How Does the wood Sawdust Pellet Making Machine Achieve Pellet Forming?

 

 

First, let's clarify the core principle: Wood chips contain natural lignin, a high-molecular-weight compound that is hard at room temperature and acts as a binder between wood chip fibers. When the temperature rises to 70-110℃, lignin softens into a molten state, exhibiting excellent viscosity and becoming a natural "adhesive." Under the extrusion pressure of the equipment, the softened lignin coats each wood chip fiber, binding the dispersed fibers together. After cooling, the lignin hardens again, forming solid wood chip particles. The entire working process of the Wood Chip Pellet maker Machine is essentially a process of "softening lignin through extrusion heating or external heating, then using extrusion to allow the lignin to fully exert its binding effect, ultimately shaping the chip."

 

The equipment utilizes two key design features to facilitate lignin softening and binding: firstly, extrusion heating, which is the most crucial heat source. Whether using a flat die or ring die machine, strong extrusion force is generated between the pressure roller and the die. During extrusion, intense friction occurs between the wood pellets and between the pellets and the inner wall of the die. The heat generated by this friction rapidly raises the raw material temperature to 70-90℃, precisely meeting the temperature requirements for lignin softening. For example, the extrusion pressure of a flat die machine can reach 10-15 MPa, and the frictional heat temperature can be stabilized at around 80℃, requiring no additional heating. Small ring die wood pellet making machines have even higher extrusion pressures (15-25 MPa), and the frictional heat temperature can reach 90-100℃, further enhancing the lignin softening effect.

 

Secondly, structural design improves the extrusion effect, allowing lignin to fully exert its binding effect. The pressure rollers of the equipment have anti-slip textures to increase friction with the raw material, preventing slippage, enhancing frictional heat generation, and providing more even extrusion pressure. The die orifices feature a tapering design with a large inlet and a small outlet, resulting in gradually increasing extrusion pressure on the raw material as it enters the orifice. This allows lignin to fill the fiber gaps more fully, leading to stronger bonding. The ring die machine's conditioner actively raises the raw material temperature through external heating (steam), softening the lignin beforehand and reducing the pressure from subsequent extrusion heat generation. It also increases the material's viscosity, making molding easier.

 

Two key factors affect the lignin softening effect and require careful control during equipment operation: First, the raw material moisture content, ideally between 12% and 15%. Excessive moisture content reduces frictional heat generation, resulting in insufficient temperature and inadequate lignin softening. Insufficient moisture content leads to poor material viscosity, making it difficult to bond the fibers even after softening. Second, the raw material particle size needs to be controlled between 2-5mm. If the particle size is too large, frictional heating will be uneven, resulting in insufficient softening of lignin in certain areas; if the particle size is too small, energy consumption will increase, and the raw material bulk density will be low, leading to poor extrusion performance.

 

Understanding this core principle allows users to precisely control the parameters of the small biomass pellet maker machine and the raw material pretreatment standards. For example, when processing hardwood chips (low lignin content), the extrusion pressure or temperature can be appropriately increased to ensure sufficient softening of lignin; when processing softwood chips (high lignin content), the extrusion pressure can be appropriately reduced to avoid energy waste.

 

 

 

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1.What is the price of equipment for the homemade sawdust pellet machine?

It costs approximately US$1,500.00 - 25,000.00

 

2. If equipments have some quality problem, how would you deal with?
We will responsible for all the quality problems. Change all the parts for free.

 

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