Long-term economic decarburization path comprehensive evaluation method and system for iron and steel industry

Abstract

The invention provides a long-term economic decarburization path comprehensive evaluation method and system for the iron and steel industry, and the method comprises the following steps: 1) analyzing the life cycle CO2 emission of the iron and steel industry, and calculating to obtain the direct and indirect CO2 emission and total CO2 emission of a unit product of each process of a long-flow route and a short-flow route; (2) the decarburization technology of the iron and steel industry is evaluated from a plurality of standards by taking the economic benefit, the environmental benefit and the technical maturity as three evaluation standards; and 3) determining an optimal technology development path by combining the carbon emission result calculated in the step 1) and the evaluation result of each decarburization technology in the step 2), and evaluating the influence of the combination of different decarburization technologies on the carbon emission and economic benefits of the iron and steel industry according to the optimal technology development path. The method provides a valuable insight to integrate energy, resources, carbon emissions and economic considerations, and can be used for evaluation to obtain an effective carbon emission reduction path.

Description

Technical Field

[0001] The present invention belongs to the technical field of decarbonization path evaluation, and relates to a comprehensive evaluation method and system for the long-term economic decarbonization path of the steel industry. Background Art

[0002] Currently, the steel industry accounts for a significant share of global carbon emissions, and the choice of its decarbonization path is directly related to the global response to climate change. The steel industry has proposed a number of emission reduction technologies applicable to different processes to improve energy efficiency, reduce emissions and promote the green transformation of the industry, including the promotion of advanced technologies, optimization of energy systems and the use of waste heat and waste pressure. However, previous studies have mainly measured the carbon reduction potential of a single technology, without paying enough attention to the matching and combination of various technologies in the entire industry, as well as the synergy and trade-off between carbon reduction goals and cost goals. In addition, the lack of strategic research on the configuration of different technology combinations makes it difficult to predict the specific level of carbon emission intensity and cost investment in the future steel industry.

[0003] In the future, the internal production structure, energy consumption structure and external market environment of the steel industry will be subject to great uncertainty. It is very difficult to evaluate the applicability and development trend of different technologies over such a long time scale, and it is also necessary to select the most appropriate technology development path based on the dynamic characteristics of technology changing over time.

[0004] The existing decarbonization path selection strategy still has the following defects:

[0005] Insufficient economic benefit assessment: Although low-carbon technologies continue to emerge in the industrial sector, especially in the steel industry, there is a lack of a systematic method to evaluate the economic benefits of these technologies at different carbon price levels, making it difficult for decision makers to make scientific technology choices and investment decisions.

[0006] Lack of optimal development path: There is a lack of a clear framework to guide how to deploy the optimal technology development path based on different goal orientations (such as carbon emission reduction priority or cost control priority).

[0007] Uncertainty in emission reduction effects and cost control: How to ensure accurate prediction of specific emission reduction effects and cost control after the implementation of various technologies under the optimal technology development path.

[0008] Insufficient assessment of the impact of external factors: The transformation of energy structure, technological progress and environmental market changes have a huge impact on the steel industry. How to comprehensively evaluate the specific impact of these factors on technology deployment to achieve low-carbon and low-cost development of the steel industry is an urgent issue.

[0009] Therefore, developing a method and system that can comprehensively evaluate long-term economic decarbonization paths is crucial to achieving sustainable development of the steel industry. Summary of the invention

[0010] The present invention aims to evaluate the performance of low-carbon technologies in terms of carbon emission cost, penetration, payback time, service life and cost-effectiveness ratio through a comprehensive evaluation method for the long-term economic decarbonization path of the steel industry, and optimize the long-term decarbonization strategy. This method is particularly suitable for long-process and short-process technology routes in the steel production process to achieve economically feasible carbon emission reduction solutions. The model can identify the optimal dynamic decarbonization development path by 2035 to minimize costs and carbon emissions, providing a scientific decision support tool for the steel industry.

