Misplaced Pages

#485514

54-562: The town is one of the centres of brown coal mining in Slovakia. The town is located in the upper Nitra River valley, between the Vtáčnik and Strážovské vrchy ranges, about 10 km (6.21 mi) from Prievidza . The first written record about Nováky was in 1113 as Nuovac . In 1942, during the reign of the Nazi puppet government of "Independent" Slovakia, nearby barracks were used for

108-409: 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 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

162-489: A car, such as hydrogen or battery, is strongly limited by the energy density of the alternative medium. The same mass of lithium-ion storage, for example, would result in a car with only 2% the range of its gasoline counterpart. If sacrificing the range is undesirable, much more storage volume is necessary. Alternative options are discussed for energy storage to increase energy density and decrease charging time, such as supercapacitors . No single energy storage method boasts

216-485: 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) 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

270-514: A corresponding enrichment and used for power generation– is equivalent to the energy content of nearly 10,000 kg of mineral oil or 14,000 kg of coal. Comparatively, coal , gas , and petroleum are the current primary energy sources in the U.S. but have a much lower energy density. The density of thermal energy contained in the core of a light-water reactor ( pressurized water reactor (PWR) or boiling water reactor (BWR)) of typically 1 GWe (1,000 MW electrical corresponding to ≈3,000 MW thermal)

324-560: 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

378-677: A given region of space and the volume of the system or region considered. Often only the useful or extractable energy is measured. It is sometimes confused with stored energy per unit mass , which is called specific energy or gravimetric energy density . There are different types of energy stored, corresponding to a particular type of reaction. In order of the typical magnitude of the energy stored, examples of reactions are: nuclear , chemical (including electrochemical ), electrical , pressure , material deformation or in electromagnetic fields . Nuclear reactions take place in stars and nuclear power plants, both of which derive energy from

432-473: A given volume. This (volumetric) energy density is given by where E is the electric field , B is the magnetic field , and ε and µ are the permittivity and permeability of the surroundings respectively. The solution will be (in SI units) in joules per cubic metre. In ideal (linear and nondispersive) substances, the energy density (in SI units) is where D is the electric displacement field and H

486-732: 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 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

540-399: A neutron star, does not have an equivalent anti-particle form, but would offer the same 100% conversion rate of mass to energy in the form of Hawking radiation . Even in the case of relatively small black holes (smaller than astronomical objects) the power output would be tremendous. Electric and magnetic fields can store energy and its density relates to the strength of the fields within

594-430: 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

SECTION 10

#1732797709486

648-413: 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

702-409: A source of heat or for use in a heat engine , the relevant quantity is the change in standard enthalpy or the heat of combustion . There are two kinds of heat of combustion: A convenient table of HHV and LHV of some fuels can be found in the references. For energy storage , the energy density relates the stored energy to the volume of the storage equipment, e.g. the fuel tank. The higher

756-410: Is a hardened, gem-like form of lignite used in various types of jewelry. Germany is the largest producer of lignite, followed by China , Russia , and United States . Lignite accounted for 8% of all U.S. coal production in 2019. – no data available Energy density In physics , energy density is the quotient between the amount of energy stored in a given system or contained in

810-563: 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

864-536: 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 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

918-433: Is in the range of 10 to 100 MW of thermal energy per cubic meter of cooling water depending on the location considered in the system (the core itself (≈30 m ), the reactor pressure vessel (≈50 m ), or the whole primary circuit (≈300 m )). This represents a considerable density of energy that requires a continuous water flow at high velocity at all times in order to remove heat from the core, even after an emergency shutdown of

972-734: 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 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

1026-426: Is liquid, it is generally less than the higher heat of combustion. But in the most relevant case of hydrogen, Δ G is 113 MJ/kg if water vapor is produced, and 118 MJ/kg if liquid water is produced, both being less than the lower heat of combustion (120 MJ/kg). See note above about use in fuel cells. High-pressure tanks weigh much more than the hydrogen they can hold. The hydrogen may be around 5.7% of

