CO assisted NH<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"><mml:msub><mml:mrow/><mml:mn>3</mml:mn></mml:msub></mml:math> oxidation

Alzueta, María U.; Salas, Iris; Hashemi, Hamid; Glarborg, Peter

doi:10.1016/j.combustflame.2022.112438

Cited by 13 publications

(9 citation statements)

References 61 publications

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“…The main products measured in significant amounts during the conversion of NH 3 /CH 4 mixtures are NO, N 2 O, N 2 , H 2 , CO, and CO 2 . N 2 and N 2 O are the most abundant nitrogen species since NO is consumed by reaction with NH 3 . NO 2 is below 10 ppm in all studied experimental conditions, which is consistent with the results of the previous studies for pure ammonia oxidation …”

Section: Resultssupporting

confidence: 92%

“…The experimental results of the present work are simulated using a gas-phase chemical kinetic mechanism based on earlier work on nitrogen chemistry by Glarborg et al, drawing on more recent work on amine chemistry by Stagni et al, updated adding an acetonitrile reaction subset by Alzueta et al as well as a reaction subset of methylamine by Glarborg et al, updated by Marrodán et al, and including modifications and/or recommendations of the recent studies of Burke, Klippenstein et al, Marshall et al, Alzueta et al, , and Glarborg et al − Reactions recently revised such as NH 2 + HO 2 by Klippenstein et al and NH 2 + NO 2 by Glarborg, as well as steps involved in amine pyrolysis , and H 2 NO reactions proposed by Stagni et al were included as well. Other steps involved in amine chemistry are updated from the work of Cobos and Gao. , …”

Section: Kinetic Modelingmentioning

confidence: 99%

“…It is important to mention as well that some studies at atmospheric pressure focused on determining the effects of NO concentration on ammonia chemistry during NH 3 /CH 4 mixtures oxidation. ,,, Also, the effects of CO/CO 2 are also studied on NH 3 oxidation in a flow reactor with the aim of addressing possible oxy-fuel combustion strategies. ,,− …”

Section: Introductionmentioning

confidence: 99%

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Experimental and Modeling High-Pressure Study of Ammonia–Methane Oxidation in a Flow Reactor

García-Ruiz,

Salas,

Casanova

et al. 2024

Energy Fuels

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The present work deals with an experimental and modeling analysis of the oxidation of ammonia−methane mixtures at high pressure (up to 40 bar) in the 550−1250 K temperature range using a quartz tubular reactor and argon as a diluent. The impact of temperature, pressure, oxygen stoichiometry, and CH 4 / NH 3 ratio has been analyzed on the concentrations of NH 3 , NO 2 , N 2 O, NO, N 2 , HCN, CH 4 , CO, and CO 2 obtained as main products of the ammonia−methane mixture oxidation. The main results obtained indicate that increasing either the pressure, CH 4 /NH 3 ratio, or stoichiometry results in a shift of NH 3 and CH 4 conversion to lower temperatures. The effect of pressure is particularly significant in the low range of pressures studied. The main products of ammonia oxidation are N 2 , NO, and N 2 O while NO 2 concentrations are below the detection limit for all of the conditions considered. The N 2 O formation is favored by increasing the CH 4 / NH 3 ratio and stoichiometry. The experimental results are simulated and interpreted in terms of an updated detailed chemical kinetic mechanism, which, in general, is able to describe well the conversion of both NH 3 and CH 4 under almost all of the studied conditions. Nevertheless, some discrepancies are found between the experimental results and model calculations.

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Section: Resultssupporting

confidence: 92%

Section: Kinetic Modelingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental and Modeling High-Pressure Study of Ammonia–Methane Oxidation in a Flow Reactor

García-Ruiz,

Salas,

Casanova

et al. 2024

Energy Fuels

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“…However, the failure of the model to capture the observed results persists. Recently, Alzueta et al 49 reported similar discrepancies for oxidation of CO/NH 3 mixtures in a quartz reactor at low O 2 . More work is desirable to resolve this issue.…”

Section: The Journal Of Physical Chemistrymentioning

confidence: 75%

Probing High-Temperature Amine Chemistry: Is the Reaction NH₃ + NH₂ ⇄ N₂H₃ + H₂ Important?

