19 Januar 2009

Mobile Straw pelletising unit for farm-scale production

Prototype produces 200 kg per hour

A mobile pelletising unit being developed by a Staffordshire company could make smaller-scale pellet production feasible for farmers. That means they could produce fuel for their own use e.g. from rape or cereal straw by burning it in a biomass boiler and also sell the pellets locally. The british magazine “Farmers weekly” reports about the development of a mobile pelletiser by the British company Pelheat.

Existing pelletisers tend to be large, static, semi-industrial units costing from £50,000 upwards, Christopher Scott from maker Pelheat 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.

The unit is still in prototype form. As Christopher Scott told the News Portal www.nachwachsende-rohstoffe.info, the company hopes it will be available within the next four months. The units will be powered by an onboard 20hp Perkins diesel engine, which can also run on biodiesel under warranty. Estimated throughput for this unit will be between 100-300kg/h for wood pellets and high density materials, and between 200-400kg/h for grass/straw pellets and low density materials. The unit will produce 6mm or 8mm pellets. The cost is expected to be about £20,000 to £25.000 (approx. €22,100 to €27,600).

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. The unit will require the raw material to have a moisture content between 10-20%, generally the best quality pellets are produced between 13-15%. Raw material input size for the hammer mill should have a diameter no larger than 1 inch.

Larger units, involving a 50hp engine and about 600kg/hour throughput are also in the pipeline.

Source: Farmers weekly, 2008-08-01 and Christopher Scott (Pelheat), pers. comm., 2008-01-19.


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