Perspectives on NO Emissions and Impacts from Ammonia Combustion Processes

Area of Science:

• * Combustion Science and Engineering
• * Sustainable Energy and Fuels

Background:

• * The global imperative to transition to low-emission, carbon-free fuels due to climate change.
• * Hydrogen's potential is hindered by complex and costly handling, making ammonia a viable alternative for decarbonization.
• * Ammonia offers advantages for large-scale power, decentralized energy, and off-grid industrial applications, positioning it as a key future fuel.

Purpose of the Study:

• * To review recent advancements in ammonia combustion, focusing on factors influencing chemical reaction pathways.
• * To analyze NOₓ emissions and their generation mechanisms in ammonia-based flames.
• * To discuss strategies for mitigating NOₓ production and enhancing ammonia flame stability.

Main Methods:

• * Comprehensive literature review of laboratory and industrial-scale ammonia combustion studies.
• * Analysis of factors such as equivalence ratio, fuel mixture, pressure, and temperature on combustion and emissions.
• * Exploration of advanced techniques like plasma-assisted combustion for emission reduction.

Main Results:

• * NOₓ emission peaks observed at equivalence ratios of 0.8-0.9 for ammonia/hydrogen blends.
• * Richer fuel blends demonstrated effectiveness in reducing NOₓ production by increasing NH₃ radical generation.
• * Plasma-assisted combustion identified as a promising NOₓ mitigation strategy.

Conclusions:

• * Ammonia combustion research is crucial for developing sustainable low-carbon energy solutions.
• * Further investigation into reaction mechanisms, computational models, and fundamental phenomena is essential for practical applications.
• * Optimizing fuel blends and employing advanced combustion techniques are key to reducing emissions and improving efficiency.