Controllable flow blast furnace device and smelting method

Abstract

The application provides a blast furnace device with controllable flow and separated cavities and a smelting method, which comprises a lower furnace body, a preheating chamber, a furnace cover and an electrode assembly. The lower furnace body has a melting separation pool. The upper furnace body is provided with a material stacking space extending longitudinally from the preheating chamber to the melting separation pool. The electrode assembly extends into the lower furnace body through the furnace cover. A hot air outlet is arranged at the lower part of the preheating chamber and used for sending hot air into the lower part of the material stacking space to heat the material accumulated in the material stacking space. A material blocking mechanism is installed on the side wall of the preheating chamber and divides the material stacking space into upper and lower parts. The material blocking mechanism is driven by a driving mechanism to act and release the material. An air outlet is arranged at the upper part of the preheating chamber and used for discharging the heat-exchanged flue gas. The material stacking space simultaneously serves as a channel for the upward dispersion of the electric arc smelting flue gas and the hot air to the air outlet. In the material smelting process, the application replaces electric energy with part of the chemical energy of the hot air to reduce the consumption of electricity, thereby achieving emission reduction and improving economic benefits.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical technology, and in particular relates to a controllable material flow caving electric furnace device and smelting method. Background Technology

[0002] Under the low-carbon context, the steel industry faces enormous pressure to reduce carbon emissions. Furthermore, resource constraints pose even greater challenges to energy conservation and emission reduction in the steel sector. Currently, the typical carbon reduction technology path for the steel industry, avoiding blast furnaces, is: hydrogen-based (or gas-based) shaft furnace - reduced iron - electric arc furnace steelmaking process. However, this process is constrained by global refined iron ore resources and ore grade. The reduced iron produced by shaft furnaces generally has an iron content of only about 80%, which poses a significant challenge to the subsequent electric arc furnace steelmaking process, leading to a sharp increase in power consumption. The theoretical power consumption for smelting this type of reduced iron is as high as approximately 700 kWh / t (considering furnace thermal efficiency), or even higher. How to smelt low-quality direct reduced iron in a low-cost, green, and low-carbon manner has become a major challenge.

[0003] To achieve low-cost, low-carbon smelting of low-quality direct reduced iron, reducing power consumption is the preferred approach.

[0004] 1) The conversion of fuel thermal energy into electrical energy currently has an average efficiency of about 40% in China. After considering the power transmission loss (90%) and the heat transfer efficiency of the electric furnace (generally 50%-70%), the energy transfer path through fuel calorific value-electric energy-metal heat is: metal heat / fuel calorific value*100%=21.6%. In other words, the total energy efficiency of the electric furnace process through current transfer is about 21.6%.

[0005] This data also shows that a furnace with a chemical energy conversion efficiency of more than 30% to metal heat has an energy-saving effect when the portion of electrical energy is replaced by chemical energy.

[0006] 2) Considering that domestic electricity is mainly generated by coal-fired power plants, the electric arc furnace smelting of low-quality direct reduced iron with high gangue content not only results in high power consumption but also increases carbon emissions in the process. If green energy (such as natural gas, CH4, H2) is used as the chemical energy source, the improvement in energy type and efficiency will greatly reduce carbon emissions in the steelmaking process (as in the Middle East, where natural gas is abundant).

[0007] 3) Currently, vertical shaft scrap preheating electric arc furnaces worldwide use vertical shaft charging or stacking for material feeding. Their advantage is high thermal efficiency, but their disadvantage is that the molten pool cannot be completely dissolved, and there is always a solid-liquid interface. When used for smelting of molten iron with a high proportion of straight ring iron, the temperature of the molten metal is uneven, which can easily lead to metal loss during slag removal and reduce the metal yield.

[0008] Alternatively, a concentrated batch feeding method can be used, resulting in an explosive accumulation of materials in the molten pool. This impacts the molten pool, power grid, dust removal system, electrodes, and noise levels, creating a discontinuous and unstable smelting environment, increasing the difficulty of operation and the likelihood of equipment failure.

[0009] If the material flow can be controlled in the vertical shaft feeding process according to the material characteristics, the smelting conditions, production environment, electromagnetic radiation, and noise radiation will be greatly improved. Summary of the Invention

[0010] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a controllable material flow blast furnace device that uses part of the hot air chemical energy to replace electrical energy during the smelting process, thereby reducing electricity consumption, lowering smelting costs, and simultaneously achieving material flow control.

[0011] To achieve the above and other related objectives, the technical solution of the present invention is as follows:

[0012] A controllable material flow blast furnace device includes:

[0013] The lower furnace body has a melting pool, and a slag outlet and a molten metal outlet are provided on the lower furnace body;

[0014] An upper furnace body is installed on a lower furnace body. The upper furnace body includes at least one preheating chamber and is provided with a material stacking space that extends longitudinally from the preheating chamber to the melting pool. Material can flow from the material stacking space to the melting pool.

[0015] The furnace cover is installed on the lower or upper furnace body and together with the upper and lower furnace bodies, it forms a smelting preheating space.

[0016] The electrode assembly extends into the lower furnace body after passing through the furnace cover;

[0017] The material flow control device includes a material blocking mechanism and a drive mechanism for driving the material blocking mechanism to release material. The material blocking mechanism is located in the lower part of the preheating chamber and divides the material stacking space into upper and lower parts. The space above the material blocking mechanism is the upper space, and the space from the material blocking mechanism to the melting pool is the lower space. The material blocking mechanism has a venting gap.

[0018] A hot air inlet is located at the lower part of the upper furnace body and is used to send hot air into the stacking space;

[0019] The air outlet is located at the top of the preheating chamber;

[0020] The material stacking space also serves as an exhaust channel for the electric arc melting fumes and hot air to diffuse upwards to the air outlet, and the fumes and / or hot air can rise from the lower space, pass through the baffle mechanism, and enter the upper space.

[0021] In one embodiment of the present invention, the number of preheating chambers is one, or the number of preheating chambers is two or more, and each preheating chamber has at least one set of material flow control devices.

[0022] In one embodiment of the present invention, the lower furnace body is circular, and two or more preheating chambers are arranged at intervals along the circumference of the lower furnace body.

[0023] In one embodiment of the present invention, the lower furnace body is elongated, and multiple preheating chambers are arranged along the length of the lower furnace body.

