Smelting method based on blast furnace oxygen-free metallurgy, electrified heating, and reformed coal gas

Abstract

Disclosed in the present invention is a smelting method based on blast furnace oxygen-free metallurgy, electrified heating, and reformed coal gas. The method is implemented in three steps of a basic scheme, a transition scheme, and a final scheme, and comprises the following devices: a metallurgical blast furnace, a batching device, a dust-containing coal gas dehydration treatment device, a coal gas CO2 reforming device, a coal gas heat exchange device, a nitrogen source device, a coal injection device, an electrified heating device, a coal gas pressurizing device, a composite tuyere device, a furnace body blowing device, residual coal gas treatment devices, a blow source device, and an oxygen source device, wherein the residual gas treatment devices comprise a power generation device, a boiler, or a fuel gas device, a coal gas holder, a gas storage device, and a chemical device. The gas switching function in the three steps of the method is implemented by 13 cutoff devices.

Description

A method for smelting blast furnace oxygen-free metallurgy by electrification heating and reforming coal gas Technical Field

[0001] The invention belongs to the field of ferrous metallurgy, and relates to a method for smelting blast furnace oxygen-free metallurgy by electrified heating reformed coal gas, which is applicable to the blast furnace ironmaking process. Background Art

[0002] Currently, 90% of the world's pig iron is produced using the traditional blast furnace ironmaking process. In this process, coke and pulverized coal are the primary fuels. Iron-containing charge material and coke are charged from the top of the furnace, while hot air and pulverized coal are injected through the hearth tuyeres. This high solid fuel consumption leads to high greenhouse gas CO2 emissions. To address these issues, a new ironmaking process using oxygen blast and top gas recirculation has been developed. To overcome the drawbacks of insufficient bosh gas after full oxygen production and the upper cooling and lower heating process, this process removes CO2 from the top gas, preheats it to 900-1300°C, and then recirculates it back to the blast furnace. This process overcomes the high CO2 emissions associated with traditional blast furnaces. However, the cost of removing CO2 from the top gas is high, as is the preheating process. Furthermore, the recirculation of the top gas back into the blast furnace reduces the amount of external gas supplied, negatively impacting the gas balance of the entire steel enterprise. Summary of the Invention

[0003] In order to solve the problems of large-scale use of coke in traditional blast furnaces, serious environmental pollution, high carbon emissions, and high costs for CO2 removal and gas preheating in oxygen blast furnaces, the present invention provides a method for smelting blast furnace oxygen-free metallurgy electrified heating reforming gas. This method can use no or minimal coke, has a certain greenhouse gas CO2 emission reduction effect, can achieve the reduction of coke and increase of coal in the blast furnace production process, improve the energy structure of the ironmaking process, and stabilize the gas balance of steel enterprises.

[0004] The technical solution adopted by the present invention is: a method for smelting blast furnace oxygen-free metallurgical electrified heating reforming coal gas, the main equipment components are as follows: a metallurgical blast furnace, a charging device, a coal gas dust dehydration treatment device, a CO2 reforming device in the coal gas, a coal injection device, an electric heating device, a coal gas heat exchange device, a residual coal gas treatment device, a coal gas pressurizing device, a coal gas blowing device, an air blast source device, an oxygen source device, and a nitrogen source device. The gas switching function of this method is the 13 main cutting devices used.

[0005] The electric heating device specifically includes one or a combination of a DC non-transferred arc plasma torch, a DC transferred arc plasma torch, an AC arc plasma torch, a radio frequency plasma torch, a microwave plasma torch, etc. The coal gas uses a plasma generator as a heat source for heating. The plasma torch power ranges from 5 to 15 MW, the temperature can reach 2000 to 10000°C, and the jet velocity exceeds 200 m / s.

[0006] The composite tuyere is a composite copper sleeve injection, with a wear-resistant and high-temperature resistant liner provided inside, a gas channel provided inside the wear-resistant and high-temperature resistant liner, and the high-temperature gas enters the furnace through the gas channel inside the wear-resistant and high-temperature resistant liner. An oxygen channel is also provided on one side of the interior of the copper sleeve, and one end of the oxygen channel is connected to an oxygen supply pipe to realize the composite injection of high-temperature gas, oxygen and coal powder.

[0007] The residual gas processing device specifically includes a gas cabinet, a power generation device, a boiler, a chemical device or other gas device.

[0008] 1. Specific Basic Plan: Implementation of this plan first requires confirming the open and closed states of 13 primary shutoff devices. As shown in Flowchart 1, the open states are: a, e, j, L, and m; the closed states are: b, c, d, f, g, h, i, and k. The shutoff devices are airtight, with zero gas leakage in the closed state. Shutoff devices c, d, and k are heat-resistant, utilizing cooling media (soft water, demineralized water, or air) and can withstand temperatures up to 1400°C. Preferred shutoff devices a, b, e, j, f, g, h, i, L, and m can withstand temperatures between 80°C and 300°C.

[0009] Specifically, the basic scheme of the present invention is used to realize the final scheme of a method for smelting reformed coal gas by electrified heating in a blast furnace for oxygen-free metallurgy, providing basic heat and reducing agent for smelting reduction in the blast furnace. The blast furnace is used as metallurgical equipment, and the charge is added into the furnace by the charging device on the furnace top. The charge includes ore and coke. The composite tuyere at the lower part of the furnace cylinder blows in blast air supplied by the blast source device after being heated by the electric heating device. At the same time, the coal powder provided by the coal injection device transported by N2 from the nitrogen source is sprayed into the composite tuyere into the furnace. At this time, the oxygen with an oxygen content of 85-99% provided by the oxygen source device can also be sprayed into the furnace through the composite tuyere. The composite tuyere has the function of inputting through a multi-media input hole channel. The high-temperature blast burns with the coal powder, coke and oxygen to generate heat and reducing gas. An oxidation-reduction reaction occurs in the furnace to generate reducing coal gas, which takes away oxygen from the ore to generate qualified molten iron and by-product slag. At the same time, the generated coal gas is dedused and dehydrated at the furnace top and then enters the residual coal gas treatment device.

[0010] Specifically, the ore blending structure mainly adopts alkaline ore, acidic ore and natural lump ore. The solid fuel ratio is 370-450kg / t coke ratio, 100-150kg / t coal ratio, and the top gas generation volume is 1500-1650Nm 3 / t, blast volume 1200-1350Nm 3 / t, oxygen enrichment 30-50Nm 3 / t, blast temperature 1200-1300℃, bosh gas flux on its cross-sectional area is 55-60m2 / Nm 3 / , the volume percentage of furnace gas composition CO+H2 is 39-42%, and the volume percentage of N2 is 58-61%.

