Life cycle carbon footprint-based low-carbon steel iron product design method and system

Abstract

The invention provides a low-carbon steel iron product design method and system based on a life cycle carbon footprint. The low-carbon steel iron product design method comprises the steps that the system boundary of the full life cycle carbon footprint of a product is determined; collecting activity level data of each process in the system boundary and performing standardization processing; identifying an emission source according to the activity level data and acquiring an emission coefficient; calculating the carbon footprint of each process based on the standardized data and the emission coefficient; performing attribution and analysis on procedures and intermediate product carbon emission; and combining the carbon reduction target and the emission coefficient to optimize production processes and materials, and generating and evaluating an optimization scheme to determine a final scheme. According to the invention, the technical problems of insufficient carbon emission accounting precision, unclear emission attribution and lack of operability of emission reduction measures in the iron and steel industry in the prior art are solved.

Description

Technical Field

[0001] This invention relates to the fields of structural steel production and life cycle assessment, specifically to a method and system for designing low-carbon steel products based on life cycle carbon footprint. Background Technology

[0002] Currently, the steel industry generally employs carbon emission accounting and energy statistics methods for carbon emission management, estimating total carbon emissions by statistically analyzing energy consumption and emission factors. While these methods can reflect the overall emission level of an enterprise to some extent, they have significant technical limitations. First, most existing methods focus on calculating the overall emissions of the enterprise, lacking the decomposition and structured traceability of emissions by production process and material, making it impossible to identify specific high-emission links and material sources. Second, traditional accounting methods often rely on a single energy consumption or emission statistical caliber, making it difficult to standardize multi-source data, resulting in inconsistent emission data calibers and insufficient calculation accuracy. Third, existing emission accounting is disconnected from emission reduction measures, lacking operable production chain optimization strategies, and failing to form a closed-loop mechanism from emission identification to emission reduction decision-making.

[0003] On the other hand, Life Cycle Carbon Footprint (LCCF) analysis has gradually become the mainstream carbon accounting method internationally due to its ability to systematically quantify and decompose carbon emissions throughout a product's entire life cycle. However, in traditional LCCF applications, most studies still focus on the accounting and assessment of emissions results. For complex industrial processes (especially systems like steel production with multiple processes, energy consumption, and material inputs), there is a lack of attribution mechanisms and process optimization methods based on life cycle carbon emission structures. Particularly in the steel production chain, a large number of intermediate products (such as sintered ore, molten iron, and steel billets) are transferred between different processes, making it easy for emissions to be double-counted or ambiguously attributed, thus affecting the accuracy and decision-making reliability of the accounting results.

[0004] Furthermore, the industry currently lacks a systematic approach that organically integrates lifecycle carbon footprint accounting, emission attribution analysis, and carbon reduction pathway design. On the one hand, while companies can understand their total emissions through carbon inventory, they cannot effectively identify "who caused the emissions and at which stage they emitted the most." On the other hand, adjustments to processes and materials lack scientific quantitative basis, and emission reduction measures often rely on experience and subjective judgment, lacking dynamic evaluation and feedback mechanisms, making it difficult to form a sustainable carbon reduction design model.

[0005] Therefore, there is an urgent need for a technical approach that can accurately calculate carbon emissions and structurally attribute emission sources throughout the entire product lifecycle, and link it with process and material optimization strategies, thereby providing support for the steel industry to design a scientific emission reduction path.

[0006] Chinese patent CN202311778806.9 discloses a method for calculating the carbon footprint of structural steel products based on life cycle assessment. This method employs a life cycle assessment approach, defining assessment objectives, functional units, and system boundaries. It uses process inventory analysis to compile and quantify the environmental impact factors of structural steel throughout its life cycle, employing 22 indicators such as global warming and ozone formation for quantitative description. Based on a characteristic model, it scores the environmental impact types, establishes a life cycle inventory analysis model, classifies the environmental impact type parameters, and achieves environmental performance evaluation of structural steel products. This application uses a carbon footprint tracing method to optimize materials, energy, and processes; the two methods differ significantly in their technical approaches. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the purpose of this invention is to provide a method and system for designing low-carbon steel products based on lifecycle carbon footprint.