1080-565: Is matter itself, according to the mass-energy equivalence . This energy is described by E = mc , where c is the speed of light. In terms of density, m = ρV , where ρ is the mass per unit volume, V is the volume of the mass itself. This energy can be released by the processes of nuclear fission (~0.1%), nuclear fusion (~1%), or the annihilation of some or all of the matter in the volume V by matter- antimatter collisions (100%). The most effective ways of accessing this energy, aside from antimatter, are fusion and fission . Fusion

1134-492: 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

SECTION 20

#1732797709486

1188-449: Is the magnetizing field . In the case of absence of magnetic fields, by exploiting Fröhlich's relationships it is also possible to extend these equations to anisotropic and nonlinear dielectrics, as well as to calculate the correlated Helmholtz free energy and entropy densities. In the context of magnetohydrodynamics , the physics of conductive fluids, the magnetic energy density behaves like an additional pressure that adds to

1242-411: Is the process by which the sun produces energy which will be available for billions of years (in the form of sunlight and heat). However as of 2024, sustained fusion power production continues to be elusive. Power from fission in nuclear power plants (using uranium and thorium) will be available for at least many decades or even centuries because of the plentiful supply of the elements on earth, though

1296-489: The gas pressure of a plasma . When a pulsed laser impacts a surface, the radiant exposure , i.e. the energy deposited per unit of surface, may also be called energy density or fluence. The following unit conversions may be helpful when considering the data in the tables: 3.6  MJ = 1  kW⋅h ≈ 1.34  hp⋅h . Since 1 J = 10 MJ and 1 m = 10 L, divide joule / m by 10 to get MJ / L = GJ/m . Divide MJ/L by 3.6 to get kW⋅h /L. Unless otherwise stated,

1350-488: The potential to perform work on the surroundings by converting internal energy to work until equilibrium is reached. In cosmological and other contexts in general relativity , the energy densities considered relate to the elements of the stress-energy tensor and therefore do include the rest mass energy as well as energy densities associated with pressure . When discussing the chemical energy contained, there are different types which can be quantified depending on

1404-596: 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

1458-419: 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 the coal fly ash produced from its combustion, further increasing health risks. Lignite is brownish-black in color and has

1512-420: 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

1566-563: The assembly and detention of Slovak Jews from all over the country, pending their deportation to Nazi death camps in German-occupied Poland. The camp was guarded by the Slovak Hlinka Guard militia. Nováky has had town status since 1961. According to the 2001 census , the town had 4,402 inhabitants. 97.32% of inhabitants were Slovaks , 0.89% Czechs , 0.41 Roma and 0.25% Hungarians . The religious make-up

1620-436: The best in specific power , specific energy , and energy density. Peukert's law describes how the amount of useful energy that can be obtained (for a lead-acid cell) depends on how quickly it is pulled out. In general an engine will generate less kinetic energy due to inefficiencies and thermodynamic considerations—hence the specific fuel consumption of an engine will always be greater than its rate of production of

1674-666: The binding energy of nuclei. Chemical reactions are used by organisms to derive energy from food and by automobiles from the combustion of gasoline. Liquid hydrocarbons (fuels such as gasoline, diesel and kerosene) are today the densest way known to economically store and transport chemical energy at a large scale (1 kg of diesel fuel burns with the oxygen contained in ≈15 kg of air). Burning local biomass fuels supplies household energy needs ( cooking fires , oil lamps , etc.) worldwide. Electrochemical reactions are used by devices such as laptop computers and mobile phones to release energy from batteries. Energy per unit volume has

Nováky - Misplaced Pages Continue

1728-489: The energy density of the fuel, the more energy may be stored or transported for the same amount of volume. The energy of a fuel per unit mass is called its specific energy . The adjacent figure shows the gravimetric and volumetric energy density of some fuels and storage technologies (modified from the Gasoline article). Some values may not be precise because of isomers or other irregularities. The heating values of

