Synthetic fuel

Synthetic fuel

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Synthetic fuel or synfuel is a liquid fuel obtained 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...

, oil shale
Oil shale
Oil shale, an organic-rich fine-grained sedimentary rock, contains significant amounts of kerogen from which liquid hydrocarbons called shale oil can be produced...

, 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....

. It may also refer to fuels derived from other solids such as plastic
Plastic
A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...

s or rubber waste. It may also (less often) refer to gaseous fuels produced in a similar way. Common use of the term "synthetic fuel" is to describe fuels manufactured via Fischer Tropsch conversion, methanol to gasoline conversion
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...

, or direct coal liquefaction
Coal liquefaction
-Methods:The liquefaction processes are classified as direct conversion to liquids processes and indirect conversion to liquids processeses. Direct processes are carbonization and hydrogenation.-Pyrolysis and carbonization processes:...

.

July 2009 worldwide commercial synthetic fuels production capacity is over 240000 oilbbl/d, with numerous new projects in construction or development.

Classification and principles


The term 'synthetic fuel' has several different meanings and it may include different types of fuels. More traditional definitions, e.g. definition given by the International Energy Agency
International Energy Agency
The International Energy Agency is a Paris-based autonomous intergovernmental organization established in the framework of the Organisation for Economic Co-operation and Development in 1974 in the wake of the 1973 oil crisis...

, define 'synthetic fuel' as any liquid fuel obtained from coal or natural gas. The Energy Information Administration
Energy Information Administration
The U.S. Energy Information Administration is the statistical and analytical agency within the U.S. Department of Energy. EIA collects, analyzes, and disseminates independent and impartial energy information to promote sound policymaking, efficient markets, and public understanding of energy and...

 defines synthetic fuels in its Annual Energy Outlook 2006, as fuels produced from coal, natural gas, 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....

 feedstocks through chemical conversion into synthetic crude
Synthetic crude
Synthetic crude is the output from a bitumen/extra heavy oil upgrader facility used in connection with oil sand production. It may also refer to shale oil, an output from an oil shale pyrolysis. The properties of the synthetic crude depend on the processes used in the upgrading. Typically, it is...

 and/or synthetic liquid products. A number of synthetic fuel's definitions include also fuels produced from biomass, and industrial and municipal waste. The definition of synthetic fuel may also consist of oil sands and oil shale
Oil shale
Oil shale, an organic-rich fine-grained sedimentary rock, contains significant amounts of kerogen from which liquid hydrocarbons called shale oil can be produced...

 as synthetic fuel's sources and in addition to liquid fuels also gaseous fuels are covered. On his 'Synthetic fuels handbook' a petrochemist James G. Speight included liquid and gaseous fuels as well as clean solid fuels produced by conversion of coal, oil shale or tar sands, and various forms of biomass, although he admits that in the context of substitutes for petroleum-based fuels it has even wider meaning. Depending the context, also methanol
Methanol
Methanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...

, ethanol
Ethanol
Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...

 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...

 may be included.

Synthetic fuels are produced by the chemical process of conversion
Chemical reaction
A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity...

. Conversion methods could be direct conversion into liquid transportation fuels, or indirect conversion, in which the source substance is converted initially into syngas
Syngas
Syngas is the name given to a gas mixture that contains varying amounts of carbon monoxide and hydrogen. Examples of production methods include steam reforming of natural gas or liquid hydrocarbons to produce hydrogen, the gasification of coal, biomass, and in some types of waste-to-energy...

 which then goes through additional conversion process to become liquid fuels. Basic conversion methods include carbonization
Carbonization
Carbonization or carbonisation is the term for the conversion of an organic substance into carbon or a carbon-containing residue through pyrolysis or destructive distillation. It is often used in organic chemistry with reference to the generation of coal gas and coal tar from raw coal...

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

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

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

.

History



Direct conversion of coal to synthetic fuel was originally developed in Germany.
The 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...

 was developed by Friedrich Bergius
Friedrich Bergius
Friedrich Karl Rudolf Bergius was a German chemist known for the Bergius process for producing synthetic fuel from coal, Nobel Prize in Chemistry in recognition of contributions to the invention and development of chemical high-pressure methods...

, yielding a patent on the 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...

 in 1913. Karl Goldschmidt invited him to build an industrial plant at his factory the Th. Goldschmidt AG (now known as Evonik Industries
Evonik Industries
Evonik Industries is an industrial corporation in Germany owned by RAG Foundation and one of the world´s leading specialty chemicals companies. It was created on 12 September 2007 as a result of restructuring of the mining and technology group RAG...

) in 1914. The production began only in 1919.

Also indirect coal conversion (where coal is gasified and then converted to synthetic fuels) was developed in Germany 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 :...

 in 1923. 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...

, Germany used synthetic oil manufacturing to produce substitute (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...

) oil products by using the 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...

 (from coal), the Fischer–Tropsch process (water gas
Water gas
Water gas is a synthesis gas, containing carbon monoxide and hydrogen. It is a useful product but requires careful handling because of the risk of carbon monoxide poisoning. The gas is made by passing steam over a red-hot hydrocarbon fuel such as coke:...

), and other methods (Zeitz
Zeitz
Zeitz is a town in the Burgenlandkreis district, in Saxony-Anhalt, Germany. It is situated on the river Weiße Elster, in the middle of the triangle of the federal states Saxony-Anhalt, Thuringia and Saxony.-History:...

 used the TTH and MTH processes).
Before World War Two in 1931, the British Department of Scientific and Industrial Research located in Greenwich, England set up a small facility where hydrogen gas at extreme high pressure was combined with coal to make a synthetic fuel.

The Bergius process plants were the primary source of Nazi Germany's high-grade aviation gasoline and the source of most of its synthetic oil, 99% of its synthetic rubber
Synthetic rubber
Synthetic rubber is is any type of artificial elastomer, invariably a polymer. An elastomer is a material with the mechanical property that it can undergo much more elastic deformation under stress than most materials and still return to its previous size without permanent deformation...

 and nearly all of its synthetic methanol
Methanol
Methanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...

, synthetic ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...

, and nitric acid
Nitric acid
Nitric acid , also known as aqua fortis and spirit of nitre, is a highly corrosive and toxic strong acid.Colorless when pure, older samples tend to acquire a yellow cast due to the accumulation of oxides of nitrogen. If the solution contains more than 86% nitric acid, it is referred to as fuming...

