Lignin is a kind of main ingredient of wood pellet material, such as wood, sawdust, and wheat straws, branches, which can be made to fuel pellets by pellet press machine.
Lignin is a complex carbohydrate 'sugar' found in the cell walls of all cellulosic plant material. Lignin is central to the plants mechanical strength. Therefore, the more lignin the stronger the plant are in general. So different cellulosic materials have different percentages of lignin, for example, wood has a lot, and straw has a lot less, which makes sense in relation to mechanical strength.
During the process of pellet pressing lignin is what binds the material together to form a pellet; therefore, it makes sense that the more lignin presented the mechanically stronger the pellet can be made by pellet press machine. Therefore, wood pellets are generally harder and stronger than straw pellets. Therefore, a raw material with a higher percentage of lignin is less likely to require a binder and more likely to produce mechanically strong pellets.
Under the heat and pressure of the pellet press equipments the lignin melts and binds the material together to form a pellet. Once the pellet leaves the pellet press machine, the lignin begins to solidify and cool, producing a hard dense pellet.
