Direct reduction iron device and method using hydrogen-rich gas heated by hot blast furnace

Abstract

The present application relates to a hydrogen-rich gas direct reduction iron device and method using hot blast stove, comprising a shaft furnace, a hot blast stove, a gas system, a combustion air system and a hydrogen-rich reducing gas preparation system; the shaft furnace comprises an upper reduction section and a lower primary preheating section, and the hot blast stove comprises an upper combustion section and a lower heat storage section; the gas system and the combustion air system pass the gas and the combustion air into the combustion section for combustion, and the combustion is discharged through the heat storage section; the hydrogen-rich reducing gas preparation system passes the low-temperature hydrogen-rich reducing gas into the primary preheating section to discharge the medium-temperature hydrogen-rich reducing gas, passes the medium-temperature hydrogen-rich reducing gas into the heat storage section to discharge the high-temperature hydrogen-rich reducing gas, and passes the high-temperature hydrogen-rich reducing gas into the reduction section for direct reduction of iron, and then discharges the top gas from the top of the shaft furnace. Compared with the traditional process, the present application adopts a circulating multi-stage utilization process, avoids the problem of reduction of the reducing gas in multiple cycles, keeps the shaft furnace in a stable reduction state at all times, and improves the metallization rate of the direct reduction iron and the product quality.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen metallurgical technology of hydrogen-based vertical shaft furnace for direct reduction of iron ore, and specifically relates to a device and method for direct reduction of iron by heating hydrogen-rich gas with a hot blast stove. Background Technology

[0002] On September 22, 2020, at the United Nations General Assembly, China aimed to peak its carbon dioxide emissions before 2030 and strive to achieve carbon neutrality before 2060. In 2023, China's total carbon emissions were approximately 12 billion tons of CO2 (including energy activities and industrial processes), accounting for about 30% of global emissions (IEA and CEADS data). While carbon intensity continued to decline, the total emissions remained high. The steel industry is China's second-largest carbon-emitting industrial sector (accounting for approximately 15-18% of national emissions), with emissions of approximately 1.8-2 billion tons of CO2 in 2023. China's carbon emissions per ton of steel are approximately 1.8-2.0 tons of CO2, higher than the global average (1.4 tons), mainly due to its high dependence on coal (coke accounts for 70%). The hydrogen metallurgical electric arc furnace process has the best potential to reduce carbon emissions to near zero, essentially achieving carbon neutrality, and is therefore an important development direction for achieving the dual carbon goals.

[0003] The challenge of replacing the long-process steelmaking with a short-process electric arc furnace (EAF) for hydrogen metallurgy lies in the production of the EAF raw materials. The current main approach is to use hydrogen smelting for direct reduced iron (DRI) and then use DRI as the EAF raw material. Using pure hydrogen can eliminate CO2 emissions throughout the entire process, achieving true green metallurgy.

[0004] Replacing the long-process steelmaking with a short-process electric arc furnace (EAF) using hydrogen metallurgy presents a challenge in the production of the EAF feedstock. The current main approach is to utilize hydrogen smelting for direct reduced iron (DRI) and then use DRI as the EAF feedstock. Using pure hydrogen would eliminate CO2 emissions throughout the process, achieving true green metallurgy. However, the hydrogen smelting DRI process has the following drawbacks:

[0005] 1. Hydrogen embrittlement in materials: Under high temperature and pressure, hydrogen molecules decompose into hydrogen atoms, which penetrate into the metal, causing a decrease in the toughness of the metal material and the formation of cracks, i.e., "hydrogen embrittlement". The higher the temperature, the more significant the hydrogen embrittlement effect.

[0006] 2. High-temperature oxidation resistance: Heating elements and furnace materials must have good oxidation resistance at 1100°C. However, the anti-oxidation layers of many heat-resistant alloys (such as alumina and chromium oxide) will be destroyed in a hydrogen reducing atmosphere, thus losing their protective function.

[0007] 3. Hydrogen Leakage and Explosion Risks: Hydrogen is the gas with the lowest density, lowest viscosity, and strongest diffusion ability, making it extremely prone to leakage. When mixed with air (explosion limits 4%~75%), it will violently explode upon contact with an open flame or high temperature.