[0011] The technical solution adopted by the present invention is:

[0012] The present invention systematically conducts a multi-criteria evaluation of individual decarbonization technologies and optimizes the technology development path of the steel industry, focusing on technology, CO2 emission reduction and economic potential. The method includes three steps: life cycle CO2 emission analysis, multi-criteria technology evaluation and multi-technology dynamic optimization. These steps are implemented based on life cycle assessment (LCA), techno-economic assessment (TEA), conservative supply curve and multi-objective dynamic optimization principles. The inventive method studies two main steel industry manufacturing routes, namely the long process route and the short process route. The intermediate products of each route are used as inputs for subsequent processes, and the production steps are connected by the steel ratio coefficient (the number of process products required per unit of crude steel). The long process route involves coke production, sintering, blast furnace ironmaking, converter steelmaking and steel processing (including hot rolling, cold rolling, plating and coating). The short process route is entirely based on scrap steel, including electric furnace steelmaking and steel processing (including hot rolling, cold rolling, plating and coating).

[0013] A comprehensive evaluation method for the long-term economic decarbonization path of the steel industry includes the following steps:

[0014] 1) Analyze the life cycle CO2 emissions of the steel industry and calculate the direct and indirect CO2 emissions per unit product and the total CO2 emissions for each process of the long and short process routes;

[0015] 2) Incorporate economic benefits, environmental benefits and technological maturity as three evaluation criteria, and evaluate the decarbonization technology of the steel industry from multiple criteria;

[0016] 3) Combining the carbon emission results calculated in step 1) and the evaluation results of each decarbonization technology in step 2), the impact of the combination of different decarbonization technologies on the carbon emissions and economic benefits of the steel industry is evaluated according to the optimal technology development path.

[0017] In the above technical solution, further, in the step 1), direct CO2 emissions include emissions from fossil fuel combustion and emissions from the steel production process, and emissions from the steel production process include emissions from thermal decomposition of iron ore flux and emissions generated during the decarbonization of steel; indirect CO2 emissions come from fossil fuels, iron ore flux, electrodes and upstream activity emissions, and upstream activity emissions cover the CO2 emission process from mining to ore dressing, transportation and electricity consumption.

[0018] Furthermore, in step 2), the economic benefit is quantified by carbon reduction cost and benefit-cost ratio, the environmental benefit is quantified by payback period, and the technical maturity is quantified by service life and penetration rate.

[0019] Furthermore, in the step 3), the method for determining the optimal technological development path is: based on the carbon emission results obtained in step 1) and the evaluation results of each decarbonization technology in step 2), as well as the production structure, energy supply model and output of the steel industry, under the constraints of steel demand, energy consumption control and technological development, determine the optimal dynamic changes in the penetration rates of various technologies, and determine the optimal technological development path based on the optimal dynamic changes in the technology penetration rates.

[0020] The present invention also provides a comprehensive evaluation system for the long-term economic decarbonization path of the steel industry, which is used to implement the above method, specifically comprising:

[0021] Lifecycle CO2 emission analysis module: used to analyze the lifecycle CO2 emissions of the steel industry, and calculate the direct and indirect CO2 emissions per unit product and the total CO2 emissions for each process of the long and short process routes;

[0022] Among them, the CO2 emissions of each route are calculated by considering direct emissions and indirect emissions related to energy. Direct emissions include emissions from the combustion of fossil fuels (such as coking coal, anthracite, diesel and natural gas) and emissions from the steel production process. Emissions from the steel production process include emissions from the thermal decomposition of iron ore fluxes (such as limestone and dolomite) (CO2 is released when calcium carbonate and magnesium carbonate decompose at high temperatures) and emissions from the decarbonization process of steel (excess carbon and other impurities in blast furnace pig iron are oxidized into CO2 or removed with slag under the action of oxidants). Indirect emissions generally come from fossil fuels, iron ore fluxes, electrodes and upstream activity emissions. Upstream activity emissions cover CO2 emissions from mining to ore dressing, transportation and electricity consumption related processes:

[0023] Multi-criteria technology assessment module: used to include economic benefits, environmental benefits and technological maturity as three assessment criteria, and to assess the decarbonization technology of the steel industry from multiple criteria;

[0024] Economic benefits are quantified by carbon reduction costs and benefit-cost ratios, environmental benefits are reflected by payback periods, and technology maturity is measured by service life and penetration rates. These indicators are derived from a comprehensive analysis of each technology’s energy savings, decarbonization potential, investment and operating costs, service life, and penetration rates.