[0008] According to one aspect of the present invention, a method for designing low-carbon steel products based on life-cycle carbon footprint is provided, comprising: Step 1: determining the system boundary of the product's life-cycle carbon footprint; Step 2: collecting activity level data of each process within the system boundary and standardizing the activity level data; Step 3: identifying each emission source based on the activity level data and obtaining the emission coefficient of each emission source; Step 4: calculating the carbon footprint of each process based on the standardized activity level data and emission coefficients; Step 5: attributing and analyzing the carbon emissions of each process and intermediate products based on the carbon footprint of each process; Step 6: optimizing the product's production processes and materials based on the attribution and analysis results of Step 5 and the emission coefficients of each emission source in Step 3, combined with carbon reduction targets, to generate an optimization scheme; Step 7: evaluating the optimization scheme and determining the optimization scheme based on the evaluation results.

[0009] Preferably, the system boundaries in step one include raw material mining, production, and delivery.

[0010] Preferably, in step two, the activity level data of each process within the accounting scope is collected, and the activity level data is standardized, including: collecting the activity level data of each process according to the system boundary determined in step one, wherein the activity level data includes: the amount of raw materials and auxiliary materials used, the amount of energy consumed, the mode of transportation, the transportation distance, and the waste discharge; By using the material balance method, the rationality of the collected activity level data is verified based on the input-output relationship, and then the activity level data is converted into a baseline flow.

[0011] Preferably, in step three, identifying each emission source and obtaining the emission coefficient of each emission source includes: Based on the activity level data collected in step two, emission sources in the production process are identified. These sources include direct and indirect emission sources. Direct emission sources include stationary combustion, mobile combustion, chemical reaction processes, and waste treatment. Indirect emission sources include electricity, heat, transportation, and upstream purchased materials. Emission coefficients are obtained for each emission source. The direct emission coefficient reflects the direct emission level per unit of activity, while the indirect emission coefficient reflects the emission level of upstream processes. The emission coefficients are obtained by converting different greenhouse gases into carbon dioxide equivalents based on their global warming potential, thus quantifying greenhouse gas emissions uniformly.

[0012] Preferably, in step four, the carbon footprint of each process is calculated based on standardized activity level data and emission factors, including: The production process of a product is broken down into multiple process units, the material flow and energy flow of each process unit are clarified, the transfer relationship of intermediate products between process units is identified, a production flow chart is generated, and the input and output relationship between the preceding and following process units is kept consistent, forming a complete production chain model. Based on the production chain model, the carbon footprint of each process unit is calculated by calling the activity level data collected in step two and the emission coefficients determined in step three.

[0013] Preferably, the carbon footprint is calculated according to the following formula;

[0014] in, The product's carbon footprint or partial carbon footprint is expressed in kg CO2e / functional unit or kg CO2e / declared unit, reflecting the total greenhouse gas emissions from the entire process of raw material acquisition, transportation, production to delivery. Activity level data refers to the data at the activity level within the system boundary, representing the first functional unit or declaration unit. Data related to greenhouse gas emissions and removal for various activities are determined by the unit based on the specific emission source; For the first Greenhouse gases corresponding to various activities The emission coefficients are matched with GHG activity data in units; Greenhouse gases The GWP value shall be determined in accordance with the provisions of the standard.

[0015] Preferably, in step five, based on the carbon footprint of each process, the carbon emissions of each process and intermediate products are attributed and analyzed, including: Based on the production chain model and the carbon footprint of each process unit, the carbon emissions generated in each process unit are traced back to the initial raw material and energy sources in the order of the production chain, eliminating the duplicate inclusion of emissions between intermediate products. The carbon emissions involved in the entire production process of the product are summarized according to the source of materials. Based on the carbon footprint of each process unit, the carbon emissions corresponding to different materials or energy and their proportion to the total carbon footprint of the product are calculated. The carbon emissions involved in the entire production process are summarized by process dimension to obtain the carbon emissions of each process and its proportion.

[0016] Preferably, in step six, the optimization scheme includes: Based on the results of the attribution and analysis in step five, materials and energy sources with high emission ratios are replaced. For processes with high emissions, the carbon footprint levels of different production processes are compared to select those with lower carbon emissions, and the production chain structure and activity level data are adjusted accordingly.

