Diesel fuel, also called diesel oil, heavy oil or simply diesel, is any liquid fuel specifically designed for use in a diesel engine, a type of internal combustion engine 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 fuel oil.
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 meant that a proper fuel specifically designed for such engines was needed: diesel fuel.
Aternatives that are not derived from petroleum, such as biodiesel, biomass to liquid (BTL) or gas to liquid (GTL) diesel are increasingly being developed and adopted.
Diesel is a high-volume product of oil refineries.
Diesel fuel can also be used as fuel for several non-diesel engines.
Diesel exhaust, especially from older engines, can cause health damage.
Diesel fuel is produced most commonly being petroleum: Other sources include biomass, animal fat, biogas, natural gas, and coal liquefaction.
Petroleum diesel is the most common type of diesel fuel.
It is produced by the fractional distillation of crude oil between 200 and 350 °C (392 and 662 °F) at atmospheric pressure, resulting in a mixture of carbon chains that typically contain between 9 and 25 carbon atoms per molecule.
Diesel fuels and their combustion products, especially diesel exhaust, have significant adverse health impacts.
Short-term exposure can irritate the eyes, nose, throat, and lungs, causing symptoms like coughing, headaches, nausea, and lightheadedness.
Chronic or long-term exposure is associated with an increased risk of lung cancer and possibly bladder cancer, as well as exacerbation of asthma and other respiratory and cardiovascular conditions.
Acute exposure causes irritation of the airways, coughing, and may trigger or worsen asthma, particularly in vulnerable individuals (like children, the elderly, and those with pre-existing diseases.
Diesel exhaust contains numerous toxic and carcinogenic substances, including benzene, arsenic, and formaldehyde.
There is an increased incidence of lung cancer among occupationally exposed workers.
Diesel exhaust is a Group 1 human carcinogen.
Chronic exposure to fine particulate matter in diesel exhaust has been linked to worsening cardiovascular diseases and increased rates of hospitalizations and premature death among susceptible individuals.
Short-term inhalation may also cause headaches, lightheadedness, eye irritation, or nausea.
Direct skin contact can lead to skin irritation, redness, and, with prolonged exposure, chemical burns.
Eye exposure causes irritation or pain.
Swallowing diesel can cause mouth, throat, and stomach irritation and, if aspirated, chemical pneumonitis.
Long-term exposure to diesel fuelmay promote asthma and allergic diseases in children, reduce lung function, and exacerbate chronic respiratory or heart diseases.
Diesel exhaust is a complex blend including fine and ultrafine particles or soot, nitrogen oxides, and over 40 toxic air contaminants, several of which are known carcinogens.
These particles are small enough to penetrate deep into the lungs, bypassing many natural defense mechanisms and causing inflammation and oxidative stress.
Diesel combustion contributes to urban air pollution, including ozone which further damages lung tissues.
Occupational groups at higher risk include truck drivers, mechanics, warehouse workers, miners, and those working near heavy diesel equipment.
Urban populations, especially those living near high-traffic areas, ports, or industrial sites, are subject to background exposure.
To mitigate risks of diesel fuel exposure: Reducing diesel idling, using cleaner fuels, improving ventilation in occupational settings, and employing HEPA filtration where feasible.
During unhealthy air quality events, staying indoors, using air purifiers, and wearing N95 masks if necessary offer additional protection.
Straight-run diesel is insufficient in supply and quality, so other sources of diesel fuels are blended in.
One major source of additional diesel fuel is obtained by cracking heavier fractions, using visbreaking and coking.
Synthetic diesel can be produced from many carbonaceous precursors but natural gas is most important.
Biodiesel is obtained from vegetable oil or animal fats (biolipids) which is a mainly transesterified with methanol to form fatty acid methyl esters.
It can be produced from many types of oils, the most common being rapeseed oil and soybean oil.
Methanol can also be replaced with ethanol for the transesterification process, which results in the production of ethyl esters.
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.
In the US, diesel is recommended to be stored in a yellow container to differentiate it from kerosene, which is typically kept in blue containers, and gasoline (petrol), which is typically kept in red containers.
The principal measure of diesel fuel quality is its cetane number.
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.
Fuels with higher cetane numbers, normally “premium” diesel fuels with additional cleaning agents and some synthetic content, are available in some markets.
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 CO2 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.
Additional refining is required to remove sulfur, which contributes to a sometimes higher cost.
Reasons for higher-priced diesel include the shutdown of some refineries, diversion of mass refining capacity to gasoline production, and a recent transfer to ultra-low-sulfur diesel (ULSD), which causes infrastructural complications.
Diesel fuel is similar to heating oil, which is used in central heating.
Diesel fuel is mostly used in high-speed diesel engines, especially motor-vehicle diesel engines.
In general, diesel engines are not well-suited for planes and helicopters.
Today’s tractors and heavy equipment are mostly diesel-powered.