Combustion Dynamics of Co-Firing Biomass and Coal

The co-firing of biomass with coal has emerged as a pivotal strategy for reducing carbon intensity in thermal power generation while maintaining fuel flexibility and operational stability. In these systems, biomass—often supplied in pulverised form or as torrefied pellets—undergoes drying, pyrolysis and char oxidation in regimes that overlap with coal devolatilisation and combustion. The interplay between the two fuels influences flame temperature profiles, residence times and heat transfer rates within the furnace. Biomass typically ignites more rapidly than coal, promoting faster volatile release and enhancing local turbulence, which can improve mixing but also alter slagging behaviour and flame anchoring. Conversely, coal’s higher fixed carbon content sustains burn-out and provides thermal inertia. Optimising air staging, burner geometry and particle size distribution is essential to balance flame stability against emissions of nitrogen oxides and unburned carbon. Advances in optical diagnostics, pilot-scale trials and numerical modelling have deepened our understanding of particle motion, gas-phase chemistry and heterogeneous reactions, thereby guiding retrofit strategies for existing coal facilities and informing the design of next-generation hybrid combustion systems.

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Combustion Dynamics of Co-Firing Biomass and Coal publication trend

The graph below shows the total number of articles in combustion dynamics of co-firing biomass and coal across all publications each year (not limited to Nature Index journals).

Technical terms

Co-firing: Simultaneous combustion of two distinct fuels (e.g. coal and biomass) in a single furnace to leverage complementary properties and reduce net CO₂ emissions.

Devolatilization: Thermal decomposition stage of biomass or coal particles, in which volatile compounds are released prior to char formation.

Char oxidation: Heterogeneous reaction between solid residual carbon (char) and oxygen, producing heat and carbon dioxide during later stages of combustion.

Computational fluid dynamics (CFD): Numerical technique for solving the governing equations of fluid flow, heat and mass transfer and chemical reaction in combustion systems.

Nitrogen oxides (NOx): Collective term for nitric oxide and nitrogen dioxide species formed during high-temperature combustion via fuel-bound and thermal pathways.

References

1. NO formation during co-combustion of coal with two thermally treated biomasses. Fuel Processing Technology (2022).
2. CFD Analysis of Co-firing of Coke and Biomass in a Parallel Flow Regenerative Lime Kiln. Waste and Biomass Valorization (2022).