Multi-scale cross-medium carbon pollution coupling flow direction modeling method based on process nodes

Abstract

The invention 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 discharge analysis. The method comprises the following steps: establishing an aluminum element flow model and a carbon pollution coupling discharge flow model in long-flow and short-flow production processes based on long-flow and short-flow energy substance metabolism in an aluminum production process; the method comprises the following steps: calculating the transfer emission of CO2eq based on the use conditions of raw materials and energy in sub-process production links, and establishing a space transfer model of a provincial scale and a national scale; establishing a multi-medium emission factor model based on multi-scale greenhouse gas emission and multi-medium pollutant emission data; and integrating the aluminum element flow model, the carbon pollution coupling discharge flow model, the space transfer model and the multi-medium discharge factor model, and establishing a multi-scale cross-medium carbon pollution coupling flow direction model based on process nodes. According to the method, the emission condition under space transfer driving is mainly considered, so that analysis is more rigorous and more comprehensive, and real-time monitoring of carbon pollution emission is realized.

Description

Technical Field

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

[0002] At present, the research on aluminum material flow and greenhouse gas emissions mainly focuses on the macro-national scale and individual provincial assessments, lacking bottom-up statistics at the plant source scale. At the same time, most studies are mainly based on carbon emissions, lacking the impact of pollutant emissions. More importantly, the carbon footprint of aluminum products produced by long processes and short processes is very different. If only the direct emissions from the calcination and smelting links are considered, the overall emission level of the aluminum industry chain and the emissions caused by spatial transfer will be seriously underestimated. In addition, emissions from electricity use are one of the important emission sources in the production process. Previous studies were mainly based on the national unified electricity emission factor. However, it should be noted that due to different energy structures and different proportions of green electricity in various provinces, the electricity emission factors of each province are also different, resulting in certain errors in the previous estimates of electricity emissions, which undoubtedly increases the inaccuracy of carbon pollution emission accounting in the aluminum industry chain. In addition, the environmental impact caused by the aluminum production process is not limited to gaseous media. The solid waste generated and the pollution caused to water bodies are also considered in the multi-media emission factor model.

[0003] In summary, a multi-scale cross-media carbon-pollution coupled flow model based on process nodes is needed to solve the problems of large errors in the estimation of aluminum material flow and carbon emission flow in the existing technology and failure to fully consider pollutant emissions, including emissions driven by spatial transfer and multi-media coupled emissions. Summary of the invention

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

[0005] Based on the energy and material metabolism of the long and short processes in the aluminum production process, the aluminum element flow model and the carbon-pollution coupled emission flow model in the long and short process production processes are established;

[0006] Calculate CO based on the use of raw materials and energy in each production process. 2 The transfer emissions of eq were used to establish spatial transfer models at provincial and national scales;

[0007] Based on multi-scale greenhouse gas emissions and multi-media pollutant emissions data, 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 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 model based on process nodes is established.

[0009] The aluminum element flow model is:

[0010]

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

[0012] In the formula, Al Input is the total input of aluminum element in the long process production process; I Al,pro and I Al,imp are the mining and input of bauxite respectively; C Al,p is the aluminum content percentage of the aluminum resource; Al,loss and O Al,exp are the loss and output of aluminum resources in each life cycle; L Al,p is the percentage of aluminum resources lost in process p; Al Input-rec is the total amount of aluminum input in the short-process production process; I Al,EOF is the amount of aluminum-containing waste recycled; C Al,Rec It is the percentage of aluminum contained in the recycled scrap.

