Experimental and kinetic modeling study of NO formation in premixed CH4+O2+N2 flames

Han, Xinlu; Lavadera, Marco Lubrano; Brackmann, Christian; Wang, Zhihua; He, Yong; Konnov, Alexander A.

doi:10.1016/j.combustflame.2020.10.010

Cited by 42 publications

(4 citation statements)

References 68 publications

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“…It should be noted that, although several chemical kinetic mechanisms for NH 3 and NH 3 /hydrocarbon combustion are available in the literature (e.g. refs , , , and − ), most of them were built to predict the combustion behavior of hydrocarbons over the C 1 –C 3 range; therefore, they are not applicable for the present comparison, where n -heptane and iso-octane have been used. On the other hand, some comprehensive chemical mechanisms for the combustion of n -heptane, iso-octane, and mixtures of both exist in the literature, but they have not been expanded to include NH 3 modeling capability.…”

Section: Experimental and Numerical Toolsmentioning

confidence: 99%

Comparative Effect of Ammonia Addition on the Laminar Burning Velocities of Methane, n-Heptane, and Iso-octane

2020

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Adiabatic laminar burning velocities for methane, n-heptane, and iso-octane blended with ammonia were experimentally determined using the heat flux method. The flames were stabilized at atmospheric pressure and at an initial temperature of 338 K, over equivalence ratios ranging from 0.7 to 1.4 and ammonia blending fractions in the binary fuel mixtures from 0 to 90%. These experiments are essential for the development, validation, and optimization of chemical kinetic models, e.g., for the combustion of gasoline−ammonia fuel mixtures. It was observed that the addition of ammonia to methane, n-heptane, and isooctane leads to a decrease in the laminar burning velocity that is not proportional to the ammonia mole fraction. In addition, ammonia has the same impact on the burning velocities of n-heptane and iso-octane but a slightly higher effect on those of methane. Such a burning velocity reduction is due to synergistic thermal, kinetic, and indirect transport effects. New experimental results were compared to predictions of the POLIMI detailed chemical kinetic mechanism. An overall good agreement between the measurements and simulated results was observed for the laminar burning velocities over the equivalence ratio and ammonia fraction ranges investigated.

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Section: Experimental and Numerical Toolsmentioning

confidence: 99%

Comparative Effect of Ammonia Addition on the Laminar Burning Velocities of Methane, n-Heptane, and Iso-octane

2020

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“…The impact of rate constants for the most sensitive reactions in ammonia self-ignition and flame propagation of NH 3 + O 2 and H 2 + N 2 O blends were considered in the study. Their detailed model has been improved based on [46,47]. The thermodynamic data of nitrogen-based species have been selected from the database of Burcat and Rusicc [48].…”

Section: The Investigated Kinetic Modelsmentioning

confidence: 99%

Experimental and numerical analyses of nitrogen oxides formation in a high ammonia-low hydrogen blend using a tangential swirl burner

et al. 2022

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Ammonia has been considered as a novel fuel for decarbonization purposes. However, emissions from combustion systems are still posing a problem. Therefore, experimental and numerical simulations have been conducted to study the concentration of exhaust emissions (Nitric oxide “NO”, Nitrous oxide “N2O”) from burning the ammonia/hydrogen (NH3/H2) blend 85/15 (vol%). The effects were measured at various thermal powers ranging 10 to 20 kW and with different Reynolds numbers from 20,000—40,000. The experimental points were numerically investigated in the Ansys CHEMKIN-Pro environment employing seven chemical kinetic mechanisms taken from the literature. All experiments have been undertaken at standard atmospheric conditions. The experimental results showed that both NO and N2O gradually increased when the Reynolds number increased from 20,000 to 40,000. Along with that, the concentration of NO emissions at the exhaust reported minimum level when the Re = 20,000 due to lower reactivity radical formation, all that led to a deterioration of the flame characteristics. Also, the integrated radical intensities of NO*, OH*, NH*, and NH2* demonstrate an increasing trend as Re increased from 20,000 to 40,000. In terms of thermal power, N2O suffered an abrupt decrease when the thermal power increased up to 15 kW, while the opposite occurs for NO. In addition, the radicals intensity of OH*, NH*and NH2* figures show an increase in their concentration when the thermal power increased up to 15 kW then decreased with increasing thermal intensity to reach 20 kW, reflecting into increased NO productions and decreased N2O levels. The numerical analysis showed that Stagni, Bertolino, and Bowen Mei were the most accurate mechanisms as these give a good prediction for NO and N2O. The study also showed that the chemical reaction (HNO + O2 ↔ NO + HO2) is the main source of NO formation. While the chemical reaction (NH + NO ↔ N2O + H) is responsible for the formation of N2O by consuming NO and when there will be abundance in NH radicals. Finally, dealing with a blended fuel of high ammonia concentration encourages ammonia chemistry to become more dominant in the flame. It decreases the flame temperature, hence lowering heat loss between the flame and the surrounding.

