Furnace top gas cyclic reforming process and system

Abstract

The invention discloses a furnace top gas cyclic reforming process and system, and the reforming process comprises the following steps: S1, heating furnace top gas generated by a blast furnace to 1000-1200 DEG C to obtain high-temperature gas; s2, mixing the high-temperature coal gas with coal, and carrying out electromagnetic induction heating coal gas reforming reaction to generate reduced coal gas which is 900-1000 DEG C and contains CO and H2; s3, performing plasma heating on the reduced gas to 1400-1800 DEG C to obtain high-temperature reduced gas; s4, recycling the high-temperature reduction coal gas to the lower part of the blast furnace for circular treatment; according to the method, a carbon capture device of a conventional oxygen blast furnace and a top combustion type gas heating furnace and a CO2 removal device of a carbon circulation blast furnace are replaced by circular reforming of the furnace top gas, so that the energy consumption and the equipment investment of the technological process are reduced.

Description

Technical Field

[0001] This invention relates to the field of blast furnace ironmaking technology, and in particular to a furnace top gas circulation reforming process and system. Background Technology

[0002] As a pillar industry of the national economy, the steel industry faces severe challenges of high energy consumption and large carbon emissions while supporting economic development. In the blast furnace-converter long-process smelting, the energy consumption and carbon emissions of the ironmaking process account for as much as 70%-90%, making it a key link in achieving green and low-carbon transformation. Traditional blast furnace technology suffers from significant heat energy waste and efficiency bottlenecks: its hot blast system heats air by burning coal gas, with a thermal efficiency typically below 80%, and the emitted low-temperature furnace top gas (approximately 150-200℃) carries a large amount of sensible heat that is directly dissipated. Simultaneously, the blast furnace gas is rich in CO2 (approximately 20-25%) and is largely diluted by N2, resulting in a low calorific value (approximately 3.0-3.5 MJ / m³). 3 The inefficiency of carbon recycling hinders the improvement of carbon cycle efficiency.

[0003] To overcome these limitations, oxygen blast furnace and carbon-circulating blast furnace technologies emerged. For example... Figure 1 As shown, its core lies in using pure oxygen instead of traditional air for smelting, fundamentally reducing the mixing of inert nitrogen and significantly increasing the concentration of effective components (CO, H2) in the top gas, thus creating conditions for gas recycling. However, these new blast furnace processes still face many bottlenecks in practical applications. Current mainstream gas recycling technologies still require complex carbon capture (CCS) and CO2 removal devices, resulting in lengthy process flows and high equipment investment and operating energy consumption. In addition, traditional regenerative gas heaters suffer from large temperature fluctuations (±50℃), low heating efficiency (≤75%), and high NOx emissions, leading to a decrease in the calorific value of the circulating gas and restricting the system's economic efficiency and carbon reduction effect.

[0004] Therefore, it is essential to find a technical solution to address the high energy consumption and low gas heating efficiency in the separation and utilization of CO2 from blast furnace top gas for new ironmaking processes such as carbon-cycle blast furnaces. Summary of the Invention

[0005] In view of this, this application provides a furnace top gas circulating reforming process and system to solve the problems of high energy consumption and low gas heating efficiency in the separation and utilization of CO2 from blast furnace top gas.

[0006] To achieve the above technical objectives, this application adopts the following technical solution: In a first aspect, this application provides a furnace top gas recirculation reforming process, comprising the following steps: S1. Heat the blast furnace top gas to 1000-1200℃ to obtain high-temperature gas; S2. Mix high-temperature coal gas with coal and perform electromagnetic induction heating coal gas reforming reaction to generate reducing coal gas containing CO and H2 at 900-1000℃. S3. The reducing gas plasma is heated to 1400-1800℃ to obtain high-temperature reducing gas; S4. The high-temperature reducing gas is recycled to the lower part of the blast furnace for further processing.

[0007] Preferably, the composition of the top gas is as follows: CO volume content 30%–45%, H2 volume content 20%–30%, CO2 volume content 15%–25%, H2O volume content 10%–20%, and N2 volume content <5%.

[0008] Preferably, the composition of the reducing gas is as follows: CO volume content is 60% to 90%, H2 volume content is 30% to 45%, and the sum of CO2 and H2O volume content is <5%.

