Fischer-Tropsch process

Fischer-Tropsch process

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The Fischer–Tropsch process (or Fischer–Tropsch synthesis) is a set of chemical reaction
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....

s that convert a mixture of carbon monoxide
Carbon monoxide
Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...

 and 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...

 into liquid hydrocarbon
Hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....

s. The process, a key component of gas to liquids
Gas to liquids
Gas to liquids is a refinery process to convert natural gas or other gaseous hydrocarbons into longer-chain hydrocarbons such as gasoline or diesel fuel...

 technology, produces a petroleum
Petroleum
Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...

 substitute, typically from coal
Coal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...

, natural gas
Natural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...

, or biomass
Biomass
Biomass, as a renewable energy source, is biological material from living, or recently living organisms. As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel....

 for use as synthetic lubrication oil
Synthetic oil
Synthetic oil is a lubricant consisting of chemical compounds that are artificially made . Synthetic lubricants can be manufactured using chemically modified petroleum components rather than whole crude oil, but can also be synthesized from other raw materials...

 and as synthetic fuel
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 F–T process has received intermittent attention as a source of low-sulfur diesel fuel and to address the supply or cost of petroleum-derived hydrocarbons.

Process chemistry


The Fischer–Tropsch process involves a series of chemical reactions that lead to a variety of hydrocarbons. Useful reactions give alkane
Alkane
Alkanes are chemical compounds that consist only of hydrogen and carbon atoms and are bonded exclusively by single bonds without any cycles...

s: H2 + n CO → CnH(2n+2) + n H2O
where 'n' is a positive integer. The formation of methane (n = 1) is generally unwanted. Most of the alkanes produced tend to be straight-chain alkanes, although some branched alkanes are also formed. In addition to alkane formation, competing reactions result in the formation of alkenes, as well as alcohols and other oxygenated hydrocarbons. Usually, only relatively small quantities of these non-alkane products are formed, although catalysts favoring some of these products have been developed.

Other reactions relevant to the F–T process


Several reactions are required to obtain the gaseous reactants required for F-T catalysis. First, reactant gases entering a F-T reactor must first be desulfurized to protect the catalysts, which are readily poisoned. The other major class of reactions are employed to adjust the H2/CO ratio:
  • water gas shift reaction
    Water gas shift reaction
    The water-gas shift reaction is a chemical reaction in which carbon monoxide reacts with water vapor to form carbon dioxide and hydrogen:The water-gas shift reaction is an important industrial reaction. It is often used in conjunction with steam reforming of methane or other hydrocarbons, which is...

     provides a source of hydrogen:
H2O + CO → H2 + CO2
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

  • For F-T plants that start with methane, another important reaction is steam reforming
    Steam reforming
    Fossil fuel reforming is a method of producing hydrogen or other useful products from fossil fuels such as natural gas. This is achieved in a processing device called a reformer which reacts steam at high temperature with the fossil fuel. The steam methane reformer is widely used in industry to...

    , which converts the methane into CO and H2:
H2O + CH4 → CO + 3 H2

Chemical mechanisms


The conversion of CO to alkanes involves net 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...

 of CO, the hydrogenolysis
Hydrogenolysis
Hydrogenolysis is a chemical reaction whereby a carbon–carbon or carbon–heteroatom single bond is cleaved or undergoes "lysis" by hydrogen. The heteroatom may vary, but it usually is oxygen, nitrogen, or sulfur. A related reaction is hydrogenation, where hydrogen is added to the molecule, without...

 of C-O bonds, and the formation of C-C bonds. Such reactions are assumed to proceed via initial formation of surface-bound metal carbonyl
Metal carbonyl
Metal carbonyls are coordination complexes of transition metals with carbon monoxide ligands. These complexes may be homoleptic, that is containing only CO ligands, such as nickel carbonyl , but more commonly metal carbonyls contain a mix of ligands, such as Re3Cl...

