1. Chemical properties of coal
2. Classification of hard coal
3. Formation of hard coal
4. Reserves of coal
Coal is sedimentary rock, which is a deep decomposition of plant remains (tree ferns, horsetails and club mosses, as well as the first gymnosperms).
Chemical properties of hard coal
By chemical composition coal is a mixture of high-molecular aromatic compounds with a high mass fraction of carbon, as well as water and volatile substances with small amounts of mineral impurities. These impurities form ash when coal is burned. Fossil coals differ from each other in the ratio of their components, which determines their heat of combustion. A number of organic compounds that make up coal have carcinogenic properties.
Most deposits of coal were formed in the Paleozoic, mainly in the Carboniferous period, about 300-350 million years ago. By chemical composition coal 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 coal is burned. Fossil coals differ from each other in the ratio of their components, which determines their heat of combustion. A number of organic compounds that make up coal have carcinogenic properties. The carbon content in hard coal, depending on its grade, 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 higher calorific value, calculated on the wet ash-free mass of hard 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 access. Therefore, they could not release the carbon taken from it into the atmosphere. The access of air stopped especially sharply where swamps and swampy forests descended as a result of tectonic movements and changes in climatic conditions and were covered from above 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, coal, anthracite and graphite.
According to the composition of the main component - organic matter, coals are divided into three genetic groups: humolites, sapropelites, saprohumolites. Humolites predominate, the source material of which was the remains of higher terrestrial plants. Their deposition occurred mainly in swamps that occupied the low-lying coast of the seas, bays, lagoons, and freshwater basins. As a result of biochemical decomposition, the accumulated plant material was processed into peat, while water content and the chemical composition of the aquatic environment had a significant effect. The carbon content of hard coal ranges from 75 to 90 percent. The exact composition is determined by the location and conditions of coal conversion. Mineral impurities are either in a finely dispersed state in the organic mass, or in the form of the thinnest 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 neoplasms that precipitate from solutions of water circulating in peat bogs, etc.
As a result of prolonged exposure to elevated temperatures and pressure, brown coals are converted into bituminous coals, and the latter into anthracites. 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.
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 oxygen content, and the release of volatile substances; the hydrogen content, combustion heat, hardness, density, brittleness, optics, electricality, and other physical properties change. Coals in the middle stages of metamorphism acquire sintering properties - the ability of gelified and lipoid components of organic matter to pass, 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 its effect on the chemical composition and physical properties, oxidation has the opposite direction compared to metamorphism:
coal loses its strength properties and sintering properties;
the relative content of oxygen in it increases, the amount of carbon decreases, the humidity and ash content increase, and the calorific value sharply decreases.
The depth of oxidation of fossil coals, depending on the modern and ancient relief, 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, the calorific value is 35,000 kJ / kg. Coal is considered suitable for technological use if after combustion the ash 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 iron. Since the 19th century, a major purchaser of coal has been transport. The main directions of the industrial use of coal: the production of electricity, metallurgical coke, combustion for energy purposes, obtaining various (up to 300 items) products during chemical processing. The consumption of coals for the production of high-carbon carbon-graphite structural materials, mountain wax, plastics, synthetic, liquid and gaseous high-calorie fuels, aromatic products by hydrogenation, and highly nitrous acids for fertilizers is increasing. Coke obtained from coal is needed 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. In this case, coke is obtained - a porous solid substance. In addition to coke, during the dry distillation of coal, volatile products are also formed, when they are cooled to 25-75 ° C, coal tar, ammonia water and gaseous products are formed. 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). This is naphthalene and its homologues
anthracene oil - anthracene, fenathrene, etc.
The composition of gaseous products (coke oven gas) includes benzene, toluene, xyols, phenol, ammonia and other substances. Crude benzene is extracted from coke oven gas after purification from ammonia, hydrogen sulfide and cyanide compounds, 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 an important role in modern life as sources of various types of energy. When coal is burned, heat is released that is used for heating, cooking, and for many industrial processes. Most of the heat received is converted into other forms of energy and spent on 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 higher calorific value calculated for the wet ashless mass of hard coal is not less than 238 MJ/kg.
Coal is formed from the decomposition products of organic matter of higher plants that have undergone changes under the pressure 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 calorific value 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;
refractive index of light - 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; Ruhr - in the Republic of Germany; Big Yellow River - in China; South Wales - in England; Valenciennes - in France, etc.