[0011] Specifically, the basic scheme controls parameters from furnace opening to entering the stable zone: the blast furnace condition is stable and smooth, the furnace temperature is stable, the pig iron [Si]=0.35-0.5%, the slag basicity is appropriately controlled at R2=1.05-1.18 times, there is no hanging material, the actual hourly material rate is equal to the theoretical material rate, and on this basis, it is controlled to enter the transition scheme within 5-8 days. At the end of this stage, the coke ratio is 370kg / t and the coal ratio is 150kg / t.

[0012] II. Specific Transition Plan: This plan requires switching between the open and closed states of the 13 main disconnecting devices in the basic plan. As shown in Flowchart 1, disconnecting device a is switched from open to closed; disconnecting devices e, j, L, and m remain in the open state of the basic plan; disconnecting devices c, f, g, h, and i remain in the closed state of the basic plan; and disconnecting devices b, d, and k are switched from closed to open. This switching operation must be performed while the blast furnace is idle.

[0013] Specifically, the transition scheme of the present invention is used to ensure the realization of the final solution of a method for smelting blast furnace oxygen-free metallurgy electrified heating reforming gas, and to achieve the lowest coke ratio under the condition of continuously reducing the coke ratio, while providing the basic heat for switching to the final solution blast furnace smelting reduction and the raw gas volume of the required reducing agent. With the blast furnace as the metallurgical equipment, the furnace charge is added into the furnace by the charging device on the top of the furnace. The furnace charge includes ore and coke. The oxygen with an oxygen content of 85-99% provided by the oxygen source device is sprayed into the furnace using the composite tuyere. At the same time, the coal powder provided by the coal injection device transported by N2 from the nitrogen source is sprayed into the furnace through the composite tuyere. The oxygen burns with the coal powder and coke to generate heat and reducing gas. An oxidation-reduction reaction occurs in the furnace to generate reducing coal gas, which takes away oxygen from the ore and generates qualified molten iron and by-product slag. The generated coal gas is dehydrated by the furnace top dust collector and then divided into two paths. One path of the furnace top coal gas passes through the electric heating device. After being heated, it enters the CO2 reforming device, and the coal powder provided by the coal injection device transported by N2 from the nitrogen source is sprayed into the CO2 reforming device. The CO2 in the coal gas reacts with the C in the coal powder to generate the reducing agent CO. The reducing agent at this time merges with the original reducing agent in the coal gas at the top of the furnace in the CO2 reforming device and flows out from the top. The outflowing reducing agent with reducing properties is divided into two parts, one part is sprayed into the furnace by the composite device of the tuyere, and the other part is sprayed into the furnace by the furnace body; the coal gas at the top of the furnace enters the power generation device or the gas cabinet of the residual coal gas treatment device through another route after the dust removal and dehydration at the top of the furnace for energy-saving utilization or storage.

[0014] The coal injection device has the ability to simultaneously transport coal powder to the blast furnace and the CO2 reforming device, and the coal powder particle size is ≯-200 mesh.

[0015] The high-temperature reducing agent is sprayed into the furnace, undergoes redox reaction with the ore in the furnace, deprives oxygen from the ore, generates qualified molten iron and by-product slag, and has the effect of replacing coke in the furnace.

[0016] Specifically, the solid fuel coke is reduced from 370kg / t to 50kg / t, the coal ratio of the composite tuyere is 10-150kg / t, and the top gas generation volume is 1350-1400Nm 3 / t, oxygen content 0-220Nm 3 / t, the electric heating gas temperature is 1200-1400℃, and the top gas volume entering the CO2 reforming unit is 400-902Nm 3 / t, the reducing gas from the CO2 reforming unit is 574.3-1295.46Nm 3 / t, furnace body injection 100-350Nm 3 / t, composite tuyere spray 474.3-945Nm 3 / t, the coal injection rate of the CO2 reforming unit is 129.46-291.94kg / t, and the residual gas volume entering the pipe network is 477-997Nm 3 / t, the bosh gas flux is 55-60m 2 / Nm 3 The volume percentage of the furnace gas is 94-96% CO+H2 and 4-6% N2. The volume percentage of the top gas is 52-55% CO+H2 and 40-43% CO2.

[0017] Specifically, the parameters of the transition plan from the basic plan to the stable zone are controlled as follows: the blast furnace condition is stable and smooth, the furnace temperature is stable, the pig iron [Si]=0.4-0.55%, the slag basicity is appropriately controlled at R2=1.05-1.18 times, there is no hanging material, the actual hourly material rate is equal to the theoretical material rate, and on this basis, it is controlled for 3-5 days to enter the final plan.

[0018] Final Specific Plan: This plan involves switching operations between the open and closed states of the 13 primary disconnecting devices in the transition plan. As shown in Flowchart 1, disconnecting device a remains closed; disconnecting devices b, d, and k remain open; disconnecting devices e, j, L, and m switch from open to closed; and disconnecting devices c, f, g, h, and i switch from closed to open. Switching operations are preferably performed at the end of the blast furnace transition plan, or, for inherent safety reasons, while the blast furnace is idle.

[0019] Specifically, the final solution of the present invention is a method for blast furnace oxygen-free metallurgy electrification heating reforming coal gas smelting. The coke ratio has reached the lowest level, and it only provides the skeleton and molten iron carburizing and Si, Mn, P, and desulfurization in the furnace. The heat required for reduction is provided by the coal gas electric heating device, and the reducing agent is provided by the coal injection amount of the coal gas entering the CO2 reforming device in the transition to the final solution. A blast furnace is used as metallurgical equipment, and the charge is added into the furnace by the charging device on the top of the furnace. The charge includes ore and minimum coke. The oxygen source device is stopped, and the coal powder provided by the N2 conveying coal injection device of the nitrogen source is sprayed into the CO2 reforming device. All the top gas enters the CO2 reforming device, and the CO2 in the gas reacts with the C in the coal powder in the CO2 reforming device to generate the reducing agent CO. The reducing agent at this time is combined with the original reducing agent in the top gas in the CO2 reforming device and then flows out from the top. The outflowing reducing agent with reducing properties is divided into three parts. The first part is sprayed into the furnace by the composite device of the tuyere, the second part is sprayed into the furnace by the furnace body, and the third part is the surplus high-temperature reducing agent of the blast furnace. After the heat is transferred to the top branch gas through the gas heat exchange device, it enters the gas cabinet or chemical device of the residual gas processing device for energy-saving storage or chemical carbon fixation utilization, so as to achieve zero-carbon metallurgy with full utilization of CO2.