[0024] In one embodiment of the present invention, the furnace cover and electrode assembly are located on one side of the preheating chamber; or there are two or more preheating chambers, and the furnace cover and electrode assembly are located between the preheating chambers.

[0025] In one embodiment of the present invention, the preheating chamber or material storage space has a rectangular cross-section.

[0026] In one embodiment of the present invention, the material blocking mechanism has a comb-like structure, including a main support beam and multiple parallel and spaced material blocking arms connected to the main support beam. The gap between the material blocking arms forms the air-permeable gap, and the material blocking arms extend into the material storage space to block the material.

[0027] In one embodiment of the present invention, the driving mechanism includes a first driving mechanism, and the material blocking mechanism can be driven by the first driving mechanism to at least partially extend into or out of the material stacking space in order to control the material flow;

[0028] And / or, the driving mechanism includes a second driving mechanism for driving the material stop mechanism to vibrate, thereby controlling the material flow by driving the material stop mechanism to vibrate and feed material.

[0029] In one embodiment of the present invention, the vibration direction of the material blocking mechanism is transverse or longitudinal.

[0030] In one embodiment of the present invention, a weighing device is provided on the material flow control device.

[0031] In one embodiment of the present invention, the hot air vent is located above or below the material blocking mechanism.

[0032] In one embodiment of the present invention, the controllable material flow baffled blast electric furnace device further includes a hot air generating device and a hot air ring pipe. The upper furnace body is provided with a plurality of hot air inlets at intervals along the circumference. Each hot air inlet is connected to the hot air ring pipe, and the hot air ring pipe is connected to the hot air generating device.

[0033] In one embodiment of the present invention, a plurality of burners for blowing air into the furnace are arranged at intervals along the circumference of the lower part of the upper furnace body; or the hot air inlet is replaced with burners.

[0034] In one embodiment of the present invention, each of the preheating chambers is provided with a feeding device on the top of the furnace, the air outlet is located on the side or top of the upper part of the preheating chamber, and the air outlet is higher than the top of the material storage space.

[0035] In one embodiment of the present invention, the furnace cover or the upper furnace body is provided with a nozzle for spraying carbon powder onto the preheated material.

[0036] This invention proposes a smelting method using the aforementioned controllable material flow blast furnace device:

[0037] The lower furnace body maintains a portion of the molten pool;

[0038] The material blocking mechanism separates the upper and lower spaces, allowing material to be added into the preheating chamber. The material then accumulates upwards in the upper space of the preheating chamber from the material blocking mechanism.

[0039] High-temperature hot air is blown into the preheating chamber through the hot air vent to preheat at least the material above the baffle mechanism.

[0040] In the lower furnace body, the electric arc and hot air work together to heat and melt the material below the baffle mechanism. The molten metal formed after the material melts sinks to the bottom of the lower furnace body, while the slag layer floats on top of the molten metal.

[0041] Depending on the degree of smelting, the material feeding mechanism is driven to continuously or intermittently discharge material, causing the material to fall into the lower space and the lower furnace body;

[0042] The flue gas and hot air diffuse upward through the gaps between the materials, preheating the materials in the stacking space, and are discharged from the air outlet after heat exchange.

[0043] When the liquid level reaches the set position, the slag liquid is discharged from the slag outlet, and the molten metal is discharged from the molten metal outlet of the lower furnace body.

[0044] In one embodiment of the present invention, the material flow rate is controlled by controlling the movement of the material blocking mechanism as it extends into or out of the preheating chamber.

[0045] Alternatively, the material can be discharged by driving the material-blocking mechanism to vibrate, and the material falls through the air gap of the material-blocking mechanism;

[0046] Alternatively, material flow can be controlled by combining the insertion or withdrawal of the material stop mechanism into or out of the preheating chamber with the vibration of the material stop mechanism.

[0047] This invention proposes a smelting method using a controllable cavitary blast furnace device: there are two or more preheating chambers, and each preheating chamber is alternately fed to the furnace body at fixed points, and the material flow is controlled by a baffle mechanism during the feeding process.

[0048] As described above, the beneficial effects of the present invention are as follows: the material blocking mechanism divides the material storage space into upper and lower parts. During smelting, high-temperature hot air is injected from the hot air vent to heat the material in the area from the hot air vent to the top of the material storage. The electrode assembly is smelted by electric arc in the melting pool. As the material piled below and around the material blocking mechanism gradually melts, the slag and liquid are clearly separated after reaching a certain liquid level. The material in the material storage space above the material blocking mechanism is blocked by the material blocking mechanism. Hot air / flue gas penetrates the gap of the material blocking mechanism to preheat the upper material. The material can be discharged according to the melting status of the material below the material blocking mechanism.

[0049] Hot air penetrates the material from the bottom of the preheating chamber and diffuses upwards, while the material descends and exchanges heat fully. Since the material stacking space is also partially or entirely used as a flue gas exhaust channel, the smelting flue gas and hot air exchange heat with the material during the upward exhaust process. The counter-current heat transfer of the material and hot air flow improves the heat utilization efficiency.

[0050] In the material smelting process, some of the hot air chemical energy is used to replace electrical energy, reducing electricity consumption and thus achieving emission reduction and improved economic efficiency. The baffle mechanism supports and preheats the material in the upper space, and reduces the amount of raw materials or metal elements carried away by the slag liquid during slag discharge, thereby improving metal recovery, increasing economic efficiency, and reducing emissions. Attached Figure Description

[0051] Figure 1 A schematic diagram of the structure of a controllable material flow blast furnace device (DC) is shown in one embodiment.

[0052] Figure 2 for Figure 1 Top view;

[0053] Figure 3 This is a schematic diagram of the material flow control device in one embodiment;

[0054] Figure 4 This is a schematic diagram of the structure of another embodiment of a controllable material flow blast furnace device (AC).

[0055] Figure 5 for Figure 4 A top view (excluding the hot air generator and dust removal pipe);

[0056] Figure 6 This is a schematic diagram of the structure of a dual-furnace body controllable baffled blast electric furnace device (DC) according to another embodiment;

[0057] Figure 7 for Figure 6 Top view (excluding hot air generator, dust removal pipe, and circulation bypass);

[0058] Figure 8 This is a schematic diagram showing the layout of the three and four preheating chambers in the embodiment;

[0059] Figure 9 This is a schematic diagram of the preheating chamber layout of the preheating chamber controllable baffled blast electric furnace device in Example 6;

[0060] Figure 10 This is a schematic diagram of the main view of a multi-preheating chamber controlled material flow blast furnace device (with material bins) as an example.

