The combustion temperature of coal is considered the main criterion that allows you to avoid mistakes when choosing fuel. The performance of the boiler and its quality work directly depend on this value.

Temperature detection option

In winter, the issue of heating residential premises is especially relevant. Due to the systematic increase in the cost of coolants, people have to look for alternative options for generating thermal energy.

The best way to solve this problem is to select solid fuel boilers that have optimal performance characteristics and retain heat well.

The specific heat of combustion of coal is a physical quantity that shows how much heat can be released during the complete combustion of a kilogram of fuel. In order for the boiler to operate for a long time, it is important to select the correct fuel for it. The specific heat of combustion of coal is high (22 MJ/kg), so this type of fuel is considered optimal for efficient boiler operation.

Characteristics and properties of wood

Currently, there is a tendency to switch from installations based on the gas combustion process to solid fuel heating household systems.

Not everyone knows that creating a comfortable microclimate in the house directly depends on the quality of the chosen fuel. Let us highlight wood as a traditional material used in such heating boilers.

In harsh climatic conditions, characterized by long and cold winters, it is quite difficult to heat a home with wood for the entire heating season. When the air temperature drops sharply, the owner of the boiler is forced to use it to the brink of its maximum capabilities.

When choosing wood as a solid fuel, serious problems and inconveniences arise. First of all, we note that the combustion temperature of coal is much higher than that of wood. Among the disadvantages is the high rate of combustion of firewood, which creates serious difficulties when operating the heating boiler. Its owner is forced to constantly monitor the availability of firewood in the firebox; a fairly large amount of it will be required for the heating season.

Coal options

The combustion temperature is much higher, so this fuel option is an excellent alternative to conventional firewood. We also note the excellent heat transfer rate, the duration of the combustion process, and low fuel consumption. There are several types of coal, related to the specifics of mining, as well as the depth of occurrence in the bowels of the earth: hard, brown, anthracite.

Each of these options has its own distinctive qualities and characteristics that allow it to be used in solid fuel boilers. The combustion temperature of coal in a furnace will be minimal when using brown coal, since it contains a fairly large amount of various impurities. As for heat transfer indicators, their value is similar to wood. The chemical combustion reaction is exothermic, the calorific value of coal is high.

Coal has an ignition temperature of 400 degrees. Moreover, the calorific value of this type of coal is quite high, so this type of fuel is widely used for heating residential premises.

Anthracite has maximum efficiency. Among the disadvantages of such fuel, we highlight its high cost. The combustion temperature of this type of coal reaches 2250 degrees. No solid fuel extracted from the bowels of the earth has such an indicator.

Features of a coal-fired furnace

Such a device has design features that involve the pyrolysis of coal. does not belong to minerals, it has become a product of human activity.

The combustion temperature of coal is 900 degrees, which is accompanied by the release of a sufficient amount of thermal energy. What is the technology to create such an amazing product? The essence lies in a certain processing of wood, due to which a significant change in its structure occurs and excess moisture is released from it. A similar process is carried out in special ovens. The operating principle of such devices is based on the pyrolysis process. A charcoal furnace consists of four basic components:

• combustion chambers;
• reinforced foundation;
• chimney;
• recycling compartment.

Chemical process

After entering the chamber, gradual smoldering of the firewood occurs. This process occurs due to the presence in the firebox of a sufficient amount of oxygen gas that supports combustion. As the smoldering process occurs, a sufficient amount of heat is released and excess liquid is converted into steam.

The smoke released during the reaction goes to the secondary processing compartment, where it burns completely and heat is released. performs several important functional tasks. With its help, charcoal is formed, and a comfortable temperature is maintained in the room.

But the process of obtaining such fuel is quite delicate, and with the slightest delay, complete combustion of the wood is possible. It is necessary to remove charred pieces from the oven at a certain time.

Application of charcoal

If the technological chain is followed, an excellent material is obtained that can be used for full heating of residential premises during the winter heating season. Of course, the combustion temperature of coal will be higher, but such fuel is not affordable in all regions.

