Fossil coal

At different times and in different places in the geological past of the Earth, dense forests existed in wetland lowlands. Due to natural processes, such as floods, these forests were buried underground. As the soil layer above them increased, pressure increased. The temperature also rose as it descended. Under such conditions, plant material was protected from biodegradation and oxidation . The carbon absorbed by plants in huge peat bogs was eventually covered and deeply buried by sediments. Under high pressure and high temperature, dead vegetation is gradually converted to coal. Since coal consists mainly of carbon, the conversion of dead vegetation to coal is called carbonization.

Coal is formed under conditions when rotting plant material accumulates faster than its bacterial decomposition. The ideal environment for this is created in swamps , where stagnant water, poor in oxygen , interferes with the vital functions of bacteria and thereby protects the plant mass from complete destruction. At a certain stage of the process, the released acids prevent the further activity of bacteria . So there is peat - the initial product for the formation of coal. If then it is buried under other sediments, then peat undergoes compression and, losing water and gases, is converted to coal.

Under the pressure of one kilometer sedimentation, a layer of brown coal 4 meters thick is obtained from a 20-meter peat layer. If the depth of the burial of plant material reaches three kilometers, then the same layer of peat will turn into a layer of coal 2 meters thick. At a greater depth, about six kilometers, and at a higher temperature, a 20-meter layer of peat becomes an anthracite layer 1.5 meters thick.

For the formation of coal, abundant accumulation of plant mass is necessary. In ancient peat bogs , starting from the Devonian period (about 400 million years ago), organic matter was accumulated, from which fossil coals were formed without oxygen. Most industrial deposits of fossil coal date from this period, although there are younger deposits. The age of the most ancient coals is estimated at about 300-400 million years ^[3] .

The formation of large volumes of coal most likely ceased after the appearance of mushrooms , since the white rot of mushrooms completely decomposes lignin ^[4] .

In the wide, shallow seas of the Carboniferous period, ideal conditions existed for the formation of coal, although coals from most geological periods are known. The exception is the coal gap during the Permian-Triassic extinction , where coal is a rarity. Coal found in Precambrian layers that precede land plants is thought to have originated from the remains of algae.

As a result of the movement of the earth's crust, the coal seams experienced uplift and folding. Over time, the raised parts were destroyed due to erosion or spontaneous combustion, and the lowered ones were stored in wide shallow basins, where coal is at least 900 meters from the earth's surface. The formation of the most powerful coal seams is associated with regions of the earth's surface, over the area of ​​which significant volumes of bitumen mass were poured, as, for example, in Hat Creek ( Canada ), the total thickness of the coal seam pack reaches 450 m ^[5] .

Coal, like oil and gas , is an organic substance that undergoes slow decomposition under the influence of biological and geological processes. The basis of coal formation is bitumen masses and to a lesser extent (non-industrial reserves) from organic residues of plant origin. Four types of coal are distinguished depending on the degree of conversion and the specific amount of carbon in coal: brown coals ( lignites ), hard coals , anthracites and graphites . In Western countries, a slightly different classification takes place - lignites, sub-bituminous coals, bituminous coals, anthracites and graphites, respectively.

By origin, coals are divided into humic (from the remains of higher plants : wood, leaves, stems, etc.) and sapropelite coals (from the remains of lower plants , mainly algae) ^[6] .

Anthracite

Anthracite is the most deeply heated during its occurrence from fossil fuels, coal of the highest degree of coalification, a transition form from coal to graphite . It is characterized by high density and brilliance. Contains 95% carbon. It is used as a solid high-calorie fuel (calorific value of 6800–8350 kcal / kg). It has the highest calorific value, but is poorly flammable. It is formed from coal with increasing pressure and temperature at depths of the order of 6 kilometers.

Coal

Coal is a rock, which is a product of a deep metamorphism of bitumen masses pouring onto the surface of the planet Earth due to global tectonic disasters in various geological epochs of the planet's development. The greatest metamorphism is observed near the formed mountain ranges, at a greater occurrence depth under the influence of high temperatures, pressure and lack of oxygen. 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, when burning coal forming ash . Fossil coals differ from each other in the ratio of their constituent components, which determines their calorific value. 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%. They contain up to 12% moisture (3-4% internal), therefore they have a higher calorific value than lignite. It contains up to 32% of volatile substances, due to which it is well combustible. It is formed from brown coal at depths of the order of three kilometers.