s. The CO ligand
Ligand
In coordination chemistry, a ligand is an ion or molecule that binds to a central metal atom to form a coordination complex. The bonding between metal and ligand generally involves formal donation of one or more of the ligand's electron pairs. The nature of metal-ligand bonding can range from...

 is speculated to undergo dissociation, possibly into oxide and carbide
Carbide
In chemistry, a carbide is a compound composed of carbon and a less electronegative element. Carbides can be generally classified by chemical bonding type as follows: salt-like, covalent compounds, interstitial compounds, and "intermediate" transition metal carbides...

 ligands. Other potential intermediates are various C-1 fragments including formyl (CHO), hydroxycarbene (HCOH), hydroxymethyl (CH2OH), methyl (CH3), methylene (CH2), methylidyne (CH), and hydroxymethylidyne (COH). Furthermore, and critical to the production of liquid fuels, are reactions that form C-C bonds, such as migratory insertion
Migratory insertion
A migratory insertion is a type of reaction in organometallic chemistry wherein two ligands on a metal complex combine. It is a subset of reactions that very closely resembles the insertion reactions, and both are differentiated by the mechanism that leads to the resulting stereochemistry of the...

. Many related stoichiometric reactions have been simulated on discrete metal clusters, but homogeneous F-T catalysts are poorly developed and of no commercial importance.

Process conditions


Generally, the Fischer–Tropsch process is operated in the temperature range of 150–300 °C (302–572 F). Higher temperatures lead to faster reactions and higher conversion rates but also tend to favor methane production. For this reason, the temperature is usually maintained at the low to middle part of the range. Increasing the pressure leads to higher conversion rates and also favors formation of long-chained alkane
Alkane
Alkanes are chemical compounds that consist only of hydrogen and carbon atoms and are bonded exclusively by single bonds without any cycles...

s both of which are desirable. Typical pressures range from one to several tens of atmospheres. Even higher pressures would be favorable, but the benefits may not justify the additional costs of high-pressure equipment, and higher pressures can lead to catalyst deactivation via coke formation.

A variety of synthesis-gas compositions can be used. For cobalt-based catalysts the optimal H2:CO ratio is around 1.8–2.1. Iron-based catalysts promote the water-gas-shift reaction and thus can tolerate lower ratios. This reactivity can be important for synthesis gas derived from coal or biomass, which tend to have relatively low H2:CO ratios (<1).

Product distribution


In general the product distribution of hydrocarbons formed during the Fischer–Tropsch process follows an Anderson-Schulz-Flory distribution, which can be expressed as:
Wn/n = (1-α)2αn-1


Where Wn is the weight fraction of hydrocarbon molecules containing n carbon atoms. α is the chain growth probability or the probability that a molecule will continue reacting to form a longer chain. In general, α is largely determined by the catalyst and the specific process conditions.

Examination of the above equation reveals that methane will always be the largest single product so long as alpha is less than 0.5; however by increasing α close to one, the total amount of methane formed can be minimized compared to the sum of all of the various long-chained products. Increasing α increases the formation of long-chained hydrocarbons. The very long-chained hydrocarbons are waxes, which are solid at room temperature. Therefore, for production of liquid transportation fuels it may be necessary to crack some of the Fischer-Tropsch products. In order to avoid this, some researchers have proposed using zeolites or other catalyst substrates with fixed sized pores that can restrict the formation of hydrocarbons longer than some characteristic size (usually n<10). This way they can drive the reaction so as to minimize methane formation without producing lots of long-chained hydrocarbons. Such efforts have met with only limited success.

Fischer–Tropsch catalysts


A variety of catalysts can be used for the Fischer–Tropsch process, but the most common are the transition metals cobalt, iron, and ruthenium. Nickel can also be used, but tends to favor methane formation ("methanation
Methanation
Methanation is a physical-chemical process to generate Methane from a mixture of various gases out of biomass fermentation or thermo-chemical gasification. The main components are carbon monoxide and hydrogen...

").

