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42-482: It serviced gas hydrate fields and exploration facilities at Mallik , Aput , and Langley , along with the ice-locked barges Wurmlinger and Arctic Star , which act as bases of operations for ice road crews and exploration personnel. In addition, the road was a key supply line for Tuktoyaktuk and the hamlet of Aklavik . A History channel blog announced that the second season of Ice Road Truckers would be based out of Inuvik. A CBC North story reported that

84-403: A fully atomic description of the solid lattice to estimate the phase diagram of H 2 O at negative pressures and T ≤ 300 K , and obtain the differences in chemical potentials between ice Ih and the empty hydrates, central to the van der Waals−Platteeuw theory. Jacobson et al. performed simulations using a monoatomic (coarse-grained) model developed for H 2 O that is capable of capturing

126-585: A more potent greenhouse gas than CO 2 (see Atmospheric methane ). The fast decomposition of such deposits is considered a geohazard , due to its potential to trigger landslides , earthquakes and tsunamis . However, natural gas hydrates do not contain only methane but also other hydrocarbon gases, as well as H 2 S and CO 2 . Air hydrates are frequently observed in polar ice samples. Pingos are common structures in permafrost regions. Similar structures are found in deep water related to methane vents. Significantly, gas hydrates can even be formed in

168-446: A set of parameters where hydrates could be formed, there are still ways to avoid their formation. Altering the gas composition by adding chemicals can lower the hydrate formation temperature and/or delay their formation. Two options generally exist: The most common thermodynamic inhibitors are methanol , monoethylene glycol (MEG), and diethylene glycol (DEG), commonly referred to as glycol . All may be recovered and recirculated, but

210-423: A solid compound consisting of large amounts of methane suspended within a crystal water structure that forms in deep oceans under extremely high pressure. If removed from a high-pressure, low-temperature environment, one cubic metre of solid methane clathrate expands to 164 cubic metres of gaseous methane. If such an expansion occurred, it may have weakened the integrity of the surrounding rock sufficiently to trigger

252-402: Is 85%. Clathrate hydrates are derived from organic hydrogen-bonded frameworks. These frameworks are prepared from molecules that "self-associate" by multiple hydrogen-bonding interactions. Small molecules or gases (i.e. methane , carbon dioxide , hydrogen ) can be encaged as a guest in hydrates. The ideal guest/host ratio for clathrate hydrates range from 0.8 to 0.9. The guest interaction with

294-476: Is a stub . You can help Misplaced Pages by expanding it . Gas hydrate Clathrate hydrates , or gas hydrates , clathrates , or hydrates , are crystalline water-based solids physically resembling ice , in which small non-polar molecules (typically gases ) or polar molecules with large hydrophobic moieties are trapped inside "cages" of hydrogen bonded , frozen water molecules . In other words, clathrate hydrates are clathrate compounds in which

336-432: Is a new and evolving technology. It requires extensive tests and optimisation to the actual system. While kinetic inhibitors work by slowing down the kinetics of the nucleation, anti-agglomerants do not stop the nucleation, but stop the agglomeration (sticking together) of gas hydrate crystals. These two kinds of inhibitors are also known as low dosage hydrate inhibitors , because they require much smaller concentrations than

378-857: Is derived from the Latin clathratus ( clatratus ), meaning 'with bars, latticed '. Gas hydrates usually form two crystallographic cubic structures: structure (Type) I (named sI ) and structure (Type) II (named sII ) of space groups P m 3 ¯ n {\displaystyle Pm{\overline {3}}n} and F d 3 ¯ m {\displaystyle Fd{\overline {3}}m} respectively. A third hexagonal structure of space group P 6 / m m m {\displaystyle P6/mmm} may also be observed (Type H). The unit cell of Type I consists of 46 water molecules, forming two types of cages – small and large. The unit cell contains two small cages and six large ones. The small cage has

420-424: Is greatly limited to very specific formation conditions; however, their mechanical stability renders theoretical and computer simulation methods the ideal choice to address their thermodynamic properties. Starting from very cold samples (110–145 K), Falenty et al. degassed Ne–sII clathrates for several hours using vacuum pumping to obtain a so-called ice XVI, while employing neutron diffraction to observe that (i)

