Shale oil

Shale oil

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Shale oil, known also as kerogen oil or oil-shale oil, is an unconventional oil produced from oil shale
Oil shale
Oil shale, an organic-rich fine-grained sedimentary rock, contains significant amounts of kerogen from which liquid hydrocarbons called shale oil can be produced...

 by pyrolysis
Pyrolysis
Pyrolysis is a thermochemical decomposition of organic material at elevated temperatures without the participation of oxygen. It involves the simultaneous change of chemical composition and physical phase, and is irreversible...

, hydrogenation
Hydrogenation
Hydrogenation, to treat with hydrogen, also a form of chemical reduction, is a chemical reaction between molecular hydrogen and another compound or element, usually in the presence of a catalyst. The process is commonly employed to reduce or saturate organic compounds. Hydrogenation typically...

, or thermal dissolution
Thermal dissolution
Thermal dissolution is a hydrogen-donor solvent refining process. It may be used for the shale oil extraction and coal liquefaction‎. Other liquids extraction processes from solid fuels are pyrolysis and hydrogenation....

. These processes convert the organic matter within the rock (kerogen
Kerogen
Kerogen is a mixture of organic chemical compounds that make up a portion of the organic matter in sedimentary rocks. It is insoluble in normal organic solvents because of the huge molecular weight of its component compounds. The soluble portion is known as bitumen. When heated to the right...

) into synthetic oil and gas
Synthetic fuel
Synthetic fuel or synfuel is a liquid fuel obtained from coal, natural gas, oil shale, or biomass. It may also refer to fuels derived from other solids such as plastics or rubber waste. It may also refer to gaseous fuels produced in a similar way...

. The resulting oil can be used immediately as a fuel or upgraded
Upgrader
An upgrader is a facility that upgrades bitumen into synthetic crude oil. Upgrader plants are typically located close to oil sands production, for example, the Athabasca oil sands in Alberta, Canada or the Orinoco tar sands in Venezuela....

 to meet refinery
Oil refinery
An oil refinery or petroleum refinery is an industrial process plant where crude oil is processed and refined into more useful petroleum products, such as gasoline, diesel fuel, asphalt base, heating oil, kerosene, and liquefied petroleum gas...

 feedstock specifications by adding hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

 and removing impurities
Impurity
Impurities are substances inside a confined amount of liquid, gas, or solid, which differ from the chemical composition of the material or compound.Impurities are either naturally occurring or added during synthesis of a chemical or commercial product...

 such as sulfur
Sulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...

 and nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...

. The refined products can be used for the same purposes as those derived from crude oil.

History


Oil shale was one of the first sources of mineral oil
Mineral oil
A mineral oil is any of various colorless, odorless, light mixtures of alkanes in the C15 to C40 range from a non-vegetable source, particularly a distillate of petroleum....

 used by humans.
Its earliest recorded use was in Switzerland
Switzerland
Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....

 and Austria
Austria
Austria , officially the Republic of Austria , is a landlocked country of roughly 8.4 million people in Central Europe. It is bordered by the Czech Republic and Germany to the north, Slovakia and Hungary to the east, Slovenia and Italy to the south, and Switzerland and Liechtenstein to the...

 in the early 14th century. In 1596, the personal physician of Frederick I, Duke of Württemberg
Frederick I, Duke of Württemberg
Friedrich I of Württemberg was the son of Georg of Mömpelgard and his wife Barbara of Hesse, daughter of Philip I, Landgrave of Hesse....

 wrote of its healing properties. Shale oil was used to light the streets of Modena
Modena
Modena is a city and comune on the south side of the Po Valley, in the Province of Modena in the Emilia-Romagna region of Italy....

, Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...

 at the turn of the 17th century. The British Crown granted a patent in 1694 to three persons who had "found a way to extract and make great quantities of pitch, tarr, and oyle out of a sort of stone." Later sold as Betton's British Oil, the distilled product was said to have been "tried by divers persons in Aches and Pains with much benefit." Modern shale oil extraction industries were established in France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

 during the 1830s and in Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

 during the 1840s. The oil was used as fuel, as a lubricant, and as lamp oil; the Industrial Revolution
Industrial Revolution
The Industrial Revolution was a period from the 18th to the 19th century where major changes in agriculture, manufacturing, mining, transportation, and technology had a profound effect on the social, economic and cultural conditions of the times...

 had created additional demand for lighting. It served as a substitute for the increasingly scarce and expensive whale oil
Whale oil
Whale oil is the oil obtained from the blubber of various species of whales, particularly the three species of right whale and the bowhead whale prior to the modern era, as well as several other species of baleen whale...

