Chemical industry development in the context of carbon neutrality

1. What is carbon neutral

1.1. Carbon neutrality has become a global trend, and most of the world's major economies have put forward carbon neutrality targets

Carbon emission is an issue of global concern. The IPCC report on Global Warming 1.5 ° C points out that climate change will be a major challenge to human society, and implementing carbon neutrality strategies is an important measure to actively respond to the challenge.

In simple terms, "carbon neutrality" is defined as the offset between the CO2 emissions caused by human activities and the CO2 removal caused by human activities over a certain period of time. Carbon neutrality is a system balance process, emphasizing the overall balance; At the same time, carbon neutrality is a dynamic equilibrium process, in which the total amount of emissions and the total amount of absorption remain in balance over a period of time.

From a global perspective, countries have reached a consensus on climate issues and jointly signed the Paris Agreement, establishing an institutional framework for post-2020 global climate governance. In December 2015, nearly 200 parties to the United Nations Framework Convention on Climate Change reached the Paris Agreement at the Paris Climate Change Conference, which set the goal of "controlling the global temperature rise to less than two degrees Celsius" and strive to limit the temperature rise to less than 1.5 degrees Celsius.

Carbon neutrality has become a global trend, and major overseas economies have announced carbon neutrality targets one after another. According to the disclosure of the United Nations Framework Convention on Climate Change, as of September 2021, 164 countries have submitted their nationally determined contribution plans, most of which set 2050 as the target year for carbon neutrality, and promote their work in various ways such as legislation and promulgation of policies.

1.2. China is actively responding to the challenge of carbon reduction and has set the goal of carbon neutrality by 2060

After joining the WTO in 2001, China's CO2 emissions have experienced a period of high growth for 10 years, and China's carbon emissions in 2020 are the highest in the world. Before joining the WTO, China's carbon emissions were in a slow change stage, and the annual carbon emissions were roughly 3 billion tons. Ten years after China's accession to the WTO, the rapid development of China's economy, accompanied by the rapid growth of CO2 emissions, carbon emissions at this stage increased to about 9.5 billion tons/year. In 2020, China's carbon emissions accounted for about 31% of the global total, and the second largest United States accounted for 14%. In recent years, the state has intensified regulation and control in energy consumption, environmental protection and other aspects, and the growth trend of carbon emissions has been effectively controlled. Since 2013, China's carbon emissions have remained below 10 billion tons per year.

1.3. China's carbon peak carbon neutral "1+N" policy system promotes the realization of the dual carbon goal

A series of documents will build a carbon peak carbon neutral "1+N" policy system with clear goals, reasonable division of labor, strong measures and orderly connection. The "Opinions of the Central Committee of the Communist Party of China and The State Council on Fully, Accurately and Comprehensively Implementing the New Development Concept to achieve carbon Peak Carbon Neutrality" (hereinafter referred to as the "Opinions"), as "1", plays a leading role in the "1+N" policy system of carbon peak carbon neutrality, and will jointly constitute the top-level design through the two stages of carbon peak and carbon neutrality before 2030. "N" includes carbon peaking implementation plans in energy, industry, transportation, urban and rural construction and other sub-sectors, as well as scientific and technological support, energy security, carbon sink capacity, financial and financial price policies, standard measurement systems, inspection and assessment and other security plans, the future carbon peaking implementation plans in various fields will be introduced one after another.

The "Opinions" put forward five main goals: building a green, low-carbon and circular development economic system, improving energy utilization efficiency, increasing the proportion of non-fossil energy consumption, reducing carbon dioxide emission levels, and improving the carbon sink capacity of the ecosystem. It is realized that carbon peaking and carbon neutrality is a multidimensional, three-dimensional and systematic project involving all aspects of economic and social development. The Opinions put forward 31 key tasks and clarified the road map and construction drawing of carbon peaking and carbon neutrality work.

The "Action Plan for achieving Carbon Peak before 2030" is the first policy document in "N", which focuses more on the goal of achieving carbon peak before 2030, and the relevant indicators and tasks are more detailed, concrete and concrete. The "Plan" focuses on ten actions to reach the peak of carbon, and makes deployment in ten aspects, such as energy, energy conservation, industry, urban and rural construction, transportation, circular economy, scientific and technological innovation, carbon sink, national action, and pilot construction, and plans a series of action goals.

1.4. Analysis of China's carbon peak emission reduction path and contribution degree in 2030

The "Opinions" put forward clear targets in terms of energy intensity per unit of GDP, carbon dioxide emission intensity per unit of GDP, forest stock, etc., which provides a basis for the calculation of emission reduction contribution of different emission reduction paths. According to the comprehensive report of the "Research on China's Long-term Low-carbon Development Strategy and Transformation Path" project, if the carbon peak target of 2030 is successfully achieved, China's total carbon emissions will peak at 10.473 billion tons, which is still 4.42% more than the total carbon emissions in 2020. In 2030, the reduction of carbon emissions due to the reduction of energy intensity per unit of GDP will be 17.450 million tons, and the reduction of carbon emissions due to the reduction of carbon intensity per unit of energy consumption will be 5.103 million tons, accounting for 76% and 22% respectively. The contribution of energy consumption reduction in the peaking process is higher than that of carbon emission reduction caused by the adjustment of energy structure. (Note: This reduction does not represent an actual reduction in CO2 emissions, but rather the difference between theoretical carbon emissions under uncapped conditions.)

