Optimizing MAF-ENF-CO2 coordination in steel mills: system modeling and emission reduction scenarios

This study develops an innovative three-dimensional "Material Flows–Energy Flows–CO₂" (MAFs–ENFs–CO₂) model that integrates MAFs, ENFs, and carbon emissions across blast furnace–basic oxygen furnace systems. This framework systematically quantifies the interactions and propagation effects between production variables and emission drivers across macro-policy, meso-technological, and micro-operational levels. Through scenario analysis, five key decarbonization pathways are identified: increasing the scrap steel ratio to 30% (reducing emissions by 1.9967 million tons, MTs), lowering the steel slag generation ratio by 10%, optimizing the pellet ratio to 13%, enhancing waste heat recovery, and substituting coal with natural gas. Clean energy substitution and scrap ratio improvement dominate mitigation potential, contributing 81.5% of total reductions (6.6571 MTs). The model elucidates the quantitative relationships between material adjustments, process optimizations, and energy transitions, providing a robust accounting framework that effectively connects operational parameters to policy-driven decarbonization targets. This integrated approach offers actionable pathways for source reduction, process efficiency, and end-treatment integration in steel production, supporting China’s carbon peak and neutrality goals and providing a scalable roadmap for energy-intensive industries globally.