By Wang Hongqiu, Hou Yuxuan and Fu Kaimei, PetroChina Petrochemical Research Institute

A key section of the petrochemical industry, the ethylene industry is closely related to many industries – such as deep processing of plastics, rubber products, textiles, etc. – and even the whole national economy. Scale and technologies of the ethylene industry represent development level of a nation’s petrochemical industry.

Current and future new situations of China’s ethylene industry

After more than 50 years of development, China’s ethylene industry has made great progress. 

Relatively strong competitiveness of China’s ethylene industry

China’s ethylene capacity reached 41.68 million t/a in 2021, accounting for 20% of the world’s total. Rapid growth of capacity spurred scale development of ethylene industry. In detail, average scale of steam cracking units surged from 220 000 t/a to 810 000 t/a from 2000 to 2021, and the number of 1 million ton-grade ethylene units rose to 15 at the same period. Northeast and northwest petrochemical industry bases were established. In addition, petrochemical industry clusters were formed in Circum-Bohai-Sea Region, Yangtze River Delta and Pearl River Delta. Combined ethylene capacity of Circum-Bohai-Sea Region and Hangzhou Bay took up 37.5% of the domestic total.

Low-carbon development: an inevitable trend for the ethylene industry

Ethylene equivalent consumption of China, the largest ethylene consumer in the world, amounted to 58.84 million tons (40% of the world’s total) in 2021, when the nation’s ethylene consumption per person was 42 kg, far lower than 70-90 kg in developed countries and regions like the US, Japan, Western Europe, etc. Hence huge potential of China’s ethylene market. It is forecast that China’s ethylene capacity will skyrocket nearly 100% to 80 million tons in 2030, increasing carbon emissions accordingly. Considering China’s targets to halt the rise of carbon emissions by 2030 and reach carbon neutrality by 2060, low-carbon development will be an inevitable choice for the domestic ethylene industry.

China opened a national carbon emissions trading market in July 2021, with power generation industry being the first brought into the market. Petrochemical industry may participate in the market by 2025. On June 22, 2022, the European Parliament approved the world’s first CBAM proposal (Carbon Border Adjustment Mechanism), scheduled to exert carbon tariffs on many products (e.g. cement, fertilizers, plastics, etc.) since January 1, 2023. A transitional period will come to an end at the end of 2026, and there will be no free quotas in 2032. This will impact China’s petrochemical export, which may fall 12.4% in the case of carbon tariffs of US$30/t.

In October 2021, the National Development and Reform Commission of China issued Plan to Propel Petrochemical and Chemical Industry to Save Energy and Reduce Carbon Emissions (2021-2025), requiring that petroleum-based ethylene with energy consumption reaching 590 kg standard oil/t should account for over 30% of the total capacity by 2025, when carbon emission intensity of ethylene enterprises will greatly decrease.

However, average energy consumption of petroleum-based ethylene currently fails to reach the baseline level of 640 kg standard oil/t. Hence, the document calls for: 1) accelerating elimination of idled ethylene units and units with capacity of no more than 300 000 t/a; 2) banning construction of new naphtha cracking projects with capacity of lower than 800 000 t/a; 3) propelling application of more appropriate technologies (regarding making ethylene via direct crude oil cracking, high-efficiency heat exchanger, autonomous intelligent control system, energy cascade utilization, etc.); 4) researching electric drive technologies.

Main technologies related to low-carbon development of the ethylene industry

Carbon emissions from the petrochemical and chemical industry accounted for around 8% of domestic total in 2021, and the ethylene industry was the source of 8% of the petrochemical and chemical industry’s emissions. Around 84% of domestic ethylene capacity was contributed by producers adopting steam cracking process, including three parts – cracking furnace steam cracking, cracked gas compression and distillation separation.

      To save energy and reduce carbon emissions, ethylene producers should: 1) improve thermal efficiency of cracking furnaces (by means of cracking furnace tube heat transfer enhancement technology, cracking furnace tube coating technology, etc.); 2) employ high-efficiency separation technologies and intelligent control systems; 3) realize electrification of cracking furnaces (e.g. using green electricity to heat cracking furnaces). Other measures mainly include promoting application of technology of making olefins through direct crude oil cracking; strengthening R&D on technologies to produce ethylene with methane, carbon dioxide and biomass; etc.