[0025] Multi-technology dynamic optimization module: used to determine the optimal technology development path by combining the carbon emission results obtained by the life cycle CO2 emission analysis module and the evaluation results of each decarbonization technology in the multi-standard technology evaluation module, and evaluate the impact of different decarbonization technology combinations on the carbon emissions and economic benefits of the steel industry based on the optimal technology development path. This module evaluates the trade-offs of various development strategies to achieve low-carbon and cost-effective progress by determining the optimal technology path to minimize carbon emissions and costs in the steel industry during the study period.

[0026] The beneficial effects of the present invention are:

[0027] The method and system can provide a comprehensive framework for the Chinese steel industry to evaluate and obtain effective carbon reduction paths, providing valuable insights into integrating energy, resources, carbon emissions and economic considerations. The method of the present invention can determine the optimal dynamic changes of various technology penetration rates under the constraints of steel demand, energy consumption control and technological development by considering the carbon emission results of the life cycle CO2 emission analysis module, the static evaluation results of the single technology of the multi-standard technology evaluation module, and the production structure, energy supply mode and steel industry output, and determine the optimal technology development path based on the optimal dynamic changes of technology penetration rates. Subsequently, the optimal technology development path can be used to evaluate the technology decarbonization potential, future industry CO2 emission intensity and future industry cost distribution. In order to cope with the complexity brought by numerous choices, multi-objective optimization can be used to generate a Pareto frontier that highlights the necessary compromises between different goals and technology choices. The main tool for this optimization process is genetic algorithm (GA). In the present invention, GA is used to minimize the objective function of CO2 emissions and costs and balance CO2 emissions and costs, aiming to simultaneously reduce the cumulative total cost and CO2 emissions from 2024 to 2035. Taking into account future policy preferences for the steel industry, especially preferences regarding CO2 emission control and cost reduction budgets, this approach adjusts the cumulative total costs and CO2 emissions by applying various weighting factors under different preference scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Flowchart of a comprehensive evaluation method for long-term economic decarbonization pathways in the steel industry. DETAILED DESCRIPTION

[0029] The invention provides a comprehensive evaluation method for a long-term economic decarbonization path for the steel industry, which is implemented by relying on a comprehensive evaluation system for a long-term economic decarbonization path for the steel industry.

[0030] In order to guide the steel industry towards a long-term sustainable future, the present invention develops a comprehensive evaluation system for the long-term economic decarbonization path of the steel industry to optimize the long-term carbon emission reduction strategy. The system includes three modules: a life cycle CO2 emission analysis module, a multi-standard technology evaluation module and a multi-technology dynamic optimization module. The life cycle CO2 emission analysis of the system analyzes the life cycle carbon emissions of direct and indirect CO2 in the long process route BF-BOF and the short process route EAF production path; then, the multi-standard technology evaluation module evaluates the decarbonization technology based on carbon reduction cost, penetration rate, payback period, service life and benefit-cost ratio, and evaluates the impact of carbon price fluctuations on technology investment and cost-effectiveness. Finally, the multi-technology dynamic optimization module uses the carbon emission results obtained by the life cycle CO2 emission analysis module and the evaluation results of each decarbonization technology in the multi-standard technology evaluation module, while considering the production structure, energy supply mode and steel industry output, etc., under the constraints of steel demand, energy consumption control and technological development, to determine the optimal dynamic changes of various technology penetration rates, and determine the optimal technology development path according to the optimal dynamic changes of technology penetration rates. According to the optimal technology development path, the impact of different decarbonization technology combinations on carbon emissions and economic benefits of the steel industry is evaluated, and costs and carbon emissions are minimized by focusing on CO2 emissions or cost preference scenarios. The optimal multi-technology development path to 2035 is determined, and the cumulative carbon reduction potential of each technology and the dynamic trends of CO2 emission intensity and cost in the steel industry are analyzed. Finally, the impact of changes in production paths, carbon prices and energy supply patterns on the optimal development path is examined, and a multi-technology planning strategy for achieving low-carbon and low-cost goals is obtained.