[0020] Furthermore, the branched coal gas is divided into two branches before the top coal gas enters the CO2 reforming device. One branch directly enters the CO2 reforming device, and the other branch goes to the coal gas heat exchange device to exchange heat with the remaining high-temperature coal gas after the CO2 reforming device, and is then mixed back into the first branch of the top coal gas that directly enters the CO2 reforming device through the gas pressurizing device, thereby ensuring the heat recovery of the remaining high-temperature coal gas after reforming, and also providing the process conditions of the coal gas temperature for the next chemical carbon fixation process. At the same time, due to the heat recovery, the power consumption of the electric heating device can be reduced, the electricity consumption can be reduced, or the number of electric heating devices can be reduced.

[0021] The coal injection device in this scheme stage only has the function of simultaneously delivering coal powder to the CO2 reforming device. The cutting device e is in a closed state, and the coal powder particle size is ≯-200 mesh.

[0022] The high-temperature reducing agent is sprayed into the furnace, undergoes redox reaction with the ore in the furnace, removes oxygen from the ore, generates qualified molten iron and by-product slag, and has the effect of replacing coke and coal powder in the furnace.

[0023] Specifically, the solid fuel coke is 50kg / t, and the top gas generation volume is 1350-1400Nm 3 / t, oxygen content 0Nm 3 / t, the temperature of electrically heated gas is 1200-1400℃, and the amount of top gas entering the CO2 reforming unit is 1379Nm 3 / t, reducing gas from CO2 reforming unit 1979Nm 3 / t, heat recovery of residual high temperature gas after reforming 0.8-1.2GJ, furnace body injection 200-350Nm 3 / t, composite tuyere injection 750-945Nm 3 / t, the coal ratio of the CO2 reforming unit is 446kg / t, and the residual gas volume entering the pipe network is 684Nm 3 / t, the bosh gas flux is 55-60m 2 / Nm 3 The volume percentage of the furnace gas is 94-96% CO+H2 and 4-6% N2. The volume percentage of the top gas is 52-55% CO+H2 and 40-43% CO2.

[0024] Specifically, the parameters of the final solution are controlled as follows: the blast furnace condition is stable and smooth, the furnace temperature is stable, the pig iron [Si] is 0.35-0.45%, the slag basicity is appropriately controlled at R2=1.05-1.15 times, there is no hanging material, the actual hourly material rate is equal to the theoretical material rate, and finally qualified molten iron and by-product slag are generated. At the same time, the by-product residual coal gas is generated for energy-saving storage or chemical carbon fixation utilization in chemical equipment, so as to achieve a zero-carbon metallurgical blast furnace oxygen-free metallurgy electrification smelting method that fully utilizes CO2.

[0025] Beneficial effects of the present invention:

[0026] 1. To address the problems of traditional blast furnaces using large amounts of coke, resulting in severe environmental pollution and high carbon emissions, as well as the high costs of CO2 removal and gas preheating in oxygen-blast blast furnaces, this invention provides a metallurgical electrification method that eliminates oxygen in the blast furnace and reforms CO2 with top gas. This method eliminates or minimizes the use of coke and achieves a certain degree of greenhouse gas CO2 emission reduction. This method reduces coke consumption and increases coal consumption during blast furnace production, improves the energy structure of the ironmaking process, stabilizes the gas balance of steel enterprises, and provides high-quality feed gas for the chemical industry.

[0027] 2. The surplus high-temperature reducing agent in the blast furnace of the present invention transfers heat to the branch gas on the furnace top through the gas heat exchange device, and then enters the gas cabinet or chemical device of the residual gas processing device for energy-saving storage or chemical carbon fixation utilization, thereby achieving zero-carbon metallurgy with full utilization of CO2.

[0028] 3. The present invention recovers heat from the remaining high-temperature coal gas after reforming, providing process conditions for the coal gas temperature for the next chemical carbon fixation process. At the same time, the heat recovery of 0.8-1.2GJ can reduce the power consumption of the electric heating device, reduce electricity consumption or reduce the number of electric heating devices.

[0029] 4. On the basis of maintaining the smooth operation of the furnace condition, the present invention has flexible adjustment parameters, can step-by-step increase the amount of gas injected into the furnace hearth and furnace body, improve the coal injection ratio of the CO2 reforming furnace, increase the power of the gas electric heating on the furnace top, and step-by-step reduce the coke ratio, ultimately achieving zero oxygen consumption at the tuyere. The coke ratio only includes the carbon consumption for carburizing of molten iron and direct reduction of elements such as Mn, Si, and P, thereby achieving the lowest coke consumption.

[0030] 5. The present invention provides heat through electric heating to realize the reaction of CO2 with C in coal powder in the reforming device, and the temperature of the reducing agent after reforming can reach 1300-2300℃. In addition, electric heating can completely use green electricity under the condition of reduced green electricity cost. Compared with traditional blast furnaces, the present invention reduces carbon emissions by 92.6%, and can realize green ironmaking. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG1 is a process flow diagram of the method of the present invention;

[0032] In the figure: 1 - Metallurgical blast furnace, 2 - Charging device, 3 - Coal gas dust dehydration treatment device, 4 - Coal gas CO2 reforming device, 5 - Coal gas heat exchange device, 6 - Nitrogen source device, 7 - Coal injection device, 8 - Electric heating device, 9 - Coal gas pressurization device, 10 - Composite tuyere device, 11 - Furnace body injection device, 12-14 are all residual gas processing devices, specifically 12 is the power generation device and boiler within the residual gas processing device, 13 is the gas cabinet and gas storage device within the residual gas processing device, 14 is the chemical device within the residual gas processing device, 15 - Blast source device, 16 - Oxygen source device. To distinguish them from the device labels, the 13 cutting devices are labeled: a, b, c, d, e, f, g, h, i, j, k, L, m. DETAILED DESCRIPTION

[0033] The following will be combined with Figure 1 of the embodiment of the present invention to clearly and completely describe the technical solutions in the embodiment of the present invention. Obviously, the embodiment described is only a part of the embodiment of the present invention, not all the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] Please refer to Figure 1. A method for smelting blast furnace oxygen-free metallurgical electrified heating reformed coal gas is implemented through three steps: a basic scheme, a transition scheme, and a final scheme. The equipment of this method is as follows: a metallurgical blast furnace, a charging device, a coal gas dust dehydration treatment device, a coal gas CO2 reforming device, a coal gas heat exchange device, a nitrogen source device, a coal injection device, an electric heating device, a coal gas pressurization device, a composite tuyere device, a furnace body blowing device, and a residual coal gas treatment device, wherein the residual coal gas treatment device includes a power generation device, a boiler, or a gas device, a gas cabinet, a gas storage device, a chemical device, a blast source device, and an oxygen source device. The gas switching function between the three steps of this method is completed by the 13 cutting devices used.

