Pellets are granules from compressed woodworking and agricultural waste. They are produced without the use of chemical additives, therefore they are considered an environmentally friendly source of energy. Pellets can be produced from any raw material that contains lignin. The raw material for them is coniferous wood.
The hardwood fuel pellets made from deciduous trees (oak, birch) are better in quality, but require more complicated equipment for production. And wood, chips, sawdust, and bark go into production. The granules quality depends on the composition of the raw materials. If they have a lot of bark, which is usually contaminated with sand, then the quality of granules will be inferior to purely wood ones. You can press pellets from a mixture of wood waste, or you can only from sawdust or wood.
According to the degree of purification, pellets are divided into three grades:
- the highest;
The higher the grade of pellets, the less ash they produce during combustion and, accordingly, the less often cleaning is required.
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Benefits of Wooden Pellet Heating
Pellet heating has a number of undeniable advantages in comparison with other solid fuel types.
- Environmental friendliness. In the production of pellets no chemical additives are used, only natural raw materials.
- Low price. A kilo of top-grade pellets costs an average of 8-10 rubles, which is about 50% cheaper diesel fuel in terms of heat transfer during combustion.
- High heat dissipation. The efficiency of pellets reaches 94%, and exceeds the efficiency of dry wood and peat.
- Autonomy. Heating equipment, working on pellets, allows you to provide heat to private houses not connected to the grid.
- Autofeed. Boilers working on pellets are equipped with automatic feeding devices. One load is enough for 4-5 days.
- Convenience. Pellets are supplied in polyethylene bags and are easy to transport and store.
- Ease of use. Pellet equipment requires almost no maintenance, except for occasional
- ash cleaning
Dry sawdust and shavings are considered ideal to be raw materials for producing high-quality pellets. They usually have no bark inclusions as well as soil particles, which form slag during combustion. The quality of wood chips as a raw material for pellets depends on what kind of wood it is obtained from (ordinary or debarked), and also on its storage conditions. The less bark and foreign inclusions gets into the pellets, the lower their ash content, and therefore higher quality.
What is an Alternative Raw Material for Pellets?
The pellets can also be produced from different materials, such as:
- Waste of the agro-industrial complex: legume pods, corn cobs, rice husks, buckwheat, husks, sunflower, flax bonfire, nut shells, fruit pits, bard, unsimilar grain, spent grains.
- Plants: reeds, straw, sugar cane, as well as trees and shrubs cut down during landscaping works and sanitary cuttings.
- Other natural combustible substances: peat, lignin.
These materials are amenable to granulation, but compared to wood, they have a number of disadvantages:
- undesirable chemical compounds;
- high ash content;
- low melting point of ash residues.
This leads to the growth of slag formations in boilers. So hardwood wood pellets are the best option for usage in heating systems. It prevents malfunctions and extensive depreciation of equipment.