The impact of hydrogen on forced-draft gas burners: A numerical investigation of nitrogen oxide emissions

Numerical efficient CFD investigations of a full-scale, commercially available, forced-draft gas burners were carried out to map the nitrogen oxide emissions from pure natural gas to pure hydrogen operation. The validation data was provided by a series of tests, in which the thermal power of 358 kW was maintained by a boiler with an equal air excess ratio of 1.2. It was demonstrated that the Steady Diffusion Flamelet model is capable of reproducing nitrogen oxide emissions that correlate well with the experimental investigations of natural gas with a hydrogen content upwards of 70 vol%. In the examination of pure hydrogen combustion, the Flamelet Generated Manifold model exhibits optimal performance, deviating 1.3 % from the experimental data, when varying the Initial Scalar Dissipation parameter. • Numerical efficient NO x investigations for forced-draft gas burners. • Validation of complete operating points from pure NG to pure H 2 combustion. • Effect of H 2 enrichment in natural gas on temperatures and NO x formation. • Suitability of available flamelet models for pure NG to pure H 2 combustion.