Life Cycle Assessment of Different Hydrogen-Rich Reducing Gases Injected into a Blast Furnace
摘要
As fuel costs rise and energy scarcity intensifies, efficient utilization of by-product gases from the steel industry has become a key technological path for energy conservation and carbon reduction in blast furnaces. This study proposes injecting various by-product gases from steel production into blast furnaces. By increasing oxygen-enrichment and coal-injection rates, this approach aims to reduce coke consumption, lower the coke ratio, and boost output. However, the environmental impact and specific effects on CO2 emissions of injecting reducing gases into blast furnaces without prior decarbonization require systematic investigation. To address this, this study develops a life cycle assessment (LCA) model for blast furnace hot metal production. It analyzes the environmental impacts and carbon footprint characteristics of hot metal production under different by-product gas conditions. The results indicate that spraying untreated reducing gases can lead to different trends in the characterization results of different impact categories. Among them, the potential for global warming and energy intensity is most significantly affected. Among the four scenarios examined, the coke oven gas (COG) injection scenario has the least environmental impact. Specific CO2 emission totals for the four scenarios are 1697.9 kg/ton, 1721.2 kg/ton, 1747.7 kg/ton, and 1678.6 kg/ton. In the COG injection scenario, direct emissions from the blast furnace process decrease to 562.8 kg/ton, 610.5 kg/ton, and 571.4 kg/ton, reductions of 17.87%, 10.92%, and 16.63%, respectively. Indirect emissions from the oxygen-enrichment process increase to 243.1 kg/ton, 229.9 kg/ton, and 243.1 kg/ton. Additionally, CO2 emissions from coking and oxygen-enriched blasting decrease, while those from sintering remain relatively stable.