The most proven and effective way to heat a country house or cottage, in the absence of a gas pipeline, is to use solid fuel heating boilers. The method of using coal for space heating is considered, along with firewood, one of the most ancient and time-tested. Modern heating boilers, unlike a simple Russian stove, in which the room was heated by an open flame, use for this purpose the heat of heated water entering the radiators.
Therefore, any owner of a private house, before buying coal for heating, should be well aware of the main types of this natural material, as well as all the pros and cons of its use.
Features of the origin of coal
In the natural environment, dying plants undergo a process of decay, while in the future they become an excellent fertilizer for future plants. But under certain conditions, decomposition processes can be significantly slowed down and even completelypause. Therefore, the accumulation of rotting mass occurs much faster than natural decay. This is how peat is formed, which is the initial product of coal.
But to turn peat into coal, you need to create a huge pressure. Such pressure has been created in nature for many centuries, due to the movement of peat rocks deep into the earth with the help of alluvial soil. Over time, peat gets rid of gases and water and turns into brown coal.
The result of such a natural phenomenon is the formation of deep coal, as well as the purest coal - anthracite.
Basic properties of coal
The quality of coal for heating is characterized by almost twenty parameters. But all these characteristics are most often used by specialists. For a simple owner of a solid fuel stove or boiler, knowledge of the following basic characteristics of coal is sufficient:
- Heat released during combustion. This parameter indicates how much heat is released during the combustion of a certain mass of the product. So, brown coal, which is considered the lowest quality, with the complete combustion of one kilogram, releases 4500 kcal. But the calorific value of anthracite is 8600–8700 Kcal/kg. That is, the combustion of one kilogram of anthracite or coking coal emits almost twice as much heat as brown coal.
- The ash content of coal is characterized by the amount of impurities that remain after the complete combustion of a certain mass of material. Simply put, the less waste left whencombustion, the higher the quality of the product. For heating, an ash content of 25% is considered to be of high quality. Low-grade coal is considered to have an ash content of more than 40%.
- Coal moisture. The higher this indicator, the more heat will have to be spent on heating the coal and, as a result, less energy will be spent on heating the usable area.
Therefore, the decision on which coal is better for heating is made in accordance with the main characteristics, while all quality indicators in the complex must be taken into account.
Types of coal
Depending on the time of origin and depth of occurrence, coal for heating is divided into the following types:
- brown;
- stone;
- anthracite.
Also in this classification, an important indicator is the degree of coalification, that is, the percentage of carbon in natural material. The higher the proportion of carbon in the rock, the higher its combustion temperature, and hence the quality of the coal.
Brown coal
This natural material is a transitional link between peat and coal. The quality indicators of brown coal are very low. The high moisture content of the material (up to 40%) makes it difficult to obtain a high combustion temperature. The structure of the material is not dense, so after drying in the open air, coal can turn into powder. Carbon content is 50-77%.
Brown coal can be divided into several varieties:
- ordinary coal has dense pieces with a mattesurface, brown;
- earthy material has a loose structure, while it is very easy to grind into powder;
- tarry coal, dark brown in color, has a dense structure, with a shiny fracture surface;
- peat coal contains a lot of impurities.
Brown coal for home heating is used most often in small private boiler houses. Brown coal is marked with the letter B.
Coal
Deposits of coal for heating are found at a deeper level of the earth's surface. High pressure and temperature contributed to the improvement of the physical characteristics and chemical composition of this natural material. The carbon content of hard coal is in the range of 75-95%, which greatly increases its calorific value.
Depending on the quality indicators and scope of use, hard coal can be divided into the following types:
- gas (marking - G);
- fat (F);
- long-flame (D);
- coke (C);
- skinny (T).
The scope of coal is very diverse. Coal is especially widely used for heating boilers in a centralized system.
Anthracite
The highest quality fossil coal is anthracite. Compared to other types of coal products, it lies at the deepest depth and accounts for only three percent of the total coal reserves. Due to the high carbon content (about 95%), the combustion of anthracite occurs without a flame,with low smoke emission. The specific heat of combustion of this material reaches 8100–8350 kcal/kg, which is much higher than that of other types of coal, so anthracite is the best coal for heating.
