Downflow flash furnace and smelting method

Abstract

The application discloses a down-flow flash furnace and a smelting method, and belongs to the technical field of steel smelting. The main furnace reaction zone and the auxiliary furnace reaction zone are arranged above the molten pool area, and the lower end of the auxiliary furnace reaction zone is directly communicated with the lower end of the main furnace reaction zone. Based on the structure, the ore powder is pre-reduced by using the high-temperature tail gas discharged from the main furnace reaction zone in the auxiliary furnace reaction zone, and then is sent into the main furnace reaction zone to be finally reduced by the high-temperature reducing gas, so that the reduction efficiency and the heat utilization rate are obviously improved, and the compact design of the furnace body is realized.

Description

Technical Field

[0001] This invention belongs to the field of iron and steel smelting technology, specifically relating to a co-current flash furnace and a smelting method. Background Technology

[0002] Traditional blast furnace ironmaking relies on sintering and coking processes, which are characterized by long processes, heavy pollution, high energy consumption, large carbon emissions, and stringent requirements on the grade of coke and ore fed into the furnace. Among non-blast furnace ironmaking processes, hydrogen-based shaft furnaces have lower carbon emissions, but require the use of high-grade pellets (iron grade >66%), resulting in high raw material costs and limited supply. Fluidized bed processes can use ore powder directly, but the operating window is narrow, and adhesion and loss of flow are prone to occur, so the reliability for industrial application needs to be verified.

[0003] Flash ironmaking technology has become a research hotspot in recent years, allowing iron ore powder to be injected into a high-temperature furnace and complete the reduction reaction within seconds. Chinese patent document CN117904382A proposes a flash ironmaking method and system, in which iron ore powder is flash-reduced in a reduction tower to form sponge iron, which is then melted in a smelting pool and agitated with injected gas. This technology improves slag-iron separation through bottom gas injection, but it has the following shortcomings: First, no gas-solid separation device is installed between the reduction tower and the smelting pool, allowing fine ore particles to easily escape with the gas flow, resulting in insufficient residence time; second, the smelting pool structure is not optimized for viscous slag, and its adaptability to difficult-to-separate ores such as high-phosphate ore needs improvement; third, it mainly targets newly built facilities, with insufficient consideration for the retrofitting and utilization of existing blast furnaces.

[0004] Another Chinese patent document, CN113106182A, proposes a hydrogen-based flash ironmaking device based on a modified blast furnace. This patent transforms a traditional blast furnace into a flash furnace, using a hydrogen production device to generate hydrogen. Powdered iron ore, after drying and pre-reduction, is fed in through a top spray gun, moving in the opposite direction of the hydrogen and completing reduction within seconds. The ore then falls into a slag-iron separation pool. This technical solution has positive advantages such as the ability to modify and utilize existing blast furnaces and the use of hydrogen for low carbon emissions. However, it still has significant shortcomings in practical applications: First, the device consists of two independent towers—the flash furnace and the drying / pre-reduction tower—connected by an external pipe. This split design results in a large footprint and low system integration, making it unsuitable for blast furnace modification scenarios with limited space. Second, the pre-reduction flue is arranged downwards, with the airflow direction aligned with the downward direction of the ore powder. Large particles settle rapidly, while fine particles escape quickly with the airflow, resulting in insufficient residence time for each particle size, thus limiting reduction efficiency. Third, pre-reduction and final reduction are completed in separate devices, causing heat loss during intermediate transfer, which is detrimental to the cascade utilization of thermal energy. In addition, the process is overly dependent on hydrogen, and the control window for completing the reaction within seconds is stringent, posing challenges to process stability.

[0005] To address the problems in the existing technologies mentioned above, such as large footprint of split-type layout, insufficient residence time due to unreasonable airflow organization, heat loss caused by separation of pre-reduction and final reduction, insufficient adaptability of structural design to different particle size mineral powders, and difficulty in separating slag and iron for specific minerals, this invention proposes a novel flash blast furnace with a compact structure, suitable for blast furnace modification, high reduction efficiency, and good slag and iron separation effect. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a co-current flash furnace and a smelting method. By setting a main furnace reaction zone and an auxiliary furnace reaction zone above the molten pool zone, and directly connecting the lower end of the auxiliary furnace reaction zone to the lower end of the main furnace reaction zone, based on the above structure, the ore powder is first pre-reduced in the auxiliary furnace reaction zone using the high-temperature tail gas discharged from the main furnace reaction zone, and then sent to the main furnace reaction zone for final reduction with high-temperature reducing gas. This significantly improves the reduction efficiency and heat utilization rate, and achieves a compact furnace design.

[0007] The technical problem to be solved by the present invention is achieved by the following technical solution: a co-current flash furnace, comprising a furnace body, a ore feeding device, a reducing agent supply unit and an auxiliary furnace feeding nozzle; The furnace body includes a main furnace reaction zone, an auxiliary furnace reaction zone, and a molten pool zone. The molten pool zone is located at the lower part of the furnace body. The main furnace reaction zone and the auxiliary furnace reaction zone are respectively located above the molten pool zone. The lower end of the auxiliary furnace reaction zone is directly connected to the lower end of the main furnace reaction zone. The main furnace reaction zone is divided into a solid reduction zone, a soft melting reduction zone, and a liquid zone from top to bottom; The upper part of the main furnace reaction zone is equipped with a ore feeding device and a reducing agent supply unit; The auxiliary furnace reaction zone is provided with a gas-solid two-phase outlet at the top, and at least one auxiliary furnace feed nozzle is provided in the lower part of the auxiliary furnace reaction zone. The molten pool zone includes a slag layer and a molten iron layer; the sidewall of the molten pool zone is provided with a slag outlet and an iron outlet, and the molten pool zone is used to accommodate the slag and iron coming from the main furnace reaction zone and to perform slag and iron separation.

[0008] In this invention, the lower end of the auxiliary furnace reaction zone is directly connected to the lower end of the main furnace reaction zone. At least one auxiliary furnace feed nozzle is provided in the lower part of the auxiliary furnace reaction zone to inject ore powder into the zone. A gas-solid two-phase outlet is provided at the top of the auxiliary furnace reaction zone to discharge the pre-reduced flue gas. The auxiliary furnace reaction zone utilizes the high-temperature furnace gas discharged from the main furnace reaction zone to pre-reduce the ore. The pre-reduced ore is then discharged from the auxiliary furnace reaction zone with the gas flow.

[0009] By placing the auxiliary furnace feed nozzle in the lower part of the auxiliary furnace reaction zone, the high-temperature furnace gas rising from the main furnace reaction zone pre-reduces the ore, extending the effective residence time of the ore powder in the reduction zone. Compared with the existing technology where the airflow direction is the same as the falling direction of the ore powder, in this scheme, the ore powder enters from the lower part of the auxiliary furnace reaction zone, forming a reasonable flow match with the rising airflow in the main furnace reaction zone. This effectively extends the residence time of ore powder of various particle sizes in the pre-reduction zone, avoiding the problem of insufficient reduction caused by the accelerated settling of coarse particles and the rapid escape of fine particles with the airflow, and enhancing the gas-solid contact efficiency.

[0010] The auxiliary furnace reaction zone (pre-reduction zone) and the main furnace reaction zone (final reduction zone) are spatially connected, which also realizes the cascade utilization of thermal energy and improves the heat utilization efficiency of the flash process.

[0011] Meanwhile, the lower end of the auxiliary furnace reaction zone is directly connected to the lower end of the main furnace reaction zone, forming an integrated and compact layout that significantly reduces the equipment footprint and lowers equipment investment costs. This integrated structure is suitable for new projects and is also convenient for low-cost retrofitting of existing blast furnaces—for existing blast furnace workshops, the original furnace structure can be directly utilized, and flash ironmaking can be achieved by adding auxiliary furnaces or internal partitions, without the need for large-scale site expansion.

