Diesel fuel is a mixture of hydrocarbons obtained by distillation of crude oil. Diesel fuel is used in the diesel engines found in most freight trucks, trains, buses, boats, and farm and construction vehicles. Some cars and small trucks also have diesel engines. It is also used in diesel engine generators to generate electricity. Many industrial facilities, large buildings, institutional facilities, hospitals, and electric utilities have diesel generators for backup and emergency power supply.
The important properties which are used to characterize diesel fuel include cetane number (or cetane index), fuel volatility, density, viscosity, cold behavior, and sulfur content. Diesel fuel specifications differ for various fuel grades and in different countries.
Diesel Fuel Oil D6: also known as residual fuel oil, Diesel Fuel Oil D6 is of high-viscosity and is mostly used for generators. This fuel oil requires preheating to 220 - 260 degrees Fahrenheit, therefore it can’t be used in small boats or cars. However large ships and power plants can use the residual fuel oil.
Diesel Gasoil (D2): also known as gas oil, Diesel Gasoil (D2) is made from refinery Distillate #2 (second distillate derived from crude oil). D2 diesel products contain different levels of sulfur and require no reformers or additives to produce. This type of fuel can be used without additives or reformers. D2 is primarily used as fuel in cars, trucks and many other vehicles.
Diesel S-10: it is a transparent or slightly yellowish coloring fuel, which was commercialized in January 2013, replacing the S-50. It is ideal for supplying SCR and EGR diesel vehicles. In addition to being less polluting, the S-10 has cetane number of 48, against 42 of S-500 diesel and 46 of diesel S-50. That is, it has a higher quality of ignition.