How The Pellet Mill Responds To Moisture

There is much more to making quality pellets than most people think, particularly when it comes to moisture. If someone has done no research at all into how pellets are made they may not be away that most biomass materials are too wet to start with to work in the pellet mill.

For instance we get questions like 'Can I chip my wood and then use it in the pellet mill' most wood which is chipped is virgin timber, so you are looking at around 50% moisture, maybe more. Generally that's about 35% too much moisture for the pellet mill. Now we generally state that around 15% moisture is right, however this a general recommendation. The fact is each material is different, some require a bit more moisture and others a bit less or a lot less. The moisture percentage required in the final pellet depends on its intended use, say for instance its a fuel pellet. You want a moisture content between 6-10%, this will create a hot and controlled burn producing no visible smoke. However do not always presume that a material with 15% moisture will produce the pellet you want and the pellet mill operating the way you want. Moisture effects pellet compression and temperature, therefore it affects how well the lignin melts and the density of the pellet. As moisture effects the resistance of the material through the pellet mill die, it also effects the productivity and energy consumption of the pellet mill. This has been observed in many studies, the productivity is easy to measure and energy consumption can also easily be calculated by watching the amp meter gauge on the pellet mill motor. Observations have shown that a 2% change in moisture from 14% up to 16% caused productivity to drop by 30% and energy consumption to increase by roughly the same amount. Please click below for our videos.