A method for producing iron by a high-pressure shaft furnace direct-connected gasifier by a staged reduction

Abstract

This invention discloses a segmented reduction ironmaking method for a high-pressure vertical shaft furnace directly connected to a gasifier, belonging to the field of reduction ironmaking technology. The method includes: recovering part of the heat from the syngas generated by the high-pressure gasifier through a radiant waste boiler and removing dust at high temperature, then directly introducing it into the upper reducing gas inlet of the high-pressure vertical shaft furnace; adding pellets to the top of the shaft furnace through a pressure-changing lock hopper device; maintaining the shaft furnace operating pressure ≥1 MPaG; introducing a high-CO atmosphere of 500~850℃ for pre-reduction in the upper part; and introducing a high-H2 atmosphere of 810~1050℃ after conversion, decarburization, and desulfurization treatment in the lower part for final reduction. Alternatively, a second method can be used: introducing high-temperature, high-H2 reducing gas in the lower part and high-temperature gas from oxygen injection combustion at the top of the furnace for preheating and pre-reduction. This invention achieves direct connection between the high-pressure gasifier and the high-pressure vertical shaft furnace, eliminating the need for pressure and temperature reduction. The segmented reduction conforms to thermodynamic laws, improves the utilization rate and energy efficiency of the reducing gas, and reduces operating costs.

Description

Technical Field

[0001] This invention relates to the field of reduction ironmaking technology, and in particular to a segmented reduction ironmaking method for a high-pressure vertical furnace directly connected to a gasifier. Background Technology

[0002] Currently, iron smelting worldwide primarily relies on traditional blast furnace ironmaking technology. While blast furnace ironmaking technology boasts advantages such as high output, high efficiency, and strong adaptability to iron ore grades, its long-process steelmaking process, which utilizes coke, sinter, or pellets to produce molten iron, suffers from significant drawbacks under increasingly stringent environmental requirements: a lengthy and complex process, high dependence on scarce coking coal, high energy consumption and carbon emission intensity, and a large variety and volume of pollutants. It also suffers from poor production flexibility and high investment and maintenance costs. In contrast, the short-process technology of producing sponge iron using a gas-based vertical shaft furnace direct reduction method offers significant economic and environmental benefits due to the elimination of coking and sintering processes and reduced waste emissions, making it the future development direction.

[0003] Gas-based vertical shaft reduction (VCR) uses reducing gases (CO and H2) as reducing agents to reduce ore to obtain solid metallic iron at temperatures below the softening temperature of lump or pellet ore. MIDREX and HYL are representative companies of VCR technology, which uses natural gas reforming as the reducing gas and low-pressure vertical shaft furnaces for sponge iron production. Due to the scarcity of natural gas resources and the abundance of coal resources in my country, coal gasification syngas is more suitable as the reducing gas. High-pressure fluidized bed gasification technology can efficiently convert pulverized coal or biomass into syngas (CO+H2≈90%, CO2+H2O≈10%, H2 / (CO+H2)≈1:3, carbon conversion rate>99%), representing an advanced gasification technology.

[0004] However, high-pressure gasification technology and gas-based vertical shaft furnaces suffer from mismatches in both atmosphere and pressure: the high CO2 content in the reducing gas exiting the gasifier leads to insufficient reduction of sponge iron; simultaneously, high-pressure gasifiers (>3.0 MPa) cannot be directly connected to low-pressure gas-based vertical shaft furnaces (pressure approximately 0.2 MPa~0.7 MPa). Existing technologies such as CN1141402C and CN101597663B typically require the high-temperature syngas to be cooled to around 200°C, undergoing conversion and decarbonization, before being heated to around 900°C in a reheater before entering the vertical shaft furnace. This results in low energy utilization efficiency due to the initial cooling followed by reheating. Furthermore, the low outlet pressure of the syngas from existing low-pressure vertical shaft furnaces makes it unsuitable for direct use in downstream chemical synthesis, requiring further compression, which is economically unfeasible. Moreover, the reducing gas composition and temperature in existing vertical shaft furnaces have not been optimized in stages according to the thermodynamic laws of iron oxide reduction, failing to fully utilize the respective reducing capacities of H2 and CO. Summary of the Invention

[0005] The purpose of this invention is to solve the problem that high-pressure gasifiers and gas-based vertical shaft furnaces cannot be directly connected in the prior art, overcome the mismatch in atmosphere, pressure and temperature, and provide a segmented reduction ironmaking method for direct connection of high-pressure vertical shaft furnace to gasifier, so that the vertical shaft furnace can operate above 1MPaG and be directly connected to the high-pressure gasifier. At the same time, the optimal configuration of reducing atmosphere and temperature is achieved through segmented gas intake, thereby improving the utilization efficiency of reducing gas and the economic efficiency of the process.

