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.