THE wood pellets are increasingly popular as a renewable and environmentally friendly energy source. To guarantee their performance and durability, it is essential to select the right binder during their manufacture. In this article, we will present to you the different types of binders available on the market and their respective advantages.
The role of the binder in the manufacture of wood pellets
The main function of the binder is to agglomerate the wood particles together to form a solid and resistant pellet. It also makes it possible to improve the cohesion of the pellets during their combustion, thus avoiding the formation of clinker and other undesirable residues.
The addition of a binder to the raw material (sawdust, shavings or chips) generally occurs before the pressing stage. The resulting mixture is then compressed under high pressure using a pellet press, which gives the granules their final shape.
The binder we recommend for the manufacture of quality pellets
The different types of binders for wood pellets
There are several categories of binders used in the manufacture of wood pellets, each presenting different specificities and performances:
- Natural binders: they come from the lignin contained in the wood itself, which is released under the effect of heat and pressure during the compression stage.
- Synthetic resins: they come from petrochemicals and can be added to the raw material to improve the cohesion and resistance of the pellets. There are several types of resins adapted to different wood species (softwood, hardwood) and manufacturing processes.
- Organic binders: they are made from substances of plant or animal origin, such as starches, proteins or even tannins.
Natural binders: lignin as a binding agent
Lignin is a substance present in the cell walls of wood, which gives it its rigidity and strength. During the pellet manufacturing process, heat and pressure release this lignin, which then acts as a natural binder by solidifying the pellets. This method does not require the addition of additional binders and offers a 100% natural product.
However, the lignin content varies depending on the wood species and their quality, which can impact the performance of the pellets obtained. In addition, certain raw materials, such as wood chips from the paper industry, contain less lignin and therefore require the addition of an external binder to optimize the quality of the pellets.
Synthetic resins: a solution to improve the performance of pellets
Synthetic resins are chemicals that improve the cohesion and strength of wood pellets. They can be added to the raw material to complement or replace natural lignin.
These binders offer a clear advantage in terms of performance, since they make it possible to produce granules that are more homogeneous and resistant to humidity. However, their use raises environmental and health questions, because these substances can generate polluting emissions during the combustion of pellets.
Organic binders: an ecological alternative to synthetic resins
Organic binders constitute a more environmentally friendly solution than synthetic resins. Coming from renewable resources, they also have the advantage of being biodegradable.
Among the organic binders, we find in particular:
- Starches, extracted from cereals such as wheat, corn or rice;
- Proteins, obtained from animal or vegetable meals;
- Tannins, present in the bark of certain types of wood such as oak or chestnut.
Although these binders offer an interesting alternative to synthetic resins, it should nevertheless be noted that they can be more expensive to produce and less efficient in terms of cohesion and resistance of the granules.
How to choose the right binder for the manufacture of wood pellets?
To choose the binder suited to your needs, several criteria must be taken into account:
- Raw materials : depending on the type of wood used and its lignin content, it may be necessary to add an external binder to guarantee the quality of the pellets.
- Environmental impact: favor natural or organic binders if you want to minimize your ecological footprint.
- The cost : Prices vary depending on the type of binder and the quantity required. Do not hesitate to compare the offers available on the market.
- Performances : certain binders make it possible to produce more resistant and homogeneous granules, which can prove useful in certain industrial or domestic applications.
What are Binders and Why Are They Important in Pellet Manufacturing?
Types of Binders Used in Pellet Production
Natural binders: lignin
Lignin, naturally present in wood, is the most common binder in the manufacture of pellets. Under the action of heat and pressure during pelletization, the lignin melts slightly and coats the wood particles, allowing them to bond naturally upon cooling.
Commercial binders: organic and inorganic
Commercial binders are also used, particularly for biomasses with a low lignin content. These binders can be organic, like starches, or inorganic, like clays. They must be chosen carefully to avoid negatively affecting the quality of pellet combustion.
How Binders Improve Pellet Quality
Improved mechanical resistance
Good mechanical strength is essential to minimize pellet degradation during transport and use. Binders play a crucial role in achieving this strength.
Reduction of operational costs
Although adding binders represents an additional cost, it can lead to savings by reducing the formation of dust and debris, which can affect the performance of combustion systems and result in maintenance costs.
Impact on combustion properties
Suitable binders can improve combustion efficiency, reducing emissions and increasing the calorific value of the pellets.
Choice of Binders: Balance Between Cost and Effectiveness
Cost-benefit analysis of binders
Cost-benefit analysis is necessary to balance the initial investment in binders with the improvements they bring to pellet production and use.
Finding the right binder ratio
It is crucial to determine the optimal binder ratio, which ensures quality without unnecessarily adding to production costs.
Environmental Considerations and Regulations
Impact of binders on the ecological footprint
Binders must be chosen taking into account their life cycle and their impact on the environment, to maintain the ecological credentials of the pellets.
Compliance with environmental standards
Pellet producers must ensure that the use of binders complies with current environmental legislation, including regulations on emissions and sustainability.
Innovation and Research on Binders for Pellets
Current Trends in Binder Research
The research aims to develop more efficient, more economical and more environmentally friendly binders, in order to meet the growing needs of the renewable energy industry.
Use of by-products as innovative binders
Exploring the use of industrial by-products as binders offers a promising avenue to reduce costs and environmental impact.
Tips for Pellet Producers
Evaluation of the raw material for the choice of binders
A thorough examination of the characteristics of the raw material is essential to select the most suitable binder.
Best practices for integrating binders into production
Adopting best practices for binder integration can greatly improve the efficiency of the pelletizing process and the quality of the finished pellet.
Conclusion
Judicious selection and use of binders is fundamental to producing premium wood pellets. An informed choice can significantly influence the sustainability, energy performance and market acceptance of wood pellets.
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