Terpene

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Terpene

Many terpenes are derived commercially from conifer resins, such as those made by this pine.

Terpenes (/ˈtɜːrpiːn/) are a class of natural products consisting of compounds with the formula (C₅H₈)_n for n ≥ 2. Terpenes are major biosynthetic building blocks. Comprising more than 30,000 compounds, these unsaturated hydrocarbons are produced predominantly by plants, particularly conifers. In plants, terpenes and terpenoids are important mediators of ecological interactions, while some insects use some terpenes as a form of defense. Other functions of terpenoids include cell growth modulation and plant elongation, light harvesting and photoprotection, and membrane permeability and fluidity control.

Terpenes are classified by the number of carbons: monoterpenes (C₁₀), sesquiterpenes (C₁₅), diterpenes (C₂₀), as examples. The terpene alpha-pinene is a major component of the common solvent, turpentine.

The one terpene that has major applications is natural rubber (i.e., polyisoprene). The possibility that other terpenes could be used as precursors to produce synthetic polymers has been investigated. Many terpenes have been shown to have pharmacological effects. Terpenes are also components of some traditional medicines, such as aromatherapy, and as active ingredients of pesticides in agriculture. 

History and terminology

The term terpene was coined in 1866 by the German chemist August Kekulé to denote all hydrocarbons having the empirical formula C₁₀H₁₆, of which camphene was one. Previously, many hydrocarbons having the empirical formula C₁₀H₁₆ had been called "camphene", but many other hydrocarbons of the same composition had had different names. Kekulé coined the term "terpene" in order to reduce the confusion. The name "terpene" is a shortened form of "terpentine", an obsolete spelling of "turpentine".

Although sometimes used interchangeably with "terpenes", terpenoids (or isoprenoids) are modified terpenes that contain additional functional groups, usually oxygen-containing. The terms terpenes and terpenoids are often used interchangeably, however. Furthermore, terpenes are produced from terpenoids and many terpenoids are produced from terpenes. Both have strong and often pleasant odors, which may protect their hosts or attract pollinators. The number of terpenes and terpenoids is estimated at 55,000 chemical entities.

The 1939 Nobel Prize in Chemistry was awarded to Leopold Ružička "for his work on polymethylenes and higher terpenes", "including the first chemical synthesis of male sex hormones."

Biological function

Terpenes are major biosynthetic building blocks. Steroids, for example, are derivatives of the triterpene squalene. Terpenes and terpenoids are also the primary constituents of the essential oils of many types of plants and flowers. In plants, terpenes and terpenoids are important mediators of ecological interactions. For example, they play a role in plant defense against herbivory, disease resistance, attraction of mutualists such as pollinators, as well as potentially plant-plant communication appear to play roles as antifeedants. Other functions of terpenoids include cell growth modulation and plant elongation, light harvesting and photoprotection, and membrane permeability and fluidity control.

Higher amounts of terpenes are released by trees in warmer weather, where they may function as a natural mechanism of cloud seeding. The clouds reflect sunlight, allowing the forest temperature to regulate.

Some insects use some terpenes as a form of defense. For example, termites of the subfamily Nasutitermitinae ward off predatory insects through the use of a specialized mechanism called a fontanellar gun, which ejects a resinous mixture of terpenes.

Applications

Structure of natural rubber, exhibiting the characteristic methyl group on the alkene group

The one terpene that has major applications is natural rubber (i.e., polyisoprene). The possibility that other terpenes could be used as precursors to produce synthetic polymers has been investigated as an alternative to the use of petroleum-based feedstocks. However, few of these applications have been commercialized. Many other terpenes, however, have smaller scale commercial and industrial applications. For example, turpentine, a mixture of terpenes (e.g., pinene), obtained from the distillation of pine tree resin, is used as an organic solvent and as a chemical feedstock (mainly for the production of other terpenoids). Rosin, another by-product of conifer tree resin, is widely used as an ingredient in a variety of industrial products, such as inks, varnishes and adhesives. Rosin is also used by violinists (and players of similar bowed instruments) to increase friction on the bow hair. Terpenes are widely used as fragrances and flavors in consumer products such as perfumes, cosmetics and cleaning products, as well as food and drink products. For example, the aroma and flavor of hops comes, in part, from sesquiterpenes (mainly α-humulene and β-caryophyllene), which affect beer quality. Some form hydroperoxides that are valued as catalysts in the production of polymers.

