The experience of European countries in the use of pellets demonstrates the effectiveness of this type of fuel in terms of heating function, as well as the economic feasibility of its use. In Russia, this resource is less popular, but the conditions of energy supply make it turn to new consumers. Promotes the distribution of pellets and the development of manufacturing technologies, which allows to expand the range. Some modifications of heating boilers are designed for the combined use of fuel. This eliminates the risks of switching to a new combustible material and facilitates the operation of the equipment. To answer the question: "Pellets - what is it?" - it is necessary to consider production technologies, the raw materials used and the characteristics of this type of fuel.
General information about pellets
Pellet composition usually includes logging waste (bark, wood chips, sawdust), but there are other varieties of raw materials, including agricultural processing products. Depending on the formulation, the pellets may include waste from straw, corn, sunflower, as well as cereal elements, droppings, etc. The presence of such a list of components may seem doubtful in terms of energy efficiency, but this is another question: pellets - what is it from the point of view applications in the heating system? They are rightly called fuel granules, in which there are no toxic and synthetic components. Again, depending on the composition, the consumer receives a fuel product with minimal ash factors and is environmentally friendly.
Production technology
The production chain is quite short, which makes it possible to produce pellets on their own. Of course, special equipment will also be required, but so far it is worth considering the stages of production:
- Preparation of the raw material base. As a rule, special crushers are used.
- Drying. The semi-finished product is placed in a drum or tape chamber, where it acquires a sufficient indicator of humidity - an average of 10%.
- Grinding the finished mass through hammer mills .
- Water or steam hydration. Screw mixers are used for efficient bonding during pressing.
- Next, a pellet press is used, which can be a cylindrical or flat design, suggesting further cooling of the workpiece.
- Filtration and packaging of pellets.
Indisputable advantages of wood pellet manufacturing technology include non-waste. It is a rarity even in the wood processing industry, which produces heating products. In the traditional version, the pellet production line involves only one stage of control for marriage - screening. But the filtered granules are not disposed of, but are used in subsequent manufacturing cycles.
Equipment for the production of pellets
There are various configurations for the technical organization of production lines for fuel pellets. They can be combined at the expense of individual industrial plants or use ready-made mini-granulators. Conveyors also differ in the type of drive - electric, diesel, gasoline, etc. One way or another, the most important element that the pellet production line has is a granulator. This unit often replaces the work of full-fledged crushers and presses.
Also, depending on the volume of production and the raw materials used, chip cutting (crushing solid wood waste), drying equipment and a semi-finished product cooler may be required. All the described operations are able to perform a multifunctional machine for pellets, which can work on one of the common types of raw materials. However, the cost of such equipment is quite high - at least 300-400 thousand rubles.
Pellet boilers
To date, a whole class of heating equipment has been formed, designed for the consumption of biofuels. The device of most boilers in addition to the housing provides for the following elements:
- Fireboxes.
- Burners.
- Fuel compartment.
- Heat exchanger.
- Smoke exhaust.
As you can see, the pellet stove in terms of structural design repeats the usual wood-fired boilers, but there are fundamental differences. In many ways, they come down to the parameters of a combustion chamber with a small space. The fact is that heat transfer is carried out in the complex convective part of the unit, which makes it possible to ensure considerable efficiency - an average of 80%. Rational combustion is also facilitated by the design of the burner, which makes the boiler function more productive and more economical.
Varieties of boilers
Despite the relative novelty, heating systems for pellets have already managed to take shape in the form of several types:
- Models focused on working exclusively with fuel pellets.
- Combined units. The device of the furnace in such boilers implies the possibility of transformation, which, in addition to pellets, allows the use of conventional solid fuel materials. However, the main type of fuel for such equipment is still bio granules.
- A universal pellet stove, as a rule, has several combustion chambers, each of which in its characteristics is capable of taking a certain type of fuel.
Regardless of the type of pellet boiler, almost all modern models provide extensive programming and automation capabilities. Automation is also provided in the pellet feed system from the hopper. The combustion chamber is supplied almost without human control - as needed and while there is a supply of pellets.
Where are pellets used?
Again, according to the experience of European countries, it can be said that granular fuel is universal. It is used to service district boiler houses, and in private. However, in Russia many still have a question: pellets - what is it? Fuel for industrial facilities or a means for heating private homes? In fact, this biofuel can not only be used as an alternative to gas and firewood, but also show better results of energy supply.
By the way, fuel pellets are actively used in regions where there is no stable provision of trunk networks. Independent heating of the house with pellets gives significant advantages for remote cottage villages. In addition to the heating function, pellets are able to perform the tasks of eliminating liquid products. This is due to their use as fillers for pets toilets, as well as in the elimination of emergency sites during flooding.
Sustainability and the secret of efficiency
This kind of biofuel, of course, has many advantages, but some of them are exaggerated, which is misleading to the consumer. One of the myths comes from the high efficiency of the granules, which is supposedly possible only if artificial modifiers are added that exclude the product’s environmental friendliness. Indeed, the production of fuel pellets in some formulations involves the introduction of chemical additives. However, in Russia, production standards completely eliminate this, and optimal combustion performance is achieved due to low humidity and high density.
Storage conditions for pellets
Perhaps this is one of the main disadvantages of fuel pellets. They require the creation of special storage conditions. In any case, the requirements in this regard are tougher than for traditional solid fuel materials. To understand the nuances of storage, it is important to remember: pellets - what is it. These are compressed crushed wood particles, in the creation of which there are no binding components. Therefore, any exposure to moisture can lead to the destruction of the granules. Even without direct contact with water, long-term storage on the street will result in pellets being saturated with moisture from the air. Accordingly, it is advisable to store biofuels of this type only in rooms where there is no dampness and temperature changes.
Conclusion
If you take into account all the advantages of fuel pellets, then the question will rightly arise why they are still perceived only as an alternative to gas and firewood? This is partly due to the fact that wide layers of consumers do not yet know about pellets, although the situation is changing. The expansion of production, the introduction of new technologies for the production of biofuels and the emergence of efficient boilers for fuel pellets increase consumer interest in this topic. So the questions arise regarding the rejection of firewood, coal and gas: can they be replaced by pellets? Reviews have not yet given an unambiguous assessment.
Obviously, there are advantages in the form of ergonomics of the use of pellet boilers, high efficiency and safety. But there are also disadvantages, among which consumers highlight the high prices of boiler equipment, problems of their compatibility with imported fuel pellets and the search for stable suppliers. In some cases, the savings are not so certain. For example, if there is a choice between wood and pellets, then the second option in terms of cost reduction is fully justified. However, compared with gas, biofuels are not so profitable. Nevertheless, if it is not possible to connect to the central supply lines, then granules become the only economical choice.