[0031] Life cycle CO2 emissions analysis module

[0032] It is used to analyze the life cycle CO2 emissions of the steel industry, and calculate the direct and indirect CO2 emissions per unit product and the total CO2 emissions of each process in the long process and short process routes. The calculation formulas for the long and short processes are the same, but the difference is that the long process has more carbon emission calculation items, and the calculation items that do not exist in the short process can be directly taken as 0. For example, the process related to the steel ratio coefficient of the blast furnace ironmaking and converter steelmaking processes in the long process path does not exist in the carbon emission short process, so this part is 0. The specific calculation formula is:

[0033]

[0034] in, and represents the direct and indirect CO2 emissions per unit product of process i in route m; and They represent the amount of fuel, flux, electrode and power consumed per unit product of process i in route m respectively; and are the direct CO2 emission factors of various fuels and fluxes respectively; the steel ratio coefficients of blast furnace ironmaking and converter steelmaking in the long process path are SR BF and SR BOF Indicates; C p and C r are the average carbon contents of pig iron and rolled steel, respectively; and They are the indirect CO2 emission factors of various fuels, fluxes and electrodes; the CO2 emission factor of electricity consumption is EF ele express; Represents the total CO2 emissions per unit product of process i in route m.

[0035] Multi-criteria Technology Assessment Module

[0036] In order to prioritize the decarbonization technologies for the steel industry from multiple criteria, key parameters reflecting economic benefits, environmental benefits and technological maturity are included. These multi-criteria assessments provide a basis for the prioritization of individual technologies and illustrate how low-carbon, low-cost goals affect the evolution mechanism of applicable decarbonization technologies. The evaluation items include payback period, benefit-cost ratio, carbon reduction cost and service life. The carbon reduction cost includes energy saving and CO2 emission reduction benefits, demonstrating the technical and economic efficiency of the evaluated technologies, and improving the traditional conservative supply curve method by incorporating energy and decarbonization benefits into the calculated cost of each decarbonization technology.

[0037]

[0038] Among them, ACC j and OM j Represent the annual investment and operating cost of technology j respectively; F j represents the capital investment in the life cycle of technology j; d represents the discount rate; L j represents the service life of technology j; CCR j ,PPSI j , and BCR j They represent the carbon reduction cost, static investment payback period and cost-effectiveness ratio of technology j, including energy saving and CO2 emission reduction benefits; and represents the energy saving and CO2 emission reduction per ton of crude steel by technology j; E E and represent the actual energy price and CO2 emission price respectively.

[0039] The quantification method of technology maturity is as follows: technology maturity is quantified by service life and penetration rate. The service life and penetration rate parameters are determined based on literature, the national key energy-saving and low-carbon technology promotion catalogue, and the operating experience of China's steel industry.

[0040] Multi-technique dynamic optimization module

[0041] The optimal technology development path is determined by combining the carbon emission results obtained from the life cycle CO2 emission analysis module and the evaluation results of each decarbonization technology in the multi-criteria technology evaluation module, and the impact of the combination of different decarbonization technologies on the carbon emissions and economic benefits of the steel industry is evaluated based on the optimal technology development path. When dealing with complex planning problems with many options, a multi-objective optimization method is used to generate a Pareto frontier that highlights the necessary trade-offs between decarbonization technology options under different objectives. The main optimization tool used is the genetic algorithm (GA), which is used to minimize an objective function that balances CO2 emissions and costs, with the goal of simultaneously reducing the total cumulative costs and CO2 emissions from 2024 to 2035. Taking into account the future policy tendencies of the steel industry, especially regarding CO2 emission control and cost reduction budgets, this method adjusts the total cumulative costs and CO2 emissions by applying various weight factors under different preference scenarios. Two development scenarios were examined: (1) CO2 emission control preference scenario (CEPS, the relative weight of CO2 emission is 0.9, the relative weight of cost is 0.1, w1=0.9 and w2=0.1); (2) cost control preference scenario (CPS, the relative weight of CO2 emission is 0.1, the relative weight of cost is 0.9, w1=0.1 and w2=0.9).

[0042] The objective function is defined as follows:

[0043]

[0044] w1+w2=1#(9)

[0045] Among them, w1 and w2 represent the relative weight factors assigned to CO2 emission and cost targets, respectively; represents the total cumulative CO2 emissions from the steel industry during the analysis period; and Respectively represent The maximum and minimum values ​​of cost represent the total cumulative cost of the steel industry during the analysis period; cost max and cost min Represent the maximum and minimum values ​​of the cost respectively. and cost to mitigate the differences caused by unit-related changes.

