Device and process for reducing ironmaking by using high-temperature synthesis gas prepared by reforming coke oven gas and CO2

Abstract

The invention provides a device and a process for reducing ironmaking by high-temperature synthesis gas prepared by reforming coke oven gas and CO2, and belongs to the technical field of energy and chemical industry. The device comprises a reforming reactor which is used for enabling CH4 and CO2 in coke oven gas to be subjected to dry reforming reaction to generate high-temperature reducing gas mainly comprising CO and H2; and the high-temperature reduction ironmaking furnace is used for enabling the high-temperature reducing gas obtained by the reforming reactor to be in countercurrent contact with the iron ore particles added from top to bottom to complete solid-state direct reduction reaction so as to generate direct reduction iron. According to the device and the process, efficient conversion of CO2 and efficient resource utilization of coke oven gas can be achieved at the same time, generated high-temperature reducing gas carries sensible heat to provide energy for the iron reduction reaction, the external energy supply requirement can be remarkably lowered, the reaction can be conducted more sufficiently, and the energy consumption is reduced. And carbon emission and energy consumption of direct reduction iron can be greatly reduced through tail gas recovery and heat cyclic utilization.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of energy and chemical industry, in particular to a device and process for reducing iron by reforming coke oven gas and CO2 to produce high-temperature synthesis gas. BACKGROUND

[0002] China's proven recoverable coal reserves rank third in the world, and coal production ranks first in the world. Rational utilization of coal resources and improvement of coal utilization rate have profound economic and strategic significance for ensuring the sustainable, healthy and stable development of China's economy, especially in the current competition among major powers. Among them, strengthening the development of clean and efficient comprehensive utilization technology of coal, expanding the industrial production chain of coal downstream chemicals, and building a new type of coal chemical industry that is compatible with the environment and synergistically developed are important measures to improve the level of coal utilization, reduce carbon emissions and increase efficiency. It is also an inevitable choice to realize the transformation, leap-forward development and sustainable development of China's coal chemical industry.

[0003] In view of the current situation of large-scale discharge of coke oven gas in the coking industry and large-scale discharge of CO2 in the coal-fired, steelmaking and coal chemical industries, as well as the shortage of fossil resources, the carbon-hydrogen complementation is formed according to the characteristics of coke oven gas (CH4, H2) and carbon-rich (CO2) emission gas. The catalytic reforming technology under complex atmosphere is adopted to make CO2 and CH4 in coke oven gas react and convert into high-temperature reducing gas (CO+H2) for subsequent direct reduction of iron. The large amount of sensible heat carried by the reducing gas can provide energy for the reduction reaction, reducing the burden of external heating. At the same time, water resources can be saved, and CO2 emissions can be reduced, which has good economic, environmental and social benefits. Considering the implementation of China's double carbon strategy and the collection of carbon emission tax in the future, this technology shows great economic advantage.

[0004] Direct reduced iron (DRI) is iron ore directly reduced in solid state, which can be used as pure raw material for smelting high-quality steel and special steel, and can also be used as iron-containing raw material for casting, ferroalloy, powder metallurgy and other processes. This process does not use coke for ironmaking, and uses iron ore particles instead of sintered ore, which is a new ironmaking process with high quality, low consumption and low pollution, belongs to short process ironmaking, and is one of the research directions encouraged by the state and one of the frontiers of world steel metallurgy. Compared with hydrogen reduction of iron, the process of CO in synthesis gas for reduction of iron is an exothermic process, so it can alleviate the large amount of heat absorption in the endothermic process of reduction, and has unique advantages. However, since the dry reforming reaction is a strong endothermic process, and hydrogen reduction of iron also requires a large amount of heat, there is currently no reliable device and method for efficient coupling and reaction of the above two processes. SUMMARY

[0005] In order to solve at least one aspect of the above problems and defects in the prior art, embodiments of the present application provide a device and process for reducing iron by reforming coke oven gas and CO2 to produce high-temperature synthesis gas. The purpose of the present application is to overcome the problems of high carbon consumption, high emission, difficult energy recycling, and inefficient utilization of coke oven gas resources in traditional ironmaking processes, and to provide a method for improving the energy efficiency and process stability of coke oven gas reduction ironmaking processes. The present application can simultaneously realize CO2 resource utilization and efficient conversion of coke oven gas, and directly complete the iron ore reduction reaction using the sensible heat of high-temperature reducing gas, reducing the external energy supply demand and significantly improving the utilization rate of coal resources and the overall efficiency of the energy system.

