Diesel
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- This article is about the fuel. For other uses see diesel (disambiguation).
Diesel fuel is used in a diesel engine invented by Rudolf Diesel, and perfected by Charles F. Kettering. Overwhelmingly the term refers to fuel that is processed from petroleum, but increasingly, alternatives such as biodiesel that are not derived from petroleum are being developed.
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Petroleum diesel
One can obtain diesel from petroleum, which is sometimes called petrodiesel when there is a need to distinguish it from diesel obtained from other sources. As a hydrocarbon mixture, it is obtained in the fractional distillation of crude oil between 250°C and 350°C at atmospheric pressure. Diesel is generally simpler to refine than gasoline and often costs less (though price fluctuations often mean that the inverse is true). However, diesel fuel often contains higher quantities of sulfur. In Europe, emission standards and/or preferrential taxation have forced oil refineries to dramatically reduce the level of sulfur in diesel fuels. Even more stringent diesel emission standards have been adopted in the United States, with the transition to ultra-low sulfur diesel (ULSD) occurring in 2006: see also diesel exhaust. However, the US diesel fuel has lower cetane number (a measure of ignition quality) than European diesel, resulting in worse cold weather performance and some increase in emissions.
Reducing the level of sulfur in diesel is better for the environment. It allows the use of catalytic diesel particulate filters to control diesel particulate emissions, as well as more advanced technologies, such as NOx adsorbers (still under development), to reduce emissions of nitrogen oxides (NOx). However, lowering sulfur also reduces the lubricity of the fuel, meaning that additives must be put into the fuel to help lubricate engines. Biodiesel is an effective lubricity additive.
Diesel contains approximately 18% more energy per unit of volume than gasoline, which along with the greater efficiency of diesel engines contributes to fuel economy (distance traveled per volume of fuel consumed).
In the Maritime field various grades of Diesel fuel are used from Gas Oil to Heavy Fuel Oil:
- Gas Oil - slightly less refined than Diesel for road usage.
- MDO (Marine Diesel Oil) - Thin Diesel, less refined than Gas Oil.
- IFO (Intermediate Fuel Oil)
- MFO (Medium Fuel Oil) - A mixture of HFO and MDO
- HFO (Heavy Fuel Oil) - Thick, dark brown viscous substance. Requires heating to flow.
Chemical composition
Petroleum derived diesel is composed of about 75% saturated hydrocarbons (primarily paraffins including n, iso, and cycloparaffins), and 25% aromatic hydrocarbons (including napthalenes and alkylbenzenes).1
Biodiesel
- Main article: Biodiesel
Biodiesel can be obtained from vegetable oil and animal fats (bio-lipids, using transesterification). Biodiesel is a non-fossil fuel alternative to petrodiesel. It can also be mixed with petrodiesel in any amount in modern engines, though it is a strong solvent and can cause problems in some cases. There have been reports that a diesel-biodiesel mix results in lower emissions than either can achieve alone. A small percentage of biodiesel can be used as an additive in low-sulfur formulations of diesel to increase the lubricating ability that is lost when the sulfur is removed.
Chemically, biodiesel consists of alkyl (usually methyl) esters instead of the alkanes and aromatic hydrocarbons of petroleum derived diesel. However, biodiesel has combustion properties very similar to regular diesel, including combustion energy and cetane ratings.
Uses
Diesel is identical to heating oil, used in central heating. In both Europe and the United States taxes on diesel fuel are higher than on heating oil, and in those areas, heating oil is marked with dye and trace chemicals to prevent and detect tax fraud. In the UK it is known as red diesel, and is also used by agricultural vehicles.
Diesel is used in diesel engines (cars, boats, motorbikes...), a type of internal combustion engine. Rudolf Diesel originally designed the diesel engine to use coal dust as a fuel, but oil proved more effective.
Packard diesel motors were used in aircraft as early as 1927, and Charles Lindbergh flew a Stinson SM1B with a Packard Diesel in 1928. A Packard diesel motor designed by L.M. Woolson was fitted to a Stinson X7654, and in 1929 it was flown 1000 km non-stop from Detroit to Langley, VA. In 1931, Walter Lees and Fredrick Brossy set the nonstop flight record flying a Bellanca powered by a Packard Diesel for 84h 32m.
The first diesel-engine automobile trip was completed on January 6, 1930. The trip was from Indianapolis to New York City - a distance of nearly 800 miles (1300 km). This feat helped to prove the usefulness of the internal combustion engine.
Notes
- Note 1: Agency for Toxic Substances and Disease Registry (ATSDR). 1995. Toxicological profile for fuel oils (http://www.atsdr.cdc.gov/toxprofiles/tp75-c3.pdf). Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service
See also
External links
- Can I use diesel fuel instead of regular gas? (http://www.straightdope.com/mailbag/mdieselvsgas.html) (from The Straight Dope)
- DieselNet.com: US Diesel Fuel (http://www.dieselnet.com/standards/fuels/us.html)
- DieselNet.com: EU Diesel Fuel (http://www.dieselnet.com/standards/fuels/eu.html)de:Dieselkraftstoff
eo:Dizelo es:Petrodiésel fr:Gazole id:Diesel ja:軽油 nl:Diesel no:Diesel ru:Дизельное топливо fi:Dieselöljy zh:柴油