Best Practices for Making High Quality Wood Pellets
Wood pellets are used as a renewable source of fuel, which can be used instead of coal or other fossil fuels. Since their invention they have been made to heat people’s homes, billow steam into the sky, and even power engines running ships across oceans. When it comes to making quality wood pellets, you need a quality output. The best practices for making high-quality wood pellets addresses all of the most common ways that wood pellet producers can improve their wood pellet production. There are vast improvements that can be made provided the producer follows the advice in this guide.
1. Keep the moisture content of your raw material uniform and low.
The moisture content of your raw material is one of the most important factors when it comes to making wood pellets. A poor raw material can have a negative impact to the final quality of your pellets. It’s therefore worth taking time to learn about how to avoid high moisture content in your raw material and how to manage the moisture content during storage and transport. The main section provides an overview of what causes high moisture content in wood pellets and how you can align the drying process with pellet production. The last section steps through some common moisture measurement methods, and why you should use one method over another.
2. Don’t use wood from painted or chemically treated sources.
There are particular pieces of woods which should not be used in the production of wood pellets. Woods from which pellets are made from should be dried, kilned and cut down to size while leaving their natural color intact. You must avoid using chemically treated, paints or other wood sources with any sort of coating or paint.
3. Grind your raw material to a uniform size.
When you’re grinding your own raw material – like sawdust, for example – to produce wood pellets, it is important that you have the right size and distribution of particles. Otherwise, you might run into problems downstream. If the particle size distribution (PSD) is too broad and your raw material has a wide variance in particle sizes, you may need to break them down further before you get to the pellet mill.
4. Dry your wood until it has an appropriate moisture content for pellet making, usually around 18% – 25%.
Drying wood until it has an appropriate moisture content for pellet making, usually around 18% – 25%, is important to ensure that your pellet mill operates at its optimal levels. When wood is cut and left outside in a pile, it will quickly start to lose timber moisture. In the process of drying, the moisture is taken away from the cells of the wood which causes them to shrink in size. Timber moisture content (or MC) measures the water inside the cells of dry material in relation to its dry mass (1). The MC value is then expressed as a percentage. A high water content is undesirable because it can lead to problems in drying as well as other processing steps such as pelletizing (2)
5. Don’t grind your pellets in advance of pelletizing them.
Most people will wish to grind up the pellets so that the contents have a reliable uniformity of size. There is more to it than that, though. As a matter of fact, it is advisable to not grind the pellets in advance of pelletizing them. Avoid this mistake if you want to make the best pellets ever.
The main reason for this is that grinding will increase the risk of loss of nutrients in your feed. This can happen when those nutrients are broken down into smaller particles through grinding. This means that instead of getting all the nutrients you need from your feed, you may end up getting less than what’s required by your livestock.
Pelletizing is also important because it reduces dust levels during storage and transportation as well as increases shelf life due to moisture absorption by pellets during storage.
6. Prevent foreign objects from entering the pelleting chamber with proper screening and magnetic separation measures.
The presence of foreign objects in food products can cause contamination and lead to product recalls. To ensure that all materials entering your pelleting machine are screened and properly separated, follow these steps:
1. Inspect incoming ingredients for foreign objects using a metal detector.
2. Screen incoming ingredients on an inspection table to remove any large pieces that may have escaped detection by the metal detector.
3. Separate out any small pieces that may have been missed by either of these methods with a magnetic separator.
7. Store finished pellets properly to prevent the pellets from absorbing moisture and contaminating themselves with dust and dirt generated during handling, loading and unloading operations.
Be aware of the fact that moisture can cause a considerable amount of damage to your pellets. If you do not store them properly, they will become wet, which will lead to mold development, which in turn can cause serious health problems in humans who consume the product.
If you want to keep your pellets dry so they don’t get contaminated with dirt or dust particles that might have been brought into contact with them during handling operations such as loading or unloading, then make sure that you store them correctly after processing has been completed.
The simplest conclusion to draw here is that there is no simple formula for producing high quality wood pellets. For some, this may be discouraging, but the truth is that it was never expected to be as simple as plug and play. Pellets today have a variety of uses, from heating your home to fueling your car; reaching these goals requires creative thinking in an ever-changing marketplace, and will always require a bit of trial and error on the part of producers.