An iron ore powder reduction device and method

Abstract

The present invention belongs to the technical field of iron and steel smelting reduction equipment, and relates to an iron ore powder reduction device and method. The upper reduction bin, the middle transition bin, the lower reduction bin and the air inlet bin are sequentially connected to each other and are hermetically connected to each other. The upper reduction bin and the lower reduction bin are connected by a material conveying pipe to form a mutually connected and sealed reduction environment. The air inlet system is used to provide a reduction gas with sensible heat, which is used as the heat source for the solid-solid reduction reaction and the heat source and fluidized reduction gas for the gas-solid reduction reaction in sequence, achieving the purpose of directly reducing iron ore powder by using both the reduction gas and the solid reducing agent at the same time. Since there is no need to sinter iron ore and hydrogen and / or coal gas and coal can be directly used for the reduction of iron ore powder, energy consumption and carbon emissions are reduced throughout the process, the requirements for the gas volume, temperature and quality of the reduction gas are lowered, and it is applicable to the reduction of iron ore in the transitional stage with limited hydrogen production capacity during the development towards pure hydrogen smelting.

Description

Technical Field

[0001] The present invention belongs to the technical field of iron and steel smelting reduction equipment. Specifically, the present invention relates to an iron ore powder reduction device and method. Background Art

[0002] At present, blast furnace ironmaking is the main process for producing hot metal. This process uses agglomerated sinter and pellet as the main raw materials, and coke and pulverized coal as the main fuels. Due to the irreplaceable framework role of coke in the blast furnace, the CO2 emissions during blast furnace ironmaking account for about 70% of the total CO2 emissions in the entire iron and steel industry, making it a major carbon emission industry. To achieve carbon reduction at the source in the iron and steel metallurgy industry, it is urgent to develop new green and low-carbon metallurgy technologies. Hydrogen is an excellent reducing agent and clean energy. Exploring and developing a direct reduction ironmaking process using hydrogen instead of carbon as a reducing agent can reduce carbon dioxide emissions during ironmaking from the source, which is in line with the development trend of green, low-carbon, and clean production in the iron and steel industry.

[0003] According to the different types of reactors, the direct reduction ironmaking process is mainly divided into the rotary kiln process, the shaft furnace process, and the fluidized bed process. The rotary kiln process is mainly based on solid-solid reduction and can use solid reducing agents. However, due to the very weak gas-solid reaction, it cannot adapt to the hydrogen metallurgy process with gas-solid reactions. On the contrary, the shaft furnace process only adapts to gas-solid reactions and can adapt to the hydrogen metallurgy process, but it cannot use solid reducing agents and has the disadvantages of requiring pellet granulation and being unable to directly reduce iron ore powder. The fluidized bed direct reduction process can also adapt to the hydrogen metallurgy process and has the advantages of directly using fine ore, without the need for sintering or pelletizing processes, high mass transfer, heat transfer, and reduction efficiency, but it also cannot use solid reducing agents.

[0004] Since the increasing production capacity of green hydrogen is a gradual process, it will take more than 20 years of transition period to transition from the solid-solid reaction with solid fuel plus gas-solid reaction to the gas-solid reaction stage mainly using green hydrogen. During the transition period, there is a need for a process and device that can not only adapt to the increasing use of green hydrogen but also use carbon-containing solid reducing agents such as coal and / or coke without limitation to directly reduce iron ore powder. Summary of the Invention

[0005] The object of the present invention is to solve the above problems, and a reduction device and method for iron ore powder are provided. In the present invention, the upper reduction bin, the middle transition bin, the lower reduction bin and the air inlet bin are connected to each other in sequence and are sealed and communicated with each other. The material conveying pipe passes through the middle transition bin from the upper reduction bin and is connected to the feeding port of the lower reduction bin. The reduction gas is provided by the air inlet system as the heat source of the lower reduction bin and the heat source and fluidizing reduction gas of the upper reduction bin. At the same time, solid reducing agent is added to the lower reduction bin through the transition bin, achieving the purpose of reducing iron ore powder by using reduction gas and solid reducing agent simultaneously. And there is no rigid constraint on the proportion of green hydrogen and solid reducing agent in the reducing agent, which can adapt to the metallurgical external conditions process with the increasing proportion of green hydrogen during the transition period.