[0046] In order to calculate the total cumulative costs and CO2 emissions from 2024 to 2035, the formula takes into account the proportion of long and short process routes in the steel industry, the dynamic changing capabilities of various carbon reduction technologies during the study period, CO2 emission reductions, energy savings, and necessary capital and operating costs. After obtaining the total cumulative costs and CO2 emissions, the calculation process simultaneously tracks the trends in production volume, CO2 emissions and energy intensity, as well as fuel and CO2 emission costs in the steel industry. For the best technical path determined, the achievable results are detailed, such as annual carbon reduction potential, related energy demand, total CO2 emissions and total costs. The calculation of cost and related intermediate variables is as follows:

[0047]

[0048]

[0049] Among them, r m Indicates the proportion of long-process and short-process routes in the steel industry; andQ E represents the total CO2 emissions and total energy consumption of the steel industry in the time interval [0, T]; t is a time variable with one step per year; SR m,i represents the steel ratio coefficient of process i in route m; P t represents the crude steel production at time t; and represents the CO2 emission intensity and energy consumption intensity of process i of route m at time t and t-1 respectively; j represents the technology applicable to process i of route m; J j Represents the total number of available technologies; pr j,t and pr j,t-1 denote the penetration rate of technology j at time t and t-1, respectively; and They represent the equivalent CO2 emission intensity and energy consumption intensity of the steel industry at time t; S j,t Cap represents the capacity of technology j at time t; m,i,t N represents the production capacity of process i of route m at time t; j,t represents the capacity of technology j introduced at time t through investment; e j,t represents the aging rate of technology j at time t; represents the capacity of technology j that is eliminated at time t; L j represents the service life of technology j; represents the annual CO2 emission reduction potential of technology j; cost represents the total cost of the steel industry in the time interval [0, T], including the investment and operating costs of the applicable technology as well as the fuel and CO2 costs; ACC j,trepresents the annualized investment cost of technology j at time t; F j,t represents the investment cost of technology j at time t; OM j,t represents the operating cost of technology j at time t; and represent the real-time CO2 emissions and fuel prices at time t respectively.

[0050] The feasibility of the optimal solution is ensured by the following constraints. The supply and demand balance equation ensures that production capacity matches product demand. The energy-saving target constraint is in line with the national goal of achieving high-quality development of the steel industry through energy conservation and carbon reduction. This constraint requires compliance with the goal of reducing energy consumption per ton of steel. The technology development constraint, in which the diffusion process of technology is described using the Logistic (S) curve.

[0051] Cap m,i,t =P m,i,t =SR m,i ×P t #(twenty two)

[0052]

[0053] in, represents the decline rate of energy consumption intensity of the steel industry at time t; α j represents the initial growth rate of technology j, and j′ represents the technology of the same type as technology j and has a substitution effect.

[0054] The method of the present invention was used to evaluate the long process route and the short process route, and the results are as follows:

[0055] Based on the evaluation of 43 advanced decarbonization technologies for the long process route and 17 technologies for the short process route, most technologies have a benefit-cost ratio of more than 1, indicating economic feasibility, of which 74.4% of the long process technologies and 82.4% of the short process technologies meet this criterion. The carbon reduction cost range for long process technologies is -0.5 to 0.4 yuan / kg CO2, while the range for short process technologies is -0.3 to -0.02 yuan / kg CO2. Under medium and high carbon prices, the carbon reduction costs of most technologies are below the break-even threshold, with average costs of -0.048 yuan / Kg CO2 and -0.39 yuan / Kg CO2, respectively, and volatility indexes of 12.08 and 0.939, respectively. This shows that higher carbon prices can significantly reduce the overall CO2 emission reduction cost distribution of decarbonization technologies.

[0056] The optimal multi-technology development path is determined, and the impact of different preferences on carbon emission reduction needs and cost control is analyzed, covering the annual changes in technology penetration in the long and short process routes from 2024 to 2035. Technologies are classified according to their cumulative CO2 emission reduction potential: more than five million tons (advanced), less than five million tons (medium), and less than zero (conservative). The analysis of the optimal multi-technology path shows the dynamic changes in the industry's CO2 emission intensity and cost distribution. Compared with the long process, the short process shows a greater emission reduction potential. By 2030, the total equivalent CO2 emission intensity of the steel industry is reduced by 9.5% and 9% under the carbon emission control preference scenario and the cost control preference scenario compared to the current level. By 2035, the reduction is 13.78% and 14.36%, respectively. In economic terms, the total cost along the optimal path increases every year. The proportion of CO2 emission costs rises, while energy costs tend to decline. However, by 2035, energy costs still account for the highest proportion of total costs, exceeding CO2 emission costs.

