Product carbon footprint calculation method considering scrap steel circulation

Abstract

The invention relates to the technical field of steel production, and provides a product carbon footprint calculation method considering scrap steel circulation, which comprises the following steps: step 1, calculating the direct emission of greenhouse gas; 2, calculating the total emission amount of the greenhouse gas in the life cycle; and step 3, considering a 1t functional unit product carbon footprint in a waste steel circulation stage. According to the method, comprehensiveness and accuracy are improved, and by integrating all direct emission sources, traditional emission calculation is covered, and emission reduction contribution of carbon sequestration products which are usually ignored is further included. The comprehensiveness enables the carbon footprint calculation to truly reflect the actual environmental influence of the enterprise or the production process. Besides, more accurate carbon footprint data support enterprises and policy formulators to make more effective strategies and measures, such as investment in more efficient technologies or optimization of resource allocation, thereby reducing environmental impact, promoting practice of circular economy, and reducing requirements of the industry for raw materials and environmental footprints thereof.

Description

Technical Field

[0001] The invention relates to the technical field of steel production, and in particular to a method for calculating the carbon footprint of a product taking into account the recycling of scrap steel. Background Art

[0002] Existing methods for calculating the carbon footprint of steel production are generally insufficient to fully reflect the environmental benefits of scrap steel recycling and reuse, resulting in an incomplete and inaccurate assessment of the environmental impact of the product throughout its life cycle.

[0003] Therefore, the purpose of this invention is to develop a comprehensive and accurate method for calculating the carbon footprint of steel products throughout their life cycle, which can comprehensively consider various emission sources and carbon sequestration opportunities, ensure the scientificity and effectiveness of carbon management strategies, and thus help enterprises and policymakers to more effectively respond to environmental challenges and promote the sustainable development of the steel industry.

[0004] Improved comprehensiveness and accuracy: Previous technologies usually only define the properties of direct carbon emissions from steel products, but lack guidance on how to calculate direct emissions. This invention proposes a method to calculate direct emissions such as fossil fuel combustion, raw material use, and carbon sequestration from carbon sequestration products during steel production, accurately quantifying direct greenhouse gas emissions, thereby more comprehensively and accurately assessing direct carbon emissions, thereby helping companies or policymakers better understand and manage carbon footprints.

[0005] Completeness of carbon emission calculation: By considering the environmental benefits brought by co-products during the production process, the present invention can more comprehensively assess the overall carbon footprint of steel products, reflecting the actual environmental impact of all relevant activities.

[0006] Incorporating the carbon emission reduction potential of scrap steel recovery and recycling: The present invention places special emphasis on the carbon emission reduction potential of scrap steel recovery and recycling stages. By calculating the life cycle inventory (LCI_EOL) of the scrap steel recovery stage, the environmental benefits of scrap steel recovery are explicitly included in the total carbon footprint, thereby improving the accuracy of the assessment.

[0007] Through these improvements, the present invention can provide a more accurate and practical method for calculating the carbon footprint of steel products during their life cycle, which can help companies and policy makers to more effectively formulate emission reduction strategies and environmental protection measures. Summary of the invention

[0008] In view of the shortcomings of the prior art, the present invention provides a method for calculating the carbon footprint of a product taking into account the recycling of scrap steel, which solves the problem that the diaphragm is easily deformed or damaged in a high-temperature environment, resulting in a decrease in the suppression effect, thereby affecting the final imaging effect, and the problem of insufficient applicability and effect in different environments.

[0009] To achieve the above objectives, the present invention is implemented by the following technical solutions: A method for calculating the carbon footprint of a product considering the recycling of scrap steel, comprising the following steps:

[0010] Step 1: Calculate direct greenhouse gas emissions;

[0011] Step 2: Calculate the total amount of greenhouse gas emissions during the life cycle;

[0012] Step 3: Consider the carbon footprint of 1 t functional unit product in the scrap steel recycling stage.