Charcoal combustion begins at a temperature of 1250 degrees. For example, a smelting furnace runs on charcoal. The flame that is formed when air is supplied to the furnace easily melts the metal.

Creating optimal conditions for combustion

Due to the high temperature, all internal elements of the furnace are made of special refractory bricks. Fireproof clay is used for their installation. If special conditions are created, it is quite possible to obtain a temperature in the furnace exceeding 2000 degrees. Each type of coal has its own flash point. After reaching this indicator, it is important to maintain the ignition temperature by continuously supplying excess oxygen to the firebox.

Among the disadvantages of this process, we highlight heat loss, because part of the released energy will escape through the pipe. This leads to a decrease in the temperature of the firebox. In the course of experimental studies, scientists were able to establish the optimal excess amount of oxygen for various types of fuel. Thanks to the choice of excess air, you can count on complete combustion of the fuel. As a result, you can count on minimal losses of thermal energy.

Conclusion

The comparative value of a fuel is assessed by its calorific value, measured in calories. Taking into account the characteristics of its different types, we can conclude that hard coal is the optimal type of solid. Many owners of their own heating systems try to use boilers that run on mixed fuel: solid, liquid, gaseous.

The quality of coal will determine the amount of energy we can get, the time for maintenance, and in general the ability to burn with it... Which coal is better for home heating? and how to burn it correctly in order to achieve maximum energy output and minimum worries.

Coal combustion temperature and other characteristics

People often ask, “What is the combustion temperature of coal?”, although this value has little effect. Other parameters are much more important.

• calorific value – the amount of heat generated per kilogram of fuel, kW/kg;
• ash content - the amount of ash that remains after burning coal, % of the total mass. It will reduce the overall calorific value, we will have to clean it from the boiler and dispose of it,

Also important:

• Caking is the ability of coals to create caked ash, which is very harmful.
• Humidity, both in-situ and introduced—isn’t it wet coal? It is better to dry wet water first under natural conditions than to burn it in a boiler with the loss of energy that will be spent on evaporation of this water.
• Volatile release, tendency to coking - coking coal grades are not suitable for heating.

More details about ash content

The ash content is as follows.

• In-situ - these are those mineral impurities, “sand and stones”, that are located inside the coal seam, in every piece of coal, and they cannot be extracted during enrichment. Good coals have up to 10% ash.
• Technical is rock that was mixed with coal during its extraction, including from large rock layers inside the coal seam, and which can be separated from coal by mechanical methods during its enrichment. The miners accidentally cut down the roof and soil of the seam - that’s extra tons, even though the ash content is high... The rock mass from the mine can have 35% ash content - it’s not at all suitable for home combustion.

It must be borne in mind that adding rock significantly increases the volume of pockets for those selling coal. Therefore, buying coal is not an easy task. It is necessary to check the fuel for the presence of pieces of rock, including those sprinkled, directly in the carriage, in the car, before unloading. And refuse to purchase, if anything...

What is the calorific value of different grades of coal?

How much heat can we get from coal, is it enough to heat the house?

The amount of heat in kilowatts that can be released from different brands of coal compared to dry firewood is given below, kW/kg

• Dry firewood – 4.0
• Brown coals – 3.8 – 5.5
• Long flame – 6.0 -7.0
• Gas and fat – 7.5
• Lean-sintering 7.0 – 7.4
• Lean – 7.4 – 8.0
• Anthracite – 7.8 – 9.5

The most suitable thermal coal grades for home boilers are lean, anthracite and semi-anthracite. They are the ones who sinter less and form coke substances, have a minimum of ash inside the formation and better calorific value .

In addition to the brand, you need to choose a coal size class.

Coal size class, why they don’t burn coal dust

Coal dust and coal pellets are the cheapest and burn well, but only in special furnaces at power plants. There they burn in a cloud with fuel oil and air. And in a boiler, they simply seal the passage of air through them, so combustion inside their layer is impossible. A piece of coal does not burn in stoves, except with small additions, poured on top of the burning coal.

