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Wood pellets production

The wood pellets are an important bio-energy and their use is increasing every year, because of the optimal relation of price/calorie. The heating power of wood pellets are from 4,8 to 5.3 kWh/kg.
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How to choose the Plant Capacity and machinery  

The wood pellets are an important bio-energy and their use is increasing every year, because of the optimal relation of price/calorie. The heating power of wood pellets varies from 4,8 to 5.3 kWh/kg.

The diameter of the pellet can be chosen and normally is between 6 and 10 mm., the length is variable from 30 to 50 mm.
The humidity of the wood pellets is normally between 7 and 10% and the specific weight is around 650 kg/m3.

 

Raw materials

The production of wood pellets can be made starting from dry sawdust as well as from damp sawdust, chopped wood, wood – shaving, wood chips. The wood types are different, the most used are the coniferous, but other types such as deciduous, eucalyptus, chestnut are useful too.

The pellets cannot be produced with brushwood, straw, bark, etc. because this would jeopardize the quality for domestic combustion due to the high level of silica and ash. Tests are being performed to use these products for the industrial production of electrical energy.

 

saw dust for wood pellet production


Wood Pellets production starting from dry sawdust 

The installation of a wood pellet production line is justified when there is the availability of dry low-cost sawdust in a quantity no lower than 3,000 tons/year (60 m3/day x 250 day/year). The humidity of the sawdust has to be between 9 – 12 %.

In this case, chopping and drying are not necessary, and the production line consists only in:

  • sawdust pre-pelleting silo
  • pelleting press
  • pellets cooler
  • finished product silo

The production needs about 150-170 KW/ton.

When the sawdust pellet plant is successfully completed and commissioned, the main cost for sawdust pellet production will be raw materials, the running of machines, the wear and tear of ring dies, the labors etc.


wood chips for pellet production

Wood Pellets production starting from wet wood chips

If the sawdust is damp or the chipped wood needs to be grind, the minimum production of pellets necessary to justify the investment of a complete system must be 5-7000 tons/year, equal to approximately 10,000 tons/year of damp sawdust and chop’s wood.

In this case chopping and drying are necessary, and the production process is more flexible, but more expansive and includes the following steps:

  • the grinding: to chop the pieces of wood
  • the drying: to reduce the humidity to 9-12%
  • the beating of the dried chips: to grind evenly the wood after the chopping and drying processes
  • the pelleting: to form the pellets
  • the cooling of pellets: to cool before the other steps
  • the sieving storage: to remove dust before the storage of finished product
  • the storing: before packaging or delivery of the loose product 

The production needs about 200-220 installed KW/ton depending on the different capacity and the technical installation to be made. 

Since there are different variables to consider, you can Contact Us asking for an offer and explain your specific needs. Our engineers will help you choose the best for your needs.