09/03/2020
DID YOU KNOW?
Pellets are a solid biomass fuel, mainly produced from wood residues but also from agricultural by-products such as straw. They have a cylindrical form with a diameter of 6 – 12 mm. Specific advantages of pellets as compared to un- processed biomass include: standardized properties, high energy content, high density and therefore reduced costs for transport, storage and handling. Pellets are used for residential heating in pellet stoves and pellet boilers, for the gene- ration of heat, steam and electricity in the service industry, manufacturing and power generation.
Bioenergy is the most important renewable energy. When compared to other types of bioenergy, the pellet sector is one of the fastest growing.
Pelletizing technology was invented in the USA in the 1930’s for the production of feed pellets. Bark was pelleted in the United States in the 1950‘s as a way to reduce waste volumes in the sawmill industry. Production of wood pellets for the heating market took off in USA in the 1970s by the time of the first oil crisis followed by Swedish start-ups ten years later.
Sawmills in northern Sweden introduced pellets into the market around 30 to 40 years ago in order to reduce the cost of transport from Northern Sweden to the main consumption regions in the South. Since then, the use of pellets grew continuously for residential heating, power generation, and for heat generation in the manufacturing and energy sectors.
PELLETS – A HIGH QUALITY FUEL FROM BIOMASS
Pellet is a term used for a small particle of cylindrical form produced by compressing an original material. The term is used in a variety of contexts. In the context of energy, we distinguish between wood pellets and agro pellets based on the feed- stock used. At present, pellets are mainly produced from wood residues, though the volume of pellets produced from agricultural by-products such as straw, husks of sunflower seeds and stalks and leaves of corn etc. is increasing.
A key advantages of pellets compared to unprocessed biomass is the high density and high energy content per unit volume . This leads to significantly reduced costs for transport, storage, handling and use.
Another advantage is that they can be produced with standardized properties. This enhances their usability because boilers, stoves or pellet burners can be designed and constructed taking into ac- count the standard fuel properties.
As a rule of thumb it can be said: 3m³ pellets ~ 2 ton pellets ~ 1 000 l heating oil. Standardized quality is also a pre- condition for trading. ISO standards for pellets have recently been adopted that specify different quality classes for industrial use and for use in devices for residential heating (ISO 17225-2). In addition, a quality certification scheme has been in- troduced by the European Pellet Council,ENplus,that guarantees consistent quality of pellets for residential heating purposes by introducing standardized quality management procedures for production and trade. This so-called ENplus certification is now widely used both in Europe and North America.
