Counter-current flash furnace and smelting method

Abstract

The application discloses a countercurrent flash furnace and a smelting method, and belongs to the technical field of metallurgy. The flash furnace is used for countercurrent smelting, the heat exchange and reaction efficiency of reducing gas and furnace charges are improved, and the smelting cost is reduced. In addition, the fine material injection device is arranged in the soft melting zone or the melting liquid zone of the furnace body, so that the small-particle-size furnace charges which cannot fall and react in the countercurrent mode are injected and reacted in the part and fall into the molten pool, and the problem that small-particle-size furnace charges escape and cannot be fully smelted in the countercurrent smelting process, thereby reducing the smelting efficiency, is solved.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical technology, specifically relating to a countercurrent flash furnace and a smelting method. Background Technology

[0002] Flash ironmaking is a cutting-edge technology in the metallurgical field. It involves instantly mixing extremely fine iron ore powder and reducing gas at high temperatures, completing the reduction reaction within seconds. Compared to traditional blast furnace processes, flash ironmaking offers significant advantages such as higher reaction efficiency, the ability to achieve low-carbon or even carbon-free smelting, wider raw material adaptability, and a shorter process flow.

[0003] In existing flash ironmaking technologies, reactants typically move in a "co-current" manner, where the ore powder and reducing gas move downwards in the same direction. In contrast, a "counter-current" manner (ore powder downwards, reducing gas upwards) theoretically enhances the contact between the gas and solid phases, significantly improving the efficiency of chemical and heat exchange. However, this method has a fatal flaw: the upward airflow severely entrains the falling ore powder. When the drag force on the particles exceeds their weight, they are carried away from the reaction zone by the airflow, preventing them from falling into the molten pool to complete final reduction and aggregation. This phenomenon is particularly pronounced in flash ironmaking, where the ore powder used has an extremely fine particle size, with a fine particle escape rate as high as 50%, severely limiting reaction efficiency and metal yield.

[0004] Chinese patent document CN119144784A (202410736035.5) discloses a flash reduction device and method integrating coal-to-reducing gas and flash reduction. Although this scheme uses a dust removal device to return the furnace charge in the exhaust gas to the furnace, the returned ore powder still has the problem of continued escape, causing fine ore powder to idle in the furnace and recovery device, reducing smelting efficiency and increasing energy consumption. At the same time, this scheme uses nitrogen to return the furnace charge, but nitrogen does not participate in the reaction in the furnace but absorbs heat, resulting in a waste of heat resources.

[0005] Therefore, the present invention aims to solve the key technical problem that fine-particle ore powder is easily carried away and escaped by airflow in the reverse flow field flash ironmaking process. Summary of the Invention

[0006] The purpose of this invention is to provide a countercurrent flash furnace and smelting method to improve the efficiency of flash iron / steel smelting, reduce smelting costs, and overcome the problem of fine particle escape in countercurrent smelting.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a countercurrent flash furnace, comprising a furnace body; The furnace body is a hollow, cylindrical shell with a steel plate on the outside and refractory material on the inside, and a cooling wall in the high-heat zone. The furnace body consists of, from top to bottom, an air-classified material distribution zone, a solid reduction zone, a softening reduction zone, a molten liquid zone, and a molten pool zone; The lower part of the molten pool area is a layer of molten iron, and the upper part is a layer of slag. The furnace wall corresponding to the molten iron layer is provided with an iron tapping port, and the furnace wall corresponding to the slag layer is provided with a slag tapping port. The air-separated material distribution area is equipped with a furnace gas outlet and a material distribution device; A fine material injection device is provided on the furnace side wall corresponding to the upper part of the molten liquid zone and / or the lower part of the softening reduction zone. The furnace gas outlet is connected to the fine material injection device through a gas-solid separation device. The carrier gas injected by the fine material injection device is one or a combination of reducing gas, carbon dioxide, and system tail gas. A reducing agent supply unit is provided in the lower part of the molten liquid zone and / or near the fine material injection device. This reducing agent supply unit provides the reducing gas and heat required for the reaction. As the furnace charge sequentially passes through the solid reduction zone, the softening reduction zone, and the liquid zone, it transforms from a solid state to a softening state and then to a liquid state, respectively. Preferably, the solid reduction zone, near the point where it enters the softening reduction zone, has a sudden change in the furnace shell inner diameter; the furnace diameter changes rapidly, then gradually decreases. Preferably, the maximum flow area at the abrupt change section of the furnace shell diameter is 10% to 50% larger than the cross-section of the furnace body above it. The expanded flow area section extends to the molten liquid zone. The furnace charge in the softening and reduction zone is in a softened state and has high viscosity. By setting the furnace body diameter expansion section, the rising wind speed of the fine particles injected into the furnace area is reduced, and the molten material is prevented from sticking to the furnace wall.