[0061] Figure 11 This is a schematic diagram of the preheating chamber layout and flue gas circulation of a multi-preheating chamber controlled material flow baffled blast electric furnace device in an embodiment.

[0062] Figure 12 This is a schematic diagram illustrating the use of a burner to replace the hot air inlet or the installation of a burner inside the hot air inlet in the embodiment.

[0063] Figure 13 This is a schematic diagram of the heat conduction model on the surface of a traditional electric furnace burner.

[0064] Figure 14 This is a schematic diagram of the hot air heat transfer model of the present invention.

[0065] Part number explanation:

[0066] 1-Electrode assembly; 2-Furnace cover; 3-Upper furnace body; 3a-Preheating chamber; 4-Hot air ring pipe; 5-Hot air inlet; 6-Molten metal outlet; 7-Lower furnace body; 8-Slag outlet; 9-Feeding device; 10-Dust removal pipe; 11-Baffle mechanism; 11a-Main support beam; 11b-Baffle arm; 12-Material; 13-Slag liquid; 14-Molten metal; 15-Hot air generator; 16-Nozzle; 17-Stacking space; 17a-Lower space; 17b-Upper space; 18-Maintenance partition; 19-First drive mechanism; 19a-Drive component; 19b-Support frame; 20-Second drive mechanism; 21-Weighing device; 22-Flue gas circulation bypass; 23-Burn. Detailed Implementation

[0067] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0068] Example

[0069] Research has shown that in addition to adopting a series of technical measures (such as scrap preheating and electric furnace design optimization), reducing electric furnace power consumption can also be achieved by implementing energy grading in electric furnace smelting to improve energy utilization efficiency.

[0070] Using cold scrap steel / reduced iron as raw material as an example:

[0071] Scrap steel / reduced iron raw material 40℃

[0072] Tapping temperature of molten steel: 1460~1640℃

[0073] The flame temperature of a natural gas burner is 2000℃ (even higher temperatures can be achieved with pure oxygen / oxygen-enriched gas).

[0074] Arc temperature 4000~8000℃

[0075] The data above shows that, due to the temperature difference between the heat source and the heated medium, the theoretical efficiency of chemical burners heating cold scrap steel / reduced iron is relatively high (over 50-80%); however, the theoretical efficiency of chemical burners heating the surface heat of molten steel is very low (less than 20%, as it is carried away and discharged by the hot flue gas). The surface heat conduction model of traditional electric furnace burners (pure oxygen or oxygen-enriched combustion) is as follows: Figure 13 As shown, the theoretical thermal efficiency of electric arc heating is very high for both scrap steel and molten steel (covered with foam slag), but it is limited by the low energy conversion efficiency of electricity production.

[0076] The concept of energy tiered transfer in electric arc furnace production is to use chemical energy to preheat scrap steel / reduced iron raw materials in a lower temperature range (100-1200℃, depending on the equipment structure) to avoid the problem of low power generation energy efficiency (40%), while using electric energy for heating and smelting in a higher temperature range (800-1640℃).

[0077] For chemical energy heat transfer modes, the heat transfer efficiency of different designs can vary greatly. According to the following theoretically achievable blower heat transfer model, the heat transfer efficiency of hot air gas-solid contact, which does not consider the heat dissipation of the device, can reach (1200-300) / 1200*100%=75% (related to material temperature, hot air / flue gas temperature, material heating time, size of the stacking space, height of the stacking space, heat loss in the preheating chamber, etc.), which is much higher than the total efficiency of electric heating 21%, and also higher than the heat conduction efficiency of the burner surface of traditional electric furnace (after the electric furnace forms a flat melting pool, the heat efficiency is less than 20%).

[0078] The high-temperature hot air forced draft mode does not require a very high temperature for the hot air (compared to the burner of a traditional electric furnace: natural gas + pure oxygen), which provides a wide range of choices for fuel and heat source. The hot air heat transfer model of this invention is as follows: Figure 14 As shown.

[0079] Therefore, combining blast heating with an electric furnace is an important technical approach to improve the overall thermal efficiency of the electric furnace. This requires providing sufficient material storage space and height, and establishing a counter-current heat transfer mechanism between the material and the hot airflow. Based on this, the present invention provides a controllable flow chamber blast electric furnace device and smelting method. It can be used to melt low-quality direct reduced iron, smelt mixed direct reduced iron / scrap steel (crushed material) feedstocks, or melt certain metal ores, etc.

[0080] like Figures 1 to 11 As shown in this example, a material flow controllable blast furnace device includes a lower furnace body 7, an upper furnace body 3, a preheating chamber 3a, a furnace cover 2, an electrode assembly 1, a material flow control device, etc.

[0081] The lower furnace body 7 has a melting pool for separating the molten material 12 and the slag liquid 13. The lower furnace body 7 is provided with a slag outlet 8 and a molten metal outlet 6, wherein the height of the slag outlet 8 is higher than the height of the molten metal outlet 6. The material 12 can be direct reduced iron (e.g., sponge iron produced by a vertical furnace), or the material 12 includes direct reduced iron and scrap steel, or the material 12 is an alloy ore.

[0082] The upper furnace body 3 is installed on the lower furnace body 7 and located above the lower furnace body 7. The upper furnace body 3 has at least one preheating chamber 3a, which can be installed vertically or at an incline. The upper furnace body 3 is provided with a material stacking space 17 extending longitudinally from the preheating chamber 3a to the melting pool. That is, the material stacking space 17 includes the part inside the preheating chamber 3a and the part below the preheating chamber 3a to the melting pool. The material stacking space 17 has a certain longitudinal height, and the lower end of the material stacking space 17 is connected to the melting pool. The material stacking space 17 is used to stack material 12. The material 12 can fall from the material stacking space 17 to the melting pool.

