![Red diesel tank](https://upload.wikimedia.org/wikipedia/commons/6/69/Red_diesel_tank.jpg)
Diesel fuel , also called diesel oil, is any
liquid fuel
Liquid fuels are combustible or energy-generating molecules that can be harnessed to create mechanical energy, usually producing kinetic energy; they also must take the shape of their container. It is the fumes of liquid fuels that are flammable ...
specifically designed for use in a
diesel engine
The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-call ...
, a type of
internal combustion engine
An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combus ...
in which fuel ignition takes place without a spark as a result of compression of the inlet air and then injection of fuel. Therefore, diesel fuel needs good compression ignition characteristics.
The most common type of diesel fuel is a specific
fractional distillate of
petroleum
Petroleum, also known as crude oil, or simply oil, is a naturally occurring yellowish-black liquid mixture of mainly hydrocarbons, and is found in geological formations. The name ''petroleum'' covers both naturally occurring unprocessed crud ...
fuel oil
Fuel oil is any of various fractions obtained from the distillation of petroleum (crude oil). Such oils include distillates (the lighter fractions) and residues (the heavier fractions). Fuel oils include heavy fuel oil, marine fuel oil (MFO), bun ...
, but alternatives that are not derived from petroleum, such as
biodiesel
Biodiesel is a form of diesel fuel derived from plants or animals and consisting of long-chain fatty acid esters. It is typically made by chemically reacting lipids such as animal fat (tallow), soybean oil, or some other vegetable oil with ...
,
biomass to liquid
Biomass to liquid (BtL or BMtL) is a multi-step process of producing synthetic hydrocarbon fuels made from biomass via a thermochemical route.
Main processes
According to a study done by the U.S. Department of Agriculture and the Department of En ...
(BTL) or
gas to liquid
Gas to liquids (GTL) is a refinery process to convert natural gas or other gaseous hydrocarbons into longer-chain hydrocarbons, such as gasoline or diesel fuel. Methane-rich gases are converted into liquid synthetic fuels. Two general strategies ex ...
(GTL) diesel are increasingly being developed and adopted. To distinguish these types, petroleum-derived diesel is sometimes called petrodiesel in some academic circles.
In many countries, diesel fuel is standardised. For example, in the
European Union
The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been des ...
, the standard for diesel fuel is
EN 590 EN 590 is a standard published by the European Committee for Standardization that describes the physical properties that all automotive diesel fuel must meet if it is to be sold in the European Union and several other European countries.
Based on ...
. Diesel fuel has many colloquial names; most commonly, it is simply referred to as ''diesel''. In the
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...
, diesel fuel for on-road use is commonly called ''diesel'' or sometimes ''white diesel'' if required to differentiate it from a tax-advantaged
agricultural-only product containing an identifying coloured dye known as ''red diesel''. The official term for white diesel is ''DERV'', standing for ''diesel-engine road vehicle''. In
Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
, diesel fuel is also known as distillate (not to be confused with
"distillate" in an older sense referring to a different motor fuel), and in
Indonesia
Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...
, it is known as Solar, a trademarked name from the country's national petroleum company
Pertamina. The term gas oil (
French: ''gazole'') is sometimes also used to refer to diesel fuel.
Ultra-low-sulfur diesel
Ultra-low-sulfur diesel (ULSD) is diesel fuel with substantially lowered sulfur content. Since 2006, almost all of the petroleum-based diesel fuel available in Europe and North America has been of a ULSD type.
The move to lower sulfur content allo ...
(ULSD) is a diesel fuel with substantially lowered
sulfur
Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...
contents. As of 2016, almost all of the petroleum-based diesel fuel available in the United Kingdom,
mainland Europe
Continental Europe or mainland Europe is the contiguous continent of Europe, excluding its surrounding islands. It can also be referred to ambiguously as the European continent, – which can conversely mean the whole of Europe – and, by ...
, and
North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
is of a ULSD type.
Before diesel fuel had been standardised, the majority of diesel engines typically ran on cheap
fuel oils
Fuel oil is any of various fractions obtained from the distillation of petroleum (crude oil). Such oils include distillates (the lighter fractions) and residues (the heavier fractions). Fuel oils include heavy fuel oil, marine fuel oil (MFO), bu ...
. These fuel oils are still used in watercraft diesel engines. Despite being specifically designed for diesel engines, diesel fuel can also be used as fuel for several non-diesel engines, for example the
Akroyd engine
The hot-bulb engine is a type of internal combustion engine in which fuel ignites by coming in contact with a red-hot metal surface inside a bulb, followed by the introduction of air (oxygen) compressed into the hot-bulb chamber by the rising p ...
, the
Stirling engine
A Stirling engine is a heat engine that is operated by the cyclic compression and expansion of air or other gas (the ''working fluid'') between different temperatures, resulting in a net conversion of heat energy to mechanical work.
More specif ...
, or boilers for
steam engine
A steam engine is a heat engine that performs mechanical work using steam as its working fluid. The steam engine uses the force produced by steam pressure to push a piston back and forth inside a cylinder. This pushing force can be trans ...
s.
History
Origins
Diesel fuel originated from experiments conducted by German scientist and inventor
Rudolf Diesel
Rudolf Christian Karl Diesel (, ; 18 March 1858 – 29 September 1913) was a German inventor and mechanical engineer who is famous for having invented the diesel engine, which burns diesel fuel; both are named after him.
Early life and educat ...
for his
compression-ignition engine
The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-cal ...
he invented in 1892. Originally, Diesel did not consider using any specific type of fuel, instead, he claimed that the operating principle of his
rational heat motor would work with any kind of fuel in any state of matter. However, both the first diesel engine prototype and the first functional Diesel engine were only designed for liquid fuels.
At first, Diesel tested
crude oil
Petroleum, also known as crude oil, or simply oil, is a naturally occurring yellowish-black liquid mixture of mainly hydrocarbons, and is found in geological formations. The name ''petroleum'' covers both naturally occurring unprocessed crude ...
from
Pechelbronn
Merkwiller-Pechelbronn () is a commune in the Bas-Rhin department in Grand Est in north-eastern France.
It is notable as the original home of oil sands mining.
Oil sands were mined from 1745 in Merkwiller-Pechelbronn, initially under the direc ...
, but soon replaced it with
petrol
Gasoline (; ) or petrol (; ) (see ) is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignited internal combustion engines (also known as petrol engines). It consists mostly of organic c ...
and
kerosene
Kerosene, paraffin, or lamp oil is a combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in aviation as well as households. Its name derives from el, κηρός (''keros'') meaning "wax", and was regi ...
