What are pellets and what are they for?

Heating with ordinary wood

Firewood has been used for heating for a very long time; it is high-quality fuel for a house and a bath, barbecue and barbecue. The environmental friendliness of firewood will always be at the level of 100%, and this fuel has plenty of other advantages. Let's note the main advantages of firewood, without delving deeply into this topic:

• First of all, I would like to say that the process of harvesting, drying and storing firewood is understandable for everyone. From an early age we know how to look for firewood, collect and light it.
• It is not difficult to light wood,. Some varieties of trees can burn in high humidity, giving off heat.
• The cost of firewood is small, even if you do not go through the entire harvesting cycle, but buy ready-made poles or logs. (However, until the moment of comparing prices of different fuels, it will not be argued which is more profitable.)
• Firewood is not afraid of mechanical damage and can be completely different.
• From an aesthetic point of view, the wood burns perfectly. They create a beautiful fire and a soulful crackle, and when some varieties are burned, a characteristic pleasant aroma appears. For open fireplaces, where the appearance of what is happening is important, such fuel is considered optimal.
• The substances released during the combustion of firewood have a beneficial effect on a person, they calm the nervous system, heal the respiratory system.

Strategic forest reserve for the winter

We will also highlight the disadvantages of natural fuel:

• To obtain a high heat transfer, the wood must be well dried under natural conditions, which takes an extremely long time, for example, 1 or 2 years. The best firewood is wood that has been in a dry shed for a couple of years.
• With long-term storage, wood loses some of its qualities, especially aromatic varieties of trees.
• Firewood takes up a lot of space, for their normal storage in the proper amount, it is necessary to build an appropriate structure.
• When using firewood, a lot of debris always appears (chips, bark, wood dust, sawdust).

Now that we are familiar with the basic capabilities of the two fuels, let's make a comparison.

Note

1. Calorific value measurement in Kcal / kg. It is generally known that 1 (one) calorie is the amount of heat required to heat one gram of water by one degree. The meaning of this physical quantity is completely understandable and it is already easy to imagine how much heat is needed to heat a bucket of water 4,500 Cal / kg. (4,500 Cal / kg) is the heat of combustion of a kilogram of our fuel in Calories.
2. Calorific value measurement in MJ / kg. System International Thermal Unit. Its physical meaning can only be expressed in terms of a calorie. 1 Calorie equals 4.19 Joule. (4.500 Kcal / kg. * 4.19 Joule = 18.855 MJ / kg.) - the heat of combustion of a kilogram of our fuel in Joules.
3. Calorific value measurement in kW / h. In power engineering, it is customary to measure electrical and thermal energy in kW / hour. 5,238 kW hour / kg - the calorific value of a kilogram of our fuel, measured in "electrical units". How did this value come about? If a kilogram of this fuel is burned in an hour, then it is not difficult to calculate how much energy was released every second, that is, what thermal power was generated in this case. Divide 18.855.000 J (see point 2) by 3600 seconds and get 5238 J / sec. those. 5,238 kW

In particular, the following advantages of this type of biofuel can be highlighted:

• Low price. Compared to any other energy sources, especially hydrocarbons, this fuel is much cheaper. Accordingly, it is possible to more economically solve the issue of heating and heating.Moreover, the solution is relevant both for a country house (organization of a heating boiler) and for industrial facilities (preparation of water at the required temperature and heating of workshops). Another important factor is the absence of pressure on the market price of the international factor. If Kiev buys pellets exclusively at an internal price formed on the basis of domestic supply and demand, then coal and gas are supplied to the consumer at prices dictated by the world market.
• Advantageous physical and chemical properties of the material. Wood pellets have a high calorific value, which allows achieving high boiler performance with low fuel consumption. In addition, when burning pellets, little ash is formed, therefore pellet boilers are not too capricious and require a minimum of maintenance.
• Fuel structure efficient from the point of view of combustion physics. Since pellets are a mound of individual elements, they burn very well, because the best catalyst - air - is contained directly in the structure of the bulk material. Accordingly, the fuel can be considered universal; it does not require any additional processing before use. Such fuel is no worse than gas or coal.
• Wood pellets are an almost unlimited resource. If oil is equated with black gold, and gas is the cause of international scandals, then low-grade wood, as well as waste from the woodworking industry, is in abundance. Therefore, this resource is always available on the market without any problems.
• Ecological cleanliness. Burning pellets does not lead to emissions of any harmful substances, fully complies with the most stringent standards for emissions of carbon dioxide, as well as any other gases into the atmosphere. Accordingly, pellets are not only profitable, but also a green technology.
• Convenient combustion process. Modern pellet boilers have a high degree of automation, which allows you to switch to this type of fuel without any technical difficulties. A pellet boiler requires no more attention than a coal boiler.
• When burning 1.9 tons of pellets, approximately the same amount of heat is released as when burning one ton of fuel oil, while the cost of pellets on the domestic market is three times cheaper. Thus, heating with pellets is 40% cheaper than fuel oil.

