Editing Fischer–Tropsch process

{{short description|Chemical reactions that convert carbon monoxide and hydrogen into liquid hydrocarbons}}
[[Image:Holzvergaser Güssing.jpg|thumb|right|[[Fluidized bed]] gasification with FT-pilot in [[Güssing]], [[Burgenland]], Austria. Operated by SGCE and [[Velocys]]]]
[[File:Sasol Secunda 19.jpg|thumb|right|[[Sasol]] plant in [[Secunda, South Africa|Secunda]]]]
The '''Fischer–Tropsch process''' (FT) is a collection of [[chemistry|chemical reaction]]s that converts a mixture of [[carbon monoxide]] and [[hydrogen]], known as [[syngas]], into liquid [[hydrocarbon]]s. These reactions occur in the presence of metal [[Heterogeneous catalysis|catalysts]], typically at temperatures of {{convert|150|-|300|C|F}} and pressures of one to several tens of atmospheres. The Fischer–Tropsch process is an important reaction in both [[coal liquefaction]] and [[gas to liquids]] technology for producing liquid hydrocarbons.<ref name="hook">{{cite journal|last1=Höök|first1=Mikael|last2=Fantazzini|first2=Dean|last3=Angelantoni|first3=André|last4=Snowden|first4=Simon|title=Hydrocarbon liquefaction: viability as a peak oil mitigation strategy|journal=Philosophical Transactions of the Royal Society A|date=2013|volume=372|issue=2006|pages=20120319|doi=10.1098/rsta.2012.0319|pmid=24298075|url=http://uu.diva-portal.org/smash/record.jsf?pid=diva2:670680|access-date=2009-06-03|bibcode=2013RSPTA.37220319H|doi-access=free|archive-date=2019-03-28|archive-url=https://web.archive.org/web/20190328191623/http://uu.diva-portal.org/smash/record.jsf?pid=diva2:670680|url-status=live}}</ref>

In the usual implementation, carbon monoxide and hydrogen, the feedstocks for FT, are produced from [[coal]], [[natural gas]], or [[Biomass (energy)|biomass]] in a process known as [[gasification]]. The process then converts these gases into [[synthetic oil|synthetic lubrication oil]] and [[synthetic fuel]].<ref>{{cite web|url=http://tonto.eia.doe.gov/dnav/pet/pet_cons_psup_dc_nus_mbbl_m.htm|title=U.S. Product Supplied for Crude Oil and Petroleum Products|website=tonto.eia.doe.gov|access-date=3 April 2018|archive-url=https://web.archive.org/web/20110228202642/http://tonto.eia.doe.gov/dnav/pet/pet_cons_psup_dc_nus_mbbl_m.htm|archive-date=28 February 2011|url-status=dead|df=dmy-all}}</ref> This process has received intermittent attention as a source of low-sulfur diesel fuel and to address the supply or cost of petroleum-derived hydrocarbons. Fischer–Tropsch process is discussed as a step of producing carbon-neutral liquid hydrocarbon fuels from CO<sub>2</sub> and hydrogen.<ref>Davis, S.J., Lewis, N.S., Shaner, M., Aggarwal, S., Arent, D., Azevedo, I.L., Benson, S.M., Bradley, T., Brouwer, J., Chiang, Y.M. and Clack, C.T., 2018. Net-zero emissions energy systems. Science, 360(6396), p.eaas9793</ref><ref>{{cite journal |doi=10.1021/acsenergylett.2c00214|title=Single-Step Production of Alcohols and Paraffins from CO2 and H2 at Metric Ton Scale |year=2022 |last1=Chen |first1=Chi |last2=Garedew |first2=Mahlet |last3=Sheehan |first3=Stafford W. |journal=ACS Energy Letters |volume=7 |issue=3 |pages=988–992 |s2cid=246930138 |doi-access=free }}</ref><ref>{{Cite web|last=Trakimavicius|first=Lukas|date=December 2023|title=Mission Net-Zero: Charting the Path for E-fuels in the Military|url=https://www.enseccoe.org/publications/mission-net-zero-charting-the-path-for-e-fuels-in-the-military/|publisher=NATO Energy Security Centre of Excellence}}</ref>

The process was first developed by [[Franz Joseph Emil Fischer|Franz Fischer]] and [[Hans Tropsch]] at the [[Kaiser Wilhelm Institute for Coal Research]] in [[Mülheim|Mülheim an der Ruhr]], Germany, in 1925.<ref>{{cite encyclopedia |year=2013 |title=Fischer–Tropsch Process |encyclopedia=Kirk-Othmer Encyclopedia of Chemical Technology |publisher=Wiley-VCH |location=Weinheim |doi=10.1002/0471238961.fiscdekl.a01 |isbn=978-0471238966 |author=Arno de Klerk|pages=1–20 }}</ref>

==Reaction mechanism==
[[image:HCCo3(CO)9.png|thumb|right|144px|[[Methylidynetricobaltnonacarbonyl|Methylidyne&shy;tricobalt&shy;nonacarbonyl]] is a molecule that illustrates the kind of reduced carbon species speculated to occur in the Fischer–Tropsch process.]]
The Fischer–Tropsch process involves a series of chemical reactions that produce a variety of hydrocarbons, ideally having the formula (C<sub>''n''</sub>H<sub>2''n''+2</sub>). The more useful reactions produce [[alkane]]s as follows:<ref name=Dry>{{cite journal |doi=10.1016/S0920-5861(01)00453-9|title=The Fischer–Tropsch process: 1950–2000 |year=2002 |last1=Dry |first1=Mark E. |journal=Catalysis Today |volume=71 |issue=3–4 |pages=227–241 }}</ref>

: (2''n'' + 1)&nbsp;H<sub>2</sub> + ''n''&nbsp;CO → C<sub>''n''</sub>H<sub>2''n''+2</sub> + ''n''&nbsp;H<sub>2</sub>O

where ''n'' is typically 10–20, resulting mostly in the formation of [[higher alkanes]].<ref>{{Cite web |title=Higher alkanes |url=https://www.wartsila.com/encyclopedia/term/higher-alkanes |access-date=2025-05-06 |website=Wartsila.com |language=en}}</ref> The formation of [[methane]] (''n'' = 1) is unwanted. Most of the alkanes produced tend to be straight-chain, suitable as [[diesel fuel]]. In addition to alkane formation, competing reactions give small amounts of [[alkenes]], as well as [[alcohols]] and other oxygenated hydrocarbons.<ref name="Ullmann" />

The reaction is a highly [[exothermic reaction]] due to a standard [[reaction enthalpy]] (ΔH) of −165 kJ/mol CO combined.<ref name="Fratalocchi_2018">{{cite journal|last1=Fratalocchi|first1=Laura|last2=Visconti|first2=Carlo Giorgio|last3=Groppi|first3=Gianpiero|last4=Lietti|first4=Luca|last5=Tronconi|first5=Enrico|title=Intensifying heat transfer in Fischer-Tropsch tubular reactors through the adoption of conductive packed foams|journal=Chemical Engineering Journal|volume=349|year=2018|pages=829–837|issn=1385-8947|doi=10.1016/j.cej.2018.05.108|hdl=11311/1072010|s2cid=103286686|hdl-access=free}}</ref>