[0012] Preferably, a gas-solid separation efficiency-enhancing device is provided on the lower side wall of the main furnace reaction zone of the present invention; The gas-solid separation efficiency improvement device includes an annular baffle wall installed on the inner wall of the furnace body and a flow hole installed in the center of the annular baffle wall; Preferably, at the flow passage, the flow area of ​​the furnace cavity is reduced, and the area is 5% to 50% of the inner diameter area of ​​the main furnace reaction zone; Preferably, the gas-solid separation efficiency-enhancing device includes several layers of annular baffles spaced from top to bottom within the main furnace reaction zone. The flow holes form a throat structure, accelerating the airflow and carrying fine mineral powder downwards rapidly, giving the powder greater downward kinetic energy and making it easier for the powder to enter the molten pool, reducing the amount that escapes with the exhaust gas. Furthermore, it increases the probability of collision and fusion of the furnace charge particles, increasing the size of the furnace charge in the exhaust gas, making it impossible for the gas to carry the charge particles, thus achieving gas-solid separation.

[0013] A gas-solid separation efficiency-enhancing device is installed in the lower part of the main furnace reaction zone or near the connection point between the auxiliary furnace reaction zone and the main furnace reaction zone. The baffle wall surrounds the inner wall of the furnace body in the reduction melting zone. The inner side of the annular baffle wall forms a flow passage. The flow passage area of ​​the furnace cavity at the flow passage is reduced, and the area is 5% to 50% of the area of ​​the main furnace reaction zone. The annular baffle wall consists of several layers and is located above the flue gas discharge channel, i.e., above the connection point between the main furnace reaction zone and the auxiliary furnace reaction zone.

[0014] The flow passages can be circular, square, irregularly shaped, or composed of multiple passages, formed by the baffle structure. As the flue gas flows towards the low-pressure zone for discharge, it must pass through these flow passages. During this process, due to the reduced flow area, the downward velocity of the flue gas and its entrained material is accelerated compared to the upper furnace chamber of the gas-solid separation efficiency improvement device. If the material particles are still solid at this point, the higher velocity, due to inertia, helps maintain the particle velocity vector better after passing through; while the gas rapidly decelerates and diffuses after passing through, simultaneously changing its direction of motion towards the flue gas discharge channel. This significantly increases the gas-solid separation efficiency in the lower furnace chamber of the gas-solid separation efficiency improvement device after passing through, reducing the amount of material carried out by the airflow.

[0015] Preferably, in this invention, the part of the main furnace reaction zone near the entrance to the softening and reduction zone is provided with a sudden change in the inner diameter of the furnace shell; Preferably, the furnace body diameter decreases abruptly, or gradually decreases thereafter. The maximum flow area at the abrupt change in the furnace shell's inner diameter is 10% to 50% larger than the cross-section of the main furnace reaction zone above it, and the increased flow area extends into the liquid zone. This diameter-expanding structure prevents molten material from adhering to the furnace wall, which would reduce the furnace body's flow area. It also makes it easier for molten material to drip in the expanded diameter section, avoiding furnace nodules and ensuring stable furnace conditions.

[0016] Preferably, a heat replenishment unit is provided in the middle and / or lower part of the main furnace reaction zone of the present invention; Preferably, a carburizing agent spray gun is inserted into the slag layer of the molten pool zone; Preferably, the heating unit is a heating spray gun, a heating flue gas inlet, or a reducing gas inlet, and the heating spray gun is connected to a fuel supply device and a combustion-supporting gas supply device; Preferably, the fuel used in the fuel supply device is pulverized coal, natural gas, or coal gas, and the auxiliary combustion gas used in the combustion gas supply device is pure oxygen or oxygen-enriched air. By setting up a supplementary heating unit, the temperature field inside the furnace can be flexibly adjusted according to the characteristics of the raw materials and process requirements, adapting to the reduction requirements of different minerals and improving process adaptability.

[0017] Preferably, the reducing agent supply unit of the present invention comprises a reducing gas inlet and a hot reducing gas supply unit, wherein the reducing gas inlet is disposed on the side wall of the furnace body and is connected to the hot reducing gas supply unit; The thermal reducing gas supply unit is used to heat the reducing gas at room temperature; Preferably, the heat reduction gas supply unit includes at least one combustion chamber connected to the furnace body; The combustion chamber is provided with a combustion cavity, a combustion nozzle is provided at one end of the combustion chamber along the axial direction, and a reducing gas outlet is provided at the other end. The reducing gas outlet is connected to the reducing gas inlet on the side wall of the furnace body. The combustion nozzle is equipped with a fuel inlet and an auxiliary combustion gas inlet; at least one reducing gas injection inlet is provided at the combustion end or side wall of the combustion chamber; Preferably, the reducing gas introduced into the reducing gas injection inlet flows closely against the circumferential sidewall of the combustion chamber to form an air curtain; the fuel and combustion-supporting gas burn in the chamber of the original gas heater to generate heat, which is used to heat the reducing gas, and at the same time, the reducing gas forms an air curtain in the chamber of the original gas heater to protect the inner wall of the combustion chamber. Preferably, the reducing gas injection inlet forms an angle with the combustion chamber axis to form a spiral gas curtain. This heating method can effectively increase the reducing gas temperature and enhance the reduction reaction kinetics. After the reducing gas enters through the reducing gas injection inlet, it moves in a spiral shape close to the side wall of the combustion chamber, increasing the travel distance before entering the reducing gas inlet, which helps to increase the reducing gas temperature. When carburization of molten iron in the furnace is required, it is achieved by injecting the necessary excess pulverized coal. Preferably, the thermal reducing gas supply unit includes at least one plasma heating device connected to the reducing gas inlet. The plasma heating device can heat the reducing gas to a higher temperature, thereby further improving the reduction efficiency. Preferably, the fuel is pulverized coal, coal gas, or natural gas, and the combustion-supporting gas is pure oxygen or oxygen-enriched gas.

[0018] Alternatively, the reducing agent supply unit may be a composite spray gun of pulverized coal and oxygen, which generates reducing hot flue gas through incomplete combustion in the furnace.

[0019] Preferably, the thermal reducing gas supply unit is connected to the reducing gas supply device. Preferably, the reducing gas supply device is one or a combination of more than one of the following: a coal gasifier or coal-to-hydrogen unit, an electrolytic hydrogen unit, a coke oven gas-to-hydrogen unit, a methanol-to-hydrogen unit, and an ammonia-to-hydrogen unit. This diversified gas source design reduces dependence on a single gas source, allowing for the selection of the most economical and environmentally friendly reducing gas preparation method based on resource conditions.

[0020] Preferably, the auxiliary furnace feed nozzle is connected to the mineral powder drying unit. The mineral powder drying unit is connected to the crushing and grinding device to realize integrated processing from raw ore to qualified mineral powder, ensuring stable quality of the mineral powder entering the furnace. Preferably, the mineral powder drying unit is a rotary kiln, a bubbling fluidized bed, or a circulating fluidized bed; Preferably, the mineral powder drying unit is connected to the gas-solid two-phase outlet, and uses the waste heat of the system exhaust gas for drying, thereby realizing the recovery and utilization of the waste heat of the exhaust gas.

[0021] Preferably, in this invention, the gas-solid two-phase outlet is connected to the first dust collector; The discharge port of the first dust collector is connected to the hopper of the ore feeding device; Preferably, the air outlet of the first dust collector is connected to the hot-side inlet of the heat exchange device; The hot side outlet of the heat exchange device is connected to the inlet of the second dust collector. One outlet of the second dust collector is connected to the external supply network through a pressure regulating valve group, and the other outlet is connected to the carbon dioxide removal device and the dehydration device in sequence. The outlet of the dehydration device is connected to the inlet of the circulating fan, and the outlet of the circulating fan is connected to the cold side inlet of the heat exchange device. The cold side outlet of the heat exchange device is connected to the inlet of the hot reducing gas supply unit. Preferably, a sulfur dioxide removal device is provided between the hot-side outlet of the heat exchange device and the second dust collector; Preferably, a hydrogen conversion device is installed between the outlet of the second dust collector and the carbon dioxide removal device. The heat exchanger can recover and utilize the heat in the exhaust gas, while the external supply network and the hydrogen conversion device can recover and utilize the reducing gas in the exhaust gas. The hydrogen conversion device can convert CO into hydrogen, improving the reduction efficiency of the flash furnace. This system realizes waste heat recovery from flue gas, dust recovery, coal gas purification, and reducing gas recycling, significantly improving energy utilization efficiency and reducing emissions.

