A system and method for hydrogen metallurgical steelmaking based on hydrogen production from methanol

Abstract

The present application relates to a kind of hydrogen metallurgical steelmaking based on hydrogen of methanol, belong to direct steelmaking technical field.System and method for technical scheme: methanol is generated by cleavage H2 and CO mixed gas;H2 and CO mixed gas as reducing agent enters reaction tower and is injected into the reaction of ground iron powder, and is reduced to metallized iron powder in 900 ℃-1100 ℃ environment;Methanol and water are prepared high-purity hydrogen by reforming, and supply plasma generator as working medium;Metallized iron powder enters the molten pool of smelting furnace, and 3000 ℃ ultrahigh temperature hydrogen plasma generated by plasma generator is injected into the molten pool at high speed to form gushing spring stirring, realize slag iron separation and complete direct steelmaking.The present application adopts the strategy of hierarchical energy supply, gradient temperature reaction, closed loop circulation, uses methanol as the double carrier of hydrogen and carbon, directly produces low-carbon molten steel by gradient temperature field control, and realizes carbon element full closed loop circulation, eliminates the contradiction between high carbon emission and full hydrogen metallurgy difficult liquid slagging in existing steel smelting technology.

Description

Technical Field

[0001] This invention relates to a system and method for hydrogen metallurgical steelmaking based on methanol-to-hydrogen production, belonging to the field of direct steelmaking technology. Background Technology

[0002] The steel industry is one of the world's highest carbon-emitting manufacturing industries. Currently, over 90% of the global steel industry relies on the blast furnace-converter long process, which depends on high-quality coking coal and has extremely high carbon emissions (approximately 1.8 tons of CO2 per ton of steel). Furthermore, the process is lengthy and requires significant investment. With the acceleration of global carbon neutrality, especially the implementation of the EU's Carbon Border Adjustment Mechanism (CBAM), traditional blast furnace ironmaking faces enormous challenges, and the steel industry faces immense decarbonization pressure. Currently, the mainstream alternative technologies fall into two categories: 1. All-hydrogen metallurgy: This utilizes hydrogen to reduce iron ore, producing solid sponge iron. However, due to the strong reducing properties of hydrogen, it is difficult to maintain a high-carbon environment within the furnace, resulting in the inability to achieve liquid slag-iron separation. Additionally, the production, storage, and transportation costs of hydrogen are extremely high. 2. Smelting reduction technology (such as Corex and Finex): Although it eliminates coke, it still requires pulverized coal, and the furnace top gas is typically burned as fuel, failing to achieve carbon closed-loop production. The product is high-carbon pig iron, which still requires converter refining.

[0003] There are many patent applications for direct steelmaking technology, such as Chinese patent CN108374067B, "An apparatus and method for rapid reduction direct steelmaking." However, these technologies have several problems: they rely on gaseous hydrogen as the main reducing agent, resulting in high storage and transportation costs and the risk of hydrogen embrittlement; they require additional hydrogen storage and transportation facilities, increasing system complexity; hydrogen flow control is difficult, easily causing fluctuations in the reducing atmosphere; the smelting zone temperature reaches 1580-1680℃, placing extremely high demands on refractory materials; equipment maintenance is difficult under high temperatures, increasing the frequency of repairs; and the proportion of heat loss is high, leading to low energy utilization efficiency. The advantages of this technology are relatively low; it requires the use of ultra-pure iron concentrate (TFe≥71.5%), demanding stringent raw material requirements – fine grinding and refining pretreatment are necessary, increasing process steps and costs; it has low tolerance for raw material impurities and poor adaptability; pure hydrogen reduction easily leads to over-reduction, affecting product quality; it lacks carbon source supplementation, requiring additional pulverized coal injection to maintain carbon balance; the molten pool stirring effect relies on mechanical devices, resulting in relatively poor uniformity; the product carbon content range is wide (0.01-0.4%), with limited control precision – it relies on pulverized coal injection volume adjustment, resulting in slow control response speed; and the product quality fluctuates relatively greatly. Chinese patent CN110423854B, "An Electrical All-Hydrogen Flash Reduction Direct Steelmaking System and Process," has the following problems: it completely excludes carbon elements, using only pure hydrogen as a reducing agent. Its tail gas treatment system can only condense and recover water vapor for reuse in electrolysis, forming a single water circulation system; it mainly relies on bottom-blown hydrogen / oxygen to generate bubbles for stirring, which is inefficient and poses a risk of hydrogen absorption by molten steel.