===Fischer–Tropsch intermediates and elemental reactions===
Converting a mixture of H<sub>2</sub> and CO into [[Aliphatic compound|aliphatic]] products is a multi-step reaction with several intermediate compounds. The growth of the hydrocarbon chain may be visualized as involving a repeated sequence in which hydrogen atoms are added to carbon and oxygen, the C–O bond is split and a new C–C bond is formed.
For one –CH<sub>2</sub>– group produced by CO + 2&nbsp;H<sub>2</sub> → (CH<sub>2</sub>) + H<sub>2</sub>O, several reactions are necessary:
* Associative adsorption of CO
* Splitting of the C–O bond
* [[Dissociative adsorption]] of 2&nbsp;H<sub>2</sub>
* Transfer of 2&nbsp;H to the oxygen to yield H<sub>2</sub>O
* Desorption of H<sub>2</sub>O
* Transfer of 2&nbsp;H to the carbon to yield CH<sub>2</sub>

The conversion of CO to alkanes involves [[hydrogenation]] of CO, the [[hydrogenolysis]] (cleavage with H<sub>2</sub>) 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]]s. The CO [[ligand]] is speculated to undergo dissociation, possibly into oxide and [[carbide]] ligands.<ref>{{Cite journal |last=Gates |first=Bruce C. |date=February 1993 |title=Extending the Metal Cluster-Metal Surface Analogy |journal=Angewandte Chemie International Edition in English |volume=32 |issue=2 |pages=228–229 |doi=10.1002/anie.199302281}}</ref> Other potential intermediates are various C<sub>1</sub> fragments including [[Transition metal formyl complex|formyl (CHO)]], hydroxycarbene (HCOH), hydroxymethyl (CH<sub>2</sub>OH), [[methyl]] (CH<sub>3</sub>), methylene (CH<sub>2</sub>), [[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]]. Many related stoichiometric reactions have been simulated on discrete [[Cluster chemistry|metal clusters]], but homogeneous Fischer–Tropsch catalysts are of no commercial importance.

Addition of isotopically labelled alcohol to the feed stream results in incorporation of alcohols into product. This observation establishes the facility of C–O bond scission. Using <sup>14</sup>C-labelled [[ethylene]] and [[propene]] over cobalt catalysts results in incorporation of these olefins into the growing chain. Chain growth reaction thus appears to involve both 'olefin insertion' as well as 'CO-insertion'.<ref name="Schultz">{{Cite journal |last=Schulz |first=H. |date=1999 |title=Short history and Present Trends of Fischer-Tropsch Synthesis |journal=Applied Catalysis A: General |volume=186 |issue=1–2 |pages=3–12 |doi=10.1016/S0926-860X(99)00160-X}}</ref>

:<chem>8 CO + 17 H2 -> C8H18 + 8 H2O</chem>

==Feedstocks: gasification==
[[File:Krupp-Treibstoffwerk Wanne-Eickel um 1953.jpg|thumb|right|Krupp-Treibstoffwerk Wanne-Eickel in 1953]]

Fischer–Tropsch plants associated with [[biomass]] or coal or related solid feedstocks (sources of carbon) must first convert the solid fuel into gases. These gases include CO, H<sub>2</sub>, and alkanes. This conversion is called [[gasification]].<ref>{{Cite journal |last=Sasidhar |first=Nallapaneni |date=November 2023 |title=Carbon Neutral Fuels and Chemicals from Standalone Biomass Refineries |url=https://www.ijee.latticescipub.com/wp-content/uploads/papers/v3i2/B1845113223.pdf |access-date=3 December 2023 |journal=Indian Journal of Environment Engineering |issn=2582-9289 |volume=3 |issue=2|pages=1–8 |doi=10.54105/ijee.B1845.113223 |s2cid=265385618}}</ref> [[Synthesis gas]] ("syngas") is obtained from biomass/coal gasification is a mixture of hydrogen and carbon monoxide. The H<sub>2</sub>:CO ratio is adjusted using the [[water-gas shift reaction]]. Coal-based FT plants produce varying amounts of CO<sub>2</sub>, 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 process.

===Feedstocks: GTL===
Carbon monoxide for FT catalysis is derived from hydrocarbons. In [[gas to liquids]] (GTL) technology, the hydrocarbons are low molecular weight materials that often would be discarded or flared. Stranded gas provides relatively cheap gas. For GTL to be commercially viable, gas must remain relatively cheaper than oil.

Several reactions are required to obtain the gaseous reactants required for FT [[catalysis]]. First, reactant gases entering a reactor must be [[desulfurization|desulfurized]]. Otherwise, sulfur-containing impurities deactivate ("[[Catalyst poisoning|poison]]") the [[catalyst]]s required for FT reactions.<ref name="Ullmann">{{Cite book |title=Ullmann's Encyclopedia of Industrial Chemistry |last1=Kaneko |first1=Takao |last2=Derbyshire |first2=Frank |last3=Makino |first3=Eiichiro |last4=Gray |first4=David |last5=Tamura |first5=Masaaki |date=2001 |publisher=Wiley-VCH |isbn=9783527306732 |location=Weinheim |chapter=Coal Liquefaction |doi=10.1002/14356007.a07_197}}</ref><ref name=Dry/>

Several reactions are employed to adjust the H<sub>2</sub>:CO ratio. Most important is the [[water-gas shift reaction]], which provides a source of [[hydrogen]] at the expense of carbon monoxide:<ref name="Ullmann" />
:<chem>H2O + CO -> H2 + CO2</chem>
For FT plants that use [[methane]] as the [[raw material|feedstock]], another important reaction is [[Carbon dioxide reforming|dry reforming]], which converts the methane into CO and H<sub>2</sub>:
: <chem>CH4 + CO2 -> 2CO + 2H2</chem>

===Process conditions===
[[File:Sample Shell GTL Fuel (duty free version).JPG|thumb|right|A sample of Shell GTL Fuel]]

Generally, the Fischer–Tropsch process is operated in the temperature range of {{convert|150|-|300|C|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 the formation of long-chained [[alkane]]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 (fuel)|coke]] formation.

A variety of synthesis-gas compositions can be used. For cobalt-based catalysts the optimal H<sub>2</sub>:CO ratio is around 1.8–2.1. [[Iron]]-based catalysts can tolerate lower ratios, due to their intrinsic [[water-gas shift reaction]] activity. This reactivity can be important for synthesis gas derived from coal or biomass, which tend to have relatively low H<sub>2</sub>:CO ratios (<&nbsp;1).

=== Design of the Fischer–Tropsch process reactor ===
Efficient removal of heat from the reactor is the basic need of FT reactors since these reactions are characterized by high exothermicity. Four types of reactors are discussed:

====Multi tubular fixed-bed reactor====
[[File:Fischer Tropsch Reaktor Ruhrchemie 1946 b.jpg|thumb|right|A 1946 publicity showing the innards of the [[Ruhrchemie]] Fischer-Tropsch reactor]]
: This type of reactor contains several tubes with small diameters. These tubes contain catalysts and are surrounded by cooling water which removes the heat of the reaction. A fixed-bed reactor is suitable for operation at low temperatures and has an upper-temperature limit of 257&nbsp;°C (530&nbsp;K). Excess temperature leads to carbon deposition and hence blockage of the reactor. Since large amounts of the products formed are in liquid state, this type of reactor can also be referred to as a trickle flow reactor system.

