Carbon-cycle based blast furnace and converter steel production method

Abstract

The present invention relates to the field of iron and steel smelting, and in particular to a blast furnace / converter steel production method based on carbon circulation. The method includes the steps of: making iron in a blast furnace to obtain molten iron; introducing the molten iron into a converter to make steel in the converter to obtain molten steel and untreated converter gas; pressurizing, deoxidizing, dehydrating and decarbonizing the untreated converter gas to obtain analyzed gas and treated converter gas; and circulating the treated converter gas to the blast furnace for blowing back, thereby adjusting the proportion of reducing gas in the bosh gas in the blast furnace. The method realizes the circulating use of converter gas, and after decarbonizing the converter gas, circulates it to the blast furnace for blowing back, improving the content of reducing gas in the bosh gas in the blast furnace, promoting indirect reduction in the blast furnace, and reducing direct reduction, thereby reducing the consumption of carbonaceous fuel in the blast furnace steelmaking process, and effectively reducing CO2 emissions.

Description

[Technical Field]

[0001] The present invention relates to the field of iron and steel smelting, and in particular to a blast furnace / converter steel production method based on carbon circulation. [Background technology]

[0002] Promoting greening and low-carbonization is a major theme in the development of the global steel industry today. The steelmaking process is the main carbon-emitting process in the steel industry (accounting for 85% of the entire steelmaking process), and blast furnaces and converters will continue to be used around the world for a long time to come. Therefore, achieving breakthroughs in greening and low-carbon smelting technology is extremely important for supporting the low-carbon development of the steel industry and achieving the carbon peak and carbon neutral goals.

[0003] In particular, steel manufacturing is an energy- and resource-intensive industry, generating large amounts of secondary energy and by-products, and the current recycling rate of these secondary resources is low. Improving the efficiency of secondary energy use in the steel manufacturing process is highly necessary and has great potential for development in terms of reducing energy consumption and carbon dioxide emissions. Currently, the amount of converter gas produced is 80 to 120 m per ton of steel. 3 However, the main method of using converter gas in steelworks is still to burn it for heat supply, which results in low gas utilization rate and direct combustion generating large amounts of carbon dioxide, which does not meet the demands for green and low-carbon development. Summary of the Invention [Problem to be solved by the invention]

[0004] In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a blast furnace / converter steel production method based on carbon circulation to solve the problem of high carbon dioxide emissions in the prior art steel production process. [Means for solving the problem]

[0005] To achieve the above and other objects, the present invention provides a method for manufacturing a semiconductor device comprising: The process of producing molten iron by smelting iron in a blast furnace, introducing the molten iron into a converter and performing steelmaking in the converter to obtain molten steel and untreated converter gas; pressurizing, deoxidizing, dehydrating and decarbonizing the untreated converter gas to obtain an analysis gas and a treated converter gas; and a step of circulating the treated converter gas back into the blast furnace to adjust the proportion of reducing gas in the bosh gas in the blast furnace.

[0006] Preferably, the step of subjecting the untreated converter gas to pressurization, deoxidation, dehydration and decarbonization to obtain the analysis gas and the treated converter gas comprises: pressurizing the untreated converter gas to 0.50 MPa to 0.65 MPa by a gas pressurizing device to obtain pressurized converter gas; deoxidizing the pressurized converter furnace gas by a gas deoxidizer until the oxygen content is less than 1 ppm to obtain a deoxidized converter furnace gas; dehydrating the deoxidized converter gas by a gas dehydration device until the dehydration efficiency is greater than 95% to obtain a dehydrated converter gas; and decarbonizing the dehydrated converter furnace gas by a gas decarbonization device until a CO2 desorption rate reaches 95% or more, thereby obtaining a decarbonized converter furnace gas.

[0007] Preferably, the CO content in the raw converter gas is 40% or more.

[0008] Preferably, the step of pressurizing, deoxidizing, dehydrating and decarbonizing the raw converter gas to obtain a treated converter gas further comprises the step of desulfurizing and denitrifying the raw converter gas, wherein the desulfurizing precedes the denitrifying.

[0009] Preferably, the step of desulfurizing and denitrifying the untreated converter gas comprises: desulfurizing the pressurized converter furnace gas by a desulfurization device until the sulfur content is less than 10 ppm to obtain desulfurized converter furnace gas; and a step of denitrifying the converter furnace gas decarbonized by the denitrification device until the denitrification efficiency is 90% or more, thereby obtaining denitrified converter furnace gas.

[0010] Preferably, before the desulfurization treatment, the temperature of the pressurized converter gas is controlled to 60°C to 90°C by a cooling device.

[0011] Preferably, the pressurization, desulfurization, deoxidation, dehydration, decarbonization and denitrification treatments are carried out in this order.