. Nearly 1/3 of the Bergius production was produced by plants in Pölitz  and Leuna
Leuna
Leuna is a town in the Saalekreis, Saxony-Anhalt, eastern Germany, south of Merseburg and Halle. It is known for the Leunawerke , at 13 km2 one of the biggest chemical industrial complexes in Germany, where a very wide range of chemicals and plastics is produced...

, with more than 1/3 more in five other plants (Ludwigshafen had a much smaller Bergius plant which improved "gasoline quality by dehydrogenation" using the DHD process).

Synthetic fuel grades included "T.L. [jet] fuel ", "first quality aviation gasoline", "aviation base gasoline", and "gasoline - middle oil"; and "producer gas" and diesel were synthesized for fuel as well (e.g., converted armored tanks used producer gas). By early 1944, German synthetic fuel production had reached more than 124000 oilbbl/d from 25 plants, including 10 in the Ruhr Area
Ruhr Area
The Ruhr, by German-speaking geographers and historians more accurately called Ruhr district or Ruhr region , is an urban area in North Rhine-Westphalia, Germany. With 4435 km² and a population of some 5.2 million , it is the largest urban agglomeration in Germany...

. In 1937, the four central Germany lignite
Lignite
Lignite, often referred to as brown coal, or Rosebud coal by Northern Pacific Railroad,is a soft brown fuel with characteristics that put it somewhere between coal and peat...

 coal plants at Böhlen
Böhlen
Böhlen is a town in the Free State of Saxony, Germany, south of Leipzig. Its main features are a small airport and a power-plant. It is located in the newly built Neuseenland, the lakes created in the former open-pit mining areas.- References :...

, Leuna, Magdeburg
Magdeburg
Magdeburg , is the largest city and the capital city of the Bundesland of Saxony-Anhalt, Germany. Magdeburg is situated on the Elbe River and was one of the most important medieval cities of Europe....

/Rothensee, and Zeitz, along with the Ruhr Area
Ruhr Area
The Ruhr, by German-speaking geographers and historians more accurately called Ruhr district or Ruhr region , is an urban area in North Rhine-Westphalia, Germany. With 4435 km² and a population of some 5.2 million , it is the largest urban agglomeration in Germany...

 bituminous coal
Bituminous coal
Bituminous coal or black coal is a relatively soft coal containing a tarlike substance called bitumen. It is of higher quality than lignite coal but of poorer quality than Anthracite...

 plant at Scholven/Buer
Buer, Germany
Buer is the largest suburb of Gelsenkirchen. The Hochstrasse in the heart of Buer is the largest shopping street in Gelsenkirchen.-History:...

, had produced 4.8 Moilbbl of fuel. Four new hydrogenation plants were subsequently erected at Bottrop
Bottrop
Bottrop is a city in west central Germany, on the Rhine-Herne Canal, in North Rhine-Westphalia. Located in the Ruhr industrial area, Bottrop adjoins Essen, Oberhausen, Gladbeck and Dorsten. The city had been a coal-mining and rail center and contains factories producing coal-tar derivatives,...

-Welheim (which used "Bituminous coal tar
Coal tar
Coal tar is a brown or black liquid of extremely high viscosity, which smells of naphthalene and aromatic hydrocarbons. Coal tar is among the by-products when coal iscarbonized to make coke or gasified to make coal gas...

 pitch"), Gelsenkirchen
Gelsenkirchen
Gelsenkirchen is a city in North Rhine-Westphalia, Germany. It is located in the northern part of the Ruhr area. Its population in 2006 was c. 267,000....

 (Nordstern), Pölitz, and, at 200,000 tons/yr Wesseling
Wesseling
Wesseling is an industrial German city on the Rhine bordering Cologne city on the south. Wesseling originates from the Latin „Wasliacum“ which means "Villlage of Waslica" The story that Wesselig originates from "changing of the rope"...

. Nordstern and Pölitz/Stettin
Szczecin
Szczecin , is the capital city of the West Pomeranian Voivodeship in Poland. It is the country's seventh-largest city and the largest seaport in Poland on the Baltic Sea. As of June 2009 the population was 406,427....

 used bituminous coal, as did the new Blechhammer
Blechhammer
The Blechhammer area was the location of Nazi Germany chemical plants, prisoner of war camps, and forced labor camps . Labor camp prisoners began arriving as early as June 17, 1942, and in July 1944, 400-500 men were transferred from the Terezin family camp to Blechhammer...

 plants. Heydebreck
Heydebreck-Cosel
Heydebreck was a Nazi Germany village area with POW camps Arbeitskommando E711A and Bau und Arbeits camp 20 . Five km west in the Cosel district was a subcamp of Auschwitz III operated from April 1, 1944 to January 26, 1945...

 synthesized food oil, which was tested on concentration camp prisoners. The Geilenberg Special Staff was using 350,000 mostly foreign forced laborers
Forced labor in Germany during World War II
The use of forced labour in Nazi Germany and throughout German-occupied Europe during World War II took place on an unprecedented scale. It was a vital part of the German economic exploitation of conquered territories. It also contributed to the mass extermination of populations in German-occupied...

 to reconstruct the bombed synthetic oil plants, and, in an emergency decentralization program, to build 7 underground hydrogenation plants for bombing protection (none were completed). (Planners had rejected an earlier such proposal because the war was to be won before the bunkers would be completed.) In July 1944, the 'Cuckoo' project underground synthetic oil plant (800,000 m2) was being "carved out of the Himmelsburg
Thuringian Forest
The Thuringian Forest running northwest to southeast, forms a continuous stretch of ancient rounded mountains posing ample difficulties in transit routing save through a few navigable passes in the southern reaches of the German state of Thuringia. It is about long and wide...

" North of the Mittelwerk
Mittelwerk
Central Works was a World War II factory that used Mittelbau-Dora forced labor in 2 main tunnels in the Kohnstein. The underground facility produced V-2 rockets, V-1 flying bombs, and other Nazi weapons.-Mittelwerk GmbH:...

, but the plant was unfinished at the end of WWII.

Indirect Fischer-Tropsch ("FT") technologies were brought to the US after World War 2, and a 7000 oilbbl/d plant was designed by HRI, and built in Brownsville Texas. The plant represented the first commercial use of high-temperature Fischer Tropsch conversion. It operated from 1950 to 1955, when it was shut down when the price of oil dropped due to enhanced production and huge discoveries in the Middle East.