Cobalt-based catalysts are highly active, although iron may be more suitable for low-hydrogen-content synthesis gases such as those derived from coal due to its promotion of the water-gas-shift reaction. In addition to the active metal the catalysts typically contain a number of "promoters," including potassium and copper. Group 1 alkali metals, including potassium, are a poison for cobalt catalysts but are promoters for iron catalysts. Catalysts are supported on high-surface-area binders/supports such as silica, alumina, or zeolites. Cobalt catalysts are more active for Fischer-Tropsch synthesis when the feedstock is natural gas. Natural gas has a high hydrogen to carbon ratio, so the water-gas-shift is not needed for cobalt catalysts. Iron catalysts are preferred for lower quality feedstocks such as coal or biomass.

Unlike the other metals used for this process (Co, Ni, Ru), which remain in the metallic state during synthesis, iron catalysts tend to form a number of phases, including various oxides and carbide
Carbide
In chemistry, a carbide is a compound composed of carbon and a less electronegative element. Carbides can be generally classified by chemical bonding type as follows: salt-like, covalent compounds, interstitial compounds, and "intermediate" transition metal carbides...

s during the reaction. Control of these phase transformations can be important in maintaining catalytic activity and preventing breakdown of the catalyst particles.

Fischer–Tropsch catalysts are sensitive to poisoning by sulfur-containing compounds. The sensitivity of the catalyst to sulfur is greater for cobalt-based catalysts than for their iron counterparts.

Promotors also have an important influence on activity. Alkali metal oxides and copper are common promotors, but the formulation depends on the primary metal, iron vs cobalt. Alkali oxides on cobalt catalysts generally cause activity to drop severely even with very low alkali loadings. C5+ and CO2 selectivity increase while methane and C2-C4 selectivity decrease. In addition, the olefin to parafin ratio increases.

LTFT and HTFT


High-temperature Fischer–Tropsch (or HTFT) is operated at temperatures of 330°C-350°C and uses an iron-based catalyst. This process was used extensively by Sasol in their Coal-to-Liquid plants (CTL). Low-Temperature Fischer-Tropsch (LTFT) is operated at lower temperatures and uses a cobalt based catalyst. This process is best known for being used in the first integrated Gas-to-Liquid (GTL) plant operated and built by Shell in Bintulu, Malaysia.

Gasification


F–T plants associated with coal or related solid feedstocks (sources of carbon) must first convert the solid fuel into gaseous reactants, i.e. CO, H2, and alkanes. This conversion is called gasification. Synthesis gas obtained from coal gasification tends to have a H2/CO ratio of ~0.7 compared to the ideal ratio of ~2. This ratio is adjusted via the water-gas shift reaction. Coal-based Fischer–Tropsch plants can produce varying amounts of CO2, depending upon the energy source of the gasification process. However, most coal-based plants rely on the feed coal to supply all the energy requirements of the F-T process. Ongoing research aims to combine biomass gasification (BG) and Fischer-Tropsch (FT) synthesis to produce renewable transportation fuels (biofuel
Biofuel
Biofuel is a type of fuel whose energy is derived from biological carbon fixation. Biofuels include fuels derived from biomass conversion, as well as solid biomass, liquid fuels and various biogases...

s).

History


Since the invention of the original process by Franz Fischer
Franz Joseph Emil Fischer
Franz Joseph Emil Fischer was a German chemist. He and Hans Tropsch discovered the Fischer-Tropsch process. With Hans Schrader he developed the Fischer Assay, a standardized laboratory test for determining the oil yield from oil shale to be expected from a conventional shale oil extraction...

 and Hans Tropsch
Hans Tropsch
Hans Tropsch was a chemist responsible, along with Franz Fischer, for the development of the Fischer-Tropsch process.- Life :...