[0012] Preferably, the step of adjusting the proportion of reducing gas in the bosh gas in the blast furnace by circulating and blowing back the treated converter gas into the blast furnace comprises: heating the treated converter gas to 850℃-950℃ by a gas heating device to obtain heated converter gas; The heated converter gas is circulated and blown back into the blast furnace by a gas blowing device, in which the blowing port of the gas blowing device is aligned with the furnace body and / or tuyere of the blast furnace, and the converter gas is blown into the furnace body and / or tuyere of the blast furnace.

[0013] Preferably, the heat required for heating the gas heating device is provided by combustion of gas in a gas pipeline, where the gas in the gas pipeline includes blast furnace gas and / or analytical gas from the blast furnace.

[0014] Preferably, the decarbonization process is a dry decarbonization process or a wet decarbonization process, and if the decarbonization process is a dry decarbonization process, the CO2 concentration in the analyzed gas is 95% or less, and the analyzed gas is combined with a gas pipeline network connected to the blast furnace, and if the decarbonization process is a wet decarbonization process, the CO2 concentration in the analyzed gas is greater than 95%, and the analyzed gas is subjected to CCUS treatment. [Effects of the Invention]

[0015] The blast furnace and converter steel production method based on carbon circulation of the present invention at least realizes the cyclical use of converter gas, and after decarbonizing the converter gas, circulates it to the blast furnace and blows it back, thereby improving the reducing gas content in the bosh gas in the blast furnace, promoting indirect reduction in the blast furnace, and reducing direct reduction, thereby reducing the consumption of carbonaceous fuel in the blast furnace steelmaking process and effectively reducing CO2 emissions. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a flowchart of Example 1 of a blast furnace-converter steel production method based on carbon circulation provided by the present application. [Figure 2] 1 is a schematic diagram of a production system used to implement Example 1. FIG. [Figure 3] 1 is a flowchart of Example 2 of a blast furnace-converter steel production method based on carbon circulation provided by the present application. [Figure 4] FIG. 10 is a schematic diagram of a production system used in carrying out Example 2. [Figure 5] 1 is a flowchart of Example 3 of a blast furnace-converter steel production method based on carbon circulation provided by the present application. [Figure 6] FIG. 10 is a schematic diagram of a production system used in carrying out Example 3. [Figure 7] 1 is a flowchart of Example 4 of a blast furnace-converter steel production method based on carbon circulation provided by the present application. [Figure 8] FIG. 10 is a schematic diagram of a production system used in carrying out Example 4. [Figure 9] 1 is a flowchart of Example 5 of a blast furnace-converter steel production method based on carbon circulation provided by the present application. [Figure 10] FIG. 10 is a schematic diagram of a production system used in carrying out Example 5. [Figure 11] FIG. 2 is a schematic diagram showing a structure for blowing gas onto a blast furnace body using a gas blowing device. [Figure 12] FIG. 2 is a schematic diagram showing a structure for blowing gas onto a blast furnace body and tuyere using a gas blowing device. DETAILED DESCRIPTION OF THE INVENTION

[0017] The following description of the present invention will be given in conjunction with specific examples, and other advantages and effects of the present invention will be readily apparent to those skilled in the art from the disclosure herein. The present invention can also be implemented or applied in accordance with other specific examples, and the details of the present specification can be modified or changed in various ways based on different perspectives and applications without departing from the spirit of the present invention.

[0018] Please refer to Figures 1 to 6. The figures shown in the present embodiment merely illustrate the basic concepts of the present invention and are not based on the number, shape, and dimensions of the components actually implemented. They only show the components relevant to the present invention. The shape, number, and proportion of the components actually implemented may be arbitrarily changed, and the layout of the components may be more complex. The structures, proportions, sizes, etc. shown in the drawings attached to this specification are merely intended to facilitate the understanding and reading of those skilled in the art in accordance with the contents disclosed in the specification. They are not intended to limit the limitations on the conditions under which the present invention can be implemented. Therefore, they have no substantial technical meaning. Any structural modifications, changes in proportional relationships, or adjustments in size should remain within the scope of the technical content disclosed by the present invention, as long as they do not affect the effects and objectives that can be achieved by the present invention. Furthermore, terms such as "upper," "lower," "left," "right," "center," and "first" used in this specification are merely used for convenience of explanation and do not limit the scope of the present invention. Any changes or adjustments to their relative relationships are considered to be within the scope of the present invention without substantially changing the technical content.

[0019] Before describing the embodiments of the present invention in detail, the application environment of the present invention will be described. The technology of the present invention is mainly applied to steel smelting, and in particular to carbon circulation in the blast furnace and converter steelmaking process. The present invention is used to solve the problem of high carbon dioxide emissions in the conventional steelmaking process.