[0009] Preferably, the coal composition includes: 50%~55% fixed carbon by mass, 15%~18% moisture by mass, 4%~7% ash by mass, and 28%~32% volatile matter by mass; the volatile matter composition includes: 10% CO2 by mass, 40% CO by mass, 15% CH4 by mass, 30% H2 by mass, and 5% N2 by mass.

[0010] Preferably, in step S1, prior to the heating treatment, the top gas of the furnace is further subjected to dust removal and / or dehydration.

[0011] Preferably, the energy required for heating in step S1 is provided by heat exchange of high-temperature metallurgical waste gas; the energy required for electromagnetic induction heating of the gas reforming reaction is provided by green electricity and / or oxidation reaction inside the reaction system; the energy required for plasma heating is supplied by green electricity; and the heat inside the blast furnace is provided by high-temperature reducing gas.

[0012] Preferably, between steps S2 and S3, gas-solid separation is further performed on the products of the electromagnetic induction heating coal gas reforming reaction.

[0013] Secondly, this application provides a blast furnace gas circulating reforming system, including a blast furnace body, a preheating device, an electromagnetic induction reforming device, and a plasma heating device connected sequentially along the material flow direction; the blast furnace body's top gas outlet is connected to the inlet of the preheating device via a pipeline; the preheating device's outlet is connected to the gas inlet at the top of the electromagnetic induction reforming device via a pipeline; the electromagnetic induction reforming device is provided with a coal inlet for adding coal into the device; the electromagnetic induction reforming device's gas outlet is connected to the inlet of the plasma heating device via a pipeline; and the plasma heating device's outlet is connected to the tuyeres at the bottom of the blast furnace body via a pipeline.

[0014] Preferably, the electromagnetic induction reforming device is divided into a reaction zone, an expansion section, and a gas-solid separation zone from top to bottom, wherein the reaction zone is equipped with an induction coil that provides energy for the reforming reaction.

[0015] Preferably, the plasma heating device uses a graphite electrode and is equipped with a water-cooled bottom electrode and a bottom slag outlet.

[0016] The beneficial effects of this application are as follows: This application replaces the carbon capture device of a conventional oxygen blast furnace and the top-fired gas heater and CO2 removal device of a carbon-circulating blast furnace by top gas recirculation reforming, thereby reducing the energy consumption and equipment investment of the process.

[0017] This application utilizes electromagnetic induction gasification reforming and plasma heating, combined with green electricity supply, to achieve efficient conversion of green energy into chemical and thermal energy. This is beneficial for improving the calorific value of circulating coal gas and achieving breakthroughs in heating efficiency, fundamentally reducing fossil energy consumption.

[0018] This application uses high-volatile bituminous coal as reforming feedstock, which reduces raw material costs; its high volatile content characteristics can input a richer range of coal gas components into the system, reducing the demand for top gas reforming and reducing green energy consumption in the reforming and heating processes.

[0019] The process described in this application achieves stable operation of the blast furnace system and preheating, reforming, and heating modules through multi-energy domain synergy of thermo-electricity-chemistry, thereby reducing nitrogen oxides (NOx). x (Emissions) are environmentally friendly. Attached Figure Description

[0020] Figure 1 This is a flowchart of the top gas treatment process in a carbon-cycle blast furnace in the existing technology.

[0021] Figure 2 This is a schematic diagram of a plasma heating device.

[0022] Figure 3 This is a flowchart of the system apparatus of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0024] This application provides a furnace top gas recirculation reforming process, including the following steps: S1. Heat the blast furnace top gas to 1000-1200℃ to obtain high-temperature gas; S2. Mix high-temperature coal gas with coal and perform electromagnetic induction heating coal gas reforming reaction to generate reducing coal gas containing CO and H2 at 900-1000℃. S3. The reducing gas plasma is heated to 1400-1800℃ to obtain high-temperature reducing gas; S4. The high-temperature reducing gas is recycled to the lower part of the blast furnace for further processing.