462-765: Is termed as CO 2 hydrate. The term CO 2 hydrates are more commonly used these days with its relevance in anthropogenic CO 2 capture and sequestration. A nonstoichiometric compound, carbon dioxide hydrate, is composed of hydrogen-bonded water molecules arranged in ice-like frameworks that are occupied by molecules with appropriate sizes and regions. In structure I, the CO 2 hydrate crystallizes as one of two cubic hydrates composed of 46 H 2 O molecules (or D 2 O) and eight CO 2 molecules occupying both large cavities (tetrakaidecahedral) and small cavities (pentagonal dodecahedral). Researchers believed that oceans and permafrost have immense potential to capture anthropogenic CO 2 in

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504-644: The Mallik gas hydrate site in the Mackenzie Delta of northwestern Canadian Arctic . These natural gas hydrates are seen as a potentially vast energy resource and several countries have dedicated national programs to develop this energy resource. Clathrate hydrate has also been of great interest as technology enabler for many applications like seawater desalination, gas storage, carbon dioxide capture & storage, cooling medium for data centre and district cooling etc. Hydrocarbon clathrates cause problems for

546-510: The mass action law in solution or gas state. Clathrate hydrates were discovered to form blockages in gas pipelines in 1934 by Hammerschmidt that led to increase in research to avoid hydrate formation. In 1945, H. M. Powell analyzed the crystal structure of these compounds and named them clathrates . Gas production through methane hydrates has since been realized and has been tested for energy production in Japan and China. The word clathrate

588-476: The permafrost and oceanic sediments. Hydrates can also be synthesized through seed crystallization or using amorphous precursors for nucleation. Clathrates have been explored for many applications including: gas storage, gas production, gas separation, desalination , thermoelectrics , photovoltaics , and batteries. Naturally on Earth gas hydrates can be found on the seabed , in ocean sediments, in deep lake sediments (e.g. Lake Baikal ), as well as in

630-400: The permafrost regions. The amount of methane potentially trapped in natural methane hydrate deposits may be significant (10 to 10 cubic metres), which makes them of major interest as a potential energy resource. Catastrophic release of methane from the decomposition of such deposits may lead to a global climate change, referred to as the " clathrate gun hypothesis ", because CH 4 is

672-477: The Mesolithic population of Britain lost their lives. A 2021 study found that about 600 km (370 miles) of Scotland's northern and eastern coastline were affected, with water encroaching 29 km (18 miles) inland. With present-day populations and sea levels, a similar event today could devastate and destroy seafront and port areas of Arbroath, Stonehaven, Aberdeen, Inverness, Wick, and Montrose. While

714-660: The Norwegian Sea, 100 km (62 mi) north-west of the Møre coast. In around 6200 BCE, structural failures of the shelf caused three underwater landslides , which triggered very large tsunamis in the North Atlantic Ocean. The collapses involved an estimated 290 km (180 mi) length of coastal shelf, with a total volume of 3,500 km (840 cu mi) of debris. Based on carbon dating of plant material recovered from sediment deposited by

756-427: The absence of a liquid phase. Under that situation, water is dissolved in gas or in liquid hydrocarbon phase. In 2017, both Japan and China announced that attempts at large-scale resource extraction of methane hydrates from under the seafloor were successful. However, commercial-scale production remains years away. The 2020 Research Fronts report identified gas hydrate accumulation and mining technology as one of

798-573: The conventional thermodynamic inhibitors. Kinetic inhibitors, which do not require water and hydrocarbon mixture to be effective, are usually polymers or copolymers and anti-agglomerants (requires water and hydrocarbon mixture) are polymers or zwitterionic  – usually ammonium and COOH – surfactants being both attracted to hydrates and hydrocarbons. Empty clathrate hydrates are thermodynamically unstable (guest molecules are of paramount importance to stabilize these structures) with respect to ice, and as such their study using experimental techniques

840-524: The cooperation of two guest gases (large and small) to be stable. It is the large cavity that allows structure H hydrates to fit in large molecules (e.g. butane , hydrocarbons ), given the presence of other smaller help gases to fill and support the remaining cavities. Structure H hydrates were suggested to exist in the Gulf of Mexico. Thermogenically produced supplies of heavy hydrocarbons are common there. The molar fraction of water of most clathrate hydrates

882-477: The economics of methanol recovery is not favourable in most cases. MEG is preferred over DEG for applications where the temperature is expected to be −10 °C or lower due to high viscosity at low temperatures. Triethylene glycol (TEG) has too low vapour pressure to be suited as an inhibitor injected into a gas stream. More methanol is lost in the gas phase when compared to MEG or DEG. The use of kinetic inhibitors and anti-agglomerants in actual field operations

