Computational Study of NO x Formation at Conditions Relevant to Gas Turbine Operation, Part 2: NO x in High Hydrogen Content Fuel Combustion at Elevated Pressure

Part 1 (10.1021/acs.energyfuels.6b00420) of this two part series presented a computational study of NO x formation during methane and ethylene combustion, representative of small fuel fragments present in natural gas and chemical processing. The influence of fuel chemistry, reaction temperature history, and inert dilution was examined using popular models present in the literature. The present work extends the study to hydrogen-rich conditions to remove the fuel variability dependency of NO x and identify possible inconsistencies in predicting NO x during high hydrogen content fuel combustion. A comprehensive chemical kinetic model is proposed consisting of CO/H2/NO x oxidation with the full implementation of thermal, N2O, and NNH paths of NO x evolution. Predictions from the model are compared against multiple experimental data sets over a wide range of venues and operating conditions. The experimental venues include shock tube, plug flow reactor, and stirred reactor experiments that cover pressures from 1 to 100 bar and equivalence ratios from 0.5 to 1.5. In general, the overall model predictions are in good agreement with global combustion targets, such as ignition delay time, as well as with more detailed measurements from flow reactors and stirred reactors. Simulations are conducted for a wide range of reacting mixtures (H2/O2/N2, CO/H2/O2, and CO/H2O/O2/N2) with initial NO and NO2 perturbations to consider exhaust gas recirculation (EGR) conditions.