[0006] In one aspect, a device for reducing iron by reforming coke oven gas and CO2 to produce high-temperature synthesis gas is provided. The device comprises:

[0007] a reforming reactor filled with catalyst in its shell, the catalyst being used to catalyze the dry reforming reaction of CH4 in coke oven gas and CO2 to produce high-temperature reducing gas mainly composed of CO and H2;

[0008] a high-temperature reduction ironmaking furnace, which introduces high-temperature reducing gas at its bottom and contacts with iron ore particles added from top to bottom in the shell to complete the solid direct reduction reaction and produce reduced iron;

[0009] wherein the heating methods of the reforming reactor and the high-temperature reduction ironmaking furnace both use high-temperature flue gas in the tube pass to heat, and the reforming reaction and the reduced iron reaction are carried out in the shell.

[0010] In some embodiments, the main body of the reforming reactor is a high-temperature and corrosion-resistant sealed reaction kettle that can withstand a high temperature of 800-1200℃ and a pressure of >0.1 MPa; the sealed reaction kettle is filled with shaped reforming catalyst, and the bed of the reforming catalyst is arranged in a dispersed packing manner or a uniform stacking manner to ensure that the pressure drop is the same at different positions in the reforming reactor.

[0011] In some embodiments, the sealed reaction kettle is provided with a first column of high-temperature flue gas passages, and the tubes in the first column of high-temperature flue gas passages are uniformly arranged in the reforming reactor; the high-temperature reduction ironmaking furnace is provided with a second column of high-temperature flue gas passages, and the tubes in the second column of high-temperature flue gas passages are uniformly arranged in the high-temperature reduction ironmaking furnace. This ensures that the temperature at different cross-sectional positions in the shell after heat exchange in the tube is equivalent.

[0012] In some embodiments, the first column of high-temperature flue gas passages and the second column of high-temperature flue gas passages are connected by a pipeline, and a high-temperature flue gas heating passage for heating is provided on the pipeline.

[0013] In some embodiments, the top of the reforming reactor is provided with a raw gas inlet for the mixed gas of coke oven gas and CO2 to enter; the bottom of the reforming reactor is provided with a high-temperature flue gas inlet on the sidewall thereof in communication with the first column of tubular high-temperature flue gas passages; the bottom of the reforming reactor is provided with a bottom deposition tank for the fine carbon deposit and solid particles generated in the reaction process to settle, and the carbon deposit particles, broken solid catalyst and carrier particles formed in the reaction process are discharged in time, so as to ensure the stability of the whole bed pressure drop.

[0014] In some embodiments, the iron ore particle layers are sequentially added from top to bottom in the furnace body of the high-temperature reduction iron-making furnace, and the bottom of the second column of tubular high-temperature flue gas passages is provided with a hot flue gas outlet.

[0015] In some embodiments, the top of the high-temperature reduction iron-making furnace is provided with an iron ore inlet.

[0016] In some embodiments, the bottom of the high-temperature reduction iron-making furnace is a reduced iron outlet, and the upper part of the furnace body is provided with a top gas outlet for discharging tail gas and partially recovering waste heat.