[0008] Preferably, the reducing agent supply unit of the present invention includes a reducing gas inlet and a gas heating unit, wherein the reducing gas inlet is disposed on the side wall of the furnace body and is connected to the gas heating unit; The gas heating unit is used to heat the reducing gas; the reducing gas is room temperature reducing gas or preheated reducing gas; Preferably, the gas heating unit is a reducing gas heater or a plasma heating device; Preferably, the reducing gas heater is a reducing gas heating chamber protruding from the furnace body. The reducing gas heating chamber is provided with a combustion chamber, a combustion nozzle is provided at one end of the reducing gas heating 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 carbon-containing fuel inlet and an oxygen-containing combustion-supporting gas inlet; At least one reducing gas inlet is provided on the combustion end and / or sidewall of the reducing gas heater; Preferably, the reducing gas introduced into the reducing gas inlet flows closely against the circumferential sidewall of the reducing gas heating chamber to form an air curtain; the fuel and combustion-supporting fuel burn in the chamber of the original gas heater to generate heat, which is used to heat the reducing gas. At the same time, the reducing gas forms an air curtain in the chamber of the original gas heater, which plays a role in cooling and protecting the inner wall of the reducing gas heater. Preferably, the reducing gas injection inlet forms an angle with the axial direction of the reducing gas heating chamber to form a spiral gas curtain. 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, which increases the travel before entering the reducing gas inlet and helps to increase the temperature of the reducing gas. Alternatively, the reducing agent supply unit may include a reducing gas inlet and a supplementary heating gas inlet disposed on the side wall of the furnace body, or may include a reducing gas inlet and a supplementary heating gas production raw material supply device disposed on the side wall of the furnace body. The reducing gas inlet is used to supply room temperature reducing gas or preheated reducing gas, and the supplementary heating gas inlet or the supplementary heating gas production raw material supply device is used to provide heat. 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.

[0009] Preferably, the inlet end of the reducing gas inlet, or the inlet end of the plasma heater or reducing gas heater connected to the reducing gas inlet, is further connected to a reducing gas supply device. Preferably, the reducing gas supply device is one or any combination of a coal gasifier or 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. The coal gasifier or coal-to-hydrogen device, the electrolytic hydrogen device, the coke oven gas-to-hydrogen device, the methanol-to-hydrogen device, and the ammonia-to-hydrogen device can employ existing technologies.

[0010] Preferably, the reducing agent supply unit of the present invention includes a composite spray gun containing carbon-containing fuel and oxygen-containing combustion-supporting gas inserted into the furnace body, which generates reducing hot flue gas through incomplete combustion in the furnace. Preferably, the composite spray gun containing carbon fuel and oxygen-containing combustion-supporting gas is connected to a fuel supply device and a combustion-supporting gas supply device; Preferably, the carbon-containing fuel is pulverized coal, natural gas or coal gas, and the oxygen-containing combustion-supporting gas is pure oxygen or oxygen-enriched gas; Preferably, when the molten iron in the furnace needs to be carburized, a composite lance containing carbon fuel and oxygen-containing combustion aid is used to inject the required excess pulverized coal to achieve this.

[0011] Preferably, the fabric feeding device is connected to the mineral drying device. Preferably, the ore drying device is a rotary kiln or a fluidized bed, which utilizes the waste heat of the system exhaust gas for drying; Preferably, the ore drying device is also connected to a crushing and grinding device.

[0012] Preferably, in this invention, the furnace gas outlet is connected to the first dust collector, and 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. 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 reducing gas heater or the plasma heater. The discharge ports of the first and second dust collectors are connected to the fine material injection device. 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 provided between the outlet of the second dust collector and the carbon dioxide removal device. The first dust collector can be a cyclone dust collector, a multi-tube dust collector, or a high-temperature ceramic dust collector, and the second dust collector can be a bag filter. In the above scheme, after the exhaust gas in the furnace passes through the dust collector outlet, it can be sent to the external supply network for continued use, or it can be converted to obtain hydrogen and returned to the furnace to continue participating in the reduction reaction.

[0013] Preferably, the furnace body is a modified blast furnace according to the present invention; The furnace chamber above the hearth of the blast furnace body serves as the air classifier and material distribution zone, the solid reduction zone, the soft melting reduction zone, and the molten liquid zone. The hearth of the blast furnace serves as the molten pool zone, which can effectively reduce the construction cost of the furnace body.

[0014] Preferably, the molten pool zone is provided with an extended section in the horizontal direction. The end of the extended section, away from the furnace body, is equipped with a supplementary heating gas inlet or a supplementary heating gas feedstock supply device. Preferably, the supplementary heating gas feedstock supply device is a composite spray gun containing carbon-containing fuel and oxygen-containing combustion-supporting fuel. An iron tapping port and a slag tapping port are provided on the furnace wall at the end of the extended section, away from the furnace body. By providing the extended section and placing the iron tapping port and slag tapping port on the extended end of the molten pool zone, the separation path between molten iron and steel slag is extended, making it suitable for smelting highly viscous iron ore. High-temperature gas is used to supplement heat to the molten pool, ensuring that the temperature of the molten iron is maintained above the preset temperature.