, because crude oil proved to be too viscous, with the main testing fuel for the Diesel engine being kerosene. In addition to that, Diesel experimented with different types of
lamp oil
Kerosene, paraffin, or lamp oil is a combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in aviation as well as households. Its name derives from el, κηρός (''keros'') meaning "wax", and was regi ...
from various sources, as well as different types of petrol and
ligroin, which all worked well as Diesel engine fuels. Later, Diesel tested
coal tar
Coal tar is a thick dark liquid which is a by-product of the production of coke and coal gas from coal. It is a type of creosote. It has both medical and industrial uses. Medicinally it is a topical medication applied to skin to treat psoriasi ...
creosote
Creosote is a category of carbonaceous chemicals formed by the distillation of various tars and pyrolysis of plant-derived material, such as wood or fossil fuel. They are typically used as preservatives or antiseptics.
Some creosote types were ...
,
paraffin oil, crude oil,
gasoil, and
fuel oil
Fuel oil is any of various fractions obtained from the distillation of petroleum (crude oil). Such oils include distillates (the lighter fractions) and residues (the heavier fractions). Fuel oils include heavy fuel oil, marine fuel oil (MFO), bun ...
, which eventually worked as well. In Scotland and France,
shale oil
Shale oil is an unconventional oil produced from oil shale rock fragments by pyrolysis, hydrogenation, or thermal dissolution. These processes convert the organic matter within the rock (kerogen) into synthetic oil and gas. The resulting oil c ...
was used as fuel for the first 1898 production Diesel engines because other fuels were too expensive. In 1900, the French Otto society built a Diesel engine for the use with crude oil, which was exhibited at the
1900 Paris Exposition[Rudolf Diesel: ''Die Entstehung des Dieselmotors'', Springer, Berlin/Heidelberg 1913, p. 115] and the 1911 World's Fair in Paris. The engine actually ran on
peanut oil
Peanut oil, also known as groundnut oil or arachis oil, is a vegetable oil derived from peanuts. The oil usually has a mild or neutral flavor but, if made with roasted peanuts, has a stronger peanut flavor and aroma. It is often used in America ...
instead of crude oil, and no modifications were necessary for peanut oil operation.
During his first Diesel engine tests, Diesel also used
illuminating gas
The history of gaseous fuel, important for lighting, heating, and cooking purposes throughout most of the 19th century and the first half of the 20th century, began with the development of analytical and pneumatic chemistry in the 18th century. ...
as fuel, and managed to build functional designs, both with and without pilot injection. According to Diesel, neither was a coal-dust–producing industry existent, nor was fine, high quality coal-dust commercially available in the late 1890s. This is the reason why the Diesel engine was never designed or planned as a coal-dust engine. Only in December 1899, did Diesel test a coal-dust prototype, which used external mixture formation and liquid fuel pilot injection. This engine proved to be functional, but suffered from piston ring failure after a very few minutes due to coal dust deposition.
Since the 20th century
Before diesel fuel had been standardised, diesel engines typically ran on cheap fuel oils. In the United States, these were distilled from petroleum, whereas in Europe, coal-tar creosote oil was used. Some diesel engines were fuelled with mixtures of several different fuels, such as petrol, kerosine, rapeseed oil, or lubricating oil, because they were untaxed and thus cheap. The introduction of motor-vehicle diesel engines, such as the
Mercedes-Benz OM 138
The Mercedes-Benz OM 138 is a diesel engine manufactured by Daimler-Benz. In total, 5,719 units were produced between 1935 and 1940.According to Oswald, 1,082 engines were made for the L 1100 and 2,670 were made for the L 1500. Daimler says t ...
, in the 1930s meant that higher quality fuels with proper ignition characteristics were needed. At first no improvements were made to motor-vehicle diesel fuel quality. After World War II, the first modern high quality diesel fuels were standardised. These standards were, for instance, the DIN 51601, VTL 9140-001, and NATO F 54 standards.
[Hans Christian Graf von Seherr-Thoß (auth.): Die Technik des MAN Nutzfahrzeugbaus. In: MAN Nutzfahrzeuge AG (ed.): Leistung und Weg: Zur Geschichte des MAN Nutzfahrzeugbaus. Springer, Berlin/Heidelberg 1991. . p. 437] In 1993, the DIN 51601 was rendered obsolete by the new EN 590 standard, which has been used in the European Union ever since. In sea-going watercraft, where diesel propulsion had gained prevalence by the late 1970s due to increasing fuel costs caused by the
1970s energy crisis, cheap
heavy fuel oil
Heavy Fuel Oil (HFO) is a category of fuel oils of a tar-like consistency. Also known as bunker fuel, or residual fuel oil, HFO is the result or remnant from the distillation and cracking process of petroleum. For this reason, HFO is contaminate ...
s are still used instead of conventional motor-vehicle diesel fuel. These heavy fuel oils (often called
Bunker C
Fuel oil is any of various fractions obtained from the distillation of petroleum (crude oil). Such oils include distillates (the lighter fractions) and residues (the heavier fractions). Fuel oils include heavy fuel oil, marine fuel oil (MFO), bun ...
) can be used in diesel-powered and steam-powered vessels.
[Günter Mau: Handbuch Dieselmotoren im Kraftwerks- und Schiffsbetrieb, Springer-Vieweg, Braunschweig/Wiesbaden 1984, . p. 13]
Types
Diesel fuel is produced from various sources, the most common being
petroleum
Petroleum, also known as crude oil, or simply oil, is a naturally occurring yellowish-black liquid mixture of mainly hydrocarbons, and is found in geological formations. The name ''petroleum'' covers both naturally occurring unprocessed crud ...
. Other sources include
biomass
Biomass is plant-based material used as a fuel for heat or electricity production. It can be in the form of wood, wood residues, energy crops, agricultural residues, and waste from industry, farms, and households. Some people use the terms bi ...
,
animal fat,
biogas
Biogas is a mixture of gases, primarily consisting of methane, carbon dioxide and hydrogen sulphide, produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste and food waste. It is a ...
,
natural gas
Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbo ...
, and
coal liquefaction
Coal liquefaction is a process of converting coal into liquid hydrocarbons: liquid fuels and petrochemicals. This process is often known as "Coal to X" or "Carbon to X", where X can be many different hydrocarbon-based products. However, the most ...
.
Petroleum diesel
![essodiesel](https://upload.wikimedia.org/wikipedia/commons/1/1d/Essodiesel.jpg)
Petroleum diesel, also called petrodiesel, fossil diesel, or mineral diesel, is the most common type of diesel fuel. It is produced from the
fractional distillation
Fractional distillation is the separation of a mixture into its component parts, or fractions. Chemical compounds are separated by heating them to a temperature at which one or more fractions of the mixture will vaporize. It uses distillation to ...
of
crude oil
Petroleum, also known as crude oil, or simply oil, is a naturally occurring yellowish-black liquid mixture of mainly hydrocarbons, and is found in geological formations. The name ''petroleum'' covers both naturally occurring unprocessed crude ...
between at
atmospheric pressure
Atmospheric pressure, also known as barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1013.25 millibars, ...