[0017] In another aspect, a process for reducing iron by reforming coke oven gas and CO2 to produce high-temperature synthesis gas is provided, which uses the device described in the above aspect. The process comprises the following steps:

[0018] 1) Raw material preparation and introduction: after dust removal and desulfurization, the coke oven gas is mixed with the industrial by-product CO2 to form a mixed gas, which is sent into the reforming reactor;

[0019] 2) Catalytic reforming reaction: the mixed gas flows from top to bottom in the reforming reactor, passing through the heat exchange tube bundle area filled with reforming catalyst, wherein part of the coke oven gas burned by the external combustion furnace is introduced into the first column of tubular high-temperature flue gas passages through the high-temperature flue gas inlet for heating, and under the action of high temperature and reforming catalyst, the following reactions occur:

[0020] Dry reforming reaction, CH4 + CO2 → 2CO + 2H2,

[0021] Side reaction, if containing water vapor, CH4 + H2O → CO + 3H2,

[0022] The high-temperature reduction gas generated by the reaction is discharged from the outlet at the bottom of the reforming reactor, carrying sensible heat and directly transported to the high-temperature reduction iron-making furnace;

[0023] 3) Direct reduction iron-making: iron ore is continuously added from the iron ore inlet at the top of the high-temperature reduction iron-making furnace, and the particle size is controlled to be ≯ 50 mm; the high-temperature reduction gas introduced from the reforming reactor flows upward from the bottom of the high-temperature reduction iron-making furnace, and is in countercurrent contact with the falling iron ore, to perform a solid-state reduction reaction:

[0024] Fe₂O₃ + 3CO → 2Fe + 3CO₂

[0025] Fe₂O₃ + 3H₂ → 2Fe + 3H₂O

[0026] The temperature gradient inside the high-temperature reduction ironmaking furnace is controlled at 600-800℃ at the top, 800-1000℃ in the middle, and 900-1100℃ at the bottom. Auxiliary heating gas is introduced through a high-temperature flue gas heat supply channel to maintain thermal balance. The reduction time of iron ore in the furnace is 1-6 hours, with a reduction rate of ≥90%. The generated direct reduced iron, with a metallization rate of ≥92%, is discharged from the bottom of the high-temperature reduction ironmaking furnace as a raw material for subsequent steelmaking.

[0027] 4) Tail gas treatment and circulation: The top gas of the high-temperature reduction ironmaking furnace is discharged through the top gas outlet. After partial recovery of waste heat, it is discharged or circulated for heat replenishment. The remaining tail gas enters the tail gas combustion furnace through the combustion outlet for combustion treatment. The heat can be used to preheat the feed or generate electricity. At the same time, the gas after combustion is treated by desulfurization, dust removal and CO2 capture.

[0028] In some embodiments, the main components of coke oven gas are CH4 and H2, with a mixing ratio of CH4:CO2 = 1:1-1:2; the reforming catalyst is a nickel-based catalyst, and it is diluted with high-temperature quartz sand.

[0029] The apparatus and process for producing high-temperature syngas from coke oven gas and CO2 reforming according to the present invention for use in iron reduction has at least one of the following advantages:

[0030] (1) This invention designs a device and process for using coke oven gas and CO2 reforming to produce high-temperature syngas for reduction ironmaking. Through this device and process, a low-pollution and low-consumption reduction ironmaking process can be achieved, overcoming the defects of high carbon emissions and difficulty in recycling heat in traditional processes. It provides an innovative solution for green reduction ironmaking production and provides strong technical support for global energy transition.

[0031] (2) The device and process can simultaneously achieve efficient conversion of CO2 and resource utilization of coke oven gas. The high-temperature reducing gas generated carries sensible heat to provide energy for the reduction reaction, significantly reducing the external energy demand. Through tail gas recovery and recycling, the carbon emissions and energy consumption of direct reduced iron can be greatly reduced. The process of this invention is short, energy-efficient, and low-polluting, and can effectively replace some traditional blast furnace ironmaking processes, providing technical support for green and low-carbon metallurgy. Attached Figure Description

[0032] These and / or other aspects and advantages of the present invention will become apparent and readily understood from the following description of preferred embodiments taken in conjunction with the accompanying drawings, in which:

[0033] Figure 1 A schematic diagram of an apparatus for reducing ironmaking by reforming coke oven gas and CO2 to produce high-temperature syngas is shown according to an embodiment of the present invention. Detailed Implementation

[0034] The technical solution of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. In this specification, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the overall inventive concept of the present invention and should not be construed as a limitation thereof.