[0015] Preferably, the reducing agent supply unit of the present invention includes a carbon monoxide reducing gas inlet or a composite spray gun containing carbon fuel and oxygen-containing combustion gas disposed on the furnace body located in the lower part of the molten liquid zone and / or near the fine material injection device. The composite spray gun containing carbon fuel and oxygen-containing combustion gas is used to produce hot carbon monoxide gas in the furnace. The reducing agent supply unit also includes a hydrogen reducing gas inlet located at the bottom of the solid reduction zone and / or the soft melting reduction zone; A heating device is installed before the reducing gas inlet to allow high-temperature reducing gas to enter the reducing gas inlet, or a supplementary heating gas inlet or a supplementary heating gas production raw material supply device is installed near the reducing gas inlet.

[0016] Preferably, the fabric distribution device of the present invention is a multi-point fabric distribution device, comprising multiple fabric distribution units disposed in the air-separated fabric distribution area, wherein the fabric distribution units are respectively connected to the blow tank, the pressure equalization tank and the fabric distribution bin in sequence through fabric 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 blast furnace through the material distribution unit. Preferably, the furnace charge is 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.

[0017] Preferably, the fabric distribution device of the present invention is a steering wheel fabric distributor; the steering wheel type fabric distributor 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.

[0018] 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.

[0019] Preferably, the material distribution device of the present invention is a side-wind material distributor; the side-wind material distributor includes a nozzle disposed on the furnace top, the nozzle opening facing downward and 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. By rationally distributing multiple nozzles on the top of the furnace body, combined with independent material distribution air channels, a high degree of dispersion and uniform distribution of the furnace charge on the furnace cross section can be achieved, avoiding local accumulation and creating optimal initial conditions for efficient and uniform flash reaction.

[0020] Preferably, the fabric distribution device of the present invention is a U-shaped fabric distributor; the U-shaped fabric distributor includes a U-shaped tube, the end of which is bent upward to form a discharge port, and the discharge port is arranged vertically upward or inclined upward. Preferably, a ore baffle is provided on the charge injection path of the U-shaped tube outlet, and the ore baffle is fixedly installed inside the furnace body. By setting multiple distribution points evenly distributed on the cross-section of the furnace body, and combining them with a unique "upward injection" method, the charge is injected into the furnace chamber in multiple streams under the action of the carrier gas. Natural dispersion is achieved by utilizing gravity and collision, effectively overcoming the drawbacks of the traditional "central column" type of charge feeding, and realizing efficient mixing and heat exchange between the charge and the reducing gas.

[0021] By setting a baffle on the injection path at 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.

[0022] This invention also discloses a countercurrent flash smelting method, utilizing the aforementioned countercurrent flash furnace, comprising the following steps: The furnace charge enters from the solid reduction zone of the furnace body, and the reducing gas enters from the molten liquid zone or the soft melting reduction zone of the furnace body, or the reducing gas is prepared in the molten liquid zone or the soft melting reduction zone; The furnace charge moves from top to bottom. During the movement, it exchanges heat with the counter-current reducing gas. After reaching the temperature conditions, it undergoes a flash reduction reaction with the reducing gas in the gas flow. When passing through the high-temperature zone of the molten liquid zone, the iron-containing raw material particles are heated to liquid state and finally fall into the molten pool zone. The exhaust gas after the reaction is mixed with a large number of escaped fine particles from the furnace charge. It is discharged from the flue gas outlet at the top of the furnace. The escaped fine particles enter the gas-solid separation device with the exhaust gas. After being captured, they are sent back into the furnace through the fine material feeding device set in the softening reduction zone. The reduction reaction is completed quickly and the particles are liquefied. They agglomerate in the softening reduction zone and adhere to the falling large particles. Finally, they fall into the molten pool in the molten pool zone. The molten material falling into the molten pool melts under the influence of gravity, forming an iron layer and a slag layer, which are then discharged from the furnace through the tapping spout and slag outlet. The gas-solid separation device is one of the following: cyclone dust collector, multi-tube cyclone dust collector, ceramic tube dust collector, bag filter, or electrostatic precipitator.

[0023] Preferably, in this invention, pulverized coal / granular coal and oxygen-containing gas are added from the molten liquid zone or the softening reduction zone to prepare hot coal gas or hot flue gas containing CO, so as to provide heat and reducing gas.

[0024] Preferably, in this invention, the heated reducing gas enters from the molten liquid zone or the soft melting reduction zone, and / or the reducing gas and the high-temperature flue gas enter from the molten liquid zone or the soft melting reduction zone respectively and mix, with the reducing gas being heated by the high-temperature flue gas.

[0025] Preferably, the exhaust gas, which still contains a large amount of CO, is purified by a gas-solid separation device, a dehydration device, and a CO2 removal device installed outside the furnace, and then enters a catalytic conversion device to convert CO into H2, and then returns to the furnace to make full use of the exhaust gas. Alternatively, after removing carbon dioxide, carbon monoxide in the exhaust gas can be returned. The reduction potential of hydrogen to reduce iron is better than that of carbon monoxide. Preferably, the converted H2 re-enters the furnace through the reducing gas inlet located in the molten liquid zone or the reducing gas inlet of the combustion chamber connected to the molten liquid zone, mixes and exchanges heat with the hot flue gas, and moves together from bottom to top to carry out a flash reduction reaction on the mineral powder.