[0022] Preferably, in this invention, a tail gas reforming unit is provided on the side wall of the auxiliary furnace reaction zone near the connection with the main furnace reaction zone, for increasing the reducing gas content in the tail gas; Preferably, the tail gas reforming unit is a pulverized coal spray gun or a pulverized coal and steam combined spray gun. The tail gas exiting the main furnace reaction zone is reformed using the pulverized coal spray gun or the pulverized coal and steam combined spray gun to increase the proportion of reducing gases, i.e., to increase the reduction potential. Afterward, the tail gas passes through the auxiliary furnace reaction zone, specifically at the lower part of the auxiliary furnace reaction zone. Injecting pulverized coal can crack to produce H2 and CO, increasing the furnace gas reduction potential; injecting steam can react with CO in a water-gas shift reaction to generate more H2, while simultaneously regulating the furnace gas temperature and optimizing the pre-reduction conditions.

[0023] Preferably, in this invention, the furnace body includes a first furnace body and a partition wall; The first furnace body is vertically arranged, and the partition wall is located above the first furnace body, dividing the space above the first furnace body into the main furnace reaction zone and the auxiliary furnace reaction zone. The space below the first furnace body is the molten pool zone. Alternatively, the furnace body may include a second furnace body and a third furnace body; The lower end of the third furnace body is connected to the side wall of the second furnace body. The main furnace reaction zone and the molten pool zone are arranged from top to bottom in the second furnace body, and the auxiliary furnace reaction zone is located in the third furnace body. Preferably, the furnace body is a modified blast furnace; The structure above the hearth of the blast furnace body serves as the main furnace reaction zone, the hearth of the blast furnace serves as the molten pool zone, and the newly built furnace body connected to the lower part of the main furnace reaction zone serves as the auxiliary furnace reaction zone. Alternatively, a partition wall with cooling walls can be added inside the blast furnace to form a main furnace reaction zone and an auxiliary furnace reaction zone. This solution makes full use of existing blast furnace facilities, significantly reduces investment costs, and provides a transformation and upgrading path for eliminating outdated blast furnace capacity.

[0024] Preferably, in this invention, the molten pool region is provided with an extended section in the horizontal direction; The extended section is provided with a high-temperature gas inlet or a supplementary heating gas raw material supply device at the end away from the furnace body. The tapping port and slag outlet are located on the end furnace wall of the extended section on the side away from the furnace body; Preferably, the high-temperature gas inlet is connected to a plasma heating device or a combustion chamber. By setting an extended section and placing the taphole and slag outlet on one side of the extended end of the molten pool zone, the separation path between molten iron and steel slag is extended, allowing more time for slag-iron separation. This is suitable for smelting highly viscous iron ores and solves the problem of separating viscous slag. The high-temperature gas inlet also supplements the heat to the molten pool, ensuring that the temperature of the molten iron is maintained above the preset temperature. This structural design effectively solves the problem of incomplete slag-iron separation in viscous slag, and is particularly suitable for smelting difficult-to-separate ores such as high-phosphate ores and laterite nickel ores.

[0025] Preferably, the ore distribution device of the present invention is a multi-point distribution device, comprising multiple distribution units disposed at the top of the solid reduction zone, wherein the distribution units are respectively connected to the injection tank, the equalization tank and the distribution bin in sequence through distribution pipes; The injection tank and / or the material distribution pipe are provided with a carrier gas inlet to inject the furnace charge into the flash furnace through the material distribution unit. Preferably, the furnace charge is a mixture of iron ore powder and flux; Preferably, the furnace charge further includes carbon powder or coal powder; Preferably, multiple charging units are evenly arranged within the cross-section of the furnace body. By setting multiple charging units above the solid reduction zone and introducing carrier gas into the carrier gas inlet, the furnace charge is evenly injected into the flash blast furnace through the charging units, thereby making full use of the internal space of the furnace body, achieving uniform charge distribution within the furnace, and ensuring that the furnace charge is uniformly heated and reacted at all points on the same cross-section of the furnace body.

[0026] Preferably, the fabric unit of the present invention is a U-shaped fabric distributor, which includes a U-shaped tube, the end of which is bent upward to form a discharge port, and the discharge port is vertically upward or inclined upward. Preferably, a baffle plate is provided on the charge injection path of the U-shaped tube outlet. By setting multiple distribution points evenly distributed on the cross-section of the furnace and combining them with a unique "upward injection" method, the charge is injected into the furnace in multiple streams under the action of the carrier gas. Natural dispersion is achieved by gravity and collision, which effectively overcomes the drawbacks of the traditional "central column" type of charge feeding and realizes efficient mixing and heat exchange between the charge and the reducing gas.

[0027] By setting a baffle on the injection path of the discharge port, the upward-sprayed material flow actively impacts the baffle, forcing it to further disperse and change direction, resulting in a more ideal material distribution effect.

[0028] Preferably, the fabric distribution unit of the present invention is a steering wheel-type fabric distributor, which includes a feed pipe, a main air supply pipe, and an air supply ring pipe. The feeding pipe is connected to the rear end of the distribution pipe; the main air supply pipe enters the feeding pipe through an opening in the side wall of the feeding pipe and runs parallel to the feeding pipe, or the main air supply pipe is located outside the feeding pipe and runs downwards together with the feeding pipe; the air supply ring pipe is located at the end of the main air supply pipe and in the lower space of the feeding pipe, and multiple air jet holes are opened circumferentially on the pipe wall of the air supply ring pipe. By setting multiple feeding points evenly distributed on the cross-section of the furnace, and combining them with a unique air supply pipe equipped with several air jet holes, a lateral component of the distributed airflow is generated. The lateral component of the airflow is used to change the falling situation of the ore powder, so that the iron ore powder has lateral displacement kinetic energy, and finally the ore powder is laterally dispersed during the falling process. This effectively overcomes the drawbacks of the traditional "central column" feeding method and realizes efficient mixing and heat exchange between the furnace charge and the reducing gas.

[0029] The design of the air supply ring pipe effectively avoids the limitation of existing technology where materials can only diffuse outward in a circumferential direction, and increases the uniform distribution of materials falling in the central area. At the same time, by changing the distribution air pressure and flow rate and designing the upper and lower jet holes, the furnace charge is forced to be further dispersed and its direction changed during the descent process, resulting in a more ideal material distribution effect. This can further improve the space utilization rate of the smelting furnace, reduce costs and increase efficiency.

[0030] Preferably, the material distribution unit of the present invention is a side-wind material distributor, which includes a nozzle disposed on the top of the furnace body, the nozzle opening facing downward and being inclined. A feeding channel is provided above the nozzle, and the feeding channel is connected to the material distribution pipe; The nozzle sidewall is provided with a material distribution air channel, and the outlet of the material distribution air channel is inclined towards the nozzle opening. Through the reasonable distribution of multiple nozzles on the furnace body and top, combined with independent material distribution air channels, the furnace charge can be highly dispersed and uniformly distributed on the furnace cross section, avoiding local accumulation and creating the best initial conditions for efficient and uniform flash reaction.

[0031] This invention also discloses a co-current flash smelting method, utilizing the aforementioned co-current flash furnace, comprising the following steps: Mineral powder is injected into the reaction zone of the auxiliary furnace through the auxiliary furnace feed nozzle, where it exchanges heat and undergoes pre-reduction with the exhaust gas generated in the reaction zone of the main furnace. The pre-reduced ore powder rises with the tail gas to the gas-solid two-phase outlet and is discharged. After gas-solid separation, the pre-reduced ore powder is injected into the main furnace reaction zone through the ore material distribution device. At the same time, the reducing agent supply unit provides high-temperature reducing gas to the main furnace reaction zone. The reducing gas and ore powder are fully mixed and contacted in the main furnace reaction zone. The reducing gas reacts with the iron oxides in the ore powder to produce water vapor and molten iron and slag. The generated iron and slag fall into the lower molten pool area, where slag and iron are separated. The separated slag forms a slag layer in the upper part of the molten pool area, and the iron forms a molten iron layer in the lower part of the molten pool area. Slag is discharged periodically through the slag outlet, and molten iron is discharged through the iron outlet.