====Entrained flow reactor====
:This type of reactor contains two banks of heat exchangers which remove heat; the remainder of which is removed by the products and recycled in the system. The formation of heavy waxes should be avoided, since they condense on the catalyst and form agglomerations. This leads to fluidization. Hence, risers are operated over 297&nbsp;°C (570&nbsp;K).

====Slurry reactors====
:Heat removal is done by internal cooling coils. The synthesis gas is bubbled through the waxy products and finely-divided catalyst which is suspended in the liquid medium. This also provides agitation of the contents of the reactor. The catalyst particle size reduces diffusional heat and mass transfer limitations. A lower temperature in the reactor leads to a more viscous product and a higher temperature (>&nbsp;297&nbsp;°C, 570&nbsp;K) gives an undesirable product spectrum. Also, separation of the product from the catalyst is a problem.

====Fluid-bed and circulating catalyst (riser) reactors====
:These are used for high-temperature FT synthesis (nearly 340&nbsp;°C) to produce low-molecular-weight unsaturated hydrocarbons on alkalized fused iron catalysts. The fluid-bed technology (as adapted from the catalytic cracking of heavy petroleum distillates) was introduced by Hydrocarbon Research in 1946–50 and named the 'Hydrocol' process. A large scale Fischer–Tropsch Hydrocol plant (350,000 tons per annum) operated during 1951–57 in Brownsville, Texas. Due to technical problems, and impractical economics due to increasing petroleum availability, this development was discontinued. Fluid-bed FT synthesis has been reinvestigated by [[Sasol]]. One reactor with a capacity of 500,000 tons per annum is in operation. The process has been used for C<sub>2</sub> and C<sub>7</sub> alkene production. A high-temperature process with a circulating iron catalyst ('circulating fluid bed', 'riser reactor', 'entrained catalyst process') was introduced by the Kellogg Company and a respective plant built at Sasol in 1956. It was improved by Sasol for successful operation. At Secunda, South Africa, Sasol operated 16 advanced reactors of this type with a capacity of approximately 330,000 tons per annum each. The circulating catalyst process can be replaced by fluid-bed technology. Early experiments with cobalt catalyst particles suspended in oil have been performed by Fischer. The bubble column reactor with a powdered iron slurry catalyst and a CO-rich syngas was particularly developed to pilot plant scale by Kölbel at the Rheinpreuben Company in 1953. Since 1990, low-temperature FT slurry processes are under investigation for the use of iron and cobalt catalysts, particularly for the production of a hydrocarbon wax, or to be hydrocracked and isomerized to produce diesel fuel, by Exxon and Sasol. Slurry-phase (bubble column) low-temperature FT synthesis is efficient. This technology is also under development by the Statoil Company (Norway) for use on a vessel to convert associated gas at offshore oil fields into a hydrocarbon liquid.<ref>{{Cite book |title=Chemical Process Technology |last1=Moulijn |first1=Jacob A. |last2=Makkee |first2=Michiel |last3=van Diepen |first3=Annelies E. |date=May 2013 |publisher=Wiley |isbn=978-1-4443-2025-1 |pages=193–200}}</ref>

===Product distribution===
In general the product distribution of hydrocarbons formed during the Fischer–Tropsch process follows an [[Anderson–Schulz–Flory distribution]],<ref>{{Cite web |url=http://www.fischer-tropsch.org/DOE/DOE_reports/510/510-34929/510-34929.pdf |title=Preliminary Screening — Technical and Economic Assessment of Synthesis Gas to Fuels and Chemicals with Emphasis on the Potential for Biomass-Derived Syngas |last1=Spath |first1=P. L. |last2=Dayton |first2=D. C. |date=December 2003 |work=NREL/TP510-34929 |publisher=National Renewable Energy Laboratory |page=95 |archive-url=https://web.archive.org/web/20081217093857/http://www.fischer-tropsch.org/DOE/DOE_reports/510/510-34929/510-34929.pdf |archive-date=2008-12-17 |url-status=dead |access-date=2008-06-12}}</ref> which can be expressed as:

: {{sfrac|''W''<sub>''n''</sub>|''n''}} = (1 − ''α'')<sup>2</sup>''α''<sup>''n''−1</sup>

where ''W''<sub>''n''</sub> is the weight fraction of hydrocarbons containing ''n'' carbon atoms, and ''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 ''α'' 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 FT 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''&nbsp;<&nbsp;10). This way they can drive the reaction so as to minimize methane formation without producing many long-chained hydrocarbons. Such efforts have had only limited success.

==Catalysts==
[[File:Franz Josef Emil Fischer - 1877 reutsche.jpg|thumb|right|Franz Josef Emil Fischer - 1877]]
Four metals are active as [[catalyst]]s for the Fischer–Tropsch process: iron, cobalt, nickel, and ruthenium. Since FT process typically transforms inexpensive precursors into complex mixtures that require further refining, FT catalysts are based on inexpensive metals, especially iron and cobalt.<ref>{{cite book |doi=10.1002/14356007.o05_o03|chapter=Heterogeneous Catalysis and Solid Catalysts, 3. Industrial Applications |title=Ullmann's Encyclopedia of Industrial Chemistry |year=2011 |last1=Deutschmann |first1=Olaf |last2=Knözinger |first2=Helmut |last3=Kochloefl |first3=Karl |last4=Turek |first4=Thomas |isbn=978-3527306732 }}</ref><ref name= Khodakov/> Nickel generates too much methane, so it is not used.<ref name=Dry/>

Typically, such [[heterogeneous catalyst]]s are obtained through precipitation from iron nitrate solutions. Such solutions can be used to deposit the metal salt onto the [[catalyst support]] (see below). Such treated materials transform into active catalysts by heating under CO, H<sub>2</sub> or with the feedstock to be treated, i.e., the catalysts are generated in situ. Owing to the multistep nature of the FT process, analysis of the catalytically active species is challenging. Furthermore, as is known for iron catalysts, a number of phases may coexist and may participate in diverse steps in the reaction. Such phases include various oxides and [[carbide]]s as well as [[Polymorphism (materials science)|polymorph]]s of the metals. Control of these constituents may be relevant to product distributions. Aside from iron and cobalt, nickel and ruthenium are active for converting the CO/H<sub>2</sub> mixture to hydrocarbons.<ref name="Schultz" /> Although expensive, [[ruthenium]] is the most active of the Fischer–Tropsch catalysts in the sense that It works at the lowest reaction temperatures and produces higher molecular weight hydrocarbons. Ruthenium catalysts consist of the metal, without any promoters, thus providing relatively simple system suitable for mechanistic analysis. Its high price preclude industrial applications. Cobalt catalysts are more active for FT 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. Cobalt-based catalysts are more sensitive than their iron counterparts.

