Experimental and numerical studies on NOx emission characteristics in laminar non-premixed jet flames of ammonia-containing methane fuel with oxygen/nitrogen oxidizer

Woo, Mino; Choi, Byung Chul; Ghoniem, Ahmed F.

doi:10.1016/j.energy.2016.07.150

Cited by 38 publications

(7 citation statements)

References 32 publications

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“…In comparison to methane, non-premixed CH 4 /NH 3 /air flames showed much lower CO 2 emissions with moderate reduction of combustion stability limits and flame temperature . When the ammonia fraction is small in the fuel mixture, NO x emissions were found to be increased monotonically with the ratio of ammonia . Because methane–ammonia mixtures contain significant fuel-bound nitrogen, the addition of more NH 3 leads to higher N 2 concentrations rather than NO …”

Section: Combustionmentioning

confidence: 95%

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Review on Ammonia as a Potential Fuel: From Synthesis to Economics

et al. 2021

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Ammonia, a molecule that is gaining more interest as a fueling vector, has been considered as a candidate to power transport, produce energy, and support heating applications for decades. However, the particular characteristics of the molecule always made it a chemical with low, if any, benefit once compared to conventional fossil fuels. Still, the current need to decarbonize our economy makes the search of new methods crucial to use chemicals, such as ammonia, that can be produced and employed without incurring in the emission of carbon oxides. Therefore, current efforts in this field are leading scientists, industries, and governments to seriously invest efforts in the development of holistic solutions capable of making ammonia a viable fuel for the transition toward a clean future. On that basis, this review has approached the subject gathering inputs from scientists actively working on the topic. The review starts from the importance of ammonia as an energy vector, moving through all of the steps in the production, distribution, utilization, safety, legal considerations, and economic aspects of the use of such a molecule to support the future energy mix. Fundamentals of combustion and practical cases for the recovery of energy of ammonia are also addressed, thus providing a complete view of what potentially could become a vector of crucial importance to the mitigation of carbon emissions. Different from other works, this review seeks to provide a holistic perspective of ammonia as a chemical that presents benefits and constraints for storing energy from sustainable sources. State-of-the-art knowledge provided by academics actively engaged with the topic at various fronts also enables a clear vision of the progress in each of the branches of ammonia as an energy carrier. Further, the fundamental boundaries of the use of the molecule are expanded to real technical issues for all potential technologies capable of using it for energy purposes, legal barriers that will be faced to achieve its deployment, safety and environmental considerations that impose a critical aspect for acceptance and wellbeing, and economic implications for the use of ammonia across all aspects approached for the production and implementation of this chemical as a fueling source. Herein, this work sets the principles, research, practicalities, and future views of a transition toward a future where ammonia will be a major energy player.

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Section: Combustionmentioning

confidence: 95%

“…168 When the ammonia fraction is small in the fuel mixture, NO x emissions were found to be increased monotonically with the ratio of ammonia. 169 Because methane−ammonia mixtures contain significant fuel-bound nitrogen, the addition of more NH 3 leads to higher N 2 concentrations rather than NO. 170 .…”

Section: Combustionmentioning

confidence: 99%

Review on Ammonia as a Potential Fuel: From Synthesis to Economics

et al. 2021

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“…They found that in the CO 2 atmosphere, the fuel-NO formation is enhanced with the increase of OH/O ratio. Woo et al 25 examined the NO x production in the nonpremixed combustion of methane-ammonia. They found that ammonia enhances the NO formation in the internal layer but suppresses NO formation in the external layer of the jet flame.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Kinetic Study on the Oxidation of Syngas-Ammonia under Both N₂ and CO₂ Atmospheres in a Jet-Stirred Reactor

