LCA-based comparative assessment of ACI and SCR for gaseous elemental mercury emission control in coal-fired power plants

초록

Many researchers have developed selective catalytic reduction (SCR) and activated carbon injection (ACI) technologies to control gaseous mercury emissions from coal-fired power plants, which pose serious risks to human health and ecosystems. This study employs life cycle assessment (LCA) to compare the environmental impacts of SCR and ACI for gaseous elemental mercury (Hg0) removal. To eliminate annual mercury emissions equivalent to 78 kg-Hg0, SCR (0.027 kPt) exhibits a substantially lower environmental burden than ACI (0.483 kPt), which requires greater material and energy inputs. Sensitivity analysis identifies key parameters—catalyst replacement cycle (2–4 years), vanadium content (1%–2.5%), adsorbent efficiency (50%–100%), adsorbent performance (2.36–44.84 μg-Hg0/g-Biochar), and biomass sourcing (free supply, rice husk, and wheat straw)—all of which, except biomass sourcing, show an inverse correlation with total environmental impact. Notably, the long-term environmental burden of ACI exceeds that of untreated mercury emissions, primarily due to high diesel consumption for landfill maintenance. Overall, the results suggest that SCR represents a more sustainable option for mercury emission control in coal-fired power plants. © 2025 American Institute of Chemical Engineers.

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