[0006] The technical problems to be solved by the present invention are achieved by the following technical solutions: A reduction device for iron ore powder, comprising an upper reduction bin (1), a middle transition bin (2), a lower reduction bin (3), an air inlet bin (4), a material conveying pipe (5), an air inlet system, an air outlet system, a discharging system and a feeding system;

[0007] The upper reduction bin (1), the middle transition bin (2), the lower reduction bin (3) and the air inlet bin (4) are connected to each other in sequence and are sealed and communicated with each other;

[0008] The upper reduction bin, the middle transition bin and the air inlet bin are all fixedly arranged. The upper reduction bin is located above the middle transition bin. The lower reduction bin is cylindrical and rotatable, and is respectively sealed and communicated with the middle transition bin and the air inlet bin at both ends. The lower reduction bin is inclined at a certain angle with the horizontal. A wind distribution plate is arranged between the upper reduction bin and the middle transition bin. Both ends of the material conveying pipe are connected to the upper reduction bin and the lower reduction bin respectively;

[0009] The upper reduction bin is provided with an air outlet and a feeding port. The air inlet bin is provided with an air inlet and a discharging port;

[0010] The air inlet system is connected to the air inlet for providing reduction gas;

[0011] The discharging system is connected to the discharging port, and the air outlet system is connected to the air outlet;

[0012] The feeding system is connected to the feeding port. The feeding system may include a first bin for providing solid materials including iron ore powder.

[0013] The upper reduction bin can be used for drying materials, heating materials, and gas-solid reduction reactions. Since a wind distribution plate is arranged below the upper reduction bin, the iron ore powder in the upper reduction bin is fluidized and reduced and heated by using the burner or supplementary gas that may exist in the middle transition bin, or directly using the reduction gas with residual heat discharged from the lower reduction bin.

[0014] The lower reduction bin can be used for solid-solid reduction reactions. Since the lower reduction bin is cylindrical and is inclined, and the two ends of the lower reduction bin are rotatably arranged on the middle transition bin and the air inlet bin, the lower reduction bin can be used to carry out solid-solid reduction reactions on iron ore powder and the operation and transportation of materials, and at the same time, it also has a certain gas-solid reaction. If the gas source temperature is relatively high or a combustion device is arranged in the lower reduction bin, it can also play a role in continuously heating the materials and accelerating the reduction reaction.

[0015] The lower reduction bin is inclined at a certain angle to the horizontal, and this angle is 0.5 - 5 degrees; since the end of the lower reduction bin connected to the middle transition bin is higher than the end connected to the air inlet bin, during the rotation of the lower reduction bin, solid-solid reduction reactions and the operation of materials are realized without additional power transmission.

[0016] Preferably, the present invention uses an externally supplied high-temperature reduction gas as a heat source to cause a carbon-based solid-solid reduction reaction between a carbon-containing material such as coal or coke particles and iron ore powder in the lower reduction bin to generate reduction gas and supplement the reduction gas for the gas-solid reduction reaction. Moreover, the heating effect on various parts inside the lower reduction bin is more uniform. Therefore, a combustion device may not be arranged at the low-end inlet of the lower reduction bin, avoiding the formation of a ring on the inner wall of the lower reduction bin caused by the locally excessive temperature conditions formed by the flame. The high-temperature reduction gas after passing through the lower reduction bin is used to preheat and carry out a reduction reaction on iron ore powder in the upper reduction bin, enabling the iron ore powder entering the lower reduction bin to immediately carry out a carbon-based solid-solid reduction reaction, improving the equipment utilization rate and reaction efficiency, and reducing investment. And in the upper reduction bin stage, the fine particles in the iron ore powder are pre-reduced in advance and are carried out of the reduction system by the high-speed gas flow, reducing the power consumption for subsequent material transportation and greatly alleviating the problem of direct reduction iron caking in the lower reduction bin.

[0017] Preferably, the present invention further includes a partition plate and a first dust removal device.

[0018] The partition plate is arranged in the middle transition bin and is located above the high-end opening of the lower reduction bin (such as Figure 2), the middle transition bin is divided into a first transition bin and a second transition bin arranged up and down, and the first transition bin and the second transition bin are interconnected through a first dust removal device. When the high-temperature reducing gas passes through the lower reduction bin, it will carry some fine solid particles, which are easy to block the air distribution plate and affect the preheating and reduction of the upper reduction bin. Therefore, a partition is arranged in the middle transition bin, and the partition is arranged above the high-end opening of the lower reduction bin, and the middle transition bin is divided into a first transition bin and a second transition bin arranged up and down, and the first transition bin and the second transition bin are interconnected through a first dust removal device, so that the solid particles in the gas are separated and discharged or partially / completely returned to the reduction system. That is, the discharged particles can be directly discharged from the current process system and used in the next process; they can also return to the upper reduction bin or the lower reduction bin. This avoids clogging and wear of the air distribution plate.

[0019] Preferably, the present invention further includes a throttle valve and an air supply pipe; a throttle valve is provided between the air intake system and the air inlet, and the air intake system is connected to the middle transition chamber through the air supply pipe.