The use of coal is varied. It is used as household, energy fuel, for metallurgical and chemical industry, as well as for extracting rare and trace elements from it. Coal, coking, heavy industries carry out the processing of coal by coking. Coking is an industrial method of coal processing by heating up to 950-1050 C without air access. The main coke-chemical products are: coke oven gas, crude benzene, coal tar, ammonia.
Hydrocarbons are recovered from coke oven gas by washing in scrubbers with liquid absorption oils. After distillation from oil, distillation from a fraction, purification and re-rectification, pure commercial products are obtained, such as: benzene, toluene, xylenes, etc. From 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. A promising raw material is also cyclopentadiene, which is also obtained from coal. Coal - raw material to obtain naphthalene and other individual aromatic hydrocarbons. The most important products of processing are pyridine bases and phenols.
By processing, in total, more than 400 different products can be obtained, the cost of which, in comparison with cost coal itself, increases by 20-25 times, and by-products obtained at coke plants exceed price the coke itself.
Very promising is the combustion (hydrogenation) of coal with the formation of liquid fuel. For the production of 1 ton of black gold, 2-3 tons of coal are consumed. Artificial graphite is obtained from coal. They are used as inorganic raw materials. When processing 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. For the purpose of optimal use of coal, it is enriched (removal of mineral impurities).
Coal contains up to 97% of carbon; it can be said that it underlies all hydrocarbons, i.e. they are based on carbon atoms. Often one encounters amorphous carbon in the form of coal. By structure, amorphous carbon is the same graphite, but in a state of the finest grinding. The practical application of amorphous forms of carbon is varied. Coke and coal - as a reducing agent in metallurgy during iron smelting.
Coal classification
Coal is formed from the decomposition products of the organic remains of higher plants that have undergone changes (metamorphism) under the pressure of 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. On the change in these qualities, determined by the results of the thermal decomposition of coal (the yield of volatile substances, the characteristic of the non-volatile residue), the industrial classification adopted in the USSR is built.
Coal grades:
long-flame (D),
gas (G),
gas fatty (GZH),
fatty (F),
coke fatty (QOL),
coke (K),
lean sintering (OS),
skinny (T),
weakly caking (SS),
semi-anthracites (PA)
anthracites (A).
Sometimes anthracites stand out in a separate group. For coking, mainly coal grades G, Zh, K and OS, and partially D and T are used. .5-5.0% for grades T-A; decrease in the content (in the combustible mass) of oxygen from 15% to 1.5%; hydrogen - from 5.7% to 1.5%; content sulfur, nitrogen and ash does not depend on belonging to a particular brand. The calorific value of the combustible mass coal increases sequentially 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 grades PA and A.
According to the size of the pieces obtained during mining, hard coal is classified into:
slab (P) - more than 100 mm,
large (K) - 50-100 mm,
walnut (O) - 26-50 mm,
small (M) - 13-25 mm,
seed (C) - 6-13 mm,
shtyb (W) - less than 6 mm,
ordinary (P) - not limited in size.
Belonging to the brand and the size of pieces of coal are indicated by letter combinations - DK, etc.
Approximately on the same principles as in the USSR, coal classifications are built in a number of Western European countries. AT USA the most common classification is coal, based on the yield of volatile substances and the heat of combustion, according to which they are divided into sub-bituminous with a high yield of volatile substances (corresponds to Soviet grades D and G), bituminous with an average yield of volatile substances (corresponds to grades PZh and K), bituminous with a low yield of volatile substances (OS and T) and anthracite coals, divided into semianthracites (partially T and A), anthracites proper and metaanthracites (A). In addition, there is an international classification of coal, based on the content of volatile substances, caking, coking and displaying the technological properties of coals.
Formation of hard coal
The formation of coal is characteristic of all geological systems, starting 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 seams of various thicknesses (from fractions of m to several tens or more m). The depth of occurrence of coal is different - from the exit to the surface to 2000-2500 m and deeper. With the modern level of mining technology, the extraction of hard coal can be carried out in an open way to a depth of 350 m.
For the formation of coal, abundant accumulation of plant mass is necessary. In ancient peat bogs, starting from the Devonian period, organic matter accumulated, from which, without access to oxygen, fossil coals were formed. Most commercial fossil coal deposits date from this period, although younger deposits also exist. The age of the most ancient coals is estimated at about 350 million years.
