Kinetic Modeling of the Boosting Effects of NOx Addition on the Combustion of Ammonia and Ammonia/Hydrogen Mixtures

IFP Energies nouvelles (IFPEN) est un acteur majeur de la recherche et de la formation dans les domaines de l’énergie, du transport et de l’environnement. De la recherche à l’industrie, l’innovation technologique est au cœur de son action, articulée autour de quatre priorités stratégiques : Mobilité Durable, Energies Nouvelles, Climat / Environnement / Economie circulaire et Hydrocarbures Responsables.

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• l’apport de solutions aux défis sociétaux de l’énergie et du climat, en favorisant la transition vers une mobilité durable et l’émergence d’un mix énergétique plus diversifié ;
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Kinetic Modeling of the Boosting Effects of NOx Addition on the Combustion of Ammonia and Ammonia/Hydrogen Mixtures

Context

Ammonia is considered as a good hydrogen and energy carrier, and a promising solution for de-carbonization. However, the poor combustion characteristics of ammonia (e.g., high ignition energy, low flame speeds, and limited flammability) are obstructing it from becoming a feasible solution. Therefore, various technologies have been developed to boost ammonia combustion, such as blending of hydrogen, methane, diesel, and additives. Although these technologies show different boosting capabilities, they also impose new challenges such as higher NO_x emissions and introduction of CO₂ emissions.

• Therefore, it is necessary to advance the technology for boosting ammonia combustion.

One potential way is through the using of NO_x as boosting additives. Comparing to other additives, it is easy to obtain (abundant in the exhaust gas from the combustion of NH₃ and NH₃/H₂ mixtures) and could boost the combustion without introducing CO₂ emissions. The main composition of NO_x is mainly NO with NO₂, and N₂O. NO₂ is known the have high reactivity and could boost combustion through a "NO₂-NO" loop which generates OH radicals. Although NO is typically considered to be much less reactive, a recent study on the impact of NO_x addition on methane combustion found that NO acts as an inhibitor on ignition at low concentrations but become a promoter as NO concentrations increase in the mixture. These indicates that boosting ammonia combustion with NO_x addition could be of great potential.

• Currently, no study is available on this topic. Therefore, it is necessary and urgent to have a better understanding on the combustion chemistry of the NO_x boosting effect on ammonia combustion and develop corresponding technologies especially for large-scale applications such as industrial power plants and marine gas turbines.

Methodology

• Bibliography on ammonia combustion, existing technologies for boosting ammonia combustion, kinetic mechanisms for ammonia combustion, exhaust gas composition, and chemical kinetics of the boosting effect by NO_x addition.
• Kinetic modeling to model and compare their boosting effects of each identified technologies in terms of ignition delay times and laminar flame speeds.
• Kinetic modeling to model the boosting effect on ignition delay and flame speeds of ammonia and ammonia/hydrogen mixtures by the addition of NO, NO₂, N₂O, their mixtures and exhaust gas of ammonia combustion.
• Study the kinetics and analyze reaction pathways related to the NO_x boosting effects.
• (If previous results show feasibility) Propose corresponding technology for large-scale industrial applications.

What you could acquire after the internship

• knowledge on ammonia combustion and technologies for boosting ammonia combustion.
• Computational skills: kinetic modeling using the software CHEMKIN Pro.

Requested profile and skills:

Level: Bac+5 or Bac+4

• Aptitudes: Taste for research, dynamism and force of proposal, motivation for the valorization of results (writing of scientific articles), ability to work in a team

Duration and dates: 5 months between April and September 2023

Practical information: The internship will take place at IFP Energies nouvelles in Rueil-Malmaison (west of Paris). The intern will be granted with a financial compensation (unless granted otherwise).

Interested? Send a letter of motivation and a CV

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