[0025] This application provides an innovative process centered on gas staged upgrading and energy recycling. This scheme, through multi-energy domain synergy of heat, electricity, and chemicals, successfully replaces the carbon capture device in conventional oxygen blast furnaces and the top-fired gas heater and CO2 removal device in carbon-circulating blast furnaces. Employing a technical approach combining CO2 reforming and green electricity heating, it effectively solves the dual technical challenges of high energy consumption for CO2 separation and utilization and low gas heating efficiency in traditional blast furnace top gas. This process fully utilizes CO2 and H2O in the top gas, achieving efficient conversion of green energy into chemical and thermal energy through a system synergy of hot blast stove preheating, induction furnace reforming, and plasma furnace heating. This increases the calorific value of the circulating gas, achieves a breakthrough in heating efficiency, significantly reduces the overall energy consumption of the process, and fundamentally reduces fossil fuel consumption.

[0026] In step S1, the blast furnace includes one or more of the following: hydrocarbon co-processing blast furnace and carbon recycling blast furnace, such as the existing 430m³ blast furnace at Baosteel. 3 HyCROF blast furnace; the heating device is a heat exchange hot blast stove with an inlet gas temperature of 100℃ and an outlet gas temperature of 1000~1200℃. The heat exchange hot blast stove achieves heating by utilizing the waste heat of metallurgical waste gas. In step S2, high-temperature coal gas, maintained at 1000–1200°C, is transported from the top to the reforming furnace tube of the electromagnetic induction heating coal gas reforming device. Simultaneously, room-temperature lump coal or high-volatile bituminous coal is added into the furnace tube. The coal gas flows from top to bottom through the furnace tube, undergoing electromagnetic induction heating and reforming reactions within the furnace. The reforming gasifier is directly heated by silicon carbide heating rods. The number and power of each section of silicon carbide heating rods can be designed according to the required heat absorption in the reaction zone, stabilizing the temperature in the reaction zone within the reaction range (950–1050°C). The working principle of this device is that high-temperature coal gas passes through the coal bed from top to bottom. CO2 and H2O react with the carbon in the coal to generate reducing gases CO and H2. Simultaneously, the coal undergoes volatile matter removal at high temperatures, providing additional reducing gases for the high-temperature coal gas. Through a series of chemical reactions and physical processes, although the temperature decreases, the reducing potential of the coal gas increases significantly, and the CO2 and H2O contents decrease significantly. The electromagnetic induction heating gas reforming unit employs medium-frequency electromagnetic induction technology and is divided into three functional zones: high-temperature gas is reformed into high-reduction-potential gas in the reaction zone, and then leaves the unit through the expansion section, while reaction slag such as coal ash is discharged from the slag outlet through the gas-solid separation zone. This process achieves highly efficient dry reforming of CO2 and H2O in the gas without the addition of external catalysts or complex pretreatment, directly generating high-value-added CO and H2 reduced gas. This not only significantly improves the calorific value of the gas but also enables targeted control of the gas composition, laying a solid foundation for subsequent efficient utilization.

[0027] In step S3, the reducing gas with high reducing potential obtained at the outlet of the electromagnetic induction heating gas reforming device is kept at a temperature of 900-1000℃ and transported to the plasma heating device to obtain high-temperature reducing gas at a temperature of 1400-1800℃, which significantly improves the calorific value of the gas. The high-temperature electric arc (temperature ≥3000℃) generated by the plasma heating device can accurately and rapidly heat the reformed gas, ensuring that the gas temperature accurately meets the combustion requirements of the tuyeres area of ​​the carbon cycle blast furnace, thereby optimizing the thermodynamic conditions inside the blast furnace.

[0028] In step S4, high-temperature reducing gas with high reducing potential is injected into the blast furnace from the lower tuyeres of the blast furnace in step S1. The gas formed in the tuyeres swirling zone transfers heat and mass from bottom to top and is then discharged from the blast furnace. The resulting top gas is then recycled from step S1 to step S4.

[0029] In some embodiments, the composition of the top gas is as follows: CO volume content 30%–45%, H2 volume content 20%–30%, CO2 volume content 15%–25%, H2O volume content 10%–20%, and N2 volume content <5%. The initial temperature of the top gas is 100–200°C.