[0008] 4. High thermal conductivity and high specific heat capacity: Hydrogen has extremely high thermal conductivity (7 times that of air) and high specific heat capacity, which means that heating it requires huge power and places extremely high demands on the efficiency of the heat exchanger.

[0009] Meanwhile, some Chinese patents have also proposed a process for directly reducing iron using hydrogen smelting, for example:

[0010] CN120627647A A design scheme for a hydrogen-based vertical furnace with pure hydrogen electric heating: The hydrogen electric heating furnace adopts a partitioned structure design, with hydrogen flowing in a nickel-based alloy heating pipe and silicon carbide rods arranged inside the heating furnace cavity.

[0011] CN102912058A A hot air valve for a hot blast stove system of a direct reduction iron vertical furnace: This provides a hot air valve for a hot blast stove system of a direct reduction iron vertical furnace with good sealing effect and long service life.

[0012] CN119932243A A hydrogen direct-injection and top gas circulation vertical furnace system and process: Provides a hydrogen direct-injection and top gas circulation vertical furnace system and process.

[0013] CN119803052A A split-type high-temperature electric heating device for hydrogen-based vertical furnace: This invention relates to a design scheme for hydrogen electric heating equipment adapted to hydrogen-based vertical furnace. The high-temperature electric heating of pure hydrogen adopts a split-type structure design, with the heating rod distribution cavity and the hydrogen heating cavity isolated from each other; the heating furnace adopts a three-section structure design.

[0014] CN119242878A describes a hydrogen metallurgical supplementary heating device and its usage method: The device includes a heat exchanger, a microwave heating device, and a pressure swing adsorption device. Water vapor separated in the pressure swing adsorption device enters the microwave heating device for heating. The heated water vapor also enters the heat exchanger to exchange heat with pure hydrogen. The pure hydrogen can be heated to 700-950°C.

[0015] CN118406824A Pure Hydrogen Reduction Vertical Furnace System and Process Method: A hydrogen electric heating furnace unit is used to heat mixed hydrogen to a target temperature range.

[0016] However, as can be seen from the above patents, the current direct reduction of pure hydrogen mainly uses electric heating to achieve the target temperature.

[0017] In the future, with the improvement of the green hydrogen supply chain and the development of the carbon market, hydrogen-based direct reduced iron is expected to be widely adopted after 2030, becoming a key path for decarbonization in the steel industry. China needs to strengthen technological research and development and supply chain collaboration to promote the industrialization of hydrogen metallurgy.

[0018] In view of this, the present invention is hereby proposed. Summary of the Invention

[0019] The purpose of this invention is to provide an apparatus and method for directly reducing iron by heating hydrogen-rich gas in a hot blast furnace, so as to solve the technical problems mentioned in the background art.

[0020] To achieve one of the above objectives, the present invention provides the following technical solution:

[0021] A device for direct reduction of iron by heating hydrogen-rich gas with a hot blast stove includes a vertical furnace, a hot blast stove, a gas system, a combustion air system, and a hydrogen-rich reducing gas preparation system.

[0022] The vertical furnace includes an upper reduction section and a lower primary preheating section, and the hot blast stove includes an upper combustion section and a lower heat storage section.

[0023] The gas system and the combustion air system respectively introduce gas and combustion air into the combustion section for combustion, and the combustion is discharged through the heat storage section after combustion.

[0024] The hydrogen-rich reducing gas preparation system introduces low-temperature hydrogen-rich reducing gas into the primary preheating section and then discharges medium-temperature hydrogen-rich reducing gas. The medium-temperature hydrogen-rich reducing gas is then introduced into the heat storage section and then discharged as high-temperature hydrogen-rich reducing gas. The high-temperature hydrogen-rich reducing gas is then introduced into the reduction section for direct reduction of iron, and finally discharged as top gas from the top of the vertical furnace.

[0025] Preferably, there are 2-4 hot air furnaces, and each hot air furnace operates alternately.

[0026] Preferably, after the gas is discharged from the furnace top, it passes through a cyclone dust collector and a high-temperature dehydrator in sequence before being introduced into the combustion section along with the fuel gas.