[0006] To achieve the above objectives, the present invention provides a segmented reduction ironmaking method for a high-pressure vertical shaft furnace directly connected to a gasifier, comprising the following steps: (1) A high-pressure gasifier with an operating pressure ≥1MPaG is used to carry out gasification reaction with gasification feedstock and gasification agent to produce syngas; (2) The temperature of the synthesis gas is cooled to 500~850℃ and after high-temperature dust removal, it is directly introduced into the upper reducing gas inlet of the high-pressure vertical furnace. The atmosphere of the upper reducing gas is CO+H2≈90%, CO2+H2O≈10%, H2 / (CO+H2)≈0.3 by volume. (3) After passing through the atmospheric pressure storage silo, the variable pressure lock hopper and the buffer silo, the pellets enter the furnace from the top of the high pressure vertical furnace; (4) At the top of the high-pressure vertical furnace, the pellets are preheated with reducing gas at 500~850℃ and Fe2O3 is reduced to FeO; (5) After purification, conversion, decarburization and desulfurization, the top gas of the high-pressure vertical furnace is reduced gas with a volume ratio of CO+H2>90%, CO2+H2O<5%, and H2 / (CO+H2)>0.5. Part of the reduced gas is introduced into the cooling zone of the lower cone section of the vertical furnace to cool the sponge iron products. The other part of the reduced gas is heated to 810~1050℃ and then introduced from the reduced gas inlet at the bottom of the vertical furnace to reduce FeO to Fe. (6) Cool the reduced sponge iron to a temperature of <600℃, and after discharge, pass through a buffer bin, a transformer lock hopper, and a melting furnace in sequence to produce molten iron and slag.

[0007] Optionally, the operating pressure of the high-pressure gasifier is 3~6.5 MPaG, and the operating pressure of the high-pressure vertical furnace is 1~4 MPaG.

[0008] Optionally, in step (2), the high-temperature dust removal is carried out using a high-temperature cyclone dust collector, and the dust content of the syngas after dust removal is ≤15g / Nm³. 3 .

[0009] Optionally, in step (5), the temperature of the top gas of the high-pressure vertical furnace is 300~500℃.

[0010] Secondly, the present invention also provides another method for staged reduction ironmaking using a high-pressure vertical furnace directly connected to a gasifier, comprising the following steps: (1) A high-pressure gasifier with an operating pressure ≥1MPaG is used to carry out gasification reaction with gasification feedstock and gasification agent to produce syngas; (2) The temperature of the synthesis gas is cooled to 500~850℃ and after high-temperature dust removal, it is purified, converted, decarbonized and desulfurized in sequence to obtain a reducing gas with a volume ratio of CO+H2>90%, CO2+H2O<5%, and H2 / (CO+H2)>0.5. Part of the reducing gas is introduced into the cooling zone of the lower cone section of the high-pressure vertical furnace to cool the sponge iron product, and the other part of the reducing gas is heated to 810~1050℃ and then introduced from the reducing gas inlet at the bottom of the vertical furnace to reduce Fe3O4 to Fe. (3) After passing through the atmospheric pressure storage silo, the variable pressure lock hopper and the buffer silo, the pellets enter the furnace from the top of the high pressure vertical furnace; (4) After the top gas of the high-pressure vertical furnace is drawn out, oxygen is injected into it for combustion to raise the gas temperature to 500~1050℃. Then it is introduced from the reducing gas inlet at the top of the vertical furnace to preheat the pellets and reduce Fe2O3 to Fe3O4. (5) Cool the reduced sponge iron to a temperature of <600℃, and after discharge, pass through a buffer bin, a transformer lock hopper, and a melting furnace in sequence to produce molten iron and slag.