• You can heat it with sunflower seeds, but as a rule, it spills through the grates of all boilers...
• For home heating, more expensive fractions are used - nut and fist.
• Slab coal is even more expensive, but at home it is broken into smaller pieces.

There are many unburnt elements left in coal ash. After burning, the zealous owners sift the ash on a 5 mm metal grid, and all the large unburned parts are sent back to the boiler along with a fresh portion. This saves 10–15% of fuel.

They try to moisten coal dust into cakes, which are dried and fed into the boiler in the form of pellets.

How to burn coal correctly

If oxygen is not added to the combustion zone, then instead of carbon dioxide, carbon monoxide is formed - CO, the efficiency from incomplete combustion decreases by 20 - 50%. Modern boilers provide secondary air for afterburning CO and soot particles at high temperatures. With old equipment, with stoves, you need practical skill in supplying air over burning coals for better afterburning and preventing the release of unburned gases into the atmosphere.

Supplying a large amount of primary air directly into burning coal can turn the boiler into a forge, lead to rapid combustion of a large mass of coal, a sharp increase in the temperature of the exhaust gases up to 1500 degrees and melting of the equipment, ignition of soot in the chimney, a sharp drop in efficiency several times, from -for the removal of energy into the pipe.

The efficiency of coal combustion can be monitored by the temperature of the exhaust gases, which should not increase. There should be enough air so that complete combustion of the fuel occurs without CO and at the same time there is no increase in temperature in the chimney above normal. As a rule, modern coal boilers are able to burn fuel as required with a maximum efficiency of about 78%.

How to make coal burn for a long time

Normal long-term combustion with high efficiency is achieved better with modern equipment. But even on old boilers and furnaces, you can find the optimal approximate opening of the lower and upper dampers to ensure a normal air supply over the fuel for afterburning CO on the heat exchanger.

For example, a regular old coal stove provided the following adjustments:

• "the vent is closed"
• “the two upper burners are slightly open”,

- a portion of coal smolders - long-term combustion occurs, but the afterburning of gases is usually complete.

In modern boilers, such modes are monitored by the equipment itself.

High-power coal boilers (large load possible) from well-known manufacturers with secondary air supply are suitable as a cheap and universal option for home heating. They can be used to burn a large load of coal for a long time by redistributing the air supply.

Automated boilers are becoming more and more popular now. Their combustion duration is ensured by a coal bunker and a constant supply of small portions to the combustion zone. Moreover, the equipment is not necessarily too expensive. Boilers with a bunker from which fuel is loaded under its own weight have an affordable price. Boilers with screw feed are more expensive, but they can do a little more. Thus, the bunker allows you not to worry about adding fuel every day. Combustion occurs, as a rule, in small portions, but with a full supply of air without the formation of large volumes of CO - European environmental requirements for equipment.

In any case, the increased burning time of coal will be ensured primarily by equipment for large loads - in a bunker or directly in the furnace. The choice of a boiler for coal is based on this consideration.

Which coal to choose

Coal occurs in the earth's crust in the form of layers. Each of them is labeled and has its own quality characteristics. But even in the same seam, but in different areas, coal can vary greatly in quality - the degree of metamorphism, the amount of ash, volatiles, sulfur, humidity change...

For energy purposes, the most valuable coals are those with the highest degree of metamorphism, with the highest percentage of carbon C in the composition. These are Anthracites and those close to them, which are assigned the brands Semi-Anthracites and Lean Coals.

The best coals for heating will be anthracite and semi-anthracite from the processing plant, walnut and fist fractions.

By region of production, the best thermal coals were previously mined in the Donbass, but recently production has been greatly reduced, and such coals are difficult to find on the market. In any case, the anthracites of the Donbass layers H2 Removsky, N2-1 Podremovsky, N-8 Fominsk were considered the best for home heating. There is a known record for the calorific value of a kilogram of coal mined in the 70s from the Fominskaya seam with a value of 9800 kW/h.

