Propagation and emissions of premixed methane-ammonia/air flames

Ku, Jae Won; Ahn, Yeong Jong; Kim, H.K.; Kim, Y.H.; Kwon, Oh Chae

doi:10.1016/j.energy.2020.117632

Cited by 34 publications

(17 citation statements)

References 21 publications

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“…Since the 1950s, fundamental investigations have been performed to understand the combustion characteristics of ammonia. The experiments include the flammability, − ignition delay, − , flame propagation, − and speciation. − Data from those experiments serve further as validation targets for the chemical kinetics mechanisms and as references for further technical realizations. It is therefore essential here to provide a review of the measurements, which are easily accessible to peer researchers for identifying the relevant and reliable data set.…”

Section: Combustionmentioning

confidence: 99%

“…In section , the reported experimental investigations were discussed, focusing on low to intermediate temperatures and elevated pressures. In addition to the comprehensive experimental data sets available in the literature, ,,,− ,,,,,− ,− ,,− ,,,− quite a few reaction mechanisms have been reported in the past 5 years. ,,,,,,,− However, in general, these mechanisms have been evaluated only against a limited subset of the experimental data. In the present review, selected recent models are evaluated against experimental investigations for neat ammonia, ammonia–hydrogen mixtures, and ammonia–hydrocarbon mixtures.…”

Section: Combustionmentioning

confidence: 99%

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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: 99%

Section: Combustionmentioning

confidence: 99%

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

et al. 2021

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“…In contrast, as the burning velocity decreases as the pressure increases, additional means are required to design a combustion operated machine under high pressure conditions, such as a gas turbine. As shown in Figure 10, Ku et al investigated the combustion characteristics of expanding spherical premixed methane-ammonia-air flames [64]. The premixed methaneammonia-air flames produced less CO2; however, the flames became thicker and propagated slower than the pure methane-air flames.…”

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

confidence: 99%

“…However, NOx increased because of the fuel-NOx mechanism, which was found to be more dominant than the potential NOx reduction with reduced flame temperature, resulting in the maximum values of the NOx mole fraction. As shown in Figure 10, Ku et al investigated the combustion characteristics of expanding spherical premixed methane-ammonia-air flames [64]. The premixed methaneammonia-air flames produced less CO 2 ; however, the flames became thicker and propagated slower than the pure methane-air flames.…”

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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“…These studies provided valuable insights into the flames' structure and developed the mixture's thermochemical process. Ku et al, 17 Okafor et al, 18 and Filipe Ramos et al 19 have done experimental and numerical studies on CH 4 ‐NH 3 ‐air premixed flames. They have investigated the potential use of premixed NH 3 ‐CH 4 mixtures as low hydrocarbon feedstock and found high nitrogen oxide emittances in the current flame design.…”

Section: Introductionmentioning

confidence: 99%

Oxy‐ and air‐ammonia premixed combustion in a two‐inlet cyclone combustor

Bektaş¹

2022

Intl J of Energy Research

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Summary Many scientists have received significant attention since ammonia comprises a carbon‐free chemical and could be derived from renewable hydrogen and air‐separated nitrogen. Most of them think it could be an alternative fuel rather than methane in a cyclonic burner. The main goal of this study is to investigate the possible ways of using ammonia as a clean and sustainable fuel. For this purpose, we first investigated the premixed oxy‐ammonia combustion behaviour using a two‐inlet cyclone combustor. Then, the findings values are compared with the combustion performance of air‐ammonia and air‐methane combustion. Cyclone combustors provide improved mixing quality and longer combustion residence time. The computational fluid dynamics (CFD) simulation was used in this study to estimate the temperature and emissions levels. The findings demonstrate that the highest predicted temperature values of oxy‐ammonia combustion (1828 K) are higher than air‐methane (1538 K) and air‐ammonia combustion (994 K). In addition, NOx emissions have been predicted by post‐processing the CFD code used in this study. According to predicted NOx levels, oxygen usage as an oxidizer rather than air significantly influences NOx emission levels due to thermal and fuel NOx mechanisms. The NOx levels of stoichiometric combustion are higher than the fuel‐rich combustion in all cases. Besides, the lowest NO emission levels are predicted under fuel‐rich conditions of ammonia at the combustor outlet. It is also determined that while the highest axial velocity values occur in the flame regions, ammonia's highest laminar burning velocity is achieved under the fuel‐rich states with Ø = 1.1 for oxy‐ammonia. Therefore, it is concluded that oxy‐ammonia combustion has a more significant combustion performance than air‐methane combustion with the robust whirling flow, sound mixing, and combustion structure.

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Propagation and emissions of premixed methane-ammonia/air flames

Cited by 34 publications

References 21 publications

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

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

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

Oxy‐ and air‐ammonia premixed combustion in a two‐inlet cyclone combustor

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