[0030] In this embodiment, the composition of the high-temperature reducing gas is the same as that of the top gas. The high-temperature reducing gas meets the temperature and composition requirements for blast furnace gas injection. It enters the blast furnace and transfers heat and mass from bottom to top, and then exits from the blast furnace. The resulting top gas is heated by the hot blast stove and then circulated into the electromagnetic induction gas reforming device and the plasma heater, realizing the cyclic injection of gas based on hot blast stove preheating - induction furnace reforming - plasma furnace heating.

[0031] In some embodiments, the composition of the reducing gas is as follows: CO volume content is 60%–90%, H2 volume content is 30%–45%, and the sum of the volume contents of CO2 and H2O is <5%.

[0032] In some embodiments, the coal includes high-volatile bituminous coal or coal lumps; the high-volatile bituminous coal comprises: fixed carbon volume content of 50%~55%, moisture volume content of 15%~18%, ash volume content of 4%~7%, and volatile matter volume content of 28%~32%; the volatile matter comprises: CO2 volume content of 10%, CO volume content of 40%, CH4 volume content of 15%, H2 volume content of 30%, and N2 volume content of 5%. In this embodiment, high-volatile bituminous coal can input a richer composition and quantity of gas (hydrogen-containing components such as H2 and CH4) into the system, which can reduce the demand for top gas reforming and ultimately reduce the green energy consumption of the reforming process and subsequent plasma heating process.

[0033] In some embodiments, step S1 further includes removing dust and / or dehydrating the furnace top gas before the heating treatment.

[0034] In some embodiments, the energy required for heating in step S1 is provided by a high-temperature metallurgical waste gas heat exchanger.

[0035] In some embodiments, the energy required for the electromagnetic induction heating gas reforming reaction is provided by green electricity and / or oxidation reactions within the reaction system.

[0036] In some embodiments, the energy required for plasma heating is supplied by green electricity.

[0037] In this embodiment, plasma heating is achieved by a plasma heating device, which uses graphite electrodes. The principle of gas heating is to generate plasma through electric arc discharge. Plasma has the characteristics of high temperature and high heat capacity, which can effectively heat the gas. After the plasma heating device completes the gas heating, the high-temperature reducing gas is discharged from the other side. The furnace bottom is equipped with a water-cooled bottom electrode and a slag outlet is set at the bottom to achieve gas-solid separation.

[0038] In some embodiments, between steps S2 and S3, gas-solid separation is further performed on the products of the electromagnetic induction heating coal gas reforming reaction.

[0039] Specifically, the products of the electromagnetic induction heating gas reforming reaction are separated into gas and solid in the lower part of the electromagnetic induction furnace reforming gas heating device. The reducing gas (rich in CO and H2) is discharged from the side extension section, and the coal ash is discharged from the lower part of the induction furnace.

[0040] In some embodiments, the heat inside the blast furnace is provided by high-temperature reducing gas; the blast furnace body of this application does not require the consumption of additional fossil fuels, and the added coke only undertakes the functions of carburization and maintaining the blast furnace skeleton, and the heat inside the furnace is provided by high-temperature reducing gas (circulating gas) with high temperature and high reducing potential.

[0041] like Figure 3 As shown, this application provides a blast furnace gas circulating reforming system. The system forms a closed material flow circulation loop, including a blast furnace body, a preheating device, an electromagnetic induction reforming device, and a plasma heating device connected sequentially along the material flow direction. The blast furnace body's top gas outlet is connected to the inlet of the preheating device via a pipeline to transport the top gas to the preheating device. The preheating device's outlet is connected to the gas inlet at the top of the electromagnetic induction reforming device via a pipeline to transport the preheated high-temperature gas to the reforming device. The electromagnetic induction reforming device is equipped with a coal inlet... The inlet is used to add coal into the device; the gas outlet of the electromagnetic induction reforming device is connected to the inlet of the plasma heating device through a pipeline, which is used to transport the reformed reducing gas to the heating device; the outlet of the plasma heating device is connected to the tuyer at the bottom of the blast furnace body through a pipeline, which is used to inject the final high-temperature reducing gas back into the blast furnace; the top gas generated by the blast furnace body flows through the preheating device, the electromagnetic induction reforming device and the plasma heating device in sequence for upgrading and heating, and then returns to the blast furnace body to form a closed-loop material flow of the top gas.

