Views:0 Author:Site Editor Publish Time: 2021-11-10 Origin:Site
Recently, the National Development and Reform Commission and the State-owned Assets Supervision and Administration Commission have commissioned relevant industry associations and research institutes to conduct research on the development path of key industries such as power, building materials, and non-ferrous metals under the constraints of carbon peaking and carbon neutrality. The aluminum industry is a basic industry that develops the national economy and improves people's living standards, and it is also a major source of carbon dioxide emissions in the non-ferrous industry. All links of its entire life cycle, including bauxite mining, alumina smelting, primary aluminum electrolysis, aluminum materials, final product production and recycled aluminum recycling, and upstream energy production processes, will emit CO2. Therefore, exploring the carbon emission reduction path of the aluminum industry is crucial to achieving my country's carbon peak and carbon neutral goals.
The definition of carbon peak and carbon neutrality
According to the definition of the United Nations Intergovernmental Panel on Climate Change (IPCC), carbon peak refers to a region or industry’s annual CO2 emissions reaching historical highs and then entering a continuous decline process, which is the history of CO2 emissions from increasing to decreasing. Turning point. Carbon peak includes peak year and peak value. Carbon neutrality refers to the amount of CO2 emissions produced by human activities, which is balanced with the amount of absorption achieved by the application of CO2 removal technologies (such as afforestation).
In October 2019, the 96th meeting of the Council of the International Aluminum Association decided to set up a working group on greenhouse gas emission reduction approaches, responsible for the work of the international aluminum industry’s greenhouse gas emission reduction approaches, and initially drafted the coverage and coverage of greenhouse gas emissions in the aluminum industry. The goal and approach to zero net greenhouse gas emissions in 2050.
In March 2021, the International Aluminum Association issued the "Aluminum Industry Greenhouse Gas Emission Path in 2050", and proposed the global aluminum industry's greenhouse gas emission reduction target: by 2050, global aluminum production will be 170 million tons (of which primary aluminum production is 90 million tons). t) Under the conditions, the global aluminum industry covers the entire industrial chain (bauxite, alumina and electrolytic aluminum production, aluminum processing and manufacturing, and waste recycling and regeneration). The total emissions are 250 million tons of CO2 equivalent; Emissions from electricity consumption in aluminum production-related processes (especially the smelting process) are close to zero, with direct emissions of 200 million tons of CO2 equivalent, and fuel combustion and power consumption during the recycling and manufacturing processes emit 50 million tons of CO2 equivalent.
With reference to the international aluminum industry's greenhouse gas emission reduction targets, combined with my country's current aluminum industry CO2 emissions status, and the non-ferrous industry proposed by the China Nonferrous Metals Industry Association, strive to achieve carbon peaks by 2025 and reduce emissions by 40% by 2040. my country's aluminum industry is expected It is expected to achieve a carbon peak in 2025, with a peak value of approximately 560 million tons of CO2 equivalent.
In 2018, global aluminum production was 95 million tons, of which, primary aluminum production was 64 million tons and secondary aluminum production was 31 million tons. The global aluminum industry's CO2 emissions are 1.13 billion tons equivalent. During the same period, my country's aluminum output was 42.75 million tons, of which, primary aluminum output was 35.8 million tons, secondary aluminum output was 6.95 million tons, and my country's aluminum industry CO2 emissions were 520 million tons equivalent.
The aluminum industry includes primary aluminum production (aluminum mining, alumina production, anode production, electrolytic aluminum production), secondary aluminum, aluminum processing and product manufacturing, and other industrial chains. The CO2 emissions from primary aluminum production account for about the total CO2 emissions of the aluminum industry. 94.85%, see Figure 2.
In the production of primary aluminum, CO2 emissions from energy consumption account for a relatively large amount, reaching 77.5% (of which, CO2 emissions from electricity consumption account for about 64.3%, and CO2 emissions from thermal energy consumption account for 13.1%).
Coal and electricity account for a large proportion of my country's electrolytic aluminum production
Compared with electrolytic aluminum enterprises in Europe and the United States, my country's electrolytic aluminum industry has a higher carbon emission in the electrolysis process. The main reason is that domestic primary aluminum power energy is heavily dependent on thermal power. According to statistics, at the end of 2020, self-supplied electricity consumed by my country's electrolytic aluminum operating capacity accounted for 65.2%, and grid electricity accounted for 34.8%. Among them, all self-supplied power is thermal power, and grid power is divided according to the power generation structure of each regional power grid. According to calculations, in the energy structure of electrolytic aluminum, thermal power accounted for 88.1%, and non-fossil energy accounted for 11.9%.