[0020] When the amount of gas discharged from the lower reduction bin is insufficient, or the temperature of the gas discharged from the lower reduction bin is too low, which is not conducive to the preheating and reduction reaction of the upper reduction bin in the next step, a branch can be drawn from the gas source of the air intake system as a gas supply pipeline to supply high-temperature reducing gas to the upper reduction bin. If the gas source temperature is insufficient, a heating device can be installed on the gas supply pipe, or oxygen-containing gas can be introduced for combustion heating. Since the upper reduction bin requires sufficient gas volume to ensure a high flow rate for fluidization, the internal flow area of ​​the lower reduction bin is much larger than the flow area of ​​the gas supply pipe. In a parallel relationship, a large amount of air flows through the lower reduction bin, and a small amount flows through the gas supply pipe. In order to ensure that the subsequent upper reduction bin has sufficient working gas volume, the wind speed in the lower reduction bin must be very high, which will lead to the following problems: 1. The excessive wind speed in the lower reduction bin causes poor material flow, and the material may be driven by the wind to move in reverse; 2. The concentration of particles in the gas leaving the lower reduction bin increases and the particles are large, which can easily block the wind cap on the air distribution plate, at least seriously increase the wear on it, greatly reduce its service life, and bring risks to production. Therefore, when setting up the air supply pipeline, a throttle valve needs to be set on the air intake pipeline of the lower reduction bin to control the gas flow entering the lower reduction bin.

[0021] Preferably, in the present invention, the high end opening of the lower reduction bin is provided with an independent coal feeding pipeline; and the feeding system comprises a second silo connected to the coal feeding pipeline.

[0022] By setting up an independent second silo for the lower reduction bin, it is ensured that carbon-containing materials, such as coal and / or coke, react only in the lower reduction bin and do not pass through the upper reduction bin. The advantage of this is that it prevents coal from entering the lower reduction bin from the upper reduction bin. The gaseous reducing agent decomposed by the coal in the upper reduction bin has a short contact distance with the mineral powder, and the utilization efficiency is low, resulting in energy waste.

[0023] Preferably, in the present invention, the material conveying pipe sequentially passes through the air distribution plate, the middle transition bin and is connected to the high-end opening of the lower reduction bin, so that the material conveying pipe is always in a high-temperature atmosphere, which can further reduce the heat loss of the solid material during the conveying process, thereby reducing the energy consumption.

[0024] In the present invention, a burner can be arranged in the middle transition bin to solve the problem that the temperature of the flue gas is too low after passing through the lower reduction bin, affecting the preheating and reduction effects of the upper reduction bin.

[0025] Preferably, in the present invention, the air distribution plate is provided with a water cooling device, and the water cooling device is used to cool the air distribution plate by water to extend the service life of the air distribution plate.

[0026] When a burner is equipped on the upper part of the middle transition bin, the material conveying pipe can also extend out of the upper reduction bin, and the material conveying pipe (5) is arranged outside the upper reduction bin (1) and the middle transition bin (2); it enters the middle transition bin after entering from the joint of the middle transition bin and the lower reduction bin and then enters the lower reduction bin to avoid the high-temperature combustion area.

[0027] Preferably, in the present invention, the gas outlet system includes a second dust removal device. The second dust removal device is used for gas-solid separation of the gas discharged from the gas outlet of the upper reduction bin. While realizing dust removal, the separated fine particles can be partially / fully discharged from this process system and enter the next process, or can be partially / fully returned to the upper reduction bin to continue reduction. The second dust removal device (12) can also be arranged in the cavity of the upper reduction bin.

[0028] Preferably, in the present invention, a combustion device is arranged at the low-end opening of the lower reduction bin. When the temperature of the reduction gas provided by the intake gas system in the present invention is relatively low, that is, the sensible heat is insufficient, a combustion device can be arranged at the low-end opening of the lower reduction bin to heat the high-temperature reduction gas and supplement heat for the lower reduction bin.

[0029] Preferably, in the present invention, the solid material in the second bin at least contains carbon-containing materials, and the carbon-containing materials can be one or several of coal, coke particles and / or coke powder.

[0030] The present invention also discloses a method for reducing iron ore powder, which adopts the above-mentioned iron ore powder reduction device, and includes the following steps:

[0031] The high-temperature reduction gas enters the intake bin from the intake port, then sequentially passes through the lower reduction bin, the middle transition bin and the upper reduction bin, and finally is discharged from the outlet;

[0032] Iron ore powder enters the upper reduction bin from the feed inlet, where a physical and chemical process of heating and / or gas-solid reduction reaction is carried out. Then it enters the lower reduction bin through the material conveying pipe, where solid-solid reduction reaction and limited gas-solid reduction reaction occur. Finally, it is discharged from the discharge outlet to complete the production of reduced iron products with a preset reduction degree.

