A carbon reduction system for a long-process coastal iron and steel enterprise

Abstract

The application relates to a carbon reduction system for a long-process coastal steel enterprise, comprising the following sections: a marine wind power generation section (1), a seawater desalination section (2), a concentrated brine concentration and refining section (3), a chlor-alkali section (4), a liquid chlorine production section (5), an alkali liquor preparation section (6), a blast furnace smelting section (7), a blast furnace gas power generation section (8), a blast furnace gas alkali injection dechlorination section (9), a carbon dioxide capture section (10), a carbon dioxide hydrogenation methanol production section (11), a steel slag carbon sequestration section (12), a soda ash production section (13) and a blast furnace gas upgraded gas section (14). The application takes advantage of the geographical location of the coastal steel enterprise, develops clean power, realizes self-sufficiency of part of the material medium in the enterprise through technology integration, reduces carbon dioxide emissions, realizes carbon dioxide consumption and utilization, and is beneficial to the low-carbon green high-quality development of the blast furnace long process.

Description

Technical Field

[0001] This application relates to the steel industry, and more particularly to a carbon reduction system for coastal long-process steel enterprises. Background Technology

[0002] The steel industry is a pillar industry of the national economy, but it is also a major pollutant and carbon emitter. The steel industry accounts for about 16% of the country's total carbon emissions, of which carbon dioxide emissions from the ironmaking system account for more than 80% of the total emissions, especially from the blast furnace process.

[0003] The International Energy Agency (IEA)'s 2020 Steel Technology Roadmap projects that by 2050, even with conventional emission reduction measures such as process improvements, efficiency enhancements, and energy and raw material substitution, the steel industry will still have 34% of its carbon emissions remaining. Even with a major breakthrough in direct hydrogen reduction (DRI) technology, the remaining carbon emissions will still exceed 8%. The 2022 "China Steel Industry Low-Carbon Technology Development Roadmap" clarifies the technological path for the low-carbon transformation of China's steel industry. Through system energy efficiency improvements, resource recycling, process optimization and innovation, breakthroughs in smelting processes, and product iteration and upgrading, the steel industry will have the technological capability to reduce CO2 emission intensity per ton of steel by 90% compared to 2020.

[0004] Given that technological innovation in steel manufacturing processes is insufficient to reduce carbon emissions, it is imperative to strengthen collaborative innovation with related industries, actively explore technologies and methods for end-of-pipe carbon dioxide treatment, and organize integrated carbon dioxide capture and utilization projects. Therefore, building a cross-industry "low-carbon emission" ecosystem by collaborating with related industries is crucial, building upon the existing blast furnace-converter long-process smelting model. Simultaneously, most coastal areas of my country face freshwater scarcity, making the resolution of this constraint paramount for the survival and development of enterprises. Summary of the Invention

[0005] In order to solve the above-mentioned technical problems, or at least partially solve the above-mentioned technical problems, this application provides a carbon reduction system for coastal long-process steel enterprises.

[0006] Firstly, this application provides a carbon reduction system for a coastal long-process steel enterprise, comprising: an offshore wind power generation section, a seawater desalination section, a concentrated brine concentration and refining section, a chlor-alkali section, a liquid chlorine production section, an alkali preparation section, a blast furnace smelting section, a blast furnace gas power generation section, a blast furnace gas alkali injection and dechlorination section, a carbon dioxide capture section, a carbon dioxide hydrogenation to methanol section, a steel slag carbon fixation section, a soda ash production section, and a blast furnace gas upgrading section, wherein the chlor-alkali section is connected to the offshore wind power generation section, the concentrated brine concentration and refining section, and the liquid chlorine production section. The alkaline solution preparation section is connected to the carbon dioxide hydrogenation to methanol section; the seawater desalination section is connected to the concentrated brine refining section; the alkaline solution preparation section is connected to the blast furnace gas injection dechlorination section; the blast furnace smelting section is connected to the blast furnace gas power generation section; the blast furnace gas injection dechlorination section is connected to both the blast furnace gas power generation section and the carbon dioxide capture section; and the carbon dioxide capture section is connected to the carbon dioxide hydrogenation to methanol section, the steel slag carbon fixation section, the soda ash production section, and the blast furnace gas upgrading section.

[0007] Preferably, the offshore wind power generation section includes an offshore wind power generation device, which is used to generate electricity using offshore wind power.

[0008] Preferably, the seawater desalination section includes a seawater desalination device for performing seawater desalination.