Many terpenes have been shown to have pharmacological effects, although most studies are from laboratory research, and clinical research in humans is preliminary. Terpenes are also components of some traditional medicines, such as aromatherapy.

Reflecting their defensive role in plants, terpenes are used as active ingredients of pesticides in agriculture.

Tetrahydrocannabinol, a terpenoid, not a terpene, is the active ingredient in marijuana.

Physical and chemical properties

Terpenes are colorless, although impure samples are often yellow. Boiling points scale with molecular size: terpenes, sesquiterpenes, and diterpenes respectively at 110, 160, and 220 °C. Being highly non-polar, they are insoluble in water. Being hydrocarbons, they are highly flammable and have low specific gravity (float on water). They are tactilely light oils considerably less viscous than familiar vegetable oils like corn oil (28 cP), with viscosity ranging from 1 cP (à la water) to 6 cP. Terpenes are local irritants and can cause gastrointestinal disturbances if ingested.

Terpenoids (mono-, sesqui-, di-, etc.) have similar physical properties but tend to be more polar and hence slightly more soluble in water and somewhat less volatile than their terpene analogues. Highly polar derivatives of terpenoids are the glycosides, which are linked to sugars. These are water-soluble solids.

See also: Triterpene glycoside

Biosynthesis

Biosynthetic conversion of geranylpyrophosphate to the terpenes α-pinene and β-pinene and to the terpinoid α-terpineol.

Isoprene as the building block

Conceptually derived from isoprenes, the structures and formulas of terpenes follow the biogenetic isoprene rule or the C₅ rule, as described in 1953 by Leopold Ružička and colleagues. The C₅ isoprene units are provided in the form of dimethylallyl pyrophosphate (DMAPP) and isopentenyl pyrophosphate (IPP). DMAPP and IPP are structural isomers to each other. This pair of building blocks are produced by two distinct metabolic pathways: the mevalonate (MVA) pathway and the non-mevalonate (MEP) pathway. These two pathways are mutually exclusive in most organisms, except for some bacteria and land plants. In general, most archaea and eukaryotes use the MVA pathway, while bacteria mostly have the MEP pathway. IPP and DMAPP are final products of both MVA and MEP pathways and the relative abundance of these two isoprene units is enzymatically regulated in host organisms.

Organism	Pathways
Bacteria	MVA or MEP
Archaea	MVA
Green Algae	MEP
Plants	MVA and MEP
Animals	MVA
Fungi	MVA

Mevalonate pathway

Main article: Mevalonate pathway

This pathway conjugates three molecules of acetyl CoA.

The mevalonate (MVA) pathway is distributed in all three domains of life; archaea, bacteria and eukaryotes. The MVA pathway is universally distributed in archaea and non-photosynthetic eukaryotes, while the pathway is sparse in bacteria. In photosynthetic eukaryotes, some species possess the MVA pathway, while others have the MEP pathway or both MVA and MEP pathways. This is due to the acquisition of the MEP pathway by a common ancestor of Archaeplastida (algae + land plants) through the endosymbiosis of ancestral cyanobacteria that possessed the MEP pathway. The MVA and MEP pathways were selectively lost in individual photosynthetic lineages.

Also, the archaeal MVA pathway is not completely homologous to the eukaryotic MVA pathway. Instead, the eukaryotic MVA pathway is closer to the bacterial MVA pathway.

Non-mevalonate pathway

Main article: Non-mevalonate pathway

The non-mevalonate pathway or the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway starts with pyruvate and glyceraldehyde 3-phosphate (G3P) as the carbon source.

