Role of Torrefaction and Briquetting in Improving Biomass Suitability for Iron Ore Sintering

It has been established through the present study that biomass is very promising as an alternative fuel that is eco-friendly and renewable for iron ore sintering. Nonetheless, various unfavorable attributes, such as excessive moisture, low density, high volatiles, low grindability, and unpredictable burning, prevent the utilization of the biomass feedstock as-is in its natural state. In industrial sintering operations, these limitations reduce thermal efficiency and pose operational difficulties. Torrefaction emerged as an effective method of upgrading biomass, which enhanced numerous physical, chemical, and thermal properties of the biomass fuel. The process elevated carbon content, energy value, hydrophobicity, and burning efficiency while reducing moisture and volatiles. Torrefied biomass is more suitable for combustion along with conventional fuels due to better grindability and coal-like nature of biomass in iron ore sintering plants.Moreover, the study revealed that briquetting improved the suitability of biomass due to higher bulk density, mechanical strength, storage ability, and transportation properties. As compared with loose raw biomass, biomass briquettes have proved more stable and effective in terms of combustion efficiency, low dust formation, and improved handling properties. Stable combustion leads to better heat generation in the sintering bed, resulting in stable sinter formation.From experimental results, it was found that utilization of torrefied biomass as a partial substitute for coke breeze reduces GHG emissions, fossil fuel consumption, and no significant decrease was observed in the production of sinter. Due to their low sulfur and nitrogen content, biomass-based fuels emitted lower levels of sulfur oxide and nitrogen oxide, thus promoting environmentally friendly steel production techniques.Despite the advantages associated with torrefaction and briquetting, there are several constraints such as preprocessing cost, energy input, biomass availability, and process optimization that hinder their full industrial implementation. For industrial-level processes, there is a need for further research on optimal conditions for torrefaction, biomass replacement rates, reactor design, and cost-effectiveness.Having analyzed all aspects, torrefied and briquetted biomass can be considered an appropriate fuel source for iron ore sintering and has a great potential to reduce carbon footprint, improve waste management, and foster sustainable development in the iron and steel industry.

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