After World War Two, in 1949 a demonstration plant for converting coal to gasoline was built and operated by the U.S. Bureau of Mines in Louisiana, Missouri. Direct coal conversion plants were also developed in the US after WW2, including a 3 TPD plant in Lawrenceville, NJ, and a 250-600 TPD Plant in Catlettsburg, KY.

Processes


There are numerous processes that can be used to produce synthetic fuels.

These broadly fall into three categories: Indirect, Direct, and Biofuel processes.


Indirect conversion


Indirect conversion has the widest deployment worldwide, with global production totaling around 260000 oilbbl/d, and many additional projects under active development.

Indirect conversion broadly refers to a process in which biomass, coal, or natural gas is converted to a mix of hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

 and 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...

 known as syngas either through gasification
Gasification
Gasification is a process that converts organic or fossil based carbonaceous materials into carbon monoxide, hydrogen, carbon dioxide and methane. This is achieved by reacting the material at high temperatures , without combustion, with a controlled amount of oxygen and/or steam...

 or steam methane reforming, and that syngas is processed into a liquid transportation fuel using one of a number of different conversion techniques depending on the desired end product.



The primary technologies that produce synthetic fuel from syngas are Fischer-Tropsch synthesis and the Mobil process (also known as Methanol To Gasoline, or MTG). There are some technologies under development to produce ethanol from syngas, though these have not yet been demonstrated at commercial scale.

The Fischer-Tropsch process reacts syngas with typically a cobalt or iron-based catalyst, and transforms the gas into liquid products (primarily diesel fuel and jet fuel) and potentially waxes (depending on the FT process employed).

The process of producing synfuels through indirect conversion is often referred to as coal-to-liquids (CTL), 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...

 (GTL) or biomass-to-liquids
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....

 (BTL), depending on the initial feedstock. At least three projects (Ohio River Clean Fuels, Illinois Clean Fuels, and Rentech Natchez) are combining coal and biomass feedstocks, creating hybrid-feedstock synthetic fuels known as Coal and Biomass To Liquids (CBTL).

Indirect conversion process technologies can also be used to produce hydrogen, potentially for use in fuel cell vehicles, either as slipstream co-product, or as a primary output.

Direct conversion


Direct conversion refers to processes in which coal or biomass feedstocks are converted directly into intermediate or final products, without going through the intermediate step of conversion to syngas via gasification
Gasification
Gasification is a process that converts organic or fossil based carbonaceous materials into carbon monoxide, hydrogen, carbon dioxide and methane. This is achieved by reacting the material at high temperatures , without combustion, with a controlled amount of oxygen and/or steam...

.

Direct conversion processes can be broadly broken up into two different methods: Pyrolysis and carbonization, and hydrogenation.

Hydrogenation processes


One of the main methods of direct conversion of coal to liquids by hydrogenation process is the Bergius process. In this process, coal is liquefied by mixing it with hydrogen gas and heating the system (hydrogenation). Dry coal is mixed with heavy oil recycled from the process. Catalyst is typically added to the mixture. The reaction occurs at between 400 °C (752 °F) to 5000 °C (9,032 °F) and 20 to 70 MPa
Pascal (unit)
The pascal is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre...

 hydrogen pressure. The reaction can be summarized as follows:



After World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

 several plants were built in Germany; these plants were extensively used 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 supply Germany with fuel and lubricants.

The Kohleoel Process, developed in Germany by Ruhrkohle
RAG Aktiengesellschaft
RAG AG, formerly Ruhrkohle AG, is the largest German coal mining corporation. The company headquarters are in Herne in the Ruhr area. The company was founded on 27 November 1968, consolidating several coalmining corporations into the Ruhrkohle AG....

 and VEBA
VEBA
VEBA AG was a German energy company. VEBA was founded in 1929 as a holding company owned by the state of Prussia, and was privatized in 1965. VEBA became a part of E.ON in 2000....

, was used in the demonstration plant with the capacity of 200 ton of lignite
Lignite
Lignite, often referred to as brown coal, or Rosebud coal by Northern Pacific Railroad,is a soft brown fuel with characteristics that put it somewhere between coal and peat...

 per day, built in Bottrop
Bottrop
Bottrop is a city in west central Germany, on the Rhine-Herne Canal, in North Rhine-Westphalia. Located in the Ruhr industrial area, Bottrop adjoins Essen, Oberhausen, Gladbeck and Dorsten. The city had been a coal-mining and rail center and contains factories producing coal-tar derivatives,...

, Germany. This plant operated from 1981 to 1987. In this process, coal is mixed with a recycle solvent and iron catalyst. After preheating and pressurizing, H2 is added. The process takes place in tubular reactor at the pressure of 300 bar and at the temperature of 470 °C (878 °F). This process was also explored 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.

In 1970-1980s, Japanese companies Nippon Kokan, Sumitomo Metal Industries
Sumitomo Metal Industries
is a company with seat in Osaka, Japan. )It is the third largest integrated steel manufacturer in Japan withthree integrated steelworks and several other manufacturing plants.It is one of the largest manufacturers of Seamless Pipes and Tubes,...

 and Mitsubishi Heavy Industries
Mitsubishi Heavy Industries
, or MHI, is a Japanese company. It is one of the core companies of Mitsubishi Group.-History:In 1870 Yataro Iwasaki, the founder of Mitsubishi took a lease of Government-owned Nagasaki Shipyard. He named it Nagasaki Shipyard & Machinery Works, and started the shipbuilding business on a full scale...

 developed the NEDOL process. In this process, coal is mixed with a recycled solvent and a synthetic iron-based catalyst; after preheating H2 is added. The reaction takes place in tubular reactor at temperature between 430 °C (806 °F) and 465 °C (869 °F) at the pressure 150-200 bar. The produced oil has low quality and requires intensive upgrading. H-Coal process, developed by Hydrocarbon Research, Inc., in 1963, mixes pulverized coal with recycled liquids, hydrogen and catalyst in the ebullated bed reactor. Advantages of this process are that dissolution and oil upgrading are taking place in the single reactor, products have high H/C ration, and a fast ration time, while the main disadvantages are high gas yield, high hydrogen consumption, and limitation of oil usage only as a boiler oil because of impurities.