Coal is formed when rotting plant material accumulates faster than it can be bacterially decomposed. The ideal environment for this is created in swamps, where stagnant water, depleted of oxygen, prevents the vital activity of bacteria and thereby protects the plant mass from complete destruction. At a certain stage process the acids released during it prevent the further activity of bacteria. This is how peat arises - the original product to form coal. If then it is buried under other deposits, then the peat experiences compression and, losing water and gases, is converted into coal.
Under the pressure of a thickness of sediments with a thickness of 1 kilometer, a layer of brown coal 4 meters thick is obtained from a 20-meter layer of peat. If the depth of burial of plant material reaches 3 kilometers, then the same layer of peat will turn into a layer of coal 2 meters thick. At a greater depth, about 6 kilometers, and at a higher temperature, 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. The development is carried out in an open way, if the depth of the coal seam does not exceed 100 meters. There are also frequent cases when, with an ever greater deepening of a coal pit, it is further advantageous to develop a coal deposit by an 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.
Along with coal, coal-bearing deposits contain many types of georesources that have consumer significance. These include host rocks such as raw material 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
The general geological reserves of hard coal in the USSR are about 4,700 billion tons (according to estimates in 1968), including grades (in billion tons): D - 1,719; D-G - 331; G - 475; GZh - 69.4; W - 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 in the Tunguska basin. The largest coal basins being developed in the USSR are Donetsk, Kuznetsk, Pechora, Karaganda; in USA- Appalachian and Pennsylvanian, in Poland - Upper Silesian and its continuation in Czechoslovakia - Ostrava-Karvinsky, in Germany— Ruhr, in China— Big Juanhabass, in England— South Wales, in France- Valenciennes and in Belgium - Brabant. The use of coal is varied.
It is used as a household, energy fuel, raw material for the metallurgical and chemical industries, as well as for the extraction of rare and trace elements from it.
For two decades in a row, coal has been in the shadow of the oil boom. Mountains of unmarketable coal grew into the sky. Numerous mines were closed, hundreds of thousands of miners lost theirs. The Appalachian region of the United States, once a flourishing coalfield, has become one of the darkest disaster areas. A disorderly, monopolist-driven transition to cheap, imported - mostly from the Middle East - oil doomed coal to the role of "Cinderella", devoid 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 dispersed throughout the world. Most industrial countries they are not spared. The land is surrounded by two rich coal zones. One stretches 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 coal are located in the countries of the former USSR, the USA and China. Hard coal dominates western Europe. The main coal basins in Eurasia: South Wales, Valenciennes Liege, Saar-Lotharga, Ruhr, Asturias, Kizelovsky, Donetsk, Taimyr, Tunguska, South Yakutia, Funshunsky; in Africa: Jerada, Abadla, Enugu, Huanki, 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 flaming continent: Carare, Junin, Santa Catarina, Concepción. In Ukraine, the Lvov-Volyn basin and the Donbass rich in deposits should be noted.
Sources
bse.sci-lib.com/ Great Soviet Encyclopedia
en.wikipedia.org Wikipedia - the free encyclopedia
www.bankreferatov.ru abstracts
dic.academic.ru Dictionaries and encyclopedias at Academician
geography.kz Geography
www.bibliotekar.ru Librarian
poddoni.com/ PalletEck
Encyclopedia of the investor. 2013 .
Synonyms:See what "Coal" is in other dictionaries:
Coal- Coal Coal was the first fossil fuel used by man. He enabled the industrial revolution, which in turn helped develop the coal industry by providing it with more modern technology. In 1960 ... ... Wikipedia
Since ancient times, mankind has been using coal as one of the sources of energy. And today this mineral is used quite widely. Sometimes it is called solar energy, which is preserved in stone.
Application
Coal is burned to produce heat that is used for hot water and home heating. The mineral is used in the technological processes of metal smelting. Thermal power plants convert coal into electricity by burning it.
Scientific advances have made it possible to use this valuable substance in a different way. Thus, the chemical industry has successfully mastered a technology that makes it possible to obtain liquid fuel from coal, as well as such rare metals as germanium and gallium. From a valuable fossil, carbon-graphite with a high carbon concentration is currently being extracted. Methods have also been developed for producing plastics and high-calorie gaseous fuels from coal.
A very low fraction of low-grade coal and its dust are pressed into briquettes after processing. This material is great for heating private houses and industrial premises. In general, more than four hundred items of various products are produced after chemical processing, which coal is subjected to. The price of all these products is ten times higher than the cost of raw materials.
