Wood Pellets Production

Wood Pellet Maker

 Nowadays, an increasing number of people are utilizing wood pellet maker to creat wood pellets as the replacement of fossil fuels.


What are wood pellets? 

Pellets are a form of biomass material (usually wood), dried and processed into easily combustible pellet form. They are clean to handle and their ‘free flowing’ characteristics make them ideal for automatic heating systems.


 How are they made?

Biomass material is milled onto fine sawdust; this is often derived from recycled pallets. It is then fed into a pelletising machine where it is compressed under immense pressure and extruded through a die. During this process the lignin, naturally contained in the biomass, melts and acts as a 'binder' stitching together the fibres to form an extruded pellet section and helping to keep the shape of the pellets as they dry. The lignin also gives rise to the 'glaze' found on the exterior of the pellets. The pellets are extruded at around 90oC, the lignin then cools and the pellets harden and set. No other additives are used. After cooling the pellets are either bagged up for domestic use or loaded into container lorries for bulk distribution. Pellets supplied by the bag are currently up to twice the cost of pellets bought in bulk (delivered by the tonne).


Pellets can be made from various biomass materials. One of the most common is excess wood from the joinery industry in the form of sawdust, or recycled pallets. Pellets are also made from specially grown crops such as willow coppice or even from straw.

Pellets vs. Wood Chips?

Wood chips (at 25% moisture content) are cheaper than pellets per unit of energy delivered. However, they are not always suitable for domestic or intensive heating uses since they require considerably more storage space and their energy content is less predictable. The volumetric bulk density (weight per unit volume) of wood pellets is significantly higher than that of wood chips; this figure depends on the moisture content of the wood chips but as a guide: 
• wood pellets: 650kg/m3 (based on wood pellets <10% moisture
• wood chips: 200kg/m3 (based on wood chips 25% moisture
Wood chips require at least three times the storage space as wood pellets for the same energy content.


 As what is mentioned above, we can clearly see the advanatges of wood pellets. And that's why people are choosing wood pellet makers.