Definition of what pellets for heating are and their features

Pellets are compressed pellets of a cylindrical size, the material for which is waste from the wood, coal or agricultural industries. So for pellets sawdust, shavings, thyrsu, coal chips, sunflower husks are used. With the help of special equipment, fuel can be made from waste. At the same time, pellet heating is considered environmentally friendly.

There are many advantages of pellets. First of all, their low cost is distinguished.

A lot of heat is generated during the combustion of pellets. In this case, the fuel completely burns out, leaving a minimum percentage of ash. Fuel transportation, as well as its storage, does not cause any difficulties and problems.

Different types of wood are used for pellets. This can only affect the size of the granules. Typically, the diameter of the fuel is 6-8 mm and the length is 5-7 mm. The fuel is quite dense, the pellets sink into the liquid. When buying pellets, you should check their quality. Some manufacturers add sand to the chips, which increases their weight. Deception can be detected by burning several granules, sand will be immediately noticeable in the remains.

The smoke from burning pellets has no aroma. Also, there is no sulfur in the material of manufacture. That is why, when they are burned, sulfur dioxide does not enter the air.

Where pellets burn

Heating boilers for pellets belong to the class of solid fuel boilers. They have a robust housing with a combustion chamber and heat exchanger.Combustion of fuel pellets leads to the release of hot combustion products, which passing through the heat exchanger give it (and it is the heat carrier) heat.

"Born" back in 1947, pellet boilers have grown significantly in terms of efficiency and "intellectual" development. Pellet boilers today are fully automated systems capable of "relieving" a person from the duties of a stoker for quite a long time (up to a month or more). It all depends on the size of the bunker or warehouse for storing pellets. The self-cleaning function allows you not to "interfere" with the life of a high-quality boiler during the entire heating period.

An important factor in the distribution of fuel pellet boilers is their high environmental friendliness. After all, pellets are recycled wood, and the process of their combustion occurs with minimal release of harmful by-products. In fact, this is a waste-free "production".

Pellet boilers, having a high efficiency, a long period of operation, autonomy (from a person), also have a high cost. But the cost of pellets in a few years compensates for the investment in the boiler. The consumption of pellets for heating can be determined from the ratio: to obtain 5 kW of heat, it is necessary to burn 1 kg of pellets. A house with an area of ​​100 square meters will require 20-25 kg of pellets for its heating.

If necessary, such boilers can be heated with wood, coal, wood chips, straw waste, etc.

The "reverse" application is also possible. If you have a ready-made stove or fireplace, you can heat them with pellets. Recalling the analysis of the properties of fuel pellets, it can be argued that a pellet stove will have a higher efficiency than when working with wood.

How pellets are made from wood pellets

For the production of pellets, they take the most inexpensive wood that cannot be used for any other purpose. These are trimmings, chips, sawdust. This waste is sorted, cleaned of impurities, sand is sifted out, etc. Further, the powerful magnet used on the sorting belt attracts iron (eg nails). After removing foreign objects, the wood waste is sent to a hammer mill, where it is crushed to fragments of 4 mm in size. This stage is called pre-grinding. It is necessary for uniform drying of raw materials at the next stage.

Pellets are made and waste from the woodworking industry and agricultural complex

The resulting sawdust is dried in a special bin to the required moisture content (8–12%). Then they are sent for re-grinding. As a result, small pieces of wood are obtained, which, after bringing to the ideal moisture content (10%), are sent to a pellet press. Here, under the influence of pressure (in some high temperature presses) the sawdust is transformed into pellets. For this, the composition is passed through a matrix in which round holes are cut. The design of the press-granulator resembles a conventional meat grinder: the dough is pressed through the holes, and granules are obtained. They are cooled in a cooling column. This is how the final product is obtained - fuel pellets.

