A Multi-Scale Cross-Media Carbon Pollution Coupling Flow Direction Modeling Method Based on Process Nodes

Abstract

The application discloses a multi-scale cross-medium carbon pollution coupling flow direction modeling method based on process nodes, and belongs to the technical field of carbon pollution emission analysis. Based on long-process and short-process energy material metabolism in aluminum production process, aluminum element flow models and carbon pollution coupling emission flow models in long-process and short-process production processes are established. Based on the use of raw materials and energy in the production process, the transfer emission of CO2eq is calculated, and spatial transfer models at the provincial scale and the national scale are established. Based on multi-scale greenhouse gas emission and multi-medium pollutant emission data, a multi-medium emission factor model is established. The aluminum element flow model and the carbon pollution coupling emission flow model, the spatial transfer model and the multi-medium emission factor model are combined to establish a multi-scale cross-medium carbon pollution coupling flow direction model based on process nodes. The application focuses on the emission driven by spatial transfer, makes the analysis more rigorous and comprehensive, and realizes real-time monitoring of carbon pollution emission.

Description

Technical Field

[0001] This invention relates to the field of carbon pollution emission analysis technology, and in particular to a multi-scale cross-media carbon pollution coupling flow direction modeling method based on process nodes. Background Technology

[0002] Currently, research on aluminum material flow and greenhouse gas emissions mainly focuses on macro-level national assessments and individual provincial evaluations, lacking bottom-up plant-source scale statistics. Furthermore, most studies are primarily based on carbon emissions, neglecting the impact of pollutant emissions. More importantly, the carbon footprint of aluminum products produced through long-process and short-process methods differs significantly. Considering only direct emissions from the calcination and smelting stages would severely underestimate the overall emission level of the aluminum industry chain and emissions caused by spatial transfer. Additionally, emissions from electricity use are a significant source of emissions in the production process. Previous studies primarily relied on a nationally unified electricity emission factor. However, it should be noted that due to differences in energy structures and the proportion of green electricity in different provinces, provincial electricity emission factors also vary, leading to some errors in previous estimates of electricity emissions and undoubtedly increasing the inaccuracy of carbon emission accounting in the aluminum industry chain. Moreover, the environmental impact of aluminum production is not limited to gaseous media; solid waste generated and water pollution are also considered in multi-media emission factor models.

[0003] In summary, a multi-scale, cross-media carbon-pollution coupling flow model based on process nodes is needed to address the significant errors in the estimation of aluminum material flow and carbon emission flow in existing technologies, as well as the lack of comprehensive consideration of pollutant emissions, including emissions driven by spatial transfer and emissions coupled across multiple media. Summary of the Invention

[0004] The purpose of this invention is to propose a multi-scale cross-media carbon pollution coupling flow direction modeling method based on process nodes, including:

[0005] Based on the energy and material metabolism in the long and short processes of aluminum production, we establish aluminum element flow models and carbon pollution coupled emission flow models in the long and short processes of aluminum production.

[0006] Based on the use of raw materials and energy in the production process, the transfer emissions of CO2eq are calculated, and spatial transfer models at the provincial and national scales are established.

[0007] Based on multi-scale greenhouse gas emissions and multi-media pollutant emissions data, and combined with solid waste resource utilization, greenhouse gas emissions are tracked, multi-media pollutant environmental fate analysis is conducted, and a multi-media emission factor model is established.

[0008] By integrating aluminum element flow model, carbon pollution coupled emission flow model, spatial transfer model, and multi-media emission factor model, a multi-scale cross-media carbon pollution coupled flow direction model based on process nodes is established.

[0009] The aluminum element flow model is as follows:

[0010]

[0011] Al Input-rec =∑(I Al,EOF ×C Al,Rec (2)

[0012] In the formula, Al Input It is the total input of aluminum in a long-process manufacturing process; I Al,pro,p and I Al,imp,p These are the extraction and input quantities of bauxite in process p, respectively; C Al,p This refers to the percentage of aluminum content in the aluminum resource input during process p; O Al,loss,p and O Al,exp,p These represent the loss and output of aluminum resources at each stage of the lifecycle in process p; L Al,p It is the percentage of aluminum resources lost in process p; Al Input-rec It is the total amount of aluminum input in the short-process production; I Al,EOF It is the amount of aluminum-containing waste recycled; C Al,Rec It represents the percentage of aluminum in the recycled waste.