[0017] Preferably, the optimization scheme is evaluated, and the optimization scheme is determined based on the evaluation results, including: According to the optimization plan, calculate the carbon footprint using the formula in step four, and compare it with the baseline results before optimization. If the carbon reduction target is achieved, the optimization plan is determined; if the target is not achieved, further adjust the material structure or process path, and repeat steps six and seven until the preset carbon emission reduction target is achieved.

[0018] According to another aspect of the present invention, a low-carbon steel product design system based on life cycle carbon footprint is provided, comprising: Module M1: Defines the system boundary of the product's carbon footprint throughout its entire lifecycle; Module M2: Collects activity level data of each process within the system boundary and performs standardization processing on the activity level data; Module M3: Based on activity level data, identify each emission source and obtain the emission coefficient of each emission source; Module M4: Calculates the carbon footprint of each process based on standardized activity level data and emission factors; Module M5: Based on the carbon footprint of each process, attribute and analyze the carbon emissions of each process and intermediate products; Module M6: Based on the results of the attribution and analysis in step five, and the emission coefficients of each emission source in module M3, combined with the carbon reduction target, the production process and materials of the product are optimized to generate an optimization plan; Module M7: Evaluates the optimization scheme and determines the optimization scheme based on the evaluation results.

[0019] Compared with the prior art, the present invention has the following beneficial effects: (1) By combining life cycle carbon footprint calculation, emission attribution and dynamic optimization design, this invention breaks through the limitation of existing technologies that can only perform static emission evaluation, and realizes the technological leap from "emission measurement" to "emission reduction design".

[0020] (2) This invention not only improves the accuracy of carbon footprint accounting, but also establishes a carbon emission attribution mechanism based on process units and forms a closed-loop optimization path, which can quickly identify high-emission materials and process units, support enterprises in formulating precise carbon reduction measures, and has significant engineering application value and promotion potential. Attached Figure Description

[0021] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a flowchart of a low-carbon steel product design method based on life cycle carbon footprint. Detailed Implementation

[0022] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0023] For ease of understanding, the terms or concepts involved in this application are explained below: (1) Life Cycle Carbon Footprint (LCCF) The life cycle carbon footprint refers to the total amount of greenhouse gases emitted directly or indirectly by a product throughout its entire life cycle (from raw material acquisition, processing, transportation, production, use to disposal, etc.), and is expressed as carbon dioxide equivalent (CO2e). This invention adopts a "cradle to gate" boundary, that is, the calculation scope covers raw material mining, transportation, production and delivery, but does not include the use and disposal stages.

[0024] (2) System Boundary The system boundary refers to the spatial and temporal range determined during carbon footprint accounting, used to clarify the calculation object and process. The system boundary of this invention includes the raw material mining stage, the product manufacturing stage, and the factory delivery stage, ensuring the integrity and consistency of the calculation process.

[0025] (3) Process Unit A process unit refers to the smallest functional unit of the production process used for emission accounting in carbon footprint calculation. It corresponds to an independent technical step or functional module in the steel production process, such as sintering, blast furnace ironmaking, converter steelmaking, continuous casting and rolling, etc. This invention uses the process unit as the basis for carbon emission calculation and attribution.

[0026] (4) Production Stage The production stage refers to a production phase consisting of multiple process units, such as the raw material preparation stage, ironmaking stage, steelmaking stage, and rolling stage. In this invention, the production stage is used for the classification and summary analysis of emission results, while the specific emission calculation is completed at the process unit level.

[0027] (5) Intermediate products: Intermediate products refer to semi-finished products or intermediate materials that are produced by upstream process units and input into downstream process units during the product manufacturing process, such as sintered ore, molten iron, and steel billets. In the attribution analysis, this invention traces back and deducts the carbon emissions of intermediate products to avoid double counting.

[0028] (6) Activity Level Data (AD) Activity level data refers to quantitative data used to describe the scale of carbon emission activities during the life cycle carbon emission accounting process. The activity level data in this invention includes the amount of raw materials and auxiliary materials used, energy consumption, transportation methods and distances, waste emissions, etc., which are the core input parameters for carbon footprint calculation.