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924-541: The edge of Norway's continental shelf in the Norwegian Sea , approximately 6225–6170 BCE . The collapse involved an estimated 290 km (180 mi) length of coastal shelf, with a total volume of 3,500 km (840 cu mi) of debris, which caused a paleotsunami in the North Atlantic Ocean . Storegga ( Norwegian : Great Edge ) is located at the edge of Norway's continental shelf in

966-567: The empty sII hydrate structure decomposes at T ≥ 145 K and, furthermore, (ii) the empty hydrate shows a negative thermal expansion at T < 55 K , and it is mechanically more stable and has a larger lattice constant at low temperatures than the Ne-filled analogue. The existence of such a porous ice had been theoretically predicted before. From a theoretical perspective, empty hydrates can be probed using Molecular Dynamics or Monte Carlo techniques. Conde et al. used empty hydrates and

1008-413: The enclathrated guest molecules are never bonded to the lattice. The formation and decomposition of clathrate hydrates are first order phase transitions , not chemical reactions. Their detailed formation and decomposition mechanisms on a molecular level are still not well understood. Clathrate hydrates were first documented in 1810 by Sir Humphry Davy who found that water was a primary component of what

1050-811: The episodes of this season occur on the Tuktoyaktuk Winter Road. Four of the featured drivers from the first season took part: Alex Debogorski, Hugh Rowland, Drew Sherwood, and Rick Yemm. The road returned in 2012 for the sixth season of the show, with Debogorski the sole featured driver behind the wheel on this winter road. (The entirety of the Dempster Highway, as well as the Dalton Highway in Alaska , and Manitoba 's winter roads, were also featured.) This Northwest Territories road, road transport or highway-related article

1092-433: The form CO 2 hydrates. The utilization of additives to shift the CO 2 hydrate equilibrium curve in phase diagram towards higher temperature and lower pressures is still under scrutiny to make extensive large-scale storage of CO 2 viable in shallower subsea depths. Storegga Slide The three Storegga Slides ( Norwegian : Storeggaraset ) are amongst the largest known submarine landslides . They occurred at

1134-501: The host is limited to van der Waals forces. Certain exceptions exist in semiclathrates where guests incorporate into the host structure via hydrogen bonding with the host structure. Hydrates form often with partial guest filling and collapse in the absence of guests occupying the water cages. Like ice, clathrate hydrates are stable at low temperatures and high pressure and possess similar properties like electrical resistivity. Clathrate hydrates are naturally occurring and can be found in

1176-597: The host molecule is water and the guest molecule is typically a gas or liquid. Without the support of the trapped molecules, the lattice structure of hydrate clathrates would collapse into conventional ice crystal structure or liquid water. Most low molecular weight gases, including O 2 , H 2 , N 2 , CO 2 , CH 4 , H 2 S , Ar , Kr , Xe , and Cl 2 as well as some higher hydrocarbons and freons , will form hydrates at suitable temperatures and pressures. Clathrate hydrates are not officially chemical compounds, as

1218-651: The petroleum industry, because they can form inside gas pipelines , often resulting in obstructions. Deep sea deposition of carbon dioxide clathrate has been proposed as a method to remove this greenhouse gas from the atmosphere and control climate change . Clathrates are suspected to occur in large quantities on some outer planets , moons and trans-Neptunian objects , binding gas at fairly high temperatures. Clathrate hydrates were discovered in 1810 by Humphry Davy . Clathrates were studied by P. Pfeiffer in 1927 and in 1930, E. Hertel defined "molecular compounds" as substances decomposed into individual components following

1260-586: The pipe wall and thereby plug the pipeline. Once formed, they can be decomposed by increasing the temperature and/or decreasing the pressure. Even under these conditions, the clathrate dissociation is a slow process. Therefore, preventing hydrate formation appears to be the key to the problem. A hydrate prevention philosophy could typically be based on three levels of security, listed in order of priority: The actual philosophy would depend on operational circumstances such as pressure, temperature, type of flow (gas, liquid, presences of water etc.). When operating within

1302-609: The shape of a pentagonal dodecahedron (5 ) (which is not a regular dodecahedron) and the large one that of a tetradecahedron , specifically a hexagonal truncated trapezohedron (5 6 ). Together, they form a version of the Weaire–Phelan structure . Typical guests forming Type I hydrates are CO 2 in carbon dioxide clathrate and CH 4 in methane clathrate . The unit cell of Type II consists of 136 water molecules, again forming two types of cages – small and large. In this case there are sixteen small cages and eight large ones in

