Journal Article

Fundamentals of Green Steel Production: On the Role of Gas Pressure During Hydrogen Reduction of Iron Ores

Springer, H., Raabe, D., Ma, Y., Souza Filho, I. R.

2023

Overview

Out of the multitude of researched processing routes for sustainable ironmaking, hydrogen-based direct reduction and hydrogen plasma smelting reduction (HyPSR) are currently the most promising candidates for a successful industrial application. Both processes operate under gaseous atmospheres, which turn the partial and absolute pressure of hydrogen into a relevant process parameter. Here, we present first insights into the influence of total pressure and concentration of hydrogen on the reduction of hematite, focusing on the more pressure-sensitive route (HyPSR). The effect of pressure on the dissociation of H 2 molecules into metastable H atoms or H + ions,- and the overall hydrogen utilization is discussed using a thermodynamic approach. Validation experiments were conducted to testify the practical feasibility of adjusting these parameters. A decrease in the total pressure of the system from 900 mbar to 450 mbar resulted in an improved hydrogen utilization, thus suggesting that a larger population of H atoms can exist in the plasma arcs ignited under 450 mbar. An increase in the hydrogen concentration to 20 vol.% lead to undesired evaporation, likely because of a parallel increase in plasma temperature. Possibilities and challenges for exploiting these pressure-related phenomena for the industrial production of green steel are outlined and discussed.

• Publisher: Springer US,Springer Nature B.V
• Subject: Alternative energy / Applications of Steels for a Sustainable Future / Atmospheric pressure / Chemical reactions / Chemistry/Food Science / Design / Design, Production, and Applications of Steels for a Sustainable Future / Direct reduced iron / Earth Sciences / Efficiency / Engineering / Environment / Fluidized bed reactors / Gas pressure / Gases / Hematite / Hydrogen / Hydrogen plasma / Hydrogen reduction / Industrial applications / Influence / Iron compounds / Iron ores / Ironmaking / Metallurgy / Natural gas / Physics / Plasma / Plasma jets / Plasma temperature / Pressure effects / Process parameters / Production / Smelting reduction / Steel making / Steel production