Impact of hydrogen metallurgy on the current iron and steel industry: A comprehensive material-exergy-emission flow analysis

The development of hydrogen metallurgy holds enormous significance in facilitating the low-carbon and environmentally sustainable transition of iron and steel industries. However, there is a lack of research on the impact of implementing hydrogen metallurgy on the downstream process and even the whole process. To fill this research gap, a model that considers specific internal reactions of steelmaking process was developed utilizing the bottom-up approach. Subsequently, by integrating the hydrogen metallurgy process with the traditional long process and short process, the energy intensity, exergy intensity and carbon emission intensity were quantitatively analyzed from multiple viewpoints. The results of the basic oxygen furnace (BOF) and electric arc furnace (EAF) exhibit a degree of similarity, with an increase in directly reduced iron (DRI) addition, resulting in an insufficient heat and an increase in process energy consumption, exergy loss, and carbon emissions. But there are also some subtle differences, such as oxygen consumption. Following the integration of hydrogen metallurgy, the energy intensity and exergy intensity of the BF-BOF process increase 11.984 kgce/t-CS and 3.083 x 102 MJ/t-CS, respectively. However, the carbon emission intensity decreased by 46.514 kg/t-CS. The integrated Chinese-style short process has the lowest carbon emission intensity of 879.664 kg/t-CS at 40% DRI and 60% scrap. Nevertheless, the energy intensity and exergy intensity have increased by 27.383 kgce/t-CS and 42.012 x 102 MJ/t-CS respectively compared to their initial values. It is noteworthy that the process of hydrogen production plays a significant role in mitigating the exergy intensity and carbon emission intensity.