Over the past few centuries, mankind has been actively using coal as a fuel necessary for obtaining and converting energy. Moreover, the need for this valuable mineral has been increasing in recent years. This is facilitated by the development of the chemical industry, as well as the need for valuable and rare elements obtained from it. In this regard, intensive exploration of new deposits is underway in Russia today, mines and quarries are being created, enterprises are being built to process this valuable raw material.
Fossil origin
In ancient times, the Earth had a warm and humid climate, in which a variety of vegetation flourished. From it coal was later formed. The origin of this fossil lies in the accumulation of billions of tons of dead vegetation at the bottom of the swamps, where they were covered with sediment. About 300 million years have passed since then. Under the powerful pressure of sand, water and various rocks, vegetation slowly decomposed in an oxygen-free environment. Under the influence of high temperatures, which were given by the closely located magma, this mass solidified, which gradually turned into coal. The origin of all existing deposits has only such an explanation.
Mineral reserves and its extraction
There are large deposits of coal on our planet. In total, according to experts, the earth's bowels store fifteen trillion tons of this mineral. Moreover, the extraction of coal in terms of its volume is in the first place. It is 2.6 billion tons per year, or 0.7 tons per inhabitant of our planet.
Coal deposits in Russia are located in various regions. Moreover, in each of them, the mineral has different characteristics and has its own depth of occurrence. Below is a list that includes the largest coal deposits in Russia:
- It is located in the southeastern part of Yakutia. The depth of coal in these places allows for open-pit mining. This does not require special costs, which affects the reduction in the cost of the final product.
- Tuva deposit. According to experts, there are about 20 billion tons of minerals on its territory. The field is very attractive for development. The fact is that eighty percent of its deposits are located in one layer, which has a thickness of 6-7 meters.
- Minusinsk deposits. They are located in the Republic of Khakassia. These are several deposits, the largest of which are Chernogorskoye and Izykhskoye. Pool stocks are small. According to experts, they range from 2 to 7 billion tons. Coal, which is very valuable in terms of its characteristics, is mined here. The properties of the mineral are such that when it is burned, a very high temperature is recorded.
- This deposit, located in the west of Siberia, gives a product used in ferrous metallurgy. The coal that is mined in these places goes for coking. The volume of deposits here is simply huge.
- This deposit gives a product of the highest quality. The greatest depth of mineral deposits reaches five hundred meters. Mining is carried out both in open cuts and in mines.
Hard coal in Russia is mined in the Pechora coal basin. Deposits are also being actively developed in the Rostov region.
The choice of coal for the production process
In various industries, there is a need for different grades of minerals. What are the differences between hard coal? The properties and quality characteristics of this product vary widely.
This happens even if the coal has the same marking. The fact is that the characteristics of a fossil depend on the place of its extraction. That is why each enterprise, choosing coal for its production, should familiarize itself with its physical characteristics.
Properties
Coal differs in the following properties:
Degree of enrichment
Depending on the purpose of use, various hard coal can be purchased. In this case, the properties of the fuel become clear, based on the degree of its enrichment. Allocate:
1. Concentrates. Such fuel is used in the production of electricity and heat.
2. Industrial products. They are used in metallurgy.
3. fine fraction of coal (up to six millimeters), as well as dust resulting from rock crushing. Briquettes are formed from the sludge, which have good performance properties for household solid fuel boilers.
Degree of coalification
According to this indicator, there are:
1. Brown coal. This is the same coal, only partially formed. Its properties are somewhat worse than those of higher quality fuel. Brown coal produces low heat during combustion and crumbles during transportation. In addition, it has a tendency to spontaneous combustion.
2. Coal. This type of fuel has a large number of grades (brands), the properties of which are different. It is widely used in energy and metallurgy, housing and communal services and the chemical industry.
3. Anthracites. This is the highest quality type of coal.
The properties of all these forms of minerals differ significantly from each other. So, brown coal is characterized by the lowest calorific value, and anthracites are the highest. What is the best coal to buy? The price must be economically feasible. Based on this, the cost and specific heat are in the optimal ratio for ordinary coal (within $ 220 per ton).
Size classification
When choosing coal, it is important to know its dimensions. This indicator is encrypted in the grade of the mineral. So, coal happens:
- "P" - slab, which is large pieces over 10 cm.
- "K" - large, the size of which is from 5 to 10 cm.
- "O" - a nut, it is also quite large, with fragment sizes from 2.5 to 5 cm.