[0026] Preferably, before entering the furnace body, the furnace charge is classified by a particle size sorting device. Particles that escape the specified particle size are introduced into the furnace body's softening and reduction zone through a fine material injection device, while the remaining particles are introduced into the furnace body's solid reduction zone through a material distribution device, thereby reducing the amount of exhaust gas to be treated and improving the reaction efficiency.

[0027] Compared with the prior art, the beneficial effects of the present invention are: Using the flash furnace of this invention, the countercurrent smelting process improves the heat exchange and reaction efficiency between the reducing gas and the furnace charge, thereby reducing smelting costs. Furthermore, by employing a fine material injection device in the softening zone or molten liquid zone of the furnace body, smaller particle sizes that cannot be fed into the furnace in countercurrent mode are injected into this zone for reaction and fall into the molten pool. This solves the problem of low smelting efficiency caused by the escape of smaller particle sizes during countercurrent smelting, resulting in insufficient smelting. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the countercurrent flash furnace described in Example 1; Figure 2 This is a schematic diagram of the countercurrent flash furnace described in Example 2; Figure 3 This is a schematic diagram of the countercurrent flash furnace structure described in Example 3; Figure 4 A schematic diagram of the external hydrogen production structure in the tail gas recirculation furnace; Figure 5 Schematic diagram of the steering wheel fabric structure Figure 1 ; Figure 6 This is a structural diagram of the crosswind fabric structure; Figure 7 This is a structural diagram of a U-shaped material; Figure 8 Schematic diagram of the reducing gas injection inlet of the reducing gas heating chamber Figure 1 ; Figure 9 Schematic diagram of the reducing gas injection inlet of the reducing gas heating chamber Figure 2 ; Figure 10 Schematic diagram of the reducing gas injection inlet of the reducing gas heating chamber Figure 3 ; Figure 11 Schematic diagram of the steering wheel fabric structure Figure 2 ; In the diagram, 1 is the furnace body, 101 is the air-classification material distribution zone, 102 is the solid reduction zone, 103 is the softening reduction zone, 104 is the molten liquid zone, and 105 is the molten pool zone. 2. Iron tapping spout, 3. Slag tapping spout, 4. Furnace gas outlet, 5. Charging device, 6. Fine material injection device, 7. Reducing agent supply unit; 106 Abrupt change in furnace shell inner diameter; 1051 Extended section; 8 Reducing gas heater, 81 Reducing gas heating chamber, 9 Plasma heating device, 10 Combustion torch, 11 Reducing gas supply device; 12 First dust collector, 13 Heat exchanger, 14 Carbon dioxide removal unit, 15 Hydrogen conversion unit; 51 fabric unit, 16 fabric tubes, 17 fabric bins; 1000 Steering wheel material feeder, 1001 Material discharge pipe, 1002 Main air supply pipe, 1003 Air supply ring pipe, 1004 Air jet hole; 2000 Side air distributor, 2001 Nozzle, 2002 Feed channel, 2003 Distribution air channel; 3000U-type material distributor, 3001U-type pipe, 3002 aggregate baffle, 3003 pipe dredging; 18 Fuel supply unit, 19 Oxygen supply unit. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will now be clearly and completely described in conjunction with the accompanying drawings.

[0030] Example 1 like Figure 1As shown, in this embodiment, the internal space of the countercurrent flash furnace body 1 is divided from top to bottom into an air-classifying and feeding zone 101, a solid reduction zone 102, a softening and reduction zone 103, a molten liquid zone 104, and a molten pool zone 105. The bottom molten pool zone is divided into a slag layer and a molten iron layer. A slag outlet 3 is provided in the slag layer height direction, and an iron outlet 2 is provided in the molten iron layer height direction.

[0031] A reducing agent supply unit 7 is provided at the lower part of the molten liquid zone 104 and / or near the fine material injection device 6. The reducing agent supply unit is used to provide the reducing gas and heat required for the reaction.

[0032] In this embodiment, the reducing agent supply unit 7 includes a reducing gas inlet and a gas heating unit. The reducing gas inlet is located on the side wall of the furnace body 1 and is connected to the gas heating unit.

[0033] The gas heating unit is used to heat the reducing gas.

[0034] In this embodiment, the gas heating unit is a plasma heater 9.

[0035] The reducing gas inlet or the front end of the plasma heater 9 connected to the reducing gas inlet is also connected to a reducing gas supply device 11.

[0036] The reducing gas supply device 11 is one or any combination of a coal gas generator or 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.

[0037] The furnace charge enters the flash furnace through the charge inlet of the charging device 5 and moves downwards. The high-temperature reducing gas is hydrogen, which enters the furnace body through the reducing gas inlet and moves upwards. The high-temperature hydrogen moves in the opposite direction to the furnace charge, reacting and exchanging heat during the process.

[0038] Fine particles enter the furnace body through the fine material inlet of the fine material injection device 6. They rapidly react with high-temperature hydrogen in the molten liquid zone 104 or the softening and reduction zone 103, and agglomerate due to collisions with the falling furnace charge, which is already in a softened or molten state, falling together into the bottom molten pool zone 105. The exhaust gas from the reaction is discharged from the furnace body through the furnace gas outlet 4. Because this embodiment achieves the return of escaped ore powder, ensuring the utilization rate of the ore powder, the furnace body 1 in this embodiment is a vertical furnace body, which can effectively reduce the floor space and increase the temperature of the molten pool.