[0011] Optionally, in step (4), the CO+H2 content in the top gas after oxygen injection combustion is lower than that before combustion, while the CO2+H2O content increases. The preheating and pre-reduction are completed by utilizing the characteristic that Fe2O3 is easily reduced.

[0012] Optionally, the gasification feedstock is coal or biomass, the gasifying agent is oxygen and / or water vapor, and the gasification reaction temperature is 1200~1500℃.

[0013] Optionally, the top gas from the vertical shaft furnace, after undergoing conversion, decarbonization, and desulfurization, is used for downstream chemical synthesis, including coal-to-methanol, coal-to-ethylene glycol, or coal-to-olefins.

[0014] Optionally, the pellets have a TFe content of >65% and a particle size range of 10~20mm.

[0015] In this invention, the reduction of Fe2O3 to Fe is carried out in steps, wherein Fe2O3 is first reduced to Fe3O4, then Fe3O4 is reduced to FeO, and finally reduced to Fe, as shown by the fork curve ( Figure 3It can be seen that Fe2O3 is readily reduced to Fe3O4 by CO and H2, while the reduction of Fe3O4 to FeO is relatively difficult, requiring higher concentrations of CO or H2. The reduction of FeO to Fe is the most difficult, requiring higher concentrations of CO and H2. For example, at 700℃, the equilibrium concentration of CO for the reduction of Fe3O4 to FeO only needs to be about 35% (above this concentration is sufficient to complete the reduction reaction), but for the reduction of FeO to Fe, the equilibrium concentration of CO needs to reach 60%. Furthermore, in the most difficult step of reducing FeO to Fe, CO has a stronger reducing power than H2 at low temperatures. For example, at 700℃, the equilibrium concentration of CO is 60%, and the equilibrium concentration of H2 is 70% (i.e., a higher concentration of H2 is needed to complete the reduction reaction). At 1100℃, the equilibrium concentration of CO is 73.8%, and the equilibrium concentration of H2 is 57.4%. According to the thermodynamic "fork curve" law of iron oxide reduction, at low temperatures (<810℃), CO has a stronger reducing power than H2, while at high temperatures (>810℃), H2 has a stronger reducing power than CO. The first embodiment of the present invention introduces a high CO atmosphere of 500℃~850℃ in the upper part for pre-reduction and a high H2 atmosphere of 810℃~1050℃ in the lower part for final reduction. This fully conforms to the thermodynamic laws and greatly improves the comprehensive utilization rate of reducing gas from about 30% in the traditional process, thereby reducing the amount of circulating gas and heating energy consumption.

[0016] Compared with the prior art, the present invention has at least the following advantages: (1) This invention combines coal gasification / biomass gasification with direct reduction ironmaking process, which not only promotes the application of gas-based direct reduction short-process ironmaking technology, but also broadens the application of syngas produced by gasification. High-pressure fluidized bed gasification technology is the most advanced gasification technology at present, and its carbon conversion rate is higher than that of fixed bed and fluidized bed technology. Vertical shaft furnace is the most successful direct reduction iron technology with the largest market share. The combination of the two best technologies is conducive to the development and promotion of the technology.

[0017] (2) The present invention adopts a two-stage gas intake method in the vertical furnace, and respectively adopts high CO medium and low temperature reducing gas in the upper stage and high H2 high temperature reducing gas in the lower stage (Scheme 1), or high CO2 preheating gas in the upper stage and high H2 high temperature reducing gas in the lower stage (Scheme 2). This realizes the segmented reduction in the vertical furnace, the whole reduction process conforms to the thermodynamic optimal reduction zone, improves the gas utilization rate of reducing gas, reduces the total amount of circulating gas, and improves the economy of the vertical furnace.

[0018] (3) The present invention adopts a direct connection between a high-pressure vertical furnace and a high-pressure gasifier. By using a variable pressure lock hopper feeding device, the problem of pressure mismatch between the high-pressure gasifier and the existing low-pressure vertical furnace is solved. At the same time, by using the reduction method in the upper and lower sections, the amount of gas passing through the heating furnace is reduced, thereby reducing the overall energy consumption of the process.