Illustrative of real world catalyst selection, high-temperature Fischer–Tropsch (HTFT), which operates at 330–350&nbsp;°C, uses an iron-based catalyst. This process was used extensively by [[Sasol]] in their [[Coal-to-liquids|coal-to-liquid]] plants (CTL). Low-temperature Fischer–Tropsch (LTFT) uses an iron- or cobalt-based catalyst. This process is best known for being used in the first integrated GTL-plant operated and built by [[Royal Dutch Shell|Shell]] in [[Bintulu]], Malaysia.<ref>{{cite web|url=https://www.scribd.com/doc/3825160/Gas-to-Liquids-GTL-Technology|title=Gas to Liquids (GTL) Technology|access-date=15 May 2015|archive-date=16 April 2015|archive-url=https://web.archive.org/web/20150416151901/https://www.scribd.com/doc/3825160/Gas-to-Liquids-GTL-Technology|url-status=live}}</ref>

===Promoters and supports===
In addition to the active metal (usually Fe or Co), two other components comprise the catalyst: promoters and the [[catalyst support]]. Promoters are additives that enhance the behavior of the catalyst. For F-T catalysts, typical promoters including potassium and copper, which are usually added as salts. The choice of promoters depends on the primary metal, iron vs cobalt.<ref name="ReferenceB">{{Cite journal |last1=Balonek |first1=Christine M. |last2=Lillebø |first2=Andreas H. |last3=Rane |first3=Shreyas |last4=Rytter |first4=Erling |last5=Schmidt |first5=Lanny D. |last6=Holmen |first6=Anders |date=2010-08-01 |title=Effect of Alkali Metal Impurities on Co–Re Catalysts for Fischer–Tropsch Synthesis from Biomass-Derived Syngas  |journal=[[Catalysis Letters]] |language=en |volume=138 |issue=1–2 |pages=8–13 |doi=10.1007/s10562-010-0366-4 |s2cid=98234730 |issn=1011-372X}}</ref> Iron catalysts need alkali promotion to attain high activity and stability (e.g. 0.5 wt% {{chem2|K2O}}). Potassium-doped α-Fe<sub>2</sub>O<sub>3</sub> are synthesized under variable calcination temperatures (400–800&nbsp;°C).<ref>{{Cite journal |last1=Hoque |first1=Md Ariful |last2=Guzman |first2=Marcelo I. |last3=Selegue |first3=John P. |last4=Gnanamani |first4=Muthu Kumaran |date=2022-10-21 |title=Chemical State of Potassium on the Surface of Iron Oxides: Effects of Potassium Precursor Concentration and Calcination Temperature |journal=Materials |volume=15 |issue=20 |pages=7378 |doi=10.3390/ma15207378 |doi-access=free |issn=1996-1944 |pmc=9610504 |pmid=36295443|bibcode=2022Mate...15.7378H }}</ref> Addition of Cu for reduction promotion, addition of {{chem|Si|O|2}}, {{chem|Al|2|O|3}} for structural promotion and maybe some manganese can be applied for selectivity control (e.g. high olefinicity). The choice of promoters depends on the primary metal, i.e., iron vs cobalt.<ref name="ReferenceB"/> While group 1 alkali metals (e.g., potassium), help iron catalysts, they poison cobalt catalysts.

Catalysts are supported on high-surface-area binders/supports such as [[silica]], [[alumina]], or [[zeolites]].<ref name= Khodakov>{{Cite journal |last1=Khodakov |first1=Andrei Y. |last2=Chu |first2=Wei |last3=Fongarland |first3=Pascal |date=2007-05-01 |title=Advances in the Development of Novel Cobalt Fischer−Tropsch Catalysts for Synthesis of Long-Chain Hydrocarbons and Clean Fuels |journal=[[Chemical Reviews]] |volume=107 |issue=5 |pages=1692–1744 |doi=10.1021/cr050972v |pmid=17488058 |issn=0009-2665}}</ref>
<!--The working catalyst is only obtained when—after reduction with hydrogen—in the initial period of synthesis several iron carbide phases and elemental carbon are formed whereas iron oxides are still present in addition to some metallic iron. With iron catalysts two directions of selectivity have been pursued. One direction has aimed at a low-molecular-weight olefinic hydrocarbon mixture to be produced in an entrained phase or fluid bed process (Sasol–Synthol process). Due to the relatively high reaction temperature (approx. 340&nbsp;°C), the average molecular weight of the product is so low that no liquid product phase occurs under reaction conditions.

The catalyst particles in the reactor are small (diameter 100&nbsp;μm) and carbon deposition on the catalyst does not disturb reactor operation. Thus, a low catalyst porosity with small pore diameters as obtained from fused magnetite (plus promoters) after reduction with hydrogen is appropriate. For maximising the overall gasoline yield, C<sub>3</sub> and C<sub>4</sub> alkenes have been oligomerized at Sasol. However, recovering the olefins for use as chemicals in, e.g., polymerization processes is advantageous. The second direction of iron catalyst development has aimed at highest catalyst activity to be used at low reaction temperature where most of the hydrocarbon product is in the liquid phase under reaction conditions.  The main product fraction then is a [[paraffin wax]], which is refined to marketable wax materials at Sasol; however, it also can be very selectively [[hydrocracked]] to a high quality diesel fuel. Thus, iron catalysts are very flexible.-->

==History==
[[File:Max-Planck-Institut für Kohlenforschung.jpg|thumb|right|Max Planck Institute for Coal Research at Mülheim an der Ruhr, Germany.]]
The F-T process attracted attention as a means of [[Nazi Germany]] to produce liquid hydrocarbons. The original process was developed by [[Franz Joseph Emil Fischer|Franz Fischer]] and [[Hans Tropsch]], working at the [[Kaiser Wilhelm Society|Kaiser-Wilhelm-Institut for Chemistry]] in 1926. They filed a number of patents, ''e.g.'', {{US patent|1,746,464}}, applied 1926, published 1930.<ref>{{cite patent |country=US |number=1746464|gdate=1930-02-11}}</ref> It was commercialized by [[Brabag]] in Germany in 1936. Being petroleum-poor but coal-rich, Germany used the process during [[World War II]] to produce ''[[ersatz]]'' (replacement) fuels. FT production accounted for an estimated 9% of German war production of fuels and 25% of the automobile fuel.<ref name="Leckel">{{Cite journal |last=Leckel |first=Dieter |date=2009-05-21 |title=Diesel Production from Fischer−Tropsch: The Past, the Present, and New Concepts  |journal=[[Energy & Fuels]] |volume=23 |issue=5 |pages=2342–2358 |doi=10.1021/ef900064c |issn=0887-0624}}</ref> Many refinements and adjustments have been made to the process since Fischer and Tropsch's time.