[0004] In summary, the technical problems in this field are as follows: 1. Carbon emission and storage challenges: Traditional blast furnaces rely on coke, resulting in extremely high carbon emissions (approximately 1.8 tons of CO2 per ton of steel); while pure hydrogen metallurgy is low-carbon, hydrogen storage and transportation costs are high, it is dangerous (hydrogen embrittlement), and it is difficult to handle the slag discharge problem of low-grade ore. 2. Lengthy product form and processes: Existing hydrogen metallurgy (such as HYBRIT) typically produces solid sponge iron (DRI), which cannot directly separate gangue and requires secondary melting before steelmaking, resulting in a long process and high energy consumption. 3. Metallurgical bottlenecks in low-temperature melting: When performing molten reduction at temperatures below 1500℃, technical bottlenecks are encountered, including high slag viscosity ("dead slag"), poor fluidity, and difficulty in dephosphorization. Summary of the Invention

[0005] This invention proposes a system and method for hydrogen metallurgical steelmaking based on methanol-to-hydrogen. It directly produces steel through low-temperature molten reduction of methanol cracked gas, employing a strategy of staged energy supply, gradient temperature reaction, and closed-loop circulation. Utilizing methanol as a dual carrier of hydrogen and carbon, and controlled by a gradient temperature field, it directly produces low-carbon molten steel at low temperatures, achieving a complete closed-loop carbon cycle. This eliminates the contradiction between high carbon emissions and the difficulty of liquid slag removal in all-hydrogen metallurgy, resolving the aforementioned technical problems in existing steelmaking technologies.

[0006] The technical solution of this invention is: A hydrogen metallurgical steelmaking method based on methanol-to-hydrogen involves the following steps: Methanol is cracked to produce a mixture of H2 and CO; the H2 and CO mixture is used as a reducing agent in a reaction tower to react with injected, ground iron powder, which is then reduced to metallized iron powder at 900℃-1100℃; high-purity hydrogen is prepared by reforming methanol with water and supplied to a plasma generator as a working medium; the metallized iron powder enters the molten pool of the furnace, where ultra-high temperature hydrogen plasma generated by the plasma generator at 3000℃ is injected at high speed into the molten pool, forming a gushing spring-like stirring action to achieve slag-iron separation and complete direct steelmaking.

[0007] The high-temperature exhaust gas generated in the reaction tower is purified and separated, then catalytically synthesized into methanol, and returned to the methanol storage tank for recycling.

[0008] The waste heat from the high-temperature exhaust gas generated in the reaction tower is used to generate electricity through a generator set; the electricity generated by the generator set is used for catalytic synthesis of methanol, methanol cracking, methanol reforming, and plasma generator, achieving self-production and self-use.

[0009] The methanol cracking produces a mixture of approximately 75% H2 and 25% CO as a reducing agent; methanol is reformed with water to produce ≥99.9% high-purity hydrogen.

[0010] The upper part of the reaction tower is a fluidized bed zone, and the lower part is a furnace; the working temperature range of the furnace is 1350-1450℃; the iron powder is first ground and heated to a temperature of 800-900℃, and then sprayed into the fluidized bed zone at high speed. The airflow generates shear force on the ultrafine iron powder, instantly dispersing it and causing a reduction reaction; at the same time, the ultrafine iron powder at a temperature of 900-1100℃ inside the reaction tower undergoes a reduction reaction and falls, which, together with the mixed gas cushion in the fluidized bed zone, prevents the ultrafine iron powder from sticking together.