[0083] The material flow control device includes a material blocking mechanism 11 and a drive mechanism for driving the material blocking mechanism 11 to discharge material. The material blocking mechanism 11 is located in the lower part of the preheating chamber 3a. The material blocking mechanism 11 divides the material storage space 17 into a lower space 17a and an upper space 17b, namely, the upper space 17b located above the material blocking mechanism 11 and the lower space 17a located below the material blocking mechanism 11. The material blocking mechanism 11 has a permeable gap, allowing flue gas and hot air to rise and pass through the material blocking mechanism 11 to preheat the material in the upper space 17b. The material in the upper space 17b is piled up from the material blocking mechanism 11, while the material in the lower space 17a is piled up from the layer of molten metal or slag. There is usually a gap between the top of the material piled in the lower space 17a and the material blocking mechanism 11.

[0084] When material 12 is added into the preheating chamber 3a, material 12 can fall under its own gravity and accumulate from bottom to top in the melting pool below the stacking space 17 and within the stacking space 17; the baffle mechanism 11 divides the stacked material 12 into lower material and upper material. During the first addition, the baffle mechanism 11 can be in the discharging state, and the material falls downward into the melting pool and the lower space. After the material below the baffle mechanism 11 has accumulated to the required level, the stacking continues, and the material accumulates on the baffle mechanism 11.

[0085] The furnace cover 2 is installed on the lower furnace body 7; or it is installed on the upper furnace body 3 and located between the preheating chambers 3a. The furnace cover 2, the upper furnace body 3, and the lower furnace body 7 together form a smelting preheating space; the furnace cover 2 is provided with electrode holes, and the electrode assembly 1 extends into the melting pool of the lower furnace body 7 after passing through the electrode holes of the furnace cover 2; there is an insulating seal between the electrode assembly 1 and the electrode holes.

[0086] The lower part of the upper furnace body 3 (the lower part of the preheating chamber 3a or the upper furnace body 3 below the preheating chamber 3a) is provided with a hot air inlet 5. High-temperature hot air can be introduced into the lower part of the preheating chamber 3a through the hot air inlet 5 to preheat the material 12 piled in the stacking space 17. This includes heating the material 12 directly sprayed by the hot air, as well as heating the material in the space above the hot air inlet 5 during the upward diffusion of the hot air.

[0087] An air outlet 10 is provided at the upper part of the preheating chamber 3a for discharging smelting flue gas in the smelting preheating space. The material stacking space 17 also serves as an upward discharge channel for the smelting flue gas and hot air generated during the melting of the electrode assembly 1. The upper end of the discharge channel is connected to the air outlet 10. During the upward process of the smelting flue gas and hot air, they also exchange heat with the material 12. In the mode of heat exchange with the material 12, the lower material above the molten pool mainly undergoes surface heat exchange, while the upper material above the baffle mechanism 11 undergoes flue gas / hot air diffusion heat exchange. The heat exchange surface area is large and the thermal efficiency is high.

[0088] Each of the preheating chambers 3a is equipped with a feeding device 9 on its top, and an air outlet 10 is located on the side or top of the upper part of the preheating chamber 3a, and the air outlet 10 is higher than the top of the material storage space 17. The feeding device 9 may also be installed on the furnace cover 2 as needed.

[0089] During the electric arc melting process, the material 12 in the melting pool gradually melts, and the material 12 in the stacking space 17 gradually falls. In specific operation, the lower material can be completely melted, while the upper material can be supported by the baffle mechanism 11. The movement of the baffle mechanism 11 and the feeding operation of the feeding device 9 are controlled as needed to achieve the control of the lower and upper materials.

[0090] Since the material storage space 17 also serves as a flue gas discharge channel, the smelting flue gas and hot air exchange heat with the material during the upward discharge process. The reverse motion of the material and hot air flow promotes heat transfer and improves heat utilization efficiency.

[0091] During the material smelting process, some of the hot air chemical energy is used to replace electrical energy, reducing electricity consumption and thus achieving emission reduction and improved economic efficiency. The baffle mechanism 11 supports and preheats the material in the upper space 17b, and reduces the amount of raw materials or metal elements carried away by the slag during slag discharge, thereby increasing metal yield, improving economic efficiency, reducing emissions, and facilitating the clearing of the lower space and slag. The baffle mechanism 11 can control the amount of material in the upper and lower spaces 17b as needed.

[0092] like Figure 1 , Figure 2 , Figure 4 , Figure 5 As shown in some embodiments, the furnace cover 2 and the electrode assembly 1 are located on one side of the preheating chamber 3a, that is, the furnace cover 2 and the upper furnace body 3 are arranged side by side and are both installed on the lower furnace body 7.

[0093] like Figures 6 to 11 As shown, in some embodiments, there are two or more preheating chambers 3a, each preheating chamber 3a having at least one set of material flow control devices, with the furnace cover 2 and electrode assembly 1 located between the preheating chambers 3a. In this structure, the furnace cover 2 is essentially supported on the upper furnace body 3.

[0094] In some embodiments, the hot air inlet 5 is located above the baffle mechanism 11 (not shown), and the incoming hot air can preheat the material in the upper space 17b. This structure can reduce the impact of hot air on the lifespan of the baffle mechanism 11.

[0095] like Figure 1 , Figure 4 , Figure 6 As shown, in some embodiments, the hot air inlet 5 is located below the baffle mechanism 11, on the upper furnace body 3 below the preheating chamber 3a (or at the lower part of the preheating chamber 3a), and the hot air supplied can preheat the materials in the lower space 17a and the upper space 17b, thereby increasing the range of preheated materials.

[0096] like Figure 8 As shown, in some embodiments, the lower furnace body 7 is circular, and two or more preheating chambers 3a are arranged at intervals along the circumference of the lower furnace body 7. The upper space 17b of each preheating chamber 3a is separated from each other, and the lower space 17a of each preheating chamber 3a is connected through the space above the molten pool.

[0097] like Figure 9 and Figure 11 As shown, in some embodiments, the lower furnace body 7 is elongated, and multiple preheating chambers 3a are arranged at intervals along the length of the lower furnace body 7. Two sets of preheating chambers 3a can be arranged opposite each other in the width direction of the lower furnace body 7, and the electrode assembly 1 is located between the opposite preheating chambers 3a.

[0098] like Figure 2 , Figure 5 , Figure 9 , Figure 11 As shown, in some embodiments, the cross-sectional shape of the material storage space 17 of the preheating chamber 3a is generally a rectangle with rounded corners to facilitate the design of the material blocking mechanism 11, or it can be a polygon or other shapes.