[0039] The fabric distribution device 5 is a multi-point fabric distribution device, which includes multiple fabric distribution units set in the air separation fabric distribution area. The fabric distribution units 51 are connected to the blow tank, the pressure equalization tank and the fabric distribution bin 17 in sequence through the fabric distribution pipe 16.

[0040] 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 blast furnace through the material distribution unit.

[0041] The furnace charge is iron ore powder, flux, or a mixture of ore powder and carbon powder or coal powder.

[0042] like Figure 5 As shown, the fabric distribution unit is a steering wheel fabric distributor 1000; the steering wheel fabric distributor includes a feed pipe 1001, a main air supply pipe 1002, and an air supply ring pipe 1003.

[0043] The feeding pipe 1001 is connected to the rear end of the material distribution pipe 16; the main air supply pipe 1002 enters the feeding pipe through the opening in the side wall of the feeding pipe 1001 and runs in the same direction as the feeding pipe; the air supply ring pipe 1003 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 1003 is horizontally arranged in the furnace body, and multiple air jet holes 1004 are opened circumferentially on the pipe wall of the air supply ring pipe 1003.

[0044] The jet nozzle 1004 can be disposed on the outer ring side wall of the air supply ring pipe 1003 or on the inner ring side wall of the air supply ring pipe 1003. The jet nozzle 1004 is disposed radially through the wall of the air supply ring pipe 1003 to provide lateral dispersing force for the furnace charge, thereby achieving the effect of dispersed material distribution.

[0045] To improve the uniformity of air distribution, multiple layers of annularly distributed jet holes 1004 can be provided on the air supply ring pipe 1003.

[0046] To improve fabric uniformity, in this embodiment, the air jet holes 1004 are evenly distributed in a ring along the circumference of the air supply ring pipe 1003.

[0047] Example 2 like Figure 2 As shown, the difference between this embodiment and Embodiment 1 is that this embodiment includes a reducing gas heating chamber 81 as a reducing gas heater. Powdered coal and oxygen are introduced into the reducing gas heating chamber 81 for complete combustion to generate a high-temperature heat source. The reducing gas heater 81 is a reducing gas heating chamber 81 protruding from the furnace body 1. The reducing gas heating chamber 81 has a combustion chamber, a combustion nozzle 10 at one end along the axial direction of the reducing gas heating chamber 81, and a reducing gas outlet at the other end, which is connected to the reducing gas inlet on the side wall of the furnace body. The reducing gas heating chamber 81 consists of a steel plate outer shell, an inner refractory lining, and water-cooled walls where necessary.

[0048] The combustion nozzle 10 is equipped with a carbon-containing fuel inlet and an oxygen-containing combustion-supporting gas inlet. The carbon-containing fuel inlet and the oxygen-containing combustion-supporting gas inlet are respectively connected to the fuel supply device 18 and the oxygen supply device 19.

[0049] Carbon-containing fuels are pulverized coal, coal gas, or natural gas, while oxygen-containing combustion-supporting fuels are pure oxygen or oxygen-enriched gas.

[0050] like Figures 8-10 As shown, at least one reducing gas injection inlet is provided on 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.

[0051] Specifically, such as Figure 8 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.

[0052] like Figure 9 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.

[0053] like Figure 10 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.

[0054] Part of the hydrogen enters through the reducing gas heating chamber 81, serving as the cooling gas for the chamber. The remaining hydrogen enters through the reducing gas inlet 71, which is located near the inlet of the reducing gas heating chamber 81. After the room-temperature hydrogen comes into contact with the high-temperature heat source and heats up, it reacts with the furnace charge.

[0055] The molten pool zone 105 is provided with an extended section 1051 in the horizontal direction. The end of the extended section 1051 away from the main body of the furnace body 1 is provided with a supplementary heating gas inlet. An iron tapping port and a slag tapping port are provided on the furnace wall at the end of the extended section away from the furnace body 1.

[0056] like Figure 6 As shown, the material distribution unit 51 is a side air material distributor 2000; the side air material distributor 2000 includes a nozzle 2001 disposed on the furnace top, the nozzle opening facing downward and inclined.

[0057] A feeding channel 2002 is provided above the nozzle, and the feeding channel 2002 is connected to the material distribution pipe 16.

[0058] The nozzle sidewall is provided with a fabric air channel 2003, and the outlet of the fabric air channel is inclined toward the nozzle opening. The fabric air channel 2003 is connected to the fabric air system.

[0059] Example 3 like Figure 3 As shown, the difference between this embodiment and embodiment 2 is that a sudden change section of the inner diameter of the furnace shell is provided on the furnace body 1, a first dust collector 12 and a hydrogen conversion device 15 are connected to the rear end of the furnace gas outlet 4, and the pulverized coal introduced into the combustion chamber is incompletely combusted with oxygen to generate carbon monoxide and a small amount of hydrogen as the reaction gas in the furnace.