.

During the late 19th century, shale oil extraction plants were built in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

, Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

 and the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. China (Manchuria
Manchuria
Manchuria is a historical name given to a large geographic region in northeast Asia. Depending on the definition of its extent, Manchuria usually falls entirely within the People's Republic of China, or is sometimes divided between China and Russia. The region is commonly referred to as Northeast...

), Estonia
Estonia
Estonia , officially the Republic of Estonia , is a state in the Baltic region of Northern Europe. It is bordered to the north by the Gulf of Finland, to the west by the Baltic Sea, to the south by Latvia , and to the east by Lake Peipsi and the Russian Federation . Across the Baltic Sea lies...

, New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

, South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

, Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...

, Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....

, and Switzerland
Switzerland
Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....

 produced shale oil in the early 20th century. The discovery of crude oil in the Middle East during mid-century brought most of these industries to a halt, although Estonia and Manchuria
Manchuria
Manchuria is a historical name given to a large geographic region in northeast Asia. Depending on the definition of its extent, Manchuria usually falls entirely within the People's Republic of China, or is sometimes divided between China and Russia. The region is commonly referred to as Northeast...

 maintained their extraction industries into the early 21st century. In response to rising petroleum costs at the turn of the 21st century, extraction operations have commenced, been explored, or been renewed in the United States, China, Australia, and Jordan
Jordan
Jordan , officially the Hashemite Kingdom of Jordan , Al-Mamlaka al-Urduniyya al-Hashemiyya) is a kingdom on the East Bank of the River Jordan. The country borders Saudi Arabia to the east and south-east, Iraq to the north-east, Syria to the north and the West Bank and Israel to the west, sharing...

.

Extraction process


Shale oil is extracted by pyrolysis, hydrogenation, or thermal dissolution of oil shale. The pyrolysis of the rock is performed in a retort
Retort
In a chemistry laboratory, a retort is a glassware device used for distillation or dry distillation of substances. It consists of a spherical vessel with a long downward-pointing neck. The liquid to be distilled is placed in the vessel and heated...

, situated either above ground or within the rock formation itself. As of 2008, most oil shale industries
Oil shale industry
Oil shale industry is an industry of mining and processing of oil shale—a fine-grained sedimentary rock, containing significant amounts of kerogen , from which liquid hydrocarbons can be manufactured. The industry has developed in Brazil, China, Estonia and to some extent in Germany, Israel and...

 perform the shale oil extraction process after the rock is mined, crushed, and transported to a retorting facility, although several experimental technologies perform the process in place (in-situ). The temperature at which the kerogen decomposes into usable hydrocarbons varies with the time-scale of the process; in the above-ground retorting process decomposition begins at 300 °C (572 °F), but proceeds more rapidly and completely at higher temperatures. Decomposition takes place most quickly at a temperature between 480 and 520 °C (896 and 968 °F).

Hydrogenation
Hydrogenation
Hydrogenation, to treat with hydrogen, also a form of chemical reduction, is a chemical reaction between molecular hydrogen and another compound or element, usually in the presence of a catalyst. The process is commonly employed to reduce or saturate organic compounds. Hydrogenation typically...

 and thermal dissolution
Thermal dissolution
Thermal dissolution is a hydrogen-donor solvent refining process. It may be used for the shale oil extraction and coal liquefaction‎. Other liquids extraction processes from solid fuels are pyrolysis and hydrogenation....

 (reactive fluid processes) extract the oil using hydrogen donors, solvent
Solvent
A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...

s, or a combination of these. Thermal dissolution involves the application of solvents at elevated temperatures and pressures, increasing oil output by cracking
Cracking (chemistry)
In petroleum geology and chemistry, cracking is the process whereby complex organic molecules such as kerogens or heavy hydrocarbons are broken down into simpler molecules such as light hydrocarbons, by the breaking of carbon-carbon bonds in the precursors. The rate of cracking and the end products...

 the dissolved organic matter. Different methods produce shale oil with different properties.

A critical measure of the viability of extraction of shale oil lies in the ratio of the energy produced by the oil shale to the energy used in its mining and processing, a ratio known as "Energy Returned on Energy Invested" (EROEI
EROEI
In physics, energy economics and ecological energetics, energy returned on energy invested ; or energy return on investment , is the ratio of the amount of usable energy acquired from a particular energy resource to the amount of energy expended to obtain that energy resource...