[0035] Example 1

[0036] In this embodiment, coke oven gas obtained through standard process treatment is combined with CO2 reformed high-temperature syngas for reduction ironmaking. The specific operation is as follows:

[0037] First, coke oven gas and industrial by-product CO2 are purified through dust removal and desulfurization processes, and the resulting raw material gas is fed into the shell of reforming reactor 11 through raw material gas inlet 1. The shell of reforming reactor 11 is filled with reforming catalyst 8 (Ni-based catalyst is used in this embodiment), and a series of tubular high-temperature flue gas tubes are uniformly arranged within the cavity of reforming reactor 11 to form a first series of tubular high-temperature flue gas channels 12. High-temperature flue gas supplied by an external combustion furnace enters through high-temperature flue gas inlet 9 and passes through the tubes of the first series of tubular high-temperature flue gas channels 12, providing continuous heat to the gas in the reaction zone of the shell side, ensuring the smooth progress of the dry reforming reaction. The mixed gas undergoes a carbon-hydrogen complementary reaction in the catalyst bed, generating a high-temperature reducing gas rich in CO and H2. Fine carbon deposits and solid particles generated during the reaction settle in the bottom sedimentation tank 10 of the device, facilitating periodic discharge and ensuring long-term stable operation of the device.

[0038] The generated high-temperature reducing gas enters directly into the high-temperature reduction ironmaking furnace 13, which is connected to it, through outlet 7. The high-temperature reduction ironmaking furnace 13 has an iron ore inlet 3 at the top, where cold-pressed iron ore particles are continuously added, arranged in a top-to-bottom layer. The high-temperature reducing gas introduced from the reforming reactor 11 enters the shell side of the second tubular high-temperature flue gas channel 14 within the high-temperature reduction ironmaking furnace 13 from bottom to top, contacting the descending iron ore particles countercurrently. A solid-state reduction reaction occurs within the furnace shell space, gradually reducing Fe2O3 to metallic iron. The second tubular high-temperature flue gas channel 14 inside the high-temperature reduction ironmaking furnace 13 allows the flue gas heated by the reforming reactor 11 to enter the channel and maintain the temperature required for the reaction inside the furnace. To prevent insufficient heat supply, a high-temperature flue gas supplementary heating channel 2 is provided to introduce some high-temperature flue gas to maintain the temperature gradient and thermal balance within the furnace.

[0039] The high-temperature reduction blast furnace 13 has a reduced iron outlet 6 at the bottom, which can continuously discharge the obtained direct reduced iron (DRI) product with a metallization rate of ≥92%, meeting the requirements of subsequent steelmaking. The high-temperature reduction blast furnace 13 has a furnace top gas outlet 4 at the top. After heat exchange and recovery, part of the tail gas is returned as supplementary heating gas, and the remainder enters the tail gas combustion furnace to mix and burn with air. The generated hot flue gas is discharged through the hot flue gas outlet 5 for feeding preheating or power generation. The combustion tail gas also undergoes desulfurization, dust removal and CO2 capture to achieve carbon emission reduction.

[0040] The entire unit achieves resource utilization of coke oven gas and CO2 through the integrated coupling of the reforming reactor 11 and the high-temperature reduction blast furnace 13. The generated high-temperature reducing gas directly provides a reducing atmosphere and sensible heat for solid iron ore, significantly reducing the external energy supply requirement. Tail gas recirculation and regular cleaning of the bottom sedimentation tank 10 ensure the unit's energy efficiency and stability. Compared with traditional blast furnace processes, this invention significantly reduces carbon emissions, demonstrating the advantages of green and low-carbon metallurgy.