[0032] Compared with the prior art, the beneficial effects of the present invention are: 1. This solution directly connects the pre-reduction auxiliary furnace reaction zone with the main furnace reaction zone, forming an integrated and compact layout, which greatly reduces the equipment footprint. It is suitable for new projects and also facilitates low-cost retrofitting of existing blast furnaces.

[0033] 2. In terms of fluid organization, this scheme optimizes the airflow channel and material path. In the pre-reduction zone of the auxiliary furnace reaction zone, the airflow direction is upward and consistent with the movement direction of the mineral powder. Under the action of gravity, the coarse particles move slower than the fine particles and have a longer residence time, which is consistent with the logic that coarse particles have a longer reaction time. This effectively prolongs the residence time of mineral powder of each particle size in the reduction zone, enhances adaptability, and improves the degree of pre-reduction.

[0034] 3. The direct connection between the auxiliary furnace reaction zone and the main furnace reaction zone makes full use of the pressure and temperature of the tail gas in the main furnace reaction zone, realizes the continuous connection between pre-reduction and final reduction in space, significantly reduces heat loss, and greatly improves heat utilization efficiency.

[0035] While maintaining the inherent advantages of flash ironmaking, such as direct utilization of fine ore, molten iron as the product, and wide applicability of materials, this solution significantly improves the stability of the process and its adaptability to different particle sizes of ore powder, providing a better solution for the industrial application of flash ironmaking technology. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the co-current flash blast furnace described in Example 1; Figure 2 This is a schematic diagram of the co-current flash blast furnace described in Example 2; Figure 3 This is a schematic diagram of the co-current flash blast furnace described in Example 3; Figure 4 This is a schematic diagram of the co-current flash blast furnace described in Example 4; Figure 5This is a schematic diagram of the co-current flash blast furnace described in Example 5; Figure 6 This is a schematic diagram of the co-current flash blast furnace described in Example 6; Figure 7 Schematic diagram of the reducing gas injection inlet in the combustion chamber Figure 1 ; Figure 8 Schematic diagram of the reducing gas injection inlet in the combustion chamber Figure 2 ; Figure 9 Schematic diagram of the reducing gas injection inlet in the combustion chamber Figure 3 ; Figure 10 This is a schematic diagram of a hydrogen production device. Figure 11 Schematic diagram of a steering wheel-type fabric feeder Figure 1 ; Figure 12 This is a schematic diagram of the crosswind material distributor. Figure 13 This is a schematic diagram of the U-shaped fabric feeder. Figure 14 Schematic diagram of the steering wheel fabric structure Figure 2 ; In the diagram, 1 is the furnace body, 2 is the ore feeding device, 3 is the reducing agent supply unit, and 4 is the auxiliary furnace feeding nozzle. 101 Main furnace reaction zone, 102 Auxiliary furnace reaction zone, 103 Molten pool zone; 1031 Slag outlet, 1032 Iron outlet, 1021 Gas-solid two-phase outlet, 1033 Extended section, 1034 Carbon raiser spray gun; 5. Gas-solid separation efficiency improvement device, 51. Flow hole, 6. Furnace shell inner diameter change section, 7. Reheating unit, 8. Hot reducing gas supply unit, 81. Combustion chamber, 82. Plasma heating device. 9 Reducing gas supply device, 10 First dust collector, 11 Heat exchange device, 12 Carbon dioxide removal device, 13 Hydrogen exchange device; 14 Exhaust gas reforming unit, 15 Fabric distribution unit, 16 Fabric distribution pipe, 17 Fabric distribution bin; 18 Second dust collector; 19 Dehydration device; 20 mineral powder drying unit, 201 ore bin, 202 fluidized bed; 1000 U-type material distributor, 2000 steering wheel type material distributor, 3000 side wind material distributor; 1001 U-shaped pipe, 1002 mineral material baffle, 1003 pipe dredging; 2001 Feed pipe, 2002 Main air supply pipe, 2003 Air supply ring pipe, 2004 Air jet hole; 3001 Nozzle, 3002 Feed Channel, 3003 Fabric Air Channel; 100 First furnace body, 200 partition wall, 300 Second furnace body, 400 Third furnace body; 21 Auxiliary furnace ore powder preheating system, 211 ore powder silo, 212 first injection tank group, 22 hot ore powder feeding system, 221 hot ore powder silo, 222 second injection tank group; 23 Fuel supply device, 24 Oxygen supply device. Detailed Implementation

[0037] The technical solutions in the embodiments of the present invention will now be clearly and completely described in conjunction with the accompanying drawings.

[0038] Example 1 The following is based on Figure 1 The present invention will be described in detail below so that those skilled in the art can readily implement it. The present invention may be embodied in many different forms and is not limited thereto.

[0039] Raw material conditions used in smelting:

[0040] The auxiliary furnace reaction zone is directly connected to the main furnace reaction zone. The connection point is located in the lower part of the main furnace reaction zone. At least one auxiliary furnace feed nozzle 4 is provided in the lower part of the auxiliary furnace reaction zone, and a gas-solid two-phase outlet is provided at the top. The furnace gas in the main furnace reaction zone is used to pre-reduce the ore.

[0041] Specifically, in this embodiment, as Figure 1 As shown, the furnace body 1 includes a second furnace body 300 and a third furnace body 400.

[0042] The lower end of the third furnace body 400 is connected to the side wall of the second furnace body 300. Specifically, the lower end of the third furnace body 400 is inclined downwards and connected to the side wall of the second furnace body 300. The main furnace reaction zone 101 and the molten pool zone 103 are arranged from top to bottom within the second furnace body 300, and the auxiliary furnace reaction zone 102 is located within the third furnace body 400. In this embodiment, the main furnace reaction zone is a space enclosed by a metal shell and cooling elements and refractory materials installed on the metal shell, used for the flash reduction reaction and smelting of iron ore powder.

[0043] A gas-solid separation efficiency-enhancing device 5 is installed on the lower side wall of the main furnace reaction zone 101.

[0044] The gas-solid separation efficiency improvement device 5 includes an annular baffle wall disposed on the inner wall of the furnace body and a flow passage 51 disposed in the center of the annular baffle wall.

[0045] At the flow passage, the flow area of ​​the furnace cavity is reduced, and the area is 5% to 50% of the inner diameter area of ​​the main furnace reaction zone 101.

[0046] In this embodiment, a tail gas reforming unit 14 is provided on the side wall of the auxiliary furnace reaction zone 102 near the connection with the main furnace reaction zone 101 to increase the reducing gas content in the tail gas. The tail gas reforming unit 14 is a pulverized coal injection gun or a pulverized coal and steam injection gun.

[0047] The reducing gas supply device 9 is a gas generator, which produces reducing gas (CO+H2≥90%). The produced reducing gas is sent to the plasma heating device 82. Hydrogen is heated to 1600℃ by plasma heating and then sent to the reducing agent supply unit 3. The plasma heating device 82 is a furnace body that extends outward to form one or more plasma chambers, with the shell of the plasma chamber replacing the shell of the plasma torch.

[0048] Iron ore powder and dolomite from the raw material yard are mixed in proportion and transported to the powder silo of the auxiliary furnace powder preheating system 21. The iron ore powder in the powder silo 211 is sent to the auxiliary furnace feed nozzle 4, i.e., the powder nozzle, located in the middle of the auxiliary furnace reaction zone 102, through the first injection tank group 212 and injected into the auxiliary furnace reaction zone 102. The first injection tank group 212 includes a pressure equalization tank and an injection tank arranged from top to bottom. The tail gas generated by the flash furnace reaction is first cooled to 900°C in the auxiliary furnace reaction zone 102 after waste heat recovery. The 900°C tail gas exchanges heat and pre-reduces with the iron ore powder injected through the powder nozzle. When the iron ore powder rises with the tail gas to the outlet of the auxiliary furnace reaction zone 102, i.e., the gas-solid two-phase outlet 1021, the iron ore powder is heated to 500°C~700°C and the reduction degree reaches 15%. The gas-solid two-phase gas discharged from the auxiliary furnace reaction zone 102... The mixture is purified by the first dust collector 10 (using a cyclone dust collector), the heat exchange device 11 (if the exhaust gas temperature is >260℃), and the second dust collector 18 (using a bag filter). It then enters the carbon dioxide removal device 12 to remove CO2 and moisture, and is sent as reducing gas to the outlet of the reducing gas supply device 9. It then enters the plasma heating device for heating. The iron ore powder collected by the first dust collector 10 and the second dust collector 18 is sent to the hot ore powder bin of the hot ore powder feeding system, and then sent to the ore distribution device 2 through the injection tank group. The ore distribution device 2 is a multi-point distribution device, including multiple distribution units 15 set at the top of the solid reduction zone. The distribution units are connected to the injection tank, the equalizing tank, and the distribution bin 17 in sequence through the distribution pipe 16. The multiple distributors are evenly arranged in the cross-section of the furnace body.