[0029] (7) Material Balance Method The material balance method refers to a method of verifying the rationality and completeness of data by comparing the input and output of materials within the system. In this invention, the material balance method is used to verify input and output after the activity level data collection is completed, so as to ensure data closure and logical consistency.

[0030] (8) Baseline Flow: Baseline flow refers to the data format after unifying and standardizing activity level data from different sources, units, and calibers, so that it has a unified measurement basis. This process helps to improve the comparability and accuracy of carbon emission calculations.

[0031] (9) Emission Sources Emission sources refer to the specific sources that cause greenhouse gas emissions during the product manufacturing process. In this invention, emission sources are divided into direct emission sources and indirect emission sources. Direct emission sources include stationary combustion, mobile combustion, chemical reaction processes, and waste treatment; indirect emission sources include electricity, heat, transportation, and upstream purchased materials.

[0032] (10) Emission Factor (EF) The emission factor refers to the amount of greenhouse gas emissions per unit of activity level. It is an intensity parameter that converts activity level data into carbon emissions. The emission factor can be obtained from national or industry standard databases or determined based on measured data.

[0033] (11) Global Warming Potential (GWP) Global warming potential refers to the warming effect of greenhouse gases relative to carbon dioxide. Through GWP, different greenhouse gases (such as CO2, CH4, N2O) can be converted into CO2 equivalents, so as to achieve a unified measurement of emission results.

[0034] (12) Carbon footprint calculation formula The carbon footprint calculation formula is the core calculation tool of this invention. It is used to combine activity level data, emission factors and GWP to calculate the greenhouse gas emissions of each process unit and the entire product life cycle.

[0035] (13) Carbon emission attribution analysis. Carbon emission attribution analysis refers to the process of tracing carbon emissions back from intermediate products to source materials and energy, and decomposing and aggregating them according to material and process unit dimensions. This process can identify the main sources of carbon emissions, avoid double counting, and improve the accuracy of accounting.

[0036] (14) Carbon emission deduction Carbon emission deduction refers to removing the emissions of intermediate products from the carbon emissions of downstream processes during the attribution analysis process, so as to ensure that each part of the emissions is only calculated once and to avoid double counting.

[0037] (15) Carbon Emission Optimization Carbon emission optimization refers to the process of making targeted adjustments to high-emission materials and high-emission processes based on the results of attribution analysis. The optimization of this invention includes two aspects: material structure optimization and process path optimization, which are used to achieve the carbon reduction target of the product production process.

[0038] (16) Process route optimization Process route optimization refers to the technical means of reducing emissions by comparing the carbon emission levels of different production process routes, selecting the process route with lower carbon emissions, and adjusting the production chain structure and activity level data.

[0039] (17) Evaluation of Optimization Scheme: Evaluation of optimization scheme refers to the process of re-substituting the optimized material structure and process parameters into the carbon footprint calculation model, verifying the optimization effect, and comparing it with the benchmark scheme. If the target is met, the scheme is determined; otherwise, adjustments are made to form a closed-loop optimization mechanism.

[0040] (18) Closed-loop optimization mechanism. The closed-loop optimization mechanism refers to the continuous reduction of carbon emissions in the production process through an iterative process of "calculation-attribution-optimization-recalculation". This invention introduces a closed-loop mechanism to enable the carbon reduction design to have dynamic adjustment capabilities.

[0041] (19) High-emission materials: High-emission materials refer to raw materials or energy sources that account for a large proportion of carbon emissions throughout the product's life cycle, such as coal, coke, and electricity. This invention identifies high-emission materials through attribution analysis, providing a basis for material substitution and emission reduction measures.

[0042] (20) High-emission process units: High-emission process units refer to production processes with a high proportion of carbon emissions, such as sintering and blast furnace ironmaking. This invention identifies key emission reduction processes by calculating and analyzing the emission proportion of process units, providing direction for process path optimization.