[0057] The optimal multi-technology development path is affected by changes in production paths, carbon prices, and energy supply patterns. The lower share of short-process steel production reduces the carbon reduction potential of several technologies to zero, indicating less active demand for technology development. Changes in energy supply patterns, such as photovoltaic power compared to grid power, lead to lower CO2 emission reduction potential for 55.81% of BF-BOF technologies and 47.06% of short-process technologies. Continued reliance on coal power will increase the demand for decarbonization technologies, especially in the long-process technology route. Overall, the shift to low-carbon energy will reduce the reliance on adopting these technologies to meet future development needs.

[0058] The method and system can provide a comprehensive framework for the Chinese steel industry to evaluate and derive effective carbon reduction pathways, providing valuable insights into integrating energy, resources, carbon emissions and economic considerations.

Claims

1. A comprehensive evaluation method for the long-term economic decarbonization path of the steel industry, characterized in that: The following steps are involved: 1) Analyze the life cycle CO2 emissions of the steel industry and calculate the direct and indirect CO2 emissions per unit product and the total CO2 emissions for each process of the long and short process routes; 2) Incorporate economic benefits, environmental benefits and technological maturity as three evaluation criteria, and evaluate the decarbonization technology of the steel industry from multiple criteria; 3) Determine the optimal technology development path based on the carbon emission results calculated in step 1) and the evaluation results of each decarbonization technology in step 2), and evaluate the impact of the combination of different decarbonization technologies on the carbon emissions and economic benefits of the steel industry based on the optimal technology development path.

2. The comprehensive evaluation method for the long-term economic decarbonization path for the steel industry according to claim 1 is characterized in that: In step 1), direct CO2 emissions include emissions from fossil fuel combustion and emissions from the steel production process. Emissions from the steel production process include emissions from thermal decomposition of iron ore flux and emissions generated during the decarbonization of steel; indirect CO2 emissions come from fossil fuels, iron ore flux, electrodes and upstream activities. Upstream activity emissions cover CO2 emissions from mining to mineral processing, transportation and electricity consumption-related processes; the long process route includes coke production, sintering, blast furnace ironmaking, converter steelmaking and steel processing; the short process route includes electric furnace steelmaking and steel processing.

3. The comprehensive evaluation method for the long-term economic decarbonization path for the steel industry according to claim 1 is characterized in that: In step 1), the calculation formula for the direct and indirect CO2 emissions per unit product and the total CO2 emissions of each process of the long process and short process route is: in, and They represent the direct and indirect CO2 emissions per unit product of process i in route m, respectively; and They represent the amount of fuel, flux, electrode and power consumed per unit product of process i in route m respectively; and are the direct CO2 emission factors of various fuels and fluxes respectively; the steel ratio coefficients of blast furnace ironmaking and converter steelmaking in the long process path are SR BF and SR BOF Indicates; C p and C r are the average carbon contents of pig iron and rolled steel, respectively; and They are the indirect CO2 emission factors of various fuels, fluxes and electrodes; the CO2 emission factor of electricity consumption is EF ele express; Represents the total CO2 emissions per unit product of process i in route m.

4. The comprehensive evaluation method for the long-term economic decarbonization path for the steel industry according to claim 1 is characterized in that: In step 2), the economic benefit is quantified by the carbon reduction cost and the benefit-cost ratio, the environmental benefit is quantified by the payback period, and the technical maturity is quantified by the service life and penetration rate.

5. The comprehensive evaluation method for the long-term economic decarbonization path for the steel industry according to claim 4 is characterized in that: In step 2), the economic and environmental benefits are quantified by: Among them, ACC j and OM j Represent the annual investment and operating cost of technology j respectively; F j represents the capital investment in the life cycle of technology j; d represents the discount rate; L j represents the service life of technology j; CCR j ,PPSI j , and BCR j They represent the carbon reduction cost, static investment payback period and cost-effectiveness ratio of technology j, including energy saving and CO2 emission reduction benefits; and represents the energy saving and CO2 emission reduction per ton of crude steel by technology j; E E and represent the actual energy price and CO2 emission price respectively.