The [[United States Bureau of Mines]], in a program initiated by the [[Synthetic Liquid Fuels Program|Synthetic Liquid Fuels Act]], employed seven [[Operation Paperclip]] [[synthetic fuel]] scientists in a Fischer–Tropsch plant in [[Louisiana, Missouri]] in 1946.<ref name=Leckel/><ref>{{cite web|url=http://www.fischer-tropsch.org/primary_documents/presentations/ft_ww2/ft_ww2_slide33.htm|title=German Synthetic Fuels Scientists|access-date=15 May 2015|url-status=dead|archive-url=https://web.archive.org/web/20150924013714/http://www.fischer-tropsch.org/primary_documents/presentations/ft_ww2/ft_ww2_slide33.htm|archive-date=24 September 2015}}</ref>

In Britain, Alfred August Aicher obtained several [[patent]]s for improvements to the process in the 1930s and 1940s.<ref>For example, British Patent No. 573,982, applied 1941, published 1945{{cite web |title=Improvements in or relating to Methods of Producing Hydrocarbon Oils from Gaseous Mixtures of Hydrogen and Carbon Monoxide |url=http://www.fischer-tropsch.org/primary_documents/patents/GB/gb573982.pdf |date=January 14, 1941 |access-date=2008-11-09 |url-status=dead |archive-url=https://web.archive.org/web/20081217093903/http://www.fischer-tropsch.org/primary_documents/patents/GB/gb573982.pdf |archive-date=December 17, 2008 }}</ref> Aicher's company was named ''Synthetic Oils Ltd'' (not related to a company of the same name in Canada).{{citation needed|date=October 2015}}

Around the 1930s and 1940s, Arthur Imhausen developed and implemented an industrial process for producing edible fats from these synthetic oils through [[Paraffin oxidation|oxidation]].<ref name="Imha1943">{{cite journal | last1 = Imhausen | first1 = Arthur | year = 1943 | title = Die Fettsäure-Synthese und ihre Bedeutung für die Sicherung der deutschen Fettversorgung. | journal = Kolloid-Zeitschrift | volume = 103 | issue = 2 | pages = 105–108 | doi = 10.1007/BF01502087 | s2cid = 93119728 }}</ref> The products were fractionally distilled and the edible fats were obtained from the {{chem|C|9}}-{{chem|C|16}} fraction<ref name="Whit1951">{{cite book |title=Organic Chemistry |last=Whitmore |first=Frank C. |year=1951 |publisher=Dover Publications Inc. |page=256}}</ref> which were reacted with [[glycerol]] such as that synthesized from propylene.<ref name="Chem1946" /> [[Margarine#Coal butter|"Coal butter"]] margarine made from synthetic oils was found to be nutritious and of agreeable taste, and it was incorporated into diets contributing as much as 700 calories per day.<ref name="Maie2016">{{cite magazine |title=Coal-in Liquid Form |first=Elke |last=Maier |magazine=Max Planck Research |publisher=Max-Planck-Gesellschaft |date=April 2016 |url=https://www.mpg.de/10856815/S004_Flashback_078-079.pdf |pages=78–79 |access-date=2019-12-19 |archive-date=2020-11-01 |archive-url=https://web.archive.org/web/20201101234423/https://www.mpg.de/10856815/S004_Flashback_078-079.pdf |url-status=live }}</ref><ref name="Ihde1964">{{cite book |title=The Development of Modern Chemistry |first=Aaron J. |last=Ihde |publisher=Harper & Row |year=1964 |page=683}}</ref> The process required at least 60&nbsp;kg of coal per kg of synthetic butter.<ref name="Chem1946">{{cite journal |title=Synthetic Soap and Edible Fats |journal=Chemical Age |volume=54 |year=1946 |page=308}}</ref>

==Commercialization==
===Uzbekistan GTL===
[[File:The GTL plant in Qashqadaryo, Tashkent.jpg|thumb|right|The GTL plant in [[Qashqadaryo Region|Qashqadaryo]], [[Tashkent]]]]
{{main|Uzbekistan GTL}}
===Ras Laffan, Qatar===
{{main|Oryx GTL}}
The LTFT facility [[Pearl GTL]] at [[Ras Laffan]], Qatar, is the second largest FT plant in the world after [[Sasol]]'s Secunda plant in South Africa. It uses [[cobalt]] catalysts at 230&nbsp;°C, converting natural gas to petroleum liquids at a rate of {{convert|140000|oilbbl/d|m3/d}}, with additional production of {{convert|120000|oilbbl|m3}} of oil equivalent in [[natural gas liquids]] and [[ethane]].

Another plant in Ras Laffan, called Oryx GTL, has been commissioned in 2007 with a capacity of {{convert|34000|oilbbl/day|m3/d}}. The plant utilizes the Sasol slurry phase distillate process, which uses a cobalt catalyst. Oryx GTL is a joint venture between [[QatarEnergy]] and [[Sasol]].<ref name=C1>{{cite journal|title=A Selection of Recent Advances in C1 Chemistry|author=Carl Mesters|year=2016|volume=7|pages=223–38|journal=Annual Review of Chemical and Biomolecular Engineering|doi=10.1146/annurev-chembioeng-080615-034616|pmid=27276549}}</ref>

===Sasol===
[[File:Sasol CTL, Secunda.jpg|thumb|right|Secunda CTL is a synthetic fuel plant owned by Sasol at [[Secunda, Mpumalanga]] in [[South Africa]]. It uses coal liquefaction to produce petroleum-like [[synthetic crude oil]] from coal.]]
{{Main|Sasol}}
The world's largest scale implementation of Fischer–Tropsch technology is a series of plants operated by [[Sasol]] in [[South Africa]], a country with large coal reserves, but little oil. With a capacity of 165000 Bpd at its [[Secunda CTL]] plant.<ref name=jcza1>{{Cite journal|last1=Meleloe K.E.|last2=Walwyn D.R.|date=2016-09-01|title=Success factors for the commercialisation of Gas-to-Liquids technology|url=https://journals.co.za/doi/abs/10.10520/EJC194106|journal=South African Journal of Business Management|volume=47|issue=3|pages=63–72|doi=10.4102/sajbm.v47i3.69 |hdl=10520/EJC194106 |hdl-access=free}}</ref> The first commercial plant opened in 1952.<ref>[https://books.google.com/books?id=8dwDAAAAMBAJ&pg=PA264 "Construction of World's First Synthesis Plant"] {{Webarchive|url=https://web.archive.org/web/20220429174152/https://books.google.com/books?id=8dwDAAAAMBAJ&pg=PA264 |date=2022-04-29 }} ''Popular Mechanics'', February 1952, p. 264, bottom of page.</ref> Sasol uses coal and natural gas as feedstocks and produces a variety of synthetic petroleum products, including most of the country's [[diesel fuel]].<ref>[http://www.sasol.com/sasol_internet/frontend/navigation.jsp?navid=1600033&rootid=2 "technologies & processes" Sasol]  {{webarchive|url=https://web.archive.org/web/20081116015532/http://www.sasol.com/sasol_internet/frontend/navigation.jsp?navid=1600033&rootid=2 |date=2008-11-16 }}</ref>

===PetroSA===
[[PetroSA]], another South African company, operates a refinery with a 36,000 barrels a day plant that completed semi-commercial demonstration in 2011, paving the way to begin commercial preparation. The technology can be used to convert natural gas, biomass or coal into synthetic fuels.<ref>{{cite web |url=http://www.businessday.co.za/articles/Content.aspx?id=142267 |title=PetroSA technology ready for next stage &#124; Archive &#124; BDlive |publisher=Businessday.co.za |date=2011-05-10 |access-date=2013-06-05 |archive-date=2012-04-03 |archive-url=https://web.archive.org/web/20120403040040/http://www.businessday.co.za/articles/Content.aspx?id=142267 |url-status=live }}</ref>

===Shell middle distillate synthesis===
One of the largest implementations of Fischer–Tropsch technology is in [[Bintulu]], Malaysia. This [[Royal Dutch Shell|Shell]] facility converts [[natural gas]] into low-[[sulfur]] [[Diesel fuel]]s and food-grade wax. The scale is {{convert|12000|oilbbl/d|m3/d}}.

