Coal: composition, application, extraction methods

2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16

This rock, which is formed in the thickness of the earth's crust, is very diverse. To date, its varieties are distinguished, such as, for example, brown coal, anthracite, coal. The composition of coal is moisture and mineral impurities. However, with regard to moisture, it significantly reduces the heat of combustion.

The composition of the breed. Chemicals

Besides the fact that coal contains moisture, it also contains a substance such as sulfur. This impurity is also considered harmful, and it is not contained in its pure form, but in the composition of impurities such as pyrite, calcium, iron sulfate. When coal is used, or rather, when it is burned with such impurities in the composition, harmful evaporation will form - sulfur dioxide, or sulfur dioxide. It has a rather negative effect on human he alth if it is breathed. It is capable of causing rapid corrosion of the metal, as well as poisoning the atmosphere with its fumes. It should be noted that the sulfur content in the composition of coal, which is mined in the Donets Basin, is quite low. The indicator of this substance is only 1-2%. If compared with the basins of the central and northern regions, then the content of this harmful impurity in them only starts from 3.5%. Fullthe chemical composition of raw materials is as follows:

• highest percentage of carbon - from 50 to 96%;
• after carbon comes oxygen, the content of which is from 25 to 37%;
• the third in this list is hydrogen, its percentage is from 3 to 6%;
• The last chemical is nitrogen, its content can be from 0 to 2.7%.

Peat

Today, peat is also used, which is the remains of rock. It is used quite widely, despite the fact that it is considered, in fact, a waste. It is worth noting here that the composition of this type of coal differs in that the quantitative content of all harmful impurities, including sulfur, is much less. The percentage of the chemical element carbon also dropped to 50-60%.

Brown coal

By itself, brown coal is an earthy mass with a fairly high density, which is formed from peat, but at the same time perfectly retains its woody structure. The use of this type of coal is much less common than stone, for example. This is due to the fact that when burned, it creates a smoky flame, which also creates a rather unpleasant odor. It is most often used in dry distillation. With its help, it is possible to obtain substances such as, for example, ammonia with acetic acid. This breed is considered the youngest of all other varieties. The composition of this type of coal is as follows:

• as inthe previous type, carbon prevails here - 50-77%;
• oxygen content is practically the same - 26-37%;
• percentage of hydrogen is 3-5, and nitrogen is 0-2.

It is worth adding that the strong development of technology has led to the fact that technologists have learned how to obtain synthetic gas from this raw material, which can be used as an alternative to fuel oil.

Coal

This fossil material is a transitional material from lignite to anthracite. It differs in that it is an excellent fuel, unlike brown matter. It is this breed that is the most mined in our time. It is most widely used as a fuel for thermal power plants, for example. It is excellent for heating private houses, for the operation of factories, etc. The calorific value that this type of raw material has is much higher than that of brown. As harmful impurities, this type of coal contains moisture in an amount of 3 to 12%. In addition, it also contains 32% volatile burning substances.

The chemical composition is different from the previous species. The amount of carbon is much higher - from 75 to 93%. The oxygen content decreased significantly - 3-19%, the hydrogen content remained approximately at the same level - 4-6%. The nitrogen indicator is still low - up to 2.7%.

If you ask the question, which coal is better, then the answer to it, most likely, will be the following: anthracite. It differs in that its structure is as dense as possible, the surface is a little shiny, and the calorific value has the best indicator. Its only drawback is that it lights up quite badly. Most often it is used to make things like carbon electrodes, electrode paste. Its use as a fuel raw material in the metallurgy industry is very common. The depth of occurrence of this rock is quite large - 6 km. Of the chemicals, it contains carbon in an amount of 95-97%, as well as hydrogen - from 1 to 3%.

Method of mining

It is worth noting that the method of extraction is very dependent on the location of the coal deposit, or rather, on the depth of its occurrence. Depending on this factor, an open (quarry) method and a mine, closed method are distinguished. Each method is distinguished by its technology, as well as advantages and disadvantages.

