Tree branches from landscaping, discarded orchard trimmings, and forestry residues may seem unremarkable, but through a series of processing steps, they can be transformed into fuel pellets that are highly efficient to burn, easy to transport, and versatile in use.
So, what exactly are the steps involved in turning tree branches into fuel pellets?
🌿The first step is to collect raw material in the form of branches, including:
To ensure the quality of the pellets, it is necessary to remove foreign objects—such as stones, wire, and plastic—as much as possible to prevent them from interfering with the operation of downstream equipment.
Due to their large volume and irregular shapes, tree branches cannot be pelletized directly and must first be processed by a branch crusher.
The resulting wood chips are more uniform in size, which not only facilitates transport but also improves the efficiency of subsequent grinding stages.
The primary functions of this step are:
The wood chips require further processing into fine wood particles.
It is generally required that the wood particles be relatively uniform in size; this facilitates the molding process in the pellet mill and helps reduce equipment wear.
If the sawdust is too wet, the pellets tend to crumble; if it is too dry, they do not form well.
Typically, drying equipment or natural air-drying is used to adjust the moisture content to a level suitable for pelletizing, resulting in pellets that are denser and have a better appearance.
As sawdust enters the biomass pellet mill, the natural lignin within the wood softens under high temperature and pressure, acting as a natural binder to compress the sawdust into cylindrical fuel pellets.
Typically, the entire process requires no added chemical binders, making it more environmentally friendly.
The freshly produced granules are at a high temperature and require cooling.
They then undergo screening to separate out the powder and substandard granules, before finally being packaged for storage or sold directly.
Granules produced in this way are more robust, resistant to breakage, and convenient to transport.
Branch Feedstock Pelletizing Comparison
| Raw Material Type | Pelletizing Difficulty | Pellet Quality | Common Sources |
|---|---|---|---|
| Poplar and willow branches | ★☆☆ | Good pellet formation | Landscaping, riverbank trimming |
| Pine and fir branches | ★★☆ | High calorific value; contains resin | Forestry harvesting, wood processing |
| Fruit tree branches (apple, pear, peach, etc.) | ★★☆ | High density; stable combustion | Orchard pruning |
| Shrub branches | ★★★ | Requires thorough grinding before pelletizing | Municipal landscaping |
| Mixed garden branches | ★★☆ | Suitable for large-scale production | Landscape maintenance companies |
Compared to direct burning or disposal, producing fuel pellets offers several advantages:
Tree branch pelletizing involves collection, crushing, pulverizing, moisture adjustment, pressing, cooling, and packaging—with every step critical to quality. Biomass energy turns waste branches into a valuable resource, supporting green energy.