[0020] Referring to FIGS. 1-10, in some embodiments, the present application provides: smelting iron in a blast furnace 1 to obtain molten iron; introducing molten iron into a converter 2 and producing steel in the converter 2 to obtain molten steel and untreated converter gas; pressurizing, deoxidizing, dehydrating and decarbonizing the raw converter gas to obtain an analysis gas and a treated converter gas; and circulating the treated converter gas back into the blast furnace (1) and adjusting the proportion of reducing gas in the bosh gas in the blast furnace (1).

[0021] Furthermore, the mixture is subjected to pressure, deoxidation, dehydration and decarbonization treatments in this order.

[0022] Preferably, the blast furnace 1 is connected to a converter 2, and converter gas generated by the converter 2 during the steelmaking process is collected and stored by a converter gas collection device 4.

[0023] Furthermore, the converter gas collection device 4 can be a converter gas cabinet or a converter gas user pipe network.

[0024] The carbon cycle-based blast furnace and converter steel production method can utilize converter gas generated during the steelmaking process in a simple process. After pressurizing, deoxidizing, dehydrating and decarbonizing the converter gas, it is circulated into the blast furnace for blowback ironmaking, making full use of the effective reducing gas in the converter gas, improving the proportion of reducing gas in the blast furnace bosh gas, and promoting indirect reduction in the blast furnace. This reduces the consumption of coal and carbonaceous fuel in blast furnace ironmaking and effectively reduces CO2 emissions from the blast furnace and converter steel production system.

[0025] Referring to FIGS. 1-10, in some embodiments, pressurizing, deoxidizing, dehydrating, and decarbonizing raw converter gas to obtain analyzed gas and treated converter gas includes: a step of pressurizing the untreated converter gas to 0.50 MPa to 0.65 MPa by a gas pressurizing device 51 to obtain pressurized converter gas; deoxidizing the pressurized converter gas by a gas deoxidizer 53 until the oxygen content is less than 1 ppm to obtain a deoxidized converter gas; dehydrating the deoxidized converter gas by a gas dehydration device 54 until the dehydration efficiency is greater than 95% to obtain a dehydrated converter gas; and a step of decarbonizing the dehydrated converter furnace gas by a gas decarbonization device 55 until a CO2 removal rate reaches 95% or more, thereby obtaining a decarbonized converter furnace gas.

[0026] Preferably, the gas pressurizing device 51, the gas deoxygenating device 53, the gas dehydrating device 54 and the gas decarbonizing device 55 are connected in series.

[0027] Furthermore, the gas pressurizing device 51 is connected to the converter gas collecting device 4 .

[0028] 1, 2, and 7 to 10, in some embodiments, the CO content in the untreated converter furnace gas is 40% or more, that is, the carbon monoxide content in the converter furnace gas discharged to the gas pressurizing device 51 by the converter furnace gas collecting device 4 is 40% or more. Here, when the CO content of the untreated converter furnace gas is 40% or more, the untreated converter furnace gas can be subjected to pressurization, deoxidation, dehydration, and decarbonization treatments in this order to obtain a treated converter furnace gas.

[0029] Referring to Figures 3-6, in some embodiments, pressurizing, deoxidizing, dehydrating, and decarbonizing the raw converter gas to obtain a treated converter gas further includes subjecting the raw converter gas to a desulfurization and denitrification process, wherein the desulfurization process precedes the denitrification process.

[0030] Preferably, the converter gas is pressurized, desulfurized, deoxidized, dehydrated, decarbonized, and denitrified in this order.

[0031] Preferably, the desulfurization and denitrification of the raw converter gas comprises: The process includes a step of desulfurizing the pressurized converter furnace gas by the desulfurization device 52 until the sulfur content is less than 10 ppm to obtain the desulfurized converter furnace gas, and the sulfur content in the desulfurized converter furnace gas is 0.1 ppm to 10 ppm.

[0032] The decarbonized converter gas is denitrified by the denitrification device 56 until the denitrification efficiency reaches 90% or more, thereby obtaining a denitrified converter gas.

[0033] Furthermore, a gas pressurizing device 51, a gas desulfurization device 52, a gas deoxygenation device 53, a gas dehydration device 54, a gas decarbonization device 55, and a gas denitrification device are connected in this order.

[0034] Preferably, before desulfurization, the temperature of the pressurized converter gas is controlled to 60°C to 90°C by a cooling device. The cooling device can be installed in the gas pressurizing device 51, and the cooling capacity at the outlet end of the gas pressurizing device 51 can be adjusted by the cooling device.

[0035] Referring to FIGS. 3-6, in some embodiments, untreated converter gas can be sequentially subjected to pressurization, desulfurization, deoxidation, dehydration, decarbonization, and denitrification processes to obtain treated converter gas.

