Structure

Production

Classification

Main characteristics

Areas of use

Regeneration

Story

Carbonut activated carbons

Documentation

Raw materials and chemical composition

Activated (or activated) carbon (from the Latin carbo activatus) is an adsorbent - a substance with a highly developed porous structure, which is obtained from various carbon-containing materials of organic origin, such as charcoal, coal coke, petroleum coke, coconut shells, walnuts, apricot, olive and other fruit seeds. Activated carbon (carbolene), made from coconut shells, is considered to be the best in terms of cleaning quality and service life, and due to its high strength it can be regenerated many times.

From a chemical point of view, activated carbon is one of the forms of carbon with an imperfect structure that contains virtually no impurities. Activated carbon is 87-97% carbon by weight and may also contain hydrogen, oxygen, nitrogen, sulfur and other substances. In its chemical composition, activated carbon is similar to graphite, a material used, among other things, in ordinary pencils. Activated carbon, diamond, graphite are all different forms of carbon that contain virtually no impurities. According to their structural characteristics, activated carbons belong to the group of microcrystalline varieties of carbon - these are graphite crystallites consisting of planes 2-3 nm in length, which in turn are formed by hexagonal rings. However, the orientation of individual lattice planes relative to each other, typical for graphite, is disrupted in active carbons - the layers are randomly shifted and do not coincide in the direction perpendicular to their plane. In addition to graphite crystallites, activated carbons contain from one to two thirds amorphous carbon, along with this there are heteroatoms. A heterogeneous mass consisting of graphite crystallites and amorphous carbon determines the unique porous structure of activated carbons, as well as their adsorption and physical-mechanical properties. The presence of chemically bound oxygen in the structure of active carbons, which forms surface chemical compounds of a basic or acidic nature, significantly affects their adsorption properties. The ash content of active carbon can be 1-15%, sometimes it is deashed to 0.1-0.2%.

Structure

Activated carbon has a huge number of pores and therefore has a very large surface area, as a result of which it has high adsorption (1 g of active carbon, depending on the manufacturing technology, has a surface area from 500 to 1500 m2). Exactly high level porosity makes activated carbon “activated”. An increase in the porosity of active carbon occurs during a special treatment - activation, which significantly increases the adsorbing surface.

In activated carbons, macro-, meso- and micropores are distinguished. Depending on the size of the molecules that need to be retained on the surface of the coal, coal must be produced with different pore size ratios. Pores in active carbon are classified according to their linear dimensions - X (half-width - for a slit-like pore model, radius - for a cylindrical or spherical one):

• X<= 0,6-0,7 нм - микропоры;
• 0,6-0,7 < Х < 1,5-1,6 нм - супер- микропоры;
• 1,5-1,6 < Х < 100-200 нм - мезопоры;
• X > 100-200 nm - macropores.

Adsorption in micropores (specific volume 0.2-0.6 cm 3 /g and 800-1000 m 2 /g), comparable in size to the adsorbed molecules, is characterized mainly by a volumetric filling mechanism. Similarly, adsorption also occurs in supermicropores (specific volume 0.15-0.2 cm 3 /g) - intermediate areas between micropores and mesopores. In this region, the properties of micropores gradually degenerate, and the properties of mesopores appear. The mechanism of adsorption in mesopores consists of the sequential formation of adsorption layers (polymolecular adsorption), which ends with the filling of the pores according to the mechanism of capillary condensation. For ordinary active carbons, the specific volume of mesopores is 0.02-0.10 cm 3 /g, the specific surface is 20-70 m 2 /g; however, for some active carbons (for example, brightening ones), these figures can reach 0.7 cm 3 /g and 200-450 m 2 /g, respectively. Macropores (specific volume and surface area, respectively, 0.2-0.8 cm 3 /g and 0.5-2.0 m 2 /g) serve as transport channels that bring molecules of absorbed substances to the adsorption space of activated carbon granules. Micro- and mesopores make up the largest part of the surface of activated carbons; accordingly, they make the greatest contribution to their adsorption properties.
Micropores are particularly well suited for the adsorption of small sized molecules, while mesopores are particularly well suited for the adsorption of larger organic molecules. The determining influence on the pore structure of activated carbons is exerted by the feedstock from which they are produced. Coconut shell-based activated carbons are characterized by a larger proportion of micropores, and coal-based activated carbons are characterized by a larger proportion of mesopores. A large proportion of macropores is characteristic of wood-based activated carbons. In active carbon, as a rule, there are all types of pores, and the differential curve of their volume distribution by size has 2-3 maxima. Depending on the degree of development of supermicropores, activated carbons are distinguished with a narrow distribution (these pores are practically absent) and wide (substantially developed).

In the pores of activated carbon, there is intermolecular attraction, which leads to the emergence of adsorption forces (Van der Waals forces), which in nature are similar to the force of gravity with the only difference that they act at the molecular, and not at the astronomical level. These forces cause a reaction similar to a precipitation reaction, in which adsorbed substances can be removed from water or gas streams. Molecules of removed pollutants are held on the surface of activated carbon by intermolecular van der Waals forces. In this way, activated carbons remove contaminants from the substances being purified (unlike, for example, bleaching, when molecules of colored impurities are not removed, but are chemically converted into colorless molecules).
Chemical reactions can also occur between the adsorbed substances and the surface of the activated carbon. These processes are called chemical adsorption or chemisorption, but basically the process of physical adsorption occurs through the interaction of activated carbon and the adsorbed substance. Chemisorption is widely used in industry for gas purification, degassing, metal separation, as well as in scientific research. Physical adsorption is reversible, that is, the adsorbed substances can be separated from the surface and returned to their original state under certain conditions. In chemisorption, the adsorbed substance is bound to the surface through chemical bonds, changing its chemical properties. Chemisorption is not reversible.

Some substances are weakly adsorbed on the surface of ordinary activated carbons. These substances include ammonia, sulfur dioxide, mercury vapor, hydrogen sulfide, formaldehyde, chlorine and hydrogen cyanide. To effectively remove such substances, activated carbons impregnated with special chemicals are used. Impregnated activated carbons are used in specialized areas applications in air and water purification, in respirators, for military purposes, in the nuclear industry, etc.

Production

Furnaces of various types and designs are used to produce activated carbon. The most widespread are: multi-shelf, shaft, horizontal and vertical rotary furnaces, as well as fluidized bed reactors. The basic properties of active carbons and, above all, the porous structure are determined by the type of initial carbon-containing raw material and the method of its processing. First, carbon-containing raw materials are crushed to a particle size of 3-5 cm, then subjected to carbonization (pyrolysis) - roasting at high temperature in an inert atmosphere without air access to remove volatile substances. At the carbonization stage, the framework of the future active carbon is formed - primary porosity and strength.