[0049] The injection tank and / or the material distribution pipe 16 are provided with a carrier gas inlet to inject the furnace charge into the flash furnace through the material distribution unit.

[0050] like Figure 13As shown, in this embodiment, the material distribution unit 15 is a U-shaped material distributor 1000, which is installed on the upper part of the main furnace reaction zone 101. The U-shaped material distributor 1000 includes a U-shaped tube 1001. The end of the U-shaped tube 1001 is bent upward to form a discharge port. The discharge port is set vertically upward or inclined upward to spray iron ore powder upward and spread it evenly, and then it falls down.

[0051] A ore baffle 1002 is provided on the furnace charge injection path of the U-shaped tube 1001 outlet, and the ore baffle 1002 is fixedly installed inside the furnace body 1.

[0052] To prevent blockages in individual distribution pipes, each distribution pipe is equipped with two purging air inlets. These inlets connect to purging pipe 1003, through which purging air is introduced. This purging air can be used as auxiliary gas supply during normal production, or for immediate purging and clearing when a blockage is detected. Flow and pressure gauges are installed on the purging air pipes to monitor and locate blocked sections in real time.

[0053] In this embodiment, the lower part of the silo is connected to the equalizing tank via a valve, and the equalizing tank is connected to the injection tank via a valve located at its lower part. An air carrier pipe is installed on the injection tank, and the initial ends of multiple material distribution pipes are connected to the lower part of the injection tank.

[0054] In the main furnace reaction zone 101, reducing gas and iron ore powder are thoroughly mixed and in contact. As the iron ore powder falls with hydrogen in the main furnace reaction zone 101, it exchanges heat with the hydrogen, heating the iron ore powder. The hydrogen reacts with the iron oxides in the iron ore powder to produce water vapor and molten iron and slag. During its downward flow, the gas and liquid pass through the throat structure, i.e., the flow orifice 51, at the lower part of the main furnace reaction zone 101. At the throat, the velocity of the slag, iron, and tail gas increases, accelerating the separation of molten slag, iron, and tail gas. The average falling velocity of the iron ore powder in the main furnace reaction zone 101 is 3~4 m / s; the residence time of the iron ore powder in the main furnace reaction zone 101 is 4~6 s.

[0055] The generated iron and slag fall into the lower molten pool zone 103, where slag and iron are separated. The separated slag forms a slag layer on the upper part of the molten pool zone 103, and the iron forms a molten iron layer on the lower part of the molten pool zone 103. The slag is discharged periodically through the slag outlet 1031, and the molten iron is discharged through the tapping outlet 1032. The tail gas generated by the reaction (mainly composed of CO, CO2, H2, and H2O) is cooled in the auxiliary furnace reaction zone 102. The tail gas temperature is reduced from 1500℃ to 900℃ through the waste heat recovery in the lower section of the auxiliary furnace reaction zone 102. Then, iron ore powder is injected into the tail gas at 900℃ through the ore powder spray gun. The 900℃ tail gas and iron ore powder exchange heat and undergo pre-reduction in the upper section of the auxiliary furnace reaction zone 102. In this embodiment, the auxiliary furnace reaction zone 102 is set up to cool the tail gas and make full use of the heat and kinetic energy of the tail gas. The furnace body 1 is a vertical furnace structure, which can effectively reduce the floor space and increase the temperature of the molten pool.

[0056] The purpose of spraying the recarburizer into the slag-iron interface of the molten pool zone 103 by the recarburizer spray gun 1034 is twofold: first, to further reduce the iron oxides in the slag (the iron ore powder in the main furnace reaction zone 101 was not completely reduced to metallic iron, and there is still some FeO); and second, to adjust the carbon content of the molten iron to obtain products with different carbon contents (the carbon content of iron is >2.11%, and the carbon content of steel is <2.11%).

[0057] In order to adjust the slag composition to obtain smelting slag with good fluidity and stability, lime is injected into the reaction zone 101 of the main furnace through a lime injection system to adjust the binary basicity (CaO / SiO2) of the slag by 1.0 to 1.2 times.

[0058] To supplement the heat required for the reduction reaction and slag-iron melting in the main furnace reaction zone 101, two combustion chambers, namely combustion chamber 81, are set in the lower part of the main furnace reaction zone 101 as a heat supplement unit 7. The oxygen required for combustion is supplied by an oxygen supply device, and the oxygen supplied by the oxygen supply device is a by-product of the water electrolysis hydrogen production device.

[0059] In addition, in order to recover and reuse the reducing gases in the exhaust gas, such as Figure 10 As shown, the air outlet of the first dust collector 10 is connected to the hot side inlet of the heat exchange device 11.

[0060] The hot-side outlet of the heat exchange device 11 is connected to the inlet of the second dust collector. One outlet of the second dust collector is connected to the external supply network through a pressure regulating valve group, and the other outlet is connected to the carbon dioxide removal device 12 and the dehydration device in sequence. The outlet of the dehydration device is connected to the inlet of the circulating fan, the outlet of the circulating fan is connected to the cold-side inlet of the heat exchange device 11, and the cold-side outlet of the heat exchange device 11 is connected to the inlet of the hot reducing gas supply unit 8.

[0061] A sulfur dioxide removal device is installed between the hot side outlet of the heat exchange device 11 and the second dust collector.

[0062] A hydrogen conversion device 13 is installed between the outlet of the second dust collector and the carbon dioxide removal device 12.

[0063] Example 2 The following is based on Figure 2 For reference, the difference from Example 1 is as follows: The main furnace reaction zone 101 is provided with a sudden change section 6 in the inner diameter of the furnace shell. The furnace diameter suddenly changes a large rate of change, and then gradually decreases. The section area increases by 10% to 50% to prevent the molten material from sticking to the furnace wall and causing the section area to shrink.

[0064] like Figure 11As shown, the fabric distribution unit is a steering wheel-type fabric distributor 2000; the steering wheel-type fabric distributor includes a feed pipe 2001, a main air supply pipe 2002, and an air supply ring pipe 2003.

[0065] The feeding pipe 2001 is connected to the rear end of the material distribution pipe 16; the main air supply pipe 2002 enters the feeding pipe through the opening in the side wall of the feeding pipe 2001 and runs in the same direction as the feeding pipe; the air supply ring pipe 2003 is located at the end of the main air supply pipe and in the lower space of the feeding pipe. The air supply ring pipe 2003 is horizontally arranged in the furnace body, and multiple air jet holes 2004 are opened circumferentially on the pipe wall of the air supply ring pipe 2003.

[0066] The jet nozzle 2004 can be disposed on the outer ring side wall of the air supply ring pipe 2003 or on the inner ring side wall of the air supply ring pipe 2003. The jet nozzle 2004 is arranged radially through the wall of the air supply ring pipe 2003 to provide lateral dispersion force for the furnace charge, thereby achieving the effect of dispersed material distribution.

[0067] To improve the uniformity of air distribution, multiple layers of annularly distributed jet holes 2004 can be installed on the air supply ring pipe 2003.

[0068] To improve fabric uniformity, in this embodiment, the air jet holes 2004 are evenly distributed in a ring along the circumference of the air supply ring pipe 2003.

[0069] like Figure 2 As shown, in this embodiment, the reducing agent supply unit 3 is a reducing gas inlet and a hot reducing gas supply unit 8.