[0036] Referring to FIGS. 1 to 12, in some embodiments, the treated converter gas is circulated and blown back into the blast furnace 1 to adjust the proportion of reducing gas in the bosh gas in the blast furnace 1. a step of heating the treated converter gas to 850°C to 950°C by a gas heating device 6 to obtain a heated converter gas; The heated converter gas is circulated and blown back into the blast furnace 1 by the gas blowing device 3, during which the blowing port of the gas blowing device 3 is aligned with the furnace body 11 and / or tuyere 12 of the blast furnace 1, and the converter gas is blown into the furnace body 11 and / or tuyere 12 of the blast furnace 1.

[0037] Here, the gas heating device 6 can be installed or not depending on the need, and the gas heating device 6 can be used to blow converter gas back into the blast furnace 1 to replenish the heat.

[0038] Preferably, if a gas heating device 6 is provided, the heat required for heating the gas heating device 6 is supplied by combustion of gas in the gas pipeline 7, the gas in the gas pipeline 7 including blast furnace gas in the blast furnace 1 and / or analysis gas.

[0039] Furthermore, the gas pipe network 7 is connected to the blast furnace 1 and the gas heating device 6, collects the blast furnace gas in the blast furnace 1, and supplies heat to the gas heating device 6 by combustion.

[0040] Preferably, if no denitrification treatment is performed, the gas network 7 is connected to a gas decarbonization unit in order to recover the analyzed gases in the treated converter gas.

[0041] Preferably, when denitrification treatment is carried out, a gas network 7 is connected to the carbonitriding / decarbonization unit in order to recover the analyzed gas in the treated converter gas.

[0042] 1 to 10, in some embodiments, the decarbonization process may be either dry decarbonization or wet decarbonization. When the decarbonization process is dry decarbonization, the CO2 concentration in the analyzed gas is 95% or less, and the analyzed gas is introduced into a gas pipeline 7 connected to the blast furnace 1. When the decarbonization process is wet decarbonization, the CO2 concentration in the analyzed gas is 95% or more, and the analyzed gas is subjected to CCUS.

[0043] Furthermore, when the analyzed gas is subjected to CCUS (Carbon Capture, Utilization and Storage) processing, the gas may be processed in a CCUS device connected to the decarbonization device 55.

[0044] Below, one unit of 2850m 3Taking a blast furnace as an example, a simulation calculation is carried out on the physical and thermal equilibrium of the blast furnace, and the present invention will be further explained in conjunction with different embodiments.

[0045] Tables 1 to 4 show the blast furnace raw fuel conditions and conventional blast furnace ironmaking process parameters, respectively.

[0046] [Table 1]

[0047] [Table 2]

[0048] [Table 3]

[0049] [Table 4]

[0050] Example 1 In this example, decarbonization is performed using a converter gas dry process, without denitrification or heating. Referring to Figures 1 and 2, the blast furnace-converter steel production system based on carbon circulation in this example includes, but is not limited to, a converter gas collection device 4, a gas pressurization device 51, a gas deoxidizer 53, a gas dehydrator 54, a gas decarbonizer 55, a gas blowing device 3, a blast furnace 1, a gas pipeline 7, and a converter 2. The blast furnace 1, the gas pipeline 7, and the converter 2 are the same as those in a conventional blast furnace-converter system, and the raw fuel conditions for the conventional blast furnace are described in detail below in Tables 1 to 3.

[0051] High-temperature molten iron produced in the blast furnace 1 is transported to the converter 2, where it undergoes decarbonization, dephosphorization, desulfurization, deoxidation, and other processes to obtain acceptable molten steel 9. The converter 2 is a cyclical steelmaking device, with a typical smelting cycle of 25 to 45 minutes, and requires oxygen blowing for decarbonization. Therefore, converter gases with different CO contents are generated intermittently during the steelmaking process, and when the CO content of the converter gas reaches 40% or more, it is introduced into the converter gas collection device 4, stored, and used in downstream processes.

[0052] In this embodiment, the converter gas collecting device 4 may be a converter gas cabinet. The converter gas cabinet collects approximately 77,000 Nm3 of converter gas with a CO content of 40% or more. 3 / h, and the specific converter gas components are shown in Table 3, of which CO: 44.2%, CO2: 27.7%, H2: 1.5%, and N2: 28.6%. The extracted converter gas is pressurized to 0.50 MPa to 0.65 MPa by gas pressurization device 51, allowing the subsequent gas decarbonization device 55 to perform decarbonization treatment and the gas injection device 3 to normally inject the converter gas into the blast furnace 1.

[0053] As shown in Table 3, converter gas also contains a certain proportion of oxygen, with a normal range of 0-0.4%. Considering that the molecular sieve in the gas decarbonization unit 55 is afraid of oxygen and that converter gas has a risk of gas explosion during the compression and heating process, the gas deoxidization unit 53 is used to deoxidize the converter gas, and the treated oxygen content is less than 1 ppm.