, resulting in a mixture of carbon chains that typically contain between 9 and 25
carbon
Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent
In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with o ...
atom
Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and a number of neutrons. Only the most common variety of hydrogen has no neutrons.
Every solid, liquid, gas, and ...
s per
molecule
A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioch ...
.
Synthetic diesel
Synthetic diesel can be produced from any carbonaceous material, including biomass, biogas, natural gas, coal and many others. The raw material is gasified into
synthesis gas
Syngas, or synthesis gas, is a mixture of hydrogen and carbon monoxide, in various ratios. The gas often contains some carbon dioxide and methane. It is principly used for producing ammonia or methanol. Syngas is combustible and can be used ...
, which after purification is converted by the
Fischer–Tropsch process
The Fischer–Tropsch process is a collection of chemical reactions that converts a mixture of carbon monoxide and hydrogen, known as syngas, into liquid hydrocarbons. These reactions occur in the presence of metal catalysts, typically at temperatu ...
to a synthetic diesel.
The process is typically referred to as
biomass-to-liquid
Biomass to liquid (BtL or BMtL) is a multi-step process of producing synthetic hydrocarbon fuels made from biomass via a thermochemical route.
Main processes
According to a study done by the U.S. Department of Agriculture and the Department of E ...
(BTL),
gas-to-liquid (GTL) or
coal-to-liquid
Coal liquefaction is a process of converting coal into liquid hydrocarbons: liquid fuels and petrochemicals. This process is often known as "Coal to X" or "Carbon to X", where X can be many different hydrocarbon-based products. However, the most c ...
(CTL), depending on the raw material used.
Paraffinic synthetic diesel generally has a near-zero content of sulfur and very low aromatics content, reducing unregulated emissions of toxic hydrocarbons, nitrous oxides and particulate matter (PM).
Biodiesel
Biodiesel
Biodiesel is a form of diesel fuel derived from plants or animals and consisting of long-chain fatty acid esters. It is typically made by chemically reacting lipids such as animal fat (tallow), soybean oil, or some other vegetable oil with ...
is obtained from
vegetable oil
Vegetable oils, or vegetable fats, are oils extracted from seeds or from other parts of fruits. Like animal fats, vegetable fats are ''mixtures'' of triglycerides. Soybean oil, grape seed oil, and cocoa butter are examples of seed oils, or f ...
or animal fats (bio
lipid
Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include ...
s) which are mainly
fatty acid methyl ester Fatty acid methyl esters (FAME) are a type of fatty acid ester that are derived by transesterification of fats with methanol. The molecules in biodiesel are primarily FAME, usually obtained from vegetable oils by transesterification. They are used ...
s (FAME), and
transesterified
In organic chemistry, transesterification is the process of exchanging the organic group R″ of an ester with the organic group R' of an alcohol. These reactions are often catalyzed by the addition of an acid or base catalyst. The reaction ca ...
with
methanol
Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical and the simplest aliphatic alcohol, with the formula C H3 O H (a methyl group linked to a hydroxyl group, often abbreviated as MeOH). It is a ...
. It can be produced from many types of oils, the most common being
rapeseed
Rapeseed (''Brassica napus ''subsp.'' napus''), also known as rape, or oilseed rape, is a bright-yellow flowering member of the family Brassicaceae (mustard or cabbage family), cultivated mainly for its oil-rich seed, which naturally contains a ...
oil (rapeseed methyl ester, RME) in Europe and
soybean oil
Soybean oil (British English: soyabean oil) is a vegetable oil extracted from the seeds of the soybean (''Glycine max''). It is one of the most widely consumed cooking oils and the second most consumed vegetable oil. As a drying oil, processed s ...
(soy methyl ester, SME) in the US. Methanol can also be replaced with ethanol for the transesterification process, which results in the production of ethyl esters. The transesterification processes use catalysts, such as sodium or potassium hydroxide, to convert vegetable oil and methanol into biodiesel and the undesirable byproducts glycerine and water, which will need to be removed from the fuel along with methanol traces. Biodiesel can be used pure (B100) in engines where the manufacturer approves such use, but it is more often used as a mix with diesel, BXX where XX is the biodiesel content in percent.
[Bosch Automotive Handbook, 6th edition, pp. 327–328]
FAME used as fuel is specified in
DIN EN 14214 and ASTM D6751 standards.
Fuel Injection Equipment (FIE) manufacturers have raised several concerns regarding biodiesel, identifying FAME as being the cause of the following problems: corrosion of fuel injection components, low-pressure fuel system blockage, increased dilution and
polymerization
In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. There are many fo ...
of engine sump oil, pump seizures due to high fuel viscosity at low temperature, increased injection pressure, elastomeric seal failures and fuel injector spray blockage. Pure biodiesel has an energy content about 5–10% lower than petroleum diesel. The loss in power when using pure biodiesel is 5–7%.
Unsaturated fatty acid
In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, f ...
s are the source for the lower oxidation stability. They react with oxygen and form peroxides and result in degradation byproducts, which can cause sludge and lacquer in the fuel system.
As biodiesel contains low levels of sulfur, the emissions of
sulfur oxide
Sulfur oxide refers to many types of sulfur and oxygen containing compounds such as SO, SO2, SO3, S7O2, S6O2, S2O2, etc.
Sulfur oxide (SO''x'') refers to one or more of the following:
* Lower sulfur oxides (S''n''O, S7O2 and S6O2)
* Sulfur mono ...
s and
sulfate
The sulfate or sulphate ion is a polyatomic anion with the empirical formula . Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many ...
s, major components of
acid rain, are low. Use of biodiesel also results in reductions of unburned hydrocarbons,
carbon monoxide
Carbon monoxide (chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simple ...
(CO), and particulate matter. CO emissions using biodiesel are substantially reduced, on the order of 50% compared to most petrodiesel fuels. The exhaust emissions of particulate matter from biodiesel have been found to be 30% lower than overall particulate matter emissions from petrodiesel. The exhaust emissions of total hydrocarbons (a contributing factor in the localized formation of smog and ozone) are up to 93% lower for biodiesel than diesel fuel.
Biodiesel also may reduce health risks associated with petroleum diesel. Biodiesel emissions showed decreased levels of
polycyclic aromatic hydrocarbon
A polycyclic aromatic hydrocarbon (PAH) is a class of organic compounds that is composed of multiple aromatic rings. The simplest representative is naphthalene, having two aromatic rings and the three-ring compounds anthracene and phenanthrene. ...
(PAH) and nitrated PAH compounds, which have been identified as potential
carcinogen
A carcinogen is any substance, radionuclide, or radiation that promotes carcinogenesis (the formation of cancer). This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes. Several radioactive subs ...
s. In recent testing, PAH compounds were reduced by 75–85%, except for
benz(a)anthracene
Benz 'a''nthracene or benzo 'a''nthracene is a polycyclic aromatic hydrocarbon with the chemical formula C18H12. It is produced during incomplete combustion of organic matter.