- "M" - small, with small pieces of 1.3-2.5 cm.
- "C" - a seed - a cheap fraction for long-term smoldering with dimensions of 0.6-1.3 cm.
- "Sh" - shtyb, which is mostly coal dust, intended for briquetting.
- "P" - ordinary, or non-standard, in which there may be fractions of various sizes.
Brown coal properties
This is the lowest quality coal. Its price is the lowest (about one hundred dollars per ton). formed in ancient swamps by pressing peat at a depth of about 0.9 km. This is the cheapest fuel containing a large amount of water (about 40%).
In addition, brown coal has a rather low heat of combustion. It contains a large amount (up to 50%) of volatile gases. If you use brown coal for the furnace, then in terms of its quality characteristics it will resemble raw firewood. The product burns heavily, smokes heavily and leaves behind a large amount of ash. Briquettes are often prepared from this raw material. They have good performance characteristics. Their price is in the range of eight to ten thousand rubles per ton.
Properties of hard coal
This fuel is of better quality. Coal is a rock that is black in color and has a matte, semi-gloss or shiny surface.
This type of fuel contains only five to six percent moisture, which is why it has a high calorific value. Compared to oak, alder and birch firewood, coal gives 3.5 times more heat. The disadvantage of this type of fuel is its high ash content. The price of coal in summer and autumn ranges from 3900 to 4600 rubles per ton. In winter, the cost of this fuel increases by twenty to thirty percent.
Coal storage
If the fuel is supposed to be used for a long period, then it must be placed in a special shed or bunker. There it must be protected from direct sunlight and rain.
If the heaps of coal are large, then during storage it is necessary to constantly monitor their condition. Fine fractions in combination with high temperature and moisture can ignite spontaneously.
/ Rock Coal
Coal refers to sedimentary rock formed in the earth's layers. This is one of the most ancient types of fuel used by people tens of thousands of years ago. Coal is formed in places where trees and other plants accumulate in one place, after which this large plant mass does not have time to completely decompose. An ideal place for this is an oxygen-poor swamp area. The main part of the modern reserves of this mineral was formed about three hundred million years ago in the Paleozoic era. The composition of this fossil and its appearance depends on the age and depth of occurrence. Anthracite can be attributed to the most ancient rock, the deposits of which are found at a depth of up to 5 km. It has a lot of carbon, a minimum of moisture and the highest (up to 7400 kcal / kg) calorific value. Coal is in the middle of the classification. Its deposits are found at a depth of up to 3 km. It contains about 12% water, 32% volatile matter and 75 to 95% carbon. It is easily flammable, burns well and due to the minimum amount of moisture it gives a sufficient amount of heat. Brown coal belongs to the youngest species of this breed. Its deposits can be found at a depth of up to 1000 meters. It contains more than 40% water, and a lot of volatile substances. It is highly flammable, burns well, but gives little heat. Today, there are about 3,700 coal basins worldwide, covering about 15 percent of the entire land area. Almost ¼ of the world's deposits of this natural resource is located in the United States, Russia is in second place, and its deposits occupy 13% of the world's. In third place is China with 11 percent. The largest Russian basin is the Kuznetsk, located in the Kemerovo region, with reserves of about 640 billion tons. The method of extraction depends on the depth of the coal. It can be open when the solid layer of rock above the coal explodes, or closed. Coal is a widely used type of mineral found deep underground. Coal was formed many millions of years ago, due to the gradual hardening of animal and plant remains in conditions with a minimum oxygen content (underground). It is mined manually and semi-mechanized in deep underground coal mines. In addition to the use of coal as a fuel, it is used in the national economy and everyday life: In total, more than four hundred industrial products are obtained in the process of chemical processing of coal. The quality of coal is determined by the percentage of impurities in it. The greater the amount of impurities, the worse the quality of coal. Foreign impurities are non-combustible substances that, after the combustion of coal, remain in the form of slag. Depending on the territory of occurrence of coal deposits, the percentage of minerals in it is very different. The quality of coal is determined by the percentage of moisture content, minerals, ash compounds and sulfur in it. Sulfur is one of the most unfavorable foreign impurities. When coal with a high percentage of sulfur compounds is burned, a large amount of sulfuric acids is released into the atmosphere. This eventually leads to acid rain, which destroys vegetation. Coal, the percentage of sulfur in which is more than 4-8%, is unsuitable for use in the heat and power sector.How is it formed
Types of coal and its composition
Coal deposits
How is it obtained
Where is used
What are the criteria for determining the quality of coal
report an error in the description
Rock properties
Catalog of Minerals
Related Articles
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This material is formed by the decomposition of plant remains, and the reserves of coal that are mined today are about 350 million years old, and they were formed back in the Paleozoic period.
