Wood Pallets have gained immense popularity as an alternative fuel in recent years, due to their low cost, easy availability and ecological properties. This blog is all about manufacturing process of wood pellets. So here are 11 steps to get the perfect wood pellets.
Where do wooden pallets come from?
Pellets can be created from many different types of waste materials, such as wood chips, paper scraps, crop straw, agricultural and forestry by-products. In this section, we will focus on the processes involved in making wood pellets. Producing pellets from a variety of materials follows very similar steps
Manufacturing of Wood Pellets
Wood pellets are often manufactured in factories. Most wood pellet mills require the wood to be converted to sawdust first. High-density pellets can be created by compressing raw materials via die holes.
Pellet mill processing can be used to melt lignin in wood products by creating heat via compression and friction. After passing through the die, the wood pellets will gradually cool. The lignin in the sawdust solidifies into pellets when it cools. Here’s the whole process.
- Raw Materials Crushing
To make wood pellets, the raw materials must be small enough to be fed into the die. If your raw materials are bigger than an inch, you’ll need to run them through a hammer mill or a wood chipper to reduce their size. With a hammer mill, the size can be reduced from 10-30 mm to 3-5 mm. Certain raw materials, like sawdust, don’t need to go through this stage because they are already fine enough.
- Unprocessed Material Transportation
For more modest operations, raw materials can be crushed by hand before being fed into the pellet mill. Due to the need for transmission during mass production and along the wood pellet production line, a screw conveyor or belt conveyor is typically used. They connect several pieces of equipment, making them essential to the production of pellets. With an automatic conveyor, the transmission speed may be held constant, and the raw materials need not be piled.
- Drying Out The Raw Material
When making wood pellets, the raw materials must be completely dried. The ideal moisture content for raw materials is between 10% and 20%. Overly dry raw materials will be difficult to form. If the wood pellets are excessively wet, they will be impossible to work with.
The unprocessed materials can be hung outside to dry in the air flow. Nevertheless, wood pellet plants use airflow dryers and drum dryers to rapidly dry the pellets.
You can also read : What is a biomass wood pellet?
- Mixing Unsorted Materials
Raw ingredients for high-quality wood pellets should be consistent. That is to say, they should look and feel the same and have the same amount of moisture and bulk. Raw materials should be stored in conditions that isolate their density and moisture content. This problem can be avoided if pellets are produced from the same raw materials and through the same pretreatment operations using the same equipment and approaches. If the raw materials have varied characteristics, they should be blended or mixed in a rotary drum, both of which should be placed in the mixing feeder.
- Altering the Original Sources
For the raw ingredients to be usable as wood pellets, the fibres must be bound together using natural lignin. For instance, rice husks are a raw material that can’t self-organize into anything useful. They need to be glued or somehow linked together.
- If raw materials are too dry, they might be sprayed with water or mixed with other products that already contain more moisture.
- Certain raw materials need to be preheated to increase their adhesive force and plasticity. The dryer machine can usually be used to heat the raw materials. In spite of this, a large wood pellet mill uses dry steams to heat the raw components
- Creating wood pellets
- This stage is essential in the pellet-making process. Pellet machines come in two distinct types: ring die and flat die.
- The roller in a pellet machine with a flat die is an integral part of the die. In this machine, raw materials are fed in and rotated while being pushed into holes on a flat die to create solid, spherical
pellets. A slicer positioned below a flat die was used to cut the wood pellets to consistent lengths.
- For pellet machines that use a ring die, the roller is contained within the ring die. Raw materials are pushed through the ring die’s slots using an outward force.
- Sorting Pellets of Wood
Unfortunately, not all pellets produced are usable. Sieving is required to get rid of the shattered pellets. Sifting can also be used to separate pellets of varied sizes. Pellets are sifted using a vibrating sifter.
- Condensing Wood shavings
When they first come out of the pellet mill, wood pellets can be boiling hot. You can let them sit in the open air for a while to cool down. A wind blower or a fan can be used to speed up the cooling process. A counter-flow chiller is used to cool the wood pellets made in large factories. Once wood pellets have cooled, they become more sturdy. However, the wood pellets will crack if the drying process is rushed.
- Carrying Wood Pellets
The wood pellets are then transferred to a packing machine where they are prepared for sale. Wood pellets shouldn’t be transported using a screw conveyor due to the risk of pellet damage. We frequently use a bucket elevator for pellet transportation.
- Wood Pellet Containers
Up until this moment, wood pellets have been produced. Wood pellets need to be packed before being stored or transported to save them from moisture or contamination. The pellet packing machine can be used to customise the bag size for packing particle materials. It’s a good idea to use waterproof bags. If you use these, your wood pellets will stay dry. The availability of vast storage silos allows for the storage and sale of wood pellets in large quantities.
- Tools for pellet packaging
The procedures described above are not required. Crushing and drying are typical preparation steps for most materials; combining and altering are not. The pellets of the product, meanwhile, require no more processing.
If you are looking forward to getting the best quality wood pellets to make get cost-effective and ecological energy, contact Shreeji Renewable Energies. Our wood pellet plants use latest technology and quality raw material to give our customers consistent quality in every batch of wood pellets.