Brown coal

Lignite - hard fossil coal formed from peat , contains 65-70% of carbon , has a brown color, the youngest of fossil coals. It is used as local fuel, as well as chemical raw materials. It contains a lot of water (43%), and therefore has a low calorific value . In addition, it contains a large number of volatile substances (up to 50%). They are formed from dead organic residues under load pressure and under the influence of elevated temperature at depths of the order of one kilometer.

Others

The composition and origin distinguish other varieties of coal:

alginite , algogelite , algocollinite , attroseminite , boghead , vitren , vitrinite , jet , gelite , gelitite , gelitolite , humite , humolite , desmit , duren , dyurit , interinite , calginite , cardif , kasnyanit , caustobiolite , kenlinit , klenlina , cla colloalgolite , colloseminite , collofusinite , colm , xylene , xylitin , xyloattrit , xylitovitr , xylodesmite , kulm , kutinit , leuptinitis , lignite , lignitite , lipoid , lipoidolite , lipoidotite , liptobiolite , mycystum , parenchitis , hemianthracite , resilitin , saprohumolite , saprocollite , sapropelite , semianthracite , semivitrinite , semicollinite , seminitis , semitelinitis , semifusene , semifusinite , sclerotinitis , sporinitis , sporopolite , suberinite , telginitolithinositolite , telginitis , telatinitolite , telatinitin , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinite , telatinitolite , fellinite , fiteral , fusen , fusenite , fusenolite , fusinite , fusite , fusitite , chermichite , exinite , electric coal , umite and others.

Coal mining methods depend on its depth. Development is carried out by an open method in coal mines , if the depth of the coal seam does not exceed one hundred meters. There are also frequent cases when, with an ever deeper deepening of the coal mine, it is further advantageous to develop the coal deposit underground. Mines are used to extract coal from great depths. The deepest mines in the Russian Federation mine coal from a level of just over one thousand two hundred meters. In conventional mining, about 40% of the coal is not recovered. The use of new methods of mine mining - a long face - allows you to extract more coal. ^[7]

Coal deposits contain, along with coal, many types of geo-resources with consumer value. These include host rocks as raw materials for the construction industry, groundwater, coalbed methane , rare and scattered elements, including precious metals and their compounds. For example, some coals are enriched with germanium .

World production reached a maximum of 8,254.9 million tons in 2013.

Coal Mining History in Russia

Peter I met with coal in 1696 , returning from the first Azov campaign in the area of ​​the present city of Shakhty (before the revolution Aleksandrovsk-Grushevsk). While resting on the shore of Kalmius, the king was shown a piece of black, well-burning mineral. “This mineral, if not for us, then for our descendants, will be beneficial to our descendants,” said Peter I.

An ore miner from the family of the clerk of the orderly hut, Grigory Kapustin , discovered coal in 1721 near a tributary of the Seversky Donets River, the Kundryuchya River, and proved its suitability for use in blacksmithing and iron-making. In December 1722, Peter I sent Kapustin with a registered decree for coal samples, and then special expedition equipment was prescribed for the exploration of coal and ore .

In 1722, the Berg College invited V. I. Gennin , who was in charge of the Ural and Siberian factories, "to try to find coal in the same way as in other European countries so that these coals could be of help."

The group of S. Kostylev in 1720-1721 conducted a search for minerals in the northern foothills of Altai . In February 1722, M. Volkov made an application for the iron ore he found in Tomsk Uyezd, and the coal he discovered in the "burnt mountain" seven miles from Verkhotomsky prison in the territory of the modern city of Kemerovo .

The formation of the coal industry in Russia dates back to the first quarter of the 19th century, when the main coal basins were already open.

Coal Mining and Reserves in Russia

In Russia, 5.5% of the world's coal reserves are concentrated, 272.1 billion tons of total reserves, including 193 billion tons of explored ones. This difference with the percentage of proven coal reserves is due to the fact that most of them are not suitable for development, since they are in the permafrost region . 70% falls on brown coal reserves.