Benz 'a''nthracene is one of carcinogenic constituents of tobacco sm ...
, which was reduced by roughly 50%. Targeted nPAH compounds were also reduced dramatically with biodiesel fuel, with
2-nitrofluorene and
1-nitropyrene reduced by 90%, and the rest of the nPAH compounds reduced to only trace levels.
Hydrogenated oils and fats
This category of diesel fuels involves converting the
triglyceride
A triglyceride (TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids (from ''wikt:tri-#Prefix, tri-'' and ''glyceride'').
Triglycerides are the main constituents of body fat in humans and other ...
s in vegetable oil and animal fats into alkanes by
refining and
hydrogenation
Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organ ...
, such as
Neste Renewable Diesel Neste Renewable Diesel (formerly NExBTL) is a vegetable oil refining fuel production process commercialized by the Finnish oil and refining company Neste. Whether as an admixture or in its pure form, Neste Renewable Diesel is able to supplement or ...
or
H-Bio. The produced fuel has many properties that are similar to synthetic diesel, and are free from the many disadvantages of FAME.
DME
Dimethyl ether
Dimethyl ether (DME; also known as methoxymethane) is the organic compound with the formula CH3OCH3,
(sometimes ambiguously simplified to C2H6O as it is an isomer of ethanol). The simplest ether, it is a colorless gas that is a useful precursor ...
, DME, is a synthetic, gaseous diesel fuel that results in clean combustion with very little soot and reduced emissions.
Storage
In the US, diesel is recommended to be stored in a yellow container to differentiate it from
kerosene
Kerosene, paraffin, or lamp oil is a combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in aviation as well as households. Its name derives from el, κηρός (''keros'') meaning "wax", and was regi ...
, which is typically kept in blue containers, and
gasoline
Gasoline (; ) or petrol (; ) (see ) is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignited internal combustion engines (also known as petrol engines). It consists mostly of organic co ...
(petrol), which is typically kept in red containers.
In the UK, diesel is normally stored in a black container to differentiate it from unleaded or leaded petrol, which are stored in green and red containers, respectively.
Standards
The diesel engine is a multifuel engine and can run on a huge variety of fuels. However, development of high-performance, high-speed diesel engines for cars and lorries in the 1930s meant that a proper fuel specifically designed for such engines was needed: diesel fuel. In order to ensure consistent quality, diesel fuel is standardised; the first standards were introduced after World War II.
Typically, a standard defines certain properties of the fuel, such as
cetane number
Cetane number (cetane rating) is an indicator of the combustion speed of diesel fuel and compression needed for ignition. It plays a similar role for diesel as octane rating does for gasoline. The CN is an important factor in determining the quali ...
,
density
Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematical ...
,
flash point
The flash point of a material is the "lowest liquid temperature at which, under certain standardized conditions, a liquid gives off vapours in a quantity such as to be capable of forming an ignitable vapour/air mixture". (EN 60079-10-1)
The fl ...
,
sulphur
Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...
content, or biodiesel content. Diesel fuel standards include:
Diesel fuel
*
EN 590 EN 590 is a standard published by the European Committee for Standardization that describes the physical properties that all automotive diesel fuel must meet if it is to be sold in the European Union and several other European countries.
Based on ...
(European Union)
*ASTM D975 (United States)
*GOST R 52368 (Russia; equivalent to EN 590)
*NATO F 54 (NATO; equivalent to EN 590)
*DIN 51601 (West Germany; obsolete)
Biodiesel fuel
*
EN 14214
EN 14214 is a standard published by the European Committee for Standardization that describes the requirements and test methods for FAME - the most common type of biodiesel.
The technical definition of biodiesel is a fuel suitable for use in comp ...
(European Union)
*ASTM D6751 (United States)
*CAN/CGSB-3.524 (Canada)
Measurements and pricing
Cetane number
The principal measure of diesel fuel quality is its
cetane number
Cetane number (cetane rating) is an indicator of the combustion speed of diesel fuel and compression needed for ignition. It plays a similar role for diesel as octane rating does for gasoline. The CN is an important factor in determining the quali ...
. A cetane number is a measure of the delay of ignition of a diesel fuel.
A higher cetane number indicates that the fuel ignites more readily when sprayed into hot compressed air.
European (EN 590 standard) road diesel has a minimum cetane number of 51. Fuels with higher cetane numbers, normally "premium" diesel fuels with additional cleaning agents and some synthetic content, are available in some markets.
Fuel value and price
About 86.1% of diesel fuel mass is carbon, and when burned, it offers a net heating value of 43.1 MJ/kg as opposed to 43.2 MJ/kg for gasoline. Due to the higher density, diesel fuel offers a higher volumetric energy density: the density of EN 590 diesel fuel is defined as at , about 9.0-13.9% more than EN 228 gasoline (petrol)'s at 15 °C, which should be put into consideration when comparing volumetric fuel prices. The emissions from diesel are 73.25 g/MJ, just slightly lower than for gasoline at 73.38 g/MJ.
Diesel fuel is generally simpler to refine from petroleum than gasoline, and contains hydrocarbons having a boiling point in the range of . Additional refining is required to remove sulfur, which contributes to a sometimes higher cost. In many parts of the United States and throughout the United Kingdom and Australia, diesel fuel may be priced higher than petrol per
gallon
The gallon is a unit of volume in imperial units and United States customary units. Three different versions are in current use:
*the imperial gallon (imp gal), defined as , which is or was used in the United Kingdom, Ireland, Canada, Austr ...
or
litre
The litre (international spelling) or liter (American English spelling) (SI symbols L and l, other symbol used: ℓ) is a metric unit of volume. It is equal to 1 cubic decimetre (dm3), 1000 cubic centimetres (cm3) or 0.001 cubic metre (m3). ...
. Reasons for higher-priced diesel include the shutdown of some refineries in the
Gulf of Mexico
The Gulf of Mexico ( es, Golfo de México) is an oceanic basin, ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of ...
, diversion of mass refining capacity to gasoline production, and a recent transfer to
ultra-low-sulfur diesel
Ultra-low-sulfur diesel (ULSD) is diesel fuel with substantially lowered sulfur content. Since 2006, almost all of the petroleum-based diesel fuel available in Europe and North America has been of a ULSD type.
The move to lower sulfur content allo ...
(ULSD), which causes infrastructural complications. In Sweden, a diesel fuel designated as MK-1 (class 1 environmental diesel) is also being sold. This is a ULSD that also has a lower aromatics content, with a limit of 5%. This fuel is slightly more expensive to produce than regular ULSD. In Germany, the fuel tax on diesel fuel is about 28% lower than the petrol fuel tax.