[0013] The carbon-pollution coupled emission flow model is as follows:

[0014]

[0015] EF anode =NC anode ×(1-S anode -A anode )×44 / 12 (8)

[0016] E CO2,eq,t =EF t ×N Al (9)

[0017]

[0018] E Hg,p =∑F f,p ×C f,Hg ×(1-R Hg )+Power p ×EI r,Hg (12)

[0019]

[0020] E NOx,p =∑F f,p ×EF p,NOx ×(1-R NOx )+Power p ×EI r,NOx (14)

[0021]

[0022] In the formula, E CO2eq E represents the total emissions of carbon dioxide equivalent in a long process. Fuel,CO2eq E Material,CO2eq E Electricity,CO2eq and E Limestone,CO2eq These are carbon dioxide emissions from fuel consumption, carbon anode reduction, electricity use, and calcium carbonate decomposition, respectively; F f,p It refers to the amount of fuel f consumed in process p; NCV f The average lower heating value of fuel f, in GJ / t and GJ / 10 4 Nm 3 C f,C It is the carbon content per unit calorific value of fuel f, tC / GJ; O f It is the carbon oxidation rate of fuel f, %; Power p It refers to the amount of electricity used in process p; EI r,CO2 This represents the carbon emission intensity of electricity used in province r; EF anode It is the carbon dioxide emission factor consumed by the carbon anode, tCO2 / t-Al; N Al EF represents the annual production of primary aluminum, in tons; L represents the consumption of limestone, in tons; limestone The emission factors for burning limestone are tCO2 / t-Al; NC anode The annual net consumption of carbon anodes per ton of aluminum is 0.42 tC / t-Al; S anode It is the average sulfur content of the carbon anodes during the year, 2%; A anode The average ash content of the carbon anodes during the year is 0.4%; E CO2eq,j These represent the emissions of gases N₂O, CF₄, and C₂F₆, respectively; t represents the emissions of gases N₂O, CF₄, and C₂F₆, E₂O, and E₂F₆. CO2,eq,t These represent the emissions of gases N₂O, CF₄, and C₂F₆, respectively; EF t The emission factors for N2O, CF4, and C2F6 are 3.318 kg N2O / t-Al, 0.034 kg CF4 / t-Al, and 0.0034 kg C2F6 / t-Al, respectively; GWP CF4 and GWP C2F6 The global warming potential (GWP) values ​​for CF4 and C2F6 are 6500 and 9200, respectively; ESO2,p E Hg,p E PM2.5,p and E NOx,p These represent SO2, Hg, and PM in the long process step p. 2.5 NOx emissions; C f,S and C f,Hg These are the sulfur (S) and hydrogen (Hg) content in fuel f, respectively; R SO2 ,R Hg ,R PM2.5 ,R NOx These are SO2, Hg, and PM under different control measures. 2.5 NOx removal efficiency (%); EI r,SO2 EI r,Hg EI r,PM2.5 EI r,NOx These represent the SO2, Hg, and PM2.5 produced in province r through process p using electricity. 2.5 NOx emission intensity; a is the sulfur retention rate in ash, %; b is the content of released ash, %; EF p,PM2.5 It refers to the ash content in the fuel; EF p,NOx It is the uncontrolled factor of NOx in process p; E CO2,rec This refers to the CO2 emissions from short-process manufacturing; F f,rec Fuel consumption (f) in short-process operations; Power rec This represents the amount of electricity used in short-process operations.

[0023] The spatial transfer model is as follows:

[0024] VE i,j =EI j ×TB i,j (16)

[0025] EI j =E j ×P j (17)

[0026] In the formula, VE represents the spatial transfer emissions from raw material and energy exporting province j to raw material and energy importing province i; EI j The emission intensity of province j, which exports raw materials and energy; TB i,j For input province i, input the raw material quantity and energy quantity from output province j; E j For the production units of raw materials and energy in province j, CO2eq, PM 2.5 Emissions of SO2, NOx, and Hg; P j The raw material and energy production of province j.

[0027] The formula for calculating the transferred emissions of CO2eq is as follows:

[0028]

[0029] E Tran =W d ×D c ×EEOI c (19)

[0030]

[0031] In the formula, E e This represents China's total CO2eq emissions during the export of aluminum-containing products, where n represents different locations; E Al and E Tran These are CO2eq emissions from the production and transportation processes of aluminum-containing products; W d D is the transport volume of aluminum-containing products, expressed in tons. c It is the distance (Nm) for transporting aluminum-containing products to c; EEOI c These are energy efficiency indicators for energy delivered to different locations (c), expressed as GCO2 / t / NM; E import This refers to China's total CO2eq emissions during the import of aluminum-containing products; E Al-pro and E embodied These are CO2eq emissions from the production and transportation processes of aluminum-containing products in locations other than China.