[0070] The reducing gas inlet is connected to the hot reducing gas supply unit 8.

[0071] The heat reduction gas supply unit 8 includes at least one combustion chamber 81 connected to the furnace body 1.

[0072] The combustion chamber 81 is provided with a combustion cavity. A combustion nozzle is provided at one end of the combustion chamber 81 along its axial direction, and a reducing gas outlet is provided at the other end. The reducing gas outlet is connected to the reducing gas inlet on the side wall of the furnace body. The combustion chamber 81 is composed of a steel plate shell, an inner refractory lining, and water-cooled walls where necessary.

[0073] The combustion nozzle is equipped with a fuel inlet and an auxiliary combustion gas inlet; the fuel inlet and the auxiliary combustion gas inlet are respectively connected to the fuel supply device 23 and the oxygen supply device 24. The fuel is pulverized coal, coal gas or natural gas, and the auxiliary combustion gas is pure oxygen or oxygen-enriched gas.

[0074] like Figures 7-9 As shown, at least one reducing gas injection inlet is provided at the combustion end and / or side wall of the combustion chamber 81. The reducing gas injected through the reducing gas injection inlet flows closely to the circumferential side wall of the combustion chamber 81 to form an air curtain.

[0075] Specifically, such as Figure 7 As shown, when the reducing gas injection inlet is located on the inner wall of the combustion chamber, there are multiple reducing gas injection inlets. These multiple reducing gas injection inlets are arranged around the circumferential wall surface of the inner wall of the combustion chamber 81, so that the reducing gas to be heated injected forms a complete cooling air curtain on the inner wall of the combustion chamber 81.

[0076] like Figure 8 As shown, when the reducing gas injection inlet is located at the combustion end of the combustion chamber 81, there are multiple reducing gas injection inlets. These multiple reducing gas injection inlets are arranged around the combustion nozzle and distributed in a ring along the axis of the combustion chamber 81, so that the reducing gas to be heated ejected forms a complete cooling air curtain on the inner wall of the combustion chamber 81.

[0077] like Figure 9 As shown, the reducing gas injection inlet forms an angle with the axial direction of the combustion chamber, forming a spiral cooling gas curtain and increasing the travel distance of the reducing gas within the combustion chamber.

[0078] When molten iron in the furnace needs to be carburized, the required excess pulverized coal is injected through a combustion lance.

[0079] Example 3 The following is based on Figure 3 For reference, the difference from Example 1 is as follows: The molten pool zone 101 is horizontally extended by a section 1033. An iron tapping port 1032 and a slag tapping port 1031 are located on the furnace wall at the end of the extended section 1033. A plasma chamber or combustion chamber is located on the furnace wall or top at the end of the extended section 1033 to supplement heat. This design is suitable for smelting special ores such as vanadium-titanium iron ore and red mud high-alumina iron ore. Because their smelting slag contains high levels of TiO2 or Al2O3, the slag viscosity is high, making slag-iron separation difficult. Extending the molten pool increases the slag-iron separation time, and adding a combustion chamber further heats the molten pool, increases the molten pool temperature, and reduces slag viscosity.

[0080] like Figure 12 As shown, unlike Embodiment 1, the material distribution unit 15 is a side air distributor 3000; the side air distributor 3000 includes a nozzle 3001 disposed on the furnace top, the nozzle opening facing downward and inclined.

[0081] A feeding channel 3002 is provided above the nozzle, and the feeding channel 3002 is connected to the material distribution pipe 16.

[0082] The nozzle sidewall is provided with a fabric air channel 3003, and the outlet of the fabric air channel is inclined toward the nozzle opening. The fabric air channel 3003 is connected to the fabric air system.

[0083] Example 4 The following is based on Figure 4 For reference, the difference from Example 1 is as follows: The furnace body 1 includes a first furnace body 100 and a partition wall 200.

[0084] The first furnace body 100 is vertically arranged, and the partition wall 200 is located above the first furnace body 100, dividing the space above the first furnace body 100 into a main furnace reaction zone 101 and an auxiliary furnace reaction zone 102. The space below the first furnace body 100 is the molten pool zone 103. That is, the main furnace reaction zone 101 and the auxiliary furnace reaction zone 102 are in the same furnace shell, separated by an internal intermediate wall but connected at the bottom to form the main furnace reaction zone 101 and the auxiliary furnace reaction zone 102. This design has a more compact structure, significantly reducing the equipment footprint and lowering costs.

[0085] Example 5 The difference from Example 1 is that in Example 5, the reducing gas supply device is hydrogen production by water electrolysis, which requires subsequent dehydration; while in Example 1, the reducing gas supply device is a coal gas generator, which requires the removal of CO2 and H2O.

[0086] In Example 5, the exhaust gas from the auxiliary furnace reaction zone 102 passes through a cyclone dust collector and enters the mineral powder drying unit 20, which uses a circulating fluidized bed mode.

[0087] In Example 1, the exhaust gas passes through a cyclone dust collector and then enters a bag filter dust collector; if the exhaust gas temperature is too high, a heat exchanger (not shown in the figure) is installed.

[0088] The following is based on Figure 5 The present invention will be described in detail below so that those skilled in the art can readily implement it. The present invention may be embodied in many different forms and is not limited thereto.

[0089] The reducing gas supply device 9 is for hydrogen production by water electrolysis. It uses renewable electricity (green electricity) to produce hydrogen through the water electrolysis device. The produced hydrogen is sent to the plasma heating device 82. The hydrogen is heated to 2000°C by plasma heating and then sent to the reducing agent supply unit 3. The plasma heating device is a furnace body that extends outward to form one or more plasma chambers, with the shell of the plasma chamber replacing the shell of the plasma torch.

[0090] Iron ore powder and dolomite from the raw material yard are mixed in proportion and transported to ore bin 201. The feeder under ore bin 201 feeds the powder into the circulating fluidized bed drying and preheating system. The tail gas generated from flash furnace smelting is cooled to 500℃ in the auxiliary furnace reaction zone 102 of the pre-reduction system, and then the 500℃ tail gas is sent to the inlet pipe of fluidized bed 202. In the circulating fluidized bed system, the iron ore powder drying and preheating process involves feeding the iron ore powder into the first venturi tube, and after passing through the first venturi tube, the gas-solid mixture enters the first cyclone dust collector. After gas-solid separation in the first cyclone dust collector, the iron ore powder is fed into the second venturi tube through the first L valve, and after passing through the second venturi tube, the gas-solid mixture enters the second cyclone dust collector. After gas-solid separation in the second cyclone dust collector... Iron ore powder is fed into fluidized bed 202, and gas enters the first venturi tube. The tail gas from the auxiliary furnace reaction zone 102 of the flash furnace enters from the inlet pipe at the bottom of fluidized bed 202. The iron ore powder is fluidized, dried and preheated in fluidized bed 202. Then the gas is discharged from the upper part of the fluidized bed and enters the third cyclone dust collector for gas-solid separation. The gas enters the second venturi tube. The iron ore powder after gas-solid separation is fed into fluidized bed 202 through the second L-type valve. The iron ore powder dried and preheated in the fluidized bed is sent to the iron ore powder silo of the auxiliary furnace iron ore powder preheating system 21. The iron ore powder in the iron ore powder silo is sent to the iron ore powder spray gun set in the middle of the auxiliary furnace reaction zone 102 through the second injection tank group and sprayed into the auxiliary furnace reaction zone 102 for pre-reduction. The exhaust gas generated by the flash furnace reaction is first cooled to 900°C in the auxiliary furnace reaction zone 102 after waste heat recovery. The 900°C exhaust gas exchanges heat and pre-reduces with the iron ore powder injected through the ore powder spray gun. When the iron ore powder rises with the exhaust gas to the outlet of the auxiliary furnace reaction zone 102, the iron ore powder is heated to 500°C~700°C and the reduction degree reaches 15%. The iron ore powder collected by the cyclone dust collector of the first dust collector 10 and the bag dust collector of the second dust collector 18 is sent to the hot ore powder silo 221 of the hot ore powder feeding system 22, and then sent to the ore material distribution device 2 through the second injection tank group 222. The second injection tank group 222 includes a pressure equalization tank and an injection tank arranged from top to bottom.