However, the resulting carbonized carbon (carbonate) has poor adsorption properties because its pore sizes are small and the internal surface area is very small. Therefore, the carbonate is subjected to activation to obtain a specific pore structure and improve adsorption properties. The essence of the activation process is the opening of pores that are in a closed state in the carbon material. This is done either thermochemically: the material is pre-impregnated with a solution of zinc chloride ZnCl 2, potassium carbonate K 2 CO 3 or some other compounds and heated to 400-600 ° C without air access, or, the most common way of treatment - with superheated steam or carbon dioxide CO 2 or their mixture at a temperature of 700-900 °C under strictly controlled conditions.
Activation with water vapor is the oxidation of carbonized products to gaseous products in accordance with the reaction - C + H 2 O -> CO + H 2; or with an excess of water vapor - C + 2H 2 O -> CO 2 + 2H 2. A widespread technique is to supply a limited amount of air into the apparatus for activation simultaneously with saturated steam. Part of the coal burns and the required temperature is reached in the reaction space. The yield of active carbon in this process variant is noticeably reduced. Activated carbon is also produced by thermal decomposition of synthetic polymers (for example, polyvinylidene chloride).

Activation with water vapor makes it possible to obtain coals with an internal surface area of ​​up to 1500 m 2 per gram of coal. Due to this huge surface area, activated carbons are excellent adsorbents. However, not all of this area may be available for adsorption, since large molecules of adsorbed substances cannot penetrate small pores. During the activation process, the necessary porosity and specific surface area develop, and a significant decrease in the mass of the solid substance occurs, called burnout.

As a result of thermochemical activation, coarsely porous activated carbon is formed, which is used for bleaching. As a result of steam activation, finely porous activated carbon is formed, which is used for cleaning.

Next, the activated carbon is cooled and subjected to preliminary sorting and sieving, where the sludge is sifted out, then, depending on the need to obtain the specified parameters, the activated carbon is subjected to additional processing: acid washing, impregnation (impregnation with various chemicals), grinding and drying. After which the activated carbon is packaged in industrial packaging: bags or big bags.

Classification

Activated carbon is classified by the type of raw material from which it is made (coal, wood, coconut, etc.), by the method of activation (thermochemical and steam), by purpose (gas, recovery, brightening and carbon carriers of chemical sorbent catalysts) , as well as by release form. Currently, activated carbon is mainly available in the following forms:

• powdered active carbon,
• granular (crushed, irregularly shaped particles) activated carbon,
• molded activated carbon,
• extruded (cylindrical granules) activated carbon,
• fabric impregnated with active carbon.

Powdered activated carbon has particles less than 0.1 mm in size (more than 90% of the total composition). Powdered carbon is used for industrial liquid treatment, including the treatment of domestic and industrial wastewater. After adsorption, the powdered carbon must be separated from the liquids to be treated by filtration.

Granular activated carbon particles ranging in size from 0.1 to 5 mm (more than 90% of the composition). Granular activated carbon is used for liquid purification, mainly for water purification. When purifying liquids, active carbon is placed in filters or adsorbers. Activated carbons with larger particles (2-5 mm) are used to purify air and other gases.

Molded activated carbon is activated carbon in the form of various geometric shapes, depending on the application (cylinders, tablets, briquettes, etc.). Molded carbon is used to purify various gases and air. When purifying gases, active carbon is also placed in filters or adsorbers.

Extruded carbon is produced with particles in the form of cylinders with a diameter of 0.8 to 5 mm, as a rule, impregnated (soaked) with special chemicals and used in catalysis.

Fabrics impregnated with carbon are available in various shapes and sizes and are most often used for purifying gases and air, for example in automobile air filters.

Main characteristics

Granulometric size (granulometry) is the size of the main part of active carbon granules. Unit of measurement: millimeters (mm), mesh USS (American) and mesh BSS (English). A summary table of USS mesh particle size conversion to millimeters (mm) is given in the corresponding file.

Bulk density is the mass of material that fills a unit volume under the influence of its own weight. The unit of measurement is gram per cubic centimeter (g/cm3).

Surface area is the surface area of ​​a solid divided by its mass. The unit of measurement is square meter to gram of coal (m 2 /g).

Hardness (or strength) - all manufacturers and consumers of activated carbon use significantly different methods for determining strength. Most methods are based on the following principle: a sample of activated carbon is subjected to mechanical stress, and the measure of strength is the amount of fine fraction or medium-sized grinding produced during the destruction of coal. The amount of undestructed coal in percent (%) is taken as a measure of strength.

Humidity - the amount of moisture contained in active carbon. The unit of measurement is percent (%).

Ash content is the amount of ash (sometimes considered only water-soluble) in activated carbon. The unit of measurement is percent (%).

pH of an aqueous extract is the pH value of an aqueous solution after boiling a sample of active carbon in it.

Protective action - measuring the time of adsorption of a certain gas by carbon before the minimum concentration of gas begins to pass through the layer of activated carbon. This test is used for coals used for air purification. Most often, activated carbon is tested for benzene or carbon tetrachloride (aka carbon tetrachloride CCl 4).

CTC adsorption (adsorption on carbon tetrachloride) - carbon tetrachloride is passed through a volume of activated carbon, saturation occurs to a constant mass, then the amount of adsorbed steam is obtained, related to the sample of coal in percent (%).

Iodine index (iodine adsorption, iodine number) is the amount of iodine in milligrams that can adsorb 1 gram of activated carbon, in powder form, from a dilute aqueous solution. Unit of measurement - mg/g.

Methylene blue adsorption is the number of milligrams of methylene blue absorbed by one gram of activated carbon from an aqueous solution. Unit of measurement - mg/g.

Molasses discoloration (molasses number or index, indicator for molasses) - the amount of activated carbon in milligrams required for 50% clarification of a standard molasses solution.

Areas of use

Activated carbon adsorbs well organic, high-molecular substances with a non-polar structure, for example: solvents (chlorinated hydrocarbons), dyes, oil, etc. Adsorption capabilities increase with decreasing solubility in water, with greater non-polarity of the structure and increasing molecular weight. Activated carbons are good at adsorbing vapors of substances with relatively high boiling points (for example, benzene C 6 H 6), and less so for volatile compounds (for example, ammonia NH 3). At relative vapor pressures p p /p us less than 0.10-0.25 (p p is the equilibrium pressure of the adsorbed substance, p us is the saturated vapor pressure), activated carbon slightly absorbs water vapor. However, when p p /p us is more than 0.3-0.4, noticeable adsorption is observed, and in the case of p p /p us = 1, almost all micropores are filled with water vapor. Therefore, their presence may complicate the absorption of the target substance.

Activated carbon is widely used as an adsorbent that absorbs vapors from gas emissions (for example, when cleaning air from carbon disulfide CS 2), trapping vapors of volatile solvents for the purpose of their recovery, for purifying aqueous solutions (for example, sugar syrups and alcoholic beverages), drinking water and waste water. water, in gas masks, in vacuum technology, for example, for creating sorption pumps, in gas adsorption chromatography, for filling odor absorbers in refrigerators, blood purification, absorption of harmful substances from the gastrointestinal tract, etc. Activated carbon can also be a carrier of catalytic additives and a catalyst polymerization. To impart catalytic properties to activated carbon, special additives are added to the macro- and mesopores.