Pellets history of creation

The word pellets is of English origin and literally means - granules. For those who still do not quite understand what is at stake, I will explain: pellets are small cylindrical granules made from waste from the woodworking industry and agriculture. They are used as solid fuel in direct combustion systems or gas-fired units.

The first person who thought to "squeeze" the wood and give it a more convenient form for transportation was the Bavarian Rudolf Gunnerman, who later set up the production of the first pellets in the USA.The products turned out to be very profitable, especially since for the production of fuel pellets it was possible to use free raw materials such as peat, sawdust, shavings and other waste from the woodworking industry, as well as straw, corn and sunflower stalks, husks and other plant matter. In America, they began to show interest in this type of fuel, since, in addition to its efficiency, it presented a number of advantages, one of which was ease of transportation and high bulk density. These benefits are still valid today. For example, the same peat, due to its low density, does not make sense to transport more than 100 km from the mining site, since in this case transportation costs will exceed the cost of the fuel itself. If peat is compressed 5-7 times, as it happens in the process of pellet production, then long-distance transportation becomes justified.

Today in America more than 80 large enterprises are engaged in the production of fuel pellets. Annual production amounts to over 1 million tons, which are absorbed mainly by the US domestic market. In addition, the United States purchases about 40% of its pellet consumption abroad (mainly in Canada). The popularity of fuel pellets in America has led to the development of technologies for efficient combustion of pellets. Today, more than 20 American companies are engaged in the production of equipment operating on pellets, which also supply their products for export.

The popularizer of pellets and a kind of Columbus who brought American technologies to Europe was Sweden, which in 1985 established the production of fuel pellets from waste of the woodworking industry. With the arrival of the nineties, the pellet boom spreads throughout Europe and by the end of the century they are already being produced in England, Italy, Norway, the Netherlands, France, Finland, Denmark and Germany. Today, most of the waste of European woodworking enterprises goes to the production of pellets.

The high environmental friendliness of this type of fuel played a significant role in the popularity of fuel pellets. As with burning wood, pellets emit exactly as much carbon dioxide into the atmosphere as the plant has absorbed during growth. However, imported fuel is always tested for the content of harmful impurities, since this type of fuel can be considered environmentally friendly only if wood or agricultural waste was grown in ecologically safe areas. So, in 2009, Italy discovered an increased content of cesium 137 in a batch of pellets from Lithuania, after which all 10,000 tons were returned to their "homeland". Meanwhile, pellets from Ukrainian producers are being successfully sold in Europe, despite the Chernobyl disaster. Today, 15 enterprises operate in this country, and almost all of their products are exported. For Russia, with its timber reserves and the number of woodworking options, the production of pellets is undoubtedly a profitable prospect, but so far this industry is at a development stage. China saw great prospects in the production of fuel pellets and has already embarked on a course for their production, planning to reach the level of 50 million tons per year by 2020. This is about ten times more than today's annual production of Russian pellets.

Briquettes vs pellets

The article examines certain aspects of the market for wood pellets and briquettes, taking into account the possibilities of their production in Russia.

The search for alternative energy sources and the development of the biofuel industry is becoming increasingly important in many countries of the world, where special programs are being developed for both producers and consumers aimed at enhancing the development of the market for environmentally friendly solid fuels. But Russia, possessing huge reserves of wood raw materials for the production of fuel pellets and briquettes, still remains on the sidelines of this process.

Briquettes: standards, production and use

Fuel briquettes are larger than pellets and have their own standards. By their use, briquettes are closer to ordinary firewood and coal, have a high density, so they are convenient to transport and store. There are three main types of briquettes (they are also the most widely used and popular among manufacturers):