C₅ IPP and C₅ DMAPP are the end-products in either pathway and are the precursors of terpenoids with various carbon numbers (typically C₅ to C₄₀), side chains of (bacterio)chlorophylls, hemes and quinones. Synthesis of all higher terpenoids proceeds via formation of geranyl pyrophosphate (GPP), farnesyl pyrophosphate (FPP), and geranylgeranyl pyrophosphate (GGPP).

Geranyl pyrophosphate phase and beyond

Isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP) condense to produce geranyl pyrophosphate, precursor to all terpenes and terpenoids.

In both MVA and MEP pathways, IPP is isomerized to DMAPP by the enzyme isopentenyl pyrophosphate isomerase. IPP and DMAPP condense to give geranyl pyrophosphate, the precursor to monoterpenes and monoterpenoids.

Geranyl pyrophosphate is also converted to farnesyl pyrophosphate and geranylgeranyl pyrophosphate, respectively C₁₅ and C₂₀ precursors to sesquiterpenes and diterpenes (as well as sesequiterpenoids and diterpenoids). Biosynthesis is mediated by terpene synthase.

Terpenes to terpenoids

The genomes of many plant species contain genes that encode terpenoid synthase enzymes imparting terpenes with their basic structure, and cytochrome P450s that modify this basic structure.

Structure

Terpenes can be visualized as the result of linking isoprene (C₅H₈) units "head to tail" to form chains and rings. A few terpenes are linked “tail to tail”, and larger branched terpenes may be linked “tail to mid”.

Formula

Strictly speaking all monoterpenes have the same chemical formula C₁₀H₁₆. Similarly all sesquiterpenes and diterpenes have formulas of C₁₅H₂₄ and C₂₀H₃₂ respectively. The structural diversity of mono-, sesqui-, and diterpenes is a consequence of isomerism.

Chirality

Terpenes and terpenoids are usually chiral. Chiral compounds can exist as non-superposable mirror images, which exhibit distinct physical properties such as odor or toxicity.

Unsaturation

Most terpenes and terpenoids feature C=C groups, i.e. they exhibit unsaturation. Since they carry no functional groups aside from their unsaturation, terpenes are structurally distinctive. The unsaturation is associated with di- and trisubstituted alkenes. Di- and trisubstituted alkenes resist polymerization (low ceiling temperatures) but are susceptible to acid-induced carbocation formation.

Classification

• Selected terpenes
• 
  Limonene, a monoterpene.
• 
  
  Carvone is a monoterpenoid, a modified monoterpene.
• 
  Pinene, a monoterpene which exists as two isomers, is a major consistituent of turpentine.
• 
  Hinokitiol is a monoterpenoid, a tropolone derivative.
• 
  Humulene, a sesquiterpene.
• 
  Taxadiene, a diterpene, precursor to the diterpenoid taxol, an anticancer agent.
• 
  Squalene, a triterpene and universal precursor to natural steroids.
• 
  Geosmin is a sesquiterpenoid.

Terpenes may be classified by the number of isoprene units in the molecule; a prefix in the name indicates the number of isoprene pairs needed to assemble the molecule. Commonly, terpenes contain 2, 3, 4 or 6 isoprene units; the tetraterpenes (8 isoprene units) form a separate class of compounds called carotenoids; the others are rare.