[0013] Preferably, the calculation of direct greenhouse gas emissions in step 1 comprises the following steps:

[0014] S1. Calculate greenhouse gas emissions from fossil fuel combustion A;

[0015] S2. Calculate greenhouse gas emissions B during the use of raw materials and auxiliary materials;

[0016] S3. Calculate the carbon sequestration amount C of the carbon sequestration product;

[0017] S4. Calculate direct greenhouse gas emissionsb F .

[0018] Preferably, the calculation formula for the greenhouse gas emissions A from the combustion of S1 fossil fuels is:

[0019] A=α T，i ×EF

[0021] A (greenhouse gas emissions from fossil fuel combustion): CO2 emissions from fossil fuel combustion based on functional unit F, which quantifies the direct CO2 emissions per unit of product during the production process;

[0022] α T，i (Direct consumption): represents the direct consumption of raw materials or energy for each functional unit of unit process i in the product system;

[0024] EF (Emission Factor): It indicates the amount of carbon dioxide produced when burning one ton of fossil fuel, in tons of carbon dioxide / ton (tCO2 / t), and is used to quantify the carbon emission effect of fossil fuel combustion under standard conditions;

[0025] The calculation formula of EF (emission factor) is:

[0026]

[0027] NCVar (lower calorific value): refers to the received lower calorific value of fossil fuels, in gigajoules per ton (GJ / t);

[0028] CC (Carbon content per unit calorific value): indicates the amount of carbon contained in the unit calorific value, in tons of carbon / gigajoule (tC / GJ);

[0029] OF (Carbon oxidation rate): usually takes a default value, indicating the proportion of carbon oxidized during fossil fuel combustion, expressed as a percentage (%);

[0030] 44 / 12: is the ratio of the relative molecular weights of carbon dioxide to carbon, used to convert the mass of carbon to the corresponding mass of carbon dioxide.

[0031] Preferably, the calculation formula for greenhouse gas emissions B during the use of raw materials and auxiliary materials in S2 is:

[0032]

[0033] B (GHG emissions from the use of raw and auxiliary materials): This value represents the amount of greenhouse gases released during the use of raw and auxiliary materials (including carbon-containing materials) related to each functional unit (F) in steel production;

[0034] α T，i (Direct consumption): represents the direct consumption of raw materials or energy for each functional unit of unit process i in the product system;

[0036] C ar : refers to the carbon content in raw materials and auxiliary materials;

[0037] 44 / 12: is the ratio of the relative molecular weights of carbon dioxide to carbon, used to convert the mass of carbon to the corresponding mass of carbon dioxide.

[0038] Preferably, the calculation formula for the carbon fixation amount C of the carbon fixation product in S3 is:

[0039]

[0040] C (Carbon Sequestration): represents the carbon sequestration of carbon sequestration products based on functional unit F;

[0041] Mo (output carbon-containing materials produced): the total amount of carbon-containing materials output during the production process;

[0042] CCo (carbon content of output material): refers to the weight of carbon contained in each unit of output material;

[0043] 44 / 12: The relative molecular weight ratio of carbon dioxide to carbon, used to convert the mass of carbon to the corresponding mass of carbon dioxide.

[0044] Preferably, the direct greenhouse gas emissions in S4 are F The calculation formula is:

[0045] bF =ΣA×ΣB-ΣC

[0046] b F (Direct greenhouse gas emissions from product production): represents the total emissions of all greenhouse gases g directly generated in the product production process based on the functional unit F;

[0047] A (Greenhouse gas emissions from fossil fuel combustion): The calculation includes all greenhouse gas emissions directly emitted from the combustion of fossil fuels during the production process;

[0048] B (greenhouse gas emissions during the use of raw materials and auxiliary materials): all greenhouse gas emissions generated during the use of raw materials and auxiliary materials;

[0049] C (Carbon fixation amount of carbon fixation products): The amount of carbon fixed by carbon fixation products during the production process.

