How big is the pressure on carbon emissions in the chemical industry?

2.2 Prominent emission intensity

Although from the national dimension, the total carbon emission contribution of the chemical industry is not large, but at the regional level, due to the difference in regional economic structure, energy structure and development level, it still faces differential pressure. In particular, Inner Mongolia, a large coal province, was criticized in February by the National Development and Reform Commission for failing to complete the "dual control" assessment of total energy consumption and intensity. Based on the above-scale income and energy consumption of industry and its subdivision chemical industry in the statistical yearbook of some provinces and cities, we simply calculated the energy consumption and carbon emissions corresponding to each 10,000 yuan income.

The carbon emissions per unit of energy consumption were calculated by using the consumption ratio of coal, crude oil and natural gas in each province and city to establish the conversion from energy consumption data to carbon emissions. Based on the newly released indicators of energy consumption reduction rate per 10,000 yuan of regional GDP by province (autonomous region and city), we selected the three worst-performing provinces and cities (Inner Mongolia, Ningxia and Liaoning) and the three best-performing provinces and cities (Beijing, Hebei and Gansu), and compared them with the national estimated data. First, from the perspective of unit emissions of the industry, the carbon emissions per unit income of the chemical industry are higher than the average level of the industrial industry. Secondly, in terms of regional differences, for provinces and cities with poor performance of 10,000 yuan energy consumption index, the carbon emission cost per unit income is also significantly higher. Therefore, from the perspective of emission intensity, the chemical industry still faces certain challenges in emission reduction, and the regional differences are very obvious.

2.3 Carbon emission measurement methods of chemical products

In general, the chemical industry emissions have the characteristics of limited total amount but outstanding intensity. And because of the wide range of products in the chemical industry, clearing the core processes that generate carbon emissions is important to identify future risks and opportunities. The first step is to identify the sources and accounting methods of carbon emissions in the chemical industry. The establishment of our carbon emission inventory is based on algorithms rather than online monitoring and is consistent with the international standards of the IPCC. According to China's official carbon emission accounting guidelines, the sources of carbon emissions in chemical production can be mainly subdivided into five aspects, which are fuel combustion emissions, exhaust gas flare combustion emissions, industrial production process emissions, CO2 recovery and utilization, and CO2 emissions implicit in net purchased electricity and heat. In this paper, emissions from fuel combustion and implicit emissions from net purchased electricity and heat are classified as emissions from public works, emissions from industrial production processes are listed separately, and emissions from flare combustion of waste gas and CO2 recovery and utilization (except synthetic urea consumption) are not considered.

2.3.1 Discharge from utility projects

The utility project emissions of chemical enterprises are mainly energy-related emissions. Energy consumption in the production process can be primary energy and secondary energy sources. Different fuels emit different amounts of carbon during combustion. Electricity is a secondary energy, but because the process of generating electricity still requires the fuel combustion of the power plant, in the accounting guide, electricity also has a carbon emission coefficient, in this paper we use the Beijing 2020 new standard 0.604 tons of CO2/MWh calculation. Generally, we refer to fuel combustion emissions, electric/thermal implied carbon emissions and torch combustion emissions as utility emissions. In this paper, we focus on the calculation of fuel combustion and electric/thermal implied carbon emissions.

2.3.2 Emissions from industrial processes

The calculation of process carbon emissions is based on the principle of conservation of material mass. The 2006 IPCC Guidelines for National Greenhouse Gas Inventories assume that all the C element lost in process emissions is converted into CO2 emission. The carbon content difference between raw materials and products (including secondary products) is the CO2 emission during the production of the product. Process emissions and utility emissions together make up all carbon emissions from chemical preparation.

In addition, since overseas oil and gas routes are mainly used, the process is mature and there are complete process emission data, so we can directly use the IPCC and EU published oil and gas route emission factors to directly calculate. For important coal chemical routes in China, we will supplement the more detailed carbon emission calculation process.