Detailed Reaction Mechanism for the Combustion of Hydrogen and Syngas
Description
A detailed reaction mechanism for the oxidation of hydrogen and syngas in freely propagating and burner-stabilized premixed flames as well as shock-tube, jet-stirred reactor, and plug-flow reactor experiments is developed. The H2/CO kinetic model is validated against experimental data from literature which include 87 sets of laminar flame speed, 39 sets of ignition delay times from shock tubes, 16 sets species concentrations in JSRs, 27 sets of species concentrations in PFRs, 8 sets of species concentrations in BSF and 4 sets of species concentrations in shock tube experiments. The rate parameters adopted to develop the detailed chemical kinetic mechanism of H2 and CO is mostly based on the recommendations of Baulch et al. 2005 (Journal of Physical and Chemical Reference Data 34, 757 (2005). https://doi.org/10.1063/1.1748524). This mechanism was developed in parallel to the ammonia mechanism (Detailed Kinetic Mechanism for the Oxidation of Ammonia Including the Formation and Reduction of Nitrogen Oxides. Energ Fuels 2018;32:10202−10217. doi:10.1021/acs.energyfuels.8b01056).
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Steps to reproduce
The rate parameters adopted to develop the detailed chemical kinetic mechanism of H2 and CO is mostly based on the recommendations of Baulch et al. 2005 (Journal of Physical and Chemical Reference Data 34, 757 (2005). https://doi.org/10.1063/1.1748524). The software package used in this work is LOGEsoft v1.08 Numerical model used for simulation 1. Laminar premixed Flame The laminar flame speed and species prediction in burner stabilized premixed flame are performed by using the mixture average transport model. The mixture average transport model assumes the same diffusion coefficients for all the species in the flame. For calculating laminar flame speed freely propagating flame setup is used and for speciation and temperature profile in burner stabilized flame burner stabilized flame setup is used in LOGEsoft which solves the conservation of momentum equation, conservation of species equation and the conservation of energy equation. More details can be found on LOGEsoft manual. 2. Shock Tube (ST) Shock tubes are modelled as constant volume reactor model with the reflected shock pressure and temperature used as the initial conditions. The ignition delay time is predicted determined as per the definition used in the experiment. 3. Jet Stirred Reactor (JSR) The species profile data from JSR are compared with the predicted species profile from the Perfectly Stirred Reactor (PSR) model setup. The PSR model assumes the constant pressure vessel with inlet and outlet ducts. In the simulation we employed the steady state, constant temperature condition for all the simulation performed. 4. Flow Reactor The species profile from the variable pressure flow reactor are compared with the predicted species profile assuming a constant pressure reactor model. The initial conditions are taken from the experiment. However, the model assumes perfect and instantaneous mixing of the reactants, which may not be the case during the experiments. As suggested by other authors, the time at which reaction starts in the experiments is not well defined, and it is reasonable to shift the predicted species profiles relative to the measured profiles to account for non-idealities in reaction initiation by various causes. This profile is shifted in time so that the predicted point corresponding to 50% of the fuel disappearance matches that reported experimentally.