Coal

Classification：Sedimentary Rock

A kind of flammable rock, a main fossil fuel. The carbon content is more than 50%. In most cases, coal is a kind of peat with rock.

Coal is a flammable black or brown black sedimentary rock. Such sedimentary rocks usually occur in lithostratigraphy or veins in Coal beds or Coal layers. Because later exposed to elevated temperature and pressure, a harder form of Coal can be considered as a metamorphic rock, such as smoke-free Coal. Coal is mainly composed of carbon, together with a number of other elements, mainly hydrogen, sulfur, oxygen and nitrogen.
Historically, Coal was used as a source of energy, mainly for the production of electricity and / or heat, and also for industrial use, such as refining metals, or producing chemical fertilizers and many chemical products. As a fossil fuel, the formation of Coal is that ancient plants were buried in the ground before the decay was decomposed, converted into peat, then converted to brown Coal, then Coal, then Coal, and finally smokeless Coal. The hydrocarbons produced by Coal are produced by the action of the pressure and temperature of the air of the crustal movement, which produce fossil carbonated minerals, that is, Coal carbon is a fossil plant. This involves a long period of biological and geological processes.

Components:
The main components of Coal are carbon, hydrogen, oxygen and a small amount of nitrogen, sulfur or other elements. Sulfur is one of the most important impurities in Coal. It usually occurs in the combustion products of Coal in the form of sulfide. In some countries, such as the United States has set up a standardized control of sulphide emissions, the government has rewarded the production of low sulfur Coal to reduce pollution because of the low cost of removing such harmful impurities.
Coal is considered to be the formation of ancient plant remains buried under the formation of peat, brown Coal, smoke Coal and smokeless Coal, and smokeless Coal can be further converted into graphite.

Classification:
According to the classification of its carbonization degree, it can be divided into peat, brown Coal (brown Coal, black HT Coal), tobacco Coal (Coal), smokeless Coal, and Coal (one kind of brown Coal, which is a specific classification of Japan). The degree of carbonization of smokeless Coal is the highest, and the degree of carbonization of peat is the lowest.
According to their classification of rock structure, they can be divided into candle Coal, silk carbon, dark Coal, bright Coal and mirror Coal. The mirror Coal contains more than 95% vitrinite, the surface of Coal is bright, the structure is solid, the vitrinite and the bright plastid are bright Coal, the coarse-grained Coal is dark, the filaments containing the filaments are silk, and the microsome formed by a lot of microspores is the candle Coal.
According to the number of volatile components contained in Coal, it can be classified into poor Coal (smokeless Coal, less than 12% volatile components), thin Coal (containing volatile 12-18%), coke Coal (containing volatile 18-26%), fertilizer Coal (containing volatile 26-35%), gas Coal (containing volatilization 35-44%), and long flame Coal (containing more than 42% volatile components. ). Among them, coke Coal and fertilizer Coal are most suitable for coking carbon, and the volatiles are too low and non cohesive, too high will not be used for coking, but the general coking should be combined with a variety of Coal.
In October 1989, People's Republic of China National Standard Bureau issued "China Coal carbon classification national standard" (GB5751-86), according to dry ash free volatile Vdaf, bond index G, glial layer maximum thickness Y, sub expansion B, Coal like transmittance P, Coal wet ash free base high calorific value Qgr, MAF and other 6 categories, The Coal is divided into 14 categories. That is, brown Coal, long flame Coal, non stick Coal, weak sticky Coal, Coal in 1/ 2, gas Coal, gas fertilizer Coal, 1/3 coke Coal, fertilizer Coal, coke Coal, lean lean, lean lean, lean and lean, and smoke-free.
According to the end use, the Coal charcoal produced in general can be divided into two types: coke Coal and electric Coal, all belong to the broad range of smoke Coal and sub tobacco Coal. Coke Coal and electric Coal market are relatively independent of each other.

Quality identification:
The quality identification of Coal should also be determined according to its calorific value, ash content (non burning part) and sulfur content. If the fuel is used, the high sulfur content will burn the sulfur dioxide to pollute the atmosphere. It is necessary to increase the cost of desulphurization and use as coking. The coefficient of expansion is also a major factor. [2]
The advantages and disadvantages of Coal carbon:
Advantages: Coal has abundant carbon resources, and because there are Coal carbon deposits all over the world, mining and supply are very stable, and the price is also cheaper than oil and natural gas.
Disadvantages: the calorific value of Coal carbon is smaller than that of oil or natural gas. When Coal carbon is burning, the amount of carbon dioxide emitted is higher than that of oil and natural gas. Production is limited, it is non renewable energy.