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

[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 is the total carbon dioxide equivalent emission in the long process, E Fuel,CO2eq , E Material,CO2eq , E Electricity,CO2eq and E Limestone,CO2eq are fuel consumption, carbon anode reduction, electricity use and carbon dioxide emissions from calcium carbonate decomposition; 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 calorific 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 electricity used in province r; EF anode is the carbon dioxide emission factor consumed by the carbon anode, tCO 2 / t-Al; N Al is the annual production of primary aluminum, t; L is the consumption of limestone, t; EF limestone is the emission factor for burning limestone, tCO 2 / t-Al;NC anode The net consumption of aluminum carbon anode in a year is 0.42tC / t-Al; S anode is the average sulfur content of carbon anode in the year, 2%; A anode is the average ash content of carbon anode in the year, 0.4%; E CO2eq,j Represents gas N 2 O,CF 4 ,C 2 F 6 The emission of gas N 2 O,CF 4 ,C 2 F 6 , E CO2,eq,t Represents gas N 2 O,CF 4 ,C 2 F 6 Emissions; EF t N2 O,CF 4 and C 2 F 6 The emission factors of gases are 3.318 kg N 2 O / t-Al, 0.034kg CF 4 / t-Al and 0.0034kg C 2 F 6 / t-Al; GWP CF4 and GWP C2F6 For CF 4 and C 2 F 6 The global warming potential, GWP, is 6500 and 9200; E SO2,p ,E Hg,p ,E PM2.5,p and E NOx,p They are respectively SO in the long process step p 2 ,Hg,PM 2.5 , NOx emissions; C f,S and C f,Hg are the S content and Hg content in fuel f respectively; R SO2 ,R Hg ,R PM2.5 ,R NOx They are SO under different control measures. 2 ,Hg,PM 2.5 ,NOx removal efficiency (%); Power p For EI r,SO2 ,EI r,Hg ,EI r,PM2.5 ,EI r,NOx They represent the production of SO using electricity in process p in province r. 2 ,Hg,PM 2.5 , NOx emission intensity; a is the sulfur retention rate in the 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 in process p; E CO2,rec CO in the short process 2 Emissions; F f,rec is the fuel usage in the short process; Power rec It is the amount of electricity used in the short process.

[0023] The spatial transfer model is:

[0024] VE i,j =EI j ×TB i,j (16)

[0025] EI j =E j ×P j (17)

[0026] Where VE is the spatial transfer emissions from raw material and energy exporting province j to raw material and energy importing province i; EI j is the emission intensity of raw material energy exporting province j; TB i,j E is the amount of raw materials and energy that input province i imports from output province j; j CO2 produced per unit of raw materials and energy for province j 2 eq,PM 2.5 ,SO 2 , NOx and Hg emissions; P j is the raw material and energy production of province j.

[0027] CO 2 The calculation formula of the transfer emission of eq is as follows:

[0028]

[0029] E Tran =W d ×D c ×EEOI c (19)

[0030]

[0031] In the formula, E e It is the CO2 emitted by China in the process of exporting aluminum-containing products. 2 eq total emissions, n represents different locations; E Al and E Tran They are CO from the production and transportation of aluminum-containing products. 2 eq emission; W d is the transport volume of aluminum-containing products, t; D c is the distance of conveying aluminum-containing products to c, NM; EEOI c is the energy efficiency index delivered to different locations c, GCO 2 / t / NM;E i It is the CO2 produced by China in the process of importing aluminum-containing products. 2 eq total emission; E Al and E Tran They are the CO2 emissions from the production and transportation of aluminum-containing products in locations other than China. 2 eq emission.

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

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

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

[0035] Where P waste,p,k is the amount of solid waste k generated during process p, t; P Al is the production volume of aluminum-containing products, t; a waste,p,k is the coefficient of solid waste k generated by the production unit of aluminum-containing products in process p, and the red mud coefficient is 1.0-1.8; the aluminum ash slag in primary aluminum casting, aluminum product processing and aluminum alloy regeneration is 6-8kg, 20-50kg and 80-100kg respectively, the overhaul slag is 20-30kg, and the anode carbon slag is 8-12kg; R recycle , R mud , R SPL , R dross and R anode They are the total amount of solid waste resource utilization, the solid resource utilization of red mud, overhaul slag, aluminum ash slag and anode carbon slag.

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

[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 is the total carbon pollution emission in the long process, E g,mining is the carbon emission during bauxite mining, E g,refining E is the carbon pollution emission in the process of bauxite smelting; g,smelting E is the carbon pollution emission in the alumina refining process; g,manufacuring Carbon emissions during semi-processing and processing of aluminum ingots; E g,recycling E is the carbon pollution emission during the recycling process of aluminum products; g,exprorting The accumulated carbon emissions from exported aluminum products; g,importing Reduce carbon emissions from imported aluminum products.