Taxation
Diesel fuel is similar to
heating oil, which is used in
central heating
A central heating system provides warmth to a number of spaces within a building from one main source of heat. It is a component of heating, ventilation, and air conditioning (short: HVAC) systems, which can both cool and warm interior spaces.
...
. In Europe, the United States, and Canada,
tax
A tax is a compulsory financial charge or some other type of levy imposed on a taxpayer (an individual or legal entity) by a governmental organization in order to fund government spending and various public expenditures (regional, local, or n ...
es on diesel fuel are higher than on heating oil due to the
fuel tax
A fuel tax (also known as a petrol, gasoline or gas tax, or as a fuel duty) is an excise tax imposed on the sale of fuel. In most countries the fuel tax is imposed on fuels which are intended for transportation. Fuels used to power agricultural v ...
, and in those areas, heating oil is marked with
fuel dyes
Fuel dyes are dyes added to fuels, as in some countries it is required by law to dye a low-tax fuel to deter its use in applications intended for higher-taxed ones. Untaxed fuels are referred to as "dyed", while taxed ones are called "clear" or "w ...
and trace chemicals to prevent and detect
tax fraud
Tax evasion is an illegal attempt to defeat the imposition of taxes by individuals, corporations, trusts, and others. Tax evasion often entails the deliberate misrepresentation of the taxpayer's affairs to the tax authorities to reduce the taxp ...
. "Untaxed" diesel (sometimes called "off-road diesel" or "red diesel" due to its red dye) is available in some countries for use primarily in agricultural applications, such as fuel for tractors, recreational and utility vehicles or other
noncommercial
A non-commercial (also spelled noncommercial) activity is an activity that does not, in some sense, involve commerce, at least relative to similar activities that do have a commercial objective or emphasis. For example, advertising-free community ...
vehicles that do not use
public road
A highway is any public or private road or other public way on land. It is used for major roads, but also includes other public roads and public tracks. In some areas of the United States, it is used as an equivalent term to controlled-access ...
s. This fuel may have sulfur levels that exceed the limits for road use in some countries (e.g. US).
This untaxed diesel is dyed red for identification,
[ Cited as 26 CFR 48.4082-1. This regulation implements .] and using this untaxed diesel fuel for a typically taxed purpose (such as driving use), the user can be fined (e.g. US$10,000 in the US). In the United Kingdom, Belgium and the Netherlands, it is known as
red diesel
Fuel dyes are dyes added to fuels, as in some countries it is required by law to dye a low-tax fuel to deter its use in applications intended for higher-taxed ones. Untaxed fuels are referred to as "dyed", while taxed ones are called "clear" or "w ...
(or gas oil), and is also used in
agricultural
Agriculture or farming is the practice of cultivating Plant, plants and livestock. Agriculture was the key development in the rise of Sedentism, sedentary human civilization, whereby farming of Domestication, domesticated species created food ...
vehicles, home heating tanks, refrigeration units on vans/trucks which contain perishable items such as food and medicine and for marine craft. Diesel fuel, or marked gas oil is dyed green in the Republic of Ireland and Norway. The term "diesel-engined road vehicle" (DERV) is used in the UK as a synonym for unmarked road diesel fuel. In India, taxes on diesel fuel are lower than on petrol, as the majority of the transportation for grain and other essential commodities across the country runs on diesel.
Taxes on
biodiesel
Biodiesel is a form of diesel fuel derived from plants or animals and consisting of long-chain fatty acid esters. It is typically made by chemically reacting lipids such as animal fat (tallow), soybean oil, or some other vegetable oil with ...
in the US vary between states. Some states (Texas, for example) have no tax on biodiesel and a reduced tax on biodiesel blends equivalent to the amount of biodiesel in the blend, so that B20 fuel is taxed 20% less than pure petrodiesel. Other states, such as North Carolina, tax biodiesel (in any blended configuration) the same as petrodiesel, although they have introduced new incentives to producers and users of all biofuels.
Uses
Diesel fuel is mostly used in high-speed diesel engines, especially motor-vehicle (e.g. car, lorry) diesel engines, but not all diesel engines run on diesel fuel. For example, large two-stroke watercraft engines typically use heavy fuel oils instead of diesel fuel,
and certain types of diesel engines, such as MAN
M-System
The MAN M-System, also referred to as M-Process and M combustion process, is a direct injection system for Diesel engines. In M-System engines, the fuel is injected ''onto'' the walls of the combustion chamber that is solely located inside the pi ...
engines, are designed to run on petrol with knock resistances of up to 86 RON. On the other hand,
gas turbine
A gas turbine, also called a combustion turbine, is a type of continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part (known as the gas generator or core) and are, in the directio ...
and some other types of internal combustion engines, and
external combustion engine
An external combustion engine (EC engine) is a reciprocating heat engine where a working fluid, contained internally, is heated by combustion in an external source, through the engine wall or a heat exchanger. The fluid then, by expanding an ...
s, can also be designed to take diesel fuel.
The
viscosity
The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water.
Viscosity quantifies the inte ...
requirement of diesel fuel is usually specified at 40 °C.
A disadvantage of diesel fuel in cold climates is that its viscosity increases as the temperature decreases, changing it into a
gel
A gel is a semi-solid that can have properties ranging from soft and weak to hard and tough. Gels are defined as a substantially dilute cross-linked system, which exhibits no flow when in the steady-state, although the liquid phase may still dif ...
(see
Compression Ignition – Gelling) that cannot flow in fuel systems. Special
low-temperature diesel contains additives to keep it liquid at lower temperatures.
On-road vehicles
Truck
A truck or lorry is a motor vehicle designed to transport cargo, carry specialized payloads, or perform other utilitarian work. Trucks vary greatly in size, power, and configuration, but the vast majority feature body-on-frame construction ...
s and
bus
A bus (contracted from omnibus, with variants multibus, motorbus, autobus, etc.) is a road vehicle that carries significantly more passengers than an average car or van. It is most commonly used in public transport, but is also in use for cha ...
es, which were often otto-powered in the 1920s through 1950s, are now almost exclusively diesel-powered. Due to its ignition characteristics, diesel fuel is thus widely used in these vehicles. Since diesel fuel is not well-suited for otto engines, passenger cars, which often use otto or otto-derived engines, typically run on petrol instead of diesel fuel. However, especially in Europe and India, many passenger cars have, due to better engine efficiency,
diesel engines, and thus run on regular diesel fuel.
Railroad
Diesel displaced coal and fuel oil for steam-powered vehicles in the latter half of the 20th century, and is now used almost exclusively for the combustion engines of self-powered rail vehicles (locomotives and railcars).