[0027] Preferably, the heat storage section is constructed of refractory bricks, and the refractory bricks have holes.

[0028] A method for directly reducing iron by heating hydrogen-rich gas using a hot blast furnace, utilizing the aforementioned apparatus for directly reducing iron by heating hydrogen-rich gas using a hot blast furnace, includes the following specific steps:

[0029] S100: The combustion gas and combustion air-supporting gas in the combustion system and combustion air system are introduced into the combustion section for combustion to generate flue gas;

[0030] S200: Flue gas flows downward from the top of the hot blast stove under negative pressure and passes through the heat storage section. The refractory bricks in the heat storage section absorb and store the heat of the flue gas.

[0031] S300: Cut off the combustion system and the combustion air system, stop the supply of combustion gas and combustion air to the combustion section, and introduce low-temperature hydrogen-rich reducing gas into the primary preheating section of the hydrogen-rich reducing gas preparation system for preheating. After preheating, medium-temperature hydrogen-rich reducing gas is discharged.

[0032] S400, medium-temperature hydrogen-rich reducing gas is introduced into the heat storage section for secondary preheating, and high-temperature hydrogen-rich reducing gas is discharged after secondary preheating.

[0033] S500, high-temperature hydrogen-rich reducing gas is introduced into the reduction section for direct reduction of iron, and then the top gas is discharged from the top of the vertical furnace.

[0034] Preferably, there are 2-4 hot air furnaces, and each hot air furnace operates alternately.

[0035] Preferably, after the gas is discharged from the furnace top, it passes through a cyclone dust collector and a high-temperature dehydrator in sequence before being introduced into the combustion section along with the fuel gas.

[0036] Preferably, the heat storage section is constructed of refractory bricks, and the refractory bricks have holes.

[0037] Compared with the prior art, the beneficial effects of the present invention are:

[0038] 1. The hydrogen-rich reducing gas first enters the lower end of the vertical furnace and comes into contact with the hot direct reduced iron inside the furnace. It is preheated to above 200 degrees Celsius before entering the hydrogen-rich hot blast stove. The heating range of the hot blast stove is 200~1050 degrees Celsius, which shortens the heating range of the hot blast stove while cooling the direct reduced iron.

[0039] 2. Compared to traditional reducing gas recycling processes, this patented hydrogen-rich reducing gas employs a non-recycling approach, combining recycling and multi-stage utilization. In the process flow, it sequentially serves as cooling gas—reducing gas—furnace top gas—partially recycled gas—partially supplementary fuel for the hot blast stove. This avoids the problem of reduced reducing power due to multiple recycling of the reducing gas, ensuring a stable reducing state within the vertical shaft furnace and improving the metallization rate and product quality of direct reduced iron. Taking coke oven gas as an example, because it contains gases such as methane that do not participate in the reduction reaction, and because inert gases such as nitrogen are required in the production process, the inert gases such as nitrogen cannot react during the recycling of reducing gas. This leads to an increase in the proportion of methane and nitrogen in the reducing gas after multiple recyclings, reducing reducing power and causing a decrease in productivity. In this patent, methane can participate in the fuel utilization after the vertical shaft furnace, and unreacted components such as nitrogen are discharged after one use. Therefore, the reducing atmosphere within the vertical shaft furnace can always remain stable.

[0040] 3. Use two or more hot blast stoves to heat the hydrogen-rich reducing gas, and use them alternately to ensure a continuous supply of high-temperature reducing gas to the vertical furnace.

[0041] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0042] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is an arrangement view of an apparatus for directly reducing iron by heating hydrogen-rich gas using a hot blast furnace, provided as an embodiment of the present invention.

[0044] Figure 2 This is an arrangement view of an apparatus for directly reducing iron by heating hydrogen-rich gas using a hot blast furnace, according to another embodiment of the present invention.

