direct reduced iron conveying device, comprising a closed material tank and a material tank unloading device, wherein, A closed material tank, which works in conjunction with the vertical furnace unloading device, is used to hold and transfer hot direct reduced iron; The unloading device for the material tank, which works in conjunction with the closed material tank, is used to unload the hot direct reduced iron in the closed material tank into the electric furnace buffer device.

[0009] In one embodiment, the enclosed material tank includes a tank body, a material bell, and a material base, wherein the material bell is welded to the material base; The tank body is provided with an upper opening at the top and a lower opening at the bottom; The upper tank opening is equipped with a top gate for closing the upper tank opening; The feed bell is matched with the lower can opening to seal the lower can opening.

[0010] In one embodiment, the top gate is equipped with a guide roller assembly for controlling the opening and closing of the top gate; the guide roller assembly includes a hydraulic unit, ropes, and a roller assembly, the roller assembly being controlled by the hydraulic unit.

[0011] In one embodiment, the guide roller assembly further includes a counterweight.

[0012] In one embodiment, the material tank body is provided with a lifting frame, which includes a lifting beam, a tie rod, a material bell and a bell base. The upper part of the tie rod is connected to the lifting beam, and the lower part of the tie rod is connected to the bell base.

[0013] In one embodiment, the material tank body is provided with a passivation device for providing inert gas into the material tank body.

[0014] In one embodiment, the outer wall of the material tank body is provided with a plurality of brackets for assisting in fixing the material tank body.

[0015] In one embodiment, the unloading device for the material tank includes a bottom hopper and a tank support. The bottom of the tank support is fixed to the bottom hopper, and the top of the tank support is provided with a groove that mates with the bracket.

[0016] A second aspect of the present invention provides a method for hot direct reduced iron transport, comprising: S1: The high-temperature hot direct reduced iron generated by the vertical furnace falls into the vertical furnace unloading system; S2: When the lower part of the vertical furnace unloading system is ready for unloading, the guide roller group located at the top of the sealed tank automatically rotates to open the top valve. At the same time, the passivation device outside the sealed tank opens and inert gas is introduced into the tank to maintain a slight positive pressure inside the tank. At this time, the hot valve at the bottom of the vertical furnace unloading system opens and hot direct reduced iron begins to fall into the tank. When the tank is full of hot direct reduced iron, the guide roller group rotates in the reverse direction and closes the top valve. S3: Transport and lift the material to the top of the unloading device of the tank; S4: Loosen the lever, and the material inside the tank will move downward under the action of gravity, causing the bell and bell base at the bottom of the tank to move downward, opening the sealed bottom of the tank and realizing unloading.

[0017] In one embodiment, the unloading conditions are that the material level in the buffer hopper is not less than two-thirds and the closed material tank has issued a positioning signal.

[0018] Compared with existing technologies, the technical effects achieved by this invention are as follows: (1) The hot direct reduced iron conveying method of the present invention is not limited by the general layout and the distance between the electric furnace and the vertical furnace. The process route can be planned arbitrarily. The entire process is almost carried out in a closed environment. The temperature drop of direct reduced iron mainly comes from the heat dissipation of the material tank itself. The heat loss is very small. Compared with the prior art, the temperature of direct reduced iron hotly delivered into the electric furnace is increased, which greatly saves electricity consumption and completely achieves the purpose of clean energy, opening up new sources of energy and saving money.

[0019] (2) The system of the present invention has a simple process, good adaptability and flexibility, can maximize the use of the existing logistics facilities system of steel enterprises, requires less engineering investment, has reliable performance, low equipment failure rate, and greatly reduces maintenance costs. It is worth promoting to various enterprises. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the hot direct reduction iron transport process in one embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the enclosed material tank in one embodiment of the present invention; Figure 3 This is a schematic diagram of the tank valve roller assembly structure (gate closed state) in one embodiment of the present invention; Figure 4 This is a schematic diagram of the tank valve roller assembly structure (gate open state) in one embodiment of the present invention; Figure 5 This is a schematic diagram of the process of the tank valve opening from closed to open in one embodiment of the present invention; Figure 6This is a schematic diagram of the process of the tank valve from opening to closing in one embodiment of the present invention; Figure 7 This is a schematic diagram of the structure of the material tank unloading device in one embodiment of the present invention; Figure 8 This is a schematic diagram of the combined structure of the enclosed material tank and the material tank unloading device in one embodiment of the present invention; In the diagram: 1-Lifting beam; 2-Tie rod; 3-Tank body; 4-Cabinet; 5-Bell; 6-Bell base; 7-Top gate; 8-Guide roller assembly; 801-Hydraulic unit; 802-Rope; 803-Roller assembly; 804-Counterweight; 9-Passivation device; 10-Upper tank opening; 11-Tank support; 1101-Groove; 12-Bottom hopper. Detailed Implementation

