Misplaced Pages

#995004

104-510: Coal is a combustible black or brownish-black sedimentary rock , formed as rock strata called coal seams . Coal is mostly carbon with variable amounts of other elements , chiefly hydrogen , sulfur , oxygen , and nitrogen . Coal is a type of fossil fuel , formed when dead plant matter decays into peat which is converted into coal by the heat and pressure of deep burial over millions of years. Vast deposits of coal originate in former wetlands called coal forests that covered much of

208-510: A cyclothem . Cyclothems are thought to have their origin in glacial cycles that produced fluctuations in sea level , which alternately exposed and then flooded large areas of continental shelf. The woody tissue of plants is composed mainly of cellulose, hemicellulose, and lignin. Modern peat is mostly lignin, with a content of cellulose and hemicellulose ranging from 5% to 40%. Various other organic compounds, such as waxes and nitrogen- and sulfur-containing compounds, are also present. Lignin has

312-468: A blast wave. A piece of paper (made from wood ) catches on fire quite easily. A heavy oak desk is much harder to ignite, even though the wood fibre is the same in all three materials. Common sense (and indeed scientific consensus until the mid-1700s) would seem to suggest that material "disappears" when burned, as only the ash is left. Further scientific research has found that conservation of mass holds for chemical reactions. Antoine Lavoisier , one of

416-518: A building is subject to the local fire code, which is ordinarily enforced by the local fire prevention officer. For an Authority Having Jurisdiction , combustibility is defined by the local code. In the National Building Code of Canada , it is defined as follows: BS 476-4:1970 defines a test for combustibility in which a technician heats three specimens of a material in a furnace. Combustibile materials are those for which any of

520-553: A burning match, and spread flame rapidly. The technical definitions vary between countries so the United Nations created the Globally Harmonized System of Classification and Labeling of Chemicals , which defines the flash point temperature of flammable liquids as between 0 and 140 °F (60 °C) and combustible liquids between 140 °F (60 °C) and 200 °F (93 °C). Flammability

624-796: A comprehensive set of rules on combustible dust. When suspended in air (or any oxidizing environment), the fine particles of combustible dust present a potential for explosions. Accumulated dust , even when not suspended in air, remains a fire hazard. The National Fire Protection Association (U.S.) specifically addresses the prevention of fires and dust explosions in agricultural and food products facilities in NFPA Code section 61, and other industries in NFPA Code sections 651–664. Collectors designed to reduce airborne dust account for more than 40 percent of all dust explosions. Other important processes are grinding and pulverizing , transporting powders, filing silos and containers (which produces powder), and

728-466: A flash of fire when ignited by an external source. A lower flash point indicates higher flammability. Materials with flash points below 100  °F (38  °C ) are regulated in the United States by OSHA as potential workplace hazards . The flame point of a material is a temperature value at which sustained flame can be supported on the material once ignited by an external source. Once

832-560: A fuel for poor people compared to higher value hard coals. In Germany, briquettes are still readily available to end consumers in home improvement stores and supermarkets. An environmentally beneficial use of lignite is in agriculture. Lignite may have value as an environmentally benign soil amendment , improving cation exchange and phosphorus availability in soils while reducing availability of heavy metals, and may be superior to commercial K humates. Lignite fly ash produced by combustion of lignite in power plants may also be valuable as

936-488: A large market, manufacturers meet TB 117 in products that they distribute across the United States. The proliferation of flame retardants, and especially halogenated organic flame retardants, in furniture across the United States is strongly linked to TB 117. When it became apparent that the risk-benefit ratio of this approach was unfavorable and industry had used falsified documentation (i.e. see David Heimbach ) for

1040-445: A liquid, which varies with its temperature, is a measure of how much the vapor of the liquid tends to concentrate in the surrounding atmosphere as the liquid evaporates. Vapor pressure is a major determinant of the flash point and flame point, with higher vapor pressures leading to lower flash points and higher flammability ratings. The International Code Council (ICC) developed fire code requirements to provide adequate protection to

1144-416: A net wet basis. Lignite has a high content of volatile matter which makes it easier to convert into gas and liquid petroleum products than higher-ranking coals. Its high moisture content and susceptibility to spontaneous combustion can cause problems in transportation and storage. Processes which remove water from brown coal reduce the risk of spontaneous combustion to the same level as black coal, increase

SECTION 10

#1732772988996

1248-414: A process called carbonization . Carbonization proceeds primarily by dehydration , decarboxylation , and demethanation. Dehydration removes water molecules from the maturing coal via reactions such as Decarboxylation removes carbon dioxide from the maturing coal: while demethanation proceeds by reaction such as In these formulas, R represents the remainder of a cellulose or lignin molecule to which

1352-552: A range of concentrations. In addition to wood, combustible dusts include metals , especially magnesium, titanium and aluminum, as well as other carbon-based dusts . There are at least 140 known substances that produce combustible dust. While the particles in a combustible dusts may be of any size, normally they have a diameter of less than 420  μm . As of 2012 , the United States Occupational Safety and Health Administration has yet to adopt

