Measurement and modelling of the laminar burning velocity of methane-ammonia-air flames at high pressures using a reduced reaction mechanism

Okafor, Ekenechukwu C.; Naito, Yuji; Colson, Sophie; Ichikawa, Akinori; Kudo, Taku; Hayakawa, Akihiro; Kobayashi, Haruo

doi:10.1016/j.combustflame.2019.03.008

Cited by 368 publications

(153 citation statements)

References 88 publications

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“…provided another dataset for ammonia blended with methane (CH4) in air (up to 53 vol.%NH3 in the fuel) at various , 298K and up to 0.5MPa [8]. Recently, Lhuillier et al attempted to partially fill in that gap with an extensive experimental LBV study by means of the outwardly propagating spherical flame (OPSF) method covering a wide range of (0.8 to 1.4), fuel hydrogen fractions (0 to 60 vol.%)…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation on ammonia combustion behavior in a spark-ignition engine by means of laminar and turbulent expanding flames

Lhuillier

Bréquigny

Contino³

et al. 2021

Proceedings of the Combustion Institute

110

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Ammonia combustion appears as a meaningful way to retrieve stored amounts of excess variable renewable energy, and the spark-ignition (SI) engine has been proposed as a practical conversion system. The present work aims at elucidating the combustion characteristics of ammonia blends in engine-relevant turbulent conditions. To that end, laminar and turbulent flame experiments were conducted in a constant-volume vessel at engine-relevant conditions of 445 K and 0.54 MPa to assess the combustion behavior of ammonia/hydrogen/air, ammonia/methane/air and methane/hydrogen/air mixtures observed in an all-metal single-cylinder SI engine. Results show that the respective accelerating or decelerating effects of hydrogen or methane enrichment observed in the SI engine could not be sufficiently explained by the laminar burning velocities of the mixtures. Since the latter are very low, the studied combustion regimes are at the boundary between the thin and broken reaction zones regimes, and thus strongly influenced by flame-turbulence interactions. The quantification of the flame response to turbulence shows much higher effects for ammonia blends, than for methane-based fuels.The aforementioned opposite effects of ammonia enrichment with hydrogen or methane are observed on the turbulent burning velocity during the turbulent flame experiments and correlated to the thermochemical properties of the reactants and the flame sensitivity to stretch. The latter may explain an unexpected bending effect on the turbulent-to-laminar velocity ratio when increasing the hydrogen fraction in the ammonia/hydrogen blend. Nevertheless, a very good correlation of the turbulent velocity was found with the Karlovitz and Damköhler numbers, that suggests that ammonia combustion in SI engines may be described following the usual turbulent combustion models. This encourages further investigations on ammonia combustion for the optimization of practical systems, by means of dedicated experiments and numerical simulations.

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Section: Introductionmentioning

confidence: 99%

Experimental investigation on ammonia combustion behavior in a spark-ignition engine by means of laminar and turbulent expanding flames

Lhuillier

Bréquigny

Contino³

et al. 2021

Proceedings of the Combustion Institute

110

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“…Hence, additional fuels such as hydrogen and natural gas have been suggested as combustion promotors. [3][4][5][6][7] If ammonia is cocombusted with methane, it is likely that methylamine is formed as an intermediate in significant amounts, primarily through the reaction 8,9 CH 3 + NH 2 + M ⇌ CH 3 NH 2 + M.…”

Section: Introductionmentioning

confidence: 99%

“…The poor combustion characteristics of NH

_{3}

are difficult to overcome in conventional engine combustion. Hence, additional fuels such as hydrogen and natural gas have been suggested as combustion promotors 3–7 . If ammonia is cocombusted with methane, it is likely that methylamine is formed as an intermediate in significant amounts, primarily through the reaction 8, 9

{normalCH}_{3} + {normalNH}_{2} + M ⇌ {normalCH}_{3} {normalNH}_{2} + M .

Mendiara and Glarborg 9 reported CH

_{3}

_{2}

to be a significant intermediate in flow reactor oxidation of CH

_{4}

/NH

_{3}

mixtures.…”

Section: Introductionmentioning

confidence: 99%

Oxidation of methylamine

Glarborg

Andreasen

Hashemi

et al. 2020

Int J of Chemical Kinetics

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A detailed chemical kinetic model for oxidation of methylamine has been developed, based on theoretical work and a critical evaluation of data from the literature. The rate coefficients for the reactions of CH 3 NH 2 + O 2 → CH 2 NH 2 / CH 3 NH + HO 2 , CH 3 NH 2 + H → CH 3 + NH 3 , CH 3 NH → CH 2 NH 2 , and CH 3 NH + O 2 → CH 2 NH + HO 2 were calculated from ab initio theory. The mechanism was validated against experimental results from batch reactors, flow reactors, shock tubes, and premixed flames. The model predicts satisfactorily explosion limits for CH 3 NH 2 and its oxidation in a flow reactor. However, oxidation in the presence of nitric oxide, which strongly promotes reaction at lower temperatures, is only described qualitatively. Furthermore, calculated flame speeds are higher than reported experimental values; the model does not capture the inhibiting effect of the NH 2 group in CH 3 NH 2 compared to CH 4. More work is desirable to confirm the products of the CH 3 NH + NO reaction and to look into possible pathways to NH 3 in methylamine oxidation.

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“…In other experimental research activities, results regarding flame characteristics for ammonia-methane co-firing [70][71][72][73][74][75], ammonia-hydrogen co-firing [76][77][78][79], and ammoniasyngas co-firing [80] have been reported, respectively. As a common opinion, it was reported that the ignition characteristics and flame velocity were improved when gas fuel with a higher reactivity than ammonia was mixed.…”

Section: Effect Of Ammonia-hydrogen and -Methane Mixture On The Combustion Characteristicsmentioning

confidence: 99%

Recent Advances in Ammonia Combustion Technology in Thermal Power Generation System for Carbon Emission Reduction

Lee

2021

Energies

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With the formation of an international carbon-neutral framework, interest in reducing greenhouse gas emissions is increasing. Ammonia is a carbon-free fuel that can be directly combusted with the role of an effective hydrogen energy carrier, and its application range is expanding. In particular, as research results applied to power generation systems such as gas turbines and coal-fired power plants have been reported, the technology to use them is gradually being advanced. In the present study, starting with a fundamental combustion research case conducted to use ammonia as a fuel, the application research case for gas turbines and coal-fired power plants was analyzed. Finally, we report the results of the ammonia-air burning flame and pulverized coal-ammonia-air co-fired research conducted at the authors’ research institute.

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Measurement and modelling of the laminar burning velocity of methane-ammonia-air flames at high pressures using a reduced reaction mechanism

Cited by 368 publications

References 88 publications

Experimental investigation on ammonia combustion behavior in a spark-ignition engine by means of laminar and turbulent expanding flames

Experimental investigation on ammonia combustion behavior in a spark-ignition engine by means of laminar and turbulent expanding flames

Oxidation of methylamine

Recent Advances in Ammonia Combustion Technology in Thermal Power Generation System for Carbon Emission Reduction

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