Coal mining in Russia (RSFSR) , million tons:

• 1990 - 395;
• 1995 - 263;
• 2000 - 258;
• 2004 - 282 (76.1 million tons were exported);
• 2005 - 299 (79.61 million tons were exported);
• 2006 - 310;
• 2009 - 301 ^[9] ;
• 2010 - 323;
• 2011 - 334;
• 2012 - 354;
• 2013 - 352;
• 2014 - 356 (exports amounted to 155.6 million tons, including 153.2 million tons of coal and 2.4 million tons of brown coal);
• 2015 - 372 (exports amounted to 156.0 million tons, including 152.7 million tons of coal and 3.4 million tons of brown coal);
• 2016 - 385 (exports amounted to 171.4 million tons, including 166.1 million tons of coal and 5.3 million tons of brown coal). ^[ten]

The largest promising deposits in Russia

Elginskoye field ( Republic of Sakha (Yakutia) ). Belongs to Mechel OAO. The most promising object for open cast mining is located in the south-east of the Republic of Sakha (Yakutia), 415 km east of the city of Neryungri. The area of ​​the deposit is 246 km². The field is a shallow brachisynclinal asymmetric fold. Угленосны отложения верхней юры и нижнего мела. Основные угольные пласты приурочены к отложениям нерюнгринской (6 пластов мощностью 0,7—17 м) и ундыктанской (18 пластов мощностью также 0,7—17 м) свит. Большая часть ресурсов угля сосредоточена в четырёх пластах y4, y5, н15, н16 обычно сложного строения. Угли в основном полублестящие линзовидно-полосчатые с очень высоким содержанием наиболее ценного компонента — витринита (78—98 %). По степени метаморфизма угли относятся к III (жирной) стадии. Марка угля Ж, группа 2Ж. Угли средне- и высокозольные (15—24 %), малосернистые (0,2 %), малофосфористые (0,01 %), хорошо спекающиеся (Y = 28—37 мм), с высокой теплотой сгорания (28 МДж/кг). Эльгинский уголь можно обогатить до высших мировых стандартов и получить экспортный коксующийся уголь высокого качества. Месторождение представлено мощными (до 17 метров) пологими пластами с перекрывающими отложениями небольшой мощности (коэффициент вскрыши — около 3 м³ на тонну рядового угля), что очень выгодно для организации добычи открытым способом.

Элегестское месторождение ( Тува ) обладает запасами около 1 млрд т коксующегося угля дефицитной марки «Ж» (общий объём запасов оценивается в 20 млрд т). 80 % запасов находится в одном пласте толщиной 6,4 м (лучшие шахты Кузбасса работают в пластах толщиной 8-16 м, в Воркуте уголь добывают из пластов тоньше 1 м). После выхода на проектную мощность к 2012 году на Элегесте ожидается добыча 12 млн т угля ежегодно. Лицензия на разработку элегестских углей принадлежит Енисейской промышленной компании, которая входит в структуру «Объединенной промышленной корпорации» ( ОПК ). Правительственная комиссия по инвестиционным проектам РФ 22 марта 2007 года одобрила реализацию проектов по строительству железнодорожной линии « Курагино — Кызыл » в увязке с освоением минерально-сырьевой базы Республики Тыва (Тува).

Крупнейшие российские производители угля

В 2004 году добыча составляла:

• СУЭК — 79,5 млн тонн.
• Кузбассразрезуголь — 39,3 млн тонн.
• Южкузбассуголь — 18,1 млн тонн.
• Южный Кузбасс — 15,6 млн тонн.
• Угольная компания "Заречная" — 9,9 млн тонн.
• Красноярсккрайуголь — 3,7 млн тонн.