). A 1984 study estimated the EROEI of the various known oil-shale deposits as varying between 0.7–13.3. More recent studies estimates the EROEI of oil shales to be 1–2:1 or 2–16:1 – depending when self-energy is counted as a cost or internal energy is exclude and only purchased energy is counted as input. Royal Dutch Shell
Royal Dutch Shell
Royal Dutch Shell plc , commonly known as Shell, is a global oil and gas company headquartered in The Hague, Netherlands and with its registered office in London, United Kingdom. It is the fifth-largest company in the world according to a composite measure by Forbes magazine and one of the six...

 has reported an EROEI of three to four on its in situ development, Mahogany Research Project
Mahogany Research Project
The Shell's in situ conversion process is an in situ shale oil extraction technology to convert kerogen in oil shale to shale oil. It is developed by the Shell Oil Company.-History:...

.

The amount of oil that can be recovered during retorting varies with the oil shale and the technology used. About one sixth of the oil shales in the Green River Formation
Green River Formation
The Green River Formation is an Eocene geologic formation that records the sedimentation in a group of intermountain lakes. The sediments are deposited in very fine layers, a dark layer during the growing season and a light-hue inorganic layer in winter. Each pair of layers is called a varve and...

 have a relatively high yield of 25 to 100 US gal (94.6 to 378.5 ) of shale oil per ton of oil shale; about one third yield from 10 to 25 US gal (37.9 to 94.6 ) per ton. (Ten US gal/ton is approximately 3.4 tons of oil per 100 tons of shale.) About half of the oil shales in the Green River Formation yield less than 10 US gal/ton.

The major global shale oil producers have published their yields for their commercial operations. Fushun Mining Group
Fushun Mining Group
The Fushun Mining Group is a large state-owned coal and oil shale company located in Fushun, Liaoning Province, China. The corporation consists of 35 companies with more than 40,000 employees. The main business includes: coal mining, oil shale processing, machinery and others...

 reports producing 300,000 tons per year of shale oil from 6.6 million tons of shale, a yield of 4.5% by weight. VKG Oil claims to produce 250,000 tons of oil per year from 2 million tons of shale, a yield of 13%. Petrobras
Petrobras
Petróleo Brasileiro or Petrobras is a semi-public Brazilian multinational energy corporation headquartered in Rio de Janeiro, Brazil. It is the largest company in Latin America by market capitalization and revenue, and the largest company headquartered in the Southern Hemisphere by market...

 produces in their Petrosix
Petrosix
Petrosix is currently the world’s largest surface oil shale pyrolysis retort with an diameter vertical shaft kiln, operational since 1992. It is located in São Mateus do Sul, Brazil, and it is owned and operated by the Brazil energy company Petrobras. Petrosix means also the Petrosix process, an...

 plant 550 tons of oil per day from 6,200 tons of shale, a yield of 9%.

Properties


The properties of raw shale oil vary with the shale's composition and the extraction technology from aromatic to aliphatic. Typically it contains 0.5 to 1% oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

, 1.5 to 2% nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...

, and 0.15 to 1% sulfur
Sulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...

. Mineral particles are often present as well. The oil is less fluid than crude oil, becoming pourable
Pour point
The pour point of a liquid is the lowest temperature at which it will pour or flow under prescribed conditions. It is a rough indication of the lowest temperature at which oil is readily pumpable. In crude oil a high pour point is generally assosiated with a high paraffin content. And typically...

 at temperatures between 24 and 27 °C (75.2 and 80.6 °F), while conventional crude oil is pourable at temperatures between -60 °C; this property affects shale oil's ability to be transported in existing pipelines.

Upgrading


Although raw shale oil can be immediately burnt as a fuel oil, many of its applications require that it be upgraded. The differing properties of the raw oils call for correspondingly various pre-treatments before it can be sent to a conventional oil refinery
Oil refinery
An oil refinery or petroleum refinery is an industrial process plant where crude oil is processed and refined into more useful petroleum products, such as gasoline, diesel fuel, asphalt base, heating oil, kerosene, and liquefied petroleum gas...

.

Particulates in the raw oil clog downstream processes; sulfur
Sulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...

 and nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...

 create air pollution
Air pollution
Air pollution is the introduction of chemicals, particulate matter, or biological materials that cause harm or discomfort to humans or other living organisms, or cause damage to the natural environment or built environment, into the atmosphere....

