Fischer–Tropsch process
The Fischer–Tropsch process (FT) is a collection of chemical reactions that converts a mixture of carbon monoxide and hydrogen, known as syngas, into liquid hydrocarbons.
[1] In the usual implementation, carbon monoxide and hydrogen, the feedstocks for FT, are produced from coal, natural gas, or biomass in a process known as gasification.
[2] 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.
[3][4][5] The process was first developed by Franz Fischer and Hans Tropsch at the Kaiser Wilhelm Institute for Coal Research in Mülheim an der Ruhr, Germany, in 1925.
In addition to alkane formation, competing reactions give small amounts of alkenes, as well as alcohols and other oxygenated hydrocarbons.
[10] Other potential intermediates are various C1 fragments including formyl (CHO), hydroxycarbene (HCOH), hydroxymethyl (CH2OH), methyl (CH3), methylene (CH2), methylidyne (CH), and hydroxymethylidyne (COH).
Coal-based FT plants produce varying amounts of CO2, depending upon the energy source of the gasification process.
In gas to liquids (GTL) technology, the hydrocarbons are low molecular weight materials that often would be discarded or flared.
Four types of reactors are discussed: In general the product distribution of hydrocarbons formed during the Fischer–Tropsch process follows an Anderson–Schulz–Flory distribution,[14] which can be expressed as: where Wn 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.
[11] 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.
Being petroleum-poor but coal-rich, Germany used the process during World War II to produce ersatz (replacement) fuels.
[citation needed] Around the 1930s and 1940s, Arthur Imhausen developed and implemented an industrial process for producing edible fats from these synthetic oils through oxidation.
[26] "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.
[29] 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.
[31] Sasol uses coal and natural gas as feedstocks and produces a variety of synthetic petroleum products, including most of the country's diesel fuel.
[32] 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.
Construction is underway for Velocys' commercial reference plant incorporating its microchannel Fischer–Tropsch technology; ENVIA Energy's Oklahoma City GTL project being built adjacent to Waste Management's East Oak landfill site.
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.
[36] This unit also serves as an operations training environment for the 1100 BPD Juniper GTL facility constructed in Westlake LA.
Commercial-scale facilities were planned for Rialto, California; Natchez, Mississippi; Port St. Joe, Florida; and White River, Ontario.
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.
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 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.
[44][45] Choren Industries has built a plant in Germany that converts biomass to syngas and fuels using the Shell FT process structure.
[46][47] Biomass gasification (BG) and Fischer–Tropsch (FT) synthesis can in principle be combined to produce renewable transportation fuels (biofuels).
Syntroleum has worked to develop a synthetic jet fuel blend that will help the Air Force to reduce its dependence on imported petroleum.
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.
This program is part of the Department of Defense 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.