• The basic unit isoprene itself is a hemiterpene. It may form oxygen-containing derivatives such as prenol and isovaleric acid analogous to terpenoids.
• Monoterpenes consist of two isoprene units and have the molecular formula C₁₀H₁₆. Examples of monoterpenes and monoterpenoids include geraniol, terpineol (present in lilacs), limonene (present in citrus fruits), myrcene (present in hops), linalool (present in lavender), hinokitiol (present in cypress trees) or pinene (present in pine trees). Iridoids derive from monoterpenes. Examples of iridoids include aucubin and catalpol.
• Sesquiterpenes consist of three isoprene units and have the molecular formula C₁₅H₂₄. Examples of sesquiterpenes and sesquiterpenoids include humulene, farnesenes, farnesol, geosmin. (The sesqui- prefix means one and a half.)
• Diterpenes are composed of four isoprene units and have the molecular formula C₂₀H₃₂. They derive from geranylgeranyl pyrophosphate. Examples of diterpenes and diterpenoids are cafestol, kahweol, cembrene and taxadiene (precursor of taxol). Diterpenes also form the basis for biologically important compounds such as retinol, retinal, and phytol.
• Sesterterpenes, terpenes having 25 carbons and five isoprene units, are rare relative to the other sizes. (The sester- prefix means two and a half.) An example of a sesterterpenoid is geranylfarnesol.
• Triterpenes consist of six isoprene units and have the molecular formula C₃₀H₄₈. The linear triterpene squalene, the major constituent of shark liver oil, is derived from the reductive coupling of two molecules of farnesyl pyrophosphate. Squalene is then processed biosynthetically to generate either lanosterol or cycloartenol, the structural precursors to all the steroids.
• Sesquarterpenes are composed of seven isoprene units and have the molecular formula C₃₅H₅₆. Sesquarterpenes are typically microbial in their origin. Examples of sesquarterpenoids are ferrugicadiol and tetraprenylcurcumene.
• Tetraterpenes contain eight isoprene units and have the molecular formula C₄₀H₆₄. Biologically important tetraterpenoids include the acyclic lycopene, the monocyclic gamma-carotene, and the bicyclic alpha- and beta-carotenes.
• Polyterpenes consist of long chains of many isoprene units. Natural rubber consists of polyisoprene in which the double bonds are cis. Some plants produce a polyisoprene with trans double bonds, known as gutta-percha.
• Norisoprenoids, characterized by the shortening of a chain or ring by the removal of a methylene group or substitution of one or more methyl side chains by hydrogen atoms. These include the C₁₃-norisoprenoid 3-oxo-α-ionol present in Muscat of Alexandria leaves and 7,8-dihydroionone derivatives, such as megastigmane-3,9-diol and 3-oxo-7,8-dihydro-α-ionol found in Shiraz leaves (both grapes in the species Vitis vinifera) or wine (responsible for some of the spice notes in Chardonnay), can be produced by fungal peroxidases or glycosidases.

Second- or third-instar caterpillars of Genus Papilio butterflies, like this Papilio glaucus, emit terpenes from their osmeterium.

Industrial syntheses

While terpenes and terpenoids occur widely, their extraction from natural sources is often problematic. Consequently, they are produced by chemical synthesis, usually from petrochemicals. In one route, acetone and acetylene are condensed to give 2-Methylbut-3-yn-2-ol, which is extended with acetoacetic ester to give geranyl alcohol. Others are prepared from those terpenes and terpenoids that are readily isolated in quantity, say from the paper and tall oil industries. For example, α-pinene, which is readily obtainable from natural sources, is converted to citronellal and camphor. Citronellal is also converted to rose oxide and menthol.

Summary of an industrial route to geranyl alcohol from simple reagents (wrong arrow. this is not a retrosynthesis)

Lignite

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Lignite

 

A lignite stockpile (above) and a lignite briquette

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 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.

The combustion for lignite 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 which are left over in the coal fly ash produced from its combustion, further increasing health risks.

Characteristics

Lignite mining, western North Dakota, US (c. 1945)

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) is typically just 25-35 percent.

Strip mining lignite at Tagebau Garzweiler in Germany

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 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. Unfortunately, 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 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.

Uses

Lignite mine in the background of Lützerath, Germany

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.

As fuel

Layer of lignite for mining in Lom ČSA, Czech Republic

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 the mines, such as in 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 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 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 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 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.

Home heating

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 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.

In agriculture

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 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 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.

In drilling mud

Reaction with quaternary amine forms a product called amine-treated lignite (ATL), which is used in drilling mud to reduce fluid loss during drilling.

As an industrial adsorbent

Lignite may have potential uses as an industrial adsorbent. Experiments show that its adsorption of methylene blue falls within the range of activated carbons currently used by industry.

In jewellery

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.