[0091] In the main furnace reaction zone 101, hydrogen and iron ore powder are thoroughly mixed and in contact. As the iron ore powder falls with the hydrogen in the main furnace reaction zone 101, it exchanges heat with the hydrogen, heating the iron ore powder. The hydrogen reacts with the iron oxides in the iron ore powder in a reduction reaction, generating water vapor and molten iron and slag. During its downward flow, the gas and liquid pass through the throat structure at the lower part of the main furnace reaction zone 101. At the throat, the velocity of the slag, iron, and tail gas increases, accelerating the separation of molten slag, iron, and tail gas. The average falling velocity of the iron ore powder in the main furnace reaction zone 101 is 2~5 m / s; the residence time of the iron ore powder in the main furnace reaction zone 101 is 2~8 s.

[0092] The generated iron and slag fall into the lower molten pool zone 103, where slag and iron are separated. The separated slag forms a slag layer in the upper part of the molten pool, and the iron forms a molten iron layer in the lower part of the molten pool. The slag is discharged through the slag outlet at regular intervals, and the molten iron is discharged through the tapping outlet. The tail gas (water vapor and excess hydrogen) generated by the reaction is cooled from 1500°C to 500°C in the auxiliary furnace reaction zone 102, and then sent to the inlet pipe of the ore powder drying unit 20 (in this embodiment, a fluidized bed pre-reduction system is selected).

[0093] The exhaust gas discharged from the first cyclone dust collector is purified by the bag filter, which serves as the second dust collector 18, and then sent to the dehydration device 19 for dehydration to obtain hydrogen and water. The hydrogen is pressurized and then fed into the pipeline after the reducing gas supply device 9 and sent to the plasma heating device 82. The iron ore powder collected by the bag filter, which serves as the second dust collector 18, is sent to the hot ore powder feeding system.

[0094] The purpose of spraying the recarburizer into the slag-iron interface of the molten pool zone 103 by the recarburizer spray gun 1034 is twofold: first, to further reduce the iron oxides in the slag (the iron ore powder in the main furnace was not completely reduced to metallic iron, and there is still some FeO); and second, to adjust the carbon content of the molten iron to obtain products with different carbon contents (the carbon content of iron is >2.11%, and the carbon content of steel is <2.11%).

[0095] In order to adjust the slag composition and obtain smelting slag with good fluidity and stability, lime is injected into the reaction zone 1011 of the main furnace through a lime injection system to adjust the binary basicity (CaO / SiO2) of the slag by 1.0 to 1.2 times.

[0096] To supplement the heat required for the reduction reaction and slag-iron melting in the main furnace reaction zone 101, two combustion chambers are set in the lower part of the main furnace reaction zone 101. The oxygen required for combustion is supplied by an oxygen supply device, and the oxygen supplied by the oxygen supply device is a byproduct of the water electrolysis hydrogen production device.

[0097] Example 6 The following is based on Figure 6 The present invention will be described in detail below so that those skilled in the art can readily implement it. The present invention may be embodied in many different forms and is not limited thereto.

[0098] The difference from Example 4 is that: 1) The reducing gas supply device 9 is a gas generator, and the reducing gas (CO+H2≥85%) produced by it is used as the reducing gas; 2) The exhaust gas discharged from the circulating fluidized bed pre-reduction system is purified by a bag filter and then sent to the carbon dioxide removal device 12 to remove CO2 and H2O from the exhaust gas, and then used as reducing gas. 3) The fuel supply device (pulverized coal) and oxygen supply device send the fuel to the burner for combustion, and the generated high-temperature gas enters the main furnace reaction zone 101.

[0099] Example 7 like Figure 14 As shown, the difference from Embodiment 1 is that the air supply main pipe 2002 is located outside the discharge pipe 2001 and runs downward together with the discharge pipe.

Claims

1. A co-current flash furnace, characterized in that: It includes a furnace body (1), a ore feeding device (2), a reducing agent supply unit (3), and an auxiliary furnace feeding nozzle (4); The furnace body (1) includes a main furnace reaction zone (101), an auxiliary furnace reaction zone (102), and a molten pool zone (103). The molten pool zone (103) is located at the lower part of the furnace body (1). The main furnace reaction zone (101) and the auxiliary furnace reaction zone (102) are located above the molten pool zone (103), and the lower end of the auxiliary furnace reaction zone (102) is directly connected to the lower end of the main furnace reaction zone (101). The main furnace reaction zone (101) is provided with a solid reduction zone, a soft melting reduction zone and a liquid zone from top to bottom; The upper part of the main furnace reaction zone (101) is provided with a ore feeding device (2) and a reducing agent supply unit (3), the reducing agent supply unit (3) being used to provide the reducing gas and heat required for the reaction; The auxiliary furnace reaction zone (102) is provided with a gas-solid two-phase outlet (1021) at the top, and at least one auxiliary furnace feed nozzle (4) is provided in the lower part of the auxiliary furnace reaction zone (102). The molten pool zone (103) includes a slag layer and a molten iron layer; the sidewall of the molten pool zone (103) is provided with a slag outlet (1031) and an iron outlet (1032).

2. The co-current flash furnace as described in claim 1, characterized in that: A gas-solid separation efficiency-enhancing device (5) is provided on the lower side wall of the main furnace reaction zone (101). The gas-solid separation efficiency improvement device (5) includes an annular baffle wall disposed on the inner wall of the furnace body and a flow hole (51) disposed in the center of the annular baffle wall. Preferably, at the flow passage, the flow area of ​​the furnace cavity is reduced, and the area is 5% to 50% of the inner diameter area of ​​the main furnace reaction zone (101); Preferably, the gas-solid separation efficiency improvement device (5) includes several layers of annular baffles arranged from top to bottom in the main furnace reaction zone (101).

3. The co-current flash furnace as described in claim 1, characterized in that: The main furnace reaction zone (101) near the part that enters the softening and reduction zone is provided with a sudden change section (6) in the inner diameter of the furnace shell. Preferably, the maximum flow area at the abrupt change section (6) of the furnace shell is 10% to 50% larger than the cross-section of the main furnace reaction zone (101) above it, and the flow area expansion section extends to the liquid zone.

4. The co-current flash furnace as described in claim 1, characterized in that: A supplementary heating unit (7) is provided in the middle and / or lower part of the main furnace reaction zone (101). Preferably, a carbon raiser spray gun (1034) is inserted into the slag layer of the molten pool zone (103). Preferably, the heating unit (7) is a heating spray gun, a heating flue gas inlet, or a reducing gas inlet, and the heating spray gun is connected to the fuel supply device and the combustion gas supply device; Preferably, the fuel used in the fuel supply device is pulverized coal, natural gas, or coal gas, and the combustion-supporting gas used in the combustion-supporting gas supply device is pure oxygen or oxygen-enriched air.

5. The co-current flash furnace as described in claim 1, characterized in that: The reducing agent supply unit (3) is a reducing gas inlet and a hot reducing gas supply unit (8). The reducing gas inlet is located on the side wall of the furnace body (1) and is connected to the hot reducing gas supply unit (8). The heat reducing gas supply unit (8) is used to heat the reducing gas; Preferably, the heat reduction gas supply unit (8) includes at least one combustion chamber (81) connected to the furnace body (1). The combustion chamber (81) is provided with a combustion cavity, and a combustion nozzle is provided at one end of the combustion chamber (81) along the axial direction, and a reducing gas outlet is provided at the other end. The reducing gas outlet is connected to the reducing gas inlet on the side wall of the furnace body. The combustion nozzle is equipped with a fuel inlet and an auxiliary combustion gas inlet; at least one reducing gas injection inlet is provided at the combustion end or side wall of the combustion chamber; Preferably, the reducing gas supplied by the reducing gas injection inlet flows closely against the circumferential sidewall of the combustion chamber (81) to form an air curtain; Preferably, the reducing gas injection inlet forms an angle with the axial direction of the combustion chamber (81) to form a spiral gas curtain; Preferably, when the molten iron in the furnace needs to be carburized, the required excess pulverized coal is injected through a combustion lance; Preferably, the heat reducing gas supply unit (8) includes at least one plasma heating device (82) connected to the reducing gas inlet. Alternatively, the reducing agent supply unit (3) may be a composite spray gun containing carbon fuel and oxygen-containing combustion gas, which generates reducing hot flue gas through incomplete combustion in the furnace; Preferably, the carbon-containing fuel is pulverized coal, coal gas, or natural gas, and the oxygen-containing combustion-supporting gas is pure oxygen or oxygen-enriched gas.