[0032] The multi-media emission factor model is as follows:

[0033] P waste,p,k =P Al ×a waste,p,k (twenty one)

[0034] R recycle =R mud +R SPL +R dross +R anode (twenty two)

[0035] In the formula, P waste,p,k P represents the amount of solid waste k generated during process p, expressed in t. Al This refers to the production volume of aluminum-containing products, expressed in tons (t); a waste,p,k This is the coefficient of solid waste k generated per unit of aluminum-containing product produced in process p; the coefficient for red mud is 1.0–1.8; aluminum ash slag is 6–8 kg in primary aluminum smelting and casting, 20–50 kg in aluminum product processing, and 80–100 kg in aluminum alloy recycling; overhaul slag is 20–30 kg; and anode carbon slag is 8–12 kg; R recycle R mud R SPL R dross and R anodeThese are the total amount of solid waste resources utilized, and the amount of solid resources utilized from red mud, overhaul slag, aluminum ash slag, and anode carbon slag.

[0036] The multi-scale cross-media carbon pollution coupling flow direction model based on process nodes is as follows:

[0037] E g =E g,mining +E g,refining +E g,smelting +E g,manufacturing +E g,recycling +E g,exporting -E g,importing (twenty three)

[0038] In the formula, E g E represents the total carbon emissions during the long process. g,mining E is responsible for carbon emissions during bauxite mining. g,refining Carbon emissions from bauxite smelting; E g,smelting For carbon pollution emissions during the alumina refining process; E g,manufacuring Carbon emissions from the semi-processing and processing of aluminum ingots; E g,recycling Carbon pollution emissions from aluminum product recycling; E g,exprorting The cumulative carbon pollution emissions from exported aluminum products; E g,importing This reduces carbon emissions from imported aluminum products.

[0039] The beneficial effects of this invention are as follows:

[0040] This invention employs a bottom-up statistical approach to accurately quantify the emission levels of greenhouse gases and multi-media pollutants from point sources in each process step. Using aluminum as the basic element, it combines the carbon and pollution emissions from each process step to form a spatialized evaluation model of the aluminum-carbon-pollution coupled flow. This model can track the input and output of upstream and downstream industries and establish spatial transfer models of carbon and pollution emissions at different scales, supporting the refined allocation of carbon and pollution reduction responsibilities from the national to the provincial, municipal, industrial park, and enterprise levels. By tracking the flow of carbon and pollution emissions from each process step from a life-cycle perspective, it focuses on emissions driven by spatial transfer, establishing a spatial transfer model for energy and raw materials. This makes the analysis more rigorous and comprehensive, and enables real-time monitoring of carbon and pollution emissions. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the multi-scale cross-media carbon pollution coupling flow direction modeling method based on process nodes according to the present invention;

[0042] Figure 2 This diagram illustrates the spatialization of aluminum-carbon-pollution coupling flow and the environmental fate of multi-media carbon pollution. Detailed Implementation

[0043] This invention proposes a multi-scale cross-media carbon pollution coupling flow direction modeling method based on process nodes. The invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0044] Figure 1 This is a schematic diagram of the multi-scale cross-medium carbon pollution coupling flow modeling method based on process nodes according to the present invention. Because existing technologies lack an exploration of corresponding carbon emissions from a full life-cycle perspective—generally focusing on the direct carbon emissions from the key electrolytic aluminum smelting process—the estimated carbon emissions per ton of aluminum produced are underestimated. Furthermore, since existing technologies fail to fully consider the pollutant emissions from energy and electricity consumption during aluminum production, they inevitably severely underestimate the environmental problems caused by aluminum production.

[0045] Therefore, based on the aluminum-carbon-pollution coupled flow industrial chain carbon pollution emission model provided in this embodiment, the production, loss, and recycling of raw materials and products at each stage are considered, and the energy and electricity consumption and usage at each stage are monitored. Finally, a multi-scale cross-media carbon pollution coupled flow model based on process nodes is obtained. The specific modeling method is as follows:

[0046] 1. Establish aluminum element flow models and carbon pollution coupled emission flow models in long-process and short-process aluminum production. Based on the energy and material metabolism of long-process and short-process aluminum production, track the aluminum element flow and the carbon pollution emissions of the whole process. The long process includes bauxite mining, bauxite smelting, electrolytic alumina, primary aluminum processing and end product production. The main energy inputs include coal, oil, natural gas and electricity, and the auxiliary material inputs include carbon anodes, calcium carbonate and sodium hydroxide. The model includes: using formula (1) to construct the aluminum element flow model of the whole life cycle, and using formula (3-14) to construct the greenhouse gas (CO2eq) and pollutant (NOx, SO2, PM) of the whole process by process. 2.5 A coupled emission model for Hg was established. The short-process production involves pretreatment, smelting, and processing of aluminum scrap to obtain recycled aluminum. Major energy inputs include coal and electricity, while raw material inputs include scrap aluminum. Formula (2) was used to construct a short-process aluminum element flow model. The carbon dioxide (CO2) and pollutants (NOx, SO2, PM2.5) emissions from the short-process production were evaluated. 2.5 The aluminum industry chain is divided into two stages: aluminum waste pretreatment and recycled aluminum smelting and casting, based on emissions of Hg. The direct CO2 emissions (energy consumption) and indirect CO2 emissions (electricity) of each process in the short process are calculated using formula (15). Similarly, the emissions of pollutants in the long process are calculated using formulas (11-14).