The SRC-I and SRC-II (Solvent Refined Coal) processes developed by Gulf Oil
Gulf Oil
Gulf Oil was a major global oil company from the 1900s to the 1980s. The eighth-largest American manufacturing company in 1941 and the ninth-largest in 1979, Gulf Oil was one of the so-called Seven Sisters oil companies...

 and implemented as pilot plants in the United States in the 1960s and 1970s. The Nuclear Utility Services Corporation developed hydrogenation process which was patented by Wilburn C. Schroeder in 1976. The process involved dried, pulverized coal mixed with roughly 1wt% molybdenum
Molybdenum
Molybdenum , is a Group 6 chemical element with the symbol Mo and atomic number 42. The name is from Neo-Latin Molybdaenum, from Ancient Greek , meaning lead, itself proposed as a loanword from Anatolian Luvian and Lydian languages, since its ores were confused with lead ores...

 catalysts. Hydrogenation occurred by use of high temperature and pressure syngas produced in a separate gasifier. The process ultimately yielded a synthetic crude product, Naphtha
Naphtha
Naphtha normally refers to a number of different flammable liquid mixtures of hydrocarbons, i.e., a component of natural gas condensate or a distillation product from petroleum, coal tar or peat boiling in a certain range and containing certain hydrocarbons. It is a broad term covering among the...

, a limited amount of C3/C4 gas, light-medium weight liquids (C5-C10) suitable for use as fuels, small amounts of NH3 and significant amounts of CO2. Other single-stage hydrogenation processes are the Exxon Donor Solvent Process, the Imhausen High-pressure Process, and the Conoco Zinc Chloride Process.

There is also a number of two-stage direct liquefaction processes; however, after 1980s only the Catalytic Two-stage Liquefaction Process, modified from the H-Coal Process; the Liquid Solvent Extraction Process by British Coal
British Coal
thumb|right|British Coal company logoThe British Coal Corporation was a nationalised corporation in the United Kingdom responsible for the extraction of coal...

; and the Brown Coal Liquefaction Process of Japan have been developed.

Chevron Corporation developed a process invented by Joel W. Rosenthal called the Chevron Coal Liquefaction Process (CCLP). It is unique due the close-coupling of the non-catalytic dissolver and the catalytic hydroprocessing unit. The oil produced had properties that were unique when compared to other coal oils; it was lighter and had far fewer heteroatom impurities. The process was scaled-up to the 6 ton per day level, but not proven commercially.

Pyrolysis and carbonization processes



There are a number of different carbonization processes. The carbonization conversion occurs through pyrolysis
Pyrolysis
Pyrolysis is a thermochemical decomposition of organic material at elevated temperatures without the participation of oxygen. It involves the simultaneous change of chemical composition and physical phase, and is irreversible...

 or destructive distillation
Destructive distillation
Destructive distillation is the chemical process involving the decomposition of feedstock by heating to a high temperature; the term generally applies to processing of organic material in the absence of air or in the presence of limited amounts of oxygen or other reagents, catalysts, or solvents,...

, and it produces condensable coal tar
Coal tar
Coal tar is a brown or black liquid of extremely high viscosity, which smells of naphthalene and aromatic hydrocarbons. Coal tar is among the by-products when coal iscarbonized to make coke or gasified to make coal gas...

, oil and water vapor, non-condesable synthetic gas, and a solid residue-char
Char
Char is the solid material that remains after light gases and tar coal tar have been driven out or released from a carbonaceous material during the initial stage of combustion, which is known as carbonization, charring, devolatilization or pyrolysis.Further stages of efficient combustion are...

. The condensed coal tar and oil are then further processed by hydrogenation to remove sulfur
Sulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...

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

 species, after which they are processed into fuels.

The typical example of carbonization is the 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...

. The process was invented by Lewis Cass Karrick
Lewis Karrick
Lewis Cass Karrick was an American petroleum refinery engineer, oil shale and coal technologist, and inventor. He patented several coal and oil shale related inventions, and he also refined and perfected a low-temperature carbonization and pyrolysis process for processing coal and other...

 in the 1920s. The Karrick process is a low-temperature carbonization
Carbonization
Carbonization or carbonisation is the term for the conversion of an organic substance into carbon or a carbon-containing residue through pyrolysis or destructive distillation. It is often used in organic chemistry with reference to the generation of coal gas and coal tar from raw coal...

 process, where coal is heated at 680 °F (360 °C) to 1380 °F (748.9 °C) in the absence of air. These temperatures optimize the production of coal tars richer in lighter hydrocarbons than normal coal tar. However, the produced liquids are mostly a by-product and the main product is semi-coke, a solid and smokeless fuel.

The COED Process, developed by FMC Corporation, uses a fluidized bed
Fluidized bed
A fluidized bed is formed when a quantity of a solid particulate substance is placed under appropriate conditions to cause the solid/fluid mixture to behave as a fluid. This is usually achieved by the introduction of pressurized fluid through the particulate medium...

 for processing, in combination with increasing temperature, through four stages of pyrolysis. Heat is transferred by hot gases produced by combustion of part of the produced char. A modification of this process, the COGAS Process, involves the addition of gasification of char. The TOSCOAL Process, an analogue to the TOSCO II oil shale retorting process
TOSCO II process
The TOSCO II process is an above ground retorting technology for shale oil extraction, which uses fine particles of oil shale that are heated in a rotating kiln. The particularity of this process is that it use hot ceramic balls for the heat transfer between the retort and a heater...

 and Lurgi-Ruhrgas process
Lurgi-Ruhrgas process
The Lurgi–Ruhrgas process is an above-ground coal liquefaction and shale oil extraction technology. It is classified as a hot recycled solids technology.-History:...

, which is also used for the shale oil extraction, uses hot recycled solids for the heat transfer.

Liquid yields of pyrolysis and Karrick processes are generally low for practical use for synthetic liquid fuel production. Furthermore, the resulting liquids are of low quality and require further treatment before they can be used as motor fuels. In summary, there is little possibility that this process will yield economically viable volumes of liquid fuel.

Biofuels processes


One example of a Biofuel based synthetic fuel process is Hydrotreated Renewable Jet (HRJ) fuel.
There are a number of variants of these processes under development, and the testing and certification process for HRJ aviation fuels is beginning.