1456-430: A result of increased temperatures and pressures underground. Lignite forms from peat that has not been subjected to deep burial and heating. It forms at temperatures below 100 °C (212 °F), primarily by biochemical degradation. This includes the process of humification, in which microorganisms extract hydrocarbons from peat and form humic acids, which decrease the rate of bacterial decay. In lignite, humification

1560-413: A soil amendment and fertilizer. However, rigorous studies of the long-term benefits of lignite products in agriculture are lacking. Lignite may also be used for the cultivation and distribution of biological control microbes that suppress plant pests. The carbon increases the organic matter in the soil while the biological control microbes provide an alternative to chemical pesticides. Leonardite

1664-536: A switch in fuels happened in London in the late sixteenth and early seventeenth centuries. Historian Ruth Goodman has traced the socioeconomic effects of that switch and its later spread throughout Britain and suggested that its importance in shaping the industrial adoption of coal has been previously underappreciated. The development of the Industrial Revolution led to the large-scale use of coal, as

1768-558: A tenth. Indonesia and Australia export the most, followed by Russia . The word originally took the form col in Old English , from reconstructed Proto-Germanic * kula ( n ), from Proto-Indo-European root * g ( e ) u-lo- "live coal". Germanic cognates include the Old Frisian kole , Middle Dutch cole , Dutch kool , Old High German chol , German Kohle and Old Norse kol . Irish gual

1872-713: A third of its electricity . Some iron and steel -making and other industrial processes burn coal. The extraction and burning of coal damages the environment , causing premature death and illness, and it is the largest anthropogenic source of carbon dioxide contributing to climate change . Fourteen billion tonnes of carbon dioxide were emitted by burning coal in 2020, which is 40% of total fossil fuel emissions and over 25% of total global greenhouse gas emissions . As part of worldwide energy transition , many countries have reduced or eliminated their use of coal power . The United Nations Secretary General asked governments to stop building new coal plants by 2020. Global coal use

1976-536: A very high amount of moisture , which partially explains its low carbon content. Lignite is mined all around the world and is used almost exclusively as a fuel for steam-electric power generation . Lignite combustion produces less heat for the amount of carbon dioxide and sulfur released than other ranks of coal. As a result, lignite is the most harmful coal to human health. Depending on the source, various toxic heavy metals , including naturally occurring radioactive materials , may be present in lignite and left over in

2080-402: A weight basis. This composition reflects partly the composition of the precursor plants. The second main fraction of coal is ash, an undesirable, noncombustable mixture of inorganic minerals. The composition of ash is often discussed in terms of oxides obtained after combustion in air: Of particular interest is the sulfur content of coal, which can vary from less than 1% to as much as 4%. Most of

2184-405: A weight composition of about 54% carbon, 6% hydrogen, and 30% oxygen, while cellulose has a weight composition of about 44% carbon, 6% hydrogen, and 49% oxygen. Bituminous coal has a composition of about 84.4% carbon, 5.4% hydrogen, 6.7% oxygen, 1.7% nitrogen, and 1.8% sulfur, on a weight basis. The low oxygen content of coal shows that coalification removed most of the oxygen and much of the hydrogen

SECTION 20

#1732772988996

2288-563: Is a soil conditioner rich in humic acids that is formed by natural oxidation when lignite comes in contact with air. The process can be replicated artificially on a large scale. The less matured xyloid (wood-shaped) lignite also contains high amounts of humic acid. Reaction with quaternary amine forms a product called amine-treated lignite (ATL), which is used in drilling mud to reduce fluid loss during drilling. Lignite may have potential uses as an industrial adsorbent . Experiments show that its adsorption of methylene blue falls within

2392-634: Is also a cognate via the Indo-European root. The conversion of dead vegetation into coal is called coalification . At various times in the geologic past, the Earth had dense forests in low-lying areas. In these wetlands, the process of coalification began when dead plant matter was protected from oxidation , usually by mud or acidic water, and was converted into peat . The resulting peat bogs , which trapped immense amounts of carbon, were eventually deeply buried by sediments. Then, over millions of years,

2496-481: Is also important in processes that produce combustible substances as a by-product . Special precautions are usually required for substances that are easily combustible. These measures may include installation of fire sprinklers or storage remote from possible sources of ignition. Substances with low combustibility may be selected for construction where the fire risk must be reduced, such as apartment buildings, houses, or offices. If combustible resources are used there

2600-428: Is burned in a turbine). Hot exhaust gases from the turbine are used to raise steam in a heat recovery steam generator which powers a supplemental steam turbine . The overall plant efficiency when used to provide combined heat and power can reach as much as 94%. IGCC power plants emit less local pollution than conventional pulverized coal-fueled plants. Other ways to use coal are as coal-water slurry fuel (CWS), which