[0043] The following is a detailed explanation of each step: In step one, the system boundary of the product's carbon footprint throughout its entire lifecycle is determined. The system boundary is a prerequisite for carbon footprint accounting, clearly defining the scope and objects of carbon emission calculation. Preferably, the system boundary of this invention includes three stages: raw material mining, production, and factory exit, adopting a "cradle-to-gate" accounting model. The raw material mining stage includes the acquisition and initial transportation of resources such as iron ore, coal, and coke; the production stage includes typical steel production processes such as sintering, blast furnace ironmaking, converter steelmaking, and continuous casting and rolling; and the factory exit stage includes the transportation and loading / unloading of finished products. By defining the system boundary, the uniformity and integrity of the carbon footprint accounting scope can be ensured, providing clear boundary conditions for subsequent calculations and optimizations.

[0044] In step two, activity level data for each process within the system boundary is collected and standardized. Activity level data is the foundation for carbon emission calculations, reflecting the actual production levels of each process within its lifecycle, including energy consumption, material input, and waste emissions. Preferably, the activity level data includes the usage of raw materials and auxiliary materials, energy consumption, transportation methods and distances, and waste emissions. After data collection, the material balance method is used to verify the rationality of the input-output relationship, ensuring the data's authenticity and closure. Subsequently, the verified data is converted into a baseline stream, unifying the units of measurement and statistical standards to standardize the activity level data. This step significantly improves the accuracy and traceability of subsequent carbon emission calculations.

[0045] In step three, emission sources are identified based on activity level data, and emission coefficients for each source are obtained. These emission sources include direct and indirect sources. Direct sources include stationary combustion, mobile combustion, chemical reaction processes, and waste treatment; indirect sources include electricity, heat, transportation, and upstream purchased materials. For different types of emission sources, corresponding emission coefficients are assigned. These emission coefficients represent the greenhouse gas emission intensity per unit of activity. Direct emission coefficients reflect the carbon intensity emitted at the factory site, while indirect emission coefficients reflect the implicit emissions from upstream processes or purchased energy. This invention preferably determines emission coefficients based on national standards, industry databases, or enterprise-measured data. For multiple greenhouse gas emissions, they are uniformly converted into carbon dioxide equivalents (kg CO2e) using the Global Warming Potential (GWP), achieving unified quantification of multiple greenhouse gas emissions.

[0046] In step four, the carbon footprint of each process is calculated based on standardized activity level data and emission coefficients. First, the steel production process is broken down into multiple process units, such as sintering, blast furnace ironmaking, converter steelmaking, and continuous casting and rolling. The material and energy flows of each process unit are clearly defined, the transfer relationships of intermediate products between process units are identified, and a production flow diagram is generated to ensure consistency in the input-output relationships between preceding and subsequent process units, forming a complete production chain model. Then, based on this model, the activity level data collected in step two and the emission coefficients determined in step three are used to calculate the carbon footprint of each process unit using the carbon footprint calculation formula.

[0047] The carbon footprint calculation formula is as follows:

[0048] in, The product's carbon footprint or partial carbon footprint is expressed in kg CO2e / functional unit or kg CO2e / declared unit, reflecting the total greenhouse gas emissions from the entire process of raw material acquisition, transportation, production to delivery. Activity level data refers to the data at the activity level within the system boundary, representing the first functional unit or declaration unit. Data related to greenhouse gas emissions and removal for various activities are determined by the unit based on the specific emission source; For the first Greenhouse gases corresponding to various activities The emission coefficients are matched with GHG activity data in units; Greenhouse gases The GWP value shall be determined in accordance with the provisions of the standard.

[0049] In step five, carbon emissions from each process and intermediate product are attributed and analyzed based on the carbon footprint of each process. Since emissions from intermediate products may be repeatedly counted across different processes during the calculations in step four, this step uses a backtracking and offsetting approach to achieve unique carbon emission attribution. Specifically, based on the production chain model and the carbon footprint of each process unit, carbon emissions generated in each process unit are traced back step-by-step to the initial raw material and energy sources in the production chain sequence. Emissions from intermediate products (such as sintered ore and molten iron) that are repeatedly counted in downstream processes are eliminated to remove duplicate statistics. Subsequently, carbon emissions involved in the entire production process are summarized according to material sources. Based on the carbon footprint of each process unit, the carbon emissions corresponding to different materials or energy sources and their proportion of the total product carbon footprint are calculated, thereby identifying high-emission materials. Then, carbon emissions during the product production process are summarized by process dimension to obtain the net carbon emissions of each process unit and their proportion, identifying high-emission process units. Through the above attribution analysis steps, a two-dimensional carbon emission structure of materials and processes is formed, providing a precise decision-making basis for subsequent carbon reduction optimization.