[0041] Example 2

[0042] In this embodiment, the mixing ratio is adjusted for industrial waste gas with high CO2 content. The specific operation is as follows:

[0043] The feed gas inlet 1 of the reforming reactor 11 is connected to a mixture of purified coke oven gas and high-concentration CO2. The shell of the reforming reactor 11 is filled with a reforming catalyst 8, which is a Ni-based catalyst (Pt-Rh-Ni) doped with precious metals. High-temperature flue gas enters the shell of the reforming reactor 11 through the high-temperature flue gas inlet 9 and is heated through the high-temperature tube passage of the first tubular high-temperature flue gas channel 12 to maintain the required reaction temperature. Dry reforming occurs within the catalyst bed in the shell. Simultaneously, due to the high water content of the by-product gas, some steam reforming may also occur, further increasing H2 production. Fine particles generated during the reaction are deposited in the bottom sedimentation tank 10, which is cleaned regularly to ensure stable operation of the catalyst bed. The high-temperature reducing gas generated during reforming is directly introduced into the high-temperature reduction ironmaking furnace 13 through the outlet 7.

[0044] The high-temperature reduction ironmaking furnace 13 is connected to the reforming reactor 11. Iron ore with an average particle size of 35 mm is added through the iron ore inlet 3 and descends stepwise in the furnace bed. High-temperature reducing gas rich in CO and H2, supplied by the reforming reactor 11, enters from the bottom and flows counter-currently through the bed, completing the stepwise reduction reaction in different temperature ranges. A second tubular high-temperature flue gas channel 12 is uniformly arranged inside the furnace. The flue gas heated by the reforming reactor 11 enters this channel to ensure a stable temperature gradient from top to bottom within the furnace, preventing insufficient heat supply. A high-temperature flue gas supplementary heating channel 2 is also provided to maintain sufficient heat supply. The final obtained direct reduced iron is discharged from the reduced iron outlet 6.

[0045] The exhaust gas from the top of the high-temperature reduction blast furnace 13 is partially recycled after being discharged through the furnace top gas outlet 4 to improve energy utilization. The remaining portion enters the exhaust gas combustion furnace, and the hot flue gas after combustion is discharged through the hot flue gas outlet 5 and used for power generation or preheating of raw materials. Through desulfurization, dust removal, and CO2 capture treatment, a significant reduction in carbon emissions is achieved. Overall operation shows that the unit can maintain high conversion efficiency and high reduction rate even when handling high CO2 by-product gas, resulting in a substantial reduction in carbon emissions.

[0046] Example 3

[0047] In this embodiment, the pressure and flow rate are optimized for coke oven gas with low CH4 content. The specific operations are as follows:

[0048] Coke oven gas and by-product CO2 are mixed and then enter the shell of reforming reactor 11 through feed gas inlet 1. Due to the relatively low CH4 content, reforming reactor 11 operates at a lower operating pressure. The shell is filled with reforming catalyst 8 (Ni-based catalyst is used in this embodiment). The reforming reactor 11 has uniformly arranged tubular channels of the first tubular high-temperature flue gas channel 12. The high-temperature flue gas generated by combustion enters the tubular channels through high-temperature flue gas inlet 9 to maintain the reaction temperature. The reaction gas undergoes a dry reforming reaction in the catalytic bed to generate high-temperature reducing gas containing CO and H2. Some carbon deposits and impurities settle to the bottom sedimentation tank 10 to prevent blockage.

[0049] The generated high-temperature reducing gas is directly supplied to the high-temperature reduction ironmaking furnace 13 through outlet 7. Iron ore particles are continuously added to the high-temperature reduction ironmaking furnace 13 from the top, and the raw material descends step by step in the material layer within the shell side of the furnace 13. The high-temperature reducing gas, fed into the shell side of the furnace 13 from the bottom, flows upwards, contacting the falling ore counter-currently, and completing the reduction reaction in different temperature zones. A uniform tubular high-temperature flue gas channel (i.e., the second tubular high-temperature flue gas channel 14) is provided inside the furnace to maintain a stable temperature distribution. A high-temperature flue gas reheating channel 2 is also provided to maintain sufficient heat supply and ensure complete ore reduction. Finally, the direct reduced iron is discharged through the bottom reduced iron outlet 6.