With the development of industrial production of activated carbon, the use of this product is steadily increasing. Currently, activated carbon is used in many water purification processes, the food industry, and chemical technology processes. In addition, waste gas and wastewater treatment is mainly based on activated carbon adsorption. And with the development of nuclear technology, activated carbon is the main adsorbent of radioactive gases and wastewater at nuclear power plants. In the 20th century, the use of activated carbon appeared in complex medical processes, such as hemofiltration (blood purification with activated carbon). Activated carbon is used:

Water is classified as wastewater, groundwater and drinking water. A characteristic feature of this classification is the concentration of pollutants, which may be solvents, pesticides and/or halogenated hydrocarbons such as chlorinated hydrocarbons. The following concentration ranges are distinguished, depending on solubility:

• 10-350 g/liter for drinking water,
• 10-1000 g/liter for groundwater,
• 10-2000 g/liter for wastewater.

Water treatment of swimming pools does not fit this classification, since here we are dealing with dechlorination and deozonation, and not with pure adsorption removal of the pollutant. Dechlorination and deozonation are effectively applied in swimming pool water treatment using coconut shell activated carbon, which has the advantage of large adsorption surface and therefore has excellent dechlorination effect with high density. High density allows reverse flow without washing out the activated carbon from the filter.

Granular activated carbon is used in fixed stationary adsorption systems. The contaminated water flows through a permanent layer of activated carbon (mainly from top to bottom). For this adsorption system to function freely, the water must be free of any solid particles. This can be guaranteed by appropriate pre-treatment (eg sand filter). Particles that enter the stationary filter can be removed by the counterflow of the adsorption system.

Many manufacturing processes emit harmful gases. These toxic substances should not be released into the air. The most common toxic substances found in the air are solvents, which are necessary for the production of everyday materials. For the separation of solvents (mainly hydrocarbons, such as chlorinated hydrocarbons), activated carbon can be successfully used due to its water-repellent properties.

Air purification is divided into air pollution purification and solvent recovery according to the amount and concentration of pollutant in the air. At high concentrations, it is cheaper to recover solvents from activated carbon (eg via steam). But if toxic substances exist at very low concentrations or in a mixture that cannot be reused, disposable molded activated carbon is used. Molded activated carbon is used in stationary adsorption systems. Contaminated ventilation streams pass through a permanent layer of coal in one direction (mainly from bottom to top).

One of the main areas of application of impregnated activated carbon is gas and air purification. Polluted air as a result of many technical processes contains toxic substances that cannot be completely removed by conventional activated carbon. These toxic substances, mostly inorganic or unstable, polar substances, can be highly toxic even at low concentrations. In this case, impregnated active carbon is used. Sometimes by various intermediate chemical reactions between the pollutant component and the active substance in the activated carbon, the pollutant can be completely removed from the polluted air. Activated carbons are impregnated (impregnated) with silver (for purification of drinking water), iodine (for purification from sulfur dioxide), sulfur (for purification from mercury), alkali (for purification from gaseous acids and gases - chlorine, sulfur dioxide, nitrogen dioxide, etc. . etc.), acid (for cleaning from gaseous alkalis and ammonia).

Regeneration

Since adsorption is a reversible process and does not change the surface or chemical composition of the activated carbon, contaminants can be removed from the activated carbon through desorption (release of adsorbed substances). Van der Wals's force, which is the main one driving force in adsorption, is weakened, therefore, in order for the contaminant to be removed from the surface of the coal, three technical methods are used:

• Temperature fluctuation method: the effect of the van der Wals force decreases as the temperature increases. The temperature increases due to a hot stream of nitrogen or an increase in steam pressure at a temperature of 110-160 °C.
• Pressure Oscillation Method: As the partial pressure decreases, the effect of the Van Der Wals force decreases.
• Extraction - desorption in liquid phases. Adsorbed substances are removed chemically.

All these methods have disadvantages, since adsorbed substances cannot be completely removed from the surface of the coal. A significant amount of pollutant remains in the pores of the activated carbon. When using steam regeneration, 1/3 of all adsorbed substances still remain in the activated carbon.

Chemical regeneration refers to the treatment of a sorbent with liquid or gaseous organic or inorganic reagents at a temperature, usually not higher than 100 °C. Both carbon and non-carbon sorbents are chemically regenerated. As a result of this treatment, the sorbate is either desorbed without changes, or the products of its interaction with the regenerating agent are desorbed. Chemical regeneration often occurs directly in the adsorption apparatus. Most chemical regeneration methods are highly specialized for a certain type of sorbate.

Low-temperature thermal regeneration is the treatment of the sorbent with steam or gas at 100-400 °C. This procedure is quite simple and in many cases it is carried out directly in the adsorbers. Due to its high enthalpy, water vapor is most often used for low-temperature thermal regeneration. It is safe and available in production.

Chemical regeneration and low-temperature thermal regeneration do not ensure complete recovery of adsorption carbons. Thermal regeneration is a very complex, multi-stage process that affects not only the sorbate, but also the sorbent itself. Thermal regeneration is close to the technology for producing active carbons. During the carbonization of various types of sorbates on coal, most of the impurities decompose at 200-350 °C, and at 400 °C about half of the total adsorbate is usually destroyed. CO, CO 2, CH 4 - the main decomposition products of organic sorbate are released when heated to 350 - 600°C. In theory, the cost of such regeneration is 50% of the cost of new activated carbon. This indicates the need to continue the search and development of new highly effective methods for regenerating sorbents.

Reactivation - complete regeneration of activated carbon using steam at a temperature of 600 °C. The pollutant is burned at this temperature without burning coal. This is possible due to the low oxygen concentration and the presence of a significant amount of steam. Water vapor selectively reacts with adsorbed organics that are highly reactive in water at these high temperatures, resulting in complete combustion. However, minimal coal combustion cannot be avoided. This loss must be compensated by new coal. After reactivation, it often happens that the activated carbon shows greater internal surface and higher reactivity than the original carbon. These facts are due to the formation of additional pores and coking contaminants in activated carbon. The structure of the pores also changes - they increase. Reactivation is performed in a reactivation oven. There are three types of kilns: rotary kilns, shaft kilns and variable gas flow kilns. A variable gas flow furnace has advantages due to low combustion and friction losses. Activated carbon is loaded into the air stream and combustion gases can be carried upward through the grate. Activated carbon becomes partially fluid due to the intense gas flow. The gases also transport combustion products when reactivated from the activated carbon into the afterburner. Air is added to the afterburner so gases that were not completely ignited can now be burned. The temperature increases to approximately 1200 °C. After combustion, the gas flows to the gas washer, in which the gas is cooled to a temperature between 50-100 °C as a result of cooling with water and air. In this chamber, hydrochloric acid, which is formed by adsorbed chlorocarbons from purified activated carbon, is neutralized with sodium hydroxide. Due to the high temperature and rapid cooling, the formation of toxic gases (such as dioxins and furans) does not occur.

Story

The earliest historical mention of the use of coals dates back to Ancient India, where the Sanskrit scriptures stated that drinking water must first be passed through coal, kept in copper vessels and exposed to sunlight.

Unique and beneficial features coals were also known in Ancient Egypt, where charcoal was used for medicinal purposes as early as 1500 BC. e.

The ancient Romans also used coal to purify drinking water, beer and wine.

At the end of the 18th century, scientists knew that carbolene was capable of absorbing various gases, vapors and dissolved substances. In everyday life, people have observed: if, when boiling water, a few charcoals are thrown into a pan where dinner was previously cooked, then the taste and smell of food disappear. Over time, activated carbon began to be used to purify sugar, to capture gasoline in natural gases, for dyeing fabrics, and tanning leather.

