In this article we will discuss how wood pellets are made. Pellets can be made from many forms of biomass besides wood including paper, cardboard, grain, straw, corn husks, yard wastes and more. The process for making pellets from all these materials is basically the same but in this article we will focus on making wood pellets.
A pellet is simply material that has been compressed into a pellet form and held together with a binding agent. With some materials the binding Order wood pellets & briquettes agents are naturally occurring but in others they have to be added.
Made into a pellet it is broken
Before wood can be made into a pellet it is broken down into small pieces like sawdust. To do this larger pieces of wood can be run through a chipper. Most chips are still too large so a hammer mill can be used to break them down even more.
The pellets are made by pressing this material into a pellet die. A die is a piece of metal that is full of pellet sized holes. The top of the holes are tapered like a funnel so as the material is pressed deeper into the hole it gets compressed as the hole becomes smaller.
The compression and friction heats the pellet and melts the binding compounds. As soon as the pellets are extruded out of the other side of the die they cool and the binding compounds harden and act like a glue that holds the pellet together.
Some materials like softwood have enough natural lignins in them that work as a binder. But other materials need to have some kind of binder added. These are usually organic materials like vegetable oil, flour and corn starch.
Pellet to form properly
In order for a pellet to form properly the material must be dry but still have some moisture. Depending on the material it should be somewhere between 10 and 20% moisture content. In most cases if the material isn’t already air dried to the proper moisture level it will have to be dried in a dryer. Dryers are usually the most energy intensive and costly part of the process so a lot of dryers are fired by the mill’s own pellets.
This is a brief summary of how wood pellets are made. Making pellets is a little like cooking in that sometimes you have to experiment a little to get them to come out just right. Now that small scale pellet mills are available home owners and businesses can make their own pellets for their own heating or to sell.
How to Make Wood Pellets For Yourself Or to Sell
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
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 pellets kaufen. 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.
