Optimization of Ammonia Mixing in Selective Catalytic Reduction (SCR) Systems: A Computational Fluid Dynamics (CFD) Study on Swirl Angle and Mass Flow Rate Effects

Gutti Lokesh Kalyan; Rajendra Singh Rajput; Sunkara Srinivasa Rao; Mukesh Kumar Pandey

doi:10.54392/irjmt25319

Authors

Gutti Lokesh Kalyan Department of Mechanical Engineering, ITM University, Gwalior, 474001, Madhya Pradesh, India Author https://orcid.org/0009-0004-1265-8712
Rajendra Singh Rajput Department of Mechanical Engineering, ITM University, Gwalior, 474001, Madhya Pradesh, India Author https://orcid.org/0000-0002-9976-6449
Sunkara Srinivasa Rao Department of Electronics and Communication Engineering, Koneru Lakshmaiah Education Foundation, Bowrampet, Hyderabad, 500043, Telangana, India Author https://orcid.org/0000-0002-1308-7067
Mukesh Kumar Pandey Department of Civil Engineering, ITM University, Gwalior, 474001, Madhya Pradesh, India Author

DOI:

https://doi.org/10.54392/irjmt25319

Keywords:

Selective Catalytic Reduction (SCR), Swirl Angle θ, Gas Turbine (GT) diffuser, Ammonia (NH₃) mixing

Abstract

The research deals with design a Heat Recovery Steam Generator (HRSG) model through Computational Fluid Dynamics (CFD) to evaluate Selective Catalytic Reduction (SCR) deNOₓ procedures that help maintain sustainable environmental emissions. We study six swirl angles ranging from θ = 10° to θ = 60° at the GT diffuser exit to determine how they affect ammonia (NH₃) mixing before the SCR catalyst bed. The evaluation process occurred under mass flow conditions of 350 kg/s and 700 kg/s. Ammonia mixing uniformity must comply with Industrial standards by keeping the RMS value of mole fraction distribution less than 5% according to manufacturer specifications. The results indicate that a swirl angle of 30° produces the best NH₃ mixing performance with RMS 4.27% and theta = 40° provides the best temperature distribution ranging within ±7.41°C. The research delivers vital information regarding SCR system optimization when operational parameters change.

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