[0011] The furnace is a molten reduction pool constructed of refractory materials. It is heated by hydrogen plasma, which sprays high-temperature hydrogen plasma above 3000℃ into the pool, creating a gushing phenomenon that replaces mechanical stirring and enhances the slag-steel reaction. Iron oxide scale is added to the pool as a flux to lower the melting point of the slag, and lime is added as a dephosphorizing agent to achieve efficient dephosphorization at a low temperature of 1380-1450℃.

[0012] The molten steel in the molten pool sinks due to its high density, while the slag floats due to its low density. The low-carbon molten steel is discharged to the continuous casting machine through the immersion tap at the bottom of the molten pool. The slag is discharged from the slag outlet between the fluidized bed zone and the furnace and undergoes water quenching treatment.

[0013] This invention produces low-carbon molten steel by controlling the ratio of methanol cracking gas as a reducing agent and hydrogen production, and by adjusting the power of the plasma generator, thereby precisely controlling the carbon content of molten steel to 0.05%-0.3%.

[0014] The high-temperature exhaust gas discharged from the top of the reaction tower contains CO2, unreacted H2, and CO. After dust removal, compression, and desulfurization treatment, the purified high-temperature exhaust gas undergoes a catalytic synthesis reaction within the tower to regenerate methanol, which is then recycled. The methanol recycling rate of this invention is >90%.

[0015] A system for hydrogen metallurgical steelmaking based on methanol-to-hydrogen is provided to implement the aforementioned hydrogen metallurgical steelmaking method. The system includes at least a reaction tower and a methanol cracking unit. The upper part of the reaction tower is a fluidized bed zone, and the lower part is a furnace. The furnace is equipped with a plasma generator. The bottom of the fluidized bed zone is a fluidized bed body, with an iron ore powder injection inlet, a cracked mixed gas inlet, and a high-temperature tail gas outlet at the top. A slag outlet is provided between the fluidized bed zone and the furnace. The high-temperature tail gas is regenerated into formaldehyde through a catalytic synthesis unit and returned to the methanol storage tank. A mixture of hydrogen and carbon monoxide, acting as a reducing agent, enters the fluidized bed zone through the mixed gas inlet and reacts with iron powder injected through the iron ore powder injection inlet. The resulting metallized iron powder falls into the lower furnace through the fluidized bed body. High-purity hydrogen is prepared by methanol and water reforming and supplied to the plasma generator as a working medium. The plasma generator produces hydrogen plasma, and the molten pool utilizes the hydrogen plasma to generate ultra-high temperature jets above 3000°C, forming a spring-like stirring action to achieve slag-iron separation and complete direct steelmaking.

[0016] The iron powder is iron ore raw material that has been ground and heated, and then injected into the fluidized bed zone through the iron ore powder injection port.

[0017] The methanol is reformed with water and then purified to produce 99.9% high-purity hydrogen.

