Pellet Mill Common Terms
Agricultural residues
Biomass residues originating from production, harvesting, and processing in farm areas.
Agrofuels
Biofuels obtained as a product of energy crops and/or agricultural residues.
Biodegradable
Capable of undergoing anaerobic or aerobic decomposition. Biodegradable is understood as material capable of undergoing anaerobic or aerobic decomposition under conditions naturally occurring in the biosphere.
Bioenergy
Energy derived from biofuels.
Biogenic
Produced by living organisms in natural processes but not fossilised or derived from fossil resources. The term biogenic is used to denote CO2 -neutral material when degraded under aerobic conditions.
Biomass
Material of biological origin excluding material embedded in geological formations and transformed to fossil. Refers to the biodegradable fraction of products, waste and residues from agriculture (including vegetal and animal substances) forestry and related industries, as well as the biodegradable fraction of industrial and municipal waste.
Biofuel
(= biomass fuel) Fuel produced directly or indirectly from biomass. The fuel may have undergone mechanical, chemical or biological processing or conversion, or it may have had a previous use. Biofuel refers to solid, gaseous and liquid biomass-derived fuels.
Black liquor
Alkaline spent liquor obtained from digesters in the production of sulphate or soda pulp during the process of paper production. The energy content mainly originates from the content of lignin removed from the wood in the pulping process.
Bundled biofuel, bundle
Solid biofuel which has been bound together and where the material has a lengthwise orientation. Bundles of energy forest trees and logging residues, small trees, or branches and tops.
Cutter chips
Wood chips made as a by-product of the wood processing industry, with or without bark.
Demolition wood
Used wood arising from demolition of buildings or civil engineering installations. Demolition wood is classifed as solid recovered fuel (SRF).
Energy forest trees
Woody biomass grown specifically for its fuel value in medium to long rotation forestry.
Energy grass; fuel grass
Herbaceous energy crop, e.g. reed canary grass.
Energy plantation trees
Woody biomass grown as short rotation trees specifically for its fuel value.
Firewood
Cut and split oven-ready fuelwood used in household wood burning appliances like stoves, fireplaces and central heating systems. Firewood usually has a uniform length, typically in the range of 150 mm to 500 mm.
Forest fuel
Wood fuel produced from raw material that has not previously been in another use. Forest fuel is taken from the forest and processed directly for energy use. Forest fuels can be derived from logging and thinnings.
Forest residues
Woody residues consisting of branches, tree tops, brushwood and small trees not harvested or removed from logging sites in commercial wood stands, as well as material resulting from forest management operations.
Fuel peat
Peat product intended for energy production. Fuel peat is a local, indigenous, solid fuel which is used as milled peat or sod peat as well as peat briquettes and pellets.
Fuel wood, energy wood
Wood fuel where the original composition of wood is preserved.
Green chips
Wood chips made of fresh logging and thinning residues, including branches and tops.
Grinding dust
Dust-like wood residue formed from grinding timber and wood boards.
Fuel wood; energy wood
Wood fuel where the original composition of wood is preserved.
Herbaceous biomass
Biomass from plants with a non-woody stem which die back at the end of the growing season.
Hog fuel
Fuel wood in the form of pieces of varying size and shape, produced by crushing with blunt tools such as rollers, hammers, or flails.
Log wood
Cut fuel wood in which most of the material has a length of 500 mm or more.
Logging residues
Woody biomass residues created during harvest of merchantable timber. Logging residues include tree tops with branches, and they can be salvaged fresh or after seasoning.
Milled fuel peat
Fuel peat produced by milling peat from the surface of the peatland and by drying it. Drying is normally done at the peat site by solar energy. Milled fuel peat is non-homogeneous in particle size and contains mainly pulverous peat as well as peat particles of various sizes. In addition to peat material, milled peat may also contain limited amounts of non-decomposed or poorly decomposed coarse plant parts (bog wood, shrubs, sheathed hare’s-tail cotton grass, etc.) as well as limited amounts of impurities.
Particle board residues
Residues from particle board, which is a panel product produced by densifying small particles of wood or similar lignocellulosic materials while simultaneously bonding with an adhesive.
