A case study on biomass steelmaking in electric arc furnaces: Mass,energy and emission analysis

Abstract

Biomass resources are regarded as a promising renewable energy alternative to fossil fuels in electric arc furnace (EAF) steelmaking. This research evaluates the feasibility of replacing natural gas (NG) with biomethane and coke fines with biochar in full-scrap EAF steel production through mass-energy, economic and emissions analyses. Results show that fully substituting NG with biomethane at 4.51 Nm³/t (136.6 MJ/t) increases production costs by about 0.4 to 1.6 USD/t. Replacing coke fines with biochar requires 25.6 kg/t of wood biochar (WB), 39.4 kg/t of rice husk biochar (RHB) and 60.0 kg/t of corn stover biochar (CSB). Power consumption changes include a decrease of 4.2 kWh/t for WB, and increases of 41.5 kWh/t for RHB and 63 kWh/t for CSB, relative to a baseline of 359.3 kWh/t crude steel (CS). These replacements increase production costs by approximately $7 to $23 USD/t. Regarding CO₂ emissions, biomethane substitution reduces emissions by 8.9 kg CO₂ eq/t CS (2.2%), while complete substitution with WB achieves the highest reduction of 83.8 kg CO₂ eq/t CS (20.9%). In contrast, RHB and CSB increase emissions by 3.6 and 42.7 kg CO₂ eq/t CS, respectively. Combining biomethane with WB can cut CO₂ emissions by 92.7 kg per ton of CS during EAF steelmaking. Overall, these findings indicate that biomass options could significantly enhance the environmental sustainability of EAF steelmaking.