[0019] (4) This invention improves the overall utilization efficiency of reducing gas. Since the gas-based reduction reaction is a reversible reaction, the general gas utilization rate is about 30%, that is, more than half of the effective gas (CO+H2) after passing through the vertical furnace is still not used. In this technical solution, since the syngas pressure is high, it can be used for chemical production after conversion, purification and other processes (subsequent chemical processes require high pressure), which can significantly improve the economic efficiency of the technology. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the process flow for Scheme 1 of the present invention.

[0021] Figure 2 This is a schematic diagram of the process flow for Scheme 2 of the present invention.

[0022] Figure 3 The thermodynamic "fork curve" pattern of iron oxide reduction. Detailed Implementation To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0023] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be used interchangeably where appropriate to understand the embodiments of the invention described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a product or device comprising a series of units is not necessarily limited to those explicitly listed, but may include other units not explicitly listed or inherent to such product or device.

[0024] In this invention, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing the invention and its embodiments, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to be constructed and operated in a specific orientation.

[0025] Furthermore, in addition to indicating direction or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in certain situations to indicate a dependency or connection. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0026] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linking," and "socketing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; 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, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0028] Example 1 (using Scheme 1) As attached Figure 1 As shown, a high-pressure vertical shaft furnace with an annual production capacity of 1 million tons of sponge iron uses an effective gas output of 90,000 Nm³ per hour. 3 A high-pressure pulverized coal gasification furnace with a capacity of / h (CO+H2). High-pressure oxygen is obtained from the air separation unit, with an oxygen content of approximately 19000 Nm³. 3 The coal is crushed, ground, and screened to obtain pulverized coal (particle size requirement: 5-90μm particles with a mass fraction of over 90%, moisture content controlled at 2-5%), with a coal yield of approximately 52 t / h. Simultaneously, the coal is injected into the furnace through gasification burners at the top of the gasifier, where incomplete combustion of carbon occurs, generating crude syngas primarily composed of CO and H2. The syngas composition is: CO: 65%, H2: 25%, CO2: 6%, H2O: 3%, N2: 1%, temperature 1350℃, pressure 4.0 MPaG, and gas flow rate 100,000 Nm³. 3 / h.

[0029] High-temperature syngas and molten ash enter the radiant waste boiler from the gasifier. The radiant waste boiler absorbs heat through a water-cooled screen, reducing the syngas temperature to 850℃. The ash falls into the bottom slag pool. The dust content of the cooled syngas is approximately 150 g / Nm³. 3 After passing through the waste boiler, the dust enters a high-temperature cyclone dust collector, where the dust content is further reduced to 15g / Nm³. 3 The temperature is reduced to 800℃ and the pressure is reduced to 3.8 MPaG, and the gas is directly introduced into the reducing gas inlet at the top of the vertical furnace.

[0030] The feed rate of pellets at the top of the vertical shaft furnace is approximately 185 t / h, preferably with TFe > 65% and a particle size range of 10~20 mm, of which particles smaller than 5 mm cannot exceed 5%. The pellets first enter the atmospheric pressure storage silo, and then enter the variable pressure lock hopper through a valve control. After that, the valve above the lock hopper is closed to the pellet storage silo, and the lock hopper is pressurized to the same pressure as the vertical shaft furnace. Then the valve below the lock hopper is opened to the pellet buffer silo. At this time, both the lock hopper and the buffer silo are under high pressure. The pellets enter the pellet buffer silo under the action of gravity, and then enter the vertical shaft furnace through the feed pipe.

[0031] The pellets enter the vertical shaft furnace and first pass through the first reduction section. The upper reducing gas temperature is 800℃, CO+H2≈90%, H2 / (CO+H2)≈0.3. Fe2O3 in the pellets is reduced to FeO, and the temperature is raised to 800℃. Then, they enter the second reduction section, where high-H2 reducing gas (CO+H2>90%, H2 / (CO+H2)>0.5) that has undergone conversion, decarburization, and desulfurization is introduced from the bottom. FeO in the pellets is reduced to Fe, and the temperature is raised to 1050℃. The fully reduced sponge iron (metallization rate>93%) has an hourly sponge iron production rate of 130 t / h.

[0032] The sponge iron is cooled down to 550°C by cooling gas, and then discharged into the DRI buffer bin through a rotary discharge valve. After being depressurized to atmospheric pressure by a pressure-reducing lock hopper, the high-temperature sponge iron falls into the melting and separation electric furnace under gravity, achieving hot delivery and reducing the power consumption of the melting and separation electric furnace. Then, the melting and separation electric furnace is energized to melt the sponge iron, and the molten iron and slag are separated under gravity.

