Beginner’s Guide to Wood Pellet Production

Raw Material Preparation:

In order to produce wood pellet, you need to prepare a variety of raw materials such as round logs, planks, branches, chips, shavings, sawdust, leaves, and wood waste from sawmills.(Related Article:how-are-softwood-pellets-different-from-hardwood-pellets)

Production equipment:

A range of equipment is required to produce wood pellets, including wood crushers, wood sawdust dryers, wood pellet mills, pellet coolers, and automatic balers.

Production Process:

The production process of wood pellets consists of the following steps: raw material crushing, moisture control, biomass pelletizing, pellet cooling, weighing and baling. In the whole production line, the pelletizing process is the most critical. In the pellet mill, molds and rollers are the core components.

Raw material crushing:

The size of the feedstock is usually smaller than the size of the pellets. For round wood or logs, they need to be crushed with a wood crusher first. The smaller pieces are then fed into a wood chipper to be further chipped into chips for subsequent use. If you intend to produce pellets of 6 mm or smaller, then you will need a wood hammer mill to process the chips into wood shavings no larger than 6 mm.

Moisture control:

In order to produce high quality wood pellets, the moisture in the feedstock should be controlled to approximately 12%. Therefore, excess moisture needs to be removed from the raw material. In industrial-scale production, a wood pellet cooler is usually used. For small-scale production, you can opt for drying in the sun or other drying methods.

Biomass Pelletizing:

The wood feedstock enters the pelletizing chamber through a feeder in which the dies and rollers move at relatively high speeds. The squeezing forces and high temperatures generated during this relative motion cause a change in the intermolecular forces between the wood feedstock molecules, thereby increasing the plasticity of the wood feedstock. Subsequently, the feedstock is extruded through the holes in the die into a granular form and pushed out.

Wood pellet cooling:

The pellets extruded from the pellet mill are hot and moist. The use of a pellet cooler lowers its temperature and reduces the moisture content. The cooled pellets are harder and easier to store and transport.

Weighing and baling wood pellets:

Using a pellet baler allows the pellets to be packed in plastic bags at the same weight for easy transportation or sale. For large quantities of wood pellets, a bulk truck is required. Bulk pellets are loaded directly from the pellet mill into a truck and transported to a bulk storage container. Although bulk trucks are more expensive than regular flatbed trucks, this is a more efficient processing system.