[0060] On the furnace body 1, at the height of the softening reduction zone 103 and the molten liquid zone 104, a sudden change section 106 of the furnace shell inner diameter is provided. The diameter of the sudden change section is larger than the furnace body diameter of the upper solid reduction zone 102. The flow cross-sectional area of ​​the sudden change section 106 is 10% to 50% larger than the cross-section of the furnace body 6 above and below it, and the expanded flow area extends to the molten liquid zone 104. After the furnace charge reaches the softening reduction zone 103, it softens due to the temperature rise and easily adheres to the furnace wall. The diameter expansion structure can effectively prevent the furnace charge from sticking in this part. At the same time, fine particles of furnace charge are easily carried upward by the airflow after entering. After the diameter expansion structure is provided on the furnace body, the wind speed at this height of the furnace body 1 will be reduced, which can reduce the escape of fine particles.

[0061] like Figure 4 As shown, a first dust collector 12 is installed at the furnace gas outlet 4 to collect fine particles in the exhaust gas, and these fine particles are then injected back into the furnace for reaction through a conveying device and a fine material injection device 6.

[0062] The air outlet of the first dust collector 12 is connected to the hot side inlet of the heat exchange device 13.

[0063] The hot-side outlet of the heat exchange device 13 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 (not shown in the figure), and the other outlet is connected to the carbon dioxide removal device 14 and the dehydration device (not shown in the figure) in sequence. The outlet of the dehydration device is connected to the inlet of the circulating fan (not shown in the figure). The outlet of the circulating fan is connected to the cold-side inlet of the heat exchange device 13. The cold-side outlet of the heat exchange device 13 is connected to the inlet of the reducing gas heater 8 or the plasma heater 9 (not shown in the figure).

[0064] The discharge port of the first dust collector 12 and the discharge port of the second dust collector are connected to the fine material injection device 6.

[0065] A sulfur dioxide removal device (not shown in the figure) is installed between the hot side outlet of the heat exchange device 13 and the second dust collector.

[0066] A hydrogen conversion device 15 is installed between the outlet of the second dust collector and the carbon dioxide removal device 14 to convert carbon monoxide in the exhaust gas into hydrogen. After the carbon dioxide is removed by the carbon dioxide removal device 14, the hydrogen is injected back into the furnace.

[0067] like Figure 7 As shown, the fabric unit 51 is a U-shaped fabric feeder 3000; the U-shaped fabric feeder 3000 includes a U-shaped tube 3001, the end of which is bent upward to form a discharge port, and the discharge port is set vertically upward or inclined upward.

[0068] A ore baffle 3002 is installed on the charge spray path of the U-shaped tube 3001 outlet. The ore baffle 3002 is adjustable up and down to control the area of ​​ore powder spraying.

[0069] To prevent blockage of individual U-tubes 3001, two purging air inlets are installed on each U-tube 3001. These inlets connect to purging pipes 3003, through which purging air is introduced. This purging air can be used as auxiliary gas supply during normal production, or for immediate purging and unblocking when a blockage is detected. Flow and pressure gauges are installed on the purging air pipes for real-time monitoring and location of blocked sections.

[0070] 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.

[0071] Example 4 like Figure 11 As shown, the difference from Embodiment 1 is that the air supply main pipe 1002 is located outside the discharge pipe 1001 and runs downward together with the discharge pipe.

Claims

1. A countercurrent flash furnace, characterized in that: Including the furnace body (1); The furnace body (1) consists of, from top to bottom, an air-selection material distribution zone (101), a solid reduction zone (102), a soft melting reduction zone (103), a molten liquid zone (104), and a molten pool zone (105). The lower part of the molten pool zone (105) is a molten iron layer and the upper part is a slag layer. The furnace wall corresponding to the molten iron layer is provided with an iron tapping port (2) and the furnace wall corresponding to the slag layer is provided with a slag tapping port (3). The air-separated fabric distribution area (101) is equipped with a furnace gas outlet (4) and a fabric distribution device (5); Fine material injection device (6) is provided on the furnace side wall corresponding to the upper part of the molten liquid zone (104) and / or the lower part of the soft melting reduction zone (103). The carrier gas injected by the fine material injection device (6) is one or a combination of reducing gas, carbon dioxide, and system tail gas. A reducing agent supply unit (7) is provided near the molten liquid zone (104) and / or the fine material injection device (6), the reducing agent supply unit being used to provide the reducing gas and heat required for the reaction.

2. The countercurrent flash furnace as described in claim 1, characterized in that: The solid reduction zone (102) is located near the soft melting reduction zone (103) and has a sudden change section (106) in the inner diameter of the furnace shell. Preferably, the maximum flow area at the abrupt change section (106) of the furnace shell is 10% to 50% larger than the cross-section of the furnace body (1) above it, and the flow area expansion section extends to the molten liquid zone (104).