There are two such process under development by UOP
UOP LLC
UOP LLC, formerly known as Universal Oil Products, is a multi-national company developing and delivering technology to the petroleum refining, gas processing, petrochemical production, and major manufacturing industries....

. One using solid biomass feedstocks, and one using bio-oil and fats. The process using solid second-generation biomass sources such as switchgrass or woody 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....

 uses pyrolysis to produce a bio-oil, which is then catalytically stabilized and deoxygenated to produce a jet-range fuel. The process using natural oils and fats goes through a deoxygenation process, followed by hydrocracking and isomerization to produce a renewable Synthetic Paraffinic Kerosene jet fuel.

Oil sand and oil shale processes



Synthetic crude
Synthetic crude
Synthetic crude is the output from a bitumen/extra heavy oil upgrader facility used in connection with oil sand production. It may also refer to shale oil, an output from an oil shale pyrolysis. The properties of the synthetic crude depend on the processes used in the upgrading. Typically, it is...

 may also be created by upgrading
Upgrader
An upgrader is a facility that upgrades bitumen into synthetic crude oil. Upgrader plants are typically located close to oil sands production, for example, the Athabasca oil sands in Alberta, Canada or the Orinoco tar sands in Venezuela....

 bitumen (a tar like substance found in oil sands), or synthesizing 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 from oil shale. There are number of processes extracting shale oil (synthetic crude oil) from oil shale
Oil shale
Oil shale, an organic-rich fine-grained sedimentary rock, contains significant amounts of kerogen from which liquid hydrocarbons called shale oil can be produced...

 by pyrolysis, hydrogenation, or thermal dissolution.

Commercialization



The leading company in the commercialization of synthetic fuel is 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...

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

.

Worldwide commercial synthetic fuels plant capacity is over 240000 oilbbl/d, including indirect conversion Fischer Tropsch plants in South Africa (Mossgas, Secunda CTL), Qatar {Oryx GTL
Oryx GTL
ORYX GTL is a synthetic fuel plant based in Ras Laffan Industrial City, Qatar, that is owned by Qatar Petroleum and Sasol . It uses gas to liquids technology for converting natural gas into liquid petroleum products. The capacity of Oryx GTL is of oil. When commissioned, it was the world's first...

}, and Malaysia (Shell Bintulu), and a Mobil process (Methanol to Gasoline) plant in New Zealand.

Numerous large projects are under construction in China and Qatar. Some analysts believe that Chinese CTL production will exceed that of South Africa by 2015, and new and existing GTL capacity in Qatar should also exceed the July 2009 South African production level some time in 2011.

Existing producers


The leading company in the commercialization of synthetic fuel is 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...

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

. Sasol operates the world's only commercial Fischer Tropsch coal-to-liquids facility at Secunda, with a capacity of 150000 oilbbl/d.

Sasol's Oryx Fischer Tropsch gas-to-liquids plant in Ras Laffan Industrial City
Ras Laffan Industrial City
Ras Laffan Industrial City is an industrial hub located north of Doha, Qatar. It is administrated by Qatar Petroleum.Ras Laffan Industrial City is the Qatar's main site for production of liquefied natural gas and gas-to-liquid...

, Qatar is running at 29000 oilbbl/d capacity, near its anticipated 34000 oilbbl/d nameplate capacity.

Royal Dutch Shell
Royal Dutch Shell
Royal Dutch Shell plc , commonly known as Shell, is a global oil and gas company headquartered in The Hague, Netherlands and with its registered office in London, United Kingdom. It is the fifth-largest company in the world according to a composite measure by Forbes magazine and one of the six...

 operates a 14700 oilbbl/d Fischer Tropsch gas-to-liquids plant in Bintulu, Malaysia.

The Mossgas gas to liquids plant in South Africa produces 45000 oilbbl/d of Fischer Tropsch synthetic fuels.

Other companies that have developed coal- or gas-to-liquids processes (at the pilot plant or commercial stage) include ExxonMobil
ExxonMobil
Exxon Mobil Corporation or ExxonMobil, is an American multinational oil and gas corporation. It is a direct descendant of John D. Rockefeller's Standard Oil company, and was formed on November 30, 1999, by the merger of Exxon and Mobil. Its headquarters are in Irving, Texas...

, StatoilHydro
StatoilHydro
Statoil ASA, trading as Statoil and formerly known as StatoilHydro, is a Norwegian energy company, formed by the 2007 merger of Statoil with the oil and gas division of Norsk Hydro. The Government of Norway is the largest shareholder in Statoil with 67% of the shares...

, Rentech
Rentech
Rentech is a United States company engaged in development and commercialization of a patented and proprietary Fischer-Tropsch process for the conversion of various feedstocks to liquids fuels and chemicals...

, and 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...

 .

Projects under construction


The Pearl GTL project
Pearl GTL
Pearl GTL is a gas to liquids project based in Ras Laffan, Qatar. It will convert natural gas into liquid petroleum products. When constructed, it will be the largest GTL plant in the world.-Technical features:...

, a joint venture of Shell and Qatar Petroleum
Qatar Petroleum
Qatar Petroleum is a state owned petroleum company in Qatar. The company operates all oil and gas activities in Qatar, including exploration, production, refining, transport, and storage. QP's Chairman Abdullah Bin Hamad Al-Attiyah, is also the head of the Ministry of Energy and Industry and, as...

, is under construction in Ras Laffan, Qatar, and will produce 140000 oilbbl/d of Fischer Tropsch petroleum liquids starting in 2011 (first train) and 2012 (second train).

The Escravos GTL
Escravos GTL
Escravos GTL is a gas to liquids project based in Escravos region, Nigeria. It is located in the Niger Delta about southeast of Lagos. The plant will convert natural gas into liquid petroleum products.-History:...

 project in Nigeria is expected to produce 34000 oilbbl/d of Fischer Tropsch synthetic fuel in 2011.

Shenhua completed a trial run in January 2009, and expects to begin operation in July 2009 of their 1.08 million ton per year (roughly 22200 oilbbl/d) direct coal liquefaction plant (Erdos CTL
Erdos CTL
Erdos CTL is a coal liquefaction plant at Ejin Horo Banner in Inner Mongolia, China. It is the biggest coal-to-liquids complex outside South Africa with a capacity of . The project is developed by Shenhua Coal Liquefaction, a subsidiary of Shenhua Group...