[0039] The beneficial effects of the present invention are:

[0040] The present invention uses a bottom-up statistical method to accurately quantify the greenhouse gas and multi-media pollutant emission levels of point sources in different process steps. It uses aluminum as the basic element flow and combines the carbon pollution emissions of different processes in the whole process to form an aluminum-carbon-pollution coupling flow spatial evaluation model, which can track the input and output of the upstream and downstream of the industrial chain and establish spatial transfer models of carbon pollution emissions at different scales, supporting the fine division of carbon pollution reduction responsibilities from the country-province-city-park-enterprise. Tracking the flow of carbon pollution emissions in different processes from the perspective of the entire life cycle, focusing on the emissions driven by spatial transfer, and establishing a spatial transfer model of energy and raw materials, making the analysis more rigorous and comprehensive, and realizing real-time monitoring of carbon pollution emissions. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0042] Figure 2 Schematic diagram of the spatialization of aluminum-carbon-pollution coupled flow and the multi-media carbon pollution environment trend. DETAILED DESCRIPTION

[0043] The present invention proposes a multi-scale cross-medium carbon-pollution coupled flow modeling method based on process nodes, which is further described below in conjunction with the accompanying drawings and specific embodiments.

[0044] Figure 1 This is a schematic diagram of the multi-scale cross-media carbon-pollution coupling flow modeling method based on process nodes of the present invention. Because the existing technology lacks the exploration of corresponding carbon emissions from the perspective of the entire life cycle, that is, it generally explores the direct carbon emissions caused by electrolytic aluminum smelting in the key link, resulting in an underestimation of the carbon emissions per ton of aluminum produced. In addition, because the existing technology fails to fully consider the pollutant emissions caused by the consumption of energy and electricity in the production of aluminum, it is bound to seriously underestimate the environmental problems caused by the production of aluminum.

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

[0046] 1. Establish aluminum element flow model and carbon pollution coupled emission flow model in long-process and short-process production processes. Based on the energy material metabolism of long-process and short-process aluminum production processes, track aluminum element flow and carbon pollution emissions in the whole process. The long process includes bauxite mining, bauxite smelting, electrolytic alumina, primary aluminum processing and terminal product production. The main energy inputs include coal, oil, natural gas, electricity, etc., and auxiliary material inputs include carbon anode, calcium carbonate and sodium hydroxide, etc., including: Use formula (1) to construct the aluminum element flow model for the whole life cycle, and use formula (3-14) to construct the greenhouse gas (CO 2 eq) and pollutants (NOx, SO 2 ,PM 2.5 The short-process production process includes the pretreatment, smelting and processing of aluminum scrap to obtain recycled aluminum. The main energy inputs include coal, electricity, etc., and the raw material inputs include scrap aluminum. Formula (2) is used to construct the short-process aluminum element flow model. The carbon dioxide (CO 2 ) and pollutants (NOx, SO 2 ,PM 2.5 and Hg) emissions, the aluminum industry chain is divided into two links: aluminum waste pretreatment and recycled aluminum smelting. The CO2 emissions of each process in the short process are calculated by formula (15). 2 Direct emissions (energy consumption) and indirect emissions (electricity) are calculated using the same long-process pollutant emission formula (11-14).

[0047]

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

[0049] In the formula, Al Input is the total amount of aluminum input in the long-process production process; I Al,pro and I Al,imp are the mining and import volumes of bauxite; C Al,p is the percentage of aluminum contained in aluminum resources (bauxite, alumina, aluminum ingot); Al,loss and O Al,exp are the loss and export volume of aluminum resources in each life cycle; L Al,p is the percentage of aluminum resources lost in process p; Al Input-rec is the total amount of aluminum input in the short-process production process; I Al,EOF is the amount of aluminum-containing waste recycled; C Al,Rec It is the percentage of aluminum contained in the recycled scrap.

[0050]

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

[0052] In the formula, E CO2eq is the total carbon dioxide equivalent emission in the long process, E Fuel,CO2eq , E Material,CO2eq , E Electricity,CO2eq and E Limestone,CO2eq are fuel consumption, carbon anode reduction, electricity use and carbon dioxide emissions from calcium carbonate decomposition; F f,p is the consumption of fuel f in process p; NCV f is the average lower calorific value of the fuel f (coal, oil, natural gas) (GJ / t and GJ / 10,000 Nm 3 );C f,C is the carbon content per unit calorific 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 electricity used in province r; EF anode is the carbon dioxide emission factor consumed by the carbon anode (tCO 2 / t-Al); N Al is the annual primary aluminum production (t); L is the consumption of limestone; EF limestone is the emission factor for burning limestone (tCO 2 / t-Al);NC anode is the net consumption of aluminum carbon anode per ton in the year (0.42tC / t-Al); S anode is the average sulfur content of carbon anode in the year (2%); A anode It is the average ash content of carbon anode in the year (0.4%).