[0047]

[0048] Al Input-rec =∑(I Al,EOF ×C Al,Rec(2)

[0049] In the formula, Al Input It is the total amount of aluminum input in a long-process manufacturing process; I Al,pro,p and I Al,imp,p These are the mining and import volumes of bauxite in process p, respectively; C Al,p This refers to the percentage of aluminum content in the aluminum resources (bauxite, alumina, aluminum ingots) input during process p; O Al,loss,p and O Al,exp,p These represent the loss and export volume of aluminum resources at each stage of the lifecycle in process p; L Al,p It is the percentage of aluminum resources lost in process p; Al Input-rec It is the total amount of aluminum input in the short-process production; I Al,EOF It is the amount of aluminum-containing waste recycled; C Al,Rec It represents the percentage of aluminum in the recycled waste.

[0050]

[0051] EF anode =NC anode ×(1-S anode -A anode )×44 / 12 (8)

[0052] In the formula, E CO2eq E represents the total carbon dioxide equivalent emissions in long-process technologies. Fuel,CO2eq E Material,CO2eq E Electricity,CO2eq and E Limestone,CO2eq These are carbon dioxide emissions from fuel consumption, carbon anode reduction, electricity use, and calcium carbonate decomposition, respectively; F f,p It refers to the amount of fuel f consumed in process p; NCV f The average lower heating value (GJ / t and GJ / 10,000 Nm³) of fuel f (coal, oil, natural gas) 3 );C f,C It is the carbon content per unit calorific value of fuel f (tC / GJ); O f It is the carbon oxidation rate (%) of fuel f; Power p It refers to the amount of electricity used in process p; EI r,CO2 This represents the carbon emission intensity of electricity used in province r; EF anode It is the carbon dioxide emission factor consumed by the carbon anode (tCO2 / t-Al); N Al EF represents the annual primary aluminum production (t); L represents the limestone consumption; limestone It is the emission factor (tCO2 / t-Al) from burning limestone; NC anode The annual net consumption of carbon anodes per ton of aluminum is 0.42 tC / t-Al; S anodeIt is the average sulfur content (2%) of the carbon anodes within the year; A anode It is the average ash content of the carbon anodes within the year (0.4%).

[0053] E CO2,eq,t =EF t ×N Al (9)

[0054]

[0055] In the formula, t represents gases N₂O, CF₄, C₂F₆, and E CO2,eq,t These represent the emissions of gases N₂O, CF₄, and C₂F₆, respectively; EF t The emission factors for N2O, CF4, and C2F6 are 3.318 kg N2O / t-Al, 0.034 kg CF4 / t-Al, and 0.0034 kg C2F6 / t-Al, respectively; GWP CF4 and GWP C2F6 The values ​​are the global warming potential (GWP) values ​​for CF4 and C2F6, respectively, and are 6500 and 9200.

[0056]

[0057] E Hg,p =∑F f,p ×C f,Hg ×(1-R Hg )+Power p ×EI r,Hg (12)

[0058]

[0059] E NOx,p =∑F f,p ×EF p,NOx ×(1-R NOx )+Power p ×EI r,NOx (14)

[0060] In the formula, E SO2,p E Hg,p E PM2.5,p and E NOx,p These represent SO2, Hg, and PM in the long process step p. 2.5 NOx emissions; C f,S and C f,Hg These are the sulfur (S) and hydrogen (Hg) content in fuel f, respectively; R SO2 ,R Hg ,R PM2.5 ,R NOxThese are SO2, Hg, and PM under different control measures. 2.5 NOx removal efficiency; EI r,SO2 EI r,Hg EI r,PM2.5 EI r,NOx These represent the SO2, Hg, and PM2.5 used in process p of production in province r, respectively. 2.5 NOx emission intensity; a is the sulfur retention rate in ash (%); b is the content of released ash (%); EF p,PM2.5 It refers to the ash content in the fuel; EF p,NOx It is the uncontrolled factor of NOx in process p.

[0061]

[0062] In the formula, E CO2,rec This refers to the CO2 emissions from short-process manufacturing; F f,rec Fuel consumption (f) in short-process operations; Power rec This represents the amount of electricity used in short-process operations.

