High pressure oxidation of NH<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si3.svg"><mml:msub><mml:mrow/><mml:mn>3</mml:mn></mml:msub></mml:math>/<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si9.svg"><mml:mi>n</mml:mi></mml:math>-heptane mixtures

Thorsen, Lauge Sven; Jensen, Malene Stryhn Thestrup; Pullich, Mille Stub; Christensen, Jakob Munkholt; Hashemi, Hamid; Glarborg, Peter; Алексеев, В. А.; Nilsson, Erik; Wang, Ziyu; Mei, Bowen; Liu, Ning; Ju, Yiguang

doi:10.1016/j.combustflame.2023.112785

Cited by 31 publications

(11 citation statements)

References 64 publications

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“…In terms of NO x emissions, Shrestha et al give higher values during the ignition phase for NO and NO 2 compared to the other mechanisms, while all mechanisms show peak concentrations in the temperature range around 2500 K. Based on these findings, NO x concentrations could be lower during the ignition phase employing another mechanism. N 2 O concentrations follow similar trends and values for both Shrestha et al and Thorsen et al, while Xu et al show a single peak and deviate from the other mechanisms. Wang et al .…”

Section: Verificationsupporting

confidence: 65%

“…A half-circle trend similar to that in the reference case is assumed for equivalence ratios lower than 0.1. Besides this behavior, the NO limits in the present study were located at slightly lower equivalence ratios than the reference study, possibly due to the present study's use of a Δϕ of 0.25, compared to Kitamura et al's 42 Δϕ = 0.5. , 48 Thorsen et al, 57 Wang et al, 58 The mechanism applied in this work has shown its ability to reproduce reliable NO concentrations both for n-heptane oxidation in a jet-stirred rector 48 and for a fuel-rich ammoniahydrogen oxidation in a burner-stabilized flame. 52 Furthermore, given its ability to reproduce the work of Kitamura et al, 42 the calculations of the present study are expected to produce reasonable results with respect to NO.…”

Section: Verificationmentioning

confidence: 83%

“…NO, NO 2 , N 2 O, and C 2 H 2 concentrations for case 3 computed with four different mechanisms; Shrestha et al, Thorsen et al, Wang et al, Xu et al NO, NO 2 , and N 2 O concentrations are gathered for ϕ = 1.1, while C 2 H 2 is obtained at ϕ = 6.…”

Section: Verificationmentioning

confidence: 99%

“…42 Soot formation is primarily observed at higher equivalence ratios; hence, an equivalence ratio of 6 is chosen for the comparison of acetylene, while for NO, NO 2 , and N 2 O, an equivalence ratio of 1.1 is selected. Figure 4 displays the comparison with the four mechanisms: Shrestha et al 48 (402 species and 2543 reactions), Thorsen et al 57 (1369 species and 6314 reactions), Wang et al 58 (74 species and 495 reactions), and Xu et al 59 (69 species and 389 reactions).…”

Section: Verificationmentioning

confidence: 99%

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Ammonia in Dual-Fueled Internal Combustion Engines: Impact on NO_x, N₂O, and Soot Formation

Pedersen,

Lewandowski,

Schulze-Netzer

et al. 2023

Energy Fuels

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The combustion of ammonia in internal combustion engines (ICE) releases nitrogen-related exhaust emissions. Numerous studies have shown that the increased formation of nitrous oxide (N 2 O) may offset ammonia's carbon-free advantages, leading to a higher greenhouse gas potential than fossil fuels. Moreover, nitrogen contained in ammonia further promotes an increase in NO x formation. This study aims to expand the understanding of emission formation in dual-fuel ICEs when using ammonia as a fuel. By constant-pressure reactor simulations coupled with detailed reaction kinetics, the concept of equivalence ratio−temperature diagrams was employed to characterize conditions featuring high NO x , N 2 O, and soot concentrations. The diagrams were obtained for pure ammonia, pure n-heptane, and three blends with ammonia energy shares (AES) of 20, 50, and 80%. Our findings strengthen the perception that high concentrations of N 2 O in ICEs are related to incomplete combustion. A higher AES leads to increased N 2 O concentration during the ignition, going from single-digit ppm levels for pure n-heptane to conditions featuring levels 3 orders of magnitude higher for pure ammonia. In fully burned mixtures, N 2 O emissions feature a low fuel dependency and single-digit concentration levels only at low equivalence ratios and high temperatures. Further, varying contributions from the fuel NO, prompt NO, and thermal De-NO x mechanisms were observed with fuel composition; however, the thermal NO contribution led to a fuel-independent behavior for NO x emissions at temperatures above 2600 K. The soot concentration decreases as the carbon content in the fuel decreases. In our configuration, the lowest equivalence ratio at which the 0.1% soot yield limit was observed was 2.20 for pure n-heptane, 2.65 for AES of 20%, 5.05 for 50% AES, and not attained for higher AES. Ultimately, it was found that in fuel-rich regimes and at fully burned conditions, low concentrations of NO x and N 2 O emissions are observed.

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Section: Verificationsupporting

confidence: 65%

Section: Verificationmentioning

confidence: 83%

Section: Verificationmentioning

confidence: 99%

Section: Verificationmentioning

confidence: 99%

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Ammonia in Dual-Fueled Internal Combustion Engines: Impact on NO_x, N₂O, and Soot Formation

Pedersen,

Lewandowski,

Schulze-Netzer

et al. 2023

Energy Fuels

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“…Figure 19 compares predicted ignition delay times for fuel mixtures of NH 3 /H 2 , NH 3 /n-heptane, and NH 3 /H 2 /nheptane under stoichiometric conditions. The n-heptane subset in the model was drawn from Zhang et al, 90 while the subset describing amine/n-heptane interactions was adopted from Thorsen et al 91 The results show that both H 2 and n-heptane strongly promote the ignition of NH 3 . In a large 2-stroke diesel engine, the ignition conditions involve temperatures and pressures of roughly 900 K and 100 atm.…”

Section: Analysis and Further Validationmentioning

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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Ignition enhancement and NO formation of NH3/air mixtures by non-equilibrium plasma discharge

Mao,

Zhong,

Liu

et al. 2024

Combustion and Flame

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High pressure oxidation of NH3/n-heptane mixtures

Cited by 31 publications

References 64 publications

Ammonia in Dual-Fueled Internal Combustion Engines: Impact on NO_x, N₂O, and Soot Formation

Ammonia in Dual-Fueled Internal Combustion Engines: Impact on NO_x, N₂O, and Soot Formation

Flow Reactor Oxidation of Ammonia–Hydrogen Fuel Mixtures

Ignition enhancement and NO formation of NH3/air mixtures by non-equilibrium plasma discharge

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High pressure oxidation of NH3/n-heptane mixtures

Cited by 31 publications

References 64 publications

Ammonia in Dual-Fueled Internal Combustion Engines: Impact on NOx, N2O, and Soot Formation

Ammonia in Dual-Fueled Internal Combustion Engines: Impact on NOx, N2O, and Soot Formation

Flow Reactor Oxidation of Ammonia–Hydrogen Fuel Mixtures

Ignition enhancement and NO formation of NH3/air mixtures by non-equilibrium plasma discharge

Contact Info

Product

Resources

About

Ammonia in Dual-Fueled Internal Combustion Engines: Impact on NO_x, N₂O, and Soot Formation

Ammonia in Dual-Fueled Internal Combustion Engines: Impact on NO_x, N₂O, and Soot Formation