, working at the Kaiser Wilhelm Institute
Kaiser Wilhelm Institute
The Kaiser Wilhelm Society for the Advancement of Science was a German scientific institution established in 1911. It was implicated in Nazi science, and after the Second World War was wound up and its functions replaced by the Max Planck Society...

 in the 1920s, many refinements and adjustments have been made. The term "Fischer-Tropsch" now applies to a wide variety of similar processes (Fischer-Tropsch synthesis or Fischer-Tropsch chemistry). Fischer and Tropsch filed a number of patents, e.g., US patent no. 1,746,464, applied 1926, published 1930. It was commercialized in Germany in 1936. Being petroleum-poor but coal-rich, Germany used the FT-process during 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...

 to produce ersatz
Ersatz
Ersatz means 'substituting for, and typically inferior in quality to', e.g. 'chicory is ersatz coffee'. It is a German word literally meaning substitute or replacement...

fuels. F-T production accounted for an estimated 9% of German war production of fuels and 25% of the automobile fuel.

The United States Bureau of Mines
United States Bureau of Mines
For most of the 20th century, the U.S. Bureau of Mines was the primary United States Government agency conducting scientific research and disseminating information on the extraction, processing, use, and conservation of mineral resources.- Summary :...

, in a program initiated by the Synthetic Liquid Fuels Act, employed seven Operation Paperclip
Operation Paperclip
Operation Paperclip was the Office of Strategic Services program used to recruit the scientists of Nazi Germany for employment by the United States in the aftermath of World War II...

 synthetic fuel
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...

 scientists in a Fischer-Tropsch plant in Louisiana, Missouri
Louisiana, Missouri
Louisiana is a city in Pike County, Missouri, United States. The population was 3,863 at the 2000 census, making it the largest city in Pike Couunty. Louisiana is located in northeast Missouri, on the Mississippi River south of Hannibal....

 in 1946.

In Britain, Alfred August Aicher obtained several patent
Patent
A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....

s for improvements to the process in the 1930s and 1940s. Aicher's company was named Synthetic Oils Ltd. (Now based in Canada.)

Commercialization



The F–T process has been applied on a large scale in some industrial sectors, although its popularity is hampered by high capital costs, high operation and maintenance costs, the uncertain and volatile price of crude oil, and environmental concerns. In particular, the use of natural gas as a feedstock becomes practical only with use of "stranded gas
Stranded gas reserve
A stranded gas reserve is found in a natural gas field which has been discovered, but remains unusable for either physical or economic reasons. Gas that is found within an oil well is conventionally regarded as associated gas and has historically been flared...

", i.e. sources of natural gas far from major cities which are impractical to exploit with conventional gas pipelines and LNG technology; otherwise, the direct sale of natural gas to consumers would become much more profitable. Several companies are developing the process to enable practical exploitation of so-called stranded gas reserve
Stranded gas reserve
A stranded gas reserve is found in a natural gas field which has been discovered, but remains unusable for either physical or economic reasons. Gas that is found within an oil well is conventionally regarded as associated gas and has historically been flared...

s.

More recently with further discoveries of natural gas and particularly unconventional gas such as shale gas in North America an over supply of gas has developed in North America. This has depressed gas prices. GTL is economically viable when the the gas price is relatively cheap on an energy equivalency basis to oil. Stranded gas provides relatively cheap gas but GTL is now also potentially viable in North America provided gas remains relatively cheaper than oil.

Sasol


The largest scale implementation of F–T technology are in a series of plants operated by Sasol
Sasol
Sasol Ltd. is a South African company involved in mining, energy, chemicals and synfuels. In particular, they produce petrol and diesel profitably from coal and natural gas using Fischer-Tropsch process...

 in South Africa, a country with large coal reserves but little oil. Sasol uses coal and now natural gas as feedstocks and produces a variety of synthetic petroleum products, including most of the country's diesel fuel.

PetroSA


PetroSA (Pty) Ltd, a South African company which, in a joint venture, won project innovation of the year award at the Petroleum Economist Awards in 2008, has the world's largest Gas to Liquids complexes at Mossel Bay in South Africa. The refinery is a 36,000 barrels a day plant that completed semi-commercial demostration in 2011 paving the way to begin commercial preparation. The technology can be used to convert natural gas, biomass or coal into synthetic fuels.