2704-601: Is entirely vertical; however, metamorphism may cause lateral changes of rank, irrespective of depth. For example, some of the coal seams of the Madrid, New Mexico coal field were partially converted to anthracite by contact metamorphism from an igneous sill while the remainder of the seams remained as bituminous coal. The earliest recognized use is from the Shenyang area of China where by 4000 BC Neolithic inhabitants had begun carving ornaments from black lignite. Coal from

2808-515: Is greater chance of fire accidents and deaths. Fire resistant substances are preferred for building materials and furnishings. A non-combustible material is a substance that does not ignite, burn, support combustion, or release flammable vapors when subject to fire or heat, in the form in which it is used and under conditions anticipated. Any solid substance complying with either of two sets of passing criteria listed in Section 8 of ASTM E 136 when

2912-454: Is made when metallurgical coal (also known as coking coal ) is baked in an oven without oxygen at temperatures as high as 1,000 °C, driving off the volatile constituents and fusing together the fixed carbon and residual ash. Metallurgical coke is used as a fuel and as a reducing agent in smelting iron ore in a blast furnace . The carbon monoxide produced by its combustion reduces hematite (an iron oxide ) to iron. Pig iron , which

3016-409: Is more abundant, and anthracite. The % carbon in coal follows the order anthracite > bituminous > lignite > brown coal. The fuel value of coal varies in the same order. Some anthracite deposits contain pure carbon in the form of graphite . For bituminous coal, the elemental composition on a dry, ash-free basis of 84.4% carbon, 5.4% hydrogen, 6.7% oxygen, 1.7% nitrogen, and 1.8% sulfur, on

3120-431: Is now of lower importance than its use to generate electricity. Lignite is often found in thick beds located near the surface, making it inexpensive to mine. However, because of its low energy density , tendency to crumble, and typically high moisture content, brown coal is inefficient to transport and is not traded extensively on the world market compared with higher coal grades. It is often burned in power stations near

3224-507: Is now the accepted standard in American English and British English. Antonyms of "flammable" or "inflammable" include: non-flammable , non-inflammable , incombustible , non-combustible , not flammable , and fireproof . Flammable applies to combustible materials that ignite easily and thus are more dangerous and more highly regulated. Less easily ignited less-vigorously burning materials are combustible . For example, in

Coal - Misplaced Pages Continue

3328-520: Is of concern as cigarettes and candle accidents can trigger domestic fires. In 1975, California began implementing Technical Bulletin 117 (TB 117), which required that materials such as polyurethane foam used to fill furniture be able to withstand a small open flame, equivalent to a candle, for at least 12 seconds. In polyurethane foam, furniture manufacturers typically meet TB 117 with additive halogenated organic flame retardants . No other U.S. states had similar standards, but because California has such

3432-492: Is partial, coming to completion only when the coal reaches sub-bituminous rank. The most characteristic chemical change in the organic material during formation of lignite is the sharp reduction in the number of C=O and C-O-R functional groups. Lignite deposits are typically younger than higher-ranked coals, with the majority of them having formed during the Tertiary period. Lignite is often found in thick beds located near

3536-425: Is the ease with which a combustible substance can be ignited, causing fire or combustion or even an explosion. The degree of difficulty required to cause the combustion of a substance is quantified through fire testing . Internationally, a variety of test protocols exist to quantify flammability. The ratings achieved are used in building codes , insurance requirements, fire codes and other regulations governing

3640-418: Is the most flammable synthetic fiber. A fire test can be conducted to determine the degree of flammability. Test standards used to make this determination but are not limited to the following: Combustibility is a measure of how easily a substance bursts into flame, through fire or combustion . This is an important property to consider when a substance is used for construction or is being stored. It

3744-473: Is too rich in dissolved carbon, is also produced. Combustible The degree of flammability in air depends largely upon the volatility of the material - this is related to its composition-specific vapour pressure , which is temperature dependent. The quantity of vapour produced can be enhanced by increasing the surface area of the material forming a mist or dust. Take wood as an example. Finely divided wood dust can undergo explosive flames and produce

3848-462: Is typically just 25-35 percent. The energy content of lignite ranges from 10 to 20 MJ/kg (9–17 million BTU per short ton ) on a moist, mineral-matter-free basis. The energy content of lignite consumed in the United States averages 15 MJ/kg (13 million BTU/ton), on the as-received basis. The energy content of lignite consumed in Victoria, Australia, averages 8.6 MJ/kg (8.2 million BTU/ton) on

3952-449: Is used as fuel. 27.6% of world energy was supplied by coal in 2017 and Asia used almost three-quarters of it. Other large-scale applications also exist. The energy density of coal is roughly 24 megajoules per kilogram (approximately 6.7 kilowatt-hours per kg). For a coal power plant with a 40% efficiency, it takes an estimated 325 kg (717 lb) of coal to power a 100 W lightbulb for one year. In 2022, 68% of global coal use

