Optimization model of mass and energy in the electric arc furnace using green direct reduced iron

The urgent need to decrease CO 2 emissions from the steel industry has focused attention on steel production in the electric arc furnace (EAF), which produces 20% of the CO 2 emissions of the blast furnace-basic oxygen furnace (BF-BOF) route. This result is possible using high-quality scrap, which is scarce and expensive. To compensate for the scrap deficit, direct reduced iron (DRI) has attracted renewed interest for producing high-quality steels. Although DRI offers several advantages over steel scrap, it also has major disadvantages, including higher energy consumption, higher gangue content, lower metallic yield, higher production costs, and higher CO 2 emissions. To critically assess the optimum use of DRI in the EAF, an optimization model with a cost minimization objective has been developed, linking energy consumption, CO 2 emissions, and production cost. The model is formulated using a general EAF mass and energy balance (MEB) framework, while the economic analysis is based on the Chinese market prices. This work is valuable considering that most previous work has focused on steel scrap. The results show that DRI's disadvantages can be controlled through careful analysis of its physical and chemical properties and metallurgical practice. The model identifies the key variables governing energy consumption when using DRI. The analysis of CO 2 emissions clearly indicates that scope 1 emissions from the EAF are almost irrelevant in comparison with the scope 3 emissions from upstream processes. This finding should play a major role in defining the future use of C-DRI and H-DRI in the EAF. A comprehensive comparison with previous literature results is also presented.