Shell middle distillate synthesis


One of the largest implementations of F-T technology is in Bintulu
Bintulu
Bintulu is a coastal town, and the capital of Bintulu District in the Bintulu Division of Sarawak, Malaysia. It is about 650 kilometers from Kuching and about 215 kilometers from either Sibu or Miri....

, Malaysia. This 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...

 facility converts natural gas
Natural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...

 into low-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...

 diesel fuels and food-grade wax. The scale is 12000 oilbbl/d.

Ras Laffan, Qatar


The new LTFT facility scheduled to commission in 2011 at Ras Laffan, Qatar uses cobalt catalysts at 230 °C, converting natural gas to petroleum liquids at a rate of 140000 oilbbl/d, with additional production of 120000 barrels (19,078.5 m³) of oil equivalent in natural gas liquids and ethane
Ethane
Ethane is a chemical compound with chemical formula C2H6. It is the only two-carbon alkane that is an aliphatic hydrocarbon. At standard temperature and pressure, ethane is a colorless, odorless gas....

. The first GTL plant in Ras Laffan was commissioned in 2007 and is called Oryx GTL and has a capacity of 34 000 bbl/day. The plant utilizes the Sasol slurry phase distillate process which uses a cobalt catalyst. Oryx GTL is a joint venture between Qatar Petroleum and Sasol.

UPM (Finland)


In October 2006, Finnish
Finland
Finland , officially the Republic of Finland, is a Nordic country situated in the Fennoscandian region of Northern Europe. It is bordered by Sweden in the west, Norway in the north and Russia in the east, while Estonia lies to its south across the Gulf of Finland.Around 5.4 million people reside...

 paper and pulp manufacturer UPM
UPM (company)
UPM-Kymmene Corporation is a Finnish pulp, paper and timber manufacturer. UPM-Kymmene was formed by the merger of Kymmene Corporation and Repola Ltd and its subsidiary United Paper Mills Ltd in 1996...

 announced its plans to produce biodiesel by the Fischer–Tropsch process alongside the manufacturing processes at its European paper and pulp plants, using waste biomass resulting from paper and pulp manufacturing processes as source material.

Rentech (Colorado, US)


A demonstration-scale F–T plant is owned and operated by Rentech Inc in partnership with ClearFuels, a company specializing in biomass gasification. Located in Commerce City, Colorado, the facility produces about 10 oilbbl/d of fuels from natural gas. Commercial-scale facilities are planned for Rialto, California
Rialto, California
-2010:The 2010 United States Census reported that Rialto had a population of 99,171. The population density was 4,434.1 people per square mile . The racial makeup of Rialto was 43,592 White, 16,236 African American, 1,062 Native American, 2,258 Asian, 361 Pacific Islander, 30,993 from other...

, Natchez, Mississippi
Natchez, Mississippi
Natchez is the county seat of Adams County, Mississippi, United States. With a total population of 18,464 , it is the largest community and the only incorporated municipality within Adams County...

, Port St. Joe, Florida
Port St. Joe, Florida
Port St. Joe is a city located at the intersection of U.S. Highway 98 and State Road 71 in Gulf County, Florida, United States. As of 2007, the population estimated by the U.S. Census Bureau is 3,579. The population was 3,644 as of the 2000 census. Port St. Joe became the county seat of Gulf County...

, and White River, Ontario
White River, Ontario
White River is a township located in Ontario, Canada, on the intersection of Highway 17 and Highway 631. It was originally set up as a rail town on the Canadian Pacific Railway in 1885...

.

Other


In the US, some coal-producing states have invested in F–T plants. In Pennsylvania, Waste Management and Processors Inc. was funded by the state to implement F–T technology licensed from Shell and Sasol to convert so-called waste coal (leftovers from the mining process) into low-sulfur diesel fuel.