4056-712: The Bronze Age (3000–2000 BC), where it formed part of funeral pyres . In Roman Britain , with the exception of two modern fields, "the Romans were exploiting coals in all the major coalfields in England and Wales by the end of the second century AD". Evidence of trade in coal, dated to about AD 200, has been found at the Roman settlement at Heronbridge , near Chester ; and in the Fenlands of East Anglia , where coal from

4160-519: The Fushun mine in northeastern China was used to smelt copper as early as 1000 BC. Marco Polo , the Italian who traveled to China in the 13th century, described coal as "black stones ... which burn like logs", and said coal was so plentiful, people could take three hot baths a week. In Europe, the earliest reference to the use of coal as fuel is from the geological treatise On Stones (Lap. 16) by

4264-473: The Imperial Sugar Company's plant at Port Wentworth, Georgia , resulting in thirteen deaths. A material's flash point is a metric of how easy it is to ignite the vapor of the material as it evaporates into the atmosphere . It is defined as the lowest material temperature required for fuel oils in the materials to begin to give off flammable vapors in the quantity high enough to support

Coal - Misplaced Pages Continue

4368-606: The Midlands was transported via the Car Dyke for use in drying grain. Coal cinders have been found in the hearths of villas and Roman forts , particularly in Northumberland , dated to around AD 400. In the west of England, contemporary writers described the wonder of a permanent brazier of coal on the altar of Minerva at Aquae Sulis (modern day Bath ), although in fact easily accessible surface coal from what became

4472-724: The Somerset coalfield was in common use in quite lowly dwellings locally. Evidence of coal's use for iron -working in the city during the Roman period has been found. In Eschweiler , Rhineland , deposits of bituminous coal were used by the Romans for the smelting of iron ore . No evidence exists of coal being of great importance in Britain before about AD 1000, the High Middle Ages . Coal came to be referred to as "seacoal" in

4576-598: The calorific value of brown coal to a black coal equivalent fuel, and significantly reduce the emissions profile of 'densified' brown coal to a level similar to or better than most black coals. However, removing the moisture increases the cost of the final lignite fuel. Lignite rapidly degrades when exposed to air. This process is called slacking or slackening . Most lignite is used to generate electricity. However, small amounts are used in agriculture , in industry , and even, as jet , in jewelry . Its historical use as fuel for home heating has continuously declined and

4680-480: The coal fly ash produced from its combustion, further increasing health risks. Lignite is brownish-black in color and has a carbon content of 60–70 percent on a dry ash-free basis. However, its inherent moisture content is sometimes as high as 75 percent and its ash content ranges from 6–19 percent, compared with 6–12 percent for bituminous coal . As a result, its carbon content on the as-received basis (i.e., containing both inherent moisture and mineral matter)

4784-489: The coal gap in the Permian–Triassic extinction event , where coal is rare. Favorable geography alone does not explain the extensive Carboniferous coal beds. Other factors contributing to rapid coal deposition were high oxygen levels, above 30%, that promoted intense wildfires and formation of charcoal that was all but indigestible by decomposing organisms; high carbon dioxide levels that promoted plant growth; and

4888-458: The occupancies as originally intended. In other words, if a portion of a building were designed as an apartment , one could not suddenly load it with flammable liquids and turn it into a gas storage facility, because the fire load and smoke development in that one apartment would be so immense as to overtax the active fire protection as well as the passive fire protection means for the building. The handling and use of flammable substances inside

4992-596: The railway network was dependent on lignite either through steam trains or electrified lines mostly fed with lignite derived power. As per the table below, East Germany was the largest producer of lignite for much of its existence as an independent state. In 2014, about 12 percent of Germany's energy and, specifically, 27 percent of Germany's electricity came from lignite power plants, while in 2014 in Greece , lignite provided about 50 percent of its power needs. Germany has announced plans to phase out lignite by 2038 at

5096-481: The steam engine took over from the water wheel . In 1700, five-sixths of the world's coal was mined in Britain. Britain would have run out of suitable sites for watermills by the 1830s if coal had not been available as a source of energy. In 1947 there were some 750,000 miners in Britain, but the last deep coal mine in the UK closed in 2015. A grade between bituminous coal and anthracite was once known as "steam coal" as it

5200-405: The 13th century; the wharf where the material arrived in London was known as Seacoal Lane, so identified in a charter of King Henry III granted in 1253. Initially, the name was given because much coal was found on the shore, having fallen from the exposed coal seams on cliffs above or washed out of underwater coal outcrops, but by the time of Henry VIII , it was understood to derive from the way it

5304-594: The Carboniferous, and suggested that climatic and tectonic factors were a more plausible explanation, reconstruction of ancestral enzymes by phylogenetic analysis corroborated a hypothesis that lignin degrading enzymes appeared in fungi approximately 200 MYa. One likely tectonic factor was the Central Pangean Mountains , an enormous range running along the equator that reached its greatest elevation near this time. Climate modeling suggests that