===Velocys===
Velocys operated a demonstration plant with Envia in Oklahoma City during 2017 and 2018.  The Joint Venture was closed down and reactors returned to Velocys [https://biomassmagazine.com/articles/velocys-announces-close-out-of-envia-joint-venture-16128 after the site was sold to another joint venture partner for $4.15 million].

The company's Fischer-Tropsch reactors were used by TOYO Engineering Corporation to produce sustainable aviation fuel (SAF) from woodchips at its demonstration plant in Nagoya, Japan in 2020. [https://bioenergyinternational.com/japan-first-with-commercial-flight-to-use-saf-derived-from-gasified-woodchips/ The produced fuel was used in flight JL 515 from Tokyo to Sapporo on June 17, 2021], marking the first time aviation fuel derived from gasified woodchips and synthesized into SAF was used in a commercial flight.
===SGCE===
Starting as a biomass technology licensor <ref>{{cite news|url=https://www.biofuelsdigest.com/bdigest/2011/04/25/frontline-bioenergy-completes-series-b-financing-gasifier-partnership-with-sgc-energia/|title=Frontline Bioenergy completes Series B financing, gasifier partnership with SGC Energia|date=April 2011|access-date=2022-01-03|archive-date=2022-01-03|archive-url=https://web.archive.org/web/20220103073433/https://www.biofuelsdigest.com/bdigest/2011/04/25/frontline-bioenergy-completes-series-b-financing-gasifier-partnership-with-sgc-energia/|url-status=live}}</ref> In Summer of 2012 SGC Energia (SGCE) successfully commissioned a pilot multi tubular Fischer–Tropsch process unit and associated product upgrading units at the Pasadena, Tx Technology Center. The technology center focused on the development and operations of their XTLH solution which optimized processing of low value carbon waste streams into advanced fuels and wax products.<ref>{{cite news|url=https://www.aiche.org/conferences/aiche-spring-meeting-and-global-congress-on-process-safety/2013/proceeding/paper/54b-successful-operation-1-bpd-fischer-tropsch-pilot-plant-2|title=Successful Operation of a 1 BPD Fischer Tropsch Pilot Plant|publisher=AICHE|date=April 2013|access-date=2022-01-03|archive-date=2022-01-03|archive-url=https://web.archive.org/web/20220103071615/https://www.aiche.org/conferences/aiche-spring-meeting-and-global-congress-on-process-safety/2013/proceeding/paper/54b-successful-operation-1-bpd-fischer-tropsch-pilot-plant-2|url-status=live}}</ref> This unit also serves as an operations training environment for the 1100 BPD [[Juniper GTL]] facility constructed in [[Westlake LA]].

===UPM (Finland)===
In October 2006, [[Finland|Finnish]] paper and pulp manufacturer [[UPM (company)|UPM]] 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.<ref name=upm1>{{cite news|archive-url=https://web.archive.org/web/20070317104947/http://newsroom.finland.fi/stt/showarticle.asp?intNWSAID=14179&group=Business |title=UPM-Kymmene says to establish beachhead in biodiesel market |publisher=NewsRoom Finland |archive-date=2007-03-17 |url=http://newsroom.finland.fi/stt/showarticle.asp?intNWSAID=14179&group=Business |url-status=dead}}</ref>

===Arcadia eFuels===
Texas based Arcadia eFuels in conjunction with Sasol and [[Topsoe]] is constructing a sustainable aviation fuel plant in [[Vordingborg|Vordingborg, Denmark]] that will use Fischer-Tropsch process to convert [[syngas]] derived from [[water electrolysis]] and [[Carbon capture and storage|carbon capture]] into an e-diesel fuel for [[aviation]].<ref name=gcc1>{{Cite web |title=Arcadia eFuels selects Plug Power for 280 MW PEM electrolyzer system for SAF production at Vordingborg |url=https://www.greencarcongress.com/2023/10/20231012-arcadia.html |access-date=2025-01-20 |website=Green Car Congress}}</ref><ref>{{Cite web |last=Brelsford |first=Robert |date=2023-02-20 |title=Denmark-based operator lets contract for first-of-a-kind electrofuels plant |url=https://www.ogj.com/energy-transition/article/14290070/denmark-based-operator-lets-contract-for-first-of-a-kind-electrofuels-plant |access-date=2025-01-20 |website=Oil & Gas Journal |language=en}}</ref> The plant will begin production in 2028 with additional plants in development in [[Teesside|Teesside, United Kingdom]] and the United States.<ref>{{Cite web |date=2024-10-02 |title=Arcadia hit by delay: Won't be able to deliver green aviation fuels until 2028 |url=https://energywatch.com/EnergyNews/Cleantech/article17501728.ece |access-date=2025-01-20 |website=energywatch.com |language=en}}</ref><ref>{{Cite web |title=Industry Insights: Arcadia eFuels |url=https://www.sashacoalition.org/blog/industry-insights-arcadia-efuels |access-date=2025-01-20 |website=SASHA Coalition |language=en-GB}}</ref>

===Rentech===
A demonstration-scale Fischer–Tropsch plant was built and operated by Rentech, Inc., in partnership with ClearFuels, a company specializing in biomass gasification. Located in [[Commerce City CO]], the facility produces about {{convert|10|oilbbl/d|m3/d}} of fuels from natural gas. Commercial-scale facilities were planned for [[Rialto, California]]; [[Natchez, Mississippi]]; [[Port St. Joe, Florida]]; and [[White River, Ontario]].<ref name=ren1>http://www.rentechinc.com/ {{Webarchive|url=https://web.archive.org/web/20101127142221/http://rentechinc.com/ |date=2010-11-27 }} (official site)</ref> Rentech closed down their pilot plant in 2013, and abandoned work on their FT process as well as the proposed commercial facilities.