The use of anthracite for domestic purposes is very limited due to its high cost, and the need to install special heat-resistant equipment. This coal is most widely used for heating in many industries. These are metallurgy, electrical and chemical industries.
Key features
Heating a house on coal is an ancient and highly efficient way. The main advantages of using coal for space heating are:
- When using coal, it is not necessary to install special pipelines for fuel supply.
- The process of heat release, when burning coal, does not stop even at the stage of its smoldering. That is why the heat in the room remains for a long time.
- High heat transfer of coal contributes to its use in small volumes.
- Easy transport and storage of fuel is also a big plus for any household.
- The affordable price of coal attracts many homeowners.
Features of furnace heating
Coal-fired heating stoves are structurally similar to wood-fired heating systems. But there are some features that you need to pay attention to:
- the furnace must have thickheat-resistant brick walls;
- the grate is installed of a reinforced type, since the combustion temperature of coal is much higher than firewood;
- to avoid heat loss, the size of the ash chamber and the grate must be equal;
- to increase traction, it is advisable to equip the oven with a special device.
If during the heating season the stove equipment is not used regularly, for example, in the country, then preparatory operations must be performed to heat the stove with coals:
- Inspect the oven for cracks. If there are even small defects, then they must be eliminated, since when heated, the cracks will increase, which can lead to a weakening of traction or the ingress of carbon monoxide into the room. You can cover the cracks with a mixture of sand and clay.
- It is also necessary to control the whitewashed pipe on the roof and attic.
- Clean the pipe once every six months.
- Before ignition, be sure to clean the firebox and ash chamber from combustion residues.
- Combustible items are recommended to be placed at least 1.5 m away from the oven.
Checking the draft in the stove chimney is easily checked with a lit paper. If the smoke from it goes into the chimney, then the draft is correct. Coal for home heating must be dry, so it must be stored in a specially equipped place.
Firing the stove
After carrying out the preparatory steps, you can proceed directly to the kindling of the furnace. Rememberthat it is strictly forbidden to use flammable liquids and materials to ignite heating oil.
Properly melt the oven in the following order:
- Sheets of crumpled dry paper or newspaper are placed on the bottom of the furnace compartment. Small chips of wood are laid on top. Next, small wooden logs are added, which are best folded in the form of a hut or well.
- After burning the paper, close the firebox door and open the blower.
- After the firewood has completely burned out, fine coal is placed on the smoldering residues, a layer 15 cm thick. To reduce coal sintering, it is better to mix this mass with a poker.
- When the fine fraction burns well, coarse coal is added to the furnace for heating.
- The furnace door closes, and with the help of the ash chamber damper, the necessary air flow is regulated for efficient combustion.
To increase the functionality of oven equipment, you can install special stoves for cooking.
Coal boiler operation principle
Coal-fired boilers are becoming increasingly popular for heating any premises, as they have a significant advantage - versatility. This means that such equipment can work effectively not only on coal, but also on firewood, sawdust, briquettes and many other types of solid fuels.
The principle of operation of a modern boiler differs significantly from other systems precisely in the way coal is burned. Unlike classic stoves, coal combustion occurs from top to bottom (likecandle), which ensures its most complete combustion, and increases the time of the technological process.
The combustion chamber of modern boilers is large, so one load of coal can smolder for quite a long time. Combustion air is supplied from above with the help of special fans.
Basic rules for storing coal
The quality of coal for heating largely depends on the conditions of its storage. Anthracite charcoal is the easiest to store, as pieces of 70–100 mm in size can be stored for up to three years, without any loss of quality.
The best place to preserve natural material is a covered shed or basement. At the same time, you need to make sure that the room is dry and does not get direct sunlight.
The process of coal oxidation can start at 20-25℃, and when the temperature rises to 40℃, weathering of the material can occur, which can be easily identified by the reduction in the size of the coal pieces.
It is also necessary to pay special attention to the fact that at high temperatures, all types of coal are capable of spontaneous combustion. To avoid this, it is recommended to cover a pile of coal with a thick tarpaulin. Watering coal is not recommended, as it, in this case, will oxidize faster.
Coal is a valuable natural material that is widely used for space heating. It can be used for heating both in furnaces and in special boilers.
