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How pellets are formed

For the most part, the densification of the pellet itself is only a part of an overall system
necessary to achieve the finished product. Generally there is a requirement for grinding,
screening, storage bins, special feeding devices and sometimes even drying equipment.
Many of the wood waste materials have unique properties, which necessitate special
equipment: and usually result in lower equipment capacities than "normal" densified
materials. Because they are often waste materials, the wood wastes frequently contain
tramp materials such as metal, stones, glass, etc. Additional processing steps must be
included to remove this tramp material prior to pelleting or densification

The actual pelleting process occurs aider the wood waste that has been through all the
preparation steps required to bring the wood waste to a consistent composition and
moisture. Pellets made in Noah America are produced w/o added adhesives, thus the
process as it has developed today requires no additives, but rather uses the natural
adhesives present in the wood to bind the pellet together.

There are a number of important characteristics of wood that impact on the pellet
formation. For simplicity's sake and as far as the pelleting process is concerned, wood is
made of three basic components;

1. Cellulose - in laymans terms, the fibre which constitutes 40 to 50% of the wood
composition.
2. Hemicelluloses - constitutes 20 to 35%.
3. Lignins -which constitute 15 to 35%

The self bonding of wood to form a pellet involves the thermo-plastic flow of the
polymeric material, basically the lignin and hemicelluloses naturally occurring in the
wood feedstock. These materials that serve as the glue in the process, become plastic and
flows at specific conditions of temperature and moisture.

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Views: 4035 Added: 02-07-2008

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How pellets are formed