Geology

Okefenokee Swamp, a modern peat-forming swamp

Partial molecular structure of a lignin-derived organic molecule in lignite

Lignite begins as an accumulation of partially decayed plant material, or peat. Peat accumulates most readily in areas where there is ample moisture, slow subsidence of the land surface, and lack of disturbance by rivers or oceans. Peat swamps are otherwise found in a wide variety of climates and geographical settings. Under these conditions, the area remains saturated with water, which covers dead plant material and protects it from degradation by atmospheric oxygen. Anaerobic bacteria may continue to degrade the peat, but this process is slow, particularly in acid water. Once the peat is buried by other sediments, biological degradation essentially comes to a halt, and further changes are a result of increased temperature and pressure from burial.

Lignite forms from peat that has not experienced deep burial and heating. It forms at temperatures below 100 °C (212 °F), primarily by biochemical degradation. This includes humification, in which microorganisms extract hydrocarbons from the peat and humic acids are formed. The humic acids make the environment more acidic, which slows the rate of further bacterial decay. Humification is still incomplete in lignite, 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.

Extraction

Lignite is often found in thick beds located near 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 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 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 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.

Resources and reserves

List of countries by lignite reserves

Top Ten Countries by lignite reserves (2020)

Countries	Lignite reserves (billions of tons)
Russia	90.447
Australia	73.865
Germany	35.7
United States	29.91
Turkey	19.32
Pakistan	17.5
Indonesia	14.746
China	8.25
Republic of Kosovo	7.112
New Zealand	6.75
Poland	5.752

Australia

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 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.

North America

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.

Types

Lignite can be separated into two types. The first is xyloid lignite or fossil wood and the second form is the compact lignite or perfect lignite.

Although xyloid lignite may sometimes have 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 is a hardened, gem-like form of lignite used in various types of jewelry.

Production

This article needs to be updated. Please help update this article to reflect recent events or newly available information. (January 2023)

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.

Lignite mined in millions of tonnes

Country or territory	1970	1980	1990	2000	2010	2011	2012	2013	2014	2015
East Germany	261	258.1	280
Germany	108	129.9	107.6	167.7	169	176.5	185.4	183	178.2	178.1
China	–	24.3	45.5	47.7	125.3	136.3	145	147	145	140
Russia	145	141	137.3	87.8	76.1	76.4	77.9	73	70	73.2
Kazakhstan				2.6	7.3	8.4	5.5	6.5	6.6	–
Uzbekistan				2.5	3.4	3.8	3.8	–	–	–
United States	5	42.8	79.9	77.6	71.0	73.6	71.6	70.1	72.1	64.7
Poland	–	36.9	67.6	59.5	56.5	62.8	64.3	66	63.9	63.1
Turkey	–	14.5	44.4	60.9	70.0	72.5	68.1	57.5	62.6	50.4
Australia	–	32.9	46	67.3	68.8	66.7	69.1	59.9	58.0	63.0
Greece	–	23.2	51.9	63.9	56.5	58.7	61.8	54	48	46
India	–	5	14.1	24.2	37.7	42.3	43.5	45	47.2	43.9
Indonesia	–	–	–	–	40.0	51.3	60.0	65.0	60.0	60.0
Czechoslovakia	82	87	71
Czech Republic				50.1	43.8	46.6	43.5	40	38.3	38.3
Slovakia				3.7	2.4	2.4	2.3	–	–	–
Yugoslavia	–	33.7	64.1
Serbia				35.5	37.8	40.6	38	40.1	29.7	37.3
Kosovo					8.7	9	8.7	8.2	7.2	8.2
North Macedonia				7.5	6.7	8.2	7.5	–	–	–
Bosnia and Herzegovina				3.4	11	7.1	7	6.2	6.2	6.5
Slovenia				3.7	4	4.1	4	–	–	–
Montenegro					1.9	2	2	–	–	–
Romania	–	26.5	33.7	29	31.1	35.5	34.1	24.7	23.6	25.2
Bulgaria	–	30	31.5	26.3	29.4	37.1	32.5	26.5	31.3	35.9
Albania	–	1.4	2.1	30	14	9	20	–	–	–
Thailand	–	1.5	12.4	17.8	18.3	21.3	18.3	18.1	18	15.2
Mongolia	–	4.4	6.6	5.1	8.5	8.3	9.9	–	–	–
Canada	–	6	9.4	11.2	10.3	9.7	9.5	9.0	8.5	10.5
Hungary	–	22.6	17.3	14	9.1	9.6	9.3	9.6	9.6	9.3
North Korea	–	10	10.6	7.2	6.7	6.8	6.8	7	7	7