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“…5 In addition, NH 3 is a promising energy carrier due to its lower cost per unit of stored energy and higher-volume energy density compared with hydrogen, stable and cost-effective production, and fully developed infrastructures. 1,6,7 Chehade and Dincer 1 indicated that NH 3 has great potential for applications in internal combustion engines, gas turbines, rockets, and furnaces. Kurata et al 8 successfully achieved the first NH 3 /air combustion power generation using a micro gas turbine.…”

Section: Introductionmentioning

confidence: 99%

“…The most widely used process to produce NH 3 today is the Haber–Bosch process invented in 1908, − which is responsible for 1.4% of global CO 2 emissions . In addition, NH 3 is a promising energy carrier due to its lower cost per unit of stored energy and higher-volume energy density compared with hydrogen, stable and cost-effective production, and fully developed infrastructures. ,, Chehade and Dincer indicated that NH 3 has great potential for applications in internal combustion engines, gas turbines, rockets, and furnaces. Kurata et al .…”

Section: Introductionmentioning

confidence: 99%

Explosion Characteristics of NH₃/CH₃OH/Air Mixtures

et al. 2022

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In this work, the explosive combustion of NH3/CH3OH/air mixtures covering wide ranges of equivalence ratios (0.7–1.7) and CH3OH mole fractions (0.2–1.0) was investigated experimentally and theoretically at ambient temperature and pressure. Results showed that the addition of CH3OH increases the maximum explosion pressure and maximum pressure rise rate. The empirical correlations for the maximum explosion pressure and maximum pressure rise rate are proposed, respectively. Furthermore, the heat loss of the explosion decreases significantly with the increasing CH3OH mole fraction. According to the instability analysis, the tendency of flame instability is enhanced with the enrichment of CH3OH due to the promoted hydrodynamic instability. Besides, the maximum pressure rise rate is augmented by flame instability. Kinetic analysis indicates that the CH3OH addition enhances the net heat release rate and active radicals. The total heat release of the NH3/CH3OH/air explosion is mainly attributed to the reactions R3: OH + H2 ⇔ H + H2O, R11: HO2 + H ⇔ 2OH, R24: CO + OH ⇔ CO2 + H, and R284: NH3 + H = NH2 + H2, while the predominant endothermal reaction is R1: H + O2 ⇔ O + OH. With the addition of CH3OH, the chemical effect has the largest contributions to the accelerated flame propagation on the lean and stoichiometric side, while the contributions of thermal and transport effects are dominant on the rich side.

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Experimental and kinetic modeling study of NO formation in premixed CH4+O2+N2 flames

Cited by 42 publications

References 68 publications

Comparative Effect of Ammonia Addition on the Laminar Burning Velocities of Methane, n-Heptane, and Iso-octane

Comparative Effect of Ammonia Addition on the Laminar Burning Velocities of Methane, n-Heptane, and Iso-octane

Experimental and numerical analyses of nitrogen oxides formation in a high ammonia-low hydrogen blend using a tangential swirl burner

Explosion Characteristics of NH₃/CH₃OH/Air Mixtures

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Experimental and kinetic modeling study of NO formation in premixed CH4+O2+N2 flames

Cited by 42 publications

References 68 publications

Comparative Effect of Ammonia Addition on the Laminar Burning Velocities of Methane, n-Heptane, and Iso-octane

Comparative Effect of Ammonia Addition on the Laminar Burning Velocities of Methane, n-Heptane, and Iso-octane

Experimental and numerical analyses of nitrogen oxides formation in a high ammonia-low hydrogen blend using a tangential swirl burner

Explosion Characteristics of NH3/CH3OH/Air Mixtures

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Explosion Characteristics of NH₃/CH₃OH/Air Mixtures