[0018] The upper fluidized bed zone of the reaction tower is connected to the furnace through the fluidized bed body at the bottom of the fluidized bed zone. The channel of the fluidized bed body is composed of baffles of different lengths arranged in a 2:1 ratio. The tops of the long and short baffles are connected as one unit, and both baffles are arranged at a 30° angle to the centerline of the reaction tower. An auxiliary jet guiding device is also provided in the channel. The metallized iron powder generated in the fluidized bed zone falls into the lower molten pool through the fluidized bed body. During the falling process, the auxiliary jet guiding device and the channel baffles work together to form an auxiliary airflow on the inner wall below the baffles, creating a swirling barrier to prevent the high-temperature hot gas from rising from the lower part, thereby maintaining the temperature difference between the upper and lower parts of the reaction tower. At the same time, the inclined channel, combined with the long and short baffle structure, can guide the metallized iron powder to fall smoothly into the molten pool, effectively preventing material accumulation. Key points of this patent application: 1. Methanol cracking mixed gas staged utilization and fully closed-loop gas supply system: Methanol is cracked into a mixture of hydrogen and carbon monoxide as a preliminary reducing agent. Methanol is reformed to produce high-purity hydrogen, which is then plasma-treated and used separately. The high-temperature tail gas at the top of the reaction tower is recovered for methanol synthesis, forming a closed-loop process. 2. Gradient temperature field and low-temperature steelmaking process: The upper fluidized bed zone is kept at a low temperature (900-1100℃) for solid-phase reduction and to prevent sticking. The lower furnace is kept at a low temperature (1380-1450℃), which differs from the traditional 1500+℃. Iron oxide scale is used as a flux to achieve low-temperature liquid slag discharge, directly producing low-carbon steel with a carbon content of 0.05%-0.3%, which can be directly continuously cast. 3. Fluxing and dephosphorizing slag: Iron oxide scale is added to the molten pool as a flux. Industrial solid waste is used to lower the melting point. Low-temperature dephosphorization is carried out in conjunction with lime to achieve good separation of slag and iron at low temperature. 4. Hydrogen plasma jet stirring: The kinetic energy generated by the hydrogen plasma jet is used to stir the molten pool, preventing nozzle clogging and enhancing the reaction.

[0019] This invention is applicable to the direct production of molten low-carbon steel using non-coking coal energy and iron-containing raw materials, and is particularly suitable for achieving near-zero carbon emissions and a short-process manufacturing in steel production. This invention utilizes methanol as a dual carrier of hydrogen and carbon, and through gradient temperature field control, directly produces low-carbon steel at low temperatures, achieving a fully closed-loop carbon cycle. Compared with existing technologies, this invention has advantages such as a fully closed-loop carbon cycle, a short process, low cost, and strong raw material adaptability.

[0020] This invention offers the following advantages: 1. Closed-loop carbon system with near-zero emissions: Carbon elements within the system are recycled using methanol as a carrier. The high-temperature exhaust gas at the top of the reaction tower does not release CO2 into the atmosphere, reducing emissions and protecting the environment. Waste heat can also be used for power generation, enabling self-consumption and reducing electricity consumption. 2. Shortened process: The three high-pollution, high-energy-consuming stages of sintering, coking, and converter processes in the traditional process are eliminated, achieving a one-step process from iron ore powder to molten steel, directly producing steel. 3. Significantly reduced costs: Costs are reduced by approximately 20% compared to the traditional long process. 4. Strong raw material adaptability: It does not rely on high-quality coke and can directly use low-grade iron ore and high-phosphorus iron ore, utilizing industrial solid waste iron oxide scale as a flux, turning waste into treasure. 5. High-end products: It directly produces low-carbon, pure molten steel (C 0.05-0.3%) with extremely low sulfur and phosphorus content, meeting the requirements for high-quality steel. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of an embodiment of the present invention; The diagram is marked as follows: 1. Fluidized bed zone; 2. Furnace; 3. Plasma generator; 4. Iron ore powder injection inlet; 5. Methanol storage tank; 6. Cracking mixed gas inlet; 7. High-temperature tail gas outlet; 8. Slag outlet; 9. Catalytic synthesis unit; 10. Fluidized bed body. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0023] A hydrogen metallurgical steelmaking method based on methanol-to-hydrogen involves the following steps: Methanol is cracked to produce a mixture of H2 and CO; the H2 and CO mixture is used as a reducing agent in a reaction tower to react with injected iron powder, reducing it to metallized iron powder in an environment of 900℃-1100℃; high-purity hydrogen is prepared by reforming methanol with water and supplied to a plasma generator as a working medium; the metallized iron powder enters the molten pool of the furnace, and ultra-high temperature hydrogen plasma above 3000℃ generated by the plasma generator is injected into the molten pool, forming a spring-like stirring to achieve slag-iron separation and complete direct steelmaking.