) in Ejin Horo Banner
Ejin Horo Banner
Ejin Horo Banner, also written as Ejin Horo Qi , is a banner under the administration of Ordos City, in the Inner Mongolia Autonomous Region, People's Republic of China...

 in north China's Inner Mongolia autonomous region. Shenhua eventually intends to expand the facility to 5 million tons per year (roughly 102000 oilbbl/d). The Shenhua Group also expects to complete a 6 Million ton per year (3 Million TPY first phase) coal-to-fuel project using its own Fischer Tropsch indirect conversion technology next to the Inner Mongolia plant in the third quarter of 2009. In September 2011, Shenhua reported profitable operation of its new CTL plant during the first half of the year 2011. The total production of the liquid fuel during that period was 470,000 t and the cost were equivalent to oil price of 60 USD per barel.

Yankuang expects to break ground shortly on a 22000 oilbbl/d (1 million ton per year) indirect synthetic fuels project. Final products will include 780,800 tons of diesel, 258,400 of naphtha, 56,480 of LPG.

United States


In the United States, a number of different synthetic fuels projects are moving forward, with the first expected to enter commercial operation starting in 2013.

American Clean Coal Fuels, in their Illinois Clean Fuels project, is developing a 30000 oilbbl/d Fischer Tropsch biomass and coal to liquids project with carbon capture and sequestration in Oakland Illinois.

Baard Energy, in their Ohio River Clean Fuels project, are developing a 53000 oilbbl/d Fischer Tropsch coal and biomass to liquids project with the carbon capture and sequestration. Pending close of a financing package, Baard hopes to begin on site preparation work before the end of 2009, with plant construction starting in 2010. Initial project startup is anticipated in 2013, with full production capacity targeted in 2015.

Rentech is developing a 29600 oilbbl/d Fischer Tropsch coal and biomass to liquids plant with carbon capture and sequestration in Natchez Mississippi. The project is in the permitting phase, with receipt of permits anticipated by Rentech in 2010.

DKRW is developing a 15000 oilbbl/d Fischer Tropsch coal to liquids plant with carbon capture and sequestration in Medicine Bow Wyoming. The project is expected to begin operation in 2013.

Germany


Choren Industries in Freiburg, Germany has the only operational Biomass to Liquids (BTL) demonstration plant that produces 300 barrels of Fischer Tropsch fuels per day.

Aviation fuel


An effort has been undertaken to certify various synthetic fuels for use in US and international aviation fleets. This is being led by an industry coalition known as the Commercial Aviation Alternative Fuels Initiative
Commercial Aviation Alternative Fuels Initiative
CAAFI is a cooperative effort among interested stakeholders to bring commercially viable, environmentally friendly alternative aviation fuels to market...

(CAAFI), also supported by a parallel initiative under way in the US Air Force to certify synthetic fuels for use in all aviation platforms. The US Air Force has certified 99% of it fleet for use with a 50/50 blend of conventional and FT Synthetic Fuel. The CAAFI initiative has also succeeded in achieving full ASTM certification for a 50/50 blend of both FT-SPK and HEFA synthetic fuels for use in civilian aviation platforms.

Sasol has announced that they have achieved the first approval for 100% synthetic jet fuel use sanctioned by global aviation fuel specification authorities.

On 12 October 2009, a Qatar Airways
Qatar Airways
Qatar Airways Company Q.C.S.C. , operating as Qatar Airways, is the flag carrier of Qatar. Headquartered in the Qatar Airways Tower in Doha, it operates a hub-and-spoke network, linking over 100 international destinations from its base in Doha, using a fleet of over 100 aircraft...

 Airbus A340-600 conducted a the world's first commercial passenger flight using a mixture of kerosene and synthetic Gas-to-Liquid fuel in its flight from London's Gatwick Airport to Doha.

On 15 July 2011 Lufthansa has launched a 6 month biofuel trial on regular scheduled flights. The route selected for the test flights is Hamburg-Frankfurt-Hamburg and it will be covered by an Airbus 321 with the registration D-AIDG.

JBUFF (Joint Battlespace Use Fuel of the Future) fuel


Future blends and fuel formulations may result in a JBUFF (Joint Battlespace Use Fuel of the Future) or a single battlespace fuel that can be used in both diesel and jet fuel application. A JBUFF fuel will allow for rapid deployment and logistic enhancement for military and emergency aid environments where various types of equipment can be operated with one fuel in place of several types of fuel.

Initial consumers


In addition to their certification efforts, the United States Air Force has publicly stated their intention to fuel half of their domestic US flights with synthetic fuel by 2016. The commercial aviation industry, working with potential suppliers via CAAFI
Commercial Aviation Alternative Fuels Initiative
CAAFI is a cooperative effort among interested stakeholders to bring commercially viable, environmentally friendly alternative aviation fuels to market...

, is also pushing hard to secure sources of fuel.

The United States Department of Energy
United States Department of Energy
The United States Department of Energy is a Cabinet-level department of the United States government concerned with the United States' policies regarding energy and safety in handling nuclear material...

 projects that domestic consumption of synthetic fuel made from coal and natural gas will rise to 3.7 Moilbbl/d in 2030 based on a price of $57 per barrel of high sulfur crude.

Non-transportation "synfuel"


Numerous American companies (TECO, Progress Energy
Progress Energy Inc
Progress Energy , headquartered in Raleigh, N.C., is a Fortune 500 energy company with more than 21,000 megawatts of generation capacity and $9 billion in annual revenues. Progress Energy includes two major electric utilities that serve approximately 3.1 million customers in the Carolinas and...

, DTE Energy
DTE Energy
DTE Energy Co. is a Detroit, Michigan-based utility incorporated in 1995 involved in the development and management of energy-related businesses and services nationwide....

, Marriott
Marriott International
Marriott International, Inc. is a worldwide operator and franchisor of a broad portfolio of hotels and related lodging facilities. Founded by J. Willard Marriott, the company is now led by son J.W. Marriott, Jr...

) have also taken advantage of coal-based synfuel tax credits established in the 1970s, although many of the products qualifying for the subsidy are not true synthetic fuels.