[0050] In step six, based on the attribution and analysis results of step five and the emission coefficients of each emission source in step three, and in conjunction with carbon reduction targets, the production processes and materials of the product are optimized to generate an optimized plan. The optimized plan includes both material and energy structure optimization and process route optimization. For materials or energy sources with high emission proportions, the intensity of carbon emissions at the source is reduced by replacing high-carbon emission energy sources (e.g., replacing purchased electricity with green electricity, or coke with low-carbon coal) and adjusting the proportion structure. For processes with high emission proportions, the carbon footprint levels of different production processes are compared to select production routes with lower carbon emissions, such as shifting from traditional blast furnace processes to electric furnace or hydrogen-based vertical shaft furnace processes. The production chain structure and activity level data are then adjusted based on the new process to form an optimized production plan.

[0051] In step seven, the optimized scheme is evaluated, and the final optimized scheme is determined based on the evaluation results. The evaluation process includes: substituting the activity level data of the optimized scheme back into the carbon footprint calculation formula of step four to obtain the optimized carbon emission results; comparing and analyzing this result with the baseline emission results; if the optimized scheme achieves the preset carbon reduction target, then the scheme is determined as the final production design scheme; if it does not achieve the target, then further adjusting the material structure or process path, repeating steps six and seven until the preset carbon emission reduction target is achieved. Through this feedback-verification-re-optimization process, the present invention achieves dynamic synergistic control between production process and carbon emissions.

[0052] In summary, this invention achieves low-carbon design for steel products from production to delivery through lifecycle carbon footprint calculation, emission attribution analysis, and optimized feedback mechanisms. Compared with traditional static carbon emission accounting methods, this invention effectively avoids the problem of double-counting carbon emissions from intermediate products, accurately identifies the main sources of carbon emissions, and achieves systematic carbon reduction in the production process through targeted optimization of high-emission materials and processes. This invention has the technical advantages of high calculation accuracy, clear path, and strong operability, and is applicable to carbon emission reduction management and the construction of green manufacturing systems in the steel industry.

[0053] Those skilled in the art will understand that, besides implementing the system and its various devices, modules, and units provided by this invention in the form of purely computer-readable program code, the same functions can be achieved entirely through logical programming of the method steps, making the system and its various devices, modules, and units of this invention function in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers. Therefore, the system and its various devices, modules, and units provided by this invention can be considered as a hardware component, and the devices, modules, and units included therein for implementing various functions can also be considered as structures within the hardware component; alternatively, the devices, modules, and units for implementing various functions can be considered as both software modules implementing the method and structures within the hardware component.

[0054] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A low-carbon steel product design method based on life cycle carbon footprint, characterized in that, include: Step 1: Determine the system boundaries of the product's carbon footprint throughout its entire lifecycle; Step 2: Collect activity level data for each process within the system boundary, and standardize the activity level data; Step 3: Based on the activity level data, identify each emission source and obtain the emission coefficient for each emission source; Step 4: Calculate the carbon footprint of each process based on the standardized activity level data and emission factors; Step 5: Based on the carbon footprint of each process, attribute and analyze the carbon emissions of each process and intermediate products; Step Six: Based on the attribution and analysis results of Step Five, and the emission coefficients of each emission source in Step Three, combined with the carbon reduction target, optimize the product's production process and materials to generate an optimization plan; Step 7: Evaluate the optimization scheme and determine the optimal scheme based on the evaluation results.

2. The method according to claim 1, characterized in that, The system boundary in step one includes raw material mining, production, and delivery.

3. The method according to claim 2, characterized in that, In step two, activity level data of each process within the accounting scope are collected, and the activity level data is standardized, including: collecting activity level data of each process according to the system boundary determined in step one, wherein the activity level data includes: the amount of raw materials and auxiliary materials used, the amount of energy consumed, the mode of transportation, the transportation distance, and the waste discharge. By using the material balance method, the rationality of the collected activity level data is verified based on the input-output relationship, and then the activity level data is converted into a baseline flow.