[0024] The high-temperature exhaust gas generated in the reaction tower is purified and separated, then catalytically synthesized into methanol, and returned to the methanol storage tank for recycling.

[0025] The waste heat from the high-temperature exhaust gas generated in the reaction tower is used to generate electricity through a generator set; the electricity generated by the generator set is used for catalytic synthesis of methanol, methanol cracking, methanol and water reforming, and plasma generator, achieving self-production and self-use.

[0026] The methanol cracking produces a mixture of H2 and CO as a reducing agent; methanol is reformed with water to prepare high-purity hydrogen with a purity of ≥99.9%, which enters the plasma generator.

[0027] The upper part of the reaction tower is a fluidized bed zone 1, and the lower part is a furnace 2; the working temperature range of the furnace is 1350-1450℃; the iron powder is first ground and heated to a temperature of 800-900℃, and then sprayed into the fluidized bed zone at high speed. The airflow generates shear force on the ultrafine iron powder, instantly breaking it up and causing a reduction reaction; at the same time, the ultrafine iron powder at a temperature of 900-1100℃ inside the reaction tower undergoes a reduction reaction and falls down, which, together with the mixed gas cushion in the fluidized bed zone, prevents the ultrafine iron powder from sticking together.

[0028] The furnace is a molten reduction pool constructed of refractory materials. The pool is heated by hydrogen plasma. At a low temperature of 1380-1450℃, the hydrogen plasma generates ultra-high temperature jets of over 3000℃, creating a gushing phenomenon within the pool. This replaces mechanical stirring and enhances the slag-steel reaction. Iron oxide scale is added to the pool as a flux to lower the slag melting point, and lime is added as a dephosphorizing agent to achieve efficient dephosphorization.

[0029] The molten steel in the molten pool sinks due to its high density, while the slag floats due to its low density. The low-carbon molten steel is discharged to the continuous casting machine through the immersion tap at the bottom of the molten pool. The slag is discharged from the slag outlet between the fluidized bed zone 1 and the furnace 2 and undergoes water quenching treatment.

[0030] This invention produces low-carbon molten steel by controlling the ratio of methanol cracking gas as a reducing agent and hydrogen production, and by adjusting the power of the plasma generator, thereby precisely controlling the carbon content of molten steel to 0.05%-0.3%.

[0031] The high-temperature exhaust gas discharged from the top of the reaction tower contains CO2, H2O, unreacted H2 and CO. After dust removal, compression, separation and desulfurization treatment, the purified high-temperature exhaust gas is reacted in the catalytic synthesis unit 9 to regenerate methanol, which is then returned to the methanol storage tank for recycling. The methanol recycling rate of this invention is >90%.

[0032] In this embodiment, the hydrogen metallurgical steelmaking method includes the following steps: S1. Raw material preparation: Grind iron ore powder into ultrafine iron powder; S2. Gas staged preparation: Methanol is cracked into a mixed gas as a reducing agent, methanol is reformed to prepare high-purity hydrogen, and then plasma-ionized; S3. Gradient Temperature Reduction: Ultrafine iron concentrate is reduced to metallized iron powder in the upper fluidized bed zone at 900℃-1100℃; Chemical reactions: Fe2O3 + 3H2 = 2Fe + 3H2O Fe2O3 + 3CO = 2Fe + 3CO2 S4. Low-temperature melting: The reduction product falls into the metallized iron powder and enters the molten pool of the bottom furnace. Under the action of hydrogen plasma at 1380℃-1450℃, iron oxide scale and lime are added to achieve slag-iron separation and produce low-carbon molten steel with a carbon content of 0.05%-0.3%. S5. Carbon cycle: The high-temperature tail gas at the top of the reaction tower is purified, compressed, and catalytically synthesized into methanol.