[0035] First, implement the first step of the basic plan: specifically confirm the open and closed status of the 13 main cutting devices, as shown in the flow chart 1, adjust the cutting devices a, e, j, L, and m to the open state, and adjust the cutting devices b, c, d, f, g, h, i, and k to the closed state. The charge of the blast furnace 1 is added into the furnace by the charging device 2 on the top of the furnace. The charge includes ore and coke. The ore matching structure mainly adopts alkaline ore, acidic ore, and natural lump ore. The coke ratio is 370-450kg / t. The composite tuyere 10 multi-media input hole channel at the bottom of the furnace is used to blow in the blast supplied by the blast source device 15 heated by the electric heating device. The blast temperature is 1200-1300℃, and the blast volume is 1200-1350Nm 3 / t, and at the same time, the pulverized coal provided by the coal injection device 7 is transported by the N2 of the nitrogen source 6, with a coal ratio of 100-150kg / t, and is sprayed into the furnace through the composite tuyere 10, and the oxygen source device 16 provides oxygen with an oxygen content of 85-99% and an oxygen enrichment of 30-50Nm 3 / t, and at the same time, it is sprayed into the furnace through the composite tuyere 10, and the high-temperature blast burns with the coal powder, coke and oxygen to generate heat and reducing gas, and an oxidation-reduction reaction occurs in the furnace to generate reducing gas, which takes away oxygen from the ore and generates qualified molten iron with [Si] = 0.35-0.5% and a by-product slag with alkalinity R2 = 1.05-1.18 times, and at the same time generates 1500-1650Nm 3 / t of coal gas is dedusted and dehydrated by the furnace top and then enters the residual coal gas treatment devices 12 and 13. This plan is controlled for 5-8 days, and at the end of the process, the coke ratio is 370kg / t and the coal ratio is 150kg / t.

[0036] The second step is to implement the transition plan: This plan requires confirming the open and closed states of the 13 key shutoff devices in the basic plan. Based on the process requirements for gas heating flow, these devices will be switched or maintained unchanged. As shown in Flowchart 1, shutoff device a will be switched from open to closed; shutoff devices e, j, L, and m will remain in the open state of the basic plan; shutoff devices c, f, g, h, and i will remain in the closed state of the basic plan; and shutoff devices b, d, and k will be switched from closed to open. This switching operation will be performed while the blast furnace is idle, ensuring inherent safety.

[0037] The charge ore and 50-370kg / t of coke of blast furnace 1 are added into the furnace by the charging device 2 on the top of the furnace. The oxygen source device 16 provides oxygen with an oxygen content of 85-99%, and the oxygen content is 0-220Nm 3 / t, is sprayed into the furnace by the composite tuyere device 10, and at the same time, the N2 of the nitrogen source device 6 is used to transport the coal powder 10-150kg / t provided by the coal injection device 7 and sprayed into the furnace to generate 1379Nm 3 / t of coal gas is divided into two routes after dust removal and dehydration at the furnace top, one route is 400-902Nm 3 / t of top gas is heated by electric heating device 8 and enters CO2 reforming device 4. Pulverized coal (129.46-291.94 kg / t) is supplied by coal injection device 7 through N2 transport of nitrogen source device 6 and injected into CO2 reforming device 4. CO2 in gas reacts with C in pulverized coal to generate reducing agent CO. The reducing agent at this time is combined with the original reducing agent in the top gas in CO2 reforming device and then flows out from the top. The outflowing reducing agent has a reducing capacity of 574.3-1295.46 Nm 3 / t of reducing agent is divided into two parts, one part is 474.3-945Nm 3 / t of reducing agent is sprayed into the furnace by the composite device 10 of the tuyere, and the other part is 100-350Nm 3 / t reducing agent is sprayed into the furnace by the furnace body blowing device 11; the top gas is another 477-997Nm 3 / t residual gas enters the power generation device or gas tank of the residual gas treatment device 12 or 13 for energy-saving utilization or storage. The oxygen injected by the composite tuyere device burns with the coal powder and coke, generating heat and reducing gas. An oxidation-reduction reaction occurs in the furnace, generating reducing gas, which deprives oxygen from the ore, generating qualified molten iron with [Si] = 0.4-0.55% and a by-product slag with R2 = 1.05-1.18 times, and at the same time generating 1350-1400Nm 3 / t of coal gas is dedusted and dehydrated at the furnace top and then enters the residual coal gas treatment device. This plan is controlled for 3-5 days, at the end of which the coke ratio is 50kg / t and the coal ratio is 291.94kg / t.

[0038] The third step is to implement the final plan: This plan involves switching operations between the open and closed states of the 13 key shutoff devices in the transition plan. Operations are switched or maintained unchanged based on the gas heating flow direction required by the process. As shown in Flowchart 1, shutoff device a remains closed; shutoff devices b, d, and k remain open; shutoff devices e, j, L, and m switch from open to closed; and shutoff devices c, f, g, h, and i switch from closed to open. Switching operations are preferably performed at the end of the blast furnace transition plan, or, for inherent safety reasons, during the blast furnace inactivity phase.