[0050] Preferably, the calculation formula for the total amount of greenhouse gas emissions during the life cycle in step 2 is:

[0051] X=b F +Σα T,i b T,i,g -Σb T,i, e i,g

[0052] X: Cumulative emissions of a greenhouse gas g based on functional unit F;

[0053] F (functional unit): a commonly specified unit of measurement for a product;

[0054] g: Types of greenhouse gases, including carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), sulfur hexafluoride (SF6), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), nitrogen trifluoride (NF3), etc.;

[0055] b F : The amount of greenhouse gas g emitted directly during the production process of the product based on the functional unit F;

[0056] Σα T,i b T,i,g : The sum of the direct consumption of raw materials, auxiliary materials, energy, etc. per functional unit in the unit process i of the product system and the product of the upstream implicit greenhouse gas emissions caused by these consumptions;

[0057] Σb T,i, e i,g : The environmental benefits of co-products in the steelmaking process, i.e. the greenhouse gas emissions that these co-products replace from the production of other materials.

[0058] Preferably, the carbon footprint of 1 t functional unit product in the scrap steel recycling stage in step 3 comprises the following steps:

[0059] S1. Calculate the life cycle inventory of scrap steel recycling stages;

[0060] S2. Calculate the carbon footprint value of the product.

[0061] Preferably, the calculation formula for the life cycle inventory of the scrap steel recycling stage in S1 is:

[0062] LCI EOL =(RR-S)(X pr -X re )·Y

[0063] LCI EOL (Life cycle inventory of scrap steel recycling stage): represents a quantitative indicator to measure the environmental impact of scrap steel recycling efficiency;

[0064] RR (Scrap Recovery Rate): It indicates the ratio of the amount of scrap steel recovered to the total amount of scrap steel after the steel production process is completed;

[0065] S (Scrap Addition): This refers to the amount of scrap steel used directly in the production of new steel products;

[0066] X pr (Life Cycle Inventory for Steel Products Using Whole Iron Ore): represents the environmental impact assessment of steel production using raw iron ore;

[0067] X re (Life Cycle Inventory of Steel Products Using All Scrap): represents the environmental impact assessment of using scrap steel as raw material to produce steel;

[0068] Y (scrap steel utilization rate): indicates the proportion of scrap steel converted into steel during the recycling of scrap steel.

[0069] Preferably, the calculation formula for the carbon footprint value of the product in S2 is:

[0070] W=Σ{X-LCI EOL}·C i

[0071] W (product carbon footprint): represents the total amount of greenhouse gas emissions generated by a product during its entire life cycle, from raw material acquisition to final disposal, adjusted for global warming potential;

[0072] X: represents the cumulative emission of a certain greenhouse gas based on functional unit F without considering the recycling of scrap steel;

[0073] LCI EOL(Life cycle inventory of scrap steel recycling): measures the contribution of scrap steel recycling and reuse in reducing carbon emissions, which is deducted from total emissions;

[0074] C i (Global Warming Potential): Each greenhouse gas has a different global warming potential depending on its contribution to the Earth's greenhouse effect.

[0075] The present invention provides a method for calculating the carbon footprint of a product taking into account the recycling of scrap steel. It has the following beneficial effects:

[0076] 1. Improved comprehensiveness and accuracy of the present invention: By integrating various direct emission sources, the present invention not only covers traditional emission calculations, but also includes the emission reduction contribution of carbon sequestration products that are often overlooked. This comprehensiveness enables carbon footprint calculations to truly reflect the actual environmental impact of an enterprise or production process. In addition, more accurate carbon footprint data supports enterprises and policymakers to make more effective strategies and measures, such as investing in more efficient technologies or optimizing resource allocation, thereby reducing environmental impact.

[0077] 2. The completeness of the carbon emission calculation of the present invention and the comprehensive assessment of environmental impact: Including the carbon emission reduction potential of co-products in the calculation not only improves the completeness of the carbon footprint assessment, but also helps the industry realize the importance of waste reuse and resource recycling.