Aircraft
Packard DR-980 9-cylinder diesel aircraft engine, used in the first diesel-engine airplane
In general, diesel engines are not well-suited for planes and helicopters. This is because of the diesel engine's comparatively low
power-to-mass ratio, meaning that diesel engines are typically rather heavy, which is a disadvantage in aircraft. Therefore, there is little need for using diesel fuel in aircraft, and diesel fuel is not commercially used as aviation fuel. Instead, petrol (
Avgas), and
jet fuel (e. g. Jet A-1) are used. However, especially in the 1920s and 1930s, numerous series-production aircraft diesel engines that ran on fuel oils were made, because they had several advantages: their fuel consumption was low, they were reliable, not prone to catching fire, and required minimal maintenance. The introduction of petrol direct injection in the 1930s outweighed these advantages, and aircraft diesel engines quickly fell out of use. With improvements in power-to-mass ratios of diesel engines, several on-road diesel engines have been converted to and certified for aircraft use since the early 21st century. These engines typically run on
Jet A-1
Jet fuel or aviation turbine fuel (ATF, also abbreviated avtur) is a type of aviation fuel designed for use in aircraft powered by gas-turbine engines. It is colorless to straw-colored in appearance. The most commonly used fuels for commercial av ...
aircraft fuel (but can also run on diesel fuel). Jet A-1 has ignition characteristics similar to diesel fuel, and is thus suited for certain (but not all) diesel engines.
Military vehicles
Until World War II, several military vehicles, especially those that required high engine performance (
armored fighting vehicles, for example the
M26 Pershing
The M26 Pershing was a heavy tank/medium tank of the United States Army. It was used in the last months of World War II during the Invasion of Germany and extensively during the Korean War. The tank was named after General of the Armies John J. ...
or
Panther
Panther may refer to:
Large cats
*Pantherinae, the cat subfamily that contains the genera ''Panthera'' and ''Neofelis''
**'' Panthera'', the cat genus that contains tigers, lions, jaguars and leopards.
*** Jaguar (''Panthera onca''), found in So ...
tanks), used conventional otto engines and ran on petrol. Ever since World War II, several military vehicles with diesel engines have been made, capable of running on diesel fuel. This is because diesel engines are more fuel efficient, and diesel fuel is less prone to catching fire. Some of these diesel-powered vehicles (such as the
Leopard 1
The Leopard 1 (also styled Leopard I, before the Leopard 2 simply known as Leopard) is a main battle tank designed and produced by Porsche in West Germany that first entered service in 1965. Developed in an era when HEAT warheads were thought t ...
or
MAN 630
The MAN 630 is a five-tonne lorry, made by German manufacturer Maschinenfabrik Augsburg Nürnberg, from 1953 until 1972. It was made in three major variants, the civilian ''L1'', the military ''L2'', and the civilian ''L3'' with L being an abbrev ...
) still ran on petrol, and some military vehicles were still made with otto engines (e. g.
Ural-375
The Ural-375 is a general purpose 4.5 ton 6×6 truck, which has been produced at the Ural Automotive Plant in the Russian SFSR since 1961. The Ural-375 replaced the ZIL-157 as the standard Soviet Army truck in 1979. It was itself replaced by the ...
or
Unimog 404
The Unimog 404, also called the Unimog S and Unimog 404 S, is a vehicle of the Unimog-series by Mercedes-Benz, produced in the Unimog plant in Gaggenau from 1955 to 1980. Marketed as ''Unimog U82'', and later ''Unimog U110'', 64,242 units of the ...
), incapable of running on diesel fuel.
Tractors and heavy equipment
Today's
tractor
A tractor is an engineering vehicle specifically designed to deliver a high tractive effort (or torque) at slow speeds, for the purposes of hauling a trailer or machinery such as that used in agriculture, mining or construction. Most commo ...
s and
heavy equipment are mostly diesel-powered. Among tractors, only the smaller classes may also offer gasoline-fuelled engines. The
dieselization
Dieselisation (US: dieselization) is the process of equipping vehicles with a diesel engine or diesel engines. It can involve replacing an internal combustion engine powered by petrol (gasoline) fuel with an engine powered by diesel fuel, as o ...
of tractors and heavy equipment began in Germany before World War II but was unusual in the United States until after that war. During the 1950s and 1960s, it progressed in the US as well. Diesel fuel is commonly used in oil and gas extracting equipment, although some locales use electric or natural gas powered equipment.
Tractors and heavy equipment were often
multifuel
Multifuel, sometimes spelled multi-fuel, is any type of engine, boiler, or heater or other fuel-burning device which is designed to burn multiple types of fuels in its operation. One common application of multifuel technology is in military s ...
in the 1920s through 1940s, running either spark-ignition and low-compression engines, akryod engines, or diesel engines. Thus many farm tractors of the era could burn gasoline,
alcohol,
kerosene
Kerosene, paraffin, or lamp oil is a combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in aviation as well as households. Its name derives from el, κηρός (''keros'') meaning "wax", and was regi ...
, and any light grade of
fuel oil
Fuel oil is any of various fractions obtained from the distillation of petroleum (crude oil). Such oils include distillates (the lighter fractions) and residues (the heavier fractions). Fuel oils include heavy fuel oil, marine fuel oil (MFO), bun ...
such as
heating oil, or
tractor vaporising oil
Tractor vaporising oil (TVO) is a fuel for petrol-paraffin engines. It is seldom made or used today. In the United Kingdom and Australia, after the Second World War, it was commonly used for tractors until diesel engines became commonplace, es ...
, according to whichever was most affordable in a region at any given time. On US farms during this era, the name "distillate" often referred to any of the aforementioned light fuel oils. Spark ignition engines did not start as well on distillate, so typically a small auxiliary gasoline tank was used for cold starting, and the fuel valves were adjusted several minutes later, after warm-up, to transition to distillate. Engine accessories such as
vaporizers and
radiator shrouds were also used, both with the aim of capturing heat, because when such an engine was run on distillate, it ran better when both it and the air it inhaled were warmer rather than at ambient temperature. Dieselization with dedicated diesel engines (high-compression with mechanical fuel injection and compression ignition) replaced such systems and made more
efficient use of the diesel fuel being burned.
Other uses
Poor quality diesel fuel has been used as an extraction agent for
liquid–liquid extraction
Liquid–liquid extraction (LLE), also known as solvent extraction and partitioning, is a method to separate compounds or metal complexes, based on their relative solubilities in two different immiscible liquids, usually water (polar) and an orga ...
of
palladium
Palladium is a chemical element with the symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1803 by the English chemist William Hyde Wollaston. He named it after the asteroid Pallas, which was itself na ...
from
nitric acid
Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available nitri ...
mixtures.
Such use has been proposed as a means of separating the
fission product palladium from
PUREX
PUREX (plutonium uranium reduction extraction) is a chemical method used to purify fuel for nuclear reactors or nuclear weapons. PUREX is the ''de facto'' standard aqueous nuclear reprocessing method for the recovery of uranium and plutonium ...
raffinate In chemical separation terminology, the raffinate (from French ''raffiner'', to refine) is a product which has had a component or components removed. The product having the removed materials is referred to as the extract. For example, in solvent ex ...
which comes from used
nuclear fuel.