. Sulfur and nitrogen, along with the arsenic
Arsenic
Arsenic is a chemical element with the symbol As, atomic number 33 and relative atomic mass 74.92. Arsenic occurs in many minerals, usually in conjunction with sulfur and metals, and also as a pure elemental crystal. It was first documented by Albertus Magnus in 1250.Arsenic is a metalloid...

 and iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

 that may be present, also destroy the catalysts used in refining. Olefins form insoluble sediments and cause instability. The oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

 within the oil, present at higher levels than in crude oil, lends itself to the formation of destructive free radicals. Hydrodesulfurization
Hydrodesulfurization
Hydrodesulfurization is a catalytic chemical process widely used to remove sulfur from natural gas and from refined petroleum products such as gasoline or petrol, jet fuel, kerosene, diesel fuel, and fuel oils...

 and hydrodenitrogenation can address these problems and result in a product comparable to benchmark crude oil. Phenols
Phenols
In organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of a hydroxyl group bonded directly to an aromatic hydrocarbon group...

 can be first be removed by water extraction. Upgrading shale oil into transport fuels requires adjusting hydrogen–carbon ratios by adding hydrogen (hydrocracking) or removing carbon (coking).

Shale oil produced by some technologies, such as the Kiviter process
Kiviter process
-History:The Kiviter process is based on the earlier vertical retort technology . This technology underwent a long process of development...

, can be used without further upgrading as an oil constituent and as a phenolic compound. Distillate oils from the Kiviter process can also be used as diluent
Diluent
A diluent is a diluting agent.Certain fluids are too viscous to be pumped easily or too dense to flow from one particular point to the other. This can be problematic, because it might not be economically feasible to transport such fluids in this state.To ease this restricted movement, diluents...

s for petroleum-originated heavy oils and as an adhesive-enhancing additive in bituminous materials such as asphalt
Asphalt
Asphalt or , also known as bitumen, is a sticky, black and highly viscous liquid or semi-solid that is present in most crude petroleums and in some natural deposits, it is a substance classed as a pitch...

.

Usage


Before World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

, most shale oil was upgraded for use as transport fuels. Afterwards, it was used as a raw material for chemical intermediates, pure chemicals and industrial resins, and as a railroad wood preservative
Preservative
A preservative is a naturally occurring or synthetically produced substance that is added to products such as foods, pharmaceuticals, paints, biological samples, wood, etc. to prevent decomposition by microbial growth or by undesirable chemical changes....

. As of 2008, it is primarily used as a heating oil and marine fuel, and to a lesser extent in the production of various chemicals.

Shale oil's concentration of high-boiling point compounds is suited for the production of middle distillates such as kerosene
Kerosene
Kerosene, sometimes spelled kerosine in scientific and industrial usage, also known as paraffin or paraffin oil in the United Kingdom, Hong Kong, Ireland and South Africa, is a combustible hydrocarbon liquid. The name is derived from Greek keros...

, jet fuel
Jet fuel
Jet fuel is a type of aviation fuel designed for use in aircraft powered by gas-turbine engines. It is clear to straw-colored in appearance. The most commonly used fuels for commercial aviation are Jet A and Jet A-1 which are produced to a standardized international specification...

, and diesel fuel. Additional cracking
Fluid catalytic cracking
Fluid catalytic cracking is the most important conversion process used in petroleum refineries. It is widely used to convert the high-boiling, high-molecular weight hydrocarbon fractions of petroleum crude oils to more valuable gasoline, olefinic gases, and other products...

 can create the lighter hydrocarbons used in gasoline.

Reserves and production



Global technically-recoverable oil shale reserves have recently been estimated at about 2.8 Toilbbl of shale oil, with the largest reserves in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, which is thought to have 1.5 Toilbbl. Worldwide production of shale oil was estimated at 11600 oilbbl/d in 2002. The leading producers were Estonia (5500 oilbbl/d), Brazil (3100 oilbbl/d), and China (2000 oilbbl/d). In 2008, China led production with 470 million liter
Litér
- External links :*...

s (ML), followed by Estonia (445 ML) and Brazil (250 ML).

The production of shale oil has been hindered because of technical difficulties and costs. In March 2011, the United States Bureau of Land Management
Bureau of Land Management
The Bureau of Land Management is an agency within the United States Department of the Interior which administers America's public lands, totaling approximately , or one-eighth of the landmass of the country. The BLM also manages of subsurface mineral estate underlying federal, state and private...

called into question proposals in the U.S. for commercial operations, stating that "There are no economically viable ways yet known to extract and process oil shale for commercial purposes."