=== INFRA GTL Technology ===
[[File:INFRA M100 GTL Plant.jpg|thumb|right|INFRA M100 Gas-To-Liquid Plant near [[Houston]], TX]]
In 2010, [[INFRA]] built a compact Pilot [http://en.infratechnology.com/technology/pilotplant/ Plant] for conversion of natural gas into synthetic oil. The plant modeled the full cycle of the GTL chemical process including the intake of pipeline gas, sulfur removal, steam methane reforming, syngas conditioning, and Fischer–Tropsch synthesis. In 2013 the first pilot plant was acquired by VNIIGAZ [[Gazprom]] LLC. In 2014 INFRA commissioned and operated on a continuous basis a new, larger scale full cycle Pilot Plant. It represents the second generation of INFRA's testing facility and is differentiated by a high degree of automation and extensive data gathering system. In 2015, INFRA built its own catalyst factory in [[Troitsk]] (Moscow, Russia). The catalyst factory has a capacity of over 15 tons per year, and produces the unique proprietary Fischer–Tropsch catalysts developed by the company's R&D division. In 2016, INFRA designed and built a modular, transportable GTL (gas-to-liquid) M100 plant for processing natural and associated gas into [[synthetic crude oil]] in [[Wharton TX]]. The M100 plant is operating as a technology demonstration unit, R&D platform for catalyst refinement, and economic model to scale the Infra GTL process into larger and more efficient plants.<ref name=geo1>{{Cite web|url=https://assets.geoexpro.com/uploads/f5fee307-f77c-4a44-bc96-b31f1ff05ee8/GEO_ExPro_v14i4.pdf|title=GEO ExPro magazine|website=Vol. 14, No. 4 – 2017 Pgs 14-17|access-date=2018-08-27|archive-date=2018-08-21|archive-url=https://web.archive.org/web/20180821223154/https://assets.geoexpro.com/uploads/f5fee307-f77c-4a44-bc96-b31f1ff05ee8/GEO_ExPro_v14i4.pdf|url-status=live}}</ref>

===Other===
In the United States and India, some coal-producing states have invested in Fischer–Tropsch plants. In Pennsylvania, Waste Management and Processors, Inc. was funded by the state to implement FT technology licensed from Shell and Sasol to convert so-called [[waste coal]] (leftovers from the mining process) into [[low-sulfur diesel]] fuel.<ref>{{cite web |archive-url=https://web.archive.org/web/20081211180710/http://www.state.pa.us/papower/cwp/view.asp?Q=446127&A=11 |archive-date=2008-12-11 |url=http://www.state.pa.us/papower/cwp/view.asp?Q=446127&A=11 |title=Governor Rendell leads with innovative solution to help address PA energy needs |publisher=State of Pennsylvania |url-status=dead}}</ref><ref>{{cite news |archive-url=https://web.archive.org/web/20090101164027/http://www.billingsgazette.com/newdex.php?display=rednews%2F2005%2F08%2F02%2Fbuild%2Fstate%2F25-coal-fuel.inc |title=Schweitzer wants to convert Otter Creek coal into liquid fuel |publisher=Billings Gazette |date=August 2, 2005 |archive-date=2009-01-01 |url=http://www.billingsgazette.com/newdex.php?display=rednews/2005/08/02/build/state/25-coal-fuel.inc |url-status=dead }}</ref>

==Research developments==
Choren Industries has built a plant in [[Germany]] that converts biomass to syngas and fuels using the Shell FT process structure. The company went bankrupt in 2011 due to impracticalities in the process.<ref>[https://web.archive.org/web/20020628070835/http://choren.com/] Choren official web site</ref><ref>{{Cite web |url=https://www.technologyreview.com/2005/11/23/230028/growing-biofuels-2/ |title=Fairley, Peter. Growing Biofuels – New production methods could transform the niche technology. ''MIT Technology Review'' November 23, 2005 |access-date=August 29, 2020 |archive-date=August 9, 2020 |archive-url=https://web.archive.org/web/20200809182936/https://www.technologyreview.com/2005/11/23/230028/growing-biofuels-2/ |url-status=live }}</ref>

[[Biomass gasification]] (BG) and Fischer–Tropsch (FT) synthesis can in principle be combined to produce renewable transportation fuels ([[biofuel]]s).<ref>{{Cite journal |last1=Inderwildi |first1=Oliver R. |last2=Jenkins |first2=Stephen J. |last3=King |first3=David A. |year=2008 |title=Mechanistic Studies of Hydrocarbon Combustion and Synthesis on Noble Metals |journal=Angewandte Chemie International Edition |volume=47 |issue=28 |pages=5253–5 |doi=10.1002/anie.200800685 |pmid=18528839|s2cid=34524430 }}</ref>

In partnership with Sunfire, [[Audi]] produces [[E-diesel]] in small scale with two steps, the second one being FT.<ref>{{Cite web |date=2017-11-08 |title=Audi steps up research into carbon-neutral synthetic fuels with new e-diesel pilot plant; power-to-liquids |url=https://www.greencarcongress.com/2017/11/audi-steps-up-research-into-carbon-neutral-synthetic-fuels-with-new-e-diesel-pilot-plant-power-to-li.html}}</ref>

===U.S. Air Force testing===
[[Syntroleum]], formerly a publicly traded United States company, has produced over {{convert|400,000|USgal|liter}} of diesel and jet fuel from the Fischer–Tropsch process using natural gas at its demonstration plant near [[Tulsa, Oklahoma]]. Using natural gas as a feedstock, the ultra-clean, low sulfur fuel has been tested extensively by the [[United States Department of Energy]] and the [[United States Department of Transportation]]. Syntroleum worked 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 United States military's largest user of fuel, began exploring alternative fuel sources in 1999. On December 15, 2006, a [[B-52]] took off from [[Edwards Air Force Base]], [[California]] for the first time powered solely by a 50–50 blend of [[JP-8]] 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 was part of the [[United States Department of Defense|Department of Defense]] Assured Fuel Initiative, an effort to develop secure domestic sources for the military energy needs. The Pentagon had hoped to reduce its use of crude oil from foreign producers and obtain about half of its aviation fuel from alternative sources by 2016.<ref name="anr1">{{Cite news |title=B-52 synthetic fuel testing: Center commander pilots first Air Force B-52 flight using solely synthetic fuel blend in all eight engines |last=Zamorano |first=Marti |date=2006-12-22 |work=Aerotech News and Review}}</ref> More recently in 2021, [https://www.biobased-diesel.com/post/twelve-emerging-fuels-technology-sign-master-license-agreement-to-scale-saf-production another batch of synthetic jet fuel was manufactured for the Air Force by Twelve and Emerging Fuels Technology] - the latter being Syntroleum's successor company which was established by the founders and management team of Syntroleum and having bought its laboratory in Tulsa.

===Carbon dioxide reuse===
Carbon dioxide is not a typical feedstock for FT catalysis. Hydrogen and carbon dioxide react over a cobalt-based catalyst, producing methane. With iron-based catalysts unsaturated short-chain hydrocarbons are also produced.<ref>{{cite journal|last=Dorner|first=Robert |author2=Dennis R. Hardy |author3=Frederick W. Williams |author4=Heather D. Willauer|title=Heterogeneous catalytic CO<sub>2</sub> conversion to value-added hydrocarbons|journal=Energy Environ. Sci.|year=2010|volume=3|issue=7 |pages=884–890|doi=10.1039/C001514H}}</ref> Upon introduction to the catalyst's support, [[ceria]] functions as a reverse water-gas shift catalyst, further increasing the yield of the reaction.<ref>{{cite web|last=Dorner|first=Robert|title=Catalytic Support for use in Carbon Dioxide Hydrogenation Reactions|url=https://patents.google.com/patent/US20110105630|access-date=2013-05-22|archive-date=2014-09-11|archive-url=https://web.archive.org/web/20140911134555/http://www.google.com/patents/US20110105630|url-status=live}}</ref> The short-chain hydrocarbons were upgraded to liquid fuels over solid acid catalysts, such as [[zeolite]]s.