[0063] 2. Establish spatial transfer models at the provincial and national scales. Obtain information on the transfer of carbon emissions driven by raw materials and energy in the production processes at the provincial and national scales, involving transactions of coal, electricity, bauxite, alumina, and aluminum ingots. Utilize bulk commodity logistics networks to establish spatial transfer matrices for aluminum resources (bauxite, alumina, and aluminum ingots), coal, and electricity. Based on real-time factory production data and previously compiled multi-scale aluminum-carbon-pollution databases at the national, provincial, and enterprise levels, establish spatial transfer matrices for aluminum-coal-electricity in the production processes. The provincial-level spatial transfer carbon emission models for energy and raw materials include: an aluminum resource transfer matrix, including input and output provinces and corresponding transport volumes; a coal transfer matrix, including input and output provinces, coal transport volumes, and transport methods (railway, road, and combined transport); and an electricity transfer matrix, including input and output provinces and electricity transmission volumes. Combine the raw material and energy transfer matrices with transport emission factors to establish a process-based spatial transfer model of carbon emissions from the exporting to the importing region throughout the entire life cycle, using formulas (16-17). For aluminum resource exporting regions, the energy consumption level of the mining process is also considered, and formulas (18-19) are used. Through the national-scale spatial transfer database of aluminum resources, the corresponding aluminum resource input and output are identified, and the cumulative reduction of CO2eq transfer emissions in aluminum resource importing regions is calculated using formula (20) by utilizing the aluminum resource spatial transfer matrix and the emission factor of the transportation process.

[0064] VE i,j =EI j ×TB i,j (16)

[0065] EI j =E j ×P j (17)

[0066] In the formula, VE represents the spatial transfer emissions from raw material / energy exporting province j to raw material / energy importing province i; EI j The emission intensity of province j, which exports raw materials and energy; TB i,j For input province i, input the raw material quantity and energy quantity from output province j; E j For the production units of raw materials and energy in province j, CO2eq, PM 2.5 Emissions of SO2, NOx, and Hg; P j The raw material and energy production of province j.

[0067]

[0068] E Tran =W d ×D c ×EEOI c (19)

[0069] In the formula, E e This represents China's total CO2eq emissions during the export of aluminum-containing products, where n represents different locations; E Al and E Tran These are CO2eq emissions from the production and transportation processes of aluminum-containing products; W d D is the transport volume of aluminum-containing products, expressed in tons. c It is the distance (Nm) for transporting aluminum-containing products to c; EEOI c It is the energy efficiency index for energy delivered to different locations c, GCO2 / t / NM.

[0070]

[0071] In the formula, E i This refers to China's total CO2eq emissions during the import of aluminum-containing products; E Al and E Tran These are CO2eq emissions from the production and transportation processes of aluminum-containing products outside of China. import This refers to China's total CO2eq emissions during the import of aluminum-containing products; E Al-pro and E embodied These are CO2eq emissions from the production and transportation processes of aluminum-containing products in locations other than China.

[0072] 3. Establish a multi-media emission factor model. Figure 2A schematic diagram of the spatialization of aluminum-carbon-pollution coupling flow and the environmental fate of multi-media carbon pollution. Develop a spatialization evaluation and monitoring technology for aluminum-carbon-pollution coupling flow, incorporate solid waste resource utilization, and track the environmental fate of greenhouse gases and multi-media pollutants. This method is designed as a comprehensive system model of the entire life cycle of the aluminum industry chain based on material flow-energy flow-emission flow. It can be used not only for multi-media carbon pollution emissions of a single aluminum production plant within the accounting boundary, but also for analyzing multi-media carbon pollution emissions and emission reduction responsibility allocation at different spatial scales. Based on the establishment of a multi-scale aluminum industry atmospheric carbon pollution emission system model, a resource utilization method for solid waste throughout the entire life cycle of the aluminum industry is coupled to form a complete multi-media carbon pollution emission model. Formula (21) is used to calculate the amount of solid waste (red mud, overhaul slag, aluminum ash slag, and anode carbon slag) generated in different processes. However, since solid waste has the dual attributes of resources and pollution, it can be recycled and utilized through different means. For example, red mud can be used to achieve synergistic applications with major industries such as steel, chemical, materials, and environmental protection by utilizing its different chemical composition. Formula (22) is used to quantify the amount of solid waste resources utilized in the aluminum industry chain.