[0042] In this system, the electromagnetic induction furnace achieves dry reforming of CO2 and H2O in coal gas through medium-frequency electromagnetic induction, generating CO and H2 syngas and significantly improving the calorific value of the coal gas. The plasma furnace utilizes a high-temperature electric arc (≥3000℃) to precisely heat the reformed coal gas, meeting the combustion requirements of the blast furnace tuyeres. These processes overcome the limitations of calorific value decay and temperature fluctuations in traditional coal gas circulation, increasing the calorific value of circulating coal gas by over 200%, achieving a heating efficiency exceeding 90%, and simultaneously realizing near-zero CO2 emissions and NO emissions. x The generation rate has decreased by 80%.

[0043] In some embodiments, the electromagnetic induction reforming device is a semi-enclosed furnace body, which is divided into a reaction zone, an expansion section and a gas-solid separation zone from top to bottom. The reaction zone is equipped with an induction coil that provides energy for the reforming reaction.

[0044] In this embodiment, the reaction zone is located at the top of the electromagnetic induction reforming device and is the core area for the reforming reaction. It is the region where high-temperature coal gas is mixed with coal and then subjected to electromagnetic induction heating for reforming. The expansion section is located below the reaction zone and extends outwards; the reformed coal gas is discharged from the side, serving as a transition and guiding element. The gas-solid separation zone is located below the expansion section, i.e., at the bottom of the device, and its main function is to separate the high-temperature coal gas generated by the reaction from the coal ash produced after the reforming reaction.

[0045] In some embodiments, the bottom of the electromagnetic induction reforming device is provided with a slag discharge port for discharging the coal ash and reaction slag generated after gas-solid separation.

[0046] In some embodiments, the system further includes a green electricity supply unit, which is connected via circuitry to the electromagnetic induction reforming device and the plasma heating device, respectively, to provide energy for the reforming reaction and final heating.

[0047] In some embodiments, the preheating device is a heat exchange gas heater or a heat exchange hot air furnace, the heat source of which comes from high-temperature metallurgical waste gas outside the system, and is used to recover waste heat to preheat the gas at the top of the furnace.

[0048] In some embodiments, such as Figure 2 As shown, the plasma heating device mainly consists of a graphite electrode, a water-cooled bottom electrode, a reaction chamber, a feeding system, a slag outlet, and a product outlet.

[0049] In this embodiment, the graphite electrode serves as the upper electrode, vertically mounted at the top of the reaction chamber. The water-cooled bottom electrode is located at the bottom of the reaction chamber, opposite to the graphite electrode. The reaction chamber, the main space for material reaction, is located between the graphite electrode and the water-cooled bottom electrode. The slag outlet is located at the bottom of the reaction chamber, adjacent to the water-cooled bottom electrode. The product outlet is located on the side of the reaction chamber, used to discharge the gaseous products generated in the reaction (such as CO, CO2, H2, etc.) from the device.

[0050] The following specific embodiments further illustrate this solution.

[0051] Example 1 A top gas recirculation reforming process includes the following steps: S1. 430 m 3 After dust removal, the top gas of the HyCROF carbon circulation blast furnace is transported to a heat exchanger hot blast stove for heating to obtain high-temperature gas; the inlet gas temperature of the heat exchanger gas heater is 100℃ and the outlet gas temperature is 1200℃. S2. The high-temperature gas obtained from the outlet of the heat exchanger hot blast stove is maintained at 1200℃ and transported to the electromagnetic induction heating gas reforming unit. At the same time, high-volatile bituminous coal is added. After heating and reforming, reducing gas containing CO and H2 is obtained at a temperature of 1000℃. The reducing gas contains 60%~90% CO, 35%~45% H2, and 0~5% CO2+H2O. S3. The reducing gas obtained at the outlet of the electromagnetic induction heating gas reforming device is kept at a temperature of 1000℃ and transported to the plasma heating device to obtain high-temperature reducing gas at a temperature of 1600℃, which is then injected into the furnace from the lower hearth tuyeres of the carbon cycle blast furnace. S4. The high-temperature reducing gas from step S3 enters the carbon-circulating blast furnace. The gas formed in the tuyeres swirling zone transfers heat and mass from bottom to top and is then discharged from the carbon-circulating blast furnace. The resulting top gas is then recycled into the heat exchange heating furnace, realizing the gas circulation injection from hot blast stove preheating to induction furnace reforming to plasma furnace heating.

