How Low Can Moisture Go An Still Make Quality Wood Pellet?

When it comes to the advantages of wood pellets over other biomass fuels such as logs and wood chips, one has been the low moisture content of the fuel. A lower moisture content means a higher combustion efficiency, quick ignition and less smoke. However how low can you go with moisture? Well the dryers used in the pellet plant could take the moisture content down to virtually zero, however you would not want to for several reasons. Firstly dealing with a dust with virtual no moisture is extremely dangerous and could easily lead to a fire or even worse a dust explosion. Also as a fuel do do actually want a small amount of moisture present, otherwise you cannot really control the rate of burn. In terms of the pellet mill you definitely need some moisture present to produce quality wood pellets, however as with many aspects the right amount of moisture can make all the difference. While the objective is to produce wood fuel pellet with a moisture content to around 6%, up to 10% is acceptable. The first objective is sufficient pellet density. With soft pellets you can have greatly reduced combustion results with a lower temperature and also more ash.  A low density pellet wastes potential energy, and can also create issues with excessive fines. With a good density pellet you should be able to put is under reasonable horizontal force before it breaks, and when it breaks it should be clean with little dust. The exact amount of moisture present in the pellet mill effects the relationship of temperature and compression. Therefore it effects the density of the pellet and also how well the fibres have bonded together. With smaller pellet mill you generally need to have slightly more moisture in the raw material 13-15%. With larger pellet mills you can often get away with a moisture content around 10%. Its always best to experiment with the mill you are using to find what percentage gives you the best pellet density.

 The Wood Pellet Mill Production Guide  - How Low Can Moisture Go And Still Make Quality Wood Pellets?