[0033] The dust removal equipment in the present invention can be a cyclone dust collector, a multi-tube cyclone dust collector, an electrostatic dust collector, a bag dust collector or any combination thereof.

[0034] Preferably, the reducing gas in the present invention is a high-temperature reducing gas, including H2 and / or CO.

[0035] Alternatively, when the reducing gas enters the lower reduction bin and / or the middle transition bin, a part of it is burned to supply heat for the subsequent process.

[0036] The inventive concept of the present invention:

[0037] By connecting the upper reduction bin, the middle transition bin, the lower reduction bin and the air inlet bin in sequence and sealing them to communicate with each other, a air distribution plate is arranged between the upper reduction bin and the middle transition bin, and the upper reduction bin and the lower reduction bin are connected by a material conveying pipe, so as to form a mutually connected and sealed reduction environment. The inlet system is used to provide the reducing gas, which is used as the heat source and / or reducing agent for the solid-solid reduction reaction, and the heat source and fluidizing reducing gas for the gas-solid reduction reaction in sequence, so as to achieve the purpose of reducing iron ore powder by using both reducing gas and solid reducing agent, reduce the requirements for the gas volume and quality of the reducing gas, and is especially applicable to the environmental conditions with insufficient hydrogen production capacity.

[0038] Preferably, a high-temperature reducing gas is used. When the high-temperature reducing gas passes through the lower reduction bin, it directly heats the materials in the lower reduction bin. At the same time, since reducing gas is generated during the carbon-based solid-solid reduction reaction process in the lower reduction bin, it helps to increase the content and pressure of the reducing gas in the high-temperature reducing gas, which is conducive to further improving the efficiency of the gas-solid reduction reaction of the high-temperature reducing gas in the upper reduction bin or reducing the requirements for the quality of the initial high-temperature reducing gas. After the iron ore powder enters from the feed inlet of the upper reduction bin, by utilizing the characteristics of the air distribution plate to fluidize the materials and achieve rapid heat exchange, the iron ore powder can be efficiently preheated and preliminarily reduced. After the iron ore powder enters the lower reduction bin, it directly undergoes a reduction reaction in the high-temperature reducing atmosphere created by the high-temperature reducing gas, which helps to shorten the reduction reaction time in the lower reduction bin. And in the upper reduction bin, the fine particles in the iron ore powder are carried out by the high-speed air flow, preventing the too small iron ore powder particles from entering the lower reduction bin and causing caking, which affects the production of the lower reduction bin. It solves the problem of insufficient green hydrogen production capacity during the transitional period to hydrogen metallurgy, and can directly utilize coal without using metallurgical coke, directly use iron ore powder for smelting without sintering and pelletizing, and carry out reduction reactions, achieving the purpose of reducing carbon emissions, reducing production costs, and significantly improving the environmental protection quality in the most economically feasible way under the condition of insufficient hydrogen production capacity.

[0039] In addition, by utilizing the characteristics of high heat exchange efficiency and high reaction efficiency of gas-solid reduction, the present invention preheats and partially reduces the iron ore powder, creating conditions for the subsequent reduction of the iron ore powder in the lower reduction bin, and making up for the disadvantages of low solid-solid reduction reaction efficiency and low heat exchange efficiency.

[0040] The present invention combines the upper reduction bin, the middle transition bin, the lower reduction bin, and the air inlet bin. The middle transition bin serves as both the gas outlet chamber of the lower reduction bin and the air distribution chamber of the upper reduction bin at the same time, making the whole device more compact, reducing the floor area of the factory, and reducing the heat loss during pipeline transportation, further reducing energy consumption. Since the upper reduction bin is located above the lower reduction bin, under the action of gravity, through the material conveying pipe, the solid materials can be directly discharged into the lower reduction bin without a power conveying device, which helps to reduce equipment costs and equipment energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic structural diagram of the iron ore powder reduction device described in Embodiment 1 of the present invention;

[0042] Figure 2 It is a schematic structural diagram of the iron ore powder reduction device described in Embodiment 2 of the present invention;

[0043] Figure 3 It is a schematic structural diagram of the iron ore powder reduction device described in Embodiment 3 of the present invention;

[0044] Figure 4 It is a schematic structural diagram of the iron ore powder reduction device described in Embodiment 4 of the present invention;

[0045] Figure 5 It is a schematic structural diagram of the iron ore powder reduction device described in Embodiment 5 of the present invention;

[0046] In the figure, 1 is the upper reduction bin, 101 is the air outlet, 102 is the feed inlet; 2 is the middle transition bin, 21 is the first transition bin, 22 is the second transition bin; 3 is the lower reduction bin, 31 is the coal inlet pipe; 4 is the air inlet bin, 401 is the air inlet, 402 is the discharge outlet; 5 is the material conveying pipe, 6 is the air distribution plate; 100 is the first bin, 200 is the second bin; 7 is the partition plate, 8 is the first dust removal device, 9 is the throttle valve, 10 is the gas supply pipe, 11 is the burner, 12 is the second dust removal device, 13 is the combustion device. Detailed implementation manners

[0047] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings.

