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 hot 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 significantly slow down and even completely stop. Therefore, the accumulation of rotting mass occurs much faster than natural decay. It is in this way that peat is formed, which is the initial product of coal.
But to turn peat into coal, tremendous pressure must be created. Such pressure has been created in natural nature for many centuries, due to the movement of peat rocks inland with the help of alluvial soil. Over time, peat gets rid of gases and water and turns into brown coal.
The result of this natural phenomenon is the formation at a great depth of coal, as well as the purest coal - anthracite.
The main 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 the simple owner of a solid fuel furnace or boiler, knowledge of the following basic characteristics of coal is sufficient:
- The heat released during combustion. This parameter indicates how much heat is generated when a certain mass of product is burned. So, brown coal, which is considered the most low-quality, with the complete combustion of one kilogram emits 4,500 Kcal. But the rate of calorific value of anthracite is 8600–8700 Kcal / kg. That is, the combustion of one kilogram of anthracite or coking coal produces almost twice as much heat as brown coal.
- The ash content of coal is characterized by the amount of impurities that remain after complete combustion of a certain mass of material. Simply put, the less waste remains during combustion, the higher the quality of the product. For heating, an ash content of 25% is considered high-quality. Low-grade coal is considered to have an ash content of more than 40%.
- Humidity of coal. 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 solution to the question of which coal is better for heating is taken 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, coal for heating is divided into the following types:
Also in this classification, an important indicator is the degree of coalification, that is, the percentage of carbon in the natural material. The higher the proportion of carbon in the rock, the higher its combustion temperature, and consequently, the quality of coal.
Brown coal
This natural material is a transitional link between peat bog and coal. Quality indicators of brown coal are very low. High humidity 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 contains 50–77%.
Brown coal can be divided into several varieties:
- ordinary coal has dense pieces with a matte surface, brown;
- the earthy material has a loose structure, and it is very easy to grind into powder;
- resinous coal, dark brown in color, has a dense structure, with a shiny fracture surface;
- peat coal includes a lot of impurities.
Brown coal for home heating is most often used in small private boiler rooms. Brown coal is marked with the letter B.
Coal
Coal deposits 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 in hard coal is in the range of 75–95%, which greatly increases its calorific value.
Depending on the quality indicators and the scope of use, coal can be divided into the following types:
- gas (marking - G);
- fatty (F);
- long flame (D);
- coke (K);
- 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 with 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 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 needs 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. It is metallurgy, electrical and chemical industries.
Main advantages
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 mount special pipelines for supplying fuel.
- The process of heat generation during coal combustion does not stop even at the stage of its decay. That is why the heat in the room is stored for a long time.
- High heat transfer of coal contributes to its use in small volumes.
- Easy transportation and storage of fuel is also a big plus for any household.
- The affordable price of coal attracts many owners of private homes.
Features of stove heating
Coal heating furnaces are structurally similar to a wood fuel heating system. But there are some features that you need to pay attention to:
- the firebox should have thick walls made of heat-resistant bricks;
- the grate is installed 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 should be equal;
- To enhance traction, it is advisable to equip the furnace with a special device.
If during the heating season the furnace equipment is not used regularly, for example, in the country, then preparatory operations are necessary to heat the furnace with coals:
- Inspect the furnace for cracks. If even small defects exist, then they must be eliminated, since when heated, the cracks will increase, which can lead to weakening of traction or carbon monoxide entering 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.
- Once every six months, clean the pipe.
- Before ignition, it is necessary to clean the combustion chamber and the ash chamber from burning residues.
- Combustible items are recommended to be located at a distance of at least 1.5 m from the furnace.
Checking the draft in the chimney can be easily checked with lighted paper. If the smoke from it goes into the chimney, then the draft is correct. Coal for heating the house must be dry, therefore it must be stored in a specially equipped place.
Kindling furnace
After carrying out the preparatory steps, you can proceed directly to the kindling of the furnace. Remember that for the ignition of heating oil, it is strictly forbidden to use flammable liquids and materials.
Correctly melt the furnace in the following order:
- Sheets of crumpled dry paper or newspaper lie on the bottom of the furnace compartment. Small pieces of wood are stacked on top. Next, small wooden logs are added, which are best folded in the form of a hut or a well.
- After burning the paper, the furnace door must be closed, and the blower must be opened.
- After the wood has completely burned, fine coal is laid on smoldering residues, with a layer 15 cm thick. To reduce sintering of coal, 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 the furnace equipment, you can install special stoves for cooking.
The principle of operation of a coal boiler
Coal fired boilers are becoming increasingly popular for heating any room, as they have a significant advantage - versatility. This means that such equipment can work effectively not only on coal, but also on wood, sawdust, briquettes and many other types of solid fuel.
The principle of operation of a modern boiler differs significantly from other systems precisely in the way it burns coal. Unlike classical furnaces, coal burns from top to bottom (like a candle), which ensures its most complete combustion, and increases the process time.
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 using special fans.
Basic rules for storing coal
The quality of coal for heating largely depends on its storage conditions. It is easiest to preserve anthracite coal, so pieces of 70-100 mm in size can last up to three years, while there is no loss of quality.
The best place to preserve natural material is an indoor barn or basement. At the same time, you need to ensure that the room is dry, and direct sunlight does not fall there.
The process of coal oxidation can begin at 20–25 ℃, and when the temperature rises to 40 ℃, weathering of the material can occur, which can be easily determined by reducing the size of pieces of coal.
It is also necessary to pay special attention to the fact that at high temperatures all types of coal are able to ignite spontaneously. To avoid this, a heap of coal is recommended to be covered with a dense tarpaulin. Watering coal is not recommended, since 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.