[0052] Example 2 A furnace top gas circulation reforming process is the same as in Example 1, except that high volatile bituminous coal is replaced with anthracite.

[0053] Example 3 A blast furnace gas circulating reforming system comprises a closed material flow circulation loop, including a blast furnace body, a preheating device, an electromagnetic induction reforming device, and a plasma heating device connected sequentially along the material flow direction. The blast furnace body's top gas outlet is connected via a pipeline to the inlet of the preheating device for conveying the top gas to the preheating device. The preheating device's outlet is connected via a pipeline to the gas inlet at the top of the electromagnetic induction reforming device for conveying the preheated high-temperature gas to the reforming device. The electromagnetic induction reforming device has a coal inlet for adding coal to the device. The electromagnetic induction reforming device's gas outlet is connected via a pipeline to the inlet of the plasma heating device for conveying the reformed reducing gas to the heating device. The plasma heating device's outlet is connected via a pipeline to the tuyeres at the bottom of the blast furnace body for injecting the final high-temperature reducing gas back into the blast furnace. The system generates top gas from the blast furnace body. The gas flows sequentially through a preheating device, an electromagnetic induction reforming device, and a plasma heating device for upgrading and heating before returning to the blast furnace body, forming a closed-loop material flow of the top gas. The electromagnetic induction reforming device is divided into a reaction zone, an expansion section, and a gas-solid separation zone from top to bottom. The reaction zone is equipped with an induction coil to provide energy for the reforming reaction. The bottom of the electromagnetic induction reforming device is equipped with a slag discharge port to discharge the coal ash and reaction slag produced after gas-solid separation. The system also includes a green electricity supply unit, which is connected to the electromagnetic induction reforming device and the plasma heating device through circuits to provide energy for the reforming reaction and final heating. The preheating device consists of a heat exchange gas heater and a heat exchange hot blast stove, with its heat source coming from high-temperature metallurgical waste gas outside the system, used to recover waste heat to preheat the top gas. The plasma heating device uses graphite electrodes and is equipped with a water-cooled bottom electrode and a bottom slag discharge port.

[0054] Comparative Example 1 A furnace top gas circulation reforming process is the same as in Example 1, except that an electromagnetic induction heating gas reforming device is not used.

[0055] Testing and Evaluation The high-volatile bituminous coal and anthracite used in Examples 1 and 2 were analyzed. The industrial and elemental analysis results of the high-volatile bituminous coal and anthracite are shown in Table 1. The composition of the top gas and reducing gas in Example 1 is shown in Table 2. The composition of the top gas and reducing gas in Example 2 is shown in Table 3. The composition of the top gas and reducing gas in Comparative Example 1 is shown in Table 4. The blast furnace parameters of different examples and comparative examples are shown in Table 5.

[0056] Table 1. Industrial and elemental analysis results (ad, wt. %) of high volatile bituminous coal and anthracite. Table 2 Gas composition before and after reforming in Example 1 Table 3 Gas composition before and after reforming in Example 2 Table 4. Gas composition before and after reforming in Comparative Example 1 Table 5 Comparison of parameters of different blast furnaces In Example 1, the CO content of the outlet gas from the electromagnetic induction furnace is between 60% and 70%, and the H2 content is between 35% and 39%. The sum of the CO2 and H2O contents is less than 5%, meeting the composition requirements for circulating injection at the tuyeres of a carbon-cycle blast furnace. High-volatile bituminous coal is added during the gas reforming process in the electromagnetic induction furnace. High-volatile bituminous coal has a high carbon content and a long, stable flame during combustion, making it suitable as a raw material for gas reforming. Its high calorific value combined with the high efficiency of electromagnetic induction heating can further optimize energy utilization, reduce energy consumption per unit output, improve gasification efficiency, and further reduce system resource consumption. The reducing gas enters the plasma heating device as a reaction medium, interacting with the high-temperature, highly reactive particles of the plasma to accelerate the chemical reaction. Plasma heating eliminates the need for oxygen-assisted combustion, reducing nitrogen oxides (NOx). x The hydrocarbons in the reduced coal gas are more thoroughly cracked at high temperatures, reducing carbon monoxide (CO) and particulate matter emissions.