[0033] The top gas of the vertical shaft furnace is the tail gas after the reduction of iron ore inside the furnace, with a volume of approximately 230,000 Nm³. 3 / h, composition: CO: 20%, H2: 42%, CO2: 11%, H2O: 24%, N2: 3%, temperature 450℃, 30,000 Nm³ of gas discharged from the furnace is sent out. 3 The gas volume is approximately 130,000 Nm³ / h, used in the pelletizing process. The remaining gas undergoes a shift conversion process to completely convert CO to H₂. CO₂ and H₂O are then removed from the converted gas, along with a small amount of H₂S. 3 The gas concentration is 0.3% CO, 93.7% H2, 1% CO2, 0.05% H2O, and 5% N2 per hour. Part of the gas is introduced into the furnace bottom for cooling, part into the center of the furnace top to increase the intermediate reducing gas, and the remaining gas is heated to 1050°C in a heating furnace before being introduced into the reducing gas inlet at the bottom of the vertical furnace.

[0034] Example 2 (using Scheme 2) As attached Figure 2 As shown, a high-pressure vertical shaft furnace with an annual production capacity of 1 million tons of sponge iron has a capacity of 220,000 Nm³. 3The reducing gas after decarburization is circulated at a rate of / h and enters the vertical shaft furnace through the lower air inlet. The atmosphere is CO: 15%, H2: 75%, CO2: 2%, H2O: 3%, N2: 5%, temperature 1050℃, and pressure 3.8 MPaG.

[0035] The top gas of the vertical shaft furnace is the tail gas after the reduction of iron ore inside the furnace, with a volume of approximately 230,000 Nm³. 3 / h, composition: CO: 10%, H2: 48%, CO2: 7%, H2O: 30%, N2: 5%, temperature 450℃, 30,000 Nm³ of gas discharged from the furnace is sent out. 3 / h is used for the pelletizing process, with 190,000 Nm remaining. 3 / h furnace top gas recirculation, plus 10,000 Nm 3 After the gas is extracted, it is sent to the combustion furnace to add O2 for combustion and increase the gas temperature. The composition of the gas entering the furnace is CO: 6%, H2: 28%, CO2: 11%, H2O: 50%, N2: 5%, and the temperature is 1050℃. It is introduced from the reducing gas inlet at the top of the vertical furnace to reduce Fe2O3 to Fe3O4 and preheat the ore.

[0036] The lower reducing gas uses high-H2 reducing gas that has undergone conversion, decarbonization, and desulfurization and is heated to 1050℃ to complete the final reduction of FeO→Fe. The remaining processes are similar to those in Example 1. This example fully utilizes the characteristic that Fe2O3 is easily reduced by using low-quality combustion top gas for pre-reduction, further improving the overall thermal efficiency.

[0037] In summary, the method provided by this invention can be directly applied to newly built or renovated coal-based / biomass-based gas-based vertical shaft furnace direct reduction ironmaking units, and is particularly suitable for steel-chemical integrated enterprises that co-produce with large-scale high-pressure fluidized bed gasifiers. Through this invention, efficient cascade utilization of syngas can be achieved, significantly reducing energy consumption and carbon emissions in direct reduced iron production, and it has broad prospects for industrial application.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A segmented reduction ironmaking method using a high-pressure vertical shaft furnace directly connected to a gasifier, characterized in that, Includes the following steps: (1) A high-pressure gasifier with an operating pressure ≥1MPaG is used to carry out gasification reaction with gasification feedstock and gasification agent to produce syngas; (2) The temperature of the synthesis gas is cooled to 500~850℃ and after high-temperature dust removal, it is directly introduced into the upper reducing gas inlet of the high-pressure vertical furnace. The atmosphere of the upper reducing gas is CO+H2≈90%, CO2+H2O≈10%, H2 / (CO+H2)≈0.3 by volume. (3) After passing through the atmospheric pressure storage silo, the variable pressure lock hopper and the buffer silo, the pellets enter the furnace from the top of the high pressure vertical furnace; (4) At the top of the high-pressure vertical furnace, the pellets are preheated with reducing gas at 500~850℃ and Fe2O3 is reduced to FeO; (5) After purification, conversion, decarburization and desulfurization, the top gas of the high-pressure vertical furnace is reduced gas with a volume ratio of CO+H2>90%, CO2+H2O<5%, and H2 / (CO+H2)>0.