Ding

Wang

et al. 2021

Energy Fuels

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Although syngas combustion has been extensively investigated, previous studies did not systematically examine the fuel-NO x formation from ammonia-containing syngas in both N2 and CO2 atmospheres. Investigations on syngas-ammonia oxidation are significant for suppressing the fuel-NO x emission from the combustion of actual syngas containing NH3. This study presents new experimental results on syngas-ammonia oxidation under both N2 and CO2 atmospheres in a jet-stirred reactor. The effects of CO2 concentration (X CO2: 0–60%), temperature (T: 900–1400 K), equivalence ratio (Φ: 0.4–1.65), initial CH4 concentration (X CH4: 0–2000 ppm), CO/H2 ratio, and residence time (τ: 0.001–10 s) are investigated. For the oxidation of syngas-ammonia, the reactant consumption is delayed and more CO is produced in high CO2 concentration. A critical temperature to obtain the peak N2O production is found, and it is slightly reduced from 1000 to 950 K with Φ increasing from 0.63 to 1.25. Moreover, the N2O concentration is basically insensitive to the concentration of CH4 and the CO/H2 ratio in syngas. The NO production is enhanced with the increase of T, X CH4, and the CO/H2 ratio, while it is reduced with increasing Φ. Interestingly, the high concentration of CO2 suppresses the fuel-NO formation in fuel-lean conditions, while it significantly enhances the fuel-NO production in fuel-rich conditions. To minimize emissions of NO, N2O, and CO, it is recommended to operate the reaction at T > 1000 K and simultaneously avoid significantly high temperatures at the equivalence ratio of approximately 0.9, low values of initial CH4 concentration and the CO/H2 ratio (e.g., <1), long residence times (τ > 2 s), and high concentrations of CO2 (X CO2 > 30%). Furthermore, the numerical simulations agree well with the vast majority of measurements, and the dependence of NO on Φ at X CO2 = 30% is also well predicted. The present study provides new fundamental understandings of the fuel-NO x formation from ammonia-containing syngas.

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“…The stabilization issue was examined for premixed ammonia/air flame by Hayakawa et al (2017) in a swirl burner configuration, but fundamental aspects of ammonia and ammonia blend flames stabilization still need to be considered. Existing studies on ammonia or ammonia blends non-premixed jet flames remains limited (Sullivan et al, 2002;Woo et al, 2016), and mainly focus on the NOx emission issue. Deeper analysis and clarification of the ammonia blends stabilization process are thus required.…”

Section: Introductionmentioning

confidence: 99%

Study of the Combined Effect of Ammonia Addition and Air Coflow Velocity on a Non-premixed Methane Jet Flame Stabilization

Colson

Kühni

Galizzi

et al. 2020

Combustion Science and Technology

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Ammonia is a promising carbon-free fuel that can be used for CO2 reduction.However, ammonia industrial use presents challenges, including flame stabilization. In this study, a non-premixed methane-ammonia jet flame in an air coflow was considered to observe the effects of ammonia addition on conventional fuels flame stabilization. First, the effects of the introduction of ammonia on the stabilization regimes of the methane jet flame were studied.Then the coupled effects of the variation in ammonia concentration and air coflow velocity on flame stabilization were investigated. In the present jet configuration, a sharp reduction of the stabilization domain was observed with ammonia addition: the liftoff and re-attachment velocities were obtained for mixtures of up to 50% of ammonia in the fuel, a ratio above which the flame could not be stabilized. When increasing the coflow velocity, a sudden drop in the re-attachment velocity occurred for methane/ammonia flames. This reattachment drop was associated with an increase in the height of the lifted flame when the jet velocity decreases before re-attachment, for large enough coflow velocity and ammonia concentration. A critical height above which the lifted flames all present the same ascending behavior could be defined and characterizes this peculiar phenomenon.

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Experimental and numerical studies on NOx emission characteristics in laminar non-premixed jet flames of ammonia-containing methane fuel with oxygen/nitrogen oxidizer

Cited by 38 publications

References 32 publications

Review on Ammonia as a Potential Fuel: From Synthesis to Economics

Review on Ammonia as a Potential Fuel: From Synthesis to Economics

Experimental and Kinetic Study on the Oxidation of Syngas-Ammonia under Both N₂ and CO₂ Atmospheres in a Jet-Stirred Reactor

Study of the Combined Effect of Ammonia Addition and Air Coflow Velocity on a Non-premixed Methane Jet Flame Stabilization

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Experimental and numerical studies on NOx emission characteristics in laminar non-premixed jet flames of ammonia-containing methane fuel with oxygen/nitrogen oxidizer

Cited by 38 publications

References 32 publications

Review on Ammonia as a Potential Fuel: From Synthesis to Economics

Review on Ammonia as a Potential Fuel: From Synthesis to Economics

Experimental and Kinetic Study on the Oxidation of Syngas-Ammonia under Both N2 and CO2 Atmospheres in a Jet-Stirred Reactor

Study of the Combined Effect of Ammonia Addition and Air Coflow Velocity on a Non-premixed Methane Jet Flame Stabilization

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Experimental and Kinetic Study on the Oxidation of Syngas-Ammonia under Both N₂ and CO₂ Atmospheres in a Jet-Stirred Reactor