[0021] The technical solution of the present invention will be described below with reference to the accompanying drawings and specific embodiments. It should be understood that the existence of other methods and steps before and after the combined steps, or the insertion of other methods and steps between these explicitly mentioned steps, does not preclude the use of one or more steps mentioned in the present invention. It should also be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise stated, the numbering of each method step is for the purpose of identifying each method step, and is not intended to limit the order of each method or limit the scope of the invention. Changes or adjustments to their relative relationships, without substantial changes to the technical content, can also be considered within the scope of the invention.

[0022] The raw materials and instruments used in the examples are not subject to any specific restrictions on their source; they can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0023] A hot direct reduced iron (DRI) conveying device mainly includes a vertical shaft furnace unloading system, a closed material tank, a material tank transport system, a material tank lifting and lateral movement system, a material tank unloading device, and an electric arc furnace buffer system. In one embodiment, the vertical shaft furnace unloading system is located at the bottom of the vertical shaft furnace and mainly includes a buffer bin, a discharge pipe, and several hot valves. The discharge pipe and valves are all high-temperature and wear-resistant equipment. The buffer bin has a refractory-lined structure, which can effectively prevent heat loss. The material tank transport system includes truck transport or train transport, and the specific transport method depends on the arrangement and positional relationship between the electric arc furnace and the vertical shaft furnace, as well as the logistics conditions of the steel enterprise. Existing logistics systems in steel companies can typically be utilized. To maintain the stability of the material tanks, transport vehicles are often equipped with onboard supports fixed to the vehicles for placing the tanks. These onboard supports are rigid structures with grooves. The material tank lifting and translating system mainly consists of a main structural frame, lifting mechanism, translating mechanism, lifting gear, lubrication system, and auxiliary safety system. This system can utilize the company's existing lifting facilities, minimizing initial project investment. The electric furnace buffer system is similar to the vertical shaft furnace unloading system, mainly including a buffer hopper, discharge pipe, and related valves. The vertical shaft furnace unloading system, material tank transport system, material tank lifting and translating system, and electric furnace buffer system can all utilize existing conventional configuration systems.

[0024] like Figure 2 As shown, the enclosed material tank, which works in conjunction with the vertical furnace unloading device, is used to hold and transfer hot direct reduced iron, including the material tank body 3, the material bell 5, and the material base 6; The unloading device for the material tank, which works in conjunction with the closed material tank, is used to unload the hot direct reduced iron in the closed material tank into the electric furnace buffer device.

[0025] In one embodiment, the bell 3 is welded to the material base 6, the top of the material tank body is provided with an upper tank opening 10, and the bottom is provided with a lower tank opening. The upper tank opening is provided with a top gate 7 for closing the upper tank opening 10; the bell 5 is matched with the lower tank opening for sealing the lower tank opening.

[0026] In one embodiment, the top gate 7 is equipped with a guide roller assembly 8 for controlling the opening and closing of the top gate 7. For example... Figure 3 , Figure 4 As shown, the guide roller assembly 8 includes a hydraulic unit 801, a rope 802, and a roller assembly 803. The rope 802 passes around the roller assembly and is connected to both ends of the hydraulic unit 801. The rotation of the rope 802 around the roller assembly is controlled by the hydraulic unit 801.

[0027] Figure 5 (a), 5(b), and 5(c) are schematic diagrams of the process of the tank valve from closed, half-open, to fully open. When the instruction to open the valve is received, the hydraulic unit 801 drives the rope 802 to rotate clockwise around the roller group 803, pulling the top valve 7 to one side and opening the valve. Figure 6 (a), 6(b), and 6(c) are schematic diagrams of the process of the tank valve from closed, half closed, to fully closed. When the tank is filled with hot direct reduced iron, the hydraulic unit 801 rotates in reverse, driving the rope 802 to rotate counterclockwise around the roller group 803, pulling the top valve 7 back to the top of the tank opening and closing the top valve 7.