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1344-427: The slide. A second theory states that over time, streams from melting glaciers had carried trillions of tons of sediment to the edge of the continental shelf, where it accumulated in many layers. In this case, a trigger such as an earthquake could have caused a large area of seafloor to collapse into the deep Norwegian sea, thus carrying the enormous volume of accumulated sediment along with it. At, or shortly before,

1386-845: The tetrahedral symmetry of hydrates. Their calculations revealed that, under 1 atm pressure, sI and sII empty hydrates are metastable regarding the ice phases up to their melting temperatures, T = 245 ± 2 K and T = 252 ± 2 K , respectively. Matsui et al. employed molecular dynamics to perform a thorough and systematic study of several ice polymorphs, namely space fullerene ices, zeolitic ices, and aeroices, and interpreted their relative stability in terms of geometrical considerations. The thermodynamics of metastable empty sI clathrate hydrates have been probed over broad temperature and pressure ranges, 100 K ≤ T ≤ 220 K and 100 kPa ≤ p ≤ 500 MPa , by Cruz et al. using large-scale simulations and compared with experimental data at 100 kPa. The whole p – V – T surface obtained

1428-558: The time of the Second Storegga Slide, a land bridge known to archaeologists and geologists as Doggerland linked Britain , Denmark and the Netherlands across what is now the southern North Sea . This area is believed to have included a coastline of lagoons, marshes, mudflats and beaches, and to have been a rich hunting, fowling and fishing ground populated by Mesolithic human cultures. Although Doggerland

1470-435: The top 10 research fronts in the geosciences. Thermodynamic conditions favouring hydrate formation are often found in pipelines . This is highly undesirable, because the clathrate crystals might agglomerate and plug the line and cause flow assurance failure and damage valves and instrumentation. The results can range from flow reduction to equipment damage. Hydrates have a strong tendency to agglomerate and to adhere to

1512-466: The tsunami caused by the Second Storegga Slide would have been devastating for those within the run-in zone, ultimately the tsunami was neither universally catastrophic nor the reason behind the inundation of the last vestiges of Doggerland. Storegga has been thoroughly investigated as part of the preparation activities for the Ormen Lange gas field off the coast of Norway. The prevalent conclusion

1554-559: The tsunamis, the latest incident occurred around 6225–6170 BCE. In Scotland , traces of the subsequent tsunami have been recorded, with deposited sediment being discovered in Montrose Basin and the Firth of Forth up to 29 km (18 mi) inland and 4 m (13 ft) above current normal tide levels. The triggering mechanism is thought to have been an earthquake that induced a catastrophic expansion of methane clathrate ,

1596-494: The unit cell. The small cage again has the shape of a pentagonal dodecahedron (5 ), but the large one is a hexadecahedron (5 6 ). Type II hydrates are formed by gases like O 2 and N 2 . The unit cell of Type H consists of 34 water molecules, forming three types of cages – two small ones of different types, and one "huge". In this case, the unit cell consists of three small cages of type 5 , two small ones of type 4 5 6 and one huge of type 5 6 . The formation of Type H requires

1638-444: Was analyzed in terms of angle and distance descriptors of a classical tetrahedral structure and observed to occur essentially by means of angular alteration for ( p ,  T ) > (200 MPa, 200 K). The length of the hydrogen bonds responsible for framework integrity was insensitive to the thermodynamic conditions and its average value is r(̅O H) = 0.25 nm . Clathrate hydrate, which encaged CO 2 as guest molecule

1680-533: Was earlier thought to be solidified chlorine. Clathrates have been found to occur naturally in large quantities. Around 6.4 trillion ( 6.4 × 10 ) tonnes of methane is trapped in deposits of methane clathrate on the deep ocean floor . Such deposits can be found on the Norwegian continental shelf in the northern headwall flank of the Storegga Slide . Clathrates can also exist as permafrost , as at

1722-460: Was fitted by the universal form of the Parsafar and Mason equation of state with an accuracy of 99.7–99.9%. Framework deformation caused by applied temperature followed a parabolic law, and there is a critical temperature above which the isobaric thermal expansion becomes negative, ranging from 194.7 K at 100 kPa to 166.2 K at 500 MPa. Response to the applied ( p ,  T ) field

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1764-471: Was permanently submerged through a gradual rise in sea level, it has been hypothesized that coastal areas of both Britain and mainland Europe, extending over areas which are now submerged, would have been temporarily inundated by a tsunami triggered by the Storegga Slide. This event would have had a catastrophic impact on the Mesolithic population at the time. It is estimated that up to a quarter of

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