[0099] like Figure 3As shown, in one embodiment of the present invention, the material blocking mechanism 11 has a comb-like structure, including a main support beam 11a and multiple material blocking arms 11b connected to the main support beam 11a. The material blocking arms 11b are arranged parallel to each other and spaced apart. One end of each material blocking arm 11b is connected to the main support beam 11a, and the other end is a free end. The gaps between the material blocking arms 11b form ventilation gaps. The material blocking arms 11b extend into the material storage space to block the material. The ventilation gaps are also gaps for material to fall. The double arrows indicate the vibration direction of the material blocking mechanism 11. The material falls downwards, while hot air and flue gas rise through the ventilation gaps.

[0100] The gap allows upward-diffusing flue gas and hot air to pass through, while the baffle arm 11b blocks the falling material. Considering the bridging and accumulation effect caused by material friction, the gap design is generally 3 to 10 times the size of the material particles. To improve the baffle characteristics and air permeability, similar mixtures with larger dimensions can also be mixed into the material. For example, in the case of direct iron ore raw materials, hot-pressed briquettes or scrap steel crushed materials or block coke with controllable dimensions can be mixed in to increase the material gap and improve air permeability.

[0101] The driving mechanism includes a first driving mechanism 19, which can drive the material blocking mechanism 11 to extend into or out of the material storage space 17 at least partially along the side of the preheating chamber 3a to control the material flow; the movement trajectory of the material blocking mechanism 11 can be a straight line or an arc.

[0102] The depth to which the baffle mechanism 11 extends into the preheating chamber determines the opening size of the connecting channel between the lower space 17a and the upper space 17b, allowing for complete isolation or full opening, thereby achieving material flow control and regulating the stockpile size of materials in the lower and upper parts of the smelting process. This method is suitable for common materials found in steel plants, such as blocky and flaky scrap steel, granular direct reduced iron, granular / small block alloy materials, granular / small block ores, and sized scrap steel crushed materials and their mixtures. This method offers very high reliability for clearing the upper space 17b. For example, clearing can be achieved when the baffle arm 11a is completely withdrawn from the preheating chamber 3a.

[0103] This example uses a comb-shaped material-stopping mechanism 11 as an example. Figure 1 and Figure 3As shown, the stop arm 11b is arc-shaped. The first drive mechanism 19 includes a drive component 19a and a support frame 19b. One end of the drive component 19a is hinged to the outer wall of the preheating chamber 3a, and the other end is hinged to the support frame 19b to drive the support frame 19b to pitch. The stop mechanism 11 is mounted on the support frame 19b. In this example, there are two support frames 19b. The upper end of the support frame 19b is hinged to the outer wall of the preheating chamber 3a (for example, connected to the outer wall of the preheating chamber 3a through a hinged support). The two ends of the main support beam 11a are connected to the lower part of the two support frames 19b to improve the support stability of the stop mechanism 11 during movement. The upper end of the support frame 19b is hinged to the outer wall of the preheating chamber 3a or other structure, and pitches and swings around the hinge point. The stop arm 11b is an arc-shaped structure with the hinge point as the center. The drive component 19a can be a hydraulic cylinder, a pneumatic cylinder, or other structures that can drive the support frame 19b to swing.

[0104] The drive components 19a can also be designed as a group placed in the middle, supported by a connecting arm in the middle of the main support beam 11a. Figure 10 (Example).

[0105] like Figure 1 and Figure 3 As shown, in some embodiments, the material-discharging mechanism 11 discharges material via vibration. The driving mechanism includes a second driving mechanism 20 for driving the material-discharging mechanism 11 to vibrate. The second driving mechanism 20 drives the material-discharging mechanism 11 to vibrate, causing the material to fall through the gap between the material-discharging arms 11b. The material flow can be changed by controlling the vibration amplitude. The vibration direction can be transverse or longitudinal. The transverse direction includes a direction parallel to the main support beam 11a and a direction perpendicular to the material-discharging arms 11b, while the longitudinal direction can be up and down. The number of second driving mechanisms 20 can be one or two sets, placed in a suitable location and with a suitable vibration direction selected.

[0106] The material-blocking mechanism 11 is driven by the second drive mechanism 20 to vibrate, achieving feeding by bridging and accumulating the broken material in the gaps. This allows all / part of the stockpile 17b to controllably fall through the gaps in the material-blocking mechanism 11 into the lower space 17a and the lower furnace body 7, with material flow control achieved through vibration. This feeding method is suitable for: granular direct reduced iron, granular / small block alloy materials, granular / small block ores, and sized scrap steel crushed materials and their mixtures. The second drive mechanism 20 can be any physically feasible vibration device, including mechanical eccentric block vibrators, compressed air vibrators, magnetic vibrators, etc. Generally speaking... Figure 3The three-dimensional vibration force direction of the second drive mechanism 20 shown can break the material bridging above the baffle mechanism, allowing granular material to fall into the lower furnace body 7 from the gaps in the baffle mechanism or the gap between the end of the baffle mechanism 11 and the side wall of the preheating chamber 3a. The direction of the force of the vibration device should be selected to ensure that the baffle mechanism has a good effect on breaking the material bridging, so as to ensure good downward flow of the material. The vibration device can be set on the main support beam 11a or at the end of the main support beam 11a, etc. Generally, the vibration of the vibration device drives the entire baffle mechanism 11 to vibrate.

[0107] In actual operation, the material flow can be controlled by extending the baffle mechanism 11 into / out of the preheating chamber, or by driving the baffle mechanism to vibrate. Alternatively, depending on the material condition, the baffle mechanism can be extended into / out of the preheating chamber and used alternately (or simultaneously) with vibration to achieve material flow control.

[0108] A weighing device 21 can be installed on the material flow control device to assess the amount of material fed based on the insertion depth of the baffle mechanism 11. A typical weighing device 21 can be a strain gauge 21 and its detection equipment installed on the support frame 19a, with an elastic member on the support frame 19a that cooperates with the strain gauge, and the weight is determined by detecting the change in the strain gauge; or a standard material weight detection element can be installed on a hinged support (not shown) at the upper end of the support frame 19b.

[0109] In one embodiment of the present invention, the furnace cover 2 or the upper furnace body 3 is provided with a nozzle 16 for spraying carbon powder onto the preheated material.