[0028] Under normal conditions, the valve is opened and closed by the hydraulic unit 801 driving the rope 802. The guide roller assembly 8 also includes a counterweight 804. In case of a hydraulic system failure, the valve is closed by the counterweight 804. Specifically, when the top valve 7 is open, pulling the counterweight 804 downward causes the rope 802 to rotate counterclockwise around the roller assembly 803, thereby moving the top valve 7 downward and closing the valve. When the top valve 7 is closed, pulling the counterweight 804 in the opposite direction causes the rope 802 to rotate clockwise around the roller assembly 803, thereby moving the top valve 7 upward and opening the top valve 7.

[0029] In one embodiment, the material tank body 3 is provided with a lifting frame on its exterior. The lifting frame includes a lifting beam 1 and tie rods 2. The upper part of the tie rod 2 is connected to the lifting beam 1, and the lower part of the tie rod 2 is connected to the bell base 6. Generally, any connection method that can ensure a firm connection is acceptable, with pin connections being preferred. There are generally no fewer than four tie rods 2, evenly distributed around the material tank body 3. That is, when the sealed material tank is hoisted, the material tank body 3 is suspended by no fewer than four tie rods 2. When there are four tie rods 2, each tie rod 2 can bear one-quarter of the load, and the corresponding pin of each tie rod 2 also bears one-quarter of the load. Pins with sufficient strength are used.

[0030] In one embodiment, a passivation device 9 is provided outside the material tank body 3 to provide inert gas into the material tank body 3 to ensure a slightly positive pressure state inside the material tank. This is because hot direct reduced iron has the risk of re-oxidation, so it is necessary to continuously introduce inert protective gas into the tank to maintain a slightly positive pressure inside the tank, thereby ensuring that the hot direct reduced iron does not come into contact with air.

[0031] In one embodiment, the outer wall of the material tank body 3 is provided with a plurality of brackets 4 to assist in fixing the material tank body 3.

[0032] In one embodiment, such as Figure 7 As shown, the material tank unloading device includes a bottom hopper 12 and a tank support 11. The bottom of the tank support 11 is fixed to the bottom hopper 12, and the top of the tank support 11 is provided with a groove 1101 that cooperates with the bracket 4.

[0033] In one embodiment, after the sealed tank is placed in the tank unloading device, there is a certain space between the bottom of the bell base 6 and the bottom hopper 12. This space not only does not hinder the sinking of the bell 5 and the bell base 6, but also prevents the bell 5 and the bell base 6 from blocking the outlet 12 of the bottom hopper, allowing the hot direct reduced iron in the tank body 3 to flow out smoothly and enter the electric furnace buffer system through the bottom hopper 12. The combined state of the sealed tank and the tank unloading device is as follows: Figure 8 As shown.

[0034] like Figure 1 As shown, a method for hot direct reduced iron transport includes: S1: The high-temperature hot direct reduced iron generated by the vertical furnace falls into the vertical furnace unloading system under the action of gravity; S2: When the lower part of the vertical furnace unloading system meets the unloading conditions, that is, the unloading conditions are that the material level in the buffer bin is not less than two-thirds and the closed material tank has issued a positioning signal, the guide roller group 8 located at the top of the closed material tank automatically rotates to open the top valve 7. At the same time, the passivation device 9 outside the closed material tank is opened, and inert gas is injected into the tank to maintain a slight positive pressure inside the tank. At this time, the hot valve at the lower part of the vertical furnace unloading system opens, and hot direct reduced iron begins to fall into the tank. When the hot direct reduced iron in the tank is full, the guide roller group 8 rotates in the reverse direction and closes the top valve 7. S3: Transport and lift to the top of the tank unloading device. Specifically, the closed tank filled with hot direct reduced iron is placed on the transport vehicle of the tank transport system under the action of the lifting equipment. The closed tank is transported to the vicinity of the tank lifting and translation system in the steelmaking electric furnace workshop. Under the action of the tank lifting and translation system, the tank filled with hot direct reduced iron is lifted to the upper height of the tank unloading device. Then, the closed tank is slowly moved to the top of the tank unloading device. After reaching the appropriate height, the bracket 4 on the tank body 3 is slowly matched with the groove 1101 on the tank support 11 under the action of the lifting mechanism. S4: Slowly lower the lifting mechanism. The pull rod 2 located on the tank body 3 is no longer subjected to upward pulling force. Under the action of gravity, the material in the tank causes the 2 material bells 5 and bell bases 6 at the bottom of the tank to move downward. The closed bottom of the tank is opened to achieve unloading. The hot direct reduced iron falls into the electric furnace buffer system. S5: According to the production rhythm, the hot direct reduced iron in the electric furnace buffer system is periodically charged to the lower electric furnace to complete the entire hot direct reduced iron conveying process.

