Converting a coal mill to biomass is not a grinding problem but an air problem. EnFloTech reconfigures the mill to break pellets back to their pre-pelletised particle size distribution, controlling air circulation and velocity to eliminate the eddies that suspend flakes and block mills. The result: full throughput at 100% MCR, stable firing, equal distribution to PF pipes and no pellet rejection. Proven on the Babcock 10E10 mills at Drax and on Lynemouth's MB mills.

Repurposing the mill, not replacing it

A coal mill converted to biomass is being asked to do a fundamentally different job. Coal must be ground finer and finer; a biomass pellet does not. The pellet is already a controlled composition of wood flakes, manufactured to a known specification, and its pre-pelletised particle size distribution (PSD) can be regulated at source. Where that regulated PSD already meets the minimum boiler specification, the mill's task reduces to breaking the pellet back down into the flakes it was made from and nothing more.

That insight is the foundation of EnFloTech's conversion philosophy, and it is what allows existing mills to be repurposed rather than replaced.

Why conversions fail, and what fixes them

The difficulty in biomass milling is rarely mechanical. Wood flakes are light, irregular and easily held in suspension, so the behaviour of the air inside the mill decides whether a conversion succeeds. Uncontrolled circulation produces eddies, eddies produce suspended particle clouds, and the consequences follow quickly: flakes held in suspension, material settling in pulverised fuel pipes, blockages, uneven distribution to the burners and pellets rejected before they are ever broken down.

EnFloTech's design eliminates particle recirculation by controlling the air circulation behaviour within the mill and its velocity, so that no suspended particle clouds can form. The mill is conditioned to convey flakes cleanly through to the boiler rather than to hold them in circulation.

What a converted mill achieves

• Desired throughput to run the boiler at 100% MCR
• Stable boiler firing
• Elimination of mill blockages
• Prevention of material settling in PF pipes
• Equal distribution to PF pipes
• Elimination of biomass flake suspension
• Elimination of biomass pellet rejection

Proven at scale

EnFloTech converted the Babcock 10E10 mills at Drax Power Station, at the time the largest biomass power station in the world. The company has since completed conversions at Lynemouth Power Station in Northumberland, where three units of 140 MW each run on biomass through MB 195 series vertical spindle mills. Both stations contribute directly to the UK's CO2 reduction commitments.

Why it matters for the region

For operators facing decarbonisation targets against a young and heavily capitalised coal fleet, fuel switching offers a route that does not require writing off the asset. Conversion keeps the boiler, the mills and the generating capacity in service while changing what they burn — a materially faster and cheaper path to lower CO2 than replacement, and one already demonstrated at utility scale.