Getting Your Wood

Down To Size

If you are looking to make pellets, the first process that should get your attention is not making pellets in the pellet mill but preparing the raw material for the pellet mill. The quality of the pellet and the efficient operation of the pellet mill is only as good as your material preparation. Part of that preparation is size reduction. Generally you want to reduce your wood down to particle size of about 5mm, and this must be fairly consistent. Oversized particles may struggle to run through the pellet mill die properly to form a pellet. The current state of you raw material will dictate what equipment you need. If you have sawdust already this maybe suitable to go straight into the pellet mill, however generally its best to pass it through the hammer mill to guarantee a consistent particle size. Also if possible the material should be passed over a magnet. A good way to do this is to have a magnet in the cyclone separator after the hammer mill. Metal can cause serious damage in the pellet mill, and a magnet would remove the risk. However it does not remove the risk from stones or any other hard objects, therefore its always important to try and keep the material as clean from contaminates as possible. If you already have your wood in chipped form this could also be loaded directly into the hammer mill. However try not to process very wet chips through the hammer mill. The hammer mill works on attrition, the force and speed of the hammer it what breaks the wood into smaller pieces. Wet material absorbs this energy, and does not break cleanly. From experience this can quickly block up the hammer mill screen. If you wood is above chips size for instance still in log form you will require a chipper. This does mean generally you have to go through two steps of size reduction from the chipper to the shredder. There are combined hammer mill chippers, where the machine chips the wood which enter the centre of the hammer mill. However again wet material will not pass through a fine 5mm screen, so wet logs (which they usually are) will create issues. So as you can see size reduction is the first step.

 The Wood Pellet Production Guide © PelHeat Ltd - Getting Your Wood Down To Size