Co-Firing Wood Pellets in Coal Plants: Requirements
Practical requirements for co-firing wood pellets with coal: milling, handling, fuel spec limits, storage safety, and typical co-firing ratios.
Co-firing is the fastest route to lowering the carbon intensity of an existing coal unit, because it reuses the boiler, turbine, and grid connection. The fuel, however, behaves nothing like coal.
Typical co-firing ratios
- Up to 5 % thermal: direct co-milling, minimal modification
- 5–20 %: separate milling and dedicated burner feed
- Above 20 % to full conversion: new mills, silos and burners required
Milling behaviour
Pellets disintegrate in a coal mill into fibrous particles rather than brittle dust. Mill throughput drops and classifier settings need retuning. Many plants install hammer mills specifically for biomass instead.
Fuel specification limits
Chlorine and alkali metals are the operational constraint. Potassium and chlorine from bark-rich pellets combine to form deposits on superheater tubes and accelerate high-temperature corrosion. Insist on Cl ≤ 0.03 % and low K for high co-firing ratios.
Storage and safety
Pellets self-heat and off-gas carbon monoxide in sealed silos. Coal plant storage must be re-rated: CO monitoring, inert gas capability, temperature probes, and strict entry procedures.
Sustainability compliance
Most regulated markets only credit co-fired biomass if it carries SBP or equivalent certification with lifecycle GHG accounting. Uncertified tonnes may burn fine and still earn nothing.
We supply certified industrial 8 mm to co-firing operators with full ash chemistry and trace element reporting per shipment.
Pellet Industries ships ENplus A1 and industrial biomass pellets worldwide in 15 kg bags, big-bags, and bulk vessel loads.
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