In 1773, German chemist Karl Scheele reported the adsorption of gases on charcoal. It was later discovered that charcoal could also discolour liquids.

In 1785, the St. Petersburg pharmacist T. E. Lovitz, who later became an academician, first drew attention to the ability of activated carbon to purify alcohol. As a result of repeated experiments, he found that even simply shaking wine with charcoal powder makes it possible to obtain a much purer and higher-quality drink.

In 1794, charcoal was first used in an English sugar factory.

In 1808, charcoal was first used in France to clarify sugar syrup.

In 1811, during the preparation of black shoe cream, the bleaching ability of bone char was discovered.

In 1830, one pharmacist, conducting an experiment on himself, ingested a gram of strychnine and remained alive because he simultaneously swallowed 15 grams of activated carbon, which adsorbed this strong poison.

In 1915, the world's first filtering carbon gas mask was invented in Russia by Russian scientist Nikolai Dmitrievich Zelinsky. In 1916 it was adopted by the armies of the Entente. The main sorbent material in it was activated carbon.

Industrial production of activated carbon began at the beginning of the 20th century. In 1909, the first batch of powdered active carbon was produced in Europe.

During the First World War, activated carbon from coconut shells was first used as an adsorbent in gas masks.

Currently, activated carbons are one of the best filter materials.

Carbonut activated carbons

The company offers a wide range of Carbonut activated carbons, which have proven themselves in a wide variety of technological processes and industries:

• Carbonut WT for the purification of liquids and water (ground, waste and drinking water, as well as for water treatment),
• Carbonut VP for purifying various gases and air,
• Carbonut GC for the extraction of gold and other metals from solutions and pulps in the mining and motellurgical industry,
• Carbonut CF for cigarette filters.

Carbonut activated carbons are produced exclusively from coconut shells, since coconut activated carbons have the best cleaning quality and the highest absorption capacity (due to the presence of more pores and, accordingly, a larger surface area), the longest service life (due to high hardness and the possibility of repeated regeneration) , lack of desorption of absorbed substances and low ash content.

Carbonut activated carbons have been produced since 1995 in India using automated and high-tech equipment. The production has a strategically important location, firstly, in close proximity to the source of raw materials - coconut, and secondly, in close proximity to sea ports. Coconut grows year-round, providing an uninterrupted source of quality raw materials in large quantities, with minimal delivery costs. The proximity of seaports also avoids additional logistics costs. All stages of the technological cycle in the production of Carbonut activated carbon are strictly controlled: this includes careful selection of input raw materials, control of basic parameters after each intermediate stage of production, as well as quality control of the final, finished product in accordance with established standards. Carbonut activated carbons are exported almost all over the world and, due to their excellent price-quality ratio, are in wide demand.

Documentation

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If you want to buy Activated carbon in Moscow, Moscow region, Mytishchi, St. Petersburg - contact the company’s managers. Delivery to other regions is also available Russian Federation.

A ghost town without coal. This was the Japanese Hashima. In the 1930s it was recognized as the most populous. 5,000 people fit on a tiny piece of land. They all worked in coal production.

The island turned out to be literally made of a stone source of energy. However, by the 1970s, coal reserves were depleted.

Everyone left. All that remained was the dug up island and the buildings on it. Tourists and Japanese call Hashima a ghost. The island clearly shows the importance of coal and the inability of humanity to live without it. There is no alternative.

There are only attempts to find her. Therefore, let's pay attention to the modern hero, and not to the vague prospects.

Description and properties

Coal is a rock of organic origin. This means that the stone is formed from the decomposed remains of plants and animals. In order for them to form a dense thickness, constant accumulation and compaction is required.

Suitable conditions at the bottom of reservoirs. Where there is coal deposits, once there were seas and lakes. Dead organisms sank to the bottom and were pressed down by the water column. This is how it was formed. Coal is a consequence of its further compression under pressure not only of water, but also of new layers of organic matter.

Basic coal reserves belong to the Paleozoic era. 280,000,000 years have passed since its end. This is the era of giant plants and dinosaurs, an abundance of life on the planet. It is not surprising that it was then that organic deposits accumulated especially actively.

Most often, coal was formed in swamps. Their waters have little oxygen, which prevents the complete decomposition of organic matter.

Externally coal deposits resemble burnt wood. The chemical composition of the rock is a mixture of high-molecular carbon aromatic compounds and volatile substances with water.

Mineral impurities are insignificant. The ratio of components is not stable. Depending on the predominance of certain elements, they distinguish types of coal. The main ones include anthracite.

The brown variety of coal is saturated with water, and therefore has a low calorific value. It turns out that the rock is not suitable as fuel, like stone. And brown coal has found other uses. Which?

This will be given special attention. In the meantime, let’s figure out why water-saturated rock is called brown. The reason is the color.

Coal is brownish, without shine, friable. From a geological point of view, the mass can be called young. That is, the “fermentation” processes in it are not completed. Therefore, the stone has a low density and during combustion a lot of volatile substances are formed.

Fossil coal anthracite type - fully formed. It is denser, harder, blacker, shiny. It takes 40,000,000 years for brown rock to become this way. Anthracite contains a high proportion of carbon - about 98%.

Naturally, the heat transfer of black coal is high, which means that the stone can be used as fuel.

Coal formations are most often found in swamps

The brown species in this role is used only for heating private houses. They don't need record energy levels.

All that is needed is ease of handling fuel, and anthracite is problematic in this regard. Lighting black coal is not easy. Manufacturers and railway workers got used to it. The labor costs are worth it, because it is not only energy-intensive, but also does not sinter.

Hard coal - fuel, the combustion of which leaves ash. What is it made of if organic matter turns into energy? Remember the note about mineral impurities? It is the inorganic component of the stone that remains at the bottom of the furnaces.

A lot of ash remains in the Chinese deposit in Liuhuangou province. Anthracite deposits burned there for almost 130 years. The fire was extinguished only in 2004. Every year 2,000,000 tons of rock were burned.

So do the math how much coal wasted. The raw materials could be useful not only as fuel.

Application of coal

Coal is called solar energy trapped in stone. Energy can be transformed. It doesn't have to be thermal.

The energy obtained from burning rock is converted, for example, into electricity. Coal combustion temperature the brown type almost reaches 2,000 degrees. To obtain electricity from anthracite, it will take about 3,000 Celsius.

Coal is used as fuel

If we talk about the fuel role of coal, it is used not only in its pure form.

Laboratories have learned how to produce liquid and gaseous fuel from organic rock, and metallurgical plants have long used coke.

It is obtained by heating coal to 1,100 degrees without oxygen. Coke is a smokeless fuel. The possibility of using briquettes as iron ore reducers is also important for metallurgists. So, coke comes in handy when casting.

Coke is also used as a blending agent. This is the name given to the mixture of initial elements of the future alloy. Being loosened by coke, the charge is easier to melt. By the way, some components for alloys are also obtained from anthracite.

It may also contain gallium as impurities - rare metals that are rarely found anywhere else.

They also strive to buy coal for the production of carbon-graphite composite materials. Composites are masses made of several components, with a clear boundary between them.

