Raw material

Woodworking is connected with a huge loss of wood. At the logging stage the amount of wasts – stubs, boughs, needles – can reach several dozens per cent of the primary volume.

A typical sawmill turns about 60% of wood into plank, the rest is:

• Sawdust – 12%
• Hungry wood – 6%
• Slab and haggs – 22%

Raw material for pellet production – wood in any form:

• Timber processing wastes
• Roundwood
• Shavings
• Sawdust
• Slab
• Rind

Factors that influence the quality of pellets and production process:

• Content of lignin in wood. Acts as “glue”. Ties small parts of wood together in pellets in process of pressing. The higher lignin content the better is the quality.
• Fractions not bigger than 50 mm and no extra admixtures – stones, metals, sand etc.
• Wood hardness. Wood hardness influences directly the load of units while cutting, pelleting, splitting up, energy consumption, excessive wear of machinery and units.
• The best raw material for fuel pellets production are conifers (pine, fir tree) due to high lignin content and softness of wood
• Birch, larch are hardwood. They are harder and raise excessive wear of units and energy consumption.
• Asp. Practically inapplicable for pelleting. Lignin content is 30% lower than with conifers. The pelleting process is harder and the product is less firm.
• Humidity is not of primary importance – it influences only the duration of drying in the drum dryer.