6. The co-current flash furnace as described in claim 5, characterized in that: The heat reducing gas supply unit (8) is connected to the reducing gas supply device (9); Preferably, the reducing gas supply device (9) is one or a combination of one or more of the following: a coal gas generator or a coal-to-hydrogen device, an electrolytic hydrogen device, a coke oven gas-to-hydrogen device, a methanol-to-hydrogen device, and an ammonia-to-hydrogen device.

7. The co-current flash furnace as described in claim 1, characterized in that: The auxiliary furnace feed nozzle (4) is connected to the mineral powder drying unit (20); The mineral powder drying unit (20) is connected to the crushing and grinding device; Preferably, the mineral powder drying unit (20) is a rotary kiln, a bubbling fluidized bed, or a circulating fluidized bed; Preferably, the mineral powder drying unit (20) is connected to the gas-solid two-phase outlet (1021) and uses the waste heat of the system tail gas for drying.

8. The co-current flash furnace as described in claim 1, characterized in that: The gas-solid two-phase outlet (1021) is connected to the first dust collector (10); The discharge port of the first dust collector (10) is connected to the hopper of the ore distribution device (2); Preferably, the air outlet of the first dust collector (10) is connected to the hot-side inlet of the heat exchange device (11); The heat exchange device (11) has its hot side outlet connected to the inlet of the second dust collector. One outlet of the second dust collector is connected to the external supply network through a pressure regulating valve group, and the other outlet is connected to the carbon dioxide removal device (12) and the dehydration device in sequence. The outlet of the dehydration device is connected to the inlet of the circulating fan, and the outlet of the circulating fan is connected to the cold side inlet of the heat exchange device (11). The cold side outlet of the heat exchange device (11) is connected to the inlet of the heat reduction gas supply unit (8). Preferably, a sulfur dioxide removal device is provided between the hot side outlet of the heat exchange device (11) and the second dust collector; Preferably, a hydrogen conversion device (13) is provided between the outlet of the second dust collector and the carbon dioxide removal device (12).

9. The co-current flash furnace as described in claim 1, characterized in that: On the side wall of the auxiliary furnace reaction zone (102) close to the connection with the main furnace reaction zone (101), there is a tail gas reforming unit (14) to increase the content of reducing gas in the tail gas; Preferably, the exhaust gas reforming unit (14) is a pulverized coal spray gun or a pulverized coal and steam composite spray gun.

10. The co-current flash furnace as described in claim 1, characterized in that: The furnace body (1) includes a first furnace body (100) and a partition wall (200); The first furnace body (100) is vertically arranged, and the partition wall (200) is located above the first furnace body (100), dividing the space above the first furnace body (100) into the main furnace reaction zone (101) and the auxiliary furnace reaction zone (102). The space below the first furnace body (100) is the molten pool zone (103). Alternatively, the furnace body (1) may include a second furnace body (300) and a third furnace body (400). The lower end of the third furnace body (400) is connected to the side wall of the second furnace body (300). The main furnace reaction zone (101) and the molten pool zone (103) are arranged from top to bottom in the second furnace body (300), and the auxiliary furnace reaction zone (102) is located in the third furnace body (400). Preferably, the furnace body (1) is based on a blast furnace; The structure above the hearth of the blast furnace body serves as the main furnace reaction zone (101), the hearth of the blast furnace serves as the molten pool zone (103), and a new furnace body connected to the lower part of the main furnace reaction zone (101) serves as the auxiliary furnace reaction zone (102). Alternatively, a partition wall with a cooling wall can be added inside the blast furnace body to form the main furnace reaction zone (101) and the auxiliary furnace reaction zone (102).

11. The co-current flash furnace as described in claim 1, characterized in that: The molten pool region (103) is provided with an extended section (1033) in the horizontal direction; The extended section (1033) is provided with a high-temperature gas inlet or a supplementary heating gas raw material supply device at the end of the side away from the furnace body (1); The tapping port (1032) and the slag outlet (1031) are located on the end furnace wall of the extended section (1033) on the side away from the furnace body (1); Preferably, the high-temperature gas inlet is connected to a plasma heating device or a combustion chamber.

12. The co-current flash furnace as described in any one of claims 1 to 11, characterized in that: The ore distribution device (2) is a multi-point distribution device, including multiple distribution units (15) set at the top of the solid reduction zone. The distribution units are connected to the injection tank, the equalization tank and the distribution bin (17) in sequence through the distribution pipe (16). The injection tank and / or the material distribution pipe (16) are provided with a carrier gas inlet to inject the furnace charge into the flash furnace through the material distribution unit; Preferably, the furnace charge is a mixture of iron ore powder and flux; Preferably, the furnace charge further includes carbon powder or coal powder; Preferably, multiple fabric units (15) are evenly arranged within the cross-section of the furnace body.

13. The co-current flash furnace as described in claim 12, characterized in that: The fabric unit (15) is a U-shaped fabric feeder (1000), which includes a U-shaped tube (1001). The end of the U-shaped tube (1001) is bent upward to form a discharge port, which is vertically or inclined upward. Preferably, a ore baffle (1002) is provided on the furnace charge injection path of the U-shaped tube (1001) outlet, and the ore baffle (1002) is fixedly installed inside the furnace body (1).

14. The co-current flash furnace as described in claim 12, characterized in that: The fabric unit (15) is a steering wheel type fabric distributor (2000), which includes a feed pipe (2001), an air supply main pipe (2002), and an air supply ring pipe (2003). The feed pipe (2001) is connected to the rear end of the fabric distribution pipe (16); the air supply main pipe (2002) enters the feed pipe through the opening in the side wall of the feed pipe (2001) and runs in the same direction as the feed pipe, or the air supply main pipe (2002) is located outside the feed pipe (2001) and runs downward together with the feed pipe; the air supply ring pipe (2003) is located at the end of the air supply main pipe (2002) and in the lower space of the feed pipe (2001), and multiple air jet holes (2004) are opened circumferentially on the pipe wall of the air supply ring pipe (2003).

15. The co-current flash furnace as described in claim 12, characterized in that: The material distribution unit (15) is a side air distributor (3000), which includes a nozzle (3001) disposed on the top of the furnace body (1). The nozzle (3001) is set with its opening facing downward and tilted. A feeding channel (3002) is provided above the nozzle (3001), and the feeding channel (3002) is connected to the material distribution pipe (16); The nozzle (3001) has a fabric air channel (3003) on its side wall, and the outlet of the fabric air channel (3003) is inclined toward the opening of the nozzle (3001).

16. A co-current flash smelting method, utilizing the co-current flash furnace according to any one of claims 1 to 15, characterized in that, Includes the following steps: The mineral powder is injected into the auxiliary furnace reaction zone (102) through the auxiliary furnace feed gun (4) and exchanged heat with the tail gas generated by the reaction in the main furnace reaction zone (101) for pre-reduction; The pre-reduced ore powder rises with the tail gas to the gas-solid two-phase outlet (1021) and is discharged. After gas-solid separation, the pre-reduced ore powder is injected into the main furnace reaction zone (101) through the ore material distribution device (2). At the same time, the reducing agent supply unit (3) provides high-temperature reducing gas to the main furnace reaction zone (101). The reducing gas and ore powder are fully mixed and contacted in the main furnace reaction zone (101). The reducing gas reacts with the iron oxides in the ore powder to produce water vapor and molten iron and slag. The generated iron and slag fall into the lower molten pool zone (103), where slag and iron are separated. The separated slag forms a slag layer in the upper part of the molten pool zone (103), and the iron forms a molten iron layer in the lower part of the molten pool zone (103). The slag is discharged periodically through the slag outlet (1031), and the molten iron is discharged through the iron outlet (1032).

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