In this system of solvent extraction, the
hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...
s of the diesel act as the
diluent
A diluent (also referred to as a filler, dilutant or thinner) is a diluting agent. Certain fluids are too viscous to be pumped easily or too dense to flow from one particular point to the other. This can be problematic, because it might not be ...
while the di
alkyl
In organic chemistry, an alkyl group is an alkane missing one hydrogen.
The term ''alkyl'' is intentionally unspecific to include many possible substitutions.
An acyclic alkyl has the general formula of . A cycloalkyl is derived from a cycloalk ...
sulfides act as the extractant.
This extraction operates by a
solvation
Solvation (or dissolution) describes the interaction of a solvent with dissolved molecules. Both ionized and uncharged molecules interact strongly with a solvent, and the strength and nature of this interaction influence many properties of the ...
mechanism.
So far, neither a
pilot plant
A pilot plant is a pre-commercial production system that employs new production technology and/or produces small volumes of new technology-based products, mainly for the purpose of learning about the new technology. The knowledge obtained is then ...
nor full scale plant has been constructed to recover palladium,
rhodium
Rhodium is a chemical element with the symbol Rh and atomic number 45. It is a very rare, silvery-white, hard, corrosion-resistant transition metal. It is a noble metal and a member of the platinum group. It has only one naturally occurring i ...
or
ruthenium
Ruthenium is a chemical element with the symbol Ru and atomic number 44. It is a rare transition metal belonging to the platinum group of the periodic table. Like the other metals of the platinum group, ruthenium is inert to most other chemical ...
from
nuclear waste
Radioactive waste is a type of hazardous waste that contains radioactive material. Radioactive waste is a result of many activities, including nuclear medicine, nuclear research, nuclear power generation, rare-earth mining, and nuclear weapons ...
s created by the use of
nuclear fuel.
Diesel fuel is often used as the main ingredient in oil-base mud drilling fluid.
The advantage of using diesel is its low cost and its ability to drill a wide variety of difficult strata, including shale, salt and gypsum formations.
Diesel-oil mud is typically mixed with up to 40% brine water.
Due to health, safety and environmental concerns, Diesel-oil mud is often replaced with vegetable, mineral, or synthetic food-grade oil-base drilling fluids, although diesel-oil mud is still in widespread use in certain regions.
During development of rocket engines in
Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
during
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
J-2 Diesel fuel was used as the fuel component in several engines including the
BMW 109-718
The BMW 109-718 was a liquid-fuelled rocket engine developed by BMW at their Bruckmühl facility, in Germany during the Second World War.
Development
The 109-718 (109 prefix number for the ''Reichsluftfahrtministerium'', or ''RLM'', desig ...
.
J-2 diesel fuel was also used as a fuel for gas turbine engines.
Chemical analysis
Chemical composition
![Dieselrainbow](https://upload.wikimedia.org/wikipedia/commons/0/06/Dieselrainbow.jpg)
In the United States, petroleum-derived diesel is composed of about 75%
saturated hydrocarbons (primarily
paraffins including
''n'',
''iso'', and
cycloparaffins
Paraffin wax (or petroleum wax) is a soft colorless solid derived from petroleum, coal, or oil shale that consists of a mixture of hydrocarbon molecules containing between 20 and 40 carbon atoms. It is solid at room temperature and begins to m ...
), and 25%
aromatic hydrocarbon
Aromatic compounds, also known as "mono- and polycyclic aromatic hydrocarbons", are organic compounds containing one or more aromatic rings. The parent member of aromatic compounds is benzene. The word "aromatic" originates from the past groupin ...
s (including
naphthalene
Naphthalene is an organic compound with formula . It is the simplest polycyclic aromatic hydrocarbon, and is a white crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass. As an aromati ...
s and
alkylbenzenes
The alkylbenzenes are derivatives of benzene, in which one or more hydrogen atoms are replaced by alkyl groups of different sizes. They are a subset of the aromatic hydrocarbons. The simplest member is toluene, in which a hydrogen atom of the benze ...
). The average chemical formula for common diesel fuel is C
12H
23, ranging approximately from C
10H
20 to C
15H
28.
Chemical properties
Most diesel fuels freeze at common winter temperatures, while the temperatures greatly vary.
Petrodiesel typically freezes around temperatures of −8.1 °C (17.5 °F), whereas biodiesel freezes between temperatures of 2° to 15 °C (35° to 60 °F).
The viscosity of diesel noticeably increases as the temperature decreases, changing it into a gel at temperatures of −19 °C (−2.2 °F) to −15 °C (5 °F), that cannot flow in fuel systems. Conventional diesel fuels vaporise at temperatures between 149 °C and 371 °C.
Conventional diesel
flash point
The flash point of a material is the "lowest liquid temperature at which, under certain standardized conditions, a liquid gives off vapours in a quantity such as to be capable of forming an ignitable vapour/air mixture". (EN 60079-10-1)
The fl ...
s vary between 52 and 96 °C, which makes it safer than petrol and unsuitable for spark-ignition engines.
Unlike petrol, the flash point of a diesel fuel has no relation to its performance in an engine nor to its auto ignition qualities.
Carbon dioxide formation
As a good approximation the chemical formula of diesel is . Note that diesel is a mixture of different molecules. As carbon has a molar mass of 12 g/mol and hydrogen has a molar mass of about 1 g/mol, so the fraction by weight of carbon in EN 590 diesel fuel is roughly 12/14.
The reaction of diesel combustion is given by:
2 + 3n 2n + 2n
Carbon dioxide has a molar mass of 44g/mol as it consists of 2 atoms of oxygen (16 g/mol) and 1 atom of carbon (12 g/mol). So 12 g of carbon yield 44 g of Carbon dioxide.
Diesel has a density of 0.838 kg per liter.
Putting everything together the mass of carbon dioxide that is produced by burning 1 liter of diesel fuel can be calculated as:
The figure obtained with this estimation is close to the values found in the literature.
For gasoline, with a density of 0.75 kg/L and a ratio of carbon to hydrogen atoms of about 6 to 14, the estimated value of carbon emission if 1 liter of gasoline is burnt gives:
Source
Hazards
Environment hazards of sulfur
In the past, diesel fuel contained higher quantities of
sulfur
Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...
.
European emission standards
The European emission standards are vehicle emission standards for pollution from the use of new land surface vehicles sold in the European Union and EEA member states and the UK, and ships in EU waters. The standards are defined in a ser ...
and preferential taxation have forced
oil refineries
An oil refinery or petroleum refinery is an industrial process plant where petroleum (crude oil) is transformed and refined into useful products such as gasoline (petrol), diesel fuel, asphalt base, fuel oils, heating oil, kerosene, lique ...
to dramatically reduce the level of sulfur in diesel fuels. In the European Union, the sulfur content has dramatically reduced during the last 20 years. Automotive diesel fuel is covered in the European Union by standard
EN 590 EN 590 is a standard published by the European Committee for Standardization that describes the physical properties that all automotive diesel fuel must meet if it is to be sold in the European Union and several other European countries.