[0045] The diagram is shown below:

[0046] 1. Vertical shaft furnace; 2. Hot blast stove; 3. Gas system; 4. Combustion air system; 5. Hydrogen-rich reducing gas preparation system; 6. Reduction section; 7. Primary preheating section; 8. Combustion section; 9. Heat storage section; 10. Cyclone dust collector; 11. High-temperature dehydrator; 12. Iron oxide raw material; 13. Raw material feeding port. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0048] like Figure 1-2As shown, this embodiment of the invention provides a device for direct reduction of iron using a hot blast stove 2 to heat hydrogen-rich gas. The device includes a vertical furnace 1, a hot blast stove 2, a gas system 3, a combustion air system 4, and a hydrogen-rich reducing gas preparation system 5. The vertical furnace 1 includes an upper reduction section 6 and a lower primary preheating section 7. The hot blast stove 2 includes an upper combustion section 8 and a lower heat storage section 9. The gas system 3 and the combustion air system 4 respectively introduce gas and combustion air into the combustion section 8 for combustion, and the combustion gases are discharged through the heat storage section 9. The hydrogen-rich reducing gas preparation system 5 introduces low-temperature hydrogen-rich reducing gas into the primary preheating section 7 and then discharges medium-temperature hydrogen-rich reducing gas. The medium-temperature hydrogen-rich reducing gas is then introduced into the heat storage section 9 and then discharged as high-temperature hydrogen-rich reducing gas. The high-temperature hydrogen-rich reducing gas is introduced into the reduction section 6 for direct reduction of iron, and then the top gas is discharged from the top of the vertical furnace 1.

[0049] The hot blast stove 2 is provided in 2-4 units, with each hot blast stove 2 operating alternately. After the gas from the furnace top is discharged, it passes sequentially through a cyclone dust collector 10 and a high-temperature dehydrator 11 before being introduced into the combustion section 8 along with the fuel gas. In this way, a portion of the furnace top gas (approximately 70% unreacted reducing gas) is used as supplementary fuel gas for the hot blast stove after dust and water removal, rather than being reused in the vertical furnace, thus avoiding the adverse effects of components such as methane and nitrogen on the overall reducing atmosphere.

[0050] In addition, the heat storage section 9 is made of refractory bricks, and the refractory bricks are provided with holes.

[0051] This invention also provides a method for directly reducing iron by heating hydrogen-rich gas using a hot blast furnace 2. The method utilizes the aforementioned apparatus for directly reducing iron by heating hydrogen-rich gas using a hot blast furnace 2, and the specific steps include the following:

[0052] S100, The combustion gas and combustion air-supporting gas in the combustion system and combustion air system 4 are introduced into the combustion section 8 for combustion to generate flue gas;

[0053] S200, flue gas flows downward from the top of the hot blast stove 2 under negative pressure and passes through the heat storage section 9. The refractory bricks in the heat storage section 9 absorb and store the heat of the flue gas.

[0054] S300, cut off the combustion system and the combustion air system 4, stop the supply of combustion gas and combustion air to the combustion section 8, and introduce the low temperature hydrogen-rich reducing gas into the primary preheating section 7 through the hydrogen-rich reducing gas preparation system 5 for preheating. After preheating, the medium temperature hydrogen-rich reducing gas is discharged.

[0055] S400, medium-temperature hydrogen-rich reducing gas is introduced into the heat storage section 9 for secondary preheating, and high-temperature hydrogen-rich reducing gas is discharged after secondary preheating.

[0056] S500, high-temperature hydrogen-rich reducing gas is introduced into reduction section 6 for direct reduction of iron, and then the top gas is discharged from the top of vertical furnace 1.

[0057] In this invention, since the combustion product of hydrogen is water, and the reaction absorbs a large amount of heat, direct combustion heating cannot be considered; instead, an indirect heating process must be chosen. Specifically, this includes the following two stages:

[0058] Phase 1: Combustion Period (Heat Storage Period)

[0059] The task at this stage is to use the heat from the combustion of gas to heat the regenerator.

[0060] Combustion: Coal gas (usually a mixture of blast furnace gas and coke oven gas) and combustion air are ejected through the burner on the top of the furnace and rapidly and thoroughly mixed and burned in the combustion chamber below the hot blast stove dome, producing high-temperature flue gas at 1300-1400°C.