Open Mining

The main advantage of open pit coal mining is relative safety. The thing is that it is used only if the depth of the rock is not more than 100 meters. In other words, no shaft is created that can collapse during an accident. The mining process itself is carried out according to the following procedure.

First you need to remove the top layer of soil that covers the rock. This layer is called overburden, and the method of its removal is overburden. This procedure, depending on the type of soil, is carried out with the help of bulldozers, draglines, bucket-wheel excavators or scrapers. After the soil layer is removed, you can proceed to crushing the rock itself. Forcrushers, water guns, bulldozers and other equipment are used for this. If the rock in the coal deposit is too dense, then in rare cases, drilling and blasting of the coal is used. This mining method usually covers a fairly large area.

As for the shortcomings of the method, they are as follows:

• Firstly, causing significant environmental damage at the mining site.
• Secondly, all the rock that is mined in this way contains a large amount of harmful impurities in its composition.

The main advantages of open-pit coal mining, in addition to safety, are high speed, as well as economy.

Second method

Closed, or the mine method, as you might guess, is used if the rock lies deep enough underground. On flat terrain, vertical or horizontal channels are formed up to the very seam with coal, after which a mine is created. If the coal seam is located in a mountainous area, then the adit is the place that opens the working.

Underground coal mining can be carried out using longwalls or by the room-and-pillar method. Lavas are long faces. There may be one or more such faces in one mine. In such faces, coal is cut into pieces using a mining combine. In order to deliver raw materials to the surface, the same harvester is used. He loads the rock onto the conveyor. If you use this method, you can get almost all the coal that is contained information. If the coal is not too deep, then the room-and-pillar method is used. In this case, poles and horizontal passages are used, which are formed between them.

Currently, changes are taking place in the coal industry. The technology of an integrated automated production system with the use of powered roof supports is being introduced. A method is being actively developed that will allow remote control of all mining mechanisms.

The advantages of the method include the following:

• the resulting coal will be of very high quality;
• this type of mining is much less harmful to the environment;

Among the shortcomings, it is worth highlighting that this method is the most dangerous mining method, and it will also require significant financial costs for its implementation.

Donetsk Coal Basin

This pool is located on the territory of such regions as Donetsk, Luhansk, Dnepropetrovsk from the side of Ukraine. In addition, it is also located on the territory of the Rostov region of the Russian Federation. The total area of this basin is approximately 60 thousand km2, 50 thousand of which are located on the territory of Ukraine. If we talk about its length, then it is about 650 km in the sublatitudinal direction. At the same time, its maximum width reaches only 200 km. As for the quality and properties of the mined coal, they are very different. The thing is that in the Donetsk coal basin there is a wholemetamorphic series of this fossil. In other words, any coal can be mined here - from brown to anthracite.

Quality kindling charcoal

Quite often the question arises of how to determine the quality of coal suitable for kindling a solid fuel boiler. It is not necessary to know all its properties. Pay attention to the following:

• Caloric content, or heat of combustion. This characteristic describes how much heat a solid fuel can produce when burned.
• Ash content is the main characteristic of the quality of raw materials. The smaller the numerical indicator of this characteristic, the better the coal will be, which means that it will give out more heat during combustion. For quality breeds, the rate is less than 25%.
• It is important to monitor the humidity. It can be external or internal. The outer one can be removed by simply drying the coal, but the inner one can only be removed by burning.

Activated carbon

The structure of this coal is porous, and it is obtained from various other carbon-containing materials that are of organic origin. Carbon in such raw materials will be from 87 to 97%; hydrogen, nitrogen and oxygen are also present. In terms of its chemical composition, this type of coal is more similar to graphite. In addition, this type of raw material can be divided into several classes depending on the type of raw material to be obtained, according to the activation method, activation method and purpose.