[0050] The exhaust gas from the top of the high-temperature reduction blast furnace 13 is discharged through the furnace top gas outlet 4. Part of it is recycled back to the unit for supplementary heating, while the remainder enters the exhaust gas combustion furnace for combustion. The hot flue gas generated by combustion is discharged through the hot flue gas outlet 5 for feed preheating. After combustion, the exhaust gas is discharged after desulfurization, dust removal, and CO2 capture, achieving carbon emission reduction. This type of unit can still operate stably under low CH4 gas source conditions, with a carbon emission reduction of approximately 35%, demonstrating good environmental benefits and energy utilization efficiency.

[0051] The apparatus and process for producing high-temperature syngas from coke oven gas and CO2 reforming according to the present invention for use in iron reduction has at least one of the following advantages:

[0052] (1) This invention designs a device and process for using coke oven gas and CO2 reforming to produce high-temperature syngas for reduction ironmaking. Through this device and process, a low-pollution and low-consumption reduction ironmaking process can be achieved, overcoming the defects of high carbon emissions and difficulty in recycling heat in traditional processes. It provides an innovative solution for green reduction ironmaking production and provides strong technical support for global energy transition.

[0053] (2) The device and process can simultaneously achieve efficient conversion of CO2 and resource utilization of coke oven gas. The high-temperature reducing gas generated carries sensible heat to provide energy for the reduction reaction, significantly reducing the external energy demand. Through tail gas recovery and recycling, the carbon emissions and energy consumption of direct reduced iron can be greatly reduced. The process of this invention is short, energy-efficient, and low-polluting, and can effectively replace some traditional blast furnace ironmaking processes, providing technical support for green and low-carbon metallurgy.

[0054] While some embodiments of the inventive concept have been shown and described, those skilled in the art will understand that changes may be made to these embodiments without departing from the principles and spirit of the inventive concept, the scope of which is defined by the claims and their equivalents.

Claims

1. A device for reducing iron making by reforming coke oven gas with CO2 to produce high temperature synthesis gas, characterized in that, The device comprises: a reforming reactor, a shell of which is filled with catalysts for catalytic dry reforming reaction of CH4 and CO2 in coke oven gas to generate high-temperature reducing gas mainly composed of CO and H2; a high-temperature reduction iron-making furnace, the high-temperature reducing gas is introduced into the bottom of the high-temperature reduction iron-making furnace to contact with iron ore particles added from top to bottom in the shell in countercurrent, to complete the solid-state direct reduction reaction to generate reduced iron; wherein the heating mode of the reforming reactor and the high-temperature reduction iron-making furnace both adopts high-temperature flue gas heating in the tube side, and the reforming reaction and the reduced iron reaction are both carried out in the shell.

2. The device according to claim 1, wherein the main body of the reforming reactor is a high-temperature-resistant and corrosion-resistant sealed reaction kettle, which can withstand a high temperature of 800-1200℃ and a pressure of >0.1MPa; the sealed reaction kettle is internally filled with shaped reforming catalysts, and the bed layer of the reforming catalysts is arranged in a dispersed packing manner or a uniform stacking manner.

3. The device according to claim 2, wherein a first column of tubular high-temperature flue gas passages is arranged in the sealed reaction kettle, and the tubes in the first column of tubular high-temperature flue gas passages are uniformly arranged in the reforming reactor; a second column of tubular high-temperature flue gas passages is arranged in the high-temperature reduction iron-making furnace, and the tubes in the second column of tubular high-temperature flue gas passages are uniformly arranged in the high-temperature reduction iron-making furnace.

4. The device according to claim 3, wherein the first column of tubular high-temperature flue gas passages and the second column of tubular high-temperature flue gas passages are connected by a pipeline, and a high-temperature flue gas heating passage for heat supplement is arranged on the pipeline.

