Multi-Catalytic-Field Assisted Conversion of Low-Concentration CO2 in Steel Byproduct Gas for Synergistic Steel-Chemical Production

Abstract

The iron and steel industry, as a major global CO₂ emitter, urgently requires technological breakthroughs in its carbon neutrality pathway. Existing emission reduction technologies such as carbon capture, utilization and storage are economically insufficient, while the full utilization of byproduct gas may lead to energy shortages in steel enterprises. Steel byproduct gases (e.g., converter gas) have complex composition, and traditional combustion results in high emissions. In this context, the proposed low concentration CO₂ (LCC) system demonstrates dual advantages: (1) enhancing the calorific value of the byproduct gas to meet the demands of high-energy steelmaking processes and (2) achieving the recovery of high-purity CO₂ postcombustion, thereby facilitating the carbon neutrality pathway with minimized separation energy consumption. However, components such as CO and N₂ in the gas lead to competitive adsorption, low catalytic selectivity, and complex reaction pathways, necessitating breakthroughs in catalytic mechanisms and process innovation.

This Account based on the research accumulation of the authors’ team in the field of CO₂ catalytic reduction and iron and steel metallurgy systematically reviews the key scientific issues and technological advancements in the catalytic conversion of LCC, using converter gas as a typical case. First, addressing the challenge of selective CO₂ adsorption, the competitive mechanisms of different adsorption models in complex gas environments were explored. Second, in terms of activation and reaction pathway regulation, the influence patterns of gases such as CO and N₂ on the CO₂ reduction reaction are analyzed. Furthermore, through in-depth analysis, new principles and processes for CO₂ adsorption in novel scenarios, catalyst matching, and directional design, material surface reconstruction under industrial environmental conditions is considered. Finally, we integrate the LCC reduction technology into the synergistic steel-chemical production technology route, focusing on elucidating the scientific design principles of meso-macro bridging in the engineering application process, providing a reference for the treatment of various industrial flue gases and tail gases.

The LCC catalytic reduction technology aids steel industry carbon emission reduction through “source conversion-end utilization”, but its industrialization requires collaborative innovation in theory and engineering. Future efforts should focus on the catalytic surface and interface mechanisms under complex gaseous conditions, develop highly efficient and stable catalysts, and design an integrated intelligent system of “catalysis-calorific value-chemical” to promote the near-zero carbon transformation in the steel industry. This technology not only supports carbon neutrality in the steel industry but also provides interdisciplinary solutions for CO₂ resource utilization in the chemical and energy sectors.