Research developments


Choren Industries has built an F–T plant in Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 that converts biomass to syngas and fuels using the Shell F–T process.

U.S. Air Force certification


Syntroleum
Syntroleum
Syntroleum Corporation is a United States company engaged in development and commercialization of proprietary Gas to liquids and Coal to liquids processes known jointly as the Syntroleum Process.Syntroleum was incorporated in 1984 by Kenneth Agee...

, a publicly traded US company has produced over 400000 gallons (1,514.2 m³) of diesel and jet fuel from the Fischer–Tropsch process using natural gas and coal at its demonstration plant near Tulsa, Oklahoma
Oklahoma
Oklahoma is a state located in the South Central region of the United States of America. With an estimated 3,751,351 residents as of the 2010 census and a land area of 68,667 square miles , Oklahoma is the 28th most populous and 20th-largest state...

. Syntroleum is working to commercialize its licensed Fischer-Tropsch technology via coal-to-liquid plants in the US, China, and Germany, as well as gas-to-liquid plants internationally. Using natural gas as a feedstock, the ultra-clean, low sulfur fuel has been tested extensively by the U.S. Department of Energy and the U.S. Department of Transportation. Most recently, Syntroleum has been working with the U.S. Air Force to develop a synthetic jet fuel blend that will help the Air Force to reduce its dependence on imported petroleum. The Air Force, which is the U.S. military's largest user of fuel, began exploring alternative fuel sources in 1999. On December 15, 2006, a B-52 took off from Edwards AFB, California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

 for the first time powered solely by a 50–50 blend of JP-8
JP-8
JP-8, or JP8 is a jet fuel, specified and used widely by the US military. It is specified by MIL-DTL-83133 and British Defence Standard 91-87, and similar to commercial aviation's Jet-A....

 and Syntroleum's FT fuel. The seven-hour flight test was considered a success. The goal of the flight test program is to qualify the fuel blend for fleet use on the service's B-52s, and then flight test and qualification on other aircraft. The test program concluded in 2007. This program is part of the Department of Defense
United States Department of Defense
The United States Department of Defense is the U.S...

 Assured Fuel Initiative, an effort to develop secure domestic sources for the military energy needs. The Pentagon hopes to reduce its use of crude oil from foreign producers and obtain about half of its aviation fuel from alternative sources by 2016. With the B-52 now approved to use the FT blend, the C-17 Globemaster III
C-17 Globemaster III
The Boeing C-17 Globemaster III is a large military transport aircraft. Developed for the United States Air Force from the 1980s to the early 1990s by McDonnell Douglas, the C-17 is used for rapid strategic airlift of troops and cargo to main operating bases or forward operating bases throughout...

, the B-1B
B-1 Lancer
The Rockwell B-1 LancerThe name "Lancer" is only applied to the B-1B version, after the program was revived. is a four-engine variable-sweep wing strategic bomber used by the United States Air Force...

, and eventually every airframe
Airframe
The airframe of an aircraft is its mechanical structure. It is typically considered to include fuselage, wings and undercarriage and exclude the propulsion system...

 in its inventory to use the fuel by 2011.

Carbon dioxide reuse


In 2009, chemists working for the U.S. Navy investigated Fischer-Tropsch for generating fuels, obtaining hydrogen by electrolysis
Electrolysis
In chemistry and manufacturing, electrolysis is a method of using a direct electric current to drive an otherwise non-spontaneous chemical reaction...

 of seawater
Seawater
Seawater is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% . This means that every kilogram of seawater has approximately of dissolved salts . The average density of seawater at the ocean surface is 1.025 g/ml...

. When it was combined with the dissolved carbon dioxide using a cobalt
Cobalt
Cobalt is a chemical element with symbol Co and atomic number 27. It is found naturally only in chemically combined form. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal....

-based catalyst, the reaction produced mostly methane gas. However, use of an iron-based catalyst allowed reducing the methane produced to 30 per cent with the rest being predominantly short-chain hydrocarbons. Further refining of the hydrocarbons produced by means of solid acid catalysts such as zeolites can potentially lead to the production of 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...

