(315d) A Comprehensive NOx Kinetic Model for Predicting Emissions during High Hydrogen Content Fuel Combustion at Elevated Pressure

High hydrogen content (HHC) fuel and synthesis gas combustion in gas turbine and other applications is an important aspect of many energy conversion scenarios for generating power and producing alternative transportation liquid fuels. Developing/testing predictive models for NO_x formation continues to be important to evaluation/design of high efficiency, low emission technologies for HHC fuel and syngas combustion applications.  The present study investigates comprehensive detailed chemical kinetic models for describing the oxidation of CO/H₂/NO_x mixtures and limited amounts of small hydrocarbon species with the full implementation of NO_x evolution pathways, including thermal, prompt, N₂O and NNH paths. Model predicted behaviors are compared against multiple experimental datasets over a wide range of venues and operating conditions.  The experimental venues include shock tube, laminar-premixed flame, plug flow reactor, and perfectly stirred reactor experiments that cover pressures from 1 to 100 bar and equivalence ratios from 0.5 to 1.5. The Burke C₀ [Intl. J. of Chemical Kinetics 44, (2012), 444 – 474) and Aramco C₁-C₄ [Intl. J. of Chemical Kinetics 45, (2013), 638 – 675] models are integrated to describe the fuel kinetics. The NO_x kinetic components are developed based on a critical review of NO_x production, and NO-NO₂ interconversion sub- models presently available in the literature.  The NO_x sub-model includes N_xH_y reaction paths as well as updated rate expressions and species, such as HNO₂ and HONO₂ and the related paths are found to contribute to NO_x production significantly. In general, the overall model predictions are in good agreement with global combustion targets (shock tube ignition delay and premixed laminar burning velocity) as well as with more detailed target data including plug flow reactor reactivity, speciation, and perfectly stirred reactor measurements reported in the literature. Besides the data available in the literature, experiments are also conducted with a McKenna burner for generating additional model validation targets. The model was found to predict reasonably well these new experimental data. In addition, 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.