1. RUF briquettes. They have the shape of a rectangle, the usual dimensions are 6.0 x 9.5 x 15 cm. They are made from crushed wood of any species (sawdust, chips, bark), do not contain adhesives and are optimal in terms of price and quality. They got their name from the name of RUF, the leader and founder of the production of hydraulic presses. Most of the enterprises producing briquettes work on RUF equipment, because this equipment has a large resource, unpretentious to raw materials and operating conditions. Also RUF presses are equipped with a system for adapting to raw materials and a briquette size control system. RUF equipment can operate in a "broken" mode with frequent stops.
2. Round fuel briquettes are produced on impact presses (NESTRO). They resemble ordinary firewood in shape. They are a cylinder with a diameter of 6 to 9 cm, a length of 5 to 35 cm. They are also produced from dry crushed wood and do not include any harmful adhesives. The difference in price and quality depends primarily on the density of the product. It is not possible to obtain a high density on non-professional equipment, therefore cheap briquettes are made in small sizes, otherwise they will be very fragile or simply fall apart under their own weight. The specificity of this equipment in its continuous operation is due to the specifics of the start and stop of the press.
3. Pini Kay briquettes. They have the shape of an irregular polyhedron with a hole in the center and a dark crust. The crust on the briquettes appears due to the fact that not only pressing, but also firing is used in the production process. Thanks to this, the pini-kei are resistant to moisture and quite durable. They have dimensions of 5-6 cm X 20-25 cm. Thanks to the hole in the center, the briquettes have three times the surface area, because of this they burn beautifully. These briquettes are classified as "Premium" because of their qualities, so their cost is slightly more expensive. The name, like that of RUF briquettes, comes from the name of the Austrian manufacturer of this type of equipment.

The European standard for fuel briquettes DiN 51731 was formed on the basis of the technical characteristics of a briquette made on a RUF press.

Eco Technologies Factory

Eco Technologies Plant LLC - a company with many years of experience supplies equipment and technologies for the production of biofuels and the processing of industrial waste. Eco Technologies Plant is a reliable supplier of equipment for the production of pellets, fuel briquettes, metal briquettes, as well as equipment for the complex processing of woodworking or metalworking waste - drying, crushing, separation and transportation.

More details on the website

The main producers of briquettes are currently Denmark, Germany and Austria. The technology for the production of fuel briquettes is mainly used: hydraulic presses (RUF), impact-mechanical (C.F. Nielsen) and extruder (Pini-kay).

The technological line for the production of fuel briquettes includes the following equipment:

• Dryer
• chopper
• press
• packing equipment

In fact, for the release of briquettes, one press is needed, into which shavings, dry sawdust, and crushed lumpy waste after rejection are fed. At the exit, a fuel briquette is obtained, which is packed and stacked on a pallet. The system is very reliable, there are no weak links in the technology, it is served by one person who is busy with the packaging.All equipment occupies 4 m2. The production area can be 20 sq. m.

It should be noted that the requirements for fuel briquettes are much lower than for pellets. There are no such strict quality requirements as for pellets. Since this material is not bulk, it is more convenient to pack and transport it. It is allowed to store briquettes in five floors, which makes it possible to efficiently use the storage space. In this regard, it becomes possible to supply it to Europe by large trucks with a high carrying capacity (a pallet with briquettes weighs about a ton).

The sales market for briquettes is focused on thermal power plants, boiler houses, industrial furnaces, railway transport and low-capacity boilers. briquettes are also in great demand among the population for heating small living quarters. Indeed, unlike pellets, briquettes can be burned in conventional solid fuel boilers. Today, fuel briquettes are becoming more and more widely used goods, and Russian manufacturers are active players in the domestic and world markets.

Pellets: standards, production and use

Any biofuel is obtained by pressing pre-dried and shredded wood, whether waste or other wood (sawdust, wood chips, bark, lump waste, sawmill and gouging waste). The process of producing pellets is technologically more complicated, it requires high quality raw materials and their careful preliminary processing, since in the future this may affect the quality of the product itself, the possibility of transportation and storage.

Different countries have their own quality standards for fuel pellets. Russia does not yet have its own standards and is often based on the German DIN PLUS standard.

The quality of wood pellets according to DIN data must meet the requirements:

• 5-6 mm in diameter
• 8-30mm in length
• the calorific value must exceed 18 MJ / kg = 5 kWh / kg = 3.25 kW / l
• bulk density 650 kg / m³
• the material must have a density of more than 1.12 kg / dm³
• water content less than 10%
• ash less than 0.5%

The dry wood pellet production line consists of the following units:

• raw material warehouse
• primary grinding
• warehouse of wet sawdust or chips
• Secondary crusher - hammer crusher with unloading device
• Dry material hopper
• Air conditioning
• Pellet press (granulator)
• Pellet cooler
• Sifter and system of return of screenings to technology
• Finished product hopper
• Big bag or bag packing system

All nodes are connected by elevators and conveyors, each of which costs money and is a potential weak link. The cost of the pellet press itself is less than 50% of the total set of equipment.