2. Carbon emission of China's chemical industry: emission intensity is concerned

2.1. The total carbon emission of the chemical industry is not high, but the carbon emission intensity per unit GDP is high

Carbon emissions from the chemical industry are not high and have decreased significantly since 2015. According to CEADs statistics, in 2019, the carbon emissions of China's petroleum processing and coking industries, chemical raw materials and chemical products industries were 172 million tons and 164 million tons, respectively, and the emissions of chemical fiber manufacturing, rubber products and plastic products industries were smaller. In addition to the power Department, although the carbon emissions of China's petroleum processing and coking industry, chemical raw materials and chemical products industry ranked top in 2019, the emissions of the top 3 were much higher than the carbon emissions of the chemical industry.

From 1997 to 2019, the highest carbon emission of China's chemical industry was in 2015, which was 464 million tons, and in 2019, it was 341 million tons, down 26.4% compared with 2015. The peak of carbon emissions from the chemical industry has passed, and emissions in 2019 have fallen to 2008 levels.

Industry structure characteristics are different from China, the chemical industry in the United States accounted for a higher proportion of carbon emissions, and declined from 2018 to 2020. According to the United States "Greenhouse Gas Reporting Project (GHGRP)" data, in addition to the Ministry of power, the chemical industry in the United States in 2020 carbon emissions accounted for 16.6%, although the proportion is higher than China, but the total amount is smaller than China. Emissions from the US chemical industry peaked at 191 million tonnes in 2018 and have declined each year since, reaching 180 million tonnes in 2020.

The emission intensity of each sub-industry in the chemical industry is at a medium and high level. In 2017, the carbon emission intensity of China's petroleum processing and coking industry, chemical raw materials and products manufacturing industry, and chemical fiber manufacturing industry was 0.51 tons/million yuan, 0.18 tons/million yuan, and 0.05 tons/million yuan, respectively, ranking 6th, 10th and 17th among 33 industries except the power Department. According to the classification of Ping Xinqiao et al., industries with carbon emission intensity lower than 0.05 tons / 10,000 yuan, between 0.05 tons / 10,000 yuan and 0.5 tons / 10,000 yuan, and higher than 0.5 tons / 10,000 yuan are classified as "light emission industries", "medium emission industries" and "heavy emission industries". The chemical fiber manufacturing industry, chemical raw materials and products manufacturing industry is in the medium emission industry, and the petroleum processing and coking industry is in the rearrangement and release industry.

2.2. Introduction to accounting methods for greenhouse gas emissions of enterprises

Enterprises are the main body of carbon emissions. From the enterprise level, after determining the emission inventory boundary, the following steps are generally taken to calculate GHG emissions: identify GHG emission sources, select GHG emission calculation methods, collect activity data and select emission factors, apply calculation tools, and summarize GHG emission data to the enterprise level.

The first step is to determine the emission source, which can be subdivided into reaction units and specific equipment.

Taking the manufacturing of chemical raw materials and chemical products as an example, the main emission units of general enterprises, synthetic ammonia or methanol enterprises in the industry include: main equipment, synthetic ammonia equipment, methanol equipment, CO2 utilization equipment (such as soda ash equipment, etc.), other public and supporting projects; Direct emission sources mainly include: steam reforming equipment such as coal or natural gas (that is, synthetic gas preparation equipment), synthetic gas conversion equipment, downstream use of CO2 production equipment (such as carbonization tower, falling film evaporator, etc.), steam boilers, power station boiler, fire moment, own vehicles, etc.; Indirect sources of emissions mainly include: equipment that uses outsourced electricity and heat.

The second step is to choose the calculation method of greenhouse gas emissions, the international accounting standards have been issued, and the domestic industry accounting standards have been introduced, which can be divided into two categories: emissions from public works and emissions from industrial processes. For a breakdown, the reporting subject's total greenhouse gas (GHG) emissions should equal the CO2 emissions from fuel combustion, plus the CO2 emissions from exhaust gas flare combustion, plus the CO2 emissions from industrial processes, minus the amount of CO2 recovered by the enterprise, plus the CO2 emissions implied by the net purchase of electricity and heat by the enterprise. (Report source: Future Think Tank)

The third step is to collect activity data and select emission factors, which can be measured by enterprises or recommended parameters. Generally speaking, data such as fuel consumption, raw material input, and product output can be obtained through the daily operation records of enterprises, and data such as carbon content and carbon oxidation rate of related substances can be determined according to national standards or recommended values.

Companies can then use calculation tools to calculate carbon emissions and finally aggregate emissions data. The three tables attached below are reference values that may be used in the calculation process, and the calculation of chemical carbon emissions in this paper will be based on the following data.