[0033] A system for hydrogen metallurgical steelmaking based on methanol-to-hydrogen, used to implement the aforementioned hydrogen metallurgical steelmaking method, includes at least a reaction tower and a methanol cracking unit. The upper part of the reaction tower is a fluidized bed zone 1, and the lower part is a furnace 2. The furnace 2 is equipped with a plasma generator 3. The bottom of the fluidized bed zone 1 is a fluidized bed body 10, which is provided with an iron ore powder injection inlet 4, a cracked mixed gas inlet 6, and a high-temperature tail gas outlet 7 at the top. A slag outlet 8 is provided between the fluidized bed zone 1 and the furnace 2. The high-temperature tail gas is regenerated into methanol through a catalytic synthesis unit 9. The alcohol is returned to the methanol storage tank 5. The hydrogen and carbon monoxide mixture is used as a reducing agent and enters the fluidized bed zone 1 through the mixed gas inlet 6 to react with the iron powder injected through the iron ore powder injection inlet 4. The resulting metallized iron powder falls into the lower furnace 2 through the fluidized bed body 10. The methanol and water are reformed to produce high-purity hydrogen, which is supplied to the plasma generator 3 as the working medium. The plasma generator produces hydrogen plasma, and the molten pool uses the hydrogen plasma to generate ultra-high temperature jets above 3000°C, forming a spring-like stirring to achieve slag-iron separation and complete direct steelmaking.

[0034] The iron powder is iron ore raw material that has been ground and heated, and then injected into the fluidized bed zone 1 through iron ore powder injection port 4.

[0035] The methanol is reformed with water and then purified to produce 99.9% high-purity hydrogen.

[0036] The upper fluidized bed zone 1 of the reaction tower is connected to the furnace 2 via a fluidized bed body 10 at the bottom of the fluidized bed zone. The channel of the fluidized bed body 10 is composed of two baffles of different lengths arranged in a 2:1 ratio. The tops of the long and short baffles are connected as one unit, and both baffles are arranged at a 30° angle to the centerline of the reaction tower. An auxiliary jet guiding device is also provided in the channel. The metallized iron powder generated in the fluidized bed zone 1 falls into the lower molten pool through the fluidized bed body 10. During the falling process, the auxiliary jet guiding device and the channel baffles work together to form an auxiliary airflow on the inner wall below the baffles, creating a swirling barrier to prevent the high-temperature hot gas from rising from the lower part, thereby maintaining the temperature difference between the upper and lower parts of the reaction tower. At the same time, the inclined channel, combined with the long and short baffle structure, can guide the metallized iron powder to fall smoothly into the molten pool, effectively preventing material accumulation. In this embodiment, a vertical reaction tower is constructed, 30 meters high and 4-6 meters in inner diameter. The upper part is a fluidized bed zone, and the lower part is a furnace. The molten pool (melting pool) is lined with magnesium-calcium bricks, and four 1000kW hydrogen plasma torches are installed. Local ultra-high temperature hydrogen plasma jets above 3000 ℃ are injected into the molten pool to maintain the furnace temperature and carry out the final reduction reaction.

[0037] Process: Raw material: Iron ore powder (TFe 62%) ground into ultrafine iron powder; Methanol flow rate: 5t / h (4t / h to produce mixed gas for use as a reducing agent, 1t / h to produce pure hydrogen). Reduction: Ultrafine iron powder undergoes a reduction reaction in a fluidized bed at around 1000℃, achieving a metallization rate >92%; Melting process: The temperature of the molten pool is controlled at 1380-1450℃; iron oxide scale with an iron content of 70% (accounting for about 10% of the slag) and active lime are added; Results: The produced molten steel had a carbon content of 0.05-0.3%, a phosphorus content of <0.01%, a sulfur content of <0.005%, and good slag fluidity; High-temperature exhaust gas: CO2 is captured and methanol is synthesized, with a recycling rate of >90%.