Various equipment is offered on the market, the variety is due to high demand. Here and recovered OGM granulators made in the USSR, Chinese products, pellet presses from Europe and combined options.

The storage costs for pellets are low, since safety measures can be significantly reduced, because there will be no oil stains or leaks. One of the main problems arising during the storage of granules is the presence of an always dry and ventilated room.

Since the pellets are quite small and free-flowing, they completely burn out in boilers, without requiring the constant presence of a person. In the west, most private houses, municipal and industrial boilers are equipped with pellet boilers. Today Europe is the most serious consumer of fuel pellets.

Pellet boilers are a fairly new type of heating device in the domestic market, but they are confidently gaining popularity. Russian-made models began to appear on sale, which are comparable in quality and much cheaper than their Western counterparts.

What is more profitable to produce?

When it comes to recycling wood waste, everyone knows the word pellets.This is a buzzword, everyone knows that biofuel in the form of pellets heats the whole of Europe. In Russia, on modern equipment, they are produced by the leading enterprises of the forestry industry. The attitude to fuel briquettes is somewhat different: “Yes, of course we are aware of it, but they seem to be cheaper and somehow we don’t hear about them”. So, what is more profitable to produce. The question is very individual and it can be solved only by knowing the specific components of a particular enterprise. We will try to provide data that can simplify your choice.

Comparative characteristics of fuel briquettes and pellets

Who and what produces

Large wood processing industries with a significant amount of waste, as a rule, have debarking technology and produce pellets for the export market. Enterprises where the waste is dry shavings obtained on four-side planing machines can also produce DIN PLUS pellets.

Pellets from lower quality raw materials are cheaper than briquettes from the same raw materials, and equipment is more complicated and expensive. As a result, the creation of a production of industrial pellets makes sense if there is an internal consumer in the form of a local boiler house or within the framework of some state programs.

If the goal is to utilize low-grade chips, slabs with bark in large production volumes, then, of course, it makes sense to look towards the production of consumer or industrial briquettes.

And so, the choice is yours!

The main advantages of fuel briquettes include

• Fuel briquettes obtained from vegetable raw materials are an environmentally friendly product. The material of the fuel briquette in full is natural raw materials. The binder is natural "living" lignin - a substance contained in the cells of dead plant materials.
• After heat treatment of raw materials in the production process of eurowood, they do not succumb to the influence of fungi.
• In comparison with natural firewood - Eurowood due to its higher density - burns longer. Therefore, it is possible to put briquettes in the oven (boiler) - 2-4 times less often.
• Due to their convenient shape, Eurodrova is very convenient to store and use.
• They have a high calorific value. Euro wood gives on average 2 times more heat in comparison with ordinary wood. Their calorific value is comparable to that of coal.
• During combustion, a constant temperature is provided at each stage of combustion due to an even flame.
• Ash content after briquettes combustion is in the range of 1-3%. For comparison: ash content after coal combustion: 30-40%, natural firewood combustion: 8-16%, wood chips: 11-18%. For this reason, those who work at the Europipe are cleaned once a year. At the same time, ash can be used as an environmentally friendly fertilizer.
• When burning fuel briquettes, poisonous carbon monoxide is not emitted and other harmful substances are not formed.
• When using Euro wood - heating costs are lower than in the case of using coal or natural wood.

There are 3 types of fuel briquettes:

1. RUF briquettes. RUF-briquette is a briquette in the form of a small rectangular brick.
2. NESTRO briquettes. NESTRO briquette is a cylindrical briquette. Can be with a radial hole inside.
3. Pini & Kay briquettes. Pini Cay briquette is a briquette with 4, 6 or 8 faces with a longitudinal radial hole inside.

Unit maintenance

The next important parameter that you need to pay attention to is the ash content of the fuel. This parameter determines the amount of waste that remains after fuel combustion. For coal of the highest quality, the ash content is at least 30%, that is, after burning 1 ton of fuel, at least 300 kg of ash remain. Naturally, it must be cleaned and taken out somewhere. If the boiler is used regularly, then such an activity will take a lot of time and effort. The situation is different with pellet boilers.

