Nitrogen Management in Coal Combustion Systems

Coal combustion remains a major source of energy worldwide but also a significant emitter of nitrogen oxides (NOx), which contribute to acid rain, photochemical smog and ozone formation. Effective nitrogen management encompasses strategies at all stages of coal utilisation. Pre-combustion approaches include coal washing, pyrolysis and the incorporation of mineral or alkali additives to alter nitrogen speciation and reduce volatile nitrogen release. Combustion control relies on burner design, staged air injection and flue gas recirculation to moderate peak temperatures and limit thermal NOx formation. Post-combustion treatments such as selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR) employ catalysts or reagent injection to convert NOx into harmless nitrogen and water. Advances in modelling, materials science and process integration are opening new pathways: engineered sorbents capture nitrogen compounds before release, biochar and doped carbon materials facilitate in situ reduction reactions, and coupled carbon–nitrogen management schemes integrate NOx control with carbon capture. Emerging research focuses on tailoring coal feedstocks, optimising metal-ion catalysis and exploiting computational tools to predict reaction mechanisms, all aimed at meeting tightening emission standards and ensuring cleaner power generation.

Research from Nature Portfolio

No recent Nature Portfolio content available.

Nitrogen Management in Coal Combustion Systems publication trend

The graph below shows the total number of articles in nitrogen management in coal combustion systems across all publications each year (not limited to Nature Index journals).

Technical terms

Nitrogen oxides (NOx): Collective term for nitric oxide (NO) and nitrogen dioxide (NO₂) generated during high-temperature combustion.

Char: Solid, carbon-rich residue remaining after thermal decomposition (pyrolysis) of coal or biomass.

Pyrolysis: Thermal breakdown of coal in the absence of oxygen, yielding char, tar and volatile gases.

Pyridinic nitrogen (N-6): Nitrogen atoms incorporated into six-membered aromatic rings, influencing char reactivity and catalytic behaviour.

Pyrrolic nitrogen (N-5): Nitrogen atoms bonded within five-membered heterocyclic structures in carbon matrices, affecting nitrogen release.

Selective catalytic reduction (SCR): Post-combustion process using a catalyst and reductant (often ammonia) to convert NOx into nitrogen and water.

Density functional theory (DFT): Quantum mechanical modelling approach used to predict reaction energetics and mechanisms on material surfaces.

References

1. Effects of calcium on the evolution of nitrogen during pyrolysis of a typical low rank coal. International Journal of Coal Science & Technology (2019).
2. The Occurrence and Distribution of Nitrogen in Coal of Different Ranks and Densities. Minerals (2024).
3. Theoretical Study of the NO Reduction Mechanism on Biochar Surfaces Modified by Li and Na Single Adsorption and OH Co-Adsorption. Molecules (2024).
4. Fuel flexible power stations: Utilisation of ash co-products as additives for NOx emissions control. Fuel (2019).