[0054] The oxygen-removed converter gas is dehydrated by the gas dehydration device 54, and then introduced into the gas decarbonization device 55 to decarbonize the converter gas. The decarbonization process can be a dry decarbonization process, and the amount of decarbonized converter gas is about 52,000 Nm 3 / h, and the amount of analyzed gas generated was approximately 25,000 Nm 3 / h, and the decarbonized gas and analyzed gas components are shown in Table 5.

[0055] [Table 5]

[0056] After the gas decarbonization device 55 adopts the dry decarbonization process, the generated analyzed gas still contains about 14% CO, which cannot be directly emitted or subjected to CCUS (Carbon Capture, Utilization and Storage) treatment, and the generated analyzed gas is directly routed via a pipeline to the gas network 7 and used as fuel.

[0057] The pressurized and decarbonized converter gas is directly cooled and then injected into the blast furnace 1 through the blast furnace tuyeres via the gas injection device 3, which significantly improves the proportion of reducing gas in the bosh gas in the blast furnace 1. The bosh gas composition is as shown in Table 6, which promotes indirect reduction in the blast furnace and reduces direct reduction, thereby reducing fuel consumption per ton of iron smelted in the blast furnace 1 and lowering CO2 emissions in the blast furnace smelting process.

[0058] [Table 6]

[0059] According to the calculations of the heat balance and material balance of the blast furnace, after the decarbonized converter gas is blown back into blast furnace 1, the fuel rate is 463 kg / t, of which the coal rate is 150 kg / t and the coke rate is 313 kg / t. Compared with the conventional blast furnace, the carbon content of fuel has been significantly reduced, with the fuel rate reduced by 52 kg / t, the direct carbon reduction ratio is 10%, and CO2 emissions per ton of iron have been reduced by approximately 165 kg / t. The specific indicators are shown in Table 7.

[0060] [Table 7]

[0061] The molten iron produced in the blast furnace 1 is made into steel in the converter 2, and the resulting molten steel is used in subsequent processes, while the converter gas, a by-product, is recycled via converter gas collection device 4. By recycling the converter gas in this way, the objectives of highly efficient smelting in the blast furnace and reducing CO2 emissions can be achieved.

[0062] Example 2 In this example, decarbonization, denitrification, and heating were performed using a converter gas dry method. Referring to Figures 3 and 4, the blast furnace-converter steel production system based on carbon circulation in this example includes, but is not limited to, a converter gas collection device 4, a gas pressurization device 51, a gas desulfurization device 52, a gas deoxidation device 53, a gas dehydration device 54, a gas decarbonization device 55, a gas denitrification device 56, a gas heating device 6, a gas blowing device 3, a blast furnace 1, a gas pipeline network 7, and a converter 2. Among these, the blast furnace 1, the gas pipeline network 7, and the converter 2 are the same as those in a conventional blast furnace-converter system.

[0063] In this embodiment, the converter gas collection device 4 may be a converter gas cabinet, but this embodiment differs from embodiment 1 in that cooling devices are installed in the gas desulfurization device 52, gas denitrification device 56, gas heating device 6, and gas pressurization device 51. Since the other systems, processing methods, and raw fuel conditions are the same as those in embodiment 1, only the differences will be described without repeating them.

[0064] In this embodiment, the cooling capacity of the outlet end of the gas pressurization device 51 is adjusted by a cooling device so that the outlet temperature of the pressurized converter gas is in the range of 60°C to 90°C to meet the desulfurization needs of the converter gas. Typical converter gas contains 15% to 30% nitrogen. To increase the proportion of reducing gas flowing into the blast furnace 1 and enhance the decarbonization effect, this embodiment performs denitrification treatment using a gas denitrification device 56, thereby reducing the N2 content of the input furnace. Because converter gas contains 20 to 30 ppm of sulfur, when denitrification is performed by the gas denitrification device 56, there are extremely high requirements for controlling the sulfur content to prevent poisoning of the denitrification adsorbent. Therefore, to meet the gas denitrification requirements, desulfurization treatment must be performed using a gas desulfurization device 52. The converter gas temperature is controlled to 60°C to 90°C, and the post-treatment sulfur content must be less than 10 ppm, for example, the S content can be in the range of 0.1 ppm to 10 ppm.

[0065] In this example, the converter furnace gas was heated and processed in the following order: pressurization, desulfurization, deoxidation, dehydration, decarbonization, and denitrification. The decarbonization of the converter furnace gas was performed using a dry decarbonization process, and the converter furnace gas was then denitrified after decarbonization. The volume of the converter furnace gas after decarbonization and denitrification was approximately 35,000 Nm 3 / h, the amount of analyzed gas generated was approximately 42,000 Nm 3 / h and gas composition are shown in Table 8.

[0066] [Table 8]

[0067] Even after adopting the dry decarbonization process, the generated analyzed gas still contains approximately 8% CO, which cannot be directly discharged or subjected to CCUS treatment. Instead, the generated analyzed gas is directly routed via pipeline to the blast furnace gas pipeline network 7 and used as fuel.