The ash content of the granules ranges from 1-3%. In other words, pellets burn almost completely. After burning 1 ton of pellets, about 10-30 kg of ash remains, which is 10 times less than from coal.

Firewood is a traditional fuel

First of all, firewood prepared from trees of various species is suitable for heating. They differ in structure, the ability to give off heat. The performance of the boiler will depend on this. The calorific value of firewood, depending on the type, fluctuates:

• 1600-3200 kcal, with an average humidity of up to 12 percent.
• If this indicator of humidity is higher, from 40 to 50 percent, then the calorific value decreases.

Moreover, fuel with high humidity will have to be pre-dried. This can be done by placing the stored fuel in special rooms with good ventilation.

Firewood is not cheap. For example, in the Moscow region per cubic meter you will have to pay at least 2 thousand rubles

... If the wood is split and well dried, then their cost is in the range of 4-5 thousand. It should be noted that when burning, firewood gives a large percentage of ash.

Selection of pellets for boiler plants

Industrial boilers are usually designed for heavy loads and are not as demanding on raw materials as their domestic counterparts. In order for the boiler to effectively provide heating of the house on the pellet, in addition to its type, you need to pay attention to the following technical indicators, which must be indicated by the manufacturer:

• Product moisture - for normal ignition and maintaining combustion should be within 8%, over 14% - the material is not suitable for use;
• Heat transfer during combustion - it is better if it is in the region of 4.5 and higher kcal / kg, like wood pellets, but 4.3 kcal / kg is also acceptable;
• Ash content of the product - has an upper tolerance threshold within 1%, if this limit is reduced to 0.5%, then the boiler can be cleaned no more than once a month.

In addition to all of the above, the pellets should be visually inspected for cracks.

High-quality material has a shiny surface, does not crumble and breaks with difficulty. When the granules are dipped into water, they should eventually turn into a soggy mass, if this did not happen, it is likely that a chemical adhesive component was used in their manufacture, which is unacceptable. The presence of coarse sediment of small stones and sand also indicates a poor quality of the product.

How to make money on pellets

This is not the subject of this article. But still, we want to note that for the organization of profitable production, access to wood waste in large quantities and a line with a pellet capacity of 2000 kg / h are required. The money invested in such a line will pay off in an average of 1-3 years.

But as they say, nothing is impossible. It is necessary to think, calculate and do!

Fuel loading

The wood-burning stove must be constantly looked after and the logs must be placed in a timely manner. In a harsh winter, with long nights, at least (and very likely), you will have to get up a couple of times. Pellet boilers are equipped with a special hopper. It is enough to load the pellets into it, and you can not approach the heating device for several days, or even weeks (depending on the model) - the automation independently feeds the pellets into the firebox as they burn out.

Microclimate regulation

The level of automation of wood-fired boilers is zero.Pellet counterparts, depending on the set temperature, themselves maintain it in the room, metering the supply of pellets to the firebox.

Output

3
- those who are used to comfort and value personal time should choose a pellet boiler.

Profitability

Despite the fact that pellets have almost the same calorific value as coal, heating them at home is quite costly. A ton of such fuel is on average more expensive than coal. Naturally, the price of coal will depend on the brand and calorific value. In addition, the price may vary significantly for different regions. On average, 1 ton of coal costs 3-7 thousand rubles, while 1 ton of pellets costs 6-8 thousand.

Also worth noting is the increased cost of pellet boilers. This is due to the fact that such boilers must be equipped with a special system for automatic fuel supply to the combustion chamber.

Features of heating with pellets

Pellet combustion indicators:

• Calorific value of pellets: 18 MJ / kg.
• Pellet boiler efficiency: 93-95%.
• Automation capability: yes.
• Pellet ash content: 0.5-3%.
• Pellet moisture content: 5-8%.

Just like firewood, this biofuel has its pros and cons.

Advantages of pellets

• Ecological cleanliness.
• Low cost, but higher than that of firewood.
• Operational safety (absolutely non-explosive).
• Low ash content.
• Ash recycling.
• Convenience of storage.
• High calorific value.
• High boiler efficiency.
• Ease of operation of pellet boilers.
• No need for a large warehouse.

Disadvantages of pellets

More expensive than firewood.

