A mobile pelletising unit being developed by a Staffordshire company could finally make smaller-scale pellet production feasible for farmers. That means they could produce fuel for their own use from rape or cereal straw by burning it in a biomass boiler and also sell the pellets locally.

So far the unit is still in prototype form, but Christopher Scott from maker Pelheat says that the first production machines should be on sale before the end of the year.

Existing pelletisers tend to be large, static, semi-industrial units costing from £50,000 upwards, he says. The Pelheat version, on the other hand, is mounted on a small trailer and can be towed behind a car or pick-up.

The process involved is fairly simple, too, with material passing through a hammer mill, then into a hopper from where it is augered into a pellet mill that makes either 6mm or 8mm diameter pellets. Water or oils can be added at this stage to make the pellets bind.

 pelheat pelletiser
Pelheat’s mobile pelletiser could make small-scale pellet production feasible on-farm.

The smallest model will be powered by a 24hp Perkins engine and has a typical throughput of 200kg of pellets an hour. Cost is expected to be about £20,000. Larger units, involving a 50hp engine and 600kg/hour throughput are also in the pipeline. Getting the straw into the machine simply involves unrolling a round bale and feeding it in by hand, says Mr Scott. Almost anything with a moisture content below 15% can be pelletised, including wheat and barley straw, oilseed rape cake (what’s left after the oil has been extracted), dry woodchips, sawdust, miscanthus, canary or switch grass.

There are a number of biomass boilers on the market that could burn the pellets and the unit wouldn’t take long to produce the 10t or so that would typically be needed to heat a farmhouse for six hours a day and four months of the year with a 50kW burner. But the real benefit will come from selling the fuel locally to other biomass boiler users.