| SESSION: CarbonThuPM1-R7 |
8th Intl. Symp. on Sustainable Carbon and Biocoke and their Industrial Application |
| Thu. 20 Nov. 2025 / Room: Lotus | |
| Session Chairs: Paulo Assis; Philip Aster; Student Monitors: TBA | |
The iron and steel sector is a key driver of global economic development and is one of the largest consumers of industrial energy, largely dependent on fossil fuels. Within this sector, sinter making is a vital step in the ironmaking process, accounting for approximately 10% of total energy use—of which about 78% is derived from coke breeze. This heavy reliance contributes substantially to greenhouse gas emissions, as well as SOx and NOx pollutants. Replacing fossil fuels with biomass, a renewable and cleaner energy source, presents a promising path toward carbon-neutral sintering. This study explores the potential of biochar, obtained through the pyrolysis of biomass, as a viable and sustainable fuel alternative in the sintering process. The present study investigates the feasibility of replacing solid fuel upto 100 % within the sintering process with biochar through lab scale sinter pot trials. Biochar's high carbon content, improved energy density, and low volatile matter make it a promising candidate for enhancing thermal efficiency and reducing greenhouse gas emissions. Charcoal with a size fraction of -3.15 mm was used for the current trials. In comparison to the conventional mix, sinter blends incorporating charcoal demanded higher moisture content to attain effective granulation, primarily due to charcoal's higher porosity and moisture absorption capacity. The use of charcoal as a partial fuel substitute in the sintering process led to a noticeable reduction in the green mix bulk density due to its inherently lower material density. This change also contributed to a decline in the balling index, indicating weaker pellet formation. Additionally, increased charcoal content disrupted the consistency of the heat and flame fronts, resulting in reduced thermal efficiency and a subsequent decrease in sinter yield. However, the higher combustibility and volatile matter of charcoal enabled faster temperature build-up, which shortened the overall sintering time. Despite these changes, sinter productivity remained within an acceptable operational range. The presence of charcoal affected the exhaust gas composition, with a reduction in overall SO2 and NOx emissions. With increasing biochar substitution, NOx emissions were reduced from approximately 100 ppm to 34 ppm, while SO₂ emissions decreased from around 5.3 ppm to 3.3 ppm.