[0110] In some embodiments, to improve heating efficiency and heating uniformity, a plurality of hot air inlets 5 are arranged circumferentially at intervals on the lower part of the upper furnace body 3. A hot air ring pipe 4 surrounds the outer side of the lower part of the upper furnace body 3, and each hot air inlet 5 is connected to the hot air ring pipe 4. The air inlet of the hot air ring pipe 4 is connected to a hot air generating device 15. The hot air generating device 15 can be a combustion device, such as a hot blast stove, which uses chemical fuels such as natural gas, coal (pulverized), and heavy oil to generate high-temperature flue gas, or even under oxygen-rich / pure oxygen conditions. If a reducing atmosphere of flue gas is required, carbon, coal, or fuel gas can be added to the hot air to achieve reducing regulation of the flue gas through fuel-rich combustion.

[0111] The hot air source can also be a mixture of high-temperature flue gas generated by the hot air generator 15 and some high-temperature flue gas discharged from the electric furnace itself, to regulate the hot air temperature appropriately, reduce the mixing of cold air, and improve thermal efficiency, such as... Figure 11 As shown.

[0112] During the smelting process, burners / nozzles can be used to replenish the temperature of the cold zone inside the furnace or to spray and adjust the atmosphere inside the furnace. The resulting flue gas, the blown-in hot air, and the smelting flue gas from the electrode assembly 1 rise upwards, together preheating the stack space 17 and the descending material 12. The flue gas and hot air diffuse upwards, passing through the gaps between the materials 12, and form contact heat conduction heating with the materials in the stack space and the descending material 12. The flue gas and hot air after heat exchange are discharged from the air outlet 10 for dust removal or recycling, etc.

[0113] like Figure 12 As shown, in some embodiments, a burner 23 is arranged inside the hot air inlet 5 or the hot air inlet 5 is replaced with a burner 23 (when the reducing atmosphere requirement in the furnace is not high). The material 12 is heated by burning through the burner 23, and the flue gas discharged from the air outlet can also be partially recycled.

[0114] In other embodiments, the lower part of the upper furnace body 3 is provided with both hot air inlet 5 and burner. Multiple burners are arranged circumferentially along the preheating chamber 3a, which means that the method of blowing in hot air and burning the burner for heating can be combined.

[0115] Specifically, the burner and the hot air inlet 5 are located at the same height or at different heights. When the burner and the hot air inlet 5 are located at the same height, the burner and the hot air inlet 5 can be arranged alternately along the circumference of the preheating chamber 3a, or they can be arranged according to requirements.

[0116] The hot air blown from the hot air outlet allows for temperature and flue gas composition control, thus meeting the needs of the process environment. For example, controlling the reducing atmosphere of the hot air (oxygen-free or low-oxygen) can reduce iron loss when the material is reduced iron, improving yield and economic efficiency, and preventing equipment from being oxidized at high temperatures. Furthermore, controlling the hot air temperature prevents the reduced iron from caking in the shaft, ensuring the equipment operates at a suitable temperature, making the equipment more stable, reliable, and requiring less maintenance.

[0117] In some embodiments, a feeding device 9 is provided on the top of the preheating chamber 3a, and the air outlet 10 is located on the side or top of the upper part of the preheating chamber 3a, and the air outlet 10 is higher than the top of the stacking space 17. The top feeding and side air outlet method is adopted, which is convenient for layout. The air outlet 10 is higher than the top of the stacking space 17, so that all materials 12 can be heat exchanged and the materials 12 are prevented from escaping from the air outlet 10.

[0118] The air outlet 10 can be connected to a dust collection device for subsequent dust removal. Alternatively, the air outlet 10 can also be connected to a flue gas recovery and reuse circulation pipeline. In this example, the electric furnace unit also includes a circulation bypass 22 to recover and reuse a portion of the flue gas. Figure 11 ).

[0119] This invention proposes a smelting method using a controllable material flow caving electric furnace.

[0120] The lower furnace body maintains a portion of the molten pool;

[0121] Material 12 is added to the preheating chamber 3a through the feeding device 9. Since the material blocking mechanism 11 divides the stacking space 17 into an upper space 17b and a lower space 17a, the material blocking mechanism 11 is in the closed state. Material 12 accumulates upward from the material blocking mechanism 11 into the upper space 17b of the preheating chamber 3a. Some material may fall into the melting pool or the lower space 17a through the gap of the material blocking mechanism 11. During the first feeding, the material blocking mechanism 11 can also be partially or completely opened to allow some material to fall into the melting pool and the lower space first, and then the material blocking mechanism 11 can be closed to control the discharge.

[0122] High-temperature hot air is blown into the material storage space 17 through the hot air vent 4. When the hot air vent 4 is above the material blocking mechanism 11, it can preheat the material in the upper space 17b. When the hot air vent 4 is below the material blocking mechanism 11, it can preheat the material in the lower space 17a and the upper space 17b.

[0123] In the lower furnace body, the electric arc of the electrode assembly 1 and the hot air together heat and melt the material 12 below the baffle mechanism 11. The molten metal formed after the material 12 melts sinks to the bottom of the lower furnace body, and the slag layer floats on the molten metal.

[0124] According to smelting requirements, the baffle mechanism 11 is driven to continuously or intermittently discharge material, so that the material can be controlled to descend and fall into the lower space 17a of the preheating chamber 3a and the lower furnace body 7; for example, when the material below the baffle mechanism 11 melts to a specified degree (based on the operator's experience and testing during manual production or the parameters set by the process model during automatic smelting); during or after the material is discharged, the feeding device 9 can also replenish the material to the upper space of the preheating chamber 3a; real-time online material discharge and replenishment can be realized.

[0125] The flue gas generated during the electric arc smelting process of electrode assembly 1 and the hot air delivered by hot air outlet 4 diffuse upward through the gap between materials to preheat the materials in the stacking space 17, and are discharged from air outlet 10 after heat exchange.

[0126] When the liquid level reaches the set position, the slag liquid is discharged from the slag outlet 6, and the molten metal is discharged from the molten metal outlet 8 of the lower furnace body.

[0127] In one embodiment of the present invention, the material discharge method can be to control the insertion degree (insertion amount) of the material blocking mechanism 11 into / out of the preheating chamber 3a, partially inserting / exiting into the preheating chamber 3a, or completely inserting / exiting into the preheating chamber 3a; or to discharge the material by vibration of the material blocking mechanism 11, with the material falling through the gap of the material blocking mechanism 11 and the gap between the material blocking mechanism 11 and the side wall of the preheating chamber 3a; or a combination of the two methods, with the two methods alternating or occurring simultaneously.