SECTION 50

#1732772988996

5408-595: The Central Pangean Mountains contributed to the deposition of vast quantities of coal in the late Carboniferous. The mountains created an area of year-round heavy precipitation, with no dry season typical of a monsoon climate. This is necessary for the preservation of peat in coal swamps. Coal is known from Precambrian strata, which predate land plants. This coal is presumed to have originated from residues of algae. Sometimes coal seams (also known as coal beds) are interbedded with other sediments in

5512-404: The Earth's tropical land areas during the late Carboniferous ( Pennsylvanian ) and Permian times. Coal is used primarily as a fuel. While coal has been known and used for thousands of years, its usage was limited until the Industrial Revolution . With the invention of the steam engine , coal consumption increased. In 2020, coal supplied about a quarter of the world's primary energy and over

5616-575: The Greek scientist Theophrastus (c. 371–287 BC): Among the materials that are dug because they are useful, those known as anthrakes [coals] are made of earth, and, once set on fire, they burn like charcoal [anthrakes]. They are found in Liguria ;... and in Elis as one approaches Olympia by the mountain road; and they are used by those who work in metals. Outcrop coal was used in Britain during

5720-509: The Latin inflammāre = "to set fire to", where the Latin preposition "in-" means "in" as in "indoctrinate", rather than "not" as in "invisible" and "ineligible". The word "inflammable" may be erroneously thought to mean "non-flammable". The erroneous usage of the word "inflammable" is a significant safety hazard . Therefore, since the 1950s, efforts to put forward the use of "flammable" in place of "inflammable" were accepted by linguists, and it

5824-437: The United States flammable liquids , by definition, have a flash point below 100 °F (38 °C)—where combustible liquids have a flash point above 100 °F (38 °C). Flammable solids are solids that are readily combustible, or may cause or contribute to fire through friction. Readily combustible solids are powdered , granular, or pasty substances that easily ignite by brief contact with an ignition source, such as

5928-420: The area remains saturated with water, which covers dead vegetation and protects it from atmospheric oxygen. Otherwise, peat swamps are found in a variety of climates and geographical settings. Anaerobic bacteria may contribute to the degradation of peat, but this process takes a long time, particularly in acidic water. Burial by other sediments further slows biological degradation, and subsequent transformations are

6032-500: The building and occupants. These codes specify the combustibility rating for materials, the entrance and exit requirements, as well as active fire protection requirements, along with numerous other things. In the U.S. other agencies have also developed building codes that specify combustibility ratings such as state and/or county governing bodies. Following the requirements of these fire codes are crucial for higher occupancy buildings. For existing buildings, fire codes focus on maintaining

6136-455: The change into account. Globally Harmonized System of Classification and Labelling of Chemicals uses a four category system to classify flammable liquids using flash point and boiling point temperature. This system is used internationally to evaluate and sort substances in industrial applications, workplaces and products distributed to consumers. Prior to 2012, OSHA's classification of flammable and combustible liquids in regulation 1910.106,

6240-810: The degree of flammability and combustibility in accordance with the German DIN 4102. DIN 4102, as well as its British cousin BS 476 include for testing of passive fire protection systems , as well as some of its constituent materials. The following are the categories in order of degree of combustibility and flammability: A more recent industrial standard is the European EN 13501-1 - Fire classification of construction products and building elements—which roughly replaces A2 with A2/B, B1 with C, B2 with D/E and B3 with F. B3 or F rated materials may not be used in building unless combined with another material that reduces

6344-427: The evolution of the first trees . But bacteria and fungi did not immediately evolve the ability to decompose lignin, so the wood did not fully decay but became buried under sediment, eventually turning into coal. About 300 million years ago, mushrooms and other fungi developed this ability, ending the main coal-formation period of earth's history. Although some authors pointed at some evidence of lignin degradation during

SECTION 60

#1732772988996

6448-516: The factors involved in coalification, temperature is much more important than either pressure or time of burial. Subbituminous coal can form at temperatures as low as 35 to 80 °C (95 to 176 °F) while anthracite requires a temperature of at least 180 to 245 °C (356 to 473 °F). Although coal is known from most geologic periods , 90% of all coal beds were deposited in the Carboniferous and Permian periods. Paradoxically, this

6552-507: The flame point of a material is reached, it produces enough fuel vapors or oils to support continuous burning. The lower flammability limit or lower explosive limit (LFL/LEL) represents the lowest air to fuel vapor concentration required for combustion to take place when ignited by an external source, for any particular chemical. Any concentration lower than this could not produce a flame or result in combustion. The upper flammability limit or upper explosive limit (UFL/UEL) represents

6656-412: The flame products (ash, water, carbon dioxide, and other gases). Lavoisier used the experimental fact that some metals gained mass when they burned to support his ideas (because those chemical reactions capture oxygen atoms into solid compounds rather than gaseous water). Historically, flammable , inflammable and combustible meant capable of burning . The word "inflammable" came through French from

