So if you’ve started looking into how to make wood pellets, you may have come across the discussions over the use of binders. So in this post, I’ll discuss what binders are and if you’ll need them to make wood pellets.
A pellet binder is an additional material which will be mixed into your raw woody biomass material to aid the process of making pellets. A typical example would be a form of modified corn starch in powdered form. The benefits of using a binder can be increased pellet mill productivity, improved pellet quality, improved roller and die life and finally reduced energy consumption. Pellet binders can also help to provide lubrication to the process and reduce the likelihood of a blocked pellet mill die.
Water and Vegetable Oil for Making Pellets
So first and foremost before using a pellet binder, your attention should focus on water and vegetable oil. If the pellets are exiting the pellet mill in a dry crumbly form adding in a small amount of water to the process can improve pellet quality. The additional water will do two things. It will increase the compression within the die and also increase temperature. This in term will help to melt the natural lignin within the wood to help the pellets form. However, adding too much moisture can generate too much pressure, leading to a blocked pellet mill die.
Adding in small amounts of vegetable oil into the pellet making process can help to lubricate the pellet mill die. This can avoid a pellet mill die blockage by keeping the compression generated under control. However, adding too much vegetable oil will significantly reduce the density of the wood pellets produced. Therefore their density will not be sufficient to withstand packaging and transport. So the addition of vegetable oil should be used sparingly and with care.
What Different Types of Pellet Binder Are Available?
In the feed pellet industry, there are many different types and brands of pellet binder available. They not only aid the pellet making process but they can also add nutritional value to the feed pellets. However, with wood pellet production, if a binder is used more than likely it would be a form of modified corn starch.
Matam Inc Pellet Binders
One manufacturer of modified corn starch pellet binders is Matam Inc with its product PelletBond. It is designed to act as both a wood pellet binder and pellet mill lubricant. The further benefits of the pellet binder being reduced pellet mill energy consumption and increase productivity simultaneously. This product can be particularly useful when trying to make wood pellets with a small pellet mill. The reason being with a small pellet mill it’s harder to get up to the optimum operating temperature to make wood pellets.
Borregaard Pellet Binders
Another pellet binder manufacture is Borregaard with its product Lignotech. This product is heavily used in the animal feed pellet industry, however, it could also potentially be used in wood pellet production. The pellet binder comes in 25kg brown paper bags and its in the form of a powder. Therefore to be able to use this pellet binder you need a way to add in very small and precise amounts of powder into the raw material and pellet mill.
Kiotechagil/Anpario Pellet Binders
Kiotechagil developed a pellet binder called Mastercube, however, it now appears to be produced by Anpario. This pellet binder can do some of the work of producing the pellet chemically instead of purely mechanically with the pellet mill. Therefore, again this presents the benefit of reduced pellet mill energy consumption. Mastercube is produced from plant gums and mineral hardeners. It can help to produce a harder more durable pellet while improving pellet consistency. Mastercube is a popular pellet binder for animal feed pellet plants. However, for wood pellet production I would use a modified corn starch product such as PelletBond.
How Much Binder is Required When Making Wood Pellets?
Typically between 1-3% of the raw material to make wood pellets is made up of a binder when making wood pellets. Therefore the actual impact on cost per ton is very minimal.
Small Pellet Mills Benefit Most From Pellet Binders
So as you may have gathered from the information above, pellet binders make the process of making pellets simpler. It can take some of the work away from the pellet mill to aid in the process and make good quality pellets. This is a particular benefit for small pellet mills, particularly those purchased from China. For the following reasons:
Small Pellet Mill Operating Temperatures and Binders
To produce good quality wood pellets the pellet mill die needs to get over 80 degrees Celsius, this can be quite tricky for small pellet mills. Therefore, adding in 1-3% pellet binder into the raw material mix can be the difference between a small pellet mill making wood pellets at all.
Small Pellet Mill Dies for Wood Pellets
When you purchase a small pellet mill from China, for instance, the machine arrives with a single die. Now, really to make wood pellets you want a pellet mill die with a specific compression ratio to suit that raw material. As this is not provided with many small pellet mills from China, you have to work with what you’ve got. Therefore, through using a pellet binder it’s possible (partially) get around the issue of a die not being ideal for making wood pellets.
Furthermore, the dies that come with small pellet mills from China are often drilled to a poor standard. Rough die holes mean a high likelihood of a blocked pellet mill die. Therefore, a pellet binder can also help to lubricate the process and reduce the odds of a blocked die.
Conclusions on Pellet Binders for Making Wood Pellets
Large scale wood pellet manufacturing facilities do often use a small percentage of a pellet binder such as PelletBond, however, it is more of optional extra. With their equipment, they are able to control the pellet making process precisely in terms of particle size and importantly moisture content. On a small scale, however, it is much more difficult to keep the variables under control at all times. For instance, even when using a binder the moisture content of the raw material is very important. When it comes to making wood pellets on a small scale the use of a pellet binder is less of an option. In fact, I would say if you intend to purchase a small pellet mill from China, for instance, a pellet binder is essential to make wood pellets.