Challenges and Opportunities of Agricultural Biomass as a Replacement for PCI Coal in the Ironmaking Blast Furnace: A Review

Steel production is regarded as one of the primary greenhouse gas emission sources where fossil carbon-bearing fuels are used as chemical reducing agents and a source of energy. Due to the dual role of carbon (iron ore reduction and heating) in the blast furnace ironmaking process, biocarbon-based renewable energy sources may serve as a prospective low-emission alternative to fossil fuel carbon. In recent times, there has been a rapid rise in global concerns regarding climate change issues attributed to excessive CO 2 emission in the atmosphere. As a result, a significant emphasis has been imposed on the iron and steel industry to reduce their high CO 2 emission levels. Until now, woody biomass has mainly been considered for producing biocarbon for the blast furnace ironmaking process. Due to the presence of higher alkali and alkaline earth metal compounds, as well as phosphorus compounds, biocarbon from agricultural biomass has not been regarded as a potential replacement for metallurgical coal in the ironmaking process and therefore has not been deeply explored. In this review, various existing and promising routes for biomass conversion into biocarbon and their limitations are described. Finally, a hybrid hydrothermal carbonization and slow pyrolysis process is proposed to convert agricultural biomass into biocarbon, which has the potential to replace PCI coal in the blast furnace and other fossil fuels in iron and steelmaking processes. Graphical Abstract