[0053] E CO2,eq,t =EF t ×N Al (9)

[0054]

[0055] Where t represents the gas N 2 O,CF 4 ,C 2 F 6 , E CO2,eq,t Represents gas N 2 O,CF 4 ,C 2 F 6 Emissions; EFt N 2 O,CF 4 and C 2 F 6 The emission factors of gases are 3.318 kg N 2 O / t-Al, 0.034kg CF 4 / t-Al and 0.0034kg C 2 F 6 / t-Al; GWP CF4 and GWP C2F6 For CF 4 and C 2 F 6 The global warming potential (GWP) of the gas is 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 They are respectively SO in the long process step p 2 ,Hg,PM 2.5 , NOx emissions; C f,S and C f,Hg are the S content and Hg content in fuel f respectively; R SO2 ,R Hg ,R PM2.5 ,R NOx They are SO under different control measures. 2 ,Hg,PM 2.5 ,NOx removal efficiency;Power p For EI r,SO2 ,EI r,Hg ,EI r,PM2.5,EI r,NOx They represent the SO of electricity used in the production of process p in province r. 2 ,Hg,PM 2.5 , NOx emission intensity; a is the sulfur retention rate in the ash (%); b is the ash content released (%); EF p,PM2.5 is 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 CO in the short process 2 Emissions; F f,rec is the fuel usage in the short process; Power rec It is the amount of electricity used in the short process.

[0063] 2. Establish a spatial transfer model at the provincial and national scales. Obtain the transfer of carbon pollution emissions driven by raw materials and energy in the production process at the provincial and national scales. The transactions involve coal, electricity, bauxite, alumina, and aluminum ingots. Use the bulk commodity logistics network to establish a spatial transfer matrix including aluminum resources (bauxite, alumina, and aluminum ingots), a coal transfer matrix, and an electricity transfer matrix. Based on the real-time acquisition of factory production data and the previously compiled aluminum-carbon-pollution database at the national, provincial, and enterprise levels, a spatial transfer matrix of aluminum-coal-electricity in the production process is established. The carbon pollution emission model for the spatial transfer of energy and raw materials at the provincial scale includes: aluminum resource transmission matrix, including input and output provinces and corresponding transportation volumes; coal transmission matrix, including input and output provinces, coal transportation volume, and transportation methods (railway, highway, and combined water and land transport); electricity transmission matrix, including input and output provinces, and electricity transmission volume. Combine the transmission matrix of raw materials and energy with the transportation emission factor to establish a spatial transfer model of carbon pollution emissions from the output to the input based on the process in the whole life cycle, using formulas (16-17). For the aluminum resource output area, the energy consumption level of the mining process is also considered, using formulas (18-19). Through the national-scale aluminum resource spatial transfer database, the corresponding aluminum resource input and output are identified, and the aluminum resource spatial transfer matrix and the transportation process emission factor are used to calculate the cumulative reduction of CO2 in the aluminum resource input area using formula (20). 2 eq transfer emission.

[0064] VE i,j =EI j ×TB i,j (16)

[0065] EI j =E j×P j (17)

[0066] Where VE is the spatial transfer emission from raw material energy exporting province j to raw material energy importing province i; EI j is the emission intensity of raw material energy exporting province j; TB i,j E is the amount of raw materials and energy that input province i imports from output province j; j CO2 produced per unit of raw materials and energy for province j 2 eq,PM 2.5 ,SO 2 , NOx and Hg emissions; P j is 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 It is the CO2 emitted by China in the process of exporting aluminum-containing products. 2 eq total emissions, n represents different locations; E Al and E Tran They are CO from the production and transportation of aluminum-containing products. 2 eq emission; W d is the transport volume of aluminum-containing products, t; D c is the distance of conveying aluminum-containing products to c, NM; EEOI c is the energy efficiency index delivered to different locations c, GCO 2 / t / NM.