Основные угольные компании России

• Severstal
• SUEK
• Kuzbassrazrezugol
• Raspadskaya
• Угольная компания «Заречная»
• Mechel
• Sybuglemet
• Евраз

По данным на 2017 год, уголь занимал 16 место ^[11] в мировой торговле, по объёму стоимости. Общий объём рынка оценен в 122 млрд долл. США

Крупнейшими экспортерами выступили:

• Австралия 39 % ($47 млрд долл. США)
• Индонезия 16 % ($18,9 млрд долл. США)
• Россия 13 % ($16,1 млрд долл. США)
• США 8,7 % ($10,6 млрд долл. США)
• Колумбия 6,3 % ($7,63 млрд долл. США)
• ЮАР 5,1 % ($6,23 млрд долл. США)

Крупнейшими импортерами выступили:

• Япония 16 % ($19,5 млрд долл. США)
• Индия 16 % ($19,4 млрд долл. США)
• Китай 15 % ($17,8 млрд долл. США)
• Южная Корея 11 % ($13,3 млрд долл. США)
• другие страны Азии ($5,68 млрд долл. США)

Крупнейшие производители угля (США):

В 2004 году добыча составляла:

• Peabody Energy — 198 млн тонн.
• Arch Coal — 123 млн тонн.
• Consol Energy — 228 млн тонн.
• Foundation — 61 млн тонн.
• Massey — 42 млн тонн.

Coal consumption in millions of tons.

In England in 1735, they learned how to smel cast iron on coke. The use of coal is diverse. It is used as domestic, energy fuel, raw materials for the metallurgical and chemical industries, as well as for the extraction of rare and trace elements from it. Very promising is the liquefaction (hydrogenation) of coal with the formation of liquid fuel. For the production of 1 ton of oil, 2-3 tons of coal is consumed; during the embargo, South Africa almost completely provided itself with fuel due to this technology. Artificial graphite is obtained from fossil fuels.

Coal Cost

The cost varies greatly, as the quality of coal and the cost of transportation have a strong influence. In Russia as a whole, prices range from 60-400 rubles per ton (2000) to 600-1,300 rubles per ton (2008) . In the world market, the price reached $ 300 per tonne (2008) , and then fell to 3,500-3650 rubles per tonne (2010).

Coal Gasification

This direction of coal utilization is associated with its so-called "non-energy" use. We are talking about the processing of coal into other types of fuel (for example, combustible gas, medium temperature coke, etc.), preceding or accompanying the receipt of thermal energy from it. For example, in Germany during the Second World War, coal gasification technologies were actively used for the production of motor fuel. In South Africa, the SASOL plant using pressure-assisted gasification technology, the first developments of which were also carried out in Germany in the 30s – 40s of the 20th century, currently produces more than 100 products from brown coal. This gasification process is also known as the “Lurgi method”.

In the USSR, coal gasification technologies, in particular, were actively developed at the Research and Design Institute for the Development of the Kansk-Achinsk Coal Basin (KATEKNIIugol) in order to increase the efficiency of use of Kansk-Achinsk brown coal. The Institute employees developed a number of unique technologies for processing low-ash brown and hard coal. These coals can be subjected to energy technological processing into valuable products such as medium temperature coke , which can serve as a substitute for classic coke in a number of metallurgical processes, combustible gas suitable, for example, for burning in gas boilers as a substitute for natural gas, and synthesis gas , which can be used in the production of synthetic hydrocarbon fuels. Combustion of fuels obtained as a result of energy-technological processing of coal gives a significant gain in terms of harmful emissions relative to the combustion of source coal.

After the collapse of the USSR, KATEKNII, coal was eliminated, and the institute's employees involved in the development of coal gasification technologies created their own enterprise. In 1996, a plant was built to process coal into sorbent and combustible gas in the city of Krasnoyarsk (Krasnoyarsk Territory, Russia). The plant was based on the patented technology of coal-bed coal gasification with reverse blast (or the reverse process of coal-bed gasification of coal). This factory is currently operating. Due to the extremely low (compared with traditional coal combustion technologies) indicators of harmful emissions, it is freely located near the city center. Later on, based on the same technology, a demonstration plant for the production of household briquettes in Mongolia was also built (2008).

It should be noted some characteristic differences in the technology of layered coal gasification with reverse blast from the direct gasification process, one of the varieties of which (gasification under pressure) is used at the SASOL plant in South Africa. The combustible gas produced in the inverse process, unlike the direct process, does not contain coal pyrolysis products, therefore, in the inverse process, complex and expensive gas cleaning systems are not required. In addition, in the reversed process it is possible to organize incomplete gasification (carbonization) of coal. In this case, two useful products are produced at once: medium-temperature coke (carbonizate) and combustible gas. The advantage of the direct gasification process, on the other hand, is its higher productivity. During the period of the most active development of coal gasification technologies (the first half of the 20th century), this led to an almost complete lack of interest in the inverted process of coal gasification. However, at present the market situation is such that the cost of medium-temperature coke alone, produced in the inverted process of coal gasification (during carbonization), makes it possible to compensate for all costs of its production. Associated product - flammable gas suitable for combustion in gas boilers to produce heat and / or electric energy - in this case has a conditionally zero cost. This circumstance provides high investment attractiveness of this technology.

