biomass pellets are generally produced by a pellet mill out of wood sawdust waste such as sawdust and shavings. The raw material is dried, mechanically fractioned to size and thereafter extruded under intense pressure into pellets. In the pelleting process the raw material is densified approximately 3.7 times. The product produced in Western Canada has a bulk density of approximately 705 kg/m3 and a bulk stowage factor of approximately 52-56 ft3/metric tonne.
Wood pellets are primarily used as a fuel and have a calorific (heat) value of around 5 MWh/metric tonne (18 GJ/metric tonne) which is approximately half that of fuel oil. In North America the wood pellets are used in wood pellet stoves and fire places. In Europe, particularly Scandinavia, the bulk of the pellets produced by wood pellet machine are used as fuel in central heating stations supplying heat for entire communities or even entire cities.sometimes, the family would like to produce wood pellets by pellet mill for home use
Wood sawdust pellets can absorb moisture from the air if stored in a damp environment, and this can lead to them becoming crumbly and breaking down to sawdust. The mechanical durability of wood pellets is important, especially if they are to be subjected to more than a few handling steps. This can particularly be the case with pellets imported from overseas which may have been subject to many handling processes during loading and unloading.
Pellets that break up into sawdust during handling or storage can cause difficulties in fuel feeds and also the much lower effective fuel energy density of sawdust may require the fuel feed to be recalibrated, or cause the combustion system to trip out.
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