Now it is cheaper to purchase coal from Kuzbass and Ekibastuz, despite the long delivery. You need to ask for coals from the energy layers of Kuzbass.

The purchased coal must contain a minimum amount of:

• tufts, dust, which practically do not burn and have a bad effect on the combustion process, filling the boiler, limiting the access of oxygen to large pieces;
• rocks - pieces of rock in coal - this is a waste of enrichment or a special mixture at different stages of trade.

It is better to immediately warn the seller that you will refuse to purchase coal with a piece and rock. Order walnut and fist coal fractions in small portions to check; as a rule, the seller has a supply for the whole season, and you can buy additional fuel if it is of good quality.

The theoretical combustion temperature of coal lies in the range of 1000...2300 °C and depends on a number of factors - combustion conditions, specific calorific value, moisture content, and so on. The actual heating at the center of the flame burning in the firebox of a boiler or stove rarely exceeds 1200 degrees. But the owner of the home is not at all faced with the task of heating the unit and pipes white-hot. The main goal is to efficiently use the energy of a valuable fossil, obtaining the required amount of heat over a long period.

Types of coals used for heating

The formation of black fuel in the depths takes from several hundred thousand to millions of years. The deeper and older the deposit, the higher the density and heat of combustion of the coal mass. The energy value of a fuel depends on one indicator - the percentage of pure carbon in the fossil composition.

Let us list the types of coals burned in heating stoves, in order of increasing calorie content:

1. Brown coal contains up to 70% carbon. The remaining 30% are volatile substances (bound oxygen, nitrogen, hydrogen) and impurities - sulfur, iron, phosphorus, silicon and aluminum.
2. Denser coal is 82% carbon, the rest is impurities and moisture.
3. Anthracite is the oldest fuel, containing up to 95% carbon.

Reference. The first and last link is missing in this chain. First, biomass - plants and trees - forms low-calorie peat, which lies close to the surface and is suitable for briquette production. The chain is completed by natural graphite, consisting of the purest carbon.

Coal solid fuel is divided into types and classes according to physical properties and fraction sizes. Depending on the origin, the composition of coal changes, which affects its characteristics - ignition and combustion temperature, calorific value and ash content. The table below shows the classification of hard coals according to the content of volatile substances, moisture and ash.

After mining, the coal mixture undergoes calibration - division into fractions. The larger the pieces, the higher the price of the energy carrier and the better the combustion occurs. We will show in the next table how different they are and how coals of different sizes are designated.

Note. If, in addition to the fuel grade, it is necessary to indicate the fraction size, the letter index is assigned to the main class designation. Example: GO – gas nut, AP – anthracite – stove. The marking of a brown mixture of nuts and fines is BOM.

We do not include charcoal in the general classification for several reasons:

• fuel is not a fossil, it is a product of dry processing (distillation) of wood;
• the use of burnt coal for heating a home is not economically profitable, it is cheaper to buy;
• This fuel is well suited for operating a forge, a gas generator, or burning in a barbecue.

Ignition temperature and other parameters

The process of coal combustion is a chemical reaction of carbon oxidation that occurs at a high initial temperature with intense heat release. Now it’s simpler: coal fuel cannot ignite like paper; ignition requires preheating to 370-700 ° C, depending on the type of fuel.

Key moment. The efficiency of coal combustion in a stove or household solid fuel boiler is characterized not by the maximum temperature, but by the completeness of combustion. Each carbon molecule combines with two oxygen particles in the air to form carbon dioxide CO2. The process is reflected in the chemical formula.

If you limit the amount of incoming oxygen (cover the ashpit, switch the TT boiler to smoldering mode), instead of CO2, flammable carbon dioxide CO is formed, which is emitted into the chimney, and the combustion efficiency will significantly decrease. To achieve high efficiency, you need to provide favorable conditions:

1. Brown coals ignite at a temperature of +370 °C, hard coals - 470 °C, anthracite - 700 degrees. Pre-heating of the heating unit using firewood (sawdust briquettes) is required.
2. Air is supplied to the firebox in excess, the safety factor is 1.3-1.5.
3. Combustion is maintained by the high temperature of the hot layer of coals lying on the grate. It is important to ensure the passage of oxygen through the entire thickness of the fuel, since air moves through the ash pan due to natural chimney draft.