Artificially created materials are used, for example, in aviation. Here, composites increase the strength of parts.

Carbon masses can withstand both very high and low temperatures and are used in catenary support racks.

In general, composites have become firmly established in all areas of life. Railway workers are laying them on new platforms.

Supports for building structures are made from nanomodified raw materials. In medicine, composites are used to fill chips in bones and other damage that cannot be replaced with metal prosthetics. Here what kind of coal multifaceted and multifunctional.

Chemists have developed a method for producing plastics from coal. At the same time, waste does not disappear. The low-grade fraction is pressed into briquettes.

They serve as fuel, which is suitable for both private homes and industrial workshops. Fuel briquettes contain a minimum of hydrocarbons. They, in fact, are the females valuable in coal.

From it you can obtain pure benzene, toluene, xylenes, and coumorane resins. The latter, for example, serve as the basis for paint and varnish products and interior finishing materials such as linoleum.

Some hydrocarbons are aromatic. People are familiar with the smell of mothballs. But few people know that it is produced from coal.

In surgery, naphthalene serves as an antiseptic. In the household, the substance fights moths. In addition, naphthalene can protect against the bites of a number of insects. Among them: flies, gadflies, horseflies.

Total, coal in bags purchase for the production of more than 400 types of products.

Many of them are by-products obtained from coke production. Interestingly, the cost of additional lines is generally higher than that of coke.

If we consider the average difference between coal and goods made from it, it is 20-25 times.

That is, production is very profitable and pays off quickly. Therefore, it is not surprising that scientists are looking for more and more new technologies for processing sedimentary rock. There must be supply for growing demand. Let's get to know him.

Coal mining

Coal deposits are called basins. There are over 3,500 of them in the world. The total area of ​​the basins is about 15% of the land area. The USA has the most coal.

23% of the world's reserves are concentrated there. Hard coal in Russia– this is 13% of total reserves. China has bronze. 11% of the rock is hidden in its depths.

Most of them are anthracite. In Russia, the ratio of brown coal to black is approximately the same. In the USA, the brown type of rock predominates, which reduces the importance of deposits. Despite the abundance of brown coal, the US deposits are striking not only in volume, but also in scale.

The reserves of the Appalachian coal basin alone amount to 1,600 billion tons. Russia's largest basin, by comparison, stores only 640 billion tons of rock. We are talking about the Kuznetsk deposit.

It is located in the Kemerovo region. A couple more promising basins have been discovered in Yakutia and Tyva. In the first region, the deposits were called Elga, and in the second - Elegetian. The deposits of Yakutia and Tyva are of the closed type. That is, the rock is not near the surface, but at depth.

It is necessary to build mines, adits, shafts. It's uplifting coal price. But the scale of the deposits costs money. As for the Kuznetsk basin, they operate in a mixed system. About 70% of raw materials are extracted from the depths using hydraulic methods.

30% of coal is mined openly using bulldozers. They are sufficient if the rock lies near the surface and the covering layers are loose.

Coal is also mined openly in China. Most of China's deposits are located far outside the cities. However, this did not prevent one of the deposits from causing inconvenience to the population of the country. This happened in 2010.

Beijing has sharply increased its requests for coal from Inner Mongolia. It is considered a province of the People's Republic of China. So many trucks loaded with goods hit the road that Highway 110 was stopped for almost 10 days. The traffic jam began on August 14th, and only resolved on the 25th.

True, it could not have happened without road work. Coal trucks made the situation worse. Highway 110 is a state road. So, not only was the coal delayed in transit, but other contracts were also under threat.

You can find videos on the Internet where drivers driving along a Chinese highway in August 2010 report that it took about 5 days to cover the 100-kilometer stretch.

1. Chemical properties of coal

2. Classification of coal

3. Formation of coal

4. Coal reserves

Coal is sedimentary rock, representing the deep decomposition of plant remains (tree ferns, horsetails and mosses, as well as the first gymnosperms).

Chemical properties of coal

By chemical composition coal It is a mixture of high molecular weight aromatic compounds with a high mass fraction of carbon, as well as water and volatile substances with small amounts of mineral impurities. Such impurities form ash when burning coal. Fossil coals differ from each other in the ratio of their constituent components, which determines their heat of combustion. A number of organic compounds that make up coal have carcinogenic properties.

Most coal deposits were formed in the Paleozoic, mainly during the Carboniferous period, approximately 300-350 million years ago. By chemical composition coal It is a mixture of high molecular weight polycyclic aromatic compounds with a high mass fraction of carbon, as well as water and volatile substances with small amounts of mineral impurities, which form ash when burning coal. Fossil coals differ from each other in the ratio of their constituent components, which determines their heat of combustion. A number of organic compounds that make up coal have carcinogenic properties. The carbon content of coal, depending on its type, ranges from 75% to 95%.

Coal, a solid combustible mineral of plant origin; a type of fossil coal with a higher carbon content and greater density than brown coal. It is a dense rock of black, sometimes gray-black color with a shiny, semi-matte or matte surface. Contains 75-97% or more carbon; 1.5-5.7% hydrogen; 1.5-15% oxygen; 0.5-4% sulfur; up to 1.5% nitrogen; 45-2% volatiles; the amount of moisture ranges from 4 to 14%; ash - usually from 2-4% to 45%. The highest calorific value, calculated for the wet ash-free mass of coal, is not less than 23.8 MJ/kg (5700 kcal/kg).

Coal is the remains of plants that died many millions of years ago, the decay of which was interrupted as a result of the cessation of air supply. Therefore, they could not release the carbon taken from it into the atmosphere. The access of air ceased especially abruptly where swamps and swampy forests sank as a result of tectonic movements and changes in climatic conditions and were covered with other substances. At the same time, plant remains were transformed under the influence of bacteria and fungi (coalified) into peat and further into brown coal, hard coal, anthracite and graphite.

Based on the composition of the main component - organic matter, coals are divided into three genetic groups: humolites, sapropelites, saprohumolites. Humolites predominate, the starting material of which was the remains of higher land plants. Their deposition occurred mainly in swamps that occupied the low-lying coasts of seas, bays, lagoons, and freshwater basins. As a result of biochemical decomposition, the accumulating plant material was processed into peat, with a significant influence on the water content and chemical composition of the aquatic environment. The carbon content of hard coal ranges from 75 to 90 percent. The exact composition is determined by the location and conditions of coal transformation. Mineral impurities are either in a finely dispersed state in the organic mass, or in the form of thin layers and lenses, as well as crystals and concretions. The source of mineral impurities in fossil coals can be inorganic parts of coal-forming plants, mineral new formations that precipitate from water solutions circulating in peat bogs, etc.

As a result of prolonged exposure to elevated temperatures and pressure, brown coals are transformed into hard coals, and the latter into anthracite. The irreversible gradual change in the chemical composition, physical and technological properties of organic matter at the stage of transformation from brown coal to anthracite is called coal metamorphism.