[0048] Embodiment 1

[0049] As Figure 1 shown, an iron ore powder reduction device includes an upper reduction bin 1, a middle transition bin 2, a lower reduction bin 3, an air inlet bin 4, a material conveying pipe 5, an air inlet system, an air outlet system, a discharge system and a feed system.

[0050] The upper reduction bin 1, the middle transition bin 2, the lower reduction bin 3 and the air inlet bin 4 are sequentially connected to each other and are hermetically connected. By hermetically connecting the upper reduction bin 1, the middle transition bin 2, the lower reduction bin 3 and the air inlet bin 4 to form a whole, it helps to reduce the pressure drop of the high-temperature reduction gas, reduce the heat loss during gas transportation, ensure the fluidization effect of the solid material in the upper reduction bin 1, and improve the efficiency of the gas-solid reduction reaction in the upper reduction bin 1.

[0051] The lower reduction bin 3 is cylindrical, and the lower reduction bin 3 is inclined, with the end connected to the middle transition bin 2 being the high end and the end connected to the air inlet bin 4 being the low end. The upper reduction bin 1, the middle transition bin 2 and the air inlet bin 4 are all fixedly arranged relative to the ground. The upper reduction bin 1 is located above the middle transition bin 2. Both ends of the lower reduction bin 3 are rotatably arranged on the middle transition bin 2 and the air inlet bin 4. A air distribution plate 6 is arranged between the upper reduction bin 1 and the middle transition bin 2. Both ends of the material conveying pipe 5 are respectively connected to the upper reduction bin 1 and the lower reduction bin 3. Specifically, the material conveying pipe 5 sequentially passes through the air distribution plate 6, the middle transition bin 2 and is connected to the high-end opening of the lower reduction bin 3. The material conveying pipe 5 is inclined downward. The solid material slides from the upper reduction bin 1 to the lower reduction bin 3 under the action of its own gravity.

[0052] The upper reduction bin 1 is provided with an air outlet 101 and a feed inlet 102, and the intake bin 4 is provided with an air inlet 401 and a discharge outlet 402.

[0053] The intake system is connected to the air inlet 401 and is used to provide high-temperature reduction gas. The intake system includes a fan connected to a high-temperature reduction gas source.

[0054] The discharge system is connected to the discharge outlet 402, and the air outlet system is connected to the air outlet 101 and is used to treat the tail gas. Specifically, the air outlet system includes a second dust removal device 12.

[0055] The feed system includes a first bin 100 connected to the feed inlet 102 and is used to provide solid materials.

[0056] The upper reduction bin 1 is used for gas-solid reduction reaction.

[0057] The lower reduction bin 3 is used for solid-solid reduction reaction.

[0058] A throttle valve 9 is arranged between the intake system and the air inlet 401. The throttle valve 9 is arranged on the gas pipeline connected to the air inlet 401. The intake system is connected to the middle transition bin 2 through a make-up gas pipe 10.

[0059] In addition to iron ore powder, the solid materials at least include coal and / or coke particles.

[0060] An iron ore powder reduction method uses the above-mentioned iron ore powder reduction device and includes the following steps:

[0061] One branch of the high-temperature reduction gas passes through the throttle valve 9, enters the intake bin 4 from the air inlet 401, then sequentially passes through the lower reduction bin 3 and the middle transition bin 2, converges with another branch of high-temperature reduction gas from the gas source but coming through the make-up gas pipe 10 at the middle transition bin 2, then passes through the upper reduction bin 1, and finally is discharged from the air outlet 101.

[0062] Iron ore powder and coal enter the upper reduction bin 1 from the feed inlet 102, are heated and dried and undergo gas-solid reduction reaction in the upper reduction bin 1, then enter the lower reduction bin 3 through the material conveying pipe 5 for carbon-based solid-solid reduction reaction, and finally are discharged from the discharge outlet 402.

[0063] The high-temperature reduction gas includes CO and / or hydrogen.

[0064] Specifically, for the high-temperature reduction gas provided by the intake system, when the abundance is not greater than 40% (i.e., the reduction gas source capacity is insufficient), the temperature is 1000 °C. The process of preheating iron ore powder and coal using the upper reduction bin 1 and reducing iron ore powder with coal in the lower reduction bin 3 can be selected.