[0039] The charge ore and minimum coke 50kg / t of blast furnace 1 are added into the furnace by the charging device 2 on the top of the furnace. The oxygen source device 3 is shut off by the m device to stop the oxygen amount 0Nm 3 / t, the N2 transport coal injection device 7 of the nitrogen source device 6 provides 446kg / t of coal powder to be injected into the CO2 reforming device 4, and the top gas is 1350-1400Nm 3 / t (in this case 1379Nm 3 / t) all enter the CO2 reforming device, where the CO2 in the gas reacts with the C in the pulverized coal to generate the reducing agent CO. The total amount of the reducing agent at this time and the original reducing agent in the gas at the top of the furnace is 1979Nm 3 / tAfter being combined in the CO2 reforming unit, it flows out from the top. The outflowing reducing agent with reducing properties is divided into three parts. The first part is 750-9450Nm 3 / t of reducing gas is injected into the furnace from the composite device 10 of the tuyere, and the second part is 200-350Nm 3 / t of reducing gas is injected into the furnace by the furnace body injection device 11, and the third part is the surplus 684Nm 3 / t high-temperature reducing agent, which transfers 0.8-1.2GJ of heat to the branch gas on the furnace top through the gas heat exchange device 5, and then enters the gas cabinet or chemical device of the residual gas processing device for energy-saving storage or chemical carbon fixation utilization, so as to achieve zero-carbon metallurgy with full utilization of CO2.

[0040] Furthermore, the branched coal gas is divided into two branches before the top coal gas enters the CO2 reforming device. One branch directly enters the CO2 reforming device, and the other branch goes to the coal gas heat exchange device to exchange heat with the remaining high-temperature coal gas after the CO2 reforming device, and is then mixed back into the first branch of the top coal gas that directly enters the CO2 reforming device through the gas pressurizing device, thereby ensuring the heat recovery of the remaining high-temperature coal gas after reforming, and also providing the process conditions of the coal gas temperature for the next chemical carbon fixation process. At the same time, due to the heat recovery, the power consumption of the electric heating device can be reduced, the electricity consumption can be reduced, or the number of electric heating devices can be reduced.

[0041] Specifically, the parameters of the final solution are controlled as follows: the blast furnace condition is stable and smooth, the furnace temperature is stable, the pig iron [Si] is 0.35-0.45%, the slag basicity is appropriately controlled at R2=1.05-1.15 times, there is no hanging material, the actual hourly material rate is equal to the theoretical material rate, and finally qualified molten iron and by-product slag are generated. At the same time, the by-product residual coal gas is generated for energy-saving storage or chemical carbon fixation utilization in chemical equipment, so as to achieve a zero-carbon metallurgical blast furnace oxygen-free metallurgy electrification smelting method that fully utilizes CO2.

[0042] In order to fully illustrate the innovation, creativity and practicality of this technology, the innovation, creativity and practicality of the present invention are further described in detail below with theoretical analysis of the embodiments. Example

[0043] 400m 3 Taking HyCROF as an example, all the HyCROF top gas (without decarburization) is introduced into the plasma to provide a heat source, and the top gas is completely reformed. At the same time, pulverized coal is introduced into the reforming furnace so that the CO2 in the gas is completely reformed into CO under a high-temperature environment. Then, a portion of the reformed high-temperature gas (basically CO components) is blown into the HyCROF tuyere and furnace body for oxygen-free smelting (the source of oxygen is Fe2O3 in the ore). The redox chemical reaction in the furnace is mainly indirect reduction, and the low-reactivity coke in the HyCROF furnace only plays a role in skeleton and carburizing, thereby achieving the lowest fuel consumption in the furnace and maximizing the purpose of carbon emission reduction; the other part is high-temperature gas, and after heat exchange, the gas temperature drops to room temperature and enters the gas holder pipeline network as chemical raw gas.

[0044] The embodiment of the present invention is based on 400m 3 The calculation is based on the heat of 10.07GJ / t of the optimal fuel ratio of the HyCROF stage, through the elimination of decarburization, oxygen-free smelting, all reforming of the HyCROF top gas, and the heating of the reformed gas as plasma heating as the process idea.

[0045] The specific approach and steps utilize a step-by-step calculation model. First, the theoretical top gas volume is calculated based on the consumption per ton of iron ore. This theoretical top gas volume is then divided into two parts for reforming. The first part determines the reformed top gas volume based on the amount of injected reducing gas. The second part calculates the remaining top gas volume from the first reformed part, which enters the gasholder network as chemical feedstock gas. Finally, the CO2 content in the two parts of the top gas requiring reforming is used to calculate pulverized coal consumption and heat consumption. Ultimately, the number of plasmas and power consumption are determined, and carbon emissions are compared with those of traditional blast furnaces, fully demonstrating the creativity and innovation of this technology.

[0046] S1: Determination of the boundary conditions for calculation (calculated by tons of iron)

[0047] Refer to the ultimate heat balance of 400-level HyCROF, setting:

[0048] The heat required in the HyCROF furnace is 10.07GJ / t iron; the gas utilization rate is 39-45%, and the direct reduction degree is r d =0.01, all the iron elements in the iron material entering the furnace exist in the form of Fe2O3.

[0049] S2: Calculation of top gas generation

[0050] S21: Determine the theoretical CO requirement for reducing Fe2O3 in the furnace;

[0051] Ton of iron requires Fe203t / t iron 1.36 tons of iron Fe203 requires the minimum reducing agent Nm 3 / t573.00 Reducing agent utilization rate%43.50 Reducing agent amount required for ton of iron Fe2O3 Nm 3 / t1317.24

[0052] Calculation Notes:

[0053] (1) The amount of Fe2O3 in the ore required to produce 1 ton of molten iron: converted according to the molecular formula Fe2O3, Fe2O3=(1-4.5% / 100) / (112 / 160)=1.36t / t iron;

[0054] (2) Minimum amount of CO required to reduce 1.36t Fe2O3: According to the chemical equation Fe2O3+3CO=2Fe+3CO2, 1molFe2O3 requires 3molCO to reduce 2mol of elemental iron. The amount of CO = (1.36*1000 / 160)*3*22.4=573 Nm 3 / t;

[0055] (3) Considering the CO utilization rate in the furnace is 43.5%, the actual amount of CO reducing agent required per ton of iron is: =573 / 0.435=1317.24 Nm 3 / t;

[0056] S22: Calculation of reducing agent CO demand

[0057] Direct reduction carbon consumption kg / t6.86 Direct reduction carbon consumption CO production Nm 3 / t21.78 tons of iron Fe2O3 requires reducing agent Nm 3 / t1295.46

[0058] Calculation Notes:

[0059] (1) The amount of CO produced by direct reduction of carbon in the furnace is 6.87 kg / t according to the content of Mn, Si, and P in the molten iron and the direct reduction degree of C in the molten iron; the amount of CO produced by coal gas is 21.78 Nm 3 / t

[0060] (2) The amount of CO injected into the furnace from the tuyere: 1317.24-21.78 = 1295.46Nm 3 / t

[0061] S23: Determination of the amount and composition of the top gas generated after the redox reaction in the furnace

[0062] Top gas composition

[0063] Total content of gas components CO+H2CO2N2% 53.9441.534.53100 Total gas volume m 3 / tiron744.2573.062.51379.74

[0064] Calculation Notes:

[0065] Theoretical furnace top gas volume = 1317.24 + coal injection nitrogen 25 + (furnace top nitrogen volume + safety) 37.5 = 1379.74Nm 3 / t.

