Numerical investigation of the potential of using hydrogen as an alternative fuel in an industrial burner

This study investigates hydrogen and hydrogen-methane mixtures as alternative fuels for industrial burners, focusing on combustion dynamics, flame stability, and emissions. CFD simulations in ANSYS Fluent utilized the RANS framework with the k-ε turbulence model and the mixture fraction/PDF approach. Supporting Python scripts and Cantera-based kinetic modeling employing the GRI-Mech 3.0 mechanism and Zeldovich pathways analyzed equivalence ratios (Φ), adiabatic flame temperatures (T_ad ), and NO_x formation mechanisms. Results revealed non-linear temperature trends, with a 50% hydrogen blend yielding the lowest peak temperature (1880 K) and a 75% hydrogen blend achieving optimal performance, balancing peak temperatures (∼1900 K), reduced NO_x emissions (5.39 × 10^-6), and near-zero CO₂ emissions (0.137), though flame stability was impacted by rich mixtures. Pure hydrogen combustion produced the highest peak temperature (2080 K) and NO_x emissions (3.82 × 10-5), highlighting the need for NO_x mitigation strategies. Mass flow rate (MFR) adjustments and excess air variation significantly influenced emissions, with a 25% MFR increase reducing NOx to 2.8 × 10^-5, while higher excess air (e.g.,30%) raised NO_x under lean conditions. Statistical analysis identified Φ, hydrogen content (H₂%), and flame stability as key factors, with 50%–75% hydrogen blends minimizing emissions and optimizing performance, emphasizing hydrogen’s potential with controlled MFR and air adjustments.

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Published in: Fuel
License: http://creativecommons.org/licenses/by/4.0/
See article on publisher's website: https://dx.doi.org/10.1016/j.fuel.2024.134194