Gas utilization optimization and exergy analysis of hydrogen metallurgical shaft furnace

For the objective of carbon neutrality stated by the global climate conference, the iron and steel industry, a major carbon emitter, must transition to green and low-carbon development as quickly as feasible. Hydrogen metallurgy direct reduction technology has attracted much attention because of its low emission. However, the current study on hydrogen metallurgy shaft furnace lacks a comprehensive in-depth analysis of gas consumption, gas utilization, and exergy intensity. To tackle these problems, a material and energy optimization model including intermolecular chemical reaction is established. The original process is optimized by this model, the gas utilization is enhanced by 26.7%, gas consumption is decreased by 906.34 m3/t-DRI, and exergy intensity is reduced by 8.8 GJ/t-DRI. Furthermore, the impacts of gas composition, gas temperature, and ore temperature on gas consumption, gas utilization, exergy structure, and exergy intensity, as well as their interactions, are investigated thoroughly. The analysis highlighted that properly reducing hydrogen content and increasing gas and ore temperature can improve gas utilization and reduce gas consumption. Simultaneously, lowering gas consumption can effectively lower exergy intensity. And furnace top gas exergy is closely related to gas utilization. On the whole, it is advantageous to promote the development of hydrogen metallurgy by conducting in-depth and systematic analyses.