[0066] S24: Determination of injection volume after 100% reforming of top gas and raw gas for chemical utilization

[0067]

[0068] Calculation Notes:

[0069] (1) After the HyCROF top gas is reformed in the reforming furnace (plasma heating + pulverized coal injection), the main reaction formula is: C + CO2 = 2CO; that is, 1 mol CO2 can be reduced to 2 mol CO.

[0070] (2) Based on this calculation, 100% top gas (1379.74m 3 / t)The amount of reducing gas produced after reforming: 744.2+573.0*2 +62.5= 1890 +62.5 = 1952.5 Nm 3 / t.

[0071] (3) The amount of reducing gas (CO + H2) + N2 injected into the furnace is: 1295.46 + 35 Nm 3 / t; converted to the top gas volume before reforming 902 Nm 3 / t;

[0072] (4) The remaining high-temperature reducing gas volume (CO+H2) + N2 is: 595 + 27.5 Nm 3 / t, enters the pipeline network after heat exchange and can be used to replace coal chemical raw materials and other fields, which is converted into 477 Nm of top gas before reforming.3 / t.

[0073] (5) The amount of top gas before injection into the furnace for reforming is 902 Nm 3 / t of CO2 requires 292kg / t of pulverized coal, and the remaining top gas volume is 477 Nm 3 / t of CO2 requires 154kg / t of coal powder.

[0074] S3: Calculation of heat capacity of electrically heated plasma

[0075] S31: Boundary conditions:

[0076] (1) Coal used in gas reforming reaction: calorific value 23MJ / kg; carbon content 72% (mass fraction);

[0077] (2) The heat required for C+CO2=2CO is 166.2kJ / mol; C+H2O=CO+H2133.1kJ / mol.

[0078] (3) Specific heat capacity of CO gas at 100°C: 1.30 kJ / Nm 3 .℃, CO calorific value: 12707kJ / Nm 3

[0079] (4) Molten iron output: 80t / h, plasma 5MW ton iron heat load / GJ / t=0.145.

[0080] S32: Heat required for injecting reducing agent into the furnace

[0081] Total heat demand for reaction in the furnace GJ / t 10.07 Injected coal (292kg / t) Reforming reaction heat consumption GJ / t 2.87 Injected coal gas (1295.46 + 35) Nm3 / t Calorific value GJ / t 7.16 Plasma heat required GJ / t

[0082] Calculation Notes:

[0083] (1) Total heat demand in the furnace: 10.07GJ / t. (Based on 400m 3 HyCROF optimal production data calculation)

[0084] (2) (1295.46 + 35) Nm injected into the furnace 3 / tHeat brought by reducing gas: 7.16GJ / t

[0085] (3) Reaction heat in the reforming furnace (292 kg coal powder + CO2): 2.87 GJ / t;

[0086] Then: to heat the gas injected into the furnace (1295.46 + 35), the heat provided by the plasma = 10.07-7.16+2.87=5.78GJ / t

[0087] S33: Plasma heating gas temperature determination

[0088] Furnace top temperature ℃ 100.00CO gas 100℃ specific heat capacity kJ / Nm3.℃ 1.30CO2 gas temperature after reforming CO ℃ 1825

[0089] Calculation Notes:

[0090] Temperature of high-temperature reducing gas after reforming: ((5.78-2.87)*1000000) / 1295 / 1.30+100=1825℃;

[0091] S34: Determination of the number of plasmas required for injecting reducing agents into the furnace and the power consumption per ton of iron

[0092] Plasma 5MW Number of units 40 Plasma 5MW Power consumption kwh / t2492

[0093] Calculation Notes:

[0094] (1) Calculation based on the heat load of 5MW plasma tons of iron: the number of 5MW plasma = 5.78 / 0.145 = 40;

[0095] (2) Calculation of power consumption of plasma 5MW = 5000 / 80×40 = 2492kwh / t;

[0096] S35: used to supply heat required for chemical raw gas

[0097] The reaction heat consumption of reforming of PCI (154kg / t) is GJ / t1.52. The heat required for externally supplied chemical product gas (595 + 27.5Nm3 / t, 1825℃) is GJ / t1.53. The total heat of the residual top gas from reforming is GJ / t3.05.

[0098] Calculation Notes:

[0099] (1) Reaction heat in the reforming furnace (154 kg coal powder + CO2) = (154.4 * 0.72 / 12 * 166.2) / 1000 = 1.52 GJ / t;

[0100] (2) Externally supplied coal gas temperature (the same as the coal gas temperature in the injection furnace) = 1825.92℃;

[0101] (3) Heating external supply gas (595 + 27.5Nm 3 / t, 1825℃) the required heat = 1.3*684.6*(1825-100) / 1000000=1.53GJ / t;

[0102] Then, the total heat required to heat the externally supplied coal gas = 1.52 + 1.53 = 3.05 GJ / t;

[0103] S36: Number of plasmas required for external supply of chemical raw materials and power consumption per ton of iron

[0104] Plasma 5MW number of 21 Plasma 5MW power consumption kwh / t1317

[0105] Calculation Notes:

[0106] (1) Calculated based on the heat load of 5MW plasma tons of iron: the number of 5MW plasmas = 3.05 / 0.145 = 21;

[0107] (2) Calculation of power consumption of plasma 5MW = 5000 / 80×21 = 1317kwh / t;

[0108] S37: Total amount of plasma and total power consumption per ton of iron of the present invention

[0109] Plasma 5MW number of units 21 Plasma 5MW power consumption kwh / t 1317 Plasma total heat expenditure GJ / t 8.84 Total plasma 5MW number of units 61 Total plasma 5MW power consumption kwh / t

[0110] The total amount of HyCROF plasma and the total power consumption per ton of iron are shown in the table below:

