Part of what is fueling a recent increase in interest in pellet heat is more people are learning how to make wood pellets on a small scale. We can show you how wood pellets are made and how you can get started making them yourself.
Pellets are simply wood or any other biomass that is compressed into a dense pellet form. Pellets can be made from just about any fibrous biomass including grasses, grains and other agricultural wastes. The process is basically the same for making pellets out of any biomass but we will use wood as the example in this article.
First you start with raw material like sawdust. Larger pieces of wood will have to be broken down using either a chipper or a hammer mill and sometimes both. Typical wood chips are too big so a hammer mill is often used to break them down more.
In order for the pelletizing process to work properly the wood must be dried but still needs to have some moisture. Depending on the material being used 10-20% moisture content is about right. If you can’t air dry it to that point you will need a dryer. These are often fired by burning pellets and have the added benefit of pre heating the material before it gets to the mill. The added heat can make it easier to form a pellet.
Some materials have enough natural binding compounds in them. These compounds act like a glue that will hold the finished pellet together. With some materials and with some mills that don’t produce enough heat in the pellet production may need additional binders such as flour, corn starch, vegetable oil or other binding agents.
The pellet mill uses a roller that works similar to a rolling pin to press the material into a die. A die is a metal surface that has many holes that are the same size as the desired pellets. The opening of the holes are tapered like a funnel so when the material is pressed in it gets compressed as the size of the hole gets smaller.
The pressure and friction generates heat which melts the binders in the wood. When the pellet comes out the other end of the die it cools and the binding agents harden and you then have a finished pellet.
Making wood pellets is a little more involved than cutting standard firewood but with a little practice and some trial and error you can learn how to make wood pellets pretty easily with the right knowledge and tools.