5. Part of the reduced gas is introduced into the cooling zone of the lower cone section of the vertical furnace to cool the sponge iron products. The other part of the reduced gas is heated to 810~1050℃ and then introduced from the reduced gas inlet at the bottom of the vertical furnace to reduce FeO to Fe. (6) Cool the reduced sponge iron to a temperature of <600℃, and after discharge, pass through a buffer bin, a transformer lock hopper, and a melting furnace in sequence to produce molten iron and slag.

2. The segmented reduction ironmaking method of a high-pressure vertical furnace directly connected to a gasifier according to claim 1, characterized in that, The operating pressure of the high-pressure gasifier is 3~6.5MPaG, and the operating pressure of the high-pressure vertical furnace is 1~4MPaG.

3. The segmented reduction ironmaking method of a high-pressure vertical furnace directly connected to a gasifier according to claim 1, characterized in that, In step (2), the high-temperature dust removal is carried out using a high-temperature cyclone dust collector, and the dust content of the syngas after dust removal is ≤15g / Nm³. 3 .

4. The segmented reduction ironmaking method of a high-pressure vertical furnace directly connected to a gasifier according to claim 1, characterized in that, In step (5), the temperature of the top gas of the high-pressure vertical furnace is 300~500℃.

5. A segmented reduction ironmaking method for a high-pressure vertical shaft furnace directly connected to a gasifier, characterized in that, Includes the following steps: (1) A high-pressure gasifier with an operating pressure ≥1MPaG is used to carry out gasification reaction with gasification feedstock and gasification agent to produce syngas; (2) The temperature of the synthesis gas is cooled to 500~850℃ and after high-temperature dust removal, it is purified, converted, decarbonized and desulfurized in sequence to obtain a reducing gas with a volume ratio of CO+H2>90%, CO2+H2O<5%, and H2 / (CO+H2)>0.

5. Part of the reducing gas is introduced into the cooling zone of the lower cone section of the high-pressure vertical furnace to cool the sponge iron product, and the other part of the reducing gas is heated to 810~1050℃ and then introduced from the reducing gas inlet at the bottom of the vertical furnace to reduce Fe3O4 to Fe. (3) After passing through the atmospheric pressure storage silo, the variable pressure lock hopper and the buffer silo, the pellets enter the furnace from the top of the high pressure vertical furnace; (4) After the top gas of the high-pressure vertical furnace is drawn out, oxygen is injected into it for combustion to raise the gas temperature to 500~1050℃. Then it is introduced from the reducing gas inlet at the top of the vertical furnace to preheat the pellets and reduce Fe2O3 to Fe3O4. (5) Cool the reduced sponge iron to a temperature of <600℃, and after discharge, pass through a buffer bin, a transformer lock hopper, and a melting furnace in sequence to produce molten iron and slag.

6. The segmented reduction ironmaking method of a high-pressure vertical furnace directly connected to a gasifier according to claim 5, characterized in that, In step (4), the CO+H2 content in the furnace top gas after oxygen injection combustion is lower than that before combustion, while the CO2+H2O content increases. The preheating and pre-reduction are completed by utilizing the characteristic that Fe2O3 is easily reduced.

7. A segmented reduction ironmaking method for a high-pressure vertical shaft furnace directly connected to a gasifier, as described in claim 1 or 5, characterized in that, The gasification feedstock is coal or biomass, the gasification agent is oxygen and / or water vapor, and the gasification reaction temperature is 1200~1500℃.

8. A segmented reduction ironmaking method for a high-pressure vertical furnace directly connected to a gasifier, as described in claim 1 or 5, characterized in that, The top gas from the vertical shaft furnace is converted, decarbonized, and desulfurized before being used for downstream chemical synthesis, including coal-to-methanol, coal-to-ethylene glycol, or coal-to-olefins.

9. A segmented reduction ironmaking method for a high-pressure vertical shaft furnace directly connected to a gasifier, as described in claim 1 or 5, characterized in that, The pellets have a TFe content of >65% and a particle size range of 10~20mm.

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