[0111] Calculation Notes:

[0112] (1) Plasma heat expenditure = 3.06 + 5.78 = 8.84 GJ / t;

[0113] (2) Total number of plasma 5MW = 40 + 21 = 61;

[0114] (3) Total plasma 5MW power consumption = 2492 + 1317 = 3809 kwh / t;

[0115] S4: Optimizing HyCROF Plasma Heating Calculations

[0116] The optimization is divided into two parts: 1. Optimization of thermal efficiency in the furnace; 2. Optimization of heat recovery from residual gas:

[0117] S41: Calculation of plasma heating for thermal efficiency optimization in furnaces

[0118] Heat income benchmark optimization GJ / t9.28 Reduction gas temperature after reforming ℃1356.90 Optimized plasma 5MW power consumption kwh / t3288

[0119] Boundary conditions:

[0120] If the thermal efficiency of the HyCROF furnace is improved, the heat required in the furnace will be 9.28GJ / t, and the other boundary parameters remain unchanged. The temperature of the gas entering the furnace after reforming can be greatly reduced, thereby ensuring the long-term safe operation of the refractory materials.

[0121] Calculation Notes:

[0122] (1) Reduction gas temperature after reforming = ((9.28-7.16)*1000000) / 1295 / 1.30+100=1356℃

[0123] (2) After optimization, the power consumption of plasma 5MW is 3288kwh / t;

[0124] S42: Optimization calculation of residual gas heat recovery

[0125] Heat released from 1356℃ to 40℃ (heat recovery) GJ / t1.31 (heat recovery efficiency) %75 Actual heat recovery GJ / t0.98 Total heat of the remaining top gas from reforming (deduction recovery) GJ / t1.66

[0126] Boundary conditions:

[0127] Considering that the coal gas entering the network is 1356℃, it needs to be heated in the smelting process to reduce the coal gas temperature to 40℃ before it can be recovered. The heat recovery efficiency is considered to be 75%. The average heat flux at 1356℃ is 1.45kJ / Nm 3 .℃.

[0128] Calculation Notes:

[0129] (1) The temperature of the inlet gas after reforming the residual top gas drops from 1356°C to 40°C, and the heat released is 684*1.45*4.18*(1356-40) / 1000000=1.31GJ / t;

[0130] (2) Based on the heat recovery efficiency of 75%, the actual heat recovery is 0.98GJ;

[0131] (3) Reshaping 684Nm 3 / t of reducing gas requires 3.05GJ - 0.40GJ (efficiency improvement) - 0.98GJ = 1.66GJ;

[0132] S43: Optimize the final plasma number and power consumption of HyCROF plasma heating

[0133] Total plasma 5MW number of 46 Total plasma 5MW power consumption kwh / t2869

[0134] In summary:

[0135] (1) The present invention is based on oxygen-free smelting. The coke consumption in the solid fuel ratio is carburization, Rd=0.01 direct reduction consumption of coke carbon is 51.86kg / t iron, the CO2 in the top gas is completely reformed and reacted with coal powder, the coal ratio is 446kg / t, and the gas injection rate after reforming is 1330Nm 3 / t, the reducing gas entering the pipe network is 622Nm 3 / t, the gas temperature after CO2 reforming CO is 1825℃.

[0136] (2) According to the first heat balance calculation, the heat income is 10.07GJ. Based on the heat expenditure of pulverized coal reforming and gas heating plasma of 8.84GJ, it is calculated that 5MW plasma requires 61 units and the power consumption is 3809kwh / t.

[0137] (3) If the requirements of refractory materials on gas temperature are taken into account, the heat consumption of the entire furnace can be reduced by 0.79GJ by optimizing the operating parameters. The gas temperature after CO2 reforming to CO can be reduced to 1356℃, and the power consumption of 5MW plasma is 3288kwh / t.

[0138] (4) In addition, considering the gas heat recovery, the final calculation shows that 46 units are needed for a 5MW plasma, and the power consumption is reduced to 2869kwh / t.

[0139] S5: Comparison of the cost and carbon emissions of the present invention with those of conventional blast furnaces

[0140] Specifically, taking the scenario of eliminating decarbonization, oxygen-free smelting, and using green electricity to replace HyCROF gas heating in a 5MW plasma furnace as an example, the carbon emissions of molten iron are compared with those of a traditional blast furnace as follows:

[0141] Calculation boundary: Raw materials adopt uniform price and uniform ore consumption. The residual gas temperature of 1356℃ needs to be reduced to 40℃ in the smelting process. The waste heat is recovered as a deduction and reduction of carbon emissions. The power consumption of green electricity is 4KWh per Nm 3 .

[0142]

[0143] Calculation Notes:

[0144] The cancellation of decarbonization, oxygen-free smelting, and the replacement of HyCROF gas-heated 5MW plasma with green electricity reduce carbon emissions by 92.6% compared to traditional blast furnaces.