Light Water Reactor Sustainability Program

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Light_Water_Reactor_Sustainability_Program

The Light Water Reactor Sustainability Program is a U.S. government research and development program. It is directed by the United States Department of Energy and is aimed at performing research and compiling data necessary to qualify for licenses to extend the life of America's current 104 electricity generating nuclear power plants beyond 60 years of life. Practically all of the commercial electric-generating nuclear power plants currently in the United States are light water reactor (LWR) plants, meaning they use ordinary (light) water as a moderator and coolant simultaneously.

The basis for the project is founded on the facts that in the near future:

• demand for electricity is projected to increase significantly
• The U.S. has goals to significantly lower carbon dioxide emissions

Nuclear power was the largest contributor of non-greenhouse-gas-emitting electric power generation in the United States in 2009, comprising nearly three-quarters of the non-emitting sources. Energy efficiency, renewable energy, and carbon capture and storage technologies are expected to play increasing roles in providing clean and reliable energy.

During his presidential campaign, Barack Obama stated, "Nuclear power represents more than 70% of our noncarbon generated electricity. It is unlikely that we can meet our aggressive climate goals if we eliminate nuclear power as an option." The LWRS Program operates on the premise that electricity from nuclear generating stations, as a zero-carbon source, can and must play a critical role as part of an overall solution to both of these needs. The LWRS Program focuses on four main areas: Materials Aging and Degradation, Advanced Instrumentation, Information, and Control Systems Technologies, Advanced Light Water Reactor Nuclear Fuels, and finally, Risk-Informed Safety Margin Characterization.

Projected Increase in Demand

Domestic demand for electric energy is expected to grow by more than 30% from 2009 to 2035. At the same time, most of the currently operating nuclear power plants will begin reaching the end of their initial 20-year extension to their original 40-year operating license, for a total of 60 years of operation. According to one study, demand will increase by 30-40% by the year 2030. Other studies suggest an even higher increase in the world in general: above 80% by 2035.

Goals to lower carbon dioxide emissions

President Obama made clear the U.S.'s national stance on carbon dioxide emissions on the White House's website which stated, "We must take immediate action to reduce the carbon pollution that threatens our climate and sustains our dependence on fossil fuels."  The President has set a goal of reducing greenhouse gas emissions to 80% below 1990 levels by the year 2050.

Where it is happening

Idaho National Laboratory (INL) near Idaho Falls, Idaho and the Oak Ridge National Laboratory (ORNL) are the primary research facilities involved. Other labs and universities across the country are involved in specific parts of the research (see below).

Who is involved

Program Management

• Trevor Cook, LWRS Program Federal Project Director
• Bruce P. Hallbert, Director, LWRS Program Technical Integration Office
• Donald L. Williams, Jr., Deputy Director, LWRS Program Technical Integration Office
• Cathy J. Barnard, Operations Manager, LWRS Program Technical Integration Office
• Keith J. Leonard, Pathway Lead, Materials Aging and Degradation
• Bruce P. Hallbert, Pathway Lead, Advanced Instrumentation, Information, and Control Systems Technologies
• Curtis L. Smith, Risk-Informed Safety Margin Characterization
• Mitchell T. Farmer, Reactor Safety Technologies

Government

• U.S. Department of Energy Office of Nuclear Energy
• U.S. Nuclear Regulatory Commission

National Laboratories

• Idaho National Laboratory (INL)
• Oak Ridge National Laboratory (ORNL)
• Pacific Northwest National Laboratory (PNNL)
• Sandia National Laboratories (SNL)