The structural and molecular rearrangement of organic matter during metamorphism is accompanied by a consistent increase in the relative carbon content in coal, a decrease in the oxygen content, and the release of volatile substances; the hydrogen content, calorific value, hardness, density, fragility, optics, electricity and other physical properties change. Hard coals at the middle stages of metamorphism acquire sintering properties - the ability of gelified and lipoid components of organic matter to transform when heated under certain conditions into a plastic state and form a porous monolith - coke. In zones of aeration and active action of groundwater near the Earth's surface, coals undergo oxidation.

In terms of its effect on the chemical composition and physical properties, oxidation has the opposite direction compared to metamorphism:

coal loses its strength properties and sinterability;

the relative content of oxygen in it increases, the amount of carbon decreases, humidity and ash content increases, and the heat of combustion sharply decreases.

The depth of oxidation of fossil coals, depending on modern and ancient topography, the position of the groundwater table, the nature of climatic conditions, material composition and metamorphism, ranges from 0 to 100 meters vertically.

The specific gravity of coal is 1.2 - 1.5 g/cm3, calorific value is 35,000 kJ/kg. Hard coal is considered suitable for technological use if, after combustion, the ash content is 30% or less. Primitive mining of fossil coals has been known since ancient times (Greece). Coal began to play a significant role as a fuel in Britain in the 17th century. The formation of the coal industry is associated with the use of coal as coke in the smelting of cast iron. Since the 19th century, transport has been a major purchaser of coal. The main areas of industrial use of coal: production of electricity, metallurgical coke, combustion for energy purposes, production of various (up to 300 types) products through chemical processing. The consumption of coal is increasing for the production of high-carbon carbon-graphite structural materials, rock wax, plastics, synthetic, liquid and gaseous high-calorie fuels, aromatic products by hydrogenation, and highly nitrous acids for fertilizers. Coke obtained from coal is required in large quantities for metallurgical industry.

Coke is produced at coke plants. Coal is subjected to dry distillation (coking) by heating in special coke ovens without air access to a temperature of C. This produces coke - a solid porous substance. In addition to coke, dry distillation of coal also produces volatile products, which, when cooled to 25-75 C, form coal tar, ammonia water and gaseous products. Coal tar undergoes fractional distillation, resulting in several fractions:

light oil (boiling point up to 170 C) it contains aromatic hydrocarbons (benzene, toluene, acids and other substances;

medium oil (boiling point 170-230 C). These are phenols, naphthalene;

heavy oil (boiling point 230-270 C). These are naphthalene and its homologues

anthracene oil - anthracene, phenathrene, etc.

The composition of gaseous products (coke oven gas) includes benzene, toluene, xyols, phenol, ammonia and other substances. After purification from ammonia, hydrogen sulfide and cyanide compounds, crude benzene is extracted from coke oven gas, from which individual hydrocarbons and a number of other valuable substances are isolated.

Amorphous carbon in the form of coal, as well as many carbon compounds, play a vital role in modern life as sources of various types energy. When coal burns, it produces heat that is used for heating, cooking, and many industrial processes. Most of the heat received is converted into other types of energy and spent on performing mechanical work.

Coal is a solid fuel, a mineral of plant origin. It is a dense rock of black, sometimes dark gray color with a shiny matte surface. Contains 75-97% carbon, 1.5-5.7% hydrogen, 1.5-15% oxygen, 0.5-4% sulfur, up to 1.5% nitrogen, 2-45% volatile substances, the amount of moisture ranges from 4 to 14%. The highest calorific value calculated for the wet ash-free mass of coal is not less than 238 MJ/kg.

Coal is formed from the decomposition products of organic substances of higher plants, which have undergone changes under pressure conditions of various rocks of the earth's crust and under the influence of temperature. With an increase in the degree of metamorphism in the combustible mass, coal increases the carbon content and at the same time reduces the amount of oxygen, hydrogen, and volatile substances. The heat of combustion of coal also changes.

Characteristic physical properties of coal:

density (g/cm3) - 1.28-1.53;

mechanical strength (kg/cm2) - 40-300;

specific heat capacity C (Kcal/g deg) - 026-032;

light refractive index - 1.82-2.04.

The largest coal deposits in the world in terms of production volume are the Tunguska, Kuznetsk, Pechora basins - in the Russian Federation; Karaganda - in Kazakhstan; Appalachian and Pennsylvania basins - in the USA; Ruhrsky - in the Republic of Germany; Great Yellow River - in China; South Wales - in England; Valenciennes - in France, etc.

The uses of coal are varied. It is used as household, energy fuel, metallurgical and chemical industry, as well as for extracting rare and trace elements from it. Coal, coke, and heavy industries process coal using the coking method. Coking is an industrial method of processing coal by heating to 950-1050 C without air access. The main coke-chemical products are: coke oven gas, products from the processing of raw benzene, coal tar, and ammonia.

Hydrocarbons are removed from coke oven gas by washing in scrubbers with liquid absorption oils. After distillation from the oil, distillation from the fraction, purification and repeated rectification, pure commercial products are obtained, such as benzene, toluene, xylenes, etc. From the unsaturated compounds contained in crude benzene, coumarone resins are obtained, which are used for the production of varnishes, paints, linoleum and in the rubber industry. Cyclopentadiene, which is also obtained from coal, is also a promising raw material. Coal - raw materials for the production of naphthalene and other individual aromatic hydrocarbons. The most important processing products are pyridine bases and phenols.

Through processing, a total of more than 400 different products can be obtained, the cost of which, compared to cost coal itself, increases by 20-25 times, and by-products obtained at coke plants exceed price the coke itself.

The combustion (hydrogenation) of coal to form liquid fuel is very promising. To produce 1t of black gold, 2-3t of coal is consumed. Artificial graphite is obtained from coal. They are used as inorganic raw materials. When processing hard coal, vanadium, germanium, sulfur, gallium, molybdenum, and lead are extracted from it on an industrial scale. Ash from coal combustion, mining and processing wastes are used in the production of building materials, ceramics, refractory raw materials, alumina, and abrasives. In order to optimally use coal, it is enriched (removing mineral impurities).

Coal contains up to 97% carbon; it can be said to be the basis of all hydrocarbons, i.e. They are based on carbon atoms. Often we encounter amorphous carbon in the form of coal. In structure, amorphous carbon is the same as graphite, but in a state of extremely fine grinding. Practical use amorphous forms of carbon are varied. Coke and coal are used as reducing agents in metallurgy for iron smelting.

Classification of coal

Coal is formed from the decomposition products of organic remains of higher plants that have undergone changes (metamorphism) under conditions of pressure from the surrounding rocks of the earth's crust and relatively high temperatures. With an increase in the degree of metamorphism in the combustible mass of coal, the carbon content consistently increases and at the same time the amount of oxygen, hydrogen, and volatile substances decreases; The heat of combustion, the ability to sinter and other properties also change. The industrial classification adopted in the USSR is based on changes in these qualities, determined based on the results of thermal decomposition of coal (yield of volatile substances, characteristics of non-volatile residue).

Coal by grade:

long flame (D),

gas (G),

gas fatty (GZh),

fatty (F),

coke fatty (QF),

coke (K),

lean sintering (OS),

skinny (T),

low-caking (SS),

semi-anthracite (PA)

anthracite (A).

