A Numerical Study of Options for Improving Carburization in a Hydrogen-Intensive Direct Reduction Shaft Furnace

This study delves into the challenges and solutions for improving carburization in hydrogen-intensive direct reduction (DR) shaft furnaces, a critical step towards achieving low-carbon steel production. The research investigates the effects of varying hydrogen content in the reducing gas on the thermochemical state and furnace performance, highlighting the endothermic nature of hydrogen reduction and its impact on carburization. The study proposes several strategies to enhance carburization, including increasing the feed rate of reducing gas, using pure methane as carburization gas, extending the carburization zone, and preheating the carburization gas. The findings demonstrate that preheating the carburization gas significantly improves the carbon content of the direct reduced iron (DRI), suggesting that hot DRI production is a promising option for hydrogen-intensive shaft furnaces. The study also emphasizes the importance of optimizing the pressure at the carburization gas outlet to achieve maximum DRI metallization. Overall, the research provides valuable insights into the technical guidelines for transitioning from fossil-based to hydrogen-intensive direct reduction in shaft furnaces, contributing to the development of sustainable steelmaking technologies.