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The variety of applied and known methods and means of destruction of coals is due, as can be seen from the history of their development, the variety of properties of coals and the natural conditions of their occurrence, as well as the underground conditions in which mining takes place.
Coal- this is a solid, exhaustible, non-renewable mineral that a person uses to obtain heat by burning it. According to the classification, it belongs to sedimentary rocks.
What it is?
Coal as a source of energy, people began to use in antiquity along with firewood. The “flammable stone” was found on the surface of the earth, later it was purposefully mined from under it.
Coal appeared on Earth about 300-350 million years ago, when tree-like ferns flourished on primeval swamps and the first gymnosperms began to appear. Huge trunks fell into the water, gradually forming thick layers of undecomposed organic mass. Wood with limited access to oxygen did not rot, but gradually sank deeper and deeper under its weight. Over time, due to the displacement of the layers of the earth's crust, these layers sank to a considerable depth, and there, under the influence of great pressure and elevated temperature, a qualitative change took place in wood into coal.
Types of coal
Today, various types of coal are mined.
- Anthracites are the hardest grades with great depth and maximum combustion temperature.
- Coal - many varieties mined in mines and open pit. It is widely used in many areas of human activity.
- Brown coal - formed from the remains of peat, the youngest type of coal. It has the lowest combustion temperature.
All types of coal lie in layers and their locations are called coal basins.
Coal mining
At first, coal was simply collected at the places where the seam came to the surface. This could have happened as a result of the displacement of the layers of the earth's crust.
Often, after landslides in mountainous areas, such outcrops of the deposit were exposed, and people got the opportunity to get to pieces of “combustible stone”.
Later, when primitive technology appeared, coal began to be developed in an open way. Some coal mines plunged to a depth of more than 300 meters.
Today, thanks to the availability of sophisticated modern technology, people descend underground into mines more than a kilometer deep. From these horizons, the highest quality and valuable coal is mined.
Where is coal used?
All types of coal can be used to generate heat. When burned, it releases much more than can be obtained from wood or other solid fuels. The hottest grades of coal are used in metallurgy, where high temperatures are needed.
In addition, coal is a valuable raw material for the chemical industry. A lot of necessary and useful substances are extracted from it.
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Borodino coal mine. Krasnoyarsk region
Officially, these are layers of biomass accumulation from forests and plants, coked under other layers. Or it was powerful ancient peat bogs (lower thickest layer).
This pattern of coal layers is ubiquitous:
Nazarovsky coal mine. Two thin layers close to the surface
The main layer with brown coal does not look like a random mass with petrified trunks of ancient trees chaotically laid. The reservoir has clear strata - many layers. That is, the official version with ancient trees is not suitable. And it is not suitable yet because of the high sulfur content in brown coal seams.
Table of content of some chemical elements in coals, peat, wood and oil.
In order not to think about the meaning of the table, I will write the conclusions from it.
1. Carbon. In wood, it is the least of the listed fuel sources. And it is not clear (if we take into account the traditional version of coal formation) why the amount of carbon increases with the accumulation of organic matter (wood or peat) in the layers. A contradiction that no one explains.
2. Nitrogen and oxygen. Nitrogen compounds are one of the building blocks of wood and vegetation. And why the amount of nitrogen decreased after the transformation of wood or peat into brown coal is again not clear. Again a contradiction.
3. Sulfur. In wood there is no amount sufficient for the accumulation of this chemical element. Even in peat, sulfur is negligible compared to the layers of brown and hard coal. Where does sulfur get into the layers? The only assumption is that there was sulfur in the layers from the very beginning. Mixed with organic? But somehow, the concentration of sulfur in coals coincides with the sulfur content in oil.
Usually sulfur is pyrite, sulfate and organic. As a rule, pyrite sulfur prevails. The sulfur contained in coals is usually in the form of magnesium, calcium and iron sulfates, iron pyrite (pyritic sulfur) and in the form of organic sulfur-containing compounds. Separately determine, as a rule, only sulfate and sulfide sulfur; organic is defined as the difference between the amount of total sulfur in coal and the sum of sulfate and sulfide sulfur.