-based jet fuel.

The abundance of makes seawater
Seawater
Seawater is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% . This means that every kilogram of seawater has approximately of dissolved salts . The average density of seawater at the ocean surface is 1.025 g/ml...

 an attractive alternative fuel source. Scientists at the U.S. Naval Research Laboratory stated that, "although the gas forms only a small proportion of air – around 0.04 per cent – ocean water
Seawater
Seawater is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% . This means that every kilogram of seawater has approximately of dissolved salts . The average density of seawater at the ocean surface is 1.025 g/ml...

 contains about 140 times that concentration". Robert Dorner presented the findings of his work to the American Chemical Society
American Chemical Society
The American Chemical Society is a scientific society based in the United States that supports scientific inquiry in the field of chemistry. Founded in 1876 at New York University, the ACS currently has more than 161,000 members at all degree-levels and in all fields of chemistry, chemical...

 on 16 August 2009, in Washington DC. Of course, such a method requires an energy source – since is a major product of combustion, converting it back into combustible material is a highly endothermic
Endothermic
In thermodynamics, the word endothermic describes a process or reaction in which the system absorbs energy from the surroundings in the form of heat. Its etymology stems from the prefix endo- and the Greek word thermasi,...

 (energy-absorbing) process. In practice this would probably come from nuclear power
Nuclear power
Nuclear power is the use of sustained nuclear fission to generate heat and electricity. Nuclear power plants provide about 6% of the world's energy and 13–14% of the world's electricity, with the U.S., France, and Japan together accounting for about 50% of nuclear generated electricity...

, which is in abundant supply aboard nuclear powered ships
Nuclear marine propulsion
Nuclear marine propulsion is propulsion of a ship by a nuclear reactor. Naval nuclear propulsion is propulsion that specifically refers to naval warships...

.

See also


  • Algae fuel
    Algae fuel
    Algae fuel might be an alternative to fossil fuel and uses algae as its source of natural deposits. Several companies and government agencies are funding efforts to reduce capital and operating costs and make algae fuel production commercially viable...

  • Bergius process
    Bergius process
    The Bergius Process is a method of production of liquid hydrocarbons for use as synthetic fuel by hydrogenation of high-volatile bituminous coal at high temperature and pressure...

  • Biogasoline
    Biogasoline
    Biogasoline is gasoline produced from biomass such as algae. Like traditionally produced gasoline, it contains between 6 and 12 carbon atoms per molecule and can be used in internal-combustion engines...

  • Biomass to liquid
    Biomass to liquid
    Biomass to Liquid or BMtL is a multi-step process which produces liquid biofuels from biomass:The process uses the whole plant to improve the carbon dioxide balance and increase yield....

  • Fischer Assay
    Fischer Assay
    The Fischer assay is a standardized laboratory test for determining the oil yield from oil shale to be expected from a conventional shale oil extraction. A 100 gram oil shale sample crushed to...

  • Future energy development
  • 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...

    , a generic term for this type of process
  • Hubbert peak
  • Karrick process
    Karrick process
    The Karrick process is a low-temperature carbonization and pyrolysis process of carbonaceous materials. Although primarily meant for coal carbonization, it also could be used for processing of oil shale, lignite or any carbonaceous materials. These are heated at to in the absence of air to...

  • Synthetic Liquid Fuels Program
    Synthetic Liquid Fuels Program
    The Synthetic Liquid Fuels Program was a program run by the United States Bureau of Mines to create the technology to produce synthetic fuel from coal. It was initiated in 1944 during World War II...

  • Unconventional oil
  • Wood gas
    Wood gas
    Wood gas is a syngas fuel which can be used as a fuel for furnaces, stoves and vehicles in place of petrol, diesel or other fuels. During the production process biomass or other carbon-containing materials is gasified within the oxygen-limited environment of a wood gas generator to produce hydrogen...


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