[0068] The decarbonized and denitrified converter gas is heated to 850-950°C by gas heating device 6, and the converter gas is blown into blast furnace 1 to replenish the heat, and the heat required by gas heating device 6 is provided by burning blast furnace gas in gas pipe network 7.

[0069] The pressurized, decarbonized, denitrified, and heated converter gas is then injected into the blast furnace 1 through the blast furnace tuyeres via a gas injection device 3, significantly improving the proportion of reducing gas in the bosh gas in the blast furnace 1. The bosh gas composition is as shown in Table 9, which promotes indirect reduction in the blast furnace and reduces direct reduction, thereby reducing fuel consumption per ton of iron smelted in the blast furnace and lowering CO2 emissions during the blast furnace smelting process.

[0070] [Table 9]

[0071] According to the calculations of the heat and material balance of the blast furnace, after the decarbonized, denitrified, and heated converter gas is blown back into blast furnace 1, the fuel rate is 433 kg / t, of which the coal rate is 180 kg / t and the coke rate is 253 kg / t. Compared with the conventional blast furnace, the carbon content of fuel has been significantly reduced, with the fuel rate reduced by 82 kg / t, the direct carbon reduction ratio is 16%, and CO2 emissions per ton of iron have been reduced by approximately 256 kg / t. The specific indicators are shown in Table 10.

[0072] [Table 10]

[0073] Example 3 In this example, decarbonization, denitrification, and heating are performed using a converter gas dry process. Referring to Figures 5 and 6, the blast furnace / converter steel production system based on carbon circulation in this example includes, but is not limited to, a converter gas collection device 4, a gas pressurization device 51, a gas desulfurization device 52, a gas deoxidation device 53, a gas dehydration device 54, a gas decarbonization device 55, a gas denitrification device 56, a gas blowing device 3, a blast furnace 1, a gas pipeline 7, and a converter 2. The blast furnace 1, the gas pipeline 7, and the converter 2 are the same as in a conventional blast furnace / converter system. This example differs from Example 2 in that the decarbonized and denitrified converter gas is not heated but is instead blown directly into the blast furnace 1 using cold gas. The other systems, processing methods, and raw fuel conditions are identical to those in Example 2, so a detailed description will be omitted and only the differences will be discussed.

[0074] The pressurized, decarbonized, and denitrified converter gas is then injected into the blast furnace 1 through the blast furnace tuyeres via a gas injection device 3, significantly improving the proportion of reducing gas in the bosh gas in the blast furnace 1. The bosh gas composition is as shown in Table 11, which promotes indirect reduction in the blast furnace and reduces direct reduction, thereby reducing fuel consumption per ton of iron smelted in the blast furnace and lowering CO2 emissions during the blast furnace smelting process.

[0075] [Table 11]

[0076] According to the calculations of the heat and material balance of the blast furnace, after the decarbonized, denitrified and heated converter gas is blown back into blast furnace 1, the fuel rate is 447 kg / t, of which the coal rate is 150 kg / t and the coke rate is 297 kg / t. Compared with the conventional blast furnace, the carbon content of fuel is significantly reduced, with the fuel rate reduced by 68 kg / t, the direct carbon reduction ratio is 13%, and the CO2 emissions per ton of iron is reduced by approximately 213 kg / t.

[0077] Example 4 In this example, decarbonization was performed using a converter gas dry process, without denitrification, and heating was performed. Referring to Figures 7 and 8, the blast furnace-converter steel production system based on carbon circulation in this example includes, but is not limited to, a converter gas collection device 4, a gas pressurization device 51, a gas deoxidation device 53, a gas dehydration device 54, a gas decarbonization device 55, a gas heating device 6, a gas injection device 3, a blast furnace 1, a gas pipe network 7, and a converter 2. The blast furnace 1, the gas pipe network 7, and the converter 2 are the same as in a conventional blast furnace-converter system. This example differs from Example 2 in that gas desulfurization and gas denitrification processes are not performed, and the decarbonized converter gas is heated in the gas heating device 6 and then injected into the blast furnace 1 by the gas injection device 3. The other system and processing methods, as well as the raw fuel conditions, are completely identical to those in Example 2, and therefore, only the differences will be described without repeating them.

[0078] The converter gas is not denitrified, so the gas desulfurization unit is removed. The converter gas is pressurized, deoxidized, and dehydrated, and then enters the gas decarbonization unit 55 for gas decarbonization. The dry decarbonization process is still used, and the volume of the converter gas after decarbonization is about 52,000 Nm 3 / h, and the amount of analyzed gas generated was approximately 25,000 Nm 3 / h, and the gas composition after decarbonization and the analyzed gas are shown in Table 12.