1782-503: The fuel describe their specific energies more comprehensively. The density values for chemical fuels do not include the weight of the oxygen required for combustion. The atomic weights of carbon and oxygen are similar, while hydrogen is much lighter. Figures are presented in this way for those fuels where in practice air would only be drawn in locally to the burner. This explains the apparently lower energy density of materials that contain their own oxidizer (such as gunpowder and TNT), where

1836-528: The full potential of this source can only be realized through breeder reactors , which are, apart from the BN-600 reactor , not yet used commercially. Nuclear fuels typically have volumetric energy densities at least tens of thousands of times higher than chemical fuels. A 1 inch tall uranium fuel pellet is equivalent to about 1 ton of coal, 120 gallons of crude oil, or 17,000 cubic feet of natural gas. In light-water reactors , 1 kg of natural uranium – following

1890-931: 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

1944-413: The intended purpose. One is the theoretical total amount of thermodynamic work that can be derived from a system, at a given temperature and pressure imposed by the surroundings, called exergy . Another is the theoretical amount of electrical energy that can be derived from reactants that are at room temperature and atmospheric pressure. This is given by the change in standard Gibbs free energy . But as

1998-419: The kinetic energy of motion. Energy density differs from energy conversion efficiency (net output per input) or embodied energy (the energy output costs to provide, as harvesting , refining , distributing, and dealing with pollution all use energy). Large scale, intensive energy use impacts and is impacted by climate , waste storage , and environmental consequences . The greatest energy source by far

2052-881: 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

2106-473: The large redundancy required to permanently control the neutron reactivity and to remove the residual heat from the core of NPP's. Because antimatter-matter interactions result in complete conversion from the rest mass to radiant energy, the energy density of this reaction depends on the density of the matter and antimatter used. A neutron star would approximate the most dense system capable of matter-antimatter annihilation. A black hole , although denser than

2160-473: 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

2214-407: 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

Nováky - Misplaced Pages Continue

2268-408: The mass of the oxidizer in effect adds weight, and absorbs some of the energy of combustion to dissociate and liberate oxygen to continue the reaction. This also explains some apparent anomalies, such as the energy density of a sandwich appearing to be higher than that of a stick of dynamite. Given the high energy density of gasoline, the exploration of alternative media to store the energy of powering

2322-746: 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,

2376-540: The reactor. The incapacity to cool the cores of three BWRs at Fukushima after the 2011 tsunami and the resulting loss of external electrical power and cold source caused the meltdown of the three cores in only a few hours, even though the three reactors were correctly shut down just after the Tōhoku earthquake . This extremely high power density distinguishes nuclear power plants (NPP's) from any thermal power plants (burning coal, fuel or gas) or any chemical plants and explains

2430-414: The risk of spontaneous combustion to the same level as black coal, increase 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

2484-400: The same physical units as pressure, and in many situations is synonymous . For example, the energy density of a magnetic field may be expressed as and behaves like a physical pressure. The energy required to compress a gas to a certain volume may be determined by multiplying the difference between the gas pressure and the external pressure by the change in volume. A pressure gradient describes

2538-422: 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

2592-409: 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

2646-401: 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

2700-566: The total mass, giving just 6.8 MJ per kg total mass for the LHV. See note above about use in fuel cells. The mechanical energy storage capacity, or resilience , of a Hookean material when it is deformed to the point of failure can be computed by calculating tensile strength times the maximum elongation dividing by two. The maximum elongation of a Hookean material can be computed by dividing stiffness of that material by its ultimate tensile strength. The following table lists these values computed using

2754-467: The values in the following table are lower heating values for perfect combustion , not counting oxidizer mass or volume. When used to produce electricity in a fuel cell or to do work , it is the Gibbs free energy of reaction (Δ G ) that sets the theoretical upper limit. If the produced H 2 O is vapor, this is generally greater than the lower heat of combustion, whereas if the produced H 2 O

SECTION 50

#1732797709486

2808-501: 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

2862-418: Was 75.91% Roman Catholics , 18.06% people with no religious affiliation and 1.57% Lutherans . This Trenčín District location article is a stub . You can help Misplaced Pages by expanding it . 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

2916-496: 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

#485514