6760-413: The flammability of those materials. Lignite Lignite (derived from Latin lignum meaning 'wood'), often referred to as brown coal , is a soft, brown, combustible sedimentary rock formed from naturally compressed peat . It has a carbon content around 25–35% and is considered the lowest rank of coal due to its relatively low heat content . When removed from the ground, it contains

6864-497: The form of iron pyrite (FeS 2 ). Being a dense mineral, it can be removed from coal by mechanical means, e.g. by froth flotation . Some sulfate occurs in coal, especially weathered samples. It is not volatilized and can be removed by washing. Minor components include: As minerals, Hg, As, and Se are not problematic to the environment, especially since they are only trace components. They become however mobile (volatile or water-soluble) when these minerals are combusted. Most coal

6968-931: The governments of Japan and Australia has begun extracting hydrogen from brown coal. The liquefied hydrogen will be shipped via the transporter Suiso Frontier to Japan. The largest lignite deposits in North America are the Gulf Coast lignites and the Fort Union lignite field. The Gulf Coast lignites are located in a band running from Texas to Alabama roughly parallel to the Gulf Coast. The Fort Union lignite field stretches from North Dakota to Saskatchewan . Both are important commercial sources of lignite. Lignite can be separated into two types: xyloid lignite or fossil wood , and compact lignite or perfect lignite. Although xyloid lignite may sometimes have

7072-475: The hazard posed by a substance during an emergency, such as a spill. In addition to GHS, flammability classifications are incorporated into various systems designed for communicating physical and health hazards in workplaces; such as American Coatings Association's Hazardous Materials Identification System (HMIS) and Lab Safety Supply's Hazardous Material Identification Guide (HMIG). Flammable substances include, but are not limited to: Flammability of furniture

7176-472: The heat and pressure of deep burial caused the loss of water, methane and carbon dioxide and increased the proportion of carbon. The grade of coal produced depended on the maximum pressure and temperature reached, with lignite (also called "brown coal") produced under relatively mild conditions, and sub-bituminous coal , bituminous coal , or anthracite coal (also called "hard coal" or "black coal") produced in turn with increasing temperature and pressure. Of

7280-431: The highest air to fuel vapor concentration at which combustion can take place when ignited by an external source. Any fuel-air mixture higher than this would be too concentrated to result in combustion. The values existing between these two limits represent the flammable or explosive range. Within this threshold, give an external ignition source, combustion of the particular fuel would likely happen. The vapor pressure of

7384-429: The increasing tendency of the anthracite to break with a conchoidal fracture , similar to the way thick glass breaks. As geological processes apply pressure to dead biotic material over time, under suitable conditions, its metamorphic grade or rank increases successively into: There are several international standards for coal. The classification of coal is generally based on the content of volatiles . However

7488-881: The land has been restored to full productivity. A bond (not necessary in this form) for mine reclamation is required in the US by the Surface Mining Control and Reclamation Act of 1977 . The Latrobe Valley in Victoria , Australia , contains estimated reserves of some 65 billion tonnes of brown coal. The deposit is equivalent to 25 percent of known world reserves. The coal seams are up to 98 m (322 ft) thick, with multiple coal seams often giving virtually continuous brown coal thickness of up to 230 m (755 ft). Seams are covered by very little overburden (10 to 20 m (33 to 66 ft)). A partnership led by Kawasaki Heavy Industries and backed by

7592-473: The latest. Greece has confirmed that the last coal plant will be shut in 2025 after receiving pressure from the European Union and plans to heavily invest in renewable energy . Lignite was and is used as a replacement for or in combination with firewood for home heating. It is usually pressed into briquettes for that use. Due to the smell it gives off when burned, lignite was often seen as

7696-407: The lignite is removed, restoration involves grading the mine spoil to as close an approximation as practical of the original ground surface (Approximate Original Contour or AOC). Subsoil and topsoil are restored and the land reseeded with various grasses. In North Dakota , a performance bond is held against the mining company for at least ten years after the end of mining operations to guarantee that

7800-578: The mines, such as in Poland's Bełchatów plant and Turów plant , Australia's Latrobe Valley and Luminant 's Monticello plant and Martin Lake plant in Texas. Primarily because of latent high moisture content and low energy density of brown coal, carbon dioxide emissions from traditional brown-coal-fired plants are generally much higher per megawatt-hour generated than for comparable black-coal plants, with

7904-556: The mixing and blending of powders. Investigation of 200 dust explosions and fires, between 1980 and 2005, indicated approximately 100 fatalities and 600 injuries. In January 2003, a polyethylene powder explosion and fire at the West Pharmaceutical Services plant in Kinston, North Carolina resulted in the deaths of six workers and injuries to 38 others. In February 2008 an explosion of sugar dust rocked

8008-450: The morphology and some properties of the original plant. In many coals, individual macerals can be identified visually. Some macerals include: In coalification huminite is replaced by vitreous (shiny) vitrinite . Maturation of bituminous coal is characterized by bitumenization , in which part of the coal is converted to bitumen , a hydrocarbon-rich gel. Maturation to anthracite is characterized by debitumenization (from demethanation) and

