Pellet is a fuel lump that can be made of various types of biomass such as bark and tree pruning, sawdust, shavings, waste from construction and loggings.
Once collected, crushed, and dried, these materials are made into powder that is compressed to obtain the final form. During production, 6 to 8 cubic meters of sawdust or wood chips are compressed to high pressure in a cubic meter of wood pellets. The result is a composite 100% natural, high calorific value.
The burning of pellets does not produce smoke, unlike other fuels.
Besides the advantages of efficiency in consumption brought about by the pelleting process of fabrication, prices are also normally stable because they are a renewable source, unlike the case with fossil fuels.
The lignocelluloses wastes used for the manufacture of pellets are an abundant resource in Brazil. If properly exploited, will reduce substantially the energy dependence we currently have on oil, resulting in a huge range of benefits to the economy, and therefore, in their marketing prices.
The production of wood pellets is influenced by different physical properties such as moisture content, particle size distribution, and mass density and operation parameters. The wood pellet has grown rapidly over the last decade, and continues to grow at an impressive rate. Making pellets is about quality, productivity and energy used.
Before producing pellets, the materials are dried off. The moisture content usually cannot exceed 10%.
The compression above 1000 bar allows them to remain stable during transportation and handling all the way to its burning process. As result of drying and pressing, the pellets have moisture content up to 8%, a density of more than 650 kg per cubic meter and a calorific value between 4.9 and 5.4 kWh per kilogram. In general, 2kg of wood pellets replace about one litter of fuel oil.
The high density of wood pellets allows a compact storage and a more economical transportation. They are easily unloaded and moved, using existing systems, such as a screw conveyor or suction equipment. This high density enables further improvement of combustion properties.
The production of wood pellets, with their pressing and drying processes corresponds to less than 4% of the energy content of the final product. For this reason, wood pellets are significantly better than the fossil energy sources, for which 10-12% of its energy is needed for treatment and purification.