Before you can make wood pellets you obviously have to have a source of raw material to process. A question I’ve been asked repeatedly over the years is ‘what is the best raw material to make wood pellets?‘ Well to answer that question we need to think about what the wood pellets will be used for. For instance, will the wood pellets be used for heating fuel, animal bedding or BBQs?
Your choice of raw material is probably the most impact factor that will dictate how successful your project is. For instance, is your raw material free or will you have to pay for it? Are there sufficient amounts of this raw material close to where you will make the pellets? How reliable is the supply of this raw material? Resolving all these questions should be the first thing you do before you purchase any equipment such as a pellet mill. Furthermore, how you prepare that raw material can also influence potential issues such as a blocked pellet mill die. Below I’ll go through the different potential uses for wood pellets and how that will influence your choice of raw material.
The Best Raw Material For Fuel Wood Pellets?
In terms of making wood pellets to be used as fuel, you need to focus on the end user and their pellet burning appliance. For instance, will end user be using a small pellet stove or large industrial pellet boiler? Pellet stoves are generally less tolerant to higher ash content wood pellets, where large scale boilers have systems to deal with higher percentages of ash content.
What Effects the Ash Content of Wood Pellets?
The ash content of the pellets is primarily impacted by the choice of raw material. For instance, if you want to achieve the highest standard of wood pellets then you want to avoid wood bark. Wood bark increases the ash content of the wood pellets over the ‘premium zone’ of 1-2%. Therefore if you wish to process logs, you first need to remove the bark. However, if your raw material is wood chips, removing bark is not going to be possible. Therefore, your available raw material will dictate which end users can use the wood pellets for fuel. It will obviously also impact the value per ton of the wood pellets.
There are small pellet stoves which can handle ‘standard’ grade wood pellets with an ash content over 2%, however, it is a small percentage of the pellet stove market. Therefore if you are looking for your largest potential customer base you will need a raw material with little to no bark.
Avoid Making Wood Fuel Pellets from Processed Materials
Over the years I’ve often been asked if materials such as MDF and Chipboard can be used to make wood pellets. While these materials can be processed into wood pellets, I would not recommend that you do so for fuel pellets. The emissions generated from burning these wood pellets can be quite dangerous, and potentially illegal. This also includes making wood pellets from painted wood.
The Best Raw Material For Animal Bedding Wood Pellets?
With animal bedding wood pellets, ash content is obviously not a concern. Therefore it is possible to use logs and wood chip which still contains bark. The absorbency of the pellets is not dictated by the source of wood. However, there are other factors to consider. As stated above with fuel pellets, do not use processed wood as the raw material. Using such a raw material could create health complications for the animal. Therefore you only want to use virgin raw materials. This could be logs, wood chips, shavings or sawdust.
The Best Raw Material For BBQ Wood Pellets?
Particularly when it comes to BBQ wood pellets no form of painted of processed wood should be used. The smoke from BBQ wood pellets provides the food with a great flavour, but you don’t want that flavour to be toxic chemicals. In terms of the type of wood you can use for BBQ wood pellet there are many to choose from. It could be Apple, Cherry, Oak, Hickory and Alder to name just a few. In terms of bark with BBQ wood pellets its a bit different, it can actually provide a benefit. The bark of the wood can produce some of the best flavours in the food. Wood pellet BBQ’s don’t actually burn significant amounts of wood pellets, therefore there are less potential issues with ash build up.
IMPORTANT: Avoid Contaminated Wood!
So above we talked about avoiding processed/painted wood. Well, there is another raw material you should also avoid. If the raw material may be contaminated with stones or metal you should not consider processing it. Even small pieces of stone or metal can cause serious damage to a pellet mill. Best case scenario is some minor damage to the rollers and die which will need replacing. The worst-case scenario is it could cause significant and expensive damage to the pellet mill drive system/gearbox and pellet mill motor.
Ideally, You Want To Find a Dry Raw Material
If you have a large pellet plant and dryer, you can process wet (above 15% moisture) wood into pellets. However, it still costs money to do so. On a small scale, however, there are very limited options to dry wood to below 15% to process into pellets. Therefore really you need to find a dry raw material. Now back 20 years ago there used to be clean/dry sawdust freely available. For some companies, it was even regarded as a waste product. As such, they would actually pay to have it taken away. Well, times have changed, and most companies who produce such material today realise its value. Therefore now they are either processing it themselves into wood pellets or briquettes, or they are charging for it.
A Local Source of Raw Material to Make Wood Pellets
When it comes to a wood pellet businesses the most significant costs are haulage of the raw material and finished wood pellets to customers. Those that have gone out of business it has often been due to increasing transportation costs. Searching further afield to find suitable raw materials and having to transport wood pellets over longer distances kills profit margins. Therefore finding a suitable source of raw material local to where you intend to make the wood pellets is vital.
Conclusions on the Best Raw Materials To Make Wood Pellets From
Really before you even consider purchasing a pellet mill or pellet plant you need to be confident in your raw material. First, you need to find a raw material that will suit your end users. You then want to make sure it’s not processed wood, it’s free from contamination and ideally dry. Finally, the location of the raw material and how you will get it to your pellet mill/plant is important. Keeping transportation costs under control will be vital to the success of your project.