3. The countercurrent flash furnace as described in claim 1, characterized in that: The reducing agent supply unit (7) includes a reducing gas inlet and a gas heating unit. The reducing gas inlet is located on the side wall of the furnace body (1) and is connected to the gas heating unit. The gas heating unit is used to heat the reducing gas; Preferably, the gas heating unit is a reducing gas heater (8) or a plasma heater (9). Preferably, the reducing gas heater (8) is a reducing gas heating chamber (81) protruding on the furnace body (1). The reducing gas heating chamber (81) is provided with a combustion chamber. A combustion nozzle (10) is provided at one end of the reducing gas heating 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 (10) is equipped with a carbon fuel inlet and an oxygen-assisted combustion inlet; At least one reducing gas inlet is provided on the combustion end and / or side wall of the reducing gas heater (8); Preferably, the reducing gas supplied by the reducing gas injection inlet flows closely against the circumferential sidewall of the reducing gas heating chamber (81) to form an air curtain; Preferably, the reducing gas inlet forms an angle with the axial direction of the reducing gas heating chamber (81) to form a spiral gas curtain; The reducing agent supply unit (7) may include a reducing gas inlet and a supplementary heating gas inlet on the side wall of the furnace body (1), or may include a reducing gas inlet and a supplementary heating gas raw material supply device on the side wall of the furnace body (1). The reducing gas inlet is used to supply room temperature reducing gas or preheated reducing gas, and the supplementary heating gas inlet or supplementary heating gas raw material supply device is used to provide heat. 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.

4. The countercurrent flash furnace as described in claim 3, characterized in that: The inlet end of the reducing gas inlet, or the inlet end of the plasma heater (9) or reducing gas heater (8) connected to the reducing gas inlet, is also connected to a reducing gas supply device (11). Preferably, the reducing gas supply device (11) is one or any combination of a coal gas generator or 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.

5. The countercurrent flash furnace as described in claim 1, characterized in that: The reducing agent supply unit (7) includes a composite spray gun containing carbon fuel and oxygen-containing combustion aid inserted into the furnace body (1), which generates reducing hot flue gas through incomplete combustion in the furnace. Preferably, the composite spray gun containing carbon fuel and oxygen-containing combustion-supporting gas is connected to a fuel supply device and a combustion-supporting gas supply device; Preferably, the carbon-containing fuel is pulverized coal, natural gas or coal gas, and the oxygen-containing combustion-supporting gas is pure oxygen or oxygen-enriched gas; Preferably, when the molten iron in the furnace needs to be carburized, a composite lance containing carbon fuel and oxygen-containing combustion aid is used to inject the required excess pulverized coal to achieve this.

6. The countercurrent flash furnace as described in claim 1, characterized in that: The fabric feeding device (5) is connected to the ore drying device; Preferably, the ore drying device is a rotary kiln or a fluidized bed, and the ore drying device is connected to the furnace gas outlet (4) to use the waste heat of the system tail gas for drying; Preferably, the ore drying device is also connected to a crushing and grinding device.

7. The countercurrent flash furnace as described in claim 1, characterized in that: The furnace gas outlet (4) is connected to the first dust collector (12), and the air outlet of the first dust collector (12) is connected to the hot side inlet of the heat exchange device (13). The heat exchange device (13) 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 (14) 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 (13). The cold side outlet of the heat exchange device (13) is connected to the inlet of the reducing gas heater (8) or the plasma heater (9). The discharge port of the first dust collector (12) and the discharge port of the second dust collector are connected to the fine material injection device (6); Preferably, a sulfur dioxide removal device is provided between the hot side outlet of the heat exchange device (13) and the second dust collector; Preferably, a hydrogen conversion device (15) is provided between the outlet of the second dust collector and the carbon dioxide removal device (14).

8. The countercurrent flash furnace as described in claim 1, characterized in that: The furnace body (1) was modified from a blast furnace; The blast furnace body above the hearth serves as the air classifier charging zone (101), solid reduction zone (102), softening reduction zone (103), and molten liquid zone (104), while the blast furnace hearth serves as the molten pool zone (105).

9. The countercurrent flash furnace as described in claim 1, characterized in that: The molten pool area (105) is provided with an extended section (1051) in the horizontal direction. The end of the extended section (1051) away from the furnace body (1) is provided with a supplementary heating gas inlet or a supplementary heating gas production raw material supply device. An iron tapping port and a slag tapping port are provided on the furnace wall at the end of the extended section away from the furnace body (1).

10. The countercurrent flash furnace as described in claim 1, characterized in that: The reducing agent supply unit (7) includes a carbon monoxide reducing gas inlet or a composite spray gun containing carbon fuel and oxygen-containing combustion gas on the furnace body (1) located at the lower part of the molten liquid zone (104) and / or near the fine material injection device (6). The composite spray gun containing carbon fuel and oxygen-containing combustion gas is used to produce hot carbon monoxide gas in the furnace. The reducing agent supply unit (7) further includes a hydrogen reducing gas inlet located at the bottom of the solid reduction zone (102) and / or the soft melting reduction zone (103); A heating device is installed before the reducing gas inlet to allow high-temperature reducing gas to enter the reducing gas inlet, or a supplementary heating gas inlet or a supplementary heating gas production raw material supply device is installed near the reducing gas inlet.

11. The countercurrent flash furnace as described in any one of claims 1-10, characterized in that: The fabric distribution device (5) is a multi-point fabric distribution device, including multiple fabric distribution units (51) set in the air-separated fabric distribution area (101). The fabric distribution units are connected to the blow tank, the pressure equalization tank and the fabric distribution bin (17) in sequence through the fabric distribution pipe (16). The injection tank and / or the feeding pipe (16) are provided with a carrier gas inlet to inject the furnace charge into the flash blast furnace through the feeding 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 (51) are evenly arranged within the cross-section of the furnace body.