Peat
Peat is decomposed material which has accumulated in waterlogged conditions. A substantial proportion consists of dead organic, plant-based matter. It is a slowly renewable natural resource for which there are many uses, particularly in energy and horticulture. Its carbon content and calorific value, particularly those of highly decomposed peat, make peat suitable for use in energy. Also the cellular structure, low pH and low nutrient status, particularly those of slightly decomposed sphagnum peat, make peat suitable for use in horticultural growing media.
Plywood residue
Woody biomass residues formed in plywood industry.
Pellets
Fuel in the form of short cylindrical or spherical units. Pellets are usually 8–12 mm in diameter and 10–30 mm in length, with moisture content of less than 10%. Pellets are usually produced from woody, herbaceous and fruit biomass or peat.
Pyrolysis oil
Liquid biofuel which is produced in fast pyrolysis by heating wood (moisture content less than 10%) up to 500 – 600 oC for a very short time. The organic particles are transformed into gas, which is then converted to a liquid (oil). In general, the bio-oil yield is about 70 w-%.
Recovered construction wood
Used wood arising from construction of buildings or from civil engineering works.
RDF (Refuse Derived Fuel)
Fuel produced from unsorted municipal waste with a mechanical handling process.
Recycled wood fuels
Recycled wood fuels include post-society wood fuels, such as demolition wood, wood casings and other waste wood.
Refined fuel
Biofuel that has been treated mechanically or chemically to homogenise its properties, e.g. pellets, briquettes and pyrolysis oil.
Renewable energy sources (RES)
Refers to renewable non-fossil sources (wind, solar, geothermal, wave, tidal, hydropower, biomass, landfill gas, sewage treatment plant gas and biogas). In Finland peat is classified as a slowly renewable biomass fuel.
Sawdust
Fine particles created when sawing wood. Most of the material has a typical particle length of 1 to 5 mm.
Sod peat
Fuel peat produced by extracting peat from the peatland, by processing it mechanically to sods (e.g. cylindrical, wave-like). The sods are dried out by solar energy, mainly at the peat site. Peat sods are fairly homogeneous in diameter or shape, while the length of the sods may vary. Sod peat also contains variable amounts of fines formed in the production and treatment stages, as well as coarse particles and limited amounts of impurities.
Solid recovered fuel (SRF), recovered fuel (REF)
Solid fuel which is prepared from non-hazardous waste to be utilised for energy recovery in incineration or co¬incineration plants, and which meets the classification and specification requirements laid down in CEN/TS 15359. “Prepared” here means processed, homogenised and up-graded to a quality that can be traded amongst producers and users.
Stump
Part of the tree stem below the felling cut.
Wood chips
Chipped woody biomass in the form of pieces with a de?ned particle size produced by mechanical treatment with sharp tools, such as knives. Wood chips have a subrectangular shape with a typical length of 5 to 50 mm and a low thickness compared to other dimensions.
Wood fuels, wood based fuels, wood-derived biofuels
All types of biofuels originating directly or indirectly from woody biomass.
Wood processing industry residues
Woody biomass residues originating from the wood processing and the pulp and paper industry, e.g. bark, cork residues, cross-cut ends, edgings, fibre board residues, grinding dust, particle board residues, plywood residues, saw dust, slabs, and wood shavings.
Wood shavings; cutter shavings
Shavings from woody biomass created when planning wood.
Woody biomass
Biomass from trees, bushes and shrubs. Forest wood, wood processing industry residues, fibre board residues, particle board residues, plywood residues, and used wood are woody biomass.
Used wood
Wood substances or objects which have performed their intended purpose.
NOTE: The terminology is based on European technical specification CEN/TS 14588 for solid biofuels, RES-E directive 2001/77/EC, Nordtest NT ENV 009 - Fuel Peat guidelines, European technical specification CEN/TS 15357 for recovered fuels and “Wise use of mires and peatlands”. The terms for solid biofuels are unified in the European standard CEN/TS 14588. FAO, ASTM, and national standardisation institutes have also published terminology for biomass fuels.