[0009] Preferably, the concentrated brine concentration and refining section includes a concentrated brine concentration and refining device, which is used to concentrate and refine concentrated brine to saturated brine.

[0010] Preferably, the chlor-alkali section includes a chlor-alkali unit for producing chlor-alkali and producing hydrogen as a byproduct.

[0011] Preferably, the alkali solution preparation section includes an alkali solution preparation device, which is used to prepare alkali solution.

[0012] Preferably, the blast furnace gas power generation section includes a blast furnace gas residual pressure turbine power generation device, which is used to generate electricity using the pressure energy and thermal energy of blast furnace gas.

[0013] Preferably, the blast furnace gas injection dechlorination section includes a blast furnace gas injection dechlorination tower, which is used for blast furnace gas injection dechlorination.

[0014] Preferably, the carbon dioxide capture section includes a carbon dioxide capture device for capturing carbon dioxide.

[0015] Preferably, the carbon dioxide hydrogenation to methanol section includes a carbon dioxide hydrogenation to methanol unit, which is used to produce methanol; the steel slag carbon fixation section includes a steel slag carbon fixation unit, which is used to absorb and fix carbon dioxide; and the soda ash production section includes a combined process soda ash production unit, which is used to absorb carbon dioxide to produce soda ash.

[0016] The technical solutions provided in this application have the following advantages compared with the prior art:

[0017] The carbon reduction system provided in this application provides a carbon reduction system for coastal long-process steel enterprises. By leveraging the geographical advantages of coastal steel enterprises, developing clean power, and achieving self-sufficiency in some material media within the enterprise through technological integration, carbon dioxide emissions are reduced. At the same time, carbon dioxide is utilized and absorbed, which is conducive to the low-carbon, green, and high-quality development of long-process blast furnace steel. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of a carbon reduction system for a coastal long-process steel enterprise, provided as an embodiment of this application. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] Figure 1 This is a schematic diagram of a carbon reduction system for a coastal long-process steel enterprise, provided as an embodiment of this application.

[0023] This application provides a carbon reduction system for a coastal long-process steel enterprise, comprising: an offshore wind power generation section 1, a seawater desalination section 2, a concentrated brine concentration and refining section 3, a chlor-alkali section 4, a liquid chlorine production section 5, an alkali preparation section 6, a blast furnace smelting section 7, a blast furnace gas power generation section 8, a blast furnace gas alkali injection and dechlorination section 9, a carbon dioxide capture section 10, a carbon dioxide hydrogenation to methanol section 11, a steel slag carbon fixation section 12, a soda ash production section 13, and a blast furnace gas upgrading section 14. The chlor-alkali section 4 is connected to the offshore wind power generation section 1, the concentrated brine concentration and refining section 3, the liquid chlorine production section 5, and the blast furnace gas upgrading section 14. The alkali preparation section 6 is connected to the carbon dioxide hydrogenation to methanol section 11; the seawater desalination section 2 is connected to the concentrated brine refining section 3; the alkali preparation section 6 is connected to the blast furnace gas injection alkali dechlorination section 9; the blast furnace smelting section 7 is connected to the blast furnace gas power generation section 8; the blast furnace gas injection alkali dechlorination section 9 is connected to both the blast furnace gas power generation section 8 and the carbon dioxide capture section 10; and the carbon dioxide capture section 10 is connected to the carbon dioxide hydrogenation to methanol section 11, the steel slag carbon fixation section 12, the soda ash production section 13, and the blast furnace gas upgrading section 14.

[0024] Specifically, the chlor-alkali section 4 utilizes clean electricity generated by the offshore wind power generation section 1 to electrolyze saturated brine produced in the concentrated brine refining section 3; the caustic soda produced by the electrolysis of the chlor-alkali section 4 is used as a raw material for preparing NaOH alkali solution in the alkali solution preparation section 6, and is also used for blast furnace gas injection alkali dechlorination purification in the blast furnace gas injection alkali dechlorination section 9; the hydrogen produced by the electrolysis of the chlor-alkali section 4 is used in the blast furnace smelting section 7, and the hydrogen produced by the electrolysis of the chlor-alkali section 4, together with the carbon dioxide collected in the carbon dioxide capture section 10, is used in the carbon dioxide hydrogenation to methanol production section 11 to produce methanol; the carbon dioxide from the carbon dioxide capture section 10 can also be used in the steel slag carbon fixation section 12 or, together with the saturated brine produced in the concentrated brine refining section 3, for the soda ash production section 13; the blast furnace gas upgrading gas obtained from the carbon dioxide capture section 10 is used by downstream high-calorific-value gas users; the chlorine produced by the electrolysis of the chlor-alkali section 4 is used in the liquid chlorine production section 5 to produce liquid chlorine for export using a medium-pressure or high-pressure method.

