A Numerical Study on the Production Status Changes of Hydrogen-Based Shaft Furnace during H2 Replacement of Coke Oven Gas

Abstract

To address the increasingly stringent climate policies, steel production is inevitably moving toward a fossil-free future, and the hydrogen-based shaft furnace process is no exception. Natural gas and coke oven gas (COG), which currently serve as the primary gas sources, will inevitably be replaced by green H₂ in the future. This study investigates the operational changes of a hydrogen-based shaft furnace during the transition from COG to green hydrogen as the reducing gas. A numerical simulation model is used to analyze the effects of varying COG/H₂ ratios and top gas pressures on production status. The results demonstrate that as the ratio of H₂ increases, the endothermic reactions diminish. This reduces the temperature at the upper part of the reducing zone while increasing the temperature in the remaining areas. It also promotes an increase in the metallization degree but significantly reduces the carbon content. These changes have important implications for energy consumption and power on time in the Electric Arc Furnace (EAF) process. Additionally, increasing the top gas pressure not only enhances the metallization degree and carbon content but also reduces the diameter of fine powder entrained by the gas flow, thereby improving the yield.