The coal industry uses the credit to increase profits on coal-burning powerplants by introducing a "pre-treatment" process that satisfies the technical requirements, then burns the result the same as it would burn coal. Sometimes the amount gained in the tax credit is a major factor in the economic operation of the plant. The synfuel tax credit has been used primarily in this manner since the cheap gas prices of the 1980s
1980s oil glut
The 1980s oil glut was a serious surplus of crude oil caused by falling demand following the 1970s Energy Crisis. The world price of oil, which had peaked in 1980 at over US$35 per barrel , fell in 1986 from $27 to below $10...

 stopped any major efforts to create a transportation fuel with the credit, and its continuation is seen as a major "pork project" win for coal industry lobbyists, costing $9 billion per annum. The total production of such synfuels in the United States was an estimated 73 million tons in 2002.

The synthetic fuel tax credit, Section 45K, under which these activities occurred, expired 31 December 2007.

Economics


The economics of synthetic fuel manufacture vary greatly depending the feedstock used, the precise process employed, site characteristics such as feedstock and transportation costs, and the cost of additional equipment required to control emissions. The examples described below indicate a wide range of production costs between $20/BBL for large-scale gas-to-liquids, to as much as $240/BBL for small-scale biomass-to-liquids + Carbon Capture and Sequestration.

In order to be economically viable, projects must do much better than just being competitive head-to-head with oil. They must also generate a sufficient return on investment to justify the capital investment in the project.

GTL economics


A synthetic fuel manufactured from natural gas (GTL), without CCS, in a large scale plant in the Middle East (where gas is relatively inexpensive), is expected to be competitive with oil down to approximately $20 per barrel.

Recent advances by the oil company Shell have seen synthetic fuels start to become profitable. The company is building a GTL (gas-to-liquid) plant in Qatar, due to come online in 2011. It will be capable of producing 300000 oilbbl/d of synthetic fuels and other products, using natural gas as a feedstock. Their spokesman claims the process will remain competitive with traditional diesel unless the price of crude falls below $20 per barrel.

CTL/CBTL/BTL economics


According to a December 2007 study, a medium scale (30,000 BPD) coal-to-liquids plant (CTL) sited in the US using bituminous coal, is expected to be competitive with oil down to roughly $52–56/bbl crude-oil equivalent. Adding carbon capture and sequestration to the project was expected to add an additional $10/BBL to the required selling price, though this may be offset by revenues from enhanced oil recovery
Enhanced oil recovery
Enhanced Oil Recovery is a generic term for techniques for increasing the amount of crude oil that can be extracted from an oil field...

, or by tax credits, or the eventual sale of carbon credits.

A recent NETL study examined the relative economics of a number of different process configurations for the production of indirect FT fuels using biomass, coal, and CCS. This study determined a price at which the plant would not only be profitable, abut also make a sufficient return to yield a 20% return on the equity investment required to build the plant.


This chapter details an analysis which derives the Required Selling Price (RSP) of the FT diesel fuels produced in order to determine the economic feasibility and relative competitiveness of the different plant options. A sensitivity analysis was performed to determine how carbon control regulations such as an emissions trading scheme for transportation fuels would affect the price of both petroleum-derived diesel and FT diesel from the different plants. The key findings of these analyses were:
(1) CTL plants equipped with CCS are competitive at crude oil prices as low as $86 per barrel and have less life cycle GHG emissions than petroleum-derived diesel. These plants become more economically competitive as carbon prices increase.
(2) The incremental cost of adding simple CCS is very low (7 cents per gallon) because capture is an inherent part of the FT process. This becomes the economically preferred option at carbon prices above $5/mteq.27
(3) BTL systems are hindered by limited biomass availability which affects the maximum plant size, thereby limiting potential economies of scale. This, combined with relatively high biomass costs results in FT diesel prices which are double that of other configurations: $6.45 to $6.96/gal compared to $2.56 to $2.82/gal for CTL and 15wt% CBTL systems equipped with CCS.

The conclusion reached based on these findings was that both the CTL with CCS and the 8wt% to 15wt% CBTL with CCS configurations may offer the most pragmatic solutions to the nation’s energy strategy dilemma: GHG emission reductions which are significant (5% to 33% below the petroleum baseline) at diesel RSPs that are only half as much as the BTL options ($2.56 to $2.82 per gallon compared to $6.45 to $6.96 per gallon for BTL). These options are economically feasible when crude oil prices are $86 to $95 per barrel.


These economics can change in the event that plentiful low-cost biomass sources can be found, lowing the cost of biomass inputs, and improving economies of scale.

Economics for solid feedstock indirect FT process plants are further confused by carbon regulation. Generally, since permitting a CTL plant without CCS will likely be impossible, and CTL+CCS plants have a lower carbon footprint than conventional fuels, carbon regulation is expected to be balance-positive for synthetic fuel production. But it impacts the economics of different process configurations in different ways. The NETL study picked a blended CBTL process using 5-15% biomass alongside coal as the most economical in a range of carbon price and probable future regulation scenarios. Unfortunately, because of scale and cost constraints, pure BTL processes did not score well until very high carbon prices were assumed, though again this may improve with better feedstocks and more efficient larger scale projects.

Chinese direct coal liquefaction economics


News reports have indicated an anticipated cost of production of less than $30 per barrel, based on a direct coal liquefaction process, and a coal mining cost of under $10/ton.

Security considerations


A central consideration for the development of synthetic fuel is the security factor of securing domestic fuel supply from domestic biomass and coal. Nations that are rich in biomass and coal can use synthetic fuel to off-set their use of petroleum derived fuels and foreign oil.

Environmental considerations


The environmental footprint of a given synthetic fuel varies greatly depending on which process is employed, what feedstock is used, what pollution controls are employed, and what the transportation distance and method are for both feedstock procurement and end-product distribution.

In many locations, project development will not be possible due to permitting restrictions if a process design is chosen that does not meet local requirements for clean air, water, and increasingly, lifecycle carbon emissions.

Lifecycle green house gas emissions


Among different indirect FT synthetic fuels production technologies, potential emissions of greenhouse gasses vary greatly. Coal to liquids ("CTL") without carbon capture and sequestration ("CCS") is expected to result in a significantly higher carbon footprint than conventional petroleum-derived fuels (+147%). On the other hand, biomass-to-liquids with CCS could deliver a 358% reduction in lifecycle greenhouse gas emissions. Both of these plants fundamentally use gasification
Gasification
Gasification is a process that converts organic or fossil based carbonaceous materials into carbon monoxide, hydrogen, carbon dioxide and methane. This is achieved by reacting the material at high temperatures , without combustion, with a controlled amount of oxygen and/or steam...

 and FT conversion synthetic fuels technology, but they deliver wildly divergent environmental footprints.