Sometimes anthracites are classified as a separate group. For coking, mainly coal of grades G, Zh, K and OS, partially D and T are used. As coal passes from grade D to grades T-A, the moisture in the working fuel decreases from 14% for grade D to 4 .5-5.0% for brands T-A; reducing the oxygen content (in the combustible mass) from 15% to 1.5%; hydrogen - from 5.7% to 1.5%; content sulfur, nitrogen and ash does not depend on belonging to one brand or another. The heat of combustion of the combustible mass of hard coal consistently increases from 32.4 MJ/kg (7750 kcal/kg) for grade D to 36.2–36.6 MJ/kg (8650–8750 kcal/kg) for grade K and decreases to 35 .4–33.5 MJ/kg (8450–8000 kcal/kg) for PA and A brands.

Based on the size of the pieces obtained during mining, coal is classified into:

slab (P) - more than 100 mm,

large (K) - 50-100 mm,

nut (O) - 26-50 mm,

small (M) - 13-25 mm,

seed (C) - 6-13 mm,

piece (W) - less than 6 mm,

private (P) - not limited by size.

The brand and size of the pieces of coal are indicated by letter combinations - DK, etc.

The classification of hard coal in a number of Western European countries is based on approximately the same principles as in the USSR. IN USA The most common classification of hard coal is based on the yield of volatile substances and heat of combustion, according to which they are divided into subbituminous with a high yield of volatile substances (corresponding to Soviet grades D and G), bituminous with an average yield of volatile substances (corresponding to grades PZh and K), bituminous with a low yield of volatile substances (OS and T) and anthracite coals, divided into semi-anthracites (partially T and A), anthracites themselves and meta-anthracites (A). In addition, there is an international classification of hard coal, based on the content of volatile substances, caking ability, coking ability and reflecting the technological properties of coals.

Formation of coal

The formation of coal is characteristic of all geological systems from the Silurian and Devonian; coal is very widely distributed in the deposits of the Carboniferous, Permian and Jurassic systems. Coal occurs in the form of layers of varying thickness (from fractions of a meter to several tens of meters or more). The depth of occurrence of coals varies - from reaching the surface to 2000-2500 m and deeper. With the modern level of mining technology, coal can be mined by opencast mining to a depth of 350 m.

For the formation of coal, abundant accumulation of plant matter is necessary. In ancient peat bogs, starting from the Devonian period, organic matter accumulated, from which fossil coals were formed without access to oxygen. Most commercial fossil coal deposits date from this period, although younger deposits also exist. The oldest coals are estimated to be about 350 million years old.

Coal is formed when decaying plant material accumulates faster than bacterial decomposition occurs. An ideal environment for this is created in swamps, where stagnant water, depleted of oxygen, prevents the activity of bacteria and thereby protects the plant mass from complete destruction. At a certain stage process The acids released during this process prevent further bacterial activity. This is how peat arises - the original product for the formation of coal. If it is then buried under other sediments, the peat experiences compression and, losing water and gases, is converted into coal.

Under the pressure of a sediment layer 1 kilometer thick, a 20-meter layer of peat produces a layer of brown coal 4 meters thick. If the burial depth plant material reaches 3 kilometers, then the same layer of peat will turn into a layer of coal 2 meters thick. At greater depths, about 6 kilometers, and at higher temperatures, a 20-meter layer of peat becomes a layer of anthracite 1.5 meters thick.

The method of coal mining depends on the depth of its occurrence. Mining is carried out by open-pit mining if the depth of the coal seam does not exceed 100 meters. There are also frequent cases when, with an ever-deepening coal mine, it is further profitable to develop a coal deposit using the underground method. Mines are used to extract coal from great depths. The deepest mines in the territory Russia Coal is mined from a level of just over 1200 meters.

Coal-bearing deposits, along with coal, contain many types of georesources that have consumer significance. These include host rocks such as raw materials for the construction industry, groundwater, coal bed methane, rare and trace elements, including valuable metals and their compounds. For example, some coals are enriched with germanium.

Coal reserves

General geological reserves of hard coal in the USSR are about 4,700 billion tons (according to 1968 estimates), including by grade (in billion tons): D - 1,719; D—G—331; G - 475; GZh - 69.4; F - 156; QOL - 21.5; K - 105; OS - 88.2; SS - 634; T - 205; T-A - 540; PA, A - 139.

The largest reserves of coal in the USSR are located in the Tunguska basin. The largest developed coal basins in the USSR are Donetsk, Kuznetsk, Pechora, Karaganda; V USA- Appalachian and Pennsylvanian, in Poland - Upper Silesian and its continuation in Czechoslovakia - Ostrava-Karvinsky, in Germany— Ruhrsky, in China- Big Huanghebass, in England— South Wales, in France- Valenciennes and in Belgium - Brabant. The uses of coal are varied.

It is used as a household, energy fuel, raw material for the metallurgical and chemical industries, as well as for extracting rare and trace elements from it.

For two decades in a row, coal was in the shadow of the oil boom. Mountains of unsaleable coal rose into the sky. Numerous mines were closed, hundreds of thousands of miners lost their jobs. The Appalachian region of the United States, once a thriving coal basin, has become one of the world's darkest disaster areas. A chaotic transition to cheap, imported food, mainly from the Middle East, under pressure from monopolists. oil condemned coal to the role of “Cinderella”, deprived of a future. However, this did not happen in some countries, including in the former USSR, which took into account the advantages of an energy structure based on national resources.

Coal reserves are scattered throughout the world. Most industrial countries they are not deprived. The earth is surrounded by two rich coal zones. One extends through the countries of the former USSR, through China, North America to Central Europe. The other, narrower and less rich, runs from southern Brazil through South Africa to Eastern Australia.

The most significant deposits hard coal are located in the countries of the former USSR, the USA and China. Coal dominates in western Europe. The main coal basins in Eurasia: South Wales, Valenciennes-Liège, Saar-Lotarginsky, Ruhrsky, Asturian, Kizelovsky, Donetsk, Taimyrsky, Tungussky, South Yakutsky, Funshunsky; in Africa: Jerada, Abadla, Enugu, Huanqui, Witbank; in Australia: Great Syncline, New South Wales; in North America: Green River, Junnta, San Juan River, Western, Illinois, Appalachian, Sabinas, Texas, Pennsylvania; in the burning continent: Carare, Junin, Santa Catarina, Concepcion. In Ukraine, the Lviv-Volyn basin and the Donbass, rich in deposits, should be noted.

Sources

bse.sci-lib.com/ Great Soviet Encyclopedia

ru.wikipedia.org Wikipedia - the free encyclopedia

www.bankreferatov.ru abstracts

dic.academic.ru Dictionaries and encyclopedias on Academician

geography.kz Geography

www.bibliotekar.ru Librarian

poddoni.com/ PalletEk

Investor Encyclopedia. 2013 .

Synonyms:

Rocks formed in the thickness of the earth's crust, due to the influence of temperature, pressure, movement of the earth's crust and other physical and chemical conditions, undergo stages of metamorphism: peat, brown coal, coal, anthracite.

Coal

Coal contains moisture and mineral impurities. Moisture in coal reduces the heat of combustion. The most harmful impurity in coal is sulfur in various compounds (pyrite, calcium, iron sulfate). When burning coal with sulfur compounds, sulfur dioxide (sulfur dioxide) is formed, which has a harmful effect on human health, causes corrosion of metals, and poisons the atmosphere. Relatively low sulfur content (1%-2%) in coal from the Donetsk basin. In the central and northern coal basins, the sulfur content is already 3.5% or more.