[0078] 3. Accurate quantification of the contribution of scrap steel recycling by the present invention: By accurately quantifying the carbon reduction benefits of scrap steel recycling, the present invention not only enhances the incentive mechanism for scrap steel recycling, but also promotes the practice of a circular economy, reducing the industry’s demand for raw materials and its environmental footprint. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] Figure 1 is a flow chart of the method of the present invention;

[0080] Figure 2 The figure is a flow chart of the calculation method of the present invention. DETAILED DESCRIPTION

[0081] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0082] Example:

[0083] Please refer to the attached Figure 1 -Attached Figure 2The embodiment of the present invention provides a method for calculating the carbon footprint of a product taking into account the recycling of scrap steel, comprising the following steps:

[0084] Step 1: Calculate the direct greenhouse gas emissions. Multiply the direct consumption of each functional unit in the product system by the emission factor EF to calculate the greenhouse gas emissions A from fossil fuel combustion. The specific steps are as follows:

[0085] S1. Calculate the greenhouse gas emissions A from fossil fuel combustion using the following formula:

[0086] A=α T，i ×EF

[0088] A (greenhouse gas emissions from fossil fuel combustion): CO2 emissions from fossil fuel combustion based on functional unit F, which quantifies the direct CO2 emissions per unit of product during the production process;

[0089] α T，i (Direct consumption): represents the direct consumption of raw materials or energy for each functional unit of unit process i in the product system;

[0091] EF (Emission Factor): It indicates the amount of carbon dioxide produced when burning one ton of fossil fuel, in tons of carbon dioxide / ton (tCO2 / t), and is used to quantify the carbon emission effect of fossil fuel combustion under standard conditions;

[0092] The calculation formula of EF (emission factor) is:

[0093]

[0094] NCVar (lower calorific value): refers to the received lower calorific value of fossil fuels, in gigajoules per ton (GJ / t);

[0095] CC (Carbon content per unit calorific value): indicates the amount of carbon contained in the unit calorific value, in tons of carbon / gigajoule (tC / GJ);

[0096] OF (Carbon oxidation rate): usually takes a default value, indicating the proportion of carbon oxidized during fossil fuel combustion, expressed as a percentage (%);

[0097] 44 / 12: is the relative molecular weight ratio of carbon dioxide to carbon, used to convert the mass of carbon to the corresponding mass of carbon dioxide;

[0098] S2. Calculate the greenhouse gas emissions B during the use of raw and auxiliary materials. In order to comprehensively evaluate the carbon emissions of all relevant links in the steel production process, it is necessary to consider the greenhouse gases generated during the use of raw and auxiliary materials. The formula is:

[0099]

[0100] B (GHG emissions from the use of raw and auxiliary materials): This value represents the amount of greenhouse gases released during the use of raw and auxiliary materials (including carbon-containing materials) related to each functional unit (F) in steel production;

[0101] α T，i (Direct consumption): represents the direct consumption of raw materials or energy for each functional unit of unit process i in the product system;

[0103] C ar : refers to the carbon content in raw materials and auxiliary materials;

[0104] 44 / 12: is the relative molecular weight ratio of carbon dioxide to carbon, used to convert the mass of carbon to the corresponding mass of carbon dioxide;

[0105] S3. Calculate the carbon sequestration amount C of carbon sequestration products. In steel production and other industrial processes, certain products or by-products can fix a large amount of carbon, thereby reducing the total greenhouse gas emissions. The calculation formula is:

[0106]

[0107] C (Carbon Sequestration): represents the carbon sequestration of carbon sequestration products based on functional unit F;

[0108] Mo (output carbon-containing materials produced): the total amount of carbon-containing materials output during the production process;

[0109] CCo (carbon content of output material): refers to the weight of carbon contained in each unit of output material;

[0110] 44 / 12: The relative molecular weight ratio of carbon dioxide to carbon, used to convert the mass of carbon into the corresponding mass of carbon dioxide;

[0111] S4. Calculate the direct greenhouse gas emissions bF. When evaluating the environmental impact of industrial products such as steel, it is crucial to calculate the greenhouse gas emissions directly generated during the production process of the product. The calculation formula is:

[0112] b F =∑A×∑B-∑C

[0113] b F (Direct greenhouse gas emissions from product production): represents the total emissions of all greenhouse gases g directly generated in the product production process based on the functional unit F;

[0114] A (Greenhouse gas emissions from fossil fuel combustion): The calculation includes all greenhouse gas emissions directly emitted from the combustion of fossil fuels during the production process;

[0115] B (greenhouse gas emissions during the use of raw materials and auxiliary materials): all greenhouse gas emissions generated during the use of raw materials and auxiliary materials;

[0116] C (Carbon fixation amount of carbon fixation products): the amount of carbon fixed by carbon fixation products during the production process;

[0117] Step 2: Calculate the total amount of greenhouse gas emissions during the life cycle. In order to comprehensively evaluate the environmental impact of industrial products such as steel, it is important to consider the sum of all greenhouse gas emissions from raw material procurement to the end of the product life cycle. Add the cumulative amount of greenhouse gases in the upstream process and the emission reduction factor of co-products in the steel manufacturing process to calculate the total emission X of a greenhouse gas during the life cycle. The calculation formula is:

[0118] X=b F +Σα T,i b T,i,g -Σb T,i, e i,g

[0119] X: Cumulative emissions of a greenhouse gas g based on functional unit F;

[0120] F (functional unit): a commonly specified unit of measurement for a product;

[0121] g: Types of greenhouse gases, including carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), sulfur hexafluoride (SF6), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), nitrogen trifluoride (NF3), etc.;

[0122] b F : The amount of greenhouse gas g emitted directly during the production process of the product based on the functional unit F;

[0123] Σα T,i b T,i,g : The sum of the direct consumption of raw materials, auxiliary materials, energy, etc. per functional unit in the unit process i of the product system and the product of the upstream implicit greenhouse gas emissions caused by these consumptions;

[0124] Σb T,i, e i,g : The environmental benefits of co-products in the steelmaking process, i.e. the greenhouse gas emissions these co-products replace from the production of other materials;

[0125] Step 3: Consider the carbon footprint of 1 ton of functional unit product in the scrap steel recycling stage, including the following steps:

[0126] S1. Calculate the life cycle inventory of the scrap steel recycling stage. In the steel production process, the recycling and reuse of scrap steel is an important part of reducing resource consumption and environmental impact. In order to comprehensively evaluate the environmental benefits of scrap steel recycling, it is necessary to calculate the life cycle inventory (LCI) of the scrap steel recycling stage. EOL ), which helps quantify the impact of scrap steel recycling on the overall carbon footprint. Specifically, this solution calculates the life cycle inventory (LCI) of the scrap steel recycling stage based on the scrap steel recycling rate, input volume and scrap steel utilization rate. EOL ) The calculation formula is:

[0127] LCI EOL =(RR-S)(X pr -X re )·Y

[0128] LCI EOL (Life cycle inventory of scrap steel recycling stage): represents a quantitative indicator to measure the environmental impact of scrap steel recycling efficiency;

[0129] RR (Scrap Recovery Rate): It indicates the ratio of the amount of scrap steel recovered to the total amount of scrap steel after the steel production process is completed;

[0130] S (Scrap Addition): This refers to the amount of scrap steel used directly in the production of new steel products;

[0131] X pr (Life Cycle Inventory for Steel Products Using Whole Iron Ore): represents the environmental impact assessment of steel production using raw iron ore;

[0132] X re (Life Cycle Inventory of Steel Products Using All Scrap): represents the environmental impact assessment of using scrap steel as raw material to produce steel;

[0133] Y (Scrap Steel Utilization Rate): indicates the proportion of scrap steel converted into steel in the recycling of scrap steel, that is, the effective utilization of scrap steel;

[0134] S2. Calculate the carbon footprint value of the product. The calculation formula is:

[0135] W=Σ{X-LCI EOL}·C i

[0136] W (product carbon footprint): represents the total amount of greenhouse gas emissions generated by a product during its entire life cycle, from raw material acquisition to final disposal, adjusted for global warming potential;