[0061] Downward flow: Under the negative pressure inside the furnace, the high-temperature flue gas flows downward from the top of the furnace and passes through the regenerator chamber evenly and comprehensively.

[0062] Heat transfer: The regenerator is filled with refractory checkerboard bricks (with perforations). When high-temperature flue gas flows through the checkerboard bricks, the bricks absorb and store the heat of the flue gas, and their own temperature gradually increases (up to over 1200°C). Meanwhile, the flue gas itself gradually decreases in temperature due to the absorption of heat, eventually becoming low-temperature flue gas at 150-200°C.

[0063] Smoke exhaust: Low-temperature flue gas is discharged from the flue gas outlet at the bottom of the hot blast stove and is discharged into the atmosphere through the flue and chimney.

[0064] Phase Two: Air Supply Period (Heat Release Period)

[0065] The task at this stage is to use the heat stored in the checker bricks to heat the cold air sent to the blast furnace.

[0066] Switching valves: By using the valve system, the gas and combustion air are cut off, and combustion is stopped.

[0067] Primary preheating of hydrogen-rich reducing gas: Room-temperature hydrogen-rich reducing gas (approximately 100-200°C) from the blower first enters the lower part of the vertical shaft furnace, contacting the hot direct reduced iron inside and preheating it to above 200°C. This preliminary preheating allows the hydrogen-rich reducing gas to operate within the hot blast stove's heating range of 200-1050°C, shortening the heating range of the hot blast stove while cooling the direct reduced iron, and simultaneously saving on the gas consumption of the hot blast stove.

[0068] Upward Flow & Heating: After preliminary preheating, the hydrogen-rich reducing gas enters the hot blast furnace and flows upward through the already heated checker bricks. During this counter-current upward flow, the hydrogen-rich reducing gas undergoes vigorous heat exchange with the high-temperature checker bricks, causing the temperature to rise rapidly. This downward flow of flue gas ensures sufficient heat exchange between the hydrogen-rich reducing gas and the checker bricks, minimizing heat loss.

[0069] Hot air output: The hydrogen-rich reducing gas, heated to the target temperature (above 1250°C), is sent out from the hot air outlet at the top of the furnace and stably fed into the reduction section of the vertical furnace through the hot air pipe and the hot air duct.

[0070] This air supply process lasts approximately 40-60 minutes, until the heat stored in the checker bricks is almost exhausted and the temperature drops to a certain level. At this point, the system automatically switches valves, causing the hot blast stove to switch from the "air supply period" back to the "combustion period," and another hot blast stove that has completed heat storage takes over the air supply task. This cycle repeats continuously, ensuring a continuous supply of high-temperature reducing gas to the vertical furnace.

[0071] In this invention, compared to traditional reducing gas recycling processes, hydrogen-rich reducing gas employs a recycling + multi-stage utilization process. In the process flow, it sequentially serves as cooling gas – reducing gas – furnace top gas – a portion of the recycled gas – a portion of the hot blast stove supplementary fuel. This avoids the problem of reduced reducing power due to multiple recycling of reducing gas, ensuring a stable reducing state within the vertical shaft furnace, thus improving the metallization rate and product quality of direct reduced iron. Taking coke oven gas as an example, because it contains gases such as methane that do not participate in the reduction reaction, and because inert gases such as nitrogen are required in the production process, the inert gases such as nitrogen cannot react during the recycling of reducing gas. This leads to an increase in the proportion of methane and nitrogen in the reducing gas after multiple recyclings, reducing reducing power and causing a decrease in productivity. In this patent, methane can participate in the fuel utilization after the vertical shaft furnace, and unreacted components such as nitrogen are discharged after one use. Therefore, the reducing atmosphere within the vertical shaft furnace can always remain stable.