Related Department of Energy Research and Development Programs

• Advanced Test Reactor (ATR) National Scientific User Facility
• Center for Advanced Energy Studies (CAES)
• Consortium for Advanced Simulation of LWRs (CASL)

Industry

• EPRI (Electric Power Research Institute)

Universities

• California State University, San Bernardino
• Colorado School of Mines
• Georgia Tech
• Mississippi State University
• Missouri State University
• Massachusetts Institute of Technology
• Ohio State University
• Oregon State University
• Texas A&M University
• University of California at Berkeley
• University of California Santa Barbara
• University of Michigan
• University of Wisconsin, Madison

International

• European Nuclear Plant Life Prediction
• Organisation for Economic Co-operation and Development (Halden Reactor Project)
• International Atomic Energy Agency Plant Life Management
• International Forum for Reactor Aging Management
• Materials Ageing Institute
• Nuclear Energy Agency Committee on the Safety of Nuclear Installation
• Organisation for Economic Co-operation and Development
• U.S.-Argentina Binational Energy Working Group

Primary Technical Areas of Research and Development

Materials Aging and Degradation

The Materials Aging and Degradation Pathway conducts research to develop the scientific basis for understanding and predicting long-term environmental degradation behavior of materials in nuclear power plants. Provide data and methods to assess performance of systems, structures, and components essential to safe and sustained nuclear power plant operation, providing key input to both regulators and industry.

Background

Nuclear reactors present a very challenging service environment. Components within the containment of an operating reactor must tolerate high-temperature water, stress, vibration, and an intense neutron field. Degradation of materials in this environment can lead to reduced performance and, in some cases, sudden failure.

Clearly, the demanding environments of an operating nuclear reactor may impact the ability of a broad range of materials to perform their intended function over extended service periods. Routine surveillance and repair/replacement activities can mitigate the impact of this degradation; however, failures still occur.

While all components potentially can be replaced, decisions to simply replace components may not be practical or the most economically favorable option. Therefore, understanding, controlling, and mitigating materials degradation processes and establishing a sound technical basis for long-range planning of necessary replacements are key priorities for extended nuclear power plants operations and power uprate considerations.

Purpose and Goals

The Materials Aging and Degradation Pathway provides research in many areas of materials science and technology, all supporting multiple Department of Energy missions and providing unique input to the evaluation of nuclear power plant life extension while complementing research and development efforts of the nuclear industry and regulators. The strategic goals of the pathway are to develop the scientific basis for understanding and predicting long-term environmental degradation behavior of materials in nuclear power plants and to provide data and methods to assess performance of systems, structures, and components essential to safe and sustained nuclear power plant operations.

The Department of Energy (through the Materials Aging and Degradation Pathway) is involved in this research and development activity to provide improved mechanistic understanding of key degradation modes and sufficient experimental data to provide and validate operational limits; provide new methods of monitoring degradation; and develop advanced mitigation techniques to provide improved performance, reliability, and economics.

Advanced Instrumentation, Information, and Control Systems Technologies

The Advanced Instrumentation, Information, and Control Systems Technologies Pathway conducts research to develop, demonstrate, and deploy new digital technologies for instrumentation and control architectures and provide monitoring capabilities to ensure the continued safe, reliable, and economic operation of the nation's operating nuclear power plants.

Background

Reliable instrumentation, information, and control systems technologies are essential to ensuring safe and efficient operation of the U.S. LWR fleet. These technologies affect every aspect of nuclear power plant and balance-of-plant operations. Current instrumentation and human-machine interfaces employ analog systems in the nuclear power sector. These systems, though generally considered by other industries to be obsolete, continue to function reliably, but do not enable utilities to take full advantage of digital technologies to achieve performance gains. Beyond control systems, new technologies are needed to monitor and characterize the effects of aging and degradation in critical areas of key systems, structures, and components. The objective of these efforts is to develop, demonstrate, and deploy new digital technologies for instrumentation information and control architectures and provide monitoring capabilities to ensure the continued safe, reliable, and economic operation of the nation's 104 nuclear power plants.