[0137] X: represents the cumulative emission of a certain greenhouse gas based on functional unit F without considering the recycling of scrap steel;

[0138] LCIEOL (Life cycle inventory of scrap steel recycling): measures the contribution of scrap steel recycling and reuse in reducing carbon emissions, which is deducted from total emissions;

[0139] C i (Global Warming Potential): Each greenhouse gas has a different global warming potential according to its contribution to the global warming effect

[0140] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for calculating the carbon footprint of a product taking into account the recycling of scrap steel, characterized in that: The following steps are involved: Step 1: Calculate direct greenhouse gas emissions; Step 2: Calculate the total amount of greenhouse gas emissions during the life cycle; Step 3: Consider the carbon footprint of 1 t functional unit product in the scrap steel recycling stage.

2. A method for calculating the carbon footprint of a product considering the recycling of scrap steel according to claim 1, characterized in that: The calculation of direct greenhouse gas emissions in step 1 includes the following steps: S1. Calculate greenhouse gas emissions from fossil fuel combustion A; S2. Calculate greenhouse gas emissions B during the use of raw materials and auxiliary materials; S3. Calculate the carbon sequestration amount C of the carbon sequestration product; S4. Calculate direct greenhouse gas emissionsb F .

3. A method for calculating the carbon footprint of a product considering the recycling of scrap steel according to claim 2, characterized in that: The calculation formula for the greenhouse gas emissions A from the combustion of S1 fossil fuels is: A=a T，i ×EF A (greenhouse gas emissions from fossil fuel combustion): CO2 emissions from fossil fuel combustion based on functional unit F, which quantifies the direct CO2 emissions per unit of product during the production process; α T，i (Direct consumption): represents the direct consumption of raw materials or energy for each functional unit of unit process i in the product system; EF (Emission Factor): It indicates the amount of carbon dioxide produced when burning one ton of fossil fuel, in tons of carbon dioxide / ton (tCO2 / t), and is used to quantify the carbon emission effect of fossil fuel combustion under standard conditions; The calculation formula of EF (emission factor) is: NCVar (lower calorific value): refers to the received lower calorific value of fossil fuels, in gigajoules per ton (GJ / t); CC (Carbon content per unit calorific value): indicates the amount of carbon contained in the unit calorific value, in tons of carbon / gigajoule (tC / GJ); OF (Carbon oxidation rate): usually takes a default value, indicating the proportion of carbon oxidized during fossil fuel combustion, expressed as a percentage (%); 44 / 12: is the ratio of the relative molecular weights of carbon dioxide to carbon, used to convert the mass of carbon to the corresponding mass of carbon dioxide.

4. A method for calculating the carbon footprint of a product considering the recycling of scrap steel according to claim 3, characterized in that: The calculation formula for greenhouse gas emissions B during the use of raw materials and auxiliary materials in S2 is: B (GHG emissions from the use of raw and auxiliary materials): This value represents the amount of greenhouse gases released during the use of raw and auxiliary materials (including carbon-containing materials) related to each functional unit (F) in steel production; α T，i (Direct consumption): represents the direct consumption of raw materials or energy for each functional unit of unit process i in the product system; C ar : refers to the carbon content in raw materials and auxiliary materials; 44 / 12: is the ratio of the relative molecular weights of carbon dioxide to carbon, used to convert the mass of carbon to the corresponding mass of carbon dioxide.

5. The method for calculating the carbon footprint of a product considering the recycling of scrap steel according to claim 1, characterized in that: The calculation formula for the carbon fixation amount C of the carbon fixation product in S3 is: C (Carbon Sequestration): represents the carbon sequestration of carbon sequestration products based on functional unit F; Mo (output carbon-containing materials produced): the total amount of carbon-containing materials output during the production process; CCo (carbon content of output material): refers to the weight of carbon contained in each unit of output material; 44 / 12: The relative molecular weight ratio of carbon dioxide to carbon, used to convert the mass of carbon to the corresponding mass of carbon dioxide.