[0145] In summary, the above is only used to illustrate the technical solution of the present invention rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in this field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for smelting blast furnace oxygen-free metallurgy using electrified heating and reformed coal gas, characterized in that: The method is implemented through three steps: a basic plan, a transition plan, and a final plan. The equipment composition of the method is as follows: a metallurgical blast furnace, a charging device, a coal gas dust dehydration treatment device, a coal gas CO2 reforming device, a coal gas heat exchange device, a nitrogen source device, a coal injection device, an electric heating device, a coal gas pressurizing device, a composite tuyere device, a furnace body blowing device, and a residual coal gas treatment device, wherein the residual coal gas treatment device includes a power generation device, a boiler, or a gas device, a gas cabinet, a gas storage device, a chemical device, a blast source device, and an oxygen source device. The gas switching function between the three steps of the method is completed by the 13 cutting devices used. 1) The first step is to implement the basic plan: specifically confirm the opening and closing status of the 13 main shut-off devices, adjust the shut-off devices a, e, j, L, and m to the open state, and adjust the shut-off devices b, c, d, f, g, h, i, and k to the closed state; the charge of blast furnace 1 is added into the furnace by the charging device on the furnace top. The charge includes ore and coke. The ore distribution structure adopts alkaline ore, acidic ore and natural lump ore, and the coke ratio is 370-450kg / t. The blast supplied by the blast source device is heated by an electric heating device and then blown into the furnace through the composite tuyere multi-media input hole channel at the bottom of the furnace. The blast temperature is 1200-1300℃ and the blast volume is 1200-1350Nm3 / t. At the same time, the N2 conveying coal injection device of the nitrogen source provides pulverized coal with a coal ratio of 100-150kg / t. The pulverized coal is sprayed into the furnace through the composite tuyere. The oxygen source device provides oxygen with an oxygen content of 85-99% and an oxygen enrichment of 30-50Nm 3 / t, oxygen is injected into the furnace through the composite tuyere at the same time, the high temperature blast burns with the coal powder, coke and oxygen, and an oxidation-reduction reaction occurs in the furnace, generating heat and reducing gas, which takes away the oxygen in the ore and produces qualified molten iron with a [Si] content of 0.35-0.5%, and a by-product slag with a basicity R2=1.05-1.18 times. At the same time, the generated 1500-1650Nm 3 / t of coal gas is dedusted and dehydrated at the furnace top before entering the residual coal gas treatment device. This basic plan is controlled for 5-8 days, at the end of which the coke ratio is 370kg / t and the coal ratio is 150kg / t; 2) The second step is to implement the transition plan: The implementation of this plan must first confirm the open and closed status of the 13 cutting devices in the first basic plan, and switch the operation or keep the state unchanged according to the flow direction of gas heating. The cutting device a is switched from the open state to the closed state; the cutting devices e, j, L, and m continue to be in the open state of the basic plan; the cutting devices c, f, g, h, and i continue to be in the closed state of the basic plan; the cutting devices b, d, and k are switched from the closed state to the open state. The switching operation is carried out under the premise of ensuring intrinsic safety when the blast furnace is in a dormant state; the blast furnace charge ore and coke with a dosage of 50-370kg / t are added to the furnace by the charging device on the furnace top, and the oxygen with an oxygen content of 85-99% is provided by the oxygen source device and sprayed into the furnace using the composite tuyere device according to the oxygen demand of the blast furnace. The oxygen demand of the blast furnace is 0-220Nm 3 / t, and at the same time, the coal powder is provided by the N2 conveying coal injection device of the nitrogen source, and is sprayed into the furnace at a spray rate of 10-150kg / t, and the generated 1379Nm 3 / tThe coal gas is divided into two routes after being dust-cleaned and dehydrated at the furnace top, one route is 400-902Nm 3 / t of top gas is heated by an electric heating device and then enters the CO2 reforming device. At the same time, 129.46-291.94kg / t of pulverized coal is injected into the CO2 reforming device through the N2 coal injection device of the nitrogen source device. The CO2 in the gas reacts with the C in the pulverized coal to generate the reducing agent CO. The reducing agent at this time merges with the original reducing agent in the top gas in the CO2 reforming device and then flows out from the top. The outflowing 574.3-1295.46Nm 3 / t of reducing agent is divided into two parts, one part is 474.3-945Nm 3 / t of reducing agent is sprayed into the furnace through the composite device of the tuyere, and the other part is 100-350Nm 3 / t reducing agent is sprayed into the furnace by the furnace body blowing device; another 477-997Nm 3 / t of residual top gas enters the power generation device of the residual gas treatment device for energy-saving utilization or enters the gas cabinet for storage; the oxygen injected by the composite tuyere device burns with the coal powder and coke to generate heat and reducing gas, and an oxidation-reduction reaction occurs in the furnace to generate reducing gas, which deprives oxygen from the ore and produces qualified molten iron with a [Si] content of 0.4-0.55%, and a by-product slag with a basicity R2=1.05-1.18 times, and at the same time generates 1350-1400Nm 3 / t of coal gas is dedusted and dehydrated at the furnace top before entering the residual coal gas treatment device. This transition plan is controlled for 3-5 days, at the end of which the coke ratio is 50kg / t and the coal ratio is 291.94kg / t; 3) The third step is to implement the final plan: the implementation of this plan requires the operation of the 13 shut-off devices in the transition plan to be switched between open and closed states. The operation is switched or maintained unchanged according to the flow direction of the gas heating, and the shut-off device a remains closed. Cut-off devices b, d, and k are maintained in the open state; cut-off devices e, j, L, and m are switched from the open state to the closed state; cut-off devices c, f, g, h, and i are switched from the closed state of the transition scheme to the open state. The switching operation is preferably performed at the end of the blast furnace transition scheme to implement the production state switching or, considering the inherent safety during the switching, to be performed in the blast furnace in the idle state; The blast furnace charge ore and coke with a minimum of 50kg / t are added into the furnace through the charging device on the furnace top. The oxygen source device is shut off by the m cut-off device until the oxygen content is 0 Nm 3 / t, based on the nitrogen source device providing N2, 446kg / t of pulverized coal is injected into the CO2 reforming device through the coal injection device, 1350-1400Nm 3 / t of top gas enters the CO2 reforming unit, where the CO2 in the gas reacts with the C in the pulverized coal to generate the reducing agent CO. The total amount of the reducing agent and the original reducing agent in the top gas is 1979Nm 3 / t, the two are combined in the CO2 reforming unit and then flow out from the top. The outflowing reducing agent is divided into three parts: the first part is 750-9450Nm 3 / t of reducing gas is sprayed into the furnace through the composite device of the tuyere; the second part is 200-350Nm 3 / t of reducing gas is injected into the furnace by the furnace body injection device; the third part is the surplus 684Nm 3 / t high-temperature reducing agent, after transferring 0.8-1.2GJ of heat to the branch gas on the furnace top through the gas heat exchange device, enters the gas cabinet of the residual gas treatment device or the chemical device for energy-saving storage or chemical carbon fixation utilization, realizing zero-carbon metallurgy with full utilization of CO2; the parameter control of the final solution is: the blast furnace condition is stable and smooth, and qualified molten iron with a [Si] content of 0.35-0.45% is generated, and at the same time, a by-product slag with alkalinity controlled at R2=1.05-1.15 times is generated, there is no hanging material, and the actual hourly material rate is equal to the theoretical material rate.

2. The method for smelting blast furnace oxygen-free metallurgy using electrified heating and reformed coal gas according to claim 1, characterized in that: The branched gas refers to the gas that is divided into two branches before the top gas enters the CO2 reforming device. One branch directly enters the CO2 reforming device, and the other branch is mixed with the remaining high-temperature gas after passing through the gas heat exchange device and the CO2 reforming device, and then mixed and returned through the gas pressurizing device, and then enters the first branch of the top gas that directly enters the CO2 reforming device.

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