Chemical composition of coal:

• Carbon – 50% - 96%
• Hydrogen – 3% - 6%
• Oxygen – 25% - 37%
• Nitrogen – 0 – 2.7%

Peat

Peat is used today in many areas of life. This includes agriculture, livestock farming, biochemistry, medicine, and energy. Peat not only improves the structure of the soil, but also improves its water and air properties. Peat contains less harmful impurities and sulfur. Peat has a carbon content of 50% - 60%.

Brown coal

Brown coal is a dense earthy mass formed from peat, with a well-preserved woody structure. It burns easily with a smoky flame, releasing an unpleasant odor. Total world reserves of brown coal are approximately 4.9 trillion tons. The main reserves are located in Russia, Germany, Poland, and the Czech Republic. Brown coal is used much less than hard coal. During dry distillation of brown coal, ammonia is formed with acetic acid. Dry distillation also produces paraffin, buttons, bracelets and some other small items. The youngest of the fossil coals is brown coal. Composition of brown coal:

• 50% - 77% - carbon,
• 26% - 37% oxygen,
• 0 - 2% - nitrogen,
• 3% – 5% - hydrogen.

Modern technologies make it possible today to produce synthetic gas from brown coal, which is an alternative to fuel oil.

Coal

Hard coal is one of the types of fossil fuels, a transitional state from brown coal to anthracite. There is more coal being developed than any other, approximately 2.5 billion tons per year, which is approximately 700 kg for every inhabitant of our Earth. Coal is used to generate electricity in thermal power plants, as fuel in private homes, factories, and much more. Hard coal burns with a luminous flame and has a higher heat of combustion than brown coal.

Coal contains moisture from 3% to 12%, and also contains up to 32% volatile flammable substances.

The chemical composition of coal includes:

• carbon from 75% to 93% (depending on variety, location),
• hydrogen from 4% to 6%,
• oxygen from 3% to 19%
• nitrogen up to 2.7%

Anthracite

Anthracite is characterized by high density, shine, has the highest heat of combustion, but does not ignite well. They are used in particular for the manufacture of carbon electrodes and electrode mass. It is used as a raw material in metallurgy. Anthracite occurs mainly at depths of 6 kilometers.

It has the highest carbon content 95% - 97%, hydrogen - 1% - 3%.

Activated carbon

Activated carbon is a substance with a porous structure, obtained from various carbon-containing materials of organic origin, which include charcoal, petroleum coke, coal coke, coconut shells, walnuts, olive kernels, and apricots. The best activated carbon is carbolene, made from coconut shells; it can be regenerated many times.

The composition of activated carbon includes 87%-97% carbon, also contains hydrogen, nitrogen, oxygen, and does not contain impurities. Chemical composition activated carbon is similar to graphite used in pencils and diamond.

Activated carbon is divided into classes:

• by type of raw material (wood, coconut, coal, etc.),
• by activation method (steam or thermochemical),
• by release form (powder, granules, molded, fabric impregnated with active carbon)
• by purpose (clarification, gas, recovery, catalysts).

Application of activated carbon

Activated carbon is widely used in many areas of life and industry:

• water purification from xenobiotics, dioxins,
• in the food industry (in the production of alcohol, carbonated drinks, deodorization and clarification of fats and oils, etc.)
• in the oil and gas production, chemical, processing industries,
• in environmental activities (purification of industrial wastewater, liquidation of oil and petroleum product spills, flue gas purification, etc.)
• in the metallurgical, mining industry,
• in the fuel and energy industry,
• in the nuclear industry,
• in medicine (cleansing the body of toxins),
• in the pharmaceutical industry (charcoal tablets, blood substitutes, antibiotics, etc.),
• in the production of personal protective equipment (respirators, gas masks),
• for water purification in swimming pools and aquariums.

DEFINITION

Coal- one of the allotropic modifications of the chemical element carbon.

The structure of the carbon atom is shown in Fig. 1. In addition to charcoal, carbon can exist in the form of a simple substance: diamond or graphite, belonging to the hexagonal and cubic systems, coke, soot, carbyne, polycumulene graphene, fullerene, nanotubes, nanofibers, astralen, etc.

Rice. 1. Structure of the carbon atom.

Chemical formula of coal

Chemical formula of coal- C. It shows that the molecule of this substance contains one carbon atom (Ar = 12 amu). Using the chemical formula, you can calculate the molecular weight of coal:

M(C) = M r (C) × 1 mol = 12.0116 g/mol

Structural (graphic) formula of coal

More obvious is structural (graphical) formula of coal. It shows how atoms are connected to each other inside a molecule (Fig. 2).

Rice. 2. Structure of allotropic modifications of carbon: a) diamond; b - graphite; c) - fullerene.

Electronic formula

Electronic formula, showing the distribution of electrons in an atom by energy sublevel is shown below:

6 C 1s 2 2s 2 2p 2

It also shows that carbon belongs to the elements of the p-family, as well as the number of valence electrons - there are 4 electrons in the outer energy level (2s 2 2p 2).

Examples of problem solving

EXAMPLE 1

Exercise	The mass fraction of chlorine in phosphorus chloride is 77.5%. Determine the simplest formula of the compound.
Solution	Let's calculate the mass fraction of phosphorus in the compound: ω(P) = 100% - ω(Cl) = 100% - 77.5% = 22.5% Let us denote the number of moles of elements included in the compound as “x” (phosphorus) and “y” (chlorine). Then, the molar ratio will look like this (relative values atomic masses, taken from the Periodic Table by D.I. Mendeleev, round to whole numbers): x:y = ω(P)/Ar(P) : ω(Cl)/Ar(Cl); x:y= 22.5/31: 77.5/35.5; x:y= 0.726: 2.183 = 1: 3 This means that the formula for combining phosphorus with chlorine will be PCl 3. This is phosphorus(III) chloride.
Answer	PCl 3

EXAMPLE 2

Exercise	Determine the simplest formula for the compound of potassium with manganese and oxygen, if the mass fraction of potassium is 24.7%, manganese 34.8%.
Solution	The mass fraction of element X in a molecule of the composition NX is calculated using the following formula: ω (X) = n × Ar (X) / M (HX) × 100% Let's calculate the mass fraction of oxygen in the compound: ω (P) = 100% - ω(K) - ω(Mn) = 100% - 24.7% - 34.8% = 40.5% Let us denote the number of moles of elements included in the compound as “x” (potassium), “y” (manganese) and “z” (oxygen). Then, the molar ratio will look like this (the values ​​of relative atomic masses taken from D.I. Mendeleev’s Periodic Table are rounded to whole numbers): x:y:z = ω(K)/Ar(K) : ω(Mn)/Ar(Mn) : ω(O)/Ar(O); x:y:z= 24.7/39: 34.8/55: 40.5/16; x:y:z= 0.63:0.63:2.53 = 1: 1: 4 This means that the formula for the compound of potassium, manganese and oxygen will be KMnO 4 . This is potassium permanganate.
Answer	KMnO4