Fuel pellets market is
increasing steadily over the last
decades mainly due to the rising cost of fossil fuels, as well as of the
environmental policy which promotes the renewable energy sources such as
biomass.
Pellet is a fuel that comes from the combination of wood and biomass once the moisture has previously been removed from them. Wood and biomass are pressed together into special presses without the use of additional adhesives and take the shape of small, high density and low-moisture rollers. These cylinders are small in size, allowing them to be moved by mechanical means (screws, conveyors, etc.), and they are also friendly for easy and practical packaging. The soldering of pellet components and their consistency take place due to lignin, which is a natural adhesive that is extracted during the pressing of wood at the high pressures of the pellet-making machines. The pellet cylinders are 6-8 mm in diameter, about 40 mm in length and their color depends on the raw material used. There are 7 different stages during the production process of pellets:
• Storage of raw materials
• Cleaning of raw materials from impurities
• Drying of wood and biomass
• Grinding and cutting of wood and biomass
• Pelletizing
• Cooling and sieving of pellets
• Storage of pellets
It is very easy to make pellets by ourselves with agricultural residues such as prunings
from various fruit trees, vines, olive trees and other crops that we may have
at our disposal. Pellets can also be made from plants whose trunk or branches
are made of woody tissue. With the above mentioned materials we produce pellets
which are called “agri-pellets” and they can be
burned in special burners such as
biomass burners and wood pellet burners. They can be burned in simple wood boilers too and even in stoves,
but because of the relatively quite big quantity of ashes produced by their burning, the machine that will burn
them will need frequent cleaning.