[0073] P waste,p,k =P Al ×a waste,p,k (twenty one)

[0074] R recycle =R mud +R SPL +R dross +R anode (twenty two)

[0075] In the formula, P waste,p,k P represents the amount of solid waste k generated during process p, expressed in t. Al This refers to the production volume of aluminum-containing products, expressed in tons (t); a waste,p,k This is the coefficient of solid waste k generated per unit of aluminum-containing product produced in process p; the coefficient for red mud is 1.0–1.8; aluminum ash slag is 6–8 kg in primary aluminum smelting and casting, 20–50 kg in aluminum product processing, and 80–100 kg in aluminum alloy recycling; overhaul slag is 20–30 kg; and anode carbon slag is 8–12 kg; R recycle It is the total amount of solid waste resource utilization, R mud R SPL R dross and R anode These are the solid resource utilization amounts of red mud, overhaul slag, aluminum ash slag, and anode carbon slag.

[0076] 4. Integrating the aluminum element flow model, carbon pollution coupled emission flow model, spatial transfer model, and multi-media emission factor model, a multi-scale cross-media carbon pollution coupled flow direction model based on process nodes is established. Gas medium carbon pollution emissions include the production part and the spatial transfer part. Emissions in the production stage include emissions from bauxite mining, bauxite refining, alumina smelting, primary aluminum processing, and waste aluminum recycling. Spatial transfer emissions include transfer emissions during the spatial transfer of coal and electricity. Emissions in the transportation stage include transfer emissions during the import and export of aluminum resources in China. Based on the multi-dimensional material flow model, a multi-scale cross-media carbon pollution coupled flow direction model based on process nodes is established as shown in formula (23), where g represents CO2eq, NOx, SO2, PM 2.5 And Hg. Identifying emissions across the multi-media, full-lifecycle aluminum industry chain provides a scientific basis for developing targeted emission reduction strategies and policies.

[0077] E g =E g,mining +E g,refining +E g,smelting +E g,manufacturing +E g,recycling +E g,exporting -E g,importing (twenty three)

[0078] In the formula, E g E represents the total carbon emissions during the long process. g,mining E is responsible for carbon emissions during bauxite mining. g,refining Carbon emissions from bauxite smelting; E g,smelting For carbon pollution emissions during the alumina refining process; E g,manufacuring Carbon emissions from the semi-processing and processing of aluminum ingots; E g,recycling Carbon pollution emissions from aluminum product recycling; E g,exprorting The cumulative carbon pollution emissions from the export of aluminum products; E g,importing Reduced carbon emissions from imported aluminum products.

[0079] Based on the full life-cycle analysis of aluminum element flow, this case study builds a model for the coupled flow of aluminum, carbon, and pollution and multi-media emissions in 2020. A coupled flow model of aluminum, carbon, and pollution in China in 2020 is constructed to track greenhouse gas and multi-media pollutant emissions, covering 46 alumina production plants, 116 primary aluminum production plants, and 133 recycled aluminum production plants. The model statistically analyzes fuel consumption, electricity use, and auxiliary material consumption in the aluminum industry from bauxite mining to the production of semi-finished aluminum products. The emission factor method is used to establish the plant-level point source full life-cycle carbon dioxide equivalent (CO2eq) and pollutant (PM) emissions. 2.5A coupled emission model for (NOx, SO2, and Hg) was developed. The aluminum element flow model identified a total aluminum input of 49,150 kt in China in 2020, of which 22,300 kt came from primary bauxite mining and 26,850 kt from direct input. The multi-media emission factor model showed that in 2020, after bauxite smelting, alumina electrolysis, and primary aluminum processing, 76.5% of aluminum ultimately entered end products, while 23.5% was lost to the environment or entered into comprehensive utilization stages along with tailings, red mud, and waste residue. In the end-consumer stage, due to the spatial transfer of aluminum products, approximately 25% of the aluminum produced is used in transportation, 35% in electronics and electrical appliances, 15% in packaging materials, and 25% in durable goods, resulting in the output of aluminum products through spatial transfer matrices. The remaining aluminum products continue to flow between provinces. After being scrapped, 19.4% of reusable consumer goods are recycled and reused through short-process aluminum smelting. In 2020, Chinese aluminum plants emitted a total of 380 Mt CO2eq, 277 kt SO2, 5,552 kg Hg, 491 kt NOx, and 389 kt PM2.5. 2.5 The electrolytic alumina process contributes approximately 66% of this, primarily due to coal combustion and carbon anode reduction processes.

[0080] Atmospheric carbon emissions in this implementation case include CO2, NOx, SO2, and PM2.5. 2.5 The emissions include hydrogen (Hg), solid waste (red mud, overhaul slag, aluminum ash slag, and anode carbon slag), and water pollution (COB, BOD, nitrogen oxides, carbon dioxide, etc.). Based on a coupled flow model of aluminum-carbon-pollution material flow, this study analyzes the carbon pollution emissions and solid waste resource utilization in the multi-media emissions of the aluminum industry chain throughout its entire life cycle. It focuses on emissions driven by spatial transfer, making the analysis more rigorous and comprehensive, and enabling real-time monitoring of carbon pollution emissions.