[0079] [Table 12]

[0080] After the gas decarbonization device 55 adopts the dry decarbonization process, the generated analyzed gas still contains about 14% CO, which cannot be directly discharged or CCUS treated, and the generated analyzed gas is directly routed via a pipeline to the blast furnace gas pipeline network 7 and used as fuel.

[0081] The pressurized and decarbonized converter gas is directly injected in a cold state into the blast furnace 1 through the blast furnace tuyeres via the gas injection device 3, which significantly improves the proportion of reducing gas in the bosh gas in the blast furnace 1. The bosh gas composition is as shown in Table 13, which promotes indirect reduction in the blast furnace and reduces direct reduction, thereby reducing the fuel consumption per ton of iron smelted in the blast furnace and lowering the CO2 emissions during the blast furnace smelting process.

[0082] [Table 13]

[0083] According to the calculation of the heat balance and material balance of the blast furnace, after the decarbonized, denitrified and heated converter gas is blown back into blast furnace 1, the fuel rate is 449 kg / t, of which the coal rate is 160 kg / t and the coke rate is 289 kg / t. Compared with the conventional blast furnace, the carbon content of fuel is significantly reduced, with the fuel rate reduced by 66 kg / t, the direct carbon reduction ratio is 12.8%, and the CO2 emissions per ton of iron is reduced by about 206 kg / t. See Table 14 for details.

[0084] [Table 14]

[0085] Example 5 In this example, decarbonization was performed using a wet converter gas process, and heating was performed without denitrification. Referring to Figures 9 and 10, the blast furnace-converter steel production system based on carbon circulation in this example includes, but is not limited to, a converter gas collection device 4, a gas pressurization device 51, a gas dehydration device 54, a gas decarbonization device 55, a CCUS device 8, a gas heating device 6, a gas blowing device 3, a blast furnace 1, a gas pipeline network 7, and a converter 2. Among these, the blast furnace 1, the gas pipeline network 7, and the converter 2 are the same as those in a conventional blast furnace-converter system. The converter gas is not subjected to gas desulfurization or denitrification treatment, and a wet process is used for gas decarbonization. The purity of the CO2 in the analyzed gas is relatively high, and it can be directly connected to the CCUS device 8 or directly discharged, without being merged into the gas pipeline network 7. The decarbonized gas is heated by the gas heating device 6 and then injected into the blast furnace 1 by the gas injection device 3, which is different from Example 2. The other systems and processing methods, as well as the raw fuel conditions, are completely consistent with Example 2, so only the differences will be described without repeating them.

[0086] This example differs from Example 4 in that the gas decarbonization equipment is different. This example uses a wet decarbonization process, while Example 3 uses a dry decarbonization process. Since the difference in decarbonization effect is not significant, there are no significant fundamental changes to the reaction in the blast furnace and the decarbonization effect, and this will not be repeated further.

[0087] The converter gas is not denitrified, so the gas desulfurization equipment is removed. The converter gas is pressurized, deoxidized, and dehydrated, and then enters the gas decarbonization equipment 55 for gas decarbonization. A wet decarbonization process is used, and the volume of the converter gas after decarbonization is about 56,000 Nm 3 / h, the amount of analyzed gas generated was approximately 21,000 Nm 3 / h, decarbonized gas and analyzed gas composition are shown in Table 15.

[0088] [Table 15]

[0089] The gas decarbonization device 55 uses a wet decarbonization process, and the CO2 concentration in the generated analyzed gas is very high, reaching over 99%, and is basically CO-free, so it can be directly subjected to CCUS treatment or directly discharged without being re-entered into the gas pipeline 7.

[0090] Example 6 Referring to Fig. 11, the decarbonized converter gas in each of the above-mentioned Examples 1 to 5 is injected into the blast furnace 1 through the tuyere 12. At the same time, depending on different operating mode conditions and actual carbon reduction demands, the decarbonized converter gas can be injected from the furnace body 11 of the blast furnace 1. The other system processing methods are the same as those in Examples 1 to 5, and will not be described again.

[0091] Example 7 Referring to Fig. 12, the decarbonized converter gas in each of the above-mentioned Examples 1 to 5 is injected into the blast furnace 1 through the tuyere 12. At the same time, depending on different operating mode conditions and actual carbon reduction demands, the decarbonized converter gas can be simultaneously injected from the furnace body 11 and the tuyere 12 of the blast furnace 1. The other system processing methods are the same as those in Examples 1 to 5, and will not be described again.

[0092] The carbon-recycling-based blast furnace and converter steel production method of the present invention has simple processes and is easy to operate. By adopting a carbon-recycling blast furnace and converter steel production system, converter gas is pressurized, desulfurized, deoxidized, dehydrated, decarbonized, and denitrified. Converter gas generated during steelmaking is pressurized, desulfurized, deoxidized, dehydrated, decarbonized, denitrified, and heated before being circulated and injected into the blast furnace, making full use of the converter gas's effective reducing gas content, improving the reducing gas ratio of blast furnace bosh gas, promoting blast furnace indirect reduction, and reducing the consumption of carbonaceous fuel in blast furnace steelmaking. This improves the utilization efficiency of converter gas and effectively reduces CO2 emissions in the blast furnace and converter steelmaking process, further saving energy and protecting the environment.