[0070]

[0071] In the formula, E i It is the CO2 produced by China in the process of importing aluminum-containing products. 2 eq total emission; E Al and E Tran They are the CO2 emissions from the production and transportation of aluminum-containing products in locations other than China. 2 eq emission.

[0072] 3: Establish a multi-media emission factor model. Figure 2The figure is a schematic diagram of the spatialization of aluminum-carbon-pollution coupling flow and the environmental fate of multi-media carbon pollution. The spatial evaluation and monitoring technology of aluminum-carbon-pollution coupling flow is developed, which incorporates the resource utilization of solid waste and tracks the environmental fate of greenhouse gases and multi-media pollutants. The method is designed as a comprehensive system model of the entire life cycle of the aluminum industry chain based on material flow, energy flow and emission flow. It can not only be used for the multi-media carbon pollution emissions of a single aluminum production plant within the accounting boundary, but also for analyzing the multi-media carbon pollution emissions and the division of emission reduction responsibilities at different spatial scales. On the basis of establishing a multi-scale aluminum industry atmospheric carbon pollution emission system model, the resource utilization method of solid waste in 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, waste recycling can be achieved through different means. For example, red mud can be used in synergistic applications with major industries such as steel, chemical industry, materials and environmental protection by utilizing its different chemical composition. Formula (22) is used to quantify the amount of solid waste resources utilized by 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] Where P waste,p,k is the amount of solid waste k generated during process p, t; P Al is the production volume of aluminum-containing products, t; a waste,p,k is the coefficient of solid waste k generated by the production unit of aluminum-containing products in process p, and the red mud coefficient is 1.0-1.8; the aluminum ash slag in primary aluminum casting, aluminum product processing and aluminum alloy regeneration is 6-8kg, 20-50kg and 80-100kg respectively, the overhaul slag is 20-30kg, and the anode carbon slag is 8-12kg; R recycle is the total amount of solid waste resource utilization, R mud , R SPL , R dross and R anode They are the solid resource utilization of red mud, overhaul slag, aluminum ash slag and anode carbon slag.

[0076] Fourth: Comprehensive aluminum element flow model, carbon pollution coupling emission flow model, spatial transfer model, and multi-media emission factor model, and establish a multi-scale cross-media carbon pollution coupling flow model based on process nodes. Gaseous medium carbon pollution emissions include production and spatial transfer. Production stage emissions include bauxite mining, bauxite refining, alumina smelting, primary aluminum processing and waste aluminum recycling emissions. Spatial transfer emissions include transfer emissions during the spatial transfer of coal and electricity; transportation stage emissions include transfer emissions during the process of China's input and output of aluminum resources. Based on the multidimensional material flow model, a multi-scale cross-media carbon pollution coupling flow model based on process nodes is established as shown in formula (23), where g represents CO 2 eq, NOx, SO 2 ,PM 2.5 Identify emissions from the multi-media full life cycle aluminum industry chain and provide 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 is the total carbon pollution emission in the long process, E g,mining is the carbon emission during bauxite mining, E g,refining E is the carbon pollution emission in the process of bauxite smelting; g,smelting E is the carbon pollution emission in the alumina refining process; g,manufacuring Carbon emissions during semi-processing and processing of aluminum ingots; E g,recycling E is the carbon pollution emission during the recycling process of aluminum products; g,exprorting Cumulative carbon emissions for exported 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 implementation case builds a model for the aluminum-carbon-pollution coupled flow and multi-media emissions in 2020. Construct a China aluminum-carbon-pollution coupled flow model in 2020 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. Statistics on the fuel consumption, electricity use and auxiliary material consumption of the aluminum industry from bauxite mining to the production of aluminum semi-finished products, and establish the plant-level point source full life cycle carbon dioxide equivalent (CO 2 eq) and pollutants (PM 2.5 、NOx、SO 2and Hg). The aluminum element flow model identifies that in 2020, China's total aluminum input was 49,150 kt, of which 22,300 kt of bauxite came from primary mining and 26,850 kt came from direct input. The multi-media emission factor model shows that in 2020, after smelting bauxite, electrolytic alumina, and processing of raw aluminum, 76.5% eventually entered the terminal product, and 23.5% was lost to the environment or entered the comprehensive utilization link with tailings, red mud, and waste slag. In the terminal consumption link, due to the spatial transfer of aluminum products, about 25% of the aluminum products produced, such as transportation, 35% of electronic appliances, 15% of packaging materials, and 25% of durable goods, are output with the spatial transfer matrix, and the remaining aluminum products continue to flow between provinces. After the reuse of consumer products is scrapped, 19.4% adopts the short-process aluminum smelting process to enter the recycling and reuse link. In 2020, China's aluminum plants emitted a total of 380 MtCO 2 eq, 277kt SO 2 , 5,552kg Hg, 491kt NOx and 389kt PM 2.5 The electrolytic alumina process contributes about 66% of the share, mainly from coal combustion and carbon anode reduction process.