5. The device according to claim 4, wherein a raw gas inlet for mixed gas of coke oven gas and CO2 is arranged at the top of the reforming reactor; a high-temperature flue gas inlet in communication with the first column of tubular high-temperature flue gas passages is arranged on the side wall of the bottom of the reforming reactor; a bottom deposition tank for deposition of fine carbon and solid particles generated in the reaction process is arranged at the bottom of the reforming reactor, so as to timely discharge carbon particles, broken solid catalysts and carrier particles formed in the reaction process.

6. The device according to claim 5, wherein iron ore particle layers are sequentially added from top to bottom in the furnace body of the high-temperature reduction iron-making furnace, a hot flue gas outlet is arranged at the bottom of the second column of tubular high-temperature flue gas passages.

7. The device according to claim 6, wherein an iron ore inlet is arranged at the top of the furnace body of the high-temperature reduction iron-making furnace.

8. The device according to claim 7, wherein the furnace body bottom of the high-temperature reduction iron-making furnace is a reduced iron outlet, and a furnace top gas outlet is arranged at the upper part of the furnace body, for discharging tail gas and partially recovering waste heat.

9. A process for reducing iron-making by reforming coke oven gas and CO2 to generate high-temperature synthesis gas, the process uses the device according to any one of claims 1-8, and the process comprises the following steps: 1) raw material preparation and introduction: after dust removal and desulfurization, the coke oven gas is mixed with industrial by-product CO2 to form a mixed gas, which is sent to the reforming reactor; 2) catalytic reforming reaction: mixed gas flows from top to bottom in the reforming reactor, through the heat exchange tube bundle area filled with reforming catalyst, where part of the coke oven gas burned by the external combustion furnace is introduced into the first column of high-temperature flue gas passage for heating through the high-temperature flue gas inlet, and under the action of high temperature and reforming catalyst, the following reactions occur: dry reforming reaction, CH4 + CO2 → 2CO + 2H2, side reaction, if containing water vapor, CH4 + H2O → CO + 3H2, The high-temperature reducing gas generated by the reaction is discharged from the outlet at the bottom of the reforming reactor, carrying sensible heat and directly transported to the high-temperature reduction iron-making furnace; 3) direct reduction ironmaking: iron ore is continuously added from the iron ore inlet at the top of the high-temperature reduction ironmaking furnace, with a particle size control of ≯50 mm, and the high-temperature reducing gas introduced from the reforming reactor flows upward from the bottom of the high-temperature reduction ironmaking furnace, countercurrently contacting the falling iron ore, and performing solid-state reduction reaction: Fe2O3 + 3CO → 2Fe + 3CO2, Fe2O3 + 3H2 → 2Fe + 3H2O, The temperature gradient in the high-temperature reduction ironmaking furnace is controlled to be 600-800℃ at the top, 800-1000℃ in the middle, and 900-1100℃ at the bottom, auxiliary heating gas is introduced through the high-temperature flue gas heating passage to maintain heat balance, the reduction time of iron ore in the furnace is 1-6 hours, the reduction rate is ≮90%, and the generated direct reduced iron has a metallization rate of ≮92%, which is discharged from the bottom of the high-temperature reduction ironmaking furnace as subsequent steelmaking raw material; 4) tail gas treatment and recycling: the gas at the top of the high-temperature reduction ironmaking furnace is led out through the top gas outlet, part of the waste heat is recovered and then discharged or recycled for heating, and the remaining tail gas enters the tail gas combustion furnace through the combustion outlet for combustion treatment, and the heat can be used for preheating the feed or generating electricity, At the same time, the gas after combustion is treated by desulfurization, dust removal and CO2 capture.

10. The process according to claim 9, characterized in that, the main components of coke oven gas are CH4 and H2, and the mixing ratio is CH4:CO2 = 1:1-1:2; the reforming catalyst is a nickel-based catalyst, and high-temperature quartz sand is used for dilution.

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