Coal is a readily combustible Combustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame. Fuels of interest often include organic compounds in the gas, liquid or black or brownish-black sedimentary rock Sedimentary rock is a type of rock that is formed by sedimentation of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle and accumulate or minerals to precipitate from a solution. Particles that form a sedimentary rock by accumulating normally occurring in rock strata In geology and related fields, a stratum is a layer of rock or soil with internally consistent characteristics that distinguishes it from contiguous layers. Each layer is generally one of a number of parallel layers that lie one upon another, laid down by natural forces. They may extend over hundreds of thousands of square kilometers of the Earth' in layers or veins called coal beds. The harder forms, such as anthracite coal Anthracite (Greek aνθρακίτης , "coal-like," from άνθραξ (ánthrax), coal) is a hard, compact variety of mineral coal that has a high luster. It has the highest carbon count and contains the fewest impurities of all coals, despite its lower calorific content, can be regarded as metamorphic rock Metamorphic rock is the result of the transformation of an existing rock type, the protolith, in a process called metamorphism, which means "change in form". The protolith is subjected to heat and pressure causing profound physical and/or chemical change. The protolith may be sedimentary rock, igneous rock or another older metamorphic because of later exposure to elevated temperature and pressure. Coal is composed primarily of carbon Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds. There are three naturally occurring isotopes, with 12C and 13C being stable, while 14C is radioactive, decaying with a half-life of along with variable quantities of other elements, chiefly sulfur Sulfur or sulphur is the chemical element that has the atomic number 16. It is denoted with the symbol S. It is an abundant, multivalent non-metal. Sulfur, in its native form, is a bright yellow crystalline solid. In nature, it can be found as the pure element and as sulfide and sulfate minerals. It is an essential element for life and is found in, hydrogen Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of 1.00794 u (1.007825 u for Hydrogen-1), hydrogen is the lightest and most abundant chemical element, constituting roughly 75 % of the Universe's elemental mass. Stars in the main sequence are mainly composed of hydrogen in its, oxygen Oxygen (pronounced /ˈɒksɨdʒɨn/, OK-si-jin, from the Greek roots ὀξύς (acid, literally "sharp", from the taste of acids) and -γενής (-genēs) (producer, literally begetter), is the element with atomic number 8 and represented by the symbol O. It is a member of the chalcogen group on the periodic table, and is a highly and nitrogen Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere[citation needed].
Coal begins as layers of plant matter accumulate at the bottom of a body of water. For the process to continue the plant matter must be protected from biodegradation Biodegradation is the chemical breakdown of materials by a physiological environment. The term is often used in relation to ecology, waste management and environmental remediation . Organic material can be degraded aerobically with oxygen, or anaerobically, without oxygen. A term related to biodegradation is biomineralisation, in which organic and oxidization, usually by mud or acidic water. The wide shallow seas of the Carboniferous The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Ma , to the beginning of the Permian Period, about 299.0 ± 0.8 Ma (ICS, 2004, period The geologic time scale provides a system of chronologic measurement relating stratigraphy to time that is used by geologists, paleontologists and other earth scientists to describe the timing and relationships between events that have occurred during the history of the Earth. The table of geologic time spans presented here agrees with the dates provided such conditions. This trapped atmospheric carbon in the ground in immense peat Peat, or turf, is an accumulation of partially decayed vegetation matter. Peat forms in wetland bogs, moors, muskegs, pocosins, mires, and peat swamp forests. Peat is harvested as an important source of fuel in certain parts of the world. By volume there are about 4 trillion m³ of peat in the world covering a total of around 2% of global land bogs A bog, quagmire or mire is a wetland type that accumulates acidic peat, a deposit of dead plant material—usually mosses, but also lichens in Arctic climates that eventually were covered over and deeply buried by sediments under which they metamorphosed Metamorphic rock is the result of the transformation of an existing rock type, the protolith, in a process called metamorphism, which means "change in form". The protolith is subjected to heat and pressure causing profound physical and/or chemical change. The protolith may be sedimentary rock, igneous rock or another older metamorphic into coal. Over time, the chemical and physical properties A physical property is any measurable property the value of which describes a physical system's state at any given moment in time. For that reason the changes in the physical properties of a system can be used to describe its transformations of the plant remains (believed to mainly have been fern A fern is any one of a group of about 12,000 species of plants. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants. Ferns do not have either seeds or flowers (they reproduce via spores)-like species antedating more modern plant and tree A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to 6 m; some authors set a minimum of 10 cm trunk diameter species) were changed by geological action to create a solid material.
