Effects of ammonia substitution on combustion stability limits and NOx emissions of premixed hydrogen–air flames

Joo, Jin Deok; Lee, Seungro; Kwon, Oh Chae

doi:10.1016/j.ijhydene.2012.01.059

Cited by 71 publications

(22 citation statements)

References 15 publications

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“…On the other hand, if ammonia can be directly combusted as a fuel in a more conventional large-scale thermal power plant, it would not take much time be begin utilizing ammonia as an energy source. Recently, various fundamental studies have been conducted on the laminar burning velocity [18][19][20][21][22][23][24], explosion behavior [25], chemical kinetics [26][27][28][29][30][31][32], extinction characteristics [33], effects of plasma [34], and stabilization of turbulent ammonia/air flame [35]. Previous researches showed that the laminar burning velocity of ammonia is much lower than that of general hydrocarbon fuels, such as methane and propane.…”

Section: Introductionmentioning

confidence: 99%

“…Previous researches showed that the laminar burning velocity of ammonia is much lower than that of general hydrocarbon fuels, such as methane and propane. Although the laminar flame propagation characteristics of ammonia/air mixtures have been investigated in many studies [18][19][20][21][22][23][24], the turbulent flame propagation characteristics of ammonia/air mixture have yet to be extensively investigated. For the efficient development of gas turbines that use ammonia as a fuel, the flame propagation characteristics in the turbulent field, which is different from that in the laminar flow field, must be investigated in detail.…”

Section: Introductionmentioning

confidence: 99%

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Extinction limits of an ammonia/air flame propagating in a turbulent field

Ichimura

Hadi

Hashimoto

et al. 2019

Fuel

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Ammonia, which does not emit carbon dioxide even when it is burned, is expected as a new carbon-free fuel to replace coal and natural gas used in thermal power plant. However, the turbulent flame propagation characteristics have yet to be extensively investigated. This study aimed to clarify the extinction limits of ammonia/air flame in turbulent fields. To achieve this aim, the spherical flame propagation experiments using a fan-stirred constant volume vessel were conducted.The results revealed the unique feature of extinction limit of ammonia in a turbulent field. The ammonia/air mixture with a 0.9 equivalence ratio can propagate at the highest turbulence intensity even though the laminar burning velocity reaches a maximum around an equivalence ratio of 1.1. The fuel-lean mixture can propagate at high turbulence intensity because of the effect of Lewis number. For a lean ammonia/air mixture that has a Lewis number smaller than unity, the local burning velocity increases by the diffusional-thermal instability. On the other hand, the local burning velocity in rich ammonia/air mixtures with a Lewis number larger than unity did not increase in the turbulent field, and the flame was easily extinguished. Because of the diffusional-thermal instability, the turbulence Karlovitz number at the flame extinction limit increases as the Markstein number decreases. The obtained findings from this study can contribute to the optimal design of gas turbines fueled by ammonia as well as the safety use of ammonia.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Extinction limits of an ammonia/air flame propagating in a turbulent field

Ichimura

Hadi

Hashimoto

et al. 2019

Fuel

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“…Furthermore, the combustion of H 2 -NH 3 mixtures is much more attractive with further beneficial characteristics of enhancing H 2 combustion safety and making H 2 flames visually detectable. Combustion of NH 3 and H 2 mixtures makes H 2 utilization easily controllable and diminishes the associated safety problems [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Study on using hydrogen and ammonia as fuels: Combustion characteristics and NO_xformation

Jun

Huang

Kobayashi

et al. 2014

Int. J. Energy Res.

324

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SUMMARYThis paper evaluates the potential of hydrogen (H2) and ammonia (NH3) as carbon‐free fuels. The combustion characteristics and NOx formation in the combustion of H2 and NH3 at different air‐fuel equivalence ratios and initial H2 concentrations in the fuel gas were experimentally studied. NH3 burning velocity improved because of increased amounts of H2 atom in flame with the addition of H2. NH3 burning velocity could be moderately improved and could be applied to the commercial gas engine together with H2 as fuels. H2 has an accelerant role in H2–NH3–air combustion, whereas NH3 has a major effect on the maximum burning velocity of H2–NH3–air. In addition, fuel‐NOx has a dominant role and thermal‐NOx has a negligible role in H2–NH3–air combustion. Thermal‐NOx decreases in H2–NH3–air combustion compared with pure H2–air combustion. NOx concentration reaches its maximum at stoichiometric combustion. Furthermore, H2 is detected at an air‐fuel equivalence ratio of 1.00 for the decomposition of NH3 in flame. Hence, the stoichiometric combustion of H2 and NH3 should be carefully considered in the practical utilization of H2 and NH3 as fuels. H2 as fuel for improving burning performance with moderate burning velocity and NOx emission enables the utilization of H2 and NH3 as promising fuels. Copyright © 2014 John Wiley & Sons, Ltd.

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“…However, the blow-off limits increase more sharply than the flashback limits, indicating that the former is more sensitive to fuel composition than the latter and thus showing an effect of widening the stable operating range of the SRB for enhanced /. This observation was somewhat expected since similar tendencies are observed for porous radiant burners with no external heat recirculation [14] and tube type gas burners [15]. The / limit where the flashback and blow-off limits are merged is estimated to be around 0.25, which is considered to be substantially extended compared with the limits for conventional porous radiant burners having a configuration and dimensions similar to the present SRB since preheated air is supplied to the burner inlet for the SRB while ambient air at normal temperature for the conventional porous burners.…”

Section: Combustion Stability Limits and Temperature Distribution In Srbmentioning

confidence: 56%

Experiment on superadiabatic radiant burner with augmented preheating

Kim

Vandadi

et al. 2015

Applied Energy

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Effects of ammonia substitution on combustion stability limits and NOx emissions of premixed hydrogen–air flames

Cited by 71 publications

References 15 publications

Extinction limits of an ammonia/air flame propagating in a turbulent field

Extinction limits of an ammonia/air flame propagating in a turbulent field

Study on using hydrogen and ammonia as fuels: Combustion characteristics and NO_xformation

Experiment on superadiabatic radiant burner with augmented preheating

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Effects of ammonia substitution on combustion stability limits and NOx emissions of premixed hydrogen–air flames

Cited by 71 publications

References 15 publications

Extinction limits of an ammonia/air flame propagating in a turbulent field

Extinction limits of an ammonia/air flame propagating in a turbulent field

Study on using hydrogen and ammonia as fuels: Combustion characteristics and NOxformation

Experiment on superadiabatic radiant burner with augmented preheating

Contact Info

Product

Resources

About

Study on using hydrogen and ammonia as fuels: Combustion characteristics and NO_xformation