Generally, CTL without CCS has a higher greenhouse gas footprint. CTL with CCS has a 9-15% reduction in lifecycle greenhouse gas emissions compared to that of petroleum derived diesel.

CBTL+CCS plants that blend biomass alongside coal while sequestering carbon do progressively better the more biomass is added. Depending on the type of biomass, the assumptions about root storage, and the transportation logistics, at conservatively 40% biomass alongside coal, CBTL+CCS plants achieve a neutral lifecycle greenhouse gas footprint. At more than 40% biomass, they begin to go lifecycle negative, and effectively store carbon in the ground for every gallon of fuels that they produce.

Ultimately BTL plants employing CCS could store massive amounts of carbon while producing transportation fuels from sustainably produced biomass feedstocks, although there are a number of significant economic hurdles, and a few technical hurdles that would have to be overcome to enable the development of such facilities.

Serious consideration must also be given to the type and method of feedstock procurement for either the coal or biomass used in such facilities, as reckless development could exacerbate environmental problems caused by mountaintop removal mining, land use change, fertilizer runoff, food vs. fuels concerns, or many other potential factors. Or they could not. Depending entirely on project-specific factors on a plant-by-plant basis.

A study from U.S. Department of Energy National Energy Technology Laboratory with much more in-depth information of CBTL life-cycle emissions "Affordable Low Carbon Diesel from Domestic Coal and Biomass": http://www.netl.doe.gov/energy-analyses/pubs/CBTL%20Final%20Report.pdf

Hybrid hydrogen-carbon processes have also been proposed recently as another closed-carbon cycle alternative, combining 'clean' electricity, recycled CO, H2 and captured CO2 with biomass as inputs as a way of reducing the biomass needed.

Fuels emissions


The fuels produced by the various synthetic fuels process also have a wide range of potential environmental performance, though they tend to be very uniform based on the type of synthetic fuels process used (i.e. the tailpipe emissions characteristics of Fischer Tropsch diesel tend to be the same, though their lifecycle greenhouse gas footprint can vary substantially based on which plant produced the fuel, depending on feedstock and plant level sequestration considerations.)

In particular, Fischer tropsch diesel and jet fuels deliver dramatic across-the-board reductions in all major criteria pollutants such as SOx, NOx, Particulate Matter, and Hydrocarbon emissions. These fuels, because of their high level of purity and lack of contaminants, further enable the use of advanced emissions control equipment that has been shown to virtually eliminate HC, CO, and PM emissions from diesel vehicles.

In testimony before the Subcommittee on Energy and Environment of the U.S. House of Representatives the following statement was made by a senior scientist from Rentech:
F-T fuels offer numerous benefits to aviation users. The first is an immediate reduction in particulate emissions. F-T jet fuel has been shown in laboratory combusters and engines to reduce PM emissions by 96% at idle and 78% under cruise operation. Validation of the reduction in other turbine engine emissions is still under way. Concurrent to the PM reductions is an immediate reduction in emissions from F-T fuel. F-T fuels inherently reduce emissions because they have higher energy content per carbon content of the fuel, and the fuel is less dense than conventional jet fuel allowing aircraft to fly further on the same load of fuel.


The cleanliness of these FT synthetic fuels is further demonstrated by the fact that they are sufficiently non-toxic and environmentally benign as to be considered biodegradable. This owes primarily to the near-absence of sulfur and extremely low level of aromatics present in the fuel.

Sustainability


One concern commonly raised about the development of synthetic fuels plants is sustainability. Fundamentally, transitioning from oil to coal or natural gas for transportation fuels production is a transition from one inherently depeleteable geologically limited resource to another.

One of the positive defining characteristics of synthetic fuels production is the ability to use multiple feedstocks (coal, gas, or biomass) to produce the same product from the same plant. In the case of hybrid BCTL plants, some facilities are already planning to use a significant biomass component alongside coal. Ultimately, given the right location with good biomass availability, and sufficiently high oil prices, synthetic fuels plants can be transitioned from coal or gas, over to a 100% biomass feedstock. This provides a path forwards to a renewable fuel source and possibly more sustainable, even if the plant originally produced fuels solely from coal, making the infrastructure forwards-compatible even if the original fossil feedstock runs out.

Some synthetic fuels processes can be converted to sustainable production practices more easily than others, depending on the process equipment selected. This is an important design consideration as these facilities are planned and implemented, as additional room must be left in the plant layout to accommodate whatever future materials handling and gasification plant change requirements might be necessary to accommodate a future change in production profile.

See also



  • Gasification
    Gasification
    Gasification is a process that converts organic or fossil based carbonaceous materials into carbon monoxide, hydrogen, carbon dioxide and methane. This is achieved by reacting the material at high temperatures , without combustion, with a controlled amount of oxygen and/or steam...

  • Methanol to gasoline
  • 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...

  • Butanol fuel
    Butanol fuel
    Butanol may be used as a fuel in an internal combustion engine. Because its longer hydrocarbon chain causes it to be fairly non-polar, it is more similar to gasoline than it is to ethanol...

  • 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...

  • Synthetic 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...

  • Synthetic Fuels Corporation
    Synthetic Fuels Corporation
    The Synthetic Fuels Corporation was a U.S. government-funded corporation established in 1980 by the Synthetic Fuels Corporation Act to create a financial bridge for the development and construction of commercial synthetic fuel manufacturing plants that would produce alternatives to imported fossil...

  • 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...

  • Thermal depolymerization
    Thermal depolymerization
    Thermal depolymerization is a depolymerization process using hydrous pyrolysis for the reduction of complex organic materials into light crude oil. It mimics the natural geological processes thought to be involved in the production of fossil fuels...

  • Cracking
    Cracking (chemistry)
    In petroleum geology and chemistry, cracking is the process whereby complex organic molecules such as kerogens or heavy hydrocarbons are broken down into simpler molecules such as light hydrocarbons, by the breaking of carbon-carbon bonds in the precursors. The rate of cracking and the end products...

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

  • Methanol economy
    Methanol economy
    The methanol economy is a suggested future economy in which methanol replaces fossil fuels as a means of energy storage, ground transportation fuel, and raw material for synthetic hydrocarbons and their products. It offers an alternative to the proposed hydrogen economy or ethanol economy.In the...



External links