== Process efficiency ==
Using conventional FT technology the process ranges in carbon efficiency from 25 to 50 percent<ref>{{Cite journal |last1=Unruh |first1=Dominik |last2=Pabst |first2=Kyra |last3=Schaub |first3=Georg |date=2010-04-15 |title=Fischer−Tropsch Synfuels from Biomass: Maximizing Carbon Efficiency and Hydrocarbon Yield  |journal=[[Energy & Fuels]] |volume=24 |issue=4 |pages=2634–2641 |doi=10.1021/ef9009185 |issn=0887-0624}}</ref> and a thermal efficiency of about 50%<ref name="ReferenceA">{{harvnb|de Klerk|2011}}</ref> for CTL facilities idealised at 60%<ref name="web.anl.gov">{{Cite web |url=http://web.anl.gov/PCS/acsfuel/preprint%20archive/Files/48_1_New%20Orleans__03-03_0567.pdf |title=Archived copy |access-date=2013-03-26 |archive-date=2017-04-28 |archive-url=https://web.archive.org/web/20170428140516/https://web.anl.gov/PCS/acsfuel/preprint%20archive/Files/48_1_New%20Orleans__03-03_0567.pdf |url-status=dead }}</ref> with GTL facilities at about 60%<ref name="ReferenceA" /> efficiency idealised to 80%<ref name="web.anl.gov"/> efficiency.

==Fischer–Tropsch in nature==
A Fischer–Tropsch-type process has also been suggested to have produced a few of the building blocks of [[DNA]] and [[RNA]] within [[asteroids]].<ref name="Pearce & Pudritz (2015)">{{Cite journal |last1=Pearce |first1=Ben K. D. |last2=Pudritz |first2=Ralph E. |date=2015 |title=Seeding the Pregenetic Earth: Meteoritic Abundances of Nucleobases and Potential Reaction Pathways |journal=[[The Astrophysical Journal]] |volume=807 |issue=1 |page=85 |arxiv=1505.01465 |bibcode=2015ApJ...807...85P |doi=10.1088/0004-637X/807/1/85|s2cid=93561811 }}</ref> Similarly, the hypothetical [[abiogenic petroleum]] formation requires some naturally occurring FT-like processes.

Biological Fischer-Tropsch-type chemistry can be carried out by the enzyme [[nitrogenase]] at ambient conditions.<ref>{{Cite journal |last1=Gerlach |first1=Deidra L. |last2=Lehnert |first2=Nicolai |date=2011-08-22 |title=Fischer–Tropsch Chemistry at Room Temperature? |url=https://onlinelibrary.wiley.com/doi/10.1002/anie.201102979 |journal=Angewandte Chemie International Edition |language=en |volume=50 |issue=35 |pages=7984–7986 |doi=10.1002/anie.201102979 |pmid=21761528 |issn=1433-7851|hdl=2027.42/87158 |hdl-access=free }}</ref><ref>{{Cite journal |last1=Lee |first1=Chi Chung |last2=Hu |first2=Yilin |last3=Ribbe |first3=Markus W. |date=2010-08-06 |title=Vanadium Nitrogenase Reduces CO |journal=Science |language=en |volume=329 |issue=5992 |pages=642 |doi=10.1126/science.1191455 |issn=0036-8075 |pmc=3141295 |pmid=20689010|bibcode=2010Sci...329..642L }}</ref>

== See also ==
{{Portal|Energy|Renewable energy|Chemistry}}
{{Div col}}
* {{annotated link|Bergius process}}
* {{annotated link|Coal gasification}}
* {{annotated link|Fischer assay}}
* {{annotated link|Hydrogenation}}, a generic term for this type of process
* {{annotated link|Hubbert peak theory}}
* {{annotated link|Industrial gas}}
* {{annotated link|Karrick process}}
* {{annotated link|Sabatier reaction}}
* {{annotated link|Steam methane reforming}}
* {{annotated link|Synthetic Liquid Fuels Program}}

{{Div col end}}

==References==
{{Reflist|30em}}

==Further reading==
* {{cite book | title=Fischer–Tropsch refining | edition = 1st | publisher=Wiley-VCH | last=de Klerk|first=Arno | date=2011 | location=Weinheim, Germany | isbn = 9783527326051}}
* {{cite book | title=Catalysis in the refining of Fischer–Tropsch syncrude | publisher=[[Royal Society of Chemistry]] | last1=de Klerk|first1=Arno |first2=Edward |last2=Furimsky | s2cid=101325929 | date=15 Dec 2010 | location=Cambridge|doi=10.1039/9781849732017| isbn=978-1-84973-080-8 }}
* {{cite book |title=Bibliography of the Fischer-Tropsch Synthesis and Related Processes |volume=1 |last1=Anderson |first1=H. C. |last2=Wiley |first2=J. L. |last3=Newell |first3=A. |year=1954 |url=https://books.google.com/books?id=bJAzAAAAIAAJ}}
* {{cite book |title=Bibliography of the Fischer-Tropsch Synthesis and Related Processes |volume=2 |last1=Anderson |first1=H. C. |last2=Wiley |first2=J. L. |last3=Newell |first3=A. |year=1955|url=https://books.google.com/books?id=sJIzAAAAIAAJ}}

==External links==

* Modeling and Integration of Green-Hydrogen-Assisted Carbon Dioxide Utilization for Hydrocarbon Manufacturing [https://pubs.acs.org/doi/10.1021/acs.iecr.4c02255]

* [http://www.fischer-tropsch.org/ Fischer–Tropsch archives]
* [http://web.mit.edu/mitei/docs/reports/kreutz-fischer-tropsch.pdf Fischer–Tropsch fuels from coal and biomass]
* [http://www.aapg.org/explorer/2002/11nov/abiogenic.cfm Abiogenic gas debate (AAPG Explorer Nov. 2002)]
* [https://explorer.aapg.org/story/articleid/46994/gas-origin-theories-to-be-studied Gas origin theories to be studied (AAPG Explorer Nov. 2002)]
* [https://web.archive.org/web/20100125153517/http://www.spe.org/elibinfo/eLibrary_Papers/spe/1982/82UGR/00010836/00010836.htm Unconventional ideas about unconventional gas (Society of Petroleum Engineers)]
* ''[https://web.archive.org/web/20051106005801/http://www.fischer-tropsch.org/primary_documents/patents/GB/gb309002.pdf Process of synthesis of liquid hydrocarbons]'' – Great Britain patent GB309002 – [[Hermann Plauson]]
* ''[http://www.technologyreview.com/read_article.aspx?id=16713&ch=biztech Clean diesel from coal]'' by Kevin Bullis
* ''[https://web.archive.org/web/20071128055653/http://tbp.org/pages/Publications/Bent/Features/Su07Uhrig.pdf Implementing the "Hydrogen Economy" with Synfuels (pdf)]''
* [http://www.carbontoliquids.com/ Carbon-to-liquids research]
* [https://doi.org/10.1007%2Fs10562-010-0366-4 Effect of alkali metals on cobalt catalysts]

{{Bioenergy}}

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{{DEFAULTSORT:Fischer-Tropsch Process}}
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