Wood pellets are a natural and environmentally friendly type of heating. They do not cause the environmental pollution in the way of CO2 emissions, and residues from wood-processing are used as a raw-material in their production. By choosing this type of heating, you will take care not only of the warmth at your home but also of the surrounding environment.
Wood pellets are produced by pressing wood chips. As a result, cylinder-shape pellets with 4-10mm diameter and 12-30mm length are obtained. Under high pressure and temperature wood develops lignin which acts as a natural binding agent and keeps the pellet together.
Unlike such types of fuel as coal and diesel fuel, wood pellets are a CO2-neutral type of heating, as during its growth a tree binds the carbon dioxide generated from pellet combustion process. That means that by using wood pellets the nature is being conserved, not contributing to the so called 'greenhouse effect'.
Prior to pellet pressing the required raw material is dried and cut into small bits. During the pellet production process the dried chips are pressed - between 7 and 10 m³ of chips are used for producing 1 m³ of pellets.
Wood pellets must be dry (with humidity up to 10%), free of any chemical admixtures (glue, varnish, etc.) or dust, and they must be hard and disintegration-resistant.
When appropriate storage conditions are ensured, the pellets packaged in polyethylene bags can be stored for a very long time. Pellets can be stored in dry, even not heated facilities. Pellets must be guarded against moisture in the way of condensate or water. Unpackaged pellets can be stored at a warehouse for several months, as the air humidity has a slow effect on them.
Wood Pellet Advantages
- Environmentally friendly, CO2-neutral fuel.
- Ecologically pure and non-allergic product.
- When wood pellets are incinerated in specially designated boilers, very high thermal efficiency can be achieved, efficiently using up to 92% of the generated power.
- The heating system with pellets can be automated, as both the pellet container filling and ash cleaning can be carried out once a week (for some types of boilers even as rarely as once a month).
- Guaranteed pellet availability, as the raw materials for the pellet production are by-products of the wood processing industry which is one of the biggest industry sectors in Latvia.
- Storing pellets requires less space than for storing firewood.
- A small ash amount is generated in the pellet incineration process - up to 5 kg of ash from a tonne of pellets.
- Local raw materials and man-power are used for the pellet production, thus benefiting the Latvian economy.
Options for Use of Wood Pellets
- Heating systems of enterprises and municipal economies.
- Private house and apartment boilers and fireplaces.
- Big power-plants and cogeneration plants for heat and power generation.
- Containing spills in case of emergency.
- In animal farming as waste absorbers.
Wood Pellets for Household Heating
Usually wood pellets with the ash content up to 0.5%, known as the top quality pellets, extra quality pellets, 'light' pellets or DIN+ grade pellets, are used for household heating. DIN+ is a German standard for high quality pellets, also applied elsewhere in Europe.
Mainly top quality pellets packaged in 15-30 kg bags are available for purchase at stores or home delivery in Latvia. The bags are emptied into the boiler container, and then transported by a feeding mechanism to the furnace.
The pellets can also be delivered in bulk, e.g. for the entire heating season at once. That ensures a cheaper pellet purchase price, as the pellets are sold unpackaged and in bulk.
In such cases the pellets are transported on specially equipped trucks which feeding devices use pressurised air for filling the pellets into storage containers, from where they are fed to the boiler as required.
Wood Pellet Use at Power-plants and Cogeneration Plants
Usually pellets with ash content between 0.5 and 1.5% are used at power-plants and cogeneration plants. These pellets are known as industrial quality pellets or pellets complying to DIN quality. DIN is a German standard for industrial pellets, also applied elsewhere in Europe.
Power-plants and cogeneration plants generate heat and power from the pellet combustion process. Such pellets are mainly offered unpackaged or in BIG BAG packaging. For export purposes the pellets are mainly transported on vessels, which in terms of costs is a cheaper way than using any land transport.
Many experts of the field forecast a stable growth of the wood pellet market, as many countries are announcing national support programmes for the use of an environmentally friendly fuel, and the society is becoming more and more educated in the environmental protection issues.