Coal, a fossil fuel Fossil fuels are fuels formed by natural resources such as anaerobic decomposition of buried dead organisms. The age of the organisms and their resulting fossil fuels is typically millions of years, but exceeds 2 billion years. These fuels contain a high percentage of carbon and hydrocarbons, is the largest source of energy for the generation of electricity The fundamental principles of electricity generation were discovered during the 1820s and early 1830s by the British scientist Michael Faraday. His basic method is still used today: electricity is generated by the movement of a loop of wire, or disc of copper between the poles of a magnet worldwide, as well as one of the largest worldwide anthropogenic Anthropogenic effects, processes or materials are those that are derived from human activities, as opposed to those occurring in biophysical environments without human influence sources of carbon dioxide Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state. CO2 is a trace gas comprising 0.039% of the atmosphere emissions. Gross carbon dioxide emissions This is a list of sovereign states by carbon dioxide emissions due to human activity. The data presented below corresponds to emissions in 2006. The data itself were collected in 2007 by the CDIAC for United Nations. The data consider only carbon dioxide emissions from the burning of fossil fuels, but not emissions from deforestation, and fossil from coal usage are slightly more than those from petroleum Petroleum or crude oil is a naturally occurring, toxic, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights, and other organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling. It is refined and separated, most easily by and about double the amount from natural gas Natural gas is a gas consisting primarily of methane. It is found associated with other fossil fuels, in coal beds, as methane clathrates, and is created by methanogenic organisms in marshes, bogs, and landfills. It is an important fuel source, a major feedstock for fertilizers, and a potent greenhouse gas.[1] Coal is extracted from the ground by mining The goal of coal mining is to economically remove coal from the ground. Coal is valued for its energy content, and since the 1880s is widely used to generate electricity. Steel and cement industries use coal as a fuel for extraction of iron from iron ore and for cement production. In the United States, United Kingdom, and South Africa, a coal mine, either underground or in open pits Open-pit mining, also known as open-cast mining and open-cut mining, refers to a method of extracting rock or minerals from the earth by their removal from an open pit or borrow.
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Types
Believed approximate position of the proto-continents A continent is one of several large landmasses on Earth. They are generally identified by convention rather than any strict criteria, with seven regions commonly regarded as continents – they are : Asia, Africa, North America, South America, Antarctica, Europe, and Australia toward the end of the Carboniferous period The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Ma , to the beginning of the Permian Period, about 299.0 ± 0.8 Ma (ICS, 2004,; the light blue represents shallow seas where many of today's coal deposits are found, as opposed to deeper waters which gave rise to oil-bearing rocks derived from marine species. The ice caps were known to be very large, lowering sea levels extensively by locking up oceanic waters into solid ice, though how large the ice caps became is a matter of debate.As geological processes apply pressure Pressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure to dead biotic material Biotic material or biological derived material is any natural material that is originated from living organisms. Most such materials contain carbon and are capable of decay over time, under suitable conditions it is transformed successively into
- Peat Peat, or turf, is an accumulation of partially decayed vegetation matter. Peat forms in wetland bogs, moors, muskegs, pocosins, mires, and peat swamp forests. Peat is harvested as an important source of fuel in certain parts of the world. By volume there are about 4 trillion m³ of peat in the world covering a total of around 2% of global land, considered to be a precursor of coal, has industrial importance as a fuel in some regions, for example, Ireland and Finland. In its dehydrated form, peat is a highly effective absorbent for fuel and oil spills on land and water
- Lignite Lignite, often referred to as brown coal, or Rosebud coal by Northern Pacific Railroad, is a soft brown fuel with characteristics that put it somewhere between coal and peat. It is considered the lowest rank of coal; it is mined in Germany, Russia, the United States, Australia and many European countries, and it is used almost exclusively as a, also referred to as brown coal, is the lowest rank of coal and used almost exclusively as fuel for electric power generation. Jet Jet is a geological material and is considered to be a minor gemstone. Jet is not considered a true mineral, but rather a mineraloid as it has an organic origin, being derived from decaying wood under extreme pressure is a compact form of lignite that is sometimes polished and has been used as an ornamental stone since the Iron Age In archaeology, the Iron Age is the historical period in any area during which cutting tools and weapons were mainly made of iron or steel. The adoption of this material coincided with other changes in society, including differing agricultural practices, religious beliefs and artistic styles
- Sub-bituminous coal Sub-bituminous coal is a type of coal whose properties range from those of lignite to those of bituminous coal and are used primarily as fuel for steam-electric power generation, whose properties range from those of lignite to those of bituminous coal are used primarily as fuel for steam-electric power generation. Additionally, it is an important source of light aromatic hydrocarbons An aromatic hydrocarbon or arene (or sometimes aryl hydrocarbon) is a hydrocarbon with a conjugated cyclic molecular structure that is much more stable than the hypothetical localized structure. The term 'aromatic' was assigned before the physical mechanism determining aromaticity was discovered, and was derived from the fact that many of the for the chemical synthesis In chemistry, chemical synthesis is purposeful execution of chemical reactions to get a product, or several products. This happens by physical and chemical manipulations usually involving one or more reactions. In modern laboratory usage, this tends to imply that the process is reproducible, reliable, and established to work in multiple industry.