[0065] In this embodiment, coal enters the lower reduction bin 3 after being preheated together with iron ore powder in the upper reduction bin 1. The equipment structure is as Figure 1 shown. The upper reduction bin 1, the middle transition bin 2, the lower reduction bin 3 and the air inlet bin 4 are sequentially connected to each other and are sealed and communicated with each other. The upper reduction bin 1 and the lower reduction bin 3 are connected by a material conveying pipe 5. The air inlet system connected to the high-temperature reduction gas source is respectively communicated with the air inlet 401 and the supplementary air pipe 10. A combustion device may not be provided at the low-end side inlet of the lower reduction bin 3. The discharge system is communicated with the discharge port 402. The material conveying pipe 5 sequentially passes through the air distribution plate 6 and the middle transition bin 2 and is connected to the high-end opening of the lower reduction bin 3. The high-temperature gas rising from the middle transition bin 2 heats the material conveying pipe 5. The feeding system including the first bin 100 is connected to the feeding port 102 of the upper reduction bin 1. The air outlet 101 of the upper reduction bin 1 is connected to the air outlet system including the second dust removal device 12, and the second dust removal device 12 is a cyclone dust collector.

[0066] Among them, the 1000°C high-temperature flue gas containing 40% reduction gas enters the lower reduction bin 3 from the high-temperature reduction gas source, rapidly raises the temperature of the inner cavity of the lower reduction bin 3, ensures the uniform temperature in the lower reduction bin 3, provides the high-temperature conditions required for the reduction reaction of the iron ore and coal in the lower reduction bin 3, and also provides a part of the reducing agent to a considerable extent.

[0067] After the high-temperature reduction gas passes through the lower reduction bin 3 and the temperature drops to 700°C, it is mixed with the high-temperature reduction gas entering through the supplementary air pipe 10 from the high-temperature reduction gas source, and the temperature is raised to 800°C, which can further increase the reaction temperature of the upper reduction bin 1 and raise the temperature of the iron ore powder and coal after being preheated in the upper reduction bin 1. The gas passes through the air distribution plate 6 and enters the upper reduction bin 1 to heat the iron ore powder and coal in the upper reduction bin 1. The flue gas passing through the upper reduction bin 1 is discharged from the air outlet 101 of the upper reduction bin 1, and gas-solid separation is carried out by the cyclone dust collector of the second dust removal device 12, and then the gas enters the next process for treatment.

[0068] The iron ore powder and coal enter the upper reduction bin 1 from the first bin 100. Most of the particles are heated and undergo a limited gas-solid reduction reaction in the upper reduction bin 1. A small part of the fine particles are discharged from the air outlet 101 of the upper reduction bin 1 along with the flue gas and are separated by the second dust removal device 12. The separated particles enter the next process for treatment. This greatly avoids the risk of caking in the lower reduction bin 3. At the same time, the heating and reduction rate of the fine particles is fast, and they leave the system as early as possible, which can save the power consumption of the system.

[0069] After the iron ore powder particles and coal powder stay in the upper reduction bin 1 for a period of time, they are heated from the ambient temperature in the first bin 100 to 700°C, discharged through the material conveying pipe 5, and enter the lower reduction bin 3.

[0070] After being preheated, the iron ore powder particles and coal powder rapidly undergo a reduction reaction in the high-temperature environment and reduction atmosphere in the lower reduction bin 3.

[0071] Example 2

[0072] As Figure 2 shown, the difference from Example 1 is that the iron ore powder reduction device further includes a partition plate 7 and a first dust removal device 8.

[0073] The partition plate 7 is arranged in the middle transition bin 2 and above the high-end opening of the lower reduction bin 3, separating the middle transition bin 2 into a first transition bin 21 and a second transition bin 22 arranged up and down. The first transition bin 21 and the second transition bin 22 are interconnected through the first dust removal device 8. Specifically, as Figure 2 shown, the air inlet of the first dust removal device 8 is connected to the gas outlet of the second transition bin 22, the gas outlet of the first dust removal device 8 is connected to the air inlet of the first transition bin 21, and the solid outlet of the first dust removal device 8 is connected to the discharge port 402 and enters the discharge system through the discharge port 402.

[0074] Example 3

[0075] As Figure 3 shown, the difference from Example 1 is that the second dust removal device 12 is arranged in the internal space of the upper reduction bin 1. The gas inlet of the second dust removal device 12 is open to the internal space of the upper reduction bin 1, and the gas outlet of the second dust removal device 12 is connected to the gas outlet 101 of the upper reduction bin 1.

[0076] Example 4

[0077] As Figure 4 shown, the difference from Example 1 is that an independent coal inlet pipe 31 is provided at the high-end opening of the lower reduction bin 3.

[0078] The feeding system includes a second bin 200 connected to the coal inlet pipe 31.