2.3. What are the differences in carbon emission intensity of different chemical products

Different chemical products have different carbon emission characteristics and may face different regulatory environments in the future. Based on the data provided by national standards and greenhouse gas accounting and reporting system, we sorted out and analyzed the carbon emissions of various chemicals in both public works and industrial processes, and refined the energy efficiency analysis of chemical products. We found that the proportion of carbon emissions from industrial processes of chemical products in the total emissions is higher than that of general industries, but the proportion of carbon emissions from public projects and industrial processes of different chemical products is different, and the emission intensity of coal chemical products is higher. In the analysis of coal-to-methanol, a typical chemical product, we calculated that the carbon emission of the industrial process is not far from the national standard, and is less than the theoretical carbon emission value.

2.3.1. The proportion of carbon emissions in the overall industrial process of the national economy is not high, but the chemical industry accounts for a relatively high proportion

China's industrial process emissions account for a relatively small proportion of the total emissions, and carbon emissions are stable in recent years. China's energy consumption is dominated by coal, which accounted for 75% of energy consumption in 2019, and industrial processes accounted for a relatively small share of carbon emissions, accounting for about 7%, and reached a peak around 2014, with emissions of about 680 million tons in 2019.

Different from the overall situation in China, the proportion of carbon emissions in China's chemical products industrial process is almost higher than 7%. According to the "Energy Efficiency Benchmark Level and Benchmark Level in Key Areas of High Energy Consumption Industries (2021 edition)" and the national standard of energy consumption quota, we sorted out the carbon emission standards of public works for typical chemical products; At the same time, according to the 2006 IPCC National Greenhouse Gas Inventory Guide and other corporate carbon emission accounting and reporting guidelines, we sorted out the industrial process emission standards of typical chemical products. Compared with the overall industrial process carbon emissions of the national economy, the proportion of carbon emissions from the industrial process of chemical products is generally higher, and the highest is nearly 97%.

2.3.2. Carbon emission intensity distribution of typical chemical products

By examining the carbon emissions of chemical products from public projects and industrial processes, all chemical products can be divided into four types to analyze the energy efficiency level of different chemical products.

From the perspective of carbon emissions per unit output, we sorted out and analyzed the carbon emissions per unit output of public works and industrial processes of more than ten chemical products, and divided them into four quadrants based on the average carbon emissions per unit output. Among them, coal-to-olefin and carbon black are in the high carbon emissions per unit output of public works and high carbon emissions per unit output of industrial processes, and have the highest carbon emissions per unit output of all chemical products. Other coal chemical products such as coal to ethylene glycol, coal to natural gas, coal to DME, etc., have higher carbon emissions per unit output in industrial processes; Synthetic ammonia, titanium dioxide, calcium carbide, etc. have higher carbon emissions per unit output in public works. In addition, the carbon emissions per unit output of chemical products such as nitric acid, soda ash and propylene oxide are relatively low.

In terms of carbon emissions per unit income, coal chemical products such as coal-to-methanol, coal-to-dimethyl ether, coal-to-natural gas, and synthetic ammonia have the highest carbon emissions per unit income. The industrial processes of coal to ethylene glycol and nitric acid have higher carbon emission per unit income. Carbon black, calcium carbide, alumina and soda ash have higher carbon emission per unit income. Titanium dioxide, propylene oxide and other products have lower carbon emissions per unit income.

From the point of view of total emission intensity, all kinds of chemical products we statistics are basically distributed along the diagonal in the figure, individual products offset larger, some chemical products with smaller output, often higher prices, thus lower carbon emissions per unit income, such as titanium dioxide; On the contrary, some chemical products with larger output tend to have lower prices and thus higher carbon emissions per unit income, such as coal to methanol. Some chemical products with higher output and higher carbon emission intensity have more room to reduce emissions in the future.

2.3.3. Taking coal to methanol as an example, the carbon emission of chemical products in the industrial process is lower than the theoretical value

Coal chemical industry is a characteristic chemical sub-industry in China. Most of methanol production uses coal as raw material, and carbon emissions are mainly generated in sulfur recovery units. Raw coal is usually fed fresh gas into the methanol synthesis unit after gasification and multiple conversion processes to produce methanol. In this process, the purification process of the conversion gas will produce carbon dioxide gas, part of which is used as a raw material to participate in the synthesis of methanol, and most of the other is discharged as an emission gas.

From the calculation of actual production projects, it can be seen that the carbon emission per unit output of the industrial process of coal-to-methanol is lower than the theoretical value calculated according to the chemical reaction formula. There are several ways to calculate the carbon emission of chemical products. One is to calculate the carbon emission theoretically according to the physical and chemical properties of the products and the chemical reaction equation. The second is to monitor material input and output in actual production projects, prepare material balance sheets and calculate carbon emissions.

The carbon emission data calculated according to molecular formula and chemical reaction formula is the theoretical emission limit, because the original materials can not be converted into products according to the ideal situation in the actual production process; Carbon may not be completely expelled as a gas; The carbon oxygenation rate of the material is not 100%.