[0025] Specifically, the offshore wind power generation section 1 includes an offshore wind power generation device, which is used to generate electricity using offshore wind power.

[0026] Specifically, the seawater desalination section 2 includes a seawater desalination device for performing seawater desalination.

[0027] Specifically, the concentrated brine concentration and refining section 3 includes a concentrated brine concentration and refining device, which is used to concentrate and refine concentrated brine to saturated brine.

[0028] Specifically, the chlor-alkali section 4 includes a chlor-alkali unit, which is used to produce chlor-alkali and byproduct hydrogen gas.

[0029] Specifically, the alkali preparation section 6 includes an alkali preparation device, which is used to prepare alkali solution.

[0030] Specifically, the blast furnace gas power generation section 8 includes a blast furnace gas residual pressure turbine power generation device, which is used to generate electricity using the pressure energy and heat energy of blast furnace gas.

[0031] Specifically, the blast furnace gas injection dechlorination section 9 includes a blast furnace gas injection dechlorination tower, which is used for blast furnace gas injection dechlorination.

[0032] Specifically, the carbon dioxide capture section 10 includes a carbon dioxide capture device for capturing carbon dioxide. The capture technology can be either alkanolamine solution chemical absorption or PSA pressure swing adsorption.

[0033] Specifically, the carbon dioxide hydrogenation to methanol section 11 includes a carbon dioxide hydrogenation to methanol unit, which is used to produce methanol.

[0034] Specifically, the steel slag carbon fixation section 12 includes a steel slag carbon fixation device, which is used to absorb and fix carbon dioxide.

[0035] Specifically, the soda ash production section 13 includes a combined process soda ash production unit, which is used to absorb carbon dioxide to produce soda ash.

[0036] Example 1

[0037] A coastal integrated steel mill with a capacity of 5 million tons consumes approximately 18 million tons of fresh water annually. Its daily blast furnace pig iron production is 12,500 tons (t), and its blast furnace gas production per ton of pig iron is 1350 Nm³. 3 The CO2 content in the blast furnace gas is approximately 24%, with an annual operating rate of about 96%. The annual CO2 carried out from the blast furnace gas is 2.8 million tons; the annual steel slag production is 600,000 tons. The company has constructed a 100,000-ton blast furnace gas carbon dioxide capture device.

[0038] Section 2 of the seawater desalination plant, with a daily production capacity of 10,000 tons of fresh water, will produce 3.6 million tons of water annually, meeting nearly 20% of the steel company's total water needs. The raw water for desalination has a salinity of 3.2%. Based on the desalination plant's operational technology, 3.03 million tons of 7% brine will be produced annually as a byproduct. This brine will be further refined in section 3 to produce approximately 800,000 tons of saturated brine. If the 10% saturated brine is used in section 4 of the chlor-alkali plant, based on the current salt consumption of 1.51 tons per ton of caustic soda, 14,000 tons of caustic soda can be produced annually, along with a byproduct of 351 tons (equivalent to 3.9 million Nm³). 3 The process generates 173,000 tons of soda ash and consumes 72,000 tons of CO2 annually. The remaining 90% of the saturated brine is used in soda ash production section 13. If 100% of the hydrogen produced as a byproduct of chlor-alkali electrolysis is used in methanol production section 11 via carbon dioxide hydrogenation, 2,600 tons of CO2 can be fixed, with 1,870 tons of methanol produced as a byproduct. In steel slag carbon sequestration section 12, the carbon sequestration capacity is 50 kg per ton of steel; 600,000 tons of steel slag can sequester 30,000 tons of carbon, completely absorbing the remaining 25,400 tons. The combined annual carbon dioxide consumption from methanol production via carbon dioxide hydrogenation, steel slag carbon sequestration, and soda ash production is 100,000 tons, accounting for approximately 3.6% of the CO2 carried over from the blast furnace gas, demonstrating a good carbon reduction effect.

[0039] Based on the current electricity consumption of 2350 kWh per ton of caustic soda, the annual electricity consumption is 33 million kWh. Currently, the largest commercial single-unit capacity wind turbine is an 11 MW wind turbine, with a designed annual power generation of 38.2 million kWh per turbine. Section 1 only needs to be equipped with one 11 MW wind turbine.