[0038] Alternatives to the present invention: 1. Alternative reducing agents: In addition to methanol cracked gas, natural gas reformed gas or pure hydrogen can also be used as the reducing agent in the upper part of the system. However, methanol is the best because it is easy to store and transport as a liquid and contains carbon and oxygen.

[0039] 2. Flux Substitution: Besides iron oxide scale, other iron oxides, such as rolled steel scale and Fe2O3 powder, can be used as fluxes. In addition to lime (CaO), other basic fluxes, such as fluorite (CaF2), can also be used to help lower the melting point, but lime combined with iron oxide scale is most effective for dephosphorization.

[0040] 3. Heat source substitution: Hydrogen plasma torches can be replaced by other electric heating methods, such as electric arc heating, but hydrogen plasma has the triple effect of heat + reducing agent + stirring, and cannot be completely replaced.

[0041] 4. Temperature parameter substitution: The upper reduction temperature can be adjusted between 850-1150℃, and the lower melting temperature can be adjusted between 1350-1500℃, but 1380-1450℃ is the best window to balance energy consumption and fluidity.

[0042] Terminology Explanation: Methanol cracking: refers to the direct decomposition of methanol (CH3OH) into 75% hydrogen (H2) and 25% carbon monoxide (CO) gas under the action of a catalyst; Methanol reforming: refers to the reaction of methanol (CH3OH) with water under the action of a catalyst to produce gas, which is then purified by PSA to produce high-purity hydrogen (H2). Gradient temperature field: refers to the state in which the temperature is lower in the upper fluidized bed zone of the reactor (900-1100℃) and higher in the lower furnace zone (1380-1450℃), with the temperature showing a gradient distribution.

Claims

1. A hydrogen metallurgical steelmaking method based on methanol-to-hydrogen production, characterized in that: Methanol is cracked to produce a mixture of H2 and CO. The H2 and CO mixture is used as a reducing agent to enter the reaction tower and react with the injected and ground iron powder. It is reduced to metallized iron powder in an environment of 900℃-1100℃. Methanol is reformed with water to produce high-purity hydrogen, which is supplied to the plasma generator as a working medium. The metallized iron powder enters the molten pool of the furnace. The 3000℃ ultra-high temperature hydrogen plasma generated by the plasma generator is injected into the molten pool at high speed, forming a spring-like stirring to achieve slag-iron separation and complete direct steelmaking.

2. The hydrogen metallurgical steelmaking method based on methanol-to-hydrogen according to claim 1, characterized in that: The high-temperature exhaust gas generated in the reaction tower is purified and separated, then catalytically synthesized into methanol, and returned to the methanol storage tank for recycling.

3. The hydrogen metallurgical steelmaking method based on methanol-to-hydrogen according to claim 1, characterized in that: The waste heat from the high-temperature exhaust gas generated in the reaction tower is used to generate electricity through a generator set; the electricity generated by the generator set is used for catalytic synthesis of methanol, methanol cracking, methanol reforming, and plasma generator, achieving self-production and self-use.

4. A hydrogen metallurgical steelmaking method based on methanol-to-hydrogen according to claim 1 or 2, characterized in that: The methanol cracking produces a mixture of 75% H2 and 25% CO as a reducing agent; methanol is reformed with water to produce ≥99.9% high-purity hydrogen.

5. A hydrogen metallurgical steelmaking method based on methanol-to-hydrogen according to claim 1 or 2, characterized in that: The upper part of the reaction tower is a fluidized bed zone (1), and the lower part is a furnace (2); the working temperature range of the furnace is 1350-1450℃; the iron powder is first ground and heated to a temperature of 800-900℃, and then sprayed into the fluidized bed zone at high speed. The airflow generates shear force on the ultrafine iron powder, which is instantly dispersed and undergoes a reduction reaction; at the same time, the ultrafine iron powder at a temperature of 900-1100℃ inside the reaction tower undergoes a reduction reaction and falls down, which, together with the mixed gas cushion of the fluidized bed zone, prevents the ultrafine iron powder from sticking together.

