Author(s)

ZePeng Li¹, Yasser M. A. Mohamed^2*, YingHui Han^1*

Affiliation(s)

¹ College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 101408, China.

² Photochemistry Department, National Research Centre, Dokki, Giza, P. O. 12622, Egypt.

Corresponding Author

Yasser M. A. Mohamed, YingHui Han

ABSTRACT

Selective catalytic reduction (SCR) plays a critical role in achieving ultra-low emissions from coal-fired power plants by enabling highly efficient removal of nitrogen oxides (NOx). However, the denitrification process may concurrently generate nitrous oxide (N₂O), a potent greenhouse gas often overlooked in emission control strategies. Crucially, conventional continuous emission monitoring systems (CEMS) focus solely on NOx reduction efficiency without tracking byproduct formation, creating a potential blind spot for N₂O emissions when reduction reactions are incomplete. To address this gap, this study conducted multi-point on-site sampling monitoring within SCR system of ultra-low emission units at a 693 MW coal-fired power plant and a separate 2× 300 MW plant. A pivotal question was investigated: Are N₂O emissions inevitably elevated by SCR operation? Our findings reveal significant spatial heterogeneity in N₂O distribution: while concentrations increased at certain locations (e.g., upstream catalyst layers), they unexpectedly decreased at others (e.g., optimized mid-reactor zones), demonstrating position-dependent synergistic reduction of NOx and N₂O under specific operational conditions. This work highlights the necessity of multi-dimensional emission assessment beyond standard CEMS protocols and provides actionable insights for co-controlling air pollutants and greenhouse gases in industrial air pollution control systems.

KEYWORDS

Nitrous oxide; Nitrogen oxide; Selective catalytic reduction; Ultra-low emission; Coal-fired power plant

CITE THIS PAPER

ZePeng Li, Yasser M. A. Mohamed, YingHui Han. Revealing heterogeneity of N₂O concentration in selective catalytic reduction denitrification: a multi-point sampling study in coal-fired power plant. Frontiers in Environmental Research. 2025, 3(2): 63-66. DOI: https://doi.org/10.61784/fer3031.

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