6. The method for calculating the carbon footprint of a product considering the recycling of scrap steel according to claim 1, characterized in that: Direct greenhouse gas emissions in S4b F The calculation formula is: b F =∑A×∑B-∑C b F (Direct greenhouse gas emissions from product production): represents the total emissions of all greenhouse gases g directly generated in the product production process based on the functional unit F; A (Greenhouse gas emissions from fossil fuel combustion): The calculation includes all greenhouse gas emissions directly emitted from the combustion of fossil fuels during the production process; B (greenhouse gas emissions during the use of raw materials and auxiliary materials): all greenhouse gas emissions generated during the use of raw materials and auxiliary materials; C (Carbon fixation amount of carbon fixation products): The amount of carbon fixed by carbon fixation products during the production process.

7. The method for calculating the carbon footprint of a product considering the recycling of scrap steel according to claim 1, characterized in that: The calculation formula for the total amount of greenhouse gas emissions during the life cycle in step 2 is: X=b F +Sa T,i b T,i,g -Sb T,i, e i,g X: Cumulative emissions of a greenhouse gas g based on functional unit F; F (functional unit): a commonly specified unit of measurement for a product; g: Types of greenhouse gases, including carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), sulfur hexafluoride (SF6), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), nitrogen trifluoride (NF3), etc.; b F : The amount of greenhouse gas g emitted directly during the production process of the product based on the functional unit F; Σα T,i b T,i,g : The sum of the direct consumption of raw materials, auxiliary materials, energy, etc. per functional unit in the unit process i of the product system and the product of the upstream implicit greenhouse gas emissions caused by these consumptions; Σb T,i, e i,g : The environmental benefits of co-products in the steelmaking process, i.e. the greenhouse gas emissions that these co-products replace from the production of other materials.

8. The method for calculating the carbon footprint of a product considering the recycling of scrap steel according to claim 1, characterized in that: The carbon footprint of 1 ton functional unit product in the scrap steel recycling stage in step 3 includes the following steps: S1. Calculate the life cycle inventory of scrap steel recycling stages; S2. Calculate the carbon footprint value of the product.

9. A method for calculating the carbon footprint of a product considering the recycling of scrap steel according to claim 8, characterized in that: The calculation formula for the life cycle inventory of the scrap steel recycling stage in S1 is: LCI EOL =(RR-S)(X pr -X re )·Y LCI EOL (Life cycle inventory of scrap steel recycling stage): represents a quantitative indicator to measure the environmental impact of scrap steel recycling efficiency; RR (Scrap Recovery Rate): It indicates the ratio of the amount of scrap steel recovered to the total amount of scrap steel after the steel production process is completed; S (Scrap Addition): This refers to the amount of scrap steel used directly in the production of new steel products; X pr (Life Cycle Inventory for Steel Products Using Whole Iron Ore): represents the environmental impact assessment of steel production using raw iron ore; X re (Life Cycle Inventory of Steel Products Using All Scrap): represents the environmental impact assessment of using scrap steel as raw material to produce steel; Y (scrap steel utilization rate): indicates the proportion of scrap steel converted into steel during the recycling of scrap steel.

10. A method for calculating the carbon footprint of a product considering the recycling of scrap steel according to claim 8, characterized in that: The calculation formula of the carbon footprint value of the product in S2 is: W=Σ{X-LCI EOL }·C i W (product carbon footprint): represents the total amount of greenhouse gas emissions generated by a product during its entire life cycle, from raw material acquisition to final disposal, adjusted for global warming potential; X: represents the cumulative emission of a certain greenhouse gas based on functional unit F without considering the recycling of scrap steel; LCI EOL (Life cycle inventory of scrap steel recycling): measures the contribution of scrap steel recycling and reuse in reducing carbon emissions, which is deducted from total emissions; C i (Global Warming Potential): Each greenhouse gas has a different global warming potential depending on its contribution to the Earth's greenhouse effect.

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