Pellets

Pellets have been used for over a century for different applications and purposes. Essentially though all pellets are based on the same principles, and are produced for the same advantages. Raw materials for example wood chips, straws and grasses in their loose form have very little value. One of the key reasons for this, is in their raw form they are very hard to deal with, so it is very difficult to design systems around these resources. For the animal feed industry for example they choose pellets as they can create specific feed blends easily and then distribute the feed much cheaper in the compressed form of a pellet. It also makes it much easier to measure out a specific amount each day to feed to the animals, and storage space for the feed is also dramatically reduced. Recently pellets have been used as a replacement to conventional heating fuels. There are several reasons for this which are explained below.

Wood Pellets

Wood pellets are currently the most common and well known form of pellets used for fuel. Most wood pellets currently available on the market are also premium wood pellets. Premium wood pellets are the higher grade of wood pellet fuel. To produce a premium grade fuel pellet most or all of the bark must be removed from the wood. Also only certain species of wood are generally used, these include pine, spruce and oak. The reasons for this is a premium quality wood pellet also has to produce a very low ash content, usually below 1%. Premium wood pellets must also have a very low moisture percentage, below 10% however many manufactures produce pellets with between 5-8% moisture. A lower moisture content means a far more efficient burn, which produces more heat, less ash and smoke. For example wood chip fuel contains around 30% moisture, therefore wood pellet fires produce a far more efficient process.

Pellet Fuel

Although currently wood holds the spotlight as 'the pellet fuel', many other biomass resources can also be processed into fuel pellets, see left for examples.

Pellet Mill

A pellet mill is the piece of equipment which is used to process process wood and other biomass resources into pellets. Through a combination of heat and pressure the pellet mill reforms the material into pellets of various different diameters. The pellet production process however does rely on the right equipment and the right user knowledge. For example the raw material requires certain properties, for example moisture percentage to produce the best quality pellets. Therefore we at PelHeat have developed the Wood Pellet Production Guide to educate people interested in pellets to the principles of production. The guide is broken up into a step-by-step guide including diagrams to illustrate what does and what doesn't work to produce quality pellets.