8112-405: The most important distinction is between thermal coal (also known as steam coal), which is burnt to generate electricity via steam; and metallurgical coal (also known as coking coal), which is burnt at high temperature to make steel . Hilt's law is a geological observation that (within a small area) the deeper the coal is found, the higher its rank (or grade). It applies if the thermal gradient

8216-406: The nature of Carboniferous forests, which included lycophyte trees whose determinate growth meant that carbon was not tied up in heartwood of living trees for long periods. One theory suggested that about 360 million years ago, some plants evolved the ability to produce lignin , a complex polymer that made their cellulose stems much harder and more woody. The ability to produce lignin led to

8320-453: The number of double bonds between carbon). As carbonization proceeds, aliphatic compounds convert to aromatic compounds . Similarly, aromatic rings fuse into polyaromatic compounds (linked rings of carbon atoms). The structure increasingly resembles graphene , the structural element of graphite. Chemical changes are accompanied by physical changes, such as decrease in average pore size. The macerals are coalified plant parts that retain

8424-406: The pioneers in these early insights, stated: "Nothing is lost, nothing is created, everything is transformed." The burning of a solid material may appear to lose weight if the mass of combustion gases (such as carbon dioxide and water vapor ) are not taken into account. The original mass of flammable material and the mass of the oxygen consumed (typically from the surrounding air) equals the mass of

8528-454: The pre-combustion treatment, turbine technology (e.g. supercritical steam generator ) and the age of the plant. A few integrated gasification combined cycle (IGCC) power plants have been built, which burn coal more efficiently. Instead of pulverizing the coal and burning it directly as fuel in the steam-generating boiler, the coal is gasified to create syngas , which is burned in a gas turbine to produce electricity (just like natural gas

8632-691: The range of activated carbons currently used by industry. Jet is a form of lignite that has been used as a gemstone. The earliest jet artifacts date to 10,000 BCE and jet was used extensively in necklaces and other ornamentation in Britain from the Neolithic until the end of Roman Britain . Jet experienced a brief revival in Victorian Britain . Lignite begins as partially decayed plant material, or peat. Peat tends to accumulate in areas with high moisture, slow land subsidence , and no disturbance by rivers or oceans – under these conditions,

8736-426: The reacting groups are attached. Dehydration and decarboxylation take place early in coalification, while demethanation begins only after the coal has already reached bituminous rank. The effect of decarboxylation is to reduce the percentage of oxygen, while demethanation reduces the percentage of hydrogen. Dehydration does both, and (together with demethanation) reduces the saturation of the carbon backbone (increasing

8840-540: The substance is tested in accordance with the procedure specified in ASTM E 136 is considered to be non-combustible. A number of industrial processes produce combustible dust as a by-product. The most common being wood dust . Combustible dust has been defined as: a solid material composed of distinct particles or pieces, regardless of size, shape, or chemical composition, which presents a fire or deflagration hazard when suspended in air or some other oxidizing medium over

8944-422: The subsurface beds. Topsoil and subsoil must be properly removed and either used to reclaim previously mined-out areas or stored for future reclamation. Excavator and truck overburden removal prepares the area for dragline overburden removal to expose the lignite beds. These are broken up using specially equipped tractors ( coal ripping ) and then loaded into bottom dump trucks using front loaders . Once

9048-399: The sulfur and most of the nitrogen is incorporated into the organic fraction in the form of organosulfur compounds and organonitrogen compounds . This sulfur and nitrogen are strongly bound within the hydrocarbon matrix. These elements are released as SO 2 and NO x upon combustion. They cannot be removed, economically at least, otherwise. Some coals contain inorganic sulfur, mainly in

9152-409: The surface. These are inexpensive to extract using various forms of surface mining , though this can result in serious environmental damage. Regulations in the United States and other countries require that land that is surface mined must be restored to its original productivity once mining is complete. Strip mining of lignite in the United States begins with drilling to establish the extent of

9256-401: The tenacity and the appearance of ordinary wood, it can be seen that the combustible woody tissue has experienced a great modification. It is reducible to a fine powder by trituration , and if submitted to the action of a weak solution of potash , it yields a considerable quantity of humic acid . Leonardite is an oxidized form of lignite, which also contains high levels of humic acid. Jet

9360-676: The three specimens either: Otherwise, the material is classified as non-combustible. Various countries have tests for determining non-combustibility of materials. Most involve the heating of a specified quantity of the test specimen for a set duration. Usually, the material must not support combustion and must not lose more than a certain amount of mass. As a general rule of thumb, concrete, steel, and ceramics - in other words inorganic substances - pass these tests, so building codes list them as suitable and sometimes even mandate their use in certain applications. In Canada , for instance, firewalls must be made of concrete . Materials can be tested for

9464-403: The use of building materials as well as the storage and handling of highly flammable substances inside and outside of structures and in surface and air transportation. For instance, changing an occupancy by altering the flammability of the contents requires the owner of a building to apply for a building permit to make sure that the overall fire protection design basis of the facility can take