[0040] The blast furnace gas injection dechlorination section 9 uses 10% NaOH alkali solution, with a consumption rate of 1.8 t / h, consuming 1500 t of caustic soda (NaOH) annually. After deducting the 1500 t of caustic soda consumed in the blast furnace gas injection dechlorination, the remaining 12,500 tons of caustic soda can be sold externally. The 12,500 tons of chlorine gas are pressurized and cooled in section 5 using either medium- or high-pressure methods to produce liquid chlorine for external sale. This also reduces the company's need for external purchases of caustic soda (NaOH) and the need for processing concentrated brine from seawater desalination.

[0041] Example 2

[0042] A coastal integrated steel mill with a capacity of 5 million tons consumes approximately 18 million tons of fresh water annually. Its daily blast furnace pig iron production is 12,500 tons (t), and its blast furnace gas production per ton of pig iron is 1350 Nm³. 3 The CO2 content in the blast furnace gas is approximately 24%, with an annual operating rate of about 96%. The annual CO2 carried out from the blast furnace gas is 2.8 million tons; the annual steel slag production is 600,000 tons. The company has constructed a 200,000-ton blast furnace gas carbon dioxide capture device.

[0043] Section 2 of the seawater desalination plant, with a daily production capacity of 20,000 tons of fresh water, will produce 7.2 million tons of water annually, meeting nearly 40% of the steel company's total water needs. The raw water used for desalination has a salinity of 3.2%. Based on the desalination plant's operational technology, 6.06 million tons of 7% brine will be produced annually as a byproduct. This brine, after concentration and refining in section 3, can yield approximately 1.6 million tons of saturated brine. If the 30% saturated brine is used in section 4 of the chlor-alkali plant, based on the current salt consumption of 1.51 tons per ton of caustic soda, 84,200 tons of caustic soda can be produced annually, along with a byproduct of 2,106 tons (equivalent to 23.42 million Nm³). 3 The process involves producing hydrogen and 74,700 tons of chlorine; the remaining 70% saturated brine is used in soda ash production section 13, resulting in an annual output of 269,000 tons of soda ash and the consumption of 112,000 tons of CO2. If 100% of the hydrogen produced as a byproduct of chlor-alkali electrolysis is used in the blast furnace hydrogen-rich smelting section 7, based on an injection rate of 20 Nm³ per ton of iron... 3 Based on a reduction of 8 kg / tHM in the coke ratio, the hydrogen produced as a byproduct of electrolysis can last for approximately 94 days, reducing coke consumption by 9,400 tons and CO2 emissions by 30,000 tons. The steel slag carbonization section has a capacity of 80 kg of carbon sequestration per ton of steel, meaning 600,000 tons of steel slag can sequester 48,000 tons of carbon. The combined annual carbon dioxide consumption from hydrogen-rich blast furnace smelting, steel slag carbonization, and soda ash production is 190,000 tons, accounting for approximately 6.8% of the total CO2 carried over from blast furnace gas, demonstrating a significant carbon reduction effect.

[0044] Based on the current electricity consumption of 2350 kWh per ton of caustic soda, the annual electricity consumption is approximately 200 million kWh. Currently, the largest commercial single-unit capacity wind turbine is an 11 MW wind turbine, with a designed annual power generation of 38.2 million kWh per turbine. Section 1 only needs to be equipped with 5 11 MW wind turbines.

[0045] The blast furnace gas injection dechlorination section 9 uses 10% NaOH alkali solution, with a consumption rate of 1.8 t / h, consuming 1500 t of caustic soda (NaOH) annually. After deducting the 1500 t of caustic soda consumed in the blast furnace gas injection dechlorination, the remaining 82,700 tons of caustic soda can be sold externally. 74,700 tons of chlorine gas are pressurized and cooled in section 5 using medium- or high-pressure methods to produce liquid chlorine for external sale. This also reduces the company's need for external purchases of caustic soda (NaOH) and the need for processing concentrated brine from seawater desalination.

[0046] The carbon reduction system provided in this application provides a carbon reduction system for coastal long-process steel enterprises. By leveraging the geographical advantages of coastal steel enterprises, developing clean power, and achieving self-sufficiency in some material media within the enterprise through technological integration, carbon dioxide emissions are reduced. At the same time, carbon dioxide is utilized and absorbed, which is conducive to the low-carbon, green, and high-quality development of long-process blast furnace steel.