Purpose and Goals

The purpose of the Advanced Instrumentation, Information, and Control Systems Technologies Pathway is to enable the modernization of the legacy instrumentation information and control systems in a manner that creates a seamless digital environment encompassing all aspects of plant operations and support – building a three-dimensional information architecture that integrates plant systems, plant processes, and plant workers in an array of interconnected technologies.

Risk-Informed Safety Margin Characterization

The Risk-Informed Safety Margin Characterization Pathway conducts research to develop and deploy approaches to support the management of uncertainty in safety margins quantification to improve decision making for nuclear power plants. This pathway will (1) develop and demonstrate a risk-assessment method tied to safety margins quantification and (2) create advanced tools for safety assessment that enable more accurate representation of a nuclear power plant safety margin.

Background

Safety is central to the design, licensing, operation, and economics of nuclear power plants. As the current LWR nuclear power plants age beyond 60 years, there are possibilities for increased frequency of system, structures, and components failures that initiate safety-significant events, reduce existing accident mitigation capabilities, or create new failure modes. Plant designers commonly "over-design" portions of nuclear power plants and provide robustness in the form of redundant and diverse engineered safety features to ensure that, even in the case of well-beyond design basis scenarios, public health and safety will be protected with a very high degree of assurance.

The ability to better characterize and quantify safety margin holds the key to improved decision making about LWR design, operation, and plant life extension. A systematic approach to characterization of safety margins represents a vital input to the licensee and regulatory analysis and decision making that will be involved. In addition, as research and development in the LWRS Program and other collaborative efforts yield new data and improved scientific understanding of physical processes that govern the aging and degradation of plant systems, structures, and components (and concurrently support technological advances in nuclear reactor fuel and plant instrumentation, information, and control systems) needs and opportunities to better optimize plant safety and performance will become known.

Purpose

The purpose of the Risk-Informed Safety Margin Characterization Pathway is to develop and deploy approaches to support the management of uncertainty in safety margins quantification to improve decision making for nuclear power plants. Management of uncertainty implies the ability to (a) understand and (b) control risks related to safety. Consequently, the RISMC Pathway is dedicated to improving both aspects of safety management.

Advanced Light Water Reactor Nuclear Fuels

Conventional nuclear fuel pellet

The Advanced Nuclear Fuels Pathway conducts research to improve scientific knowledge basis for understanding and predicting fundamental nuclear fuel and cladding performance in nuclear power plants. Apply this information to development of high-performance, high burn-up fuels with improved safety, cladding integrity, and improved nuclear fuel cycle economics.

Background

Nuclear fuel performance is a significant driver of nuclear power plant operational performance, safety, operating economics, and waste disposal requirements (Over the past two decades, the nuclear power industry has improved plant capacity factors with incremental improvements achieved in fuel reliability and use or burnup). However, these upgrades are reaching their maximum achievable impact to achieve significant safety margin improvements while improving operating margins and economics, significant steps beyond incremental improvements in the current generation of nuclear fuel are required. Fundamental changes are required in the areas of nuclear fuel composition, cladding integrity, and the fuel/cladding interaction to reach the next levels of fuel performance. The technological improvements being developed in the Advanced LWR Nuclear Fuels Pathway center on development of revolutionary cladding materials supported by enhanced fuel mechanical designs and alternate fuel compositions. If realized, the changes would have substantial beneficial improvements in nuclear power plant economics, operation, and safety.

Purpose and Goals

The Advanced LWR Nuclear Fuels Pathway performs research on improving reactor safety, increasing fuel economics, producing advanced cladding designs, and developing enhanced computational models to predict fuel performance. Strategic research and development goals are directed at improving the scientific knowledge basis for understanding and predicting fundamental nuclear fuel and cladding performance in nuclear power plants, and applying the information to development of high-performance, high-burnup fuels with improved safety, cladding, integrity, and nuclear fuel cycle economics. This research is further designed to demonstrate each of the technology advancements while satisfying all safety and regulatory limits through rigorous testing and analysis.