Sulfur pyrite is an almost constant companion of coal and, moreover, sometimes in such quantity that it makes it unfit for consumption (for example, coal from the Moscow basin).
According to these data, it turns out that the accumulation of organic matter (wood or peat) is not related to coal. The formation of brown coal is an abiogenic process. But what? Why are brown coals located relatively shallow, while coal can be located at depths of up to two kilometers?
The next question is: where are all the fossils of flora and fauna in brown coal seams. They must be massive! Trunks, plants, skeletons and bones of dead animals - where are they?
Leave imprints are found only in overburden rocks:
Petrified fern. Such petrified plants come across during coal mining. This specimen was mined while working at the Rodinskaya mine in the Donbass. But we will return to these alleged fossils below.
This refers to the waste rock of coal mines. I didn't find anything on brown coal.
Areas of coal formation. Most of the coal is found in the northern hemisphere, absent from the equator and the tropics. But there is the most acceptable climate for the accumulation of organic matter in antiquity. There are also no areas (in latitudinal form) of accumulation on the old equators. This distribution is clearly related to another reason.
One more question. Why was this useful fossil fuel not used in antiquity? There are no mass descriptions of the extraction and use of brown coal. The first mention of coal refers only to the time of Peter I. It is not at all difficult to get (get to the bottom of the seam). This is done in an artisanal way by local residents in Ukraine:
There are also more large-scale open pit coal mining:
Coal under 8-10 meters of clay. For the formation of coal, geologists say you need a lot of pressure and temperature. It was clearly not here.
Coal is soft and crumbles.
When digging wells, they had to stumble upon the layers and find out that they were burning. But history tells us about the beginning of mass coal mining only in the 19th century.
Or maybe these layers did not exist until the 19th century? As it was not in the middle of the 19th century. trees! See the desert landscapes of the Crimea and photographs of Stolypin settlers who climbed into the remote corners of Siberia in wagon trains. And now there is an impenetrable taiga. This is me about the 19th century version of the flood. Its mechanism is not clear (if it did exist). But back to brown coals.
What breed do you think it is? Brown coal? Looks like it, but guess not. These are bituminous sands.
Large-scale oil production from tar sands in Canada. Before the fall in oil prices, it was a cost-effective, even profitable business. On average, out of four tons of bitumen, only one barrel of oil is produced.
If you do not know, then you will not think that oil is being produced here. It looks like a brown cut.
Another example from Ukraine:
In the village of Starunya (Ivano-Frankivsk region), oil comes to the surface by itself, creating small volcanoes. Some oil volcanoes are on fire!
Then it will all petrify and there will be a coal seam.
So what am I getting at? To the fact that oil during the cataclysm, the break of the earth came out, spilled. But not petrified in the sands. And brown coal, perhaps, is the same, but in Cretaceous or other deposits. There, the fraction before oil was less than sand. The stony state of the coals says that it is involved in the chalk layers. Perhaps some reactions took place and the layers turned into stone.
Even Wikipedia says:
Fossil coal is a mineral, a type of fuel, formed both from parts of ancient plants, and to a large extent from bituminous masses that poured onto the surface of the planet, metamorphosed due to sinking to great depths underground at high temperatures and without oxygen.
But the version of the abiogenic origin of brown coal from oil spills is not developed anywhere else.
Some write that this version does not explain the many layers of brown coal. If we take into account that not only masses of oil, but also water-mud sources came to the surface, then alternation is quite possible. Oil and bitumen are lighter than water - they floated on the surface and were deposited and adsorbed on the rock in the form of thin layers. Here is an example in a seismically active zone in Japan:
Water comes out of cracks. Of course, it is not deep, but what prevents the waters of artesian springs or underground oceans from coming out during larger processes and throwing masses of rocks milled into clay, sand, lime, salt, etc. to the surface when they come out. Set aside strata in a short period, not millions of years. I am more and more inclined that in some places at certain times the flood could be caused not by the passage of a wave from the ocean, but by the release of water and mud masses from the bowels of the Earth.