Based on ...
. In the 1990s specifications allowed a content of 2000 ppm max of sulfur, reduced to a limit of 350 ppm by the beginning of the 21st century with the introduction of Euro 3 specifications. The limit was lowered with the introduction of Euro 4 by 2006 to 50 ppm (
ULSD
Ultra-low-sulfur diesel (ULSD) is diesel fuel with substantially lowered sulfur content. Since 2006, almost all of the petroleum-based diesel fuel available in Europe and North America has been of a ULSD type.
The move to lower sulfur content allo ...
, Ultra Low Sulfur Diesel). The standard for diesel fuel in force in Europe as of 2009 is the Euro 5, with a maximum content of 10 ppm.
In the United States, more stringent emission standards have been adopted with the transition to
ULSD
Ultra-low-sulfur diesel (ULSD) is diesel fuel with substantially lowered sulfur content. Since 2006, almost all of the petroleum-based diesel fuel available in Europe and North America has been of a ULSD type.
The move to lower sulfur content allo ...
starting in 2006, and becoming mandatory on June 1, 2010 (see also
diesel exhaust
Diesel exhaust is the gaseous exhaust produced by a diesel type of internal combustion engine, plus any contained particulates. Its composition may vary with the fuel type or rate of consumption, or speed of engine operation (e.g., idling or at ...
).
Algae, microbes, and water contamination
There has been much discussion and misunderstanding of
algae
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...
in diesel fuel. Algae need light to live and grow. As there is no sunlight in a closed fuel tank, no algae can survive, but some
microbes
A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...
can survive and feed on the diesel fuel.
These microbes form a colony that lives at the interface of fuel and water. They grow quite fast in warmer temperatures. They can even grow in cold weather when fuel tank heaters are installed. Parts of the colony can break off and clog the fuel lines and fuel filters.
Water in fuel can damage a fuel
injection pump
An Injection Pump is the device that pumps fuel into the cylinders of a diesel engine. Traditionally, the injection pump was driven indirectly from the crankshaft by gears, chains or a toothed belt (often the timing belt) that also drives the ca ...
. Some diesel
fuel filter
A fuel filter is a filter used to screens out foreign particles or liquids from the fuel. Most internal combustion engines use a fuel filter, in order to protect the components in the fuel system.
Filters for foreign particles
Unfiltered fuel ...
s also trap water. Water contamination in diesel fuel can lead to freezing while in the fuel tank. The freezing water that saturates the fuel will sometimes clog the fuel injector pump. Once the water inside the fuel tank has started to freeze, gelling is more likely to occur. When the fuel is gelled it is not effective until the temperature is raised and the fuel returns to a liquid state.
Road hazard
Diesel is less flammable than
gasoline / petrol. However, because it evaporates slowly, any spills on a roadway can pose a slip hazard to vehicles.
After the light fractions have evaporated, a greasy slick is left on the road which reduces
tire
A tire (American English) or tyre (British English) is a ring-shaped component that surrounds a Rim (wheel), wheel's rim to transfer a vehicle's load from the axle through the wheel to the ground and to provide Traction (engineering), t ...
grip and traction, and can cause vehicles to skid. The loss of traction is similar to that encountered on
black ice
Black ice, sometimes called clear ice, is a thin coating of glaze ice on a surface, especially on streets. The ice itself is not black, but visually transparent, allowing the often black road below to be seen through it. The typically low level ...
, resulting in especially dangerous situations for two-wheeled vehicles, such as
motorcycle
A motorcycle (motorbike, bike, or trike (if three-wheeled)) is a two or three-wheeled motor vehicle steered by a handlebar. Motorcycle design varies greatly to suit a range of different purposes: long-distance travel, commuting, cruising ...
s and
bicycles, in
roundabout
A roundabout is a type of circular intersection or junction in which road traffic is permitted to flow in one direction around a central island, and priority is typically given to traffic already in the junction.''The New Shorter Oxford En ...
s.
See also
*
Common ethanol fuel mixtures
*
Biodiesel
Biodiesel is a form of diesel fuel derived from plants or animals and consisting of long-chain fatty acid esters. It is typically made by chemically reacting lipids such as animal fat (tallow), soybean oil, or some other vegetable oil with ...
*
Diesel automobile racing
*
Dieselisation
Dieselisation (US: dieselization) is the process of equipping vehicles with a diesel engine or diesel engines. It can involve replacing an internal combustion engine powered by petrol (gasoline) fuel with an engine powered by diesel fuel, as o ...
*
Gasoline
Gasoline (; ) or petrol (; ) (see ) is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignited internal combustion engines (also known as petrol engines). It consists mostly of organic co ...
*
Gasoline gallon equivalent
Gasoline gallon equivalent (GGE) or gasoline-equivalent gallon (GEG) is the amount of an alternative fuel it takes to equal the energy content of one liquid gallon of gasoline. GGE allows consumers to compare the energy content of competing fu ...
*
Hybrid vehicle
*
Liquid fuel
Liquid fuels are combustible or energy-generating molecules that can be harnessed to create mechanical energy, usually producing kinetic energy; they also must take the shape of their container. It is the fumes of liquid fuels that are flammable ...
*
List of diesel automobiles
*
Turbo-diesel
The term turbo-diesel, also written as turbodiesel and turbo diesel, refers to any diesel engine equipped with a turbocharger. As with other engine types, turbocharging a diesel engine can significantly increase its efficiency and power output, ...
* ''
United States vs. Imperial Petroleum
''United States vs. Imperial Petroleum'' is a federal criminal case in which Imperial Petroleum and others are accused of passing off RIN-stripped B99 as pure biodiesel.
Premise
On September 19, 2013, Jeffrey T. Wilson, Craig Ducey, Chad Duce ...
''
*
Winter diesel fuel
Winter diesel fuel (also known as ''winter diesel'', alpine diesel, or winterised diesel) refers to diesel fuel enhanced to prevent it from gelling in cold weather conditions. In general it is achieved by treatment with additives that change the l ...
References
Further reading
* L. D. Danny Harvey, 2010, "Energy and the New Reality 1: Energy Efficiency and the Demand for Energy Services," London:Routledge-Earthscan, , 672 pp.; se
accessed 28 September 2014.
External links
U.S. Department of Labor Occupational Safety & Health Administration: Safety and Health Topics: Diesel Exhaust
{{Authority control
Diesel fuel,
Diesel engines
Hydrocarbon solvents
IARC Group 2B carcinogens
Liquid fuels
Petroleum products