[0035] Meanwhile, the unloaded tank completes one discharge and returns to the standby position through the combined action of the tank horizontal lifting system and the tank transportation system.

[0036] After unloading, simply pull up the lifting beam 1 and the pull rod 2 to drive the bell 5 and the bell base 6 to close in conjunction with the material tank.

[0037] During transportation, the sealed container is placed on the vehicle's mounting bracket. Although the tie rod is not under stress during transportation, the height of the mounting bracket prevents the lower part of the container from being suspended in the air, thus preventing the lower bell base and bell from opening and causing leakage.

[0038] Since the entire process of this invention is carried out in a closed environment, the temperature drop of direct reduced iron mainly comes from the heat dissipation of the material tank itself. Taking a calculated material tank movement distance of less than 500m and an initial direct reduced iron temperature of 600℃ as an example, using the transportation device and method provided by this invention, the temperature drop of direct reduced iron is within 50℃, that is, the temperature of direct reduced iron fed into the electric furnace is about 550℃, which can save 120kWh / t of electricity.

[0039] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A hot direct reduced iron conveying device, characterized in that, Includes enclosed material tanks and material tank unloading devices, among which, A closed material tank, which works in conjunction with the vertical furnace unloading device, is used to hold and transfer hot direct reduced iron; The unloading device for the material tank, which works in conjunction with the closed material tank, is used to unload the hot direct reduced iron in the closed material tank into the electric furnace buffer device.

2. The hot direct reduced iron conveying device according to claim 1, characterized in that, The enclosed material tank includes a tank body, a material bell, and a material base, with the material bell welded onto the material base; The tank body is provided with an upper opening at the top and a lower opening at the bottom; The upper tank opening is equipped with a top gate for closing the upper tank opening; The feed bell is matched with the lower can opening to seal the lower can opening.

3. The hot direct reduced iron conveying device according to claim 2, characterized in that, The top gate is equipped with a guide roller assembly for controlling the opening and closing of the top gate; The guide roller assembly includes a hydraulic unit, a rope, and a roller assembly, and the rotation of the rope is controlled by the hydraulic unit.

4. The hot direct reduced iron conveying device according to claim 3, characterized in that, The guide roller assembly also includes a counterweight.

5. The hot direct reduced iron conveying device according to claim 2, characterized in that, The material tank body is provided with a lifting frame on the outside. The lifting frame includes a lifting beam, a tie rod, a material bell and a bell base. The upper part of the tie rod is connected to the lifting beam, and the lower part of the tie rod is connected to the bell base.

6. The hot direct reduced iron conveying device according to claim 2, characterized in that, The material tank body is provided with a passivation device for providing inert gas into the material tank body.

7. The hot direct reduced iron conveying device according to claim 2, characterized in that, The outer wall of the material tank body is provided with several brackets to help fix the material tank body.

8. The hot direct reduced iron conveying device according to claim 7, characterized in that, The material tank unloading device includes a bottom hopper and a tank support. The bottom of the tank support is fixed to the bottom hopper, and the top of the tank support is provided with a groove that cooperates with the bracket.

9. A method for conveying hot direct reduced iron, characterized in that, include: S1: The high-temperature hot direct reduced iron generated by the vertical furnace falls into the vertical furnace unloading system; S2: When the lower part of the vertical furnace unloading system is ready for unloading, the guide roller group located at the top of the sealed tank automatically rotates to open the top valve. At the same time, the passivation device outside the sealed tank opens and inert gas is introduced into the tank to maintain a slight positive pressure inside the tank. At this time, the hot valve at the bottom of the vertical furnace unloading system opens and hot direct reduced iron begins to fall into the tank. When the tank is full of hot direct reduced iron, the guide roller group rotates in the reverse direction and closes the top valve. S3: Transport and lift the material to the top of the unloading device of the tank; S4: Loosen the lever, and the material inside the tank will move downward under the action of gravity, causing the bell and bell base at the bottom of the tank to move downward, opening the sealed bottom of the tank and realizing unloading.

10. The direct reduced iron conveying method according to claim 9, characterized in that, The unloading conditions are that the material level in the buffer hopper is not less than two-thirds and the closed material tank has issued a positioning signal.

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