This is my main post on the subject of how wood pellets are made. Within this post, you will also find links to other posts on the process of making wood pellets. For instance, more details on material preparation, how the pellet mill works etc. It’s best to start with reading this post however as it provides a broad overview of the wood pellet making process. You will learn that while it may appear to involve simply placing wood within a pellet mill, this couldn’t be further from the truth.
You will learn that even small changes in the particle size of the wood placed into pellet mill can make a big difference. You will also learn about why controlling the moisture content of the wood plays a crucial role. Consistently producing good quality durable wood pellets is a challenge. It requires a will prepared raw material and an equally well prepared and maintained pellet mill. If either of these factors are not truly appreciated the results can be a lot of wasted time and frustration.
Once you own a pellet mill and the start to try and make wood pellets for the first time it’s more than likely you will run into issues. One of the most common issues is a blocked wood pellet mill die. With this post, I discuss some of the reasons the die can become blocked, and how to avoid it happening again. The die is the most important part of the pellet mill when it comes to making wood pellets. The design of the die and how it is maintained have significant consequences on the process of making wood pellets.
When it comes to making wood pellets there is a lot of discussion and debate around the topic of binders and lubricants. For instance, does a small pellet mill require a pellet binder to make wood pellets? The answer depends on several factors, such as the design and quality of the pellet mill. However, pellet binders and lubricants are actually common in the wood pellet industry. Only small amounts are required which can have a big impact on wood pellet making process. It is possible to make wood pellets without binders, but they can make the process run a lot more smoothly.
You can make wood pellets from practically any source of woody biomass. However, some raw materials will produce wood pellets not fit for purposes depending on their intended use. For instance, the requirements of wood pellets used for heating fuel are very different for those used for animal bedding. Furthermore, wood pellets used in BBQs are also very different than those used for heating fuel or animal bedding. There are also certain raw materials you should not process. Either because it will potentially damage the pellet mill or by using/burning the wood pellets could be a health hazard. There is a lot to think about when choosing the best raw material to make wood pellets from. This includes evaluating how close that raw material is to where you will process it with a pellet mill.
When it comes to making wood pellets, probably the biggest headache comes from the issue of moisture content. If the raw material is too dry or too wet wood pellets will not form. Furthermore, too much moisture can easily lead to a pellet mill die blockage. Then more time needs to be spent to clean the die before you can try again. Therefore trying to figure out what is the perfect moisture content for the raw material to produce wood pellets is one question. The second is how do you get the raw material to that particular moisture content. On a large scale wood pellet plant its fairly straight forward. There are in-line infrared moisture meters and batch mixers to produce a consistent material. On a small scale, however, these luxuries are not viable. Therefore it involves low tech options such as dry weight tests.
You may have a source of logs available or you know of a cheap source of logs and are looking to the process of making wood pellets. What you need to be aware of is that processing logs into wood pellets can present significant challenges. You will need to understand your end users requirements and whether you need to remove the bark from the logs. Removing the bark takes additional time, effort and equipment, but it may be required. In other cases leaving the bark on the wood pellets may even improve the end product.