Claims

1. A process node based multi-scale cross-media carbon pollution coupling flow direction modeling method, characterized in that, The application relates to a multi-scale and multi-medium carbon-pollutant coupling flow direction model based on a process node. The application relates to a multi-scale and multi-medium carbon-pollutant coupling flow direction model based on a process node. The application relates to a multi-scale and multi-medium carbon-pollutant coupling flow direction model based on a process node. Al Input-rec =∑(I Al,EOF ×C Al,Rec ) (2) wherein Al Input is the total input of aluminum element in long process production process; I Al,pro,p and I Al,imp,p are the mining amount and input amount of bauxite in process p, respectively; C Al,p is the aluminum content percentage of input aluminum resources in process p; O Al,loss,p and O Al,exp,p are the loss amount and output amount of each life cycle aluminum resource in process p, respectively; L Al,p is the aluminum content percentage of lost aluminum resources in process p; Al Input-rec is the total input of aluminum element in short process production process; I Al,EOF is the amount of aluminum-containing waste recovered; C Al,Rec is the aluminum content percentage in recovered waste; The application relates to a multi-scale and multi-medium carbon-pollutant coupling flow direction model based on a process node. EF anode = NC anode × (1-S anode -A anode ) × 44 / 12 (8) E CO2,eq,t = EF t x N Al (9) E Hg,p =∑F f,p ×C f,Hg ×(1-R Hg )+Power p ×EI r,Hg (12) E NOx,p = ∑F f,p × EF p,NOx × (1 - R NOx )+ Power p × EI r,NOx (14) wherein E CO2eq is the total emission of carbon dioxide equivalent in the long process, E Fuel,CO2eq , E Material,CO2eq , E Electricity,CO2eq and E Limestone,CO2eq are the carbon dioxide emissions of fuel consumption, carbon anode reduction, electricity use and calcium carbonate decomposition, respectively; F f,p is the consumption of fuel f in process p; NCV f is the average lower calorific value of fuel f, GJ / t and GJ / 10 4 Nm 3 ; C f,C is the carbon content per unit heat value of fuel f, tC / GJ; O f is the carbon oxidation rate of fuel f, %, Power p is the amount of electricity used in process p; EI r,CO2 represents the carbon emission intensity of using electricity in province r; EF anode is the carbon dioxide emission factor of carbon anode consumption, tCO2 / t-Al; N Al is the production of primary aluminum within the year, t; L is the consumption of limestone, t; EF limestone is the emission factor of burning limestone, tCO2 / t-Al; NC anode is the net consumption of carbon anode per ton of aluminum within the year, 0.42 tC / t-Al; S anode is the average sulfur content of carbon anode within the year, 2%; A anode is the average ash content of carbon anode within the year, 0.4%; t represents gas N2O, CF4, C2F6, E CO2,eq,t respectively represent the emission of gas N2O, CF4, C2F6; EF t are the emission factors of N2O, CF4, and C2F6 gas, respectively, with values of 3.318 kg N2O / t-Al, 0.034 kg CF4 / t-Al, and 0.0034 kg C2F6 / t-Al; GWP CF4 and GWP C2F6 are the global warming potential values of CF4 and C2F6, GWP, with values of 6500 and 9200; E SO2,p , E Hg,p , E PM2.5,p , and E NOx,p are the emissions of SO2, Hg, PM 2.5 , NOx in long process p; C f,S and C f,Hg are the S content and Hg content in fuel f, %; R SO2 , R Hg , R PM2.5 , R NOx are the removal efficiencies of SO2, Hg, PM 2.5 , NOx under different control measures, %; EI r,SO2 , EI r,Hg , EI r,PM2.5 , EI r,NOx respectively represent the emission intensity of SO2, Hg, PM 2.5 , NOx produced by using electricity in process p in province r; a is the retention rate of sulfur in ash, %; b is the content of released ash, %; EF p,PM2.5 is the ash content in the fuel; EF p,NOx is the uncontrolled factor of NOx during the process p; E CO2,rec is the total CO2 emission in the short process; F f,rec is the fuel f usage in the short process; Power rec is the power usage in the short process; The application relates to a multi-scale and multi-medium carbon-pollutant coupling flow direction model based on a process node. The application relates to a multi-scale and multi-medium carbon-pollutant coupling flow direction model based on a process node. The application relates to a multi-scale and multi-medium carbon-pollutant coupling flow direction model based on a process node.