6. The comprehensive evaluation method for the long-term economic decarbonization path for the steel industry according to claim 1 is characterized in that: In the step 3), the method for determining the optimal technology development path is: based on the carbon emission results obtained in step 1) and the evaluation results of each decarbonization technology in step 2), as well as the production structure, energy supply model and output of the steel industry, under the constraints of steel demand, energy consumption control and technological development, determine the optimal dynamic changes in the penetration rates of various technologies, and determine the optimal technology development path based on the optimal dynamic changes in the technology penetration rates.

7. The comprehensive evaluation method for the long-term economic decarbonization path for the steel industry according to claim 1 is characterized in that: In step 3), the impact of the combination of different decarbonization technologies on the carbon emissions and economic benefits of the steel industry is evaluated according to the optimal technology development path. The specific method is: The goal is to reduce the total cumulative cost and CO2 emissions during the analysis period by applying various weight factors under different preference scenarios to adjust the total cumulative cost and CO2 emissions. The objective function is defined as follows: w1+w2=1#(###) Among them, w1 and w2 represent the relative weight factors assigned to CO2 emission and cost targets, respectively; represents the total cumulative CO2 emissions from the steel industry during the analysis period; and Respectively represent The maximum and minimum values ​​of cost represent the total cumulative cost of the steel industry during the analysis period; cost max and cost min Represent the maximum and minimum values ​​of cost respectively; The calculation of cost and related intermediate variables is as follows: Among them, r m Indicates the proportion of long-process and short-process routes in the steel industry; andQ E represents the total CO2 emissions and total energy consumption of the steel industry in the time interval [0, T]; t is a time variable with one step per year; SR m,i represents the steel ratio coefficient of process i in route m; P t represents the crude steel production at time t; and represents the CO2 emission intensity and energy consumption intensity of process i of route m at time t and t-1 respectively; j represents the technology applicable to process i of route m; J j Represents the total number of available technologies; pr j,t and pr j,t-1 denote the penetration rate of technology j at time t and t-1, respectively; and They represent the equivalent CO2 emission intensity and energy consumption intensity of the steel industry at time t; S j,t Cap represents the capacity of technology j at time t; m,i,t N represents the production capacity of process i of route m at time t; j,t represents the capacity of technology j introduced at time t through investment; e j,t represents the aging rate of technology j at time t; represents the capacity of technology j that is eliminated at time t; L j represents the service life of technology j; represents the annual CO2 emission reduction potential of technology j; cost represents the total cost of the steel industry in the time interval [0, T], including the investment and operating costs of the applicable technology as well as the fuel and CO2 costs; ACC j,t represents the annualized investment cost of technology j at time t; F j,t represents the investment cost of technology j at time t; OM j,t represents the operating cost of technology j at time t; and denote the real-time CO2 emissions and fuel prices at time t respectively; The constraints are: Supply and demand balance equation: Cap m,i,t =P m,i,t =SR m,i ×P t #(###) Energy saving target constraints: Technology development constraints: in, represents the decline rate of energy consumption intensity of the steel industry at time t; α j represents the initial growth rate of technology j, and j′ represents the technology of the same type as technology j and has a substitution effect.

8. A comprehensive evaluation system for the long-term economic decarbonization path of the steel industry, used to implement the method described in any one of claims 1 to 7, characterized in that: include: The life cycle CO2 emission analysis module is used to analyze the life cycle CO2 emissions of the steel industry and calculate the direct and indirect CO2 emissions per unit product and the total CO2 emissions for each process of the long and short process routes; A multi-criteria technology assessment module, which is used to evaluate the decarbonization technology of the steel industry from multiple criteria, including economic benefits, environmental benefits and technological maturity as three evaluation criteria; The multi-technology dynamic optimization module is used to determine the optimal technology development path by combining the carbon emission results obtained by the life cycle CO2 emission analysis module and the evaluation results of each decarbonization technology in the multi-standard technology evaluation module, and evaluate the impact of the combination of different decarbonization technologies on the carbon emissions and economic benefits of the steel industry based on the optimal technology development path.

Images