Heating with pellets is much more pleasant than with wood. Most modern boilers have a container into which the granules are filled with a reserve. Depending on the model, this stock may be enough for a day, week, month, or even the whole season. In this case, there is no need to control combustion.

Since the ash content of the pellets is low, no more than 20 kg of ash burns up during the whole season. The boiler is rarely cleaned (once a week or even a month), there will be no problems with the use of such an amount of ash, you can simply fertilize the backyard, flower garden, vegetable garden.

The owner of the pellet boiler does not need to worry about fuel preparation, the pellets are completely ready to be fed into the boiler.

Boiler autonomy

When making your choice between pellets and coal, you should not rely on cost alone. If we are talking about the constant use of the boiler for heating a house, then such a parameter as the autonomy of the boiler should be taken into account.

The temperature in the combustion chamber is very important for the heating system. Since most coal-fired boilers do not have an automatic fuel supply system, you have to independently monitor the state of the combustion chamber and toss the coal with your own hands. For a large house, it is necessary to load fuel several times a day, and even more often in severe frosts.

In pellet boilers, this problem is not so acute. They are equipped with a special automatic system, which itself determines the amount, as well as the intensity of the supply of granules to the combustion chamber. Such boilers have a special reservoir from which the pellets are fed into the firebox. Naturally, the frequency of loading depends on the outside temperature and the size of the tank itself, but on average it is once a week.

Coal grades B, D, G

Due to the high content of volatile substances, such coal quickly ignites and burns quickly. Coal of these grades is available and suitable for almost all types of boilers, however, for complete combustion, this coal must be supplied in small portions, so that the released volatiles have time to fully combine with atmospheric oxygen. Complete combustion of coal is characterized by a yellow flame and clear flue gases; incomplete combustion of volatile substances gives a crimson flame and black smoke.For the efficient combustion of such coal, the process must be constantly monitored; this mode of operation is implemented in the automatic boiler room Thermobot.

The principle of operation of a wood-pellet boiler

• Body type - the design provides for one or two combustion chambers.
• Reserve heat source - in some models, an electric heating element is provided, which heats the coolant when the combustion of the main type of fuel stops.
• The principle of gas generation or pyrolysis - a wood and pellet boiler burns fuel with limited air supply and high temperature. The creation of such conditions leads to increased production of gas, which is afterburned in a separate chamber, which increases the efficiency and thermal efficiency of the equipment.

Combined boiler for wood and pellets, demanding on the quality of fuel. For the pyrolysis process to begin, it is necessary that the moisture content of the fuel does not exceed 20%.

Double-fired boilers

• There is no need for re-equipment when switching to wood or pellets. The pellet burner is installed immediately. The design has a common heat exchanger, so the heating efficiency does not depend on the type of fuel used.
• Automatic switch to a backup fuel source. A two-burner combined heating boiler for pellets and wood usually works as follows. Firewood is used as the main source of heating. As soon as the logs burn out and the temperature of the coolant drops, the pellet burner automatically turns on, maintaining heating until the main type of fuel is used again.

Single-furnace boilers

The boilers are distinguished by the following characteristics:

• Less weight - compared to two-fired units, the weight of the boiler structure, even with a cast-iron heat exchanger, is significantly less.
• Difficulties associated with re-equipping the system - to convert the boiler to pellets, you need to install. The refurbishment, even with the condition of a certain experience, will take about 15 minutes. Automatic changeover from wood to pellets is not provided.
• Modest dimensions - boilers operating on wood pellets and wood have a lower height. Two-fired and single-fired units have a built-in pellet bunker for storing fuel. For boilers with one combustion chamber, the storage is often installed on top to save usable space.
• Automation - long-burning boilers are easier to control and prevent the coolant from overheating. Automation monitors air injection, supply and return water temperature. Some models have, among other things, a connection to room thermostats.

The efficiency of the boiler, operating on the principle of long burning, reaches 92%. Additional heat is produced by the combustion of gas generated during the gas generation process.

What is more profitable to use

It is best to start the comparison with the price of fuel, because we are worried about it the most. If we take average indicators, then 1 cubic meter of fuel briquettes costs about 2 times more than ordinary firewood. As we know, fuel briquettes can be made from different materials, but the price of firewood is highly dependent on the type of wood. If you choose the most expensive fuel briquettes and the cheapest timber, the cost may differ 3 times.