Comment. The exception is homemade and cylindrical top-combustion boilers, where air is supplied to the firebox from top to bottom.

The theoretical combustion temperature and specific heat transfer of various types of fuel are shown in the comparison table. It is noticeable that under ideal conditions any fuel will release maximum heat when interacting with the required volume of air.

In practice, it is unrealistic to create such conditions, so air is supplied with some excess. The actual combustion temperature of brown coals in a conventional TT boiler lies in the range of 700...800 °C, of ​​rocks and anthracites - 800...1100 degrees.

If you overdo it with the amount of oxygen, energy will begin to be spent on heating the air and simply fly out into the chimney, the efficiency of the furnace will noticeably drop. Moreover, the fire temperature can reach 1500 °C. The process resembles an ordinary fire - the flame is large, there is little heat. An example of efficient combustion of coal with a retort burner on an automatic boiler is presented in the video:

Complete combustion of coal fuel requires a special approach to the issue. The task is to achieve maximum efficiency of the heat source, not to overheat the coolant and not start a fire due to too high a temperature.

You need to get used to each type of coal. It is better to add unfamiliar fuel in small portions, adjusting the draft with a damper and watching the temperature rise. When you have calculated all the combustion nuances of a given brand, fill the firebox 2/3 full.

The primary criterion for not making a mistake in choosing a fuel and heating device is the combustion temperature of coal, since its value determines the good operation of the boiler and its productivity.

The issue of heating your own home in winter is especially acute. With energy prices constantly rising, people are forced to look for alternative ways to generate heat. The best solution in this situation is to use solid fuel boilers that have optimal heat production and retention characteristics.

But for their full operation, the preparation of solid fuel is necessary. Its best variety is coal, which ensures optimal stove performance. The correct choice of this fuel is the key to efficient operation of the boiler.

Solid fuel boilers are replacing installations based on the principle of gas combustion. Some have been using them for quite a long time, others are just starting to use them to heat their own homes. But everyone knows that the creation of comfortable conditions in the home fully depends on the quality of the fuel. The traditional material used in such devices is wood. It is the one that is most widely used. However, it is quite difficult to heat a home using this material throughout the winter. This becomes especially clear during periods of extreme frost, when the boiler operates almost at its maximum capacity.

However, the use of firewood is associated with some inconveniences. First of all, it is a fairly low temperature and rapid combustion. During the combustion of wood, the temperature rises to only 200-400°C, while heat transfer rates reach significant values. But due to the rate of combustion, this type of fuel creates certain difficulties, requiring constant monitoring of the presence in the firebox. This fact is the most significant disadvantage, since it requires a huge supply of firewood for the winter.

An alternative to wood is coal. This type of fuel has improved heat transfer and combustion time, which ensures lower consumption. It has varieties depending on the depth of its occurrence in the subsoil and the characteristics of the extraction of raw materials. They look like this:

Each of the above options has its own qualities and characteristics that allow them to be used in solid fuel boilers. Heating with brown coal is the least efficient compared to other types of similar fuel. This is due to its structure containing many impurities. Its combustion temperature is about 230-250°C. At the same time, heat transfer rates do not differ much from wood values. During the combustion of brown coal, a temperature of about 1900°C is ensured. However, such indicators are maximum, and the actual values ​​​​obtained during the use of fuel are much lower.

Hard coal ignites at 400°C, producing much more heat than brown coal. The combustion temperature of coal in a furnace is about 2100°C. This ensures its long-term use and high heat transfer. This type of mineral is mainly used for heating buildings.

Anthracite is the most effective, but also disproportionately expensive option. Its combustion temperature ranges from 500-600°C and reaches values ​​of 2250°C. None of the types of solid fuel extracted from the bowels of the earth can boast of such indicators.