6. A hydrogen metallurgical steelmaking method based on methanol-to-hydrogen according to claim 1 or 2, characterized in that: The furnace is a molten reduction pool constructed of refractory materials. It is heated by hydrogen plasma, which sprays high-temperature hydrogen plasma above 3000℃ into the pool, creating a gushing phenomenon that replaces mechanical stirring and enhances the slag-steel reaction. Iron oxide scale is added to the pool as a flux to lower the melting point of the slag, and lime is added as a dephosphorizing agent to achieve efficient dephosphorization at a low temperature of 1380-1450℃.

7. A hydrogen metallurgical steelmaking method based on methanol-to-hydrogen according to claim 1 or 2, characterized in that: The molten steel in the molten pool sinks due to its high density, while the slag floats due to its low density. The low-carbon molten steel is discharged to the continuous casting machine through the immersion tap at the bottom of the molten pool. The slag is discharged from the slag outlet between the fluidized bed zone (1) and the furnace (2) and is subjected to water quenching.

8. A hydrogen metallurgical steelmaking method based on methanol-to-hydrogen according to claim 1 or 2, characterized in that: By controlling the ratio of methanol cracking gas used as a reducing agent and for hydrogen production, and adjusting the power of the plasma generator, the carbon content of molten steel can be precisely controlled between 0.05% and 0.3%, thus producing low-carbon molten steel.

9. A system for hydrogen metallurgical steelmaking based on methanol-to-hydrogen, used to implement the hydrogen metallurgical steelmaking method according to any one of claims 1-8, characterized in that: The system includes at least a reaction tower and a methanol cracking unit. The upper part of the reaction tower is a fluidized bed zone (1), and the lower part is a furnace (2). The furnace (2) is equipped with a plasma generator (3). The bottom of the fluidized bed zone (1) is a fluidized bed body (10), and it is equipped with an iron ore powder injection inlet (4), a cracked mixed gas inlet (6), and a high-temperature tail gas outlet (7) at the top. A slag outlet (8) is provided between the fluidized bed zone (1) and the furnace (2). The high-temperature tail gas is regenerated into methanol through a catalytic synthesis unit (9) and returned to the methanol storage tank (5). The hydrogen and carbon monoxide mixture is used as a reducing agent to enter the fluidized bed zone (1) through the mixed gas inlet (6) and react with the iron powder injected through the iron ore powder injection inlet (4). The resulting metallized iron powder falls into the lower furnace (2) through the fluidized bed body (10). High-purity hydrogen is prepared by reforming methanol and water and supplied to the plasma generator (3) as the working medium. The plasma generator generates hydrogen plasma, and the molten pool uses hydrogen plasma to generate ultra-high temperature jets above 3000℃ to form a spring-like stirring, realize slag-iron separation, and complete direct steelmaking.

10. A system for hydrogen metallurgical steelmaking based on methanol-to-hydrogen according to claim 9, characterized in that: The upper fluidized bed zone (1) of the reaction tower and the furnace (2) are connected through the fluidized bed body (10) at the bottom of the fluidized bed zone. The channel of the fluidized bed body (10) is composed of a long and a short baffle with a length ratio of 2:

1. The tops of the long and short baffles are connected as one unit, and both the long and short baffles are arranged at a 30° angle with the center line of the reaction tower. An auxiliary jet guide device is also provided in the channel. The metallized iron powder generated in the fluidized bed zone (1) falls into the lower molten pool through the fluidized bed body (10). During the falling process, the auxiliary jet guide device and the channel baffle work together to form an auxiliary airflow on the inner wall below the baffle, and construct a swirling barrier to block the high temperature hot gas from rising from the bottom, thereby maintaining the temperature difference between the upper and lower parts of the reaction tower. At the same time, the inclined channel, in combination with the long and short baffle structure, can guide the metallized iron powder to fall smoothly into the molten pool, effectively preventing material accumulation.

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