2. The process node based multi-scale cross-media carbon pollution coupling flow direction modeling method according to claim 1, characterized in that, The application relates to a multi-scale and multi-medium carbon-pollutant coupling flow direction model based on a process node. VE i,j = EI j x TB i,j (16) EI j = E j x P j (17) where VE is the spatially transferred emission from the raw material and energy output province j to the raw material and energy input province i; EI j is the emission intensity of the raw material and energy output province j. TB i,j Input quantity of raw material and energy from output province j to input province i; E j CO2eq, PM produced per unit of raw material or energy in province j; P 2.5 Emission of SO2, NOx and Hg in province j; P j Production of raw material and energy in province j.

3. The process node based multi-scale cross-media carbon pollution coupling flow modeling method according to claim 1 or 2, characterized in that, The application relates to a multi-scale and multi-medium carbon-pollutant coupling flow direction model based on a process node. E Tran = W d x D c x EEOI c (19) where E e is the total CO2eqemissions from China in exporting the aluminum-containing products, n represents different locations; E Al and E Tran are the CO2eqemissions from the production process and the transportation process of the aluminum-containing products, respectively; W d is the transportation quantity of the aluminum-containing product d, t; D c is the distance of transporting the aluminum-containing product to c, NM; EEOI c is the energy efficiency index of transporting to different places c, GCO2 / t / NM; E import is the total CO2eqemissions of China in the process of importing the aluminum-containing product; E Al-pro and E embodied are the CO2eqemissions of the aluminum-containing product in the production process and the transportation process at other places than China, respectively.

4. The process node based multi-scale cross-media carbon pollution coupling flow direction modeling method according to claim 1, characterized in that, The application relates to a multi-scale and multi-medium carbon-pollutant coupling flow direction model based on a process node. P waste,p,k = P Al × a waste,p,k (21) R recycle = R mud + R SPL + R dross + R anode (22) In the formula, P waste,p,k is the amount of solid waste k generated in process p, t; P Al is the production of aluminum-containing products, t; a waste,p,k is the coefficient of solid waste k generated per unit of aluminum-containing product produced in process p, the coefficient of red mud is 1.0-1.8; aluminum dross in primary aluminum melting and casting, aluminum product processing and aluminum alloy recycling is 6-8 kg, 20-50 kg and 80-100 kg respectively, overhaul slag is 20-30 kg, and anode carbon slag is 8-12 kg; R recycle is the total amount of solid waste resource utilization, R mud , R SPL , R dross and R anode are the solid resource utilization amounts of red mud, overhaul slag, aluminum dross and anode carbon slag respectively.

5. The process node based multi-scale cross-media carbon pollution coupling flow direction modeling method according to claim 1, wherein, The application relates to a multi-scale and multi-medium carbon-pollutant coupling flow direction model based on a process node. The application relates to a multi-scale and multi-medium carbon-pollutant coupling flow direction model based on a process node. The application relates to a multi-scale and multi-medium carbon-pollutant coupling flow direction model based on a process node. The application relates to a multi-scale and multi-medium carbon-pollutant coupling flow direction model based on a process node. The application relates to a multi-scale and multi-medium carbon-pollutant coupling flow direction model based on a process node. The application relates to a multi-scale and multi-medium carbon-pollutant coupling flow direction model based on a process node. The application relates to a multi-scale and multi-medium carbon-pollutant coupling flow direction model based on a process node. The application relates to a multi-scale and multi-medium carbon-pollutant coupling flow direction model based on a process node. The application relates to a multi-scale and multi-medium carbon-pollutant coupling flow direction model based on a process node. The application relates to a multi-scale and multi-medium carbon-pollutant coupling flow direction model based on a process node. The application relates to a multi-scale and multi-medium carbon-pollutant coupling flow direction model based on a process node. The application relates to a multi-scale and multi-medium carbon-pollutant coupling flow direction model based on a process node. The application relates to a multi-scale and multi-medium carbon-pollutant coupling flow direction model based on a process node. The application relates to a multi-scale E g = E g,mining + E g,refining + E g,smelting + E g,manufacturing + E g,recycling + E g,exporting - E g,importing (23) where E g is the total carbon pollution emissions in the long process, E g,mining is the carbon pollution emissions in bauxite mining, E g,refining is the carbon pollution emissions in bauxite smelting; E g,smelting is the carbon pollution emissions in alumina refining; E g,manufacuring is the carbon pollution emissions in aluminium ingot semi-processing and processing; E g,recycling is the carbon pollution emissions in aluminium product recycling; E g,exprorting is the cumulative carbon pollution emissions of exported aluminium products; E g,importing is the reduced carbon pollution emissions of imported aluminium products.

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