Design characteristics of a charcoal kiln based on the use of pyrolysis

Charcoal should be considered a separate category. This type of fuel is not a fossil fuel. It rather represents the flow of progress, since it is entirely produced by man. A low temperature of 100-200°C is sufficient to ignite it. Moreover, during the combustion of charcoal it reaches about 800-900°C, which provides excellent heat release qualities. How is this wonderful product produced? This process is quite simple. It consists in special processing of wood, which allows you to significantly modify its structure by releasing moisture from it. To accomplish this difficult task, charcoal kilns are used. As their name implies, the purpose of these devices is to perform wood processing functions. Furnaces for the production of charcoal have a certain structure and similar design elements.

The operating principle of such a device is based on the influence of the pyrolysis process on wood, which performs the function of transforming it. The charcoal pyrolysis furnace consists of 4 main components:

• reinforced base;
• the combustion chamber;
• recycling compartment;
• chimney.

Drawings of this device make it possible to trace exactly what processes are occurring inside the structure. Once in the combustion chamber, the firewood begins to gradually decay. This process is caused by the lack of oxygen in the firebox, which is necessary to maintain a full fire. During the smoldering process, a sufficient amount of heat is released, and the liquid contained in the wood evaporates. The smoke released as a result of a similar effect enters the secondary processing compartment, where it is completely burned, generating heat.

Thus, the charcoal kiln performs several tasks at once. The first of them allows you to create charcoal, the second provides the room with a sufficient amount of heat. However, the process of converting firewood is extremely delicate, since the slightest delay can lead to complete combustion. Therefore, at a certain point, the charred workpieces must be removed from the oven.

As a result of this process, we will be able to obtain excellent material that will help to fully heat the room in winter. Charcoal kilns play an important role in this case, since charcoal practically does not occur in nature.

Content

The efficiency and economy of a heating system with a solid fuel boiler directly depends on the type of fuel. In addition to firewood and wood waste, various types of coal are actively used as an energy source. The combustion temperature of coal is one of the important indicators, but should it be taken into account when choosing fuel for a stove or boiler?

Coal in the furnace

Coal: varieties and characteristics

Coals primarily differ in origin. Charcoal, which is obtained by burning wood, as well as fossil fuels are used as an energy source.

Fossil coals are fuels created by nature. They consist of the remains of ancient plants and bitumen masses, which underwent a number of transformations in the process of sinking underground to great depths. The transformation of starting substances into effective fuel took place at high temperatures and in conditions of oxygen deficiency under the earth. Fossil fuels include brown and hard coals, as well as anthracite.

Brown coals

Among fossil coals, the youngest are brown coals. The fuel got its name from its brown color. This type of fuel is characterized by a large amount of volatile impurities and high moisture content - up to 40%. In this case, the amount of pure carbon can reach 70%.

Due to high humidity, brown coal has a low combustion temperature and low heat transfer. Fuel ignites at 250°C, and the combustion temperature of brown coal reaches 1900°C. The calorific value is approximately 3600 kcal/kg.

As an energy carrier, brown coal in its natural form is inferior to firewood, so it is rarely used for stoves and solid fuel units in private homes. But briquetted fuel is in steady demand.

Brown coal in briquettes is a fuel that has undergone special preparation. By reducing humidity, its energy efficiency increases. The heat transfer of briquetted fuel reaches 5000 kcal/kg.

Stone coals

Hard coals are older than brown coals; their deposits are located at a depth of up to 3 km. In this type of fuel, the content of pure carbon can reach 95%, and volatile impurities - up to 30%. This energy carrier contains no more than 12% moisture, which has a positive effect on the thermal efficiency of the mineral.

The combustion temperature of coal under ideal conditions reaches 2100°C, but in a heating furnace the fuel is burned at a maximum of 1000°C. The heat transfer of coal fuel is 7000 kcal/kg. It is more difficult to ignite - it requires heating up to 400°C to ignite.

Coal energy is most often used to heat residential buildings and other buildings.