4. The method according to claim 1, characterized in that, In step three, each emission source is identified, and the emission coefficient of each emission source is obtained, including: Based on the activity level data collected in step two, emission sources in the production process are identified. These sources include direct and indirect emission sources. Direct emission sources include stationary combustion, mobile combustion, chemical reaction processes, and waste treatment. Indirect emission sources include electricity, heat, transportation, and upstream purchased materials. Emission coefficients are obtained for each emission source. The direct emission coefficient reflects the direct emission level per unit of activity, while the indirect emission coefficient reflects the emission level of upstream processes. The emission coefficients are obtained by converting different greenhouse gases into carbon dioxide equivalents based on their global warming potential, thus quantifying greenhouse gas emissions uniformly.

5. The method according to claim 1, characterized in that, In step four, the carbon footprint of each process is calculated based on the standardized activity level data and emission coefficients, including: The production process of a product is broken down into multiple process units, the material flow and energy flow of each process unit are clarified, the transfer relationship of intermediate products between process units is identified, a production flow chart is generated, and the input and output relationship between the preceding and following process units is kept consistent, forming a complete production chain model. Based on the production chain model, the carbon footprint of each process unit is calculated by calling the activity level data collected in step two and the emission coefficients determined in step three.

6. The method according to claim 5, characterized in that, Carbon footprint is calculated using the following formula; in, The product's carbon footprint or partial carbon footprint is expressed in kg CO2e / functional unit or kg CO2e / declared unit, reflecting the total greenhouse gas emissions from the entire process of raw material acquisition, transportation, production to delivery. Activity level data refers to the data at the activity level within the system boundary, representing the first functional unit or declaration unit. Data related to greenhouse gas emissions and removal for various activities are determined by the unit based on the specific emission source; For the first Greenhouse gases corresponding to various activities The emission coefficients are matched with GHG activity data in units; Greenhouse gases The GWP value shall be determined in accordance with the provisions of the standard.

7. The method according to claim 5 or 6, characterized in that, In step five, based on the carbon footprint of each process, the carbon emissions of each process and intermediate products are attributed and analyzed, including: Based on the production chain model and the carbon footprint of each process unit, the carbon emissions generated in each process unit are traced back to the initial raw material and energy sources in the order of the production chain, eliminating the duplicate inclusion of emissions between intermediate products. The carbon emissions involved in the entire production process of the product are summarized according to the source of materials. Based on the carbon footprint of each process unit, the carbon emissions corresponding to different materials or energy and their proportion to the total carbon footprint of the product are calculated. The carbon emissions involved in the entire production process are summarized by process dimension to obtain the carbon emissions of each process and its proportion.

8. The method according to claim 7, characterized in that, In step six, the optimization scheme includes: Based on the results of the attribution and analysis in step five, materials and energy sources with high emission ratios are replaced. For processes with high emissions, the carbon footprint levels of different production processes are compared to select those with lower carbon emissions, and the production chain structure and activity level data are adjusted accordingly.

9. The method according to claim 8, characterized in that, In step seven, the optimization scheme is evaluated, and the optimization scheme is determined based on the evaluation results, including: According to the optimization plan, calculate the carbon footprint using the formula in step four, and compare it with the baseline results before optimization. If the carbon reduction target is achieved, the optimization plan is determined; if the target is not achieved, further adjust the material structure or process path, and repeat steps six and seven until the preset carbon emission reduction target is achieved.

10. A low-carbon steel product design system based on life cycle carbon footprint, characterized in that, include: Module M1: Defines the system boundary of the product's carbon footprint throughout its entire lifecycle; Module M2: Collects activity level data of each process within the system boundary and performs standardization processing on the activity level data; Module M3: Based on activity level data, identify each emission source and obtain the emission coefficient of each emission source; Module M4: Calculates the carbon footprint of each process based on standardized activity level data and emission factors; Module M5: Based on the carbon footprint of each process, attribute and analyze the carbon emissions of each process and intermediate products; Module M6: Based on the results of the attribution and analysis in step five, and the emission coefficients of each emission source in module M3, combined with the carbon reduction target, the production process and materials of the product are optimized to generate an optimization plan; Module M7: Evaluates the optimization scheme and determines the optimization scheme based on the evaluation results.

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