Do you know what the most efficient and environmentally friendly energy source is? Well, yes, it is biomass palletizing. It is a process where pellets are made from biomass. It is the best method to transform organic materials into a reliable source of energy.
There are many factors that affect the production of pellets. One of the main factors is the effect of particle size on the durability of pellets. It has a key role in maintaining the physicochemical properties of biomass when converted into pellet fuel.
In this detailed article, we will look into the mechanical properties of biomass pellets and the effect of particle size on biofuel pellet properties.
Defining Particle Size in Biomass Pelletizing
By the term particle size, we mean the dimensions of raw material used in creating straw pellets. It is an important factor since it decides the final form of pellets produced. Particle size has a direct effect on the density and porosity of a single pellet. In addition to this, it also affects the combustion characteristics of the resulting pellets.
Impact of Particle Size on Pellet Density
The most important effect of particle size of densified biomass is on the density of pellets obtained. If the particle size is large, you will get pellets with lower density. This is because of its impact on the energy content per unit volume.
If you want to produce pellets of optimal size, keep in view the particle size of biomass. Only then can you produce pellets with high density. This will help you produce a more efficient and cost-effective energy source.
Particle Size and Compression
There is a strong relation between the particle size of agricultural biomass and compression. The particles that are smaller in size have larger surface areas. It helps in the better binding process, resulting in biomass densification. An increase in particle size will result in size reduction of fuel pellets from biomass.
Another important thing to consider is that compaction of biomass can cause friction. An increase in friction will produce heat during the production of pellets. You need to keep a balance between large and small grain sizes. Make sure you use effective compression to achieve the required particle density. Only then can you maintain the quality of pellets.
Influence of Binder Interaction on Properties of Biomass
In the process of producing pellets, we use different binders. These binders help enhance cohesion between the particles of biomass. The size has a large effect on the interaction between the woody biomass and binder material.
When we have smaller particle sizes, it offers a larger surface area. This large surface area helps provide an area for the adhesion of the binder. As a result, a strong connection is formed between the particles.
However, if you are using large waste biomass, you will have to add more binder solutions. Only then can you get effective cohesion between the molecules.
Effect on Combustion Efficiency
Another important effect of particle size is on combustion. It is important that all the particles from different types of biomass are of equal sizes. Only then will they be equally combusted in biomass boilers or furnaces of the palletizing machine.
If the particles are of irregular sizes, the combustion will be irregular. As a result, it will affect both the output biofuel pellets made and the longevity of the combustion process.
Remember that fine particles tend to burn fast. Particles of large size may burn incompletely. As a result, you will get excessive emissions, and it will decrease the efficiency of the process.
What is the Ideal Particle Size Range of Pellets?
The ideal size for particles of raw material for pellets depends on many factors. Some of the important factors are the type of biomass material, the type of Pelletization process, and the end use of these pellets. Here, we will discuss some general details that will help us decide on a good particle size range to produce high-quality pellets:
Fine Particles (Fines)
To increase the pellet quality, you need to use fine particles. These are particles with a size less than 1mm. They help in a good and strong binding between the raw material and binder. As a result, the palletization process improves.
If you add a good percentage of binders, it also improves the binding between particles. As a result, you will be able to increase the durability and density of pellets.
Standard Particle Size Range
The standard particle size range for most biomass pellet applications is around 1mm to 10mm. If the particles of raw material fall in this range, it will help increase the pellet strength. Also, the process of combustion will improve.
Type of Biomass Material
Different biomass materials may have specific requirements. Wood pellets, for example, often have a standard size range, while agricultural residues or grasses might have different optimal particle size considerations.
Fibrous materials may require additional attention to ensure effective binding due to their unique structural characteristics.
Pelletization Process
The Pelletization method employed, whether it’s a flat die or ring die pellet mill, can influence the ideal particle size. Some processes may be better suited for specific particle size distributions.
Adjusting the parameters of the Pelletization equipment allows producers to fine-tune the particle size and optimize the Pelletization process.
End-Use Considerations
The intended application of the pellets is a crucial factor. For instance, pellets used for residential heating in pellet stoves may have different size requirements compared to those used in industrial biomass boilers.
Matching the particle size to the combustion system ensures efficient and clean burning.
Process of Wood Pellet Production
A roller acting on the material squeezes the material into the stamp. The stamp itself has a resistance. This resistance prevents fluid from passing through the holes in the stamp. The pressure wielded by the roller is combined with the frictional pressure generated by the formulation itself.
This pressure causes the material to be squeezed. It prevents the material from coming out along the surface of the stamp in front of the roll.
As we increase the adjustment of the variable speed drive or control and increase the feed rate of the biomass pelletizer, the amount of material increases in the form of the front of the roll.
In other words, it is essential to push the material into the pressure roller intrusion point with a large force instead of falling into the pressure.
Conclusion
As we have discussed above, particle size is one of the important factors that decide the end quality of pellets. It helps improve the binding mechanism of densified biomass. If you need more details about particle size and how you can work on it, you can contact us.