Anthracite

The oldest solid fossil fuel, which contains practically no moisture and volatile impurities. The carbon content in anthracite exceeds 95%.

The specific heat transfer of the fuel reaches 8500 kcal/kg - this is the highest indicator among coals. Under ideal conditions, anthracite burns at 2250°C. It ignites at a temperature of at least 600°C - this is an indicator for the lowest calorie types. Ignition requires the use of wood to create the necessary heat.

Anthracite is primarily an industrial fuel. Its use in a furnace or boiler is irrational and expensive. In addition to high heat transfer, the advantages of anthracite include low ash content and low smoke.

Properties of charcoal

Charcoal is placed in a separate category because it is not a fossil fuel, but a manufactured product. To obtain it, wood is processed in a special way to change the structure and remove excess moisture. The technology for producing an effective and easy-to-use energy carrier has been known since ancient times - previously, wood was burned in deep pits, blocking access to oxygen, and today special charcoal kilns are used.

Under normal storage conditions, the moisture content of charcoal is about 15%. The fuel ignites when heated to 200°C. The specific calorific value of the energy carrier is high - it reaches 7400 kcal/kg.

The burning temperature of charcoal varies depending on the type of wood and combustion conditions. For example, birch coals can be used to heat a forge and forge metal - with an intensive air supply they will burn at 1200-1300°C. In a stove or heating boiler, the temperature during combustion will reach 800-900°C, and when using coal in a barbecue outside - 700°C.

Fuel from burnt wood is economical - its consumption is significantly lower compared to using firewood. In addition to high heat transfer, it is characterized by low ash content.

Due to the fact that charcoal burns with a small amount of ash and produces even heat without an open flame, it is ideal for cooking meat and other foods over an open fire. It can also be used for fireplace heating or cooking on a stove.

Features of coal combustion

When considering at what temperature a particular type of fuel burns, it should be borne in mind that the figures given are achievable only under ideal conditions. It is impossible to create such conditions in a home stove or solid fuel boiler, and it is not necessary. A brick or metal heat generator is not designed for this level of heating, and the coolant in the circuit will quickly boil.

Therefore, the combustion temperature of the fuel is determined by its combustion mode, that is, by the amount of air supplied to the combustion chamber. Fossil and wood fuels burn best when the air supply reaches 100%. A valve or damper is used to limit the air flow, thereby maintaining the fuel combustion temperature that is optimal for the furnace - about 800-900°C.

When burning energy in a boiler, you must not allow the coolant to boil in the water jacket - if the safety valve does not work, an explosion will occur. In addition, the mixture of steam and water has a detrimental effect on the circulation pump in the heating system.

To control the combustion process, the following methods are used:

• the energy carrier is loaded into the firebox and the air supply is regulated;
• coal chips or fuel pieces are supplied in doses (according to the same scheme as in pellet boilers).

Combustion Features

Coals vary in type of flame. Burning hard and brown coal have long flames, anthracite and charcoal are short-flame energy carriers. Short-flame fuel burns with virtually no residue, releasing a large amount of thermal energy.

The combustion of long-flame energy carriers occurs in two stages. First of all, volatile fractions are released - combustible gas, which burns, rising to the top of the combustion chamber. In the process of releasing gases, the coal cokes, and after the volatile substances burn out, the resulting coke begins to burn, forming a short flame. The carbon burns out, leaving slag and ash behind.

Conclusion

When choosing which energy carrier is best to use for a solid fuel boiler or stove, you should pay attention to fossil fuels and charcoal. The combustion temperature is not important, since in any case it will have to be limited in order to maintain the optimal operating mode of the heat generator.

It is important to evaluate the availability of energy and its cost, thermal efficiency, and ease of use. For boiler units, stone or brown coal is most often used. Combustion of hard coal in a pyrolysis furnace is the best option, which allows you to use maximum thermal energy, reducing fuel consumption and reducing the amount of harmful emissions.

The furnace or boiler unit must be designed to work with high-temperature energy carriers.