Another well-known technology for the gasification of brown coal is the energy-technological processing of coal into medium-temperature coke and thermal energy in a fluidized-bed (fluidized) bed of fuel. An important advantage of this technology is the possibility of its implementation by reconstruction of typical coal-fired boilers. At the same time, the boiler’s thermal energy productivity is maintained at the same level. A similar reconstruction project for a typical boiler was implemented, for example, at the Beryozovsky open pit mine (Krasnoyarsk Territory, Russia). In comparison with the technology of layer-by-layer gasification of coal, the energy-technological processing of coal into medium-temperature coke in the fluidized bed is characterized by a significantly higher (15–20 times higher) productivity. ^[13]

• see. Car with gas generator
• see Water-coal fuel

Coal Liquefaction

• According to scientists ^{[ what? ]} , explored ^{[ when? ]} coal reserves will last for about 171 years.
• see Fischer-Tropsch Synthesis
• see the Bergius Process

Coal as a fuel

The role of coal in the energy balance

In Russia, in 2005, the share of coal in the country's energy balance was about 18 percent (an average of 39% worldwide), and a little more than 20 percent in electricity production. The share of coal in the fuel balance of RAO UES in 2005 was 26%, and gas - 71%. Due to high world gas prices, the Russian government intended to increase the share of coal in the fuel balance of RAO UES of Russia up to 34% by 2010 , however, these plans were not destined to come true due to the cessation of RAO UES in 2008 .

Difficulties in using coal as an energy fuel

Despite the ongoing economic changes, the cost of 1 ton of standard fuel ( here ) on coal in most cases is the lowest compared to fuel oil and gas. The main difficulty in using coal is the high level of emissions from burning coal - gaseous and solid ( ash ). In most developed countries, however, in Russia, there are stringent requirements for the level of emissions allowed when burning coal. In EU countries, severe penalties are applied to CHP plants that exceed the norm (up to 50 euros for each generated MWh of electricity). The way out of the situation is to use various filters (for example, electrostatic precipitators) in the gas ducts of boilers, or to burn coal in the form of coal-water suspensions ( coal-water fuel ) ^[14] . In the latter case, due to the lower combustion temperature of coal, emissions of NO _x oxides (temperature NO _x ) are significantly (up to 70%) reduced. Ash obtained from the combustion of coal, in some cases can be used in the construction industry. Back in the USSR, GOSTs were developed, providing for the addition of ash to slag Portland cement. The difficulty of using ash is that ash is removed in most cases by ash removal, which complicates its loading for further transportation and use.

The specific heat of combustion of coal in comparison with other substances

Fossil coal contains harmful heavy metals such as mercury and cadmium (concentration from up to 0.0001 to 0.01% by weight) .

In underground coal mining, air dust content can exceed the MPC by hundreds of times ^{[15] [16]} . Under the working conditions that are available in mines, the continuous wearing of respirators is practically impossible (they require a quick change to clean new respirator masks for every severe pollution, do not allow communication, etc.), which does not allow using them as a means of reliable prevention of irreversible and incurable occupational diseases - silicosis , pneumoconiosis (and others). Therefore, in order to reliably protect the health of miners and coal workers in the United States, they use more effective means of collective defense ^{[17] [18]} .

• Vukolov S.P. , Mendeleev D.I. Stone coal // Encyclopedic Dictionary of Brockhaus and Efron : in 86 volumes (82 volumes and 4 additional). - SPb. , 1890-1907.
• Levinson-Lessing F.Yu. Coal // Brockhaus and Efron Encyclopedic Dictionary : in 86 volumes (82 volumes and 4 additional). - SPb. , 1890-1907.

• Virtual Museum of Coal - Kemerovo Scientific Center.