Ammonia oxidation at high pressure and intermediate temperatures

Song, Yu; Hashemi, Hamid; Christensen, Jakob Munkholt; Zou, Chun; Marshall, Paul; Glarborg, Peter

doi:10.1016/j.fuel.2016.04.100

Cited by 232 publications

(133 citation statements)

References 66 publications

(75 reference statements)

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“…The Cantera software 30 with Python interface was used in the computations. Computations employing other mechanisms in the literature revealed less discrepancy between the new predictions and experiments than had been found for some others, [32][33][34][35] which were overreactive by amounts up to a factor of 5 under these conditions. Premixed systems are characterized by the equivalence ratio, , defined on the basis of complete combustion of the reactants to carbon dioxide (CO 2 ), water (H 2 O), and nitrogen (N 2 ).…”

Section: Comparisons With Experimentsmentioning

confidence: 47%

“…As shown in the figure, the updated San Diego mechanism agrees much better with the experimental data than the previous mechanism, especially for pure NH 3 , where the previous San Diego mechanism overestimates ign by four orders of magnitude. Computations employing other mechanisms in the literature revealed less discrepancy between the new predictions and experiments than had been found for some others, [32][33][34][35] which were overreactive by amounts up to a factor of 5 under these conditions. These results provide strong support for the present revisions.…”

Section: Comparisons With Experimentsmentioning

confidence: 47%

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An updated short chemical‐kinetic nitrogen mechanism for carbon‐free combustion applications

et al. 2019

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Chemical-kinetic combustion mechanisms for hydrogen-oxygen-nitrogen systems, motivated originally by concerns about NO x emissions during hydrogen burning, have recently acquired renewed interest as a result of the possibility of employing ammonia-hydrogen mixtures in gas turbines and reciprocating engines as drop-in fuel to replace the use of natural gas. Specifically, this is of relevance to the implementation of engineering approaches for economical power generation with carbon sequestration or to large-scale energy-storage schemes, based on hydrogen or efficient hydrogen carriers such as ammonia. Because computational investigations are facilitated by short mechanisms (since the use of large mechanisms is often prohibitively expensive in reactive flow simulations), in response to the original concerns, a short nitrogen mechanism was developed in San Diego in the 1990s (not updated since 2004), without consideration of ammonia combustion. In view of the renewed interest in this topic, that mechanism has now been expanded to encompass 60 elementary steps among 19 reactive chemical species, including ammonia burning and NO x production, as reported herein, greatly improving predictions. With particular attention to high reactant temperatures and high-pressure conditions, relevant to industrial applications, it is shown that the present short mechanism retains satisfactory accuracy, exhibiting deviations that in most cases are within acceptable bounds (±20%). The revisions maintain the shortness of the original mechanism, adding only one more reactive species and six more elementary steps (while updating values of rate parameters of nine other steps, on the basis of newly available information). In addition, the short mechanism is applied herein to the analysis of fundamental combustion properties of ammonia/hydrogen/nitrogen-air laminar premixed flames, at unstrained and strained conditions, for comparison with methane-air flames as a reference gas-turbine fuel. It is found by comparing carbon-free and hydrocarbon laminar flames that these reactive mixtures, even if characterized by nearly identical adiabatic flame temperature and laminar flame speeds, nevertheless exhibit substantially different resistance to strain, with the ammonia/hydrogen flames exceeding the strain limit of methane flames by a factor of 5.

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Section: Comparisons With Experimentsmentioning

confidence: 47%

Section: Comparisons With Experimentsmentioning

confidence: 47%

An updated short chemical‐kinetic nitrogen mechanism for carbon‐free combustion applications

et al. 2019

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“…On the other hand, several experimental campaigns carried out in the latest years in less conventional conditions (lower temperatures, high dilution levels and wider pressure ranges) have shown that the fundamental knowledge of ammonia kinetics is still far from complete: the available mechanisms have shown important deviations in the autoignition behavior in diluted conditions, both in hightemperature shock tubes (ST) 27 and low-to intermediatetemperature shock tubes 32 and rapid compression machines (RCM). 33,34 Similarly, flow reactor experiments of pure NH 3 oxidation under atmospheric 35 and high pressure 36 showed that the kinetic models were not always able to reproduce the experimental trends. Da Rocha et al 37 showed the inadequacy of several kinetic mechanisms in predicting the laminar flame speed (LFS) of NH 3 , and most of them were shown to overpredict the actual rates.…”

Section: Introductionmentioning

confidence: 99%

An experimental, theoretical and kinetic-modeling study of the gas-phase oxidation of ammonia

et al. 2020

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“…Besides, N H 3 combustion is not completely understood and some experimental issues are still barriers or unresolved. According to some sources [13,17], N H 3 has been reported to adsorb on stainless steel surfaces, as to decompose on given materials [18,19]. Thus, providing new experimental data for N H 3 conversion under different combustion conditions, and assuring a reliable kinetic model for the H 2 /N O x system seems important for addressing N H 3 oxidation.…”

Section: Introductionmentioning

confidence: 99%

High pressure study of H oxidation and its interaction with NO

Colom-Díaz

Millera

Bilbao

et al. 2019

International Journal of Hydrogen Energy

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The present study deals with the oxidation of H 2 at high pressure and its interaction with N O. The high pressure behavior of the H 2 /N O x /O 2 system has been tested over a wide range of temperatures (500-1100 K) and different air excess ratios (λ= 0.5 -6.4). The experiments have been carried out in a tubular flow reactor at 10, 20 and 40 bar. N O has been found to promote H 2 oxidation under oxidizing conditions, reacting with HO 2 radicals to form the more active OH radical, which enhances the conversion of hydrogen. The onset temperature for hydrogen oxidation, when doped with N O, was approximately the same at all stoichiometries at high pressures (40 bar), and shifted to higher temperatures as the pressure decreases. The experimental results have been analyzed with an updated kinetic model. The reaction N O+N O+O 2 N O 2 +N O 2 has been found to be important at all conditions studied and its kinetic parameters have been modified, according to its activation energy uncertainty. Furthermore, the kinetic parameters of reaction HN O+H 2 N H+H 2 O have been estimated, in order to obtain a good prediction of the oxidation behavior of H 2 and N O conversion under reducing conditions. The kinetic model shows a good agreement between experimental results and model predictions over a wide range of conditions.

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Ammonia oxidation at high pressure and intermediate temperatures

Cited by 232 publications

References 66 publications

An updated short chemical‐kinetic nitrogen mechanism for carbon‐free combustion applications

An updated short chemical‐kinetic nitrogen mechanism for carbon‐free combustion applications

An experimental, theoretical and kinetic-modeling study of the gas-phase oxidation of ammonia

High pressure study of H oxidation and its interaction with NO

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