9568-479: The use of flame retardants, California modified TB 117 to require that fabric covering upholstered furniture meet a smolder test replacing the open flame test . Gov. Jerry Brown signed the modified TB117-2013, which became effective in 2014. Lightweight textiles with porous surfaces are the most flammable fabrics. Wool is less flammable than cotton, linen, silk, or viscose ( rayon ). Polyester and nylon resist ignition, and melt rather than catch fire. Acrylic

9672-412: The world's coal-generated electricity. Efforts around the world to reduce the use of coal have led some regions to switch to natural gas and renewable energy . In 2018 coal-fired power station capacity factor averaged 51%, that is they operated for about half their available operating hours. Coke is a solid carbonaceous residue that is used in manufacturing steel and other iron-containing products. Coke

9776-501: The world's highest-emitting plant being Australia's Hazelwood Power Station until its closure in March 2017. The operation of traditional brown-coal plants, particularly in combination with strip mining , is politically contentious due to environmental concerns. The German Democratic Republic relied extensively on lignite to become energy self-sufficient , and eventually obtained 70% of its energy requirements from lignite. Lignite

9880-587: Was 8.3 billion tonnes in 2022, and is set to remain at record levels in 2023. To meet the Paris Agreement target of keeping global warming below 2 °C (3.6 °F) coal use needs to halve from 2020 to 2030, and "phasing down" coal was agreed upon in the Glasgow Climate Pact . The largest consumer and importer of coal in 2020 was China , which accounts for almost half the world's annual coal production, followed by India with about

9984-496: Was also an important chemical industry feedstock via Bergius process or Fischer-Tropsch synthesis in lieu of petroleum, which had to be imported for hard currency following a change in policy by the Soviet Union in the 1970s, which had previously delivered petroleum at below market rates. East German scientists even converted lignite into coke suitable for metallurgical uses ( high temperature lignite coke ) and much of

10088-572: Was based on the trading of this commodity. Coal continues to arrive on beaches around the world from both natural erosion of exposed coal seams and windswept spills from cargo ships. Many homes in such areas gather this coal as a significant, and sometimes primary, source of home heating fuel. Coal consists mainly of a black mixture of diverse organic compounds and polymers. Of course, several kinds of coals exist, with variable dark colors and variable compositions. Young coals (brown coal, lignite) are not black. The two main black coals are bituminous, which

10192-507: Was carried to London by sea. In 1257–1259, coal from Newcastle upon Tyne was shipped to London for the smiths and lime -burners building Westminster Abbey . Seacoal Lane and Newcastle Lane, where coal was unloaded at wharves along the River Fleet , still exist. These easily accessible sources had largely become exhausted (or could not meet the growing demand) by the 13th century, when underground extraction by shaft mining or adits

10296-549: Was developed in the Soviet Union , or in an MHD topping cycle . However these are not widely used due to lack of profit. In 2017 38% of the world's electricity came from coal, the same percentage as 30 years previously. In 2018 global installed capacity was 2 TW (of which 1TW is in China) which was 30% of total electricity generation capacity. The most dependent major country is South Africa, with over 80% of its electricity generated by coal; but China alone generates more than half of

10400-407: Was developed. The alternative name was "pitcoal", because it came from mines. Cooking and home heating with coal (in addition to firewood or instead of it) has been done in various times and places throughout human history, especially in times and places where ground-surface coal was available and firewood was scarce, but a widespread reliance on coal for home hearths probably never existed until such

10504-496: Was during the Late Paleozoic icehouse , a time of global glaciation . However, the drop in global sea level accompanying the glaciation exposed continental shelves that had previously been submerged, and to these were added wide river deltas produced by increased erosion due to the drop in base level . These widespread areas of wetlands provided ideal conditions for coal formation. The rapid formation of coal ended with

10608-550: Was nearly identical to the National Fire Protective Association (NFPA) Flammable and Combustible Liquids Code , NFPA 30. While no longer used for occupational regulations, NFPA 30's definitions are still commonly used in fire codes and NFPA codes and standards. Other systems for classifications of flammable liquids exist for more specialist applications, such as NFPA 704 , which uses five categories, intended for emergency workers to understand

10712-426: Was used for electricity generation. Coal burnt in coal power stations to generate electricity is called thermal coal . It is usually pulverized and then burned in a furnace with a boiler . The furnace heat converts boiler water to steam , which is then used to spin turbines which turn generators and create electricity. The thermodynamic efficiency of this process varies between about 25% and 50% depending on

10816-463: Was widely used as a fuel for steam locomotives . In this specialized use, it is sometimes known as "sea coal" in the United States. Small "steam coal", also called dry small steam nuts (DSSN), was used as a fuel for domestic water heating . Coal played an important role in industry in the 19th and 20th century. The predecessor of the European Union , the European Coal and Steel Community ,

#995004