Note that most often there are products of two types of quality on the market. High-quality briquettes are denser without cracks and chips, often fired from the outside. Lower quality briquettes have a lower density, they are characterized by a multi-layer structure, which is slightly vulnerable to damage. Such briquettes burn faster and release less energy.

Popular fuel for stoves in homes and baths

Let's compare the indicators when working:

• How long fuel briquettes burn - usually 2 hours, while simple firewood is about an hour.
• The heat transfer from fuel briquettes is noticeably higher, since the fire in the stove is stable throughout the entire burning time. Firewood usually flares up quickly and gives off maximum heat immediately, and then gradually dies out.
• After using firewood, a lot of coals and ash appear in the firebox, while practically nothing remains from eurowood.

The main task is heating. They burn for a long time, emit a lot of heat, and at the same time do not take up much space in the house, do not litter, they are also environmentally friendly and safe to use as ordinary firewood. At the same time, they do not create a full-fledged atmosphere of comfort, do not crackle and often emit more unpleasant aroma when burning. No wonder their name contains the prefix "euro", this type of fuel was created primarily to save on heating.

If you use fuel briquettes for heating a house, then such a replacement of firewood for the stove is quite relevant, but for kindling a bath, such a choice will not always be justified. As well as for a fireplace, the task of which is not only to heat the house, but also to create the appropriate entourage, with which a substitute for firewood clearly cannot cope.

To evaluate the efficiency of fuel briquettes in each specific case, experiments should be carried out, too many factors affect their work. Only if you are convinced of the merits of this alternative fuel yourself, you can give it any assessment.

Recently, a lot of positive reviews have appeared on the network, indicating that it is more profitable to heat a house with Euro wood than conventional ones. We attribute this to the growing popularity of alternative fuels.

Fuel pellets

Our company offers pellets made from grade D coal originating from Kazakhstan. Almost any consumer is already aware of the peculiarities of application and distinctive characteristics of this coal, its popularity. But coal pellets and briquettes from it are in more and more demand only in recent years. And this is not surprising, because the consumption of such an energy carrier is only growing, and the pellets we offer not only retain all the positive properties of the source material, but also have their own attractive qualities:

• Ecological cleanliness
• No smoke, odor, sparking
• Carbon monoxide and other harmful compounds are not formed
• Low ash content and high carbon content
• High calorific value
• Long burning time
• Resistance to mechanical damage (not crushed during transportation, loading, storage)
• The same fraction, hence the uniformity of burning and dosage during use
• Convenience and compactness during storage, transportation and use
• Economy (less consumption with the same heat transfer)

Due to all of the above properties, fuel pellets made of coal, along with traditional coal, have begun to be used by an increasing number of consumers. Most often, our customers purchase pellets from coal (and brown) Kazakh coal in order to use this type of fuel for heating in solid fuel boilers, especially in boilers with automatic fuel supply, as well as in boiler houses and mini-boiler houses.

In addition to all of the above, our Company itself manufactures various briquetting and pellet equipment. Therefore, we can offer our partners and customers a wide variety of shapes and sizes of our own briquette products.

Qualitative characteristics of coal pellets (and briquettes) from Kazakh coal: Calorific value 5450-7044 kcal / kg Density up to 1.5 g / cm3 Ash content 8-10% Moisture 8-10% Sulfur content 0.3% Volatile 40-48%

Fuel pellets from coal are the most optimal raw materials for modern solid fuel boilers, both with manual combustion control and with automatic fuel supply.

Our fuel pellets from Kazakh coal of grade D burn much longer than pellets from biomass and, when burned, give much more heat, but at the same time, not as much heat as from anthracite, from which the walls of the boilers burn out.

Types and grades of coal

Coal is classified according to many parameters (geography of production, chemical composition), but from a “household” point of view, when buying coal for use in furnaces, it is enough to understand the labeling and the possibility of using it in Thermobot.

According to the degree of coalification, three types of coal are distinguished: brown, bituminous and anthracite. The following coal designation system is used: Grade = (grade) + (size class).

In addition to the main grades listed in the table, intermediate grades of coal are also distinguished: DG (long-flame gas), GZh (gas fatty), KZh (coke fat), PA (semi-anthracite), brown coals are also divided into groups.

Coking coal grades (G, coke, Zh, K, OS) are practically not used in heat power engineering, since they are a scarce raw material for the coke-chemical industry.