[0079] When using the device of this example for reduction, only iron ore powder is added to the solid material in the first bin 100. The iron ore powder enters the upper reduction bin 1 from the first bin 100. Most of the particles are heated and undergo a limited reduction reaction in the upper reduction bin 1. A small number of fine particles are discharged from the gas outlet 101 of the upper reduction bin 1 along with the flue gas. After gas-solid separation by the second dust removal device 12, they enter the next process for treatment. This greatly avoids the risk of caking in the lower reduction bin 3. At the same time, the heating and reduction rate of the fine particles is fast, and they leave this system as early as possible, which can save the power consumption of this system.

[0080] After staying in the upper reduction bin 1 for a period of time, the iron ore powder particles are heated to 700 °C by the ambient temperature in the first bin 100, discharged through the material conveying pipe 5, and enter the lower reduction bin 3.

[0081] The coal inlet pipe 31 connected to the second bin 200 passes through the middle transition bin 2, and its outlet is arranged in the cavity on the high-end side of the lower reduction bin 3.

[0082] Coal enters the lower reduction bin 3 from the second bin 200 through the coal inlet pipe 31, is mixed with the heated coarse iron ore powder, and undergoes a carbon-based solid-solid reduction reaction in the lower reduction bin 3 to produce sponge iron or provide raw materials for smelting reduction, and finally is discharged from the discharge port 402 of the system of the present invention.

[0083] Example 5

[0084] As Figure 5 shown, the difference from Example 1 is that a burner 11 is arranged in the middle transition bin 2. The burner 11 is located below the air distribution plate 6. A combustion device 13 is arranged at the low-end opening of the lower reduction bin 3. The throttle valve 9 and the make-up air pipe 10 arranged on the intake side of the air inlet 401 are cancelled.

[0085] Since the high temperature generated by the burner 11 will affect the service life of the subsequent components, the air distribution plate 6 is provided with a water cooling device for water cooling the air distribution plate 6.

[0086] The material conveying pipe 5 is arranged outside the upper reduction bin 1, the middle transition bin 2 and the lower reduction bin 3, and the material conveying pipe 5 is also inclined. At the same time, the material conveying pipe 5 no longer penetrates through the air distribution plate 6, but bypasses the high-temperature section of the middle transition bin 2 and enters the cavity of the lower reduction bin 3 from the outside to avoid burning of the material conveying pipe 5 by the high-temperature flame. The solid material in the first bin 100 no longer directly uses coal, but waste coke particles produced by coking.

[0087] The normal-temperature reducing gas enters the lower reduction bin 3 from the gas source, burns a part at the combustion device 13 to make the flue gas temperature here reach 1000 °C, provides the high-temperature conditions required for the reduction reaction of the iron ore and coal in the lower reduction bin 3, and also provides a part of the reducing agent to a considerable extent.

[0088] After the high-temperature reducing gas passes through the lower reduction bin 3, the temperature drops to 700 °C. By burning all the remaining reducing gas in the middle transition bin 2, the temperature of the high-temperature gas is further increased to 1000 °C to make it no longer toxic and dangerous. Then, the gas passes through the air distribution plate 6 to heat the iron ore powder and coke particles in the upper reduction bin 1. The flue gas passing through the upper reduction bin 1 is discharged from the air outlet 101, undergoes gas-solid separation by the second dust removal device 12, and then enters the next process for treatment.

[0089] Iron ore powder and coke particles enter the upper reduction bin 1 from the first bin 100. Most of the particles are heated and undergo limited reduction reactions in the upper reduction bin 1. A small number of fine particles are discharged from the gas outlet 101 of the upper reduction bin 1 along with the flue gas. After gas-solid separation by the second dust removal device 12, they enter the next process for treatment. This greatly avoids the risk of ring formation in the lower reduction bin 3. At the same time, the heating and reduction rate of the fine particles is fast, and leaving the system as early as possible can save the power consumption of the system.

[0090] After the iron ore powder particles and coke particles stay in the upper reduction bin 1 for a period of time, they are heated from the ambient temperature in the first bin 100 to 850 °C, discharged through the material conveying pipe 5, and enter the lower reduction bin 3, where a carbon-based solid-solid reduction reaction occurs to produce sponge iron or provide raw materials for smelting reduction, and finally discharged from the system through the discharge port 402.