The energy consumption indicators of electrolytic aluminum and alumina have limited space for a significant drop
At present, the typical production process for primary aluminum production is still cryolite-alumina molten salt electrolysis (Hall-Elut molten salt electrolysis). After more than 100 years of continuous process optimization, the potential mining of alumina and electrolytic aluminum production process indicators has approached the limit. Without disruptive production process changes, there is limited room for decline in various indicators of aluminum smelting.
Key carbon reduction technologies still have bottlenecks
In aluminum smelting production, low-temperature waste heat recovery, waste-free metallurgy, inert anodes, ultra-low energy aluminum electrolysis, carbon dioxide capture and utilization, and other zero-carbon and negative-carbon core technologies are insufficient.
Calculations show that the carbon dioxide emissions of recycled aluminum are only about 4% of the carbon dioxide emissions of primary aluminum. In 2020, global aluminum production will be 99.1 million tons, of which recycled aluminum production will be 33.8 million tons, accounting for 34.1% of global aluminum production. In the same year, my country's aluminum output was 44.48 million tons, of which secondary aluminum output was 7.4 million tons, accounting for 16.6% of domestic aluminum output. There is a big gap between my country's secondary aluminum production and the international average.
Combined with the characteristics of carbon emission in my country's aluminum industry, the path to achieve carbon peak and carbon neutrality mainly includes improving energy efficiency, industrial structure adjustment, energy structure adjustment, and zero-carbon (negative) technology development.
Energy saving and efficiency improvement, reducing carbon emission intensity
In 2005, the "Proposals of the Central Committee of the Communist Party of China on Formulating the Eleventh Five-Year Plan for National Economic and Social Development" raised resource conservation as my country's "basic national policy." In the three "Five-Year Plans" since 2006, energy-saving indicators for reducing energy consumption per unit of GDP have always been listed as one of the important binding indicators of the "Five-Year Plan". From 2006 to 2019, my country’s energy consumption per unit of GDP dropped by 42.5%, carbon dioxide emissions per unit of GDP dropped by 47.9%, and AC power consumption for electrolytic aluminum dropped from 14575 kWh/t to 13,555 kWh/t, a decrease of about 7.0%.
Multi-party calculations show that energy conservation and improvement of energy efficiency will contribute more than 70% to my country's goal of reaching the peak carbon emissions by 2030, and the contribution of renewable energy and nuclear power is close to 30%. Carbon dioxide capture and storage technology will hardly make substantial contributions to my country's achievement of the carbon peak goal by 2030.
Therefore, in order to achieve carbon peak and carbon neutrality, it is necessary to increase the promotion and application of energy-saving technologies and equipment, innovate third-party energy-saving service models such as contract energy management, and promote energy-saving technologies, energy-saving equipment, energy cascade utilization and waste heat utilization, so as to improve Implementation of energy efficiency projects; strengthen the entire process, the entire chain, and the entire element benchmarking management, conduct energy-saving diagnosis, find gaps, carry out lean management, use continuous improvement as the carrier, tap the potential of energy saving and consumption reduction, and optimize technical and economic indicators.
and resolve the excess production capacity of electrolytic aluminum, control the 45 million tons of electrolytic aluminum ceiling production capacity; increase the development of "urban mines", vigorously develop short-flow smelting processes, greatly increase the production capacity of secondary aluminum, and increase the proportion of secondary aluminum; choose coastal and hydropower The rich green energy regions carry out the layout of the aluminum industry, promote the development of industrial agglomeration, build an aluminum cluster industrial base, and reduce carbon emissions in the process of logistics transportation and metal remelting.
Optimizing the energy structure, shrinking the production capacity of electrolytic aluminum thermal power, and increasing the proportion of clean energy use are direct and effective ways to achieve carbon peaks and carbon neutrality in the aluminum industry. The main measures include:
1) Eliminate coal-fired self-supplied power plants, or replace thermal power with clean energy through replacement of power generation rights of self-provided units;
2) Carry out clean transformation of self-supplied power plants and replace coal with low-carbon or zero-carbon energy;
3) Utilize the company's factory buildings and surrounding environment to build wind and photovoltaic power stations, and cooperate with energy storage technology to achieve direct supply of clean energy;
4) Relying on hydropower and nuclear power resources, replacing electrolytic aluminum production capacity, realizing direct use of clean energy;
5) Promote low-carbon transportation and gradually introduce electric and hydrogen transportation vehicles.
Promote technological innovation and achieve breakthroughs in disruptive carbon reduction technologies
Integrate domestic scientific research institutes, establish a low-carbon and green development innovation platform for China’s non-ferrous metals industry, lay out forward-looking, strategic, and disruptive projects in areas such as energy conservation and carbon reduction, cleaner production, and clean energy, implement green technology research actions, and strive to be in aluminum The industry has achieved breakthroughs in waste-free metallurgy, ultra-low energy consumption aluminum electrolytic cells, inert anodes, and carbon dioxide capture, utilization, and storage technologies to provide technical support for green development.