[0072] Furthermore, in traditional processes, most reducing gas heating devices are located on the ground, while the air inlet of the vertical furnace is tens of meters high, with the intermediate pipes containing high-temperature hydrogen gas at around 1100 degrees Celsius, posing a significant safety hazard. This invention employs a hot blast stove with the combustion section at the top, allowing the hot air outlet elevation to be aligned with the vertical furnace air inlet, minimizing the pipe distance for the 1100-degree Celsius high-temperature hydrogen gas and improving system safety. Additionally, the high-temperature hydrogen-rich pipes utilize Haynes 214 material. Haynes 214, after undergoing 1000 hours of testing at 980 degrees Celsius in a methane-hydrogen mixture (CH4 / H2=1:4) environment, exhibits a carburized layer depth of less than 5 micrometers, far superior to the 200-micrometer penetration of 304 stainless steel, minimizing the impact of hydrogen embrittlement.

[0073] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0074] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0075] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0076] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

Claims

1. A device for directly reducing iron by heating hydrogen-rich gas using a hot blast furnace, characterized in that, This includes a vertical shaft furnace, a hot blast stove, a gas system, a combustion air system, and a hydrogen-rich reducing gas preparation system; The vertical furnace includes an upper reduction section and a lower primary preheating section, and the hot blast stove includes an upper combustion section and a lower heat storage section. The gas system and the combustion air system respectively introduce gas and combustion air into the combustion section for combustion, and the combustion is discharged through the heat storage section after combustion. The hydrogen-rich reducing gas preparation system introduces low-temperature hydrogen-rich reducing gas into the primary preheating section and then discharges medium-temperature hydrogen-rich reducing gas. The medium-temperature hydrogen-rich reducing gas is then introduced into the heat storage section and then discharged as high-temperature hydrogen-rich reducing gas. The high-temperature hydrogen-rich reducing gas is then introduced into the reduction section for direct reduction of iron, and finally discharged as top gas from the top of the vertical furnace.

2. The apparatus for directly reducing iron by heating hydrogen-rich gas using a hot blast furnace according to claim 1, characterized in that, There are 2-4 hot air furnaces, and each hot air furnace operates alternately.

3. The apparatus for directly reducing iron by heating hydrogen-rich gas using a hot blast furnace according to claim 2, characterized in that, After the gas is discharged from the top of the furnace, it passes through a cyclone dust collector and a high-temperature dehydrator in sequence before being fed into the combustion section along with the fuel gas.

4. The apparatus for direct reduction of iron using a hot blast furnace heated with hydrogen-rich gas according to claim 3, characterized in that, The heat storage section is constructed of refractory bricks, and the refractory bricks have holes.

5. A method for directly reducing iron by heating hydrogen-rich gas in a hot blast furnace, characterized in that, The specific steps of the device for direct reduction of iron by heating hydrogen-rich gas with a hot blast furnace as described in claim 1 include the following: S100: The combustion gas and combustion air-supporting gas in the combustion system and combustion air system are introduced into the combustion section for combustion to generate flue gas; S200: Flue gas flows downward from the top of the hot blast stove under negative pressure and passes through the heat storage section. The refractory bricks in the heat storage section absorb and store the heat of the flue gas. S300: Cut off the combustion system and the combustion air system, stop the supply of combustion gas and combustion air to the combustion section, and introduce low-temperature hydrogen-rich reducing gas into the primary preheating section of the hydrogen-rich reducing gas preparation system for preheating. After preheating, medium-temperature hydrogen-rich reducing gas is discharged. S400, medium-temperature hydrogen-rich reducing gas is introduced into the heat storage section for secondary preheating, and high-temperature hydrogen-rich reducing gas is discharged after secondary preheating. S500, high-temperature hydrogen-rich reducing gas is introduced into the reduction section for direct reduction of iron, and then the top gas is discharged from the top of the vertical furnace.

6. The method for directly reducing iron by heating hydrogen-rich gas in a hot blast furnace according to claim 5, characterized in that, There are 2-4 hot air furnaces, and each hot air furnace operates alternately.

7. The method for directly reducing iron by heating hydrogen-rich gas in a hot blast furnace according to claim 6, characterized in that, After the gas is discharged from the top of the furnace, it passes through a cyclone dust collector and a high-temperature dehydrator in sequence before being fed into the combustion section along with the fuel gas.

8. The method for directly reducing iron by heating hydrogen-rich gas in a hot blast furnace according to claim 7, characterized in that, The heat storage section is constructed of refractory bricks, and the refractory bricks have holes.

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