Marshall

Glarborg

2023

J. Phys. Chem. A

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The reaction NH 3 + NH 2 ⇄ N 2 H 3 + H 2 (R1) has been identified as a key step to explain experimental results for pyrolysis and oxidation of ammonia. However, no direct experimental or theoretical evidence for the reaction has been reported. In the present work, the reaction was studied by ab initio theory and by reinterpretation of experimental data. We could not locate a transition state for R1 occurring as a direct process, but alternative mechanisms yielded an upper bound to k 1 of 1.5 × 10 13 exp(−58.9 kcal mol −1 /RT) cm 3 mol −1 s −1 over 1000−2500 K, several orders of magnitude lower than values applied in modeling. Consistent with the theoretical work, re-evaluation of NH 3 pyrolysis data supported a very low value of k 1 . However, this finding opens up a novel unresolved issue. Current kinetic models cannot capture the NH 3 oxidation behavior in a number of laminar flow reactor and jet-stirred reactor experiments without adopting an improbably high value for k 1 . Important oxidation steps might be underestimated or missing from mechanisms.

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“…The chemical kinetic model, including rate coefficients and thermodynamic data, is adapted from the recent study of NH 3 oxidation by Jian et al The core of the mechanism is drawn from the review of nitrogen chemistry by Glarborg et al, but with modifications based on more recent work. , The H 2 –O 2 subset , was updated according to the work of Klippenstein and co-workers on chemically termolecular reactions H + O 2 + R and on HO 2 + HO 2 . The amine subset was revised based on work on NH 2 + H (+M), , NH 3 + HO 2 , NH 2 + O, NH 2 + HO 2 , , as well as steps in the diazene, H 2 NO, and HNO , subsets.…”

Section: Detailed Chemical Kinetic Modelmentioning

confidence: 99%

Flow Reactor Oxidation of Ammonia–Hydrogen Fuel Mixtures

Alzueta,

Mercader,

Cuoci

et al. 2024

Energy Fuels

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Hydrogen-assisted oxidation of ammonia under flow reactor conditions was investigated through experiments and chemical kinetic modeling. Novel experiments, conducted in a tubular laminar flow reactor as a function of the NH 3 /H 2 ratio, stoichiometry, and temperature (725−1475 K), were analyzed along with literature results from tubular and jet-stirred flow reactors. Ignition and oxidation of NH 3 is strongly promoted by the presence of H 2 under all conditions investigated. In general, the behavior is captured well by the kinetic model. With an increasing fraction of H 2 in the fuel mixture, the generation of chain carriers gradually shifts from being controlled by the amine reaction subset to being dominated by the oxidation chemistry of H 2 , which is known more accurately. However, under reducing conditions, the H 2 consumption rate is strongly underpredicted. This shortcoming suggests that the thermochemistry of amine radicals and/or the formation of higher amines need further assessment. The present analysis shows that for lean oxidation of NH 3 /H 2 mixtures in tubular flow reactors, data obtained at higher temperatures, particularly for NO formation, may be strongly affected by the reaction during preheating or by mixing (dependent on reactor design) in the inlet section prior to the isothermal zone. Modeling predictions for the high pressure, medium-temperature ignition conditions in a large diesel engine indicate that NH 3 /H 2 fuel mixtures may still require a cofuel to secure stable ignition.

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CO assisted NH3 oxidation

Cited by 13 publications

References 61 publications

Experimental and Modeling High-Pressure Study of Ammonia–Methane Oxidation in a Flow Reactor

Experimental and Modeling High-Pressure Study of Ammonia–Methane Oxidation in a Flow Reactor

Probing High-Temperature Amine Chemistry: Is the Reaction NH₃ + NH₂ ⇄ N₂H₃ + H₂ Important?

Flow Reactor Oxidation of Ammonia–Hydrogen Fuel Mixtures

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CO assisted NH3 oxidation

Cited by 13 publications

References 61 publications

Experimental and Modeling High-Pressure Study of Ammonia–Methane Oxidation in a Flow Reactor

Experimental and Modeling High-Pressure Study of Ammonia–Methane Oxidation in a Flow Reactor

Probing High-Temperature Amine Chemistry: Is the Reaction NH3 + NH2 ⇄ N2H3 + H2 Important?

Flow Reactor Oxidation of Ammonia–Hydrogen Fuel Mixtures

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Probing High-Temperature Amine Chemistry: Is the Reaction NH₃ + NH₂ ⇄ N₂H₃ + H₂ Important?