Influence of emissions normalisation methods on H2–CH4 fuel comparisons in generic and NOx-Abated gas turbine combustion

Parametric experiments were performed using CH 4 –H 2 blends to fuel a model gas turbine combustor at elevated inlet conditions, unabated and whilst employing exhaust gas recirculation (EGR) as a NO x -abatement technique. The purpose was to quantify the performance of conventional dry, 15% O 2 NO x correction (ISO) against mass by heat input (MBHI) normalisation to experimentally verify simulated work from the literature, while expanding on this work to cover NO x -abated combustion. NO x was found to be consistently inflated in H 2 combustion when compared to CH 4 by the ISO method, whereas the MBHI method was found to closely approximate the mass by work output baseline emissions. Multipliers proposed to correct this inflation were shown to be impractical. A fundamental problem in assessing the effectiveness of EGR using the ISO method was identified as it does not account for the additional volumetric dilution introduced, whereas the MBHI normalisation method avoids this issue. • ISO-11042 NO x emissions exaggeration in H 2 flames demonstrated practically. • Degree of exaggeration aligns well with simulated results from the literature. • Fundamental problem with ISO-11042 method identified when assessing EGR results. • “Mass by heat input” normalisation method from literature is more representative.