[0091] Those skilled in the art of this technology should recognize that the above embodiments are only used to illustrate the present invention, rather than to limit the present invention. As long as it is within the scope of the spirit of the present invention, changes and modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. An iron ore powder reduction device, characterized in that: It comprises an upper reduction bin (1), a middle transition bin (2), a lower reduction bin (3), an air intake bin (4), a material conveying pipe (5), an air intake system, an air outlet system, a material outlet system and a material feed system; The upper reduction chamber (1), the middle transition chamber (2), the lower reduction chamber (3) and the air intake chamber (4) are sequentially connected to each other and are sealed and interconnected; The upper reduction bin (1), the middle transition bin (2) and the air intake bin (4) are all fixedly arranged. The upper reduction bin (1) is located above the middle transition bin (2). The lower reduction bin (3) is cylindrical. The lower reduction bin (3) is rotatable and is sealed and connected to the middle transition bin (2) and the air intake bin (4). The lower reduction bin (3) is inclined at a certain angle to the ground. The end connected to the middle transition bin (2) is the high end, and the end connected to the air intake bin (4) is the low end. An air distribution plate (6) is arranged between the upper reduction bin (1) and the middle transition bin (2). The two ends of the material conveying pipe (5) are respectively connected to the upper reduction bin (1) and the lower reduction bin (3). The upper reduction bin (1) is provided with an air outlet (101) and a material inlet (102), and the air inlet bin (4) is provided with an air inlet (401) and a material outlet (402); The air intake system is connected to the air intake port (401) and is used to provide reducing gas; The material discharge system is connected to the material discharge port (402), and the gas discharge system is connected to the gas outlet (101); The feeding system is connected to the feeding port (102).

2. The iron ore powder reduction device according to claim 1, characterized in that: It also includes a partition (7) and a first dust removal device (8); The partition plate (7) is arranged in the middle transition bin (2) and is located above the opening of the lower reduction bin (3), dividing the middle transition bin (2) into a first transition bin (21) and a second transition bin (22) arranged one above the other, the first transition bin (21) and the second transition bin (22) being interconnected via a first dust removal device (8).

3. The iron ore powder reduction device according to claim 1, characterized in that: It also includes a throttle valve (9) and an air supply pipe (10); A throttle valve (9) is provided between the air intake system and the air intake port (401), and the air intake system is connected to the middle transition chamber (2) via an air supply pipe (10).

4. The iron ore powder reduction device according to claim 1, characterized in that: A heating system is provided on the air supply pipeline.

5. The iron ore powder reduction device according to claim 4, characterized in that: The heating system is an oxygen-containing gas combustion heating system.

6. The iron ore powder reduction device according to claim 1, characterized in that: The high end opening of the lower reduction bin (3) is provided with an independent coal inlet pipeline (31); The feeding system comprises a second silo (200) connected to the coal feeding pipeline (31).

7. The iron ore powder reduction device according to claim 1, characterized in that: The material conveying pipe (5) passes through the air distribution plate (6), the middle transition bin (2) and the high end opening of the lower reduction bin (3) in sequence and is connected.

8. The iron ore powder reduction device according to claim 1, characterized in that: A burner (11) is arranged in the middle transition chamber (2).

9. The iron ore powder reduction device according to claim 8, characterized in that: The air distribution plate (6) is provided with a water cooling device, and the water cooling device is used to water-cool the air distribution plate (6).

10. The iron ore powder reduction device according to claim 8, characterized in that: The material conveying pipe (5) is arranged outside the upper reduction bin (1) and the middle transition bin (2); after entering the middle transition bin (2) from the outside, the material conveying pipe enters the lower reduction bin (3).

11. The iron ore powder reduction device according to claim 1, characterized in that: The air outlet system comprises a second dust removal device (12).

12. The iron ore powder reduction device according to claim 11, characterized in that: The second dust removal device (12) is arranged in the cavity of the upper reduction bin (1).

13. The iron ore powder reduction device according to claim 1, characterized in that: A combustion device (13) is provided at the lower side opening of the lower reduction bin (3).

14. The iron ore powder reduction device according to claim 6, characterized in that: The solid material in the second silo (200) at least comprises carbonaceous material, and the carbonaceous material is one or more of coal, coke particles and / or coke powder.

15. A method for reducing iron ore powder, using the iron ore powder reduction device according to claim 1, characterized in that: The following steps are involved: The reducing gas enters the air inlet (4) from the air inlet (401), then passes through the lower reduction chamber (3), the middle transition chamber (2) and the upper reduction chamber (1) in sequence, and finally is discharged from the air outlet (101); The iron ore powder enters the upper reduction bin (1) from the feed port (102), undergoes heating and / or a physical and chemical process including a gas-solid reduction reaction in the upper reduction bin (1), then enters the lower reduction bin (3) through the material conveying pipe (5), undergoes a solid-solid reduction reaction and a limited gas-solid reduction reaction, and is finally discharged from the discharge port (402).

16. The iron ore powder reduction method according to claim 15, characterized in that: The reducing gas is a high-temperature reducing gas including H2 and / or CO.

17. The iron ore powder reduction method according to claim 15, characterized in that: When the reducing gas enters the lower reduction chamber (3) and / or the middle transition chamber (2), a portion of it is burned to provide heat for subsequent processes.

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