12. The countercurrent flash furnace as described in claim 11, characterized in that: The fabric distribution unit (51) is a steering wheel fabric distributor (1000); the steering wheel fabric distributor (100) includes a feed pipe (1001), a main air supply pipe (1002), and an air supply ring pipe (1003). The feed pipe (1001) is connected to the rear end of the fabric distribution pipe (16); the air supply main pipe (1002) enters the feed pipe through the opening in the side wall of the feed pipe (1001) and runs in the same direction as the feed pipe, or the air supply main pipe (1002) is located outside the feed pipe (1001) and runs downward together with the feed pipe; the air supply ring pipe (1003) is located at the end of the air supply main pipe (1002) and in the lower space of the feed pipe (1001), and multiple air jet holes (1004) are opened circumferentially on the pipe wall of the air supply ring pipe (1003).

13. The countercurrent flash furnace as described in claim 11, characterized in that: The material distribution unit (51) is a side air distributor (200); the side air distributor (2000) includes a nozzle (2001) disposed on the top of the furnace body (1), the nozzle (2001) opening downward and being inclined; A feeding channel (2002) is provided above the nozzle (2001), and the feeding channel (2002) is connected to the material distribution pipe (16); The nozzle (2001) has a fabric air channel (2003) on its side wall, and the outlet of the fabric air channel (2003) is inclined toward the opening of the nozzle (2001).

14. The countercurrent flash furnace as described in claim 11, characterized in that: The fabric unit (51) is a U-shaped fabric feeder (3000); the U-shaped fabric feeder (3000) includes a U-shaped tube (3001), the end of the U-shaped tube (3001) is bent upward to form a discharge port, and the discharge port is set vertically upward or inclined upward. Preferably, a ore baffle (3002) is provided on the furnace charge injection path of the U-shaped tube (3001) outlet, and the ore baffle (3002) is fixedly installed inside the furnace body (1).

15. A countercurrent flash smelting method, utilizing the countercurrent flash furnace according to any one of claims 1 to 14, characterized in that, Includes the following steps: The furnace charge enters from the solid reduction zone (102) of the furnace body, and the reducing gas enters from the molten liquid zone (104) or the soft melting reduction zone (103) of the furnace body, or the reducing gas is prepared in the molten liquid zone (104) or the soft melting reduction zone (103); The furnace charge moves from top to bottom. During the movement, it exchanges heat with the counter-current reducing gas. After reaching the temperature conditions, it undergoes a flash reduction reaction with the reducing gas in the gas flow. When passing through the molten liquid zone (104) and the high temperature zone, the iron-containing raw material particles are heated to liquid and finally fall into the molten pool zone (105). The exhaust gas after the reaction is mixed with a large number of escaped fine particles from the furnace charge. It is discharged from the flue gas outlet (4) at the top of the furnace body. The escaped fine particles enter the gas-solid separation device with the exhaust gas. After being captured, they are sent back into the furnace through the fine material feeding device (6) set in the softening reduction zone (103) or the molten liquid zone (104). The reduction reaction is completed quickly and the particles are liquefied. They agglomerate in the softening reduction zone (103) and adhere to the falling large particles. Finally, they fall into the molten pool in the molten pool zone (105). The liquid material falling into the molten pool melts and separates under the action of gravity, forming an iron layer and a slag layer, which are then discharged from the furnace through the tapping port (2) and the slag tapping port (3).

16. The countercurrent flash smelting method as described in claim 15, characterized in that: Powdered coal / granular coal and oxygen-containing gas are added from the molten liquid zone (104) or the softening reduction zone (103) to prepare hot coal gas or hot flue gas containing CO components for heating and providing reducing gas.

17. The countercurrent flash smelting method as described in claim 15, characterized in that: The heated reducing gas enters from the molten liquid zone (104) or the soft melting reduction zone (103), and / or the reducing gas and the high-temperature flue gas enter from the molten liquid zone (104) or the soft melting reduction zone (103) respectively and mix, and the reducing gas is heated by the high-temperature flue gas.

18. The countercurrent flash smelting method as described in claim 15, characterized in that: The exhaust gas, which still contains a large amount of CO, is purified by a gas-solid separation device, a dehydration device, and a CO2 removal device installed outside the furnace. Then it enters the catalytic converter to convert CO into H2 and is returned to the furnace. Preferably, the converted H2 enters the furnace again through the reducing gas inlet in the molten liquid zone (104) or the reducing gas inlet in the combustion chamber connected to the molten liquid zone (104), mixes and exchanges heat with the hot flue gas, and moves together from bottom to top to carry out a flash reduction reaction on the mineral powder.

19. The countercurrent flash smelting method as described in claim 15, characterized in that: Before entering the furnace body, the furnace charge is classified by a particle size sorting device. Particles that escape the specified particle size enter the furnace body softening and reduction zone (103) through a fine material injection device (6), while the remaining particles enter the furnace body solid reduction zone through a material distribution device (5).

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