Use:
Coal is used as fuel
Coal is used for coking, which produces Coal tar and ammonia. Coke is an important raw material for ironmaking. Coal tar can extract many important industrial compounds. Many people think that Coal gas is made from Coal, but the fact is that Coal gas is extracted from crude oil and extracted from naphtha. Coal can also be directly vaporized to form a mixture of water Coal gas (carbon monoxide and hydrogen), which is directly used as clean fuel.
Coal, especially smoke Coal (any of the higher Coal of volatile matter) directly as fuel, will smoke black smoke, waste volatile components and cause air pollution. Britain is particularly sensitive to pollution due to the foggy climate. Early in the early twentieth Century, the law banned the original Coal as a direct fuel and only burnt coke or char.
Coke Coal and coke utilization
Coke, as an important raw material for iron making, plays a key role in the quality of pig iron. If sulfur and phosphorus are high, the quality of pig iron will be seriously reduced, and the high ash will reduce the calorific value. Therefore, Coal used for coking must be washed to reduce ash and sulfur content. A chain of coke must choose bulk solid, can not be crushed in the blast furnace, in order to ventilation. The selected char can only be used as fuel, and char as fuel has great calorific value and no smoke. It is a good fuel. [3]
Gasification of Coal
Coal gasification can be used to produce syngas, which is a mixture of carbon monoxide (CO) and hydrogen (H2) gas. Generally, synthetic gas is used to burn in a gas turbine to generate electricity, but, through the Fisher synthetic process, the versatility of synthetic gas is also allowed to be converted into fuel such as gasoline and diesel. Coal gasification combined Fischer Tropsch technology used Sasol chemical company of South Africa, from Coal and gas production of automotive fuel.
Liquefaction of Coal
Coal liquefaction is used to produce liquid synthetic fuels from Coal: methane and petrochemical products. Coal liquefaction can be divided into two types: direct liquefaction and indirect liquefaction. Direct liquefaction means carbonization and hydrogenation. Indirect liquefaction is to first vaporization of Coal, to generate water Coal gas, then to synthesize ethane, ethanol and other fuels, and to further synthesize fuel.
Production of chemical products
Coal carbon is an important raw material for producing many chemical fertilizers and other chemical products. The main production of these products
Jiao Tanlu of the smokeless fuel factory
Jiao Tanlu of the smokeless fuel factory
The way is Coal gasification to produce syngas. The production of primary chemical products directly from syngas, including methanol, hydrogen and carbon monoxide, is the basic component of chemical products. It can continue to produce the spectrum of chemical products of derivatives, including olefins, acetic acid, formaldehyde, ammonia, urea and so on. As a precursor of primary chemicals and high value derivatives, the versatility of syngas provides an option to use relatively cheap Coal carbon to produce a wide range of high value products.
Historically, Coal's chemical production has been used since 1950s, and the market has been established. According to the 2010 Global gasification database, in the current and planned gasifier investigations, the chemical production from 2004 to 2007 increased the share of the gasification of the products from 37% to 45%. From 2008 to 2010, 22% new gasifier is used for chemical production.

Mining methods:
Most of the smoke Coal and smoke-free Coal were obtained by deep mining Coal method, and modern technology has been used in open pit Coal method. The open pit Coal method needs to remove hundreds of tons of large excavators per hour and remove hundreds of feet of deep surface soil. Although the cost is low and the speed of expanding and digging is faster, it will destroy the environmental landscape. The depth of the general Coal method is from hundreds of feet to thousands of feet. A number of straight wells are usually required to be ventilated as tunnels, draining methane and reducing the heat and humidity inside the pit. About 90 of the Coal fields are used mechanically to pick up Coal and transport, so the transportation in the tunnel is mainly dependent on the conveyor belt, which conveyed the Coal to the straight well, and then sent out to the ground for cleaning, classification and other treatment.
The formation of the thinning degree of Coal ore:
The thickness of the Coal layer in a Coal mine is related to the decline speed of the crust and the accumulation of plant remains. The crustal decline is fast, the remains of the plant are stacked thick, the Coal layer of this Coal mine is thick, and conversely, the crustal decline is slow and the remains of the plant are thin, and the Coal layer of this Coal mine is thin.