[0047] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0048] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A carbon reduction system for coastal long-process steel enterprises, characterized in that, include: The offshore wind power generation section (1), seawater desalination section (2), concentrated brine concentration and refining section (3), chlor-alkali section (4), liquid chlorine production section (5), alkali preparation section (6), blast furnace smelting section (7), blast furnace gas power generation section (8), blast furnace gas alkali injection and dechlorination section (9), carbon dioxide capture section (10), carbon dioxide hydrogenation to methanol section (11), steel slag carbon fixation section (12), soda ash production section (13), and blast furnace gas upgrading section (14), wherein the chlor-alkali section (4) is connected to the offshore wind power generation section (1), the concentrated brine concentration and refining section (3), the liquid chlorine production section (5), the alkali preparation section (6), and the blast furnace gas upgrading section (14). The carbon dioxide hydrogenation to methanol production section (11) is connected, the seawater desalination section (2) is connected to the concentrated brine concentration and refining section (3), the alkali preparation section (6) is connected to the blast furnace gas injection alkali dechlorination section (9), the blast furnace smelting section (7) is connected to the blast furnace gas power generation section (8), the blast furnace gas injection alkali dechlorination section (9) is connected to the blast furnace gas power generation section (8) and the carbon dioxide capture section (10) respectively, and the carbon dioxide capture section (10) is connected to the carbon dioxide hydrogenation to methanol production section (11), the steel slag carbon fixation section (12), the soda ash production section (13) and the blast furnace gas upgrading section (14) respectively; The concentrated brine concentration and refining section (3) includes a concentrated brine concentration and refining device, which is used to concentrate and refine concentrated brine to saturated brine. The chlor-alkali section (4) includes a chlor-alkali unit, which is used to produce chlor-alkali and byproduct hydrogen. The alkali preparation section (6) includes an alkali preparation device, which is used to prepare alkali solution; The blast furnace gas injection dechlorination section (9) includes a blast furnace gas injection dechlorination tower, which is used for blast furnace gas injection dechlorination. The carbon dioxide capture section (10) includes a carbon dioxide capture device for capturing carbon dioxide. The carbon dioxide hydrogenation to methanol section (11) includes a carbon dioxide hydrogenation to methanol unit, which is used to produce methanol; the steel slag carbon fixation section (12) includes a steel slag carbon fixation unit, which is used to absorb and fix carbon dioxide; the soda ash production section (13) includes a combined process soda ash production unit, which is used to absorb carbon dioxide to produce soda ash. The chlor-alkali section (4) uses the electricity generated by the offshore wind power generation section (1) to electrolyze the saturated brine obtained in the concentrated brine concentration and refining section (3); the caustic soda produced by the electrolysis of the chlor-alkali section (4) is used as the raw material for the preparation of alkali solution in the alkali solution preparation section (6) and is used for the blast furnace gas injection alkali dechlorination purification in the blast furnace gas injection alkali dechlorination section (9); the hydrogen produced by the electrolysis of the chlor-alkali section (4) is used in the blast furnace smelting section (7); the hydrogen produced by the electrolysis of the chlor-alkali section (4) and the carbon dioxide collected in the carbon dioxide capture section (10) are used to perform carbon dioxide hydrogenation to methanol production in the carbon dioxide hydrogenation to methanol section (11); the chlorine produced by the electrolysis of the chlor-alkali section (4) is used to produce liquid chlorine in the liquid chlorine production section (5); The carbon dioxide captured in the carbon dioxide capture section (10) is also used in the steel slag carbon fixation section (12) or the saturated brine obtained from the concentrated brine concentration and refining section (3) is used in the soda ash production section (13); the blast furnace gas upgrading gas obtained from the carbon dioxide capture section (10) is used by downstream high-calorific-value gas users; the carbon dioxide capture device in the carbon dioxide capture section (10) uses the alkanolamine solution chemical absorption method or the PSA pressure swing adsorption method to capture carbon dioxide.

2. The carbon reduction and decarbonization system for coastal long-process steel enterprises according to claim 1, characterized in that, The offshore wind power generation section (1) includes an offshore wind power generation device, which is used to generate electricity by offshore wind power.

3. The carbon reduction and decarbonization system for coastal long-process steel enterprises according to claim 1, characterized in that, The seawater desalination section (2) includes a seawater desalination device for performing seawater desalination.

4. The carbon reduction and decarbonization system for coastal long-process steel enterprises according to claim 1, characterized in that, The blast furnace gas power generation section (8) includes a blast furnace gas residual pressure turbine power generation device, which is used to generate electricity using the pressure energy and heat energy of blast furnace gas.

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