Toward carbon neutrality in China: A national wide carbon flow tracing and the CO emission control strategies for CO-intensive industries.

Massive emission of CO as a potential driver of climate change has become a global issue presented in front of the whole human beings. Motivated by the CO cut-down requirement, China has aggressively undertaken restrictions aiming for peaking the carbon dioxide by 2030 and achieving carbon neutrality by 2060. However, due to the complex structures of industry and fossil fuel consumption in China, specific carbon neutrality route and the CO reduction potential are still open questions. To address the bottleneck of the "dual-carbon" target, quantitative carbon transfer and emission of different sectors are traced based on mass balance model. The future CO reduction potentials are predicted based on structural path decomposition, with consideration of energy efficiency enhancement and process innovation. Electricity generation, iron & steel industry and cement industry are identified as the top three CO-intensive sectors, with CO intensity of at around 517 kg CO/MWh, 2017 kg CO/t CS and 843 kg CO/t clinker, respectively. Non-fossil power is suggested to substitute coal-fired boilers to achieve decarbonization of the electricity generation industry, which is the largest energy conversion sector in China. As two dominant energy end-users, the iron & steel industry and cement industry exhibit different CO emission sources, requiring divergent approaches for low-carbon development. For the iron & steel industry, around 89 % direct CO emission comes from fossil fuel. Immediate energy efficiency enhancements are suggested, followed by process innovations such as oxy-blast furnaces, hydrogen-based reduction, and scrap-based electric arc furnaces. For the cement industry, around 66 % of direct CO emission comes from carbonate decomposition. The process innovation with CO enrich and recovery would be the most effectiveness for carbon reduction. Staged low-carbon policies of the three CO-intensive industries are introduced at the end of this paper, which is capable of achieving 75-80 % cut down of CO emission intensity in China till 2060.