D6 BUNKER FUEL OIL
VIRGIN FUEL OIL/ RESIDUAL FUEL OIL/ BUNKER OIL
D6 Diesel is also known as Residual Fuel Oil / Bunker Fuel Oil , Bunker Oil and is of high-viscosity. This particular fuel oil requires preheating to 220 – 260 Degrees Fahrenheit. D6 is mostly used for generators.
D6 is a type of residual fuel, mainly used in power plants and larger ships. The fuel requires to be preheated before it can be used. It is not possible to use it in smaller engines or vessels/vehicles where it is not possible to pre-heat it. D6 is its name in the USA. In other parts of the world it has other names.
Residual means the material remaining after the more valuable cuts of crude oil have boiled off. The residue may contain various undesirable impurities including 2 percent water and one-half percent mineral soil. D6 fuel is also known as residual fuel oil (RFO), by the Navy specification of Bunker C, or by the Pacific Specification of PS-400.
Recent changes in fuel quality regulation now require further refining of the D6 in order to remove the sulfur, which leads to a higher cost. Despite this recent change, D6 is still less useful because of its viscosity as well as that it needs to be pre-heated before it can be used and contains high amounts of pollutants, such as sulfur. Since it requires pre-heating, it cannot be used in small ships or boats or cars. However large ships and power plants can use the residual fuel oil.

The price of D6 diesel traditionally rises during colder months as demand for heating oil rises, which is refined in much the same way. In many parts of the United States and throughout the United Kingdom and Australia, D6 diesel may be priced higher than petrol.
D6 Diesel Standards and Classification
CCAI and CII are two indexes, which describe the ignition quality of residual fuel oil, and CCAI is especially often calculated for marine fuels.
Despite this marine fuels are still quoted on the international bunker markets with their maximum viscosity (which is set by the ISO 8217 standard – see below) due to the fact that marine engines are designed to use different viscosities of fuel.
The unit of viscosity used is the Centistoke and the d6 fuel most frequently quoted are listed below in order of cost, the least expensive first-
IFO 380 – Intermediate d6 fuel oil with a maximum viscosity of 380 Centistokes
IFO 180 – Intermediate d6 fuel oil with a maximum viscosity of 180 Centistokes
LS 380 – Low-sulphur (<1.5%) intermediate d6 fuel oil with a maximum viscosity of 380 Centistokes
LS 180 – Low-sulphur (<1.5%) intermediate d6 fuel oil with a maximum viscosity of 180 Centistokes
MDO – Marine diesel oil.
MGO – Marine gasoil.
EN-590 DIESEL (ULTRA LOW SULPHER DIESEL)
EN590
EN590 describes the physical properties that all automotive diesel fuel must meet if it is to be sold in the European Union, Croatia, Iceland, Norway and Switzerland.
The EN 590 had been introduced along with the European emission standards. With each of its revisions the EN 590 had been adapted to lower the sulphur content of diesel fuel – since 2007 this is called ultra low sulphur diesel as the former function of sulphur as a lubricant is absent (and needs to be replaced by additives).
The quality of European diesel fuels is specified by the EN 590 standard. While these specifications not are mandatory, they are observed by all fuel suppliers in Europe.
Automobile diesel en 590 is intended for application in diesel engines. Diesel motor fuel quality meets the requirements of European Standard EN 590. For operation in the conditions of a temperate climate following marks of fuel diesel automobile EN 590 are offered: Grade C – limiting filterability temperature -5 ° C; Grade D – limiting filterability temperature -10 ° C; Grade E – limiting filterability temperature – 15 ° C; Grade F – limiting filterability temperature -20 ° C. The entire volume of produced diesel fuel quality meets the requirements for fuels for vehicles of Euro 4 and Euro 5. Low sulfur content in diesel EN 590 reduces emissions of sulfur oxides into the atmosphere, which is especially important for for inhabitants of big cities.