Pellets is fuel granules, biomassa, arboreal granules, wood pellets, holz-pellets, holzpellets, bio granules are an alternative industrial fuel.

A wooden granule is ecologically harmless, clean fuel material with high heating value that is used in automated racing devices.

Fuel material standard.

There is standard for this kind of fuel in Germany: DIN 51731 “Requirements to the materials produced as a result of natural wood pressing”. According to these standard requirements granules are to be 6-8 mm across transverse diameter and approximately 20mm at length. The use of the accessory materials such as glue and plastic is not allowed in the production and pressing processes. Resin content according to the standard amounts to less then 1,5%. Ashes, generated in the combustion process, can be used as a fertilizer or can be liquidated as debris. Granules filling compactness makes up to 650 kg/ m³. It’s rather high index for wooden materials and as a result of high energy compactness they need much less space for storing then wooden logs o wood chips. In the process of burning the rate of escaping harmful substances is at record low index, moreover energy consumption required for the production of wooden granules amounts to approximately 3% of energy content and that is much lower then the percent of energy consumption required for the production of natural gas or fuel oil. Wooden granules can be used for heating in combination with other renewable sources of energy as well as without them.

Technology of the production.

Wooden granules ensue in the pressing process under high pressure of wood chips and wood dust and have heating value of 4,9 K.W.H./kg and that is approximately in the line with half of the litre of fuel oil.

The production of granules is not of course the discovery of the XX century. This technology was already used in the XIX century for the purpose of transformation of organic and inorganic materials into compact form and also for improvement of their treatment. Although only recently wood granulation with the purpose of further use of wooden granules in heating devices became widely popular.

A wooden granule is a combustible material, the production of which is regulated in accordance with standard. This makes their use easier and allows to automatize heating. Existing standards simplify their transportation and use. Thus granules can be delivered packed or as bulk cargo and transported in the same way as fuel oil by means of tank truck and are loaded in storehouse.

Unpacked materials are delivered in tank trucks that are usually used for granular material transportation and intended mainly for the use in central heating devices. Its price is formed from the price of the fuel, transport charges, general costs for loading of the fireplace and receipts tax. Packed (in so-called Big-Bags) wooden granules are transported in placed on bolsters bags with capacity of 15 or 25 kg. Such way of transportation of wooden granules is especially convenient for fireplace loading for heating of cottages.

How to store granulated fuel?

Wooden granules are kept in special depots, for instance in cisterns or in bunkers for granular materials, as well as in bags or in underground shelters. In case of storing unpacked granules it is necessary to pay attention to the protection of the shelter against humidity and dust emissions.

There is cover on the coupling that protects against atmospheric precipitates. The whole filling system should be short as much as possible. During the designing process it is recommended to avoid bends at angle of 90. in case if the distance between aperture for suction of granules and opposite wall is more then four meters percussion-catoptric wall-mat made of rubber should be placed on this wall in order to avoid granule crumbling. Theoretically it is necessary to adjust the construction with suppliers of wooden granules.

For organization of depository in buildings that were heated earlier with the help of fuel oil one existing cistern is usually enough. If the building of new house that will be heated with the help then of wooden granules is indented depending on the use of heat power the necessary capacity of depository should be approximately 0,9 m³/ kilowatt. Floors in the depository should be situated at angle of approximately 45 degrees to screw for unloading of the depository, and then it will be easier to empty the depository. As an alternative storehouse for granular material, underground cistern or specially-made steel cisterns can be used. The use of special depository is advised in fire regulations only in case of big fuel volume (more then 15 tons).