[0093] The above-described embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Those skilled in the art may modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed by the present invention should be encompassed by the scope of the appended claims. [Explanation of symbols]

[0094] 1 blast furnace 11 Furnace body 12 Tuyere 2 Converter 3 Gas spraying device 4 Converter gas collection device 51 Gas pressure device 52 Gas desulfurization equipment 53 Gas deoxidizer 54 Gas dehydration equipment 55 Gas decarbonization equipment 56 Gas denitrification equipment 6 Gas heating equipment 7 Gas Pipeline 8 CCUS equipment 9 Molten Steel

Claims

1. The process of obtaining molten iron by producing iron in a blast furnace, A process of introducing the molten iron into a converter and producing steel in the converter to obtain molten steel and untreated converter gas. and, The untreated converter gas is pressurized, deoxidized, dehydrated, and decarbonized to produce analytical gas and The process of obtaining the treated converter gas comprises: The untreated converter gas is pressurized to 0.50 MPa to 0.65 MPa using a gas pressure device. obtaining pressurized converter gas; The pressurized converter gas is deoxidized by a gas deoxidizer until the oxygen content is reduced to less than 1 ppm. to obtain deoxidized converter gas; The deoxidized converter gas is dehydrated by a gas dehydration device until the dehydration efficiency is greater than 95%. and obtaining dehydrated converter gas. The dehydrated converter gas is desorbed by a gas decarbonization device until the CO 2 desorption rate reaches 95% or more. obtaining carbonized and decarbonized converter gas; The treated converter gas is circulated and blown back into the blast furnace, thereby reducing the amount of boiler gas in the blast furnace. and adjusting the proportion of reducing gas in the gas. A blast furnace / converter steel production method based on carbon circulation, characterized by:

2. 2. The method according to claim 1, wherein the CO content in the untreated converter gas is 40% or more. A blast furnace and converter steel production method based on the carbon cycle.

3. The untreated converter gas is pressurized, deoxidized, dehydrated and decarbonized to produce a treated converter gas. The step of obtaining the converter gas comprises subjecting the untreated converter gas to desulfurization and denitrification. further comprising wherein the desulfurization treatment precedes the denitrification treatment; 2. The method for producing steel using a blast furnace and converter based on carbon circulation according to claim 1.

4. The step of desulfurizing and denitrifying the untreated converter gas comprises: The pressurized converter gas is desulfurized by the desulfurization device until the sulfur content is less than 10 ppm. obtaining a desulfurized converter gas; The decarbonized converter gas is denitrified by the denitrification device until the denitrification efficiency reaches 90% or more. obtaining a nitrogenated converter gas; 4. The method for producing steel using a blast furnace and converter based on carbon circulation according to claim 3.

5. Before the desulfurization treatment, the temperature of the pressurized converter gas is controlled to 60 to 90°C by a cooling device. do, 4. The method for producing steel using a blast furnace and converter based on carbon circulation according to claim 3.

6. The pressurization, desulfurization, deoxidation, dehydration, decarbonization, and denitrification treatments are carried out sequentially.

4. The method for producing steel using a blast furnace and converter based on carbon circulation according to claim 3.

7. The treated converter gas is circulated and blown back into the blast furnace, and the resulting bosh gas is then The step of adjusting the proportion of the reducing gas in The converter gas treated by the gas heating device is heated to 850 to 950°C. a process for obtaining the converted converter gas; The heated converter gas is circulated and blown back into the blast furnace by a gas blowing device, The gas blowing device has an inlet adapted to the furnace body and / or tuyere of the blast furnace, Injecting the gas into the furnace body and / or tuyere of the blast furnace; 2. The method for producing steel using a blast furnace and converter based on carbon circulation according to claim 1.

8. The heat required for heating the gas heating device is provided by the combustion of gas in the gas pipeline network, The gas in the gas pipeline network includes blast furnace gas and / or analysis gas from the blast furnace. nothing, The method for producing steel using a blast furnace and converter based on carbon circulation according to claim 7.

9. The decarbonization treatment may be a dry decarbonization treatment or a wet decarbonization treatment, When the decarbonization treatment is a dry decarbonization treatment, the CO ２ Concentration is 95% or less The analyzed gas is merged into a gas pipeline connected to the blast furnace, When the decarbonization treatment is a wet decarbonization treatment, the CO ２ Concentration is above 95% The analysis gas is subjected to CCUS processing. The method for producing steel using a blast furnace and converter based on carbon circulation according to claim 7.

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