[0057] Although the consumption of high-volatile bituminous coal (such as lignite and long-flame coal) increases by about 20%, its high volatile characteristics allow for a richer input of gas components and volume into the system, thereby reducing the demand for top gas reforming by about 23% and ultimately reducing green energy consumption in plasma reforming and heating processes by 11%. From an economic perspective, since the market price of high-volatile coal powder is much lower than that of anthracite, the cost of coal powder in the process can still be reduced despite the increased demand. It should be noted that the gas provided by the high-volatile coal powder itself increases the amount of gas exported, thus increasing the carbon emissions per unit of molten iron by 104 kg; however, due to its hydrogen-rich characteristics (H2 volume fraction of about 26%), the exported gas exhibits stronger economic competitiveness in the co-production of methanol, olefins, and other organic chemicals in steelmaking, effectively offsetting the environmental costs brought about by the increase in carbon emissions.

[0058] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A top gas recycle reforming process, characterized in that, The method comprises the following steps: S1. Heating the blast furnace top gas generated by a blast furnace to 1000-1200℃ to obtain high-temperature gas; S2. Mixing the high-temperature gas with coal and performing electromagnetic induction heating of the gas to generate a reduction gas containing CO and H2 at 900-1000℃; S3. Plasma heating of the reduction gas to 1400-1800℃ to obtain high-temperature reduction gas; S4. Recycling the high-temperature reduction gas to the lower part of the blast furnace for cyclic treatment.

2. The top gas recycle reforming process according to claim 1, characterized in that, The blast furnace top gas has the following components: CO volume content 30%-45%, H2 volume content 20%-30%, CO2 volume content 15%-25%, H2O volume content 10%-20%, N2 volume content <5%.

3. The top gas recycle reforming process according to claim 1, characterized in that, The reduction gas has the following components: CO volume content 60%-90%, H2 volume content 30%-45%, and the sum of CO2 and H2O volume content <5%.

4. The top gas recycle reforming process according to claim 1, characterized in that, The coal has the following components: fixed carbon mass content 50%-55%, moisture mass content 15%-18%, ash mass content 4%-7%, and volatile matter mass content 28%-32%; the volatile matter has the following components: CO2 mass content 10%, CO mass content 40%, CH4 mass content 15%, H2 mass content 30%, and N2 mass content 5%.

5. The top gas recycle reforming process according to claim 1, characterized in that, Before the heating treatment in step S1, the blast furnace top gas is further subjected to dust removal and / or dehydration.

6. The top gas recycle reforming process according to claim 1, characterized in that, The energy required for heating in step S1 is provided by high-temperature metallurgical waste gas heat exchange; the energy required for electromagnetic induction heating of the gas reforming reaction is provided by green electricity and / or oxidation reaction inside the reaction system; the energy required for plasma heating is provided by green electricity; and the heat in the blast furnace is provided by the high-temperature reduction gas.

7. The top gas recycle reforming process according to claim 1, characterized in that, Between steps S2 and S3, the product of the electromagnetic induction heating of the gas reforming reaction is further subjected to gas-solid separation.

8. A top gas recycle reforming system for carrying out the process according to any one of claims 1 to 7, characterized in that The system comprises a blast furnace body, a preheating device, an electromagnetic induction reforming device, and a plasma heating device connected in sequence along the material flow direction; the blast furnace body top gas outlet is connected to the preheating device inlet through a pipeline; the preheating device outlet is connected to the electromagnetic induction reforming device top gas inlet through a pipeline; the electromagnetic induction reforming device is provided with a coal inlet for adding coal into the device; the electromagnetic induction reforming device gas outlet is connected to the plasma heating device inlet through a pipeline; and the plasma heating device outlet is connected to the blast furnace body lower tuyere through a pipeline.

9. The top gas recycle reforming system of claim 8, wherein, The electromagnetic induction reforming device is internally divided into a reaction zone, an expansion section, and a gas-solid separation zone from top to bottom, wherein the reaction zone is provided with an induction coil for providing energy for the reforming reaction.

10. The top gas recycle reforming system of claim 8, wherein, The plasma heating device adopts a graphite electrode and is equipped with a water-cooled bottom electrode and a bottom slag outlet.

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