[0080] The atmospheric carbon emissions in this implementation case include CO 2 and NOx, SO 2 ,PM 2.5 and Hg emissions, solid waste emissions include red mud, overhaul slag, aluminum ash slag and anode carbon slag, and water pollution emissions include COB, BOD, nitrogen oxides, etc. Based on the coupled flow model of aluminum-carbon-pollutant material flow, the carbon pollution emissions of the aluminum industry chain throughout the life cycle and the resource utilization of solid wastes in multi-media emissions are analyzed, focusing on emissions driven by spatial transfer, making the analysis more rigorous and comprehensive, and realizing real-time monitoring of carbon pollution emissions.

Claims

1. A multi-scale cross-media carbon-pollution coupling flow modeling method based on process nodes, characterized in that: include: Based on the energy and material metabolism of the long and short processes in the aluminum production process, the aluminum element flow model and the carbon-pollution coupled emission flow model in the long and short process production processes are established; Based on the use of raw materials and energy in the production process, the CO2eq transfer emissions are calculated, and a spatial transfer model at the provincial and national scales is established; Based on multi-scale greenhouse gas emissions and multi-media pollutant emissions data, 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; By 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 model based on process nodes is established.

2. According to the multi-scale cross-media carbon-pollution coupling flow modeling method based on process nodes in claim 1, it is characterized in that: The aluminum element flow model is: <h2 style=";text-align:left;direction:ltr">Al<h2 style=";text-align:left;direction:ltr"> Input-rec <h2 style=";text-align:left;direction:ltr"> =∑(I<h2 style=";text-align:left;direction:ltr"> Al,EOF <h2 style=";text-align:left;direction:ltr"> ×C<h2 style=";text-align:left;direction:ltr"> Al,Rec <h2 style=";text-align:left;direction:ltr"> ) (2) In the formula, Al Input is the total input of aluminum element in the long process production process; I Al,pro and I Al,imp are the mining and input of bauxite respectively; C Al,p is the aluminum content percentage of the aluminum resource; Al,loss and O Al,exp are the loss and output of aluminum resources in each life cycle; L Al,p is the percentage of aluminum resources lost in process p; Al Input-rec is the total amount of aluminum input in the short-process production process; I Al,EOF is the amount of aluminum-containing waste recycled; C Al,Rec It is the percentage of aluminum contained in the recycled waste.

3. The multi-scale cross-media carbon-pollution coupling flow modeling method based on process nodes according to claim 1 or 2 is characterized in that: The carbon-pollution coupled emission flow model is: EF anode =NC anode ×(1-S anode -A anode )×44 / 12 (8) E CO2,eq,t =EF t ×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) In the formula, E CO2eq is the total carbon dioxide equivalent emission in the long process, E Fuel,CO2eq , E Material,CO2eq , E Electricity,CO2eq and E Limestone,CO2eq are fuel consumption, carbon anode reduction, electricity use and carbon dioxide emissions from calcium carbonate decomposition; 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 calorific 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 electricity used in province r; EF anode is the carbon dioxide emission factor consumed by the carbon anode, tCO2 / t-Al; N Al is the annual production of primary aluminum, t; L is the consumption of limestone, t; EF limestone is the emission factor for burning limestone, tCO2 / t-Al; NC anode The net consumption of aluminum carbon anode in a year is 0.42tC / t-Al; S anode is the average sulfur content of carbon anode in the year, 2%; A anode is the average ash content of carbon anode in the year, 0.4%; t represents the gases N2O, CF4, C2F6, E CO2,eq,t Respectively represent the emissions of gases N2O, CF4, and C2F6; EF t The emission factors of N2O, CF4 and C2F6 gases are 3.318kg N2O / t-Al, 0.034kg CF4 / t-Al and 0.0034kg C2F6 / t-Al respectively; GWP CF4 and GWP C2F6 is the global warming potential, GWP, of CF4 and C2F6, with values ​​of 6500 and 9200; E SO2,p ,E Hg,p ,E PM2.5,p and E NOx,p They are SO2, Hg, and PM in the long process step p. 2.5 , NOx emissions; C f,S and C f,Hg are respectively the S content and Hg content in fuel f, %; R SO2 ,R Hg ,R PM2.5 ,R NOx SO2, Hg, PM under different control measures 2.5 ,NOx removal efficiency, %; Power p For EI r,SO2 ,EI r,Hg ,EI r,PM2.5 ,EI r,NOx They represent the production of SO2, Hg, and PM using electricity in process p in province r. 2.5 , NOx emission intensity; 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 in process p; E CO2,rec is the total CO2 emission in the short process; F f,rec is the fuel usage in the short process; Power rec It is the amount of electricity used in the short process.

