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Description of Pellet Produce Procedure
In industries, the procedure of wood pellets production mainly departs in the following steps: wood material crushing, water moisture control, biomass pelletizing, wood pellets cooling, wood pellets weighing and packing. In a wood pellet line, the pelletizing process is the most important. Equaling to the pelletizing part, the die and the roller is the most important part in a pellet machine.
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Wood material crushing:
As a general rule, the size of raw material should always smaller than the pellets size. For wood logs or round wood, crushing process by a wood crusher is needed. Then the smaller wood blocks will be fed into the wood chipper to chip the wood into chips for further use. If you want to make pellets with a size of 6mm, or smaller, you will need a wood hammer mill to make the wood chips into wood sawdust with a size not bigger than 6mm.
To make premium wood pellets, the water moisture of the raw material should be about 12%. So it is necessary to remove excess water from the raw material. In industrial pellets production, a wood pellet cooler is usually adopted. For small-scale, You choose to dry the material in the sun or other methods.
Wood material through a feeder come into the pelletizing room, where the die and the rollers are motioning relatively at a high speed. With the extrusion force and the high temperature forming in the relative motion, the intermolecular forces in wood material molecule have changed. Thus the plasticity of the wood materials has increased. Then the materials are shaped into pellets by the hole on the die and pushed out.
The pellets come out of the pellet machine is hot and wet. A pellet cooler is used to bring the temperature down and reduce the water content. After cooling, they are harder and easier to store or transport.