[0128] The present invention proposes another smelting method using the aforementioned controllable cavitary blast furnace device: when there are two or more preheating chambers 3a, each preheating chamber 3a is fed alternately to the furnace body 7 according to the smelting process requirements, and the material flow of each preheating chamber 3a is controlled by the baffle mechanism 11 during the feeding process.

[0129] Specifically, the smelting method of the above-mentioned device involves: using a charging point on the furnace cover, electric arc melting, or other methods such as liquid addition, to form a molten pool in the lower furnace body 7. The following mainly describes the smelting method during the preheating process of material 12.

[0130] The smelting operation method for preheating material 12 involves adding material 12 into preheating chamber 3a. Material 12 falls through the stacking space 17 and is blocked by the baffle mechanism 11 until it continues to accumulate in the upper space 17b to a height close to the height of the upper material (or the weight set by the weighing device 11b). The baffle mechanism 11 is fully or partially opened, or the baffle mechanism 11 vibrates, and all or part of the upper material falls from above the baffle mechanism 11 into the melting pool, forming the lower stack. The baffle mechanism 11 is then completely closed, and the feeding device 9 continues to add material until it is close to the upper material. During this period, high-temperature hot air and high-temperature flue gas from electrode smelting are injected into the hot air outlet 5 to heat the material 12 accumulated in the stacking space. The lower stack mainly undergoes surface heat conduction, and the hot air and flue gas that penetrate the baffle mechanism 11 diffuse and penetrate the heat exchange of the stack above the baffle mechanism 11.

[0131] As electrode assembly 1 is smelted by electric arc in the melting pool, the material accumulated below gradually melts, and the lower material in the lower space 17a falls naturally, gradually melting and decreasing in height. During this process, after the lower material has completely melted and maintained at the temperature for a period of time, slag and liquid are separated before slag removal and steel tapping are performed.

[0132] In this embodiment, during the smelting process of material 12, some of the electrical energy is replaced by hot air chemical energy, reducing electricity consumption and thus achieving emission reduction and improved economic efficiency. The temperature of the hot air is above 700°C, typically between 1000°C and 1500°C.

[0133] like Figure 1 and Figure 5 As shown, in some embodiments, the electric furnace is powered by either AC or DC power and employs a single preheating chamber 3a. This furnace type, considering the load-bearing capacity of important components such as the baffle mechanism 11, the working environment, and the ease of maintenance during equipment use, is well-suited for small-scale blast furnaces.

[0134] like Figures 6 to 11 As shown, in order to solve the problem of large-scale design, a technical solution with multiple preheating chambers 3a is adopted.

[0135] Figure 6 , Figure 7 Examples of front and top views of two preheating chambers 3a are provided. The electric furnace can be powered by either AC or DC power. The operation method and process are the same as for a single preheating chamber 3a, but the two preheating chambers 3a can be fed simultaneously or alternately by controlling their respective baffle mechanisms 11.

[0136] Figure 8 Examples of top views of 3 and 4 preheating chambers 3a in different lower furnace bodies 7 demonstrate one arrangement of 3 and 4 preheating chambers.

[0137] Figure 9 and refer to Figure 6 , Figure 10 The main view is a top view of the arrangement of 6 preheating chambers. The electric furnace is powered by AC or DC. Multiple slag discharge holes 6 and steel tapping ports 8 are opened on the side wall of the lower furnace body 7, and multiple electrode assemblies 1 are provided, which can realize the large-scale design of the blast furnace.

[0138] A temporary maintenance partition 18 is installed below the material blocking mechanism 11 to temporarily close the opening of the preheating chamber 7 on the lower furnace body 7 during the maintenance of the preheating chamber 3a.

[0139] Figure 11 The top view shows the arrangement of n preheating chambers 3a and m electrode assemblies 1 in series. Figure 10 The main view shows that the electric furnace is powered by AC or DC. Multiple slag outlets 6 and molten metal outlets 8 are opened on the side wall of the lower furnace body 7, which enables the ultra-large-scale design of the blast furnace.

[0140] The main advantages of using an electric furnace with multiple (two or more) preheating chambers 3a are:

[0141] Based on the realization of the single preheating chamber 3a electric furnace process, the large-scale and ultra-large-scale electric furnaces have become possible.

[0142] The electric furnace with multiple preheating chambers 3a has controllable charging points and charging amounts, enabling control over the charging in the melting pool of the lower furnace body 7, and controllable charging amount each time, thus greatly optimizing the electric furnace smelting process.

[0143] The material distribution points and amount in the multi-preheating chamber mechanism are controllable to a certain extent; the multi-preheating chamber stores more material, and the alternating feeding and preheating make the preheating time of the material in the preheating chamber longer, the material preheating more fully, and the heat transfer efficiency higher.

[0144] Electric furnaces with multi-preheating chamber structures also have strong fault tolerance characteristics. If a preheating chamber malfunctions, the hot air vent at the bottom of that preheating chamber can be shut down, and the external repairable parts can be maintained online.

[0145] Electric furnaces with multi-preheating chamber structures also have modular design features, which reduce the size, volume, and weight of individual preheating chambers and baffle structure components, facilitate the maintenance of the overall equipment, and improve the resistance of each part to mechanical and thermal load shocks, thereby improving the reliability of the components.

[0146] For this electric furnace, the oxidation-reduction characteristics of the hot air need to be adjusted according to different raw material properties. For example, if material 12 is mainly porous and flammable direct reduced iron, which is sensitive to the oxygen content in the flue gas, then a reducing gas (low oxygen content, containing reducing components such as CO, C, and H2) can be selected for the hot air blast. Coke or coal, or other solid fuels, can be mixed or layered as needed during batching. For other metal ores and scrap steel that are not sensitive to oxygen, direct heating with natural gas can be used. Generally, mixing coke, coal, or other solid combustibles into the batching of material 12 can increase the proportion of chemical energy in the electric furnace and improve its reducing properties.

[0147] Anyone skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this invention should still be covered by the claims of this invention.