4. According to the multi-scale cross-media carbon-pollution coupling flow modeling method based on process nodes in claim 1, it is characterized in that: The spatial transfer model is: AND i,j =EI j ×TB i,j (16) HEY j =And j ×P j (17) Where VE is the spatial transfer emissions from raw material and energy exporting province j to raw material and energy importing province i; EI j is the emission intensity of raw material energy exporting province j; TB i,j E is the amount of raw materials and energy that input province i imports from output province j; j is the CO2eq,PM of unit raw material or energy produced in province j 2.5 , SO2, NOx and Hg emissions; P j is the raw material and energy production of province j.

5. The multi-scale cross-media carbon-pollution coupling flow modeling method based on process nodes according to claim 1 or 4, characterized in that: The calculation formula for the transfer emissions of CO2eq is as follows: HAVE BEEN Tran =W d ×D c ×NOW c (19) In the formula, E e is the total CO2eq emissions from China’s export of aluminum-containing products, where n represents different locations; E Al and E Tran They are CO2eq emissions from the production and transportation of aluminum-containing products; W d is the transport volume of aluminum-containing products, t; D c is the distance of conveying aluminum-containing products to c, NM; EEOI c is the energy efficiency index of transport to different locations c, GCO2 / t / NM; E i is the total CO2eq emissions from China’s import of aluminum-containing products; E Al and E Tran They are the CO2eq emissions from the production and transportation of aluminum-containing products in locations other than China.

6. The multi-scale cross-media carbon-pollution coupling flow modeling method based on process nodes according to claim 1 is characterized in that: The multi-media emission factor model is: P waste,p,k =P Al ×a waste,p,k (21) R recycle =R mud +R SPL +R dross +R anode (22) Where P waste,p,k is the amount of solid waste k generated during process p, t; P Al is the production volume of aluminum-containing products, t; a waste,p,k is the coefficient of solid waste k generated by the production unit of aluminum-containing products in process p, and the red mud coefficient is 1.0-1.8; the aluminum ash slag in primary aluminum casting, aluminum product processing and aluminum alloy regeneration is 6-8kg, 20-50kg and 80-100kg respectively, the overhaul slag is 20-30kg, and the anode carbon slag is 8-12kg; R recycle is the total amount of solid waste resource utilization, R mud , R SPL , R dross and R anode They are the solid resource utilization of red mud, overhaul slag, aluminum ash slag and anode carbon slag.

7. The multi-scale cross-media carbon-pollution coupling flow modeling method based on process nodes according to patent claim 1 is characterized in that: The multi-scale cross-media carbon pollution coupling flow model based on process nodes is: AND g =And g,mining +E g,refining +E g,smelting +E g,manufacturing +E g,recycling +E g,exporting -AND g,importing (23) In the formula, E g is the total carbon pollution emission in the long process, E g,mining is the carbon emission during bauxite mining, E g,refining E is the carbon pollution emission in the process of bauxite smelting; g,smelting E is the carbon pollution emission in the alumina refining process; g,manufacuring Carbon emissions during semi-processing and processing of aluminum ingots; E g,recycling E is the carbon pollution emission during the recycling process of aluminum products; g,exprorting The accumulated carbon emissions from exported aluminum products; g,importing Reduce carbon emissions from imported aluminum products.

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