Sources:
http://sibved.livejournal.com/200768.html
https://new.vk.com/feed?w=wall178628732_2011
http://forum.gp.dn.ua/viewtopic.php?f=33&t=2210
http://chispa1707.livejournal.com/1698628.html
A separate issue is the formation of coal
Commentary in one of the articles from jonny3747
:
Coal in the Donbass is most likely the displacement of plates one under the other, along with all the forests, ferns, etc. He himself worked at depths of more than 1 km. The layers lie at an angle, as if one plate crawled under another. Between the layer of coal and the rock, there are very often imprints of plants, quite a lot caught my eye. And what is interesting between solid rock and coal there is a thin layer, as it were, not of rock but still not of coal, crumbles in the hands, unlike the rock, it has a dark color and it was in it that there were often prints.
This observation fits very well with the process of pyrographite growth in these layers. Most likely, the author saw such:
Remembering the fern fossils in the photos above
Here are excerpts from the monograph "Unknown Hydrogen" and the work "History of the Earth without the Carboniferous Period":
Based on their own research and a number of works of other scientists, the authors state:
“Given the recognized role of deep gases, ... the genetic relationship of natural carbonaceous substances with juvenile hydrogen-methane fluid can be described as follows.
1. From the gas-phase system C-O-H (methane, hydrogen, carbon dioxide) ... carbonaceous substances can be synthesized - both in artificial conditions and in nature ...
5. Pyrolysis of methane diluted with carbon dioxide under artificial conditions leads to the synthesis of liquid ... hydrocarbons, and in nature - to the formation of the entire genetic series of bituminous substances.
CH4 → Sgraphite + 2H2
In the process of methane decomposition in depth, the formation of complex hydrocarbons occurs in a completely natural way! It happens because it turns out to be energetically favorable! And not only gaseous or liquid hydrocarbons, but also solid ones!
Methane and now constantly "oozes" in places of extraction of coal. It may be residual. Or it may be evidence of the continuation of the process of hydrocarbon vapors coming from the bowels.
Well, now it's time to deal with the "trump card" of the version of the organic origin of brown and hard coal - the presence of "carbonized plant residues" in them.
Such "carbonized plant residues" are found in coal deposits in huge quantities. Paleobotanists "confidently identify plant species" in these "remains".
It was on the basis of the abundance of these "remnants" that the conclusion was made about almost tropical conditions in the vast regions of our planet and the conclusion about the violent flowering of the plant world in the Carboniferous period.
But! When pyrolytic graphite was obtained by pyrolysis of methane diluted with hydrogen, it was found that, away from the gas flow, dendritic forms are formed in stagnant zones, very similar to "plant residues".
Samples of pyrolytic graphite with "plant patterns" (from the monograph "Unknown Hydrogen")
The simplest conclusion that follows from the above photographs of "carbonized plant forms", which in fact are only forms of pyrolytic graphite, will be this: paleobotanists now need to think hard! ..
And the scientific world continues to write dissertations on the origin of coals based on the biological accumulation of layers
1. Hydride compounds in the bowels of our planet decompose when heated (see the author’s article “Does the fate of Phaeton await the Earth? ..”), releasing hydrogen, which, in full accordance with the law of Archimedes, rushes up - to the surface of the Earth.
2. On its way, due to its high chemical activity, hydrogen interacts with the substance of the interior, forming various compounds. Including such gaseous substances as methane CH4, hydrogen sulfide H2S, ammonia NH3, water vapor H2O and the like.
3. Under conditions of high temperatures and in the presence of other gases that are part of the fluids of the subsoil, a stepwise decomposition of methane occurs, which, in full accordance with the laws of physical chemistry, leads to the formation of gaseous hydrocarbons, including complex ones.
4. Rising both along the existing cracks and faults in the earth's crust, and forming new ones under pressure, these hydrocarbons fill all the cavities available to them in geological rocks. And due to contact with these colder rocks, gaseous hydrocarbons pass into a different phase state and (depending on the composition and environmental conditions) form deposits of liquid and solid minerals - oil, brown and coal, anthracite, graphite and even diamonds.
5. In the process of the formation of solid deposits, in accordance with the laws of self-organization of matter that are far from being studied, under appropriate conditions, the formation of ordered forms occurs, including those reminiscent of the forms of the living world.
And another very curious detail: before the "Carboniferous period" - at the end of Devon - the climate is rather cool and arid, and after - at the beginning of Perm - the climate is also cool and arid. Before the "Carboniferous period" we have a "red continent", and after we have the same "red continent" ...
The following logical question arises: was there a warm "Carboniferous period" at all ?!.
Not a million-year age of the Carboniferous and brown coal seams explains a number of strange artifacts found in coals:
Iron mug found in coal 300 million years old.
Toothed rack in hard coal