Claims

1. A controllable material flow diaphragm-type electric furnace device, characterized in that, include: The lower furnace body has a melting pool; An upper furnace body is installed on a lower furnace body. The upper furnace body includes at least one preheating chamber and is provided with a material stacking space that extends longitudinally from the preheating chamber to the melting pool. Material can flow from the material stacking space to the melting pool. The furnace cover is installed on the lower or upper furnace body and together with the upper and lower furnace bodies, it forms a smelting preheating space. The electrode assembly extends into the lower furnace body after passing through the furnace cover; The material flow control device includes a material blocking mechanism and a drive mechanism for driving the material blocking mechanism to release material. The material blocking mechanism is located in the lower part of the preheating chamber and divides the material stacking space into upper and lower parts. The space above the material blocking mechanism is the upper space, and the space from the material blocking mechanism to the melting pool is the lower space. The material blocking mechanism has a venting gap. The material blocking mechanism has a comb-tooth structure, including a main support beam and multiple parallel and spaced material blocking arms connected to the main support beam. The gap between the material blocking arms forms the air-permeable gap, and the material blocking arms extend into the material stacking space to block the material. The driving mechanism includes a first driving mechanism and a second driving mechanism. The material blocking mechanism can be driven by the first driving mechanism to extend into or out of the material stacking space at least partially to control the material flow. The second driving mechanism is used to drive the material blocking mechanism to vibrate, thereby controlling the material flow. A hot air inlet is located at the lower part of the upper furnace body and is used to send hot air into the stacking space; The air outlet is located at the top of the preheating chamber; The material stacking space also serves as an exhaust channel for the electric arc melting fumes and hot air to diffuse upwards to the air outlet, and the fumes and / or hot air can rise from the lower space, pass through the baffle mechanism, and enter the upper space.

2. The controllable material flow caving electric furnace device according to claim 1, characterized in that: The number of preheating chambers is one, or the number of preheating chambers is two or more; each preheating chamber has at least one set of material flow control devices.

3. The controllable material flow caving electric furnace device according to claim 1, characterized in that: The lower furnace body is circular, and two or more preheating chambers are arranged at intervals along the circumference of the lower furnace body.

4. The controllable material flow caving electric furnace device according to claim 1, characterized in that: The lower furnace body is elongated, and multiple preheating chambers are arranged along the length of the lower furnace body.

5. The controllable material flow caving electric furnace device according to claim 1, characterized in that: The furnace cover and electrode assembly are located on one side of the preheating chamber; or there are two or more preheating chambers, and the furnace cover and electrode assembly are located between the preheating chambers.

6. The controllable material flow diaphragm-type electric furnace device according to claim 1, characterized in that: The preheating chamber or material storage space has a rectangular cross-section.

7. The controllable material flow caving electric furnace device according to claim 1, characterized in that: The vibration direction of the material blocking mechanism is either transverse or longitudinal.

8. The controllable material flow caving electric furnace device according to claim 1, characterized in that: The first driving mechanism includes a driving component and a support frame. The material blocking mechanism is mounted on the support frame. The driving component is used to drive the support frame to move linearly or swing around a hinge point.

9. The material flow controllable caving blast furnace device according to any one of claims 1-8, characterized in that: The material flow control device is equipped with a weighing device.

10. The material flow controllable caving electric furnace device according to any one of claims 1-8, characterized in that: The hot air vent is located above or below the material blocking mechanism.

11. The material flow controllable caving electric furnace device according to any one of claims 1-8, characterized in that: The controllable material flow diaphragm blast furnace device also includes a hot air generating device and a hot air ring pipe. The upper furnace body is arranged with multiple hot air inlets at intervals along the circumference. Each hot air inlet is connected to the hot air ring pipe, and the hot air ring pipe is connected to the hot air generating device.

12. The material flow controllable caving blast furnace device according to any one of claims 1-8, characterized in that: The lower part of the upper furnace body is provided with multiple burners arranged circumferentially for blowing air into the furnace; or the hot air inlets can be replaced with burners.

13. The controllable material flow caving electric furnace device according to claim 1, characterized in that: Each of the preheating chambers is equipped with a feeding device on its top, and the air outlet is located on the side or top of the upper part of the preheating chamber, and the air outlet is higher than the top of the material storage space.

14. The controllable material flow caving electric furnace device according to claim 1, characterized in that: The furnace cover or upper furnace body is equipped with nozzles for spraying carbon powder onto the preheated material.

15. The controllable material flow caving electric furnace device according to claim 1, characterized in that: The preheating chamber is provided with a partition that can be extended into and pulled out below the material blocking mechanism.

16. A smelting method, employing the controllable material flow blast furnace device according to any one of claims 1-15, characterized in that: The lower furnace body maintains a portion of the molten pool; The material blocking mechanism separates the upper and lower spaces, allowing material to be added into the preheating chamber. The material then accumulates upwards in the upper space of the preheating chamber from the material blocking mechanism. High-temperature hot air is blown into the preheating chamber through the hot air vent to preheat at least the material above the baffle mechanism. In the lower furnace body, the electric arc and hot air work together to heat and melt the material below the baffle mechanism. The molten metal formed after the material melts sinks to the bottom of the lower furnace body, while the slag layer floats on top of the molten metal. Depending on the degree of smelting, the material feeding mechanism is driven to continuously or intermittently discharge material, causing the material to fall into the lower space and the lower furnace body; The flue gas and hot air diffuse upward through the gaps between the materials, preheating the materials in the stacking space, and are discharged from the air outlet after heat exchange. When the liquid level reaches the set position, the slag liquid is discharged from the slag outlet, and the molten metal is discharged from the molten metal outlet of the lower furnace body.

17. The smelting method according to claim 16, characterized in that: Material flow rate is controlled by controlling the movement of the material blocking mechanism as it extends into or out of the preheating chamber. Alternatively, the material can be discharged by driving the material-blocking mechanism to vibrate, and the material falls through the air gap of the material-blocking mechanism; Alternatively, material flow can be controlled by combining the insertion or withdrawal of the material stop mechanism into or out of the preheating chamber with the vibration of the material stop mechanism.

18. A smelting method, employing the controllable material flow blast furnace device according to any one of claims 1-15, characterized in that: There are two or more preheating chambers, and each preheating chamber is fed alternately to the furnace body at fixed points. During the feeding process, the material flow is controlled by a material blocking mechanism.

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