- Bituminous coal Bituminous coal or black coal is a relatively soft coal containing a tarlike substance called bitumen. It is of higher quality than lignite coal but of poorer quality than anthracite coal, dense mineral, black but sometimes dark brown, often with well-defined bands of bright and dull material, used primarily as fuel in steam-electric power generation, with substantial quantities also used for heat and power applications in manufacturing and to make coke Coke is the solid carbonaceous material derived from destructive distillation of low-ash, low-sulfur bituminous coal. Cokes from coal are grey, hard, and porous
- Steam coal is a grade between bituminous coal and anthracite, once widely used as a fuel for steam locomotives A steam locomotive is a locomotive powered by a steam engine. The term usually refers to its use on railways, but can also refer to a "road locomotive" such as a traction engine or steamroller. In this specialized use it is sometimes known as sea-coal in the U.S.[2] Small steam coal (dry small steam nuts or DSSN) was used as a fuel for domestic water heating Water heating is a thermodynamic process using an energy source to heat water above its initial temperature. Typical domestic uses of hot water are for cooking, cleaning, bathing, and space heating. In industry, both hot water and water heated to steam have many uses
- Anthracite Anthracite (Greek aνθρακίτης , "coal-like," from άνθραξ (ánthrax), coal) is a hard, compact variety of mineral coal that has a high luster. It has the highest carbon count and contains the fewest impurities of all coals, despite its lower calorific content, the highest rank; a harder, glossy, black coal used primarily for residential and commercial space heating A space heater is a self contained device for heating an enclosed area.. It is also known as a portable heater, a room heater or an auxiliary heater. Konosuke Matsushita is known for creating the first electric heater in 1929 known as Electric Kotatsu Heater, also known as the foot warmer. This heater had a double safety design with an efficient. It may be divided further into metamorphically altered bituminous coal and petrified oil, as from the deposits in Pennsylvania
- Graphite The mineral graphite is one of the allotropes of carbon. It was named by Abraham Gottlob Werner in 1789 from the Greek γράφειν : "to draw/write", for its use in pencils, where it is commonly called lead, as distinguished from the actual metallic element lead. Unlike diamond (another carbon allotrope), graphite is an electrical, technically the highest rank, but difficult to ignite and is not so commonly used as fuel: it is mostly used in pencils and, when powdered, as a lubricant.
The classification of coal is generally based on the content of volatiles. However, the exact classification varies between countries. According to the German classification, coal is classified as follows:[3]
| Name | Volatiles % | C Carbon % | H Hydrogen % | O Oxygen % | S Sulfur % | Heat content kJ/kg |
|---|---|---|---|---|---|---|
| Braunkohle (Lignite) | 45-65 | 60-75 | 6.0-5.8 | 34-17 | 0.5-3 | <28470 |
| Flammkohle (Flame coal) | 40-45 | 75-82 | 6.0-5.8 | >9.8 | ~1 | <32870 |
| Gasflammkohle (Gas flame coal) | 35-40 | 82-85 | 5.8-5.6 | 9.8-7.3 | ~1 | <33910 |
| Gaskohle (Gas coal) | 28-35 | 85-87.5 | 5.6-5.0 | 7.3-4.5 | ~1 | <34960 |
| Fettkohle (Fat coal) | 19-28 | 87.5-89.5 | 5.0-4.5 | 4.5-3.2 | ~1 | <35380 |
| Esskohle (Forge coal) | 14-19 | 89.5-90.5 | 4.5-4.0 | 3.2-2.8 | ~1 | <35380 |
| Magerkohle (Non baking coal) | 10-14 | 90.5-91.5 | 4.0-3.75 | 2.8-3.5 | ~1 | 35380 |
| Anthrazit (Anthracite) | 7-12 | >91.5 | <3.75 | <2.5 | ~1 | <35300 |
| Percent by weight | ||||||
The middle six grades in the table represent a progressive transition from the English-language sub-bituminous to bituminous coal, while the last class is an approximate equivalent to anthracite, but more inclusive (the U.S. anthracite has < 6% volatiles).
Cannel coal Cannel coal, also known as candle coal, is a type of coal, also classified as terrestrial type oil shale, with a large amount of hydrogen, which burns easily with a bright light and leaves little ash (sometimes called "candle coal"), is a variety of fine-grained, high-rank coal with significant hydrogen content. It consists primarily of "exinite Formerly, in coal geology, exinite was an umbrella term, used when referring to the finely-ground and macrerated remains, originally formed by spores, pollen, dinoflagellate cysts, leaf cuticles, plant resins and waxes, as found in coal deposits. Exinite is one of the four categories of kerogen. This term has been replaced by the term "" macerals, now termed "liptinite".
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Sun, 05 Sep 2010 19:06:32 GMT+00:00
-fired power plants The Hindu ... have signed a memorandum of understanding for the development of an advanced ultra super critical technology to be used for coal -fired power plants. ...
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age they were formed is called the Carboniferous Period It was part of the Paleozoic Era Carboniferous gets its name from carbon the basic element in coal and other fossil fuels The Carboniferous Period occurred from about 360 to 286 million years ago At the time the land was covered with swamps filled with huge trees ferns and other large leafy plants similar
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(May 7, 2008) Jennifer Wilcox, assistant professor of Energy Resources Engineering at Stanford University, discusses coal-based energy generation ... youtube.com.
