Wood pellets

A hand sprinkling wood pellets.

Case - Published 4.7.2014

Wood pellets are a Finnish fuel product made from renewable natural resources, which can be used to produce heat by heat production facilities, housing associations and property companies, or holiday homes. Pellet heating is an ecologically sustainable heating technology.

There are a number of different solutions available. The pellet heating system is chosen on the basis of the user’s needs. Pellet-burning fireplaces are a good additional option to heat single-dwelling houses. Automatic pellet burning systems are available for small houses as well as larger housing units, such as terraced houses. Pellet heating containers can be used at larger heating plants.

Wood pellet burning process releases the same amount of carbon dioxide as the amount trapped from air by the growing tree. The same amount of carbon dioxide would be released during the rotting process if the tree was left in the forest. As a consistent biofuel, the pellet offers a heating technology that can help to abate climate change.

As the pellet is clean energy compressed into a small size, its transportation is easy and efficient. As a heating material, it is convenient and harmless to handle. The heat value of one tonne of pellets is very high at approximately 4.8 MWh, which corresponds to roughly four stacked cubic metres of firewood or 450 litres of heating oil.

The HOTTI pellets provided as a sample*) are manufactured from dry spruce and pine and cutter shavings which are by-products of the wood-processing industry. Clean wood pellets do not contain bark or round wood chips.

During the production process, the raw material is processed in a hammer mill into small wood particles and compressed into pellets. During the compression process, the temperature of the raw material rises very high, and the tree’s own binding agent, lignins, bind the wood mass into pellets. After compression, the pellets are cooled down, at which point they reach their final state of hardness. The cool pellets are then screened. Fine material is redirected to the hammer mill, and only the pellets are stored in silos.

The quality of the pellets is assured through continuous testing. The pellets are tested for mechanical durability, moisture and density.

The pellets provided as a sample*) originate from the Versowood pellet factory in Vierumäki, which is located along the Heinola-Lahti motorway. The factory produces enough pellet in an hour to heat two medium-sized single-dwelling houses for a whole year.

Text and photos are from the info cards in the presentation briefcase on the Finnish forest sector. The idea of a briefcase with various kinds of samples to present this diverse sector came from the young people themselves. The briefcase has been handed out at visits to upper secondary schools.

More information on the briefcase and visits: vilma.issakainen(@)smy.fi and anne.kettunen(@)forestindustries.fi.

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